Patent Application
20120152428
The present invention relates to a tire for rim mounting and a tire manufacturing method in which at least a portion of the tire is formed from a resin material, and in particular to a tire formed from a thermoplastic material and a tire manufacturing method of the same.
Pneumatic tires configured with rubber, organic fiber material, and steel members are traditionally employed on vehicles such as cars.
There is demand recently to use materials such as resin materials, thermoplastic resins and thermoplastic elastomers as tire materials due to their advantages from the perspectives of weight reduction, ease of molding, and ease of recycling. For example, a pneumatic tire formed using a thermoplastic polymer material is described in Patent Document 1.
The pneumatic tire of Patent Document 1 is formed with a reinforcement layer made by winding a reinforcement cord around the outside periphery of a tire frame member in a continuous spiral pattern, from such viewpoints of durability, ride comfort and running performance. However, when reinforcement cord is round spirally directly onto the surface of a crown section of a tire frame member formed from a thermoplastic polymer, and another tire structuring member (for example a tread) is laid over the top, gaps can be formed around the periphery of the reinforcement cord (the space between the reinforcement cord and the crown section) resulting in air remaining (air being incorporated). When incorporation of air occurs, even if the reinforcement cord is bonded to the crown section surface by a bonding agent, there is a concern that due to input force during running, the reinforcement cord moves, reducing the durability of the tire. Therefore, in Patent Document 1, incorporation of air at the periphery of the reinforcement cord is suppressed, and movement of the reinforcement cord is suppressed by forming the reinforcement layer by embedding and covering the reinforcement cord in cushion rubber provided to the crown section.
However, in embedding and covering the reinforcement cord, there is a requirement to make the thickness of the cushion rubber needlessly thick. If the thickness of the cushion rubber is increased, it is conceivable that a decrease in running performance could arise due to lateral force being inadequately exerted during running due to various factors such as an increase in weight, an increase in the scale of physical deformation width of members in the thickness direction, and a low modulus of elasticity of the cushion rubber in comparison to a thermoplastic polymer material. Further improvements are required.
The present invention is designed to address the above issues, and an object thereof is to provide a tire with increased durability that suppresses incorporation of air without a reduction in running performance, and a manufacturing method for such a tire.
A tire according to claim 1 includes: a ring shaped tire frame member formed from a frame resin material; and a reinforcement layer formed by winding and joining a covered cord member formed by covering a reinforcement cord with a cord resin material onto an outer peripheral section of the tire frame member.
The tire of claim 1 is configured with the reinforcement layer formed by winding and joining the covered cord member onto the outer peripheral section of the tire frame member formed from a frame resin material. Consequently, characteristics such as the resistance to punctures, cut resistance and the circumferential direction rigidity of the tire (the tire frame member) are raised. By raising the circumferential direction rigidity, creep of the tire frame member formed from the frame resin material (a phenomenon in which there is an increase in plastic deformation of the tire frame member with time under a constant strain) is suppressed.
Note that since the reinforcement cord of the covered cord member is covered by the cord resin material air is suppressed from being incorporated at the periphery of the reinforcement cord, thereby suppressing movement of the reinforcement cord. When a tire structuring member such as a tread is disposed at the outer peripheral side of the reinforcement layer, since the covered cord member is joined to the outer peripheral section, the covered cord member (including the reinforcement cord) is suppressed from moving due to force input during running and durability is increased.
The reinforcement cord is covered by the cord resin material so as to suppress incorporation of air at the periphery of the reinforcement cord, suppressing a reduction in running performance due to such factors as an increase in weight, increased physical displacement width of the member in the thickness direction and insufficient lateral force during running, in comparison to cases in which the reinforcement cord is embedded in a cushion rubber.
A tire of claim 2 is the tire of claim 1 wherein a bonding agent is employed to join the reinforcement cord to the cord resin material.
In the tire of claim 2, adhesion between the reinforcement cord and the cord resin material is raised since the reinforcement cord and the cord resin material are joined together with a bonding agent, thereby further suppressing air from being incorporated at the periphery of the reinforcement cord. Movement of the reinforcement cord is further suppressed by joining the reinforcement cord and the cord resin material together, suppressing deterioration (such as cracking occurring) in the cord resin material.
A tire of claim 3 is the tire of claim 1 or claim 2 wherein: the frame resin material and the cord resin material both have thermoplastic properties; and joining is performed by welding together the outer peripheral section and the covered cord member.
In the tire of claim 3, the joint strength between the outer peripheral section and the covered cord member is raised due to the outer peripheral section and the covered cord member being joined together by welding.
A tire of claim 4 is the tire of claim 3 wherein the frame resin material and the cord resin material are of similar types of material to each other.
In the tire of claim 4 there is good intermixing between the frame resin material and the cord resin material during welding the outer peripheral section and the covered cord member together because the frame resin material and the cord resin material are similar types of material to each other. The joint strength between the outer peripheral section and the covered cord member is accordingly raised.
A tire of claim 5 is the tire of claim 1 or claim 2 wherein the outer peripheral section and the covered cord member are joined together with a bonding agent.
In the tire of claim 5, the outer peripheral section and the covered cord member can be joined together using bonding agent even when materials that are difficult to weld are employed for the frame resin material of the outer peripheral section and the cord resin material of the reinforcement cord member.
A tire of claim 6 is the tire of any one of claim 1 to claim 5 wherein the covered cord member widens in width towards the opposite side to the side joined to the outer peripheral section.
According to a tire of claim 6, joining surface area (joint strength) is secured between the outer peripheral section and the reinforcement cord member due to the covered cord member widening in width towards the opposite side to the side joined to the outer peripheral section.
A tire of claim 7 is the tire of any one of claim 1 to claim 6 wherein the covered cord member has a flat face on the side joined to the outer peripheral section.
According to a tire of claim 7 gaps are less liable to occur between the outer peripheral section and the covered cord member due to the flat face being formed to the covered cord member on the side joined to the outer peripheral section than when the covered cord member has a circular cross-sectional profile, and joining surface area is efficiently secured.
A tire of claim 8 is the tire of any one of claim 1 to claim 7 wherein the covered cord member has a flat face on the opposite side to the side joined to the outer peripheral section.
According to a tire of claim 8 gaps are less liable to occur between the flat face on the opposite side of the covered cord member to the side joined to the outer peripheral section and the inner peripheral face of the tire structuring member when a tire structuring member such as a tread is disposed (joined) to the outer peripheral side of the reinforcement layer due to the covered cord member having a flat face formed on the opposite side to the side joined to the outer peripheral section. Joining surface area is accordingly secured and the joining force between the covering layer and the tire structuring member is raised.
A tire of claim 9 is the tire of any one of claim 1 to claim 8 further including a covering layer that is formed with a covering resin material, that is joined to the outer peripheral section so as to cover the reinforcement layer, and that has an outer peripheral face of flattened profile.
According to a tire of claim 9, gaps occurring between adjacent strands of the covered cord member are covered by the covering layer formed with a flat profile on the outer peripheral face. Gaps are accordingly less likely to occur between the two components and incorporation of air is suppressed when a tire structuring member such as a tread is disposed (joined) to the outer peripheral face of the covering layer, compared to cases in which the tire structuring member is joined to the reinforcement layer in a state in which there are gaps occurring between adjacent strands of covered cord member. Joining surface area (joint strength) is accordingly secured between the tire structuring member and the covering layer, and delamination between the tire structuring member and the covering layer due to input force during running is suppressed, and durability is increased.
A tire of claim 10 is the tire of claim 9 wherein: the covering resin material has thermoplastic properties; and the cord resin material and the covering resin material are similar types of material to each other.
According to a tire of claim 10 there is good intermixing between the cord resin material and the covering resin material at the covered portion, for example when forming the covering layer by covering the reinforcement layer with covering resin material in a molten or softened state since the cord resin material and the covering resin material are similar types of material to each other. The joint strength between the covered cord member and the covering layer is accordingly raised.
A tire of claim 11 includes: a ring shaped tire frame member formed from a frame resin material; a reinforcement layer formed by winding a reinforcement cord onto an outer peripheral section of the tire frame member, and embedding in the outer peripheral section at least a portion of the reinforcement cord as viewed in cross-section along a width direction of the tire frame member; and a covering layer that is formed with a covering resin material and is joined to the outer peripheral section so as to cover the reinforcement layer.
According to a tire of claim 11, the resistance to punctures, cut resistance and the circumferential direction rigidity of the tire (the tire frame member) are raised due to forming the reinforcement layer by winding the reinforcement cord onto the outer peripheral section of the tire frame member formed with the frame resin material. Note that creep of the tire frame member formed with the frame resin material is suppressed by raising the circumferential direction rigidity.
Air is also suppressed from being incorporated at the periphery of the reinforcement cord by embedding in the outer peripheral section at least a portion of the reinforcement cord for forming the reinforcement layer as viewed in cross-section along a width direction of the tire frame member, and covering with the covering layer the portion of the reinforcement cord remaining exposed from the outer peripheral section. The reinforcement cord is accordingly suppressed from moving due to force input during running, and the durability is raised.
The surface of the outer peripheral section is caused to adopt an undulating profile due to embedding in the outer peripheral section at least a portion of the reinforcement cord member forming the reinforcement layer as viewed in cross-section along a width direction of the tire frame member. However, due to the covering layer covering the reinforcement layer, gaps are accordingly less likely to occur between the two components and the incorporation of air is suppressed when a tire structuring member such as a tread is disposed (joined) to the surface of the covering layer (the outer peripheral face of the covering layer), compared to cases in which the tire structuring member is joined to the surface of the outer peripheral section in an undulating state without providing the covering layer. Joining surface area (joint strength) is accordingly secured between the tire structuring member and the covering layer, and delamination between the tire structuring member and the covering layer due to input force during running is accordingly suppressed and durability is raised.
In a pneumatic tire of claim 11, since air is also suppressed from being incorporated at the periphery of the reinforcement cord as described above, there is a reduction in weight and there is no increased physical displacement width of the member in the thickness direction compared to configurations in which the reinforcement cord is embedded in and covered by for example a cushion rubber provided to the outer peripheral section. The modulus of elasticity of the frame resin material (in its solid state) for forming the covering layer is also higher than that of a cushion rubber so sufficient lateral force can be exhibited during running, giving excellent running performance.
A tire of claim 12 is the tire of claim 11 wherein the outer peripheral face of the covering layer has a flattened profile.
According to a tire of claim 12, gaps are less liable to occur between the two components when a tire structuring member such as a tread is provided on the outer peripheral face of the covering layer due to the flattened profile of the outer peripheral face of the covering layer, and so air can be efficiently suppressed from being incorporated.
A tire of claim 13 is the tire of claim 11 or claim 12 wherein: the covering resin material has thermoplastic properties; and the frame resin material and the covering resin material are similar types of material to each other.
According to a tire of claim 13, there is for example good intermixing between the frame resin material of the joining portion (the covered portion) and the covering resin material for example when the covering layer is formed to cover the reinforcement layer with the covering resin material that has been melted or softened, due to the frame resin material and the covering resin material being similar types of material to each other, and so the joint strength between the outer peripheral section and the covering layer is raised.
A tire of claim 14 is the tire of claim 9 or claim 13 wherein: a tire structuring member is provided at the outer peripheral face of the covering layer; and the inner peripheral face of the tire structuring member is profiled so as to conform to the outer peripheral face of the covering layer.
According to a tire of claim 14 the tire structuring member is provided to the outer peripheral face of the covering layer, and since the inner peripheral face of the tire structuring member is profiled so as to conform to the outer peripheral face of the covering layer, gaps are not liable to occur between the covering layer and the tire structuring member, thereby efficiently suppressing air from being incorporated between the two components.
A tire of claim 15 is the tire of claim 14 wherein the tire structuring member is a tread formed from a material with superior abrasion resistance characteristics to those of the frame resin material.
According to a tire of claim 15 the resistance to abrasion is raised due to configuring the tread that makes contact with the road surface of a material with superior abrasion resistance characteristics to those of the frame resin material.
A tire of claim 16 is the tire of any one of claim 9 to claim 15 wherein both end portions of the covering layer in the width direction are positioned further to the outside in the width direction than both width direction end portions of the reinforcement layer as viewed in a cross-section taken along the tire frame member width direction.
According to a tire of claim 16 a wide joining surface area is secured between the outer peripheral section and the covering layer due to both end portions of the covering layer in the width direction being positioned further to the outside in the width direction than both width direction end portions of the reinforcement layer as viewed in a cross-section taken along the tire frame member width direction, namely due to the covering layer being formed over a wider region than the region where the reinforcement layer has been formed. The joint strength between the outer peripheral section and the covering layer is thereby increased.
The tire of claim 17 is the tire of any one of claim 1 to claim 16 further including a bead section formed to the tire frame member, wherein a resin chafer for making rim contact is formed to the bead section.
The resin chafer referred to here is a chafer formed from a resin material, and is formed with a similar profile to a normal rubber chafer of an ordinary rubber tire. Contact to the rim includes cases in which contact is made to a portion of the rim. According to a tire of claim 17 the resin chafer makes contact with the rim when rim assembly is performed for the tire (the tire is assembled to a rim). There is accordingly good rim-fitability, and, since gas (air) filled in the tire does not readily pass out from between the bead section and the rim, there is high internal pressure retaining ability even though the tire frame member is formed from a resin material (frame resin material). The resin chafer is preferably a circular ring shape continuous along the tire circumferential direction, however internal pressure retaining ability raising effect is exhibited even when not continuous.
A tire of claim 18 is the tire of claim 17 wherein the resin chafer extends as far as a side section.
Reference in the present specification to side sections means from the bead section up to the tread edge. The tread edge here indicates the tire width direction outermost ground contact portion when the tire is mounted to a standard rim, as defined in the JATMA YEAR BOOK (2008 edition, Japan Automobile Tire Manufacturers Association standards), inflated to an internal pressure of 100% of the pressure (maximum pressure) corresponding to maximum load (load shown in bold type in the internal pressure—load chart) in the JATMA YEAR BOOK for the applicable size/ply rating, and applied with the maximum load. Where the location of use or manufacturing location uses TRA standards or ETRTO standards then these respective standards are applied.
According to a tire of claim 18 damages to the side sections such as from curbs is easily prevented. The resin chafer may be configured to extend to near to the tread or to the inside of the tread.
A tire of claim 19 is a tire of the claim 17 or claim 18 wherein the resin chafer extends as far as the tire inside of the bead section.
According to a tire of claim 19 the edge of the resin chafer can be more sufficiently prevented from peeling away during rim assembly compared to when the resin chafer is only provided at the tire outside of the bead sections.
A tire of claim 20 is the tire of any one of claim 17 to claim 19 wherein the resin chafer is formed from a chafer resin material having thermoplastic properties.
According to a tire of claim 20 tire manufacturing is better facilitated due to the chafer resin material having thermoplastic properties, in comparison to when the chafer resin material has thermoset properties.
A tire of claim 21 is a tire of any one of claim 1 to claim 16 further including a bead section formed to the tire frame member, wherein a rubber chafer for making rim contact is formed to the bead section.
According to a tire of claim 21 the rubber chafer makes contact with the rim during rim assembly of the tire (assembling the tire and the rim together). There is accordingly good rim-fitability, and since gas (air) filled in the tire does not readily pass out from between the bead section and the rim, there is high internal pressure retaining ability even though the tire frame member is formed from a resin material (frame resin material). The rubber chafer is preferably a circular ring shape continuous along the tire circumferential direction, however internal pressure retaining ability raising effect is exhibited even when not continuous. Contact to the rim obviously includes cases in which contact is made to a portion of the rim.
A tire of claim 22 is the tire of claim 21 wherein the rubber chafer extends as far as a side section.
According to a tire of claim 22 damages to the side sections such as from curbs is easily prevented. The rubber chafer may be configured to extend to near to the tread or to the inside of the tread.
A tire of claim 23 is the tire of claim 21 or claim 22 wherein the rubber chafer extends as far as the tire inside of the bead section.
According to a tire of claim 23 the edge of the rubber chafer can be more sufficiently prevented from peeling away during rim assembly compared to when the rubber chafer is only provided at the tire outside of the bead sections.
A tire manufacturing method of claim 24 is a tire manufacturing method including: a covered cord member forming process of forming a covered cord member by covering a reinforcement cord with a cord resin material; and a covered cord member winding process of winding the covered cord member onto an outer peripheral section of a ring shaped tire frame member formed from a frame resin material and joining the covered cord member to the outer peripheral section.
According to a tire manufacturing method of claim 24, a covered cord member is formed by covering the reinforcement cord with a cord resin material, and the covered cord member is wound onto and joined to the outer peripheral section of the tire frame member. Due to the reinforcement cord being covered with the cord resin material, incorporation of air at the periphery of the reinforcement cord is suppressed, and movement of the reinforcement cord is suppressed.
A tire manufacturing method of claim 25 is the tire manufacturing method of claim 24 wherein in the covered cord member forming process a bonding layer is formed on the outer peripheral face of the reinforcement cord and the cord resin material that has been melted or softened is covered onto and joined to the reinforcement cord through the bonding layer.
According to a tire manufacturing method of claim 25, due to the reinforcement cord being covered and joined to the cord resin material that has been melted or softened through the bonding layer, the reinforcement cord and the cord resin material adhere tightly and the incorporation of air at the periphery of the reinforcement cord is suppressed. Also, by joining the reinforcement cord and the cord resin material, movement of the reinforcement cord is further suppressed, and deterioration of the cord resin material (such as the formation of cracks) is suppressed.
A tire manufacturing method of claim 26 is the tire manufacturing method of claim 25 wherein in the covered cord member forming process the reinforcement cord is cleaned prior to forming the bonding layer.
According to a tire manufacturing method of claim 26, the bonding layer can be formed evenly to the outer peripheral face of the reinforcement cord due to cleaning the reinforcement cord prior to forming the bonding layer. The adhesiveness between the reinforcement cord and the cord resin material is consequently further enhanced and the incorporation of air to the periphery of the reinforcement cord is suppressed. By forming the bonding layer evenly to the outer peripheral face of the reinforcement cord, joining surface area between the reinforcement cord and the cord resin material is also increased, further suppressing movement of the reinforcement cord, and deterioration of the cord resin material (such as the formation of cracks) is suppressed.
A tire manufacturing method of claim 27 is the tire manufacturing method of any one of claim 24 to claim 26 wherein: the frame resin material and the cord resin material both have thermoplastic properties; and in the covered cord member winding process at least one of the cord resin material of the covered cord member and/or the frame resin material of the outer peripheral section at the portion where the covered cord member is to be joined is/are rendered into a molten or softened state, and then the outer peripheral section and the covered cord member are joined together by welding.
According to a tire manufacturing method of claim 27, the strength of the join between the outer peripheral section and the covered cord member is increased due to at least one of the cord resin material of the covered cord member and/or the frame resin material of the outer peripheral section at the portion where the covered cord member is to be joined being rendered into a molten or softened state and then joining the outer peripheral section and the covered cord member together by welding. Note that if both the cord resin material of the covered cord member and the frame resin material of the outer peripheral section at the portion where the covered cord member is to be joined are rendered into a molten or softened state, the frame resin material and the cord resin material will mix together better compared to cases in which only one of them is rendered into a molten or softened state, and the strength of the join between the outer peripheral section and the covered cord member will be increased yet further.
A tire manufacturing method of claim 28 is the tire manufacturing method of any one of claim 24 to claim 26 wherein in the covered cord member winding process the outer peripheral section and the covered cord member are joined together with a bonding agent.
According to a tire manufacturing method of claim 28, by joining the outer peripheral section and the covered cord member together with a bonding agent, it becomes possible to join together the outer peripheral section and the covered cord member even when the frame resin material of the outer peripheral section and the cord resin material of the covered cord member are materials that are difficult to weld.
A tire manufacturing method of claim 29 is the tire manufacturing method of any one of claim 24 to claim 28 wherein in the covered cord member forming process the covered cord member is formed with a width that widens towards the opposite side to the side to be joined to the outer peripheral section.
According to a tire manufacturing method of claim 29, by forming the covered cord member with a width that widens towards the opposite side to the side to be joined to the outer peripheral section, an adequate joining surface area (joint strength) between the outer peripheral section and the reinforcement cord member can be ensured when the covered cord member is wound onto and joined to the outer peripheral section.
A tire manufacturing method of claim 30 is the tire manufacturing method of any one of claim 24 to claim 29 wherein in the covered cord member forming process the covered cord member is formed with a flat face on the side to be joined to the outer peripheral section.
According to a tire manufacturing method of claim 30, by forming the covered cord member with a flat face on the side to be joined to the outer peripheral section, gaps are not liable to form between the outer peripheral section and the covered cord member when the covered cord member is wound onto and joined to the outer peripheral section, and the joining surface area can be effectively ensured. It also becomes possible to wind the covered cord member onto the outer peripheral section without snaking.
A tire manufacturing method of claim 31 is the tire manufacturing method of any one of claim 24 to claim 30 wherein in the covered cord member forming process the covered cord member is formed with a flat face on the opposite side to the side to be joined to the outer peripheral section.
According to a tire manufacturing method of claim 31, by forming the covered cord member with a flat face on the opposite side to the side to be joined to the outer peripheral section, gaps are not liable to form between the flat face on the opposite side of the covered cord member to the side joined to the outer peripheral section and the tire structuring member when the covered cord member has been wound onto and joined to the outer peripheral section and a tire structuring member such as a tread is then joined to the outer peripheral side thereof. An adequate joining surface area is accordingly ensured.
A tire manufacturing method of claim 32 is the tire manufacturing method of any one of claim 24 to claim 31 wherein: the frame resin material and the cord resin material both have thermoplastic properties; and the tire manufacturing method further includes a covered cord member covering process in which the covered cord member embedded in the outer peripheral section is covered by a covering resin material having thermoplastic properties that has been melted or softened.
According to a tire manufacturing method of claim 32, by covering the covered cord member embedded in the outer peripheral section with covering resin material that has been melted or softened, any gaps between neighboring strands of the covered cord member are infilled by the molten or softened covering resin material. The molten or softened covering resin material also spreads outwards to the left and right, and the surface approaches a flat profile. Then, gaps are not liable to form between the two components when a tire structuring member such as a tread is disposed on the surface of the solidified covering resin material, and incorporation of air is effectively suppressed.
A tire manufacturing method of claim 33 is the tire manufacturing method of claim 32 wherein in the covered cord member covering process the covered cord member is covered by the covering resin material that has been melted or softened such that the surface of the covering resin material is further to the radial direction outside than the tire frame member radial direction outside end portion of the covered cord member joined to the outer peripheral section.
According to a tire manufacturing method of claim 33, by covering the covered cord member with the covering resin material that has been melted or softened such that the surface of the covering resin material is further to the radial direction outside than the tire frame member radial direction outside end portion of the covered cord member joined to the outer peripheral section, an even flatter profile is achieved for the surface of the covering resin material.
A tire manufacturing method of claim 34 is the tire manufacturing method of claim 32 or claim 33 wherein in the covered cord member covering process the surface of the covering resin material in a molten or softened state is flattened while pressing towards the covered cord member side.
According to a tire manufacturing method of claim 34, by flattening the surface of the covering resin material that covers the joined covered cord member in a molten or softened state while pressing towards the covered cord member side, the covering resin material is suppressed from lifting away from the outer peripheral section. Furthermore, air is pressed out from between the covering resin material and the outer peripheral section and/or the covered cord member during pressing. The surface of the covering resin material consequently achieves a yet flatter profile.
A tire manufacturing method of claim 35 is the tire manufacturing method of any one of claim 32 to claim 34 wherein in the covered cord member covering process the covering resin material that has been melted or softened is covered over a region wider on both tire frame member width direction sides than the winding region of the covered cord member.
According to a tire manufacturing method of claim 35, by covering the covering resin material that has been melted or softened over a region wider on both tire frame member width direction sides than the winding region of the covered cord member, when surface treatment is carried out in a subsequent process by machining the surface of the cooled and solidified covering resin material, machining of the covered cord member disposed at the edges of the winding region is suppressed.
A tire manufacturing method of claim 36 is the tire manufacturing method of any one of claim 32 to claim 35 wherein in the covered cord member covering process the covered cord member is covered by the covering resin material that has been melted or softened while the cord resin material of the covered cord member joined to the outer peripheral section and the frame resin material at the periphery of the covered cord member are being melted or softened.
According to a tire manufacturing method of claim 36, by covering the covered cord member with the covering resin material that has been melted or softened while the cord resin material of the covered cord member and the frame resin material at the periphery of the covered cord member are being melted or softened, the frame resin material of the covered portions (joining portions), the cord resin material and the covering resin material intermix with each other, and the joint strength between the outer periphery section and the covering layer is increased.
A tire manufacturing method of claim 37 includes: a cord winding process of winding a reinforcement cord onto an outer peripheral section of a ring shaped tire frame member formed from a frame resin material having thermoplastic properties while embedding at least a portion of the reinforcement cord in the outer peripheral section; and a cord covering process of covering the reinforcement cord embedded in the outer peripheral section with a covering resin material having thermoplastic properties that has been melted or softened.
According to a tire manufacturing method of claim 37, at least a portion of the reinforcement cord is embedded in the outer peripheral section of the tire frame member as the reinforcement cord is wound onto the outer peripheral section, and the embedded reinforcement cord is covered by a covering resin material which has been melted or softened. That is to say, by embedding at least a portion of the reinforcement cord in the outer peripheral section and covering the remaining portion that is exposed from the outer peripheral section with a covering resin material that has been melted or softened, incorporation of air at the periphery of the reinforcement cord is suppressed. Also, the covering resin material in a molten or softened state is joined to the frame resin material at the periphery of the reinforcement cord by welding, and movement of the reinforcement cord is suppressed after it has cooled and solidified.
By winding the reinforcement cord onto the outer peripheral section whilst embedding at least a portion of the reinforcement cord in the outer peripheral section, the surface of the outer peripheral section is caused to adopt an undulated state. However, when the reinforcement cord that is embedded in the outer peripheral section is covered with the covering resin material that has been melted or softened, the molten or softened covering resin material spreads out to a certain extent over the surface of the outer peripheral section and the surface of the covering resin material approaches a flat profile (the height difference of the undulations becomes less than that of the surface of the outer peripheral section). In this way, when a tire structuring member such as a tread is joined to the outer peripheral surface of the covering layer during a subsequent process, gaps are less liable to form between the two members, in comparison cases in which a tire structuring member such as a tread is joined to the surface of the outer peripheral section when still in an undulating state without providing a covering layer. Incorporation of air is accordingly suppressed
A tire manufacturing method of claim 38 is the tire manufacturing method of claim 37 wherein in the cord covering process the reinforcement cord is covered by the covering resin material that has been melted or softened such that the surface of the covering resin material is further to the radial direction outside than the tire frame member radial direction outside end portion of the reinforcement cord embedded in the outer peripheral section.
According to a tire manufacturing method of claim 38, by covering the reinforcement cord by the covering resin material that has been melted or softened such that the surface of the covering resin material is further to the radial direction outside than the tire frame member radial direction outside end portion of the reinforcement cord embedded in the outer peripheral section, the surface of the covering resin material achieves an even flatter profile.
A tire manufacturing method of claim 39 is the tire manufacturing method of claim 37 or claim 38 wherein in the cord covering process the surface of the covering resin material in a molten or softened state is flattened while pressing towards the reinforcement cord side.
According to a tire manufacturing method of claim 39, by flattening the surface of the covering resin material in a molten or softened state covered over the embedded reinforcement cord member while pressing towards the reinforcement cord side, the covering resin material is suppressed from lifting away from the outer peripheral section. Also, air is pressed out from between the covering resin material and the outer peripheral section or the reinforcement cord during pressing. The surface of the covering resin material accordingly achieves a yet flatter profile.
A tire manufacturing method of claim 40 is the tire manufacturing method of any one of claim 37 to claim 39 wherein in the cord covering process the covering resin material that has been melted or softened is covered over a region wider on both tire frame member width direction sides than the winding region of the reinforcement cord.
According to a tire manufacturing method of claim 40, by covering the covering resin material that has been melted or softened over a region wider on both tire frame member width direction sides than the winding region of the reinforcement cord, when surface treatment is performed by machining the surface of the cooled and solidified covering resin material in a subsequent process, machining of the reinforcement cord disposed at the edges of the winding region is suppressed.
A tire manufacturing method of claim 41 is the tire manufacturing method of any one of claim 37 to claim 40 wherein in the cord covering process the reinforcement cord is covered by the covering resin material that has been melted or softened while the frame resin material at the periphery of the reinforcement cord embedded in the outer peripheral section is being melted or softened.
According to a tire manufacturing method of claim 41, by covering the reinforcement cord member with the covering resin material that has been melted or softened whilst the frame resin material at the periphery of the reinforcement cord is being melted or softened, the frame resin material of the covered portion (the joining portion) and the covering resin material intermix with each other, and the strength of the join between the outer peripheral section and the covering layer is increased.
A tire manufacturing method of claim 42 is the tire manufacturing method of any one of claim 32 to claim 41 further including a surface treatment process in which the surface of the covering resin material that has cooled and solidified is machined.
According to a tire manufacturing method of claim 42, the surface of the covering resin material that has cooled and solidified is machined. For example, if a tire structuring member such as a tread is bonded to the surface of the covering resin material using a bonding agent, the surface of the covering resin material could be machined to a flat surface in the circumferential direction and the width direction, with fine recesses and projections formed to the surface. By coating a bonding agent on top, the bonding agent would penetrate into the fine recesses and projections, producing an anchor effect between the covering resin material and the tire structuring member such as a tread, and thereby increasing the joint strength between the tread and the covering resin material.
A tire manufacturing method of claim 43 is the tire manufacturing method of any one of claim 24 to claim 42 wherein: the tire frame member is configured from the frame resin material as a frame structuring member at least configuring a bead section; and a resin chafer is formed by injection molding a chafer resin material having thermoplastic properties on the side of the bead section of the frame structuring member to make rim contact.
In a tire manufactured according to the tire manufacturing method of claim 43, the resin chafer makes contact with the rim when the tire is assembled to the rim (the tire and rim assembly). Accordingly, gas is not liable to escape between the bead section and the rim when the inside of the tire is inflated with gas (air), so the internal pressure retaining ability is high even though the frame structuring member is formed from a resin material (the frame resin material).
A tire manufacturing method of claim 44 is the tire manufacturing method of claim 43 wherein when injecting the chafer resin material a bonding agent is coated on the bead section and then the chafer resin material is applied.
According to a tire manufacturing method of claim 44, the adhesive strength between the frame structuring member and the chafer is increased. Furthermore, the position of the chafer resin material can be prevented from misaligning when the resin chafer is being formed. Note that the adhesive strength is increased yet further if the surface of the frame structuring member at the position where the resin chafer is to be formed is buffed using for example sandpaper or a router before the bonding agent is applied. The abraded surface may also be cleaned after buffing, for example with alcohol.
A tire manufacturing method of claim 45 is the tire manufacturing method of any one of claim 24 to claim 42 wherein the tire frame member is configured from the frame resin material as a frame structuring member at least configuring a bead section; and a resin chafer is formed by disposing a chafer resin material having thermoplastic properties on the side of the bead section of the frame structuring member to make rim contact and pressing with a press.
In a tire manufactured according to the tire manufacturing method of the claim 45, the resin chafer makes contact with the rim when the tire is assembled to the rim (the tire and rim assembly). Accordingly, it becomes difficult for gas to escape between the bead section and the rim when the inside of the tire is inflated with gas (air), so the internal pressure retaining ability is high even when the frame structuring member is formed from a resin material (the frame resin material).
A tire manufacturing method of claim 46 is the tire manufacturing method of claim 45 wherein when disposing the chafer resin material a bonding agent is coated on the bead section then the chafer resin material is applied.
According to the tire manufacturing method of claim 46, the adhesive strength between the frame structuring member and the resin chafer is increased. Furthermore, the position of the chafer resin material can be prevented from misaligning when the chafer resin material is being pressed. Note that the adhesive strength is increased yet further if the surface of the frame structuring member for disposing the chafer resin material is buffed using for example sandpaper or a router before the bonding agent is applied. The abraded surface may also be cleaned after buffing, for example with alcohol.
A tire manufacturing method of claim 47 is the tire manufacturing method of any one of claim 43 to claim 46 wherein: a jig is provided inside a cavity of a mold for molding the frame structuring member; a bead core is fixed in contact with the jig from the tire inside direction; and the frame structuring member is formed by pouring the frame resin material that has been melted into the cavity.
According to the tire manufacturing method of claim 47, the frame resin material that has been melted is poured into the cavity with the bead core fixed in a state of contact with the jig from the tire inside direction. That is to say, it becomes possible to pour the frame resin material that has been melted with a jig that prevents displacement of the bead core in a non-contact state with the bead core from the tire outside, or with an auxiliary jig that prevents displacement of the bead core in a state of contact with the bead core from the tire outside at a very small region. Consequently, locations where the frame resin material does not flow in and the bead core is exposed due to the jig being in contact are either not formed at all at the tire outside of the formed frame structuring member, or if they are formed, are formed only at a very small region. The frame resin material is therefore present spanning across every location that will contact the rim, or if there are locations where it is not present then these locations are only at a very small region. It is therefore easy to secure ample air retention ability when assembled to a rim.
Note that the mold may be a mold made of metal, or a mold made of a material other than metal.
Also, although locations are formed at the tire inside of the frame member where the bead core is exposed where the frame resin material cannot flow due to the jig being in contact, there is no impact on the air retention ability when assembled to a rim, even if these locations are large. Jig dimensions and shape can accordingly be achieved capable of securing sufficient ability to prevent rupturing of the frame resin material at the periphery of the bead core during knocking out, and also capable of sufficiently suppressing displacement of the bead core during tire molding.
Note that high pressure pouring may be employed for injection molding when pouring the melted frame resin material. Also, the tire frame member configured from the frame structuring member may be formed with a tube profile with a configuration that allows the inside of the tire frame member to be filled with air.
A tire manufacturing method of claim 48 is the tire manufacturing method of claim 47 wherein when the chafer resin material is injected, or when the chafer resin material is pressed with a press, the chafer resin material infills a cast portion formed in the frame structuring member by removing the jig.
According to the tire manufacturing method of claim 48, a contribution is made to preventing rusting in cases in which the bead core is made from metal, as well as to preventing deterioration of the frame structuring member (the tire frame member) and to preventing damage nucleation from occurring in the frame structuring member (the tire frame member).
A tire manufacturing method of claim 49 is the tire manufacturing method of any one of claim 24 to claim 42 wherein: the tire frame member is configured from the frame resin material as a frame structuring member at least configuring a bead section; and a rubber chafer is formed by disposing green rubber on the side of the bead section of the frame structuring member to make rim contact and vulcanize molding the green rubber while pressing with a press.
In a tire manufactured according to the tire manufacturing method of claim 49, the rubber chafer contacts the rim when the rim assembly is carried out (the assembly of the rim and the tire). Gas is accordingly not liable to escape from between the bead section and the rim even when the tire inside is filled with gas (air), and internal pressure retaining ability is high even though the frame structuring member is formed from a resin material (the frame resin material).
A tire manufacturing method of claim 50 is the tire manufacturing method of claim 49 wherein when disposing the green rubber the bead section is coated with a bonding agent and then the green rubber is applied.
According to the tire manufacturing method of claim 50, the adhesive strength between the frame structuring member and the rubber chafer is increased. It is also possible to prevent displacement of the green rubber when the green rubber is pressed. Note that the adhesive strength is increased yet further if the surface of the frame structuring member for disposing the green rubber is buffed using for example sandpaper or a router before applying the bonding agent. The abraded surface may also be cleaned after buffing, for example with alcohol.
A tire manufacturing method of claim 51 is the tire manufacturing method of any one of claim 24 to claim 42 wherein: the tire frame member is configured from the frame resin material as a frame structuring member at least configuring a bead section; and a rubber chafer is formed by injecting green rubber on the side of the bead section of the frame structuring member to make rim contact and vulcanize molding.
In a tire manufactured according to the tire manufacturing method of claim 51, the rubber chafer contacts the rim when the rim assembly is carried out (the assembly of the rim and the tire). Gas is accordingly not liable to escape from between the bead section and the rim even when the tire inside is filled with gas (air), and internal pressure retaining ability is high even though the frame structuring member is formed from a resin material (the frame resin material).
A tire manufacturing method of claim 52 is the tire manufacturing method of claim 51 wherein when injecting the green rubber the bead section is coated with a bonding agent and then the green rubber is applied.
According to the tire manufacturing method of claim 52, the adhesive strength between the frame structuring member and the rubber chafer is increased. It is also possible to prevent displacement of the green rubber when the green rubber is injected. Note that the adhesive strength is increased yet further if the surface of the frame structuring member for injecting the green rubber is buffed using for example sandpaper or a router before applying the bonding agent. The abraded surface may also be cleaned after buffing, for example with alcohol.
A tire manufacturing method of claim 53 is the tire manufacturing method of any one of claim 49 to claim 52 wherein: a jig is provided inside a cavity of a mold for molding the frame structuring member; a bead core is fixed in contact with the jig from the tire inside direction; and the frame structuring member is formed by pouring the frame resin material that has been melted into the cavity.
According to the tire manufacturing method of claim 53, the frame resin material that has been melted is poured into the cavity with the bead core in a state of contact with the jig from the tire inside direction. That is to say, it becomes possible to pour the frame resin material that has been melted with a jig that prevents displacement of the bead core in a non-contact state with the bead core from the tire outside, or with an auxiliary jig that prevents displacement of the bead core in a state of contact with the bead core from the tire outside at a very small region. Consequently, locations where the frame resin material does not flow in and the bead core is exposed due to the jig being in contact are either not formed at all at the tire outside of the formed frame structuring member, or if they are formed are formed only over a very small region. The frame resin material is therefore present spanning across every location that will contact the rim, or if there are locations where it is not present, they are only over a very small region. It is therefore easy to secure ample air retention ability when assembled to a rim.
Note that the mold may be a mold made of metal, or a mold made of a material other than metal.
Also, although locations are formed at the tire inside of the frame structuring member where the bead core is exposed where the frame resin material does not flow in due to the jig being in contact, air retention ability can be ensured when assembled to a rim even if these locations are large. Jig dimensions and shape are accordingly achieved capable of securing sufficient ability to prevent rupturing of the frame resin material at the periphery of the bead core during knocking out, and also capable of sufficiently suppressing displacement of the bead core during tire molding.
Note that high pressure pouring may be employed for injection molding when pouring the melted frame resin material. Also, the tire frame member configured from the frame structuring member may be formed with a tube profile with a configuration that allows the inside of the tire frame member to be filled with air.
A tire manufacturing method of claim 54 is the tire manufacturing method of claim 53 wherein when the green rubber is pressed by the press or when the green rubber is injected onto the side of the bead section that makes rim contact, the green rubber infills a cast portion formed in the frame structuring member by removing the jig.
According to the tire manufacturing method of claim 54, a contribution is made to preventing rusting of the bead core in cases in which the bead core is made of metal as well as to preventing deterioration of the frame structuring member (the tire frame member) and preventing damage nucleation from occurring in the frame structuring member (the tire frame member).
A tire of the present invention configured as in the above explanation suppresses the incorporation of air and increases durability without decreasing running performance. Furthermore, the tire manufacturing method of the present invention allows the manufacture of a tire that suppresses the incorporation of air and increases durability without a decrease in running performance.
Explanation follows regarding a tire and tire manufacturing method of a first exemplary embodiment of the present invention, with reference to the drawings. As shown in
As shown in
The tire case 17 of the present exemplary embodiment is formed from a single resin material, however the present invention is not limited thereto. Configuration may be made similarly to in a conventional ordinary rubber pneumatic tire, with different resin materials with particular characteristics employed for each of the sections of the tire case 17 (such as the bead sections 12, the side sections 14 and the crown section 16). Reinforcement materials (such as fibers, cords, non-woven fabric or woven fabric made of a high polymer material or a metal) may be embedded in the tire case 17 (such as in the bead sections 12, the side sections 14 and/or the crown section 16) such that the tire case 17 is reinforced by the reinforcement material.
Examples of materials that can be employed as the resin material include thermoset resins, thermoplastic resins and thermoplastic elastomers (TPE) having a resilience similar to that of rubber. Note that the resin materials do not contain vulcanized rubber.
Examples of thermoplastic resins include, for example, urethane resins, olefin resins, vinyl chloride resins and polyamide resins.
Examples of thermoset resins include, for example, phenol resins, urea resins, melamine resins, epoxy resins, and polyester resins.
Examples of thermoplastic elastomers include, for example, amide thermoplastic elastomers (TPA), ester thermoplastic elastomers (TPC), olefin thermoplastic elastomers (TPO), styrene thermoplastic elastomers (TPS), urethane thermoplastic elastomers (TPU), thermoplastic cross-linked rubber (TPV) or other thermoplastic elastomers (TPZ), as defined in JIS K6418. Reference to the same type of resin material indicates an embodiment in which, for example, both are ester types or both are styrene types.
A thermoplastic elastomer is preferably employed as the resin material, in consideration of such factors as the resilience required during running and the formability during manufacturing.
Examples of materials that can be employed as these resin materials include materials with a deflection temperature under load (during loading at 0.45 MPa) of 78° C. or greater as defined by ISO75-2 or ASTM D648, tensile yield strength of 10 MPa or greater as defined by JIS K7113, tensile yield elongation of 10% or greater as similarly defined by JIS K7113, tensile break point elongation (JIS K7113) of 50% or greater as similarly defined by JIS K7113, Vicate softening temperature (method A) of 130° C. or greater as defined by JIS K7206.
A circular ring shaped bead core 18 formed from a steel cord is embedded in each of the bead sections 12 of the present exemplary embodiment, similarly to in a conventional ordinary pneumatic tire. However, the present invention is not limited thereto, and the bead core 18 may be formed from a material other than steel cord, such as an organic fiber cord, an organic fiber cord covered in resin, or a hard resin. The bead core 18 may also be omitted as long as sufficient rigidity of the bead sections 12 is achieved and no problems arise in fitting to the rim 20 (see
As shown in
Preferably a similar type of rubber to that employed on the bead section outer face of a conventional ordinary rubber pneumatic tire is used for the rubber for forming the seal layer 24. The rubber seal layer 24 may be omitted as long as sealing ability can be secured to the rim 20 by the resin material alone. Configuration may be made such that another type of resin material is employed having superior sealing ability to the frame resin material employed for forming the tire case 17.
As shown in
A mono-filament (single strand) such as of metal fiber or organic fiber, or a twisted multi-filament (twisted strands) of such fibers may be employed for the reinforcement cord 26A. The present exemplary embodiment employs a steel cord of twisted steel fiber as the reinforcement cord 26A. The reinforcement layer 28 is equivalent to a belt disposed on the outer peripheral face of a frame of a conventional rubber pneumatic tire.
The reinforcement layer 28 is covered by a covering layer 29. The covering layer 29 is formed from a covering resin material, and the two width direction edge portions of the covering layer 29 are disposed to the width direction outside of the two width direction edge portions of the reinforcement layer 28. Reference to width direction indicates the width direction of the tire case 17 and the tire 10, and the two width direction edge portions of the reinforcement layer 28 indicate the width direction outside edge portions of the covered cord member 26 at the width direction outermost side of the covered cord members 26 forming the reinforcement layer 28. In the present exemplary embodiment configuration is made such that the two width direction edge portions of the covering layer 29 are positioned further to the width direction outside than the two width direction edge portions of the reinforcement layer 28. However, the present invention is not limited thereto, and configuration may be made in which the two width direction edge portions of the covering layer 29 are at the same position in the width direction as the two width direction edge portions of the reinforcement layer 28. The covering layer 29 and the reinforcement layer 28 are joined by welding together the covering resin material and the cord resin material 27.
The outer peripheral face of the covering layer 29 is flat profiled, and a tread 30 configured from a material, for example from a rubber, with superior abrasion resistance characteristics to those of the frame resin material for forming the tire case 17 is joined to the outer peripheral face of the covering layer 29. The inner peripheral face of the tread 30 is profiled to follow the outer peripheral face of the covering layer 29 to achieve a state in which there are no gaps therebetween (a state in which air is not incorporated). The rubber employed in the tread 30 is preferably a similar type of rubber to the rubber employed in a conventional rubber pneumatic tire. Configuration may be made with a tread formed from another type of resin material with superior abrasion resistance characteristics to those of the frame resin material forming the tire case 17 provided in place of the tread 30. A tread pattern configured from plural grooves is formed in the tread 30 in the ground contact surface that contacts the road surface, similarly to in a conventional rubber pneumatic tire.
In the present exemplary embodiment, a thermoplastic material (for example a thermoplastic resin or a thermoplastic elastomer) is selected from resin materials to be employed as an example of the frame resin material for forming the tire case 17. In the present exemplary embodiment, for example, thermoplastic materials are also employed for the covering resin material for forming the covering layer 29 and for the cord resin material 27.
Tire Building Machine
Explanation follows regarding a tire building machine for the tire 10 of the present exemplary embodiment.
The tire support section 40 for supporting the tire case 17 is provided on the end side of the shaft 36. The tire support section 40 is equipped with a cylinder block 38 fixed to the shaft 36, and with plural cylinder rods 41 provided at even spacings around the circumferential direction of the cylinder block 38 and extending towards the radial direction outside.
Tire support plates 42 are provided at the leading ends of the cylinder rods 41. Each of the tire support plates 42 has a circular arc shaped face 42A on the outside face provided with a radius of curvature substantially that of the tire case inner face.
As shown in
In the vicinity of the nozzle 46 are disposed a flatting roller 48, for pressing against the welding thermoplastic material 53 that has been applied to the case section bodies 17A of the tire case 17, and a cylinder device 50 for moving the flatting roller 48 up or down. The cylinder device 50 is supported through a frame, not shown in the drawings, from a support pillar 52 of the extruder 44. The extruder 44 is capable of moving along guide rails 54 disposed on the floor in a direction parallel to the shaft 36 of the building machine 32.
With the extruder 44 it is possible to change over the nozzle 46 to a nozzle 88. The nozzle 88 has an outlet section of a substantially rectangular profile that is wider than the nozzle 46. Accordingly a strip shape of covering resin material 90 of wider width than the welding thermoplastic material 53 can be extruded in a molten or softened state by changing over the material inside the extruder 44 to a covering resin material (see
A cord feeder device 56 for feeding the covered cord member 26 to form the reinforcement layer 28 is movably mounted to the guide rails 54.
As shown in
In the present exemplary embodiment the cord supply device 56 is configured with two rollers, the press roller 60 and the cooling roller 64, however the present invention is not limited to such a configuration and configuration may be made with only one thereof (namely with a single roller). The press roller 60 and the cooling roller 64 are configured to perform rotation following the tire case 17.
The cord heating device 59 is equipped with a heater 70 and a fan 72 for generating hot air and a heating box 74 with an internal space supplied with the hot air, with the covered cord member 26 passing through the internal space of the heating box 74, and a discharge outlet 76 provided at the leading end of the heating box 74 from which the heated covered cord member 26 is discharged.
The cord supply device 56 is capable of movement along the axial direction of the tire case 17.
As a method for forming the bonding layer in the bonding layer forming device 118, a method may be employed in which the cleaned reinforcement cord 26A is passed through a bonding agent tank filled with bonding agent to form the bonding layer on the outer peripheral face, a method may be employed in which bonding agent is sprayed onto the outer peripheral face of the cleaned reinforcement cord 26A, or another method may be employed. Any bonding agent that covers the reinforcement cord 26A and has adhesive properties to the cord resin material 27 may be employed as the bonding agent, and for example a triazine thiol bonding agent is preferably employed.
The cord resin material 27 is preferably a similar type of material to the frame resin material for forming the tire case 17, and particularly preferably the same material. However a different type of material can be employed as long as welding can be achieved. The cord resin material 27 is preferably the same type of material as the covering resin material forming the covering layer 29, and particularly preferably the same material. However a different type of material can be employed as long as welding (adhesion) can be achieved. Furthermore, having the same type of material for the frame resin material for forming the tire case 17, the cord resin material 27 for the covered cord member 26, and the covering resin material for forming the covering layer 29 is preferable from the perspective of joint strength.
The reinforcement cord 26A is fed out from the winding device 122 towards a drum 132 so as to be wound thereon.
The extruder 136 has a resin inlet port 142 at an upper portion, and is configured to melt or soften cord resin material 27 introduced through the resin inlet port 142 so as to cover the reinforcement cord 26A passing through inside the extruder 136. A cord outlet section 144 of the extruder 136 is shaped with a substantially circular profile. In the present exemplary embodiment the covered cord member 26 is accordingly formed with a circular cross-sectional profile. Note that the cord outlet section 144 of the extruder 136 may be configured with a profile other than a substantially circular profile.
The covered cord member 26 is fed out from the winding device 140 to the reel 58 onto which it is then wound.
Explanation follows regarding a manufacturing method of the tire 10 of the present exemplary embodiment.
(1) As shown in
The external diameter of the tire inner face support ring 43 is set at substantially the same dimension as the inner diameter of the outer peripheral portion of the case section bodies 17A, such that the outer peripheral face of the tire inner face support ring 43 is in close contact with the inner peripheral face of the outer peripheral sections of the case section bodies 17A. Accordingly, projections and indentations at the joint portion (the welding thermoplastic material 53), caused by (and in a reciprocal profile to) indentations and projections occurring at the outer periphery of the tire support section 40 due to gaps arising between tire support plates 42, can be suppressed from occurring. Indentations and projections can also be suppressed from arising due to gaps between the tire support plates 42 in laying-up materials (the tire case 17, the tread 30, and other tire building materials (such as, for example, a belt reinforcement layer)). Namely, indentations and projections can be suppressed from arising in the laying-up materials at locations corresponding to gaps between the tire support plates 42 due to forces acting (such as tension and pressing forces) when laying up the laying-up materials. The tire inner face support ring 43 is easily insertable inside the case section bodies 17A by bending deformation due to being formed from thin sheet metal.
Then, as shown in
(2) Next the extruder 44 is moved such that the nozzle 46 is disposed above the abutting portions of the case section bodies 17A, as shown in
Covered Cord Member Forming Process
(3) As shown in
(4) Then, as shown in
Covered Cord Member Winding Process
(5) Then, as shown in
The covered cord member 26 wound out from the reel 58 that was set in the above process is then fed into and heated in the heating box 74 whose internal space is heated by the hot air (for example, the temperature of the outer peripheral face of the covered cord member 26 is heated to about 100 to 200° C.). The cord resin material 27 reaches a molten or softened state at this stage due to the covered cord member 26 being heated.
The heated covered cord member 26 passes through the discharge outlet 76 and is wound in a spiral shape at a constant tension on the outer peripheral face of the crown section 16 of the tire case 17 that is being rotated in the arrow R direction. When this occurs, the molten or softened cord resin material 27 of the portions making contact with the crown section 16 spreads out to the periphery, and the frame resin material and the cord resin material 27 mix together at the contact portions and are welded together. The joint strength between the crown section 16 and the covered cord member 26 is accordingly raised.
The tension applied to the covered cord member 26 is also regulated by applying braking to the reel 58 that is rotating following the rotation of the tire case 17. The covered cord member 26 can be suppressed from snaking by winding the covered cord member 26 while applying a constant tension in this manner. In the present exemplary embodiment tension is regulated by applying braking to the reel 58, however configuration may be made such that the tension is regulated by, for example, providing a tension regulation roller on the conveying path of the covered cord member 26.
Just after the covered cord member 26 with the molten or softened cord resin material 27 makes contact with the outer peripheral face of the crown section 16, the molten or softened cord resin material 27 is spread out to the periphery by pressing with the press roller 60, such that joint surface area to the crown section 16 can be secured. Due to performing such pressing, any air that was incorporated when the covered cord member 26 makes contact with the crown section 16 is squeezed out, and air can be further suppressed from being incorporated between the covered cord member 26 and the crown section 16.
Then the molten or softened cord resin material 27 of the covered cord member 26 is forcibly cooled by the cooling roller 64 provided on the downstream side of the press roller 60. The covered cord member 26 can accordingly be placed with good precision before the covered cord member 26 moves, due to cooling both the covered cord member 26 and the periphery of the covered cord member 26.
The reinforcement layer 28 is formed at the outer peripheral side of the crown section 16 of the tire case 17 by winding the covered cord member 26 in a spiral shape on the crown section 16 in this manner.
Covered Cord Member Covering Process
(6) Then, as shown in
The nozzle 88 is then disposed above a width direction edge portion of a region on the crown section 16 of wider width than the region that has been wound with the covered cord member 28 (the reinforcement layer 28 placement region).
Then, molten or softened covering resin material 90 is extruded from the nozzle 88 towards a covering region on the crown section 16 while rotating the tire support section 40 in the arrow R direction, and the covering resin material 90 is applied along the circumferential direction. The covered cord member 26 is thereby progressively covered by the molten or softened covering resin material 90. When this occurs, due to the molten or softened covering resin material 90 spreading out to a certain extent over the surface of the wound covered cord member 26, gaps between adjacent strands of the covered cord member 26 are filled in with the covering resin material 90, such that the surface approaches a flat profile.
The covering amount of the molten or softened covering resin material 90 covering the wound covered cord member 26 is adjusted such that the surface (entire surface) of the covering resin material 90 extends further to the radial direction outside than the tire case 17 radial direction outside edge portions of the covered cord member 26. The surface of the covering resin material 90 thereby adopts an even flatter profile by such adjustment.
The applied covering resin material 90 is then pressed out evenly by the flatting roller 48 disposed at the downstream side, and the covering resin material 90 is welded to the cord resin material 27. The covering resin material 90 is thereby suppressed from rising up away from the wound covered cord member 26. Also air can also be sufficiently suppressed from being incorporated at the periphery of the covered cord member 26 by any air between the covered cord member 26 and the covering resin material 90 being pressed out during pressing with the flatting roller 48. The reinforcement layer 28 covered with the covering layer 29 is accordingly formed when the covering resin material 90 has solidified through natural cooling.
As shown in
The extruder 44 that was employed for the tire case building process is employed in the present process, however the present invention is not limited thereto, and an extruder dedicated to the present process may be fabricated and employed. However, compared to fabricating a new extruder a cost saving can be achieved by employing the extruder 44 that was employed for the tire case building process and swapping over some of the components.
Surface Treatment Process
(7) The extruder 44 is then retracted, and a buffering device, not shown in the drawings, is disposed in the vicinity of the tire support section 40. Then, while rotating the tire support section 40 in the arrow R direction, the tread joining surface (including the outer peripheral face of the covering layer 29) of the tire case 17 formed with the covering layer 29 for joining to the tread 30 (described in detail later) is machined to adjust the external profile so as to achieve uniformity along the circumferential direction and the width direction, while also performing surface treatment to form fine indentations and projections (including grooves) in the surface. The fine indentations and projections here are provided to give an anchor effect when the tread 30 is joined to the tread joining surface with a bonding agent in the subsequent process. Namely, while in the present exemplary embodiment there are the fine indentations and projections formed on the tread joining surface there is no limitation thereto. The tread joining surface may be formed in any manner that enables an anchor effect to be exhibited.
The covering layer 29 is formed with the covering amount of the covering resin material 90 adjusted such that the surface (entire surface) of the covering resin material 90 is further to the radial direction outside than the tire case 17 radial direction outside end portions of the covered cord member 26. Namely, since a thickness is secured between the covering layer 29 and the covered cord member 26, the reinforcement cord 26A is not liable to be machined away during surface treatment.
(8) The pre-vulcanized strip shaped tread 30 is then wound once around the tread joining surface of the tire case 17, and the tread 30 is bonded to the outer peripheral face of the tire case 17 using a bonding agent, for example. Since the inner peripheral face of the tread 30 also has a flat profile similar to the outer peripheral face of the covering layer 29, gaps are not liable to be formed between the tread joining surface including the outer peripheral face of the covering layer 29 and the inner peripheral face of the tread 30, and air incorporation is thereby suppressed. Due to the fine indentations and projections formed on the tread joining surface in the surface treatment process, the bonding agent enters into the fine indentations and projections and an anchor effect is exhibited, thereby raising the joint strength between the tread 30 and the tire case 17 formed with the covering layer 29.
The bonding agent is not particularly limited, and examples of bonding agents that may be employed include a triazine thiol bonding agent, a chlorinated rubber bonding agent, a phenol resin bonding agent, an isocyanate bonding agent, and a halogenated rubber bonding agent. The tread 30 can, for example, employ a pre-cured tread such as used in a conventional recycled tire. The present process is similar to the process of bonding a pre-cured tread to the outer peripheral face of a tire base in recycled tire manufacturing.
(9) Bonding, such as with a bonding agent, the seal layer 24 formed from pre-vulcanized rubber to the bead sections 12 of the tire case 17 thus completes the tire 10.
(10) Finally the diameter of the tire support section 40 is shrunk, the completed tire 10 is removed from the tire support section 40 and the tire inner face support ring 43 is removed from inside the tire by bending deformation.
Operation
In the tire 10 of the present exemplary embodiment the reinforcement layer 28 is formed by winding the covered cord member 26 on the crown section 16 of the tire case 17 formed from the resin material (frame resin material), raising characteristics such as the resistance to punctures, cut resistance and the circumferential direction rigidity of the tire 10. By raising the circumferential direction rigidity of the tire 10 creep of the tire case 17 formed from the resin material (frame resin material) is prevented.
The reinforcement cord 26A of the covered cord member 26 is covered with the cord resin material 27 and so air can be suppressed from being introduced at the periphery of the reinforcement cord 26A, and movement of the reinforcement cord 26A can also be suppressed. The covered cord member 26 is joined to the crown section 16 by welding, and so the covered cord member 26 (including the reinforcement cord 26A) can be suppressed from moving due to force input during running, thereby raising durability.
Due to the reinforcement cord 26A being covered by the cord resin material 27, suppressing air from being incorporated at the periphery of the reinforcement cord 26A, an increase in weight, increased physical displacement width of the member in the thickness direction, and a reduction in running performance due to such factors as insufficient lateral force during running are accordingly suppressed, compared to configurations in which a reinforcement cord 26A is embedded for example in a cushion rubber.
The reinforcement cord 26A and the cord resin material 27 are joined together with the bonding agent, raising the adhesiveness between the reinforcement cord 26A and the cord resin material 27, and suppressing air from being incorporated at the periphery of the reinforcement cord 26A. Movement of the reinforcement cord 26A is further suppressed by joining together the reinforcement cord 26A and the cord resin material 27, and deterioration (such as crack generation) of the cord resin material 27 is suppressed.
The joint strength of the crown section 16 and the covered cord member 26 is raised due to the crown section 16 and the covered cord member 26 being joined together by welding.
When the frame resin material for forming the tire case 17 and the cord resin material 27 of the covered cord member 26 are the same type of material good intermixing occurs between the frame resin material and the cord resin material 27 during welding the frame resin material and the cord resin material 27 together, thereby raising the joint strength between the crown section 16 and the covered cord member 26.
Gaps occurring between adjacent strands of the covered cord member 26 are also covered by the covering layer 29 so as to provide a flattened profile on the outer peripheral face. Gaps are accordingly not liable to occur between the tread 30 and the tread joining surface of the tire case 17 including the covering layer 29 to which the tread 30 is joined, thereby suppressing air incorporation. Joint surface area (joint strength) is thereby secured between the tread 30 and the covering layer 29, suppressing delamination between the tread 30 and the covering layer 29 due to force input during running, and raising durability.
When a similar type of material is employed for the cord resin material 27 of the covered cord member 26 and the covering resin material of the covering layer 29, since the reinforcement layer 28 is covered by the molten or softened covering resin material 90 to form a covering layer, there is good intermixing between the cord resin material 27 at the covered portion and the covering resin material 90, and the joint strength between the covered cord member 26 and the covering layer 29 is raised.
The resistance to abrasion of the tire 10 is raised by the tread 30 that makes contact with the road surface being formed from a rubber material with superior abrasion resistance properties to those of the frame resin material. Furthermore, due to the ring shaped bead cores 18 formed from a metal material being embedded in the bead sections 12, the tire case 17, namely the tire 10, is retained on the rim 20 with a similar robustness to that of a conventional rubber pneumatic tire.
The seal layer 24 formed from a rubber material with superior sealing properties to those of the frame resin material is also provided to the portions of the bead sections 12 that make contact with the rim 20, and so the sealing ability between the tire 10 and the rim 20 is raised. Air is accordingly further suppressed from leaking out from inside the tire than in cases in which sealing is between the rim 20 and the frame resin material. Rim fit-ability is also raised by providing the seal layer 24.
According to the structure of the tire 10 of the present exemplary embodiment, the tire case 17 formed from the frame resin material provides rigidity without using carcass plies widely employed in conventional rubber tires, and so a reduction in weight can be achieved compared with conventional rubber tires provided with carcass plies. With the structure of the tire 10 of the present exemplary embodiment the number of manufacturing processes during tire manufacture can also be reduced due to not using carcass plies like those of conventional rubber tires.
In the first exemplary embodiment configuration is such that the covered cord member 26 is heated, the cord resin material 27 is melted or softened, and the covered cord member 26 and the crown section 16 are then joined together by welding, however the present invention is not limited thereto. Configuration may be made in which the covered cord member 26 is not heated, but the portion of the crown section 16 where the covered cord member 26 is to be embedded is heated so as to melt or soften the frame resin material, and the covered cord member 26 is then embedded in the crown section 16 and joined thereto. More specifically, as shown in
The first exemplary embodiment is configured such that the covered cord member 26 and the crown section 16 are joined together by welding, however the present invention is not limited thereto. Configuration may be made such that a bonding agent is coated (or sprayed) on the outer peripheral face of the covered cord member 26, and the covered cord member 26 and the crown section 16 joined together with the bonding agent. When joining is by such a bonding agent, the covered cord member 26 and the crown section 16 can be joined even when the frame resin material forming the tire case 17 and the cord resin material 27 are materials that are difficult to weld. A bonding agent layer is formed between the two components when the crown section 16 and the covered cord member 26 have been bonded together employing a bonding agent in this manner.
The first exemplary embodiment is configured such that the covered cord member 26 is formed with a circular cross-sectional profile in the covering cord forming process, however the present invention is not limited thereto. Configuration may be made with the covered cord member 26 having a flat face 26D in cross-section on the side to be joined to the crown section 16, having a flat face 26U on the opposite side to the side to be joined to the crown section 16, and formed with a wider width on the side to be joined to the crown section 16 than on the opposite side (with the flat face 26D having a wider width than the flat face 26U in this case). An example of such a cross-sectional profile is a substantially trapezoidal shape (see
In the first exemplary embodiment configuration is made with the bonding layer formed on the outer peripheral face of the reinforcement cord 26A using the cord bonding layer apparatus 110, however the present invention is not limited thereto. An apparatus may be configured in which the bonding layer is formed on the outer peripheral face of the reinforcement cord 26A by cleaning the reinforcement cord 26A by degreasing in alkali, then cleaning by passing through an acid activation tank, followed by passing through a bonding agent tank containing a bonding agent, cleaning by electrolysis or immersion treatment, cleaning in hot water and then drying in dried hot air.
In the first exemplary embodiment configuration is made such that the molten or softened covering resin material 90 is extruded from the extruder 44 so as to cover the covering region with the covering resin material 90, however the present invention is not limited thereto. As shown in
In the first exemplary embodiment, configuration is made such that the covered cord member 26 is covered by the molten or softened covering resin material 90 after the reinforcement layer 28 has been formed by winding the covered cord member 26 on the crown section 16, however the present invention is not limited thereto. Configuration may be made such that embedded covered cord member 26 is covered by the molten or softened covering resin material 90 while the covered cord member 26 is being embedded in the crown section 16.
Furthermore, while a configuration is adopted in the first exemplary embodiment in which the covered cord member 26 is wound onto the crown section 16 and welding (adhesion) using heat or joining using a bonding agent is performed, the present invention is not limited thereto. Configuration may be made in which the crown section 16 is pre-formed with a spiral shaped groove and the covered cord member 26 fitted into the groove. In such a configuration there is high placement precision when winding the covered cord member 26 on the crown section 16 without the covered cord member 26 snaking. After the covered cord member 26 has been fitted into the groove, the periphery of the covered cord member 26 may be heated so as to weld together the covered cord member 26 and the crown section 16, or the covered cord member 26 and the crown section 16 may be welded together by fitting the pre-heated covered cord member 26 into the groove. Configuration may be made in which the covered cord member 26 that has been coated with a bonding agent is fitted into the groove, thereby joining together the covered cord member 26 and the crown section 16. Configuration may also be made with a thermoset material (for example a thermoset resin) employed as the frame resin material of the tire case 17. When a thermoset material is employed as the frame resin material, a method may be employed, as described above, in which a spiral groove is pre-formed in the crown section 16 (using molding or a cutting process) and the covered cord member 26 that has been coated in a bonding agent is fitted into the groove, thereby joining together the crown section 16 and the covered cord member 26 with a bonding agent.
A thermoset material may also be employed as the cord resin material 27 of the covered cord member 26. A bonding agent may be employed for joining to the crown section 16 when a thermoset material is employed as the cord resin material 27.
A thermoset material may also be employed as the covering resin material of the covering layer 29. A method may be adopted when a thermoset material is employed as the covering resin material in which a bonding agent is pre-coated on the crown section 16 and the covered cord member 26 and then covered over with the molten or softened covering resin material 90.
In the first exemplary embodiment configuration is made such that after the molten or softened covering resin material 90 has been applied to the winding region of the crown section 16 the covering resin material 90 is then left to cool naturally. However the present invention is not limited thereto and configuration may be made in which the covering resin material 90 is force cooled. Examples of force cooling methods include blowing with cold air, and directly cooling the molten or softened covering resin material 90 using a water-cooled cooling roller. The flatting roller 48 described above may also be employed as a cooling roller.
In the first exemplary embodiment configuration is made such that the tire case 17 is configured from the case section bodies 17A, however the present invention is not limited thereto and the tire case 17 may be integrally formed by using a mold, for example.
The tire 10 of the first exemplary embodiment is mounted at the bead sections 12 to the rim 20 such that an air chamber is formed between the tire 10 and the rim 20, in what is referred to as a tubeless tire, however the present invention is not limited thereto. As shown in
In the first exemplary embodiment configuration is made in which the covered cord member 26 is spirally wound on the outer peripheral face of the crown section 16, however the present invention is not limited thereto. Configuration may be made with covered cord members 26 wound such that they are not continuous across the width direction.
Furthermore, in the first exemplary embodiment configuration is made in which the tread 30 is provided on the outer peripheral face of the covering layer 29, however the present invention is not limited thereto. Configuration may be made in which a separate tire structuring member is also provided on the outer peripheral face of the covering layer 29, for example the covered cord member 26 with molten or softened cord resin material 27 may be wound on the outer peripheral face of the covering layer 29, then covered with molten or softened covering resin material 90 so as to form a covering layer, such that layers of tire structuring member are stacked on the tire case 17.
The manufacturing sequence for the tire 10 is also not limited to the example of the first exemplary embodiment and may be changed as appropriate.
Explanation follows regarding a tire and tire manufacturing method of a second exemplary embodiment of the present invention, with reference to the drawings. As shown in
As shown in
The tire case 217 of the present exemplary embodiment is formed from a single resin material, however the present invention is not limited thereto. Configuration may be made similarly to in a conventional ordinary rubber pneumatic tire, with different resin materials with particular characteristics employed for each of the sections of the tire case 217 (such as the bead sections 212, the side sections 214 and the crown section 216). Reinforcement materials (such as fibers, cords, non-woven fabric or woven fabric made of a high polymer material or a metal) may be embedded in the tire case 217 (such as in the bead sections 212, the side sections 214 and/or the crown section 216) such that the tire case 217 is reinforced by the reinforcement material.
Similar materials can be employed as a resin material to those of the first exemplary embodiment.
A circular ring shaped bead core 218 formed from a steel cord is embedded in each of the bead sections 212 of the present exemplary embodiment, similarly to in a conventional ordinary pneumatic tire. However, the present invention is not limited thereto, and the bead core 218 may be formed from a material other than steel cord, such as an organic fiber cord, an organic fiber cord covered in resin, or a hard resin. The bead core 218 may also be omitted as long as sufficient rigidity of the bead sections 212 is achieved and no problems arise in fitting to the rim 220 (see
As shown in
Preferably a similar type of rubber to that employed on the bead section outer face of a conventional ordinary rubber pneumatic tire is used for the rubber for forming the seal layer 224. The rubber seal layer 224 may be omitted as long as sealing ability can be secured to the rim 220 by the resin material alone. Configuration may be made such that another type of resin material is employed having superior sealing ability to the frame resin material employed for forming the tire case 217.
As shown in
As shown in
A mono-filament (single strand) such as of metal fiber or organic fiber, or a twisted multi-filament (twisted strands) of such fibers may be employed for the reinforcement cord 226. The present exemplary embodiment employs a steel cord of twisted steel fiber as the reinforcement cord 226. The reinforcement layer 228 is equivalent to a belt disposed on the outer peripheral face of a carcass of a conventional rubber pneumatic tire.
The outer peripheral face of the covering layer 229 is flat profiled, and a tread 230 configured from a material, for example from a rubber, with superior abrasion resistance characteristics to those of the frame resin material for forming the tire case 217 is provided on the outer peripheral face of the covering layer 229. The inner peripheral face of the tread 230 is profiled to follow the outer peripheral face of the covering layer 229 to achieve a state in which there are no gaps therebetween (a state in which air is not incorporated). The rubber employed in the tread 230 is preferably a similar type of rubber to the rubber employed in a conventional rubber pneumatic tire. Configuration may be made with a tread formed from another type of resin material with superior abrasion resistance characteristics to those of the frame resin material forming the tire case 217 provided in place of the tread 230. A tread pattern configured from plural grooves is formed in the tread 230 in the ground contact surface that contacts the road surface, similarly to in a conventional rubber pneumatic tire.
In the present exemplary embodiment, a thermoplastic material (for example a thermoplastic resin or a thermoplastic elastomer) is selected from resin materials to be employed as an example of the frame resin material for forming the tire case 217. In the present exemplary embodiment, for example, thermoplastic materials are also employed for the covering resin material for forming the covering layer 229.
Tire Building Machine
Explanation follows regarding a tire building machine for the tire 210 of the present exemplary embodiment.
The tire support section 240 for supporting the tire case 217 is provided on the end side of the shaft 236. The tire support section 240 is equipped with a cylinder block 238 fixed to the shaft 236, and with plural cylinder rods 241 provided at even spacings around the circumferential direction of the cylinder block 238 and extending towards the radial direction outside.
Tire support plates 242 are provided at the leading ends of the cylinder rods 241. Each of the tire support plates 242 has a circular arc shaped face 242A on the outside face provided with a radius of curvature substantially that of the tire case inner face.
As shown in
In the vicinity of the nozzle 246 are disposed a flatting roller 248, for pressing against the welding thermoplastic material 253 that has been that has been applied to the case section bodies 217A of the tire case 217, and a cylinder device 250 for moving the flatting roller 248 up or down. The cylinder device 250 is supported through a frame, not shown in the drawings, from a support pillar 252 of the extruder 244. The extruder 244 is capable of moving along guide rails 254 disposed on the floor in a direction parallel to the shaft 236 of the building machine 232.
With the extruder 244 it is possible to change the nozzle 246 over to a nozzle 288. The nozzle 288 has an outlet section of a substantially rectangular profile that is wider than the nozzle 246. Accordingly a strip shape of covering resin material 290 of wider width (for example a width of about 20 mm in the present exemplary embodiment) than the welding thermoplastic material 253 can be extruded in a molten or softened state by changing over the material inside the extruder 244 to a covering resin material (see
A cord feeder device 256 for feeding the reinforcement cord 226 to form the reinforcement layer 228 is movably mounted to the guide rails 254.
As shown in
The cord heating device 259 is equipped with a heater 270 and a fan 272 for generating hot air and a heating box 274 with an internal space supplied with the hot air, with the reinforcement cord 226 passing through the internal space of the heating box 274, and a discharge outlet 276 provided at the leading end of the heating box 274 from which the heated reinforcement cord 226 is discharged.
The cord supply device 256 is capable of movement along the axial direction of the tire case 217.
Explanation follows regarding a manufacturing method of the tire 210 of the present exemplary embodiment.
(1) As shown in
The external diameter of the tire inner face support ring 243 is set at substantially the same dimension as the inner diameter of the outer peripheral portion of the case section bodies 217A, such that the outer peripheral face of the tire inner face support ring 243 is in close contact with the inner peripheral face of the outer peripheral sections of the case section bodies 217A. Accordingly, projections and indentations at the joint portion (the welding thermoplastic material 253), caused by (and in a reciprocal profile to) indentations and projections occurring at the outer periphery of the tire support section 240 due to gaps arising between tire support plates 242, can be suppressed from occurring. Indentations and projections can also be suppressed from arising due to gaps between the tire support plates 242 in laying-up materials (the tire case 217, the tread 230, and other tire building materials (such as, for example, a belt reinforcement layer)). Namely, indentations and projections can be suppressed from arising in the laying-up materials at locations corresponding to gaps between the tire support plates 242 due to forces acting (such as tension and pressing forces) when laying up the laying-up materials. The tire inner face support ring 243 is easily insertable inside the case section bodies 217A by bending deformation due to being formed from thin sheet metal.
Then, as shown in
(2) Next the extruder 244 is moved such that the nozzle 246 is disposed above the abutting portions of the case section bodies 217A, as shown in
Cord Winding Process
(3) Then, as shown in
The reinforcement cord 226 wound out from the reel 258 that was set in the above process is then fed into and heated in the heating box 274 whose internal space is heated by the hot air (for example, the temperature of the reinforcement cord 226 is heated to about 100 to 200° C.).
The heated reinforcement cord 226 passes through the discharge outlet 276 and is wound in a spiral shape at a constant tension on the outer peripheral face of the crown section 216 of the tire case 217 that is being rotated in the arrow R direction. When the heated reinforcement cord 226 makes contact with the outer peripheral face of the crown section 216, the frame resin material at the contact portion is melted or softened, and at least a portion of the heated reinforcement cord 226 is embedded in (enters) the crown section 216. A no-gap state is achieved at this stage between the frame resin material and the reinforcement cord 226, namely a close contact state, due to the heated reinforcement cord 226 being embedded in the molten or softened frame resin material.
Air is accordingly suppressed from being incorporated in the portions where the reinforcement cord 226 is embedded. Melting or softening of the frame resin material at the portions that contact the reinforcement cord 226 is promoted by heating the reinforcement cord 226 to a temperature higher than the melting point of the frame resin material of the tire case 217. The reinforcement cord 226 is thus more easily embedded in the outer peripheral face of the crown section 216, and air can be efficiently suppressed from being incorporated.
The tension applied to the reinforcement cord 226 is also regulated by applying braking to the reel 258 that is rotating following the rotation of the tire case 217. The reinforcement cord 226 can be suppressed from snaking and the amount by which the reinforcement cord 226 is embedded can also be adjusted by winding the reinforcement cord 226 while applying a constant tension in this manner. In the present exemplary embodiment tension is regulated by applying braking to the reel 258, however configuration may be made such that the tension is regulated by, for example, providing a tension regulation roller on the conveying path of the reinforcement cord 226.
Immediately after at least a portion of the heated reinforcement cord 226 has been embedded in the crown section 216, the reinforcement cord 226 is then embedded further by pressing with the press roller 260. The periphery of the embedded portion is flattened at this stage by the press roller 260 and any air that was incorporated during embedding the reinforcement cord 226 is also squeezed out.
Then the portions of the frame resin material that have been melted or softened by the heated reinforcement cord 226 are forcibly cooled by the cooling roller 264 provided on the downstream side of the press roller 260 pressing against the outer peripheral face of the crown section 216. The reinforcement cord 226 can accordingly be placed with good precision, due to cooling the frame resin material at the portions where the reinforcement cord 226 has been embedded before the reinforcement cord 226 moves, and deformation of the frame resin material at the portions where the reinforcement cord 226 has been embedded can be suppressed.
The embedding amount of the reinforcement cord 226 can be regulated by adjusting such factors as the temperature to which the reinforcement cord 226 is heated, the tension caused to act on the reinforcement cord 226, and the pressing force of the press roller 260. In the present exemplary embodiment the reinforcement cord 226 is embedded in the crown section 216 to about half its diameter.
The reinforcement layer 228 is formed at the outer peripheral side of the crown section 216 by winding the heated reinforcement cord 226 in a spiral shape while embedding the reinforcement cord 226 in the crown section 216 in this manner.
Cord Covering Process
(4) Then, as shown in
The nozzle 288 is then disposed above a width direction edge portion of a covering region W2 of wider width than a winding region W1 on the crown section 216 where the reinforcement cord 226 is wound (the reinforcement layer 228 placement region). In the present exemplary embodiment the width direction edge portions of the covering region W2 are set so as to be 2 to 10 mm further to the width direction outside than the width direction edge portions of the winding region W1.
Molten or softened covering resin material 290 is then extruded from the nozzle 288 towards the covering region W2 on the crown section 216 while rotating the tire support section 240 in the arrow R direction, and the covering resin material 290 is applied along the circumferential direction. The reinforcement cord 226 is thereby progressively covered by the molten or softened covering resin material 290. Due to the molten or softened covering resin material 290 spreading out to a certain extent over the surface of the crown section 216 at this stage the surface approaches a flatter profile (smaller top to bottom height differences of undulations) than the surface of the crown section 216 that was caused to undulate by the reinforcement cord 226.
The covering amount of the molten or softened covering resin material 290 when covering the reinforcement cord 226 that has been embedded in the crown section 216 is adjusted such that the surface (entire surface) of the covering resin material 290 extends further to the radial direction outside than the tire case 217 radial direction outside edge portions of the reinforcement cord 226. The surface of the covering resin material 290 thereby adopts an even flatter profile by such adjustment.
The applied covering resin material 290 is then pressed out evenly by the flatting roller 248 disposed at the downstream side, and the covering resin material 290 is welded to the crown section 216. The covering resin material 290 is thereby suppressed from rising up away from the crown section 216. Also air can also be sufficiently suppressed from being incorporated at the periphery of the reinforcement cord 226 by any air between the crown section 216 or the reinforcement cord 226 and the covering resin material 290 being pressed out during pressing with the flatting roller 248. As a result, the portion of the reinforcement cord 226 embedded in the crown section 216 is in close contact with the frame resin material, and the remaining portion of the reinforcement cord 226 exposed from the crown section 216 is in close contact with the covering resin material 290. The covering layer 229 covering the reinforcement layer 228 is accordingly formed when the covering resin material 290 has solidified through natural cooling. The reinforcement cord 226 is accordingly covered by the frame resin material at the embedded portion in the crown section 216 and by the covering resin material of the covering layer 229, such that movement of the reinforcement cord 226 is suppressed.
As shown in
The extruder 244 that was employed for the tire case building process is employed in the present process, however the present invention is not limited thereto, and an extruder dedicated to the present process may be fabricated and employed. However, compared to fabricating a new extruder a cost saving can be achieved by employing the extruder 244 that was employed for the tire case building process and swapping over some of the components.
Surface Treatment Process
(5) The extruder 244 is then retracted, and a buffering device, not shown in the drawings, is disposed in the vicinity of the tire support section 240. Then, while rotating the tire support section 240 in the arrow R direction, the tread joining surface (including the outer peripheral face of the covering layer 229) of the tire case 217 formed with the covering layer 229 for joining to the tread 230 (described in detail later) is machined to adjust the external profile so as to achieve uniformity along the circumferential direction and the width direction, while also performing surface treatment to form fine indentations and projections (including grooves) in the surface. The fine indentations and projections here are provided to give an anchor effect when the tread 230 is joined to the tread joining surface with a bonding agent in the subsequent process. Namely, while in the present exemplary embodiment there are the fine indentations and projections formed on the tread joining surface there is no limitation thereto. The tread joining surface may be formed in any manner that enables an anchor effect to be exhibited.
When no covering layer 229 is provided there is a problem that surface treatment of the tread joining surface cannot be performed due to the reinforcement cord 226 being exposed from the crown section 216. There is an improvement in this respect due to the reinforcement layer 228 configured by the reinforcement cord 226 being covered by the covering layer 229. Furthermore, the covering layer 229 is formed with the covering amount of the covering resin material 290 adjusted such that the surface (entire surface) of the covering resin material 290 is further to the radial direction outside than the tire case 217 radial direction outside end portions of the reinforcement cord 226. Namely, since a thickness is secured between the covering layer 229 and the reinforcement cord 226, the reinforcement cord 226 is not liable to be machined away during surface treatment.
The reinforcement layer 228 is also covered over a wide region (the covering region W2 is made wider than the winding region W1) by the covering layer 229, and so the reinforcement cord 226 (the reinforcement cord at the width direction outermost side) is not machined away when machining the surface of the covering layer 229, facilitating surface treatment. There is also no concern of causing defects in the reinforcement cord 226.
(6) The pre-vulcanized strip shaped tread 230 is then wound once around the outer peripheral face of the tire case 217, and the tread 230 is bonded to the tread joining surface of the tire case 217 using a bonding agent, for example. Since the inner peripheral face of the tread 230 also has a flat profile similar to the outer peripheral face of the covering layer 229, gaps are not liable to be formed between the tread joining surface including the outer peripheral face of the covering layer 229 and the inner peripheral face of the tread 230, and air incorporation is thereby suppressed. Due to the fine indentations and projections being formed on the tread joining surface in the surface treatment process, the bonding agent enters into the fine indentations and projections and an anchor effect is exhibited, thereby raising the joint strength between the tread 230 and the tire case 217 formed with the covering layer 229.
Similar bonding agents can be employed to those of the first exemplary embodiment. The tread 30 can, for example, employ a pre-cured tread such as used in a conventional recycled tire. The present process is similar to the process of bonding a pre-cured tread to the outer peripheral face of a tire base in recycled tire manufacturing.
(7) Bonding, such as with an bonding agent, the seal layer 224 formed from pre-vulcanized rubber to the bead sections 212 of the tire case 217 thus completes the tire 210.
(8) Finally the diameter of the tire support section 240 is shrunk, the completed tire 210 is removed from the tire support section 240 and the tire inner face support ring 243 is removed from inside the tire by bending deformation.
Operation
In the tire 210 of the present exemplary embodiment the reinforcement layer 228 is formed by embedding and winding the reinforcement cord 226 on the crown section 216 of the tire case 217 formed from the resin material (frame resin material), raising characteristics such as the resistance to punctures, cut resistance and the circumferential direction rigidity of the tire 210. By raising the circumferential direction rigidity of the tire 210 creep of the tire case 217 formed from the resin material (frame resin material) is prevented.
As shown in
Furthermore, as shown in
However, in the tire 210 of the present exemplary embodiment the reinforcement layer 228 is covered by the covering layer 229, and the outer peripheral face of the covering layer 229 has a flat profile. The inner peripheral face of the tread 230 also is profiled so as to follow the outer peripheral face of the covering layer 229. Accordingly, gaps are not liable to form between the tread 230 and the covering layer 229 and air can be suppressed from being incorporated between the covering layer 229 and the tread 230. Joining surface area (joint strength) can thereby be secured between the tread 230 and the covering layer 229, and delamination between the covering layer 229 and the tread 230 can be suppressed from occurring due to input, for example, of force during running, raising the durability of the tire 210.
In the tire 210, the reinforcement layer 228 is formed on the crown section 216 of the tire case 217, and the reinforcement layer 228 is covered by the covering layer 229 so as to suppress air from being incorporated at the periphery of the reinforcement cord 226. There is therefore a reduction in weight and no increased physical displacement width of the member in the thickness direction (tire radial direction) compared to configurations in which a reinforcement cord 226 is embedded in and covered by for example a cushion rubber provided to the crown section. The modulus of elasticity of the covering resin material (in its solid state) for forming the covering layer 229 is also higher than that of a cushion rubber so sufficient lateral force can be exhibited during running, giving excellent running performance.
When the frame resin material and the cord resin material are similar types of material, since the covering layer 229 is formed covering the reinforcement layer 228, good intermixing occurs between the frame resin material at the joining portion (the covered portion) and the covering resin material 290, thereby raising the joint strength between the crown section 216 and the covering layer 229.
The resistance to abrasion of the tire 210 is raised by the tread 230 that makes contact with the road surface being formed from a rubber material with superior abrasion resistance properties to those of the frame resin material.
Furthermore, due to the ring shaped bead cores 218 formed from a metal material being embedded in the bead sections 212, the tire case 217, namely the tire 210, is retained on the rim 220 with a similar robustness to that of a conventional rubber pneumatic tire.
The seal layer 224 formed from a rubber material with superior sealing properties to those of the frame resin material is also provided to the portions of the bead sections 212 that make contact with the rim 220, and so the sealing ability between the tire 210 and the rim 220 is raised. Air is accordingly further suppressed from leaking out from inside the tire than in cases in which sealing is between the rim 220 and the frame resin material. Rim fit-ability is also raised by providing the seal layer 224.
According to the structure of the tire 210 of the present exemplary embodiment, the tire case 217 formed from the frame resin material provides rigidity without using carcass plies widely employed in conventional rubber tires, and so a reduction in weight can be achieved compared with conventional rubber tires provided with carcass plies. With the structure of the tire 210 of the present exemplary embodiment the number of manufacturing processes during tire manufacture can also be reduced due to not using carcass plies like those of conventional rubber tires.
The second exemplary embodiment, as shown in
The second exemplary embodiment is configured such that the molten or softened covering resin material 290 is applied across the covering region W2 of the crown section 216 into which the reinforcement cord 226 has been embedded, however the present invention is not limited thereto. Configuration may be made such that the covering resin material 290 is placed when the portion to be covered by the covering resin material 290 (the frame resin material at the periphery of the reinforcement cord 226) has been pre-heated and is in a molten or softened state. The covering resin material 290 and the frame resin material forming the crown section 216 accordingly intermix with each other and weld together, raising the joint strength (weld strength) arising after cooling and solidification between the covering layer 229 and the crown section 216. Delamination accordingly is not liable to occur between the covering layer 229 and the crown section 216. For heating the portion to be covered by the covering resin material 290 heating may be performed by various methods such as, for example, by directly blowing hot air thereon, by radiation heating, by heating by directly pressing with a hot roller, or by heating through irradiation with infrared radiation.
The second exemplary embodiment is configured such that the covering resin material 290 of rectangular cross-sectional profile extruded from the nozzle 246 of the extruder 244 is wound along the circumferential direction in a spiral shape on the covering region W2 of the crown section 216, however the present invention is not limited thereto. A nozzle may be employed with an outlet to extrude the covering resin material 290 of a width similar to the overall width of the covering region W2 such that the covering region W2 is covered by the covering resin material 290 in a single pass. Such a wide mouthed nozzle may also be employed in the extruder 244 of the first exemplary embodiment.
The second exemplary embodiment is also configured such that the molten or softened covering resin material 290 is extruded from the extruder 244 to cover the covering region W2, however the present invention is not limited thereto. Configuration may be made such that, as shown in
In the cord winding process of the second exemplary embodiment the reinforcement cord 226 is heated, and the reinforcement cord 226 is embedded in the crown section 216 while the contact portion of the crown section 216 is being melted or softened by the heated reinforcement cord 226, however the present invention is not limited thereto. Configuration may be made such that the reinforcement cord 226 is not heated, the portion of the crown section 216 where the reinforcement cord 226 is to be embedded is heated, and the reinforcement cord 226 is embedded when the frame resin material of the heated portion has achieved a molten or softened state.
Configuration may also be made such that the portion of the crown section 216 where the reinforcement cord 226 is to be embedded is heated, and the heated reinforcement cord 226 is embedded when the frame resin material of the heated portion has achieved a molten or softened state. Air can be more efficiently suppressed from being incorporated at the periphery of the reinforcement cord 226 when both the portion of the crown section 216 where the reinforcement cord 226 is to be embedded and the reinforcement cord 226 are heated than in cases in which only one of the components is heated.
Various methods may be employed for heating the portion of the crown section 216 where the reinforcement cord 226 is to be embedded, such as heating by application of hot air, heating with radiation heat, heating with infrared radiation, or heating by pressing a heated roller thereon.
The second exemplary embodiment is configured such that after the molten or softened covering resin material 290 has been applied to the winding region W1 of the crown section 216 the covering resin material 290 is then left to cool naturally. However the present invention is not limited thereto and configuration may be made in which the covering resin material 290 is force cooled. Examples of force cooling methods include blowing with cold air, and directly cooling the molten or softened covering resin material 290 using a water-cooled cooling roller. The flatting roller 248 described above may also be employed as a cooling roller.
The second exemplary embodiment is configured such that after forming the reinforcement layer 228 by winding the reinforcement cord 226 on the crown section 216 while embedding the reinforcement cord 226, the molten or softened covering resin material 290 is then employed to cover the reinforcement cord 226, however the present invention is not limited thereto. Configuration may be made such that the reinforcement cord 226 is covered by the molten or softened covering resin material 290 while the reinforcement cord 226 is being embedded in the crown section 216.
The second exemplary embodiment is configured such that the crown section 216 is made molten or softened and the reinforcement cord 226 embedded, however the present invention is not limited thereto. Configuration may be made in which the crown section 216 is pre-formed with a spiral groove, and the reinforcement cord 226 is then embedded in the groove. Such a configuration enables the reinforcement cord 226 to be placed with high precision without snaking when winding the reinforcement cord 226 on the crown section 216.
Configuration may also be made with a thermoset material (for example a thermoset resin) employed as the frame resin material of the tire case 217. When a thermoset material is employed as the frame resin material, a method may be employed, as described above, in which a spiral groove is pre-formed in the crown section 216 (using molding with a mold or a cutting process) and the reinforcement cord 226 fitted into the groove and covered with the molten or softened covering resin material 290. A method may also be employed in which the crown section 216 and the reinforcement cord 226 are joined by a bonding agent by fitting the reinforcement cord 226 that has been coated with the bonding agent into the groove. A thermoset material may also be employed as the covering resin material of the covering layer 229. When a thermoset material is employed as the covering resin material a method may be adopted in which a bonding agent is pre-coated onto the crown section 216 and the reinforcement cord 226 and then covered over with the molten or softened covering resin material 290.
In the second exemplary embodiment configuration is made such that the tire case 217 is configured from the case section bodies 217A, however the present invention is not limited thereto and the tire case 217 may be integrally formed by using a mold, for example.
The tire 210 of the second exemplary embodiment is mounted at the bead sections 212 to the rim 220 such that an air chamber is formed between the tire 210 and the rim 220, in what is referred to as a tubeless tire, however the present invention is not limited thereto. As shown in
In the second exemplary embodiment configuration is made in which the reinforcement cord 226 is spirally wound on the outer peripheral face of the crown section 216, however the present invention is not limited thereto. Configuration may be made with reinforcement cords 226 wound such that they are not continuous across the width direction.
Furthermore, in the second exemplary embodiment configuration is be made in which the tread 230 is provided on the outer peripheral face of the covering layer 229, however the present invention is not limited thereto. Configuration may be made in which a different tire structuring member is provided on the outer peripheral face of the covering layer 229. For example the outer peripheral face of the covering layer 229 may be melted or softened, and then a different reinforcement cord embedded in the outer peripheral face of the covering layer 229, then covered with molten or softened covering resin material 290 such that layers of tire structuring member are stacked on the crown section 216.
The manufacturing sequence for the tire 210 is also not limited to the example of the second exemplary embodiment and may be changed as appropriate.
In the present exemplary embodiment the relationship between the winding region W1 and the covering region W2 (the width direction edge portions of the covering region W2 being 2 to 10 mm to the width direction outside of the width direction edge portions of the winding region W1) may be applied as appropriate to the first exemplary embodiment. The overlap amount H during application of the covering resin material 290 to the crown section 216 in the present exemplary embodiment (overlapping width direction edge portions with each other by 0.5 mm to 5 mm) may also be applied as appropriate to the first exemplary embodiment.
Explanation follows regarding of a tire and tire manufacturing method of a third exemplary embodiment of the present invention, with reference to the drawings. As shown in
The tire 310 is equipped with a ring shaped tire case 317 (serving as an example of a tire frame member) formed from a frame resin material and configured by: a pair of bead sections 12 (see
The tire case 317 is formed from circular ring shaped case section bodies 317A (frame structuring members) each formed in the same shape such as by molding in a mold with a bead section configuring portion 312M for covering the bead core 18 of one of the bead sections 12, one of the side sections 14 and a half-width crown section 16 integrated together. The case section bodies 317A are aligned to face each other and are joined together along the tire center CL. The tire case 317 is not limited to being formed by joining together two members, and may be formed by joining together three or more members, or may be formed as a single body including the pair of bead sections 12, the pair of the side sections 14 and the crown section 16.
As shown in
The case section bodies 317A are formed from a resin material (frame resin material). A similar resin material to that employed in the first exemplary embodiment can be employed as the resin material in the present exemplary embodiment. The case section bodies 317A can be formed, for example, by vacuum molding, pressure molding, or injection molding, melt-casting. Manufacturing processes can accordingly be greatly simplified in comparison to molding (vulcanization) in rubber, and the time for molding can also be shortened.
In the present exemplary embodiment the case section bodies 317A are formed with left-right symmetry, namely one of the case section bodies 317A is the same shape as the other of the case section bodies 317A. This has the advantage of allowing the case section bodies 317A to be formed with a single type of mold.
In the present exemplary embodiment the contact portion of the bead sections 12 to the rim 20, at least the portion that makes contact with the rim flange 22 of the rim 20, is formed with the circular ring shaped resin chafer 324 formed from a material having superior sealing ability (gas sealing performance) to the frame resin material forming the tire case 317. The modulus of elasticity of the resin chafer 324 is preferably the modulus of elasticity of the tire case 317 or lower, and more preferably 70% of the modulus of elasticity of the tire case 317 or lower. The modulus of elasticity of the resin chafer 324 is particularly preferably 50% of the modulus of elasticity of the tire case 317 or lower. When a resin with excellent abrasion resistance is employed as the chafer resin material for the resin chafer 324 the modulus of elasticity of the resin chafer 324 is even more preferably 25% of the modulus of elasticity of the tire case 317 or lower.
The tire case 317 and the resin chafer 324 can be formed by various resin materials with excellent rigidity and sealing performance.
The resin chafer 324 may extend to the portion that contacts the bead seat section 21, and may also extend to the tire inside (tire inside face).
In the present exemplary embodiment, as an example, a thermoplastic material (such as for example a thermoplastic resin or a thermoplastic elastomer) is selected from resin materials as the frame resin material for forming the tire case 317. A thermoplastic material (such as for example a thermoplastic resin or a thermoplastic elastomer) is also, as an example, selected from resin materials as the chafer resin material for forming the resin chafer 324.
Explanation follows regarding a manufacturing method of the tire 310 of the present exemplary embodiment. In the following explanation the case section bodies 317A are formed by injection molding (see
In the present exemplary embodiment a mold 340 is employed, as shown in
As shown in
When the contact length L of the jigs 346 to the bead core 18 along the tire circumferential direction is 15 mm or less then stress is not liable to be concentrated in the case section bodies 317A. Such an effect is more readily achieved when the length L is 5 mm or less. The contact length L is preferably 1 mm or longer from the perspective of the strength of the jigs 346.
In the present exemplary embodiment, each of the jigs 346 are formed from a magnetic member. There are 12 individual jigs 346 disposed at even intervals along the bead core housing location.
A recess portion 347 (see
As shown in
In the present exemplary embodiment, first the mold 340 is opened, the tire inside portion of the bead core 18 is inserted into the recess portion 347 of each of the jigs 346, and the mold 340 closed up. The bead core 18 is formed from a body with magnetic properties so as to enable magnetic attachment. Melted frame resin material is then poured into the mold 340 from the gate 348, and the case section body 317A is formed by injection molding.
During pouring the frame resin material is poured from the gate 348 through between the bead core 18 and the outer mold 342 at the positions where the jigs 346 are provided, and so the bead core 18 is pressed from the tire outside towards the tire inside. The moving force bearing on the bead core 18 can accordingly be sufficiently supported by the jigs 346. It is thus possible to pour the melted frame resin material with the jigs 346, for preventing displacement of the bead core 18, in a state in which there is no contact of the jigs 346 to the bead core 18 from the tire outside.
The case section body 317A manufactured with the bead core 18 held in this manner is then removed from the mold 340, and as shown in
In the present exemplary embodiment the case section body 317A is housed in the injection molding mold 370, the mold 370 closed, and then the chafer resin material poured from the gate 378 and vulcanize molding performed. The resin chafer 324 is accordingly formed to the case section body 317A, as shown in
The method for joining together the case section bodies 17A of the first exemplary embodiment is then employed to join together the case section bodies 317A, forming the tire case 317.
Note that the case section bodies 317A may be joined together first and then the resin chafer 324 formed.
Then the reinforcement layer 28, the covering layer 29 and the tread 30 are formed on the tire case 317 by similar methods to those of the first exemplary embodiment. This completes manufacture of the tire 310 (see
As explained above, in the present exemplary embodiment the resin chafer 324 is formed by injection molding resin material (frame resin material) onto the bead section configuring portion 312M of the tire case 317. The resin chafer 324 accordingly makes rim contact when the tire is assembled to the rim, and air is not liable to escape from between the bead sections 12 and the rim 20 even when air is filled in the tire 310. There is accordingly high internal pressure retaining ability even though the tire case 317 is formed from a resin material (frame resin material).
The side sections 14 and the tread section (the crown section 16) are also formed to the tire case 317 and the two case section bodies 317A are joined together along the tire center CL using a welding thermoplastic material (not shown in the drawings). Tire strength is accordingly efficiently raised.
The resin chafer 324 also extends to the tire inside (tire inside face) of the bead sections 12. There is accordingly less concern of the edge of the resin chafer 324 peeling away during rim assembly than for cases in which the resin chafer 324 is only provided to the tire outside of the bead sections 12.
When the case section bodies 317A are manufactured melted frame resin material is poured into the cavity with the bead core 18 in a contact state with the jigs 346 from the direction that will be at the tire inside. Namely, it is thus possible to pour the melted frame resin material with the jigs 346 for preventing displacement of the bead core 18 in a state in which the jigs 346 do not contact the bead core 18 from the tire outside. According the regions A, where the jigs 346 were in contact with the bead core 18 such that there is no frame resin material present and the bead core 18 is exposed, are not formed at all on the tire outside of the case section bodies 317A. There is accordingly frame resin material present spanning across every location that will make contact with the rim 20, facilitating securing sufficient air retention ability when assembled to a rim.
There are regions A formed at the tire inside of the case section bodies 317A where the jigs 346 were in contact with the bead core 18 such that there is no solidified frame resin material present and the bead core 18 is exposed. However, air retention ability can be maintained when assembled to a rim even with a relatively large dimension for the regions A. Jig dimensions and shape are accordingly achieved capable of securing sufficient ability to prevent rupturing of the frame resin material at the periphery of the bead core during knocking out, and also capable of sufficiently suppressing displacement of the bead core 18 during tire molding. Not only is displacement of the bead core 18 suppressed but deformation of the bead core 18 due to pressure applied thereto during molding can also be prevented.
Such an advantageous effect is obtained even when high pressure pouring is employed for injection molding when pouring the melted frame resin material.
The bead core 18 is readily retained by the jigs 346 since the jigs 346 are formed from magnets in the present exemplary embodiment. Configuration may be made employing a jig that is covered with a shielding member to stop magnetic force being dissipated in directions other than the direction of the bead core 18.
The jigs 346 are disposed at plural locations along the bead core housing location. The positioning precision of the bead core 18 can accordingly be further raised. When pouring the frame resin material the frame resin material is poured between the bead core 18 and the outer mold 342 for molding the tire outside. The bead core 18 is accordingly pressed from the tire outside towards the tire inside during pouring. The movement force bearing on the bead core 18 can accordingly be sufficiently supported with the jigs 346.
Configuration may be made such that by changing the shape of the molding face of the outer mold 372 the shape of the space Z (see
The joining faces of the bead section configuring portion 312M and the resin chafer 324 may be profiled with recesses and projections to obtain an anchor effect (strong meshing effect, like that of dropping an anchor) in order to raise the joint strength between the bead section configuring portions 312M of the case section bodies 317A and the resin chafers 324.
For example, as shown in
The depth of the recesses and projections for obtaining such an anchor effect is preferably 2 mm or less, and more preferably 1 mm or less. A dropping off in the strength of the molded item might conceivably occur with a depth of greater than 2 mm. However, it is difficult to obtain sufficient anchor effect when the depth of recesses and projections is less than 0.05 mm.
The molding face of a mold may be pre-formed with a corresponding recessed and projected profile in order to form such a recessed and projected profile.
In order to further prevent displacement of the bead core 18 configuration may be made with an auxiliary jig 362 provided that has a variable setting position in the direction of intruding-retracting in the cavity S, as shown in
After the case section body 317A has been molded it is also possible to not use the inner mold 374, but instead to leave the case section body 317A disposed in the inner mold 344 and only remove the outer mold 342. The outer mold 372 is then disposed thereon and the resin chafer 324 formed by injection molding with the chafer resin material.
Explanation has been given in the present exemplary embodiment of a case in which the resin chafer 324 is formed by injection molding, however a two color molding machine may be employed, and the resin chafer 324 molded in the same mold after a portion of the case section body 317A has been molded.
Configuration may be made in which a single or double layered bonding agent layer is coated on the surface of the case section bodies 317A at positions for forming the resin chafer 324. The bonding force is raised in such cases by buffing abrasion such as with sandpaper to the surface at the locations to be coated with the bonding agent. Preferably a certain amount of drying is performed after coating the bonding agent in order to raise the bonding force. Accordingly coating the bonding agent is preferably performed in an atmosphere with a relative humidity of 70% or less. The bonding agent here may, for example, be a triazine thiol bonding agent, however a chlorinated rubber bonding agent, a phenol resin bonding agent, an isocyanate bonding agent, or a halogenated rubber bonding agent may also be employed without particular limitation.
A thermoset material (for example a thermoset resin) may be employed as the chafer resin material. When the chafer resin material is a thermoset resin material the resin chafer is also formed by injection molding a chafer resin material onto the case section bodies 317A in a similar manner to in the third exemplary embodiment.
Explanation follows regarding a tire manufacturing method of a fourth exemplary embodiment. In the present exemplary embodiment, as shown in
A resin chafer molding face 456 is formed on the upper mold 452, the case section body 317A is set in the lower mold 451, and a specific dimension of chafer resin material R (preferably a thermoplastic elastomer in the present exemplary embodiment) for forming a resin chafer 464 is placed in a bead section configuring portion 312M of the case section body 317A. When the upper mold 452 is lowered and the molding face (bottom face) of the upper mold 452 is pressed against the side section 14 of the case section body 317A a space is formed between the upper mold 452 and the bead section configuring portion 312M enabling a resin chafer of a set shape to be vulcanize molded. A spew molding through hole 458 is also formed in the upper mold 452.
In the present exemplary embodiment, the case section body 317A and the chafer resin material R are set in the lower mold 451. The upper mold 452 is lowered to a set position and the chafer resin material R compression molded, and the chafer resin material R heat welded by subjecting the chafer resin material R to a specific temperature for a specific duration. As a result the resin chafer 464 formed from a thermoplastic material is formed (see
When disposing the chafer resin material R in the present exemplary embodiment, the chafer resin material R is placed at locations to cover the regions A referred to above when the chafer resin material R is pressed by the press 450. Configuration may be made in which a single or double layered bonding agent layer is coated on the surface of the case section body 317A at the positions where the chafer resin material R is to be set. The bonding force is raised in such cases by buffing abrasion such as with sandpaper to the surface at the locations to be coated with the bonding agent. Preferably a certain amount of drying is performed after coating the bonding agent in order to raise the bonding force. Accordingly coating of the bonding agent is preferably performed in an atmosphere with a relative humidity of 70% or less. The bonding agent here may, for example, be a triazine thiol bonding agent, however a chlorinated rubber bonding agent, a phenol resin bonding agent, an isocyanate bonding agent, or a halogenated rubber bonding agent may also be employed without particular limitation.
Then, similarly to in the fourth exemplary embodiment, the two case section bodies 317A are joined together to produce the tire case 317, and the tire case 317 is formed with the reinforcement layer 28, the covering layer 29 and the tread 30. This completes production of the tire 310.
In the present exemplary embodiment the resin chafer 464 is formed by compression molding the chafer resin material R onto the bead section configuring portion 312M of the case section body 317A formed from the frame resin material, and by joining such as by heat welding. The resin chafer 464 accordingly makes contact with a rim when the tire is assembled to a rim, and so air is not liable to come out from between the bead section and the rim even when air is filled in the tire 310. High internal pressure retaining ability is accordingly achieved even though the tire case 317 is formed from a resin material (the frame resin material).
A reduction in the manufacturing time is achieved by disposing the chafer resin material R on the bead section configuring portion 312M of the tire case 317 and forming the resin chafer 464 by pressing with the press 450 and vulcanize molding. When disposing the chafer resin material R a bonding agent is coated on the surface of the case section body 317A at the locations where the chafer resin material R is to be disposed. Displacement can accordingly be prevented of the position of the chafer resin material R when pressed with the press 450.
In the present exemplary embodiment chafer thermoplastic material is introduced to the regions A of the case section body 317A where the bead core 18 is exposed, in a similar manner to in the third exemplary embodiment. Accordingly, as shown in
The tire 310 of the third exemplary embodiment and the fourth exemplary embodiment are tires of similar structure to the tire 10 of the first exemplary embodiment, however configuration may be made with a tire of similar structure to that of the tire 210 of the second exemplary embodiment. In such cases a resin chafer 324 of the third exemplary embodiment or a resin chafer 464 of the fourth exemplary embodiment is employed in place of the seal layer 224 of the second exemplary embodiment.
In order to confirm the advantageous effects of the present invention the present inventor prepares an example of the tire 310 of the third exemplary embodiment (referred to below as the Example Tire) provided with a tire case 317 formed from an olefin thermoplastic elastomer (TPO) and a resin chafer 324, and an example of a tire not provided with a resin chafer (referred to below as a Conventional Example Tire). The present inventor then assembles these tires to rims, tests the internal pressure retaining ability and evaluates their performance. The Conventional Example Tire is a tire that differs from the Example Tire in that the resin chafer 324 is not formed.
In the test the internal pressure is measured 48 hours after the internal pressure has been inflated to 0.39 MPa (4 kg/cm2). An evaluation index is computed for relative evaluation of the Example Tire with respect to an evaluation index of 100 for the internal pressure retaining ability of the Conventional Example Tire. The larger the evaluation index the higher the performance, namely indicating superior internal pressure retaining ability. The evaluation index of the Example Tire is 105, a result indicating that the internal pressure retaining ability is better than that of the Conventional Example Tire.
Explanation follows regarding a tire and tire manufacturing method of a fifth exemplary embodiment, with reference to the drawings. As shown in
The tire 510 is equipped with a ring shaped tire case 517 (serving as an example of a tire frame member) formed from a frame resin material and configured by: a pair of bead sections 12 (see
The tire case 517 is formed from circular ring shaped case section bodies 517A (frame structuring members) each formed in the same shape such as by molding in a mold with a bead section configuring portion 512M for covering the bead core 18 of one of the bead sections 12, one of the side sections 14 and a half-width crown section 16 integrated together. The case section bodies 517A are aligned to face each other and are joined together along the tire center CL. The tire case 517 is not limited to being formed by joining together two members, and may be formed by joining together three or more members, or may be formed as a single body including the pair of bead sections 12, the pair of the side sections 14 and the crown section 16.
As shown in
The case section bodies 517A are formed from a resin material (frame resin material). A similar resin material to that employed in the first exemplary embodiment can be employed as the resin material in the present exemplary embodiment. The case section bodies 517A can be formed, for example, by vacuum molding, pressure molding, injection molding, or melt-casting. Manufacturing processes can accordingly be greatly simplified in comparison to molding (vulcanization) in rubber, and the time for molding can also be shortened. In the present exemplary embodiment the case section bodies 517A are formed with left-right symmetry, namely one of the case section bodies 517A is the same shape as the other of the case section bodies 517A. This has the advantage of allowing the case section bodies 517A to be formed with a single type of mold.
In the present exemplary embodiment the contact portion of the bead sections 12 to the rim 20, at least the portion that makes contact with the rim flange 22 of the rim 20, is formed with the circular ring shaped rubber chafer 524 formed from a rubber (vulcanized rubber) having superior sealing ability (gas sealing performance) to the frame resin material forming the tire case 517. The rubber chafer 524 may extend to the portion that contacts the bead seat section 21, and may also extend to the tire inside. A similar type of rubber to that employed on the bead section outside face of an ordinary rubber pneumatic tire is preferably employed as the rubber for forming the rubber chafer 524.
In the present exemplary embodiment, as an example, a thermoplastic material (such as for example a thermoplastic resin or a thermoplastic elastomer) is selected from resin materials as the frame resin material for forming the tire case 517.
Explanation follows regarding a manufacturing method of the tire 510 of the present exemplary embodiment. In the following explanation the case section bodies 517A are formed by injection molding (see
In the present exemplary embodiment a mold 540 is employed, as shown in
As shown in
When the contact length L of the jigs 546 to the bead core 18 along the tire circumferential direction is 15 mm or less then stress is not liable to be concentrated in the case section bodies 517A. Such an effect is more readily achieved when the length L is 5 mm or less. The contact length L is preferably 1 mm or longer from the perspective of the strength of the jigs 546.
In the present exemplary embodiment, each of the jigs 546 is formed from a magnetic member. There are 12 individual jigs 546 disposed at even intervals along the bead core housing location.
A recess portion 547 (see
As shown in
The gate 548 is a disk gate with a ring shaped opening, and the cavity S is formed as a hollow circular disk shape in communication with the ring shaped gate 548. The gate 548 may be configured as a pin gate, however a disk gate is preferable from the perspective of formability.
In the present exemplary embodiment, first the mold 540 is opened, the tire inside portion of the bead core 18 is inserted into the recess portion 547 of each of the jigs 546, and the mold 540 closed up. The bead core 18 is formed from a body with magnetic properties so as to enable magnetic attachment.
Melted frame resin material is then poured into the mold 540 from the gate 548, and the case section body 517A is formed by injection molding.
During pouring the frame resin material is poured from the gate 548 through between the bead core 18 and the outer mold 542 at the positions where the jigs 546 are provided, and so the bead core 18 is pressed from the tire outside towards the tire inside. The moving force bearing on the bead core 18 can accordingly be sufficiently supported by the jigs 546. It is thus possible to pour the melted frame resin material with the jigs 546, for preventing displacement of the bead core 18, in a state in which there is no contact of the jigs 546 to the bead core 18 from the tire outside.
The case section body 517A manufactured with the bead core 18 held in this manner is then removed from the mold 540, and as shown in
A rubber chafer molding face 556 is formed on the upper mold 552, the case section body 517A is set in the lower mold 551, and a specific dimension of green rubber R for forming a rubber chafer 524 is placed in a bead section configuring portion 512M of the case section body 517A. When the upper mold 552 is lowered and the molding face (bottom face) of the upper mold 552 is pressed against the side section 14 of the case section body 517A a space is formed between the upper mold 552 and the bead section configuring portion 512M enabling a rubber chafer of a set shape to be vulcanize molded. A spew molding through hole 558 is also formed in the upper mold 552.
In the present exemplary embodiment, the case section body 517A and the green rubber R are set in the lower mold 551. The upper mold 552 is lowered to a set position and the green rubber R pressed, and the green rubber R vulcanize molded by subjecting the green rubber R to a specific temperature for a specific duration. As a result the rubber chafer 524 formed from a vulcanized rubber is formed (see
Preferably sulfur or peroxide is employed as a vulcanization promoting agent for the green rubber R. Preferably carbon black or particularly preferably silica is employed as a reinforcing agent contained in the green rubber R. An amino silane or a polysulfide may also be employed as a coupling agent for the green rubber R.
When disposing the green rubber R in the present exemplary embodiment, the green rubber R is placed at locations to cover the regions A referred to above when the green rubber R is pressed by the press 550. Configuration may be made in which a single or double layered bonding agent layer is coated on the surface of the case section body 517A at the positions where the green rubber R is to be set. The bonding force is raised in such cases by buffing abrasion such as with sandpaper to the surface at the locations to be coated with the bonding agent. Preferably a certain amount of drying is performed after coating the bonding agent in order to raise the bonding force. Accordingly coating the bonding agent is preferably performed in an atmosphere with a relative humidity of 70% or less. The bonding agent here may, for example, be a triazine thiol bonding agent, a chlorinated rubber bonding agent, a phenol resin bonding agent, an isocyanate bonding agent, or a halogenated rubber bonding agent without particular limitation.
Then the two case section bodies 517A are joined together using a method for joining the case section bodies 17A of the first exemplary embodiment so as to produce the tire case 517.
Forming the rubber chafer 524 may be performed after joining together the case section bodies 517A, and it is possible to change the sequence of processes as appropriate.
The tire case 517 is then formed with the reinforcement layer 28, the covering layer 29 and the tread 30 by methods similar to those of the first exemplary embodiment. This completes production of the tire 510 (see
In the present exemplary embodiment, as explained above, the rubber chafer 524 is formed by vulcanize molding onto the bead section configuring portion 512M of the case section body 517A formed from the frame resin material. The rubber chafer 524 accordingly makes contact with a rim when the tire is assembled to a rim, and so air is not liable to come out from between the bead section and the rim even when air is filled in the tire 510. High internal pressure retaining ability is accordingly achieved even though the tire case 517 is formed from a resin material (the frame resin material).
The side sections 14 and the tread section (the crown section 16) are also formed to the tire case 517 and the two case section bodies 517A are joined together along the tire center CL using a welding thermoplastic material (not shown in the drawings). Tire strength is accordingly efficiently raised.
The rubber chafer 524 also extends to the tire inside (tire inside face) of the bead sections 12. There is accordingly less concern of the edge of the rubber chafer 524 peeling away during rim assembly than for cases in which the rubber chafer 524 is only provided to the tire outside of the bead sections 12.
A reduction in the manufacturing time is achieved by disposing the green rubber R on the bead section configuring portion 512M of the tire case 517 and forming the rubber chafer 524 by pressing with the press 550 and vulcanize molding.
When the case section bodies 517A are manufactured melted frame resin material is poured into the cavity with the bead core 18 in a contact state with the jigs 546 from the direction that will be at the tire inside. Namely, it is thus possible to pour the melted frame resin material with the jigs 546, for preventing displacement of the bead core 18, in a state in which the jigs 546 do not contact the bead core 18 from the tire outside. Accordingly the regions A, where the jigs 546 were in contact with the bead core 18 such that there is no frame resin material present and the bead core 18 is exposed, are not formed at all on the tire outside of the case section bodies 517A. There is accordingly frame resin material present spanning across every location that will make contact with the rim 20, facilitating securing sufficient air retention ability when assembled to a rim.
The locations where the green rubber R is disposed are locations where the green rubber R will cover the regions A referred to above when the green rubber R is pressed by the press 550. Accordingly, the regions A are covered by the rubber chafer 524, and so rusting of the metal bead core 18 can be prevented and also deterioration of the case section body 517A and damage nucleation in the case section body 517A are prevented from occurring. When disposing the green rubber R a bonding agent is coated on the surface of the case section body 517A at the locations where the green rubber R is to be disposed.
Displacement of the position of the green rubber R can accordingly be prevented when pressed with the press 550, and the bonding force is raised between the rubber chafer 524 and the case section body 517A.
There are regions A formed at the tire inside of the case section bodies 517A where the jigs 546 were in contact with the bead core 18 such that there is no solidified frame resin material present and the bead core 18 is exposed. However, air retention ability can be maintained when assembled to a rim even with a relatively large dimension for the regions A. Jig dimensions and shape are accordingly achieved capable of securing sufficient ability to prevent rupturing of the frame resin material at the periphery of the bead core during knocking out, and also capable of sufficiently suppressing displacement of the bead core 18 during tire molding. Not only is displacement of the bead core 18 suppressed but deformation of the bead core 18 due to pressure applied thereto during molding can also be prevented.
Such an advantageous effect is obtained even when high pressure pouring is employed for injection molding when pouring the melted frame resin material.
The bead core 18 is readily retained by the jigs 546 since the jigs 546 are formed from magnets in the present exemplary embodiment. Configuration may be made employing a jig that is covered with a shielding member to stop magnetic force being dissipated in directions other than the direction of the bead core 18. The jigs 546 are disposed at plural locations along the bead core housing location. The positioning precision of the bead core 18 can accordingly be further raised.
When pouring the frame resin material the frame resin material is poured between the bead core 18 and the outer mold 542 for molding the tire outside. The bead core 18 is accordingly pressed from the tire outside towards the tire inside during pouring. The movement force bearing on the bead core 18 can accordingly be sufficiently supported with the jigs 546.
Configuration may be made to change the profile of the molding face of the upper mold 552 such that the rubber chafer 524 is formed to extend along the side sections 14. A pneumatic tire is accordingly easily achieved capable of preventing damage to the side sections 14, such as from curbs.
In order to further prevent displacement of the bead core 18 configuration may be made with an auxiliary jig 562 provided that has a variable setting position in the direction of intruding-retracting in the cavity S, as shown in
Reinforcement materials (such as fibers, cords, non-woven fabric or woven fabric made of a high polymer material or a metal) may be embedded in locations of the tire case 517 other than in the crown section (such as in the side sections 14).
After the case section body 517A has been molded it is also possible to leave the case section body 517A disposed in the inner mold 544 and only remove the outer mold 542. The rubber chafer 524 is then formed by placing the green rubber R, and vulcanize molding by pressing the green rubber R with an outer mold with a similar profile on the green rubber pressing face to that of the upper mold 552.
The joining faces of the bead section configuring portion 512M and the rubber chafer 524 may be profiled with recesses and projections to obtain an anchor effect (strong meshing effect, like that of dropping an anchor) in order to raise the joint strength between the bead section configuring portions 512M of the case section bodies 517A and the rubber chafers 524.
For example, a bead section configuring portion may be employed that is arrayed with inverted truncated circular conical shaped projections whose diameter is larger on the rubber chafer side than on the base side. An anchor effect is obtained by a bead section configuring portion with simple recesses and projections on the rubber chafer 524 side, and also by a bead section configuring portion with recesses of curved cross-sectional profile on the rubber chafer 524 side.
The depth of the recesses and projections for obtaining such an anchor effect is preferably 2 mm or less, and more preferably 1 mm or less. A dropping off in the strength of the molded item might conceivably occur with a depth of greater than 2 mm. However, it is difficult to obtain sufficient anchor effect when the depth of recesses and projections is less than 0.05 mm. The molding face of a mold may be pre-formed with a corresponding recessed and projected profile in order to form such a recessed and projected profile.
Explanation follows regarding a tire manufacturing method of a sixth exemplary embodiment. In the present exemplary embodiment, as shown in
In the present exemplary embodiment the case section body 517A is housed in the injection molding mold 570, the mold 570 closed, and then the chafer green rubber injected from the gate 578 and vulcanize molding performed. The rubber chafer 584 is accordingly formed to the case section body 517A, as shown in
A similar method to that of the fifth exemplary embodiment is then employed to join together the two case section bodies 517A, forming the tire case 517. Then the reinforcement layer 28, the covering layer 29 and the tread 30 are formed on the tire case 517, thus completing manufacture of the tire 510.
Thus in the present exemplary embodiment the rubber chafer 584 is formed by injecting green rubber onto the bead section configuring portion 512M of the case section body 517A formed from frame resin material, and performing vulcanize molding. The rubber chafer 584 accordingly makes rim contact when the tire is assembled to the rim, and air is not liable to escape from between the bead sections and the rim even when air is filled in the tire 510. There is accordingly high internal pressure retaining ability even though the tire case 517 is formed from a resin material.
Similarly to in the fifth exemplary embodiment, green rubber is inserted in the present exemplary embodiment at the regions A where the bead core 18 of the case section bodies 517A is exposed. Accordingly, as shown in
Configuration may be made in which a single or double layered bonding agent layer is coated on the surface of the case section bodies 517A at positions where the rubber chafer 584 is to be disposed. In such cases, similarly to in the fifth exemplary embodiment, the bonding force is raised in such cases by buffing abrasion such as with sandpaper to the surface at the locations to be coated with the bonding agent. The bonding agent may be a triazine thiol bonding agent, a chlorinated rubber bonding agent, a phenol resin bonding agent, an isocyanate bonding agent, or a halogenated rubber bonding agent, without particular limitation.
In the present exemplary embodiment explanation has been given of a case in which green rubber is poured into the injection molding mold 570, however a rubber chafer 524 may be formed by employing the press 550 explained in the fifth exemplary embodiment, and injecting and vulcanize molding by pouring green rubber in through a through hole 558 instead of placing green rubber R. In such cases the regions A referred to above are also covered by the green rubber R, and as a result it is possible to achieve a structure in which the rubber chafer 524 covers the regions A. By adopting such an approach rusting of the metal bead core 18 can be prevented and also deterioration of the case section body 517A and damage nucleation in the case section body 517A can be prevented from occurring.
Configuration may also be made, as shown in
The tires 510 of the fifth exemplary embodiment and the sixth exemplary embodiment are tires of similar structure to the tire 10 of the first exemplary embodiment, however configuration may be made with a tire of similar structure to that of the tire 210 of the second exemplary embodiment. In such cases a rubber chafer 524 of the fifth exemplary embodiment or a rubber chafer 584 of the sixth exemplary embodiment is employed in place of the seal layer 224 of the second exemplary embodiment.
In order to confirm the advantageous effects of the present invention the present inventor prepares an example of the tire 510 of the fifth exemplary embodiment (referred to below as the Example Tire) provided with a tire case 517 formed from an olefin thermoplastic elastomer (TPO) and a rubber chafer 524, and an example of a tire not provided with a rubber chafer (referred to below as a Conventional Example Tire). The present inventor then assembles these tires to rims, tests the internal pressure retaining ability and evaluates their performance. The Conventional Example Tire is a tire that differs from the Example Tire in that the rubber chafer 524 is not formed.
In the test the internal pressure is measured 48 hours after the internal pressure has been inflated to 0.39 MPa (4 kg/cm2). An evaluation index is computed for relative evaluation of the Example Tire with respect to an evaluation index of 100 for the internal pressure retaining ability of the Conventional Example Tire. The larger the evaluation index the higher the performance, namely indicating superior internal pressure retaining ability. The evaluation index of the Example Tire is 110, a result indicating that the internal pressure retaining ability is better than that of the Conventional Example Tire.
Note that while embodiments of the present invention have been explained by way of exemplary embodiments, these are merely examples and various modifications may be implemented within a scope not departing from the spirit of the present invention. Obviously the scope of rights of the present invention are not limited by the exemplary embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-191229 | Aug 2009 | JP | national |
| 2009-191230 | Aug 2009 | JP | national |
| 2009-191231 | Aug 2009 | JP | national |
| 2009-191232 | Aug 2009 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP10/64115 | 8/20/2010 | WO | 00 | 2/21/2012 |
