Patent Application
20210146735
This disclosure relates to a tire and a method of fixing a porous body.
Conventionally, there is known a tire that reduces road noise by adhering a porous body such as sound absorbing sponge to a tire inner surface to absorb cavity resonance energy. JP 4318639 B (PTL 1) describes a tire of this type.
PTL 1: JP 4318639 B
It has been known that, in order to improve the release properties from a bladder that is in close contact during the vulcanizing and molding of a tire, a release agent such as silicone or mica is previously applied to a tire inner surface of a raw tire or an outer surface of the bladder before the vulcanization and molding. The release agent remains on the tire inner surface after the vulcanization and molding. Therefore, when a porous body is adhered to the tire inner surface, for example, the release agent on the tire inner surface inhibits the bonding of the porous body and the tire inner surface.
The release agent can be removed from the tire inner surface by, for example, baking with laser irradiation or washing with a detergent before adhering the porous body. However, there is a demand for a structure in which a porous body can be adhered without removing the release agent.
It could thus be helpful to provide a tire having an adhesion structure in which a porous body can be fixed to a tire inner surface without removing a release agent from the tire inner surface, and a method of fixing a porous body.
The tire of a first aspect of the present disclosure includes an inner surface layer that forms a tire inner surface and is formed of a thermoplastic resin or contains a thermoplastic resin, and a porous body that is partially embedded in the inner surface layer.
The method of fixing a porous body of a second aspect of the present disclosure includes melting an inner surface layer, where the inner surface layer forms a tire inner surface and is formed of a thermoplastic resin or contains a thermoplastic resin, and pressing a porous body to embed the porous body in the inner surface layer.
According to the present disclosure, it is possible to provide a tire having an adhesion structure in which a porous body can be fixed to a tire inner surface without removing a release agent from the tire inner surface, and a method of fixing a porous body.
In the accompanying drawings:
The following describes the tire and the method of fixing a porous body of the present disclosure with reference to
As illustrated in
As will be described later, although the tire 1 of the present embodiment is a tubeless type radial tire for passenger vehicles, it is not limited to this structure. For example, it may be a tire including a tire frame made of resin containing at least 50 mass % or more, preferably 90 mass % or more of a resin material such as a thermoplastic resin, a thermoplastic elastomer, or a thermosetting resin. In the case of such a tire including a tire frame made of resin, the above-described inner surface layer 11 may be formed by the tire frame itself. However, it is not limited to this structure, and the inner surface layer 11 may be formed by laminating another layer on the tire frame.
The inner surface layer 11 is not limited to the case of being formed of a thermoplastic resin. For example, it may have a composition in which a thermoplastic resin is partly contained, such as a composition in which a thermoplastic resin is mixed with rubber. In the case where the inner surface layer 11 has a composition in which a thermoplastic resin is partly contained, it preferably contains at least 50 mass % or more of a thermoplastic resin.
The material of the resin of which the inner surface layer 11 is formed or the resin contained in the inner surface layer 11 may contain polypropylene, polyethylene, polystyrene, AS resin, ABS resin, vinyl chloride resin, PA (6, 6-6, 6-10, 6-12, 12), or polyester.
The porous body 3 may be formed of, for example, a sponge material having open cells or closed cells obtained by foaming rubber or a synthetic resin. The porous body 3 of the present embodiment is formed of a sponge material. The material of the sponge material is preferably synthetic resin sponge such as ether-based polyurethane sponge, ester-based polyurethane sponge, and polyethylene sponge; or rubber sponge such as chloroprene rubber sponge (CR sponge), ethylene propylene rubber sponge (EDPM sponge), and nitrile rubber sponge (NBR sponge). In particular, it is preferably, for example, polyurethane-based or polyethylene-based ones including ether-based polyurethane sponge from the viewpoints of sound controlling, lightness, controllability of foaming, durability, and the like.
In addition, the porous body 3 may be formed of nonwoven fabrics. In the case where the porous body 3 is formed of nonwoven fabrics, it may be, for example, formed by intertwining animal fibers, plant fibers, mineral fibers, synthetic fibers, metal fibers, glass fibers, or the like. Examples of the material of the synthetic fibers include, for example, aromatic polyamide, polyamide, polyester, polyolefin, modacryl, and combinations thereof.
The porous body 3 may be formed by weaving animal fibers, plant fibers, mineral fibers, synthetic fibers, metal fibers, glass fibers, or the like.
The density of the porous body 3 may be set in the range of 16 kg/m3 to 100 kg/m3, for example. The hardness of the porous body 3 may be set in the range of 20 N to 300 N, for example. Note that the hardness means hardness measured based on the “Method D” specified in “Type of Test” of JIS K6400-2 cited in JIS K6401 (the 2011 edition). Further, the tensile strength of the porous body 3 may be set in the range of 50 kPa to 300 kPa, for example.
The porous body 3 can absorb sound by converting the vibration energy of vibrating air into heat energy through the voids formed on the surface or the inside of the porous body 3. As a result, it is possible to reduce cavity resonance noise generated in the tire 1 assembled with a rim.
As described above, the tire 1 includes an inner surface layer 11 that is formed of a thermoplastic resin or contains a thermoplastic resin, where the inner surface layer 11 forms the tire inner surface 30. Further, in the tire 1, a part of the porous body 3 is embedded in the inner surface layer 11, and the porous body 3 is fixed to the inner surface layer 11 in this way. With such an adhesion structure, it is possible to fix the porous body 3 to the tire inner surface 30 regardless of whether or not a release agent is removed from the tire inner surface 30, that is, it is possible to fix the porous body 3 to the tire inner surface 30 even without removing a release agent from the tire inner surface 30.
The following describes the tire 1 of the present embodiment in detail.
<Tire Body 2>
First, the tire body 2 of the tire 1 of the present embodiment will be described. As illustrated in
More specifically, the tire body 2 of the present embodiment includes a bead member 4, a carcass 5, a belt 6, tread rubber 7, side rubber 8, an inner liner 9, and an inner surface member 10.
[Bead member 4] The bead member 4 is embedded in the bead portion 2c. The bead member 4 includes a bead core 4a and a bead filler 4b made of rubber located on the outside of the tire radial direction B with respect to the bead core 4a. The bead core 4a includes a plurality of bead wires whose periphery is covered with rubber. The bead wires are formed of steel cords. The steel cords may be formed of, for example, steel monofilaments or stranded wires.
Organic fibers, carbon fibers, or the like may also be used as the bead wires.
[Carcass 5]
The carcass 5 straddles between the pair of bead portions 2c, more specifically between the bead cores 4a of the pair of bead members 4, and extends in a toroidal shape. The carcass 5 has at least a radial structure.
Further, the carcass 5 is constituted by one or more carcass plies 5a (one in the present embodiment) in which carcass cords are arranged at an angle of, for example, 75 degrees to 90 degrees with respect to a tire circumferential direction C. The carcass ply 5a includes a ply main body located between the pair of bead cores 4a, and ply folded portions that are folded from the inside to the outside in the tire width direction A around the bead cores 4a at the two ends of the ply main body. Then, the bead filler 4b that extends in a tapered shape from the bead core 4a to the outside in the tire radial direction B is disposed between the ply main body and the ply folded portion. In the present embodiment, the carcass cords constituting the carcass ply 5a are polyester cords. However, other cords such as organic fiber cords, like nylon, rayon and aramid, and steel cords if necessary, may be used. Further, the number of the carcass plies 5a may be two or more.
[Belt 6]
The belt 6 includes one or more belt layers (five in the present embodiment) arranged outside the crown portion of the carcass 5 in the tire radial direction B. Specifically, the belt 6 of the present embodiment includes an inclined belt 6a and a circumferential belt 6b, as illustrated in
As illustrated in
As illustrated in
[Tread Rubber 7 and Side Rubber 8]
The tread rubber 7 constitutes an outer surface of the tread portion 2a in the tire radial direction B, and a tread pattern including, for example, a circumferential groove 7a extending in the tire circumferential direction C and a width direction groove (not illustrated in the drawings) extending in the tire width direction A is formed on the outer surface of the tread. The side rubber 8 constitutes an outer surface of the side wall portion 2b in the tire width direction A and is formed integrally with the above-described tread rubber 7.
[Inner Liner 9]
The inner liner 9 is laminated on the inner surface of the carcass 5 and is formed of butyl-based rubber having low air permeability. That is, the inner liner 9 forms a rubber layer 12 laminated on the inner surface of the carcass 5. Note that the butyl-based rubber means butyl rubber and halogenated butyl rubber which is a derivative thereof.
[Inner Surface Member 10]
The inner surface member 10 is laminated on the inner surface of the inner liner 9, which is the rubber layer 12, and forms the tire inner surface 30. That is, the inner surface layer 11 of the present embodiment is formed by the inner surface member 10.
The tire body 2 is vulcanized and molded with the inner surface member 10 laminated on the inner surface of the inner liner 9. Therefore, in order to improve the release properties from a bladder that is in close contact during the vulcanization and molding, the tire inner surface 30, that is, the surface of the inner surface member 10 on the opposite side of the inner liner 9, is previously applied with a release agent such as silicon before the vulcanization and molding.
Because the porous body 3 is fixed to the inner surface member 10 forming the inner surface layer 11 with the release agent S interposed between the inner surface member 10 and the porous body 3, the release agent S serves as a film, and the inner surface layer 11 is less likely to come into contact with oxygen that permeates the porous body 3. That is, the exposure of the inner surface layer 11 to oxygen can be suppressed, and the deterioration of the inner surface layer 11 due to oxygen can be suppressed. The details of the method of fixing the porous body 3 will be described later (see
The inner surface member 10 of the present embodiment is formed of a thermoplastic resin or contains a thermoplastic resin. In addition, the inner surface member 10 of the present embodiment can be formed of the material of the inner surface layer 11 described above. The porous body 3 is fixed to the inner surface member 10 with a part of the porous body 3 embedded in the inner surface member 10 forming the inner surface layer 11. The details of the method of fixing the porous body 3 to the inner surface member 10 will be described later (see
The thickness of the inner surface member 10 is not particularly limited as long as it has a thickness in which a part of the porous body 3 can be embedded. For example, the thickness may be 3 μm or more.
<Porous Body 3>
As illustrated in
The porous body 3 is not particularly limited as long as it is partially embedded in the inner surface layer 11 forming the tire inner surface 30. However, in the case of using the method of utilizing ultrasonic waves to fix the porous body 3 to the inner surface member 10 described later (see FIGS. 4A to 4C), the porous body 3 preferably has flexibility. In addition, in the case of using the method of utilizing ultrasonic waves to fix the porous body 3 to the inner surface member 10 described later (see
In addition, the melting point of the porous body 3 is preferably higher than the melting point of the inner surface layer 11 formed by the inner surface member 10 in the present embodiment. In this way, it is easy to embed a part of the porous body 3 in the inner surface layer 11 when the inner surface layer 11 formed by the inner surface member 10 is in a molten state, which is not limited to the fixing method utilizing ultrasonic waves (see
Further, on the basis of the above-described magnitude relationship of melting points, the porous body 3 preferably has a structure where the temperature of the decomposition point is lower than the temperature of the melting point and the temperature of the decomposition point is higher than the temperature of the melting point of the inner surface layer 11. The “decomposition point” means the temperature at which thermal decomposition occurs. With such a structure, the porous body 3 is embedded in and fixed to the inner surface layer 11 at a temperature that is lower than the temperature of the decomposition point of the porous body 3. In this way, it is possible to embed a part of the porous body 3 in the inner surface layer 11 when the inner surface layer 11 formed by the inner surface member 10 is in a molten state while the porous body 3 is not melted, which is not limited to the fixing method utilizing ultrasonic waves (see
However, on the basis of the above-described magnitude relationship of melting points, the porous body 3 may have a structure where the temperature of the melting point is lower than the temperature of the decomposition point. With such a structure, the porous body 3 is embedded in and fixed to the inner surface layer 11 at a temperature that is equal to or higher than the temperature of the melting point of the porous body 3 and lower than the temperature of the decomposition point of the porous body 3. In this way, it is possible to embed a part of the porous body 3 in the inner surface layer 11 when the inner surface layer 11 formed by the inner surface member 10 is in a molten state and to melt the same part or another part of the porous body 3 to mix or weld it with the molten inner surface layer 11, which is not limited to the fixing method utilizing ultrasonic waves (see
As described above, it does not matter whether or not the porous body 3 is in a molten state during the fixing if a part of the porous body 3 is embedded in the inner surface layer 11 formed by the inner surface member 10.
Next, a method of fixing a porous body 3 of an embodiment of the present disclosure will be described.
The inner surface layer 11 is laminated on the inner liner 9 that is the rubber layer 12. The vibration energy of ultrasonic waves does not melt the rubber layer 12. Providing such a rubber layer 12 can suppress the melting of each portion on the opposite side of the inner surface layer 11 with the rubber layer 12 in between.
As described above, since the porous body 3 is fixed to the inner surface layer 11 with a part of the porous body 3 embedded in the inner surface layer 11, the porous body 3 can be fixed to the inner surface layer 11 regardless of whether or not the release agent S is adhered to the tire inner surface 30 formed by the inner surface layer 11.
In order to realize the ultrasonic welding according to
In the case where the porous body 3 is not flexible, it is acceptable if the thickness of the porous body 3 is small. However, in the case of a porous body 3 of small thickness, the functions required for the porous body 3 such as sound absorbing performance may deteriorate. In the case where the porous body 3 is not flexible and the thickness of the porous body 3 is large, it is necessary to increase the intensity of the ultrasonic waves emitted from the ultrasonic horn 50, so that a versatile ultrasonic welding machine may not be used. For the above reasons, it is particularly preferable to use a porous body 3 having flexibility.
Further, in order to perform the ultrasonic welding according to
The density of the porous body 3 may be set, for example, in the range of 16 kg/m3 to 100 kg/m3 as described above. The density of the porous body 3 is preferably set within the above range so as to be lower than the density of the inner surface layer 11.
Further, in order to perform the ultrasonic welding according to
The material of the porous body 3 may be, for example, a material having a melting point in the range of 100° C. to 260° C. The material of the inner surface member 10 forming the inner surface layer 11 may be, for example, a material having a melting point in the range of 80° C. to 240° C. The melting point of the porous body 3 is preferably set to be higher than the melting point of the inner surface layer 11 within these ranges.
As described above, the method of fixing a porous body 3 illustrated in
The ultrasonic welding machine used in the fixing method illustrated in
In addition, the porous body 3 of the present embodiment is formed of a sponge material as illustrated in
When the heat-resistant filter described above is used as the porous body 3, the ultrasonic wave irradiation width may be 0.3 mm and the ultrasonic wave irradiation length may be 25 mm or 50 mm in order to realize desired embedding in the inner surface layer 11. The ultrasonic wave irradiation length is preferably 25 mm.
The tire and the method of fixing a porous body of the present disclosure are not limited to the specific structures and steps described in the above embodiment, and modifications and changes can be made without departing from the scope of the claims. For example, in the example illustrated in
The numbers of the inclined belt layers and the circumferential belt layers in the belt 6 of the tire 1 are not limited to the numbers described in the above embodiment. Further, the lengths of the inclined belt layer and the circumferential belt layer in the tire width direction A, and the positional relationship between the two ends of the inclined belt layer and the circumferential belt layer in the tire width direction A are not limited to the lengths and positional relationship described in the above embodiment.
The present disclosure relates to a tire and a method of fixing a porous body.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-242064 | Dec 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/045360 | 12/10/2018 | WO | 00 |
