The present disclosure relates generally to the field of semi-pneumatic tires. More specifically, and without limitation, this disclosure relates to multi-core semi-pneumatic tires and methods for forming the same. The tires and formation techniques disclosed herein may be used in various applications and systems, such as lawnmowers, automotive vehicles, and other systems that benefit from semi-pneumatic tires.
Semi-pneumatic tires typically comprise rubber surrounding a hollow core filled with air. The hollow core is an empty chamber that is intentionally formed within the body of the tire when it is manufactured and is not further pressurized with air. Unlike pneumatic tires, the hollow core is sealed during vulcanization and does not include any valves or bladders for refilling air in the core. Nevertheless, the hollow core is generally small enough such that the tire may continue to be used for a period of time after the tire has been punctured, e.g., before the tire needs to be replaced due to any shape deformity caused by continued use of the punctured tire. Accordingly, semi-pneumatic tires are often referred to as “run-flat” tires.
Existing constructions of semi-pneumatic tires are generally limited in size to widths (e.g., sidewall to sidewall) of 6.5 inches or less. One solution to this problem developed by Michelin® is an airless tire, marketed as a Tweel®, comprising a hub connected to the rim via flexible polyurethane spokes. Michelin's Tweel tires, however, are generally more costly than other conventional semi-pneumatic tires and are not cost-effective for applications such as industrial mowing or other high-mileage uses.
Embodiments of the present disclosure overcome the disadvantages of the prior art by providing multi-core semi-pneumatic tires and methods for forming such semi-pneumatic tires. By including multiple cores, the semi-pneumatic tires of the present disclosure may exceed the size limitations of existing semi-pneumatic tires, for example, having sizes up to or exceeding approximately 6.5 inch widths for tires with two hollow cores and even larger diameters for semi-pneumatic tires having more than two cores, such as up to or exceeding approximately 12 inch widths, 26 inch widths, or greater. The multi-core semi-pneumatic tires of the present disclosure are also more cost-effective compared with existing airless tires, such as the Tweel®.
Further, embodiments of the present disclosure provide methods for manufacturing multi-core semi-pneumatic tires. For example, by extruding rubber to form multiple hollow cores within the body of a semi-pneumatic tire, embodiments of the present disclosure can reduce the manufacturing time and costs compared with traditional semi-pneumatic tire-manufacturing processes. In some exemplary embodiments, the semi-pneumatic tire is constructed comprising two or more continuous hollow cores that extend in parallel around substantially the entire length of the tire's circumference. In such exemplary embodiments, adjacent parallel cores may be separated from each other within the tire by one or more rubber walls formed by the extruding process. Further to these exemplary embodiments, a method for manufacturing such a multi-core semi-pneumatic tire is also provided.
Additional objects and advantages of the present disclosure will be set forth in part in the following detailed description, and in part will be obvious from the description, or may be learned by practice of the present disclosure. The objects and advantages of the present disclosure will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the disclosed embodiments.
The accompanying drawings, which comprise a part of this specification, illustrate several embodiments and, together with the description, serve to explain the principles and features of the disclosed embodiments. In the drawings:
The disclosed embodiments provide multi-core semi-pneumatic tires and methods for manufacturing the same. Advantageously, the exemplary embodiments disclose semi-pneumatic tire designs and manufacturing processes that can be more cost-effective for producing larger-width semi-pneumatic tires than is conventionally possible, such as tires with widths greater than 26 inches, or greater than 12 inches or at least greater than 6.5 inches. Embodiments of the present disclosure may be implemented and used in various applications and systems, such as but not limited to lawnmowers, automotive vehicles, golf carts, powersport vehicles, and any other vehicles or systems that may benefit from semi-pneumatic tires. Although exemplary embodiments of the present disclosure are generally described with reference to a single tire, it will be appreciated that the multi-core semi-pneumatic tires described in this disclosure may be part of, or integrated with, a larger assembly, such as containing at least one wheel, axel, or other component of a vehicle.
According to an aspect of the present disclosure, a semi-pneumatic tire may comprise a plurality of cores. In the exemplary embodiments, a “core” may refer to a hollow volume that extends along a circumferential direction of the tire. For example, a core may encompass the whole circumference of the tire. Also, as disclosed in the exemplary embodiments, the cores may be provided in any suitable size and shape for the tire. The multi-core tires of the exemplary embodiments are “semi-pneumatic” because each of their plurality of cores does not include any valves or other mechanisms for inserting pressurized air into the cores. Accordingly, the cores of the tires may be sealed from an environment external to the tire.
Additionally, in some embodiments, each core in the multi-core tire may be insulated from one or more adjacent cores by a material, such as rubber or a rubber-like material, that preferably may be formed within the body of the tire using an extruding process. For example, the same material that is used to form the outer portions and/or bulk of the tire also may be used to form one or more walls, partitions, diaphragms, or other separators between adjacent cores within the tire. In some embodiments, the material used to form the tire and its internal separators between adjacent cores preferably comprises any natural or synthetic rubber, including but not limited to isoprene polymers, chloroprene polymers, isobutylene polymers, styrene polymers, butadiene polymers, or any combination thereof. Accordingly, as used herein, the term “rubber-like” material refers to any natural or synthetic rubber material, including but not limited to the examples above.
According to another aspect of the present disclosure, a method for forming a semi-pneumatic tire using an extrusion process is described. For example, the method may include extruding a material, such as a rubber-like material, through a mold. In some exemplary embodiments, the mold preferably is shaped having a circular cross-section, where “circular” in this context may refer to a circle, an oval, an ellipse, or any other geometry with one or more rounded corners. The circular shape of the mold may enable the cross-section of the tire to be formed by extruding a rubber-like material through the mold. The extruded material may comprise a strip or other linear shape after it is extruded. In accordance with some embodiments, the extruded material may include a plurality of hollow volumes along its length for forming multiple cores when the strip or linearly shaped extruded material is further formed into a generally circular tire configuration.
To provide the multiple cores within the tire, in some embodiments the method may include inserting a plurality of hollow sections within the cross-section of the extruded material using a plurality of mandrels. Additionally or alternatively, the mold may include a plurality of mandrels held in place with legs or other supports. In any such embodiments, the extruded rubber-like material may include a plurality of hollow cores corresponding to the positioning of the plurality of mandrels. For example, if the extruded rubber-like material comprises a strip or other linear shape after extrusion, the hollow cores may extend along a length of the strip.
In embodiments where the extruded rubber-like material includes small gaps or holes corresponding to the positions of legs or other supports in the mold that impinge into the extruded material, the method may further include vulcanizing the extruded rubber-like material to seal such gaps or holes. For example, the material may be vulcanized using heat and/or chemicals such as sulfur.
In any of the exemplary embodiments described above, the manufacturing method may further include sealing the distal ends of the extruded rubber-like material together to form a circular shaped tire in which each of the plurality of hollow cores extends along a circumference of the tire. The process of sealing the ends of the extruded material together to form the tire also may comprise a vulcanization process using heat and/or chemicals such as sulfur. In some exemplary embodiments, the vulcanization process used to seal the distal ends of the extruded material together to form a circular shaped tire may employ the same vulcanization process that is also used to seal small gaps in the extruded material, as described above, or may employ a different vulcanization process.
Additionally or alternatively, sealing the distal ends of the extruded material to form the circular tire configuration may comprise using one or more adhesives. For example, one or more rubber-based adhesives may seal the distal ends together, either permanently or before vulcanization.
Cores 107a and 107b may comprise residual air that has been trapped in each core during the manufacturing process of forming the tire 100, e.g., using one or more of the exemplary manufacturing processes of
Moreover, cores 107a and 107b may comprise irregular shapes, for example, to fit the shape of a particular wheel. For example, as
In the example of
Additionally or alternatively, as shown in
Although not depicted in
In other embodiments (not shown in
As an alternative to the use of a fixed or floating mandrel 305, some embodiments may incorporate the mandrel 305 into the mold 301 using legs or other supports. These legs or supports may result in small gaps or hollow spaces in the extruded rubber-like material 303 such that the hollow core formed by the mandrel 305 may not be sealed. Accordingly, to form a semi-pneumatic tire with a sealed core, any small gaps that may have been formed by the legs in the extrusion process may be closed using a vulcanization process, e.g., as discussed with respect to
Although described with respect to a single core, the techniques shown in
As discussed above, the process of joining the ends 351a and 351b together may include use of one or more adhesives, such as rubber-based adhesives, optionally also using a vulcanization process using heat and/or chemicals such as sulfur. Although not depicted in
In the example of
Additionally or alternatively, as shown in
Although not depicted in
In the example of
Additionally or alternatively, as shown in
Although not depicted in
Although
Any of the semi-pneumatic tires described herein may be formed according to suitable manufacturing processes. For example,
In some embodiments, the rubber-like material used in the extrusion process of step 501 may comprise any natural or synthetic rubber. For example, the rubber-like material may comprise one or more of isoprene polymers, chloroprene polymers, isobutylene polymers, styrene polymers, or butadiene polymers. In some embodiments, the rubber-like material may comprise monomers of isoprene, chloroprene, isobutylene, styrene, and/or butadiene that are polymerized (and/or co-polymerized) during vulcanization, e.g., in step 505 of method 500.
At step 503, method 500 may include creating a plurality of hollow cores within a cross-section of the extruded rubber-like material using a plurality of mandrels. Each mandrel may be used to form a respective hollow core. For example, as depicted in
In other embodiments, a plurality of mandrels in a slot of a dummy block used for the extrusion of the rubber-like material may form the plurality of hollow sections during extrusion. Accordingly, in such embodiments, step 503 may include aligning floating mandrels on the dummy block along desired locations for the plurality of hollow sections on the rubber-like material and controlling the floating mandrels independently of a ram moving the dummy block.
In some exemplary embodiments, method 500 may further include piercing the extruded rubber-like material before inserting the plurality of mandrels. The piercing may be performed using a separate device or apparatus. Those skilled in the art will also appreciate that the mandrels may be replaced with any other suitable component that may be used to create the hollow cores in the extruded rubber-like material in accordance with the exemplary embodiments herein.
At step 505, method 500 may include wrapping the extruded strip of rubber-like material around a circular mold or wheel, aligning the distal ends of the strip, including for example the hollow cores formed in the extruded material, and joining the distal ends together to form a circular shaped tire with multiple cores. In this manner, each of the plurality of hollow cores in the extruded material may extend along a circumference of the circular tire. For example, as described with reference to
The exemplary method 500 also may include additional steps. For example, in some embodiments, method 500 may include inspecting the tire, e.g., using x-rays, magnetic resonance imaging (MRI), or the like. Additionally or alternatively, method 500 may include performing one or more mechanical tests on the tire, such as stress tests, tread tests, road tests, or the like.
At step 601, method 600 may include extruding a rubber-like material through a mold. The mold may be shaped with a circular cross-section, e.g., such as the exemplary cross-sections of the tire 200 of
In some embodiments, the rubber-like material used in the method 600 may comprise any natural or synthetic rubber. For example, the rubber-like material may comprise one or more of isoprene polymers, chloroprene polymers, isobutylene polymers, styrene polymers, or butadiene polymers. In some embodiments, the rubber-like material may comprise monomers of isoprene, chloroprene, isobutylene, styrene, and/or butadiene that are polymerized (and/or co-polymerized) during vulcanization, e.g., in step 505 of method 500.
At step 603 in
At step 605, the method 600 may include sealing the distal ends of the extruded rubber-like material together to form a circular shaped tire. After the ends have been joined together, each of a plurality of hollow cores formed by the plurality of mandrels may extend along a circumference of the tire. For example, sealing the ends of the extruded material may comprise using one or more adhesives to connect the ends. Additionally or alternatively, as depicted in
Step 605 may include a vulcanization process distinct from step 603. Alternatively, steps 603 and 605 may comprise the same vulcanization process.
Methods 500 and 600 may be combined. For example, method 600 may include step 505 of method 500 in addition with or in lieu of step 605 for connecting the ends of the extruded rubber-like material together. Similarly, method 500 may include step 505 of method 500 in addition with or in lieu of step 605 for connecting the ends of the extruded rubber-like material together.
The foregoing description has been presented for purposes of illustration. It is not exhaustive and is not limited to precise forms or embodiments disclosed. Modifications and adaptations of the embodiments will be apparent from consideration of the specification and practice of the disclosed embodiments. For example, the described implementations include certain exemplary manufacturing components and apparatuses, but systems and methods consistent with the present disclosure can be implemented with other manufacturing apparatuses, including for example both hardware and software. In addition, while certain components have been described as being coupled to one another, such components may be integrated with one another or distributed in any suitable fashion.
Moreover, while illustrative embodiments have been described herein, the scope includes any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations based on the present disclosure. The elements in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the present specification or during the prosecution of the application, which examples are to be construed as nonexclusive. Further, the steps of the disclosed methods can be modified in any manner, including reordering steps and/or inserting or deleting steps.
The features and advantages of the disclosure are apparent from the detailed specification, and thus, it is intended that the appended claims cover all systems and methods falling within the true spirit and scope of the disclosure. As used herein, the indefinite articles “a” and “an” mean “one or more.” Similarly, the use of a plural term does not necessarily denote a plurality unless it is unambiguous in the given context. Words such as “and” or “or” mean “and/or” unless specifically directed otherwise. Further, since numerous modifications and variations will readily occur from studying the present disclosure, it is not desired to limit the disclosure to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the disclosure.
Other embodiments will be apparent from consideration of the specification and practice of the embodiments disclosed herein. It is intended that the specification and examples be considered as example only, with a true scope and spirit of the disclosed embodiments being indicated by the following claims.