Mounting arrangement of a self-supporting spoke structure for a non-pneumatic tire

Abstract

The non-pneumatic tire includes a lower ring having a first diameter and an upper ring having a second diameter. The upper ring is substantially coaxial with the lower ring. A support structure connects the lower ring to the upper ring. The support structure is composed of a plurality of spokes. The support structure is arranged and configured such that adjacent spokes among the plurality of spokes contact each other when a high-impact event occurs.

Description

Technical Field

[0001] The present disclosure relates to non-pneumatic tires. More particularly, the present disclosure relates to non-pneumatic tires having a support structure with spokes designed to contact each other upon the occurrence of a high-impact event.

Background Art

[0002] Various tire structures have been developed that allow a tire to travel in a non-inflated or under-inflated state. Non-pneumatic tires do not require inflation, while "run-flat tires" can continue to operate for an extended period of time and at a relatively high speed even after a puncture and partial or complete deflation. Non-pneumatic tires may include a support structure such as spokes or webbing that connect a lower ring to an upper ring. In some non-pneumatic tires, a circumferential tread may be attached to the upper ring of the tire.

[0003] The circumferential tread may include a tread band. The tread band may be a single layer or multi-layer band of material. Such a tread band may also be referred to as a shear band, shear element, or thin annular high-strength band element. When used in a non-pneumatic tire or a pneumatic tire in a partially pressurized or non-pressurized state, the shear element acts as a structural compression member. When used in a fully pressurized pneumatic tire, the shear element acts as a tension member.

[0004] Tire design involves balancing many factors, including but not limited to load capacity, handling, and ride comfort, for both pneumatic and non-pneumatic tires. Regardless of the balance chosen among these factors, non-pneumatic tires must be durable and able to withstand high-impact events such as collisions with curbs, potholes, or other obstacles or road defects.

Summary of the Invention

[0005] In one embodiment, the non-pneumatic tire includes a lower ring having a first diameter and an upper ring having a second diameter. The upper ring is substantially coaxial with the lower ring. A support structure connects the lower ring to the upper ring. The support structure is composed of a plurality of spokes. The plurality of spokes are arranged in a first group of spokes and a second group of spokes axially spaced from the first group of spokes. Each of the plurality of spokes includes a first end connected to the lower ring, a second end connected to the upper ring, and a boot at the first end. The boot has a floor portion. The floor portion is attached to the lower ring so as to connect the first end of the spoke to the lower ring.

[0006] In another embodiment, a method of manufacturing a non-pneumatic tire includes providing a lower ring having a first diameter and an upper ring having a second diameter greater than the first diameter. A plurality of scallops are formed on the lower ring. Each of the plurality of scallops has a first curved surface. A plurality of spokes are formed. Each spoke extends between a first end and a second end. A plurality of boots are formed. Each of the plurality of boots has a second curved surface. The plurality of boots are attached to respective ones of the plurality of spokes at the first end. The plurality of spokes are arranged in a first group of spokes and a second group of spokes axially spaced from the first group of spokes. The method further includes connecting the lower ring to the upper ring using the first group of spokes and the second group of spokes. The step of connecting the lower ring to the upper ring includes attaching the second curved surface of the boot to the first curved surface of one of the plurality of scallops to connect the first end of the spoke to the lower ring and connecting the second end of the spoke to the upper ring.

[0007] In yet another embodiment, the non-pneumatic tire includes a lower ring having a first radius of curvature. The lower ring is provided with a plurality of scallops. Each scallop has a first curved surface having a second radius of curvature. The upper ring is coaxial with the lower ring. The support structure connects the lower ring to the upper ring. The support structure is composed of a plurality of spokes. Each spoke extends between a first end and a second end. A boot is provided at the first end. The boot has a third radius of curvature. Each of the first radius of curvature and the second radius of curvature is different from the third radius of curvature.

Brief Description of the Drawings

[0008] In the accompanying drawings, together with the detailed description provided below, structures illustrating exemplary embodiments of the claimed invention are illustrated. Like elements are identified by the same reference numerals. It should be understood that an element shown as a single component may be replaced by a number of components, and an element shown as a number of components may be replaced by a single component. The drawings are not to scale, and the ratios of certain elements may be exaggerated for illustration.

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DETAILED DESCRIPTION OF THE INVENTION

[0009] The following includes definitions of selected terms used in this specification. The definitions include the scope of the terms and various examples or forms of components that can be used for implementation. The examples are not intended to be limiting. Both the singular and plural forms of the terms can be within the scope of the definition.

[0010] "Axial" and "axially" refer to a direction parallel to the rotation axis of the tire.

[0011] "Circumferential" and "circumferentially" refer to a direction extending along the outer circumference of the surface of the tread that is perpendicular to the axial direction.

[0012] "Radial" and "radially" refer to a direction perpendicular to the rotation axis of the tire.

[0013] As used herein, "tread" refers to the portion of the tire that contacts the road or ground at normal inflation and normal load.

[0014] General tire components are described by similar terms used in the following description. Of course, since the terms have slightly different implications, those skilled in the art should understand that none of the following terms are purely interchangeable with other terms used to describe general tire components.

[0015] In this specification, directions are described with reference to the axis of rotation of the tire. The terms "upward" and "upwardly" refer to the general direction towards the tread of the tire, and "downward" and "downwardly" refer to the general direction towards the axis of rotation of the tire. Thus, when relative directional terms such as "upper" and "lower" or "top" and "bottom" are used in relation to an element, the "upper" or "top" element is spaced closer to the tread than the "lower" or "bottom" element. Additionally, when relative directional terms such as "above" or "below" are used in relation to an element, an element "above" another element is closer to the tread than the other element.

[0016] The terms "inner" and "inwardly" refer to the general direction towards the equatorial plane of the tire, and "outer" and "outwardly" refer to the general direction away from the equatorial plane of the tire and towards the sidewall of the tire. Thus, when relative directional terms such as "inner" and "outer" are used in relation to an element, the "inner" element is spaced closer to the equatorial plane of the tire than the "outer" element.

[0017] Figures 1 to 5 illustrate one embodiment of the non-pneumatic tire 10. The non-pneumatic tire 10 is merely an exemplary figure and is not intended to be limiting. In the illustrated embodiment, the non-pneumatic tire 10 includes a substantially annular lower ring 20. The lower ring 20 can engage a vehicle hub (not shown) for attaching the tire 10 to a vehicle. The lower ring 20 has an inner surface 23 and an outer surface 24 and can be made of a polymer material, an elastomeric material, a metal, a composite material composed of a polymer reinforced with glass fibers or carbon fibers, or any other desired material or combination of materials.

[0018] The non-pneumatic tire 10 further includes a substantially annular upper ring 30. The upper ring 30 has a diameter larger than that of the lower ring 20 and is substantially coaxial with the lower ring 20. The upper ring 30 has an inner surface 33 and an outer surface 34 and can be made of a polymer material, an elastomeric material, a metal, a polymer reinforced with glass or carbon fibers, or any other desired material or combination of materials. The circumferential tread 70 is attached to the outer surface 34 of the upper ring 30. The circumferential tread 70 can be attached to the upper ring 30 with an adhesive, mechanically, or in any other desired arrangement.

[0019] As shown in FIG. 3, the circumferential tread 70 includes a tread band 72 and a tread layer 74. The tread band 72 and the tread layer 74 may be made of the same material or different materials. The tread layer 74 may be made of rubber and may include tread elements (not shown) such as grooves, ribs, blocks, lugs, sipes, studs, or any other desired elements. The tread band may include a filament assembly.

[0020] In the illustrated embodiment, the tread band 72 is shown as a single layer. In an alternative embodiment, the tread band may be a multi-layer band. Such a multi-layer tread band can include one or more layers of substantially non-extensible material. The layers may be formed from a sheet of material, a cord of material, a filament of material, or any other desired arrangement. In other alternative embodiments, the multi-layer tread band can include layers of extensible material such as elastomers. According to an exemplary embodiment, the tread band can include a pair of non-extensible layers separated by a layer of extensible material. In yet other alternative embodiments, the tread band may include a shear band, a shear element, or a band referred to as a thin annular high-strength band element.

[0021] The support structure 100 connects the lower ring 20 to the upper ring 30. The support structure 100 extends from the outer surface 24 of the lower ring 20 and the inner surface 33 of the upper ring 30. The support structure 100 is composed of a plurality of spokes 200. In the illustrated embodiment, the plurality of spokes 200 are arranged in two axially spaced-apart spoke groups, including a first spoke group 202 and a second spoke group 204 axially spaced from the first spoke group 202. In an alternative embodiment, the support structure can include three or more axially spaced-apart spoke groups.

[0022] As shown in FIG. 3, the first spoke group 202 and the second spoke group 204 are axially spaced from each other. In an alternative embodiment, the distance between the first spoke group and the second spoke group can be larger, smaller, or the first and second spoke groups can be arranged without a gap therebetween. When viewed from the perspective shown in FIG. 1, each spoke 200 of the first spoke group 202 is substantially convex with respect to the clockwise circumferential direction of the non-pneumatic tire 10, and each spoke of the second spoke group 204 is substantially concave with respect to the clockwise circumferential direction of the non-pneumatic tire 10.

[0023] All the spokes 200 of the first and second spoke groups 202, 204 have the same configuration. Therefore, the description of the spoke 200 is made with reference to the single spoke 200 shown in FIG. 6. The spoke 200 may be manufactured from a metal such as steel or aluminum, a polymer such as polyester or nylon, a composite material such as glass fiber or carbon fiber reinforced polymer, or any other desired material or combination of materials. The spoke 200 may be provided with a reinforcing material (not shown).

[0024] The spoke 200 extends between a first end 206 and a second end 208 and has a substantially rectangular cross-section including a first surface 210 and a second surface 212 facing opposite the first surface 210. The spoke thickness t refers to the distance between the first surface 210 and the second surface 212. In the illustrated embodiment, the spoke 200 has a constant thickness between the first end 206 and the second end 208. In an alternative embodiment, the thickness of the spoke may vary between the first end and the second end. For example, the spoke may have relatively thick portions at the first and second ends and a relatively thin portion between those ends. In other alternative embodiments, the spoke may have any desired cross-sectional shape (e.g., circular, diamond-shaped, hexagonal, etc.) or a combination of different cross-sectional shapes.

[0025] Towards the first end 206 of the spoke 200, an integral foot portion 214 is provided. The first surface 210 of the spoke 200 at the foot portion 214 is attached to the outer surface 24 of the lower ring 20 in order to connect the first end 206 of the spoke 200 to the lower ring 20. The foot portion 214 may be attached to the outer surface 24 of the lower ring 20 using welding, brazing, soldering, adhesives, mechanical fasteners (e.g., bolts, rivets), key / keyway, or any other desired arrangement. In the illustrated embodiment, the foot portion 214 is substantially linear and its overall length (the dimension of the foot portion extending along the circumferential direction of the tire) and overall width (the dimension of the foot portion extending along the axial direction of the tire) are fixed to the outer surface 24 of the lower ring 20. In an alternative embodiment, the foot portion may be a separate component attached to the spoke. In other alternative embodiments, the foot portion may be curved to match the radius of curvature of the outer surface of the lower ring or may have any other desired curvature. In yet other alternative embodiments, only a portion of the foot portion, or multiple separate portions, may be attached to the outer surface of the lower ring. In still other alternative embodiments, the foot portion may be attached under the outer surface of the lower ring or the spoke may extend through the lower ring such that the foot portion can be attached to the inner surface of the lower ring.

[0026] A flexure member 216 is provided at the second end 208 of the spoke 200. The flexure member 216 has a width extending along the axial direction of the tire. The flexure member 216 may be manufactured from a polymer (e.g., urethane or rubber), a thin curved metal piece, or any other desired material or combination of materials. In the illustrated embodiment, the flexure member 216 is provided as a rectangular parallelepiped and is arranged such that the ends of the flexure member 216 are aligned with the second end 208 of the spoke 200. In other alternative embodiments, the flexure member may be arranged such that the ends of the flexure member are recessed from the second end of the spoke, or the ends of the flexure member may extend beyond the second end of the spoke. In still other alternative embodiments, the flexure member may be replaced with a mechanical pin joint (i.e., a hinge).

[0027] The flexure member 216 includes a spoke-facing surface 218 and a ring-facing surface 220. The spoke-facing surface 218 of the flexure member 216 is attached to the second surface 212 of the spoke 200, and the ring-facing surface 220 is attached to the inner surface 33 of the upper ring 30 to connect the second end 208 of the spoke 200 to the upper ring 30. The attachment between the flexure member 216 and the spoke 200, or between the flexure member 216 and the upper ring 30, can be achieved using welding, brazing, soldering, adhesives, mechanical fasteners (e.g., bolts, rivets), key / keyway, or any other desired arrangement. For example, attachment can be made by directly casting urethane onto the spoke, whether or not the spoke is initially coated with a primer.

[0028] The flexure member 216 provides flexibility to the connection between the second end 208 of the spoke 200 and the upper ring 30. This flexibility reduces the possibility of high stresses occurring within the spoke 200, thereby improving the robustness of the non-pneumatic tire 10. Compared to the flexible connection provided by the flexure member 216, the connection provided by the foot portion 214 at the first end 206 of the spoke 200 is more rigid.

[0029] In alternative embodiments, the flexure member may have a shape or configuration different from that specifically illustrated and described. In other alternative embodiments, additional structure(s) or mechanism(s) may supplement the flexure member for attaching the second end of the spoke to the upper ring. In still other alternative embodiments, the flexure member may be omitted and the second end of the spoke may be attached directly to the upper ring. In these alternative embodiments, the second end of the spoke may be attached directly to the inner surface of the upper ring on the inner surface of the upper ring, or the spoke may extend through the upper ring such that the second end can be attached to the outer surface of the upper ring.

[0030] The spoke 200 includes a knee portion 222 between a first end 206 and a second end 208. The knee portion 222 has a first radius of curvature r1. According to an exemplary embodiment, the first radius of curvature r1 is 2 to 6 inches (5 to 15 cm). When attached to the upper and lower rings 20, 30, the knee portion 222 is curved concave with respect to the lower ring 20.

[0031] A transition portion 224 is provided between the knee portion 222 and the first end 206. The transition portion 224 has a second radius of curvature r2. According to an exemplary embodiment, the second radius of curvature r2 is 0 to 2 inches (0 to 5 cm). When attached to the upper and lower rings 20, 30, the transition portion 224 is curved convex with respect to the lower ring 20. Thus, for a single spoke 200, the knee portion 222 and the transition portion 224 are curved concave in opposite directions. In alternative embodiments, the knee portion and the transition portion are curved concave (or convex) in the same direction.

[0032] The foot portion 214 extends from the transition portion 224 to the first end 206 of the spoke 200. The first connection portion 226 connects the transition portion 224 to the knee portion 222, and the second connection portion 228 connects the knee portion 222 to the second end 208 of the spoke 200. In the illustrated embodiment, both the first and second connection portions 226, 228 are straight. In an alternative embodiment, the first connection portion or the second connection portion may be curved or may have any other desired configuration. In other alternative embodiments, the transition portion and the foot portion may be omitted. In such alternative embodiments, the first end of the spoke is disposed at the end of the first connection portion.

[0033] The base plane p1 intersects the transition portion 224 and the second end 208 of the spoke 200 and functions as a reference for aspects regarding the various dimensions of the spoke 200. The angle between the base plane p1 and the second plane p2 that extends tangentially to the outer surface 24 of the lower ring 20 at the transition portion 224 is α. According to an exemplary embodiment, the angle α is 5 to 20 degrees. The distance between the transition portion 224 and the second end 208 of the spoke 200 along a direction parallel to the base plane p1 is d1. According to an exemplary embodiment, the distance d1 is 10 to 15 inches (25 to 38 cm). The distance between the center of the transition portion 224 and the center of the first curvature r1 of the knee portion 222 along a direction parallel to the base plane p1 is d2. According to an exemplary embodiment, the value of the distance d2 is 40 to 70 percent of the distance d1. The maximum distance between the knee portion 222 and the base plane p1 along a direction perpendicular to the base plane p1 is d3. According to an exemplary embodiment, the distance d3 is 2 to 4 inches (5 to 10 cm).

[0034] Referring to FIG. 10, the transition portion 224 of one spoke 200 is separated from the first end 206 of the adjacent spoke 200 by a first spacing distance s1. The second ends 208 of the adjacent spokes 200 are separated from each other by a second spacing distance s2.

[0035] The non-pneumatic tire configured according to the above design parameters can provide a more robust assembly, especially with regard to impact performance. FIGS. 7 and 8 show the tire in an exemplary first state. As shown in FIGS. 7 and 8, according to a non-limiting example, in the first state, the tire 10 rolls on a flat surface while carrying a load (i.e., normal operation), and the non-pneumatic tire 10 deforms, but the adjacent spokes 200 do not contact each other. The absence of contact between adjacent spokes 200 during normal operation is desirable to avoid the generation of unnecessary stress in the structure of the non-pneumatic tire 10.

[0036] The non-pneumatic tire 10 is expected to be exposed to high-impact events such as hitting a curb, pothole, or other obstacle or road defect during its lifespan. During a high-impact event, the non-pneumatic tire 10 may deform at a level significantly higher than the deformation that occurs during normal operation.

[0037] FIGS. 9 and 10 show the tire in an exemplary second state, which is different from the first state. As shown in FIGS. 9 and 10, according to a non-limiting example, in the second state, the non-pneumatic tire 10 experiences a high-impact event where the tire rolls on a non-flat surface. According to one non-limiting example, the non-flat surface is a road defect that protrudes above the ground or sinks into the ground over a distance of 3 inches (8 cm). According to another non-limiting example, the non-flat surface is a road defect that protrudes above the ground or sinks into the ground over a distance of 4.5 inches (11 cm). According to yet another non-limiting example, the non-flat surface is a road defect that protrudes above the ground or sinks into the ground over a distance of 6 inches (15 cm).

[0038] The non-pneumatic tire 10 responds to high-impact events by deforming such that adjacent spokes 200 contact each other. Surprisingly, it has been found that contact between adjacent spokes 200 during a high-impact event significantly reduces the stress experienced by individual spokes 200 as compared to non-pneumatic tires where the spokes do not contact each other during high-impact events. The reduction in stress in individual spokes 200 is a result of contact between adjacent spokes 200, as the contact distributes the load among multiple spokes 200. In other words, rather than a single spoke 200 absorbing the load resulting from a high-impact event, multiple spokes 200 share the same load, thus reducing the peak load on any one individual spoke 200.

[0039] In the illustrated embodiment, the non-pneumatic tire 10 is arranged and configured such that at least three adjacent spokes 200 contact each other simultaneously during a high-impact event, and the contacting spokes 200 are positioned adjacent to an obstacle or road defect that is the cause of the high-impact event. In alternative embodiments, the non-pneumatic tire may be arranged and configured to have fewer or more adjacent spokes that contact each other simultaneously during a high-impact event. In other alternative embodiments, the adjacent spokes that contact each other simultaneously may be positioned at any location along the circumferential direction of the tire (i.e., they may be spaced apart from the obstacle or road defect that causes the high-impact event).

[0040] The design parameters of the spokes 200 and other components of the non-pneumatic tire 10 may be varied to provide the desired performance characteristics for the non-pneumatic tire 10. Preferably, these design parameters are selected such that contact between adjacent spokes 200 occurs before the spokes 200 begin to yield or otherwise experience any other form of damage.

[0041] The maximum distance d3 between the knee portion 222 and the base plane p1 along a direction perpendicular to the base plane p1 affects the rigidity of the spokes and when contact between adjacent spokes 200 occurs. Increasing the distance d3 physically moves each spoke 200 closer to the adjacent spoke 200, and thus causes contact between adjacent spokes 200 to occur relatively early. Additionally, increasing the distance d3 decreases the rigidity of the spokes 200, and thus increases the amount of deflection for a given load, thereby increasing the likelihood of contact between adjacent spokes 200. Decreasing the distance d3 has the opposite effect, physically moving each spoke 200 farther from the adjacent spoke 200, and thus causing contact between adjacent spokes 200 to occur relatively late. Additionally, decreasing the distance d3 increases the rigidity of the spokes 200, and thus decreases the amount of deflection for a given load, thereby decreasing the likelihood of contact between adjacent spokes 200.

[0042] The distance d2 between the transition portion 224 along a direction parallel to the base plane p1 and the center of the first radius of curvature r1 of the knee portion 222 affects when contact with adjacent spokes 200 occurs. When the distance d2 is a larger percentage of d1, as a result, contact between adjacent spokes 200 will occur relatively early. When the distance d2 is a smaller percentage of d1, as a result, contact between adjacent spokes 200 will occur relatively late.

[0043] The radius of curvature r1 of the knee portion 222 affects when contact with adjacent spokes 200 occurs. Decreasing the radius of curvature r1 will cause contact between adjacent spokes 200 to occur relatively late, and increasing the radius of curvature r1 will cause contact between adjacent spokes 200 to occur relatively early. The spoke thickness t affects the rigidity of the spokes 200. Increasing the spoke thickness t increases the rigidity of the spokes 200, and decreasing the spoke thickness decreases the rigidity of the spokes 200.

[0044] Additionally, it has been found that the vertical stiffness of the tire is affected by the combination of the spoke thickness t and the distance d3. Increasing the distance d3 decreases the tire stiffness, and decreasing the distance d3 increases the tire stiffness. As a result, in order to meet the target value of the tire stiffness, it has been found that spokes with a larger thickness t should be combined with a larger distance d3, and spokes with a smaller thickness t should be combined with a smaller distance d3.

[0045] Figure 11 is a flowchart showing an exemplary method of manufacturing a non-pneumatic tire. At 1010, a lower ring and an upper ring are provided. The lower ring and the upper ring having a first diameter have a second diameter that is larger than the first diameter. At 1020, a plurality of spokes are formed. The spokes may be formed using hot stamping, cold forming, extrusion, rolling, bending, or any other desired method. Additionally, the spokes may be formed using a plurality of composite manufacturing techniques (e.g., high pressure resin transfer molding). Each spoke extends between a first end and a second end. A knee portion is located between the first end and the second end, and a transition portion is located between the first end and the knee portion. The knee portion and the transition portion are curved concave in opposite directions. A foot portion extends from the transition portion.

[0046] At 1030, a flexure member is attached to the spokes. At 1040, the spokes are arranged in a first group of spokes and a second group of spokes that are axially spaced apart from the first group of spokes. Further, a plurality of spokes in the first group of spokes are arranged to curve concave with respect to a first circumferential direction of the tire, and a plurality of spokes in the second group of spokes are arranged to curve convex with respect to the first circumferential direction of the tire.

[0047] At 1040, the lower ring is connected to the upper ring using a first spoke group and a second spoke group. The foot portion of each spoke is attached to the lower ring so as to connect the first end of each spoke to the lower ring. The flexure member is attached to the upper ring so as to connect the second end of each spoke to the upper ring.

[0048] In an alternative embodiment, the foregoing steps may be performed in an order other than that specifically described. In other alternative embodiments, the method may include more or fewer steps.

[0049] Figures 12 and 12a show another embodiment of the spoke 1200. The spoke 1200 of Figures 12 and 12a is substantially the same as the spoke 200 of Figures 1 - 10, except for the differences described herein. Accordingly, similar features will be identified by similar numbers increased by a factor of "1000". In the spoke 200 shown in Figures 1 - 10, the second connection portion 228 is linear. In comparison, the spoke 1200 of Figures 12 and 12a has a curved second connection portion 1228 with a radius of curvature r3. The curved second connection portion 1228 in the spoke 1200 of Figures 12 and 12a significantly improves the self - supporting behavior compared to the linear second connection portion. According to one exemplary embodiment, the radius of curvature r3 is from 10 to 50 inches (25 to 127 cm).

[0050] In addition to the design parameters and resulting performance characteristic changes described above with respect to the spoke 200 shown in Figures 1 - 10, the radius of curvature r3 of the curved second connection portion 1228 in the spoke 1200 of Figures 12 and 12a can be varied to affect performance. The radius of curvature r3 of the curved second connection portion 1228 and the width w of the flexure member 1216 flexureinteract to affect the self - supporting performance. The smaller radius of curvature r3 of the curved second connecting portion 1228 reduces self - support and thus increases the stress during a high - impact event. The larger radius of curvature r3 of the curved second connecting portion 1228 increases self - support and thus reduces the stress during a high - impact event. However, this stress reduction only occurs up to a point. As the radius of curvature r3 increases (the limit being a radius of curvature r3 equal to infinity, which results in a straight second connecting portion), the effectiveness of self - support begins to decrease again.

[0051] The width w of the flexure member 1216 flexure affects its ability to exert torque on the end of the spoke 1200. This torque acts to straighten the curved second connecting portion 1228 when the tire rolls under standard load or when it undergoes a high - impact event. As a result, a curved second connecting portion 1228 having a smaller radius of curvature r3 is optimally matched with a flexure member 1216 having a larger width w flexure and a curved second connecting portion 1228 having a larger radius of curvature r3 is found to be optimally matched with a flexure member 1216 having a smaller width w flexure The ability of the flexure member 1216 to exert torque on the spoke 1200 is affected by the width w flexure of the flexure member 1216. In addition to this, it is affected by the rigidity of the material used to manufacture the flexure member 1216. As a result, when a softer material is used, a flexure member 1216 with a wider width w flexure is provided, and when a harder material is used, it is desirable to provide a flexure member 1216 with a narrower width w flexure .

[0052] The non - pneumatic tire described herein improves the robustness of the non - pneumatic tire by providing an arrangement in which adjacent spokes contact each other during a high - impact event. The contact between adjacent spokes results in multiple spokes sharing the load, thus significantly reducing the stress on any single spoke within the non - pneumatic tire. This improves the durability of the non - pneumatic tire.

[0053] In the above-described embodiment, the leg portion 214 of the spoke 200 is initially substantially straight and joined to the curved outer surface 24 of the lower ring 20. This joining process conforms the leg portion 214 to the curvature of the outer surface 24. This arrangement results in a relatively simple manufacturing process for the spoke 200 and the lower ring 20, but may give rise to other potential design difficulties. For example, in an embodiment with a flat leg portion, the main applied force acting at the joint between the spoke and the ring is a tensile force. This tensile force may cause cleavage failure at the leading edge of the spoke. As another example, the rotational position of each spoke with respect to the lower ring and the upper ring cannot be adjusted without introducing undesirable prestress in the spoke.

[0054] Rotational adjustment of the spoke may be necessary to account for manufacturing tolerances. Ideally, all the spokes of the non-pneumatic tire are identical, including the dimensions of the various elements (e.g., the lengths of the leg portion, the first connecting portion, and the second connecting portion, as well as the angles between these elements (e.g., the angle between the leg portion and the first connecting portion, or the angle between the first connecting portion and the second connecting portion)). However, in practice, it is unlikely that all the spokes will be identical. Manufacturing guidelines approve variables within the formed features of the product, such as material thickness and heat treatment tolerances. Additionally, these manufacturing guidelines approve variables within the angular tolerance for bending, and one guideline suggests a tolerance of + / - 1 degree.

[0055] FIGS. 13 and 14 illustrate how this + / - 1 degree tolerance can affect the support structure of the non-pneumatic tire. The non-pneumatic tires of FIGS. 13 and 14 are constructed in accordance with the embodiment of the non-pneumatic tire of FIGS. 1 - 6. Accordingly, similar features will be identified by similar numerals.

[0056] Figures 13 and 14 show the first spoke 200a, the second spoke 200b, and the third spoke 200c. In the first spoke 200a and the third spoke 200c, the angle θ between the foot portion 214 and the first connection portion 226 is 1 degree less than the specified design value, and in the second spoke 200b, this angle θ is 1 degree greater than the design value. Figure 13 shows the spoke 200 when the foot portion 214 is connected to the lower ring 20 and the second end 208 of each spoke 200 is in its natural or rest position (i.e., the location of the second end 208 of the spoke 200 before an external force is applied and before the flexure member 216 is attached to the upper ring 30). Figure 14 shows the spoke 200 after the second end 208 of the spoke 200 has been moved to the desired location and the flexure member 216 has been attached to the upper ring 30. As shown in Figure 13, a 1-degree deviation of the angle between the foot portion 214 and the first connection portion 226 from the specification can cause various problems, including the flexure member 216 being naturally placed on top of the upper ring 30 (second spoke 200b), or naturally placed below the upper ring 30 (first and third spokes 200a, 200c), and having an irregular spacing between adjacent spokes 200. Some of these problems can be corrected, as shown in Figure 14, by pushing the second end 208 of each spoke 200 into the desired position, but doing so introduces an undesirable prestress into the spoke 200. Theoretically, each spoke 200 can be rotated about its first end 206 to correct these problems. However, in practice, such rotation is not possible due to the geometry between the flat foot portion 214 and the outer surface of the lower ring 20.

[0057] FIG. 15 shows a partial alternative embodiment of a non-pneumatic tire having features that mitigate the above problems regarding manufacturing tolerances. FIGS. 16 and 17 show a single spoke of the non-pneumatic tire of FIG. 15. The arrangements shown in FIGS. 15-17 are substantially the same as the arrangements shown in FIGS. 1-6, except for any differences described herein. Accordingly, like features will be identified by like numerals incremented by the value of "2000".

[0058] The non-pneumatic tire 2010 includes a support structure 2100 that connects a lower ring 2020 to an upper ring (not shown). The support structure 2100 is composed of a plurality of spokes 2200 (only a single spoke is shown) arranged in a first spoke and a second group of spokes (not shown). The first group of spokes and the second group of spokes are offset and spaced from each other in the axial direction of the non-pneumatic tire 2010.

[0059] Each spoke 2200 extends between a first end 2206 and a second end 2208 and includes a first surface 2210 and a second surface 2212. A flexure member 2216 is provided at the second end 2208 of the spoke 2200. A knee portion 2222 is provided between the first end 2206 and the second end 2208. A first connection portion 2226 connects the first end 2206 to the knee portion 2222. A second connection portion 2228 connects the knee portion 2222 to the second end 2208 of the spoke 2200. Unlike the spokes shown in the embodiments of FIGS. 1-6, the spokes shown in the embodiments of FIGS. 15-17 do not include a transition portion or a foot portion.

[0060] The boot 2215 is attached to the first end 2206 of the spoke 2200. The boot 2215 may be manufactured from steel, aluminum, titanium, magnesium, composite materials (e.g., aluminum metal matrix, carbon fiber, reinforced plastic), or any other desired material, and may be attached to the spoke 2200 using an adhesive, mechanical fasteners, a combination of an adhesive and mechanical fasteners, welding, or any other desired arrangement. The boot 2215 extends between a first edge 2327 and a second edge 2329. The distance between the first edge 2327 and the second edge 2329 defines the boot width. As used herein, "width" refers to the dimension of a component that extends along the axial direction of the non-pneumatic tire 2010. In the illustrated embodiment, the width of the boot 2215, the width of the spoke 2200, and the width of the lower ring 2020 are all equal to each other. In alternative embodiments, the widths of the boot, spoke, and lower ring may be increased or decreased such that the width of any one of these elements is greater than or less than the width of another one of the elements.

[0061] The boot 2215 includes a first side portion 2217 and a second side portion 2219. The first side portion 2217 includes a first straight roof portion 2221. The second side portion 2219 includes a second arcuate roof portion 2227. The first roof portion 2221 and the second roof portion 2227 intersect at a vertex 2229. The spoke 2200 enters the boot 2215 through an opening 2231 provided in the second arcuate roof portion 2227. A first wall portion 2233 extends from the first roof portion 2221 at an obtuse angle, and a second wall portion 2235 extends from the second roof portion 2221 at an obtuse angle. Both the first wall portion 2233 and the second wall portion 2235 are straight and extend parallel to each other. A floor portion 2237 extends between the first wall portion 2233 and the second wall portion 2235. A first end 2206 of the spoke 2200 is spaced from the floor portion 2237 when the spoke 2200 is received within the boot 2215. The boot 2215 may provide a more rigid attachment than a spoke embodiment without a boot. The design of the boot and the orientation of the spoke relative to the boot can be varied to provide a non-pneumatic tire having desired performance characteristics.

[0062] On an outer surface 2024 of the lower ring 2020, a plurality of scallops 2025 equal in number to the total number of spokes 2200 within the support structure 2100 are provided. The floor portion 2237 of the boot 2215 is curved and has a radius of curvature r equal to the radius of curvature r s of the corresponding scallop 2025 fpIt has. The scallops 2025 are spaced apart from each other along the circumferential direction of the non-pneumatic tire 2010 and are arranged in first and second scallop groups (not shown). Similar to the separation between the first spoke group and the second spoke group, the scallop groups are also offset and separated from each other in the axial direction of the non-pneumatic tire 2010. The floor portions 2237 of the boots 2215 are joined to the respective scallops 2025 to attach the first ends of the spokes 2200 to the lower ring 2020. The flexure members 2216 are joined to the upper ring 2030 so as to connect the second ends 2208 of the spokes 2200 to the upper ring 2030. In an alternative embodiment, the boots or flexure members may be attached to the scallops or upper rings respectively using any desired arrangement.

[0063] The above arrangement helps to solve potential design problems associated with the embodiment of the spoke with a flat foot portion regarding spoke manufacturing tolerances. By providing the non-pneumatic tire 2010 with the spokes 2200 having boots 2215 with curved floor portions 2237 and corresponding curved scallops 2205, the main applied force acting on the joint between the boot 2215 and the lower ring 20 is a shear force rather than the tension seen in the flat foot portion embodiment. This change reduces the possibility of a cleavage type failure mode occurring at the connection between the spoke 2200 and the lower ring 2020. Further, the shear force acting on the joint between the boot 2215 and the lower ring 2020 results in a substantially stronger failure mode for the joint in the case of the most commonly used adhesives.

[0064] Additionally, the curved floor portions 2237 of the boots 2215 and the scallops 2025 allow adjustment of the rotational position of each spoke 2200 with respect to the lower ring 2020 and the upper ring 2030 without pre-introducing stress into the spokes as in the case of the flat foot portion embodiment. These curved surfaces also allow a constant adhesive gap to be maintained between the boot 2215 and the scallop 2025 during such adjustment of the rotational position.

[0065] The radius of curvature r of the bed portion 2237 fp and the radius of curvature r of the scallop 2025 s have been found to should follow a specific design principle in order to provide the above-described flexibility regarding rotational position adjustment. According to one exemplary design principle, the radius of curvature r of the bed portion 2237 fp and the radius of curvature r of the scallop 2025 s are different from the radius of curvature r of the outer surface 2024 of the lower ring 2020 lr and are different from each other.

[0066] In the illustrated embodiment, both the bed portion 2237 and the scallop 2025 of the boot 2215 are convex with respect to the inner surface 2023 of the lower ring 2020, and the radius of curvature r of the bed portion 2237 fp and the radius of curvature r of the scallop 2025 s are both constant and equal to each other. Additionally, the scallop 2025 is formed directly on the lower ring 2020. In an alternative embodiment, the bed portion of the boot may be convex with respect to the inner surface of the spoke, and the lower ring may be provided with corresponding bumps that are similarly convex with respect to the inner surface of the spoke. In other alternative embodiments, the radius of curvature of the bed portion or the radius of curvature of the scallop or bump may be variable or different from each other. In still other alternative embodiments, the scallop or bump may be formed on a sleeve fixed to the outer surface of the lower ring.

[0067] Additionally, it has been found that the boot can be used without a scallop on the inner ring. In such an arrangement, the bed portion of the boot has a shape that complements the shape of the outer surface of the lower ring. According to one non-limiting example where no scallop is used, the bed portion of the boot has a radius of curvature that is substantially the same as the radius of curvature of the outer surface of the lower ring. Further, it has been found that the scallop on the lower ring may have a shape other than curved. According to one non-limiting example, the scallop may be provided as a flat portion on the outer surface of the lower ring. In this arrangement, the bed portion of the boot is flat to complement the flat portion on the lower ring.

[0068] FIG. 18 shows a modified example of the boot 3215 for a non-pneumatic tire. The boot 3215 in FIG. 18 is substantially the same as the boot 2215 shown in the non-pneumatic tire 2010 of FIGS. 15 to 17, except for the differences described in this specification. Therefore, similar features will be identified by similar numbers increased by a factor of "1000".

[0069] The boot 3215 includes a first side portion 3217 and a second side portion 3219. The first side portion 3217 includes a first linear roof portion 3221. The second side portion 3219 includes a second stepped roof portion 3227. The first roof portion 3221 and the second roof portion 3227 intersect at a vertex 3229. The spoke 3200 enters the boot through an opening 3231 provided in the second roof portion 3227. The opening 3231 extends across the entire width of the boot 6548 and separates the second roof portion 3227 into a first step 3227a and a second step 3227b. A linear wall portion 3235 extends substantially at a right angle from the second step 3227b. The wall portion 3235 extends substantially parallel to the first roof portion 3221. A linear ceiling portion 3239 extends from the wall portion 3235 at an arcuate angle. Together, the linear ceiling portion 3239 and the wall portion 3235 define a substantially V-shaped notch. A floor portion 3237 extends between the first roof portion 3221 and the ceiling portion 3239. The floor portion 3237 has a radius of curvature r s equal to the radius of curvature r fp of a corresponding scallop 3025 provided on the outer surface 3024 of the lower ring 3020.

[0070] The specific arrangement of the boot 3215 can enable adjustment of the local stiffness of the boot 3215 to reduce peak stresses in the adhesive or other fastening arrangements. This reduction in peak stress can be provided by a V-shaped notch defined by the linear ceiling portion 3239 and the wall portion 3235. The design of the boot and the orientation of the spokes relative to the boot can be altered to provide a non-pneumatic tire having certain desired performance characteristics. For example, increasing the size of the V-shaped notch can decrease the stiffness of the boot, and decreasing the size of the notch can increase the stiffness of the boot. As another example, changing the location where the spoke enters the boot can also change the stresses in the boot and the adhesive or other fastening arrangements.

[0071] FIG. 19 shows an end cap 5000 that can be used with a spoke 5002 having a boot 5004. The end cap 5000 may be provided to limit "bleed-out" of the adhesive during the joining process between the boot and the lower ring 5003. Additionally, the end cap may act as a structural member to reinforce the boot 5004.

[0072] The end cap 5000 may be manufactured from metal, composite material, plastic, rubber, polymer, or any other desired material or combination of materials. The end cap 5000 includes a boot mating surface 5006 and an outward-facing surface 5008. The boot mating surface 5006 is attached to the boot 5004 to secure the end cap 5002 to the boot 5004. This attachment can be achieved using an adhesive, mechanical fasteners, a combination of an adhesive and mechanical fasteners, or any other desired fastening arrangement. The outward-facing surface 5008 may be smooth or may be provided with functional or decorative features (e.g., a company logo).

[0073] The end cap 5000 includes a first roof portion 5010 and a second roof portion 5012 that intersect at a vertex 5014. A first wall portion 5016 extends from the first roof portion 5010, and a second wall portion 5018 extends from the second roof portion 5012. A floor portion 5020 extends between the first wall portion 5016 and the second wall portion 5018. In the illustrated embodiment, the outer shape of the end cap 5000 is substantially the same as the outer shape of the boot 5004 to which the end cap 5000 is attached. In an alternative embodiment, the end cap 5000 may have any desired outer shape (i.e., an outer shape different from the outer shape of the boot).

[0074] Figures 20-22 show another embodiment of a boot 4215 for a non-pneumatic tire. The boot 4215 is similar to the boot 2215 shown in the non-pneumatic tire 2010 of FIGS. 15-17, except for the differences described herein. Accordingly, similar features will be identified by similar numbers increased by a factor of "2000".

[0075] The boot 4215 includes a first component 4217 and a second component 4219. The first component 4217 and the second component 4219 are separate and distinct components. The first component 4217 and the second component 4219 define a gap 4231 for receiving a spoke 4200. When received in such a manner, the spoke 4200 is sandwiched between the first component 4217 and the second component 4219.

[0076] The first component 4217 includes a linear roof portion 4221 and a floor portion 4237. The floor portion 4237 has a radius of curvature r that is substantially equal to the radius of curvature r of a corresponding scallop 4025 provided on the outer surface 4024 of the lower ring 4020 s substantially equal to the radius of curvature r fpIt has. Each first component 4217 is connected to the lower ring 4020 by two first fasteners 4270. An adhesive (not shown) may be used to strengthen the connection between the first component 4217 and the lower ring 4020 by joining the floor portion 4237 to the scallop 4025. The adhesive can prevent wear between various components due to cyclic loading and can also prevent deterioration (e.g., corrosion) resulting from exposure to environmental elements. In an alternative embodiment, the first component may have any desired shape (e.g., a curved roof portion).

[0077] In the illustrated embodiment, each first fastener 4270 is provided as an assembly including a threaded rod, a washer, and a nut. The threaded rod engages a female thread provided in the first component 4217. In an alternative embodiment, each first fastener can have any desired arrangement (e.g., a socket head cap screw, two nuts provided at both ends of the threaded rod instead of a female thread on the first component, and a screw or a flanged stud that threads into a female thread provided on the lower ring through the first component). In other alternative embodiments, each of the first fasteners may be provided with a different arrangement (e.g., a threaded rod, a washer, and a nut for one of the first fasteners, and a socket head cap screw for the other of the first fasteners). In still other alternative embodiments, there may be more or fewer first fasteners.

[0078] The first fastener 4270 extends through the lower ring 4020, the floor portion 4237, and the straight roof portion 4221. When arranged in such a manner, the floor portion 4237 is attached to the lower ring 4020. In an alternative embodiment, the first fastener, the lower ring, and / or the first component may be dimensioned and configured such that the first fastener does not extend through the floor portion or the straight roof portion. For example, the first fastener can be made shorter such that the first fastener terminates within the first component rather than extending through the straight roof portion.

[0079] The second component 4219 is attached to the first component 4217 by a plurality of second fasteners 4272. The second fasteners 4272 also attach the spokes 4200 to the boot 4215. In the illustrated embodiment, the second fasteners 4272 are eight socket head cap screws that are aligned with each other. The threads of the socket head cap screws engage female threads provided in the second component 4219. In an alternative embodiment, the second fastener may have any desired arrangement (e.g., a nut that engages the threads of the socket head cap screw rather than female threads on the second component). In other alternative embodiments, there may be more or fewer second fasteners. In yet other alternative embodiments, the second fasteners may be offset from each other.

[0080] The second fastener 4272 extends through the linear roof portion 4221 of the first component 4217, the spoke 4200, and the wall portion 4235 of the second component 4219. According to this arrangement, the spoke 4200 is effectively clamped between the first component 4217 and the second component 4219. An adhesive (not shown) can enhance the connection between the first component 4217 and the second component 4219 and the spoke 4200 by joining these components together. The adhesive can prevent wear between various components due to cyclic loading and can also prevent deterioration (e.g., corrosion) resulting from exposure to environmental elements. In an alternative embodiment, the second fastener, the second component, the spoke, and the first component may be dimensioned and configured such that the second fastener does not extend through the wall portion of the second component or the linear roof portion of the first component. For example, the second fastener can be made shorter such that the second fastener terminates within the second component rather than extending through the wall portion. In other alternative embodiments, the orientation of the second fastener may be reversed such that the second fastener extends through the second component and then the spoke and engages a female thread provided on the first component. In yet other alternative embodiments, depending on the material used to manufacture the spoke, the second component may be omitted. According to this example, the second fastener can include a nut and bolt where the nut engages the surface of the spoke, or the threaded portion of the second fastener can engage a female thread provided on the spoke.

[0081] Accordingly, the spoke 4200 is attached to the lower ring 4020 by a boot 4215 collectively composed of a first part 4217, a second part 4219, a first fastener 4270, and a second fastener 4272. In particular, the first part 4217, the second part 4219, and the second fastener 4272 attach the boot 4215 to the spoke 4200, and the first fastener 4270 attaches the floor portion 4237 to the lower ring 4020. This arrangement provides a robust attachment mechanism for the spoke, enabling the individual removal, maintenance, and installation of a single spoke. Additionally, this arrangement does not intrude into the area of the spoke designed to flex, thereby ensuring proper support of the load applied by the non-pneumatic tire.

[0082] Separate embodiments and variations are shown and described in FIGS. 1 - 22, but the disclosed features are not limited to only the described embodiments. Instead, various features can be combined between embodiments as needed. For example, the arrangement of the spoke with the boot shown in FIGS. 15 - 17 may be combined with the curved connection portion of the spoke shown in FIGS. 12 and 12a.

[0083] The terms "includes" or "including" are intended to be inclusive, in the same manner as the term "comprising", when interpreted as used in this specification or the claims of a patent as a transitional word in a claim. Further, where the term "or" is used (e.g., A or B), it is intended to mean "A or B, or both". Where Applicants intend to indicate "only A or B but not both", the term "only A or B but not both" is used. Accordingly, the use of the term "or" in this specification is inclusive and not exclusive. See Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d Ed. 1995). Also, the terms "in" or "into" are intended to additionally mean "on" or "onto" as used in this specification or the claims of a patent. Further, where the term "connect" is used in this specification or the claims of a patent, it is intended to mean not only "directly connected to", but also "indirectly connected to", such as through one or more other components.

[0084] Although this application has been illustrated by the description of its embodiments and those embodiments have been described in considerable detail, it is not the intention of the applicants to limit the appended claims to such detail or in any way. Additional advantages and modifications will readily occur to those skilled in the art. Accordingly, this application in its broader aspects is not limited to the specific details, representative apparatus and methods, and examples shown and described. For example, each spoke may be provided with a rubber coating to cushion the impact when contact occurs between adjacent spokes. Thus, departures from such details may be made without departing from the spirit or scope of the general inventive concept of the applicant.

Claims

1. A non-pneumatic tire comprising: a lower ring having a first diameter; an upper ring having a second diameter and substantially coaxial with the lower ring; a support structure connecting the lower ring to the upper ring and comprising a plurality of spokes, the plurality of spokes being arranged in a first group of spokes and a second group of spokes axially spaced from the first group of spokes, each of the plurality of spokes having: a first end connected to the lower ring; a second end connected to the upper ring; a boot at the first end, the boot having a floor portion attached to the lower ring so as to connect the first end of the spoke to the lower ring; a plurality of scallops provided on the lower ring, each of the plurality of scallops having a first curved surface, the floor portion of the boot being provided as a second curved surface; a support structure, wherein each of the first curved surface and the second curved surface is convex with respect to the inner surface of the lower ring.

2. (Cancelled)

3. (Cancelled)

4. The first curved surface has a first radius of curvature, the second curved surface has a second radius of curvature, and at least one of the first radius of curvature and the second radius of curvature is constant. The non-pneumatic tire according to claim 1.

5. The first curved surface has a first radius of curvature, the second curved surface has a second radius of curvature, and at least one of the first radii of curvature is equal to the second radius of curvature. The non-pneumatic tire according to claim 1.

6. The first curved surface has a first radius of curvature, the second curved surface has a second radius of curvature, the outer surface of the lower ring has a third radius of curvature, and each of the first radius of curvature and the second radius of curvature is different from the third radius of curvature. The non-pneumatic tire according to claim 1.

7. The lower ring has a first width, the spoke has a second width, the boot has a third width, and the third width is equal to at least one of the first width and the second width. The non-pneumatic tire according to claim 1.

8. Each of the plurality of spokes further includes an end cap, and the end cap is attached to an edge of the boot. The non-pneumatic tire according to claim 1.

9. The boot has a first outer shape, the end cap has a second outer shape, and the second outer shape is substantially the same as the first outer shape. The non-pneumatic tire according to claim 8.

10. Each of the plurality of spokes A knee portion located between the first end and the second end, and is curved concave with respect to the lower ring, and the knee portion; A transition portion located between the first end and the knee portion, and is curved convex with respect to the lower ring, and the transition portion. The non-pneumatic tire according to claim 1.

11. A method for manufacturing a non-pneumatic tire, Providing a lower ring having a first diameter and an upper ring having a second diameter larger than the first diameter; Forming a plurality of scallops on the lower ring, each of the plurality of scallops having a first curved surface; Forming a plurality of spokes, each spoke extending between a first end and a second end; Forming a plurality of boots, each of the plurality of boots having a second curved surface; Attaching one of the plurality of boots to each of the plurality of spokes at the first end; Arranging the plurality of spokes into a first group of spokes and a second group of spokes axially spaced from the first group of spokes; Connecting the lower ring to the upper ring using the first group of spokes and the second group of spokes. The step of connecting the lower ring to the upper ring includes attaching the second curved surface of the boot to the first curved surface of one of the plurality of scallops, connecting the first end of the spoke to the lower ring, and connecting the second end of the spoke to the upper ring. A method for manufacturing a non-pneumatic tire including the step of connecting.

12. Forming the plurality of scallops includes providing the first curved surface as a first convex surface with respect to the inner surface of the lower ring, and forming the plurality of boots includes providing the second curved surface as a second convex surface with respect to the inner surface of the lower ring. A method of manufacturing a non-pneumatic tire according to claim 11.

13. Forming the plurality of scallops includes providing the first curved surface having a first radius of curvature, and forming the plurality of boots includes providing the second curved surface having a second radius of curvature. The first radius of curvature and the second radius of curvature are different from a third radius of curvature of an outer surface of the lower ring. A method of manufacturing a non-pneumatic tire according to claim 11.

14. A step of forming a plurality of end caps; And attaching one of the plurality of end caps to each of the edges of the plurality of boots. A method of manufacturing a non-pneumatic tire according to claim 11.

15. Forming the plurality of end caps includes forming each of the plurality of end caps with a first outer shape, and forming the plurality of boots includes forming each of the plurality of boots with a second outer shape. The first outer shape is substantially the same as the second outer shape. A method of manufacturing a non-pneumatic tire according to claim 14.

16. The boot includes a fastener that attaches the floor portion to the lower ring. A non-pneumatic tire according to claim 1.

17. The boot includes a first component and A second component, and the first component and the second component are separate components. A non-pneumatic tire according to claim 1.

18. The first end of the spoke is sandwiched between the first component and the second component of the boot. A non-pneumatic tire according to claim 17.

19. The boot includes a fastener, and the fastener of the boot, the first component, and the second component attach the boot to the first end of the spoke. A non-pneumatic tire according to claim 18.

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