Leaf spring support for spoke structure of non-pneumatic tire

Abstract

A 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 supporting structure is composed of a plurality of spokes. The support structure is arranged and configured such that adjacent spokes of the plurality of spokes contact each other upon occurrence of a high impact event.

Description

Technical Field

[0001] The present disclosure relates to a non-pneumatic tire. More specifically, the present disclosure relates to a non-pneumatic tire having a support structure with spokes designed to contact each other during a high impact event. Background Art

[0002] Various tire constructions have been developed that enable the tire to be driven in an uninflated or underinflated state. Non-pneumatic tires do not require inflation, while "run-flat tires" can continue to be driven at relatively high speeds for extended periods of time after being punctured and partially or completely decompressed. Non-pneumatic tires may include support structure, such as spokes or webs, connecting 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 of material or a multi-layer band. Such a tread band may also be referred to as a shear band, a shear element, or a thin, annular high-strength band element. When used in a non-pneumatic tire or in a pneumatic tire in a partially pressurized or unpressurized 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 for both pneumatic and non-pneumatic tires involves a balance of many factors, including but not limited to load capacity, handling, and ride quality. Regardless of the balance chosen between these factors, non-pneumatic tires must be durable and able to withstand high impact events, such as hitting curbs, potholes or other obstacles or road imperfections. Summary of the invention

[0005] In one embodiment, a 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 into a first spoke group and a second spoke group axially spaced from the first spoke group. Each of the plurality of spokes includes a first end connected to the lower ring and a second end connected to the upper ring. A transition portion is located between the first end and the second end. An auxiliary spring is nested with the transition portion of the spoke.

[0006] In another embodiment, a method for 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 spokes are formed. Each spoke extends between a first end and a second end. Each spoke has a transition portion between the first end and the second end. Each spoke has an auxiliary spring nested with the transition portion. The plurality of spokes are arranged into a first spoke group and a second spoke group axially spaced apart from the first spoke group. The lower ring is connected to the upper ring through the first spoke group and the second spoke group.

[0007] In yet another embodiment, a 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. Each of the plurality of spokes is provided with an auxiliary spring nested with a curved portion of the spoke. The auxiliary spring is arranged and configured to reduce stress in the associated spoke. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In the accompanying drawings, structures are shown which, together with the detailed description provided below, describe exemplary embodiments of the invention protected by the claims. Similar elements are indicated by the same reference numerals. It should be understood that elements shown as a single component may be replaced with multiple components, and elements shown as multiple components may be replaced with a single component. The drawings are not drawn to scale, and for illustrative purposes, the proportions of certain elements may be exaggerated.

[0009] Figure 1 is a side view of one embodiment of a non-pneumatic tire,

[0010] Figure 2 yes Figure 1 Another side view of a non-pneumatic tire,

[0011] Figure 3 yes Figure 1 The cross-sectional view along 3-3,

[0012] Figure 4 yes Figure 1 Detailed view of area A,

[0013] Figure 5 yes Figure 1 Detail of region A of FIG. 1 with some features removed for clarity.

[0014] Figure 6 yes Figure 1 Detail of a single spoke used in a non-pneumatic tire.

[0015] Figure 7 When the tire is on a flat surface and carrying a normal load Figure 1 a side view of a portion of a non-pneumatic tire,

[0016] Figure 8 When the tire is on a flat surface and carrying a normal load Figure 1 A side view of a portion of a non-pneumatic tire with some features removed for clarity.

[0017] Fig. 9 When the tire is on an uneven surface Figure 1 a side view of a portion of a non-pneumatic tire,

[0018] Fig.10 When the tire is on an uneven surface Figure 1 A side view of a portion of a non-pneumatic tire with some features removed for clarity.

[0019] Fig.11 It shows the manufacturing Figure 1 A flowchart of a method for a non-pneumatic tire,

[0020] Fig.12 is another embodiment of a spoke for a non-pneumatic tire,

[0021] Fig.12a yes Fig.12 End view of the spoke along II,

[0022] Fig.13 is a side view of a portion of an alternative embodiment of a non-pneumatic tire,

[0023] Fig.14 yes Fig.13 Detail of a single spoke and auxiliary spring used in a non-pneumatic tire.

[0024] Fig.14a yes Fig.14 The view along AA,

[0025] Fig.15 yes Fig.14 A detailed view of a portion of

[0026] Figure 16a-16c It is a variation on a part of the auxiliary spring.

[0027] Figures 17a-17c They are shown respectively Figure 16a-16c A graph of performance metrics exhibited by the assist spring variations shown,

[0028] Figures 18a-18d Another variation of a part of the auxiliary spring,

[0029] Fig.19 yes Figure 13-15 A variation of the spoke arrangement shown in , and

[0030] Fig. 20 yes Figure 13-15 Another variation of the spoke arrangement is shown in . DETAILED DESCRIPTION

[0031] The following includes definitions of selected terms used herein. These definitions include various examples or forms of components that fall within the scope of the term and can be used for implementation. The examples are not intended to be limiting. Both singular and plural forms of the terms may be within the definitions.

[0032] "Axial" and "axially" refer to directions parallel to the tire's axis of rotation.

[0033] “Circumferential” and “circumferentially” refer to directions perpendicular to the axial direction extending along the circumference of the surface of the tread.

[0034] "Radial" and "radially" refer to directions perpendicular to the tire's axis of rotation.

[0035] As used herein, "tread" means that portion of the tire that comes into contact with the road or ground under normally inflated and normally loaded conditions.

[0036] Although similar terms are used in the following description to describe common tire components, it should be understood that because these terms carry slightly different meanings, one of ordinary skill in the art would not consider any of the following terms to be completely interchangeable with another term used to describe common tire components.

[0037] Directions are set forth herein with reference to the axis of rotation of the tire. The terms "upwardly" and "upwardly" refer to a general direction toward the tread of the tire, while "downwardly" and "downwardly" refer to a general direction toward the axis of rotation of the tire. Thus, when relative directional terms such as "upper" and "lower" or "top" and "bottom" are used in conjunction with an element, the "upper" or "top" element is spatially closer to the tread than the "lower" or "bottom" element. Additionally, when relative directional terms such as "above" or "below" are used in conjunction with an element, if an element is "above" another element, it means that the element is closer to the tread than the other element.

[0038] The terms "inwardly" and "inwardly" refer to general directions toward the equatorial plane of the tire, while "outwardly" and "outwardly" refer to general directions away from the equatorial plane of the tire and toward the sides of the tire. Thus, when relative directional terms such as "inner" and "outer" are used in conjunction with an element, the "inner" element is spatially closer to the equatorial plane of the tire than the "outer" element.

[0039] Figures 1 to 5 One embodiment of a non-pneumatic tire 10 is shown. The non-pneumatic tire 10 is shown for exemplary purposes only and is not intended to be limiting. In the illustrated embodiment, the non-pneumatic tire 10 includes a generally annular lower ring 20. The lower ring 20 can engage a vehicle wheel hub (not shown) to attach the tire 10 to the vehicle. The lower ring 20 has an inner surface 23 and an outer surface 24, and can be made of a polymeric material, an elastomeric material, a metal, a composite composed of a polymer reinforced with glass or carbon fiber, or any other desired material or combination of materials.

[0040] The non-pneumatic tire 10 also includes a generally annular upper ring 30. The upper ring 30 has a diameter greater than the diameter 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 may be made of a polymeric material, an elastomeric material, a metal, a composite composed of a polymer reinforced with glass or carbon fiber, or any other desired material or combination of materials. A circumferential tread 70 is attached to the outer surface 34 of the upper ring 30. The circumferential tread 70 may be attached to the upper ring 30 adhesively, mechanically, or by any other desired arrangement.

[0041] like Figure 3 As shown, 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, posts, or any other desired tread elements. The tread band may include a filament assembly.

[0042] In the illustrated embodiment, the tread band 72 is shown as a single layer. In an alternative embodiment, the tread band can be a multi-layer band. Such a multi-layer tread band may include one or more layers of substantially inextensible material. The layer may be formed by a sheet of material, a rope of material, a thread of material, or any other desired arrangement. In other alternative embodiments, the multi-layer tread band may include a layer of extensible material, such as an elastomer. According to an example embodiment, the tread band may include a pair of inextensible layers separated by a layer of extensible material. In other alternative embodiments, the tread band may include a band known as a shear band, a shear element, or a thin annular high-strength belt element.

[0043] 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 into two axially spaced spoke sets, including a first spoke set 202 and a second spoke set 204 axially spaced from the first spoke set 202. In alternative embodiments, the support structure may include more than two axially spaced spoke sets.

[0044] like Figure 3 As shown, the first spoke group 202 and the second spoke group 204 are spaced apart from each other in the axial direction. In alternative embodiments, the space between the first spoke group and the second spoke group can be larger or smaller, or the first spoke group and the second spoke group can be arranged with no space between them. Figure 1Each spoke 200 of the first spoke set 202 is substantially convex relative to the clockwise circumferential direction of the non-pneumatic tire 10 and each spoke of the second spoke set 204 is substantially concave relative to the clockwise circumferential direction of the non-pneumatic tire 10 when viewed at the angle shown.

[0045] All spokes 200 of the first spoke group 202 and the second spoke group 204 have the same configuration. Therefore, the description of the spokes 200 will refer to Figure 6 The spoke 200 is made of a single spoke 200 shown in FIG. The spoke 200 may be made of a metal such as steel or aluminum, a polymer such as polyester or nylon, a composite such as a glass fiber or carbon fiber reinforced polymer, or any other desired material or material combination. The spoke 200 may be provided with reinforcements (not shown).

[0046] The spoke 200 extends between a first end 206 and a second end 208 and has a generally 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 alternative embodiments, the thickness of the spoke may vary between the first end and the second end. For example, the spoke may have a relatively thick portion at the first end and the second end, and a relatively thin portion between the ends. In other alternative embodiments, the spoke may have any desired cross-sectional shape (e.g., circular, diamond, hexagonal, etc.) or may have a combination of different cross-sectional shapes.

[0047] An integral foot 214 is provided toward the first end 206 of the spoke 200. The first surface 210 of the spoke 200 is attached to the outer surface 24 of the lower ring 20 at the foot 214 to connect the first end 206 of the spoke 200 to the lower ring 20. The foot 214 can be attached to the outer surface 24 of the lower ring 20 using welding, brazing, soldering, adhesives, mechanical fasteners (e.g., bolts, rivets), keys / keyways, or any other desired arrangement. In the illustrated embodiment, the foot 214 is substantially straight and the entire length (the dimension of the foot extending in the circumferential direction of the tire) and the entire width (the dimension of the foot extending in the axial direction of the tire) are fixed to the outer surface 24 of the lower ring 20. In alternative embodiments, the foot can be a separate component attached to the spoke. In other alternative embodiments, the foot can be curved to match the radius of curvature of the outer surface of the lower ring or have any other desired curvature. In further alternative embodiments, only a portion or multiple discrete portions of the foot can be attached to the outer surface of the lower ring. In other alternative embodiments, the feet may be attached below the outer surface of the lower ring, or the spokes may extend through the lower ring so that the feet may be attached to the inner surface of the lower ring.

[0048] The flex member 216 is disposed at the second end 208 of the spoke 200. The flex member 216 has a width extending in the axial direction of the tire. The flex member 216 may be made of a polymer (e.g., polyurethane or rubber), a thin curved metal piece, or any other desired material or material combination. In the illustrated embodiment, the flex member 216 is configured as a cuboid and is arranged so that the end of the flex member 216 is aligned with the second end 208 of the spoke 200. In other alternative embodiments, the flex member may be arranged so that the end of the flex member is retracted relative to the second end of the spoke, or may be arranged so that the end of the flex member extends beyond the second end of the spoke. In other alternative embodiments, the flex member may be replaced by a mechanical pin joint (i.e., a hinge).

[0049] The flex member 216 includes a spoke-facing surface 218 and a ring-facing surface 220. The spoke-facing surface 218 of the flex 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 flex member 216 and the spoke 200 or between the flex member 216 and the upper ring 30 can be achieved using welding, brazing, soldering, adhesives, mechanical fasteners (e.g., bolts, rivets), keys / keyways, or any other desired arrangement. For example, the attachment can be provided by pouring polyurethane directly onto the spoke, with or without first coating the spoke with a primer.

[0050] The flex members 216 provide flexibility to the connection between the second ends 208 of the spokes 200 and the upper ring 30. This flexibility reduces the likelihood of high stresses being generated within the spokes 200, thereby increasing the robustness of the non-pneumatic tire 10. The connection provided by the feet 214 at the first ends 206 of the spokes 200 is more rigid than the flexible connection provided by the flex members 216.

[0051] In alternative embodiments, the flexure members may have shapes or configurations that are different than those specifically shown and described. In other alternative embodiments, additional structures or mechanisms may supplement the flexure members to attach the second ends of the spokes to the upper ring. In further alternative embodiments, the flexure members may be omitted and the second ends of the spokes may be directly attached to the upper ring. In these alternative embodiments, the second ends of the spokes may be directly attached to the inner surface of the upper ring, above the inner surface of the upper ring, or the spokes may extend through the upper ring so that the second ends may be attached to the outer surface of the upper ring.

[0052] The spoke 200 includes a toggle portion 222 located between the first end 206 and the second end 208. The toggle portion 222 has a first radius of curvature r1. According to an exemplary embodiment, the first radius of curvature r1 is 2 inches to 6 inches (5 cm to 15 cm). When attached to the upper ring 20 and the lower ring 30, the toggle portion 222 is concavely curved relative to the lower ring 20.

[0053] The transition portion 224 is disposed between the toggle 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 inches to 2 inches (0 cm to 5 cm). When attached to the upper ring 20 and the lower ring 30, the transition portion 224 is convexly curved relative to the lower ring 20. Therefore, relative to the single spoke 200, the toggle portion 222 and the transition portion 224 are concavely curved in opposite facing directions. In an alternative embodiment, the toggle portion and the transition portion are concavely (or convexly) curved in the same direction.

[0054] The foot 214 extends from the transition portion 224 to the first end 206 of the spoke 200. The first connecting portion 226 connects the transition portion 224 to the toggle portion 222, and the second connecting portion 228 connects the toggle portion 222 to the second end 208 of the spoke 200. In the illustrated embodiment, the first connecting portion 226 and the second connecting portion 228 are both linear. In alternative embodiments, the first connecting portion or the second connecting portion may be curved or have any other desired configuration. In other alternative embodiments, the transition portion and the foot may be omitted. In such alternative embodiments, the first end of the spoke will be located at the end of the first connecting portion.

[0055] The base plane p1 intersects the transition portion 224 and the second end 208 of the spoke 200 and serves as a reference for various dimensional aspects of the spoke 200. The angle between the base plane p1 and the second plane p2 extending 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 +0 degrees 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 inches to 25 inches (25 cm to 63.5 cm). Along the direction parallel to the base plane p1, the distance between the center of the transition portion 224 and the center of the first radius of curvature r1 of the elbow portion 222 is d2. According to an exemplary embodiment, the value of the distance d2 is 20% to 70% of the distance d1. The maximum distance between the elbow portion 222 and the base plane p1 along a direction perpendicular to the base plane p1 is d3. According to one example embodiment, distance d3 is 2 inches to 4 inches (5 cm to 10 cm).

[0056] Reference 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 (see also Figure 5 ).

[0057] A non-pneumatic tire constructed according to the above-described design parameters may provide a more robust assembly, particularly in terms of impact performance. Figure 7 and Figure 8 A tire is shown in an exemplary first condition. Figure 7 and Figure 8 As shown, according to a non-limiting example, in a first condition, the tire 10 is rolling on a flat surface while bearing a load (i.e., normal operation), the non-pneumatic tire 10 is deformed, but adjacent spokes 200 do not contact each other. The lack of contact between adjacent spokes 200 during normal operation is desirable to avoid generating unnecessary stress in the structure of the non-pneumatic tire 10.

[0058] It is expected that the non-pneumatic tire 10 will be exposed to high impact events during its life, such as striking a curb, a pothole, or other obstacle or road defect. During a high impact event, the non-pneumatic tire 10 may deform at a significantly higher level than the deformation that occurs during normal operation. An example of a high impact event is a non-pneumatic tire 10 striking a curb at a low speed (e.g., striking a 6-inch (15-cm) curb at 5 mph (8 km / h)). Another example of a high impact event is a non-pneumatic tire 10 striking a jump road defect at a high speed (e.g., striking a 1-inch (2.5-cm) jump at 70 mph (113 km / h). These are merely examples and are not meant to limit the definition of a "high impact event."

[0059] Fig. 9 and Fig.10 1 shows a tire in an exemplary second condition, the second condition being different from the first condition. Fig. 9 and Fig.10 As shown, according to a non-limiting example, in a second condition, the non-pneumatic tire 10 experiences a high impact event in which the tire rolls on an uneven surface. According to one non-limiting example, the uneven surface is a road defect that protrudes above the ground or is pressed into the ground by a distance of 3 inches (8 cm). According to another non-limiting example, the uneven surface is a road defect that protrudes above the ground or is pressed into the ground by a distance of 4.5 inches (11 cm). According to yet another non-limiting example, the uneven surface is a road defect that protrudes above the ground or is pressed into the ground by a distance of 6 inches (15 cm).

[0060] The non-pneumatic tire 10 responds to a high impact event by deforming so that adjacent spokes 200 contact one another. It has been surprisingly discovered that the contact between adjacent spokes 200 during a high impact event significantly reduces the stress experienced by each spoke 200, as compared to a non-pneumatic tire where the spokes do not contact one another during the high impact event. The reduction in stress in each spoke 200 is a result of the contact between adjacent spokes 200 because the contact distributes the load among the plurality of spokes 200. In other words, rather than a single spoke 200 absorbing the load generated by a high impact event, the plurality of spokes 200 share the same load, thereby reducing the peak load of any one single spoke 200.

[0061] In the illustrated embodiment, the non-pneumatic tire 10 is arranged and configured so that at least three adjacent spokes 200 are in contact with each other simultaneously during a high impact event, and the spokes 200 in contact with each other are located adjacent to the obstacle or road defect that caused the high impact event. In alternative embodiments, the non-pneumatic tire may be arranged and configured to have a lesser or greater number of adjacent spokes in contact with each other simultaneously during a high impact event. In other alternative embodiments, the adjacent spokes in contact with each other simultaneously may be located at any position along the circumferential direction of the tire (i.e., spaced apart from the obstacle or road defect that caused the high impact event).

[0062] Design parameters of the spokes 200 and other components of the non-pneumatic tire 10 may be varied to provide desired performance characteristics to the non-pneumatic tire 10. Preferably, these design parameters are selected so that contact between adjacent spokes 200 occurs before the spokes 200 begin to yield or experience any other form of damage.

[0063] The maximum distance d3 between the toggle portion 222 and the base plane p1 in a direction perpendicular to the base plane p1 affects the spoke stiffness and when contact between adjacent spokes 200 will occur. Increasing the distance d3 will physically move each spoke 200 closer to the adjacent spoke 200, thus causing contact between adjacent spokes 200 to occur relatively sooner. In addition, increasing the distance d3 will reduce the stiffness of the spokes 200, thereby increasing the amount of deflection for a given load, which increases the likelihood of contact between adjacent spokes 200. Reducing the distance d3 will have the opposite effect and will physically move each spoke 200 away from the adjacent spoke 200, thus causing contact between adjacent spokes 200 to occur relatively later. In addition, reducing the distance d3 will increase the stiffness of the spokes 200, thus reducing the amount of deflection for a given load, which reduces the likelihood of contact between adjacent spokes 200.

[0064] The distance d2 between the transition portion 224 and the center of the first radius of curvature r1 of the toggle portion 222 in a direction parallel to the base plane p1 affects when contact will occur with the adjacent spokes 200. When the distance d2 is a larger percentage of d1, this will cause contact between adjacent spokes 200 to occur relatively quickly. When the distance d2 is a smaller percentage of d1, this will cause contact between adjacent spokes 200 to occur relatively late.

[0065] The radius of curvature r1 of the toggle portion 222 affects when contact with adjacent spokes 200 will occur. Reducing the radius of curvature r1 will cause contact between adjacent spokes 200 to occur relatively late, while increasing the radius of curvature r1 will cause contact between adjacent spokes 200 to occur relatively soon. The spoke thickness t affects the stiffness of the spoke 200. Increasing the spoke thickness t will increase the stiffness of the spoke 200, while reducing the spoke thickness will reduce the stiffness of the spoke 200.

[0066] In addition, 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 reduces the tire stiffness, while reducing the distance d3 increases the tire stiffness. Therefore, it has been found that in order to meet the target value of tire stiffness, spokes with a larger thickness t should be combined with a larger distance d3, while spokes with a smaller thickness t should be combined with a smaller distance d3.

[0067] Fig.11 10 is a flow chart showing an exemplary method for manufacturing a non-pneumatic tire. At 1010, a lower ring and an upper ring are provided. The lower ring has a first diameter, and the upper ring has a second diameter greater 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. In addition, the spokes may be formed using a variety of composite manufacturing techniques (e.g., resin transfer molding and high pressure resin transfer molding). Other examples of methods for forming spokes include wet layup, prepreg lamination. Each spoke extends between a first end and a second end. A toggle portion is located between the first end and the second end, and a transition portion is located between the first end and the toggle portion. The toggle portion and the transition portion are concavely curved in opposite facing directions. A foot extends from the transition portion.

[0068] At 1030, a flex member is attached to the spokes. At 1040, the spokes are arranged into a first spoke set and a second spoke set axially spaced from the first spoke set. Additionally, a plurality of spokes of the first spoke set are arranged to be concavely curved relative to a first circumferential direction of the tire, and a plurality of spokes of the second spoke set are arranged to be convexly curved relative to the first circumferential direction of the tire.

[0069] At 1050, the lower ring is connected to the upper ring using the first spoke group and the second spoke group. The foot of each spoke is attached to the lower ring to connect the first end of each spoke to the lower ring. The flex member is attached to the upper ring to connect the second end of each spoke to the upper ring.

[0070] In alternative embodiments, the aforementioned steps may occur in an order different from that specifically described. In other alternative embodiments, the method may include a greater or lesser number of steps.

[0071] Fig.12 and Fig.12a Another embodiment of a spoke 1200 is shown. Fig.12 and Fig.12a The spokes of 1200 with Figures 1 to 10 The spokes 200 in FIG. 1 are substantially identical except for the differences described herein. Therefore, similar features will be identified by similar numbers increased by a factor of "1000". Figures 1 to 10 In the illustrated spoke 200, the second connecting portion 228 is linear. In contrast, Fig.12 and Fig.12a The spoke 1200 has a curved second connecting portion 1228 with a radius of curvature r3. Compared with the linear second connecting portion, Fig.12 and Fig.12a The curved second connecting portion 1228 in the spoke 1200 significantly enhances the self-supporting behavior. According to an exemplary embodiment, the radius of curvature r3 is 10 inches to 50 inches (25 cm to 127 cm).

[0072] In addition to the above Figures 1 to 10 In addition to the design parameters and resulting changes in performance characteristics discussed in the illustrated spoke 200, Fig.12 and Fig.12a The radius of curvature r3 of the curved second connection portion 1228 in the spoke 1200 can be varied to affect performance. The radius of curvature r3 of the curved second connection portion 1228 and the length l of the flexure member 1216 挠曲 The second connection portion 1228 is a curved second connection portion 1228 that is formed by a plurality of curved surfaces 1224 and 1225. The curved ... curved second connection portion 1228. The curved second connection portion 1228 is a curved second connection portion 1228 that is curved second connection portion 1228. The curved second connection portion 1228 is a curved second connection portion 1228 that is curved second connection portion 1228. The curved second connection portion 1228 is a curved second connection portion 1228 that is curved second connection portion 1228. The curved second connection portion 1228 is a curved second connection portion 1228 that is curved second connection portion 1228. The curved second connection portion 1228 is a curved second connection portion 1228 that is curved second connection portion 1228. The curved second connection portion 1228 is a curved second connection portion 1228 that is curved second connection portion 1228. The curved second connection portion 1228 is a curved second connection portion 1228 that is curved second connection portion 1

[0073] The length l of the flexure member 1216 挠曲This affects its ability to apply torque at the ends of the spokes 1200. This torque acts to straighten the curved second connecting portion 1228 when the tire is rolling under normal load or subjected to a high impact event. Therefore, it has been found that a curved second connecting portion 1228 having a smaller radius of curvature r3 is more effective than a curved second connecting portion 1228 having a longer length l 挠曲 The flexure member 1216 is optimally matched, and the curved second connecting portion 1228 having a larger radius of curvature r3 is optimally matched with the curved second connecting portion 1228 having a shorter length l 挠曲 The flexure member 1216 is optimally matched. In addition to the length l of the flexure member 1216 挠曲 In addition, the ability of the flexure members 1216 to apply torque on the spokes 1200 is also affected by the stiffness of the material used to make the flexure members 1216. Therefore, when using a softer material, it is desirable to provide a flexure member having a longer length l. 挠曲 flexure member 1216, and when using a harder material, it is desirable to provide a flexure member 1216 having a shorter length l 挠曲 Flexure member 1216.

[0074] 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, thereby significantly reducing the stress experienced by any single spoke in the non-pneumatic tire. Thus, the durability of the non-pneumatic tire is improved.

[0075] As described above, the foot 214 connects the first end 206 of the spoke 200 to the lower ring 20, and the flex member 216 connects the second end 208 of the spoke 200 to the upper ring 30. The flex member 216 provides a relatively flexible connection between the second end 208 of the spoke 200 and the upper ring 30, while the foot 214 provides a relatively rigid connection between the first end 206 of the spoke 200 and the lower ring 20.

[0076] According to this embodiment, the spoke 200 exhibits behavior similar to a cantilever beam, whereby the second end 208 deflects (i.e., moves) relative to the first end 206 as the tire 10 rolls and deforms. While this behavior is not inherently undesirable, it does cause the spoke 200 to compress, stretch, or shear, thereby generating stresses in the spoke 200. It has been found that the greatest stress occurs toward the first end 206 of the spoke, particularly near where the attachment between the foot 214 and the lower ring 20 ends, extending through the transition portion 224, and partially through the first connecting portion 226.

[0077] Figure 13-15 An alternative non-pneumatic tire is shown having spokes 2200 having features designed to attenuate the stresses described above. Figure 13-15 The embodiment shown in is substantially similar to Figure 1-6The embodiments shown in , except for any differences described herein. Therefore, similar features will be identified by similar numbers with the value "2000" increased.

[0078] Each spoke 2200 has a first surface 2210 and a second surface 2212, each extending between a first end 2206 and a second end 2208. A foot 2214 is provided toward the first end 2206 of the spoke 2200. A flex member 2216 is provided at the second end 2208 of the spoke 2200. The foot 2214 is attached to the lower ring 2020 to connect the first end 2206 of the spoke 2200 to the lower ring 2020, and the flex member 2216 is attached to the upper ring 2030 to connect the second end 2208 of the spoke 2200 to the upper ring 2030.

[0079] The toggle portion 2222 is disposed between the first end 2206 and the second end 2208. The toggle portion 2222 has a first radius of curvature r1. The transition portion 2224 is disposed between the toggle portion 2222 and the first end 2206, and the foot 2214 extends from the transition portion 2224 toward the first end 2206. The transition portion 2224 has a second radius of curvature r2. The first connecting portion 2226 connects the transition portion 2224 to the toggle portion 2222. The second connecting portion 2228 connects the toggle portion 2222 to the second end 2208 of the spoke 1200.

[0080] In this embodiment, the spokes 2200 are provided with auxiliary springs 2500. The auxiliary springs 2500 may be made of metal (e.g., steel, stainless steel, titanium), composite materials (e.g., carbon fiber reinforced polymer, glass reinforced polymer), or any other desired material or combination of materials. The auxiliary springs 2500 may be provided with reinforcements (not shown) or other features that affect the stiffness of the auxiliary springs. In the illustrated embodiment, the auxiliary springs 2500 are separate, discrete components from the spokes 2200. In alternative embodiments, the auxiliary springs may be formed integrally with the spokes, for example, by folding the ends of the spokes back onto themselves.

[0081] The auxiliary spring 2500 extends between a first end 2502 and a second end 2504 and has a substantially rectangular cross-section including a first surface 2506 and a second surface 2508 that are opposed to each other. hs The width w of the auxiliary spring is the total distance between the first end 2502 and the second end 2504 measured along the longitudinal axis of the auxiliary spring 2500. hs It refers to the auxiliary spring 2500 along the transverse direction of its length l hs The distance between the first edge 2507 and the second edge 2509 in the extending direction. Auxiliary spring thickness t hsRefers to the distance between the first surface 2506 and the second surface 2508. In the illustrated embodiment, the auxiliary spring thickness t hs is constant between the first end 2502 and the second end 2504 and is equal to the thickness t1 of the spoke 2000. In addition, the auxiliary spring width w of the auxiliary spring hs The thickness or width of the auxiliary spring may vary between the first end 2502 and the second end 2504, or the auxiliary spring and the spoke may have different thicknesses or widths. In other alternative embodiments, the auxiliary spring may have any desired cross-sectional shape or may have a combination of different cross-sectional shapes.

[0082] The auxiliary spring 2500 has a curved portion 2510 between the first end 2502 and the second end 2504. In the illustrated embodiment, the curved portion 2510 has a radius of curvature r3 that is substantially equal to the radius of curvature r2 of the transition portion 2224 of the spoke 2000. In alternative embodiments, the curved portion may have a radius of curvature that is different from the radius of curvature of the transition portion.

[0083] The first arm portion 2512 connects the first end 2502 to the curved portion 2510. The second arm portion 2514 connects the second end 2504 to the curved portion. In the illustrated embodiment, both the first arm portion 2512 and the second arm portion 2514 are linear. In alternative embodiments, the first arm portion or the second arm portion can be curved or have any other desired arrangement.

[0084] like Fig.15 , the first surface 2506 of the helper spring 2500 is attached to the second surface 2212 of the spoke 2200 along a bonding area 2516. The helper spring 2500 may be attached to the spoke 2200 using welding, brazing, soldering, adhesives, mechanical fasteners, or any other desired attachment method. According to this embodiment, the helper spring 2500 is located radially above the spoke 2200 (i.e., the radial distance between the helper spring and the lower ring is greater than the radial distance between the spoke and the lower ring).

[0085] In the illustrated embodiment, the bonding region 2516 starting at the first end 2502 of the auxiliary spring 2500 has a bonding length l b , the combined length is along the length l of the auxiliary spring 2500 hs 33% and the entire width w of the auxiliary spring hs The portion of the auxiliary spring 2500 that is not coupled to the spoke 2200 is referred to as a free portion 2571 and has a free length l fIn alternative embodiments, the bonded region may extend along 20%-100% of the length of the auxiliary spring or 20%-100% of the width of the auxiliary spring. In other alternative embodiments, the bonded region may not begin at the first end of the auxiliary spring, but rather there may be an unbonded region of any desired length before the bonded region begins. In further alternative embodiments, the bonded regions may be intermittently disposed along the length of the auxiliary spring.

[0086] The assist spring 2500 is arranged relative to the spoke 2200 such that the curved portion 2510 of the assist spring 2500 is adjacent to and nested with the transition portion 2224 of the spoke 2200. In the illustrated embodiment, the first arm portion 2512 of the assist spring 2500 is sized and configured such that the first end 2502 of the assist spring 2500 is aligned with the first end 2206 of the spoke 2200, and the second arm portion 2514 is sized and configured such that the second end 2504 of the assist spring 2500 is positioned slightly less than halfway between the transition portion 2224 and the toggle portion 2222 of the spoke 2200. In alternative embodiments, the first arm portion or the second arm portion may be sized and configured to position the first end or the second end of the assist spring at any desired position relative to the spoke.

[0087] It has been found that the provision of the auxiliary spring 2500 significantly reduces the maximum stress that occurs during compression of the spoke 2200. The design parameters of the auxiliary spring 2500, the spoke 2200, and other components of the non-pneumatic tire can be changed to provide the desired performance characteristics to the non-pneumatic tire. For example, increasing the length of the second arm portion 2514 of the auxiliary spring 2200 reduces the maximum stress that occurs in the spoke 2200, but may produce a greater contact pressure between the auxiliary spring 2500 and the spoke 2200. For another example, increasing the thickness of the auxiliary spring 2500 reduces the maximum stress that occurs in the spoke 2200, but may increase the contact pressure between the auxiliary spring 2500 and the spoke 2200. In addition, increasing the thickness of the auxiliary spring 2500 may increase the stress in the bonding area 2516.

[0088] In the illustrated embodiment, the spoke arrangement includes only a single helper spring 2500. In alternative embodiments, the spoke arrangement may include multiple helper springs. In one exemplary embodiment, each of the multiple helper springs is identical to one another. In other exemplary embodiments, each of the multiple helper springs may have a different length, thickness, width, or be made of a different material or have a different reinforcement, or may have other design variables selected to provide the non-pneumatic tire with desired performance characteristics.

[0089] In addition to the design variables discussed above, the second end 2504 of the assist spring 2500 may be provided in a variety of planar shapes or with specific edge arrangements to further tune the spoke 2200 and provide desired non-pneumatic tire performance characteristics. Fig.16a -c shows three variations of the planar shape of the second end 2502 of the auxiliary spring 2500, and Fig.17a -c is a graph showing the performance metrics associated with each design variation. Fig.16a In the embodiment, the second end 2502 of the auxiliary spring 2500 is square in plan view. It has been found that this square shape allows the entire auxiliary spring 2500 to evenly support the spoke 2200 and obtain Fig.17a The performance metrics shown and described in FIG. 22 are shown and described in FIG. 22. In addition, it has been found that the square shape provides the greatest stress reduction in the spokes 2200. Fig.16b In FIG. 2 , the second end 2502 of the auxiliary spring 2500 has a chamfered corner in plan view. It has been found that using angled corners rather than square corners reduces the contact pressure between the auxiliary spring 2500 and the spoke 2200 and provides a better fit. Fig.17b In addition, it has been found that the diagonal shape can improve the fatigue performance of the spoke 2200. Fig.16c In FIG. 2 , the second end 2502 of the auxiliary spring 2500 is oval in plan view. It has been found that this oval shape provides a reduced stress reduction similar to a square end, while also reducing contact pressure similar to a chamfered corner design, and provides a Fig.17c The performance metrics shown and described in .

[0090] Figures 18a-18d Four variations of the shape of the edge of the second end 2502 of the auxiliary spring 2500 are shown. Here, "edge" refers to the surface of the auxiliary spring 2500 that connects the first surface 2506 to the second surface 2508 at the second end 2502. Fig.18a In the embodiment, the second end 2502 of the auxiliary spring 2500 has a chamfered upper portion and a chamfered lower portion and a straight portion extending therebetween. When attached to the spoke 2200, the lower portion is adjacent to the second surface 2212 of the spoke 2200. This arrangement can reduce local contact stress or reduce the tendency to wear damage by reducing local contact stress. Fig.18b In the embodiment, the second end 2502 of the auxiliary spring 2500 has a rounded upper portion and a rounded lower portion and a straight portion extending therebetween. Compared with the chamfered design described above, this arrangement can even further reduce the tendency for wear damage to occur. Fig.18c In the embodiment, the upper and lower portions are chamfered so that the entire second end 2502 is angled. In other words, there is no straight portion between the chamfered upper and lower portions. This arrangement can provide Fig.18aSimilar local stresses and similar reduction in wear damage are achieved with the arrangement shown in . Fig.18d In the embodiment of the present invention, the upper and lower portions are rounded so that the entire second end 2502 is curved. In other words, there is no straight portion between the rounded upper and lower edges. This arrangement can be even more Fig.18b The arrangement shown in further reduces stress.

[0091] Fig.19 Show Figure 12-14 The spoke arrangement of FIG. 18 is different from Figure 12-14 The spoke arrangements in the are substantially similar, except for any differences described herein. Therefore, similar features will be identified by similar numbers with the value "1000" increased.

[0092] according to Fig.19 In the variation shown in , the second surface 3508 of the auxiliary spring 3500 is attached to the first surface 3210 of the spoke 3200, and the second end 3208 of the spoke 3200 is attached to the lower ring 3020 by attaching the first surface 3506 of the auxiliary spring 3500 to the lower ring 3020. According to this embodiment, the auxiliary spring 3500 is radially positioned below the spoke 3200 (i.e., the radial distance between the auxiliary spring and the lower ring is less than the radial distance between the spoke and the lower ring). Positioning the auxiliary spring 3500 radially below the spoke 3200 can improve load carrying efficiency due to tension or shear forces. In another variation (not shown), two auxiliary springs can be attached to the spoke, with a first auxiliary spring attached to the second surface of the spoke and a second auxiliary spring attached to the first surface of the spoke (i.e., one auxiliary spring is located above the spoke and one auxiliary spring is located below the spoke).

[0093] Fig. 20 Show Figure 12-14 Another variation of the spoke arrangement. Fig. 20 The arrangement is basically similar to Figure 12-14 The arrangement of the present invention is different from any differences described herein. Therefore, similar features will be identified by similar numbers with the value "4000" increased.

[0094] according to Fig. 20In the variation shown, a buffer 4519 is disposed between the auxiliary spring 4500 and the spoke 4200, specifically between the free portions 4517 of the spoke 4200 adjacent to the bonding area 4516. The buffer 4519 is arranged and constructed to minimize the occurrence of damage caused by stress due to any contact between the auxiliary spring 4500 and the spoke 4200. In the illustrated embodiment, the buffer 4500 is a separate component from both the auxiliary spring 4500 and the spoke 4200, and can be made of plastic, metal, carbon fiber reinforced polymer, glass reinforced polymer, ceramic, or any other desired material or combination of materials. The buffer 4519 can be attached to the auxiliary spring 4500 or the spoke 4200 using adhesives, mechanical fasteners, brazing, soldering, welding, or any other desired arrangement. In alternative embodiments, the buffer can be directly integrated into the auxiliary spring or the spoke. In other alternative embodiments, the buffer can be a coating applied to the spoke or auxiliary spring. In other embodiments, the buffer can be a thin air gap. According to one example, the air gap is 0.0020 inches (0.05 mm) thick.

[0095] Although different embodiments and variants have been shown and described in a number of drawings, the disclosed features are not exclusive to each described embodiment. Rather, various features from different embodiments or variants may be combined as desired.

[0096] To the extent that the terms "including" or "having" are used in the specification or claims, they are intended to be inclusive in a manner similar to how the term "comprising" is understood when used as a transitional word in a claim. Furthermore, to the extent that the term "or" is employed (e.g., A or B), the term is intended to mean "A or B or both." When applicants intend to indicate "only A or B but not both," then the term "only A or B but not both" will be employed. Thus, the use of the term "or" herein is inclusive and does not have an exclusive use. See Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d. Ed. 1995). In addition, to the extent the terms "in" or "into" are used in the specification and claims, the terms are intended to additionally mean "on" or "onto." Furthermore, to the extent the term "connected" is used in the specification or claims, the term is intended to mean not only "directly connected to," but also "indirectly connected to," such as connected through another component or components.

[0097] Although the present application has been illustrated by the description of its embodiments, and although the embodiments have been described in considerable detail, the applicant does not intend that the scope of the appended claims be constrained to or in any way limited to such details. Additional advantages and modifications will be apparent to those skilled in the art. Therefore, in its broader aspects, the present application is not limited to the specific details, representative devices and methods, and illustrative examples shown and described. Therefore, such details may be deviated from without departing from the spirit or scope of the applicant's overall inventive concept.

Claims

1. A non-pneumatic tire, comprising: a lower ring having a first diameter, an upper ring having a second diameter, the upper ring being substantially coaxial with the lower ring; as well as A support structure connecting the lower ring to the upper ring, the support structure being comprised of a plurality of spokes arranged into a first spoke set and a second spoke set axially spaced from the first spoke set, each of the plurality of spokes comprising: connected to a first end of the lower ring; connected to the second end of the upper ring; a transition portion between the first end and the second end; and An assist spring is nested with the transition portion of the spoke.

2. The non-pneumatic tire of claim 1, wherein the auxiliary spring is located radially above the spoke.

3. The non-pneumatic tire of claim 1, wherein the auxiliary spring is located radially below the spoke.

4. The non-pneumatic tire of claim 1, wherein the auxiliary spring includes a curved portion between the first end and the second end, and wherein a radius of curvature of the curved portion is substantially equal to a radius of curvature of the transition portion of the spoke.

5. The non-pneumatic tire of claim 1, wherein the auxiliary spring is attached to the spoke along a bonding area, the bonding area extending along 20% ​​to 100% of the length of the auxiliary spring.

6. The non-pneumatic tire of claim 1 , wherein the spoke further comprises a toggle portion between the transition portion and the second end, and wherein the auxiliary spring comprises a first end and a second end, the first end of the auxiliary spring being aligned with the first end of the spoke, the second end of the auxiliary spring being located at a position less than halfway between the transition portion and the toggle portion of the spoke.

7. The non-pneumatic tire of claim 1, wherein the auxiliary spring includes a curved portion between a first end and a second end, the curved portion being adjacent to the transition portion of the spoke, the second end being one of square, chamfered, and oval in plan view.

8. The non-pneumatic tire of claim 1, wherein the auxiliary spring includes a curved portion between a first end and a second end, an edge of the second end being one of square, chamfered, and rounded.

9. The non-pneumatic tire of claim 1, wherein at least one spoke includes a bumper between the auxiliary spring and the spoke.

10. The non-pneumatic tire of claim 9, wherein the bumper is made of at least one of plastic, metal, carbon fiber reinforced polymer, glass reinforced polymer, and ceramic.

11. A method of manufacturing a non-pneumatic tire, the method comprising the steps of: providing a lower ring having a first diameter and an upper ring having a second diameter greater than the first diameter; forming a plurality of spokes, each spoke extending between a first end and a second end, each spoke having a transition portion between the first end and the second end, each spoke having an auxiliary spring nested with the transition portion; arranging the plurality of spokes into a first spoke group and a second spoke group axially spaced from the first spoke group; as well as The lower ring is connected to the upper ring using the first and second spoke sets.

12. The method of manufacturing a non-pneumatic tire of claim 11, wherein forming the plurality of spokes involves at least one of hot stamping, cold forming, extrusion, and composite layup.

13. The method for manufacturing a non-pneumatic tire according to claim 11, further comprising the steps of: The end portion forming the auxiliary spring has one of a square shape, a chamfered shape, and an oval shape in a plan view.

14. The method for manufacturing a non-pneumatic tire according to claim 11, further comprising the steps of: The end portion forming the auxiliary spring has one of a square end portion, a chamfered end portion, and a rounded end portion.

15. The method of manufacturing a non-pneumatic tire according to claim 11, further comprising providing a buffer between the spoke and the auxiliary spring.

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