Mounting arrangement for a self-supporting spoke structure of a 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 support structure is comprised of a plurality of spokes. The support structure is arranged and configured such that adjacent spokes of the plurality of spokes contact one another upon occurrence of a high impact event.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a non-pneumatic tire. More particularly, 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

[0002] Various tire constructions have been developed that enable a tire to travel in an uninflated or underinflated state. Non-pneumatic tires do not require inflation, while “run-flat tires” can continue to travel at relatively high speeds for extended periods of time after being punctured and partially or completely deflated. Non-pneumatic tires can include a support structure, such as spokes or webs, that connect a lower ring to an upper ring. In some non-pneumatic tires, a circumferential tread can be attached to the upper ring of the tire.

[0003] The circumferential tread can include a tread band. The tread band can be a single layer of material or a multi-layer band. Such a tread band can 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 tensile resistance member.

[0004] Tire designs for both pneumatic and non-pneumatic tires involve 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 a curb, pothole, or other obstacle or road defect. SUMMARY

[0005] In one embodiment, a non-pneumatic tire includes a lower ring provided with a plurality of scallop notches. Each of the plurality of scallop notches has a first curved surface. An upper ring is substantially coaxial with the lower ring. A support structure connects the lower ring to the upper ring. The support structure is comprised of a plurality of spokes. Each of the plurality of spokes includes a first end connected to the lower ring and a second end connected to the upper ring. Each of the plurality of spokes further includes a first surface and a second surface facing oppositely from the first surface. Each of the first surface and the second surface extends between the first end and the second end. A foot portion is disposed toward the first end of the spoke. The first surface of the spoke at the foot portion is a second curved surface. The second curved surface is attached to the first curved surface of one of the plurality of scallop notches 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 scallop notches are formed on the lower ring. Each of the plurality of scallop notches has a first curved surface. A plurality of spokes are formed, each having a first surface and a second surface facing oppositely from the first surface. The first and second surfaces each extend between a first end and a second end. Forming the plurality of spokes includes providing a foot portion toward the first end of the spoke. The first surface of the spoke at the foot portion is a second curved surface. The lower ring is connected to the upper ring by a first set of spokes and a second set of spokes. Connecting the lower ring to the upper ring includes attaching the second curved surface of the spoke at the foot portion to the first curved surface of one of the plurality of scallop notches to connect the first end of the spoke to the lower ring and to connect the second end of the spoke to the upper ring.

[0007] In yet another embodiment, a non-pneumatic tire includes a lower ring having a first radius of curvature. The lower ring is provided with a plurality of scallop notches. Each scallop notch includes a first curved surface having a second radius of curvature. An upper ring is substantially coaxial with the lower ring. A support structure connects the lower ring to the upper ring. The support structure is comprised of a plurality of spokes. Each spoke extends between a first end and a second end and includes a first surface and a second surface facing oppositely from the first surface. Each of the first and second surfaces extends between the first end and the second end. The spoke is provided with a foot portion toward the first end. The first surface of the spoke at the foot portion is a second curved surface having a third radius of curvature. Each of the first and second radii of curvature is different from the third radius of curvature. BRIEF DESCRIPTION OF DRAWINGS

[0008] In the drawings, which are not intended to be to scale, and which are provided merely for illustrative purposes, certain ones of the elements are shown exaggerated in size or in different positions for purposes of explanation, and are not necessarily drawn to scale. In addition, not all of the elements of the structures illustrated in the figures can be required to practice the application, because, in certain instances, some of the elements are enough on their own to fulfill the purposes of the application. Moreover, the application can cover any and all modifications, variations, or equivalents of the elements of the structures due to the metes of the application hereto.

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

[0010] Figure 2 is Figure 1 is another side view of a non-pneumatic tire of

[0011] Figure 3 is Figure 1 is a cross-sectional view along 3-3 of

[0012] Figure 4 is Figure 1 is a detail view of area A of

[0013] Figure 5 is Figure 1 a detail view of area A, with some features removed for clarity,

[0014] Figure 6 is Figure 1 a detail view of a single spoke used in the non-pneumatic tire of

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

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

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

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

[0019] Figure 11 is a flow chart showing a method of manufacturing the non-pneumatic tire of Figure 1

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

[0021] Figure 12a is an end view of the spoke of Figure 12 along I-I,

[0022] Figure 13 is a side view of the non-pneumatic tire showing the effect of manufacturing tolerances in the spoke before the spoke is attached to the upper ring at the second end of the spoke,

[0023] Figure 14 is a side view of the non-pneumatic tire of Figure 13 after the second end of the spoke is attached to the upper ring,

[0024] Figure 15 is a partial view of another embodiment of a non-pneumatic tire,

[0025] Figure 16 is a detail view of a single spoke used in the non-pneumatic tire of Figure 15

[0026] ​​Figure 17 is a partial side view of another embodiment of a non-pneumatic tire,

[0027] Figure 18 is a partial perspective view of a non-pneumatic tire of Figure 17

[0028] Figure 19 is another partial perspective view of a non-pneumatic tire of Figure 17

[0029] Figure 20 is a partial side view of yet another embodiment of a non-pneumatic tire, and

[0030] Figure 21 is a detail view of a single spoke of a non-pneumatic tire of Figure 20 DETAILED DESCRIPTION

[0031] The following includes definitions of selected terms employed herein. The definitions include various examples or forms of components that fall within the scope of a term and that can be used in implementation. Not all of the examples are intended to be limiting in nature. Both the singular and plural forms of terms can be within the definitions.

[0032] “Axial” and “axially” refer to a direction parallel to the axis of rotation of the tire.

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

[0034] “Radial” and “radially” refer to a direction perpendicular to the axis of rotation of the tire.

[0035] “Tread” as used herein refers to the portion of the tire that contacts the road or ground under normal inflation and normal load conditions.

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

[0037] ​​​Direction is defined in this document with reference to the tire's axis of rotation. The terms "upward" and "upwardly" refer to the general direction toward the tire's tread, while "downward" and "downwardly" refer to the general direction toward the tire's axis of rotation. Therefore, when relative directional terms such as "upper" and "lower" or "top" and "bottom" are used in conjunction with other elements, the "upper" or "top" element is spatially closer to the tread than the "lower" or "bottom" element. Furthermore, when relative directional terms such as "above" or "below" are used in conjunction with other elements, if one element is "above" another element, it means that the element is closer to the tread than the other elements.

[0038] The terms "inward" and "inner" refer to the general direction toward the equatorial plane of the tire, while "outward" and "outer" refer to the general direction away from the equatorial plane of the tire and toward the sidewall of the tire. Therefore, 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 pneumatic tire 10 is shown. The pneumatic tire 10 is merely an illustrative example and is not intended to be limiting. In the illustrated embodiment, the 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 of polymers reinforced with glass or carbon fibers, 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 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 may be made of a polymeric material, an elastomeric material, a metal, a composite made 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 belt 72 and a tread layer 74. The tread belt 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 belt may include a filament assembly.

[0042] In the illustrated embodiment, tread belt 72 is shown as a single layer. In an alternative embodiment, the tread belt may be a multi-layer belt. Such a multi-layer tread belt may include one or more layers of substantially non-stretchable material. The layer may be formed from sheet material, cord material, filament material, or any other desired arrangement. In other alternative embodiments, the multi-layer tread belt may include layers of stretchable material, such as an elastomer. According to one example embodiment, the tread belt may include a pair of non-stretchable layers separated by layers of stretchable material. In yet another alternative embodiment, the tread belt may include a belt referred to as a shear belt, shear element, or thin annular high-strength belt element.

[0043] A 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 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 may include more than two axially spaced spoke groups.

[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 an alternative embodiment, the space between the first and second spoke groups can be larger or smaller, or the first and second spoke groups can be arranged with no space between them. When from Figure 1 When viewed from the angle shown, each spoke 200 of the first spoke group 202 is substantially convex relative to the clockwise circumferential direction of the non-pneumatic tire 10, and each spoke of the second spoke group 204 is substantially concave relative to the clockwise circumferential direction of the non-pneumatic tire 10.

[0045] All spokes 200 of the first spoke group 202 and the second spoke group 204 have the same construction. Therefore, the description of spokes 200 will refer to Figure 6 The single spoke 200 shown is constructed. The spoke 200 may be made of a metal such as steel or aluminum, a polymer such as polyester or nylon, a composite of a polymer reinforced with glass fiber or carbon fiber, or any other desired material or combination of materials. 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 comprising a first surface 210 and a second surface 212 facing oppositely from 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 can vary between the first end and the second end. For example, the spoke can have relatively thicker portions at the first and second ends and a relatively thinner portion between the ends. In other alternative embodiments, the spoke can have any desired cross-sectional shape (e.g., circular, diamond, hexagonal, etc.) or can 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 at the foot 214 is attached to the outer surface 24 of the lower ring 20 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 with welding, brazing, soldering, adhesive, mechanical fasteners (e.g., bolts, rivets), key / keyway, or any other desired arrangement. In the illustrated embodiment, the foot 214 is substantially straight and the entire length (dimension of the foot extending in the circumferential direction of the tire) and the entire width (dimension of the foot extending in the axial direction of the tire) is fixed to the outer surface 24 of the lower ring 20. In alternative embodiments, the foot can be a separate component that is 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 foot can be attached under the outer surface of the lower ring, or the spoke can extend through the lower ring such that the foot can be attached to the inner surface of the lower ring.

[0048] A flex member 216 is provided at the second end 208 of the spoke 200. The flex member 216 has a width that extends in the axial direction of the tire. The flex member 216 can be made of a polymer (e.g., polyurethane or rubber), a thin, curved piece of metal, or any other desired material or combination of materials. In the illustrated embodiment, the flex member 216 is provided as a rectangular cuboid and is arranged such that the ends of the flex member 216 are aligned with the second end 208 of the spoke 200. In other alternative embodiments, the flex member can be arranged such that the ends of the flex member are indented relative to the second end of the spoke, or can be arranged such that the ends of the flex member extend beyond the second end of the spoke. In further alternative embodiments, the flex member can be replaced with 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 with welding, brazing, soldering, adhesive, mechanical fasteners (e.g., bolts, rivets), key / keyway, or any other desired arrangement. For example, the attachment can be provided by direct casting of polyurethane onto the spoke, with or without first priming the spoke.

[0050] The flex member 216 provides flexibility for the connection between the second end 208 of the spoke 200 and the upper ring 30. This flexibility reduces the likelihood of high stress being generated within the spoke 200, thereby improving the robustness of the non-pneumatic tire 10. The connection provided by the foot 214 at the first end 206 of the spoke 200 is more rigid compared to the flexible connection provided by the flex member 216.

[0051] In alternative embodiments, the flex member can have a shape or configuration that is different from the specific shapes or configurations shown and described. In other alternative embodiments, additional structures or mechanisms can supplement the flex member to attach the second end of the spoke to the upper ring. In further alternative embodiments, the flex member can be omitted, and the second end of the spoke can be attached directly to the upper ring. In these alternative embodiments, the second end of the spoke can be attached directly to the inner surface of the upper ring, above the inner surface of the upper ring, or the spoke can extend through the upper ring such that the second end can be attached to the outer surface of the upper ring.

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

[0053] A transition portion 224 is disposed between the knuckle portion 222 and the first end 206. The transition portion 224 has a second radius of curvature r2. According to one example embodiment, the second radius of curvature r2 is 0 inches to 2 inches (0 cm to 5 cm). When attached to the upper ring 30 and the lower ring 20, the transition portion 224 is convexly curved relative to the lower ring 20. Thus, relative to the single spoke 200, the knuckle portion 222 and the transition portion 224 are concavely curved in opposite facing directions. In alternative embodiments, the knuckle 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. A first connecting portion 226 connects the transition portion 224 to the knuckle portion 222, and a second connecting portion 228 connects the knuckle portion 222 to the second end 208 of the spoke 200. In the illustrated embodiment, both the first connecting portion 226 and the second connecting portion 228 are linear. In alternative embodiments, either the first connecting portion or the second connecting portion can be curved or have any other desired configuration. In other alternative embodiments, the transition portion and the foot can be omitted. In such alternative embodiments, the first end of the spoke would be at the end of the first connecting portion.

[0055] A base plane pi 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 pi and a second plane p2 that extends at the transition portion 224 tangentially to the outer surface 24 of the lower ring 20 is a. According to one example embodiment, the angle a is +0 degrees to 20 degrees. The distance between the transition portion 224 and the second end 208 of the spoke 200 in a direction parallel to the base plane pi is di. According to one example embodiment, the distance di is 10 inches to 25 inches (25 cm to 63.5 cm). The distance between the center of the transition portion 224 and the center of the first radius of curvature ri of the knuckle portion 222 in a direction parallel to the base plane pi is d2. According to one example embodiment, the distance d2 is 20% to 70% of the distance di. The maximum distance between the knuckle portion 222 and the base plane pi in a direction perpendicular to the base plane pi is d3. According to one example embodiment, the distance d3 is 2 inches to 4 inches (5 cm to 10 cm).

[0056] Referring to Figure 10 , the transition portion 224 of one spoke 200 is separated from the first end 206 of an adjacent spoke 200 by a first separation distance si. The second ends 208 of the adjacent spokes 200 are separated from each other by a second separation distance s2 (see also Figure 5 ).

[0057] A non-pneumatic tire constructed according to the design parameters described above can provide a more robust assembly, particularly with respect to impact performance. Figure 7 and Figure 8 A tire is shown in an example first condition. As Figure 7 and Figure 8 shown, according to non-limiting examples, in the first condition, the tire 10 is rolling on a flat surface while carrying a load (i.e., normal operation), the non-pneumatic tire 10 is deformed, but the adjacent spokes 200 are not in contact with each other. The absence of contact between the adjacent spokes 200 during normal operation is desirable to avoid creating unnecessary stresses 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 lifetime, such as hitting a curb, pothole, or other obstacle or road defect. During a high impact event, the non-pneumatic tire 10 can deform at a significantly higher level than the deformations that occur during normal operation. One example of a high impact event is the non-pneumatic tire 10 hitting a curb at low speed (e.g., hitting a 6 inch (15 cm) curb at 5 miles per hour (8 kilometers per hour)). Another example of a high impact event is the non-pneumatic tire 10 hitting an upward-jumping road defect at high speed (e.g., hitting a 1 inch (2.5 cm) upward jump at 70 miles per hour (113 kilometers per hour)). These are merely examples and are not meant to limit the definition of a “high impact event.”

[0059] Figure 9 and Figure 10 The tire is shown in an example second condition, which is different than the first condition. As shown in FIG. 2, according to a non-limiting example, in the second condition, the non-pneumatic tire 10 experiences a high impact event in which the tire rolls over 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). Figure 9 and Figure 10 As shown in FIG. 2, according to a non-limiting example, in the second condition, the non-pneumatic tire 10 experiences a high impact event in which the tire rolls over 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 the high impact event by deforming such that adjacent spokes 200 contact each other. It has been surprisingly discovered that the 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 in which the spokes do not contact each other during a high impact event. The reduction in stress in the individual spokes 200 is a result of the contact between adjacent spokes 200 because the contact distributes the load among multiple spokes 200. In other words, rather than a single spoke 200 absorbing the load created by the high impact event, multiple spokes 200 share the same load, thus reducing the peak load of any one single spoke 200.

[0061] 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 spokes 200 that contact each other are positioned adjacent to the obstacle or road defect that caused the high impact event. In alternative embodiments, the non-pneumatic tire can be arranged and configured to have a fewer or greater number of adjacent spokes that contact each other simultaneously during a high impact event. In other alternative embodiments, the adjacent spokes that contact each other simultaneously can be positioned at any location 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 can be varied to provide the non-pneumatic tire 10 with desired performance characteristics. Preferably, these design parameters are selected such 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 knuckle portion 222 and the base plane pi in a direction perpendicular to the base plane pi 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 spokes 200, thus causing contact between adjacent spokes 200 to occur relatively sooner. Additionally, increasing the distance d3 will decrease the stiffness of the spokes 200, thus increasing the amount of deflection for a given load, which increases the likelihood of contact between adjacent spokes 200. Decreasing the distance d3 will have the opposite effect and will physically move each spoke 200 away from the adjacent spokes 200, thus causing contact between adjacent spokes 200 to occur relatively later. Additionally, decreasing the distance d3 will increase the stiffness of the spokes 200, thus decreasing the amount of deflection for a given load, which decreases 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 knuckle portion 222 in a direction parallel to the base plane pi affects when contact with an adjacent spoke 200 will occur. When the distance d2 is a larger percentage of di, this will cause contact between adjacent spokes 200 to occur relatively sooner. When the distance d2 is a smaller percentage of di, this will cause contact between adjacent spokes 200 to occur relatively later.

[0065] The radius of curvature r1 of the knuckle portion 222 affects when contact with an adjacent spoke 200 will occur. Decreasing the radius of curvature r1 will cause contact between adjacent spokes 200 to occur relatively later, while increasing the radius of curvature r1 will cause contact between adjacent spokes 200 to occur relatively sooner. The spoke thickness t affects the stiffness of the spokes 200. Increasing the spoke thickness t will increase the stiffness of the spokes 200, while decreasing the spoke thickness will decrease the stiffness of the spokes 200.

[0066] Additionally, it has been found that the vertical stiffness of the tire is affected by the combination of spoke thickness t and distance d3. Increasing distance d3 decreases tire stiffness, while decreasing distance d3 increases tire stiffness. Thus, it has been found that, in order to meet target values of tire stiffness, spokes having a greater thickness t should be combined with a greater distance d3, while spokes having a lesser thickness t should be combined with a lesser distance d3.

[0067] Figure 11 is a flowchart illustrating an example method of 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 that is greater than the first diameter. At 1020, a plurality of spokes are formed. The spokes can be formed using hot stamping, cold forming, extrusion, rolling, bending, or any other desired method. Additionally, the spokes can be formed using a variety of composite manufacturing techniques, such as resin transfer molding and high pressure resin transfer molding. Other examples of methods for forming the spokes include wet layup, prepreg layup. Each spoke extends between a first end and a second end. A knuckle portion is located between the first end and the second end, and a transition portion is located between the first end and the knuckle portion. The knuckle portion and the transition portion are concavely curved in opposite facing directions. A foot portion extends from the transition portion.

[0068] At 1030, a flexure member is attached to the spokes. At 1040, the spokes are arranged into a first spoke set and a second spoke set that is axially spaced apart from the first spoke set. Further, the plurality of spokes of the first spoke set are arranged to be concavely curved relative to a first circumferential direction of the tire, and the 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 set and the second spoke set. The foot portion of each spoke is attached to the lower ring to connect the first end of each spoke to the lower ring. The flexure member is attached to the upper ring to connect the second end of each spoke to the upper ring.

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

[0071] Figure 12 and Figure 12a Another embodiment of a spoke 1200 is illustrated. Figure 12 and Figure 12a The spoke 1200 of Figures 1 to 10 is substantially identical to the spoke 200 in Figures 1 to 10 In the illustrated spoke 200, the second connection portion 228 is linear. In contrast, Figure 12 andFigure 12a The spokes 1200 have a curved second connecting portion 1228 with a radius of curvature r3. Compared to a linear second connecting portion, Figure 12 and Figure 12a The curved second connecting portion 1228 in the spokes 1200 significantly enhances the self-supporting behavior. According to one example implementation, the radius of curvature r3 is 10 inches to 50 inches (25 cm to 127 cm).

[0072] In addition to the above, regarding Figures 1 to 10 In addition to the changes in design parameters and performance characteristics discussed in the wheel spoke 200 diagram, Figure 12 and Figure 12a The radius of curvature r3 of the curved second connecting portion 1228 in the spoke 1200 can be varied to affect performance. The radius of curvature r3 of the curved second connecting portion 1228 and the length l of the flexural member 1216 are also considered. 挠曲 The interaction affects the self-supporting performance. The smaller radius of curvature r3 of the curved second connecting portion 1228 reduces self-support, thus increasing stress during high impact events. The larger radius of curvature r3 of the curved second connecting portion 1228 increases self-support, thus reducing stress during high impact events. However, this stress reduction occurs at most slightly. As the radius of curvature r3 increases (the limit is that the radius of curvature r3 equals infinity, resulting in a straight second connecting portion), the effectiveness of self-supporting begins to decrease again.

[0073] The length l of the flexural member 1216 挠曲 This affects its ability to apply torque at the end of the spokes 1200. This torque is used to straighten the bent second connecting portion 1228 when the tire rolls under normal load or experiences a high-impact event. Therefore, it has been found that a bent second connecting portion 1228 with a smaller radius of curvature r3 is more suitable than one with a longer length l. 挠曲 The flexural member 1216 is optimally matched, while the curved second connecting portion 1228 with a larger radius of curvature r3 is matched with a shorter length l. 挠曲 The flexural member 1216 is optimally matched. Besides the length l of the flexural member 1216... 挠曲 In addition, the ability of the flexural member 1216 to apply torque on the spokes 1200 is also affected by the stiffness of the material used to manufacture the flexural member 1216. Therefore, when using a softer material, it is desirable to provide a longer length l. 挠曲 The flexural member 1216, and when using a stiffer material, it is desirable to provide a shorter length l. 挠曲 Flexural member 1216.

[0074] The non-pneumatic tires described herein improve the robustness of the non-pneumatic tire by providing an arrangement in which adjacent spokes contact one another during a high impact event. The contact between adjacent spokes causes multiple spokes to share the load, thereby significantly reducing the stress experienced by any single spoke in the non-pneumatic tire. As a result, the durability of the non-pneumatic tire is improved.

[0075] In the above-described embodiment, the foot 214 of the spoke 200 is initially substantially straight and is joined to the curved outer surface 24 of the lower ring 20. This joining process forces the foot 214 to conform to the curvature of the outer surface 24. While this arrangement results in a relatively simple manufacturing process for the spoke 200 and the lower ring 20, it can create other potential design difficulties. For example, in the flat foot embodiment, the primary applied force acting on the joint between the spoke and the ring is tension. This tension can result in a cracking-type failure at the leading edge of the spoke. As another example, the rotational position of each spoke relative to the lower and upper rings cannot be adjusted without undesirably introducing a pre-stress into the spoke.

[0076] Rotational adjustment of the spokes can be necessary in view of manufacturing tolerances. Ideally, each spoke of a non-pneumatic tire would be identical, including the dimensions of the individual elements (e.g., the lengths of the foot, the first connecting portion, and the second connecting portion) and the angles between these elements (e.g., the angle between the foot 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 each spoke will be identical. Manufacturing guidelines recognize variations within the formed characteristics of a product, such as material thickness and tempering tolerances. Additionally, these manufacturing guidelines recognize variations within the bending angle tolerance, one guideline suggesting a + / - one degree tolerance.

[0077] Figure 13 And Figure 14 This + / - one degree tolerance is shown how it can affect the support structure of a non-pneumatic tire. According to the non-pneumatic tire embodiment of Figures 1 to 6 Figure 13 And Figure 14 the non-pneumatic tire. Accordingly, like features will be denoted by like reference numerals.

[0078] Figure 13 And Figure 14 The first spoke 200a, the second spoke 200b, and the third spoke 200c are shown. In the first spoke 200a and the third spoke 200c, the angle Θ between the foot 214 and the first connecting portion 226 is one degree less than the prescribed design value, while in the second spoke 200b, the angle Θ is one degree greater than the design value. Figure 13 ​The spoke 200 is shown when the foot 214 is connected to the lower ring 20 and the second end 208 of each spoke 200 is in a natural or at-rest position (i.e., the position of the second end 208 of the spoke 200 without any external forces applied and before the flexure member 216 is attached to the upper ring 30). Figure 14 The spoke 200 is shown after the second end 208 of the spoke 20 has been moved to the desired position and the flexure member 216 is attached to the upper ring 30. As Figure 13 shown, having the angle between the foot 214 and the first connection portion 226 off by one degree of specification can cause various problems, including having the flexure member 216 naturally rest above the upper ring 30 (second spoke 200b) or below the upper ring 30 (first 200a and third spoke 200c), and having irregular spacing between adjacent spokes 200. Some of these problems can be corrected by forcing the second end 208 of each spoke 200 into the desired position, as Figure 14 shown, but doing so undesirably introduces a pre-stress into the spoke 200. In theory, 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 214 and the outer surface of the lower ring 20.

[0079] Figure 15 An alternative embodiment of a portion of a non-pneumatic tire is shown having features that mitigate the above-described problems with manufacturing tolerances. Figure 16 A single spoke of a non-pneumatic tire is shown. Figure 15 The arrangement shown in Figure 15 and Figure 16 is substantially similar to the arrangement shown in Figures 1 to 6 with the differences described herein. Accordingly, like features will be identified by the same numerals increased by the value “2000”.

[0080] The non-pneumatic tire 2010 includes a support structure 2100 connecting the lower ring 2020 to an upper ring (not shown). The support structure 2100 is composed of a plurality of spokes 2200 arranged into a first spoke set and a second spoke set (not shown). The first spoke set and the second spoke set are offset from and spaced apart from each other in an axial direction of the non-pneumatic tire 2010.

[0081] Reference is made to Figure 16Each 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 foot 2214 is disposed toward the first end 2206 of the spoke 2200. A flex member 2216 is disposed at the second end 2208 of the spoke 2200. A knuckle portion 2222 is disposed between the first end 2206 and the second end 2208. A transition portion 2224 is disposed between the knuckle portion 2222 and the first end 2206. The foot 2214 extends from the transition portion 2224 toward the first end 2206 of the spoke 2200. A first connecting portion 2226 connects the transition portion 2224 to the knuckle portion 2222, and a second connecting portion 2228 connects the knuckle portion 2222 to the second end 2208 of the spoke 2200.

[0082] The outer surface 2024 of the lower ring 2020 is provided with a plurality of scallop notches 2025 equal in number to the total number of spokes 2200 in the support structure (only a single scallop notch is shown in Figure 15 Fig. 2). The first surface 2210 of the spoke 2200 at the foot 2214 is curved and has a radius of curvature r s that is equal to the radius of curvature r fp of the corresponding scallop notch 2025. The scallop notches 2025 are spaced apart from each other in the circumferential direction of the non-pneumatic tire 2010, and are arranged into first and second groups of scallop notches (not shown). Similar to the spacing between the first and second groups of spokes, the groups of scallop notches are also offset and spaced apart from each other in the axial direction of the non-pneumatic tire 2010. The curved first surface 2210 of the spoke 2200 at the foot 2214 is joined to the corresponding scallop notch 2025 to attach the first end of the spoke 2200 to the lower ring 2020. The flex member 2216 is joined to the upper ring to connect the second end 2208 of the spoke 2200 to the upper ring 2030. In alternative embodiments, the foot or the flex member can be attached to the scallop notch or the upper ring, respectively, with any desired arrangement. For example, the curved first surface of the spoke at the foot can be attached to the corresponding scallop notch with a nut and bolt arrangement, where the bolt extends into a through hole provided on the spoke and the lower ring, exposing a threaded portion that receives the nut. Such a nut and bolt attachment can also be used to attach the flex member to the upper ring. In other alternative embodiments, instead of separate groups of scallop notches, each scallop notch can extend continuously across the lower ring in the axial direction, and the spokes of the first and second groups of spokes can share the corresponding scallop notch.

[0083] The above arrangement helps address the potential design issue associated with the flat footed spoke implementation regarding spoke manufacturing tolerances. Providing the spoke 2200 with a curved foot 2214 and a corresponding curved scalloped notch 2205 on the lower ring 2020 for the non-pneumatic tire 2010 makes the primary applied force on the joint between the spoke 2200 and the lower ring 2020 a shear force, rather than a tension force as in the flat footed implementation. This change reduces the likelihood of a crack-type failure mode occurring at the joint between the spoke 2200 and the lower ring 2020. In addition, the shear force on the joint between the spoke 2200 and the lower ring 2020 puts the joint into a significantly stronger failure mode for the most commonly used adhesives.

[0084] In addition, the curved surfaces of the spoke 2200 and the scalloped notch 2025 allow for adjustment of the rotational position of each spoke 2200 relative to the lower ring 2020 and the upper ring 2030 without pre-introducing stresses into the spoke as is the case with the flat footed implementation. The curved surfaces of the spoke 2200 and the scalloped notch 2025 also allow for a constant adhesive gap to be maintained during such rotational position adjustment.

[0085] It has been found that the radius of curvature r fp at the foot 2214 of the spoke 2200 and the radius of curvature r s of the scalloped notch 2025 should conform to certain design principles in order to provide the above flexibility with respect to rotational position adjustment. According to one exemplary design principle, the radius of curvature r fp at the foot 2214 of the spoke 2200 is different than the radius of curvature r s of the scalloped notch 2025. lr .

[0086] In the illustrated implementation, both the curved second surface 2212 of the spoke 2200 at the foot 2214 and the scalloped notch 2025 are convex relative to the inner surface 2023 of the lower ring 2020, and the radius of curvature r fp at the foot 2214 of the spoke 2200 and the radius of curvature r s of the scalloped notch 2025 are constant and equal to each other. In addition, the scalloped notch 2025 is formed directly on the lower ring 2020. In alternative implementations, the second surface of the spoke can be convex relative to the inner surface of the spoke, and the lower ring can be provided with a corresponding bump that is also convex relative to the inner surface of the spoke. In other alternative implementations, the radius of curvature at the foot or the radius of curvature of the scalloped notch or bump can be variable or different from each other. In further alternative implementations, the scalloped notch or bump can be formed on a sleeve that is fixed to the outer surface of the lower ring.

[0087] Figures 17 to 19 Another implementation of a non-pneumatic tire 3010 is shown. Figures 17 to 19The non-pneumatic tire 3010 is substantially the same as the non-pneumatic tire 2010 of Figures 15 to 16 the non-pneumatic tire 2010, except for the differences described herein. Accordingly, like features will be identified by like numerals increased by a factor of “1000.”

[0088] The non-pneumatic tire 3010 includes a support structure 3100 connecting the lower ring 3020 to the upper ring 3030. The support structure 3100 is composed of a plurality of spokes 3200 arranged into a first spoke set and a second spoke set (not shown). In the illustrated embodiment, only a single row of spokes 3200 is shown for clarity, and the spokes 3200 extend the entire axial width of the lower ring 3020. However, when two spoke sets are used, the lower ring 3020 can have an axial width that is at least twice the width of a single spoke.

[0089] Each spoke 3200 extends between a first end 3206 and a second end 3208. A foot 3214 is disposed toward the first end 3206 of the spoke 3200. A flex member 3216 is disposed at the second end 3208 of the spoke 3200.

[0090] The lower ring 3020 is provided with a plurality of scalloped notches 3024 equal in number to the total number of spokes 3200 in the support structure 3100. The scalloped notches 3024 are spaced apart from one another along the circumferential direction of the non-pneumatic tire 3010, and are arranged into a first scalloped notch set and a second scalloped notch set (not shown). Similar to the spacing between the first spoke set and the second spoke set, the scalloped notch sets are also offset and spaced apart from one another in the axial direction of the non-pneumatic tire 3010. In alternative embodiments, each scalloped notch can extend continuously along the axial direction across the lower ring, and the spokes of the first spoke set and the second spoke set can share a respective scalloped notch.

[0091] Mechanical fastening devices 3080 connect the feet 3214 of the spokes 3200 to respective scalloped notches 3205 to attach the first ends 3206 of the spokes 3200 to the lower ring 3020. Adhesive (not shown) can reinforce the connection by bonding the components together. The adhesive can prevent wear between the individual components due to cyclic loading, and can also prevent deterioration due to exposure to environmental factors (e.g., corrosion). The flex members 3216 are attached to the upper ring 3030 to connect the second ends 3208 of the spokes 3200 to the upper ring 3030.

[0092] In the illustrated embodiment, the mechanical fastening devices 3080 include a cleat 3082 and two hex-head screws 3084. The cleat 3082 includes substantially the same axial width as the foot 3214, and a face 3086 having a radius of curvature substantially the same as the radius of curvature of the foot 3214. In alternative embodiments, the axial width of the cleat can be greater or less than the axial width of the foot. In other alternative embodiments, the radius of curvature of the face of the cleat can differ from the radius of curvature of the foot.

[0093] Each mechanical fastening device 3080 is configured such that the head of the hex-head screw 3084 is positioned radially inward of the lower ring 3020, and the threaded portion of the hex-head screw 3084 extends through the lower ring 3020, the foot 3214, and the cleat 3082. The foot 3214 is provided with a through-hole (not shown) to allow passage of the hex-head screw 3084. The through-hole can be oversized or provided as a slot to allow adjustment of the position of the spoke 3200 relative to the lower ring 3020.

[0094] The threaded portion of the hex-head screw 3084 engages an internal thread provided on the cleat 3082, and the cleat 3082 is positioned with the foot 3214 radially outward. In alternative embodiments, the orientation of the fastening device can be reversed, such that the head of the hex-head screw is positioned radially outward of the cleat, and the threaded portion engages an internal thread provided on the lower ring. In other alternative embodiments, the hex-head screws can be provided at any desired location, can be any desired size, and there can be more or fewer screws. In yet another alternative embodiment, the mechanical fastening devices, lower ring, and / or foot can be sized and configured such that the second fastener does not extend through the lower ring or cleat. In further alternative embodiments, any desired mechanical fastening device can be used (e.g., studs or set screws in combination with a nut and washer, rivets).

[0095] The mechanical fastening devices 3080 distribute load across the axial width of the foot 3214 of the spoke 3200, providing a more robust structure and also can provide a more rigid connection. In addition, the use of the cleat 3082 can facilitate construction of the non-pneumatic tire 3010 by eliminating the need for a clamping device when only adhesive is used. Further, the mechanical fastening devices 3080 allow for individual removal, maintenance, and installation of a single spoke.

[0096] Figure 20 and Figure 21 Another embodiment of a non-pneumatic tire 4010 is shown. Figure 20 and Figure 21 The non-pneumatic tire 4010 of Figures 17 to 19 is substantially the same as the non-pneumatic tire 3010 of , except for the differences described herein. Accordingly, like features will be identified by like numerals increased by a factor of “1000.”

[0097] The non-pneumatic tire 4010 includes a support structure 4100 connecting the lower ring 4020 to the upper ring 4030. The support structure 4100 is composed of a plurality of spokes 4200 arranged into first and second groups of spokes (not shown).

[0098] Each spoke 4200 extends between a first end 4206 and a second end 4208. A foot 4214 is disposed toward the first end 4206 of the spoke 4200. A flex member 4216 is disposed at the second end 4208 of the spoke 4200. An elbow portion 4222 is disposed between the first end 4206 and the second end 4208. A transition portion 4224 is disposed between the elbow portion 4222 and the first end 4206. The foot 4214 extends from the transition portion 4224 toward the first end 4206 of the spoke 4200. A first connecting portion 4226 connects the transition portion 4224 to the elbow portion 4222, and a second connecting portion 4228 connects the elbow portion 4222 to the second end 4208 of the spoke 4200.

[0099] The lower ring 4020 is provided with a plurality of scalloped notches 4024 equal in number to the total number of spokes 4200 in the support structure 4100. The scalloped notches 4024 are spaced apart from one another along a circumferential direction of the non-pneumatic tire 4010, and are arranged into first and second groups of scalloped notches (not shown). Similar to the spacing between the first and second groups of spokes, the groups of scalloped notches are also offset and spaced apart from one another in an axial direction of the non-pneumatic tire 4410. In alternative embodiments, each scalloped notch can extend continuously across the lower ring in the axial direction, and spokes of the first and second groups of spokes can share a respective scalloped notch.

[0100] Mechanical fastening devices 4080 connect the feet 4214 of the spokes 4200 to respective scalloped notches 4205 to attach the first ends 4206 of the spokes 4200 to the lower ring 4020. The mechanical fastening devices 4080 are substantially identical to the mechanical fastening devices 3080 shown in Figures 17 to 19 and are not further described. An adhesive (not shown) can be used to reinforce the connection by bonding the components together. The adhesive can prevent wear between the individual components due to cyclic loading, and can also prevent deterioration due to exposure to environmental factors (e.g., corrosion). The flex members 4216 are attached to the upper ring 4030 to connect the second ends 4208 of the spokes 4200 to the upper ring 4030.

[0101] As described above, in embodiments of the non-pneumatic tire 4010, Figures 1 to 19 the elbow portion and the transition portion are concavely curved in opposite facing directions relative to the individual spokes. In contrast, according to the non-pneumatic tire 4410, Figure 20 and Figure 21In embodiments, the knuckle portion 4222 and the transition portion 4224 are concavely curved in the same direction. This arrangement can provide benefits with respect to how the mechanical fastening devices 4080 and the adhesive (if used) are loaded and bear stress. In particular, arranging the knuckle portion 4222 and the transition portion 4224 to be concavely curved in the same direction can create a compression effect between the spoke 4200 and the lower ring 4020, which can reduce peeling issues and better distribute stress, providing a more robust structure.

[0102] While specific embodiments and variations have been shown and described in Figures 1 to 21 , the disclosed features are not exclusive to each described embodiment. Rather, various features can be combined between embodiments as desired. For example, the arrangement of the spoke curved foot shown and described in Figure 15 and Figure 16 may be combined with the curved connecting portion of the spoke shown and described in Figure 12 and Figure 12a .

[0103] To the extent the term “includes” or “including” is used in the specification or the claims, it is intended to be inclusive in a manner similar to “comprising” as an open transition term without precluding the presence of elements other than the recited elements. Additionally, to the extent the term “or” is used in the specification or the claims, it is intended to mean “either” in the absence of more specific language such as “only one of” or “exactly one of.” When the applicant intends to indicate “only one of” or “exactly one of,” the term “only one of” or “exactly one of” will be specifically recited. Thus, use of the term “or” herein is the inclusive, and not the exclusive use. See, Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d Ed. 1995). Additionally, to the extent the term “in” is used in the specification or the claims, it is intended to further mean “on” as well as “in” such that for example, a component can be connected “in” or “on” one side of another component. Further, to the extent the term “connected” is used in the specification or the claims, it is intended to be inclusive of both direct connection and indirect connection, such as through one or more additional components.

[0104] While the application has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention that the application be limited thereto. Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the application in its broader aspects is not limited to the specific details, representative apparatus, and methods, and illustrative examples. For example, each spoke can be provided with a rubber coating to cushion impact when contact occurs between adjacent spokes. Consequently, departures can be made from such details without departing from the spirit or scope of applicant's general inventive concept.

Claims

1. A non-pneumatic tire, the non-pneumatic tire comprising: a lower ring provided with a plurality of scallop notches, each of the plurality of scallop notches having a first curved surface; an upper ring substantially coaxial with the lower ring; and a support structure connecting the lower ring to the upper ring, the support structure comprised of a plurality of spokes arranged in a first set of spokes and a second set of spokes axially spaced apart from the first set of spokes, each of the plurality of spokes comprising: a first end connected to the lower ring; a second end connected to the upper ring; a first surface and a second surface facing oppositely to the first surface, each of the first surface and the second surface extending between the first end and the second end; and a foot portion disposed toward the first end of the spoke, the first surface of the spoke at the foot portion being a second curved surface that is attached to the first curved surface of one of the plurality of scallop notches to connect the first end of the spoke to the lower ring, wherein the first curved surface of each of the plurality of scallop notches and the second curved surface of the foot portion of each of the plurality of spokes are configured to allow adjustment of a rotational position of each of the plurality of spokes relative to the lower ring and the upper ring without inducing a pre-stress in each of the plurality of spokes, and wherein the second surface of the spoke at the foot portion is concave relative to the upper ring and is positioned to face the upper ring.

2. The non-pneumatic tire of claim 1, wherein each of the first curved surface and the second curved surface is convex relative to an inner surface of the lower ring.

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

4. The non-pneumatic tire of claim 1, wherein the first curved surface has a first radius of curvature and the second curved surface has a second radius of curvature, and wherein the first radius of curvature is equal to the second radius of curvature.

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

6. The non-pneumatic tire of claim 1, wherein the spokes of the first set of spokes are concavely curved relative to a first circumferential direction of the tire, and the spokes of the second set of spokes are convexly curved relative to the first circumferential direction of the tire.

7. The non-pneumatic tire of claim 1, wherein each of the plurality of spokes comprises: an elbow portion located between the first end and the second end; and a transition portion located between the first end and the elbow portion; ​ wherein the elbow portion and the transition portion are concavely curved in opposite facing directions.

8. The non-pneumatic tire of claim 1, wherein each of the plurality of spokes comprises: an elbow portion located between the first end and the second end; and a transition portion located between the first end and the elbow portion; wherein the elbow portion and the transition portion are concavely curved in the same direction.

9. The non-pneumatic tire of claim 1, wherein each of the plurality of spokes further comprises a flexure member attached to the spoke and the upper ring to connect the second end of the spoke to the upper ring.

10. The non-pneumatic tire of claim 1, wherein the non-pneumatic tire is arranged and configured such that adjacent ones of the plurality of spokes do not contact each other when the non-pneumatic tire is in a first state, and such that adjacent ones of the plurality of spokes contact each other when the non-pneumatic tire is in a second state, the first state being when the tire is rolling on a flat surface, the second state being when the tire is rolling on an uneven surface.

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 scalloped notches on the lower ring, each of the plurality of scalloped notches having a first curved surface; forming a plurality of spokes, each spoke having a first surface and a second surface facing opposite the first surface, the first and second surfaces each extending between a first end and a second end, the step of forming a plurality of spokes comprising providing a foot portion toward the first end of the spoke, the first surface of the spoke at the foot portion being a second curved surface, the second surface of the spoke at the foot portion being concave with respect to the upper ring and positioned to face the upper ring; connecting the lower ring to the upper ring with the plurality of spokes, the step of connecting the lower ring to the upper ring comprising attaching the second curved surface of the spoke at the foot portion to the first curved surface of one of the plurality of scalloped notches to connect the first end of the spoke to the lower ring and the second end of the spoke to the upper ring, wherein the first curved surface of each of the plurality of scalloped notches and the second curved surface of the foot portion of each of the plurality of spokes are configured to allow adjustment of a rotational position of each of the plurality of spokes relative to the lower ring and the upper ring without inducing a pre-stress in each of the plurality of spokes.

12. The method of manufacturing a non-pneumatic tire of claim 11, wherein forming a plurality of scalloped notches comprises providing the first curved surface as a first convex surface relative to an inner surface of the lower ring, and wherein forming a plurality of spokes comprises providing the first surface of the spoke at the foot portion as a second convex surface relative to the inner surface of the lower ring.

13. The method of manufacturing a non-pneumatic tire of claim 11, wherein forming a plurality of scallop notches comprises providing a first radius of curvature to the first curved surface, and wherein forming a plurality of spokes comprises providing a second radius of curvature to the first surface of the spokes at the foot, wherein the first radius of curvature and the second radius of curvature are different than a third radius of curvature of an outer surface of the lower ring.

14. The method of manufacturing a non-pneumatic tire of claim 11, further comprising the steps of: attaching a flex member to each spoke, and attaching the flex member to the upper ring, wherein attaching the flex member to the upper ring connects the second end of the spoke to the upper ring during connecting the lower ring to the upper ring.

15. The method of manufacturing a non-pneumatic tire of claim 11, further comprising the steps of: attaching a flex member to each spoke, and attaching the flex member to the upper ring, wherein attaching the flex member to the upper ring connects the second end of the spoke to the upper ring during connecting the lower ring to the upper ring.

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