Non-pneumatic tires

Abstract

To provide a non-pneumatic tire that can enhance uniformity of rigidity in a tire circumferential direction while reducing pitch noise.SOLUTION: A non-pneumatic tire 1 comprises: an inner annular part 20; an outer annular part 30 arranged on an outer periphery side of the inner annular part 20, concentrically with the inner annular part 20; a plurality of spokes 40 arranged along a tire circumferential direction to connect the inner annular part 20 to the outer annular part 30; and a tread 50 provided on an outer peripheral surface of the outer annular part 30. The tread 50 has a tread pattern in which a plurality of pitch elements with different pitch lengths P1 are arranged along the tire circumferential direction in a first arrangement pattern, and the plurality of spokes 40 are arranged along the tire circumferential direction at pitches corresponding to pitches of the first arrangement pattern.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a non-pneumatic tire.

Background Art

[0002] In recent years, non-pneumatic tires that do not cause problems such as punctures and do not require air pressure adjustment have been developed. Generally, a non-pneumatic tire has a structure in which an inner peripheral side annular portion and an outer peripheral side annular portion arranged coaxially are connected by a plurality of spokes. The plurality of spokes are arranged radially at intervals in the tire circumferential direction. A tread that contacts the road surface is provided on the outer peripheral surface of the outer annular portion.

[0003] For example, Patent Document 1 discloses a non-pneumatic tire in which a reinforcing portion is provided on a spoke and the riding comfort can be improved by appropriately setting the area of the reinforcing portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] This type of non-pneumatic tire generates pitch noise during driving. This pitch noise occurs when the spokes strike the road surface. According to the configuration of Patent Document 1 above, although the riding comfort can be improved, the pitch noise during driving is not considered. Also, the appropriate relationship between the tread pattern and the spokes in consideration of the rigidity of the tire has not been studied.

[0006] An object of the present invention is to provide a non-pneumatic tire capable of reducing pitch noise and enhancing the uniformity of the rigidity of the tire.

Means for Solving the Problems

[0007] The non-pneumatic tire of the present invention comprises an inner annular portion, an outer annular portion arranged coaxially with the inner annular portion on the outer circumference of the inner annular portion, a plurality of spokes connecting the inner annular portion and the outer annular portion and arranged along the tire circumferential direction, and a tread provided on the outer circumferential surface of the outer annular portion, wherein the tread has a tread pattern in which a plurality of pitch elements with different pitch lengths are arranged in a first arrangement pattern along the tire circumferential direction, and the plurality of spokes are arranged along the tire circumferential direction at a pitch corresponding to the first arrangement pattern. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a non-pneumatic tire that can reduce pitch noise while improving the uniformity of tire rigidity. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view showing the non-pneumatic tire of this embodiment. [Figure 2] This is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] Figure 2 is a perspective view of a portion of a non-pneumatic tire, seen from an oblique angle. [Figure 4] This is a schematic diagram showing the division of pitch elements in a tread pattern. [Figure 5] Figure 1 is an enlarged view of section V, which is a partial side view of a non-pneumatic tire. [Figure 6] This is a view of the spoke connection points as seen through the unfolded diagram of Figure 4. [Figure 7] This figure corresponds to Figure 6 and shows modified examples of the first and second sequence patterns. [Modes for carrying out the invention]

[0010] This embodiment will be described below with reference to the drawings. Figure 1 is a side view of the non-pneumatic tire 1 of this embodiment, viewed from a direction parallel to the tire rotation axis (tire meridian), that is, along the front-to-back direction of the paper in Figure 1. The non-pneumatic tire 1 shown in Figure 1 is in an unloaded state. Figure 2 is a cross-sectional view taken along line II-II of Figure 1. Figure 3 is a partial perspective view of the non-pneumatic tire 1, taken from an oblique angle from the portion shown in Figure 2.

[0011] In Figures 1 and 3, arrow C indicates the circumferential direction of the tire. In Figures 1 through 3, arrow X indicates the radial direction of the tire. In Figures 2 and 3, arrow Y indicates the width direction of the tire. In Figure 1, the tire width direction Y is the front-to-back direction of the paper. In Figure 2, the symbol E is the tire equatorial plane. In Figure 2, the tire circumferential direction C is the front-to-back direction of the paper.

[0012] The tire circumferential direction C is the direction around the tire rotation axis and is the same direction in which the non-pneumatic tire 1 rotates. The tire radial direction X is the direction perpendicular to the tire rotation axis. The tire width direction Y is the direction parallel to the tire rotation axis. In Figures 2 and 3, one side of the tire width direction Y is shown as Y1 and the other side of the tire width direction Y is shown as Y2. The tire equatorial plane E shown in Figure 2 is a plane perpendicular to the tire rotation axis and located at the center of the tire width direction Y. The same applies to the directions indicated by these symbols in Figures 4 to 7.

[0013] The non-pneumatic tire 1 of this embodiment comprises an inner annular portion 20, an outer annular portion 30, a plurality of spokes 40, and a tread 50. In the following, the thickness of the inner annular portion 20 and the outer annular portion 30 refers to the dimension in the direction along the tire radial direction X. The width of the inner annular portion 20 and the outer annular portion 30 refers to the dimension in the direction along the tire width direction Y as shown in Figure 2.

[0014] The inner annular portion 20 is an annular portion along the tire circumferential direction C that constitutes the inner peripheral portion of the non-pneumatic tire 1. The thickness and width of the inner annular portion 20 are set to be constant in order to improve uniformity. A tire wheel (not shown) is disposed in the space on the inner peripheral side of the inner annular portion 20. The inner peripheral portion of the inner annular portion 20 is fitted and mounted on the outer peripheral portion of the rim of the tire wheel. When the inner annular portion 20 is mounted on the rim, the non-pneumatic tire 1 is mounted on the tire wheel. A fitting portion composed of convex portions, grooves, etc. may be provided on the inner peripheral surface of the inner annular portion 20 for fitting with the rim. The inner annular portion 20 can be formed of, for example, a resin material having elasticity, but the material is not limited to resin.

[0015] The inner annular portion 20 transmits the rotation of the tire wheel to the spokes 40 and the outer annular portion 30. The thickness of the inner annular portion 20 is determined from the viewpoint of achieving weight reduction and durability while satisfying the function of sufficiently transmitting the rotational force to the spokes 40. The thickness of the inner annular portion 20 is not particularly limited, but for example, it is preferably 2% or more and 7% or less of the tire cross-sectional height H shown in FIG. 2, and more preferably 3% or more and 6% or less.

[0016] The inner diameter of the inner annular portion 20 is determined according to the dimensions of the rim of the tire wheel on which the non-pneumatic tire 1 is mounted, the use of the vehicle, etc. For example, when assuming replacement of a general pneumatic tire, the inner diameter of the inner annular portion 20 may be, for example, dimensions such as 250 mm or more and 500 mm or less, but is not limited thereto.

[0017] The width of the inner annular portion 20 is appropriately determined according to the use of the vehicle on which the non-pneumatic tire 1 is mounted, etc. For example, when assuming replacement of a general pneumatic tire, the width of the inner annular portion 20 may be dimensions such as 100 mm or more and 300 mm or less, but is not limited thereto.

[0018] The outer annular portion 30 is an annular portion along the tire circumferential direction C that constitutes the outer peripheral portion of the non-pneumatic tire 1. The outer annular portion 30 is arranged coaxially with the inner annular portion 20 on the outer peripheral side of the inner annular portion 20. The thickness and width of the outer annular portion 30 are set to be constant in order to improve uniformity. The outer annular portion 30 can be formed of, for example, a resin material having elasticity, but the material is not limited to resin.

[0019] The outer annular portion 30 transmits the rotation of the inner annular portion 20 and the spokes 40 to the road surface via the tread 50. The thickness of the outer annular portion 30 is determined from the viewpoint of achieving weight reduction and durability while satisfying the function of sufficiently transmitting the rotational force from the spokes 40 to the road surface. The thickness of the outer annular portion 30 is not particularly limited, but for example, it is preferably 2% or more and 7% or less of the tire cross-sectional height H shown in FIG. 2, and more preferably 2% or more and 5% or less.

[0020] The inner diameter of the outer annular portion 30 is appropriately determined according to the dimensions of the rim of the tire wheel to which the non-pneumatic tire 1 is mounted, the use of the vehicle, and the like. For example, when assuming replacement of a general pneumatic tire, the inner diameter of the outer annular portion 30 may be dimensions such as 420 mm or more and 750 mm or less, but is not limited thereto.

[0021] The width of the outer annular portion 30 is appropriately determined according to the use of the vehicle to which the non-pneumatic tire 1 is mounted, and the like. For example, when assuming replacement of a general pneumatic tire, the width of the outer annular portion 30 may be dimensions such as 100 mm or more and 300 mm or less, but is not limited thereto.

[0022] The plurality of spokes 40 connect the inner annular portion 20 and the outer annular portion 30. The inner annular portion 20 and the outer annular portion 30 connected by the plurality of spokes 40 are arranged coaxially with each other. Each of the plurality of spokes 40 is independently arranged along the tire circumferential direction C. As shown in FIG. 1, when the non-pneumatic tire 1 is in an unloaded state, the plurality of spokes 40 extend linearly in the radial direction substantially parallel to the tire radial direction X in a side view.

[0023] As shown in Figures 2 and 3, the spokes 40 of this embodiment include a plurality of first spokes 41 and a plurality of second spokes 42. The extending direction of both the first spokes 41 and the second spokes 42 is not parallel to the tire radial direction X when viewed along the tire circumferential direction C. The first spokes 41 are inclined toward one side in the tire axial direction, i.e., the tire width direction Y. The second spokes 42 are inclined toward the opposite side from the first spokes 41. The first spokes 41 and the second spokes 42 are arranged alternately in the tire circumferential direction C.

[0024] More specifically, as shown in Figures 2 and 3, the first spoke 41 extends inclined from the Y1 side, which is one side of the outer annular portion 30 in the tire width direction Y, toward the Y2 side, which is the other side of the inner annular portion 20 in the tire width direction Y. The second spoke 42 extends inclined from the Y2 side, which is the other side of the outer annular portion 30 in the tire width direction Y, toward the Y1 side, which is one side of the inner annular portion 20 in the tire width direction Y.

[0025] The inclination angles of the first spoke 41 and the second spoke 42 are the same. Therefore, when viewed from a direction along the tire circumferential direction C, the first spoke 41 and the second spoke 42 adjacent to each other in the tire circumferential direction C are arranged in a roughly X shape. As shown in Figure 2, the first spoke 41 and the second spoke 42 are inclined at an angle θ with respect to the tire width direction Y, and this angle θ is preferably, for example, 30° to 60°.

[0026] As shown in Figure 2, when viewed from a direction along the tire circumferential direction C, the first spoke 41 and the second spoke 42 each have the same shape, symmetrical with respect to the tire equatorial plane E. Therefore, in the following, there is no need to distinguish between the first spoke 41 and the second spoke 42, and when they can be described together, the first spoke 41 and the second spoke 42 will be collectively referred to as spoke 40.

[0027] The spokes 40 are plate-shaped and extend diagonally from the inner annular portion 20 toward the outer annular portion 30 at an angle θ as described above. As shown in Figure 3, the plate thickness t of the spokes 40 along the tire circumferential direction is smaller than the plate width w, and the direction of the plate thickness t is along the tire circumferential direction C. That is, the spokes 40 are formed in a plate shape that extends along the plane of the tire radial direction X and the tire width direction Y. The plate width w referred to here is the dimension in the direction perpendicular to the inclination direction on which the spokes 40 extend, when the spokes 40 are viewed from the direction along the tire circumferential direction C, as also shown in Figure 2. In this embodiment, the plate thickness t of all spokes 40 is the same. Also, the plate width w of all spokes 40 is the same.

[0028] Since the spokes 40 are long, plate-shaped, even if the plate thickness t is reduced, the durability of the spokes 40 can be improved by setting a wider plate width w. Furthermore, by reducing the plate thickness t and increasing the number of spokes 40, the spacing between adjacent spokes 40 in the tire circumferential direction C can be reduced while maintaining the overall rigidity of the non-pneumatic tire 1. This distributes the contact pressure during tire rolling by the spokes 40, thereby reducing the contact pressure. In this embodiment, the spokes 40 are parallel to the tire radial direction X in a side view, but the spokes 40 may also be arranged diagonally to the tire radial direction X so as to intersect with the tire radial direction X in a side view.

[0029] As shown in Figures 2 and 3, the first spoke 41 has a first inner connecting portion 411 that connects to the inner annular portion 20 on the tire width direction Y2 side, and a first outer connecting portion 412 that connects to the outer annular portion 30 on the tire width direction Y1 side. The second spoke 42 has a second inner connecting portion 421 that connects to the inner annular portion 20 on the tire width direction Y1 side, and a second outer connecting portion 422 that connects to the outer annular portion 30 on the tire width direction Y2 side. The first outer connecting portion 412 and the second outer connecting portion 422 are examples of connecting portions of the spoke 40 connected to the outer annular portion 30 in this embodiment.

[0030] As shown in Figure 2, the first inner connecting portion 411 of the first spoke 41 has a shape that widens along the tire width direction Y as it approaches the inner annular portion 20. The side surface 411a of the first inner connecting portion 411 on the tire width direction Y2 side extends in a gentle curve to the end 20b of the inner annular portion 20 on the tire width direction Y2 side. The side surface 411b of the first inner connecting portion 411 on the tire width direction Y1 side extends in a curve toward the tire width direction Y1 to the position of the tire equatorial plane E of the inner annular portion 20.

[0031] The first outer connecting portion 412 of the first spoke 41 has the same shape as the first inner connecting portion 411, and has a shape that widens along the tire width direction as it approaches the outer annular portion 30. The side surface 412a of the first outer connecting portion 412 on the tire width direction Y1 side extends in a gentle curve to the end 30a of the outer annular portion 30 on the tire width direction Y1 side. The side surface 412b of the first outer connecting portion 412 on the tire width direction Y2 side extends in a curve toward the tire width direction Y2 to the position of the tire equatorial plane E of the outer annular portion 30. The first inner connecting portion 411 is provided in half of the inner annular portion 20 on the tire width direction Y2 side. The first outer connecting portion 412 is provided in half of the outer annular portion 30 on the tire width direction Y1 side.

[0032] As shown in Figure 2, the second inner connecting portion 421 of the second spoke 42 has a shape that widens along the tire width direction Y as it approaches the inner annular portion 20. The side surface 421a of the second inner connecting portion 421 on the tire width direction Y1 side extends in a gentle curve to the end 20a of the inner annular portion 20 on the tire width direction Y1 side. The side surface 421b of the second inner connecting portion 421 on the tire width direction Y2 side extends in a curve toward the tire width direction Y2 to the position of the tire equatorial plane E of the inner annular portion 20.

[0033] The second outer connecting portion 422 of the second spoke 42 has the same shape as the second inner connecting portion 421, and has a shape that widens along the tire width direction as it approaches the outer annular portion 30. The side surface 422a of the second outer connecting portion 422 on the tire width direction Y2 side extends in a gentle curve to the end 30b of the outer annular portion 30 on the tire width direction Y2 side. The side surface 422b of the second outer connecting portion 422 on the tire width direction Y1 side extends in a curve toward the tire width direction Y1 to the position of the tire equatorial plane E of the outer annular portion 30. The second inner connecting portion 421 is provided in half of the inner annular portion 20 on the tire width direction Y1 side. The second outer connecting portion 422 is provided in half of the outer annular portion 30 on the tire width direction Y2 side.

[0034] As described above, the plate thickness t of all spokes 40 in this embodiment is the same. The dimension of the plate thickness t is not particularly limited, but in order for the spokes 40 to receive sufficient rotational force from the inner annular portion 20 and the outer annular portion 30, and to be able to deform appropriately when subjected to a load, it is preferably 1 mm to 30 mm, and more preferably 5 mm to 25 mm.

[0035] As described above, the plate width w of all spokes 40 in this embodiment is the same. The plate width w of the spokes 40 is not particularly limited, but it is preferably 5 mm to 25 mm, and more preferably 10 mm to 20 mm, in order to sufficiently receive the rotational force from the inner annular portion 20 and the outer annular portion 30, while also allowing for appropriate deflection and deformation when a load is applied. Furthermore, the plate width w is preferably 110% or more of the plate thickness t, and more preferably 115% or more, from the viewpoint of improving durability and distributing the ground pressure.

[0036] The number of spokes 40 is preferably 80 to 300, and more preferably 100 to 200, from the viewpoint of being able to adequately support the load from the vehicle, reduce weight, and improve both power transmission and durability.

[0037] The spokes 40 can be formed from the elastic materials listed below. First, regarding the properties of the elastic material, from the viewpoint of providing appropriate rigidity while ensuring sufficient durability, it is preferable that the tensile modulus calculated from the tensile stress at 10% elongation, as determined by a tensile test conducted in accordance with JIS K7312:1996, is between 3 MPa and 12 MPa.

[0038] If the tensile modulus calculated from the tensile stress at 10% elongation in spoke 40 is less than 3 MPa, sufficient rigidity cannot be obtained, and adjacent spokes 40 in the tire circumferential direction C may come into contact with each other. On the other hand, if the tensile modulus calculated from the tensile stress at 10% elongation exceeds 12 MPa, the rigidity becomes excessively high, resulting in a deterioration of ride comfort.

[0039] Elastic materials used as the base material for spoke 40 include thermoplastic elastomers, cross-linked rubber, and other resins.

[0040] Examples of thermoplastic elastomers include polyester elastomers, polyolefin elastomers, polyamide elastomers, polystyrene elastomers, polyvinyl chloride elastomers, and polyurethane elastomers.

[0041] The rubber material used to make up the crosslinked rubber can be either natural rubber or synthetic rubber. Examples of synthetic rubbers include styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IIR), nitrile rubber (NBR), hydrogenated nitrile rubber (hydrogenated NBR), chloroprene rubber (CR), ethylene propylene rubber (EPDM), fluororubber, silicone rubber, acrylic rubber, and urethane rubber. Two or more of these rubber materials may be used in combination as needed.

[0042] Other resins include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include polyethylene resin, polystyrene resin, and polyvinyl chloride resin. Examples of thermosetting resins include epoxy resin, phenolic resin, polyurethane resin, silicone resin, polyimide resin, and melamine resin.

[0043] From the viewpoint of moldability, processability, and cost, polyurethane resin is preferably used for the spokes 40 among the elastic materials mentioned above. Foamed materials can also be used as the elastic material. That is, foamed thermoplastic elastomers, crosslinked rubbers, and other resins can be used.

[0044] Furthermore, the elastic material used as the base material for the spokes 40 may be reinforced with reinforcing fibers. Examples of reinforcing fibers include long fibers, short fibers, woven fabrics, and nonwoven fabrics. Examples of types of reinforcing fibers include rayon cord, polyamide cord such as nylon-6,6, polyester cord such as polyethylene terephthalate, aramid cord, glass fiber cord, carbon fiber, and steel cord.

[0045] Furthermore, reinforcement of elastic materials is not limited to reinforcement with reinforcing fibers. For example, reinforcement may be carried out by adding granular fillers. Examples of granular fillers that can be added include carbon black, silica, ceramics such as alumina, and other inorganic material fillers.

[0046] Incidentally, it is preferable that the inner annular portion 20 and the outer annular portion 30 described above are formed from the same resin material as the spokes 40. In that case, the inner annular portion 20, the outer annular portion 30, and the spokes 40 can be integrally molded, for example, by a casting method.

[0047] The tread 50 is provided on the outer circumferential surface of the outer annular portion 30. The tread 50 constitutes the outermost part of the non-pneumatic tire 1. The tread 50 includes tread rubber 51. The tread rubber 51 has a tread surface 51a on its outer surface that contacts the road surface. There are no particular restrictions on the type of rubber material used for the tread rubber 51; general vulcanized rubber used for the treads of vehicle tires can be used. The tread surface 51a of the tread rubber 51 is provided with a tread pattern formed by multiple grooves and flat areas, similar to conventional pneumatic tires. The tread rubber 51 may also be composed of multiple layers of rubber with different components and properties (for example, two or three layers). Furthermore, the tread 50 may be formed from resin.

[0048] The non-pneumatic tire 1 of this embodiment may further include a reinforcing layer, which is not shown. The reinforcing layer may be embedded in the outer annular portion 30. Alternatively, the reinforcing layer may be provided between the outer annular portion 30 and the tread 50. The reinforcing layer is a cylindrical layer extending along the tire circumferential direction C.

[0049] The reinforcing layer is evenly distributed around the entire circumference of the tire to suppress buckling, where the outer annular portion 30 bends in the tire radial direction X at the center of the tire width direction Y. The reinforcing layer is constructed, for example, by arranging steel cords so that they are roughly parallel to the tire width direction Y. A cylindrical metal ring, a high-modulus resin ring, etc., may be used as the reinforcing layer. For example, a fiber-reinforced plastic (FRP) ring such as carbon fiber reinforced plastic (CFRP) or glass fiber reinforced plastic (GFRP) may be used as the reinforcing layer. The addition of a reinforcing layer ensures the rigidity of the non-pneumatic tire 1 and improves the contact of the tread 50 with the road surface.

[0050] Figure 4 is a schematic unfolded diagram showing the division of pitch elements in the tread pattern of the tread 50. In Figure 4, the vertical direction of the paper is the tire circumferential direction C, and the horizontal direction of the paper is the tire width direction Y. Figure 4 corresponds to a view of a part of the outer surface of the tread 50 in, for example, the V region of Figure 1, as seen from the outer circumference of the tire.

[0051] The tread 50 has a tread pattern in which multiple pitch elements (pattern constituent units) with different pitch lengths P1 are arranged in a first arrangement pattern along the tire circumferential direction C.

[0052] The first arrangement pattern of this embodiment is a pattern in which multiple pitch elements, patterns TS, TM, and TL, are arranged in a so-called variable pitch. Here, variable pitch means arranging the pitch elements that are used repeatedly with different pitch lengths P1. The pitch length P1 in the first arrangement pattern is determined by the tire circumferential lengths of the patterns TS, TM, and TL as pitch elements. Preferably, the multiple pitch elements of the tread pattern are arranged in a variable pitch having at least three or more different pitch lengths P1.

[0053] The first array pattern of this embodiment comprises a plurality of pitch elements having at least three different pitch lengths P1. Specifically, the pitch lengths P1 of the pitch elements constituting the first array pattern include at least three types: pitch length S1, pitch length M1 longer than pitch length S1, and pitch length L1 longer than pitch length M1. That is, the first array pattern includes a pitch element TS with pitch length S1, a pitch element TM with pitch length M1 longer than pitch length S1, and a pitch element TL with pitch length L1 longer than pitch length M1. These plurality of pitch elements having different pitch lengths P1 are distributed and arranged in the tire circumferential direction C. In this embodiment, as shown in Figure 4, the pitch elements are arranged in the order TM, TS, TM, TL, TM, TS. In this way, it is preferable that the plurality of pitch elements having different pitch lengths P1 are arranged irregularly in the tire circumferential direction.

[0054] The first arrangement pattern of this embodiment includes an arrangement order in which a first pitch element, a second pitch element placed next to the first pitch element and having a pitch length different from that of the first pitch element, and a third pitch element placed next to the second pitch element and having a pitch length different from that of the second pitch element are arranged in that order. For example, the first arrangement pattern includes an arrangement order in which a pitch element TS with a pitch length S1, a pitch element TM placed next to the pitch element TS and having a pitch length M1 different from that of the pitch element TS and having a pitch length L1 different from that of the pitch element TM and having a pitch length L1 different from that of the pitch element TM are arranged. The first arrangement pattern may include an arrangement order in which a first pitch element (e.g., pitch element TS), a second pitch element (e.g., pitch element TM) positioned next to the first pitch element and having a different pitch length than the first pitch element, a third pitch element (e.g., pitch element TL) positioned next to the second pitch element and having a different pitch length than the second pitch element, and a fourth pitch element (e.g., pitch element TM) positioned next to the third pitch element and having a different pitch length than the third pitch element are arranged in that order. In this case, non-adjacent pitch elements, such as the second and fourth pitch elements, may have the same pitch length. By including such a configuration, the frequency components of pitch noise during tire rolling can be effectively dispersed. During tire rolling, noise at frequencies corresponding to the arrangement of pitch elements in the tread pattern becomes a problem, but according to this embodiment, the frequency of pitch noise during tire rolling can be dispersed, and the pitch noise caused by the arrangement of pitch elements in the tread pattern can be reduced.

[0055] Figure 5 is an enlarged view of section V in Figure 1, and is a partial side view of a non-pneumatic tire. Figure 6 is a diagram showing the position of the connection points of the spokes 40 connected to the inner circumferential surface of the outer annular portion 30, viewed through a schematic unfolded diagram of the tread pattern in Figure 4. In other words, Figure 6 is a diagram showing the relationship between the first arrangement pattern and the second arrangement pattern, and the hypothetical positions of the connection points of the spokes 40 projected onto the surface of the tread pattern are shown by dashed lines.

[0056] Multiple spokes 40 are arranged along the tire circumferential direction C with a pitch corresponding to the first arrangement pattern of the tread pattern. Specifically, the connecting portions 412 and 422 of multiple spokes 41 and 42 are arranged along the tire circumferential direction C with different pitch lengths P2, in a second arrangement pattern with a pitch corresponding to the first arrangement pattern of the tread pattern.

[0057] In this embodiment, the first spokes 41 and the second spokes 42 are arranged alternately in the circumferential direction of the tire. Therefore, the pitch length P2 of the connection portion of the multiple spokes 40 is determined based on the position of the first outer connection portion 412 of the first spoke 41 and the position of the second outer connection portion 422 of the second spoke 42 adjacent to the first outer connection portion 412 of the first spoke 41.

[0058] The connections of the multiple spokes 40 in this embodiment are arranged along the tire circumferential direction C in a so-called variable pitch. That is, the second arrangement pattern is a variable pitch arrangement pattern. Here, variable pitch means arranging the connections of the spokes 40 with different pitch lengths P2 as pitch elements. The pitch length P2 in the second arrangement pattern is defined by the tire circumferential length between the center positions of the connections of adjacent spokes 40 in the tire circumferential direction C. In other words, when the distance between the connections of two adjacent spokes 40 in the tire circumferential direction C is defined as the spoke spacing G (described later), the pitch length P2 is the spoke spacing G plus half the length corresponding to the thickness t of the connection of one spoke 40 adjacent to the spoke spacing G, and half the length corresponding to the thickness t of the connection of the other spoke 40 adjacent to the spoke spacing G.

[0059] The connections between the multiple spokes 40 are arranged in a variable pitch having multiple pitch lengths P2 corresponding to the variable pitch of the tread pattern. Preferably, the connections between the multiple spokes 40 are arranged in a variable pitch having at least three or more different pitch lengths P2 corresponding to the variable pitch of the tread pattern.

[0060] The second arrangement pattern of this embodiment has at least three different pitch lengths P2. Specifically, the pitch lengths P2 constituting the second arrangement pattern include at least three types: pitch length S2, pitch length M2 which is longer than pitch length S2, and pitch length L2 which is longer than pitch length M2. These different pitch lengths P2 are distributed in the tire circumferential direction C. In this embodiment, as shown in Figure 5, the pitch lengths P2 are arranged in the order M2, S2, M2, L2, M2, S2. In this way, it is preferable that the multiple different pitch lengths are arranged irregularly in the tire circumferential direction.

[0061] The second arrangement pattern of this embodiment includes an arrangement order in which a first pitch, a second pitch located next to the first pitch and having a different pitch length from the first pitch, and a third pitch located next to the second pitch and having a different pitch length from the second pitch are arranged in that order. For example, the second arrangement pattern includes an arrangement order in which a first pitch with pitch length S2, a second pitch located next to the first pitch and having a different pitch length M2 from pitch length S2, and a third pitch located next to the second pitch and having a different pitch length L2 from pitch length M2 are arranged in that order. The second arrangement pattern may include an arrangement order in which a first pitch (for example, a pitch with pitch length S2), a second pitch located next to the first pitch and having a different pitch length (for example, pitch length M2), a third pitch located next to the second pitch and having a different pitch length (pitch length L2), and a fourth pitch located next to the third pitch and having a different pitch length (pitch length M2) are arranged in that order. In this case, non-adjacent pitches, for example, the second pitch and the fourth pitch, may have the same pitch length. By including such a configuration, the frequency components of pitch noise during tire rolling can be effectively dispersed. During tire rolling, noise with frequencies corresponding to the arrangement position of the outer connection part of the spokes becomes a problem, but according to this embodiment, the frequency of pitch noise during tire rolling can be dispersed, and the pitch noise generated by the spokes 40 striking the road surface can be reduced.

[0062] In this embodiment, the connection points of the multiple spokes 40 are arranged with different pitch lengths P2 along the tire circumferential direction C by varying the spoke spacing G, which is the distance between adjacent connection points in the tire circumferential direction C.

[0063] As shown in Figure 5, in this embodiment, the non-pneumatic tire 1 has uneven spacing G between adjacent spokes 40 in the tire circumferential direction C. In the following description, the spacing G between spokes 40 will be referred to as the spoke spacing G. In this embodiment, the spoke spacing G is the distance between the first outer connection portion 412 of the first spoke 41 adjacent in the tire circumferential direction C and the second outer connection portion 422 of the second spoke 42. More specifically, as shown in Figure 5, the spoke spacing G is the distance in the tire circumferential direction C between the first outer peripheral end 412c on the side of the second outer connection portion 422 of the boundary between the first outer connection portion 412 and the inner circumferential surface of the outer annular portion 30 of the first outer connection portion 412 and the second outer peripheral end 422c on the side of the first outer connection portion 412 of the boundary between the second outer connection portion 422 and the inner circumferential surface of the outer annular portion 30 of the first outer connection portion 422 of the first outer connection portion 412.

[0064] The spoke spacing G in this embodiment includes at least three types: spacing S, spacing M which is longer than spacing S, and spacing L which is longer than spacing M. These three types of spoke spacing G are distributed in the tire circumferential direction C. That is, the spoke spacing G, which represents the gap between the first outer peripheral end 412c of the first outer connecting portion 412 and the second outer peripheral end 422c of the second outer connecting portion 422 adjacent to the tire circumferential direction C, is arranged irregularly in the tire circumferential direction C so that the three types of spacing S, spacing M, and spacing L are not periodic around the entire circumference of the tire 1. This makes it easy to arrange the connecting portions of multiple spokes 40 with different pitch lengths P2 along the tire circumferential direction, even when the plate thickness of the spokes 40 is constant.

[0065] Furthermore, it is preferable that the spoke spacing G be set to 2 mm or more and 30 mm or less. The spoke spacing G may be, for example, spacing S = 7 mm, spacing M = 9 mm, and spacing L = 11 mm, but is not limited to this. Furthermore, it is preferable that the tensile modulus calculated from the tensile stress when the spoke 40 is elongated by 10% is 3 MPa or more, and that the minimum spoke spacing G is 2.5 mm or more. This makes it possible to suppress situations in which adjacent spokes 40 in the tire circumferential direction C come into contact with each other. As a result, it is possible to suppress the reduction in tire durability due to spoke damage.

[0066] In this embodiment, the spoke spacing G includes an arrangement order in which a first spacing, a second spacing located next to the first spacing and at a different distance from the first spacing, and a third spacing located next to the second spacing and at a different distance from the second spacing are arranged in that order. For example, the spoke spacing G includes an arrangement order in which spacing S, spacing M located next to spacing S and at a different distance from spacing S, and spacing L located next to spacing M and at a different distance from spacing M are arranged in that order. The spoke spacing G may also include an arrangement order in which a first spacing (e.g., spacing S), a second spacing (spacing M) located next to the first spacing and at a different distance from the first spacing, a second spacing (spacing L) located next to the second spacing and at a different distance from the second spacing, and a fourth spacing (spacing M) located next to the third spacing and at a different distance from the third spacing are arranged in that order. By including such a configuration, the frequency components of pitch noise during tire rolling can be effectively dispersed.

[0067] As shown in Figures 5 and 6, the positions C in the tire circumferential direction at the boundaries of the multiple pitch elements TS, TM, and TL of the tread pattern may coincide with the positions C in the tire circumferential direction at the connections of the multiple spokes 40. Also, as shown in Figures 5 and 6, when the number of multiple pitch elements TS, TM, and TL of the tread pattern is defined as the first number, and the number of connections of the multiple spokes 40 is defined as the second number, the first number may be the same as the second number. However, the relationship between the first number and the second number is not limited to this. For example, the first number may be a positive integer multiple of the second number, or the second number may be a positive integer multiple of the first number. It is preferable that this relationship exists over the entire circumference of the non-pneumatic tire 1, but it is sufficient if it is substantially this relationship. For example, it is preferable that this relationship exists in a total area of ​​more than half of the entire circumference of the non-pneumatic tire 1.

[0068] Furthermore, it is preferable that the arrangement order of the pitch lengths P1 of the multiple pitch elements defined by the first arrangement pattern corresponds to the arrangement order of the pitch lengths P2 of the connection parts of the multiple spokes defined by the second arrangement pattern. For example, in this embodiment, the arrangement order of the pitch lengths P1 of the multiple pitch elements defined by the first arrangement pattern is M1, S1, M1, L1, M1, S1, and the arrangement order of the pitch lengths P2 of the connection parts of the multiple spokes defined by the second arrangement pattern is M2, S2, M2, L2, M2, S2. The order of these pitch lengths in terms of magnitude is consistent.

[0069] It should be noted that the dimensions of the pitch lengths S1, M1, and L1 of the patterns TS, TM, and TL, which are multiple pitch elements located on the surface of the tread 50, do not strictly coincide with the dimensions of the pitch lengths S2, M2, and L2 of the connecting parts of the spokes 40 located on the inner circumferential surface of the outer annular portion 30. This is because the radial positions of the circumferential surface on which they are arranged are different. For example, the dimensions of the pitch lengths S1, M1, and L1 of the first arrangement pattern on the surface of the tread 50 and the dimensions of the pitch lengths S2, M2, and L2 of the second arrangement pattern at the connecting parts of the spokes 40 may be proportional to the radial positions of the circumferential surface on which they are arranged. Furthermore, if the pitch based on an angle relative to the tire rotation axis is expressed as angular pitch, it can also be said that the connecting parts of the multiple spokes 40 are arranged along the circumferential direction of the tire in a second arrangement pattern with an angular pitch that substantially coincides with the angular pitch based on the first arrangement pattern.

[0070] Here, the stiffness of the tread 50 varies depending on the pitch length P1 of the pitch elements of the tread pattern. For example, the bending stiffness (tire longitudinal stiffness) of the tread 50 extending in the tire circumferential direction C, against a compressive force in the tire radial direction X applied from the outside of the tire, varies depending on the pitch length P1 of the pitch elements of the tread pattern. Specifically, the shorter the pitch element with pitch length P1, the higher the frequency of lateral grooves and other elements in the tread pattern, resulting in lower tire longitudinal stiffness in the tire circumferential direction C of the tread 50. For example, if the stiffness of the part where pattern TS is located as a pitch element is RS1, the stiffness of the part where pattern TM is located is RM1, and the stiffness of the part where pattern TL is located is RL1, then the relationship between them is RS1 <RM1<RL1となる。

[0071] On the other hand, the support structure for the non-pneumatic tire 1, which is composed of the outer annular portion 30, spokes 40, and inner annular portion 20, has increased longitudinal tire rigidity in the portion where the connection portion of the spokes 40 is located. Therefore, the shorter the pitch length P2 at which the connection portions of the spokes 40 are located, the higher the longitudinal tire rigidity of the support structure in the tire circumferential direction C. For example, if the rigidity of the portion where the connection portions of the spokes 40 are located with a pitch length S2 is RS2, the rigidity of the portion where the connection portions of the spokes 40 are located with a pitch length M2 is RM2, and the rigidity of the portion where the connection portions of the spokes 40 are located with a pitch length L2 is RL2, then the relationship between them is RS2 > RM > RL.

[0072] In this embodiment, the tread 50 has a tread pattern in which a plurality of pitch elements with different pitch lengths P1 are arranged in a first arrangement pattern along the tire circumferential direction C. The plurality of spokes 40 are arranged along the tire circumferential direction at a pitch corresponding to the first arrangement pattern. As a result, the rigidity of the tread 50 and the rigid and low parts of the support structure including the spokes 40 mutually compensate for each other, reducing pitch noise and making the rigidity in the tire circumferential direction C uniform. Furthermore, uneven wear of the tread 50 can be suppressed. Therefore, the reduction in tire durability can be suppressed. In addition, the uniformity of the non-pneumatic tire 1 can be improved.

[0073] Figure 7 is a diagram corresponding to Figure 6 and illustrates a specific example of this embodiment, showing a modified arrangement of the first and second arrangement patterns. Figure 7 shows a specific example of a tread pattern as the first arrangement pattern. The surface of the tread 50 shown in Figure 7 is provided with a plurality of grooves, including a center main groove 52A, a center lateral groove 52B, a shoulder main groove 52C, a shoulder lateral groove 52D, and a narrow groove 52E.

[0074] The first arrangement pattern of this modified example is a pattern in which multiple pitch elements, patterns TSA, TSB, TMA, TMB, TLA, and TLB, are arranged in a so-called variable pitch.

[0075] Specifically, the first arrangement pattern of this modified example includes pitch elements TSA and TSB with a pitch length S1, pitch elements TMA and TMB with a pitch length M1 longer than S1, and pitch elements TLA and TLB with a pitch length L1 longer than M1. These multiple pitch elements with different pitch lengths are distributed in the tire circumferential direction C. In this modified example, as shown in Figure 7, the pitch elements are arranged in the order TLA, TLB, TLA, TLB, TMA, TMB, TMA, TMB, TSA, TSB, TSA, TSB. For example, such a group of pitch elements may be arranged at other locations on the outer circumference of the tire, or it may be arranged repeatedly.

[0076] In this modified example, the connections between the multiple spokes 40 are arranged in a variable pitch having multiple pitch lengths corresponding to the variable pitch of the tread pattern.

[0077] Specifically, as shown in Figure 7, the multiple spokes 40 of this modified example are arranged along the tire circumferential direction C with a pitch corresponding to the first arrangement pattern of the tread pattern: TLA, TLB, TLA, TLB, TMA, TMB, TMA, TMB, TSA, TSB, TSA, TSB. That is, the connection points of the multiple spokes 40 are arranged along the tire circumferential direction C with a second arrangement pattern having a pitch length corresponding to the order of pitch lengths of the first arrangement pattern: L1, L1, L1, L1, M1, M1, M1, M1, S1, S1, S1, S1.

[0078] In this embodiment as well, the first spokes 41 and the second spokes 42 are arranged alternately in the circumferential direction of the tire. Therefore, the pitch length of the connection portion of the multiple spokes 40 is determined based on the position of the first outer connection portion 412 of the first spoke 41 and the position of the second outer connection portion 422 of the second spoke 42 adjacent to the first outer connection portion 412 of the first spoke 41.

[0079] In the first arrangement pattern of this modified example, the sets of TLA and TLB, TMA and TMB, and TSA and TSB can each be considered as a single set of pitch elements. Alternatively, the sets of TLA, TLB, TLA and TLB, TMA, TMB, TMA and TMB, and TSA, TSB, TSA and TSB can each be considered as a single set of pitch elements. Even in this case, the tread 50 has a tread pattern in which multiple pitch elements with different pitch lengths P1 are arranged in the first arrangement pattern along the tire circumferential direction C, and the multiple spokes 40 are arranged in a variable pitch along the tire circumferential direction with a pitch corresponding to the first arrangement pattern.

[0080] As described above, in this modified example as well, the tread 50 has a tread pattern in which multiple pitch elements with different pitch lengths are arranged in a first arrangement pattern along the tire circumferential direction C. The multiple spokes 40 are arranged along the tire circumferential direction with a pitch corresponding to the first arrangement pattern. This makes it possible to effectively disperse the frequency components of pitch noise during tire rolling while uniformizing the rigidity in the tire circumferential direction C. Furthermore, uneven wear of the tread 50 can be suppressed. In addition, the uniformity of the non-pneumatic tire 1 can be improved.

[0081] The non-pneumatic tire 1 of this embodiment provides the following effects.

[0082] (1) The non-pneumatic tire 1 according to this embodiment comprises an inner annular portion 20, an outer annular portion 30 arranged coaxially with the inner annular portion 20 on the outer circumference side of the inner annular portion 20, a plurality of spokes 40 connecting the inner annular portion 20 and the outer annular portion 30 and arranged along the tire circumferential direction, and a tread 50 provided on the outer circumferential surface of the outer annular portion 30, wherein the tread 50 has a tread pattern in which a plurality of pitch elements with different pitch lengths P1 are arranged in a first arrangement pattern along the tire circumferential direction, and the plurality of spokes 40 are arranged along the tire circumferential direction with a pitch corresponding to the first arrangement pattern.

[0083] This reduces pitch noise while improving the uniformity of tire rigidity.

[0084] (2) In the non-pneumatic tire 1 of this embodiment, each of the multiple spokes 40 has connecting parts 412 and 422 that connect to the outer annular part 30, and the connecting parts 412 and 422 of the multiple spokes are arranged along the circumferential direction of the tire with different pitch lengths P2 in a second arrangement pattern with a pitch corresponding to the first arrangement pattern.

[0085] This reduces pitch noise while improving the uniformity of tire rigidity.

[0086] (3) In the non-pneumatic tire 1 of this embodiment, the second arrangement pattern includes an arrangement order in which a first pitch, a second pitch located next to the first pitch and having a different pitch length from the first pitch, and a third pitch located next to the second pitch and having a different pitch length from the second pitch are arranged in that order.

[0087] This disperses the frequency of pitch noise during tire rolling, further reducing the pitch noise caused by the spokes 40 striking the road surface.

[0088] (4) In the non-pneumatic tire 1 of this embodiment, the multiple pitch elements of the tread pattern are arranged in a variable pitch having at least three or more pitch lengths P1, and the connecting portions of the multiple spokes 40 are arranged in a variable pitch having at least three or more pitch lengths P2 corresponding to the variable pitch of the tread pattern.

[0089] This allows for a further reduction in pitch noise while improving the uniformity of tire rigidity.

[0090] (5) In the non-pneumatic tire 1 of this embodiment, the arrangement order of the pitch lengths P1 of the multiple pitch elements defined by the first arrangement pattern corresponds to the arrangement order of the pitch lengths P2 of the connecting parts of the multiple spokes 40 defined by the second arrangement pattern.

[0091] This allows for a more effective improvement in the uniformity of tire stiffness.

[0092] (6) In the non-pneumatic tire 1 of this embodiment, the circumferential positions of the boundaries of the multiple pitch elements of the tread pattern and the circumferential positions of the connections of the multiple spokes 40 coincide.

[0093] This allows for a more effective improvement in the uniformity of tire stiffness.

[0094] (7) In the non-pneumatic tire 1 of this embodiment, when the number of pitch elements of the tread pattern is set to a first number and the number of connection points of the spokes 40 is set to a second number, the first number is a positive integer multiple of the second number, or the second number is a positive integer multiple of the first number.

[0095] This improves the uniformity of tire rigidity.

[0096] (8) In the non-pneumatic tire 1 of this embodiment, the first number is the same as the second number.

[0097] This improves the uniformity of tire rigidity.

[0098] (9) In the non-pneumatic tire 1 of this embodiment, the connection portions of the multiple spokes 40 are arranged with different pitch lengths P2 along the tire circumferential direction by making the spoke spacing G, which is the distance between adjacent connection portions in the tire circumferential direction, different.

[0099] This makes it easy to arrange the connection points of multiple spokes 40 with different pitch lengths along the circumferential direction of the tire, even when the thickness of the spokes 40 is constant.

[0100] (10) In the non-pneumatic tire 1 of this embodiment, the spokes 40 include a first spoke 41 inclined toward one side in the tire axial direction and a second spoke 42 inclined toward the opposite side from the first spoke 41, the first spokes 41 and the second spokes 42 being arranged alternately in the tire circumferential direction, and the pitch length P2 of the connection portions of the plurality of spokes 40 is determined based on the position of the connection portion of the first spoke 41 and the position of the connection portion of the second spoke 42 adjacent to the connection portion of the first spoke 41.

[0101] As a result, the first spoke 41 and the second spoke 42 are arranged in a roughly X shape when viewed from a direction along the tire circumferential direction C. Since the first spoke 41 and the second spoke 42 are each inclined in the direction of the tire axis, excessive rigidity is suppressed, and ride comfort is improved.

[0102] In this embodiment, the non-pneumatic tire 1 has multiple spokes 40 whose connection points are arranged along the tire circumferential direction C with different pitch lengths P2, corresponding to the pitch elements of the tread pattern, and the tensile modulus calculated from the tensile stress of the spokes 40 when they are elongated by 10% is between 3 MPa and 12 MPa. Furthermore, the spokes 40 are configured such that the first spokes 41 and the second spokes 42 are arranged in a substantially X shape when viewed from a direction along the tire circumferential direction C. This reduces pitch noise, improves the uniformity of rigidity in the tire circumferential direction, suppresses contact between adjacent spokes 40, and prevents a reduction in tire durability. In addition, it is possible to maintain a good ride comfort.

[0103] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and modifications, improvements, etc., made to the extent that the objectives of the present invention can be achieved are also included within the scope of the present invention. For example, the pitch length P1 of the first array pattern is not limited to three types: pitch length S1, pitch length M1, and pitch length L1. At least two types of pitch lengths may be set, and there may be four or more types. The pitch length P2 of the second array pattern is not limited to three types: pitch length S2, pitch length M2, and pitch length L2. At least two types of pitch lengths may be set, and there may be four or more types. In other words, the first arrangement pattern preferably includes at least a first pitch element and a second pitch element having a pitch length different from the pitch length of the first pitch element, and the first and second pitch elements are arranged so as not to be periodic. Furthermore, the pitch length of the second arrangement pattern preferably includes at least a first pitch length and a second pitch length longer than the first pitch length, and the connection portions of the spokes 40 are arranged so as not to be periodic between the portion forming the first pitch length and the portion forming the second pitch length. The spokes 40 include a first spoke 41 and a second spoke 42 that intersect in a roughly X-shape when viewed from a direction along the tire circumferential direction C, but the spokes 40 are not limited to this, and the spokes 40 may consist of plate-shaped portions that extend straight in the tire radial direction X. The plate thickness t and plate width w of the spoke 40 do not have to be constant; for example, the plate thickness t may gradually increase or the plate width w may gradually increase as you move from the inner annular portion 20 to the outer annular portion 30. [Explanation of Symbols]

[0104] 1. Non-pneumatic tires 20 Inner annular portion 30 Outer annular part 40 spokes 41 First spoke 42 Second spoke 412 First outer connection part (connection part) 422 Second outer connection part (connection part) 50 tread C Tire circumferential direction Y tire width direction

Claims

1. The inner annular part, An outer annular portion is arranged coaxially with the inner annular portion on the outer circumferential side of the inner annular portion, Multiple spokes are arranged along the circumferential direction of the tire, connecting the inner annular portion and the outer annular portion. A non-pneumatic tire comprising a tread provided on the outer circumferential surface of the outer annular portion, The tread has a tread pattern in which a plurality of pitch elements with different pitch lengths are arranged in a first arrangement pattern along the circumferential direction of the tire. The plurality of spokes are arranged along the circumferential direction of the tire at a pitch corresponding to the first arrangement pattern. The number of spokes is between 80 and 300. Each of the aforementioned spokes has a connecting portion that connects to the outer annular portion, The connection points of the plurality of spokes are arranged in a second arrangement pattern with a pitch corresponding to the first arrangement pattern, with varying pitch lengths along the circumferential direction of the tire. A non-pneumatic tire in which the circumferential positions of the boundaries of the multiple pitch elements of the tread pattern coincide with the circumferential positions of the connections of the multiple spokes.

2. The non-pneumatic tire according to claim 1, wherein the second arrangement pattern includes an arrangement order in which a first pitch, a second pitch located next to the first pitch and having a different pitch length from the first pitch, and a third pitch located next to the second pitch and having a different pitch length from the second pitch are arranged in that order.

3. The multiple pitch elements of the tread pattern are arranged in a variable pitch having at least three different pitch lengths. The non-pneumatic tire according to claim 1 or claim 2, wherein the connection portions of the plurality of spokes are arranged in a variable pitch having at least three different pitch lengths corresponding to the variable pitch of the tread pattern.

4. A non-pneumatic tire according to any one of claims 1 to 3, wherein the arrangement order of the pitch lengths of a plurality of pitch elements defined by the first arrangement pattern corresponds to the arrangement order of the pitch lengths of the connection portions of a plurality of spokes defined by the second arrangement pattern.

5. A non-pneumatic tire according to any one of claims 1 to 4, wherein when the number of pitch elements in the tread pattern is a first number and the number of connection parts of the plurality of spokes is a second number, the first number is a positive integer multiple of the second number, or the second number is a positive integer multiple of the first number.

6. The non-pneumatic tire according to claim 5, wherein the first number is the same as the second number.

7. The non-pneumatic tire according to any one of claims 1 to 6, wherein the connection portions of the plurality of spokes are arranged with different pitch lengths along the circumferential direction of the tire by varying the inter-spoke spacing, which is the distance between adjacent connection portions in the circumferential direction of the tire.

8. The aforementioned spokes are It includes a first spoke that is inclined toward one side in the axial direction of the tire, and a second spoke that is inclined toward the opposite side from the first spoke, The first spoke and the second spoke are arranged alternately in the circumferential direction of the tire. The non-pneumatic tire according to any one of claims 1 to 7, wherein the pitch length of the connection portions of the plurality of spokes is determined based on the position of the connection portion of a first spoke and the position of the connection portion of a second spoke adjacent to the connection portion of the first spoke.

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