Non-pneumatic tires

Abstract

This suppresses deterioration of maneuverability and uneven wear in the shoulder portions of the tread members. [Solution] A non-pneumatic tire 1 comprises an inner cylinder, an outer cylinder 12 surrounding the inner cylinder from the outside in the tire radial direction, an elastically deformable connecting member 13 connecting the inner cylinder and the outer cylinder 12 to each other, and a tread member 14 provided on the outer circumferential surface of the outer cylinder 12, wherein the outer circumferential surface 14f of the tread member 14 has a curved shape that is convex outward in the tire radial direction when viewed in cross-sectional view in the tire width direction, and the curve is made up of a plurality of circular arcs AC1 to AC3 with different radii of curvature, and the radii of curvature R1 to R3 of the plurality of circular arcs AC1 to AC3 are smaller for the circular arcs on the outer circumferential surface 14f of the tread member 14 that are on the outside in the tire width direction.

Description

[Technical Field]

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

[0002] In order to solve the problem of punctures, which is an unavoidable issue with conventional pneumatic tires, non-pneumatic tires have been proposed in recent years. For example, Patent Document 1 discloses a non-pneumatic tire comprising an inner cylinder, an outer cylinder surrounding the inner cylinder from the outside in the tire radial direction, an elastically deformable connecting member connecting the inner cylinder and the outer cylinder to each other, and a tread (tread member) fitted onto the outer cylinder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-57476 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in non-pneumatic tires such as those described in Patent Document 1 above, the rigidity of the outer cylinder is very high and the amount of deformation is small. For example, if the outer surface of the tread member is formed in a straight line (flat) or a circular arc with a large radius of curvature in a cross-sectional view along the tire width direction, it has been found that the contact pressure on the shoulder portion of the tread member can locally increase, especially when a slip angle or camber angle is acquired while the vehicle is running, which can lead to a decrease in handling performance and make uneven wear more likely to occur on the shoulder portion.

[0005] Therefore, the present invention aims to provide a non-pneumatic tire that can suppress a decrease in maneuverability and the occurrence of uneven wear on the shoulder portion of the tread member. [Means for solving the problem]

[0006] The means for achieving the above objectives are as follows:

[0007] (1) The non-pneumatic tire of the present invention is A non-pneumatic tire comprising an inner cylinder, an outer cylinder surrounding the inner cylinder from the outside in the tire radial direction, an elastically deformable connecting member connecting the inner cylinder and the outer cylinder to each other, and a tread member provided on the outer circumferential surface of the outer cylinder, an outer peripheral surface of the tread member having a curved shape that is convex outward in the tire radial direction in a cross-sectional view in the tire width direction, the curve is a series of multiple arcs each having a different radius of curvature, The radius of curvature of the plurality of arcs is smaller toward the outer side in the tire width direction on the outer circumferential surface of the tread element. According to the non-pneumatic tire of the present invention, it is possible to suppress deterioration in maneuverability and occurrence of uneven wear in the shoulder portions of the tread members.

[0008] (2) In the non-pneumatic tire of (1) above, Preferably, the radius of curvature of the shoulder arc, which is the outermost arc in the tire width direction, is 0.3 times or less the radius of curvature of the center arc, which is the arc at the center in the tire width direction. In this case, it is possible to further suppress the deterioration of maneuverability and the occurrence of uneven wear in the shoulder portions of the tread members.

[0009] (3) In the non-pneumatic tire described in (1) or (2) above, It is preferable that the distance in the tire width direction from the tire width center to a connection point between a center arc, which is the arc at the tire width center, and an intermediate arc, which is the arc adjacent to the center arc on the tire width direction outer side, is 2 / 3 or less of the distance in the tire width direction between the tire width center and the tire width direction outer end on the outer peripheral surface of the tread element. In this case, the decrease in handling performance and the occurrence of uneven wear on the shoulder portion of the tread material can be more effectively suppressed.

[0010] (4) In any of the non-pneumatic tires described in (1) to (3) above, The aforementioned curve may be a series of three circular arcs with different radii of curvature. In this case, it is possible to effectively prevent deterioration in maneuverability and uneven wear in the shoulder portions of the tread element without making the shape of the outer peripheral surface of the tread element too complicated. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a non-pneumatic tire that can suppress deterioration in maneuverability and occurrence of uneven wear in shoulder portions of tread members. [Brief explanation of the drawings]

[0012] [Figure 1] This is a side view of a non-pneumatic tire according to one embodiment of the present invention. [Figure 2] Figure 1 is a side view showing an example of a tire-rim assembly using a non-pneumatic tire. [Figure 3] FIG. 2 is a perspective view of the non-pneumatic tire of FIG. 1. [Figure 4] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 5] FIG. 5 is an enlarged cross-sectional view taken along line B-B in FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0013] The non-pneumatic tire according to the present invention can be mounted on any type of vehicle and is particularly suitable for mounting on, for example, bicycles, motorcycles, automobiles including light vehicles, and handle-type electric wheelchairs.

[0014] Hereinafter, embodiments of the non-pneumatic tire according to the present invention will be described with reference to the drawings. In each drawing, the same members and parts are designated by the same reference numerals. In this specification, the term "tire width direction" refers to a direction parallel to the central axis O that is the rotation axis of the non-pneumatic tire 1, the term "tire circumferential direction" refers to a direction that rotates around the central axis O when viewed from the tire width direction, and the term "tire radial direction" refers to a direction perpendicular to the central axis O. In some drawings, the tire width direction is indicated by the symbol "WD," the tire circumferential direction is indicated by the symbol "CD," and the tire radial direction is indicated by the symbol "RD." In this specification, the side closer to the tire width direction center CL (i.e., the center in the tire width direction of a non-pneumatic tire, generally also referred to as the tire equatorial plane) along the tire width direction is referred to as the "inner side in the tire width direction," and the side farther from the tire width direction center CL along the tire width direction is referred to as the "outer side in the tire width direction." Furthermore, in this specification, the side closer to the center axis O along the tire radial direction is referred to as the "inner side in the tire radial direction," and the side farther from the center axis O along the tire radial direction is referred to as the "outer side in the tire radial direction."

[0015] Fig. 1 and Fig. 3 to Fig. 5 are drawings for explaining a non-pneumatic tire according to one embodiment of the present invention. Fig. 1 is a side view of the non-pneumatic tire according to one embodiment of the present invention, Fig. 3 is a perspective view of the non-pneumatic tire of Fig. 1, Fig. 4 is a cross-sectional view taken along line AA of Fig. 1, and Fig. 5 is an enlarged cross-sectional view between B-B of Fig. 4. FIG. 2 is a side view showing an example of a tire-rim assembly using the non-pneumatic tire of FIG.

[0016] 1 is mounted on a rim 2 to form a tire-rim assembly 3 as shown in Fig. 2, and the tire-rim assembly 3 is attached to an axle of a vehicle (not shown) via the rim 2 by, for example, bolts threaded into bolt holes 2a of the rim 2. That is, the non-pneumatic tire 1 is attached to the axle of a vehicle via the rim 2 and is put into use.

[0017] In this embodiment, the non-pneumatic tire 1 is formed in an annular shape, the rim 2 to which the non-pneumatic tire 1 is attached is formed in a disc shape, and the central axis of the rim 2 is configured to coincide with the central axis O of the non-pneumatic tire 1. Furthermore, in this embodiment, the tire widthwise center CL of the non-pneumatic tire 1 is configured to coincide with the tire widthwise center of the rim 2 on which the non-pneumatic tire 1 is mounted.

[0018] The non-pneumatic tire 1 has a function of absorbing vibrations transmitted from the ground to the axle, and the rim 2 has a function of connecting the axle and the non-pneumatic tire 1. The non-pneumatic tire 1 and the rim 2 may be made of different materials. For example, the non-pneumatic tire 1 may be made of a material with a relatively low elastic modulus to ensure vibration absorption performance, and the rim 2 may be made of a material with a higher elastic modulus than the non-pneumatic tire 1 to ensure robustness. Furthermore, for example, the rim 2 may be made of a material with a relatively low specific gravity to reduce the weight of the entire tire-rim assembly 3.

[0019] In this embodiment, as shown in Figures 1 to 3, the non-pneumatic tire 1 comprises an inner cylinder 11, an outer cylinder 12 surrounding the inner cylinder 11 from the outside in the tire radial direction, an elastically deformable connecting member 13 connecting the inner cylinder 11 and the outer cylinder 12 to each other, and a tread member 14 provided on the outer circumferential surface of the outer cylinder 12.

[0020] The elastic modulus of the material forming the inner cylindrical body 11, the outer cylindrical body 12, and the connecting member 13 can be, for example, 100 MPa or more and 1500 MPa or less.

[0021] In this embodiment, the inner cylindrical body 11 is attached to the axle via the rim 2, as shown in FIG. 2. In addition, in this embodiment, the outer cylindrical body 12 surrounds the inner cylindrical body 11 from the outer side in the tire radial direction, as shown in FIGS. 1 to 3. That is, the outer cylindrical body 12 surrounds the periphery of the inner cylindrical body 11 from the outer side in the tire radial direction. The central axes of the inner cylindrical body 11 and the outer cylindrical body 12 are arranged coaxially with the central axis O. In this embodiment, the inner cylindrical body 11, the outer cylindrical body 12, and the connecting member 13 are arranged with their respective centers in the tire width direction aligned with each other. In this embodiment, the inner cylindrical body 11, the outer cylindrical body 12, and the connecting member 13 are integrally formed from a thermoplastic resin. This allows the non-pneumatic tire 1 to be formed by injection molding, making it suitable for mass production. The thermoplastic resin may be, for example, a single resin, a mixture containing two or more resins, or a mixture containing one or more resins and one or more elastomers, and may further contain additives such as antioxidants, plasticizers, fillers, or pigments. The inner cylinder 11, the outer cylinder 12, and the connecting member 13 may be formed separately. The inner cylinder 11, the outer cylinder 12, and the connecting member 13 may also be formed from a material other than a thermoplastic resin.

[0022] In this embodiment, as shown in FIGS. 1 and 2 , a plurality of connecting members 13 are arranged between the inner cylindrical body 11 and the outer cylindrical body 12, so as to be point-symmetrical with respect to each other with respect to the central axis O. Adjacent connecting members 13 in the tire circumferential direction are arranged spaced apart and not in contact with each other. As shown in the figures, the connecting member 13 has a curved shape in side view, and is configured such that two portions 13a and 13c having a small inclination angle with respect to the tire radial direction are connected by a portion 13b having a large inclination angle with respect to the tire radial direction. As a result, the tire radially inner end of the portion 13a connected to the inner cylindrical body 11 is located on one side of the tire radially outer end of the portion 13c connected to the outer cylindrical body 12. This allows the connecting member 13 to be used as a leaf spring that easily elastically deforms in the tire radial direction.

[0023] In this embodiment, as shown in each drawing, the tread element 14 is provided on the outer peripheral surface of the outer cylindrical body 12. More specifically, in this embodiment, the tread element 14 is provided so as to cover the entire outer peripheral surface of the outer cylindrical body 12. Consequently, the tread element 14 is formed in a tubular shape extending in the tire width direction around the central axis O. The tread element 14 covers not only the outer peripheral surface of the outer cylindrical body 12 but also the tire radially outer end portions of the side surfaces of the outer cylindrical body 12 facing the tire width direction with the side portions 14s of the tread element 14 (see FIG. 5, etc.). In this embodiment, the elastic modulus of the material forming the tread element 14 is lower than the elastic modulus of the material forming other portions of the non-pneumatic tire 1. The tread element 14 is formed, for example, from natural rubber and / or vulcanized rubber obtained by vulcanizing a rubber composition, a thermoplastic material, or the like. From the viewpoint of wear resistance, it is preferable to form the tread element 14 from vulcanized rubber. Examples of the thermoplastic material include a thermoplastic elastomer and a thermoplastic resin. Examples of the thermoplastic elastomer include thermoplastic amide elastomer (TPA), thermoplastic ester elastomer (TPC), thermoplastic olefin elastomer (TPO), thermoplastic styrene elastomer (TPS), thermoplastic urethane elastomer (TPU), crosslinked thermoplastic rubber (TPV), and other thermoplastic elastomers (TPZ), which are specified in JIS K 6418. Examples of the thermoplastic resin include urethane resin, olefin resin, vinyl chloride resin, and polyamide resin.

[0024] In this embodiment, the outer peripheral surface 14f of the tread element 14 (hereinafter also referred to as "tread outer peripheral surface 14f") has a curved shape that is convex outward in the tire radial direction in a cross section in the tire width direction, as shown in Figures 4 and 5. The tread outer peripheral surface 14f is the contact surface of the tread element 14. The shape of the tread outer peripheral surface 14f will be described in more detail below, mainly with reference to FIG.

[0025] As mentioned above, Fig. 4 is a cross-sectional view taken along line AA in Fig. 1, i.e., a cross-sectional view in the tire width direction of the non-pneumatic tire 1 in Fig. 1, and Fig. 5 is an enlarged cross-sectional view taken along the line B-B in Fig. 4. In this specification, the term "cross-sectional view in the tire width direction (view)" more specifically refers to a cross-sectional view (view) along both the tire width direction and the tire radial direction. In this embodiment, as mentioned above, the inner cylinder 11, the outer cylinder 12, and the connecting member 13 are integrally formed. Therefore, in the cross section taken along line AA in Figure 1, the boundary line between the outer cylinder 12 and the portion 13c of the connecting member 13 connected to the outer cylinder 12 does not appear, and therefore, in Figures 4 and 5, specific portions are indicated by the symbols "12, 13c."

[0026] In this embodiment, as described above, the curve on the tread outer peripheral surface 14f (hereinafter also referred to as the "tread outer peripheral surface curve"), which is shaped as a curve that convexly extends outward in the tire radial direction when viewed in a cross section in the tire width direction, is a series of multiple arcs each having a different radii of curvature. That is, in this embodiment, as shown in FIG. 5, the tread outer peripheral curved line is a series of a plurality of (three in the illustrated example) circular arcs AC1, AC2, and AC3 having different radii of curvature. More specifically, in this embodiment, the tread outer peripheral surface curved line presents an arc AC1 (hereinafter also referred to as the "center arc AC1") with a single radius of curvature R1 in a center region AR1 including the tire widthwise center CL on the tread outer peripheral surface 14f, an arc AC3 (hereinafter also referred to as the "shoulder arc AC3") with a single radius of curvature R3 in a shoulder region AR3 located on the outermost side in the tire width direction including the tire widthwise outer end (hereinafter also referred to as the "tread edge") TE on the tread outer peripheral surface 14f, and an arc AC2 (hereinafter also referred to as the "intermediate arc AC2") with a single radius of curvature R2 in an intermediate region AR2 located between the center region AR1 and the shoulder region AR3 on the tread outer peripheral surface 14f, and these arcs AC1, AC2, and AC3 are continuously connected (however, R1≠R2, R1≠R3, and R2≠R3). In the illustrated example, the center arc AC1, intermediate arc AC2, and shoulder arc AC3 are smoothly connected to one another, and the centers of curvature of all of these arcs are located radially inward of the tread outer circumferential surface 14f. In this specification, the term "shoulder portion" does not necessarily refer to the same area as the shoulder region AR3, but refers to the entire area near the tread edge TE. In addition, in this specification, the term "center portion" does not necessarily refer to the same area as the center region AR1, but refers to the entire area located closer to the tire widthwise center CL than the shoulder portion. In this specification, the portion formed by a single arc on the tread outer peripheral surface 14f is referred to as an "area," such as the "center region."

[0027] In this embodiment, as shown in Figures 3 to 5, the tread member 14 may have one or more grooves (in this example, two circumferential grooves extending linearly along the tire circumferential direction) 14g in the center region AR1 of the tread outer peripheral surface 14f. However, the tread member 14 does not have to have grooves, and may have grooves in other regions of the tread outer peripheral surface 14f instead of or in addition to the center region AR1, and may also have grooves at the boundary positions of each of the above regions on the tread outer peripheral surface 14f (in other words, at the positions of the connection points of each arc described later). When the tread outer peripheral surface 14f has grooves, in a cross-sectional view in the tire width direction, the extrapolation line of the groove on the tread outer peripheral surface 14f (a line that smoothly connects both opening ends of the groove to the tread outer peripheral surface 14f) is made part of the tread outer peripheral surface curve.

[0028] In this embodiment, as shown in Figures 4 and 5, the tread member 14 and thus the outer circumferential surface 14f of the tread are formed symmetrically on both sides in the tire width direction, with the tire width direction center CL as the axis of symmetry. However, the tread member 14 and thus the outer circumferential surface 14f of the tread may be formed asymmetrically on both sides in the tire width direction.

[0029] In this embodiment, the radius of curvature of the plurality of arcs is smaller for arcs located on the outer circumferential surface 14f of the tread that are on the outer side in the tire width direction. In other words, among the regions on the outer circumferential surface 14f of the tread, the radius of curvature of the arcs in the region located on the outer side in the tire width direction is smaller for adjacent regions than for the radius of curvature of the arcs in the region located on the inner side in the tire width direction. Referring more specifically to Figure 5, in this embodiment, the radius of curvature R2 of the arc AC2 in the intermediate region AR2 is smaller than the radius of curvature R1 of the arc AC1 in the center region AR1. Also, the radius of curvature R3 of the arc AC3 in the shoulder region AR3 is smaller than the radius of curvature R2 of the arc AC2 in the intermediate region AR2.

[0030] The non-pneumatic tire of the present embodiment configured as above has the following advantages. First, in the non-pneumatic tire 1 of this embodiment, the outer peripheral surface 14f of the tread member 14 has a curved shape that is convex outward in the tire radial direction in a cross section in the tire width direction. Therefore, the non-pneumatic tire 14 of this embodiment can appropriately adapt to various road conditions and effectively absorb vibrations transmitted from the ground to the axle, just like a normal pneumatic tire.

[0031] Next, in the non-pneumatic tire 14 of this embodiment, the curve that is convex outward in the tire radial direction is a series of multiple arcs AC1 to AC3 with different radii of curvature, and the radii of curvature R1 to R3 of the multiple arcs AC1 to AC3 are smaller as they are located closer to the outside in the tire width direction on the outer circumferential surface 14f of the tread member 14. In a typical pneumatic tire, the tread has a flexible sidewall portion on the radially inner side, resulting in a large amount of radial deformation. However, in a non-pneumatic tire 1, the outer cylindrical body 12 on the radially inner side of the tread member 14 has very high rigidity and small deformation. Therefore, if the tread outer peripheral surface 14f is formed as a straight line (flat) or as an arc with a large radius of curvature in a cross-sectional view in the tire width direction, the ground contact pressure in the shoulder portion becomes extremely high, particularly when a slip angle or camber angle is applied during driving, causing a wandering phenomenon, deteriorating steering stability, and ultimately reducing maneuverability. This also makes it likely that uneven wear will occur in the shoulder portion of the tread outer peripheral surface 14. In contrast, in this embodiment, the curve in the tread outer peripheral surface 14f is formed of multiple arcs with a smaller radius of curvature toward the outer side in the tire width direction, thereby suppressing a decrease in maneuverability and uneven wear in the shoulder portion due to excessively high ground contact pressure in the shoulder portion. That is, the non-pneumatic tire 1 of the present embodiment can suppress the deterioration of maneuverability and the occurrence of uneven wear in the shoulder portions of the tread members 14. Furthermore, if the curve on the tread outer peripheral surface 14f is formed by a single arc with a single radius of curvature, the ground contact pressure in the center portion of the tread outer peripheral surface 14f will be high, making uneven wear in the center portion more likely to occur. However, according to the non-pneumatic tire 1 of this embodiment, the curve is formed by multiple arcs with different radii of curvature, so uneven wear in the center portion can also be suppressed.

[0032] Hereinafter, with reference mainly to FIG. 5, a preferred embodiment and its effects and advantages of the non-pneumatic tire 1 according to this embodiment will be further described.

[0033] In this embodiment, the radius of curvature R3 of the arc located at the outermost position in the tire width direction, i.e., the shoulder arc AC3 in the shoulder region AR3, is preferably 0.3 times or less the radius of curvature R1 of the arc at the tire width center CL, i.e., the center arc AC1 in the center region AR1. In this case, excessively high ground contact pressure in the shoulder region can be more effectively prevented, thereby further preventing deterioration of maneuverability and uneven wear in the shoulder region of the tread member 14. For similar reasons, the radius of curvature R3 of the shoulder arc AC3 is more preferably 0.1 times or less, and even more preferably 0.05 times or less, of the radius of curvature R1 of the center arc AC1. The radius of curvature R3 can be, for example, 0.01 times or more of the radius of curvature R1. Furthermore, in order to properly and smoothly connect the center arc AC1 and the shoulder arc AC3, it is preferable that the radius of curvature R2 of the intermediate arc AC2 be 0.5 times or more and 0.7 times or less of the radius of curvature R1 of the center arc AC1.

[0034] In this embodiment, as shown in Figure 5, the distance D1 in the tire width direction from the center CL to the center CL of the tread outer surface 14f at the connection point CP1 between the center arc AC1 and the intermediate arc AC2, which is an arc in the intermediate region AR2 adjacent to the center arc AC1 on the outside in the tire width direction, is preferably 2 / 3 or less of the distance in the tire width direction between the center CL and the outer edge TE in the tire width direction on the tread outer surface 14f (in this embodiment, this is equal to 1 / 2 of the tread width TW, which is the distance in the tire width direction between both tread edges TE) D3. In this case, the radius of curvature of the arcs forming the tread outer surface 14f from a position closer to the center CL in the tire width direction becomes smaller, which can more effectively suppress a decrease in maneuverability and the occurrence of uneven wear on the shoulder portion of the tread member 14. For similar reasons, the distance D1 from the tire widthwise center CL to the connection point CP1 between the center arc AC1 and the intermediate arc AC2 is more preferably 3 / 5 or less, and even more preferably 1 / 2 or less, of the tire widthwise distance D3 between the tire widthwise center CL and the tire widthwise outer end TE. The distance D1 can be, for example, 1 / 3 or more of the distance D3. Furthermore, in order for the shoulder arc AC3 to connect appropriately with the intermediate arc AC2, and for the radius of curvature of the outer tread surface 14f to become even smaller from a position close to the tire widthwise center CL, it is preferable that the distance D2 from the tire widthwise center CL to the connection point CP2 between the intermediate arc AC2 and the shoulder arc AC3 is between 1 / 2 and 3 / 4 of the above-mentioned distance D3.

[0035] As explained above, in this embodiment, the curve of the tread outer surface 14f in a cross-sectional view in the tire width direction is a series of three circular arcs AC1 to AC3 with different radii of curvature. In this case, it is possible to effectively suppress the decrease in handling performance and the occurrence of uneven wear on the shoulder portion of the tread member 14 without making the shape of the tread outer surface 14f too complex. However, the multiple arcs with different radii of curvature that form the above curve may be two or four or more arcs. That is, an intermediate arc AC2 does not have to be formed between the center arc AC1 and the shoulder arc AC3 in this embodiment, and two or more intermediate arcs AC2 with different radii of curvature may be formed between the center arc AC1 and the shoulder arc AC3.

[0036] The foregoing describes exemplary embodiments of the present invention, and various modifications can be made without departing from the scope of the claims. [Industrial Applicability]

[0037] The non-pneumatic tire according to the present invention can be mounted on any type of vehicle, and is particularly suitable for mounting on bicycles, motorcycles, automobiles including light vehicles, and steering wheel-type electric wheelchairs.

[0038] The SDGs have been proposed to realize a sustainable society. One embodiment of the present invention is thought to be a technology that can contribute to "No. 12 Responsible Consumption and Production" and "No. 13 Take concrete measures against climate change." [Explanation of symbols]

[0039] 1:Non-pneumatic tires, 11: inner cylinder, 12: outer cylinder, 13: connecting member; 13a, 13b, 13c: parts of the connecting member; 14: tread member, 14f: outer peripheral surface of the tread member (tread outer peripheral surface), 14g: groove, 14s: side of tread material, 2: Rim, 2a: Bolt through hole, 3: Tire and rim assembly, AC1: Arc (center arc), AC2: Arc (intermediate arc), AC3: Arc (shoulder arc), AR1: Center area, AR2: Intermediate area, AR3: Shoulder region, CD: Circumferential direction of the tire, CL: Center in the width direction of the tire. CP1, CP2: connection points, D1, D2, D3: distances, O: central axis. R1, R2, R3: radius of curvature, RD: tire radial direction, TE: The outer edge in the tire width direction on the outer circumference of the tread member (tread edge), WD: Tire width direction

Claims

1. A non-pneumatic tire comprising: an inner cylindrical body; an outer cylindrical body surrounding the inner cylindrical body from the outside in the tire radial direction; an elastically deformable connecting member connecting the inner cylindrical body and the outer cylindrical body to each other; and a tread member provided on an outer peripheral surface of the outer cylindrical body, an outer peripheral surface of the tread member having a curved shape that is convex outward in the tire radial direction in a cross-sectional view in the tire width direction, the curve is a series of multiple arcs each having a different radius of curvature, A non-pneumatic tire, wherein the radii of curvature of the plurality of arcs are smaller toward the outer sides in the tire width direction on the outer circumferential surface of the tread element.

2. 2. The non-pneumatic tire according to claim 1, wherein the radius of curvature of the shoulder arc, which is the arc located at the outermost side in the tire width direction, is 0.3 times or less the radius of curvature of the center arc, which is the arc at the center in the tire width direction.

3. 3. The non-pneumatic tire according to claim 1, wherein a distance in the tire width direction from the tire width center to a connection point between a center arc, which is the arc at the tire width center, and an intermediate arc, which is the arc adjacent to the center arc on the tire width direction outer side, is two-thirds or less of a distance in the tire width direction between the tire width center and an outer end in the tire width direction on an outer peripheral surface of the tread element.

4. The non-pneumatic tire according to claim 1 , wherein the curved line is a series of three arcs each having a different radius of curvature.

Images