Non-pneumatic tires

Abstract

To provide a non-pneumatic tire configured to be able to reduce vehicle exterior noise and improve riding comfort while securing load support force.SOLUTION: A non-pneumatic tire 1 comprises an outer annular part 2 having a tread 5 at an outer periphery, an inner annular part 3 provided at inside the outer annular part 2, and connection parts 4 provided along a tire circumferential direction D to connect the outer annular part 2 to the inner annular part 3. The connection parts 4 are provided so that when loads of 2.45 kN or more are applied to the non-pneumatic tire 1, the tread 5 deflects and deforms in the tire circumferential direction D in a grounding area C which grounds a road surface R to make the adjacent connection parts 4 and 4 contact each other and support each other.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] In recent years, non-pneumatic tires that are free from problems such as punctures have become known (see, for example, Patent Document 1, etc.). In general, non-pneumatic tires have a structure in which an outer annular portion and an inner annular portion provided inside the outer annular portion are connected by connecting portions arranged along the tire circumferential direction. When a non-pneumatic tire receives a load from a vehicle, a compressive force acts on the connecting portions arranged in the contact area, causing the tire to flex and deform. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-218132 A Summary of the Invention [Problem to be solved by the invention]

[0004] Since the connecting portions of conventional non-pneumatic tires are arranged at intervals in the tire circumferential direction, the difference in ground contact pressure between the portions with and without connecting portions in the contact area becomes large. Therefore, conventional non-pneumatic tires have a problem in that the difference in ground contact pressure in the contact area causes a large external noise during driving.

[0005] In addition, the connecting parts of conventional non-pneumatic tires are made highly rigid to ensure durability sufficient to support the load from the vehicle, but in this case, the ride comfort of the vehicle deteriorates. The ride comfort can be improved by making the connecting parts more flexible, but the tendency of the connecting parts to bend and deform easily results in a contradictory problem of a decrease in the load support capacity.

[0006] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a non-pneumatic tire that can reduce external noise and improve ride comfort while ensuring load supporting capacity. [Means for solving the problem]

[0007] The present invention provides a non-pneumatic tire comprising an outer annular portion having a tread on its outer circumference, an inner annular portion provided inside the outer annular portion, and a connecting portion that connects the outer annular portion and the inner annular portion and is provided along the tire circumferential direction, wherein the connecting portion is configured such that when a load of 2.45 kN or more is applied to the non-pneumatic tire, adjacent connecting portions come into contact with and support each other by flexing and deforming in the tire circumferential direction in the contact area where the tread comes into contact with the road surface. Effect of the Invention

[0008] According to the present invention, it is possible to provide a non-pneumatic tire that can reduce external vehicle noise and improve ride comfort while ensuring load bearing capacity. [Brief description of the drawings]

[0009] [Figure 1] 1 is a front view showing an embodiment of a non-pneumatic tire of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Diagram 3] FIG. 2 is a front view showing the contact area of ​​a non-pneumatic tire when a load from a vehicle is applied. [Figure 4] 4 is an enlarged view showing two adjacent connecting portions in FIG. 3. FIG. [Diagram 5] FIG. 3 is a cross-sectional view taken along line BB in FIG. [Figure 6] FIG. 2 is a front view showing a portion of another embodiment of a non-pneumatic tire of the present invention. [Figure 7] FIG. 11 is a front view showing a contact area of ​​a non-pneumatic tire according to another embodiment of the present invention, with a load from a vehicle being applied thereto. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a front view showing one embodiment of a non-pneumatic tire of the present invention. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. The non-pneumatic tire 1 includes an outer annular portion 2, an inner annular portion 3 provided concentrically inside the outer annular portion 2, and a plurality of connecting portions 4 that connect the outer annular portion 2 and the inner annular portion 3 and are each provided independently along the tire circumferential direction D. A tread 5 is provided on the outer periphery of the outer annular portion 2. The tread 5 is provided with a tread pattern similar to that of a conventional pneumatic tire.

[0011] First, the outer annular portion 2 and the inner annular portion 3 will be described. In the following, the thickness of the outer annular portion 2 and the inner annular portion 3 refers to the plate thickness in the direction along the tire radial direction X shown in Figures 1 and 2. The width of the outer annular portion 2 and the inner annular portion 3 refers to the width in the direction along the tire width direction Y shown in Figure 2.

[0012] From the viewpoint of improving uniformity, the outer annular portion 2 has a constant thickness in the circumferential direction and the width direction. The thickness of the outer annular portion 2 is not particularly limited, but from the viewpoint of achieving weight reduction and improved durability while sufficiently transmitting the force from the connecting portion 4, it is preferably 2% to 7% and more preferably 2% to 5% of the tire cross-sectional height H shown in Fig. 2.

[0013] The inner diameter of the outer annular portion 2 is appropriately determined depending on the application, etc. For example, when assuming a replacement for a general pneumatic tire, the inner diameter of the outer annular portion 2 can be set to 420 mm or more and 750 mm or less.

[0014] The width of the outer annular portion 2 is appropriately determined depending on the application, etc. For example, when assuming a replacement for a general pneumatic tire, the width of the outer annular portion 2 can be set to 100 mm or more and 300 mm or less.

[0015] The inner annular portion 3 has a constant thickness in the circumferential and width directions from the viewpoint of improving uniformity. Although not shown, the inner peripheral surface of the inner annular portion 3 may be provided with irregularities or the like for maintaining fit when attached to an axle or a rim. The thickness of the inner annular portion 3 is not particularly limited, but from the viewpoint of achieving weight reduction and improved durability while sufficiently transmitting force to the connecting portion 4, it is preferably 2% to 7% of the tire cross-sectional height H shown in FIG. 2, and more preferably 3% to 6%.

[0016] The inner diameter of the inner annular portion 3 is appropriately determined according to the dimensions of the rim and axle on which the non-pneumatic tire 1 is mounted. For example, when assuming a replacement for a general pneumatic tire, the inner diameter of the inner annular portion 3 can be set to 250 mm or more and 500 mm or less.

[0017] The width of the inner annular portion 3 is determined appropriately depending on the application, the length of the axle, etc. For example, when assuming a replacement for a general pneumatic tire, the width of the inner annular portion 3 can be set to 100 mm or more and 300 mm or less.

[0018] The connecting portions 4 are members that function as spokes that connect the outer annular portion 2 and the inner annular portion 3 to maintain a constant interval in the non-pneumatic tire 1. The multiple connecting portions 4 are arranged independently at constant intervals along the tire circumferential direction D, and extend linearly in radial directions along the tire radial direction X when the non-pneumatic tire 1 in an unloaded state is viewed from the front in a direction along the tire rotation axis, as shown in Fig. 1 .

[0019] The connecting portion 4 is made of an elastic material. The elastic material refers to a material having a tensile modulus of 100 MPa or less, calculated from the tensile stress at 10% elongation in a tensile test performed in accordance with JIS K7321. Specifically, from the viewpoint of imparting appropriate rigidity while ensuring sufficient durability, the tensile modulus is preferably 5 MPa or more and 100 MPa or less, and more preferably 7 MPa or more and 50 MPa or less.

[0020] The elastic material used as the base material of the connecting portion 4 may be a thermoplastic elastomer, a crosslinked rubber, or other resin.

[0021] Examples of the thermoplastic elastomer include polyester elastomers, polyolefin elastomers, polyamide elastomers, polystyrene elastomers, polyvinyl chloride elastomers, and polyurethane elastomers.

[0022] Either natural rubber or synthetic rubber can be used as the rubber material constituting the crosslinked rubber. Examples of synthetic rubber 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 necessary.

[0023] Other resins include thermoplastic resins and thermosetting resins. Thermoplastic resins include polyethylene resins, polystyrene resins, polyvinyl chloride resins, etc. Thermosetting resins include epoxy resins, phenolic resins, polyurethane resins, silicone resins, polyimide resins, melamine resins, etc.

[0024] Of the above elastic materials, polyurethane resin is preferably used for the connecting portion 4 from the viewpoints of moldability, processability, and cost. A foamed material can also be used as the elastic material. That is, foamed materials of the above thermoplastic elastomers, crosslinked rubbers, and other resins can be used. In addition, when the outer annular portion 2 and the inner annular portion 3 are made of resin, the connecting portion 4 may be integrally formed with the outer annular portion 2 and the inner annular portion 3 using the same resin material.

[0025] In the connecting portion 4 of this embodiment, the first connecting portion 41 and the second connecting portion 42 are alternately arranged along the tire circumferential direction D. As shown in Fig. 2, the first connecting portion 41 extends from one side Y1 in the tire width direction Y of the outer annular portion 2 toward the other side Y2 in the tire width direction Y of the inner annular portion 3. Meanwhile, the second connecting portion 42 extends from the other side Y2 in the tire width direction Y of the outer annular portion 2 toward one side Y1 in the tire width direction Y of the inner annular portion 3. That is, the first connecting portion 41 and the second connecting portion 42 adjacent to each other in the tire circumferential direction D are arranged in a substantially X-shape when viewed from the tire circumferential direction D.

[0026] 2, the first connecting portion 41 and the second connecting portion 42 have the same shape and are symmetrical with respect to the tire equatorial plane S when viewed from the tire circumferential direction D. Therefore, the specific shape of the connecting portion 4 will be described using the first connecting portion 41. The tire equatorial plane S is a plane that is perpendicular to the tire rotation axis (tire meridian) and is located at the center in the tire width direction Y.

[0027] The connecting portion 4 is formed in a long plate shape extending obliquely from the outer annular portion 2 to the inner annular portion 3. As shown in FIG. 2 and FIG. 5, the connecting portion 4 has a plate thickness t smaller than the plate width w, and the plate thickness direction PT faces the tire circumferential direction D. That is, the connecting portion 4 is formed in a plate shape extending in the tire radial direction X and the tire width direction Y. The plate thickness t of the connecting portion 4 is the thickness of the connecting portion 4 along the tire circumferential direction D. The plate width w of the connecting portion 4 is the width in a direction perpendicular to the extension direction of the connecting portion 4 when the connecting portion 4 is viewed from the direction along the tire circumferential direction D. Since the connecting portion 4 is in such a long plate shape, even if the plate thickness t is thin, the durability of the connecting portion 4 when the plate thickness t is thin can be improved by setting the plate width w wide. Furthermore, by increasing the number of the first connecting portions 41 and the second connecting portions 42 while reducing the plate thickness t, the gap between the connecting portions 4, 4 adjacent to each other in the tire circumferential direction D can be reduced while maintaining the rigidity of the entire tire. This reduces dispersion of ground contact pressure when the tire is rolling.

[0028] 2, the connecting portion 4 has a shape in which a connection portion 401 with the outer annular portion 2 and a connection portion 402 with the inner annular portion 3 each gently widen along the tire width direction Y. The connecting portion 4 has a substantially constant plate width w between each of the connection portions 401, 402. The connection portion 401 with the outer annular portion 2 of the first connecting portion 41 is provided over half the area of ​​the outer annular portion 2 in the tire width direction.

[0029] That is, one side Y1 of the connection portion 401 of the first coupling portion 41 extends to an end 2a of the one side Y1 of the outer annular portion 2. The other side Y2 of the connection portion 401 of the first coupling portion 41 extends to a tire equatorial plane S located in the center of the outer annular portion 2 in the tire width direction. The other side Y2 of the connection portion 401 of the first coupling portion 41 extends to an end 3b of the other side Y2 of the inner annular portion 3. One side Y1 of the connection portion 402 of the first coupling portion 41 extends to the tire equatorial plane S located in the center of the inner annular portion 3 in the tire width direction.

[0030] Similarly, the other side Y2 of the connection portion 401 of the second coupling portion 42 extends to an end 2b of the other side Y2 of the outer annular portion 2. One side Y1 of the connection portion 401 of the second coupling portion 42 extends to a tire equatorial plane S located in the center of the outer annular portion 2 in the tire width direction. One side Y1 of the connection portion 402 of the second coupling portion 42 extends to an end 3a of the one side Y1 of the inner annular portion 3. The other side Y2 of the connection portion 402 of the second coupling portion 42 extends to a tire equatorial plane S located in the center of the inner annular portion 3 in the tire width direction.

[0031] The plate thickness t of the connecting portion 4 is preferably 1 mm or more and 30 mm or less, and more preferably 5 mm or more and 25 mm or less, from the viewpoint of easily bending and deforming when a load is applied as described below, while sufficiently transmitting the force from the outer annular portion 2 and the inner annular portion 3. The plate thickness t of the connecting portion 4 does not have to be the same from the outer annular portion 2 to the inner annular portion 3. For example, the plate thickness t of the connecting portion 4 may be formed so that the plate thickness in the center is smaller than the plate thickness on the connection side with the outer annular portion 2 and the inner annular portion 3, in order to easily bend and deform when a load is applied.

[0032] The plate width w of the connecting portion 4 is preferably 5 mm or more and 25 mm or less, and more preferably 10 mm or more and 20 mm or less, from the viewpoint of reducing weight and improving durability while sufficiently transmitting the force from the outer annular portion 2 and the inner annular portion 3. Moreover, the plate width w is preferably 110% or more of the plate thickness t, and more preferably 115% or more, from the viewpoint of reducing ground pressure dispersion while improving durability.

[0033] The pitch p between the first connecting portion 41 and the second connecting portion 42 adjacent in the tire circumferential direction D is preferably constant and small in the tire circumferential direction D. As described later, this pitch p is set narrow so that the first connecting portion 41 and the second connecting portion 42 adjacent in the tire circumferential direction D can contact each other when they are flexed and deformed by the load from the vehicle at the contact area C. This makes it possible to reduce external noise when the non-pneumatic tire 1 rolls. Specifically, the pitch p is preferably 1 mm or more and 10 mm or less, and more preferably 1 mm or more and 5 mm or less. If the pitch p is larger than 10 mm, the ground contact pressure is likely to become non-uniform in the tire circumferential direction D, which may cause external noise.

[0034] The number of connecting parts 4 provided in the non-pneumatic tire 1 is preferably 80 to 300, and more preferably 100 to 200, from the viewpoints of allowing adjacent connecting parts 4, 4 to come into contact with each other when the tire is flexibly deformed, and of achieving weight reduction, improved power transmission, and improved durability while adequately supporting the load from the vehicle. Fig. 1 shows an example in which 50 first connecting parts 41 and 50 second connecting parts 42 are provided.

[0035] Fig. 3 is a front view showing the contact area of ​​the non-pneumatic tire 1 with a load from a vehicle applied thereto. Fig. 4 is an enlarged view showing two adjacent connecting portions in Fig. 3. As shown in Figs. 3 and 4, each connecting portion 4 of the non-pneumatic tire 1 is provided so as to be easily flexibly deformed by the load from the vehicle.

[0036] Specifically, when a load of 2.45 kN or more is applied to the non-pneumatic tire 1 in a contact area C where the tread 5 comes into contact with the road surface R, at least one of the connecting parts 4A, 4A arranged near both ends in the tire circumferential direction D of the contact area C is largely bent and deformed into an L-shape toward the outside of the contact area C along the tire circumferential direction D. That is, the connecting part 4 is bent and deformed in opposite directions along the tire circumferential direction D, with the approximate center of the contact area C along the tire circumferential direction D as the boundary. As a result, the connecting parts 4A, 4A bent and deformed into an L-shape come into contact with the connecting parts 4B, 4B adjacent to each other in the protruding direction of the L-shape at contact parts CT.

[0037] As shown in Fig. 3 and Fig. 4, in the non-pneumatic tire 1 of this embodiment, at least one each of the connecting parts 4A, 4A arranged near both ends in the tire circumferential direction D of the contact area C is largely deformed into a dogleg shape toward the outside of the contact area C along the tire circumferential direction D. The direction of deformation of the connecting parts 4A, 4A is a direction in which each becomes convex toward the outside of the contact area C along the tire circumferential direction D. As shown in Fig. 4, the surface 4A1 on the convex side of the dogleg shape of the connecting part 4A that has been deformed the most is in contact with the surface 4B1 on the concave side of the connecting part 4B that is adjacent to the convex side and is slightly deformed into a dogleg shape. The contacting connecting parts 4, 4 support each other, thereby suppressing excessive deformation and integrally supporting the load from the vehicle.

[0038] The load of 2.45 kN or more applied to the non-pneumatic tire 1 is a load that acts vertically downward from the inner annular portion 3 to the outer annular portion 2 of the non-pneumatic tire 1 when the non-pneumatic tire 1 is mounted on a vehicle and in contact with the road surface R. This load is measured by mounting an appropriate wheel on the non-pneumatic tire 1 and applying a static load in the vertical downward direction centered on the wheel.

[0039] In addition, the contact area C is an area along the tire circumferential direction D when the non-pneumatic tire 1 is mounted on a vehicle and in contact with a road surface R and the tread 5 is in pressure contact with the road surface R due to the weight of the vehicle. Note that Fig. 3 and Fig. 4 show a case where the non-pneumatic tire 1 rolls in one direction D1 along the tire circumferential direction D.

[0040] In this way, the connecting parts 4 of the non-pneumatic tire 1 are provided in the contact area C where the tread 5 contacts the road surface R so that at least two adjacent connecting parts 4,4 come into contact with each other and support each other by being flexibly deformed in the tire circumferential direction D due to the load from the vehicle. Therefore, the load support capacity of the connecting parts 4 in the contact area C is improved. In this way, the connecting parts 4 support the load by being in contact with the adjacent connecting parts 4, so the connecting parts 4 can be formed to be easily flexibly deformed. This improves the cushioning properties of the non-pneumatic tire 1, improving the ride comfort. Furthermore, the adjacent connecting parts 4,4 are close enough to each other that they can come into contact when flexibly deformed, so the pressure difference in the contact area C due to the presence or absence of the connecting parts 4 is small. Therefore, the noise outside the vehicle during driving is reduced.

[0041] As shown in Figs. 2 to 6, each of the connecting parts 4 preferably has a wear-resistant layer 6 having higher wear resistance than the connecting part 4 (the base material of the connecting part 4) at least at the contact part with the adjacent connecting part 4. In the connecting part 4 of the non-pneumatic tire 1 of this embodiment, the first connecting part 41 and the second connecting part 42 arranged to intersect in a substantially X-shape as viewed from the tire circumferential direction D are alternately arranged along the tire circumferential direction D, so that the adjacent first connecting part 41 and the second connecting part 42 contact each other only at the center parts in the extension direction of the first connecting part 41 and the second connecting part 42 during flexural deformation. Therefore, the wear-resistant layer 6 may be provided only at the center parts where the first connecting part 41 and the second connecting part 42 intersect each other as viewed from the tire circumferential direction D, as shown in Fig. 2.

[0042] In this way, each of the connecting parts 4 has the wear-resistant layer 6 at least at the contact area with the adjacent connecting parts 4, thereby improving the wear resistance when the adjacent connecting parts 4, 4 come into contact with each other, and improving the durability of the connecting parts 4. The wear resistance is evaluated based on the value obtained by performing an abrasion test in accordance with JIS K6264-2.

[0043] The wear-resistant layer 6 is formed of a resin or rubber having higher wear resistance than the connecting portion 4 (base material of the connecting portion 4). Specifically, the wear-resistant layer 6 can be formed of a material having a lower friction coefficient than the connecting portion 4 (base material of the connecting portion 4). The wear-resistant layer 6 may also be formed of a material having a smaller surface roughness than the connecting portion 4 (base material of the connecting portion 4). Furthermore, the wear-resistant layer 6 may also be formed of a material having a higher hardness than the connecting portion 4 (base material of the connecting portion 4). The wear-resistant layer 6 may also be a material having two or more of the above-mentioned functions of friction coefficient, surface roughness, and hardness.

[0044] The wear-resistant layer 6, which has a lower coefficient of friction than the connecting portion 4 (base material of the connecting portion 4), can be formed, for example, from a fluororesin. The wear-resistant layer 6 made of a fluororesin may be formed by coating the outer surface of the connecting portion 4 with a fluororesin. The wear-resistant layer 6, which has a smaller surface roughness than the connecting portion 4, may be formed from an appropriate resin or rubber that is different from the base material of the connecting portion 4 and has a smaller surface roughness than the base material of the connecting portion 4, or may be formed by using the same material as the base material of the connecting portion 4 and reducing only the surface roughness by, for example, a method such as polishing the surface. The wear-resistant layer 6, which has a higher hardness than the connecting portion 4 (base material of the connecting portion 4), may be formed from a thermosetting resin that is harder than the base material thermosetting resin when the base material of the connecting portion 4 is a thermosetting resin, or may be formed from a thermoplastic elastomer. Examples of the thermoplastic elastomer include polyester-based, urethane-based, amide-based, olefin-based, and styrene-based materials.

[0045] As shown in FIG. 5, the wear-resistant layer 6 is provided at least on both sides 4a, 4a of the first connecting portion 41 and the second connecting portion 42 facing the tire circumferential direction D. However, as in the connecting portion 4 of this embodiment, when the first connecting portion 41 and the second connecting portion 42 are arranged to intersect in a substantially X-shape as viewed from the tire circumferential direction D, when the first connecting portion 41 and the second connecting portion 42 are flexed and deformed and come into contact with each other, the respective corners 4b, 4b may come into contact with each other. Since the contact between the corners 4b, 4b is more likely to wear out than the contact between the surfaces, it is preferable that the wear-resistant layer 6 is provided from both sides 4a, 4a of the connecting portion 4, which is the contact portion between the adjacent first connecting portion 41 and the second connecting portion 42, to the outer side surface 4c and the inner side surface 4d facing the tire width direction Y, via the corners 4b, 4b. As a result, the corner 4b of the connecting portion 4 is protected by the wear-resistant layer 6 from the outer side surface 4c to the inner side surface 4d, so that wear of the corner 4b is suppressed and the durability of the connecting portion 4 is further improved.

[0046] In the connecting portion 4, the outer side surface 4c facing in the tire width direction Y is the surface that faces toward the outer side of the vehicle when the non-pneumatic tire 1 is mounted on a vehicle, and the inner side surface 4d is the opposite side that faces toward the inner side of the vehicle. In the non-pneumatic tire 1 of this embodiment, the Y1 direction side in the tire width direction Y is defined as the outer side, and the Y2 direction side is defined as the inner side.

[0047] The non-pneumatic tire 1 of the present embodiment provides the following advantages.

[0048] (1) The non-pneumatic tire according to the present embodiment is a non-pneumatic tire 1 including an outer annular portion 2 having a tread 5 on its outer periphery, an inner annular portion 3 concentrically provided inside the outer annular portion 2, and a plurality of connecting portions 4 that connect the outer annular portion 2 and the inner annular portion 3 and are provided independently along the tire circumferential direction D. The connecting portions 4 are provided so that when a load of 2.45 kN or more is applied to the non-pneumatic tire 1, adjacent connecting portions 4, 4 come into contact with each other and support each other by being flexibly deformed in the tire circumferential direction D at a contact area C where the tread 5 comes into contact with the road surface R. By supporting each other, the contacting connecting portions 4, 4 suppress excessive flexural deformation and integrally support the load from the vehicle. Therefore, the load support capacity of the connecting portions 4 at the contact area C is improved. Since the connecting portions 4 themselves can be formed to be easily flexibly deformed, the cushioning properties of the non-pneumatic tire 1 are improved and the ride comfort is improved. Furthermore, since the adjacent connecting parts 4, 4 are close enough to each other that they can come into contact when they are flexed and deformed by a load of 2.45 kN or more, the pressure difference between the presence and absence of the connecting parts 4 at the contact area C is small. Therefore, the external noise during driving is reduced.

[0049] (2) Each of the multiple connecting portions 4 of the non-pneumatic tire 1 according to the present embodiment has an abrasion-resistant layer 6 at a contact portion with the adjacent connecting portions 4, 4. This improves the abrasion resistance when the adjacent connecting portions 4, 4 come into contact with each other, and improves the durability of the connecting portions 4.

[0050] (3) The wear-resistant layer 6 of the non-pneumatic tire 1 according to the present embodiment may be made of a material having a lower friction coefficient than the connecting portions 4. This improves the wear resistance when the adjacent connecting portions 4, 4 come into contact with each other, and improves the durability of the connecting portions 4.

[0051] (4) The wear-resistant layer 6 of the non-pneumatic tire 1 according to the present embodiment may be made of a material having a smaller surface roughness than the connecting portions 4. This improves the wear resistance when the adjacent connecting portions 4, 4 come into contact with each other, and improves the durability of the connecting portions 4.

[0052] (5) The wear-resistant layer 6 of the non-pneumatic tire 1 according to the present embodiment may be made of a material having a higher hardness than the connecting portions 4. This improves the wear resistance when the adjacent connecting portions 4, 4 come into contact with each other, and improves the durability of the connecting portions 4.

[0053] (6) The wear-resistant layer 6 of the non-pneumatic tire 1 according to this embodiment is provided from the surface 4a facing in the tire circumferential direction D and contacting the adjacent connecting portions 4, 4 to the outer side surface 4c and the inner side surface 4d facing in the tire width direction Y. As a result, the corners 4b of the connecting portions 4 that are easily worn upon contact are protected from the outer side surface 4c and the inner side surface 4d by the wear-resistant layer 6, thereby suppressing wear of the corners 4b and further improving the durability of the connecting portions 4.

[0054] (7) The multiple connecting parts 4 of the non-pneumatic tire 1 according to this embodiment are configured by alternately arranging the long plate-like first connecting parts 41 extending from one side Y1 of the outer annular part 2 in the tire width direction Y toward the other side Y2 of the inner annular part 3 in the tire width direction Y, and the long plate-like second connecting parts 42 extending from the other side Y2 of the outer annular part 2 in the tire width direction Y toward the one side Y1 of the inner annular part 3 in the tire width direction Y, along the tire circumferential direction. As a result, even if the plate thickness t of the connecting parts 4 is thin, the desired rigidity of the connecting parts 4 can be ensured by setting the plate width w wide, so that even if the connecting parts 4 are thin and easily deformed, the durability of the connecting parts 4 is improved, and the ride comfort of the non-pneumatic tire 1 is further improved. Moreover, the alternating arrangement of the first connecting parts 41 and the second connecting parts 42 can further reduce the dispersion of ground pressure during tire rotation.

[0055] The connecting portion 4 of the non-pneumatic tire 1 shown in the above embodiment is configured by a first connecting portion 41 and a second connecting portion 42 arranged to intersect in a substantially X-shape when viewed from the tire circumferential direction D, but is not limited to this. All the connecting portions 4 may be formed in a strip shape extending from the outer annular portion 2 to the inner annular portion 3. The strip-shaped connecting portion 4 may have the same width from the outer annular portion 2 to the inner annular portion 3, or may have different widths on the outer annular portion 2 side and the inner annular portion 3 side. In addition, the plate thickness t of each connecting portion 4 is not limited to the same thickness from the outer annular portion 2 to the inner annular portion 3, and may be different between the outer annular portion 2 side and the inner annular portion 3 side.

[0056] The connecting portion 4 of the non-pneumatic tire 1 shown in the above embodiment extends linearly in the radial direction along the tire radial direction X in an unloaded state, as shown in FIG. 1. However, the connecting portion 4 is not limited to extending linearly in this manner. For example, as in the non-pneumatic tire 1A shown in FIG. 6, when the non-pneumatic tire 1A in an unloaded state is viewed from the front in a direction along the tire rotation axis, the connecting portion 4 may be bent in a dogleg shape that is convex in one direction along the tire circumferential direction D. In this non-pneumatic tire 1A as well, when a load of 2.45 kN or more is applied, as shown in FIG. 7, the adjacent connecting portions 4, 4 are provided to come into contact with each other and support each other. [Explanation of symbols]

[0057] 1. Non-pneumatic tires 2 Outer annular part 3 Inner annulus 4 Connecting part 4a side 4b Corner 4c Outer side 4d medial side 41 1st connection part 42 2nd connection part 5 Tread 6. Wear-resistant layer C. Contact area D Tire Circumferential Direction R Road surface Y Tire width direction Y1 one side Y2 other side

Claims

1. an outer annular portion having a tread on an outer periphery; an inner annular portion provided inside the outer annular portion; a connecting portion that connects the outer annular portion and the inner annular portion and is provided along a tire circumferential direction, the connecting portion is configured by a first connecting portion extending from one side of the outer annular portion in the tire width direction toward the other side of the inner annular portion in the tire width direction, and a second connecting portion extending from the other side of the outer annular portion in the tire width direction toward the one side of the inner annular portion in the tire width direction, the first connecting portions and the second connecting portions are alternately arranged along the tire circumferential direction, the connecting portions are configured so that, when a load of 2.45 kN or more is applied to the non-pneumatic tire, adjacent connecting portions come into contact with and support each other by flexing and deforming in the tire circumferential direction in a contact area where the tread contacts the road surface.

2. The non-pneumatic tire according to claim 1 , wherein the connecting portions have a wear-resistant layer at contact portions with adjacent connecting portions.

3. The non-pneumatic tire according to claim 2 , wherein the wear-resistant layer is made of a material having a lower coefficient of friction than the connecting portions.

4. The non-pneumatic tire according to claim 2 or 3, wherein the wear-resistant layer is made of a material having a surface roughness smaller than that of the connecting portion.

5. The non-pneumatic tire according to any one of claims 2 to 4, wherein the wear-resistant layer is made of a material having a higher hardness than the connecting portion.

6. The non-pneumatic tire according to any one of claims 2 to 5, wherein the wear-resistant layer is provided from a surface facing in the tire circumferential direction that contacts adjacent connecting portions to an outer side surface and an inner side surface facing in the tire width direction.

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