Airless tires

Abstract

The present invention provides a non-pneumatic tire, which can ensure the distance between adjacent connecting parts on the inner annular part side, and can improve the strength of the connection part between the inner annular part and the connecting part, so as to improve the durability of the connecting part. The non-pneumatic tire comprises: an outer annular part, an inner annular part and a plurality of connecting parts. The plurality of connecting parts are formed by arranging the first connecting part and the second connecting part alternately along the tire circumferential direction, the first connecting part is arranged to extend from one side of the tire width direction of the outer annular part toward the other side of the tire width direction of the inner annular part, and the second connecting part is arranged to extend from the other side of the tire width direction of the outer annular part toward one side of the tire width direction of the inner annular part. In terms of the thickness of each of the plurality of connecting parts along the tire circumferential direction, the inner annular part side is smaller than the outer annular part side, and in terms of the width of each of the plurality of connecting parts along the tire width direction, the inner annular part side is larger than the outer annular part side.

Description

Technical Field

[0001] The present invention relates to a pneumatic-free tire. Background Art

[0002] In recent years, a pneumatic tire that does not cause problems such as tire blowouts has become well known (for example, see Patent Document 1, etc.). Generally, a pneumatic tire has a structure in which an outer annular portion and an inner annular portion are connected by a plurality of plate-shaped connecting portions arranged in the circumferential direction of the tire, wherein the inner annular portion is arranged concentrically on the inner side of the outer annular portion. When a pneumatic tire is subjected to a load from a vehicle, a compressive force acts on the connecting portion arranged in the ground contact area, causing flexural deformation.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-218132 Summary of the invention

[0006] In a pneumatic-free tire, the distance between adjacent connecting parts in the tire circumferential direction is larger on the outer annular part side and smaller on the inner annular part side because of the circumference difference between the outer annular part and the inner annular part. Thus, as the number of connecting parts increases, it is difficult to ensure the distance between adjacent connecting parts. On the other hand, in order to ensure the distance between adjacent connecting parts, when the thickness of the connecting part along the tire circumferential direction is made smaller on the inner annular part side than on the outer annular part side, the strength of the connecting part will be different between the connecting part connected to the outer annular part and the connecting part connected to the inner annular part, thereby reducing the durability of the connecting part, and when repeated stress is applied to the connecting part during tire rolling, the connecting part may break. Therefore, the previous pneumatic-free tire has left the following problem: it is necessary to ensure the distance between adjacent connecting parts on the inner annular part side, and at the same time, it is possible to improve the strength of the connecting part between the inner annular part and the connecting part, so as to improve the durability of the connecting part.

[0007] The present invention is completed in view of the above-mentioned problems, and its purpose is to provide a pneumatic tire as follows: the distance between adjacent connecting parts can be ensured on the inner annular part side, and the strength of the connection part between the inner annular part and the connecting part can be improved, thereby improving the durability of the connecting part.

[0008] The pneumatic tire of the present invention comprises: an outer annular portion having a tread portion on its outer circumference; an inner annular portion provided on the inner side of the outer annular portion; and a plurality of connecting portions connecting the outer annular portion and the inner annular portion and provided along the tire circumferential direction, the plurality of connecting portions being constituted by arranging first connecting portions and second connecting portions alternately along the tire circumferential direction, the first connecting portion being provided to extend 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, the second connecting portion being provided to extend from the other side of the outer annular portion in the tire width direction toward one side of the inner annular portion in the tire width direction, the thickness of each of the plurality of connecting portions along the tire circumferential direction being smaller on the inner annular portion side than on the outer annular portion side, and the width of each of the plurality of connecting portions along the tire width direction being larger on the inner annular portion side than on the outer annular portion side.

[0009] According to the present invention, a pneumatic-free tire can be provided in which the distance between adjacent connecting portions can be ensured on the inner annular portion side, and the strength of the connection portion between the inner annular portion and the connecting portion can be increased, thereby improving the durability of the connecting portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a front view showing a pneumatic-free tire according to one embodiment of the present invention.

[0011] Figure 2 It is along Figure 1 Cross-sectional view along line A-A in FIG.

[0012] Figure 3 It is along Figure 2 Cross-sectional view of line B-B in .

[0013] Figure 4 It is a diagram for explaining the thickness of the connecting portion along the tire circumferential direction.

[0014] Figure 5 It is a cross-sectional view showing a connection portion of a pneumatic-free tire according to another embodiment of the present invention.

[0015] Figure 6 It is a cross-sectional view showing a connection portion of a pneumatic-free tire according to still another embodiment of the present invention.

[0016] Description of Reference Numerals

[0017] 1…airless tire; 2…outer annular portion; 3…inner annular portion; 4…connecting portion; 41…first connecting portion; 42…second connecting portion; 5…tread portion; D…tire circumferential direction; T…plate thickness; Tt…plate thickness on the outer annular portion side; Tr…plate thickness on the inner annular portion side; W…plate width; Wt…plate width on the outer annular portion side; Wr…plate width on the inner annular portion side; X…tire radial direction; Y…tire width direction; Y1…one side; Y2…the other side. DETAILED DESCRIPTION

[0018] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 It is a front view showing a pneumatic-free tire according to one embodiment of the present invention. Figure 2 It is along Figure 1 Cross-sectional view along line A-A in FIG. Figure 3 It is along Figure 2 The pneumatic tire 1 is a cross-sectional view taken along the line BB in FIG. The pneumatic tire 1 includes an outer annular portion 2, an inner annular portion 3 provided concentrically on the inner side of the outer annular portion 2, and a plurality of connecting portions 4 connecting the outer annular portion 2 and the inner annular portion 3 and provided independently along the tire circumferential direction D. A tread portion 5 is provided on the outer periphery of the outer annular portion 2. The tread portion 5 has a tread pattern similar to that of a conventional pneumatic tire.

[0019] First, the outer annular portion 2 and the inner annular portion 3 are described. In the following description, the thickness of the outer annular portion 2 and the inner annular portion 3 refers to: Figure 1 as well as Figure 2 The thickness of the plate in the tire radial direction X is shown. The width of the outer annular portion 2 and the inner annular portion 3 is: Figure 2 The width of the tire is shown in the direction of the tire width direction Y.

[0020] 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 being able to sufficiently transmit the force from the connecting portion 4 and achieving weight reduction and improved durability, it is preferably Figure 2 The tire cross-sectional height H shown is 2% or more and 7% or less, and more preferably 2% or more and 5% or less.

[0021] The inner diameter of the outer annular portion 2 is appropriately determined according to the application, etc. For example, in the case where a general pneumatic tire is assumed to be substituted, the inner diameter of the outer annular portion 2 may be 420 mm or more and 750 mm or less.

[0022] The width of the outer annular portion 2 is appropriately determined according to the application, etc. For example, in the case where the outer annular portion 2 is assumed to replace a general pneumatic tire, the width of the outer annular portion 2 may be 100 mm or more and 300 mm or less.

[0023] From the viewpoint of improving uniformity, the inner annular portion 3 has a constant thickness in the circumferential direction and the width direction. Although not shown in the figure, the inner circumferential surface of the inner annular portion 3 may be provided with concave and convex portions for maintaining fit so as to be assembled with the axle or the rim. The thickness of the inner annular portion 3 is not particularly limited, but from the viewpoint of being able to sufficiently transmit force to the connecting portion 4 and achieving weight reduction and improved durability, it is preferably Figure 2 The tire cross-sectional height H shown is 2% or more and 7% or less, and more preferably 3% or more and 6% or less.

[0024] The inner diameter of the inner annular portion 3 is appropriately determined in accordance with the size of the rim or axle to which the airless tire 1 is mounted. For example, in the case of replacing a normal pneumatic tire, the inner diameter of the inner annular portion 3 may be 250 mm or more and 500 mm or less.

[0025] The width of the inner annular portion 3 is appropriately determined according to the application, the length of the axle, etc. For example, in the case where a general pneumatic tire is assumed to be substituted, the width of the inner annular portion 3 may be 100 mm or more and 300 mm or less.

[0026] In the pneumatic tire 1, the connecting portion 4 is a member that functions as a spoke that connects the outer annular portion 2 and the inner annular portion 3 at a constant interval. The plurality of connecting portions 4 are independently arranged at a constant interval along the tire circumferential direction D. Figure 1 As shown, when the pneumatic-free tire 1 in an unloaded state is viewed from the front direction along the tire rotation axis, the plurality of connection portions 4 extend linearly in radial directions along the tire radial direction X.

[0027] The connecting portion 4 is formed of an elastic material. The elastic material refers to an elastic material having a tensile modulus of 100 MPa or less calculated from the tensile stress when stretched 10% in a tensile test according to JIS K7321. Specifically, from the viewpoint of ensuring sufficient durability and imparting appropriate rigidity, 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.

[0028] Examples of the elastic material used as the base material of the connection portion 4 include thermoplastic elastomers, cross-linked rubbers, and other resins.

[0029] Examples of the thermoplastic elastomer include polyester elastomers, polyolefin elastomers, polyamide elastomers, polystyrene elastomers, polyvinyl chloride elastomers, and polyurethane elastomers.

[0030] As the rubber material constituting the crosslinked rubber, any one of natural rubber and synthetic rubber can be used. As the synthetic rubber, 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, polyurethane rubber, etc. can be listed. These rubber materials can be used in combination of two or more as needed.

[0031] Examples of other resins include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include polyethylene resins, polystyrene resins, and polyvinyl chloride resins. Examples of thermosetting resins include epoxy resins, phenolic resins, polyurethane resins, silicone resins, polyimide resins, and melamine resins.

[0032] From the viewpoint of molding, processability and cost, among the above-mentioned elastic materials, polyurethane resin is preferably used for the connecting portion 4. In addition, as the elastic material, a foaming material can also be used. That is, a material obtained by foaming the above-mentioned thermoplastic elastomer, cross-linked rubber, or other resin can also be used. In addition, when the outer annular portion 2 and the inner annular portion 3 are made of resin, the connecting portion 4 can also be made of the same resin material as the outer annular portion 2 and the inner annular portion 3 and formed integrally with them.

[0033] The first connecting portion 41 and the second connecting portion 42 are alternately arranged along the tire circumferential direction D to form a plurality of connecting portions 4. Figure 2 As shown, the first connecting portion 41 is arranged to extend from one side Y1 of the outer annular portion 2 in the tire width direction Y toward the other side Y2 of the inner annular portion 3 in the tire width direction Y. The second connecting portion 42 is arranged to extend from the other side Y2 of the outer annular portion 2 in the tire width direction Y toward the one side Y1 of the inner annular portion 3 in the tire width direction Y. The first connecting portion 41 and the second connecting portion 42 adjacent to each other in the tire circumferential direction D are arranged to intersect in a substantially X-shape when viewed from the tire circumferential direction D. The first connecting portion 41 and the second connecting portion 42 viewed from the tire radial direction X are parallel in the tire width direction Y and extend in a direction orthogonal to the tire equatorial plane S.

[0034] like Figure 2As shown, the first connecting portion 41 and the second connecting portion 42 viewed from the tire circumferential direction D have the same shape symmetrical with respect to the tire equatorial plane S. Therefore, the specific shape of each connecting portion 4 is described using the first connecting portion 41. In addition, the tire equatorial plane S is a plane that is orthogonal to the tire rotation axis (tire meridian) and is located at the center position in the tire width direction Y.

[0035] The connecting portion 4 is formed in the shape of a long strip extending obliquely from the outer annular portion 2 toward the inner annular portion 3. Figure 2 as well as Figure 3 As shown in FIG. 1 , the connecting portion 4 is formed such that the plate thickness T is smaller than the plate width W, and the plate thickness direction PT is oriented toward the tire circumferential direction D. That is, the connecting portion 4 is formed in a plate shape extending along the tire radial direction X and the tire width direction Y. In addition, 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 of the connecting portion 4 along the tire width direction Y. Since the connecting portion 4 is such a long plate shape, even if the plate thickness T is reduced, by setting a wider plate width W, the durability of the connecting portion 4 in the case where the plate thickness T is thin can be improved. In addition, by reducing the plate thickness T and increasing the number of the first connecting portion 41 and the second connecting portion 42, the rigidity of the entire tire can be maintained, and the gap between the adjacent connecting portions 4, 4 in the tire circumferential direction D can be reduced. According to this, the dispersion of the ground contact pressure when the tire rolls can be reduced. The more detailed structure of the plate thickness T and the plate width W of the connecting portion 4 will be described later.

[0036] like Figure 2 As shown, the connecting portion 4 has a shape in which a connecting portion 401 connected to the outer annular portion 2 and a connecting portion 402 connected to the inner annular portion 3 are respectively smoothly extended along the tire width direction Y. The connecting portion 401 of the first connecting portion 41 connected to the outer annular portion 2 is provided over a half region of the outer annular portion 2 in the tire width direction.

[0037] That is, one side Y1 of the connection portion 401 of the first connection portion 41 extends to: the 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 connection portion 41 extends to: the tire equatorial plane S arranged at 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 connection portion 41 extends to: the end 3b of the other side Y2 of the inner annular portion 3. One side Y1 of the connection portion 402 of the first connection portion 41 extends to: the tire equatorial plane S arranged at the center of the inner annular portion 3 in the tire width direction.

[0038] Similarly, the other side Y2 of the connection portion 401 of the second connection portion 42 extends to: the end 2b of the other side Y2 of the outer annular portion 2. One side Y1 of the connection portion 401 of the second connection portion 42 extends to: the tire equatorial plane S arranged at the center of the outer annular portion 2 in the tire width direction. One side Y1 of the connection portion 402 of the second connection portion 42 extends to: the 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 connection portion 42 extends to: the tire equatorial plane S arranged at the center of the inner annular portion 3 in the tire width direction.

[0039] The pitch p between the first connecting portion 41 and the second connecting portion 42 adjacent to each other in the tire circumferential direction D is preferably constant and small in the tire circumferential direction D. Specifically, the pitch p is preferably greater than 1 mm and less than 10 mm, and more preferably greater than 1 mm and less than 5 mm. When the pitch p is greater than 10 mm, the ground contact pressure is likely to become uneven in the tire circumferential direction D, and external noise may be generated.

[0040] From the viewpoint of being able to sufficiently support the load from the vehicle while achieving weight reduction, improved power transmission, and improved durability, the number of connecting portions 4 provided in the pneumatic-free tire 1 is preferably 80 or more and 300 or less, and more preferably 100 or more and 200 or less. Figure 1 In the example shown, 50 first connection parts 41 and 50 second connection parts 42 are provided.

[0041] like Figure 4 As shown, the plate thickness T of the connecting portion 4 is different on the outer annular portion 2 side and the inner annular portion 3 side. Specifically, with respect to the plate thickness T of the connecting portion 4, the plate thickness Tr on the inner annular portion 3 side is smaller than the plate thickness Tt on the outer annular portion 2 side. Thus, even if the plate thickness of the connecting portion 4 is increased as a whole, or even if the number of connecting portions 4 along the tire circumferential direction D is increased, the distance between the connecting portions 4, 4 adjacent in the tire circumferential direction D can be ensured on the inner annular portion 3 side. Although there is no limitation on the specific plate thickness Tt and Tr, for example, the plate thickness Tt of the connecting portion 4 on the outer annular portion 2 side may be greater than 18% and less than 22% of the tire cross-sectional height H, and the plate thickness Tr of the connecting portion 4 on the inner annular portion 3 side may be greater than 13% and less than 17% of the tire cross-sectional height H.

[0042] like Figure 2As shown, the plate width W of the connecting portion 4 is different on the outer annular portion 2 side and the inner annular portion 3 side. Specifically, with respect to the plate width W of the connecting portion 4, the plate width Wr on the inner annular portion 3 side is greater than the plate width Wt on the outer annular portion 2 side. Thus, even if the plate thickness Tr on the inner annular portion 3 side is smaller than the plate thickness Tt on the outer annular portion 2 side, the difference in cross-sectional area between the two sides when the connecting portion 4 is cut by a plane orthogonal to the tire radial direction X on the outer annular portion 2 side and the inner annular portion 3 side can be reduced. Accordingly, the strength of the connection portion between the inner annular portion 3 side of the connecting portion 4 where the plate thickness Tr is reduced and the inner annular portion 3 can be improved, thereby improving the durability of the connecting portion 4.

[0043] In addition, the plate width Wt on the outer annular portion 2 side of the connecting portion 4 and the plate width Wr on the inner annular portion 3 side are the plate widths of the portion that is bent and deformed when a load is applied to the connecting portion 4, and are the plate widths of the positions as close as possible to the outer annular portion 2 and the inner annular portion 3. Figure 2 As shown, when the connection portion 401 between the connection portion 4 and the outer annular portion 2 and the connection portion 402 between the connection portion 4 and the inner annular portion 3 are in a shape extending in the tire width direction Y, the plate width Wt on the outer annular portion 2 side of the connection portion 4 is the width of a portion located closer to the inner annular portion 3 than the connection portion 401 and adjacent to the connection portion 401. This portion is located at the outer annular portion 2 side relative to a position of 1 / 2 of the tire cross-sectional height H. In addition, the plate width Wr on the inner annular portion 3 side of the connection portion 4 is the width of a portion located closer to the outer annular portion 2 than the connection portion 402 and adjacent to the connection portion 402. This portion is located at the inner annular portion 3 side relative to a position of 1 / 2 of the tire cross-sectional height H.

[0044] Figure 2 The plate width W of the connecting portion 4 shown in the figure gradually increases from the outer annular portion 2 side toward the inner annular portion 3 side. Specifically, the inner line 4a and the outer line 4b of the connecting portion 4 in the tire width direction Y are formed so as to expand at a constant ratio in the tire width direction Y from the connecting portion 401 side connected to the outer annular portion 2 toward the connecting portion 402 side connected to the inner annular portion 3. Thus, the cross-sectional area of ​​the connecting portion 4 can be made almost uniform over the entire tire cross-sectional height H.

[0045] In addition, the following definition is made, that is, when the connecting portion 4 extending obliquely from the outer annular portion 2 toward the inner annular portion 3 is viewed from the tire circumferential direction D, Figure 2 As shown, the inner line 4a is the line on the side where the intersection angle θ1 with the outer annular portion 2 is an obtuse angle, and the outer line 4b is the line on the side where the intersection angle θ2 with the outer annular portion 2 is an acute angle. Figure 2In the first connecting portion 41 shown, the inner line 4a is a line on the other side Y2 in the tire width direction Y, and the outer line 4b is a line on the one side Y1 in the tire width direction Y. In the second connecting portion 42, the inner line 4a is a line on the one side Y1 in the tire width direction Y, and the outer line 4b is a line on the other side Y2 in the tire width direction Y.

[0046] like Figure 5 As shown, the plate width W of the connecting portion 4 may also gradually increase from the middle portion of the connecting portion 4 in the tire radial direction X toward the inner annular portion 3. Figure 5 In the connecting portion 4 shown, the plate width Wt on the outer annular portion 2 side is constant at a position of 1 / 2 of the tire cross-sectional height H, whereas the plate width Wr on the inner annular portion 3 side is formed to increase toward the inner annular portion 3 side as the position is 1 / 2 of the tire cross-sectional height H. Thus, the connecting portion 4 on the inner annular portion 3 side can be prevented from breaking without impairing the deformation ease of the connecting portion 4 on the outer annular portion 2 side.

[0047] like Figure 6 As shown, the plate width W of the connecting portion 4 may also be increased in stages from the outer annular portion 2 side toward the inner annular portion 3 side. Figure 6 In the connecting portion 4 shown, only the inner line 4a on the inner annular portion 3 side is formed in a step-like shape relative to the position of 1 / 2 of the tire cross-sectional height H, thereby increasing the plate width Wr on the inner annular portion 3 side of the connecting portion 4 in stages. However, the outer line 4b may also be formed in a step-like shape in the same manner. In addition, the inner line 4a and the outer line 4b of the connecting portion 4 may also be formed in a step-like shape throughout the entire tire cross-sectional height H, thereby increasing the plate width W of the connecting portion 4 in stages.

[0048] In addition, when the plate width Wr of the connecting portion 4 on the inner annular portion 3 side is increased, it is not limited to changing the angle and shape of both the inner line 4a and the outer line 4b of the connecting portion 4, but it is also possible to change the angle and shape of only one of the inner line 4a and the outer line 4b. Figure 6 In the embodiment, the shape of the outer line 4b of the connecting portion 4 is not changed, and the inner line 4a is formed in a step shape, thereby making the plate width Wr of the connecting portion 4 on the inner annular portion 3 side larger. Conversely, the shape of the inner line 4a of the connecting portion 4 can be not changed, and the plate width Wr of the connecting portion 4 on the inner annular portion 3 side can be made larger.

[0049] According to the pneumatic-free tire 1 of the present embodiment, the following effects can be produced.

[0050] (1) The pneumatic-free tire 1 according to the present embodiment includes an outer annular portion 2 having a tread portion 5 on its outer periphery, an inner annular portion 3 provided inside the outer annular portion 2, and a plurality of connecting portions 4 connecting the outer annular portion 2 and the inner annular portion 3 and provided along the tire circumferential direction D. The plurality of connecting portions 4 are configured by first connecting portions 41 and second connecting portions 42 being alternately arranged along the tire circumferential direction D, wherein the first connecting portion 41 is provided so as to extend from one side Y1 of the outer annular portion 2 in the tire width direction Y toward the other side Y2 of the inner annular portion 3 in the tire width direction Y, and the second connecting portion 42 is provided so as to extend from the other side Y2 of the outer annular portion 2 in the tire width direction Y toward the one side Y1 of the inner annular portion 3 in the tire width direction Y. The thickness T of each of the plurality of connecting portions 4 along the tire circumferential direction D is smaller on the inner annular portion 3 side than on the outer annular portion 2 side, and the width W of each of the plurality of connecting portions 4 along the tire width direction Y is larger on the inner annular portion 3 side than on the outer annular portion 2 side. Thus, even if the plate thickness T of the connecting portion 4 is increased as a whole, or even if the number of connecting portions 4 along the tire circumferential direction D is increased, the distance between the connecting portions 4 and 4 adjacent in the tire circumferential direction D can be ensured on the inner annular portion 3 side. In addition, even if the plate thickness Tr on the inner annular portion 3 side is smaller than the plate thickness Tt on the outer annular portion 2 side, the difference in cross-sectional area between the two sides when the connecting portion 4 is cut by a plane orthogonal to the tire radial direction X on the outer annular portion 2 side and the inner annular portion 3 side can be reduced. According to this, the strength of the connection portion between the inner annular portion 3 having a reduced plate thickness Tr and the connection portion 4 can be improved, and the durability of the connection portion 4 can be improved.

[0051] (2) In the pneumatic tire 1 of this embodiment, the width W of each of the plurality of connecting portions 4 along the tire width direction Y may be gradually or stepwise increased from the outer annular portion 2 side toward the inner annular portion 3 side. In this way, the cross-sectional area of ​​the connecting portion 4 can be made almost uniform over the entire tire cross-sectional height H.

[0052] (3) In the pneumatic-free tire 1 according to the present embodiment, the width W of each of the plurality of connecting portions 4 along the tire width direction Y may be gradually or stepwise increased from the middle portion of the connecting portion 4 in the tire radial direction X toward the inner annular portion 3, and may be constant from the middle portion toward the outer annular portion 2. Thus, the connection portion 4 on the inner annular portion 3 side may be prevented from breaking without impairing the ease of deformation of the connection portion 4 on the outer annular portion 2 side.

Claims

1. A pneumatic tire, comprising: an outer annular portion having a tread portion on the outer periphery; an inner annular portion arranged inside the outer annular portion; and a plurality of connecting portions connecting the outer annular portion and the inner annular portion and arranged along the tire circumferential direction, characterized in that: The plurality of connecting portions are formed by alternately arranging the first connecting portion and the second connecting portion along the tire circumferential direction, the first connecting portion being arranged to extend 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 the second connecting portion being arranged to extend from the other side of the outer annular portion in the tire width direction toward one side of the inner annular portion in the tire width direction, The thickness of each of the plurality of connecting portions along the tire circumferential direction is smaller on the inner annular portion side than on the outer annular portion side. The width of each of the plurality of connecting portions along the tire width direction is greater on the inner annular portion side than on the outer annular portion side. The outer connecting portion connecting the connecting portion and the outer annular portion and the inner connecting portion connecting the connecting portion and the inner annular portion are shaped to expand in the tire width direction. The width of the connecting portion on the outer annular portion side along the tire width direction is the width of a portion located closer to the inner annular portion than the outer connecting portion and adjacent to the outer connecting portion. The width of the connecting portion on the inner annular portion side along the tire width direction is the width of a portion located closer to the outer annular portion than the inner connecting portion and adjacent to the inner connecting portion. The width of the multiple connecting portions at a position closer to the inner annular portion than 1 / 2 of the tire cross-sectional height along the tire width direction increases gradually or in stages toward the inner annular portion, while the width of the multiple connecting portions at a position closer to the outer annular portion than 1 / 2 of the tire cross-sectional height along the tire width direction is constant, and the inner and outer lines of the multiple connecting portions at a position closer to the inner annular portion than 1 / 2 of the tire cross-sectional height are inclined from 1 / 2 of the tire cross-sectional height toward the inner annular portion in opposite directions in the tire width direction.

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