阅读说明：本技术 充气轮胎 (Pneumatic tire ) 是由 大田和贵 于 2019-06-06 设计创作，主要内容包括：提供一种充气轮胎,其能够降低胎面部的接地端附近的刚性而抑制偏磨损的发生,同时还能够缓和局部的应力集中,从而能够提高耐久性。充气轮胎具备：胎面部(16)、胎侧部(14)、设置在胎面部(16)与胎侧部(14)之间的支承部(18)、以及沿着周向而设置在支承部(18)的凹缺部(50),凹缺部(50)的底面的截面形状形成为如下所述而得到的曲线形状,即：以随着从轮胎径向外侧(Ro)越趋向内侧(Ri)而曲率半径越发变小的方式来配置曲率半径不同的圆弧(51、52),并将邻接的圆弧(51、52)在具有共用切线的切点处连接起来而得到的曲线形状。(Provided is a pneumatic tire which can reduce the rigidity near the contact edge of a tread portion to suppress the occurrence of uneven wear, and can alleviate local stress concentration to improve the durability. A pneumatic tire is provided with: the tread portion (16), the sidewall portion (14), a support portion (18) provided between the tread portion (16) and the sidewall portion (14), and a recess portion (50) provided in the support portion (18) along the circumferential direction, wherein the cross-sectional shape of the bottom surface of the recess portion (50) is formed in a curved shape obtained as follows: the curved shape is obtained by arranging arcs (51, 52) having different curvature radii so that the curvature radius becomes smaller as going to the inner side (Ri) from the outer side (Ro) in the tire radial direction, and connecting adjacent arcs (51, 52) at a tangent point having a common tangent.)

1. A pneumatic tire is provided with: a tread portion, a sidewall portion, a support portion provided between the tread portion and the sidewall portion, and a depressed portion depressed from an outer surface of the support portion toward an inner side in a tire width direction, the pneumatic tire being characterized in that,

the cross-sectional shape of the bottom surface of the indentation is a curved shape obtained by: the curved shape is obtained by arranging a plurality of arcs having different curvature radii so that the curvature radius becomes smaller as going to the inner side from the outer side in the tire radial direction, and connecting adjacent arcs at a tangent point having a common tangent.

2. A pneumatic tire according to claim 1,

the tread portion is provided with a belt,

a portion of the bottom surface of the indentation, which portion is formed of an arc having a smallest radius of curvature, is formed by: a position overlapping with at least a part of an end portion of the belt in the tire radial direction.

3. A pneumatic tire according to claim 1 or 2,

the disclosed device is provided with: a plurality of beads provided along the tire circumferential direction between the tire radial direction inner side of the cutout portion and the tire maximum width position, and a recessed portion formed by the beads and extending along the tire circumferential direction.

4. A pneumatic tire according to claim 3,

the disclosed device is provided with: a plurality of the recesses are arranged side by side in a tire radial direction.

5. A pneumatic tire according to claim 4,

the cross-sectional shape of the bottom surface is formed into an arc shape having a large radius of curvature as the concave portion is located more inward in the tire radial direction.

6. A pneumatic tire according to any one of claims 1 to 5,

the tread portion is provided with a belt,

the cross-sectional shape of the bottom surface of the indentation is formed as follows: a curved shape obtained by connecting 2 circular arcs having different radii of curvature,

a ratio M/L of a length M from the tire width direction center to a position where 2 arcs of the bottom surface of the cutout are connected to a length L from the tire width direction center to a belt end located at the tire width direction outermost position of the belt is: 1.03 to 1.11.

7. A pneumatic tire according to any one of claims 1 to 6,

an angle formed by a tangent line tangent to the outer end of the indentation in the tire radial direction and the tire radial direction is less than 35 degrees.

8. A pneumatic tire according to any one of claims 1 to 7,

the pneumatic tire is a tire for a truck or bus.

Technical Field

The present invention relates to a pneumatic tire.

Background

In a pneumatic tire, during normal running, the ground contact pressure is high in the vicinity of the ground contact end of the tread portion. Thus, sometimes: such partial wear in which the amount of wear in the vicinity of the ground terminal is larger than that of the other portions. As a method for suppressing such uneven wear, there has been proposed a method in which a support portion provided between a tread portion and a sidewall portion is provided with: the recessed portion recessed inward in the tire width direction can reduce the rigidity in the vicinity of the ground contact edge of the tread portion to reduce the ground contact pressure, thereby suppressing the occurrence of uneven wear.

Disclosure of Invention

However, according to the above patent documents 1 and 2, since the cross-sectional shape of the bottom surface of the concave portion provided in the support portion is formed by a single arc shape, deformation due to a load received in the vicinity of the ground contact edge of the tread portion is likely to concentrate on the top portion of the bottom surface of the concave portion, and thus, breakage is likely to occur with the top portion of the bottom surface as a starting point.

In view of the above-described problems, an object of the present invention is to provide a pneumatic tire in which a concave portion is provided in a support portion, and the rigidity in the vicinity of a ground contact edge of a tread portion is reduced to suppress the occurrence of uneven wear, and the occurrence of local concentration of deformation at a top portion of a bottom surface of the concave portion is suppressed, thereby improving durability.

According to the present embodiment, the following aspects [1] to [8] are provided.

[1] A pneumatic tire is provided with: a tread portion, a sidewall portion, a support portion provided between the tread portion and the sidewall portion, and a depressed portion depressed from an outer surface of the support portion toward an inner side in a tire width direction, a cross-sectional shape of a bottom surface of the depressed portion being formed in a curved shape obtained as follows: the tire has a curved shape in which a plurality of arcs having different radii of curvature are arranged so that the radii of curvature become smaller as going inward from the outer side in the tire radial direction, and adjacent arcs are connected at a tangent point having a common tangent.

[2] The pneumatic tire according to [1], wherein a tread portion is provided with a belt, and a portion of a bottom surface of the indentation portion, which portion is formed of an arc having a smallest radius of curvature, is formed by: a position overlapping with at least a part of an end portion of the belt in the tire radial direction.

[3] The pneumatic tire according to the above [1] or [2], comprising: a plurality of beads provided along the tire circumferential direction between the tire radial direction inner side of the cutout portion and the tire maximum width position, and a recessed portion formed by the beads and extending along the tire circumferential direction.

[4] The pneumatic tire according to [3], comprising: a plurality of the recesses are arranged side by side in a tire radial direction.

[5] The pneumatic tire according to the above [4], wherein the cross-sectional shape of the bottom surface is formed in an arc shape having a larger radius of curvature as the concave portion is located more inward in the tire radial direction.

[6] The pneumatic tire according to any one of the above [1] to [5], wherein the tread portion includes a belt, and a cross-sectional shape of a bottom surface of the depressed portion is formed such that: a curve shape obtained by connecting 2 arcs having different radii of curvature, wherein a ratio M/L of a length M from a tire width direction center to a position where 2 arcs among bottom surfaces of the recessed portions are connected to a length L from the tire width direction center to a belt end located at an outermost position in the tire width direction among the belts is: 1.03 to 1.11.

[7] The pneumatic tire according to any one of the above [1] to [6], wherein an angle formed by a tangent line that is tangent to an outer end of the indentation in the tire radial direction and the tire radial direction is less than 35 degrees.

[8] The pneumatic tire according to any one of the above [1] to [7], wherein the pneumatic tire is a tire for a truck or a bus.

As described above, the cross-sectional shape of the bottom surface of the indentation that is recessed inward in the tire width direction from the outer surface of the support portion is a curved shape obtained by: since the plurality of arcs having different radii of curvature are arranged so that the radii of curvature become smaller as going inward from the outer side in the tire radial direction and the curved shape is obtained by connecting adjacent arcs at the tangent points having a common tangent line, deformation caused by a load applied in the vicinity of the contact edge of the tread portion is dispersed over a wide range of the depressed portion, and the durability of the pneumatic tire can be improved.

Drawings

Fig. 1 is a half sectional view of a pneumatic tire according to a first embodiment of the present invention.

Fig. 2 is an enlarged view of a main portion of the pneumatic tire of fig. 1.

Fig. 3 is a half sectional view of a pneumatic tire according to a second embodiment of the present invention.

Fig. 4 is an enlarged view of a main portion of the pneumatic tire of fig. 3.

Description of reference numerals:

10 … tire, 14 … sidewall portion, 16 … tread portion, 18 … support portion, 42 … shoulder land portion, 48 … inclined portion, 49 … zigzag portion, 50 … indentation portion, 50a … tire radial direction outer end, 50b … tire radial direction outer end, 51a … upper side arc portion, 51b … lower side arc portion, 61 … 1 st ridge, 62 … 2 nd ridge, 63 … rd 3 ridge, 64 … th 4 ridge, 71 … 1 st indentation, 72 … nd 2 nd indentation, 73 … rd 3 rd indentation, 74 … th indentation.

Detailed Description

(embodiment 1)

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a tire meridian cross section showing an example of a pneumatic tire 10 according to the present embodiment, and shows only a right side half cross section.

The pneumatic tire 10 of fig. 1 includes: a pair of left and right bead portions 12; a pair of left and right sidewall portions 14 extending radially outward from the bead portion 12; a tread portion 16 constituting a tread surface; and a pair of left and right support portions 18 disposed on the tire radial direction inner side Ri of the tread portion 16. Here, the support portion 18 is: a boundary region between the tread portion 16 and the sidewall portion 14 is provided: the tread portion 16 and the sidewall portion 14 are connected to each other.

The pneumatic tire 10 includes: and a carcass ply 20 annularly disposed between the pair of bead portions 12. The pair of bead units 12 are embedded with: an annular bead core 22.

The carcass ply 20 is locked to the bead core 22 in the bead portion 12 from the tread portion 16 via the support portion 18 and the sidewall portion 14, and the carcass ply 20 reinforces the above-described respective portions 12, 14, 16, 18. In this example, both ends of the carcass ply 20 are folded back and locked around the bead core 22 from the inner side Wi to the outer side Wo in the tire width direction. The carcass ply 20 is provided with: a liner 24 for maintaining air pressure.

The carcass ply 20 is composed of at least 1 ply, in this example, 1 ply, which is obtained by arranging a metal cord such as a steel cord or an organic fiber cord such as a polyester fiber, a rayon fiber, an aramid fiber, or a nylon fiber at a predetermined angle (for example, 70 ° to 90 °) with respect to the tire circumferential direction and coating the same with an upper layer rubber. As the cord constituting the carcass ply 20, for example, a metal cord such as a steel cord is preferably used.

In the sidewall portion 14, and outside the carcass ply 20 (i.e., on the tire outer surface side), there are provided: sidewall rubber 32. Further, in the bead portion 12, on the outer peripheral side of the bead core 22, there are disposed: and a bead filler 34 made of a hard rubber material and extending outward in the radial direction of the tire in a tapered shape.

A belt 26 is disposed on the outer circumferential side of the carcass ply 20 in the tread portion 16. That is, in the tread portion 16, the belt 26 is provided between the carcass ply 20 and the tread rubber 28. The belt 26 is formed of a plurality of intersecting belt cords arranged at a predetermined angle (for example, 10 ° to 35 °) with respect to the tire circumferential direction. As the belt cord, a steel cord, or an organic fiber cord having a relatively high tension is used.

The belt 26 in this example has: the 4-layer structure of the 1 st belt 26A located at the innermost Ri position in the tire radial direction, the 2 nd belt 26B, the 3 rd belt 26C laminated in this order on the outer peripheral side of the 1 st belt 26A, and the 4 th belt 26D located at the outermost Ro position in the tire radial direction, the 2 nd belt 26B being the largest width belt having the largest width.

On the surface of tread portion 16, there are provided: a plurality of main grooves 36 extending in the tire circumferential direction. Specifically, the main groove 36 includes: a pair of central main grooves 36A disposed on both sides with the tire equatorial plane CL therebetween; and a pair of shoulder main grooves 36B provided on the tire width direction outer sides Wo of the pair of center main grooves 36A. The tire width direction outer side Wo is: on the side away from the tire equatorial plane CL in the tire width direction W.

In the tread portion 16, the 4 main grooves 36 described above form, between the 2 central main grooves 36A: the center land portion 38 has, between the center main groove 36A and the shoulder main groove 36B: the intermediate land portion 40 is formed on the tire width direction outer sides Wo of the 2 shoulder main grooves 36B with: shoulder land portions 42.

In this example, the center land portion 38, the intermediate land portion 40, and the shoulder land portions 42 are constituted by ribs that are continuous in the tire circumferential direction. The center land portion 38, the center land portion 40, and the shoulder land portion 42 may be: and a block row divided by the lateral grooves in the tire circumferential direction.

The outer end in the tire width direction of the tread surface of the shoulder land portion 42 constitutes a ground contact end E. A support portion 18 extending toward the tire radial direction inner side Ri and constituting an upper portion of the tire side surface is connected to the ground contact end E.

As shown in fig. 1 and 2, the support portion 18 has, on its outer surface: an inclined portion 48 extending from the ground contact end E toward the tire radial direction inner side Ri, and an indentation portion 50 provided from the inclined portion 48 toward the tire radial direction inner side.

Inclined portion 48 is inclined so as to widen toward tire width direction outer side Wo as it goes toward tire radial direction inner side Ri from contact edge E (i.e., so as to narrow as it goes toward tire radial direction outer side Wo). The inclined portion 48 reduces the rigidity of the shoulder land portion 42 on the side of the ground contact end E, thereby improving the cornering performance when the tire crosses a height difference on a road surface such as a rut.

In the present embodiment, as shown in fig. 2, the inclined portion 48 is provided on the leading end side (outer side in the tire width direction) with: a meandering portion 49 meandering toward the tire radial direction inner side Ri is connected to a tip end of the meandering portion 49: the outer end 50a of the indentation 50 in the tire radial direction.

The indentations 50 are: a groove recessed from the outer surface of the support portion 18 toward the tire width direction inner side Wi and extending in the tire circumferential direction. Preferably, the indentation 50 is recessed from the outer surface of the support portion 18 toward the tire width direction inner side Wi such that at least a part of the bottom surface of the indentation 50 is located at the tire width direction inner side Wi with respect to a straight line extending from the tire radial direction outer end 50a of the indentation 50 toward the tire radial direction inner side Ri.

The cross-sectional shape of the bottom surface of the recessed portion 50 is a curved shape obtained as follows: a curved shape in which a plurality of arcs having different radii of curvature are arranged so that the radius of curvature decreases as the radius of curvature increases from the tire radial direction outer side Ro toward the tire radial direction inner side Ri, and adjacent arcs are connected at a tangent point having a common tangent line.

Specifically, the bottom surface of the indentation 50 is formed by an upper arc 51a provided on the tire radial direction outer side Ro and a lower arc 51b provided on the tire radial direction inner side Ri of the upper arc 51 a. The upper arc portion 51a is: the lower arc portion 51b is a curved surface having a cross section formed by an arc having a curvature radius ra: a curved surface having a cross section formed by a circular arc with a smaller radius of curvature rb than radius of curvature ra. As an example, the radius of curvature ra of the cross section of the upper circular arc portion 51a may be set to 30mm, and the radius of curvature rb of the cross section of the lower circular arc portion 51b may be set to 6 mm.

The upper arc portion 51a and the lower arc portion 51b constituting the bottom surface of the depressed portion 50 are joined to each other with a common tangent line at the joint portion C, and the upper arc portion and the lower arc portion can be joined smoothly without forming a ridge protruding from the bottom surface of the depressed portion 50 toward the tire width direction outer side Wo at the joint portion C.

The recessed portion 50 or the connection portion C connecting the upper arc portion 51a and the lower arc portion 51B may be provided at any position on the support portion 18. Preferably, the indentation 50 is disposed such that a lower arc portion 51b provided on the innermost Ri in the tire radial direction, among the arc portions 51a, 51b, overlaps at least a portion of the end portion of the belt 26 in the tire radial direction R. In other words, it is preferable that the recessed portion 50 be disposed so that at least a part of the end portion of the belt 26 is positioned on the tire width direction inner side Wi of the lower circular arc portion 51 b. More preferably, as shown in fig. 2, the depressed portion 50 is disposed so that a connecting portion C where the upper arc portion 51a and the lower arc portion 51b are connected and an end portion of the 4 th belt 26D located at the outermost side Ro in the tire radial direction overlap in the tire radial direction R.

Further, a ratio p (M/L) of a length M from the tire equatorial plane CL to a connecting portion C where the upper arc portion 51a and the lower arc portion 51B are connected to a length L from a tire widthwise central portion (i.e., the tire equatorial plane CL) to a tire widthwise end of the 2 nd belt 26B having the largest width is preferably 1.03 to 1.11. By setting the ratio p to 1.03 or more, the rubber thickness from the end of the belt 26 to the bottom surface of the depressed portion 50 can be sufficiently ensured, and the tread rubber is less likely to peel off from the end of the belt 26. Further, by setting the ratio p to 1.11 or less, the amount of depression of the depressed portion 50 can be sufficiently ensured, and the ground contact pressure in the vicinity of the ground contact end E can be reduced.

Preferably, a tangent n to the tire radial direction outer end 50a of the indentation 50 is inclined toward the tire width direction inner side Wi with respect to the tire radial direction R, and an angle θ formed with the tire radial direction R is greater than 10 degrees and less than 35 degrees. By setting the angle θ to be larger than 10 degrees, the amount of depression of the depressed portion 50 can be sufficiently ensured, and the ground contact pressure in the vicinity of the ground contact end E can be reduced. Further, by setting angle θ to less than 35 degrees, deformation due to a load received in the vicinity of ground contact edge E of tread portion 16 is less likely to concentrate on connecting portion C formed on the bottom surface of recessed portion 50, and occurrence of cracking can be suppressed.

In addition, the above-mentioned respective dimensions in the present specification are, except for the case where specifically mentioned: the pneumatic tire is mounted on a regular rim and has a dimension in a normal state of no load filled with a regular internal pressure. In the present specification, the ground terminal E means: the pneumatic tire is assembled to a regular rim, is vertically placed on a flat road surface in a state filled with a regular internal pressure, and is applied with a regular load, and the end in the tire width direction of the tread surface that is in contact with the road surface.

The normal rim is: a rim determined for each tire in accordance with a specification system including a specification under which the tire is based; for example, it is "standard rim" if JATMA, "design rim" if TRA, and "measurement rim" if ETRTO. The normal internal pressure is: in a specification system including the specification to which the tire is subjected, the air pressure determined for each tire in accordance with each specification is the highest air pressure in case of JATMA, the maximum value described in the table "tire load limit under various cold inflation pressures" in case of TRA, and the "inflation pressure" in case of ETRTO. For example, when the tire size is 295/75R22.5(LR ═ G), the normal internal pressure is 760 kPa. The normal load is: in a specification system including the specification to which the tire is subjected, the load determined for each tire in accordance with each specification is the maximum load capacity if JATMA, the maximum value described in the above table if TRA, and the "load capacity" if ETRTO, but when the tire is used for a passenger vehicle, the load corresponding to 88% of the load.

According to the pneumatic tire 10 of the present embodiment as described above, the support portion 18 is provided with: since the depressed portion 50 depressed toward the tire width direction inner side Wi, the rigidity of the tread portion 16 in the vicinity of the ground contact edge E can be reduced, the ground contact performance in the vicinity of the ground contact edge E can be improved (the ground contact pressure distribution of the entire ground contact surface is made uniform), and the occurrence of uneven wear can be suppressed.

The bottom surface of the recessed portion 50 is composed of an upper arc portion 51a and a lower arc portion 51b, and the cross-sectional shape of the bottom surface of the recessed portion 50 is a curved shape obtained as follows: a curved shape in which a plurality of arcs having different radii of curvature are arranged so that the radius of curvature decreases as the radius of curvature increases from the tire radial direction outer side Ro toward the tire radial direction inner side Ri, and adjacent arcs are connected at a tangent point having a common tangent line. Thus, according to pneumatic tire 10, deformation due to a load received in the vicinity of ground contact edge E of tread portion 16 can be dispersed over a wide range of depressed portion 50, and tire durability can be improved.

In the pneumatic tire 10 of the present embodiment, the lower arc portion 51b provided on the innermost Ri in the tire radial direction among the arc portions 51, 52 overlaps with the end portion of the belt 26 in the tire radial direction R. Accordingly, the ends of the belt 26 are located: the position of the lower arc portion 51b on the tire width direction inner side Wi, which has a small radius of curvature and is easily deformed, can appropriately restrict the bending deformation of the lower arc portion 51b, and can make the bending degree of the notch portion 50 uniform as a whole. This makes it possible to easily disperse deformation due to a load applied in the vicinity of the ground contact edge E of the tread portion 16 to the entire indentation 50, thereby further improving the tire durability.

Further, since the indentations 50 are provided in the support portion 18 in such a manner that the connecting portion C where the upper arc portion 51a and the lower arc portion 51b are connected overlaps with the end portion of the 4 th belt 26D in the tire radial direction R, deformation can be restricted in the vicinity of the connecting portion C of the lower arc portion 51b, which is particularly susceptible to flexural deformation, which enables the deformation to be more easily dispersed uniformly over the entirety of the indentations 50, thereby enabling improvement in tire durability.

(embodiment 2)

Next, embodiment 2 of the present invention will be described with reference to fig. 3 and 4. Note that the same portions as those in embodiment 1 will not be described, and only different portions will be described.

In the present embodiment, between the tire radial direction inner side Ri of the indentation 50 provided in the support portion 18 and the tire maximum width position P, there are provided: a plurality of ribs 61, 62, 63, 64, and recesses 71, 72, 73, 74 defined by the ribs 61, 62, 63, 64.

The tire maximum width position P is: in the tire width direction W, at the outermost position on the surface of the sidewall portion 14, that is, at the position on the sidewall portion surface where the maximum width of the tire is obtained. The maximum width of the tire is also referred to as a cross-sectional width, and is a width excluding projections such as patterns and characters on the surface of the sidewall portion.

The plurality of ribs 61, 62, 63, 64 are: projections that project from the outer surface of the support portion 18 toward the tire width direction outer side Wo and extend in the tire circumferential direction, the projections being provided substantially parallel to each other.

Between the 1 st ridge 61 provided at the tire radial direction outermost side Ro and the tire radial direction inner end 50b of the depressed portion 50, there are formed: and a 1 st recessed portion 71 extending in the tire circumferential direction. The 1 st recess 71 includes: the cross-sectional shape is a bottom surface of a circular arc shape having a radius of curvature r 1.

The 2 nd ridge 62 and the 1 st ridge 61 adjacent to the tire radial direction outer side Ro are formed with: and a 2 nd recessed portion 72 extending in the tire circumferential direction. The 2 nd recess 72 has: the sectional shape is a bottom surface of a circular arc shape having a curvature radius r 2.

The 3 rd ridge 63 and the 2 nd ridge 62 adjacent to the tire radial direction outer side Ro are formed with: and a 3 rd recessed portion 73 extending in the tire circumferential direction. The 3 rd recess 73 has: the sectional shape is a bottom surface of a circular arc shape having a curvature radius r 3.

The 4 th ridge 64 and the 3 rd ridge 63 adjacent to the tire radial direction outer side Ro are formed with: and a 4 th recessed portion 74 extending in the tire circumferential direction. The 4 th recess 74 has: the sectional shape is a bottom surface of a circular arc shape having a curvature radius r 4.

The first recess 71 is disposed substantially parallel to each other in the tire circumferential direction and arranged in the tire radial direction R in order from the 1 st recess 71 toward the tire radial direction inner side Ri: 1 st recess 71, 2 nd recess 72, 3 rd recess 73, and 4 th recess 74.

The radii of curvature r1, r2, and r3 of the arcs constituting the bottom surfaces of the 1 st, 2 nd, and 3 rd recesses 71, 72, and 73 are set to: the more the recess located at the tire radial direction inner side ri is, the larger the recess becomes (i.e., r1 < r2 < r3), the radius of curvature r4 of the bottom face constituting the 4 th recess 74 is set to: the same size as the radius of curvature r3 of the arc constituting the bottom surface of the 3 rd recessed portion 73.

In the present embodiment, since there are provided, from the tire radial direction inner side Ri of the depressed portion 50 to the tire maximum width position P: since the concave portions 71, 72, 73, 74 are formed by dividing the plurality of ridges 61, 62, 63, 64 and extend in the tire circumferential direction, not only the deformation of the concave portion 50 due to the load received in the vicinity of the ground contact edge E of the tread portion 16 is dispersed, but also the deformation is dispersed in the concave portions 71, 72, 73, 74, so that uneven wear in the vicinity of the ground contact edge of the tread portion can be suppressed, and the tire durability can be improved.

In the present embodiment, the cross-sectional shape of the bottom surface of the recess located at the inner side Ri in the tire radial direction is formed as follows: the arc shape with a larger radius of curvature smoothly changes the shape of the support portion 18 in the tire radial direction R, so that the indentation 50 and the plurality of recesses 71, 72, 73, and 74 can be provided in the support portion 18 while suppressing visual discomfort.

(modification example)

The above embodiments are presented as examples and are not intended to limit the scope of the invention. The new embodiment may be implemented in other various forms, and various omissions, substitutions, and changes may be made without departing from the spirit of the invention.

For example, in the above-described embodiment, the case where the bottom surface of the notch 50 is formed of 2 arcs having different radii of curvature has been described, but the bottom surface may be formed in a curved shape obtained as follows: a curved shape in which 3 or more arcs are arranged so that the radius of curvature decreases as the radius of curvature increases from the outer side to the inner side in the tire radial direction, and adjacent arcs are connected at a tangent point having a common tangent.

The dimples 50 may be formed in a completely continuous ring shape in the tire circumferential direction, or may be formed intermittently at each location in the circumferential direction.

The present invention is suitable for use in pneumatic tires for high loads such as trucks and buses, but is not limited thereto, and can be applied to various pneumatic tires for passenger cars, light trucks, and the like.