pneumatic tires

Abstract

To provide a pneumatic tire that can suppress the occurrence of cracks near the inner edge in the radial direction of the side ridge. [Solution] The tire 1 is a pneumatic tire equipped with a sidewall 20, the sidewall 20 includes a side ridge portion 70 positioned radially outward from the sidewall 20, and the sidewall 20 has a serration portion 80 that extends substantially radially from the sidewall and includes a plurality of protrusions 81 that contact at least the side wall 71 of the side ridge portion 70.

Description

Technical Field

[0001] The present invention relates to pneumatic tires.

Background Art

[0002] Conventionally, a pneumatic tire is known that includes a pair of beads fitted and fixed to a rim of a tire wheel, sidewalls each extending radially outward of the tire from those beads, and a tread extending between the sidewalls. Patent Document 1 shows a pneumatic tire provided with side blocks near the tread of the sidewall. This side block is a side ridge higher than the surrounding tire surface and is supposed to have a function of obtaining traction against, for example, sand, mud, or snow on the road surface and enhancing running performance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a side ridge as described above is provided on the sidewall, stress is likely to be applied near the inner edge in the tire radial direction of the side ridge, and there is a concern that deflection may occur and cracks may occur. In particular, in tires with a large tire cross-sectional height such as for SUVs, this tendency is likely to be prominent, so there is room for improvement.

[0005] Therefore, an object of the present invention is to provide a pneumatic tire capable of suppressing the occurrence of cracks near the inner edge in the tire radial direction of the side ridge.

Means for Solving the Problems

[0006] The pneumatic tire of the present invention is a pneumatic tire having a sidewall, wherein the sidewall includes a side ridge portion that is located radially outward of the tire and rises from the sidewall, and the sidewall has a serration portion that extends substantially radially of the tire and includes a plurality of protrusions that contact at least the side wall of the side ridge portion. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a pneumatic tire that can suppress the occurrence of cracks near the inner edge of the side ridge in the radial direction of the tire. [Brief explanation of the drawing]

[0008] [Figure 1] This is a half-cross-sectional view in the axial direction of a tire (pneumatic tire) according to the embodiment. [Figure 2] This is a perspective view of a tire according to an embodiment, partially showing a portion of the tire in the circumferential direction. [Figure 3] This is a magnified perspective view of a portion of Figure 2. [Figure 4] This is a partial side view of the sidewall showing a portion of the serrations in the tire circumferential direction of the tire according to the embodiment. [Figure 5] Figure 4 is a VV cross-sectional view. [Figure 6] This is a cross-sectional view taken from VI-VI in Figure 4. [Modes for carrying out the invention]

[0009] The embodiments will be described below with reference to the drawings. Figure 1 is a diagram showing the internal structure of a tire 1, which is a pneumatic tire according to the embodiment, and is a half-cross-sectional view showing the right half. Figure 2 is a perspective view partially showing a part of the tire in the circumferential direction, and is a perspective view of the tire side.

[0010] The tire 1 according to this embodiment is, for example, a pneumatic tire for a passenger car. The configuration of the tire 1 according to this embodiment can be used for various vehicles other than passenger cars, such as light trucks, trucks, and buses.

[0011] The cross-sectional view in Figure 1 is a half-section view of the tire in the axial direction (tire meridian half-section view) under no-load conditions, with tire 1 mounted on a standard rim (not shown) and filled to the standard internal pressure. The standard rim is the rim specified for each tire in the standard system that includes the standard on which the tire is based. For example, it is the standard rim for JATMA, and the "Measuring Rim" for TRA and ETRTO. The standard internal pressure is the air pressure specified for each tire in the standard system that includes the standard on which the tire is based. For truck and bus tires and light truck tires, it is the maximum air pressure for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and the "INFLATION PRESSURE" for ETRTO. For passenger car tires, it is usually 180 kPa, but for tires marked "Extra Load" or "Reinforced," it is 220 kPa.

[0012] In Figure 1, the symbol S1 represents the tire equatorial plane. The tire equatorial plane S1 is a plane perpendicular to the tire rotation axis (tire meridian) and located at the center of the tire axial direction. The basic internal structure of tire 1 is symmetrical in the tire axial cross-section with respect to the tire equatorial plane S1.

[0013] Here, the tire axis direction is the direction parallel to the tire rotation axis, which is the left-right direction in the cross-sectional view of Figure 1. In Figure 1, it is shown as the tire axis direction X. The inward direction in the tire axis direction is the direction approaching the tire equatorial plane S1, which is the left side of the paper in Figure 1. The outward direction in the tire axis direction is the direction away from the tire equatorial plane S1, which is the right side of the paper in Figure 1. The tire radial direction is the direction perpendicular to the tire rotation axis, which is the up-down direction in the paper in Figure 1. In Figure 1, it is shown as the tire radial direction Y. The outward direction in the tire radial direction is the direction away from the tire rotation axis, which is the upper side of the paper in Figure 1. The inward direction in the tire radial direction is the direction approaching the tire rotation axis, which is the lower side of the paper in Figure 1.

[0014] The tire 1 comprises a pair of beads 10 provided on both sides of the tire axial direction, a pair of sidewalls 20 extending radially outward from each of the pair of beads 10, a tread 30 positioned between the pair of sidewalls 20, a pair of shoulders 40 which are the transitions from each of the pair of sidewalls 20 to the tread 30, a carcass ply 50 positioned across the pair of beads 10, and an inner liner 60 positioned on the inner side of the carcass ply 50.

[0015] A pair of beads 10 are positioned on both sides in the tire axial direction and at the inner ends in the tire radial direction. Each bead 10 includes a bead core 11, a bead filler 12 extending radially outward from the bead core 11, a chaff 13, and a rim strip rubber 14.

[0016] The bead core 11 is an annular member in which a metal bead wire wound multiple times in the tire circumferential direction is coated with rubber. The bead core 11 is a member that serves to fix the air-filled tire 1 to the rim of the tire wheel. The bead filler 12 has a tapered shape with a decreasing thickness as it extends from the inner side in the tire radial direction to the outer side in the tire radial direction. The bead filler 12 is provided to increase the rigidity of the peripheral portion of the bead 10 and ensure high maneuverability and stability. The bead filler 12 is composed of, for example, rubber having a higher hardness than the surrounding rubber members. The bead filler 12 is joined to the outer surface of the bead core 11 in the tire radial direction.

[0017] <M The chafer 13 is provided in a manner that further surrounds the outside of the carcass ply 50 surrounding the bead core 11 and the bead filler 12.

[0018] 》 The rim strip rubber 14 is disposed on the outside in the tire axial direction of a part of the carcass ply 50 and the chafer 13. The rim strip rubber 14 extends to near the inner end in the tire radial direction of the chafer 13.

[0019] The sidewall 20 includes a sidewall rubber 21 disposed on the outside in the tire axial direction of the carcass ply 50. The sidewall rubber 21 is the rubber that constitutes the outer surface of the tire 1. The sidewall rubber 21 is the part that flexes the most when the tire 1 performs a cushioning action, and usually, a flexible rubber having fatigue resistance is adopted.

[0020] The outer end 21a in the tire radial direction of the sidewall rubber 21 is covered by the outer end 37a in the tire axial direction of the tread rubber 37 described later. The inner end 21b in the tire radial direction of the sidewall rubber 21 covers the outer end 14a in the tire radial direction of the rim strip rubber 14. The rim strip rubber 14 has a rim line 14b formed by protrusions along the tire circumferential direction at approximately the center in its tire radial direction. The inner end 21b in the tire radial direction of the sidewall rubber 21 extends to near the rim line 14b.

[0021] The tread 30 includes an endless belt 31, a cap ply 34, and tread rubber 37. The belt 31 is disposed on the outer side in the tire radial direction of the carcass ply 50. The cap ply 34 is disposed on the outer side in the tire radial direction of the belt 31. The tread rubber 37 is disposed on the outer side in the tire radial direction of the cap ply 34.

[0022] The belt 31 is a member that reinforces the tread 30. The belt 31 of the embodiment has a two-layer structure including an inner belt 32 disposed on the outer side in the tire radial direction of the carcass ply 50 and an outer belt 33 disposed on the outer side in the tire radial direction of the inner belt 32. Both the inner belt 32 and the outer belt 33 have a structure in which a plurality of belt cords such as steel cords are covered with rubber. The inner belt 32 is wider than the outer belt 33. By providing the belt 31, the rigidity of the tire 1 is ensured and the grounding property of the tread 30 with respect to the road surface is improved. Note that the belt 31 is not limited to a two-layer structure and may have a single-layer or three-layer or more structure.

[0023] The cap ply 34 is a member that reinforces the tread 30 together with the belt 31. The cap ply 34 of the embodiment is wider than the belt 31 and covers the entire belt 31 from the outer surface side of the tire. The cap ply 34 has a structure in which a plurality of insulating organic fiber cords such as polyamide fibers are covered with rubber. The outer end 34a of the cap ply 34 in the tire axial direction is folded back inward in the tire axial direction and overlaps inward in the tire radial direction. By providing the cap ply 34, it is possible to improve the durability of the tire 1 and reduce the road noise during running. Note that the cap ply 34 is not limited to a single-layer structure as in the embodiment and may have a two-layer or three-layer or more structure.

[0024] As shown in Figure 2, the tread rubber 37 includes a plurality of grooves 38 and a plurality of blocks 39 partitioned by the plurality of grooves 38. The grooves 38 and blocks 39 etc. form a tread pattern on the surface of the tread 30. In Figure 1, the grooves 38 and blocks 39 are not shown. As shown in Figure 1, the outer edge 37a of the tread rubber 37 in the tire axial direction covers the outer edge 34a of the cap ply 34 in the tire axial direction and the outer edge 21a of the sidewall rubber 21 in the tire radial direction.

[0025] The shoulder 40 is the portion that transitions from the tread 30 to the sidewall 20 while bending. In this embodiment, the shoulder 40 includes the axial outer end 37a of the tread rubber 37 and the radial outer end 21a of the sidewall rubber 21.

[0026] As shown in Figures 1 and 2, the shoulder 40 further includes an annular projection 41 along the circumferential direction of the tire and a plurality of shoulder blocks 42 positioned radially outward of the annular projection 41.

[0027] As shown in Figure 1, the annular projection 41 covers the radially outer end 21a of the sidewall rubber 21 and the axially outer end 37a of the tread rubber 37. An annular line 41a is formed on the outer surface of the annular projection 41, consisting of projection tips along the circumferential direction of the tire. The annular projection 41 has a circumferential wall 41b on the radially inner side of the annular line 41a. The circumferential wall 41b has a curved surface with a concave cross-section extending from the annular line 41a to the surface of the sidewall 20.

[0028] As shown in Figure 2, multiple shoulder blocks 42 are arranged in the circumferential direction of the tire. As shown in Figure 1, the shoulder blocks 42 cover the radially outer side of the annular projection 41 and the axially outer end 37a of the tread rubber 37. The annular projection 41 and the shoulder blocks 42 may be made of different rubbers or may be integrally formed from the same rubber.

[0029] As shown in Figures 1 and 2, a plurality of side ridges 70 are provided on the inner side of the annular protrusion 41 in the tire radial direction and on the outer side of the sidewall 20 in the tire radial direction, spaced apart in the tire circumferential direction. The sidewall 20 has serrations 80 on the inner side of the side ridges 70 in the tire radial direction. The sidewall 20 has a smooth surface 22 on the inner side of the serrations 80 in the tire radial direction, which is aligned with the profile reference plane of the sidewall 20. The profile reference plane here refers to the surface along the profile line, which is the contour line of the sidewall 20 in the tire axial cross-section, and the tire surface of the sidewall 20 is aligned with this profile reference plane. The area near the outer surface of the sidewall 20 where the side ridges 70 are located is sometimes referred to as the buttress. Details of the plurality of side ridges 70 and serrations 80 will be described later.

[0030] As shown in Figure 1, the carcass ply 50 is stretched between a pair of beads 10. The carcass ply 50 constitutes the skeletal ply of the tire 1. The carcass ply 50 is embedded in the tire 1 in such a manner that it passes between the pair of beads 10, through a pair of sidewalls 20, a pair of shoulders 40, and the inner side of the tread 30. On the tread 30, a belt 31 is positioned radially outward of the carcass ply 50.

[0031] The carcass ply 50 includes a ply body portion 50A and a pair of winding portions 50B. The ply body portion 50A is the portion that extends from the tread 30 through each of the pair of shoulders 40 and the pair of sidewalls 20 to the inner side of each of the pair of beads 10 in the tire axial direction. The pair of winding portions 50B are the portions that are folded back radially outward from the ply body portion 50A by winding around each of the pair of bead cores 11 and extend along the sidewall 20.

[0032] The carcass ply 50 of this embodiment has a two-layer structure in which a first carcass ply 51 and a second carcass ply 52 are stacked on top of each other. In the ply body portion 50A, the first carcass ply 51 is positioned on the inner side of the tire cavity of the second carcass ply 52.

[0033] In the winding section 50B, the first carcass ply 51 is positioned on the tire axial side of the second carcass ply 52. ​​The first carcass ply 51 on the winding section 50B side extends radially outward from the tire's maximum width position 1W. The second carcass ply 52 on the winding section 50B side extends radially outward from the tire's radial side of the bead filler 12 to the area between the tire's radial side outer edge and the tire's maximum width position 1W. The portion of the second carcass ply 52 on the winding section 50B side that extends radially outward from the bead filler 12 overlaps with the second carcass ply 52 on the ply body section 50A side.

[0034] The belt 31 described above is positioned on the radially outer side of the ply body 50A. The chamfer 13 of the bead 10 described above surrounds the radially inner end of the carcass ply 50 that winds around the bead core 11.

[0035] Although the carcass ply 50 in this embodiment has a two-layer structure, the carcass ply 50 may have one layer or three or more layers. It is preferable that the carcass ply 50 be composed of two or more layers, as this sufficiently suppresses local deformation of the tire 1 near the rim mounting area.

[0036] The inner liner 60 covers the inner surface of the ply body portion 50A of the carcass ply 50 and the inner portion of the chamfer 13 in the tire axial direction, between the pair of beads 10, thereby forming the inner surface of the tire. The inner liner 60 of this embodiment has a two-layer structure. The inner liner 60 is made of air-permeable rubber and prevents air inside the tire 1 from leaking to the outside.

[0037] Here, the rubber used for the bead filler 12 is one that is at least harder than the sidewall rubber 21 and the inner liner 60. The hardness of the rubber is measured using the "Durometer hardness type A of JIS K6253-3:2012".

[0038] For example, when using the hardness of the sidewall rubber 21 as a reference, the hardness of the bead filler 12 is preferably between 1.2 and 2.3 times the hardness of the sidewall rubber 21. By setting the hardness to this extent, a balance between the flexibility of the tire and the rigidity around the bead 10 can be ensured.

[0039] The above describes the internal structure of the tire 1 according to the embodiment. Next, the multiple side ridges 70 and serrations 80 will be described.

[0040] As shown in Figure 2, the multiple side ridges 70 provided on the radially outer side of the sidewall 20 include at least three types, depending on their shape: a first side ridge 70A, a second side ridge 70B, and a third side ridge 70C. These side ridges 70A, 70B, and 70C, which are spaced apart in the circumferential direction of the tire, are all in integral contact with the peripheral wall 41b of the annular protrusion 41. Therefore, the side ridges 70 and the annular protrusion 41 are molded from the same rubber.

[0041] The protrusion height of each side ridge 70A, 70B, and 70C from the profile reference plane (tire surface) is constant and the same for all of them. In the following, when it is not necessary to distinguish between each side ridge 70A, 70B, and 70C and they can be described together, each side ridge 70A, 70B, and 70C will be collectively referred to as the side ridge 70. The maximum dimension of the side ridge 70 in the tire radial direction is preferably 10% to 30% of the tire cross-sectional height.

[0042] Figure 3 is an enlarged view of a portion of Figure 2, showing the first side ridge 70A and the second side ridge 70B and their surrounding areas. Figure 4 is a side view of the sidewall 20 showing a portion of the serration portion 80 in the tire circumferential direction. Figure 5 is a cross-sectional view of Figure 4, VV. Figure 6 is a cross-sectional view of Figure 4, VI-VI.

[0043] As shown in Figures 2 to 4, the multiple protrusions 81 constituting the serration portion 80 are curved along the profile line of the sidewall 20 and extend along the tire radial direction. The multiple protrusions 81 protrude from the smooth surface 22, which is the profile reference surface of the sidewall 20, at a certain height. The protrusion height of the multiple protrusions 81 from the smooth surface 22 is smaller than that of the side ridge portion 70. In this embodiment, the protrusion height of the protrusions 81 from the profile reference surface is, for example, about 5% to 40% of the protrusion height of the side ridge portion 70, but is not limited thereto.

[0044] The serration portion 80 is a region on the sidewall 20 that extends around the entire circumference of the tire in the tire circumferential direction, from the annular protrusion 41 to the outer edge 22a of the smooth surface 22 in the tire radial direction, excluding the side raised portion 70. As shown in Figure 1, the outer edge 22a of the smooth surface 22 in the tire radial direction is located inward in the tire radial direction from the tire's maximum width position 1W. Multiple protrusions 81 are provided throughout the entire area of ​​this serration portion 80. The outer edge 22a of the smooth surface 22 in the tire radial direction is aligned with the tire circumferential direction. Therefore, the serration portion 80 is an annular portion aligned with the tire circumferential direction having a predetermined width in the tire radial direction. It is preferable that the area occupied by the serration portion 80 on the sidewall 20 is larger than the area occupied by the side raised portion 70 on the sidewall 20. Furthermore, it is preferable that the sum of the dimensions of the serration portion 80 in the tire radial direction, regardless of its position in the tire circumferential direction, is larger than the sum of the dimensions of the side raised portion 70 in the tire radial direction.

[0045] Each side ridge 70 has a side wall 71 extending from the surface of the sidewall 20 to its own surface 72. In other words, each side ridge 70 is a flat plate-shaped ridge including a plurality of side walls 71 and a surface 72. The plurality of side walls 71 in the embodiment extend linearly in the tire radial direction, i.e., in a direction intersecting the direction in which the convex 81 extends. As shown in Figure 5, the side walls 71 are inclined. The inclination angle θ of the side walls 71 with respect to the surface 20a of the sidewall 20 is, for example, about 30° to 45°, but is not limited to this. Here, the surface 20a of the sidewall 20 is, for example, the profile reference plane of the sidewall 20. In the embodiment, at least the first side ridge 70A and the second side ridge 70B each have grooves 75 and 76 extending in the tire circumferential direction.

[0046] As shown in Figure 4, each of the multiple ridges 81 has an outer end 81a in the tire radial direction that reaches the side wall 71 of the side ridge 70. Each end 81a of the multiple ridges 81 is in integral contact with the side wall 71 of the side ridge 70 that faces inward in the tire radial direction. As shown in Figure 6, each of the ridges 81 of the embodiment arranged in the tire circumferential direction is an isosceles triangular ridge in cross-section. The angle of the vertices of the ridges 81 is, for example, about 60° to 120°, but is not limited thereto. Between the multiple ridges 81 arranged in the tire circumferential direction is a narrow flat surface 82 extending in the tire radial direction. The flat surface 82 is the same surface as the surface 20a of the sidewall 20. The pitch of the multiple ridges 81 in the tire circumferential direction, i.e., the spacing B between adjacent ridges 81, is preferably the same, and the spacing B is, for example, about 0.5 mm to 2.0 mm, but is not limited thereto. Furthermore, the cross-sectional shape of the protrusions 81 is not limited to an isosceles triangle, but may be, for example, a semicircular arc or a rectangular shape. Also, there may be no flat surface 82 between adjacent protrusions 81 in the tire circumferential direction, and the protrusions 81 may be provided continuously without interruption in the tire circumferential direction.

[0047] Because the cross-sectional shape of the protrusion 81 is an isosceles triangle, the end 81a of the protrusion 81 that integrally contacts the side wall 71 of the side ridge 70 is triangular when viewed from the side of the tire, as shown in Figure 4.

[0048] As shown in Figure 3, there is a gap between the first side ridge 70A and the second side ridge 70B in the tire circumferential and tire radial directions. There is also a gap between the second side ridge 70B and the third side ridge 70C in the tire circumferential direction. The portion between these side ridges 70 is also a serrated portion 80 provided with multiple protrusions 81. Thus, there may be a portion between adjacent side ridges 70 that is spaced in the tire circumferential direction, and this portion may have a serrated portion 80 including multiple protrusions 81 that contact the side wall 71 of the side ridge 70. Alternatively, there may be a portion between adjacent side ridges 70 that is spaced in the tire radial direction, and this portion may have a serrated portion 80 including multiple protrusions 81 that contact the side wall 71 of the side ridge 70.

[0049] The multiple protrusions 81 present between these side ridges 70 may have their outer ends in the tire radial direction integrally contacting the side wall 71 of the side ridge 70 facing the inner side in the tire radial direction, or their inner ends in the tire radial direction integrally contacting the side wall 71 of the side ridge 70 facing the outer side in the tire radial direction, and some may even be in integral contact with both the side wall 71 facing the outer side and the side wall 71 facing the inner side in the tire radial direction. Furthermore, some of the multiple protrusions 81 present between the side ridges 70 may have their outer ends in the tire radial direction integrally contacting the circumferential wall 41b of the annular protrusion 41.

[0050] Although multiple protrusions 81 are integrally in contact with the side wall 71 of the side ridge 70 in this manner, there may also be protrusions 81 that do not contact the side ridge 70 from the outer edge 22a in the tire radial direction to the annular protrusion 41, and extend until their outer ends in the tire radial direction come into integral contact with the annular protrusion.

[0051] The tire 1 of this embodiment has the above configuration. This tire 1 provides the following effects.

[0052] (1) The tire 1 according to the embodiment is a pneumatic tire having a sidewall 20, the sidewall 20 includes a side ridge portion 70 that is located on the radial side of the tire and protrudes from the sidewall 20, and the sidewall 20 has a serration portion 80 that extends substantially in the radial direction of the tire and includes a plurality of protrusions 81 that contact at least the side wall 71 of the side ridge portion 70.

[0053] In the embodiment of tire 1, the ends 81a of multiple protrusions 81 are integrally in contact with the side wall 71 facing the radially inward side of the side ridge 70. The multiple protrusions 81 support the side ridge 70 from the radially inward side of the tire, acting like spokes to suppress stress concentration and deflection at the radially inward edge of the side ridge 70. This deflection suppression effect prevents cracks from forming at the radially inward edge of the side ridge 70. In particular, tires with a large tire cross-sectional height, such as those for SUVs, or tires with a large radial length of the side ridge, are prone to deflection at the radially inward edge of the side ridge. However, with the structure of the embodiment of tire 1, the above-mentioned cracks are effectively suppressed even in such tires, and they can withstand harsh driving environments.

[0054] In the tire 1 according to this embodiment, the outer end of the ridge 81 in the radial direction of the tire is in integral contact with the annular protrusion 41. As a result, the ridge 81 prevents stress from concentrating and causing deflection at the boundary between the annular protrusion 41 and the sidewall 20, thereby suppressing crack formation in this area.

[0055] In the tire 1 according to this embodiment, the side wall 71 of the side ridge portion 70, which is in contact with the plurality of protrusions 81, is inclined with respect to the surface 20a of the sidewall 20. This further suppresses stress concentration and deflection at the boundary between the side ridge portion 70 and the sidewall 20, thereby suppressing crack formation in this area.

[0056] In the embodiment, the tire 1 has a portion between adjacent side ridges 70 that is spaced apart in the circumferential direction of the tire, and this portion may have a serration portion 80 that includes a plurality of protrusions 81 that contact the side wall 71 of the side ridge 70. This further suppresses stress concentration and deflection at the boundary between the side ridge 70 and the sidewall 20, thereby suppressing crack formation in this portion.

[0057] In the embodiment, the tire 1 has a portion between adjacent side ridges 70 that is spaced apart in the radial direction of the tire, and this portion may have a serration portion 80 including a plurality of protrusions 81 that contact the side wall 71 of the side ridge 70. This further suppresses stress concentration and deflection at the boundary between the side ridge 70 and the sidewall 20, thereby suppressing crack formation in this portion.

[0058] (2) In the tire 1 according to the embodiment described in (1), the sidewall 20 has a smooth surface 22 along the surface 20a of the sidewall 20 on the inner side of the serration portion 80 in the tire radial direction, and the ridges 81 have a height that protrudes more than the smooth surface 22.

[0059] Because the protrusions 81 are higher than the smooth surface 22, the aforementioned deflection suppression effect is more reliably achieved, and the occurrence of cracks on the inner edge of the side ridge portion 70 in the tire radial direction is suppressed.

[0060] (3) In the tire 1 according to the embodiments of (1) and (2) above, it is preferable that the area occupied by the serration portion 80 on the sidewall 20 is larger than the area occupied by the side ridge portion 70 on the sidewall 20.

[0061] This makes it easier for the aforementioned deflection suppression effect to be reliably achieved, and prevents cracks from forming on the inner edge of the side ridge portion 70 in the tire radial direction.

[0062] (4) In the tire 1 according to the embodiment described in (1) to (3) above, it is preferable that the maximum dimension of the side ridge portion 70 in the tire radial direction is 10% or more and 30% or less of the tire cross-sectional height.

[0063] This makes it easier for the aforementioned deflection suppression effect to be reliably achieved, and prevents cracks from forming on the inner edge of the side ridge portion 70 in the tire radial direction.

[0064] (5) In the tire 1 according to the embodiment described in (1) to (4) above, it is preferable that the sum of the dimensions of the serration portion 80 in the tire radial direction is greater than the sum of the dimensions of the side ridge portion 70 in the tire radial direction, regardless of the position in the tire circumferential direction.

[0065] This makes it easier for the aforementioned deflection suppression effect to be reliably achieved, and prevents cracks from forming on the inner edge of the side ridge portion 70 in the tire radial direction.

[0066] Furthermore, the present invention is not limited to the embodiments described above, and modifications, improvements, etc., made to the extent that the objectives of the present invention can be achieved are also included within the scope of the present invention.

[0067] For example, although the protrusion 81 is provided in a state where it is integrally in contact with the side wall 71 of the side ridge 70, the protrusion 81 and the side ridge 70 may be made of different rubber and be in contact with each other. [Explanation of symbols]

[0068] 1. Tire (pneumatic tire) 20 Sidewall 20a Sidewall surface 22 Smooth surface 70 Side elevation 71 Side wall of the side elevation 80 Serrated section 81 Convex Strip X Tire Axle Y Tire radial direction

Claims

1. A pneumatic tire with a sidewall, The sidewall includes a side ridge portion that is positioned on the radially outer side of the tire and protrudes from the sidewall, A pneumatic tire wherein the sidewall has a serrated portion that extends substantially in the radial direction of the tire and includes a plurality of protrusions that contact at least the side wall of the side ridge.

2. The pneumatic tire according to claim 1, wherein the sidewall has a smooth surface along the surface of the sidewall on the radially inward side of the serration portion, and the protrusions have a height that protrudes above the smooth surface.

3. The pneumatic tire according to claim 1 or 2, wherein the area occupied by the serration portion on the sidewall is larger than the area occupied by the side ridge portion on the sidewall.

4. The pneumatic tire according to claim 1 or 2, wherein the maximum dimension of the side ridge in the tire radial direction is 10% or more and 30% or less of the tire cross-sectional height.

5. The pneumatic tire according to claim 1 or 2, wherein, at any position in the circumferential direction of the tire, the sum of the dimensions of the serration portions in the radial direction of the tire is greater than the sum of the dimensions of the side ridge portions in the radial direction of the tire.

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