JP5232580B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire, and more particularly, to a pneumatic tire that improves the durability of a peripheral portion of a mark while maintaining the visibility of a mark such as letters and numbers provided on a sidewall portion.

  In general, a plurality of marks made of letters, numbers, symbols, figures, or the like are provided on the sidewall portion of the pneumatic tire along the tire circumferential direction. The side wall portion swings and deforms in the tire width direction around the bead portion when the vehicle travels, and repeatedly receives a large distortion, so the vicinity of the circumferential side extending in the tire circumferential direction among the sides constituting the mark Cracks easily occur.

Therefore, cracks are suppressed by forming the curvature R of the character base that forms the contour of the circumferential side large (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2005-297866 (Page 4, FIGS. 1 and 2)

 However, in the conventional technology described above, since the size of the mark is small in the pneumatic tire having a small outer diameter, the interval between the circumferential sides is also reduced, and the character bottom of the circumferential side facing the tire radial direction is reduced. There is a problem that it is difficult to set the curvature R large.

 Therefore, the present invention has been made in view of such a situation, even in a small-diameter tire, while maintaining the visibility of marks such as letters and numbers provided on the sidewall portion, It aims at providing the pneumatic tire which improves the durability of a peripheral part.

 In order to solve the above-described problems, the present invention has the following features.

 First, in the first feature of the present invention, a mark (mark 20) having a plurality of circumferential sides (circumferential sides 21 to 24) extending in the tire circumferential direction is provided on the sidewall portion (sidewall portion 15). Surface of a belt-like portion (band-like portions 25 and 26) disposed between two opposite sides of the pneumatic tire (pneumatic tire 1) that is spaced apart and opposed in the tire radial direction among a plurality of circumferential sides The height is higher than the sidewall surface (bottom portion 28a) around the mark, and lower than the surface height of the contour portion (contour portion 27) of the mark.

  As a result, the rigidity in the vicinity of the mark such as a character provided on the sidewall portion is improved, and cracks caused by the deflection deformation received by the sidewall portion during traveling of the vehicle can be effectively suppressed.

  In other words, when the vehicle is running, the sidewall of the tire is deformed by the load repeatedly received from the road surface.Therefore, if a mark such as a character is displayed on the sidewall, there is a risk that a crack may occur from around the mark. is there. Therefore, by forming the corners of the outline of the mark round and setting a so-called curvature R large, stress concentration can be suppressed and crack prevention can be achieved. However, it is difficult to set a large curvature R at the corners of the belt-like portions between the circumferential sides along the tire circumferential direction because the interval in the tire radial direction is narrow.

 Therefore, as in the invention of the present application, a band-shaped portion is arranged between the contour portion of the mark and the surface of the sidewall portion, and the surface of the band-shaped portion is raised so that it is higher than the surface of the sidewall portion around the mark. By arranging it high, the height difference between the contour portion of the mark and the surface of the sidewall portion can be reduced, the rigidity in the vicinity of the mark can be improved, and the occurrence of cracks can be effectively suppressed.

  In other features, a pneumatic tire (air) in which a mark (mark 20) having a circumferential side (circumferential side 36) extending in the tire circumferential direction is provided on the surface of the sidewall (sidewall 15). On the surface of the vicinity of the intersection (intersection vicinity 38, 39) between the circumferential side (circumferential side 36) and the radial side (radial side 37) intersecting the circumferential side. The height is higher than the sidewall surface (bottom portion 28a) around the mark, and lower than the surface height of the contour portion (contour portion 27) of the mark.

 Also in this case, the vicinity of the intersection is arranged between the outline of the mark and the surface of the sidewall, and the surface of the vicinity of the intersection is raised to be higher than the surface of the sidewall around the mark. By doing so, the height difference between the contour portion of the mark and the surface of the sidewall portion can be reduced, the rigidity in the vicinity of the mark can be improved, and cracks can be effectively suppressed.

  In other features, the height of the belt-shaped portion (band-shaped portion height H1) from the surface of the sidewall portion around the mark (mark 20) to the surface of the belt-shaped portions (band-shaped portions 25 and 26), and the mark The height of the vicinity of the intersection from the surface of the sidewall portion to the surface of the vicinity of the intersection (intersection vicinity height H3) is the contour portion from the sidewall surface to the surface of the contour portion of the mark around the mark. It is set to 1/2 to 2/3 of the height (contour height H2, H4).

  In other features, a plurality of first ridges (upper first ridge 28, lower first ridge 29) are continuously formed around the mark (mark 20), and a belt-like portion (band-like portion 25). , 26) and the surface of the vicinity of the intersection (intersection vicinity portions 38, 39) are formed at substantially the same height as the top of the first ridge (top 28b).

  In other features, the belt-like portions (band-like portions 25 and 26) and the vicinity of the intersection (intersection vicinity portions 38 and 39) are provided with a first ridge (upper first ridge) provided around the mark (the mark 20). 28, a plurality of second ridges (second ridges 42) having lower undulation heights (undulation heights h2) in the tire width direction than the lower first ridges 29) are continuously formed. The two ridges are extended with an angle of 0 ° to 45 ° with respect to the tire radial direction.

  According to the present invention, there is provided a pneumatic tire that improves the durability of the peripheral portion of the mark while maintaining the visibility of the mark such as letters and numbers provided on the sidewall portion even in a small-diameter tire. can do.

  Next, an embodiment of a pneumatic tire according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[First embodiment]
First, a first embodiment of the present invention will be described.

  FIG. 1 is a cross-sectional view in the tire width direction showing a pneumatic tire according to the present invention.

  As shown in FIG. 1, on the inner peripheral side of the annularly formed pneumatic tire 1, bead cores 2, 2 that are arranged to be opposed to each other in the tire width direction, and the outer side in the tire radial direction of the bead cores 2, 2. A pair of bead portions 4, 4 including bead fillers 3, 3 disposed in a pair is provided.

  Further, the pneumatic tire 1 according to the present embodiment is provided with a carcass 5 made of a carcass cord and rubber and connecting the pair of bead portions 4, 4. The carcass 5 includes a main body 6 that connects the pair of bead cores 2 and 2 in a toroidal shape toward the outer side in the tire radial direction, and the circumference of the bead core 2 is wound from the inner side to the outer side in the tire width direction. It is comprised from the folding | returning part 7 extended toward an outer side. An inner liner 8 made of highly airtight rubber corresponding to a tube is provided inside the carcass 5 in the tire width direction.

  Further, a belt layer 10 formed in a belt shape along the circumferential direction is formed in the vicinity of the top of the main body 6 of the carcass 5. The belt layer 10 includes a first belt layer 11 coupled on the body portion 6 of the carcass 5 and a second belt layer 12 disposed on the outer side in the tire radial direction of the first belt layer 11. , Has a function of reinforcing a tread portion 13 to be described later.

  On the outer side in the tire radial direction of the second belt layer 12, a tread portion 13 that comes into contact with the road surface when the pneumatic tire 1 rotates, and a pair of shoulder portions 14, 14 disposed on both sides in the tire width direction of the tread portion 13 and Sidewall portions 15 and 15 are provided. A plurality of grooves 16 called tread patterns are formed on the surface of the tread portion 13, and these grooves 16 have a function of discharging water that has entered between the tread portion 13 and the road surface and preventing slippage. . In FIG. 1, reference sign CL indicates a tire equator line.

  FIG. 2 is a front view of a mark according to the first embodiment of the present invention.

  The alphabet E which is the mark 20 shown in FIG. 2 is formed on the surface of the sidewall portion 15 shown in FIG. In this specification, a mark is comprised from a character, a number, a figure, a symbol, etc., and as shown in FIG. 2 in 1st Embodiment, the circumferential direction side 21 extended along a tire circumferential direction is tire radial direction. Three of them are extended substantially in parallel at a predetermined interval. Specifically, the circumferential side 21 in FIG. 2 includes an outer circumferential side 22 disposed on the outermost side in the tire radial direction, an inner circumferential side 23 disposed on the innermost side in the tire radial direction, and outer circumferential sides thereof. It consists of an intermediate circumferential side 24 formed between the direction side 22 and the inner circumferential side 23.

  Both the outer circumferential side 22 and the intermediate circumferential side 24 extend along the tire circumferential direction and are arranged to face each other. Further, both the inner circumferential side 23 and the intermediate circumferential side 24 extend along the tire circumferential direction and are arranged to face each other. Between the outer circumferential side 22 and the intermediate circumferential side 24 and between the inner circumferential side 23 and the intermediate circumferential side 24, belt-like portions 25 and 26 extending in the tire circumferential direction are formed, respectively. . In FIGS. 2, 4, 5 and 6, these portions are indicated by point hatching in order to clarify the band-like portion and the vicinity of the intersection described later.

  A contour portion 27 that clearly recognizes the letter E is formed in the contour portion of the mark 20. Further, first ridges 28 and 29 are formed around the mark 20. The first ridge is composed of an upper first ridge 28 disposed on the outer side in the tire radial direction from the inner circumferential side and a lower first ridge 29 disposed on the inner side in the tire radial direction. The upper first ridge 28 extends along the tire radial direction, that is, at an angle of about 0 ° with respect to the tire radial direction. The lower first ridge 29 extends obliquely at an angle of about 45 ° with respect to the tire radial direction.

  FIG. 3 is an enlarged cross-sectional view taken along line AA in FIG.

  As shown in FIG. 3, the contour portion 27 around the mark is formed one step higher than the inner main body portion 30, and is continuously formed over the entire circumference of the mark 20. Further, the height of the surface 25a of the belt-like portion 25 formed between the outer circumferential side 22 and the intermediate circumferential side 24 and extending in the tire circumferential direction is the bottom 28a ( The height of the belt-shaped portion (the height of the bottom) from the bottom 28a of the upper first ridge 28 to the surface 25a of the belt-shaped portion 25 is set to H1. On the other hand, the height of the surface 25a of the band 25 is lower than the surface 27a of the contour 27, and the height of the contour from the bottom 28a (side wall surface) of the upper first ridge 28 to the surface 27a of the contour 27 ( The character height is set to H2.

  In the present embodiment, the first ridge 28 is formed around the mark 20, but the first ridge 28 is not necessarily formed. When the first ridge 28 is not formed, the height around the mark is the height of the sidewall surface.

  Further, as shown in FIG. 3, the band height H1 from the bottom 28 a of the upper first ridge 28 to the surface 25 a of the band 25 is from the bottom 28 a (side wall surface) of the upper first ridge 28 to the contour 27. Is set to 1/2 to 2/3 of the contour height H2 up to the surface 27a.

  Further, the surface 25 a of the belt-like portion 25 is formed substantially the same as the height of the top portion 28 b of the upper first ridge 28.

  4 and 5 are front views showing examples of other marks according to the first embodiment of the present invention.

  In FIG. 2, the alphabet E is shown as the mark 20, but other than this, the present invention can be applied to, for example, the alphabet G and S.

  In the case of G, as shown in FIG. 4, on the right side of the character, a portion sandwiched between two circumferential sides 31 and 32 that are spaced apart from each other vertically is a belt-like portion 33 (a portion indicated by dot hatching). It is. Here, since the elongate part arrange | positioned at the center part of a tire circumferential direction and extended in a tire radial direction is not set to the strip | belt-shaped part 33, the reduction | decrease in the visibility of the mark 20 can be suppressed. In the case of S, as shown in FIG. 5, the portions formed at the lower left and upper right are the belt-like portions 34 and 35 (portions indicated by dot hatching). Also in these belt-like portions 34 and 35, the dimensional relationship such as the surface height of the belt-like portions 34 and 35 is set in the same manner as described with reference to FIGS.

<Action / Effect>
In the present embodiment, the pneumatic tire 1 is provided with a mark 20 having a plurality of circumferential sides 21 to 24 extending in the tire circumferential direction on the sidewall portion 15, and the plurality of circumferential sides 21 to 24. The surface height of the band-like portions 25 and 26 disposed between the two sides 22, 23 and 24 which are spaced apart from each other in the tire radial direction is higher than the sidewall portion surface 28 a around the mark 20. It is formed lower than the surface height of the contour portion 27 of the mark 20.

  As a result, the rigidity in the vicinity of the mark 20 such as characters provided on the sidewall portion 15 is improved, and cracks caused by the deflection deformation received by the sidewall portion 15 during traveling of the vehicle can be effectively suppressed. .

  That is, when the vehicle travels, the tire sidewall portion 15 is deformed by a load repeatedly received from the road surface. Therefore, when a mark 20 such as a character is displayed on the sidewall portion 15, a crack is generated from around the mark 20. May occur. Therefore, by forming the corners of the contour portion 27 of the mark 20 round and setting a so-called curvature R large, stress concentration can be suppressed and crack prevention can be achieved. However, the belt-like portions 25 and 26 of the circumferential sides 22 to 24 along the tire circumferential direction have a narrow interval in the tire radial direction, so it is difficult to set the corner curvature R large.

 Therefore, as in the present invention, the band portions 25 and 26 are disposed between the contour portion 27 of the mark 20 and the surface of the sidewall portion, and the surfaces of the band portions 25 and 26 are raised to raise the mark 20. The height difference between the contour part 27 of the mark 20 and the surface of the side wall part is reduced by arranging it higher than the surface of the side wall part in the periphery of the mark, and the rigidity in the vicinity of the mark 20 is improved and cracks are generated. It can be effectively suppressed. Moreover, in this embodiment, when the width | variety of the radial direction of the strip | belt-shaped parts 25 and 26 is 2 mm or less, the effect of crack prevention becomes high.

  The height H1 of the belt-like portion from the surface of the sidewall portion around the mark 20 to the surface of the belt-like portions 25 and 26 is determined from the surface of the sidewall portion around the mark 20 of the contour portion 27 of the mark 20. It is set to 1/2 to 2/3 of the contour heights H2 and H4 to the surface.

  Here, if the belt-like portion height H1 is less than ½ of the contour portion heights H2 and H4, it becomes difficult to effectively prevent cracks due to improved rigidity. Further, if it is set to be larger than 2/3, there is a problem that the visibility of the mark 20 is lowered. Therefore, the mark is set by setting H1 within a range of 1/2 to 2/3 of H2 and H4. Thus, cracks can be effectively prevented while maintaining the visibility of 20 high.

  A plurality of upper first ridges 28 and lower first ridges 29, which are first ridges, are continuously formed around the mark 20, and the surfaces of the strips 25 and 26 are formed on the first ridges. Since it is formed at substantially the same height position as the top portion 28b, it is possible to reduce the man-hours for forming the mark 20 on the sidewall portion 15.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. However, the same or similar parts as those in the first embodiment described above are denoted by the same reference numerals and the description thereof is omitted.

  FIG. 6 is a front view of a mark according to the second embodiment of the present invention, and FIG. 7 is an enlarged sectional view taken along line BB in FIG.

  The mark 20 according to the present embodiment is an alphabet T, and is arranged on the upper side (tire radial direction outer side) and extends in the tire circumferential direction and on the lower side (tire radial direction inner side). It comprises a radial side 37 extending in the radial direction.

  As shown in FIG. 6, the circumferential side 36 and the radial side 37 intersect with each other, and the intersection vicinity portions 38 and 39 are formed in a substantially triangular shape. Similarly to the first embodiment, an upper first ridge 28 and a lower first ridge 29 are formed around the mark 20.

  As shown in FIG. 7, the height of the surface 38 a of the intersection vicinity portion 38 is higher than the bottom portion 28 a (side wall surface) of the surrounding upper first ridge 28, and from the bottom portion 28 a of the upper first ridge 28 to the intersection vicinity portion 38. The height in the vicinity of the intersection (bottom raising height) to the surface 38a is set to H3. On the other hand, the height of the surface 38a of the intersection vicinity portion 38 is lower than the surface 27a of the contour portion 27, and the height of the contour portion from the bottom portion 28a (side wall surface) of the upper first ridge 28 to the surface 27a of the contour portion 27. (Character height) is set to H4.

In the present embodiment, the first ridge 28 is formed around the mark 20, but the first ridge 28 is not necessarily formed. When the first ridge 28 is not formed, the height around the mark is the height of the sidewall surface.

  Further, as shown in FIG. 7, the height H3 in the vicinity of the intersection from the bottom 28a of the upper first ridge 28 to the surface 38a of the vicinity 38 of the intersection is contoured from the bottom 28a (surface of the sidewall) of the upper first ridge 28. It is set to 1/2 to 2/3 of the contour height H4 to the surface 27a of the portion 27.

  Further, the surface 38 a of the intersection vicinity portion 38 is formed to be substantially the same as the height of the top portion 28 b of the upper first ridge 28.

<Action / Effect>
In the present embodiment, the pneumatic tire 1 is provided with a mark 20 having a circumferential side 36 extending in the tire circumferential direction on the surface of the sidewall portion 15, and includes the circumferential side 36 and the circumferential side. The height of the surfaces of the intersection neighboring portions 38 and 39 with the radial side 37 intersecting 36 is higher than the sidewall surface (bottom portion 28 a) around the mark 20, and the surface of the contour portion 27 of the mark 20. It is formed lower than the height.

 Also in this case, the vicinity of the intersection 20 is disposed between the contour portion 27 of the mark 20 and the surface of the sidewall, and the surface of the vicinity of the intersection 38, 39 is raised to the periphery of the mark 20. The height difference between the contour part 27 of the mark 20 and the surface of the side wall part is reduced by arranging it higher than the surface of the side wall part at the surface, and the rigidity in the vicinity of the mark 20 is improved, thereby effectively generating cracks. Can be suppressed.

  The intersection vicinity height H3 from the surface of the sidewall portion around the mark 20 to the surface of the intersection vicinity portions 38 and 39 is the contour portion of the mark 20 from the surface of the sidewall portion around the mark 20. 27 to 2/3 of the contour heights H2 and H4 up to the surface of 27. Here, if the intersection vicinity height H3 is less than ½ of the contour heights H2 and H4, it is not possible to effectively prevent cracks due to improved rigidity. Further, if it is set to be larger than 2/3, there is a problem that the visibility of the mark 20 is lowered. Therefore, the mark is set by setting H3 within a range of 1/2 to 2/3 of H2 and H4. It is possible to prevent cracks while maintaining the visibility of 20 high.

  Further, since the surfaces of the intersection vicinity portions 38 and 39 are formed at substantially the same height as the top portion 28b of the first ridge, the number of man-hours for forming the mark 20 on the sidewall portion 15 is reduced. Can be reduced.

[Third embodiment]
Next, a third embodiment of the present invention will be described. However, parts that are the same as or similar to those in the first and second embodiments described above are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 8 is a front view of a mark according to the third embodiment of the present invention, and FIG. 9 is an enlarged sectional view taken along the line CC of FIG.

 In the third embodiment, in addition to the second embodiment, a plurality of second ridges 42 are formed in the intersection vicinity portions 40 and 41. As shown in FIG. 8, the second ridge 42 is formed along the tire radial direction. However, in this invention, it is not limited to the same as a tire radial direction, It should just extend at an angle of 0 degree-45 degrees with respect to a tire radial direction. If the extending direction of the second ridge 42 is the same direction as the extending direction of the surrounding first ridges 28 (that is, the angle with respect to the tire radial direction is 0 °), the appearance is improved. preferable.

  As shown in FIG. 9, the undulation height h2 in the tire width direction of the second ridge 42 formed in the intersection vicinity portions 40, 41 is set lower than the undulation height h1 in the tire width direction of the first ridge 28. Yes.

  The height of the top portion 42a of the second ridge 42 is the same as the height of the top portion 28b of the first ridge.

<Action / Effect>
In the present embodiment, the intersection ridges 38 and 39 have a second ridge having a height lower than that of the upper first ridge 28 and the lower first ridge 29 which are the first ridges provided around the mark 20. 42 are continuously formed, and both the first ridges 28 and 29 and the second ridge 42 extend at an angle of 0 ° to 45 ° with respect to the tire radial direction. Therefore, it is possible to efficiently suppress a decrease in the visibility of the mark 20.

<Other embodiments>
As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the pneumatic tire 1 has been described using a general radial tire including the bead portion 4 and the belt layer 10 as an example, but a bias tire other than the radial tire may be used.

 As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is determined only by the invention specifying matters according to the scope of claims reasonable from the above description.

 Next, in order to clarify the effects of the present invention, test results performed using the pneumatic tires according to Examples 1 to 3 and Comparative Examples 1 and 2 will be described.

As the test tires according to Examples 1 to 3 and Comparative Examples 1 and 2, tires having a tire size of 165 / 55R15 were used. Characters are displayed along the tire circumferential direction on the test tire, and a ridge is provided around the character, and the height of the character is 0.6 mm from the bottom surface of the ridge. The test tire was assembled on a rim having a wheel size of 4.5 J × 15, and the tire was filled with air so that the internal pressure was 130 kPa. When a load of 390 kg is applied in an ambient temperature of 38 ± 3 ° C, set in a low internal pressure long gland ram type drum tester and run at a speed of 60 km / h, and a crack occurs in the mark part (character part) It was evaluated by the mileage. Moreover, the inspector judged the visibility of a character favorable and insufficient by visual observation.

  As a result, as shown in Table 1, the drum running index is significantly improved in Examples 2 and 3 in which the height of the bottom is set to 0.4 mm or 0.5 mm as compared with Comparative Example 1 in which the bottom is not raised. did. Moreover, it turned out that the visibility of a character improves the direction of Examples 1 and 2 with respect to the comparative example 2 which raised the whole area | region inside a character.

It is sectional drawing of the tire width direction which shows the pneumatic tire which concerns on this invention. It is a front view of the mark by a 1st embodiment of the present invention. It is an expanded sectional view by the AA line of FIG. It is a front view which shows the example of the other mark by 1st Embodiment of this invention. It is a front view which shows the example of the other mark by 1st Embodiment of this invention. It is a front view of the mark by 2nd Embodiment of this invention. It is an expanded sectional view by the BB line of FIG. It is a front view of the mark by 3rd Embodiment of this invention. It is an expanded sectional view by the CC line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 15 ... Side wall part 20 ... Mark 21-24, 31, 32, 36 ... Circumferential side 25, 26 ... Band-shaped part 27 ... Contour part 28, 29 ... 1st ridge 28a ... Bottom part (side wall part surface)
28b ... Top 33, 34, 35 ... Band-like part 37 ... Radial side 38, 39 ... Intersection vicinity 40, 41 ... Intersection vicinity 42 ... Second ridge 42a ... Top

Claims (5)

A pneumatic tire provided with a mark having a plurality of circumferential sides extending in the tire circumferential direction on the sidewall portion,
The surface height of the belt-like portion disposed between two opposite sides spaced apart in the tire radial direction among the plurality of circumferential sides is higher than the sidewall portion surface around the mark, and the mark A pneumatic tire characterized in that it is formed lower than the surface height of the contour portion. A pneumatic tire provided with a mark having a circumferential side extending in the tire circumferential direction on the surface of the sidewall portion,
The height of the surface in the vicinity of the intersection of the circumferential side and the radial side that intersects the circumferential side is higher than the surface of the sidewall around the mark, and the surface height of the contour of the mark A pneumatic tire characterized by being formed lower than the above. The height of the belt-like portion from the surface of the sidewall portion around the mark to the surface of the belt-like portion, and the height of the vicinity of the intersection from the surface of the sidewall portion around the mark to the surface of the intersection portion Well,
3. The height of the contour portion from the surface of the sidewall portion around the mark to the surface of the contour portion of the mark is set to 1/2 to 2/3. Pneumatic tire described in 2. A plurality of first ridges are continuously formed around the mark,
The surface of the belt-shaped portion and the surface of the vicinity of the intersection are both formed at substantially the same height position as the top portion of the first ridge. Pneumatic tire described in 2. A plurality of second ridges having a lower undulation height in the tire width direction than the first ridge provided around the mark are continuously formed in the belt-like portion and the vicinity of the intersection,
The pneumatic tire according to claim 4, wherein the first ridge and the second ridge are extended at an angle of 0 ° to 45 ° with respect to a tire radial direction.

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