JP2012218511A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of improving the abrasion service life and tire durability in a well-balanced state.SOLUTION: This pneumatic tire 100 includes a plurality of grooves 11-16 for partitioning and forming blocks 20 being tread land parts in a tread part 10. The pneumatic tire includes a plurality of long hole-shaped recessed parts 40 provided on at least one sidewall surface 30 of grooves 11A and 14 at least a part of the plurality of grooves, extending in the groove extending direction of these grooves and terminating in a sidewall surface at least one end of both end parts in the longitudinal direction. One long hole-shaped recessed part has an overlapping part 60 overlapping with the other long hole-shaped recessed part in a position in the groove extending direction.

Description

  The present invention relates to a pneumatic tire. The present invention particularly relates to a pneumatic tire capable of improving the wear life and tire durability in a well-balanced manner.

  A pneumatic tire having a tread pattern in which a plurality of rows of rib-like land portions are defined by a plurality of circumferential grooves is known. There is also known a pneumatic tire having a block-based tread pattern in which a plurality of block land portions are defined by a plurality of circumferential grooves and width grooves.

  The wear amount in the tread land portion such as the rib land portion or the block land portion can be expressed by the product of the shear force acting on each tread land portion and the slip amount in each block. And the shear force which acts on a block with high shear rigidity is large, and the shear force which acts on a block with low shear rigidity becomes small. For this reason, in order to prolong the wear life of the tire, it is effective to lower the shear rigidity in each tread land portion and lower the wear energy in each tread land portion.

  Here, the following are known as pneumatic tires in which recesses such as depressions and cutouts are formed on the groove wall surface of the groove formed in the tread portion. Patent Document 1 describes a tire in which a large number of holes or convex lines or concave lines parallel to the tire surface are provided on a groove wall surface of a groove formed in a tread portion to improve drainage. Further, Patent Document 2 describes a tire in which a plurality of depressions are formed in the middle part in the groove depth direction of the wall surface of the groove that defines the block land portion (Claim 3, FIGS. 10 to 13). . In this tire, the number of dents formed at the same position in the groove forming direction is reduced as the distance from the vicinity of the corner of the block land portion decreases, thereby making the contact pressure of the block uniform and uneven wear in the block. It is described that can be suppressed.

JP-A-3-57704 JP 2005-193702 A

  If a concave portion is provided on the wall surface of the groove forming the tread land portion as in Patent Document 1 and Patent Document 2, when a shearing force is applied to the tread land portion during load rolling of the tire, the concave portion is crushed and the tread land Since the part can fall down, the shear rigidity of the tread land part decreases. Therefore, this method is effective for reducing the wear energy in the tread land portion and extending the wear life of the tire.

  However, Patent Document 1 and Patent Document 2 have the following problems. First, when a recess is provided in the groove wall, the rigidity of the tread land portion is lowered, while a crack starting from the recess tends to occur in the tread land portion. Here, when a concave line is provided on the groove wall surface as in Patent Document 1, a crack generated at one portion of the concave portion tends to spread in the direction of the concave line. Further, when a large number of circular holes are provided in the groove wall as in Patent Documents 1 and 2, cracks generated in the hole portion propagate to adjacent holes, and the crack is likely to spread over a wide range of the groove wall. For this reason, there is a problem that the durability of the tire cannot be sufficiently obtained due to cracks.

  Furthermore, Patent Document 1 and Patent Document 2 do not have a recess in the groove wall for the purpose of reducing the wear energy of the tread land portion. For this reason, there is room for optimization from the viewpoint of lowering the wear energy in the tread land portion and extending the wear life of the tire. For example, if the location where the recess is formed and the location where the recess is not formed depending on the position in the groove extending direction, the shear rigidity of the tread land portion partitioned by this groove cannot be reduced uniformly, and as a result, wear The amount cannot be reduced sufficiently.

  Then, in view of the said subject, this invention aims at providing the pneumatic tire which can improve a wear life and tire durability in good balance.

  As a result of intensive studies by the present inventors, it has been found that the above-mentioned object can be achieved by optimizing the shape and arrangement of the recesses provided on the wall surfaces of the grooves that define the tread land portion, and the present invention has been completed. It came to do.

  That is, in view of the above problems, the gist of the present invention is as follows. The pneumatic tire of the present invention is a pneumatic tire having a plurality of grooves in the tread portion that define and form a tread land portion on at least one side wall surface of at least some of the plurality of grooves. The groove has a plurality of slot-like recesses extending in the groove extending direction and at least one end of the both ends in the longitudinal direction terminating in the side wall surface, and the one slot-like recess is positioned in the groove extending direction. In the present invention, it has an overlapping portion overlapping with the other elongated hole-shaped recess.

  Further, in the pneumatic tire of the present invention, with respect to the groove having the long hole-shaped concave portion, the ratio of the dimension occupied by the long hole-shaped concave portion to the shortest distance along the side wall surface from the tread surface to the groove bottom is The groove is preferably the same at a position of 60% or more of the groove extending direction distance.

  Furthermore, it is preferable that the pneumatic tire of the present invention has a tread wear indicator, and at least a part of the plurality of elongated hole-shaped recesses has a lower end at the same groove depth position as the upper end of the tread wear indicator.

  According to the present invention, the concave portion provided on the groove sidewall surface has a long hole shape extending in the groove extending direction and terminating at the end in the groove sidewall surface. It becomes difficult to propagate to. In addition, since the plurality of long hole-shaped concave portions are arranged so as to overlap each other at the position in the groove extending direction, the shear rigidity in the tread land portion can be uniformly reduced. Therefore, according to the pneumatic tire of the present invention, it is possible to improve the wear life and the tire durability in a balanced manner.

It is an expanded view which shows a part of tread part 10 of the pneumatic tire 100 according to this invention. 3 is an enlarged perspective view of a first block 20 of the pneumatic tire 100. FIG. (A) is II sectional drawing of FIG. 1, (b) is II-II sectional drawing of FIG. It is the figure which extracted only the long hole-shaped recessed part from the front view of the side wall surface 30 of the block land part 20, and showed the arrangement | positioning relationship of long hole-shaped recessed part 40A, 40B. It is the figure which showed the arrangement | positioning relationship of the slot-shaped recessed part 80 provided in the side wall surface of the groove | channel in another pneumatic tire according to this invention. It is the figure which showed the arrangement | positioning relationship of the slot-shaped recessed part 85 provided in the side wall surface of the groove | channel in another pneumatic tire according to this invention. It is the figure which showed the arrangement | positioning relationship of the slot-shaped recessed part 90 provided in the side wall surface of the groove | channel in another pneumatic tire according to this invention.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. In principle, the same components are denoted by the same reference numerals, and description thereof is omitted.

(Embodiment 1)
A pneumatic tire 100 (hereinafter also simply referred to as “tire 100”), which is an embodiment of the present invention, will be described with reference to FIGS.

  The pneumatic tire of the present invention has a plurality of grooves in the tread portion that define the tread land portion. In the tire 100 of this embodiment shown in FIG. 1, six circumferential grooves 11 </ b> A, 11 </ b> B, 12 </ b> A, 12 </ b> B, 13 </ b> A, 13 </ b> B extending along the tire circumferential direction are disposed in the tread portion 10. Further, in the tire 100, a plurality of widthwise grooves 14, 15A, 15B, 16A, and 16B extending along the tire width direction are arranged in the tread portion 10 at equal intervals in the tire circumferential direction. The first circumferential grooves 11A and 11B, the second circumferential grooves 12A and 12B, and the third circumferential grooves 13A and 13B are arranged symmetrically with respect to the tire equator CL, respectively. These circumferential grooves are all linear and parallel to the tire circumferential direction, and have the same groove width and groove depth. Moreover, these width direction grooves also have the same groove width and groove depth. Moreover, the groove depth of these circumferential grooves and the groove depth of the width direction grooves are equal.

  A plurality of first blocks 20 that are tread land portions are defined by the first circumferential grooves 11A and 11B and the first width direction grooves 14. The first circumferential grooves 11A and 11B, the second circumferential grooves 12A and 12B, and the second width grooves 15A and 15B define a plurality of second blocks 21A and 21B as tread land portions, respectively. . The second circumferential grooves 12A and 12B, the third circumferential grooves 13A and 13B, and the third width grooves 16A and 16B define a plurality of third blocks 22A and 22B as tread land portions, respectively. . Further, rib-shaped land portions 23A and 23B as tread land portions are partitioned by the third circumferential grooves 13A and 13B and the tread ends E. About the 1st-3rd block, the adjacent block row | line | column is mutually arrange | positioned with a phase difference in the half pitch tire circumferential direction.

  The circumferential grooves 11A, 11B, 12A, 12B, 13A, and 13B and the widthwise grooves 14, 15A, 15B, 16A, and 16B of the tire 100 extend on the side wall surfaces on both sides in the extending direction of the respective grooves. A plurality of elongated hole-shaped recesses are provided. With reference to FIG. 2, FIG. 3 (a), (b) and FIG. 4, the 1st block 20 is demonstrated as a representative. As shown in FIG. 2 and FIG. 3A, a plurality of elongated recesses 40 extending in the extending direction of the groove 11 </ b> A are formed on the side wall surface 30 of the first circumferential groove 11 </ b> A that defines the first block 20. Provided. Further, as shown in FIGS. 2 and 3B, the side wall surface 32 of the first width direction groove 14 that similarly defines the first block 20 has a plurality of elongated holes extending in the extending direction of the groove 14. A recess 45 is provided. 3A and 3B, the groove bottoms 50 and 51 of the grooves 11A and 14 are indicated by broken lines, respectively.

  The elongated hole-shaped recess will be further described with reference to FIGS. The elongated hole-shaped recess 40 extends in the extending direction of the groove 11A. Further, both end portions 41, 42 in the longitudinal direction of the elongated hole-shaped recess 40 terminate in the groove wall surface 30. However, with respect to the elongated hole-shaped recess 40 formed at the corner of the first block 20, that is, at the end of the side wall surface 30, only one end terminates in the side wall surface 30 and the other end opens at the corner. ing. The plurality of long hole-shaped recesses 40 includes a long hole-shaped recess 40A that forms a row on the side close to the tread surface 10A in the side wall surface 30 and a long hole-shaped recess 40B that forms a row on the side close to the groove bottom 50. Are arranged in two rows. Therefore, as shown in FIG. 4, one elongated hole-shaped recess 40 </ b> A has an overlapping portion 60 with the other two elongated hole-shaped recesses 40 </ b> B at the position in the extending direction of the groove 11 </ b> A. All other slot-like recesses 40 have overlapping portions 60 as well.

  As described above, the characteristic configuration of the present invention is that the concave portion disposed on the side wall surface of the groove is formed into a long hole extending in the groove extending direction, and the end portion is terminated in the groove wall surface. That is, the plurality of long hole-shaped concave portions are arranged so as to overlap each other at the position in the groove extending direction. Since the concave portion 40 provided in the side wall surface 30 of the groove 11A extends in the extending direction of the groove 11A and the end portion ends in the side wall surface 30, it is assumed that even if a crack occurs in the concave portion 40. The cracks are difficult to propagate over a wide range of the side wall surface 30. Moreover, these were arrange | positioned so that the some elongate recessed part 40 might mutually overlap in the position of the extension direction of the groove | channel 11A. Thereby, at each position in the extending direction of the groove 11A, there is no position where the long hole-shaped concave portion 40 is not disposed when viewed from the tread surface 10A toward the groove bottom 50. The shear rigidity can be reduced uniformly, and as a result, the wear resistance of the first block 20 is improved. Therefore, according to the pneumatic tire 100 which is one embodiment of the present invention, it is possible to improve the wear life and the tire durability (crack resistance) in a well-balanced manner.

  Further, as a secondary effect, in the present invention, an increase in shear rigidity can be suppressed to a low level even if the tread rubber thickness is reduced.

  In recent years, high fuel efficiency performance is required for tires, and it is required to reduce rolling resistance that shows energy loss in tires. In order to reduce the rolling resistance, it is particularly effective to reduce the deformation energy loss accompanying the rolling load of the tire, and the most effective means is to make the tread rubber thin. Until now, thinning the tread rubber has reduced the tire groove depth and consequently shortened the wear life of the tire, so it has been difficult to achieve both a reduction in rolling resistance and an improvement in wear life. It was. However, according to the present invention, since the wear life of the tire can be effectively improved by providing the recess on the groove wall surface, even if the tread rubber is made thinner, the block shear is smaller than that of the tire without the recess on the groove wall surface. It is possible to keep the increase in rigidity low and keep the wear life long.

  Moreover, according to the study by the present inventor, in a tire having a thick tread rubber, the relationship between the groove depth and the wear life is almost proportional, whereas in a tire having a thin tread rubber, the wear life is remarkably reduced. Got. This is presumably because when the tread rubber is made thinner, the shear rigidity of the tread land portion is increased, and a greater shear force is generated even if the amount of deformation accompanying the load rolling of the tire is constant. For this reason, it is particularly effective in a tire having a thin tread rubber to provide a recess in the groove wall surface as in the present invention to keep the shear rigidity of the tread land portion low.

  Therefore, in the tire of the present invention including the tire 100, the rubber thickness of the tread portion can be 10 mm or less. As a result, it is possible to obtain a tire in which not only the wear life and tire durability but also rolling resistance is improved in a well-balanced manner.

  In the tire according to the present invention, the ratio R of the dimension occupied by the elongated hole-shaped recess to the shortest distance along the side wall surface from the tread surface to the groove bottom of the groove having the elongated hole-shaped recess is the groove extension of the groove It is preferably the same at a position of 60% or more of the directional distance, and more preferably the same at a position of 75% or more. As shown in FIG. 4, for the first circumferential groove 11 </ b> A of the tire 100, the shortest distance along the side wall surface 30 from the tread portion surface 10 </ b> A to the groove bottom 50 is “z”. The dimension occupied by the elongated hole-shaped recess is “2 × y” in the overlapping portion 60. Here, x represents the width in the longitudinal direction of the long hole-shaped recess 40, and y represents the width in the short direction of the long hole-shaped recess 40. With respect to the side wall surface 30, the elongated hole-like recesses 40 overlap at almost all positions in the extending direction of the groove 11 </ b> A. Therefore, the ratio R takes a constant value of 2 × y / z at this overlapping portion. Therefore, the shear rigidity can be lowered more uniformly within the range of the groove extending direction in which the elongated hole-shaped recess 40 is disposed, and the wear resistance in the first block is further improved. In the present specification, the “longitudinal direction” of the elongated hole-shaped concave portion means a direction connecting both end portions where the width of the concave portion is maximum, and the “short direction” means a direction perpendicular to the longitudinal direction. Shall mean.

  Here, “same” in the present invention does not mean that the values are mathematically strict and equal, but in view of the common general knowledge of pneumatic tires, a level that allows manufacturing errors. Of course, it is a thing. The same applies to various values such as the groove width and groove depth.

  The long hole-shaped recess 40 may be disposed in a depth range of 40% to 90% of the groove depth d (FIG. 3A) from the tread surface 10 </ b> A to the groove bottom 50 in the groove wall surface 30. preferable. If it is less than 40%, the elongated hole-shaped recess is too close to the tread surface 10A, and the elongated hole-shaped recess disappears due to wear at a relatively early stage, and the effect of the present invention to reduce the shear rigidity is lost. It is. On the other hand, if it exceeds 90%, the elongated hole-like concave portion is too close to the groove bottom 50, and the groove bottom tends to be subjected to shearing force, so that cracks are likely to occur.

  As shown in FIG. 3, at least a part of the elongated hole-shaped recess has a lower end 44 at the upper end of the treadware indicator 70 (usually 1.6 mm from the groove bottom). It is preferable to be in the same groove depth position as the position (1). Thereby, the effect of the present invention can be obtained until the end of use.

  The long hole-shaped recess 40 preferably has a longitudinal width x in the range of 2 to 10 mm and a short-side width y in the range of 0.5 to 2 mm. This is because if the longitudinal width x is less than 2 mm, the effects of the present invention may not be sufficiently obtained, and if it exceeds 10 mm, cracks may easily develop. In addition, when the width y in the short direction is less than 0.5 mm, the radius of curvature of the bottom of the recess is too small, so that cracks are likely to occur. When it exceeds 2 mm, it is difficult to provide an overlapping portion. This is because the effects of the present invention may not be sufficiently obtained.

  In the present embodiment, the elongated hole-shaped recesses 40A and 40B are provided so that the longitudinal direction thereof is parallel to the tread portion surface 10A at the same groove depth position in the groove wall surface 30, respectively. In this case, it is preferable that the distance w between the end portions of the adjacent elongated hole-shaped recesses 40 is in the range of 1 to 2 mm. If the distance is 1 mm or more, there is no concern that the distance between the end portions is too short and cracks are likely to propagate. This is because the effect of reducing the above can be more sufficiently secured.

  In the present embodiment, the slot-like recesses 45 and the slot-like recesses provided on the side wall surfaces of other grooves have the same arrangement relationship as the slot-like recesses 40. In the tire 100, the recesses in the side wall surfaces of the first circumferential groove 11A and the first width direction groove 14 that define and form the first block 20 have been described so far. A similar slot-like recess is formed.

  However, the present invention is not limited to this embodiment, and various modifications can be made within the scope of the gist of the present invention. For example, in the tire 100, the tread tread has a block pattern based on a rectangular block, but other block patterns may be used, or only a circumferential groove is provided and only a rib-shaped land portion is disposed as a tread land portion. A rib pattern may be used.

  Further, in the tire 100, the example in which the elongated hole-shaped concave portions are provided on the side wall surfaces of all the grooves has been described. However, in the present invention, the tread land portion is defined only for the tread land portion whose shear rigidity is desired to be lowered as necessary. A slot-like recess can be provided on the side wall surface of the groove. That is, a long hole-shaped recess may be provided on at least one side wall surface of at least some of the grooves so that the desired shear rigidity of the land portion of the tread can be reduced. For example, in a tire whose mounting direction is determined, it can be provided only on the side wall surface of the circumferential groove on the outer side in the tire mounting direction in order to counter lateral force.

  Moreover, the aspect of the long hole-shaped recessed part provided in the side wall surface of a groove | channel is not limited of this embodiment, A various change is possible, for example, the following embodiments are mentioned.

(Embodiment 2)
The elongated hole-shaped recess 80 of the present embodiment is a substantially elliptical recess whose end is rounded, and the longitudinal direction thereof is a predetermined angle with respect to the extending direction of the groove (that is, the direction parallel to the tread surface). It is inclined at. About the some long hole-shaped recessed part 80, the longitudinal direction both ends 82 and 83 are in the same groove depth position, respectively, and it adjoins mutually and is arrange | positioned adjacently. Therefore, each long hole-shaped recessed part 80 has the long hole-shaped recessed part and overlap part 81 of the both sides which adjoin in the position of a groove extension direction.

  In the present invention, since the long hole-shaped concave portion needs to extend in the groove extending direction, the longitudinal direction of the long hole-shaped concave portion is in a range of 45 ° to −45 ° with respect to the groove extending direction. It becomes the inside inclination angle. When a crack occurs in the recess, the crack is likely to proceed in the longitudinal direction of the recess. If the longitudinal direction of the elongated hole-shaped concave portion is inclined with respect to the groove extending direction, cracks are less likely to propagate in the groove wall surface, and as a result, the crack resistance performance is improved.

  The present embodiment is the same as the first embodiment except for the points described above.

(Embodiment 3)
The elongated hole-shaped recess 85 of this embodiment has a shape in which recesses extending by a predetermined distance in the groove extending direction at two groove depth positions are connected by a recess perpendicular to the groove extending direction. About the some long hole-shaped recessed part 85, the longitudinal direction both ends 87 and 88 are in the same groove depth position, respectively, and adjoin and mutually arrange | position. Therefore, each long hole-shaped recessed part 85 has the long hole-shaped recessed part and overlapping part 86 of the both sides which adjoin in the position of a groove extension direction.

  The present embodiment is the same as the first and second embodiments except for the points described above.

(Embodiment 4)
The elongated hole-shaped recess 90 of the present embodiment has a “round shape” shape with rounded corners. The plurality of elongated hole-like recesses 90 are arranged in the side wall surface at the same groove depth position on the side close to the tread part surface so that the corners face the tread part surface side, and at the groove bottom. A plurality of arrays are arranged at the same depth position on the near side so that the corners face the groove bottom side. These two rows of elongated hole-shaped recesses are arranged so that the ends of the elongated hole-shaped recesses in one row are positioned near the corners of the elongated hole-shaped recesses in the other row. For this reason, each long hole-shaped recessed part 90 has the long hole-shaped recessed part and overlapping part 91 of the both sides which adjoin the other row | line | column in the position of a groove extension direction.

  The present embodiment is the same as the first and second embodiments except for the points described above.

  Next, in order to further clarify the effects of the present invention, a comparative evaluation performed using pneumatic tires according to the following examples and comparative examples will be described.

(Example tire 1)
The tire described with reference to FIGS. The tire size was 195 / 65R15. Each configuration of the tread portion is as follows.
Groove depth of each circumferential groove and width direction groove: 7 mm
Groove width of each circumferential groove and width direction groove: 4 mm
Block width of each block: 25mm
Dimension of long hole-shaped recess: Longitudinal width x = 5 mm, Short width y = 0.7 mm
Minimum distance z = 7.02 mm along the side wall surface from the tread surface to the groove bottom
Therefore, the ratio R = 0.199.
Edge interval w = 1mm between adjacent slot-shaped recesses
Depth of slotted recess: 1mm
Groove depth position of the long hole-shaped concave portion: The long hole-shaped concave portions in the row on the groove bottom side are arranged so that the lower end is positioned at 1.4 mm from the groove bottom. In addition, when the name of the row on the tread surface side is a hole-shaped recess, the lower end is arranged at a position 2.8 mm from the groove bottom.
Rubber thickness of tread part: 8.8mm

(Comparative tire 1)
A tire similar to the example tire 1 was used as the comparative example tire 1 except that the long hole-shaped recess was not provided.

(Comparative tire 2)
Instead of providing a long hole-like recess as in the tire 1 of the embodiment, instead of a row of continuous recess lines at a position 1.4 mm from the groove bottom, that is, the end does not terminate in the side wall surface, A tire similar to Example Tire 1 was used as Comparative Example Tire 2 except that a long hole-like recess opened in the part was provided.

(Comparative tire 3)
Of the two rows of long hole-shaped recesses of Example Tire 1, the same tires as those of Example Tire 1 are compared except that the long hole-shaped recesses on the tread surface side are not provided and one row of long hole-shaped recesses is provided. Example tire 3 was designated. That is, the comparative example tire 3 does not have an overlapping portion of the elongated hole-shaped recess.

(Comparative tire 4)
Example tire 1 except that two circular recesses (diameter 0.7 mm) are provided in place of the slot-like recesses at the groove depth position where the two rows of slot-like recesses are provided in the example tire 1. A tire similar to the above was designated as Comparative Example Tire 4. The interval between adjacent circular recesses was set so that each recess had an overlapping portion of 0.2 mm at both ends.

<Wear life>
The tires of Example 1 and Comparative Examples 1 to 4 were mounted on a 6J × 15 rim, and the front wheels were filled with air pressure of 250 kPa and the rear wheels of 240 kPa. This tire was mounted on a vehicle (Toyota Prius), and under a load of two passengers, the tire ran on a circuit course including a highway, an urban area, and a mountain road for 10,000 km. After running, the amount of wear in the tread portion was measured, and the running distance during complete wear was calculated from the measured value. The calculated travel distance is shown in Table 1 as an index with Comparative Example 1 as 100. A larger index indicates a longer wear life.

<Tire durability (crack resistance)>
The tires of Example 1 and Comparative Examples 1 to 4 were mounted on a 6J × 15 rim and filled with an air pressure of 250 kPa. A maximum load according to the JATMA standard was applied, and the tire was run on an indoor drum tester while promoting the deterioration of rubber in an ozone atmosphere. After running for 120 hours, for one block in the center of the tread, the lengths of the cracks generated on the side walls of the four grooves surrounding the four sides are totaled, and the ratio of the reciprocal is set to an index with Comparative Example 1 as 100. Table 1 shows. The larger the index, the higher the tire durability.

  As is apparent from Table 1, in Example 1, compared with Comparative Examples 1 to 4, the wear life can be improved without deteriorating the tire durability, and the wear life and the tire durability are improved in a well-balanced manner. It is possible to make it.

  According to the pneumatic tire of the present invention, it is possible to improve the wear life and the tire durability in a well-balanced manner.

DESCRIPTION OF SYMBOLS 100 Pneumatic tire 10 Tread part 10A Tread part surface 11A, 11B 1st circumferential groove 12A, 12B 2nd circumferential groove 13A, 13B 3rd circumferential groove 14 1st width direction groove 15A, 15B 2nd width direction groove 16A , 16B Third width direction groove 20 First block (tread land portion)
21A, 21B 2nd block (land of tread)
22A, 22B 3rd block (tread land)
23A, 23B Rib-shaped land (tread land)
30, 32 Side wall surface 40, 45 Long hole-shaped concave portion 41, 42 Both longitudinal ends of the long hole-shaped concave portion 40A 44 Lower end of the long hole-shaped concave portion 40B 50 Groove bottom of groove 11 51 Groove bottom of groove 14 60 Overlapping portion 70 Tread Wear indicator 71 Upper end of tread wear indicator 80, 85, 90 Long hole-shaped concave portion 81, 86, 91 Overlapping portion 82, 83 Both longitudinal ends of long hole-shaped concave portion 87 87, 88 Both longitudinal ends of long hole-shaped concave portion 85 92,93 Both ends in the longitudinal direction of the elongated hole-shaped recess 90

Claims (3)

A pneumatic tire having a plurality of grooves in the tread section defining the land portion of the tread,
A plurality of elongated hole shapes extending in the groove extending direction of at least one of the plurality of grooves in the groove extending direction and having at least one end of the both ends in the longitudinal direction terminating in the side wall surface. Having a recess,
The pneumatic tire according to claim 1, wherein one of the elongated hole-like recesses has an overlapping portion overlapping with another of the elongated hole-like recesses at a position in the groove extending direction.   For the groove having the long hole-shaped concave portion, the ratio of the dimension occupied by the long hole-shaped concave portion to the shortest distance along the side wall surface from the surface of the tread portion to the groove bottom is 60% of the groove extending direction distance of the groove. The pneumatic tire according to claim 1, which is the same in the above positions. Has a treadwear indicator,
The pneumatic tire according to claim 1 or 2, wherein at least a part of the plurality of elongated hole-shaped recesses has a lower end at the same groove depth position as an upper end of the treadwear indicator.

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