JP2002240513A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of improving wetting performance and low noise property without sacrificing the other performance such as maneuvering stability. SOLUTION: Circumferential main grooves 14 and 16 and lateral grooves 20 and 24 are formed in a tread 12. Circumferentially continuing rib 18 is disposed on the tire equatorial plane CL to provide high maneuvering stability. Both ends of the rib 18 are provided with recessed parts 28 for drainage in a circumferentially long triangular shape separated from each other circumferentially. Water interposed between the rib 18 and the road surface is drained to the circumferential main groove 14 with these recessed parts 28 for drainage, thereby improving the wetting performance. The recessed parts 28 has a circumferentially long triangular shape, so that circumferential rigidity of the rib 18 is not reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to one or more circumferential land portions continuous in the circumferential direction defined by circumferential grooves in a central region of a tread portion, and extends from the center side of the tread portion to the tread end side, and The present invention relates to a pneumatic tire provided with a plurality of lateral grooves inclined in one direction with respect to a circumferential direction, and more particularly to a pneumatic tire having improved wet performance and low noise without sacrificing other performances.

[0002]

2. Description of the Related Art Conventionally, as a method of improving steering stability on dry road surfaces, particularly, handle response at a small steering angle,
It has been considered that at least one circumferential rib extending in the circumferential direction is provided substantially at the center of the tread contact surface portion, and the rigidity of the rib is increased by increasing the width of the circumferential rib.

However, when the width of the circumferential rib is increased, the negative ratio in the central region of the tread contact portion decreases, and there is a problem that the drainage property is reduced and the wet performance is deteriorated.

[0004] As a method for achieving both steering stability and wet performance as described above, at present, the width of the circumferential rib is increased, and a notch-like lateral groove which is similarly opened only on both sides of the circumferential rib is provided. Is considered.

[0005]

However, if a notched lateral groove is formed in the circumferential rib, the rigidity of the land in the rotational direction of the circumferential rib is reduced, and the steering stability on a dry road surface, particularly when the steering angle is small, is reduced. There is a concern that steering wheel responsiveness and pattern noise may deteriorate.

[0006] In consideration of the above fact, the present invention relates to a circumferentially continuous groove defined by a circumferential groove in the central region of the tread portion.
In pneumatic tires with more than one circumferential land,
It is an object of the present invention to provide a pneumatic tire capable of improving wet performance and low noise without sacrificing other performances such as steering stability.

[0007]

According to a first aspect of the present invention, there is provided a pneumatic pneumatic tire having at least one circumferential land portion continuous in a circumferential direction defined by at least a circumferential groove in a central region of a tread portion. In the tire, the circumferential land portion is provided, at least at one end in the tire axial direction, with substantially triangular concave portions that are long in the circumferential direction as viewed from the tread surface side and are provided at intervals in the circumferential direction. It is characterized by:

Next, the operation of the pneumatic tire according to the first aspect will be described.

In the pneumatic tire according to the first aspect, since one or more circumferential land portions continuous in the circumferential direction are provided in the central region of the tread portion, the blocks divided in the circumferential direction in the central region of the tread portion. The rigidity of the tread portion central region is higher than that of the pattern provided with, and the steering stability on a dry road surface, particularly, the handle response at a small steering angle can be improved.

The pneumatic tire is mounted in a specified direction such that the wide side of the recess in the tire axial direction is the stepping side (the side that first comes into contact with the road surface) when the vehicle advances.

[0011] With this mounting, when traveling on a wet road surface, the tire is long in the circumferential direction provided at the end of the circumferential land portion, and has a width in the tire axial direction from one side in the circumferential direction to the other side. The water intervening between the circumferential land portion and the road surface can be discharged to the circumferential groove by the concave portion having gradually decreasing, and the wet performance can be improved.

That is, the water interposed between the widthwise central portion of the circumferential land portion and the road surface is taken into the concave portion at the axially long portion of the concave portion, and the water taken in with respect to the circumferential direction of the concave portion. (The side surface is inclined in the circumferential direction because the width of the concave portion in the tire axial direction is gradually reduced from one side to the other side in the circumferential direction, so that the concave portion smoothly flows along the circumferential groove.) Can be discharged to

Here, when compared at the same negative ratio, a concave portion which is long in the circumferential direction when viewed from the tread surface and whose width in the tire axial direction gradually decreases from one side to the other side in the circumferential direction is provided. The circumferential land portion can secure the land rigidity in the circumferential direction more than the circumferential land portion provided with a long lateral groove extending in the width direction and crossing (or substantially traversing) the land portion in the tire axial direction. , High steering stability can be obtained.

Further, in a conventional tire having a circumferential land portion provided with a lateral groove, the edge component on the stepping side extending in the tire axial direction is long, and when the lateral groove comes into contact with the road surface, the lateral groove per unit time with respect to the road surface is reduced. Although the contact area of the tire increases sharply, noise is likely to occur, but the substantially triangular concave part that is long in the circumferential direction has a short edge component on the stepping side extending in the tire axis direction, and the contact area with the road surface per unit time increases. It is difficult to generate noise because it is small.

The tread central region is a central region when the tread is divided into three equal parts in the tire axial direction.

According to a second aspect of the present invention, there is provided one or more circumferentially continuous land portions provided in a central region of the tread portion and defined by a circumferential groove, and from a center side of the tread portion to an end side of the tread portion. In the pneumatic tire provided with a plurality of extending lateral grooves in the tread, the circumferential land portion is provided with a recess at a circumferential direction at least at one end in the tire axial direction, and the tread surface side The shape of the concave portion as viewed from above is characterized in that it is long in the circumferential direction and the width in the tire axial direction is gradually reduced from one side in the circumferential direction to the other side.

Next, the operation of the pneumatic tire according to claim 2 will be described.

In the pneumatic tire according to the second aspect, since at least one circumferential land portion continuous in the circumferential direction is provided in the central region of the tread portion, the block divided in the circumferential direction in the central region of the tread portion. The rigidity of the tread portion central region is higher than that of the pattern provided with, and the steering stability on a dry road surface, particularly, the handle response at a small steering angle can be improved.

When the vehicle is traveling on a wet road surface, the water present between the circumferential land portion and the road surface is discharged into the circumferential groove by a circumferentially long substantially tapered recess provided at the end of the circumferential land portion. And wet performance can be improved.

Here, when compared at the same negative ratio, the circumferential land portion provided with a substantially tapered concave portion which is long in the circumferential direction when viewed from the tread surface extends in the width direction and crosses (or substantially crosses) the land portion. The rigidity of the land portion in the circumferential direction can be secured more than that of the circumferential land portion provided with a transverse groove that crosses the horizontal direction, and high steering stability can be obtained.

In a conventional tire having a circumferential land portion provided with a lateral groove, when the lateral groove comes into contact with a road surface, the contact area of the lateral groove with the road surface sharply increases, so that noise is easily generated. The concave portion that is long in the direction has a short edge component on the stepping side extending in the tire axial direction, and the contact area on the road surface per unit time is little increased, so that noise is hardly generated.

According to a third aspect of the present invention, in the pneumatic tire according to the second aspect, the substantially triangular concave portion has one side formed by a groove wall of the circumferential groove and a tire equatorial plane extending from the groove wall. It is characterized by comprising two sides extending to the side and inclined with respect to the circumferential direction, wherein the angle between the groove wall and the side on the kick-out side is an acute angle.

Next, the operation of the pneumatic tire according to claim 3 will be described.

First, a triangular shape of a concave portion that is long in the circumferential direction is constituted by one side formed by a groove wall of a circumferential groove and two sides extending from the groove wall toward the tire equatorial plane and inclined with respect to the circumferential direction. Assuming that the angle between the groove wall and the side on the kick-out side is an acute angle, water trapped in the concave portion when traveling on a wet road surface is
It flows along the side on the stepping-in side where the angle with respect to the circumferential groove is set relatively small, and can be smoothly discharged to the circumferential groove.

According to a fourth aspect of the present invention, in the pneumatic tire according to the third aspect, the substantially triangular concave portion has one side formed by the groove wall of the circumferential groove and the side on the kick-out side. It is characterized by being isosceles triangles of the same length.

Assuming that the shape of the concave portion is such an isosceles triangle, for example, the concave portion 100 as shown in FIG.
Compared to a triangle having an extremely short length 0B and a long triangle 100C on the stepping side as shown in FIG. 10, water can be efficiently taken into the concave portion, which is preferable.

According to a fifth aspect of the present invention, in the pneumatic tire according to any one of the first to fourth aspects,
The bottom surface of the concave portion is an inclined surface whose depth gradually increases toward the corner on the kicking side from the side on the stepping side.

Next, the operation of the pneumatic tire according to claim 5 will be described.

If there is a concave portion in the land portion, there is a problem that noise is generated at the time of contact with the ground, and the noise tends to increase when the depth changes abruptly or when the step amount of the concave portion is large.

[0030] In the pneumatic tire according to the fifth aspect, the bottom surface of the concave portion is an inclined surface whose depth gradually increases toward the corner on the kick-out side from the side on the stepping side, so that the concave portion contacts the road surface. Since the depth gradually changes, the generation of noise can be suppressed.

According to a sixth aspect of the present invention, in the pneumatic tire according to the fifth aspect, the inclined surface is a smooth curved surface protruding outward in the tire radial direction.

Next, the operation of the pneumatic tire according to claim 6 will be described.

By forming the inclined surface with a smooth curved surface that protrudes outward in the tire radial direction, generation of noise can be further suppressed.

According to a seventh aspect of the present invention, there is provided the pneumatic tire according to any one of the first to sixth aspects, wherein:
The stepped side end of the concave portion is the same height as the tread surface of the circumferential land portion.

Next, the operation of the pneumatic tire according to claim 7 will be described.

Since the stepped end of the concave portion that comes into contact with the road surface first is set at the same height as the tread surface of the circumferential land portion,
Noise generation at the start of contact can be suppressed. In particular,
The combination with claim 6 is preferred.

[0037] The invention according to claim 8 provides the pneumatic tire according to any one of claims 1 to 7,
The circumferential length of the concave portion is set within a range of 10 to 50% of the ground contact length.

Next, the operation of the pneumatic tire according to claim 8 will be described.

If the circumferential length of the recess is less than 10% of the ground contact length, the effect of improving the wet performance may be insufficient.

When the circumferential length of the concave portion exceeds 50% of the ground contact length, the wet performance is improved, but the rigidity of the circumferential land portion is reduced, and the steering stability may be reduced.

Therefore, it is preferable to set the circumferential length of the concave portion within a range of 10 to 50% of the ground contact length.

According to a ninth aspect of the present invention, in the pneumatic tire according to any one of the first to eighth aspects,
The maximum depth of the recess is 5 times the groove depth of the adjacent circumferential groove.
It is characterized in that it is set within the range of 0 to 100%.

Next, the operation of the pneumatic tire according to the ninth aspect will be described.

If the maximum depth of the recess is less than 50% of the groove depth of the adjacent circumferential groove, the effect of improving the wet performance may be insufficient.

According to a tenth aspect of the present invention, in the pneumatic tire according to any one of the first to ninth aspects, the width of the recess in the tire axial direction is 5 times the width of the circumferential land portion. It is characterized in that it is set within the range of ６０60%.

Next, the operation of the pneumatic tire according to the tenth aspect will be described.

If the width of the concave portion in the tire axial direction is less than 5% of the width of the circumferential land portion, the effect of improving the wet performance may be insufficient.

If the width of the concave portion in the tire axial direction exceeds 60% of the width of the circumferential land portion, the rigidity of the circumferential land portion is reduced, and there is a possibility that steering stability may be reduced.

Therefore, the width of the concave portion in the tire axial direction is preferably set within the range of 5 to 60% of the width of the circumferential land portion, and more preferably within the range of 5 to 30%.

According to an eleventh aspect of the present invention, in the pneumatic tire according to any one of the first to tenth aspects, the pitch in the tire circumferential direction of the concave portion is 20 to less than the ground contact length.
It is characterized in that it is set within the range of 75%.

Next, the operation of the pneumatic tire according to the eleventh aspect will be described.

The pitch in the tire circumferential direction of the concave portion is 2
If it is less than 0%, the rigidity of the land portion in the circumferential direction is reduced, and there is a possibility that steering stability is reduced.

The pitch in the tire circumferential direction of the concave portion is 7 times the contact length.
If it exceeds 5%, the effect of improving the wet performance may be insufficient.

Therefore, it is preferable to set the pitch of the concave portion in the tire circumferential direction within the range of 20 to 75% of the ground contact length.

Here, in Japan, the pneumatic tire is mounted on a standard rim specified in JATMA YEAR BOOK (2001, Japan Automobile Tire Association Standard), and the applicable size and ply in JATMA YEAR BOOK is used. Maximum load capacity in rating (internal pressure-
Fill the tire with 100% internal pressure of the air pressure (maximum air pressure) corresponding to the bold load in the load capacity correspondence table, and apply the maximum load capacity of a single wheel in the applicable size described in the standard to the tire circumference of the contact surface. The maximum dimension in the direction.

In other regions, rims, internal pressures, loads, etc., are industrial standards valid in the region where the tire is manufactured or used. For example, in the United States, "The Tire and Rim
Association Inc. Year Book "In Europe, The Eu
ropean Tire and Rim Technical Organization Stand
ards Manual ”.

[0057]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the pneumatic tire of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the tread 12 of the pneumatic tire 10 of the present embodiment has a circumferential main groove extending along the tire circumferential direction (the direction of arrow A and the direction of arrow B) on both sides of the tire equatorial plane CL. The circumferential main groove 16 is formed on both sides of the circumferential main groove 14 in the tire axial direction (the direction of arrow C).

On the tire equatorial plane CL, there are provided circumferentially continuous ribs 18.

Between the circumferential main groove 14 and the circumferential main groove 16, there are a circumferential main groove 14, a circumferential main groove 16, and a lateral groove 20 inclined in the arrow B direction with respect to the tire axial direction. A substantially diamond-shaped block 22 to be partitioned is provided.

Further, on the outer side of the circumferential main groove 16 in the tire axial direction, the transverse main groove 16 and the lateral groove 2 inclined in the direction of arrow B are provided.
A substantially diamond-shaped block 26 is provided, which is defined by the blocks 4 and 4.

The pneumatic tire 10 has a specified rotation direction, and is mounted on a vehicle so as to rotate in the direction of arrow A when moving forward.

Drain recesses 28 are formed at both ends of the rib 18 in the tire axial direction.

As shown in FIG. 2, the drain recess 28 of the present embodiment has a shape, as viewed from the tread surface side, of one side 30 A formed by the groove wall of the circumferential main groove 14, and an angle with respect to the circumferential main groove 14. Is set at an acute angle, one side 30B on the kick-out side (side wall of the recess 28 for drainage), and one side 3 on the stepping side with a short length.
0C, one side 3 which is formed by the groove wall of the circumferential groove
0A and the side 30B on the kick-out side are isosceles triangles having the same length.

As shown in FIG. 3, the bottom surface 32 of the drainage concave portion 28 extends from the side 30C on the stepping side to the corner on the kicking side, and has a curved surface (a convex portion) which gradually increases in depth in the tire radial direction. In the embodiment, the radius is a radius of curvature R), and the side 30C on the stepping side is the same height as the tread surface 18A of the rib 18.

As shown in FIG. 2, the circumferential length L ₁ of the drain recess 28 is 10 to 50 times the ground length L ₀ (see FIG. 1).
% Is preferably set. In this embodiment, the circumferential length L ₁ of the drain recess 28 is equal to the ground length L _0.
Is set to 18%.

As shown in FIG. 1, the width W ₁ of the recess 28 for drainage in the tire axial direction is preferably set within a range of 5 to 60% of the width W ₀ of the rib 18. In the present embodiment,
The width W ₁ of the drain recess 28 in the tire axial direction is set to 33% of the width W ₀ of the rib 18.

Tire circumferential pitch P of drainage recess 28
Is the ground contact length L ₀ (the ground contact shape is shown by a two-dot chain line in the figure)
Is preferably set within the range of 20 to 75% of the above. In the present embodiment, the tire circumferential pitch P of the drainage recess 28 is set to 38% of the contact length L _0.

The drainage recess 28 formed on one side of the tire equatorial plane CL and the drainage recess 28 formed on the other side are shifted by half a pitch in the tire circumferential direction. .

Further, as shown in FIG.
Is 96% of the groove depth H of the circumferential main groove 14.

Next, the operation of the pneumatic tire 10 of the present embodiment will be described.

In the pneumatic tire 10, the tread 1
2, a circumferentially extending rib 18 on the tire equatorial plane CL
Is provided, it is possible to improve the steering stability on a dry road surface, particularly the steering wheel responsiveness at a small steering angle.

The pneumatic tire 10 is mounted on the vehicle with the direction specified so that the short side 30C of the drainage concave portion 28 is on the stepping side when the vehicle advances.

When the vehicle is running on a wet road surface, the water in the ground contact surface is drained by the circumferential main grooves 14 and 16 and the lateral grooves 20 and 24.

Further, since the drainage recesses 28 provided at both ends of the rib 18 smoothly and quickly discharge water interposed between the rib 18 and the road surface into the circumferential main groove 14 on the side of the rib.
Wet performance is improved.

The drain recess 28 has a short edge component on the stepping side extending in the tire axial direction, has a small increase in the contact area with the road surface per unit time, and has a gradually changing depth when coming into contact with the road surface. Generation of noise can be suppressed. Second Embodiment A pneumatic tire according to a second embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 4, the tread 42 of the pneumatic tire 40 of the present embodiment has a circumferential main groove 44 extending along the tire circumferential direction on the tire equatorial plane CL. A circumferential main groove 46 extending in the tire circumferential direction is formed on both sides of the tire 44, and a circumferential main groove 48 is formed outside the circumferential main groove 46 in the tire axial direction.

A circumferentially continuous rib 50 is provided between the circumferential main groove 44 and the circumferential main groove 46.

Between the circumferential main groove 46 and the circumferential main groove 48, there are a circumferential main groove 46, a circumferential main groove 48, and a lateral groove 52 inclined in the direction of arrow B with respect to the tire axial direction. A substantially diamond-shaped block 54 to be partitioned is provided.

On the outside of the circumferential main groove 48 in the tire axial direction, a substantially rhombus-shaped block 58 defined by the circumferential main groove 48 and a lateral groove 56 inclined in the direction of arrow B with respect to the tire axial direction. Is provided.

A drain recess 28 similar to that of the first embodiment is formed at the end of the rib 50 on the outer side in the tire axial direction.

The drain recess 28 formed on one rib 50 and the drain recess 28 formed on the other rib 50 are shifted from each other by a half pitch in the tire circumferential direction.

In the pneumatic tire 40 of this embodiment, the steering stability on a dry road surface is improved by two circumferentially continuous ribs 50 provided on both sides of the tire equatorial plane CL.

The drain recess 2 during wet running
The operation and effect of 8 are the same as those of the first embodiment.

In the present embodiment, the drainage recess 28 is provided only on one side of the rib 50, but the drainage recess 28 may be provided on both sides of the rib 50. [Other Embodiments] In the above embodiment, the shape of the drainage concave portion 28 as viewed from the tread surface side is an isosceles triangle. However, the present invention is not limited to this.
Shapes other than triangles as shown in (A) to (H) may be used. However, in any case, there is a portion which is long in the circumferential direction and whose width in the tire axial direction gradually decreases toward one side in the circumferential direction.

In the above embodiment, the drainage recess 28 is used.
The shape of the bottom surface 32 is an arc shape that protrudes outward from the tire when viewed from the side, but the present invention is not limited to this.
May be, for example, shapes as shown in FIGS. 6 (A) to 6 (C). (Test Example 1) Comparative Example 1 to confirm the effect of the present invention
Was prepared and the pneumatic tire of Example 1 to which the present invention was applied was subjected to a wet hydroplaning (linear and cornering) test, a dry steering stability test, and a pattern noise measurement. .

The pattern of the pneumatic tire used in the test is the pattern of the first embodiment shown in FIG.

In the pneumatic tire of Example 1, a drain recess is provided in the center rib. The dimensions of each part of the drain recess are as described in Table 1 below.

Comparative Example 1 is a pneumatic tire having the pattern shown in FIG. 7 in which the drainage recess is removed from the pneumatic tire of Example 1.

Wet hydroplaning (straight line) test: Feeling evaluation of the limit speed of hydroplaning occurrence when passing through a wet road surface at a water depth of 10 mm.

Wet hydroplaning (cornering) test: A critical lateral G immediately before hydroplaning occurs when passing on a wet road surface having a water depth of 10 mm and a radius of 80 m is measured.

[0092] Dry steering stability: Evaluation of the feeling of a test driver when sports were run on a circuit course in a dry state in various running modes.

Pattern noise: Feeling evaluation of in-vehicle sound by a test driver when coasting on a straight road in a dry state from 100 km / h.

The size of the tire used in the test was P
SR205 / 55R16, and the internal pressure was 2
At 20 kpa, the load is equivalent to two front passengers. The tire used in the test had a tread width of 140 mm and a ground contact length of 160 mm.

All the evaluations of the tests are indicated by an index with Comparative Example 1 being 100. The larger the numerical value, the better the performance.

[0096]

[Table 1]

Test Example 2 In order to confirm the effects of the present invention, a pneumatic tire of Comparative Example 2 and a pneumatic tire of Example 2 to which the present invention was applied were prepared. A wet hydroplaning (linear and cornering) test, a dry steering stability test, and a pattern noise measurement were performed.

The pattern of the pneumatic tire used in the test is the pattern shown in FIG. 4 of the second embodiment.

The pneumatic tire of Example 2 has the center 2
Each of the ribs is provided with a drainage recess. The dimensions of each part of the drainage recess are as shown in Table 2 below.

Comparative Example 2 is a pneumatic tire having the pattern shown in FIG. 8 except that the drainage recess is removed from the pneumatic tire of Example 2.

In each of the evaluations of the tests, the index is indicated by setting Comparative Example 2 to 100, and the larger the numerical value, the better the performance.

The evaluation of the test is as described in Table 2 below.

[0103]

[Table 2]

[0104]

As described above, the pneumatic tire of the present invention has an excellent effect that wet performance and low noise can be enhanced without sacrificing other performances.

[Brief description of the drawings]

FIG. 1 is a plan view of a tread of a pneumatic tire according to a first embodiment of the present invention.

FIG. 2 is an enlarged plan view of a rib.

FIG. 3 is a side view of a rib.

FIG. 4 is a plan view of a tread of a pneumatic tire according to a second embodiment of the present invention.

5 (A) to 5 (H) are plan views of ribs showing another embodiment of the drainage concave portion.

FIGS. 6A to 6C are side views of ribs showing another embodiment of the drainage recess.

FIG. 7 is a plan view of a tread of the pneumatic tire of Comparative Example 1.

FIG. 8 is a plan view of a tread of the pneumatic tire of Comparative Example 2.

FIG. 9 is a plan view of a concave portion.

FIG. 10 is a plan view of a concave portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pneumatic tire 12 Tread 14 Circumferential main groove (circumferential groove) 16 Circumferential main groove (circumferential groove) 18 Rib (circumferential land portion) 28 Drainage recess (recess) 32 Bottom surface 40 Pneumatic tire 42 tread 44 Circumferential main groove (circumferential groove) 46 Circumferential main groove (circumferential groove) 48 Circumferential main groove (circumferential groove) 50 Rib (circumferential land portion)

Claims (11)

[Claims] 1. A pneumatic tire provided with at least one circumferential land portion continuous in a circumferential direction defined by at least a circumferential groove in a tread portion central region, wherein the circumferential land portion includes: A pneumatic tire characterized in that at least one end in the tire axial direction is provided with substantially triangular recesses which are long in the circumferential direction as viewed from the tread surface side and are spaced apart in the circumferential direction. 2. A tread having one or more circumferential land portions provided in a central region of the tread portion and continuous in a circumferential direction and defined by a circumferential groove, and a plurality of lateral grooves extending from the tread portion center side to the tread end side. In the pneumatic tire provided, in the circumferential land portion, at least at one end in the tire axial direction, a recess is provided at intervals in the circumferential direction, the shape of the recess as viewed from the tread surface side Is a pneumatic tire that is long in the circumferential direction and has a width in the tire axial direction gradually reduced from one side to the other side in the circumferential direction. 3. The substantially triangular concave portion includes one side formed by a groove wall of the circumferential groove, and two sides extending from the groove wall toward the tire equatorial plane and inclined with respect to the circumferential direction. The pneumatic tire according to claim 2, wherein the angle between the groove wall and the side on the kick-out side is an acute angle. 4. The substantially triangular concave portion is an isosceles triangle having the same length as one side formed by the groove wall of the circumferential groove and the side on the kick-out side. The pneumatic tire as described. 5. The bottom surface of the concave portion is an inclined surface whose depth gradually increases from a side on a stepping side toward a corner on a kicking-out side.
The pneumatic tire according to the paragraph. 6. The pneumatic tire according to claim 5, wherein the inclined surface is a smooth curved surface protruding outward in the tire radial direction. 7. The pneumatic pneumatic pump according to claim 1, wherein the stepped end of the recess is flush with the tread surface of the circumferential land portion. tire. 8. The circumferential length of the concave portion is 10 times the ground length.
The pneumatic tire according to any one of claims 1 to 7, wherein the pneumatic tire is set within a range of 50% to 50%. 9. The method according to claim 1, wherein a maximum depth of the concave portion is set within a range of 50 to 100% of a groove depth of an adjacent circumferential groove. 2. The pneumatic tire according to item 1. 10. The tire according to claim 1, wherein the width of the recess in the tire axial direction is set within a range of 5 to 60% of the width of the circumferential land portion. The pneumatic tire according to the paragraph. 11. The air according to claim 1, wherein a pitch in the tire circumferential direction of the concave portion is set in a range of 20% to 75% of a ground contact length. Containing tires.