JP2001146104A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve running performance on an ice and snow road. SOLUTION: A plurality of block rows are formed by providing vertical grooves 3 extended in a peripheral direction and a plurality of cross grooves 4 extended to be crossed with these vertical grooves 3 in a tread surface 2. The block row includes a first block row formed by a block with protruded part provided with a protruded part protruding in a vertical groove side and a second block row formed by a block with recessed part provided with a recessed part and to be arranged in a position mutually opposing the recessed part through the vertical groove to the protruded part. Ratio (WP/WB1) of maximum width WB1 of the block with protruded part to a protruding amount WP of the protruded part and ratio (WH/WB2) of maximum width WB2 of the block with recessed part to a recessed amount WH of the recessed part are set to 0.04 to 0.15. Ratio (LP/LB1) of maximum length LB1 of the block with protruded part to a maximum length LP of the protruded part and ratio (LH/LB2) of maximum length LH of the block with recessed part to a length LB2 of the recessed part are set to 0.3 to 0.4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire suitable for use as, for example, a heavy-duty radial tire capable of improving abrasion resistance while improving running performance on icy and snowy roads.

[0002]

2. Description of the Related Art In recent years,
When traveling on icy and snowy roads, studless tires are increasingly used. Such studless tires generally use a relatively soft rubber material for the tread rubber, or adopt a block pattern with a high snow-biting property on the tread surface to improve running performance on icy and snowy roads, and use vertical grooves. For example, the width of the lateral groove is increased, and the land ratio (the ratio of the contact area) is significantly reduced. That is, a large driving force and a large braking force are obtained by a snow column shearing force when cutting and cutting a large amount of snow in the groove. Further, by providing a large number of sipes or the like in each block, an edge component that scratches a road surface is increased, and running performance on icy roads is improved.

[0003] In recent years, studless tires have been used and crushed not only in winter but also in summer as they are, so that it is necessary to improve wear resistance in consideration of running in other than winter. . However,
Studless tires have low block stiffness due to the soft tread rubber, reduction of the land ratio of the tread surface, and the engraving of many sipes. is there. In particular, when the above-mentioned technology is applied to the tread pattern of a heavy load radial tire having a high contact pressure, uneven wear and further reduction of the tire life are caused, and when the land ratio is further reduced, a mirror surface called a mirror burn is obtained. There is a problem that the grip performance on the transformed ice surface is reduced.

[0004] The present invention has been devised in view of the above problems, and an object of the present invention is to provide a pneumatic tire capable of improving abrasion resistance while improving grip performance on snowy and icy roads. And

[0005]

The invention according to claim 1 of the present invention is characterized in that a tread surface is provided with a vertical groove extending in the tire circumferential direction and a plurality of horizontal grooves intersecting with the vertical groove. A pneumatic tire in which a plurality of block rows in which blocks are arranged in a tire circumferential direction are formed in a plurality of rows, wherein the block rows are provided at substantially middle positions in a circumferential direction of a block vertical wall surface facing the vertical grooves. A first block row composed of a block with a convex portion provided with a convex portion protruding to the side, and a block with a concave portion provided with a concave portion recessed toward the inside of the block at a substantially intermediate position in the circumferential direction of the vertical wall surface of the block; A second block row in which the concave portion is arranged at a position facing the convex portion of the block with the convex portion via a vertical groove, and a maximum width of the convex portion block in the tire axial direction on a tread surface. The ratio of the amount of projection WP of B1 and the convex portion (W
P / WB1), and the ratio (WH / W) between the maximum width WB2 of the block with the concave portion in the tire axial direction and the concave amount WH of the concave portion.
B2) is set to 0.04 to 0.15, and a ratio (LP / LB1) between the maximum circumferential length LB1 of the block with the convex portion and the maximum length LP of the convex portion in the tire circumferential direction, And the maximum length LH of the block with the concave portion in the tire circumferential direction.
(LH / LB)
Characteristically, 2) is set to 0.3 to 0.4.

As described above, by providing the convex and concave portions having a certain size in the blocks facing each other with the vertical groove interposed therebetween, the edge component of the vertical groove can be increased and the running performance on an icy road can be improved. sell. In addition, by disposing the convex and concave portions of each block at positions facing each other, even if the vertical grooves are linear, it is possible to secure the snow column shearing force in the vertical grooves, and without changing the land ratio. In addition to improving the grip performance on the road, wet grip performance can be secured without obstructing the flow of drainage. In addition, by arranging the convex portion and the concave portion at positions facing each other and limiting the size of the block relative to the block, deterioration of wear resistance can be suppressed.

In the invention according to a second aspect of the present invention, in the block with convex portions, both ends in the circumferential direction of the vertical wall surface of the block are inclined from the groove bottom side of the vertical groove toward the tread surface side into the block. The notch is formed by the slope, so that the protrusion is formed between the slopes, and the block with the recess faces the intermediate portion of the block vertical wall surface in the circumferential direction from the groove bottom side of the vertical groove toward the tread surface side. The pneumatic tire according to claim 1, wherein the concave portion is formed by being cut out by a slope inclined toward the inside of the block.

According to a third aspect of the present invention, the vertical groove is
3. The pneumatic tire according to claim 1, wherein a groove width in the tread surface is substantially constant.

According to a fourth aspect of the present invention, the block with the convex portion extends from both edges in the circumferential direction of the convex portion and crosses the inside of the block to form the block with the convex portion substantially three times.
In addition to the first siping for equally dividing, the block with the concave portion extends from both circumferential edges of the concave portion and traverses the inside of the block to form the second siping for substantially equally dividing the block with the concave portion into three. The pneumatic tire according to any one of claims 1 to 3, wherein the pneumatic tire is provided.

According to a fifth aspect of the present invention, the convex portion and the concave portion have a length in a tire radial direction of 40 to 50% of a depth of the vertical groove. 5. The pneumatic tire according to any one of items 1 to 4.

According to a sixth aspect of the present invention, in the first siping and the second siping, a depth of the first siping and the second siping is greater than a length of the convex portion and the concave portion in a tire radial direction, and a depth of the vertical groove. 5. The method according to claim 4, wherein the ratio is 60% or less.
It is a pneumatic tire of the statement.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a development view of a tread surface 2 of the pneumatic tire of the present embodiment. The pneumatic tire of this example is a heavy-duty radial tire used for, for example, trucks and buses, and has a longitudinal groove 3 extending in the tire circumferential direction on a tread surface 2 and a plurality of longitudinal grooves 3 intersecting with the longitudinal groove 3. A lateral groove 4 is provided.

The vertical groove 3 of the present embodiment includes a single vertical groove 3a extending linearly in the tire circumferential direction on the tire equator C and outer vertical grooves 3b arranged on both outer sides thereof. Three are illustrated. The horizontal groove 4 has the inner vertical groove 3a and the outer vertical groove 3b.
And a lateral groove 4b extending between the outer vertical groove 3b and the tread end E. Thus, on the tread surface 2, a plurality of blocks, in this example, four rows, in which substantially rectangular blocks are arranged in the tire circumferential direction, are formed. The vertical groove 3 has a groove width measured on the tread surface 2 of, for example, 2.5 to 7.0 of the tread contact width TW.
It is preferably about 0%, more preferably about 3.5 to 6%, and still more preferably about 4.5 to 6.0%.

As shown in FIGS. 1 and 2, the block row is located at a substantially middle position in the tire circumferential direction of the block vertical wall surface 5 facing the vertical groove 3 (in this example, the outer vertical groove 3b side). A first block row R1, R1 composed of a block B1 having a convex portion provided with a convex portion 6 protruding toward the vertical groove 3, and a concave portion inward of the block at a substantially intermediate position of the block vertical wall surface 5 in the tire circumferential direction. It is composed of a block B2 having a concave portion provided with a concave portion 7, and the concave portion 7 is provided on the convex portion 6 of the block B1 having a convex portion.
And a second block row R2 arranged at positions facing each other via the outer vertical groove 3b.

The first block row R1, R1 of this embodiment is formed between the inner vertical groove 3a and the outer vertical groove 3b, and the second block row R2 is formed by the outer vertical groove 3b. Groove 3b
And the tread edge E. Therefore, the first block row R1 and the second block row R2 are adjacent on each side of the tire equator C with the outer vertical groove 3b interposed therebetween.

FIG. 2 (A) shows the block B1 with a convex portion.
As schematically shown in the figure, a slope SP, which inclines both ends in the circumferential direction of the block vertical wall surface 5 from the groove bottom side of the outer vertical groove 3b toward the tread surface 2 and into the inside of the block, is a part in this example. An example is shown in which the projections 6 are formed between the slopes SP, SP by notching. Thereby, step surfaces X1, X1 each having a substantially triangular shape and continuing to the inclined surface SP are formed on both sides of the convex portion 6. As shown schematically in FIG. 2B, the block B2 with concave portions is formed by blocking the intermediate portion of the block vertical wall surface 5 in the tire circumferential direction from the groove bottom side of the outer vertical groove 3b toward the tread surface 2 side. The recess 7 is formed by being cut out by a slope SH inclined inward. On both sides of the slope SH, step surfaces X2, X2 each having a substantially triangular shape and continuing to the block vertical side surface 5 are formed.

As described above, by providing the protrusions 6 and the recesses 7 in the blocks B1 and B2 adjacent to each other with the outer vertical groove 3b interposed therebetween, the edge component on the tread surface 2 increases, and the running performance on an icy road is improved. And the step surface X of the projection 6
1. The stepped surface X2 of the recess 7 causes a shearing force to cut the snow column compacted in the outer vertical groove 3b in the traveling direction, and the snow column combined with the snow column shearing force by the lateral groove 4 generates snow. Grip power during road driving can be greatly increased. In addition, as a result of the protrusions 6 and the recesses 7 being disposed at positions facing each other via the outer vertical groove 3b, for example, it is possible to ensure a substantially constant groove width of the outer vertical groove 3b. Wet grip performance can be ensured without impairing drainage inside. The arrangement of the convex portion 6 and the concave portion 7 at a position facing each other means that the lengths LP and L of the convex portion 6 and the concave portion 7 are, for example, as shown in FIG.
It is particularly preferable that H be the same and the phases thereof be aligned and arranged. In addition, as shown in FIG.
The length LH of the concave portion is made larger than the length LP, and the convex portion 6 is arranged so as to be included in the concave portion 7, or as shown in FIG. Those facing each other are also included in the embodiment of the present invention.

In the present embodiment, the maximum width WB of the block B1 with the convex portion in the tire axial direction on the tread surface 2 is set.
1 and the protrusion amount WP of the convex portion 6 (WP / WB1), and the maximum width WB of the block B2 with the concave portion in the tire axial direction.
The ratio (WH / WB2) between 2 and the recess amount WH of the concave portion 7 is set to 0.04 to 0.15 in all cases. When the value of each ratio is less than 0.04, the effect of improving the performance on snow and the performance on ice is poor. Conversely, when the value exceeds 0.15, the rigidity of the block becomes uneven and causes uneven wear. In addition, the convex portion 6 tends to impede the drainage effect of the vertical groove G1 and reduce wet grip performance,
Further, regarding the concave portion 7, the reduction in the ground contact area of the block is too large, so that the wear resistance is likely to be adversely affected. From such a viewpoint, the ratio (WP / WB1) and the ratio (WH
/ WB2) is preferably 0.048 to 0.143, more preferably 0.06 to 0.09.

The ratio (LP / LB1) of the maximum circumferential length LB1 (shown in FIG. 1) of the block B1 with the convex portion to the maximum circumferential length LP of the convex portion 6 in the tire circumferential direction (LP / LB1). The ratio (LH / LB2) between the maximum length LB2 (shown in FIG. 1) of the block B2 in the tire circumferential direction and the length LH of the concave portion 7 in the tire circumferential direction is 0.3 to 0.4. . If the value of each of the ratios is less than 0.3, the convex portion 6 or the concave portion 7 is too small and is not enough to enhance the traveling performance on ice and snowy roads. B1, B
Since the other portions 2 are small, it is difficult to exhibit the above-mentioned traveling performance, and there is a possibility that uneven wear may be caused. From such a viewpoint, the ratio (LP / LB1) and the ratio (LH
/ LB2) is preferably 0.3 to 0.4, more preferably 0.33 to 0.36.

By arranging the convex portion 6 and the concave portion 7 at positions facing each other via the outer vertical groove 3b and limiting the size of the block B1 or B2, the block with convex portion B1, the concave portion 7 The wear resistance of the attached block B2 can be improved.

In this embodiment, the protrusion amount WP of the protrusion 6 and the recess amount WH of the recess 7 are substantially the same, and the length LP of the protrusion 6 and the length LH of the recess 7 are substantially the same.
Thereby, the outer vertical groove 3b exemplifies a groove having a substantially constant groove width on the tread surface 2. Such an outer vertical groove 3b does not hinder the flow of drainage in the vertical groove 3b, for example, on a wet road surface, and can sufficiently secure wet grip performance.

Further, the block with projections B1 extends from both edges of the projections 6 in the tire circumferential direction and crosses the inside of the block to divide the block with projections B1 into approximately three first sipes S1. , S1. The block B2 with concave portions extends from both edges of the concave portion 7 in the tire circumferential direction and traverses the inside of the block to divide the block B2 with concave portions into approximately three equal sipes S2, S2.
It has.

As a result, each of the convex portion 6 and the concave portion 7 can move independently of the other portion divided by siping when touching the road surface, and the snow column shearing force is further increased to increase the snow column. The running performance is further improved, and the edges of the sipes S1 and S2 scratch the ice surface, and suck up moisture into the sipes S1 and S2, thereby further improving the grip performance when running on the ice surface. Further, the first and second sipings S1 and S2 are each a block B1,
By dividing B2 into approximately three equal parts in the tire circumferential direction, it is possible to prevent a significant decrease in the rigidity of each block and unevenness in the rigidity of each part divided by siping, and thus to suppress deterioration of wear resistance. . In addition, each siping S1, S2
Can be formed in various shapes, for example, it is desirable to form it approximately in parallel with the groove edge line of the lateral groove 4b that is closest to and adjacent to it, and in this example, it forms a straight line. Each siping S1 and S2 may include not only a straight line but also a bent portion that is bent in a zigzag, wavy, or the like.

In the present embodiment, the protrusions 6
The recess 7 has groove edges Be1 and Be2 that are substantially parallel to the block vertical wall surface 5 on the tread surface 2. This allows
On the tread surface 2, the groove edge contour of the outer vertical groove 3b has a shape in which a part of the vertical groove 3 is moved outward in the tire axial direction at a position where the convex portion 6 and the concave portion 7 face each other. By forming the convex portion 6 and the concave portion 7 in such a shape, the respective edge components can be increased and the snow column shearing force can be enhanced. At the same time, the increase in the edge components caused by these increases on the icy road surface. It is also effective for improving grip performance.

Further, in the case of a recent heavy duty tire of a studless type, after use in winter, the tire is used as it is on a normal road surface from spring to summer of the following year, and its life is completed by the next winter season. The form is becoming general. Therefore, in accordance with such usage patterns,
After running in winter, the sipes S1, S2 and the recesses 7, etc., which lower the block rigidity, for further improving the wear resistance for dry road surfaces, are used during use, more specifically, outside vertical. It is desirable that the groove 3b be configured to disappear by about 50 to 60% of wear.

In this example, as shown in FIGS. 2A and 2B, the depth DS1 of the first sipe S1 and the depth DS2 of the second sipe S2 are both equal to the depth of the outer vertical groove 3b. GD, and the radial lengths DP and DH of the convex portions 6 and the concave portions 7 in the tire radial direction are each 50% or less of the groove depth of the outer vertical groove 3b. As described above, it is desirable that the depths DS1 and DS2 of the sipings S1 and S2 are larger than the lengths DP and DH of the convex portions 6 and the concave portions 7 in the tire radial direction. As a result, the convex portion 6 or the concave portion 7 can be flexibly moved by siping until completely disappeared by abrasion, and can contribute to the improvement of running performance on ice and snow roads to the end.

[0027]

EXAMPLES In order to confirm the effect of the present invention, a radial tire for heavy load having a tire size of 11R22.5 was trial-produced and tested on ice, snow, wet performance, uneven wear resistance and wear resistance. . The tire of the example was formed by the tread surface shown in FIGS.

The tread surface shown in FIG. 4 has five longitudinal grooves 3, and a central longitudinal groove 3a passing through the tire equator C is formed in a straight line along the tire circumferential direction, and the first longitudinal groove 3a is disposed outside the tire. The outer vertical groove 3b1 and the second outer vertical groove 3b2 arranged outside thereof are all formed in a zigzag shape. Lateral groove 4
Are formed to form six rows of blocks by bending as appropriate and connecting between the vertical grooves 3 and between the vertical grooves 3 and the tread edge E. The dimensions of each groove width 3, 4 and the like are as shown in FIG.

The block B1 with the convex portion is provided with the first block.
The protrusions 6 are arranged so as to protrude toward the outer vertical grooves 3b1, and the blocks B1 are arranged in the tire circumferential direction to form the first block row R1. The block B2 with concave portions is formed outside the first outer vertical groove 3b1 in the tire axial direction with the concave portions 7 facing the convex portions 6 of the block B1 with convex portions, so that the second block row R2 is formed. Is configured. Each of these blocks B1, B2
Is schematically shown in FIGS. 5A and 5B.

The convex portion 6 and the concave portion 7 face each other, and their respective positions in the circumferential direction of the tire coincide with each other. In addition, the convex portion 6 and the concave portion 7 of this example have edges Be1 and Be2 that are substantially parallel to the groove edge of the first outer vertical groove 3b1 other than the convex portion 6 and the concave portion 7. The portion sandwiched between the convex portion 6 and the concave portion 7 has a shape as if a part of the first outer vertical groove 3b1 has been moved outward in the tire axial direction. In addition, as shown in FIG. 5A, the block B1 with the convex portion is formed on the zigzag convex top portion T1 in which the block vertical wall surface 5 projects outward of the block B1 by zigzag of the vertical groove 3b1. Also, as shown in FIG.
The block vertical wall surface 5 is formed in a zigzag concave top T2 that is recessed inward of the block B1 by zigzag of the vertical groove 3b2. By forming the convex portions 6 and the concave portions 7 on such a block vertical wall surface 5, respectively, the effects of the convex portions 6 and the concave portions 7 are more remarkably exhibited.

Each of the blocks B1, B2 is substantially equally divided into three in the tire circumferential direction by first and second sipes S1, S2 extending from both circumferential edges of the convex portion 6 or the concave portion 7. Each siping S1, S2 is formed in a shape along the edge of the lateral groove closest to it.

For comparison, tires of the same size and the like of Comparative Examples 1 to 3 having tread surfaces shown in FIGS. 6 to 8 were also prototyped, and their performances were compared. Next, the contents of the test will be described.

(Performance on ice) The test tire was mounted on a rim (7.50
× 22.5) with rim assembled, filled with internal pressure 800 (kPa), mounted on all wheels of a 2 / 2-D vehicle (maximum loading capacity 10t), and locked on an ice plate from 30km / h By measuring the braking distance. The evaluation was performed using an index determined by the following equation. The higher the value, the better. Performance on ice = {(braking distance of Comparative Example 1) / (obtained braking distance)} × 100

(Snow Performance) Using a test vehicle equipped with the test tires described above, a pressed snow road surface having a thickness of 10.0 cm (temperature:-
13.5 ° C, ice temperature: -5.0 ° C, snow temperature: -8.0 ° C).
The evaluation focused on braking, acceleration, turning, etc. The results are represented by an index with the value of Comparative Example 1 being 100, and the larger the value, the better.

(Wet performance) The above test vehicle was used to measure the braking distance when the asphalt road surface having a water film of 0.3 cm was locked from a speed of 40 km / h. The evaluation was performed using an index determined by the following equation. The higher the value, the better. Wet performance = {(braking distance of comparative example 1) / (obtained braking distance)} × 100

(Uneven wear resistance) Using a test vehicle under the same conditions as described above, running on a general road and a highway for a total of 3000 km, uneven wear (heel-and-toe wear, The presence or absence of edge wear, one-sided wear, etc.) was visually observed.
It is indicated by an index of 00. The higher the value, the better.

(Abrasion Resistance Performance) After the uneven wear resistance test, the average depth of the longitudinal grooves of the test tire was determined, and the average depth was expressed as an index with Comparative Example 1 being 100. The higher the value, the better. Table 1 shows the test results.

[0038]

[Table 1]

[0039]

As described above, according to the first aspect of the present invention, the protruding portions and the concave portions are provided in the blocks adjacent to each other with the vertical groove therebetween, so that the edge component on the tread surface increases, and In addition to enhancing the running performance of the vehicle, the convex and concave portions can generate snow column shearing force within the vertical groove even when the groove is straight, and in combination with the snow column shearing force due to the lateral groove. Grip force during running on snowy roads can be greatly improved. In addition, as a result of the convex portions and the concave portions being arranged at positions facing each other via the vertical grooves, for example, it is possible to ensure a substantially constant groove width of the outer vertical grooves, which impedes drainage in the vertical grooves. The wet grip performance can be secured without performing. Thereby, the pneumatic tire of the present invention can improve on-ice performance, on-snow performance, wet performance, uneven wear resistance, and wear resistance in a well-balanced manner.

According to the second aspect of the present invention, the block with the convex portion is formed by cutting both ends in the circumferential direction of the vertical wall surface of the block by a slope inclined toward the inside of the block from the groove bottom side of the vertical groove toward the tread surface side. Due to the chipping, a convex portion is formed between the slopes, and as a result, a step surface connected to the slope can be formed on both sides of the convex portion. In addition, the block with the concave portion forms the concave portion by cutting out the middle portion of the vertical wall surface of the block in the tire circumferential direction by a slope inclined toward the inside of the block from the groove bottom side of the vertical groove toward the tread surface side, and as a result, On both sides of this slope, a stepped surface that continues to the vertical side of the block can be formed. By these step surfaces, the shear strength of the snow column in the vertical groove can be further enhanced, and the grip force on the snowy road is further improved.

According to the fourth aspect of the present invention, both the convex portion and the concave portion can move independently of both side portions in the tire circumferential direction at the time of contact with the ground, so that the snow column shearing force can be further increased to increase the snow column. The running performance is further improved, and the gripping performance during running on the ice surface can be further improved by the edge of the siping scratching the ice surface and sucking moisture into each siping. In addition, the first and the second provided in each block
The siping of each block divides each block into approximately three equal parts in the tire circumferential direction to prevent a significant decrease in block rigidity and unevenness in rigidity of each part divided by siping, thereby suppressing deterioration of wear resistance. sell.

According to the fifth aspect of the present invention, since the length of the convex portion and the concave portion in the tire radial direction is 40 to 50% of the depth of the vertical groove, the tire has completed running in winter, for example. It disappears later, and the wear resistance can be further improved for running on dry road surfaces.

According to a sixth aspect of the present invention, in the first siping and the second siping, the depth is greater than the length of the convex portion and the concave portion in the tire radial direction. The effects of the recesses can be effectively maintained until they disappear.

[Brief description of the drawings]

FIG. 1 is a development view of a tread surface showing an embodiment of the present invention.

FIG. 2 (A) is a perspective view of a block with a projection,
(B) is a perspective view of the block with a recess.

FIG. 3 is an enlarged schematic plan view showing a convex portion and a concave portion.

FIG. 4 is a development view of a tread pattern of a tire showing another embodiment of the present invention.

FIG. 5 (A) is a perspective view of the block with a convex portion,
(B) is a perspective view of the block with a recess.

FIG. 6 is a development view of a tread surface of a comparative example.

FIG. 7 is a development view of a tread surface of a comparative example.

FIG. 8 is a development view of a tread surface of a comparative example.

[Explanation of symbols]

 2 Tread surface 3 Vertical groove 4 Horizontal groove 5 Block vertical wall surface 6 Convex portion 7 Recess B1 Block with convex portion B2 Block with concave portion C Tire equator R1 First block row R2 Second block row S1 First siping S2 Second Siping SP, SH Slope

Claims (6)

[Claims] An air in which a plurality of block rows in which blocks are arranged in a tire circumferential direction are formed on a tread surface by providing a vertical groove extending in a tire circumferential direction and a plurality of horizontal grooves crossing the vertical groove. A tire with a protrusion, wherein the block row is a first block having a protrusion provided with a protrusion protruding toward the vertical groove at a substantially middle position in a circumferential direction of a vertical wall surface of the block facing the vertical groove. A block row, a block with a concave portion provided with a concave portion recessed inside the block at a substantially middle position in the circumferential direction of the vertical wall surface of the block, and the concave portion faces the convex portion of the block with the convex portion via a vertical groove. And a ratio (WP / WP) between the maximum width WB1 of the block with the protrusion in the tire axial direction and the protrusion amount WP of the protrusion on the tread surface.
WB1) and the ratio (WH / WB) between the maximum width WB2 of the block with the concave portion in the tire axial direction and the concave amount WH of the concave portion.
2) is set to 0.04 to 0.15, and the ratio (LP / LB) of the maximum circumferential length LB1 of the block with the convex portion to the maximum circumferential length LP of the convex portion in the tire circumferential direction.
1) and the ratio (L) of the maximum length LH in the tire circumferential direction of the block with the recess to the length LB2 of the recess in the tire circumferential direction.
H / LB2) is 0.3 to 0.4. 2. The block with protrusions is formed by cutting out both ends of the block vertical wall surface in the circumferential direction with a slope inclined from the bottom of the vertical groove toward the tread surface toward the inside of the block. The convex portion is formed between the slopes, and the block with the concave portion inclines a middle portion of the block vertical wall surface in the circumferential direction from the groove bottom side of the vertical groove toward the tread surface side into the block. The concave portion is formed by cutting out by a slope.
The pneumatic tire as described. 3. The pneumatic tire according to claim 1, wherein the vertical groove has a substantially constant groove width on a tread surface. 4. The projection-equipped block includes a first siping extending from both circumferential edges of the projection and crossing the inside of the block to divide the projection-equipped block into approximately three equal parts. The said recessed block is provided with the 2nd siping which divides the said block with a recess substantially by extending from both edges of the said recessed part in the circumferential direction, and traversing the inside of a block. The pneumatic tire according to any one of the above. 5. The method according to claim 1, wherein the convex portion and the concave portion have a length in a tire radial direction of 40 to 50% of a depth of the vertical groove. Pneumatic tire. 6. A depth of the first siping and the second siping is greater than a length of the convex portion and the concave portion in the tire radial direction and is not more than 60% of a depth of the vertical groove. The pneumatic tire according to claim 4, wherein: