JP2010137770A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the traction performance and the lateral grip performance during off-road running. <P>SOLUTION: A pneumatic tire includes inner lateral grooves 3 extending from an inner tread edge Ti at an angle θ1 of 80-90° with respect to the tire circumferential direction in mounting on a vehicle, first inclined grooves 4 extending from inner ends 3i of the inner lateral grooves 3 at an angle θ2 of 45-70° with respect to the tire axial direction in the reverse direction with respect to the rotational direction R toward an outer tread edge To, and second inclined grooves 5 extending from the inner ends 3i of the inner lateral grooves 3 in the reverse direction with respect to the first inclined grooves 4 at an intersection angle α of 70-110° with respect to the first inclined grooves 4 toward the outer tread edge To side. Thus, an outer block row 10 including a plurality of rectangular block rows 7 in which rectangular blocks 6 separated by the first inclined grooves 4 and the second inclined grooves 5 and inclined obliquely are arranged so as to be spaced with each other in the circumferential direction is provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pneumatic tire suitable for running on rough terrain that can improve traction performance, lateral grip performance, and the like in rally, dirt trials, and the like.

For example, in the case of pneumatic tires for rough terrain that are used for off-road driving, the traction performance for gripping the road surface firmly and transmitting the driving force to the road surface is suppressed, and the skidding of the tire during turning is suppressed. Therefore, it is necessary to achieve a high level of lateral grip performance. For this reason, conventionally, various proposals have been made regarding the block shape, groove shape, etc. in the tread pattern (see, for example, Patent Documents 1 and 2 below).
Japanese Patent Laid-Open No. 11-268506 JP 2001-180230 A

  In order to make the two performances compatible, it is necessary to advantageously use the edge of the block in the tread pattern according to the running condition. However, the conventional tread pattern has room for further improvement in the arrangement of the edges. In particular, the side grip performance is low when a slip angle is given to the tire, and the side slip is relatively large.

  The present invention has been devised in view of the above circumstances, and is divided into a first inclined groove and a second inclined groove extending at a specific inclination angle in a region outside the vehicle of the tread portion and obliquely. Provided is a pneumatic tire capable of improving traction performance, lateral grip performance, etc. at a high level on the basis of including a plurality of rectangular block rows in which rectangular blocks inclined in the circumferential direction are spaced apart in the circumferential direction This is the main purpose.

  The invention according to claim 1 of the present invention is a pneumatic tire having a block pattern that is asymmetrical with respect to the tire equator, and in which the mounting direction and the rotational direction of the vehicle are specified. An inner lateral groove extending from the inner tread edge facing the inside of the vehicle at an angle of 80 to 90 degrees with respect to the tire circumferential direction and spaced apart in the tire circumferential direction, and from the inner end of the inner lateral groove to the tire axial direction A first inclined groove extending from the inner end of the inner lateral groove to an outer tread edge side at an angle of 45 to 70 degrees, opposite to the rotational direction and facing the vehicle outer side when mounted on the vehicle, By providing a second inclined groove having a reverse direction and an angle of intersection with the first inclined groove of 70 to 110 degrees and extending toward the outer tread edge side, an outer side than the inner end of the inner lateral groove is provided. In the region, the first inclined groove and the first Inclined groove and with segmented and rectangular block which is inclined obliquely is characterized in that it comprises an outer block row including a plurality of rows of rectangular block rows which are spaced in the circumferential direction of the.

  According to a second aspect of the present invention, the rectangular block has a ratio (b / a) between a block length b along the first inclined groove and a block length a perpendicular to the first inclined groove. Is a pneumatic tire according to claim 1.

  According to a third aspect of the present invention, in the rectangular block of the rectangular block row formed on the innermost side of the vehicle, the distance in the tire axial direction from the center of gravity of the tread surface to the tire equator is 5% or less of the tread contact width. A pneumatic tire according to claim 1 or 2.

  According to a fourth aspect of the present invention, the inner lateral groove terminates in front of the tire equator without reaching the tire equator, and the tire axial distance from the intersection of the inner lateral groove and the first inclined groove to the tire equator. The pneumatic tire according to any one of claims 1 to 3, wherein the tire is 20% or more and 25% or less of a tread contact width.

  In the invention according to claim 5, the outer block row includes a large block having the largest tread area and a small block having the smallest tread area, and the tread area of the small block is 90% of the tread area of the large block. The pneumatic tire according to any one of claims 1 to 4, which is the above.

  In the invention according to claim 6, the tread portion is provided with an inner circumferential groove continuous in the tire circumferential direction at a position of 7 to 15% of the tread contact width from the inner tread edge. The pneumatic tire according to any one of claims 1 to 5, wherein a longitudinal block having a circumferential length larger than an axial length is divided between an inner circumferential groove and an inner tread edge.

  According to a seventh aspect of the present invention, there is provided an inner sub-groove extending in the tire axial direction from the inner circumferential groove to the first inclined groove or the second inclined groove between the inner lateral grooves adjacent in the tire circumferential direction. The pneumatic tire according to any one of claims 1 to 6, wherein is formed.

  The pneumatic tire of the present invention includes an inner lateral groove extending at an angle of 80 to 90 degrees with respect to the tire circumferential direction from the inner tread edge facing the inside of the vehicle when mounted on the vehicle and spaced apart in the tire circumferential direction. A first inclined groove extending from the inner end of the inner lateral groove to the outer tread edge at an angle of 45 to 70 degrees with respect to the tire axial direction and opposite to the tire rotation direction; A second inclined groove extending in the direction opposite to the first inclined groove and extending to the outer tread edge side at an intersecting angle of 70 to 110 degrees with the first inclined groove is provided. As a result, a rectangular block row in which diagonally inclined rectangular blocks divided by the first inclined groove and the second inclined groove are spaced apart in the circumferential direction in a region outside the inner end of the inner lateral groove. An outer block row including a plurality of rows is formed.

  Such a pneumatic tire exhibits high traction performance when the block sufficiently grips the road surface during off-road running such as in a muddy ground or a sandy road. In particular, the inner lateral groove extending substantially in the tire axial direction provides excellent traction performance when traveling straight. Also, during turning where a large slip angle is given to the tire, the edge of the rectangular block inclined obliquely in the pneumatic tire on the outside and outside of the vehicle is brought close to the direction perpendicular to the side slip direction of the vehicle. be able to. As a result, a high frictional force is exerted on the road surface during turning, and as a result, a high side grip performance can be obtained while suppressing a side slip.

  As described above, the pneumatic tire of the present invention can improve the traction performance and the lateral grip performance at a high level.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic top view of a vehicle M in which the pneumatic tire 1 of the present embodiment is mounted on four wheels, and FIG. 2 is a plan view of the tread portion 2 of the pneumatic tire mounted on the left wheel 1L. FIG. In FIG. 1, the vehicle M is a front-wheel steering four-wheeled vehicle, and the symbol F indicates the vehicle traveling direction (front).

  In the pneumatic tire 1 of the present embodiment, the mounting direction to the vehicle M and the rotation direction are specified. That is, in order to maximize the effect of the block pattern formed on the tread portion 2, the tire is designated with its rotational direction R and different for the right wheel 1R or the left wheel 1L of the vehicle M. . That is, the pneumatic tire 1 of the present embodiment includes a right wheel 1R and a left wheel 1L. Further, the direction of mounting on the vehicle or the like is displayed, for example, on the sidewall portion of the tire 1 by characters or patterns (not shown).

  The tread portion 2 includes an inner tread portion 2i that forms a region from the inner tread edge Ti facing the inside of the vehicle M to the tire equator C when mounted on the vehicle, and an outer tread edge To facing the vehicle outer side. And an outer tread portion 2o forming a region from the tire equator C to the tire equator C. In order to maximize the performance of the block pattern, the inner tread portion 2i and the outer tread portion 2o are formed in an asymmetric pattern with respect to the tire equator C.

  Here, each of the tread edges Ti and To is a vehicle inner side and a vehicle outer side when the tire is assembled on a normal rim and filled with a normal internal pressure and is loaded with a normal load and grounded to a plane with a camber angle of 0 degrees. In each of these, it is defined as the ground contact end on the outermost side in the tire axial direction. The tire axial distance between the tread edges Ti and To is defined as a tread ground contact width TW.

  The “regular rim” is a rim determined for each tire in the standard system including the standard on which the tire is based. For example, “Standard Rim” for JATMA and “Design Rim” for TRA. For ETRTO, use "Measuring Rim".

  Furthermore, “normal internal pressure” is the air pressure that each standard defines for each tire in the standard system including the standard on which the tire is based, and is “maximum air pressure” for JATMA, and “TIRE” for TRA. The maximum value described in “LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES”, or “INFLATION PRESSURE” in the case of ETRTO.

  Furthermore, the “regular load” is a load determined by each standard for each tire in the standard system including the standard on which the tire is based, and is “maximum load capacity” for JATMA and “TIRE” for TRA. The maximum value described in “LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES”, or “LOAD CAPACITY” in the case of ETRTO. In addition, when neither standard exists, a tire manufacturer's recommendation value is applied.

  As shown in FIG. 2, the tread portion 2 has an inner side that is spaced apart from the inner tread edge Ti at an angle θ1 of 80 to 90 degrees with respect to the tire circumferential direction on the tire equator C side and in the tire circumferential direction. A lateral groove 3 and a first inclined groove 4 extending from the inner end 3i of the inner lateral groove 3 to an outer tread edge To at an angle θ2 of 45 to 70 degrees with respect to the tire axial direction and in a direction opposite to the rotational direction R. First, the inner groove 3 extends in the direction opposite to the first inclined groove 4 from the inner end 3i of the inner horizontal groove 3 and inclines toward the outer tread edge To when the intersecting angle α with the first inclined groove 4 is 70 to 110 degrees. Two inclined grooves 5 are provided.

  In the pneumatic tire 1 of the present embodiment, the first inclined groove 4 and the second inclined groove 5 are divided in the region outside the vehicle from the inner end 3i of the inner lateral groove 3 by the grooves 3 to 5 described above. In addition, an outer block row 10 including a plurality of rectangular block rows 7 in which the rectangular blocks 6 inclined obliquely are spaced in the circumferential direction, three rows in this embodiment, is formed. In the pneumatic tire 1 having such a block pattern, the road surface is sufficiently gripped by the edge of the rectangular block 6 or the lateral groove 3 in off-road traveling such as muddy ground and sandy road, and has high traction performance. Demonstrated.

  An angle θ1 of the inner lateral groove 3 with respect to the tire circumferential direction is set to 80 to 90 degrees. If the angle θ1 is less than 80 degrees, sufficient traction performance cannot be obtained during straight traveling. In particular, when the tire is attached to the vehicle M with a negative camber, the ground pressure of the inner tread portion 2i increases when going straight, and thus such a problem is likely to occur. When the angle θ1 of the inner lateral groove 3 is less than 90 degrees, the inner lateral groove 3 may be inclined in the same direction as the tire rotation direction R or in the opposite direction.

  The lateral grooves 3 in this embodiment are formed as straight grooves, but may be curved grooves that are curved or bent. In the case of such a curved groove, the angle θ1 of the inner groove is measured as an angle formed by a straight line connecting both ends of the groove center line and a tire circumferential line.

  Further, the off-road road surface has a smaller μ than the dry asphalt road surface and is very slippery. For this reason, a very large slip angle of about 45 to 70 degrees can occur during high speed traveling. In the pneumatic tire 1 of the present invention, when such a large slip angle occurs, the edge 6e along the first inclined groove 4 of the rectangular block 6 is effectively used as a resistance against the road surface. The angle [theta] 2 of the inclined groove 4 is set to 45 to 70 [deg.] Larger than the conventional angle.

  FIG. 3 is a perspective view from above of the ground contact surface shape at the time of turning when the tire 1 has a large slip angle δ. At the time of turning, in the pneumatic tire 1 outside the turning (for example, the left wheel 1L in the right turning state with the handle turned to the right), a large lateral force f is applied to the block edge 6e along the first inclined groove 4 of the rectangular block 6. Works. In the pneumatic tire 1 of the present embodiment, the block edge 6e can be grounded in a direction substantially perpendicular to the lateral force f, that is, in a direction substantially perpendicular to the side slip direction of the vehicle M. Thereby, in the pneumatic tire of this embodiment, high lateral grip performance is obtained even on a slippery off-road surface, and excellent turning performance can be exhibited.

  Here, when the angle θ2 of the first inclined groove 4 is less than 45 degrees or more than 70 degrees, the longitudinal direction of the block edge 6e of the rectangular block 6 is the side slip of the vehicle when turning on the off-road road surface. Since it approaches a direction parallel to the direction, a sufficient lateral grip force cannot be obtained. In a more optimal embodiment, the angle θ2 is preferably 60 degrees or less, more preferably 55 degrees or less.

  Further, the crossing angle α between the second inclined groove 5 and the first inclined groove 4 needs to be 70 to 110 degrees. When the crossing angle α exceeds 110 degrees, the rigidity in the vicinity of the corner portion 6A on the rotation direction first arrival side of the rectangular block 6 is locally reduced, and stress at the time of turning concentrates on the corner portion 6A. Wear occurs. On the contrary, when the crossing angle α is less than 70 degrees, the rigidity of the corner portion 6B of the rectangular block 6 facing the crossing angle α is locally reduced, and there is a possibility that the same problem as described above may occur.

  The second inclined groove 5 of the present embodiment communicates with and terminates in the first inclined groove 4 on the outermost tread edge To side where the second inclined groove 5 communicates. This prevents a small triangular land portion from being formed at the outer tread edge To.

  The rectangular block 6 has a ratio (b / a) between the block length b along the first inclined groove 4 and the block length a perpendicular to the first inclined groove 4 of 1.0 or more. In particular, it is desirably 1.1 or more, more preferably 1.2 or more. That is, it is particularly desirable that the rectangular block 6 has a vertically long shape along the first inclined groove 4.

  Such a rectangular block 6 ensures a longer block edge 6e along the first inclined groove 4 and further improves the lateral grip performance during turning. However, if the ratio (b / a) is too large, there is a risk of insufficient traction or a decrease in lateral grip force when going straight due to a decrease in rigidity in the tire circumferential direction of the rectangular block 6. From such a viewpoint, the ratio (b / a) is preferably 1.6 or less, more preferably 1.5 or less.

  As a more preferred embodiment, in this embodiment, all the rectangular block rows 7 included in the outer block row 10 are each composed of rectangular blocks 6 having substantially the same tread surface area. Thus, by making the tread surface area of the rectangular block 6 that is in strong contact with the road surface when turning substantially the same, the unevenness of the contact pressure between the blocks is eliminated, and the rectangular block 6 is evenly worn. Is possible. The fact that the tread area of the rectangular blocks 6 is substantially equal includes at least a mode in which the difference between the tread areas is 5% or less in view of pitch variation and the like.

  The outer block row 10 of the present embodiment is composed of the above-described three rectangular block rows 7 and the one trapezoid block row 9 in which the trapezoidal blocks 8 are arranged on the outermost side of the vehicle and arranged in the tire circumferential direction. It is formed. That is, the outer block row 10 of the present embodiment includes four block rows. At the time of turning, the grounding center is located on the vehicle outer side than the tire equator C of the tread portion 2, and the outer block row 10 is mainly in contact with the road surface. By including it, more block edges can be grounded when turning and sufficient lateral grip performance can be exhibited.

  In order to prevent uneven wear in the outer block row 10, the tread area of the trapezoidal block 8 is preferably approximated to the tread area of the rectangular block 6. For example, the trapezoidal block 9 of the present embodiment is a large block having the largest tread surface area in the outer block row 10. On the other hand, the rectangular block 6 is a small block having the smallest tread area in the outer block row 10. In the outer block row 10, in order to effectively prevent uneven wear of each of these blocks 6 and 8, the tread area of the small block (rectangular block 6) is equal to the tread area of the large block (trapezoidal block 9). It is desirable to set it to 90% or more, more preferably 95% or more.

  In addition, the rectangular block 6 of the rectangular block row 7i formed on the innermost side of the outer block row 10 has a tire axial direction distance L1 from the center of gravity G of the tread surface 6a to the tire equator C so that the tread contact width TW. It is desirable to be provided at a position of 5% or less. Thus, by arranging the center of gravity G of the rectangular block 6 in the vicinity of the tire equator C, the pattern rigidity of the central portion of the tread is improved, which in turn helps to improve the wear resistance and the straight running stability.

  Various improvements can also be made on the inner tread portion 2i. For example, the inner lateral groove 3 is preferably terminated before reaching the tire equator C. When the inner lateral groove 3 extends beyond the tire equator C, the area occupied by the outer block row 10 is reduced, and as a result, the lateral grip force may be reduced.

  In a preferred embodiment, the tire axial distance L2 from the intersection P between the inner lateral groove 3 and the first inclined groove 4 to the tire equator C is preferably 20% or more and 25% or less of the tread contact width TW. . By setting the distance L2 in this way, the running performance on both hard roads and soft roads can be improved in a well-balanced manner even on rough terrain. Moreover, the outer block row 10 including at least three rows, more preferably four rows of rectangular blocks 7 having sufficient block stiffness can be formed without reducing the pattern stiffness of the inner tread portion 2i. In addition, the intersection P of the inner side groove | channel 3 and the 1st inclination groove | channel 4 is defined as an intersection of each groove | channel centerline, as FIG. 2 shows.

  Further, with respect to the inner tread portion 2i, one inner circumferential groove 11 continuous in the tire circumferential direction is formed at a position separating the tire axial distance L3 of 7 to 15% of the tread contact width TW from the inner tread edge Ti. It is desirable to provide (position the groove center line of the inner circumferential groove 11). And it is desirable to form between the inner circumferential groove 11 and the inner tread edge Ti, a longitudinal block 12 which is divided by the inner lateral groove 3 and whose tire circumferential direction length is larger than the axial length.

  When the vehicle M turns, the tire on the inside of the turn (for example, the right wheel 1R in the right turn state with the steering wheel turned to the right) has more contact with the inner tread portion 2i from the road surface and is dragged to the outside of the turn. At this time, the vertically long block 12 provided in the inner tread portion 2i serves as a resistance when dragged to the outside of the vehicle, and helps to prevent a side slip. In order to maximize such an effect, it is desirable that the inner circumferential groove 11 extends linearly in parallel with the tire circumferential direction. Similarly, the ratio (c / d) between the tire circumferential direction length c and the tire axial direction length d of the vertically long block 12 is preferably 1.5 or more, more preferably 2.0 or more, and preferably Is 5.0 or less, more preferably 4.0 or less.

  Further, in the tire axial direction from the inner circumferential groove 11 to the first inclined groove 4 or the second inclined groove 5 between the inner lateral grooves 3 and 3 adjacent in the tire circumferential direction, more preferably at an intermediate position therebetween. The sub transverse groove 14 can be formed. The sub lateral groove 14 in the present embodiment extends in parallel with the inner lateral groove 3. Due to the sub-grooves 14 in the inside, a horizontally-long trapezoidal block 15 whose tire axial direction length is larger than the tire circumferential length is divided in the inner tread portion 2i on the tire equator C side of the vertically long block 12. Is done. The trapezoidal block 15 in the inside ensures a sufficient edge component in the tire axial direction in the inner tread portion 2i, and helps to obtain high traction during straight running.

  The groove widths GW1 to GW3 and the groove depths of the inner groove 3, the first inclined groove 4 and the second inclined groove 5 are not particularly limited. For example, sufficient traction performance on a soft road surface may be deteriorated. From such a viewpoint, the groove widths GW1 to GW3 are preferably 5 mm or more, more preferably 8 mm or more. The groove depth of the lateral grooves 3 and the inclined grooves 4 to 5 is preferably 10 mm or more.

  On the other hand, if the groove widths GW1 to GW3 and the groove depths of the inner lateral groove 3, the first inclined groove 4 and the second inclined groove 5 are too large, the pattern rigidity is lowered and the rubble path or the hardened hard There is a risk that sufficient traction performance may not be obtained on soil roads. From such a viewpoint, the groove widths GW1 to GW3 are preferably 15 mm or less, more preferably 12 mm or less. Similarly, the groove depth is preferably 11.5 mm or less.

  In particular, it is desirable to make the groove width GW2 of the first inclined groove 4 larger than the groove width GW3 of the second inclined groove 5. Thereby, the lateral grip force at the time of turning further improves.

  As mentioned above, although embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it can implement in a various aspect.

  Pneumatic tires (size: 205 / 65R15) having the specifications shown in Table 1 were each prototyped, and traction performance, lateral grip performance, and the like were evaluated for each test tire. In addition, as for an Example and a comparative example, all the parts which are not described in Table 1 are the same.

  In the test, each tire was attached to all wheels of a four-wheel drive vehicle (2000cc), and the dirt test course of 2km per lap was run at high speed for 4 laps. Performance, braking performance and steering wheel responsiveness were each evaluated by the 5-point method (larger values are better). In addition, the wear state of the outer block row after the test run was observed with the naked eye. The vehicle has a negative camber and its angle is 2 degrees.

  The traction performance was evaluated mainly with respect to driving during straight running and deceleration. As for the side grip performance, the initial responsiveness during turning, the amount of side slip during turning, the feeling of rising grip at the corner exit, and the like were comprehensively evaluated. The braking performance was evaluated based on the ease of braking, and the steering response was evaluated based on the response when steering was started.

  Table 1 shows the test results.

テストの結果、実施例の空気入りタイヤは、トラクション性及び横グリップ性能などが大幅に向上していることが確認できた。

As a result of the test, it was confirmed that the pneumatic tires of the examples were greatly improved in traction and lateral grip performance.

1 is a schematic top view showing a state in which a pneumatic tire according to an embodiment is mounted on a vehicle. It is a plane development view of the left wheel. It is the figure which saw through from the top the contact surface of the pneumatic tire at the time of turning.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 2i Inner tread part 2o Lateral groove 4 in outer tread part 3 First inclined groove 5 Second inclined groove 6 Rectangular block 7 Rectangular block row 8 Trapezoid block 9 Trapezoid block row 10 Outer block row Ti Inner tread edge To Outer tread edge M Vehicle

Claims (7)

A pneumatic tire having a block pattern that is asymmetrical with respect to the tire equator, and in which the mounting direction on the vehicle and the rotation direction are specified,
An inner lateral groove extending at an angle of 80 to 90 degrees with respect to the tire circumferential direction from the inner tread edge facing the inside of the vehicle when mounted on the vehicle and spaced in the tire circumferential direction;
A first inclined groove extending from an inner end of the inner lateral groove at an angle of 45 to 70 degrees with respect to the tire axial direction, opposite to the rotational direction and toward the outer tread edge side facing the outside of the vehicle when mounted on the vehicle;
There is provided a second inclined groove extending from the inner end of the inner lateral groove in a direction opposite to the first inclined groove and extending to the outer tread edge side at an intersection angle of 70 to 110 degrees with the first inclined groove. By being
A rectangular block in which rectangular blocks, which are divided by the first inclined groove and the second inclined groove and are inclined obliquely, are provided in a region outside the inner end of the inner lateral groove in the circumferential direction. A pneumatic tire comprising an outer block row including a plurality of rows.   The rectangular block has a ratio (b / a) between a block length b along the first inclined groove and a block length a in a direction perpendicular to the first inclined groove of 1.0 to 1.6. The pneumatic tire according to claim 1.   The pneumatic block according to claim 1 or 2, wherein the rectangular block of the rectangular block row formed on the innermost side of the vehicle has a tire axial distance from the center of gravity of the tread surface to the tire equator of 5% or less of the tread contact width. tire. The inner lateral groove terminates in front of it without reaching the tire equator,
The pneumatic tire according to any one of claims 1 to 3, wherein a distance in the tire axial direction from an intersection of the lateral groove and the first inclined groove to the tire equator is 20% or more and 25% or less of the tread contact width. tire. The outer block row includes a large block having the largest tread area and a small block having the smallest tread area,
The pneumatic tire according to any one of claims 1 to 4, wherein a tread area of the small block is 90% or more of a tread area of the large block. The tread portion is provided with an inner circumferential groove continuous in the tire circumferential direction at a position of 7 to 15% of the tread contact width from the inner tread edge, and the inner circumferential groove and the inner tread. The pneumatic tire according to any one of claims 1 to 5, wherein a vertically long block having a circumferential length larger than an axial length is divided between the edge and the edge.   7. An inner sub-groove extending in the tire axial direction from the inner circumferential groove to the first inclined groove or the second inclined groove is formed between adjacent inner grooves in the tire circumferential direction. The pneumatic tire according to any one of the above.

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