JP2018030419A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of improving on-ice performance.SOLUTION: The pneumatic tire comprises: two 1st second lug grooves 32, both ends of which are connected to a center main groove 21 and a second main groove 22; a second block 12 which is partitioned by the center main groove 21, the second main groove 22 and the two 1st second lug grooves 32; a 2nd second lug groove 33, one end of which is connected to the second main groove 22 and the other end of which terminates in the second block 12; and a pair of circumferentially inclined narrow grooves 40 extending in an inclined direction with respect to a tire circumferential direction, both ends of which are connected to the 1st second lug grooves 32 and the 2nd second lug groove 33. The center main groove 21 and the second main groove 22 have, at a groove wall 23 adjacent to the second block 12, a long part 24 and a short part 25 respectively which are different in relative length from each other and are arranged alternately in the tire circumferential direction, where an inclined direction of the long part 24 with respect to the tire circumferential direction is opposite to the inclined direction of the circumferentially inclined narrow grooves 40.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire.

  In so-called studless tires that require driving performance on ice and snow, the frictional force is increased by using flexible rubber, and the groove on the tread is devised to improve the performance on ice and snow. . For example, in the pneumatic tire described in Patent Document 1, in order to improve the turning performance and the limit behavior at the time of turning on an icy and snowy road in a well-balanced manner, the outer middle block defined by the outer middle lateral groove has one end on the outer shoulder. A groove connected to the main groove and having the other end terminating in the outer middle block is provided, and the groove and the outer middle lateral groove are alternately arranged in the tire circumferential direction. Moreover, in the pneumatic tire described in patent document 2, in order to improve on-snow performance without sacrificing running performance on a dry road surface, a lateral groove is provided between the first main groove and the second main groove. Those communicating with the first main groove and those not communicating with the first main groove are alternately arranged in the tire circumferential direction.

Japanese Patent No. 5629286 Japanese Patent No. 4471310

  Here, in recent years, in the development of studless tires, it is increasingly important to improve the performance on snow and the performance on ice. In particular, with respect to performance on ice, there are increasing demands for improving braking performance, turning performance, and the like. In general, it is effective to reduce the groove area in the tread pattern to improve the turning performance on ice. However, to improve the braking performance on ice, it is effective to increase the groove area. For this reason, it has been very difficult to balance these performances and improve the overall performance on ice.

  This invention is made | formed in view of the above, Comprising: It aims at providing the pneumatic tire which can improve performance on ice.

  In order to solve the above-described problems and achieve the object, a pneumatic tire according to the present invention includes a first main groove extending in the tire circumferential direction, and a second main groove extending in the tire circumferential direction and adjacent to the first main groove. A main groove, a first lug groove extending in the tire width direction and having both ends connected to the first main groove and the second main groove, and both sides in the tire width direction are the first main groove and the second main groove A block that is partitioned by a groove and that is divided by the two first lug grooves on both sides in the tire circumferential direction, extends in the tire width direction, and has one end connected to the second main groove and the other end in the block A second lug groove that terminates in the tire, extends in a direction inclined in the tire width direction with respect to the tire circumferential direction, is connected at both ends to the first lug groove and the second lug groove, and defines the block Two of the first lug grooves and the second lug A pair of circumferentially inclined narrow grooves disposed between each of the two, and the pair of circumferentially inclined narrow grooves are different from each other in a position where they are connected to the second lug groove in the tire width direction. The first main groove and the second main groove are formed on the groove wall adjacent to the block so that the inclination directions in the tire width direction with respect to the tire circumferential direction are opposite to each other and have a relative length. And the first main groove and the second main groove are different from each other in the tire width direction with respect to the tire circumferential direction. The inclination direction of the long portion is a direction opposite to the inclination direction in the tire width direction with respect to the tire circumferential direction of the circumferential inclined narrow groove.

  In the pneumatic tire, it is preferable that the inclined slant groove in the circumferential direction has an inclination angle α with respect to the tire circumferential direction in a range of 10 ° ≦ α ≦ 70 °.

  In the pneumatic tire, it is preferable that the elongated portions of the first main groove and the second main groove have an inclination angle β with respect to the tire circumferential direction in a range of 5 ° ≦ β ≦ 40 °.

  The said pneumatic tire WHEREIN: It is preferable that the said circumferential direction inclination fine groove has two or more places of the said circumferential direction inclination fine groove where the groove depth changes.

  In the pneumatic tire described above, it is preferable that the amount of change Dg at the change point of the groove depth is in a range of 2.0 mm ≦ Dg ≦ 6.0 mm.

  The said pneumatic tire WHEREIN: It is preferable that the said circumferential direction inclination fine groove has two or more places of the said circumferential direction inclination fine groove where the groove width changes.

  In the pneumatic tire, it is preferable that the amount of change Wg at the change point of the groove width is in a range of 0.5 mm ≦ Wg ≦ 5.0 mm.

  In the pneumatic tire, it is preferable that the first lug groove has one or more change points of the groove width.

  In the pneumatic tire, the first lug groove preferably has a change amount W1 at a change point of the groove width in a range of 1.0 mm ≦ W1 ≦ 3.0 mm.

  In the pneumatic tire, it is preferable that the second lug groove has one or more change points of the groove width.

  In the pneumatic tire, the second lug groove preferably has a change amount W2 at a change point of the groove width in a range of 0.5 mm ≦ W2 ≦ 2.5 mm.

  The pneumatic tire according to the present invention has an effect that the performance on ice can be improved.

FIG. 1 is a plan view showing a tread surface of a pneumatic tire according to an embodiment. FIG. 2 is a detailed view of part A of FIG. FIG. 3 is a detailed view of part B of FIG. FIG. 4 is a cross-sectional view taken along line EE in FIG. FIG. 5 is a detailed view of part C of FIG. FIG. 6 is a detailed view of a portion D in FIG. FIG. 7 is a detailed view of the first second lug groove shown in FIG. FIG. 8 is a detailed view of the second second lug groove shown in FIG. FIG. 9A is a chart showing the results of a performance test of a pneumatic tire. FIG. 9B is a chart showing the results of the performance test of the pneumatic tire. FIG. 9C is a chart showing the results of the performance test of the pneumatic tire.

  Hereinafter, an embodiment of a pneumatic tire according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be replaced by those skilled in the art and can be easily conceived, or substantially the same.

  In the following description, the tire width direction means a direction parallel to the rotation axis of the pneumatic tire, the inner side in the tire width direction means the direction toward the tire equator line in the tire width direction, and the outer side in the tire width direction means the tire width. The direction opposite to the direction toward the tire equator line. Further, the tire radial direction means a direction orthogonal to the tire rotation axis, and the tire circumferential direction means a direction rotating around the tire rotation axis.

  FIG. 1 is a plan view showing a tread surface of a pneumatic tire according to an embodiment. A pneumatic tire 1 shown in FIG. 1 is provided with a tread portion 2 at the outermost portion in the tire radial direction, and the surface of the tread portion 2, that is, a vehicle on which the pneumatic tire 1 is mounted (not shown). The portion that comes into contact with the road surface during travel is formed as a tread surface 3. A plurality of circumferential main grooves 20 extending in the tire circumferential direction and lug grooves 30 extending in the tire width direction are formed on the tread surface 3, and the tread surface 3 includes the tread surface 3 and the tread surface 3. A plurality of blocks 10 that are land portions are formed on the surface 3.

  Specifically, four circumferential main grooves 20 are formed side by side in the tire width direction, and a center main groove 21 that is two first main grooves located on both sides of the tire equator line CL in the tire width direction. The second main groove 22, which is two second main grooves that are adjacent to the center main groove 21, are provided on the outer sides in the tire width direction of the two center main grooves 21. The lug groove 30 includes a center lug groove 31 positioned between the two center main grooves 21, a first second lug groove 32 positioned between the adjacent center main groove 21 and the second main groove 22, and A second second lug groove 33 and a shoulder lug groove 34 located on the outer side in the tire width direction of the second main groove 22 are provided. The circumferential main groove 20 here has a groove width in the range of 3.0 mm to 10.0 mm, and a groove depth in the range of 8.0 mm to 9.5 mm. The lug groove 30 has a groove width in the range of 1.5 mm or more and 8.0 mm or less, and a groove depth in the range of 5.0 mm or more and 9.0 mm or less.

  Among the plurality of lug grooves 30, the center lug groove 31 is formed extending in the tire width direction between the two center main grooves 21, and both ends thereof are connected to the center main groove 21. The first second lug groove 32 is formed to extend in the tire width direction between the adjacent center main groove 21 and the second main groove 22, and an end portion on the inner side in the tire width direction is connected to the center main groove 21. The outer end in the tire width direction is connected to the second main groove 22. Further, the second second lug groove 33 is formed to extend in the tire width direction between the adjacent center main groove 21 and the second main groove 22, and the outer end portion in the tire width direction is connected to the second main groove 22. An end portion on the inner side in the tire width direction terminates in a second block 12 described later. The second second lug grooves 33 and the first second lug grooves 32 are alternately arranged in the tire width direction at substantially the same intervals in the tire circumferential direction. The shoulder lug groove 34 is formed to extend in the tire width direction at a position on the outer side in the tire width direction of the second main groove 22, and an end portion on the inner side in the tire width direction is connected to the second main groove 22. Specifically, the shoulder lug groove 34 is disposed on each of the first second lug groove 32 and the second second lug groove 33 extending outward in the tire width direction.

  The lug grooves 30 are each curved in the tire circumferential direction or inclined while extending in the tire width direction. The form of the lug groove 30 such as a curve or an inclination in the tire circumferential direction with respect to the tire width direction is appropriately set according to a target tread pattern.

  The block 10 is partitioned by the circumferential main groove 20 and the lug groove 30. As the block 10, the center block 11 that is the first land portion located between the two center main grooves 21 and the adjacent center main A second block 12 that is a second land portion located between the groove 21 and the second main groove 22 and a shoulder block 13 that is a third land portion located on the outer side in the tire width direction of the second main groove 22 are provided. ing. Among these, the center block 11 is located on the tire equator line CL and is partitioned by the center main groove 21 and the center lug groove 31. The second block 12 is formed adjacent to the center block 11 via the center main groove 21, and is partitioned by the center main groove 21, the second main groove 22, and the first second lug groove 32. That is, the second block 12 is defined by the center main groove 21 and the second main groove 22 on both sides in the tire width direction, and is defined by the two first second lug grooves 32 on both sides in the tire circumferential direction. The second second lug groove 33 terminates in the second block 12 at the inner end in the tire width direction.

  Further, the shoulder block 13 is formed adjacent to the second block 12 via the second main groove 22, and is partitioned by the second main groove 22 and the shoulder lug groove 34. The shoulder block 13 is formed with a shoulder narrow groove 50 that extends in the tire circumferential direction and has one end connected to the shoulder lug groove 34 and the other end terminating in the shoulder block 13. As described above, the center block 11, the second block 12, and the shoulder block 13 are each formed in a block shape by being partitioned by the circumferential main groove 20 and the lug groove 30.

  A large number of sipes 55 are formed on the tread surface 3. The sipe 55 is formed in each block 10 of the center block 11, the second block 12, and the shoulder block 13, and has a zigzag shape that extends in the tire width direction and swings in the tire circumferential direction.

  Here, the sipe 55 is formed in a narrow groove shape on the tread surface 3, and the pneumatic tire 1 is assembled on a regular rim to form a narrow groove when no load is applied under the normal internal pressure condition. When the narrow groove is located in the part of the ground contact surface formed on the flat plate when loaded in the vertical direction on the flat plate, or when the land part where the narrow groove is formed falls, The wall surface which comprises the said fine groove, or at least one part of the site | part provided in a wall surface says what mutually contacts by deformation | transformation of a land part. The regular rim is “standard rim” defined by JATMA, “Design Rim” defined by TRA, or “Measuring Rim” defined by ETRTO. The normal internal pressure is “maximum air pressure” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO. In the present embodiment, the sipe 55 has a width in the range of 0.6 mm to 1.0 mm, and a depth in the range of 6.0 mm to 8.0 mm.

  FIG. 2 is a detailed view of part A of FIG. Of the blocks 10 formed on the tread surface 3, the second block 12 includes a pair of peripheral grooves between the two first second lug grooves 32 and the second second lug grooves 33 that define the second block 12. Directionally inclined narrow grooves 40 are provided. The pair of circumferentially inclined narrow grooves 40 extends in a direction inclined in the tire width direction with respect to the tire circumferential direction, and both ends are connected to the first second lug groove 32 and the second second lug groove 33. Further, the pair of circumferentially inclined narrow grooves 40 are connected to the second second lug groove 33 at different positions connected to the second second lug groove 33 in the tire width direction.

  Specifically, one second block 12 is provided with a first circumferentially inclined narrow groove 41 and a second circumferentially inclined narrow groove 42 as a pair of circumferentially inclined narrow grooves 40. Among these, the first circumferentially inclined narrow groove 41 has one end connected to the first second lug groove 32 and the other end connected to the second second lug groove 33. The first circumferentially inclined narrow groove 41 extends in the tire circumferential direction from the end side connected to the first second lug groove 32 toward the end side connected to the second second lug groove 33. However, it is inclined in a direction toward the outer side in the tire width direction. For this reason, the 1st circumferential direction inclination narrow groove 41 is a tire width direction by the edge part by the side connected to the 1st second drag groove 32, and the edge part by the side connected to the 2nd second drag groove 33. The position in is different.

  Further, the second circumferentially inclined narrow groove 42 has one end from the opposite side of the second second lug groove 33 to the side where the first circumferentially inclined narrow groove 41 is connected in the tire circumferential direction. 33, and the other end is connected to a first second lug groove 32 different from the first second lug groove 32 on the side to which the first circumferentially inclined narrow groove 41 is connected. The second circumferentially inclined narrow groove 42 extends in the tire circumferential direction from the end side connected to the second second lug groove 33 toward the end side connected to the first second lug groove 32. However, it is inclined in a direction toward the outer side in the tire width direction. Therefore, the second circumferentially inclined narrow groove 42 is connected to the end connected to the first second drag groove 32 and the second second drag groove 33 in the same manner as the first circumferentially inclined narrow groove 41. The position in the tire width direction is different from the end portion on the side where the tire is located.

  The first circumferential inclined narrow groove 41 and the second circumferential inclined narrow groove 42 include an end portion of the first circumferential inclined narrow groove 41 on the side connected to the first second lug groove 32, and a second circumferential The position in the tire width direction is close to the end portion of the direction inclined narrow groove 42 on the side connected to the second second lug groove 33. Moreover, the edge part by the side connected to the 2nd second drag groove 33 in the 1st circumferential direction inclination fine groove 41, and the edge part by the side connected to the 1st second drag groove 32 in the 2nd circumferential direction inclination narrow groove 42 Thus, the positions in the tire width direction are close to each other.

  For this reason, the end portions of the first circumferential inclined narrow groove 41 and the second circumferential inclined narrow groove 42 on the side connected to the second second drag groove 33 are the end portions of the second circumferential inclined narrow groove 42. The position in the tire width direction of the end portion of the first circumferential inclined groove 41 is located on the outer side in the tire width direction than the position in the tire width direction. Further, the first circumferentially inclined narrow grooves 41 and the second circumferentially inclined narrow grooves 42 that are alternately arranged in the tire circumferential direction are spaced apart from each other by a plurality of first circumferentially inclined narrow grooves 41 in the tire circumferential direction. The first circumferential direction inclined narrow groove 41 and the second circumferential direction inclined narrow groove 42 are arranged in the tire width direction with respect to the tire circumferential direction because the second circumferential direction inclined narrow grooves 42 are spaced at equal intervals. The inclination angles are all the same. That is, the first circumferentially inclined narrow groove 41 and the second circumferentially inclined narrow groove 42 are formed substantially in parallel.

  In addition, the second block 12 has a circumferentially inclined narrow groove 40 connected to the first second lug groove 32 and the second second lug groove 33 extending beyond the first second lug groove 32 and the second second lug groove 33. A circumferentially inclined narrow groove extension 45 is formed at the position. The circumferentially inclined narrow groove extension 45 is located on the side opposite to the side where the first circumferentially inclined narrow groove 41 is connected in the groove width direction of the second second lug groove 33. Is formed at an extended position. Similarly, the circumferentially inclined narrow groove extension 45 is inclined in the second circumferential direction at a position on the opposite side to the side where the second circumferentially inclined narrow groove 42 is connected in the groove width direction of the second second lug groove 33. The narrow groove 42 is formed at an extended position.

  Further, the circumferentially inclined narrow groove extending portion 45 is also formed at a position where the circumferentially inclined narrow groove 40 formed in the second block 12 adjacent in the tire circumferential direction is extended via the first second lug groove 32. . That is, the circumferentially inclined narrow groove extension 45 is opposite to the side where the first circumferentially inclined narrow groove 41 formed in the adjacent second block 12 is connected in the groove width direction of the first second lug groove 32. In this position, the first circumferentially inclined narrow groove 41 is formed at an extended position. Similarly, the circumferentially inclined narrow groove extension 45 is opposite to the side where the second circumferentially inclined narrow groove 42 formed in the adjacent second block 12 is connected in the groove width direction of the first second lug groove 32. It is formed in the position which extended the 2nd circumferential direction inclination fine groove 42 in the position of the side. These circumferentially inclined narrow groove extending portions 45 are formed so that the length in the longitudinal direction of the circumferentially inclined narrow groove 40 is a predetermined short length. For example, the first circumferentially inclined narrow groove 41 extends. The length in the direction or the length in the direction in which the second circumferentially inclined narrow groove 42 extends is slightly longer than the groove width of the first circumferentially inclined narrow groove 41 or the second circumferentially inclined narrow groove 42. It has become.

  In the second block 12, a center lug groove extending portion 35 is formed at a position where the center lug groove 31 connected to the center main groove 21 is extended outward in the tire width direction beyond the center main groove 21. . The center lug groove extending portion 35 is formed at a position on the opposite side of the center main groove 21 to the side where the center lug groove 31 is connected in the groove width direction and extending the center lug groove 31. The center lug groove extension 35 is also formed with a predetermined short length in the length direction of the center lug groove 31.

  FIG. 3 is a detailed view of part B of FIG. The plurality of circumferentially inclined narrow grooves 40 formed substantially in parallel have an inclination angle α in the tire width direction with respect to the tire circumferential direction within a range of 10 ° ≦ α ≦ 70 °. In this case, the inclination angle α is the circumferential inclination between the end connected to the first second lug groove 32 and the end connected to the second second lug groove 33 in the circumferential inclined narrow groove 40. The straight line connecting the centers of the narrow grooves 40 in the groove width direction is an angle with respect to the tire circumferential direction. The inclination angle α of the circumferential inclined narrow groove 40 with respect to the tire circumferential direction is preferably in the range of 20 ° ≦ α ≦ 45 °. Further, in the first circumferential direction inclined narrow groove 41 and the second circumferential direction inclined narrow groove 42, it is preferable that the inclination angle α in the tire width direction with respect to the tire circumferential direction is the same angle or close angle. The inclination angle α of the circumferential inclined narrow groove 41 and the second circumferential inclined narrow groove 42 may not be the same angle. Moreover, the inclination angle α may be the same between the circumferential inclined narrow grooves 40 of different second blocks 12, and the inclination angle α of the circumferential inclined narrow grooves 40 may be different depending on the second block 12.

  Further, the circumferentially inclined narrow groove 40 has two or more groove width change points 46 that are one change point of the groove width. That is, each circumferentially inclined narrow groove 40 has a portion where the groove width changes abruptly when at least one of the groove walls 43 located on both sides in the groove width direction is bent in the groove width direction. Thus, the portion where the groove width changes abruptly becomes a groove width changing point 46. The circumferentially inclined narrow groove 40 has a groove width change amount Wg at a groove width change point 46 in a range of 0.5 mm ≦ Wg ≦ 5.0 mm. The change amount Wg of the groove width in this case is the difference between the groove widths at positions on both sides of the groove width change point 46 in the extending direction of the circumferentially inclined narrow groove 40. The circumferentially inclined narrow groove 40 has two or more groove width changing points 46 at which the groove width changes abruptly in both the first circumferentially inclined narrow groove 41 and the second circumferentially inclined narrow groove 42. Yes.

  The change amount Wg of the groove width at the groove width change point 46 is preferably in the range of 1.0 mm ≦ Wg ≦ 4.0 mm. Further, the number of groove width change points 46 and the change amount Wg of the groove width may be the same number and change amount Wg in all the circumferential inclined narrow grooves 40, and are different for each circumferential inclined narrow groove 40. Also good. Further, the groove width is changed at the groove width change point 46 when the groove width change point 46 is wide or narrow when viewed in one direction in the length direction of the circumferential inclined narrow groove 40. The direction in which the groove width changes may be different for each groove width changing point 46. Further, at the groove width changing point 46, even if the groove width is changed by bending one groove wall 43 in the groove width direction among the groove walls 43 on both sides in the groove width direction of the circumferential inclined narrow groove 40. The groove width may be changed by bending both the groove walls 43. At the groove width change point 46, it is only necessary that the groove width changes abruptly, and it does not depend on the direction in which the groove width changes or the way the groove width changes.

  FIG. 4 is a cross-sectional view taken along line EE in FIG. Further, the circumferentially inclined narrow groove 40 has two or more groove depth change points 47 that are the change points of the groove depth. That is, each circumferentially inclined narrow groove 40 has a portion where the groove depth changes abruptly when the groove bottom 44 is bent in the groove depth direction. Thus, the portion where the groove depth changes abruptly is the groove depth changing point 47. The circumferentially inclined narrow groove 40 has a groove depth change amount Dg at a groove depth change point 47 in a range of 2.0 mm ≦ Dg ≦ 6.0 mm. The groove depth change amount Dg in this case is the difference between the groove depths at positions on both sides of the groove depth changing point 47 in the extending direction of the circumferentially inclined narrow groove 40. The circumferentially inclined narrow groove 40 has two or more groove depth change points 47 at which the groove depth changes abruptly in both the first circumferentially inclined narrow groove 41 and the second circumferentially inclined narrow groove 42. doing.

  The groove depth change amount Dg at the groove depth changing point 47 is preferably in the range of 3.0 mm ≦ Dg ≦ 5.0 mm. Further, the number of groove depth change points 47 and the change amount Dg of the groove depth may be the same number and change amount Dg in all the circumferential inclined narrow grooves 40, and are different for each circumferential inclined narrow groove 40. It may be. Further, the groove depth is changed at the groove depth changing point 47 when the groove depth is changed at each groove depth changing point 47 when viewed in one direction in the length direction of the circumferentially inclined narrow groove 40. It may be deeper or shallower, and the direction in which the groove depth changes may be different for each groove depth changing point 47. At the groove depth changing point 47, it is only necessary that the groove depth changes abruptly, and the groove depth changing point 47 does not depend on the direction in which the groove depth changes.

  FIG. 5 is a detailed view of part C of FIG. FIG. 6 is a detailed view of a portion D in FIG. Further, the center main groove 21 and the second main groove 22 respectively have a long portion 24 and a short portion 25 having different relative lengths at least on the groove wall 23 adjacent to the second block 12. The long portion 24 and the short portion 25 have a relative length that is longer in the long portion 24 than in the short portion 25, and in both the center main groove 21 and the second main groove 22, the tire circumference They are arranged alternately in the direction. Further, the long portion 24 and the short portion 25 are formed such that the inclination directions in the tire width direction with respect to the tire circumferential direction are opposite to each other.

  Specifically, the center main groove 21 is a zigzag-shaped groove that swings in the tire width direction while extending in the tire circumferential direction with a constant groove width. For this reason, it has the long part 24 and the short part 25 in both the groove walls 23 located in the both sides of a groove width direction. On the other hand, the second main groove 22 has an amplitude in the tire width direction while the groove wall 23 adjacent to the second block 12 extends in the tire circumferential direction, whereas the groove wall 23 on the shoulder block 13 side has an amplitude in the tire width direction. Without extending, it extends along the tire circumferential direction. For this reason, the second main groove 22 has a long portion 24 and a short portion 25 only in the groove wall 23 adjacent to the second block 12.

  As described above, the center main groove 21 and the second main groove 22 having the long portion 24 and the short portion 25 are arranged so that the inclination direction of the long portion 24 in the tire width direction with respect to the tire circumferential direction is the circumferential inclined narrow groove 40. It is the direction opposite to the inclination direction to the tire width direction with respect to the tire circumferential direction. That is, when the circumferentially inclined narrow groove 40 is inclined in the direction toward the outer side in the tire width direction toward the predetermined direction in the tire circumferential direction, the groove wall 23 of the center main groove 21 and the second main groove 22 is formed. The long portion 24 is inclined in the direction toward the inner side in the tire width direction as it goes in the same direction in the tire circumferential direction.

  In addition, as for the short part 25 of the groove wall 23 of the center main groove 21 and the second main groove 22, the inclination direction to the tire width direction with respect to the tire circumferential direction is the tire width direction with respect to the tire circumferential direction of the circumferential inclined narrow groove 40. The direction is the same as the tilt direction.

  The groove wall 23 of the center main groove 21 and the second main groove 22 in which the inclination direction in the tire width direction with respect to the tire circumferential direction is opposite to the inclination direction in the tire width direction with respect to the tire circumferential direction of the circumferential inclined groove 40. The long portion 24 has an inclination angle β with respect to the tire circumferential direction in a range of 5 ° ≦ β ≦ 40 °. That is, the long part 24 of the groove wall 23 adjacent to the second block 12 in the center main groove 21 has an inclination angle β with respect to the tire circumferential direction in a range of 5 ° ≦ β ≦ 40 °. Similarly, the long portion 24 of the groove wall 23 adjacent to the second block 12 in the second main groove 22 also has an inclination angle β with respect to the tire circumferential direction in a range of 5 ° ≦ β ≦ 40 °.

  The inclination angle β of the elongated portion 24 of the groove wall 23 of the center main groove 21 and the groove wall 23 of the second main groove 22 with respect to the tire circumferential direction is preferably within a range of 10 ° ≦ β ≦ 30 °, respectively. Preferably there is. In addition, the center main groove 21 and the second main groove 22 may have the same or different inclination angles β of the long portions 24 of the groove walls 23. Regardless of the relative relationship between the inclination angles β of the long portions 24 of the center main groove 21 and the second main groove 22, the inclination angles β of any of the long portions 24 are within the range of 5 ° ≦ β ≦ 40 °. And preferably within the range of 10 ° ≦ β ≦ 30 °.

  FIG. 7 is a detailed view of the first second lug groove shown in FIG. FIG. 8 is a detailed view of the second second lug groove shown in FIG. The first second lug groove 32 and the second second lug groove 33 have a groove width changing point, like the circumferentially inclined narrow groove 40. That is, the first second lug groove 32 has at least one groove width changing point 36 that is a changing point of the groove width, and the second second lug groove 33 is a groove width changing point that is the changing point of the groove width. 37 or more. In this case, the groove width changing point 36 of the first second lug groove 32 and the groove width changing point 37 of the second second lug groove 33 are the same as the groove width changing point 46 of the circumferentially inclined narrow groove 40, as in the first second lug groove 46. At least one of the groove walls on both sides of the groove 32 and the second second lug groove 33 in the groove width direction is bent in the groove width direction, so that the groove width changes abruptly. The first second lug groove 32 has a change amount W1 at the groove width change point 36 in the range of 1.0 mm ≦ W1 ≦ 3.0 mm. The second second lug groove 33 has a change amount W2 at the groove width changing point 37 in a range of 0.5 mm ≦ W2 ≦ 2.5 mm.

  It should be noted that the number of groove width change points 36 of the first second lug grooves 32 and the change amount W1 of the groove width may be the same number and change amount W1 in all the first second lug grooves 32. Each groove 32 may be different. Similarly, the number of groove width change points 37 of the second second lug grooves 33 and the change amount W2 of the groove width may be the same number and change amount W2 in all the second second lug grooves 33. It may be different for each lug groove 33.

  When the pneumatic tire 1 configured as described above is mounted on a vehicle and travels, the pneumatic tire 1 rotates while the tread surface 3 positioned below the tread surface 3 is in contact with the road surface. When driving on a dry road surface with a vehicle equipped with pneumatic tires 1, the driving force or braking force is transmitted to the road surface or the turning force is generated mainly by the frictional force between the tread surface 3 and the road surface. To drive. Further, when traveling on a wet road surface, water between the tread surface 3 and the road surface enters the circumferential main groove 20, the lug groove 30, and the like, and water between the tread surface 3 and the road surface in these grooves. Drive while draining. As a result, the tread surface 3 is easily grounded to the road surface, and the vehicle can travel by the frictional force between the tread surface 3 and the road surface.

  Further, when traveling on a snowy road surface, the pneumatic tire 1 compresses the snow on the road surface with the tread surface 3, and the snow on the road surface enters the circumferential main grooves 20 and the lug grooves 30. Will be pressed into the groove. In this state, a driving force or a braking force is applied to the pneumatic tire 1 or a force in the tire width direction is applied by turning of the vehicle, whereby the shearing force is applied to the snow in the groove. A so-called snow shear force is generated between the pneumatic tire 1 and snow. When traveling on a snowy road surface, resistance is generated between the pneumatic tire 1 and the road surface by the shear force in the snow, so that driving force and braking force can be transmitted to the road surface. It becomes possible to run on.

  Further, when traveling on a snowy road surface or an icy road surface, the vehicle travels using the edge effect of the circumferential main groove 20, the lug groove 30 and the sipe 55. That is, when traveling on a snowy road surface or an iced road surface, the vehicle travels using resistance caused by the edge of the circumferential main groove 20 or the edge of the sipe 55 being caught on the snow surface or ice surface. Further, when traveling on an icy road surface, water on the surface of the icy road surface is absorbed by the sipe 55, and the water film between the icy road surface and the tread surface 3 is removed so that the icy road surface and the tread surface 3 are in contact with each other. It becomes easy to do. As a result, the tread surface 3 is increased in resistance between the road surface on ice due to frictional force and edge effect, and the traveling performance of the vehicle equipped with the pneumatic tire 1 can be ensured. When running on snowy or icy roads, the edge effect can be used to secure the running performance. However, if the groove on the tread surface 3 is increased to secure the edge effect, Since the rigidity is lowered, it is difficult to ensure steering stability.

  On the other hand, in the pneumatic tire 1 according to the present embodiment, the second second lug groove 33 is provided between the two first second lug grooves 32 that define both sides of the second block 12 in the tire circumferential direction. A pair of circumferentially inclined narrow grooves 40 are formed between the two first second lug grooves 32 and the second second lug grooves 33. Since the pair of circumferentially inclined narrow grooves 40 is inclined in the tire width direction with respect to the tire circumferential direction, the circumferentially inclined narrow grooves 40 ensure edge components in both the tire circumferential direction and the tire width direction. be able to. Further, a long portion 24 and a short portion 25 are formed in the center main groove 21 and the second main groove 22 respectively, and the inclination direction of the long portion 24 in the tire width direction with respect to the tire circumferential direction is changed to the circumferentially inclined narrow groove. Since the direction is opposite to the inclination direction of 40, the edge component can be secured in all directions without the edge component being biased in a specific direction.

  Of these, the edge component that can be secured by the elongated portion 24 of the center main groove 21 and the second main groove 22 is not a newly added groove to secure the edge component, so the edge component does not decrease the block rigidity. Ingredients can be secured. Further, since the edge component that can be secured by the circumferentially inclined narrow groove 40 is secured by inclining a groove having a narrow groove width with respect to the tire circumferential direction, the edge component is secured without significantly reducing the block rigidity. be able to.

  In the pneumatic tire 1 according to the present embodiment, the circumferentially inclined narrow groove 40 is formed in the second block 12 as described above, and the inclined direction of the long portion 24 of the center main groove 21 and the second main groove 22 is further rotated. By tilting in the direction opposite to the tilt direction of the direction tilting narrow groove 40, it is possible to secure an edge component in all directions while securing a block stiffness while minimizing a decrease in the block stiffness of the second block 12. As a result, the braking stability and driving performance on the ice can be ensured by the edge component in all directions, and the steering stability such as the turning performance on the ice can be secured by the block rigidity. As a result, the performance on ice can be improved. be able to.

  Moreover, since the inclination angle α with respect to the circumferential direction of the tire is within a range of 10 ° ≦ α ≦ 70 °, the circumferentially inclined narrow groove 40 appropriately has an edge component in either the tire circumferential direction or the tire width direction. Can be secured. That is, when the inclination angle α of the circumferential inclined groove 40 is less than 10 °, the inclination angle α of the circumferential inclined groove 40 in the tire width direction is too small. It becomes difficult to improve the edge component in the front-rear direction. In this case, it may be difficult to ensure braking performance on ice. Further, when the inclination angle α of the circumferential inclined groove 40 is larger than 70 °, the inclination angle α of the circumferential inclined groove 40 in the tire width direction is too large, so that it is difficult to improve the edge component in the tire width direction. Become. In this case, it may be difficult to ensure turning performance on ice. On the other hand, when the inclination angle α of the circumferentially inclined narrow groove 40 is in the range of 10 ° ≦ α ≦ 70 °, the edge components in both the tire circumferential direction and the tire width direction are appropriately ensured. Therefore, both the braking performance and the turning performance on ice can be ensured more reliably. As a result, the on-ice performance can be improved more reliably.

  Further, since the long portion 24 of the groove wall 23 of the center main groove 21 and the second main groove 22 has an inclination angle β with respect to the tire circumferential direction within a range of 5 ° ≦ β ≦ 40 °, the tire circumferential direction and the tire Edge components in either direction of the width direction can be appropriately secured. That is, when the inclination angle β of the long portion 24 of the center main groove 21 or the second main groove 22 is less than 5 °, the inclination angle β of the long portion 24 of the center main groove 21 or the second main groove 22 is too small. For this reason, it is difficult to improve the edge component in the front-rear direction when the vehicle is traveling, and it may be difficult to ensure braking performance on ice. Further, when the inclination angle β of the long portion 24 of the center main groove 21 or the second main groove 22 exceeds 40 °, the inclination angle β of the long portion 24 of the center main groove 21 or the second main groove 22 is too large. It may be difficult to improve the edge component in the tire width direction, and it may be difficult to ensure turning performance on ice. On the other hand, when the inclination angle β of the long portion 24 of the center main groove 21 or the second main groove 22 is in the range of 5 ° ≦ β ≦ 40 °, any direction of the tire circumferential direction and the tire width direction The edge component can be appropriately ensured, and both the braking performance and turning performance on ice can be ensured more reliably. As a result, the on-ice performance can be improved more reliably.

  Further, since the circumferentially inclined narrow groove 40 has two or more groove depth change points 47 in one circumferentially inclined narrow groove 40, the circumferentially inclined narrow groove 40 has a plurality of groove depths when the second block 12 is grounded. It becomes easy to kink at the change point 47, and the tread surface 3 of the second block 12 is easily grounded. As a result, the edge of the circumferentially inclined narrow groove 40 is also easily grounded, and the edge effect can be improved more reliably. As a result, the turning performance on ice and the braking performance on ice can be improved more reliably, and the performance on ice can be improved more reliably.

  Further, since the amount of change Dg at the groove depth changing point 47 is in the range of 2.0 mm ≦ Dg ≦ 6.0 mm, the circumferentially inclined narrow groove 40 has an edge effect while suppressing the occurrence of cracks. Can be improved. That is, when the change amount Dg at the groove depth change point 47 of the circumferentially inclined narrow groove 40 is less than 2.0 mm, the change amount Dg at the groove depth change point 47 is too small, so There is a possibility that the groove 40 is not easily kinked at the groove depth changing point 47. In this case, since the second block 12 is not easily twisted, the edge of the circumferentially inclined narrow groove 40 is difficult to be grounded when the second block 12 is grounded, and the edge effect may not be effectively improved. Further, when the change amount Dg at the groove depth change point 47 of the circumferentially inclined narrow groove 40 is larger than 6.0 mm, the change amount Dg at the groove depth change point 47 is too large. 40 is likely to be kinked more than necessary around the groove depth changing point 47, and the circumferentially inclined narrow groove 40 may be kinked greatly when the second block 12 is grounded, so that cracks are likely to occur. On the other hand, when the amount of change Dg at the groove depth change point 47 of the circumferentially inclined narrow groove 40 is within the range of 2.0 mm ≦ Dg ≦ 6.0 mm, the circumferentially inclined narrow groove 40 is largely twisted. The edge effect can be more reliably improved while suppressing the occurrence of cracks due to the above. As a result, the performance on ice can be improved more reliably while suppressing the occurrence of cracks.

  Further, since the circumferential inclined narrow groove 40 has two or more groove width changing points 46 in one circumferential inclined narrow groove 40, the circumferential inclined narrow groove 40 has a plurality of groove width changing points when the second block 12 is grounded. 46, the tread surface 3 of the second block 12 is easily grounded. As a result, the edge of the circumferentially inclined narrow groove 40 is also easily grounded, and the edge effect can be improved more reliably. As a result, the turning performance on ice and the braking performance on ice can be improved more reliably, and the performance on ice can be improved more reliably.

  In addition, since the amount of change Wg at the groove width change point 46 is in the range of 0.5 mm ≦ Wg ≦ 5.0 mm, the circumferentially inclined narrow groove 40 improves the edge effect while suppressing the occurrence of cracks. Can be made. That is, when the change amount Wg at the groove width change point 46 of the circumferentially inclined narrow groove 40 is less than 0.5 mm, the change amount Wg at the groove width change point 46 is too small, and thus the circumferentially inclined narrow groove 40. May become difficult to kink at the groove width change point 46. In this case, since the second block 12 is not easily twisted, the edge of the circumferentially inclined narrow groove 40 is difficult to be grounded when the second block 12 is grounded, and the edge effect may not be effectively improved. Further, when the change amount Wg at the groove width change point 46 of the circumferentially inclined narrow groove 40 is larger than 5.0 mm, the change amount Wg at the groove width change point 46 is too large. There is a possibility that cracks are likely to occur due to kinking more easily than necessary around the groove width changing point 46, and the circumferentially inclined narrow grooves 40 being largely kinked when the second block 12 is grounded. On the other hand, when the amount of change Wg at the groove width change point 46 of the circumferentially inclined narrow groove 40 is within the range of 0.5 mm ≦ Wg ≦ 5.0 mm, the circumferentially inclined narrow groove 40 is greatly kinked. The edge effect can be more reliably improved while suppressing the occurrence of cracks due to the above. As a result, the performance on ice can be improved more reliably while suppressing the occurrence of cracks.

  Further, since the first second lug groove 32 has one or more groove width changing points 36, the first second lug groove 32 is easily kinked at the groove width changing point 36 when the second block 12 is grounded, and the tread of the second block 12 is treaded. Surface 3 is easy to ground. Accordingly, the edge of the first second lug groove 32 is also easily grounded, so that the edge effect can be improved more reliably. As a result, the turning performance on ice and the braking performance on ice can be improved more reliably, and the performance on ice can be improved more reliably.

  The first second lug groove 32 has a change amount W1 at the groove width changing point 36 in the range of 1.0 mm ≦ W1 ≦ 3.0 mm, so that the edge effect is improved while suppressing the occurrence of cracks. Can be made. That is, when the change amount W1 at the groove width change point 36 of the first second lug groove 32 is less than 1.0 mm, the change amount W1 at the groove width change point 36 is too small, and thus the first second drag groove 32. May become difficult to kink at the groove width change point 36. In this case, since the second block 12 is not easily twisted, the edge of the first second lug groove 32 is difficult to ground when the second block 12 is grounded, and the edge effect may not be effectively improved. When the change amount W1 at the groove width change point 36 of the first second lug groove 32 is larger than 3.0 mm, the change amount W1 at the groove width change point 36 is too large. There is a possibility that cracks are likely to occur due to kinking more easily than necessary around the groove width change point 36 and the first second lug groove 32 being largely kinked when the second block 12 is grounded. On the other hand, when the amount of change W1 at the groove width change point 36 of the first second drag groove 32 is in the range of 1.0 mm ≦ W1 ≦ 3.0 mm, the first second drag groove 32 is greatly twisted. The edge effect can be more reliably improved while suppressing the occurrence of cracks due to the above. As a result, the performance on ice can be improved more reliably while suppressing the occurrence of cracks.

  Further, since the second second lug groove 33 has one or more groove width changing points 37, the second second lug groove 33 is easily kinked at the groove width changing point 37 when the second block 12 is grounded, and the tread of the second block 12. Surface 3 is easy to ground. As a result, the edge of the second second lug groove 33 is also easily grounded, so that the edge effect can be improved more reliably. As a result, the turning performance on ice and the braking performance on ice can be improved more reliably, and the performance on ice can be improved more reliably.

  In addition, since the amount of change W2 at the groove width change point 37 is in the range of 0.5 mm ≦ W2 ≦ 2.5 mm, the second second lug groove 33 improves the edge effect while suppressing the occurrence of cracks. Can be made. That is, when the change amount W2 at the groove width change point 37 of the second second drag groove 33 is less than 0.5 mm, the change amount W2 at the groove width change point 37 is too small. May become difficult to kink at the groove width change point 37. In this case, since the second block 12 is not easily twisted, the edge of the second second lug groove 33 is difficult to be grounded when the second block 12 is grounded, and the edge effect may not be effectively improved. When the change amount W2 at the groove width change point 37 of the second second lug groove 33 is larger than 2.5 mm, the change amount W2 at the groove width change point 37 is too large. There is a possibility that cracks are likely to occur because the second second lug grooves 33 are kinked more easily than necessary when the second block 12 is grounded. On the other hand, when the amount of change W2 at the groove width changing point 37 of the second second drag groove 33 is within the range of 0.5 mm ≦ W2 ≦ 2.5 mm, the second second drag groove 33 is greatly twisted. The edge effect can be more reliably improved while suppressing the occurrence of cracks due to the above. As a result, the performance on ice can be improved more reliably while suppressing the occurrence of cracks.

  In addition, since the center lug groove extending portion 35 and the circumferentially inclined narrow groove extending portion 45 are formed in the second block 12, a region having a large surface with few edges is formed in the second block 12. Can be suppressed. Thereby, it can suppress that the difference in block rigidity generate | occur | produces in one second block 12. FIG. That is, in the area where the grooves such as the second second lug groove 33 and the circumferentially inclined narrow groove 40 are dense, the block rigidity is likely to be lower than in the area where these grooves are not dense, but the groove By providing the center lug groove extension 35 and the circumferentially inclined narrow groove extension 45 in a non-dense area, the block rigidity of this area can be reduced. Thereby, the block rigidity of the entire second block 12 can be made uniform. As a result, uneven wear due to the occurrence of a block rigidity difference in one block 10 can be suppressed.

  In the pneumatic tire 1 according to the above-described embodiment, the pair of circumferentially inclined narrow grooves 40 are provided on both sides of the tire equator line CL in the tire width direction, and are opposite to the inclined direction of the circumferentially inclined narrow grooves 40. Although the long portion 24 inclined in the direction is also formed in the center main groove 21 and the second main groove 22 on both sides of the tire equator line CL, the circumferentially inclined narrow groove 40 and the long portion 24 are formed in the tire width direction. Either one is acceptable. That is, the long portion 24 and the circumferentially inclined narrow groove 40 of the circumferential main groove 20 may be provided only on the inner side of the tire equator line CL in the vehicle mounting direction when the pneumatic tire 1 is mounted on the vehicle. The tire equator line CL may be provided only on the outer side in the vehicle mounting direction.

  In the pneumatic tire 1 according to the above-described embodiment, four circumferential main grooves 20 are formed, and the circumferential inclined narrow grooves 40 are formed in the second block 12. The formed block 10 may be other than the second block 12. Regardless of the block 10 in which the circumferentially inclined narrow groove 40 is formed, the circumferentially inclined narrow groove 40 that is inclined with respect to the tire circumferential direction is formed in the block 10, and the circumferential main groove 20 that partitions the block 10 is By providing the long portion 24 that inclines in the direction opposite to the inclination direction of the direction inclined narrow groove 40, it is possible to ensure edge components in all directions while ensuring block rigidity.

〔Example〕
9A to 9C are tables showing results of performance tests of pneumatic tires. Hereinafter, the performance evaluation test performed on the pneumatic tire 1 of the conventional example and the pneumatic tire 1 according to the present invention will be described. In the performance evaluation test, tests on ice braking showing braking performance on ice and turning on ice showing steering stability on ice were conducted.

  In the performance evaluation test, a pneumatic tire 1 with a tire size specified by JATMA of 195 / 65R15 91Q size was assembled to a rim wheel of a 15 × 6.0J size JATMA standard rim, and the air pressure was adjusted to 210 kPa. The test was carried out by mounting the test vehicle. As for the evaluation method of each test item, the braking on ice was evaluated by performing a braking test by a test driver on a test course on an ice surface, and expressing the reciprocal of the braking distance by an index with a conventional example as 100 described later. The larger the value, the shorter the braking distance and the better the braking on ice. Further, the swirlability on ice was evaluated by performing a sensory evaluation by a test driver when traveling on a test course on an ice surface with a test vehicle, and expressing the sensory evaluation as an index with the conventional example described later as 100. The larger the value, the better the swirlability on ice.

  The evaluation test was conducted on a conventional pneumatic tire which is an example of a conventional pneumatic tire 1 and Examples 1 to 16 which are the pneumatic tire 1 according to the present invention. Among these pneumatic tires 1, in the conventional pneumatic tire, the circumferentially inclined narrow groove 40 is not formed in the second block 12, and the groove wall 23 of the circumferential main groove 20 is in the tire circumferential direction. It does not have an inclined part.

  In contrast, in Examples 1 to 16, which are examples of the pneumatic tire 1 according to the present invention, a pair of circumferentially inclined narrow grooves 40 are formed in the second block 12, and the groove wall of the circumferential main groove 20 is formed. 23 has a portion inclined with respect to the tire circumferential direction. In addition, the pneumatic tire 1 according to Examples 1 to 16 includes the inclination angle of the circumferentially inclined narrow groove 40, the inclination angle of the long portion 24 included in the circumferential main groove 20, and the groove depth of the circumferentially inclined narrow groove 40. The number of height change points 47 and the change amount of the groove depth, the number of groove width change points 46 and the change amount of the groove width of the circumferentially inclined narrow groove 40, the presence or absence of the groove width change point 36 of the first second drag groove 32, The presence or absence of a groove width changing point 37 of the second second lug groove 33 is different.

  As a result of performing an evaluation test using these pneumatic tires 1, as shown in FIGS. 9A to 9C, the pneumatic tires 1 of Examples 1 to 16 are braked on ice and turned on ice as compared with the conventional example. It was found that both can be improved. That is, the pneumatic tire 1 according to Examples 1 to 16 can improve the performance on ice.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 3 Tread surface 10 Block 11 Center block 12 Second block 20 Circumferential main groove 21 Center main groove (first main groove)
22 Second main groove (second main groove)
23, 43 Groove wall 24 Long part 25 Short part 30 Lug groove 31 Center lug groove 32 First second lug groove (first lug groove)
33 Second second lug groove (second lug groove)
36, 37, 46 Groove width changing point 40 Circumferentially inclined narrow groove 41 First circumferentially inclined narrow groove 42 Second circumferentially inclined narrow groove 47 Groove depth changing point

Claims (11)

A first main groove extending in the tire circumferential direction;
A second main groove extending in the tire circumferential direction and adjacent to the first main groove;
A first lug groove extending in the tire width direction and having both ends connected to the first main groove and the second main groove;
Blocks in which both sides in the tire width direction are partitioned by the first main groove and the second main groove, and both sides in the tire circumferential direction are partitioned by the two first lug grooves;
A second lug groove extending in the tire width direction and having one end connected to the second main groove and the other end terminating in the block;
Two first lug grooves that extend in a direction inclined in the tire width direction with respect to the tire circumferential direction, are connected at both ends to the first lug groove and the second lug groove, and define the block A pair of circumferentially inclined narrow grooves disposed between each of the second lug grooves;
With
The pair of circumferentially inclined narrow grooves are different from each other in positions connected to the second lug grooves in the tire width direction.
The first main groove and the second main groove are formed on the groove wall adjacent to the block so that the inclination directions in the tire width direction with respect to the tire circumferential direction are opposite to each other, and the relative lengths are different. And having a long part and a short part arranged alternately in the tire circumferential direction,
In the first main groove and the second main groove, the inclination direction of the long portion in the tire width direction with respect to the tire circumferential direction is in the inclination direction in the tire width direction with respect to the tire circumferential direction of the circumferential inclination narrow groove. A pneumatic tire characterized by being in the opposite direction.   2. The pneumatic tire according to claim 1, wherein the circumferential inclined narrow groove has an inclination angle α with respect to the tire circumferential direction within a range of 10 ° ≦ α ≦ 70 °.   3. The pneumatic tire according to claim 1, wherein the elongated portion of the first main groove and the second main groove has an inclination angle β with respect to a tire circumferential direction within a range of 5 ° ≦ β ≦ 40 °.   The pneumatic tire according to any one of claims 1 to 3, wherein the circumferentially inclined narrow groove has one or more circumferentially inclined narrow grooves having two or more change points of the groove depth.   The pneumatic inclined according to any one of claims 1 to 4, wherein the circumferentially inclined narrow groove has a change amount Dg at a groove depth change point in a range of 2.0 mm ≤ Dg ≤ 6.0 mm. tire.   The pneumatic tire according to any one of claims 1 to 5, wherein the circumferentially inclined narrow groove has one or more circumferentially inclined narrow grooves having two or more change points of the groove width.   The pneumatic tire according to any one of claims 1 to 6, wherein the circumferentially inclined narrow groove has a change amount Wg at a change point of the groove width in a range of 0.5 mm ≤ Wg ≤ 5.0 mm. .   The pneumatic tire according to any one of claims 1 to 7, wherein the first lug groove has one or more change points of the groove width.   The pneumatic tire according to any one of claims 1 to 8, wherein the first lug groove has a change amount W1 at a change point of the groove width in a range of 1.0 mm ≤ W1 ≤ 3.0 mm.   The pneumatic tire according to any one of claims 1 to 9, wherein the second lug groove has one or more change points of the groove width.   11. The pneumatic tire according to claim 1, wherein the second lug groove has a change amount W <b> 2 at a change point of the groove width in a range of 0.5 mm ≦ W <b> 2 ≦ 2.5 mm.

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