JP2017178170A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve uneven wear resistance while maintaining durability performance.SOLUTION: The pneumatic tire comprises: at least two circumferential grooves 3 extended along a tire circumferential direction and provided parallely in a tire width direction; a plurality of width-directional grooves 4, extended crossing the tire circumferential direction and provided parallely in the tire circumferential direction, both ends of which communicate with the circumferential grooves 3 and compart and form block-shape land parts 5 between the circumferential grooves 3; and two narrow grooves 6, extended along the tire circumferential direction and provided parallely in the tire width direction in the land part 5, both ends of which communicate with the width-directional grooves 4 and divide the land parts 5, comparted and formed by the circumferential grooves 3 and the width-directional grooves 4, into a plurality of small land parts 5A and 5B, in the tire width direction. In the land parts 5, the two narrow grooves 6 are formed smaller in groove width than the circumferential grooves 3, in which bent parts 6A are formed at the middle and the bent parts 6A are arranged closer to insides opposing to each other in the tire width direction than virtual lines A both ends of which are connected, and bent points 6Aa of mutual bent parts 6A are arranged to be positionally deviated from each other in the tire circumferential direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire.

  In a general tire, if the pressure at the time of ground contact is high, it causes uneven wear, and therefore it is necessary to moderate the contact pressure properly.

  Conventionally, for example, Patent Document 1 describes a pneumatic tire aimed at improving on-snow maneuvering stability after wear caused by running without impairing dry maneuvering stability. In this pneumatic tire, a tread portion has a tread portion having a plurality of main grooves extending in the circumferential direction and a block partitioned by a transverse groove intersecting with the main groove. A pair of acute block corners opposed in the circumferential direction, and a pair of small blocks defined by the pair of acute block corners and two sipes, and sandwiched between the small blocks; And a central block larger than the small block.

JP 2003-182315 A

  Inserting narrow grooves or slits such as sipes may weaken the rigidity of the blocks and ribs and cause baldness and chipping.

  The present invention has been made in view of the above, and by reducing the ground pressure while maintaining block rigidity, a pneumatic tire capable of improving uneven wear resistance while maintaining durability performance. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, a pneumatic tire according to one aspect of the present invention includes two circumferential tires extending along the tire circumferential direction on the tread surface of the tread portion and aligned in the tire width direction. A plurality of directional grooves, extending in the tire circumferential direction on the tread surface and arranged side by side in the tire circumferential direction, with both ends communicating with the circumferential grooves and blocking between the circumferential grooves. A widthwise groove that defines a land portion in the form of a ring, and two grooves extending in the tire circumferential direction on the tread surface of the land portion and arranged side by side in the tire width direction, and both ends communicate with each widthwise groove. And a narrow groove that divides the land portion defined by each circumferential groove and each width direction groove into a plurality of small land portions in the tire width direction. The narrow groove has a groove width smaller than that of the circumferential groove, Bending portions are formed, the bending portions are arranged inside the tire width direction facing each other with respect to a virtual straight line connecting both ends, and the bending points of the bending portions are displaced in the tire circumferential direction. Has been placed.

  According to this pneumatic tire, each land portion defined by the circumferential groove and the width direction groove is divided into a plurality of small land portions by two narrow grooves, thereby reducing rigidity. As a result, the ground pressure at the time of grounding of the tread portion is relieved. Furthermore, each fine groove has a bent portion and is formed by bending to extend the length, thereby further reducing the ground pressure by further reducing the rigidity. For this reason, uneven wear-resistant performance can be improved. In addition, according to this pneumatic tire, the bent portion is arranged on the inner side in the tire width direction where the two narrow grooves are opposed to each other with respect to the virtual straight line connecting both ends of the narrow groove. The area on the tread surface is reduced, and the rigidity is prevented from decreasing. Further, by disposing the mutual bending points of the two narrow grooves in the circumferential direction of the tire, the central small land portion is suppressed from being locally narrowed, and the rigidity is prevented from being lowered. For this reason, generation | occurrence | production of the baldness and a chip of a land part can be suppressed. As a result, according to this pneumatic tire, uneven wear resistance can be improved while suppressing the occurrence of baldness and chipping and maintaining durability.

  In the pneumatic tire according to one aspect of the present invention, the narrow groove preferably has a bending angle of the bent portion in a range of 90 ° to 160 °.

  According to this pneumatic tire, if the bending angle of the bent portion is 90 ° or more, the bending becomes an acute angle or more, so that baldness and chipping hardly occur and the effect of maintaining durability is great. On the other hand, if the bending angle of the bent portion is 160 ° or less, the effect of reducing the rigidity by extending the length of the narrow groove is great.

  Further, in the pneumatic tire according to one aspect of the present invention, the deviation width Lc in the tire circumferential direction between the bending points of the two narrow grooves has a tire circumference of the land portion where the narrow grooves are formed. It is preferable that 0.1 ≦ Lc / L with respect to the direction dimension L.

  According to this pneumatic tire, by setting 0.1 ≦ Lc / L, it is further suppressed that the central small land portion between the two narrow grooves is locally thinned, and further prevents a decrease in rigidity. It is possible to maintain durability performance.

  Further, in the pneumatic tire according to one aspect of the present invention, the width direction groove is formed so as to be inclined and extend with respect to the tire width direction, and an angle with respect to the tire width direction is not less than 5 ° and not more than 50 °. It is preferable that it is the range of these.

  According to this pneumatic tire, when the angle of the width direction groove is 5 ° or more, the effect of increasing the width of the width direction groove and reducing the rigidity is great. If the angle of the width direction groove is 50 ° or less, in order to prevent the corner from becoming sharp, baldness and chipping are less likely to occur, and the effect of maintaining durability is great.

  In the pneumatic tire according to one aspect of the present invention, when the groove depth of the circumferential groove is Ha, the groove depth of the width direction groove is Hb, and the groove depth of the narrow groove is Hc, Ha It is preferable to satisfy the relationship of> Hb and Ha> Hc.

  According to this pneumatic tire, by reducing the groove depth Hb of the widthwise groove and the groove depth Hc of the narrow groove to be smaller than the groove depth Ha of the circumferential groove, the rigidity of the land portion in the tire circumferential direction is reduced. Therefore, the effect of maintaining durability is great.

  In the pneumatic tire according to one aspect of the present invention, when the groove depth of the widthwise groove is Hb and the groove depth of the narrow groove is Hc, Hb is 1 mm or more and 5 mm or less, and Hc is 1 mm. It is preferable that it is 5 mm or less.

  According to this pneumatic tire, since the groove depth Hb of the width direction groove and the groove depth Hc of the narrow groove are set to 1 mm or more and 5 mm or less, the rigidity of the land portion is suppressed, so durability is maintained. Great effect.

  Moreover, in the pneumatic tire according to one aspect of the present invention, the widthwise groove is formed so as to be inclined and extend with respect to the tire width direction, and has an acute angle with respect to the tire circumferential direction. It is preferable that chamfers are formed at the corners.

  According to this pneumatic tire, by providing chamfering, baldness and chipping hardly occur and the effect of maintaining durability is great.

  The pneumatic tire according to an aspect of the present invention further includes a sipe formed with one end communicating with the circumferential groove and the other end terminating in the land portion on the tread surface, and the groove width of the sipe Is Wd, the groove depth is Hd, the groove length is Ld, the tire width direction dimension of the land portion is We, and the groove depth of the circumferential groove is Ha, 0.3 mm ≦ Wd ≦ 2. It is preferable that the relationship of 0 mm, 0.3 ≦ Hd / Ha ≦ 1.0, 0.03 ≦ Ld / We ≦ 0.2 is satisfied.

  According to this pneumatic tire, the rigidity of the land portion is reduced by sipe and the contact pressure is relieved, so that the effect of improving uneven wear resistance is great.

  According to the present invention, uneven wear resistance can be improved while maintaining durability.

FIG. 1 is a plan view of a tread portion of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is an enlarged view of a tread portion of the pneumatic tire according to the embodiment of the present invention. FIG. 3 is an enlarged view of a tread portion of another example of the pneumatic tire according to the embodiment of the present invention. FIG. 4 is an enlarged view of a tread portion of another example of the pneumatic tire according to the embodiment of the present invention. FIG. 5 is an enlarged cross-sectional view of a tread portion of the pneumatic tire according to the embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view of the tread portion of the pneumatic tire according to the embodiment of the present invention. FIG. 7 is a chart showing the results of the performance test of the pneumatic tire according to the example of the present invention. FIG. 8 is a chart showing the results of the performance test of the pneumatic tire according to the example of the present invention.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. The constituent elements of this embodiment include those that can be easily replaced by those skilled in the art or those that are substantially the same. Further, a plurality of modifications described in this embodiment can be arbitrarily combined within the scope obvious to those skilled in the art.

  FIG. 1 is a plan view of a tread portion of a pneumatic tire according to the present embodiment. FIG. 2 is an enlarged view of a tread portion of the pneumatic tire according to the present embodiment. FIG. 3 is an enlarged view of a tread portion of another example of the pneumatic tire according to the present embodiment. FIG. 4 is an enlarged view of a tread portion of another example of the pneumatic tire according to the present embodiment. FIG. 5 is an enlarged cross-sectional view of the tread portion of the pneumatic tire according to the present embodiment. FIG. 6 is an enlarged cross-sectional view of the tread portion of the pneumatic tire according to the present embodiment.

  In the following description, the tire circumferential direction refers to a circumferential direction having a rotation axis (not shown) of the pneumatic tire 1 as a central axis. Further, the tire width direction refers to a direction parallel to the rotation axis, the inner side in the tire width direction is the side toward the tire equatorial plane (not shown) in the tire width direction, and the outer side in the tire width direction is in the tire width direction. The side away from the tire equator. The tire radial direction refers to a direction orthogonal to the rotation axis, the inner side in the tire radial direction refers to the side toward the rotation axis in the tire radial direction, and the outer side in the tire radial direction refers to the side away from the rotation axis in the tire radial direction. The tire equator plane is a plane that is orthogonal to the rotation axis and passes through the center of the tire width of the pneumatic tire 1.

  The pneumatic tire 1 of the present embodiment has a tread portion 2 as shown in FIG. The tread portion 2 is made of a rubber material, and is exposed at the outermost side in the tire radial direction of the pneumatic tire 1, and the surface thereof becomes the contour of the pneumatic tire 1 as a tread surface 2 </ b> A.

  In the tread portion 2, a plurality of circumferential grooves 3 extending along the tire circumferential direction are provided on the tread surface 2 </ b> A in a row in the tire width direction (seven in this embodiment are shown in FIG. 1). The circumferential groove 3 is, for example, a groove width of 8 mm or more and 15 mm or less (Wa in FIGS. 2 and 5) and a groove depth of 10 mm or more and 28 mm or less (a dimension from the opening position of the tread surface 2A to the groove bottom: FIG. 5 and FIG. 6 Ha).

  In the tread portion 2, ribs extending in the tire circumferential direction are partitioned and formed by adjacent circumferential grooves 3 on the tread surface 2 </ b> A. In addition, the tread portion 2 is provided with a plurality of widthwise grooves 4 that intersect the tire circumferential direction and extend in the tire width direction side by side in the tire circumferential direction on the tread surface 2A. Both ends of the width direction groove 4 communicate with the circumferential groove 3. For this reason, each rib partitioned by the circumferential groove 3 is divided by the width groove 4, and a block-like land portion 5 is partitioned between the circumferential grooves 3. The width direction groove 4 is, for example, a groove width of 1 mm or more and 4 mm or less (Wb in FIG. 2) and a groove depth of 1 mm or more and 5 mm or less (a dimension from the opening position of the tread surface 2A to the groove bottom: Hb in FIG. 6). Means things.

  The tread portion 2 is a tread surface 2A, and in each land portion 5 defined by the circumferential groove 3 and the width direction groove 4, a narrow groove 6 extending in the tire circumferential direction has a tire width direction. Two are arranged side by side without crossing. Each narrow groove 6 communicates with the width direction groove 4 at both ends. For this reason, each land portion 5 defined by the circumferential groove 3 and the width direction groove 4 is divided into a plurality of portions in the tire width direction by the respective narrow grooves 6. A central small land portion 5A defined by the narrow grooves 6 and two side small land portions 5B defined by the circumferential grooves 3, the width direction grooves 4 and the narrow grooves 6 are formed. The narrow groove 6 has, for example, a groove width of 1 mm or more and 4 mm or less (Wc in FIGS. 2 and 5) and a groove depth of 1 mm or more and 5 mm or less (dimension from the opening position of the tread surface 2A to the groove bottom: FIG. Hc).

  In the land portion 5, the two narrow grooves 6 are formed such that the groove width Wc is smaller than the groove width Wa of the circumferential groove 3. These narrow grooves 6 are formed with bent portions 6A in the middle. The bent portion 6A is disposed on the inner side in the tire width direction where the two narrow grooves 6 face each other in the tire width direction with respect to the virtual straight line A connecting both ends of the narrow groove 6. Further, these narrow grooves 6 are arranged such that the bending points 6Aa of the mutual bent portions 6A are displaced in the tire circumferential direction.

  As shown in FIG. 2, when the bent portion 6 </ b> A is formed by one bend in one narrow groove 6, the bend point 6 </ b> Aa of the narrow groove 6 has two fine points in the tire width direction. This is a turning point on the inner side in the tire width direction where the grooves 6 face each other.

  Further, as shown in FIG. 3, the bending point 6Aa of the narrow groove 6 is 2 in the tire width direction in the plurality of bendings when the bending part 6A is formed by a plurality of bendings. The bending point is the innermost side in the tire width direction where the two narrow grooves 6 face each other (the inner side in the tire width direction where the two narrow grooves 6 face each other than the reference straight line B).

  Further, as shown in FIG. 4, the bending point 6Aa of the narrow groove 6 is a case where the bent portion 6A is formed by a plurality of bends in one narrow groove 6, and in the tire width direction in the plurality of bends. When there are a plurality of innermost turning points in the tire width direction in which the two narrow grooves 6 are opposed to each other, the center point of the reference straight line C connecting the bending points at both ends in the tire inner circumferential direction. . Therefore, in this case, the bending point 6Aa includes that it does not coincide with the bending point as shown in FIG.

  According to the pneumatic tire 1 of the present embodiment having such a configuration, each land portion 5 defined by the circumferential groove 3 and the width direction groove 4 is separated from the central small land portion 5A by the two narrow grooves 6. By being divided into two side small land portions 5B, the ground pressure at the time of ground contact of the tread portion 2 is relieved by low rigidity. Furthermore, each narrow groove 6 has a bent portion 6A and is bent to increase the length, thereby further reducing the ground pressure by further reducing the rigidity. For this reason, uneven wear-resistant performance can be improved.

  Moreover, according to the pneumatic tire 1 of the present embodiment, the bent portion 6A is disposed on the inner side in the tire width direction where the two narrow grooves 6 are opposed to each other with respect to the virtual straight line A that connects both ends of the narrow grooves 6. Therefore, it is suppressed that the area in the tread surface 2A of the side small land part 5B becomes small, and a rigidity fall is prevented. Further, by disposing the mutual bending points 6Aa of the two narrow grooves 6 while shifting the positions in the tire circumferential direction, the central small land portion 5A is suppressed from being locally narrowed, and the rigidity is prevented from being lowered. For this reason, generation | occurrence | production of the baldness and a chip of the land part 5 can be suppressed.

  As a result, according to the pneumatic tire 1 of the present embodiment, uneven wear resistance can be improved while maintaining the durability by suppressing the occurrence of baldness and chipping.

  In the pneumatic tire 1 of the present embodiment, the narrow groove 6 preferably has a bending angle α of the bending portion 6A in a range of 90 ° to 160 °. As shown in FIGS. 2 to 4, the bending angle α is an angle on the smaller side in bending of the bending portion 6A.

  According to this pneumatic tire 1, if the bending angle α of the bent portion 6A is 90 ° or more, the bending becomes an acute angle or more, so that baldness and chipping hardly occur and the effect of maintaining durability is great. On the other hand, when the bending angle α of the bent portion 6A is 160 ° or less, the effect of increasing the length of the narrow groove 6 and reducing the rigidity is great.

  Further, in the pneumatic tire 1 of the present embodiment, as shown in FIG. 2, the deviation width Lc in the tire circumferential direction between the mutual bending points 6Aa of the two narrow grooves 6 is the land where the respective narrow grooves 6 are formed. It is preferable that 0.1 ≦ Lc / L with respect to the tire circumferential dimension L of the portion 5. The maximum value of the deviation width Lc is in the range of the virtual straight line A or less.

  According to this pneumatic tire, by setting 0.1 ≦ Lc / L, it is further suppressed that the central small land portion 5A between the two narrow grooves 6 is locally narrowed, and further prevents a decrease in rigidity. It is possible to maintain durability performance.

  Moreover, in the pneumatic tire 1 of this embodiment, the width direction groove | channel 4 is inclined and extended with respect to the tire width direction, and angle (beta) with respect to a tire width direction is 5 degrees or more and 50 degrees or less. A range is preferable.

  According to this pneumatic tire 1, if the angle β of the width direction groove 4 with respect to the tire width direction is 5 ° or more, the effect of increasing the length of the width direction groove 4 and reducing the rigidity is great. If the angle β of the width direction groove 4 with respect to the tire width direction is 50 ° or less, it becomes difficult to generate baldness and chipping in order to suppress sharpening of the angle, and the effect of maintaining durability is great.

  In the pneumatic tire 1 of the present embodiment, the widthwise grooves 4 are provided in the ribs defined by the adjacent circumferential grooves 3 so as to be inclined in the same direction with respect to the tire width direction. And in the pneumatic tire 1 of this embodiment, the width direction groove | channel 4 is inclined and provided in the same direction with respect to the tire width direction also in the adjacent rib. By comprising in this way, the shape of each land part 5 is fixed, and it contributes to the improvement of uneven wear resistance.

  Further, in the pneumatic tire 1 of the present embodiment, when the groove depth of the circumferential groove 3 is Ha, the groove depth of the widthwise groove 4 is Hb, and the groove depth of the narrow groove 6 is Hc, Ha> Hb , Ha> Hc is preferably satisfied.

  According to the pneumatic tire 1, the tire of the land portion 5 is obtained by making the groove depth Hb of the widthwise groove 4 and the groove depth Hc of the narrow groove 6 smaller than the groove depth Ha of the circumferential groove 3. In order to suppress a decrease in rigidity in the circumferential direction, the effect of maintaining durability is great.

  Moreover, in the pneumatic tire 1 of this embodiment, when the groove depth of the width direction groove | channel 4 is Hb and the groove depth of the narrow groove 6 is Hc, Hb is 1 mm or more and 5 mm or less, and Hc is 1 mm or more and 5 mm or less. The following is preferable.

  According to this pneumatic tire 1, since the groove depth Hb of the widthwise groove 4 and the groove depth Hc of the narrow groove 6 are 1 mm or more and 5 mm or less, a decrease in rigidity of the land portion 5 is suppressed. Great effect of maintaining sex.

  Moreover, in the pneumatic tire 1 of this embodiment, the width direction groove | channel 4 is inclined and extended with respect to the tire width direction, and is an angle of the land part 5 which becomes an acute angle with respect to a tire circumferential direction. It is preferable that chamfer 4A is formed in the part.

  According to this pneumatic tire 1, by providing the chamfer 4A, baldness and chipping are less likely to occur, and the effect of maintaining durability is great.

  In the pneumatic tire 1 of the present embodiment, as shown in FIGS. 2 to 5, one end of the tread surface 2 </ b> A communicates with the circumferential groove 3 and the other end does not intersect the narrow groove 6. It is preferable to further include a sipe 7 formed by terminating at. When the groove width is Wd, the groove depth is Hd, the groove length is Ld, the tire width direction dimension of the land portion 5 is We, and the groove depth of the circumferential groove 3 is Ha. The relationship of 3 mm ≦ Wd ≦ 2.0 mm, 0.3 ≦ Hd / Ha ≦ 1.0, 0.03 ≦ Ld / We ≦ 0.2 is satisfied.

  According to the pneumatic tire 1, the sipe 7 reduces the rigidity of the land portion 5 and relieves the contact pressure, so that the effect of improving uneven wear resistance is great.

  In this example, performance tests on uneven wear resistance and durability performance were performed on a plurality of types of test tires having different conditions (see FIGS. 7 and 8).

  In this performance test, a pneumatic tire with a tire size of 445 / 50R22.5 (pneumatic tire for heavy load) is assembled to a regular rim, filled with regular internal pressure, and used as a trailer shaft for a test vehicle (2-D / D vehicle). Installed.

  Here, 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 performance test related to uneven wear resistance, the area and depth of uneven wear occurring on the land are measured after the test vehicle travels 100,000 miles (about 160,000 km). Then, based on this measurement result, index evaluation using the conventional example as a reference (100) is performed. In this evaluation, the larger the value, the better the uneven wear resistance.

  In the performance test related to the durability performance, the number of baldness and chips generated on the land is measured after the test vehicle travels 100,000 miles (about 160,000 km). Then, based on this measurement result, index evaluation using the conventional example as a reference (100) is performed. In this evaluation, the larger the numerical value, the fewer the number of baldness and chips, and the better the durability performance is.

  The conventional pneumatic tire shown in FIG. 7 does not have a narrow groove. The pneumatic tire of each comparative example shown in FIG. 7 has a narrow groove, but the form of the narrow groove is different from that of the present example. On the other hand, in the pneumatic tire of each example shown in FIGS. 7 and 8, the form of the narrow groove is within the specified range.

  As shown in the test results of FIGS. 7 and 8, it can be seen that the pneumatic tires of Examples 1 to 12 have improved uneven wear resistance while maintaining durability.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 2A Tread surface 3 Circumferential groove 4 Width direction groove 4A Chamfer 5 Land part 5A Central small land part 5B Side small land part 6 Fine groove 6A Bending part 6Aa Bending point 7 Sipe A Virtual straight line

Claims (8)

Two circumferential grooves extending along the tire circumferential direction on the tread surface of the tread portion and arranged in the tire width direction;
The tread surface extends across the tire circumferential direction and is provided side by side in the tire circumferential direction. Both ends communicate with the circumferential grooves, and a block-shaped land portion is provided between the circumferential grooves. A widthwise groove that partitions
The tread surface of the land portion extends along the tire circumferential direction and is provided side by side in the tire width direction. Both ends communicate with the width direction grooves, and the circumferential grooves and the width direction grooves. And a narrow groove that divides the land portion partitioned into a plurality of small land portions in the tire width direction, and
With
In the land portion, the two narrow grooves are formed with a groove width smaller than that of the circumferential groove, a bent portion is formed in the middle, and in the tire width direction facing each other than a virtual straight line connecting both ends. A pneumatic tire in which the bent portions are arranged on the inner side and the bending points of the bent portions are displaced from each other in the tire circumferential direction.   2. The pneumatic tire according to claim 1, wherein the narrow groove has a bending angle of the bent portion of 90 ° or more and 160 ° or less.   The deviation width Lc in the tire circumferential direction of the bending point between the two narrow grooves is 0.1 ≦ Lc / L with respect to the tire circumferential dimension L of the land portion where each of the narrow grooves is formed. The pneumatic tire according to claim 1 or 2, wherein   The said width direction groove | channel is inclined and extended with respect to the tire width direction, and the angle with respect to a tire width direction is the range of 5 degrees or more and 50 degrees or less, The any one of Claims 1-3. Pneumatic tire described in one.   The relationship of Ha> Hb and Ha> Hc is satisfied, where Ha is the groove depth of the circumferential groove, Hb is the groove depth of the width direction groove, and Hc is the groove depth of the narrow groove. The pneumatic tire as described in any one of -4.   The groove depth of the width direction groove is Hb, and the groove depth of the narrow groove is Hc, Hb is 1 mm or more and 5 mm or less, and Hc is 1 mm or more and 5 mm or less. The pneumatic tire according to one.   The width direction groove is formed to be inclined and extend with respect to the tire width direction, and a chamfer is formed at a corner portion of the land portion that has an acute angle with respect to the tire circumferential direction. The pneumatic tire according to any one of 1 to 6. The tread surface further comprises a sipe formed with one end communicating with the circumferential groove and the other end terminating in the land portion,
When the groove width of the sipe is Wd, the groove depth is Hd, the groove length is Ld, the tire width direction dimension of the land portion is We, and the groove depth of the circumferential groove is Ha, 0.3 mm Pneumatic as described in any one of Claims 1-7 satisfy | filling the relationship of <= Wd <= 2.0mm, 0.3 <= Hd / Ha <= 1.0, 0.03 <= Ld / We <= 0.2. tire.

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