JP7298226B2 - tire - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tire having a tread portion with excellent on-snow performance.

Conventionally, a tire having a tread portion suitable for running on a snowy road surface is known. For example, Patent Document 1 below proposes a pneumatic tire having a tread portion divided into blocks by a plurality of main grooves extending continuously in a zigzag shape in the tire circumferential direction and a plurality of lateral grooves communicating between the main grooves. It is The tire of Patent Literature 1 exerts great traction when traveling on a snow-covered road surface, and has excellent performance on snow.

JP 2017-128268 A

However, in the tire of Patent Document 1, heel-and-toe wear, which is partial wear in the tire circumferential direction, may occur at the corners of the blocks divided by the main grooves and the lateral grooves, and there is room for improvement in uneven wear resistance. was there.

SUMMARY OF THE INVENTION The present invention has been devised in view of the actual situation as described above, and a main object of the present invention is to provide a tire capable of achieving both performance on snow and resistance to uneven wear.

The present invention is a tire having a tread portion, wherein the tread portion is formed with a crown land portion divided by a pair of circumferential grooves extending in the tire circumferential direction, and the crown land portion is formed with a pair of grooves extending in the tire circumferential direction. A plurality of crown grooves are provided extending inwardly of the crown land portion from the circumferential groove of the tire, and the crown groove communicates with an outer end portion opening to the circumferential groove and the crown groove adjacent in the tire circumferential direction. The crown land portion includes a plurality of side blocks partitioned between the crown groove and the circumferential groove, and the side blocks are, in a tread plan view, the inner end portion A first corner portion tapered at an acute angle is provided adjacent to the first corner portion, and the first corner portion is provided with a stepped portion extending stepwise inward in the tire radial direction.

In the tire of the present invention, the crown groove includes a first inclined portion extending at an angle to the tire axial direction inside the tire axial direction and a first inclined portion extending along the tire axial direction outside the tire axial direction. It is desirable to include

In the tire of the present invention, it is preferable that a side tie bar is provided on the outer end side of the first axial portion.

In the tire of the present invention, it is preferable that the side tie bars are provided with first tie bar sipes having both ends terminated within the side tie bars.

In the tire of the present invention, it is preferable that the groove width of the first axial portion is smaller than the groove width of the first inclined portion adjacent to the first axial portion.

In the tire of the present invention, it is preferable that a crown tie bar is provided on the inner end side of the first inclined portion.

In the tire of the present invention, the crown groove preferably includes an arc portion extending in an arc shape.

In the tire of the present invention, the crown land portion includes a plurality of side blocks partitioned between the crown groove and the circumferential groove, and the side blocks are adjacent to the inner end portion when viewed from the top of the tread. A tapered first corner is divided by , and the first corner is provided with a stepped portion extending stepwise inward in the tire radial direction.

Such a side block can improve the on-snow performance of the tire by allowing the first corner portion to bite into the snow when driving on a snow-covered road surface. In addition, the stepped portion of the side block prevents the tip of the first corner from contacting the ground when driving on a paved road surface, while increasing edge components when driving on a snow-covered road surface. It is possible to achieve both on-snow performance and uneven wear resistance performance.

1 is an exploded view showing an embodiment of a tread portion of a tire of the present invention; FIG. It is an enlarged view of the center part of the crown land part. It is an enlarged view of the side block of a crown land part. It is an enlarged view of a circumferential groove. FIG. 11 is an enlarged view of a circumferential groove of another embodiment;

An embodiment of the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a developed view showing a tread portion 2 of a tire 1 of this embodiment. As shown in FIG. 1, the tire 1 of this embodiment is suitably used as a pneumatic tire having a tread portion 2 suitable for running on a snowy road surface.

The tire 1 may be used as a pneumatic tire for running on uneven road surfaces such as muddy ground, in addition to road surfaces on snow. Moreover, the tire 1 is not limited to a pneumatic tire, and may be, for example, a non-pneumatic tire in which the inside of the tire 1 is not filled with pressurized air.

A plurality of circumferential grooves 3 extending in the tire circumferential direction and a plurality of land portions 4 partitioned by the circumferential grooves 3 are formed in the tread portion 2 of the present embodiment. For example, one circumferential groove 3 is formed between the tire equator C and the tread edge Te.

Here, in the case of a pneumatic tire, the tread edge Te is the outermost contact point in the tire axial direction when the tire 1 in a normal state is applied with a normal load and is grounded on a flat surface with a camber angle of 0°. A central position in the tire axial direction between the tread edges Te is the tire equator C. As shown in FIG.

"Normal state" is a no-load state in which the tire 1 is mounted on a normal rim and adjusted to a normal internal pressure. Hereinafter, unless otherwise specified, the dimensions and the like of each part of the tire 1 are values measured in this normal state.

A "regular rim" is a rim defined for each tire in a standard system including the standard on which the tire 1 is based. Then it is "Measuring Rim".

"Normal internal pressure" is the air pressure determined for each tire by each standard in the standard system including the standards on which the tire 1 is based. AT VARIOUS COLD INFLATION PRESSURES" is the maximum value, and ETRTO is "INFLATION PRESSURE".

"Normal load" is the load defined for each tire by each standard in the standard system including the standards on which the tire 1 is based. LIMITS AT VARIOUS COLD INFLATION PRESSURES", or "LOAD CAPACITY" for ETRTO.

The tread portion 2 of this embodiment is formed with a crown land portion 4A defined by a pair of circumferential grooves 3 and a shoulder land portion 4B defined by the circumferential grooves 3 and the tread edge Te. Thus, the land portion 4 of this embodiment includes the crown land portion 4A and the shoulder land portion 4B.

The circumferential grooves 3 are preferably formed in a zigzag shape in the tire circumferential direction. Such circumferential grooves 3 can improve drainage performance when driving on wet road surfaces while maintaining traction when driving on snow road surfaces, and achieve both snow performance and wet performance of the tire 1. be able to.

The crown land portion 4A of the present embodiment is provided with a plurality of crown grooves 9 extending from the pair of circumferential grooves 3 toward the inside of the crown land portion 4A. Each of the plurality of crown grooves 9 includes, for example, an outer end portion 9a that opens into the circumferential groove 3 and an inner end portion 9b that communicates with the crown groove 9 adjacent in the tire circumferential direction. The crown groove 9 of the present embodiment extends continuously in the tire circumferential direction as a whole by the plurality of crown grooves 9 without crossing the tire equator C. As shown in FIG.

The crown land portion 4A includes a center portion 4a partitioned between the axially adjacent crown grooves 9 and a plurality of side blocks 4b partitioned between the crown grooves 9 and the circumferential grooves 3. is desirable. In this embodiment, one side block 4 b is formed corresponding to one crown groove 9 .

Preferably, the crown groove 9 is alternately provided with a plurality of wide regions 9A having a large groove width and a plurality of narrow regions 9B having a small groove width. The crown groove 9 of this embodiment has an outer end portion 9a formed as a narrow region 9B and an inner end portion 9b formed as a wide region 9A. Crown groove 9 preferably has at least one pair of widened region 9A and narrowed region 9B between outer end 9a and inner end 9b.

Such a crown groove 9 can reduce the viscosity between the groove wall of the crown groove 9 and the water in the crown groove 9 , thereby improving the wet performance of the tire 1 . Further, since the crown groove 9 is formed by repeating the wide area 9A and the narrow area 9B, the rigidity of the crown land portion 4A can be made uniform, and the uneven wear resistance performance of the tire 1 can be improved. can.

At least one of the wide regions 9A is desirably formed as a variable region in which the groove width changes within the wide region 9A. At least one of the narrow regions 9B is desirably formed as a variable region in which the groove width changes within the narrow region 9B. The wide area 9A and the narrow area 9B may include, for example, constant areas in which the groove width does not change within each range. The outer end portion 9a of this embodiment is formed as a constant area. On the other hand, the inner end portion 9b is preferably formed as a change region.

Here, the boundary between the wide area 9A and the narrow area 9B is a portion where at least one of the groove walls of the crown groove 9 changes abruptly. Further, when both the wide area 9A and the narrow area 9B are formed as changing areas, the boundary between the wide area 9A and the narrow area 9B may be an intermediate portion where the boundary changes gently. Such wide regions 9A and narrow regions 9B can further reduce the viscosity between the groove walls and water, and can further improve the wet performance of the tire 1 .

FIG. 2 is an enlarged view of the center portion 4a of the crown land portion 4A. As shown in FIG. 2, the crown groove 9 is preferably formed in a zigzag shape with a plurality of bends 9c. The crown groove 9 includes, for example, an arc portion 9d extending arcuately between the bent portions 9c. Here, the shape of the crown groove 9 is determined based on the center line of the crown groove 9 in the groove width direction, and one of the groove walls changes like the boundary between the wide area 9A and the narrow area 9B. It is assumed that the center line of the part where the

Such a crown groove 9 suppresses pattern noise when driving on a paved road surface, and can exert a large traction when driving on a snowy road surface, thereby achieving both snow performance and noise performance of the tire 1. be able to.

The center portion 4a of this embodiment includes a center lateral groove 5 extending between the axially adjacent crown grooves 9, a center sipe 6 extending between the axially adjacent crown grooves 9, and a groove extending from the crown groove 9. A center notch 7 recessed inward in the tire axial direction is provided. Such a center portion 4a can suppress heel-and-toe wear and chipping when driving on a paved road surface and increase the edge component when driving on a snowy road surface. can be compatible.

The center portion 4a of this embodiment is divided into a plurality of center blocks 4c by a plurality of center lateral grooves 5. As shown in FIG. A plurality of center sipes 6 and a plurality of center notches 7 are preferably provided in each of the center blocks 4c. Such a center block 4c can further increase edge components when traveling on a snowy road surface, and can further improve the performance of the tire 1 on snow.

The center lateral groove 5 includes, for example, a pair of center end portions 5a communicating with axially adjacent crown grooves 9 . A center tie bar 8 is preferably provided on at least one side of the pair of center end portions 5 a of the center lateral groove 5 . The center lateral groove 5 of this embodiment is provided with center tie bars 8 at the center end portions 5a on both sides. Such a center lateral groove 5 can improve the rigidity of the center block 4c by the center tie bar 8, suppress heel-and-toe wear and chipping of the center block 4c, and improve the uneven wear resistance performance of the tire 1.

The depth of the center lateral groove 5 at the center end 5a is preferably 30% to 60% of the maximum depth of the crown groove 9. If the depth at the center end portion 5a is less than 30% of the maximum depth of the crown groove 9, the snow column formed by the center lateral groove 5 will be small, and the effect of improving the on-snow performance of the tire 1 may be reduced. be. If the depth at the center end portion 5a is greater than 60% of the maximum depth of the crown groove 9, the rigidity of the center block 4c will not be improved, and there is a risk that the effect of improving the uneven wear resistance performance of the tire 1 will be reduced. .

The center sipe 6 has, for example, ends 6a on both sides in the tire axial direction. At least one of the ends 6 a of the center sipe 6 preferably communicates with the center notch 7 . Such a center sipe 6 can easily deform the center block 4c when the center block 4c touches the ground, improve snow removal performance of the crown groove 9, and improve performance of the tire 1 on snow.

The center sipe 6 of this embodiment includes a first center sipe 6A having both ends 6a communicating with the center notch 7, and one end 6a communicating with the center notch 7 and the other end 6a being bent. and a second center sipe 6B communicating with the portion 9c. Since both ends 6a of the center sipe 6 communicate with the center notch 7 or the bent portion 9c, the center block 4c can be deformed more easily, and the on-snow performance of the tire 1 can be further improved. .

The center sipe 6 has, for example, the depth of the end portions 6a on both sides smaller than the maximum depth of the central portion of the center sipe 6 . The depth of the end portion 6a of the center sipe 6 is preferably 20% to 40% of the maximum depth of the crown groove 9. If the depth of the end portion 6a is less than 20% of the maximum depth of the crown groove 9, the deformation of the center block 4c will be difficult even when the center block 4c touches the ground. If the depth of the end portion 6a is larger than 40% of the maximum depth of the crown groove 9, the rigidity of the center block 4c is lowered, and heel-and-toe wear and chipping may occur.

The maximum depth of the center notch 7 is desirably equal to or greater than the depth of the end 6a of the center sipe 6. If the maximum depth of the center cutout portion 7 is smaller than the depth of the end portion 6a of the center sipe 6, the center cutout portion 7 will disappear faster than the center sipe 6 due to wear during continuous use, and the crown groove 9 will disappear. There is a risk that the snow removal performance of the

FIG. 3 is an enlarged view of the side block 4b of the crown land portion 4A. As shown in FIG. 3, the crown groove 9 that divides the side block 4b of the present embodiment includes a first inclined portion 9C that extends on the inner side in the tire axial direction and is inclined with respect to the tire axial direction, and a first inclined portion 9C that extends in the axial direction. and a first axial portion 9D extending along the axial direction of the tire on the outer side.

It is desirable that the first inclined portion 9C extends in a zigzag shape along the tire circumferential direction from the inner end portion 9b. The first axial portion 9D preferably extends linearly along the tire axial direction from the outer end portion 9a. Since the first inclined portion 9C and the first axial portion 9D are bent in such a crown groove 9, a strong snow column can be formed, and the on-snow performance of the tire 1 can be improved. .

A crown tie bar 17 is provided on the inner end portion 9b side of the first inclined portion 9C of the present embodiment. The crown tie bar 17 is formed, for example, from the inner end portion 9b to a first side notch portion 16A, which will be described later. Such a crown tie bar 17 can increase the rigidity of the side block 4 b and improve the uneven wear resistance performance of the tire 1 .

The length of the crown tie bars 17 is preferably 20% to 40% of the pitch length between adjacent crown tie bars 17 in the tire circumferential direction. The height of the crown tie bar 17 from the groove bottom of the crown groove 9 is preferably 50% to 80% of the maximum depth of the crown groove 9 . Therefore, the depth of the crown groove 9 at the inner end portion 9b is 20% to 50% of the maximum depth of the crown groove 9. FIG. Such a crown tie bar 17 can improve the rigidity of the side block 4b while maintaining excellent drainage performance, and can achieve both wet performance and uneven wear resistance performance of the tire 1. FIG.

A first inclined portion 9C adjacent to the first axial portion 9D is preferably formed as a widened region 9A. Also, the first axial portion 9D is preferably formed as a narrow region 9B. Such first inclined portion 9C and first axial portion 9D can suppress pattern noise when traveling on a paved road surface, and can improve the noise performance of the tire 1 .

The groove width of the first axial portion 9D is preferably 25% to 75% of the groove width of the first inclined portion 9C adjacent to the first axial portion 9D. Such a first axial portion 9D can suppress pattern noise while maintaining the rigidity of the side block 4b, and can achieve both the noise performance of the tire 1 and the uneven wear resistance performance.

A side tie bar 11 is provided on the outer end portion 9a side of the first axial portion 9D of the present embodiment. Such a side tie bar 11 can further improve the rigidity of the side block 4b while suppressing pattern noise, and can achieve both the noise performance of the tire 1 and the uneven wear resistance performance.

The height of the side tie bar 11 from the groove bottom of the crown groove 9 is preferably 50% to 80% of the maximum depth of the crown groove 9 . Therefore, the depth of the crown groove 9 at the outer end portion 9a is 20% to 50% of the maximum depth of the crown groove 9. FIG. Such a side tie bar 11 can improve the rigidity of the side block 4b while suppressing pattern noise, and can achieve both noise performance and uneven wear resistance performance of the tire 1. FIG.

Preferably, the side tie bars 11 are provided with first tie bar sipes 12 terminating in the side tie bars 11 at both ends. Such a first tie bar sipe 12 can increase the edge component when driving on a snowy road surface without increasing the pattern noise when driving on a paved road surface, thereby improving the snow performance and noise performance of the tire 1. can be made compatible.

The depth of the first tie bar sipe 12 is preferably 75% to 100% of the height of the crown groove 9 of the side tie bar 11 from the groove bottom. Such a first tie bar sipe 12 is suitable for improving the on-snow performance and noise performance of the tire 1 in a well-balanced manner.

4 is an enlarged view of the circumferential groove 3. FIG. As shown in FIG. 4, the angle θ1 at the outer end 9a of the crown groove 9 with respect to the axial direction of the tire is preferably 5 to 10°. If the angle θ1 is smaller than 5°, the pattern noise increases, and the effect of improving the noise performance of the tire 1 may decrease. If the angle θ1 is larger than 10°, the snow removal performance of the crown groove 9 may deteriorate, and the effect of improving the performance on snow of the tire 1 may decrease.

As shown in FIG. 3, the side block 4b is preferably provided with a side lateral groove 10 extending axially inward from the circumferential groove 3 and terminating within the side block 4b. The side lateral groove 10 of this embodiment includes a second inclined portion 10A extending on the inner side in the tire axial direction and inclined with respect to the axial direction, and a second axial portion 10A extending along the axial direction on the outer side in the tire axial direction. 10B. Since the second inclined portion 10A and the second axial portion 10B of the side lateral groove 10 are bent, a strong snow column can be formed, and the on-snow performance of the tire 1 can be improved. .

In the tread plan view, the side block 4b of the present embodiment is formed by two crown grooves 9 adjacent to each other in the tire circumferential direction. 4d is preferably partitioned. Such a first corner portion 4d bites into the snow when traveling on a snow-covered road surface, and can improve the performance of the tire 1 on snow.

A stepped portion 13 extending stepwise inward in the tire radial direction is provided at the first corner portion 4d of the present embodiment. The stepped portion 13 has two or more steps, and three steps in this embodiment. Such a stepped portion 13 can increase edge components when traveling on a snow-covered road surface while suppressing the tip of the first corner portion 4d from contacting the ground when traveling on a paved road surface. It is possible to achieve both performance and uneven wear resistance.

A first side wall 4e extending along the circumferential groove 3 is formed in the side block 4b. The first side wall 4e is provided with a stepped portion 14 extending stepwise inward in the tire radial direction. The stepped portion 14 has, for example, three stepped portions. The stepped portion 14 is preferably provided adjacent to the outer end portion 9a of the crown groove 9. As shown in FIG. Such a stepped portion 14 can increase the edge component in the tire axial direction when traveling on a snowy road surface, and can improve the on-snow performance of the tire 1 . In addition, the stepped portion 14 can reduce the viscosity of the water in the crown groove 9 and further improve the wet performance of the tire 1 .

The side block 4b is preferably provided with a plurality of side sipes 15 extending from the circumferential groove 3 to the crown groove 9, and side notches 16 recessed outward from the crown groove 9 in the tire axial direction. The side sipe 15 communicates with the side notch 16 at the end 15a on the side of the crown groove 9, for example. Such a side sipe 15 can easily deform the side block 4b when the side block 4b touches the ground, improve the snow removal performance of the crown groove 9, and improve the performance of the tire 1 on snow.

Side sipes 15 preferably include a first side sipe 15A extending from first side wall 4e. The side notch 16 preferably includes a first side notch 16A with which the first side sipe 15A communicates. Both sides of the first side sipe 15A are communicated with the first side wall 4e and the side notch 16, so that the side block 4b can be deformed more easily, and the on-snow performance of the tire 1 can be further improved.

As shown in FIG. 1, the shoulder land portion 4B includes, for example, a shoulder lateral groove 18 extending from the circumferential groove 3 to the tread edge Te, and a shoulder lateral groove 18 extending axially outward from the circumferential groove 3 and within the shoulder land portion 4B. Terminating shoulder sipes 19 are provided.

The shoulder land portion 4B of the present embodiment is divided into shoulder blocks 4f by a plurality of shoulder lateral grooves 18. As shown in FIG. A plurality of shoulder sipes 19 are desirably provided in each of the shoulder blocks 4f. Such shoulder blocks 4f can increase edge components when driving on a snowy road surface, and can improve the performance of the tire 1 on snow.

The shoulder lateral grooves 18 are preferably formed in a zigzag shape. Such shoulder lateral grooves 18 can reduce pattern noise when running on a paved road surface and improve the noise performance of the tire 1 .

As shown in FIG. 4, the shoulder lateral groove 18 includes a shoulder end portion 18a communicating with the circumferential groove 3 at a position at least partially overlapping the outer end portion 9a in the tire circumferential direction. Such shoulder lateral grooves 18 are smoothly continuous with the crown grooves 9 via the circumferential grooves 3, and can form strong snow columns at intersections with the circumferential grooves 3. It can improve performance.

The length in the tire circumferential direction of the overlapping portion between the shoulder end portion 18a and the outer end portion 9a is preferably 25% or less of the length in the tire circumferential direction of the outer end portion 9a. Such shoulder lateral grooves 18 and crown grooves 9 have few portions that contact the ground at the same time when the vehicle is running, so that the noise performance of the tire 1 can be improved.

A shoulder tie bar 20 is preferably provided on the side of the shoulder end portion 18 a of the shoulder lateral groove 18 . Such a shoulder tie bar 20 can improve the rigidity of the shoulder land portion 4B while maintaining excellent drainage performance, and can achieve both wet performance and uneven wear resistance performance of the tire 1 .

The height of the shoulder lateral groove 18 of the shoulder tie bar 20 from the groove bottom is preferably 50% to 80% of the maximum depth of the shoulder lateral groove 18 . Such a shoulder tie bar 20 can improve the rigidity of the shoulder land portion 4B while suppressing pattern noise, and can achieve both the noise performance of the tire 1 and the uneven wear resistance performance.

The angle θ2 of the shoulder end portion 18a of the shoulder lateral groove 18 with respect to the axial direction of the tire is preferably 5 to 10°. If the angle θ2 is smaller than 5°, the pattern noise increases, and the effect of improving the noise performance of the tire 1 may decrease. If the angle θ2 is larger than 10°, the snow-removal performance may be deteriorated, and the effect of improving the snow performance of the tire 1 may be reduced.

FIG. 5 is an enlarged view of the circumferential groove 3 of another embodiment. Components having functions similar to those of the above-described embodiments are denoted by the same reference numerals, and descriptions thereof are omitted. As shown in FIG. 5, the shoulder lateral groove 18 of this embodiment is aligned with the circumferential groove 3 at a position overlapping 50% or more of the circumferential length of the outer end portion 9a of the crown groove 9 in the tire circumferential direction. It includes a communicating shoulder end 18a. Such shoulder lateral grooves 18 can cooperate with the crown grooves 9 to form strong snow columns at intersections with the circumferential grooves 3, so that the on-snow performance of the tire 1 can be further improved.

A shoulder tie bar 21 is provided on the shoulder end portion 18a side of the shoulder lateral groove 18 of this embodiment. Preferably, the shoulder tie bar 21 is provided with a second tie bar sipe 22 terminating in the shoulder tie bar 21 at both ends. Such a second tie bar sipe 22 can increase edge components when traveling on a snowy road surface without increasing pattern noise, and can achieve both snow performance and noise performance of the tire 1.例文帳に追加

The depth of the second tie bar sipe 22 is preferably 75% to 100% of the height of the shoulder lateral groove 18 of the shoulder tie bar 21 from the groove bottom. Such a second tie bar sipe 22 is suitable for improving the on-snow performance and noise performance of the tire 1 in a well-balanced manner.

Although the particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and can be modified in various ways.

Tires having the basic pattern shown in FIG. Each prototype tire was tested for performance on snow and resistance to uneven wear. Common specifications and test methods for each prototype tire are as follows.

<Common specifications>
Tire size: 265/65R17 112S
Rim size: 17 x 8.0J
Air pressure: 220kPa

<Snow Performance>
One test driver rode a medium-sized SUV test vehicle with prototype tires on all wheels, and measured the distance when accelerating from 5 mph to 20 mph on a compacted snow course. The results are expressed as an index with the comparative example being 100, and the larger the number, the shorter the distance and the better the performance on snow.

<Uneven wear resistance performance>
Using a wear energy measuring device, the wear energy of each portion of the tread portion of the trial tire was measured. The results are expressed as an index with the comparative example being 100. The larger the numerical value, the smaller the variation in wear energy and the better the uneven wear resistance.

The results of the tests are shown in Tables 1 and 2.

As a result of the test, it was confirmed that the tire of the example had improved performance on snow and resistance to uneven wear compared to the comparative example, and that the performance on snow and resistance to uneven wear were compatible.

Reference Signs List 1 tire 2 tread portion 3 circumferential groove 4A crown land portion 4b side block 4d first corner portion 9 crown groove 9a outer end portion 9b inner end portion 13 stepped portion

Claims (5)

A tire having a tread portion,
The tread portion is formed with a crown land portion divided by a pair of circumferential grooves extending in the tire circumferential direction,
The crown land portion is provided with a plurality of crown grooves extending inwardly of the crown land portion from the pair of circumferential grooves,
The crown groove includes an outer end that opens into the circumferential groove and an inner end that communicates with the crown groove adjacent in the tire circumferential direction,
the crown land portion includes a plurality of side blocks partitioned between the crown groove and the circumferential groove;
The side block is divided into a first corner that is tapered at an acute angle adjacent to the inner end in a tread plan view,
The first corner is provided with a stepped portion extending stepwise inward in the tire radial direction ,
The crown groove includes a first inclined portion extending at an angle to the tire axial direction inside the tire axial direction and a first axial portion extending along the tire axial direction outside the tire axial direction,
A side tie bar is provided on the outer end side of the first axial portion ,
tire. 2. The tire of claim 1 , wherein the side tie bars are provided with first tie bar sipes that terminate in the side tie bars at opposite ends. A tire having a tread portion,
The tread portion is formed with a crown land portion divided by a pair of circumferential grooves extending in the tire circumferential direction,
The crown land portion is provided with a plurality of crown grooves extending inwardly of the crown land portion from the pair of circumferential grooves,
The crown groove includes an outer end that opens into the circumferential groove and an inner end that communicates with the crown groove adjacent in the tire circumferential direction,
the crown land portion includes a plurality of side blocks partitioned between the crown groove and the circumferential groove;
The side block is divided into a first corner that is tapered at an acute angle adjacent to the inner end in a tread plan view,
The first corner is provided with a stepped portion extending stepwise inward in the tire radial direction,
The crown groove includes a first inclined portion extending at an angle to the tire axial direction inside the tire axial direction and a first axial portion extending along the tire axial direction outside the tire axial direction,
the groove width of the first axial portion is smaller than the groove width of the first inclined portion adjacent to the first axial portion;
tire. A tire having a tread portion,
The tread portion is formed with a crown land portion divided by a pair of circumferential grooves extending in the tire circumferential direction,
The crown land portion is provided with a plurality of crown grooves extending inwardly of the crown land portion from the pair of circumferential grooves,
The crown groove includes an outer end that opens into the circumferential groove and an inner end that communicates with the crown groove adjacent in the tire circumferential direction,
the crown land portion includes a plurality of side blocks partitioned between the crown groove and the circumferential groove;
The side block is divided into a first corner that is tapered at an acute angle adjacent to the inner end in a tread plan view,
The first corner is provided with a stepped portion extending stepwise inward in the tire radial direction,
The crown groove includes a first inclined portion extending at an angle to the tire axial direction inside the tire axial direction and a first axial portion extending along the tire axial direction outside the tire axial direction,
A crown tie bar is provided on the inner end side of the first inclined portion,
tire. The tire according to any one of claims 1 to 4 , wherein the crown groove includes an arc portion extending in an arc shape.

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