JP6863495B1 - tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve local wear resistance in a tire provided with a crossing sipe on land. A tire having a tread portion 2. The tread portion 2 includes the first land portion 11. The first land portion 11 includes at least one transverse sipe 20 extending from the first vertical edge 11a to the second vertical edge 11b. In the transverse sipe 20, at least one of the sipe edge portions on both sides is formed by the chamfered portion 25. The chamfer width W2 of the chamfered portion 25 increases from the intermediate region of the transverse sipe 20 in the tire axial direction toward the first end 20a and the second end 20b. The transverse sipe 20 has a first raised portion 31 having a raised bottom surface on the first end 20a side, a second raised portion 32 having a raised bottom surface on the second end 20b side, and a first raised portion 31 and a second raised portion 32. Includes a third raised portion 33 with a raised bottom surface. [Selection diagram] Fig. 1

Description

The present invention relates to a tire.

Conventionally, various tires provided with sipes on the land have been proposed (see, for example, Patent Document 1 below). Sipe helps improve wet performance.

International Publication WO2016 / 125814

By the way, when a transverse sipe is provided on the land portion, local wear tends to occur on the sipe edge portion. A tire in which the sipe edge portion is used as a chamfered portion has also been proposed, but the above wear has not been solved yet, and further improvement has been required.

The present invention has been devised in view of the above problems, and a main object of the present invention is to improve local wear resistance in a tire provided with a crossing sipe on land.

The present invention is a tire having a tread portion, and the tread portion includes a first land portion having a tread between a first vertical edge and a second vertical edge extending in the tire circumferential direction, and the first land portion. Includes at least one transverse sipe extending from the first longitudinal edge to the second longitudinal edge, wherein the transverse sipe is formed by at least one of the sipe edge portions on both sides being a chamfered portion. The chamfer width increases from the intermediate region in the tire axial direction of the sipe toward the first end on the first vertical edge side and the second end on the second vertical edge side, and the crossing sipe has the first end. A first raised portion having a raised bottom surface on the side, a second raised portion having a raised bottom surface on the second end side, and a third raised portion having a raised bottom surface between the first raised portion and the second raised portion. Including the part.

In the tire of the present invention, it is desirable that the transverse sipe includes a portion inclined with respect to the tire axial direction.

In the tire of the present invention, it is desirable that the transverse sipe includes a portion inclined at an angle of 5 to 45 ° with respect to the tire axial direction.

In the tire of the present invention, it is desirable that the first land portion is provided with a plurality of the crossing sipes, and the crossing sipes include those having different maximum inclination angles with respect to the tire axial direction.

In the tire of the present invention, it is desirable that the difference in the inclination angles of the transverse sipe is 5 to 15 °.

In the tire of the present invention, it is desirable that each of the sipe edge portions on both sides of the transverse sipe is formed by the chamfered portion.

In the tire of the present invention, the maximum value of the chamfer width is preferably 1.0 to 1.5 mm.

In the tire of the present invention, it is desirable that the difference between the maximum value and the minimum value of the chamfer width is less than 1.5 mm.

In the tire of the present invention, it is desirable that the height of the third raised portion in the tire radial direction is smaller than the height of the first raised portion in the tire radial direction and the height of the second raised portion in the tire radial direction. ..

In the tire of the present invention, it is desirable that the height of the third raised portion in the tire radial direction is 50% or less of the height of the first raised portion in the tire radial direction.

In the tire of the present invention, it is desirable that the first raised portion and the second raised portion have the same height in the radial direction of the tire.

In the tire of the present invention, it is desirable that the first raised portion, the second raised portion, and the third raised portion have the same length in the tire axial direction.

In the tire of the present invention, the transverse sipe preferably includes at least one bend.

In the tire of the present invention, it is desirable that the distance between the bent portion and the third raised portion in the tire axial direction is 30% or less of the width of the first land portion in the tire axial direction.

In the tire of the present invention, it is desirable that the bent portion is located between the center position of the first land portion in the tire axial direction and the second vertical edge.

In the tire of the present invention, it is desirable that the chamfered portion expands the chamfered width from the bent portion toward both sides in the tire axial direction.

In the tire of the present invention, the transverse sipe includes a first inclined portion communicating with the first vertical edge and a second inclined portion communicating with the second vertical edge, and the first inclined portion and the second inclined portion. It is desirable that the inclined portion is inclined in the opposite direction to the tire axial direction.

In the tire of the present invention, it is desirable that the first inclined portion and the second inclined portion have different angles with respect to the tire axial direction.

In the tire of the present invention, it is desirable that the angle between the first inclined portion and the second inclined portion is an obtuse angle.

In the tire of the present invention, the direction of mounting the tread portion on the vehicle is specified, and it is desirable that the first land portion is located outside the vehicle with respect to the equator of the tire when mounted on the vehicle.

By adopting the above configuration, the present invention can suppress local wear at the sipe edge portion.

It is a development view of the tread part of the tire of one Embodiment of this invention. It is an enlarged view of the 1st land part of FIG. It is an enlarged view of the crossing sipe of FIG. FIG. 3 is a cross-sectional view taken along the line AA of FIG. FIG. 3 is a cross-sectional view taken along the line BB of FIG. It is an enlarged view of the 1st land part of another embodiment of this invention. It is sectional drawing of the cross-sectional sipe of the comparative example 1. FIG. It is sectional drawing of the cross-sectional sipe of the comparative example 2. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a developed view of a tread portion 2 of a tire 1 showing an embodiment of the present invention. The tire 1 of the present embodiment is suitably used as, for example, a pneumatic tire for a passenger car. However, the present invention is not limited to such an aspect, and may be used for a pneumatic tire for a heavy load or a non-pneumatic tire in which the inside of the tire is not filled with pressurized air.

As shown in FIG. 1, the tire 1 of the present embodiment has a tread portion 2 whose mounting direction on a vehicle is specified. The tread portion 2 has a first tread end Te1 intended to be located on the outside of the vehicle when the tire 1 is mounted on the vehicle, and a second tread end Te2 intended to be located on the inside of the vehicle when the tire 1 is mounted on the vehicle. The orientation of mounting on the vehicle is indicated by characters or symbols on the sidewall (not shown), for example. However, the tire 1 of the present invention is not limited to such an aspect, and may not be specified in the direction of mounting on the vehicle.

In the case of pneumatic tires for which various standards have been established, the first tread end Te1 and the second tread end Te2 are the most tires when a normal load is applied to the tire 1 in a normal state and the tire 1 is in contact with a flat surface at a camber angle of 0 °. It is the ground contact position on the outer side in the axial direction. The normal state is a state in which the tire is rim-assembled on the normal rim, the normal internal pressure is applied, and there is no load. In the present specification, unless otherwise specified, the dimensions and the like of each part of the tire are values measured in the normal state.

A "regular rim" is a rim defined for each tire in the standard system including the standard on which the tire is based. For example, "standard rim" for JATMA, "Design Rim" for TRA, and ETRTO. If there is, it is "Measuring Rim".

"Regular internal pressure" is the air pressure defined for each tire in the standard system including the standard on which the tire is based. For JATMA, "maximum air pressure", for TRA, the table "TIRE LOAD LIMITS AT" The maximum value described in "VARIOUS COLD INFLATION PRESSURES", or "INFLATION PRESSURE" for ETRTO.

"Regular load" is the load defined for each tire in the standard system including the standard on which the tire is based. For JATMA, "maximum load capacity", for TRA, the table "TIRE LOAD LIMITS" The maximum value described in "AT VARIOUS COLD INFLATION PRESSURES", or "LOAD CAPACITY" for ETRTO.

In the case of tires for which various standards are not defined or non-pneumatic tires, the first tread end Te1 and the second tread end Te2 are flattened at a camber angle of 0 ° by applying a standard working load to the tire in the standard use state. This is the most outer contact position in the tire axial direction when the tire touches the ground. The "standard use state" means a standard use state according to the purpose of use of the tire and a no-load state. The "standard working load" means a load of a magnitude that is normally applied in the practical use of a tire.

The tread portion 2 includes a plurality of circumferential grooves 3 continuously extending in the tire circumferential direction between the first tread end Te1 and the second tread end Te2, and a plurality of land portions 4 divided into the circumferential grooves 3. Has.

The circumferential groove 3 includes, for example, a first circumferential groove 5, a second circumferential groove 6, a third circumferential groove 7, and a fourth circumferential groove 8. In the present embodiment, the first circumferential groove 5 is provided between the first tread end Te1 and the tire equator C. The second circumferential groove 6 is provided between the first circumferential groove 5 and the tire equator C. The third circumferential groove 7 is provided between the second tread end Te and the tire equator C. The fourth circumferential groove 8 is provided between the third circumferential groove 7 and the second tread end Te2. As a result, the tire 1 of the present embodiment is configured as a so-called 5-rib tire in which the tread portion 2 has five land portions 4 divided by four circumferential grooves 3. However, the present invention is not limited to such an aspect.

The distance L1 in the tire axial direction from the tire equator C to the groove center line of the first circumferential groove 5 or the fourth circumferential groove 8 is preferably, for example, 25% to 35% of the tread width TW. The distance L2 in the tire axial direction from the tire equatorial line C to the groove center line of the second circumferential groove 6 and the third circumferential groove 7 is preferably, for example, 5% to 15% of the tread width TW. The tread width TW is the distance in the tire axial direction from the first tread end Te1 to the second tread end Te2 in the normal state.

Each circumferential groove 3 of the present embodiment extends linearly in parallel with the tire circumferential direction, for example. Each circumferential groove 3 may extend in a wavy shape, for example.

The groove width W1 of each circumferential groove 3 is preferably, for example, 3.0% to 5.0% of the tread width TW. The depth of each circumferential groove 3 is preferably 5 to 10 mm, for example, in the case of a pneumatic tire for a passenger car.

The land portion 4 includes the first land portion 11. Further, the land portion 4 of the present embodiment further includes a second land portion 12, a third land portion 13, a fourth land portion 14, and a fifth land portion 15. In the present embodiment, the first land portion 11 is divided between the first circumferential groove 5 and the second circumferential groove 6. The second land portion 12 is divided between the second circumferential groove 6 and the third circumferential groove 7. The third land portion 13 is divided between the third circumferential groove 7 and the fourth circumferential groove 8. The fourth land portion 14 is divided between the first tread end Te1 and the first circumferential groove 5. The fifth land portion 15 is divided between the second tread end Te2 and the fourth circumferential groove 8.

According to the above-described aspect, the first land portion 11 and the fourth land portion 14 are located outside the vehicle with respect to the tire equator when the vehicle is mounted. The third land portion 13 and the fifth land portion 15 are located inside the vehicle with respect to the tire equator when the vehicle is mounted. The second land portion 12 is provided on the tire equator C. However, the tire of the present invention is not limited to such an aspect.

FIG. 2 shows an enlarged view of the first land portion 11. As shown in FIG. 2, the first land portion 11 has a tread surface 11c between the first vertical edge 11a and the second vertical edge 11b extending in the tire circumferential direction. The first vertical edge 11a extends in the tire circumferential direction on the first tread end Te1 side. The second vertical edge 11b extends in the tire circumferential direction on the second tread end Te2 side. The first vertical edge 11a and the second vertical edge 11b of the present embodiment extend linearly in parallel with the tire circumferential direction. The first vertical edge 11a and the second vertical edge 11b may, for example, swing in the tire axial direction and extend in the tire circumferential direction.

The first land portion 11 includes at least one transverse sipe 20 extending from the first vertical edge 11a to the second vertical edge 11b. For ease of understanding, the transverse sipe 20 is colored in FIG. A plurality of crossing sipes 20 are provided in the tire circumferential direction in the first land portion 11 of the present embodiment.

In the present specification, a sipe is a notch formed with a small width so that at least a part of a pair of sipe walls come into contact with each other on a contact patch in a state where the normal load is applied to the tire in the normal state. means. The width of the sipe (the width of the portion where the pair of sipe walls extend parallel to each other) is, for example, 1.5 mm or less, preferably 1.0 mm or less.

FIG. 3 shows an enlarged view of the transverse sipe 20. FIG. 4 shows a cross-sectional view taken along the line AA of FIG. As shown in FIGS. 3 and 4, in the transverse sipe 20, at least one of the sipe edge portions on both sides is formed by the chamfered portion 25. The chamfered portion 25 is useful for improving the local wear resistance. The sipe edge portion means a portion of the sipe on the ground plane side including the sipe edge 26 where the sipe and the ground plane intersect. The chamfered portion 25 is formed of an inclined surface such that a corner portion formed by the main body portion 19 and the tread surface of the crossing sipe 20 is cut diagonally. The chamfered portion 25 of the present embodiment is configured as an inclined plane between the main body portion 19 and the tread surface. The chamfered portion 25 may be configured as, for example, an arc-shaped rounded shape or a rectangular-shaped recess.

As a preferred embodiment, in the transverse sipe 20 of the present embodiment, each of the sipe edge portions on both sides is formed by the chamfered portion 25. The angle of the chamfered portion 25 with respect to the tire radial direction is, for example, 30 to 60 °.

As shown in FIG. 3, the chamfered portion 25 is directed from the intermediate region in the tire axial direction of the transverse sipe 20 toward the first end 20a on the first vertical edge 11a side and the second end 20b on the second vertical edge 11b side. The chamfer width W2 is expanding. The chamfer width W2 is the distance from the sipe edge 26 to the main body side edge 27 in the tread plan view in a direction orthogonal to the length direction of the transverse sipe 20. The sipe edge 26 is an edge between the tread and the chamfered portion 25. The main body side edge 27 is an edge between the chamfered portion 25 and the main body portion 19.

FIG. 5 shows a cross-sectional view taken along the line BB of FIG. As shown in FIG. 5, the transverse sipe 20 has a first raised portion 31 having a raised bottom surface on the first end 20a side, a second raised portion 32 having a raised bottom surface on the second end 20b side, and a first raised portion. A third raised portion 33 having a raised bottom surface between the portion 31 and the second raised portion 32 is included.

By adopting the above configuration, the present invention can suppress local wear at the sipe edge portion. The reason for this is presumed to be the following mechanism.

The inventors investigated in detail the situation when the edge of the transverse sipe 20 touched down. As a result, the edge of the end portion of the transverse sipe 20 in the tire axial direction has a larger slip amount with respect to the road surface than the edge of the intermediate region in the tire axial direction of the transverse sipe 20, and local wear is likely to proceed at the end portion. Was inferred. Further, it can be inferred that the first land portion 11 provided with the crossing sipe 20 is twisted and deformed at the time of touchdown, and this twisting deformation causes further local wear of the end portion.

In the tire of the present invention, the above-mentioned configurations of the chamfered portion 25 and each raised portion can sufficiently suppress the twisting deformation of the first land portion 11, and thus reduce the amount of slippage at the end portion of the transverse sipe 20. be able to. As a result, it is considered that excellent local wear resistance is exhibited.

Hereinafter, a more detailed configuration of the present embodiment will be described. As shown in FIG. 2, the first land portion 11 of the present embodiment is provided with a plurality of transverse sipes 20 having the same shape in the tire circumferential direction. However, the present invention is not limited to such an embodiment, and in other embodiments, a plurality of transverse sipes 20 having different shapes may be provided in the tire circumferential direction. The "same shape" means a mode in which the shape can be observed to be the same when the transverse sipe 20 is observed with the normal attention of the tire user, and the dimensional error normally possessed by the rubber molded product is taken into consideration. It is acceptable.

The transverse sipe 20 includes, for example, a portion inclined with respect to the tire axial direction. Specifically, it is desirable that the transverse sipe 20 includes a portion inclined at an angle of 5 to 45 ° with respect to the tire axial direction. Such a transverse sipe 20 also provides frictional force in the tire axial direction due to its edge, which in turn helps to improve steering stability.

The transverse sipe 20 preferably includes at least one bend 28. The bent portion 28 means, for example, a mode in which the bent portion 28 is bent so as to be bent within a range of 10% or less of the length of the transverse sipe 20. The transverse sipe 20 of the present embodiment includes a bent portion 28, a first inclined portion 36 communicating with the first vertical edge 11a, and a second inclined portion 37 communicating with the second vertical edge 11b. There is. The first inclined portion 36 extends from the bent portion 28 to the first vertical edge 11a so as to be inclined with respect to the tire axial direction. The second inclined portion 37 extends from the bent portion 28 to the second vertical edge 11b so as to be inclined with respect to the tire axial direction. The first inclined portion 36 and the second inclined portion 37 are inclined in opposite directions with respect to the tire axial direction, for example. Such a crossing sipe 20 increases the rigidity of the first land portion 11 when the sipe walls come into contact with each other, and contributes to the improvement of steering stability.

It is desirable that the bent portion 28 is located, for example, between the center position of the first land portion 11 in the tire axial direction and the second vertical edge 11b. The distance L3 in the tire axial direction from the second vertical edge 11b to the bent portion 28 is preferably 15% or more, more preferably 20% or more, and preferably 35 in the width W1 in the tire axial direction of the first land portion 11. % Or less, more preferably 30% or less. As a result, the bent portion 28 having a high water film cutting effect is located closer to the tire equator C than the center position, so that the wet performance is improved.

The distance between the bent portion 28 and the third raised portion 33 (shown in FIG. 5) in the tire axial direction is, for example, 30% or less, preferably 15% or less of the width W1 in the tire axial direction of the first land portion 11. Is. As a more desirable embodiment, in the present embodiment, the third raised portion 33 is provided so as to include the bent portion 28. That is, in the present embodiment, the distance between the bent portion 28 and the third raised portion 33 is set to 0. As a result, deformation in the vicinity of the bent portion 28 is suppressed, and the local wear resistance performance is improved.

It is desirable that the first inclined portion 36 and the second inclined portion 37 have different angles with respect to the tire axial direction. It is desirable that the angle of the second inclined portion 37 with respect to the tire axial direction is larger than the angle of the first inclined portion 36 with respect to the tire axial direction. In the present embodiment, the angle of the first inclined portion 36 in the tire axial direction is 10 to 20 °. The angle of the second inclined portion 37 in the tire axial direction is 20 to 30 °. The difference between the angle of the first inclined portion 36 and the angle of the second inclined portion 37 is, for example, 15 ° or less, preferably 10 ° or less. The ground pressure is likely to be evenly applied to the edges of the first inclined portion 36 and the second inclined portion 37, which contributes to the improvement of the local wear resistance performance.

The angle θ1 between the first inclined portion 36 and the second inclined portion 37 is preferably an obtuse angle, for example. The angle θ1 of the present embodiment is, for example, 100 to 150 °, preferably 105 to 135 °. As a result, the traction performance is improved while exhibiting the above-mentioned effects.

As shown in FIG. 3, in the chamfered portion 25, the chamfered width W2 increases from the bent portion 28 toward both sides in the tire axial direction. In the present embodiment, the chamfer width W2 gradually increases from the bent portion 28 to the first end 20a. Further, the chamfer width W2 gradually increases from the bent portion 28 to the second end 20b. In a preferred embodiment, the chamfer width W2 is gradually increased at a constant rate by extending the sipe edge 26 and the main body side edge 27 in a straight line. Such a chamfered portion 25 is useful for enhancing the local wear resistance.

The chamfered portion 25 has a maximum chamfered width W2 at the first end 20a or the second end 20b. The chamfered portion 25 has a minimum chamfered width W2 at the bent portion 28. The maximum value of the chamfer width W2 is, for example, 1.0 to 1.5 mm. The minimum value of the chamfer width W2 is, for example, 0.5 to 1.0 mm. The difference between the maximum value and the minimum value of the chamfer width W2 is preferably less than 1.5 mm, for example.

As shown in FIG. 5, the first raised portion 31, the second raised portion 32, and the third raised portion 33 have the same length in the tire axial direction. As a result, the local wear resistance is further improved. In addition, "the length is the same" includes a mode in which a dimensional error normally possessed by a rubber product is allowed, and the difference in length is 5% or less of the length.

The width W3 of each raised portion in the tire axial direction is set to be smaller than, for example, the distance in the tire axial direction between each raised portion. The width W3 of each raised portion in the tire axial direction is preferably 5% or more, more preferably 10% or more, preferably 20% or less, and more preferably 15 of the width W1 in the tire axial direction of the first land portion 11. % Or less. Since each of such raised portions increases the rigidity of the first land portion 11 while suppressing a decrease in the volume of the sipe, steering stability and wet performance are improved in a well-balanced manner.

It is desirable that the third raised portion 33 is arranged on the second vertical edge 11b side of the center position of the first land portion 11 in the tire axial direction, for example. The distance L4 in the tire axial direction from the second vertical edge 11b to the end of the third raised portion 33 on the second vertical edge 11b side is, for example, the width W1 in the tire axial direction of the first land portion 11 (shown in FIG. 2). 20% to 40%, preferably 25% to 35%.

If the height h3 of the third raised portion 33 in the tire radial direction is large, the rigidity of the central portion of the transverse sipe 20 in the tire axial direction becomes excessively high, which may impair the local wear resistance. From this point of view, the height h3 of the third raised portion 33 is smaller than the height h1 of the first raised portion 31 in the tire radial direction and the height h2 of the second raised portion 32 in the tire radial direction. desirable. Specifically, the height h3 of the third raised portion 33 in the tire radial direction is 50% or less, preferably 30% to 50% of the height h1 of the first raised portion 31 in the tire radial direction. Such a third raised portion 33 can exert the above-mentioned effect while maintaining wet performance.

The height h1 of the first raised portion 31 and the height h2 of the second raised portion 32 are, for example, 50% or more, preferably 50% to 75% of the maximum depth d1 of the transverse sipe 20. .. The depth d1 of the transverse sipe 20 is, for example, 60% to 80% of the maximum depth of the circumferential groove. In a preferred embodiment, the first raised portion 31 and the second raised portion 32 have the same height in the tire radial direction. As a result, the twisting deformation of the first land portion 11 is effectively suppressed, and the local wear resistance is improved.

As shown in FIG. 1, the second land portion 12 is provided with a plurality of interrupted sipes 40 extending from the second circumferential groove 6 and interrupting within the second land portion 12. It is desirable that the length of the interrupted sipe 40 in the present embodiment in the tire axial direction is larger than the length of the first inclined portion 36 of the transverse sipe 20 provided in the first land portion 11 in the tire axial direction. Further, it is desirable that the interrupted sipe 40 is inclined in the same direction as the first inclined portion 36 with respect to the tire axial direction. The break sipe 40 provides frictional force by its edge while maintaining the rigidity of the second land portion 12. Therefore, steering stability and wet performance are improved in a well-balanced manner.

The third land portion 13 is provided with, for example, a plurality of inclined crossing sipes 41 that are inclined in one direction with respect to the tire axial direction and cross the land portion. The inclined crossing sipe 41 is inclined in the direction opposite to the first inclined portion 36 with respect to the tire axial direction, for example. The maximum angle of the inclined crossing sipe 41 with respect to the tire axial direction is larger than the maximum angle of the first inclined portion 36 with respect to the tire axial direction. This improves turning performance on wet road surfaces.

It is desirable that the inclined crossing sipe 41 has a chamfered portion similar to that of the crossing sipe 20 described above. Such an inclined crossing sipe 41 is useful for improving local wear resistance.

The first land portion 11, the second land portion 12, and the third land portion 13 are not provided with grooves and sipes except for the above-mentioned sipes. As a result, each land portion has high rigidity, and excellent steering stability is exhibited.

The fourth land portion 14 and the fifth land portion 15 are provided with a plurality of lateral sipes 42 extending from the first tread end Te1 or the second tread end Te2. Such a lateral sipe 42 is useful for increasing traction during wet driving.

FIG. 6 shows an enlarged view of the first land portion 11 of another embodiment of the present invention. In FIG. 6, the same reference numerals are given to the elements common to the above-described embodiment, and the above-described configuration can be applied. Therefore, the description of the above elements is omitted here.

As shown in FIG. 6, the first land portion 11 of this embodiment is provided with a first crossing sipe 21 and a second crossing sipe 22 having different maximum inclination angles with respect to the tire axial direction. It is desirable that the first crossing sipe 21 and the second crossing sipe 22 are alternately provided in the tire circumferential direction. As a result, the frequency band of the noise generated by each transverse sipe 20 is dispersed, and white noise can be expected, and the noise performance is improved.

The difference in inclination angle between the first crossing sipe 21 and the second crossing sipe 22 is, for example, 5 to 15 °. Such a first crossing sipe 21 and a second crossing sipe 22 are useful for enhancing local wear resistance.

The first crossing sipe 21 has substantially the same configuration as the crossing sipe 20 shown in FIG. The second crossing sipe 22 is provided with a bent portion 28 between the center position of the first land portion 11 in the tire axial direction and the first vertical edge 11a. As a result, in the second crossing sipe 22, the length of the first inclined portion 36 in the tire axial direction is smaller than the length of the second inclined portion 37 in the tire axial direction. The angle of the first inclined portion 36 of the second crossing sipe 22 with respect to the tire axial direction is, for example, 25 to 35 °. The angle of the second inclined portion 37 of the second crossing sipe 22 with respect to the tire axial direction is, for example, 15 to 25 °.

Although the tire of one embodiment of the present invention has been described in detail above, the present invention is not limited to the specific embodiment described above, and may be modified to various embodiments.

A tire of size 215 / 55R17 having the basic pattern of FIG. 1 was prototyped. As Comparative Example 1, a tire having a cross-sectional shape a having a cross-sectional shape shown in FIG. 7 was prototyped. As shown in FIG. 7, the transverse sipe a of Comparative Example 1 does not have a raised portion. As Comparative Example 2, a tire having a cross-sectional shape b having a cross-sectional shape shown in FIG. 8 was prototyped. As shown in FIG. 8, the transverse sipe b of Comparative Example 2 includes a first raised portion c and a second raised portion d, but no raised portion is provided between them. The tire pattern elements of Comparative Examples 1 and 2 are substantially the same as those shown in FIG. 1, except for the above items. Local wear resistance and steering stability of each test tire were tested.
Mounting rim: 17 x 7.0J
Tire internal pressure: 230kPa
Test vehicle: Displacement 2500cc, rear-wheel drive vehicle Tire mounting position: All wheels

<Local wear resistance>
After traveling a certain distance with the above test vehicle, the state of local wear of the sipe edge portion of the crossing sipe was visually confirmed. The result is a score in which the state of the local wear of Comparative Example 1 is 100, and the larger the value, the better the local wear resistance.

<Maneuvering stability>
The steering stability of the test vehicle when traveling on a circuit consisting of a dry road surface was evaluated by the driver's sensuality. The result is a score with the steering stability of the comparative example as 100, and the larger the value, the better the steering stability.
The test results are shown in Table 1.

As a result of the test, it was confirmed that the tire of the example exhibited excellent local wear resistance. It was also confirmed that the tires of the examples maintained steering stability.

2 Tread part 11a 1st vertical edge 11b 2nd vertical edge 20 Crossing sipe 20a 1st end 20b 2nd end 25 Chamfered part 31 1st raised part 32 2nd raised part 33 3rd raised part W2 Chamfered width

Claims (20)

A tire with a tread
The tread portion includes a first land portion having a tread surface between a first vertical edge and a second vertical edge extending in the tire circumferential direction.
The first land portion includes at least one transverse sipe extending from the first longitudinal edge to the second longitudinal edge.
In the transverse sipe, at least one of the sipe edge portions on both sides is formed by a chamfered portion.
The chamfer width of the chamfered portion increases from the intermediate region of the crossing sipe in the tire axial direction toward the first end on the first vertical edge side and the second end on the second vertical edge side.
The transverse sipe includes a first raised portion having a raised bottom surface on the first end side, a second raised portion having a raised bottom surface on the second end side, and the first raised portion and the second raised portion. Including a third ridge with a raised bottom between them,
tire. The tire according to claim 1, wherein the crossing sipe includes a portion inclined with respect to the tire axial direction. The tire according to claim 1 or 2, wherein the crossing sipe includes a portion inclined at an angle of 5 to 45 ° with respect to the tire axial direction. A plurality of the crossing sipes are provided in the first land portion.
The tire according to any one of claims 1 to 3, wherein the crossing sipe includes tires having different maximum inclination angles with respect to the tire axial direction. The tire according to claim 4, wherein the difference in the inclination angles of the transverse sipe is 5 to 15 °. The tire according to any one of claims 1 to 5, wherein the crossing sipe is a tire in which each of the sipe edge portions on both sides is formed by the chamfered portion. The tire according to any one of claims 1 to 6, wherein the maximum value of the chamfer width is 1.0 to 1.5 mm. The tire according to any one of claims 1 to 7, wherein the difference between the maximum value and the minimum value of the chamfer width is less than 1.5 mm. Any one of claims 1 to 8, wherein the height of the third raised portion in the tire radial direction is smaller than the height of the first raised portion in the tire radial direction and the height of the second raised portion in the tire radial direction. The tire described in item 1. The tire according to any one of claims 1 to 9, wherein the height of the third raised portion in the tire radial direction is 50% or less of the height of the first raised portion in the tire radial direction. The tire according to any one of claims 1 to 10, wherein the first raised portion and the second raised portion have the same height in the radial direction of the tire. The tire according to any one of claims 1 to 11, wherein the first raised portion, the second raised portion, and the third raised portion have the same length in the tire axial direction. The tire according to any one of claims 1 to 11, wherein the crossing sipe includes at least one bend. The tire according to claim 13, wherein the distance between the bent portion and the third raised portion in the tire axial direction is 30% or less of the width of the first land portion in the tire axial direction. The tire according to claim 13 or 14, wherein the bent portion is located between the center position of the first land portion in the tire axial direction and the second vertical edge. The tire according to any one of claims 13 to 15, wherein the chamfered portion has a chamfered width that increases from the bent portion toward both sides in the tire axial direction. The transverse sipe includes a first inclined portion communicating with the first vertical edge and a second inclined portion communicating with the second vertical edge.
The tire according to any one of claims 1 to 16, wherein the first inclined portion and the second inclined portion are inclined in opposite directions with respect to the tire axial direction. The tire according to claim 17, wherein the first inclined portion and the second inclined portion have different angles with respect to the tire axial direction. The tire according to claim 17 or 18, wherein the angle between the first inclined portion and the second inclined portion is an obtuse angle. The direction of mounting the tread on the vehicle is specified.
The tire according to any one of claims 1 to 19, wherein the first land portion is located outside the vehicle from the equator of the tire when the vehicle is mounted.

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