JP7394613B2 - pneumatic tires - Google Patents

Description

The present invention relates to pneumatic tires.

Patent Document 1 discloses that a tread section is partitioned by an inclined groove extending in a direction inclined from the tire equator side in the tire width direction toward the ground contact end side in the tire circumferential direction, and a circumferential groove extending in the tire circumferential direction. A pneumatic tire is disclosed, which has a land portion formed with a slanted groove and a sipe extending in a direction oblique to the circumferential groove.

JP 2017-190123 Publication

In the pneumatic tire of Patent Document 1, in the land portion, the communication portion between the sipe and the inclined groove and/or the circumferential groove is divided into an acute angle, so that the stiffness locally decreases in the acutely divided portion. occurs, and wear resistance tends to deteriorate.

The present invention suppresses deterioration of wear resistance in a pneumatic tire in which a land portion partitioned by an inclined groove and a circumferential groove is formed with sipes extending in a direction inclined to the inclined groove and/or the circumferential groove. The task is to do so.

The present invention
It is formed in the tread part, extends in the tire circumferential direction in an inclined direction from the tire equator side in the tire width direction to the ground contact edge side, and is formed at intervals in the tire circumferential direction. an inclined groove;
a plurality of circumferential grooves formed in the tread portion, extending in the tire circumferential direction and communicating between the pair of circumferentially adjacent inclined grooves;
a land section defined by the plurality of inclined grooves and the plurality of circumferential grooves;
a sipe formed in the land portion and extending in a direction inclined with respect to at least one of the inclined groove and the circumferential groove that partition the land portion;
The sipe has a sipe orthogonal part that communicates at a substantially right angle with the at least one of the inclined grooves and the circumferential groove that extend in an inclined direction ,
The sipe extends between the inclined groove and the circumferential groove, one end of the inclined groove and the circumferential groove located on the shallower groove side is configured as the orthogonal part of the sipe, and To provide a pneumatic tire, the end located at is configured as a closed end that terminates at the land portion .

According to the present invention, in a land section divided by an inclined groove and a circumferential groove, a sipe extending in a direction inclined with respect to at least one of the inclined groove and the circumferential groove that partitions the land section is arranged in a direction that is inclined with respect to at least one of the inclined groove and the circumferential groove that partition the land section. The sipe orthogonal portion communicates with the inclined groove and/or the circumferential groove at a substantially right angle. As a result, the land portion is not divided into acute angles in the portion where the sipe orthogonal portion is formed, so that a local decrease in rigidity of the land portion is suppressed. Therefore, deterioration of wear resistance in the land area is suppressed.
In addition, in the land area, the sipes are not connected at the ends that are divided by deep grooves and tend to have relatively low rigidity, and the sipes are connected to the areas divided by shallow grooves by the orthogonal parts of the sipes. There is. As a result, while suppressing an excessive decrease in rigidity at the end section divided by the deep groove, it is possible to moderately reduce the rigidity at the end section sectioned by the shallow groove, and improve the tracking ability of the land section to the ground contact surface. While ensuring this, an excessive decrease in rigidity of the land portion is suppressed.

Preferably, a plurality of the sipes are formed, and the sipe orthogonal portion is included in the sipe located closest to the stepping-in side and/or the sipe located closest to the kick-off side in the tire circumferential direction, among the plurality of sipes. It is.

According to this configuration, the sipe orthogonal portion is located at the end on the stepping side and/or the end on the kicking side, where the movement of the land portion tends to be relatively large upon contact with the ground. Therefore, the sipe orthogonal portion suppresses a decrease in rigidity at the end on the stepping-in side and/or the end on the kick-off side, so that movement of the end at the time of ground contact is effectively suppressed. As a result, deterioration of wear resistance is suppressed at the stepping-in end and/or kicking-out end of the land portion, which is prone to wear.

Preferably, the sipe orthogonal portion is included in a portion of the sipe that communicates with the circumferential groove.

According to this configuration, the sipe orthogonal part is a circumferential groove that tends to move relatively large because it receives a load in the tire circumferential direction, which corresponds to the rolling direction of the pneumatic tire when touching the ground, among the land parts. It is located in the communication section of Therefore, it is easy to effectively suppress the movement of the end portion when touching the ground, and a local decrease in rigidity of the land portion is effectively suppressed. In particular, in the land portion, since the acute angle portion and the obtuse angle portion are not lined up in the tire circumferential direction across the sipe, an increase in uneven wear on both sides of the tire circumferential direction across the sipe is suppressed.

Further, preferably, a portion of the sipe excluding a portion orthogonal to the sipe extends along a grounding shape.

According to this configuration, since the portion of the sipe excluding the orthogonal part of the sipe extends along the ground contact shape, the edge effect in the contact shape can be suitably exerted, and the orthogonal part of the sipe can prevent excessive damage at the edge of the land part. Decrease in rigidity is suppressed.

According to the present invention, in a pneumatic tire in which a land portion partitioned by an inclined groove and a circumferential groove is formed with sipes extending in a direction inclined with respect to the inclined groove and/or the circumferential groove, the wear resistance deteriorates. is suppressed.

FIG. 1 is a developed view of a tread portion of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is an enlarged view of section A in FIG. 1. A sectional view taken along the line III-III in FIG. 2. A cross-sectional view taken along the line IV-IV in FIG. 2. The figure which shows the 1st mediate block based on a modification. The figure which shows the 1st mediate block based on a further modification.

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the following description is essentially just an example, and is not intended to limit the present invention, its applications, or its uses. Further, the drawings are schematic, and the ratio of each dimension is different from the actual one.

FIG. 1 is a developed view showing a tread portion 1 of a pneumatic tire according to this embodiment. Although not shown, this pneumatic tire has a structure in which a carcass is stretched between a pair of bead cores, reinforced by a belt wrapped around the outer circumferential side of the middle part of the carcass, and a tread portion 1 is provided on the outer diameter side of the tire. .

In the following description, in FIG. 1, the left-right direction will be referred to as the tire width direction TW, the right side will be referred to as the TW1 side, and the left side will be referred to as the TW2 side. Further, in FIG. 1, the vertical direction is referred to as the tire circumferential direction TC, the upper side is referred to as the TC1 side, and the lower side is referred to as the TC2 side. Note that the pneumatic tire according to the present embodiment has a designated rotation direction, with the tire circumferential direction TC2 side being the stepping side and the tire circumferential direction TC1 side being the kicking side.

Further, FIG. 1 also shows the grounding shape GS. The contour shape of the ground contact shape GS includes a pair of width direction ground contact ends GT extending in the tire circumferential direction TC on both sides of the tire width direction TW, and a pair of circumferential direction ground contact ends GL extending in the tire width direction TW on both sides of the tire circumferential direction TC. It has The circumferential ground contact end GL extends in an arc shape with a ground contact shape GS convex in the tire circumferential direction TC at the tire equator line Ce.

Note that the ground contact shape GS in this specification refers to the maximum load at the normal internal pressure when a new (that is, unworn) pneumatic tire is assembled on a regular rim and filled with air at the regular internal pressure. This means a ground contact shape that makes contact with a flat road surface on the top surface of the tread portion 1 when a load of 90% of the capacity is applied.

A "regular rim" is a rim specified for each tire by the standard in the standard system that includes the standard on which the tire is based, for example, "standard rim" for JATMA, "Design Rim" for TRA, and rim for ETRTO. If so, it would be "Measuring Rim".

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

"Regular load" is the load specified for each tire by each standard in the standard system including the standard on which the tire is based, and in the case of JATMA it is the "maximum load capacity", and in the case of TRA it is the load specified in the table "TIRE LOAD". The maximum value listed in "LIMITS AT VARIOUS COLD INFLATION PRESSURES" is "LOAD CAPACITY" for ETRTO.

A tread pattern is formed in the tread portion 1 by a plurality of grooves. The groove portion includes a first inclined groove 11 extending obliquely from the vicinity of the tire equator line Ce toward the tire width direction TW1 side, and a second inclined groove extending obliquely from the vicinity of the tire equator line Ce toward the tire width direction TW2 side. 12 is included.

The base end of the first inclined groove 11 is located on the tire width direction TW2 side across the tire equator line Ce, and communicates with the middle of the second inclined groove 12. The first inclined groove 11 extends from the base end toward the tire circumferential direction TC1 side toward the tire width direction TW1 side while gradually increasing the width dimension. The first inclined groove 11 curves convexly toward the tire width direction TW1 side toward the tire circumferential direction TC1 side, and terminates beyond the widthwise ground contact end GT located on the tire width direction TW1 side. The first inclined groove 11 has a large inclination angle with respect to a straight line extending in the tire width direction TW on the tire equator line Ce side, and this inclination angle gradually becomes smaller toward the tire width direction TW1 side. The side end portion extends substantially along the tire width direction TW.

A plurality of first inclined grooves 11 are provided at predetermined intervals in the tire circumferential direction TC. The first inclined grooves 11 adjacent to each other in the tire circumferential direction TC are connected by a first circumferential groove 21 extending in the tire circumferential direction TC. The first circumferential groove 21 is inclined toward the tire circumferential direction TC2 side and toward the tire width direction TW1 side. The first circumferential groove 21 has a shallower groove depth than the first inclined groove 11 .

A third inclined groove 13 extends from an intermediate portion of the first circumferential groove 21 . The third inclined groove 13 divides the land portion formed between the first inclined grooves 11 adjacent in the tire circumferential direction TC into two. The end position of the third inclined groove 13 is closer to the tire equator line Ce than the end position of the first inclined groove 11.

The first inclined groove 11 and the third inclined groove 13 are connected by a second circumferential groove 22 extending in the tire circumferential direction. The second circumferential groove 22 is inclined toward the tire circumferential direction TC2 side and toward the tire width direction TW1 side. The second circumferential groove 22 is located closer to the tire width direction TW1 than the first circumferential groove 21, and has a shallower groove depth than the first and third inclined grooves 11 and 13. The second circumferential grooves 22 adjacent to each other in the tire circumferential direction TC are shifted in position in the tire width direction TW. That is, the second circumferential grooves 22 are alternately provided so as to be shifted toward the tire width direction TW1 side and the tire equator line Ce side toward the tire circumferential direction TC.

The first center block 2 is defined by two first inclined grooves 11, second inclined grooves 12, and first circumferential grooves 21 that are adjacent to each other in the tire circumferential direction TC. The first center block 2 has a rhombic shape that is longer in the tire circumferential direction TC than in the tire width direction TW. The first center blocks 2 are arranged in the tire circumferential direction TC to form a first center block row.

The first mediate block 3 is defined by the first inclined groove 11, the third inclined groove 13, the first circumferential groove 21, and the second circumferential groove 22. The first mediate block 3 has a laterally elongated shape that extends in the tire width direction TW compared to the tire circumferential direction TC. The first mediate blocks 3 are arranged in the tire circumferential direction TC to form a first mediate block row. In the first mediate block row, the shapes of the first mediate blocks 3 adjacent to each other in the tire circumferential direction TC are slightly different.

That is, since the first circumferential groove 21 is inclined in the tire width direction TW1 toward the tire circumferential direction TC2 side, the pair of first mediate blocks 3 partitioned by the first circumferential groove 21 are The positions of the inner end portions in the width direction TW are different. Furthermore, the groove width of the first circumferential groove 21 is different between the upper and lower portions with the third inclined groove 13 in between. Further, the positions of the second circumferential grooves 22 adjacent to each other in the tire circumferential direction TC are shifted from each other in the tire width direction TW.

The first shoulder block 4 is defined by the first inclined groove 11, the third inclined groove 13, and the second circumferential groove 22. The first shoulder block 4 has a laterally elongated shape that extends further in the tire width direction TW than the tire circumferential direction TC compared to the first mediate block 3. The first shoulder block 4 extends in the tire width direction TW beyond the width direction ground contact end GT. The first shoulder blocks 4 are arranged in the tire circumferential direction TC to form a first shoulder block row. As described above, since the second circumferential grooves 22 are alternately shifted in the tire width direction TW toward the tire circumferential direction TC, the positions of the end portions of the respective first shoulder blocks 4 are also different.

One block set is formed by one first center block 2, two first mediate blocks 3, and two first shoulder blocks 4 between a pair of first inclined grooves 11 adjacent to each other in the tire circumferential direction. The body is made up of

The base end of the second inclined groove 12 is located on the tire width direction TW1 side across the tire equator line Ce, and communicates with the middle of the first inclined groove 11. The second inclined groove 12 extends from the base end toward the tire circumferential direction TC1 side toward the tire width direction TW2 side while gradually increasing the width dimension. The second inclined groove 12 curves in a convex manner toward the tire width direction TW2 side toward the tire circumferential direction TC1 side, and terminates beyond the widthwise ground contact end GT located on the tire width direction TW2 side. The second inclined groove 12 has a large inclination angle with respect to a straight line extending in the tire width direction TW on the tire equator line Ce side, and this inclination angle gradually becomes smaller as it goes toward the tire width direction TW2 side. The side end portion extends substantially along the tire width direction TW.

A plurality of second inclined grooves 12 are provided at predetermined intervals (same as the first inclined grooves 11) in the tire circumferential direction TC. The second inclined grooves 12 adjacent to each other in the tire circumferential direction TC are connected by a third circumferential groove 23 extending in the tire circumferential direction TC. A fourth inclined groove 14 extends from an intermediate portion of the third circumferential groove 23 . The fourth inclined groove 14 divides the land portion formed between the second inclined grooves 12 adjacent to each other in the tire circumferential direction TC into two. The second inclined groove 12 and the fourth inclined groove 14 are connected by a fourth circumferential groove 24 extending in the tire circumferential direction TC. The third and fourth circumferential grooves 23 and 24 are inclined toward the tire circumferential direction TC2 side and toward the tire width direction TW2 side.

The second center block 5 is defined by two second inclined grooves 12, a first inclined groove 11, and a third circumferential groove 23 that are adjacent to each other in the tire circumferential direction TC. The second center blocks 5 are arranged in the tire circumferential direction TC to form a second center block row.

The second mediate block 6 is defined by the second inclined groove 12, the fourth inclined groove 14, the third circumferential groove 23, and the fourth circumferential groove 24. The second mediate blocks 6 are arranged in the tire circumferential direction TC to form a second mediate block row.

The second shoulder block 7 is defined by the second inclined groove 12, the fourth inclined groove 14, and the fourth circumferential groove 24. The second shoulder blocks 7 are arranged in the tire circumferential direction TC to form a second shoulder block row.

One block set is formed by one second center block 5, two second mediate blocks 6, and two second shoulder blocks 7 between a pair of second inclined grooves 12 adjacent to each other in the tire circumferential direction. The body is made up of

The base end of the first inclined groove 11 communicates with the middle of the second inclined groove 12 at a position on the left beyond the tire equator line Ce, and extends diagonally upward to the right in a curved state. At a position next to the tire circumferential direction TC, the base end of the second inclined groove 12 communicates with the middle of the first inclined groove 11 at a position on the right beyond the tire equator line Ce, and extends diagonally upward to the left. Extends in a curved manner. That is, the first slanted groove 11 and the second slanted groove 12 form a V-shape, and their communication positions are alternately located on either side of the tire equator line Ce in the tire circumferential direction TC.

In the tread portion 1 having the above configuration, each block has sipes formed by a plurality of cuts. The term sipe used here refers to a groove with a thickness (dimension in the direction perpendicular to the longitudinal direction of the groove) that closes the groove when the groove touches the ground.For example, the groove thickness is set to 1.5 mm or less. In this embodiment, it is set to 0.5 mm.

In FIG. 2, portion A in FIG. 1 is enlarged to show the periphery of the first center block 2 and the first mediate block 3. As shown in FIG. 2, the first mediate block 3 has a first mediate sipe 30 formed therein. A diagonal line 3L is a line connecting the corner 3a of the first mediate block 3 located on the most pressing side (tire circumferential direction TC2 side) and the corner 3b located on the most kicking side (tire circumferential direction TC1 side). A plurality of first mediate sipes 30 are formed at intervals in the direction of the diagonal line 3L.

The plurality of first mediate sipes 30 include a first sipe 31 located closest to the corner 3a, a second sipe 32 located closest to the corner 3b, and a plurality of mediates located between these. A third sipe 33 is included. The first to third sipes 31 to 33 are formed substantially perpendicular to the diagonal line 3L. Further, the first to third sipes 31 to 33 extend in a direction generally along the circumferential ground contact end GL located on the kicking side (that is, the tire circumferential direction TC1 side) of the ground contact shape GS.

Here, in this specification, the expression that the first mediate sipe 30 extends in a direction generally along the circumferential ground contact edge GL means that the first mediate sipe 30 extends in the circumferential ground contact position at the same tire width direction TW position. This means that it extends in substantially the same direction as the end GL. That is, the first mediate sipe 30 is tilted in the same direction as the tire circumferential direction TC1 toward the tire width direction TW1 where the circumferential ground contact edge GL extends at the tire width direction position TW where the sipe is formed. It extends at an incline.

This makes it easy to effectively exert the edge effect by the first to third sipes 31 to 33 in the kicking side region of the ground contact shape. Moreover, by forming the plurality of first mediate sipes 30 in the diagonal line 3L direction along the tire circumferential direction TC, the first mediate sipes 30 are arranged along a direction closer to the tire width direction TW rather than the tire circumferential direction TC. It is easy to increase the number of holes formed while forming them so as to extend in the same direction.

The first sipe 31 extends between the edge of the first mediate block 3 defined by the first inclined groove 11 and the edge defined by the first circumferential groove 21 in a brace-like manner. It extends in an inclined direction. Specifically, the first sipe 31 includes a sipe line portion 31a that is substantially orthogonal to the diagonal line 3L and extends in a straight or curved shape, and a linear portion that is bent from the sipe line portion 31a toward the tire width direction TW2 side. It is configured as a bent sipe, and has a sipe orthogonal section 31b that extends to the first circumferential groove 21 and communicates with the first circumferential groove 21 at a substantially right angle. The sipe line portion 31a terminates at a position spaced apart from the first inclined groove 11, and the first sipe 31 is configured as a closed sipe.

In this specification, the expression that the first mediate sipe 30 is substantially perpendicular to the diagonal line 3L means that the angular difference between the respective extending directions of the two at the intersection is 70° or more and 110° or less. It means. Furthermore, in this specification, the expression that the sipe orthogonal portion 31b communicates with the first circumferential groove 21 at a substantially right angle means that the angular difference between the extending directions of both is 70° or more and 110° or less. It means.

The first sipe 31 is formed at least a length L1 away from the corner 3a. The length L1 is, for example, 4 mm. If the length L1 is less than 4 mm, the portion of the first mediate block 3 that is partitioned by the first sipe 31 toward the corner portion 3a will become excessively small, and the rigidity of this portion will decrease excessively. Abrasion resistance tends to deteriorate. Further, the sipe orthogonal portion 31b is formed to have at least a length L2. The length L2 is, for example, 1.5 mm. If the length L2 is less than 1.5 mm, the portion partitioned by the sipe orthogonal portion 31b toward the corner portion 3a will have a shape close to an acute angle, and the rigidity of the portion will likely decrease excessively.

FIG. 3 is a sectional view taken along line III-III in FIG. 2, and shows a sectional view taken along the first sipe 31 of the first mediate block 3. As shown in FIG. 3, the first sipe 31 communicates with the relatively shallow first circumferential groove 21 of the first inclined groove 11 and the first circumferential groove 21 through a sipe orthogonal portion 31b. and is configured not to communicate with the relatively deep first inclined groove 11. The first sipe 31 is configured such that the groove depth gradually decreases toward the first circumferential groove 21 at the sipe orthogonal portion 31b.

The second sipe 32 is configured similarly to the first sipe 31. As shown in FIG. 2, the second sipe 32 is located between the edge of the first mediate block 3 defined by the first inclined groove 11 and the edge defined by the second circumferential groove 22. , and extends in a diagonal direction in the form of a brace with respect to these. Specifically, the second sipe 32 includes a sipe line portion 32a that extends linearly or curved in a direction substantially perpendicular to the diagonal line 3L, and a sipe line portion 32a that is bent from the sipe line portion 32a and extends linearly toward the tire width direction TW1 side. It has a sipe orthogonal section 32b that extends to the second circumferential groove 22 and communicates with the second circumferential groove 22 at a substantially right angle. The sipe line portion 32a terminates at a position spaced apart from the first inclined groove 11, and the second sipe 32 is configured as a closed sipe.

Although not shown, the second sipe 32 communicates with the relatively shallow second circumferential groove 22 of the first inclined groove 11 and the second circumferential groove 22 through a sipe orthogonal portion 32b. , it is configured not to communicate with the relatively deep first inclined groove 11. Further, the second sipe 32 is configured such that the groove depth gradually decreases toward the second circumferential groove 22 at the sipe orthogonal portion 32b.

Each of the plurality of third sipes 33 has a sipe waveform portion having an amplitude in the diagonal line 3L direction at the center in the longitudinal direction. The plurality of third sipes 33 are configured such that the one located at the center in the direction of the diagonal line 3L has a long sipe waveform part, and the length of the sipe waveform part gradually decreases toward both sides of the diagonal line 3L. There is.

FIG. 4 is a sectional view taken along the line IV--IV in FIG. 2, and shows a sectional view taken along the third sipe 33 of the first mediate block 3. As shown in FIG. 4 , the third sipe 33 communicates with both the first inclined groove 11 and the first circumferential groove 21 . The third sipe 33 has a depth at both ends (i.e., a communicating portion to the first inclined groove 11, the first circumferential groove 21, and the second circumferential groove 22) compared to the depth at the central portion in the longitudinal direction. The groove depth is shallow. As a result, since the depth of the third sipe 33 is shallow at the end of the first mediate block where rigidity is relatively likely to decrease, excessive decrease in rigidity is suppressed.

As shown in FIG. 2, the first center block 2 has a first center sipe 40 formed therein. Like the first mediate sipe 30, the first center sipe 40 connects the corner 4a of the first center block 2 located closest to the stepping-in side and the corner 4b located closest to the kick-off side. A plurality of them are formed at intervals in the direction of the diagonal line 4L, and each is substantially orthogonal to the diagonal line 4L.

The first center sipe 40 includes a first sipe 41 located closest to the corner 4a, a second sipe 42 located closest to the corner 4b, and a plurality of third sipes located between these. Sipe 43 is included.

Since the diagonal line 4L extends substantially along the tire circumferential direction TC, the first center sipe 40 substantially perpendicular thereto extends substantially along the tire width direction TW. Among the plurality of first center sipes 40, the first sipe 41 located closest to the stepping-in side and the second sipe 42 located closest to the kick-off side are each configured as a bent sipe. The first sipe 41 is a sipe so as to communicate with the second inclined groove 12 extending more along the tire circumferential direction TC among the first inclined groove 11 and the second inclined groove 12 that partition the corner 4a. An orthogonal portion 41b is located there.

The second sipe 42 has a sipe orthogonal portion 42b so as to communicate with the first circumferential groove 21 having a shallow groove depth among the first inclined groove 11 and the first circumferential groove 21 that partition the corner 4b. positioned.

The third sipe 43 has a sipe waveform portion having an amplitude in the diagonal line 4L direction at the center in the longitudinal direction. The plurality of third sipes 43 are configured such that the one located at the center in the direction of the diagonal line 4L has a long sipe waveform part, and the length of the sipe waveform part gradually decreases toward both sides of the diagonal line 4L. There is.

As shown in FIG. 1, the first shoulder block 4 has a first shoulder sipe 50 formed therein. The first shoulder sipes 50 are formed substantially parallel to the first inclined groove 11 and the third inclined groove 13, and are formed in plural at intervals in the tire circumferential direction. The first shoulder sipe 50 alternately includes sipe line portions 51 extending linearly or curved along the longitudinal direction and sipe waveform portions 52 having an amplitude in the tire circumferential direction.

Similarly, the second center block 5, second mediate block 6, and second shoulder block 7 are also formed with a second center sipe 60, a second mediate sipe 70, and a second shoulder sipe 80, respectively. The configuration of the second center sipe 60, second mediate sipe 70, and second shoulder sipe 80 is such that the first center sipe 40, first mediate sipe 30, and first shoulder sipe 50 are aligned with respect to the tire equator line Ce. This is a structure in which the structure is substantially line symmetrical and shifted by a predetermined pitch in the circumferential direction of the tire, and a detailed description thereof will be omitted.

According to the pneumatic tire described above, the following effects can be obtained. Note that although the following effects will be explained with respect to the first mediate block 3, they can be similarly obtained in the first center block 2, the second center block 5, and the second mediate block 6.

(1) A plurality of first mediate sipes formed in the first mediate block 3 partitioned by the first inclined groove 11 and the first and second circumferential grooves 21 and 22 so as to be substantially perpendicular to the diagonal line 3L. 30, first and second sipes 31 and 32 communicate with the first and second circumferential grooves 21 and 22 at substantially right angles through sipe orthogonal portions 31b and 32b, respectively.

As a result, the first mediate block 3 is not partitioned into an acute angle in the portion where the sipe orthogonal portions 31b and 32b are formed, so that a local decrease in rigidity in the portion is suppressed. Therefore, deterioration of the wear resistance in the first mediate block 3 is suppressed.

(2) The sipe orthogonal portions 31b and 32b are located at the stepping-in end and/or the kicking-out end of the first mediate block 3, where the movement tends to be relatively large during ground contact. . Therefore, since the sipe orthogonal portions 31b and 32b suppress a decrease in rigidity at the stepping-in end and/or the kicking-out end, movement of the end at the time of ground contact is effectively suppressed. As a result, deterioration of wear resistance is suppressed at the stepping-in end and/or kicking-out end of the land portion, which is prone to wear.

(3) Among the first mediate blocks 3, the sipe orthogonal parts 31b and 32b receive a load in the tire circumferential direction TC, which corresponds to the rolling direction of the pneumatic tire when it touches the ground, so their movements are relatively large. It is located in a portion that communicates easily with the first and second circumferential grooves 21 and 22.

Therefore, it is easy to effectively suppress the movement of the end portion of the first mediate block 3 in the tire width direction TW at the time of contact with the ground, and a local decrease in rigidity of the first mediate block 3 is effectively suppressed. In particular, the first mediate block 3 has an acute angle portion and an obtuse angle portion that are not lined up in the tire circumferential direction with the first and second sipes 31 and 32 in between. Increase in uneven wear on both sides of the tire circumferential direction TC is suppressed.

(4) The first and second sipes 31 and 32 communicate with each other at the ends of the first mediate block 3 that are divided by the relatively deep first inclined grooves 11 and tend to have relatively low rigidity. The sipe orthogonal portions 31b and 32b of the first and second sipes 31 and 32 are located in the portions partitioned by the relatively shallow first and second circumferential grooves 21 and 22.

As a result, while suppressing an excessive decrease in rigidity at the ends of the first mediate block 3 that are partitioned by relatively deep grooves, the rigidity at the ends that are partitioned by relatively shallow grooves is moderately reduced. This allows the first mediate block 3 to follow the contact surface while ensuring that excessive reduction in rigidity is suppressed.

(5) The sipe line portions 31a, 32a of the first and second sipes 31, 32, and the third sipe 33 extend substantially along the circumferential ground end GL in the ground contact shape GS, so the edges in the ground contact shape GS The sipe orthogonal portions 31b and 32b suppress an excessive decrease in rigidity at the edge of the first mediate block 3 while suitably exhibiting the effect.

In the above embodiment, the first and second sipes 31 and 32 of the first mediate block 3 are configured as bent sipes, but as shown in FIG. A sipe orthogonal portion 33b may be formed in a portion communicating with the directional grooves 21 and 22.

Furthermore, in the first mediate sipe 30, not only the first and second circumferential grooves 21 and 22, but also the entire portion communicating with the first inclined groove 11, as shown in FIG. 33b may also be formed. This further suppresses a decrease in rigidity at the end of the first mediate block 3 due to the formation of the first mediate sipe 30.

However, if the sipe orthogonal portions are formed in all the communication portions, the portion of the grounding shape GS along the circumferential grounding end GL is reduced, so the edge effect is reduced. Therefore, it is more effective to form the sipe orthogonal portions only at the stepping-in end and the kicking-out end of the first mediate block 3, which are easy to move due to input from the road surface.

Further, in the above embodiment, the first and second sipes 31 and 32 were configured to have the sipe line portions 31a and 32a and the orthogonal sipe portions 31b and 32b, but the sipe line portions 31a and 32a were configured to have the sipe waveform portions. may be replaced with

Further, in the embodiment described above, the first and second sipes 31 and 32 extend in a direction inclined in a brace manner with respect to both the first inclined groove 11 and the first or second circumferential grooves 21 and 22. However, it suffices to extend so as to be inclined with respect to at least one of these. In this case, the sipe orthogonal portion may be formed in a communicating portion with the at least one inclined groove.

Further, in the above embodiment, the case where sipes are formed in a block pattern is explained as an example, but the present invention may also be applied to a case where sipes are formed in a rib pattern. That is, when forming a sipe extending in a direction oblique to the main groove that partitions the rib, a sipe orthogonal part is formed in the part communicating with the main groove so as to be orthogonal to the main groove. Good too. In particular, when the main groove is provided in a zigzag shape and sipes are formed at the corners defined by the main groove, it is possible to prevent the corners from being divided into small areas with acute angles by the sipes. Decrease in rigidity due to formation is suppressed.

Note that the present invention is not limited to the configuration described in the above embodiments, and various changes are possible.

1 Tread portion 2 First center block 3 First mediate block 3L Diagonal line 4 First shoulder block 5 Second center block 6 Second mediate block 7 Second shoulder block 11 to 14 First to fourth inclined grooves 21 to 24 First to fourth circumferential grooves 30 First mediate sipes 31 to 33 First to third sipes 31a, 32a Sipe line portions 31b, 32b Sipe orthogonal portions 40 First center sipe 50 First shoulder sipe 60 Second center sipe 70 Second mediate sipe 80 Second shoulder sipe

Claims (4)

The tread is formed in the tread portion, extends in the tire circumferential direction in an inclined direction from the tire equator line side to the ground contact edge side in the tire width direction, and is formed at intervals in the tire circumferential direction. an inclined groove;
a plurality of circumferential grooves formed in the tread portion, extending in the tire circumferential direction and communicating between the pair of circumferentially adjacent inclined grooves;
a land portion defined by the plurality of inclined grooves and the plurality of circumferential grooves;
and a sipe formed in the land portion and extending in a direction inclined with respect to at least one of the inclined groove and the circumferential groove that constitute the land portion,
The sipe has a sipe orthogonal portion that communicates at a substantially right angle with the at least one of the inclined grooves and the circumferential groove that extend in an inclined direction ,
The sipe extends between the inclined groove and the circumferential groove, one end of the inclined groove and the circumferential groove located on the shallower groove side is configured as the orthogonal part of the sipe, and A pneumatic tire , wherein the end located at is configured as a closed end that terminates at the land portion . A plurality of sipes are formed,
The sipe orthogonal portion is included in the sipe located closest to the stepping-in side and/or the sipe located closest to the kick-off side in the tire circumferential direction, among the plurality of sipes.
The pneumatic tire according to claim 1. The sipe orthogonal portion is included in a portion of the sipe that communicates with the circumferential groove,
The pneumatic tire according to claim 1 or 2. A portion of the sipe excluding the orthogonal portion of the sipe extends along a grounding shape.
The pneumatic tire according to any one of claims 1 to 3 .

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