JP6828512B2 - tire - Google Patents

Description

The present invention relates to a tire having excellent uneven wear resistance.

For example, Patent Document 1 below proposes a tire having a tread portion in which the direction of mounting on a vehicle is specified. This tire has an outer shoulder land portion located on the outside of the vehicle when mounted on the vehicle and an inner shoulder land portion located on the inside of the vehicle when mounted on the vehicle. The land portion of the outer shoulder is provided with a plurality of lateral shoulder grooves extending inward in the tire axial direction from the tread end. The inner shoulder land portion is provided with a plurality of inner shoulder lateral grooves extending inward in the tire axial direction from the tread end. These shoulder lateral grooves drain water in the tread to the tread end side, improving wet performance.

In the above tire, the groove edge of each outer shoulder lateral groove intersects the tread end at the first intersection and the second intersection. The groove edge of each inner shoulder lateral groove intersects the tread end at the third and fourth intersections.

Generally, when the tires are running, the land portion slides relatively large with respect to the road surface at the moment when the positions of the first to fourth intersections of the lateral grooves touch the road surface and at the moment when the tires move away from the road surface. Such land slippage leads to land wear. In particular, when the first intersection or the second intersection touches the road surface at the same time as the third or fourth intersection or separates from the road surface, the inner and outer shoulder land parts slide with respect to the road surface at the same time, and the land part during tire running. The amount of slippage increases. The repeated occurrence of such slippage tends to promote uneven wear (for example, heel-and-toe wear) in which the vicinity of the groove edge of the lateral groove of the tread portion is worn at an early stage.

Japanese Unexamined Patent Publication No. 2016-15601

The present invention has been devised in view of the above problems, and a main object of the present invention is to provide a tire having excellent uneven wear resistance while maintaining wet performance.

The present invention is a tire having a tread portion whose mounting direction on a vehicle is specified, and the tread portion includes an outer shoulder land portion including an outer tread end located on the outside of the vehicle when mounted on the vehicle, and a land portion on the outer shoulder when mounted on the vehicle. The outer shoulder land portion includes an inner shoulder land portion including an inner tread end located inside the vehicle, and the outer shoulder land portion is provided with a plurality of outer shoulder lateral grooves extending inward in the tire axial direction from at least the outer tread end. A plurality of inner shoulder lateral grooves extending inward in the tire axial direction from at least the inner tread end are provided on the land portion, and each outer shoulder lateral groove is a first groove located in a first direction which is one side in the tire circumferential direction. It has an edge and a second groove edge located in a second direction opposite to the first direction in the tire circumferential direction, and the first groove edge and the second groove edge are each the outer tread end. At the first intersection and the second intersection, each inner shoulder lateral groove has a third groove edge located in the first direction in the tire circumferential direction and a fourth groove edge located in the second direction in the tire peripheral direction. The third groove edge and the fourth groove edge intersect the inner tread end at the third intersection and the fourth intersection, respectively, and the first intersection and the second intersection are the third intersections, respectively. And the fourth intersection is provided at a different position in the tire circumferential direction.

The tire of the present invention is a group of first to fourth intersections located closest to each other in the tire circumferential direction, and the first intersection, the second intersection, the third intersection and the first intersection toward the second direction. It is desirable that the tires are arranged in the order of the four intersections in the tire circumferential direction.

In the tire of the present invention, the distance L1 in the tire circumferential direction between the second intersection and the third intersection is the groove width at the outer tread end of the outer shoulder lateral groove and the inner tread of the inner shoulder lateral groove. It is desirable that it is smaller than the groove width at the end.

In the tire of the present invention, the distance L1 is preferably 0.2 to 1.0 mm.

In the tire of the present invention, it is desirable that the outer shoulder lateral groove completely crosses the outer shoulder land portion.

In the tire of the present invention, it is desirable that the inner end of the inner shoulder lateral groove in the tire axial direction is located in the inner shoulder land portion.

In the tire of the present invention, the outer shoulder lateral groove and the inner shoulder lateral groove each have an angle of less than 10 ° with respect to the tire axial direction, and the maximum angle of the inner shoulder lateral groove with respect to the tire axial direction is the outer side. It is desirable that the shoulder lateral groove is smaller than the maximum angle with respect to the tire axial direction.

In the tire of the present invention, the outer shoulder sipe is provided on the outer shoulder land portion, the inner shoulder sipe is provided on the inner shoulder land portion, and the outer shoulder sipe and the inner shoulder sipe are shallow, respectively. The outer shoulder sipe has a bottom portion and a deep bottom portion having a depth larger than that of the shallow bottom portion, the shallow bottom portion is provided inside the deep bottom portion in the tire axial direction, and the inner shoulder sipe is the shallow portion. It is desirable that the bottom portion is provided on the outer side of the deep bottom portion in the tire axial direction.

Each outer shoulder lateral groove provided on the land portion of the outer shoulder of the tire of the present invention has a first groove edge located in the first direction, which is one side in the tire circumferential direction, and is opposite to the first direction in the tire circumferential direction. It has a second groove edge located in the second direction on the side. The first groove edge and the second groove edge intersect the outer tread end at the first intersection and the second intersection, respectively.

Each inner shoulder lateral groove provided on the land portion of the inner shoulder has a third groove edge located in the first direction in the tire circumferential direction and a fourth groove edge located in the second direction in the tire circumferential direction. The third groove edge and the fourth groove edge intersect the inner tread end at the third intersection and the fourth intersection, respectively.

In the tire of the present invention, the first intersection and the second intersection are provided at different positions in the tire circumferential direction from the third intersection and the fourth intersection, respectively. Therefore, according to the present invention, since each intersection touches the ground at different timings when the tire is running, it is possible to prevent the inner and outer shoulder land portions from slipping on the road surface at the same time. Therefore, according to the tire of the present invention, it is possible to reduce the amount of slippage of the shoulder land portions on both sides during tire running while maintaining the wet performance due to the shoulder lateral groove, and by extension, to provide excellent uneven wear resistance. ..

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 outer shoulder land part of FIG. It is an enlarged view of the inner shoulder land part of FIG. It is a partially enlarged view of the outer shoulder lateral groove and the inner shoulder lateral groove of FIG. (A) is a sectional view taken along line AA of FIG. 3, (b) is a sectional view taken along line BB of FIG. 2, and (c) is a sectional view taken along line CC of FIG. .. It is an enlarged view of the outer middle land part of FIG. It is a partially enlarged view of the outer shoulder lateral groove and the outer middle lateral groove of FIG. (A) is a sectional view taken along line DD of FIG. 6, and FIG. 6B is a sectional view taken along line EE of FIG. It is an enlarged view of the inner middle land part and the crown land part of FIG. FIG. 9A is a sectional view taken along line FF of FIG. 9, FIG. 9B is a sectional view taken along line GG of FIG. 9, and FIG. 9C is a sectional view taken along line HF of FIG. , (D) are sectional views taken along line I-I of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a developed view of the tread portion 2 of the tire 1 of the present embodiment. The tire 1 of the present embodiment can be used for various tires such as pneumatic tires for passenger cars and heavy loads, and non-pneumatic tires in which pressurized air is not filled inside the tires. The tire 1 of the present embodiment is suitably used as, for example, a pneumatic tire for a passenger car.

As shown in FIG. 1, the tire 1 of the present embodiment has, for example, a tread portion 2 whose mounting direction on a vehicle is specified. The tread portion 2 has an outer tread end To located on the outside of the vehicle when the tire 1 is mounted on the vehicle, and an inner tread end Ti located on the inside of the vehicle when the tire 1 is mounted on the vehicle. The direction of mounting on the vehicle is indicated by characters or symbols on the sidewall (not shown), for example.

In the case of a pneumatic tire, the tread ends To and Ti are the outermost ground contact positions in the tire axial direction when a normal load is applied to the tire 1 in a normal state and the tire 1 is grounded on a flat surface at a camber angle of 0 °. 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 JATTA, "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 JATTA, "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.

The tread portion 2 is provided with a plurality of main grooves that extend continuously in the tire circumferential direction. The plurality of main grooves include, for example, an outer shoulder main groove 3, an inner shoulder main groove 4, an outer crown main groove 5, and an inner crown main groove 6. Each of the main grooves 3 to 6 of the present embodiment extends linearly, for example, but is not limited to such an embodiment, and may extend in a zigzag shape, for example.

The outer shoulder main groove 3 is provided, for example, on the outermost tread end To side of the plurality of main grooves. The inner shoulder main groove 4 is provided, for example, on the innermost tread end Ti side of the plurality of main grooves. The outer crown main groove 5 is provided, for example, between the outer shoulder main groove 3 and the tire equator C. The inner crown main groove 6 is provided, for example, between the inner shoulder main groove 4 and the tire equator C.

For the outer shoulder main groove 3 and the inner shoulder main groove 4, for example, it is desirable that the distance L2 from the tire equator C to the groove center line is 0.25 to 0.35 times the tread width TW. For the outer crown main groove 5 and the inner crown main groove 6, for example, it is desirable that the distance L3 from the tire equator C to the groove center line is 0.05 to 0.15 times the tread width TW. The tread width TW is the distance in the tire axial direction from the outer tread end To to the inner tread end Ti in the normal state.

It is desirable that the inner shoulder main groove 4, the outer crown main groove 5, and the inner crown main groove 6 have, for example, groove widths W1a, W1b, and W1c that are 5 to 8% of the tread width TW. It is desirable that the outer shoulder main groove 3 has, for example, a groove width W1d smaller than the groove widths W1a to W1c. It is desirable that the groove width W1d of the outer shoulder main groove 3 is, for example, 0.40 to 0.50 times the groove width W1a of the inner shoulder main groove 4. As a result, wet performance and steering stability are well-balanced.

In the case of passenger car tires, it is desirable that each of the main grooves 3 to 6 has a depth of, for example, about 5 to 10 mm. Each of such main grooves 3 to 6 can improve wet performance and steering stability in a well-balanced manner. However, the dimensions of the main grooves 3 to 6 are not limited to such a range.

By providing the above-mentioned main grooves 3 to 6, the tread portion 2 has an outer shoulder land portion 10, an inner shoulder land portion 11, an outer middle land portion 12, an inner middle land portion 13, and a crown land portion. 14 is classified. The outer shoulder land portion 10 is divided into the outer side of the outer shoulder main groove 3 in the tire axial direction, and includes the outer tread end To. The inner shoulder land portion 11 is divided into the outer side of the inner shoulder main groove 4 in the tire axial direction, and includes the inner tread end Ti. The outer middle land portion 12 is divided between the outer shoulder main groove 3 and the outer crown main groove 5. The inner middle land portion 13 is divided between the inner shoulder main groove 4 and the inner crown main groove 6. The crown land portion 14 is divided between the outer crown main groove 5 and the inner crown main groove 6.

FIG. 2 shows an enlarged view of the outer shoulder land portion 10. As shown in FIG. 2, the outer shoulder land portion 10 is provided with a plurality of outer shoulder lateral grooves 16.

Each outer shoulder lateral groove 16 extends inward in the tire axial direction from at least the outer tread end To. In a preferred embodiment, the outer shoulder lateral groove 16 completely crosses the outer shoulder land portion 10.

Each outer shoulder lateral groove 16 has a first groove edge 16a and a second groove edge 16b. The first groove edge 16a is located in the first direction, which is one side in the tire circumferential direction. The second groove edge 16b is located in the second direction opposite to the first direction in the tire circumferential direction. The first groove edge 16a and the second groove edge 16b intersect the outer tread end To at the first intersection 21 and the second intersection 22, respectively.

FIG. 3 shows an enlarged view of the inner shoulder land portion 11. As shown in FIG. 3, the inner shoulder land portion 11 is provided with a plurality of inner shoulder lateral grooves 17.

Each inner shoulder lateral groove 17 extends inward in the tire axial direction from at least the inner tread end Ti. In a preferred embodiment, the inner end 17i of the inner shoulder lateral groove 17 in the tire axial direction is located within the inner shoulder land portion 11.

Each inner shoulder lateral groove 17 has a third groove edge 17a and a fourth groove edge 17b. The third groove edge 17a is located in the first direction in the tire circumferential direction. The fourth groove edge 17b is located in the second direction in the tire circumferential direction. The third groove edge 17a and the fourth groove edge 17b intersect the inner tread end Ti at the third intersection 23 and the fourth intersection 24, respectively.

FIG. 4 shows a partially enlarged view of the outer shoulder lateral groove 16 and the inner shoulder lateral groove 17. As shown in FIG. 4, the first intersection 21 and the second intersection 22 are provided at different positions in the tire circumferential direction from the third intersection 23 and the fourth intersection 24, respectively. Therefore, according to the present invention, since the intersections 21 to 24 touch the ground at different timings when the tires are running, it is possible to prevent the inner and outer shoulder land portions 10 and 11 from slipping on the road surface at the same time. Therefore, according to the tire 1 of the present invention, the slip amount of the shoulder land portions 10 and 11 on both sides during tire running is reduced while maintaining the wet performance due to the shoulder lateral grooves 16 and 17, and by extension, excellent uneven wear resistance is achieved. Performance can be provided.

In a preferred embodiment, in the group of the first to fourth intersections 21 to 24 located closest to each other in the tire circumferential direction, the first intersection 21, the second intersection 22, the third intersection 23 and the fourth intersection toward the second direction. They are arranged in the tire circumferential direction in the order of intersection 24. Such an arrangement of the first to fourth intersections 21 to 24 can more reliably exert the above-mentioned effect. However, the present invention is not limited to such an aspect, and for example, the third intersection 23 may be located between the first intersection 21 and the second intersection 22 in the tire circumferential direction.

The distance L1 in the tire circumferential direction between the second intersection 22 and the third intersection 23 is, for example, the groove width W2 (shown in FIG. 2) at the outer tread end To of the outer shoulder lateral groove 16 and the inner shoulder lateral groove 17. It is desirable that it is smaller than the groove width W3 (shown in FIG. 3) at the inner tread end Ti. If the distance L1 is larger than these, the vibration of the tire may increase.

More specifically, the distance L1 is preferably 0.2 mm or more, more preferably 0.4 mm or more, preferably 1.0 mm or less, and more preferably 0.8 mm or less. As a result, the shoulder lateral grooves 16 and 17 can work together to exhibit excellent drainage while exhibiting excellent uneven wear resistance.

As shown in FIGS. 2 and 3, the groove width W2 of the outer shoulder lateral groove 16 and the groove width W3 of the inner shoulder lateral groove 17 are, for example, 0 of the groove width W1d (shown in FIG. 1) of the outer shoulder main groove 3. It is desirable that it is 0.8 to 1.2 times. Further, the ratio W2 / W3 of the groove width W2 to the groove width W3 is preferably 0.8 to 1.2, for example. Such an outer shoulder lateral groove 16 and an inner shoulder lateral groove 17 are useful for enhancing wet performance and uneven wear resistance in a well-balanced manner.

It is desirable that the outer shoulder lateral groove 16 and the inner shoulder lateral groove 17 each have an angle of preferably less than 20 °, more preferably less than 10 ° with respect to the tire axial direction, for example. In the present specification, the angle of the groove with respect to the tire axial direction means the angle of the center line of the groove with respect to the tire axial direction. Such outer shoulder lateral grooves 16 and inner shoulder lateral grooves 17 can create a flow of water in the entire groove during wet running in combination with the arrangement of the first to fourth intersections 21 to 24 described above, and drainage. You can improve your sex.

In a preferred embodiment, the outer shoulder lateral groove 16 and the inner shoulder lateral groove 17 gradually increase in angle with respect to the tire axial direction toward the tire equator C side. In a more desirable embodiment, the maximum angle θ2 of the inner shoulder lateral groove 17 with respect to the tire axial direction is smaller than the maximum angle θ1 of the outer shoulder lateral groove 16 with respect to the tire axial direction. As a result, the wear resistance of the inner shoulder land portion 11 is enhanced.

It is desirable that the inner shoulder lateral groove 17 has, for example, a length L4 in the tire axial direction that is 0.75 to 0.85 times the width W4 in the tire axial direction of the inner shoulder land portion 11. Such an inner shoulder lateral groove 17 can maintain the rigidity of the inner shoulder land portion 11 inside in the tire axial direction. Therefore, wet performance and steering stability are well-balanced.

FIG. 5A shows a sectional view taken along line AA of the inner shoulder lateral groove 17 of FIG. As shown in FIG. 5A, the inner shoulder lateral groove 17 has an inclined bottom surface 25 having an angle θ3 with respect to a normal line passing through the tread at an angle θ3 of 40 to 50 °, for example, at the inner end portion in the tire axial direction. Is desirable. As a result, the rigidity of the inner shoulder land portion 11 is prevented from being locally changed, and excellent uneven wear resistance can be obtained.

As shown in FIG. 2, the outer shoulder land portion 10 is provided with a plurality of outer shoulder sipes 18. In the present embodiment, the outer shoulder sipe 18 and the outer shoulder lateral groove 16 are alternately provided in the tire circumferential direction. As used herein, the term "sipe" means a notch having a width of less than 3 mm.

The outer shoulder sipe 18 of the present embodiment completely crosses, for example, the outer shoulder land portion 10. It is desirable that the outer shoulder sipe 18 is inclined in the same direction as the outer shoulder lateral groove 16 with respect to the tire axial direction, for example. In a preferred embodiment, the outer shoulder sipes 18 are arranged, for example, at an angle θ4 of 5-10 ° with respect to the tire axial direction.

FIG. 5B is provided with a sectional view taken along line BB of the outer shoulder sipe 18 of FIG. As shown in FIG. 5B, the outer shoulder sipe 18 has, for example, a shallow bottom 26 and a deep bottom 27 having a depth greater than the shallow 26. The shallow bottom portion 26 has, for example, a depth d2 that is 0.10 to 0.20 times the depth d1 of the outer shoulder main groove 3. The deep bottom portion 27 has, for example, a depth d3 that is 0.55 to 0.65 times the depth d1 of the outer shoulder main groove 3. In the outer shoulder sipe 18 of the present embodiment, for example, the shallow bottom portion 26 is provided inside the deep bottom portion 27 in the tire axial direction. Such an outer shoulder sipe 18 helps to suppress wear on the inner side of the outer shoulder land portion 10 in the tire axial direction.

As a more desirable embodiment, it is desirable that the outer shoulder sipe 18 of the present embodiment is provided with a shallow bottom portion 28 having a depth smaller than that of the deep bottom portion 27 even outside the outer tread end To. Such an outer shoulder sipe 18 can suppress uneven wear near the outer tread end To while improving wandering performance.

As shown in FIG. 3, the inner shoulder land portion 11 is provided with a plurality of inner shoulder sipes 19. In the present embodiment, the inner shoulder sipe 19 and the inner shoulder lateral groove 17 are alternately provided in the tire circumferential direction.

The inner shoulder sipe 19 of the present embodiment completely crosses, for example, the inner shoulder land portion 11. It is desirable that the inner shoulder sipe 19 is inclined in the same direction as the inner shoulder lateral groove 17, for example. In a preferred embodiment, the inner shoulder sipe 19 is preferably tilted at an angle θ5 of, for example, 5-10 ° with respect to the tire axial direction.

FIG. 5 (c) is provided with a sectional view taken along line CC of the inner shoulder sipe 19. As shown in FIG. 5 (c), the inner shoulder sipe 19 has, for example, a shallow bottom portion 31 and a deep bottom portion 32 having a depth larger than that of the shallow bottom portion 31. It is desirable that the shallow bottom portion 31 has, for example, a depth d5 that is 0.10 to 0.20 times the depth d4 of the inner shoulder main groove 4. It is desirable that the deep bottom portion 32 has, for example, a depth d6 that is 0.55 to 0.65 times the depth d4 of the inner shoulder main groove 4. In the inner shoulder sipe 19 of the present embodiment, the shallow bottom portion 31 is provided on the outer side of the deep bottom portion 32 in the tire axial direction. Such an inner shoulder sipe 19 can maintain the rigidity near the inner tread end Ti of the inner shoulder land portion 11, and can prevent a decrease in steering stability.

FIG. 6 shows an enlarged view of the outer middle land portion 12. As shown in FIG. 6, the outer middle land portion 12 is provided with, for example, a plurality of outer middle lateral grooves 35 and a plurality of outer middle sipes 36. In the present embodiment, the outer middle lateral groove 35 and the outer middle sipe 36 are alternately provided in the tire circumferential direction.

The outer middle lateral groove 35 extends inward in the tire axial direction from, for example, the outer shoulder main groove 3 and is interrupted in the outer middle land portion 12. It is desirable that the outer middle lateral groove 35 has, for example, a length L5 in the tire axial direction that is 0.55 to 0.65 times the width W5 in the tire axial direction of the outer middle land portion 12. Such an outer middle lateral groove 35 can improve the wet performance while maintaining the rigidity of the outer middle land portion 12.

FIG. 7 shows a partially enlarged view of the outer shoulder lateral groove 16 and the outer middle lateral groove 35. As shown in FIG. 7, it is desirable that the outer middle lateral groove 35 is smoothly continuous with the outer shoulder lateral groove 16 via, for example, the outer shoulder main groove 3. As a result, during wet running, the outer middle lateral groove 35 and the outer shoulder lateral groove 16 can cooperate to discharge a large amount of water. In addition, in this specification, "two grooves or sipes smoothly continue through a main groove" means that at least one of the grooves is smoothly extended in the length direction of the one. It is assumed that more than half of the groove width of the groove overlaps with the other groove.

In the present embodiment, when each groove edge of the outer shoulder lateral groove 16 is smoothly extended in the length direction thereof, the amount of deviation P1 (not shown) of the outer middle lateral groove 35 from each groove edge of the outer middle lateral groove 35 is the outer middle lateral groove 35. It is desirable that the groove width is 0.10 times or less of W6. In a more desirable embodiment, the deviation amount P1 is 0.4 mm or less. Such an outer middle lateral groove 35 can guide the water in the groove to the outer shoulder lateral groove 16 side more smoothly during wet running.

FIG. 8A shows a sectional view taken along line DD of the outer middle lateral groove 35 of FIG. As shown in FIG. 8A, the outer middle lateral groove 35 of the present embodiment has, for example, a gradually increasing portion 37 and an outer portion 38. The depth of the gradually increasing portion 37 gradually increases toward the outside in the tire axial direction. The outer portion 38 is arranged on the outer side of the gradually increasing portion 37 in the tire axial direction and has a certain depth. Such an outer middle lateral groove 35 prevents a local change in the rigidity of the outer middle land portion 12, and thus suppresses uneven wear of the outer middle land portion 12.

In order to further exert the above-mentioned effect, the length L6 of the gradually increasing portion 37 in the tire axial direction is 0.35 to 0.45 times the width W5 of the outer middle land portion 12 in the tire axial direction (shown in FIG. 6). It is desirable to have it. It is desirable that the bottom surface of the gradually increasing portion 37 is inclined at an angle θ6 of 60 to 70 ° with respect to the normal line passing through the tread of the land portion, for example.

As shown in FIG. 6, the outer middle sipe 36 completely crosses, for example, the outer middle land portion 12. It is desirable that the outer middle sipe 36 is inclined in the same direction as the outer shoulder sipe 18 (shown in FIG. 2) with respect to the tire axial direction, for example. The angle θ7 of the outer middle sipe with respect to the tire axial direction is preferably, for example, 5 to 15 °.

As shown in FIG. 7, it is desirable that the outer middle sipe 36 is smoothly continuous with the outer shoulder sipe 18 via, for example, the outer shoulder main groove 3. As a result, the outer middle sipe 36 and the outer shoulder sipe 18 are easily opened when they touch the ground, so that a high frictional force can be obtained by these edges.

FIG. 8B shows a sectional view taken along line EE of the outer middle sipe 36 of FIG. As shown in FIG. 8B, it is desirable that the outer middle sipe 36 has, for example, a shallow bottom 39 and a deep bottom 40 having a depth greater than the shallow 39. In the outer middle sipe 36 of the present embodiment, the shallow bottom portion 39 is provided on the outer side of the deep bottom portion 40 in the tire axial direction.

It is desirable that the shallow bottom 39 depth d7 of the outer middle sipe 36 is, for example, 0.10 to 0.20 times the depth d1 of the outer shoulder main groove 3. It is desirable that the depth d8 of the deep bottom portion 40 of the outer middle sipe 36 is, for example, 0.55 to 0.65 times the depth d1 of the outer shoulder main groove 3. Such an outer middle sipe 36 can improve wet performance while suppressing uneven wear of the outer middle land portion 12.

FIG. 9 shows an enlarged view of the inner middle land portion 13 and the crown land portion 14. As shown in FIG. 9, the inner middle land portion 13 is provided with, for example, a plurality of inner middle sipes 42. In a preferred embodiment, the inner middle land portion 13 is provided with only the inner middle sipe 42 and is not provided with a groove having a width of 3 mm or more.

The inner middle sipe 42, for example, completely crosses the inner middle land portion 13. The inner middle sipe 42 is inclined in the direction opposite to the outer shoulder lateral groove 16 with respect to the tire axial direction, for example. It is desirable that the inner middle sipe 42 is inclined at an angle θ8 of 20 to 30 ° with respect to the tire axial direction, for example.

The inner middle sipe 42 has, for example, a central portion 43 in the tire axial direction and end portions 44 extending from the central portion 43 to the main grooves on both sides. For example, the central portion 43 and the end portion 44 of the present embodiment have different depths.

10 (a) shows a sectional view taken along line FF of the inner middle sipe 42 of FIG. 9, and FIG. 10 (b) shows a sectional view taken along line GG of the central portion 43 of FIG. Has been done. As shown in FIGS. 10A and 10B, the central portion 43 has, for example, a depth d9 of 1.0 to 2.0 mm. The central portion 43 of the present embodiment has, for example, a length L7 in the tire axial direction of 0.30 to 0.40 times the width W7 in the tire axial direction of the inner middle land portion 13 (shown in FIG. 9). It is desirable to have (shown). As a result, the rigidity of the inner middle land portion 13 is maintained, and excellent steering stability can be obtained.

FIG. 10 (c) shows a sectional view taken along line HH of the end portion 44 of FIG. As shown in FIG. 10 (c), the end portion 44 of this embodiment includes, for example, a first portion 45 and a second portion 46. The first portion 45 is opened, for example, with the same width as the central portion 43. In a preferred embodiment, the first portion 45 has, for example, the same depth as the central portion 43. The second portion 46 is arranged at the bottom of the first portion 45, for example, and extends in the tire radial direction with a width smaller than that of the first portion 45. Such end portions 44 can provide a large frictional force by the edges.

In order to improve the wet performance and the steering stability in a well-balanced manner, it is desirable that the depth d10 of the end portion 44 is, for example, 0.35 to 0.45 times the depth d4 of the inner shoulder main groove 4.

As shown in FIG. 9, the crown land portion 14 is provided with, for example, a plurality of crown sipes 47. In a preferred embodiment, the land portion 14 of the crown is provided with only the crown sipe 47 and is not provided with a groove having a width of 3 mm or more.

The crown sipe 47, for example, completely crosses the crown land portion 14. The crown sipe 47 of the present embodiment has, for example, a central portion 48 in the tire axial direction and end portions 49 extending from the central portion 48 to the main grooves on both sides. In the present embodiment, the central portion 48 of the crown sipe 47 has substantially the same cross-sectional shape as the central portion 43 of the inner middle sipe 42 (shown in FIG. 10B). The end portion 49 of the crown sipe 47 has substantially the same cross-sectional shape as the end portion 44 (shown in FIG. 10C) of the inner middle sipe 42.

The central portion 48 of the crown sipe 47 of the present embodiment is inclined with respect to the tire axial direction, for example. In a preferred embodiment, the central portion 48 of the crown sipe 47 is inclined in the opposite direction to the inner middle sipe 42. The angle θ9 of the central portion 48 of the crown sipe 47 with respect to the tire axial direction is preferably, for example, 50 to 70 °.

It is desirable that the end portion 49 of the crown sipe 47 is inclined in the direction opposite to the central portion with respect to the tire axial direction, for example. It is desirable that the end portion 49 is inclined at an angle θ10 of, for example, 20 to 30 ° with respect to the tire axial direction. The angle θ11 between the end portion 49 and the central portion 48 is preferably, for example, 80 to 100 °. Such a crown sipe 47 can exert frictional force in multiple directions due to its edge.

FIG. 10D shows a sectional view taken along line I-I of the crown sipe 47 of FIG. As shown in FIG. 10D, it is desirable that the end portion 49 of the crown sipe 47 has, for example, a depth d12 that is greater than the depth d11 of the central portion 48. It is desirable that the depth d12 of the end portion 49 is, for example, 3.0 to 3.5 times the depth d11 of the central portion 48. Such a crown sipe 47 can improve wet performance while maintaining the wear resistance of the crown land portion 14.

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 can be modified to various embodiments.

A size 255 / 55R18 pneumatic tire with the basic tread pattern of FIG. 1 was prototyped based on the specifications in Table 1. As a comparative example, a tire in which the second intersection and the third intersection are at the same position in the tire circumferential direction was prototyped. The uneven wear resistance and wet performance of each test tire were tested. The common specifications and test methods for each test tire are as follows.
Rim: 18 x 8.0J
Tire internal pressure: 240kPa

<Uneven wear resistance>
A wear energy measuring device was used to measure the wear energy of each shoulder land area. The result is an index with the wear energy of the comparative example as 100, and the smaller the value, the smaller the wear energy and the better the uneven wear resistance performance.

<Wet performance>
An inside drum tester was used, and the rate of occurrence of the hydroplaning phenomenon was measured when each test tire traveled on a drum surface at a depth of 5.0 mm under the following conditions. The result is an index with Comparative Example as 100, and the larger the value, the higher the generation rate and the better the wet performance.
Slip angle: 1.0 °
Vertical load: 4.2kN
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 uneven wear resistance while maintaining wet performance.

2 Tread part 10 Outer shoulder land part 11 Inner shoulder land part 16 Outer shoulder lateral groove 16a 1st groove edge 16b 2nd groove edge 17 Inner shoulder lateral groove 17a 3rd groove edge 17b 4th groove edge 21 1st intersection 22 2nd intersection 23 3rd intersection 24 4th intersection To Outer tread end Ti Inner tread end

Claims (6)

A tire that has a tread that is oriented to be mounted on a vehicle.
The tread portion includes an outer shoulder land portion including an outer tread end located on the outside of the vehicle when mounted on the vehicle, and an inner shoulder land portion including an inner tread end located on the inside of the vehicle when mounted on the vehicle.
The outer shoulder land portion is provided with a plurality of outer shoulder lateral grooves extending inward in the tire axial direction from at least the outer tread end.
The inner shoulder land portion is provided with a plurality of inner shoulder lateral grooves extending inward in the tire axial direction from at least the inner tread end.
Each of the outer shoulder lateral grooves is a first groove edge located in the first direction, which is one side in the tire circumferential direction, and a second groove located in the second direction opposite to the first direction in the tire circumferential direction. It has an edge, and the first groove edge and the second groove edge intersect with the outer tread end at the first intersection and the second intersection, respectively.
Each inner shoulder lateral groove has a third groove edge located in the first direction in the tire circumferential direction and a fourth groove edge located in the second direction in the tire peripheral direction, and the third groove edge and the first groove edge. The four groove edges intersect the inner tread end at the third and fourth intersections, respectively.
The first intersection and the second intersection point, respectively, in the third intersection and the tire circumferential direction and the fourth intersection, Ri Contact disposed at different positions,
In the group of the first to fourth intersections located closest to each other in the tire circumferential direction, the tire circumference is in the order of the first intersection, the second intersection, the third intersection, and the fourth intersection toward the second direction. Lined up in the direction
The distance L1 in the tire circumferential direction between the second intersection and the third intersection is larger than the groove width at the outer tread end of the outer shoulder lateral groove and the groove width at the inner tread end of the inner shoulder lateral groove. Small tires. The tire according to claim 1, wherein the distance L1 is 0.2 to 1.0 mm. A tire that has a tread that is oriented to be mounted on a vehicle.
The tread portion includes an outer shoulder land portion including an outer tread end located on the outer side of the vehicle when mounted on the vehicle, and an inner shoulder land portion including an inner tread end located on the inner side of the vehicle when mounted on the vehicle.
The outer shoulder land portion is provided with a plurality of outer shoulder lateral grooves extending inward in the tire axial direction from at least the outer tread end.
The inner shoulder land portion is provided with a plurality of inner shoulder lateral grooves extending inward in the tire axial direction from at least the inner tread end.
Each of the outer shoulder lateral grooves is a first groove edge located in the first direction, which is one side in the tire circumferential direction, and a second groove located in the second direction opposite to the first direction in the tire circumferential direction. It has an edge, and the first groove edge and the second groove edge intersect with the outer tread end at the first intersection and the second intersection, respectively.
Each inner shoulder lateral groove has a third groove edge located in the first direction in the tire circumferential direction and a fourth groove edge located in the second direction in the tire peripheral direction, and the third groove edge and the first groove edge. The four groove edges intersect the inner tread end at the third and fourth intersections, respectively.
The first intersection and the second intersection are provided at different positions in the tire circumferential direction from the third intersection and the fourth intersection, respectively.
The outer shoulder lateral groove and the inner shoulder lateral groove each have an angle of less than 10 ° with respect to the tire axial direction.
A tire in which the maximum angle of the inner shoulder lateral groove with respect to the tire axial direction is smaller than the maximum angle of the outer shoulder lateral groove with respect to the tire axial direction. A tire that has a tread that is oriented to be mounted on a vehicle.
The tread portion includes an outer shoulder land portion including an outer tread end located on the outer side of the vehicle when mounted on the vehicle, and an inner shoulder land portion including an inner tread end located on the inner side of the vehicle when mounted on the vehicle.
The outer shoulder land portion is provided with a plurality of outer shoulder lateral grooves extending inward in the tire axial direction from at least the outer tread end.
The inner shoulder land portion is provided with a plurality of inner shoulder lateral grooves extending inward in the tire axial direction from at least the inner tread end.
Each of the outer shoulder lateral grooves is a first groove edge located in the first direction, which is one side in the tire circumferential direction, and a second groove located in the second direction opposite to the first direction in the tire circumferential direction. It has an edge, and the first groove edge and the second groove edge intersect with the outer tread end at the first intersection and the second intersection, respectively.
Each inner shoulder lateral groove has a third groove edge located in the first direction in the tire circumferential direction and a fourth groove edge located in the second direction in the tire peripheral direction, and the third groove edge and the first groove edge. The four groove edges intersect the inner tread end at the third and fourth intersections, respectively.
The first intersection and the second intersection are provided at different positions in the tire circumferential direction from the third intersection and the fourth intersection, respectively.
An outer shoulder sipe is provided on the outer shoulder land portion.
An inner shoulder sipe is provided on the inner shoulder land portion.
The outer shoulder sipe and the inner shoulder sipe each have a shallow bottom portion and a deep bottom portion having a depth larger than the shallow bottom portion.
The outer shoulder sipe has a shallow bottom portion provided inside the deep bottom portion in the tire axial direction.
The inner shoulder sipe is a tire in which the shallow bottom portion is provided on the outer side of the deep bottom portion in the tire axial direction. The tire according to any one of claims 1 to 4, wherein the outer shoulder lateral groove completely crosses the outer shoulder land portion. The tire according to any one of claims 1 to 5, wherein the inner end of the inner shoulder lateral groove in the tire axial direction is located in the inner shoulder land portion.

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