JP6973041B2 - tire - Google Patents

Description

The present invention relates to a tire whose mounting direction on a vehicle is specified.

For example, Patent Document 1 below proposes a tire having a tread portion in which a vehicle mounting direction is specified. The tread portion of this tire has a first main groove located on the outside of the vehicle on the equator of the tire and a narrow groove located on the outside of the vehicle of the first main groove and having a groove width narrower than that of the first main groove. .. This tire is expected to have a relatively high rigidity in the land area between the first main groove and the narrow groove, and to improve the steering stability in the middle of turning when sufficient ground pressure acts on this land area. doing.

Japanese Unexamined Patent Publication No. 2016-0743886

However, in the tire, in the initial stage of turning where the contact pressure acting on the land portion is not sufficiently increased, it is difficult for the land portion to follow the road surface, and there is room for improvement in the initial responsiveness at the time of turning.

The present invention has been devised in view of the above problems, and an object of the present invention is to provide a tire capable of exhibiting excellent initial responsiveness.

The present invention is a tire having a tread portion whose mounting direction on a vehicle is specified, and the tread portion has an outer tread end located on the outside of the vehicle when mounted on the vehicle and an inner side located on the inside of the vehicle when mounted on the vehicle. The tread end includes a plurality of main grooves continuously extending in the tire circumferential direction, and a plurality of land portions divided by the main grooves, and the land portion is the outer shoulder arranged on the outermost tread end side. The land portion includes an outer middle land portion adjacent to the outer shoulder land portion, an inner shoulder land portion arranged on the innermost tread end side, and an inner middle land portion adjacent to the inner shoulder land portion. The main groove includes an outer shoulder main groove extending between the outer shoulder land portion and the outer middle land portion and having the smallest groove width among the plurality of main grooves, and the outer shoulder land portion, the inner side. Each of the shoulder land portion and the inner middle land portion is provided with a plurality of lateral grooves extending in the tire axial direction, and the outer middle land portion is provided with the inner side from the edge of the outer middle land portion on the outer tread end side. A plurality of outer middle lateral grooves extending toward the end of the tread and interrupting in the outer middle land portion are provided, and each outer middle lateral groove is inclined at an angle larger than each of the plurality of lateral grooves with respect to the tire axial direction. There is.

In the tire of the present invention, it is desirable that the groove width of the outer shoulder main groove is 0.50 to 0.65 times the maximum groove width among the plurality of main grooves.

In the tire of the present invention, it is desirable that the outer middle lateral groove includes a first groove portion extending at a constant depth and a second groove portion whose depth gradually decreases toward the inner tread end side.

In the tire of the present invention, it is desirable that the first groove portion communicates with the outer shoulder main groove.

In the tire of the present invention, it is desirable that the second groove portion includes a portion having a depth larger than that of the first groove portion.

In the tire of the present invention, it is desirable that the length of the outer middle lateral groove in the tire axial direction is 0.50 to 0.80 times the width of the outer middle land portion in the tire axial direction.

In the tire of the present invention, the land portion includes a crown land portion between the outer middle land portion and the inner middle land portion, and the crown land portion includes the outer tread from an edge on the inner tread end side. It is desirable to have an inner slot that extends to the end and is interrupted within the land of the crown.

In the tire of the present invention, the outer middle lateral groove includes a first groove portion extending at a constant depth and a second groove portion whose depth gradually decreases toward the inner tread end side, and the maximum depth of the inner slot. It is desirable that the tire is 1.35 to 1.70 times the depth of the first groove.

In the tire of the present invention, it is desirable that the length of the inner slot in the tire axial direction is 0.30 to 0.50 times the width of the crown land portion in the tire axial direction.

In the tire of the present invention, it is desirable that the lateral groove includes an inner middle lateral groove that crosses the inner middle land portion, and the inner middle lateral groove is smoothly continuous with the inner slot via the main groove.

In the tire of the present invention, it is desirable that the maximum angle of the inner middle lateral groove with respect to the tire axial direction is 0.20 to 0.30 times the angle of the outer middle lateral groove with respect to the tire axial direction.

In the tire of the present invention, it is desirable that the lateral groove includes an inner shoulder lateral groove that crosses the inner shoulder land portion, and the inner shoulder lateral groove is smoothly continuous with the inner middle lateral groove via the main groove.

In the tire of the present invention, it is desirable that the maximum angle of the inner shoulder lateral groove with respect to the tire axial direction is smaller than the maximum angle of the inner middle lateral groove with respect to the tire axial direction.

In the tire of the present invention, the tread portion includes an outer tread portion between the outer tread end and the tire equatorial line, and an inner tread portion between the inner tread end and the tire equatorial line, and the outer tread portion includes the outer tread portion. , It is desirable to have a land ratio larger than that of the inner tread portion.

The outer middle land portion divided into the tread portion of the tire of the present invention is provided with a plurality of outer middle lateral grooves extending from the outer tread end side edge of the outer middle land portion to the inner tread end side and interrupted in the outer middle land portion. It has been. Further, each outer middle lateral groove of the present invention is inclined at an angle larger than each of the plurality of lateral grooves with respect to the tire axial direction.

The outer middle land area tends to have a larger contact pressure than the outer shoulder land area at the initial stage of turning, and the inner shoulder land area and the inner middle land area tend to have a larger contact pressure during the turn. be. For this reason, the lateral groove arranged in the outer middle land area tends to have a large influence on the initial responsiveness and steering stability. In the present invention, the rigidity of the land portion around the outer middle lateral groove can be appropriately relaxed by the outer middle lateral groove. Therefore, the land portion can easily follow the road surface even at the initial stage of turning where the ground pressure is not sufficiently increased, and the initial responsiveness can be remarkably improved.

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 middle land part of FIG. (A) is a sectional view taken along line AA of FIG. 2, and FIG. 2B is a sectional view taken along line BB of FIG. It is an enlarged view of the outer shoulder land part of FIG. (A) is a sectional view taken along line CC of FIG. 4, and (b) is a sectional view taken along line DD of FIG. It is an enlarged view of the crown land part of FIG. FIG. 6 is a cross-sectional view taken along the line EE of FIG. It is an enlarged view of the inner middle land part and the inner shoulder land part of FIG. (A) is a sectional view taken along line FF of FIG. 8, (b) is a sectional view taken along line GG of FIG. 8, and (c) is a sectional view taken along line HF of FIG. .. It is an enlarged view of the outer middle land part of the tire of the comparative example.

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 is used for various tires such as pneumatic tires for heavy loads and non-pneumatic tires in which pressurized air is not filled inside the tires. Can be done.

As shown in FIG. 1, the tire 1 has a tread portion 2 in which the direction of attachment to the vehicle is specified. The tread portion 2 of the present embodiment includes, for example, a tread pattern that is asymmetric with respect to the tire equator C. The tread portion 2 has an outer tread end To located on the outer side of the vehicle when the tire 1 is mounted on the vehicle, and an inner tread end Ti located on the inner side 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 portion (not shown), for example.

In the case of a pneumatic tire, each tread end To and Ti are the most outer 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 touches 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 filled, 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 a 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 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. "Maximum load capacity" for JATTA and "TIRE LOAD LIMITS" for TRA. The maximum value described in "AT VARIOUS COLD INFLATION PRESSURES", or "LOAD CAPACITY" for ETRTO.

The tread portion 2 includes a plurality of main grooves 3 continuously extending in the tire circumferential direction, and a plurality of land portions 4 divided by the main groove 3. Each main groove 3 has, for example, a groove width of 2% or more of 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. The tread portion 2 of the present embodiment has, for example, five land portions 4 divided by four main grooves 3. However, the present invention is not limited to such an aspect.

The main groove 3 includes, for example, an outer shoulder main groove 5, an inner shoulder main groove 6, an outer crown main groove 7, and an inner crown main groove 8. The outer shoulder main groove 5 is provided on the outermost tread end To side of the plurality of main grooves 3. The inner shoulder main groove 6 is provided on the innermost tread end Ti side of the plurality of main grooves 3. The outer crown main groove 7 is provided, for example, between the outer shoulder main groove 5 and the tire equator C. The inner crown main groove 8 is provided, for example, between the inner shoulder main groove 6 and the tire equator C.

For the outer shoulder main groove 5 and the inner shoulder main groove 6, for example, it is desirable that the distance L1 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 7 and the inner crown main groove 8, for example, it is desirable that the distance L2 from the tire equator C to the groove center line is 0.05 to 0.15 times the tread width TW.

The outer shoulder main groove 5 has the smallest groove width W1 among the plurality of main grooves. It is desirable that the groove width W1 of the outer shoulder main groove 5 is, for example, 0.50 to 0.65 times the maximum groove width among the plurality of main grooves. The groove width W2 of the inner shoulder main groove 6, the groove width W3 of the outer crown main groove 7, and the groove width W4 of the inner crown main groove 8 are, for example, 5.5% to 7.5% of the tread width TW. desirable. It is desirable that each of the main grooves 5 to 8 has a groove depth of, for example, 5.0 to 12.0 mm. In a more preferred embodiment, the outer shoulder main groove 5 has the smallest groove depth of the plurality of main grooves.

The land portion 4 includes an outer shoulder land portion 11, an outer middle land portion 12, an inner shoulder land portion 13, and an inner middle land portion 14. Further, the land portion 4 of the present embodiment includes the crown land portion 15. The outer shoulder land portion 11 is arranged on the outermost tread end To side of the plurality of land portions 4. The inner shoulder land portion 13 is arranged on the innermost tread end Ti side of the plurality of land portions 4. The outer middle land portion 12 is adjacent to the inner tread end Ti side of the outer shoulder land portion 11. The inner middle land portion 14 is adjacent to the outer tread end To side of the inner shoulder land portion 13. The crown land portion 15 is arranged between the outer middle land portion 12 and the inner middle land portion 14.

Each of the outer shoulder land portion 11, the inner shoulder land portion 13, and the inner middle land portion 14 is provided with a plurality of lateral grooves 20 extending in the tire axial direction. The lateral groove 20 has, for example, a groove width W5 of 1.0% to 2.0% of the tread width TW. The lateral groove 20 has a groove depth of, for example, 3.0 to 8.0 mm. The lateral groove 20 is provided, for example, at an angle θ1 of 0 to 15 ° with respect to the tire axial direction. A more detailed configuration of the lateral groove 20 provided in each land portion will be described later.

FIG. 2 shows an enlarged view of the outer middle land portion 12. As shown in FIG. 2, the outer middle land portion 12 is provided with a plurality of outer middle lateral grooves 23. Each outer middle lateral groove 23 extends from the edge 12a on the outer tread end To side of the outer middle land portion 12 to the inner tread end Ti side, and is interrupted in the outer middle land portion 12. Further, each outer middle lateral groove 23 of the present invention is inclined with respect to the tire axial direction at an angle θ2 larger than that of the lateral groove 20 provided in the other land portion. In other words, each outer middle lateral groove 23 of the present invention is inclined with respect to the tire circumferential direction at an angle smaller than that of the lateral groove 20 provided in the other land portion.

In a preferred embodiment, in any portion of the outer middle lateral groove 23, the angle with respect to the tire axial direction is larger than the maximum angle with respect to the tire axial direction of the lateral groove 20 provided in the other land portion. In a more desirable embodiment, the angle of the straight line connecting both ends of the groove center of the outer middle lateral groove 23 with respect to the tire axial direction is larger than the maximum angle of the lateral groove 20 with respect to the tire axial direction.

The outer middle land portion 12 tends to have a contact pressure higher than that of the outer shoulder land portion 11 at the initial stage of turning, and the contact pressure higher than that of the inner shoulder land portion 13 and the inner middle land portion 14 during the turn. Tends to work. Therefore, the lateral groove arranged in the outer middle land portion 12 tends to have a large influence on the initial responsiveness and steering stability. In the present invention, the outer middle lateral groove 23 can appropriately relax the rigidity of the land portion around the outer middle lateral groove 23. Therefore, the land portion can easily follow the road surface even at the initial stage of turning where the ground pressure is not sufficiently increased, and the initial responsiveness can be remarkably improved.

In order to improve the wear resistance and the initial response in a well-balanced manner, it is desirable that the angle θ2 of the outer middle lateral groove 23 is, for example, 45 to 60 °. Further, the outer middle lateral groove 23 of the present embodiment is slightly curved so that the angle θ2 gradually decreases toward the inner tread end Ti side.

From the same viewpoint, it is desirable that the length L5 of the outer middle lateral groove 23 in the tire axial direction is, for example, 0.50 to 0.80 times the width W8 of the outer middle land portion 12 in the tire axial direction.

It is desirable that the outer middle lateral groove 23 has, for example, a groove width W6 of 0.8% to 1.6% of the tread width TW. Such an outer middle lateral groove 23 helps to improve the initial responsiveness and steering stability in a well-balanced manner.

FIG. 3A shows a sectional view taken along line AA of the outer middle lateral groove 23. As shown in FIG. 3A, the outer middle lateral groove 23 includes, for example, a first groove portion 23a and a second groove portion 23b. The first groove portion 23a communicates with, for example, the outer shoulder main groove 5 and extends at a constant depth. The second groove portion 23b communicates with the inner tread end Ti side of the first groove portion 23a, and the depth gradually decreases toward the inner tread end Ti side. As a result, the central portion of the outer portion 32 in the tire axial direction is easily deformed appropriately to improve the initial response, and uneven wear of the land portion near the outer shoulder main groove 5 and the middle vertical fine groove 30 is suppressed. Will be done.

It is desirable that the depth d2 of the first groove portion 23a is, for example, 0.45 to 0.55 times the groove depth d1 of the outer shoulder main groove 5. As a result, wear resistance and steering stability are improved in a well-balanced manner.

The second groove portion 23b includes, for example, a portion having a greater depth than the first groove portion 23a. The maximum depth d3 of the second groove portion 23b is, for example, 1.40 to 1.60 times the depth d2 of the first groove portion 23a. In the present embodiment, the second groove portion 23b is configured by gradually reducing the depth from the deepest portion of the outer middle lateral groove 23 toward the inner tread end Ti side.

As shown in FIG. 2, the outer middle land portion 12 is divided into, for example, a middle vertical groove 30 extending continuously in the tire circumferential direction and an outer portion 32 divided into the outer tread end To side of the middle vertical groove 30. And the inner portion 31 divided on the inner tread end Ti side of the middle vertical narrow groove 30. In the present embodiment, the outer middle lateral groove 23 is provided in the outer portion 32, and each outer middle lateral groove 23 communicates with the middle vertical narrow groove 30.

The middle vertical groove 30 extends linearly along the tire circumferential direction, for example. The middle vertical groove 30 of the present embodiment is arranged, for example, on the inner tread end Ti side of the outer middle land portion 12 from the center position in the tire axial direction. However, the middle vertical groove 30 is not limited to such an aspect.

The middle vertical groove 30 has, for example, a groove width W7 of less than 2% of the tread width TW. It is desirable that the groove width W7 of the middle vertical narrow groove 30 is, for example, 3% to 10% of the width W8 of the outer middle land portion 12 in the tire axial direction. More specifically, it is desirable that the groove width W7 is, for example, 0.8 to 2.0 mm.

FIG. 3B shows a cross-sectional view taken along the line BB of the middle vertical groove 30 of FIG. As shown in FIG. 3B, it is desirable that the depth d4 of the middle vertical groove 30 is, for example, 0.30 to 0.45 times the depth d1 of the outer shoulder main groove 5. Such a middle vertical groove 30 enhances wear resistance and steering stability in a well-balanced manner.

As shown in FIG. 2, it is desirable that the inner portion 31 of the present embodiment is configured as, for example, a plain rib without grooves or sipes. Such an inner portion 31 can exhibit excellent steering stability, suppress deformation of the groove wall of the outer crown main groove 7, and reduce the air column resonance sound thereof.

In order to improve the initial response and wear resistance in a well-balanced manner, the tire axial width W9 of the inner portion 31 is, for example, 0.20 to 0.40 times the tire axial width W8 of the outer middle land portion 12. Is desirable.

FIG. 4 shows an enlarged view of the outer shoulder land portion 11. As shown in FIG. 4, the outer shoulder land portion 11 is provided with a plurality of outer shoulder lateral grooves 38 extending in the tire axial direction and an outer shoulder lateral narrow groove 39 having a groove width smaller than that of the outer shoulder lateral groove 38. There is. In a preferred embodiment, the outer shoulder lateral grooves 38 and the outer shoulder lateral fine grooves 39 are provided alternately in the tire circumferential direction.

The outer shoulder lateral groove 38 completely crosses, for example, the outer shoulder land portion 11. The outer shoulder lateral groove 38 is inclined in the same direction as the outer middle lateral groove 23 with respect to the tire axial direction, for example. The angle θ4 of the outer shoulder lateral groove 38 with respect to the tire axial direction is preferably, for example, 5 to 15 °.

It is desirable that the groove width W10 of the outer shoulder lateral groove 38 is larger than, for example, the groove width W6 (shown in FIG. 2) of the outer middle lateral groove 23. It is desirable that the groove width W10 of the outer shoulder lateral groove 38 is, for example, 1.30 to 1.70 times the groove width W6 of the outer middle lateral groove 23. Such an outer shoulder lateral groove 38 helps to improve wet performance and steering stability in a well-balanced manner.

FIG. 5A shows a sectional view taken along line CC of the outer shoulder lateral groove 38. As shown in FIG. 5A, the outer shoulder lateral groove 38 is connected to, for example, a first groove portion 38a on the outer tread end To side and a second groove portion 38a having a depth smaller than that of the first groove portion 38a. It has a groove 38b. The depth d6 of the second groove portion 38b is, for example, 0.60 to 0.75 times the depth d5 of the first groove portion 38a. Such an outer shoulder lateral groove 38 suppresses deformation of the land portion of the second groove portion 38b to improve steering stability, and makes it easier for the land portion near the first groove portion 38a to be appropriately deformed to enhance the initial response. Can be done.

As shown in FIG. 4, the outer shoulder lateral groove 39 is inclined in the same direction as, for example, the outer shoulder lateral groove 38. The outer shoulder lateral groove 39 of the present embodiment extends along, for example, the outer shoulder lateral groove 38.

It is desirable that the groove width W11 of the outer shoulder lateral groove 39 is, for example, 0.40 to 0.60 times the groove width W10 of the outer shoulder lateral groove 38. The outer shoulder lateral groove 39 of the present embodiment has, for example, an opening width of 1.5 mm or more on the tread surface of the land portion. However, the present invention is not limited to such an aspect, and the outer shoulder lateral groove 39 may be configured as a sipe. As used herein, "sipe" means a notch with a width of less than 1.5 mm.

FIG. 5B shows a cross-sectional view taken along the line DD of the outer shoulder lateral groove 39. As shown in FIG. 5B, the outer shoulder lateral groove 39 of the present embodiment has, for example, an opening 28 having the above-mentioned opening width and a sipe portion extending in the tire radial direction with a width of less than 1.5 mm. 29 and is included. Such an outer shoulder lateral narrow groove 39 can prevent an excessive decrease in rigidity of the outer shoulder land portion 11 and can improve initial responsiveness and wear resistance in a well-balanced manner.

FIG. 6 shows an enlarged view of the land portion 15 of the crown. As shown in FIG. 6, it is desirable that the land portion 15 of the crown extends continuously, for example, in the tire circumferential direction. Such a crown land portion 15 can increase the rigidity of the tread portion 2 near the tire equator C together with the inner portion 31 of the outer middle land portion 12 described above, and can provide a large cornering force during turning.

It is desirable that the crown land portion 15 is provided with, for example, a plurality of outer recesses 33 and a plurality of inner slots 34. In the present embodiment, the outer recess 33 and the inner slot 34 are provided at the same pitch as the outer middle lateral groove 23. The outer recess 33 is recessed from the edge 15a on the outer tread end To side of the crown land portion 15 to the inner tread end Ti side. The inner slot 34 extends from the edge 15b on the inner tread end Ti side of the crown land portion 15 to the outer tread end To side and is interrupted in the crown land portion 15.

The outer recess 33 includes, for example, a first edge 33a and a second edge 33b that are inclined in opposite directions on the tread of the land portion. The first edge 33a is inclined at an angle θ5 of, for example, 50 to 70 ° with respect to the tire axial direction. The second edge 33b is inclined at an angle θ6 smaller than that of the first edge 33a in the tire axial direction, for example. Specifically, the angle θ6 of the second edge 33b is, for example, 0 to 10 °.

It is desirable that the width W12 of the outer recess 33 in the tire axial direction is smaller than the width W9 of the inner portion 31 of the outer middle land portion 12 in the tire axial direction (shown in FIG. 2). Such an outer recess 33 can be expected to uniformly bring the progress of wear between the crown land portion 15 and the outer middle land portion 12 closer to each other, and thus to improve the wear resistance.

It is desirable that the inner slot 34 is inclined in the same direction as the outer middle lateral groove 23 with respect to the tire axial direction, for example. The angle θ7 of the inner slot 34 with respect to the tire axial direction is preferably, for example, 10 to 25 °.

It is desirable that the length L6 of the inner slot 34 in the tire axial direction is larger than, for example, the width W12 of the outer recess 33. In the present embodiment, the crown land portion 15 is provided on the tire equator C, and the inner slots 34 are arranged so as not to straddle the tire equator C. More specifically, it is desirable that the length L6 of the inner slot 34 is, for example, 0.30 to 0.50 times the width W13 of the crown land portion 15 in the tire axial direction. Such an inner slot 34 can moderately easily deform the land portion 15 of the crown and enhance the initial responsiveness.

In a more preferred embodiment, the length L6 of the inner slot 34 is smaller than the tire axial length L5 of the outer middle lateral groove 23. Specifically, it is desirable that the length L6 of the inner slot 34 is 0.45 to 0.65 times the length L5 of the outer middle lateral groove 23. Such an inner slot 34 helps to evenly approach the progress of wear between the crown land portion 15 and the outer middle land portion 12.

FIG. 7 shows a sectional view taken along line EE of the outer recess 33 and the inner slot 34. As shown in FIG. 7, it is desirable that the maximum depth d8 of the outer recess 33 is 0.25 to 0.47 times the maximum depth d7 of the main groove.

It is desirable that the inner slot 34 gradually increases in depth toward, for example, the inner tread end Ti side. The maximum depth d9 of the inner slot 34 is greater than, for example, the maximum depth d8 of the outer recess 33. In a more preferred embodiment, the depth d9 of the inner slot 34 is, for example, 1.30 to 1.70 times the depth d2 (shown in FIG. 3A) of the first groove portion 23a of the outer middle lateral groove 23. .. Such an inner slot 34 can improve the initial response and the wear resistance in a well-balanced manner.

FIG. 8 shows an enlarged view of the inner middle land portion 14 and the inner shoulder land portion 13. As shown in FIG. 8, the inner middle land portion 14 is provided with, for example, a plurality of inner middle lateral grooves 41 and a plurality of inner middle sipes 42. In the present embodiment, the inner middle lateral grooves 41 and the inner middle sipes 42 are alternately provided in the tire circumferential direction.

The inner middle lateral groove 41 completely crosses, for example, the inner middle land portion 14. The inner middle lateral groove 41 is inclined in the same direction as the inner slot 34 with respect to the tire axial direction, for example. The angle θ8 of the inner middle lateral groove 41 with respect to the tire axial direction is preferably, for example, 10 to 18 °.

In the present embodiment, the inner middle lateral groove 41 is slightly curved, and the angle of the groove center line with respect to the tire axial direction gradually decreases toward the inner tread end Ti. The maximum angle θ9 of the groove center line of the inner middle lateral groove 41 with respect to the tire axial direction (corresponding to the angle at the end of the outer tread end To side in the present embodiment) is, for example, with respect to the tire axial direction of the outer middle lateral groove 23. It is desirable that the angle θ2 is 0.20 to 0.30 times. As a result, the rigidity of the land portion in the vicinity of the inner middle lateral groove 41 in the tire axial direction is increased, and a large cornering force can be obtained in the middle of turning.

As shown in FIG. 1, it is desirable that the inner middle lateral groove 41 is smoothly continuous with the inner slot 34 via the inner crown main groove 8. Such an inner middle lateral groove 41 can exhibit high drainage together with the inner slot 34. The phrase "provided at a position where the grooves or slots are smoothly continuous" includes at least an embodiment in which a region in which one groove or slot is virtually extended intersects with a region in which the other groove or slot is virtually extended. As a more desirable embodiment, in the present embodiment, a region in which the inner middle lateral groove 41 is virtually extended intersects with the end portion of the inner slot 34 on the inner crown main groove 8 side. Further, a region in which the inner slot 34 is virtually extended intersects with the end portion of the inner middle lateral groove 41 on the inner crown main groove 8 side.

FIG. 9A shows a sectional view taken along line FF of the inner middle lateral groove 41 of FIG. As shown in FIG. 9A, the inner middle lateral groove 41 includes a shallow bottom groove portion 41b having a depth smaller than each end portion 41a between the end portions 41a on both sides in the tire axial direction. The depth d11 of the shallow bottom groove portion 41b is, for example, 0.30 to 0.40 times the depth d10 of the end portion 41a. Such an inner middle lateral groove 41 can improve the wet performance while maintaining the rigidity of the inner middle land portion 14.

As shown in FIG. 8, the inner middle sipe 42 completely crosses, for example, the inner middle land portion 14. The inner middle sipe 42 is inclined in the same direction as the inner middle lateral groove 41 with respect to the tire axial direction, for example, and extends along the inner middle lateral groove 41 in a more desirable embodiment.

FIG. 9B shows a sectional view taken along line GG of the inner middle sipe 42 of FIG. As shown in FIG. 9B, the inner middle sipe 42 includes, for example, a shallow bottom sipe 42b having a depth smaller than each end 42a between the ends 42a on both sides in the tire axial direction. There is. The depth d13 of the shallow bottom sipe portion 42b is, for example, 0.40 to 0.55 times the depth d12 of the end portion 42a. Such an inner middle sipe 42 can improve the initial responsiveness and the wear resistance in a well-balanced manner.

In a more preferred embodiment, the depth d12 of the end 42a of the inner middle sipe 42 is smaller than the depth d10 of the end 41a of the inner middle lateral groove 41. On the other hand, the depth d13 of the shallow bottom sipe portion 42b of the inner middle sipe 42 is larger than the depth d11 of the shallow bottom groove portion 41b of the inner middle lateral groove 41. Such an inner middle lateral groove 41 and an inner middle sipe 42 can suppress uneven wear of the inner middle land portion 14.

As shown in FIG. 8, the inner shoulder land portion 13 is provided with, for example, a plurality of inner shoulder lateral grooves 43 and a plurality of inner shoulder sipes 44. In the present embodiment, the inner shoulder lateral grooves 43 and the inner shoulder sipes 44 are alternately provided in the tire circumferential direction.

The inner shoulder lateral groove 43 completely crosses, for example, the inner shoulder land portion 13. The inner middle lateral groove 41 is inclined in the same direction as the inner middle lateral groove 41 with respect to the tire axial direction, for example. The angle θ10 of the inner shoulder lateral groove 43 with respect to the tire axial direction is preferably less than, for example, 10 °.

In the present embodiment, the inner shoulder lateral groove 43 is slightly curved, and the angle of the groove center line with respect to the tire axial direction gradually decreases toward the inner tread end Ti. The maximum angle θ11 of the groove center line of the inner shoulder lateral groove 43 with respect to the tire axial direction (corresponding to the angle at the end on the outer tread end To side in the present embodiment) is, for example, with respect to the tire axial direction of the inner middle lateral groove 41. It is desirable that the angle is smaller than the maximum angle θ9.

It is desirable that the inner shoulder lateral groove 43 is smoothly continuous with the inner middle lateral groove 41 via the inner shoulder main groove 6. As a more desirable embodiment, in the present embodiment, a region in which the inner shoulder lateral groove 43 is virtually extended intersects with the end portion of the inner middle lateral groove 41 on the inner shoulder main groove 6 side. Further, a region in which the inner middle lateral groove 41 is virtually extended intersects with the end portion of the inner shoulder lateral groove 43 on the inner shoulder main groove 6 side. Such an inner shoulder lateral groove 43 can exhibit excellent drainage.

In the present embodiment, the inner slot 34, the inner middle lateral groove 41 and the inner shoulder lateral groove 43 are smoothly continuous via the main groove, and the angle with respect to the tire axial direction thereof gradually decreases from the inner end of the inner slot 34 to the inner tread end Ti. It is desirable to do. Such a lateral groove arrangement helps to further enhance wet performance.

FIG. 9 (c) shows a sectional view taken along line OH of the inner shoulder lateral groove 43. As shown in FIG. 9 (c), the inner shoulder lateral groove 43 includes, for example, a first groove portion 43a and a second groove portion 43b connected to the inner shoulder main groove 6 and having a depth smaller than that of the first groove portion 43a. I'm out. The depth d15 of the second groove portion 43b is, for example, 0.60 to 0.70 times the depth d14 of the first groove portion 43a. Such an inner shoulder lateral groove 43 can exhibit excellent steering stability and wet performance.

As shown in FIG. 8, the inner shoulder sipe 44 completely crosses, for example, the inner shoulder land portion 13. The inner shoulder sipe 44 is inclined, for example, in the same direction as the inner shoulder lateral groove 43 with respect to the tire axial direction, and more preferably extends along the inner shoulder lateral groove 43.

It is desirable that the inner shoulder sipe 44 is smoothly continuous with the inner middle sipe 42, for example, via the inner shoulder main groove 6. Such an inner shoulder sipe 44 can moderately easily deform the inner shoulder land portion 13 and enhance the initial responsiveness.

As shown in FIG. 1, the land ratio LT of the tread portion 2 is preferably, for example, 60% to 70%. In the present specification, the “land ratio” is the ratio Sb / Sa of the actual total ground contact area Sb to the total area Sa of the virtual ground contact surface that fills all the grooves, sipes, and slots provided in the tread portion 2. Is.

The tread portion 2 includes an outer tread portion 2A between the outer tread end To and the tire equator C, and an inner tread portion 2B between the inner tread end Ti and the tire equator C. The outer tread portion 2A preferably has a larger land ratio than the inner tread portion 2B. Specifically, the land ratio LA of the outer tread portion 2A is preferably, for example, 60% to 80%. The land ratio LB of the inner tread portion 2B is preferably, for example, 55% to 75%. Such a tread portion 2 can exhibit a large cornering force in the middle of turning while exhibiting excellent initial responsiveness.

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 into various embodiments.

A tire of size 215 / 60R16 having the basic pattern of FIG. 1 was prototyped. As a comparative example, as shown in FIG. 10, a tire provided with a plurality of outer middle lateral grooves b extending at the same angle as the inner middle lateral groove and completely crossing the land portion on the outer middle lateral groove a was prototyped. The tread portion of the tire of the comparative example is substantially the same as the tread portion shown in FIG. 1 except for the above points. The steering stability and wear resistance of each test tire were tested. The common specifications and test methods for each test tire are as follows.
Mounting rim: 16 x 6.5J
Tire internal pressure: 210kPa
Test vehicle: Displacement 2500cc, rear-wheel drive vehicle Tire mounting position: All wheels

<Maneuvering stability>
The steering stability including the initial responsiveness when traveling on a dry road surface with the above test vehicle was evaluated by the driver's sensuality. The result is a score with a comparative example of 100, and the larger the value, the better the steering stability including the initial responsiveness.

<Abrasion resistance>
A wear energy measuring device was used to measure the difference in wear energy between the outer middle land and the crown land. The result is an index with the difference in wear energy of the comparative example as 100. The smaller the value, the smaller the difference in wear energy, the uniform progress of wear between the outer middle land part and the crown land part, and the resistance to resistance. Shows excellent wear resistance.
The test results are shown in Table 1.

As a result of the test, it was confirmed that the tires of the examples had improved steering stability including initial responsiveness. It was also confirmed that the tires of the examples maintained their wear resistance.

2 Tread part 3 Main groove 4 Land part 5 Outer shoulder main groove 11 Outer shoulder land part 12 Outer middle land part 13 Inner shoulder land part 14 Inner middle land part 20 Horizontal groove 23 Outer middle lateral groove To Outer tread end Ti Inner tread end

Claims (11)

A tire with a tread that is oriented to be mounted on a vehicle.
The tread portion is divided into an outer tread end located on the outside of the vehicle when mounted on the vehicle, an inner tread end located on the inside of the vehicle when mounted on the vehicle, a plurality of main grooves continuously extending in the tire circumferential direction, and the main groove. Including multiple treads
The land portion includes an outer shoulder land portion arranged on the outermost tread end side, an outer middle land portion adjacent to the outer shoulder land portion, and an inner shoulder land portion arranged on the innermost tread end side. , Including the inner middle tread adjacent to the inner shoulder tread,
The main groove includes an outer shoulder main groove extending between the outer shoulder land portion and the outer middle land portion and having the smallest groove width among the plurality of main grooves.
Each of the outer shoulder land portion, the inner shoulder land portion, and the inner middle land portion is provided with a plurality of lateral grooves extending in the tire axial direction.
The outer middle land portion is provided with a plurality of outer middle lateral grooves extending from the outer tread end side edge of the outer middle land portion toward the inner tread end side and interrupting within the outer middle land portion.
Each of the outer middle lateral grooves is inclined with respect to the tire axial direction at an angle larger than that of each of the plurality of lateral grooves .
The outer middle lateral groove includes a first groove portion extending at a constant depth and a second groove portion whose depth gradually decreases toward the inner tread end side.
tire. The tire according to claim 1, wherein the first groove portion communicates with the outer shoulder main groove. The tire according to claim 1 or 2, wherein the second groove portion includes a portion having a depth larger than that of the first groove portion. A tire with a tread that is oriented to be mounted on a vehicle.
The tread portion is divided into an outer tread end located on the outside of the vehicle when mounted on the vehicle, an inner tread end located on the inside of the vehicle when mounted on the vehicle, a plurality of main grooves continuously extending in the tire circumferential direction, and the main groove. Including multiple treads
The land portion includes an outer shoulder land portion arranged on the outermost tread end side, an outer middle land portion adjacent to the outer shoulder land portion, and an inner shoulder land portion arranged on the innermost tread end side. , Including the inner middle tread adjacent to the inner shoulder tread,
The main groove includes an outer shoulder main groove extending between the outer shoulder land portion and the outer middle land portion and having the smallest groove width among the plurality of main grooves.
Each of the outer shoulder land portion, the inner shoulder land portion, and the inner middle land portion is provided with a plurality of lateral grooves extending in the tire axial direction.
The outer middle land portion is provided with a plurality of outer middle lateral grooves extending from the outer tread end side edge of the outer middle land portion toward the inner tread end side and interrupting within the outer middle land portion.
Each of the outer middle lateral grooves is inclined with respect to the tire axial direction at an angle larger than that of each of the plurality of lateral grooves.
The length of the outer middle lateral groove in the tire axial direction is 0.50 to 0.80 times the width of the outer middle lateral groove in the tire axial direction.
tire. A tire with a tread that is oriented to be mounted on a vehicle.
The tread portion is divided into an outer tread end located on the outside of the vehicle when mounted on the vehicle, an inner tread end located on the inside of the vehicle when mounted on the vehicle, a plurality of main grooves continuously extending in the tire circumferential direction, and the main groove. Including multiple treads
The land portion includes an outer shoulder land portion arranged on the outermost tread end side, an outer middle land portion adjacent to the outer shoulder land portion, and an inner shoulder land portion arranged on the innermost tread end side. Includes an inner middle tread adjacent to the inner shoulder tread and a crown tread between the outer middle tread and the inner middle tread.
The main groove includes an outer shoulder main groove extending between the outer shoulder land portion and the outer middle land portion and having the smallest groove width among the plurality of main grooves.
Each of the outer shoulder land portion, the inner shoulder land portion, and the inner middle land portion is provided with a plurality of lateral grooves extending in the tire axial direction.
The outer middle land portion is provided with a plurality of outer middle lateral grooves extending from the outer tread end side edge of the outer middle land portion toward the inner tread end side and interrupting within the outer middle land portion.
Each of the outer middle lateral grooves is inclined with respect to the tire axial direction at an angle larger than that of each of the plurality of lateral grooves.
The outer middle lateral groove includes a first groove portion extending at a constant depth and a second groove portion whose depth gradually decreases toward the inner tread end side.
The crown land portion is provided with an inner slot that extends from the inner tread end side edge to the outer tread end side and is interrupted within the crown land portion.
The maximum depth of the inner slot is 1.35 to 1.70 times the depth of the first groove.
tire. A tire with a tread that is oriented to be mounted on a vehicle.
The tread portion is divided into an outer tread end located on the outside of the vehicle when mounted on the vehicle, an inner tread end located on the inside of the vehicle when mounted on the vehicle, a plurality of main grooves continuously extending in the tire circumferential direction, and the main groove. Including multiple treads
The land portion includes an outer shoulder land portion arranged on the outermost tread end side, an outer middle land portion adjacent to the outer shoulder land portion, and an inner shoulder land portion arranged on the innermost tread end side. Includes an inner middle tread adjacent to the inner shoulder tread and a crown tread between the outer middle tread and the inner middle tread.
The main groove includes an outer shoulder main groove extending between the outer shoulder land portion and the outer middle land portion and having the smallest groove width among the plurality of main grooves.
Each of the outer shoulder land portion, the inner shoulder land portion, and the inner middle land portion is provided with a plurality of lateral grooves extending in the tire axial direction.
The outer middle land portion is provided with a plurality of outer middle lateral grooves extending from the outer tread end side edge of the outer middle land portion toward the inner tread end side and interrupting within the outer middle land portion.
Each of the outer middle lateral grooves is inclined with respect to the tire axial direction at an angle larger than that of each of the plurality of lateral grooves.
The crown land portion is provided with an inner slot that extends from the inner tread end side edge to the outer tread end side and is interrupted within the crown land portion.
The length of the inner slot in the tire axial direction is 0.30 to 0.50 times the width of the crown land portion in the tire axial direction.
tire. A tire with a tread that is oriented to be mounted on a vehicle.
The tread portion is divided into an outer tread end located on the outside of the vehicle when mounted on the vehicle, an inner tread end located on the inside of the vehicle when mounted on the vehicle, a plurality of main grooves continuously extending in the tire circumferential direction, and the main groove. Including multiple treads
The land portion includes an outer shoulder land portion arranged on the outermost tread end side, an outer middle land portion adjacent to the outer shoulder land portion, and an inner shoulder land portion arranged on the innermost tread end side. Includes an inner middle tread adjacent to the inner shoulder tread and a crown tread between the outer middle tread and the inner middle tread.
The main groove includes an outer shoulder main groove extending between the outer shoulder land portion and the outer middle land portion and having the smallest groove width among the plurality of main grooves.
Each of the outer shoulder land portion, the inner shoulder land portion, and the inner middle land portion is provided with a plurality of lateral grooves extending in the tire axial direction.
The outer middle land portion is provided with a plurality of outer middle lateral grooves extending from the outer tread end side edge of the outer middle land portion toward the inner tread end side and interrupting within the outer middle land portion.
Each of the outer middle lateral grooves is inclined with respect to the tire axial direction at an angle larger than that of each of the plurality of lateral grooves.
The crown land portion is provided with an inner slot that extends from the inner tread end side edge to the outer tread end side and is interrupted within the crown land portion.
The transverse groove includes an inner middle transverse groove that crosses the inner middle land portion.
The inner middle lateral groove is smoothly continuous with the inner slot via the main groove.
The maximum angle of the inner middle lateral groove with respect to the tire axial direction is 0.20 to 0.30 times the angle of the outer middle lateral groove with respect to the tire axial direction.
tire. The lateral groove includes an inner shoulder lateral groove that crosses the inner shoulder land portion.
The tire according to claim 7, wherein the inner shoulder lateral groove is smoothly continuous with the inner middle lateral groove via the main groove. The tire according to claim 8, wherein the maximum angle of the inner shoulder lateral groove with respect to the tire axial direction is smaller than the maximum angle of the inner middle lateral groove with respect to the tire axial direction. A tire with a tread that is oriented to be mounted on a vehicle.
The tread portion is divided into an outer tread end located on the outside of the vehicle when mounted on the vehicle, an inner tread end located on the inside of the vehicle when mounted on the vehicle, a plurality of main grooves continuously extending in the tire circumferential direction, and the main groove. Including multiple treads
The tread portion includes an outer tread portion between the outer tread end and the tire equator and an inner tread portion between the inner tread end and the tire equator.
The land portion includes an outer shoulder land portion arranged on the outermost tread end side, an outer middle land portion adjacent to the outer shoulder land portion, and an inner shoulder land portion arranged on the innermost tread end side. , Including the inner middle tread adjacent to the inner shoulder tread,
The main groove includes an outer shoulder main groove extending between the outer shoulder land portion and the outer middle land portion and having the smallest groove width among the plurality of main grooves.
Each of the outer shoulder land portion, the inner shoulder land portion, and the inner middle land portion is provided with a plurality of lateral grooves extending in the tire axial direction.
The outer middle land portion is provided with a plurality of outer middle lateral grooves extending from the outer tread end side edge of the outer middle land portion toward the inner tread end side and interrupting within the outer middle land portion.
Each of the outer middle lateral grooves is inclined with respect to the tire axial direction at an angle larger than that of each of the plurality of lateral grooves.
The outer tread portion has a larger land ratio than the inner tread portion.
tire. The tire according to any one of claims 1 to 10, wherein the groove width of the outer shoulder main groove is 0.50 to 0.65 times the maximum groove width among the plurality of main grooves.

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