JP6880868B2 - tire - Google Patents

Description

The present invention relates to a tire capable of exhibiting excellent steering stability while maintaining wet performance.

For example, Patent Document 1 below proposes a tire in which a plurality of sipes are provided on a land portion of a crown arranged in a central portion of a tread portion. The sipe can increase the frictional force against the wet road surface by its edge and contribute to the improvement of the wet performance.

However, the sipe of Patent Document 1 includes a fully open sipe that completely crosses the land portion of the crown. Full open sipe tended to reduce the rigidity of the land part of the crown and thus the steering stability. Therefore, there is room for further improvement in achieving both wet performance and steering stability.

Japanese Unexamined Patent Publication No. 2016-013820

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 steering stability while maintaining wet performance.

The present invention is a tire having a tread portion, and the tread portion has two crowns by one crown main groove extending in the tire circumferential direction and one shoulder main groove arranged on each side thereof. It is divided into a land part and two shoulder land parts, and each of the two crown land parts is provided with a plurality of sipes having a width of less than 1.5 mm, and each of the two crown land parts. The sipe is only a semi-open sipe having one end communicating with the main groove and the other end terminating in the land portion, and each of the two crown land portions of the sipe is relative to the tire axial direction. And tilted in the same direction.

In the tire of the present invention, it is desirable that the two crown land portions are not provided with grooves having a width of 3 mm or more.

In the tire of the present invention, the tread portion is designated to be mounted on the vehicle, and the two crown land portions are the outer crown land portion and the inner side of the outer crown land portion located inside the vehicle when mounted on the vehicle. The semi-open sipe provided on the outer crown land portion, including the crown land portion, has a plurality of first crown sipes having one end communicating with the shoulder main groove and one end communicating with the crown main groove. The semi-open sipe including a plurality of second crown sipes and provided on the land portion of the inner crown includes a plurality of third crown sipes having one end communicating with the shoulder main groove and the one end having the crown main groove. It is desirable to include a plurality of fourth crown sipes communicating with.

In the tire of the present invention, the shortest distance L1 in the tire circumferential direction between the other end of the first crown sipe and the other end of the second crown sipe is the other end of the third crown sipe and the first. 4 It is desirable that the distance between the crown sipe and the other end of the crown sipe is larger than the shortest distance L2 in the tire circumferential direction.

In the tire of the present invention, the inner crown land portion has a shallow crown groove having a depth of less than 2 mm and connecting the other end of the third crown sipe and the other end of the fourth crown sipe. It is desirable that it is provided.

In the tire of the present invention, it is desirable that the crown shallow groove is inclined in the direction opposite to each sipe with respect to the tire axial direction.

In the tire of the present invention, it is desirable that the fourth crown sipe extends smoothly through the crown main groove so as to be smoothly continuous with the second crown sipe.

In the tire of the present invention, the shoulder land portion includes an outer shoulder land portion located outside the vehicle of the outer crown land portion when mounted on a vehicle, and one end of the outer shoulder land portion communicates with the shoulder main groove. It is desirable that a plurality of outer shoulder lateral grooves are provided, and the outer shoulder lateral grooves extend smoothly through the shoulder main groove so as to be smoothly continuous with the first crown sipe.

In the tire of the present invention, the shoulder land portion includes an inner shoulder land portion located inside the vehicle of the inner crown land portion when mounted on the vehicle, and one end of the inner shoulder land portion communicates with the shoulder main groove. It is desirable that a plurality of inner shoulder sipes are provided, and the inner shoulder sipe extends smoothly through the shoulder main groove so as to be smoothly continuous with the third crown sipe.

In the tire of the present invention, it is desirable that each of the sipes is bent.

In the tire of the present invention, each of the sipes extends from one end to the other end, which is continuous with the first portion and is inclined at a larger angle with respect to the tire axial direction than the first portion. Is desirable.

In the tire of the present invention, it is desirable that one of the two crown land portions is provided with a circumferential shallow groove having a depth of less than 2.0 mm and extending continuously in the tire circumferential direction.

The tread portion of the tire of the present invention has two crown land portions and two shoulder land portions by one crown main groove extending in the tire circumferential direction and one shoulder main groove arranged on each side thereof. It is divided into. A plurality of sipes with a width of less than 1.5 mm are provided on each of the two crown land parts.

In the tire of the present invention, each sipe of the two crown land portions is only a semi-open sipe having one end communicating with the main groove and the other end being terminated in the land portion. Such a semi-open sipe helps maintain the rigidity of the land area of the crown and provides excellent steering stability.

In the tire of the present invention, each of the two crown land sipe is inclined in the same direction with respect to the tire axial direction. As a result, when the land portion of the crown touches the ground on a wet road surface, the sipes can cooperate to guide the water on the road surface in one direction in the tire axial direction. Therefore, the land part of the crown can easily push water away smoothly, and thus the wet performance is maintained.

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 crown land part and the inner crown land part of FIG. FIG. 2 is a sectional view taken along line AA of FIG. It is an enlarged view of the outer crown land part of FIG. It is an enlarged view of the land part of the inner crown of FIG. It is an enlarged view of the outer crown land part and the inner crown land part of another embodiment of this invention. It is an enlarged view of the outer shoulder land part of FIG. FIG. 7 is a cross-sectional view taken along the line BB of FIG. It is an enlarged view of the land part of the inner shoulder of FIG. It is a development view of the tread part of the tire of the comparative example 1. FIG. It is a development view of the tread part of the tire of the comparative example 2. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a developed view of a tread portion 2 of a tire 1 showing an embodiment of the present invention. The tire 1 of the present embodiment 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 invention has 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 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 orientation 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 the 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 JATMA, "Design Rim" for TRA, and ETRTO. If there is, it is "Measuring Rim".

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

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

The tread portion 2 of the present embodiment is provided with, for example, a main groove that extends continuously in the tire circumferential direction. The main groove includes one crown main groove 3 and shoulder main grooves 4 and 5 arranged on both sides thereof. The crown main groove 3 of the present embodiment is provided, for example, on the tire equator C. The shoulder main grooves 4 and 5 are, for example, the outer shoulder main groove 4 arranged between the tire equator C and the outer tread end To, and the inner shoulder main groove 4 arranged between the tire equator C and the inner tread end Ti. Includes a groove 5. In a preferred embodiment, each of the main grooves 3 to 5 extends linearly in the tire circumferential direction.

For the outer shoulder main groove 4 and the inner shoulder main groove 5, for example, it is desirable that the distance L3 from the tire equator C to the groove center line is 0.20 to 0.30 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 crown main groove 3, the outer shoulder main groove 4, and the inner shoulder main groove 5 have, for example, groove widths W1a, W1b, and W1c that are 6 to 9% of the tread width TW. It is desirable that the total groove widths W1a + W1b + W1c of each of the main grooves 3 to 5 is, for example, 22 to 25% of the tread width TW. As a result, wet performance and steering stability are well-balanced.

In a more desirable embodiment, the groove width W1a of the crown main groove 3 is larger than the groove width W1b of the outer shoulder main groove 4. The groove width W1c of the inner shoulder main groove 5 is larger than the groove width W1a of the crown main groove 3. In other words, the groove width of each of the main grooves 3 to 5 is set so as to increase toward the inner tread end Ti side. As a result, excellent drainage can be exhibited in the region between the tire equator C and the inner tread end Ti. Further, the rigidity of the region between the tire equator C and the outer tread end To is increased, and excellent steering stability can be obtained.

The tread portion 2 is divided into two crown land portions 6 and two shoulder land portions 7 by the above-mentioned main grooves 3 to 5. The crown land portion 6 of the present embodiment includes, for example, an outer crown land portion 11 and an inner crown land portion 12. The outer crown land portion 11 is divided between the crown main groove 3 and the outer shoulder main groove 4. The outer crown land portion 11 is located outside the vehicle with respect to the tire equator C when the vehicle is mounted. The inner crown land portion 12 is divided between the crown main groove 3 and the inner shoulder main groove 5. The inner crown land portion 12 is located inside the vehicle of the outer crown land portion 11 when mounted on the vehicle.

The shoulder land portion 7 of the present embodiment includes, for example, an outer shoulder land portion 13 and an inner shoulder land portion 14. The outer shoulder land portion 13 is divided into the outer side of the outer shoulder main groove 4 in the tire axial direction. The inner shoulder land portion 14 is divided into the outer side of the inner shoulder main groove 5 in the tire axial direction.

FIG. 2 shows an enlarged view of the outer crown land portion 11 and the inner crown land portion 12. As shown in FIG. 2, a plurality of sipes 15 are provided on the outer crown land portion 11 and the inner crown land portion 12, respectively. In the present specification, the sipe 15 is defined as a notch having a width of less than 1.5 mm.

FIG. 3 shows a sectional view taken along line AA of the sipe 15. As shown in FIG. 3, the sipe 15 of the present embodiment includes, for example, an aspect extending from the bottom of a shallow groove 16 having a depth d1 of less than 2.0 mm. However, the sipe 15 is not limited to such an aspect, and may extend from the tread surface of the land portion as shown by a virtual line. The depth d2 of the sipe 15 from the land tread is preferably 5.0 to 7.0 mm, for example. It is desirable that the shallow groove 16 of the present embodiment has an opening width W2 of 2.0 to 5.0 mm, for example, on the tread surface of the land portion.

As shown in FIG. 2, each sipe 15 provided on the outer crown land portion 11 and the inner crown land portion 12 is a semi-open sipe having one end communicating with the main groove and the other end being terminated in the land portion. There are only 18. Such a semi-open sipe 18 maintains the rigidity of the crown land portions 11 and 12 and helps to exhibit excellent steering stability.

Each sipe 15 is inclined in the same direction with respect to the tire axial direction. In each figure of the present specification, each sipe 15 is inclined upward to the right. As a result, when the crown land portions 11 and 12 touch the ground on a wet road surface, the sipes 15 can cooperate to guide water on the road surface in one direction in the tire axial direction. Therefore, the crown land portions 11 and 12 can easily push water away smoothly, and thus the wet performance is maintained.

In a more desirable embodiment, it is desirable that the outer crown land portion 11 and the inner crown land portion 12 are not provided with a groove having a width of 3 mm or more. As a result, the rigidity of each of the crown land portions 11 and 12 is increased, and excellent steering stability can be exhibited. The “groove with a width of 3 mm or more” means a groove having a distance between the pair of groove walls of 3 mm or more and a depth of 2 mm or more, and the shallow groove 16 is excluded.

FIG. 4 shows an enlarged view of the outer crown land portion 11. As shown in FIG. 4, the semi-open sipe 18 provided on the outer crown land portion 11 includes, for example, a plurality of first crown sipe 21 and second crown sipe 22. For example, one end 21a of the first crown sipe 21 communicates with the outer shoulder main groove 4, and the other end 21b terminates in the outer crown land portion 11. The second crown sipe 22 has one end 22a communicating with the crown main groove 3 and the other end 22b ending within the outer crown land portion 11. In the present embodiment, the first crown sipe 21 and the second crown sipe 22 are alternately provided in the tire circumferential direction.

It is desirable that the first crown sipe 21 is inclined at an angle θ1 of 15 to 25 ° with respect to the tire axial direction, for example. Similarly, it is desirable that the second crown sipe 22 is inclined at an angle θ2 of 15 to 25 ° with respect to the tire axial direction, for example. Such a first crown sipe 21 and a second crown sipe 22 can provide a well-balanced frictional force in the tire circumferential direction and the tire axial direction during wet running.

It is desirable that the first crown sipe 21 has, for example, a length L4 that is 0.25 to 0.35 times the width W3 of the outer crown land portion 11. Such a first crown sipe 21 maintains the rigidity of the outer crown land portion 11 on the outer side in the tire axial direction, and is useful for exhibiting excellent steering stability.

It is desirable that the second crown sipe 22 has, for example, a length L5 in the tire axial direction that is larger than that of the first crown sipe 21. It is desirable that the length L5 of the second crown sipe 22 is, for example, 0.70 to 0.80 times the width W3 of the outer crown land portion 11. Such a second crown sipe 22, together with the crown main groove 3, is useful for exhibiting excellent wet performance.

In a preferred embodiment, it is desirable that the second crown sipe 22 overlaps the first crown sipe 21 in the tire axial direction. In other words, the other end 22b of the second crown sipe 22 is located outside the other end 21b of the first crown sipe 21 in the tire axial direction. It is desirable that the overlapping width L6 of the second crown sipe 22 and the first crown sipe 21 in the tire axial direction is, for example, 2.0 to 4.0% of the width W3 of the outer crown land portion 11. Such an arrangement of the crown sipes 21 and 22 helps to improve the wet performance and the steering stability in a well-balanced manner.

It is desirable that the shallow groove 16a connected to the outer side in the tire radial direction of the second crown sipe 22 includes, for example, an inner portion 26 and an outer portion 27 having different opening widths on the tread surface of the land portion. The inner portion 26 extends, for example, in the outer crown land portion 11 with an opening width W4. The outer portion 27 extends from the inner portion 26 to the crown main groove 3, for example, and has an opening width W5 larger than the opening width W4 of the inner portion 26. The ratio W4 / W5 of the opening width W4 of the inner portion 26 to the opening width W5 of the outer portion 27 is preferably, for example, 0.60 to 0.80. As a result, the one end 22a side of the second crown sipe 22 can be opened appropriately, and the wet performance can be improved.

FIG. 5 shows an enlarged view of the inner crown land portion 12. As shown in FIG. 5, the semi-open sipe 18 provided on the inner crown land portion 12 includes, for example, a plurality of third crown sipe 23 and fourth crown sipe 24. In the third crown sipe 23, for example, one end 23a communicates with the inner shoulder main groove 5, and the other end 23b terminates in the inner crown land portion 12. The fourth crown sipe 24 has one end 24a communicating with the crown main groove 3 and the other end 24b ending within the inner crown land portion 12. In the present embodiment, the third crown sipe 23 and the fourth crown sipe 24 are alternately provided in the tire circumferential direction.

The third crown sipe 23 is inclined at an angle θ3 of 15 to 25 ° with respect to the tire axial direction, for example. Such a third crown sipe 23 can provide a well-balanced frictional force in the tire circumferential direction and the tire axial direction during wet running.

It is desirable that the third crown sipe 23 has, for example, a length L7 in the tire axial direction that is 0.40 to 0.50 times the width W6 in the tire axial direction of the inner crown land portion 12. In a preferred embodiment, the length L7 of the third crown sipe 23 is larger than, for example, the length L4 of the first crown sipe 21 (shown in FIG. 4). The length L7 of the third crown sipe 23 is smaller than, for example, the length L5 of the second crown sipe 22 (shown in FIG. 4). Such a third crown sipe 23 can optimize the rigidity distribution of the outer crown land portion 11 and the inner crown land portion 12 and make the progress of wear uniform.

As shown in FIG. 2, it is desirable that the fourth crown sipe 24 extends smoothly, for example, through the crown main groove 3 so as to be smoothly continuous with the second crown sipe 22. In addition, "smoothly continuous" includes at least a mode in which one sipe is virtually extended along its length direction and is connected to the end of the other sipe.

As shown in FIG. 5, the fourth crown sipe 24 is inclined at an angle θ4 of, for example, 15 to 25 ° with respect to the tire axial direction. In a preferred embodiment, the fourth crown sipe 24 is arranged parallel to the third crown sipe 23.

It is desirable that the fourth crown sipe 24 has, for example, a length L8 in the tire axial direction of 0.20 to 0.30 times the width W6 of the inner crown land portion 12. In a preferred embodiment, the length L8 of the fourth crown sipe 24 is smaller than, for example, the length L7 of the third crown sipe 23. Such a fourth crown sipe 24 can maintain the rigidity of the inner crown land portion 12 and enhance the steering stability.

In a more preferred embodiment, the fourth crown sipe 24 and the third crown sipe 23 do not overlap in the tire axial direction. In other words, the other end 24b of the fourth crown sipe 24 is located closer to the tire equator C than the other end 23b of the third crown sipe 23. The tire axial separation width L9 between the other end 24b of the fourth crown sipe 24 and the other end 23b of the third crown sipe 23 is, for example, 0.15 to 0.30 of the width W6 of the inner crown land portion 12. It is desirable to double. Such an arrangement of the third crown sipe 23 and the fourth crown sipe 24 can exhibit excellent steering stability while maintaining wet performance.

As shown in FIG. 2, the shortest distance L1 in the tire circumferential direction between the other end 21b of the first crown sipe 21 and the other end 22b of the second crown sipe 22 is the other end 23b of the third crown sipe 23. It is desirable that the distance between the fourth crown sipe 24 and the other end 24b is larger than the shortest distance L2 in the tire circumferential direction. It is desirable that the shortest distance L1 is, for example, 1.5 to 2.0 times the shortest distance L2. With such an arrangement of each sipe, the rigidity of the outer crown land portion 11 can be made higher than that of the inner crown land portion 12, and in particular, the steering stability at the time of turning can be improved.

As shown in FIG. 5, it is desirable that the inner crown land portion 12 is provided with a crown shallow groove 28. The crown shallow groove 28 is, for example, less than 2 mm in depth and connects between the other end 23b of the third crown sipe 23 and the other end 24b of the fourth crown sipe 24. Such a crown shallow groove 28 can improve wet performance while maintaining the rigidity of the inner crown land portion 12.

The crown shallow groove 28 of the present embodiment is inclined in the direction opposite to each sipe 15 with respect to the tire axial direction, for example. It is desirable that the crown shallow groove 28 is inclined at an angle θ5 of 60 to 80 ° with respect to the tire axial direction, for example. The edge of such a crown shallow groove 28 provides a large frictional force in the tire axial direction, and thus the turning performance during wet running is enhanced.

FIG. 6 shows an example of another embodiment of the outer crown land portion 11 and the inner crown land portion 12. As shown in FIG. 6, in this embodiment, each sipe 15 is bent. Each such sipe 15 can provide frictional forces in multiple directions during wet travel.

Each sipe 15 includes, for example, a first portion 31 and a second portion 32 that differ in angle with respect to the tire axial direction. The first portion 31 extends from, for example, one end on the main groove side. The second portion 32 is connected to the first portion 31, and is inclined at a larger angle with respect to the tire axial direction than the first portion 31, and extends to the other end in the land portion. Each of such sipes 15 can increase the apparent rigidity of the land portion when the sipes walls facing each other are in close contact with each other.

In the shallow groove 16 in which the sipes 15 are connected, for example, it is desirable that the opening width in the first portion 31 is larger than the opening width in the second portion 32. Such a shallow groove 16 can further solidify the wet performance.

It is desirable that one of the outer crown land portion 11 and the inner crown land portion 12 is provided with, for example, a circumferential shallow groove 33 having a depth of less than 2.0 mm and continuously extending in the tire circumferential direction. In the present embodiment, the outer crown land portion 11 is provided with a circumferential shallow groove 33. The circumferential shallow groove 33 can improve the wet performance while maintaining the rigidity of the land portion.

FIG. 7 shows an enlarged view of the outer shoulder land portion 13. As shown in FIG. 7, the outer shoulder land portion 13 is provided with, for example, a plurality of outer shoulder lateral grooves 35 and an outer shoulder sipe 36. In the present embodiment, the outer shoulder lateral groove 35 and the outer shoulder sipe 36 are alternately provided in the tire circumferential direction.

One end of the outer shoulder lateral groove 35 communicates with the outer shoulder main groove 4, for example. In a preferred embodiment, the outer shoulder lateral groove 35 extends from, for example, the outer shoulder main groove 4 to the outer tread end To.

It is desirable that the outer shoulder lateral groove 35 is smoothly curved so that, for example, the angle θ6 with respect to the tire axial direction gradually increases inward in the tire axial direction. The angle θ6 is preferably in the range of, for example, 5 to 20 °. Such an outer shoulder lateral groove 35 can smoothly guide the water in the groove to the outer tread end To side during wet running, and can exhibit further excellent wet performance.

FIG. 8 shows a sectional view taken along line BB of the outer shoulder lateral groove 35. As shown in FIG. 8, it is desirable that the bottom surface of the outer shoulder lateral groove 35 is raised, for example, at the inner end portion 35i in the tire axial direction. It is desirable that the depth d4 of the inner end portion 35i is, for example, 0.50 to 0.60 times the maximum depth d3 of the outer shoulder lateral groove 35. Such an outer shoulder lateral groove 35 can increase the rigidity of the outer shoulder land portion 13 on the inner side in the tire axial direction, and can further improve the steering stability.

As shown in FIG. 1, it is desirable that the outer shoulder lateral groove 35 extends smoothly and continuously with the first crown sipe 21 via, for example, the shoulder main groove 4. Such an outer shoulder lateral groove 35 can enhance the wet performance in cooperation with the first crown sipe 21.

As shown in FIG. 7, the outer shoulder sipe 36 completely crosses, for example, the outer shoulder land portion 13. It is desirable that the outer shoulder sipe 36 is smoothly curved so that, for example, the angle θ7 with respect to the tire axial direction gradually increases inward in the tire axial direction. The angle θ7 is preferably in the range of, for example, 5 to 20 °. In a more preferred embodiment, the outer shoulder sipe 36 extends along the outer shoulder lateral groove 35. Such an outer shoulder sipe 36 can suppress distortion of the ground contact surface of the outer shoulder land portion 13 and suppress uneven wear thereof.

FIG. 9 shows an enlarged view of the inner shoulder land portion 14. As shown in FIG. 9, the inner shoulder land portion 14 is provided with, for example, a plurality of inner shoulder lateral grooves 37 and an inner shoulder sipe 38. In the present embodiment, the inner shoulder lateral groove 37 and the inner shoulder sipe 38 are alternately provided in the tire circumferential direction.

The inner shoulder lateral groove 37 extends inward in the tire axial direction from, for example, the inner tread end Ti and is interrupted in the inner shoulder land portion 14. It is desirable that the inner shoulder lateral groove 37 of the present embodiment has, for example, a length L10 in the tire axial direction that is 0.75 to 0.85 times the width W7 in the tire axial direction of the inner shoulder land portion 14. Such an inner shoulder lateral groove 37 can improve wet performance and steering stability in a well-balanced manner.

In the present embodiment, the region between the inner shoulder lateral groove 37 and the inner shoulder main groove 4 is not provided with a notch such as a sipe. As a result, the rigidity of the inner shoulder land portion 14 on the inner side in the tire axial direction is surely increased.

The inner shoulder lateral groove 37 includes, for example, a first groove portion 41 and a second groove portion 42 having different angles with respect to the tire axial direction. The first groove portion 41 is inclined at an angle θ8 (not shown) of 5 ° or less with respect to the tire axial direction, for example. The second groove portion 42 is bent and extended so as to form a bent groove portion 43 with the first groove portion 41, for example. The angle θ9 of the second groove portion 42 with respect to the tire axial direction is preferably, for example, 10 to 20 °. As a more desirable embodiment, in the first groove portion 41 and the second groove portion 42, for example, the respective groove center lines extend linearly. Such an inner shoulder lateral groove 37 can guide the water in the groove toward the inner tread end Ti side.

It is desirable that the distance L11 in the tire axial direction from the inner tread end Ti to the bent groove portion 43 is, for example, 0.40 to 0.60 times the width W7 of the inner shoulder land portion 14. As a result, the above-mentioned effect can be obtained while suppressing uneven wear of the inner shoulder land portion 14.

As a more desirable embodiment, the second groove portion 42 has a pair of groove edges that are inclined with respect to the tire axial direction and extend linearly, and the groove width between the pair of groove edges gradually decreases inward in the tire axial direction. It is desirable to have. Such a second groove 42 can suppress uneven wear at the inner end of the inner shoulder lateral groove 37.

The inner shoulder sipe 38 has, for example, one end communicating with the inner shoulder main groove 5 and extending to the inner tread end Ti. As shown in FIG. 1, the inner shoulder sipe 38 extends smoothly, for example, through the inner shoulder main groove 5 so as to be smoothly continuous with the third crown sipe 23. As a result, the inner shoulder sipe 38 can be opened more easily, and a high frictional force can be expected against a wet road surface.

As shown in FIG. 9, the inner shoulder sipe 38 includes, for example, a first sipe portion 45 and a second sipe portion 46 having different angles with respect to the tire axial direction. The first sipe portion 45 extends at an angle θ10 (not shown) of 5 ° or less with respect to the tire axial direction, for example. The second sipe portion 46 is bent so as to form a bent sipe portion 47 with the first sipe portion 45, for example. It is desirable that the second sipe portion 46 is inclined at an angle θ11 of 15 to 25 ° with respect to the tire axial direction, for example. As a more desirable embodiment, the first sipe portion 45 and the second sipe portion 46 extend linearly, respectively.

It is desirable that the distance L12 in the tire axial direction from the inner tread end Ti of the present embodiment to the bent sipe portion 47 is, for example, 0.40 to 0.50 times the width W7 of the inner shoulder land portion 14. Such a bent sipe portion 47 helps to suppress distortion of the contact patch at the center of the inner shoulder 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 may be modified to various embodiments.

A size 205 / 55R16 tire having the basic pattern of FIG. 1 was prototyped based on the specifications in Table 1. As Comparative Example 1, as shown in FIG. 10, a tire provided with a fully open sipe on the land part of the crown was prototyped. As Comparative Example 2, as shown in FIG. 11, a tire provided with crown sipes having different inclination directions on the outer crown land portion and the inner crown land portion was prototyped. The wet performance and steering stability of each test tire were tested. The common specifications and test methods for each test tire are as follows.
Mounting rim: 16 x 6.5 JJ
Tire internal pressure: 230kPa
Test vehicle: Front-wheel drive vehicle, displacement 2000cc
Tire mounting position: The all-wheel test method is as follows.

<Wet performance>
The test vehicle traveled on an asphalt road surface having a depth of 5 mm and a length of 20 m and a radius of 100 m, and the lateral acceleration (lateral G) of the front wheels was measured. The result is an average lateral G of a speed of 50 to 80 km / h, and is shown by an index with the value of Comparative Example 1 as 100. The larger the value, the better the wet performance.

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

As a result of the test, it was confirmed that the tires of the examples exhibited excellent steering stability while maintaining wet performance.

2 Tread part 3 Crown main groove 4 Shoulder main groove 6 Crown land part 7 Shoulder land part 15 Sipe 18 Semi-open sipe

Claims (9)

A tire with a tread
The tread portion has two crown lands, which are designated to be mounted on a vehicle and have one crown main groove extending in the tire circumferential direction and one shoulder main groove on each side thereof. It is divided into a part and two shoulder land parts,
A plurality of sipes with a width of less than 1.5 mm are provided on each of the two crown land areas.
Each of the two crown land sipe is only a semi-open sipe whose one end communicates with the main groove and the other end terminates in the land.
Each sipe of the two crown land portion are both Ri Contact inclined in the same direction with respect to the tire axial direction,
The two crown land portions include an outer crown land portion and an inner crown land portion located inside the vehicle of the outer crown land portion when mounted on a vehicle.
The semi-open sipe provided on the outer crown land portion includes a plurality of first crown sipe having one end communicating with the shoulder main groove and a plurality of second crown sipe having one end communicating with the crown main groove. Including
The semi-open sipe provided on the inner crown land portion includes a plurality of third crown sipe having one end communicating with the shoulder main groove and a plurality of fourth crown sipe having one end communicating with the crown main groove. Including
The shortest distance L1 in the tire circumferential direction between the other end of the first crown sipe and the other end of the second crown sipe is the other end of the third crown sipe and the other of the fourth crown sipe. A tire larger than the shortest distance L2 in the tire circumferential direction between the end and the tire. The tire according to claim 1, wherein the two crown land portions are not provided with a groove having a width of 3 mm or more. The inner crown land portion is provided with a shallow crown groove having a depth of less than 2 mm and connecting between the other end of the third crown sipe and the other end of the fourth crown sipe. The tire according to 1 or 2. The tire according to claim 3, wherein the crown shallow groove is inclined in the direction opposite to each sipe with respect to the tire axial direction. A tire with a tread
The tread portion has two crown lands, which are designated to be mounted on a vehicle and have one crown main groove extending in the tire circumferential direction and one shoulder main groove on each side thereof. It is divided into a part and two shoulder land parts,
A plurality of sipes with a width of less than 1.5 mm are provided on each of the two crown land areas.
Each of the two crown land sipe is only a semi-open sipe whose one end communicates with the main groove and the other end terminates in the land.
Each of the sipes on the land of the two crowns is inclined in the same direction with respect to the tire axial direction.
The two crown land portions include an outer crown land portion and an inner crown land portion located inside the vehicle of the outer crown land portion when mounted on a vehicle.
The semi-open sipe provided on the outer crown land portion includes a plurality of first crown sipe having one end communicating with the shoulder main groove and a plurality of second crown sipe having one end communicating with the crown main groove. Including
The semi-open sipe provided on the inner crown land portion includes a plurality of third crown sipe having one end communicating with the shoulder main groove and a plurality of fourth crown sipe having one end communicating with the crown main groove. Including
The fourth crown sipe is a tire extending smoothly and continuously with the second crown sipe through the crown main groove. A tire with a tread
The tread portion has two crown lands, which are designated to be mounted on a vehicle and have one crown main groove extending in the tire circumferential direction and one shoulder main groove on each side thereof. It is divided into a part and two shoulder land parts,
A plurality of sipes with a width of less than 1.5 mm are provided on each of the two crown land areas.
Each of the two crown land sipe is only a semi-open sipe whose one end communicates with the main groove and the other end terminates in the land.
Each of the sipes on the land of the two crowns is inclined in the same direction with respect to the tire axial direction.
The two crown land portions include an outer crown land portion and an inner crown land portion located inside the vehicle of the outer crown land portion when mounted on a vehicle.
The semi-open sipe provided on the outer crown land portion includes a plurality of first crown sipe having one end communicating with the shoulder main groove and a plurality of second crown sipe having one end communicating with the crown main groove. Including
The semi-open sipe provided on the inner crown land portion includes a plurality of third crown sipe having one end communicating with the shoulder main groove and a plurality of fourth crown sipe having one end communicating with the crown main groove. Including
The shoulder land portion includes an outer shoulder land portion located outside the vehicle of the outer crown land portion when mounted on the vehicle.
The outer shoulder land portion is provided with a plurality of outer shoulder lateral grooves having one end communicating with the shoulder main groove.
The outer shoulder lateral groove is a tire that extends smoothly through the shoulder main groove so as to be smoothly continuous with the first crown sipe. A tire with a tread
The tread portion has two crown lands, which are designated to be mounted on a vehicle and have one crown main groove extending in the tire circumferential direction and one shoulder main groove on each side thereof. It is divided into a part and two shoulder land parts,
A plurality of sipes with a width of less than 1.5 mm are provided on each of the two crown land areas.
Each of the two crown land sipe is only a semi-open sipe whose one end communicates with the main groove and the other end terminates in the land.
Each of the sipes on the land of the two crowns is inclined in the same direction with respect to the tire axial direction.
The two crown land portions include an outer crown land portion and an inner crown land portion located inside the vehicle of the outer crown land portion when mounted on a vehicle.
The semi-open sipe provided on the outer crown land portion includes a plurality of first crown sipe having one end communicating with the shoulder main groove and a plurality of second crown sipe having one end communicating with the crown main groove. Including
The semi-open sipe provided on the inner crown land portion includes a plurality of third crown sipe having one end communicating with the shoulder main groove and a plurality of fourth crown sipe having one end communicating with the crown main groove. Including
The shoulder land portion includes an inner shoulder land portion located inside the vehicle of the inner crown land portion when mounted on the vehicle.
The inner shoulder land portion is provided with a plurality of inner shoulder sipes whose one end communicates with the shoulder main groove.
The inner shoulder sipe is a tire that extends smoothly through the shoulder main groove so as to be smoothly continuous with the third crown sipe. A tire with a tread
The tread portion is divided into two crown land portions and two shoulder land portions by one crown main groove extending in the tire circumferential direction and one shoulder main groove arranged on each side thereof. Ori,
A plurality of sipes with a width of less than 1.5 mm are provided on each of the two crown land areas.
Each of the two crown land sipe is only a semi-open sipe whose one end communicates with the main groove and the other end terminates in the land.
Each of the sipes on the land of the two crowns is inclined in the same direction with respect to the tire axial direction.
Each of the above sipes is bent
A tire having a depth of less than 2.0 mm and a circumferential shallow groove extending continuously in the tire circumferential direction on one of the two crown land portions. Each sipe includes a first portion extending from one end and a second portion connected to the first portion and inclined at a larger angle with respect to the tire axial direction than the first portion and extending to the other end. The tire according to claim 8.

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