JP6613885B2 - Automobile tires - Google Patents

Description

  The present invention relates to an automobile tire that is particularly suitable as a wet tire for a racing cart.

  Conventionally, various studies have been made on automobile tires in order to improve wet performance. For example, in Patent Document 1 below, the tread portion is formed into a plurality of blocks by forming two pairs of main grooves extending continuously in the tire circumferential direction and a plurality of lateral grooves extending in the tire axial direction on the tread portion. A segmented pneumatic tire is disclosed.

JP 2011-189846 A

  However, in the pneumatic tire described in Patent Document 1, the lateral groove formed in the crown land portion in the vicinity of the tire equator has insufficient rigidity in the tire circumferential direction at the crown land portion, and braking performance and traction performance. May get worse. In addition, the wear resistance performance of the crown land portion may be reduced.

  The present invention has been devised in view of the above circumstances, and provides a tire for an automobile that can improve braking performance, traction performance and wear resistance performance without sacrificing wet performance. The main purpose is to provide.

  The present invention relates to a four-wheeled vehicle tire having a tread portion, wherein the tread portion includes a first tread half portion from a tire equator to a first tread ground end, and a tire equator to the first tread ground end. A first tread main groove extending continuously in the tire circumferential direction is provided in the first tread half, and the second tread half is a tread ground end opposite to the second tread ground end. By providing the second crown main groove extending continuously in the tire circumferential direction in the second tread half portion, the tread portion has a crown land between the first crown main groove and the second crown main groove. A first shoulder land portion between the first crown main groove and the first tread grounding end, and a second shoulder land portion between the second crown main groove and the second tread grounding end. Divided and said The shoulder land portion is provided with a plurality of first inclined grooves that are inclined with respect to the tire circumferential direction from the tip portion on the first tread grounding end side with respect to the first crown main groove and extend to the first tread grounding end. The second shoulder land portion includes a plurality of slopes extending in a direction opposite to the first inclined groove from the tip portion on the second tread grounding end side with respect to the second crown main groove and extending to the second tread grounding end. The crown land portion is formed in a rib shape continuous in the tire circumferential direction, extends from the first crown main groove toward the tire equator, and has a plurality of ends at the crown land portion. And a plurality of second crown slots extending from the second crown main groove toward the tire equator and terminating in the crown land portion.

  In the automobile tire according to the present invention, it is preferable that the first crown slot and the second crown slot are alternately formed in a tire circumferential direction.

  In the automobile tire according to the present invention, the first shoulder land portion includes a first narrow groove extending from an edge of the first inclined groove on the first tread grounding end side toward the tire equator. It is preferable that the second shoulder land portion is provided with a second narrow groove extending from the edge of the second inclined groove on the second tread grounding end side toward the tire equator.

  In the automobile tire according to the present invention, preferably, the first narrow groove communicates with the first crown main groove, and the second narrow groove communicates with the second crown main groove.

  In the automobile tire according to the present invention, the first narrow groove is disposed on the same axial line as the first crown slot, and the second narrow groove is in the same axial direction as the second crown slot. It is desirable to arrange on a line.

  In the automobile tire according to the present invention, a third narrow groove that connects the first crown main groove and the first tread grounding end is provided between the first narrow grooves adjacent in the tire circumferential direction. It is desirable that a fourth narrow groove that connects the second crown main groove and the second tread grounding end is provided between the second narrow grooves provided adjacent to each other in the tire circumferential direction.

  In the automobile tire according to the present invention, the crown land portion has a land portion in a region facing the third narrow groove via the first crown main groove, and the second crown main groove is formed. It is desirable to have a land portion in a region facing the fourth narrow groove.

  In the automobile tire according to the present invention, the first narrow groove terminates at a groove edge on the first tread grounding end side of the first inclined groove, and the second narrow groove includes the second narrow groove. It is desirable to terminate at the groove edge on the second tread grounding end side of the inclined groove.

  In the automobile tire according to the present invention, a fifth narrow groove extending from the first inclined groove toward the tire equator is provided between the first narrow grooves adjacent to each other in the tire circumferential direction. It is desirable that a sixth narrow groove extending from the second inclined groove toward the tire equator is provided between the second narrow grooves adjacent in the circumferential direction.

  In the automobile tire according to the present invention, the length of the crown land portion in the tire axial direction is a length in the tire axial direction from the first tread grounding end to the second tread grounding end. It is desirable to be 5% to 20% of the above.

  In the automobile tire according to the present invention, a first lateral groove that is formed on an outer side in the tire axial direction than the first tread grounding end and communicates with the first inclined groove, and a second tread grounding end. It is desirable to further have a second lateral groove formed outside the tire axial direction and communicating with the second inclined groove.

  In the automobile tire according to the present invention, a third lateral groove formed outside the first tread ground end in the tire axial direction and communicating with the third narrow groove, and a second tread ground end It is desirable to further have a fourth lateral groove formed outside the tire axial direction and communicating with the fourth narrow groove.

  The automobile tire according to the present invention is provided with the first crown main groove in the first tread half and the second crown main groove in the second tread half so that the drainage performance in the crown region is improved. Increased wet performance. Furthermore, since the tip end portion of the first inclined groove is disposed in the first shoulder land portion, the rigidity of the first shoulder land portion in the vicinity of the first crown main groove is enhanced. Similarly, since the tip of the second inclined groove is disposed on the second shoulder land portion, the rigidity of the second shoulder land portion in the vicinity of the second crown main groove is enhanced.

  Further, the first crown slot and the second crown slot provided in the crown land portion enhance the drainage performance in the crown region and improve the wet performance. Furthermore, the end of the first crown slot and the end of the second crown slot are arranged in the crown land portion, and the crown land portion is formed in a rib shape continuous in the tire circumferential direction. As a result, the braking performance, traction performance, and wear resistance performance are improved.

It is an expanded view of the tread part of one embodiment of the tire for automobiles of the present invention. It is the AA line cross-sectional shape of the tread part of FIG. FIG. 2 is an enlarged development view of a first tread half portion of the tread portion of FIG. 1. FIG. 3 is an enlarged development view of a second tread half portion of the tread portion of FIG. 1. It is an expanded view of the modification of the tread part of FIG. It is an expanded view of another modification of the tread part of FIG. FIG. 10 is a development view of still another modification of the tread portion of FIG. 1.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a development view of a tread portion 2 of a tire for an automobile (the whole is not shown) according to the present embodiment. The automobile tire of the present invention is suitably used as a wet tire for a racing cart, for example. As shown in FIG. 1, the automobile tire according to the present embodiment includes a tread portion 2, a first tread half portion 21 from the tire equator CL to the first tread grounding end TE <b> 1, and a tire equator CL. The first tread grounding end TE1 and the second tread half 22 up to the second tread grounding end TE2 which is the tread grounding end on the opposite side.

  “Tread grounding ends” TE1 and TE2 are regular tires that are assembled in regular rims and filled with regular internal pressure. The regular tires are loaded with regular loads and grounded to a flat surface with a camber angle of 0 degrees. It is determined as the ground contact position on the outermost side in the tire axial direction when the load is applied.

  The “regular rim” is a rim determined 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, ETRTO If so, it is "Measuring Rim".

  “Regular internal pressure” is the air pressure that each standard defines for each tire in the standard system including the standard on which the tire is based. “JAMATA” is the “maximum air pressure”, TRA is the table “TIRE LOAD LIMITS” The maximum value described in "AT VARIOUS COLD INFLATION PRESSURES". If ETRTO, "INFLATION PRESSURE". When the tire is for a passenger car, the normal internal pressure is 180 kPa.

  “Regular load” is a load determined by each standard for each tire in the standard system including the standard on which the tire is based. “JATMA” is “maximum load capacity”, TRA is “TIRE LOAD” The maximum value described in “LIMITS AT VARIOUS COLD INFLATION PRESSURES”, “LOAD CAPACITY” in the case of ETRTO. When the tire is for a passenger car, the load corresponds to 88% of the load.

  In the tire for the front wheel of the racing cart tire, the “first tread grounding end” TE1 and the “second tread grounding end” TE2 are mounted on a rim having a rim width of 4.5 inches, for example, with an air pressure of 100 kPa and a load. It is a tread grounding end measured under a load of 0.45 kN. In the tire for the rear wheel of the racing cart tire, for example, the “first tread ground end” TE1 and the “second tread ground end” TE2 are mounted on a rim having a rim width of 6.5 inches, the air pressure is 100 kPa, and the load It is a tread grounding end measured under a load of 0.65 kN. Hereinafter, in this application, when there is no notice in particular, the dimension of each part of a tire, etc. are the values measured in this state. For example, the tread contact width TW is determined by the distance in the tire axial direction between the first tread contact end TE1 and the second tread contact end TE2.

  The tread portion 2 is provided with a first crown main groove 3 and a second crown main groove 4. The first crown main groove 3 extends continuously through the first tread half 21 in the tire circumferential direction. The second crown main groove 4 extends continuously through the second tread half 22 in the tire circumferential direction.

  The width W3 of the first crown main groove 3 and the width W4 of the second crown main groove 4 are preferably 3% to 25% of the tread ground contact width TW. When the widths W3 and W4 are less than 3% of the tread ground contact width TW, the drainage performance may be affected. When the width W5 exceeds 25% of the tread ground contact width TW, the actual ground contact area of the tread portion 2 is reduced, which may affect grip performance and wear resistance performance. The widths W3 and W4 that are more desirable from the above viewpoint are 6% to 10% of the tread ground contact width TW.

  FIG. 2 shows a cross-sectional shape of the tread portion 2. The depth of the first crown main groove 3 and the second crown main groove 4 is preferably 55% to 85% of the rubber thickness of the tread portion 2. The rubber thickness of the tread portion 2 is the thickness of the rubber formed on the outer side in the tire radial direction of the reinforcing layer formed in the tread portion 2. If the depth is less than 55% of the rubber thickness, the drainage performance may be affected. When the depth exceeds 85% of the rubber thickness, the rigidity of the tread portion 2 is lowered, which may affect grip performance. The depth that is more desirable from the above viewpoint is 65% to 75% of the tread contact width TW of the rubber thickness.

  By providing the first crown main groove 3 and the second crown main groove 4 on both sides of the tire equator CL, the tread portion 2 has a crown land portion between the first crown main groove 3 and the second crown main groove 4. 23, a first shoulder land portion 25 between the first crown main groove 3 and the first tread grounding end TE1, and a second shoulder land portion between the second crown main groove 4 and the second tread grounding end TE2. 26.

  The width W23 of the crown land portion 23 is desirably 5% to 20% of the tread ground contact width TW. When the width W23 is less than 5% of the tread ground contact width TW, the rigidity of the crown land portion 23 in the tire axial direction is insufficient, which may affect cornering performance. Further, the rubber volume of the crown land portion 23 is insufficient, which may affect the wear resistance performance. When the width W23 exceeds 20% of the tread ground contact width TW, the drainage performance may be affected. The width W23 that is more desirable from the above viewpoint is 8% to 12% of the tread ground contact width TW.

  A plurality of first inclined grooves 5 are provided in the first shoulder land portion 25. On the other hand, the second shoulder land portion 26 is provided with a plurality of second inclined grooves 6. The first inclined groove 5 and the second inclined groove 6 are inclined in directions opposite to each other with respect to the tire circumferential direction. The first inclined groove 5 and the second inclined groove 6 define a rotation direction R of the tire for an automobile.

  The second inclined grooves 6 are arranged so as to be shifted from the first inclined grooves 5 by the length of ½ pitch of the first inclined grooves 5 in the tire circumferential direction. Thereby, the distribution of rigidity of the tread portion 2 in the tire circumferential direction is made uniform, and the steering stability performance is improved.

  FIG. 3 shows the crown land portion 23 and the first shoulder land portion 25. The first inclined groove 5 is inclined with respect to the tire circumferential direction from the front end portion 5a on the first tread grounding end TE1 side with respect to the first crown main groove 3, and extends to the first tread grounding end TE1. The drainage performance of the first shoulder land portion 25 is enhanced by the first inclined groove 5 having such a shape, and the rigidity of the first shoulder land portion 25 in the vicinity of the first crown main groove 3 is enhanced, so that braking is performed. Performance, traction performance and wear resistance are improved.

  The width W5 of the first inclined groove 5 is desirably 3% to 25% of the tread ground contact width TW. When the width W5 is less than 3% of the tread ground contact width TW, the drainage performance may be affected. When the width W5 exceeds 25% of the tread ground contact width TW, the actual ground contact area of the first shoulder land portion 25 may be reduced, which may affect grip performance and wear resistance performance.

  The depth of the first inclined groove 5 is desirably 55% to 85% of the rubber thickness of the tread portion 2. If the depth is less than 55% of the rubber thickness, the drainage performance may be affected. When the depth exceeds 85% of the rubber thickness, the rigidity of the first shoulder land portion 25 may be reduced, and the grip performance may be affected. The depth more desirable from the above viewpoint is 65% to 75% of the rubber thickness.

  The angle α1 of the first inclined groove 5 with respect to the tire circumferential direction is preferably 10 ° to 30 °. The angle α1 is defined, for example, as an angle formed by the center line of the first inclined groove 5 and the tire circumferential direction (hereinafter, the same applies to the groove angle). When the angle α1 is less than 10 °, the wear resistance may be affected. When the angle α1 exceeds 30 °, the drainage performance may be affected. Further, by setting the angle α1 in the range of 10 ° to 30 °, the rigidity in the tire axial direction of the first shoulder land portion 25 is enhanced, and the grip performance is improved.

  FIG. 4 shows the crown land portion 23 and the second shoulder land portion 26. The second inclined groove 6 is inclined with respect to the tire circumferential direction from the tip portion 6a on the second tread grounding end TE2 side with respect to the second crown main groove 4, and extends to the second tread grounding end TE2. The drainage performance of the second shoulder land portion 26 is enhanced by the second inclined groove 6 having such a shape, and the rigidity of the second shoulder land portion 26 in the vicinity of the second crown main groove 4 is enhanced. Performance, traction performance and wear resistance are improved.

  The width W6, depth, and angle α2 with respect to the tire circumferential direction of the second inclined groove 6 are the same as those of the first inclined groove 5.

  As shown in FIGS. 1 to 4, the crown land portion 23 is formed in a rib shape continuous in the tire circumferential direction. Therefore, the rigidity of the crown land portion in the tire circumferential direction is increased, and the braking performance, traction performance, and wear resistance performance are improved. Further, since the crown land portion 23 is continuous in the tire circumferential direction, the distribution of the contact pressure is made uniform, and the wear resistance performance is improved.

  The crown land portion 23 is provided with a plurality of first crown slots 7 and a plurality of second crown slots 8. The first crown slot 7 and the second crown slot 8 enhance the drainage performance of the crown land portion 23. When the load is applied to the tire for the automobile by the first crown slot 7 and the second crown slot 8, the crown land portion 23 is appropriately bent and the ground contact area is increased.

  The width W7 of the first crown slot 7 and the width W8 of the second crown slot 8 are preferably 1% to 5% of the tread ground contact width TW. When the widths W7 and W8 are less than 1% of the tread ground contact width TW, the drainage performance may be affected. When the widths W7 and W8 exceed 5% of the tread ground contact width TW, the actual ground contact area of the crown land portion 23 may be reduced, which may affect grip performance and wear resistance performance.

  The depth of the first crown slot 7 and the second crown slot 8 is preferably 20% to 85% of the rubber thickness of the tread portion 2. If the depth is less than 20% of the rubber thickness, the drainage performance may be affected. When the depth exceeds 85% of the rubber thickness, the rigidity of the crown land portion 23 is lowered, which may affect the grip performance. The depth more desirable from the above viewpoint is 35% to 45% of the rubber thickness.

  The angle of the first crown slot 7 and the second crown slot 8 with respect to the tire axial direction is preferably 45 ° or less. When the angle exceeds 45 °, the rigidity of the crown land portion 23 in the tire axial direction is insufficient, which may affect grip performance and wear resistance performance. A more desirable angle is 0 °. That is, it is desirable that the first crown slot 7 and the second crown slot 8 extend toward the tire equator CL along the tire axial direction. “Along the tire axial direction” means substantially parallel to the tire axial direction.

  The first crown slot 7 extends from the first crown main groove 3 toward the tire equator CL, and has a terminal end 7 a at the crown land portion 23. On the other hand, the second crown slot 8 extends from the second crown main groove 4 toward the tire equator CL and has a terminal end 8 a at the crown land portion 23. With the first crown slot 7 and the second crown slot 8 having such a shape, the continuity of the crown land portion 23 in the tire circumferential direction is maintained, and good traction performance and wear resistance performance can be obtained.

  In the present embodiment, the terminal end 7a of the first crown slot 7 and the terminal end 8a of the second crown slot are arranged on the tire equator CL. Thereby, sufficient rigidity in the tire circumferential direction is obtained at the crown land portion 23.

  The first crown slot 7 and the second crown slot 8 are alternately formed in the tire circumferential direction. Thereby, the rigidity distribution of the crown land portion 23 is made uniform, and the braking performance, traction performance, and uneven wear resistance are improved. In the present embodiment, the second crown slot 8 and the first crown slot 7 are arranged so as to be shifted from the first crown slot 7 by the length of ½ pitch of the first crown slot 7 in the tire circumferential direction. Thereby, the rigidity distribution of the crown land portion 23 can be made more uniform.

  A plurality of first narrow grooves 9 are provided in the first shoulder land portion 25. The first narrow groove 9 extends from the edge 5b of the first inclined groove 5 on the first tread grounding end TE1 side toward the tire equator CL. The first narrow groove 9 enhances the drainage performance of the first shoulder land portion 25 and improves the wet performance.

  The width W9 of the first narrow groove 9 is desirably 1% to 5% of the tread ground contact width TW. When the width W9 is less than 1% of the tread ground contact width TW, the drainage performance may be affected. When the width W9 exceeds 5% of the tread ground contact width TW, the actual ground contact area of the first shoulder land portion 25 may be reduced, which may affect grip performance and wear resistance performance.

  The depth of the first narrow groove 9 is desirably 20% to 85% of the rubber thickness of the tread portion 2. If the depth is less than 20% of the rubber thickness, the drainage performance may be affected. When the depth exceeds 85% of the rubber thickness, the rigidity of the first shoulder land portion 25 may be reduced, and the grip performance may be affected. The depth more desirable from the above viewpoint is 35% to 45% of the rubber thickness.

  The depth of the first narrow groove 9 may be different in the tire axial direction. In the present embodiment, on the tire equator CL side with respect to the first inclined groove 5, the depth of the first narrow groove 9 is smaller than that of the first inclined groove 5, and the first tread ground contact end TE <b> 1 than the first inclined groove 5. On the side, the depth of the first narrow groove 9 is equal to that of the first inclined groove 5.

  The angle of the first narrow groove 9 with respect to the tire axial direction is preferably 45 ° or less. When the angle exceeds 45 °, the rigidity of the first shoulder land portion 25 in the tire axial direction is insufficient, which may affect grip performance and wear resistance performance. A more desirable angle is 0 °. That is, it is desirable that the first narrow groove 9 extends in the tire axial direction toward the tire equator CL.

  In the present embodiment, the first narrow groove 9 communicates with the first crown main groove 3. By such a first narrow groove 9, the first shoulder land portion 25 is divided into a plurality of middle blocks 27 and a plurality of shoulder blocks 29. The middle block 27 is partitioned by the first crown main groove 3, the first inclined groove 5, and a pair of first narrow grooves 9 adjacent in the circumferential direction. The shoulder block 29 is defined by the first inclined groove 5, the first tread grounding end TE <b> 1, and the first narrow groove 9.

  The first narrow groove 9 optimizes the rigidity of the first shoulder land portion 25 and improves the warming performance of the first tread half portion 21. The end of the shoulder block 29 on the tire equator CL side is formed in a wedge-like shape. With such a shoulder block 29, the drainage performance of the first inclined groove 5 and the first narrow groove 9 is enhanced.

  The first narrow groove 9 is arranged on the same axial direction line as the first crown slot 7. Thereby, when a load is applied to the tire for the automobile, the crown land portion 23 and the first shoulder land portion 25 are appropriately bent, and the contact area is increased.

  A plurality of second narrow grooves 10 are provided in the second shoulder land portion 26. The second narrow groove 10 extends from the edge 6b of the second inclined groove 6 on the second tread grounding end TE2 side toward the tire equator CL. The drainage performance of the second shoulder land portion 26 is enhanced by the second narrow groove 10, and the wet performance is improved.

  The width W10, depth, and angle with respect to the tire axial direction of the second narrow groove 10 are the same as those of the first narrow groove 9.

  In the present embodiment, the second narrow groove 10 communicates with the second crown main groove 4. By the second narrow groove 10, the second shoulder land portion 26 is divided into a plurality of middle blocks 28 and a plurality of shoulder blocks 30. The middle block 28 is partitioned by the second crown main groove 4, the second inclined groove 6, and a pair of second narrow grooves 10 adjacent in the circumferential direction. The shoulder block 30 is defined by the second inclined groove 6, the second tread grounding end TE <b> 2, and the second narrow groove 10.

  The second narrow groove 10 optimizes the rigidity of the second shoulder land portion 26 and improves the warming performance of the second tread half portion 22. The end of the shoulder block 30 on the tire equator CL side is formed in a wedge-like shape. By such a shoulder block 30, the drainage performance of the second inclined groove 6 and the second narrow groove 10 is enhanced.

  The second narrow groove 10 is disposed on the same axial direction line as the second crown slot 8. As a result, when a load is applied to the automobile tire, the crown land portion 23 and the second shoulder land portion 26 are appropriately bent, and the ground contact area is increased.

  A third narrow groove 11 is provided between the first narrow grooves 9 adjacent in the tire circumferential direction. The third narrow groove 11 connects the first crown main groove 3 and the first tread grounding end TE1. The drainage performance of the first shoulder land portion 25 is further enhanced by the third narrow groove 11, and the wet performance is improved.

  The width W11 of the third narrow groove 11 is desirably 1% to 5% of the tread ground contact width TW. When the width W11 is less than 1% of the tread contact width TW, the drainage performance may be affected. When the width W11 exceeds 5% of the tread ground contact width TW, the actual ground contact area of the first shoulder land portion 25 may be reduced, which may affect grip performance and wear resistance performance.

  The depth of the third narrow groove 11 is desirably 20% to 85% of the rubber thickness of the tread portion 2. If the depth is less than 20% of the rubber thickness, the drainage performance may be affected. When the depth exceeds 85% of the rubber thickness, the rigidity of the first shoulder land portion 25 may be reduced, and the grip performance may be affected. The depth more desirable from the above viewpoint is 35% to 45% of the rubber thickness.

  The depth of the third narrow groove 11 may be different in the tire axial direction. In the present embodiment, the depth of the first narrow groove 9 is equal to that of the first crown main groove 3 and the first inclined groove 5 on the tire equator CL side with respect to the first inclined groove 5 on the first tread grounding end TE1 side. Thus, the depth of the first narrow groove 9 is smaller than that of the first inclined groove 5 on the first tread grounding end TE1 side with respect to the first inclined groove 5.

  The angle of the third narrow groove 11 with respect to the tire axial direction is preferably 45 ° or less. When the angle exceeds 45 °, the rigidity of the first shoulder land portion 25 in the tire axial direction is insufficient, which may affect grip performance and wear resistance performance. A more desirable angle is 0 °. That is, it is desirable that the third narrow groove 11 extends toward the tire equator CL along the tire axial direction.

  In the present embodiment, the third narrow groove 11 communicates with the first crown main groove 3. Such a third narrow groove 11 further optimizes the rigidity of the first shoulder land portion 25 and improves the warming performance of the first tread half portion 21.

  The third narrow groove 11 is disposed on the same axial direction line as the second crown slot 8. Thereby, when a load is applied to the tire for the automobile, the crown land portion 23 and the first shoulder land portion 25 are appropriately bent, and the contact area is increased.

  A fourth narrow groove 12 is provided between the second narrow grooves 10 adjacent to each other in the tire circumferential direction. The fourth narrow groove 12 connects the second crown main groove 4 and the second tread grounding end TE2. The drainage performance of the second shoulder land portion 26 is further enhanced by the fourth narrow groove 12, and the wet performance is improved.

  The width W12, depth, and angle with respect to the tire axial direction of the fourth narrow groove 12 are the same as those of the third narrow groove 11.

  In the present embodiment, the fourth narrow groove 12 communicates with the second crown main groove 4. Due to the fourth narrow groove 12, the rigidity of the second shoulder land portion 26 is further optimized, and the warming performance of the second tread half portion 22 is improved.

  The fourth narrow groove 12 is arranged on the same axial direction line as the first crown slot 7. As a result, when a load is applied to the automobile tire, the crown land portion 23 and the second shoulder land portion 26 are appropriately bent, and the ground contact area is increased.

  The crown land portion 23 has a land portion 23 a in a region facing the third narrow groove 11 through the first crown main groove 3. Further, the crown land portion 23 has a land portion 23 b in a region facing the fourth narrow groove 12 through the second crown main groove 4. Since such a crown land portion 23 is continuous in the tire circumferential direction, it is excellent in rigidity in the tire circumferential direction.

  As shown in FIGS. 1 and 2, the tread portion 2 further includes a first lateral groove 13 and a second lateral groove 14.

  The first lateral groove 13 is formed on the outer side in the tire axial direction than the first tread ground contact TE1 and communicates with the first inclined groove 5 and the first narrow groove 9. The first lateral grooves 13 enhance the drainage performance of the first inclined grooves 5 and the first narrow grooves 9.

  The width W13 of the first lateral groove 13 is desirably 0.5% to 2.0% of the circumference of the automobile four-wheel tire. When the width W13 is less than 0.5% of the circumference, the drainage performance may be affected. When the width W13 exceeds 2.0% of the circumference, the actual ground contact area at the time of cornering may be reduced, and the grip performance and wear resistance performance may be affected.

  The depth of the first lateral groove 13 is the same as that of the first inclined groove 5. The angle of the first lateral groove 13 with respect to the tire axial direction is preferably 45 ° or less. When the angle exceeds 45 °, the rigidity in the tire axial direction of the tread portion 2 outside the first tread ground contact TE1 may be insufficient, which may affect grip performance and wear resistance performance. A more desirable angle is 0 °. That is, it is desirable that the first lateral groove 13 extends along the tire axial direction.

  In the present embodiment, the first inclined groove 5 has a straight part 5 c that extends linearly from the tip part 5 a and a curved part 5 d that is curved and communicates with the first lateral groove 13. In the bent portion 5d, the angle α1 with respect to the tire circumferential direction gradually increases toward the outer side in the tire axial direction. On the other hand, the first lateral groove 13 has a curved portion 13a that is curved and communicates with the first inclined groove 5, and a linear portion 13b that extends linearly. In the bent portion 13a, the angle α3 with respect to the tire circumferential direction gradually increases toward the outer side in the tire axial direction. The bent portion 5d and the bent portion 13a are smoothly connected, and the drainage performance of the first inclined groove 5 is enhanced.

  The second lateral groove 14 is formed on the outer side in the tire axial direction with respect to the second tread ground contact end TE2, and communicates with the second inclined groove 6 and the second narrow groove 10. The drainage performance of the second inclined groove 6 and the second narrow groove 10 is enhanced by the second lateral groove 14.

  The width W14, depth, and angle with respect to the tire axial direction of the second lateral groove 14 are the same as those of the second lateral groove 14.

  In the present embodiment, the second inclined groove 6 has a straight portion 6 c that extends linearly from the tip end portion 6 a and a curved portion 6 d that is curved and communicates with the second lateral groove 14. In the bent portion 6d, the angle α2 with respect to the tire circumferential direction gradually increases toward the outer side in the tire axial direction. On the other hand, the second lateral groove 14 has a curved portion 14a that is curved and communicates with the second inclined groove 6, and a linear portion 14b that extends linearly. In the bent portion 14a, the angle α4 with respect to the tire circumferential direction gradually increases toward the outer side in the tire axial direction. The bent portion 6d and the bent portion 14a are smoothly connected, and the drainage performance of the second inclined groove 6 is enhanced.

  The tread portion 2 further includes a third lateral groove 15 and a fourth lateral groove 16.

  The third lateral groove 15 is formed on the outer side in the tire axial direction with respect to the first tread ground contact end TE1 and communicates with the third narrow groove 11. The drainage performance of the third narrow groove 11 is enhanced by the third lateral groove 15.

  The width W15 of the third lateral groove 15 is larger than the width W13 of the first lateral groove 13. W15 is preferably 2% to 15% of the tread ground contact width TW. When the width W15 is less than 2% of the tread contact width TW, the drainage performance may be affected. When the width W15 exceeds 15% of the tread ground contact width TW, the actual ground contact area during cornering may be reduced, which may affect grip performance and wear resistance.

  The depth of the third lateral groove 15 is desirably 55% to 85% of the rubber thickness of the tread portion 2. If the depth is less than 55% of the rubber thickness, the drainage performance may be affected. If the depth exceeds 85% of the rubber thickness, the grip performance during cornering may be affected. The depth more desirable from the above viewpoint is 65% to 75% of the rubber thickness.

  The angle of the third lateral groove 15 with respect to the tire axial direction is preferably 45 ° or less. When the angle exceeds 45 °, the rigidity in the tire axial direction of the tread portion 2 outside the first tread ground contact TE1 may be insufficient, which may affect grip performance and wear resistance performance. A more desirable angle is 0 °. That is, it is desirable that the third lateral groove 15 extends along the tire axial direction.

  The fourth lateral groove 16 is formed on the outer side in the tire axial direction than the second tread ground contact end TE2 and communicates with the fourth narrow groove 12. The drainage performance of the fourth narrow groove 12 is enhanced by the fourth lateral groove 16.

  The width W16, depth, and angle with respect to the tire axial direction of the fourth lateral groove 16 are the same as those of the third lateral groove 15.

  The shoulder block 29 is divided into a first arrival side block 29 a and a rear arrival side block 29 b in the rotation direction R by the third narrow groove 11. The block 29a is formed integrally with a block 29c disposed outside the first tread grounding end TE1. The block 29b is formed integrally with a block 29d disposed outside the first tread grounding end TE1. The block 29 c and the block 29 d are divided by the first lateral groove 13 and the third lateral groove 15. The block 29c and the block 29d are grounded during cornering.

  The ratio of the sum of the tread areas of the blocks 29a and 29c and the sum of the tread areas of the blocks 29b and 29d is desirably 0.8 to 1.2. When the ratio is 0.8 to 1.2, the distribution of rigidity is made uniform between the first arrival block and the rear arrival block of the third narrow groove 11, and uneven wear is suppressed.

  The shoulder block 30 is divided into a first arrival side block 30 a and a rear arrival side block 30 b in the rotation direction R by the fourth narrow groove 12. The block 30a is formed integrally with a block 30c disposed outside the second tread grounding end TE2. The block 30b is formed integrally with a block 30d disposed outside the second tread grounding end TE2. The block 30 c and the block 30 d are divided by the second lateral groove 14 and the fourth lateral groove 16. The blocks 30c and 30d are grounded during cornering.

  The ratio of the sum of the tread areas of the blocks 30a and 30c and the sum of the tread areas of the blocks 30b and 30d is desirably 0.8 to 1.2. When the ratio is 0.8 to 1.2, the distribution of rigidity is made uniform between the first arrival block and the second arrival block of the fourth narrow groove 12, and uneven wear is suppressed.

  As shown in FIG. 1, the tread portion 2 includes a pair of shoulder regions Sh and Sh, a pair of middle regions Mi and Mi arranged on the inner side in the tire axial direction of the shoulder region Sh, and a middle region Mi and Mi. The center area Ce is divided. The shoulder region Sh is a region of 1/6 of the tread ground contact width TW from the tread ground contact ends TE1 and TE2 to the inside in the tire axial direction. The middle region Mi is a region of 1/6 of the tread contact width TW from the inner end in the tire axial direction of each shoulder region to the inner side in the tire axial direction.

  The land ratio of the center region Ce is preferably 30% to 80%, for example. The “land ratio” is a ratio of the total contact area of the actual land portion to the surface area measured with all the grooves provided in the tread portion 2 being filled. When the land ratio of the center region Ce is less than 30%, the area of the tread surface of each block is insufficient in the center region Ce, and grip performance and wear resistance performance may be deteriorated. On the other hand, when the land ratio of the center region Ce exceeds 80%, the drainage performance may be deteriorated. Further, the warming performance of the tread portion 2 is lowered, and there is a possibility that the grip performance at the initial stage of traveling cannot be sufficiently obtained. From the above viewpoint, a more desirable land ratio of the center region Ce is, for example, 50% to 60%.

  The land ratio of the middle region Mi is preferably 50% to 80%, for example. When the land ratio of the middle region Mi is less than 50%, the area of the tread surface of each block is insufficient in the middle region Mi, and the grip performance and wear resistance performance may be reduced. On the other hand, when the land ratio of the middle region Mi exceeds 80%, the drainage performance may be deteriorated. Further, the warming performance of the tread portion 2 is lowered, and there is a possibility that the grip performance at the initial stage of traveling cannot be sufficiently obtained. From the above viewpoint, a more desirable land ratio of the middle region Mi is, for example, 60 to 70%.

  The land ratio of the shoulder region Sh is preferably 50% to 90%, for example. When the land ratio of the shoulder region Sh is less than 50%, the area of the tread surface of each block is insufficient in the shoulder region Sh, and grip performance and wear resistance performance may be deteriorated. On the other hand, when the land ratio of the shoulder region Sh exceeds 90%, the drainage performance may be deteriorated. Further, the warming performance of the tread portion 2 is lowered, and there is a possibility that the grip performance at the initial stage of traveling cannot be sufficiently obtained. From the above viewpoint, a more desirable land ratio of the shoulder region Sh is, for example, 65 to 75%.

  FIG. 5 is a development view of a tread portion 2A that is a modification of the tread portion 2 of FIG. Regarding the portion of the tread portion 2A that is not described below, the above-described configuration of the tread portion 2 can be employed. In the tread portion 2A, the width W3 of the first crown main groove 3 and the width W4 of the second crown main groove 4 are changed with respect to the tread portion 2. That is, in the tread portion 2A, the width W3 and the width W4 are set small. Accordingly, the width W23 of the crown land portion 23 is expanded. Further, the tire axial lengths of the first crown slot 7 and the second crown slot 8 are set small.

  According to the tread portion 2A, compared to the tread portion 2, the rigidity of the crown land portion 23 is increased, and handling performance and wear resistance performance are improved.

  FIG. 6 is a development view of a tread portion 2B which is another modified example of the tread portion 2 of FIG. Regarding the portion of the tread portion 2B that is not described below, the configuration of the tread portion 2 described above can be adopted. In the tread portion 2B, the first narrow groove 9 terminates at the groove edge 5e on the first tread grounding end TE1 side of the first inclined groove 5, and the second narrow groove 10 is the second tread grounded of the second inclined groove 6. Terminate at the groove edge 6e on the end TE2 side.

  Further, in place of the third fine groove 11 and the fourth fine groove 12, fifth fine grooves 11a, 11b and sixth fine grooves 12a, 12b are provided. The fifth narrow groove 11a extends between the first crown main groove 3 and the first inclined groove 5 along the tire axial direction. The fifth narrow groove 11b extends along the tire axial direction between the adjacent first inclined grooves 5. The fifth narrow groove 11a and the fifth narrow groove 11b are arranged so as to be displaced in the tire circumferential direction. The sixth fine grooves 12a and 12b are the same as the fifth fine groove 11a and the fifth fine groove 11b.

  Furthermore, the third lateral groove 15 extends inward in the tire axial direction from the first tread ground contact end TE1 side, and the end is curved toward the first arrival side in the rotation direction R. The fourth horizontal groove 16 is the same as the third horizontal groove 15.

  According to the tread portion 2B, the rigidity of the first shoulder land portion 25 and the second shoulder land portion 26 is increased as compared with the tread portion 2, and handling performance and wear resistance performance are improved.

  FIG. 7 is a developed view of a tread portion 2C which is still another modification of the tread portion 2 of FIG. Regarding the portion of the tread portion 2C that is not described below, the configuration of the tread portion 2 described above can be employed. In the tread portion 2C, a seventh fine groove 17 is provided between the first fine groove 9 and the third fine groove 11, and an eighth fine groove is provided between the second fine groove 10 and the fourth fine groove 12. 18 is provided. Accordingly, the first narrow groove 9 and the second narrow groove 10 are moved to the arrival side in the rotation direction R, and the third narrow groove 11 and the fourth narrow groove 12 are moved to the arrival side in the rotation direction R. .

  According to the tread portion 2C, compared with the tread portion 2, the drainage performance of the first shoulder land portion 25 and the second shoulder land portion 26 is enhanced, and the wet performance is improved.

  As described above, the automobile tire according to the present invention has been described in detail. However, the present invention is not limited to the above-described specific embodiment, but can be implemented in various forms.

A racing cart tire having the tread pattern of FIG. 1 was prototyped based on the specifications shown in Table 1, and mounted on all wheels of a 100 cc four-wheel racing cart under the following conditions, and various performances were tested. The test method is as follows.
<Front wheel>
Size: 10x4.50-5
Rims: 4.5
Internal pressure: 100kPa
<Rear wheel>
Size: 11x6.50-5
Rims: 6.5
Internal pressure: 100kPa

<Wet grip performance>
Each test tire was mounted on all wheels of a two-cycle four-wheel racing cart with a displacement of 100 cc under the following conditions. Then, the test driver drove a test course on the asphalt road surface with a circumference of 734 m in a wet state with a water depth of 5 mm, and the grip performance at this time was evaluated by the test driver's sensuality. The results are displayed in a 5-point method with Example 3 as 5.0. It can be evaluated that the larger the value, the better and the grip performance.

<Abrasion resistance>
The test driver observed crusted wear (abrasion wear) on the surface of the tread after the above running. The result is displayed by a five-point method in which the wear state is scored by the following evaluation method. The larger the value, the better.
1: Serious abrasion wear occurred.
2: Moderate abrasion wear occurred.
3: Mild abrasion wear occurred.
4: Signs of abrasion wear were observed.
5: No abrasion wear occurred. Generated on the surface of the tread,

<Running time (time trial)>
In the test vehicle, the test driver drove the test course on the asphalt road surface with one lap of 734 m for seven laps each in a wet state with a water depth of 5 mm. The results are displayed by a 5-point method in which the total running time in each state is scored by the following evaluation method. The larger the value, the better.
1.0: Fastest time + 3.0 seconds or more 1.5: Fastest time + 2.5 seconds or more, less than 3.0 seconds 2.0: Fastest time + 2.0 seconds or more, less than 2.5 seconds 2.5: Fastest time Time + 1.5 seconds or more and less than 2.0 seconds 3.0: Fastest time + 1.0 seconds or more and less than 1.5 seconds 3.5: Fastest time + 0.5 seconds or more and less than 1.0 seconds 4.0: Fastest time + 0.2 seconds or more, less than 0.5 seconds 4.5: Fastest time + less than 0.2 seconds 5.0: Fastest time

<Overall performance>
The total performance is an average value of the test results of grip performance, wear resistance performance and running time.
Table 1 shows the test results.

  As is clear from Table 1, it was confirmed that the performance of the automobile tires of the examples was significantly improved in a balanced manner as compared with the comparative examples.

DESCRIPTION OF SYMBOLS 1 Tire for four-wheeled vehicles 2 Tread part 3 1st crown main groove 4 2nd crown main groove 5 1st inclination groove 5a Tip part 6 2nd inclination groove 6a Tip part 7 1st crown slot 8 2nd crown slot 9 1st 1 narrow groove 10 2nd narrow groove 11 3rd narrow groove 12 4th narrow groove 21 1st tread half part 22 2nd tread half part

Claims (12)

A tire for an automobile with a tread,
The tread portion is
There is a first tread half from the tire equator to the first tread ground end, and a second tread half from the tire equator to the second tread ground end, which is the tread ground end opposite to the first tread ground end. And
A first crown main groove extending continuously in the tire circumferential direction is provided in the first tread half, and a second crown main groove extending continuously in the tire circumferential direction is provided in the second tread half.
The tread portion includes a crown land portion between the first crown main groove and the second crown main groove, a first shoulder land portion between the first crown main groove and the first tread grounding end, and , Divided into a second shoulder land portion between the second crown main groove and the second tread grounding end,
The first shoulder land portion includes a plurality of first inclined grooves that are inclined with respect to the tire circumferential direction from the tip portion on the first tread grounding end side with respect to the first crown main groove and extend to the first tread grounding end. Is provided,
The second shoulder land portion includes a plurality of slopes extending in a direction opposite to the first inclined groove from the tip portion on the second tread grounding end side with respect to the second crown main groove and extending to the second tread grounding end. A second inclined groove is provided;
The crown land portion is
It is formed in a rib shape continuous in the tire circumferential direction,
A plurality of first crown slots extending from the first crown main groove toward the tire equator and terminating at the crown land portion, and extending from the second crown main groove toward the tire equator and terminating at the crown land portion have a plurality of second crown slot having,
An automobile tire according to claim 1, wherein an angle of the first crown slot and the second crown slot with respect to a tire axial direction is 45 ° or less . A tire for an automobile with a tread,
The tread portion is
There is a first tread half from the tire equator to the first tread ground end, and a second tread half from the tire equator to the second tread ground end, which is the tread ground end opposite to the first tread ground end. And
A first crown main groove extending continuously in the tire circumferential direction is provided in the first tread half, and a second crown main groove extending continuously in the tire circumferential direction is provided in the second tread half.
The tread portion includes a crown land portion between the first crown main groove and the second crown main groove, a first shoulder land portion between the first crown main groove and the first tread grounding end, and , Divided into a second shoulder land portion between the second crown main groove and the second tread grounding end,
The first shoulder land portion includes a plurality of first inclined grooves that are inclined with respect to the tire circumferential direction from the tip portion on the first tread grounding end side with respect to the first crown main groove and extend to the first tread grounding end. Is provided,
The second shoulder land portion includes a plurality of slopes extending in a direction opposite to the first inclined groove from the tip portion on the second tread grounding end side with respect to the second crown main groove and extending to the second tread grounding end. A second inclined groove is provided;
The crown land portion is
It is formed in a rib shape continuous in the tire circumferential direction,
A plurality of first crown slots extending from the first crown main groove toward the tire equator and terminating at the crown land portion, and extending from the second crown main groove toward the tire equator and terminating at the crown land portion A plurality of second crown slots having
The width of the first crown slot and the second crown slot is 1% to 5% of the tread ground contact width . A tire for an automobile with a tread,
The tread portion is
There is a first tread half from the tire equator to the first tread ground end, and a second tread half from the tire equator to the second tread ground end, which is the tread ground end opposite to the first tread ground end. And
A first crown main groove extending continuously in the tire circumferential direction is provided in the first tread half, and a second crown main groove extending continuously in the tire circumferential direction is provided in the second tread half.
The tread portion includes a crown land portion between the first crown main groove and the second crown main groove, a first shoulder land portion between the first crown main groove and the first tread grounding end, and , Divided into a second shoulder land portion between the second crown main groove and the second tread grounding end,
The first shoulder land portion includes a plurality of first inclined grooves that are inclined with respect to the tire circumferential direction from the tip portion on the first tread grounding end side with respect to the first crown main groove and extend to the first tread grounding end. Is provided,
The second shoulder land portion includes a plurality of slopes extending in a direction opposite to the first inclined groove from the tip portion on the second tread grounding end side with respect to the second crown main groove and extending to the second tread grounding end. A second inclined groove is provided;
The crown land portion is
It is formed in a rib shape continuous in the tire circumferential direction,
A plurality of first crown slots extending from the first crown main groove toward the tire equator and terminating at the crown land portion, and extending from the second crown main groove toward the tire equator and terminating at the crown land portion A plurality of second crown slots having
The first shoulder land portion is provided with a first narrow groove extending from an edge of the first inclined groove on the first tread grounding end side toward the tire equator,
The second shoulder land portion is provided with a second narrow groove extending from the edge of the second inclined groove on the second tread grounding end side toward the tire equator,
The width of the first narrow groove and the second narrow groove is 1% to 5% of the tread contact width . A tire for an automobile with a tread,
The tread portion is
There is a first tread half from the tire equator to the first tread ground end, and a second tread half from the tire equator to the second tread ground end, which is the tread ground end opposite to the first tread ground end. And
A first crown main groove extending continuously in the tire circumferential direction is provided in the first tread half, and a second crown main groove extending continuously in the tire circumferential direction is provided in the second tread half.
The tread portion includes a crown land portion between the first crown main groove and the second crown main groove, a first shoulder land portion between the first crown main groove and the first tread grounding end, and , Divided into a second shoulder land portion between the second crown main groove and the second tread grounding end,
The first shoulder land portion includes a plurality of first inclined grooves that are inclined with respect to the tire circumferential direction from the tip portion on the first tread grounding end side with respect to the first crown main groove and extend to the first tread grounding end. Is provided,
The second shoulder land portion includes a plurality of slopes extending in a direction opposite to the first inclined groove from the tip portion on the second tread grounding end side with respect to the second crown main groove and extending to the second tread grounding end. A second inclined groove is provided;
The crown land portion is
It is formed in a rib shape continuous in the tire circumferential direction,
A plurality of first crown slots extending from the first crown main groove toward the tire equator and terminating at the crown land portion, and extending from the second crown main groove toward the tire equator and terminating at the crown land portion A plurality of second crown slots having
The first shoulder land portion is provided with a first narrow groove extending from an edge of the first inclined groove on the first tread grounding end side toward the tire equator,
The second shoulder land portion is provided with a second narrow groove extending from the edge of the second inclined groove on the second tread grounding end side toward the tire equator,
The tire for an automobile according to claim 1, wherein the first narrow groove communicates with the first crown main groove, and the second narrow groove communicates with the second crown main groove . The first narrow groove is disposed on the same axial direction line as the first crown slot,
The tire for an automobile according to claim 4, wherein the second narrow groove is arranged on the same axial direction line as the second crown slot. A third narrow groove that connects the first crown main groove and the first tread grounding end is provided between the first narrow grooves adjacent in the tire circumferential direction,
The fourth narrow groove that connects the second crown main groove and the second tread grounding end is provided between the second narrow grooves adjacent to each other in the tire circumferential direction. The tire for automobiles described. The crown land portion is
A land portion in a region facing the third narrow groove via the first crown main groove;
The tire for a four-wheeled vehicle according to claim 6, further comprising a land portion in a region facing the fourth narrow groove through the second crown main groove. The first narrow groove terminates at a groove edge on the first tread grounding end side of the first inclined groove,
The tire for an automobile according to claim 3, wherein the second narrow groove terminates at a groove edge on the second tread grounding end side of the second inclined groove. A tire for an automobile with a tread,
The tread portion is
There is a first tread half from the tire equator to the first tread ground end, and a second tread half from the tire equator to the second tread ground end, which is the tread ground end opposite to the first tread ground end. And
A first crown main groove extending continuously in the tire circumferential direction is provided in the first tread half, and a second crown main groove extending continuously in the tire circumferential direction is provided in the second tread half.
The tread portion includes a crown land portion between the first crown main groove and the second crown main groove, a first shoulder land portion between the first crown main groove and the first tread grounding end, and , Divided into a second shoulder land portion between the second crown main groove and the second tread grounding end,
The first shoulder land portion includes a plurality of first inclined grooves that are inclined with respect to the tire circumferential direction from the tip portion on the first tread grounding end side with respect to the first crown main groove and extend to the first tread grounding end. Is provided,
The second shoulder land portion includes a plurality of slopes extending in a direction opposite to the first inclined groove from the tip portion on the second tread grounding end side with respect to the second crown main groove and extending to the second tread grounding end. A second inclined groove is provided;
The crown land portion is
It is formed in a rib shape continuous in the tire circumferential direction,
A plurality of first crown slots extending from the first crown main groove toward the tire equator and terminating at the crown land portion, and extending from the second crown main groove toward the tire equator and terminating at the crown land portion A plurality of second crown slots having
The first shoulder land portion is provided with a first narrow groove extending from an edge of the first inclined groove on the first tread grounding end side toward the tire equator,
The second shoulder land portion is provided with a second narrow groove extending from the edge of the second inclined groove on the second tread grounding end side toward the tire equator,
Between the first narrow grooves adjacent in the tire circumferential direction, a fifth narrow groove extending from the first inclined groove toward the tire equator is provided,
A four-wheeled vehicle tire characterized in that a sixth narrow groove extending from the second inclined groove toward the tire equator is provided between the second narrow grooves adjacent to each other in the tire circumferential direction.   The length of the crown land portion in the tire axial direction is 5% to 20% of a tread ground contact width that is a length in the tire axial direction from the first tread ground contact end to the second tread ground contact end. A tire for an automobile according to any one of the above. A first lateral groove formed on the outer side in the tire axial direction from the first tread grounding end, and communicated with the first inclined groove;
The tire for a four-wheeled vehicle according to any one of claims 1 to 10, further comprising a second lateral groove formed outside the second tread ground contact end in the tire axial direction and communicating with the second inclined groove. A third lateral groove that is formed on the outer side in the tire axial direction than the first tread grounding end and communicates with the third narrow groove;
The tire for a four-wheeled vehicle according to claim 6 or 7, further comprising a fourth lateral groove formed outside the second tread ground contact end in the tire axial direction and communicating with the fourth narrow groove.

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