JP2011105104A - Tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire further improving on-snow/ice performance, while maintaining the rigidity of a block. <P>SOLUTION: Width directional sipes 100 and 102 extending in a zigzag shape along the tread width direction TW are formed in the blocks 24 and 26 partitioned by peripheral directional grooves 40, 42, 44 and 46 extending along the tire circumferential direction TC and peripheral grooves 60, 62, 64 and 66 extending along the tread width direction TW. The blocks 24 and 26 include an inside block 20 arranged inside when installed in a vehicle and an outside block 28 arranged outside when installed in the vehicle. The inside block 20 is formed with a first peripheral directional sipe 50 extending along the tire circumferential direction TC, shallower in the groove depth than the width directional sipe 100 and shallow in the groove depth on the central side of the inside block 20. The outside block 28 is formed with a second peripheral directional sipe 52 extending along the tire circumferential direction TC, shallower in the groove depth than the width directional sipe 100 and shallow in the groove depth on both end sides of the outside block 28. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes a block defined by a circumferential groove extending along the tire circumferential direction and a lateral groove extending along the tread width direction, and a sipe extending zigzag along the tread width direction is formed in the block. In particular, the present invention relates to a tire that further improves the performance on snow and ice while ensuring the rigidity of the block.

  Conventionally, tires suitable for running on icy and snowy roads have a zigzag-like shape extending along the tread width direction in a tread block in order to improve braking force and traction (hereinafter referred to as snow and ice performance) on icy and snowy roads. A method of forming a sipe or increasing the depth of a sipe is widely used.

  In such a sipe-formed tire, in order to improve the rigidity of the block, both ends of the block in the tread width direction are provided with bottom raised portions extending from the bottom forming the sipe bottom in the tire radial direction, A method of reducing the groove depth at both ends is widely known (for example, Patent Document 1).

Japanese Patent Laying-Open No. 2005-119415 (pages 5-6, 2 and 3)

  However, the conventional tire described above has the following problems. In other words, the rigidity of the block can be improved, but at the both ends of the sipe along the tread width direction, the sipe does not open along the tire circumferential direction, and the snow column shearing force acting on the snow entering the sipe, or the edge of the sipe or tread pattern The edge effect (digging frictional force) acting on the snow cannot be obtained, and there is a problem that the performance on snow and ice, specifically, the braking force and traction on the ice and snow road decrease.

  Therefore, an object of the present invention is to provide a tire that further improves the performance on snow and ice while maintaining the rigidity of the block.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is that a circumferential groove (for example, circumferential groove 40) extending along the tire circumferential direction (tire circumferential direction TC) and a lateral groove (for example, lateral groove 60) extending along the tread width direction. ) And a plurality of blocks (for example, the block 24), and a widthwise sipe (for example, the widthwise sipe 100) extending in a zigzag shape along the tread width direction (tread width direction TW) is formed in the block. And at least one end of the widthwise sipe is a tire that communicates with the circumferential groove at an end along the tread width direction of the block, and the block is an inner block (for example, provided on the inner side when the vehicle is mounted) The inner block 20) and an outer block (for example, the outer block 28) provided outside the inner block when the vehicle is mounted, The side block has a first circumferential sipe extending along the tire circumferential direction and having a groove depth shallower than that of the widthwise sipe and having a groove depth shallower on the center side of the inner block in the tire circumferential direction (for example, The first circumferential sipe 50) is formed, and the outer block extends along the tire circumferential direction and has a groove depth shallower than that of the width sipe, at both ends of the outer block in the tire circumferential direction. The gist is that a second circumferential sipe (for example, the second circumferential sipe 52) having a shallow groove depth is formed.

  According to such a tire, the inner block is formed with the first circumferential sipe having a groove depth shallower than the groove depth of the width direction sipe, and the outer block is grooved more than the groove depth of the width direction sipe. A second circumferential sipe having a shallow depth is formed. For this reason, the 1st circumferential direction sipe and the 2nd circumferential direction sipe can suppress that the rigidity of an inner side block and an outer side block falls, ensuring the drainage nature along a tire peripheral direction. In addition, the inner block and the outer block can effectively increase the length of the edge in the width direction sipe or the width direction sipe rather than two blocks arranged in the tread width direction via the circumferential groove, The performance on snow and ice can be further improved.

  The inner block is formed with a first circumferential sipe in which the groove depth becomes shallower on the center side of the inner block in the tire circumferential direction. For this reason, the rigidity of the edge part of the tire peripheral direction in an inner side block falls rather than the rigidity of the center side of an inner side block. Thereby, in the edge part of the tire circumferential direction of an inner side block, a 1st circumferential direction sipe becomes easy to open in a tread width direction, and it can increase traction. In particular, when the negative camber is applied to the tire, the contact pressure of the inner block is higher than the contact pressure of the outer block, so that the traction can be increased more effectively.

  On the other hand, a second circumferential sipe in which the groove depth becomes shallower at both ends of the outer block in the tire circumferential direction is formed in the outer block. For this reason, the rigidity of the edge part of the tire circumferential direction in an outer side block becomes higher than the rigidity of the center side of an inner side block. Thereby, at the time of tire braking, the outer block is less likely to fall down, and the braking force can be improved.

  Therefore, it is possible to provide a tire that further improves the performance on snow and ice while maintaining the rigidity of the block.

  The second feature of the present invention is related to the first feature of the present invention, wherein the groove depth of the first circumferential sipe is deeper on the stepping side than on the kicking side in the tire circumferential direction. .

  A third feature of the present invention relates to the first or second feature of the present invention, wherein the groove depth of the second circumferential sipe is deeper on the stepping side than on the kicking side in the tire circumferential direction. The gist.

  According to the characteristics of the present invention, it is possible to provide a tire that further improves the performance on snow and ice while maintaining the rigidity of the block.

It is an expanded view of the tread which comprises the pneumatic tire concerning the embodiment of the present invention. It is a partial exploded perspective view of a block which constitutes a pneumatic tire concerning an embodiment of the present invention. It is sectional drawing of the block which comprises the pneumatic tire which concerns on embodiment of this invention. Fig.3 (a) is AA cross section of FIG. 1, and is sectional drawing of the block which passes along a 1st circumferential direction sipe. FIG. 3B is a cross-sectional view of the block taken along the line BB of FIG. 1 and passing through the second circumferential sipe. It is sectional drawing of the block which comprises the pneumatic tire which concerns on the modification of embodiment of this invention. FIG. 4A is a cross-sectional view of a block passing through the first circumferential sipe. FIG. 4B is a cross-sectional view of the block passing through the second circumferential sipe.

  Next, first to sixth embodiments of the pneumatic tire according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[Embodiment]
In this embodiment, (1) Configuration of pneumatic tire, (2) Detailed configuration of block, (3) Action and effect, (4) Modification, (5) Comparative evaluation, and (6) Other embodiments Will be described.

(1) Configuration of Pneumatic Tire FIG. 1 is a development view of a tread constituting the pneumatic tire 1 according to the embodiment of the present invention. The pneumatic tire 1 is a so-called studless tire suitable for traveling on icy and snowy roads. Each part formed in the tread in the pneumatic tire 1 will be further described.

  The tread portion 10 of the pneumatic tire 1 has circumferential grooves 40, 42, 44, 46 extending along the tire circumferential direction TC, and lateral grooves 60, 62, 64, 66, 68 extending along the tread width direction TW. Is formed. The circumferential grooves 40, 42, 44, and 46 are sequentially positioned from the inside to the outside when the tire vehicle is mounted. The lateral grooves 60, 62, 64, 66, 68 are sequentially located from the inside to the outside when the tire vehicle is mounted. The pneumatic tire 1 is a tire in which an inner side and an outer side are designated when the vehicle is mounted. The pneumatic tire 1 indicates whether it is mounted on the inside or the outside when the vehicle is mounted. For example, when the vehicle is mounted, whether it is mounted inside or outside is marked on the surface of the pneumatic tire 1.

  The pneumatic tire 1 is a tire in which a kick side and a stepping side are designated when forward rotation is performed when the vehicle is mounted. The pneumatic tire 1 shows whether to be mounted on the kick side or the tread side when forwardly rotated. For example, the pneumatic tire 1 is marked on the surface of the pneumatic tire 1 as to whether the pneumatic tire 1 is mounted on the kicking side or the stepping side when forwardly rotating.

(2) Detailed Configuration of Block The detailed configuration of the block will be described with reference to FIGS. FIG. 2 is a partially exploded perspective view of the inner block 20 constituting the pneumatic tire 1 according to the embodiment of the present invention. In FIG. 2, a partial cross section of the inner block 20 forming the first circumferential sipe 50 is indicated by hatching. 3 is a cross-sectional view taken along line AA and BB in FIG. 1. Specifically, FIG. 3A is a cross-sectional view passing through the first circumferential sipe 50 of the inner block 20 constituting the pneumatic tire 1 according to the embodiment of the present invention. FIG.3 (b) is sectional drawing which passes along the 2nd circumferential direction sipe 52 of the outer side block 28 which comprises the pneumatic tire 1 which concerns on embodiment of this invention.

  As shown in FIG. 1, the pneumatic tire 1 includes a plurality of blocks defined by a circumferential groove and a lateral groove. The block includes an inner block provided on the inner side (IN side shown in FIG. 1) when the vehicle is mounted, and an outer block provided on the outer side (OUT side shown in FIG. 1) than the inner block.

  Specifically, the pneumatic tire 1 includes an inner block 20, an inner block 22, a block 24, a block 26, and an outer block 28. The inner block 20 is partitioned by a circumferential groove 40 and a lateral groove 60. The inner block 22 is partitioned by a circumferential groove 40, a circumferential groove 42, and a lateral groove 62. The block 24 is partitioned by a circumferential groove 42, a circumferential groove 44, and a lateral groove 64. The block 26 is partitioned by a circumferential groove 44, a circumferential groove 46, and a lateral groove 66. The outer block 28 is defined by a circumferential groove 46 and a lateral groove 68.

  Each block is formed with a width direction sipe extending zigzag along the tread width direction TW. At least one end of the width direction sipe communicates with the circumferential groove at an end portion along the tread width direction of the block. Hereinafter, (2.1) inner block and (2.2) outer block will be described in more detail. As for the inner block, in the following details, only the inner block 20 is described, and the inner block 22 is not described in order to omit duplication. However, the inner block 22 has the same characteristics as the inner block 20. For example, the inner block 22 is formed with a width direction sipe 100 and a first circumferential direction sipe 54.

(2.1) Inner Block As shown in FIG. 1, a width direction sipe 100 and a first circumferential direction sipe 50 are formed in the inner block 20. One end of the width direction sipe 100 on the tire equator line CL side communicates with the circumferential groove 40 at the end of the inner block 20 on the tire equator line CL side along the tread width direction TW. A plurality of the width direction sipes 100 are formed on the inner block 20 along the tire circumferential direction TC.

  The first circumferential sipe 50 extends along the tire circumferential direction TC. The first circumferential sipe 50 is formed at a position corresponding to 1/3 L from the end of the inner block 20 on the tire equator line CL side with respect to the width L along the tread width direction TW of the inner block 20. The width L along the tread width direction TW of the inner block 20 is the width from the end of the inner block 20 on the tire equator line CL side to the ground contact end outside the tread width direction TW. Specifically, the width L along the tread width direction TW of the inner block 20 is set to a normal internal pressure defined by JATMA or the like after the internal pressure of the pneumatic tire 1 is set, and a mass corresponding to a normal load is added to In the pneumatic tire 1 in this state, the width from the end on the tire equator line CL side of the inner block 20 that contacts the road surface to the contact end on the outer side of the tread width direction TW is shown.

  Both ends of the first circumferential sipe 50 communicate with the lateral groove 60 on the kick side and the lateral groove 60 on the tread side. Specifically, as shown in FIG. 3A, the inner block 20 has a raised bottom portion 116 that forms a first circumferential sipe 50, a kick side bottom portion 112, and a tread side bottom portion 114. The kick side bottom portion 112, the stepping side bottom portion 114, and the raised bottom portion 116 are formed in a substantially linear shape along the tire circumferential direction TC. The raised bottom portion 116 extends to both ends on the kick side and the step side from the width direction sipe 100 along the tire circumferential direction TC. The width of the raised bottom portion 116 along the tire circumferential direction TC is set to 75% to 90% of the width of the inner block 20 along the tire circumferential direction TC. Similarly, the width along the tire circumferential direction TC of the kick side bottom portion 112 and the tread side bottom portion 114 is set to a length of 5% to 15% of the width along the tire circumferential direction TC of the inner block 20.

  The depths from the contact surface G of the tread portion 10 to the kick side bottom portion 112, the tread side bottom portion 114, and the raised bottom portion 116 are defined as a groove depth H12, a groove depth H14, and a groove depth H16, respectively. Further, the depth from the ground contact surface G of the tread portion 10 to the bottom of the width-direction sipe 100 and the depth from the bottom 110, which is the bottom of the lateral groove 60, are defined as a groove depth H100 and a groove depth H10, respectively. The groove depth of the first circumferential sipe 50 is shallower than the groove depth of the widthwise sipe 100, and the groove depth is shallower on the center side of the inner block 20 in the tire circumferential direction TC. That is, the groove depth H12, the groove depth H14, and the groove depth H16 are shallower than the groove depth H100. Further, the groove depth H16 is shallower than the groove depth H12 and the groove depth H14. The groove depth of the first circumferential sipe 50 is deeper on the stepping side than on the kicking side in the tire circumferential direction TC. That is, the groove depth H14 of the first circumferential sipe 50 is deeper than the groove depth H12. The groove depth H100 is shallower than the groove depth H10. Specifically, on the basis of the groove depth H100, the groove depth H10 is set to a depth of 75% to 85% of the groove depth H100. The groove depth H12 and the groove depth H14 are set to a depth of 40% to 55% of the groove depth H100. For example, the groove depth H100 is set to 6 mm, and the groove depth H12 and the groove depth H14 are set to 2.5 mm. The groove depth H16 is set to a depth of 10% to 30% of the groove depth H100. For example, the groove depth H16 is set to 1.5 mm.

(2.2) Outer Block As shown in FIG. 1, a width direction sipe 102 and a second circumferential direction sipe 52 are formed in the outer block 28. One end of the width direction sipe 102 on the tire equator line CL side communicates with the circumferential groove 46 at an end portion on the tire equator line CL side along the tread width direction TW of the outer block 28. A plurality of width direction sipes 102 are formed in the outer block 28 along the tire circumferential direction TC.

  The second circumferential sipe 52 extends along the tire circumferential direction TC. The second circumferential sipe 52 extends along the tire circumferential direction TC. The second circumferential sipe 52 is formed at a position corresponding to 1/3 L from the end of the outer block 28 on the tire equator line CL side with respect to the width L along the tread width direction TW of the outer block 28. The width L along the tread width direction TW of the outer block 28 is the width from the end of the outer block 28 on the tire equator line CL side to the ground contact end outside the tread width direction TW. Specifically, the width L along the tread width direction TW of the outer block 28 is set to a normal internal pressure defined by JATMA or the like after the internal pressure of the pneumatic tire 1 is set, and a mass corresponding to a normal load is added to In the pneumatic tire 1 in this state, the width from the end on the tire equator line CL side of the outer block 28 that contacts the road surface to the contact end on the outer side of the tread width direction TW is shown.

  Both ends of the second circumferential sipe 52 communicate with the lateral groove 68 on the kick side and the lateral groove 68 on the tread side. Specifically, as shown in FIG. 3B, the outer block 28 has a bottom portion 122 that forms the second circumferential sipe 52, a kick side bottom portion 124, and a tread side bottom portion 126. The kick side bottom portion 124, the stepping side bottom portion 126, and the bottom portion 122 are formed in a substantially straight shape along the tire circumferential direction TC. The bottom portion 122 extends along the tire circumferential direction TC to both ends on the kick side and the tread side from the width direction sipe 102. The width of the bottom portion 122 along the tire circumferential direction TC is set to 75% to 90% of the width of the outer block 28 along the tire circumferential direction TC. Similarly, the width along the tire circumferential direction TC of the kick side bottom portion 124 and the tread side bottom portion 126 is set to a length of 5% to 15% of the width along the tire circumferential direction TC of the outer block 28. .

  The depths from the contact surface G of the tread portion 10 to the bottom portion 122, the kick side bottom portion 124, and the tread side bottom portion 126 are defined as a groove depth H22, a groove depth H24, and a groove depth H26, respectively. Further, the depth from the ground contact surface G of the tread portion 10 to the bottom of the width-direction sipe 102 and the depth from the bottom 120, which is the bottom of the lateral groove 68, are defined as a groove depth H102 and a groove depth H20, respectively. The groove depth of the second circumferential sipe 52 is shallower than the groove depth of the widthwise sipe 102, and the groove depth is shallow at both ends of the outer block 28 in the tire circumferential direction TC. That is, the groove depth H22, the groove depth H24, and the groove depth H26 are shallower than the groove depth H102. Further, the groove depth H24 and the groove depth H26 are shallower than the groove depth H22. The groove depth of the second circumferential sipe 52 is deeper on the stepping side than on the kicking side in the tire circumferential direction TC. That is, the groove depth H26 of the second circumferential sipe 52 is deeper than the groove depth H24. The groove depth H102 is shallower than the groove depth H20. Specifically, on the basis of the groove depth H102, the groove depth H20 is set to a depth of 75% to 85% of the groove depth H102. The groove depth H24 and the groove depth H26 are set to a depth of 10% to 30% of the groove depth H102. For example, the groove depth H102 is set to 6 mm, and the groove depth H24 and the groove depth H26 are set to 1.5 mm. The groove depth H22 is set to a depth of 40% to 55% of the groove depth H102. For example, the groove depth H12 and the groove depth H14 are set to 2.5 mm.

(3) Actions / Effects As described above, according to the present embodiment, the inner circumferential block 20 is formed with the first circumferential sipe 50 whose groove depth is shallower than the groove depth of the widthwise sipe 100, and A second circumferential sipe 52 having a groove depth shallower than the groove depth of the width direction sipe 102 is formed in the block 28. For this reason, the 1st circumferential direction sipe 50 and the 2nd circumferential direction sipe 52 can suppress that the rigidity of the inner side block 20 and the outer side block 28 falls, ensuring the drainage property along the tire circumferential direction TC. Further, the inner block 20 and the outer block 28 are more effective in the length of the edge by the width sipe 100 or the width sipe 102 than when two blocks are arranged in the tread width direction TW via the circumferential groove. Therefore, the performance on snow and ice can be further improved.

  Further, the inner block 20 is formed with a first circumferential sipe 50 in which the groove depth is shallow on the center side of the inner block 20 in the tire circumferential direction TC. For this reason, the rigidity of the end portion in the tire circumferential direction TC in the inner block 20 is lower than the rigidity on the center side of the inner block 20. Thereby, in the edge part of the tire circumferential direction TC of the inner side block 20, the 1st circumferential direction sipe 50 becomes easy to open in the tread width direction TW, and can increase a traction. In particular, when the negative camber is applied to the pneumatic tire 1, the ground pressure of the inner block 20 is higher than the ground pressure of the outer block 28, so that traction can be increased more effectively.

  On the other hand, the outer circumferential block 28 is formed with a second circumferential sipe 52 in which the groove depth becomes shallower at both ends of the outer block 28 in the tire circumferential direction TC. For this reason, the rigidity of the end portion in the tire circumferential direction TC in the outer block 28 is higher than the rigidity on the center side of the inner block 20. Thereby, at the time of tire braking, the outer block 28 is unlikely to fall down, and the braking force can be improved.

  Therefore, it is possible to provide the pneumatic tire 1 in which the performance on snow and ice is further improved while maintaining the rigidity of the block.

  According to the present embodiment, the groove depth of the first circumferential sipe 50 is deeper on the stepping side than the kicking side in the tire circumferential direction TC. For this reason, since more snow enters the first circumferential sipe 50 when stepped on, the snow column shear force is improved, and the traction can be further increased. Further, since the rigidity of the inner block 20 increases on the kicking side, uneven wear during braking, that is, heel and toe wear can be suppressed.

  According to the present embodiment, the groove depth of the second circumferential sipe 52 is deeper on the stepping side than on the kicking side in the tire circumferential direction TC. For this reason, since the rigidity of the outer block 28 increases on the kicking side, uneven wear during braking, that is, heel and toe wear can be suppressed. In addition, since more snow enters the second circumferential sipe 52 when stepped on, the snow column shear force is improved and the performance on snow and ice can be further improved.

(4) Modification A modification of the present embodiment will be described with reference to FIG. FIG. 4 is a cross-sectional view taken along the tire radial direction TD and the tire circumferential direction TC of a block according to a modification of the present embodiment. Specifically, FIG. 4A is a cross-sectional view passing through the first circumferential sipe 50A of the inner block 20A according to the modification of the present invention. FIG. 4B is a cross-sectional view passing through the second circumferential sipe 52A of the outer block 28A according to the modification of the present invention. Note that, in the following modifications, differences from the embodiment will be mainly described, and redundant description will be omitted.

  In the above-described embodiment, the kick side bottom portion 112, the stepping side bottom portion 114, and the raised bottom portion 116 of the first circumferential sipe 50 are formed in a substantially linear shape along the tire circumferential direction TC. Further, the kick side bottom portion 124, the tread side bottom portion 126, and the bottom portion 122 of the second circumferential direction sipe 52 are formed in a substantially linear shape along the tire circumferential direction TC. On the other hand, in the modification of the present invention, the bottom 112A of the first circumferential sipe 50A is formed in a curved shape. Specifically, the groove depth of the first circumferential sipe 50A is shallower than the groove depth of the widthwise sipe 100A, and the groove depth is shallower on the center side of the inner block 20A in the tire circumferential direction TC. That is, the bottom 112A of the first circumferential sipe 50A is formed in a curved shape that protrudes outward in the tire radial direction TD on the center side of the inner block 20A in the tire circumferential direction TC. The depth from the ground contact surface G of the tread portion 10 to both ends and the center of the bottom 112A in the tire circumferential direction TC is defined as a groove depth H12, a groove depth H14, and a groove depth H16, respectively.

  In the modification of the present invention, the bottom 122A of the second circumferential sipe 52A is formed in a curved shape. Specifically, the groove depth of the second circumferential sipe 52A is shallower than the groove depth of the widthwise sipe 102A, and the groove depth is shallow at both ends of the outer block 28A in the tire circumferential direction TC. That is, the bottom 122A of the second circumferential sipe 52A is formed in a curved shape that protrudes inward in the tire radial direction TD on the center side of the outer block 28A in the tire circumferential direction TC. The depth from the ground contact surface G of the tread portion 10 to both end portions and the center portion of the bottom portion 122A in the tire circumferential direction TC is defined as a groove depth H26, a groove depth H24, and a groove depth H22, respectively.

  According to such a modification, when the first circumferential sipe 50A and the second circumferential sipe 52A are opened in the tread width direction TW, compared to the first circumferential sipe 50 and the second circumferential sipe 52, Since it can suppress that stress concentrates on one part, it can suppress that the rigidity of a block falls and can control generation of a crack.

(5) Comparative Evaluation Next, in order to further clarify the effect of the present invention, comparative evaluation performed using pneumatic tires according to the following comparative examples and examples will be described. Specifically, (5.1) Evaluation method and (5.2) Evaluation result will be described. In addition, this invention is not limited at all by these examples.

(5.1) Evaluation method Using each pneumatic tire, (5.1.1) traction evaluation, (5.1.2) braking force evaluation, and (5.1.3) ride comfort evaluation are evaluated. went. Data on pneumatic tires were measured under the following conditions.

・ Tire size: 185 / 65R16
・ Rim wheel size: Width 5.5JJ
・ Load conditions: Vehicle weight + 2 test drivers ・ Internal pressure: 220 kPa
・ Evaluation vehicle: FF sedan (2000 cc displacement)
Each pneumatic tire has a different circumferential sipe shape. Hereinafter, the different points will be described in detail.

  The pneumatic tire according to Example 1 has the same configuration as the pneumatic tire 1 according to the embodiment. The pneumatic tire according to Example 2 has the same configuration as the pneumatic tire according to the modification of the embodiment.

  The pneumatic tire according to the comparative example differs from the pneumatic tire 1 according to the embodiment in that no circumferential sipe is provided along the tire circumferential direction.

(5.1.1) Traction evaluation Evaluation method: Vehicles equipped with pneumatic tires, starting at 0 km / h on snowy road surfaces, icy and snowy road surfaces, and dry road surfaces, 40 km / h (snowy road surface), 10 km, respectively. / H (ice and snow road surface), time until reaching 100 km / h (dry road surface) was measured. In addition, the evaluation result of the comparative example was set to 100, and other evaluation results were shown as an index. An evaluation result shows that traction is so high that a numerical value is large.

(5.1.2) Evaluation of braking force Evaluation method: The time required to start at a predetermined speed and decelerate to a predetermined speed in a vehicle equipped with each pneumatic tire was measured. Specifically, on the road surface on snow, the vehicle started at 30 km / h and measured the time to reach 5 km / h. On the snow and ice road surface, the vehicle started at 10 km / h and measured the time to reach 0 km / h. On the dry road surface, the vehicle started at 80 km / h and measured the time to reach 0 km / h. In addition, the evaluation result of the comparative example was set to 100, and other evaluation results were shown as indexes. An evaluation result shows that braking force is excellent, so that a numerical value is large.

(5.1.3) Evaluation of ride comfort Evaluation method: Each pneumatic tire was mounted on a vehicle, and the evaluation was performed based on the feeling of the driver when traveling on a general road. In addition, the evaluation result of the comparative example was set to 100, and other evaluation results were shown as an index. An evaluation result shows that riding comfort is excellent, so that a numerical value is large.

(5.2) Evaluation Results The evaluation results of each pneumatic tire will be described with reference to Table 1.

  The pneumatic tires according to Examples 1 and 2 were shown to be superior to the pneumatic tire according to the comparative example in all of traction, braking force, and riding comfort.

(6) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. should not do. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, the embodiment of the present invention can be modified as follows. In the embodiment described above, the circumferential sipe (the first circumferential sipe 50, the first circumferential sipe 54, and the second circumferential sipe 52) is formed in the inner block 20, the inner block 22, and the outer block 28. Not limited to this, it may be formed in another block according to required performance.

  In the embodiment described above, the circumferential sipe (the first circumferential sipe 50, the first circumferential sipe 54, the second circumferential direction) is added to all of the plurality of inner blocks 20, inner blocks 22, and outer blocks 28 arranged in the tire circumferential direction TC. For example, a block in which a circumferential sipe is formed and a block in which no circumferential sipe is formed are repeated for each block along the tire circumferential direction TC. It may be arranged. Further, the circumferential sipe (the first circumferential sipe 50, the first circumferential sipe 54, and the second circumferential sipe 52) is formed at the same position in the tread width direction TW in blocks adjacent to the tire circumferential direction TC. However, the present invention is not limited to this, and it may be formed by periodically changing the position in the tread width direction TW in the tire circumferential direction TC.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  CL ... tire equator line, G ... ground contact surface, TC ... tire circumferential direction, TD ... tire radial direction, TW ... tread width direction, 1 ... pneumatic tire, 10 ... tread part, 20, 20A, 22 ... inner block, 24 , 26 ... block, 28, 28A ... outer block, 40, 42, 44, 46 ... circumferential groove, 50, 50A, 54 ... first circumferential sipe, 52, 52A ... second circumferential sipe, 60, 62, 64, 66, 68 ... transverse groove, 100, 100A, 102, 102A ... width direction sipe, 110 ... bottom, 112, 112A, 124 ... kick side bottom, 114, 126 ... tread side bottom, 116 ... raised bottom, 120 ... bottom , 122, 122A ... bottom

Claims (3)

A plurality of blocks defined by a circumferential groove extending along the tire circumferential direction and a lateral groove extending along the tread width direction are provided, and a widthwise sipe extending zigzag along the tread width direction is formed in the block. And at least one end of the width direction sipe is a tire communicating with the circumferential groove at an end portion along the tread width direction of the block,
The block is an inner block provided on the inner side when the vehicle is mounted,
Including an outer block provided outside when the vehicle is installed than the inner block;
The inner block has a first circumferential sipe that extends along the tire circumferential direction and has a groove depth shallower than the widthwise sipe and has a groove depth shallower on the center side of the inner block in the tire circumferential direction. Formed,
The outer block has a second circumferential sipe extending along the tire circumferential direction and having a groove depth shallower than that of the widthwise sipe and having a groove depth shallower at both ends of the outer block in the tire circumferential direction. Tire formed.   The tire according to claim 1, wherein the groove depth of the first circumferential sipe is deeper on the stepping side than on the kicking side in the tire circumferential direction.   The tire according to claim 1 or 2, wherein the groove depth of the second circumferential sipe is deeper on the stepping side than on the kicking side in the tire circumferential direction.

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