JP2020090121A - tire - Google Patents

Abstract

To provide a tire that can exert excellent on-ice and on-snow performance without deteriorating abrasion resistance.SOLUTION: The tire includes a tread part 2, and the tread part 2 includes at least one first block 16. The first block 16 includes a first vertical edge 16a and a second vertical edge 16b, a first sipe 21, a second sipe 22, and a third sipe 23. The third sipe 23 includes a first part 26 extending in a tire shaft direction from the first vertical edge 16a, a second part 27 extending in the tire shaft direction from the second vertical edge 16b and a third part 28 extending at an angle of 5° or less with respect to a tire circumferential direction between the first part 26 and the second part 27.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tire, and more particularly to a tire having a block in which a sipe is provided in a tread portion.

Patent Document 1 below proposes a tire in which a middle block is provided with a hook-shaped middle sipe as a tire suitable for traveling on an ice and snow road.

JP, 2018-114846, A

Generally, a sipe provided on a block provides frictional force on ice and snow roads due to its edge component, while lowering the rigidity (for example, shear rigidity or axial rigidity) of the block, and thus the abrasion resistance of the block. Tends to decrease. Therefore, regarding a tire having a block provided with sipes, it has been required to improve the performance on ice and snow without reducing the wear resistance.

The present invention has been devised in view of the above problems, and a main object of the present invention is to provide a tire capable of exhibiting excellent on-snow and snow performance without lowering wear resistance.

The present invention is a tire including a tread portion, wherein the tread portion includes at least one first block, and the first block includes a first vertical edge and a second vertical edge that extend in a tire circumferential direction on both sides of a tread surface. An edge, a first sipe extending from the first vertical edge and interrupting in the first block, a second sipe extending from the second vertical edge and interrupting in the first block, and the first vertical edge to the A third portion extending to a second vertical edge, the third sipe including a first portion extending in the tire axial direction from the first vertical edge, and a second portion extending in the tire axial direction from the second vertical edge. , A third portion extending between the first portion and the second portion at an angle of 5° or less with respect to the tire circumferential direction.

In the tire of the present invention, it is desirable that the third portion extends parallel to the tire circumferential direction.

In the tire of the present invention, the depth of the third portion is preferably smaller than the depth of the first portion and the depth of the second portion.

In the tire of the present invention, the first vertical edge includes three edge pieces divided into the first sipe and the third sipe, and each of the three edge pieces of the first vertical edge has a tire circumference. The length in the direction is preferably 0.20 to 0.40 times the length in the tire circumferential direction of the first vertical edge.

In the tire of the present invention, the second vertical edge includes three edge pieces divided into the second sipe and the third sipe, and each of the three edge pieces of the second vertical edge is a tire circumference. The length in the direction is preferably 0.20 to 0.40 times the length in the tire circumferential direction of the second vertical edge.

In the tire of the present invention, the first sipe is arranged on one side of the third sipe in the tire circumferential direction, and the second sipe is arranged on the other side of the third sipe in the tire circumferential direction. Is desirable.

In the tire of the present invention, the tread portion includes a plurality of the first blocks arranged in the tire circumferential direction between the tire equator and a tread end, and a plurality of lateral grooves that partition the plurality of first blocks, It is preferable that at least one of the lateral grooves has a tie bar whose bottom surface is raised at an end on the tire equator side.

In the tire of the present invention, the depth from the tread surface of the first block to the outer surface of the tie bar is preferably 0.60 to 0.80 times the maximum depth of the lateral groove.

In the tire of the present invention, the tread portion includes two first blocks adjacent to each other in the tire circumferential direction, a lateral groove between the two first blocks, and one side of the two first blocks in the tire axial direction. It is preferable that the land portion has a recess in the side wall on the side of the two first blocks, and the recess overlaps a region in which the lateral groove extends in the length direction. ..

In the tire of the present invention, a mounting position on a vehicle is designated, the tread portion includes a first tread end located outside the vehicle when the vehicle is mounted, and the first block includes a tire equator and the first tread end. It is desirable that it is provided between and.

The tread portion of the tire of the present invention includes at least one first block. The first block includes a first vertical edge and a second vertical edge that extend in the tire circumferential direction on both sides of a tread surface, a first sipe that extends from the first vertical edge and is interrupted in the first block, and the second vertical edge. A second sipe that extends from an edge and is interrupted in the first block, and a third sipe that extends from the first vertical edge to the second vertical edge are included.

Since the first sipe and the second sipe are interrupted in the first block, the decrease in rigidity of the first block is suppressed, the wear resistance there is maintained, and the performance on snow and snow is improved. Since the third sipe extends from the first vertical edge to the second vertical edge, it is possible to provide a large edge length and further improve the performance on ice and snow.

The third sipe has a first portion extending in the tire axial direction from the first vertical edge, a second portion extending in the tire axial direction from the second vertical edge, and between the first portion and the second portion. And a third portion extending at an angle of 5° or less with respect to the tire circumferential direction. In such a third sipe, when the sipe walls of the third portion come into contact with each other, the frictional force makes it difficult for the first portion and the second portion to open. Such an effect can effectively suppress the deformation of the first block in the tire circumferential direction and further improve the wear resistance.

It is a development view of the tread portion of the tire of one embodiment of the present invention. It is an enlarged view of the 1st middle land part, the 2nd middle land part, and the crown land part of FIG. It is an enlarged view of the 1st block of FIG. It is the sectional view on the AA line of FIG. It is an enlarged view of the 1st shoulder land part of FIG. It is an enlarged view of the 2nd shoulder land part of FIG. It is an enlarged view of the 1st middle land part of the tire of a comparative example.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a development view of a tread portion 2 of a tire 1 showing an embodiment of the present invention. The tire 1 of the present embodiment is preferably used, for example, as a pneumatic tire for passenger cars. However, the present invention is not limited to such an aspect, and may be used for a heavy-duty pneumatic tire or a non-pneumatic tire in which the inside of the tire is not filled with pressurized air.

As shown in FIG. 1, the tire 1 of the present invention has a tread portion 2 in which a mounting direction in a vehicle is designated. The tread portion 2 has a first tread end Te1 located outside the vehicle when the tire 1 is mounted on the vehicle, and a second tread end Te2 located inside the vehicle when mounted on the vehicle. The direction of attachment to the vehicle is displayed, for example, in characters or symbols on the sidewall portion (not shown).

In the case of a pneumatic tire, the first tread end Te1 and the second tread end Te2 are the outermost ground contact positions in the tire axial direction when the normal load is applied to the tire 1 in the normal state and the tire 1 comes in contact with the plane at a camber angle of 0°. is there. The normal state is a state in which the tire is assembled to the regular rim, the regular internal pressure is filled, and there is no load. In the present specification, unless otherwise specified, the dimensions and the like of each part of the tire are values measured in the normal state.

The "regular rim" is a rim that is defined for each tire in the standard system including the standard on which the tire is based. For example, "standard rim" for JATMA, "Design Rim" for TRA, and ETRTO. If there is "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. For JATMA, "maximum air pressure" and for TRA, the table "TIRE LOAD LIMITS AT The maximum value described in "VARIOUS COLD INFLATION PRESSURES" is "INFLATION PRESSURE" for ETRTO.

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

The tread portion 2 has a plurality of main grooves 3 continuously extending in the tire circumferential direction between a first tread end Te1 and a second tread end Te2, and a plurality of land portions 4 divided into the main grooves 3. ..

The main groove 3 includes, for example, a first shoulder main groove 5, a second shoulder main groove 6, a first crown main groove 7 and a second crown main groove 8. The first shoulder main groove 5 is provided between the first tread end Te1 and the tire equator C. The second shoulder main groove 6 is provided between the second tread end Te2 and the tire equator C. The first crown main groove 7 is provided between the first shoulder main groove 5 and the tire equator C. The second crown main groove 8 is provided between the second shoulder main groove 6 and the tire equator C.

The distance L1 in the tire axial direction from the tire equator C to the groove center line of the first shoulder main groove 5 or the second shoulder main groove 6 is preferably, for example, 0.20 to 0.35 times the tread width TW. .. The distance L2 in the tire axial direction from the tire equator C to the groove center line of the first crown main groove 7 or the second crown main groove 8 is preferably, for example, 0.05 to 0.15 times the tread width TW. .. The tread width TW is a tire axial direction distance from the first tread end Te1 to the second tread end Te2 in the normal state.

Each main groove 3 of the present embodiment extends, for example, in a straight line in parallel with the tire circumferential direction. Each main groove 3 may extend, for example, in a wave shape.

The groove width W1 of each main groove 3 is preferably, for example, 4.0% to 8.0% of the tread width TW. The depth of each main groove 3 is preferably, for example, 5 to 10 mm in the case of a pneumatic tire for passenger cars.

The land portion 4 includes a first middle land portion 11, a second middle land portion 12, a first shoulder land portion 13, a second shoulder land portion 14, and a crown land portion 15. That is, the tread portion 2 of the present embodiment has a so-called five-rib pattern formed of the above-mentioned four main grooves 3 and five land portions 4. However, the present invention is not limited to such an aspect.

The first middle land portion 11 is divided between the first shoulder main groove 5 and the first crown main groove 7. The second middle land portion 12 is divided between the second shoulder main groove 6 and the second crown main groove 8. The first shoulder land portion 13 is sectioned between the first shoulder main groove 5 and the first tread end Te1. The second shoulder land portion 14 is sectioned between the second shoulder main groove 6 and the second tread end Te2. The crown land portion 15 is divided between the first crown main groove 7 and the second crown main groove 8.

FIG. 2 shows an enlarged view of the first middle land portion 11, the second middle land portion 12, and the crown land portion 15. As shown in FIG. 2, the width W2 of the first middle land portion 11 in the tire axial direction, the width W3 of the second middle land portion 12 in the tire axial direction, and the width W4 of the crown land portion 15 in the tire axial direction are It is desirable that each of the widths is 0.10 to 0.25 times the tread width TW.

The first middle land portion 11 includes at least one first block 16. The first middle land portion 11 of the present embodiment includes, for example, a plurality of first blocks 16 divided into a plurality of lateral grooves (hereinafter, referred to as first middle lateral grooves 17).

An enlarged view of the first block 16 is shown in FIG. As shown in FIG. 3, the first block 16 includes a first vertical edge 16a and a second vertical edge 16b extending in the tire circumferential direction on both sides of the tread, a first sipe 21, a second sipe 22 and a third sipe 23. Includes and. In the present specification, “sipe” is defined as a notch having a width of 1.0 mm or less. The depth of the sipe is preferably 0.30 to 0.70 times the depth of the main groove 3, for example.

The first sipe 21 extends from the first vertical edge 16 a and is interrupted in the first block 16. The second sipe 22 extends from the second vertical edge 16b and is interrupted in the first block 16. The third sipe 23 extends from the first vertical edge 16a to the second vertical edge 16b.

The first sipe 21 and the second sipe 22 are interrupted in the first block 16, so that the rigidity of the first block 16 is prevented from decreasing and the wear resistance thereof is maintained, while improving the performance on ice and snow. Since the third sipe 23 extends from the first vertical edge 16a to the second vertical edge 16b, it is possible to provide a large edge length and further improve the performance on ice and snow.

The third sipe 23 includes a first portion 26, a second portion 27, and a third portion 28. The first portion 26 extends in the tire axial direction from the first vertical edge 16a. The second portion 27 extends in the tire axial direction from the second vertical edge 16b. The third portion 28 extends between the first portion 26 and the second portion 27 at an angle of 5° or less with respect to the tire circumferential direction.

In such a third sipe 23, when the sipe walls of the third portion 28 come into contact with each other, the frictional force makes it difficult for the first portion 26 and the second portion 27 to open. Such an effect can effectively suppress the deformation of the first block in the tire circumferential direction and enhance the wear resistance.

In the first block 16 of the present embodiment, the first vertical edge 16a and the second vertical edge 16b extend in parallel. Further, in the first block 16, two horizontal edges 16c extending between the first vertical edge 16a and the second vertical edge 16b extend in parallel with each other.

The first sipe 21 is, for example, arranged on one side (the upper side in FIG. 3) of the third sipe 23 in the tire circumferential direction. The 1st sipe 21 inclines in the 1st direction (it goes up to the right in Drawing 3) to the tire axis direction, for example. The angle of the first sipe 21 with respect to the tire axial direction is, for example, 20 to 30°.

The length L3 of the first sipe 21 in the tire axial direction is, for example, 0.20 to 0..0 of the width W5 of the first block 16 in the tire axial direction (the same as the width W2 of the first middle land portion 11). 35 times. Such a first sipe 21 can exhibit excellent on-ice and snow performance while maintaining wear resistance. In addition, in this specification, each length of the sipe shall be measured at the center line of the sipe.

The second sipe 22 is arranged, for example, on the other side (the lower side in FIG. 3) of the third sipe 23 in the tire circumferential direction. The second sipe 22 has substantially the same configuration as the first sipe 21. Therefore, the configuration of the first sipe 21 described above can be applied to the second sipe 22.

The first portion 26 of the third sipe 23 is, for example, inclined in the same direction as the first sipe 21 with respect to the tire axial direction. The angle of the first portion 26 with respect to the tire axial direction is, for example, 20 to 30°. As a more desirable aspect, the first portion 26 of the present embodiment extends parallel to the first sipe 21. As a result, uneven wear of the first block 16 is suppressed.

The length L4 of the first portion 26 in the tire axial direction is preferably larger than the length L3 of the first sipe 21 in the tire axial direction, for example. The length L4 of the first portion 26 of the present embodiment is, for example, 0.40 to 0.55 times the width W5 of the first block 16 in the tire axial direction.

The second portion 27 of the third sipe 23 is, for example, inclined in the same direction as the second sipe 22 with respect to the tire axial direction. The angle of the second portion 27 with respect to the tire axial direction is, for example, 20 to 30°. As a more desirable aspect, the second portion 27 of the present embodiment extends parallel to the second sipe 22.

The length L5 of the second portion 27 in the tire axial direction is, for example, larger than the length of the second sipe 22 in the tire axial direction. In a more desirable aspect, the length L5 of the second portion 27 in the tire axial direction is larger than the length L4 of the first portion 26 in the tire axial direction, for example. The length L5 of the second portion 27 of the present embodiment is, for example, 0.45 to 0.60 times the width W5 of the first block 16 in the tire axial direction. Since the ground pressure larger than that of the first portion 26 acts on the second portion 27, the above-mentioned arrangement of the sipes can further improve the performance on ice and snow.

The third portion 28 is preferably arranged, for example, in a central region when the first block 16 is divided into three equal parts in the tire axial direction. The distance in the tire axial direction between the third portion 28 and the center position of the first block 16 in the tire axial direction is preferably, for example, less than 10% of the width W5 of the first block 16 in the tire axial direction. Further, it is desirable that the third portion 28 be located slightly on the first tread end Te1 side with respect to the center position of the first block 16. The third portion 28 as described above can provide the frictional force in the tire axial direction on the icy and snowy road while suppressing the uneven wear of the first block 16.

The third portion 28 preferably extends, for example, parallel to the tire circumferential direction. Such a third portion 28 can provide a large frictional force in the tire axial direction on a snowy road.

In order to enhance the wear resistance and the performance on snow and ice in a good balance, the length L7 of the third portion 28 in the tire circumferential direction is, for example, 0.50 times or less than the length L6 of the first vertical edge 16a in the tire circumferential direction. Is desirable, and specifically, it is desirable to be 0.25 to 0.40 times.

The depth of the third portion 28 is preferably smaller than the depth of the first portion 26 and the depth of the second portion 27. Specifically, the depth of the third portion 28 is preferably 0.40 to 0.60 times the depth of the first portion 26 or the second portion 27. Such a third portion 28 can further suppress uneven wear of the first block 16.

The first vertical edge 16a includes three edge pieces 29a divided into a first sipe 21 and a third sipe 23. Each of the three edge pieces 29a of the first vertical edge 16a has, for example, a length in the tire circumferential direction of 0.20 to 0.40 times the length L6 of the first vertical edge 16a in the tire circumferential direction. As a result, uneven wear of each edge piece 29a is suppressed.

Similarly, the second vertical edge 16b includes three edge pieces 29b divided into a second sipe 22 and a third sipe 23. Each of the three edge pieces 29b of the second vertical edge 16b has a tire circumferential direction length that is, for example, 0.20 to 0.40 times the tire circumferential direction length of the second vertical edge 16b.

In the present invention, the above-mentioned first block 16 is not limited to the one arranged in the first middle land portion 11, and may be arranged in another land portion.

As shown in FIG. 2, the first middle lateral groove 17 is inclined in the first direction with respect to the tire axial direction, for example. The angle θ1 of the first middle lateral groove 17 with respect to the tire axial direction is, for example, 20 to 30°. The first middle lateral groove 17 of the present embodiment extends linearly with a constant groove width. However, the present invention is not limited to such an aspect.

It is desirable that the first middle lateral groove 17 has, for example, an enlarged groove width at the end portion in the tire axial direction. The first middle lateral groove 17 as described above can strongly press the snow in the grooves together with the respective main grooves and exert a large snow column shearing force when traveling on ice and snow.

FIG. 4 shows a sectional view taken along the line AA of the first middle lateral groove 17. As shown in FIG. 4, at least one of the first middle lateral grooves 17 preferably has a tie bar 30 whose bottom surface is raised at the end portion on the tire equator C side. Such a tie bar 30 can prevent the first middle lateral groove 17 from opening excessively, and can exhibit excellent wear resistance and performance on ice and snow.

The depth d2 from the tread surface of the first block 16 to the outer surface of the tie bar 30 is preferably 0.50 to 0.80 times the maximum depth d1 of the first middle lateral groove 17. Such a tie bar 30 can improve the wear resistance and the performance on snow and ice in a well-balanced manner.

From the same viewpoint, the length L8 of the tie bar 30 in the tire axial direction is preferably 0.10 to 0.30 times the width W5 (shown in FIG. 2) of the first block 16 in the tire axial direction.

As shown in FIG. 2, the second middle land portion 12 includes, for example, a plurality of second blocks 31 divided into a plurality of second middle lateral grooves 32.

The second middle lateral groove 32 includes, for example, a first groove portion 32a that communicates with the second crown main groove 8 and a second groove portion 32b that communicates with the second shoulder main groove 6. The first groove portion 32a and the second groove portion 32b are continuous in the vicinity of the center portion of the second middle land portion 12 in the tire axial direction and are displaced in the tire circumferential direction. Such a second middle lateral groove 32 can generate a hard snow column in the groove and can provide a large snow column shearing force.

Each of the first groove portion 32a and the second groove portion 32b is inclined in the first direction with respect to the tire axial direction. The angle of the first groove portion 32a and the second groove portion 32b with respect to the tire axial direction is preferably, for example, 20 to 30°.

The second block 31 is provided with, for example, two middle sipes 35 extending from the second crown main groove 8 to the second shoulder main groove 6. The middle sipe 35 includes, for example, two inclined portions 35a that are inclined and extend in the first direction, and a vertical portion 35b between them. As a result, the middle sipe 35 is bent like a staircase. Such a middle sipe 35 also provides a frictional force in the tire axial direction, and is useful for improving turning performance on an ice and snowy road.

The vertical portions 35b of the two middle sipes 35 are preferably displaced from each other in the tire axial direction. Such a middle sipe 35 can suppress uneven wear of the second block 31. Further, it is desirable that the length of the vertical portion 35b in the tire circumferential direction be smaller than the length of the third portion 28 of the third sipe 23 in the tire circumferential direction. As a result, the progress of wear of the first block 16 and the second block 31 having different magnitudes of the ground pressure acting thereon becomes uniform.

The second block 31 includes, for example, recesses 36 provided on the sidewalls on both sides. The middle sipes 35 are in communication with the respective ends of the recess 36 in the tire circumferential direction. Such a recess 36 can generate a large snow pillar together with the main groove, and can prevent the snow pillar from clogging the main groove.

The crown land portion 15 is provided with a plurality of interrupted grooves 45 and a plurality of crown sipes 40. The discontinuity groove 45 and the crown sipe 40 are inclined, for example, in a second direction (downward to the right in FIG. 2) opposite to the first direction with respect to the tire axial direction.

The interrupted groove 45 extends from the second crown main groove 8 and is interrupted in the crown land portion 15, for example. The length L9 of the interrupted groove 45 in the tire axial direction is preferably, for example, 0.30 to 0.45 times the width W4 of the crown land portion 15 in the tire axial direction.

The crown sipe 40 includes a first crown sipe 41, a second crown sipe 42, a third crown sipe 43, and a fourth crown sipe 44.

The first crown sipe 41 extends, for example, from the end of the interrupted groove 45 to the first crown main groove 7. The first crown sipe 41 has, for example, a gently sloping portion 41a that communicates with the first crown main groove 7, and a steeply sloping portion 41b that communicates between the gently sloping portion 41a and the interrupted groove 45. The angle of the gently inclined portion 41a with respect to the tire axial direction is, for example, 20 to 30°. The angle of the steep slope portion 41b with respect to the tire axial direction is larger than the angle of the gentle slope portion 41a with respect to the tire axial direction. The angle of the steep slope 41b is preferably 70 to 80°, for example. The first crown sipe 41 as described above is useful for improving the turning performance on the icy and snowy road.

The second crown sipe 42 extends from the first crown main groove 7 and is interrupted in the crown land portion 15, for example. The second crown sipe 42 of the present embodiment has the same configuration as the gently sloped portion 41a of the first crown sipe 41. Therefore, the configuration of the gently sloped portion 41a described above can be applied to the second crown sipe 42.

Each of the third crown sipe 43 and the fourth crown sipe 44 extends from the second crown main groove 8 and is discontinued in the crown land portion 15. It is desirable that the fourth crown sipe 44 be discontinuous on the second crown main groove 8 side with respect to the third crown sipe 43, for example. The third crown sipe 43 and the fourth crown sipe 44 can improve the performance on ice and snow while maintaining the rigidity of the crown land portion 15.

The distance in the tire circumferential direction between the third crown sipe 43 and the fourth crown sipe 44 is smaller than the distance in the tire circumferential direction between the gently sloped portion 41a of the first crown sipe 41 and the second crown sipe 42. Is desirable.

The second crown sipe 42, the third crown sipe 43, and the fourth crown sipe 44 are each preferably inclined at an angle of 20 to 30° with respect to the tire axial direction. In this embodiment, these sipes are provided in parallel with each other.

The gently-sloped portion 41a of the first crown sipe 41, the second crown sipe 42, the third crown sipe 43, and the fourth crown sipe 44 each have a tire axial length equal to the tire axial width of the crown land portion 15. It is 0.50 times or less, preferably 0.20 to 0.45 times. Such sipes can enhance wear resistance and performance on ice and snow in a well-balanced manner.

The crown land portion 15 includes a recess 46 on its side wall. The recess 46 of the crown land portion 15 includes a first recess 46a on the side of the first middle land portion 11 where the first blocks 16 are lined up and a second recess 46b on the side of the second middle land portion 12 side.

It is desirable that the first recess 46a overlaps, for example, a region in which the first middle lateral groove 17 is extended in the length direction thereof. The distance L12 in the tire circumferential direction between the end of the first recess 46a and the second portion 27 of the third sipe 23 is, for example, the length L6 (shown in FIG. 3) of the first vertical edge 16a in the tire circumferential direction. It is 0.10 to 0.20 times. Such a first concave portion 46a can generate a solid snow pillar together with the first middle lateral groove 17 and the first crown main groove 7 during traveling on an icy snow road.

The length of the first recess 46a in the tire circumferential direction is preferably larger than the length of the edge piece 29b between the second sipe 22 and the third sipe 23 in the tire circumferential direction, for example. Further, it is desirable that the length of the first recess 46a be smaller than the length of the second vertical edge 16b in the tire circumferential direction.

The 1st crown sipe 41 and the 2nd crown sipe 42 are open for free passage, for example to the 1st crevice 46a of this embodiment. The first crown sipe 41 and the second crown sipe 42 communicate with, for example, an end portion of the first recess 46a in the tire circumferential direction. As a result, the snow hardened in the first recess 46a is easily discharged, and the excellent performance on ice and snow is continuously exhibited.

The length of the second recess 46b in the tire circumferential direction is preferably smaller than the length of the first recess 46a in the tire circumferential direction, for example. In the present embodiment, the length of the second recess 46b is the same as the length of the recess 36 provided in the second block 31 in the tire circumferential direction.

It is desirable that the region where the second recess 46b is extended in the tire axial direction overlaps at least a part of the recess 36 provided in the second block 31. In the present embodiment, the region overlaps with 50% or less of the length of the concave portion 36 provided in the second block 31 in the tire circumferential direction.

FIG. 5 shows an enlarged view of the first shoulder land portion 13. As shown in FIG. 5, the width W6 of the first shoulder land portion 13 in the tire axial direction is preferably, for example, 0.15 to 0.25 times the tread width TW.

The first shoulder land portion 13 is provided with, for example, a shoulder lateral groove 50, a first connecting sipe 51 connected to the shoulder lateral groove 50, and a first sipe group 52 including two sipes. The shoulder lateral groove 50, the first connecting sipe 51, and the first sipe group 52 are provided alternately in the tire circumferential direction.

The shoulder lateral groove 50 extends from the first tread end Te1 and is interrupted in the first shoulder land portion 13, for example. The length L10 of the shoulder lateral groove 50 in the tire axial direction is, for example, 0.75 to 0.90 times the width W6 of the first shoulder land portion 13 in the tire axial direction. Such a shoulder lateral groove 50 can improve the performance on snow and ice while maintaining the rigidity of the first shoulder land portion 13.

The shoulder lateral groove 50 includes, for example, a portion inclined in the first direction in a region including an inner end portion in the tire axial direction. Such a shoulder lateral groove 50 is useful for improving turning performance on an ice and snowy road.

The first connection sipe 51 extends from the inner end of the shoulder lateral groove 50 to the first shoulder main groove 5, for example. The first connection sipes 51 prevent the shoulder lateral grooves 50 from being clogged with snow.

The first sipe group 52 includes, for example, an inner portion 52a that extends from the first shoulder main groove 5 and is interrupted in the first shoulder land portion 13, and an outer portion 52b that extends from the first tread end Te1 and is interrupted in front of the inner portion 52a. Includes and. The distance between the inner portion 52a and the outer portion 52b is, for example, 1.0 to 3.0 mm. The first sipe group 52 as described above can improve the performance on ice and snow while maintaining the wear resistance of the first shoulder land portion 13.

The first sipe group 52 preferably includes, for example, a portion extending in a zigzag shape. In such a first sipe group 52, since the sipe walls facing each other are in contact with each other so as to mesh with each other, it is possible to maintain the rigidity of the first shoulder land portion 13 and suppress deterioration of wear resistance.

FIG. 6 shows an enlarged view of the second shoulder land portion 14. As shown in FIG. 6, the width W7 of the second shoulder land portion 14 in the tire axial direction is preferably, for example, 0.15 to 0.25 times the tread width TW.

In the second shoulder land portion 14, for example, a shoulder through groove 56 and a shoulder discontinuity groove 57 are alternately provided in the tire circumferential direction. The shoulder through groove 56 extends from the second tread end Te2 to the second shoulder main groove 6. The shoulder interruption groove 57 extends from the second tread end Te2 and is interrupted in the second shoulder land portion 14. The length L11 of the shoulder interruption groove 57 in the tire axial direction is, for example, 0.80 to 0.95 times the width W7 of the second shoulder land portion 14 in the tire axial direction. The shoulder through groove 56 and the shoulder interrupted groove 57 help to improve wear resistance and performance on snow and ice in a well-balanced manner.

It is desirable that the second shoulder land portion 14 of the present embodiment is provided with a second connection sipe 58 that extends from the end portion of the shoulder interruption groove 57 to the second shoulder main groove 6.

A second sipe group 59 including two sipes is provided between the shoulder through groove 56 and the shoulder interrupted groove 57. The second sipe group 59 includes, for example, an inner portion 59a that extends from the second shoulder main groove 6 and is interrupted in the second shoulder land portion 14, and an outer portion 59b that extends from the second tread end Te2 and is interrupted in front of the inner portion 59a. Includes and. The distance between the inner portion 59a and the outer portion 59b is, for example, 1.0 to 3.0 mm. Further, the second sipe group 59 preferably includes, for example, a portion extending in a zigzag shape.

A recess 60 is preferably provided on the side wall of the second shoulder land portion 14 on the main groove side. It is desirable that the recess 60 of the second shoulder land portion 14 overlaps a region in which the recess 36 provided on the side wall of the second block 31 on the second shoulder main groove 6 side is extended in the tire axial direction. In the present embodiment, the region overlaps with 50% or more of the length of the recess 60 of the second shoulder land portion 14 in the tire circumferential direction. Such a disposition of the recessed portion 60 can generate a hard snow column in both the main grooves when traveling on a snowy road.

Although the tire according to the embodiment of the present invention has been described in detail above, the present invention is not limited to the above specific embodiment, and may be carried out in various modes.

A size 225/65R17 tire having the basic pattern of FIG. 1 was prototyped. As a comparative example, a tire having the first middle land portion a shown in FIG. 7 was prototyped. As shown in FIG. 7, in the tire of the comparative example, the block b arranged in the first middle land portion a is provided with two sipes c that are inclined with respect to the tire axial direction and extend linearly. There is. The pattern of the tire of the comparative example is substantially the same as that shown in FIG. 1 except for the above matters. Each test tire was tested for performance on snow and snow and abrasion resistance. The common specifications and test methods for each test tire are as follows.
Mounting rim: 17 x 6.5J
Tire pressure: front wheel 230kPa, rear wheel 230kPa
Test vehicle: Displacement 2000cc, 4WD vehicle Tire mounting position: All wheels

<Performance on ice and snow>
On a snowy road, the test vehicle was accelerated from 8 km/h to a speed of 32 km/h, and the traveling distance required for acceleration at this time was measured. The results are shown as an index with the traveling distance of the comparative example being 100, and the smaller the value, the better the performance on ice and snow.

<Abrasion resistance>
A wear energy measuring device was used to measure the wear energy of the first middle land portion. The result is an index with the wear energy of the comparative example being 100, and the smaller the value, the smaller the wear energy and the better the wear resistance.
The test results are shown in Table 1.

As a result of the test, it was confirmed that the tires of Examples exhibited excellent on-snow and snow performance without lowering wear resistance.

2 tread part 16 1st block 16a 1st vertical edge 16b 2nd vertical edge 21 1st sipe 22 2nd sipe 23 3rd sipe 26 1st part 27 2nd part 28 3rd part

Claims (10)

A tire including a tread portion,
The tread portion includes at least one first block,
The first block is
A first vertical edge and a second vertical edge extending in the tire circumferential direction on both sides of the tread,
A first sipe extending from the first vertical edge and interrupting within the first block;
A second sipe extending from the second vertical edge and interrupting within the first block;
A third sipe extending from the first vertical edge to the second vertical edge,
The third sipe is
A first portion extending in the tire axial direction from the first vertical edge;
A second portion extending in the tire axial direction from the second vertical edge;
A third portion extending at an angle of 5° or less with respect to the tire circumferential direction between the first portion and the second portion,
tire. The tire according to claim 1, wherein the third portion extends parallel to the tire circumferential direction. The tire according to claim 1 or 2, wherein the depth of the third portion is smaller than the depth of the first portion and the depth of the second portion. The first vertical edge includes three edge pieces divided into the first sipe and the third sipe,
The tire circumferential direction length of each of the three edge pieces of the first vertical edge is 0.20 to 0.40 times the tire circumferential direction length of the first vertical edge. The tire according to any one of 3 above. The second vertical edge includes three edge pieces divided into the second sipe and the third sipe,
The tire circumferential direction length of each of the three edge pieces of the second vertical edge is 0.20 to 0.40 times the tire circumferential direction length of the second vertical edge. The tire according to any one of 4 above. The first sipe is arranged on one side in the tire circumferential direction of the third sipe,
The tire according to any one of claims 1 to 5, wherein the second sipe is arranged on the other side of the third sipe in the tire circumferential direction. The tread portion includes a plurality of the first blocks arranged in the tire circumferential direction between the tire equator and a tread end, and a plurality of lateral grooves that partition the plurality of first blocks,
7. The tire according to claim 1, wherein at least one of the lateral grooves has a tie bar whose bottom surface is raised at an end portion on the tire equator side. The tire according to claim 7, wherein the depth from the tread surface of the first block to the outer surface of the tie bar is 0.60 to 0.80 times the maximum depth of the lateral groove. The tread portion includes two first blocks adjacent to each other in the tire circumferential direction, a lateral groove between the two first blocks, and a land portion adjacent to one side of the two first blocks in the tire axial direction. Including,
The land portion has a recess on the side wall of the two first blocks,
The tire according to any one of claims 1 to 8, wherein the concave portion overlaps with a region in which the lateral groove is extended in a length direction thereof. The mounting position on the vehicle is specified,
The tread portion includes a first tread end located outside the vehicle when the vehicle is mounted,
The tire according to any one of claims 1 to 9, wherein the first block is provided between a tire equator and the first tread end.

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