tire

Abstract

To provide a tire which can further improve brake performance on a snow ice road at the time of cornering when a tread pattern where blocks having comparatively small contact areas are densely arranged is used.SOLUTION: A tire includes block rows 31 and 32 partitioned by a pair of circumferential direction grooves 41, 42 and 43 extending in a tire circumferential direction. The block rows include a plurality of blocks 100 and 200 partitioned by a plurality of width direction grooves 61 and 62 extending in a tire width direction. Each block of the block rows 31 and 32 is partitioned into a plurality of small blocks 101 and 201 by circumferential direction sipes 120 and 220 and a plurality of width direction sipes 130 and 230. The circumferential direction sipes extend in a tire circumferential direction. The width direction sipes include first width direction sipes 130a and 230a and second width direction sipes 130b and 230b, which extend in different directions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a tire that uses a tread pattern in which blocks with a relatively small contact area are arranged closely together. [Background technology]

[0002] 2. Description of the Related Art Conventionally, for winter tires (hereinafter referred to as tires) suitable for driving on snowy and icy roads, a method has been known that uses a tread pattern in which blocks with a relatively small contact area are densely arranged (Patent Document 1).

[0003] A tread pattern with these small blocks arranged closely together has better contact with icy and snowy roads than blocks of normal size, and can therefore improve driving performance on icy and snowy roads (hereinafter referred to as "ice performance"). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-193202 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned conventional tires still have room for improvement, as follows: Specifically, there is a demand for further improvement in performance on ice, particularly in braking performance on snowy and icy roads during cornering.

[0006] The following disclosure has been made in consideration of these circumstances, and aims to provide a tire that can further improve braking performance on snowy and icy roads when cornering when using a tread pattern in which blocks with relatively small contact areas are arranged closely together. [Means for solving the problem]

[0007] A tire according to one aspect of the present invention includes a plurality of block rows defined by a pair of circumferential grooves extending in a tire circumferential direction, and the block rows include a plurality of blocks defined by a plurality of widthwise grooves extending in a tire width direction. Included in at least one of the plurality of block rows Each of the blocks is divided into a plurality of small blocks by a circumferential sipe extending in the tire circumferential direction and a plurality of widthwise sipes extending in the tire width direction. The circumferential sipes extend along the tire circumferential direction. The widthwise sipes include a first widthwise sipe and a second widthwise sipe extending in different directions from each other. Each of the blocks has a triangular shape in a tread plan view. Each of the small blocks included in each of the blocks also has a triangular shape in a tread plan view. Effect of the Invention

[0008] In the above-mentioned tire, each block included in the block row is divided into small blocks by circumferential sipes extending parallel to the tire circumferential direction and multiple widthwise sipes including first widthwise sipes and second widthwise sipes extending in different directions. In this configuration, each small block supports not only adjacent small blocks in the tire width direction but also adjacent small blocks in the tire circumferential direction during cornering, so that the bending rigidity of each block in the tire width direction is increased. This increased bending rigidity improves the tire's ground contact during braking.

[0009] Therefore, according to the above-mentioned tire, when a tread pattern is used in which blocks with a relatively small contact area are arranged closely together, braking performance on snowy and icy roads during cornering can be further improved. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a plan view of a portion of a tread of a pneumatic tire 10. As shown in FIG. [Diagram 2] FIG. 2 is an enlarged plan view of a portion of the tread 20. As shown in FIG. [Diagram 3] FIG. 3 is a partial cross-sectional view of a block 100 including a circumferential sipe 120 (widthwise sipe 130) taken along the sipe width direction and the tire radial direction TR. [Figure 4]FIG. 4 is a plan view of a portion of a tread of a pneumatic tire 10A according to the second embodiment. [Diagram 5] FIG. 5 is a plan view of a portion of a tread of a pneumatic tire 10B according to the first modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and the description thereof will be omitted as appropriate.

[0012] (1) Overall tire configuration Figure 1 shows ,fruit 1 is a plan view of a portion of a tread of a pneumatic tire 10 according to an embodiment.

[0013] The pneumatic tire 10 is a so-called winter tire that can run on icy and snowy road surfaces, specifically, on icy and snowy road surfaces, and is also called a studless tire. The pneumatic tire 10 may be an all-season tire that can run on non-icy and snowy road surfaces (wet and dry road surfaces) and icy and snowy road surfaces. Alternatively, the pneumatic tire 10 may be a general summer tire instead of a winter tire or an all-season tire.

[0014] Further, the vehicle type on which the pneumatic tire 10 is mounted is not particularly limited, but may be primarily passenger automobiles (which may include SUVs and minivans).

[0015] The pneumatic tire 10 uses a tread pattern in which blocks with a relatively small contact area are densely arranged. Specifically, as shown in Fig. 1, the pneumatic tire 10 includes a plurality of block rows 31, 32 extending in the tire circumferential direction TC. The block rows 31, 32 are defined by a pair of adjacent circumferential grooves 41, 42, 43. The pneumatic tire 10 of this embodiment also includes block rows 33, 34 defined by one circumferential groove (circumferential groove 42 or circumferential groove 43) and the tread end.

[0016] The tread 20 is the portion that comes into contact with the road surface. The tread 20 has a tread pattern formed thereon according to the environment in which the pneumatic tire 10 will be used and the type of vehicle on which the tire will be mounted.

[0017] In the tread 20, a circumferential groove 41 is provided at a position including the tire equator line CL, and a block row 31 and a block row 32 are provided adjacent to the circumferential groove 41.

[0018] Further, a block row 33 is provided on the outer side of the block row 31 in the tire width direction, and a block row 34 is provided on the outer side of the block row 32 in the tire width direction.

[0019] The block row 31 is defined by a pair of circumferential grooves extending in the tire circumferential direction TC, specifically, a circumferential groove 41 and a circumferential groove .

[0020] The block row 32 is defined by a circumferential groove 41 and a circumferential groove 43. Since the block row 33 and the block row 34 are provided in the shoulder region of the tread 20, no circumferential groove is formed on the outer side in the tire width direction.

[0021] (2) Block shape 2 is a partially enlarged plan view of the tread 20. As described above, the tread 20 is provided with a plurality of block rows extending in the tire circumferential direction TC, and each of the block rows includes a plurality of blocks that come into contact with the road surface.

[0022] Specifically, the block row includes a plurality of blocks partitioned by a plurality of widthwise grooves extending in the tire width direction WD. Specifically, the block row 31 includes a block 100, the block row 32 includes a block 200, the block row 33 includes a block 300, and the block row 34 includes a block 400.

[0023] The blocks 100 are partitioned by widthwise grooves 61a, 61b having different inclination directions with respect to the tire width direction WD. Specifically, the block row 31 is partitioned into a plurality of blocks 100 by the widthwise grooves 61a, 61b having different inclination directions being alternately arranged in the circumferential direction TC.

[0024] Similarly, the blocks 200 are partitioned by widthwise grooves 62a, 62b having different inclination directions with respect to the tire width direction WD. The block row 32 is partitioned into a plurality of blocks 200 by alternately arranging the widthwise grooves 62a, 62b having different inclination directions in the circumferential direction TC. With this configuration, each of the blocks 100, 200 in this embodiment has a triangular shape in a tread plan view.

[0025] The block 300 is divided by a width direction groove 63. The block 400 is divided by a width direction groove 64.

[0026] Each block 100 is divided into a plurality of small blocks 101 by circumferential sipes 120 extending in the tire circumferential direction TC and widthwise sipes 130 extending in the tire widthwise direction WD.

[0027] Specifically, the block 100 is divided into four small blocks 101 by one circumferential sipe 120 extending along the tire circumferential direction TC and two widthwise sipes 130 extending in mutually different directions.

[0028] In this embodiment, the small blocks 101 have a triangular columnar shape in a plan view of the tread.

[0029] In this embodiment, the tire circumferential direction 120 is formed parallel to the tire circumferential direction TC. Each end of the circumferential sipe 120 communicates with one of the widthwise grooves 61. Specifically, the end of the circumferential sipe 120 communicates with the widthwise groove 61a and the widthwise groove 61b adjacent to the block 100. The circumferential sipe 120 is provided so as to directly connect the widthwise grooves 61a and 61b without communicating with the circumferential grooves 41 and 42 at an intermediate portion as well.

[0030] Moreover, at least one end of the widthwise sipe 130 communicates with either the circumferential groove 41 or 42. In this embodiment, the widthwise sipe 130 includes a first widthwise sipe 130a having one end communicating with the circumferential groove 41 or the circumferential direction 42 and the other end communicating with a position in the widthwise groove 61a where the circumferential sipe 120 communicates, and a second widthwise sipe 130b having one end communicating with the circumferential groove 41 or the circumferential direction 42 and the other end communicating with a position in the widthwise groove 61b where the circumferential sipe 120 communicates.

[0031] Furthermore, in this embodiment, the widthwise grooves 61a, 61b and the widthwise sipes 130a, 130b are inclined with respect to the tire width direction WD. Furthermore, the widthwise grooves 61a and the widthwise sipes 130b are parallel to each other in the tread surface view, and the widthwise grooves 61b and the widthwise sipes 130b are parallel to each other in the tread surface view. In other words, the inclination angle of the widthwise grooves 61a (61b) with respect to the tire width direction WD is the same as the inclination angle of the widthwise sipes 130b (130a) with respect to the tire width direction WD.

[0032] In this embodiment, the block 200 has a shape symmetrical to the block 100 with respect to the equator line CL in a plan view of the tread.

[0033] As shown in FIG. 1, in a pneumatic tire 10, a block row 31 including a triangular block 100 having a triangular columnar small block 101 and a block row 32 including a triangular block 200 having a triangular columnar small block 201 are provided only in a center portion CT partitioned by a pair of circumferential grooves 42, 43 located on the outermost sides in the tire width direction and arranged on either side of the tire equator line CL.

[0034] The block 300 is divided into six small blocks 301 each having a rectangular shape in a tread plan view by one circumferential sipe 320 and two widthwise sipes 330 .

[0035] An end portion on the inner side in the tire width direction of the lateral sipe 330 communicates with the circumferential groove 42 , and an end portion of the circumferential sipe 320 communicates with a lateral groove 63 formed adjacent to the block 300 .

[0036] Further, the widthwise grooves 63 and the widthwise sipes 330 are inclined with respect to the tire width direction WD. As shown in Fig. 1, a portion of the widthwise grooves 63 and the widthwise sipes 330 on the circumferential groove 42 side may be more inclined than the other portions.

[0037] Each block 400 is also divided into six small blocks 401 each having a rectangular shape in a plan view of the tread by one circumferential sipe 420 and two widthwise sipes 430 .

[0038] An end portion on the inner side in the tire width direction of the lateral sipe 430 communicates with the circumferential groove 43 , and an end portion of the circumferential sipe 420 communicates with a lateral groove 64 formed adjacent to the block 400 .

[0039] Further, the widthwise grooves 64 and the widthwise sipes 430 are inclined with respect to the tire width direction WD. As shown in Fig. 1, a portion of the widthwise grooves 64 and the widthwise sipes 430 on the circumferential groove 43 side may be more inclined than the other portions.

[0040] As shown in FIG. 1, the block 300 and the block 400 have shapes that are point symmetrical with each other.

[0041] (3) Cross-sectional shape of circumferential sipes and widthwise sipes FIG. 3 is a partial cross-sectional view of a block 100 including a circumferential sipe 120 or a widthwise sipe 130, taken along the sipe width direction and the tire radial direction TR.

[0042] At least the circumferential sipes 220 formed in the block 200 have the same cross-sectional shape as the circumferential sipes 120 formed in the block 100. The widthwise sipes 230 also have the same cross-sectional shape as the widthwise sipes .

[0043] 3, the circumferential sipes 120 and the widthwise sipes 130 have a constant groove width GW1 from the road surface side to the bottom portion. Specifically, the cross-sectional shapes of the circumferential sipes 120 and the widthwise sipes 130 in a cross section along the sipe width direction and the tire radial direction TR are formed to have groove wall surfaces that extend linearly along the tire radial direction TR and are approximately parallel to each other.

[0044] The sipes are narrow grooves that close within the ground contact surface of the land block, and the opening width of the sipes when not in contact with the ground is not particularly limited, but is preferably 0.1 mm to 1.5 mm, and more preferably 0.4 mm to 0.7 mm.

[0045] In this embodiment, the depth D1 of the circumferential sipes 120 and the widthwise sipes 130 is set to about 5.0 mm, and the groove width GW1 is set to about 0.4 mm.

[0046] (4) Block dimensions and bending rigidity As described above, since the block 200 has a shape generally similar to that of the block 100, the dimensions and bending rigidity of the block will be described here using the block 100 shown in FIG. 2 as an example.

[0047] 2, the ratio W2 / W1 of the width W2 of the small block 101 in the tire width direction to the width W1 of the block 100 in the tire width direction is 0.25 or more and 0.50 or less. The ratio L2 / L1 of the length L2 of the small block 101 in the tire circumferential direction TC to the length L1 of the block 100 in the tire circumferential direction TC is 0.1 or more and 0.5 or less.

[0048] As shown in FIG. 2, the width W1, the width W2, the length L1, and the length L2 are based on the tire width direction WD and the tire circumferential direction TC.

[0049] The height of the block 100, that is, the depth of the circumferential grooves 41, 42 and the widthwise grooves 61 defined by the block 100, does not need to be constant, but is about 6 mm to 12 mm.

[0050] The moment of inertia of area based on the height direction of the small block 101 alone is 150 (mm4) or more and 2200 (mm4) or less. The preferable ranges of the width W2 and length L2 of the small block 101 alone are width W2 = 6 to 15 mm, length L2 = 6 to 15 mm.

[0051] The second moment of area is preferably 300 to 1500 (mm4), and more preferably 500 to 1000 (mm4). The block 100 has a triangular shape in a plan view of the tread, and the second moment of area is calculated by (Equation 1).

[0052] (Formula 1) Moment of inertia I=L2*W23 / 36 The relationship between the length L2 and width W2 of each small block 101 is preferably 1.0≦L2 / W2≦1.5. By making L2 / W2 1.0 or more, the road contact is improved and performance on ice is improved. Also, by making L2 / W2 1.5 or less, water generated on the surface of the road surface R can be removed, improving performance on ice.

[0053] (5) Actions and Effects As mentioned above Fruit According to the embodiment, the following advantageous effects can be obtained. Specifically, the block 100 is divided into a plurality of small blocks 101 by the circumferential sipes 120 and the widthwise sipes 130. The circumferential sipes 120 and the widthwise sipes 130 have a constant groove width GW1 from the tread side to the bottom portion (the block 200 also has a similar shape).

[0054] In other words, the circumferential sipes 120 and the widthwise sipes 130 having a constant groove width GW1 extend to the bottom in both the tire circumferential direction TC and the tire width direction WD, thereby ensuring edge pressure at the ends of the blocks 100 in both the tire circumferential direction TC and the tire width direction WD.

[0055] In addition, since the block edge portions of the blocks 100 are divided (divided) by the circumferential sipes 120, the performance of removing water from the tread surface of the blocks 100 can also be ensured.

[0056] As described above, the small block 101 that constitutes the end of the block 100 in the tire circumferential direction TC ensures sufficient edge pressure. This provides a particularly strong grip on the icy and snowy road surface, effectively improving braking and driving performance. Furthermore, the other small blocks 101 provided behind the small block 101 that constitutes the end of the block 100 in the tire circumferential direction TC can firmly contact the road surface.

[0057] In this way, rather than each of the multiple small blocks 101 aiming for "ground contact," "edge effect," and "water removal (drainage)," as described above, each small block 101 is assigned the roles of "ground contact," "edge effect," and "water removal (drainage)."

[0058] In this way, the pneumatic tire 10 can improve performance on ice when using a tread pattern in which blocks with a relatively small contact area are arranged closely together.

[0059] In addition, in this embodiment, the size ratio W2 / W1 between the small block 101 and the block 100 is 0.25 or more and 0.50 or less, and the second moment of area based on the height direction of the block 100 alone is 150 or more and 2200 (mm4) or less.

[0060] Therefore, it is possible to achieve high levels of performance in terms of "ground contact," "edge effect," and "water removal (drainage)." If W2 / W1 is 0.25 or more, the size of the small blocks 101 is not too small, and sufficient ground contact and edge effect can be achieved. If W2 / W1 is 0.50 or less, the size of the small blocks 101 is not too large, and sufficient ground contact can be achieved.

[0061] According to the pneumatic tire 10, by setting W2 / W1 and the bending rigidity of the block 100 alone within the above-mentioned range, it is possible to improve driving performance such as braking / driving performance and steering stability not only on snowy and icy road surfaces but also on dry road surfaces. In other words, the pneumatic tire 10 can exhibit even higher driving performance when using a tread pattern in which blocks with a relatively small contact area are densely arranged.

[0062] In this embodiment, the small block 101 (other blocks and small blocks are generally similar) is a triangular column in a plan view of the tread. Therefore, adjacent small blocks 101 can efficiently support each other via the circumferential sipes 120 and the widthwise sipes 130. In particular, the braking performance on snowy and icy roads during cornering is improved because each small block 101 not only supports the small block 101 adjacent to it in the tire width direction WD during braking, but also supports the small block 101 adjacent to it in the tire circumferential direction TC, thereby increasing the bending rigidity of each block 100 in the tire width direction WD. By increasing the bending rigidity in the tire width direction WD in this way, the ground contact of the tire during braking during cornering can be further improved.

[0063] In this embodiment, the ends of the widthwise sipes 130 communicate with the circumferential groove 41 or the circumferential groove 42 and the widthwise groove 61 formed adjacent to the block 100, and the ends of the circumferential sipes 120 communicate with the widthwise groove 61 formed adjacent to the block 100. This allows the block 100 to exhibit sufficient water removal performance while ensuring the rigidity (block rigidity) of the block 100.

[0064] In this embodiment, the small blocks 101 are formed in triangular columnar shapes in a plan view of the tread. Since snow tends to gather at the positions where the sipes 120, 130 intersect, this configuration can improve friction performance on snow.

[0065] In this embodiment, the width direction grooves 61 and the width direction sipes 130 are inclined with respect to the tire width direction WD, and are parallel to the width direction grooves 61 and the width direction sipes 130. This makes it possible to suppress uneven wear of the blocks 100 and noise (pattern vibration sound) generated when the blocks 100 come into contact with the road surface R.

[0066] (6) Other Variations, etc. End ,fruit Although the embodiment has been described, the present invention is not limited to the description of the embodiment, and it will be apparent to those skilled in the art that various modifications and improvements are possible.

[0067] for example ,figure 4 is, Reference example 2 is a partial planar development view of a tread 20A of a pneumatic tire 10A according to the present invention. This reference example will also be described here.

[0068] 4, the pneumatic tire 10A includes block rows 31A, 32A, and 33A. The block row 31A includes a block 100A, the block row 32A includes a block 200A, and the block row 33A includes a block 300A.

[0069] Since block row 32A and block row 33A have roughly the same shape as block row 31A, the shapes of the blocks that make up the block rows will be described below using block 100A of block row 31A as an example.

[0070] As shown in FIG. 4, the block 100A is composed of a plurality of small blocks 101A partitioned by circumferential sipes 120A and widthwise sipes 130A into a substantially V-shape having corners in the tire circumferential direction in a plan view of the tread.

[0071] This reference example In the tire width direction WD, the edges of each small block 101A extend along the tire circumferential direction TC and are formed to have the same length on both sides in the tire width direction WD. The edges of each small block 101A in the tire circumferential direction are parallel to each other.

[0072] This reference example In the block 100A, the small blocks 101A are arranged adjacent to each other in the tire width direction WD and the tire circumferential direction TC, so that the circumferential sipes 120A extend parallel to the tire circumferential direction TC within the block 100A and open at both ends into the widthwise grooves 61A adjacent to the block 100A. The widthwise sipes 130A extend in a zigzag shape within the block 100A and open at both ends into the circumferential grooves 41A, 42A adjacent to the block 100A.

[0073] In this way, This reference example A block 100A is formed by arranging multiple approximately V-shaped small blocks 101A adjacent to each other in the tire width direction WD and the tire circumferential direction TC, and within the block 100A, the circumferential sipes 120A extend parallel to the tire circumferential direction TC with both ends opening into the adjacent widthwise grooves 61A, and the widthwise sipes 130A extend in a zigzag manner within the block 100A with both ends opening into the adjacent circumferential grooves 41A, 42A, thereby dividing the block 100A into multiple approximately V-shaped small blocks 101A.

[0074] specifically, This reference example In the tire 101A, the small blocks 101A having a substantially V-shape are partitioned so as to be adjacent to each other in the tire width direction WD and the tire circumferential direction TC, so that the first width direction sipe 130Aa and the second width direction sipe 130Ab extending in different directions are connected to each other at their ends to form one zigzag width direction sipe 130A. The first width direction sipe 130Aa and the second width direction sipe 130Ab form corners of the substantially V-shape in the small block 101A in the tire circumferential direction TC.

[0075] As shown in FIG. 4, in the pneumatic tire 10A, the block rows 31A, 32A, 33A are provided only in a center portion CTA partitioned by a pair of circumferential grooves 43A, 44A located on the outermost sides in the tire width direction and arranged on either side of the tire equator line CL.

[0076] This reference exampleIn the pneumatic tire 10A according to the present invention, the widthwise sipes 130A extend in a zigzag pattern within the blocks 100A. As a result, when cornering, each block supports not only the two small blocks 101B adjacent to it in the tire width direction WD, but also the small blocks adjacent to it in the tire circumferential direction TC, increasing the bending rigidity of each block in the tire width direction. This increased bending rigidity improves the tire's ground contact and improves braking performance on snowy and icy roads when cornering.

[0077] moreover, This reference example In the pneumatic tire 10A according to the present invention, each small block 101A in a block 100A partitioned by the circumferential sipes 120A and the widthwise sipes 130A is formed in a substantially V-shape having corners in the tire circumferential direction in a plan view of the tread. This effectively prevents the small blocks from losing ground contact at the acute corners, thereby improving ground contact and improving braking performance on snowy and icy roads.

[0078] Figure 5 shows The above-mentioned embodiment 1 is a partial planar development view of a tread 20B of a pneumatic tire 10B according to a first modified example. FIG.

[0079] 5, the pneumatic tire 10B includes a block row 31. The block row 31 includes a block 100.

[0080] As shown in modification example 1 of Figure 5, a pneumatic tire 10B may have, instead of the block 200 included in the block row 32 of the pneumatic tire 10 of the embodiment, a block 300B partitioned into a plurality of small blocks by a circumferential sipe 320B extending in a zigzag pattern in the block row 32B and a plurality of widthwise sipes 330B extending parallel to each other in the tire width direction WD.

[0081] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure. [Explanation of symbols]

[0082] 10 ,1 0B Pneumatic tires 20 ,2 0B Tread 31,3 2 Block Column 41~43 ,4 1B,43B Circumferential groove 61,61a,61b,62,62a,62 b Width direction groove 100,20 0 block 101,20 1 Small Block 120,22 0 Circumferential sipes 130,130a,130b,230,230a,230 b Width sipes CL Tire Equator Line CT ,C TB Center

Claims

1. A tire having a plurality of block rows defined by a pair of circumferential grooves extending in a tire circumferential direction, The block row includes a plurality of blocks partitioned by a plurality of widthwise grooves extending in the tire width direction, Each of the plurality of blocks included in at least one of the plurality of block rows is partitioned into a plurality of small blocks by a circumferential sipe extending in the tire circumferential direction and a plurality of widthwise sipes extending in the tire width direction, The circumferential sipe extends along the tire circumferential direction, The plurality of widthwise sipes include a first widthwise sipe and a second widthwise sipe extending in different directions from each other, Each block has a triangular shape in a tread plan view, Each of the plurality of small blocks included in each of the blocks also has a triangular shape in a plan view of the tread.

2. 2. The tire according to claim 1, wherein the block row is configured to include a plurality of triangular blocks each including only a plurality of triangular small blocks, and the block row is configured only in a center portion partitioned by a pair of circumferential grooves located outermost in the tire width direction and disposed on either side of the tire equator line.

3. The circumferential sipe has a constant groove width from the tread side to the bottom portion, 3. The tire according to claim 1, wherein each of the plurality of widthwise sipes has a constant groove width from a tread side to a bottom portion.

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