tire

Abstract

To provide a tire which can further improve brake performance on a snow ice road at the time of straight traveling when a tread pattern where blocks having comparatively small contact areas are densely arranged is used.SOLUTION: A tire includes block groups 31, 32 and 33 partitioned by a pair of circumferential grooves 41, 42, 43 and 44 extending in a tire circumferential direction. The block groups include a plurality of blocks 100, 200 an 300 partitioned by a plurality of width direction grooves 61, 62 and 63 extending in a tire width direction. Each block of the block groups 31, 32 and 33 is partitioned into a plurality of small blocks 101, 201 and 301 by circumferential direction sipes 120, 220 an 320 and a plurality of width direction sipes 130, 230 and 330. The circumferential direction sipes in each of the blocks extend in a zigzag shape, and at least the width direction sipes on the outermost side in the tire circumferential direction TC of the plurality of width direction sipes extend in parallel with each other.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 when driving straight ahead.

[0006] Therefore, 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 during straight-line driving when using a tread pattern in which blocks with relatively small contact areas are arranged closely together. [Means for solving the problem]

[0007] The present invention No. one of The tire according to the embodiment includes a block group defined by a pair of circumferential grooves extending in the tire circumferential direction. The block group includes a plurality of blocks defined by a plurality of widthwise grooves extending in the tire width direction. Each of the plurality of blocks is defined 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. Within each of the plurality of blocks, the circumferential sipes extend in a zigzag pattern, and at least the outermost widthwise sipes of the plurality of widthwise sipes in the tire circumferential direction extend parallel to each other. The plurality of small blocks include small blocks that are hexagonal in a plan view of the tread. A tire according to a second aspect of the present invention includes a group of blocks defined by a pair of circumferential grooves extending in the tire circumferential direction. The group of blocks includes a plurality of blocks defined by a plurality of widthwise grooves extending in the tire width direction. Each of the plurality of blocks is defined 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. Within each of the plurality of blocks, the circumferential sipes extend in a zigzag pattern, and at least the outermost widthwise sipes of the plurality of widthwise sipes in the tire circumferential direction extend parallel to each other. The plurality of small blocks include small blocks whose block width at both ends in the tire circumferential direction is wider than the block width at a center portion in a plan view of the tread. Effect of the Invention

[0008] In the above-mentioned tire, each block in the block group is divided into small blocks by zigzag circumferential sipes and multiple widthwise sipes. In this configuration, each small block supports not only the small block adjacent in the tire circumferential direction but also the small block adjacent in the tire width direction during braking, so that the bending rigidity of each block in the tire circumferential direction is increased. This increased bending rigidity improves the tire's ground contact during braking.

[0009] Therefore, according to the above-described 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 straight-line driving 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 first modified example. [Diagram 5] FIG. 5 is a plan view of a portion of a tread of a pneumatic tire 10B according to Modification 2 (Embodiment 1). [Figure 6] FIG. 6 is a plan view of a portion of a tread of a pneumatic tire 10C according to Modification 3 (Embodiment 2). [Figure 7] FIG. 7 is a plan view of a portion of a tread of a pneumatic tire 10D according to Modification 4 (Embodiment 3). [Figure 8] FIG. 8 is a plan view of a portion of a tread of a pneumatic tire 10E according to the fifth 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 basic 1 is a plan view of a portion of a tread of a pneumatic tire 10 according to an embodiment.

[0013] Books basic The pneumatic tire 10 in this embodiment is a so-called winter tire that can run on snowy and icy road surfaces, specifically, on icy and snowy road surfaces, and is also called a studless tire. The pneumatic tire 10 may also be an all-season tire that can run on non-snowy and icy road surfaces (wet and dry road surfaces) and snowy and icy road surfaces. Alternatively, the pneumatic tire 10 may not be a winter tire or an all-season tire, but may be a general summer 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 arranged closely together.

[0016] Specifically, the pneumatic tire 10 includes block rows 31, 32, 33, 34, and 35 extending in the tire circumferential direction TC as shown in Fig. 1. Specifically, the pneumatic tire 10 includes block rows 31, 32, and 33, each of which is a block group and is defined by a pair of adjacent circumferential grooves of circumferential grooves 41, 42, 43, and 44, and block rows 34 and 35, each of which is defined by the circumferential grooves 43 and 44 and a tread end.

[0017] 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.

[0018] In the tread 20, a block row 31 is provided at a position including the tire equator line CL, and a block row 32 and a block row 33 are provided on the outer sides of the block row 31 in the tire width direction.

[0019] Further, a block row 34 is provided on the outer side of the block row 32 in the tire width direction, and a block row 35 is provided on the outer side of the block row 33 in the tire width direction.

[0020] 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 .

[0021] The block row 32 is defined by a circumferential groove 42 and a circumferential groove 43. The block row 33 is defined by a circumferential groove 41 and a circumferential groove 44. Since the block row 34 and the block row 35 are provided in the shoulder region of the tread 20, no circumferential groove is formed on the outer side in the tire width direction.

[0022] (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.

[0023] Specifically, the block row includes a plurality of blocks partitioned by a plurality of widthwise grooves extending in the tire width direction WD. Specifically, block row 31 includes block 100. Block row 32 includes block 200. Block row 33 includes block 300. Block row 34 includes block 400. Block row 35 includes block 500.

[0024] The block 100 is divided by a width direction groove 61. The block 200 is divided by a width direction groove 62. The block 300 is divided by a width direction groove 63. The block 400 is divided by a width direction groove 64. The block 500 is divided by a width direction groove 65.

[0025] The widths of the blocks 100 in the tire circumferential direction TC included in the block row 31 do not all need to be the same. basic In the embodiment, blocks 100 defined by widthwise grooves 61 extending parallel to each other are arranged such that blocks 1001 having a large width in the tire circumferential direction and blocks 1003 having a small width in the tire circumferential direction are alternately arranged.

[0026] The block rows 32 and 33 have substantially the same shape as the block row 31 .

[0027] Specifically, basic In this embodiment, in the block row 32, the blocks 200 defined by the widthwise grooves 62 are arranged such that blocks having a wide circumferential width and blocks having a narrow circumferential width are alternately arranged in the tire circumferential direction. Similarly, in the block row 33, the blocks 300 defined by the widthwise grooves 63 are arranged such that blocks having a wide circumferential width and blocks having a narrow circumferential width are alternately arranged in the tire circumferential direction.

[0028] 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.

[0029] Specifically, the block 100 is divided into nine small blocks 101 by two circumferential sipes 120 and two widthwise sipes 130 .

[0030] Books basic In this embodiment, each end of the widthwise sipes 130 communicates with one of the circumferential grooves. Specifically, the ends of the widthwise sipes 130 communicate with the circumferential grooves 41 and 42.

[0031] The circumferential sipes 120 extend in a zigzag pattern. Both ends of the circumferential sipes 120 communicate with the widthwise grooves 61 adjacent to the blocks 100.

[0032] In addition, basic In this embodiment, the widthwise grooves 61 and the widthwise sipes 130 are inclined with respect to the tire width direction WD. The widthwise grooves 61 and the widthwise sipes 130 are parallel to each other in a plan view of the tread. In other words, the inclination angle of the widthwise grooves 61 with respect to the tire width direction WD is the same as the inclination angle of the widthwise sipes 130 with respect to the tire width direction WD.

[0033] Books basic In this embodiment, the widthwise sipes 130 and the circumferential sipes 120 intersect at the locations where the zigzag circumferential sipes 120 bend.

[0034] The shape of each small block 101 defined by the circumferential sipes 120 and the widthwise sipes 130 in a plan view of the tread may be a polygon surrounded by at least four sides. basicIn this embodiment, the small blocks 101 are rectangular. Specifically, the tire circumferential direction TC of the small blocks 101 is defined by a plurality of widthwise sipes 130 parallel to each other, or widthwise grooves 61 formed parallel to the widthwise sipes 130. The tire width direction WD of the small blocks 101 is defined by circumferential sipes 120 parallel to each other, or circumferential grooves 41, 42. Therefore, the small blocks 101 adjacent to the circumferential grooves 41, 42 have a trapezoidal column shape in a tread plan view, and the small blocks 101 defined by the circumferential sipes 120 at both ends in the tire width direction WD have a parallelogram column shape.

[0035] At least blocks 200 and 300 have a shape generally similar to block 100 .

[0036] Specifically, the block 200 is divided into nine small blocks 201 by two circumferential sipes 220 and two widthwise sipes 230 .

[0037] The ends of the widthwise sipes 230 communicate with the circumferential grooves 42 and 43. The circumferential sipes 120 extend in a zigzag pattern. The circumferential sipes 220 do not directly communicate with the circumferential grooves 42 and 43 adjacent to the block 200, but communicate with the widthwise grooves 62 adjacent to the block 200 at both ends.

[0038] Further, the widthwise grooves 62 and the widthwise sipes 230 are inclined with respect to the tire width direction WD. The widthwise grooves 62 and the widthwise sipes 230 are parallel to each other in a plan view of the tread.

[0039] Also, this basic In this embodiment, the widthwise sipes 230 and the circumferential sipes 220 intersect at a portion where the zigzag circumferential sipes 220 bend.

[0040] The block 300 is divided into nine small blocks 301 by two circumferential sipes 320 and two widthwise sipes 330 .

[0041] The ends of the widthwise sipes 330 communicate with the circumferential grooves 41 and 44. The circumferential sipes 120 extend in a zigzag pattern. The circumferential sipes 320 do not directly communicate with the circumferential grooves 41 and 44 adjacent to the block 200, but communicate with the widthwise grooves 63 adjacent to the block 300 at both ends.

[0042] Moreover, the widthwise grooves 63 and the widthwise sipes 330 are inclined with respect to the tire width direction WD in the opposite direction to the widthwise grooves 61 and the widthwise sipes 130. Furthermore, the widthwise grooves 63 and the widthwise sipes 330 are parallel to each other in a tread plan view.

[0043] Also, this basic In this embodiment, the widthwise sipes 330 and the circumferential sipes 320 intersect at the locations where the zigzag circumferential sipes 320 bend.

[0044] As shown in FIG. 1, in a pneumatic tire 10, a block row 31 including a parallelogram-shaped block 100 having a rectangular columnar small block 101, a block row 32 including a parallelogram-shaped block 200 having a rectangular columnar small block 201, and a block row 33 including a parallelogram-shaped block 300 having a rectangular columnar small block 301 are provided only in a center portion CT partitioned by a pair of circumferential grooves 43, 44 located outermost in the tire width direction and arranged on either side of the tire equator line CL.

[0045] The block 400 is divided into six small blocks 401 by one circumferential sipe 420 and two widthwise sipes 430 .

[0046] An end portion on the inner side in the tire width direction of the widthwise sipe 430 communicates with the circumferential groove 43 , and an end portion of the circumferential sipe 420 communicates with a widthwise groove 64 formed adjacent to the block 400 .

[0047] The circumferential sipes 420 formed in the blocks 400 including the tread ends extend linearly along the tire circumferential direction TC. Furthermore, the widthwise sipes 430 disposed in the blocks 400 are bent at the intersections with the circumferential sipes 420.

[0048] 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.

[0049] The block 500 is also divided into six small blocks 501 by one circumferential sipe 520 and two widthwise sipes 530 .

[0050] An end portion on the inner side in the tire width direction of the widthwise sipe 530 communicates with the circumferential groove 44 , and an end portion of the circumferential sipe 520 communicates with a widthwise groove 65 formed adjacent to the block 500 .

[0051] The circumferential sipes 520 formed in the blocks 500 including the tread ends extend linearly along the tire circumferential direction TC. The widthwise sipes 530 arranged in the blocks 400 are bent at the intersections with the circumferential sipes 520.

[0052] Further, the widthwise grooves 65 and the widthwise sipes 530 are inclined with respect to the tire width direction WD. As shown in Fig. 2, a portion of the widthwise grooves 65 and the widthwise sipes 530 on the circumferential groove 43 side may be more inclined than the other portions.

[0053] As shown in FIG. 1, the block 400 and the block 500 have shapes that are point symmetrical with each other.

[0054] (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.

[0055] At least the circumferential sipes 220, 320 formed in the blocks 200, 300 have a cross-sectional shape similar to that of the circumferential sipes 120 formed in the block 100. The widthwise sipes 230, 330 also have a cross-sectional shape similar to that of the widthwise sipes .

[0056] As shown in Figure 3, basic In this embodiment, the circumferential sipes 120 have a constant groove width GW1 from the road surface side to the bottom portion. The widthwise sipes 130 also 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 so that the sipe wall surfaces extend linearly along the tire radial direction TR and have groove wall surfaces that are approximately parallel to each other.

[0057] A sipe is a narrow groove that closes within the contact surface of the block, and the opening width of the sipe 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.

[0058] Books basic 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.

[0059] (4) Block dimensions and bending rigidity As described above, since the blocks 200 and 300 have roughly the same shape as the block 100, the dimensions and bending rigidity of the blocks will be described here using the block 100 shown in FIG. 2 as an example.

[0060] 2, a dimension W1 of the block 100 along the tire width direction WD is longer than a dimension L1 of the block 100 along the tire circumferential direction TC. In other words, the block 100 is long horizontally.

[0061] 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. W2 / W1 is more preferably 0.30 or more and 0.45 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 preferably 0.1 or more and 0.5 or less, more preferably 0.15 or more and 0.45 or less. L2 / L1 is preferably smaller than W2 / W1.

[0062] The width W1, width W2, length L1, and length L2 are based on the tire width direction WD and tire circumferential direction TC as shown in Fig. 2. The width W2 of the small block 101 may be based on the distance from the end of the small block 101 in the tire width direction to the center of the zigzag shape of the circumferential sipe 120 in the tire width direction, or the distance between the centers of two circumferential sipes 120 adjacent to the small block 101.

[0063] 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.

[0064] The moment of inertia of area of ​​the small block 101 based on the height direction is 150 (mm 4 ) or more, 2200(mm 4 The preferable ranges of the width W2 and length L2 of each small block 101 are W2=9 to 15 mm and L2=6 to 12 mm.

[0065] The second moment of area is 300 to 1500 (mm 4 ) is preferable, and 500 to 1000 (mm 4 ) is more preferable. In the block 100, the small block 101 adjacent to the circumferential grooves 41, 42 has a trapezoidal columnar shape in a tread plan view, and the area second moment is calculated by (Equation 1).

[0066] (Equation 1) Moment of inertia I={(a 2+4ab+b 2 )*h 3} / (36a+36b) As shown in FIG. 2, the length of the upper base of each small block 101 that is trapezoidal in a plan view of the tread is a, the length of the lower base is b, and the height in the direction perpendicular to the widthwise sipe 130 is h.

[0067] The small block 101, both ends of which are partitioned by the circumferential sipes 120, has a parallelogram-like shape in a plan view of the tread, and the second moment of area is calculated by (Equation 2).

[0068] (Formula 2) Moment of inertia I=(W2*L2 3 ) / 12 The relationship between the length L2 and width W2 of each small block 101 is preferably 1.0≦W2 / L2≦1.5. By making W2 / L2 1.0 or more, the road contact is improved and performance on ice is improved. Also, by making W2 / L2 1.5 or less, water generated on the surface of the road surface R can be removed, improving performance on ice.

[0069] (5) Actions and Effects As mentioned above basic According to this embodiment, the following effects can be obtained. Specifically, the block 100 (as well as the other blocks) 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.

[0070] That is, the circumferential sipes 120 and the widthwise sipes 130 having a constant groove width GW1 extend to the bottom in the tire circumferential direction TC and the tire widthwise direction WD, so that the edge pressure of the ends of the blocks 100 in the tire circumferential direction TC and the tire widthwise direction WD can be secured. In addition, the block edge portions of the blocks 100 are divided (compartmented) by the circumferential sipes 120, so that the water removal performance from the tread surface of the blocks 100 can also be secured.

[0071] 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.

[0072] 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)."

[0073] 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.

[0074] Also, this basic In the embodiment, the size ratio W2 / W1 of the small block 101 to 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 (mm 4 ) or less.

[0075] Therefore, it is possible to achieve high levels of performance in terms of "ground contact," "edge effect," and "water removal (drainage)." When 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. Also, when 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.

[0076] 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.

[0077] Books basic In terms of shape, the small block 101 (other blocks and small blocks are generally similar) is a square pillar shape 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 straight driving is improved because, during braking, each small block 101 not only supports the small blocks 101 adjacent to it in the tire circumferential direction TC, but also supports the small blocks 101 adjacent to it in the tire width direction WD, thereby increasing the bending rigidity of each block 100 in the tire circumferential direction TC. By increasing the bending rigidity in the tire circumferential direction TC in this way, the tire's contact with the ground during braking can be further improved.

[0078] Books basic In this embodiment, the ends of the widthwise sipes 130 communicate with the circumferential grooves 41 and 42, and the ends of the circumferential sipes 120 communicate with the widthwise grooves 61 formed adjacent to the block 100. This allows the block 100 to exhibit sufficient water removal performance while ensuring the rigidity of the block 100 (block rigidity).

[0079] Books basic In this embodiment, the width W2 of the block 100 is larger than the length L2 of the block 100, and the block 100 is horizontally long. This can enhance the edge effect (which may be called the edge component) of the end of the block 100 in the tire circumferential direction TC, and can effectively improve the braking performance, which is particularly important on snowy and icy road surfaces.

[0080] Books basicIn this embodiment, the widthwise grooves 61 and the widthwise sipes 130 are inclined with respect to the tire width direction WD, and are parallel to the widthwise grooves 61 and the widthwise 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.

[0081] (6)Other Shape condition That's all, basic The form has been explained, but basic It is not limited to the description of the embodiments, and it will be obvious to those skilled in the art that various modifications and improvements are possible.

[0082] For example, the tread pattern of the above-described pneumatic tire 10 may be modified as follows: Fig. 4 is a partial planar development view of a tread 20A of a pneumatic tire 10A according to a first modified example.

[0083] 4, the pneumatic tire 10A includes block rows 31A, 32A, and 33A, each of which is a block group. 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.

[0084] The following description will be given taking the block 100A as an example. As shown in Fig. 4, the block 100A is divided into nine small blocks 101A by two circumferential sipes 120A and two widthwise sipes 130A.

[0085] basic Compared to the block 100 of the previous embodiment, the first modification is different in that both ends of the block 100A in the tire width direction WD are formed in a zigzag shape parallel to the circumferential sipe 120A in a plan view of the tread. In the first modification, the small blocks 101A adjacent to the circumferential grooves 41A, 42A are also formed in a parallelogram column shape in a plan view of the tread. In the first modification, since the width direction ends of the block 100A are zigzag-shaped, the tread 20A has the circumferential grooves 41A, 42A that extend in a zigzag shape with this surface as a groove wall, and the circumferential grooves extend in a straight shape. basic The shape is different from Tread 20.

[0086] figure 4 1, also in the pneumatic tire 10A, the block rows 31A, 32A, and 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 disposed on either side of the tire equator line CL.

[0087] Figure 5 shows modified example 2. (Embodiment 1) 1 is a partial planar development view of a tread 20B of a tire 10B according to the present invention.

[0088] 5, the pneumatic tire 10B includes block rows 31B, 32B, and 33B, each of which is a block group. The block row 31B includes a block 100B, the block row 32B includes a block 200B, and the block row 33B includes a block 300B.

[0089] The following description will be given taking the block 100B as an example. As shown in Fig. 5, the block 100B is divided into seven small blocks 101B by two circumferential sipes 120B and four widthwise sipes 130B.

[0090] basic As compared with the block 100 of the embodiment, the second modification is different in that the small blocks 101B include small blocks having a hexagonal columnar shape (a hexagon in a plan view of the tread).

[0091] 5, the block 100B is divided by a circumferential sipe 120B that extends in a zigzag shape and communicates with the adjacent widthwise grooves 61B at both ends, and a plurality of widthwise sipes 130B at least one end of which terminates within the block 100B. The end of the widthwise sipe 130B that terminates within the small block 101B communicates with the circumferential sipe 120B at the position where the circumferential sipe 120B bends.

[0092] In addition, in modified example 2, both ends of the widthwise sipe 130B are connected to the closest bending positions in the tire width direction of the two circumferential sipes 120B, or to the closest bending positions in the tire width direction from the circumferential grooves 41B, 42B and the circumferential grooves 41B, 42B of the circumferential sipe 120B, so that each small block 101B is hexagonal prism-shaped.

[0093] basic In comparison with the block 100 of the embodiment, in the modified example 2, the small block 101B located at the end in the tire width direction WD is hexagonal prism-shaped, and therefore, in the tread 20B, the circumferential grooves 41B, 42B extending in a zigzag shape are provided. basic The shape is different from Tread 20.

[0094] As shown in FIG. 5, in a pneumatic tire 10B, block rows 31B, 32B, and 33B are provided only in a center portion CTB partitioned by a pair of circumferential grooves 43B, 44B located on the outermost sides in the tire width direction and arranged on either side of the tire equator line CL.

[0095] In the pneumatic tire 10B of modified example 2, each block supports two small blocks 101B adjacent to each other in the tire width direction WD when cornering, thereby increasing not only the bending rigidity of each block 100B in the tire circumferential direction TC but also the bending rigidity in the tire width direction WD.

[0096] Figure 6 shows modification example 3. (Embodiment 2) 2 is a partial planar development view of a tread 20C of a tire 10C according to the embodiment of the present invention.

[0097] 6, a pneumatic tire 10C includes block rows 31C, 32C, and 33C, each of which is a block group. The block row 31C includes a block 100C, the block row 32C includes a block 200C, and the block row 33C includes a block 300C.

[0098] The following description will be given taking the block 100C as an example. As shown in Fig. 6, the block 100C is divided into eight small blocks 101C by two circumferential sipes 120C and five widthwise sipes 130C.

[0099] basic In comparison with the block 100 of the previous embodiment, the third modification is different in that the small blocks 101C include small blocks having a shape in which the block width at both ends in the tire circumferential direction TC is wider than the block width at the center in a plan view of the tread.

[0100] Specifically, each block 100C is formed in a parallelogram shape in a plan view of the tread as shown in Fig. 6. The block 100C is partitioned by a circumferential sipe 120C extending in a zigzag shape and communicating with adjacent widthwise grooves 61C at both ends, and a plurality of widthwise sipes 130C at least one end of which terminates within the block 100C. The end of the widthwise sipe 130C that terminates within the small block 101C communicates with the circumferential sipe 120C at the position where the circumferential sipe 120C is bent.

[0101] In modification example 3, both ends of the widthwise sipe 130C are connected to the bending positions of the two circumferential sipes 120C that are furthest apart in the tire width direction, or to the circumferential grooves 41C, 42C and the bending positions of the circumferential sipe 120C that are furthest apart in the tire width direction from the circumferential grooves 41C, 42C.

[0102] Therefore, while the blocks 100B of modified example 2 include small blocks 101B having a hexagonal columnar shape, the blocks 100C of the block row 31C formed in the tread 20C of modified example 3 include small blocks whose block width at both ends in the tire circumferential direction TC is wider than the block width at the center when viewed in a plan view of the tread.

[0103] As shown in FIG. 6, in the pneumatic tire 10C, the block rows 31C, 32C, and 33C are provided only in a center portion CTC defined by a pair of circumferential grooves 43C, 44C located on the outermost sides in the tire width direction and arranged on either side of the tire equator line CL.

[0104] The pneumatic tire 10C according to the third modified example has a large moment of inertia with respect to the height direction of each small block 101C, which can suppress collapse of the small blocks 101C and improve friction on ice.

[0105] Figure 7 shows modification example 4. (Embodiment 3) 1 is a partial planar development view of a tread 20D of a tire 10D according to the present invention.

[0106] 7, a pneumatic tire 10D includes a block group 31D in the entire center portion CT partitioned by a pair of circumferential grooves 41D, 42D arranged on either side of a tire equator line CL. The block group 31D includes a plurality of blocks 100D partitioned by a plurality of widthwise grooves 61D inclined with respect to the tire widthwise direction WD and communicating with the circumferential groove 41D but not communicating with the circumferential groove 42D, and a plurality of widthwise grooves 62D inclined in the opposite direction to the widthwise groove 61D with respect to the tire widthwise direction WD and communicating with the circumferential groove 42D but not communicating with the circumferential groove 41D.

[0107] As shown in FIG. 7, a block 100D that is not adjacent to the circumferential grooves 41D, 42D is divided into seven small blocks 101B by four circumferential sipes 120D and four widthwise sipes 130B.

[0108] The block 100D adjacent to the circumferential grooves 41D, 42D is divided into twelve small blocks 101B by four circumferential sipes 120D and seven widthwise sipes 130B.

[0109] Specifically, as shown in Fig. 7, in either case where the block 100D is not adjacent to the circumferential grooves 41D, 42D or adjacent to the circumferential grooves 41D, 42D, the block 100D is partitioned by a circumferential sipe 120D that extends in a zigzag shape and whose both ends communicate with the adjacent widthwise groove 61D, and a plurality of widthwise sipes 130D whose both ends terminate within the block 100D. And, both ends of the widthwise sipe 130D that terminate within the small block 101D communicate with the circumferential sipe 120D at the bending positions of the circumferential sipe 120D, respectively.

[0110] In the fourth modification, both ends of the widthwise sipe 130D communicate with the bending positions of the two circumferential sipes 120B that are closest in the tire width direction, so that each small block 101D has a hexagonal column shape.

[0111] basic When comparing the tread 20 of the embodiment with the tread 20D of the modification example 4, basic In the tread 20 of the above embodiment, a plurality of block groups (block rows 31, 32, 33) were arranged in the center portion CT, but the tread 20D of the fourth modification is different in that a single block group 31D is arranged in the entire center portion CT.

[0112] Furthermore, the fact that the block group 31D is divided into a plurality of blocks 100D by a plurality of widthwise grooves 61D and 62D that intersect with each other is also the same as the fact that the block row 31 is divided into a plurality of blocks 100 by the widthwise grooves 61 that are parallel to each other. basic The shape of the blocks 31, 32, and 33 is different.

[0113] In the pneumatic tire 10D of modified example 4, each block supports two small blocks 101D adjacent to it in the tire width direction WD when cornering, thereby increasing not only the bending rigidity of each block 100D in the tire circumferential direction TC but also the bending rigidity in the tire width direction WD.

[0114] As shown in FIG. 7, in a pneumatic tire 10D, a block group 31D is provided only in a center portion CTD defined by a pair of circumferential grooves 41D, 42D located on the outermost sides in the tire width direction and disposed on either side of the tire equator line CL.

[0115] Furthermore, in the pneumatic tire 10D according to the fourth modified example, the block group 31D arranged in the center portion CT has a plurality of widthwise grooves 61D, 62D that intersect with each other, so that high drainage performance during straight running can be ensured.

[0116] FIG. 8 is a partial planar development view of a tread 20E of a pneumatic tire 10E according to the fifth modified example.

[0117] 8, a pneumatic tire 10E includes block rows 31E and 32E, each of which is a block group. The block row 31E includes a block 100E, and the block row 32E includes a block 200E.

[0118] As shown in the fifth modification of FIG. 8, a pneumatic tire 10E has: basic Instead of the block 300 included in the block row 33 of the pneumatic tire 10 having the above-mentioned configuration, the block row 33E may be provided with a block 300E partitioned into a plurality of small blocks 301E by a circumferential sipe 320E extending parallel to the tire circumferential direction TC and a plurality of widthwise sipes 330E including a first widthwise sipe and a second widthwise sipe extending in different directions from each other.

[0119] 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]

[0120] 10, 10A, 10B, 10C, 10D, 10E Pneumatic tires 20,20A,20B,20C,20D,20E Tread 31~35, 31A~33A, 31B~33B, 31C~33C, 33E Block row (block group) 31D Block Group 41~44,41A~44A,41B~44B,41C~44C,41D,42D,41E,44E Circumferential groove 61~65,61A~63A,61B~63B,61C~63C,61D,62D,63E Width groove 100, 200, 300, 100A, 200A, 300A, 100B, 200B, 300B, 100C, 200C, 300C, 100D, 300E Block 101,201,301,101A,201A,301A,101B,201B,301B,101C,201C,301C,101D,301E Small block 120,220,320,120A,220A,320A,120B,220B,320B,120C,220C,320C,120D,320E Circumferential sipes 130,230,330,130A,230A,330A,130B,230B,330B,130C,230C,330C,130D,330E Width direction sipe CL Tire Equator Line CT, CTA, CTB, CTC, CTD, CTE Center Division

Claims

1. A tire having a group of blocks defined by a pair of circumferential grooves extending in a tire circumferential direction, The block group includes a plurality of blocks partitioned by a plurality of widthwise grooves extending in the tire width direction, Each of the plurality of 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, In each of the plurality of blocks, The circumferential sipe extends in a zigzag pattern, At least the outermost widthwise sipes in the tire circumferential direction of the plurality of widthwise sipes extend parallel to each other, The tire, wherein the plurality of small blocks include small blocks that are hexagonal in a plan view of the tread.

2. The tire according to claim 1 , wherein the group of blocks is provided only in a center portion defined by a pair of circumferential grooves positioned outermost in a tire width direction and disposed on either side of a 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.

4. A tire having a group of blocks defined by a pair of circumferential grooves extending in the tire circumferential direction, The block group includes a plurality of blocks partitioned by a plurality of widthwise grooves extending in the tire width direction, Each of the plurality of 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, In each of the plurality of blocks, The circumferential sipe extends in a zigzag pattern, At least the outermost widthwise sipes in the tire circumferential direction of the plurality of widthwise sipes extend parallel to each other, the plurality of small blocks include small blocks whose block widths at both ends in the tire circumferential direction are wider than the block width at a central portion in a tread plan view.

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