tire

Abstract

To provide a tire improved in on-ice gripping performance.SOLUTION: In a tire 10, a plurality of first sipe units 60A composed of a pair of first sipes, and a plurality of second sipe units 60B composed of a pair of second sipe units, are disposed on at least one land part. All of the first sipes and the second sipes have both ends terminating in the land part. The pair of first sipes has a long side and a short side, which are arranged oppositely to each other in a tire circumferential direction and extend incliningly with respect to a tire width direction so as to face one side in the tire circumferential direction. The pair of second sipes has a long side and a short side that are disposed oppositely to each other in the tire circumferential direction and extend in the tire width direction. The first sipe units 60A and the second sipe units 60B are offset-disposed in the tire width direction.SELECTED DRAWING: Figure 1

Description

【Technical Field】 【0001】 The present invention relates to a tire. 【Background Art】 【0002】 Conventionally, there has been known a tire in which by arranging sipes at high density while suppressing a decrease in rigidity, ice grip performance is improved (for example, Patent Document 1). 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2005-186827 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 However, in the above Patent Document 1, the compatibility between suppressing a decrease in rigidity and arranging sipes at high density is not sufficient, and there is still room for improvement in ice grip performance. 【0005】 Therefore, an object of the present invention is to provide a tire with improved ice grip performance. 【Means for Solving the Problems】 【0006】 The gist of the present invention is as follows. A tire having at least one land portion on a tread surface of the tire, wherein at least one of the land portions is provided with a first sipes unit composed of a pair of first sipes and a second sipes unit composed of a pair of second sipes, both ends of all of the first sipes and the second sipes terminate within the land portion, In the first sipe unit, one first sipe and the other first sipe constituting the pair of first sipes are arranged facing each other in the tire circumferential direction, and each has a long side that extends inclined with respect to the tire width direction so as it moves toward one side in the tire width direction, The first sipe has a short side that extends from either end of the long side in the tire width direction toward the other first sipe, The other first sipe has a short side that extends from the other end of the long side in the tire width direction toward the first first sipe side, In the second sipe unit, one second sipe and the other second sipe constituting the pair of second sipes are arranged facing each other in the circumferential direction of the tire, and each has a long side extending in the width direction of the tire. The first second sipe has a short side that extends from either end of the long side in the tire width direction toward the other second sipe, The other second sipe has a short side that extends from the other end of the long side in the tire width direction toward the first second sipe, A tire characterized in that the first sipe unit and the second sipe unit are offset from each other in the tire width direction. According to the tire of the present invention, ice grip performance can be improved. 【0007】 In the tire of the present invention, Preferably, the first sipe unit and the second sipe unit are arranged in multiple adjacent rows in the circumferential direction of the tire, forming a first sipe unit row and a second sipe unit row, respectively, and the first sipe unit row and the second sipe unit row are offset from each other in the tire width direction. This allows for a more substantial increase in the rigidity of the land portion. 【0008】 In the tire of the present invention, In the row of the first sipe units, in the plurality of first sipe units, the short sides of one of the plurality of first sipes extend along the same straight line along the circumferential direction of the tire, and the short sides of the other of the plurality of first sipes extend along the same straight line along the circumferential direction of the tire. In the row of the second sipe units, it is preferable that the short sides of one of the plurality of second sipes in the plurality of second sipes extend along the same straight line along the tire circumferential direction, and the short sides of the other plurality of second sipes extend along the same straight line along the tire circumferential direction. This makes it easier to arrange multiple sipe units uniformly and at high density on land without creating unnecessary voids. 【0009】 In the tire of the present invention, In the first row of sipe units and the second row of sipe units that are adjacent in the tire width direction, Within the row of the first sipe units, of the plurality of first sipe units, the short side of one first sipe or the short side of the other first sipe, which is positioned on the side of the row of the second sipe units, Preferably, among the short sides of one of the second sipes or the other second sipes in the row of the second sipes, the short side located on the side of the row of the first sipes extends along the same straight line along the circumferential direction of the tire. As a result, braking and driving forces from the edge components can be fully exerted across the entire width of the tire width region where the first and second sipe unit rows are arranged, and the ground pressure distribution of the block's land portion can be made uniform. 【0010】 In the tire of the present invention, In the first sipe unit, the one first sipe and the other first sipe each have their short sides extending along the circumferential direction of the tire. In the second sipe unit, it is preferable that the short side of each of the two second sipes extends along the circumferential direction of the tire. As a result, This design allows for a more efficient arrangement of sipes that can exert braking and driving forces in response to circumferential inputs to the tire, and also more effectively suppresses the reduction in rigidity of the land area around the short side. 【0011】 In the tire of the present invention, In the first sipe unit, the long sides and short sides of the one first sipe and the other first sipe extend parallel to each other, and the one first sipe and the other second sipe are offset in the tire width direction. In the second sipe unit, it is preferable that the long sides and short sides of one second sipe and the other second sipe extend parallel to each other, and that the one second sipe and the other second sipe are offset from each other in the tire width direction. This allows the braking and driving forces from the edge components to be fully utilized, and also helps to equalize the ground pressure distribution on the land area. 【0012】 In the tire of the present invention, In the first sipe unit, the angle between the long side and the short side of each of the first sipes is 90° or greater. In the second sipe unit, it is preferable that the angle between the long side and the short side of one second sipe and the other second sipe, where the two sipes face each other, is 90° or more. This improves tire productivity, prevents large differences in contact pressure, and allows for more effective braking and driving force in the circumferential direction of the tire. 【0013】 In the tire of the present invention, In the first sipe unit, the one first sipe and the other first sipe are congruent with each other, In the second sipe unit, it is preferable that the one second sipe and the other second sipe are congruent with each other. Thereby, in the land portion, it is easy to arrange the sipe units uniformly and at a high density. 【0014】 In the tire of the present invention, In the first sipe unit, the ratio of the length along the extending direction of the long side to the length along the extending direction of the short side of each of the one first sipe and the other first sipe is 1 to 15, In the second sipe unit, it is preferable that the ratio of the length along the extending direction of the long side to the length along the extending direction of the short side of each of the one second sipe and the other second sipe is 1 to 15. Thereby, it is possible to suppress an excessive decrease in sipe density or an excessive decrease in land rigidity, and it is possible to improve the durability of the blade for forming the sipe during tire manufacturing. 【0015】 In the tire of the present invention, The ratio of the tire circumferential direction length along the tire circumferential direction to the tire width direction length along the tire width direction of the first sipe unit is 0.1 to 2.6, It is preferable that the ratio of the tire circumferential direction length along the tire circumferential direction to the tire width direction length along the tire width direction of the second sipe unit is 0.1 to 2.6. Thereby, block rigidity can be more sufficiently ensured, and a more sufficient effect on driving and braking forces can be obtained. 【Advantages of the Invention】 【0016】 According to the present invention, it is possible to provide a tire with improved ice grip performance. 【Brief Description of the Drawings】 【0017】 [Figure 1] This figure schematically shows an unfolded view of the tread surface of a tire according to one embodiment of the present invention. [Figure 2A] This figure illustrates the first sipe unit in Figure 1. [Figure 2B] This figure illustrates the second sipe unit in Figure 1. [Figure 3] This is a diagram illustrating the arrangement of the first and second sipe units, showing an enlarged portion of Figure 1. [Figure 4] This diagram illustrates alternative arrangements of the first and second sipe units. [Figure 5] This figure shows a magnified view of one of the block land areas in Figure 1. [Figure 6] Figure 6(a) shows a comparative example of the block land section, Figure 6(b) shows a comparative example of the block land section, Figure 6(c) shows a comparative example of the block land section, Figure 6(d) shows an example of the block land section, Figure 6(e) shows an example of the block land section, and Figure 6(f) shows an example of the block land section. [Figure 7] Figure 6 shows a graph illustrating the block rigidity and actual contact area in the comparative example and the example shown. [Modes for carrying out the invention] 【0018】 Hereinafter, embodiments of the tire according to the present invention will be described with reference to the drawings. Common components in each figure are denoted by the same reference numerals. 【0019】 Figure 1 is a schematic plan view showing the tread surface of a tire according to one embodiment of the present invention in an unfolded view. 【0020】 In this specification, "tread surface (1)" means the outer surface of the tire that comes into contact with the road surface when the tire, which has been mounted on a rim and filled with a predetermined internal pressure, is rolled under a maximum load. In this specification, "tread edge (TE)" means the edge of the tread surface (1) in the tire width direction. Here, "rim" refers to the standard rim for applicable sizes (Measuring Rim in ETRTO's STANDARDS MANUAL, Design Rim in TRA's YEAR BOOK) which is an industrial standard valid in the region where the tire is produced and used, and is listed or will be listed in the future in publications such as the JATMA YEAR BOOK of JATMA (Japan Automobile Tire Manufacturers Association) in Japan, the STANDARDS MANUAL of ETRTO (The European Tyre and Rim Technical Organization) in Europe, and the YEAR BOOK of TRA (The Tire and Rim Association, Inc.) in the United States. (That is, the above "rim" includes not only current sizes but also sizes that may be included in the above industrial standards in the future. An example of "sizes that will be listed in the future" is the size listed as "FUTURE DEVELOPMENTS" in the 2013 edition of ETRTO's STANDARDS MANUAL.) However, in the case of sizes not listed in the above industrial standards, it refers to a rim with a width corresponding to the tire bead width. Furthermore, "specified internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity of a single wheel in the applicable size and ply rating as described in the JATMA YEAR BOOK, etc., and in the case of sizes not listed in the above industrial standards, it refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle on which the tire is mounted. "Maximum load capacity" refers to the load corresponding to the maximum load capacity mentioned above. Note that the air referred to here can be replaced with an inert gas such as nitrogen gas or other alternatives. 【0021】 In this specification, unless otherwise specified, the dimensions of each element such as grooves, sipes, and block surfaces shall be measured in the "standard condition" described below. The "standard condition" refers to the state in which the tire is mounted on the rim, filled to the specified internal pressure, and unloaded. Here, the dimensions of each element such as grooves, sipes, and block surfaces on the tread surface shall be measured in a flat view of the tread surface. Here, in this specification, "flat view of the tread surface" refers to a plan view of the tread surface when the tread surface is laid out on a plane. 【0022】 In this specification, "groove width" means measured in a cross section perpendicular to the direction of extension of the grooves on the tread surface, in the standard condition described above, and in a direction parallel to the tread surface. The groove width may be constant or vary in the direction perpendicular to the tread surface. However, unless otherwise specified in this specification, "groove width" refers to the groove width on the tread surface. Furthermore, in this specification, "groove depth" means measured in a direction perpendicular to the tread surface, in the standard condition described above. 【0023】 In this specification, "sipe" means a sipe with a width of 1 mm or less over an area of ​​50% or more of the sipe depth in the above-mentioned standard condition. Preferably, the sipe width is 0.6 mm or less. Here, "sipe depth" is measured in the direction perpendicular to the tread surface in the above-mentioned standard condition, and "sipe width" is measured in the direction parallel to the tread surface in a cross section perpendicular to the direction in which the sipe extends on the tread surface in the above-mentioned standard condition. The sipe width may be constant or vary in the direction perpendicular to the tread surface. 【0024】 Furthermore, in this specification, the "length along the direction of extension of the short side" and the "length along the direction of extension of the long side" of a sipe refer to the length of the center line formed by connecting the center points in the width direction of the sipe, and unless otherwise specified, the distances of each component of each sipe shall be measured with respect to the above center line in an unfolded view of the tread surface. 【0025】 For convenience, in this specification, one side of the tire circumferentially (the upper side in Figure 1) will be referred to as the "tire circumferential CD1 side," and the other side of the tire circumferentially (the lower side in Figure 1) will be referred to as the "tire circumferential CD2 side." Furthermore, for convenience, in this specification, one side in the tire width direction (right side in Figure 1) will be referred to as the "WD1 side in the tire width direction," and the other side in the tire width direction (left side in Figure 1) will be referred to as the "WD2 side in the tire width direction." Furthermore, in this specification, for convenience, one of the two types of sipes, sipe units, and rows of sipe units is referred to as the first sipe, the first sipe unit, and the first row of sipe units, and the other as the second sipe, the second sipe unit, and the second row of sipe units. However, it is also possible to swap these terms. That is, if one of the sipes, sipe units, and rows of sipe units is tentatively referred to as the first sipe, the first sipe unit, and the first row of sipe units, then the other is simply referred to as the second sipe, the second sipe unit, and the second row of sipe units. 【0026】 A tire 10 according to one embodiment of the present invention has at least one land portion on the tread surface 1. In the example shown in Figure 1, the tire 10 of this embodiment has a plurality of (four in the illustrated example) circumferential main grooves 2 (2a, 2b, 2c, and 2d) on the tread surface 1 that extend in the circumferential direction of the tire. Each circumferential main groove 2 may extend substantially in a straight line along the circumferential direction of the tire, as shown in Figure 1, or it may extend in a zigzag or wavy shape in the circumferential direction. 【0027】 The groove width of each circumferential main groove 2 is not particularly limited, but can be, for example, 4 to 15 mm. Similarly, the groove depth of each circumferential main groove 2 is not particularly limited, but can be, for example, 6 to 20 mm. 【0028】 Furthermore, in this embodiment, the tire 10 has a tread surface 1 that is divided into multiple (five in the illustrated example) land areas 3 (3a, 3b, 3c, 3d, and 3e) which are demarcated by circumferential main grooves 2a, 2b, 2c, and 2d and the tread edge TE. 【0029】 In this embodiment, each land area 3 is divided into multiple block land areas 5 by multiple transverse grooves 4 extending in a direction intersecting the tire circumferential direction. In the example shown in Figure 1, land area 3a is divided by transverse grooves 41 and has multiple block land areas 51 arranged along the tire circumferential direction. Land area 3b is divided by transverse grooves 42 and has multiple block land areas 52 arranged along the tire circumferential direction. Land area 3c is divided by transverse grooves 43 and has multiple block land areas 53 arranged along the tire circumferential direction. Land area 3d is divided by transverse grooves 44 and has multiple block land areas 54 arranged along the tire circumferential direction. Land area 3e is divided by transverse grooves 45 and has multiple block land areas 55 arranged along the tire circumferential direction. Furthermore, each land area 3 can also be a ribbed land area that is not demarcated by a transverse trench. 【0030】 The width of each lateral groove 4 is not particularly limited, but can be, for example, 2 to 10 mm. Similarly, the depth of each lateral groove 4 is not particularly limited, but can be, for example, 5 to 20 mm. 【0031】 In this embodiment, at least one of the land sections, in the illustrated example, each block land section 5, is equipped with multiple first sipe units 60A, each consisting of a pair of first sipes 6a and 6b (hereinafter also referred to as one first sipe 6a and the other first sipe 6b, or simply first sipes 6a and 6b), and multiple second sipe units 60B, each consisting of a pair of second sipes 6c and 6d (hereinafter also referred to as one second sipe 6c and the other second sipe 6d, or simply second sipes 6c and 6d). In the example shown in Figure 1, each of the block land sections 52, 53, and 54 is equipped with six first sipe units 60A and six second sipe units 60B, respectively, while each of the block land sections 51 and 55 is equipped with three first sipe units 60A and three second sipe units 60B, respectively. 【0032】 The tread surface 1 of the tire 10 in this embodiment is not limited to the example in Figure 1, and may have any tread pattern as long as it has a first sipe unit 60A consisting of a pair of first sipes 6a and 6b and a second sipe unit 60B consisting of a pair of second sipes 6c and 6d. 【0033】 The first sipe unit 60A and the second sipe unit 60B in the tire 10 of this embodiment will be described in detail with reference to Figures 1, 2A, 2B, and 3. Figure 2A is a diagram illustrating the first sipe unit 60A, Figure 2B is a diagram illustrating the second sipe unit 60B, and Figure 3 is an enlarged portion of Figure 1 illustrating the arrangement of the first sipe unit 60A and the second sipe unit B. 【0034】 In the tire 10 of this embodiment, the first sipes 6a and 6b and the second sipes 6c and 6d all terminate at both ends within the block land portion 5. As shown in Figure 1, one first sipe 6a and the other first sipe 6b that constitute the first sipe unit 60A, and one second sipe 6c and the other second sipe 6d that constitute the second sipe unit 60B, all terminate at both ends within the block land portion 5. 【0035】 Furthermore, as shown in Figure 2A, in the tire 10 of this embodiment, one first sipe 6a and the other first sipe 6b of the first sipe unit 60A are arranged facing each other in the tire circumferential direction and each has a long side extending in the tire width direction. In this embodiment, one first sipe 6a and the other first sipe 6b of the first sipe unit 60A each have a long side that extends inclined with respect to the tire width direction so that as you move toward one side in the tire width direction, you move toward one side in the tire circumferential direction. More specifically, as shown in Figure 2A, one first sipe 6a and the other first sipe 6b are spaced apart from each other, and at least a portion of each (in this example, a portion) is arranged facing each other in the tire circumferential direction. Also, as shown in Figure 2A, one first sipe 6a has a long side 61a that extends inclined with respect to the tire width direction so that as you move from the tire width direction WD2 side toward the tire width direction WD1 side toward the tire circumferential direction CD1 side. The other first sipe 6b has a long side 61b that extends inclined with respect to the tire width direction, so as it moves from the tire width direction WD2 side towards the tire width direction WD1 side, it moves toward the tire circumferential direction CD1 side. Thus, both the long sides 61a and 61b extend inclined upward to the right on the paper, as they move toward the tire circumferential direction CD1 side as they move toward the tire width direction WD1 side. Herein, in this specification, "extending in the tire width direction" means extending with at least a component in the tire width direction. That is, "extending in the tire width direction" means that it may extend in a direction along the tire width direction (i.e., at an angle of 0° with respect to the tire width direction and without inclination with respect to the tire width direction), or it may extend at an angle of inclination with respect to the tire width direction (i.e., at an angle of inclination greater than 0° with respect to the tire width direction and inclined with respect to the tire width direction). In the illustrated example, the longer sides 61a and 61b have the same inclination angles θ1 and θ2 with respect to the tire width direction, and are inclined at the same angle, but they may be inclined at different angles. 【0036】 One of the first sipes 6a has a short side 62a that extends from one end e1 of the long side 61a in the tire width direction (in the illustrated example, the WD2 side in the tire width direction) toward the other first sipe 6b. As shown in Figure 2A, the short side 62a extends toward the side where one first sipe 6a and the other first sipe 6b face each other, forming a bending angle θ3 with the long side 61a. The other first sipe 6b has a short side 62b that extends from the end e2 of the long side 61b on the other side (in the illustrated example, the WD1 side in the tire width direction) relative to either of the above sides in the tire width direction, approaching the first first sipe 6a side. As shown in Figure 2A, the short side 62b extends toward the side where the first first sipe 6a and the other first sipe 6b face each other, forming a bending angle θ4 with the long side 61b. Furthermore, in one first sipe 6a and the other first sipe 6b, the short side does not extend from the end of either the long side 61a and 61b in the tire width direction that is not provided with the aforementioned short side 62a and 62b. 【0037】 As shown in Figure 2B, in the tire 10 of this embodiment, one second sipe 6c and the other second sipe 6d of the second sipe unit 60B are arranged facing each other in the tire circumferential direction and each has a long side extending in the tire width direction. In this embodiment, one second sipe 6c and the other second sipe 6d of the second sipe unit 60B each have a long side that extends inclined with respect to the tire width direction so that as you move toward one side in the tire width direction, you move toward the other side in the tire circumferential direction. More specifically, as shown in Figure 2B, one second sipe 6c and the other second sipe 6d are spaced apart from each other, and at least a portion of each (in this example, a portion) is arranged facing each other in the tire circumferential direction. As shown in Figure 2B, one second sipe 6c has a long side 61c that extends inclined with respect to the tire width direction so that as you move from the tire width direction WD2 side toward the tire width direction WD1 side toward the tire circumferential direction toward the tire CD2 side. The other second sipe 6d has a long side 61d that extends inclined with respect to the tire width direction, so as it moves from the tire width direction WD2 side towards the tire width direction WD1 side, it moves toward the tire circumferential direction CD2 side. Thus, both the long sides 61c and 61d extend inclined downward to the right of the paper, as they move toward the tire circumferential direction CD2 side as they move toward the tire width direction WD1 side. In the illustrated example, the long sides 61c and 61d have the same inclination angles θ5 and θ6 with respect to the tire width direction, and are inclined at the same angle. However, they may be inclined at different angles. 【0038】 One of the second sipes 6c has a short side 62c that extends from one end e3 of the long side 61c in the tire width direction (in the illustrated example, the WD1 side in the tire width direction) toward the other second sipe 6d. As shown in Figure 2B, the short side 62c extends toward the side where one second sipe 6c and the other second sipe 6d face each other, forming a bending angle θ7 with the long side 61c. The other second sipe 6d has a short side 62d that extends from the end e4 of the long side 61d on the other side (in the illustrated example, the WD2 side in the tire width direction) relative to either of the above sides in the tire width direction, toward the side of the first second sipe 6c. As shown in Figure 2B, the short side 62d extends toward the side where the first second sipe 6c and the other second sipe 6d face each other, forming a bending angle θ8 with the long side 61d. Furthermore, in both the first second sipe 6c and the second second sipe 6d, the short side does not extend from either end of the long side 61c and 61d in the tire width direction, on the side where the aforementioned short sides 62c and 62d are not provided. 【0039】 In the tire 10 of this embodiment, as shown in Figures 1 and 3, the first sipe unit 60A and the second sipe unit 60B are offset from each other in the tire width direction. When viewed along the tire circumferential direction in an unfolded view of the tread surface 1, the first sipe unit 60A and the second sipe unit 60B are arranged with a phase difference in the tire width direction (i.e., at least a portion of them do not overlap in the tire width direction). 【0040】 The following describes the effects and benefits of the tire configuration of this embodiment. Since both ends of the first sipe 6a, the first sipe 6b, the second sipe 6c, and the second sipe 6d are terminated within the land portion (within the block land portion 5 in this embodiment), it is prevented that open ends of the sipes are formed at the edges of the block land portion 5. As a result, the land portion remains connected around the ends of the first sipe 6a, the first sipe 6b, the second sipe 6c, and the second sipe 6d, which increases the rigidity of the block land portion compared to when the sipes open to the edges of the block land portion. Consequently, deformation of the block land portion 5 is suppressed, lifting at the contact surface is prevented, and the actual contact area with the road surface can be increased, thereby improving ice grip performance. Furthermore, in this embodiment, the first sipes 6a and 6b, and the second sipes 6c and 6d are arranged facing each other in the circumferential direction of the tire, and each has long sides 61a, 61b, 61c, and 61d that extend inclined with respect to the tire width direction so as they move toward one side in the tire width direction, either toward one side in the tire width direction or toward the other side in the tire width direction. As a result, the edge component of the long sides not only allows for sufficient braking and driving force in the circumferential direction (longitudinal direction) of the tire, but also contributes to improving lateral grip performance in the tire width direction. In particular, by setting the inclination angles θ1, θ2, θ5, and θ6 to 45° or less, the tire width direction component of the long side of the sipe becomes equal to or greater than the tire circumferential component, which contributes to improving the braking and driving force, which is of paramount importance for safety. 【0041】 Furthermore, in this embodiment, the first sipes 6a and 6b have short sides 62a and 62b extending from the long sides 61a and 61b to opposite sides, respectively, and the second sipes 6c and 6d have short sides 62c and 62d extending from the long sides 61c and 61d to opposite sides, respectively. As a result, when forming sipes in a mold using a thin metal plate (blade) during the manufacturing process of the tire 10, the short sides of the blade act as support against bending deformation that causes the long sides of the blade to collapse, significantly increasing the bending rigidity of the blade, improving durability, and improving tire productivity. 【0042】 In addition, in this embodiment, the first sipe unit 60A and the second sipe unit 60B are offset from each other in the tire width direction. In this case, the long sides of the first sipe unit 60A and the second sipe unit 60B, which are adjacent in the tire width direction, are inclined in opposite directions (as described above, the long sides 61a and 61b both inclin upward to the right on the paper in each figure, so as they move toward the tire circumferential direction CD1 side as they move toward the tire width direction WD1 side, and the long sides 61c and 61d both inclin downward to the right on the paper in each figure, so as they move toward the tire circumferential direction CD2 side as they move toward the tire width direction WD1 side). As a result, when there is an input to the block's land area in the circumferential direction of the tire, the first sipe unit 60A and the second sipe unit 60B each experience a force that causes them to deform in a collapsing manner (hereinafter also referred to as collapsing deformation) corresponding to their extending direction. However, the first sipe unit 60A and the second sipe unit 60B support each other's collapsing deformation, and together they increase the rigidity of the block's land area, thereby improving ice grip performance. To illustrate with a specific example in Figure 3, for instance, when the block's land portion 5 receives an input in the tire's circumferential direction from the CD1 side to the CD2 side, a force is generated in the land portion adjacent to the first sipe unit 60A that causes it to deform by tilting toward the arrow X1 side, and a force is generated in the land portion adjacent to the second sipe unit 60B that causes it to deform by tilting toward the arrow X2 side. At this time, the land portion near the first sipe unit 60A and the land portion near the second sipe unit 60B each have long sides that are inclined in opposite directions, so they support each other's tilting deformation, thereby increasing the rigidity of the block's land portion 5. In addition, if the long sides of the first sipe unit 60A and the second sipe unit 60B are not in opposite directions but are all inclined in the same direction, a force causing collapse deformation in the same direction will be generated in the land portion near the first sipe unit 60A and the land portion near the second sipe unit 60B. As the entire land portion deforms in the same direction, there is a risk that an unexpected force in the tire width direction will be generated as a reaction force. However, with the configuration of this embodiment, such a reaction force can be canceled out. 【0043】 As described above, according to this embodiment, it is possible to increase the rigidity of the land portion (and consequently the actual contact area) while maintaining the sipe density, that is, to achieve both land portion rigidity and high-density sipe arrangement, thereby improving ice grip performance. 【0044】 In the tire 10 of this embodiment, as shown in Figures 1 and 3, the first sipe unit 60A and the second sipe unit 60B are arranged in multiple adjacent rows in the circumferential direction of the tire, forming the first sipe unit row 7A and the second sipe unit row 7B, respectively, and it is preferable that the first sipe unit row 7A and the second sipe unit row 7B are offset from each other in the tire width direction. In the tire 10 of this embodiment, as shown in Figures 1 and 3, the first sipe unit 60A and the second sipe unit 60B are each arranged in a plurality adjacent to each other in the circumferential direction of the tire, forming the first sipe unit row 7A and the second sipe unit row 7B, respectively. In Figure 1, the rows of first sipe units 60A and second sipe unit rows 7B, each arranged in a plurality adjacent to each other in the circumferential direction of the tire and located on the block land portion 53, are shown as typical examples, referred to as the first sipe unit row 7A and the second sipe unit row 7B, respectively. In the first row of sipe units 7A, adjacent first sipe units 60A are spaced apart from each other, and at least a portion (in this example, all) of each is positioned facing each other in the tire circumferential direction. In the second row of sipe units 7B, adjacent second sipe units 60B are spaced apart from each other, and at least a portion (in this example, all) of each is positioned facing each other in the tire circumferential direction. Furthermore, the first row of sipe units 7A and the second row of sipe units 7B are offset from each other in the tire width direction. As shown in Figures 1 and 3, when viewed along the tire circumferential direction in an unfolded view of the tread surface 1, the first row of sipe units 7A and the second row of sipe units 7B are positioned with a phase difference in the tire width direction (i.e., at least a portion of them do not overlap in the tire width direction). With this configuration, the land portion near the first sipe unit 60A constituting the first sipe unit row 7A and the land portion near the second sipe unit 60B constituting the second sipe unit row 7B each have long sides that are inclined in opposite directions. This allows them to support each other's collapsing deformation, thereby more effectively increasing the rigidity of the block land portion 5. In addition, if the long sides of the first sipe unit 60A constituting the first sipe unit row 7A and the long sides of the second sipe unit 60B constituting the second sipe unit row 7B are all inclined in the same direction, the entire land portion will deform in the same direction, potentially generating an unexpected force in the tire width direction as a reaction force. However, with the configuration of this embodiment, such reaction forces can be more effectively offset. 【0045】 The following describes preferred configurations and modified examples of the tire 10 of this embodiment. 【0046】 In the tire 10 of this embodiment, the depth of each of the first sipes, such as one first sipe 6a, the other first sipe 6b, one second sipe 6c, and the other second sipe 6d, is not particularly limited. However, from the viewpoint of more effectively improving grip performance on ice, it is preferable to set it to 3 mm or more, and for example, it may be 10 mm or less. 【0047】 In the tire 10 of this embodiment, it is preferable that in the first sipe unit 60A, one first sipe 6a and the other first sipe 6b extend parallel to each other along their long sides and short sides. As shown in Figure 2A, the long sides 61a and 61b extend parallel to each other, and the short sides 62a and 62b extend parallel to each other. In addition, in the tire 10 of this embodiment, it is preferable that one first sipe 6a and the other first sipe 6b are offset in the tire width direction. Furthermore, in the tire 10 of this embodiment, it is preferable that in the second sipe unit 60B, the long sides and short sides of one second sipe 6c and the other second sipe 6d extend parallel to each other. As shown in Figure 2B, the long sides 61c and 61d extend parallel to each other, and the short sides 62c and 62d extend parallel to each other. In addition, in the tire 10 of this embodiment, it is preferable that one second sipe 6c and the other second sipe 6d are offset in the tire width direction. In Figure 2A, when viewed along the tire circumferential direction in an unfolded view of the tread surface 1, the first sipe 6a and the first sipe 6b overlap in some areas in the tire width direction, while being positioned with a phase shift in the tire width direction (i.e., some areas do not overlap in the tire width direction). In Figure 2B, when viewed along the tire circumferential direction in an unfolded view of the tread surface 1, the second sipe 6c and the second sipe 6d overlap in some areas in the tire width direction, while being positioned with a phase shift in the tire width direction (i.e., some areas do not overlap in the tire width direction). By arranging the long sides and short sides of the first sipes 6a and 6b parallel to each other, and by arranging the long sides and short sides of the second sipes 6c and 6d parallel to each other, the distances in the tire circumferential direction and tire width direction can be kept constant for each of the first sipe units 60A and 60B, both along their long sides and short sides. Therefore, when arranging multiple first sipe units 60A and second sipe units 60B adjacent to each other in the tire circumferential direction on the block land portion 5, it is easy to arrange the first sipe units 60A and second sipe units 60B uniformly and at a high density without forming unnecessary gaps. In addition, by offsetting one first sipe 6a from the other first sipe 6b, and one second sipe 6c from the other second sipe 6d in the tire width direction, when each of the first sipe unit 60A and the second sipe unit 60B is viewed along the tire circumferential direction in an unfolded view of the tread surface 1, the sipes will be present over a wider area in the tire width direction compared to when one sipe and the other sipe are not offset. As a result, braking force and driving force due to the edge component can be fully exerted over a wider area in the tire width direction, and the ground pressure distribution of the block land portion 5 can be made more uniform. 【0048】 In the tire 10 of this embodiment, the long sides 61a and 61b of the first sipe 6a and the first sipe 6b are preferably inclined at angles θ1 and θ2 with respect to the tire width direction of 0° or more and 45° or less, and more preferably at angles greater than 0° and less than 45°. Furthermore, the long sides 61c and 61d of the second sipe 6c and the second sipe 6d are preferably inclined at angles θ5 and θ6 with respect to the tire width direction of 0° or more and 45° or less, and more preferably at angles greater than 0° and less than 45°. By setting the inclination angles θ1, θ2, θ5, and θ6 to 0° or more and 45° or less, the braking and driving forces in the tire circumferential direction (front-to-back direction) due to the edge component of the longer side are fully realized. By setting the inclination angles θ1, θ2, θ5, and θ6 to more than 0°, the edge effect is also obtained in the tire width direction, and by setting the inclination angles θ1, θ2, θ5, and θ6 to less than 45°, the braking and driving forces in the tire circumferential direction (front-to-back direction) due to the edge component of the longer side are even more fully realized. 【0049】 In the tire 10 of this embodiment, in the first sipe unit 60A, it is preferable that the angle θ3, which is the angle between the long side 61a and the short side 62a of one first sipe 6a and the other first sipe 6b facing each other, and the angle θ4, which is the angle between the long side 61b and the short side 62b facing each other, are 90° or more. In addition, in the second sipe unit 60B, it is preferable that the angle θ7, which is the angle formed by the long side 61c and the short side 62c of one second sipe 6c and the other second sipe 6d facing each other, and the angle θ8, which is the angle formed by the long side 61d and the short side 62d facing each other, are 90° or more. With this configuration, when forming sipes in a mold using a blade during the manufacturing process of the tire 10, the short side of the blade provides more effective support against bending deformation that causes the long side of the blade to collapse, thereby increasing the bending rigidity of the blade, more effectively improving durability, and improving tire productivity. Furthermore, by setting angles θ3, θ4, θ7, and θ8 to 90° or more, it is possible to prevent the formation of acute corners in the land portion near the vertices of the long and short sides, i.e., the formation of localized low-rigidity areas, thereby suppressing deformation around these areas, preventing large differences in contact pressure, and allowing braking and driving forces in the circumferential direction of the tire to be exerted more effectively. Furthermore, it is more preferable that angles θ3, θ4, θ7, and θ8 be 150° or less. By setting angles θ3, θ4, θ7, and θ8 to 150° or less, a moderate bend is formed between the short and long sides compared to when the angles exceed 150°, which improves the durability of the blades that form the sipes during tire manufacturing. 【0050】 Furthermore, in the tire 10 of this embodiment, as shown in Figures 1, 2A, and 2B, it is preferable that in the first sipe unit 60A, one first sipe 6a and the other first sipe 6b have short sides 62a and 62b extending along the tire circumferential direction, and in the second sipe unit 60B, one second sipe 6c and the other second sipe 6d have short sides 62c and 62d extending along the tire circumferential direction. Note that "extending along the tire circumferential direction" includes cases where it is parallel to the tire circumferential direction or inclined at an extremely low angle with respect to the tire circumferential direction (for example, an inclination angle of 5° or less with respect to the tire circumferential direction). With such a configuration, sipes that can exert braking force and driving force in response to input in the tire circumferential direction can be arranged more efficiently, and since the direction of the short side substantially coincides with the input direction of the braking and driving force, the block land portion is not divided with respect to the input direction, and the reduction in rigidity of the land portion around the short side can be suppressed more effectively. Furthermore, with this configuration, by removing the water film on the ice surface, the water accumulated on the long side of the sipe is efficiently guided in the circumferential direction of the tire, which is the direction of slippage during braking, by the short side of the sipe that extends along the tire's circumferential direction and is located at the end of the long side, thereby promoting drainage. Furthermore, when the short sides 62a and 62b extend along the tire circumferential direction, it is preferable that angles θ3 and θ4 be greater than 90° and 135° or less, from the viewpoint of forming an appropriate bend between the short and long sides to more effectively improve the durability of the blade that forms the sipes during tire manufacturing, and to ensure that braking and driving forces in the tire circumferential direction (forward and backward direction) are sufficiently exerted by the edge component of the long side. Similarly, when the short sides 62c and 62d extend along the tire circumferential direction, it is preferable that angles θ7 and θ8 be greater than 90° and 135° or less, from the viewpoint of forming an appropriate bend between the short and long sides to more effectively improve the durability of the blade that forms the sipes during tire manufacturing, and to ensure that braking and driving forces in the tire circumferential direction (forward and backward direction) are sufficiently exerted by the edge component of the long side. As described above, by setting the inclination angle of the long side with respect to the tire width direction to 0 to 45°, the effect on the braking and driving performance, which is the most important for safety, can be maximized. To maintain this angle and align the shorter side roughly in the circumferential direction, the bending angle between the longer and shorter sides needs to be between 90 and 135°. In the tire 10 of this embodiment, for example, the inclination angles θ1 and θ2 of the longer sides 61a and 61b are 30°, and angles θ3 and θ4 are 120°. 【0051】 In the tire 10 of this embodiment, as shown in Figures 1, 2A, and 2B, it is preferable that in the first sipe unit 60A, one first sipe 6a and the other first sipe 6b are congruent, and in the second sipe unit 60B, one second sipe 6c and the other second sipe 6d are congruent. With such a configuration, when arranging multiple first sipe units 60A and second sipe units 60B adjacent to each other in the circumferential direction of the tire in the block land portion 5, it is easy to arrange them uniformly and at a high density. Furthermore, for similar reasons, in the tire 10 of this embodiment, as shown in Figure 1, it is preferable that one first sipe 6a, the other first sipe 6b, one second sipe 6c, and the other second sipe 6b are all congruent to each other. As shown in Figures 1 and 3, all sipes in the first sipe unit row 7A may be congruent, and all sipes in the second sipe unit row 7B may also be congruent, and all sipes in both the first sipe unit row 7A and the second sipe unit row 7B may be congruent. Here, "congruent" refers to congruence including mirror images, meaning that in a view of the tread surface, they completely overlap each other through translation, rotation, and / or symmetry. 【0052】 In the tire 10 of this embodiment, in the first sipe unit 60A, the ratio of the length of the long sides 61a and 61b along the extending direction to the length of the short sides 62a and 62b is preferably 1 to 15 for one first sipe 6a and the other first sipe 6b, respectively, and in the second sipe unit 60B, the ratio of the length of the long sides 61c and 61d along the extending direction to the length of the short sides 62c and 62d is preferably 1 to 15 for one second sipe 6c and the other second sipe 6d, respectively. In Figure 2A, it is preferable that the ratio of the length L2 of the long side 61a along the extending direction to the length L1 of the short side 62a along the extending direction is 1 to 15, and the ratio of the length L4 of the long side 61b along the extending direction to the length L3 of the short side 62b along the extending direction is 1 to 15. In Figure 2B, it is preferable that the ratio of the length L8 of the long side 61c along the extending direction to the length L7 of the short side 62c along the extending direction is 1 to 15, and the ratio of the length L10 of the long side 61d along the extending direction to the length L9 of the short side 62d along the extending direction is 1 to 15. With this configuration, the ratio of the length of the long side to the short side is 1 or more, which suppresses an excessive decrease in sipe density or an excessive decrease in land area rigidity. Furthermore, the ratio of the length of the long side to the short side is 15 or less, which improves the durability of the blades that form the sipes during tire manufacturing. 【0053】 In the tire 10 of this embodiment, the lengths L2 and L4 along the extending direction of the long sides 61a and 61b in the first sipe unit 60A, and the lengths L8 and L10 along the extending direction of the long sides 61c and 61d in the second sipe unit 60B are not particularly limited, but from the viewpoint of maintaining the rigidity of the block land portion 5 while fully demonstrating the ice grip performance of the tire, and from the viewpoint of enabling application to a variety of tires, it is preferable that each of these values ​​be 3 to 15 mm. 【0054】 Furthermore, in the tire 10 of this embodiment, the lengths L1 and L3 along the extending direction of the short sides 62a and 62b in the first sipe unit 60A, and the lengths L7 and L9 along the extending direction of the short sides 62c and 62d in the second sipe unit 60B are not particularly limited, but from the viewpoint of more effectively improving the durability of the blades that form the sipes during tire manufacturing, it is preferable that they be 1 mm or more, and less than the same value as the lengths L2 and L4 along the extending direction of the long sides 61a and 61b, and the lengths L8 and L10 along the extending direction of the long sides 61c and 61d. 【0055】 Furthermore, in the tire 10 of this embodiment, it is preferable that the ratio of the tire circumferential length L6 along the tire circumferential direction to the tire width direction length L5 along the tire width direction of the first sipe unit 60A is 0.1 to 2.6, and the ratio of the tire circumferential length L12 along the tire circumferential direction to the tire width direction length L11 along the tire width direction of the second sipe unit 60B is 0.1 to 2.6. Here, "length in the tire width direction along the tire width direction" refers to the length in the tire width direction along a straight line parallel to the tire width direction. In Figure 2A, this refers to the distance between the end of the first sipe 6a on the WD2 side in the tire width direction at the center line C1 and the end of the first sipe 6b on the WD1 side in the tire width direction at the center line C2. In Figure 2B, this refers to the distance between the end of the second sipe 6c on the WD1 side in the tire width direction at the center line C3 and the end of the second sipe 6d on the WD2 side in the tire width direction at the center line C4. "Tire circumferential length along the tire's circumferential direction" refers to the tire's circumferential length along a straight line parallel to the tire's circumferential direction. In Figure 2A, this refers to the distance between the CD1 side of the tire's circumferential direction at the center line C1 of the first sipe 6a and the CD2 side of the tire's circumferential direction at the center line C2 of the first sipe 6b. In Figure 2B, this refers to the distance between the CD1 side of the tire's circumferential direction at the center line C3 of the second sipe 6c and the CD2 side of the tire's circumferential direction at the center line C4 of the second sipe 6d. A ratio of 0.1 or greater prevents the circumferential distance between sipes from becoming too narrow, thus ensuring sufficient block rigidity. Furthermore, a ratio of 2.6 or less prevents the inclination angles θ1 and θ2 of the long sides 61a and 61b from becoming excessively large, and prevents the tire widthwise lengths of the long sides 61a and 61b from becoming too short, thus achieving a more sufficient effect on braking and driving forces. 【0056】 In the tire 10 of this embodiment, as shown in Figure 3, in the multiple (three in the illustrated example) first sipe units 60A within the first sipe unit row 7A, the short sides 62a of one of the multiple (all in this example) first sipes 6a extend along the same straight line along the tire circumferential direction (on the imaginary line Y1 extending along the tire circumferential direction in Figure 3), and the short sides 62b of the other (all in this example) first sipes 6b extend along the same straight line along the tire circumferential direction (on the imaginary line Y1 extending along the tire circumferential direction in Figure 3). It is preferable that, in multiple (in this example, three) second sipe units 60B within the second sipe unit row 7B, the short sides 62d of multiple (in this example, all) other second sipes 6d extend along the same straight line along the tire circumferential direction (in Figure 3, along the imaginary line Y2 extending along the tire circumferential direction), and the short sides 62c of multiple (in this example, all) one of the second sipes 6c extend along the same straight line along the tire circumferential direction (in Figure 3, along the imaginary line Y3 extending along the tire circumferential direction). With this configuration, the phases in the tire width direction are aligned in both the first sipe units 60A and the second sipe units 60B, which are arranged adjacent to each other in the circumferential direction of the tire. Therefore, it is easy to arrange multiple first sipe units 60A and second sipe units 60B uniformly and at a high density in the block land portion 5 without forming unnecessary voids. 【0057】 Furthermore, in the tire 10 of this embodiment, it is preferable that in each of the first sipe unit row 7A and the second sipe unit row 7B, a plurality of first sipe units 60A and second sipe unit rows 7B are arranged adjacent to each other in the circumferential direction of the tire at a certain interval. The spacing between the first sipe units 60A and the spacing between the second sipe units 60B will be described below, with the configuration of the first sipe unit row 7A and the second sipe unit row 7B being explained using the first sipe unit row 7A as a typical example. In the example shown in Figure 3, all the long sides included in the first sipe unit row 7A extend parallel to each other. Furthermore, the other first sipe 6b of the first sipe unit 60A is positioned with a phase offset of s in the tire width direction and q in the tire circumferential direction relative to the first first sipe 6a. In the first sipe unit row 7A, the first sipe units 60A are arranged repeatedly in the tire circumferential direction at a pitch p. Here, if the distance between adjacent first sipe units 60A in the tire circumferential direction is denoted as the inter-unit distance r, then the inter-unit distance r is given by r = pq. In particular, when the pitch p between adjacent first sipe units 60A in the tire circumferential direction and the circumferential offset q between the first sipe 6a and the first sipe 6b constituting the first sipe unit 60A are q = p / 2, then r = q (inter-unit distance r = tire circumferential offset q), and all sipes within the first sipe unit 60A and between the first sipe units 60A are arranged at equal intervals in the circumferential direction. For this reason, it is preferable to set q in the range of (p / 2) × 0.8 to (p / 2) × 1.2, and more preferably to set q to p / 2, thereby making the sipe density in the tire circumferential direction in the block land portion 5 uniform. Therefore, the contact surface of the block land portion 5 can be made to contact the road surface more uniformly, the distribution of ground pressure applied to the contact surface of the block land portion 5 can be made uniform, and the contact area of ​​the tire 10 can be increased. 【0058】 Furthermore, in the tire 10 of this embodiment, it is preferable that in the first sipe unit row 7A and the second sipe unit row 7B, a plurality of first sipe units 60A and second sipe unit rows 7B are arranged at regular intervals in the circumferential direction of the tire. As shown in Figure 3, the first sipe unit row 7A (more specifically, the first sipe unit 60A within the first sipe unit row 7A) and the second sipe unit row 7B (more specifically, the second sipe unit 60B within the second sipe unit row 7B) are positioned with a phase difference of offset u in the circumferential direction of the tire. When the offset u and the pitch p of adjacent first sipe units 60A in the circumferential direction of the tire (the pitch of adjacent second sipe units 60B in the circumferential direction of the tire is also p) is u = p / 2, the first sipe units 60A and second sipe unit rows 7B are arranged at equal intervals in the circumferential direction of the tire. Therefore, it is preferable to set the offset u in the range of (p / 2) × 0.8 to (p / 2) × 1.2, and more preferably to set u to p / 2, which makes it possible to equalize the sipe density in the circumferential direction of the tire on the block land portion 5. As a result, the contact surface of the block land portion 5 can be made to contact the road surface more uniformly, the distribution of contact pressure applied to the contact surface of the block land portion 5 can be equalized, and the contact area of ​​the tire 10 can be increased. 【0059】 In Figures 3 and 4, the distance between adjacent first sipe unit row 7A and second sipe unit row 7B in the tire width direction is indicated by v. The above-mentioned circumferential offset u and widthwise spacing v of the tire may each be set to any arbitrary value. 【0060】 Here, as described above, when the offset in the tire width direction between a pair of first sipes and a pair of second sipes within each sipe unit is s (s>0), it is preferable that the interval v be -s to s. Note that an interval v of a negative value (for example, -s) means that the first sipe unit row 7A and the second sipe unit row 7B overlap in the tire width direction by the absolute value of v when viewed along the tire circumferential direction. When v is greater than or equal to -s, the sipes placed on the land area do not become too dense, and sufficient land area rigidity can be ensured. When v is a positive value, a continuous area in the circumferential direction of the land area and, consequently, even greater land area rigidity can be ensured. When v is less than or equal to s, sufficient sipe density can be ensured on the land area. In particular, when v=0, adjacent rows of sipe units are arranged continuously in the tire width direction, thus preventing the occurrence of blank areas between rows of sipe units where no sipes exist. Also, when v=0, the shorter sides of adjacent rows of sipe units can be aligned in a straight line along the tire circumference, which synergistically enhances the drainage effect. For this reason, setting v=0 is particularly preferable. 【0061】 Figure 4 is a diagram illustrating a different arrangement of the first sipe unit 60A and the second sipe unit 60B compared to Figure 3. It is preferable that the circumferential end of the short side of one (or the other) sipe within each sipe unit does not protrude further in the circumferential direction of the tire than the circumferential end of the long side of the other (or the other) sipe. More specifically, for example, in Figure 4, the end E1 on the CD1 side of the short side 62d of the second sipe 6d protrudes further toward the CD1 side of the tire than the end E2 on the CD1 side of the long side 61c of the second sipe 6c. However, in the case of an input from the CD1 side toward the CD2 side of the tire, it is preferable that the end E1 does not protrude further toward the CD1 side of the tire than the end E2, from the viewpoint of securing a wider area enclosed by the dotted line in Figure 4 and further improving the rigidity of the ground portion. 【0062】 In the tire 10 of this embodiment, more preferably as shown in Figure 3, in the first row of sipe units 7A and the second row of sipe units 7B, which are adjacent in the tire width direction, the short side on the second row of sipe units 7B, which is offset in the tire width direction from the short side 62a of one of the multiple first sipe units 60A in the first row of sipe units 7A or the short side 62b of the other first sipe 6b, and the short side on the first row of sipe units 7A, which is offset in the tire width direction from the short side 62c of one of the multiple second sipe units 60B in the second row of sipe units 7B or the short side 62d of the other second sipe 6d, extend along the same straight line along the tire circumferential direction. In the example shown in Figure 3, the short side 62b of the first sipe unit 60A on the side of the second sipe unit row 7B and the short side 62d of the second sipe unit 60B on the side of the first sipe unit row 7A extend along the same straight line along the tire circumferential direction (in Figure 3, along the imaginary line Y2 extending along the tire circumferential direction). With this configuration, the distance v in the tire width direction between the first sipe unit row 7A and the second sipe unit row 7B becomes v=0, and when the first sipe unit 60A and the second sipe unit 60B are viewed along the tire circumferential direction in an unfolded view of the tread surface 1, sipes will be present along the entire width in the tire width direction, from the end of the first sipe unit row 7A on the WD2 side in the tire width direction to the end of the second sipe unit row 7B on the WD1 side in the tire width direction. As a result, the first sipe unit 60A and the second sipe unit 60B work together as a single unit, and the braking and driving forces from the edge component can be fully exerted across the entire width of the tire width region where the first sipe unit row 7A and the second sipe unit row 7B are arranged, and the ground pressure distribution of the block land portion 5 can be made more uniform. In addition, a more sufficient area of ​​continuous land portion around the short side can be secured. 【0063】 In the tire 10 of this embodiment, the number and density of the first sipe units 60A and second sipe units 60B arranged on each block land portion 5 are not particularly limited. As described above, in the example shown in Figure 1, six first sipe units 60A and six second sipe units 60B are arranged on each block land portion 52, 53, and 54, and three first sipe units 60A and three second sipe units 60B are arranged on each block land portion 51 and 55. 【0064】 The total number of first sipes 6a and 6b, which constitute the first sipe unit 60A, and second sipes 6c and 6d, which constitute the second sipe unit 60B, arranged in the block land section 5, may be determined, for example, based on the sipe density SD described below. 【0065】 The method for calculating sipe density SD is described below. Figure 5 is an enlarged view of one of the block land sections 53 in Figure 1. As shown in Figure 5, when block land section 53 in Figure 1 is a typical example of block land section 5, let n be the total number of sipes 6a, 6b, 6c, and 6d in block land section 5, let d be the tire width direction length of each of the sipes 6a, 6b, 6c, and 6d (in Figure 5, the tire width direction length of sipe 6a is shown as d), and let h be the sipe depth of sipes 6a, 6b, 6c, and 6d. Then d × h is, for example, 150 (mm) 2 ) can be less than or equal to. Also, if the maximum length of the block land portion 5 in the tire width direction is BW (mm), the equivalent number of sipes N is expressed as d × n / BW. Here, the equivalent number of sipes N is the number obtained when the first sipes 6a, first sipes 6b, second sipes 6c and second sipes 6d of this embodiment are converted to transverse sipes (equivalent sipes) that are provided so as to completely cross the block land portion 5. Furthermore, the outer contour area of ​​the block land portion 5 (mm 2If the equivalent circumferential length of the land portion of the tire obtained by dividing ) by the aforementioned BW (mm) is denoted as BL (mm), then the average sipe spacing is expressed as BL / (N+1). Here, the average sipe spacing is the spacing of the equivalent sipes in the circumferential direction of the tire on the block land portion 5 when the first sipe 6a, first sipe 6b, second sipe 6c, and second sipe 6d of this embodiment are converted to equivalent sipes. The sipe density SD is expressed as the reciprocal of the average sipe spacing by the following formula. SD=(N+1) / BL=((d×n / BW)+1) / BL···(Formula 1) The total number of sipes n within the block, the length d of each sipe in the tire width direction, the maximum length BW of the block in the tire width direction, and the outer contour area of ​​the block are all values ​​measured from a flat view of the tread surface. The "outer contour area" of the block refers to the area enclosed by the outer contour of the block when viewed from a flat view of the tread surface. Therefore, even if non-contact areas such as sipes, small holes, or narrow grooves are located within the block, this refers to the area that does not exclude the area of ​​such sipes, small holes, or narrow grooves. 【0066】 For example, the block's land portion 5 may have multiple first sipes 6a, first sipes 6b, second sipes 6c, and second sipes 6d arranged such that the sipe density SD is 0.15 or higher. This makes it possible to increase the sipe density while suppressing a decrease in the rigidity of the land portion, thereby more effectively improving the tire's grip performance on ice. [Examples] 【0067】 The following describes embodiments of the present invention, but the present invention is not limited thereto. 【0068】 For the test tires (Comparative Examples 1-3 and Examples 1-3) 1-6, the effect of suppressing lift at the contact surface was calculated using the finite element method (FEM). Each test tire has block sections on the tread surface as shown in Table 1 and Figures 6(a)-(f). The results for the comparative examples and examples shown in Table 1 and Figure 6 are shown in Figure 7 as a graph. As shown in Figure 7, the horizontal axis of the graph is block stiffness (N / mm), and the vertical axis of the graph is the actual contact area (mm²) under shear. 2 ) The FEM prediction calculations were performed under conditions where a vertical load was applied, calculated by multiplying the outer contour area of ​​the block's land portion by the standard contact pressure of a passenger car tire (230 kPa), to evaluate the block stiffness and contact area. For block stiffness, the shear input value in the same direction was determined when the lateral displacement in the tire circumferential direction was 1 mm. For actual contact area, it was determined by the remaining contact area when partial lift occurred, with the shear input in the tire circumferential direction being 0.3 times the vertical load mentioned above. As shown in Figure 7, even with the same number of sipes and thus sipe density (between Comparative Example 1 and Example 1, Comparative Example 2 and Example 2, and Comparative Example 3 and Example 3), the Examples have greater block rigidity and actual contact area, and consequently, a greater effect in suppressing lift at the contact surface of the block's land portion, thereby improving ice grip performance. 【0069】 [Table 1] [Industrial applicability] 【0070】 The pneumatic tire according to the present invention can be used for any type of pneumatic tire. However, it can be used preferably for passenger car tires or truck / bus tires, and more preferably for winter passenger car tires or winter truck / bus tires. [Explanation of Symbols] 【0071】 1: Tread surface, 2, 2a, 2b, 2c, 2d: Circumferential main grooves, 3, 3a, 3b, 3c, 3d, 3e: Land area, 4, 41, 42, 43, 44, 45: Transverse grooves, 5, 51, 52, 53, 54, 55: Block land area, 6a: First sipe (one of the first sipes), 6b: First sipe (the other of the first sipes), 6c: Second sipe (one of the second sipes), 6d: Second sipe (the other of the second sipes), 7A: First sipe unit row, 7B: Second sipe unit row, 10: Tire, 60A: First sipe unit, 60B: Second sipe unit, 61a, 61b, 61c, 61d: Long side, 62a, 62b, 62c, 62d: Short side e1, e2, e3, e4: ends, E1, E2: ends, C1, C2: centerlines, WD1, WD2: tire width direction, CD1, CD2: tire circumferential direction, TE: tread end, Y1, Y2, Y3: imaginary lines, d: tire width direction length of sipe, s: tire width direction offset, p: pitch of sipe unit in the tire circumferential direction, q: tire circumferential offset, u: tire circumferential offset of adjacent sipe unit rows in the tire width direction, v: tire width direction spacing between adjacent sipe unit rows in the tire width direction, r: distance between adjacent sipe units in the tire circumferential direction

Claims

[Claim 1] A tire having at least one land area on the tread surface of the tire, At least one of the land portions is provided with a first sipe unit consisting of a pair of first sipes and a second sipe unit consisting of a pair of second sipes. Both the first and second sipes terminate within the land area. In the first sipe unit, one first sipe and the other first sipe constituting the pair of first sipes are arranged facing each other in the tire circumferential direction, and each has a long side that extends inclined with respect to the tire width direction so as it moves toward one side in the tire width direction, The first sipe has a short side that extends from either end of the long side in the tire width direction toward the other first sipe, The other first sipe has a short side that extends from the other end of the long side in the tire width direction toward the first first sipe side, In the second sipe unit, one second sipe and the other second sipe constituting the pair of second sipes are arranged facing each other in the circumferential direction of the tire, and each has a long side that extends inclined with respect to the width direction of the tire. The first second sipe has a short side that extends from either end of the long side in the tire width direction toward the other second sipe, The other second sipe has a short side that extends from the other end of the long side in the tire width direction toward the first second sipe, The first sipe unit and the second sipe unit are offset from each other in the tire width direction. The first sipe unit and the second sipe unit are each arranged in a plurality adjacent to each other in the circumferential direction of the tire, forming a first sipe unit row and a second sipe unit row, respectively, and the first sipe unit row and the second sipe unit row are offset from each other in the tire width direction. In the row of the first sipe units, in the plurality of first sipe units, the short sides of one of the plurality of first sipes extend along the same straight line along the circumferential direction of the tire, and the short sides of the other of the plurality of first sipes extend along the same straight line along the circumferential direction of the tire. A tire in which, in the plurality of second sipe units within the row of second sipe units, the short sides of one of the plurality of second sipes extend in the same straight line along the circumferential direction of the tire, and the short sides of the other plurality of second sipes extend in the same straight line along the circumferential direction of the tire. [Claim 2] A tire having at least one land portion on the tread surface of the tire, At least one of the land portions is provided with a first sipe unit consisting of a pair of first sipes and a second sipe unit consisting of a pair of second sipes. Both the first and second sipes terminate within the land area. In the first sipe unit, one first sipe and the other first sipe constituting the pair of first sipes are arranged facing each other in the tire circumferential direction, and each has a long side that extends inclined with respect to the tire width direction so as it moves toward one side in the tire width direction, The first sipe has a short side that extends from either end of the long side in the tire width direction toward the other first sipe, The other first sipe has a short side that extends from the other end of the long side in the tire width direction toward the first first sipe side, In the second sipe unit, one second sipe and the other second sipe constituting the pair of second sipes are arranged facing each other in the circumferential direction of the tire, and each has a long side that extends inclined with respect to the width direction of the tire. The first second sipe has a short side that extends from either end of the long side in the tire width direction toward the other second sipe, The other second sipe has a short side that extends from the other end of the long side in the tire width direction toward the first second sipe, The first sipe unit and the second sipe unit are offset from each other in the tire width direction. The first sipe unit and the second sipe unit are each arranged in a plurality adjacent to each other in the circumferential direction of the tire, forming a first sipe unit row and a second sipe unit row, respectively, and the first sipe unit row and the second sipe unit row are offset from each other in the tire width direction. A tire in which the first sipe unit in the first row of sipe units and the second sipe unit in the second row of sipe units are positioned with a predetermined phase offset from each other in the circumferential direction of the tire. [Claim 3] In the first row of sipe units and the second row of sipe units that are adjacent in the tire width direction, Among the short sides of one of the first sipes or the other first sipes in the row of the first sipes, the short side of the plurality of first sipes in the row of the first sipes is located on the side of the row of the second sipes, The tire according to claim 1 or 2, wherein, of the plurality of second sipe units in the second sipe unit row, the short side of one second sipe or the short side of the other second sipe, which is located on the side of the first sipe unit row, extends in the same straight line along the circumferential direction of the tire. [Claim 4] In the first sipe unit, the one first sipe and the other first sipe each have their short sides extending along the circumferential direction of the tire. The tire according to claim 2, wherein in the second sipe unit, the short side of one second sipe and the other second sipe each extends along the circumferential direction of the tire. [Claim 5] In the first sipe unit, the long sides and short sides of the one first sipe and the other first sipe extend parallel to each other, and the one first sipe and the other first sipe are offset from each other in the tire width direction. The tire according to any one of claims 1 to 4, wherein in the second sipe unit, the long sides and short sides of one second sipe and the other second sipe extend parallel to each other, and the one second sipe and the other second sipe are offset from each other in the tire width direction. [Claim 6] In the first sipe unit, the angle between the long side and the short side of each of the first sipes is 90° or greater. The tire according to any one of claims 1 to 5, wherein in the second sipe unit, the angle between the long side and the short side of the one second sipe and the other second sipe, where the two sides face each other, is 90° or more. [Claim 7] In the first sipe unit, one first sipe and the other first sipe are congruent to each other. The tire according to any one of claims 1 to 6, wherein in the second sipe unit, one second sipe and the other second sipe are congruent to each other. [Claim 8] In the first sipe unit, the ratio of the length of the long side to the length of the short side to the length of the other first sipe is 1 to 15. The tire according to any one of claims 1 to 7, wherein in the second sipe unit, the ratio of the length of one second sipe and the other second sipe along the direction of extension of the long side to the length along the direction of extension of the short side is 1 to 15. [Claim 9] The first sipe unit has a ratio of the tire circumferential length along the tire circumferential direction to the tire width direction, which is 0.1 to 2.

6. The tire according to any one of claims 1 to 8, wherein the ratio of the circumferential length of the tire along the tire's circumferential direction to the length along the tire's width direction is 0.1 to 2.6.

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