tire

Abstract

To improve pin-fallout resistance, and stable steering performance on a snow and ice covered road surface.SOLUTION: A pneumatic tire 1 comprises: a plurality of first blocks 24A arranged in one first region A in the tire width direction with a tire equatorial plane CL as a boundary in a tread portion 2; and a plurality of second blocks 24B arranged in the other second region B in the tire width direction with the tire equatorial plane CL as a boundary in the tread portion 2. A stud pin 8 is installed in a tire grounding surface 21 of the first block 24A and the second block 24B. The first block 24A has a long shape in the tire circumferential direction, and circumferential raws lined in the tire circumferential direction are arranged in a zigzag in the tire width direction, and an outer circumferential groove 22o provided between each of the circumferential raws is formed in a meandering manner.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to tires. [Background technology]

[0002] For example, Patent Document 1 discloses a tire (pneumatic tire) in which a plurality of blocks are formed in the tread and a plurality of pins are attached to each block. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4556682 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, it is desired to improve pin drop resistance and steering stability on harder icy and snowy road surfaces.

[0005] An object of the present invention is to provide a tire that can improve pin drop resistance and steering stability on icy and snowy road surfaces. [Means for solving the problem]

[0006] In order to achieve the above object, a tire according to one aspect of the present invention is a tire comprising a plurality of first blocks arranged in a first region in the tread portion in the tire width direction, the boundary of which is the tire equatorial plane, and a plurality of second blocks arranged in a second region in the tread portion in the tire width direction, the second region being bounded by the tire equatorial plane, and in which stud pins are attached to the tire contact surfaces of the first blocks and the second blocks, the first blocks having an elongated shape in the tire circumferential direction, and a plurality of circumferential rows arranged in the tire circumferential direction in a staggered pattern in the tire width direction, and circumferential grooves provided between each of the circumferential rows are formed in a serpentine pattern.

[0007] It is preferable that the second blocks have a shape that is elongated in the tire width direction, are arranged in a row in the tire circumferential direction, have one end intersecting the tire ground contact edge, and have the other end terminating within the second region.

[0008] It is preferable that the first block located on the innermost side in the tire width direction across the circumferential groove has a distance X1 from the tire equatorial surface to the groove wall of the circumferential groove closest to the tire equatorial surface, with respect to the tire ground contact width TW, in a range of 10%≦X1 / TW≦35%; and the first block located on the outermost side in the tire width direction across the circumferential groove has a distance X2 from the tire equatorial surface to the groove wall of the circumferential groove farthest from the tire equatorial surface, with respect to the tire ground contact width TW, in a range of 16%≦X2 / TW≦40%.

[0009] The first block has two circumferential rows, and when the shortest distance from the tire equatorial plane in the circumferential row closer to the tire equatorial plane is D1, the interval between the staggered rows in the tire width direction is Db1, and the shortest distance from the tire equatorial plane in the circumferential row farther from the tire equatorial plane is D2, and the interval between the staggered rows in the tire width direction is Db2, with respect to the tire contact width TW, 0[%] <Db1 / TW≦15[%] 0[%] <Db2 / TW≦15[%] 0%≦D1 / TW≦25% 15%≦D2 / TW≦39% It is preferable that the following relationship is satisfied.

[0010] It is preferable that the first block has a maximum ground contact width Wb1 in the tire width direction, where Wb1 is the tire ground contact width TW, satisfying the relationship 10[%]≦Wb1 / TW≦25[%].

[0011] It is preferable that the first blocks have a maximum circumferential contact length Lb1 that satisfies the relationship 45[%]≦Lb1 / P1≦95[%] relative to the circumferential pitch P1 of the first blocks.

[0012] It is preferable that the first block has a step portion in which the edge portion in the tire width direction is offset in the tire width direction, and that the maximum ground contact width Wb1 of the first block in the tire width direction and the protruding width G1 of the step portion satisfy the relationship 1[%]≦G1 / Wb1≦40[%], and that the maximum ground contact length Lb1 of the first block in the tire circumferential direction and the protruding length Le1 of the step portion satisfy the relationship 1[%]≦Le1 / Lb1≦50[%].

[0013] The second block preferably has a zigzag shape in the extending direction and a constant width. [Effects of the Invention]

[0014] According to the present invention, it is possible to improve pin drop resistance and steering stability on icy and snowy road surfaces. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a meridian cross-sectional view of a pneumatic tire according to an embodiment. [Figure 2] FIG. 2 is a plan view of a portion of the pneumatic tire according to the embodiment. [Figure 3] FIG. 3 is a partially enlarged plan view of the pneumatic tire according to the embodiment. [Figure 4] FIG. 4 is a partially enlarged plan view of the pneumatic tire according to the embodiment. [Figure 5] FIG. 5 is a partially enlarged plan view of the pneumatic tire according to the embodiment. [Figure 6] FIG. 6 is a table showing the results of a performance test of the pneumatic tire according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of a pneumatic tire according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to this embodiment. Furthermore, the components of this embodiment include those that can be substituted and are obvious substitutes while maintaining the identity of the invention. Furthermore, the multiple modifications described in this embodiment can be arbitrarily combined within the scope obvious to those skilled in the art.

[0017] Fig. 1 is a meridian cross-sectional view of a pneumatic tire according to an embodiment, and Fig. 2 is a plan view of a portion of the pneumatic tire according to an embodiment.

[0018] In the following description, a pneumatic tire 1 will be used as an example of a tire according to the present invention. The pneumatic tire 1, which is an example of a tire, can be filled with air, an inert gas such as nitrogen, or other gases.

[0019] In the following description, the tire radial direction refers to the direction perpendicular to the tire rotational axis (not shown), which is the rotational axis of the pneumatic tire 1. The tire radially inner side refers to the side toward the tire rotational axis in the tire radial direction, and the tire radially outer side refers to the side away from the tire rotational axis in the tire radial direction. The tire circumferential direction refers to the direction around the tire rotational axis as the central axis. The tire width direction refers to the direction parallel to the tire rotational axis. The tire width inner side refers to the side toward the tire equatorial plane (tire equator line) CL in the tire width direction, and the tire width outer side refers to the side away from the tire equatorial plane CL in the tire width direction. The tire equatorial plane CL is a plane that is perpendicular to the tire rotational axis and passes through the center of the tire width of the pneumatic tire 1. The tire equatorial plane CL coincides in position in the tire width direction with the tire width centerline, which is the center position of the pneumatic tire 1 in the tire width direction. The tire width is the width in the tire width direction between the outermost portions in the tire width direction, i.e., the distance between the portions farthest from the tire equatorial plane CL in the tire width direction. The tire equator line refers to a line that is on the tire equatorial plane CL and extends along the tire circumferential direction of the pneumatic tire 1.

[0020] In this embodiment, the pneumatic tire 1 is a winter tire (tire for snow and ice) having stud pins 8.

[0021] 1, the pneumatic tire 1 includes a tread portion 2, a sidewall portion 3, a bead portion 4, and an inner liner 5. The pneumatic tire 1 also includes, as an internal structure, a carcass layer 6 and a belt layer 7.

[0022] The tread portion 2 is provided at the radially outermost portion of the pneumatic tire 1 when viewed in a meridian cross section. The tread portion 2 is made of a rubber composition. The surface of the tread portion 2, i.e., the portion that comes into contact with the road surface when a vehicle (not shown) equipped with the pneumatic tire 1 is traveling, is formed as a tire contact patch 21, and constitutes part of the contour of the pneumatic tire 1. The tread portion 2 has a plurality of circumferential grooves 22 extending in the tire circumferential direction and a plurality of widthwise grooves 23 extending in the tire width direction formed in the tire contact patch 21. The plurality of circumferential grooves 22 are arranged side by side in the tire width direction, and the plurality of widthwise grooves 23 are arranged side by side in the tire circumferential direction. The circumferential grooves 22 and widthwise grooves 23 define a plurality of blocks 24 forming land portions in the tread portion 2. The blocks 24 include the tire contact patch 21 on their surfaces.

[0023] The sidewall portions 3 are provided extending radially inward at both outer ends in the tire width direction of the tread portion 2. The sidewall portions 3 are made of a rubber composition. The sidewall portions 3 form the portions of the pneumatic tire 1 that are most exposed outward in the tire width direction on both sides in the tire width direction.

[0024] The bead portion 4 is provided on the radially inner side of each sidewall portion 3. Each bead portion 4 includes a bead core 41 and a bead filler 42. The bead core 41 is an annular member formed by bundling bead wires, which are steel wires, into a circular shape in the circumferential direction of the tire. The bead filler 42 is a rubber composition that is disposed on the radially outer side of the bead core 41.

[0025] The inner liner 5 is disposed along the inside of the tread portion 2, the sidewall portion 3, and the bead portion 4, and forms the tire inner surface which is the inner surface of the pneumatic tire 1.

[0026] The carcass layer 6 has both ends in the tire width direction folded back from the inner side in the tire width direction to the outer side in the tire width direction at the bead cores 41 of the pair of bead portions 4, and is wound around the tire circumferential direction in a toroidal shape to form the tire skeleton. The carcass layer 6 is made up of a plurality of carcass cords (not shown) arranged in parallel at an angle to the tire circumferential direction along the tire meridian direction and covered with coating rubber. The carcass cords are made of organic fibers (such as polyester, rayon, or nylon). The carcass layer 6 is provided in at least one layer.

[0027] The belt layer 7 has a multi-layer structure in which at least two belt layers 71 are laminated, and is disposed radially outward of the carcass layer 6 in the tread portion 2, covering the carcass layer 6 in the tire circumferential direction. The belt 71 is made of a plurality of cords (not shown) arranged side by side at a predetermined angle relative to the tire circumferential direction, covered with a coating rubber. The cords are made of steel or organic fibers (such as polyester, rayon, or nylon). The overlapping belts 71 are disposed so that the cords cross each other.

[0028] The pneumatic tire 1 of the embodiment includes stud pins 8. Stud holes 25 are formed in the tire contact surface 21 of each block 24 of the tread portion 2. The stud pins 8 are inserted into these stud holes 25, with portions of the stud pins 8 protruding from the tire contact surface 21. The stud holes 25 are formed together with the blocks 24, for example, in the vulcanization process, which is one of the manufacturing processes for the pneumatic tire 1. Alternatively, the stud holes 25 may be formed by drilling or other machining of the tire contact surface 21 of the blocks 24 after the vulcanization process. The stud pins 8 (stud holes 25) are positioned in the center of the width of each block 24 in the extension direction, and multiple stud pins 8 (stud holes 25) are arranged at equal intervals along the longitudinal extension direction.

[0029] In the pneumatic tire 1 of the embodiment, the tread portion 2 has a first region A on one side in the tire width direction, with the tire equatorial plane CL as the boundary, and a second region B on the other side.

[0030] The mounting direction of the pneumatic tire 1 of the embodiment relative to a vehicle is specified. That is, when the pneumatic tire 1 of the embodiment is mounted on a vehicle, the orientations relative to the outer and inner sides of the vehicle in the tire width direction are specified. Although not explicitly shown in the drawings, the orientation specification is indicated, for example, by an indicator provided on the sidewall portion 3. Therefore, when mounted on a vehicle, the side facing the outer side of the vehicle is the outer side of the vehicle, and the side facing the inner side of the vehicle is the inner side of the vehicle. Note that the designation of the outer side and inner side of the vehicle is not limited to when mounted on a vehicle. For example, when mounted on a rim, the orientation of the rim relative to the outer side and inner side of the vehicle in the tire width direction is determined. Therefore, when mounted on a rim, the orientation of the pneumatic tire 1 relative to the outer side and inner side of the vehicle is specified in the tire width direction.

[0031] In the pneumatic tire 1 of the embodiment, a first region A of the tread portion 2 is disposed on the vehicle inner side, and a second region B is disposed on the vehicle outer side. The tread portion 2 has a tread pattern that is asymmetrical with respect to the tire equatorial plane CL.

[0032] A plurality of first blocks 24A (24) are provided in the first region A. A plurality of second blocks 24B (24) are provided in the second region B. In the pneumatic tire 1 of the embodiment, circumferential grooves 22 (hereinafter also referred to as central circumferential grooves 22c) are formed along the tire equatorial plane CL, and the blocks 24 provided on the first region A side with the central circumferential groove 22c on the tire equatorial plane CL as a boundary are the first blocks 24A, and the blocks 24 provided on the second region B side with the central circumferential groove 22c as a boundary are the second blocks 24B.

[0033] The first blocks 24A are formed in the first region A and separated in the tire width direction by a central circumferential groove 22c on the tire equatorial plane CL and a circumferential groove 22 (hereinafter also referred to as an outer circumferential groove 22o) provided on the outer side of the central circumferential groove 22c in the tire width direction. The first blocks 24A are also formed and separated in the tire circumferential direction by widthwise grooves 23. One end of the widthwise groove 23 extending in the tire width direction is connected to the central circumferential groove 22c, and the other end is provided open at the outer end of the tread portion 2 in the tire width direction. Therefore, the first blocks 24A form a circumferential row aligned in the tire circumferential direction.

[0034] The first blocks 24A have a shape that is elongated in the tire circumferential direction. That is, the first blocks 24A have a shape that has a tire circumferential dimension that is larger than the tire width direction dimension. The first blocks 24A are arranged in a single circumferential row in a staggered manner in the tire width direction while being aligned in the tire circumferential direction. The outer circumferential grooves 22o between multiple (two in this embodiment) circumferential rows of the first blocks 24A aligned in the tire width direction extend in the tire circumferential direction and are formed to meander and be offset in the tire width direction.

[0035] According to the pneumatic tire 1 of the embodiment, the first blocks 24A, due to their shape and arrangement, can ensure strong rigidity against collapse in the tire circumferential direction and tire width direction. As a result, the pneumatic tire 1 of the embodiment can reduce the loss of stud pins 8 during driving, improving pin loss resistance. Furthermore, the first blocks 24A have a greater number of stud pins 8 arranged in the tire contact patch 21 in the longitudinal direction. Furthermore, the first blocks 24A have outer circumferential grooves 22o between circumferential rows that extend in the tire circumferential direction but are offset in a meandering manner in the tire width direction, so that the stud pins 8 are arranged at an angle with respect to the tire circumferential direction, allowing the stud pins 8 to be dispersed in the tire width direction. As a result, the pneumatic tire 1 of the embodiment can improve steering stability on icy and snowy roads.

[0036] The second blocks 24B have a shape that is elongated in the tire width direction in the second region B. That is, the second blocks 24B have a shape whose tire widthwise dimension is larger than its circumferential dimension. The second blocks 24B are formed continuously from the tire ground contact edge T on the second region B side toward the tire equatorial plane CL. One end of each second block 24B intersects with the tire ground contact edge T, and the other end terminates in the second region B and extends to the central circumferential groove 22c. A plurality of second blocks 24B are arranged side by side in the tire circumferential direction. Therefore, the widthwise grooves 23 formed between the second blocks 24B in the tire circumferential direction are continuous in the tire width direction in the second region B, with one end opening at the tire ground contact edge T and the other end communicating with the central circumferential groove 22c.

[0037] Here, the tire contact edges T refer to the outermost ends in the tire width direction in the region where the tire contact surface 21 of the tread portion 2 of the pneumatic tire 1 comes into contact with the road surface (horizontal plane) when the pneumatic tire 1 is mounted on a standard rim, inflated to a standard internal pressure, and subjected to 70% of the standard load, and these are continuous in the tire circumferential direction. The tire widthwise dimension between the tire contact edges T is called the tire contact width TW. The standard rim is the "standard rim" specified by JATMA, the "design rim" specified by TRA, or the "measuring rim" specified by ETRTO. The standard internal pressure is the "maximum air pressure" specified by JATMA, the maximum value described in the "tire load limits at various cold inflation pressures" specified by TRA, or the "inflation pressures" specified by ETRTO. In addition, the normal load is the "maximum load capacity" specified by JATMA, the maximum value stated in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified by TRA, or the "LOAD CAPACITY" specified by ETRTO.

[0038] According to the pneumatic tire 1 of the embodiment, the shape and arrangement of the first blocks 24A in the first region A, as well as the shape and arrangement of the second blocks 24B in the second region B, ensures high rigidity of the tread portion 2 as a whole against collapse in the tire circumferential direction and tire width direction when a vehicle equipped with the pneumatic tire 1 of the embodiment travels straight or turns. As a result, the pneumatic tire 1 of the embodiment can reduce the loss of stud pins 8 during driving and improve pin loss resistance. Moreover, according to the pneumatic tire 1 of the embodiment, the second blocks 24B increase the number of stud pins 8 arranged in the tire contact patch 21 in the long tire width direction. As a result, the pneumatic tire 1 of the embodiment can further improve steering stability on icy and snowy roads by synergizing with the increased number of stud pins 8 arranged in the tire circumferential direction in the first blocks 24A. Furthermore, by terminating the second blocks 24B within the second region B, a central circumferential groove 22c can be provided on the tire equatorial plane CL. As a result, the pneumatic tire 1 of the embodiment can improve snow removal performance on the tire equatorial plane CL, which is effective for snow removal, and can further improve steering stability on icy and snowy roads. Furthermore, the pneumatic tire 1 of the embodiment has one end of the widthwise grooves 23 that is open at the tire ground contact edge T and the other end that is connected to the central circumferential groove 22c, so it can improve snow removal performance and further improve steering stability on icy and snowy roads.

[0039] FIG. 3 is a partially enlarged plan view of the pneumatic tire according to the embodiment.

[0040] As shown in FIG. 3, in the pneumatic tire 1 of the embodiment, in the first block 24A, the first block 24A located at the innermost in the tire width direction with the outer circumferential groove 22o therebetween has a distance X1 between the groove wall 22a of the outer circumferential groove 22o closest to the tire equatorial plane CL and the tire equatorial plane CL, which is in the range of 10[%]≦X1 / TW≦35[%] with respect to the tire contact width TW. Also, in the first block 24A, the first block 24A located at the outermost in the tire width direction with the outer circumferential groove 22o therebetween has a distance X2 between the groove wall 22b of the outer circumferential groove 22o farthest from the tire equatorial plane CL and the tire equatorial plane CL, which is in the range of 16[%]≦X2 / TW≦40[%] with respect to the tire contact width TW. The positions of the groove walls 22a and 22b of the outer circumferential groove 22o are the positions on the tire contact surface 21 and are also the positions of the edge portions of the tire contact surface 21 of the first block 24A. Note that the distances X1 and X2 of each first block 24A are in the relationship of X1 < X2.

[0041] According to the pneumatic tire 1 of the embodiment, for each first block 24A located at the innermost and outermost in the tire width direction with the outer circumferential groove 22o therebetween, by setting the distances X1 and X2 between the positions of the ends of the tire contact surface 21 based on the outer circumferential groove 22o and the tire equatorial plane CL within the above ranges with respect to the tire contact width TW, the balance of the arrangement of the stud pins 8 of each first block 24A can be made suitable. As a result, the pneumatic tire 1 of the embodiment can improve the handling stability performance on an icy or snowy road surface.

[0042] FIG. 4 is a partially enlarged plan view of the pneumatic tire according to the embodiment.

[0043] As shown in FIG. 4, in the pneumatic tire 1 of the embodiment, the first block 24A has two circumferential rows as described above. Let the shortest distance from the tire equatorial plane CL in the circumferential row close to the tire equatorial plane CL be D1, and the stagger-type tire width direction interval be Db1. Also, let the shortest distance from the tire equatorial plane CL in the circumferential row far from the tire equatorial plane CL be D2, and the stagger-type tire width direction interval be Db2. In this case, Db1, Db2, D1, and D2 satisfy the relationships of 0[%]<Db1 / TW≦15[%], 0[%]<Db2 / TW≦15[%], 0[%]≦D1 / TW≦25[%], and 15[%]≦D2 / TW≦39[%] with respect to the tire contact width TW.

[0044] According to the pneumatic tire 1 of the embodiment, due to the relationships of Db1, Db2, D1, and D2 with respect to the tire contact width TW, the first blocks 24A are arranged at mutually different distances with respect to the tire equatorial plane CL. Here, by increasing Db1 and Db2 with respect to the tire contact width TW, the overlap of the stud pins 8 in the tire circumferential direction can be suppressed, and the handling stability performance on an icy or snowy road surface can be improved. Also, since Db1 and Db2 are not too large with respect to the tire contact width TW, the division of the circumferential groove 22 in the tire width direction is suppressed, and a decrease in the snow removal performance is suppressed. Further, by increasing D1 and D2 with respect to the tire contact width TW, the arrangement of the stud pins 8 in the first region A is ensured, and since D1 and D2 are not too large with respect to the tire contact width TW, the arrangement of the stud pins 8 in the second region B is ensured, and the handling stability performance on an icy or snowy road surface can be improved.

[0045] Note that the relationships of Db1, Db2, D1, and D2 with respect to the tire contact width TW preferably satisfy the relationships of 0[%]<Db1 / TW≦6[%], 0[%]<Db2 / TW≦6[%], 0[%]≦D1 / TW≦5[%], and 17[%]≦D2 / TW≦24[%] in order to obtain the above effects significantly. Also, the relationships of Db1, Db2, D1, and D2 with respect to the tire contact width TW preferably satisfy the relationships of 1[%]≦Db1 / TW≦2[%], 1[%]≦Db2 / TW≦2[%], 2[%]≦D1 / TW≦3[%], and 22[%]≦D2 / TW≦23[%] in order to obtain the above effects more significantly.

[0046] As shown in FIG. 4, in the pneumatic tire 1 of the embodiment, the first blocks 24A have a maximum ground contact width Wb1 in the tire width direction that satisfies the relationship 10%≦Wb1 / TW≦25% with respect to the tire ground contact width TW.

[0047] According to the pneumatic tire 1 of this embodiment, by making the maximum ground contact width Wb1 larger relative to the tire ground contact width TW, it is possible to suppress collapse of the first blocks 24A and improve the pin pull-out resistance of the stud pins 8. Furthermore, by making the maximum ground contact width Wb1 not too large relative to the tire ground contact width TW, the groove area of ​​the circumferential grooves 22 is secured and a decrease in snow removal performance is suppressed. As a result, the pneumatic tire 1 of this embodiment can further improve pin pull-out resistance and steering stability on icy and snowy roads.

[0048] The relationship of maximum ground contact width Wb1 to tire ground contact width TW preferably satisfies the relationship 9[%]≦Wb1 / TW≦19[%] in order to further improve pin drop resistance and steering stability on icy and snowy roads. Also, the relationship of maximum ground contact width Wb1 to tire ground contact width TW preferably satisfies the relationship 16[%]≦Wb1 / TW≦17[%] in order to further improve pin drop resistance and steering stability on icy and snowy roads.

[0049] Also, as shown in FIG. 4, in the pneumatic tire 1 of the embodiment, the maximum circumferential contact length Lb1 of the first block 24A satisfies the relationship 45[%]≦Lb1 / P1≦95[%] with respect to the circumferential pitch P1 of the first block 24A.

[0050] In the pneumatic tire 1 of this embodiment, by making the maximum ground contact length Lb1 larger relative to the pitch P1, the rigidity of the first blocks 24A in the tire circumferential direction is ensured, which suppresses collapse and improves the pin pull-out resistance of the stud pins 8. Furthermore, by making the maximum ground contact length Lb1 not too large relative to the pitch P1, the groove area of ​​the widthwise grooves 23 between the circumferential direction of the tire is ensured, which prevents a decrease in snow removal performance. As a result, the pneumatic tire 1 of this embodiment can further improve pin pull-out resistance and steering stability on icy and snowy roads.

[0051] The relationship of maximum contact length Lb1 to pitch P1 preferably satisfies the relationship 50[%]≦Lb1 / P1≦91[%] to further improve pin drop resistance and steering stability on icy and snowy roads.The relationship of maximum contact length Lb1 to pitch P1 preferably satisfies the relationship 75[%]≦Lb1 / P1≦85[%] to further improve pin drop resistance and steering stability on icy and snowy roads.

[0052] FIG. 5 is a partially enlarged plan view of the pneumatic tire according to the embodiment.

[0053] As shown in Fig. 5, in the pneumatic tire 1 of the embodiment, the first block 24A has a stepped portion 24Ab in which an edge portion in the tire width direction is offset in the tire width direction between one side and the other side in the tire circumferential direction. Specifically, the first block 24A has a rectangular base portion 24Aa that is long in the tire circumferential direction. The first block 24A has stepped portions 24Ab that protrude to opposite sides in the tire width direction on one side and the other side in the tire circumferential direction of the base portion 24Aa. As a result, the first block 24A has the stepped portion 24Ab that is offset in the tire width direction. The stepped portion 24Ab protrudes obliquely in the tire circumferential direction from the rectangular base portion 24Aa, with the most protruding edge portion being formed along the tire circumferential direction.

[0054] 5, in the pneumatic tire 1 of the embodiment, the maximum ground contact width Wb1 of the first block 24A in the tire width direction and the protruding width G1 of the stepped portion 24Ab in the tire width direction satisfy the relationship 1[%]≦G1 / Wb1≦40[%]. Also, in the pneumatic tire 1 of the embodiment, the maximum ground contact length Lb1 of the first block 24A in the tire circumferential direction and the protruding length Le1 of the stepped portion 24Ab in the tire circumferential direction satisfy the relationship 1[%]≦Le1 / Lb1≦50[%].

[0055] In the pneumatic tire 1 of the embodiment, by making the protrusion width G1 larger relative to the maximum contact width Wb1, the rigidity of the first blocks 24A in the tire width direction is ensured, which suppresses collapse and improves the pin drop resistance of the stud pins 8. Furthermore, by making the protrusion width G1 not too large relative to the maximum contact width Wb1, the groove area of ​​the circumferential grooves 22 between the blocks in the tire width direction is ensured, and deterioration of snow removal performance is suppressed. As a result, the pneumatic tire 1 of the embodiment can further improve pin drop resistance and steering stability on icy and snowy roads. Furthermore, by making the protrusion length Le1 larger relative to the maximum contact length Lb1, the rigidity of the first blocks 24A in the tire circumferential direction is ensured, which suppresses collapse and improves the pin drop resistance of the stud pins 8. By making the protrusion length Le1 not too large relative to the maximum contact length Lb1, the groove area of ​​the circumferential grooves 22 between the blocks in the tire width direction is ensured, and deterioration of snow removal performance is suppressed. As a result, the pneumatic tire 1 of the embodiment can further improve pin drop resistance and steering stability on icy and snowy roads.

[0056] The relationship of the protrusion width G1 to the maximum contact width Wb1 preferably satisfies the relationship 2%≦G1 / Wb1≦35% in order to further improve pin drop resistance and steering stability on icy and snowy roads. The relationship of the protrusion width G1 to the maximum contact width Wb1 preferably satisfies the relationship 18%≦G1 / Wb1≦21% in order to further improve pin drop resistance and steering stability on icy and snowy roads. The relationship of the protrusion length Le1 to the maximum contact length Lb1 preferably satisfies the relationship 10%≦Le1 / Lb1≦50% in order to further improve pin drop resistance and steering stability on icy and snowy roads. The relationship of the protrusion length Le1 to the maximum contact length Lb1 preferably satisfies the relationship 30%≦Le1 / Lb1≦50% in order to further improve pin drop resistance and steering stability on icy and snowy roads.

[0057] As shown in FIG. 5, the pneumatic tire 1 of this embodiment has the above-mentioned stepped portion 24Ab, resulting in an overall circumferentially tilted arrangement. The stud holes 25, in which the stud pins 8 are placed, are arranged at a tilt in the circumferential direction of the tire in accordance with this tilted arrangement. The tilt angle θ of the stud holes 25 (stud pins 8) in the circumferential direction of the tire is preferably in the range of 3°≦θ≦45°. By increasing the angle θ, overlapping of the stud pins 8 in the circumferential direction of the tire can be suppressed, improving steering stability on icy and snowy roads. Furthermore, by not making the angle θ too large, the rigidity of the first blocks 24A in the circumferential direction of the tire can be ensured, which suppresses collapse and improves pin pull-out resistance of the stud pins 8. The angle θ is preferably in the range of 15°≦θ≦20° to further improve pin pull-out resistance and steering stability on icy and snowy roads.

[0058] 2, in the pneumatic tire 1 of the embodiment, the second blocks 24B have a zigzag shape in the extension direction and a constant width Wc. The extension direction of the second blocks 24B is inclined with respect to the tire width direction, and a plurality of stud holes 25 for locating stud pins 8 are arranged at the center of the width Wc along the extension direction. The second blocks 24B have a zigzag shape in the tire circumferential direction in this extension direction.

[0059] In the pneumatic tire 1 of the embodiment, the zigzag shape of the second blocks 24B enhances the edge effect and improves steering stability on snowy and icy roads. Also, in the pneumatic tire 1 of the embodiment, the width Wc of the second blocks 24B is constant in the extension direction, which makes the ground contact pressure uniform at each portion in the extension direction of the second blocks 24B and also makes the deformation of the second blocks 24B uniform, thereby improving pin pull-out resistance.

[0060] In the above embodiment, the pneumatic tire 1 has been described as an example of a tire. However, the present invention is not limited to this, and the configuration described in the embodiment can be applied to any other tire within the scope of what is obvious to a person skilled in the art. Examples of other tires include airless tires. [Example]

[0061] 6 is a table showing the results of a performance test of the pneumatic tire according to the embodiment. Performance evaluation tests conducted on a conventional pneumatic tire and the pneumatic tire according to the embodiment will be described below. The performance evaluation tests were conducted on straight-line performance and cornering performance, which are steering stability on snowy and icy roads, and the number of pin loss, which is pin loss resistance.

[0062] The test conditions were as follows: a test tire with a tire size of 150 / 650R15 was mounted on a rim with a rim size of 15x7J, inflated to an internal pressure (200kPa), and mounted on a test vehicle (a four-wheel drive vehicle equipped with a 1600cc class supercharged engine), and the vehicle was driven 200km on a test course with an icy and snowy surface for evaluation. Furthermore, the tire contact width was measured by applying a load of 4.0kN to the test tire, and the maximum width was recorded.

[0063] The evaluation method for straight-line running performance and cornering performance (steering stability on snowy and icy roads) was to quantify the subjective evaluation by the driver during the above-mentioned driving. This evaluation was carried out using an index rating with the conventional example as the standard (100), and the higher the number, the better the straight-line running performance and cornering performance.

[0064] The number of stud pins that came out (anti-pin pull performance) was evaluated by counting the number of stud pins that came out after the above-mentioned run as an actual value. In this evaluation, the lower the number, the better the anti-pin pull performance.

[0065] A conventional pneumatic tire is shown in Patent Document 1.

[0066] On the other hand, the pneumatic tire of the example has a tread pattern shown in FIG.

[0067] As shown in the test results, the pneumatic tire of the example has improved straight running performance, cornering performance, and pin drop resistance compared to the conventional tire. [Explanation of symbols]

[0068] 1. Pneumatic tires (tires) 2 Tread section 8 stud pins 21 Tire contact surface 22 Circumferential groove 22a Groove wall 22b Groove wall 24A First Block 24B Second Block 24Ab step A First area B Second area CL Tire equatorial plane TW tire contact width

Claims

1. A plurality of first blocks are arranged in a first region in a tread portion in a tire width direction, the first region being bounded by a tire equatorial plane; A plurality of second blocks arranged in the tread portion in another second region in the tire width direction, the second region being bounded by the tire equatorial plane; A tire comprising: a stud pin attached to a tire contact surface of the first block and the second block, The first block has a long shape in the tire circumferential direction, and a plurality of circumferential rows arranged in the tire circumferential direction are arranged in a staggered manner in the tire width direction, and a circumferential groove provided between each of the circumferential rows is formed in a meandering manner, a plurality of the stud pins of the first block are arranged at an inclination in the tire circumferential direction, and an angle θ of inclination in the tire circumferential direction is in the range of 15°≦θ≦20°.

2. 2. The tire according to claim 1, wherein the second blocks have a shape elongated in the tire width direction, are arranged side by side in the tire circumferential direction, and one end portion of the second blocks intersects with a tire ground contact edge and the other end portion terminates within the second region.

3. a first block located at the innermost side in the tire width direction across the circumferential groove has a distance X1 from the tire equatorial plane to a groove wall of the circumferential groove closest to the tire equatorial plane, the distance X1 being in a range of 10%≦X1 / TW≦35% with respect to a tire ground contact width TW, In a first block located at the outermost side in the tire width direction across the circumferential groove, a distance X2 between the groove wall of the circumferential groove farthest from the tire equatorial plane and the tire equatorial plane is in a range of 16%≦X2 / TW≦40% with respect to a tire ground contact width TW.

3. A tire according to claim 1 or 2.

4. The first block has two of the circumferential rows, A shortest distance from the tire equatorial plane in the circumferential row close to the tire equatorial plane is defined as D1, and a tire width direction interval of the staggered pattern is defined as Db1, When the shortest distance from the tire equatorial plane in the circumferential row farthest from the tire equatorial plane is D2 and the interval in the tire width direction of the staggered pattern is Db2, For tire contact width TW, 0[%]<Db1 / TW≦15[%] 0[%]<Db2 / TW≦15[%] 0%≦D1 / TW≦25% 15%≦D2 / TW≦39% The tire according to any one of claims 1 to 3, which satisfies the relationship:

5. 5. The tire according to claim 1, wherein the first block has a maximum ground contact width Wb1 in the tire width direction, and the maximum ground contact width TW of the first block satisfies a relationship of 10%≦Wb1 / TW≦25%.

6. 6. The tire according to claim 1, wherein the first blocks have a maximum ground contact length Lb1 in the tire circumferential direction and a pitch P1 in the tire circumferential direction that satisfies the relationship: 45[%]≦Lb1 / P1≦95[%].

7. The first block has a step portion in which an edge portion in the tire width direction is offset in the tire width direction, a maximum ground contact width Wb1 of the first block in the tire width direction and a protruding width G1 of the step portion satisfy a relationship of 1 [%] ≦ G1 / Wb1 ≦ 40 [%], a maximum ground contact length Lb1 of the first block in the tire circumferential direction and a protruding length Le1 of the step portion satisfy a relationship of 1 [%] ≦ Le1 / Lb1 ≦ 50 [%]; A tire according to any one of claims 1 to 6.

8. The tire according to claim 1 , wherein the second blocks have a zigzag shape in the extending direction and have a constant width.

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