Tire

Abstract

To provide a tire capable of improving wear resistance while ensuring snow and ice performance and wet performance through optimization of the pattern configuration.SOLUTION: In a tire according to the present invention: widthwise grooves 40 include second widthwise grooves 42, which are arranged between an outer circumferential main groove 35 and an inner circumferential main groove 31, and both ends of which in a tire width direction communicate with the outer circumferential main groove 35 and the inner circumferential main groove 31 at positions on extension lines of a shoulder widthwise groove 45 and a center widthwise groove 41, and each have a bent portion 43 with an extension direction thereof changing between the outer circumferential main groove 35 and the inner circumferential main groove 31; independent grooves 50 are arranged in a second land portion 22, and extend in the tire width direction and has both ends terminating within the second land portion 22; and the second widthwise grooves 42 and the independent grooves 50 are arranged alternately in a tire circumferential direction between the outer circumferential main groove 35 and the inner circumferential main groove 31.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a tire. [Background technology]

[0002] Tires mounted on vehicles have grooves formed in the tread portion to ensure various performance characteristics according to the manner in which the tire is used, and performance is improved by devising the shape of the grooves. For example, a pneumatic tire described in Patent Document 1 has a plurality of blocks on the surface of the tread portion, each of which is formed by a plurality of circumferential main grooves and a plurality of lug grooves, and the lug grooves are bent at bending points. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5109734 Summary of the Invention [Problem to be solved by the invention]

[0004] Traditionally, studless tires have been focused on performance on ice, but there is also a demand for improved performance on snow. Generally, improving performance on ice requires improving adhesion friction, but this is achieved by increasing the actual contact area by reducing the groove area ratio, which has the drawback of worsening performance on snow and wet surfaces. In addition, improved wear resistance is also required for studless tires in recent years.

[0005] The present invention has been made in view of the above, and aims to provide a tire that can improve wear resistance while ensuring snow and ice performance and wet performance by optimizing the pattern configuration. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, a tire according to the present invention includes a plurality of circumferential main grooves arranged in a tread portion and extending in a tire circumferential direction, a plurality of widthwise grooves arranged in the tread portion and extending in a tire width direction, and a land portion defined by the circumferential main grooves and the widthwise grooves, wherein the plurality of circumferential main grooves include an outer circumferential main groove arranged outermost in the tire width direction, and an inner circumferential main groove adjacent to the outer circumferential main groove at a position inside the outer circumferential main groove in the tire width direction, and the plurality of widthwise grooves include a shoulder widthwise groove arranged outward in the tire width direction of the outer circumferential main groove and communicating with the outer circumferential main groove, and a shoulder widthwise groove arranged inward in the tire width direction of the inner circumferential main groove, one end of which communicates with the inner circumferential main groove and the other end of which terminates within the land portion. a center widthwise groove; and a second widthwise groove disposed between the outer circumferential main groove and the inner circumferential main groove, the second widthwise groove having both ends in the tire width direction that communicate with the outer circumferential main groove and the inner circumferential main groove at positions on an extension line of the shoulder widthwise groove and an extension line of the center widthwise groove, and having a bent portion whose extending direction changes between the outer circumferential main groove and the inner circumferential main groove, wherein among the plurality of land portions, a second land portion is a land portion whose both sides in the tire width direction are partitioned by the outer circumferential main groove and the inner circumferential main groove, and an independent groove is disposed in the second land portion, the second widthwise groove and the independent groove are disposed alternately in the tire circumferential direction between the outer circumferential main groove and the inner circumferential main groove. [Effects of the Invention]

[0007] The tire according to the present invention has an effect of improving wear resistance while ensuring performance on snow and ice and wet conditions. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a tire meridian cross-sectional view showing a main part of a pneumatic tire according to an embodiment. [Figure 2] FIG. 2 is a view taken along the line AA in FIG. [Figure 3]FIG. 3 is a detailed view of part B in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along CC in FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along the line E-E in FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along the line FF in FIG. [Figure 7] FIG. 7 is an explanatory diagram showing a modified example of the pneumatic tire according to the embodiment, in which the groove width of the independent groove is larger near the first outer circumferential main groove than near the first inner circumferential main groove. [Figure 8] FIG. 8 is an explanatory diagram showing a modified example of the pneumatic tire according to the embodiment, in which the independent grooves have protruding portions in the groove width direction. [Figure 9A] FIG. 9A is a chart showing the results of a performance evaluation test of a pneumatic tire. [Figure 9B] FIG. 9B is a chart showing the results of a performance evaluation test of a pneumatic tire. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of a tire according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are replaceable and easily conceivable by a person skilled in the art, or those that are substantially the same.

[0010] [Embodiment] 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.

[0011] 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 radial inner side refers to the side toward the tire rotational axis in the tire radial direction, and the tire radial 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, and 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 portions located outermost in the tire width direction, that is, the distance in the tire width direction between the portions farthest from the tire equatorial plane CL. 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. In the following description, the tire meridian cross section refers to a cross section of the tire cut by a plane that includes the tire rotation axis.

[0012] FIG. 1 is a tire meridian cross-sectional view showing a main portion of a pneumatic tire 1 according to an embodiment. The pneumatic tire 1 according to this embodiment has a specified mounting direction relative to a vehicle, i.e., the direction when mounted on a vehicle. That is, the side of the pneumatic tire 1 according to this embodiment that faces the inside of the vehicle when mounted on the vehicle is the inside of the vehicle mounting direction, and the side that faces the outside of the vehicle when mounted on the vehicle is the outside of the vehicle mounting direction. Note that the designation of the inside of the vehicle mounting direction and the outside of the vehicle mounting direction is not limited to when mounted on a vehicle. For example, when mounted on a rim, the orientation of the rim relative to the inside and outside 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 inside and outside of the vehicle in the tire width direction is specified. The pneumatic tire 1 also has a mounting direction indicator (not shown) that indicates the mounting direction relative to the vehicle. The mounting direction indicator is configured, for example, by a mark or a concavo-convex shape attached to the sidewall portion 8 of the tire. For example, ECER30 (Article 30 of the Economic Commission for Europe Regulation) requires that a mounting direction indicator be provided on the sidewall portion 8 that is on the outer side in the vehicle mounting direction when mounted on a vehicle. Furthermore, the pneumatic tire 1 according to this embodiment is a pneumatic tire 1 that is mainly used for passenger cars.

[0013] Furthermore, the pneumatic tire 1 according to this embodiment is a pneumatic tire 1 having a specified rotation direction when mounted on a vehicle. That is, the pneumatic tire 1 is mounted on a vehicle so as to rotate in a specified rotation direction about a rotation axis when the vehicle moves forward. The pneumatic tire 1 also has a rotation direction indicator (not shown) that indicates the rotation direction. The rotation direction indicator is configured, for example, by a mark or an unevenness provided on the sidewall portion 8 of the tire. In the following description, the leading side in the tire rotation direction refers to the rotation direction side when the pneumatic tire 1 is rotated in the specified direction, and is the side that comes into contact with or leaves the road surface first when the pneumatic tire 1 is mounted on a vehicle and rotated in the specified direction to travel. The trailing side in the tire rotation direction refers to the opposite side of the rotation direction when the pneumatic tire 1 is rotated in the specified direction, and is the side that comes into contact with or leaves the road surface after the leading side when the pneumatic tire 1 is mounted on a vehicle and rotated in the specified direction to travel.

[0014] When viewed in meridian section, the pneumatic tire 1 according to this embodiment has a tread portion 2 disposed at the radially outermost portion of the tire, and the tread portion 2 has a tread rubber 4 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 tread contact surface 3, and the tread contact surface 3 constitutes part of the contour of the pneumatic tire 1.

[0015] Shoulder portions 5 are located at both outer ends of the tread portion 2 in the tire width direction, and sidewall portions 8 are arranged on the tire radially inward side of the shoulder portions 5. That is, the sidewall portions 8 are arranged on both sides of the tread portion 2 in the tire width direction. In other words, the sidewall portions 8 are arranged in two locations on both sides of the pneumatic tire 1 in the tire width direction, and form the outermost exposed portions of the pneumatic tire 1 in the tire width direction.

[0016] A bead portion 10 is located on the tire radially inner side of each sidewall portion 8 located on both sides in the tire width direction. Like the sidewall portions 8, the bead portions 10 are located at two positions on both sides of the tire equatorial plane CL; that is, a pair of bead portions 10 are located on both sides of the tire equatorial plane CL in the tire width direction. Each bead portion 10 is provided with a bead core 11, and a bead filler 12 is provided on the tire radially outer side of the bead core 11. The bead core 11 is an annular member formed by bundling bead wires, which are steel wires, into a circular shape, and the bead filler 12 is a rubber member located on the tire radially outer side of the bead core 11.

[0017] A belt layer 14 is also disposed in the tread portion 2. The belt layer 14 has a multi-layer structure in which a plurality of belts 141, 142 and a belt cover 143 are laminated. In this embodiment, two layers of belts 141, 142 are laminated. The belts 141, 142 constituting the belt layer 14 are formed by coating a plurality of belt cords made of steel or organic fiber material such as polyester, rayon, or nylon with coating rubber and rolling the coated belt cords. The belt angle, defined as the inclination angle of the belt cords with respect to the tire circumferential direction, is within a predetermined range (for example, 20° to 55°). The two-layer belts 141, 142 have different belt angles. Therefore, the belt layer 14 has a so-called cross-ply structure in which the two-layer belts 141, 142 are laminated with the inclination directions of the belt cords crossing each other. In other words, the two-layer belts 141, 142 are provided as so-called cross belts in which the belt cords of the respective belts 141, 142 are arranged in a direction in which they cross each other.

[0018] The belt cover 143 is formed by covering a plurality of belt cover cords made of steel or organic fiber material such as polyester, rayon, or nylon with coating rubber and rolling the covered cords, and the belt angle, defined as the inclination angle of the belt cover cords with respect to the tire circumferential direction, is within a predetermined range (for example, 0° to 10°). The belt cover 143 is, for example, a strip material formed by covering one or more belt cover cords with coating rubber, and is formed by winding this strip material spirally around the tire rotation axis from the outer side in the tire radial direction of the two-layered belts 141 and 142.

[0019] A carcass layer 13 containing the cords of the radial ply is provided continuously on the tire radially inward side of the belt layer 14 and on the tire equatorial plane CL side of the sidewall portion 8. Therefore, the pneumatic tire 1 according to this embodiment is configured as a so-called radial tire. The carcass layer 13 has a single-layer structure consisting of one carcass ply or a multi-layer structure consisting of a plurality of carcass plies stacked together, and is toroidally spanned between a pair of bead portions 10 arranged on both sides in the tire width direction to form the framework of the tire.

[0020] Specifically, the carcass layer 13 is disposed from one of a pair of bead portions 10 located on both sides in the tire width direction to the other bead portion 10, and is wound back along the bead core 11 at the bead portion 10 toward the outside in the tire width direction so as to enclose the bead core 11 and the bead filler 12. The bead filler 12 is made of a rubber material that is disposed in a space formed on the outside in the tire radial direction of the bead core 11 by folding back the carcass layer 13 at the bead portion 10 in this manner. The belt layer 14 is disposed on the outside in the tire radial direction of the portion of the carcass layer 13 that is positioned in the tread portion 2 and that is stretched between the pair of bead portions 10 in this manner. The carcass ply of the carcass layer 13 is formed by covering a plurality of carcass cords made of steel or an organic fiber material such as aramid, nylon, polyester, or rayon with coating rubber and rolling the coated cords. The carcass cords constituting the carcass ply are arranged in parallel at a certain angle relative to the tire circumferential direction, along the tire meridian direction.

[0021] In the bead portion 10, a rim cushion rubber 17 that forms the contact surface of the bead portion 10 with the rim flange is arranged on the tire radially inner side and tire widthwise outer side of the bead core 11 and the turned-up portion of the carcass layer 13. Furthermore, an inner liner 16 is formed along the carcass layer 13 on the inner side of the carcass layer 13 or on the inner side of the carcass layer 13 in the pneumatic tire 1. The inner liner 16 forms a tire inner surface 18, which is the inner surface of the pneumatic tire 1.

[0022] Fig. 2 is a view taken along the arrow AA in Fig. 1. The tread portion 2 has a plurality of circumferential main grooves 30 extending in the tire circumferential direction and a plurality of widthwise grooves 40 extending in the tire width direction arranged in the tread contact surface 3, and these circumferential main grooves 30 and widthwise grooves 40 define a plurality of land portions 20 on the surface of the tread portion 2. In this embodiment, four circumferential main grooves 30 are arranged side by side in the tire width direction. More specifically, the circumferential main grooves 30 include two inner circumferential main grooves 31 arranged on both sides of the tire equatorial plane CL in the tire width direction, and two outer circumferential main grooves 35 arranged one on each side of the two inner circumferential main grooves 31 in the tire width direction.

[0023] The circumferential main groove 30 here is a longitudinal groove extending in the tire circumferential direction, and has a wear indicator (slip sign) inside that indicates the end of wear. The circumferential main groove 30 thus formed has a groove width in the range of 3.0 mm to 13.0 mm, and a groove depth in the range of 7.0 mm to 10.0 mm.

[0024] The land portions 20 defined by the circumferential main grooves 30 include a center land portion 21, a second land portion 22, and a shoulder land portion 23. Of these, the center land portion 21 is a land portion 20 located between the inner circumferential main grooves 31, and is defined on both sides in the tire width direction by the inner circumferential main grooves 31. The second land portion 22 is a land portion 20 located between the inner circumferential main groove 31 and the outer circumferential main groove 35, which are adjacent in the tire width direction, and is a land portion 20 defined on both sides in the tire width direction by the inner circumferential main groove 31 and the outer circumferential main groove 35. That is, the inner portion of the second land portion 22 in the tire width direction is defined by the inner circumferential main groove 31, and the outer portion in the tire width direction is defined by the outer circumferential main groove 35. The shoulder land portions 23 are land portions 20 located on the outer side of the outer circumferential main groove 35 in the tire width direction, and are defined on the inner side in the tire width direction by the outer circumferential main groove 35. The second land portion 22 and the shoulder land portion 23 are disposed on both sides of the tire equatorial plane CL in the tire width direction.

[0025] Of the four circumferential main grooves 30, the two outer circumferential main grooves 35 are both positioned outermost in the tire width direction and extend in the tire circumferential direction. Of the four circumferential main grooves 30, the two inner circumferential main grooves 31 are both positioned adjacent to the outer circumferential main groove 35 at positions inside the outer circumferential main groove 35 in the tire width direction and extend in the tire circumferential direction. The two outer circumferential main grooves 35 and the two inner circumferential main grooves 31 have different shapes from each other, and the inner circumferential main grooves 31 have different shapes from each other.

[0026] Specifically, when the two outer circumferential main grooves 35 are a first outer circumferential main groove 35a and a second outer circumferential main groove 35b, the first outer circumferential main groove 35a is formed to extend linearly along the tire circumferential direction, while the second outer circumferential main groove 35b is formed to extend circumferentially and oscillate in the tire width direction in a zigzag shape.

[0027] Similarly, when the two inner circumferential main grooves 31 are defined as a first inner circumferential main groove 31a and a second inner circumferential main groove 31b, the first inner circumferential main groove 31a is formed to extend linearly along the tire circumferential direction, while the second inner circumferential main groove 31b is formed to extend circumferentially and oscillate in the tire width direction in a zigzag pattern.

[0028] In this embodiment, the first inner circumferential main groove 31a and the first outer circumferential main groove 35a are the inner circumferential main groove 31 and the outer circumferential main groove 35 that are arranged on the inner side of the tire equatorial plane CL in the vehicle mounting direction, out of the two inner circumferential main grooves 31 and the two outer circumferential main grooves 35 that are arranged on the inner side of the tire equatorial plane CL in the vehicle mounting direction. Also, the second inner circumferential main groove 31b and the second outer circumferential main groove 35b are the inner circumferential main groove 31 and the outer circumferential main groove 35 that are arranged on the outer side of the tire equatorial plane CL in the vehicle mounting direction, out of the two inner circumferential main grooves 31 and the two outer circumferential main grooves 35 that are arranged on the outer side of the tire equatorial plane CL in the vehicle mounting direction.

[0029] The outer circumferential main groove 35 has a first outer circumferential main groove 35a and a second outer circumferential main groove 35b, and the inner circumferential main groove 31 has a first inner circumferential main groove 31a and a second inner circumferential main groove 31b, so that the second land portion 22 has a first second land portion 22a and a second second land portion 22b. That is, the first second land portion 22a has an inner portion in the tire width direction defined by the first inner circumferential main groove 31a and an outer portion in the tire width direction defined by the first outer circumferential main groove 35a, and the second second land portion 22b has an inner portion in the tire width direction defined by the second inner circumferential main groove 31b and an outer portion in the tire width direction defined by the second outer circumferential main groove 35b.

[0030] Similarly, the shoulder land portion 23 has a first shoulder land portion 23a and a second shoulder land portion 23b. That is, the first shoulder land portion 23a is located outward in the tire width direction from the first outer circumferential main groove 35a and its inner side in the tire width direction is defined by the first outer circumferential main groove 35a, while the second shoulder land portion 23b is located outward in the tire width direction from the second outer circumferential main groove 35b and its inner side in the tire width direction is defined by the second outer circumferential main groove 35b.

[0031] The widthwise grooves 40 include a center widthwise groove 41, a second widthwise groove 42, and shoulder widthwise grooves 45. Of these, the center widthwise groove 41 is disposed between the two inner circumferential main grooves 31. The center widthwise groove 41 is disposed on the inner side of the inner circumferential main grooves 31 in the tire width direction, with one end communicating with the inner circumferential main groove 31 and the other end terminating within the land portion 20. More specifically, the center widthwise groove 41 communicates with the first inner circumferential main groove 31a of the two inner circumferential main grooves 31, and the other end terminates within the center land portion 21 at a position between the tire equatorial plane CL and the first inner circumferential main groove 31a. In this embodiment, no widthwise grooves 40 other than the center widthwise groove 41 are disposed between the two inner circumferential main grooves 31, so the center land portion 21 is a rib-shaped land portion 20 formed continuously in the tire circumferential direction.

[0032] The second widthwise grooves 42 are disposed between the inner circumferential main groove 31 and the outer circumferential main groove 35, and both ends in the tire width direction are second widthwise grooves 42 that communicate with the inner circumferential main groove 31 and the outer circumferential main groove 35. More specifically, the second widthwise grooves 42 include a first second widthwise groove 42a that is the second widthwise groove 42 disposed between the first inner circumferential main groove 31a and the first outer circumferential main groove 35a, and a second second widthwise groove 42b that is the second widthwise groove 42 disposed between the second inner circumferential main groove 31b and the second outer circumferential main groove 35b.

[0033] The first second widthwise groove 42a has an inner end in the tire width direction that communicates with the first inner circumferential main groove 31a and an outer end in the tire width direction that communicates with the first outer circumferential main groove 35a. The first second widthwise groove 42a disposed between the first inner circumferential main groove 31a and the first outer circumferential main groove 35a forms a widthwise groove 40 that defines the first second land portion 22a, which is the second land portion 22 located between the first inner circumferential main groove 31a and the first outer circumferential main groove 35a. Therefore, the first second land portion 22a is defined on both sides in the tire width direction by the first inner circumferential main groove 31a and the first outer circumferential main groove 35a, and is defined on both sides in the tire circumferential direction by the first second widthwise groove 42a, forming a block-shaped land portion 20.

[0034] The second second widthwise grooves 42b have inner ends in the tire width direction that communicate with the second inner circumferential main grooves 31b and outer ends in the tire width direction that communicate with the second outer circumferential main grooves 35b. In this case, the second second widthwise grooves 42b have inner ends in the tire width direction that communicate with the curved portions of the second inner circumferential main grooves 31b that oscillate in a zigzag pattern and outer ends in the tire width direction that communicate with the curved portions of the second outer circumferential main grooves 35b that oscillate in a zigzag pattern.

[0035] The second second widthwise groove 42b disposed between the second inner circumferential main groove 31b and the second outer circumferential main groove 35b forms a widthwise groove 40 that defines a second second land portion 22b, which is the second land portion 22 located between the second inner circumferential main groove 31b and the second outer circumferential main groove 35b. Therefore, the second second land portion 22b is defined on both sides in the tire width direction by the second inner circumferential main groove 31b and the second outer circumferential main groove 35b, and is defined on both sides in the tire circumferential direction by the second second widthwise groove 42b, forming a block-shaped land portion 20.

[0036] The shoulder width direction grooves 45 are arranged on the outer side in the tire width direction of the outer circumferential main groove 35, and their inner ends in the tire width direction form width direction grooves 40 that communicate with the outer circumferential main groove 35. In detail, the shoulder width direction grooves 45 include a first shoulder width direction groove 45a that is a shoulder width direction groove 45 arranged on the outer side in the tire width direction of the first outer circumferential main groove 35a, and a second shoulder width direction groove 45b that is a shoulder width direction groove 45 arranged on the outer side in the tire width direction of the second outer circumferential main groove 35b.

[0037] The first shoulder widthwise groove 45a has an inner end in the tire width direction that communicates with the first outer circumferential main groove 35a, and the second shoulder widthwise groove 45b has an inner end in the tire width direction that communicates with the second outer circumferential main groove 35b. In this case, the second shoulder widthwise groove 45b has an inner end in the tire width direction that communicates with a bent portion of the second outer circumferential main groove 35b that oscillates in a zigzag pattern.

[0038] Further, the outer ends of the first shoulder widthwise groove 45a and the second shoulder widthwise groove 45b in the tire width direction terminate at so-called design ends, which are ends of the tread pattern of the tread portion 2 in the tire width direction.

[0039] The first shoulder widthwise groove 45a formed between the first outer circumferential main groove 35a and the design end serves as a widthwise groove 40 that defines the first shoulder land portion 23a, which is the shoulder land portion 23 located on the outer side in the tire width direction of the first outer circumferential main groove 35a. Therefore, the first shoulder land portion 23a is defined on the inner side in the tire width direction by the first outer circumferential main groove 35a, and on both sides in the tire circumferential direction by the first shoulder widthwise groove 45a, forming a block-shaped land portion 20.

[0040] Additionally, the second shoulder widthwise groove 45b formed between the second outer circumferential main groove 35b and the design end serves as a widthwise groove 40 that defines the second shoulder land portion 23b, which is the shoulder land portion 23 located on the outer side in the tire width direction of the second outer circumferential main groove 35b. Therefore, the second shoulder land portion 23b is defined on the inner side in the tire width direction by the second outer circumferential main groove 35b, and on both sides in the tire circumferential direction by the second shoulder widthwise groove 45b, forming a block-shaped land portion 20.

[0041] Of the multiple widthwise grooves 40 arranged in this manner, the first second widthwise groove 42a is connected to the first inner circumferential main groove 31a at a position on an extension line of the center widthwise groove 41, and is connected to the first outer circumferential main groove 35a at a position on an extension line of the first shoulder widthwise groove 45a.

[0042] That is, the opening of the first second widthwise groove 42a relative to the first inner circumferential main groove 31a and the opening of the center widthwise groove 41 relative to the first inner circumferential main groove 31a have portions that are co-located in the tire circumferential direction. Similarly, the opening of the first second widthwise groove 42a relative to the first outer circumferential main groove 35a and the opening of the first shoulder widthwise groove 45a relative to the first outer circumferential main groove 35a have portions that are co-located in the tire circumferential direction.

[0043] The second second widthwise groove 42b also communicates with the second outer circumferential main groove 35b at a position on an extension of the second shoulder widthwise groove 45b. The opening of the second second widthwise groove 42b relative to the second outer circumferential main groove 35b and the opening of the second shoulder widthwise groove 45b relative to the second outer circumferential main groove 35b have portions that are located at the same position in the tire circumferential direction.

[0044] Additionally, an independent groove 50 is arranged in the first second land portion 22a defined by the first inner circumferential main groove 31a and the first outer circumferential main groove 35a. The independent groove 50 extends in the tire width direction, and both ends in the tire width direction terminate within the first second land portion 22a.

[0045] The independent grooves 50 are arranged alternately with the first second widthwise grooves 42a in the tire circumferential direction. That is, the first second widthwise grooves 42a and the independent grooves 50 are arranged alternately in the tire circumferential direction between the first outer circumferential main groove 35a and the first inner circumferential main groove 31a. In other words, a plurality of first second land portions 22a are arranged side by side in the tire circumferential direction between the first inner circumferential main groove 31a and the first outer circumferential main groove 35a, and one independent groove 50 is arranged in each first second land portion 22a.

[0046] Additionally, an inner-land-portion groove 55 is arranged in the second second land portion 22b defined by the second inner-circumferential main groove 31b and the second outer-circumferential main groove 35b. The inner-land-portion groove 55 extends in the tire width direction, with its outer end in the tire width direction communicating with the second outer-circumferential main groove 35b and its inner end in the tire width direction terminating within the second second land portion 22b.

[0047] The inner-land-portion grooves 55 are arranged alternately with the second second widthwise grooves 42b in the tire circumferential direction. That is, the second second widthwise grooves 42b and the inner-land-portion grooves 55 are arranged alternately in the tire circumferential direction between the second outer-side circumferential main groove 35b and the second inner-side circumferential main groove 31b. In other words, a plurality of second second land portions 22b are arranged side by side in the tire circumferential direction between the second inner-side circumferential main groove 31b and the second outer-side circumferential main groove 35b, and one inner-land-portion groove 55 is arranged in each second second land portion 22b.

[0048] Additionally, shoulder narrow grooves 60 extending in the tire circumferential direction are arranged in the shoulder land portions 23 located on the outer side in the tire width direction of the outer circumferential main grooves 35. One end of each shoulder narrow groove 60 extending in the tire circumferential direction is connected to the shoulder width direction groove 45, and the other end terminates within the shoulder land portion 23. The shoulder narrow grooves 60 arranged in the shoulder land portion 23 and located on the same side in the tire width direction with respect to the tire equatorial plane CL all have ends that communicate with the shoulder width direction groove 45 on the same side in the tire circumferential direction. In other words, the shoulder narrow grooves 60 arranged in the shoulder land portions 23 defined by the same outer circumferential main grooves 35 all face the same direction in the tire circumferential direction.

[0049] Specifically, the shoulder narrow groove 60 includes a first shoulder narrow groove 60a disposed in the first shoulder land portion 23a and a second shoulder narrow groove 60b disposed in the second shoulder land portion 23b. The ends of the first shoulder narrow grooves 60a that connect to the first shoulder widthwise groove 45a in the tire circumferential direction are all on the same side for the multiple first shoulder narrow grooves 60a, and the ends that terminate in the first shoulder land portion 23a in the tire circumferential direction are all on the same side for the multiple first shoulder narrow grooves 60a. Similarly, the ends of the second shoulder narrow grooves 60b that connect to the second shoulder widthwise groove 45b in the tire circumferential direction are all on the same side for the multiple second shoulder narrow grooves 60b, and the ends that terminate in the second shoulder land portion 23b in the tire circumferential direction are all on the same side for the multiple second shoulder narrow grooves 60b.

[0050] Furthermore, the first shoulder narrow groove 60a and the second shoulder narrow groove 60b have ends on different sides, one communicating with the shoulder widthwise groove 45 and the other terminating within the shoulder land portion 23. That is, the first shoulder narrow groove 60a and the second shoulder narrow groove 60b are oriented in opposite directions in the tire circumferential direction. Furthermore, the first shoulder narrow groove 60a extends linearly in the tire circumferential direction, whereas the second shoulder narrow groove 60b extends circumferentially but has a portion that bends in the tire width direction.

[0051] Furthermore, a plurality of sipes 70 extending in the tire width direction are arranged in each land portion 20. The sipes 70 arranged in the land portion 20 are, for example, formed in a zigzag pattern by extending in the tire width direction while repeatedly bending and oscillating in the tire circumferential direction. The ends of each sipe 70 may terminate within the land portion 20, or may be connected to other grooves. The sipes 70 arranged in each land portion 20 are preferably inclined in the same direction in the tire circumferential direction with respect to the tire width direction as the widthwise groove 40 that is positioned at the same position in the tire width direction. In other words, each sipe 70 is preferably arranged in a direction extending approximately parallel to the widthwise groove 40 that is positioned at the same position in the tire width direction.

[0052] By arranging sipes 70 on each land portion 20 in this manner, the pneumatic tire 1 of this embodiment can be used as a studless tire, which is a winter tire that ensures driving performance on icy and snowy roads, or as an all-season tire that ensures driving performance in winter.

[0053] The sipes 70 referred to here are narrow grooves formed in the tread contact surface 3, and when the pneumatic tire 1 is mounted on a specified rim and under a specified internal pressure condition and no load is applied, the wall surfaces constituting the narrow grooves do not come into contact with each other. However, when a load is applied vertically on a flat plate and the narrow grooves are located in a portion of the contact surface formed on the flat plate, or when the land portions 20 in which the narrow grooves are formed collapse, the wall surfaces constituting the narrow grooves, or at least a portion of the portions provided on the wall surfaces, come into contact with each other due to deformation of the land portions 20. In this embodiment, the sipes 70 have a groove width of 1.0 mm or less, and a maximum depth from the tread contact surface 3 within a range of 2.0 mm to 10.0 mm.

[0054] The specified rim here refers to the "standard rim" specified by JATMA, the "design rim" specified by TRA, or the "measuring rim" specified by ETRTO. The specified internal pressure refers to the "maximum air pressure" specified by JATMA, the maximum value listed in the "tire load limits at various cold inflation pressures" specified by TRA, or the "inflation pressures" specified by ETRTO.

[0055] The sipe 70 may be a so-called three-dimensional sipe or a two-dimensional sipe. The three-dimensional sipe here refers to a sipe 70 having a curved wall surface with amplitude in the width direction of the sipe 70 in both a cross-sectional view in which the length direction of the sipe 70 is the normal direction (a cross-sectional view including the width direction and depth direction of the sipe 70) and a cross-sectional view in which the depth direction of the sipe 70 is the normal direction (a cross-sectional view including the width direction and length direction of the sipe 70). The two-dimensional sipe refers to a sipe 70 having a straight wall surface in any cross-sectional view in which the length direction of the sipe 70 is the normal direction (a cross-sectional view including the width direction and depth direction of the sipe 70).

[0056] Fig. 3 is a detailed view of part B in Fig. 2. The first second widthwise groove 42a, which is a widthwise groove 40 disposed between the first outer circumferential main groove 35a and the first inner circumferential main groove 31a, has a bent portion 43, which is a portion where the extension direction of the first second widthwise groove 42a changes, between the first outer circumferential main groove 35a and the first inner circumferential main groove 31a. The bent portion 43 of the first second widthwise groove 42a is formed to be convex in the tire circumferential direction.

[0057] That is, the first second widthwise grooves 42a are inclined in opposite directions in the tire circumferential direction with respect to the tire width direction on both sides of the bent portion 43. The bent portion 43 is a portion connecting portions of the first second widthwise grooves 42a that are inclined in different directions in the tire circumferential direction with respect to the tire width direction.

[0058] Because the first second widthwise grooves 42a are inclined in opposite directions in the tire circumferential direction with respect to the tire width direction on both sides of the bent portion 43 in the tire width direction, the multiple sipes 70 arranged in the first second land portion 22a are also inclined in opposite directions in the tire circumferential direction with respect to the tire width direction. More specifically, the multiple sipes 70 arranged in the first second widthwise groove 42a have portions that are located closer to the first inner circumferential main groove 31a than the bent portion 43 in the tire width direction and portions that are located closer to the first outer circumferential main groove 35a, which are spaced apart from each other. The multiple sipes 70 arranged in this manner are arranged in a direction that extends approximately parallel to portions of the first second widthwise groove 42a that are located at the same position in the tire width direction.

[0059] In the present embodiment, the bent portion 43 of the first second widthwise groove 42a is formed in a direction that convexly extends toward the leading side in the rotational direction of the pneumatic tire 1. For this reason, the bent portion 43 of the first second widthwise groove 42a is located on the leading side in the rotational direction of the pneumatic tire 1 relative to the end of the first second widthwise groove 42a that communicates with the circumferential main groove 30. In other words, the bent portion 43 of the first second widthwise groove 42a is located on the leading side in the rotational direction of the pneumatic tire 1 relative to both the end of the first second widthwise groove 42a that communicates with the first inner circumferential main groove 31a and the end of the first second widthwise groove 42a that communicates with the first outer circumferential main groove 35a.

[0060] Here, the first second widthwise groove 42a is connected to the first inner circumferential main groove 31a at a position on an extension of the center widthwise groove 41, and is connected to the first outer circumferential main groove 35a at a position on an extension of the first shoulder widthwise groove 45a. The first second widthwise grooves 42a are inclined in opposite directions to the tire circumferential direction with respect to the tire width direction on both sides of the bent portion 43 in the tire width direction. Therefore, the center widthwise groove 41 located on the first inner circumferential main groove 31a side of the bent portion 43 in the tire width direction and the first shoulder widthwise groove 45a located on the first outer circumferential main groove 35a side also have inclination directions in opposite directions to the tire circumferential direction with respect to the tire width direction.

[0061] The first second widthwise groove 42a has different groove widths between a portion from the bent portion 43 to the first inner circumferential main groove 31a and a portion from the bent portion 43 to the first outer circumferential main groove 35a, and the groove width is wider from the portion from the bent portion 43 to the first outer circumferential main groove 35a than from the portion from the bent portion 43 to the first inner circumferential main groove 31a. That is, the portion of the first second widthwise groove 42a from the bent portion 43 to the first inner circumferential main groove 31a is a narrow width portion 42aa with a relatively narrow groove width, and the portion of the first second widthwise groove 42a from the bent portion 43 to the first outer circumferential main groove 35a is a wide width portion 42ab with a wider groove width than the narrow width portion 42aa.

[0062] In this way, the first second widthwise groove 42a, which has different groove widths on both sides of the bend 43 in the tire width direction, has a ratio of the groove width W2 of the wide portion 42ab to the groove width W1 of the narrow portion 42aa in the range of 1.3≦W2 / W1≦2.0.

[0063] Fig. 4 is a cross-sectional view taken along line CC in Fig. 3. Fig. 5 is a cross-sectional view taken along line EE in Fig. 3. In addition, in the first second widthwise grooves 42a, the ratio of the groove depth D2 of the wide portions 42ab to the groove depth D1 of the narrow portions 42aa is within the range of 1.0≦D2 / D1≦1.7. That is, in the first second widthwise grooves 42a, the groove depth D2 of the wide portions 42ab is greater than or equal to the groove depth D1 of the narrow portions 42aa.

[0064] The first second widthwise groove 42a has different groove widths on both sides of the bent portion 43 in the tire width direction, so that the bent portion 43, which is a portion where the narrow portion 42aa and the wide portion 42ab of the first second widthwise groove 42a are connected, has a step due to the different groove width. The step at the bent portion 43 is formed on the side where the bend in the bent portion 43 is convex, i.e., on the moderate angle side of the bent portion 43. Therefore, the portion on the minor angle side of the bent portion 43 is a corner where the edge of the narrow portion 42aa and the edge of the wide portion 42ab are continuously and directly connected.

[0065] In the first second widthwise groove 42a having the bent portion 43 in this manner, the angle θ1 of the narrow portion 42aa relative to the tire circumferential direction and the angle θ2 of the wide portion 42ab relative to the tire circumferential direction are each within a range of 55° to 85°. In this case, the angle θ1 of the narrow portion 42aa relative to the tire circumferential direction is the angle θ1 of the edge of the narrow portion 42aa located on the minor angle side of the bent portion 43 relative to the tire circumferential direction, and the angle θ2 of the wide portion 42ab relative to the tire circumferential direction is the angle θ2 of the edge of the wide portion 42ab located on the minor angle side of the bent portion 43 relative to the tire circumferential direction.

[0066] In the first second widthwise groove 42a, the angle θ1 of the narrow portion 42aa relative to the tire circumferential direction and the angle θ2 of the wide portion 42ab relative to the tire circumferential direction are preferably within the range of 70° to 80°.

[0067] In addition, the bent portion 43 of the first second widthwise groove 42a is positioned at a position where the ratio of the distance L1 from the bent portion 43 in the tire width direction to the width LB of the first second land portion 22a in the tire width direction to the distance L1 from the bent portion 43 in the tire width direction to the first outer circumferential main groove 35a is within the range of 0.4≦L1 / LB≦0.6.

[0068] In this case, the width LB of the first second land portion 22a in the tire width direction is the maximum width of the first second land portion 22a in the tire width direction. Also, the distance L1 in the tire width direction from the bend 43 to the first outer circumferential main groove 35a is the distance in the tire width direction between a bend point 43a, which is a portion where the edge of the narrow portion 42aa and the edge of the wide portion 42ab are connected on the minor angle side of the bend 43, and the edge of the first outer circumferential main groove 35a on the first second land portion 22a side.

[0069] The independent grooves 50 arranged in the first second land portion 22a have a ratio of the length LG of the independent groove 50 in the tire width direction to the width LB of the first second land portion 22a in the tire width direction within the range of 0.45≦LG / LB≦0.65.

[0070] The independent groove 50 is disposed at a predetermined distance from the first inner circumferential main groove 31a and the first outer circumferential main groove 35a, which define both sides of the first second land portion 22a in the tire width direction. That is, the ratio of the distance L2 in the tire width direction from the independent groove 50 to the first inner circumferential main groove 31a to the width LB of the first second land portion 22a in the tire width direction is within a range of 0.15≦L2 / LB≦0.4. Furthermore, the ratio of the distance L3 in the tire width direction from the independent groove 50 to the first outer circumferential main groove 35a to the width LB of the first second land portion 22a in the tire width direction is within a range of 0.15≦L3 / LB≦0.4.

[0071] The independent grooves 50 are also disposed at a predetermined distance from the first second widthwise grooves 42a that define both sides of the first second land portion 22a in the tire circumferential direction, and the independent grooves 50 are disposed at positions near the centers of the two first second widthwise grooves 42a that define both sides of the first second land portion 22a in the tire circumferential direction. For this reason, the distance in the tire circumferential direction between the independent groove 50 and one of the two first second widthwise grooves 42a that define both sides of the first second land portion 22a in the tire circumferential direction is approximately the same as the distance in the tire circumferential direction between the independent groove 50 and the other first second widthwise groove 42a.

[0072] The independent grooves 50 have a polygonal shape in plan view, i.e., a shape when the independent grooves 50 are viewed in the groove depth direction of the independent grooves 50. More specifically, the independent grooves 50 have a concave polygonal shape in plan view. In this embodiment, the independent grooves 50 extend in the tire width direction and are formed in a groove shape in which the size of the interior angle of one of the multiple corners of the independent groove 50 is greater than 180°, as shown in FIG. 3. As a result, in the independent groove 50 according to this embodiment, the groove width of the portion of the independent groove 50 closer to the first inner circumferential main groove 31a is greater than the groove width of the portion of the independent groove 50 closer to the first outer circumferential main groove 35a.

[0073] The independent grooves 50 extending in the tire width direction are formed to be inclined in the tire circumferential direction with respect to the tire width direction. Specifically, the independent grooves 50 are inclined in the same direction as the narrow portion 42aa and the wide portion 42ab of the first second widthwise groove 42a, the portion of the first second widthwise groove 42a that has more portions that are positioned in the same position as the independent groove 50 in the tire width direction.

[0074] In this embodiment, the independent grooves 50 have more portions at the same position in the tire width direction in the wide portions 42ab of the first second widthwise grooves 42a than in the narrow portions 42aa. Therefore, the independent grooves 50 are inclined with respect to the tire width direction in the same direction as the wide portions 42ab of the first second widthwise grooves 42a are inclined in the tire circumferential direction with respect to the tire width direction. The independent grooves 50 that are inclined in the same direction as the wide portions 42ab of the first second widthwise grooves 42a have edges that extend approximately parallel to the edges of the wide portions 42ab.

[0075] Fig. 6 is a cross-sectional view taken along the line FF in Fig. 3. The ratio of the groove depth DG of the independent groove 50 to the groove depth D2 of the wide portion 42ab of the first second widthwise groove 42a is within the range of 0.50≦DG / D2≦0.80.

[0076] The independent groove 50 formed in the shape of a concave polygon has an area A in a plan view of 40 mm 2 ≦A≦110mm 2 In addition, it is preferable that the corner of the independent groove 50 formed in the shape of a concave polygon has an acute angle, the corner located furthest to the front in the tire rotation direction.

[0077] Furthermore, in the first second land portion 22a where the independent grooves 50 are arranged, a communicating sipe 71, which is a sipe 70 whose both ends communicate with the independent groove 50 and the first outer circumferential main groove 35a, is arranged between the independent groove 50 and the first outer circumferential main groove 35a. The communicating sipe 71 is arranged between the end of the independent groove 50 on the first outer circumferential main groove 35a side and the first outer circumferential main groove 35a, and both ends in the extension direction communicate with the independent groove 50 and the first outer circumferential main groove 35a.

[0078] In this embodiment, the communicating sipes 71 are arranged on the extension lines of the edges of the independent grooves 50 that are located on the leading side in the tire rotation direction and extend in the tire circumferential direction while being inclined, and are formed to be inclined in the same direction as the inclination direction of the edges with respect to the tire width direction. In this embodiment, the communicating sipes 71 are formed as sipes 70 with a straight shape.

[0079] When mounting the pneumatic tire 1 according to this embodiment on a vehicle, the pneumatic tire 1 is mounted on a rim wheel, filled with air, and mounted on the vehicle in an inflated state. At this time, the mounting direction and rotation direction of the pneumatic tire 1 according to this embodiment relative to the vehicle are specified, and the tire is mounted on the vehicle in the specified direction. That is, the tire is mounted on the vehicle in the direction specified by the mounting direction indicator and the rotation direction indicator attached to the sidewall portion 8. As a result, the pneumatic tire 1 is mounted on the vehicle with the side on which the independent grooves 50 are arranged positioned on the inner side of the tire equatorial plane CL in the vehicle mounting direction, the side on which the land portion inner grooves 55 are arranged positioned on the outer side of the vehicle mounting direction, and the bent portion 43 of the first second widthwise groove 42a is oriented convexly toward the leading side in the tire rotational direction.

[0080] When a vehicle equipped with pneumatic tire 1 travels, the pneumatic tire 1 rotates while the lower part of the tread contact surface 3 of the tread portion 2 comes into contact with the road surface. When a vehicle equipped with pneumatic tire 1 travels on a dry road surface, the vehicle travels by transmitting driving force and braking force to the road surface and generating turning force mainly due to the frictional force between the tread contact surface 3 and the road surface.

[0081] Furthermore, when traveling on a wet road surface, water between the tread contact surface 3 and the road surface enters grooves such as the circumferential main grooves 30 and widthwise grooves 40, and the sipes 70, and these grooves drain the water between the tread contact surface 3 and the road surface while traveling. This makes it easier for the tread contact surface 3 to make contact with the road surface, and the frictional force between the tread contact surface 3 and the road surface enables the vehicle to travel.

[0082] Furthermore, when traveling on snowy roads, the pneumatic tire 1 compacts snow on the road surface with the tread contact surface 3, and the snow on the road surface also compacts within the grooves as it enters the circumferential main grooves 30 and widthwise grooves 40. In this state, when driving or braking forces act on the pneumatic tire 1, or when a force acts in the tire width direction due to turning of the vehicle, a shear force acting on the snow in the grooves, known as snow column shear force, is generated between the pneumatic tire 1 and the snow. When traveling on snowy roads, this snow column shear force generates resistance between the pneumatic tire 1 and the road surface, allowing driving and braking forces to be transmitted to the road surface, ensuring snow traction. This allows the vehicle to travel on snowy roads.

[0083] Furthermore, when traveling on snowy or icy road surfaces, the tire also utilizes the edge effects of the circumferential main grooves 30, widthwise grooves 40, and sipes 70. That is, when traveling on snowy or icy road surfaces, the tire also utilizes the resistance caused by the edges of the circumferential main grooves 30, widthwise grooves 40, and sipes 70 catching on the snow or ice surface. Furthermore, when traveling on icy road surfaces, the sipes 70 absorb water on the surface of the icy road surface, removing the water film between the icy road surface and the tread contact surface 3, making it easier for the tread contact surface 3 to come into contact with the icy road surface. As a result, the resistance between the tread contact surface 3 and the icy road surface increases due to the adhesive friction force and edge effect between the tread contact surface 3 and the icy road surface, thereby ensuring the driving performance of a vehicle equipped with the pneumatic tire 1.

[0084] The circumferential main grooves 30, widthwise grooves 40, and sipes 70 formed in the tread portion 2 contribute to ensuring running performance when running on wet, snowy, or icy road surfaces, and therefore, in order to improve wet performance, which is running performance on wet road surfaces, for example, it is effective to increase the groove area ratio of the tread portion 2. In other words, if the groove area ratio, which is the ratio of the area of ​​grooves such as the circumferential main grooves 30 and widthwise grooves 40 in the contact patch, is increased, water on the road surface will more easily enter the grooves when running on a wet road surface, thereby improving the drainage of water between the tread contact surface 3 and the road surface and improving wet performance.

[0085] Increasing the groove area ratio is also effective in improving snow performance, which is driving performance on snowy roads. In other words, when the groove area ratio is increased, the amount of snow that can be trapped in the circumferential main grooves 30 and the widthwise grooves 40 when driving on snowy roads can be increased, thereby increasing the snow column shear force acting on the snow trapped in the grooves. This improves snow traction when driving on snowy roads, and improves snow performance.

[0086] However, when the groove area ratio is increased, the volume of the land portion 20 is relatively reduced, which reduces the rigidity of the land portion 20. When the rigidity of the land portion 20 is reduced, the land portion 20 becomes more susceptible to wear, which may result in a reduction in wear resistance.

[0087] Therefore, in order to suppress the deterioration of wear resistance, it is preferable to reduce the groove area ratio to ensure the rigidity of the land portion 20. Furthermore, when the groove area ratio is reduced, the actual contact area can be relatively increased, and the increased actual contact area can improve adhesion friction and ice performance, which is the driving performance on icy roads. However, when the groove area ratio is reduced, the amount of water and snow on the road surface that can enter the circumferential main grooves 30 and widthwise grooves 40 is reduced, which may easily deteriorate wet performance and snow performance.

[0088] In contrast, in the pneumatic tire 1 according to this embodiment, the first second widthwise grooves 42a have the bent portions 43, so it is possible to increase the edge amount by ensuring the length of the first second widthwise grooves 42a while suppressing an increase in the groove area ratio. As a result, the increased edge amount ensures driving performance on snowy and icy roads, while suppressing a decrease in rigidity of the land portions 20, thereby improving wear resistance.

[0089] Furthermore, the first second widthwise groove 42a is connected to the first outer circumferential main groove 35a and the first inner circumferential main groove 31a at positions on the extension lines of the center widthwise groove 41 and the first shoulder widthwise groove 45a. Therefore, these grooves improve drainage and snow column shear force, thereby ensuring driving performance on wet and snowy roads.

[0090] Furthermore, because the first second land portion 22a has the independent grooves 50 arranged therein, it is possible to ensure driving performance on snowy and icy road surfaces by increasing the amount of edges provided by the independent grooves 50. Furthermore, because both ends of the independent grooves 50 in the tire width direction terminate within the first second land portion 22a, it is possible to ensure driving performance on icy road surfaces by ensuring adhesive frictional force, and it is possible to improve wear resistance by ensuring the rigidity of the first second land portion 22a.

[0091] Furthermore, since the first second widthwise grooves 42a and the independent grooves 50 are arranged alternately in the tire circumferential direction, the running performance due to the first second widthwise grooves 42a and the running performance due to the independent grooves 50 are ensured uniformly in the tire circumferential direction, while the rigidity of the land portions 20 is made uniform in the tire circumferential direction, suppressing bias in the rigidity of the land portions 20, thereby improving wear resistance. As a result, by optimizing the pattern configuration, it is possible to improve wear resistance while ensuring snow and ice performance and wet performance.

[0092] Furthermore, the angle θ1 of the narrow portion 42aa relative to the tire circumferential direction of the first second widthwise groove 42a and the angle θ2 of the wide portion 42ab relative to the tire circumferential direction of the first second widthwise groove 42a are both within the range of 55° to 85°, so that the edge amount of the first second widthwise groove 42a can be increased while suppressing a decrease in the rigidity of the first second land portion 22a. In other words, if the angle θ1 of the narrow portion 42aa or the angle θ2 of the wide portion 42ab of the first second widthwise groove 42a is less than 55°, the angle θ1 of the narrow portion 42aa or the angle θ2 of the wide portion 42ab is too small, which may result in the angle of the bent portion 43 being too small. In this case, the rigidity of the first second land portion 22a defined by the first second widthwise groove 42a is likely to decrease, which may make it difficult to improve wear resistance. Furthermore, if the angle θ1 of the narrow portion 42aa of the first second widthwise groove 42a or the angle θ2 of the wide portion 42ab is greater than 85°, the angle θ1 of the narrow portion 42aa or the angle θ2 of the wide portion 42ab may be too large, which may result in an excessively large angle of the bent portion 43. In this case, even if the bent portion 43 is provided in the first second widthwise groove 42a, it may be difficult to ensure the length of the first second widthwise groove 42a, making it difficult to increase the amount of edge, and thus may make it difficult to ensure driving performance on snowy or icy roads.

[0093] In contrast, when the angle θ1 of the narrow portion 42aa of the first second widthwise groove 42a and the angle θ2 of the wide portion 42ab of the first second widthwise groove 42a are within the range of 55° to 85°, the length of the first second widthwise groove 42a can be secured by the bent portion 43, and the edge amount can be increased while suppressing a decrease in rigidity of the first second land portion 22a. As a result, it is possible to improve wear resistance while more reliably securing ice and snow performance.

[0094] Furthermore, the bent portion 43 of the first second widthwise groove 42a has a ratio of the distance L1 in the tire width direction from the bent portion 43 to the first outer circumferential main groove 35a to the width LB of the first second land portion 22a in the tire width direction within a range of 0.4≦L1 / LB≦0.6, so that the edge effect of the first second widthwise groove 42a can be appropriately exhibited. In other words, if the ratio of the distance L1 from the bent portion 43 to the first outer circumferential main groove 35a to the width LB of the first second land portion 22a is L1 / LB<0.4 or L1 / LB>0.6, there is a risk that the difference in length between the narrow portion 42aa and the wide portion 42ab of the first second widthwise groove 42a will become too large. In this case, the difference between the edge amount of the narrow portion 42aa and the edge amount of the wide portion 42ab becomes large, which may cause a bias in the direction in which the edge effect of the first second widthwise groove 42a can be exerted, making it difficult to ensure appropriate driving performance on snowy or icy roads.

[0095] In contrast, when the ratio of the distance L1 from the bend 43 to the first outer circumferential main groove 35a to the width LB of the first second land portion 22a is within the range of 0.4≦L1 / LB≦0.6, the edge length of the narrow portion 42aa and the edge length of the wide portion 42ab can be made nearly equal. This allows the edge effect of the first second widthwise groove 42a to be exerted in a wider direction. As a result, ice and snow performance can be more reliably ensured.

[0096] Furthermore, since the ratio of the groove width W2 of the wide portions 42ab to the groove width W1 of the narrow portions 42aa of the first second widthwise grooves 42a is within the range of 1.3≦W2 / W1≦2.0, the groove width W2 of the wide portions 42ab can be ensured to be an appropriate groove width while ensuring the rigidity of the first second land portion 22a. In other words, if the ratio of the groove width W2 of the wide portions 42ab to the groove width W1 of the narrow portions 42aa of the first second widthwise grooves 42a is W2 / W1<1.3, the groove width W2 of the wide portions 42ab is too narrow, and it may be difficult to effectively ensure driving performance on snowy roads even if the first second widthwise grooves 42a are provided. Furthermore, if the ratio of the groove width W2 of the wide portions 42ab to the groove width W1 of the narrow portions 42aa of the first second widthwise grooves 42a is W2 / W1 > 2.0, the groove width W2 of the wide portions 42ab is too wide, which may reduce the rigidity of the first second land portion 22a. In this case, the first second land portion 22a may be more susceptible to wear, making it difficult to improve wear resistance.

[0097] In contrast, when the ratio of the groove width W2 of the wide portions 42ab to the groove width W1 of the narrow portions 42aa of the first second widthwise grooves 42a is within the range of 1.3≦W2 / W1≦2.0, the groove width W2 of the wide portions 42ab can be set to an appropriate groove width while ensuring the rigidity of the first second land portion 22a. This makes it easier for snow on the road surface to enter the first second widthwise grooves 42a, thereby ensuring an appropriate snow column shear force in the first second widthwise grooves 42a. As a result, it is possible to more reliably ensure on-snow performance while improving wear resistance.

[0098] Furthermore, since the ratio of the groove depth D2 of the wide portions 42ab to the groove depth D1 of the narrow portions 42aa of the first second widthwise grooves 42a is within the range of 1.0≦D2 / D1≦1.7, the groove depth D2 of the wide portions 42ab can be set to an appropriate depth while ensuring the rigidity of the first second land portion 22a. In other words, if the ratio of the groove depth D2 of the wide portions 42ab to the groove depth D1 of the narrow portions 42aa of the first second widthwise grooves 42a is D2 / D1<1.0, the groove depth D2 of the wide portions 42ab is too shallow, which may make it difficult to effectively ensure wet performance by the first second widthwise grooves 42a. Furthermore, if the ratio of the groove depth D2 of the wide portions 42ab to the groove depth D1 of the narrow portions 42aa of the first second widthwise grooves 42a is D2 / D1 > 1.7, the groove depth D2 of the wide portions 42ab is too deep, which may reduce the rigidity of the first second land portion 22a. In this case, the first second land portion 22a may be more susceptible to wear, making it difficult to improve wear resistance.

[0099] In contrast, when the ratio of the groove depth D2 of the wide portions 42ab to the groove depth D1 of the narrow portions 42aa of the first second widthwise grooves 42a is within the range of 1.0≦D2 / D1≦1.7, the groove depth D2 of the wide portions 42ab can be set to an appropriate depth while ensuring the rigidity of the first second land portion 22a. This makes it easier for water on the road surface to enter the first second widthwise grooves 42a, ensuring appropriate drainage in the first second widthwise grooves 42a. As a result, wet performance can be more reliably ensured while wear resistance can be improved.

[0100] Furthermore, the bent portion 43 of the first second widthwise groove 42a is located on the leading side in the tire rotation direction relative to the ends of the first second widthwise groove 42a that communicate with the first inner circumferential main groove 31a and the first outer circumferential main groove 35a, which makes it easier for water that has entered the first second widthwise groove 42a to be drained toward the first inner circumferential main groove 31a and the first outer circumferential main groove 35a, thereby more reliably improving wet performance.

[0101] Furthermore, the ratio of the length LG of the independent groove 50 in the tire width direction to the width LB of the first second land portion 22a in the tire width direction is within the range of 0.45≦LG / LB≦0.65, so the length LG of the independent groove 50 can be set to an appropriate size while ensuring the rigidity of the first second land portion 22a. In other words, if the ratio of the length LG of the independent groove 50 in the tire width direction to the width LB of the first second land portion 22a in the tire width direction is LG / LB<0.45, the length LG of the independent groove 50 is too small, making it difficult to ensure the edge effect of the independent groove 50 and potentially making it difficult to effectively ensure driving performance on snowy or icy roads. If the ratio of the length LG of the independent groove 50 in the tire width direction to the width LB of the first second land portion 22a in the tire width direction is LG / LB>0.65, the length LG of the independent groove 50 is too large, making it possible for the rigidity of the first second land portion 22a to be easily reduced. In this case, the first second land portion 22a may be more susceptible to wear, making it difficult to improve the wear resistance.

[0102] In contrast, when the ratio of the length LG of the independent groove 50 in the tire width direction to the width LB of the first second land portion 22a in the tire width direction is within the range of 0.45≦LG / LB≦0.65, the length LG of the independent groove 50 can be set to an appropriate size while ensuring the rigidity of the first second land portion 22a, and the edge effect of the independent groove 50 can be ensured. As a result, it is possible to more reliably ensure snow and ice performance while improving wear resistance.

[0103] In addition, the independent groove 50 has an area A of 40 mm 2 ≦A≦110mm 2 Since the area A of the independent groove 50 is within the range of 40 mm, it is possible to ensure the rigidity of the first second land portion 22a while making the area A of the independent groove 50 an appropriate size. 2 If the area A of the independent grooves 50 is less than 110 mm, the area A of the independent grooves 50 is too small, making it difficult to ensure the edge effect of the independent grooves 50 and making it difficult to effectively ensure driving performance on snowy or icy road surfaces. 2If the area A is larger than 1 / 2, the area A of the independent groove 50 becomes too large, which may reduce the rigidity of the first second land portion 22a. In this case, the first second land portion 22a becomes more susceptible to wear, which may make it difficult to improve the wear resistance.

[0104] In contrast, the area A of the independent groove 50 is 40 mm 2 ≦A≦110mm 2 Within this range, the area A of the independent grooves 50 can be made an appropriate size while ensuring the rigidity of the first second land portion 22a, and the edge effect of the independent grooves 50 can be ensured. As a result, it is possible to improve the abrasion resistance while more reliably ensuring the ice and snow performance.

[0105] Furthermore, because the independent grooves 50 have a concave polygonal shape in plan view, it is possible to effectively increase the amount of edge of the independent grooves 50 relative to the area of ​​the independent grooves 50, thereby enhancing the edge effect of the independent grooves 50. As a result, it is possible to more reliably improve ice and snow performance.

[0106] Furthermore, the ratio of the distance L2 from the independent groove 50 to the first inner circumferential main groove 31a to the width LB of the first second land portion 22a is within the range of 0.15≦L2 / LB≦0.4, and the ratio of the distance L3 from the independent groove 50 to the first outer circumferential main groove 35a to the width LB of the first second land portion 22a is within the range of 0.15≦L3 / LB≦0.4, so that the rigidity of the portions on both sides of the independent groove 50 in the first second land portion 22a can be appropriately ensured.

[0107] That is, when the ratio of the width LB of the first second land portion 22a to the distance L2 between the independent groove 50 and the first inner circumferential main groove 31a is L2 / LB<0.15, or when the ratio of the width LB of the first second land portion 22a to the distance L3 between the independent groove 50 and the first outer circumferential main groove 35a is L3 / LB>0.4, the distance between the independent groove 50 and the first inner circumferential main groove 31a may become too small. In this case, it may be difficult to ensure the rigidity of the portion of the first second land portion 22a between the independent groove 50 and the first inner circumferential main groove 31a, and therefore it may be difficult to ensure uneven wear resistance. Furthermore, if the ratio of the width LB of the first second land portion 22a to the distance L2 between the independent groove 50 and the first inner circumferential main groove 31a is L2 / LB>0.4, or if the ratio of the width LB of the first second land portion 22a to the distance L3 between the independent groove 50 and the first outer circumferential main groove 35a is L3 / LB<0.15, the distance between the independent groove 50 and the first outer circumferential main groove 35a may become too small. In this case, it may be difficult to ensure the rigidity of the portion of the first second land portion 22a between the independent groove 50 and the first outer circumferential main groove 35a, and therefore it may be difficult to ensure uneven wear resistance.

[0108] In contrast, when the ratio of the width LB of the first second land portion 22a to the distance L2 between the independent groove 50 and the first inner circumferential main groove 31a is within the range of 0.15≦L2 / LB≦0.4 and the ratio of the width LB of the first second land portion 22a to the distance L3 between the independent groove 50 and the first outer circumferential main groove 35a is within the range of 0.15≦L3 / LB≦0.4, the rigidity of the portions of the first second land portion 22a on both sides of the independent groove 50 in the tire width direction can be appropriately ensured. As a result, wear resistance can be improved more reliably.

[0109] Furthermore, since the first second land portion 22a has a communicating sipe 71 disposed between the independent groove 50 and the first outer circumferential main groove 35a and communicating at both ends with the independent groove 50 and the first outer circumferential main groove 35a, water on the road surface that has entered the independent groove 50 when driving on a wet road can be channeled into the first outer circumferential main groove 35a. As a result, drainage can be improved, and wet performance can be improved.

[0110] Furthermore, the independent grooves 50 are inclined in the same direction in the tire circumferential direction relative to the tire width direction as the narrow portions 42aa and wide portions 42ab of the first second widthwise grooves 42a, which are located on the side where the majority of the portions are aligned with the independent grooves 50 in the tire width direction. This reduces the change in the distance between the independent grooves 50 and the first second widthwise grooves 42a in the first second land portion 22a, preventing the occurrence of a portion where the distance between the independent grooves 50 and the first second widthwise grooves 42a is extremely small. This prevents the occurrence of a portion where the rigidity is low in the first second land portion 22a, ensuring appropriate rigidity in the portion of the first second land portion 22a between the independent grooves 50 and the first second widthwise grooves 42a. As a result, wear resistance can be more reliably improved.

[0111] Furthermore, since the land portion 20 is provided with a plurality of sipes 70 extending in the tire width direction, the amount of edge can be increased by the plurality of sipes 70, and the increased edge effect can improve driving performance on snowy and icy road surfaces. As a result, snow and ice performance can be improved more reliably.

[0112] Furthermore, the sipes 70 arranged in the land portions 20 are inclined in the same direction in the tire circumferential direction relative to the tire width direction as the widthwise grooves 40 that are located at the same positions in the tire width direction. This makes it possible to suppress changes in the distance between the sipes 70 and the widthwise grooves 40 in the land portions 20 and between adjacent sipes 70, thereby preventing the occurrence of portions where the distance between the sipes 70 and the widthwise grooves 40 or between adjacent sipes 70 becomes extremely small. This prevents the occurrence of portions where the rigidity is low in the land portions 20, and ensures appropriate rigidity in the portions between the sipes 70 and the widthwise grooves 40 and between adjacent sipes 70 in the land portions 20. As a result, wear resistance can be improved more reliably.

[0113] [Variations] In the above-described embodiment, the independent grooves 50 arranged in the first second land portion 22a have a groove width that is larger in the portion closer to the first inner circumferential main groove 31a than in the portion closer to the first outer circumferential main groove 35a. However, the independent grooves 50 may be formed in other forms.

[0114] FIG. 7 is an explanatory diagram showing a modified example of the pneumatic tire 1 according to the embodiment, in which the groove width of the independent groove 50 is larger near the first outer circumferential main groove 35a than near the first inner circumferential main groove 31a. FIG. 8 is an explanatory diagram showing a modified example of the pneumatic tire 1 according to the embodiment, in which the independent groove 50 has a protruding portion in the groove width direction. For example, as shown in FIG. 7, the independent groove 50 disposed in the first second land portion 22a may have a larger groove width at a portion of the independent groove 50 near the first outer circumferential main groove 35a than at a portion of the independent groove 50 near the first inner circumferential main groove 31a. Furthermore, as shown in FIG. 8, the independent groove 50 may have a protruding portion protruding in the groove width direction. The independent groove 50 may be formed in a concave polygonal shape, such as the shape according to the embodiment or the shapes shown in FIGS. 7 and 8, to increase the edge amount, thereby improving snow and ice performance.

[0115] Furthermore, in the above-described embodiment, two circumferential main grooves 30 are arranged on each side of the tire equatorial plane CL in the tire width direction, but the number of circumferential main grooves 30 may be other than this. For example, three or more circumferential main grooves 30 may be arranged on one side of the tire equatorial plane CL in the tire width direction. Regardless of the number of circumferential main grooves 30, the tread pattern of the pneumatic tire 1 only needs to have a second width direction groove 42 having a bent portion 43 and an independent groove 50 arranged between an outer circumferential main groove 35 located outermost in the tire width direction and an inner circumferential main groove 31 adjacent to the outer circumferential main groove 35.

[0116] In the above-described embodiment, the tread pattern is different between the inner side and the outer side in the vehicle mounting direction relative to the tire equatorial plane CL, but the tread pattern may be formed in the same pattern on both sides of the tire equatorial plane CL. For example, the tread pattern on the inner side in the vehicle mounting direction in the embodiment may be formed on the outer side in the vehicle mounting direction in line symmetry with respect to the tire equatorial plane CL. That is, the inner circumferential main groove 31 having the bent portion 43 and the independent grooves 50 may also be arranged on the outer side in the vehicle mounting direction.

[0117] Furthermore, in the above-described embodiment, the pneumatic tire 1 is described using a tire in which the vehicle mounting direction and the tire rotation direction are specified, but the pneumatic tire 1 does not need to have a specified vehicle mounting direction or tire rotation direction. The above-described embodiments and variations may be combined as appropriate. Furthermore, in the above-described embodiment, the pneumatic tire 1 is described using an example of a tire according to the present invention, but the tire according to the present invention may be something other than the pneumatic tire 1. The tire according to the present invention may be, for example, a so-called airless tire that can be used without being filled with gas.

[0118] [Example] 9A and 9B are tables showing the results of performance evaluation tests of pneumatic tires. Performance evaluation tests conducted on the conventional pneumatic tire, the pneumatic tire 1 according to the present invention, and a comparative pneumatic tire compared to the pneumatic tire 1 according to the present invention will be described below. The performance evaluation tests were conducted on ice performance, snow performance, wet performance, and wear resistance.

[0119] The performance evaluation test was carried out by mounting a pneumatic tire 1 having a tire nominal size of 195 / 65R15 91Q as specified by JATMA on a JATMA standard rim wheel having a rim size of 15 x 6.5J, mounting the test tire on a front-wheel drive evaluation vehicle with an engine displacement of 1800cc, adjusting the air pressure to 240kPa, and running the evaluation vehicle.

[0120] The evaluation method for each test item was as follows: for ice performance, a braking test was conducted on an icy test course using an evaluation vehicle fitted with test tires, and the reciprocal of the braking distance was expressed as an index, with the conventional example (described below) set at 100. The higher the index, the shorter the braking distance on icy roads, indicating better ice performance.

[0121] Snow performance was evaluated by conducting braking tests on a test course on snowy roads using an evaluation vehicle fitted with the test tires, and expressing the reciprocal of the braking distance as an index, with the conventional example (described below) set at 100. The higher the index, the shorter the braking distance on snowy roads, indicating better snow performance.

[0122] Additionally, wet performance was evaluated by conducting a braking test on an asphalt test course where 1.0 mm of water was sprayed on an evaluation vehicle fitted with the test tire, and expressing the reciprocal of the braking distance as an index, with the conventional example (described below) set to 100. The higher the index, the shorter the braking distance on a wet road surface, indicating superior wet performance. Note that an index of 98 or higher is considered to maintain a similar level to the conventional example, and to ensure wet performance that compares favorably with the conventional example.

[0123] Wear resistance was evaluated by measuring the groove depth after a 10,000 km road test was conducted by a test driver on an evaluation vehicle fitted with the test tires. Wear resistance was evaluated by expressing the measured groove depth as an index, with the conventional example (described below) being set at 100, and the higher the index, the better the wear resistance.

[0124] The performance evaluation test was conducted on 23 types of pneumatic tires, including a conventional pneumatic tire which is an example of a conventional pneumatic tire, Examples 1 to 21 which are pneumatic tire 1 according to the present invention, and a comparative example which is a pneumatic tire compared with pneumatic tire 1 according to the present invention. Of these, in the conventional example, the second widthwise grooves do not have bent portions, and no independent grooves are arranged in the second land portion. In addition, in the comparative example, the second widthwise grooves have bent portions, but no independent grooves are arranged in the second land portion.

[0125] In contrast, in Examples 1 to 21, which are examples of the pneumatic tire 1 according to the present invention, the second widthwise grooves 42 all have bent portions 43, and independent grooves 50 are arranged in the second land portion 22. Furthermore, the pneumatic tires 1 according to Examples 1 to 21 are different in the angle of the portion from the bent portion 43 of the second widthwise groove 42 to the tire circumferential direction of the circumferential main groove 30, the ratio L1 / LB of the distance L1 from the bent portion 43 to the outer circumferential main groove 35 to the width LB of the second land portion 22, the ratio W2 / W1 of the groove width W2 of the wide portion 42ab to the groove width W1 of the narrow portion 42aa of the second widthwise groove 42, the ratio D2 / D1 of the groove depth D2 of the wide portion 42ab to the groove depth D1 of the narrow portion 42aa of the second widthwise groove 42, the ratio LG / LB of the length LG of the independent groove 50 to the width LB of the second land portion 22, and the area of ​​the independent groove 50.

[0126] 9A and 9B, performance evaluation tests were conducted using these pneumatic tires 1. As a result, it was found that the pneumatic tires 1 according to Examples 1 to 21 could improve ice performance, snow performance, and wear resistance while minimizing the deterioration of wet performance compared to the conventional tire. In other words, the pneumatic tires 1 according to Examples 1 to 21 could improve wear resistance while ensuring snow and ice performance and wet performance.

[0127] The present disclosure encompasses the following inventions. Invention[1] A plurality of circumferential main grooves disposed in the tread portion and extending in the tire circumferential direction; A plurality of widthwise grooves disposed in the tread portion and extending in the tire width direction; a land portion defined by the circumferential main groove and the widthwise groove; Equipped with The plurality of circumferential main grooves are an outer circumferential main groove disposed outermost in the tire width direction; an inner circumferential main groove adjacent to the outer circumferential main groove at a position inside the outer circumferential main groove in the tire width direction; and The plurality of widthwise grooves are a shoulder width direction groove disposed on the outer side of the outer circumferential main groove in the tire width direction and communicating with the outer circumferential main groove; a center width direction groove disposed on the inner side of the inner circumferential main groove in the tire width direction, one end of which communicates with the inner circumferential main groove and the other end of which terminates within the land portion; a second widthwise groove disposed between the outer circumferential main groove and the inner circumferential main groove, the second widthwise groove having both ends in the tire width direction that communicate with the outer circumferential main groove and the inner circumferential main groove at positions on an extension line of the shoulder widthwise groove and an extension line of the center widthwise groove, the second widthwise groove having a bent portion whose extending direction changes between the outer circumferential main groove and the inner circumferential main groove; and Among the plurality of land portions, a second land portion is a land portion that is partitioned on both sides in the tire width direction by the outer circumferential main groove and the inner circumferential main groove, and an independent groove that extends in the tire width direction and has both ends terminating within the second land portion is arranged in the second land portion, The tire, characterized in that the second widthwise grooves and the independent grooves are alternately arranged in the tire circumferential direction between the outer circumferential main groove and the inner circumferential main groove. Invention[2] The tire according to invention [1], wherein the angle θ1 of the second widthwise groove relative to the tire circumferential direction at the portion from the bend to the inner circumferential main groove side and the angle θ2 of the second widthwise groove relative to the tire circumferential direction at the portion from the bend to the outer circumferential main groove side are both within the range of 55° or more and 85° or less. Invention[3] The tire according to invention [1] or invention [2], wherein the ratio of the distance L1 from the bent portion in the tire width direction to the outer circumferential main groove to the width LB of the second land portion in the tire width direction is within the range of 0.4≦L1 / LB≦0.6. Invention[4] The tire according to any one of the inventions [1] to [3], wherein the ratio of the groove width W2 of the second widthwise groove from the bend portion to the groove width W1 of the second widthwise groove from the bend portion to the groove width W2 of the second widthwise groove from the bend portion to the groove width W1 of the second widthwise groove from the bend portion to the groove width W2 of the second widthwise groove is within the range of 1.3≦W2 / W1≦2.0. Invention[5] The tire according to any one of Inventions [1] to [4], wherein the ratio of the groove depth D2 of the second widthwise groove from the bend portion to the groove depth D1 of the second widthwise groove from the bend portion to the groove depth D2 of the second widthwise groove from the bend portion to the groove depth D1 of the second widthwise groove from the bend portion to the groove depth D2 of the second widthwise groove is within the range of 1.0≦D2 / D1≦1.7. Invention[6] The tire is mounted on the vehicle so as to rotate in a specified direction about a rotation axis when the vehicle moves forward, The tire according to any one of Inventions [1] to [5], wherein the second widthwise groove has the bent portion located on the leading side in the rotational direction relative to the end of the second widthwise groove that communicates with the circumferential main groove. Invention[7] The tire according to any one of the inventions [1] to [6], wherein the ratio of the length LG of the independent groove in the tire width direction to the width LB of the second land portion in the tire width direction is within the range of 0.45≦LG / LB≦0.65. Invention[8] The independent grooves have an area A of 40 mm 2 ≦A≦110mm 2 A tire according to any one of inventions [1] to [7] within the scope of the present invention. Invention[9] The tire according to any one of the inventions [1] to [8], wherein the independent groove has a concave polygonal shape in a plan view. Invention

[10] The independent grooves are a ratio of a distance L2 in the tire width direction from the independent groove to the inner circumferential main groove to a width LB in the tire width direction of the second land portion is within a range of 0.15≦L2 / LB≦0.4, a ratio of a distance L3 in the tire width direction from the independent groove to the outer circumferential main groove to a width LB in the tire width direction of the second land portion is within a range of 0.15≦L3 / LB≦0.4; A tire according to any one of Inventions [1] to [9]. Invention

[11] A tire according to any one of inventions [1] to

[10] , wherein a sipe is arranged in the second land portion between the independent groove and the outer circumferential main groove, and both ends of the sipe are connected to the independent groove and the outer circumferential main groove. Invention

[12] The tire according to any one of inventions [1] to

[11] , wherein the independent groove is inclined in the same direction as the tire circumferential direction with respect to the tire width direction, at a portion of the second widthwise groove from the bend portion to the inner circumferential main groove side and at a portion from the bend portion to the outer circumferential main groove side, at a portion where the position in the tire width direction is the same as that of the independent groove. Invention

[13] The tire according to any one of Inventions [1] to

[12] , wherein the tire is a winter tire or an all-season tire in which a plurality of sipes extending in the tire width direction are arranged in the land portion. Invention

[14] The tire according to the invention

[13] , wherein the sipes are inclined in the same direction as the widthwise grooves, which are positioned at the same position in the tire width direction, in the tire circumferential direction relative to the tire width direction. [Explanation of symbols]

[0128] 1 pneumatic tire 2 Tread section 3 Tread contact surface 4 Tread rubber 5 Shoulder section 8 Sidewall 10 Bead section 11 Bead core 12 Bead filler 13 Carcass layer 14 Belt Layer 16 Inner liner 17 Rim cushion rubber 18 Tire inner surface 20 Land 21 Center Land Section 22 Second Land Club 22a 1st Second Land Section 22b 2nd Land Section 23 Shoulder land area 23a First Shoulder Land Section 23b Second shoulder land section 30 Circumferential main groove 31 Inner circumferential main groove 31a 1st inner circumferential main groove 31b 2nd inner circumferential main groove 35 Outer circumferential main groove 35a 1st outer circumferential main groove 35b 2nd outer circumferential main groove 40 Width groove 41 Center width direction groove 42 Second widthwise groove 42a First second widthwise groove 42b Second widthwise groove 43 Bend 45 Shoulder width groove 50 independent groove 55 Inland ditch 60 Shoulder narrow groove 70 sipes 71 Interconnected sipes

Claims

1. A plurality of circumferential main grooves disposed in the tread portion and extending in the tire circumferential direction; A plurality of widthwise grooves disposed in the tread portion and extending in the tire width direction; a land portion defined by the circumferential main groove and the widthwise groove; Equipped with The plurality of circumferential main grooves are an outer circumferential main groove disposed outermost in the tire width direction; an inner circumferential main groove adjacent to the outer circumferential main groove at a position inside the outer circumferential main groove in the tire width direction; and The plurality of widthwise grooves are a shoulder width direction groove disposed on the outer side of the outer circumferential main groove in the tire width direction and communicating with the outer circumferential main groove; a center width direction groove disposed on the inner side of the inner circumferential main groove in the tire width direction, one end of which communicates with the inner circumferential main groove and the other end of which terminates within the land portion; a second widthwise groove disposed between the outer circumferential main groove and the inner circumferential main groove, the second widthwise groove having both ends in the tire width direction that communicate with the outer circumferential main groove and the inner circumferential main groove at positions on an extension line of the shoulder widthwise groove and an extension line of the center widthwise groove, the second widthwise groove having a bent portion whose extending direction changes between the outer circumferential main groove and the inner circumferential main groove; and Among the plurality of land portions, a second land portion is a land portion that is partitioned on both sides in the tire width direction by the outer circumferential main groove and the inner circumferential main groove, and an independent groove that extends in the tire width direction and has both ends terminating within the second land portion is arranged in the second land portion, The tire, characterized in that the second widthwise grooves and the independent grooves are alternately arranged in the tire circumferential direction between the outer circumferential main groove and the inner circumferential main groove.

2. 2. The tire according to claim 1, wherein an angle θ1 of the second widthwise groove relative to the tire circumferential direction at a portion from the bend portion to the inner circumferential main groove side and an angle θ2 of the second widthwise groove relative to the tire circumferential direction at a portion from the bend portion to the outer circumferential main groove side are each within a range of 55° or more and 85° or less.

3. 2. The tire according to claim 1, wherein a ratio of a distance L1 from the bent portion in the tire width direction to a width LB of the second land portion in the tire width direction to the outer circumferential main groove is within a range of 0.4≦L1 / LB≦0.

6.

4. 2. The tire according to claim 1, wherein the second widthwise groove has a groove width W2 of a portion from the bend portion to the outer circumferential main groove side relative to a groove width W1 of a portion from the bend portion to the inner circumferential main groove side, the ratio of which is within a range of 1.3≦W2 / W1≦2.

0.

5. 2. The tire according to claim 1, wherein a ratio of a groove depth D2 from the bend portion to the outer circumferential main groove side to a groove depth D1 from the bend portion to the inner circumferential main groove side of the second widthwise groove is within a range of 1.0≦D2 / D1≦1.

7.

6. The tire is mounted on the vehicle so as to rotate in a specified direction about a rotation axis when the vehicle moves forward, The tire according to claim 1 , wherein the bent portion of the second widthwise groove is located on a leading side in the rotational direction with respect to an end of the second widthwise groove that communicates with the circumferential main groove.

7. 2. The tire according to claim 1, wherein a ratio of a length LG of the independent groove in the tire width direction to a width LB of the second land portion in the tire width direction is within a range of 0.45≦LG / LB≦0.

65.

8. The independent grooves have an area A of 40 mm ２ ≦A≦110mm ２ 2. The tire of claim 1, wherein the range is:

9. The tire according to claim 1 , wherein the independent groove has a concave polygonal shape in a plan view.

10. The independent grooves are a ratio of a distance L2 in the tire width direction from the independent groove to the inner circumferential main groove to a width LB of the second land portion in the tire width direction is within a range of 0.15≦L2 / LB≦0.4, a ratio of a distance L3 in the tire width direction from the independent groove to the outer circumferential main groove to a width LB in the tire width direction of the second land portion is within a range of 0.15≦L3 / LB≦0.4; 2. The tire of claim 1.

11. The tire according to claim 1 , wherein a sipe is disposed in the second land portion between the independent groove and the outer circumferential main groove, the sipe having both ends communicating with the independent groove and the outer circumferential main groove.

12. 2. The tire according to claim 1, wherein the independent grooves are inclined in the same direction in the tire circumferential direction with respect to the tire width direction as a portion of the second widthwise groove from the bent portion to the inner circumferential main groove side and a portion of the second widthwise groove from the bent portion to the outer circumferential main groove side, the portion having more portions that are positioned at the same position in the tire width direction as the independent groove.

13. The tire according to claim 1 , wherein the tire is a winter tire or an all-season tire, and a plurality of sipes extending in the tire width direction are arranged in the land portion.

14. The tire according to claim 13 , wherein the sipes are inclined in the same direction in the tire circumferential direction with respect to the tire width direction as the widthwise grooves that are positioned at the same positions in the tire width direction.

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