tire

Abstract

To improve abrasion resistance while ensuring snow and ice performance. The maximum dimension L3 of the inner center land portion 21B in the tire width direction and the maximum dimension L4 of the inner middle land portion 22B in the tire width direction are L3

Description

[Technical Field]

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

[0002] For example, the tire described in Patent Document 1 has a tread pattern provided with lug grooves that penetrate the land portions, lug grooves that terminate within the land portions, and sipes that are provided in the land portions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-089763 Summary of the Invention [Problem to be solved by the invention]

[0004] Traditionally, studless tires have placed importance on ice performance, but there is also a demand for improved performance on snow. Generally, improving ice performance 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. Furthermore, there is a demand for improved snow performance and wear resistance, even for wide, low-profile tires.

[0005] An object of the present invention is to provide a tire that can improve wear resistance while ensuring snow and ice performance by optimizing the pattern configuration. [Means for solving the problem]

[0006] In order to achieve the above object, a tire according to one aspect of the present invention includes a center circumferential groove formed linearly along the tire circumferential direction and arranged closest to the tire equatorial plane, one middle circumferential groove and the other middle circumferential groove formed linearly along the tire circumferential direction and arranged on either side of the center circumferential groove, one shoulder circumferential groove and the other shoulder circumferential groove formed linearly along the tire circumferential direction and defined on the tire width direction outer side of each of the middle circumferential grooves, one center land portion defined between the center circumferential groove and the one middle circumferential groove, the other center land portion defined between the center circumferential groove and the other middle circumferential groove, one middle land portion defined between the one middle circumferential groove and the one shoulder circumferential groove, the other middle land portion defined between the other middle circumferential groove and the other shoulder circumferential groove, one shoulder land portion defined on the tire width direction outer side of the one shoulder circumferential groove, and a shoulder land portion defined on the tire width direction outer side of the other shoulder circumferential groove. one middle lug groove, which is arranged in a line in the tire circumferential direction in the one middle land portion, and has a base end extending along the tire width direction and communicating with the one shoulder circumferential groove and a tip end terminating inside the one middle land portion, and one center lug groove, which is arranged in a line in the tire circumferential direction in the one center land portion, and has a base end extending along the tire width direction and communicating with the one middle circumferential groove and a tip end terminating inside the one center land portion, and one center lug groove, which is arranged in a line in the tire circumferential direction in the one center land portion, and a plurality of other first center lug grooves arranged side by side in the tire circumferential direction, each having a base end extending along the tire width direction that is connected to the center circumferential groove and a tip end that penetrates the other center land portion and is connected to the other middle circumferential groove; and a plurality of other second center lug grooves arranged side by side in the tire circumferential direction in the other center land portion, each having a base end extending along the tire width direction that is connected to the other middle circumferential groove and a tip end that terminates inside the other center land portion, and alternately arranged with the other first center lug groove in the tire circumferential direction.On the other middle land portion, the base ends extending along the tire width direction communicate with the other middle circumferential grooves, the tip ends terminate inside the other middle land portion, and a plurality of the other first middle lug grooves are provided side by side in the tire circumferential direction; on the other middle land portion, the base ends extending along the tire width direction communicate with the other shoulder circumferential grooves, the tip ends terminate inside the other middle land portion, and a plurality of the other second middle lug grooves are provided side by side in the tire circumferential direction; on the one shoulder land portion, the base ends extending along the tire width direction communicate with the one shoulder circumferential grooves, the tip ends reach the ground contact ends, and a plurality of the one shoulder lug grooves are provided side by side in the tire circumferential direction; on the other shoulder land portion, the base ends extending along the tire width direction communicate with the other shoulder circumferential grooves, the tip ends reach the ground contact ends, and a plurality of the other shoulder lug grooves are provided side by side in the tire circumferential direction; on the one middle land portion, a middle communication sipe extending from the tip end of the one middle lug groove communicates with the one middle circumferential groove; on the one center land portion, a center communication sipe extending from the tip end of the one center lug groove communicates with the center circumferential groove, and the tread portion has these. The maximum dimension L3 in the tire width direction of the other center land portion and the maximum dimension L4 in the tire width direction of the other middle land portion satisfy the relationship L3 < L4. The one middle lug groove, the one center lug groove, the other first center lug groove, the other second center lug groove, the other first middle lug groove, and the other second middle lug groove are provided such that the inclination directions with respect to the tire width direction are alternately opposite. Each of the center lug grooves provided in the other center land portion is provided with a smaller total number arranged in the tire circumferential direction with respect to the middle lug groove in the one middle land portion and each of the middle lug grooves in the other middle land portion. The one shoulder circumferential groove is formed such that each groove wall between the plurality of the one middle lug grooves inclines in the same direction with respect to the tire circumferential direction, and the other circumferential grooves are formed such that the groove walls are linear along the tire circumferential direction.

Effect of the Invention

[0007] According to this invention, the wear resistance performance can be improved while ensuring the ice and snow performance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a meridian cross-sectional view of a pneumatic tire according to an embodiment. [Figure 2] FIG. 2 is a plan view of a tread portion of the pneumatic tire according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view of each circumferential groove of the pneumatic tire according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view of each lug groove of the pneumatic tire according to the first embodiment. [Figure 5] FIG. 5 is a plan view of a tread portion of a pneumatic tire according to the second embodiment. [Figure 6] FIG. 6 is a partially enlarged plan view of a tread of a pneumatic tire according to the second embodiment. [Figure 7] FIG. 7 is a partial cross-sectional view of a pneumatic tire according to the second embodiment. [Figure 8] FIG. 8 is a partial cross-sectional view showing the operation of the pneumatic tire according to the second embodiment. [Figure 9] FIG. 9 is a partial cross-sectional view showing the operation of a typical pneumatic tire. [Figure 10] FIG. 10 is a cross-sectional view showing the shape of the bottom of a wide sipe. [Figure 11] FIG. 11 is a cross-sectional view showing another example of the bottom shape of the wide sipe. [Figure 12] FIG. 12 is a cross-sectional view showing another example of the bottom shape of the wide sipe. [Figure 13] FIG. 13 is a partially enlarged plan view of another example of the tread of the pneumatic tire according to the second embodiment. [Figure 14] FIG. 14 is a partially enlarged plan view of another example of the tread of the pneumatic tire according to the second embodiment. [Figure 15] FIG. 15 is a table showing the results of a performance test of the pneumatic tire according to the embodiment. [Figure 16] FIG. 16 is a table showing the results of a performance test of the pneumatic tire according to the embodiment. [Figure 17] FIG. 17 is a table showing the results of a performance test of the pneumatic tire according to the embodiment. [Figure 18] FIG. 18 is a table showing the results of a performance test of the pneumatic tire according to the embodiment. [Figure 19] FIG. 19 is a table showing the results of a performance test of the pneumatic tire according to the embodiment. [Figure 20] FIG. 20 is a table showing the results of a performance test of the pneumatic tire according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of 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 of these embodiments include those that can be substituted and are obvious substitutes while maintaining the identity of the invention. Furthermore, the multiple modifications described in these embodiments can be arbitrarily combined within the scope obvious to those skilled in the art.

[0010] 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 of this embodiment. 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. 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 equator line refers to a line that is on the tire equatorial plane CL and runs along the tire circumferential direction of the pneumatic tire 1. Also, a cross section in the tire meridian direction (meridian cross section) refers to a cross section of the tire cut by a plane including the tire rotation axis.

[0011] As shown in FIG. 1, a pneumatic tire 1 of the embodiment has a tread portion 2, a sidewall portion 8, and a bead portion 10.

[0012] The tread portion 2 is disposed at the outermost portion in the tire radial direction when viewed in a tire meridian cross section. The tread portion 2 has tread rubber 2A 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 running, is formed as a tread contact surface (also referred to as a tread surface) 2B. The tread contact surface 2B forms part of the contour of the pneumatic tire 1. The tread portion 2 has shoulder portions 2C formed at both outer ends in the tire width direction.

[0013] The sidewall portions 8 are disposed on both sides in the tire width direction of the tread portion 2 and on the inner side in the tire radial direction of the shoulder portions 2C. The sidewall portions 8 are disposed in two locations on both sides in the tire width direction of the pneumatic tire 1, and form the outermost exposed portions of the pneumatic tire 1 in the tire width direction.

[0014] The bead portions 10 are disposed on the radially inner side of each sidewall portion 8. Like the sidewall portions 8, the bead portions 10 are disposed at two locations on both sides 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 radially outer side of the bead core 11 in the tire radial direction. The bead core 11 is an annular member formed by bundling bead wires, which are steel wires, into a circular shape. The bead filler 12 is a rubber member disposed on the radially outer side of the bead core 11 in the tire radial direction.

[0015] The pneumatic tire 1 has an internal structure including a belt layer 14 and a carcass layer 13 .

[0016] The belt layer 14 is disposed on the tread rubber 2A of 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, the belt layer 14 has two layers of belts 141, 142 laminated together.

[0017] The belts 141 and 142 are formed by covering a plurality of belt cords made of steel or organic fiber material such as polyester, rayon, or nylon with a coating rubber and rolling the covered belt cords. The belt angles of the belts 141 and 142, defined as the inclination angle of the belt cords relative to the tire circumferential direction, are within a predetermined range (for example, 20° to 55°). The belt angles of the belts 141 and 142 are different from each other. For this reason, the belts 141 and 142 are formed as a so-called cross-ply structure (cross belt) in which the inclination directions of the belt cords are layered crossing 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. The belt cover 143 has a belt angle, defined as the inclination angle of the belt cover cords with respect to the tire circumferential direction, within a predetermined range (for example, 0° to 10°). The belt cover 143 is formed, for example, by spirally winding a strip material, made of one or more belt cover cords covered with coating rubber, around the tire radially outer side of the two-layer belts 141 and 142 in the tire circumferential direction.

[0019] The carcass layer 13 is disposed continuously on the radially inner side of the belt layer 14 in the tread portion 2, the sidewall portion 8, and the bead portion 10. Both ends of the carcass layer 13 in the tire width direction are wound back and secured to the outer side in the tire width direction so as to enclose the bead cores 11 and bead fillers 12 of both bead portions 10, and are wound around the tire circumferentially in a toroidal shape to form the tire framework. The carcass layer 13 has a single-layer structure consisting of one carcass ply or a multi-layer structure consisting of multiple carcass plies stacked together. The carcass ply of the carcass layer 13 is formed by coating multiple carcass cords made of steel or organic fiber material such as aramid, nylon, polyester, or rayon with coating rubber and rolling them. The carcass cords that make up the carcass ply are arranged side by side at an angle to the tire circumferential direction, with the angle aligned along the tire meridian direction.

[0020] A rim cushion rubber 17 is arranged on the radially inner side and the widthwise outer side of the turned-up portion of the carcass layer 13. The rim cushion rubber 17 forms the contact surface of the bead portion 10 with the rim flange. An inner liner 16 is formed along the carcass layer 13 on the inner side of the carcass layer 13. The inner liner 16 forms the tire inner surface 18, which is the inner surface of the pneumatic tire 1.

[0021] 1 and 2, a pneumatic tire 1 of the embodiment has a tread pattern on a tread contact surface 2B of a tread portion 2. Here, each dimension of the tread pattern is measured in an unloaded state with the tire mounted on a specified rim and inflated to a specified internal pressure.

[0022] Specified rim refers to the "standard rim" specified by JATMA, the "design rim" specified by TRA, or the "measuring rim" specified by ETRTO. Specified internal pressure refers to the "maximum air pressure" specified by JATMA, the maximum value of the "tire load limits at various cold inflation pressures" specified by TRA, or the "inflation pressures" specified by ETRTO. Specified load refers to the "maximum load capacity" specified by JATMA, the maximum value of the "tire load limits at various cold inflation pressures" specified by TRA, or the "load capacity" specified by ETRTO.

[0023] The groove width (also called the open groove width) is measured as the maximum distance between the opposing groove walls at the groove opening at the tread contact surface 2B when the tire is mounted on a specified rim, inflated to a specified internal pressure, and in an unloaded state. In addition, when the groove opening has a notch or chamfer, the groove width is measured using the intersection of an extension of the tread contact surface 2B and an extension of the groove wall as the endpoint in a cross section parallel to the tire width direction and the tire radial direction.

[0024] The groove depth is measured as the maximum distance from the tread contact surface 2B to the groove bottom when the tire is mounted on a specified rim, inflated to a specified internal pressure, and under no load. If the tire has partial unevenness or sipes at the groove bottom, the groove depth is measured excluding these.

[0025] [Embodiment 1] 1 and 2, the pneumatic tire 1 of the first embodiment mainly includes, as a tread pattern, a center circumferential groove 30, a middle circumferential groove 31, and shoulder circumferential grooves 32. Each of the circumferential grooves 30, 31, and 32 may be defined as a groove that is required to display a wear indicator as defined by JATMA.

[0026] The center circumferential groove 30 extends along the tire circumferential direction and has an annular structure provided continuously around the entire tire circumference. One center circumferential groove 30 is provided closest to the tire equatorial plane CL. The center circumferential groove 30 may be provided on the tire equatorial plane CL. The center circumferential groove 30 is formed linearly along the tire circumferential direction without any bends. As shown in FIG. 3 , the center circumferential groove 30 has a maximum groove width W of 3.0 mm or more and 13.0 mm or less in a cross section perpendicular to the tire circumferential direction, and a groove depth D of 7.0 mm or more and 10.0 mm or less.

[0027] The middle circumferential groove 31 extends in the tire circumferential direction and has an annular structure provided continuously around the entire tire circumference. Two middle circumferential grooves 31 are provided in the tire width direction, sandwiching the center circumferential groove 30 therebetween. The middle circumferential grooves 31 are formed in straight lines without any bends along the tire circumferential direction. As shown in FIG. 3 , the middle circumferential groove 31 has a maximum groove width W of 3.0 mm or more and 13.0 mm or less in a cross section perpendicular to the tire circumferential direction, and a groove depth D of 7.0 mm or more and 10.0 mm or less.

[0028] The shoulder circumferential grooves 32 extend in the tire circumferential direction and have an annular structure that is continuously provided around the entire tire circumference. One shoulder circumferential groove 32 is provided on each of the two middle circumferential grooves 31 on the outer side in the tire width direction. The shoulder circumferential grooves 32 are formed in a straight line along the tire circumferential direction without any bends. As shown in FIG. 3 , the shoulder circumferential grooves 32 have a maximum groove width W of 3.0 mm or more and 13.0 mm or less in a cross section perpendicular to the tire circumferential direction, and a groove depth D of 7.0 mm or more and 10.0 mm or less.

[0029] In the pneumatic tire 1 of the embodiment, a plurality of land portions 20 are defined in the tread portion 2 by one center circumferential groove 30, two middle circumferential grooves 31, and two shoulder circumferential grooves 32. The land portions 20 include a center land portion 21, a middle land portion 22, and a shoulder land portion 23. The center land portion 21 is formed in two rib-like rows along the tire circumferential direction between the one center circumferential groove 30 and each middle circumferential groove 31. The middle land portions 22 are defined between each middle circumferential groove 31 and each shoulder circumferential groove 32, and are formed in a total of two rib-like rows along the tire circumferential direction on both outer sides of each center land portion 21 in the tire width direction. The shoulder land portions 23 are defined outward in the tire width direction from each shoulder circumferential groove 32, and are formed in a total of two rib-like rows along the tire circumferential direction on the outer sides of each middle land portion 22 in the tire width direction. The shoulder land portions 23 include the ground contact edges T.

[0030] Here, the ground contact edges T refer to the outermost ends in the tire width direction in the area where the tread contact surface 2B of the pneumatic tire 1 comes into contact with the road surface when the pneumatic tire 1 is mounted on a standard rim, inflated to a standard internal pressure, and subjected to 70% of a standard load, and are continuous in the tire circumferential direction.

[0031] Furthermore, the pneumatic tire 1 of the embodiment has a specified orientation relative to the vehicle width direction when mounted on a vehicle. The pneumatic tire 1 of the embodiment has a defined orientation relative to the vehicle width direction (tire width direction) when mounted on a vehicle, i.e., a defined inner side in the vehicle width direction and an outer side in the vehicle width direction. Specifically, the pneumatic tire 1 includes a mounting direction indicator (not shown) that indicates the tire mounting direction relative to the vehicle. The mounting direction indicator is configured, for example, by a mark or a concavo-convex portion attached to the tire sidewall. For example, Article 30 of the Economic Commission for Europe Regulation (ECER) requires that a vehicle mounting direction indicator be provided on the sidewall portion that will be on the outer side in the vehicle width direction when mounted on a vehicle. Note that in the embodiment, the outer side in the vehicle width direction may be expressed as "one side" and the inner side in the vehicle width direction as "the other side." This does not exclude the use of "one side" and "the other side" in reverse, referring to the inner and outer sides in the vehicle width direction.

[0032] Therefore, in the pneumatic tire 1 of the embodiment, the middle circumferential grooves 31 are composed of a middle circumferential groove 31A on the outer side in the vehicle width direction (also referred to as an outer middle circumferential groove or one of the middle circumferential grooves) and a middle circumferential groove 31B on the inner side in the vehicle width direction (also referred to as an inner middle circumferential groove or the other of the middle circumferential grooves). Also, in the pneumatic tire 1 of the embodiment, the shoulder circumferential grooves 32 are composed of a shoulder circumferential groove 32A on the outer side in the vehicle width direction (also referred to as an outer shoulder circumferential groove or one of the shoulder circumferential grooves) and a shoulder circumferential groove 32B on the inner side in the vehicle width direction (also referred to as an inner shoulder circumferential groove or the other of the shoulder circumferential grooves).

[0033] In addition, the pneumatic tire 1 of the embodiment has a center land portion 21 that is an outer center land portion in the vehicle width direction (also referred to as an outer center land portion or one center land portion) 21A and an inner center land portion in the vehicle width direction (also referred to as an inner center land portion or the other center land portion) 21B. In the pneumatic tire 1 of the embodiment, the tire equatorial plane CL is located at the inner center land portion 21B. In addition, the pneumatic tire 1 of the embodiment has a middle land portion 22 that is an outer middle land portion in the vehicle width direction (also referred to as an outer middle land portion or one middle land portion) 22A and an inner middle land portion in the vehicle width direction (also referred to as an inner middle land portion or the other middle land portion) 22B. In addition, in the pneumatic tire 1 of the embodiment, the shoulder land portions 23 that are an outer shoulder land portion in the vehicle width direction (also referred to as an outer shoulder land portion or one shoulder land portion) 23A and an inner shoulder land portion in the vehicle width direction (also referred to as an inner shoulder land portion or the other shoulder land portion) 23B.

[0034] As shown in FIG. 2, the pneumatic tire 1 of the embodiment has an outer middle lug groove (also referred to as one middle lug groove) 41, a middle connecting sipe 51, and an outer middle sipe (also referred to as one middle sipe) 61a (sipe 61) provided in the outer middle land portion 22A.

[0035] The outer middle lug groove 41 extends along the tire width direction, with its base end 41a communicating with the outer shoulder circumferential groove 32A and its tip end 41b terminating inside the outer middle land portion 22A, so that it does not penetrate the outer middle land portion 22A. The outer middle lug groove 41 is formed at an angle with respect to the tire width direction. The outer middle lug groove 41 has a widest groove width at its base end 41a and gradually decreases in width toward its tip end 41b. Multiple outer middle lug grooves 41 are formed side by side in the tire circumferential direction at intervals. The angle θ1 of the centerline of each outer middle lug groove 41 with respect to the tire width direction is in the range of 10°≦θ1≦40°. This angle θ1 is expressed as an absolute value and can be either positive or negative with respect to the tire width direction. In the embodiment, the outer middle lug groove 41 is formed to extend linearly, but it is not limited to a linear shape and may be bent or curved. When the outer middle lug groove 41 is bent or curved, the angle θ1 of the outer middle lug groove 41 is based on the center line of the straight line connecting the base end 41a and the tip end 41b. As shown in Figures 2 and 4, the outer middle lug groove 41 has a maximum groove width W1 of 1.5 mm to 7.0 mm in a cross section perpendicular to the center line, and a groove depth D1 of 7.0 mm to 10.0 mm.

[0036] The outer middle lug groove 41 has a maximum length La in the tire width direction and a maximum dimension L1 in the tire width direction of the outer middle land portion 22A such that the relationship is 0.50≦La / L1≦0.90.

[0037] The outer shoulder circumferential grooves 32A, which are connected to the outer middle lug grooves 41, have groove walls 32Aa formed between the multiple outer middle lug grooves 41 such that the groove walls 32Aa on the outer middle land portion 22A side are inclined in the same direction relative to the tire circumferential direction. That is, the groove walls 32Aa of the outer shoulder circumferential grooves 32A on the outer middle land portion 22A side (inner side in the vehicle width direction) are formed so that they gradually increase and decrease in the tire circumferential direction between the outer middle lug grooves 41, and all are formed in the same inclination direction. Therefore, the groove walls 32Aa of the outer shoulder circumferential grooves 32A on the outer middle land portion 22A side are formed jaggedly along the tire circumferential direction. Note that the groove walls of the outer shoulder circumferential grooves 32A on the outer shoulder land portion 23A side are formed linearly (parallel) along the tire circumferential direction. The other circumferential grooves 30, 31A, 31B, and 32B have groove walls formed linearly (parallel) along the tire circumferential direction.

[0038] The middle communicating sipe 51 extends linearly without bending from the tip 41b of the outer middle lug groove 41 along the extension direction of the outer middle lug groove 41, and communicates with the outer middle circumferential groove 31A. The middle communicating sipe 51 has a width of 0.3 mm or more and 1.5 mm or less, and a depth of 2.0 mm or more and 10.0 mm or less.

[0039] The outer middle sipes 61a extend along (in the embodiment, parallel to) the slope of the outer middle lug groove 41, and a plurality of outer middle sipes 61a are arranged side by side in the tire circumferential direction. The ends of the outer middle sipes 61a may terminate inside the outer middle land portion 22A, or may communicate with the outer middle circumferential groove 31A or the outer shoulder circumferential groove 32A.

[0040] The sipes 61, including the outer middle sipes 61a, may have a shape at the tread contact surface 2B that is linear, curved, wavy, or zigzag. The sipes 61 may have a shape inside the tread rubber 2A that is linear or uneven in the depth direction or extension direction. In this embodiment, the sipes 61 are formed in a zigzag shape at the tread contact surface 2B, and are formed in a linear or uneven shape inside the tread rubber 2A. The sipes 61 have a width of 1.0 mm or less and a depth of 2.0 mm or more and 10.0 mm or less.

[0041] Furthermore, the "sipes" referred to in the embodiments are formed in the shape of narrow grooves in the tread contact surface 2B, and when the pneumatic tire 1 is mounted on a specified rim and under specified internal pressure conditions, the wall surfaces constituting the narrow grooves may not come into contact with each other when no load is applied; however, when a load is applied vertically on a flat plate and the narrow groove is located in the contact surface formed on the flat plate, or when the land portion where the narrow groove is formed collapses, the wall surfaces constituting the narrow grooves, or at least a portion of the portion provided on the wall surface, come into contact with each other due to deformation of the land portion.

[0042] As shown in FIG. 2, the pneumatic tire 1 of the embodiment has outer center lug grooves (also referred to as one center lug groove) 42, center connecting sipes 52, and outer center sipes (also referred to as one center sipe) 61b (sipe 61) provided in the outer center land portion 21A.

[0043] The outer center lug grooves 42 extend along the tire width direction, with their base ends 42a communicating with the outer middle circumferential grooves 31A and their tips 42b terminating inside the outer center land portion 21A, so that they do not penetrate the outer center land portion 21A. The outer center lug grooves 42 are formed at an angle with respect to the tire width direction. The outer center lug grooves 42 are widest at their base ends 42a and gradually decrease in width toward their tips 42b. Multiple outer center lug grooves 42 are formed side by side in the tire circumferential direction at intervals. The outer center lug grooves 42 have a centerline angle θ2 with respect to the tire width direction in the range of 10°≦θ2≦40°. This angle θ2 is expressed as an absolute value and can be either positive or negative with respect to the tire width direction. In the embodiment, the outer center lug grooves 42 are formed to extend linearly, but they may be bent or curved. When the outer center lug groove 42 is bent or curved, the angle θ2 of the outer center lug groove 42 is based on the center line of the straight line connecting the base end 42a and the tip end 42b. As shown in Figures 2 and 4, the outer center lug groove 42 has a maximum groove width W2 of 1.5 mm to 7.0 mm in a cross section perpendicular to the center line, and a groove depth D2 of 7.0 mm to 10.0 mm.

[0044] Furthermore, the outer center lug groove 42 has a maximum length Lb in the tire width direction and a maximum dimension L2 in the tire width direction of the center land portion 21 that satisfy the relationship 0.55≦Lb / L2≦0.95.

[0045] The center communicating sipes 52 extend linearly without bending from the tips 42b of the outer center lug grooves 42 along the extension direction of the outer center lug grooves 42, and communicate with the center circumferential grooves 30. The center communicating sipes 52 have a width of 0.3 mm or more and 1.5 mm or less, and a depth of 2.0 mm or more and 10.0 mm or less.

[0046] The outer center sipes 61b extend along the slope of the outer center lug grooves 42 (in this embodiment, parallel to the slope), and a plurality of outer center sipes 61b are arranged side by side in the tire circumferential direction. The ends of the outer center sipes 61b may terminate inside the outer center land portion 21A, or may communicate with the outer middle circumferential grooves 31A or the center circumferential groove 30.

[0047] As shown in FIG. 2, the pneumatic tire 1 of the embodiment has an inner first center lug groove (also referred to as the other first center lug groove) 43, an inner second center lug groove (also referred to as the other second center lug groove) 44, and an inner center sipe (also referred to as the other center sipe) 61c (sipe 61) provided in the inner center land portion 21B.

[0048] The inner first center lug grooves 43 extend along the tire width direction, with their base ends 43a communicating with the center circumferential groove 30 and their tips 43b communicating with the inner middle circumferential grooves 31B, thereby penetrating the inner center land portion 21B. The inner first center lug grooves 43 are formed at an angle with respect to the tire width direction. The inner first center lug grooves 43 are widest at their base ends 43a and gradually decrease in width toward their tips 43b. Multiple inner first center lug grooves 43 are arranged side by side in the tire circumferential direction at intervals. The inner first center lug grooves 43 have a centerline angle θ3 with respect to the tire width direction in the range of 5°≦θ3≦35°. This angle θ3 is expressed as an absolute value and has either a positive or negative angle with respect to the tire width direction. In the embodiment, the inner first center lug grooves 43 are formed to extend linearly, but they may be bent or curved. When the inner first center lug groove 43 is bent or curved, the angle θ3 of the inner first center lug groove 43 is based on the center line of the straight line connecting the base end 43a and the tip end 43b. As shown in Figures 2 and 4, the inner first center lug groove 43 has a maximum groove width W3 of 1.5 mm to 7.0 mm in a cross section perpendicular to the center line, and a groove depth D3 of 7.0 mm to 10.0 mm.

[0049] The inner second center lug grooves 44 extend along the tire width direction, with their base ends 44a communicating with the inner middle circumferential groove 31B and their tips 44b terminating inside the center land portion 21, so that they do not penetrate the inner center land portion 21B. The inner second center lug grooves 44 are formed at an angle with respect to the tire width direction. The inner second center lug grooves 44 are formed so that their groove width is narrowest at their base ends 44a and gradually increases toward their tips 44b. Multiple inner second center lug grooves 44 are formed side by side at intervals in the tire circumferential direction. In the embodiment, the inner second center lug grooves 44 are formed to extend linearly, but may be formed to be bent or curved, not limited to a linear shape. The inner second center lug grooves 44 are arranged alternately with the inner first center lug grooves 43 in the tire circumferential direction.

[0050] The inner second center lug groove 44 has a maximum length Lc in the tire width direction and a maximum dimension L3 in the tire width direction of the inner center land portion 21B that satisfy the relationship 0.30≦Lc / L3≦0.50.

[0051] The inner center sipes 61c extend along (in the embodiment, parallel to) the inclination of the inner first center lug grooves 43, and a plurality of inner center sipes 61c are provided side by side in the tire circumferential direction. The ends of the inner center sipes 61c may terminate inside the inner center land portion 21B, or may communicate with the center circumferential groove 30 or the inner middle circumferential groove 31B.

[0052] As shown in FIG. 2, the pneumatic tire 1 of the embodiment has an inner first middle lug groove (also referred to as the other first middle lug groove) 45, an inner second middle lug groove (also referred to as the other second middle lug groove) 46, an inner first middle sipe (also referred to as the other first middle sipe) 61d (sipe 61), and an inner second middle sipe (also referred to as the other second middle sipe) 61e (sipe 61) in the inner middle land portion 22B.

[0053] The inner first middle lug groove 45 extends along the tire width direction, with its base end 45a communicating with the inner middle circumferential groove 31B and its tip end 45b terminating inside the inner middle land portion 22B, thereby not penetrating the inner middle land portion 22B. The inner first middle lug groove 45 is formed at an angle with respect to the tire width direction. The inner first middle lug groove 45 has a widest groove width at its base end 45a and gradually decreases in width toward its tip end 45b. Multiple inner first middle lug grooves 45 are arranged side by side in the tire circumferential direction at intervals. In the embodiment, the inner first middle lug groove 45 is formed to extend linearly, but may be bent or curved. When the inner first middle lug groove 45 is bent or curved, the inclination angle of the inner first middle lug groove 45 is based on the center line of the straight line connecting the base end 45a and the tip end 45b. 2 and 4, the inner first middle lug groove 45 has a maximum groove width W4 of 1.5 mm to 7.0 mm in a cross section perpendicular to the centerline and a groove depth D4 of 4.0 mm to 10.0 mm. The inner first middle lug groove 45 has a raised bottom.

[0054] The maximum length Ld of the inner first middle lug groove 45 in the tire width direction and the maximum dimension L4 of the inner middle land portion 22B in the tire width direction satisfy the relationship 0.30≦Ld / L4≦0.70.

[0055] Furthermore, the base ends 45a of every other inner first middle lug groove 45 aligned in the tire circumferential direction face the tip ends 43b of the inner first center lug grooves 43 and the base ends 44a of the inner second center lug grooves 44 in the tire width direction, with the inner middle circumferential groove 31B as the boundary. That is, every other inner first middle lug groove 45 aligned in the tire circumferential direction is arranged contiguous to the inner first center lug groove 43 and the inner second center lug groove 44, with the inner middle circumferential groove 31B as the boundary. The inner first middle lug grooves 45 are arranged at an inclination angle that is the same as the angle θ3 of the center line of the inner first center lug groove 43 relative to the tire width direction. The inner second center lug grooves 44 are inclined in the same direction as the inner first center lug grooves 43, and are arranged at the same inclination angle θ3 as the angle of the center line of the inner first center lug grooves 43 with respect to the tire width direction, and have a maximum groove width of 1.5 mm or more and 7.0 mm or less in a cross section perpendicular to the center line, and a groove depth of 7.0 mm or more and 10.0 mm or less.

[0056] The inner second middle lug groove 46 extends along the tire width direction, with its base end 46a communicating with the inner shoulder circumferential groove 32B and its tip end 46b terminating inside the inner middle land portion 22B, thereby not penetrating the inner middle land portion 22B. The inner second middle lug groove 46 is formed at an angle with respect to the tire width direction. The inner second middle lug groove 46 has a widest groove width at its base end 46a and gradually decreases in width toward its tip end 46b. Multiple inner second middle lug grooves 46 are arranged side by side in the tire circumferential direction at intervals. The inner second middle lug grooves 46 have a centerline angle θ4 with respect to the tire width direction in the range of 1°≦θ4≦20°. This angle θ4 is expressed as an absolute value and can be either positive or negative with respect to the tire width direction. In the embodiment, the inner second middle lug groove 46 is formed to extend linearly, but it may be bent or curved. When the inner second middle lug groove 46 is bent or curved, the angle θ4 of the inner second middle lug groove 46 is based on the center line of the straight line connecting the base end 46a and the tip end 46b. As shown in Figures 2 and 4, the inner second middle lug groove 46 has a maximum groove width W5 of 1.5 mm to 7.0 mm in a cross section perpendicular to the center line and a groove depth D4 of 7.0 mm to 10.0 mm.

[0057] The maximum length Le of the inner second middle lug groove 46 in the tire width direction and the maximum dimension L4 of the inner middle land portion 22B in the tire width direction satisfy the relationship 0.10≦Le / L4≦0.50.

[0058] The inner second middle lug grooves 46 and the inner first middle lug grooves 45 are arranged alternately in the tire circumferential direction.

[0059] The inner first middle sipes 61d extend along (in the embodiment, parallel to) the slope of the inner first middle lug grooves 45, and a plurality of inner first middle sipes 61d are arranged side by side in the tire circumferential direction. An end of each inner first middle sipe 61d may terminate inside the inner middle land portion 22B, or one end may be connected to the inner middle circumferential groove 31B.

[0060] The inner second middle sipes 61e extend along (in the embodiment, parallel to) the slope of the inner second middle lug groove 46, and a plurality of them are provided side by side in the tire circumferential direction. An end of the inner second middle sipe 61e may terminate inside the inner middle land portion 22B, or one end may be connected to the inner shoulder circumferential groove 32B.

[0061] The inner second middle sipe 61e may be connected to the inner first middle sipe 61d at the other end, but in this embodiment, they are arranged at an interval in the tire width direction.

[0062] As shown in Figure 2, the pneumatic tire 1 of the embodiment has an outer shoulder lug groove (also referred to as one shoulder lug groove) 47, an outer shoulder sipe (also referred to as one shoulder sipe) 61f (sipe 61), and an outer shoulder circumferential groove 71 provided in the outer shoulder land portion 23A.

[0063] The outer shoulder lug grooves 47 extend along the tire width direction, with their base ends 47a communicating with the outer shoulder circumferential groove 32A and extending outward in the tire width direction, passing through the ground contact edge T. The outer shoulder lug grooves 47 are formed at an angle with respect to the tire width direction. Multiple outer shoulder lug grooves 47 are arranged side by side in the tire circumferential direction at intervals. The base ends 47a of the outer shoulder lug grooves 47 face the base ends 41a of the outer middle lug grooves 41 in the tire width direction, with the outer shoulder circumferential groove 32A as the boundary. In other words, the same number of outer shoulder lug grooves 47 as the outer middle lug grooves 41 are arranged, and they are continuous with the outer middle lug grooves 41, with the outer shoulder circumferential groove 32A as the boundary. The outer shoulder lug grooves 47 are inclined in the opposite direction to the outer middle lug grooves 41, and the angle of the center line relative to the tire width direction is in the range of 1° to 15° in absolute value, the maximum groove width in the cross section perpendicular to the center line is 1.5 mm to 7.0 mm, and the groove depth is 5.0 mm to 10.0 mm.

[0064] The outer shoulder sipes 61f extend along (in the embodiment, parallel to) the slope of the outer shoulder lug grooves 47, and a plurality of outer shoulder sipes 61f are provided side by side in the tire circumferential direction. The ends of the outer shoulder sipes 61f may terminate inside the outer shoulder land portion 23A, or may communicate with the outer shoulder circumferential groove 32A.

[0065] The outer shoulder circumferential grooves 71 are arranged linearly without any bends along the tire circumferential direction between the outer shoulder circumferential groove 32A and the ground contact edge T. They are arranged between the outer shoulder lug grooves 47 that are aligned in the tire circumferential direction, with one end communicating with one of the outer shoulder lug grooves 47 and the other end terminating inside the outer shoulder land portion 23A. The outer shoulder circumferential grooves 71 are aligned in a row in the tire circumferential direction. The outer shoulder circumferential grooves 71 do not communicate with the outer shoulder sipes 61f but divide the outer shoulder sipes 61f in the tire width direction. The outer shoulder circumferential grooves 71 have a groove width of 0.5 mm or more and 2.5 mm or less and a groove depth of 0.5 mm or more and 3.5 mm or less.

[0066] As shown in Figure 2, the pneumatic tire 1 of the embodiment has an inner shoulder lug groove (also referred to as the other shoulder lug groove) 48, an inner shoulder sipe (also referred to as the other shoulder sipe) 61g (sipe 61), and an inner shoulder circumferential groove 72 provided in the inner shoulder land portion 23B.

[0067] The inner shoulder lug grooves 48 extend along the tire width direction, with their base ends 48a communicating with the inner shoulder circumferential groove 32B and extending outward in the tire width direction, passing through the ground contact edge T. The inner shoulder lug grooves 48 are formed at an angle with respect to the tire width direction. Multiple inner shoulder lug grooves 48 are arranged side by side in the tire circumferential direction at intervals. The base ends 48a of the inner shoulder lug grooves 48 face the base ends 46a of the inner second middle lug grooves 46 in the tire width direction, with the inner shoulder circumferential groove 32B as the boundary. In other words, the number of inner shoulder lug grooves 48 is the same as the number of inner second middle lug grooves 46, and they are arranged contiguous with the inner second middle lug grooves 46, with the inner shoulder circumferential groove 32B as the boundary. The inner shoulder lug groove 48 is inclined in the same direction as the inner second middle lug groove 46, the angle of the center line relative to the tire width direction is in the range of 1° or more and 15° or less in absolute value, the maximum groove width in the cross section perpendicular to the center line is 1.5 mm or more and 7.0 mm or less, and the groove depth is 5.0 mm or more and 10.0 mm or less.

[0068] The inner shoulder sipes 61g extend along (in the embodiment, parallel to) the inner shoulder lug grooves 48, and a plurality of inner shoulder sipes 61g are provided side by side in the tire circumferential direction. The ends of the inner shoulder sipes 61g may terminate inside the inner shoulder land portion 23B, or may communicate with the inner shoulder circumferential groove 32B.

[0069] The inner shoulder circumferential groove 72 is arranged linearly without a bend along the tire circumferential direction between the inner shoulder circumferential groove 32B and the ground contact edge T, and is arranged between the inner shoulder lug grooves 48 lined up in the tire circumferential direction, with one end communicating with one of the inner shoulder lug grooves 48 and the other end terminating inside the inner shoulder land portion 23B. The inner shoulder circumferential grooves 72 are arranged in a line in the tire circumferential direction. The inner shoulder circumferential groove 72 does not communicate with the inner shoulder sipe 61g and divides the inner shoulder sipe 61g in the tire width direction. The inner shoulder circumferential groove 72 has a groove width of 0.5 mm or more and 2.5 mm or less and a groove depth of 0.5 mm or more and 3.5 mm or less.

[0070] 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. When a vehicle mounted with the pneumatic tire 1 runs, the pneumatic tire 1 rotates while the lower tread contact surface 2B of the tread portion 2 comes into contact with the road surface. When a vehicle mounted with the pneumatic tire 1 runs on a dry road surface, the vehicle runs by transmitting driving force and braking force to the road surface and generating turning force mainly due to friction between the tread contact surface 2B and the road surface.

[0071] Furthermore, when traveling on a wet road surface, water between the tread surface 2B and the road surface enters each of the grooves 30, 31, 32, 41, 42, 43, 44, 45, 46, 47, 48 and the sipes 51, 52, 61, and the water between the tread surface 2B and the road surface is drained while traveling. This makes it easier for the tread surface 2B to make contact with the road surface, and the friction between the tread surface 2B and the road surface provides wet performance, enabling the vehicle to travel.

[0072] Furthermore, when traveling on snowy roads, the pneumatic tire 1 compacts snow on the road surface with the tread contact surface 2B, and snow on the road surface enters each of the grooves 30, 31, 32, 41, 42, 43, 44, 45, 46, 47, and 48, compacting the snow within the grooves. 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 and snow performance. This allows the vehicle to travel on snowy roads.

[0073] Furthermore, when traveling on snowy or icy road surfaces, the tire also utilizes the edge effect of the grooves 30, 31, 32, 41, 42, 43, 44, 45, 46, 47, and 48 and the sipes 51, 52, and 61. That is, when traveling on snowy or icy road surfaces, the tire also utilizes the resistance created by the edges of the grooves 30, 31, 32, 41, 42, 43, 44, 45, 46, 47, and 48 and the sipes 51, 52, and 61 catching on the snow or ice surface. Furthermore, when traveling on icy road surfaces, the sipes 61 absorb water on the surface of the icy road surface, removing the water film between the icy road surface and the tread contact surface 2B, thereby facilitating contact between the icy road surface and the tread contact surface 2B. As a result, the resistance between the tread contact surface 2B and the icy road surface increases due to frictional force and the edge effect, thereby improving ice performance. This allows the vehicle to travel on icy roads.

[0074] The grooves 30, 31, 32, 41, 42, 43, 44, 45, 46, 47, 48 and sipes 51, 52, 61 formed in the tread portion 2 contribute to ensuring running performance when running on wet, snowy, or icy road surfaces, so that in order to improve wet performance, i.e., running performance on wet road surfaces, it is effective to increase the groove area of ​​the tread portion 2. In other words, if the groove area of ​​the grooves 30, 31, 32, 41, 42, 43, 44, 45, 46, 47, 48, etc. is increased, water on the road surface can easily enter the grooves when running on a wet road surface, thereby improving the drainage of water between the tread contact surface 2B and the road surface and improving wet performance.

[0075] Increasing the groove area also effectively improves snow performance, which is driving performance on snowy roads. In other words, increasing the groove area increases the amount of snow that can enter each groove 30, 31, 32, 41, 42, 43, 44, 45, 46, 47, and 48 when driving on snowy roads, thereby increasing the snow column shear force acting on the snow that has entered the grooves. This improves snow traction when driving on snowy roads, and improves snow performance.

[0076] The pneumatic tire 1 of the embodiment is characterized by having one center circumferential groove 30 formed linearly along the tire circumferential direction and arranged closest to the tire equatorial plane CL, one middle circumferential groove (outer middle circumferential groove) 31A and the other middle circumferential groove (inner middle circumferential groove) 31B formed linearly along the tire circumferential direction and arranged on either side of the center circumferential groove 30, and one shoulder circumferential groove (outer shoulder circumferential groove) 32A and the other shoulder circumferential groove (inner shoulder circumferential groove) 32B formed linearly along the tire circumferential direction and arranged on the outer side of each of the middle circumferential grooves 31A, 31B in the tire width direction. a shoulder circumferential groove (inner shoulder circumferential groove) 32B, one center land portion (outer center land portion) 21A defined between the center circumferential groove 30 and one middle circumferential groove 31A, the other center land portion (inner center land portion) 21B defined between the center circumferential groove 30 and the other middle circumferential groove 31B, one middle land portion (outer middle land portion) 22A defined between one middle circumferential groove 31A and one shoulder circumferential groove 32A, and the other middle land portion (inner middle land portion) defined between the other middle circumferential groove 31B and the other shoulder circumferential groove 32B. a shoulder land portion (outer shoulder land portion) 23A defined on the tire width direction outer side of one shoulder circumferential groove 32A; a shoulder land portion (inner shoulder land portion) 23B defined on the tire width direction outer side of the other shoulder circumferential groove 32B; a middle lug groove (outer middle lug groove) 41 extending along the tire width direction in one middle land portion 22A, with a base end 41a connected to one shoulder circumferential groove 32A and a tip end 41b terminating inside one middle land portion 22A, and arranged in a row in the tire circumferential direction; one center lug groove (outer center lug groove) 42 arranged in a row in the tire circumferential direction in the land portion 21A, with base ends 42a extending along the tire width direction communicating with one middle circumferential groove 31A and with tips 42b terminating inside the one center land portion 21A; and the other first center lug groove (inner first center lug groove) 43 arranged in a row in the tire circumferential direction in the other center land portion 21B, with base ends 43a extending along the tire width direction communicating with the center circumferential groove 30 and tips 43b penetrating the other center land portion 21B and communicating with the other middle circumferential groove 31B;At the other center land portion 21B, a base end 44a extending along the tire width direction communicates with the other middle circumferential groove 31B, a tip end 44b terminates inside the other center land portion 21B, and a plurality of them are provided side by side in the tire circumferential direction. The other second center lug groove (inner second center lug groove) 44 is alternately arranged with the other first center lug groove 43 in the tire circumferential direction. At the other middle land portion 22B, a base end 45a extending along the tire width direction communicates with the other middle circumferential groove 31B, a tip end 45b terminates inside the other middle land portion 22B, and a plurality of the other first middle lug grooves (inner first middle lug grooves) 45 are provided side by side in the tire circumferential direction. At the other middle land portion 22B, a base end 46a extending along the tire width direction communicates with the other shoulder circumferential groove 32B, a tip end 46b terminates inside the other middle land portion 22B, and a plurality of the other second middle lug grooves (inner second middle lug grooves) 46 are provided side by side in the tire circumferential direction. At one shoulder land portion 23A, a base end 47a extending along the tire width direction communicates with one shoulder circumferential groove 32A, the tip end side reaches the ground contact end T, and a plurality of one shoulder lug grooves (outer shoulder lug grooves) 47 are provided side by side in the tire circumferential direction. At the other shoulder land portion 23B, a base end 48a extending along the tire width direction communicates with the other shoulder circumferential groove 32B, the tip end side reaches the ground contact end T, and a plurality of the other shoulder lug grooves (inner shoulder lug grooves) 48 are provided side by side in the tire circumferential direction. At one middle land portion 22A, a middle communication sipe 51 extends from the tip end 41b of one middle lug groove 41 and communicates with one middle circumferential groove 31A. At one center land portion 21A, a center communication sipe 52 extends from the tip end 42b of one center lug groove 42 and communicates with the center circumferential groove 30. The tread portion 2 has these. The maximum dimension L3 in the tire width direction of the other center land portion 21B and the maximum dimension L4 in the tire width direction of the other middle land portion 22B satisfy the relationship of L3 < L4. One middle lug groove 41, one center lug groove 42, the other first center lug groove 43, the other second center lug groove 44, the other first middle lug groove 45, and the other second middle lug groove 46 are provided such that the inclination directions with respect to the tire width direction are alternately opposite. Each center lug groove 43, 44 provided at the other center land portion 21B is the middle lug groove 41 of one middle land portion 22A.The total number of middle lug grooves 45, 46 of the other middle land portion 22B is smaller than the total number of middle lug grooves 45, 46 of the other middle land portion 22B. In one shoulder circumferential groove 32A, the groove walls 32Aa between the plurality of one middle lug grooves 41 are formed so as to be inclined in the same direction relative to the tire circumferential direction, and the groove walls of the other circumferential grooves 30, 31A, 31B, 32B are formed so as to be linearly aligned along the tire circumferential direction.

[0077] According to the pneumatic tire 1 of the embodiment, by making the inclination directions of the lug grooves 41, 42, 43-45, 46 of the adjacent land portions 22A, 21A, 21B, 22B not in the same direction, it is possible to improve the snow shear force because it does not deviate at a specific angle. Further, according to the pneumatic tire 1 of the embodiment, since the other center lug groove 43 penetrates the other center land portion 21B, the traction performance on ice and snow can be enhanced. Further, according to the pneumatic tire 1 of the embodiment, by satisfying the relationship of L3 < L4 between the maximum dimension L3 in the tire width direction of the other center land portion 21B and the maximum dimension L4 in the tire width direction of the other middle land portion 22B, it is possible to improve the abrasion resistance without sacrificing the ice performance. Further, according to the pneumatic tire 1 of the embodiment, by arranging the communication sipes 51, 52 at the tips 41b, 42b where the lug grooves 41, 42 are terminated inside the land portions 22A, 21A, while improving the snow column shear force, the rigidity of the land portions 22A, 21A is ensured and the collapse is suppressed, and it is possible to improve the ice and snow performance and the abrasion resistance performance. Further, according to the pneumatic tire 1 of the embodiment, the communication sipes 51, 52 are provided near the center portion in the tire width direction, and since this center portion is related to the traction performance at the time of starting, the traction performance on ice and snow can be enhanced by penetrating the land portions 22A, 21A with the communication sipes 51, 52. Further, according to the pneumatic tire 1 of the embodiment, since the total number of the lug grooves 43, 44 of the other center land portion 21B arranged in the tire circumferential direction with respect to the other lug grooves 41, 45, 46 is small, while obtaining the snow column shear force by the lug grooves 43, 44, the rigidity of the other center land portion 21B is ensured, and it is possible to improve the abrasion resistance performance. Note that according to the pneumatic tire 1 of the embodiment, the total number of the lug grooves 42 of the one center land portion 21A arranged in the tire circumferential direction with respect to the other lug grooves 41, 45, 46 is also small, so that while obtaining the snow column shear force by the lug grooves 42, the rigidity of the other center land portion 21A is ensured, and the abrasion resistance performance is also improved. Further, according to the pneumatic tire 1 of the embodiment, in the one shoulder circumferential groove 32A, each groove wall 32Aa between the plurality of lug grooves 41 is formed to be inclined in the same direction with respect to the tire circumferential direction, so that the drainage performance and the snow column shear force are improved, and the ice and snow performance is improved.As a result, the pneumatic tire 1 can improve wear resistance while ensuring snow and ice performance.

[0078] In addition, in the pneumatic tire 1 of the embodiment, the other first center lug groove 43 and the other second center lug groove 44 are arranged in a smaller number in the circumferential direction of the tire than the other lug grooves 41, 45, and 46, and are provided at a ratio of 1:2. That is, the other first center lug groove 43 and the other second center lug groove 44 are arranged in a smaller number in the circumferential direction of the tire than the other lug grooves 41, 45, and 46, two in number. In addition, in the pneumatic tire 1 of the embodiment, the one center lug groove 42 is arranged in a smaller number in the circumferential direction of the tire than the other lug grooves 41, 45, and 46, and are provided at a ratio of 1:2. That is, the one center lug groove 42 is arranged in a smaller number in the circumferential direction of the tire than the other lug grooves 41, 45, and 46, two in number.

[0079] According to the pneumatic tire 1 of the embodiment, the rigidity of the other center land portion 21B and the one center land portion 21A can be sufficiently ensured, and it is possible to improve the snow and ice performance and the wear resistance.

[0080] In the pneumatic tire 1 of the embodiment, the maximum dimension L3 in the tire width direction of the other center land portion 21B and the maximum dimension L4 in the tire width direction of the other middle land portion 22B satisfy the relationship 0.55≦L3 / L4≦0.65.

[0081] In the pneumatic tire 1 of the embodiment, when L3 / L4 is less than 0.55, the rigidity of the other center land portion 21B tends to be low and the effect of improving wear resistance tends to be reduced, and when it exceeds 0.65, the rigidity of the other middle land portion 22B tends to be low and the effect of improving performance on ice tends to be reduced, so the above range is set. In the pneumatic tire 1 of the embodiment, satisfying the relationship 0.55≦L3 / L4≦0.65 is preferable because it significantly improves wear resistance while ensuring snow and ice performance.

[0082] In addition, in the pneumatic tire 1 of the embodiment, the area ratio difference between one center small land portion 21AA defined by one center lug groove 42 and center connecting sipe 52 in one center land portion 21A and the other center small land portion 21BA defined by the other first center lug groove 43 in the other center land portion 21B is within ±20%.

[0083] According to the embodiment of the pneumatic tire 1, by keeping the area ratio difference between one center land portion 21AA and the other center land portion 21BA in the center portion within 20%, the difference in rigidity between them can be reduced and the occurrence of uneven wear can be suppressed.

[0084] In addition, in the pneumatic tire 1 of the embodiment, the maximum length La of one middle lug groove 41 in the tire width direction and the maximum dimension L1 of one middle land portion 22A in the tire width direction satisfy the relationship 0.50≦La / L1≦0.90, and the maximum length Lb of one center lug groove 42 in the tire width direction and the maximum dimension L2 of one center land portion 21A in the tire width direction satisfy the relationship 0.55≦Lb / L2≦0.95.

[0085] In the pneumatic tire 1 of the embodiment, when La / L1 is less than 0.50, wear resistance improves but snow performance tends to deteriorate, while when it exceeds 0.90, snow performance improves but wear resistance tends to deteriorate, so the above range is set. In the pneumatic tire 1 of the embodiment, satisfying the relationship 0.50≦La / L1≦0.90 is preferable because it significantly improves wear resistance while maintaining snow and ice performance. In addition, in the pneumatic tire 1 of the embodiment, when Lb / L2 is less than 0.55, wear resistance also improves but snow performance tends to deteriorate, while when it exceeds 0.95, snow performance also improves but wear resistance tends to deteriorate, so the above range is set. In the pneumatic tire 1 of the embodiment, satisfying the relationship 0.55≦Lb / L2≦0.95 is preferable because it significantly improves wear resistance while maintaining snow and ice performance.

[0086] In addition, in the pneumatic tire 1 of the embodiment, the maximum length Lc of the other second center lug groove 44 in the tire width direction and the maximum dimension L3 of the other center land portion 21B in the tire width direction satisfy the relationship 0.30≦Lc / L3≦0.50, the maximum length Ld of the other first middle lug groove 45 in the tire width direction and the maximum dimension L4 of the other middle land portion 22B in the tire width direction satisfy the relationship 0.30≦Ld / L4≦0.70, and the maximum length Le of the other second middle lug groove 46 in the tire width direction and the maximum dimension L4 of the other middle land portion 22B in the tire width direction satisfy the relationship 0.10≦Le / L4≦0.50.

[0087] In the pneumatic tire 1 of the embodiment, when Lc / L3 is less than 0.30, ice performance tends to improve but snow performance tends to deteriorate, and when it exceeds 0.50, snow performance tends to improve but ice performance tends to deteriorate, so the above range is set. In the pneumatic tire 1 of the embodiment, satisfying the relationship 0.30≦Lc / L3≦0.50 is preferable because it significantly improves the effect of ensuring snow and ice performance. In addition, in the pneumatic tire 1 of the embodiment, when Ld / L4 is less than 0.30, ice performance similarly improves but snow performance tends to deteriorate, and when it exceeds 0.70, snow performance similarly improves but ice performance tends to deteriorate, so the above range is set. In the pneumatic tire 1 of the embodiment, satisfying the relationship 0.30≦Ld / L4≦0.70 is preferable because it significantly improves the effect of ensuring snow and ice performance. Furthermore, in the pneumatic tire 1 of the embodiment, when Ld / L5 is less than 0.10, the on-ice performance also improves but the on-snow performance tends to deteriorate, and when it exceeds 0.50, the on-snow performance also improves but the on-ice performance tends to deteriorate, so the above range is set. In the pneumatic tire 1 of the embodiment, satisfying the relationship 0.10≦Le / L4≦0.50 is preferable because it significantly improves the snow and ice performance.

[0088] In addition, in the pneumatic tire 1 of the embodiment, the angle θ1 of one middle lug groove 41 relative to the tire width direction is in the range of 10°≦θ1≦40° in absolute value, the angle θ2 of one center lug groove 42 relative to the tire width direction is in the range of 10°≦θ2≦40° in absolute value, the angle θ3 of the other first center lug groove 43 relative to the tire width direction is in the range of 5°≦θ3≦35° in absolute value, and the angle θ4 of the other second middle lug groove 46 relative to the tire width direction is in the range of 1°≦θ4≦20° in absolute value.

[0089] In the pneumatic tire 1 of the embodiment, when the angle θ1 is less than 10°, the snow traction index component in the 0° direction increases, which encourages the collapse of one of the middle land portions 22A during braking, tending to deteriorate ice performance. When the angle θ1 exceeds 40°, the rigidity of one of the middle land portions 22A decreases, tending to deteriorate wear resistance. Therefore, the above range is set. In the pneumatic tire 1 of the embodiment, satisfying the relationship 10°≦θ1≦40° is preferable because it significantly improves wear resistance while ensuring snow and ice performance. Furthermore, in the pneumatic tire 1 of the embodiment, when the angle θ2 is less than 10°, the snow traction index component in the 0° direction increases, which encourages the collapse of one of the center land portions 21A during braking, tending to deteriorate ice performance. When the angle θ2 exceeds 40°, the rigidity of the center land portion 21 decreases, tending to deteriorate wear resistance. Therefore, the above range is set. In the pneumatic tire 1 of the embodiment, satisfying the relationship 10°≦θ2≦40° is preferable because it significantly improves wear resistance while ensuring snow and ice performance. Furthermore, in the pneumatic tire 1 of the embodiment, when the angle θ3 is less than 5°, the snow traction index component in the 0° direction increases, which encourages the other center land portion 21B to collapse during braking, tending to deteriorate ice performance. When the angle θ3 exceeds 35°, the rigidity of the other center land portion 21B decreases, tending to deteriorate wear resistance. Therefore, the above range is set. In the pneumatic tire 1 of the embodiment, satisfying the relationship 5°≦θ3≦35° is preferable because it significantly improves wear resistance while ensuring snow and ice performance. Furthermore, in the pneumatic tire 1 of the embodiment, when the angle θ4 is less than 1°, the snow traction index component in the 0° direction increases, which encourages the other middle land portion 22B to collapse during braking, tending to deteriorate ice performance, while when the angle θ4 exceeds 20°, the rigidity of the other middle land portion 22B decreases, tending to deteriorate wear resistance, so the above range is set. In the pneumatic tire 1 of the embodiment, satisfying the relationship 5°≦θ4≦20° is preferable because it significantly improves wear resistance while ensuring snow and ice performance.

[0090] The snow traction index in the 0° direction is an empirical formula proposed by Uniroyal at the SAE (Society of Automotive Engineers) and is defined by the following formula (1): In this formula, ρg is the groove density [1 / mm], and is the ratio [mm] of the groove length of all grooves (all grooves excluding sipes) projected in the circumferential direction of the tire on the tread contact surface to the tread contact area (the product of the tire contact width and tire circumference) [mm 2 ]. ρs is the sipe density [1 / mm], and is calculated as the ratio of the sipe length [mm] of all sipes projected in the circumferential direction of the tire on the tread contact surface to the tread contact area [mm 2 Dg is the average value of the groove depth [mm] of all grooves projected in the circumferential direction of the tire on the tread contact surface.

[0091] STI=-6.8+2202×ρg+672×ρs+7.6×Dg (1)

[0092] Furthermore, in the pneumatic tire 1 of the embodiment, the groove depth D1 of one middle lug groove 41 and the groove depth D of one shoulder circumferential groove 32A satisfy the relationship of 0.6≦D1 / D≦1.0, the groove depth D2 of one center lug groove 42 and the groove depth D of one middle circumferential groove 31A satisfy the relationship of 0.6≦D2 / D≦1.0, the groove depth D3 of the other first center lug groove 43 and the groove depth D of the center circumferential groove 30 satisfy the relationship of 0.6≦D3 / D≦1.0, the groove depth D4 of the other first middle lug groove 45 and the groove depth D of the other middle circumferential groove 31B satisfy the relationship of 0.6≦D4 / D≦1.0, and the groove depth D5 of the other second middle lug groove 46 and the groove depth D of the other shoulder circumferential groove 32B satisfy the relationship of 0.6≦D5 / D≦1.0.

[0093] According to the pneumatic tire 1 of the embodiment, when D1 / D, D2 / D, D3 / D, D4 / D, and D5 / D are less than 0.6, the wear resistance performance improves, but the snow performance tends to deteriorate. When it exceeds 1.0, the snow performance improves, but the rigidity of the land portions 22A, 21A, 21B, and 22B decreases and the wear resistance performance tends to decrease. Therefore, it is set within the above range.

[0094] Further, in the pneumatic tire 1 of the embodiment, the groove width W1 of one middle lug groove 41, the groove width W2 of one center lug groove 42, the groove width W3 of the other first center lug groove 43, the groove width W4 of the other first middle lug groove 45, and the groove width W5 of the other second middle lug groove 46 are in the range of 1.5 [mm] or more and 7.0 [mm] or less.

[0095] According to the pneumatic tire 1 of the embodiment, when the groove widths W1, W2, W3, W4, and W5 of the respective lug grooves 41, 42, 43, 45, and 46 are less than 1.5 [mm], the wear resistance performance improves, but the snow performance tends to deteriorate. When it exceeds 7.0 [mm], the snow performance improves, but the rigidity of the land portions 22A, 21A, 21B, and 22B decreases and the wear resistance performance tends to decrease. Therefore, it is set within the above range.

[0096] Further, in the pneumatic tire 1 of the embodiment, the direction with respect to the vehicle width direction when mounted on the vehicle is specified, one is the outer side in the vehicle width direction, and the other is the inner side in the vehicle width direction.

[0097] According to the pneumatic tire 1 of the embodiment, since the lug grooves 41 and 42 have the base ends 41a and 42a on the outer side in the vehicle width direction, drainage and snow removal are directed toward the outer circumferential grooves 32A and 31A during turning, so the performance on ice and snow improves.

[0098] Further, in the pneumatic tire 1 of the embodiment, on the tread contact surface 2B, the groove area ratio Go on the outer side in the vehicle width direction and the groove area ratio Gi on the inner side in the vehicle width direction with respect to the tire equatorial plane CL satisfy the relationship Gi < Go and 1.1 ≤ Go / Gi ≤ 1.3.

[0099] Here, the groove area ratio is defined as the percentage of groove area / (groove area + ground contact area). The groove area is the sum of the opening areas of the grooves in the tire ground contact surface. The ground contact area is measured between the grounding ends with reference to the plane where the pneumatic tire 1 contacts the flat plate when the pneumatic tire 1 with air is mounted on a normal rim, filled with the normal internal pressure, placed perpendicular to the flat plate in a stationary state, and a load corresponding to the normal load is applied. The groove area does not include the sipe.

[0100] According to the pneumatic tire 1 of the embodiment, by setting the groove area ratio as Gi < Go, the snow performance can be improved on the outer side in the vehicle width direction, and the ice performance can be improved on the inner side in the vehicle width direction by increasing the ground contact area, making it possible to achieve both ice and snow performance at a high level. And according to the pneumatic tire 1 of the embodiment, when Go / Gi is less than 1.1, the ice performance improves, but the snow performance tends to deteriorate. When it exceeds 1.3, the snow performance improves, but the ice performance tends to deteriorate. Therefore, the above range is set. Also, according to the pneumatic tire 1 of the embodiment, by satisfying the relationship of 1.1 ≦ Go / Gi ≦ 1.3, the effect of ensuring ice and snow performance can be significantly obtained, which is preferable.

[0101] In addition, the pneumatic tire 1 of the embodiment is applied to a studless tire that ensures driving performance on ice and snow roads or an all-season tire that ensures driving performance in winter by arranging the sipe 61 on the land portion 20.

[0102] In the pneumatic tire 1 of the embodiment, the sipe 61 is arranged along the extending direction of each of the lug grooves 41, 42, 43, 44, 45, 46 provided in each land portion 20.

[0103] According to the pneumatic tire 1 of the embodiment, since the length of the sipe 61 can be made long, the edge amount is large and the ice and snow performance is improved.

[0104] In addition, the pneumatic tire 1 of the embodiment has a snow traction index in the 0[°] direction of 100 or more.

[0105] According to this pneumatic tire 1, by making the snow traction index in the 0° direction 100 or more, improved performance on snow can be ensured, and the tire is applicable to studless tires or all-season tires.

[0106] In the pneumatic tire 1 of the embodiment, the tread portion 2 has a tread rubber (cap rubber) 2A with a hardness in the range of 40 or more and 70 or less.

[0107] The hardness is rubber hardness indicated by JIS-A hardness in accordance with JIS-K6253 under the condition of 20°C.

[0108] According to this pneumatic tire 1, by setting the hardness of the tread rubber 2A in the range of 40 or more and 70 or less, the rigidity of the land portion 20 can be ensured and performance on snow can be further improved. Note that, in the pneumatic tire 1 of the embodiment, when the hardness of the tread rubber 2A is in the range of 40 or more and 55 or less, it is suitable for a studless tire, and when the hardness of the tread rubber 2A is in the range of 55 or more and 70 or less, it is suitable for an all-season tire.

[0109] [Embodiment 2] A pneumatic tire 101 of embodiment 2 is shown in Figures 5 to 14. The pneumatic tire 101 of embodiment 2 has sipes 62, 63 in the pneumatic tire 1 of embodiment 1, but has the same other configuration. Therefore, the pneumatic tire 101 can be said to be another form of the pneumatic tire 1, and the same parts as those of the pneumatic tire 1 will be assigned the same reference numerals and will not be described again.

[0110] As described above, the land portion 20 has the sipes 61. The pneumatic tire 101 further has sipes 62, 63 in the outer middle land portion 22A and the outer center land portion 21A. Therefore, the pneumatic tire 101 has two or more types of sipes 62, 63 with different widths in the outer middle land portion 22A and the outer center land portion 21A.

[0111] The sipe 62 has the widest width Ws of all the sipes in the outer middle land portion 22A and is also referred to as a wide sipe. The sipe 62 has a width Ws of 0.5 mm to 1.5 mm (see FIG. 6) and a depth Ds of 2.0 mm to 10.0 mm (see FIG. 7). The sipe 62 is disposed adjacent to at least one of the lug grooves 41 adjacent to each other in the tire circumferential direction. "Adjacent" here means immediately adjacent, meaning that no other grooves or sipes exist between them. As shown in FIG. 6, one end 62a of the sipe 62 communicates with the outer shoulder circumferential groove 32A, which communicates with the lug groove 41, and the other end 62b terminates at the outer middle land portion 22A. Alternatively, the sipe 62 may have both ends 62a and 62b terminate at the outer middle land portion 22A (see FIG. 13).

[0112] The sipe 63 has the widest width Ws of all the sipes in the outer center land portion 21A and is also referred to as a wide sipe. The sipe 63 has a width Ws of 0.5 mm to 1.5 mm, as shown in FIG. 7, and a depth Ds of 2.0 mm to 10.0 mm, as shown in FIG. 7. The sipe 63 is disposed adjacent to at least one of the lug grooves 42 adjacent to each other in the tire circumferential direction. As shown in FIG. 5, one end 63a of the sipe 63 communicates with the outer middle circumferential groove 31A, which communicates with the lug groove 42, and the other end 63b terminates at the outer center land portion 21A. Although not shown in the figure, the sipe 63 may have both ends 63a and 63b terminate at the outer center land portion 21A, similar to the sipe 62.

[0113] The sipes 62, 63 have shapes that include a straight shape, a curved shape, or a zigzag shape on the tread contact surface 2B. The sipes 62, 63 have shapes that include a straight shape or a concave-convex shape in the depth direction or extension direction inside the tread rubber 2A. In this embodiment, the sipes 62, 63 are formed in a straight shape on the tread contact surface 2B and inside the tread rubber 2A.

[0114] Furthermore, as shown in FIG. 14, the pneumatic tire 101 may have narrow grooves 81 in the tread contact surface 2B. The narrow grooves 81 are formed to be narrower and shallower than the circumferential grooves, lug grooves, and sipes, for example, having a width of 0.4 mm or less and a depth of 0.3 mm or less. The narrow grooves 81 are arranged to extend in a direction intersecting the extension directions of the circumferential grooves, lug grooves, and sipes. The narrow grooves 81 may be connected to the circumferential grooves, lug grooves, and sipes, or may terminate at the tread contact surface 2B of the land portion 20 without being connected to the circumferential grooves, lug grooves, and sipes. Although the narrow grooves 81 are shown in a zigzag shape bending partway in FIG. 14, they may be formed to be straight or curved partway. 14 is provided in a form in which one end of the sipe 62 (63) communicates with the circumferential groove and the other end terminates in the land portion 20, but may also be provided in a form in which one end and the other end of the sipe 62 (63) terminate in the land portion 20 as shown in FIG. 13. Although not explicitly shown in the figure, the fine groove 81 may also be provided in the pneumatic tire 1.

[0115] The pneumatic tire 101 of the embodiment is characterized in that it has sipes that extend along the tire width direction and are arranged in multiple rows in the tire circumferential direction in each land portion 21A, 22A, 23A, 21B, 22B, 23B, and in one center land portion 21A, the sipes have two or more types of different widths and include a widest sipe 63 that is arranged adjacent to at least one of the center lug grooves 42 between each one of the center lug grooves 42, and in one middle land portion 22A, the sipes have two or more types of different widths and include a widest sipe 62 that is arranged adjacent to at least one of the middle lug grooves 41 between each one of the middle lug grooves 41.

[0116] In studless tires, the tread rubber 2A is a rubber with a relatively low hardness, so the lug grooves 41 (42) are easily crushed during braking and driving, which reduces the original functions of the lug grooves 41 (42), i.e., shear force in snow and drainage performance, and can result in a decrease in snow performance and wet performance. As shown in Figure 9, if a relatively narrow sipe 61 is placed adjacent to the lug groove 41 (42), the sipe 61 will be crushed first, which can cause the above-mentioned phenomenon.

[0117] In this regard, according to the pneumatic tire 101, by arranging the wide sipes 62(63) adjacent to the lug grooves 41(42), as shown in Fig. 8, the wide sipes 62(63) intentionally become locations that are easily crushed during braking / driving and function to prevent the lug grooves 41(42) from being crushed, thereby improving the shear force in snow and drainage performance of the lug grooves 41(42), and thereby improving performance on snow and wet conditions. In other words, the wide sipes 62(63) are wider than the other sipes 61, and therefore have a large range until they close and crush during braking / driving, and by suppressing deformation around them, they function to prevent the lug grooves 41(42) from being crushed.

[0118] Furthermore, in the pneumatic tire 1 of the embodiment, if all the sipes in the land portion 20 were wide sipes 62 (63), the ground contact area would be reduced, the adhesive friction force would decrease, and performance on ice would be degraded, and the rigidity of the land portion 20 would also be reduced, degrading wear resistance. For this reason, the pneumatic tire 101 of the embodiment has two or more types of sipes with different widths, thereby ensuring performance on ice.

[0119] As a result, the pneumatic tire 101 can improve its performance on snow and wet surfaces without impairing its performance on ice.

[0120] In the embodiment of the pneumatic tire 101, the wide sipes 62 (63) are arranged adjacent to only one side of the lug groove 41 (42) in the tire circumferential direction, but the wide sipes 62 (63) may also be arranged adjacent to the other side of the lug groove 41 (42) in the tire circumferential direction, and the same effect can be obtained.

[0121] In the pneumatic tire 101 of the embodiment, the width Ws of the wide sipe 62 (63) and the width Wsa of the other sipes 61 satisfy the relationship 1.1≦Ws / Wsa≦4.0.

[0122] In this pneumatic tire 101, if Ws / Wsa is less than 1.1, it becomes difficult to obtain the effect of preventing the lug grooves 41 (42) from collapsing. Also, in this pneumatic tire 101, if Ws / Wsa exceeds 4.0, the rigidity of the land portions 20 decreases, making it difficult to obtain performance on ice. Therefore, by setting Ws / Wsa in the above range, this pneumatic tire 101 can significantly obtain the effect of improving performance on snow and wet ground without impairing performance on ice.

[0123] Furthermore, in the pneumatic tire 101 of the embodiment, the distance Bs between the adjacent lug grooves 41 (42) and the wide sipes 62 (63) is preferably in the range of 3.0 mm to 10.0 mm in order to achieve the above-described effects. In the pneumatic tire 101 of the embodiment, if the distance Bs is less than 3.0 mm, the tread rubber 2A between them becomes thin and tends to chip easily. In addition, in the pneumatic tire 101 of the embodiment, if the distance Bs exceeds 10.0 mm, the tread rubber 2A between them becomes thick, which tends to reduce the function of the wide sipes 62 (63) in preventing the lug grooves 41 (42) from being crushed, making it difficult to achieve the effect of improving snow performance and wet performance. Therefore, in the pneumatic tire 101, by setting the distance Bs between the lug grooves 41 (42) and the wide sipes 62 (63) in the above-described range, the effect of improving snow performance and wet performance can be significantly achieved and chipping of the land portion 20 can also be prevented.

[0124] The distance Bs between the lug groove 41 (42) and the wide sipe 62 (63) is the distance between the center lines of the lug groove 41 (42) and the wide sipe 62 (63). The center line is a straight line connecting the centers of both ends of the lug groove 41 (42) and the wide sipe 62 (63).

[0125] In addition, in the pneumatic tire 101 of the embodiment, the distance Bs between adjacent lug grooves 41 (42) and wide sipes 62 (63) and the groove width W1 (W2) of the lug groove 41 (42) satisfy the relationship 1.0≦Bs / W1≦3.0 (1.0≦Bs / W2≦3.0).

[0126] In this pneumatic tire 101, if Bs / W1 (Bs / W2) is less than 1.0, the rigidity of the land portion 20 decreases, and performance on ice tends to deteriorate. Also, in this pneumatic tire 101, if Bs / W1 (Bs / W2) is more than 3.0, the rigidity of the land portion 20 increases, and the ability to crush the sipes 62 (63) tends to decrease, making it difficult to achieve the effect of improving performance on snow and wet surfaces. Therefore, by setting Bs / W1 (Bs / W2) in the above range, this pneumatic tire 101 can significantly improve performance on snow and wet surfaces without impairing performance on ice.

[0127] In addition, in the pneumatic tire 101 of the embodiment, the groove depth D1 (D2) of the adjacent lug grooves 41 (42) and the depth Ds of the wide sipe 62 (63) satisfy the relationship 0.2≦Ds / D1≦1.0 (0.2≦Ds / D2≦1.0).

[0128] In this pneumatic tire 101, if Ds / D1 (Ds / D2) is less than 0.2, the rigidity of the land portions 20 increases, which tends to reduce the ability to crush the sipes 62 (63), making it difficult to achieve the effect of improving snow performance and wet performance. Also, in this pneumatic tire 101, if Ds / D1 (Ds / D2) exceeds 1.0, the rigidity of the land portions 20 decreases, which tends to reduce performance on ice. Therefore, by setting Ds / D1 (Ds / D2) in the above range, the pneumatic tire 101 can significantly improve snow performance and wet performance without compromising performance on ice.

[0129] In the pneumatic tire 101 of the embodiment, the length Lr of the lug groove 41 (42) and the length Ls of the wide sipe 62 (63) adjacent to each other satisfy the relationship 0.4≦Ls / Lr≦0.9.

[0130] In this pneumatic tire 101, if Ls / Lr is less than 0.4, the rigidity of the land portions 20 increases, which tends to reduce the ability to crush the sipes 43, making it difficult to achieve the effect of improving snow performance and wet performance. Also, in this pneumatic tire 101, if Ls / Lr exceeds 0.9, the rigidity of the land portions 20 decreases, which tends to reduce performance on ice. Therefore, by setting Ls / Lr in the above range, this pneumatic tire 101 can significantly achieve the effect of improving snow performance and wet performance without impairing performance on ice.

[0131] In the pneumatic tire 101 of the embodiment, the wide sipes 62 (63) are arranged to extend along the extending direction of the lug grooves 41 (42) adjacent to each other.

[0132] The adjacent lug grooves 41 (42) and wide sipes 62 (63) are inclined in the same direction relative to the tire width direction in their extension directions, and the difference in inclination angle between the adjacent lug grooves 41 (42) and wide sipes 62 (63) extending in the same direction (θs-θr: absolute value) is within a range of 10°. The adjacent lug grooves 41 (42) and wide sipes 62 (63) are preferably parallel to each other. This pneumatic tire 101 improves the crushing effect of the sipes 62 (63), making it easier to obtain the effect of improving snow performance and wet performance. Note that it is preferable that all of the lug grooves 41 (42) and wide sipes 62 (63) arranged in one land portion 20 are inclined in the same direction relative to the tire width direction.

[0133] In the pneumatic tire 101 of the embodiment, the tread portion 2 has a groove area ratio of the tread pattern in the range of 20% to 40%.

[0134] According to this pneumatic tire 101, by setting the groove area ratio of the tread pattern in the range of 20% to 40%, it is possible to obtain a significant effect of improving the performance on snow and wet conditions.

[0135] In the pneumatic tire 101 of the embodiment, the wide sipe 62 (63) has a depth Ds that is constant or gradually changes in the length direction, or has an upper bottom 62e (63e) on the bottom 62d (63d).

[0136] The depth Ds being constant in the length direction means that the depth Ds from the opening 62c (63c) to the bottom 62d (63d) does not change in the length direction (between one end 62a (63a) and the other end 62b (63b)) as shown in Fig. 10. Furthermore, the depth Ds gradually changing in the length direction means that the bottom 62d (63d) is inclined in the length direction (between one end 62a (63a) and the other end 62b (63b)) with respect to the length direction, so that the depth Ds of the wide sipe 62 (63) gradually changes, as shown in Fig. 11. Furthermore, the phrase "having an upper bottom portion 62e (63e) at the bottom portion 62d (63d) of the wide sipe 62 (63)" means that the bottom portion 62d (63d) has a portion where the depth Ds suddenly becomes shallower as the bottom portion 62d (63d) protrudes outward in the tire radial direction midway in the length direction (between one end 62a (63a) and the other end 62b (63b)), as shown in Fig. 12. The depth Ds of the upper bottom portion 62e (63e) may be constant or gradually change in the length direction.

[0137] According to the pneumatic tire 101, various bottom shapes of the wide sipes 62 (63) do not hinder the above-mentioned effects from being achieved. However, in order to significantly achieve the above-mentioned effects, it is preferable that the depth Ds of the pneumatic tire 101 is constant in the length direction, since this has a significant effect on the lug grooves 41.

[0138] In the present embodiment, as described above, a pneumatic tire 1 has been described as an example of a tire. The pneumatic tire 1 can be filled with air, an inert gas such as nitrogen, or other gases. However, the tread pattern configuration of the pneumatic tire 1 described in the present embodiment can be applied to other tires as desired within the scope of what is obvious to those skilled in the art. Examples of other tires include airless tires and solid tires. [Example]

[0139] 15 to 20 are tables showing the results of performance tests of pneumatic tires according to the embodiment. Performance evaluation tests conducted on a conventional pneumatic tire and an example pneumatic tire according to the embodiment will be described below. The performance evaluation tests were conducted on ice performance, snow performance, wear resistance, and wet performance.

[0140] The performance evaluation test was carried out by mounting a pneumatic tire 1 having a tire nominal size of 255 / 35R19 96Q as specified by JATMA on a JATMA standard rim wheel having a rim size of 19 x 9.0J, mounting the test tire on a four-wheel drive evaluation vehicle with an engine displacement of 2000cc, adjusting the air pressure to 250 kPa for the front wheels and 250 kPa for the rear wheels, and running the evaluation vehicle.

[0141] To evaluate ice performance, a test vehicle fitted with the test tires is subjected to a braking test on an icy test course, and the braking distance is measured. Based on the results of these tests, the reciprocal of the tire's braking distance is used to evaluate the tire's performance, with the conventional tire being used as the benchmark (100). The higher the evaluation value, the better.

[0142] The evaluation test for snow performance involves braking tests on a test vehicle fitted with test tires on a snowy test course, measuring the braking distance. Based on the results of these tests, the reciprocal of the tire's braking distance is used to evaluate the tire's performance, with the conventional tire being used as the standard (100). The higher the evaluation value, the better.

[0143] The wear resistance evaluation test involves measuring the amount of wear after a test vehicle fitted with a test tire has driven 10,000 km on a dry asphalt test course. Based on the results of this measurement, the reciprocal of the tire's wear is used to evaluate the tire's performance, with the conventional tire being used as the standard (100). The higher the evaluation value, the better.

[0144] For the wet performance evaluation test, a braking test from 100 [km / h] is conducted on a wet road surface test course with a water depth of 1 [mm] using an evaluation vehicle equipped with a test tire, and the braking distance is measured. Then, based on this measurement result, the reciprocal is subject to an index evaluation with the conventional example as the reference (100). In this evaluation, the larger the numerical value, the more favorable it is.

[0145] The conventional pneumatic tire has five straight circumferential grooves, an outer middle lug groove, an outer center lug groove, an inner first center lug groove, an inner second center lug groove, and an inner second middle lug groove. Except for the inner second center lug groove, the land portions are penetrated, and each lug groove is inclined in the same direction with respect to the tire width direction. Also, in the conventional pneumatic tire, the tire width direction dimensions of the inner center land portion and the inner middle land portion are the same. Further, in the conventional pneumatic tire, the total number in the tire circumferential direction of the inner first center lug groove and the inner second center lug groove is the same as that of the other lug grooves. Also, in the conventional pneumatic tire, the groove wall of the outer shoulder circumferential groove is not inclined.

[0146] As shown in FIG. 2, the pneumatic tire of the embodiment has five straight circumferential grooves, an outer middle lug groove, an outer center lug groove, an inner first center lug groove, an inner second center lug groove, an inner first middle lug groove, and an inner second middle lug groove. And in the pneumatic tire of the embodiment, the maximum dimension L3 in the tire width direction of the inner center land portion and the maximum dimension L4 in the tire width direction of the inner middle land portion satisfy the relationship of L3 < L4, and the outer middle lug groove, the outer center lug groove, the inner first center lug groove, the inner second center lug groove, the inner first middle lug groove, and the inner second middle lug groove are provided with inclined directions opposite to each other alternately with respect to the tire width direction. Each of the center lug grooves provided in the inner center land portion is provided with a smaller total number arranged in the tire circumferential direction with respect to the middle lug groove of the outer middle land portion and each middle lug groove of the inner middle land portion. The outer shoulder circumferential groove is formed such that each groove wall between a plurality of outer middle lug grooves is inclined in the same direction with respect to the tire circumferential direction, and the other circumferential grooves are formed in a straight line along the tire circumferential direction of the groove wall.

[0147] As shown in the test results, the pneumatic tire of this example has improved ice performance, snow performance, wear resistance, and wet performance compared to the conventional tire.

[0148] The present disclosure includes the following inventions. [Invention 1] One center circumferential groove formed linearly along the tire circumferential direction and disposed closest to the tire equatorial plane; one middle circumferential groove and the other middle circumferential groove are formed linearly along the tire circumferential direction and are arranged on either side of the center circumferential groove; one shoulder circumferential groove and the other shoulder circumferential groove are formed linearly along the tire circumferential direction and are defined on the tire width direction outer sides of each of the middle circumferential grooves; one center land portion defined between the center circumferential groove and one of the middle circumferential grooves; another center land portion defined between the center circumferential groove and the other middle circumferential groove; a middle land portion defined between the one middle circumferential groove and the one shoulder circumferential groove; another middle land portion defined between the other middle circumferential groove and the other shoulder circumferential groove; one shoulder land portion defined on the outer side in the tire width direction of the one shoulder circumferential groove; another shoulder land portion defined on the outer side in the tire width direction of the other shoulder circumferential groove; one middle lug groove, which is arranged in a row in the tire circumferential direction in the one middle land portion, and whose base ends extending along the tire width direction communicate with the one shoulder circumferential groove and whose tip ends terminate inside the one middle land portion; one center lug groove, which is arranged in a row in the tire circumferential direction in the one center land portion, and whose base end extending along the tire width direction in the one center land portion communicates with the one middle circumferential groove and whose tip end terminates inside the one center land portion; On the other center land portion, a plurality of other first center lug grooves are provided side by side in the tire circumferential direction, each having a base end extending along the tire width direction and communicating with the center circumferential groove, and a tip end penetrating through the other center land portion and communicating with the other middle circumferential groove. On the other center land portion, a plurality of other second center lug grooves are provided side by side in the tire circumferential direction, each having a base end extending along the tire width direction and communicating with the other middle circumferential groove, and a tip end terminating inside the other center land portion, and being alternately arranged with the other first center lug grooves in the tire circumferential direction. On the other middle land portion, a plurality of other first middle lug grooves are provided side by side in the tire circumferential direction, each having a base end extending along the tire width direction and communicating with the other middle circumferential groove, and a tip end terminating inside the other middle land portion. On the other middle land portion, a plurality of other second middle lug grooves are provided side by side in the tire circumferential direction, each having a base end extending along the tire width direction and communicating with the other shoulder circumferential groove, and a tip end terminating inside the other middle land portion. On the one shoulder land portion, a plurality of one shoulder lug grooves are provided side by side in the tire circumferential direction, each having a base end extending along the tire width direction and communicating with the one shoulder circumferential groove, and a tip end side reaching the grounding end. On the other shoulder land portion, a plurality of other shoulder lug grooves are provided side by side in the tire circumferential direction, each having a base end extending along the tire width direction and communicating with the other shoulder circumferential groove, and a tip end side reaching the grounding end. On the one middle land portion, a middle communication sipe extends from the tip end of the one shoulder lug groove and communicates with the one middle circumferential groove. On the one center land portion, a center communication sipe extends from the tip end of the one center lug groove and communicates with the center circumferential groove. The tread portion has the above. The maximum dimension L3 in the tire width direction of the other center land portion and the maximum dimension L4 in the tire width direction of the other middle land portion satisfy the relationship L3 < L4. the one middle lug groove, the one center lug groove, the other first center lug groove, the other second center lug groove, the other first middle lug groove, and the other second middle lug groove are alternately provided in opposite inclination directions with respect to the tire width direction, the center lug grooves provided in the other center land portion are arranged in a smaller number in the tire circumferential direction than the middle lug grooves of the one middle land portion and the middle lug grooves of the other middle land portion, In the one shoulder circumferential groove, groove walls between the plurality of one middle lug grooves are formed so as to be inclined in the same direction with respect to the tire circumferential direction, and in the other circumferential groove, groove walls are formed so as to be linear along the tire circumferential direction. tire. [Invention 2] a maximum dimension L3 of the other center land portion in the tire width direction and a maximum dimension L4 of the other middle land portion in the tire width direction satisfy the relationship 0.55≦L3 / L4≦0.65; A tire according to claim 1. [Invention 3] an area ratio difference between one center small land portion defined by the one center lug groove and the center connecting sipe in the one center land portion and the other center small land portion defined by the other first center lug groove in the other center land portion is within ±20%; The tire according to claim 1 or 2. [Invention 4] a maximum length La of the one middle lug groove in the tire width direction and a maximum dimension L1 of the one middle land portion in the tire width direction satisfy the relationship 0.50≦La / L1≦0.90; The maximum length Lb of the one center lug groove in the tire width direction and the maximum dimension L2 of the one center land portion in the tire width direction satisfy the relationship of 0.55≦Lb / L2≦0.95. A tire according to any one of inventions 1 to 3. [Invention 5] the maximum length Lc of the other second center lug groove in the tire width direction and the maximum dimension L3 of the other center land portion in the tire width direction satisfy the relationship 0.30≦Lc / L3≦0.50, a maximum length Ld of the other first middle lug groove in the tire width direction and a maximum dimension L4 of the other middle land portion in the tire width direction satisfy the relationship 0.30≦Ld / L4≦0.70, a maximum length Le of the other second middle lug groove in the tire width direction and a maximum dimension L4 of the other middle land portion in the tire width direction satisfy the relationship 0.10≦Le / L4≦0.50; A tire according to any one of inventions 1 to 4. [Invention 6] The angle θ1 of the one middle lug groove with respect to the tire width direction is in the range of 10 [°] ≦ θ1 ≦ 40 [°] in absolute value, The angle θ2 of the one center lug groove with respect to the tire width direction is in the range of 10 [°] ≦ θ2 ≦ 40 [°] in absolute value, The angle θ3 of the other first center lug groove with respect to the tire width direction is in the range of 5 [°] ≦ θ3 ≦ 35 [°] in absolute value, The angle θ4 of the other second middle lug groove with respect to the tire width direction is in the range of 1 [°]≦θ4≦20 [°] in absolute value. A tire according to any one of inventions 1 to 5. [Invention 7] a groove depth D1 of the one middle lug groove and a groove depth D of the one shoulder circumferential groove satisfy a relationship of 0.6≦D1 / D≦1.0, a groove depth D2 of the one center lug groove and a groove depth D of the one middle circumferential groove satisfy the relationship 0.6≦D2 / D≦1.0, a groove depth D3 of the other first center lug groove and a groove depth D of the center circumferential groove satisfy the relationship 0.6≦D3 / D≦1.0, a groove depth D4 of the other first middle lug groove and a groove depth D of the other middle circumferential groove satisfy a relationship of 0.6≦D4 / D≦1.0, a groove depth D5 of the other second middle lug groove and a groove depth D of the other shoulder circumferential groove satisfy a relationship of 0.6≦D5 / D≦1.0; The tire according to any one of Inventions 1 to 6. [Invention 8] The groove width W1 of the one middle lug groove, the groove width W2 of the one center lug groove, the groove width W3 of the other first center lug groove, the groove width W4 of the other first middle lug groove, and the groove width W5 of the other second middle lug groove are in the range of 1.5 [mm] or more and 7.0 [mm] or less. The tire according to any one of Inventions 1 to 7. [Invention 9] The orientation with respect to the vehicle width direction when mounted on a vehicle is specified. One of them is on the outer side in the vehicle width direction, and the other is on the inner side in the vehicle width direction. The tire according to any one of Inventions 1 to 8. [Invention 10] On the tread contact surface, the groove area ratio Go on the outer side in the vehicle width direction with the tire equatorial plane as a boundary and the groove area ratio Gi on the inner side in the vehicle width direction satisfy the relationship Gi < Go and 1.1 ≦ Go / Gi ≦ 1.3. The tire according to Invention 9. [Invention 11] Each of the land portions has sipes that extend along the tire width direction and are arranged in a plurality in the tire circumferential direction. In the one center land portion, the sipes have two or more different widths and include the widest wide sipe that is arranged adjacent to at least one of the one center lug grooves between each of the one center lug grooves. In the one middle land portion, the sipes have two or more different widths and include the widest wide sipe that is arranged adjacent to at least one of the one middle lug grooves between each of the one middle lug grooves. The tire according to any one of Inventions 1 to 10. [Invention 12] The width Ws of the wide sipe and the width Wsa of the other sipe satisfy the relationship 1.1 ≦ Ws / Wsa ≦ 4.0. The tire according to Invention 11. [Invention 13] A groove depth Da of the lug groove between which the wide sipe is disposed and a depth Ds of the wide sipe adjacent to the lug groove satisfy the relationship of 0.2≦Ds / Da≦1.0. 13. The tire according to claim 11 or 12. [Invention 14] The length Lr of the lug groove between which the wide sipe is disposed and the length Ls of the wide sipe adjacent to the lug groove satisfy the relationship of 0.4≦Ls / Lr≦0.9. 14. A tire according to any one of claims 11 to 13. [Invention 15] The wide sipes are arranged to extend along the extension direction of the adjacent lug grooves. 15. A tire according to any one of claims 11 to 14. [Invention 16] The snow traction index in the 0° direction is 100 or higher. 16. A tire according to any one of claims 1 to 15. [Invention 17] The tread portion has a tread rubber hardness in the range of 40 or more and 70 or less. 17. A tire according to any one of claims 1 to 16. [Explanation of symbols]

[0149] 1,101 pneumatic tires 2 Tread section 2A Tread rubber 2B tread contact surface 21A Outer center land area (one center land area) 21B Inner center land area (other center land area) 22A Outer middle land area (one middle land area) 22B Inner middle land part (other middle land part) 23A Outer shoulder land area (one shoulder land area) 23B Inner shoulder land portion (other shoulder land portion) 30 Center circumferential groove 31A Outer middle circumferential groove (one of the middle circumferential grooves) 31B Inner middle circumferential groove (other middle circumferential groove) 32A Outer shoulder circumferential groove (one shoulder circumferential groove) 32Aa Groove wall 32B Inner shoulder circumferential groove (other shoulder circumferential groove) 41 Outer middle lug groove (one middle lug groove) 42 Outer center lug groove (one of the center lug grooves) 43 Inner first center lug groove (other first center lug groove) 44 Inner second center lug groove (other second center lug groove) 45 Inner first middle lug groove (other first middle lug groove) 46 Inner second middle lug groove (other second middle lug groove) 47 Outer shoulder lug groove (one shoulder lug groove) 48 Inner shoulder lug groove (other shoulder lug groove) 51 Middle connecting sipes 52 Center connecting sipe 61 Sipe 62,63 wide sipes

Claims

1. one center circumferential groove formed linearly along the tire circumferential direction and disposed closest to the tire equatorial plane; one middle circumferential groove and the other middle circumferential groove are formed linearly along the tire circumferential direction and are arranged on either side of the center circumferential groove; one shoulder circumferential groove and the other shoulder circumferential groove are formed linearly along the tire circumferential direction and are defined on the tire width direction outer sides of each of the middle circumferential grooves; one center land portion defined between the center circumferential groove and one of the middle circumferential grooves; another center land portion defined between the center circumferential groove and the other middle circumferential groove; a middle land portion defined between the one middle circumferential groove and the one shoulder circumferential groove; another middle land portion defined between the other middle circumferential groove and the other shoulder circumferential groove; one shoulder land portion defined on the outer side in the tire width direction of the one shoulder circumferential groove; another shoulder land portion defined on the outer side in the tire width direction of the other shoulder circumferential groove; one middle lug groove, which is arranged in a row in the tire circumferential direction in the one middle land portion, and whose base ends extending along the tire width direction communicate with the one shoulder circumferential groove and whose tip ends terminate inside the one middle land portion; one center lug groove, which is arranged in a row in the tire circumferential direction in the one center land portion, and whose base end extending along the tire width direction communicates with the one middle circumferential groove and whose tip end terminates inside the one center land portion; a plurality of other first center lug grooves arranged side by side in the tire circumferential direction in the other center land portion, the base ends of the other first center lug grooves extending along the tire width direction being connected to the center circumferential groove and the tip ends of the other first center lug grooves penetrating the other center land portion and connecting to the other middle circumferential groove; a plurality of second center lug grooves arranged side by side in the tire circumferential direction in the other center land portion, the base ends of the second center lug grooves extending along the tire width direction in the other center land portion communicating with the other middle circumferential groove and the tip ends terminating inside the other center land portion, the second center lug grooves being arranged alternately with the first center lug grooves in the tire circumferential direction; a plurality of other first middle lug grooves arranged side by side in the tire circumferential direction in the other middle land portion, the base ends of the other first middle lug grooves extending along the tire width direction being connected to the other middle circumferential groove and the tip ends being terminated inside the other middle land portion; a second middle lug groove, the second middle lug groove being arranged in a row in the tire circumferential direction in the other middle land portion, the second middle lug groove having a base end extending along the tire width direction in the other middle land portion and communicating with the other shoulder circumferential groove and a tip end terminating inside the other middle land portion; one shoulder lug groove, a plurality of which are arranged in the tire circumferential direction in the one shoulder land portion, with base ends extending along the tire width direction communicating with the one shoulder circumferential groove and tip ends reaching the ground contact edge; a plurality of other shoulder lug grooves arranged side by side in the tire circumferential direction in the other shoulder land portion, each having a base end extending along the tire width direction and communicating with the other shoulder circumferential groove and a tip end reaching the ground contact edge; a middle connecting sipe extending from a tip end of the one middle lug groove in the one middle land portion and communicating with the one middle circumferential groove; a center communicating sipe extending from a tip end of the one center lug groove in the one center land portion and communicating with the center circumferential groove; in the tread portion, a maximum dimension L3 of the other center land portion in the tire width direction and a maximum dimension L4 of the other middle land portion in the tire width direction satisfy the relationship L3<L4; the one middle lug groove, the one center lug groove, the other first center lug groove, the other second center lug groove, the other first middle lug groove, and the other second middle lug groove are alternately provided in opposite inclination directions with respect to the tire width direction, the center lug grooves provided in the other center land portion are arranged in a smaller number in the tire circumferential direction than the middle lug grooves of the one middle land portion and the middle lug grooves of the other middle land portion, In the one shoulder circumferential groove, groove walls between the plurality of one middle lug grooves are formed so as to be inclined in the same direction with respect to the tire circumferential direction, and in the other circumferential groove, groove walls are formed so as to be linear along the tire circumferential direction. tire.

2. a maximum dimension L3 of the other center land portion in the tire width direction and a maximum dimension L4 of the other middle land portion in the tire width direction satisfy a relationship of 0.55≦L3 / L4≦0.65; 2. The tire of claim 1.

3. a difference in area ratio between one center small land portion defined by the one center lug groove and the center connecting sipe in the one center land portion and the other center small land portion defined by the other first center lug groove in the other center land portion is within ±20%; 2. The tire of claim 1.

4. a maximum length La of the one middle lug groove in the tire width direction and a maximum dimension L1 of the one middle land portion in the tire width direction satisfy the relationship 0.50≦La / L1≦0.90, a maximum length Lb of the one center lug groove in the tire width direction and a maximum dimension L2 of the one center land portion in the tire width direction satisfy a relationship of 0.55≦Lb / L2≦0.95; 2. The tire of claim 1.

5. a maximum length Lc of the other second center lug groove in the tire width direction and a maximum dimension L3 of the other center land portion in the tire width direction satisfy the relationship 0.30≦Lc / L3≦0.50, a maximum length Ld of the other first middle lug groove in the tire width direction and a maximum dimension L4 of the other middle land portion in the tire width direction satisfy the relationship 0.30≦Ld / L4≦0.70, a maximum length Le of the other second middle lug groove in the tire width direction and a maximum dimension L4 of the other middle land portion in the tire width direction satisfy a relationship of 0.10≦Le / L4≦0.50; 2. The tire of claim 1.

6. the angle θ1 of the one middle lug groove with respect to the tire width direction is in the range of 10°≦θ1≦40° in absolute value, the angle θ2 of the one center lug groove with respect to the tire width direction is in the range of 10°≦θ2≦40° in absolute value, the angle θ3 of the other first center lug groove with respect to the tire width direction is in the range of 5°≦θ3≦35° in absolute value, the angle θ4 of the other second middle lug groove with respect to the tire width direction is in the range of 1°≦θ4≦20° in absolute value; 2. The tire of claim 1.

7. a groove depth D1 of the one middle lug groove and a groove depth D of the one shoulder circumferential groove satisfy a relationship of 0.6≦D1 / D≦1.0, a groove depth D2 of the one center lug groove and a groove depth D of the one middle circumferential groove satisfy a relationship of 0.6≦D2 / D≦1.0, a groove depth D3 of the other first center lug groove and a groove depth D of the center circumferential groove satisfy the relationship 0.6≦D3 / D≦1.0, a groove depth D4 of the other first middle lug groove and a groove depth D of the other middle circumferential groove satisfy a relationship of 0.6≦D4 / D≦1.0, a groove depth D5 of the other second middle lug groove and a groove depth D of the other shoulder circumferential groove satisfy a relationship of 0.6≦D5 / D≦1.0; 2. The tire of claim 1.

8. a groove width W1 of the one middle lug groove, a groove width W2 of the one center lug groove, a groove width W3 of the other first center lug groove, a groove width W4 of the other first middle lug groove, and a groove width W5 of the other second middle lug groove are in the range of 1.5 mm or more and 7.0 mm or less; 2. The tire of claim 1.

9. The direction relative to the vehicle width when installed is specified. The one is on the outer side in the vehicle width direction, and the other is on the inner side in the vehicle width direction.

2. The tire of claim 1.

10. In the tread contact surface, a groove area ratio Go on the outer side in the vehicle width direction and a groove area ratio Gi on the inner side in the vehicle width direction with respect to the tire equatorial plane satisfy the relationship Gi<Go and 1.1≦Go / Gi≦1.

3.

10. The tire of claim 9.

11. Each land portion has a plurality of sipes extending along the tire width direction and arranged side by side in the tire circumferential direction, In the one center land portion, the sipes have two or more types of widths different from each other, and include a wide sipe having the widest width that is disposed adjacent to at least one of the one center lug grooves between the one center lug grooves, In the one middle land portion, the sipes have two or more types of different widths, and include a wide sipe having the widest width and disposed adjacent to at least one of the one middle lug grooves between the one middle lug grooves.

2. The tire of claim 1.

12. a width Ws of the wide sipe and a width Wsa of the other sipes satisfy the relationship 1.1≦Ws / Wsa≦4.0; 12. The tire of claim 11.

13. A groove depth Da of the lug groove between which the wide sipe is disposed and a depth Ds of the wide sipe adjacent to the lug groove satisfy a relationship of 0.2≦Ds / Da≦1.

0.

12. The tire of claim 11.

14. The length Lr of the lug groove between which the wide sipe is disposed and the length Ls of the wide sipe adjacent to the lug groove satisfy the relationship of 0.4≦Ls / Lr≦0.

9.

12. The tire of claim 11.

15. The wide sipes are arranged to extend along the extension direction of the adjacent lug grooves.

12. The tire of claim 11.

16. The snow traction index in the 0° direction is 100 or more.

2. The tire of claim 1.

17. The tread portion has a tread rubber hardness in the range of 40 or more and 70 or less.

2. The tire of claim 1.

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