tire

Abstract

To provide a tire excellent in snow performance, wet performance, and dry performance.SOLUTION: In an outer land part 20, an inclined groove 50, an inclined narrow groove 52, a reverse inclined groove 54, and a circumferential narrow groove 88 are arranged. The inclined groove 50 extends outward in a tire width direction from a circumferential main groove 16, is inclined from a step-in side to a kick-out side, and has a tip connected to a tread end T. The inclined narrow groove 52 extends outward in the tire width direction from the circumferential main groove 16, is inclined from the step-in side to the kick-out side, and has a tip arranged in the outer land part 20. The reverse inclined groove 54 extends from the kick-out side toward the step-in side, and is inclined from an inner side to an outer side in the tire width direction. The circumferential narrow groove 88 is arranged in a range of 5% or more and 15% or less of a tire width direction length Wh from a tire equatorial plane CP to a ground contact end, inward in the tire width direction from the ground contact end.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Winter tires with improved braking performance on snowy roads are known. For example, Patent Document 1 discloses a tire in which a plurality of block rows are formed on the tread surface by at least two circumferential main grooves extending in the circumferential direction and a plurality of lateral grooves extending from both tread edges toward the tire centerline at an inclination in the radial direction, and each block has a plurality of sipes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-301508 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, winter tires have been required to have high levels of wet and dry performance in addition to performance on snowy roads.

[0005] An object of the present invention is to provide a tire that is excellent in snow performance, wet performance and dry performance. [Means for solving the problem]

[0006] A tire according to one aspect of the present invention includes: a circumferential main groove; an inner land portion defined by at least two of the circumferential main grooves; outer land portions disposed on the outer side in the tire width direction relative to the inner land portion, with the circumferential main groove interposed therebetween, The tire has an inclined groove, an inclined narrow groove, a reverse inclined groove, and a circumferential narrow groove, which are arranged in the outer land portion, the inclined groove extends from the circumferential main groove toward an outer side in the tire width direction, inclines from a leading side to a trailing side in the tire circumferential direction, and has a tip connected to a tread edge, the inclined narrow groove extends from the circumferential main groove toward the outer side in the tire width direction, inclines from the leading side to the trailing side in the tire circumferential direction, and has a tip located within the outer land portion, The reverse inclined groove extends from the trailing side to the leading side in the tire circumferential direction and is inclined from the inner side to the outer side in the tire width direction, The circumferential narrow grooves are arranged from the ground contact edge to the inner side in the tire width direction, covering a range of 5% to 15% of the tire width direction length from the tire equatorial plane to the ground contact edge. [Effects of the Invention]

[0007] The tire of the present invention is excellent in snow performance, wet performance and dry performance. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a partial plan view of a tire according to an embodiment of the present invention. [Figure 2] 1 is a partially enlarged plan view of a tire according to an embodiment of the present invention, centered on the tire equatorial plane. [Figure 3] FIG. 3 is a partially enlarged cross-sectional view taken along line III-III in FIG. 2. [Figure 4] 4 is an enlarged cross-sectional view of a portion j taken along line IV-IV in FIG. 2. FIG. [Figure 5] FIG. 3 is a partially enlarged cross-sectional view taken along line VV in FIG. 2. [Figure 6] 1 is a partially enlarged plan view of one side in the tire width direction from the tire equatorial plane of a tire according to an embodiment of the present invention. FIG. [Figure 7] FIG. 7 is a partially enlarged cross-sectional view taken along line VII-VII in FIG. 6. [Figure 8] FIG. 8 is a partially enlarged cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] FIG. 7 is a partially enlarged cross-sectional view taken along line IX-IX in FIG. 6. [Figure 10] 1 is a partially enlarged plan view of a tire according to an embodiment of the present invention, centered on a tread edge. [Figure 11] FIG. 11 is a partially enlarged cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 7 is a partially enlarged cross-sectional view of a tire according to a modified example taken along line VII-VII in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0009] The embodiments of the present invention relate to the following aspects.

[0010] [Aspect 1] a circumferential main groove; an inner land portion defined by at least two of the circumferential main grooves; outer land portions disposed on the outer side in the tire width direction relative to the inner land portion, with the circumferential main groove interposed therebetween, The tire has an inclined groove, an inclined narrow groove, a reverse inclined groove, and a circumferential narrow groove, which are arranged in the outer land portion, the inclined groove extends from the circumferential main groove toward an outer side in the tire width direction, inclines from a leading side to a trailing side in the tire circumferential direction, and has a tip connected to a tread edge, the inclined narrow groove extends from the circumferential main groove toward the outer side in the tire width direction, inclines from the leading side to the trailing side in the tire circumferential direction, and has a tip located within the outer land portion, The reverse inclined groove extends from the trailing side to the leading side in the tire circumferential direction and is inclined from the inner side to the outer side in the tire width direction, The tire has circumferential narrow grooves arranged from the ground contact edge toward the inner side in the tire width direction, over a range of 5% to 15% of the tire width direction length from the tire equatorial plane to the ground contact edge.

[0011] [Aspect 2] Aspect 2. The tire according to aspect 1, wherein an angle formed between an extension direction of the reverse inclined groove and the tire circumferential direction is 5° or more and 50° or less.

[0012] [Aspect 3] The inclined groove is a main slope portion having a first groove depth; a bottom-up portion having a second groove depth shallower than the first groove depth between an end portion of the main inclined portion on an inner side in the tire width direction and the circumferential main groove; 3. The tire of claim 1 or 2, having

[0013] [Aspect 4] A tire according to any one of aspects 1 to 3, wherein the groove width of the circumferential narrow groove is 15% to 75% of the groove width of the circumferential main groove.

[0014] [Aspect 5] The tire according to any one of aspects 1 to 4, wherein two circumferential narrow grooves are provided on each side in the tire width direction, and when the groove width of the circumferential narrow groove on the outer side in the tire width direction of the two circumferential narrow grooves is Wout and the groove width of the circumferential narrow groove on the inner side in the tire width direction is Win, the tire satisfies the following formula (1): 0.3≦Wout / Win≦0.7...Equation (1)

[0015] [Aspect 6] The tire according to any one of aspects 1 to 5, wherein two circumferential narrow grooves are provided on each side in the tire width direction, and when the groove depth of the circumferential narrow groove on the outer side in the tire width direction of the two circumferential narrow grooves is Dout and the groove depth of the circumferential narrow groove on the inner side in the tire width direction of the two circumferential narrow grooves is Din, the following formula (2) is satisfied: 0.4≦Dout / Din≦0.8...Equation (2)

[0016] [Aspect 7] the inner land portion has a plurality of inner oblique sipes arranged in the tire circumferential direction, The tire according to any one of aspects 1 to 6, wherein the inner oblique sipe extends from the circumferential main groove toward the inside in the tire width direction, is inclined from the trailing edge to the leading edge in the tire circumferential direction, and has a chamfered portion with a depth of 2.0 mm or more.

[0017] [Aspect 8] the inner land portion is disposed at a position including the tire equatorial plane, The inner oblique sipes include a plurality of first inner oblique sipes and a plurality of second inner oblique sipes having groove lengths different from each other, the first inner oblique sipe has a tip that intersects with the tire equatorial plane and is located within the inner land portion, and a chamfered portion that intersects with the tire equatorial plane, The second inner oblique sipe does not intersect with the tire equatorial plane and has a tip located within the inner land portion. 8. The tire of embodiment 7.

[0018] [Aspect 9] the chamfered portion has a first chamfered portion and a second chamfered portion, The first chamfered portion is provided on the kick-out side of the inner oblique sipe, The second chamfered portion is provided on the leading side of the inner oblique sipe, Aspect 9. The tire of aspect 7 or 8, wherein the internal oblique sipe has a non-chamfered portion adjacent to the chamfered portion that is free of the chamfered portion.

[0019] [Aspect 10] A tire according to any one of aspects 7 to 9, wherein, when the depth of the inside oblique sipe is Dcs and the depth of the chamfered portion is Dc, the following formula (3) is satisfied: 0.4≦Dc / Dcs≦0.8...Equation (3)

[0020] [Aspect 11] A tire according to any one of aspects 1 to 10, wherein the tire satisfies the following formula (4), where LDE is the distance between tread ends in the tire width direction, and Wce is the length of the inner land portion in the tire width direction. 0.08≦Wce / LDE≦0.20...Equation (4)

[0021] [Aspect 12] A tire according to any one of aspects 1 to 11, wherein, when the groove width of the opening end of the inclined groove connected to the circumferential main groove is Wa and the groove width of the opening end of the inclined groove at the tread edge is Wb, the following formula (5) is satisfied: 0.3≦Wa / Wb≦0.8...Equation (5)

[0022] [Aspect 13] A tire according to any one of aspects 1 to 12, wherein the groove depth of the inclined narrow groove is 20% to 60% of the groove depth of the circumferential main groove.

[0023] [Aspect 14] The inclined narrow groove has a groove bottom sipe, The groove bottom sipe is formed at the groove bottom of the inclined narrow groove, A tire according to any one of aspects 1 to 13, wherein, when the groove depth of the inclined narrow groove is Dg and the groove depth of the groove bottom sipe is Ds, the following formula (6) is satisfied: 0.7≦Ds / Dg≦1.3...Equation (6)

[0024] [Aspect 15] A tire according to any one of aspects 1 to 14, wherein the groove depth of the reverse oblique groove is 40% or more and 80% or less of the groove depth of the circumferential main groove.

[0025] [Aspect 16] the outer land portion has a plurality of blocks defined by the inclined groove, the inclined narrow groove, and the reverse inclined groove, Aspects 16. The tire according to any one of aspects 1 to 15, wherein some of the plurality of blocks have external sipes.

[0026] [Aspect 17] 17. The tire of aspect 16, wherein the external sipes extend along the oblique grooves.

[0027] [Aspect 18] The inner land portion has an inner sipe, A tire according to any one of aspects 1 to 17, wherein the inner sipes extend along the tire width direction.

[0028] [Aspect 19] Among the plurality of blocks, an outermost block arranged outermost in the tire width direction has a protruding portion, Aspect 16 or 17. The tire according to aspect 16, wherein the protrusion protrudes outward in the tire width direction along the tire profile.

[0029] (definition) The tire radial direction refers to the direction perpendicular to the tire rotation axis, the tire radial inner side refers to the side toward the tire rotation axis in the tire radial direction, and the tire radial outer side refers to the side away from the tire rotation axis in the tire radial direction. The tire circumferential direction refers to the direction around the tire rotation axis as the center axis. The tire width direction refers to the direction parallel to the tire rotation axis, the inner side in the tire width direction refers to the side toward the tire equatorial plane (tire equatorial plane) in the tire width direction, and the outer side in the tire width direction refers to the side away from the tire equatorial plane in the tire width direction. The tire equatorial plane refers to a plane that is perpendicular to the tire rotation axis and passes through the center of the tire width. "Along" a given reference includes being along a direction within a range of less than ±20°, less than ±10°, or less than ±5° relative to the reference. "Center" includes the midpoint equidistant from two given points, and a range of ±10% of the distance from the midpoint between the two points. The circumferential main groove is a circumferential groove having a wear indicator that indicates the end of wear, and generally has a groove width of 5.0 mm or more and a groove depth of 5.0 mm or more. Note that the groove width and groove depth of the circumferential main groove are not limited to the above ranges. A sipe is a cut formed in a land portion, and generally has a groove width of less than 1.5 mm. The groove width is measured as the maximum distance between the opposing groove walls at the groove opening on the tread surface when the tire is mounted on a specified rim, inflated to a specified internal pressure, and under no load. In the case of a configuration in which the groove opening has a notch or chamfer, the groove width is the value measured with the intersection of an extension of the tread surface and an extension of the groove wall as the endpoint in a cross-sectional view parallel to the groove width direction and the groove depth direction. Groove depth is measured as the maximum distance from the tread surface to the bottom of the groove when the tire is mounted on a specified rim, inflated to the specified internal pressure, and under no load. If the groove in question has partial unevenness or sipes at the bottom of the groove, the groove depth shall be the value measured excluding the partial unevenness or sipes. The tread edges are the two ends of the tread pattern of the tire, and are also called design ends. The contact edge is the maximum position in the tire width direction on the contact surface between the tire and a flat plate when the tire is mounted on a specified rim, pressurized to a specified internal pressure, placed perpendicular to a flat plate in a stationary state, and subjected to a load corresponding to a specified load (80% of the maximum load capacity). The tire width along the tread surface between the two contact edges is called the contact width. The tire width along the tread surface from the tire equatorial plane to one of the contact edges is sometimes called half the contact width.

[0030] In the following explanation, a regular rim refers to an "applicable rim" as defined by JATMA, a "design rim" as defined by TRA, or a "measuring rim" as defined by ETRTO.

[0031] Similarly, in the following explanation, "normal internal pressure" refers to the "maximum air pressure" specified by JATMA, the maximum value specified in "Tire Load Limits at Various Cold Inflation Pressures" specified by TRA, or the "Inflation Pressures" specified by ETRTO. Also, "normal load" refers to the "maximum load capacity" specified by JATMA, the maximum value specified in "Tire Load Limits at Various Cold Inflation Pressures" specified by TRA, or the "Load Capacity" specified by ETRTO.

[0032] (Tire composition) A first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a diagram showing both sides in the tire width direction with respect to the tire equatorial plane CP of a tire 10 according to the first embodiment in a plan view seen from the outer side in the tire radial direction. Note that the drawing shows the tire portion in a state where the tire is mounted on a rim and has a normal internal pressure applied, and is in an unloaded state.

[0033] Although not shown in its entirety, the tire 10 of this embodiment has a meridian cross-sectional shape similar to that of a conventional pneumatic tire. That is, the tire 10 of this embodiment has, from the inner side to the outer side in the tire radial direction, a bead portion, a sidewall portion, a shoulder portion, and a tread portion 12. The tire 10 has, for example, a carcass layer extending from the tread portion 12 to both bead portions and wound around a pair of bead cores in the tire meridian cross-sectional view, and a belt layer and, in some cases, a belt cover layer on the outer side in the tire radial direction of the carcass layer.

[0034] The rotation direction of the tire 10 is specified. The tire 10 is equipped with a rotation direction indicator (not shown) that indicates the tire rotation direction. The tire rotation direction refers to the rotation direction that is frequently used when the tire is in use, for example, the rotation direction when the vehicle is moving forward. Based on the display of this rotation direction indicator, the first side of the block to contact the ground (the so-called leading side or toe side) and the last side to contact the ground (the so-called trailing side or heel side) are defined (see Figure 1). The leading side is the side that contacts the ground first when the tire rolls in the specified rotation direction, and the trailing side is the side opposite to the leading side. The rotation direction indicator is configured, for example, by marks or irregularities provided on the sidewall of the tire 10. The lower side in Figure 1 is the leading side. The upper side in Figure 1 is the trailing side.

[0035] The tread portion 12 is formed of a rubber material (tread rubber). The tread portion 12 has a tread surface 14 that comes into contact with the road surface when the vehicle is traveling. The tread surface 14 is annular, centered on the rotational axis of the tire 10, has a predetermined length in the tire width direction, and is continuous in the tire circumferential direction. A predetermined tread pattern is engraved on the tread surface 14. The tread pattern is asymmetric with respect to the tire equatorial plane CP, between both sides of the tire equatorial plane CP in the tire width direction. In FIG. 1, the symbol EL indicates the contact edge line (a line connecting consecutive contact edges E in the tire circumferential direction). The distance between the tread edges T along the tire profile is designated as LDE.

[0036] As shown in FIG. 1 , a tire 10 according to the first embodiment includes two circumferential main grooves 16, an inner land portion 18, and an outer land portion 20 on a tread surface 14. The tire 10 includes a first circumferential main groove 22 on one side of the tire equatorial plane CP in the tire width direction and a second circumferential main groove 24 on the other side in the tire width direction. The first circumferential main groove 22 and the second circumferential main groove 24 extend in the tire circumferential direction. That is, the first circumferential main groove 22 and the second circumferential main groove 24 are preferably formed so that imaginary lines parallel to the tire circumferential direction can pass through the grooves. Therefore, at least a portion of water that has flowed into the first circumferential main groove 22 and the second circumferential main groove 24 can move linearly in the tire circumferential direction through the first circumferential main groove 22 and the second circumferential main groove 24. In the following description, unless otherwise specified, the first circumferential main groove 22 and the second circumferential main groove 24 will be referred to as the circumferential main groove 16.

[0037] The inner land portion 18 is defined by two circumferential main grooves 16. The inner land portion 18 has an outer edge in the tire width direction defined by the two circumferential main grooves 16 and a shape that is continuous in the tire circumferential direction. The inner land portion 18 according to this embodiment is disposed at a position where the center in the tire width direction overlaps with the tire equatorial plane CP. The length in the tire width direction of the inner land portion 18 along the tire profile is denoted as Wce.

[0038] The inner land portion 18 has an inner oblique sipe 28 and an inner sipe 30. The inner oblique sipe 28 extends inward in the tire width direction from the circumferential main groove 16 and is inclined from the trailing edge to the leading edge. The inner oblique sipe 28 is linear. A plurality of the inner oblique sipes 28 are arranged in the tire circumferential direction at predetermined intervals. One end 32 of the inner oblique sipe 28 is connected to the circumferential main groove 16, and the other end 34 is located within the inner land portion 18. The groove length of the inner oblique sipe 28 is the distance between the one end 32 and the other end 34 of the inner oblique sipe 28.

[0039] As shown in FIG. 2 , the inner oblique sipes 28 include a first inner oblique sipe 36 and a second inner oblique sipe 38. The first inner oblique sipe 36 extends inward in the tire width direction from the circumferential main groove 16, is inclined from the trailing edge to the leading edge, and intersects with the tire equatorial plane CP. The other end 34f of the first inner oblique sipe 36 is disposed between the circumferential main groove 16 opposite the connected circumferential main groove 16 and the tire equatorial plane CP. The second inner oblique sipe 38 extends inward in the tire width direction from the circumferential main groove 16, is inclined from the trailing edge to the leading edge, and does not intersect with the tire equatorial plane CP. The other end 34s of the second inner oblique sipe 38 is disposed between the connected circumferential main groove 16 and the tire equatorial plane CP.

[0040] In this embodiment, the first inner oblique sipes 36 and the second inner oblique sipes 38 are arranged alternately in the tire circumferential direction. The first inner oblique sipes 36 and the second inner oblique sipes 38 are arranged on both sides of the tire equatorial plane CP. The first inner oblique sipes 36 and the second inner oblique sipes 38 are arranged in positions facing each other with respect to the tire equatorial plane CP. That is, in the tire 10 shown in FIG. 1 , the first inner oblique sipes 36 and the second inner oblique sipes 38 are arranged in this order from the trailing edge to the leading edge on the first circumferential main groove 22 side, and the second inner oblique sipes 38 and the first inner oblique sipes 36 are arranged in this order from the trailing edge to the leading edge on the second circumferential main groove 24 side.

[0041] The inner oblique sipe 28 has a chamfered portion 40. The chamfered portion 40 has a depth of 2.0 mm or more and 5.0 mm or less, and preferably 3.0 mm or more and 5.0 mm or less. The chamfered portion 40 has a first chamfered portion 42 and a second chamfered portion 44. The first chamfered portion 42 is formed on the edge of the inner oblique sipe 28 on the trailing side. The second chamfered portion 44 is formed on the edge of the inner oblique sipe 28 on the leading side.

[0042] The first inner oblique sipe 36 has a first chamfered portion 42 and a second chamfered portion 44. The first chamfered portion 42 is formed in a range from the other end 34f, which is located within the inner land portion 18 of the first inner oblique sipe 36, to the center of the groove length. One end 43 of the first chamfered portion 42 is located at the center of the groove length of the first inner oblique sipe 36, and the other end is integral with the other end 34f of the first inner oblique sipe 36 and is located within the inner land portion 18.

[0043] The second chamfered portion 44 provided on the first inner oblique sipe 36 is formed in a range from the center of the groove length of the first inner oblique sipe 36 to one end 32f of the first inner oblique sipe 36 connected to the circumferential main groove 16. One end 45 of the second chamfered portion 44 is disposed within the inner land portion 18, and the other end is integral with one end 32f of the first inner oblique sipe 36 and connected to the circumferential main groove 16.

[0044] 3, the first chamfered portion 42 and the second chamfered portion 44 may overlap in the groove width direction at the center of the groove length of the first inner oblique sipe 36. In this case, a chamfered portion 40 is provided on each side in the groove width direction with the first inner oblique sipe 36 as the center.

[0045] As shown in Figure 4, a second chamfered portion 44 is formed on the leading-out side of one end 32f of the first inner oblique sipe 36, centered on the first inner oblique sipe 36. No chamfered portion 40 is formed on the trailing-out side of one end 32f of the first inner oblique sipe 36, centered on the first inner oblique sipe 36. In other words, a non-chamfered portion 46 is provided on the trailing-out side of one end 32f of the first inner oblique sipe 36. The non-chamfered portion 46 has a substantially right-angled edge.

[0046] 5, a first chamfered portion 42 is provided on the trailing side of the other end 34f of the first inner oblique sipe 36, centered on the first inner oblique sipe 36. No chamfered portion 40 is formed on the leading side of the other end 34f of the first inner oblique sipe 36, centered on the first inner oblique sipe 36. In other words, a non-chamfered portion 46 is provided on the leading side of the other end 34f of the first inner oblique sipe 36.

[0047] The second inner oblique sipe 38 has a second chamfered portion 44 (FIG. 2). The second chamfered portion 44 is formed in a range from the other end 34s of the second inner oblique sipe 38, which is located within the inner land portion 18, to one end 32s of the second inner oblique sipe 38 connected to the circumferential main groove 16. In the second inner oblique sipe 38, no chamfered portion 40 is formed on the trailing-off side of the second inner oblique sipe 38 (similar to FIG. 4). That is, in the second inner oblique sipe 38, a non-chamfered portion 46 is provided on the trailing-off side.

[0048] The groove depth Dcs of the inner oblique sipe 28 is defined as Dcs ( FIG. 3 ). The groove depth Dcs of the inner oblique sipe 28 may be constant from one end 32 connected to the circumferential main groove 16 to the other end 34 located within the inner land portion 18. The groove depth Dcs of the inner oblique sipe 28 is measured as the maximum distance from the tread surface 14 to the bottom 28B of the inner oblique sipe 28 when the tire 10 is mounted on a specified rim, inflated to a specified internal pressure, and in an unloaded state. The depth of the chamfer 40 is defined as Dc. The depth Dc of the chamfer 40 is the distance between the intersection of an extended line of the tread surface 14 and an extended line of the groove wall 48 of the inner oblique sipe 28 and the intersection of the surface 41 of the chamfer 40 and the groove wall 48 when the tire 10 is mounted on a specified rim, inflated to a specified internal pressure, and in an unloaded state.

[0049] 2, the chamfer width gradually decreases from one end 43 toward the other end 34f of the first inner oblique sipe 36. The chamfer width is the distance, in a plan view, between the groove wall 48 of the inner oblique sipe 28 and the intersection of the surface 41 of the chamfered portion 40 and the tread surface 14. Although not shown, the first chamfered portion 42 has a depth Dc that gradually decreases from one end 43 toward the other end 34f of the first inner oblique sipe 36.

[0050] Each of the inner sipes 30 has a tip 31 on the outer side in the tire width direction connected to each of the circumferential main grooves 16. The inner sipes 30 may have a zigzag shape that inclines alternately to each side in the tire circumferential direction. The angle between the extension direction of the inner sipes 30 and the tire width direction is ±20° or less, 15° or less, or 10° or less. The extension direction of the inner sipes 30 is the direction of an imaginary line connecting each of the tips 31 connected to the circumferential main grooves 16.

[0051] The outer land portion (FIG. 1) 20 is adjacent to the inner land portion 18 on the outer side in the tire width direction, with two circumferential main grooves 16 sandwiched between them. The outer land portion 20 has a plurality of inclined grooves 50, inclined narrow grooves 52, and reverse inclined grooves 54. The outer land portion 20 has a plurality of blocks 56 defined by the plurality of inclined grooves 50, inclined narrow grooves 52, and reverse inclined grooves 54.

[0052] The inclined grooves 50 extend from the circumferential main groove 16 outward in the tire width direction and are inclined from the leading side to the trailing side. A plurality of inclined grooves 50 are arranged at predetermined intervals in the tire circumferential direction. A tip 58 of the inclined groove 50 on the inner side in the tire width direction is connected to the circumferential main groove 16, and a tip 60 on the outer side in the tire width direction is connected to the tread edge T. The inclined grooves 50 may extend in the direction along the tire width direction in a range from the ground contact edge E to the outer side in the tire width direction.

[0053] As shown in FIG. 4, the opening width of a tip 58 of the inclined groove 50 connected to the circumferential main groove 16 is defined as Wa. The opening width Wa is the distance between the end points where the groove wall 16w of the circumferential main groove 16 intersects with the groove wall 50w of the inclined groove 50. The opening width of a tip 60 of the inclined groove 50 connected to the tread edge T is defined as Wb. The opening width Wb is the distance between the end points where the tread edge T intersects with the groove wall 50w of the inclined groove 50. When the tips 58, 60 of the inclined groove 50 have chamfered portions, the opening widths Wa, Wb are the distances between the end points where an extension line of the groove wall 50w of the inclined groove 50 intersects with an extension line of the groove wall 16w of the circumferential main groove 16 or the tread edge T. The groove width of the inclined groove 50 shown in FIG. 4 gradually increases from the inner side in the tire width direction to the outer side in the tire width direction. The groove width W1 of the inclined groove 50 is preferably 70% to 120% and more preferably 80% to 110% of the groove width Wm of the circumferential main groove 16. The groove width W1 of the inclined groove 50 is the average value of the opening width Wa and the opening width Wb.

[0054] As shown in FIG. 5 , the inclined groove 50 has a main inclined portion 62 and a bottom-up portion 64. The main inclined portion 62 has a second groove depth D2. The second groove depth D2 is 50% or more and 120% or less of the groove depth Dm of the circumferential main groove 16. The bottom-up portion 64 is disposed between an inner tip 66 of the main inclined portion 62 in the tire width direction and a groove wall 16w of the circumferential main groove 16. The bottom-up portion 64 has a third groove depth D3. The third groove depth D3 is shallower than the second groove depth D2. The third groove depth D3 is 15% or more and 70% or less of the second groove depth D2. The length of the bottom-up portion 64 in the tire width direction is preferably 3 mm or more and 15 mm or less, and more preferably 5 mm or more and 10 mm or less.

[0055] The raised bottom portion 64 shown in Figure 5 extends from a tip 66 on the inner side in the tire width direction of the main inclined portion 62 toward the circumferential main groove 16. The raised bottom portion 64 is connected to the circumferential main groove 16. The raised bottom portion 64 has an inclined surface 68 and a flat surface 70. The inclined surface 68 extends from the tip 66 on the inner side in the tire width direction of the main inclined portion 62 toward the circumferential main groove 16 and is inclined outward in the tire radial direction. The flat surface 70 extends from a tip 72 on the inner side in the tire width direction of the inclined surface 68 toward the circumferential main groove 16 in a direction along the tread surface 14.

[0056] The inclined narrow grooves 52 extend from the circumferential main groove 16 toward the outside in the tire width direction and are inclined from the leading-in side to the trailing-out side in the tire circumferential direction. A plurality of inclined narrow grooves 52 are arranged at predetermined intervals in the tire circumferential direction. A tip 74 of the inclined narrow groove 52 on the inside in the tire width direction is connected to the circumferential main groove 16, and a tip 76 on the outside in the tire width direction is arranged in the outer land portion 20. The inclined narrow grooves 52 are preferably arranged on an extension line of the inner inclined groove 28. The inclined narrow grooves 52 and the inclined grooves 50 according to this embodiment are arranged alternately in the tire circumferential direction.

[0057] The groove width W2 of the inclined narrow groove 52 is preferably 20% or more and 80% or less of the groove width W1 of the inclined groove 50, and more preferably 35% or more and 55% or less.

[0058] The groove width W2 of the inclined narrow groove 52 is preferably 5% to 25% of the block width W4, and more preferably 10% to 20%. The block width W4 refers to the widthwise length of the block 56c adjacent to the circumferential main groove 16. The widthwise length of the block 56c is measured as follows. First, the intersection of an extension of the groove wall 50w of the inclined groove 50 on the trailing edge of the target block 56c and an extension of the groove wall 16w of the circumferential main groove 16 is defined as a first endpoint P1. Next, the intersection of a straight line drawn from the first endpoint P1 and perpendicular to the trailing edge groove wall 50w of the block 56c with the leading edge groove wall 50w of the block 56c is defined as a second endpoint P2. The distance between the first endpoint P1 and the second endpoint P2 is defined as the block width W4.

[0059] The inclined narrow groove 52 has a groove bottom sipe 78 (FIG. 4). The groove bottom sipe 78 is formed at the groove bottom 52u of the inclined narrow groove 52. That is, the groove bottom sipe 78 is a groove that has an opening 78t at the groove bottom 52u of the inclined narrow groove 52 and a bottom surface 78b on the inner side in the tire radial direction, and extends in a direction along the inclined narrow groove 52.

[0060] The groove bottom sipes 78 are preferably shorter than the groove length of the inclined narrow grooves 52 and do not communicate with the reverse inclined grooves 54. That is, the length of the groove bottom sipes 78 is defined as Ls, and the groove length of the inclined narrow grooves 52 is defined as Lg. The length Ls of the groove bottom sipes 78 is the length in a direction perpendicular to the groove width direction and groove depth direction of the groove bottom sipes 78. The groove length Lg of the inclined narrow grooves 52 is defined as the distance between the midpoints of the groove widths at the tips 74, 76 of the inclined narrow grooves 52 that connect to the reverse inclined grooves 54, when targeting the inclined narrow grooves 52 provided in a certain block 56 defined by reverse inclined grooves 54 on both sides in the tire width direction. In this case, the groove length Ls of the groove bottom sipes 78 is preferably 0.75 or more ≦(Ls / Lg)≦0.95.

[0061] As shown in Fig. 6, the groove depth of the inclined narrow groove 52 is Dg, and the groove depth of the groove bottom sipe 78 is Ds. The groove depth Dg of the inclined narrow groove 52 is preferably 20% to 60% of the groove depth Dm of the circumferential main groove 16, and more preferably 30% to 50%. The inclined narrow groove 52 is arranged along the inclined groove 50. The groove bottom sipe 78 is arranged at the center of the inclined narrow groove 52 in the groove width direction.

[0062] The reverse inclined grooves 54 extend from the trailing edge to the leading edge in the tire circumferential direction and are inclined from the inner side to the outer side in the tire width direction ( FIG. 4 ). There are preferably two to four reverse inclined grooves 54 on each side of the tire equatorial plane CP. Although not shown, the inner and outer ends of the reverse inclined grooves 54 in the tire width direction are disposed within the outer land portion 20. The reverse inclined grooves 54 intersect with the inclined grooves 50 and the inclined narrow grooves 52. The groove width W3 of the reverse inclined groove 54 is preferably 30% to 90% of the groove width Wm of the circumferential main groove 16, and more preferably 40% to 60%.

[0063] The angle θc between the extension direction of the reverse inclined grooves 54 and the tire circumferential direction is preferably 5° or more and 50° or less, and more preferably 10° or more and 30° or less (FIG. 1). The angle θc between the extension direction of the reverse inclined grooves 54 and the tire circumferential direction may be specified for each block. That is, the angle θc between the extension direction of the reverse inclined grooves 54 and the tire circumferential direction is the angle between the tire circumferential direction and a first imaginary line L1 connecting the midpoint of the groove width at the trailing-side end and the midpoint of the groove width at the leading-side end of the reverse inclined groove 54 in each block 56.

[0064] As shown in FIG. 7, the fourth groove depth D4 of the reverse oblique groove 54 is preferably 40% to 80% of the groove depth Dm of the circumferential main groove 16, and more preferably 50% to 70%.

[0065] The outer land portion 20 further has a circumferential narrow groove 88 (FIG. 1). The circumferential narrow groove 88 is continuous in the tire circumferential direction and intersects with the oblique grooves 50 and the oblique narrow grooves 52. The groove width Wsub of the circumferential narrow groove 88 is preferably 15% to 75% of the groove width Wm of the circumferential main groove, and more preferably 20% to 50%. By having the groove width Wsub of the circumferential narrow groove 88 be 15% to 75% of the groove width Wm of the circumferential main groove, it is possible to improve snow performance and wet performance while suppressing a deterioration in dry performance. The groove depth Dsub of the circumferential narrow groove 88 is preferably 10% to 60% of the groove depth Dm of the circumferential main groove, and more preferably 15% to 50%.

[0066] The circumferential narrow grooves 88 are arranged in an outer region SH in the tire width direction of the outer land portion 20. The outer region SH is a region that is continuous in the tire circumferential direction, and refers to a range of 0.05 × Wh (mm) or more and 0.15 Wh (mm) or less from the tire tread edge E to the inner side in the tire width direction, where Wh is the distance in the tire width direction along the tire profile from the tire equatorial plane CP to the tire tread edge E.

[0067] In Figure 1, a line extending from the ground edge E to the inside in the tire width direction and parallel to the ground edge line EL at a position 5% of half the ground contact width Wh is defined as a second imaginary line L2. A line extending from the ground edge E to the inside in the tire width direction and parallel to the ground edge line EL at a position 15% of half the ground contact width Wh is defined as a third imaginary line L3. The outer region SH is the range between the second imaginary line L2 and the third imaginary line L3.

[0068] Preferably, two circumferential narrow grooves 88 are formed in the outer regions SH on each side of the tire equatorial plane CP. That is, the tire 10 preferably has an outer narrow groove 90 and an inner narrow groove 92 in the outer regions SH on each side of the tire equatorial plane CP in the tire width direction. The outer narrow groove 90 is disposed on the outer side in the tire width direction. The inner narrow groove 92 is disposed on the inner side of the outer narrow groove 90 in the tire width direction.

[0069] 10 and 11, the groove width of the outer narrow groove 90 is Wout, and the groove depth of the outer narrow groove 90 is Dout. The groove width of the inner narrow groove 92 is Win, and the groove depth of the inner narrow groove 92 is Din.

[0070] Each of the multiple blocks 56 has an outer sipe 84 (FIG. 2). Preferably, one or two outer sipes 84 are provided in each block 56. Preferably, one or two outer sipes 84 are provided in each block 56, on both sides of the inclined narrow groove 52 in the tire circumferential direction. The outer sipes 84 may be zigzag-shaped, inclining alternately to each side in the tire circumferential direction. The angle θd between the extension direction of the outer sipes 84 and the extension direction of the inclined narrow groove 52 is ±20° or less, ±15° or less, or ±10° or less. The extension direction of the outer sipes 84 is the direction of an imaginary line connecting the inner end and the outer end in the tire width direction. The extension direction of the inclined narrow groove 52 is the direction of an imaginary line connecting the midpoint of the groove width at the inner end in the tire width direction within the block 56 in which the outer sipe 84 is formed and the midpoint of the groove width at the outer end in the tire width direction.

[0071] The outer land portion 20 has an outermost block 56s arranged outermost in the tire width direction. The outermost block 56s has an outer edge in the tire circumferential direction defined by the inclined grooves 50, an outer edge on the inner side in the tire width direction defined by the reverse inclined grooves 54, and an inclined narrow groove 52 in the tire circumferential center.

[0072] The outermost tip 76 of the inclined narrow groove 52 in the tire width direction is disposed in the outermost block 56s. The outermost block 56s has a protruding portion 86. The protruding portion 86 protrudes outward in the tire width direction from the outer tip 76 of the inclined narrow groove 52 in the tire width direction along the tire profile. The protruding portion 86 is disposed in a region outer than the ground contact edge E in the tire width direction.

[0073] In this embodiment, the protrusion 86 has an edge 86e extending in a direction intersecting the tire circumferential direction. Multiple edges 86e are arranged in the tire circumferential direction. In the case of FIG. 10, the edge 86e extends from the inner side to the outer side in the tire width direction, and is inclined from the leading side to the trailing side. The height of the protrusion 86 is preferably 0.5 mm or more and 3.0 mm or less. The height of the protrusion 86 is the distance from the tire surface in the absence of the protrusion 86 to the surface of the top of the protrusion 86.

[0074] The groove width Wout of the outer narrow groove 90 is preferably smaller than the groove width Win of the inner narrow groove 92. Specifically, the groove width Wout of the outer narrow groove 90 and the groove width Win of the inner narrow groove 92 preferably satisfy the following formula (1).

[0075] 0.3≦Wout / Win≦0.7...Equation (1)

[0076] The groove depth Dout of the outer narrow groove 90 is preferably shallower than the groove depth Din of the inner narrow groove 92. Specifically, the groove depth Dout of the outer narrow groove 90 and the groove depth Din of the inner narrow groove 92 preferably satisfy the following formula (2):

[0077] 0.4≦Dout / Din≦0.8...Equation (2)

[0078] It is preferable that the depth Dcs of the inside oblique sipe and the depth Dc of the chamfered portion satisfy the following formula (3).

[0079] 0.4≦Dc / Dcs≦0.8...Equation (3)

[0080] When the distance LDE between the tread ends T in the tire width direction and the length Wce of the inner land portion 18 in the tire width direction are taken as LDE and Wce, respectively, it is preferable that the following formula (4) be satisfied.

[0081] 0.08≦Wce / LDE≦0.20...Equation (4) It is preferable that the groove width Wa of the tip 58 of the inclined groove 50 connecting to the circumferential main groove 16 and the groove width Wb of the tip 60 of the inclined groove 50 at the tread edge T satisfy the following formula (5).

[0082] 0.3≦Wa / Wb≦0.8...Equation (5)

[0083] It is preferable that the groove depth Dg of the inclined narrow groove 52 and the groove depth Ds of the groove bottom sipe 78 satisfy the following formula (6).

[0084] 0.7≦Ds / Dg≦1.3...Equation (6)

[0085] The tire 10 of this embodiment described above is obtained through each of the usual manufacturing steps, i.e., a tire material mixing step, a tire material processing step, a green tire molding step, a vulcanization step, and a post-vulcanization inspection step, etc. When manufacturing the tire of this embodiment, convex portions and concave portions corresponding to a predetermined tread pattern are formed on the inner wall of a vulcanization mold, and vulcanization is carried out using this mold.

[0086] (Action and effect) The tire 10 according to this embodiment includes a circumferential main groove 16, an inner land portion 18 defined by the two circumferential main grooves 16, and outer land portions 20 disposed on the outer side of the inner land portion 18 in the tire width direction, with the circumferential main groove 16 sandwiched between them. The outer land portion 20 also includes an inclined groove 50, an inclined narrow groove 52, and a reverse inclined groove 54. The inclined groove 50 is inclined from the leading edge to the trailing edge in the tire circumferential direction, and its tip 60 connects to the tread edge T. The inclined narrow groove 52 extends from the circumferential main groove 16 toward the outer side in the tire width direction, and is inclined from the leading edge to the trailing edge in the tire circumferential direction. The reverse inclined groove 54 extends from the trailing edge to the leading edge in the tire circumferential direction, and is inclined from the inner side to the outer side in the tire width direction.

[0087] On snowy roads, the tire 10 compacts snow that has entered the grooves. When driving force, braking force, or lateral force during cornering acts on the tire in this state, so-called snow column shear force is generated in the snow in the grooves. The tire 10 has circumferential main grooves 16, inclined grooves 50, inclined narrow grooves 52, and reverse inclined grooves 54, which enable it to exert excellent snow column shear force and provide excellent drainage. This gives the tire 10 excellent snow and wet performance.

[0088] The outer tip 76 of the inclined narrow groove 52 in the tire width direction is disposed within the outermost block 56s. This prevents a decrease in the rigidity of the outermost block 56s. The groove width W2 of the inclined narrow groove 52 is 20% to 80% of the groove width W1 of the inclined groove 50, which prevents a decrease in the rigidity of the outer land portion 20. This provides the tire 10 with excellent dry performance.

[0089] As a result, the tire 10 has excellent snow performance, wet performance, and dry performance.

[0090] By providing two or more reverse inclined grooves 54 on each side in the tire width direction relative to the tire equatorial plane CP, the tire 10 has excellent snow performance and wet performance. By providing four or less reverse inclined grooves 54, a decrease in rigidity of each block 56 is suppressed. Therefore, the tire 10 has excellent dry performance.

[0091] By making the groove width W2 of the inclined narrow groove 52 5% or more of the block width W4, snow column shear force can be more reliably exerted. By making the groove width W2 of the inclined narrow groove 52 25% or less of the block width W4, a sufficient ground contact area can be secured. Therefore, the tire 10 can suppress a decrease in dry performance.

[0092] By making the angle θc between the extension direction of the reverse inclined grooves 54 and the tire circumferential direction 50° or more, the tire 10 can more reliably exert snow shear force during driving or braking. By making the angle θc 50° or less, the tire 10 can more reliably exert snow column shear force during cornering.

[0093] The inclined groove 50 has the bottom-raised portion 64, which can suppress a decrease in rigidity on the inner side in the tire width direction of the outer land portion 20. The tire 10 has excellent dry performance because a decrease in rigidity on the inner side in the tire width direction where the ground contact pressure is higher is suppressed.

[0094] By arranging the circumferential narrow grooves 88 in the outer region SH, it is possible to improve snow performance while maintaining dry performance. By arranging the circumferential narrow grooves 88 inward in the tire width direction from the second imaginary line L2, drainage is improved and snow column shear force is obtained during cornering, resulting in excellent wet and snow performance. By arranging the circumferential narrow grooves 88 outward in the tire width direction from the third imaginary line L3, a decrease in rigidity of the outer land portion 20 is suppressed, thereby suppressing a decrease in dry performance.

[0095] The groove width Wout of the outer narrow groove 90 is smaller than the groove width Win of the inner narrow groove 92, which prevents a decrease in block rigidity near the tread edge E and prevents a decrease in dry performance. The groove depth Dout of the outer narrow groove 90 is smaller than the groove depth Din of the inner narrow groove, which prevents a decrease in block rigidity near the tread edge E and provides excellent dry performance.

[0096] The inner oblique sipes 28 have chamfered portions 40 with a depth Dc of 2.0 mm or more. As a result, when the tire 10 comes into contact with the road surface, the groove walls 48 of the inner oblique sipes 28 closest to the tread surface 14 come into contact with each other. When the groove walls 48 of the inner oblique sipes 28 come into contact with each other, the edges of the chamfered portions 40 and the edges of the non-chamfered portions 46 provided on the inner oblique sipes 28 come into contact with the road surface. As a result, the tire 10 has excellent snow performance during braking and driving.

[0097] The inner oblique sipes 28 have a plurality of first inner oblique sipes 36 and a plurality of second inner oblique sipes 38 that are different in groove length. By having the first inner oblique sipes 36 that intersect with the tire equatorial plane CP, the tire 10 can more reliably obtain excellent snow performance. By having the second inner oblique sipes 38 that do not intersect with the tire equatorial plane CP, it is possible to suppress a decrease in rigidity of the tread portion 12 near the tire equatorial plane CP where ground pressure is high, and therefore the tire 10 has excellent dry performance.

[0098] The inner oblique sipe 28 has a chamfered portion 40 and a non-chamfered portion 46 where the chamfered portion 40 is not formed, thereby improving wet performance and snow performance while suppressing a decrease in rigidity of the tread portion 12.

[0099] The depth Dcs of the inboard oblique sipe and the depth Dc of the chamfered portion satisfy the above formula (3). In the tire 10, by being equal to or greater than the lower limit of the above formula (3), the size of the chamfered portion 40 can be made to be equal to or greater than a predetermined size. Therefore, the tire 10 can obtain excellent wet performance and snow performance. By being equal to or less than the upper limit of the above formula (3), the size of the chamfered portion 40 can be made to be equal to or smaller than a predetermined size. Therefore, the tire 10 can suppress a decrease in rigidity of the tread portion 12.

[0100] The distance LDE between the tread ends T in the tire width direction and the length Wce of the inner land portion 18 in the tire width direction satisfy the above formula (2). The tire 10 can obtain excellent dry performance when the relationship between the distance LDE and the length Wce is equal to or greater than the lower limit of the above formula (2). The tire can obtain excellent snow performance when the relationship between the distance LDE and the length Wce is equal to or less than the upper limit of the above formula (2).

[0101] The groove width Wa of the tip 58 of the inclined groove 50 connecting to the circumferential main groove 16 and the groove width Wb of the tip 60 of the inclined groove 50 at the tread end T satisfy the above formula (3). When the relationship between the groove width Wa and the groove width Wb is within the range of the above formula (3), the tire 10 can obtain the desired rigidity on the inner side in the tire width direction, and can obtain excellent snow column shear force by ensuring the groove area on the outer side in the tire width direction.

[0102] The tire 10 can more reliably exert snow column shear force by making the groove depth Dg of the inclined narrow groove 52 20% or more of the groove depth Dm of the circumferential main groove 16. The tire 10 can suppress a decrease in block rigidity by making the groove depth Dg of the inclined narrow groove 52 60% or less of the groove depth Dm of the circumferential main groove 16.

[0103] By having the groove bottom sipes 78, the inclined narrow grooves 52 have a larger cross-sectional area than inclined narrow grooves having the same groove width and groove depth but without the groove bottom sipes 78, so the tire 10 can improve its snow performance and wet performance while suppressing a decrease in block rigidity.

[0104] The groove depth Dg of the inclined narrow groove 52 and the groove depth Ds of the groove bottom sipe 78 satisfy the above formula (4). In the tire 10, the relationship between the groove depth Dg and the groove depth Ds is equal to or greater than the lower limit of the above formula (4), so that the proportion of the groove bottom sipe 78 is equal to or greater than a certain value, i.e., the cross-sectional area of ​​the inclined narrow groove 52 is equal to or less than a predetermined size, thereby suppressing a decrease in block rigidity and providing excellent dry performance. In the tire 10, the relationship between the groove depth Dg and the groove depth Ds is equal to or less than the upper limit of the above formula (4), so that the proportion of the groove bottom sipe 78 is equal to or less than a certain value, i.e., the cross-sectional area of ​​the inclined narrow groove 52 is equal to or greater than a predetermined size, thereby providing excellent wet and snow performance.

[0105] The groove depth D4 of the reverse oblique grooves 54 is 40% or more of the groove depth Dm of the circumferential main grooves 16, thereby more reliably exerting snow column shear force. The groove depth D4 of the reverse oblique grooves 54 is 80% or less of the groove depth Dm of the circumferential main grooves 16, thereby suppressing a decrease in block rigidity of the tire 10 and providing excellent dry performance.

[0106] Some of the multiple blocks 56 in the outer land portion 20 have outer sipes 84, which deform when the tire is stepped on so that the groove walls come into contact with each other, and one edge of the outer sipes 84 comes into contact with the road surface. This allows the tire 10 to achieve excellent snow performance. By providing each block 56 with two or fewer outer sipes 84, it is possible to prevent a decrease in the rigidity of the block 56. Because the outer sipes 84 extend along the inclined narrow grooves 52, the blocks 56 in which the outer sipes 84 are formed are more likely to deform in the direction that widens the groove width of the inclined narrow grooves 52 when the tire is stepped on, thereby more reliably exerting snow column shear force.

[0107] The inner sipes 30 extend along the tire width direction, and therefore, the inner land portion 18 deforms during driving and braking, forming edges on the inner sipes 30. Therefore, the tire 10 has excellent driving and braking performance on snow.

[0108] The protrusions 86 protrude outward in the tire width direction along the tire profile, thereby providing the effect of shoveling snow when driving on snow. The protrusions 86 have edges 86e that extend in a direction intersecting the tire circumferential direction. Because multiple edges 86e are arranged in the tire circumferential direction, the tire 10 can more reliably shovel snow.

[0109] (Variation) The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present invention.

[0110] For example, in the above embodiment, the tire 10 has been described as having the raised bottom portion 64 in the inclined groove 50, but the present invention is not limited to this and may not have the raised bottom portion 64. The tire 10 has been described as having the raised bottom portion 64 connected to the circumferential main groove 16, but the present invention is not limited to this. As shown in FIG. 12 , a deep groove portion 94 may be provided between the raised bottom portion 64 and the circumferential main groove 16. The groove depth of the deep groove portion 94 may be the same as the second groove depth D2 of the main inclined portion 62. Furthermore, the raised bottom portion 64 is not limited to having an inclined surface 68 and a flat surface 70, and may not have the flat surface 70. Furthermore, the raised bottom portion 64 may not have an inclined surface 68.

[0111] It is preferable that the groove bottom sipes 78 do not communicate with the circumferential main grooves 16. As shown in Fig. 16, it is preferable that the groove depth Dg of the inclined narrow grooves 52 is shallower than the groove depth Dm of the circumferential main grooves 16. In this case, the inner tip 78ce of the groove bottom sipes 78 in the tire width direction is disposed within the inclined narrow groove 52. That is, the groove bottom 52u of the inclined narrow groove 52 is disposed between the inner tip 78ce of the groove bottom sipes 78 in the tire width direction and the groove wall 16w of the circumferential main groove 16. This enables the tire 10 to suppress a decrease in tread rigidity in the vicinity of the tire equatorial plane CP.

[0112] In the above embodiment, the tread pattern is asymmetric with respect to the tire equatorial plane CP, but the present invention is not limited to this, and the tread pattern may be symmetric with respect to the tire equatorial plane CP.

[0113] The inner land portion 18 is not limited to being disposed at a position where its center in the tire width direction overlaps with the tire equatorial plane CP, but may be disposed at a position where its center in the tire width direction is away from the tire equatorial plane CP to one side or the other side in the tire width direction. The inner land portion 18 may be disposed at a position where it does not overlap with the tire equatorial plane CP.

[0114] The number of circumferential main grooves 16 is not limited to two, but may be three or more. When three or more circumferential main grooves 16 are included, the land portion closest to the tire equatorial plane CP or including the tire equatorial plane CP is defined as the inner land portion 18.

[0115] The inclined groove 50 is not limited to a groove width that gradually increases from Wa to Wb from the inner side in the tire width direction to the outer side in the tire width direction. For example, the inclined groove 50 may have a portion where the groove width gradually increases and a portion where the groove width gradually decreases from the inner side in the tire width direction to the outer side in the tire width direction. The inclined groove 50 may include, at any position between the tip on the inner side in the tire width direction and the tip on the outer side in the tire width direction, a portion whose groove width is smaller than the groove width of the inclined groove 50 located on the inner side in the tire width direction.

[0116] The inner land portion 18 is not limited to a case in which it has a circumferential narrow groove 26 extending in the tire circumferential direction, and may not have the circumferential narrow groove 26 .

[0117] Although the above description has been given of a case in which two circumferential narrow grooves 88 are formed in each of the outer regions SH on each side in the tire width direction, the present invention is not limited to this. One circumferential narrow groove 88 may be formed in each of the outer regions SH on each side in the tire width direction, or three or more circumferential narrow grooves 88 may be formed. When there are three or more circumferential narrow grooves 88, the groove arranged on the outermost side in the tire width direction in the outer region SH is referred to as the outer narrow groove 90, and the groove arranged on the innermost side in the tire width direction in the outer region SH is referred to as the inner narrow groove 92.

[0118] The inner land portion 18 is not limited to having the inner inclined groove 28 and the inner sipe 30, and may include either one of them, or may not include both.

[0119] The inner sipes 30 are not limited to being zigzag slanted alternately to each side in the tire circumferential direction, but may also be linear. The outer sipes 84 are not limited to being zigzag slanted alternately to each side in the tire circumferential direction, but may also be linear.

[0120] The inclined grooves 50 and the inclined narrow grooves 52 are not limited to being arranged alternately in the tire circumferential direction, and for example, a plurality of inclined grooves 50 may be arranged continuously in the tire circumferential direction. Alternatively, a plurality of inclined narrow grooves 52 may be arranged continuously in the tire circumferential direction.

[0121] The inclined narrow groove 52 is not limited to having the groove bottom sipe 78. The inclined narrow groove 52 does not have to have the groove bottom sipe 78.

[0122] The angle formed between the extending direction of the reverse inclined grooves 54 and the tire circumferential direction may be less than 5° or may be greater than 50°.

[0123] The inclined groove 50 or the inclined narrow groove 52 is not limited to being arranged on the extension line of the inner inclined groove 28, but may also be arranged between the extension lines of multiple inner inclined grooves 28 arranged in the tire circumferential direction.

[0124] The outer sipes 84 are not limited to extending along the inclined narrow grooves 52, but may extend in a direction that exceeds ±20° with respect to the extension direction of the inclined narrow grooves 52. The inner sipes 30 are not limited to extending along the tire width direction, but may extend in a direction that exceeds ±20° with respect to the tire width direction.

[0125] The groove width Wsub of the circumferential narrow groove 88 may be less than 15% of the groove width Wm of the circumferential main groove 16, or may be more than 75%.

[0126] The depth Dc of the chamfered portion 40 may be less than 2.0 mm. For example, the depth Dc of the chamfered portion 40 may be 0.6 mm or more.

[0127] The inner oblique sipes 28 may not have the first inner oblique sipes 36, and may not have the second inner oblique sipes 38. The second inner oblique sipes 38 may intersect with the tire equatorial plane CP.

[0128] The first inner oblique sipes 36 may be arranged continuously in the tire circumferential direction or may be arranged opposite each other with respect to the tire equatorial plane CP. The second inner oblique sipes 38 may be arranged continuously in the tire circumferential direction or may be arranged opposite each other with respect to the tire equatorial plane CP.

[0129] The first chamfered portion 42 is not limited to a case where the chamfer width gradually decreases from one end 43 to the other end 34f of the first inner oblique sipe 36, but may have a constant chamfer width or may gradually increase from one end 43 to the other end 34f. The depth Dc of the first chamfered portion 42 is not limited to a case where the chamfer width gradually decreases from one end 43 to the other end 34f of the first inner oblique sipe 36, but may be constant or may gradually increase.

[0130] Although the groove depth Dcs of the inner oblique sipe 28 has been described as being constant from one end 32 connected to the circumferential main groove 16 to the other end 34 located within the inner land portion 18, the present invention is not limited thereto. For example, the inner oblique sipe may have a portion where the groove depth is constant from the one end 32 toward the inside in the tire width direction, and a portion where the groove depth gradually decreases from the constant groove depth portion toward the other end. Also, the first inner oblique sipe 36 may have a portion where the groove depth is constant from one end 45 of the second chamfered portion 44 to the other end 32f connected to the circumferential main groove 16 and gradually decreases from the one end 45 of the second chamfered portion 44 toward the inside in the tire width direction to the other end 34f of the first chamfered portion 42.

[0131] (Example) Tires according to Examples 1 to 35 and pneumatic tires according to Reference Examples 1 to 3 were manufactured, each having a tire size of 245 / 45R19 102V (specified by JATMA) and having a raised portion with the shape shown in Fig. 1 when mounted on a rim. Detailed conditions of these tires are as shown in Tables 1 and 2 below.

[0132] In Tables 1 and 2, each item conforms to the definition described in this specification. For example, the column "Location of circumferential narrow groove (%)" indicates the percentage (%) of the distance between the circumferential narrow groove and the tread edge relative to the 1 / 2 contact width Wh. The column "First chamfered portion or second chamfered portion" indicates "present" if either the first chamfered portion or the second chamfered portion is present. The column "Extension direction of inclined narrow groove relative to outer sipe" indicates "parallel" if the outer sipe extends along the inclined narrow groove.

[0133] The tires of Examples 1 to 35 and Reference Examples 1 to 3 thus prepared were mounted on 19x9.0J aluminum rims at an air pressure (F / R) of 250 kPa / 250 kPa, and each test tire was mounted on a 4WD test vehicle (displacement: 3000 cc). Evaluations were then carried out on the handling stability on wet roads, snowy roads, and dry roads according to the following procedures.

[0134] (Steering stability on wet roads) A test driver conducted a sensory evaluation while driving on a wet road surface (1mm deep water). The evaluation results were expressed as an index, with the conventional example being set at 100. The higher the index value, the better the handling stability on wet road surfaces.

[0135] (Steering stability on snowy roads) A test driver conducted a sensory evaluation while driving on packed snow roads. The evaluation results were expressed as an index, with the conventional example being set at 100. The higher the index value, the better the handling stability on snowy roads.

[0136] (Steering stability on dry roads) A test driver conducted a sensory evaluation while driving on dry roads where high speeds are possible. The evaluation results were expressed as an index, with the conventional example being set at 100. The higher the index value, the better the handling stability on dry roads.

[0137] [Table 1]

[0138] [Table 2]

[0139] From Tables 1 and 2 above, it can be seen that the tires of the examples are superior to the tires of the reference examples in steering stability on wet roads, on snowy roads, and on dry roads. [Explanation of symbols]

[0140] 10 Tires 12 Tread section 14 Tread surface 16 Circumferential main groove 16w Groove wall (circumferential main groove) 18 Inner land area 20 Outer land area 22 1st circumferential main groove 24 2nd circumferential main groove 28 Inner Inclined Sipe 28b bottom (inner inclined sipe) 30 inner sipe 31 Tip (internal sipe) 32 One end (inner inclined sipe) 34 Other end (inner inclined sipe) 34f Other end of first inner inclined sipe 34s Other end of second inner inclined sipe groove 36 First inner inclined sipe 38 Second inner inclined sipe 40 Chamfered part 41 Surface (chamfered part) 42 First chamfer 43 One end (first chamfered part) 44 Second chamfer 45 One end (second chamfered part) 46 Non-chamfered part 48 Groove wall (inner inclined sipe) 50 Slant groove 50w groove wall (slanted groove) 52 Slanted narrow groove 52w Groove wall (slanted narrow groove) 52u groove bottom (slanted narrow groove) 54 Reverse slope groove 56 blocks 56c Block (adjacent to the circumferential main groove) 56s outermost block 58 Tip of inner side in tire width direction (inclined groove) 60 Outer edge of tire width direction (inclined groove) 62 Main slope 64 Bottom raised part 66 Tire width direction inner tip (main inclined part) 68 Slope 70 flat surface 72 Tire width direction inner tip (inclined surface) 74 Tip of inner side in tire width direction (inclined narrow groove) 76 Outer edge of tire width direction (inclined narrow groove) 78 Groove bottom sipe 78t Opening (groove bottom sipe) 78b Bottom (groove bottom sipe) 80 Tip of inner side in tire width direction (reverse inclined groove) 82 Outer edge of tire width direction (reverse inclined groove) 84 outer sipes 86 Protrusion 86e Edge (protruding part) 88 Circumferential narrow groove 90 Outer narrow groove 92 Medial narrow groove 94 Deep groove part CP tire equatorial plane E Ground end EL ground terminal wire LDE: The distance between the tread edges across the tire. Wce: Length of inner land portion in the tire width direction Wm Circumferential main groove width W1 Groove width (slope groove) W2 Groove width (slanted narrow groove) W3 Groove width (reverse slope groove) W4 block width Dm Circumferential main groove depth D1 First groove depth (inner inclined groove) D2 Second groove depth (main inclined part) D3 3rd groove depth (raised bottom) D4 groove depth (reverse slope groove) D5 Depth (recess) Dg Groove depth (inclined narrow groove) Ds Groove depth (groove bottom sipe) Dc Depth (chamfered part) T Tread Edge P1 1st end point P2 2nd end point Lg Groove length (inclined narrow groove) Ls Groove length (groove bottom sipe) L1 First virtual line (extension direction of reverse inclined groove) L2 2nd virtual line (outer area) L3 Third virtual line (outer area) SH outer area θa angle (angle between the extension direction of the first inclined portion and the tire circumferential direction) θb angle (angle between the extension direction of the second inclined portion and the tire circumferential direction) θc angle (angle between the extension direction of the reverse inclined groove and the tire circumferential direction) θd angle (outside sipe)

Claims

1. a circumferential main groove; an inner land portion defined by at least two of the circumferential main grooves; outer land portions disposed on the outer side in the tire width direction relative to the inner land portion, with the circumferential main groove interposed therebetween, The tire has an inclined groove, an inclined narrow groove, a reverse inclined groove, and a circumferential narrow groove, which are arranged in the outer land portion, the inclined groove extends from the circumferential main groove toward an outer side in the tire width direction, inclines from a leading side to a trailing side in the tire circumferential direction, and has a tip connected to a tread edge, the inclined narrow groove extends from the circumferential main groove toward the outer side in the tire width direction, inclines from the leading side to the trailing side in the tire circumferential direction, and has a tip located within the outer land portion, The reverse inclined groove extends from the trailing side to the leading side in the tire circumferential direction and is inclined from the inner side to the outer side in the tire width direction, The tire, wherein the circumferential narrow grooves are arranged from the ground contact edge toward the inner side in the tire width direction over a range of 5% to 15% of the tire width direction length from the tire equatorial plane to the ground contact edge.

2. The tire according to claim 1 , wherein an angle formed between an extension direction of the reverse inclined groove and a tire circumferential direction is equal to or greater than 5° and equal to or less than 50°.

3. The inclined groove is a main slope portion having a first groove depth; a bottom-up portion having a second groove depth shallower than the first groove depth between an end portion of the main inclined portion on an inner side in the tire width direction and the circumferential main groove; 10. The tire of claim 1, wherein:

4. The tire according to claim 1, wherein the groove width of the circumferential narrow groove is 15% or more and 75% or less of the groove width of the circumferential main groove.

5. 2. The tire according to claim 1, wherein two circumferential narrow grooves are provided on each side in the tire width direction, and when the groove width of the circumferential narrow groove on the outer side in the tire width direction of the two circumferential narrow grooves is Wout and the groove width of the circumferential narrow groove on the inner side in the tire width direction of the two circumferential narrow grooves is Win, the following formula (1) is satisfied: 0.3≦Wout / Win≦0.7...Formula (1)

6. 2. The tire according to claim 1, wherein two circumferential narrow grooves are provided on each side in the tire width direction, and when the groove depth of the circumferential narrow groove on the outer side in the tire width direction of the two circumferential narrow grooves is Dout and the groove depth of the circumferential narrow groove on the inner side in the tire width direction is Din, the following formula (2) is satisfied: 0.4≦Dout / Din≦0.8...Formula (2)

7. the inner land portion has a plurality of inner oblique sipes arranged in the tire circumferential direction, 2. The tire according to claim 1, wherein the inner oblique sipe extends from the circumferential main groove toward the inside in the tire width direction, is inclined from the trailing edge side to the leading edge side in the tire circumferential direction, and has a chamfered portion with a depth of 2.0 mm or more.

8. the inner land portion is disposed at a position including the tire equatorial plane, The inner oblique sipes include a plurality of first inner oblique sipes and a plurality of second inner oblique sipes having groove lengths different from each other, the first inner oblique sipe has a tip that intersects with the tire equatorial plane and is located within the inner land portion, and a chamfered portion that intersects with the tire equatorial plane, the second inner oblique sipe does not intersect with the tire equatorial plane and has a tip located within the inner land portion, 8. The tire of claim 7.

9. the chamfered portion has a first chamfered portion and a second chamfered portion, The first chamfered portion is provided on the kick-out side of the inner oblique sipe, The second chamfered portion is provided on the leading side of the inner oblique sipe, The tire of claim 7 , wherein the internal oblique sipe has a non-chamfered portion adjacent to the chamfered portion that does not have the chamfered portion.

10. The tire according to claim 7, wherein, when a depth of the inner oblique sipe is Dcs and a depth of the chamfered portion is Dc, the following formula (3) is satisfied: 0.4≦Dc / Dcs≦0.8...Formula (3)

11. The tire according to claim 1, wherein the following formula (4) is satisfied, where LDE is a distance between tread ends in the tire width direction, and Wce is a length of the inner land portion in the tire width direction. 0.08≦Wce / LDE≦0.20...Formula (4)

12. 2. The tire according to claim 1, wherein, when a groove width of an opening end of the inclined groove connected to the circumferential main groove is Wa and a groove width of an opening end of the inclined groove at a tread end is Wb, the following formula (5) is satisfied: 0.3≦Wa / Wb≦0.8...Formula (5)

13. The tire according to claim 1, wherein the groove depth of the inclined narrow groove is 20% or more and 60% or less of the groove depth of the circumferential main groove.

14. The inclined narrow groove has a groove bottom sipe, The groove bottom sipe is formed at the groove bottom of the inclined narrow groove, The tire according to claim 1, wherein the following formula (6) is satisfied, where Dg is a groove depth of the inclined narrow groove and Ds is a groove depth of the groove bottom sipe. 0.7≦Ds / Dg≦1.3...Formula (6)

15. The tire according to claim 1, wherein the groove depth of the reverse oblique groove is 40% or more and 80% or less of the groove depth of the circumferential main groove.

16. the outer land portion has a plurality of blocks defined by the inclined groove, the inclined narrow groove, and the reverse inclined groove, The tire of claim 1 , wherein some of the blocks have external sipes.

17. 17. The tire of claim 16, wherein the external sipes extend along the oblique striations.

18. The inner land portion has an inner sipe, The tire according to claim 1 , wherein the inner sipe extends along the tire width direction.

19. Among the plurality of blocks, an outermost block arranged outermost in the tire width direction has a protruding portion, The tire according to claim 16, wherein the protrusion protrudes outward in the tire width direction along the tire profile.

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