tire

Abstract

To achieve a balance between wet performance, wear resistance, and stone drilling resistance. [Solution] The tread portion includes a plurality of circumferential main grooves 20 extending along the tire circumferential direction and arranged in the tire width direction, a plurality of lug grooves 50, 60 extending along the tire width direction and arranged in the tire circumferential direction and opening into the circumferential main grooves 20, a recess 20U in the groove wall 20c of the circumferential main groove 20 in which the groove width is widened in at least a portion between adjacent lug grooves 50, 60 in the tire circumferential direction, and a bottom upper portion 90 provided in the recess 20U and projecting from the groove bottom 20b side of the circumferential main groove 20 toward the tread surface 15A. A feature thereof is that the wall portion 90c rising from the groove bottom 20b of the circumferential main groove 20 is continuous on the same plane with the groove wall 20c of the circumferential main groove 20 in the portion of the circumferential main groove 20 that does not have a recess 20U, and is positioned on at least one of both groove walls 20c of the circumferential main groove 20 in the area excluding the lug grooves 50, 60.

Description

Technical Field

[0001] This invention relates to a tire.

Background Art

[0002] Conventionally, for example, Patent Document 1 discloses a technique for improving the performance on ice and snow while suppressing a decrease in uneven wear performance for a studless tire.

[0003] Also conventionally, for example, Patent Document 2 discloses a technique for improving the resistance to stone drilling, in which at least one of the circumferential grooves and the widthwise grooves has a groove wall with a bent portion, and the groove width on the groove bottom side from the bent portion is formed narrower than the groove width of the opening portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, in the case of studless tires in a category that is often used throughout the year, a block pattern with high wet performance is likely to be adopted in order to drive on an ice and snow road surface from a dry road surface. However, the block pattern has a large groove area, and there is a risk that the wear resistance performance and the resistance to stone drilling performance will decrease.

[0006] An object of this invention is to provide a tire capable of achieving both wet performance, wear resistance performance, and resistance to stone drilling performance.

Means for Solving the Problems

[0007] To achieve the above objective, a tire according to one aspect of the present invention includes, in the tread portion, a plurality of circumferential main grooves extending along the tire circumferential direction and arranged in the tire width direction; a plurality of lug grooves extending along the tire width direction and arranged in the tire circumferential direction and opening into the circumferential main grooves; a recess in the groove wall of the circumferential main groove in which the groove width is widened in at least a portion between adjacent lug grooves in the tire circumferential direction; and a bottom portion provided in the recess and projecting toward the tread surface from the groove bottom side of the circumferential main groove, wherein the wall portion rising from the groove bottom of the circumferential main groove is in the same plane as the groove wall in the portion of the circumferential main groove that does not have the recess, and is provided on at least one of the two groove walls of the circumferential main groove in the area excluding the lug grooves. [Effects of the Invention]

[0008] This invention makes it possible to achieve a balance between wet performance, wear resistance, and stone drilling resistance. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a meridional cross-sectional view of a pneumatic tire according to an embodiment. [Figure 2] Figure 2 is a plan view of the tread portion of a pneumatic tire according to an embodiment. [Figure 3] Figure 3 is a partially enlarged plan view of the tread portion of a pneumatic tire according to an embodiment. [Figure 4] Figure 4 is a partially enlarged perspective view of the tread portion of a pneumatic tire according to an embodiment. [Figure 5] Figure 5 is a partially enlarged cross-sectional view (cross-sectional view AA in Figure 3) of the tread portion of the pneumatic tire according to the embodiment. [Figure 6] Figure 6 is a partially enlarged plan view of another example of the tread portion of a pneumatic tire according to the embodiment. [Figure 7] Figure 7 is a chart showing the results of a performance test of a pneumatic tire according to the embodiment. [Figure 8] Figure 8 is a chart showing the results of a performance test of a pneumatic tire according to the embodiment. [Figure 9] Figure 9 is a chart showing the results of a performance test of a pneumatic tire according to the embodiment. [Figure 10] Figure 10 is a chart showing the results of a performance test of a pneumatic tire according to the embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited by these embodiments. Furthermore, the components of these embodiments include those that are substituted and obvious for substitution while maintaining the identity of the invention. In addition, the multiple modifications described in these embodiments can be arbitrarily combined within the scope of what is obvious to those skilled in the art.

[0011] In the following description, the tire radial direction refers to the direction perpendicular to the tire rotation axis (not shown), which is the rotation axis of the pneumatic tire 1 of the embodiment. The inner side of the tire radial direction refers to the side toward the tire rotation axis in the tire radial direction, and the outer side of the tire radial direction 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 central axis. The tire width direction refers to the direction parallel to the tire rotation axis. The inner side of the tire width direction refers to the side toward the tire equatorial plane (tire equator line) CL in the tire width direction, and the outer side of the tire width direction refers to the side away from the tire equatorial plane CL in the tire width direction. The tire equatorial plane CL is a plane perpendicular to the tire rotation axis and passing through the center of the tire width of the pneumatic tire 1. The position of the tire equatorial plane CL in the tire width direction coincides with the tire width direction center line, which is the center position of the pneumatic tire 1 in the tire width direction. The tire equator line refers to a line on the tire equatorial plane CL that runs along the tire circumferential direction of the pneumatic tire 1. Furthermore, a meridional cross-section of a tire (meridian section) refers to the cross-section obtained when the tire is cut along a plane containing the tire's axis of rotation.

[0012] FIG. 1 is a meridional sectional view of the pneumatic tire 1 according to the embodiment. In this embodiment, a radial tire for light trucks, which is classified as a tire for vehicles such as light commercial vehicles and light trucks, and is applied as a studless tire in a category that is often used throughout the year, will be described.

[0013] The pneumatic tire 1 according to the embodiment has an annular structure centered on the tire rotation axis, and includes a pair of bead cores 11, a pair of bead fillers 12, a carcass layer 13, a belt layer 14, tread rubber 15, a pair of sidewall rubbers 16, and a pair of rim cushion rubbers 17.

[0014] The pair of bead cores 11 are formed by winding one or more bead wires made of steel in an annular and multiple manner, and are respectively embedded in the bead portions on both sides in the tire width direction to form the cores of the bead portions.

[0015] [[ID=@1]] The pair of bead fillers 12 are respectively arranged on the outer periphery in the tire radial direction of the pair of bead cores 11 to reinforce the bead portions.

[0016] The carcass layer 13 has a single-layer structure composed of one carcass ply or a multi-layer structure formed by laminating a plurality of carcass plies. In the pneumatic tire 1 according to the embodiment, the carcass layer 13 is composed of two carcass plies 131 and 132. The carcass layer 13 is bridged in a toroidal shape between the two bead cores to form the skeleton of the tire. Further, both ends of the carcass layer 13 are wound back and locked to the outside in the tire width direction so as to wrap the bead core 11 and the bead filler 12. Further, the carcass layer 13 is formed by covering a plurality of carcass cords made of an organic fiber material or steel with coat rubber and performing rolling processing, and in the case of a radial tire, it has a cord angle (defined as the inclination angle of the longitudinal direction of the carcass cord with respect to the tire circumferential direction) of 80° or more and 90° or less in absolute value.

[0017] The belt layer 14 is formed by laminating a plurality of belt plies 141 to 144, and is wound around the outer periphery of the carcass layer 13. In the pneumatic tire 1 of the embodiment, the belt plies 141 to 144 are composed of crossed belts 141, 142, a belt cover 143, and a pair of belt edge covers 144, 144. The crossed belts 141, 142 are formed by coating a plurality of belt cords made of steel or organic fiber material with coating rubber and performing rolling processing. The crossed belts 141, 142 have a so-called cross-ply structure in which the belt cords have mutually different signed cord angles with respect to the tire circumferential direction and are laminated so as to cross each other. The crossed belts 141, 142 are laminated and arranged on the outer side in the tire radial direction of the carcass layer 13. The belt cover 143 and the pair of belt edge covers 144 are formed by coating a belt cover cord made of steel or organic fiber material with coating rubber. The belt cover 143 and the pair of belt edge covers 144 have a cord angle in which the belt cover cord extends along the tire circumferential direction. The belt cover 143 and the belt edge covers 144 are formed by winding a strip material formed by coating one or a plurality of belt cover cords with coating rubber around the outer peripheral surface of the crossed belts 141, 142 a plurality of times in a spiral manner in the tire circumferential direction. The belt cover 143 is arranged to cover the entire area of the crossed belts 141, 142. The pair of belt edge covers 144 are arranged to cover the edge portions on both sides in the tire width direction of the crossed belts 141, 142 from the outer side in the tire radial direction.

[0018] The tread rubber 15 is arranged on the outer periphery in the tire radial direction of the carcass layer 13 and the belt layer 14, and constitutes the tread portion of the pneumatic tire 1. The tread rubber 15 forms a tread surface 15A (also referred to as a running surface) on the outer peripheral surface that contacts the road surface during running in the tread portion. The end portion on the outer side in the tire width direction of the tread surface 15A becomes the grounding end T (see FIG. 2).

[0019] The pair of sidewall rubbers 16 are respectively arranged on the outer sides in the tire width direction of the carcass layer 13, and constitute the sidewall portions on both sides in the tire width direction of the pneumatic tire 1.

[0020] A pair of rim cushion rubbers 17 extend from the inside in the tire radial direction to the outside in the tire width direction of the folded-over portion of each bead core 11 and carcass layer 13, forming the rim fitting surface of the bead portion.

[0021] As shown in Figure 2, the pneumatic tire 1 of the embodiment has a tread pattern on the tread surface 15A of the tread portion. Here, each dimension of the tread pattern is measured in an unloaded state with the pneumatic tire 1 mounted on a specified rim and filled with a specified internal pressure. The above-mentioned contact end T is defined as the position of the maximum width in the tire width direction at the contact surface between the tread surface 15A and the flat plate when the tire is mounted on a specified rim, filled with a specified internal pressure, the tire equatorial plane CL is placed perpendicular to the flat plate, and a load corresponding to a specified load is applied.

[0022] A specified rim refers to a "standard rim" as defined by JATMA, a "design rim" as defined by TRA, or a "measuring rim" as defined by ETRTO. Furthermore, specified internal pressure refers to the "maximum air pressure" as defined by JATMA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" as defined by TRA, or "INFLATION PRESSURES" as defined by ETRTO. Finally, specified load refers to the "maximum load capacity" as defined by JATMA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" as defined by TRA, or "LOAD CAPACITY" as defined by ETRTO.

[0023] The groove width is measured as the maximum distance between opposing groove walls at the groove opening (opening end) on the surface of the tread surface 15A when the tire is mounted on a specified rim and filled to the specified internal pressure in an unloaded state. In configurations where the groove opening has a notch or chamfer, the groove width is measured using the intersection point of the extension line (profile) of the tread surface 15A and the extension line of the groove wall as the endpoint in a cross section parallel to the tire width direction and tire diameter direction.

[0024] The groove depth is measured as the maximum distance from the surface of the tread surface 15A to the bottom of the groove when the tire is mounted on a specified rim and filled to the specified internal pressure in an unloaded state. In addition, if the groove depth has a configuration with partial irregularities or sipes at the bottom of the groove, these are excluded from the measurement.

[0025] As shown in Figures 1 to 3, the pneumatic tire 1 of the embodiment has a circumferential main groove 20, a circumferential fine groove 40, lug grooves 50, 60, sipes 70, 80, and a bottom upper part 90 on the tread surface 15A of the tread portion.

[0026] The circumferential main grooves 20 are provided extending along the circumferential direction of the tire. Three circumferential main grooves 20 are provided side by side in the tire width direction. The circumferential main grooves 20 include one center circumferential main groove 21 on the tire equatorial plane CL and two shoulder circumferential main grooves 22 provided on the tire width side of each center circumferential main groove 21. Each circumferential main groove 20 may be defined as a groove that has a wear indicator display obligation as specified by JATMA.

[0027] As shown in Figure 3, the circumferential main groove 20 is formed linearly along the circumferential direction of the tire and has recesses 20U formed by indentations in opposing groove walls 20c that form a groove width W1, and protrusions 20P formed by the recesses 20U. These recesses 20U and protrusions 20P are arranged alternately in the circumferential direction of the tire and alternately reversed in the width direction of the tire.

[0028] The circumferential main groove 20 has a groove width W1 of 4.0 mm to 9.0 mm (dimension between the opening edge 20a to the tread surface 15A: see Figure 5). The circumferential main groove 20 also has a groove depth H1 of 9.0 mm to 16.0 mm (dimension from the tread surface 15A to the groove bottom 20b: see Figure 5). Furthermore, the maximum dimension A1 in the tire width direction between the two recesses 20U of the circumferential main groove 20 (see Figure 2) is 4.0 mm to 12.0 mm.

[0029] Each circumferential main groove 20 defines a land area 30 in the tire width direction. The land area 30 includes two rows of center land areas 31 defined between the center circumferential main groove 21 and each shoulder circumferential main groove 22, and two rows of shoulder land areas 32 defined between each shoulder circumferential main groove 22 and each contact end T.

[0030] As shown in Figure 2, the circumferential grooves 40 extend along the circumferential direction of the tire and divide the land area 30 in the tire width direction. The circumferential grooves 40 are grooves with a narrower groove width than the circumferential main grooves 20. The circumferential grooves 40 have a groove width of 1.0 [mm] to 3.0 [mm]. In addition, the circumferential grooves 40 have a groove depth of 3.0 [mm] to 13.0 [mm].

[0031] The circumferential groove 40 includes a center circumferential groove 41 that demarcates each center land portion 31, and a shoulder circumferential groove 42 that demarcates each shoulder land portion 32.

[0032] The center circumferential groove 41 extends in the circumferential direction of the tire and bends in the tire width direction, giving it a zigzag shape. Specifically, as shown in Figure 2, the center circumferential groove 41 has a zigzag shape because the bent portion 41F reverses its bending direction in the circumferential direction of the tire, and the area between them is a straight portion 41S that is inclined with respect to the circumferential direction of the tire. Furthermore, the straight portion 41S between the bent portions 41F of the center circumferential groove 41 is divided by a dividing portion 41T. Therefore, the center circumferential groove 41 has a narrower groove width than the circumferential main groove 20, extends along the circumferential direction of the tire, bends in the tire width direction, giving it a zigzag shape, and is provided divided at multiple locations in the circumferential direction of the tire. Note that the center circumferential groove 41 may not have a zigzag shape and may be provided in a straight line along the circumferential direction of the tire. Also, the center circumferential groove 41 may be provided continuously in the circumferential direction of the tire. Furthermore, the narrow groove 41 in the center circumferential direction has an inclination angle of 5° or more and 45° or less in absolute terms with respect to the tire circumferential direction of the straight section 41S.

[0033] The shoulder circumferential groove 42 extends in the circumferential direction of the tire and bends in the tire width direction, giving it a zigzag shape. Specifically, as shown in Figure 2, the shoulder circumferential groove 42 has a zigzag shape because the bent portion 42F reverses its bending direction in the circumferential direction of the tire, and the section between them is a straight portion 42S inclined with respect to the circumferential direction of the tire. Therefore, the shoulder circumferential groove 42 has a narrower groove width than the circumferential main groove 20, extends along the circumferential direction of the tire, and bends in the tire width direction, giving it a zigzag shape. Note that the shoulder circumferential groove 42 may not have a zigzag shape and may be provided in a straight line along the circumferential direction of the tire. Also, the shoulder circumferential groove 42 may be divided at multiple locations in the circumferential direction of the tire, similar to the center circumferential groove 41. Note that the inclination angle of the straight portion 42S of the shoulder circumferential groove 42 with respect to the circumferential direction of the tire is 5° or more and 45° or less in absolute value.

[0034] The lug groove 50, also called the center lug groove, extends in a straight or curved shape along the tire width direction in each center land area 31, and is provided in multiples in the tire circumferential direction, dividing each center land area 31 into multiple sections in the tire circumferential direction.

[0035] The center lug groove 50 includes a center inner lug groove 51 and a center outer lug groove 52.

[0036] The center inner lug groove 51 is located in the center lug groove 50 provided in each center land portion 31, on the inner side in the tire width direction, separated by the center circumferential narrow groove 41. The center inner lug groove 51 has a groove width of 2.5 mm to 6.5 mm. The center inner lug groove 51 also has a groove depth of 4.0 mm to 13.0 mm. The center inner lug groove 51 is provided with one end opening into the center circumferential narrow groove 41 and the other end opening into the center circumferential main groove 21. The center inner lug groove 51 opens at the position of the bend 41F of the center circumferential narrow groove 41, and has one bend 41F of the center circumferential narrow groove 41 between adjacent center inner lug grooves in the tire circumferential direction. Therefore, one end of the center inner lug groove 51 opens at the position of the bend 41F of the center circumferential narrow groove 41 that bends in the same direction. The center circumferential narrow groove 41 has two straight sections 41S extending in different inclination directions with respect to a single bend 41F between adjacent center inner lug grooves 51 in the tire circumferential direction, and each of these straight sections 41S has at least one dividing section 41T. The other end of the center inner lug groove 51 is open to the center circumferential main groove 21. The center circumferential main groove 21 reverses the pair of convex portions 20P and concave portions 20U of the opposing groove walls between adjacent center inner lug grooves 51 in the tire circumferential direction. The center inner lug grooves 51 provided in each center land portion 31 with the center circumferential main groove 21 in between are arranged so that their other ends face each other in the tire width direction. Furthermore, the inner lug grooves 51 provided in each center land portion 31, which are situated between the main circumferential grooves 21, have an inclination angle with respect to the tire width direction that is between 0° and 45° in absolute value, and are arranged in the same inclination direction as shown in Figure 2.

[0037] The center outer lug groove 52 is located outside the tire width direction, separated by the center circumferential narrow groove 41, in the center lug groove 50 provided in each center land portion 31. The center outer lug groove 52 has a groove width of 2.5 [mm] to 6.5 [mm]. The center outer lug groove 52 also has a groove depth of 4.0 [mm] to 13.0 [mm]. The center outer lug groove 52 is provided with one end opening into the center circumferential narrow groove 41 and the other end opening into the shoulder circumferential main groove 22. The center outer lug groove 52 opens at the position of the bend 41F of the center circumferential narrow groove 41, and has one bend 41F of the center circumferential narrow groove 41 between adjacent center outer lug grooves in the tire circumferential direction. Therefore, one end of the center outer lug groove 52 opens at the position of the bend 41F of the center circumferential narrow groove 41 that bends in the same direction. The center circumferential narrow groove 41 has two straight sections 41S extending in different inclination directions, separated by a single bend 41F where the center inner lug groove 51 opens, between adjacent center outer lug grooves 52 in the tire circumferential direction, and each of these straight sections 41S has at least one dividing section 41T. The center inner lug groove 51 and the center outer lug groove 52 are arranged in a staggered pattern, with one end of each opening alternately in the tire circumferential direction at the position of the bend 41F of the center circumferential narrow groove 41, and not overlapping with each other in the projection in the tire width direction. The other end of the center outer lug groove 52 opens into the shoulder circumferential main groove 22. The shoulder circumferential main groove 22 reverses the pair of convex portions 20P and concave portions 20U of the opposing groove walls between adjacent center outer lug grooves 52 in the tire circumferential direction. Furthermore, the outer center lug grooves 52 provided in each center land portion 31 with the main center circumferential groove 21 in between have an absolute inclination angle of 0° or more and 45° or less with respect to the tire width direction, are arranged in the same inclination direction as shown in Figure 2, and are arranged in the opposite inclination direction to the inner center lug groove 51.

[0038] The center inner lug groove 51, along with the center circumferential narrow groove 41 and the center circumferential main groove 21, divides the inner side of each center land portion 31 in the tire width direction into multiple center inner blocks 31A arranged in the tire circumferential direction. The center outer lug groove 52, along with the center circumferential narrow groove 41 and the shoulder circumferential main groove 22, divides the outer side of each center land portion 31 in the tire width direction into multiple center outer blocks 31B arranged in the tire circumferential direction. The center inner blocks 31A and center outer blocks 31B are arranged in a staggered pattern in the tire width direction. Furthermore, the center inner blocks 31A and center outer blocks 31B arranged in a staggered pattern are connected to each other at the dividing portion 41T of the center circumferential narrow groove 41.

[0039] The center inner block 31A has edges formed along each groove 21, 41, and 51 by a set of convex portion 20P and concave portion 20U on the groove wall of the center circumferential main groove 21, a single bent portion 41F and two straight portions 41S on the center circumferential narrow groove 41, and the straight or curved shape of the center inner lug groove 51. The center outer block 31B has edges formed along each groove 21, 41, and 52 by a set of convex portion 20P and concave portion 20U on the groove wall of the shoulder circumferential main groove 22, a single bent portion 41F and two straight portions 41S on the center circumferential narrow groove 41, and the straight or curved shape of the center outer lug groove 52.

[0040] The lug grooves 60, also called shoulder lug grooves, extend in a straight or curved shape along the tire width direction in each shoulder land area 32, and are arranged in multiples in the tire circumferential direction, dividing each shoulder land area 32 into multiple sections in the tire circumferential direction.

[0041] The shoulder lug groove 60 includes an inner shoulder lug groove 61 and an outer shoulder lug groove 62.

[0042] The inner shoulder lug groove 61 is located inward in the tire width direction, separated by the shoulder circumferential narrow groove 42, within the shoulder lug groove 60 provided on each shoulder land portion 32. The inner shoulder lug groove 61 has a groove width of 2.5 mm to 6.5 mm. The inner shoulder lug groove 61 also has a groove depth of 3.0 mm to 7.0 mm. The inner shoulder lug groove 61 is provided with one end opening into the shoulder circumferential narrow groove 42 and the other end opening into the shoulder circumferential main groove 22. The inner shoulder lug groove 61 opens at the position of the bend 42F of the shoulder circumferential narrow groove 42 at one end, and has one bend 42F of the shoulder circumferential narrow groove 42 between adjacent inner shoulder lug grooves in the tire circumferential direction. Therefore, the inner shoulder lug groove 61 opens at the position of the bend 42F of the shoulder circumferential narrow groove 42 that bends in the same direction. The shoulder circumferential narrow groove 42 has two straight sections 42S extending in different inclination directions, separated by a single bend 42F, between adjacent shoulder inner lug grooves 61 in the tire circumferential direction. Although not explicitly shown in the figure, if the shoulder circumferential narrow groove 42 has a division, there is at least one division in the two straight sections 42S extending in different inclination directions separated by the single bend 42F. The other end of the shoulder inner lug groove 61 opens into the shoulder circumferential main groove 22. The shoulder circumferential main groove 22 reverses the pair of convex portions 20P and concave portions 20U of the opposing groove walls between adjacent shoulder inner lug grooves 61 in the tire circumferential direction. Furthermore, the shoulder inner lug groove 61 and the center outer lug groove 52 provided in the center land portion 31, separated by the shoulder circumferential main groove 22, do not have their openings facing each other in the tire width direction, but are offset in the tire circumferential direction. Furthermore, each inner shoulder lug groove 61 provided on each shoulder land portion 32 has an inclination angle of 0° or more and 45° or less in absolute value with respect to the tire width direction, and is arranged in the same inclination direction as shown in Figure 2. Also, each inner shoulder lug groove 61 provided on each shoulder land portion 32 is arranged in the same inclination direction as the center outer lug groove 52 provided on the center land portion 31, separated by the shoulder circumferential main groove 22, as shown in Figure 2.

[0043] The outer shoulder lug groove 62 is located on the outer side in the tire width direction, separated by the shoulder circumferential narrow groove 42, within the shoulder lug groove 60 provided on each shoulder land portion 32. The outer shoulder lug groove 62 has a groove width of 3.5 mm to 9.5 mm. The outer shoulder lug groove 62 also has a groove depth of 7.0 mm to 14.0 mm. The outer shoulder lug groove 62 is provided with one end opening into the shoulder circumferential narrow groove 42 and the other end opening into the contact end T. The outer shoulder lug groove 62 has one end opening at the position of the bend 42F of the shoulder circumferential narrow groove 42, and there is one bend 42F of the shoulder circumferential narrow groove 42 between adjacent outer shoulder lug grooves in the tire circumferential direction. Therefore, one end of the outer shoulder lug groove 62 opens at the position of the bend 42F of the shoulder circumferential narrow groove 42 that bends in the same direction. Furthermore, the inner shoulder lug groove 61 and the outer shoulder lug groove 62 alternately open in the tire circumferential direction at the position of the bent portion 42F of the shoulder circumferential narrow groove 42 at one end, and are arranged in a staggered pattern that does not overlap with each other in projection in the tire width direction. In addition, at the other end of the outer shoulder lug groove 62 that opens at the contact end T, a chamfered portion 62a is formed in the groove depth direction from the tread surface 15A so that the groove width widens outward in the tire width direction. Each outer shoulder lug groove 62 provided on each shoulder land portion 32 has an inclination angle with respect to the tire width direction of 0[°] or more and 45[°] or less in absolute value, and is arranged in the same inclination direction as shown in Figure 2, and is arranged in a different inclination direction from the inner shoulder lug groove 61. In this embodiment, the outer shoulder lug groove 62 is provided approximately parallel to the tire width direction at an angle of 0[°] ± 3[°] with respect to the tire width direction.

[0044] The inner shoulder lug groove 61, along with the circumferential narrow shoulder groove 42 and the circumferential main shoulder groove 22, divides the inner side of each shoulder land portion 32 in the tire width direction into multiple inner shoulder blocks 32A arranged in the tire width direction. The outer shoulder lug groove 62, along with the circumferential narrow shoulder groove 42 and the contact end T, divides the outer side of each shoulder land portion 32 in the tire width direction into multiple outer shoulder blocks 32B arranged in the tire width direction. The inner shoulder blocks 32A and outer shoulder blocks 32B are arranged in a staggered pattern in the tire width direction.

[0045] The inner shoulder block 32A has edges formed along each groove 22, 42, and 61 by a set of convex portion 20P and concave portion 20U on the groove wall of the main shoulder circumferential groove 22, a single bent portion 42F and two straight portions 42S of the narrow shoulder circumferential groove 42, and the straight or curved shape of the inner shoulder lug groove 61. The outer shoulder block 32B has edges formed along each groove 42, 62 and the ground contact end T by a single bent portion 42F and two straight portions 42S of the narrow shoulder circumferential groove 42, the straight shape of the ground contact end T, and the straight or curved shape and chamfer portion 62a of the outer shoulder lug groove 62.

[0046] As shown in Figures 2 and 3, the sipes 70 are provided on each center inner block 31A and each center outer block 31B of each center land portion 31. The sipes 70 are formed in a zigzag shape on the tread surface 15A. The sipes 70 are formed in a straight line in the depth direction (tire diameter direction). The sipes 70 may be formed in a zigzag shape in the depth direction. The sipes 70 include open sipes 71 and closed sipes 72. The open sipes 71 are provided on each center inner block 31A, extending along the tire width direction, with one end opening into the center circumferential main groove 21 and the other end opening into the center circumferential narrow groove 41 and communicating with one end of the center inner lug groove 51. Furthermore, the open sipes 71 are provided in each center outer block 32B, extending along the tire width direction, with one end opening into the shoulder circumferential main groove 22 and the other end opening into the center circumferential narrow groove 41 and communicating with one end of the center outer lug groove 52. The open sipes 71 have a groove width of less than 1.0 [mm]. The open sipes 71 also have a depth of 4.5 [mm] or more and 12.0 [mm] or less. The closed sipes 72 are provided in each center inner block 31A and each center outer block 31B, with both ends terminating within the block. The closed sipes 72 have a groove width of less than 1.0 [mm]. The closed sipes 72 also have a depth of 4.5 [mm] or more and 12.0 [mm] or less. The open sipes 71 and closed sipes 72 are arranged in each center inner block 31A, extending substantially parallel to the inclination angle of the center inner lug groove 51 within a range of ±3 [°]. Furthermore, the open sipes 71 and closed sipes 72 are arranged in each center outer block 32B, extending approximately parallel to the inclination angle of the center outer lug groove 52 within a range of ±3°.

[0047] As shown in Figures 2 and 3, the sipes 80 are provided on each inner shoulder block 32A and each outer shoulder block 32B of each shoulder land portion 32. The sipes 80 are formed in a zigzag shape on the tread surface 15A. The sipes 80 are formed in a straight line in the depth direction (tire diameter direction). The sipes 80 may be formed in a zigzag shape in the depth direction. The sipes 80 include closed sipes 81 and one-sided open sipes 82. The closed sipes 81 have both ends terminated within the block on each inner shoulder block 32A and each outer shoulder block 32B. The closed sipes 81 have a groove width of less than 1.0 [mm]. The closed sipes 81 also have a depth of 4.5 [mm] or more and 12.0 [mm] or less. The single-sided open sipe 82 is provided in each shoulder outer block 32B, extending along the tire width direction, with one end opening to the contact end T and the other end terminating within the shoulder outer block 32B. The single-sided open sipe 82 has a groove width of less than 1.0 mm. The single-sided open sipe 82 also has a depth of 1.0 mm or more and 7.0 mm or less. The closed sipe 81 is arranged in each shoulder inner block 32A, extending approximately parallel to the inclination angle of the shoulder inner lug groove 61 within a range of ±3°. The closed sipe 81 and the single-sided open sipe 82 are also arranged in each shoulder outer block 32B, extending approximately parallel to the inclination angle of the shoulder outer lug groove 62 within a range of ±3°.

[0048] As shown in Figures 2 to 5, the bottom portion 90 is integrally provided, protruding from the groove bottom 20b side of the circumferential main groove 20 toward the tread surface 15A in all of the recesses 20U that widen the groove width W1 of each circumferential main groove 20. The bottom portion 90 has a top portion 90a facing the tread surface 15A and a wall portion 90c rising from the groove bottom 20b of the circumferential main groove 20. The bottom portion 90 is shown with hatching in each plan view to distinguish it from other parts.

[0049] Here, as shown in Figure 5, the circumferential main groove 20 has a groove wall 20c that rises from the groove bottom 20b toward the tread surface 15A toward the opening edge 20a. The groove wall 20c has a bent portion 20cf that is continuous in the tire circumferential direction during its rise. The groove wall 20c includes an opening-side groove wall 20ca on the opening edge 20a side (outer side in the tire radial direction) and a groove bottom-side groove wall 20cb on the groove bottom 20b side (inner side in the tire radial direction), with the bent portion 20cf as the boundary. The groove wall 20c also includes a recessed wall portion 20cc in the area where the recess 20U is provided. The angle αa of the groove bottom-side groove wall 20cb of the circumferential main groove 20 with respect to the tire radial direction is in the range of 0[°] to 10[°]. The angle βa of the opening-side groove wall 20ca of the circumferential main groove 20 with respect to the tire radial direction is in the range of 0[°] to 5[°]. Furthermore, the angle βb of the recessed wall portion 20cc of the circumferential main groove 20 with respect to the tire radial direction is in the range of 0[°] to 5[°].

[0050] As shown in Figures 4 and 5, the top portion 90a of the bottom portion 90 is positioned at the bend 20cf of the circumferential main groove 20. Therefore, the wall portion 90c of the bottom portion 90 is positioned opposite the groove bottom side wall 20cb of the circumferential main groove 20. The wall portion 90c of the bottom portion 90 is also positioned in communication with the groove bottom side wall 20cb of the circumferential main groove 20. Furthermore, the top portion 90a of the bottom portion 90 is provided connected to the recessed wall portion 20cc of the circumferential main groove 20. The angle αb of the wall portion 90c of the bottom portion 90 with respect to the tire radial direction is in the range of 0[°] to 10[°].

[0051] Furthermore, the bottom portion 90 provided in the recess 20U is arranged in multiples with space between them in the tire circumferential direction, and is arranged in the tire width direction in the opposite groove walls 20c of the circumferential main groove 20 in the tire width direction in the recess 20U, and is arranged in the tire width direction in the opposite groove walls 20c of the circumferential main groove 20 in the tire width direction in the opposite groove wall. Also, as shown in Figure 2, the bottom portion 90 (recess 20U) is arranged in a part of the tire circumferential direction in each block 31A, 31B, 32A partitioned by the circumferential main groove 20 and lug groove 50 (60), and is arranged alternately with the protrusion 20P. Note that, as shown in Figure 6, the bottom portion 90 (recess 20U) may be arranged in multiples in the tire circumferential direction with the protrusion 20P in between in each block partitioned by the circumferential main groove 20 and lug groove 50 (60).

[0052] The pneumatic tire 1 of the embodiment is characterized by having, in the tread portion, a plurality of circumferential main grooves 20 extending along the tire circumferential direction and arranged in the tire width direction, a plurality of lug grooves 50, 60 extending along the tire width direction and arranged in the tire circumferential direction and opening into the circumferential main grooves 20, a recess 20U in the groove wall 20c of the circumferential main groove 20 in which the groove width W1 is widened in at least a portion between adjacent lug grooves 50, 60 in the tire circumferential direction, and a bottom upper portion 90 provided in the recess 20U and projecting from the groove bottom 20b side of the circumferential main groove 20 toward the tread surface 15A. Furthermore, the bottom upper portion 90 is characterized in that the wall portion 90c rising from the groove bottom 20b of the circumferential main groove 20 is continuous on the same plane with the groove wall 20c of the circumferential main groove 20 in the portion of the circumferential main groove 20 that does not have a recess 20U, and is arranged on at least one of both groove walls 20c of the circumferential main groove 20 in the area excluding the lug grooves 50, 60.

[0053] According to this pneumatic tire 1, in the area excluding the lug grooves 50 and 60, the bottom portion 90 is provided on at least one of the groove walls 20c of the circumferential main groove 20, thereby preventing foreign objects such as stones from entering the groove bottom 20b of the circumferential main groove 20 and improving resistance to stone drilling. Furthermore, the rigidity of the land portion 30 partitioned by the circumferential main groove 20 and the lug grooves 50 and 60 is increased, improving wear resistance. Moreover, according to this pneumatic tire 1, a recess 20U is provided in the groove wall 20c of the circumferential main groove 20 to form a wider groove width W1, the bottom portion 90 is placed in this recess 20U, and the wall portion 90c of this bottom portion 90 is connected to the groove wall 20c of the circumferential main groove 20 on the same plane, thereby improving drainage and improving wet performance such as braking performance and turning performance on wet road surfaces. As a result, this pneumatic tire 1 can achieve a balance between wet performance, wear resistance, and resistance to stone drilling.

[0054] Furthermore, in the pneumatic tire 1 of the embodiment, as shown in Figure 5, in the cross-section of the circumferential main groove 20 including the bottom upper part 90, the difference between the angles αa and αb of the wall portion 90c of the bottom upper part 90 and the groove wall 20c (groove bottom side groove wall 20cb) of the circumferential main groove 20 facing the wall portion 90c, with respect to the tire radial direction, is approximately equal to 0[°]±3[°].

[0055] With this pneumatic tire 1, the presence of the bottom upper part 90 maintains stone drilling resistance and improves wear resistance. Moreover, with this pneumatic tire 1, the angles αa and αb of the wall portion 90c and groove wall 20c (groove bottom side groove wall 20cb) with respect to the tire radial direction are equal, ensuring drainage and maintaining wet performance, and the rigidity of both land portions 30 separated by the circumferential main groove 20 becomes equal, improving the balance of wear resistance.

[0056] Furthermore, in the pneumatic tire 1 of the embodiment, as shown in Figure 5, in the cross-section of the circumferential main groove 20 including the bottom upper part 90, the angle αb of the wall portion 90c of the bottom upper part 90 with respect to the tire radial direction is greater than the angle βb of the recess wall portion 20cc of the recess 20U in the tread surface 15A from the bottom upper part 90 with respect to the tire radial direction.

[0057] According to this pneumatic tire 1, the angle difference between the wall portion 90c of the upper bottom portion 90 and the recessed wall portion 20cc of the recess 20U ensures that the groove volume on the tread surface 15A side, which is the recess 20U side, is secured, thereby improving wet performance. Furthermore, the increased protrusion of the rubber on the groove bottom 20b side, which is the upper bottom portion 90 side, improves resistance to stone drilling and wear resistance. In order to significantly obtain the above effects, it is preferable that the difference between the angle αb of the wall portion 90c of the upper bottom portion 90 and the angle βb of the recessed wall portion 20cc of the recess 20U be in the range of 5[°]≦αb-βb≦30[°].

[0058] Furthermore, in the pneumatic tire 1 of the embodiment, as shown in Figure 3, the bottom portion 90 is positioned in at least a part of the circumferential range S1 of the tire that is opposite the tire width direction of the openings of the lug grooves 50 and 60 in the circumferential groove 20.

[0059] This pneumatic tire 1 improves resistance to stone drilling by having a bottom portion 90 at the intersection of grooves where stone jamming is likely to occur. Furthermore, this pneumatic tire 1 maintains wear resistance due to the presence of the bottom portion 90, and maintains wet performance because the bottom portion 90 is positioned in the recess 20U. In order to significantly obtain the above effects, the ratio of the tire circumferential length L1 of the bottom portion 90 within the range S1 of the opening range S1 of the lug grooves 50, 60 is preferably in the range of 40[%]≦L1 / S1≦100[%].

[0060] Furthermore, in the pneumatic tire 1 of the embodiment, as shown in Figure 5, in the cross-section of the circumferential main groove 20 including the bottom upper part 90, the groove width W1 including the recess 20U of the circumferential main groove 20 on the tread surface 15A and the groove width W2 of the circumferential main groove 20 at the top 90a of the bottom upper part 90 satisfy the relationship 0.25 ≤ W2 / W1 ≤ 0.75.

[0061] With this pneumatic tire 1, the groove volume on the tread surface 15A side can be secured, maintaining wet performance, and by reducing the groove width W1 on the bottom upper 90 side, stone drilling resistance and wear resistance are improved.

[0062] Furthermore, in the pneumatic tire 1 of the embodiment, as shown in Figure 5, in the cross-section of the circumferential main groove 20 including the bottom upper part 90, the groove depth H1 from the tread surface 15A to the groove bottom 20b of the circumferential main groove 20 and the groove depth H2 from the tread surface 15A to the top 90a of the bottom upper part 90 satisfy the relationship 0.3 ≤ H2 / H1 ≤ 0.7.

[0063] With this pneumatic tire 1, groove volume can be secured on the tread surface 15A side, maintaining wet performance, and the height of the bottom upper part 90 is secured, improving stone drilling resistance and wear resistance.

[0064] Furthermore, in the pneumatic tire 1 of the embodiment, the total length of the bottom upper part 90 in the tire circumferential direction of one groove wall 20c of the circumferential main groove 20 is 40% or more and 60% or less of the total length of the circumferential main groove 20 in the tire circumferential direction.

[0065] With this pneumatic tire 1, the arrangement of the bottom upper portion 90 relative to the circumferential main grooves 20 is balanced, maintaining wet performance while improving stone-drilling resistance and wear resistance.

[0066] Furthermore, in the pneumatic tire 1 of this embodiment, as shown in Figures 2 and 6, the bottom upper portion 90 is alternately arranged on each groove wall 20c of the circumferential main groove 20, with the lug grooves 50 and 60 as the boundary.

[0067] According to this pneumatic tire 1, by positioning the bottom upper part 90 in the recess 20U, wet performance and stone drilling resistance are maintained, while the bottom upper part 90 is alternately positioned on each groove wall 20c, thereby equalizing the rigidity of the land portion 30 and improving wear resistance.

[0068] Furthermore, in the pneumatic tire 1 of the embodiment, as shown in Figure 3, the bottom upper part 90 has a portion (range S2) that overlaps in the tire width direction with both groove walls 20c of the center circumferential main groove 21 located on the tire equatorial plane CL.

[0069] With this pneumatic tire 1, the contact pressure is relatively high near the tire's equatorial plane CL, and the overlap of the bottom portion 90 in the tire width direction at both groove walls 20c of the center circumferential main groove 21 improves resistance to stone drilling. In order to significantly obtain the above effect, the ratio of the range S2 of the overlapping bottom portion 90 in the tire width direction to the tire circumferential length L2 of one bottom portion 90 is preferably in the range of 10[%]≦S2 / L2≦100[%].

[0070] Furthermore, in the pneumatic tire 1 of the embodiment, as shown in Figure 5, in the cross-section of the circumferential main groove 20 including the bottom upper part 90, the top part 90a of the bottom upper part 90 is positioned substantially parallel to the tread surface 15A at an angle of 0[°]±3[°].

[0071] With this pneumatic tire 1, wet performance is maintained by positioning the bottom upper part 90 in the recess 20U, and wear resistance is maintained by positioning the bottom upper part 90. Furthermore, with this pneumatic tire 1, the top 90a of the bottom upper part 90 is approximately parallel to the tread surface 15A, which prevents the intrusion of foreign objects such as stones and improves resistance to stone drilling.

[0072] By the way, in this embodiment, as described above, a pneumatic tire 1 was described as an example of a tire. This 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 this embodiment can be arbitrarily applied to other tires within the scope of what is obvious to those skilled in the art. Other tires include, for example, airless tires and solid tires. [Examples]

[0073] Figures 7 to 10 are charts showing the results of performance tests of the pneumatic tire according to the embodiment. Below, we will describe the performance evaluation tests conducted on a conventional pneumatic tire and the pneumatic tire according to the embodiment. The performance evaluation tests included tests for stone drilling resistance, wet performance, and wear resistance. The test tire was a 205 / 85R16 tire size, mounted on a specified rim, filled to the specified internal pressure, and mounted on a test vehicle (2-D: light truck).

[0074] The stone drilling resistance evaluation test is performed by driving a test vehicle equipped with the test tire on an off-road (unpaved) road for 30 km, measuring the number of stones that reach the bottom of the groove, and calculating the reciprocal of that number. This evaluation is performed using an index evaluation with the conventional example as the baseline (100), and a higher value is preferable.

[0075] The wet performance evaluation test is conducted on a test vehicle equipped with the test tire on a wet test course, measuring the braking distance and calculating its reciprocal. This evaluation is performed using an index evaluation with the conventional example as the baseline (100), and a higher value is preferable.

[0076] The wear resistance performance evaluation test is conducted by measuring the mileage traveled by a test vehicle equipped with the test tire from new until wear is complete (when the wear indicator appears on the tread surface). This evaluation is performed using an index evaluation with the conventional example as the baseline (100), and a higher value is preferable.

[0077] Conventional pneumatic tires have three circumferential main grooves that form four land areas, each land area having a block demarcated by lug grooves, and each circumferential main groove has a bottom portion. However, the circumferential main grooves do not have recesses in the groove walls, and there are portions between the lug grooves where there is no bottom portion.

[0078] The pneumatic tire of the embodiment has four land sections formed by three circumferential main grooves, each land section having a block demarcated by lug grooves, with a bottom portion positioned in the recess of each circumferential main groove, and a bottom portion is always present between the lug grooves.

[0079] As the test results show, the pneumatic tire in this example exhibits improved resistance to stone drilling, wet performance, and wear resistance compared to the conventional example.

[0080] This disclosure includes the following inventions: [Invention 1] In the tread section, there are multiple circumferential main grooves that extend along the tire's circumferential direction and are arranged in the tire's width direction, Lug grooves extending along the tire width direction and arranged in a row in the tire circumferential direction, opening into the circumferential main groove, In the groove wall of the circumferential main groove, a recess is formed in which the groove width is wider in at least a portion between adjacent lug grooves in the tire circumferential direction, A bottom upper portion is provided in the recess and protrudes from the groove bottom side of the circumferential main groove toward the tread surface, Includes, The bottom portion is such that the wall portion rising from the bottom of the circumferential main groove is flush with the groove wall in the portion of the circumferential main groove that does not have the recess, and is positioned on at least one of the two groove walls of the circumferential main groove in the area excluding the lug groove. tire. [Invention 2] In the cross-section of the circumferential main groove including the bottom portion, the difference in angle with respect to the tire radial direction between the wall portion of the bottom portion and the groove wall of the circumferential main groove facing the wall portion is 0[°]±3[°]. The tire described in Invention 1. [Invention 3] In the cross-section of the circumferential main groove including the bottom portion, the angle of the wall portion of the bottom portion with respect to the tire radial direction is greater than the angle of the wall portion of the recess on the tread surface with respect to the tire radial direction. A tire according to invention 1 or 2. [Invention 4] In the circumferential main groove, the bottom portion is positioned in at least a portion of the area of ​​the lug groove opening facing the tire width direction. A tire according to any one of inventions 1 to 3. [Invention 5] In the cross-section of the circumferential main groove including the bottom portion, the groove width W1 including the recess of the circumferential main groove on the tread surface and the groove width W2 of the circumferential main groove at the top of the bottom portion satisfy the relationship 0.25 ≤ W2 / W1 ≤ 0.75. A tire according to any one of inventions 1 to 4. [Invention 6] In the cross-section of the circumferential main groove including the bottom portion, the groove depth H1 from the tread surface to the bottom of the circumferential main groove and the groove depth H2 from the tread surface to the top of the bottom portion satisfy the relationship 0.3 ≤ H2 / H1 ≤ 0.7. A tire according to any one of inventions 1 to 5. [Invention 7] In one groove wall of the circumferential main groove, the total length of the bottom portion in the tire circumferential direction is 40% or more and 60% or less of the total length of the circumferential main groove in the tire circumferential direction. A tire according to any one of inventions 1 to 6. [Invention 8] The aforementioned bottom portion is arranged alternately on each groove wall of the circumferential main groove, with the lug groove as the boundary. A tire according to any one of inventions 1 to 7. [Invention 9] The aforementioned bottom portion has a portion that overlaps in the tire width direction with respect to both groove walls of the circumferential main grooves arranged on the tire's equatorial plane. A tire according to any one of inventions 1 to 8. [Invention 10] In the cross-section of the circumferential main groove including the bottom portion, the top of the bottom portion is positioned at an angle of 0° ± 3° relative to the tread surface. A tire according to any one of inventions 1 to 9. [Explanation of symbols]

[0081] 1. Pneumatic tire (tire) 15A Tread surface 20 Circumferential main groove 20b groove bottom 20c groove wall 20ca Opening side ditch wall 20cb Ditch bottom side wall 20cc recessed wall 50 Center lug groove (lug groove) 60 Shoulder lug groove (lug groove) 90 Bottom top 90a top 90c wall

Claims

1. In the tread section, there are multiple circumferential main grooves that extend along the tire's circumferential direction and are arranged in the tire's width direction, Lug grooves extending along the tire width direction and arranged in a row in the tire circumferential direction, opening into the circumferential main groove, In the groove wall of the circumferential main groove, a recess is formed in which the groove width is wider in at least a portion between adjacent lug grooves in the tire circumferential direction, A bottom upper portion is provided in the recess and protrudes from the groove bottom side of the circumferential main groove toward the tread surface, Includes, The bottom portion is such that the wall portion rising from the bottom of the circumferential main groove is flush with the groove wall in the portion of the circumferential main groove that does not have the recess, and is positioned on at least one of the two groove walls of the circumferential main groove in the area excluding the lug groove. tire.

2. In the cross-section of the circumferential main groove including the bottom portion, the difference in angle with respect to the tire radial direction between the wall portion of the bottom portion and the groove wall of the circumferential main groove facing the wall portion is 0 [°] ± 3 [°]. The tire according to claim 1.

3. In the cross-section of the circumferential main groove including the bottom portion, the angle of the wall portion of the bottom portion with respect to the tire radial direction is greater than the angle of the wall portion of the recess on the tread surface with respect to the tire radial direction. The tire according to claim 1.

4. In the circumferential main groove, the bottom portion is positioned in at least a portion of the area of ​​the lug groove opening facing the tire width direction. The tire according to claim 1.

5. In the cross-section of the circumferential main groove including the bottom portion, the groove width W1 including the recess of the circumferential main groove on the tread surface and the groove width W2 of the circumferential main groove at the top of the bottom portion satisfy the relationship 0.25 ≤ W2 / W1 ≤ 0.

75. The tire according to claim 1.

6. In the cross-section of the circumferential main groove including the bottom portion, the groove depth H1 from the tread surface to the bottom of the circumferential main groove and the groove depth H2 from the tread surface to the top of the bottom portion satisfy the relationship 0.3 ≤ H2 / H1 ≤ 0.

7. The tire according to claim 1.

7. In one groove wall of the circumferential main groove, the total length of the bottom portion in the tire circumferential direction is 40% or more and 60% or less of the total length of the circumferential main groove in the tire circumferential direction. The tire according to claim 1.

8. The aforementioned bottom portion is arranged alternately on each groove wall of the circumferential main groove, with the lug groove as the boundary. The tire according to claim 1.

9. The aforementioned bottom portion has a portion that overlaps in the tire width direction with respect to both groove walls of the circumferential main grooves arranged on the tire's equatorial plane. The tire according to claim 1.

10. In the cross-section of the circumferential main groove including the bottom portion, the top of the bottom portion is positioned at 0° ± 3° relative to the tread surface. The tire according to claim 1.

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