tire

Abstract

To provide a tire that can make both dry performance and wet performance of the tire compatible.SOLUTION: A tire 1 comprises a mounting-direction display part (not shown in a figure) that displays a direction in which the tire is mounted on a vehicle. Further the tire 1 comprises first and second peripheral grooves 21 and 22 (refer to a figure 2) extending intermittently or continuously in a tire circumferential direction. In a state where the tire is mounted on the vehicle, the second peripheral groove 22 is positioned closer to inside in a vehicle width direction than the first peripheral groove 21. A groove volume V1 of the first peripheral groove 21 and a groove volume V2 of the second peripheral groove 22 have a relation: V1<V2.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a tire, and more particularly to a tire capable of achieving both dry performance and wet performance of the tire.

Background Art

[0002] In a racing tire used for both road driving and circuit driving, in order to ensure the wet performance of the tire, it is obligatory to provide circumferential grooves on the tread surface. As a conventional tire adopting such a structure, the technique described in Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a tire capable of achieving both dry performance and wet performance of the tire.

Means for Solving the Problems

[0005] To achieve the above object, a tire according to the present invention is a tire including a mounting direction display portion indicating a tire mounting direction with respect to a vehicle, and includes first and second circumferential grooves extending intermittently or continuously in the tire circumferential direction. In a state where the tire is mounted on the vehicle, the second circumferential groove is located closer to the inner side in the vehicle width direction than the first circumferential groove, and a groove volume V1 of the first circumferential groove and a groove volume V2 of the second circumferential groove have a relationship of V1 < V2. death, The maximum groove depths of the first and second circumferential grooves are in a range of 2.5 [mm] or more and 5.0 [mm] or less. and no other grooves or recesses with an opening area exceeding 40 mm^2 are provided in the tire contact area. . Furthermore, the tire according to the present invention is a tire provided with a mounting direction display portion indicating the tire mounting direction with respect to a vehicle, the tire including first and second circumferential grooves extending intermittently or continuously in the tire circumferential direction, with the second circumferential groove being located closer to the inner side in the vehicle width direction than the first circumferential groove in the vehicle-mounted state of the tire, the groove volume V1 of the first circumferential groove and the groove volume V2 of the second circumferential groove having a relationship of V1 < V2, and the groove area ratio of the tire contact area being in the range of 3.0 [%] or more and 5.0 [%] or less. Furthermore, the tire according to the present invention is a tire provided with a mounting direction display portion indicating the tire mounting direction with respect to a vehicle, the tire including first and second circumferential grooves extending intermittently or continuously in the tire circumferential direction, with the second circumferential groove being located closer to the inner side in the vehicle width direction than the first circumferential groove in the vehicle-mounted state of the tire, the groove volume V1 of the first circumferential groove and the groove volume V2 of the second circumferential groove having a relationship of V1 < V2, and each of the first and second circumferential grooves being composed of a plurality of groove portions that are discontinuous and arranged in a row in the tire circumferential direction, thereby extending intermittently in the tire circumferential direction And there are no other grooves or recesses with an opening area exceeding 40 mm^2 in the tire contact area. .

Advantages of the Invention

[0006] In the tire according to the present invention, since the groove volume V2 of the second circumferential groove on the inner side in the vehicle width direction is larger than the groove volume V1 of the first circumferential groove on the outer side in the vehicle width direction (V1 < V2), the groove volume in the inner region in the vehicle width direction of the tread surface increases, improving the wet performance of the tire. At the same time, the rigidity of the land portion in the outer region in the vehicle width direction increases, improving the traction performance of the tire on a dry road surface. As a result, there is an advantage that the wet performance of the tire and the traction performance on a dry road surface are compatible.

Brief Description of the Drawings

[0007] [Figure 1] FIG. 1 is a cross-sectional view in the tire meridian direction showing the tire according to the embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view showing the tread surface of the tire shown in FIG. 1. [Diagram 3] FIG. 3 is a cross-sectional view showing the circumferential groove shown in FIG. 2. [Figure 4]FIG. 4 is an explanatory diagram showing a modified example of the tire shown in FIG. [Diagram 5] FIG. 5 is an explanatory diagram showing a modified example of the tire shown in FIG. [Figure 6] FIG. 6 is an explanatory diagram showing a modified example of the tire shown in FIG. [Figure 7] FIG. 7 is an explanatory diagram showing a modified example of the tire shown in FIG. [Figure 8] FIG. 8 is an explanatory diagram showing a modified example of the tire shown in FIG. [Figure 9] FIG. 9 is an explanatory diagram showing a modified example of the tire shown in FIG. [Figure 10] FIG. 10 is a table showing the results of performance tests of the tire according to the embodiment of the present invention. [Figure 11] FIG. 11 is a table showing the results of performance tests of the tire according to the embodiment of the present invention. [Figure 12] FIG. 12 is an explanatory diagram showing the conventional test tire shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the embodiments. The components of the embodiments include those that can be substituted and are obvious substitutes while maintaining the identity of the invention. The multiple modified examples described in the embodiments can be arbitrarily combined within the scope of what is obvious to those skilled in the art.

[0009] [tire] Fig. 1 is a cross-sectional view in the tire meridian direction showing a tire according to an embodiment of the present invention. The figure shows a cross-sectional view of one side region in the tire radial direction. In this embodiment, a pneumatic radial tire for racing used both on public roads and on circuits will be described as an example of a tire.

[0010] In the figure, the tire meridian cross section is defined as a cross section of the tire cut by a plane including the tire rotation axis (not shown). The tire equatorial plane CL is defined as a plane that passes through the midpoint of the tire section width measurement points specified by JATMA and is perpendicular to the tire rotation axis. The tire width direction is defined as a direction parallel to the tire rotation axis, and the tire radial direction is defined as a direction perpendicular to the tire rotation axis.

[0011] Additionally, the vehicle width direction inner side and vehicle width direction outer side are defined as the directions relative to the vehicle width direction when the tire is mounted on a vehicle. Additionally, the left and right regions bounded by the tire equatorial plane are defined as the vehicle width direction outer region and the vehicle width direction inner region, respectively. Additionally, the tire is provided with a mounting direction indicator (not shown) that indicates the tire mounting direction on the vehicle. The mounting direction indicator is formed, for example, by a mark or unevenness provided on the sidewall portion of the tire. For example, ECER30 (Article 30 of the Economic Commission for Europe Regulation) requires that a vehicle mounting direction indicator be provided on the sidewall portion that is on the vehicle width direction outer side when mounted on the vehicle.

[0012] The tire 1 has an annular structure centered on the tire rotation axis, and includes a pair of bead cores 11, 11, a pair of bead fillers 12, 12, a carcass layer 13, a belt layer 14, a tread rubber 15, a pair of sidewall rubbers 16, 16, a pair of rim cushion rubbers 17, 17, and an inner liner 18 (see Figure 1).

[0013] The pair of bead cores 11, 11 are formed by winding one or more steel bead wires in an annular manner in multiple layers, and are embedded in the bead portions to form the cores of the left and right bead portions. The pair of bead fillers 12, 12 are disposed on the outer periphery of the pair of bead cores 11, 11 in the tire radial direction, respectively, to reinforce the bead portions.

[0014] The carcass layer 13 has a single-layer structure consisting of one carcass ply or a multi-layer structure consisting of multiple carcass plies stacked together, and is toroidally stretched between the left and right bead cores 11, 11 to form the tire framework. Both ends of the carcass layer 13 are wrapped around and secured to the outside in the tire width direction so as to envelop the bead cores 11 and the bead fillers 12. The carcass ply of the carcass layer 13 is formed by covering multiple carcass cords made of steel or organic fiber material (e.g., aramid, nylon, polyester, rayon, etc.) with coating rubber and rolling them, and has a cord angle (defined as the inclination angle of the carcass cords in the longitudinal direction with respect to the tire circumferential direction) of 80 degrees or more and 100 degrees or less.

[0015] 1, the carcass layer 13 has a multi-layer structure formed by laminating two carcass plies 131 and 132. However, the present invention is not limited to this, and the carcass layer 13 may be formed by laminating three or more carcass plies, or may have a single-layer structure formed by one carcass ply (not shown).

[0016] The belt layer 14 is formed by laminating a plurality of belt plies 141 to 143, and is disposed by being wound around the outer periphery of the carcass layer 13. The belt plies 141 to 143 each include a pair of cross belts 141, 142 and a pair of belt covers 143, 143.

[0017] The pair of cross belts 141, 142 are formed by covering a plurality of belt cords made of steel or organic fiber material with coating rubber and rolling them, and have a cord angle of 15 degrees or more and 55 degrees or less in absolute value. The pair of cross belts 141, 142 have cord angles (defined as the inclination angle of the belt cords in the longitudinal direction with respect to the tire circumferential direction) of opposite signs, and are layered with the longitudinal directions of the belt cords crossing each other (so-called cross-ply structure). The pair of cross belts 141, 142 are layered and arranged on the outer side of the carcass layer 13 in the tire radial direction.

[0018] The belt cover 143 is configured by covering a belt cover cord made of steel or organic fiber material with a coating rubber, and has a cord angle of 0 degrees or more and 10 degrees or less in absolute value. The belt cover 143 is, for example, a strip material configured by covering one or more belt cover cords with a coating rubber, and is configured by winding this strip material spirally around the outer circumferential surface of the cross belts 141 and 142 several times in the tire circumferential direction. In the configuration of FIG. 1, a pair of belt covers 143, 143 are arranged to cover the left and right edge portions of the cross belts 141 and 142 from the outside in the tire radial direction. However, this is not limited to this, and a single belt cover 143 may be arranged to cover the entire area of ​​the cross belts 141 and 142 (not shown).

[0019] The tread rubber 15 is disposed on the tire radial outer periphery of the carcass layer 13 and the belt layer 14 to form the tire tread portion. A pair of sidewall rubbers 16, 16 are disposed on the tire widthwise outer sides of the carcass layer 13 to form the left and right sidewall portions. A pair of rim cushion rubbers 17, 17 extend from the tire radial inner sides of the left and right bead cores 11, 11 and the turn-up portions of the carcass layer 13 to the tire widthwise outer sides to form the rim fitting surfaces of the bead portions. The inner liner 18 is an air permeation prevention layer disposed on the tire cavity surface and covers the carcass layer 13, suppressing oxidation due to exposure of the carcass layer 13 and preventing leakage of air filled in the tire.

[0020] 1, the tire section height SH and the tire total width SW have a relationship of 0.20≦SH / SW≦0.70, and preferably a relationship of 0.30≦SH / SW≦0.60. The tire ground contact width TW and the tire total width SW have a relationship of 0.90≦TW / SW≦0.98, and preferably a relationship of 0.94≦TW / SW≦0.96. The width Wb of the wide cross belt 141 and the tire ground contact width TW have a relationship of 0.98≦Wb / TW≦1.10, and preferably a relationship of 1.00≦Wb / TW≦1.05.

[0021] The tire section height SH is half the distance between the tire outer diameter and the rim diameter, and is measured with the tire mounted on a specified rim, with a specified internal pressure applied, and in an unloaded state.

[0022] The total tire width SW is measured as the straight-line distance between the sidewalls (including all parts such as patterns and lettering on the side of the tire) when the tire is mounted on a specified rim, pressurized to the specified internal pressure, and unloaded.

[0023] The tire contact width TW is measured as the maximum straight-line distance in the axial direction of the tire at 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, and placed perpendicular to a flat plate in a stationary state and subjected to a load corresponding to a specified load.

[0024] The tire ground contact edge T is defined as the widest position in the axial direction of the tire at 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, and placed perpendicular to a flat plate in a stationary state and subjected to a load corresponding to a specified load.

[0025] The width of the belt ply is the distance between the left and right ends of each belt ply in the tire rotational axis direction, and is measured with the tire mounted on a specified rim, with a specified internal pressure applied, and in an unloaded state.

[0026] The specified rim refers to the "applicable rim" specified by JATMA, the "design rim" specified by TRA, or the "measuring rim" specified by ETRTO. The specified internal pressure refers to the "maximum air pressure" specified by JATMA, the maximum value of the "tire load limits at various cold inflation pressures" specified by TRA, or the "inflation pressures" specified by ETRTO. The specified load refers to the "maximum load capacity" specified by JATMA, the maximum value of the "tire load limits at various cold inflation pressures" specified by TRA, or the "load capacity" specified by ETRTO. However, in JATMA, for passenger car tires, the specified internal pressure is 180 kPa, and the specified load is 88% of the maximum load capacity.

[0027] [Tread surface] Fig. 2 is a plan view showing the tread surface of the tire shown in Fig. 1. Fig. 3 is a cross-sectional view showing the circumferential groove 21 (22) shown in Fig. 2. In these drawings, the tire circumferential direction refers to the direction around the tire rotation axis. Also, the symbol T is the tire ground contact edge, and the dimension symbol TW is the tire ground contact width.

[0028] 2, the tire 1 has on its tread surface first and second circumferential grooves 21, 22. In addition, as will be described later, the tire 1 does not have on its tread surface any other circumferential grooves or dimples.

[0029] The circumferential grooves 21, 22 are required to extend intermittently or continuously in the tire circumferential direction. In the configuration of Fig. 2, the first and second circumferential grooves 21, 22 each include a plurality of groove portions 211, 221 that are discontinuously arranged in a line in the tire circumferential direction, and thus extend intermittently in the tire circumferential direction.

[0030] Specifically, the multiple grooves 211 constituting the first circumferential groove 21 are discontinuously arranged in a row in the tire circumferential direction along a predetermined imaginary line X1 parallel to the tire equatorial plane CL. The distance of the center of gravity of all the grooves 211 to the imaginary line X1 (dimension symbols omitted in the drawing) is within a range of less than 0.5% of the tire ground contact width TW. In other words, a group of grooves 211 that satisfy the above distance condition to the predetermined imaginary line X1 constitutes one row of the first circumferential groove 21. The imaginary line X1 is defined as the groove center line of the first circumferential groove 21.

[0031] Similarly, the multiple grooves 221 constituting the second circumferential groove 22 are discontinuously arranged in a row in the tire circumferential direction along a predetermined imaginary line X2 parallel to the tire equatorial plane CL. The distance of the center of gravity of all the grooves 221 to the imaginary line X2 (dimension symbols omitted in the figure) is within a range of less than 0.5% of the tire ground contact width TW. In other words, a group of grooves 221 that satisfy the above distance condition to the predetermined imaginary line X2 constitutes one row of the second circumferential groove 22. The imaginary line X2 is defined as the groove center line of the second circumferential groove 22.

[0032] The distance of the center of gravity of groove portion 211 and the distance of the center of gravity of groove portion 221 are measured with the tire mounted on a specified rim, a specified internal pressure applied, and in an unloaded state.

[0033] The maximum groove width W1 of the first circumferential groove 21 and the maximum groove width W2 of the second circumferential groove 22 have the relationship of 0.020≦W1 / TW≦0.080 and 0.020≦W2 / TW≦0.080 with respect to the tire ground contact width TW. The maximum groove widths W1 and W2 of the first and second circumferential grooves 21 and 22 are in the range of 4.0 mm to 16 mm, preferably 6.0 mm to 10 mm. The maximum groove widths W1 and W2 of the first and second circumferential grooves 21 and 22 have the relationship of 0.90≦W2 / W1≦1.10, preferably 0.95≦W2 / W1≦1.05.

[0034] The maximum groove width W1;W2 of the circumferential grooves 21;22 is measured as the distance between the opposing groove walls at the groove opening when the tire is mounted on a specified rim and inflated to a specified internal pressure and in an unloaded state. When the circumferential grooves 21;22 extend discontinuously in the tire circumferential direction as shown in Figure 2, the maximum groove width W1;W2 is measured as the maximum groove width of all groove portions 211;221 constituting one circumferential groove 21;22.

[0035] In addition, in FIG. 3, the maximum groove depth H1 of the first circumferential groove 21 and the maximum groove depth H2 of the second circumferential groove 22 are in the range of 2.5 mm or more and 5.0 mm or less, and preferably in the range of 2.8 mm or more and 4.0 mm or less.

[0036] The maximum groove depth H21;H22 of the circumferential grooves 21;22 is measured as the distance from the tread surface to the groove bottom when the tire is mounted on a specified rim, inflated to a specified internal pressure, and in a no-load state. In the case of a structure having partial unevenness or sipes at the groove bottom, the groove depth is measured excluding these.

[0037] 3, the maximum groove depths H1 and H2 of the first and second circumferential grooves 21 and 22 are in the range of 60% to 85% and preferably 63% to 70% of the gauge Gr of the tread rubber 15 on the groove centerlines of the circumferential grooves 21 and 22. The gauge Gr of the tread rubber 15 is in the range of 30% to 60% and preferably 35% to 55% of the total gauge Gt of the tread portion on the groove centerlines of the circumferential grooves 21 and 22.

[0038] The gauge Gr of the tread rubber 15 is measured as the distance from the tread profile to the outer circumferential surface of the outermost belt layer 142, and does not include the gauge of the coat rubber (not shown) of the outermost belt layer 142.

[0039] The total gauge Gt of the tread portion is measured as the distance from the tread profile to the inner surface of the tire, and does not include the gauge of partial unevenness formed on the tread surface or the inner surface of the tire.

[0040] Also, in Figure 2, the groove area A1 of the first circumferential groove 21 and the groove area A2 (not shown) of the second circumferential groove 22 have a relationship with the area Sa of the tire contact area of ​​0.015≦A1 / Sa≦0.100 and 0.015≦A2 / Sa≦0.100, and preferably have a relationship of 0.015≦A1 / Sa≦0.020 and 0.015≦A2 / Sa≦0.020.

[0041] The groove area is the opening area of ​​the groove on the tread surface, and is measured at the contact surface between the tire and a flat plate when the tire is mounted on a specified rim, a specified internal pressure is applied, the tire is placed perpendicular to a flat plate in a stationary state, and a load corresponding to a specified load is applied. In addition, when the circumferential grooves 21;22 extend discontinuously in the tire circumferential direction as shown in Figure 2, the groove areas A1;A2 of the circumferential grooves 21;22 are calculated as the sum of the opening areas of the multiple groove portions 211;221 that constitute the circumferential grooves 21;22.

[0042] The area Sa of the tire contact area is the area of ​​the entire tread surface defined by the left and right tire contact edges T, and is defined as an area including both grooves and land portions.

[0043] 2, as described above, each of the first and second circumferential grooves 21, 22 is composed of a plurality of groove portions 211, 221 that are discontinuously arranged in a line in the tire circumferential direction. The opening areas of the groove portions 211, 221 that constitute the first and second circumferential grooves 21, 22 are each in the range of 200 mm^2 to 340 mm^2, and preferably in the range of 240 mm^2 to 300 mm^2.

[0044] It is also preferable that the tire 1 does not have any other grooves or recesses having an opening area exceeding 40 [mm^2], preferably exceeding 20 [mm^2], i.e., grooves or recesses other than the circumferential grooves 21, 22, in the tire ground contact area. In other words, the tire ground contact area may have recesses or grooves having an opening area smaller than the above condition, such as wear indicators (not shown) consisting of small holes, in the areas other than the areas where the circumferential grooves 21, 22 are arranged. The groove area ratio of the tire ground contact area is in the range of 3.0 [%] to 5.0 [%], preferably in the range of 3.2 [%] to 3.8 [%].

[0045] For example, in the configuration of FIG. 2, the tire ground contact area includes only the first and second circumferential grooves 21, 22, and a wear indicator (not shown) is formed at the bottom of the predetermined circumferential grooves 21, 22. Moreover, the area other than the area where the circumferential grooves 21, 22 are arranged has a plain tread surface without grooves or sipes. Therefore, in the configuration of FIG. 2, the groove area in the entire tire ground contact area is equal to the sum of the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22. Moreover, the groove area ratio of the tire ground contact area is in the range of 0.030≦(A1+A2) / Sa≦0.200.

[0046] The groove area ratio is defined as the ratio of the total area of ​​grooves arranged in a given region to the area of ​​that region.

[0047] In the configuration of FIG. 2, the pitch length P1 of the groove portion 211 of the first circumferential groove 21 and the pitch length P2 of the groove portion 221 of the second circumferential groove 22 have the relationships 0.030≦P1 / TL≦0.060 and 0.030≦P2 / TL≦0.060 with respect to the tire circumference TL (not shown).

[0048] The tire circumference TL is measured as the maximum circumference of the tread surface when the tire is mounted on a specified rim, pressurized to a specified internal pressure, and under no load.

[0049] Also, in FIG. 2 , the maximum circumferential length L1 of groove portion 211 of first circumferential groove 21 and the maximum circumferential length L2 of groove portion 221 of second circumferential groove 22 have a relationship of 0.30≦L1 / P1≦0.60 and 0.30≦L2 / P2≦0.60 with respect to the pitch length P1 of groove portion 211 of first circumferential groove 21 and the pitch length P2 of groove portion 221 of second circumferential groove 22, and preferably have a relationship of 0.45≦L1 / P1≦0.55 and 0.45≦L2 / P2≦0.55.

[0050] The maximum circumferential lengths L1; L2 of the groove portions 211; 221 of the circumferential grooves 21; 22 are measured as the circumferential distance at the groove opening when the tire is mounted on a specified rim and inflated to a specified internal pressure in an unloaded state.

[0051] In addition, in FIG. 2 , the maximum circumferential length L1 of groove portion 211 of first circumferential groove 21 and the maximum circumferential length L2 of groove portion 221 of second circumferential groove 22 have a relationship of 2.00≦L1 / W1≦8.00 and 2.00≦L2 / W2≦8.00 with respect to the maximum groove width W1 of first circumferential groove 21 and the maximum groove width W2 of second circumferential groove 22, respectively, and preferably have a relationship of 4.00≦L1 / W1≦6.00 and 4.00≦L2 / W2≦6.00.

[0052] In addition, in Figure 2, the phase difference φ between the groove portion 211 of the first circumferential groove 21 and the groove portion 221 of the second circumferential groove 22 has a relationship of 0.25≦φ / P1≦0.75 with respect to the pitch length P1 of the groove portion 211 of the first circumferential groove 21, and preferably has a relationship of 0.40≦φ / P1≦0.50.

[0053] For example, in the configuration of FIG. 2, the grooves 211 and 221 have a rectangular or elliptical shape that is elongated in the tire circumferential direction. The grooves 211 of the first circumferential groove 21 and the grooves 221 of the second circumferential groove 22 are arranged in a staggered manner in the tire circumferential direction. Specifically, the pitch number of the grooves 211 of the first circumferential groove 21 and the pitch number of the grooves 221 of the second circumferential groove 22 are set to be the same, and the maximum circumferential length L1 of the grooves 211 of the first circumferential groove 21 and the maximum circumferential length L2 of the grooves 221 of the second circumferential groove 22 are set to 50[%] of the pitch length P1 of the grooves 211 of the first circumferential groove 21 and the pitch length P2 of the grooves 221 of the second circumferential groove 22. The phase difference φ between the grooves 211 of the first circumferential groove 21 and the grooves 221 of the second circumferential groove 22 is set to about 50[%] of the pitch length P1 of the grooves 211 of the first circumferential groove 21.

[0054] [Difference in groove volume of circumferential groove] In this tire 1, as shown in Fig. 2, the first circumferential groove 21 is disposed in an area on the outer side in the vehicle width direction, with the tire equatorial plane CL as a boundary, and the second circumferential groove 22 is disposed in an area on the inner side in the vehicle width direction. In addition, a distance D1 from the tire equatorial plane CL to the groove center line X1 of the first circumferential groove 21 and a distance D2 from the tire equatorial plane CL to the groove center line X2 of the second circumferential groove 22 are approximately equal. Therefore, the first and second circumferential grooves 21, 22 are disposed at approximately the same position with respect to the tire equatorial plane CL. In addition, the distance D1 of the first circumferential groove 21 and the distance D2 of the second circumferential groove 22 have a relationship of 0.90 ≦ D2 / D1 ≦ 1.10, and preferably have a relationship of 0.95 ≦ D2 / D1 ≦ 1.05.

[0055] 2, the distances D1 and D2 from the tire equatorial plane CL to the groove centerlines X1 and X2 of the first and second circumferential grooves 21 and 22 have the relationship of 0.05≦D1 / TW≦0.45 and 0.05≦D2 / TW≦0.45 with respect to the tire ground contact width TW, and preferably have the relationship of 0.10≦D1 / TW≦0.25 and 0.10≦D2 / TW≦0.25. The distance Dg in the tire width direction between the groove centerline X1 of the first circumferential groove 21 and the groove centerline X2 of the second circumferential groove 22 has the relationship of 0.10≦Dg / TW with respect to the tire ground contact width TW, and preferably has the relationship of 0.20≦Dg / TW. The upper limit of the ratio Dg / TW is not particularly limited, but is restricted by other conditions.

[0056] The distances D1, D2, and Dg are measured with the tire mounted on a specified rim and a specified internal pressure applied thereto, and in a no-load state.

[0057] Also, the groove volume V1 of the first circumferential groove 21 and the groove volume V2 of the second circumferential groove 22 have a relationship of V1 < V2. Therefore, the first and second circumferential grooves 21, 22 have different groove volumes V1, V2. Further, the groove volume V1 of the first circumferential groove 21 and the groove volume V2 of the second circumferential groove 22 have a relationship of 1.11 ≦ V2 / V1 ≦ 2.00, preferably 1.20 ≦ V2 / V1 ≦ 1.80.

[0058] The groove volume is measured as the volume of the region surrounded by the tread surface and the groove wall surface. Also, when the circumferential grooves 21; 22 extend intermittently in the tire circumferential direction as shown in FIG. 2, the groove volumes V1, V2 of the circumferential grooves 21; 22 are calculated as the sum of the volumes of a plurality of groove portions 211; 221 constituting the circumferential grooves 21; 22.

[0059] In the above configuration, since the groove volume V2 of the second circumferential groove 22 on the inner side in the vehicle width direction is larger than the groove volume V1 of the first circumferential groove 21 on the outer side in the vehicle width direction (V1 < V2), the groove volume of the inner region in the vehicle width direction of the tread surface increases, improving the wet performance of the tire. At the same time, the rigidity of the land portion in the outer region in the vehicle width direction increases, improving the traction performance of the tire on a dry road surface. Thereby, the wet performance of the tire and the traction performance on a dry road surface are made compatible.

[0060] For example, in the configuration of FIG. 2, the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22 have a relationship of A1 < A2. Also, the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22 have a relationship of 1.11 ≦ A2 / A1 ≦ 2.00, preferably 1.20 ≦ A2 / A1 ≦ 1.80.

[0061] More specifically, the maximum groove width W1 of the first circumferential groove 21 and the maximum groove width W2 of the second circumferential groove 22 have a relationship of W1 < W2. Also, the maximum groove width W1 of the first circumferential groove 21 and the maximum groove width W2 of the second circumferential groove 22 have a relationship of 1.11 ≦ W2 / W1, preferably 1.20 ≦ W2 / W1. The upper limit of the ratio W2 / W1 is not particularly limited, but is restricted by other conditions.

[0062] Also, in FIG. 3, the maximum depth H1 of the first circumferential groove 21 and the maximum depth H2 of the second circumferential groove 21 are substantially equal, having a relationship of 0.90 ≦ H2 / H1 ≦ 1.10, preferably 0.95 ≦ H2 / H1 ≦ 1.05.

[0063] Also, in the configuration of FIG. 2, the pitch length P1 of the groove portion 211 of the first circumferential groove 21 and the pitch length P2 of the groove portion 221 of the second circumferential groove 22 have a relationship of 0.90 ≦ P1 / P2 ≦ 1.10, preferably 0.95 ≦ P1 / P2 ≦ 1.05.

[0064] Also, in the configuration of FIG. 2, the maximum circumferential direction length L1 of the groove portion 211 of the first circumferential groove 21 and the maximum circumferential direction length L2 of the groove portion 221 of the second circumferential groove 22 have a relationship of 0.90 ≦ L2 / L1 ≦ 1.10, preferably 0.95 ≦ L2 / L1 ≦ 1.05.

[0065] [Modification Example 1] FIGS. 4 and 5 are explanatory views showing a modification of the tire described in FIG. 2. In these figures, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

[0066] In the configuration of FIG. 2, as described above, since the maximum groove width W1 of the first circumferential groove 21 and the maximum groove width W2 of the second circumferential groove 22 have a relationship of W1 < W2, a relationship of A1 < A2 between the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22 is formed.

[0067] In contrast, in the configuration of FIG. 4, since the pitch length P1 of the groove portion 211 of the first circumferential groove 21 and the pitch length P2 of the groove portion 221 of the second circumferential groove 22 have the relationship of P2 < P1, a relationship of A1 < A2 is formed between the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22. Specifically, the pitch length P1 of the groove portion 211 of the first circumferential groove 21 and the pitch length P2 of the groove portion 221 of the second circumferential groove 22 have the relationship of 1.11 ≦ P1 / P2, and preferably have the relationship of 1.20 ≦ P1 / P2. The upper limit of the ratio P1 / P2 is not particularly limited, but is restricted by other conditions.

[0068] Also, in the configuration of FIG. 4, the maximum groove width W1 of the first circumferential groove 21 and the maximum groove width W2 of the second circumferential groove 22 are substantially equal, having a relationship of 0.90 ≦ W2 / W1 ≦ 1.10, and preferably having a relationship of 0.95 ≦ W2 / W1 ≦ 1.05.

[0069] Also, the maximum depth H1 of the first circumferential groove 21 and the maximum depth H2 of the second circumferential groove 21 (see FIG. 3) are substantially equal, having a relationship of 0.90 ≦ H2 / H1 ≦ 1.10, and preferably having a relationship of 0.95 ≦ H2 / H1 ≦ 1.05.

[0070] Also, in FIG. 4, the maximum circumferential direction length L1 of the groove portion 211 of the first circumferential groove 21 and the maximum circumferential direction length L2 of the groove portion 221 of the second circumferential groove 22 have a relationship of 0.90 ≦ L2 / L1 ≦ 1.10, and preferably have a relationship of 0.95 ≦ L2 / L1 ≦ 1.05.

[0071] On the other hand, in the configuration of FIG. 5, since the maximum circumferential direction length L1 of the groove portion 211 of the first circumferential groove 21 and the maximum circumferential direction length L2 of the groove portion 221 of the second circumferential groove 22 have the relationship of L1 < L2, a relationship of A1 < A2 is formed between the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22. Specifically, the maximum circumferential direction length L1 of the groove portion 211 of the first circumferential groove 21 and the maximum circumferential direction length L2 of the groove portion 221 of the second circumferential groove 22 have the relationship of 1.11 ≦ L2 / L1, and preferably have the relationship of 1.20 ≦ L2 / L1. The upper limit of the ratio L2 / L1 is not particularly limited, but is restricted by other conditions.

[0072] [Modification Example 2] Figures 6 and 7 are explanatory diagrams showing modified examples of the tire shown in Figure 2. In these figures, the same components as those in Figure 2 are given the same reference numerals, and the description thereof will be omitted.

[0073] 2, the first circumferential groove 21 includes a plurality of grooves 211 arranged at a predetermined pitch length P1 around the entire circumference of the tire, and the second circumferential groove 22 includes a plurality of grooves 221 arranged at a predetermined pitch length P2 around the entire circumference of the tire. The first and second grooves 211, 221 are arranged in a staggered pattern in the tire circumferential direction with a predetermined phase difference φ. This configuration is preferable in that it can improve wet performance while maintaining the tire's traction performance.

[0074] In contrast, in the configuration of FIG. 6, the first circumferential groove 21 has a first groove unit U1 consisting of three or more groove portions 211 arranged at a predetermined pitch length P1 in the tire circumferential direction, and the first groove units U1 are arranged at a predetermined pitch length P1' in the tire circumferential direction. Similarly, the second circumferential groove 22 has a second groove unit U2 consisting of three or more groove portions 221 arranged at a predetermined pitch length P2 in the tire circumferential direction, and the second groove units U2 are arranged at a predetermined pitch length P2' in the tire circumferential direction. The first and second groove units U1 and U2 are arranged in a staggered pattern in the tire circumferential direction with a predetermined phase difference φ'. This configuration is preferable in that it can improve the traction performance while maintaining the wet performance of the tire.

[0075] 6, the pitch length P1' of the first groove unit U1 and the pitch length P2' of the second groove unit U2 have the relationship of 0.10≦P1' / TL≦0.30 and 0.10≦P2' / TL≦0.30 with respect to the tire circumference TL (not shown). The pitch length P1' of the first groove unit U1 and the pitch length P2' of the second groove unit U2 have the relationship of 0.90≦P1' / P2'≦1.10, and preferably have the relationship of 0.95≦P1' / P2'≦1.05.

[0076] In addition, in FIG. 6, the maximum circumferential length L1' of the first groove unit U1 and the maximum circumferential length L2' of the second groove unit U2 have the relationships of 0.050 ≦ L1' / TL ≦ 0.100 and 0.050 ≦ L2' / TL ≦ 0.100 with respect to the tire circumferential length TL (not shown). Also, the maximum circumferential length L1' of the first groove unit U1 and the maximum circumferential length L2' of the second groove unit U2 have the relationship of 0.90 ≦ L2' / L1' ≦ 1.10, and preferably have the relationship of 0.95 ≦ L2' / L1' ≦ 1.05.

[0077] In addition, in FIG. 6, the maximum circumferential length L1' of the first groove unit U1 and the maximum circumferential length L2' of the second groove unit U2 have the relationships of 0.30 ≦ L1' / P1' ≦ 0.60 and 0.30 ≦ L2' / P2' ≦ 0.60 with respect to the pitch length P1' of the first groove unit U1 and the pitch length P2' of the second groove unit U2, and preferably have the relationships of 0.45 ≦ L1' / P1' ≦ 0.55 and 0.45 ≦ L2' / P2' ≦ 0.55.

[0078] In addition, in FIG. 6, the phase difference φ' between the first groove unit U1 and the second groove unit U2 has the relationship of 0.25 ≦ φ' / P1' ≦ 0.75 with respect to the pitch length P1' of the first groove unit U1, and preferably has the relationship of 0.40 ≦ φ' / P1' ≦ 0.50.

[0079] In addition, in the configuration of FIG. 6, similar to the case of FIG. 2, since the maximum groove width W1 of the first circumferential groove 21 and the maximum groove width W2 of the second circumferential groove 22 have the relationship of W1 < W2, the relationship of A1 < A2 between the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22 is formed.

[0080] On the other hand, in the configuration of FIG. 7, in the configuration of FIG. 6, since the number N1 of the groove portions 211 constituting the first groove unit U1 is smaller than the number N2 of the groove portions 221 constituting the second groove unit U2 (N1 < N2), the relationship of A1 < A2 between the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22 is formed. Also, in FIG. 7, the number N1 of the groove portions 211 constituting the first groove unit U1 is 2, but it may be at least 1 or more.

[0081] [Modification Example 3] FIG. 8 is an explanatory view showing a modification of the tire described in FIG. 2. In these figures, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

[0082] In the configuration of FIG. 2, as described above, each of the first and second circumferential grooves 21 and 22 is composed of a plurality of groove portions 211 and 221 that are discontinuous and arranged in a row in the tire circumferential direction. In such a configuration, it is preferable in that the contact area of the tire increases and the traction performance can be improved while maintaining the wet performance of the tire.

[0083] On the other hand, in the configuration of FIG. 8, each of the first and second circumferential grooves 21 and 22 extends continuously in the tire circumferential direction. In such a configuration, compared with the configuration of FIG. 2, it is preferable in that the groove area of the tire increases and the wet performance can be improved while maintaining the traction performance of the tire.

[0084] [Modification Example 4] FIG. 9 is an explanatory view showing a modification of the tire described in FIG. 2. In these figures, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

[0085] In the configuration of FIG. 2, as shown in FIG. 3, the groove depths H1 and H2 of the first and second circumferential grooves 21 and 22 are set to be the same, while the relationship A1 < A2 between the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22 on the tread surface is formed, whereby the relationship V1 < V2 between the groove volume V1 of the first circumferential groove 21 and the groove volume V2 of the second circumferential groove 22 is formed.

[0086] However, not limited thereto, the relationship between the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22 is set to be substantially the same, while as shown in FIG. 9, the groove depths H1 and H2 of the first and second circumferential grooves 21 and 22 in the groove depth direction have the relationship H1 < H2, whereby the relationship V1 < V2 between the groove volume V1 of the first circumferential groove 21 and the groove volume V2 of the second circumferential groove 22 may be formed.

[0087] [Effect] As described above, this tire 1 includes a mounting direction display portion (not shown) that indicates the tire mounting direction with respect to the vehicle. Further, the tire 1 includes first and second circumferential grooves 21 and 22 that extend intermittently or continuously in the tire circumferential direction (see FIG. 2). Also, in the vehicle-mounted state of the tire, the second circumferential groove 22 is located closer to the inner side in the vehicle width direction than the first circumferential groove 21. Further, the groove volume V1 of the first circumferential groove 21 and the groove volume V2 of the second circumferential groove 22 have a relationship of V1 < V2.

[0088] In such a configuration, since the groove volume V2 of the second circumferential groove 22 on the inner side in the vehicle width direction is larger than the groove volume V1 of the first circumferential groove 21 on the outer side in the vehicle width direction (V1 < V2), the groove volume in the inner region in the vehicle width direction of the tread surface increases, improving the wet performance of the tire. At the same time, the rigidity of the land portion in the outer region in the vehicle width direction increases, improving the traction performance of the tire on a dry road surface. As a result, there is an advantage that the wet performance of the tire and the traction performance on a dry road surface are compatible.

[0089] Further, in this tire 1, the groove volume V1 of the first circumferential groove 21 and the groove volume V2 of the second circumferential groove 22 have a relationship of 1.11 ≦ V2 / V1 ≦ 2.00 (see FIG. 2). As a result, there is an advantage that the improvement effects on the wet performance and traction performance of the tire due to the difference in the groove volumes V1 and V2 of the circumferential grooves 21 and 22 described above can be appropriately obtained.

[0090] Further, in this tire 1, the maximum groove width W1 of the first circumferential groove 21 and the maximum groove width W2 of the second circumferential groove 22 have a relationship of 0.020 ≦ W1 / TW ≦ 0.080 and 0.020 ≦ W2 / TW ≦ 0.080 with respect to the tire contact width TW (see FIG. 2). Due to the above lower limit, there is an advantage that the drainage performance of the circumferential grooves 21 and 22 is ensured. Also, due to the above upper limit, there is an advantage that the deterioration of the traction performance caused by the circumferential grooves 21 and 22 becoming overly wide is suppressed.

[0091] Further, in this tire 1, the maximum groove depths H1 and H2 of the first and second circumferential grooves 21 and 22 are in the range of 2.5 [mm] or more and 5.0 [mm] or less. As a result, there is an advantage that the maximum groove depths H1 and H2 of the circumferential grooves 21 and 22 are optimized.

[0092] Further, in this tire 1, the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22 have a relationship of 0.015 ≦ A1 / Sa ≦ 0.100 and 0.015 ≦ A2 / Sa ≦ 0.100 with respect to the area Sa of the tire contact region. Thereby, there is an advantage that the groove areas A1 and A2 of the circumferential grooves 21 and 22 are optimized.

[0093] Also, in this tire 1, there are no other grooves or recesses having an opening area exceeding 40 [mm^2] in the tire contact region (see FIG. 2). Thereby, there is an advantage that the contact area of the tire is ensured and the above-described effect of improving the traction performance of the tire is appropriately ensured.

[0094] Further, in this tire 1, the groove area ratio of the tire contact region is in the range of 3.0 [%] or more and 5.0 [%] or less. Thereby, there is an advantage that the traction of the tire, particularly in a race tire, is ensured.

[0095] Also, in this tire 1, the groove area A1 of the first circumferential groove 21 and the groove area A2 of the second circumferential groove 22 have a relationship of A1 < A2 (see FIGS. 2 and 4 to 8). Thereby, there is an advantage that the relationship V1 < V2 between the groove volume V1 of the first circumferential groove 21 and the groove volume V2 of the second circumferential groove 22 described above is efficiently formed.

[0096] Also, in this tire 1, the maximum depth H1 of the first circumferential groove 21 and the maximum depth H2 of the second circumferential groove 22 have a relationship of H1 < H2 (see FIG. 9). Thereby, there is an advantage that the relationship V1 < V2 between the groove volume V1 of the first circumferential groove 21 and the groove volume V2 of the second circumferential groove 22 described above is efficiently formed.

[0097] Also, in this tire 1, the first circumferential groove 21 is disposed in a region outside the vehicle width direction with the tire equatorial plane CL as a boundary, and the second circumferential groove 22 is disposed in a region inside the vehicle width direction (see FIG. 2). With such a configuration, there is an advantage that the uneven wear resistance of the tire is improved as compared with the configuration of FIG. 4.

[0098] In addition, in the tire 1, the first and second circumferential grooves 21, 22 each include a plurality of groove portions 211, 221 that are discontinuously arranged in a line in the tire circumferential direction, and thus extend intermittently in the tire circumferential direction (see Figs. 2, 4 to 7). This configuration has the advantage of improving the traction performance of the tire compared to the configuration in Fig. 8.

[0099] In the tire 1, the first and second circumferential grooves 21, 22 each extend continuously in the tire circumferential direction (see FIG. 8). This configuration has the advantage of improving the wet performance of the tire compared to the configuration in FIG.

[0100] In addition, in this tire 1, the tire section height SH and the tire total width SW have a relationship of 0.20≦SH / SW≦0.70, and the tire contact width TW and the tire total width SW have a relationship of 0.90≦TW / SW≦0.98 (see FIG. 1). This has the advantage that the aspect ratio SH / SW and tire contact width TW of the tire are optimized.

[0101] The tire 1 includes a pair of bead cores 11, 11, a carcass layer 13 stretched across the pair of bead cores 11, 11, a pair of cross belts 141, 142 arranged on the outer periphery of the carcass layer 13, and a tread rubber 15 arranged radially outside the cross belts 141, 142 (see FIG. 1). The width Wb of the wider cross belt of the pair of cross belts 141, 142 (the cross belt 141 on the inner diameter side in FIG. 1) has a relationship of 0.98≦Wb / TW≦1.10 with the tire contact width TW. This has the advantage of ensuring the durability of the tire appropriately.

[0102] The tire 1 includes a pair of bead cores 11, 11, a carcass layer 13 stretched across the pair of bead cores 11, 11, a pair of cross belts 141, 142 arranged on the outer periphery of the carcass layer 13, and a tread rubber 15 arranged radially outward of the cross belts 141, 142 (see FIG. 1). The gauge Gr of the tread rubber 15 is in the range of 30% to 60% of the total gauge Gt of the tread portion on the groove center lines of the first and second circumferential grooves 21, 22 (see FIG. 3). This has the advantage of optimizing the gauge Gr of the tread rubber 15. EXAMPLES

[0103] 10 and 11 are tables showing the results of performance tests of the tire according to the embodiment of the present invention, and FIG. 12 is an explanatory view showing the conventional test tire shown in FIG.

[0104] In this performance test, several types of test tires were evaluated for (1) dry performance and (2) wet performance. Test tires with tire size P205 / 50R15 84W were mounted on JATMA-specified rims and installed on all wheels of a test vehicle, a four-wheeled passenger car weighing 990 kg. The test tires were pressurized to 160 kPa in cold conditions and 220 kPa in warm conditions.

[0105] (1) In the evaluation of dry performance, the test vehicle completes four laps of a specified circuit of 3.7 km in clear skies with a road surface temperature of 18°C ​​and an air temperature of 28°C, and the lap time is measured. The best lap time is then used to perform an index evaluation with the conventional example as the standard (100). The higher the value, the better.

[0106] (2) In the evaluation regarding wet performance, the test vehicle runs four laps on a predetermined circuit with a circumference of 3.7 [km] and a water depth of 1 [mm], and its lap time is measured. Then, the best lap time is used to conduct an index evaluation based on the conventional example (100). In this evaluation, the larger the numerical value, the more preferable. Also, if the evaluation is 99 or more, it can be said that the performance is maintained appropriately.

[0107] The test tire of the example has the configurations shown in FIGS. 1 to 3. The first circumferential groove 21 is arranged in the region on the outer side in the vehicle width direction with the tire equatorial plane CL as the boundary, and the second circumferential groove 22 is arranged in the region on the inner side in the vehicle width direction. Also, each of the first and second circumferential grooves 21, 22 is composed of a plurality of groove portions 211, 221 that are discontinuous and arranged in a row in the tire circumferential direction. Further, the outer diameter of the tire is 586 [mm], the tire cross-sectional height SH is 103 [mm], the total width SW of the tire is 216 [mm], the tire contact width TW is 202 [mm], and the belt width Wb of the wide cross belt 142 is 203 [mm]. Also, the gauge Gr of the tread rubber 15 on the groove center lines X1, X2 of the circumferential grooves 21, 22 is in the range of 4.0 [mm] to 4.7 [mm], and the total gauge Gt of the tread portion is in the range of 10 [mm] to 11 [mm]. Also, the groove widths W1, W2 of the first and second circumferential grooves 21, 22 have a relationship of W1 < W2, and the groove depths H1, H2 are H1 = H2 = 3.3 [mm]. Also, the distances D1, D2 of the circumferential grooves 21, 22 have a relationship of D1 / TW = D2 / TW = 0.25 with respect to the tire contact width TW.

[0108] The test tire of the conventional example has the configuration described in FIG. 12, and is different from the test tire of Example 1 in that the first and second circumferential grooves continuously extend in the tire circumferential direction and in that the groove widths and groove volumes of the first and second circumferential grooves are the same.

[0109] As shown by the test results, it can be seen that the test tire of the example achieves both dry performance and wet performance of the tire.

Explanation of Signs

[0110] 1 tire; 11 bead core; 12 bead filler; 13 carcass layer; 131, 132 carcass ply; 14 belt layer; 141, 142 cross belt; 143 belt cover; 15 tread rubber; 16 sidewall rubber; 17 rim cushion rubber; 18 inner liner; 21 first circumferential groove; 211 groove portion; 22 second circumferential groove; 221 groove portion

Claims

1. A tire having a mounting direction indicator that indicates the tire mounting direction relative to a vehicle, The tire has first and second circumferential grooves extending discontinuously or continuously in a circumferential direction, When the tire is mounted on a vehicle, the second circumferential groove is located more inward in a vehicle width direction than the first circumferential groove, a groove volume V1 of the first circumferential groove and a groove volume V2 of the second circumferential groove have a relationship of V1<V2, The maximum groove depth of the first and second circumferential grooves is in the range of 2.5 mm to 5.0 mm, and A tire characterized in that it does not have any other grooves or recesses in the tire contact area having an opening area exceeding 40 [mm^2].

2. The tire according to claim 1 , wherein a groove volume V1 of the first circumferential groove and a groove volume V2 of the second circumferential groove satisfy a relationship of 1.11≦V2 / V1≦2.

00.

3. 3. The tire according to claim 1, wherein a maximum groove width W1 of the first circumferential groove and a maximum groove width W2 of the second circumferential groove satisfy the relationships of 0.020≦W1 / TW≦0.080 and 0.020≦W2 / TW≦0.080 with respect to a tire ground contact width TW.

4. The tire according to any one of claims 1 to 3, wherein the groove area A1 of the first circumferential groove and the groove area A2 of the second circumferential groove have a relationship of 0.015≦A1 / Sa≦0.100 and 0.015≦A2 / Sa≦0.100 with respect to the area Sa of the tire ground contact area.

5. 5. The tire according to claim 1, wherein a groove area ratio of the tire ground contact region is in the range of 3.0% or more and 5.0% or less.

6. The tire according to any one of claims 1 to 5, wherein a groove area A1 of the first circumferential groove and a groove area A2 of the second circumferential groove satisfy a relationship of A1<A2.

7. The tire according to any one of claims 1 to 6, wherein a maximum depth H1 of the first circumferential groove and a maximum depth H2 of the second circumferential groove satisfy a relationship of H1<H2.

8. The tire according to any one of claims 1 to 7, wherein the first circumferential groove is disposed in an outer region in the vehicle width direction bounded by the tire equatorial plane, and the second circumferential groove is disposed in an inner region in the vehicle width direction.

9. The tire according to any one of claims 1 to 8, wherein each of the first and second circumferential grooves is composed of a plurality of groove portions that are discontinuously arranged in a line in the tire circumferential direction, thereby extending intermittently in the tire circumferential direction.

10. The tire according to any one of claims 1 to 8, wherein each of the first and second circumferential grooves extends continuously in the tire circumferential direction.

11. The tire according to any one of claims 1 to 10, wherein the tire section height SH and the tire total width SW have a relationship of 0.20≦SH / SW≦0.70, and the tire ground contact width TW and the tire total width SW have a relationship of 0.90≦TW / SW≦0.

98.

12. A tire comprising: a pair of bead cores; a carcass layer disposed around the pair of bead cores; a pair of cross belts disposed on an outer periphery of the carcass layer; and a tread rubber disposed radially outward of the cross belts; The tire according to any one of claims 1 to 11, wherein a width Wb of the wider cross belt of the pair of cross belts satisfies a relationship of 0.98≦Wb / TW≦1.10 with respect to a tire ground contact width TW.

13. A tire comprising: a pair of bead cores; a carcass layer disposed around the pair of bead cores; a pair of cross belts disposed on an outer periphery of the carcass layer; and a tread rubber disposed radially outward of the cross belts; The tire according to any one of claims 1 to 12, wherein the gauge of the tread rubber is in the range of 30% to 60% of the total gauge of the tread portion on the groove center lines of the first and second circumferential grooves.

14. A tire having a mounting direction indicator that indicates the tire mounting direction relative to a vehicle, The tire has first and second circumferential grooves extending discontinuously or continuously in a circumferential direction, When the tire is mounted on a vehicle, the second circumferential groove is located more inward in a vehicle width direction than the first circumferential groove, A groove volume V1 of the first circumferential groove and a groove volume V2 of the second circumferential groove have a relationship of V1 < V2, and A tire characterized in that a groove area ratio of the tire ground contact region is in the range of 3.0% or more and 5.0% or less.

15. A tire having a mounting direction indicator that indicates the tire mounting direction relative to a vehicle, The tire has first and second circumferential grooves extending discontinuously or continuously in a circumferential direction, When the tire is mounted on a vehicle, the second circumferential groove is located more inward in a vehicle width direction than the first circumferential groove, A groove volume V1 of the first circumferential groove and a groove volume V2 of the second circumferential groove have a relationship of V1 < V2, and Each of the first and second circumferential grooves is made of a plurality of groove portions that are discontinuously arranged in a line in the tire circumferential direction, and thus extends intermittently in the tire circumferential direction; and A tire characterized in that it does not have any other grooves or recesses in the tire contact area having an opening area exceeding 40 [mm^2].

Images