Tire

Abstract

To provide a tire which can improve snow traction performance.SOLUTION: A side block 4 of a tire comprises: a long block part 41 which is arranged overlapping with each of a first shoulder block and a second shoulder block in a tire radial direction; a short block part 42 which is arranged overlapping with each of the second shoulder block 322 and the long block part 41 in the tire radial direction; and an L-shaped groove 43 which penetrates through the side block 4 to partition the long block part 41 and the short block part 42. The L-shaped groove 43 connects a radial direction groove part 431 with a circumferential groove part 432 in an L-shaped state. An angle θ32 of inclination of the circumferential groove part 432 relative to the tire radial direction is within the range: 45°≤θ32≤135°.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a tire, and more particularly to a tire capable of improving snow traction performance. [Background technology]

[0002] In recent years, tires for crossover SUVs (Sport Utility Vehicles) have been provided with side blocks having grooves in the buttress portion of the tire in order to improve the snow traction performance of the tire. The technology described in Patent Document 1 is known as a conventional tire employing such a structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-121876 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in view of the above, and has an object to provide a tire that can improve snow traction performance. [Means for solving the problem]

[0005] In order to achieve the above object, a tire according to the present invention is a tire comprising first and second shoulder lug grooves that open into a tire buttress portion and are arranged alternately in the tire circumferential direction, first and second shoulder blocks that are defined by the first and second shoulder lug grooves and are arranged alternately in the tire circumferential direction, and side blocks formed in the tire buttress portion, wherein the side blocks each include a long block that is arranged to overlap the first and second shoulder blocks, respectively, as viewed in the tire radial direction, and a long block that is arranged to overlap the second shoulder block and the long block portion, as viewed in the tire radial direction. and an L-shaped groove that penetrates the side blocks to partition the long block portion and the short block portion, the L-shaped groove being formed by connecting in an L shape a radial groove portion that extends in the tire radial direction and connects to an edge portion on the outer side of the side block in the tire radial direction, and a circumferential groove portion that extends in the tire circumferential direction and opens into one edge portion of the side block in the tire circumferential direction, and an inclination angle θ32 of the circumferential groove portion with respect to the tire radial direction is in the range of 45°≦θ32≦135°, with the bending direction of the L-shaped groove toward the inside in the tire radial direction being taken as positive. Effect of the Invention

[0006] In the tire according to the present invention, (1) the side blocks have long block portions arranged to overlap the first and second shoulder blocks as viewed in the tire radial direction, which has the advantage of improving the snow traction performance of the tire compared to a tire having only short side blocks. Also, (2) the side blocks have L-shaped grooves formed by connecting a radial groove portion and a circumferential groove portion in an L shape, which has the advantage of increasing the edge components of the side blocks in the tire circumferential direction and tire radial direction, which has the advantage of improving the snow traction performance of the tire. Furthermore, (3) the circumferential groove portion opens to one edge portion of the side block in the tire circumferential direction, which has the advantage of improving the snow removal performance from the L-shaped groove. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view in the tire meridian direction showing a tire according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged cross-sectional view showing a shoulder portion of the tire shown in FIG. [Diagram 3] FIG. 3 is a perspective view showing a shoulder portion of the tire shown in FIG. [Figure 4] FIG. 4 is a plan view showing a buttress portion of the tire shown in FIG. [Diagram 5] FIG. 5 is an explanatory diagram showing the side block shown in FIG. [Figure 6] FIG. 6 is an explanatory diagram showing the side block shown in FIG. [Figure 7] FIG. 7 is a table showing the results of performance tests of the tire according to the embodiment of the present invention. [Figure 8] FIG. 8 is a table showing the results of performance tests of the tire according to the embodiment of the present invention. 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 1 according to an embodiment of the present invention. The figure shows a cross-sectional view of one side region in the tire radial direction. The figure also shows a pneumatic radial tire for a crossover SUV 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] 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, and a pair of rim cushion rubbers 17, 17 (see Figure 1).

[0012] 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.

[0013] 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.

[0014] The belt layer 14 is formed by laminating a plurality of belt plies 141 to 144, and is disposed by being wound around the outer periphery of the carcass layer 13. The belt plies 141 to 144 each include a pair of cross belts 141, 142 and a plurality of belt covers 143, 144.

[0015] 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.

[0016] The belt cover 143 is configured by covering a belt cover cord made of steel or organic fiber material with 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 made by covering one or more belt cover cords with coating rubber, and is configured by winding this strip material spirally multiple times in the tire circumferential direction around the outer circumferential surfaces of the cross belts 141 and 142. The belt cover 143 is disposed to cover the entire area of ​​the cross belts 141 and 142.

[0017] The tread rubber 15 is disposed on the outer periphery of the carcass layer 13 and the belt layer 14 in the tire radial direction to form the tread portion of the tire. A pair of sidewall rubbers 16, 16 are disposed on the outer sides of the carcass layer 13 in the tire width direction to form left and right sidewall portions. A pair of rim cushion rubbers 17, 17 extend from the inner side in the tire radial direction of the left and right bead cores 11, 11 and the turned-up portions of the carcass layer 13 to the outer side in the tire width direction to form the rim fitting surface of the bead portion.

[0018] The tire 1 also has on its tread surface a plurality of circumferential main grooves 2 and a plurality of land portions 3 defined by these circumferential main grooves 2. In the configuration of Fig. 1, the tire 1 has four circumferential main grooves 2 and five rows of land portions.

[0019] The circumferential main groove 2 is a groove that is required to display a wear indicator as specified by JATMA, and has a groove width of 2.5 mm or more and 15.0 mm or less, and a groove depth of 8.0 mm or more and 12.0 mm or less.

[0020] The groove width is measured as the distance between the opposing groove walls at the groove opening when the tire is mounted on a specified rim, inflated to a specified internal pressure, and in an unloaded state. In a configuration in which the groove opening has a notch or chamfer, the groove width is measured at the intersection of an extension of the tread surface and an extension of the groove wall in a cross-sectional view parallel to the groove width direction and the groove depth direction.

[0021] The groove depth is measured as the distance from the tread surface to the bottom of the groove when the tire is mounted on a specified rim, inflated to a specified internal pressure, and under no load. In the case of a tire having partial unevenness or sipes at the bottom of the groove, the groove depth is measured excluding these.

[0022] The specified rim refers to the "standard rim" specified by JATMA, the "design rim" specified by TRA, or the "measuring rim" specified by ETRTO. The specified internal pressure refers to the "maximum air pressure" specified by JATMA, the maximum value 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 at the specified internal pressure.

[0023] [Shoulder land area] Figures 2 and 3 are an enlarged cross-sectional view (Figure 2) and a perspective view (Figure 3) showing the shoulder portion of the tire 1 shown in Figure 1. In these figures, Figure 2 shows a cross-sectional view of the region from the shoulder main groove 2s to the tire maximum width position A of the tire 1, and Figure 3 shows a perspective view of the tire buttress portion.

[0024] In Fig. 1, a pair of circumferential main grooves 2s, 2s located at the outermost sides in the tire width direction are defined as shoulder main grooves, and land portions 3s, 3s on the outer sides in the tire width direction defined by these shoulder main grooves 2s, 2s are defined as shoulder land portions. The pair of shoulder land portions 3s, 3s has tire ground contact edges T on its tread surface.

[0025] 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.

[0026] As shown in FIGS. 2 and 3, the shoulder land portion 3s includes first and second shoulder lug grooves 311, 312, and first and second shoulder blocks 321, 322 defined by these shoulder lug grooves 311, 312.

[0027] The first and second shoulder lug grooves 311, 312 open to the shoulder main groove 2s at one end, extend in the tire width direction, intersect with the tire ground contact edge T, and have the other end in the tire buttress portion. The first and second shoulder lug grooves 311, 312 are arranged alternately in the tire circumferential direction. The first and second shoulder lug grooves 311, 312 are distinguished by their positional relationship with the side block 4 described later. Therefore, the first and second shoulder lug grooves 311, 312 may have the same structure or different structures from each other.

[0028] The first and second shoulder lug grooves 311, 312 have a groove width (dimension symbols omitted in the figure) of 4.0 mm or more and 9.0 mm or less and a groove depth H31 (see FIG. 2) of 6.0 mm or more and 10.5 mm or less. The groove depth H31 of the shoulder lug grooves 311, 312 is in the range of 0.70≦H31 / Hm≦0.90 relative to the groove depth Hm (see FIG. 2) of the shoulder main groove 2s. Therefore, the shoulder lug grooves 311, 312 are distinguished from sipes that are closed when the tire contacts the ground in that they function as grooves that are open when the tire contacts the ground.

[0029] The groove depth H31 of the shoulder lug grooves 311, 312 is measured as the maximum groove depth in the tire contact area when the tire is mounted on a specified rim, inflated to a specified internal pressure, and in an unloaded state.

[0030] The first and second shoulder blocks 321, 322 extend from the shoulder main groove 2s to the tire buttress portion. The first and second shoulder blocks 321, 322 are alternately arranged in the tire circumferential direction to form a row of blocks. The first and second shoulder blocks 321, 322 are distinguished by their positional relationship with the side blocks 4, which will be described later. Therefore, the first and second shoulder blocks 321, 322 may have the same structure or different structures from each other.

[0031] In addition, the first and second shoulder blocks 321, 322 may have, for example, sipes formed on the tread surface, chamfered or notched portions formed in the edge portions, decorative shallow grooves formed in the buttress portions, etc. (not shown).

[0032] [Side Block] FIG. 4 is a plan view showing a buttress portion of the tire 1 shown in FIG.

[0033] This tire 1 is equipped with side blocks 4 in the buttress portion, as shown in Figures 2 and 3. The side blocks 4 are convex portions that protrude from the side profile of the tire to the outer surface of the tire and have the main functions of (1) protecting the tire side portions from external damage and enhancing the cut resistance of the tire, and (2) improving the snow removal performance of the buttress portion and enhancing the snow traction performance of the tire.

[0034] The buttress portion is defined as a non-ground contact area formed at the connection between the profile of the tread portion and the profile of the sidewall portion, and constitutes the outer sidewall surface in the tire width direction of the shoulder land portion 3s.

[0035] The side profile is a contour line that approximates the outer surface of the sidewall from the bead portion to the buttress portion as a smooth arc in a cross-sectional view taken along the tire meridian direction, and is defined excluding partial unevenness formed on the tire side portion (such as side block 4 and mold split position M in FIG. 4).

[0036] The tire profile is the outline of the tire in a cross-sectional view taken along the tire meridian direction, and is measured using a laser profiler, such as a tire profile measuring device (manufactured by Matsuo Corporation).

[0037] 2, the height Hs of the side blocks 4 is in the range of 0.5 mm≦Hs≦3.0 mm, and preferably in the range of 1.0 mm≦Hs≦2.0 mm. The lower limit ensures that the side blocks 4 improve the snow performance of the tire. The upper limit prevents the side blocks 4 from being too large, thereby ensuring the ground contact characteristics of the tire.

[0038] The maximum height Hs of the side block 4 is measured as the maximum value of the protruding height from the side profile to the top surface of the side block 4.

[0039] As shown in Fig. 4, a plurality of side blocks 4 are arranged at a predetermined interval in the tire circumferential direction. For example, in the configuration of Fig. 4, a plurality of units, each of which includes one side block 4 and first and second shoulder blocks 321, 322, are arranged around the entire tire circumference. Therefore, the pitch length Ps of the side block 4 is equal to the pitch length Pb of the first and second shoulder blocks 321, 322. The total number of side blocks 4 is half the total number of the first and second shoulder blocks 321, 322.

[0040] 4, the circumferential length Ls of the side block 4 is in the range of 0.80≦Ls / Pb≦1.00, and preferably in the range of 0.85≦Ls / Pb≦0.95, relative to the pitch length Pb of the first and second shoulder blocks 321, 322. The above lower limit ensures the circumferential length Ls of the side block 4, thereby ensuring the snow traction performance of the side block 4. The above upper limit also suppresses a decrease in the degree of freedom of tire deformation caused by the circumferential length Ls of the side block 4 being excessively large, thereby ensuring the ground contact characteristics of the tire.

[0041] The circumferential length Ls of the side block 4 is the maximum extension length in the tire circumferential direction of the side block 4, which is a set of a long block portion 41 and a short block portion 42 described later, and is measured in a plan view of the buttress portion.

[0042] As shown in Figs. 2 to 4, the tire 1 has a mold split position M in the buttress portion, and the side blocks 4 extend from the mold split position M toward the inside in the tire radial direction.

[0043] The mold split position M is defined as a position corresponding to the connection of the split mold of the tire molding die. At this mold split position M, a rib-like protrusion having a width of about 2 mm to 3 mm is formed by residual rubber that is caught during tire vulcanization molding. Specifically, the split mold (not shown) is composed of a first molding die that advances and retreats in the tire radial direction to form the tread portion, and left and right second molding dies that advance and retreat in the tire axial direction to form the side portions, so that the mold split position M has a rib-like structure that extends in the tire circumferential direction.

[0044] However, this is not limited to the above, and in a configuration (not shown) in which the split mold of the tire molding die is split into two in the tire width direction, the mold split position M is not formed in the tire side portion but is formed on the tread surface. In this case, the mold split position M in Figures 2 to 4 is omitted.

[0045] 2 and 4, the radial width Ws of the side blocks 4 is in the range of 0.05≦Ws / SH≦0.25 relative to the tire cross-sectional height SH (see FIG. 1), and preferably in the range of ◆0.10≦Ws / SH≦0.20. The above lower limit ensures the radial width Ws of the side blocks 4, thereby ensuring the snow traction performance of the side blocks 4. The above upper limit also suppresses a decrease in the degree of freedom of tire deformation caused by the side blocks 4 being excessively large, thereby ensuring the ground contact characteristics of the tire.

[0046] The radial width Ws of the side block 4 is measured as the maximum radial extension length of the side block 4 when the tire is mounted on a specified rim, pressurized to a specified internal pressure, and in an unloaded state.

[0047] 2, the radial distance Ds from the tire maximum width position A to the radially inner end of the side block 4 is in the range of 0.05≦Ds / SH≦0.25, preferably 0.10≦Ds / SH≦0.20, relative to the tire cross-sectional height SH (see FIG. 1). The lower limit prevents a decrease in the degree of freedom of tire deformation and ensures the ground contact characteristics of the tire. The upper limit ensures the radial width Ws of the side block 4 and ensures the snow traction performance of the side block 4.

[0048] [Long block section, short block section and L-shaped groove] Figures 5 and 6 are explanatory diagrams showing the side block 4 shown in Figure 4. In these figures, Figure 5 is an enlarged view showing one side block 4, and Figure 6 is an enlarged view showing an L-shaped groove of the side block 4.

[0049] As shown in FIG. 5, the side block 4 includes a long block portion 41, a short block portion 42, and an L-shaped groove 43.

[0050] The long block portion 41 is a block portion that is long in the tire circumferential direction and is disposed so as to overlap both the first and second shoulder blocks 321, 322 when viewed in the tire radial direction (i.e., when projected in the tire radial direction). This improves the snow traction performance of the tire compared to a configuration (not shown) that includes only short side blocks.

[0051] The circumferential length L1 of the long block portion 41 is in the range of 0.60≦L1 / Ls≦1.00 relative to the circumferential length Ls of the side block, and preferably in the range of 0.80≦L1 / Ls≦0.90.

[0052] The circumferential length L1 of the long block portion 41 is measured as the maximum extension length of the long block portion 41 in the tire circumferential direction.

[0053] Furthermore, the radial width W1 of the long block portion 41 is in the range of 0.25≦W1 / L1≦0.45 relative to the circumferential length L1 of the long block portion 41, and preferably in the range of 0.30≦W1 / L1≦0.40. This optimizes the aspect ratio of the long block portion 41, ensuring that the long block portion 41 improves snow traction performance.

[0054] The radial width W1 of the long block portion 41 is measured as the maximum extension length of the long block portion 41 in the tire radial direction.

[0055] 5, the tire 1 has a mold split position M in the buttress portion, and a radially outer edge portion of the long block portion 41 is connected to the mold split position M. In this case, the connection length Le1 of the long block portion 41 to the mold split position M is in the range of 0.35≦Le1 / L1≦0.55 with respect to the circumferential length L1 of the long block portion 41, and preferably in the range of 0.40≦Le1 / L1≦0.50.

[0056] The connection length Le1 of the long block portion 41 is measured as the length in the tire circumferential direction along the parting position M of the mold.

[0057] 5, the first shoulder block 321 extends to the mold dividing position M. A radially outer edge portion of the long block portion 41 is disposed opposite a radially inner edge portion of the first shoulder block 321 across the mold dividing position M. A connection length Le1 of the long block portion 41 at the mold dividing position M, relative to a circumferential length Lb1 of the first shoulder block 321 at the mold dividing position M, is in a range of 0.90≦Le1 / Lb1≦1.10, and preferably in a range of 0.95≦Le1 / Lb1≦1.05.

[0058] The connection length Le1 of the long block portion 41 at the parting position M of the mold is measured as the arrangement distance between the first and second shoulder lug grooves 311, 312 which define the long block portion 41.

[0059] For example, in the configuration of Figure 5, the radially outer edge portion of the long block portion 41 is aligned in the tire circumferential direction with the radially inner edge portion of the first shoulder block 321, so that the long block portion 41 extends the first shoulder block 321 in the tire radial direction through the mold split position M.

[0060] 5, the long block portion 41 has an edge shape that tapers from the mold split position M toward the tire radially inward. Specifically, a radial groove portion 431 of an L-shaped groove 43 described later is inclined toward the tire radially inward in the bending direction of the L-shaped groove 43, and the other circumferential edge portion of the long block portion 41 is inclined in the opposite direction to the radial groove portion 431. As a result, the circumferential length of the long block portion 41 is expanded from the mold split position M toward the tire radially inward. This improves the snow traction effect of the side block 4.

[0061] In addition, in FIG. 5, the distance W1' in the tire radial direction from one end point of the measurement point of the circumferential length L1 of the long block portion 41, specifically the end point on the opposite side of the L-shaped groove 43, to the mold split position M, relative to the radial width W1 of the long block portion 41, is in the range of 0.40≦W1' / W1≦0.70, and preferably in the range of 0.50≦W1' / W1≦0.60.

[0062] 6, the width Wt of the long block portion 41 at the apex Q of the bent shape of the L-shaped groove 43 described later is in the range of 0.10≦Wt / W1, and preferably in the range of 0.15≦Wt / W1, relative to the radial width W1 of the long block portion 41. This ensures the cut resistance of the tire side portion by the long block portion 41. There is no particular upper limit to the ratio Wt / W1, but it is subject to other conditions.

[0063] 5, the short block portion 42 is a block portion that is shorter in the tire circumferential direction than the long block portion 41, and is disposed so as to overlap the second shoulder block 322 and the long block portion 41 when viewed in the tire radial direction. Specifically, the short block portion 42 is disposed between the second shoulder block 322 and the long block portion 41.

[0064] Moreover, the circumferential length L2 of the short block portion 42 is in the range of 0.35≦L2 / Ls≦0.55 with respect to the circumferential length Ls of the side block 4, and preferably in the range of 0.40≦L2 / Ls≦0.50. Moreover, the circumferential length L2 of the short block portion 42 is in the range of 0.30≦L2 / L1≦0.60 with respect to the circumferential length L1 of the long block portion 41, and preferably in the range of 0.40≦L2 / L1≦0.50. The above lower limit ensures the circumferential length L2 of the short block portion 42, and ensures the improvement of snow traction performance by the short block portion 42. The above upper limit suppresses deterioration of the ground contact characteristics of the tire caused by the short block portion 42 being excessively large.

[0065] The circumferential length L2 of the short block portion 42 is measured as the maximum extension length of the short block portion 42 in the tire circumferential direction.

[0066] 6, the circumferential length L2' of the edge portion on the radially inner side of the short block portion 42 defined by a circumferential groove portion 432 described later is in the range of 0.70≦L2' / L2≦0.90, and preferably in the range of 0.75≦L2' / L2≦0.85, relative to the circumferential length L2 (see FIG. 5) of the short block portion 42. The lower limit ensures that the short block portion 42 improves snow traction performance, and the upper limit improves snow removal performance in the L-shaped groove 43.

[0067] Moreover, the radial width W2 of the short block portion 42 is in the range of 0.20≦W2 / L2≦0.50 relative to the circumferential length L2 of the short block portion 42, and preferably in the range of 0.30≦W2 / L2≦0.40. This optimizes the aspect ratio of the short block portion 42, thereby ensuring the improvement of snow traction performance by the short block portion 42 and the snow removal function in the L-shaped groove 43. Moreover, the radial width W2 of the short block portion 42 is in the range of 0.30≦W2 / W1≦0.60 relative to the radial width W1 of the long block portion 41, and preferably in the range of 0.40≦W2 / W1≦0.50. This ensures a balanced arrangement between the long block portion 41 and the short block portion 42.

[0068] The radial width W2 of the short block portion 42 is measured as the maximum extension length of the short block portion 42 in the tire radial direction.

[0069] 5, the tire 1 has a mold split position M in the buttress portion, and the radially outer edge portion of the short block portion 42 is connected to the mold split position M. In this case, the connection length Le2 of the short block portion 42 to the mold split position M is in the range of 0.80≦Le2 / L2≦1.00 with respect to the circumferential length L2 of the short block portion 42, and preferably in the range of 0.85≦Le2 / L2≦0.95.

[0070] The connection length Le2 of the short block portion 42 is measured as the length in the tire circumferential direction along the parting position M of the mold.

[0071] 5, the second shoulder block 322 extends to the mold dividing position M. A radially outer edge portion of the short block portion 42 is disposed opposite a radially inner edge portion of the second shoulder block 322 across the mold dividing position M. A connection length Le2 of the short block portion 42 at the mold dividing position M, relative to a circumferential length Lb2 of the second shoulder block 322 at the mold dividing position M, is in a range of 0.90≦Le2 / Lb2≦1.10, and preferably in a range of 0.95≦Le2 / Lb2≦1.05.

[0072] The connection length Le2 of the short block portion 42 at the parting position M of the mold is measured as the arrangement distance between the first and second shoulder lug grooves 311, 312 which define the short block portion 42.

[0073] For example, in the configuration of Figure 5, the radially outer edge portion of the short block portion 42 is aligned in the tire circumferential direction with the radially inner edge portion of the second shoulder block 322, so that the short block portion 42 extends the second shoulder block 322 in the tire radial direction through the mold split position M.

[0074] 5, the short block portion 42 has an edge shape that tapers from the mold split position M toward the tire radially inward. Specifically, a radial groove portion 431 of an L-shaped groove 43 described later is inclined in the bending direction of the L-shaped groove 43 toward the tire radially inward, and the other circumferential edge portion of the short block portion 42 is inclined in the opposite direction to the radial groove portion 431. As a result, the circumferential length of the short block portion 42 is reduced from the mold split position M toward the tire radially inward. This improves the snow removal function of the L-shaped groove 43 described later.

[0075] 5, the L-shaped groove 43 has an L-shape in a plan view of the buttress portion, and is a groove that penetrates the side block 4 to divide the long block portion 41 and the short block portion 42. Specifically, the L-shaped groove 43 divides the long block portion 41 at the edge portion on the reflective angle side (back side) of the L-shape, and divides the short block portion 42 at the edge portion on the apex angle side (ventral side) of the L-shape. This L-shaped groove 43 is formed by connecting a radial groove portion 431 and a circumferential groove portion 432 in an L shape. In this configuration, the edge components of the side block 4 in the tire circumferential direction and tire radial direction are increased by the L-shaped groove 43, improving the snow traction performance of the tire.

[0076] The radial groove portion 431 extends in the tire radial direction and connects to an edge portion on the outer side in the tire radial direction of the side block 4. In the configuration in Fig. 5, since the tire 1 has a mold split position M, the radial groove portion 431 extends to and terminates at the mold split position M.

[0077] 5 and 6, the radial groove portion 431 is disposed on an extension line of the second shoulder lug groove 312. This improves snow discharge from the second shoulder lug groove 312 to the radial groove portion 431.

[0078] 6, the groove width W31 of the radial groove portion 431 is in the range of 3.0 [mm] ≦ W31 ≦ 7.0 [mm], preferably in the range of 3.5 [mm] ≦ W31 ≦ 6.5 [mm]. The groove width W31' (dimension symbols omitted in the figure) of the radial groove portion 431 at the radially outer end is in the range of 0.90 ≦ W31' / Wg ≦ 1.10 with respect to the groove width Wg of the second shoulder lug groove 312 at the tire radially inner end, preferably in the range of 0.95 ≦ W31' / Wg ≦ 1.05. This also promotes snow removal from the second shoulder lug groove 312 to the radial groove portion 431.

[0079] In addition, the groove depth H31 (dimension symbols omitted in the figure) of the radial groove portion 431 is in the range of 0.80≦H31 / Hs≦1.00 relative to the height Hs of the side block 4 (see FIG. 2), and preferably in the range of 0.85≦H31 / Hs≦0.95.

[0080] 6, the radial groove portion 431 is inclined in the same direction as the second shoulder lug groove 312 with respect to the tire radial direction. The inclination angle θ31 of the radial groove portion 431 with respect to the tire radial direction is in the range of 5[deg]≦θ31≦35[deg], preferably in the range of 15[deg]≦θ31≦25[deg], with the bending direction of the L-shaped groove 43 toward the tire radial inside being positive. As a result, as shown in FIG. 5, in the extension range of the radial groove portion 431, the circumferential length of the long block portion 41 increases toward the tire radial inside, and conversely, the circumferential length of the short block portion 42 decreases toward the tire radial inside.

[0081] The inclination angle θ31 of the radial groove portion 431 is measured as an angle between an imaginary line connecting both ends of the radial groove portion 431 and the tire radial direction.

[0082] 4, the front and rear edge portions in the tire circumferential direction of the side block 4 are inclined in the opposite direction in the tire radial direction to the radial groove portion 431 (see FIG. 6) of the L-shaped groove 43. As a result, the long block portion 41 is tapered in width from the mold split position M toward the tire radial inside, and the short block portion 42 is tapered in width from the mold split position M toward the tire radial inside. The inclination angle (dimension symbols omitted in the figure) of the front and rear edge portions in the tire circumferential direction with respect to the tire radial direction is in the range of -35 degrees to -5 degrees, and preferably in the range of -25 degrees to -15 degrees, with the bending direction of the L-shaped groove 43 toward the tire radial inside being taken as the positive angle.

[0083] In Fig. 4, the spacing between adjacent side blocks 4, 4 is in the range of 90% to 110% of the groove width (dimension symbol omitted in the figure; see dimension symbol Wg in Fig. 6) at the radially inner end of the first shoulder lug groove 311, and preferably in the range of 95% to 105%. This improves snow removal from the first shoulder lug groove 311 to between the adjacent side blocks 4, 4.

[0084] 5, the circumferential groove portion 432 extends in the tire circumferential direction and opens to one edge portion in the tire circumferential direction of the side block 4. This improves snow removal performance from the L-shaped groove 43. In the configuration in FIG. 5, the circumferential groove portion 432 extends in the tire circumferential direction and defines a radially inner edge portion of the short block portion 42.

[0085] 6, the groove width W32 of the circumferential groove portion 432 is in the range of 0.45≦W32 / W31≦0.75 with respect to the groove width W31 of the radial groove portion 431, and preferably in the range of 0.50≦W32 / W31≦0.70. The groove width W32 of the circumferential groove portion 432 is in the range of 1.0 [mm]≦W32≦5.0 [mm], and preferably in the range of 2.0 [mm]≦W32≦4.0 [mm]. This promotes snow removal from the radial groove portion 431 to the circumferential groove portion 432.

[0086] Moreover, the groove depth H32 (dimension symbols in the figure are omitted) of the circumferential groove portion 432 is in the range of 0.80≦H32 / Hs≦1.00, and preferably in the range of 0.85≦H32 / Hs≦0.95, relative to the height Hs (see FIG. 2) of the side block 4. The above-mentioned lower limit ensures the groove depth H32 of the circumferential groove portion 432 and ensures the snow traction effect of the circumferential groove portion 432, and the above-mentioned upper limit prevents deterioration of snow removal performance from the L-shaped groove 43 caused by the circumferential groove portion 432 being too deep.

[0087] As shown in FIG. 6, the circumferential groove portion 432 extends from the bending point of the L-shaped groove 43 in one direction in the tire circumferential direction, specifically, toward the short block portion 42, and opens to the circumferential edge portion of the side block 4. At this time, the inclination angle θ32 of the circumferential groove portion 432 with respect to the tire radial direction is in the range of 45 [deg] ≦ θ32 ≦ 135 [deg], preferably in the range of 65 [deg] ≦ θ32 ≦ 115 [deg], and more preferably in the range of 75 [deg] ≦ θ32 ≦ 95 [deg], with the bending direction of the L-shaped groove 43 toward the inside in the tire radial direction being positive. In the configuration of FIG. 6, 90 [deg] < θ32, and the circumferential groove portion 432 is inclined toward the outside in the tire radial direction toward the circumferential edge portion of the side block 4. In this configuration, the circumferential groove portion 432 has an edge component in the tire radial direction, thereby improving the snow traction of the tire.

[0088] The inclination angle θ32 of the circumferential groove portion 432 is measured as the angle between an imaginary line connecting both ends of the circumferential groove portion 432 and the tire radial direction.

[0089] In addition, in Figure 6, the bending angle of the L-shaped groove 43 (dimension symbols omitted in the figure), i.e., the angle between the radial groove portion 431 and the circumferential groove portion 432, is in the range of 80 degrees or more and 120 degrees or less, and preferably in the range of 90 degrees or more and 110 degrees or less.

[0090] 5, the side block 4 has only the L-shaped groove 43, but may have thin shallow grooves, sipes, etc. (not shown). There are no particular limitations on the planar shapes of the long block portion 41 and the short block portion 42, and they may satisfy the above conditions.

[0091] In addition, in the configuration of FIG. 6, the radial groove portion 431 and the circumferential groove portion 432 have a straight line shape, but this is not limited thereto, and at least one of the radial groove portion 431 and the circumferential groove portion 432 may have a gentle arc shape (not shown).

[0092] 1, the side blocks 4 are formed only on the outer buttress portions in the vehicle width direction when the tire is mounted on the vehicle. However, the present invention is not limited to this, and the side blocks 4 may be formed on the left and right buttress portions of the tire (not shown).

[0093] [effect] As described above, [1] the tire 1 includes the first and second shoulder lug grooves 311, 312 that open into the tire buttress portion and are alternately arranged in the tire circumferential direction, the first and second shoulder blocks 321, 322 that are partitioned into the first and second shoulder lug grooves 311, 312 and alternately arranged in the tire circumferential direction, and the side block 4 formed in the tire buttress portion (see FIG. 3). The side block 4 also includes a long block portion 41 that is arranged to overlap the first and second shoulder blocks 321, 322 as viewed in the tire radial direction, a short block portion 42 that is arranged to overlap the second shoulder block 322 and the long block portion 41 as viewed in the tire radial direction, and an L-shaped groove 43 that penetrates the side block 4 and partitions the long block portion 41 and the short block portion 42 (see FIG. 4). The L-shaped groove 43 is formed by connecting in an L shape a radial groove portion 431 that extends in the tire radial direction and connects to an edge portion on the outer side in the tire radial direction of the side block 4, and a circumferential groove portion 432 that extends in the tire circumferential direction and opens to one edge portion in the tire circumferential direction of the side block 4 (see FIG. 5). The inclination angle θ32 (see FIG. 6) of the circumferential groove portion 432 with respect to the tire radial direction is in the range of 45°≦θ32≦135°, with the bending direction of the L-shaped groove 43 toward the inside in the tire radial direction being taken as the positive direction.

[0094] In this configuration, (1) the side block 4 includes a long block portion 41 that is arranged to overlap the first and second shoulder blocks 321, 322 when viewed in the tire radial direction, and therefore, compared to a configuration (not shown) that includes only short side blocks, the snow traction performance of the tire is improved. Also, (2) the side block 4 includes an L-shaped groove 43 formed by connecting a radial groove portion 431 and a circumferential groove portion 432 in an L-shape, and therefore, the edge components of the side block 4 in the tire circumferential direction and the tire radial direction are increased, and therefore, the snow traction performance of the tire is improved. Furthermore, (3) the circumferential groove portion 432 opens to one edge portion of the side block 4 in the tire circumferential direction, and therefore, the snow removal performance from the L-shaped groove 43 is improved.

[0095] [2] In the tire 1 described in [1] above, the circumferential length L1 of the long block portion 41 is in the range of 0.60≦L1 / Ls≦1.00 relative to the circumferential length Ls of the side block (see FIG. 5). The lower limit ensures the circumferential length L1 of the long block portion 41, which has the advantage of ensuring the effect of the long block portion 41 in improving snow traction performance.

[0096] [3] In the tire 1 described in [2] above, the circumferential length Ls of the side block 4 is in the range of 0.80≦Ls / Pb≦1.00 relative to the pitch length Pb of the first and second shoulder blocks 321, 322 (see FIG. 4). The lower limit ensures the circumferential length L1 of the long block portion 41, thereby ensuring the effect of the long block portion 41 in improving snow traction performance, while the upper limit has the advantage of suppressing deterioration of the ground contact characteristics of the tire caused by the circumferential length Ls of the side block 4 being too large.

[0097] [4] In the tire 1 described in the above [1] to [3], the radial width W1 of the long block portion 41 is in the range of 0.25≦W1 / L1≦0.45 with respect to the circumferential length L1 of the long block portion 41 (see FIG. 5). This provides an advantage in that the aspect ratio of the long block portion 41 is optimized, ensuring the improvement of snow traction performance by the long block portion 41.

[0098] [5] In the tire 1 described in [1] to [4] above, the circumferential length L2 of the short block portions 42 is in the range of 0.35≦L2 / Ls≦0.55 relative to the circumferential length Ls of the side blocks 4 (see FIG. 5). The lower limit ensures the circumferential length L2 of the short block portions 42, ensuring the effect of the short block portions 42 in improving snow traction performance, while the upper limit has the advantage of suppressing deterioration of the tire's ground contact characteristics caused by the short block portions 42 being excessively large.

[0099] [6] In the tire 1 described in [1] to [5] above, the circumferential length L2' (see FIG. 6) of the edge portion on the inner side in the tire radial direction of the short block portion 42 defined by the circumferential groove portion 432 is in the range of 0.70≦L2' / L2≦0.90 relative to the circumferential length L2 (see FIG. 5) of the short block portion 42. The lower limit ensures the improvement of snow traction performance by the short block portion 42, and the upper limit has the advantage of improving snow removal performance in the L-shaped groove 43.

[0100] [7] In the tire 1 described in [1] to [6] above, the radial width W2 of the short block portion 42 is in the range of 0.20≦W2 / L2≦0.50 relative to the circumferential length L2 of the short block portion 42 (see FIG. 5). This optimizes the aspect ratio of the short block portion 42, which has the advantage of improving the snow traction performance by the short block portion 42 and ensuring the snow removal function of the L-shaped groove 43.

[0101] [8] In the tire 1 described in the above items [1] to [7], the radial width W2 of the short block portion 42 is in the range of 0.30≦W2 / W1≦0.60 relative to the radial width W1 of the long block portion 41 (see FIG. 5). This has the advantage of ensuring a balanced arrangement of the long block portions 41 and the short block portions 42.

[0102] [9] In the tire 1 according to the tire 1 described in [1] to [8] above, the mold split position M is provided in the tire buttress portion (see FIG. 5). The long block portions 41 have an edge shape that tapers from the mold split position M toward the tire radially inward. The short block portions 42 have an edge shape that tapers from the mold split position M toward the tire radially inward. This configuration has the advantage that the tapered shape of the long block portions 41 improves the snow traction effect of the side blocks 4, and the tapered shape of the short block portions 42 improves the snow removal effect in the L-shaped grooves 43.

[0103]

[10] In the tire 1 according to the above items [1] to [9], the groove width W32 of the circumferential groove portion 432 is in the range of 0.45≦W32 / W31≦0.75 relative to the groove width W31 of the radial groove portion 431 (see FIG. 6). This has the advantage of facilitating snow removal from the radial groove portion 431 to the circumferential groove portion 432.

[0104]

[11] In the tire 1 described in [1] to

[10] above, the groove depth H32 (dimension symbols omitted in the figure) of the circumferential groove portion 432 is in the range of 0.80≦H32 / Hs≦1.00 with respect to the height Hs (see FIG. 2) of the side block 4. The above lower limit ensures the groove depth H32 of the circumferential groove portion 432, thereby ensuring the snow traction effect of the circumferential groove portion 432, while the above upper limit has the advantage of suppressing deterioration of snow removal performance from the L-shaped groove 43 caused by the circumferential groove portion 432 being too deep.

[0105]

[12] In the tire 1 according to the above items [1] to

[11] , the height Hs of the side blocks 4 is in the range of 0.5 mm≦Hs≦3.0 mm. This has the advantage that the height Hs of the side blocks 4 is optimized.

[0106] Applies to In this embodiment, as described above, a pneumatic tire has been described as an example of a tire. However, the present invention is not limited to this, and the configuration described in this embodiment can be arbitrarily applied to other tires within the scope of what is obvious to a person skilled in the art. Examples of other tires include airless tires and solid tires. EXAMPLES

[0107] 7 and 8 are tables showing the results of performance tests of the tire according to the embodiment of the present invention.

[0108] In this performance test, several types of test tires were evaluated for (1) snow traction performance and (2) snow removal performance. In addition, a test tire with a tire size of LT225 / 65R17 102H was mounted on a rim with a rim size of 17x6.5J, and an internal pressure of 230 kPa and the specified load of JATMA were applied to the test tire. In addition, the test tires were mounted on all wheels of a crossover SUV, which was the test vehicle.

[0109] (1) In the evaluation of snow traction performance, the test vehicle is driven on a specified snowy road surface, and the test driver performs a sensory evaluation of the traction performance. This evaluation is performed using an index evaluation with the comparative example as the standard (100), and the higher the value, the more preferable it is.

[0110] (2) In the evaluation of snow removal performance, the test vehicle is driven on a specified snowy road surface, and then the grooves of the side blocks are observed to evaluate the degree of snow clogging. This evaluation is performed using an index evaluation with the comparative example as the standard (100), and the higher the value, the better.

[0111] The test tires of the comparative example and the example have the configurations shown in Figs. 1 to 4 and include a side block 4 on the buttress portion on the outer side in the vehicle width direction. A unit consisting of one side block 4 and a pair of shoulder blocks 321, 322 is arranged around the entire circumference of the tire. The side block 4 includes an L-shaped groove 43 that divides the long block portion 41 and the short block portion 42. The tire cross-sectional height SH is 142.2 mm, the pitch length Pb of the shoulder blocks 321, 322 and the pitch length Ps of the side block 4 are equal and are 59.1 mm on average in the tire circumferential direction, the height Hs of the side block 4 is 1.5 mm, and the groove width W32 of the radial groove portion 431 of the side block 4 is in the range of 4.5 mm to 6.0 mm.

[0112] As the test results show, the test tires of the examples are able to improve the snow traction performance of the tires while ensuring the snow removal performance of the side block grooves. [Explanation of symbols]

[0113] 1 tire; 2 circumferential main groove; 3 land portion; 311, 312 shoulder lug groove; 321, 322 shoulder block; 4 side block; 41 long block portion; 42 short block portion; 43 L-shaped groove; 431 radial groove portion; 432 circumferential groove portion; 11 bead core; 12 bead filler; 13 carcass layer; 14 belt layer; 141, 142 cross belt; 143 belt cover; 15 tread rubber; 16 sidewall rubber; 17 rim cushion rubber

Claims

1. A tire comprising: first and second shoulder lug grooves that open into a tire buttress portion and are alternately arranged in a tire circumferential direction; first and second shoulder blocks that are defined by the first and second shoulder lug grooves and are alternately arranged in a tire circumferential direction; and side blocks formed in the tire buttress portion, The side block includes a long block arranged to overlap the first and second shoulder blocks, respectively, as viewed in the tire radial direction, a short block arranged to overlap the second shoulder block and the long block portion, respectively, as viewed in the tire radial direction, and an L-shaped groove penetrating the side block and partitioning the long block portion and the short block portion, The L-shaped groove is formed by connecting a radial groove portion that extends in the tire radial direction and connects to an edge portion of the side block on the outer side in the tire radial direction, and a circumferential groove portion that extends in the tire circumferential direction and opens to one edge portion of the side block in the tire circumferential direction, in an L-shape, and A tire characterized in that an inclination angle θ32 of the circumferential groove portion with respect to the tire radial direction is in a range of 45°≦θ32≦135°, with the bending direction of the L-shaped groove toward the inside in the tire radial direction being taken as positive.

2. 2. The tire according to claim 1, wherein a circumferential length L1 of the long block portion and a circumferential length Ls of the side block are in a range of 0.60≦L1 / Ls≦1.

00.

3. 3. The tire according to claim 2, wherein a circumferential length Ls of the side block and a pitch length Pb of the first and second shoulder blocks are in a range of 0.80≦Ls / Pb≦1.

00.

4. 2. The tire according to claim 1, wherein a radial width W1 of each of the long block portions and a circumferential length L1 of each of the long block portions are in a range of 0.25≦W1 / L1≦0.

45.

5. 2. The tire according to claim 1, wherein a circumferential length L2 of the short block portion and a circumferential length Ls of the side block are in a range of 0.35≦L2 / Ls≦0.

55.

6. 2. The tire according to claim 1, wherein a circumferential length L2' of an edge portion on an inner side in the tire radial direction of the short block portion defined by the circumferential groove portion is in a range of 0.70≦L2' / L2≦0.90 relative to the circumferential length L2 of the short block portion.

7. 2. The tire according to claim 1, wherein a radial width W2 of each of the short block portions and a circumferential length L2 of each of the short block portions are in a range of 0.20≦W2 / L2≦0.

50.

8. 2. The tire according to claim 1, wherein a radial width W2 of each of the short block portions and a radial width W1 of each of the long block portions are in a range of 0.30≦W2 / W1≦0.

60.

9. The mold split position is provided in the tire buttress area, The long block portion has an edge shape that is tapered and widened from a mold split position toward an inner side in a tire radial direction, and 2. The tire according to claim 1, wherein the short block portion has an edge shape tapered in width from a parting position of the mold toward an inner side in a tire radial direction.

10. The tire according to claim 1 , wherein a groove width W32 of the circumferential groove portion and a groove width W31 of the radial groove portion are in a range of 0.45≦W32 / W31≦0.

75.

11. The tire according to claim 1, wherein a groove depth H32 of the circumferential groove portion and a height Hs of the side block are in a range of 0.80≦H32 / Hs≦1.

00.

12. 2. The tire according to claim 1, wherein the height Hs of the side block is in the range of 0.5 mm≦Hs≦3.0 mm.

Images