Tire

Abstract

To provide a tire improved in on-snow performance while maintaining steering stability on a dry road surface.SOLUTION: The tire comprises a tread part 2. The tread part 2 includes at least one land part 4. The land part 4 includes a first vertical edge 10a, a second vertical edge 10b and a tread surface 10s. The land part 4 is provided with a plurality of first sipes 16, a plurality of second sipes 17 and a plurality of third sipes 18. The plurality of first sipes 16 respectively incline in a first direction with respect to a tire axial direction. The plurality of second sipes 17 respectively incline in a second direction that is the opposite direction of the first direction with respect to the tire axial direction. The third sipe 18 includes a first inclining part 18A extending from the first vertical edge 10a and inclining in the first direction and a second inclining part 18B extending from the second vertical edge 10b and inclining in the second direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] The following Patent Document 1 proposes a tire with a plurality of lateral grooves in a land portion. The lateral groove includes a first portion extending from a first longitudinal edge of the land portion, a second portion extending from a second longitudinal edge of the land portion, and a connecting portion connecting these. The connecting portion includes a raised bottom portion in at least a part thereof. The tire of Patent Document 1 improves the driving stability on dry roads and the performance on snow by the lateral groove including the above-mentioned connecting portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-189106 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, with the improvement of vehicle performance, further improvement in snow performance is also required for tires. To meet such demands, for example, providing sipes on the land portion of the tire is considered. However, sipes tend to reduce the rigidity of the land portion, which in turn impairs the driving stability on dry road surfaces.

[0005] The present invention has been devised in view of the above circumstances, and has as its main object to provide a tire which has improved performance on snow while maintaining steering stability on dry roads. [Means for solving the problem]

[0006] The present invention is a tire having a tread portion, the tread portion including at least one land portion, the land portion including a first longitudinal edge extending in a tire circumferential direction, a second longitudinal edge extending in a tire circumferential direction, and a tread surface between the first longitudinal edge and the second longitudinal edge, the land portion including a plurality of first sipes extending from the first longitudinal edge and having a closed end within the tread surface, a plurality of second sipes extending from the second longitudinal edge and having a closed end within the tread surface, and a plurality of second sipes extending from the first longitudinal edge to the second longitudinal edge. a plurality of third sipes are provided, each of the plurality of first sipes being inclined in a first direction with respect to the tire axial direction, each of the plurality of second sipes being inclined in a second direction opposite to the first direction with respect to the tire axial direction, and each of the plurality of third sipes including a first inclined portion extending from the first longitudinal edge and inclined in the first direction with respect to the tire axial direction, and a second inclined portion extending from the second longitudinal edge and inclined in the second direction with respect to the tire axial direction. Effect of the Invention

[0007] By adopting the above-mentioned configuration, the tire of the present invention can improve performance on snow while maintaining steering stability on dry road surfaces. [Brief description of the drawings]

[0008] [Figure 1] 1 is a development view of a tread portion showing one embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of the crown land portion of FIG. [Diagram 3] 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] FIG. 3 is a cross-sectional view taken along line BB in FIG. [Diagram 5] 2 is an enlarged view of the first middle land portion and the second middle land portion of FIG. 1. [Figure 6] 6 is a cross-sectional view taken along line CC in FIG. 5. [Figure 7] FIG. 6 is a cross-sectional view taken along line DD in FIG. 5. [Figure 8]2 is an enlarged view of a first shoulder land portion, a first middle land portion, and a crown land portion in FIG. 1. [Figure 9] 2 is an enlarged view of a second shoulder land portion, a second middle land portion, and a crown land portion in FIG. 1. [Figure 10] FIG. 2 is a development view of a tread portion of a tire of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings are described to include the features of the present invention, but may include exaggerated expressions and expressions different from the dimensional ratios of the actual structure in order to facilitate understanding of the present invention. In addition, the same reference numerals are used to refer to the same or common elements throughout the embodiments, and duplicated explanations will be omitted.

[0010] Fig. 1 is a development view of a tread portion 2 of a tire 1 showing one embodiment of the present invention. The tire 1 of this embodiment is a pneumatic tire for passenger cars, and is suitably used as an all-season tire (also called an all-weather tire) that can be driven on snowy road surfaces in addition to dry and wet road surfaces. However, the present invention is not limited to such an embodiment, and may be applied to a pneumatic tire for heavy loads and a non-pneumatic tire that is not filled with pressurized air inside the tire.

[0011] As shown in FIG. 1, the tread portion 2 of the present invention includes at least one land portion 4. The tread portion 2 of this embodiment includes a first tread edge T1, a second tread edge T2, a plurality of circumferential grooves 3 extending continuously in the tire circumferential direction between the first tread edge T1 and the second tread edge T2, and a plurality of land portions 4 divided by these circumferential grooves 3. More specifically, the tire 1 of this embodiment includes a tread portion 2 that is composed of four circumferential grooves 3 and five land portions 4. In FIG. 1, dots are applied to the openings of the grooves and sipes. Meanwhile, in other figures described later, the dots are omitted.

[0012] For example, the mounting orientation of the tread portion 2 of this embodiment on a vehicle is specified. As a result, the first tread edge T1 is intended to be located on the outer side of the vehicle when mounted on the vehicle. The second tread edge T2 is intended to be located on the inner side of the vehicle when mounted on the vehicle. The mounting orientation on the vehicle is indicated, for example, by letters or symbols on the sidewall portion (not shown). However, the tire 1 of the present invention is not limited to this embodiment, and the mounting orientation on the vehicle may not be specified.

[0013] The first tread edge T1 and the second tread edge T2 each correspond to the edge of the contact patch when the tire 1 in a normal state is loaded with 70% of the normal load and the tread portion 2 is brought into contact with a flat surface at a camber angle of 0°.

[0014] "Normal condition" means, in the case of a pneumatic tire for which various standards are established, that the tire is mounted on a normal rim, inflated to the normal internal pressure, and unloaded. In the case of a tire for which various standards are not established or a non-pneumatic tire, the normal condition means a standard use condition according to the intended use of the tire, in which the tire is not mounted on a vehicle and is unloaded. In this specification, unless otherwise specified, the dimensions of each part of the tire are values ​​measured in the normal condition.

[0015] A "genuine rim" is a rim that is defined for each tire by the standard system that includes the standard on which the tire is based. For example, in the case of JATMA, it is called a "standard rim," in the case of TRA, it is called a "Design Rim," and in the case of ETRTO, it is called a "Measuring Rim."

[0016] "Normal internal pressure" is the air pressure set for each tire by each standard in the standard system on which the tire is based. In the case of JATMA, it is the "maximum air pressure." In the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." In the case of ETRTO, it is the "INFLATION PRESSURE."

[0017] In the case of pneumatic tires for which various standards are established, the "normal load" is the load that each standard specifies for each tire in the standard system that includes the standard on which the tire is based, and is the "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "LOAD CAPACITY" for ETRTO. In addition, in the case of tires for which various standards are not established, the "normal load" refers to the maximum load that can be applied when using the tire in accordance with the above standards.

[0018] The circumferential grooves 3 include, for example, a first shoulder circumferential groove 5 and a second shoulder circumferential groove 6, as well as a first crown circumferential groove 7 and a second crown circumferential groove 8. The first shoulder circumferential groove 5 is provided closest to the first tread edge T1 among the multiple circumferential grooves 3. The second shoulder circumferential groove 6 is provided closest to the second tread edge T2 among the multiple circumferential grooves 3. The first crown circumferential groove 7 is provided between the first shoulder circumferential groove 5 and the tire equator C. The second crown circumferential groove 8 is provided between the second shoulder circumferential groove 6 and the tire equator C.

[0019] The axial distance L1 from the tire equator C to the groove centerline of the first shoulder circumferential groove 5 or the second shoulder circumferential groove 6 is preferably, for example, 20% to 35% of the tread width TW. The axial distance L2 from the tire equator C to the groove centerline of the first crown circumferential groove 7 or the second crown circumferential groove 8 is preferably, for example, 5% to 15% of the tread width TW. The tread width TW is the axial distance from the first tread edge T1 to the second tread edge T2 in the normal state.

[0020] In this specification, when the numerical range of various parameters is described, the numerical range means the numerical range of the average value of the parameter, unless otherwise specified. In addition, the above-mentioned "average value" is, for example, a value obtained by dividing the measurement target of the parameter into a plurality of micro-areas of a suitable size, measuring the parameter for each micro-area, and dividing the sum of the parameter for each micro-area by the number of divided micro-areas.

[0021] The groove width W1 of each circumferential groove 3 is desirably at least 3 mm. The groove width W1 of each circumferential groove 3 is desirably, for example, 3.0% to 7.0% of the tread width TW. The depth of each circumferential groove 3 is, for example, 5 to 10 mm in the case of a pneumatic tire for a passenger car.

[0022] In this embodiment, the first crown circumferential groove 7, the second crown circumferential groove 8, and the second shoulder circumferential groove 6 each have groove edges on both sides that extend linearly parallel to the tire circumferential direction. On the other hand, the first shoulder circumferential groove 5 has a groove edge on the first tread end T1 side that extends linearly parallel to the tire circumferential direction, and a groove edge on the second tread end T2 side that extends in a zigzag shape. Such zigzag groove edges are useful for improving traction on snow.

[0023] The multiple land portions 4 in this embodiment include a crown land portion 10, a first middle land portion 11, a second middle land portion 12, a first shoulder land portion 13, and a second shoulder land portion 14. The crown land portion 10 in this embodiment is divided between the first crown circumferential groove 7 and the second crown circumferential groove 8. As a result, the crown land portion 10 is provided on the tire equator C. The first middle land portion 11 is divided between the first shoulder circumferential groove 5 and the first crown circumferential groove 7. The second middle land portion 12 is divided between the second shoulder circumferential groove 6 and the second crown circumferential groove 8. The first shoulder land portion 13 is divided on the axially outer side of the first shoulder circumferential groove 5 and includes the first tread edge T1. The second shoulder land portion 14 is divided on the axially outer side of the second shoulder circumferential groove 6 and includes the second tread edge T2.

[0024] Fig. 2 shows an enlarged view of a crown land portion 10 as an example of the land portion 4. As shown in Fig. 2, the crown land portion 10 includes a first longitudinal edge 10a extending in the tire circumferential direction on the first tread end T1 side, a second longitudinal edge 10b extending in the tire circumferential direction on the second tread end T2 side, and a tread surface 10s between the first longitudinal edge 10a and the second longitudinal edge 10b. In addition, the crown land portion 10 is provided with a plurality of first sipes 16, a plurality of second sipes 17, and a plurality of third sipes 18.

[0025] In this specification, "sipe" means a slit having a small width, and in its main body, the width between two inner walls (hereinafter referred to as "sipe walls") is 1.5 mm or less. The main body means a portion where two sipe walls extend substantially parallel to each other in the tire radial direction. "Substantially parallel" means an aspect in which the angle between the two sipe walls is 10° or less. As described later, the sipe may be provided with a chamfered portion. The sipe may also be provided with a so-called flask bottom, the width of which is expanded at the bottom.

[0026] The sipes, with the above-mentioned configuration, can maintain the rigidity of the portion where the sipes are arranged by contacting two sipe walls in the main body when ground pressure acts on the sipes. In this specification, the two groove walls of each groove do not come into contact with each other even when ground pressure acts on the sipes, and the grooves can maintain a substantial drainage path. From this viewpoint, the groove width of each groove is, for example, 2.0 mm or more.

[0027] Each of the first sipes 16 extends from the first longitudinal edge 10a and has a closed end within the tread surface 10s. Each of the second sipes 17 extends from the second longitudinal edge 10b and has a closed end within the tread surface 10s. Each of the third sipes 18 extends from the first longitudinal edge 10a to the second longitudinal edge 10b.

[0028] Each of the first sipes 16 is inclined in a first direction (upward to the right in this embodiment) with respect to the tire axial direction. Each of the second sipes 17 is inclined in a second direction (downward to the right in this embodiment) opposite to the first direction with respect to the tire axial direction. Each of the third sipes 18 includes a first inclined portion 18A and a second inclined portion 18B. The first inclined portion 18A extends from the first longitudinal edge 10a and is inclined in the first direction with respect to the tire axial direction. The second inclined portion 18B extends from the second longitudinal edge 10b and is inclined in the second direction with respect to the tire axial direction. By adopting the above-mentioned configuration, the tire of the present invention can improve the performance on snow while maintaining the steering stability on dry road surfaces (hereinafter, sometimes simply referred to as "steering stability"). The reason is as follows.

[0029] One of the land portions 4 of the tire 1 of the present invention (the crown land portion 10 in this embodiment) is provided with the above-mentioned multiple first sipes 16, multiple second sipes 17, and multiple third sipes 18. These sipes provide frictional forces in multiple directions when driving on snow, and are useful for improving performance on snow. Meanwhile, the first sipes 16 and the second sipes 17 each have a closed end within the land portion, and therefore help maintain the rigidity of the land portion and maintain steering stability on dry road surfaces.

[0030] In the present invention, the first sipe 16 and the first inclined portion 18A of the third sipe 18 extend from the first longitudinal edge 10a at an incline in the same direction. The second sipe 17 and the second inclined portion 18B of the third sipe 18 extend from the second longitudinal edge 10b at an incline in the same direction. This makes it difficult for areas with locally reduced rigidity of the land portion to occur between the first sipe 16 and the third sipe 18 and between the second sipe 17 and the third sipe 18, and thus makes it possible to more reliably maintain steering stability. Due to this mechanism, the tire 1 of the present invention can improve performance on snow while maintaining steering stability on dry road surfaces.

[0031] A more detailed configuration of this embodiment will be described below. Each configuration described below shows a specific aspect of this embodiment. Therefore, it goes without saying that the present invention can achieve the above-mentioned effects even if it does not have the configuration described below. In addition, even if any one of the configurations described below is applied alone to the tire of the present invention having the above-mentioned characteristics, an improvement in performance according to each configuration can be expected. Furthermore, when some of the configurations described below are applied in combination, a composite improvement in performance according to each configuration can be expected.

[0032] In this embodiment, one each of the first sipe 16 and the second sipe 17 is arranged between two third sipes 18 adjacent in the tire circumferential direction. As a result, the sipe pairs consisting of the first sipe 16 and the second sipe 17 and the third sipes 18 are arranged alternately in the tire circumferential direction. Such an arrangement of the sipes makes the rigidity distribution of the crown land portion 10 uniform, and can reliably maintain the driving stability on dry road surfaces. In addition, the above-mentioned arrangement of the sipes reduces the impact sound when the crown land portion 10 touches the ground, improving the noise performance, and also improves the wear resistance of the crown land portion 10.

[0033] The first sipe 16 extends linearly, for example, inclined in the first direction. In another embodiment, the first sipe 16 may be smoothly curved. The axial length L3 of the first sipe 16 is preferably 30% or more, more preferably 40% or more, and preferably 60% or less, more preferably 50% or less of the maximum axial width W2 of the tread surface 10s of the crown land portion 10. Such a first sipe 16 is useful for improving the driving stability and the performance on snow in a well-balanced manner. The length L3 corresponds to the axial length of the center line that divides the width of the sipe in half. The same applies to the description of the length of the sipe below.

[0034] The angle θ1 of the first sipe 16 with respect to the tire axial direction is preferably 40° or more, more preferably 50° or more, and preferably 70° or less, more preferably 60° or less. This improves the traction performance and cornering performance in a well-balanced manner when driving on snow. When the first sipe 16 is curved, the angle θ1 is the average angle of the first sipe 16 with respect to the tire axial direction. The average angle corresponds to the value obtained by dividing the first sipe 16 into a plurality of minute sipe pieces and dividing the sum of the angles of each minute sipe piece in the tire axial direction by the number of minute sipe pieces. Hereinafter, the same applies to the angles of other sipes and lateral grooves unless otherwise specified.

[0035] FIG. 3 shows a cross-sectional view of line AA in FIG. 2. As shown in FIG. 2 and FIG. 3, at least a part of the first sipe 16 is provided with a chamfered portion 16c. As shown in FIG. 3, the chamfered portion 16c means a region where the ridge formed by the tread surface 10s of the land portion and the sipe wall 16w is removed. For this reason, the chamfered portion 16c includes an inclined surface 19 extending from the tread surface 10s at an angle to the tire normal in a cross section perpendicular to the longitudinal direction of the sipe. The sipe with the chamfered portion 16c can prevent the tread surface 10s from lifting off the road surface around the opening, which helps to uniform the ground pressure and prevent uneven wear. From the viewpoint of exerting this effect, the width W4 of the inclined surface 19 of the chamfered portion 16c is at least 50% or more of the width W3 of the main body of the sipe.

[0036] In a preferred embodiment, the width W4 of the inclined surface 19 is preferably 0.5 mm or more, more preferably 1.0 mm or more, and is preferably 2.0 mm or less, more preferably 1.5 mm or less. The depth d1 of the chamfered portion 16c is, for example, 0.5 to 2.0 mm.

[0037] As shown in Figs. 2 and 3, in this embodiment, the chamfered portion 16c is provided on both sides of the first sipe 16 in the width direction. However, the chamfered portion 16c may be provided on one side of the first sipe 16 in the width direction. As shown in Fig. 2, in this embodiment, the chamfered portion 16c is provided over the entire range of the first sipe 16 in the longitudinal direction. This makes the ground pressure uniform around the first sipe 16, and can reliably improve the driving stability. In addition, such chamfered portion 16c can reduce the hitting sound when the first sipe 16 touches the ground, and can also be expected to improve noise performance.

[0038] In a more desirable embodiment, the width of the chamfered portion 16c is constant over 80% or more of the longitudinal direction of the first sipe 16. This can suppress uneven wear around the first sipe 16 and can also improve wear resistance.

[0039] The second sipes 17 extend linearly, for example, inclined in the second direction. In another embodiment, the second sipes 17 may be smoothly curved. The tire axial length L4 of the second sipes 17 is preferably 30% or more, more preferably 40% or more, and preferably 60% or less, more preferably 50% or less of the maximum tire axial width W2 of the tread surface 10s of the crown land portion 10. In addition, when comparing the so-called periphery length along the length direction of the sipes, the length of the second sipes 17 is preferably shorter than the length of the first sipes 16, and more preferably 60% to 75% of the length of the first sipes 16. Such second sipes 17 are useful for improving the steering stability and the performance on snow in a well-balanced manner.

[0040] The angle θ2 of the second sipes 17 relative to the tire axial direction is smaller than the angle θ1 of the first sipes 16 relative to the tire axial direction. Specifically, the angle θ2 of the second sipes 17 relative to the tire axial direction is preferably 10° or more, more preferably 20° or more, and is preferably 40° or less, more preferably 30° or less. Such second sipes 17 cooperate with the above-mentioned first sipes 16 to help improve traction performance and cornering performance in a well-balanced manner when traveling on snow.

[0041] In this embodiment, a chamfered portion 17c is provided on at least a portion of the second sipe 17. The chamfered portion 17c of the second sipe 17 can have the same characteristics as the chamfered portion 16c (shown in FIG. 3) of the first sipe 16. In a preferred embodiment, the chamfered portion 17c is provided over the entire length of the second sipe 17. In a more preferred embodiment, the width of the chamfered portion 17c of the second sipe 17 is constant over 80% or more of the length of the second sipe 17. This improves not only the driving stability but also the noise performance and the wear resistance.

[0042] The distance L5 in the tire circumferential direction from the closed end of the first sipe 16 in the tread surface 10s to the closed end of the second sipe 17 in the tread surface 10s is 30% or less of one pitch length P1 in the tire circumferential direction of the multiple first sipes 16, and preferably 10% to 15%. This allows the first sipes 16 and the second sipes 17 to work together to improve on-snow performance while maintaining steering stability. The one pitch length P1 corresponds to the distance in the tire circumferential direction between the ends of two first sipes 16 adjacent in the tire circumferential direction on the first longitudinal edge 10a side.

[0043] The third sipe 18 is, for example, composed of only the first inclined portion 18A and the second inclined portion 18B. As a result, the third sipe 18 is bent in a direction that convexly extends toward one side in the tire circumferential direction. The intersection of the first inclined portion 18A and the second inclined portion 18B is disposed, for example, in a central region when the tread surface 10s is divided into three equal parts in the tire axial direction. As a result, uneven wear of the crown land portion 10 can be suppressed while the above-mentioned effects can be achieved. However, the third sipe 18 is not limited to this embodiment.

[0044] The first inclined portion 18A of the third sipe 18 extends linearly, for example, inclined in the first direction. In another embodiment, the first inclined portion 18A may be smoothly curved. The angle θ3 of the first inclined portion 18A with respect to the tire axial direction is preferably 40° or more, more preferably 50° or more, and is preferably 70° or less, more preferably 60° or less. This improves the traction performance and cornering performance in a well-balanced manner when traveling on snow.

[0045] The second inclined portion 18B of the third sipe 18 extends linearly, for example, inclined in the second direction. In another embodiment, the second inclined portion 18B may be smoothly curved. The angle θ4 of the second inclined portion 18B with respect to the tire axial direction is preferably 10° or more, more preferably 20° or more, and is preferably 40° or less, more preferably 30° or less. This improves the traction performance and cornering performance when traveling on snow in a well-balanced manner.

[0046] An angle θ3 of the first inclined portion 18A with respect to the tire axial direction is larger than an angle θ4 of the second inclined portion 18B with respect to the tire axial direction. This distributes the frequency bands of the impact sounds when the first inclined portion 18A and the second inclined portion 18B touch the ground, improving noise performance.

[0047] The angle θ5 between the first inclined portion 18A and the second inclined portion 18B is, for example, 90 to 120°. This improves the traction performance and turning performance when traveling on snow. When the first inclined portion 18A or the second inclined portion 18b is curved, the angle θ5 corresponds to the angle between a virtual line connecting both ends of the first inclined portion 18A and a virtual line connecting both ends of the second inclined portion 18B.

[0048] FIG. 4 shows a cross-sectional view of line BB in FIG. 2. As shown in FIG. 4, the third sipe 18 does not have a chamfered portion. That is, the third sipe 18 has a ridge formed by connecting the tread surface 10s of the land portion and the sipe wall 18w. Also, as shown in FIG. 2, the third sipe 18 does not have a chamfered portion in any part, and is configured as a non-chamfered area as a whole. Such a third sipe 18 can provide a large frictional force by its edge when traveling on an icy road.

[0049] FIG. 5 shows an enlarged view of the first middle land portion 11 and the second middle land portion 12. In FIG. 5, the crown land portion 10 provided between these land portions is omitted. As shown in FIG. 5, the first middle land portion 11 includes a first longitudinal edge 11a on the first tread end T1 side (left side in FIG. 5, and the same applies below), a second longitudinal edge 11b on the second tread end T2 side (right side in FIG. 5, and the same applies below), and a tread surface 11s between the first longitudinal edge 11a and the second longitudinal edge 11b. Similarly, the second middle land portion 12 includes a first longitudinal edge 12a on the first tread end T1 side, a second longitudinal edge 12b on the second tread end T2 side, and a tread surface 12s between the first longitudinal edge 12a and the second longitudinal edge 12b.

[0050] The first middle land portion 11 is provided with a plurality of first middle lateral grooves 21 extending from the first longitudinal edge 11a to the second longitudinal edge 11b. Each of the first middle lateral grooves 21 is inclined in a first direction with respect to the tire axial direction from the first longitudinal edge 11a to the second longitudinal edge 11b of the first middle land portion 11.

[0051] The second middle land portion 12 is provided with a plurality of second middle lateral grooves 22 extending from the first longitudinal edge 12a to the second longitudinal edge 12b. Each of the second middle lateral grooves 22 includes a first inclined portion 22A and a second inclined portion 22B. The first inclined portion 22A extends from the first longitudinal edge 12a of the second middle land portion 12 and is inclined with respect to the tire axial direction. The first inclined portion 22A of this embodiment is inclined in the second direction with respect to the tire axial direction. The second inclined portion 22B extends from the second longitudinal edge 12b of the second middle land portion 12 and is inclined in the opposite direction to the first inclined portion 22A with respect to the tire axial direction. The second inclined portion 22B of this embodiment is inclined in the first direction with respect to the tire axial direction.

[0052] Such first middle lateral grooves 21 and second middle lateral grooves 22 can exhibit high drainage performance on wet road surfaces, while providing snow column shear force in multiple directions when driving on snow, thereby improving wet performance and on-snow performance.

[0053] However, if the first middle lateral grooves 21 and the second middle lateral grooves 22 are located at the same circumferential position of the tire, these lateral grooves may locally reduce the circumferential rigidity of the tread portion 2, which may ultimately impair steering stability on dry road surfaces.

[0054] In contrast, in the present embodiment, in a plan view of the tread portion 2, the overlapping area between the imaginary extension region 23 (dotted in FIG. 5) of each of the second middle lateral grooves 22 extending parallel to the tire axial direction toward the first tread edge T1 (left side in FIG. 5) and each of the opening faces of the first middle lateral grooves 21 is 50% or less of the area of ​​the opening face of the first middle lateral groove 21. This suppresses the above-mentioned problems and maintains steering stability on dry roads.

[0055] In order to reliably improve wet and snow performance, each of the second middle lateral grooves 22 is arranged to overlap in the tire circumferential direction with each of the first middle lateral grooves 21. From the viewpoint of improving wet and snow performance and steering stability on dry roads in a well-balanced manner, the overlapping area is preferably 10% to 30% of the area of ​​the opening surface.

[0056] The first middle lateral grooves 21 extend with a constant groove width. The angle θ6 of the first middle lateral grooves 21 with respect to the tire axial direction is, for example, 15 to 50°, and preferably 20 to 40°. The angle θ6 increases toward the second longitudinal edge 11b. As a result, the first middle lateral grooves 21 are curved. Such first middle lateral grooves 21 can improve traction performance and cornering performance on snow in a well-balanced manner.

[0057] FIG. 6 shows a cross-sectional view of line CC in FIG. 5. FIG. 7 shows a cross-sectional view of line DD in FIG. 5. As shown in FIG. 5 to FIG. 7, the first middle lateral groove 21 of this embodiment is provided with a chamfered portion 21c. As shown in FIG. 6 and FIG. 7, the chamfered portion 21c means a region where the ridge angle formed by the tread surface 11s of the land portion and the groove wall 21w is removed. Therefore, the chamfered portion 21c includes an inclined surface 24 that extends from the tread surface 11s at an angle with respect to the tire normal in a cross section perpendicular to the longitudinal direction of the lateral groove. A lateral groove in which the chamfered portion 21c is arranged can prevent the tread surface 11s from lifting up from the road surface around its opening, which is useful for equalizing the ground pressure and preventing uneven wear.

[0058] In order to ensure this effect, the width W5 of the inclined surface 24 of the chamfered portion 21c is, for example, 1.0 to 2.0 mm, as shown in Fig. 7. As a preferred embodiment, the chamfered portion 21c is provided on each of the groove edges on both sides of the first middle lateral groove 21. As shown in Fig. 5, the chamfered portion 21c is provided over the entire longitudinal range of the first middle lateral groove 21. The width of the chamfered portion 21c is constant over 80% or more of the longitudinal length of the first middle lateral groove 21.

[0059] As shown in Figs. 5 to 7, the first middle lateral groove 21 includes a first portion 26 (shown in Fig. 6) in which a sipe 29 is provided at the groove bottom 28, and a second portion 27 (shown in Fig. 7) in which a sipe is not provided at the groove bottom 28. As shown in Fig. 6, the first portion 26 has a smaller depth from the tread 11s to the outer surface 28s of the groove bottom 28 than the second portion 27, and the sipe 29 is provided at this groove bottom 28. The sipe 29 is provided at a central portion when the outer surface 28s of the groove bottom 28 is divided into three equal parts in the width direction. The depth d3 from the tread 11s to the bottom of the sipe 29 is 130% to 170% of the depth d2 from the tread 11s to the outer surface 28s of the groove bottom 28. Such a first portion 26 is useful for improving the driving stability and the snow performance and the wet performance in a well-balanced manner.

[0060] 7, the second portion 27 has a depth d4 from the tread 11s to the outer surface 28s of the groove bottom 28 of 5.0 to 7.0 mm. The depth d4 of the second portion 27 is 80% to 120% of the depth d3 of the first portion 26. Such a second portion 27 helps to improve driving stability and wet performance in a well-balanced manner.

[0061] 5, the first portion 26 occupies 20% to 50% of the first middle lateral groove 21 in the longitudinal direction, and the remaining portion constitutes the second portion 27. Such a first middle lateral groove 21 can reliably exhibit the above-mentioned effects.

[0062] In the present embodiment, the first middle land portion 11 is provided with a first middle lateral groove 21 in which the first portion 26 is disposed closer to the first tread edge T1 than the second portion 27, and a first middle lateral groove 21 in which the second portion 27 is disposed closer to the first tread edge T1 than the first portion 26. In a more preferable embodiment, these two types of first middle lateral grooves 21, in which the arrangement of the first portions 26 is different, are provided alternately in the tire circumferential direction. This improves the wear resistance of the first middle land portion 11.

[0063] The first middle land portion 11 of this embodiment is provided with a plurality of interrupted middle sipes 30. The interrupted middle sipes 30 extend from the first longitudinal edge 11a or the second longitudinal edge 11b, and have closed ends within the tread surface 11s. The interrupted middle sipes 30 of this embodiment include a first interrupted middle sipe 31 and a second interrupted middle sipe 32. The first interrupted middle sipe 31 extends from the first longitudinal edge 11a. The second interrupted middle sipe 32 extends from the second longitudinal edge 11b. The first interrupted middle sipe 31 and the second interrupted middle sipe 32 are useful for improving wet performance and performance on snow, and for improving wear resistance.

[0064] In this embodiment, only one interrupted middle sipe 30 is provided between two first middle lateral grooves 21 adjacent in the tire circumferential direction. In a preferred embodiment, the first interrupted middle sipes 31 and the second interrupted middle sipes 32 are provided alternately in the tire circumferential direction. This further improves the wear resistance.

[0065] The interrupted middle sipes 30 extend linearly, for example, inclined in a first direction with respect to the tire axial direction. The angle θ7 of the first interrupted middle sipes 31 with respect to the tire axial direction is, for example, 15 to 50°, and preferably 15 to 25°. The angle θ8 of the second interrupted middle sipes 32 with respect to the tire axial direction is larger than the angle θ7 of the first interrupted middle sipes 31. Specifically, the angle θ8 of the second interrupted middle sipes 32 is, for example, 15 to 50°, and preferably 30 to 40°. Such interrupted middle sipes 30 improve traction performance and cornering performance on wet roads and snowy roads in a well-balanced manner.

[0066] The axial length L6 of the interrupted middle sipe 30 is, for example, 35% to 65% of the maximum width W6 of the tread surface 11s of the first middle land portion 11, and preferably 40% to 60%. This makes it possible to achieve the above-mentioned effects while maintaining the wear resistance of the first middle land portion 11.

[0067] The interrupted middle sipe 30 is preferably provided with a chamfered portion 30c. The configuration of the chamfered portion 16c of the first sipe 16 shown in FIG. 3 can be applied to this chamfered portion 30c. As a preferred embodiment, the width of the chamfered portion 30c of the interrupted middle sipe 30 in the present embodiment in a direction perpendicular to the longitudinal direction of the sipe becomes smaller toward the closed end within the tread surface 11s. This makes it possible to suppress uneven wear of the first middle land portion 11 while obtaining the edge effect of the interrupted middle sipe 30.

[0068] The second middle lateral groove 22 is composed of only a first inclined portion 22A and a second inclined portion 22B. The first inclined portion 22A and the second inclined portion 22B are connected in a central region when the tread surface 12s of the second middle land portion 12 is divided into thirds in the tire axial direction. As a result, the axial length L7 of the first inclined portion 22A and the axial length L8 of the second inclined portion 22B are each 40% to 60% of the maximum width W7 of the tread surface 12s of the second middle land portion 12. As a result, uneven wear of the second middle land portion 12 is suppressed and the on-snow performance is improved.

[0069] The angle θ9 of the first inclined portion 22A with respect to the tire axial direction is, for example, 5 to 25°. The first inclined portion 22A may be curved in a direction in which the angle θ9 increases toward the second tread edge T2. The angle θ10 of the second inclined portion 22B with respect to the tire axial direction is, for example, 5 to 25°. The second inclined portion 22B may be curved in a direction in which the angle θ10 increases toward the first tread edge T1. This improves the drainage of the second middle lateral grooves 22.

[0070] The angle θ11 between the first inclined portion 22A and the second inclined portion 22B is, for example, an obtuse angle, and is preferably 105 to 135°. This provides the above-mentioned effects while suppressing uneven wear of the second middle land portion 12. If the first inclined portion 22A and the second inclined portion 22B are not straight lines, the angle θ11 corresponds to the angle between a virtual line connecting both ends of the groove center line of the first inclined portion 22A and a virtual line connecting both ends of the groove center line of the second inclined portion 22B.

[0071] The second middle lateral grooves 22 have sipes at the bottom of one of the first inclined portion 22A and the second inclined portion 22B, and no sipes at the bottom of the other of the first inclined portion 22A and the second inclined portion 22B. The configuration of the first portion 26 (shown in FIG. 6) of the first middle lateral grooves 21 can be applied to the region of the second middle lateral grooves 22 where the sipes are provided at the bottom. The configuration of the second portion 27 (shown in FIG. 7) of the first middle lateral grooves 21 can be applied to the region of the second middle lateral grooves 22 where the sipes are not provided at the bottom. Such second middle lateral grooves 22 can reliably improve wet performance and on-snow performance while maintaining steering stability.

[0072] The second middle land portion 12 is provided with a second middle lateral groove 22 having a sipe at the groove bottom of the first inclined portion 22A, and a second middle lateral groove 22 having a sipe at the groove bottom of the second inclined portion 22B. In a more preferable embodiment, these two types of second middle lateral grooves 22 having different sipe arrangements are alternately provided in the tire circumferential direction. This improves the wear resistance of the second middle land portion 12.

[0073] The second middle land portion 12 is provided with a plurality of transverse middle sipes 35. The transverse middle sipes 35 extend from the first longitudinal edge 12a to the second longitudinal edge 12b of the second middle land portion 12. In this embodiment, one or two transverse middle sipes 35 are provided between two second middle lateral grooves 22 adjacent in the tire circumferential direction.

[0074] The transverse middle sipe 35 includes a first sipe piece 36 and a second sipe piece 37 that are inclined in different directions relative to the tire axial direction. The first sipe piece 36 is inclined in the second direction relative to the tire axial direction from the first longitudinal edge 12a. As a result, the first sipe piece 36 extends along the first inclined portion 22A of the second middle lateral groove 22, and the angle difference therebetween is 5° or less. Specifically, the angle θ12 of the first sipe piece 36 relative to the tire axial direction is 5° to 25°.

[0075] The second sipe piece 37 is inclined in the first direction from the second longitudinal edge 12b with respect to the tire axial direction. As a result, the second sipe piece 37 extends along the second inclined portion 22B of the second middle lateral groove 22, and the angle difference therebetween is 5° or less. Specifically, the angle θ13 of the second sipe piece 37 with respect to the tire axial direction is 5° to 25°.

[0076] The transverse middle sipes 35 include the above-mentioned first sipe pieces 36 and second sipe pieces 37, and thus can provide frictional forces in multiple directions on wet road surfaces.

[0077] The axial length L9 of the first sipe piece 36 is, for example, 40% to 60% of the axial maximum width W7 of the tread surface 12s of the second middle land portion 12. In a preferred embodiment, the length L9 of the first sipe piece 36 is substantially the same as the axial length L7 of the first inclined portion 22A of the second middle lateral groove 22. Similarly, the axial length L10 of the second sipe 17 is also 40% to 60% of the maximum width W7 of the tread surface 12s of the second middle land portion 12, and is preferably the same as the axial length L8 of the second inclined portion 22B of the second middle lateral groove 22. This makes it possible to suppress uneven wear of the second middle land portion 12 while achieving the above-mentioned effects.

[0078] The transverse middle sipe 35 is preferably provided with a chamfered portion 35c. The chamfered portion 35c may have the configuration of the chamfered portion 16c of the first sipe 16 shown in FIG. 3. In a preferred embodiment, the chamfered portion 35c of the transverse middle sipe 35 of this embodiment has a width in a direction perpendicular to the longitudinal direction of the sipe that is smaller toward the connecting portion 38 between the first sipe piece 36 and the second sipe piece 37. This makes it possible to suppress uneven wear of the second middle land portion 12 while obtaining the edge effect of the transverse middle sipe 35.

[0079] Fig. 8 shows an enlarged view of the first shoulder land portion 13, the first middle land portion 11, and the crown land portion 10. As shown in Fig. 8, the first shoulder land portion 13 is provided with a plurality of first shoulder lateral grooves 41 and a plurality of first shoulder sipes 42. In this embodiment, the first shoulder lateral grooves 41 and the first shoulder sipes 42 are provided alternately in the tire circumferential direction.

[0080] The first shoulder lateral groove 41 extends from the first shoulder circumferential groove 5 to at least the first tread edge T1. The first shoulder lateral groove 41 includes, for example, a portion inclined in the first direction with respect to the tire axial direction. The maximum angle θ14 of the first shoulder lateral groove 41 with respect to the tire axial direction is, for example, 10 to 20°. Such a first shoulder lateral groove 41 helps to improve wet performance and on-snow performance.

[0081] A chamfered portion 41c is provided in the first shoulder lateral groove 41. The chamfered portion 41c of the first shoulder lateral groove 41 may have the same structure as the chamfered portion 21c of the first middle lateral groove 21 (shown in FIGS. 6 and 7).

[0082] The first shoulder sipes 42 extend from the first shoulder circumferential groove 5 to the first tread edge T1. The first shoulder sipes 42 may be terminated just before the first tread edge T1. The first shoulder sipes 42 include a portion inclined in the first direction with respect to the tire axial direction. The maximum angle θ15 of the first shoulder sipes 42 with respect to the tire axial direction is 10 to 20°. In a preferred embodiment, the first shoulder sipes 42 extend along the first shoulder lateral grooves 41, and the angle difference therebetween is 5° or less. Such first shoulder sipes 42 cooperate with the first shoulder lateral grooves 41 to provide high traction on wet roads and snowy roads.

[0083] The first shoulder sipes 42 are provided with chamfered portions 42c. The chamfered portions 42c of the first shoulder sipes 42 may have the same configuration as the chamfered portions 16c (shown in FIG. 3) of the first sipes 16. In a preferred embodiment, the chamfered portions 42c are provided over the entire longitudinal range of the first shoulder sipes 42, and the width of the chamfered portions 42c is constant over 80% or more of the longitudinal length of the first shoulder sipes 42. Such first shoulder sipes 42 can improve wet performance while suppressing uneven wear of the first shoulder land portion 13.

[0084] In this embodiment, in a plan view of the tread portion 2, the arrangement relationship between adjacent lateral grooves and sipes with a circumferential groove interposed therebetween is optimized, thereby achieving further improvement in various performances.

[0085] For example, in a plan view of the tread, a first imaginary groove 51 (dotted in FIG. 8 ) extended toward the crown land portion 10 while maintaining the groove width and angle of the first middle lateral groove 21 overlaps with an end of the first sipe 16 on the first crown circumferential groove 7 side. Similarly, a second imaginary groove 52 (dotted in FIG. 8 ) extended toward the first middle land portion 11 while maintaining the groove width and angle of the first shoulder lateral groove 41 overlaps with an end of the first middle lateral groove 21 on the first shoulder circumferential groove 5 side. As a result, when traveling on snow, the first sipe 16, the first middle lateral groove 21, and the first shoulder lateral groove 41 cooperate to provide a reaction force, thereby improving traction on snow.

[0086] Fig. 9 shows an enlarged view of the second shoulder land portion 14, the second middle land portion 12, and the crown land portion 10. As shown in Fig. 9, the second shoulder land portion 14 is provided with a plurality of second shoulder lateral grooves 43 and a plurality of second shoulder sipes 44. In this embodiment, one or two second shoulder sipes 44 are provided between two second shoulder lateral grooves 43 adjacent to each other in the tire circumferential direction.

[0087] The second shoulder lateral groove 43 extends from the second shoulder circumferential groove 6 to at least the second tread edge T2. The second shoulder lateral groove 43 includes, for example, a portion inclined in the first direction with respect to the tire axial direction. The maximum angle θ16 of the second shoulder lateral groove 43 with respect to the tire axial direction is, for example, 10 to 20°. Such second shoulder lateral groove 43 helps to improve wet performance and on-snow performance.

[0088] A chamfered portion 43c is provided in the second shoulder lateral groove 43. The chamfered portion 43c of the second shoulder lateral groove 43 may have the same configuration as the chamfered portion 21c of the first middle lateral groove 21 (shown in Figs. 6 and 7).

[0089] The second shoulder sipes 44 extend from the second shoulder circumferential groove 6 to the second tread edge T2. The second shoulder sipes 44 may be terminated just before the second tread edge T2. The second shoulder sipes 44 include a portion inclined in the first direction with respect to the tire axial direction. The maximum angle θ17 of the second shoulder sipes 44 with respect to the tire axial direction is 10 to 20°. In a preferred embodiment, the second shoulder sipes 44 extend along the second shoulder lateral grooves 43, and the angle difference therebetween is 5° or less. Such second shoulder sipes 44 can improve wet performance and on-snow performance while suppressing uneven wear of the second shoulder land portion 14.

[0090] The second shoulder sipes 44 are provided with chamfered portions 44c. The chamfered portions 44c of the second shoulder sipes 44 may have the same configuration as the chamfered portions 16c (shown in FIG. 3) of the first sipes 16. As a preferred embodiment, the chamfered portions 44c are provided over the entire longitudinal range of the second shoulder sipes 44, and the width of the chamfered portions 44c becomes smaller toward the second tread edge T2.

[0091] In the plan view of the tread, a third imaginary groove 53 (dotted in FIG. 9 ) that extends toward the crown land portion 10 while maintaining the groove width and angle of the second middle lateral groove 22 overlaps with an end of the second sipe 17 on the second crown circumferential groove 8 side. Similarly, a fourth imaginary groove 54 (dotted in FIG. 9 ) that extends toward the second middle land portion 12 while maintaining the groove width and angle of the second shoulder lateral groove 43 overlaps with an end of the second middle lateral groove 22 on the second shoulder circumferential groove 6 side. As a result, when traveling on snow, the second sipe 17, the second middle lateral groove 22, and the second shoulder lateral groove 43 cooperate to provide a reaction force, thereby improving traction on snow.

[0092] Although the tire according to one embodiment of the present invention has been described in detail above, the present invention is not limited to the above specific embodiment and can be modified and carried out in various aspects. EXAMPLES

[0093] As an example, a pneumatic tire of size 225 / 45ZR18 having the basic pattern of Fig. 1 was prototyped. As a comparative example, a tire having a tread portion shown in Fig. 10 was prototyped. The comparative example tire has a crown land portion a provided with a plurality of sipes b inclined in one direction with respect to the tire axial direction. The comparative example tire has substantially the same configuration as the example tire, except for the above-mentioned points.

[0094] The comparative example and the example were tested for steering stability on dry roads and performance on snow. The common specifications and test methods for each test tire are as follows. Rim: 18×8.0J Tire pressure: front wheel 220kPa, rear wheel 240kPa Test vehicle: 2000cc, rear-wheel drive Tire mounting position: All wheels

[0095] <Steering stability on dry roads> The driving stability of the test vehicle when it was driven on a dry road surface was evaluated by the driver. A higher score indicates better driving stability.

[0096] <Snow performance> The driving performance of the test vehicle when it was driven on snowy roads was evaluated by the driver. The higher the score, the better the performance on snow. The test results are shown in Table 1.

[0097] [Table 1]

[0098] As shown in Table 1, the comparative example has a steering stability of 98 points on dry roads, whereas the examples 1 to 9 have steering stability of 97 to 100 points, and it can be seen that the steering stability is maintained. On the other hand, the comparative example has a snow performance of 90 points, whereas the examples 1 to 9 have snow performance of 100 to 102 points, and it can be seen that the snow performance is improved by 10 points or more compared to the comparative example. In other words, as a result of the above test, it was confirmed that the tires of the examples have improved snow performance while maintaining steering stability on dry roads.

[0099] [Note] The present invention includes the following aspects.

[0100] [Invention 1] A tire having a tread portion, The tread portion includes at least one land portion, The land portion includes a first longitudinal edge extending in a tire circumferential direction, a second longitudinal edge extending in a tire circumferential direction, and a tread surface between the first longitudinal edge and the second longitudinal edge, The land portion is provided with a plurality of first sipes extending from the first longitudinal edge and having a closed end within the tread surface, a plurality of second sipes extending from the second longitudinal edge and having a closed end within the tread surface, and a plurality of third sipes extending from the first longitudinal edge to the second longitudinal edge, Each of the plurality of first sipes is inclined in a first direction with respect to the tire axial direction, Each of the plurality of second sipes is inclined in a second direction opposite to the first direction with respect to the tire axial direction, Each of the plurality of third sipes includes a first inclined portion extending from the first longitudinal edge and inclined in the first direction with respect to the tire axial direction, and a second inclined portion extending from the second longitudinal edge and inclined in the second direction with respect to the tire axial direction. tire. [Invention 2] The tire according to the present invention 1, wherein the land portion is a crown land portion provided on the tire equator. [Invention 3] The tire according to the first or second aspect of the present invention, wherein one of the first sipes and one of the second sipes are disposed between two of the third sipes adjacent to each other in the tire circumferential direction. [Invention 4] The tire according to any one of claims 1 to 3, wherein a chamfered portion is provided on at least a part of the first sipe. [Invention 5] The tire according to any one of claims 1 to 4, wherein a chamfered portion is provided over an entire area of ​​the first sipe in the longitudinal direction. [Invention 6] The tire according to the present invention 5, wherein the width of the chamfered portion is constant over 80% or more of the first sipe in the longitudinal direction. [Invention 7] The tire according to any one of claims 1 to 6, wherein a chamfered portion is provided on at least a part of the second sipe. [Invention 8] The tire according to any one of claims 1 to 7, wherein a chamfered portion is provided over an entire area of ​​the second sipe in the longitudinal direction. [The present invention 9] The tire according to invention 8, wherein the width of the chamfered portion is constant over 80% or more of the second sipe in the longitudinal direction. [The present invention 10] The tire according to any one of claims 1 to 9, wherein the third sipe is not provided with a chamfered portion. [The present invention 11] The tire according to any one of claims 1 to 10, wherein an angle of the first inclined portion with respect to the tire axial direction is larger than an angle of the second inclined portion with respect to the tire axial direction. [The present invention 12] 12. The tire according to any one of claims 1 to 11, wherein the angle of the first inclined portion with respect to the tire axial direction is 50 to 60°. [The present invention 13] 13. The tire according to any one of claims 1 to 12, wherein the second inclined portion has an angle of 20 to 30° with respect to the tire axial direction. [Invention 14] The tire according to any one of claims 1 to 13, wherein the length of the first sipe in the tire axial direction is 40% to 50% of the maximum width of the tread surface in the tire axial direction. [The present invention 15] The tire according to any one of claims 1 to 14, wherein the length of the second sipe in the tire axial direction is 40% to 50% of the maximum width of the tread surface in the tire axial direction. [The present invention 16] The tire according to any one of claims 1 to 15, wherein the distance in the tire circumferential direction from the end of the first sipe to the end of the second sipe is 10% to 15% of one pitch length in the tire circumferential direction of the plurality of first sipes. [Explanation of symbols]

[0101] 2 Tread section 4 Land 10a First vertical edge 10b 2nd vertical edge 10s tread 16 First sipe 17 Second sipe 18 3rd sipe 18A 1st slope section 18B 2nd slope part

Claims

1. A tire having a tread portion, The tread portion includes at least one land portion, The land portion includes a first longitudinal edge extending in a tire circumferential direction, a second longitudinal edge extending in a tire circumferential direction, and a tread surface between the first longitudinal edge and the second longitudinal edge, The land portion is provided with a plurality of first sipes extending from the first longitudinal edge and having a closed end within the tread surface, a plurality of second sipes extending from the second longitudinal edge and having a closed end within the tread surface, and a plurality of third sipes extending from the first longitudinal edge to the second longitudinal edge, Each of the plurality of first sipes is inclined in a first direction with respect to the tire axial direction, Each of the plurality of second sipes is inclined in a second direction opposite to the first direction with respect to the tire axial direction, Each of the plurality of third sipes includes a first inclined portion extending from the first longitudinal edge and inclined in the first direction with respect to the tire axial direction, and a second inclined portion extending from the second longitudinal edge and inclined in the second direction with respect to the tire axial direction. tire.

2. The tire according to claim 1 , wherein the land portion is a crown land portion provided on the tire equator.

3. The tire according to claim 1 , wherein one of the first sipes and one of the second sipes are disposed between two of the third sipes that are adjacent to each other in the tire circumferential direction.

4. The tire according to claim 1 or 2, wherein a chamfer is provided on at least a portion of the first sipe.

5. The tire according to claim 1 or 2, wherein a chamfered portion is provided over an entire area of ​​the first sipe in the longitudinal direction.

6. The tire according to claim 5 , wherein the width of the chamfered portion is constant over 80% or more of the first sipe in the longitudinal direction.

7. The tire according to claim 1 or 2, wherein a chamfer is provided on at least a portion of the second sipe.

8. The tire according to claim 1 or 2, wherein a chamfered portion is provided over an entire area of ​​the second sipe in the longitudinal direction.

9. The tire according to claim 8 , wherein the width of the chamfered portion is constant over 80% or more of the second sipe in the longitudinal direction.

10. The tire according to claim 1 or 2, wherein the third sipe is not provided with a chamfered portion.

11. The tire according to claim 1 , wherein an angle of the first inclined portion with respect to the tire axial direction is larger than an angle of the second inclined portion with respect to the tire axial direction.

12. The tire according to claim 1 or 2, wherein an angle of the first inclined portion with respect to the tire axial direction is 50 to 60 degrees.

13. The tire according to claim 1 or 2, wherein an angle of the second inclined portion with respect to the tire axial direction is 20 to 30 degrees.

14. 3. The tire according to claim 1, wherein the axial length of the first sipe is 40% to 50% of the maximum axial width of the tread surface.

15. 3. The tire according to claim 1, wherein the axial length of the second sipe is 40% to 50% of the maximum axial width of the tread surface.

16. 3. The tire according to claim 1, wherein a distance in the tire circumferential direction from the end of the first sipe to the end of the second sipe is 10% to 15% of one pitch length in the tire circumferential direction of the plurality of first sipes.

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