tire

Abstract

Provided is a tire having improved braking / driving performance and turning performance on ice.　The tire has a tread part 2. The tread part 2 includes a land portion 4. A plurality of closed sipes 8 are arranged in a tire axial direction in the land portion 4. Each of the closed sipes 8 includes: a first end 8a and a second end 8b; a first sipe piece 11 extending from the first end 8a side in the tire axial direction; a second sipe piece 12 extending from the second end 8b side in the tire axial direction; and a third sipe piece 13 inclined with respect to the tire axial direction between the first sipe piece 11 and the second sipe piece 12. The closed sipes 8 arranged in the tire axial direction overlap each other in the tire axial direction.

Description

[Technical Field]

[0001] The present disclosure relates to tires. [Background technology]

[0002] Various pneumatic tires have been proposed in the past with linear or zigzag sipes in the land portions of the tread (see, for example, Patent Document 1 below). The edges of the sipes exert road-gripping power (edge ​​effect), thereby improving performance on ice.

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-025812 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, high traction performance and braking performance (hereinafter, these may be collectively referred to as "driving and braking performance") are required on ice. Therefore, in many cases, a plurality of sipes extending in the tire axial direction are arranged in the tire circumferential direction on the land portion of the tread.

[0005] Meanwhile, in recent years, with the advancement of vehicle performance, there has been a demand for improved cornering performance on ice. Therefore, in order to increase axial friction, sipes that include components extending in the tire circumferential direction are sometimes arranged on tires. However, when multiple such sipes are arranged in the tire circumferential direction, the number of sipes that can be arranged per unit length in the tire circumferential direction on the land portion tends to be reduced. This has led to a risk of impairing braking and driving performance on ice.

[0006] The present disclosure has been devised in view of the above problems, and has as its main object to provide a tire with improved braking / driving performance and cornering performance on ice. [Means for solving the problem]

[0007] The present disclosure relates to a tire including a tread portion, wherein the tread portion includes a land portion, and a plurality of closed sipes having a width of 1.5 mm or less are arranged in the tire axial direction in the land portion, and each of the closed sipes includes a first end and a second end, a first sipe piece extending in the tire axial direction on the first end side, a second sipe piece extending in the tire axial direction on the second end side, and a third sipe piece inclined with respect to the tire axial direction between the first sipe piece and the second sipe piece, and the closed sipes arranged in the tire axial direction overlap each other in the tire axial direction and the tire circumferential direction. [Effects of the Invention]

[0008] In the present disclosure, by adopting the above configuration, it is possible to exhibit excellent braking / driving performance and cornering performance on ice. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a tread portion of a tire according to one embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged plan view of the land portion of FIG. [Figure 3] FIG. 3 is an enlarged view of the closed sipe of FIG. 2. [Figure 4] FIG. 2 is a transparent perspective view showing an example of the inside of a closed sipe. [Figure 5] FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. [Figure 6] FIG. 10 is a transparent perspective view showing another example of the inside of a closed sipe. [Figure 7] 7A and 7B are cross-sectional views taken along lines BB and CC in FIG. 6. [Figure 8] 7A and 7B are cross-sectional views taken along lines DD and EE in FIG. 6. [Figure 9] FIG. 10 is a transparent perspective view showing another example of the inside of a closed sipe. [Figure 10] FIG. [Figure 11] FIG. 10 is a transparent perspective view showing another example of the inside of a closed sipe. [Figure 12] FIG. 12 is an enlarged plan view of the land portion provided with the closed sipes shown in FIG. 11 when worn. [Figure 13] FIG. 10 is a transparent perspective view showing yet another example of the inside of a closed sipe. [Figure 14] FIG. 14 is an enlarged plan view of the land portion provided with the closed sipes shown in FIG. 13 when worn. [Figure 15] FIG. 10 is an enlarged plan view of a land portion according to another embodiment of the present disclosure. [Figure 16] FIG. 10 is an enlarged plan view of a land portion according to another embodiment of the present disclosure. [Figure 17] FIG. 2 is an enlarged plan view of a land portion of a tire of a comparative example. [Explanation of symbols]

[0010] 2 Tread section 4 Land 8 Closed sipes 8a 1st end 8b 2nd end 11 First sipe piece 12 Second sipe piece 13 Third sipe piece DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 shows a cross-sectional view of a tread portion 2 of a tire 1 according to the present embodiment. Fig. 1 is a meridian cross-sectional view including the tire rotation axis of the tire 1 in a normal state. The tire 1 according to the present embodiment is suitably used, for example, as a pneumatic tire for a passenger vehicle. However, the tire 1 according to the present disclosure is not limited to this embodiment, and may be used, for example, for a heavy load vehicle.

[0012] "Normal condition" refers to a state in which, in the case of a pneumatic tire for which various standards are established, the tire is mounted on a normal rim, inflated to the normal internal pressure, and no load is applied. In the case of a tire for which various standards are not established or a non-pneumatic tire, the normal condition refers to a standard use state according to the intended use of the tire, and a state in which no load is applied. Unless otherwise specified, the dimensions of each part of the tire in this specification are values ​​measured in the normal condition. Note that each configuration described in this specification allows for normal errors that are inherent in rubber molded products.

[0013] 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."

[0014] "Normal internal pressure" is the air pressure specified for each tire by each standard in the standard system, including the standard on which the tire is based. For JATMA, it is the "maximum air pressure," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "INFLATION PRESSURE."

[0015] As shown in FIG. 1, a tread portion 2 is provided with, for example, a plurality of main grooves 3 extending continuously in the tire circumferential direction and a plurality of land portions 4 separated from the main grooves 3.

[0016] Fig. 2 shows an enlarged plan view of the land portion 4. As shown in Fig. 2, the land portion 4 of this embodiment is configured, for example, as a block row including a plurality of blocks 6 in the tire circumferential direction. The blocks 6 are separated between a plurality of lateral grooves 5 that cross the land portion 4 in the tire axial direction. The land portion 4 of the present disclosure is not limited to this form, and may be, for example, a rib that extends continuously in the tire circumferential direction.

[0017] In some of the drawings in this specification, arrows indicate a first side A1 in the tire circumferential direction, an opposite second side A2 in the tire circumferential direction, a first side B1 in the tire axial direction, and an opposite second side B2 in the tire axial direction. Unless otherwise specified, in drawings showing a plan view of a land portion 4, the upper direction is the first side A1 in the tire circumferential direction, the lower direction is the second side A2 in the tire circumferential direction, the left direction is the first side B1 in the tire axial direction, and the right direction is the second side B2 in the tire axial direction.

[0018] In the land portion 4, a plurality of closed sipes 8 are arranged in the tire axial direction. In this embodiment, a plurality of sipe groups 7, each of which has a plurality of arranged closed sipes 8, are provided in one block 6. One sipe group 7 is made up of, for example, 3 to 7 closed sipes 8.

[0019] In this specification, the term "sipe" refers to a very small cut, with the width between two opposing sipe walls being 1.5 mm or less. In a preferred embodiment, the width of the closed sipe 8 of this embodiment is 1.0 mm or less. In addition, in this specification, the term "closed sipe" refers to a sipe whose both ends are interrupted within the land portion 4. The sipe group 7 provided in the block 6 of this embodiment is composed only of closed sipes 8. In other words, no sipes are connected to the edge of the block 6. However, this is not limited to this embodiment, and the sipes arranged near the edge of the block 6 may be unclosed sipes whose one end opens at the edge.

[0020] FIG. 3 shows an enlarged view of the closed sipe 8 of FIG. 2. As shown in FIG. 3, the closed sipes 8 each include a first end 8a and a second end 8b, and a first sipe piece 11, a second sipe piece 12, and a third sipe piece 13. The first end 8a is an end of the closed sipe 8 on a first side B1 in the tire axial direction. The second end 8b is an end of the closed sipe 8 on a second side B2 in the tire axial direction. The first sipe piece 11 extends in the tire axial direction on the first end 8a side of the third sipe piece 13. The second sipe piece 12 extends in the tire axial direction on the second end 8b side of the third sipe piece 13. The third sipe piece 13 is inclined with respect to the tire axial direction between the first sipe piece 11 and the second sipe piece 12. With this arrangement, in the closed sipe 8 of this embodiment, the first sipe piece 11 is arranged on the first side A1 in the tire circumferential direction and on the first side B1 in the tire axial direction of the second sipe piece 12. Also, in this embodiment, the first sipe piece 11 is continuous with the first side A1 in the tire circumferential direction of the third sipe piece 13. The second sipe piece 12 is continuous with the second side A2 in the tire circumferential direction of the third sipe piece 13.

[0021] The closed sipes 8 arranged in the tire axial direction overlap each other in the tire axial direction and the tire circumferential direction. Note that "closed sipes 8 overlap each other in the tire axial direction" means that an imaginary area obtained by extending one closed sipe 8 parallel to the tire circumferential direction overlaps with an adjacent closed sipe 8. Also, "closed sipes 8 overlap each other in the tire circumferential direction" means that an imaginary area obtained by extending one closed sipe 8 parallel to the tire axial direction overlaps with an adjacent closed sipe 8.

[0022] By adopting the above-described configuration, the present disclosure can exhibit excellent braking / driving performance and cornering performance on ice. The following mechanism is presumed to be the reason for this.

[0023] The sipe group 7 of the present disclosure includes a plurality of closed sipes 8 aligned in the tire axial direction. The closed sipes 8 are difficult to open during braking and driving, making it difficult for snow and ice to become clogged inside, and the edge effect can be stably exerted over a long period of time. This improves snow clogging resistance when driving on snow. The closed sipes 8 also increase the pattern rigidity of the land portion 4, improving steering stability on dry roads.

[0024] In addition, because the third sipe pieces 13 are inclined with respect to the tire axial direction, they exert frictional force in the tire axial direction on ice, thereby improving cornering performance on ice. Furthermore, because the second sipe pieces 12 of the closed sipes 8 overlap with the first sipe pieces 11 of the axially adjacent closed sipes 8 in the tire axial direction and the tire circumferential direction, many closed sipes 8 can be arranged in the land portion 4, resulting in excellent braking / driving performance on ice.

[0025] In this embodiment, an imaginary area obtained by extending the second sipe piece 12 of one closed sipe 8 parallel to the tire circumferential direction overlaps with the first sipe piece 11 of the adjacent closed sipe 8. Also, an imaginary area obtained by extending the third sipe piece 13 of one closed sipe 8 parallel to the tire axial direction overlaps with the third sipe piece 13 of the adjacent closed sipe 8. However, the present disclosure is not limited to such an embodiment.

[0026] The configuration of this embodiment will be described in more detail below. As shown in FIG. 2, the sipe group 7 of this embodiment extends along the tire axial direction, but may extend at a certain angle relative to the tire axial direction. Specifically, an imaginary straight line 18 (shown by a two-dot chain line) connecting a first end 8a of a closed sipe 8 provided at the end of the first side B1 in the tire axial direction and a second end 8b of the closed sipe 8 provided at the end of the second side B2 in the tire axial direction is, for example, at an angle of 45° or less, preferably 15° or less, and more preferably 5° or less, relative to the tire axial direction. However, the sipe group 7 is not limited to this configuration and can be changed depending on the shape of the land portion. As will be described later, for example, the imaginary straight line 18 may extend obliquely.

[0027] As a more desirable aspect, in this embodiment, the first ends 8a of each closed sipe 8 are arranged on the same imaginary belt 15 (colored in FIG. 2) that extends parallel to the tire axial direction with a very small width. The width of the imaginary belt 15 is, for example, 3.0 mm or less. As a more desirable aspect, the first ends 8a of each closed sipe 8 are arranged on the same imaginary straight line that extends parallel to the tire axial direction. Similarly, the second ends 8b of each closed sipe 8 are arranged on the same imaginary belt (not shown) that extends parallel to the tire axial direction with a very small width. The width of the imaginary belt is, for example, 3.0 mm or less. As a more desirable aspect, the second ends 8b of each closed sipe 8 are arranged on the same imaginary straight line that extends parallel to the tire axial direction.

[0028] As shown in FIG. 3, the overlap length L2 of two adjacent closed sipes 8 in the tire axial direction is preferably 10% to 40% of the maximum axial length L1 of the closed sipes 8. This maintains the wear resistance of the land portion 4 while providing excellent braking / driving performance. If the overlap length L2 is less than 10% of the length L1, the axial edge component of the land portion 4 will be reduced, which may result in a decrease in braking / driving performance on ice. If the overlap length L2 exceeds 40% of the length L1, the clearance between two adjacent closed sipes 8 will be narrowed, which may result in uneven wear of the land portion. Note that each sipe length is measured from the center line of the sipe in the width direction.

[0029] The distance L3 in the tire circumferential direction between the second end 8b of one closed sipe 8 and the first end 8a of the adjacent closed sipe 8 is, for example, 10% or less, and preferably 5% or less, of the length L6 in the tire circumferential direction of the third sipe piece 13. In this embodiment, the second end 8b is located closer to the first side A1 in the tire circumferential direction than the first end 8a. This prevents a decrease in rigidity of the land portion 4, ensuring wear resistance and steering stability on dry roads.

[0030] In this embodiment, the first end 8a and the second end 8b are located closer to the second side A2 in the tire circumferential direction than the first sipe piece 11 and closer to the first side A1 in the tire circumferential direction than the second sipe piece 12. In other words, the first end 8a and the second end 8b are located within a region (not shown) that extends parallel to the tire axial direction from the third sipe piece 13 toward both sides in the tire axial direction. Furthermore, the closed sipe 8 of this embodiment includes a first outer sipe piece 16 and a second outer sipe piece 17. The first outer sipe piece 16 extends from the first end 8a to the first sipe piece 11. The second outer sipe piece 17 extends from the second end 8b to the second sipe piece 12. Such a closed sipe 8 provides a large frictional force in the tire axial direction by the first outer sipe piece 16 and the second outer sipe piece 17, improving cornering performance on ice.

[0031] The angle between the first sipe piece 11 and the third sipe piece 13 and the angle between the second sipe piece 12 and the third sipe piece 13 are each, for example, 80° or more, and preferably 90° or more. In this embodiment, the above-mentioned two angles are set to 100 to 120°. This suppresses wear at the curved portions of the closed sipes 8, improving uneven wear resistance.

[0032] Similarly, the angle between the first sipe piece 11 and the first outer sipe piece 16 and the angle between the second sipe piece 12 and the second outer sipe piece are each, for example, 80° or more, and preferably 90° or more. In this embodiment, the above-mentioned two angles are 100 to 120°.

[0033] In this embodiment, each sipe piece of the closed sipe 8 extends linearly. However, each sipe piece may extend in a curved manner, for example.

[0034] The axial length L4 of the first sipe piece 11 and the axial length L5 of the second sipe piece 12 are each greater than the axial length of the third sipe piece 13. The length L4 of the first sipe piece 11 and the length L5 of the second sipe piece 12 are each 35% to 45% of the axial length L1 of the closed sipe 8.

[0035] The angle of the first sipe piece 11 relative to the tire axial direction and the angle of the second sipe piece 12 relative to the tire axial direction are, for example, in the range of ±20°, and preferably in the range of ±10°. In this embodiment, the first sipe piece 11 and the second sipe piece 12 each extend parallel to the tire axial direction. Such first sipe piece 11 and second sipe piece 12 help to effectively improve braking / driving performance on ice.

[0036] As shown in Figure 2, in a more desirable embodiment, the first sipe pieces 11 of each closed sipe 8 are arranged on the same imaginary belt (not shown) that extends parallel to the tire axial direction with a very small width. The width of the imaginary belt is, for example, 3.0 mm or less. In a more desirable embodiment, the first sipe pieces 11 of each closed sipe 8 are arranged on the same imaginary straight line that extends parallel to the tire axial direction. This maintains uneven wear resistance and improves braking / driving performance.

[0037] Similarly, the second sipe pieces 12 of each closed sipe 8 are arranged on the same imaginary belt (not shown) that extends parallel to the tire axial direction with a very small width. The width of the imaginary belt is, for example, 3.0 mm or less. In a more desirable embodiment, the second sipe pieces 12 of each closed sipe 8 are arranged on the same imaginary straight line that extends parallel to the tire axial direction.

[0038] 3, the circumferential length L6 of the third sipe piece 13 is smaller than, for example, the axial length L1 of the closed sipe 8. The length L6 of the third sipe piece 13 is also smaller than the axial length L4 of the first sipe piece 11 and the axial length L5 of the second sipe piece 12. Specifically, the length L6 of the third sipe piece 13 is 25% to 40% of the length L1 of the closed sipe 8. Such a third sipe piece 13 improves cornering performance on ice while maintaining uneven wear resistance.

[0039] The third sipe piece 13 is inclined, for example, from the first sipe piece 11 toward the second side B2 in the tire axial direction toward the second side A2 in the tire circumferential direction. The third sipe piece 13 is arranged at a larger angle with respect to the tire axial direction than the first sipe piece 11 and the second sipe piece 12. However, the third sipe piece 13 may, for example, extend parallel to the tire circumferential direction. The angle of the third sipe piece 13 of this embodiment with respect to the tire axial direction is, for example, 45° or more, and preferably 60 to 80°. Such a third sipe piece 13 improves cornering performance on ice while also providing frictional force in the tire circumferential direction.

[0040] 2, the closed sipes 8 of this embodiment are arranged so that the third sipe pieces 13 are parallel to each other. This improves the uneven wear resistance of the land portion 4 and the steering stability on dry roads.

[0041] 3, the tire circumferential length L7 of the first outer sipe piece 16 and the tire circumferential length L8 of the second outer sipe piece 17 are, for example, shorter than the tire circumferential length of the third sipe piece 13. The length L7 of the first outer sipe piece 16 and the length L8 of the second outer sipe piece 17 are preferably 60% or less of the length L6 of the third sipe piece 13, and more preferably 45% to 55%. This ensures a sufficient clearance between two adjacent closed sipes 8. Therefore, uneven wear resistance is maintained, and demoldability during vulcanization molding is also ensured.

[0042] The first outer sipe piece 16 and the second outer sipe piece 17 are each inclined in the opposite direction to the third sipe piece 13 with respect to the tire circumferential direction. The angle of the first outer sipe piece 16 with respect to the tire circumferential direction and the angle of the second outer sipe piece 17 with respect to the tire circumferential direction are each, for example, 45° or less, and desirably 10 to 30°. In a desirable embodiment, the angle of the first outer sipe piece 16 and the angle of the second outer sipe piece 17 are each the same as the angle of the third sipe piece 13 with respect to the tire circumferential direction. However, without being limited to this embodiment, the first outer sipe piece 16 and the second outer sipe piece 17 may, for example, extend parallel to the tire circumferential direction.

[0043] In this embodiment, of two axially adjacent closed sipes 8, the second sipe piece 12 of one closed sipe 8 axially overlaps with the first sipe piece 11 of the other closed sipe 8. The second outer sipe piece 17 of the one closed sipe 8 extends from the second sipe piece 12 toward the first side A1 in the tire circumferential direction. The first outer sipe piece 16 of the other closed sipe 8 extends from the first sipe piece 11 toward the second side A2 in the tire circumferential direction. This more reliably achieves the above-mentioned effects.

[0044] Next, the internal configuration of the closed sipe 8 will be described. Fig. 4 shows a transparent perspective view illustrating an example of the inside of the closed sipe 8, and Fig. 5 shows a cross-sectional view taken along line AA in Fig. 4. In this specification, in the transparent perspective view such as Fig. 4, the edges on the tread surface of the closed sipe 8 are shown by solid lines, and the internal shape of the closed sipe 8 is shown by dashed lines.

[0045] 4 and 5, in this embodiment, the entire closed sipe 8 extends linearly in the tire radial direction in its sipe cross section. In the present disclosure, even if the cross-sectional shape of the sipe is linear as described above, the rigidity of the land portion 4 is maintained by the closed sipe 8, both ends of which are interrupted within the land portion 4, and therefore sufficient steering stability and uneven wear resistance are exhibited. On the other hand, the closed sipe 8 having such a sipe cross section improves demolding during vulcanization molding, and is useful for reducing the reject rate during tire production and reducing the costs of manufacturing and maintaining the vulcanization mold.

[0046] Fig. 6 shows a see-through perspective view illustrating another example of the interior of a closed sipe 8. Fig. 7 shows cross-sectional views taken along lines BB and CC in Fig. 6. As shown in Figs. 6 and 7, in this embodiment, the first sipe piece 11 and the second sipe piece 12 are each configured as bent portions 20 extending in a zigzag pattern in the tire radial direction in the sipe cross section. Such closed sipes 8 increase the rigidity of the land portions 4 in the tire circumferential direction, enabling excellent braking / driving performance on ice.

[0047] The bent portion 20 includes an outer inclined portion 21 that is continuous with the edge of the closed sipe 8 and extends at an angle in one direction relative to the tire radial direction. In the embodiment shown in Fig. 6, the outer inclined portion 21 belonging to the first sipe piece 11 is inclined toward a first side A1 in the tire circumferential direction toward the tire radially inward. The outer inclined portion 21 belonging to the second sipe piece 12 is inclined toward a second side A2 in the tire circumferential direction toward the tire radially inward. This ensures a large volume of the rubber portion surrounded by the first sipe piece 11, the third sipe piece 13, and the first outer sipe piece 16, as well as the volume of the rubber portion surrounded by the second sipe piece 12, the third sipe piece 13, and the second outer sipe piece 17, which in turn makes it possible to prevent chipping of the rubber when the tire is demolded during vulcanization molding.

[0048] Figure 8 shows a cross-sectional view taken along line DD and line EE in Figure 6. As shown in Figures 6 and 8, in this embodiment, the first outer sipe piece 16 and the second outer sipe piece 17 are each configured as bent portions 20 extending in a zigzag pattern in the tire radial direction in their sipe cross sections. Such closed sipes 8 increase the axial rigidity of the land portion 4, enabling excellent cornering performance on ice.

[0049] 6, the outer inclined portion 21 belonging to the first outer sipe piece 16 is inclined radially inward toward a first side B1 in the tire axial direction. The outer inclined portion 21 belonging to the second outer sipe piece 17 is inclined radially inward toward a second side B2 in the tire axial direction. This makes it possible to suppress rubber chipping when demolding during vulcanization molding, using the same mechanism as described above.

[0050] In the present disclosure, the arrangement of the bent portion 20 can be changed in various ways depending on the purpose of the tire. In other embodiments, for example, the first sipe piece 11 and the second sipe piece 12 may have the cross-sectional shape shown in Fig. 7, with the other portions extending parallel to the tire radial direction. Such closed sipes 8 can improve demoldability during vulcanization molding and exhibit excellent braking / driving performance on ice.

[0051] In still another embodiment, for example, the first outer sipe piece 16 and the second outer sipe piece 17 may have the cross-sectional shape shown in Fig. 8, and the other portions may extend parallel to the tire radial direction. Such closed sipes 8 can improve demoldability during vulcanization molding and exhibit excellent cornering performance on ice.

[0052] Fig. 9 shows a see-through perspective view showing the inside of yet another closed sipe 8. As shown in Fig. 9, in this embodiment, each sipe piece of the closed sipe 8 is configured as a bent portion 20 extending in a zigzag pattern in the tire radial direction. Such a closed sipe 8 can further increase the rigidity of the land portion 4 when closed, and can exhibit excellent uneven wear resistance.

[0053] In the embodiment shown in FIG. 9 , the directions of inclination of the outer inclined portions 21 of each sipe piece interfere with each other. For this reason, in this embodiment, the outer inclined portions 21 are preferably configured as follows. That is, in this embodiment, the outer inclined portion 21 belonging to the first sipe piece 11 and the outer inclined portion 21 belonging to the second sipe piece 12 are each inclined toward the first circumferential side A1 in the tire radially inward direction. Furthermore, the outer inclined portion 21 belonging to the first outer sipe piece 16 and the outer inclined portion 21 belonging to the second outer sipe piece 17 are each inclined toward the first axial side B1 in the tire radially inward direction. Furthermore, the outer inclined portion 21 belonging to the third sipe piece 13 is inclined toward the second axial side B2 in the tire radially inward direction. With the above configuration, each sipe piece is configured as a bent portion 20, and the above-mentioned effects can be achieved.

[0054] In the present disclosure, the closed sipe 8 having the planar shape shown in FIGS. 2 and 3 may have any of the cross-sectional shapes shown in FIGS.

[0055] Fig. 10 shows an enlarged cross-sectional view of the bending portion 20. As shown in Fig. 10, the bending portion 20 preferably includes two or more first convex portions 23 that are convex on one side. The bending portion 20 of this embodiment is composed of two first convex portions 23 and one second convex portion 24 that is convex on the other side and is located between the two first convex portions 23.

[0056] The widthwise center line 25 of the bent portion 20 includes a first vertex 25a where the bent portion 20 bends at the first convex portion 23 and a second vertex 25b where the bent portion 20 bends at the second convex portion 24. An imaginary line (not shown) connecting both ends of the center line 25 of the bent portion 20 is preferably parallel to the tire radial direction. The second vertex 25b is preferably located on the imaginary line.

[0057] The center line 25 of the bending portion 20 includes an outer end 25o on the outer side in the tire radial direction and an inner end 25i on the inner side in the tire radial direction. The bending portion 20 also includes two bending elements 30. In this embodiment, the bending element 30 is composed of a first bending element 31 extending from the outer end 25o to the second vertex 25b and a second bending element 32 extending from the second vertex 25b to the inner end 25i. In this embodiment, the radial length L9 of the first bending element 31 (the radial distance from the outer end 25o to the second vertex 25b) and the radial length L10 of the second bending element 32 (the radial distance from the inner end 25i to the second vertex 25b) are the same. This bending portion 20 can uniformly improve traction performance and braking performance on ice.

[0058] The bending width W1 of the bending portion 20 (the distance in the width direction of the sipe from the first vertex 25a to the second vertex 25b) is, for example, 0.1 to 1.0 mm, thereby suppressing molding defects during vulcanization molding while achieving the above-mentioned effects.

[0059] The closed sipes 8 desirably include vertical portions 35 that are continuous with the bent portions 20 on the radially inner side of the tire and extend parallel to the tire radial direction. The length L11 of the vertical portions 35 in the tire radial direction is, for example, 10% to 30% of the maximum depth d1 of the closed sipes 8. This makes it easier for the knife blade of the vulcanization mold that forms the bent portions 20 to pierce the raw rubber of the tire during vulcanization molding, thereby suppressing deformation and damage to the knife blade.

[0060] Fig. 11 is a see-through perspective view showing another example of the interior of the closed sipe 8. As shown in Fig. 11, the closed sipe 8 of this embodiment includes a connecting portion 26 where opposing sipe walls are partially connected to each other and protrude radially outward of the tire.

[0061] Generally, when a sipe comes into contact with the ground and a load is applied in the circumferential direction of the tire, shear deformation is likely to occur, causing one sipe wall to become misaligned with the other sipe wall in the depth direction of the sipe. This deformation can lead to a decrease in the circumferential rigidity of the tread portion of the tire, which in turn can lead to a decrease in braking performance on dry roads and on ice, and can also lead to uneven wear, such as heel-and-toe wear, around the sipes. This uneven wear also tends to exacerbate the deterioration of tire performance due to wear.

[0062] The closed sipes 8 shown in Fig. 11 can suppress the above-mentioned deformation by the connecting portions 26, thereby improving steering stability and braking performance on ice. Furthermore, suppressing the above-mentioned deformation is also highly effective in suppressing uneven wear (heel-and-toe wear). Therefore, by suppressing the uneven wear, the closed sipes 8 having the connecting portions 26 can reduce changes in tire performance due to wear, thereby making it possible to provide a tire that can maintain high safety over a long period of time.

[0063] Furthermore, since the closed sipes 8 described above are difficult to open, snow is less likely to get stuck inside the sipes while driving. This action prevents the side walls of the blocks 6 provided with the closed sipes 8 from bulging out, ensuring the volume of the grooves that separate the blocks 6 and thus preventing a decrease in performance on snow and ice.

[0064] The above-mentioned deformation of the sipes tends to occur first in the portions of the sipes where the axial component is large, and then propagate to the portions of the sipes where the circumferential component is large. Therefore, it is desirable to suppress deformation in the portions of the sipes where the axial component is large. From this perspective, it is desirable that the connecting portion 26 is provided on at least one of the first sipe piece 11 and the second sipe piece 12, for example. As a more desirable aspect, in this embodiment, the connecting portion 26 is provided on both the first sipe piece 11 and the second sipe piece 12. This ensures the above-mentioned effects.

[0065] The height in the tire radial direction of the connecting portion 26 provided on the first sipe piece 11 is, for example, 80% to 120% of the height in the tire radial direction of the connecting portion 26 provided on the second sipe piece 12, and preferably these are the same. This allows the rigidity around the closed sipe 8 to be uniformly increased by the two connecting portions 26, further improving the above-mentioned effect.

[0066] The connecting portion 26 extends in the tire radial direction with a constant width, for example. The width W2 (width along the length direction of the closed sipe 8) of the connecting portion 26 provided on the first sipe piece 11 is preferably 10% to 50% of the length L4 (shown in FIG. 3) of the first sipe piece 11, and more preferably 20% to 30%. The width of the connecting portion 26 provided on the second sipe piece 12 is set to a similar range to the length L5 (shown in FIG. 3) of the second sipe piece 12. This makes it possible to fully exert the above-mentioned effects while maintaining the frictional force provided by the edges of the closed sipe 8. Note that when the width of the connecting portion 26 varies in the tire radial direction, the width is measured at the center position of the connecting portion 26 in the tire radial direction.

[0067] The height h1 of the connecting portion 26 in the tire radial direction is, for example, 10% to 90% of the maximum depth d1 (shown in FIG. 10) of the closed sipe 8. On the other hand, it is desirable to determine the height h1 appropriately depending on the purpose of the tire. This is because, as shown in FIG. 12, when the land portion 4 provided with the closed sipe 8 having the connecting portion 26 wears, the connecting portion 26 becomes exposed and the edge component of the closed sipe 8 is reduced.

[0068] From this perspective, as shown in Fig. 11, in the case of a winter tire that prioritizes performance on snow, the height h1 is preferably 20% to 40% of the maximum depth d1 of the closed sipe 8. On the other hand, in the case of an all-season tire that is intended for year-round use, the height h1 is preferably 50% to 70% of the depth d1. This allows performance according to the purpose of the tire to be obtained.

[0069] Fig. 13 shows a see-through perspective view illustrating yet another example of the interior of a closed sipe 8. In the closed sipe 8 of this embodiment, similar to the embodiment shown in Fig. 11, a connecting portion 26 is provided on the first sipe piece 11 and the second sipe piece 12, and a connecting portion 26 is also provided on the third sipe piece 13. In the embodiment of Fig. 13, by providing a connecting portion 26 on the third sipe piece 13 as well, deformation of the closed sipe 8 in the tire axial direction is further suppressed. Therefore, further improvements in handling stability and cornering performance on ice can be expected.

[0070] Hereinafter, in the embodiment shown in Figure 13, the connecting portion 26 provided on the first sipe piece 11 may be referred to as the first connecting portion 26a, the connecting portion 26 provided on the second sipe piece 12 may be referred to as the second connecting portion 26b, and the connecting portion 26 provided on the third sipe piece 13 may be referred to as the third connecting portion 26c.

[0071] The configuration of the connecting portion 26 shown in Fig. 11 can be applied to the first connecting portion 26a and the second connecting portion 26b shown in Fig. 13, and a description thereof will be omitted here. In a preferred embodiment, the first connecting portion 26a and the second connecting portion 26b have substantially the same configuration. This makes the progression of wear uniform around the first sipe piece 11 and the second sipe piece 12, thereby suppressing uneven wear.

[0072] The height h2 of the third connecting portion 26c is, for example, 10% to 90% of the maximum depth d1 (shown in FIG. 10) of the closed sipe 8. On the other hand, it is desirable to determine the height h2 appropriately depending on the purpose of the tire. This is because, as shown in FIG. 14, when the land portion 4 on which the closed sipe 8 having the connecting portion 26 is provided wears, the first connecting portion 26a, the second connecting portion 26b, and the third connecting portion 26c become exposed, and the edge components of the closed sipe 8 are reduced.

[0073] From this perspective, as shown in Fig. 13, in the case of a winter tire that prioritizes performance on snow, the height h2 is preferably 20% to 40% of the maximum depth d1 of the closed sipe 8. On the other hand, in the case of an all-season tire that is intended for year-round use, the height h2 is preferably 50% to 70% of the depth d1. This allows performance according to the purpose of the tire to be obtained.

[0074] Furthermore, the height h2 of the third connecting portion 26c is, for example, 40% to 100% of the height h1 of the first connecting portion 26a or the second connecting portion 26b, and more preferably, the height h1 and the height h2 are the same, which further suppresses uneven wear.

[0075] The width W3 of the third connecting portion 26c (the width along the length of the closed sipe 8) is, for example, 10% to 50% of the length L12 of the third sipe piece 13 (the length along the length of the closed sipe 8), and preferably 20% to 30%. In a more desirable embodiment, the width W2 of the first connecting portion 26a and the second connecting portion 26b is the same as the width W3 of the third connecting portion 26c. This makes it possible to further suppress uneven wear around the closed sipe 8.

[0076] 15 and 16 are enlarged plan views of land portions of other embodiments of the present disclosure. In Fig. 15 and Fig. 16, the same reference numerals are used for the components described above, and the description thereof will be omitted here.

[0077] 15, a sipe adjacent to a longitudinal edge 6e of a block 6 in the tire circumferential direction is an unclosed sipe 9 that communicates with the longitudinal edge 6e. The unclosed sipe 9 of this embodiment has a shape in which, for example, a closed sipe 8 communicates with the longitudinal edge 6e at a first sipe piece 11 or a second sipe piece 12. Such a sipe arrangement helps to further improve braking / driving performance on ice.

[0078] 16, a block 6 is provided with a sipe group 7 in which closed sipes 8 are arranged diagonally with respect to the tire axial direction. Specifically, an imaginary straight line 18 (shown by a two-dot chain line) connecting a first end 8a of the closed sipe 8 provided at the end of the first side B1 in the tire axial direction and a second end 8b of the closed sipe 8 provided at the end of the second side B2 in the tire axial direction is, for example, at an angle of 10 to 45° with respect to the tire axial direction. This embodiment improves cornering performance, especially on ice.

[0079] The closed sipes 8 of the present disclosure are preferably provided at least in the shoulder blocks. The shoulder blocks are blocks included in the shoulder land portions located axially outermost in the tread portion 2 of the tire.

[0080] Generally, when braking on dry roads, a large load tends to act on the shoulder blocks, which tends to result in insufficient circumferential rigidity of the shoulder blocks. In other words, improving the circumferential rigidity of the shoulder blocks is important for improving braking performance on dry roads.

[0081] On the other hand, the closed sipes 8 of the present disclosure are expected to increase the rigidity of the blocks compared to conventional sipes. Therefore, by providing the closed sipes 8 of the present disclosure in the shoulder blocks, braking performance on dry roads can be effectively improved. In particular, the closed sipes 8 including the connecting portions 26 shown in FIG. 11 or 13 can reliably increase the rigidity of the blocks and further improve braking performance on dry roads.

[0082] Although a tire according to one embodiment of the present disclosure has been described in detail above, the present disclosure is not limited to the above-described specific embodiment and can be modified and implemented in various aspects. [Example]

[0083] A pneumatic tire of size 195 / 65R15 having the above-described sipe group was prototyped based on the specifications in Table 1. As a comparative example, a tire was prototyped in which a plurality of sipes b extending in a zigzag pattern were provided in block a, as shown in FIG. 17. Note that the sipes b of the comparative example extend linearly in their entirety in the radial direction of the tire. Note that each test tire has substantially the same configuration, except for the shape of the sipes. Each test tire was tested for traction performance on ice, braking performance on ice, and cornering performance on ice. The common specifications and test methods for each test tire are as follows: Rim: 15x6.0JJ Tire pressure: Front 230kPa, rear 230kPa Test vehicle: 1500cc, front-wheel drive Tire mounting position: All wheels

[0084] <Traction performance on ice> The traction performance of the test vehicle equipped with each test tire when traveling on icy roads was evaluated by the driver. The results were scored based on the traction performance of the comparative example being 100, with a higher score indicating better traction performance on ice.

[0085] <Braking performance on ice> The braking performance of the test vehicle equipped with each test tire when traveling on icy roads was evaluated by the driver. The results were scored based on the braking performance of the comparative example being 100, with a higher score indicating better braking performance on ice.

[0086] <Turning performance on ice> The cornering performance of the test vehicle fitted with each test tire when driven on an icy road was evaluated by the driver. The results were scored based on the cornering performance of the comparative example being 100, with a higher score indicating better cornering performance on ice. The test results are shown in Table 1.

[0087] [Table 1]

[0088] As a result of the test, it was confirmed that the tires of each example had improved braking / driving performance and cornering performance on ice compared to the comparative example.

[0089] [Note] The present disclosure includes the following aspects.

[0090] [Disclosure 1] A tire including a tread portion, The tread portion includes a land portion, A plurality of closed sipes having a width of 1.5 mm or less are arranged in the tire axial direction in the land portion, Each of the closed sipes includes a first end and a second end, a first sipe piece extending in the tire axial direction on the first end side, a second sipe piece extending in the tire axial direction on the second end side, and a third sipe piece inclined with respect to the tire axial direction between the first sipe piece and the second sipe piece, The closed sipes arranged in the tire axial direction overlap each other in the tire axial direction and the tire circumferential direction. tire. [Disclosure 2] The tire according to Disclosure 1, wherein the third sipe piece is inclined with respect to the tire axial direction at an angle greater than those of the first sipe piece and the second sipe piece. [Disclosure 3] The tire according to Disclosure 1 or 2, wherein the overlap length of the two closed sipes in the tire axial direction is 10% to 40% of the maximum length of the closed sipes in the tire axial direction. [Disclosure 4] A tire described in any one of Disclosures 1 to 3, wherein the angle between the first sipe piece and the third sipe piece and the angle between the second sipe piece and the third sipe piece are each 90° or greater. [Disclosure 5] the first sipe piece is continuous with a first side of the third sipe piece in the tire circumferential direction, the second sipe piece is continuous with a second side of the third sipe piece in the tire circumferential direction, the first end and the second end are located on a second side in the tire circumferential direction relative to the first sipe piece and on a first side in the tire circumferential direction relative to the second sipe piece, A tire described in any one of Disclosures 1 to 4, wherein the closed sipe includes a first outer sipe piece extending from the first end to the first sipe piece and a second outer sipe piece extending from the second end to the second sipe piece. [Disclosure 6] A tire described in the present disclosure 5, wherein the angle between the first sipe piece and the first outer sipe piece, and the angle between the second sipe piece and the second outer sipe piece are each 90° or greater. [Disclosure 7] In two axially adjacent closed sipes, The second sipe piece of the closed sipe on one side overlaps with the first sipe piece of the closed sipe on the other side in the tire axial direction, the second outer sipe piece of the closed sipe on one side extends from the second sipe piece to a first side in the tire circumferential direction, The tire according to Disclosure 5 or 6, wherein the first outer sipe piece of the closed sipe on the other side extends from the first sipe piece to a second side in the tire circumferential direction. [Disclosure 8] The tire according to any one of Disclosures 1 to 7, wherein the first sipe piece and the second sipe piece each extend at an angle in the range of ±10° with respect to the tire axial direction. [Disclosure 9] The tire according to any one of Disclosures 1 to 8, wherein the closed sipe includes, in a cross section of the sipe, a bent portion extending in a zigzag shape in the tire radial direction. [Disclosure 10] the first sipe piece is disposed on a first side in the tire circumferential direction relative to the second sipe piece, The first sipe piece and the second sipe piece are each configured as a bent portion extending in a zigzag shape in the tire radial direction in a sipe cross section, the bent portion includes an outer inclined portion that is connected to an edge of the closed sipe and extends inclined in one direction with respect to the tire radial direction, the outer inclined portion belonging to the first sipe piece inclines toward the first side in the tire circumferential direction toward the inner side in the tire radial direction, A tire described in any one of Disclosures 1 to 9, wherein the outer inclined portion belonging to the second sipe piece is inclined radially inward toward a second side in the tire circumferential direction opposite to the first side in the tire circumferential direction. [Disclosure 11] the first sipe piece is disposed on a first side in the tire circumferential direction relative to the second sipe piece and on a first side in the tire axial direction relative to the second sipe piece, the closed sipe includes a first outer sipe piece extending from the first end to the first sipe piece toward a first side in the tire circumferential direction, and a second outer sipe piece extending from the second end to the second sipe piece toward a second side in the tire circumferential direction opposite the first side in the tire circumferential direction, The first outer sipe piece and the second outer sipe piece are each configured as a bent portion extending in a zigzag shape in the tire radial direction in a sipe cross section, the bent portion includes an outer inclined portion that is connected to an edge of the closed sipe and extends inclined in one direction with respect to the tire radial direction, the outer inclined portion belonging to the first outer sipe piece inclines toward the first side in the tire axial direction toward the inner side in the tire radial direction, A tire described in any one of Disclosures 1 to 10, wherein the outer inclined portion belonging to the second outer sipe piece is inclined radially inward toward a second side in the tire axial direction opposite to the first side in the tire axial direction. [Disclosure 12] the first sipe piece is disposed on a first side in the tire circumferential direction relative to the second sipe piece and on a first side in the tire axial direction relative to the second sipe piece, the closed sipe includes a first outer sipe piece extending from the first end to the first sipe piece toward a first side in the tire circumferential direction, and a second outer sipe piece extending from the second end to the second sipe piece toward a second side in the tire circumferential direction opposite the first side in the tire circumferential direction, the first sipe piece, the second sipe piece, the third sipe piece, the first outer sipe piece, and the second outer sipe piece are each configured as a bent portion extending in a zigzag shape in the tire radial direction in a sipe cross section, the bent portion includes an outer inclined portion that is connected to an edge of the closed sipe and extends inclined in one direction with respect to the tire radial direction, the outer inclined portion belonging to the first sipe piece and the outer inclined portion belonging to the second sipe piece are each inclined toward a first side in the tire circumferential direction toward an inner side in the tire radial direction, the outer inclined portion belonging to the first outer sipe piece and the outer inclined portion belonging to the second outer sipe piece are each inclined toward the first side in the tire axial direction toward the inner side in the tire radial direction, A tire described in any one of disclosures 1 to 9, wherein the outer inclined portion belonging to the third sipe piece is inclined radially inward toward a second side in the tire axial direction opposite to the first side in the tire axial direction. [Disclosure 13] The tire according to any one of claims 9 to 12, wherein the bending portion includes at least two bending elements that are convex in the same direction. [Disclosure 14] The tire of disclosure 13, wherein the two bending elements have the same length in the tire radial direction. [Disclosure 15] The tire according to any one of claims 8 to 14, wherein the closed sipe includes a vertical portion that is continuous with the bent portion on the inner side in the tire radial direction and extends parallel to the tire radial direction. [Disclosure 16] The tire according to any one of Disclosures 1 to 8, wherein the entire closed sipe extends linearly in the tire radial direction in the sipe cross section. [Disclosure 17] The tire according to any one of Disclosures 1 to 16, wherein the closed sipe includes a connecting portion where opposing sipe walls are connected to each other and protrude radially outward in the tire radial direction. [Disclosure 18] The tire described in the present disclosure 17, wherein the connecting portion is provided on at least one of the first sipe piece and the second sipe piece. [Disclosure 19] The tire according to Disclosure 17 or 18, wherein the connecting portion is provided on both the first sipe piece and the second sipe piece. [This Disclosure 20] 20. The tire according to any one of claims 17 to 19, wherein the width of the connecting portion along the length direction of the closed sipe is 10% to 50% of the length of the first sipe piece. [Disclosure 21] The tire according to any one of claims 17 to 20, wherein the height of the connecting portion in the tire radial direction is 10% to 90% of the maximum depth of the closed sipe. [Disclosure 22] the connecting portion is provided on both the first sipe piece and the second sipe piece, A tire described in any one of disclosures 17 to 21, wherein the radial height of the connecting portion provided on the first sipe piece is the same as the radial height of the connecting portion provided on the second sipe piece. [Disclosure 23] the tread portion includes a shoulder land portion disposed axially outermost on the tire; The shoulder land portion includes a plurality of shoulder blocks divided by a plurality of lateral grooves extending in the tire axial direction, The tire according to any one of the disclosures 1 to 22, wherein the shoulder block is provided with a plurality of the closed sipes.

Claims

1. A tire including a tread portion, The tread portion includes a land portion, A plurality of closed sipes having a width of 1.5 mm or less are arranged in the tire axial direction in the land portion, Each of the closed sipes includes a first end and a second end, a first sipe piece extending in the tire axial direction on the first end side, a second sipe piece extending in the tire axial direction on the second end side, and a third sipe piece inclined with respect to the tire axial direction between the first sipe piece and the second sipe piece, The closed sipes arranged in the tire axial direction overlap each other in the tire axial direction and the tire circumferential direction, The overlap length of the two closed sipes in the tire axial direction is 10% to 40% of the maximum length of the closed sipes in the tire axial direction. tire.

2. A tire including a tread portion, The tread portion includes a land portion, A plurality of closed sipes having a width of 1.5 mm or less are arranged in the tire axial direction in the land portion, Each of the closed sipes includes a first end and a second end, a first sipe piece extending in the tire axial direction on the first end side, a second sipe piece extending in the tire axial direction on the second end side, and a third sipe piece inclined with respect to the tire axial direction between the first sipe piece and the second sipe piece, The closed sipes arranged in the tire axial direction overlap each other in the tire axial direction and the tire circumferential direction, the first sipe piece is continuous with a first side of the third sipe piece in the tire circumferential direction, the second sipe piece is continuous with a second side of the third sipe piece in the tire circumferential direction, the first end and the second end are located on a second side in the tire circumferential direction relative to the first sipe piece and on a first side in the tire circumferential direction relative to the second sipe piece, The closed sipe includes a first outer sipe piece extending from the first end to the first sipe piece and a second outer sipe piece extending from the second end to the second sipe piece. tire.

3. In two axially adjacent closed sipes of the tire, the second sipe piece of the closed sipe on one side overlaps with the first sipe piece of the closed sipe on the other side in the tire axial direction, the second outer sipe piece of the closed sipe on one side extends from the second sipe piece to a first side in the tire circumferential direction, The tire according to claim 2 , wherein the first outer sipe piece of the other closed sipe extends from the first sipe piece to a second side in the tire circumferential direction.

4. A tire as described in any one of claims 1 to 3, wherein the closed sipe includes a folded portion in the sipe cross section that extends in a zigzag pattern in the radial direction of the tire.

5. A tire including a tread portion, The tread portion includes a land portion, A plurality of closed sipes having a width of 1.5 mm or less are arranged in the tire axial direction in the land portion, Each of the closed sipes includes a first end and a second end, a first sipe piece extending in the tire axial direction on the first end side, a second sipe piece extending in the tire axial direction on the second end side, and a third sipe piece inclined with respect to the tire axial direction between the first sipe piece and the second sipe piece, The closed sipes arranged in the tire axial direction overlap each other in the tire axial direction and the tire circumferential direction, the first sipe piece is disposed on a first side in the tire circumferential direction relative to the second sipe piece, The first sipe piece and the second sipe piece are each configured as a bent portion extending in a zigzag shape in the tire radial direction in a sipe cross section, the bent portion includes an outer inclined portion that is connected to an edge of the closed sipe and extends inclined in one direction with respect to the tire radial direction, the outer inclined portion belonging to the first sipe piece inclines toward the first side in the tire circumferential direction toward the inner side in the tire radial direction, the outer inclined portion belonging to the second sipe piece is inclined radially inward toward a second side in the tire circumferential direction opposite to the first side in the tire circumferential direction, tire.

6. A tire including a tread portion, The tread portion includes a land portion, A plurality of closed sipes having a width of 1.5 mm or less are arranged in the tire axial direction in the land portion, Each of the closed sipes includes a first end and a second end, a first sipe piece extending in the tire axial direction on the first end side, a second sipe piece extending in the tire axial direction on the second end side, and a third sipe piece inclined with respect to the tire axial direction between the first sipe piece and the second sipe piece, The closed sipes arranged in the tire axial direction overlap each other in the tire axial direction and the tire circumferential direction, the first sipe piece is disposed on a first side in the tire circumferential direction relative to the second sipe piece and on a first side in the tire axial direction relative to the second sipe piece, the closed sipe includes a first outer sipe piece extending from the first end to the first sipe piece toward a first side in the tire circumferential direction, and a second outer sipe piece extending from the second end to the second sipe piece toward a second side in the tire circumferential direction opposite the first side in the tire circumferential direction, The first outer sipe piece and the second outer sipe piece are each configured as a bent portion extending in a zigzag shape in the tire radial direction in a sipe cross section, the bent portion includes an outer inclined portion that is connected to an edge of the closed sipe and extends inclined in one direction with respect to the tire radial direction, the outer inclined portion belonging to the first outer sipe piece inclines toward the first side in the tire axial direction toward the inner side in the tire radial direction, the outer inclined portion belonging to the second outer sipe piece is inclined radially inwardly toward a second side in the tire axial direction opposite to the first side in the tire axial direction, tire.

7. A tire described in any one of claims 4 to 6, wherein the bending portion includes at least two bending elements that are convex in the same direction.

8. A tire described in any one of claims 1 to 7, wherein the third sipe piece is inclined relative to the tire axial direction at an angle greater than that of the first sipe piece and the second sipe piece.

9. A tire described in any one of claims 1 to 8, wherein the angle between the first sipe piece and the third sipe piece, and the angle between the second sipe piece and the third sipe piece are each 90° or greater.

10. A tire described in any one of claims 1 to 9, wherein the first sipe piece and the second sipe piece each extend at an angle in the range of ±10° relative to the tire axial direction.

11. A tire as described in any one of claims 1 to 10, wherein the closed sipe includes a connecting portion where opposing sipe walls are connected and protrude radially outward from the tire.

12. A tire as described in claim 11, wherein the connecting portion is provided on at least one of the first sipe piece and the second sipe piece.

13. A tire as described in claim 11 or 12, wherein the radial height of the connecting portion is 10% to 90% of the maximum depth of the closed sipe.

14. The tread portion includes a shoulder land portion disposed axially outermost on the tire, The shoulder land portion includes a plurality of shoulder blocks divided by a plurality of lateral grooves extending in the tire axial direction, The tire according to claim 1 , wherein the shoulder block is provided with a plurality of the closed sipes.

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