tire

Abstract

To provide a tire further improved in partial abrasion resistance performance while retaining traveling performance in a low μ road.SOLUTION: A tire 1 includes a first land part 3. The first land part 3 comprises ribs. The first land part 3 comprises a first sipe 4, and a second sipe 5 adjacent to the first sipe 4 in the tire circumferential direction. The first sipe 4 comprises a pair of first shallow bottom portions 6, and a first deep bottom portion 7 for connecting the pair of first shallow bottom portions 6, 6. The second sipe 5 comprises a pair of second deep bottom portions 8, and a second shallow bottom portion 9 for connecting the pair of second deep bottom portions 8, 8. The first deep bottom portion 7 and the second deep bottom portion 8 are position-deviated in the tire axial direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 below describes a pneumatic tire in which a land portion is provided with a first lateral groove and a sipe. The first lateral groove has an inner end that extends from a first circumferential edge of the land portion and terminates within the land portion. A tie bar is provided at the inner end. The sipe includes a first sipe portion that extends from a second circumferential edge of the land portion to the first lateral groove and a second sipe portion that extends over the tie bar. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-88344 Summary of the Invention [Problem to be solved by the invention]

[0004] Although the above-described tires can ensure traction on low μ roads, there is still room for improvement in uneven wear resistance.

[0005] The present disclosure has been devised in consideration of the above-described circumstances, and has as its main object to provide a tire that can further improve uneven wear resistance while maintaining driving performance on low μ roads. [Means for solving the problem]

[0006] The present disclosure relates to a tire having a tread portion, the tread portion including a first land portion including a first circumferential edge extending in the tire circumferential direction, a second circumferential edge extending in the tire circumferential direction, and a tread surface therebetween, the first land portion being made of a rib that is not provided with a lateral groove (defined as having a width of 2 mm or more) that completely crosses the first land portion in the tire axial direction, and the first land portion is provided with a first sipe extending in the tire axial direction, and a second sipe extending in the tire axial direction and adjacent to the first sipe in the tire circumferential direction. The tire includes two sipes, wherein the first sipes include a pair of first shallow bottom portions that include both longitudinal ends, and a first deep bottom portion that connects the pair of first shallow bottom portions and has a depth greater than that of the pair of first shallow bottom portions, and the second sipes include a pair of second deep bottom portions that include both longitudinal ends, and a second shallow bottom portion that connects the pair of second deep bottom portions and has a depth less than that of the pair of second deep bottom portions, and the first deep bottom portion and the pair of second deep bottom portions are misaligned in the tire axial direction. [Effects of the Invention]

[0007] By employing the above-described configuration, the tire of the present disclosure can further improve uneven wear resistance while maintaining driving performance on low μ roads. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a plan view of a first land portion according to an embodiment of the present disclosure. [Figure 2] 2A is a cross-sectional view taken along line AA in FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB in FIG. [Figure 3] FIG. 2 is a development view of the entire tread portion. [Figure 4] 4A is a cross-sectional view taken along line CC in FIG. 3, and FIG. 4B is a cross-sectional view taken along line DD in FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. 1 is an expanded plan view of the tread portion 2 of a tire 1 according to this embodiment. The present disclosure is applied to an all-season pneumatic tire mounted on a light truck that can run on paved roads such as asphalt roads as well as low-μ roads such as steel roads and icy roads. The present disclosure may also be applied to pneumatic tires 1 for passenger cars and heavy-duty vehicles, as well as tires 1 in other categories.

[0010] As shown in FIG. 1, the tread portion 2 of this embodiment includes a first land portion 3 including a first circumferential edge e1 extending in the tire circumferential direction, a second circumferential edge e2 extending in the tire circumferential direction, and a tread surface 3a therebetween.

[0011] The first land portion 3 is formed by a rib 3R that does not have a lateral groove that completely crosses the first land portion 3 in the tire axial direction. Such a first land portion 3 has a relatively large contact area, improving driving performance on low μ roads. In this specification, the lateral groove is a groove-like body with a groove width of 2 mm or more. In addition, in this specification, the sipe, which will be described later, is a notch-like body with a width of less than 2 mm.

[0012] The first land portion 3 is provided with first sipes 4 extending in the tire axial direction and second sipes 5 extending in the tire axial direction and adjacent to the first sipes 4 in the tire circumferential direction. Such first sipes 4 and second sipes 5 generate a large scratching force on low μ roads, thereby maintaining basic driving performance on low μ roads. In the first land portion 3 of this embodiment, the first sipes 4 and second sipes 5 are arranged alternately in the tire circumferential direction.

[0013] Fig. 2(a) is a cross-sectional view taken along line AA in Fig. 1. Fig. 2(b) is a cross-sectional view taken along line BB in Fig. 1. As shown in Figs. 1 and 2, the first sipe 4 includes a pair of first shallow portions 6, 6 that include both longitudinal ends 4e, and a first deep portion 7 that connects the pair of first shallow portions 6, 6 and has a depth d2 that is greater than the depth d1 of the pair of first shallow portions 6. The second sipe 5 includes a pair of second deep portions 8, 8 that include both longitudinal ends 5e, and a second shallow portion 9 that connects the pair of second deep portions 8, 8 and has a depth d4 that is less than the depth d3 of the pair of second deep portions 8.

[0014] The first deep bottom portion 7 and the pair of second deep bottom portions 8 are misaligned in the tire axial direction. This prevents a large difference in rigidity from occurring between the first sipe 4 and the second sipe 5 of the first land portion 3, improving uneven wear resistance.

[0015] More specifically, in this embodiment, the first deep portion 7 has no portion that coincides with the pair of second deep portions 8 in the tire axial direction. This allows the above-mentioned effect to be effectively achieved. If the first deep portion 7 and the pair of second deep portions 8 are separated too far in the tire axial direction, for example, the axial length L2 of the first shallow portion 6 becomes large and the axial length L3 of the first deep portion 7 becomes small, which may result in the scratching force not being exerted over a long period of time. For this reason, the axial separation distance La between the first deep portion 7 and the second deep portion 8 is preferably 2% or more of the maximum axial width Wa of the first land portion 3, more preferably 3% or more, more preferably 7% or less, and even more preferably 6% or less.

[0016] 3 is a plan view showing the area between the tread ends Te and Te of the tread portion 2 of this embodiment. The "tread end Te" is defined as the axially outermost contact point of the tire when the tire 1 is in a normal state and is placed on a flat surface with a normal load and a camber angle of 0 degrees. The axial distance between the tread ends Te and Te is the tread width TW.

[0017] The "normal state" refers to a state in which the tire 1 is mounted on a normal rim (not shown), inflated to a normal internal pressure, and no load is applied. Unless otherwise specified, the dimensions of each part of the tire 1 are values ​​measured in this normal state.

[0018] The "genuine rim" is the rim that is defined for each tire by each standard in the standard system that includes the standard on which the tire is based, and is called a "standard rim" in the case of JATMA, a "design rim" in the case of TRA, and a "measuring rim" in the case of ETRTO.

[0019] The "normal internal pressure" refers to the air pressure specified for each tire by each standard in the standard system, including the standard 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," and in the case of ETRTO, it is the "INFLATION PRESSURE."

[0020] The "normal load" mentioned above is the load determined for each tire by each standard in the standard system, including the standard on which the tire is based. In the case of JATMA, it is the "maximum load capacity," in the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and in the case of ETRTO, it is the "LOAD CAPACITY."

[0021] As shown in FIG. 3, the tread portion 2 of this embodiment includes a plurality of main grooves 10 extending continuously in the tire circumferential direction, and land portions 11 separated by the main grooves 10.

[0022] The main grooves 10 of this embodiment include a pair of shoulder main grooves 10A located closest to the tread edge Te and one crown main groove 10B located between the pair of shoulder main grooves 10A. As a result, the land portion 11 of this embodiment includes a pair of shoulder land portions 12 defined between the shoulder main groove 10A and the tread edge Te, and a pair of crown land portions 13 defined between the shoulder main groove 10A and the crown main groove 10B.

[0023] In this embodiment, the first land portion 3 is a crown land portion 13. The crown land portion 13 is a land portion that is subjected to a larger ground contact pressure during straight driving than the shoulder land portions 12. By configuring such a crown land portion 13 as the first land portion 3 consisting of a rib, high driving performance is achieved on low μ roads. In the rest of this specification, the first land portion 3 will be described as the crown land portion 13. Note that the first land portion 3 may form the shoulder land portion 12.

[0024] In this embodiment, the shoulder main grooves 10A and crown main grooves 10B extend in a zigzag pattern along the tire circumferential direction. Because these shoulder main grooves 10A and crown main grooves 10B have an axial component, they exert a scratching force on low-μ roads. The shoulder main grooves 10A and crown main grooves 10B are formed with, for example, the same number of zigzag pitches. The shoulder main grooves 10A and crown main grooves 10B may extend in a wavy or arcuate pattern, or may extend linearly.

[0025] The groove width W2 of the crown main groove 10B is formed to be larger than the groove width W1 of the shoulder main groove 10A, for example. Although not particularly limited, in this embodiment, the groove width W1 of the shoulder main groove 10A and the groove width W2 of the crown main groove 10B are preferably 2% or more of the tread width TW, more preferably 3% or more, more preferably 7% or less, and even more preferably 6% or less.

[0026] 4(a) is a cross-sectional view taken along line CC in FIG. 3. FIG. 4(b) is a cross-sectional view taken along line DD in FIG. 3. As shown in FIG. 4, the angle θ1 of the groove wall 10a of the shoulder main groove 10A relative to the tread normal n is preferably 4 degrees or more, more preferably 8 degrees or more, and more preferably 20 degrees or less, and even more preferably 16 degrees or less. The angle θ2 of the groove wall 10b of the crown main groove 10B relative to the tread normal n is preferably 4 degrees or more, more preferably 8 degrees or more, and even more preferably 20 degrees or less, and even more preferably 16 degrees or less. This reduces stone trapping in each of the main grooves 10A and 10B. In this specification, the tread normal n extends in a direction perpendicular to the tread surfaces 12a and 13a of the land portions 12 and 13.

[0027] In this embodiment, protrusions 14 that protrude radially outward are provided at the groove bottoms of the crown main grooves 10B. These protrusions 14 further suppress stone trapping. The protrusions 14 are spaced apart along the longitudinal direction of the crown main grooves 10B. In this embodiment, no protrusions are provided at the groove bottoms of the shoulder main grooves 10A.

[0028] Fig. 5 is an enlarged view of the crown land portion 13 in Fig. 3. As shown in Fig. 5, the first circumferential edge e1 is, for example, an edge where the groove wall 10a (shown in Fig. 4) of the shoulder main groove 10A intersects with the tread surface 13a of the crown land portion 13. The second circumferential edge e2 is, for example, an edge where the groove wall 10b of the crown main groove 10B intersects with the tread surface 13a.

[0029] The first circumferential edge e1 and the second circumferential edge e2 have, for example, a plurality of peaks 15 that are convex toward the outside of the crown land portion 13 in a plan view of the tread. Furthermore, the first circumferential edge e1 and the second circumferential edge e2 include, for example, a plurality of recessed portions 16 that are recessed toward the inside of the first land portion 3 in a plan view of the tread. In this embodiment, the first circumferential edge e1 and the second circumferential edge e2 each have peaks 15 and recessed portions 16 that are alternately provided in the tire circumferential direction. The peaks 15 and recessed portions 16 coincide with the zigzag peaks of the shoulder main grooves 10A and the crown main grooves 10B, respectively.

[0030] In a plan view of the tread, each of the apexes 15 is formed by an arc S having a radius of curvature r1 of 2 mm or more. This increases the rigidity of the portion of the crown land portion 13 where high ground contact pressure acts (the apex 15), thereby improving uneven wear resistance. Although not particularly limited, the radius of curvature r1 is preferably 5 mm or less.

[0031] The crown land portion 13 is formed with a plurality of first lateral grooves 17, each extending from the first circumferential edge e1 and having an end 17e terminated within the crown land portion 13. The crown land portion 13 is also formed with a plurality of second lateral grooves 18, each extending from the second circumferential edge e2 and having an end 18e terminated within the crown land portion 13. In this manner, in this embodiment, the first lateral grooves 17 are connected to the shoulder main grooves 10A. In this embodiment, the second lateral grooves 18 are connected to the crown main grooves 10B.

[0032] In this embodiment, the first sipes 4 extend from the discontinuous end 17e to the second circumferential edge e2. In this embodiment, the second sipes 5 extend from the discontinuous end 18e to the first circumferential edge e1. In this manner, the first sipes 4 are connected to the crown main groove 10B. The second sipes 5 are connected to the shoulder main groove 10A.

[0033] The first sipe 4 is connected to, for example, the apex 15 of the second circumferential edge e2. The second sipe 5 is connected to, for example, the apex 15 of the first circumferential edge e1. In this way, the first sipe 4 and the second sipe 5 are connected to the apex 15 formed by the arc S, so that a decrease in the rigidity of the crown land portion 13 is suppressed.

[0034] In this embodiment, the first sipes 4 and the second sipes 5 extend linearly. For example, the first sipes 4 are inclined in the same direction as the second sipes 5 with respect to the tire axial direction. This reduces the rigidity difference in the crown land portion 13 between the first sipes 4 and the second sipes 5, thereby suppressing the occurrence of uneven wear. Note that the first sipes 4 and the second sipes 5 may extend in a zigzag pattern along the longitudinal direction or along the tire radial direction, for example.

[0035] In order to effectively exert the above-mentioned effects, the absolute value |α1-α2| of the difference between the angle α1 of the first sipe 4 relative to the tire axial direction and the angle α2 of the second sipe 5 relative to the tire axial direction is preferably 20 degrees or less, and more preferably 10 degrees or less. Although not particularly limited, the angle α1 of the first sipe 4 and the angle α2 of the second sipe 5 are preferably 10 to 30 degrees.

[0036] The axial length L1 of the first sipe 4 is preferably 20% or more, more preferably 30% or more, and preferably 80% or less, and more preferably 70% or less of the maximum width Wa (shown in FIG. 1) of the crown land portion 13. Similarly, the axial length L4 of the second sipe 5 is preferably 20% or more, more preferably 30% or more, and preferably 80% or less, and more preferably 70% or less of the maximum width Wa of the first land portion 3.

[0037] The pair of first shallow bottom portions 6, 6 includes, for example, a lateral-groove-side first shallow bottom portion 6A connected to the first lateral groove 17. The axial length L2a of the lateral-groove-side first shallow bottom portion 6A is preferably 10% or more of the maximum radial thickness h1 (shown in FIG. 2) of the crown land portion 13. This ensures a space between the first deep bottom portion 7 and the first lateral groove 17, reduces the rigidity step in the axial outer region of the crown land portion 13, where a relatively large lateral force acts, and suppresses uneven wear originating from the first lateral groove 17. If the length L2a of the lateral-groove-side first shallow bottom portion 6A is excessively large, the axial length L3 of the first deep bottom portion 7 becomes short, which shortens the length of the first sipe 4 at the end of wear, potentially making it difficult to maintain driving performance on low-μ roads. Therefore, the length of the lateral groove-side first shallow bottom portion 6A is more preferably 15% or more of the maximum thickness h1 of the first land portion 3, more preferably 30% or less, and even more preferably 25% or less.

[0038] One axially (right side in FIG. 5) 6A of the pair of first shallow portions 6, in other words, the lateral-groove-side first shallow portion 6A, for example, overlaps in the tire axial direction with the other axially (left side in FIG. 5) 8B of the pair of second deep portions 8. This suppresses the occurrence of a rigidity step.

[0039] The first deep bottom portion 7 has a length greater than that of the first shallow bottom portion 6. The second shallow bottom portion 9 has a length greater than that of the second deep bottom portion 8. As a result, the rigidity near the first sipe 4 tends to be smaller than the rigidity near the second sipe 5. Therefore, by making the width W3 of the first sipe 4 smaller than the width W4 of the second sipe 5, the difference in rigidity between the first sipe 4 and the second sipe 5 is reduced, thereby improving uneven wear resistance. To effectively exert this effect, the width W3 of the first sipe 4 is desirably 50% or more of the width W4 of the second sipe 5, more desirably 55% or more, desirably 75% or less, and even more desirably 70% or less. The width W3 of the first sipe 4 is desirably 0.4 mm or more, more desirably 0.6 mm or more, desirably 0.9 mm or less, and even more desirably 0.7 mm or less.

[0040] The axial length L3 of the first deep bottom portion 7 is preferably 30% or more, more preferably 40% or more, more preferably 70% or less, and even more preferably 60% or less of the axial length L1 of the first sipe 4. The axial length L6 of the second shallow bottom portion 9 is preferably 30% or more, more preferably 40% or more, more preferably 70% or less, and even more preferably 60% or less of the axial length L4 of the second sipe 5.

[0041] As shown in Figure 2, the depth d1 of the first shallow portion 6 and the depth d4 of the second shallow portion 9 are preferably 10% or more of the maximum thickness h1 of the crown land portion 13, more preferably 20% or more, and more preferably 50% or less, and even more preferably 40% or less. Because the depth d1 of the first shallow portion 6 and the depth d4 of the second shallow portion 9 are 10% or more of the maximum thickness h1 of the crown land portion 13, scratching resistance on low μ roads is maintained. Because the depth d1 of the first shallow portion 6 and the depth d4 of the second shallow portion 9 are 50% or less of the maximum thickness h1 of the crown land portion 13, a significant decrease in rigidity of the crown land portion 13 is suppressed.

[0042] The depth d2 of the first deep bottom portion 7 and the depth d3 of the second deep bottom portion 8 are preferably 70% or more of the maximum thickness h1 of the crown land portion 13, more preferably 75% or more, and more preferably 90% or less, and even more preferably 85% or less. Because the depth d2 of the first deep bottom portion 7 and the depth d3 of the second deep bottom portion 8 are 70% or more of the maximum thickness h1 of the crown land portion 13, the scratching force on low μ roads is maintained until the end of wear of the tire 1. Because the depth d2 of the first deep bottom portion 7 and the depth d3 of the second deep bottom portion 8 are 90% or less of the maximum thickness h1 of the crown land portion 13, rigidity between the first sipe 4 and the second sipe 5 is maintained.

[0043] Fig. 6 is an enlarged view of the crown land portion 13 in Fig. 3. As shown in Fig. 6, in this embodiment, the first lateral grooves 17 and the second lateral grooves 18 are alternately provided in the tire circumferential direction. The shortest circumferential distance L7 between the first lateral grooves 17 and the second lateral grooves 18 is preferably 30% or more, more preferably 40% or more, more preferably 70% or less, and even more preferably 60% or less of the circumferential distance L8 between the first lateral grooves 17, 17. Because the shortest distance L7 is 30% or more and 70% or less of the circumferential distance L8 between the first lateral grooves 17, 17, the bias in rigidity of the crown land portion 13 is reduced, and uneven wear resistance is improved.

[0044] In this embodiment, the first lateral grooves 17 and the second lateral grooves 18 are inclined relative to the tire axial direction. The first lateral grooves 17 and the second lateral grooves 18 are inclined, for example, in the same direction. Such first lateral grooves 17 and second lateral grooves 18 also have a circumferential component, improving snow performance during cornering and driving performance on low-μ roads. The absolute value |α3-α4| of the difference between the angle α3 of the first lateral groove 17 relative to the tire axial direction and the angle α4 of the second lateral groove 18 relative to the tire axial direction is preferably 20 degrees or less, and more preferably 10 degrees or less. This improves uneven wear resistance.

[0045] The first lateral grooves 17 are, for example, inclined in the same direction as the first sipes 4 relative to the tire axial direction. Such first lateral grooves 17 enhance the edge effect of the first sipes 4. The absolute value |α1-α3| of the difference between the angle α3 of the first lateral grooves 17 and the angle α1 of the first sipes 4 (shown in FIG. 5) is preferably 20 degrees or less, and more preferably 10 degrees or less. In this embodiment, the absolute value |α1-α3| is 0 degrees. Similarly, the absolute value |α2-α4| of the difference between the angle α4 of the second lateral grooves 18 and the angle α2 of the second sipes 5 is preferably 20 degrees or less, and more preferably 10 degrees or less.

[0046] The first lateral grooves 17 are connected to the recessed portions 16 of the first circumferential edge e1, for example. The second lateral grooves 18 are connected to the recessed portions 16 of the second circumferential edge e2, for example. The first lateral grooves 17 and the second lateral grooves 18 eliminate the rigidity step of the recessed portions 16 and improve wear resistance.

[0047] The axial length L9 of the first lateral groove 17 and the axial length L10 of the second lateral groove 18 are each preferably 20% or more of the maximum width Wa of the crown land portion 13, more preferably 30% or more, and more preferably 70% or less, and even more preferably 60% or less.

[0048] Although not particularly limited, the groove width W5 of the first transverse groove 17 and the groove width W6 of the second transverse groove 18 are, for example, 10% to 20% of the maximum length Wa of the crown land portion 13.

[0049] In this embodiment, the first lateral groove 17 includes a first raised portion 20 where the groove bottom 17s is raised. The second lateral groove 18 includes a second raised portion 21 where the groove bottom 18s is raised. The first raised portion 20 extends from the discontinuous end 17e toward the shoulder main groove 10A and terminates without connecting to the shoulder main groove 10A. The second raised portion 21 extends from the discontinuous end 18e toward the crown main groove 10B and terminates without connecting to the crown main groove 10B.

[0050] The axial length L11 of the first raised portion 20 is preferably 70% or more of the length L9 of the first lateral groove 17, more preferably 75% or more, and more preferably 90% or less, and even more preferably 85% or less. The axial length L12 of the second raised portion 21 is preferably 70% or more of the length L10 of the second lateral groove 18, more preferably 75% or more, and more preferably 90% or less, and even more preferably 85% or less. The depth d7 (shown in FIG. 2) of the first raised portion 20 and the depth d8 of the second raised portion 21 are each preferably 30% or more of the maximum thickness h1 of the crown land portion 13, more preferably 40% or more, and more preferably 70% or less, and even more preferably 60% or less.

[0051] The second raised portion 21 is provided with a groove bottom sipe 24 that connects to the second sipe 5. On the other hand, the first raised portion 20 is not provided with a groove bottom sipe. This maintains a higher rigidity in the axially outer region of the crown land portion 13, suppressing uneven wear originating from the first lateral groove 17. In addition, during straight-ahead driving, the deformation of the second lateral groove 18, which is located axially inside the crown land portion 13 and receives a large ground contact pressure, is promoted, further increasing the scratching force and improving driving performance on low μ roads.

[0052] As shown in Fig. 3, the crown land portion 13 is provided with closed sipes 26 whose ends 26e, 26e are discontinued within the crown land portion 13. The closed sipes 26 extend, for example, in a zigzag pattern. In this embodiment, the closed sipes 26 are provided between first sipes 4 and second sipes 5 that are arranged alternately in the tire circumferential direction. For example, one closed sipe 26 is provided between each first sipe 4 and second sipe 5.

[0053] The axial length L13 of the closed sipe 26 is preferably 30% or more of the maximum length Wa (shown in FIG. 1) of the crown land portion 13, more preferably 35% or more, and more preferably 50% or less, and even more preferably 45% or less. Because the length L13 of the closed sipe 26 is 30% or more of the maximum length Wa of the crown land portion 13, driving performance on low μ roads is improved. Because the length 135 of the closed sipe 26 is 50% or less of the maximum length Wa of the crown land portion 13, high wear resistance is maintained.

[0054] The closed sipes 26 are inclined, for example, with respect to the tire axial direction. In this embodiment, the closed sipes 26 are inclined in the same direction as the first sipes 4. The absolute value |α1-α5| of the difference between the angle α5 of the closed sipes 26 with respect to the tire axial direction and the angle α1 of the first sipes 4 (shown in FIG. 5) is preferably 20 degrees or less, and more preferably 10 degrees or less. In this embodiment, the absolute value |α1-α5| is 0 degrees. The angle α5 of the closed sipes 26 is the angle at the center line of the zigzag amplitude.

[0055] The maximum width Wa of the crown land portion 13 is preferably smaller than the maximum width Wb (shown in FIG. 7) of the shoulder land portion 12. The maximum width Wa of the crown land portion 13 is preferably 30% or more of the maximum width Wb of the shoulder land portion 12, more preferably 40% or more, and preferably 90% or less, and more preferably 80% or less. The maximum width Wa of the crown land portion 13 is preferably 15% or more of the tread width TW, more preferably 20% or more, and preferably 35% or less, and more preferably 30% or less.

[0056] FIG. 7 is a plan view of the shoulder land portion 12. As shown in FIG. 7, the shoulder land portion 12 is provided with shoulder lateral grooves 35 that cross the shoulder land portion 12 and shoulder sipes 36 that connect to the shoulder main grooves 10A. As a result, the shoulder land portion 12 is divided into multiple shoulder blocks 12B by the shoulder main grooves 10A, the tread edge Te, and the shoulder lateral grooves 35. The shoulder lateral grooves 35 connect to zigzag apexes 38A that convex outward in the axial direction of the shoulder main grooves 10A. The shoulder sipes 36 connect to zigzag apexes 38b that convex inward in the axial direction of the shoulder main grooves 10A. The shape of the shoulder land portion 12 is not limited to this embodiment; for example, the shoulder sipes 36 may not be provided.

[0057] The shoulder lateral grooves 35 have a groove width W7 that increases continuously toward the tread edge Te. The shoulder lateral grooves 35 extend, for example, along the tire axial direction. The groove depth (not shown) of the shoulder lateral grooves is preferably 30% or less, and more preferably 25% or less, of the groove depth D1 (same as the maximum thickness h1 of the crown land portion 13) of the shoulder main grooves 10A. Such shoulder lateral grooves 35 prevent excessive reduction in the rigidity of the shoulder land portion 12. To ensure the basic performance of the tire 1, the groove depth of the shoulder lateral grooves 35 is preferably 5% or more, and more preferably 10% or more, of the groove depth of the shoulder main grooves 10A.

[0058] The shoulder lateral groove 35 includes a first widened portion 35A extending from the shoulder main groove 10A and a second widened portion 35B having a larger change in groove width W7 relative to the longitudinal direction than the first widened portion 35A. The axial length L15 of the second widened portion 35B is preferably 10% or more of the maximum width Wb of the shoulder land portion 12, more preferably 15% or more, and more preferably 30% or less, and even more preferably 25% or less.

[0059] In this embodiment, the shoulder sipe 36 includes an axial portion 36A extending from the shoulder main groove 10A in the tire axial direction, and a circumferential portion 36B connecting to the axial portion 36A and extending in the tire circumferential direction. In a plan view of the tread, the shoulder sipe 36 is formed in a substantially L-shape. The circumferential portion 36B does not connect to the shoulder lateral groove 35 and terminates within the shoulder block 12B. One shoulder sipe 36 is provided in each shoulder block 12B.

[0060] The shoulder sipes 36 are terminated, for example, axially inward of the second widened portion 35B. In this embodiment, the shoulder sipes 36 extend toward the tread edge Te from an axially intermediate position 12c of the shoulder land portion 12. In this specification, the intermediate position 12c is the middle of the maximum width Wb. The distance L16 between the axially outer end 36e of the shoulder sipe 36 and the tread edge Te is preferably 30% or more of the maximum width Wb of the shoulder land portion 12, more preferably 35% or more, more preferably less than 50%, and even more preferably 45% or less.

[0061] The land ratio of the shoulder land portion 12 is preferably 70% or more, more preferably 75% or more, and is preferably 90% or less, and even more preferably 85% or less. The land ratio is the ratio (Sb / Sa) of the tread area Sb of the shoulder land portion 12 to the virtual tread area Sa of the shoulder land portion 12 obtained by filling all the lateral grooves and sipes provided in the shoulder land portion 12, such as the shoulder lateral grooves 35 and shoulder sipes 36.

[0062] The maximum circumferential length L18 of the shoulder block 12B is preferably 75% or more of the circumferential separation distance L8 between the first lateral grooves 17, 17, more preferably 80% or more, and is preferably 95% or less, and even more preferably 90% or less.

[0063] Although particularly preferred embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the illustrated embodiments and can be modified and implemented in various forms. [Example]

[0064] Tires having the basic pattern shown in Figure 3 were prototyped based on the specifications in Tables 1 and 2. Each test tire was then tested for running performance on low μ roads and uneven wear resistance. The common specifications and test methods for each test tire are as follows: Tire size: 205 / 85R16 117 / 115L Rim size: 16 x 5.5J Air pressure: 600kPa (front and rear wheels) Load: Empty

[0065] <Driving performance on low-μ roads> The test tires were mounted on all wheels of a 3000cc light truck. A test driver drove the vehicle on iron and icy roads, and evaluated the driving performance on each road surface while driving straight and while cornering. The results were expressed as a score with Example 1 being 100. The higher the score, the better the driving performance on low μ roads.

[0066] <Uneven wear resistance> A test driver drove the vehicle on a dry asphalt road surface. The test driver then evaluated the occurrence of uneven wear (heel-and-toe wear, etc.) on the crown land portion by sensory evaluation. The results are expressed as a score based on Example 1 being 100. The larger the score, the more the occurrence of uneven wear is suppressed and the better the uneven wear resistance performance. Mileage: 20,000km The test results are shown in Tables 1 and 2. In Table 1, an entry of "-1" for La / Wa indicates that the first deep bottom portion and the second deep bottom portion are not misaligned in the tire axial direction. In each case, a score of 95 or above is a pass, and a score below 95 is a fail.

[0067] [Table 1]

[0068] [Table 2]

[0069] The tires of the examples have improved wear resistance compared to the tires of the comparative examples. In addition, the tires of the examples have excellent running performance on low μ roads.

[0070] [Note] The present disclosure includes the following aspects.

[0071] [Disclosure 1] A tire having a tread portion, the tread portion includes a first land portion including a first circumferential edge extending in the tire circumferential direction, a second circumferential edge extending in the tire circumferential direction, and a tread surface therebetween, the first land portion is formed by a rib that is not provided with a lateral groove that completely crosses the first land portion in the tire axial direction, The first land portion includes a first sipe extending in the tire axial direction and a second sipe extending in the tire axial direction and adjacent to the first sipe in the tire circumferential direction, The first sipe includes a pair of first shallow bottom portions including both ends in the longitudinal direction, and a first deep bottom portion connecting the pair of first shallow bottom portions and having a depth greater than a depth of the pair of first shallow bottom portions, The second sipe includes a pair of second deep bottom portions including both ends in the longitudinal direction, and a second shallow bottom portion connecting the pair of second deep bottom portions and having a depth smaller than a depth of the pair of second deep bottom portions, The first deep bottom portion and the pair of second deep bottom portions are misaligned in the tire axial direction. tire. [Disclosure 2] The tire according to Disclosure 1, wherein one of the pair of first shallow portions in the tire axial direction overlaps with the other of the pair of second deep portions in the tire axial direction. [Disclosure 3] a plurality of first lateral grooves are formed in the first land portion, the first lateral grooves extending from the first circumferential edge and having ends that terminate within the first land portion; The tire according to Disclosure 1 or 2, wherein the first sipe extends from the interrupted end to the second circumferential edge. [Disclosure 4] the first transverse groove includes a first raised portion at the groove bottom, The tire according to Disclosure 3, wherein the first raised portion is not provided with a groove bottom sipe. [Disclosure 5] the pair of first shallow bottom portions include lateral groove-side first shallow bottom portions connected to the first lateral grooves, The tire according to Disclosure 3 or 4, wherein the length in the tire axial direction of the lateral groove-side first shallow bottom portion is 10% or more of the maximum thickness in the tire radial direction of the first land portion. [Disclosure 6] a plurality of second lateral grooves are formed in the first land portion, the second lateral grooves extending from the second circumferential edge and having ends that terminate within the first land portion; The tire according to any one of Disclosures 1 to 5, wherein the second sipe extends from the discontinuous end to the first circumferential edge. [Disclosure 7] the second transverse groove includes a second raised portion where the groove bottom is raised, The tire according to the present disclosure 6, wherein the second raised portion is provided with a groove bottom sipe that is connected to the second sipe. [Disclosure 8] The tire according to any one of Disclosures 1 to 7, wherein the first land portion is a crown land portion disposed closest to the tire equator. [Disclosure 9] The tire according to any one of Disclosures 1 to 8, wherein the depth of the first shallow portion and the depth of the second shallow portion are 10% to 50% of the maximum thickness of the first land portion in the tire radial direction. [Disclosure 10] The tire according to any one of Disclosures 1 to 9, wherein the depth of the first deep portion and the depth of the second deep portion are 70% to 90% of the maximum thickness of the first land portion in the tire radial direction. [Disclosure 11] The tire according to any one of Disclosures 1 to 10, wherein the width of the first sipes is smaller than the width of the second sipes. [Disclosure 12] the first circumferential edge and the second circumferential edge have a plurality of apexes that are convex toward an outer side of the first land portion, The tire according to any one of Disclosures 1 to 11, wherein, in a plan view of the tread, each of the plurality of apexes is formed by an arc having a curvature radius of 2 mm or more. [Disclosure 13] The tire described in the present disclosure 12, wherein each of the plurality of peaks is connected to either the first sipe or the second sipe. [Explanation of symbols]

[0072] 1 tire 3 1st Land Department 4 First sipe 5 Second sipe 6 First shallow section 7 1st deep bottom 8 2nd deep bottom 9 Second shallow section

Claims

1. A tire having a tread portion, the tread portion includes a first land portion including a first circumferential edge extending in the tire circumferential direction, a second circumferential edge extending in the tire circumferential direction, and a tread surface therebetween, the first land portion is formed by a rib that is not provided with a lateral groove that completely crosses the first land portion in the tire axial direction, the first land portion includes a first sipe extending in the tire axial direction and a second sipe extending in the tire axial direction and adjacent to the first sipe in the tire circumferential direction, The first sipe includes a pair of first shallow bottom portions including both ends in the longitudinal direction, and a first deep bottom portion connecting the pair of first shallow bottom portions and having a depth greater than a depth of the pair of first shallow bottom portions, The second sipe includes a pair of second deep bottom portions including both ends in the longitudinal direction, and a second shallow bottom portion connecting the pair of second deep bottom portions and having a depth smaller than a depth of the pair of second deep bottom portions, the first deep bottom portion and the pair of second deep bottom portions are misaligned in the tire axial direction, one of the pair of first shallow portions in the tire axial direction overlaps with the other of the pair of second deep portions in the tire axial direction; tire.

2. A tire having a tread portion, the tread portion includes a first land portion including a first circumferential edge extending in the tire circumferential direction, a second circumferential edge extending in the tire circumferential direction, and a tread surface therebetween, the first land portion is formed by a rib that is not provided with a lateral groove that completely crosses the first land portion in the tire axial direction, the first land portion includes a first sipe extending in the tire axial direction and a second sipe extending in the tire axial direction and adjacent to the first sipe in the tire circumferential direction, The first sipe includes a pair of first shallow bottom portions including both ends in the longitudinal direction, and a first deep bottom portion connecting the pair of first shallow bottom portions and having a depth greater than a depth of the pair of first shallow bottom portions, The second sipe includes a pair of second deep bottom portions including both ends in the longitudinal direction, and a second shallow bottom portion connecting the pair of second deep bottom portions and having a depth smaller than a depth of the pair of second deep bottom portions, the first deep bottom portion and the pair of second deep bottom portions are misaligned in the tire axial direction, a plurality of first lateral grooves are formed in the first land portion, the first lateral grooves extending from the first circumferential edge and having discontinuous ends within the first land portion; The first sipe extends from the interrupted end to the second circumferential edge. tire.

3. A tire having a tread portion, the tread portion includes a first land portion including a first circumferential edge extending in the tire circumferential direction, a second circumferential edge extending in the tire circumferential direction, and a tread surface therebetween, the first land portion is formed by a rib that is not provided with a lateral groove that completely crosses the first land portion in the tire axial direction, the first land portion includes a first sipe extending in the tire axial direction and a second sipe extending in the tire axial direction and adjacent to the first sipe in the tire circumferential direction, The first sipe includes a pair of first shallow bottom portions including both ends in the longitudinal direction, and a first deep bottom portion connecting the pair of first shallow bottom portions and having a depth greater than a depth of the pair of first shallow bottom portions, The second sipe includes a pair of second deep bottom portions including both ends in the longitudinal direction, and a second shallow bottom portion connecting the pair of second deep bottom portions and having a depth smaller than a depth of the pair of second deep bottom portions, the first deep bottom portion and the pair of second deep bottom portions are misaligned in the tire axial direction, a plurality of second lateral grooves are formed in the first land portion, the second lateral grooves extending from the second circumferential edge and having discontinuous ends within the first land portion; The second sipe extends from the interrupted end to the first circumferential edge. tire.

4. A tire having a tread portion, the tread portion includes a first land portion including a first circumferential edge extending in the tire circumferential direction, a second circumferential edge extending in the tire circumferential direction, and a tread surface therebetween, the first land portion is formed by a rib that is not provided with a lateral groove that completely crosses the first land portion in the tire axial direction, the first land portion includes a first sipe extending in the tire axial direction and a second sipe extending in the tire axial direction and adjacent to the first sipe in the tire circumferential direction, The first sipe includes a pair of first shallow bottom portions including both ends in the longitudinal direction, and a first deep bottom portion connecting the pair of first shallow bottom portions and having a depth greater than a depth of the pair of first shallow bottom portions, The second sipe includes a pair of second deep bottom portions including both ends in the longitudinal direction, and a second shallow bottom portion connecting the pair of second deep bottom portions and having a depth smaller than a depth of the pair of second deep bottom portions, the first deep bottom portion and the pair of second deep bottom portions are misaligned in the tire axial direction, the first circumferential edge and the second circumferential edge have a plurality of apexes that are convex toward an outer side of the first land portion, In a plan view of the tread, each of the plurality of peaks is formed by an arc having a curvature radius of 2 mm or more, Each of the plurality of apexes is connected to either the first sipe or the second sipe. tire.

5. The tire according to claim 2 , wherein one of the pair of first shallow portions in the tire axial direction overlaps with the other of the pair of second deep portions in the tire axial direction.

6. a plurality of first lateral grooves are formed in the first land portion, the first lateral grooves extending from the first circumferential edge and having discontinuous ends within the first land portion; The tire according to claim 1 , wherein the first sipe extends from the discontinued end of the first lateral groove to the second circumferential edge.

7. a plurality of second lateral grooves are formed in the first land portion, the second lateral grooves extending from the second circumferential edge and having discontinuous ends within the first land portion; The tire according to claim 1 , wherein the second sipe extends from the discontinued end of the second lateral groove to the first circumferential edge.

8. the first circumferential edge and the second circumferential edge have a plurality of apexes that are convex toward an outer side of the first land portion, The tire according to claim 1 , wherein, in a plan view of the tread, each of the plurality of apexes is formed by an arc having a curvature radius of 2 mm or more.

9. The tire according to claim 8 , wherein each of the plurality of apexes is connected to either the first sipe or the second sipe.

10. the first transverse groove includes a first raised portion at the groove bottom, The tire according to claim 2 or 6, wherein the first raised portion is not provided with a groove bottom sipe.

11. the pair of first shallow bottom portions includes a lateral groove-side first shallow bottom portion connected to the first lateral groove, The tire according to claim 2 , wherein the axial length of the lateral groove-side first shallow bottom portion is 10% or more of the maximum radial thickness of the first land portion.

12. the second lateral groove includes a second raised portion where the groove bottom is raised, The tire according to claim 3 or 7, wherein the second raised portion is provided with a groove bottom sipe that is connected to the second sipe.

13. The tire according to claim 1 , wherein the first land portion is a crown land portion disposed closest to the tire equator.

14. The tire according to any one of claims 1 to 13, wherein a depth of the first shallow portion and a depth of the second shallow portion are 10% to 50% of a maximum thickness of the first land portion in the tire radial direction.

15. The tire according to any one of claims 1 to 14, wherein a depth of the first deep portion and a depth of the second deep portion are 70% to 90% of a maximum thickness of the first land portion in the tire radial direction.

16. 16. The tire according to claim 1, wherein a width of the first sipes is smaller than a width of the second sipes.

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