Pneumatic tire

Abstract

Provided is a pneumatic tire that can suppress the occurrence of a slip phenomenon even when traveling at high speed under various road surface conditions and improve steering stability under wet and slippery conditions. A tread (5) includes: shoulder main grooves (20) that extend obliquely to a land portion (90) side in a vehicle body width direction inside as they go from a front ground contact side to a rear ground contact side in the tire rotation direction, long dimension portions (21) and short dimension portions (22) having different oblique angles alternately and continuously extending in the tire circumferential direction; and a shoulder land portion (70) disposed inside the shoulder main grooves (20) in the vehicle body width direction, the shoulder land portion (70) having: first oblique grooves (31) that continuously extend to the land portion (90) side from the short dimension portions (22) and obliquely go to the rear ground contact side as they go toward the land portion (90); and second oblique grooves (32) that extend to the land portion (90) side from the long dimension portions (21) and obliquely go to the rear ground contact side as they go toward the land portion (90).

Description

Technical Field

[0001] This invention relates to a pneumatic tire. Background Technology

[0002] Previously, tires with a specified direction of rotation were known. Patent Document 1 discloses a tire with inclined grooves that are continuous with each other via the shoulder main grooves in the middle land portion between the crown main groove and the shoulder main groove in the tread width direction, and in the shoulder land portion further outward in the tread width direction than the shoulder main groove. These inclined grooves are grooves that slope towards the rear contact side (the side opposite to the tire's rotation direction) in the tire's rotation direction as they move outward in the tread width direction, including a middle lateral groove in the middle land portion and a shoulder lateral groove in the shoulder land portion, thereby achieving high water drainage performance.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-142785 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Even with conventional tires, there are concerns about slippage due to insufficient drainage when driving in wet conditions, such as in deep puddles or at high speeds. There is room for improvement in this regard.

[0008] Therefore, the purpose of this invention is to provide a pneumatic tire that can suppress slippage even under various road conditions and at high speeds, thereby improving handling stability in wet conditions.

[0009] Methods for solving problems

[0010] The pneumatic tire of the present invention has a tread including a contact end relative to the road surface, and the direction of rotation is specified, wherein the tread includes: a shoulder main groove that extends obliquely toward the contact end side in the vehicle width direction from the front contact side toward the rear contact side as the tire rotates, and long and short portions with different inclination angles extend alternately and continuously along the tire circumferential direction; and a shoulder land portion disposed in the vehicle width direction of the shoulder main groove, the shoulder land portion having: a first inclined groove that extends continuously toward the contact end side along with the short portion and is inclined toward the rear contact side toward the contact end; and a second inclined groove that extends from the long portion toward the contact end side and is inclined toward the rear contact side toward the contact end.

[0011] Invention Effects

[0012] According to the present invention, a pneumatic tire can be provided that can suppress slippage even under various road conditions and at high speeds, thereby improving handling stability in wet conditions. Attached Figure Description

[0013] Figure 1 This is a diagram showing the tread pattern of an inflatable tire according to an embodiment.

[0014] Figure 2 yes Figure 1 An enlarged view of the portion shown in section II.

[0015] Figure 3 yes Figure 1 An enlarged view of part III.

[0016] Explanation of reference numerals in the attached figures:

[0017] 1. Tires (pneumatic tires)

[0018] 5. Tread

[0019] 10 Central Main Channel

[0020] 20 Tire shoulder main groove

[0021] 21 Long dimension section

[0022] 22 Short Size Section

[0023] 31 First Inclined Groove

[0024] 32 Second Inclined Groove

[0025] 33 Branch slots

[0026] 70 Tire shoulder land

[0027] 90 Grounding terminal

[0028] C1 Front landing side

[0029] C2 Rear Landing Side

[0030] S1 Tire Equator

[0031] W (tread width direction)

[0032] W1 refers to the inner side of the vehicle body in the width direction. Detailed Implementation

[0033] The embodiments will now be described with reference to the accompanying drawings. Figure 1 This is a planar view of a portion of the tread 5 of tire 1, which is an embodiment of a pneumatic tire. Figure 1 The image shows the tread pattern 6 provided on the tread surface 5a, which serves as the surface of the tread 5. Figure 2 yes Figure 1 An enlarged view of the portion shown in section II. Figure 3 yes Figure 1 An enlarged view of part III.

[0034] The tire 1 in the embodiment including the tread 5 described above is a tire with a specified direction of rotation, for example, suitable as a rain tire for racing cars traveling at high speeds. It should be noted that the structure of the tire 1 in the embodiment is not limited to this rain tire, and can be used as a pneumatic tire for various other vehicles.

[0035] exist Figures 1-3 In the diagram, arrow W represents the tread width direction parallel to the rotation axis of tire 1, W1 represents the inner side of the vehicle body width direction when tire 1 is mounted on the vehicle, and W2 represents the outer side of the vehicle body width direction. The tread width direction is also the left-right direction of tread 5, with W1 and W2 both representing the outer side of the tread width direction. Furthermore, in... Figures 1-3 In the diagram, arrow C represents the tire's circumferential direction, C1 represents one side of the tire's circumferential direction, and C2 represents the other side of the tire's circumferential direction. Here, arrow C1 indicates the rotation direction specified by tire 1. C1 is the front contact side that first contacts the road surface when the tire rotates, and C2 is the rear contact side that last contacts the road surface when the tire rotates.

[0036] exist Figures 1-3 The image shows the tire equator S1. The tire equator S1 is an imaginary line extending circumferentially along the tire surface 5a, at the center of the tread width. Figure 1 and Figure 3 The image shows the ends of the tire tread surface 5a in the width direction that are in contact with the road surface, namely the grounding terminals 90.

[0037] The tread pattern 6 in this embodiment is a symmetrical pattern with the tire equator S1 as the line of symmetry. Hereinafter, the tread pattern 6 of the tread 5 in this embodiment will be described.

[0038] like Figure 1 As shown, the tread pattern 6 includes a pair of central main grooves 10, a central land area 50, a pair of shoulder main grooves 20, a pair of middle land areas 60, and a pair of shoulder land areas 70.

[0039] A pair of central main grooves 10 are respectively positioned on both sides of the tire equator S1 in the tread width direction, between the tire equator S1 and the shoulder main groove 20. The central main groove 10 is a groove extending in a straight line along the tire circumference. The width and depth of the central main groove 10 are, for example, a width of 10mm or more and approximately 20mm less, and a depth of 4mm or more and approximately 8mm less, but are not limited to these. It should be noted that the central main groove 10 is not limited to a straight line; for example, it can also be a serrated shape along the tire circumference.

[0040] A central land section 50 is formed between a pair of central main grooves 10. The central land section 50 is formed as a rib extending along the circumference of the tire. The tire equator S1 passes approximately in the center of the width direction of the central land section 50. The width of the central land section 50 is, for example, about 15 mm or more and about 40 mm or less, but is not limited to this.

[0041] The central landmass 50 has multiple notches 15. For example... Figure 2 As shown, for multiple notches 15, a pair of left and right notches 15 positioned approximately at the same location along the tire circumference are grouped together, and multiple groups of pairs of notches 15 are arranged at approximately equal intervals along the tire circumference. Each pair of left and right notches 15 is connected to a pair of left and right central main grooves 10. Each notch 15 moves forward from the central main groove 10 toward the tire equator S1 towards the ground side (in... Figure 1 as well as Figure 2 It extends obliquely (towards the lower side) and forms an end near the front of the tire equator S1, and closes within the central land section 50.

[0042] like Figure 2 As shown, the notch 15 on the tire surface has a tapering shape where the width decreases as it moves from the opening communicating with the central main groove 10 toward the end. The notch 15 also has a groove shape where the depth decreases as it moves from the opening communicating with the central main groove 10 toward the end. The width and depth of the notch 15 are, for example, a maximum width of approximately 2 mm and 6 mm or less, a minimum width of approximately 0.5 mm and 3 mm or less, and a maximum depth of approximately 4 mm and 8 mm or less, but are not limited thereto. The inclination angle θ1 of the notch 15 relative to the tire circumference is, for example, approximately 20° and 90° or less, but is not limited thereto.

[0043] like Figure 1 and Figure 2As shown, the central land section 50 has a plurality of central sipes 80. Each central sipe 80 is arranged at approximately equal intervals along the tire circumference at a position that does not overlap with the pair of left and right recesses 15 in the tire circumference direction. The central sipe 80 is a narrow groove extending along the width direction of the tread, traversing the central land section 50 in the width direction, and communicating with the central main grooves 10 on both sides of the central land section 50. The width of the central sipe 80 is, for example, about 0.5 mm or more and less than 2 mm, but is not limited to this.

[0044] The central sipe 80 of the embodiment has a plurality of first central sipes 80A and a plurality of second central sipes 80B. The first central sipes 80A and the second central sipes 80B are alternately arranged in the tire circumferential direction. The tire circumferential distance between the first central sipes 80A and the second central sipes 80B, that is, the tire circumferential distance P1 between adjacent central sipes 80 in the tire circumferential direction, is, for example, more than 10 mm and less than 30 mm, but is not limited to this. It should be noted that the distance P1 mentioned here refers to the distance between the centers in the width direction of each adjacent central sipe 80 in the tire circumferential direction. The same applies to the distances P2, P3, and P4 described later.

[0045] The widths of the first central cutting groove 80A and the second central cutting groove 80B can, for example, be approximately 1 mm. However, in this embodiment, it is preferable that the depth of the first central cutting groove 80A is deeper than the depth of the second central cutting groove 80B. For example, the depth of the first central cutting groove 80A is 50% or more and 100% or less relative to the depth of the central main groove 10, preferably 60% or more and 80% or less. For example, the depth of the second central cutting groove 80B is 10% or more and 25% or less relative to the depth of the central main groove 10. More specifically, for example, the depth of the first central cutting groove 80A is approximately 2 mm or more and 8 mm or less, preferably 2.4 mm or more and 6.4 mm or less, and the depth of the second central cutting groove 80B is approximately 0.4 mm or more and 2 mm or less. Figure 2 As shown, between a pair of adjacent left and right recesses 15 in the tire circumferential direction, the deeper first central groove 80A is positioned on the forward contact side (C1) of the shallower second central groove 80B. This facilitates obtaining an optimal contact shape relative to the road surface, and as the rigidity of the central land portion 50 decreases, heat generation increases, ensuring grip performance.

[0046] like Figure 1 As shown, the left and right pair of tire shoulder main grooves 20 are respectively positioned on the inner side and the outer side of the left and right pair of central main grooves 10 in the vehicle width direction. Figure 3 The image shows a portion of the tire shoulder main groove 20 located on the inner side of the central main groove 10 on the left side, in the vehicle body width direction. It should be noted that... Figure 3The structure of the tire shoulder main groove 20 shown is also common to the tire shoulder main groove 20 located on the outer side in the width direction of the vehicle body, so its description is omitted.

[0047] like Figure 3 As shown, the main shoulder groove 20 has multiple long sections 21 and multiple short sections 22 that are shorter than the long sections 21. These long sections 21 and short sections 22 are arranged in an alternating and continuous manner in the tire circumferential direction.

[0048] like Figure 3 As shown, the longer portion 21 extends from the front landing side to the rear landing side ( Figure 3 The shorter portion 22 extends obliquely towards the grounding end 90° in the width direction of the vehicle body, from the lower side to the upper side. The shorter portion 22 extends from the front end of the front grounding side of the longer portion 21 towards the rear grounding side. Figure 3 The tire shoulder main groove 20 extends obliquely towards the contact end 90° in the width direction of the vehicle body (from the bottom to the top). The long portion 21 and the short portion 22 have different inclination angles relative to the tire circumference from the front contact side to the rear contact side, with the inclination angle of the long portion 21 being smaller than that of the short portion 22. For example, the inclination angle θ2 of the long portion 21 relative to the tire circumference is 10° or more and 60° or less, and the inclination angle θ3 of the short portion 22 relative to the tire circumference is 40° or more and 90° or less, but it is not limited to these. The long portion 21 and the short portion 22, with different inclination angles, extend alternately and continuously in a serrated pattern along the tire circumference. The portion where the front contact side ends of the long portion 21 and the short portion 22 intersect face the rear contact side and are formed in a V-shape on the tire equator side. The aforementioned pair of left and right notches 15 are configured in two sets for each long dimension portion 21, that is, each long dimension portion 21 with a spacing of two sets of left and right pairs of notches 15 is configured.

[0049] The width and depth of the long portion 21 and the short portion 22 of the main shoulder groove 20 can be the same, for example, the width is more than 5 mm and less than 20 mm, and the depth is more than 3 mm and less than 8 mm, but it is not limited to this.

[0050] like Figure 1 As shown, a pair of left and right intermediate land portions 60 are respectively formed between a pair of left and right central main grooves 10 and a pair of left and right shoulder main grooves 20. The intermediate land portions 60 are formed as ribs extending along the tire circumference.

[0051] like Figure 3As shown, each intermediate land portion 60 has a plurality of intermediate sipes 81 extending along the tread width direction and arranged at approximately equal intervals in the tire circumferential direction. The intermediate sipes 81 are arranged at approximately equal intervals in the tire circumferential direction. Each intermediate sipe 81 is a narrow groove extending along the tread width direction, traversing the intermediate land portion 60 in the width direction, and communicating with the central main grooves 10 on both sides of the intermediate land portion 60 and the shoulder main grooves 20. The circumferential interval P2 between adjacent intermediate sipes 81 is smaller than the circumferential interval P1 between the plurality of central sipes 80. The circumferential interval P2 of the intermediate sipes 81 is, for example, 10 mm or more and 20 mm or less, but is not limited to this.

[0052] like Figure 1 As shown, the left and right shoulder land portions 70 are formed on the outer side of the left and right shoulder main grooves 20 in the tread width direction. Figure 3 The image shows a portion of the tire shoulder land portion 70 located on the inner side of the central main slot 10 on the left side in the vehicle width direction. It should be noted that... Figure 3 The structure of the tire shoulder land portion 70 shown is also common to the tire shoulder land portion 70 located on the outer side in the width direction of the vehicle body, therefore, its description is omitted.

[0053] like Figure 3 As shown, the shoulder land portion 70 includes a plurality of inclined grooves 30 extending from the main shoulder groove 20 toward the ground contact end 90 and a plurality of shoulder tread blocks 73 arranged in the tire circumferential direction.

[0054] The plurality of inclined grooves 30 have a plurality of first inclined grooves 31 and a plurality of second inclined grooves 32. The first inclined grooves 31 and the second inclined grooves 32 are arranged alternately at approximately the same interval in the tire circumferential direction.

[0055] The first inclined groove 31 extends continuously toward the contact end 90 from the short-length portion 22 of the main shoulder groove 20, and slopes toward the rearward contact end 90. Furthermore, the first inclined groove 31 has a curved portion 31a that protrudes at an obtuse angle toward the rearward contact end. Thus, the first inclined groove 31 has: the aforementioned curved portion 31a; a continuous portion 31b, which is closer to the short-length portion 22 than the curved portion 31a and continuous with the short-length portion 22; and a front end portion 31c, which is closer to the contact end 90 than the curved portion 31a and shorter than the continuous portion 31b. The continuous portion 31b exists on the extension line of the short-length portion 22 and extends linearly along the extension direction of the short-length portion 22. The front end portion 31c passes through the contact end 90 and extends further outward in the tread width direction than the contact end 90. The angle θ4 of the curved portion 31a is, for example, about 120° or more and 170° or less, but is not limited to this. The first inclined groove 31 has a curved portion 31a, which is curved in such a way that the angle of inclination relative to the tread width direction decreases near the ground end 90. The notch 15 is inclined approximately along the short-length portion 22 of the main shoulder groove 20 and the continuous portion 31b of the first inclined groove 31.

[0056] The second inclined groove 32 extends from the long portion 21 of the main shoulder groove 20 toward the ground contact end 90, and slopes backward toward the ground contact end 90. The second inclined groove 32 extends in a straight line toward the ground contact end 90, starting from the middle of the long portion 21 and close to the first inclined groove 31. The second inclined groove 32 passes through the ground contact end 90 and extends further outward in the tread width direction than the ground contact end 90.

[0057] Preferably, the inclination angle θ5 of the front end 31c of the first inclined groove 31 relative to the tread width direction is approximately the same as the inclination angle θ6 of the second inclined groove 32 relative to the tread width direction. That is, preferably, near the ground contact end 90, the inclination angles of the first inclined groove 31 and the second inclined groove 32 relative to the tread width direction are approximately the same. These inclination angles θ5 and θ6 are, for example, about 5° and less than 45°, but are not limited to this. The first inclined groove 31 and the second inclined groove 32 help improve drainage performance, but if the inclination angles θ5 and θ6 are less than 5°, the drainage performance is reduced, especially at areas where water accumulates; therefore, the above-mentioned range is preferred.

[0058] The shoulder land portion 70 also has a plurality of branch grooves 33. The branch grooves 33 branch from each of the second inclined grooves 32 toward the first inclined groove 31 on the front contact side, and slope toward the tire equator S1 as they approach the first inclined groove 31, forming an end near the first inclined groove 31 and closing within the shoulder land portion 70. The branch grooves 33 may have a tapered shape on the end side, and the groove depth on the end side gradually decreases towards the end.

[0059] The width and depth of the first inclined groove 31, the second inclined groove 32 and the branch groove 33 can be equal, for example, the width is more than 5 mm and less than 20 mm, and the depth is more than 3 mm and less than 8 mm, but it is not limited to this.

[0060] like Figure 1 and Figure 3 As shown, the plurality of shoulder tread blocks 73 arranged along the tire circumference are tire tread blocks divided within the shoulder land portion 70 by the shoulder main groove 20 and the inclined groove 30. The shoulder tread block 73 of the embodiment has a first shoulder tread block 71 and a second shoulder tread block 72.

[0061] The first shoulder tread block 71 is divided by a portion of the main shoulder groove 20, a first inclined groove 31, and a second inclined groove 32 adjacent to the first inclined groove 31 on the rear contact side. A branch groove 33 is included in the first shoulder tread block 71.

[0062] The second shoulder tread block 72 is divided by a portion of the main shoulder groove 20, a first inclined groove 31, and a second inclined groove 32 adjacent to the first inclined groove 31 on the front contact side.

[0063] The shoulder tread block 73 has a plurality of shoulder grooves 82 extending in a direction intersecting the tire circumference and arranged at approximately equal intervals in the tire circumference.

[0064] like Figure 3 As shown, the plurality of tire shoulder grooves 82 have a plurality of first tire shoulder grooves 82a disposed on the first tire shoulder tread block 71 and a plurality of second tire shoulder grooves 82b disposed on the second tire shoulder tread block 72.

[0065] A plurality of first shoulder sipes 82a, provided on the first shoulder tread block 71, extend along the width direction of the tread. They traverse the first shoulder tread block 71 in the width direction and communicate with the elongated portion 21 of the main shoulder groove 20, as well as any one of the first inclined groove 31 and the branch groove 33. The circumferential spacing P3 between adjacent first shoulder sipes 82a is smaller than the circumferential spacing P1 between the plurality of central grooves 80. The circumferential spacing P3 of the first shoulder sipes 82a is, for example, 10 mm or more and 20 mm or less, but is not limited to this.

[0066] The plurality of second shoulder sipes 82b provided on the second shoulder tread block 72 are inclined toward the rearward contact side as they face the contact end 90. Each second shoulder sipe extends substantially parallel to the front end 31c of the first inclined groove 31 and the second inclined groove 32. That is, the second shoulder sipe 82b extends along at least a portion of the inclined groove 30.

[0067] The inner side of the second shoulder sipe 82b in the tread width direction (in) Figure 3The end of the second shoulder groove 82b (located on the right side) is connected to either the long portion 21 of the main shoulder groove 20 or the continuous portion 31b of the first inclined groove 31. The circumferential spacing P4 of the adjacent second shoulder grooves 82b in the tire circumferential direction is less than the circumferential spacing P1 of the plurality of central grooves 80. The circumferential spacing P4 of the second shoulder grooves 82b in the tire circumferential direction is, for example, more than 5 mm and less than 20 mm, but is not limited to this.

[0068] like Figure 3 As shown, the first shoulder tread block 71 is also provided with a U-shaped sipe 83 having a generally U-shaped shape. The U-shaped sipe 83 is disposed between the front end 31c of the first inclined groove 31 and the second inclined groove 32 adjacent to the first inclined groove 31 on the rear contact side, and passes through the contact end 90. The two ends of the U-shaped sipe 83 are disposed on the open side that separates in the tire circumferential direction on the outer side in the tread width direction, and are generally arranged parallel to the front end 31c of the first inclined groove 31 and the second inclined groove 32.

[0069] The width and depth of the intermediate sipe 81 located on the intermediate land portion 60, the shoulder sipe 82 (first shoulder sipe 82a, second shoulder sipe 82b) located on the shoulder land portion 70, and the U-shaped sipe 83 are, for example, approximately 0.5 mm or more and 2 mm or less in width, and approximately 0.4 mm or more and 2 mm or less in depth, but are not limited thereto. The width and depth of these sipes can all be the same, or at least one can be different, or all of them can be different.

[0070] In the tire 1 of the embodiment, the area ratio of each groove and each sipe relative to the entire surface of the tire 1, i.e., the void ratio, is preferably 50% or less.

[0071] The tire 1 according to the embodiment having the above structure achieves the following effects.

[0072] (1) The tire 1 of the embodiment has a tread 5 including a ground contact end 90 relative to the road surface, and the rotation direction is specified. The tread 5 includes: a shoulder main groove 20, which extends obliquely toward the ground contact end 90 in the vehicle width direction from the front ground contact side toward the rear ground contact side when the tire rotates, with long-length portions 21 and short-length portions 22 of different inclination angles extending alternately and continuously in the tire circumferential direction; and a shoulder land portion 70, which is disposed in the vehicle width direction of the shoulder main groove 20. The shoulder land portion 70 has: a first inclined groove 31, which extends continuously toward the ground contact end 90 with the short-length portion 22 and is inclined toward the rear ground contact side toward the ground contact end 90; and a second inclined groove 32, which extends from the long-length portion 21 toward the ground contact end 90 and is inclined toward the rear ground contact side toward the ground contact end 90.

[0073] In vehicles, there are cases where the fitted tires are given a camber angle. When the camber angle is negative, the contact pressure on the inner side of the tire tread in the vehicle width direction is higher than that on the outer side, making it more susceptible to road conditions. Here, when the tire 1 of the embodiment is given a negative camber angle and is driven on a wet road surface, the main shoulder groove 20, the first inclined groove 31, and the second inclined groove 32 provided on the inner side of the tire tread in the vehicle width direction generate a squeezing effect that removes water from the front contact side to the rear contact side, i.e., the rear of the vehicle, thus achieving high drainage performance. For example, even when the water on the road surface is deep or when driving at high speed, the tire 1 of the embodiment can still generate the aforementioned squeezing effect, thereby suppressing slippage. Therefore, according to the tire 1 of the embodiment, even under various road conditions and at high speeds, slippage can be suppressed, thereby improving handling stability in wet conditions.

[0074] (2) In the tire 1 of the above (1) embodiment, the first inclined groove 31 is bent in such a way that the inclination angle relative to the tread width direction becomes smaller near the ground end 90. Near the ground end 90, the inclination angles of the first inclined groove 31 and the second inclined groove 32 relative to the tread width direction are approximately the same. The first inclined groove 31 and the second inclined groove 32 are arranged at approximately the same interval in the tire circumferential direction.

[0075] As a result, the flow of water from near the contact end 90 to the outer side of the tread 5 based on the first inclined groove 31 and the second inclined groove 32 becomes smoother, and the drainage performance brought about by the wiping action is further improved. As a result, it is possible to suppress slippage at high speeds and improve handling stability in wet conditions.

[0076] (3) In the tire 1 of the above (1) and (2) embodiments, the shoulder land portion 70 has a branch groove 33 that branches from the second inclined groove 32 toward the front grounding side and is closed in the shoulder land portion 70.

[0077] As a result, the rigidity of the tire shoulder land 70 is moderately reduced, making it easier to move and thus increasing its heat generation. By increasing its heat generation, the grip performance of the tire shoulder land 70 is improved even in wet conditions. The increased area of ​​the branch grooves 33 further suppresses slippage in deeper water.

[0078] (4) In the tire 1 of the above (1) to (3) embodiments, the tread 5 includes a central main groove 10 extending along the tire circumferential direction between the tire equator S1 and the main groove 20 of the shoulder.

[0079] This improves straight-line stability and ensures drainage.

[0080] It should be noted that the present invention is not limited to the above-described embodiments. Modifications and improvements made within the scope of achieving the purpose of the present invention are also included within the scope of the present invention.

[0081]

[0082] <a-1>

[0083] A pneumatic tire having a tread including a contact end relative to the road surface, and a specified direction of rotation, wherein...

[0084] The tread includes:

[0085] The tire shoulder main groove extends obliquely towards the contact patch end on the vehicle width side of the tread, from the front contact patch towards the rear contact patch as the tire rotates, with long and short portions of different angles extending continuously and alternately along the tire circumferential direction; and

[0086] The tire shoulder portion is located inside the main tire shoulder groove in the vehicle body width direction.

[0087] The shoulder land portion has:

[0088] A first inclined groove, which extends continuously toward the grounding end along with the short-length portion, and slopes toward the rear-landing side as it approaches the grounding end; and

[0089] The second inclined groove extends from the long portion toward the grounding end side and tilts toward the rear grounding side as it moves toward the grounding end.

[0090] <a-2>

[0091] according to <a-1>The pneumatic tire, wherein,

[0092] The first inclined groove bends near the grounding end in a manner that decreases in the angle of inclination relative to the tread width direction.

[0093] Near the grounding end, the first and second inclined grooves have approximately the same inclination angle relative to the tread width direction.

[0094] The first inclined groove and the second inclined groove are arranged at approximately the same intervals along the tire circumference.

[0095] <a-3>

[0096] according to <a-1>or <a-2>The pneumatic tire, wherein,

[0097] The tire shoulder land has a branching groove that branches from the second inclined groove toward the front contact side and is closed within the tire shoulder land.

[0098] <a-4>

[0099] according to <a-1>or <a-2>The pneumatic tire, wherein,

[0100] The tread includes a central main groove extending circumferentially between the tire equator and the main shoulder groove.

[0101] Furthermore, the present invention includes the following The aforementioned pneumatic tire.

[0102]

[0103] Conventionally, tires with a specified direction of rotation are known. One example of such a tire is one with a crown land portion (central land portion) extending circumferentially between a pair of main crown grooves at the center of the tread width direction, and inclined grooves on both sides of this crown land portion in the tread width direction. These inclined grooves are grooves that slope towards the rear contact side (the side opposite to the tire's rotation direction) in the tire's rotation direction as they move outwards in the tread width direction, including a central lateral groove in the central land portion and a shoulder lateral groove in the shoulder land portion, thereby achieving high water drainage. In such tires, ensuring the grip performance of the central land portion tends to improve handling stability, but the grip performance of the central land portion tends to decrease when driving in wet conditions. This tendency becomes significant, for example, at high speeds and when the ground contact pressure decreases due to vehicle weight reduction, thus leaving room for improvement. Therefore, the object of the present invention is to provide a pneumatic tire that, particularly when driving in wet conditions, ensures the grip performance of the central land portion, thereby improving handling stability. Pneumatic tires include the following combinations.

[0104] <b-1>

[0105] A pneumatic tire having a tread including a contact end relative to the road surface, and a specified direction of rotation, wherein...

[0106] The tread includes:

[0107] A pair of central main grooves are positioned on either side of the tire equator and extend circumferentially along the tire; and

[0108] The central land section is positioned between the pair of central main slots and extends circumferentially along the tire.

[0109] The central land section has a pair of recesses that communicate with and are closed within the pair of central main grooves, and the tires are positioned approximately at the same location circumferentially.

[0110] The notch extends obliquely from the central main groove toward the tire equator toward the front contact side with the road surface during tire rotation.

[0111] Multiple sets of pairs of the notches are arranged at intervals in the circumferential direction of the tire.

[0112] <b-2>

[0113] according to <b-1>The pneumatic tire, wherein,

[0114] The central land portion has a plurality of central sipes that extend along the tread width direction and are spaced apart in the tire circumferential direction at a position that does not overlap with the pair of notches.

[0115] <b-3>

[0116] according to <b-2>The pneumatic tire, wherein,

[0117] The central sipe has a plurality of first central sipes and a plurality of second central sipes arranged alternately in the tire circumferential direction.

[0118] The depth of the first central groove is greater than the depth of the second central groove.

[0119] <b-4>

[0120] according to <b-3>The pneumatic tire, wherein,

[0121] The depth of the first central groove is more than 50% and less than 100% of the depth of the central main groove.

[0122] The depth of the second central groove is more than 10% and less than 25% of the depth of the central main groove.

[0123] <b-5>

[0124] according to <b-2>or <b-3>The pneumatic tire, wherein,

[0125] The tread includes:

[0126] The tire shoulder main groove is positioned inside the vehicle width direction compared to the central main groove; and

[0127] The intermediate land section is located between the central main groove and the shoulder main groove.

[0128] The intermediate land portion has a plurality of intermediate sipes that extend along the tread width direction and are spaced apart in the tire circumferential direction.

[0129] The tire circumferential spacing of the plurality of intermediate sipes is smaller than the tire circumferential spacing of the central sipe.

[0130] <b-6>

[0131] according to <b-5>The pneumatic tire, wherein,

[0132] The tread includes:

[0133] An inclined groove extending from the main shoulder groove toward the ground contact end, and inclined from the front ground contact side toward the rear ground contact side as it approaches the ground contact end; and

[0134] The tire shoulder tread blocks are divided by the main shoulder groove and the inclined groove.

[0135] The tire shoulder tread blocks have shoulder grooves that extend in a direction intersecting the tire circumferential direction and are spaced apart in the tire circumferential direction.

[0136] The circumferential spacing of the shoulder sipes is smaller than the circumferential spacing of the central sipes.

[0137] <b-7>

[0138] according to <b-6>The pneumatic tire, wherein,

[0139] The shoulder groove has a shoulder groove that runs through the ground end and extends along at least a portion of the inclined groove.

[0140] According to the above Pneumatic tires provide improved handling stability, especially when driving in slippery conditions, by ensuring grip on the central land area.

Claims

1. A pneumatic tire having a tread including a contact end relative to the road surface, and a specified direction of rotation, wherein, The tread includes: The tire shoulder main groove extends obliquely towards the contact patch end on the vehicle width side of the tread, from the front contact patch towards the rear contact patch as the tire rotates, with long and short portions of different angles extending continuously and alternately along the tire circumferential direction; and The tire shoulder portion is located inside the main tire shoulder groove in the vehicle body width direction. The shoulder land portion has: A first inclined groove, which extends continuously toward the grounding end along with the short-length portion, and slopes toward the rear-landing side as it approaches the grounding end; and The second inclined groove extends from the long portion toward the grounding end side and tilts toward the rear grounding side as it moves toward the grounding end.

2. The pneumatic tire according to claim 1, wherein, The first inclined groove is curved such that the angle of inclination relative to the tread width direction decreases near the grounding end. Near the grounding end, the first and second inclined grooves have approximately the same inclination angle relative to the tread width direction. The first and second inclined grooves are arranged at approximately the same intervals in the tire circumferential direction.

3. The pneumatic tire according to claim 1 or 2, wherein, The tire shoulder land has a branching groove that branches from the second inclined groove toward the front contact side and is closed within the tire shoulder land.

4. The pneumatic tire according to claim 1 or 2, wherein, The tread includes a central main groove extending circumferentially between the tire equator and the main shoulder groove.

5. The pneumatic tire according to claim 1, wherein, The tread includes: A pair of central main grooves are positioned on either side of the tire equator and extend circumferentially along the tire; and The central land section is positioned between the pair of central main slots and extends circumferentially along the tire. The central land section has a pair of recesses that communicate with and are closed within the pair of central main grooves, and the tires are positioned approximately at the same location circumferentially. The notch extends obliquely from the central main groove toward the tire equator toward the front contact side with the road surface during tire rotation. Multiple sets of pairs of the notches are arranged at intervals in the circumferential direction of the tire.

6. The pneumatic tire according to claim 5, wherein, The central land portion has a plurality of central sipes that extend along the tread width direction and are spaced apart in the tire circumferential direction at a position that does not overlap with the pair of notches.

7. The pneumatic tire according to claim 6, wherein, The central sipe has a plurality of first central sipes and a plurality of second central sipes arranged alternately in the tire circumferential direction. The depth of the first central groove is greater than the depth of the second central groove.

8. The pneumatic tire according to claim 7, wherein, The depth of the first central groove is more than 50% and less than 100% of the depth of the central main groove. The depth of the second central groove is more than 10% and less than 25% of the depth of the central main groove.

9. The pneumatic tire according to any one of claims 6 to 8, wherein, The tread includes: The tire shoulder main groove is positioned inside the vehicle width direction compared to the central main groove; and The intermediate land section is located between the central main groove and the shoulder main groove. The intermediate land portion has a plurality of intermediate sipes that extend along the tread width direction and are spaced apart in the tire circumferential direction. The tire circumferential spacing of the plurality of intermediate sipes is smaller than the tire circumferential spacing of the central sipe.

10. The pneumatic tire according to any one of claims 6 to 8, wherein, The tread includes: An inclined groove extending from the main shoulder groove toward the ground contact end, and inclined from the front ground contact side toward the rear ground contact side as it approaches the ground contact end; and The tire shoulder tread blocks are divided by the main shoulder groove and the inclined groove. The tire shoulder tread blocks have shoulder grooves that extend in a direction intersecting the tire circumferential direction and are spaced apart in the tire circumferential direction. The circumferential spacing of the shoulder sipes is smaller than the circumferential spacing of the central sipes.

11. The pneumatic tire according to claim 10, wherein, The shoulder groove has a shoulder groove that runs through the ground end and extends along at least a portion of the inclined groove.

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