Pneumatic tires

Abstract

To provide a pneumatic tire enabling the ground contact area thereof to be enlarged even when tire internal pressure is set to be low.SOLUTION: A pneumatic tire according to the embodiment comprises: two major grooves 12 provided in a tread 10 and extending in a tire circumferential direction CD; a center land portion 14 formed between the two major grooves 12 and extending in the tire circumferential direction CD; a pair of shoulder land portions 16 formed between ground contact ends E and the major grooves 12; a center sub groove 18 which has groove width narrower than that of the major groove 12 and which is provided in the center land portion 14 extending in the tire circumferential direction CD; and shoulder sub grooves 20 which have groove widths narrower than those of the major grooves 12 and are provided in the shoulder land portions 16 extending in the tire circumferential direction CD.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Pneumatic tires used in competitions such as drag racing often have a small groove area in the tread, known as the void ratio, in order to increase the contact area and provide better grip and traction.

[0003] Such pneumatic tires may have their internal tire pressure set low in order to increase the contact area even when used in a competition (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2005-306155 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the internal tire pressure is set low in a pneumatic tire with a small void ratio, there are likely to be localized areas in the tire width direction that are difficult to contact with the ground, and there is a risk that a sufficient contact area cannot be obtained.

[0006] In view of the above circumstances, an object of the present invention is to provide a pneumatic tire that can increase the ground contact area even when the tire internal pressure is set low. [Means for solving the problem]

[0007] A pneumatic tire according to an embodiment of the present invention includes two main grooves provided in a tread and extending in a tire circumferential direction, a center land portion formed between the two main grooves and extending in the tire circumferential direction, a pair of shoulder land portions formed between a ground contact edge and the main grooves, a center sub-groove provided in the center land portion, which has a groove width narrower than that of the main grooves and extends in the tire circumferential direction, and a shoulder sub-groove provided in the shoulder land portion, which has a groove width narrower than that of the main grooves and extends in the tire circumferential direction, the center sub-groove is straight and extends parallel to the tire circumferential direction, and the groove center line of the main groove is aligned with the ground contact edge. a first main groove central inclined portion extending at an incline toward one side in the tire width direction with respect to the tire circumferential direction, and a second main groove central inclined portion extending at an incline toward the tire circumferential direction in the opposite direction to the first main groove central inclined portion with respect to the tire circumferential direction and shorter than the first main groove central inclined portion; a groove center line of the shoulder sub-groove extending in a zigzag manner in the tire circumferential direction, and a second sub-groove central inclined portion extending at an incline toward one side in the tire width direction with respect to the tire circumferential direction, and shorter than the first sub-groove central inclined portion; At least a portion of the first sub groove central inclined portion faces the first main groove central inclined portion in the tire width direction, and at least a portion of the second sub groove central inclined portion faces the second main groove central inclined portion in the tire width direction, and at a position where the first sub groove central inclined portion faces the first main groove central inclined portion in the tire width direction, The angle of the first sub-groove central inclined portion with respect to the tire circumferential direction is larger than the angle of the first main groove central inclined portion with respect to the tire circumferential direction. and, at a position where the second sub groove central inclined portion faces the second main groove central inclined portion in the tire width direction, an angle of the second sub groove central inclined portion with respect to the tire circumferential direction is larger than an angle of the first main groove central inclined portion with respect to the tire circumferential direction. Pneumatic tires. Effect of the Invention

[0008] According to this embodiment, the contact area can be increased even if the tire internal pressure is set low. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a tread pattern of a pneumatic tire according to an embodiment of the present invention. [Diagram 2] Enlarged view of the main part of Figure 1 [Diagram 3] Cross section AA of Figure 1 [Figure 4] FIG. 1 is a diagram showing a tread pattern and a ground contact shape of a pneumatic tire according to an embodiment of the present invention. [Diagram 5]FIG. 1 is a diagram showing a tread pattern and a ground contact shape of a pneumatic tire according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment will be described with reference to the drawings.

[0011] The pneumatic tire (hereinafter, simply referred to as the tire) according to this embodiment comprises a pair of left and right beads and sidewalls, and a tread provided between the left and right sidewalls so as to connect the radially outer ends of the left and right sidewalls, and can adopt a general tire structure except for the tread pattern.

[0012] As shown in FIG. 1, on the tread surface of a tread 10, two main grooves 12 extending in the tire circumferential direction CD are provided at an interval in the tire width direction WD across the tire equatorial plane CL.

[0013] The main groove 12 is a wide groove that extends in the tire circumferential direction, and includes not only straight grooves but also zigzag grooves. The main groove 12 preferably has a groove width of 10 mm or more and a groove depth of 3 mm or more. In this embodiment, the groove width is set to 14 mm and the groove depth is set to 5 mm.

[0014] In this specification, the groove width refers to the distance between the open ends (the outer ends in the tire radial direction) of the groove, and in the case of a zigzag groove, refers to the groove width at the narrowest point.

[0015] 2, the main groove 12 has a groove wall 12a on the inner side in the tire width direction extending along the tire circumferential direction CD without bending in a zigzag shape, and a groove wall 12b on the outer side in the tire width direction extending in the tire circumferential direction while bending in the tire width direction WD. As a result, a groove centerline Rm passing through the groove width center of the main groove 12 (the widthwise center at each position in the length direction of the main groove) also extends in the tire circumferential direction while bending in the tire width direction WD.

[0016] The tread 10 is provided with a center land portion 14 sandwiched between the two main grooves 12, and a pair of left and right shoulder land portions 16 formed between the main grooves 12 and a ground contact edge E.

[0017] The ground contact edge E is the outermost position of the ground contact surface in the tire width direction WD. The ground contact surface refers to the surface of the tread that comes into contact with the road surface when the tire is mounted on a regular rim, inflated with an internal pressure of 140 kPa, placed vertically on a flat road surface, and a load of 88% of the load corresponding to the load index is applied.

[0018] 1 to 3, the central land portion 14 is provided with a central sub-groove 18 extending in the tire circumferential direction CD, which has a narrower groove width and a shallower groove depth than the main groove 12. The central sub-groove 18 preferably has a groove width of 50% or less than that of the main groove 12 and a groove depth of 60% or less than that of the main groove 12. In this embodiment, the groove width is 3 mm and the groove depth is 2 mm.

[0019] In the tire according to this embodiment, the center sub groove 18 is straight and extends parallel to the tire circumferential direction CD. At the position facing the tire width direction WD, the angle of the groove center line Rm of the main groove 12 relative to the tire circumferential direction CD is larger than the angle of the groove center line Rc passing through the groove width center of the center sub groove 18 relative to the tire circumferential direction CD.

[0020] The center sub groove 18 is preferably provided in the center land portion 14 so as to bisect the center land portion 14 in the tire width direction WD and coincide with the tire equatorial plane CL. In other words, the center sub groove 18 is preferably provided in the center land portion 14 so that the groove center line Rc of the center sub groove 18 coincides with the tire equatorial plane CL.

[0021] In the tire according to this embodiment, as shown in FIG. 1, the central land portion 14 does not have any grooves intersecting with the central sub groove 18, and the central land portion 14 is made of a rib-shaped land portion that continues in the tire circumferential direction CD.

[0022] 1 to 3, the pair of shoulder land portions 16 are provided with shoulder sub-grooves 20, 20 extending in the tire circumferential direction CD, which have a narrower groove width and a shallower groove depth than the main groove 12. The shoulder sub-groove 20 preferably has a groove width of 50% or less than that of the main groove 12 and a groove depth of 60% or less than that of the main groove 12, and in this embodiment, the groove width is 3 mm and the groove depth is 2 mm.

[0023] The shoulder land portion 16 is divided by a shoulder sub-groove 20 into an inner shoulder land portion 16A and an outer shoulder land portion 16B.

[0024] In the tire according to this embodiment, the shoulder sub groove 20 can be provided at any position in the shoulder land portion 16, but it is preferable to provide the shoulder sub groove 20 on the ground edge side of the width direction center of the shoulder land portion 16. In other words, it is preferable to provide the shoulder sub groove 20 so that the area of ​​the inner shoulder land portion 16A is larger than the area of ​​the outer shoulder land portion 16B, and for example, it is preferable to provide the shoulder sub groove 20 so that the area of ​​the inner shoulder land portion 16A is 1.1 to 1.6 times (1.5 times in the proposal) that of the outer shoulder land portion 16B.

[0025] It is preferable that the shoulder sub-groove 20 is a groove extending in the tire circumferential direction CD in a zigzag shape and consisting of a first groove portion 21 extending at an incline with respect to the tire circumferential direction CD and a second groove portion 22 extending at an incline in the opposite direction to the first groove portion 21 with respect to the tire circumferential direction CD and being shorter than the first groove portion 21.

[0026] At least a portion of the first groove portion 21 and the second groove portion 22 is preferably inclined in the same direction with respect to the tire circumferential direction as the groove wall 12b of the main groove 12 facing the tire width direction WD. More preferably, the first groove portion 21 and the second groove portion 22 extend parallel to the groove wall 12b of the main groove 12 facing the tire width direction WD.

[0027] In the tire according to this embodiment, it is preferable that, at a position opposite to the tire width direction WD, the angle of the groove centerline Rs passing through the groove width center of the shoulder sub-groove 20 relative to the tire circumferential direction CD is greater than the angle of the groove centerline Rm of the main groove 12 relative to the tire circumferential direction CD.

[0028] The shoulder sub-grooves 20, 20 preferably have a dimple 23 provided on the inner side in the tire width direction of the second groove portion 22. The dimple 23 is a recess whose depth is equal to or less than the groove depth of the second groove portion 22, and is formed so as to extend from the second groove portion 22 toward the inner side in the tire width direction and increase the groove width of the second groove portion 22. The depth of the dimple 23 is not particularly limited, but is preferably 50 to 100% of the depth of the second groove portion 22, for example, and is formed to 2 mm in this embodiment.

[0029] As shown in Figs. 1 and 2, the shoulder land portion 16 preferably has a plurality of lateral grooves 30, 40, 50 extending in the tire width direction WD provided at intervals in the tire circumferential direction CD.

[0030] In the tire according to this embodiment, a plurality of first lateral grooves 30 extending in the tire width direction WD are provided at intervals in the tire circumferential direction CD in the inner shoulder land portion 16A provided on the tire width direction inner side of the shoulder sub-groove 20. The first lateral grooves 30 are provided so as to cross the inner shoulder land portion 16A so as to connect the main groove 12 and the shoulder sub-groove 20. The angle of the groove center line R1 passing through the groove width center with respect to the tire circumferential direction CD increases toward the tire width direction WD as it moves toward the outer side in the tire width direction.

[0031] The groove width and groove depth of the first transverse groove 30 are not particularly limited, but for example, it is preferable that the groove width is 30 to 50% of the main groove 12 and the groove depth is 50 to 100% of the main groove 12, and in this embodiment, the groove width is 5 mm and the groove depth is 4 mm.

[0032] In the tire according to this embodiment, a plurality of second lateral grooves 40 and a plurality of third lateral grooves 50 extending in the tire width direction WD are provided at intervals in the tire circumferential direction CD in the outer shoulder land portion 16B provided on the tire width direction outer side of the shoulder sub-groove 20. The second lateral grooves 40 and the third lateral grooves 50 are alternately arranged in the tire circumferential direction CD.

[0033] The second lateral grooves 40 extend from the shoulder sub-groove 20 toward the outside in the tire width direction and terminate within the outer shoulder land portion 16B without reaching the ground contact edge E. A groove centerline R2 passing through the groove width center of the second lateral groove 40 has a larger angle with respect to the tire circumferential direction CD than the groove centerline R1 of the first lateral groove 30. The groove centerline R2 of the second lateral groove 40 has a larger angle with respect to the tire circumferential direction CD as it approaches the tire width direction WD toward the outside in the tire width direction.

[0034] The second lateral groove 40 may be provided so as to face the first lateral groove 30 provided in the inner shoulder land portion 16A with the shoulder sub-groove 20 interposed therebetween.

[0035] The groove width and groove depth of the second transverse grooves 40 are not particularly limited, but it is preferable that the groove width is 30 to 50% of that of the main grooves 12 and the groove depth is 30 to 50% of that of the main grooves 12, for example.

[0036] The third lateral groove 50 extends in the tire width direction WD from the ground contact edge E toward the shoulder sub-groove 20 and terminates in the outer shoulder land portion 16B without communicating with the shoulder sub-groove 20. A groove centerline R3 passing through the groove width center of the third lateral groove 50 has a larger angle with respect to the tire circumferential direction CD than the groove centerline R1 of the first lateral groove 30 and the groove centerline R2 of the second lateral groove 40. The groove centerline R3 of the third lateral groove 50 has a larger angle with respect to the tire circumferential direction CD as it approaches the tire width direction WD toward the outer side in the tire width direction.

[0037] The inner end of the third lateral groove 50 in the tire width direction may be provided to face the second groove portion 22 of the shoulder sub-groove 20 in the tire width direction WD. Also, the inner end of the third lateral groove 50 in the tire width direction may be located outward in the tire width direction from the outer end of the second lateral groove 40 in the tire width direction so as not to overlap with the second lateral groove 40 in the tire width direction WD.

[0038] The groove width and groove depth of the third transverse groove 50 are not particularly limited, but it is preferable that the groove width is 30 to 50% of that of the main groove 12 and the groove depth is 50 to 100% of that of the main groove 12, for example.

[0039] In the tire according to this embodiment, the main grooves 12, shoulder sub-grooves 20, first lateral grooves 30, second lateral grooves 40 and third lateral grooves 50 provided in the tread 10 are offset by a predetermined distance in the tire circumferential direction CD on both sides of the tire equatorial plane CL, but each of the grooves 12, 18, 20, 30, 40, 50 and the land portions formed thereby have a symmetrical shape with respect to the tire equatorial plane CL.

[0040] In the tread 10, when the areas of the center land portion 14 and the shoulder land portions 16 within the contact width (i.e., between the left and right contact edges E) are Ac and As, respectively, it is preferable that the area ratio (Ac / (Ac+2As)) of the center land portion 14 to the total area (Ac+2As) of the center land portion 14 and the pair of shoulder land portions 16 within the contact width is set to 30 to 35%, and the area ratio (As / (Ac+2As)) of the shoulder land portions 16 to the total area (Ac+2As) is set to 30 to 35%. In this embodiment, the area ratio (Ac / (Ac+2As)) of the center land portion 14 is set to 31%, and the area ratios (As / (As+2As)) of the pair of shoulder land portions 16 are each set to 34%.

[0041] In addition, it is preferable that the total opening area of ​​the main groove 12, center sub-groove 18, shoulder sub-groove 20, dimples 23, first lateral groove 30, second lateral groove 40 and third lateral groove 50 provided in the tread 10 is 25% or less of the area inside the contact width (i.e., between the left and right contact edges E).

[0042] Any tread rubber can be used without any particular limitation as the tread rubber constituting the tread 10. As one example, it is preferable to use a tread rubber having a tan δ of 0.933 at 0° C. and a difference between tan δ at 30° C. and tan δ at 60° C. of 0.13 to 0.17.

[0043] The tan δ at 0°C, 30°C, and 60°C are values ​​measured in accordance with K6394-2007 using a viscoelasticity spectrometer (manufactured by Toyo Seiki Seisakusho) at temperatures of 0°C, 30°C, and 60°C, with an elongation deformation strain rate of 10%±2% and a vibration frequency of 20 Hz.

[0044] In the tire according to the present embodiment configured as described above, sub-grooves 18, 20 that extend in the tire circumferential direction CD and have a narrower groove width than the main groove 12 are provided in the center land portion 14 and shoulder land portion 16 formed by two main grooves 12 extending in the tire circumferential direction CD. Therefore, while suppressing a decrease in rigidity of each land portion 14, 16, the tire circumferential length (contact length) of the ground contact portion in the tire width direction WD can be made uniform, and the contact area can be expanded while obtaining a high ground contact pressure.

[0045] In the tire of this embodiment, the center land portion 14 is a rib-shaped land portion that is continuous in the circumferential direction of the tire and has no lateral grooves, and the shoulder land portion 16 is provided with multiple lateral grooves 30, 40, 50 spaced apart in the circumferential direction of the tire, making it easier for the shoulder land portion 16 to come into contact with the ground and making it possible to make the contact length uniform in the tire width direction WD.

[0046] In the tire according to this embodiment, the angle of the groove centerline Rm of the main groove 12 relative to the tire circumferential direction CD is larger than the angle of the groove centerline Rc of the center sub-groove 18, and the angle of the groove centerline Rs of the shoulder sub-groove 20 relative to the tire circumferential direction CD is larger than the angle of the groove centerline Rm of the main groove 12, so that the grooves 12, 18, 20 extending in the tire circumferential direction CD provided at positions closer to the ground contact edge E have a larger inclination angle relative to the tire circumferential direction CD. As a result, the land portions 14, 16 provided in the tread 10 are more susceptible to the influence of the grooves 12, 18, 20 toward the ground contact edge E, and the ground contact length becomes longer in the outer parts in the tire width direction, which tend to have a shorter ground contact length compared to the center part in the tire width direction, and the ground contact length can be made uniform in the tire width direction WD.

[0047] In the tire according to this embodiment, the angle of the groove center line of the lateral grooves 30, 40, 50 provided in the shoulder land portion 16 becomes larger as it moves outward in the tire width direction. Therefore, the shoulder land portion 16 is more susceptible to the influence of the lateral grooves 30, 40, 50 as it approaches the contact end E, and the contact length is less likely to become short near the contact end, making it possible to uniformize the contact length in the shoulder land portion 16.

[0048] In the tire according to this embodiment, the shoulder sub-groove 20 is provided on the side of the contact end from the widthwise center of the shoulder land portion 16, so that areas with locally short contact lengths are less likely to occur near the widthwise center of the shoulder land portion 16, and the contact length in the tire width direction WD can be made uniform.

[0049] In the tire of this embodiment, the area ratio (Ac / (Ac+As)) of the center land portion 14 to the total (Ac+2As) of the areas of the center land portion 14 and the pair of shoulder land portions 16 within the contact width is set to 30 to 35%, and the area ratio (As / (Ac+2As)) of one of the shoulder land portions 16 to the total (Ac+2As) is set to 30 to 35%, thereby reducing the area difference between the center land portion 14 and the shoulder land portions 16, thereby making it possible to equalize the ground contact pressure.

[0050] In the tire according to the present embodiment, the dimples 23 are provided in the shoulder sub-grooves 20, so that the surface area of ​​the tread 10 is increased and heat dissipation performance can be ensured.

[0051] The tire according to the present embodiment can be applied to various types of tires such as tires for passenger cars and tires for heavy loads, but is preferably used as a tire for racing vehicles such as those used in drag races.

[0052] The above embodiments are merely examples, and the scope of the invention is not limited thereto. Various omissions, substitutions, and modifications can be made to the above embodiments without departing from the spirit of the invention. The above embodiments and their modifications are intended to be included in the scope of the invention and its equivalents as set forth in the claims. EXAMPLES

[0053] In order to demonstrate the effects of the above embodiment, pneumatic tires (size: 315 / 40R18) of an example and a comparative example were produced. The prototype tires of the example and the comparative example have the same tire structure except for the tread pattern.

[0054] The tire of the example is a tire according to the above embodiment, and has the tread shown in FIGS.

[0055] The comparative tire has a tread as shown in Fig. 5. That is, in the tread 100 of the comparative tire, two main grooves 112 extending in the tire circumferential direction CD are provided on either side of the tire equatorial plane CL, a center land portion 114 is formed between the main grooves 112, and a pair of left and right shoulder land portions 116, 116 are formed between the main grooves 112 and the ground contact edge E. The center land portion 114 and the shoulder land portions 116 are not provided with secondary grooves extending in the tire circumferential direction.

[0056] In addition, in the comparative example tire, if the areas of the center land portion 114 and the shoulder land portion 116 within the contact width (i.e., between the left and right contact edges E) are Bc and Bs, respectively, the area ratio (Bc / (Bc+Bs)) of the center land portion 114 to the total (Bc+2Bs) of the areas of the center land portion 114 and the pair of shoulder land portions 116 within the contact width is set to 43%, and the area ratio (Bs / (Bc+2Bs)) of one of the shoulder land portions 116 to the total (Bc+2Bs) is set to 29%.

[0057] For each prototype tire of the Examples and Comparative Examples, the tire was mounted on a regular rim and inflated to an internal pressure of 140 kPa. The tire was then placed vertically on a flat road surface and a load of 88% of the load corresponding to the load index was applied to measure the contact shape of the tread that came into contact with the road surface, as well as the average contact pressure of the center land area and the average contact pressure of the shoulder land area.

[0058] 5, the contact patch shape of the comparative tire had areas with short contact lengths near the main groove 112 of the center land portion 114 and near the widthwise center of the shoulder land portion 116, resulting in bias in the contact patch length in the tire width direction WD. The average contact pressure of the center land portion 114 was 14 N / cm2, and the average contact pressure of the shoulder land portion 116 was 22 N / cm2, resulting in bias in the contact pressure between the center land portion 114 and the shoulder land portion 116.

[0059] As shown by the two-dot chain line in Figure 4, the contact patch shape of the tire of the embodiment does not have any areas with locally short contact patch length near the main groove 12 of the center land portion 14 or near the widthwise center of the shoulder land portion 16, and the contact patch length in the tire width direction WD can be made uniform and the contact patch area can be expanded. In addition, the average contact pressure of the center land portion 14 and the shoulder land portion 16 was both 24N / cm2, and the contact pressure between the land portions could be made uniform while obtaining high contact pressure. [Explanation of symbols]

[0060] Reference Signs List 10...tread, 12...main groove, 12a...inner groove wall, 12b...outer groove wall, 14...center land portion, 16...shoulder land portion, 16A...inner shoulder land portion, 16B...outer shoulder land portion, 18...center sub-groove, 20...shoulder sub-groove, 21...first groove portion, 22...second groove portion, 23...dimple, 30...first lateral groove, 40...second lateral groove, 50...third lateral groove

Claims

1. Two main grooves extending in a tire circumferential direction provided in the tread; a center land portion extending in a tire circumferential direction and formed between the two main grooves; a pair of shoulder land portions formed between a ground contact edge and the main groove; A center sub-groove provided in the center land portion, the center sub-groove having a groove width narrower than that of the main groove and extending in the tire circumferential direction; a shoulder sub-groove provided in the shoulder land portion, the shoulder sub-groove having a groove width narrower than that of the main groove and extending in the tire circumferential direction, The center sub groove is straight and extends parallel to the tire circumferential direction, a groove center line of the main groove extends in a zigzag manner in the tire circumferential direction and is made up of a first main groove central inclined portion that extends at an incline toward one side in the tire width direction with respect to the tire circumferential direction, and a second main groove central inclined portion that extends at an incline in the opposite direction to the first main groove central inclined portion with respect to the tire circumferential direction and is shorter than the first main groove central inclined portion; a groove center line of the shoulder sub-groove extends in a zigzag manner in the tire circumferential direction and is made up of a first sub-groove central inclined portion that extends at an incline toward one side in the tire width direction with respect to the tire circumferential direction, and a second sub-groove central inclined portion that extends at an incline in the opposite direction to the first sub-groove central inclined portion with respect to the tire circumferential direction and is shorter than the first sub-groove central inclined portion; At least a portion of the first sub-groove central inclined portion faces the first main groove central inclined portion in the tire width direction, and at least a portion of the second sub-groove central inclined portion faces the second main groove central inclined portion in the tire width direction, At a position where the first sub-groove center inclined portion faces the first main groove center inclined portion in the tire width direction, an angle of the first sub-groove center inclined portion with respect to the tire circumferential direction is larger than an angle of the first main groove center inclined portion with respect to the tire circumferential direction, a first main groove central inclined portion and a second sub groove central inclined portion, the first main groove central inclined portion being spaced apart from the first sub groove central inclined portion in a tire width direction;

2. Two main grooves extending in a tire circumferential direction provided in the tread; a center land portion extending in a tire circumferential direction and formed between the two main grooves; a pair of shoulder land portions formed between a ground contact edge and the main groove; A center sub-groove provided in the center land portion, the center sub-groove having a groove width narrower than that of the main groove and extending in the tire circumferential direction; a shoulder sub-groove provided in the shoulder land portion, the shoulder sub-groove having a groove width narrower than that of the main groove and extending in the tire circumferential direction, The shoulder sub-groove has a plurality of dimples with a widened groove width spaced apart in the tire circumferential direction, The shoulder sub-groove includes a first groove portion extending at an angle with respect to the tire circumferential direction and a second groove portion extending at an angle in the opposite direction to the first groove portion with respect to the tire circumferential direction and shorter than the first groove portion, and extends in a zigzag manner in the tire circumferential direction. The dimple is provided on an inner side of the second groove portion in a tire width direction and is a depression having a depth equal to or less than a groove depth of the second groove portion.

3. The center land portion is composed of a rib-shaped land portion that is continuous in the tire circumferential direction, The pneumatic tire according to claim 1 or 2, wherein the pair of shoulder land portions include a plurality of lateral grooves provided at intervals in the tire circumferential direction.

4. The pair of shoulder land portions each include a plurality of lateral grooves spaced apart in the tire circumferential direction, The pneumatic tire according to any one of claims 1 to 3, wherein an angle of a groove center line of the lateral groove with respect to a tire circumferential direction increases toward the outer side in the tire width direction.

5. The pneumatic tire according to any one of claims 1 to 4, wherein the shoulder sub-groove is provided on the side of the tread edge from the center in the width direction of the shoulder land portion.

6. a ratio of an area of ​​the center land portion to a total area of ​​the center land portion and the shoulder land portion within a contact width is 30% or more and 35% or less; The pneumatic tire according to any one of claims 1 to 5, wherein a ratio of an area of ​​the shoulder land portion to the total is 30% or more and 35% or less.

Images