Pneumatic tire

Abstract

To provide a pneumatic tire improved in the grip performance.SOLUTION: A pneumatic tire comprises: a plurality of first width direction grooves 4 arranged at an outermost land part when the tire is attached to a vehicle which extend in a tire width direction and whose one end terminates in the outermost land part when the tire is attached to the vehicle; and a plurality of second width direction grooves 5 which extend in the tire width direction and whose one end at least terminates in the outermost land part when the tire is attached to the vehicle. The first width direction groove 4 and the second width direction groove 5 are separated from each other in a tire circumferential direction and alternatively arranged in the tire circumferential direction. One of the first width direction grooves 4 and one of the second width direction grooves 5 adjacent to the one of the first width direction grooves 4 at one side in the tire circumferential direction form a couple. The one of the first width direction grooves 4 constituting the couple extends from the tire width direction outer (inner) side to the inner (outer) side, and the one of the second width direction grooves 5 constituting the couple extends from the tire width direction outer (inner) side to the inner (outer) side toward the other side in the tire circumferential direction.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Conventionally, in a pneumatic tire that travels at a high speed such that the traveling speed exceeds 150 km / h, by disposing a width-direction groove extending in the tire width direction in the outer shoulder land portion when the tire is mounted on a vehicle, the rigidity of the land portion is moderately relaxed to improve the grip performance has been proposed.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique such as Patent Document 1, since a plurality of width-direction grooves (71) extending in the same direction are mainly arranged, the rigidity is high with respect to the input from the extending direction of the width-direction groove, while for example, the rigidity is low with respect to the input from the vertical direction with respect to the extending direction of the width-direction groove, and there is a problem that the land portion is easily deformed, and there is room for improvement in improving the grip performance.

[0005] An object of the present invention is to provide a pneumatic tire with improved grip performance.

Means for Solving the Problems

[0006] The gist configuration of the present invention is as follows. (1) A pneumatic tire having one or more circumferential main grooves extending in the tire circumferential direction on a tread surface, having a plurality of land portions partitioned between the circumferential main groove and the tread end or between the circumferential main grooves, On the outermost land portion in the tire width direction on the outer side when the tire is mounted on a vehicle, which is the outermost land portion when the tire is mounted on a vehicle, there are a plurality of first width direction grooves extending in the tire width direction and having one end terminating within the outermost land portion when the tire is mounted on the vehicle, and a plurality of second width direction grooves extending in the tire width direction and having at least one end terminating within the outermost land portion when the tire is mounted on the vehicle. The first width direction grooves and the second width direction grooves are alternately arranged in the tire circumferential direction while being spaced apart from each other in the tire circumferential direction. One of the first width direction grooves and one of the second width direction grooves adjacent to the one first width direction groove on one side in the tire circumferential direction form a pair. The one first width direction groove constituting the pair has a first portion extending in one side in the tire circumferential direction from the outer side to the inner side in the tire width direction. The one second width direction groove constituting the pair extends in the other side in the tire circumferential direction from the outer side to the inner side in the tire width direction. The inner end in the tire width direction of the one second width direction groove constituting the pair is located on the outer side in the tire width direction than the inner end in the tire width direction of the one first width direction groove constituting the pair. It further includes a shallow groove having one end communicating with the other end of the first width direction groove. The groove depth of the shallow groove is shallower than the groove depth of the first width direction groove. The other end of the shallow groove communicates with the circumferential main groove, and the pneumatic tire is characterized in this.

[0007] Here, the "tread surface" refers to the surface extending over the entire circumference in the tire circumferential direction of the outer surface of the tread that comes into contact with the road surface in a state where a pneumatic tire is mounted on an application rim, filled with a specified internal pressure, and loaded with a maximum load. Also, the "tread end" refers to the two outermost points in the tire width direction of the above tread surface. Also, the "circumferential main groove" refers to a groove extending in the tire circumferential direction, and in a reference state where a pneumatic tire is mounted on an application rim, filled with a specified internal pressure, and unloaded, the groove width (opening width) is 2 mm or more. Also, the "first widthwise groove" refers to a groove extending in the tire width direction, where the groove width (opening width) in the reference state is 2 mm or more over 80% or more of its extension length, and the "second widthwise groove" refers to a groove extending in the tire width direction, where the groove width (opening width) in the reference state is 2 mm or more over 80% or more of its extension length.

[0008] In this specification, the "applicable rim" refers to the standard rim (Measuring Rim in the ETRTO's STANDARDS MANUAL, Design Rim in the TRA's YEAR BOOK) in the applicable size described in or to be described in the industrial standards effective in the region where the tire is produced and used, such as the JATMA YEAR BOOK of JATMA (Japan Automobile Tire Association) in Japan, the STANDARDS MANUAL of ETRTO (The European Tyre and Rim Technical Organisation) in Europe, and the YEAR BOOK of TRA (The Tire and Rim Association, Inc.) in the United States (that is, the above "rim" includes sizes that may be included in the above industrial standards in the future in addition to the current sizes. Examples of "sizes to be described in the future" include the sizes described as "FUTURE DEVELOPMENTS" in the ETRTO 2013 edition). In the case of sizes not described in the above industrial standards, it refers to a rim with a width corresponding to the bead width of the tire. Also, the "specified internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity of a single wheel in the applicable size and ply rating described in the above JATMA, etc. In the case of sizes not described in the above industrial standards, the "specified internal pressure" shall refer to the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle on which the tire is mounted. Also, the "maximum load" refers to the load corresponding to the above maximum load capacity.

[0009] (2) The groove depth of the shallow groove is 2.5 mm or less, for the pneumatic tire according to (1) above.

[0010] (3) The pneumatic tire according to (1) or (2) above, wherein the shallow groove extends obliquely at an inclination angle of 40 to 60° with respect to the tire circumferential direction. Here, the "inclination angle" means the inclination angle of the line segment connecting both ends when the shallow groove does not extend linearly.

[0011] (4) The pneumatic tire according to any one of (1) to (3) above, wherein the shallow groove communicates with an end on one side in the tire circumferential direction of the first width direction groove.

[0012] (5) The pneumatic tire according to any one of (1) to (4) above, wherein the first width direction groove, the second width direction groove, and the shallow groove are provided only on the outermost land portion when the tire is mounted on the vehicle.

[0013] (6) The pneumatic tire according to any one of (1) to (5) above, wherein the second width direction groove communicates with the outer tread edge when the tire is mounted on the vehicle.

[0014] (7) A pneumatic tire having one or more circumferential main grooves extending in the tire circumferential direction on the tread surface, having a plurality of land portions partitioned between the circumferential main groove and the tread edge or between the circumferential main grooves, a plurality of first width direction grooves extending in the tire width direction and having one end terminated within the outermost land portion when the tire is mounted on the vehicle, which is the outermost land portion on the outermost side in the tire width direction of the tire when the tire is mounted on the vehicle, and a plurality of second width direction grooves extending in the tire width direction and having at least one end terminated within the outermost land portion when the tire is mounted on the vehicle, the first width direction grooves and the second width direction grooves are alternately arranged in the tire circumferential direction while being separated from each other in the tire circumferential direction, one of the first width direction grooves and one of the second width direction grooves adjacent to the one first width direction groove on one side in the tire circumferential direction form a pair, the one first width direction groove constituting the pair has a first portion extending in one side in the tire circumferential direction from the inner side to the outer side in the tire width direction, One of the second widthwise grooves constituting the pair extends from the inner side to the outer side in the tire width direction toward the other side in the tire circumferential direction. The outer end in the tire width direction of one of the second widthwise grooves constituting the pair is located more outward in the tire width direction than the outer end in the tire width direction of one of the first widthwise grooves constituting the pair. It further includes a shallow groove having one end communicating with the other end of the first widthwise groove. The groove depth of the shallow groove is shallower than the groove depth of the first widthwise groove. The other end of the shallow groove communicates with the circumferential main groove, and the pneumatic tire is characterized by this.

[0015] (8) The pneumatic tire according to (7) above, wherein the groove depth of the shallow groove is 2.5 mm or less.

[0016] (9) The pneumatic tire according to (7) or (8) above, wherein the shallow groove extends obliquely at an inclination angle of 40 to 60° with respect to the tire circumferential direction.

[0017] (10) The pneumatic tire according to any one of (7) to (9) above, wherein the shallow groove communicates with an end on one side in the tire circumferential direction of the first widthwise groove.

[0018] (11) The pneumatic tire according to any one of (7) to (10) above, wherein the first widthwise groove, the second widthwise groove, and the shallow groove are provided only on the outermost land portion when mounted on the vehicle.

[0019] (12) The pneumatic tire according to any one of (7) to (11) above, wherein the second widthwise groove communicates with the outer tread end when mounted on the vehicle.

Advantages of the Invention

[0020] According to the present invention, it is possible to provide a pneumatic tire with improved grip performance.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

MODE FOR CARRYING OUT THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0023] Regarding the internal structure etc. of the pneumatic tire (hereinafter, also simply referred to as "tire") according to one embodiment of the present invention, since it can be the same as the conventional one, detailed description is omitted. On the other hand, as an example, the tire can be provided with a pair of bead portions, a carcass straddling between the pair of bead portions in a toroidal shape, and a belt disposed on the outer side in the tire radial direction of the crown portion of the carcass.

[0024] FIG. 1 is a view showing a tread pattern of a pneumatic tire according to one embodiment of the present invention. In the following description, dimensions etc. refer to the dimensions in the reference state unless otherwise specified.

[0025] As shown in FIG. 1, this tire has one or more (two in the illustrated example) circumferential main grooves 2 (2a, 2b) extending in the tire circumferential direction on the tread surface 1. And this tire has a plurality of land portions 3 (3a, 3b (3b1, 3b2)) partitioned between the circumferential main groove 2 and the tread end TE or between the circumferential main grooves 2 (2a, 2b). Specifically, on the outer side when mounted on a vehicle with the tire equatorial plane CL as a boundary, the outermost land portion 3a when mounted on a vehicle is partitioned by the circumferential main groove 2a and the tread end TE. Also, on the inner side when mounted on a vehicle with the tire equatorial plane CL as a boundary, the inner land portion 3b when mounted on a vehicle is partitioned by between the circumferential main grooves 2a, 2b or by the circumferential main groove 2b and the tread end TE. Between the circumferential main grooves 2a, 2b, the inner land portion 3b2 of the inner land portion when mounted on a vehicle is partitioned, and the outer land portion 3b1 of the inner land portion when mounted on a vehicle is partitioned by the circumferential main groove 2a and the tread end TE.

[0026] This tire has a plurality of first widthwise grooves 4 extending in the tire width direction and having one end terminated within the outermost land portion 3a when mounted on a vehicle, which is the outermost land portion in the tire width direction on the outer side when the tire is mounted on the vehicle, and a plurality of second widthwise grooves 5 extending in the tire width direction and having at least one end (both ends in this example) terminated within the outermost land portion 3a when mounted on the vehicle.

[0027] As shown in the figure, the first widthwise grooves 4 and the second widthwise grooves 5 are arranged alternately in the tire circumferential direction while being spaced apart from each other in the tire circumferential direction. In other words, one first widthwise groove 4 and one second widthwise groove 5 adjacent to the one first widthwise groove 4 on one side in the tire circumferential direction form a pair, and a plurality of such pairs are provided at intervals in the tire circumferential direction. The pitch interval in the tire circumferential direction of the first widthwise grooves 4 is not particularly limited, but can be, for example, 40 to 140 mm. Also, the pitch interval in the tire circumferential direction of the second widthwise grooves 5 is not particularly limited, but can be, for example, 40 to 140 mm. The shortest distance between the paired first widthwise grooves 4 and second widthwise grooves 5 is not particularly limited, but can be, for example, 15 to 60 mm.

[0028] One first widthwise groove 4 constituting a pair has a first portion 41 extending in one side in the tire circumferential direction from the outer side to the inner side in the tire width direction. Further, the first widthwise groove 4 further has a second portion 42 extending in one side in the tire circumferential direction from the inner side end in the tire width direction of the first portion 41. With this second portion 42, drainage performance can be further ensured.

[0029] The groove width (opening width) of the first widthwise groove 4 is not particularly limited, but in view of the balance between drainage (conforming to the regulations when used for a racing tire; the same applies hereinafter) and the rigidity of the land portion, it can be, for example, 5 to 20 mm. The groove depth (maximum depth) of the first widthwise groove 4 is not particularly limited, but in view of the balance between drainage and the rigidity of the land portion, it can be, for example, 5 to 8 mm. Also, the inclination angle of the first portion 41 with respect to the tire width direction is not particularly limited, but it can be, for example, 10 to 20°. By setting it to 20° or less, the rigidity against the input in the width direction (the rigidity against shear deformation due to the input from the outer side to the inner side in the width direction during the vehicle turning travel) can be increased, and by setting it to 10° or more, as will be described later, the difference in the inclination direction from the second widthwise groove 5 can be made clearer, and both can improve the grip performance. Also, the inclination angle of the second portion 42 with respect to the tire circumferential direction is not particularly limited, but it can be, for example, 10 to 15°.

[0030] Also, as shown in the figure, one of the second widthwise grooves 5 that form a pair extends from the outer side to the inner side in the tire width direction toward the other side in the tire circumferential direction. That is, the first widthwise groove 4 and the second widthwise groove 5 are inclined in opposite directions in the tire circumferential direction with respect to the tire width direction.

[0031] The groove width (opening width) of the second widthwise groove 5 is not particularly limited, but in view of the balance between drainage performance (compliance with regulations when used for racing tires; the same applies hereinafter) and the rigidity of the land portion, it can be, for example, 5 to 20 mm. The groove depth (maximum depth) of the second widthwise groove 5 is not particularly limited, but in view of the balance between drainage performance and the rigidity of the land portion, it can be, for example, 5 to 8 mm. Also, the inclination angle of the second widthwise groove 5 with respect to the tire width direction is not particularly limited, but it can be, for example, 5 to 15°. By setting it to 15° or less, the rigidity against the input in the width direction (the rigidity against shear deformation due to the input from the outer side to the inner side in the width direction during vehicle turning) can be increased, and by setting it to 5° or more, as will be described later, the difference in the inclination direction from the first widthwise groove 4 can be made clearer, and both can improve the grip performance.

[0032] Here, the inner end in the tire width direction of one of the second widthwise grooves 5 constituting a pair is located on the outer side in the tire width direction than the inner end in the tire width direction of one of the first widthwise grooves 4 constituting the pair (in this example, the inner end in the tire width direction of the second portion 42). Although not particularly limited, the inner end in the tire width direction of one of the second widthwise grooves 5 constituting a pair is preferably located on the outer side in the tire width direction by a distance corresponding to 50 to 80% of the width of the first widthwise groove 4 in the tire width direction (the width in the tire width direction when projected in the tire circumferential direction). Also, in the illustrated example, the second widthwise groove 5 communicates with the outer tread end TE when the tire is mounted on the vehicle (at its outer end in the tire width direction). In the illustrated example, one of the first widthwise grooves 4 constituting a pair and one of the second widthwise grooves 5 constituting a pair have an overlapping portion when projected in the tire circumferential direction. This overlapping width is not particularly limited, but in the tire width direction, it can be, for example, 20 to 50% of the width of the first widthwise groove 4 in the tire width direction (the width in the tire width direction when projected in the tire circumferential direction).

[0033] At least a part of the first portion 41 or at least a part of the second portion 42 has a chamfered portion at the opening to the tread surface 1. Thereby, drainage performance is greatly ensured at the time of new product (it becomes easier to conform to the rules when used for a racing tire), and on the other hand, a decrease in rigidity can be suppressed as compared with the case where the opening width is the same up to the groove bottom, and grip performance can be ensured. It is also possible to form a chamfered portion only in the first portion 41 (entire circumference or part) (no chamfered portion is formed in the second portion 42). Alternatively, it is also possible to form a chamfered portion only in the second portion 42 (entire circumference or part) (no chamfered portion is formed in the first portion 41). Alternatively, it is also possible to form chamfered portions in both the first portion 41 (entire circumference or part) and the second portion 42 (entire circumference or part). In this example, chamfered portions are formed on the entire circumference of the first portion 41 and the entire circumference of the second portion 42. Similarly, at least a part (entire circumference or part, entire circumference in this example) of the second widthwise groove 5 has a chamfered portion at the opening to the tread surface 1. Regarding the first widthwise groove 4, in the reference state, the inclination angle of the tapered surface of the chamfered portion of the second portion 42 with respect to the tire radial direction is preferably larger than the inclination angle of the tapered surface of the chamfered portion of the first portion 41 with respect to the tire radial direction. This is because when ensuring drainage performance at the time of new product by the second portion 42, a decrease in rigidity can be further suppressed.

[0034] Further, this tire has only two circumferential main grooves 2a and 2b in the land portion 3b on the inner side when mounted on a vehicle, which is the inner side when the tire is mounted on the vehicle. Thereby, drainage performance and the rigidity of the land portion can be ensured in a well-balanced manner.

[0035] On the outer land portion 3b1 of the inner land portion 3b when mounted on a vehicle, a plurality of third widthwise grooves 6 extending in the tire width direction are arranged. The third widthwise grooves 6 communicate with the tread end TE (at their outer ends in the tire width direction). Thereby, drainage performance can be improved. On the other hand, the third widthwise grooves 6 do not communicate with the circumferential main grooves 2a (at their inner ends in the tire width direction). Thereby, the rigidity of the land portion can be ensured. Between the third widthwise grooves 6 in the tire circumferential direction, fourth widthwise grooves 9 are further arranged. Thereby, drainage performance can be further improved. The fourth widthwise grooves 9 terminate at both ends within the outer land portion 3b1. Thereby, the rigidity of the land portion can be ensured. In this example, the groove width of the fourth widthwise grooves 9 is smaller than the groove width of the third widthwise grooves 6.

[0036] The groove width (opening width) of the third widthwise grooves 6 is not particularly limited, but in view of the balance between drainage performance (compliance with regulations when used for racing tires. The same applies hereinafter.) and the rigidity of the land portion, it can be, for example, 10 to 25 mm. The groove depth (maximum depth) of the third widthwise grooves 6 is not particularly limited, but in view of the balance between drainage performance and the rigidity of the land portion, it can be, for example, 5 to 8 mm. Also, the inclination angle of the third widthwise grooves 6 with respect to the tire width direction is not particularly limited, but it can be, for example, 5 to 15°. By setting it to 15° or less, the rigidity against widthwise input (rigidity against shear deformation caused by an input from the outer side to the inner side in the width direction during vehicle turning) can be increased, and by setting it to 5° or more, the rigidity can be prevented from locally decreasing in the tire circumferential direction. The groove width (opening width) of the fourth widthwise groove 9 is not particularly limited, but in view of the balance between drainage performance (compliance with regulations when used for racing tires; the same applies hereinafter) and the rigidity of the land portion, it can be, for example, 2 to 6 mm. The groove depth (maximum depth) of the fourth widthwise groove 9 is not particularly limited, but in view of the balance between drainage performance and the rigidity of the land portion, it can be, for example, 5 to 8 mm. Also, the inclination angle of the fourth widthwise groove 9 with respect to the tire width direction is not particularly limited, but it can be, for example, 5 to 15°. By setting it to 15° or less, the rigidity against the input in the width direction (the rigidity against shear deformation caused by the input from the outer side to the inner side in the width direction during vehicle turning) can be increased, and by setting it to 5° or more, the rigidity can be prevented from locally decreasing in the tire circumferential direction. It is preferable that at least a part (the entire circumference or a part thereof) of the openings of the third widthwise groove 6 and the fourth widthwise groove 9 is chamfered.

[0037] Also, a plurality of notches 7 communicating with the circumferential main groove 2a are provided inside the circumferential main groove 2a in the tire width direction. Thereby, the rigidity of the land portion provided with the notch 7 can be moderately relaxed to improve the grip performance. Also, since the notch 7 is provided inside the inner land portion 3b when the tire is mounted on the vehicle, it is less affected by the lateral force during cornering.

[0038] The first widthwise groove 4 and the second widthwise groove 5 provided in the outermost land portion 3a when the tire is mounted on the vehicle, and the third widthwise groove 6 provided in the inner land portion 3b when the tire is mounted on the vehicle preferably do not overlap each other or only the chamfered portions overlap when projected in the tire width direction. This is because the balance of the rigidity of the land portion in the tire circumferential direction can be achieved. Similarly, the first widthwise groove 4 and the second widthwise groove 5 provided in the outermost land portion 3a when the tire is mounted on the vehicle, and the fourth widthwise groove 9 provided in the inner land portion 3b when the tire is mounted on the vehicle preferably do not overlap each other or only the chamfered portions overlap when projected in the tire width direction.

[0039] This tire further includes a shallow groove 8 at the outermost land portion 3a when mounted on a vehicle, with one end communicating with the other end of the first width-direction groove 4. The other end of the shallow groove 8 communicates with the circumferential-direction main groove 2b. The groove depth (maximum depth) of the shallow groove 8 is shallower than the groove depth (maximum depth) of the first width-direction groove 4.

[0040] The groove depth (maximum depth) of the shallow groove 8 is preferably 1.0 mm or more and 2.5 mm or less. By setting it to 1.0 mm or more, the drainage performance can be further improved. On the other hand, by setting it to 2.5 mm or less, a decrease in the rigidity of the outermost land portion 3a when the tire is mounted on a vehicle can be suppressed. The groove width (opening width) of the shallow groove 8 is preferably 3.0 to 10.0 mm. By setting it to 3.0 mm or more, the drainage performance can be further improved. On the other hand, by setting it to 10.0 mm or less, a decrease in the rigidity of the outermost land portion 3a when the tire is mounted on a vehicle can be suppressed.

[0041] The shallow groove 8 extends toward one side in the tire circumferential direction from the outer side to the inner side in the tire width direction. The shallow groove 8 preferably extends while being inclined at an inclination angle of 40 to 60° with respect to the tire circumferential direction. By setting it to 40° or more, a decrease in the rigidity of the local land portion due to the formation of an acute angle portion can be suppressed. On the other hand, by setting it to 60° or less, the drainage performance can be further improved.

[0042] The shallow groove 8 preferably communicates with the end of the first width-direction groove 4 (in the illustrated example, the second portion 42) on one side in the tire circumferential direction (in this example, the kick-out side). This is because it can promote the drainage of water that has entered the first width-direction groove 4 through the shallow groove 8 to the circumferential-direction main groove 2a, further improving the drainage performance.

[0043] In this example, the first width-direction groove 4, the second width-direction groove 5, and the shallow groove 8 having the above-described configuration are provided only at the outermost land portion 3a when the tire is mounted on a vehicle. Hereinafter, the operation and effect of the pneumatic tire of the present embodiment will be described.

[0044] The pneumatic tire of the present embodiment first has, at the outermost land portion 3a in the tire width direction on the outer side when mounted on a vehicle, which is the outermost land portion in the tire width direction when mounted on a vehicle, a plurality of first width-direction grooves 4 extending in the tire width direction and having both ends terminated within the outermost land portion 3a when mounted on a vehicle, and a plurality of second width-direction grooves 5 extending in the tire width direction and having at least one end (both ends in this example) terminated within the outermost land portion 3a when mounted on a vehicle. Therefore, the rigidity against an input in the width direction (the rigidity against shear deformation caused by an input from the outer side to the inner side in the width direction during vehicle turning travel) can be increased, and the grip performance can be improved. Also, in the pneumatic tire of the present embodiment, one first width-direction groove 4 that forms a pair has a first portion 41 extending in one side in the tire circumferential direction from the outer side to the inner side in the tire width direction, and one second width-direction groove 5 that forms a pair extends in the other side in the tire circumferential direction from the outer side to the inner side in the tire width direction. As a result, for inputs from various directions, there are always two types of width-direction grooves with extending directions (where the inclination directions with respect to the tire width direction in the tire circumferential direction are opposite to each other), so that the problem that the land portion is likely to deform for an input from a specific direction can be solved, and the grip performance can be improved. Furthermore, according to such a configuration, the first portion 41 and the second width-direction groove 5 have a larger separation distance in the tire circumferential direction as they are closer to the outer side in the tire width direction. Therefore, a large land area can be ensured on the outer side in the tire width direction, and the grip performance can be improved. On the other hand, considering only the direction of inclination, the first portion 41 and the second width-direction groove 5 have a smaller separation distance in the tire circumferential direction as they are closer to the inner side in the tire width direction. However, in the pneumatic tire of the present embodiment, the inner end in the tire width direction of one second width-direction groove 5 that forms a pair is located on the outer side in the tire width direction compared to the inner end in the tire width direction of one first width-direction groove 4 that forms a pair. Therefore, an area where the first width-direction groove 4 and the second width-direction groove 5 approach each other in the tire circumferential direction is minimized, and a large land area can be ensured also on the inner side in the tire width direction, and the grip performance can be improved. As described above, according to the pneumatic tire of the present embodiment, the grip performance can be improved.

[0045] Here, in a tire like the present embodiment, the first width-direction groove 4 closes within the ground contact surface, and when the air in the closed space is compressed and released by a load, pumping noise is generated, resulting in possible pattern noise. On the other hand, the tire of the present embodiment further includes a shallow groove 8 having one end communicating with the other end of the first width-direction groove 4, and the other end of the shallow groove 8 communicates with the circumferential-direction main groove 2b. Thereby, when the first width-direction groove 4 is located within the ground contact surface, the shallow groove 8 functions as an escape path for air, so that the generation of the above-described pattern noise can be suppressed. Furthermore, drainage by such a shallow groove 8 itself and effective drainage by communication between the circumferential-direction main groove 2b and the first width-direction groove 4 due to the shallow groove 8 can further improve drainage performance. Also, since the groove depth of such a shallow groove 8 is shallower than the groove depth of the first width-direction groove 4, a decrease in the rigidity of the land portion can also be suppressed. Note that when wear progresses, the shallow groove 8 may disappear. However, when wear progresses, the groove depth of the first width-direction groove 4 also becomes shallower, so that the possible pumping noise is also reduced.

[0046] Here, it is preferable that the second width-direction groove 5 communicates with the tread edge on the outer side when the tire is mounted on the vehicle. This is because the drainage performance can be further improved.

[0047] Also, it is preferable that one first width-direction groove 4 constituting a pair and one second width-direction groove 5 constituting a pair have an overlapping portion when projected in the tire circumferential direction. This is because it becomes easier to sufficiently secure the extending length of the width-direction groove even considering the arrangement relationship with other grooves (in the example of FIG. 1, the circumferential-direction main groove 2a).

[0048] One first width-direction groove 4 further has a second portion 42 extending in one circumferential direction from the inner end in the tire width direction of the first portion 41, and at least a part of the first portion 41 or at least a part of the second portion 42 preferably has a chamfered portion at the opening to the tread surface. This is because while further improving the drainage performance at the time of new product, a decrease in rigidity can be suppressed as much as possible.

[0049] In the reference state, it is preferable that the inclination angle of the tapered surface of the chamfered portion of the second portion 42 with respect to the tire diameter direction is larger than the inclination angle of the tapered surface of the chamfered portion of the first portion 41 with respect to the tire diameter direction. This is because while further improving the drainage performance at the time of new product, it is possible to suppress a decrease in rigidity as much as possible.

[0050] It is preferable that the inner land portion 3b on the inner side when mounted on the vehicle has only two circumferential main grooves 2a and 2b. Thereby, it is possible to ensure drainage performance and the rigidity of the land portion in a well-balanced manner.

[0051] Here, as another embodiment, both the direction of inclination of the first portion of the first widthwise groove in the tire circumferential direction with respect to the tire width direction and the direction of inclination of the second widthwise groove in the tire circumferential direction with respect to the tire width direction may be opposite to those in the above-described embodiment. That is, the tire of another embodiment has the same basic configuration as the above-described embodiment, has one or more circumferential main grooves extending in the tire circumferential direction on the tread surface, and has a plurality of land portions partitioned between the circumferential main grooves and the tread edge or between the circumferential main grooves. On the outermost land portion on the outer side in the tire width direction when mounted on the vehicle, that is, the outermost land portion when mounted on the vehicle, there are a plurality of first widthwise grooves extending in the tire width direction and having one end terminated within the outermost land portion when mounted on the vehicle, and a plurality of second widthwise grooves extending in the tire width direction and having at least one end (both ends may be acceptable) terminated within the outermost land portion when mounted on the vehicle. The first widthwise grooves and the second widthwise grooves are alternately arranged in the tire circumferential direction while being spaced apart from each other in the tire circumferential direction, and one first widthwise groove and one second widthwise groove adjacent to the one first widthwise groove on one side in the tire circumferential direction form a pair. Further, it further includes a shallow groove 8 having one end communicating with the other end of the first widthwise groove 4. The groove depth of the shallow groove 8 is shallower than the groove depth of the first widthwise groove 4, and the other end of the shallow groove 8 communicates with the circumferential main groove 2a. Further, the shallow groove 8 extends toward the other side in the tire circumferential direction from the outer side to the inner side in the tire width direction. On the other hand, unlike the above-described embodiment, in the tire of another embodiment, one of the first widthwise grooves forming a pair has a first portion extending from the inner side to the outer side in the tire width direction toward one side in the tire circumferential direction, and one of the second widthwise grooves forming a pair extends from the inner side to the outer side in the tire width direction toward the other side in the tire circumferential direction, and the outer end in the tire width direction of one of the second widthwise grooves forming a pair is located more outward in the tire width direction than the outer end in the tire width direction of one of the first widthwise grooves forming a pair.

[0052] Even in the tire of another embodiment, first, a plurality of first widthwise grooves extending in the tire width direction and having one end terminated within the outermost land portion at the time of vehicle mounting, which is the outermost land portion in the tire width direction on the outer side when the tire is mounted on the vehicle, and a plurality of second widthwise grooves extending in the tire width direction and having at least one end (both ends may be acceptable) terminated within the outermost land portion at the time of vehicle mounting are provided. Therefore, the rigidity against the input in the width direction (the rigidity against the shear deformation due to the input from the outer side to the inner side in the width direction during the vehicle turning travel) can be increased to improve the grip performance. Also, in the pneumatic tire of another embodiment, one of the first widthwise grooves forming a pair has a first portion extending from the inner side to the outer side in the tire width direction toward one side in the tire circumferential direction, and one of the second widthwise grooves forming a pair extends from the inner side to the outer side in the tire width direction toward the other side in the tire circumferential direction. As a result, there are always two types of widthwise grooves with extending directions (the inclination directions in the tire circumferential direction with respect to the tire width direction are opposite to each other) for the input from various directions. Therefore, the problem that the land portion is likely to be deformed with respect to the input from a specific direction can be solved, and the grip performance can be improved. Furthermore, according to such a configuration, since the first portion and the second widthwise grooves are spaced apart from each other by a larger distance in the tire circumferential direction toward the inner side in the tire width direction, a larger area of the land portion can be ensured at the inner side in the tire width direction, and the grip performance can be improved. On the one hand, considering only the direction of the inclination, in the first part and the second widthwise groove, the circumferential separation distance between them becomes smaller toward the outer side in the tire width direction. However, in the pneumatic tire of other embodiments, since the outer end in the tire width direction of one of the second widthwise grooves forming a pair is located further outward in the tire width direction than the outer end in the tire width direction of one of the first widthwise grooves forming a pair, an area where the first widthwise groove and the second widthwise groove approach each other in the tire circumferential direction is not generated as much as possible. Thus, even on the outer side in the tire width direction, a large land area can be ensured, and the grip performance can be improved. As described above, the grip performance can also be improved by the pneumatic tire of other embodiments.

[0053] Also, the tire of other embodiments further includes a shallow groove 8 having one end communicating with the other end of the first widthwise groove 4, and the other end of the shallow groove 8 communicates with the circumferential main groove 2a. Thereby, when the first widthwise groove 4 is located within the ground contact surface, the shallow groove 8 functions as an air escape path, so that the generation of the above-mentioned pattern noise can be suppressed. Furthermore, the drainage performance can be further improved by the drainage of the shallow groove 8 itself and the effective drainage due to the communication between the circumferential main groove 2b and the first widthwise groove 4 by the shallow groove 8. Also, since the groove depth of such a shallow groove 8 is shallower than the groove depth of the first widthwise groove 4, a decrease in the rigidity of the land portion can also be suppressed. Note that the shallow groove 8 may disappear during wear progress. However, during wear progress, the groove depth of the first widthwise groove 4 also becomes shallower, so that the possible pumping noise is also reduced.

[0054] In other embodiments, the groove depth (maximum depth) of the shallow groove 8 is preferably 1.0 mm or more and 2.5 mm or less. By setting it to 1.0 mm or more, the drainage performance can be further improved. On the other hand, by setting it to 2.5 mm or less, a decrease in the rigidity of the outermost land portion 3a when the vehicle is mounted can be suppressed. The groove width (opening width) of the shallow groove 8 is preferably 3.0 to 10.0 mm. By setting it to 3.0 mm or more, the drainage performance can be further improved. On the other hand, by setting it to 10.0 mm or less, a decrease in the rigidity of the outermost land portion 3a when the vehicle is mounted can be suppressed.

[0055] In other embodiments, the shallow groove 8 preferably extends while being inclined at an inclination angle of 40 to 60° with respect to the tire circumferential direction. By setting it to 40° or more, a decrease in the rigidity of the local land portion due to the formation of an acute angle portion can be suppressed. On the other hand, by setting it to 60° or less, the drainage performance can be further improved.

[0056] In other embodiments, the shallow groove 8 preferably communicates with the end portion on one side in the tire circumferential direction (the kicking-out side in this example) of the first widthwise groove 4 (the second portion 42 in the illustrated example). This is because water that has entered the first widthwise groove 4 can be drained to the circumferential main groove 2b via the shallow groove 8, promoting the drainage performance and further improving it.

[0057] In other embodiments as well, the first widthwise groove 4, the second widthwise groove 5, and the shallow groove 8 having the above-described configuration are preferably provided only on the outermost land portion 3a when the vehicle is mounted.

[0058] Here, in other embodiments, the second widthwise groove preferably communicates with the outer tread end when the vehicle is mounted. This is because the drainage performance can be further improved.

[0059] Also, in other embodiments, one first widthwise groove that forms a pair and one other widthwise groove that forms a pair preferably have an overlapping portion when projected in the tire circumferential direction. This is because it becomes easier to ensure a sufficient extension length of the widthwise groove even when considering the arrangement relationship with other grooves.

[0060] In other embodiments, one first widthwise groove further has a second portion extending from the inner end in the tire width direction of the first portion toward one side in the tire circumferential direction, and at least a part of the first portion or at least a part of the second portion preferably has a chamfered portion at the opening to the tread surface. This is because it is possible to further improve the drainage performance when new while suppressing a decrease in rigidity as much as possible.

[0061] In other embodiments, in the reference state, the inclination angle of the tapered surface of the chamfered portion of the second portion with respect to the tire radial direction is preferably larger than the inclination angle of the tapered surface of the chamfered portion of the first portion with respect to the tire radial direction. This is because it is possible to further improve the drainage performance when new while suppressing a decrease in rigidity as much as possible.

[0062] In other embodiments, it is preferable that the inner land portion on the inner side when mounted on a vehicle has only two circumferential main grooves. Thereby, it is possible to ensure good balance between drainage performance and the rigidity of the land portion.

[0063] Regarding the dimensions and inclination angles of the first widthwise groove (first portion, second portion) and the second widthwise groove in other embodiments, except for the direction of the inclination toward the tire circumferential direction with respect to the tire width direction, they can be the same as those in the above embodiments. Similarly, the overlapping width in the tire width direction of the first widthwise groove and the second widthwise groove, and the separation distance in the tire width direction between the outer ends can also be the same as those in the above embodiments.

[0064] Next, the case of providing a communication device in a tire will be described. FIG. 2 is a diagram for explaining an arrangement example of the communication device. As shown in FIG. 2, this tire may include an RF tag as the communication device 91. The RF tag includes an IC chip and an antenna. The RF tag may be arranged, for example, sandwiched between a plurality of like or different members constituting the tire. By doing so, it is easy to attach the RF tag during tire production, and the productivity of the tire provided with the RF tag can be improved. In this example, the RF tag may be arranged, for example, sandwiched between a bead filler and another member adjacent to the bead filler. The RF tag may be embedded in any member constituting the tire. By doing so, compared with the case of being arranged sandwiched between a plurality of members constituting the tire, the load applied to the RF tag can be reduced. Thereby, the durability of the RF tag can be improved. In this example, the RF tag may be embedded in a rubber member such as tread rubber or side rubber, for example. The RF tag is preferably not arranged at a position that becomes the boundary between members with different rigidities in the peripheral length direction, which is the direction along the outer surface of the tire in a cross-sectional view in the tire width direction. By doing so, the RF tag is not arranged at a position where distortion is likely to concentrate due to the rigidity step. Therefore, the load applied to the RF tag can be reduced. Thereby, the durability of the RF tag can be improved. In this example, the RF tag is preferably not arranged, for example, at the boundary between the end of the carcass and a member (such as side rubber) adjacent to the end of the carcass in a cross-sectional view in the tire width direction. The number of RF tags is not particularly limited. The tire may include only one RF tag or two or more RF tags. Here, as an example of the communication device, an RF tag is illustrated and described, but a communication device different from the RF tag may also be used.

[0065] The RF tag may be arranged, for example, in the tread portion of the tire. By doing so, the RF tag will not be damaged by a side cut of the tire. The RF tag may be arranged, for example, at the center of the tread in the tire width direction. The center of the tread is a position where deflection is less likely to concentrate in the tread portion. By doing so, the load applied to the RF tag can be reduced. Thereby, the durability of the RF tag can be improved. Also, it is possible to suppress a difference in communication performance with the RF tag from both outer sides of the tire in the tire width direction. In this example, the RF tag may be arranged, for example, within a range of 1 / 2 of the tread width centered on the tire equatorial plane in the tire width direction. The RF tag may be arranged, for example, at the tread end in the tire width direction. When the position of the reader that communicates with the RF tag is predetermined, the RF tag may be arranged, for example, at the tread end on one side closer to this reader. In this example, the RF tag may be arranged, for example, within a range of 1 / 4 of the tread width with the tread end as the outer end in the tire width direction.

[0066] The RF tag may be disposed on the inner cavity side of the tire, for example, from a carcass including one or more carcass plies straddling between bead portions. By doing so, it becomes difficult for the RF tag to be damaged against impacts applied from the outside of the tire or damages such as side cuts and punctures. As an example, the RF tag may be disposed in close contact with the surface on the inner cavity side of the carcass of the tire. As another example, when there is another member on the inner cavity side of the tire from the carcass, the RF tag may be disposed, for example, between the carcass and another member located on the inner cavity side of the tire from this carcass. Examples of another member located on the inner cavity side of the tire from the carcass include, for example, an inner liner forming the inner surface of the tire. As another example, the RF tag may be attached to the inner surface of the tire facing the inner cavity of the tire. By configuring the RF tag to be attached to the inner surface of the tire, it becomes easy to attach the RF tag to the tire and to inspect and replace the RF tag. That is, the attachability and maintainability of the RF tag can be improved. Also, by attaching the RF tag to the inner surface of the tire, it is possible to prevent the RF tag from becoming the core of tire failure as compared with a configuration in which the RF tag is embedded in the tire. Further, when the carcass includes a plurality of carcass plies and there is a position where the plurality of carcass plies are overlapped, the RF tag may be disposed between the overlapped carcass plies.

[0067] The RF tag may be disposed, for example, on the tread portion of the tire, radially outward of the belt including one or more belt plies. As an example, the RF tag may be disposed in close contact with the belt radially outward of the belt in the tire radial direction. Further, as another example, when a reinforcing belt layer is provided, the RF tag may be disposed in close contact with the reinforcing belt layer radially outward of the reinforcing belt layer in the tire radial direction. Further, as another example, the RF tag may be embedded in the tread rubber radially outward of the belt. By disposing the RF tag on the tread portion of the tire radially outward of the belt, communication with the RF tag from the outside of the tire in the tire radial direction is less likely to be obstructed by the belt. Therefore, the communication performance with the RF tag from the outside of the tire in the tire radial direction can be improved. Further, the RF tag may be disposed, for example, on the tread portion of the tire radially inward of the belt. By doing so, since the outside of the RF tag in the tire radial direction is covered by the belt, the RF tag is less likely to be damaged by impacts from the tread surface or punctures. As an example, the RF tag may be disposed on the tread portion of the tire between the belt and the carcass located radially inward of the belt in the tire radial direction. Further, when the belt includes a plurality of belt plies, the RF tag may be disposed on the tread portion of the tire between any two belt plies. By doing so, since the outside of the RF tag in the tire radial direction is covered by one or more belt plies, the RF tag is less likely to be damaged by impacts from the tread surface or punctures.

[0068] The RF tag may be disposed, for example, at the position of the sidewall portion or the bead portion of the tire. The RF tag may be disposed, for example, at the sidewall portion or the bead portion on one side closer to the reader capable of communicating with the RF tag. By doing so, the communication performance between the RF tag and the reader can be enhanced. As an example, the RF tag may be disposed between the carcass and the side rubber, or between the tread rubber and the side rubber. The RF tag may be disposed, for example, in the tire radial direction between the position where the tire has its maximum width and the position of the tread surface. By doing so, compared with the configuration in which the RF tag is disposed inside the tire in the tire radial direction from the position where the tire has its maximum width, the communication performance between the RF tag and the outside of the tire in the tire radial direction can be enhanced. The RF tag may be disposed, for example, inside the tire in the tire radial direction from the position where the tire has its maximum width. By doing so, the RF tag is disposed near the bead portion with high rigidity. Therefore, the load applied to the RF tag can be reduced. Thereby, the durability of the RF tag can be improved. As an example, the RF tag may be disposed at a position adjacent to the bead core in the tire radial direction or the tire width direction. Distortion is unlikely to concentrate near the bead core. Therefore, the load applied to the RF tag can be reduced. Thereby, the durability of the RF tag can be improved. In particular, it is preferable that the RF tag is disposed inside the tire in the tire radial direction from the position where the tire has its maximum width and outside the tire in the tire radial direction from the bead core of the bead portion. By doing so, the durability of the RF tag can be improved, and the communication between the RF tag and the reader is less likely to be obstructed by the bead core, and the communication performance of the RF tag can be enhanced. Further, when the side rubber is composed of a plurality of rubber members of the same or different types adjacent to each other in the tire radial direction, the RF tag may be disposed sandwiched between the plurality of rubber members constituting the side rubber.

[0069] The RF tag may be disposed sandwiched between a bead filler and a member adjacent to the bead filler. By doing so, the RF tag can be disposed at a position where it is difficult for distortion to concentrate due to the arrangement of the bead filler. Therefore, the load applied to the RF tag can be reduced. Thereby, the durability of the RF tag can be improved. The RF tag may be disposed, for example, sandwiched between a bead filler and a carcass. The portion of the carcass that sandwiches the RF tag together with the bead filler may be located outside the bead filler in the tire width direction or inside the bead filler in the tire width direction. When the portion of the carcass that sandwiches the RF tag together with the bead filler is located outside the bead filler in the tire width direction, the load applied to the RF tag can be further reduced by the impact or damage from the outside of the tire in the tire width direction. Thereby, the durability of the RF tag can be further improved. Further, the bead filler may include a portion disposed adjacent to the side rubber. In such a case, the RF tag may be disposed sandwiched between the bead filler and the side rubber. Furthermore, the bead filler may include a portion disposed adjacent to the rubber chafer. In such a case, the RF tag may be disposed sandwiched between the bead filler and the rubber chafer.

[0070] The RF tag may be disposed, for example, sandwiched between a rubber chafer and a side rubber. By doing so, the RF tag can be disposed at a position where it is difficult for distortion to concentrate due to the arrangement of the rubber chafer. Therefore, the load applied to the RF tag can be reduced. Thereby, the durability of the RF tag can be improved. The RF tag may be disposed, for example, sandwiched between a rubber chafer and a carcass. By doing so, the load applied to the RF tag can be reduced by the impact or damage applied from the rim. Therefore, the durability of the RF tag can be improved.

[0071] The RF tag may be disposed sandwiched between a wire chafer and another member adjacent to the inside or outside in the tire width direction of this wire chafer. By doing so, when the tire deforms, the position of the RF tag becomes difficult to fluctuate. Therefore, the load applied to the RF tag when the tire deforms can be reduced. Thereby, the durability of the RF tag can be improved. Another member adjacent to the inside or outside of the wire chafer in the tire width direction may be, for example, a rubber member such as a rubber chafer. Further, another member adjacent to the inside or outside of the wire chafer in the tire width direction may be, for example, a carcass.

[0072] A belt reinforcing layer may be further provided on the outer side in the radial direction of the belt. For example, the belt reinforcing layer may be formed by continuously winding a cord made of polyethylene terephthalate in a spiral shape in the tire circumferential direction. Here, the cord is subjected to an adhesive treatment by applying a tension of 6.9×10 -2 N / tex or more, and the elastic modulus at a load of 29.4 N measured at 160 °C may be 2.5 mN / dtex·% or more. Further, the belt reinforcing layer may be arranged to cover the entire belt or may be arranged to cover only both ends of the belt. Further, the winding density per unit width of the belt reinforcing layer may vary depending on the width direction position. By doing so, load noise and flat spots can be reduced without degrading high-speed durability.

Explanation of Signs

[0073] 1: Tread surface, 2, 2a, 2b: Circumferential main grooves, 3: Land portion, 3a: Outermost land portion when mounted on a vehicle, 3b: Inner land portion when mounted on a vehicle, 3b1: Outer land portion of the inner land portion when mounted on a vehicle, 3b2: Inner land portion of the inner land portion when mounted on a vehicle, 4: First width direction groove, 41: First portion, 42: Second portion, 5: Second width direction groove, 6: Third widthwise groove, 7: Notch, 8: Shallow groove, 9: Fourth widthwise groove, 91: Communication device, CL: Tire equatorial plane, TE: Tread edge

Claims

1. A pneumatic tire having one or more circumferential main grooves extending in the tire circumferential direction on a tread surface, having a plurality of land portions partitioned between the circumferential main grooves and the tread ends or between the circumferential main grooves, on the outermost land portion in the tire width direction on the outside when the tire is mounted on a vehicle, i.e., the outermost land portion when the tire is mounted on the vehicle, having a plurality of first width direction grooves extending in the tire width direction and having one end terminated within the outermost land portion when the tire is mounted on the vehicle, and a plurality of second width direction grooves extending in the tire width direction and having at least one end terminated within the outermost land portion when the tire is mounted on the vehicle, wherein the first width direction grooves and the second width direction grooves are alternately arranged in the tire circumferential direction while being spaced apart from each other in the tire circumferential direction, one of the first width direction grooves and one of the second width direction grooves adjacent to the one first width direction groove on one side in the tire circumferential direction form a pair, the one first width direction groove constituting the pair has a first portion extending in one side in the tire circumferential direction from the outside to the inside in the tire width direction, the one second width direction groove constituting the pair extends in the other side in the tire circumferential direction from the outside to the inside in the tire width direction, the inner end in the tire width direction of the one second width direction groove constituting the pair is located outside in the tire width direction than the inner end in the tire width direction of the one first width direction groove constituting the pair, further comprising a shallow groove having one end communicating with the other end of the first width direction groove, wherein the groove depth of the shallow groove is shallower than the groove depth of the first width direction groove, and the other end of the shallow groove communicates with the circumferential main groove, characterized in that it is a pneumatic tire.

2. The pneumatic tire according to claim 1, wherein the groove depth of the shallow groove is 2.5 mm or less.

3. The pneumatic tire according to claim 1 or 2, wherein the shallow groove extends obliquely at an inclination angle of 40 to 60° with respect to the tire circumferential direction.

4. The pneumatic tire according to claim 1 or 2, wherein the shallow groove communicates with an end portion on one side in the tire circumferential direction of the first width direction groove.

5. The pneumatic tire according to claim 1 or 2, wherein the first width direction grooves, the second width direction grooves, and the shallow groove are provided only in the outermost land portion when the tire is mounted on the vehicle.

6. The pneumatic tire according to claim 1 or 2, wherein the second width direction groove communicates with the tread end on the outside when the tire is mounted on the vehicle.

7. A pneumatic tire having one or more circumferential main grooves extending in the tire circumferential direction on a tread surface, It has a plurality of land portions partitioned between the circumferential main grooves and the tread ends or between the circumferential main grooves. On the outermost land portion in the tire width direction on the outer side when the tire is mounted on a vehicle, which is the outermost land portion when the vehicle is mounted, there are a plurality of first width direction grooves extending in the tire width direction and having one end terminating within the outermost land portion when the vehicle is mounted, and a plurality of second width direction grooves extending in the tire width direction and having at least one end terminating within the outermost land portion when the vehicle is mounted. The first width direction grooves and the second width direction grooves are alternately arranged in the tire circumferential direction while being spaced apart from each other in the tire circumferential direction. One of the first width direction grooves and one of the second width direction grooves adjacent to the one first width direction groove on one side in the tire circumferential direction form a pair. The one first width direction groove constituting the pair has a first portion extending in one side in the tire circumferential direction from the inner side to the outer side in the tire width direction. The one second width direction groove constituting the pair extends in the other side in the tire circumferential direction from the inner side to the outer side in the tire width direction. The outer end in the tire width direction of the one second width direction groove constituting the pair is located outside in the tire width direction than the outer end in the tire width direction of the one first width direction groove constituting the pair. It further includes a shallow groove having one end communicating with the other end of the first width direction groove. The groove depth of the shallow groove is shallower than the groove depth of the first width direction groove. An air-filled tire, wherein the other end of the shallow groove communicates with the circumferential main groove.

8. The air-filled tire according to claim 7, wherein the groove depth of the shallow groove is 2.5 mm or less.

9. The air-filled tire according to claim 7 or 8, wherein the shallow groove extends obliquely at an inclination angle of 40 to 60° with respect to the tire circumferential direction.

10. The air-filled tire according to claim 7 or 8, wherein the shallow groove communicates with an end portion on one side in the tire circumferential direction of the first width direction groove.

11. The air-filled tire according to claim 7 or 8, wherein the first width direction grooves, the second width direction grooves, and the shallow groove are provided only on the outermost land portion when the vehicle is mounted.

12. The air-filled tire according to claim 7 or 8, wherein the second width direction groove communicates with the tread end on the outer side when the vehicle is mounted.

Images