tire

Abstract

To improve disturbance converging performance and abrasion resistance, while maintaining wet grip performance.SOLUTION: A pneumatic tire 1 comprises first inclined grooves 21, second inclined grooves 22 and third inclined grooves 23 inclined with respect to a tier circumferential direction, at one side in a tire width direction across a tire equatorial plane CL corresponding to a developed width TDW of a tread part 2. The first inclined grooves 21 and the second inclined grooves 22 constitute circumferential grooves 20 communicated with each other in the tire circumferential direction. The circumferential grooves 20 are arranged across a position corresponding to 50% of the developed width TDW at the one side without being arranged across the tire equatorial plane CL, and the third inclined grooves 23 are arranged across the position corresponding to 50% of the developed width TDW at the one side, outside in the tire width direction of the circumferential grooves 20 to open to an outermost end 2Aa in the tire width direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This invention relates to a tire.

Background Art

[0002] For example, Patent Document 1 discloses a tire including, in a tread portion, two circumferential grooves that extend in a zigzag shape continuously in the circumferential direction of the tire on both sides of the tire equator, and a plurality of inclined grooves that extend inclined with respect to the tire width direction on the outer side in the tire width direction of the circumferential grooves.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, in a motorcycle tire, there is a method of increasing grooves to improve drainage performance and wet grip (grip performance on a wet road surface). However, as the groove area increases, the tread rigidity of the contact surface decreases, resulting in deterioration of wear resistance performance and disturbance convergence performance, which leads to vibration of the vehicle body.

[0005] An object of this invention is to provide a tire capable of improving disturbance convergence performance and wear resistance performance while maintaining wet grip performance.

Means for Solving the Problems

[0006] To achieve the above object, a tire according to one aspect of the present invention has a first inclined groove, a second inclined groove, and a third inclined groove that are inclined with respect to the tire circumferential direction on one side in the tire width direction with the tire equatorial plane of the developed width of the tread portion as a boundary. The first inclined groove and the second inclined groove constitute a circumferential groove that is alternately communicated in the tire circumferential direction, and the circumferential groove is arranged across the 50% position of the developed width on one side without straddling the tire equatorial plane. The third inclined groove is arranged across the 50% position of the developed width on one side outside the circumferential groove in the tire width direction and opens at the outermost end in the tire width direction.

Advantages of the Invention

[0007] According to this invention, it is possible to improve the disturbance convergence performance and wear resistance while maintaining the wet grip performance.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

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MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited by this embodiment. In addition, the components of this embodiment include those that can be replaced and are self-evidently replaceable while maintaining the identity of the invention. Further, a plurality of modifications described in this embodiment can be arbitrarily combined within the scope self-evident to those skilled in the art.

[0010] In the following description, the tire radial direction refers to the direction orthogonal to the tire rotation axis (not shown) which is the rotation axis of the pneumatic tires 1, 1' of the embodiment. The inner side in the tire radial direction refers to the side facing the tire rotation axis in the tire radial direction, and the outer side in the tire radial direction refers to the side away from the tire rotation axis in the tire radial direction. Further, the tire circumferential direction refers to the circumferential direction around the tire rotation axis as the central axis. Also, the tire width direction refers to the direction parallel to the tire rotation axis. The inner side in the tire width direction refers to the side facing the tire equatorial plane (tire equator line) CL in the tire width direction, and the outer side in the tire width direction refers to the side away from the tire equatorial plane CL in the tire width direction. The tire equatorial plane CL is a plane that is orthogonal to the tire rotation axis and passes through the center of the tire width of the pneumatic tires 1, 1'. The tire equatorial plane CL coincides with the tire width direction center line which is the central position in the tire width direction of the pneumatic tires 1, 1'. The tire equator line refers to a line on the tire equatorial plane CL and along the tire circumferential direction of the pneumatic tires 1, 1'. Also, the cross-section in the tire meridian direction (meridian sectional view) refers to the cross-section when the tire is cut by a plane including the tire rotation axis.

[0011] FIG. 1 is a meridian sectional view of the pneumatic tires according to the embodiment and the reference embodiment. Here, as an example, a tire mounted on a two-wheeled vehicle will be described.

[0012] As shown in FIG. 1, the pneumatic tires 1, 1' have a tread portion 2, side portions 3 on both sides of the tread portion 2, and bead portions 4 on the inner side in the tire radial direction of each side portion 3. Further, the pneumatic tires 1, 1' have a carcass layer 5.

[0013] The tread portion 2 is made of a rubber material, is exposed on the outermost side in the tire radial direction of the pneumatic tires 1, 1', and its surface forms the contour of the pneumatic tires 1, 1'. A tread surface 2A is formed on the outer peripheral surface of the tread portion 2, that is, the tread surface that contacts the road surface during running.

[0014] The side portion 3 has a rubber material continuous on both sides in the tire width direction of the tread portion 2 and is a portion exposed to the outside in the tire width direction in the pneumatic tires 1, 1'. Further, the bead portion 4 has a rubber material continuous on the inner side in the tire diameter direction of the side portion 3 and is a portion that engages with the rim 7. The bead portion 4 has a bead core 4A and a bead filler 4B. The bead core 4A is formed by winding a bead wire, which is a steel wire, in a ring shape. The bead filler 4B is a rubber material disposed in a space formed by folding back the tire width direction end portions of the carcass layer 5 at the position of the bead core 4A.

[0015] At least two carcass layers 5 are provided by being laminated inside and outside the tire. In the present embodiment, a form having two carcass layers 5A, 5B will be illustrated and described. Each of the carcass layers 5A, 5B has a folded-back portion where the end portions 5Aa, 5Ba in the tire width direction are folded back from the inner side in the tire width direction to the outer side in the tire width direction by a pair of bead cores 4A, and is wound in a toroidal shape in the tire circumferential direction to constitute the skeleton of the tire. Each of the carcass layers 5A, 5B is formed by coating carcass cords arranged in a plurality in parallel in the tire circumferential direction with a coating rubber and having a predetermined angle with respect to the tire circumferential direction. Further, each of the carcass layers 5A, 5B has a bias structure in which the carcass cords of each other are arranged to intersect. In the case of a configuration of three or more carcass layers 5, the carcass cords of each other that are overlapped by lamination are arranged to intersect. As the carcass cord, for example, a reinforcing cord of organic fiber such as nylon is used.

[0016] Note that the pneumatic tires 1, 1' shown in FIG. 1 are configured as tubeless tires in which no tube is arranged. In the case of a tubeless tire, an inner liner layer 6 is provided on the tire inner surface, which is the inner circumferential surface of the carcass layer 5, and air is filled inside this inner liner layer 6 to suppress the permeation of air molecules to the outside of the tire. Further, the pneumatic tires 1, 1' of the present embodiment may be configured as tubed tires in which a tube is arranged inside the carcass layer 5, and air is filled in the tube.

[0017] The pneumatic tires 1 and 1' of the present embodiment are defined as follows in a state of being mounted on a rim (regular rim) 7 and filled with a regular internal pressure as shown in FIG. 1 in a non-loaded state.

[0018] Here, the regular rim is the "Standard Rim" defined by JATMA, the "Design Rim" defined by TRA, or the "Measuring Rim" defined by ETRTO. The regular internal pressure is the "Maximum Air Pressure" defined by JATMA, the maximum value described in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" defined by TRA, or the "INFLATION PRESSURES" defined by ETRTO. The regular load is the "Maximum Load Capacity" defined by JATMA, the maximum value described in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" defined by TRA, or the "LOAD CAPACITY" defined by ETRTO.

[0019] [Embodiment] Hereinafter, the pneumatic tire 1 of the embodiment will be described. FIG. 2 is a developed view of the tread portion of the pneumatic tire according to the embodiment. FIG. 3 is an enlarged developed view of the tread portion of the pneumatic tire according to the embodiment. FIG. 4 is an enlarged developed view of the tread portion of the pneumatic tire according to the embodiment. FIG. 5 is an enlarged developed view of the tread portion of the pneumatic tire according to the embodiment.

[0020] The pneumatic tire 1 of the present embodiment is particularly suitable for a tire mounted on a rear tire (rear wheel) of a two-wheeled vehicle. Each groove is formed in the tread surface 2A of this pneumatic tire 1.

[0021] As shown in FIG. 2, the pneumatic tire 1 has a first inclined groove 21, a second inclined groove 22, and a third inclined groove 23 on the tread surface 2A of the tread portion 2 on both sides in the tire width direction with the tire equatorial plane CL of the developed width TDW of the tread portion 2 as a boundary. Here, the developed width TDW is the dimension obtained by developing between the outermost ends 2Aa on both sides in the tire width direction of the tread surface 2A (tread portion 2). In the pneumatic tire 1 of the embodiment, the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are respectively provided on both sides in the tire width direction with the tire equatorial plane CL as a boundary and are arranged in pairs. Therefore, hereinafter, one side in the tire width direction with the tire equatorial plane CL of the developed width TDW of the tread portion 2 as a boundary will be described.

[0022] The first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are provided inclined with respect to the tire circumferential direction. The first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are provided inclined in the same direction with respect to the tire circumferential direction, and the directions of inclination are the same.

[0023] Both ends 21a, 21b (see FIG. 3) of the first inclined groove 21 terminate within the tread surface 2A of the tread portion 2. Both ends 22a, 22b (see FIG. 3) of the second inclined groove 22 terminate within the tread surface 2A of the tread portion 2. The first inclined groove 21 and the second inclined groove 22 communicate alternately in the tire circumferential direction and constitute a circumferential groove 20 that continuously extends in a zigzag shape in the tire circumferential direction. The circumferential groove 20 is arranged on the inner side in the tire width direction closer to the tire equatorial plane CL on one side in the tire width direction with the tire equatorial plane CL of the developed width TDW of the tread portion 2 as a boundary. The circumferential groove 20 does not straddle the tire equatorial plane CL. "Does not straddle" means that it includes contacting the tire equatorial plane CL, which is a reference line extending in the tire circumferential direction, but the groove does not cross the tire equatorial plane CL. Further, the circumferential groove 20 is arranged so as to straddle a reference line C that is at the position of 50% (1 / 4 TDW) of the developed width TDW on one side in the tire width direction. "Straddle" means crossing a reference line C extending in the tire circumferential direction. The groove depth of the first inclined groove 21 is preferably in the range of 3 mm or more and 8 mm or less. The groove depth of the second inclined groove 22 is preferably in the range of 1 mm or more and 8 mm or less.

[0024] The third inclined groove 23 is arranged independently without communicating with the circumferential groove 20. The third inclined groove 23 is arranged on the outer side in the tire width direction away from the tire equatorial plane CL than the circumferential groove 20. The third inclined groove 23 is arranged between the first inclined groove 21 and the second inclined groove 22 forming the circumferential groove 20 in the tire circumferential direction. The outer end in the tire width direction of the third inclined groove 23 opens to the outermost end 2Aa in the tire width direction of the tread surface 2A, and the inner end in the tire width direction terminates within the tread surface 2A of the tread portion 2. Further, the third inclined groove 23 is arranged across the reference line C which is at the position of 50% (1 / 4 TDW) of the unfolded width TDW on one side in the tire width direction. Note that the groove depth of the third inclined groove 23 is preferably in the range of 2 mm or more and 8 mm or less.

[0025] As described above, in this pneumatic tire 1, the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are respectively provided on both sides in the tire width direction with the tire equatorial plane CL as a boundary, and are arranged symmetrically. Specifically, in one side in the tire width direction with the tire equatorial plane CL as a boundary, one first inclined groove 21, one second inclined groove 22, and one third inclined groove 23 are arranged at one pitch P in the tire circumferential direction. That is, in one side in the tire width direction with the tire equatorial plane CL as a boundary, a part of the circumferential groove 20 formed by one first inclined groove 21 and one second inclined groove 22, and one third inclined groove 23 arranged between these first inclined groove 21 and second inclined groove 22 in the tire circumferential direction are arranged at one pitch P in the tire circumferential direction. And on both sides in the tire width direction with the tire equatorial plane CL as a boundary, one pitch P formed by one first inclined groove 21, one second inclined groove 22, and one third inclined groove 23 is arranged with a shift in the tire circumferential direction in the range of 30% or more and 80% or less between one side and the other side when one pitch P is taken as 100%.

[0026] The pneumatic tire 1 having the above configuration has, on one side in the tire width direction with respect to the tire equatorial plane CL of the tread width TDW, a first inclined groove 21, a second inclined groove 22, and a third inclined groove 23 that are inclined with respect to the tire circumferential direction. The first inclined groove 21 and the second inclined groove 22 constitute a circumferential groove 20 that is alternately communicated in the tire circumferential direction, and the circumferential groove 20 is arranged across the 50% position of the one-side tread width TDW without straddling the tire equatorial plane CL. The third inclined groove 23 is arranged to straddle the 50% position of the one-side tread width TDW outside the tire width direction of the circumferential groove 20 and open to the outermost end 2Aa in the tire width direction.

[0027] According to this pneumatic tire 1, the wet grip performance is maintained by draining water in the tire circumferential direction and the tire width direction during straight running and turning (banking in the case of a two-wheeled vehicle) by the inclined first inclined groove 21, second inclined groove 22, and third inclined groove 23. Further, according to this pneumatic tire 1, since the circumferential groove 20 is not in the central region of the tread width TDW without straddling the tire equatorial plane CL, a decrease in rigidity in the central region of the tread width TDW can be prevented, and the disturbance convergence performance and the wear resistance performance can be improved.

[0028] As shown in FIG. 3, for the pneumatic tire 1 of the embodiment, the angles of the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 that are inclined in the same direction with respect to the tire circumferential direction are defined.

[0029] The first inclined groove 21 has an angle θ1IN with respect to the tire circumferential direction at the inner end 21a in the tire width direction and an angle θ1OUT with respect to the tire circumferential direction at the outer end 21b in the tire width direction. Each of the angles θ1IN and θ1OUT of the first inclined groove 21 is an angle on the side of 90° or less with respect to the tire circumferential direction at the position where the center line 21c passing through the center of the groove width of the first inclined groove 21 along the extending direction of the first inclined groove 21 intersects with the center line 22c passing through the center of the groove width of the second inclined groove 22 along the extending direction of the second inclined groove 22. The first inclined groove 21 may be formed as a straight line, but in the embodiment, it is formed to be curved. When the first inclined groove 21 is a straight line, the angles θ1IN and θ1OUT of the first inclined groove 21 are the angles formed by the center line 21c and the tire circumferential direction at the intersection point because the center line 21c is a straight line. On the other hand, when the first inclined groove 21 is curved, the angles θ1IN and θ1OUT of the first inclined groove 21 are the angles formed by the tangent line of the center line 21c and the tire circumferential direction at the intersection point because the center line 21c is curved. In the pneumatic tire 1 of the embodiment, it is desirable that the angle θ1IN of the inner end 21a of the first inclined groove 21 is in the range of 5° or more and 15° or less. Also, in the pneumatic tire 1 of the embodiment, the angle θ1OUT of the outer end 21b of the first inclined groove 21 is equal to or greater than the angle θ1IN, and it is desirable that the angle θ1OUT is larger than the angle θ1IN.

[0030] The second inclined groove 22 has an angle θ2IN with respect to the tire circumferential direction at the inner end 22a in the tire width direction and an angle θ2OUT with respect to the tire circumferential direction at the outer end 22b in the tire width direction. Each of the angles θ2IN and θ2OUT of the second inclined groove 22 is an angle on the side of 90° or less with respect to the tire circumferential direction at the position where the center line 21c of the first inclined groove 21 intersects the center line 22c passing through the center of the groove width of the second inclined groove 22 along the extending direction of the second inclined groove 22. The second inclined groove 22 may be formed to be curved, but in the embodiment, it is formed as a straight line. When the second inclined groove 22 is a straight line, the angles θ2IN and θ2OUT of the second inclined groove 22 are the angles formed by the center line 22c and the tire circumferential direction at the above intersection because the center line 22c is a straight line. On the other hand, when the second inclined groove 22 is curved, the angles θ2IN and θ2OUT of the second inclined groove 22 are the angles formed by the tangent line of the center line 22c and the tire circumferential direction at the above intersection because the center line 22c is curved. In the pneumatic tire 1 of the embodiment, the angle θ2IN at the inner end 22a of the second inclined groove 22 is equal to or greater than the angle θ1IN at the inner end 21a of the first inclined groove 21, and preferably 45° or more and 90° or less. Further, in the pneumatic tire 1 of the embodiment, the angle θ2OUT at the outer end 22b of the second inclined groove 22 is equal to or greater than the angle θ2IN, and preferably the angle θ2IN + 15°.

[0031] The third inclined groove 23 has an angle θ3IN with respect to the tire circumferential direction at the inner end 23a in the tire width direction and an angle θ3OUT with respect to the tire circumferential direction at the outer end 23b in the tire width direction. Each angle θ3IN of the third inclined groove 23 is an angle on the side of 90° or less with respect to the tire circumferential direction at the end position of the third inclined groove 23 on the center line 23c passing through the center of the groove width of the third inclined groove 23 along the extending direction of the third inclined groove 23. The angle θ3OUT of the third inclined groove 23 is an angle on the side of 90° or less with respect to the tire circumferential direction at the position where the outer end 23b of the third inclined groove 23 opens on the center line 23c of the third inclined groove 23. When a chamfer 23ba is provided at the opening edge of the outer end 23b of the third inclined groove 23, it is the angle on the side of 90° or less with respect to the tire circumferential direction at the inflection point between the chamfer 23ba and the opening edge and at the position passing through the minimum groove width. The third inclined groove 23 may be formed as a straight line, but in the embodiment, it is formed to be curved. When the third inclined groove 23 is a straight line, the angle θ3IN and the angle θ3OUT of the third inclined groove 23 are the angles formed by the center line 23c and the tire circumferential direction because the center line 23c is a straight line. On the other hand, when the third inclined groove 23 is curved, the angle θ3IN and the angle θ3OUT of the third inclined groove 23 are the angles formed by the tangent line of the center line 23c and the tire circumferential direction because the center line 23c is curved. In the pneumatic tire 1 of the embodiment, it is desirable that the angle θ3IN of the inner end 23a of the third inclined groove 23 is in the range of 30° or more and 40° or less. Also, in the pneumatic tire 1 of the embodiment, it is desirable that the angle θ3OUT of the outer end 23b of the third inclined groove 23 is equal to or greater than the angle θ3IN and is greater than the angle θ3IN.

[0032] In the pneumatic tire 1 configured as described above, the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are inclined in the same direction with respect to the tire circumferential direction, and the angles with respect to the tire circumferential direction satisfy the relationships of θ1IN≦θ2IN, θ1IN≦θ3IN, and also satisfy the relationships of θ1IN≦θ1OUT, θ2IN≦θ2OUT, θ3IN≦θ3OUT.

[0033] According to this pneumatic tire 1, the wet grip performance is maintained by draining water in the tire circumferential direction and the tire width direction both during straight running and turning by means of the inclined first inclined groove 21, second inclined groove 22, and third inclined groove 23. Further, according to this pneumatic tire 1, the rigidity balance between the tire circumferential direction and the tire width direction can be adjusted by the above relationship of the angles of the inclined first inclined groove 21, second inclined groove 22, and third inclined groove 23, and the disturbance convergence performance and the wear resistance performance can be improved.

[0034] Further, in the pneumatic tire 1 having the above configuration, the angle θ2IN (θ2OUT) of the second inclined groove 22 with respect to the tire circumferential direction is different from the angle θ1IN (θ1OUT) of the first inclined groove 21 with respect to the tire circumferential direction and the angle θ3IN (θ3OUT) of the third inclined groove 23 with respect to the tire circumferential direction.

[0035] According to this pneumatic tire 1, the wet grip performance is maintained by draining water in the tire width direction during straight running by means of the inclined first inclined groove 21, second inclined groove 22, and third inclined groove 23. Further, according to this pneumatic tire 1, the rigidity balance between the tire circumferential direction and the tire width direction can be adjusted by the above relationship of the angles of the second inclined groove 22 with the first inclined groove 21 and the third inclined groove 23, and the disturbance convergence performance and the wear resistance performance can be improved.

[0036] As shown in FIG. 3, in the pneumatic tire 1 of the embodiment, chamfers are provided at the corner portion of the circumferential groove 20 where the first inclined groove 21 and the second inclined groove 22 communicate and at the end of the third inclined groove 23, respectively.

[0037] The corner portion of the circumferential groove 20 where the first inclined groove 21 and the second inclined groove 22 communicate can be formed with an acute angle as it is, but chamfers 20aa and 20ba are provided so as to cut the corner portion. The chamfer 20aa is provided on both sides of the inner corner and the outer corner of the corner portion of the circumferential groove 20 where the inner end 21a of the first inclined groove 21 and the inner end 22a of the second inclined groove 22 communicate. The chamfer 20aa may be provided on at least one side of the inner corner and the outer corner of the corner portion. The chamfer 20ba is provided on both sides of the inner corner and the outer corner of the corner portion of the circumferential groove 20 where the outer end 21b of the first inclined groove 21 and the outer end 22b of the second inclined groove 22 communicate. The chamfer 20ba may be provided on at least one side of the inner corner and the outer corner of the corner portion. The chamfers 20aa and 20ba are preferably formed as arc surfaces in the embodiment, but may be formed as flat surfaces.

[0038] The inner end 23a and the outer end 23b of the third inclined groove 23 can be formed with an acute angle as they are, but chamfers 23aa and 23ba are provided so as to cut the portion. The chamfer 23aa is provided at the inner end 23a of the third inclined groove 23. The chamfer 23ba is provided at the outer end 23b of the third inclined groove 23 and at both opening edges opening to the outermost end 2Aa in the tire width direction of the tread surface 2A. The chamfers 23aa and 23ba are preferably formed as arc surfaces in the embodiment, but may be formed as flat surfaces.

[0039] The pneumatic tire 1 having the above configuration is characterized in that chamfers 20aa and 20ba are provided on at least one side of the corner portion where the first inclined groove 21 and the second inclined groove 22 communicate.

[0040] According to this pneumatic tire 1, the chamfers 20aa and 20ba at the corner portion where the first inclined groove 21 and the second inclined groove 22 communicate can make the groove width of the corner portion constant, suppress the generation of local land portion changes, suppress the occurrence of uneven wear, and improve the wear resistance performance.

[0041] As shown in FIG. 4, the pneumatic tire 1 of the embodiment defines the relationship of the tire circumferential lengths L1, L2, and L3 of the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23.

[0042] In the pneumatic tire 1, in the first inclined groove 21, the tire circumferential direction length between the inner end 21a and the outer end 21b is defined as L1. In the pneumatic tire 1, in the second inclined groove 22, the tire circumferential direction length between the inner end 22a and the outer end 22b is defined as L2. In the pneumatic tire 1, in the third inclined groove 23, the tire circumferential direction length between the inner end 23a and the outer end 23b is defined as L3.

[0043] In the pneumatic tire 1 having the above configuration, when the tire circumferential direction lengths L2 of the second inclined groove 22 and L3 of the third inclined groove 23 are projected onto the tire equatorial plane CL, they do not overlap with each other.

[0044] According to this pneumatic tire 1, by setting the projections of the second inclined groove 22 and the third inclined groove 23 onto the tire equatorial plane CL not to overlap in the tire circumferential direction, a decrease in the local land portion can be prevented, the occurrence of uneven wear can be suppressed, and the wear resistance performance can be improved.

[0045] Further, in the pneumatic tire 1 having the above configuration, the tire circumferential direction length L1 of the first inclined groove 21, the tire circumferential direction length L2 of the second inclined groove 22, the tire circumferential direction length L3 of the third inclined groove 23, and the tread width TDW satisfy the relationships of L2 < L3 < L1, 0.6×TDW < L1 < TDW, and L3 < 0.5×L1.

[0046] According to this pneumatic tire 1, since the first inclined groove 21 having the longest tire circumferential direction length L1 enters the contact area when in contact with the ground, drainage can be performed from the tire circumferential direction and the tire width direction when in contact with the ground, and the wet grip performance can be maintained. Further, according to this pneumatic tire 1, by making the tire circumferential direction length L3 of the third inclined groove 23 shorter than the tire circumferential direction length L1 of the first inclined groove 21, the contact area of the land portion during turning (banking) can be maintained, and the disturbance convergence performance and the wear resistance performance can be improved.

[0047] As shown in FIG. 5, in the pneumatic tire 1 of the embodiment, the groove widths of the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are defined.

[0048] The first inclined groove 21 has a groove width of W1IN at the inner end 21a in the tire width direction and a groove width of W1OUT at the outer end 21b in the tire width direction. In the pneumatic tire 1 of the embodiment, since a chamfer 20aa is provided at the corner portion of the circumferential groove 20 where the inner end 21a in the tire width direction of the first inclined groove 21 communicates with the second inclined groove 22, the groove width W1IN is the groove width at the inflection point between the chamfer 20aa and the opening edge of the first inclined groove 21 and at the position passing through the minimum groove width. In the pneumatic tire 1 of the embodiment, since a chamfer 20ba is provided at the corner portion of the circumferential groove 20 where the outer end 21b in the tire width direction of the first inclined groove 21 communicates with the second inclined groove 22, the groove width W1OUT is the groove width at the inflection point between the chamfer 20ba and the opening edge of the first inclined groove 21 and at the position passing through the minimum groove width. It is desirable that the groove widths W1IN and W1OUT of the first inclined groove 21 satisfy the relationship of 0.06×1 / 2TDW≦W1IN≦0.12×1 / 2TDW, W1IN≦W1OUT (preferably W1IN<W1OUT) with respect to the developed width TDW. Note that the first inclined groove 21 includes cases where the groove width in the middle of the groove widths W1IN and W1OUT widens or narrows.

[0049] The second inclined groove 22 has a groove width of W2IN at the inner end 22a in the tire width direction and a groove width of W2OUT at the outer end 22b in the tire width direction. In the pneumatic tire 1 of the embodiment, since a chamfer 20aa is provided at the corner portion of the circumferential groove 20 where the inner end 22a in the tire width direction of the second inclined groove 22 communicates with the first inclined groove 21, the groove width W2IN is the groove width at the inflection point between the chamfer 20aa and the opening edge of the second inclined groove 22 and at the position passing through the minimum groove width. In the pneumatic tire 1 of the embodiment, since a chamfer 20ba is provided at the corner portion of the circumferential groove 20 where the outer end 22b in the tire width direction of the second inclined groove 22 communicates with the first inclined groove 21, the groove width W2OUT is the groove width at the inflection point between the chamfer 20ba and the opening edge of the second inclined groove 22 and at the position passing through the minimum groove width. It is desirable that the groove widths W2IN and W2OUT of the second inclined groove 22 satisfy the relationship of W2OUT = W2IN±1 mm. Note that the second inclined groove 22 includes cases where the groove width in the middle of the groove widths W2IN and W2OUT widens or narrows.

[0050] The third inclined groove 23 has a groove width W3IN at the inner end 23a in the tire width direction and a groove width W3OUT at the outer end 23b in the tire width direction. In the pneumatic tire 1 of the embodiment, since a chamfer 23aa is provided at the inner end 23a in the tire width direction of the third inclined groove 23, the groove width W3IN is the groove width at the inflection point between the chamfer 23aa and the opening edge of the third inclined groove 23 and at the position passing through the minimum groove width. In the pneumatic tire 1 of the embodiment, since a chamfer 23ba is provided at the outer end 23b in the tire width direction of the third inclined groove 23, the groove width W3OUT is the groove width at the inflection point between the chamfer 23ba and the opening edge of the third inclined groove 23 and at the position passing through the minimum groove width. It is desirable that the groove width W3IN and W3OUT of the third inclined groove 23 satisfy the relationships of 0.04×1 / 2TDW≦W3IN≦0.30×1 / 2TDW and W3IN≦W3OUT (preferably W3IN < W3OUT) with respect to the developed width TDW. Note that the third inclined groove 23 includes cases where the groove width in the middle of the groove widths W3IN and W3OUT widens or narrows.

[0051] In the pneumatic tire 1 having the above configuration, the first inclined groove 21 and the third inclined groove 23 are characterized in that the groove width gradually increases from the inner side in the tire width direction toward the outer side in the tire width direction.

[0052] According to this pneumatic tire 1, since the groove widths of the first inclined groove 21 and the third inclined groove 23 gradually increase from the inner side in the tire width direction toward the outer side in the tire width direction, drainage from the tire circumferential direction and the tire width direction is possible during straight running and turning, and wet grip performance can be maintained. Further, according to this pneumatic tire 1, by setting the groove width of the shoulder region on the outer side in the tire width direction to be equal to or greater than that of the central region on the inner side in the tire width direction, a decrease in the rigidity of the central region can be prevented, and the wear resistance performance can be improved.

[0053] Here, it is desirable that the pneumatic tire 1 of the embodiment has a design with a directionality in which the rotation direction is defined, as indicated by the arrow R in FIG. 2. The definition of the rotation direction is defined as the rotation direction when the vehicle is moving forward when mounted on the vehicle. Further, the rotation direction is indicated by the pneumatic tire 1 including a rotation direction display portion (not shown) indicating the tire rotation direction. The rotation direction display portion is constituted by, for example, marks or unevenness attached to the side portion 3 of the pneumatic tire 1. The pneumatic tire 1 of the embodiment is defined in the rotation direction that contacts the ground first from the inner ends 21a, 22a, 23a of the respective inclined grooves 21, 22, 23. Since the pneumatic tire 1 of the embodiment has the rotation direction defined in this way, in the first inclined groove 21 and the third inclined groove 23, the ground contact is from a small groove width to a large groove width, so that smooth drainage is possible and wet grip performance can be maintained more effectively.

[0054] As shown in FIG. 2, for the pneumatic tire 1 of the embodiment, the one-sided developed width TDW is divided into four equal parts, and the first divided developed width A1, the second divided developed width A2, the third divided developed width A3, and the fourth divided developed width A4 are defined in order from the tire equatorial plane CL.

[0055] The pneumatic tire 1 having the above configuration is characterized in that the groove area at the first divided developed width A1 is 15% or more and 25% or less of the groove area of the entire one-sided developed width TDW. Further, the pneumatic tire 1 having the above configuration is characterized in that the difference in the groove area at each of the first divided developed width A1, the second divided developed width A2, the third divided developed width A3, and the fourth divided developed width A4 is within 6%.

[0056] According to this pneumatic tire 1, by setting the groove area of the first divided developed width A1 in the central region to 15% or more and 25% or less of the groove area of the entire one-sided developed width TDW, the wear resistance performance can be maintained, and the initial leaning during turning (banking) can be alleviated. Further, according to this pneumatic tire 1, by reducing the difference in the groove area in each region of the first divided developed width A1, the second divided developed width A2, the third divided developed width A3, and the fourth divided developed width A4, the change in rigidity can be reduced, and the vehicle can be smoothly leaned during turning (banking), so that the turning performance can be improved.

[0057] As shown in Fig. 1, the pneumatic tire 1 of the embodiment is characterized in that, with the tread radius in the tire equatorial plane CL being TR and the tread width being TRW, the relationship 0.45 < TR / TRW < 0.65 is satisfied. The tread radius TR is the radius of curvature in the tire width direction on the tread surface 2A. The tread width TRW is the tire width direction dimension of the tread portion 2 in a no-load state where it is mounted on a rim (standard rim) 7 and filled with the standard internal pressure.

[0058] According to this pneumatic tire 1, due to the above relationship between the tread radius TR and the tread width TRW, concentration of the contact pressure in the central region near the tire equatorial plane CL can be prevented, and the wear resistance performance can be improved.

[0059] Incidentally, the pneumatic tire 1 of the embodiment can be applied to the rear tire (rear wheel) of a two-wheeled vehicle, and the pneumatic tire 1' of the reference embodiment described later can be applied to the front tire (front wheel) of a two-wheeled vehicle. And by combining these pneumatic tires 1, 1' as the rear tire and the front tire of a single two-wheeled vehicle, it becomes possible to obtain their respective effects in a single two-wheeled vehicle. Examples of the embodiment

[0060] Fig. 6 is a developed view of the tread portion of a conventional example of a pneumatic tire. Fig. 7 is a chart showing the results of a performance test of the pneumatic tire according to the embodiment. Fig. 8 is a chart showing the results of a performance test of the pneumatic tire according to the embodiment.

[0061] In this example, a performance evaluation test conducted on a conventional pneumatic tire and a pneumatic tire of the example according to the embodiment will be described. The performance evaluation test was a test on wet grip performance, disturbance convergence performance, and wear resistance performance.

[0062] The evaluation test of the wet grip performance was carried out using a test tire of 90 / 90-14 46P (rim 14×1.85) on a test vehicle with a displacement of 108 cm 3It was mounted on the rear tire of a motorcycle and driven on a wet road surface with a water depth of 1 mm, and a sensory evaluation was conducted by a test driver. Then, based on this evaluation result, an index evaluation was performed with the conventional example as the reference (100). In this evaluation, the larger the numerical value, the more preferable it is.

[0063] For the evaluation test of the disturbance convergence performance, a test tire of the above tire size was mounted on the rear tire of the above test vehicle, and it was driven on a dry asphalt-paved road surface, and a sensory evaluation was conducted by a test driver. Then, based on this evaluation result, an index evaluation was performed with the conventional example as the reference (100). In this evaluation, the larger the numerical value, the more preferable it is.

[0064] For the evaluation test of the wear resistance performance, a test tire of the above tire size was mounted on the above test vehicle, and after driving on a dry asphalt-paved road surface, the uneven wear amount associated with the driving distance was measured. Then, based on this measurement result, the driving distance per mm was indexed, and an index evaluation was performed with the conventional example as the reference (100). In this evaluation, the larger the numerical value, the more preferable it is.

[0065] As shown in FIG. 6, the conventional pneumatic tire is a pneumatic tire 101 having a first inclined groove 121 and a third inclined groove 23 that are inclined in the same direction on one side in the tire width direction with respect to the tire equatorial plane CL of the developed width TDW of the tread portion 2. The first inclined groove 121 and the third inclined groove 23 do not straddle the tire equatorial plane CL and straddle the position of 50% (1 / 4 TDW) of the developed width TDW on one side. The third inclined groove 23 is arranged to open at the outermost end 2Aa in the tire width direction.

[0066] As shown in Fig. 2, the pneumatic tire of the embodiment has, on one side in the tire width direction with respect to the tire equatorial plane CL of the developed width TDW of the tread portion 2, a first inclined groove 21, a second inclined groove 22, and a third inclined groove 23 that are inclined with respect to the tire circumferential direction. The first inclined groove 21 and the second inclined groove 22 form a circumferential groove 20 that is alternately communicated in the tire circumferential direction, and the circumferential groove 20 is arranged across the 50% position of the developed width TDW on one side without crossing the tire equatorial plane CL. The third inclined groove 23 is arranged across the 50% position of the developed width TDW on one side outside the circumferential groove 20 in the tire width direction and opens to the outermost end 2Aa in the tire width direction.

[0067] And, as shown in the test results, it can be seen that the pneumatic tire of this embodiment has improved disturbance convergence performance and wear resistance while maintaining wet grip performance compared to the conventional example.

[0068] The disclosure of the embodiment includes the following inventions. [Invention 1] On one side in the tire width direction with respect to the tire equatorial plane of the developed width of the tread portion, it has a first inclined groove, a second inclined groove, and a third inclined groove that are inclined with respect to the tire circumferential direction, the first inclined groove and the second inclined groove form a circumferential groove that is alternately communicated in the tire circumferential direction, and the circumferential groove is arranged across the 50% position of the developed width on one side without crossing the tire equatorial plane, the third inclined groove is arranged across the 50% position of the developed width on one side outside the circumferential groove in the tire width direction and opens to the outermost end in the tire width direction, a tire. [Invention 2] The first inclined groove, the second inclined groove, and the third inclined groove are inclined in the same direction with respect to the tire circumferential direction, taking the angle θ1IN of the inner end in the tire width direction of the first inclined groove with respect to the tire circumferential direction, the angle θ2IN of the inner end in the tire width direction of the second inclined groove with respect to the tire circumferential direction, and the angle θ3IN of the inner end in the tire width direction of the third inclined groove with respect to the tire circumferential direction, satisfying the relationships of θ1IN ≤ θ2IN and θ1IN ≤ θ3IN, Let the angle θ1OUT of the outer end in the tire width direction of the first inclined groove with respect to the tire circumferential direction, the angle θ2OUT of the outer end in the tire width direction of the second inclined groove with respect to the tire circumferential direction, and the angle θ3OUT of the outer end in the tire width direction of the third inclined groove with respect to the tire circumferential direction, satisfy the relationship of θ1IN≦θ1OUT, θ2IN≦θ2OUT, θ3IN≦θ3OUT, The tire according to Invention 1. [Invention 3] The first inclined groove, the second inclined groove, and the third inclined groove are inclined in the same direction with respect to the tire circumferential direction, The angle of the second inclined groove with respect to the tire circumferential direction is different from the angle of the first inclined groove with respect to the tire circumferential direction and the angle of the third inclined groove with respect to the tire circumferential direction, The tire according to Invention 1 or 2. [Invention 4] Provide chamfers on at least one side of the corner portion where the first inclined groove and the second inclined groove communicate, The tire according to any one of Inventions 1 to 3. [Invention 5] When the tire circumferential direction lengths of the second inclined groove and the third inclined groove are projected onto the tire equatorial plane, they do not overlap with each other, The tire according to any one of Inventions 1 to 4. [Invention 6] Let the tire circumferential direction length L1 of the first inclined groove, the tire circumferential direction length L2 of the second inclined groove, the tire circumferential direction length L3 of the third inclined groove, and the developed width TDW, Satisfy the relationship of L2<L3<L1, 0.6×TDW<L1<TDW, L3<0.5×L1, The tire according to any one of Inventions 1 to 5. [Invention 7] The first inclined groove and the third inclined groove have a groove width that increases from the inner side in the tire width direction to the outer side in the tire width direction, The tire according to any one of Inventions 1 to 6. [Invention 8] Divide the unfolded width on one side into four equal parts, and in order from the tire equatorial plane, they are the first divided unfolded width A1, the second divided unfolded width A2, the third divided unfolded width A3, and the fourth divided unfolded width A4. The groove area at the first divided unfolded width A1 is 15% or more and 25% or less of the groove area of the unfolded width on one side, and the difference in the groove area of each of the first divided unfolded width A1, the second divided unfolded width A2, the third divided unfolded width A3, and the fourth divided unfolded width A4 is within 6%. The tire according to any one of Inventions 1 to 7. [Invention 9] Regarding the tread radius TR and the tread width TRW at the tire equatorial plane, Satisfy the relationship of 0.45 < TR / TRW < 0.65. The tire according to any one of Inventions 1 to 8.

[0069] [Reference Embodiment] Hereinafter, the pneumatic tire 1' in the reference embodiment will be described. FIG. 9 is a developed view of the tread portion of the pneumatic tire according to the reference embodiment. FIG. 10 is an enlarged developed view of the tread portion of the pneumatic tire according to the reference embodiment. FIG. 11 is an enlarged developed view of the tread portion of the pneumatic tire according to the reference embodiment. FIG. 12 is an enlarged developed view of the tread portion of the pneumatic tire according to the reference embodiment.

[0070] In the pneumatic tire 1' of the reference embodiment, the same reference numerals as those of the pneumatic tire 1 in Embodiment 1 will be used for the equivalent parts for explanation.

[0071] The pneumatic tire 1' of the reference embodiment is particularly suitable for a tire mounted on the front tire (front wheel) of a two-wheeled vehicle. In this pneumatic tire 1', each groove is formed in the tread surface 2A.

[0072] As shown in FIG. 9, the pneumatic tire 1' has a first inclined groove 21, a second inclined groove 22, and a third inclined groove 23 on the tread surface 2A of the tread portion 2 on both sides in the tire width direction with the tire equatorial plane CL of the developed width TDW of the tread portion 2 as a boundary. Here, the developed width TDW is the dimension obtained by developing the distance between the outermost ends 2Aa on both sides in the tire width direction of the tread surface 2A (tread portion 2). In the pneumatic tire 1' of the embodiment, the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are respectively provided on both sides in the tire width direction with the tire equatorial plane CL as a boundary and are arranged in a targeted manner. Therefore, hereinafter, one side in the tire width direction with the tire equatorial plane CL of the developed width TDW of the tread portion 2 as a boundary will be described.

[0073] The first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are provided inclined with respect to the tire circumferential direction. The first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are provided inclined in the same direction with respect to the tire circumferential direction, and the directions of inclination are the same.

[0074] Both ends 21a, 21b (see FIG. 10) of the first inclined groove 21 terminate within the tread surface 2A of the tread portion 2. Both ends 22a, 22b (see FIG. 10) of the second inclined groove 22 terminate within the tread surface 2A of the tread portion 2. The first inclined groove 21 and the second inclined groove 22 communicate alternately in the tire circumferential direction and constitute a circumferential groove 20 that continuously extends in a zigzag shape in the tire circumferential direction. The circumferential groove 20 is arranged on the inner side in the tire width direction closer to the tire equatorial plane CL on one side in the tire width direction with the tire equatorial plane CL of the developed width TDW of the tread portion 2 as a boundary. The circumferential groove 20 does not straddle the tire equatorial plane CL. "Does not straddle" means that it includes contacting the tire equatorial plane CL, which is a reference line extending in the tire circumferential direction, but the groove does not cross the tire equatorial plane CL. Further, the circumferential groove 20 is arranged so as to straddle a reference line C, which is at the position of 50% (1 / 4 TDW) of the developed width TDW on one side, in the tire width direction. "Straddle" means crossing a reference line C extending in the tire circumferential direction. It should be noted that the groove depth of the first inclined groove 21 is preferably in the range of 3 mm or more and 8 mm or less. The groove depth of the second inclined groove 22 is preferably in the range of 1 mm or more and 8 mm or less.

[0075] The third inclined groove 23 is arranged independently without communicating with the circumferential groove 20. The third inclined groove 23 is arranged on the outer side in the tire width direction away from the tire equatorial plane CL than the circumferential groove 20. The third inclined groove 23 is arranged between the first inclined groove 21 and the second inclined groove 22 forming the circumferential groove 20 in the tire circumferential direction. The outer end of the third inclined groove 23 in the tire width direction opens to the outermost end 2Aa in the tire width direction of the tread surface 2A, and the inner end in the tire width direction terminates within the tread surface 2A of the tread portion 2. Further, the third inclined groove 23 does not straddle the reference line C which is at the position of 50% (1 / 4 TDW) of the unfolded width TDW on one side. "Does not straddle" means that it includes contacting the reference line C extending in the tire circumferential direction, but the groove does not cross the reference line C. Note that the groove depth of the third inclined groove 23 is desirably in the range of 2 mm or more and 8 mm or less.

[0076] As described above, in this pneumatic tire 1', the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are respectively provided on both sides in the tire width direction with the tire equatorial plane CL as the boundary, and are symmetrically arranged. Specifically, in one side in the tire width direction with the tire equatorial plane CL as the boundary, one first inclined groove 21, one second inclined groove 22, and one third inclined groove 23 are arranged at one pitch P in the tire circumferential direction. That is, in one side in the tire width direction with the tire equatorial plane CL as the boundary, a part of the circumferential groove 20 formed by one first inclined groove 21 and one second inclined groove 22, and one third inclined groove 23 arranged between these first inclined groove 21 and second inclined groove 22 in the tire circumferential direction are arranged at one pitch P in the tire circumferential direction. And on both sides in the tire width direction with the tire equatorial plane CL as the boundary, one pitch P formed by one first inclined groove 21, one second inclined groove 22, and one third inclined groove 23 is arranged with a shift in the tire circumferential direction in the range of 30% or more and 80% or less between one side and the other side when one pitch P is taken as 100%.

[0077] The pneumatic tire 1' with the above configuration has, on one side in the tire width direction with the tire equatorial plane CL of the tread width TDW as a boundary, a first inclined groove 21, a second inclined groove 22, and a third inclined groove 23 that are inclined with respect to the tire circumferential direction. The first inclined groove 21 and the second inclined groove 22 constitute a circumferential groove 20 that is alternately communicated in the tire circumferential direction. The circumferential groove 20 is arranged across the 50% position of the one-side tread width TDW without straddling the tire equatorial plane CL, and the third inclined groove 23 is arranged to open at the outermost end 2Aa in the tire width direction without straddling the 50% position of the one-side tread width TDW outside the circumferential groove 20 in the tire width direction.

[0078] According to this pneumatic tire 1', since the circumferential groove 20 composed of the first inclined groove 21 and the second inclined groove 22 straddles the 50% position of the one-side tread width TDW and the third inclined groove 23 is formed without straddling the 50% position of the one-side tread width TDW, the rigidity during straight running can be maintained, and while maintaining the turning performance at the initial stage during turning (banking in the case of a two-wheeled vehicle), the wear resistance performance of the central region of the tread width TDW can be improved.

[0079] As shown in FIG. 9, the pneumatic tire 1' of the embodiment has a center circumferential groove 24.

[0080] The center circumferential groove 24 is formed linearly along the tire circumferential direction. The center circumferential groove 24 is arranged on the tire equatorial plane CL so as to pass through the tire equatorial plane CL. Note that the groove depth of the center circumferential groove 24 is preferably in the range of 3 mm or more and 9 mm or less.

[0081] The pneumatic tire 1' with the above configuration is characterized by having a center circumferential groove 24 passing through the tire equatorial plane CL.

[0082] According to this pneumatic tire 1', by arranging the center circumferential groove 24 on the tire equatorial plane CL, the handling stability performance during straight running can be improved, the rigidity near the tire equatorial plane CL can be softened, and it is easier to start banking during turning, thereby maintaining the turning performance.

[0083] Further, in the pneumatic tire 1' having the above-described configuration, as shown in FIG. 10, the center circumferential groove 24 is characterized in that its groove width Wcc satisfies the relationship of Wcc ≦ 0.1 × 1 / 2 TDW with respect to the unfolded width TDW on one side.

[0084] According to this pneumatic tire 1', by setting the groove width Wcc of the center circumferential groove 24 to 0.1 × 1 / 2 TDW or less, the groove width Wcc of the center circumferential groove 24 in the unfolded width TDW on one side is defined, and the handling stability performance can be improved while maintaining the turning performance and wear resistance performance.

[0085] As shown in FIG. 10, in the pneumatic tire 1' of the embodiment, the angles of the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 that are inclined in the same direction with respect to the tire circumferential direction are defined.

[0086] For the first inclined groove 21, let the angle of the inner end 21a in the tire width direction with respect to the tire circumferential direction be θ1IN, and the angle of the outer end 21b in the tire width direction with respect to the tire circumferential direction be θ1OUT. Each of the angles θ1IN and θ1OUT of the first inclined groove 21 is an angle on the side of 90° or less with respect to the tire circumferential direction at the position where the center line 22c passing through the center of the groove width of the second inclined groove 22 along the extending direction of the second inclined groove 22 intersects the center line 21c passing through the center of the groove width of the first inclined groove 21 along the extending direction of the first inclined groove 21. The first inclined groove 21 may be formed as a straight line, but in the embodiment, it is formed to be curved. When the first inclined groove 21 is a straight line, the angles θ1IN and θ1OUT of the first inclined groove 21 are the angles formed by the center line 21c and the tire circumferential direction at the above intersection because the center line 21c is a straight line. On the other hand, when the first inclined groove 21 is curved, the angles θ1IN and θ1OUT of the first inclined groove 21 are the angles formed by the tangent line of the center line 21c and the tire circumferential direction at the above intersection because the center line 21c is curved. In the pneumatic tire 1' of the embodiment, it is desirable that the angle θ1IN of the inner end 21a of the first inclined groove 21 is in the range of 4° or more and 13° or less. Also, in the pneumatic tire 1' of the embodiment, it is desirable that the angle θ1OUT of the outer end 21b of the first inclined groove 21 is equal to or greater than the angle θ1IN and is greater than the angle θ1IN.

[0087] For the second inclined groove 22, the angle of the inner end 22a in the tire width direction with respect to the tire circumferential direction is defined as θ2IN, and the angle of the outer end 22b in the tire width direction with respect to the tire circumferential direction is defined as θ2OUT. Each of the angles θ2IN and θ2OUT of the second inclined groove 22 is an angle on the side of 90° or less with respect to the tire circumferential direction at the position where the center line 21c of the first inclined groove 21 intersects the center line 22c passing through the center of the groove width of the second inclined groove 22 along the extending direction of the second inclined groove 22. The second inclined groove 22 may be formed in a curved shape, but in the embodiment, it is formed in a straight line. When the second inclined groove 22 is straight, the angles θ2IN and θ2OUT of the second inclined groove 22 are the angles formed by the center line 22c and the tire circumferential direction at the above intersection because the center line 22c is straight. On the other hand, when the second inclined groove 22 is curved, the angles θ2IN and θ2OUT of the second inclined groove 22 are the angles formed by the tangent line of the center line 22c and the tire circumferential direction at the above intersection because the center line 22c is curved. In the pneumatic tire 1' of the embodiment, the angle θ2IN of the inner end 22a of the second inclined groove 22 is equal to or greater than the angle θ1IN of the inner end 21a of the first inclined groove 21, and is desirably 45° or more and 90° or less. Also, in the pneumatic tire 1' of the embodiment, the angle θ2OUT of the outer end 22b of the second inclined groove 22 is equal to or greater than the angle θ2IN, and is desirably the angle θ2IN + 15°.

[0088] The third inclined groove 23 has an angle θ3IN of the inner end 23a in the tire width direction with respect to the tire circumferential direction, and an angle θ3OUT of the outer end 23b in the tire width direction with respect to the tire circumferential direction. Each angle θ3IN of the third inclined groove 23 is an angle on the side of 90° or less with respect to the tire circumferential direction at the end position of the third inclined groove 23 on the center line 23c passing through the center of the groove width of the third inclined groove 23 along the extending direction of the third inclined groove 23. The angle θ3OUT of the third inclined groove 23 is an angle on the side of 90° or less with respect to the tire circumferential direction at the position where the outer end 23b of the third inclined groove 23 opens on the center line 23c of the third inclined groove 23. When a chamfer 23ba is provided at the opening edge of the outer end 23b of the third inclined groove 23, it is the angle on the side of 90° or less with respect to the tire circumferential direction at the inflection point between this chamfer 23ba and the opening edge and at the position passing through the minimum groove width. The third inclined groove 23 may be formed in a straight line, but in the embodiment, it is formed to be curved. When the third inclined groove 23 is a straight line, the angle θ3IN and the angle θ3OUT of the third inclined groove 23 are the angles formed by the center line 23c and the tire circumferential direction because the center line 23c is a straight line. On the other hand, when the third inclined groove 23 is curved, the angle θ3IN and the angle θ3OUT of the third inclined groove 23 are the angles formed by the tangent line of the center line 23c and the tire circumferential direction because the center line 23c is curved. In the pneumatic tire 1' of the embodiment, it is desirable that the angle θ3IN of the inner end 23a of the third inclined groove 23 is in the range of 35° or more and 45° or less. Also, in the pneumatic tire 1' of the embodiment, the angle θ3OUT of the outer end 23b of the third inclined groove 23 is preferably equal to or greater than the angle θ3IN and greater than the angle θ3IN.

[0089] In the pneumatic tire 1' having the above configuration, the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are inclined in the same direction with respect to the tire circumferential direction, and the angles with respect to the tire circumferential direction satisfy the relationships of θ1IN≦θ2IN, θ1IN≦θ3IN, and also satisfy the relationships of θ1IN≦θ1OUT, θ2IN≦θ2OUT, θ3IN≦θ3OUT.

[0090] According to this pneumatic tire 1', by means of the inclined first inclined groove 21, second inclined groove 22, and third inclined groove 23, inclined grooves with a relatively low angle with respect to the tire circumferential direction are arranged within the ground contact surface during straight running, thereby improving the handling stability performance. Further, according to this pneumatic tire 1', by means of the inclined first inclined groove 21, second inclined groove 22, and third inclined groove 23, during banked turning, by setting a relatively high angle with respect to the tire circumferential direction, while maintaining the lateral rigidity and the turning performance, the wear resistance can be improved.

[0091] Moreover, in the pneumatic tire 1' having the above configuration, the angle θ2IN (θ2OUT) of the second inclined groove 22 with respect to the tire circumferential direction is different from the angle θ1IN (θ1OUT) of the first inclined groove 21 with respect to the tire circumferential direction and the angle θ3IN (θ3OUT) of the third inclined groove 23 with respect to the tire circumferential direction.

[0092] According to this pneumatic tire 1', by means of the inclined first inclined groove 21, second inclined groove 22, and third inclined groove 23, drainage is performed in the tire width direction during straight running, thereby maintaining the wet grip performance. Further, according to this pneumatic tire 1', due to the above relationship of the angles of the second inclined groove 22 with the first inclined groove 21 and the third inclined groove 23, the rigidity balance between the tire circumferential direction and the tire width direction can be adjusted, and the disturbance convergence performance can be improved.

[0093] As shown in FIG. 10, in the pneumatic tire 1' of the embodiment, chamfers are provided at the corner portion of the circumferential groove 20 where the first inclined groove 21 and the second inclined groove 22 communicate, and at the end portion of the third inclined groove 23, respectively.

[0094] The corner portion of the circumferential groove 20 where the first inclined groove 21 and the second inclined groove 22 communicate can be formed with an acute angle as it is, but chamfers 20aa and 20ba are provided so as to cut the corner portion. The chamfer 20aa is provided on both sides of the inner corner and the outer corner of the corner portion of the circumferential groove 20 where the inner end 21a of the first inclined groove 21 and the inner end 22a of the second inclined groove 22 communicate. The chamfer 20aa may be provided on at least one side of the inner corner and the outer corner of the corner portion. The chamfer 20ba is provided on both sides of the inner corner and the outer corner of the corner portion of the circumferential groove 20 where the outer end 21b of the first inclined groove 21 and the outer end 22b of the second inclined groove 22 communicate. The chamfer 20ba may be provided on at least one side of the inner corner and the outer corner of the corner portion. The chamfers 20aa and 20ba are preferably formed as arc surfaces in the embodiment, but may be formed as flat surfaces.

[0095] The inner end 23a and the outer end 23b of the third inclined groove 23 can be formed with an acute angle as it is, but chamfers 23aa and 23ba are provided so as to cut the portion. The chamfer 23aa is provided at the inner end 23a of the third inclined groove 23. The chamfer 23ba is provided at the outer end 23b of the third inclined groove 23 and on both opening edges that open to the outermost end 2Aa in the tire width direction of the tread surface 2A. The chamfers 23aa and 23ba are preferably formed as arc surfaces in the embodiment, but may be formed as flat surfaces.

[0096] The pneumatic tire 1' having the above configuration is characterized in that chamfers 20aa and 20ba are provided on at least one side of the corner portion where the first inclined groove 21 and the second inclined groove 22 communicate.

[0097] According to this pneumatic tire 1', the chamfers 20aa and 20ba of the corner portion where the first inclined groove 21 and the second inclined groove 22 communicate can make the groove width of the corner portion constant, suppress the occurrence of local land portion changes, suppress the occurrence of uneven wear, and improve the wear resistance performance.

[0098] As shown in FIG. 11, the pneumatic tire 1' of the embodiment defines the relationship of the tire circumferential lengths L1, L2, and L3 of the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23.

[0099] In the pneumatic tire 1', in the first inclined groove 21, the circumferential length of the tire between the inner end 21a and the outer end 21b is defined as L1. In the pneumatic tire 1', in the second inclined groove 22, the circumferential length of the tire between the inner end 22a and the outer end 22b is defined as L2. In the pneumatic tire 1', in the third inclined groove 23, the circumferential length of the tire between the inner end 23a and the outer end 23b is defined as L3.

[0100] In the pneumatic tire 1' having the above configuration, when the circumferential length L2 of the second inclined groove 22 and the circumferential length L3 of the third inclined groove 23 are projected onto the tire equatorial plane CL, they do not overlap with each other.

[0101] According to this pneumatic tire 1', by setting the projections of the second inclined groove 22 and the third inclined groove 23 onto the tire equatorial plane CL not to overlap in the circumferential direction of the tire, a local reduction in the land portion can be prevented, the occurrence of uneven wear can be suppressed, and the wear resistance performance can be improved.

[0102] Further, in the pneumatic tire 1' having the above configuration, the circumferential length L1 of the first inclined groove 21, the circumferential length L2 of the second inclined groove 22, the circumferential length L3 of the third inclined groove 23, and the tread width TDW satisfy the relationships of L2 < L3 < L1, 0.6×TDW < L1 < TDW, and L3 < 0.3×L1.

[0103] According to this pneumatic tire 1', since one or more pitches of the first inclined groove 21 having a relatively low angle with respect to the circumferential direction of the tire enter the contact area during grounding together with the center circumferential groove 24, the handling stability performance during straight running can be improved. Also, according to this pneumatic tire 1', by making the circumferential length L3 of the third inclined groove 23 shorter than the circumferential length L1 of the first inclined groove 21, the contact area of the land portion during turning (banking) can be maintained, and the handling stability performance can be improved.

[0104] As shown in FIG. 12, in the pneumatic tire 1' of the embodiment, the groove widths of the first inclined groove 21, the second inclined groove 22, and the third inclined groove 23 are defined.

[0105] For the first inclined groove 21, the groove width at the inner end 21a in the tire width direction is denoted as W1IN, and the groove width at the outer end 21b in the tire width direction is denoted as W1OUT. In the pneumatic tire 1' of the embodiment, since a chamfer 20aa is provided at the corner portion of the circumferential groove 20 where the inner end 21a in the tire width direction of the first inclined groove 21 communicates with the second inclined groove 22, the groove width W1IN is the groove width at the inflection point between the chamfer 20aa and the opening edge of the first inclined groove 21 and at the position passing through the minimum groove width. In the pneumatic tire 1' of the embodiment, since a chamfer 20ba is provided at the corner portion of the circumferential groove 20 where the outer end 21b in the tire width direction of the first inclined groove 21 communicates with the second inclined groove 22, the groove width W1OUT is the groove width at the inflection point between the chamfer 20ba and the opening edge of the first inclined groove 21 and at the position passing through the minimum groove width. It is desirable that the groove widths W1IN and W1OUT of the first inclined groove 21 satisfy the relationship of 0.05×1 / 2TDW≦W1IN≦0.10×1 / 2TDW, W1IN≦W1OUT (preferably W1IN<W1OUT) with respect to the developed width TDW. Note that the first inclined groove 21 includes cases where the groove width in the middle of W1IN and W1OUT widens or narrows.

[0106] For the second inclined groove 22, the groove width at the inner end 22a in the tire width direction is denoted as W2IN, and the groove width at the outer end 22b in the tire width direction is denoted as W2OUT. In the pneumatic tire 1' of the embodiment, since a chamfer 20aa is provided at the corner portion of the circumferential groove 20 where the inner end 22a in the tire width direction of the second inclined groove 22 communicates with the first inclined groove 21, the groove width W2IN is the groove width at the inflection point between the chamfer 20aa and the opening edge of the second inclined groove 22 and at the position passing through the minimum groove width. In the pneumatic tire 1' of the embodiment, since a chamfer 20ba is provided at the corner portion of the circumferential groove 20 where the outer end 22b in the tire width direction of the second inclined groove 22 communicates with the first inclined groove 21, the groove width W2OUT is the groove width at the inflection point between the chamfer 20ba and the opening edge of the second inclined groove 22 and at the position passing through the minimum groove width. It is desirable that the groove widths W2IN and W2OUT of the second inclined groove 22 satisfy the relationship of W2OUT = W2IN±1mm. Note that the second inclined groove 22 includes cases where the groove width in the middle of W2IN and W2OUT widens or narrows.

[0107] The third inclined groove 23 has a groove width of W3IN at the inner end 23a in the tire width direction and a groove width of W3OUT at the outer end 23b in the tire width direction. In the pneumatic tire 1' of the embodiment, since a chamfer 23aa is provided at the inner end 23a in the tire width direction of the third inclined groove 23, the groove width W3IN is the groove width at the inflection point between the chamfer 23aa and the opening edge of the third inclined groove 23 and at the position passing through the minimum groove width. In the pneumatic tire 1' of the embodiment, since a chamfer 23ba is provided at the outer end 23b in the tire width direction of the third inclined groove 23, the groove width W3OUT is the groove width at the inflection point between the chamfer 23ba and the opening edge of the third inclined groove 23 and at the position passing through the minimum groove width. It is desirable that the groove width W3IN and W3OUT of the third inclined groove 23 satisfy the relationship of 0.03×1 / 2TDW≦W3IN≦0.30×1 / 2TDW and W3IN≦W3OUT (preferably W3IN<W3OUT) with respect to the developed width TDW. Note that the third inclined groove 23 includes cases where the groove width in the middle of the groove widths W3IN and W3OUT widens or narrows.

[0108] In the pneumatic tire 1' having the above configuration, the first inclined groove 21 and the third inclined groove 23 are characterized in that the groove width gradually increases from the inner side in the tire width direction toward the outer side in the tire width direction.

[0109] According to this pneumatic tire 1', since the groove widths of the first inclined groove 21 and the third inclined groove 23 gradually increase from the inner side in the tire width direction toward the outer side in the tire width direction, by setting the groove width of the shoulder region on the outer side in the tire width direction to be equal to or greater than that of the central region on the inner side in the tire width direction, it is possible to prevent a decrease in the rigidity of the central region, and improve the handling stability performance while maintaining the turning performance and the wear resistance performance.

[0110] Here, it is desirable that the pneumatic tire 1' of the embodiment has a design with a defined directionality in the rotational direction, as indicated by the arrow R in FIG. 9. The definition of the rotational direction is defined as the rotational direction when the vehicle is moving forward during vehicle mounting. Further, the rotational direction is indicated by the pneumatic tire 1' being provided with a rotational direction display portion (not shown) indicating the tire rotational direction. The rotational direction display portion is constituted by, for example, marks or unevenness attached to the side portion 3 of the pneumatic tire 1'. The pneumatic tire 1' of the embodiment is defined in the rotational direction that contacts the ground first from the inner ends 21a, 22a, 23a of the respective inclined grooves 21, 22, 23. By defining the rotational direction in this way, in the first inclined groove 21 and the third inclined groove 23 of the pneumatic tire 1' of the embodiment, since the groove width contacts the ground from a small groove width to a large groove width, it is possible to prevent a decrease in rigidity in the central region, and while maintaining the turning performance and wear resistance performance, a remarkable effect of improving the handling stability performance can be obtained.

[0111] As shown in FIG. 9, for the pneumatic tire 1' of the embodiment, the one-sided developed width TDW is divided into four equal parts, and the first divided developed width A1, the second divided developed width A2, the third divided developed width A3, and the fourth divided developed width A4 are defined in order from the tire equatorial plane CL.

[0112] In the pneumatic tire 1' having the above configuration, the groove area at the first divided developed width A1 is characterized by being 15% or more and 25% or less of the groove area of the entire one-sided developed width TDW. Further, in the pneumatic tire 1' having the above configuration, the difference in the groove area at each of the first divided developed width A1, the second divided developed width A2, the third divided developed width A3, and the fourth divided developed width A4 is within 6%. Further, in the pneumatic tire 1' having the above configuration, the groove area of the fourth divided developed width A4 is the smallest and is characterized by being 10% or more of the groove area of the one-sided developed width TDW.

[0113] According to this pneumatic tire 1', by setting the groove area of the first divided expansion width A1 in the central region to be 15% or more and 25% or less of the groove area of the entire expansion width TDW on one side, the wear resistance performance can be maintained, and the initial tilting during turning (banking) can be alleviated. Further, according to this pneumatic tire 1', by reducing the difference in groove area in each region of the first divided expansion width A1, the second divided expansion width A2, the third divided expansion width A3, and the fourth divided expansion width A4, the change in rigidity can be reduced, and the vehicle can be smoothly tilted during turning (banking), so the turning performance can be improved. Further, according to this pneumatic tire 1', if the groove area of the fourth divided expansion width A4 in the shoulder region is reduced, it is possible to suppress the vehicle body from tilting too much.

[0114] As shown in FIG. 1, the pneumatic tire 1' of the embodiment is characterized in that, with the tread radius at the tire equatorial plane CL being TR and the tread width being TRW, the relationship of 0.45 < TR / TRW < 0.65 is satisfied. The tread radius TR is the radius of curvature in the tire width direction on the tread surface 2A. The tread width TRW is the tire width direction dimension of the tread portion 2 in a non-loaded state where the rim (normal rim) 7 is mounted and filled with the normal internal pressure.

[0115] According to this pneumatic tire 1', due to the above relationship between the tread radius TR and the tread width TRW, the concentration of the contact pressure in the central region near the tire equatorial plane CL can be prevented, and the wear resistance performance can be improved.

[0116] By the way, the pneumatic tire 1' of the reference embodiment can be applied to the front tire (front wheel) of a two-wheeled vehicle, and the pneumatic tire 1 of the above-described embodiment can be applied to the rear tire (rear wheel) of a two-wheeled vehicle. And by combining these pneumatic tires 1, 1' as the rear tire and the front tire of a single two-wheeled vehicle, it becomes possible to obtain their respective effects in a single two-wheeled vehicle. Examples of the reference embodiment

[0117] FIG. 13 is a chart showing the results of the performance test of the pneumatic tire according to the reference embodiment. FIG. 14 is a chart showing the results of the performance test of the pneumatic tire according to the reference embodiment.

[0118] In this embodiment, a performance evaluation test conducted on the pneumatic tire of the conventional example and the pneumatic tire of the embodiment according to the reference form will be described. The performance evaluation test included tests on cornering performance, handling stability performance, and wear resistance performance.

[0119] For the evaluation tests of cornering performance and handling stability performance, a test tire of 80 / 90-14 40P (rim 14×1.85) was mounted on the front tire of a motorcycle with a displacement of 108 cm 3 as the test vehicle, and the test driver's sensory evaluation was carried out by driving on a dry asphalt-paved road surface. Then, based on this evaluation result, an index evaluation was performed with the conventional example as the reference (100). For this evaluation, the larger the numerical value, the more preferable.

[0120] For the evaluation test of wear resistance performance, a test tire of the above tire size was mounted on the above test vehicle, and the uneven wear amount associated with the driving distance was measured after driving on a dry asphalt-paved road surface. Then, based on this measurement result, the driving distance per mm was indexed, and an index evaluation was performed with the conventional example as the reference (100). For this evaluation, the larger the numerical value, the more preferable.

[0121] As shown in FIG. 6, the pneumatic tire of the conventional example is a pneumatic tire 1'01 having a first inclined groove 121 and a third inclined groove 23 that are inclined in the same direction on one side in the tire width direction with respect to the tire equatorial plane CL of the developed width TDW of the tread portion 2. The first inclined groove 121 and the third inclined groove 23 do not straddle the tire equatorial plane CL and straddle the position of 50% (1 / 4 TDW) of the developed width TDW on one side. The third inclined groove 23 is arranged to open at the outermost end 2Aa in the tire width direction.

[0122] As shown in Fig. 9, the pneumatic tire of the embodiment has, on one side in the tire width direction with respect to the tire equatorial plane CL of the developed width TDW of the tread portion 2, a first inclined groove 21, a second inclined groove 22, and a third inclined groove 23 that are inclined with respect to the tire circumferential direction. The first inclined groove 21 and the second inclined groove 22 constitute a circumferential groove 20 that is alternately communicated in the tire circumferential direction. The circumferential groove 20 is arranged across the 50% position of the developed width TDW on one side without straddling the tire equatorial plane CL. The third inclined groove 23 is arranged to open at the outermost end 2Aa in the tire width direction across the 50% position of the developed width TDW on one side outside the circumferential groove 20 in the tire width direction without straddling it.

[0123] And, as shown in the test results, it can be seen that the pneumatic tire of this embodiment maintains the turning performance with respect to the conventional example, and the handling stability performance and the wear resistance performance are improved.

[0124] The disclosure of the reference form includes the following inventions. [Invention 1] On one side in the tire width direction with respect to the tire equatorial plane of the developed width of the tread portion, having a first inclined groove, a second inclined groove, and a third inclined groove that are inclined with respect to the tire circumferential direction, the first inclined groove and the second inclined groove constitute a circumferential groove that is alternately communicated in the tire circumferential direction, and the circumferential groove is arranged across the 50% position of the developed width on one side without straddling the tire equatorial plane, the third inclined groove is arranged to open at the outermost end in the tire width direction across the 50% position of the developed width on one side outside the circumferential groove in the tire width direction without straddling it, a tire. [Invention 2] having a center circumferential groove passing through the tire equatorial plane, the tire according to Invention 1. [Invention 3] Regarding the groove width Wcc of the center circumferential groove and the developed width as TDW, satisfying the relationship of Wcc ≦ 0.1 × 1 / 2TDW, the tire according to Invention 2. [Invention 4] The first inclined groove, the second inclined groove, and the third inclined groove are inclined in the same direction with respect to the tire circumferential direction, Let the angle θ1IN of the inner end in the tire width direction of the first inclined groove with respect to the tire circumferential direction, the angle θ2IN of the inner end in the tire width direction of the second inclined groove with respect to the tire circumferential direction, and the angle θ3IN of the inner end in the tire width direction of the third inclined groove with respect to the tire circumferential direction, Satisfy the relationship of θ1IN ≤ θ2IN, θ1IN ≤ θ3IN, Let the angle θ1OUT of the outer end in the tire width direction of the first inclined groove with respect to the tire circumferential direction, the angle θ2OUT of the outer end in the tire width direction of the second inclined groove with respect to the tire circumferential direction, and the angle θ3OUT of the outer end in the tire width direction of the third inclined groove with respect to the tire circumferential direction, Satisfy the relationship of θ1IN ≤ θ1OUT, θ2IN ≤ θ2OUT, θ3IN ≤ θ3OUT, The tire according to any one of Inventions 1 to 3. [Invention 5] The first inclined groove, the second inclined groove, and the third inclined groove are inclined in the same direction with respect to the tire circumferential direction, The angle of the second inclined groove with respect to the tire circumferential direction is different from the angle of the first inclined groove with respect to the tire circumferential direction and the angle of the third inclined groove with respect to the tire circumferential direction, The tire according to any one of Inventions 1 to 4. [Invention 6] Provide chamfers on at least one side of the corner portion where the first inclined groove and the second inclined groove communicate, The tire according to any one of Inventions 1 to 5. [Invention 7] When the tire circumferential lengths of the second inclined groove and the third inclined groove are projected onto the tire equatorial plane, they do not overlap with each other, The tire according to any one of Inventions 1 to 6. [Invention 8] Let the tire circumferential length L1 of the first inclined groove, the tire circumferential length L2 of the second inclined groove, the tire circumferential length L3 of the third inclined groove, and the developed width TDW, Satisfy the relationship of L2 < L3 < L1, 0.6 × TDW < L1 < TDW, L3 < 0.5 × L1, The tire according to any one of Inventions 1 to 7. [Invention 9] The first inclined groove and the third inclined groove have a groove width that increases from the inner side in the tire width direction toward the outer side in the tire width direction. The tire according to any one of Inventions 1 to 8. [Invention 10] Divide the unfolding width on one side into four equal parts, and in order from the tire equatorial plane, they are the first divided unfolding width A1, the second divided unfolding width A2, the third divided unfolding width A3, and the fourth divided unfolding width A4. The groove area at the first divided unfolding width A1 is 15% or more and 25% or less of the groove area of the unfolding width on one side, the difference in the groove area at the first divided unfolding width A1, the second divided unfolding width A2, the third divided unfolding width A3, and the fourth divided unfolding width A4 is within 6%, and the groove area of the fourth divided unfolding width A4 is the smallest and is 10% or more of the groove area of the unfolding width on one side. The tire according to any one of Inventions 1 to 9. [Invention 11] Regarding the tread radius TR and the tread width TRW at the tire equatorial plane. Satisfy the relationship of 0.45 < TR / TRW < 0.65. The tire according to any one of Inventions 1 to 10.

[0125] Also, in the above-described embodiments and reference embodiments, the pneumatic tire 1, 1' has been described as an example of a tire. This pneumatic tire 1, 1' can be filled with air, an inert gas such as nitrogen, and other gases. However, the configuration of the tread pattern of the pneumatic tire 1, 1' described in the embodiments and reference embodiments can be arbitrarily applied to other tires within the scope obvious to those skilled in the art. Examples of other tires include, for example, airless tires, solid tires, and the like.

Explanation of Reference Numerals

[0126] 1 Pneumatic tire (tire) 2 Tread portion 2Aa Outermost end in the tire width direction 20 Circumferential groove Chamfers on the 20aa and 20ba surfaces 21 First inclined groove 21a Inner end in the tire width direction 21b Outer end in the tire width direction 22 Second inclined groove 22a Inner end in the tire width direction 22b Outer end in the tire width direction 23 Third inclined groove 23a Inner end in the tire width direction 23b Outer end in the tire width direction A1 First divided expansion width A2 Second divided expansion width A3 Third divided expansion width A4 Fourth divided expansion width

Claims

1. On one side in the tire width direction with the tire equatorial plane as a boundary of the developed width of the tread portion, It has a first inclined groove, a second inclined groove, and a third inclined groove that are inclined with respect to the tire circumferential direction, The first inclined groove and the second inclined groove constitute a circumferential groove that is alternately communicated in the tire circumferential direction, and the circumferential groove is arranged across the 50% position of the developed width on one side without straddling the tire equatorial plane, The third inclined groove is arranged across the 50% position of the developed width on one side outside the circumferential groove in the tire width direction and opens at the outermost end in the tire width direction, Tire.

2. The first inclined groove, the second inclined groove, and the third inclined groove are inclined in the same direction with respect to the tire circumferential direction, Let the angle θ1IN of the inner end in the tire width direction of the first inclined groove with respect to the tire circumferential direction, the angle θ2IN of the inner end in the tire width direction of the second inclined groove with respect to the tire circumferential direction, and the angle θ3IN of the inner end in the tire width direction of the third inclined groove with respect to the tire circumferential direction, Satisfy the relationship of θ1IN ≤ θ2IN, θ1IN ≤ θ3IN, Let the angle θ1OUT of the outer end in the tire width direction of the first inclined groove with respect to the tire circumferential direction, the angle θ2OUT of the outer end in the tire width direction of the second inclined groove with respect to the tire circumferential direction, and the angle θ3OUT of the outer end in the tire width direction of the third inclined groove with respect to the tire circumferential direction, Satisfy the relationship of θ1IN ≤ θ1OUT, θ2IN ≤ θ2OUT, θ3IN ≤ θ3OUT, The tire according to claim 1.

3. The first inclined groove, the second inclined groove, and the third inclined groove are inclined in the same direction with respect to the tire circumferential direction, The angle of the second inclined groove with respect to the tire circumferential direction is different from the angle of the first inclined groove with respect to the tire circumferential direction and the angle of the third inclined groove with respect to the tire circumferential direction, The tire according to claim 1.

4. Chamfers are provided on at least one side of the corner portion where the first inclined groove and the second inclined groove communicate. The tire according to claim 1.

5. When the tire circumferential direction lengths of the second inclined groove and the third inclined groove are projected onto the tire equatorial plane, they do not overlap with each other. The tire according to claim 1.

6. Let the tire circumferential direction length L1 of the first inclined groove, the tire circumferential direction length L2 of the second inclined groove, the tire circumferential direction length L3 of the third inclined groove, and the developed width TDW. Satisfy the relationships of L2 < L3 < L1, 0.6 × TDW < L1 < TDW, and L3 < 0.5 × L1. The tire according to claim 1.

7. The first inclined groove and the third inclined groove have a groove width that increases from the inner side in the tire width direction to the outer side in the tire width direction. The tire according to claim 1.

8. Divide the developed width on one side into four equal parts, and in order from the tire equatorial plane, they are the first divided developed width A1, the second divided developed width A2, the third divided developed width A3, and the fourth divided developed width A4. The groove area at the first divided developed width A1 is 15% or more and 25% or less of the groove area of the developed width on one side, and the difference in the groove areas at the first divided developed width A1, the second divided developed width A2, the third divided developed width A3, and the fourth divided developed width A4 is within 6%. The tire according to claim 1.

9. Let the tread radius TR and the tread width TRW on the tire equatorial plane. Satisfy the relationship of 0.45 < TR / TRW < 0.

65. The tire according to claim 1.

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