JP2015134581A - pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire improved in wet braking performance.SOLUTION: In the pneumatic tire, first land portions 16 at respective outermost sides in a tire width direction and second land portions 18 provided inside in the tire width direction of the first land portions 16 are sectionally formed by a plurality of circumferential main grooves 14. In the second land portions 18 are arranged wave-like grooves 20 that have predetermined amplitude in the tire width direction and are extended in a tire circumference direction, and in the second land portions 18 are arranged a plurality of chamfered sipes 22, where the chamfered sipes 22 are extended from the circumferential main grooves 14 and terminated inside the second land portions 18. The chamfered sipes 22 in each second land portion 18 are alternately extended from adjacent circumferential main grooves 14 and 14 in the tire circumference direction.

Description

  The present invention relates to a pneumatic tire with improved braking performance on a wet road surface (hereinafter referred to as “wet braking performance”).

  Conventionally, as a means for improving wet braking performance, a method of arranging at least one of a sipe and a lug groove so as to cross a rib-like land portion is known (see, for example, Patent Document 1).

JP 2013-49407 A

  However, as disclosed in Patent Document 1, when the sipe is communicated with the circumferential groove, it is unclear whether the rigidity of the rib-like land portion can be sufficiently secured, and there is room for improvement in wet braking performance. It is thought that there is.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a pneumatic tire with improved wet braking performance.

  The pneumatic tire according to the present invention includes a plurality of circumferential main grooves, and the circumferential main grooves allow the outermost first land portion on each side in the tire width direction and the tire width direction to be greater than the first land portion. A pneumatic tire in which an inner second land portion is partitioned. A wavy groove extending in the tire circumferential direction with a predetermined amplitude in the tire width direction is disposed in the second land portion. A plurality of chamfered sipes are disposed in the second land portion. The chamfer sipe extends from the circumferential main groove and terminates inside the second land portion. The chamfered sipe in each second land portion extends alternately from the adjacent circumferential main grooves in the tire circumferential direction.

  In the pneumatic tire according to the present invention, the arrangement of the wavy groove and the chamfer sipe is improved. As a result, according to the pneumatic tire of the present invention, wet braking performance can be improved.

FIG. 1 is a plan view showing a tread surface of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the chamfer sipe 22 shown in FIG. FIG. 3 is a cross-sectional view showing a modification of the chamfer sipe 22 shown in FIG.

  Hereinafter, embodiments of the pneumatic tire according to the present invention (basic modes and additional modes 1 to 7 shown below) will be described in detail with reference to the drawings. Note that these embodiments do not limit the present invention. In addition, the constituent elements of the above embodiment include those that can be easily replaced by those skilled in the art, or those that are substantially the same. Furthermore, various forms included in the above-described embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

[Basic form]
Below, the basic form is demonstrated about the pneumatic tire which concerns on this invention. In the following description, the tire radial direction means a direction orthogonal to the rotational axis of the pneumatic tire, the tire radial inner side is the side toward the rotational axis in the tire radial direction, and the tire radial outer side is in the tire radial direction. The side away from the rotation axis. The tire circumferential direction refers to a circumferential direction with the rotation axis as a central axis. Further, the tire width direction means a direction parallel to the rotation axis, the inner side in the tire width direction is the side toward the tire equator plane (tire equator line) in the tire width direction, and the outer side in the tire width direction is in the tire width direction. The side away from the tire equator. The tire equator plane is a plane that is orthogonal to the rotational axis of the pneumatic tire and passes through the center of the tire width of the pneumatic tire.

  FIG. 1 is a plan view showing a tread surface of a pneumatic tire according to an embodiment of the present invention. In addition, the codes | symbols E and E 'of FIG. 1 each show the grounding end of a pneumatic tire.

  The tread portion of the pneumatic tire 10 is made of a rubber material (tread rubber). Further, the surface (tread surface) of the tread portion 12 located at the outermost portion in the tire radial direction comes into contact with the road surface when the vehicle travels. As shown in FIG. 1, a tread pattern having a predetermined pattern is formed on the tread surface.

  In the example shown in FIG. 1, four circumferential main grooves 14 are symmetrically disposed on the tread surface in the tire width direction with the tire equatorial plane CL interposed therebetween. The circumferential main groove 14 has a groove width of 3 mm or more and 25 mm or less. Here, the groove width means a groove dimension (maximum value) measured in a direction perpendicular to the direction in which the groove extends. Further, the circumferential main groove 14 has a groove depth of 5 mm or more and 10 mm or less. Here, the groove depth means the groove dimension (maximum value) measured in the tire radial direction from the profile line when there is no groove.

  The circumferential main grooves 14 define a first land portion 16 at the outermost side on each side in the tire width direction, and three inner portions in the tire width direction from the first land portion 16. Two land portions 18 are defined. In the example shown in FIG. 1, the first land portion 16 and the second land portion 18 are ribs, but the present embodiment is not limited to this. For example, the first land portion 16 can be a block.

  Under this assumption, in the present embodiment, as shown in FIG. 1, a wavy groove 20 having a predetermined amplitude in the tire width direction and extending in the tire circumferential direction is formed in the second land portion 18. It is arranged. The wavy groove 20 has a groove width of 1.5 mm or more and 5 mm or less and a groove depth of 5 mm or more and 10 mm or less.

  In the present embodiment, as shown in FIG. 1, a plurality of chamfered sipes 22 are disposed in the second land portion 18.

  2 is a cross-sectional view (AA ′ cross-sectional view) of the chamfered sipe 22 shown in FIG. The chamfered sipe 22 shown in FIG. 2 is chamfered in a tapered shape, and includes a chamfered portion 22a and a sipe portion 22b.

  The dimension L1 of the chamfered portion 22a in the direction perpendicular to the extending direction of the chamfered sipe 22 can be set to 0.5 mm or more and 3.0 mm or less. The dimension D1 of the chamfered portion 22a in the tire radial direction can be 1 mm or more and 4 mm or less. The dimension L2 of the sipe part 22b in the direction perpendicular to the extending direction of the chamfered sipe 22 can be 0.3 mm or more and 2.0 mm or less. The dimension D2 of the sipe part 22b in the tire radial direction can be 2 mm or more and 5 mm or less. The depth (D1 + D2) from the top surface of the second land portion 18 to the groove bottom of the chamfered sipe 22 can be made 1.7 mm shorter than the depth of the circumferential main groove 14.

  FIG. 3 is a cross-sectional view showing a modification of the chamfer sipe 20 shown in FIG. A chamfered sipe 22 'shown in FIG. 3 is chamfered in an R shape and includes a chamfered portion 22a' and a sipe portion 22b '. The radius of curvature of the chamfered portion 22a ′ can be set to 1 mm or more and 5 mm or less. The dimensions of the sipe part 22b 'are the same as those of the sipe part 20b in FIG.

  Further, in the present embodiment, as shown in FIG. 1, the chamfered sipe 22 (22 ′) extends from the circumferential main groove 14 and terminates inside the second land portion 18. Note that the chamfered sipe 22 (22 ′) extends from the circumferential main groove 14 means that the entire chamfered sipe 22 (22 ′) (the chamfered portion 22a (22a ′) and the sipe portion 22b (22b ′)) is circumferentially main. This includes not only the case of communicating with the groove 14 but also the case where only a part of the chamfered sipe 22 (22 ′) (for example, the chamfered portion 22a (22a ′)) communicates with the circumferential main groove 14.

  In addition, in the present embodiment, as shown in FIG. 1, chamfered sipes 22 (22 ′) in the second land portions 18 alternately extend from adjacent circumferential main grooves 14 in the tire circumferential direction. doing.

  In the pneumatic tire according to the present embodiment, as shown in FIG. 1, a lug extending beyond the ground contact E (E ′) to the outermost first land portion 16 on each side in the tire width direction. Based on the groove 24 and the sipe 26 that is located between the lug grooves 24 and 24 adjacent to each other in the tire circumferential direction and is not chamfered (hereinafter may be referred to as “non-chamfered sipe”) 26 and the non-chamfered sipe 26 Inclined narrow grooves 28 located on both sides in the tire circumferential direction are disposed. The three second land portions 18 are provided with non-chamfered sipes 30. However, these members 24 to 30 are not essential components and can be optionally arranged.

(Action etc.)
In the present embodiment, the above-described corrugated groove 20 is provided in the second land portion 18 so that a drainage path extending in the tire circumferential direction can be secured (Operation 1). Further, since the edge of the land portion formed by the wavy groove 20 includes not only the tire circumferential direction component but also the tire width direction component, the resistance against the stress applied in the tire circumferential direction by the tire width direction component of this edge. Can be sufficiently exhibited (Operation 2). For this reason, these actions 1 and 2 can be combined to realize an excellent wet braking performance (effect 1).

  In the present embodiment, the second land portion 18 is provided with a plurality of chamfered sipes 22 (22 ′), so that the second land portion is compared with the case where only the non-chamfered sipes are disposed. The drainage performance can be enhanced while suppressing a decrease in the rigidity of 18. As a result, in this embodiment, the wet braking performance can be improved (Effect 2).

  Note that the chamfered sipe 22 shown in FIG. 1 (plan view) is continuously chamfered from one side in the width direction to the other side in the width direction through the end in the extending direction. Thereby, the local rigidity change of a land part can be made small especially in the extension direction edge part, generation | occurrence | production of a crack etc. can be suppressed and eventually durability performance can be improved.

  Furthermore, in this embodiment, the both ends of the chamfered sipe 22 (22 ′) are extended by extending the chamfered sipe 22 (22 ′) from the circumferential main groove 14 and terminating inside the second land portion 18. Compared with the case where it communicates with the circumferential main groove 14, the rigidity of the second land portion 18 can be increased. Moreover, compared with the case where both ends of the chamfered sipe 22 (22 ′) are terminated inside the second land portion 18, the drainage performance is improved. As a result, in this embodiment, the wet braking performance can be improved (Effect 3). When the end of the chamfered sipe 22 on the circumferential main groove 14 side is raised and only the chamfered portion 22a communicates with the circumferential main groove 14 (not shown), the rigidity of the second land portion 18 is increased. Can be further improved, and as a result, the wet braking performance can be further improved.

  In addition, in the present embodiment, the chamfered sipes 22 (22 ′) are alternately extended from the adjacent circumferential main grooves 14 in the tire circumferential direction, so that the chamfered sipes 22 (22 ′) are adjacent to each other. The circumferential main grooves 14 and 14 can be extended from different tire circumferential positions. As a result, the contact area during rolling of the tire can be made more uniform in the tire circumferential direction, and as a result, the lateral force when the tire has a slip angle can be made more uniform during rolling of the tire. it can. As a result, according to the present embodiment, the wet braking performance can be improved (Effect 4).

  As described above, the pneumatic tire according to the present embodiment can achieve the above effects 1 to 4 by improving the arrangement of the wavy grooves and the chamfered sipe. As a result, according to the pneumatic tire of the present invention, wet braking performance can be improved.

  In addition, although not shown in figure, the pneumatic tire which concerns on this Embodiment shown above has the same meridional cross-sectional shape as the conventional pneumatic tire. Here, the meridional cross-sectional shape of the pneumatic tire refers to a cross-sectional shape of the pneumatic tire that appears on a plane perpendicular to the tire equatorial plane. The pneumatic tire according to the present embodiment has a bead portion, a sidewall portion, a shoulder portion, and a tread portion from the inner side in the tire radial direction toward the outer side in a tire meridian cross-sectional view. The pneumatic tire includes, for example, a carcass layer extending from a tread portion to bead portions on both sides and wound around a pair of bead cores in a tire meridional section, and a tire radial outside of the carcass layer. The belt layer and the belt reinforcing layer are sequentially formed.

  Furthermore, the pneumatic tire of the present embodiment is subjected to normal manufacturing processes, that is, a tire material mixing process, a tire material processing process, a green tire molding process, a vulcanization process, and an inspection process after vulcanization. It is obtained through the process. When manufacturing the pneumatic tire of the present embodiment, in particular, a concave portion and a convex portion corresponding to the convex portion formed in the tread portion shown in FIG. 1 are formed on the inner wall of the vulcanizing mold. Then, vulcanization is performed using this mold. Further, the chamfered sipe may be formed by directly carving the chamfered portion on the tread surface before the inspection process after vulcanization. In this case, the chamfer sipe can be formed on the tread surface without changing the existing vulcanization mold.

[Additional form]
Next, additional modes 1 to 7 that can be optionally implemented with respect to the basic mode of the pneumatic tire according to the present invention will be described.

(Additional form 1)
In the basic form, as shown in FIG. 1, the ratio T / W between the amplitude T of the wavy groove 20 and the tire width direction dimension W of the second land portion 18 is 0.2 or more and 0.4 or less. (Additional form 1) is preferred.

  By setting the ratio T / W to be 0.2 or more, the tire width direction component can be further included in the edge of the land portion that is partitioned by the wavy groove 20. As a result, the resistance against the stress applied in the tire circumferential direction can be exhibited at a higher level, and the wet braking performance can be further improved.

  Further, by setting the ratio T / W to 0.4 or less, the rigidity of the second land portion 18 can be sufficiently ensured without excessively increasing the amplitude of the wavy groove 20. As a result, the resistance against the stress applied in the tire circumferential direction can be exhibited at a higher level, and the wet braking performance can be further improved.

(Additional form 2)
In the basic form and the form in which the additional form 1 is added to the basic form, as shown in FIG. 1, the inflection points adjacent to each other in the wavy groove 20 (for example, the inflection point P1, the inflection point P2, the inflection point). In each tire circumferential region (for example, regions R1 to R5) defined by P2 and inflection point P3,..., Inflection point P5 and inflection point P6), chamfer sipe 22 and corrugated groove 20 It is preferable that the tire is disposed in a region in the tire width direction opposite to the convex side (additional form 2). Here, the tire circumferential region refers to a specific region of the second land portion 18 in which adjacent inflection points of the chamfered sipe 22 are one end and the other end in the tire circumferential direction.

  The chamfered sipe 22 is disposed in the tire width direction region opposite to the side on which the wavy groove 20 forms a convex shape (for example, in the regions R1, R3, and R5, the left side of the wavy groove 20 in FIG. In R4, a chamfered sipe 22 is disposed on the right side of the corrugated groove 20 in FIG. 1), and the chamfered sipe 22 is disposed in a tire width direction region having a large land area among the tire circumferential regions described above. can do. As a result, in all the tire circumferential regions continuous in the tire circumferential direction, it is possible to suppress the occurrence of locations where the land portion rigidity becomes extremely low. Wear performance can be improved.

(Additional form 3)
In the basic form and the form obtained by adding at least one of the additional forms 1 and 2 to the basic form, as shown in FIG. 1, the chamfer sipe 22 does not reach the center position in the tire width direction of each second land portion 18. It is preferably terminated with (additional form 3).

  By terminating the chamfered sipe 22 without reaching the center position in the tire width direction of each second land portion 18, it is possible to prevent the groove area from becoming excessive in the second land portion 18. As a result, it is possible to suppress a decrease in the rigidity of the second land portion 18 and to improve uneven wear resistance.

(Additional form 4)
The basic form and the form obtained by adding at least one of the additional forms 1 to 3 to the basic form include at least three (four in the example shown in FIG. 1) circumferential main grooves 14 and the same circumferential main. A chamfered sipe 22 extending from the groove 14 (each of the two circumferential main grooves 14 close to the tire equatorial plane CL in the example shown in FIG. 1) to the inside of the different second land portion 18 is provided in the tire circumferential direction. It is preferred that they extend alternately (additional form 4).

  By alternately extending the chamfered sipes 22 extending from the same circumferential main groove 14 into different second land portions 18 in the tire circumferential direction, the ground contact area at the time of tire rolling can be increased over time. It can be made more uniform without being overly different. As a result, the lateral force when the slip angle is given to the tire can be made more constant during tire rolling, and as a result, the wet braking performance can be further improved. Further, by alternately extending the chamfered sipes 22 extending from the same circumferential main groove 14 into different second land portions 18 in the tire circumferential direction, the ground contact area at the time of rolling the tire is increased. It can be made more uniform in the tire circumferential direction. For this reason, the contact surface pressure with time during rolling of the tire can be made more uniform, and as a result, uneven wear resistance can be further improved.

(Additional form 5)
In the basic form and the form obtained by adding at least one of the additional forms 1 to 4 to the basic form, as shown in FIG. 1, the number of chamfered sipes 22 in each second land portion 18 is equal to each first land portion 16. Is preferably twice the number of width direction grooves 24 (additional form 5).

  By setting the number of chamfered sipes 22 in each second land portion 18 to twice the number of width direction grooves 24 in each first land portion 16, the distance between the first land portion 16 and the second land portion 18 is set. The difference in rigidity can be reduced, and consequently the uneven wear resistance performance can be improved. Further, by setting the number of chamfered sipes 22 in each second land portion 18 to be twice the number of widthwise grooves 24 in each first land portion 16, each chamfered sipe 22 increases the number of chamfered sipes 22. Edge can be formed. For this reason, the tire width direction component of these edges can further exert a resistance against the stress applied in the tire circumferential direction, and can further improve the wet braking performance.

(Additional form 6)
In the basic form and the form obtained by adding at least one of the additional forms 1 to 5 to the basic form, as shown in FIG. 1, the second land portion 18 extends from the circumferential main groove 14 and the second land. A non-chamfered sipe 30 that terminates inside the portion 18 is disposed, and the chamfered sipe 22 and the non-chamfered sipe 30 are alternately arranged in the tire circumferential direction on each side in the tire width direction of each second land portion 18. It is preferable (additional form 6).

  On each side in the tire width direction of each second land portion 18, the chamfered sipe 22 and the non-chamfered sipe 30 are alternately arranged in the tire circumferential direction, so that the land area of the tire circumferential region described above is increased. The chamfered sipe 22 can be disposed in the large tire width direction region, and the non-chamfered sipe can be disposed in the tire width direction region having a small land area. As a result, in all the tire circumferential regions continuous in the tire circumferential direction, it is possible to suppress the occurrence of locations where the land portion rigidity becomes extremely low. Wear performance can be improved.

(Additional form 7)
In the basic form and the form obtained by adding at least one of the additional forms 1 to 6 to the basic form, as shown in FIG. 1, the sipe (the chamfered sipe 22 and the non-chamfered chamfer) disposed in the second land portion 18. The extending angle θ of the sipe 30) with respect to the tire width direction is preferably 5 ° or more and 45 ° or less (additional form 7).

  By setting the extending angle θ of the sipe disposed in the second land portion 18 with respect to the tire width direction to be 5 ° or more, both the sipe adjacent to the sipe in the direction perpendicular to the extending direction of these sipe. When the land portion is separated from the road surface after the ground contact, slip deformation in the tire circumferential direction of the both land portions can be suppressed. As a result, in particular, the difference in wear between the two land portions can be suppressed, thereby improving the uneven wear resistance performance.

  In addition, by setting the extending angle θ to 45 ° or less, when both land portions adjacent to the sipe are separated from the road surface after being grounded in the direction perpendicular to the extending direction of these sipe, Slip deformation in the tire width direction of the portion can be suppressed. As a result, in particular, the difference in wear between the two land portions can be suppressed, thereby improving the uneven wear resistance performance.

  The tire size is 195 / 65R15, and the four circumferential main grooves form a first land portion on the outermost side on each side in the tire width direction and a second land portion on the inner side in the tire width direction from the first land portion. A wavy groove extending in the tire circumferential direction with a predetermined amplitude in the tire width direction is disposed in the second land portion, and a plurality of chamfered sipes disposed in the second land portion are circumferential in the second land portion. Example 1 that extends from the main groove and terminates in the second land portion, and chamfered sipes in the second land portions alternately extend from adjacent circumferential main grooves in the tire circumferential direction. To 8 pneumatic tires were produced. The various conditions of each tread pattern of the pneumatic tires of Examples 1 to 8 are as shown in Table 1 below.

  On the other hand, the tread pattern is the same as that of the pneumatic tire of Example 1 except that the tire size is 195 / 65R15 and a straight groove is provided at the center position in the tire width direction of each second land portion instead of the wavy groove. A pneumatic tire of a conventional example having

  Each of the test tires of Example 1 to Example 8 and the conventional example manufactured in this manner was assembled to a 15 × 6J rim at 220 kPa, and mounted on a sedan type vehicle (front engine / front drive system) with a displacement of 1800 CC, The wet braking performance and uneven wear resistance performance were evaluated.

(Wet braking performance)
On a wet road surface (water depth of 1 mm), an index evaluation was performed using a conventional example as a reference (100) by measuring a braking distance from a state where the vehicle traveled at a speed of 100 km / h. This evaluation shows that wet braking performance is excellent, so that a numerical value is large.

(Uneven wear resistance)
Heel and toe wear after the vehicle was traveled 50000 km was measured. And based on this measurement result, the index evaluation which made the conventional example the reference | standard (100) was performed. This evaluation shows that the higher the index, the higher the uneven wear resistance performance.

  According to Table 1, all of the pneumatic tires of Examples 1 to 8 belonging to the technical scope of the present invention (with improvements in the arrangement of the wavy grooves and the chamfered sipe) of the present invention. It can be seen that at least the wet braking performance is superior to the conventional pneumatic tire which does not belong to the technical scope.

  The present invention includes the following aspects.

(1) Provided with a plurality of circumferential main grooves, and by the circumferential main grooves, the outermost first land portion on each side in the tire width direction and the second land portion on the inner side in the tire width direction from the first land portion In the pneumatic tire formed with a plurality of wavy grooves extending in the tire circumferential direction and having a predetermined amplitude in the tire width direction in the second land portion, a plurality of grooves are disposed in the second land portion. A chamfered sipe is provided, the chamfered sipe extends from the circumferential main groove and terminates inside the second land portion, and the chamfered sipe in each second land portion is adjacent in the tire circumferential direction. A pneumatic tire characterized by alternately extending from the circumferential main groove.

(2) The air according to (1), wherein a ratio T / W of the amplitude T of the wavy groove and the tire width direction dimension W of the second land portion is 0.2 or more and 0.4 or less. Enter tire.

(3) In each tire circumferential region defined by adjacent inflection points of the wavy groove, the chamfer sipe is disposed in a tire width direction region opposite to the side where the wavy groove forms a convex shape. The pneumatic tire according to (1) or (2) above.

(4) The pneumatic tire according to any one of (1) to (3), wherein the chamfered sipe terminates without reaching the center position in the tire width direction of each second land portion.

(5) The chamfering sipes provided with at least three circumferential main grooves and extending from the same circumferential main groove into different second land portions alternately extend in the tire circumferential direction, The pneumatic tire according to any one of (1) to (4).

(6) The air according to any one of (1) to (5), wherein the number of chamfered sipes in each second land portion is twice the number of widthwise grooves in each first land portion. Enter tire.

(7) A non-chamfered sipe extending from the circumferential main groove and terminating inside the second land portion is disposed in the second land portion, and the tire width direction of each second land portion The pneumatic tire according to any one of (1) to (6), wherein on each side, the chamfered sipe and the non-chamfered sipe are alternately arranged in a tire circumferential direction.

(8) The extending angle θ of the sipe disposed in the second land portion with respect to the tire width direction is not less than 5 ° and not more than 45 °, in any one of (1) to (7) above The described pneumatic tire.

DESCRIPTION OF SYMBOLS 10 Pneumatic tire 12 Tread part 14 Circumferential main groove 16 1st land part 18 2nd land part 20 Wavy groove 22, 22 'Chamfering sipe 22a, 22a' Chamfering part 22b, 22b 'Sipe part 24 Lag groove 26, 30 Non Chamfer sipe 28 Inclined narrow groove CL Tire equatorial plane D1 Dimensions of chamfer 22a in the tire radial direction D2 Dimensions of sipe 22b in the tire radial direction E, E 'Grounding edge L1 Chamfer in a direction perpendicular to the extending direction of chamfer sipe 22 Size of portion 22a L2 Size of sipe portion 22b in a direction perpendicular to the extending direction of chamfered sipe 22 P1, P2, P3, P4, P5, P6 Inflection point R1, R2, R3, R4, R5 region

Claims (8)

A plurality of circumferential main grooves are provided, and the circumferential main grooves define first outermost land portions on each side in the tire width direction and second land portions on the inner side in the tire width direction from the first land portions. In the formed pneumatic tire,
A wavy groove extending in the tire circumferential direction with a predetermined amplitude in the tire width direction is disposed in the second land portion,
A plurality of chamfer sipes are disposed on the second land portion,
The chamfer sipe extends from the circumferential main groove and terminates inside the second land portion;
The pneumatic tire according to claim 1, wherein the chamfered sipe in each second land portion alternately extends from the adjacent circumferential main grooves in the tire circumferential direction.   2. The pneumatic tire according to claim 1, wherein a ratio T / W of an amplitude T of the wavy groove and a tire width direction dimension W of the second land portion is 0.2 or more and 0.4 or less.   In each tire circumferential region defined by adjacent inflection points of the wavy groove, the chamfer sipe is disposed in a tire width direction region on the opposite side to the side on which the wavy groove forms a convex shape. The pneumatic tire according to claim 1 or 2.   The pneumatic tire according to any one of claims 1 to 3, wherein the chamfered sipe terminates without reaching the center position in the tire width direction of each second land portion.   The chamfering sipes having at least three circumferential main grooves and extending from the same circumferential main groove into different second land portions alternately extend in the tire circumferential direction. The pneumatic tire according to any one of 4.   The pneumatic tire according to any one of claims 1 to 5, wherein the number of chamfered sipes in each second land portion is twice the number of width direction grooves in each first land portion.   A non-chamfered sipe extending from the circumferential main groove and terminating inside the second land portion is disposed in the second land portion, and on each side in the tire width direction of each second land portion. The pneumatic tire according to any one of claims 1 to 6, wherein the chamfered sipe and the non-chamfered sipe are alternately arranged in a tire circumferential direction.   The pneumatic tire according to any one of claims 1 to 7, wherein an extension angle θ of a sipe disposed in the second land portion with respect to a tire width direction is 5 ° or more and 45 ° or less.

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