JP2020147170A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire that is improved in wet driving stability performance and passing noise performance.SOLUTION: A pneumatic tire includes sipes (16a, 16b) and a lug groove (17) in shoulder land parts (S1, S2), where a first sipe (16a) extending while being inclined relative to a tire width direction and a second sipe (16b) extending in a direction different from the first sipe are formed in the shoulder land parts.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pneumatic tire having improved wet steering stability performance and passing noise performance.

In recent years, tire noise regulations have tended to be tightened, and therefore, a technique for improving noise performance while maintaining steering stability performance and wet performance (for example, due to lateral acceleration of front wheels) has been proposed (Patent Document 1). ).

Japanese Patent No. 5947824

Patent Document 1 describes a fully open sipe in which the first middle sipe communicates from the center main groove to the shoulder main groove, and a first semi-open in which one end communicates with the center main groove and the other end terminates in the first middle land portion. Includes a sipe and a second semi-open sipe with one end communicating with the shoulder main groove and the other end terminating within the first middle land area, including full open sipe, first semi-open sipe, and second semi-open sipe. Pneumatic tires, each tilted in the same direction, are disclosed. With such tires, it is possible to improve noise performance while maintaining steering stability and wet performance based on improving the shapes of grooves and sipes provided in the middle land area and shoulder land area. Has been done.

In Patent Document 1, for example, referring to FIG. 1, each of the first shoulder land portion 31 and the second shoulder land portion 32 has a substantially arc-shaped first shoulder lateral groove 33 and a third, which are convex on one side in the tire circumferential direction. A plurality of 2-shoulder lateral grooves 34 are provided. The extending direction of these grooves is limited to the tire width direction, and the grooves exist only outside the central region of the land portions 31 and 32 in the tire width direction. Therefore, it cannot be said that the drainage performance is necessarily high, especially from the viewpoint that the drainage interlocking with the shoulder main grooves 3 and 3 is inferior in the inner region in the tire width direction of the land portions 31 and 32, and eventually the wet steering stability performance. Can be improved.

Further, it is conceivable to further provide a groove (including a groove extending in the tire circumferential direction and a groove extending in the tire width direction) in each of the above shoulder land portions, but in that case, a newly added groove is considered. As a result, passing noise may be further generated, and as a result, excellent passing noise performance may not be realized.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pneumatic tire having improved wet steering stability performance without deteriorating passing noise performance.

The pneumatic tire according to the present invention is provided with at least two circumferential main grooves on the tread surface, and is a tire on each side of the tire equatorial plane in the tire width direction rather than the outermost circumferential main groove in the tire width direction. A shoulder land portion on the outer side in the width direction and a center land portion on the inner side in the tire width direction with respect to the circumferential main groove located on the outermost side in the tire width direction are divided into sections, and a sipe and a lug groove are provided on the shoulder land portion. The lug groove communicates with the main groove in the circumferential direction, and in the shoulder land portion, the first sipe extending in an inclined direction with respect to the tire width direction and the first sipe in a direction different from the first sipe. A second extending sipe is formed.

In the pneumatic tire according to the present invention, improvements have been made to the mode of forming sipes and grooves in the land portion of the shoulder. As a result, according to the pneumatic tire according to the present invention, the wet steering stability performance can be improved without deteriorating the passing noise performance.

FIG. 1 is a plan view showing the tread surface of the pneumatic tire of the present embodiment. FIG. 2 is a plan view showing a tread surface of a modified example of the pneumatic tire shown in FIG.

Hereinafter, embodiments of the pneumatic tire according to the present invention (basic and additional embodiments 1 to 9 shown below) will be described in detail with reference to the drawings. It should be noted that these embodiments do not limit the present invention. In addition, the components of the above-described embodiment include those that can be easily replaced by those skilled in the art, or those that are substantially the same. Further, various embodiments included in the above-described embodiments can be arbitrarily combined within a range that will be obvious to those skilled in the art.

[Basic form]
The basic form of the pneumatic tire according to the present invention will be described below.

In the following description, the tire radial direction means a direction orthogonal to the rotation axis of the pneumatic tire, the inner side in the tire radial direction is the side toward the rotation axis in the tire radial direction, and the outer side in the tire radial direction is the tire radial direction. The side away from the axis of rotation. Further, the tire circumferential direction refers to a circumferential direction centered on the rotation axis. Further, the tire width direction means a direction parallel to the above rotation axis, the inside in the tire width direction is the side toward the tire equatorial plane CL (tire equatorial line) in the tire width direction, and the outside in the tire width direction is the tire width direction. Refers to the side away from the tire equatorial plane CL. The tire equatorial plane CL is a plane that is orthogonal to the rotation 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. The reference numeral CL in FIG. 1 indicates the tire equatorial plane. Further, the tread pattern shown in FIG. 1 is a pattern symmetrical between both sides of the tire equatorial plane CL in the tire width direction, but the pneumatic tire of the present embodiment is symmetrical between both sides of the tire equatorial plane CL in the tire width direction. Not limited to tire patterns, but also includes asymmetric patterns.

The tread portion 10 of the pneumatic tire of the present embodiment is made of a rubber material (tread rubber). The surface of the tread portion 10 (tread surface 12) located on the outermost side in the tire radial direction comes into contact with the road surface when the vehicle is running. Further, as shown in FIG. 1, a tread pattern having a predetermined pattern described in detail below is formed on the tread surface 12.

As shown in FIG. 1, the tread surface 12 is formed with at least two circumferential main grooves extending in the tire circumferential direction (three circumferential main grooves 14a, 14b, 14c as shown in the figure). In the present embodiment, the width of the circumferential main groove is 5 to 15 mm, and the depth of the circumferential main groove is 4 to 8 mm.

Due to the formation of the circumferential main groove 14, the tread surface 12 has a circumferential main groove (as shown in FIG. 1) located on the outermost side in the tire width direction on each side of the tire equatorial plane CL in the tire width direction. The shoulder land portions S1 and S2 outside the tire width direction from the circumferential main grooves 14a and 14c) and the center land portions C1 and C2 inside the tire width direction from the circumferential main grooves 14a and 14c are partitioned. There is.

Under the above premise, in the present embodiment, as shown in FIG. 1, the shoulder land portions S1 and S2 are provided with sipes 16a and 16b and a lug groove 17. Specifically, the shoulder land portions S1 and S2 include a first sipe 16a extending in an inclined direction with respect to the tire width direction, a second sipe 16b extending in the tire circumferential direction, and a main sipe in the circumferential direction. A lug groove 17 that communicates with the grooves 14a and 14c and extends so as to be inclined with respect to the tire width direction is formed. In the example shown in the figure, the second sipe 16b communicates with both the first sipe 16a and the lug groove 17.

Further, in the shoulder land portions S1 and S2, first sipes 16a, second sipes 16b, and lug grooves 17 are formed at equal intervals in the tire circumferential direction, respectively. Further, the two second sipes 16b and 16b extending from the one lug groove 17 are formed at different positions in the tire width direction.

Here, the first sipe 16a may be linear or curved as shown in FIG. Regardless of the shape of the first sipe 16a, the inclination of the straight line connecting both end points thereof can be 55 ° or less with respect to the tire width direction. The inclination defined in the present embodiment means an acute angle or a right angle with the reference direction (for example, the tire width direction).

Further, the second sipe 16b may be linear or curved as shown in FIG. Regardless of the shape of the second sipe 16b, the inclination angle of the straight line connecting both end points with respect to the tire width direction can be 60 ° or more and 90 ° or less.

Further, the lug groove 17 may be linear or curved as shown in FIG. Regardless of the shape of the lug groove 17, the inclination angle of the straight line connecting both end points with respect to the tire width direction can be set to 0 ° or more and 45 ° or less.

On the other hand, as shown in FIG. 1, the center land portion C1 (C2) has a third sipe 16c communicating with both the circumferential main grooves 14a and 14b (14b, 14c) on both sides, and a third sipe 16c. A fourth sipe 16d extending from the sipe 16c to one side in the tire circumferential direction and terminating in the land portion is formed. In the present embodiment, the third sipe 16c and the fourth sipe 16d are formed at equal intervals in the tire circumferential direction, respectively. In addition to the sipes 16c and 16d shown in FIG. 1, the center land portion C1 (C2) has a groove (for example, a groove having a groove width and a groove depth smaller than those of the circumferential main grooves 14a to 14c) as needed. (The extending direction and shape are arbitrary), and other sipes can be formed.

The third sipe 16c may be linear or curved as shown in FIG. Regardless of the shape of the third sipe 16c, the inclination of the straight line connecting both end points thereof can be 40 ° or less with respect to the tire width direction.

The fourth sipe 16d may be linear or curved as shown in FIG. Regardless of the shape of the fourth sipe 16d, the inclination of the straight line connecting both end points thereof can be 45 ° or more and 90 ° or less with respect to the tire width direction.

In the present embodiment, the widths of the sipes 16a to 16d are 0.2 to 2 mm, and the depths of the sipes 16a to 16d are 1 to 8 mm.

(Action, etc.)
Conventionally, a plurality of substantially arc-shaped lug grooves that are convex on one side in the tire circumferential direction are provided near the ground contact end of the shoulder land portion, and these lug grooves are the maximum width grooves extending in the tire circumferential direction. In many cases, both ends of the tire were terminated within the land without communication. In the pneumatic tire of the present embodiment, since the lug groove 17 communicates with the circumferential main grooves 14a and 14c, the circumferential main grooves 14a and 14c in the inner region of the shoulder land portions S1 and S2 in the tire width direction in particular. Due to the drainage interlocking between the tire and the lug groove 17, excellent drainage performance can be realized, and by extension, excellent wet steering stability performance can be realized (action 1).

Further, conventionally, since a plurality of substantially arc-shaped lug grooves that are convex on one side in the tire circumferential direction are provided near the ground contact end of the shoulder land portion, there are many places where passing noise is generated. It was a cause of not being able to achieve excellent passing noise performance. In the pneumatic tire of the present embodiment, the groove area of the lug grooves 17 provided on the shoulder land portions S1 and S2 is about the same as that of the conventional pneumatic tire, so that the generation of passing noise is about the same as the conventional one. It can be suppressed. (Action 2). In the present embodiment, the number of lug grooves 17 is 40 or more and 85 or less in the tire circumferential direction.

Therefore, according to the pneumatic tire of the present embodiment, excellent wet steering stability performance can be realized by the above action 1 without deteriorating the passing noise performance by the above action 2.

Although not shown, the pneumatic tire according to the present 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 means the cross-sectional shape of the pneumatic tire that appears on a plane perpendicular to the equatorial plane of the tire. The pneumatic tire of the present embodiment has a bead portion, a sidewall portion, a shoulder portion, and a tread portion from the inside to the outside in the tire radial direction in a cross-sectional view of the tire meridian. The pneumatic tire has, for example, a carcass layer extending from the tread portion to the bead portions on both sides and wound around a pair of bead cores in a cross-sectional view of the tire meridian, and the outer side of the carcus layer in the tire radial direction. A belt layer and a belt reinforcing layer, which are sequentially formed in the tire, are provided.

Further, the pneumatic tire of the present embodiment undergoes each of the usual manufacturing processes, that is, a tire material mixing process, a tire material processing process, a green tire molding process, a vulcanization process, an inspection process after vulcanization, and the like. It is obtained through the process. In the case of manufacturing the pneumatic tire of the present embodiment, in particular, on the inner wall of the vulcanization die, for example, a sipe, a lug groove and a convex portion corresponding to a land portion formed in the tread portion shown in FIG. And a recess is formed, and vulcanization is performed using this mold.

[Additional form]
Next, additional embodiments 1 to 9 which can be optionally implemented with respect to the basic embodiment of the pneumatic tire according to the present invention will be described.

(Additional form 1)
In the basic form, it is preferable that the inclination angle θ1 of the first sipe 16a shown in FIG. 1 with respect to the tire width direction is 45 ° or less (additional form 1). When the tire width direction dimension of the first sipe 16a from the circumferential main groove 14a (14c) to the end position in the land portion is kept constant without being excessively increased in order to secure the rigidity of the shoulder land portions S1 and S2. The actual size of the first sipe 16a becomes smaller as the inclination angle θ1 becomes smaller. In the present embodiment, since the inclination angle θ1 is 45 ° or less, the actual size of the first sipe 16a does not become excessively large, the surface area of the first sipe 16a can be reduced, and thus the passing noise performance. Can be further enhanced.

Further, in the present embodiment, since the inclination angle θ1 is set to 45 ° or less, the surface area of the first sipe 16a can be reduced as described above. Therefore, the rigidity of the shoulder land portions S1 and S2 can be further increased to further enhance the wet steering stability performance.

When the tilt angle θ1 is 40 ° or less, the above effects are more preferable because they are produced at a higher level, and when the tilt angle θ1 is 35 ° or less, the above effects are at a higher level. It is extremely preferable because it is played.

(Additional form 2)
In the basic form or the form in which the additional form 1 is added to the basic form, the inclination angle θ2 of the second sipe 16b shown in FIG. 1 with respect to the tire width direction is 45 ° or more and 90 ° or less (additional form 2). Is preferable. In the example shown in FIG. 1, the second sipe 16b extends in the tire circumferential direction, and the inclination angle θ2 is 90 °.

In order to ensure the rigidity of the shoulder land portions S1 and S2, when the tire circumferential dimension of the second sipe 16b from the first sipe 16a to the lug groove 17 is kept constant without being excessively increased, it is inclined. When the angle θ2 is 90 °, the actual size of the second sipe 16b becomes the smallest, and when it is less than 45 °, the actual size becomes excessively large. In the present embodiment, since the inclination angle θ2 is 45 ° or more and 90 ° or less, the actual size of the second sipe 16b does not become excessively large, and the surface area of the second sipe 16b can be reduced. The passing noise performance can be further improved.

Further, in the present embodiment, since the inclination angle θ2 is set to 45 ° or more and 90 ° or less, the surface area of the second sipe 16b can be reduced as described above. Therefore, the rigidity of the shoulder land portions S1 and S2 can be further increased to further enhance the wet steering stability performance.

It is more preferable that the inclination angle θ2 is 50 ° or more and 90 ° or less because the above effects are exhibited at a high level, and the above effect is more preferable when the inclination angle θ2 is 55 ° or more and 90 ° or less. Is played at a higher level, which is extremely preferable.

(Additional form 3)
In the basic form or a form in which at least one of the additional form 1 and the additional form 2 is added to the basic form, a region of 30% or more and 70% or less of the tire width direction region of the first sipe 16a shown in FIG. It is preferable that the formation region of the second sipe 16b is present (additional form 3). Here, the formed region of the second sipe 16b means the entire formed region, and even a part of the region that deviates from the above range is not included in the present embodiment. ..

In the example shown in FIG. 1, the tire width direction region of the first sipe 16a is represented by reference numeral L1. Here, the innermost position in the tire width direction is set to the 0% position, and the outermost position in the tire width direction is set to the 100% position. In the present embodiment, the second sipe 16b is formed in the region from the 30% position to the 70% position. That is, the second sipe 16b is not excessively brought close to the circumferential main groove 14a (14c), and the second sipe 16b is also excessively brought close to the ground contact end at the outermost position in the tire width direction in the region indicated by reference numeral L1. Not. As a result, the rigidity in the vicinity of the circumferential main grooves 14a (14c) of the shoulder land portions S1 and S2 can be increased, the rigidity in the vicinity of the ground contact end can be increased, and the wet steering stability performance can be further enhanced. ..

When the formation region of the second sipe 16b exists in the region of 35% or more and 65% or less of the tire width direction region of the first sipe 16a, the above effects are exhibited at a high level. preferable. Further, when the formation region of the second sipe 16b exists in the region of 40% or more and 60% or less of the tire width direction region of the first sipe 16a, the above effects are exhibited at a higher level. Very preferable.

(Additional form 4)
In the basic form or a form in which at least one of the additional forms 1 to 3 is added to the basic form, the tire circumferential dimension of the second sipe 16b is 35 of the pitch length of the first sipe 16a. It is preferably% or more and 65% or less (additional form 4).

In the example shown in FIG. 1, the tire circumferential dimension of the second sipe 16b is represented by the reference numeral L2, and the pitch length of the first sipe 16a is represented by the reference numeral P1. In the present embodiment, the surface area of the second sipe 16b can be sufficiently secured by setting the tire circumferential dimension of the second sipe 16b to 35% or more of the pitch length of the first sipe 16a. it can. Therefore, the drainage performance of the shoulder land portions S1 and S2 can be further enhanced, and the wet steering stability performance can be further enhanced.

On the other hand, by setting the tire circumferential dimension of the second sipe 16b to 65% or less of the pitch length of the first sipe 16a, it is possible to prevent the surface area of the second sipe 16b from becoming excessively large. As a result, the passing noise performance can be further improved.

By setting the tire circumferential dimension of the second sipe 16b to 37% or more and 62% or less of the pitch length of the first sipe 16a, the above effects can be achieved at a higher level, and 35%. By setting the content to 60% or less, the above effects can be achieved at extremely high levels.

(Additional form 5)
FIG. 2 is a plan view showing a tread surface of a modified example of the pneumatic tire shown in FIG. In the basic form or a form in which at least one of the additional forms 1 to 4 is added to the basic form, at least two second sipes (the same) from each of the first sipes 16a shown in FIG. In the example shown in the figure, it is preferable that the two sipes 16b, 16b) extend to the same side in the tire circumferential direction (additional form 5).

By communicating at least two second sipes with each of the first sipes 16a shown in FIG. 2, the drainage performance can be further improved. Further, by extending each of the second sipes to the same side in the tire circumferential direction with respect to the first sipes 16a, the drainage performance can be efficiently improved especially for the tire whose rotation direction is specified. Can be done. As described above, according to the type of pneumatic tire shown in FIG. 2, the wet steering stability performance can be further improved.

(Additional form 6)
In the basic form or a form in which at least one of the additional forms 1 to 5 is added to the basic form, the tires are located on both sides in the tire width direction in the center land portions C1 and C2 shown in FIG. 1 or FIG. A third sipe 16c and a third sipe 16c that communicate with at least one of the main grooves 14a and 14b (14b, 14c) in the circumferential direction (both in both figures) and have an inclination angle θ3 with respect to the tire width direction of 45 ° or more and less than 90 °. It is preferable that a fourth sipe 16d that communicates with the sipe 16c and extends in the tire circumferential direction is formed (additional form 6).

The third sipe 16c communicates with the circumferential main groove at at least one end thereof, and its maximum dimension in the tire width direction is the dimension between the two circumferential main grooves. When the tire width direction dimension of the third sipe 16c is constant, the actual size of the third sipe 16c increases as the inclination angle θ3 increases. In the present embodiment, since the inclination angle θ3 is 45 ° or more, the actual size of the third sipe 16c can be sufficiently secured, the surface area of the third sipe 16c can be increased, and the wet steering stability performance can be increased. Can be further enhanced. When the inclination angle θ3 is 90 °, the actual size of the third sipe 16c is ∞. Therefore, in the present embodiment, the inclination angle θ3 is set to less than 90 °.

When the inclination angle θ3 is 50 ° or more, the above effect can be achieved at a higher level, and when it is 55% or more, the above effect can be achieved at an extremely high level.

(Additional forms 7, 8)
In the basic form or a form in which at least one of the additional forms 1 to 6 is added to the basic form, the circumferential main grooves 14a and 14c shown in FIG. 1 or 2 are communicated with the first sipe 16a. A recess 18 is formed in the portion (additional form 7), and / or, in the communicating portion between the circumferential main grooves 14a, 14b, 14c and the third sipe 16c shown in FIG. 1 or FIG. It is preferable that the recess 20 is formed (additional form 8).

By forming the recesses 18 and 20, the drainage performance can be improved. Further, by forming the recesses 18 and 20, it is possible to suppress the baldness of the land portion in the vicinity of the communication point between the circumferential main grooves 14a and 14c and the first sipe 16a when the vehicle is traveling. As described above, according to the present embodiment, it is possible to make the ground pressure uniform, improve the uneven wear resistance performance, and eventually realize excellent wet steering stability performance for a long period of time.

(Additional form 9)
In the basic form or a form in which at least one of the additional form 1 to the additional form 8 is added to the basic form, the directional pattern is preferable (additional form 9). Here, the directional pattern refers to a pattern in which the rotation direction during vehicle travel is specified. For example, in the example shown in FIG. 1, since there are two extending directions of the second sipe 16b from the first sipe 16a, the rotation direction is not specified and the pattern is non-directional. On the other hand, in the example shown in FIG. 2, since there is only one extending direction of the second sipe 16b from the first sipe 16a, the rotation direction is specified and it is a directional pattern.

In the tire shown in FIG. 2, if the side of the second sipe 16b communicating with the first sipe 16a is used as the stepping side and the lug groove side of the second sipe 16b is used as the kicking side, the tire shown in FIG. The drainage performance is significantly higher than when using the tire, and it is possible to realize better drainage performance and, by extension, wet steering stability performance.

The tire size is 185 / 65R15, and the circumferential main grooves 14a to 14c, the first sipe 16a, the second sipe 16b, the third sipe 16c, the fourth sipe 16d, and the lug groove 17 shown in FIG. The pneumatic tires of Invention Examples 1 to 9 satisfying each condition shown in Tables 1 to 3 were produced. On the other hand, the tire size is 185 / 65R15, and the circumferential main grooves 14a to 14c, the first sipe 16a, the second sipe 16b, the third sipe 16c, and the fourth sipe 16d shown in FIG. In addition, the shoulder land portions S1 and S2 have lug grooves 33 and 34 as shown in FIG. 1 of Patent Document 1 (lug grooves that do not communicate with the circumferential main groove referred to in the present application and extend completely to the ground contact end. ), And a conventional pneumatic tire satisfying each condition shown in Tables 1 to 3 was produced.

The terms in each condition shown in Tables 1 to 3 (shoulder land parts S1, S2, center land parts C1, C2, first sipe 16a, second sipe 16b, third sipe 16c, fourth sipe). 16d, lug groove 17, recesses 18, 20, L1, L2, P1, θ1 to θ3) all indicate constituent members and dimensions indicated by the respective reference numerals shown in FIGS. 1 or 2.

Then, each test tire (each embodiment and a conventional example) was mounted on a rim of size 5.5J, and the air pressure was set to 210 kPa, and these were mounted on a front engine / front drive type vehicle having a displacement of 1500 CC. For all these test tires, the passing noise performance and wet steering stability performance were evaluated as follows. These results are shown in Tables 1 to 3.

(Passing noise performance)
The passing noise performance was evaluated according to the tire noise test method specified in ECE R117-02 (ECE Regulation No. 117 Revision 2). In this test, the maximum noise value (dB) in the noise measurement section when the test vehicle was run sufficiently before the noise measurement section, the engine was stopped before the section, and the test vehicle was coasted was ± ± with respect to the reference speed. The speed range of 10 km / hour was measured at a plurality of speeds divided into 8 or more at approximately equal intervals, and the average was taken as the (outside the vehicle) passing noise. The maximum noise value dB is the sound measured through the A-weighting frequency correction circuit using a stationary microphone installed at a height of 7.5 m from the center line to the side and 1.2 m from the road surface at the midpoint in the noise measurement section. The pressure [dB (A)]. The sound pressures shown in Tables 1 to 3 were indexed with the conventional example of 100. In Tables 1 to 3, the higher each value is, the lower the sound pressure is, that is, the higher the passing noise performance is.

(Wet steering stability performance)
For the wet steering stability performance, the average lateral acceleration when traveling five laps at a limit speed on a turning circuit having a radius of 30 m on a wet road surface at a water depth of about 1 mm at an outdoor tire test site was evaluated. The average lateral acceleration shown in Tables 1 to 3 was an index evaluation with the conventional example of 100. In Tables 1 to 3, the higher each value is, the higher the average lateral acceleration is, that is, the higher the wet steering stability performance is.

According to Tables 1 to 3, a sipe and a lug groove are provided in the land portion of the shoulder, and the first sipe extending in the land portion of the shoulder at an angle with respect to the tire width direction and extending in the tire circumferential direction. With respect to the pneumatic tires of Invention Examples 1 to 9, which belong to the technical scope of the present invention, in which the second sipe is formed, none of them belong to the technical scope of the present invention. It can be seen that the passing noise performance and the wet steering stability performance are improved in a well-balanced manner with respect to the tires.

10 Tread part 12 Tread surface 14a, 14b, 14c Circumferential main groove 16a, 16b, 16c, 16d Sipe 17 Rug groove 18, 20 Recess C1, C2 Center land CL Tire Equator surface L1 Tire width direction of first sipe 16a Area L2 Tire circumferential dimensions of the second sipe 16b P1 Pitch length of the first sipe 16a S1, S2 Shoulder land θ1 Tilt angle of the first sipe 16a with respect to the tire width direction θ2 Tire width of the second sipe 16b Tilt angle with respect to direction θ3 Tilt angle of the third sipe 16c with respect to the tire width direction

Claims (10)

The tread surface is provided with at least two circumferential main grooves, and on each side of the tire equatorial plane in the tire width direction, a shoulder land portion outside the tire width direction from the outermost circumferential main groove in the tire width direction. It is a pneumatic tire in which the center land portion inside the tire width direction is partitioned from the circumferential main groove located on the outermost side in the tire width direction.
A sipe and a lug groove are provided on the shoulder land.
The lug groove communicates with the circumferential main groove and
A feature of the shoulder land portion is that a first sipe extending in an inclined direction with respect to the tire width direction and a second sipe extending in a direction different from the first sipe are formed. Pneumatic tires. The pneumatic tire according to claim 1, wherein the inclination angle of the first sipe with respect to the tire width direction is 45 ° or less. The pneumatic tire according to claim 1 or 2, wherein the inclination angle of the second sipe with respect to the tire width direction is 45 ° or more and 90 ° or less. The pneumatic tire according to any one of claims 1 to 3, wherein the second sipe is formed in a region of 30% or more and 70% or less of the tire width direction region of the first sipe. The pneumatic tire according to any one of claims 1 to 4, wherein the tire circumferential dimension of the second sipe is 35% or more and 65% or less of the pitch length of the first sipe. The pneumatic tire according to any one of claims 1 to 5, wherein at least two of the second sipes extend from each of the first sipes to the same side in the tire circumferential direction. In the center land portion, a third sipe that communicates with at least one of the circumferential main grooves located on both sides in the tire width direction and has an inclination angle of 45 ° or more and 90 ° or less with respect to the tire width direction, and the third sipe. The pneumatic tire according to any one of claims 1 to 6, wherein a fourth sipe that communicates with the sipe and extends in the tire circumferential direction is formed. The pneumatic tire according to any one of claims 1 to 7, wherein a recess is formed in a portion where the circumferential main groove and the first sipe communicate with each other. The pneumatic tire according to claim 7 or 8, wherein a recess is formed in a portion where the circumferential main groove and the third sipe communicate with each other. The pneumatic tire according to any one of claims 1 to 9, which is a directional pattern.