JP6450140B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire.

  Conventionally, in order to improve the drainage of a tire, a plurality of grooves are provided on the tread surface of the tire. However, when the number of grooves is increased, the drainage performance is improved, but the rigidity of the land portion is lowered, and there is a problem that steering stability and braking performance are lowered. On the other hand, if the number of grooves is too small, the rigidity of the land portion will be improved and the handling stability and braking performance will be improved, but the drainage will be reduced and the turning performance and braking performance will be reduced in rainy weather. There is a problem. Thus, it is generally difficult to make drainage and steering stability compatible with each other.

  On the other hand, a method has been proposed in which inclined grooves having different groove widths are arranged in communication with the tread surface to achieve both drainability and land rigidity (for example, see Patent Document 1).

JP 2013-173521 A

  However, in the technique described in Patent Document 1, the response at the initial stage of steering is insufficient among the steering stability, the response of the vehicle is slow even when the steering wheel is started, and the sporty feeling is inferior, and the response of the vehicle is slow. For this reason, there has been a problem that the steering stability of the vehicle is deteriorated by turning the steering wheel too much.

  The present invention is intended to solve the above-described problems, and an object of the present invention is to provide a pneumatic tire that achieves both drainage and responsiveness at the initial stage of steering.

The gist configuration of the present invention is as follows.
The pneumatic tire of the present invention has a plurality of circumferential main grooves on the tread surface, and a plurality of land portions are defined by the plurality of circumferential main grooves and tread ends.
Two land portions adjacent to the outer side in the tread width direction of the circumferential main groove arranged at a position closest to the tire equator plane have a plurality of inclined grooves extending incline in the tread width direction,
The inclined groove is formed by communicating a first groove and a second groove having a groove width smaller than the groove width of the first groove,
The first groove communicates with the circumferential main groove,
The inclined groove terminates in the land portion.
According to this configuration, it is possible to achieve both drainage and responsiveness at the initial stage of steering.

  Here, “groove width” means the opening width with respect to the tread tread when the tire is mounted on the applicable rim, filled with the specified internal pressure, and is in an unloaded state. If the groove width is not constant, the maximum width It shall be said. Further, “groove depth” and “sipe depth”, which will be described later, refer to the maximum depth of grooves and sipes in the same state.

  “Applicable rim” is an industrial standard effective in the area where tires are produced and used. In Japan, JATMA (Japan Automobile Tire Association) YEAR BOOK is used. In Europe, ETRTO (European Tire and Rim Technical Organization) is used. STANDARD MANUAL, in the United States, refers to a rim defined by TRA (THE TIRE and RIM ASSOCATION INC.) YEAR BOOK, etc. Further, the “specified internal pressure” refers to an air pressure (maximum air pressure) corresponding to a tire maximum load capacity of a standard such as JATMA when a tire is mounted on an applicable rim and a tire of an applicable size.

Here, the pneumatic tire of the present invention has a circumferential sipe extending in the tread circumferential direction at the end of the second groove opposite to the side communicating with the first groove. ,
It is preferable that each of both ends of the circumferential sipe has a width direction sipe extending in the tread width direction.
According to this configuration, the braking performance can be improved.

In the pneumatic tire of the present invention, the width sipe communicates with the circumferential main groove,
It is preferable that the said width direction sipe is inclined and extended with respect to the tread width direction.
According to this configuration, it is possible to improve noise performance while further improving drainage.

Furthermore, in the pneumatic tire of the present invention, it is preferable that the circumferential sipe extends while being inclined with respect to the tread circumferential direction.
According to this configuration, drainage can be further enhanced.

Furthermore, in the pneumatic tire of the present invention, at the end of the second groove opposite to the side communicating with the first groove, there is a circumferential sipe extending in the tread circumferential direction,
A widthwise sipe extending in the tread width direction is formed at one end of the circumferential sipe in the tread circumferential direction, and a widthwise thin line extending in the tread width direction is disposed at the other end of the circumferential sipe in the tread circumferential direction. It is preferable to have a groove.
According to this configuration, drainage can be further enhanced.

  According to the present invention, it is possible to provide a pneumatic tire that achieves both drainage and responsiveness at the initial stage of steering.

It is an expanded view which shows the tread pattern concerning one Embodiment of this invention. It is an expanded view which shows the tread pattern concerning other embodiment of this invention. It is an expanded view which shows the tread pattern concerning another embodiment of this invention.

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

  FIG. 1 is a development view showing a tread pattern according to an embodiment of the present invention, in which a pneumatic tire (hereinafter also simply referred to as a tire) is mounted on an applied rim, filled with a specified internal pressure, and brought into an unloaded state. It is a figure which expands and shows the tread surface in the case.

  As shown in FIG. 1, this tire has a plurality of (three in the illustrated example) circumferential main grooves 2 on a tread surface 1. In the illustrated example, the tire includes a tread tread surface 1 and a circumferential main groove 2a that extends on the tire equatorial plane CL, and a circumferential main groove 2b that is disposed symmetrically on each side of the tread width direction. Have. A plurality of (four in the illustrated example) land portions 3a and 3b are partitioned by the three circumferential main grooves 2 and the tread end TE. That is, the tire includes two central land portions 3a adjacent to the outer side in the tread width direction of the circumferential main groove 2a disposed on the tire equatorial plane CL, and two outer land portions 3b adjacent to the tread end TE. Have.

As shown in FIG. 1, the tire has a plurality of inclined grooves 4 extending in the tread width direction in the central land portion 3a. The inclined groove 4 is formed by communicating a first groove 4a with a second groove 4b, which is a narrow groove having a groove width smaller than the groove width of the first groove 4a. The inclined groove 4 is a circumferential main groove. It extends inward in the tread width direction from 2b and terminates in the central land portion 3a. That is, the first groove 4a communicates with the circumferential main groove 2a, and the second groove 4b terminates in the central land portion 3a.
Hereinafter, the effect of this embodiment is demonstrated.

According to the tire of the present embodiment, first, since the inclined groove 4 terminates in the land portion 3a, the rigidity of the central land portion 3a can be ensured. Since the central land portion 3a is a land portion located in the center portion of the ground contact, the responsiveness at the initial stage of steering can be improved, and the steering stability can be improved. Further, the inclined groove 4 includes a first groove 4a and a second groove 4b, and the first groove 4a having a large groove width communicates with the circumferential main groove 2a. However, the rigidity of the land portion 3a can be ensured by the small width of the second groove 4b.
Therefore, according to the tire of this embodiment, it is possible to achieve both drainage and responsiveness at the initial stage of steering.

Further, as shown in FIG. 1, in the present invention, a circumferential sipe 5 extending in the tread circumferential direction at the end of the second groove 4b opposite to the side communicating with the first groove 4a. It is preferable to have width direction sipes 6 and 7 extending in the tread width direction at both ends of the circumferential sipe 5. In the illustrated example, the inclined grooves 4 and the width direction sipes 6 are alternately arranged in the tread circumferential direction. Further, the inclined grooves 4 and the width direction sipes 7 are alternately arranged in the tread circumferential direction. Further, in the illustrated example, one end of the inclined groove 4 on the inner side in the tread width direction communicates with the circumferential sipe 5.
This is because by shifting the positions of the inclined grooves 4 and the width-direction sipes 6 and 7 in the tread circumferential direction, the land portion can be prevented from falling in the front-rear direction and the braking performance can be improved.

Moreover, as shown in FIG. 1, the width direction sipes 6 and 7 communicate with the circumferential main grooves 2b and 2a, respectively, and the width direction sipes 6 and 7 are inclined and extend with respect to the tread width direction. Is preferred. In the illustrated example, the width direction sipes 6 and 7 located in one half of the tread width direction centered on the tire equatorial plane CL are both on the same side (one side in the tread circumferential direction from the inner side to the outer side in the tread width direction). (However, when viewed from the communication portion with the circumferential sipe 5 as a starting point, the width-direction sipes 6 and 7 extend to opposite sides in the tread width direction.) On the other hand, both of the width direction sipes 6 and 7 located in the other half of the tread width direction centered on the tire equatorial plane CL are the same side in the tread circumferential direction from the inner side to the outer side in the tread width direction (the other side). ) Incline and extend.
This is because the drainage can be further improved by connecting the terminal portion of the inclined groove 4 to the circumferential main grooves 2a and 2b via the circumferential sipe 5 and the widthwise sipes 6 and 7.
Moreover, because the width direction sipe is inclined with respect to the tread width direction, the turning noise can be reduced and the noise performance can be improved.

  Furthermore, as shown in FIG. 1, it is preferable that the circumferential sipe 5 extends while being inclined with respect to the tread circumferential direction. This is because water is easily discharged from the center of the ground to the outside in the tread width direction, and drainage is further improved.

  In addition, the width direction sipes 7 connected to the circumferential main groove 2a and located in the opposite half of the tread width direction with the tire equatorial plane CL as a boundary may be provided shifted in the tread circumferential direction. preferable. This is because pattern noise can be reduced.

  Here, in the present invention, the number of the circumferential main grooves 2 is preferably 3 or more. Furthermore, in the example shown in FIG. 1, the circumferential main groove 2 is linear, but it may be zigzag or curved.

Further, for the inclined groove 4, the groove width of the first groove 4 a is preferably 3 to 7 mm in consideration of the balance between drainage and land rigidity, and the groove depth is 4 to 8 mm. It is preferable to do. The groove width of the second groove 4b is preferably 2 to 4 mm in consideration of the balance between drainage and land rigidity, and the groove depth is preferably 3 to 6 mm.
It is preferable to make the groove depth of the first groove 4a deeper than the groove depth of the second groove 4b from the viewpoint of achieving both rigidity and drainage.
Furthermore, the inclination angle of the inclined groove 4 with respect to the tread width direction is preferably 5 to 40 °. This is because the noise performance can be secured by setting it to 5 ° or more, while the drainage performance can be secured by setting it to 40 ° or less. The “inclination angle” means an inclination angle of a line segment connecting both ends of the groove center line (line connecting the midpoints of the groove width), and the same applies to other inclination angles.
As shown in the figure, the connecting portion between the first groove 4a and the second groove 4b has a curved portion in plan view. That is, in the illustrated example, one groove wall of the first groove 4a is formed so as to extend the groove wall of the second groove 4b, and the other groove wall of the first groove 4a is the first groove wall. The groove width of the groove 4a is increased to form a corner, which is curved.

  Next, it is preferable that the circumferential sipe 5 is inclined at an angle of 5 ° to 15 ° with respect to the tread circumferential direction. By tilting at an angle of 5 ° or more, water becomes easy to be discharged from the center of the ground to the outside in the tread width direction. On the other hand, by tilting at an angle of 15 ° or less, longitudinal rigidity This is because the braking performance can be improved.

  Moreover, it is preferable that the width direction sipes 6 and 7 are inclined and extended at an angle of 10 ° to 50 ° with respect to the tread width direction. By setting the angle to 10 ° or more, it is possible to reduce the turning sound and improve the noise performance. On the other hand, by setting it to 50 ° or less, the edge pressure by the width direction sipes 6 and 7 is increased, This is because the effect of removing can be enhanced and the drainage can be improved.

Next, the outer land portion 3b will be described.
First, a plurality of lateral grooves 8 extending inward in the tread width direction from the tread end TE are arranged in the outer land portion 3b. In order to suppress heel and toe wear, the lateral groove 8 is terminated in the outer land portion 3b without communicating with the circumferential main groove 2b.
In addition, one width direction sipe 9 is disposed between the horizontal grooves 8. Since the width-direction sipe 9 communicates with the circumferential main groove 2b and the tread end TE, drainage can be improved. On the other hand, by disposing the width direction sipe 9 instead of the lateral groove 8, the rigidity of the land portion can be secured and the steering stability and the like can be secured.

  Moreover, the width direction sipe 10 that extends inward in the tread width direction from the width direction inner side end portion of the lateral groove 8 and terminates in the outer land portion 3b is disposed in the outer land portion 3b. In the illustrated example, the width-direction sipe 10 is terminated in the outer land portion 3b in order to ensure the rigidity of the outer land portion 3b. However, in order to improve drainage, the circumferential main groove 2b You may communicate with.

  Further, a circumferential sipe 11 extending in the tread circumferential direction is disposed at the inner end of the width sipe 10 in the tread width direction. By this circumferential sipe 11, the compression rigidity of the said part can be reduced moderately and riding comfort can be improved. The rigidity can be adjusted by the extending length of the circumferential sipe 11. Alternatively, in the present invention, the width direction sipe 10 and the circumferential direction sipe 11 may not be provided.

  Here, considering the balance between drainage and land rigidity, the width of the lateral groove 8 is preferably 3 to 7 mm, and the groove depth is preferably 3 to 7 mm. Moreover, it is preferable that the horizontal groove 8 inclines at an angle of 30 degrees or less with respect to the tread width direction from a viewpoint of ensuring drainage.

The groove width of the width direction sipe 9 is preferably 0.5 to 1.4 mm, and the sipe depth is preferably 2 to 6 mm. And it is preferable that the width direction sipe 9 inclines at an angle of 30 degrees or less with respect to the tread width direction from a viewpoint of ensuring drainage.
Furthermore, the groove width of the width-direction sipe 10 is preferably 0.5 to 1.4 mm, and the sipe depth is preferably 2 to 6 mm.
The groove width of the circumferential sipe 11 is preferably 0.3 to 1.1 mm, and the sipe depth is preferably 2 to 6 mm.

Next, FIG. 2 is a development view showing a tread pattern according to another embodiment of the present invention, in which the tread surface is developed when a tire is mounted on an applied rim, filled with a specified internal pressure, and brought into a no-load state. It is a figure shown.
The tire shown in FIG. 2 first has four circumferential grooves 2 on the tread surface 1, and five land portions 3c, 3d, and 3e are defined by the circumferential grooves 2 and the tread ends TE. This is different from the tire shown in FIG.
Specifically, as shown in FIG. 2, one central land portion 3 c is defined between two circumferential grooves 2 a that are disposed at positions closest to the tire equatorial plane CL. The central land portion 3c is located on the tire equatorial plane CL in the illustrated example. In addition, two intermediate grooves 2a, which are disposed closest to the tire equatorial plane CL, and two circumferential grooves 2b adjacent to the outer side of the circumferential groove 2a in the tread width direction, are provided. Part 3d is partitioned. The two outer land portions 3e are partitioned by the circumferential groove 2b and the tread end TE.

As shown in FIG. 2, the central land portion 3 c has a plurality of central inclined grooves 12 that have one end communicating with the circumferential groove 2 a and the other end staying in the central land portion 3 c without straddling the tire equator plane CL. Is formed. These central inclined grooves 12 are alternately formed between the tread width direction halves centered on the tire equatorial plane CL, and each of the tread width direction halves from the outer side to the inner side of the tread width direction. Inclined and extend in the opposite direction. In addition, the central land portion 3c has one end communicating with the central inclined groove 12 and the other end communicating with the circumferential groove 2a in the half of the tread width direction opposite to the central inclined groove 12. A sipe 13 in the width direction is provided. In the illustrated example, when the communication portion between the central width direction sipe 13 and the central inclined groove 12 is viewed as a starting point, the central width direction sipe 13 and the central inclined groove 12 extend in the same direction in the tread circumferential direction and have a tread width. Extending in opposite directions.
The circumferential groove 2a, the central inclined groove 12, and the central width direction sipe 13 define a substantially parallelogram land portion in the illustrated example.

Here, as shown in FIG. 2, the central inclined groove 12 has an extension length in the tread width direction of 50% or less of the width in the tread width direction of the central land portion 3c, and the central land portion 3c has a rib-like shape. It is formed as a land part. Therefore, the rigidity of the central land portion is high, and steering stability can be ensured.
In consideration of the balance between drainage and land rigidity, the groove width of the central inclined groove 12 is preferably 2 to 5 mm, and the inclination angle of the central inclined groove 12 with respect to the tread width direction is It is preferable to set it as 5-50 degrees.
Further, the groove width of the central width direction sipe 13 is preferably 0.5 to 1.0 mm, and the sipe depth is preferably 1.5 to 6 mm. And it is preferable that the center width direction sipe 13 inclines at an angle of 40 degrees or less with respect to the tread width direction. In addition, it is preferable to arrange | position the center width direction sipe 13 from the viewpoint of reducing pattern noise, shifting | deviating the position of the tread circumferential direction with respect to another groove | channel or sipe.

  In addition, from the viewpoint of improving the rigidity of the land portion, the central land portion 3c may be configured without a groove or a sipe.

  Next, the intermediate land portion 3d of the embodiment shown in FIG. 2 has the same configuration as the central land portion 3a of the embodiment shown in FIG. Therefore, the same effect as the tire shown in FIG. 1 can be obtained.

  Further, the outer land portion 3e of the embodiment shown in FIG. 2 has the same configuration as the outer land portion 3b of the embodiment shown in FIG. Therefore, the same effect as the tire shown in FIG. 1 can be obtained.

Since the tire of the embodiment shown in FIG. 1 has a pattern having three circumferential main grooves 2, the rigidity of the land portion 3 partitioned by these circumferential main grooves 2 can be ensured. Accordingly, although not particularly limited, in the case of a tire having a tire having a cross-sectional width of 195 mm or less, the steering stability can be ensured particularly during cornering or lane change by using the pattern shown in FIG. . Moreover, if the tire has such a cross-sectional width, the drainage can be sufficiently secured even with the three main grooves.
On the other hand, since the tire according to the embodiment shown in FIG. 2 has a pattern having four circumferential main grooves 2, sufficient drainage can be secured even in a tire having a large tire cross-sectional width. In the pattern shown in FIG. 2, the land portion is divided into five sections. However, in the case of a tire having a large tire cross-sectional width, sufficient rigidity of the land portion is ensured, and steering stability during cornering or lane change is ensured. Can be secured. Therefore, although not particularly limited, the pattern shown in FIG. 2 is preferably applied to a tire having a tire whose cross-sectional width is 225 mm or more.

FIG. 3 is a development view showing a tread pattern according to another embodiment of the present invention. The tire shown in FIG. 3 has a circumferential sipe 5 extending in the tread circumferential direction at the end of the second groove 4b opposite to the side communicating with the first groove 4a. 5 has a width-direction sipe 7 extending in the tread width direction at one end in the tread circumferential direction, and a width-direction narrow groove 14 extending in the tread width direction at the other end in the tread circumferential direction of the circumferential sipe 7. This is different from the tire of the embodiment shown in FIG.
Here, the width direction narrow groove 14 includes a sipe portion 14a communicating with the circumferential sipe 5 and a chamfered portion 14b chamfered so that the depth increases toward the sipe portion 14a. In this embodiment, the chamfered portion 14b has a tapered shape. However, the chamfered portion 14b may have a curved shape so as to have a center of curvature inside or outside the tire.
In addition, it is preferable that the groove width of the width direction fine groove 14 shall be 2-4 mm from a viewpoint of improvement in grounding property.
In the tire of the embodiment shown in FIG. 3, the outer land portion 3b is provided with a widthwise narrow groove 15 that extends inward in the tread width direction from the widthwise inner end of the lateral groove 8 and terminates in the outer land portion 3b. This is also different from the tire of the embodiment shown in FIG. In the illustrated example, the width-direction narrow groove 15 is terminated in the outer land portion 3b in order to ensure the rigidity of the outer land portion 3b, but in order to improve drainage, the circumferential main groove You may make it communicate with 2b.
Here, the width direction narrow groove 15 includes a sipe portion 15a communicating with the circumferential sipe 11, and a chamfered portion 15b chamfered so that the depth increases toward the sipe portion 15a. In the present embodiment, the chamfered portion 15b has a tapered shape, but may have a curved shape so as to have a center of curvature inside or outside the tire.
In addition, it is preferable from the viewpoint of improving the grounding property that the groove width of the width direction narrow groove 15 is 30 to 50% of the groove width of the lateral groove 8.
In the embodiment shown in FIGS. 1 and 2, the second groove 4 b is a narrow groove, whereas in the embodiment shown in FIG. 3, the second groove 4 b is the first groove in the plan view. The sipe portion 4b1 has a shape that forms a straight line with the side wall on one side of the groove 4a, and a chamfered portion 4b2 that is chamfered so that the depth increases toward the sipe portion 4b1. In the present embodiment, the chamfered portion 4b2 has a tapered shape, but may have a curved shape so as to have a center of curvature inside or outside the tire.

  Further, in the illustrated example, a circumferential sipe 11 extending in the tread circumferential direction is disposed at the inner end of the width direction narrow groove 15 in the tread width direction. By this circumferential sipe 11, the compression rigidity of the said part can be reduced moderately and riding comfort can be improved. The rigidity can be adjusted by the extending length of the circumferential sipe 11.

According to the tire of the embodiment shown in FIG. 3, first, the basic configuration is the same as that of the tire of the embodiment shown in FIG. Can be played.
Further, in the tire of the embodiment shown in FIG. 3, the central land portion 3 a has the width direction narrow groove 14 extending in the tread width direction at the end of the circumferential direction sipe 7 on the other side in the tread direction. Compared with the tire of the embodiment shown in FIG. 1, the drainage is further improved. Further, also in the side land portion 3b, the width direction narrow groove 15 extending from the width direction inner side end portion of the lateral groove 8 to the inner side in the tread width direction and terminating in the outer land portion 3b is disposed, and therefore, shown in FIG. Compared with the tire of the embodiment, the drainage is further improved.

Further, as shown in FIG. 3, it is preferable that the end of the width direction narrow groove 14 on the side communicating with the circumferential sipe 5 has a narrower groove width than the other part of the width direction narrow groove 14. This is because concentration of distortion can be prevented.
Furthermore, in the embodiment shown in FIG. 3, the groove width of the width direction narrow groove 14 is preferably larger than the groove width of the second groove. This is because the drainage can be further secured.

In order to confirm the effect of the present invention, the tires according to Invention Examples 1 to 5 and the tires according to Comparative Examples 1 and 2 were experimentally manufactured, and a test for evaluating the performance of the tire was performed.
The specifications of each tire are shown in Table 1 below.
In Table 1, “inclination angle of the width direction sipes 6 and 7” refers to an inclination angle with respect to the tread width direction, and “inclination angle of the circumferential direction sipe 5” refers to an inclination angle with respect to the tread circumferential direction. Further, “with displacement” means that the width direction sipe 7 is not on the extension line of the inclined groove 4 and is displaced in the tread circumferential direction.
Inventive Examples 1 to 4 and Comparative Example 1 are tires having a pattern having three circumferential grooves 2, while Inventive Example 5 and Comparative Example 2 are tires having a pattern having four circumferential grooves 2. It is.

Each of the above tires having a tire size of 195 / 65R15 was incorporated into an applicable rim, filled with a specified internal pressure, and the following tests were performed.
<Drainage>
Drainability was evaluated by accelerating a wet road surface with a depth of 7 mm and comparing the rate of occurrence of the hydroplaning phenomenon.
Evaluation is index evaluation with a relative value when the evaluation result of the tire according to Comparative Example 1 is set to 100, and a larger numerical value indicates better drainage.
<Response at the beginning of steering>
Sensory evaluation by a driver was performed. The evaluation is an index evaluation with a relative value when the evaluation result of the tire according to Comparative Example 1 is set to 100, and the larger the value, the better the response at the initial stage of steering.
<Noise performance>
Sensory evaluation by a driver was performed. Evaluation is index evaluation with a relative value when the evaluation result of the tire according to Comparative Example 1 is set to 100, and a larger numerical value indicates better noise performance.
<Brake performance>
The vehicle was suddenly braked from an initial speed of 20 km / hour. And the braking distance until a vehicle became a stationary state was measured, and braking performance was evaluated from this braking distance. Evaluation is index evaluation with a relative value when the evaluation result of the tire according to Comparative Example 1 is set to 100, and a larger numerical value indicates better braking performance.
These evaluation results are shown in Table 1 below together with tire specifications.

  As shown in Table 1, it can be seen that the tires according to the inventive examples 1 to 4 are both compatible with the drainage and the initial steering response as compared with the tire according to the comparative example 1. . Further, by comparing the invention example 1 and the invention example 2, the invention example 1 having the circumferential sipe 5 and having the width direction sipe 7 not on the extension line of the inclined groove 4 and shifted in the tread circumferential direction is the invention example. 2 shows that the braking performance is superior. Further, in comparison between Invention Example 1 and Invention Example 3, the width direction sipes 6, 7 communicate with the circumferential main groove 2, and the width direction sipes 6, 7 are inclined with respect to the tread width direction. From the invention example 3, it turns out that it is excellent by drainage property and noise performance. And by comparison between Invention Example 1 and Invention Example 4, it can be seen that Invention Example 1 in which the circumferential sipe 5 is inclined with respect to the tread circumferential direction is superior to the Invention Example 4 in drainage. Further, it can be seen that the tire according to Invention Example 5 can achieve both drainage and responsiveness at the initial stage of steering as compared with the tire according to Comparative Example 2.

  Next, regarding tires having a tire size of 235 / 40R17, tires according to Invention Examples 6 to 8 and Comparative Example 3 were prototyped and evaluated in the same manner as described above. Table 2 below shows the specifications and evaluation results of each tire. In Table 2, for each evaluation item, index evaluation is performed with a relative value when the evaluation result according to Comparative Example 3 is set to 100, and a larger value indicates better performance.

  As shown in Table 2, it can be seen that the tires according to Invention Examples 6 to 8 are both compatible with the drainage and the initial steering response as compared with the tire according to Comparative Example 3. . Further, according to a comparison between Invention Example 1 and Invention Example 2, Invention Example 6 having a circumferential sipe 5 and having a width-direction sipe 7 not on the extension line of the inclined groove 4 is shifted in the tread circumferential direction. 7 shows that the braking performance is excellent. Further, in comparison between Invention Example 6 and Invention Example 8, the width direction sipes 6, 7 communicate with the circumferential main groove 2, and the width direction sipes 6, 7 are inclined with respect to the tread width direction. From the invention example 8, it turns out that it is excellent by drainage property and noise performance.

  Next, a tire according to Invention Example 9 having a tread pattern shown in FIG. The evaluation method is the same as described above. The evaluation results are shown in Table 3 below.

  As shown in Table 3, it can be seen that the tire according to Invention Example 9 is more excellent in drainage than the tire according to Invention Example 1.

1 tread tread 2, 2a, 2b circumferential main groove 3 land portion 3a central land portion 3b outer land portion 3c central land portion 3d intermediate land portion 3e outer land portion 4 inclined groove 4a first groove 4b second groove 5 turn Direction sipe 6 width direction sipe 7 width direction sipe 8 transverse groove 9 width direction sipe 10 width direction sipe 11 circumferential direction sipe 12 central inclined groove 13 central width direction sipe 14 width direction narrow groove 15 width direction narrow groove

Claims (4)

The tread tread has a plurality of circumferential main grooves, and a plurality of land portions are defined by the plurality of circumferential main grooves and tread ends,
A plurality of inclined grooves extending incline in the tread width direction on two land portions adjacent to the outer side in the tread width direction of the circumferential main groove arranged at a position closest to the tire equator plane;
The inclined groove is formed by communicating a first groove and a second groove having a groove width smaller than the groove width of the first groove.
The first groove communicates with the circumferential main groove disposed at a position closest to the tire equatorial plane ,
The inclined groove terminates in the land portion ,
A circumferential sipe extending in the tread circumferential direction at the end of the second groove opposite to the side communicating with the first groove;
Wherein each of the opposite ends of the circumferential sipe, characterized in that that have a widthwise sipes extending in the tread width direction, the pneumatic tire. The width sipe communicates with the circumferential main groove,
The pneumatic tire according to claim 1 , wherein the width-direction sipe extends while being inclined with respect to the tread width direction. The circumferential sipe extends obliquely with respect to the tread circumferential direction, the pneumatic tire according to claim 1 or 2. The tread tread has a plurality of circumferential main grooves, and a plurality of land portions are defined by the plurality of circumferential main grooves and tread ends,
A plurality of inclined grooves extending incline in the tread width direction on two land portions adjacent to the outer side in the tread width direction of the circumferential main groove arranged at a position closest to the tire equator plane;
The inclined groove is formed by communicating a first groove and a second groove having a groove width smaller than the groove width of the first groove.
The first groove communicates with the circumferential main groove disposed at a position closest to the tire equatorial plane,
The inclined groove terminates in the land portion ,
A circumferential sipe extending in the tread circumferential direction at the end of the second groove opposite to the side communicating with the first groove;
The circumferential sipe has a widthwise shape that extends in the tread width direction at one end in the tread circumferential direction, and a width that extends in the tread width direction at the other end in the tread circumferential direction of the circumferential sipe. It characterized in that it has a narrow groove, the pneumatic tire.

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