JP6571993B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire.

  Conventionally, a pattern having a circumferential main groove extending continuously in a zigzag shape in the tire circumferential direction is known as a tread pattern that achieves both tire drainage performance and off-road running performance (for example, Patent Document 1). reference). According to such a tread pattern, the traction performance can be ensured by the edge effect by the width direction component while enhancing the drainage by the tire circumferential direction component of the circumferential main groove. In the tire having a tread pattern as described in Patent Document 1, the ratio of the component in the tire width direction of the circumferential main groove in order to ensure traction performance on rough roads such as muddy ground, gravel road, snowy road, etc. There are tires that are larger.

JP 2011-235853 A

  As in Patent Document 1, in a tire in which the ratio of the component in the tire width direction of the circumferential main groove is increased, the outside noise tends to increase. In recent years, there has been an increasing demand to reduce the passage noise during vehicle running in urban areas, etc., and even tires with high drainage performance and traction performance on bad roads such as muddy areas, gravel roads, snowy roads, etc. There is a demand for a technique that can improve the quietness.

  The present invention is intended to solve the above problem, and provides a pneumatic tire that can improve wear resistance and quietness while maintaining high drainage performance and traction performance. The purpose is to do.

The gist configuration of the present invention is as follows.
The pneumatic tire of the present invention has at least one land portion sandwiched between a plurality of circumferential main grooves extending in the tire circumferential direction on the tread surface, and the land portion includes the plurality of circumferential portions sandwiching the land portion. A plurality of blocks are formed in the directional main groove that are partitioned by lateral grooves that are open at both ends, the block having one end opening in the circumferential main groove, the other end terminating in the block, and In a developed view of the tread surface, an inclined groove extending obliquely with respect to the tire circumferential direction is formed, and the inclined groove is connected to the circumferential main groove and to the connecting portion. A wide portion and a narrow portion connected to the wide portion, and in a developed view of the tread surface, the wide portion and the narrow portion have a smaller inclination angle with respect to a tire circumferential direction than the connecting portion, and the block Has one end open to the connecting part And the other end has an opening sipe is formed in the circumferential main grooves, the development view of the tread surface, the sipe has a bent portion, characterized in that those.
According to the pneumatic tire of the present invention, it is possible to improve wear resistance and quietness while maintaining high drainage performance and traction performance.

  Here, the `` tread surface '' means that when a tire that is assembled to the applicable rim and filled with the specified internal pressure is rolled with a load corresponding to the maximum load capacity applied, the tire will come into contact with the road surface. It means the outer peripheral surface over the entire circumference of the tire. Here, the “applicable rim” is a standard rim defined in the following standard according to the tire size (“Design Rim” in YEAR BOOK of TRA below. “Measuring Rim” in STANDARDDS MANUAL of ETRTO below). The "specified internal pressure" means the air pressure specified in accordance with the maximum load capacity in the following standards, and the "maximum load capacity" is allowed to be applied to the tire according to the following standards. The maximum mass. The standard is determined by an industrial standard that is effective in the region where the tire is produced or used. For example, in the United States, “YEAR BOOK” of “The Tire and Rim Association, Inc. (TRA)” is used. “In Europe,“ The European Tire and Rim Technical Organization (ETRTO) ”is“ STANDARDS MANUAL ”. In Japan,“ Japan Auto Tire Association (JATMA) ”is“ JATMA YEAR BOOK ”.

  Further, the phrase “the circumferential main groove extends in the tire circumferential direction” means that the circumferential main groove extends in the tire circumferential direction, and the circumferential main groove extends in a zigzag shape toward the tire circumferential direction or is curved in the tire circumferential direction. The case of extending is also included.

In the pneumatic tire of the present invention, it is preferable that the groove width of the wide width portion becomes narrower toward the narrow width portion when the tread surface is developed.
According to this configuration, the wear resistance can be further improved by increasing the block rigidity while maintaining high drainage performance.

In the pneumatic tire of the present invention, the block has a chamfered portion on a side wall extending in the extending direction of the other end side of the inclined groove, and the inclined groove is in a developed view of the tread surface. Preferably, the tire circumferential direction dimension of the inclined groove and the chamfered portion extends to a position that is 200% or less of the maximum dimension of the block in the tire circumferential direction.
According to this configuration, the wear resistance can be further improved by increasing the block rigidity while maintaining high drainage performance.

In the pneumatic tire of the present invention, it is preferable that the block is divided into a first block portion and a second block portion by the connecting portion and the sipe.
According to this configuration, the wear resistance can be further improved by increasing the block rigidity.

In the pneumatic tire of the present invention, the outer side wall in the tire width direction of the first block portion is located on the outer side in the tire width direction than the outer side wall in the tire width direction of the second block portion. It is preferable.
According to this configuration, the traction performance can be further improved.

In the pneumatic tire of the present invention, the first block portion preferably has a tire circumferential dimension that decreases toward the outer side in the tire width direction.
According to this structure, handling performance can be improved and steering stability can be improved.

In the pneumatic tire of the present invention, it is preferable that a convex portion is formed on one of the side walls of the second block portion defined by the circumferential main groove in a development view of the tread surface.
According to this configuration, the traction performance can be further improved.

In the pneumatic tire of the present invention, it is preferable that a concave portion is formed on one of the side walls of the second block portion defined by the circumferential main groove in a developed view of the tread surface.
According to this configuration, the traction performance can be further improved.

In the pneumatic tire of the present invention, at least one of the circumferential main grooves is composed of a plurality of circumferentially divided main grooves divided in the tire circumferential direction, and is divided into two circumferentially divided tires adjacent to the tire circumferential direction. A connecting groove for connecting the two circumferentially divided main grooves is disposed between the main grooves, and the connecting groove is divided in the circumferential direction of the first block portion in a developed view of the tread surface. It is preferable that the tire is disposed adjacent to the side wall defined by the main groove in the tire circumferential direction.
According to this configuration, quietness can be further improved while maintaining high drainage performance and traction performance.

  According to the present invention, it is possible to provide a pneumatic tire that can improve wear resistance and quietness while maintaining high drainage performance and traction performance.

It is an expanded view which shows the tread pattern of the pneumatic tire concerning one Embodiment of this invention. It is a figure which shows typically the cross section of the tire width direction of the groove bottom of the connection groove | channel of FIG.

  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 of a pneumatic tire (hereinafter also simply referred to as a tire) according to an embodiment of the present invention. The tire is mounted on an applied rim, filled with a specified internal pressure, FIG. 2 is a diagram schematically showing a cross section in the tire width direction of a groove bottom of a connecting groove in FIG. 1 to be described later. Hereinafter, unless otherwise specified, the shape and dimensions of the tread pattern are those in the above state or when the tread tread is viewed in the developed state.

As shown in FIG. 1, in a tire according to an embodiment of the present invention, a tread surface 1 is formed with a circumferential main groove extending in the tire circumferential direction. In the example of FIG. 1, it has three circumferential main grooves 21, 22, and 23, and the outermost circumferential main groove 21 on one side in the tire width direction and the outermost outer groove on the other side in the tire width direction. The circumferential main groove 22 is formed to extend linearly along the tire circumferential direction. In the present embodiment, a circumferential main groove 23 is formed in the vicinity of the tire equatorial plane CL. The circumferential main groove 23 of the present embodiment is composed of a plurality of circumferentially divided main grooves 24 divided in the tire circumferential direction.
In the present embodiment, these circumferential main grooves 21, 22 and 23 can ensure the drainage of the tire.
In the embodiment shown in FIG. 1, the outermost circumferential main grooves 21 and 22 are formed so as to be point-symmetric about one point on the tire equatorial plane CL.

  The circumferentially divided main groove 24 of the present embodiment is formed so that the position in the tire width direction of the one side end 24a in the tire circumferential direction is different from the position in the tire width direction of the other side end 24b in the tire circumferential direction. . Here, “the position in the tire width direction at one end in the tire circumferential direction and the position in the tire width direction at the other end in the tire circumferential direction are different” means that the one end and the other end are in the tire width direction. It has a part which does not overlap each other. As shown in FIG. 1, in the present embodiment, a circumferentially divided main groove 24 is formed so that one side end 24 a and the other side end 24 b partially overlap in the tire width direction. Thus, by forming the circumferentially divided main groove 24 so that the position in the tire width direction of the one side end 24a in the tire circumferential direction is different from the position in the tire width direction of the other side end 24b in the tire circumferential direction, The traction performance obtained by the circumferentially divided main groove 24 is enhanced.

The circumferentially divided main groove 24 of the present embodiment is connected to a first circumferential portion 24c extending in the tire circumferential direction along the tire circumferential direction from one side end 24a in the tire circumferential direction, and to the first circumferential portion 24c. An inclined portion 24d extending obliquely with respect to the tire circumferential direction, and a second circumferential portion connected to the inclined portion 24d and extending in the tire circumferential direction along the tire circumferential direction to the other end 24b in the tire circumferential direction. 24e. In the present embodiment, the groove wall of the inclined portion 24d is chamfered and inclined. Therefore, the block rigidity of the block 7 can be increased and the wear resistance can be increased.
Here, the first circumferential portion and the second circumferential portion “extend in the tire circumferential direction along the tire circumferential direction” not only when extending in parallel with the tire circumferential direction but also with respect to the tire circumferential direction. And tilting in the range of 5 ° to 20 °. In addition, the inclined portion "inclined with respect to the tire circumferential direction and extends in the tire circumferential direction" means that the inclined portion extends with an inclination with respect to the tire circumferential direction rather than the first circumferential direction portion and the second circumferential direction portion. Means that.
In the present embodiment shown in FIG. 1, the first circumferential portion 24c and the second circumferential portion 24e each extend in parallel to the tire circumferential direction. Further, the inclined portion 24d extends with an inclination of 25 ° with respect to the tire circumferential direction.
By configuring the circumferentially divided main groove 24 to include the circumferential portions 24c and 24e and the inclined portion 24d, the circumferential portions 24c and 24e improve drainage, and from the circumferential portions 24c and 24e. The traction performance can be further improved by obtaining a large shear force in the snow at the inclined portion 24d having a large inclination angle with respect to the tire circumferential direction.

  In the present embodiment, between the two circumferentially divided main grooves 24 adjacent to each other in the tire circumferential direction, one end 24a of the circumferentially divided main groove 24, and the other adjacent to the circumferentially divided main groove 24 in the tire circumferential direction. A connecting groove 25 that connects the other end 24b of the circumferentially divided main groove 24 is disposed. By connecting the two circumferentially divided main grooves 24 adjacent to each other by the connecting groove 25, the drainage performance and the traction performance are enhanced. As shown in FIG. 2, the connecting groove 25 is formed in a curved shape in which the cross-sectional shape of the groove bottom 25 a along the tire width direction of the connecting groove 25 is concave toward the center of the connecting groove 25 in the tire width direction. Yes. Moreover, the traction performance is further improved by making the cross-sectional shape of the groove bottom 25a along the tire width direction of the connecting groove 25 into a curved surface.

In the present embodiment shown in FIG. 1, as described above, the circumferentially divided main groove 24 is formed so that the one side end 24a and the other side end 24b partially overlap in the tire width direction. Therefore, in the tread pattern of the present embodiment, a flow path extending in the tire circumferential direction is secured by the connecting groove 25 between two adjacent circumferentially divided main grooves 24, and sufficient drainage can be secured. . From the viewpoint of ensuring drainage, the other side end 24b of the other circumferentially divided main groove 24 adjacent to the one side end 24a of the circumferentially divided main groove 24 is the one side end 24a and the other side end 24a in the tire width direction. The one side end 24a and the other side end 24b may not overlap in the tire width direction as long as they are not separated from the dimension in the tire width direction of the circumferentially divided main groove 24 at the other side end 24b.
The positions of the one side end 24a and the other side end 24b of the circumferentially divided main groove 24 are changed in the tire width direction, the two adjacent circumferentially divided main grooves 24 are connected by the connecting groove 25, and the tire width direction of the connecting groove 25 is determined. Since the cross-sectional shape of the groove bottom 25a along the surface is curved, the ratio of the tire width direction component of the groove in the entire tread surface is reduced while maintaining high traction performance, and quietness can be improved.

As shown in FIG. 1, in this embodiment, a plurality of land portions are defined by three circumferential main grooves 21, 22, and 23 and tread tread ends TE1 and TE2. Specifically, an outer land portion 31 on one side in the tire width direction is defined by the circumferential main groove 21 and the tread tread surface end TE1 on one side in the tire width direction, and the circumferential main groove 21 and the circumferential main groove are formed. 23, the intermediate land portion 32 on one side in the tire width direction is partitioned and formed, and the intermediate land portion 33 on the other side in the tire width direction is partitioned and formed by the circumferential main groove 23 and the circumferential main groove 22 in the circumferential direction. An outer land portion 34 on the other side in the tire width direction is defined by the main groove 22 and the tread tread end TE2 on the other side.
In the example of illustration, it forms so that the dimension of the tire width direction of the outer side land part 31 and the outer side land part 34 may become equal. Further, the intermediate land portion 32 and the intermediate land portion 33 are formed to have the same size in the tire width direction.

The outer land portion 31 of the present embodiment is formed with a lug groove 41 having one end opened to the tread tread surface end TE1 and the other end opened to the circumferential main groove 21. In the present embodiment, the outer land portion 31 is further formed with a recess 61 that is recessed outward in the tire width direction on the side wall defined by the circumferential main groove 21. By providing the recessed part 61, the shear force in snow obtained becomes large and it can improve a traction performance. The bottoms of some of the recesses 61 are configured in steps so that the dimensions in the tire radial direction increase toward the circumferential main groove 21. By making the bottom stepped, the edge component increases and the traction performance can be further improved. Note that the bottoms of all the recesses 61 may be stepped, and the bottoms of all the recesses 61 may not be stepped.
The outer land portion 31 of the present embodiment is also formed with a plurality of sipes 51 having one end opened to the tread tread end TE1 and the other end opened to the circumferential main groove 21. In the present embodiment, the sipe 51 has a bending point. In the present embodiment, a part of the sipe 51 a formed in the outer land portion 31 opens into the circumferential main groove 21 via the recess 61.
Here, “sipe” refers to a thin notch cut into the inside from the outer surface of the land portion, which can be closed at the time of ground contact.

  In the present embodiment, a lug groove 41, a sipe 51, and a recess 61 are formed in the outer land portion 34 on the other side with the same configuration as the outer land portion 31 on the one side. Specifically, in the outer land portion 34, one end of the lug groove 41 and the sipe 51 is open to the tread tread surface end TE2 and the other end is the circumferential main groove 22 (a part of the sipe 51a is interposed through the recess 61). Opened in the circumferential main groove 22). The recess 61 is formed on the side wall defined by the circumferential main groove 22 of the outer land portion 34 so as to be recessed outward in the tire width direction.

  In the present embodiment, the intermediate land portion 32 sandwiched between the circumferential main grooves 21 and 23 is partitioned by the lateral grooves 42 having both ends opened in the circumferential main grooves 21 and 23 to form a plurality of blocks 7. In the present embodiment, the lateral groove 42 is formed so as to be inclined by 75 ° with respect to the tire circumferential direction. The lateral grooves 42 are preferably inclined at 30 ° to 90 ° with respect to the tire circumferential direction.

  The lateral groove 42 of the present embodiment opens at a connection portion between the first circumferential portion 24c and the inclined portion 24d of the circumferentially divided main groove 24. In other words, one end of the inclined portion 24d in the tire circumferential direction is connected to a lateral groove 42 that opens to the circumferential main groove 24 adjacent to the circumferential main groove 21 in the tire width direction. In the present embodiment, the intermediate land portion 32 is further formed with a recess 62 that is recessed inward in the tire width direction on the side wall defined by the circumferential main groove 21. The lateral groove 42 opens into the circumferential main groove 21 via the recess 62. By providing the recessed part 62, the shear force in the snow obtained becomes large and traction performance can be improved.

  In the block 7 of the present embodiment, an inclined groove 43 that extends in an inclined manner with respect to the tire circumferential direction is formed. The inclined groove 43 of the present embodiment is formed so that one end opens in the circumferential main groove 21 and the other end terminates in the block 7. By providing such an inclined groove 43, drainage performance can be enhanced. In addition, the inclined groove 43 of the present embodiment includes a connecting portion 43a having one end connected to the circumferential main groove, a wide portion 43b having one end connected to the other end of the connecting portion 43a, and the other end of the wide portion 43b. A narrow portion 43c is formed including one end connected and the other end terminating in the block 7.

  In the present embodiment, the wide portion 43b and the narrow portion 43c are such that the extending direction of the wide portion 43b and the narrow portion 43c is inclined with respect to the tire circumferential direction, and the extending direction of the connecting portion 43a is the tire circumferential direction. It forms so that it may become smaller than the angle which inclines with respect to. By setting it as such an angular relationship, the pattern noise by the inclination groove | channel 43 can be reduced and silence performance can be improved. In particular, in the present embodiment, the groove walls on the outer side in the tire width direction of the wide width portion 43b and the narrow width portion 43c are integrally formed with no step. In addition, it is preferable that the angle which the extending direction of the wide part 43b and the narrow part 43c inclines with respect to a tire circumferential direction is 5-45 degrees. Moreover, it is preferable that the angle which the extension direction of the connection part 43a inclines with respect to a tire circumferential direction is 30-90 degrees.

  Moreover, in this embodiment, as shown in FIG. 1, the wide part 43b is formed so that a groove width may become narrow toward the narrow part 43c. When the wide portion 43b is configured in this manner, the block rigidity can be increased and the wear resistance can be increased while maintaining the drainage performance. In the present embodiment, the connecting portion 43a and the narrow width portion 43c are formed so that the groove width is constant. Moreover, in this embodiment, the wide part 43b is formed so that a groove width may become larger than the connection part 43a.

Furthermore, in this embodiment, it is preferable that the wide part 43b is formed so that the dimension of the extending direction of the wide part 43b may be in the range of 25 to 2000% of the dimension of the connecting part 43a in the extending direction. Moreover, it is preferable that the narrow part 43c is formed so that the dimension of the extending direction of the narrow part 43c may be in the range of 5 to 2000% of the dimension of the connecting part 43a in the extending direction.
Here, the dimension in the extending direction of the connecting portion 43a, the wide width portion 43b, and the narrow width portion 43c means the extending direction in the tread surface of the two groove walls of the connecting portion 43a, the wide width portion 43b, and the narrow width portion 43c. The average value of dimensions.

  Furthermore, in this embodiment, the block 7 has a chamfered portion 71 having a chamfered side wall on the extension line in the extending direction on the other end side of the inclined groove 43. More specifically, the chamfered portion 71 is formed by chamfering the side wall on the extension line in the extending direction of the end of the inclined groove 43 that is not connected to the wide width portion 43b of the narrow width portion 43c. In particular, in the present embodiment, the narrow portion 43 c of the inclined groove 43 extends toward the connection portion between the circumferentially divided main groove 24 and the lateral groove 42, and the chamfered portion 71 is the circumferentially divided main groove 24. It is formed in a portion extending from the side wall 72 defined by the inclined portion 24d to the side wall 73 defined by the lateral groove 42. In the present embodiment, by forming the chamfered portion 71, the groove wall of the inclined portion 24d of the circumferentially divided main groove 24 is chamfered and inclined. Therefore, the block rigidity of the block 7 can be increased and the wear resistance can be increased.

  Further, in the present embodiment, the narrow width portion 43c of the inclined groove 43 has a tire circumferential dimension between the narrow width portion 43c of the inclined groove 43 and the chamfered portion 71 in the development view of the tread surface in FIG. 7 extends to a position that is 75% or less of the maximum dimension in the tire circumferential direction. With such a configuration, the drainage performance by the inclined groove can be improved.

In the present embodiment, a plurality of sipes 52 are further formed in the block 7. Of the plurality of sipes 52, the sipe 52 a is formed so that one end thereof opens to the connecting portion 43 a of the inclined groove 43. In the present embodiment, the sipe 52a has a bent portion in a developed view of the tread surface. Therefore, the edge component can be increased to improve the traction performance. Particularly in the present embodiment, the other end of the sipe 52 a is open to the connecting groove 25 that connects the circumferentially divided main groove 24. Therefore, in this embodiment, the block 7 is divided | segmented into the 1st block part 74 and the 2nd block part 75 by the connection part 43a and the sipe 52a. In this embodiment, the drainage performance can be improved by opening the sipe 52a in the connecting groove 25 that connects the circumferentially divided main grooves 24. Further, by dividing the block 7 into the first block portion 74 and the second block portion 75, it is possible to prevent stress from concentrating on a part of the block 7, and to increase the block rigidity and wear resistance. Can be improved.
Further, since the sipe 52a has a bent portion, the connecting portion 43a and the portion divided by the sipe 52a can support each other when deformed to fall down due to the addition of a force such as a side force. Since it can do, it can suppress that a big stress concentrates on one part parted by the connection part 43a and the sipe 52a, and can improve abrasion resistance.

  As shown in FIG. 1, in the present embodiment, the side wall on the outer side in the tire width direction of the first block portion 74 is more than the side wall on the outer side in the tire width direction of the second block portion 75 except for the convex portion 77 described later. Further, it is configured to be located on the outer side in the tire width direction. With such a configuration, there are blocks on the tire circumferential direction line on the side wall on the outer side in the tire width direction of the second block portion 75 and on the tire circumferential direction line on the side wall on the outer side in the tire width direction of the first block portion 74. An area that does not occur is generated, and traction performance can be improved.

  Moreover, in this embodiment, the 1st block part 74 is formed so that the dimension of a tire circumferential direction may become small toward a tire width direction outer side. With such a configuration, the directionality of the obtained edge component is diversified, so that handling performance can be improved and steering stability can be improved.

  In the present embodiment, a convex portion 77 is formed on the side wall 76 of the second block portion 75 that is partitioned by the circumferential main groove 21. By forming the convex part 77, the shear force in snow obtained by forming the area | region where the groove width of the circumferential direction main groove 21 is narrow becomes large, and it can improve a traction performance.

  In the present embodiment, a recess 78 is formed in the side wall 76 of the second block portion 75 that is partitioned by the circumferential main groove 21. By forming the concave portion 78, a shearing force in snow can be obtained in the concave portion 78, so that the traction performance can be improved.

  Furthermore, in this embodiment, the connecting groove 25 is disposed adjacent to the circumferential direction of the side wall of the first block portion 74 that is partitioned by the circumferentially divided main groove 24. By arranging the connecting groove 25 in this way, the obtained shearing force in snow increases, and the traction performance can be improved.

In the present embodiment, a lateral groove 42, an inclined groove 43, a sipe 52, a concave portion 62, a convex portion 77, and a concave portion 78 are formed in the other intermediate land portion 33. Specifically, in the intermediate land portion 33 on the other side, the lateral groove 42 opens in the circumferential main grooves 22 and 23, the inclined groove 43 opens in the circumferential main groove 22, and the sipe 52 a of the plurality of sipes 52 is The circumferential main groove 22 and the connecting groove 25 are opened. Moreover, the recessed part 62, the convex part 77, and the recessed part 78 are formed in the side wall at the side of the circumferential direction main groove 22. As shown in FIG.
Particularly in the present embodiment, the intermediate land portion 33 is formed so as to be point-symmetric with the intermediate land portion 32 around one point on the tire equatorial plane CL.

  Hereinafter, the function and effect of the tire of this embodiment will be described.

  According to the tire of one embodiment of the present invention, first, the intermediate land portions 32 and 33 are partitioned by the lateral grooves 42 having both ends opened in the plurality of circumferential main grooves 21, 22 and 23 sandwiching the intermediate land portions 32 and 33. A plurality of blocks 7 are formed. One end of each block 7 opens into the circumferential main grooves 21 and 22 and the other end terminates in the block 7. An inclined groove 43 that is inclined and extends with respect to the circumferential direction is formed. By providing such an inclined groove 43, drainage performance can be enhanced. The inclined groove 43 includes a connecting portion 43a connected to the circumferential main grooves 21 and 22, a wide width portion 43b connected to the connecting portion 43a, and a narrow width portion 43c connected to the wide width portion 43b. In a developed view, the wide width portion 43b and the narrow width portion 43c are formed so that the inclination angle with respect to the tire circumferential direction is smaller than that of the connection portion 43a. By setting it as such an angular relationship, the pattern noise by the inclination groove | channel 43 can be reduced and silence performance can be improved. Further, the block 7 is formed with a sipe 52a having one end opened to the connecting portion 43a and the other end opened to the circumferential main groove 23. The sipe 52a has a bent portion in a developed view of the tread surface. doing. Therefore, the edge component can be increased to improve the traction performance, and the portions separated by the sipe 52a can support each other when deformed so as to fall down due to the addition of a force such as a side force. Therefore, it is possible to improve wear resistance by suppressing the concentration of a large stress on one portion divided by the sipe 52a. Therefore, it is possible to improve wear resistance and quietness while maintaining high drainage performance and traction performance.

  Here, in the present invention, as shown in one embodiment of FIG. 1, it is preferable that the groove width of the wide width portion 43 b becomes narrower toward the narrow width portion 43 c in the development view of the tread surface. With such a configuration, it is possible to increase block rigidity and maintain wear resistance while maintaining drainage performance.

  Furthermore, in the present invention, as shown in one embodiment of FIG. 1, the block 7 has a chamfered portion 71 on the side wall on the extension line in the extending direction on the other end side of the inclined groove 43. The inclined groove 43 extends to a position where the dimension in the tire circumferential direction between the inclined groove 43 and the chamfered portion 71 is 200% or less of the maximum dimension in the tire circumferential direction of the block 7 in the development view of the tread surface. It is preferable. With such a configuration, since the groove wall of the inclined portion 24d of the circumferentially divided main groove 24 is inclined due to the formation of the chamfered portion 71, the block rigidity of the block 7 is increased and the wear resistance is increased. Can do. Further, since the extending length of the inclined groove 43 can be increased, the drainage performance by the inclined groove 43 can be improved.

  Moreover, in this invention, as shown in one Embodiment of FIG. 1, the block 7 is divided | segmented into the 1st block part 74 and the 2nd block part 75 by the connection part 43a and the sipe 52a. It is preferable. With such a configuration, it is possible to suppress stress concentration on a part of the block 7, increase the block rigidity, and improve the wear resistance.

  In the present invention, as shown in one embodiment of FIG. 1, the side wall on the outer side in the tire width direction of the first block portion 74 is more tire than the side wall on the outer side in the tire width direction of the second block portion 75. It is preferable that it is located outside in the width direction. With such a configuration, there are blocks on the tire circumferential direction line on the side wall on the outer side in the tire width direction of the second block portion 75 and on the tire circumferential direction line on the side wall on the outer side in the tire width direction of the first block portion 74. An area that does not occur is generated, and traction performance can be improved.

  In the present invention, as shown in one embodiment of FIG. 1, the first block portion 74 preferably has a tire circumferential dimension that decreases toward the outer side in the tire width direction. With this configuration, the directionality of the edge component obtained by the first block portion 74 is diversified, so that handling performance can be improved and steering stability can be improved.

  In the present invention, as shown in one embodiment of FIG. 1, in a developed view of the tread surface, the convex portion 77 is formed on the side wall 76 of the second block portion 75 defined by the circumferential main groove. Preferably, it is formed. With such a configuration, the shearing force in snow obtained by forming the region having a narrow groove width of the circumferential main groove 21 is increased, and the traction performance can be improved.

  In the present invention, as shown in one embodiment of FIG. 1, in a developed view of the tread surface, a recess 78 is formed in the side wall 76 of the second block portion 75 defined by the circumferential main groove. It is preferable that With such a configuration, since a snow shear force can be obtained in the recess 78, the traction performance can be improved.

  In the present invention, as shown in one embodiment of FIG. 1, the circumferential main groove 23 is composed of a plurality of circumferentially divided main grooves 24 divided in the tire circumferential direction. A connecting groove 25 that connects the two circumferentially divided main grooves 24 is disposed between two adjacent circumferentially divided main grooves 24. The connecting groove 25 is the first in the developed view of the tread surface. The block portion 74 is preferably disposed adjacent to the tire circumferential direction of the side wall 76 defined by the circumferentially divided main groove 24. With such a configuration, high drainage performance can be maintained by connecting the two circumferentially divided main grooves 24 adjacent to each other with the connecting groove 25. In addition, since the two adjacent circumferentially divided main grooves 24 are connected by the connecting grooves 25, even if the ratio of the tire width direction component of the grooves in the entire tread surface is reduced, high traction performance is maintained, Silence can be improved. Moreover, by arranging the connecting groove 25 adjacent to the side wall 76 defined by the circumferentially divided main groove 24, the shearing force in snow obtained can be increased and the traction performance can be improved. Therefore, quietness can be further improved while maintaining high drainage performance and traction performance.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment at all. For example, two or four or more circumferential main grooves may be formed on the tread surface. Various other modifications and changes are possible.

In order to confirm the effect of the present invention, a tire according to Examples 1 to 9 and a tire according to Comparative Examples 1 to 2 were made as trials, and a test for evaluating the performance of the tire was performed. The specifications of each tire are shown in Table 1 below. The test was performed by assembling each of the tires of the tire size 215 / 55R17 to an applicable rim and mounting the tire on a vehicle with an internal pressure of 230 kPa.

<Traction test>
About each said tire, it carried out by measuring the traction force when drive | working a farm field (muddy ground) at the speed of 5 km / h. The evaluation result of the tire according to Comparative Example 1 is evaluated with a relative value when the value is 100, and a larger numerical value indicates better traction.
<Quietness test>
About each said tire, the tire side sound at the time of making it drive | work on an indoor drum test machine at the speed of 80 km / h was measured on the conditions defined by JASO C606 standard, and air column resonance sound was evaluated. The evaluation result of the tire according to Comparative Example 1 is evaluated as a relative value when the tire is set to 100, and a larger numerical value indicates better silence.
<Drainage test>
About each said tire, it drive | worked on the wet road surface with a water depth of 6 mm on the test course, and the braking distance from a speed of 80 km / h until it brakes and stops was measured. Evaluation is based on the reciprocal of the ratio of the braking distance when the evaluation result of the tire according to Comparative Example 1 is 100, and a larger numerical value indicates better drainage.
<Abrasion test>
About each said tire, it carried out by measuring the rubber volume of the lug which lose | disappeared by the heel and toe wear after running 20000 km on the concrete road surface at the speed of 40 km / h. The evaluation result of the tire according to Comparative Example 1 is evaluated as a relative value when the value is 100, and a larger numerical value indicates better wear resistance.
<Steering stability test>
About each said tire, the driving | running | working performance at the time of drive | working on the dry road surface was evaluated by the sensory sense by a driver. The evaluation result of the tire according to Comparative Example 1 is evaluated as a relative value when the value is 100, and a larger numerical value indicates better steering stability.

  According to the present invention, it is possible to provide a pneumatic tire that can improve wear resistance and quietness while maintaining high drainage performance and traction performance.

1: tread surface 21, 22, 23: circumferential main groove, 24: circumferential divided main groove, 24a: one side end, 24b: other side end, 24c: first circumferential portion, 24d: inclined portion, 24e: second circumferential portion 25: connecting groove 25a: groove bottom 31, outer land portion 32: intermediate land portion 33: intermediate land portion 34: outer land portion 41: lug groove 42: Horizontal groove, 43: Inclined groove, 43a: Connecting part, 43b: Wide part, 43c: Narrow part, 51, 52, 52a: Sipe, 61, 62: Recessed part, 7: Block, 71: Chamfered part, 72, 73: Side wall 74: First block portion 75: Second block portion 76: Side wall 77: Convex portion 78: Concavity CL: Tire equatorial plane TE1, TE2: Tread edge

Claims (8)

The tread surface has one or more land portions sandwiched by a plurality of circumferential main grooves extending in the tire circumferential direction,
The land portion is partitioned by a transverse groove having both ends opened in the plurality of circumferential main grooves sandwiching the land portion, and a plurality of blocks are formed,
The block has an inclined groove having one end opened in the circumferential main groove, the other end terminated in the block, and extended inclined with respect to the tire circumferential direction in a developed view of the tread surface. Formed,
The inclined groove includes a connecting part connected to the circumferential main groove, a wide part connected to the connecting part, and a narrow part connected to the wide part,
In the development view of the tread surface, the wide portion and the narrow portion have a smaller inclination angle with respect to the tire circumferential direction than the connecting portion,
Wherein the block has one end opened to the connecting portion, the other end, said open to different said circumferential main grooves and the circumferential main groove connecting portion is open, are sipes formed,
In a development view of the tread surface, the sipe may have a bent portion,
The block has a chamfered portion on a side wall on an extension line in the extending direction on the other end side of the inclined groove,
The inclined groove extends to a position where the dimension in the tire circumferential direction between the inclined groove and the chamfered portion is 200% or less of the maximum dimension in the tire circumferential direction of the block in the development view of the tread surface. pneumatic tire, characterized in that is.   2. The pneumatic tire according to claim 1, wherein, in a development view of the tread surface, the groove width of the wide portion narrows toward the narrow portion. The pneumatic tire according to claim 1 or 2 , wherein the block is divided into a first block portion and a second block portion by the connecting portion and the sipe. 4. The pneumatic tire according to claim 3 , wherein a side wall on the outer side in the tire width direction of the first block portion is located on an outer side in the tire width direction on a side wall on the outer side in the tire width direction of the second block portion. . The first block portion, the dimensions of the tire circumferential direction becomes smaller toward the outside in the tire width direction, the pneumatic tire according to claim 3 or 4. In a development view of the tread surface, wherein the second block portion, the one side wall partitioned by the circumferential main grooves, projections are formed, according to any one of claims 3 to 5 Pneumatic tire. The air according to any one of claims 3 to 6 , wherein a concave portion is formed in one of the side walls of the second block portion defined by the circumferential main groove when the tread tread surface is viewed. Enter tire. At least one of the circumferential main grooves is constituted by a plurality of circumferentially divided main grooves that are divided in the tire circumferential direction and that extend in the tire circumferential direction ;
Between the two circumferentially divided main grooves adjacent to each other in the tire circumferential direction, a connecting groove extending in the tire width direction is arranged to connect the two circumferentially divided main grooves,
The connecting groove, the development view of the tread surface, wherein the first block portion, wherein the side wall defined by the circumferential-direction divided main grooves are disposed adjacent in the tire circumferential direction, of claims 3 to 7 A pneumatic tire given in any 1 paragraph.

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