JP2007015511A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire improving traveling performance on ice, and steering stability and wear resistance on a dry road surface. <P>SOLUTION: In the pneumatic tire designating an installing direction of tire back and front sides to a vehicle, a tread portion 1 is provided with a main groove 11 extending in a tire circumferential direction, a main groove 12 extending in the tire circumferential direction in a shoulder area on the inner side of a vehicle than the main groove 11, a main groove 13 extending in the tire circumferential direction in the shoulder area on the outer side of the vehicle than the main groove, and a plurality of lug grooves 14 extending from one shoulder side to the other shoulder side. The width of a land part 21 divided between the main groove 11 and the main groove 12 is made to be wider than that of a land part 22 divided between the main groove 11 and the main groove 13. A plurality of tilting grooves 15 communicating to at least three lug grooves 14 while tilting in the tire circumferential direction is provided on the land part 21. One end 15a of the tilting groove 14 is opened to the lug groove 14 and the other end 15b is terminated in a block. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire suitable as a studless tire, and more particularly to a pneumatic tire that improves running performance on snow and improves driving stability and wear resistance on a dry road surface.

Generally, in a pneumatic tire, it is difficult to achieve both running performance on snow and running performance on a dry road surface. For example, in a pneumatic tire for icy and snowy roads, a tread portion is provided with a plurality of main grooves extending in the tire circumferential direction and a plurality of lug grooves extending in the tire width direction, and a plurality of blocks are partitioned by the main grooves and the lug grooves. (For example, refer to Patent Document 1). In such a pneumatic tire for icy and snowy roads, it is possible to exhibit excellent running performance on snow by setting a large groove area, but usually a soft tread rubber is used, so the block rigidity is The current situation is that the driving stability and wear resistance on dry road surfaces are not always sufficient.
JP 2004-34909 A

  An object of the present invention is to provide a pneumatic tire capable of improving running performance on snow and improving driving stability and wear resistance on a dry road surface.

  In order to achieve the above object, a pneumatic tire according to the present invention includes a first main groove extending in a tire circumferential direction at a tread portion and a first main groove in a pneumatic tire in which a tire front and back mounting direction with respect to a vehicle is specified. A second main groove extending in the tire circumferential direction in the shoulder region inside the vehicle, a third main groove extending in the tire circumferential direction in the shoulder region outside the vehicle from the first main groove, and the other shoulder from one shoulder side A plurality of lug grooves extending to the side, and the width of the first land portion defined between the first main groove and the second main groove is defined between the first main groove and the third main groove. The first land portion is provided with a plurality of inclined grooves communicating with at least three lug grooves while being inclined with respect to the tire circumferential direction, and one end of the inclined groove is formed on the first land portion. That the other end is terminated in the block while opening in the lug groove It is an butterfly.

  In the present invention, the tread portion is divided into a plurality of rows of land portions by the first main groove, the second main groove, and the third main groove, and the width of the first land portion inside the vehicle is set to the width of the second land portion outside the vehicle. The long slope groove is arranged in the 1st land part. With the above configuration, the block rigidity can be optimized, steering stability and abrasion resistance on the dry road surface can be sufficiently ensured, and steering stability on snow based on the inclined grooves arranged in the first land portion And traveling performance such as turning performance can be improved.

  In the present invention, it is preferable to adopt the following configuration in order to achieve both the running performance on snow and the steering stability and wear resistance on the dry road surface.

That is, the inclined groove communicates with the three lug grooves, and the four types of blocks divided by the three lug grooves and the inclined grooves are arranged in the first land portion as repeating units, and a plurality of blocks are provided in the second land portion. A plurality of blocks partitioned by a single lug groove are arranged, the surface area Sa of the block A located on the other end side of the inclined groove on the inner side of the vehicle on the first land portion, and one end of the inclined groove on the inner side of the vehicle on the first land portion The surface area Sb of the block B located on the side, the surface area Sc of the block C located on the other end side of the inclined groove outside the first land portion, and the block located on one end side of the inclined groove outside the first land portion of the vehicle The surface area Sd of D, the surface area Se of the block E adjacent to the block C in the second land part, and the surface area Sf of the block F adjacent to the block D in the second land part may be set as follows.
Sa = Se × 92% to 100%
Sb = Sf × 110% to 118%
Sc = Se × 110% to 115%
Sd = Sf × 95% to 100%

Further, the groove width x1 at the vehicle inner side portion in the first land portion of the lug groove, the groove width x2 between the inclined grooves in the first land portion, the groove width x3 at the vehicle outer portion in the first land portion are as follows: It is good to have a relationship.
x2 = x1 × 101% to 180%
x3 = x1 × 60% to 99%

  Furthermore, the width of the first land portion is set to 50% to 70% of the ground contact half width, and the width of the second land portion is set to 15% to 35% of the ground contact half width. The groove width y1 is set to 40 to 50% of the groove width y2 in the vehicle inner portion in the second land portion, the inclination angle of the inclined groove with respect to the tire circumferential direction is set to 10 ° to 30 °, and the first The total groove width of the main groove, the second main groove, and the third main groove is set to 15% to 35% of the tread ground contact width, which means that the running performance on snow, the handling stability on the dry road surface, and the wear resistance It is effective in achieving both.

  In the present invention, when configuring a pneumatic tire for an icy and snowy road represented by a studless tire, it is preferable to provide a plurality of sipes extending in the tire width direction in each land portion including the first land portion and the second main groove. . The present invention provides a remarkable effect when applied to a pneumatic tire for icy and snowy roads, but can also be applied to a pneumatic tire for all seasons.

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

  FIG. 1 shows a tread pattern of a pneumatic tire for icy and snowy roads according to an embodiment of the present invention. In the pneumatic tire of this embodiment, the mounting direction of the tire front and back with respect to the vehicle is specified. In FIG. 1, IN is the vehicle inner side, and OUT is the vehicle outer side.

  As shown in FIG. 1, the tread portion 1 includes a main groove 11 (first main groove) extending in the tire circumferential direction in the tread central region, and a main groove extending in the tire circumferential direction in a shoulder region inside the vehicle from the main groove 11. A groove 12 (second main groove), a main groove 13 (third main groove) extending in the tire circumferential direction in a shoulder region outside the vehicle from the main groove 11, and a plurality of grooves extending from one shoulder side to the other shoulder side Lug grooves 14 are formed. The lug grooves 14 are curved and inclined in one direction with respect to the tire width direction, and are arranged at intervals in the tire circumferential direction. Thereby, a land portion 21 (first land portion) is defined between the main groove 11 and the main groove 12, and a land portion 22 (second land portion) is defined between the main groove 11 and the main groove 13. Further, a land portion 23 (third land portion) is defined outside the main groove 12 in the tire width direction, and a land portion 24 (fourth land portion) is defined outside the main groove 13 in the tire width direction. ing. And the width of the land portion 21 is larger than the width of the land portion 22.

  A plurality of inclined grooves 15 that communicate with the three lug grooves 14 while being inclined with respect to the tire circumferential direction are formed in the land portion 21. One end 15a of the inclined groove 15 opens into the lug groove 14, and the other end 15b terminates in the block. In particular, the inclined groove 15 is inclined in the direction opposite to the lug groove 14 and is disposed so that the other end 15b terminating in the block faces the vehicle inside. Thereby, in the land part 21, four types of blocks having different shapes defined by the three lug grooves 14 and the inclined grooves 15 are arranged as repeating units. In addition, a plurality of blocks partitioned by the lug grooves 14 are arranged in the land portions 22 to 24, respectively.

  Each block included in the land portions 21 to 24 is formed with a plurality of sipes 16 extending in the tire width direction. The shapes of these sipes 16 are not particularly limited, and those having a zigzag shape or a linear shape in a plan view, or those having a three-dimensional shape can be employed.

  In the pneumatic tire, the tread portion 1 is divided into four rows of land portions by the three main grooves 11 to 13, and the width of the land portion 21 on the vehicle inner side is made larger than the width of the land portion 22 on the vehicle outer side, By providing the long inclined groove 15 with respect to the wide land portion 21, the block rigidity is optimized, so that the steering stability and the wear resistance on the dry road surface can be sufficiently ensured. Moreover, traveling performance such as steering stability and turning performance on snow can be improved based on the inclined groove 15 of the land portion 21.

In the pneumatic tire, the surface area Sa of the block A located on the other end side of the inclined groove 15 on the vehicle inner side of the land portion 21, and the surface area Sb of the block B located on the one end side of the inclined groove 15 on the vehicle inner side of the land portion 21. The surface area Sc of the block C located on the other end side of the inclined groove 15 outside the land portion 21, the surface area Sd of the block D located on the one end side of the inclined groove 15 outside the vehicle of the land portion 21, The surface area Se of the block E adjacent to the block C and the surface area Sf of the block F adjacent to the block D in the land portion 22 are set as follows.
Sa = Se × 92% to 100%
Sb = Sf × 110% to 118%
Sc = Se × 110% to 115%
Sd = Sf × 95% to 100%

  By defining the block surface area in the land portion 21 as described above, and mixing blocks A to D constituting one unit with four types so that relatively large blocks C and D are diagonally positioned, It is possible to improve the running performance of the vehicle and the running performance on snow in a well-balanced manner.

  The width W1 of the land portion 21 is set to 50% to 70% of the ground half width, and the width W2 of the land portion 22 is set to 15% to 35% of the ground half width. By setting the width of the land portions 21 and 22 within the above range, it is possible to improve the running performance on the dry road surface and the running performance on the snow in a well-balanced manner. When the width W1 of the land portion 21 is less than the above range, the inclination of the inclined groove 15 becomes insufficient and the steering stability on the snow is lowered. When the width W2 of the land portion 22 is below the above range, the maneuvering on the dry road surface is performed. Stability and turning performance are reduced. The contact half width is the air pressure-load capacity correspondence table specified in the JATMA Yearbook (2004 edition). The tire is filled with the air pressure corresponding to the maximum load capacity and multiplied by 80% of the load capacity. Is a half of the tread contact width TCW measured in the tire axial direction.

The groove width of the lug groove 14 is optimized according to the position in the tire width direction. That is, as shown in FIG. 2, the groove width x1 of the lug groove 14 in the vehicle inner portion in the land portion 21, the groove width x2 between the inclined grooves 15 and 15 in the land portion 21, and the vehicle in the land portion 21. The groove width x3 at the outer portion is set to the following relationship. However, when the lug groove 14 is locally expanded by chamfering the block at the communication portion with the main groove, the groove widths x1 and x3 are the groove widths of the portion excluding the enlarged portion.
x2 = x1 × 101% to 180%
x3 = x1 × 60% to 99%

  By reducing the groove width x3 in this manner, the groove area in the tread central region can be reduced, and the running performance on dry road surface and ice can be improved, and the groove width x2 between the inclined grooves 15 and 15 is increased. By doing so, it is possible to improve steering stability and turning performance on snow.

  As shown in FIG. 3, the groove width y <b> 1 at the vehicle outer side portion in the land portion 22 of the lug groove 14 is set to 40 to 50% of the groove width y <b> 2 at the vehicle inner portion in the land portion 22. By making the groove width y1 narrower than the groove width y2, the running performance on the dry road surface and the running performance on snow can be improved in a balanced manner. When the groove width y1 exceeds the above range, the turning performance on the dry road surface decreases, and conversely, when the groove width y1 falls below the above range, the traction performance on snow decreases. In addition, when placing importance on dry performance, the lug groove 14 may be closed in the middle of the land portion 22 (see FIG. 4).

  The inclination angle θ of the inclined groove 15 with respect to the tire circumferential direction is set to 10 ° to 30 °. When the inclination angle θ of the inclined groove 15 is larger than the above range, the dimensional difference between the blocks in the land portion 21 becomes large and the block rigidity becomes non-uniform so that the uneven wear resistance is reduced. When turning, the effect of the inclined groove 15 cannot be sufficiently exhibited, and the steering stability on snow is lowered.

  The total groove width of the main grooves 11 to 13 is set to 15% to 35% of the tread ground contact width TCW. When the sum of the groove widths of the main grooves 11 to 13 is less than 15% of the tread ground contact width TCW, the wet performance is lowered, and conversely, when it exceeds 35%, the steering stability on the dry road surface is lowered.

  In the pneumatic tire for snowy and snowy roads having a tire size of 205 / 55R16, tires of a conventional example and Examples 1 and 2 in which only the tread pattern was varied were manufactured.

  In the conventional example, five main grooves extending in the tire circumferential direction and a plurality of lug grooves extending in the tire width direction are provided in the tread portion, and a number of rectangular blocks are partitioned by these main grooves and lug grooves. is there. On the other hand, Example 1 has a tread pattern shown in FIG. 1, and Example 2 has a tread pattern shown in FIG.

  These test tires were evaluated for steering stability on a dry road surface, steering stability on snow, turning performance on snow, and wear resistance by the following test methods, and the results are shown in Table 1.

Steering stability on dry roads:
The test tire was mounted on a wheel having a rim size of 16 × 6.5 J, mounted on a rear-wheel drive vehicle with a displacement of 2000 cc with an air pressure of 200 kPa, and sensory evaluation was performed by a test driver on a dry road test course. The evaluation results are shown as an index with the conventional example being 100. The larger the index value, the better the steering stability on the dry road surface.

Steering stability on snow:
The test tire was mounted on a wheel having a rim size of 16 × 6.5 J, mounted on a rear-wheel drive vehicle having a displacement of 2000 cc with an air pressure of 200 kPa, and sensory evaluation was performed by a test driver on a test course on snow. The evaluation results are shown as an index with the conventional example being 100. The larger the index value, the better the handling stability on snow.

Swirl on snow:
The test tire was mounted on a wheel having a rim size of 16 × 6.5 J, mounted on a rear-wheel drive vehicle having a displacement of 2000 cc with an air pressure of 200 kPa, and sensory evaluation was performed by a test driver on a test course on snow. The evaluation results are shown as an index with the conventional example being 100. The larger the index value, the better the turning performance on snow.

Abrasion resistance:
The test tire is mounted on a wheel with a rim size of 16 x 6.5 J, mounted on a rear-wheel drive vehicle with a displacement of 2000 cc with an air pressure of 200 kPa, and after running about 10,000 km on a dry road, the amount of wear at the tread center position is measured. did. The evaluation results are shown as an index with the conventional example being 100, using the reciprocal of the measured value. A larger index value means better wear resistance.

  As can be seen from Table 1, the tires of Examples 1 and 2 have excellent driving stability on a dry road surface, driving stability on snow, turning on snow, and wear resistance in comparison with the conventional example. It was.

It is an expanded view which shows the tread pattern of the pneumatic tire for snowy and icy roads which consists of embodiment of this invention. It is a top view which expands and shows the 1st land part in FIG. It is a top view which expands and shows the 2nd land part in FIG. It is an expanded view which shows the tread pattern of the pneumatic tire for icy and snowy roads which consists of other embodiment of this invention.

Explanation of symbols

1 tread 11 main groove (first main groove)
12 Main groove (second main groove)
13 Main groove (3rd main groove)
14 Lug groove 15 Inclined groove 15a One end of inclined groove 15b Other end of inclined groove 16 Sipe 21 Land part (first land part)
22 Land (second land)
23 Land (Third Land)
24 Land (4th Land)
A to F block

Claims (8)

  In a pneumatic tire in which a tire front and back mounting direction with respect to a vehicle is specified, a tread portion includes a first main groove extending in the tire circumferential direction, and a second extending in the tire circumferential direction in a shoulder region on the vehicle inner side than the first main groove. A main groove, a third main groove extending in the tire circumferential direction in a shoulder region outside the vehicle from the first main groove, and a plurality of lug grooves extending from one shoulder side to the other shoulder side; The width of the first land portion partitioned between the groove and the second main groove is made larger than the width of the second land portion partitioned between the first main groove and the third main groove, A plurality of inclined grooves communicating with at least three lug grooves while being inclined with respect to the tire circumferential direction are provided in the land portion, and one end of the inclined groove is opened in the lug groove while the other end is terminated in the block. A pneumatic tire characterized by that. The inclined groove communicates with three lug grooves, and four types of blocks defined by the three lug grooves and the inclined grooves are arranged in the first land portion as repeating units, and the second land A plurality of blocks partitioned by the plurality of lug grooves in a portion, a surface area Sa of a block A located on the other end side of the inclined groove on the vehicle inner side of the first land portion, the vehicle of the first land portion The surface area Sb of the block B located on one end side of the inclined groove on the inner side, the surface area Sc of the block C located on the other end side of the inclined groove on the outer side of the first land portion, and inclined on the outer side of the vehicle of the first land portion The surface area Sd of the block D located at one end of the groove, the surface area Se of the block E adjacent to the block C in the second land portion, the surface area Sf of the block F adjacent to the block D in the second land portion,
Sa = Se × 92% to 100%
Sb = Sf × 110% to 118%
Sc = Se × 110% to 115%
Sd = Sf × 95% to 100%
The pneumatic tire according to claim 1, wherein the relationship is A groove width x1 at the vehicle inner side portion in the first land portion of the lug groove, a groove width x2 between the pair of inclined grooves in the first land portion, and a groove width x3 at the vehicle outer portion in the first land portion,
x2 = x1 × 101% to 180%
x3 = x1 × 60% to 99%
The pneumatic tire according to claim 1 or 2, wherein the relationship is as follows.   The pneumatic tire according to any one of claims 1 to 3, wherein the width of the first land portion is 50% to 70% of the ground contact half width, and the width of the second land portion is 15% to 35% of the ground contact half width. .   The air according to any one of claims 1 to 4, wherein a groove width y1 at a vehicle outer side portion in the second land portion of the lug groove is 40 to 50% of a groove width y2 at a vehicle inner portion in the second land portion. Enter tire.   The pneumatic tire according to any one of claims 1 to 5, wherein an inclination angle of the inclined groove with respect to a tire circumferential direction is 10 ° to 30 °.   The pneumatic tire according to any one of claims 1 to 6, wherein a total sum of groove widths of the first main groove, the second main groove, and the third main groove is 15% to 35% of a tread ground contact width. The pneumatic tire according to any one of claims 1 to 7, wherein a plurality of sipes extending in a tire width direction are provided in each land portion including the first land portion and the second main groove.

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