JP2003054224A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire having a block pattern in a tire stepping face part and capable of improving toe and heel wear. SOLUTION: In the pneumatic tire having a blocklike tread pattern, a sipe is not arranged on a surface on a stepping in side F of a block, and a plurality of zigzag sipes S are arranged on a kicking out side K of the block 5 to prevent the communication with a lateral channel 3 adjacent to the kicking out side K of the block 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire capable of preventing uneven wear generated on a block surface of a tire tread.

[0002]

2. Description of the Related Art As a tread pattern for a pneumatic tire, a block pattern excellent in drivability and braking performance is used. The block pattern has a large number of blocks divided by a plurality of circumferential main grooves extending along the tire circumferential direction and a plurality of lateral grooves extending in the tire width direction.

A tire having such a block pattern on the tire tread surface has a shearing external force in the same block during running, on the stepping side that comes into contact with the road surface ahead of the block and the kicking side that comes into contact with the road surface later. On the other hand, on the kicking side of the block where the external shear force is greater than on the stepping side of the block, the kicking side of the block is more likely to be worn than the stepping side, and so-called toe and heel wear is likely to occur.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire having a block pattern on the tire tread, which can prevent toe and heel wear.

[0005]

In order to solve the above-mentioned problems, as a result of extensive studies, the tire of the present invention has a plurality of circumferential main grooves extending in the tire circumferential direction on the tread surface of the tire and extending in the tire width direction. Multiple lateral grooves are arranged, the main groove and the main groove,
In a pneumatic tire in which a plurality of blocks formed by a main groove and a lateral groove that respectively communicates with the outside of the shoulder ground contact end are arranged in the tire circumferential direction, and the tire rotation direction is designated as one direction, the stepping side surface of the block In the pneumatic tire, a sipe is not arranged, and a plurality of sipes having different directional components are arranged on the kick-out side surface of the block so as not to communicate with lateral grooves adjacent to the block.

By arranging a plurality of the sipes on the kicking side of the block, the rigidity of the kicking side of the block is reduced. As a result, the shearing external force applied to the kicking side during traveling is reduced, the difference between the shearing external force applied to the stepping side is reduced, the difference in the shearing external force received in the tire circumferential direction of the block is reduced, and uneven wear in the block occurs. Be improved. The reason why the sipe is arranged so as not to communicate with the lateral groove adjacent to the block is that when the sipe is arranged to communicate with the lateral groove adjacent to the block, the external shear force in the tire width direction of the block becomes large, and as a result, This is because uneven wear is not improved.

As sipes having different directional components, a polygonal line shape, a + shape, an X shape and the like are suitable. The sipe having different direction components may be arranged in the tire width direction or the tire circumferential direction.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic development view of a tire tread pattern showing an embodiment of a tire according to the present invention. Figure 1
Where R is the tire rotation direction, 1 is the tire tread surface, 2 is a vertical groove that connects the tire tread surface 1 to the tire rotation direction R, 3 is a lateral groove that extends in the tire width direction, 4 is a shoulder ground contact end, and 5 is a vertical groove 2. A block surrounded by the horizontal groove 3 or the vertical groove 2, the horizontal groove 3 and the shoulder ground contact end 4, F is the stepping side, K is the kicking side, S is the sipe, CL is the tire equator line, and 6 is the tire equator line CL. Vertical groove 21 arranged
And a rib that is sandwiched by the vertical grooves 22 arranged on the tire width direction outer side of the tire equator line CL and extends in the tire circumferential direction.

In FIG. 1, on the kick-out surface of the block,
A plurality of zigzag sipes S having different directional components are arranged on the kicking side K of the block 5 substantially in parallel to the adjacent lateral groove 3.

Sipe S with Different Directional Components of the Invention
Other examples include (a) to (f) of FIG.
However, in FIG. 2, not the entire tire tread pattern but one block in the tire tread surface and the block shape is rectangular is illustrated.

FIG. 2A is an S-shaped sipe, FIG.
(B), (c), and (f) are zigzag-shaped, and the sipe of the example different from FIG. 1, FIG.
(E) and (f) are examples of X-shaped sipes. The reference numerals in FIG. 2 are the same as those in FIG.

Next, a preferred range will be described with reference to FIG. 3 by taking a polygonal sipe as an example. In FIG. 3, a plurality of zigzag-shaped sipes S are arranged substantially parallel to the lateral groove adjacent to the kicking side K of the block 5. However, in FIG. 3, one block of the tire tread surface is used instead of the entire tire tread pattern, and the block shape is also rectangular. In FIG. 3, R is a tire rotation direction, 5 is a block, 51 is a block stepping side end, 52 is a block kicking side end, 53 and 54 are tire width direction ends of the block 5, F is a stepping side, and K is a kicking side. Side, S is sipe, A
Is a distance between the sipe S and the block kick-out side end 52, B is a tire rotation direction (circumferential direction) length of the sipe S, C is an arrangement interval between the sipes S, D is a tire width direction length of the sipe S,
E is the distance between the sipe S at the position closest to the tire width direction ends 53, 54 and the block tire width direction ends 53, 54.

The distance A between the sipe S and the block kick-out side end 52 is preferably 0.5 to 3.0 mm. A is 0.5 m
If it is less than m, the shearing force in the tire width direction becomes large, which is 3.0
If it exceeds mm, the decrease in rigidity on the kicking side is too great, and in any case, the effect of improving uneven wear is insufficient. Sipe S
Tire rotation direction (circumferential direction) length B is 4.0-6.0 m
m is desirable. When B is less than 4.0 mm, it is difficult to adopt a zigzag shape, and when it exceeds 6.0 mm, the rigidity on the kicking side is excessively decreased, and the effect of improving uneven wear is insufficient. The spacing C between the sipes S is preferably 3.0 to 7.0 mm. When C is less than 3.0 mm, the decrease in rigidity on the kicking side is too large, and when C is more than 7.0 mm, the decrease in rigidity on the kicking side is small and the effect of improving uneven wear is insufficient. The length D of the sipe S in the tire width direction is preferably 2.0 to 4.0 mm. When D is less than 2.0 mm, the difference in the direction component of the sipe is small, and the decrease in rigidity on the kicking side is small,
Even when it exceeds 4.0 mm, the difference in the direction component of the sipe is small, the rigidity on the kicking side is not significantly reduced, and the effect of improving uneven wear is insufficient. The distance E between the sipe S closest to the tire width direction ends 53, 54 of the block and the tire width direction ends 53, 54 of the block is preferably 3 to 5 mm. If E is less than 3 mm, the decrease in rigidity is too large.
If it exceeds mm, the decrease in rigidity is too small. In the present invention, usually, the sipe width is 0.3 to 0.6 mm and the sipe depth is 1/2 of the lateral groove depth adjacent to the block.

[0014]

EXAMPLES Next, as an example, tire size 205 /
55R16, using the tire of the schematic development view shown in FIG. 1 as a tread pattern, as Comparative Examples 1 and 2 for comparison,
A tire size of 205 / 55R16 was used, and as the tread pattern, tires having the schematic development views shown in FIGS.
At 300 kpa, load 3 per tire when mounted on the vehicle
After running for 12,000 km at 20 kg, the difference in the amount of wear between the stepped-in side and the kicked-out side of the block after running was measured, and the reciprocal of this value was indexed with the example tire as 100. The larger the number, the better.

In each of the embodiment, the comparative example 1 and the comparative example 2, the distance between the sipe and the end of the block kicking side (A in FIG. 3).
Is equivalent to 1.5 mm for blocks at both ends (shoulder part) in the tire width direction, 1.5 mm for blocks on the inner side in the tire width direction (tire equator line side), and the end of the sipe on the stepping side (corresponding to 51 in FIG. 3). 20m at both ends (shoulder) block in the tire width direction
m, 20 mm in the block on the tire width direction inner side (tire equator line side), and the arrangement range of the sipes in the tire circumferential direction (B in FIG. 3).
Is equivalent to 5 mm in both end portions (shoulder portions) in the tire width direction, 5 mm in the tire width direction inner side (tire equator line side) block, and sipe depth is in Example, In both Comparative Example 1 and Comparative Example 2, 3 mm in both end portions (shoulder portion) blocks in the tire width direction and blocks in the tire width direction inner side (tire equator line side).
The sipe width is 0.3 m in both the tire width direction both end portions (shoulder portions) block and the tire width direction inner side (tire equator line side) block in the examples, the comparative examples 1 and the comparative example 2.
m, flute depth was 8.2 mm at any location in all of Examples, Comparative Examples 1 and 2, and lateral groove depth was 6.7 mm at any location in Examples, Comparative Examples 1 and 2.
And

The evaluation results are shown in Table 1.

[Table 1]

From Table 1, the tires of the examples according to the present invention are
It is recognized that the uneven wear resistance is improved as compared with the comparative tire.

[0018]

As described in detail above, in the pneumatic tire of the present invention, a plurality of circumferential main grooves extending in the tire circumferential direction and a plurality of lateral grooves extending in the tire width direction are arranged on the tread surface of the tire. In a pneumatic tire in which a plurality of blocks formed by a main groove and a main groove, a lateral groove that communicates with the main groove and a shoulder ground contact end outside, respectively, are arranged in the tire circumferential direction, and the tire rotation direction is designated as one direction, No sipe is arranged on the stepping side surface of the block, and a plurality of sipes having different directional components are arranged on the kicking side surface of the block so as not to communicate with the lateral groove adjacent to the block, so that the kicking out at the time of running The shearing external force applied to the side is reduced, the difference between the stepping side and the shearing external force is reduced, and the difference in the shearing external force received in the tire circumferential direction of the block is reduced. Uneven wear in the lock is improved.

[0019]

[Brief description of drawings]

FIG. 1 is a schematic development view of a tire tread pattern showing an embodiment of a tire according to the present invention.

2A to 2F are partial schematic views of a tire tread pattern showing another embodiment of the tire according to the present invention.

FIG. 3 is a partial schematic view of a tire tread pattern showing an embodiment of a tire according to the present invention.

FIG. 4 is a schematic development view of a tire tread pattern of a conventional tire.

FIG. 5 is a schematic development view of a tire tread pattern of a conventional tire.

[Explanation of symbols]

1 tire tread surface 2 vertical groove 3 lateral grooves 4 shoulder ground edge 5 blocks F stepping side K kicking side S sipe R Tire rotation direction

Claims (5)

[Claims] 1. A tread surface of a tire is provided with a plurality of circumferential main grooves extending in the tire circumferential direction and a plurality of lateral grooves extending in the tire width direction. The main groove communicates with the main groove, and the main groove communicates with the outside of the shoulder ground contact end. With a plurality of blocks formed by the lateral groove to be arranged in the tire circumferential direction, in a pneumatic tire in which the tire rotation direction is designated as one direction, the sipe is not arranged on the stepping side surface of the block, A pneumatic tire characterized in that a plurality of sipes having different directional components are arranged on the kick-out side surface so as not to communicate with lateral grooves adjacent to the block. 2. The pneumatic tire according to claim 1, wherein the sipes having different directional components are linear. 3. The pneumatic tire according to claim 1, wherein the sipes having different directional components are + -shaped or X-shaped. 4. The pneumatic tire according to claim 1, wherein sipes having different directional components are arranged in the tire width direction. 5. The pneumatic tire according to claim 1, wherein sipes having different directional components are arranged in the tire circumferential direction.