JPS6350204B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a tire for a two-wheeled vehicle, and particularly to a tire for a two-wheeled vehicle that can improve cornering characteristics on a wet road surface.

In the first place, when a two-wheeled vehicle is cornering, it is necessary to tilt the vehicle body G from the state shown in Fig. 1 a to the state shown in Fig. 1 b in accordance with the speed, and as a result, the tire contact surface changes from the state shown in Fig. 1 c. From the state shown in Figure d, it moves from the center in the width direction of the tire in the axial direction. Therefore, as shown in Figure d, the road surface grip (grip) on the contact surface outside 1/3 of the tire tread width is an important factor in cornering performance. Particularly when cornering on a wet road surface, such as during rain, water is present between the tire contact patch and the road surface, which reduces the gripping force of the tread and may cause the tire to slip, which is unfavorable for safety. .

The main factors that improve the tire's tread grip are:
The quality of the material of the tire's tread rubber and the pattern formed on the tread surface.If the materials are the same, the quality of the pattern will affect the aforementioned tread gripping force, especially the tread gripping force on a wet road surface. In order to improve this, it is desirable to have a pattern that can improve the drainage effect on the tire contact surface.

However, during conventional cornering,
As shown in FIGS. 2a and 2b, the pattern formed on the tire contact surface in contact with the ground consists of the groove depth 3 of the circumferential groove 1 continuously provided in the circumferential direction of the tire, and the circumferential groove 1. Since the groove depths 4 of the plurality of axial grooves 2, one of which is open at the tire axial direction end portion (tire width direction end portion) and the other end of which is opened at the tire axial direction end portion (tire width direction end portion) 2a, are the same, cornering on a wet road surface is facilitated. At this time, the water pushed out into the axial groove 2
However, since the water pushed into the circumferential groove 1 is drained through each axial groove 2, the water near each axial groove 2 is ignored. , the water pushed out to the middle part of the circumferential groove 1 separated by each axial groove 2 is difficult to drain, and the pattern as a whole has extremely poor drainage performance, thus making it difficult to grasp the tread on a wet road surface. The current situation is that there is a major problem in that power is significantly reduced.

The present invention has been made in view of the above-mentioned current situation, and an object of the present invention is to provide a tire for a two-wheeled vehicle that solves the above-mentioned problems.

The feature is that the drainage effect of the circumferential groove is improved by increasing the groove depth of the circumferential groove toward each axial groove provided in communication with the circumferential groove. This significantly improves cornering characteristics on wet road surfaces.

The present invention will be explained below by way of examples with reference to the drawings.

Figure 3 a, b, c (first embodiment) and Figure 4 a,
As shown in b and c (second embodiment), when the motorcycle tire E according to the present invention is tilted during cornering, the contact surface of the tire that contacts the ground, that is, the surface of the shoulder portion of the tire, , for a two-wheeled vehicle, comprising a circumferential groove 1 continuous in the circumferential direction of the tire, and a plurality of axial grooves 2, one of which is open in the circumferential groove 1 and the other of which is open to the axial end 2a of the tire. In the tire, each of the axial grooves 2 is provided so that a groove depth 3 in each section A of the circumferential groove 1 separated by each of the axial grooves 2 is communicated with the circumferential groove 1. and the groove depth 4 of each axial groove 2 is
The groove depth is made equal to or greater than the maximum groove depth of the circumferential groove 1.

FIG. 3a shows an embodiment in which the circumferential groove 1 is formed in a zigzag shape, and in this embodiment, the aforementioned groove depth changes as shown in FIG.
The axial groove 2 is deepened linearly from the center to the center line of the axial groove 2 to the left and right. However, this change in groove depth is not limited to a straight line, but may also be changed in a curved manner, for example, as shown in FIG.

Moreover, FIGS. 4a, b, and c show an embodiment in which the circumferential groove 1 is formed into a linear shape.

Note that the arrows shown in FIGS. 3a and 4a indicate the direction of water flow.

The groove depth of the axial groove 2 and the groove depth of the intermediate part in each section A of the circumferential groove 1 are as follows: groove depth of the axial groove ≧1.1×(groove depth of the intermediate part in section A) Preferably in a relationship.

Further, the maximum groove depth in each section A of the circumferential groove 1 is preferably about 6 mm or less. This is because the deeper the depth of each of the grooves, the greater the drainage capacity when driving on a wet road surface, the better the grip force, and the better the cornering performance on a wet road surface. 1 and each axial groove 2
This is because the axial rigidity of each block B surrounded by the block B is reduced, and the block B is excessively deformed during cornering, which in turn reduces the cornering performance.

However, in the present invention, the groove depth of each groove is not uniformly deep as shown in FIGS. 3b, c and 4b, c, so that the axis of each block B is The drainage effect can be improved without reducing the directional rigidity.

Next, the tire according to the present invention and the conventional tire were mounted on an actual two-wheeled vehicle, and the tire radius was measured on a wet road surface.
We will explain the results of a 30m cornering test.

The tires of the present invention and the conventional tires used in this test had zigzag circumferential grooves as shown in Figure 3a, and in the case of the tire of the present invention,
The maximum groove depth of each axial groove 2 was set to 1.4 times the groove depth at the center of each section A of the circumferential groove 1, and the groove depth was gradually increased linearly as shown in Fig. 3b. I used something. The other dimensions used were the same for both the conventional tire and the tire of the present invention.

As a result of a cornering test with a radius of 30 m on a wet road surface using each of the tires described above, as shown in Fig. 5, the maximum cornering speed possible was 1.8 Km/h, or about 5% lower than the present invention. The cornering performance of the tires improved.

Also, in a feeling test on a wet road surface, the tires according to the present invention had better grip and less slippage than conventional tires.

As described above, the present invention deepens the groove depth in each section divided by each axial groove of the circumferential groove toward the axial groove, and also increases the groove depth of each axial groove. Since the groove depth is equal to or greater than the maximum groove depth of the circumferential groove, the drainage effect of the circumferential groove can be improved without reducing the axial rigidity of each block formed by the circumferential groove and each axial groove. can be significantly improved.

Therefore, the present invention can significantly improve the cornering characteristics on a wet road surface without impairing the cornering characteristics on a dry road surface.

[Brief explanation of the drawing]

Figures 1 a, b, c, and d are explanatory diagrams comparing the contact surfaces of tires for two-wheeled vehicles when traveling straight and when cornering. Figures 2 a and b are diagrams showing the contact surfaces of conventional motorcycle tires on wet roads. An explanatory diagram showing the partial pattern of the tire contact surface during cornering, the drainage situation (Figure A), and the groove depth of each groove (Figure B),
Figures 3 and 4 show examples of the present invention, and Figure 3a shows the partial pattern of the tire contact patch and the water drainage situation when the tire is cornering on a wet road surface in the first example. An explanatory diagram to explain,
b and c are explanatory diagrams showing the groove depth of each groove in Fig. 4a, respectively. Fig. 4a is a partial pattern of the tire contact surface and drainage situation during cornering on a wet road surface of the tire in the second embodiment. FIG. 5 is an explanatory diagram illustrating the groove depth of each groove in FIG. be. 1... Circumferential groove, 2... Axial groove, A... Section, 2a... Tire axial end, 3... Groove depth of circumferential groove, 4... Groove depth of axial groove.

Claims (1)

[Claims] 1. Two wheels equipped with a circumferential groove continuous in the circumferential direction of the tire on the surface of the shoulder portion of the tire, and a plurality of axial grooves with one opening in the circumferential groove and the other opening in the axial end of the tire. In the automobile tire, the groove depth in each section of the circumferential groove divided by each axial groove is deepened toward the axial groove, and the groove depth of each axial groove is , a two-wheel vehicle tire formed to have a groove depth equal to or greater than the maximum groove depth of the circumferential groove.