JPH0274405A - Motorcycle tire on rough terrain - Google Patents

Abstract

PURPOSE:To improve gripping force of a tire in its cornering by forming outer section surfaces of a block inside the outmost block with No.1 and No.2 inclined surface having a fixed relationship between them and setting specified values to the length of both inclined surfaces and the outer surface of a tread. CONSTITUTION:In a block 2 inside the outmost block 1 in the lateral direction of a tire, an inclined angle alpha1 of No.1 inclined surface 3a of the outer section surface 3 to a tread surface normal line and an inclined angle theta2 of No.2 inclined surface 3b to a tread surface normal line are relatively set as 3alpha2>alpha1>1.5alpha2 under the condition of 30 deg.>alpha2>10 deg.. An intersection A1 of No.1 inclined surface 3a with a tread surface 4, an intersection A2 of a virtually extended surface of No.2 inclined surface 3b with the tread surface 4, and an intersection B of the inner section surface 6 of a block 2 with the tread surface 4 are relatively set as tread surface length between A2 and B X 0.4 < tread surface length between A1 and B < tread surface length between A2 and B X 0.7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in a two-wheeled vehicle tire for rough terrain, and in particular, to a tire that significantly improves cornering characteristics.

(Prior art) A normal two-wheeled tire for rough terrain has a plurality of blocks located on the tread surface at predetermined intervals in the tire circumferential direction and width direction. The tire's grip is brought about by the action of the block edges.

(Problem to be Solved by the Invention) However, in such conventional tires, the blocks are generally
Because they are arranged relatively sparsely in the tire circumferential direction and relatively densely in the tire width direction, it is especially important to give the tire a large camber angle and position it on the outermost side in the tire width direction. When trying to obtain tire grip from the inner edge of the block in the tire width direction, the block located inside the outermost block, and by extension the outer shoulder of that block, also comes into contact with the ground together with the outermost block. Therefore, there is a tendency that the edge cannot be applied sufficiently, and as a result, there is a risk that the tire may drift during cornering.

The present invention advantageously solves the problems of the prior art, and provides a two-wheeled vehicle tire for rough terrain that can greatly improve the grip of the tire during cornering.

(Means for Solving the Problems) The two-wheeled vehicle tire for rough terrain of the present invention is particularly characterized in that the block located inside the outermost block in the width direction of the tire has an outer partition surface that is connected to the first block adjacent to the tread surface. and a second inclined surface adjacent to the tread bottom, the first inclined surface having an inclination angle α with respect to the tread surface normal.
, and the inclination angle α2 of the second inclined surface with respect to the normal to the trend surface is set as 3α2>α, >1.5α2 under 30°>αz>10′, and Intersection line A between the first slope surface and the trend surface, intersection line A2 between the virtual extension surface of the second slope surface and the tread surface, and intersection line B between the inner partition surface of the block and the tread surface. Tread surface length between At-8 Xo, 4 <A, tread surface length between ~B <A2~
The tread surface length between B x 0.7.

(Function) In the present invention, by forming the outer partition surface of the block located inside the outermost block with the first and second inclined surfaces having a certain relative relationship, the pro- Since it is possible to very effectively prevent ground contact, the inner edge of the outermost block can be sufficiently applied to generate a large gripping force.

Moreover, here, in addition to the above-mentioned constant relative relationship between the first and second inclined surfaces, in a block having an outer dividing surface consisting of both slopes, the inner dividing surface and the first inclined surface are By setting the tread surface length between the blocks to a predetermined value, it is possible to prevent a decrease in the rigidity of the blocks and to sufficiently ensure the performance of various tire performances.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a developed view illustrating a tread pattern of a tire according to the present invention, and FIG. 2 is a meridian cross-sectional view of the tire taken along the line ■-■ in FIG.

Note that since the internal structure of the tire is not the gist of the present invention, illustration thereof is omitted here.

As is clear from FIG. 1, this tire has a plurality of blocks BL located on the tread surface at predetermined intervals in the circumferential direction and width direction of the tire.

Here, among these blocks BL, in the block 2 located inside the outermost block 1 in the tire width direction, its outer partition surface 3 is defined as the first slope surface 3a adjacent to the tread surface 4, the second adjacent to the tread bottom 5;
306. Under the condition of 〉α2〉10°, 3α2〉αclear〉1.5α2.

Here, if 30°〉αt>10” and α2 is 10
If α2 is less than 30', the rigidity of the block against lateral force during cornering will decrease, and if α2 is more than 30', the block rigidity will be more than necessary and sufficient, and conversely, it will cause an increase in weight. 3α2〉α, >1,5 α
The reason why it is set at 2 is because if α1 is less than 1.5α2 or more than 3α2, the block edge effect intended by the present invention is insufficient.

In addition, here, an intersection line A of the first inclined surface 3a with the tread surface 4, an intersection line A2 of the virtual extension surface of the second inclined surface 3b with the tread surface 4, and an inner section of the block 2 are shown. Screen 6
and the intersection line B with the trend surface 4, the tread surface length between A2 and B is Xo, 4 <A, the tread surface length between B and the tread surface length between A and B x 0. Set it to 7.

Here, the tread surface length between A1 and B is set in this range because if the length is less than 40% of the tread surface length between A2 and B, the tread surface area becomes too small.
This is because the contact area with the road surface becomes too small and the grime effect becomes low, and at 70% or more of the trend surface length between A2 and B, the block edge effect intended by this invention is insufficient. .

[Comparative example]

Below, a comparative test regarding traction performance, cornering grip performance, controllability, and ramp time between the tire according to the present invention and a conventional tire will be explained.

Test tire size 110/100-18 - Inventive tire In a tire having the tread pattern shown in Figure 1.2, the inclination angle α1 is 556, the inclination angle α is 24°, and between A and B. The tread surface length of A2
The length was set to be 55% of the tread surface length between ~B.

- Conventional tire In a tire having a tread pattern similar to that shown in Fig. 1.2, the inclination angle α2 was set to 24°.

Test Method - Two riders with international A-class licenses ran the vehicle to evaluate the feeling of each performance and measure ramp time.

The results of these tests are shown in the following table using an index with the conventional tire set as an index of 100. Here, it is assumed that the larger the index value, the better the result.

table can be improved.

[Brief explanation of the drawing]

FIG. 1 is a developed view illustrating a tread pattern of a tire according to the present invention, and FIG. 2 is a meridian cross-sectional view of the tire taken along the line ■-■ in FIG. 1... Outermost block 2... Block 3a.
...First inclined surface 3b...Second inclined surface 3.
...Outer section screen 4...Tread surface 5...
-Tread bottom 6...inner partition surface According to this table, the invented tire can significantly improve both cornering grip and controllability compared to conventional tires without causing a decrease in traction performance. is obvious. (Effects of the Invention) Thus, according to the present invention, cornering characteristics can be significantly improved with little or no effect on traction performance, and controllability can also be significantly improved. Company Bridgestone/-1-・Outermost port 17 2-----7-RO/RI 3a-=3ijl's i #fIai 3b-----rule 2o inclined surface 3----- f) A member・1 section - ri 6m 4 ---- Tre FA side 5 --- 1 tren I''kuon y 6 ---- Inner section screen

Claims (1)

[Claims] 1. In a two-wheeled tire formed by forming a plurality of blocks located on the tread surface at predetermined intervals in the circumferential direction and width direction of the tire, on the inside of the outermost block in the width direction of the tire. In the block where it is located, its outer partition screen,
a first inclined surface adjacent to the tread surface; and a second inclined surface adjacent to the tread bottom;
The relative relationship between the inclination angle α_1 with respect to the tread surface normal and the inclination angle α_2 of the second inclined surface with respect to the tread surface normal is 3α_2>α_1>1.5α_2 under 30°>α_2>10°. At the same time, the intersection line A_1 of the first inclined surface with the tread surface, the intersection line A_2 of the virtual extension surface of the second inclined surface with the tread surface, and the line of intersection between the inner partition surface of the block and the tread surface. Between intersection line B, tread surface length between A_2 and B x 0.4<A_1 to B
A two-wheeled vehicle tire for rough terrain, characterized in that the tread surface length between A_2 and B×0.7.