JP2552401B2 - Motorcycle tires - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in the structure of the tread portion of a pneumatic tire for a motorcycle.

[0002]

2. Description of the Related Art A conventional tread portion of a motorcycle tire has, for example, a pattern as shown in FIG. That is, the groove 21 is formed on the tread portion 2 along the equatorial plane, and the grooves 22 independent of the groove 21 are formed on both sides of the groove 21. θ is 20
It is set to about °. That is, both side portions are close to the lug pattern, but the center portion is formed in the rib pattern type.

[0003]

In the above construction, the rib pattern has a feature that the anti-slip effect in the lateral direction is exhibited, but there is a drawback that the traction performance is insufficient. If a lug pattern is adopted in the center portion to improve the traction performance, block chunking (chip) may occur during high speed running. Therefore, in the high-speed tire, the lug pattern cannot be adopted only in the central portion of the tread portion 2 as described above.

The present invention has been made in order to solve the above-mentioned conventional drawbacks, and adopts a lug pattern in the center portion for improving traction performance and does not cause block chunking in a motorcycle. The purpose is to provide a tire for use.

[0005]

The present invention relates to an on-road tire for a motorcycle, in which a tread extends in an arch shape on both sides in the meridian direction from an equatorial plane, and the tread width becomes the maximum width of the tire. The belt layer cords are arranged on the outside substantially parallel to the equatorial plane of the tire, and the belt layer is formed by jointlessly winding the aromatic polyamide fiber cords, and the tread portion has a lug pattern or a horizontally elongated block in the center thereof. The pattern is configured so that the pattern angle θ with respect to the equator is 45 ° ≦ θ ≦ 75 °.

[0006]

In the above construction, the cord layer formed by winding the aromatic polyamide fiber cord in a jointless manner prevents the tire growth during high speed running and prevents block chunking. Good traction performance is provided by the central lug pattern.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, an on-road tire 1 for a motorcycle has a tread portion 2 and sidewalls 4 extending inward in the tire radial direction from both end portions thereof. The carcass ply 3 is arranged inside, and both ends of the carcass ply 3 are wound around the bead cores 31 embedded in the inner ends of the sidewalls 4 and folded back. This carcass ply 3 has at least 1
70-9 or more organic fiber cords with respect to the tire equator
It is arranged at 0 °.

The tread portion 2 extends in an arch shape on both sides in the meridian direction from the equatorial plane, the tread width B becomes the maximum width of the tire, and the belt layer 30 outside the carcass ply 3 is substantially parallel to the equatorial plane of the tire. Arranged in this belt layer 3
0 is aromatic polyamide fiber low twist (24-2
It is formed by winding a jointless cord of 9T / 10 cm). When the belt layer 30 has such a configuration, the tightening force on the carcass ply 3 can be increased and the elongation can be minimized. Therefore, it is possible to suppress the tire growth during high-speed running and prevent block chunking.

A groove 5 as shown in FIG. 2 is formed on the tread portion 2. The groove 5 includes a central groove 51, a lateral groove 53 continuous to the lateral end and extending to one lateral end of the tread portion 2, a central groove 52 disposed in parallel with the central groove 51, and the central grooves. It is composed of a side groove 54 which connects the side ends of 51 and 52, and such a groove 5 is symmetrically arranged, and the central grooves 51 and 52 of the left and right grooves are alternately arranged to form a center portion. It is formed in a rug pattern. A short independent groove 55 is formed on the side of the side groove 54. And the central groove 5
The inclination angle θ of 1,52 with respect to the equator is set to about 60 °.

FIG. 3 shows another embodiment of the present invention, in which a first groove 61 linearly inclined only in the center portion of the tread portion 2 and a central portion continuous with the groove 61 from the center portion. V-shaped grooves 6 each of which is linearly extended to the end portion at a slant opposite to the above and formed of V-shaped grooves 6 are arranged alternately symmetrically to form a center portion in a lug pattern. The inclination angles θ of the first groove 61 and the second groove 62 with respect to the equator are both about 60.
It is set to °.

FIG. 4 shows still another embodiment of the present invention,
A first groove 71 symmetrically arranged in a V-shape in the center of the tread portion 2 and a second groove 71 extending linearly from the side end portion of the groove 71 to the end portion of the tread portion 2 respectively. A substantially V-shaped groove 7 including the groove 72 is arranged and the center portion is formed in a lug pattern. The inclination angle θ of the first groove 71 with respect to the equator is set to about 70 °.

FIG. 5 shows still another embodiment of the present invention,
A first groove 81 linearly arranged in one direction in the center of the tread portion 2 and linearly extending from both side ends of the groove 81 to the end portions of the tread portion 2 at right angles to the equator. The groove 8 including the second groove 82 is arranged, and the center portion is formed in a lug pattern. The inclination angle θ of the first groove 81 with respect to the equator is set to about 60 °.

When a lug pattern is formed in the central portion of the tread portion 2 and the pattern angle θ with respect to the equator is set in an appropriate range as in each of the above-described embodiments, good traction performance is exhibited and the rug pattern is formed. No block chunking will occur. The same effect can be achieved if the pattern angle θ is within the range of 45 ° ≦ θ ≦ 75 °. When θ is 45 ° or less, the traction performance is deteriorated, and when it is 75 ° or more, there is a drawback that the soil and drainage properties are deteriorated. Instead of the lug pattern, a laterally long block pattern may be adopted at the side end of the tread portion 2.

Table 1 shows the results of performance comparison between the tire having the structure shown in FIG. 2 and the tire having the conventional structure.

[0015]

[Table 1]

In Table 1 above, nylon 2 / 1260d was used as the carcass ply in all cases. The pattern uses the pattern configuration of FIG. 2 or the pattern configuration of FIG. 6, and the ground contact area is shown as a ratio when the conventional product is 100. As is clear from this table, the ground contact area of the product of the present invention is 20% larger than that of the conventional product, the dynamic outer diameter growth is significantly smaller than that of the conventional product, and chunking does not occur as a result of continuous high-speed running. I couldn't see it.

[0017]

As described above, according to the present invention, the cord layer formed by winding the aromatic polyamide fiber cord in a jointless manner suppresses tire growth during high-speed running and blocks block during high-speed running. King is prevented from occurring, and good traction performance is exhibited by the lug pattern formed at the center of the tread portion and having a predetermined angle.

[Brief description of drawings]

FIG. 1 is a cross-sectional view taken along the line AA in FIG. 2 of a tire showing an embodiment of the present invention.

FIG. 2 is a partial plan view showing a pattern of a tread portion.

FIG. 3 is a partial plan view showing another embodiment of the pattern of the tread portion.

FIG. 4 is a partial plan view showing another embodiment of the pattern of the tread portion.

FIG. 5 is a partial plan view showing still another embodiment of the pattern of the tread portion.

FIG. 6 is a partial plan view showing an example of a conventional tread pattern.

[Explanation of symbols]

 1 tire 2 tread portion 3 carcass ply 30 belt layer 5, 6, 7, 8 groove forming a tread pattern

Claims (1)

(57) [Claims] 1. An on-road tire for a motorcycle, wherein a tread extends in an arch shape on both sides in a meridian direction from an equatorial plane, a tread width becomes a tire maximum width, and a cord of a belt layer is outside the carcass ply. Are arranged substantially parallel to the equatorial plane of the, and this belt layer is formed by winding the aromatic polyamide fiber cord jointlessly,
The center of the tread is a lug pattern or a horizontally long block pattern, and the pattern angle θ with respect to the equator is 45 ° ≦ θ ≦
A tire for a motorcycle, which is configured to have an angle of 75 °.