JP2916081B2 - Radial tires for motorcycles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can improve the turning performance,
In particular, the present invention relates to a motorcycle radial tire that can be suitably used for a high-performance motorcycle for racing.

[0002]

2. Description of the Related Art In general, a motorcycle tire has an outer surface in a meridional section in order to keep good contact with a road surface when the motorcycle is inclined with a large bank angle when turning. Has a wide tread that clearly curves.

[0003] Maintaining a constant contact area under all driving conditions, that is, a so-called tire footprint, has become a major issue in improving the driving performance of ordinary vehicles, and in particular, there has been a need for an automatic racing system having a radial structure. For motorcycle tires, suppressing cornering power fluctuations due to large cornering power that demonstrates good turning stability to maximize turning speed under racing conditions maintains grip with the road surface, This is important from the viewpoint of improving high-speed turning performance.

The present invention reinforces the tread portion with a breaker assembly having two breaker plies having breaker cords of aromatic polyamide fibers and an auxiliary breaker ply having a reinforcement of nylon material. Basically, the tread can be given the rigidity necessary to counter the cornering power of a large motorcycle bank during turning, which can improve turning performance and has sufficient flexibility to flatten the tread on the ground contact surface. It is intended to provide a radial tire for a motorcycle having a high grip with a road surface and improving running stability.

[0005]

SUMMARY OF THE INVENTION The present invention provides a camber value C / L of 0.5 in a standard state reinforced between edges (3, 4) by a breaker assembly and filled with a normal internal pressure.
Tread part larger than 0.7 and smaller than 0.7 (2)
And an annular bead core (1) disposed radially inward of the breaker assembly, bridged between a pair of bead portions (10, 11), and each bead portion (10, 11).
A radially arranged carcass (14) having folded portions (15, 16) formed by being turned from the inside in the tire axial direction to the outside around the tires (2, 13), and the tread edges (3, 13).
4) A radial tire (1) for a motorcycle, comprising a sidewall portion (8, 9) joining a bead portion (10, 11), wherein the breaker assembly is made of an aromatic polyamide fiber. Two breaker plies (6, 7) whose cords are inclined in the opposite direction to the tire circumferential direction,
An auxiliary breaker ply comprising reinforcements made of nylon material arranged adjacent to the radial outside of the breaker ply (6, 7) and inclined at an angle of 80 to 90 ° with respect to the tire circumferential direction and arranged in parallel with each other; (5) have a and, before two
The aromatic polyamide fiber of the breaker ply (6, 7)
The breaker cord consists of 16 ° with respect to the tire circumferential direction.
At an angle of ~ 30 °, each ply (7, 6,
5) In the tire axial direction from the radial inner side to the outer side
A radial tire for a motorcycle, characterized in that the width of the tire increases gradually .

The reinforcing member made of a nylon material of the auxiliary breaker ply (5) is 85% in the tire circumferential direction.
It is desirable to incline at an angle of ° to 90 °.

The reinforcing member made of a nylon material of the auxiliary breaker ply (5) is desirably a nylon cord, and the fineness thereof is more preferably 2/94 TEX.

Preferably, the width of the auxiliary breaker ply (5) in the tire axial direction is larger than the width of the two breaker plies (6, 7) in the tire axial direction.

The breaker cords made of aromatic polyamide fibers of the two breaker plies (6, 7) are desirably inclined at an angle of 16 ° to 30 ° with respect to the tire circumferential direction. More preferably, it is inclined at an angle of 25 ° with respect to the tire circumferential direction.

Preferably, the outermost breaker ply (6) in the radial direction is wider than the breaker ply (7) adjacent to the inner side in the radial direction of the breaker ply (6).

Further, each ply (7,
In the cases of (6) and (5), it is desirable that the width in the tire axial direction increases sequentially from the inner side to the outer side in the radial direction.

[0012]

The tread portion has a camber value C / L larger than 0.5 and 0.7 in a standard state filled with a normal internal pressure.
And smaller. Here, the camber value C / L is defined as the ratio of the radial distance C between the tread edge and the equatorial point of the tread surface to the axial distance L between the tread edge and the tire equatorial plane. You. As described above, since the camber value C / L is regulated and the breaker assembly is reinforced between the edges of the tread, the tread surface can maintain a stable ground contact area during turning, and particularly, stable turning during high-speed running. Performance can be improved.

When the camber value C / L is set to 0.5 or less, the tread surface hardly follows the turning with a large bank angle peculiar to the motorcycle, and the turning stability tends to be impaired. In this case, the curvature of the tread surface becomes excessively large, and the straight running performance is reduced.

Further, since the camber value C / L is regulated within the above range, the sidewall portion of the motorcycle radial tire according to the present invention has a structure in which the tire portion extends from the bead portion mounted on the rim on the inclined bead seat to the edge of the tread. A large cornering force during high-speed turning, which extends relatively short outward in the axial direction, prevents deformation of the sidewalls in the tire circumferential direction, and is reinforced by a radially arranged carcass that expands due to internal pressure filling. And imparts an appropriate degree of curvature to the tread portion, maintains a constant contact area, facilitates transmission of force, and improves high-speed turning stability.

The breaker assembly further includes two breaker plies in which a breaker cord made of an aromatic polyamide fiber is inclined in a direction opposite to the circumferential direction of the tire, a breaker ply radially outwardly adjacent to the breaker ply, and And an auxiliary breaker ply including a reinforcing member made of a nylon material arranged in parallel with each other at an angle of 80 ° or more and 90 ° or less with respect to the tire circumferential direction. Since the aromatic polyamide fiber has high tensile strength and tensile elastic modulus, the rigidity of the breaker assembly can sufficiently bear the radial outward force of the tread portion, and the tread portion can withstand a large centrifugal force due to high-speed running. To reduce the lifting of the tire, and to achieve a high level of durability.The breaker assembly also increases the lateral rigidity of the tread and minimizes variations in the ground contact area due to large cornering power during high-speed turning. , Improving high-speed stability, and in particular, turning performance.

An auxiliary breaker ply having a reinforcement made of a nylon material disposed substantially in a radial direction,
Since the two breaker plies are reinforced without excessively increasing the vertical rigidity of the tread portion, the tread portion can be given sufficient flexibility to promote flattening in the contact area, and the grip force can be increased. In addition to providing high running stability, the rigidity of the breaker assembly can be sufficiently reduced while maintaining the lateral rigidity of the tread portion with respect to the radially inward pushing force at the tread portion. The characteristics can be increased and the riding comfort can be improved.

The breaker cord is inclined at an angle of 16 ° or more and 30 ° or less with respect to the tire circumferential direction . This makes it possible to maintain the lateral rigidity of the tread portion at an appropriate value while exhibiting a hoop effect by the triangle structure of the two breaker plies. If the angle is smaller than 16 °, the lateral rigidity of the tread portion becomes too small, and the ground contact area largely fluctuates due to the large cornering power at the time of high-speed turning.
If it is larger than this, the tagging effect will be insufficient, and it will be easy to induce lifting on the tread portion at the time of high-speed running, which will cause deterioration of running stability and durability. Therefore, the angle of inclination of the breaker cord with respect to the tire circumferential direction is 16 ° or more and 30 ° or less, more preferably 25 °.

Further, the reinforcing member made of a nylon material of the auxiliary breaker ply is a nylon cord having a relatively small elastic modulus, and the nylon cord is oriented at an angle of 80 ° or more and 90 ° or less with respect to the tire circumferential direction. This makes it possible to impart appropriate radial flexibility to the tread portion without excessively lowering the rigidity of the tread portion, thereby increasing the grip force on the ground contact surface and improving the turning performance due to the suppression of the variation in the contact surface area. And improve running stability.

When the angle is smaller than 80 °, the lateral rigidity of the entire breaker assembly tends to decrease, and the running stability, particularly the high-speed running stability when turning, becomes large. Therefore, the nylon cord is preferably 80 ° to 90 °, more preferably 85 ° or more and 90 ° with respect to the tire circumferential direction.
Tilt at the following angles.

The fineness of the nylon cord is 2 / 94T.
When EX is used, the effect of maintaining the lateral rigidity of the tread portion can be increased by the auxiliary breaker ply, the variation in the ground contact area due to the cornering power is suppressed, and the appropriate degree of flexibility is given by the orientation of the nylon cord, High-speed turning performance and running stability performance can be enhanced in a well-balanced manner.

The width of the auxiliary breaker ply in the tire axial direction is larger than the width of the two breaker plies in the tire axial direction . Thus, lifting of the breaker ply, particularly lifting at the shoulder portion of the tread portion, can be suppressed by the hoop effect of the auxiliary breaker ply, and the durability during high-speed running can be improved.

Further, by making the outermost breaker ply in the radial direction wider than the breaker ply adjacent to the inner side in the radial direction of the breaker ply, the lifting of the shoulder portion of the tread portion can be suppressed, and the durability can be reduced. It can be further improved. Accordingly, the breaker assembly 2
The breaker ply and auxiliary breaker ply increase in width in the tire axial direction from radially inward to outward
Let it.

As described above, the radial tire for a motorcycle according to the present invention can improve the stability in high-speed running, particularly the high-speed turning performance, by organically and integrally combining the above-described components, and can improve the road surface performance. It is possible to increase the grip force of the vehicle, improve high-speed durability and ride comfort, and can be suitably applied to a high-performance motorcycle for racing.

[0024]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a tire meridional sectional view of a radial tire 1 for a motorcycle having a tire size of 190 / 55R17 for high-speed racing.

Referring to FIG. 1, a radial tire 1 for a motorcycle according to the present invention includes a pair of sidewall portions 8 and 9 terminating at bead portions 10 and 11, respectively.
0 and 11 are reinforced by inextensible annular bead cores 12 and 13. Also, between the bead portions 10 and 11, the folded portions 15 and 16 are formed by being folded from the inside in the tire axial direction to the outside around the bead cores 12 and 13, and the bead portions 10 and 11 are firmly attached to the bead portions 10 and 11. The carcass 14 to be fixed is bridged.

In the present embodiment, the carcass 14 is formed of two carcass plies made of a fabric which is covered with rubber and has a nylon cord with a fineness (unit: TEX) of 2/140 arranged substantially radially. Bead part 10,
In 11, bead apexes 17, 18 made of hard rubber fixed to the bead cores 12, 13 and extending radially outward in a tapered manner are disposed. The number of carcass plies may be one, three or more, in addition to two.

In the present embodiment, the radial tire 1 for a motorcycle has a camber value C / L of 0.6 in a standard state filled with a normal internal pressure and has a tread edge 3, which is reinforced by a breaker assembly. 4 comprising a convex tread portion 2 having the same.

The breaker assembly is 2/165 TEX
Has two breaker plies 6, 7 using a woven fabric of a breaker cord made of an aromatic polyamide fiber of No. 3, ie, aramid fiber (Kevlar: registered trademark).

In the present embodiment, the breaker cords of the breaker plies 6 and 7 are arranged at an angle of 25 ° with respect to the tire circumferential direction so as to be opposite to each other. , Formed narrower than the radially outer breaker ply 6.

An auxiliary breaker ply 5 embeded in rubber and provided with a nylon cord having a fineness of 2/94 TEX is provided directly on the outer side of the two breaker plies 6 and 7 in the radial direction and directly in contact with the outer breaker ply 6. Be placed. The nylon cord of the auxiliary breaker ply 5 is inclined at an angle of about 90 ° with respect to the tire circumferential direction.

As shown in FIG. 1, the auxiliary breaker ply 5 and the breaker plies 6, 7, which form the breaker assembly, gradually increase the width in the tire axial direction from the inner side to the outer side in the radial direction. ing. The outermost auxiliary breaker ply 5 extends substantially to the edges 3, 4 of the tread.

[0032]

As described above, the motorcycle radial tire of the present invention can improve cornering power while maintaining the ground contact area, improve running stability, especially high-speed cornering stability, and provide grip with the road surface. It also helps improve high-speed driving performance under racing conditions.

[Brief description of the drawings]

FIG. 1 is a meridional section of a tire showing one embodiment of the present invention.

[Explanation of symbols]

 2 Tread part 3, 4 Tread edge 5 Auxiliary breaker ply 6, 7 Breaker ply 8, 9 Side wall part 10, 11 Bead part 12, 13 Bead core 14 Carcass 15, 16 Turnback part C / L Camber value

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Michael Jackson Birmingham Bee 26 2 Eldie Dray 32 Wellford Avenue (56) References JP-A-5-24409 (JP, A) JP-A-1- 311901 (JP, A) JP-A-60-53404 (JP, A) JP-A-60-38212 (JP, A) JP-A-60-50005 (JP, A) JP-A-2-128903 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) B60C 9/06-9/08 B60C 9/18-9/20

Claims (5)

(57) [Claims] 1. A camber value C / L of more than 0.5 and less than 0.7 in a standard state reinforced between the edges (3, 4) by a breaker assembly and filled with a normal internal pressure. The tread portion (2) is disposed radially inward of the breaker assembly, is bridged between a pair of bead portions (10, 11), and has an annular bead core (12, 12) of each bead portion (10, 11). 13), the folds (15,
16) a radially arranged carcass (14) forming
A radial tire (1) for a motorcycle, comprising a sidewall portion (8, 9) joining an edge (3, 4) of a tread and a bead portion (10, 11), wherein the breaker assembly comprises: Two breaker plies (6, 7) in which a breaker cord made of an aromatic polyamide fiber is tilted in the opposite direction to the tire circumferential direction, and are arranged adjacent to the breaker plies (6, 7) radially outside. and possess a supplementary breaker ply (5) comprising a reinforcing member made of a nylon material arranged parallel to each other inclined at an angle of 80-90 ° with respect to the tire circumferential direction, two of the breaker ply
Breaker made of aromatic polyamide fiber of (6, 7)
At an angle of 16 ° to 30 ° with respect to the tire circumferential direction.
Tilt and each ply (7,6,5)
A radial tire for a motorcycle, wherein a width in a tire axial direction sequentially increases from a side toward an outside . 2. The reinforcing member made of a nylon material of the auxiliary breaker ply (5) has an angle of 85 ° with respect to the tire circumferential direction.
The radial tire for a motorcycle according to claim 1, wherein the tire is inclined at an angle of 90 °. 3. The motorcycle radial tire according to claim 1, wherein the reinforcing member made of a nylon material of the auxiliary breaker ply (5) is a cord. 4. The radial tire for a motorcycle according to claim 2, wherein the nylon cord of the auxiliary breaker ply (5) is a cord having a fineness of 2/94 TEX. 5. The properties of the two breaker plies (6, 7)
Breaker cords made of aromatic polyamide fibers are used in tires.
The contractor characterized by being inclined at an angle of 25 ° to the circumferential direction.
A radial motor for a motorcycle according to any one of claims 1 to 4.
No.