JP2916080B2 - 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.

[0004] The present invention basically reinforces the tread portion with a breaker assembly having two breaker plies having a breaker cord made of aromatic polyamide fiber and an auxiliary breaker ply having a nylon reinforcement. Rigidity required to counter the cornering power associated with the large bank of the motorcycle at the time of turning can be given to the tread, which can improve turning performance and has enough flexibility to flatten the tread on the ground contact surface, The purpose of the present invention is to provide a radial tire for a motorcycle that can enhance grip with a road surface and improve 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 (5) disposed adjacent and radially inward of the breaker ply (6, 7) and comprising a nylon reinforcement.

Preferably, the nylon reinforcement of the auxiliary breaker ply (5) includes nylon cords arranged in parallel with each other.

[0007] The nylon cord is arranged in the tire circumferential direction.
The inclination angle with respect to the angle is set to 75 ° to 85 °.

[0008] Further, the nylon cord is as described above.
In addition, the auxiliary breaker ply (5) is inclined in the opposite direction to the breaker cord made of aromatic polyamide fiber of the breaker ply (6) adjacent to the breaker ply (6) in the radial direction .

The width of the auxiliary breaker ply (5) in the tire axial direction is smaller than the width of the breaker ply (6) adjacent on the radially outer side of the auxiliary breaker ply (5) in the tire axial direction. It is desirable.

Preferably, the breaker cords of the two breaker plies (6, 7) comprising aromatic polyamide fibers are 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.

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

Each ply (5, 5) of the breaker assembly
In 6 and 7), 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.

[0013]

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 becomes difficult to follow a turn with a large bank angle peculiar to a motorcycle, which tends to impair the turning stability performance. 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 restricted to the above range, the sidewall portion of the motorcycle radial tire of the present invention is mounted on the inclined bead seat from the bead portion mounted on the rim 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 inwardly adjacent to the breaker ply, and And an auxiliary breaker ply having a nylon reinforcement. 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.

[0017] Further, the nylon reinforcement body having the nylon cords arranged in parallel with each other and the two breaker plies make it possible to flatten the tread portion in a region in contact with the tread portion without lowering the lateral rigidity of the tread portion. In addition to being able to provide sufficient flexibility to promote, it can increase grip power and provide excellent running stability, as well as sufficient rigidity of the breaker assembly against radial inward pushing force at the tread portion. Can be reduced, the envelope characteristics can be increased, and riding comfort can be improved.

Preferably, 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. When the angle is smaller than 16 °, the lateral rigidity of the tread portion becomes excessively small, and the ground contact area largely fluctuates due to a large cornering power at the time of high-speed turning. In this case, the tag effect is insufficient, and it becomes easy to induce lifting on the tread portion at the time of high-speed running, which causes 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 °.

[0019] The nylon cord of the auxiliary breaker ply, 75 ° or more and 85 ° or less an angle with respect to the tire circumferential direction, inclined in the opposite direction to the breaker cord adjacent radially outer side of the auxiliary breaker ply ing. Thereby, in the tread portion, the auxiliary breaker ply, together with the two breaker plies, reinforces the carcass like a pantograph, and allows the tread portion to have appropriate radial flexibility without excessively reducing the rigidity of the tread portion. , The gripping force on the ground contact surface can be increased, and the running stability can be improved while being compatible with the improvement of the turning performance accompanying the suppression of the fluctuation of the ground contact area.

[0020] wherein the angle is smaller than 75 °, the lateral rigidity of the entire breaker assembly becomes apt to decrease, running stability, it tends to particularly impair the high-speed running stability during turning increases <br/> ing.

On the other hand, if the angle exceeds 85 °, the breaker
There is a large difference in rigidity between the inside and outside of the assembly,
The tread follows the contact surface in cooperation with the breaker ply
Effect is reduced, leading to reduced grip
is there.

It is desirable that the width of the auxiliary breaker ply in the tire axial direction be smaller than the width of the auxiliary breaker ply in the tire axial direction adjacent to the outer side in the radial direction of the auxiliary breaker ply. Thus, lifting of the auxiliary breaker ply, particularly lifting at the shoulder portion of the tread portion, can be suppressed by the hammer effect of the breaker ply, and 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 on the radially inner side 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 plies and the auxiliary breaker plies preferably have their widths in the tire axial direction sequentially increased from the inner side to the outer side in the radial direction.

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 combining the above-mentioned components organically and integrally, and 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.

[0025]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a tire meridional section of a motorcycle radial tire 1 for high-speed racing having a tire size of 185 / 55R17.

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 having a thickness (unit: TEX) of 2/140 in a substantially radial arrangement. Each 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. Is formed narrower than the radially outer breaker ply 7.

An auxiliary breaker ply 5 is provided radially inward of the two breaker plies 6, 7 in direct contact with the inner breaker ply 6, and is provided with a nylon cord embedded in rubber and having a thickness of 2/140 TEX. Is arranged. The nylon cord of the auxiliary breaker ply 5 is inclined at an angle of 80 ° with respect to the tire circumferential direction, and is oriented in the opposite direction so as to intersect the breaker cord of the adjacent breaker ply 6.

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.

[0033]

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. And increase the durability.

[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 Continuation of the front page (72) Inventor Michael Jackson Birmingham Bee 26 2 Eldie Dray 32 Wellford Avenue (56) References JP-A-60-53404 (JP, A) JP-A-60- 38212 (JP, A) JP-A-60-5005 (JP, A) JP-A-5-24409 (JP, A) JP-A-1-31901 (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 (7)

(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 inclined in the opposite direction to the tire circumferential direction, and are arranged adjacent to the inside of the breaker plies (6, 7) in the radial direction. And auxiliary breaker ply (5) with nylon reinforcement
And the nylon cord of the nylon reinforcement is a tie.
At an angle of 75 ° to 85 ° with respect to the
A radial tire for a motorcycle, characterized in that the tire is inclined in a direction opposite to the breaker cord . 2. The motorcycle radial tire according to claim 1, wherein the nylon reinforcement of the auxiliary breaker ply (5) includes nylon cords arranged in parallel with each other. 3. A tire shaft of said auxiliary breaker ply (5).
The width in the direction is the radial direction of this auxiliary breaker ply (5).
Tire axial direction of the breaker ply (6) adjacent on the outside
The width is smaller than the width of the direction.
The radial tire for a motorcycle according to Claim 1. 4. The properties of the two breaker plies (6, 7)
Breaker cords made of aromatic polyamide fibers are used in tires.
It is characterized by tilting at an angle of 16 ° to 30 ° with respect to the circumferential direction
The motorcycle according to any one of claims 1 to 3,
Giral tire. 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. 6. A radially outermost breaker ply (7).
Are adjacent radially inside the breaker ply (7).
Is wider than the breaker ply (6)
A motorcycle radio according to any one of claims 1 to 5.
Al Tire. 7. Each ply (5, 6,... ) Of said breaker assembly.
7) In the tire axial direction from the radially inner side to the outer side
7. The method as claimed in claim 1, wherein the width of the sheet is gradually increased.
The radial tire for a motorcycle according to any one of the above.