JP2003011614A - Tire for two-wheeler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire for a two-wheeler improving a turning maneuverability and belt durability without damaging various tire performances such as straight traveling performance, high-speed performance, riding comfortableness, and uniformity. SOLUTION: This tire for the two-wheeler is provided with a spiral belt layer formed by parallel disposing cords along a carcass layer arc in the tire width direction. The spiral belt layer is so formed that its single layer is formed in a central area from A to D on the tire cross section including a tire rotary axis, its two-layer structure is formed from both shoulder regions from A to B and from C to D, the belt body is started to be wound from the position A between one belt end B and a tire equator in the direction for separating from the tire equator in order and folded back at the belt end B, then the belt body is wound from the belt end B to the other belt end C and folded back at the belt end C and the belt body is restarted to be wound toward the equator and finished to be wound at the position D between the belt end C and the tire equator in the last.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-wheeled vehicle tire having improved turning and steering performance and belt durability without impairing tire performance such as straight running performance, high speed performance, riding comfort and uniformity.

[0002]

2. Description of the Related Art A so-called spiral, in which a belt-like body having one or a plurality of parallel cords embedded in a coated rubber is spirally wound in a tire rotation axis direction at an angle substantially in the circumferential direction of the tire. If the belt layer is adopted for a two-wheeled vehicle tire, the high-speed durability, straight-line stability, uniformity performance, etc. of the tire can be improved, while the cornering force and the camber at large camber angles, which are important when the vehicle turns. Since the thrust tends to be smaller than that of the conventional cross belt structure, various attempts have been made to improve this point.

For example, there is a tire of the structure described in the examples of EP0756949A. That is, in a pneumatic radial tire for a motorcycle having a belt structure in which reinforcing cords are arranged substantially in the circumferential direction, when the number of cords to be driven near the belt end is made dense in comparison with the center region, when the motorcycle is turning. The lateral rigidity of the car is enhanced, and it is compatible with the shock absorption when traveling straight. However, if the number of cords to be driven in near the belt end portion is made dense, the interface peeling between the rubber at the belt end and the cord is likely to occur, and this portion becomes a core to cause a belt separation failure.

There are also attempts to solve the above problems by adjusting the hardness of the tread rubber. For example, JP-A-4
There is a tire of the construction described in the example of -197805. That is, in a pneumatic radial tire for a motorcycle having a belt structure in which reinforcing cords are arranged substantially in the circumferential direction, a tread structure capable of greatly improving the lateral force at the time of a large camber is divided into three areas. Part of the tread on both sides of the tread is formed into two layers, an inner rubber layer and an outer rubber layer, and the JIS hardness of the inner rubber layer is set to J
Tires have been proposed that are at least 5 degrees larger than the IS hardness.

[0005]

However, when the invention of the above publication is applied to a radial tire having a so-called spiral belt structure to which the present invention is applied, a tread and a belt that are parallel to the ground contact surface at the tire ground contact surface. , Pliers
Rigidity against deformation of bending a tire member in which dust and the like are laminated within the plane (that is, when the tire is subjected to frictional force against the centrifugal force at the ground contact surface, the tire is subjected to such bending deformation within the plane. (It is referred to as bending rigidity) is not sufficiently large, and it is not possible to recover the reduction in steering performance at the time of turning, which is a drawback of the spiral belt structure. Since it is formed in two layers, there is a problem in that the complexity of tire manufacturing is inevitable.

The present invention relates to the steering performance of a two-wheeled vehicle tire having a spiral winding belt structure having a code angle in the circumferential direction, particularly a cornering force and a camber at the time of a large camber.
It is an object of the present invention to provide a two-wheeled vehicle tire in which the turning performance represented by thrust is improved without impairing the performance of other tires.

[0007]

Means for Solving the Problems In order to achieve the above object, the means for solving the present invention are as follows. <1> A belt-shaped body, in which one or a plurality of parallel cords are embedded in a coated rubber, is spirally formed at an outer side of a crown portion of a carcass layer in a tire radial direction at an angle toward a tire equatorial direction. A two-wheeled vehicle tire having a spiral belt layer wound in a tire rotation axis direction and having cords arranged in parallel in a tire width direction along a carcass layer arc, wherein the spiral belt layer is a tire rotation axis. On the tire cross section including, a single layer is formed in the central area (A to D) and a double layer structure is formed in both shoulder areas (A to B and C to D), and one belt end (B) and the tire equator are formed. Starting from a certain position (A) between the belt end (B) and the belt end (B), and then the belt end (B). Wrap up to C), The belt end (C) is folded back and wound again toward the equator, and finally the winding is finished at a position (D) between the belt end (C) and the tire equator. Tires for motorcycles. <2> The two-wheeled vehicle tire according to <1>, wherein the cord embedded in the strip is a steel fiber cord. <3> The motorcycle tire according to <1>, wherein the cord embedded in the belt-shaped body is an organic fiber cord. <4> The cord embedded in the strip is a cord formed by combining steel fibers and organic fibers <1>
A motorcycle tire as described in. <5> The ratio of the area forming the two-layer structure of the spiral belt layer is 15 to 70% of the total area.
The tire for a motorcycle according to any one of 1.

[0008]

The function and effect of the present invention will be described below.
Generally, a so-called spiral belt layer in which a belt-like body in which one or a plurality of parallel cords are embedded in a coated rubber is spirally wound in a tire rotation axis direction at an angle toward the tire equatorial direction. In the belt structure in which the cords are laminated, since the cords are oriented substantially in the tire equatorial direction, the rigidity against expansion in the tire circumferential direction is high, while on the other hand, the rotating shafts in which the cords are arranged in parallel are provided. In the cross section including, the rigidity of the spiral belt layer against bending (in-plane bending rigidity) becomes extremely small. Since the frictional force of the contact surface against the centrifugal force when the motorcycle turns is linked to the amount of in-plane bending rigidity, conventional motorcycle tires with a spiral belt layer are based on the frictional force of the contact surface. Cornering force and camber thrust are reduced.

According to the present invention, in order to improve this drawback of the motorcycle tire having the spiral belt structure, as shown in FIG. 4, both shoulder regions (A to B and C) on the tire cross section including the tire rotation axis. In D to D), the spiral belt layer has a two-layer structure, and in both shoulder regions, the lower spiral belt layer is spirally wound from the equator toward the belt layer end and folded back at the belt end. On the contrary, the upper spiral belt layer is spirally wound from the end of the belt layer toward the tire equator, resulting in a synergistic effect of the upper and lower spiral belt layers intermingling with each other, thereby improving the in-plane bending rigidity. Since it can be set high, the adhesion to the road surface (ability to wrap the unevenness of the road surface) is enhanced, and at the same time, the amount of energy absorbed inside the member against external input is increased and the friction force on the ground contact surface is increased. Generated acts to increase,
The cornering force and the camber thrust of the tires have high values, and the so-called stiffness is strong when the vehicle actually runs, especially when turning.
It is possible to obtain a two-wheeled vehicle tire that exerts a strong grip on the road surface and exerts a strong grip.

Further, as described above, the spiral belt layer of the present invention is folded back at the belt ends (B) and (C) without being cut and is continuous with the upper layer. It is possible to greatly improve the belt durability performance, which can prevent the nucleation of cracks due to the stress concentration near the cutting point of the cord which is often seen at the end portion, which can be prevented.

Incidentally, when the two-wheeled vehicle normally travels straight, it mainly contacts the road surface in the central area of the tire, but in the present invention, as shown in FIG. 4, on the tire cross section including the tire rotation axis. Since the central area (A to D) is composed of only one spiral belt layer, the rigidity against circumferential stretching is high to some extent, but the bending rigidity in the plane is small, and the stability and vibration during straight running or It excels in shock absorption and provides a comfortable ride.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
This will be described in detail with reference to FIGS. The motorcycle tire of the present invention has a pair of bead cores-1 as shown in FIG.
4, a belt-shaped body in which one or a plurality of parallel cords are embedded in a covering rubber is provided in a tire radial direction outer side of a crown portion of a tire carcass layer 12 straddling a toroidal shape, and extends substantially in the tire equator direction. A two-wheeled vehicle tire 10 having a spiral belt layer which is spirally wound in the tire rotation axis direction at an angle and in which cords are arranged in parallel in the tire width direction along a carcass layer arc, The spiral belt layer is one layer in the central area (A to D) on the tire cross section including the tire rotation axis, and is in both shoulder areas (A to B and C).
1 to D) has a two-layer structure, and as shown in FIG. 1, the belt-shaped body is first wound from a position (A) between one belt end (B) and the tire equator (CL), and The belt is wound in the direction away from the equator, folded at the belt end (B), and then wound from the belt end (B) to the other belt end (C) as shown in FIGS. It is configured to be folded back at (C) and wound again toward the equator, and finally to be wound at a position (D) between the belt end (C) and the tire equator, as shown in FIG. It is characterized by that.

In the winding process of the above-mentioned strip, in the area from the position (A) to the belt end (B) and the area from the position (D) to the belt end (C), the lower spiral belt layer is At (B) or at the belt end (C), it is a feature of the present invention that the strip-shaped body, that is, the cord, is not cut but is folded back and is continuous with the upper spiral belt layer.

The cord embedded in the strip in the present invention is not particularly limited and may be appropriately selected according to the two-wheeled vehicle and its usage conditions, but it is important to set the circumferential rigidity particularly high. For use, it is preferable to use a cord made of steel fiber. On the other hand, for motorcycle tires where it is important to reduce the weight of the tire rather than the circumferential rigidity, it is preferable to use a cord made of an organic fiber. In addition, it is preferable to use a cord in which steel fibers and organic fibers are combined (within a band) for a two-wheeled vehicle tire in which both performances are important.

Examples of the steel fiber cords include steel fiber cords usually used for reinforcing tires, belt members and the like. To obtain a particularly high tensile strength, at least 0.7 mass% Of steel, preferably at least 0.8 wt.% Carbon, is desirable.

Examples of the cord made of the organic fiber include organic fiber cords which are usually used for reinforcing tire members such as polyamide fiber, polyester fiber, aramid fiber and rayon fiber. Cords made of group polyamide fibers (trade name "Kevlar"), polyethylene-2,6-naphthalate and high modulus polyester fibers are preferred because of their high tensile modulus.

In the present invention, the ratio of the two-layer structure area of the spiral belt layer to the entire spiral belt layer is preferably 15 to 70%. If the proportion of the two-layer structure area is less than 15%, the in-plane rigidity at the time of turning may be insufficient, while if it exceeds 70%, the vibration or shock absorbing ability at the time of straight running may be reduced. is there.

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples. 10 of FIG. 4 is a meridional sectional view including a tire rotation axis of a motorcycle tire having a spiral belt layer according to the present invention, and the size of the tire is 180 / 55ZR.
Seventeen. The spiral belt layer of the present invention which reinforces the tire carcass layer 12 straddling the pair of bead cores 14 in a toroidal shape has two parallel cords on the tire radial outside of the crown portion of the carcass layer. A belt-like body embedded in the coated rubber is spirally wound in the tire rotation axis direction at an angle toward the tire equatorial direction, and the cords are arranged in parallel in the tire width direction along the carcass arc, and are arranged at the center. The areas (A to D) are arranged in a single layer, and the shoulder areas (A to B and C to D) are arranged in a double layer structure.

The cord in the strip in Example 1 is 15
00d aromatic polyamide fiber (trade name "Kevlar")
The two-strand cord of Example 2 is a 1 × 5 twist cord of 0.21φ steel fiber. In addition, the number of cords to be imbedded in each layer of Example 1 is
Both the central region and both shoulder regions are 32/50 mm, and the number of intra-layer cords of Example 2 is 20/50 mm in both the central region and both shoulder regions.

In the spiral belt layers of the tires of Comparative Examples 1 to 4 shown in FIG. 5, the belt-like body in which two parallel cords are embedded in the covering rubber is the angle which is directed substantially in the tire equator direction. The cords are spirally wound in the tire rotation axis direction, and the cords are arranged in parallel in the tire width direction along the carcass arc, but the central region and both shoulder regions are formed of one layer. It is outside the conditions specified by. Further, the cords of Comparative Examples 1, 2, and 4 use the same keblate cord as that of Example 1, the cord of Comparative Example 3 uses the same steel cord as that of Example 2, and the number of cords to be driven is shown in Table 1. Is filled in.

Next, in order to confirm the effect of improving the performance of the two-wheeled vehicle tire of the present invention, the tires of Examples and Comparative Examples were actually prototyped and the results of a comparative test of durability performance and steering performance will be described. Table 1 shows the evaluation results of each trial tire, which was tested for belt end separation at the time of complete wear and steering performance as a two-wheel vehicle tire at the time of actual vehicle running.

The evaluation method will be described below. <Belt end peeling test at the time of complete abrasion> After mounting the test tire on the regular rim, filling it with an internal pressure of 250 kPa and mounting it on the test motorcycle (rear wheel), and running it on the general road until complete abrasion, The tire was dissected and the length of cracks occurring at the edge of the belt was measured.

<Driving performance test> Four test tires were used.
It is mounted on a 00cc sports type two-wheeled vehicle, and is actually driven on a test course. The 10-point method is used to test the maneuverability, stability, braking, vibration absorption, etc. during straight running and turning. I made a comprehensive evaluation. The results are shown in Table 1 along with the evaluation comments of the test driver.

[0024]

[Table 1]

From the results shown in Table 1, the tires of the examples according to the present invention have good stability and riding comfort in straight running, excellent steering stability in turning, and sufficient belt durability. It was confirmed.

[0026]

EFFECTS OF THE INVENTION In the two-wheeled vehicle tire of the present invention, the drawback of the in-plane rigidity reduction associated with the spiral belt structure of the code angle in the equatorial direction is that stable straight running performance originally expected in the spiral belt structure is obtained. Thus, it is possible to provide a high-performance two-wheeled vehicle tire which is improved in high-speed durability without impairing the steering stability when turning.

[Brief description of drawings]

FIG. 1 is a meridional cross-sectional view sequentially illustrating the structure of a spiral belt layer of a motorcycle tire according to the present invention.

FIG. 2 is a meridional cross-sectional view for sequentially explaining the configuration of the spiral belt layer of the motorcycle tire according to the present invention.

FIG. 3 is a meridional cross-sectional view for sequentially explaining the configuration of the spiral belt layer of the motorcycle tire according to the present invention.

FIG. 4 is a meridional sectional view of a motorcycle tire according to the present invention.

FIG. 5 is a meridian sectional view of a conventional motorcycle tire.

[Explanation of symbols]

10 motorcycle tires 12 carcass layer 14 Bead Core 16 treads

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) B60C 9/18 B60C 9/18 J

Claims (5)

[Claims] 1. A belt-shaped body, in which one or a plurality of parallel cords are embedded in a coated rubber, on the outer side of the crown portion of a carcass layer in the tire radial direction, is spiraled at an angle substantially toward the equatorial direction of the tire. A tire for a two-wheeled vehicle having a spiral belt layer that is wound in the tire rotation axis direction and is arranged in parallel in the tire width direction along the carcass layer arc, wherein the spiral belt layer is a tire. On the tire cross section including the rotation axis, one layer is formed in the central area (A to D) and two layers are formed in both shoulder areas (A to B and C to D), and one belt end (B) is formed. The belt is started to be wound from a position (A) between the tire equator, first wound in the direction away from the tire equator, folded back at the belt end (B), and then from the belt end (B) to the other belt. Wind up to the end (C) It is configured so that it is wrapped around the belt end (C) and wound again toward the equator, and finally ends at a position (D) between the belt end (C) and the tire equator. A characteristic motorcycle tire. 2. The tire for a motorcycle according to claim 1, wherein the cord embedded in the strip is a steel fiber cord. 3. The tire for a motorcycle according to claim 1, wherein the cord embedded in the belt-shaped body is an organic fiber cord. 4. The tire for a motorcycle according to claim 1, wherein the cord embedded in the belt-shaped body is a cord formed by combining steel fiber and organic fiber. 5. The two-wheeled vehicle tire according to claim 1, wherein the ratio of the area having the two-layer structure of the spiral belt layer is 15 to 70% of the total area.