JPH0325005A - Pneumatic tire pair for two-wheeled vehicle - Google Patents

Abstract

PURPOSE:To improve balance of performance during high speed running by giving transverse stiffness to a front tire and grip performance to a rear tire through making a carcass ply so as to be a duplex layer by means of side walls, and further by specifying arrange angles of carcass ply cords and belt cords of the front and rear tires. CONSTITUTION:Carcass plies 12a and 12b of a front tire are made of organic fiber cords arranged in the same direction with respect to the equatorial plane of the tire in the range from 40 to 70 deg.. A belt 18 having organic fiber codes arranged in the same direction with respect to the equatorial plane in the range from 0 to 30 deg. are arranged between a tread 14 and a carcass 12. As for the rear tire, organic fiber codes of carcass plies 22a and 22b are arranged in the direction from 75 to 90 deg. with respect to the equatorial plane, and cords of a belt 28 are arranged almost in parallel to the equatorial plane. By this constitution, performance necessary for the front and rear tires can be satisfied and balance of performance during high speed running can be improved.

Description

Detailed Description of the Invention (Field of Industrial Application) This invention relates to a pneumatic tire for a two-wheeled vehicle, which is attached to the front and rear wheels of a two-wheeled vehicle, respectively, and which balances steering stability at high speeds. This invention relates to a pair of pneumatic tires for use.

(Prior art) A cord with a large elastic modulus, for example, a high modulus polyester, A radial tire for two-wheeled vehicles has a belt made of cords made of Rayon or aromatic polyamide fibers spirally wound in the width direction of the tire, due to the so-called "hoop" effect of the spirally wound belt. ,
Even when driving at high speeds, there is little protrusion of the tire outward in the radial direction, and the movement of the tread rubber is small, so compared to bias tires, heat generation and rolling resistance are low, and the tires have excellent wear resistance. It has many features such as less reduction in ground contact area and is lightweight.

On the other hand, the cords of the carcass ply are arranged in one direction at an angle range of 20° to 40° with respect to the tire equatorial plane, and
Bias tires for motorcycles, which have cords arranged in one direction across the cords, have a structure that allows the sidewall rigidity to be set almost uniformly and higher than that of radial tires, so they are smoother. It has the advantage of being able to generate a strong camber thrust.

(Problem to be Solved by the Invention) However, in a radial tire for a two-wheeled vehicle, the extending direction of the cord constituting the belt disposed outside the carcass is
Since the direction is approximately equal to the equatorial plane of the tire, it can function satisfactorily when the vehicle is running straight, but it has been difficult to ensure sufficient rigidity to resist lateral forces.

On the other hand, bias tires have poor wear resistance and high-speed running performance due to the movement of the tread rubber, heat generation, and large rolling resistance, and furthermore, they have increased weight.
The problem had not been resolved.

The present invention was made in view of these problems, and provides a pneumatic tire for two-wheeled vehicles that satisfies the respective performances required for the front and rear wheels of a two-wheeled vehicle and improves performance at high speeds in a well-balanced manner. Its purpose is to provide a

(Means for Achieving the Object) In order to achieve this object, in the present invention, a pair of sidewalls and a tread are connected in a toroidal manner, and each of these parts is set at a predetermined angle with respect to the equatorial plane of the tire. The tire is reinforced with a carcass consisting of organic fiber cords arranged in the - direction within the range, and both ends of at least one layer of Kerr force sply are wrapped around bead wires embedded in the radially inner ends of both sidewalls. In a pneumatic tire for two-wheeled vehicles, the carcass ply of the front wheel tire comprises at least one belt made of a cord wound outward in the direction of the rotational axis and spirally wound around the outer periphery of the carcass and extending in the width direction of the tire. , the cords forming at least two layers on the sidewall and forming the carcass bridle are arranged in one direction within an angle range of 40° to 70' with respect to the tire equatorial plane, and the cords of the front tire belt are connected to the tire. The cords constituting the carcass ply of the rear tire are arranged in one direction within an angle range of 0° to 30° with respect to the equatorial plane, while the cords forming the carcass ply of the rear tire are arranged at an angle of 75' to 90° with respect to the tire's equatorial plane. The cords of the rear tire belt are arranged in one direction within the range, and the cords of the rear tire belt are arranged approximately parallel to the tire equatorial plane.

(Function) Therefore, in such a tire pair, the front tire is provided with sufficient lateral rigidity, while the rear tire is provided with excellent grip performance, and in addition, the front and rear tires are provided with sufficient lateral rigidity. Since both tires are significantly prevented from "protruding" outward in the radial direction, handling stability at high speeds can be improved.

(Embodiments) Hereinafter, preferred embodiments of a pair of pneumatic tires for two-wheeled vehicles according to the present invention will be described in detail with reference to the drawings.

FIGS. 1(a) and 0)) are views respectively showing the front and rear wheels of a tire pair according to a preferred embodiment of the present invention. , 20, both ends of the carcass bries 12a, 12b and 22a, 22b, which constitute the carcass l2 and 22 of each tire, and which are two pieces -m in this embodiment, are connected from the inner side to the outer side. Roll up towards.

In the front tire shown in FIG. 1(a), the braises 12a and 12b constituting the carcass 12 are arranged in one direction at an angle range of 40'' to 70'' with respect to the equatorial plane of the tire. organic fiber cord, for example, thickness 840d/2
66 nylon cords are arranged so as to cross each other diagonally.

The tread 14, which can have a circumferential main groove formed on its surface mainly for the purpose of improving the drainage performance of the tire, is connected to the sidewall 16 in a toroidal manner, and is connected between the tread 16 and the car forceps 12. The . For example, a belt 18 made of a 66 nylon cord with a length L890d/2 is provided.

Here, the angle between the cords of the mutually oblique carcass brises 1.2a and 12b constituting the carcass I2 with respect to the tire equatorial plane is within the angle range of 40'' to 70°. If the angle is less than 40°,
(This is because it is not possible to maintain the desired tire shape when applying pressurized fluid inside the tire. On the other hand, if the angle exceeds 70°, the lateral rigidity of the carcass may not be sufficient. (This is because it becomes difficult to maintain a constant performance as a front tire, especially the rate of increase in camber thrust with respect to the camber angle.) Furthermore, the belt 18 of the front tire shown in FIG. The reason why the angle that the cord makes with the tire equatorial plane is selected from within the range of 0° to 30° is because if the angle exceeds 30°, the tire will protrude outward in the radial direction during high-speed driving. This is because tires cannot be sufficiently restrained and therefore cannot provide the intended high-speed running performance.By adopting this structure, a simpler and lighter structure can be achieved compared to conventional tires. It is possible to provide a front tire with excellent responsiveness.

In addition, when the angle between the cord of the belt 18 and the tire equatorial plane is substantially 0°, the belt 18 can be shaped by winding the cord in a spiral around the outer circumference of the carcass. In that case, it is possible to prevent tire protrusion more efficiently than when the cords are arranged at an angle to the tire equatorial plane.

Of course, the method is not limited to this, and as in the case where the cord makes a certain angle with respect to the tire equatorial plane,
It is also possible to make a belt by placing fabric cut in advance at a certain angle of 30' or less on the outside of the carcass. In addition to the function of preventing the tire from expanding outward in the radial direction, the belt cord also functions to cooperate with the carcass braai and contribute to improving the rigidity of the tire casing. Since the tire is constructed so that the carcass forms at least two layers on the sidewall, sufficient casing rigidity is imparted to the front tire.

In this embodiment, by extending the rolled up end of the carcass bly 12a in the direction of the end of the tread l4, the carcass bly 12a, 1
2b and the rolled up part of the carcass braai 12a, but it is of course possible to make the rolled up end of the carcass brai into a layer and the rolled up part of the carcass. It is also possible to have two or more layers of carcass brazing without having to extend it to the tread end side.

On the other hand, in the rear tire according to the present embodiment shown in FIG. 1(b), the braai constituting the carcass 22 is made of two layers, and each ply 22a. The cords 22b are arranged so as to be oblique to each other within an angle range of 75° to 90° with respect to the tire equatorial plane. In addition, in this example, the car force sublying layer is made of two layers, but it is not necessarily necessary to make it a plurality of layers of two or more layers, and it is also possible to make it a single layer according to the performance required of the tire. Therefore, it is possible to make the tire weight lighter.

For example, the cords of each carcass ply arranged in one direction and intersecting each other have a thickness of 1260 d/2.
66 nylon can be used, and the angle that these cords make with the tire's equatorial plane is 75° to 90°.If the angle is smaller than 75°, the rigidity of the sidewall becomes large and it becomes difficult to handle uneven road surfaces. This is because straight-line stability and grip performance deteriorate.

Further, a belt 28 made of cords arranged in one direction substantially parallel to the tire equatorial plane is disposed between the carcass 22 and the tread 24. Here, in order to ensure good wet performance of the tire, it is of course possible to form grooves in the same direction or inclined grooves in the tread 24 which is connected to the sidewall 26 in a toroidal manner. is omitted for brevity.

As in the case of the front tire, the belt 28 is made of cords arranged in one direction almost parallel to the tire equatorial plane.
By spirally winding the cord outside the carcass 22 and extending it in the width direction of the tire, it can be easily shaped. The cord material can be chosen from fibers with a high modulus of elasticity, such as high modulus polyester, rayon, high tenacity polyvinyl alcohol fibers, or aromatic polyamide fibers; Rate is 600 kg/m
The hoop effect of the belt 28, which is wound with a cord larger than an inch, can efficiently prevent the tread from expanding outward during high-speed running.The movement of the tread rubber is suppressed. In addition to minimizing heat generation, rolling resistance, and reduction in ground contact area, the cords of the carcass ply are arranged substantially in the radial direction of the tire, allowing the sidewall to have a flexible structure, which improves performance. This means that grip performance can be obtained.

[Comparative example]

Comparative tests regarding straight-line stability, turning stability, responsiveness, and collapse between a tire pair of the present invention and a conventional radial tire pair will be described below.

◎Tire specifications/Tire size: Front wheel: CR120/70R 17 Rear wheel: MCR170/60R 17 ・Carcass: Front wheel: Thickness 840d/2 66 nylon Rear wheel: Thickness 12
60d/2 66 nylon belt: Front wheel: Thickness 1890d/2 66 nylon Rear wheel: Thickness 1
500d/2 Kevlar (product name) ◇ Rear tire: A single layer of carcass ply is arranged so that its cord makes a 90° angle to the tire's equator, and a single layer of belt is arranged so that its cord makes a 90° angle to the tire's equator. It was placed almost parallel to the surface.

◇Front tire: Invention: Two layers of carcass ply, each The cord of the ply is against the equatorial plane. to each other so as to form a 60' angle. diagonally, Even more help with that code is at an angle of 20' with respect to the equatorial plane. They were placed diagonally across each other.

Invention 2: Two layers of carcass plies are arranged obliquely to each other so that the cords of each ply form an angle of 60 degrees to the equatorial plane, and a two-layer belt is arranged such that each cord of each ply makes an angle of 20 degrees to the equatorial plane. They were placed diagonally across each other to form an angle.

Comparative Example 1: One layer of carcass ply arranged with its cords at an angle of 90″ to the equatorial plane, and one layer of belt arranged so its cords are approximately parallel to the equatorial plane. did.

Comparative Example 2: Two layers of Kerr force belts are arranged so that the cords of each belt make an angle of 90° with respect to the equatorial plane, and one layer of belt is arranged so that the cords of each belt make an angle of approximately 90° with respect to the equatorial plane. Arranged so that they are parallel.

◎Test method A feeling test was conducted by alternately mounting the invention tire for the front wheel and the comparison tire on a motorcycle equipped with the tire for the rear wheel described above.The performance of each was evaluated by indexing, and the results are shown in the table below. Shown below. Note that the larger the index, the better the performance.

As is clear from the above table, according to the tire pair of the present invention,
The cord that makes up the carcass bridle of the front wheel tire is set at 60 degrees with respect to the tire's equator plane, and the angle of the cord of the belt located outside of the cord with respect to the tire's equator plane is set at 20''. The cords that make up the carcass ply are set at 90 degrees with respect to the tire's equator plane, and the cord of bell 1 located outside of the cord is arranged approximately parallel to the tire's equator plane. It is possible to improve the response performance and slump feeling of the tire without substantially impairing stability.

(Effects of the Invention) Thus, according to the present invention, a pair of pneumatic tires for a two-wheeled vehicle is provided that satisfies the respective performances required for the front and rear wheels of a two-wheeled vehicle and has improved performance in a well-balanced manner during high-speed running. be able to.

[Brief explanation of drawings]

FIG. 1(a) is a sectional view schematically showing a front tire according to the motorcycle tire pair of the present invention, and FIG. 1(b) is
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing a rear tire according to a pair of tires for a two-wheeled vehicle according to the present invention. 10.20...Bead wire 12.22-One carcass 12a, 12b, 22a, 22b-One carcass ply 14.24-Tread 16.16...-Side wall 18.28...-Belt

Claims (1)

[Claims] 1. A pair of sidewalls and a tread are connected in a toroidal manner, and each part is made of a ply in which organic fiber cords are arranged in one direction within a predetermined angle range with respect to the equatorial plane of the tire. The carcass is reinforced, and both ends of at least one layer of the carcass ply are wound outward in the rotational axis direction of the tire around bead wires embedded in the radially inner ends of both sidewalls, and the carcass plies are rolled up toward the outside in the rotational axis direction of the tire. In a pneumatic motorcycle tire, in which at least one layer of belt with cords arranged in one direction within an angular range is disposed outside the carcass, the carcass ply of the front tire has at least two layers on the sidewall, and the carcass ply has at least two layers on the sidewall. The cords constituting the ply are arranged in one direction within an angle range of 40° to 70° with respect to the tire equatorial plane, and the cords of the front tire belt are arranged at an angle of 0° to 30° with respect to the tire equatorial plane. The cords constituting the carcass ply of the rear tire are arranged in one direction within an angular range of 75° to 90° relative to the tire's equatorial plane, and A pair of pneumatic tires for two-wheeled vehicles, characterized in that the cord of the belt of the tire is arranged substantially parallel to the tire's equator plane.