JPH01145203A - Radial tyre - Google Patents

Abstract

PURPOSE:To efficiently prevent a cap layer from separating from tyre rubber so as to enhance high speed durability by providing the cap layer using at least one layer cord ply of rubber coated carbon fiber in parallel. CONSTITUTION:A carcass 3 whose both ends are turned up from the inside of a tyre to the outside around a pair of right and left bead cores 2 so as to be linked, a belt layer 4 which is arranged radially outside the carcass 3 and a cap layer 5 which is arranged radially outside the belt layer 4 are respectively provided in a radial tyre. The carcass 3 is formed with an outer layer 3A which surrounds the bead core 2 through a reinforcing layer 9 and an inner layer 3B arranged along the inside surface of the outer layer 3A. Also, the belt layer 4 is formed by means of putting together cord plys 4A, 4B of inner and outer layers made of steel cord or the like. Further, the cap layer 5 is formed with a cord ply 5A which is made by means of parallel weaving rubber coated carbon fiber cords with crosslink thread.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radial tire with improved high-speed durability.

[Background technology]

In recent years, as automobiles have become faster, there has been a strong demand for tires to have improved high-speed durability.

In addition, in order to satisfy such requirements, conventionally, in the case of radial tires, a cap layer consisting of a cord ply in which nylon cords are arranged parallel to the circumferential direction of the tire is placed outside the belt layer, and the circumference of the belt layer is By improving the directional rigidity and suppressing belt cord breakage, it was possible to improve handling stability and durability during high-speed running.

[Problem that the invention seeks to solve]

However, such nylon cords have poor tensile strength and high elongation, and therefore tend to cause lifting of the cords due to centrifugal force that accompanies tire rotation during high-speed running. Particularly at the shoulders at both ends of the cord, where the tension is reduced during tire molding, lifting of the cord causes significant separation from the surrounding rubber, reducing the high-speed durability of the tire.

In view of this situation, the present invention is based on the use of a carbon fiber cord with excellent tensile strength and low elongation for the cap layer, which prevents lifting of the cap layer and improves the high-speed durability of the tire. The aim is to provide a radial tire that can be significantly improved.

[Means for solving problems]

The present invention comprises a toroidal carcass that is wound around a pair of left and right bead cores and locked at both ends, and a belt layer that is made of a cord ply in which belt cords are arranged in parallel and that is arranged on the outside in the radial direction of the carcass. While providing
The present invention is a radial tire in which a cap layer using at least one cord ply made of rubberized carbon fiber cords arranged in parallel is provided on the outside of the belt layer in the radial direction.

An embodiment of the present invention will be described below based on the drawings.

In FIG. 1, the radial tire 1 of the present invention includes a carcass 3 that is folded back and locked from the inside of the tire to the outside around a pair of left and right bead cores 2, and a belt layer 4 that is disposed on the outside of the carcass 3 in the radial direction. A cap layer 5 is provided on the radially outer side of the belt layer 4.

The carcass 3 includes an outer layer 3A surrounding the bead core 2 via a reinforcing layer 9, and an inner layer 3A arranged along the inner surface of the outer layer 3A.
13B, the folded end 3A1 of the outer Jif3A is interrupted above the bead core 2, and the inner Jif3
The folded end 3B1 of B is interrupted near the maximum middle position of the tire. The reinforcement N9 prevents friction between the bead core 2 and the tire 3A, which moves as the tire deforms due to contact with the ground, and increases the rigidity of the bead portion.Bead apex 10 is provided between the reinforcements N9 to increase lateral rigidity. It's improving. Further, the bead portion 7 is provided with a chafer 11 for preventing rim displacement. Naori-cass 3 has a radial structure in which the carcass cords are arranged at 60 to 901 points with respect to the tire equator, and as the carcass cords, organic fiber cords such as nylon, rayon, polyester, etc. can be used in addition to steel cords. Can be done.

In this example, the belt 714 is made of a stacked body of the inner and outer cord plies 4A and 4B, and the inner cord ply 4
By making the width W4A of A about 1.01 to 1.20 times wider than the width W4B of the outer cord ply 4B, the concentration of the rigidity difference between the edges a and b and the surrounding rubber due to the coincidence of each edge a and b is avoided. Preventing it from occurring.

The cord plies 4A and 4B are belt cords, which are steel cords in this example, and are arranged at a distance of 10 to 30 mm with respect to the tire equator.
The inner and outer cord plies 4A and 4B are arranged parallel to each other with an inclination of about .degree., and have a cross-ply structure in which the inner and outer cord plies 4A and 4B intersect with each other, thereby improving the uniformity of the tire.

Note that the outer cord ply 4B can also be made wider than the inner cord ply 4A.

In addition to the above-mentioned steel cords, polyester cords, nylon cords, aramid cords, and carbon fiber cords can be suitably used as belt cords, and the belt layer 4 may use a mixture of cord plies made of different belt cord materials.

In this example, the cap layer 5 is made of a cord ply 5A, which is a sash-like woven fabric in which parallel rubberized carbon fiber cords are woven by weft, and the cords are arranged at an angle of θ to 5@ with respect to the tire equator and at the ends thereof. Edge C is attached to the belt layer 4
It is arranged on the radially outer side of the belt layer 4 beyond the edge edges a and b of the belt layer 4 .

Note that the cord ply 5A can also be formed as a multi-thread winding body in which a rubberized carbon fiber cord is spirally wound on the belt layer 4 along the circumferential direction of the tire, and in such a case, the cord ply 5A can be It has an endless shape and enables uniform reinforcement along the circumferential direction of the tire.

Note that charcoal fiber cord is a cord formed from fiber filaments obtained by high-temperature firing of viscose rayon, polyacrylonitrile fibers, or pitch-melt-spun fibers, and graphite fiber filaments obtained by further high-temperature treatment of these fibers. Yes, for example trading cards (product name)
As shown in Table 1, it has greater tensile strength and lower elongation than conventional nylon cords (nylon 6 and nylon 66).

Therefore, the cap layer 5 can increase the circumferential rigidity of the belt layer 4, reduce the elongation of the cord caused by centrifugal force, and prevent lifting of the belt layer over its entire surface, thereby improving high-speed handling stability and high-speed durability of the tire. Greatly improved. In addition, since the cap layer 5 is rubberized in advance on the cord, it is possible to prevent poor adhesion with the tire rubber.
Rubber peeling during running can be further reduced.

〔Example〕

A tire with a tire size of 185/70R14 was prototyped according to the specifications shown in Tables 2 and 3. Also, they meet the standard ECE30
Table 3 shows the results of a high-speed durability test using indexes to evaluate the handling stability, wear resistance, and riding comfort that appear at high speeds.

Note that the index is 100 for the conventional tire, and the larger the index is, the better the tire is. All of the tested products showed better results than the conventional tire and the comparative product.

〔Effect of the invention〕

As mentioned above, the radial tire of the present invention is provided with a cap layer using at least one cord ply made of rubberized carbon fiber cords arranged in parallel, so that separation from the tire rubber by lifting of the belt layer is effective. This greatly improves durability at high speeds.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention. 2-・Bead core, 3・-・-carcass, 4-・
- Belt layer, 4A, 4B... Cord ply, 5
... Cap layer, 5A-... Cord ply.

Claims (4)

[Claims] (1) A toroidal carcass that is wound around a pair of left and right bead cores and locked at both ends, and a belt layer that is made of a cord ply in which belt cords are arranged in parallel and is arranged on the outside in the radial direction of the carcass. and a cap layer using at least one cord ply made of rubberized carbon fiber cords arranged in parallel, provided on the radial outer side of the belt layer. (2) Claim 1, wherein the belt cord is a steel cord, a polyester cord, a nylon cord, an aramid cord, or a carbon fiber cord.
Radial tires listed in section. (3) The cap layer is formed by weaving carbon fiber cords in a blind shape to form a cord ply in which the carbon fiber cords are arranged in parallel. tire. (4) The cap layer is characterized by forming a cord ply in which the carbon fiber cords are arranged in parallel by spirally winding the carbon fiber cords in the tire circumferential direction. Radial tires listed in section.