JP3052165B2 - Pneumatic radial tire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic radial tire having a high degree of uniformity without a stepped splice portion in a belt cover layer.

[0002]

2. Description of the Related Art A pneumatic radial tire in which a belt layer is formed of a steel cord exhibits excellent steering stability due to the high elasticity of the steel cord. However, on the other hand, since the steel cord has a very large mass, the belt layer rises to both ends due to centrifugal force during high-speed running, and separation with the rubber layer is easily generated, so high-speed durability is reduced. There is a problem. For this reason, in a high-speed pneumatic radial tire, at least both ends of the belt layer are covered with a belt cover layer made of nylon cord or the like so that the cord angle is substantially 0 ° with respect to the tire circumferential direction. .

Conventionally, as a method of forming the above-mentioned belt cover layer, a belt-shaped rubberized sheet is wound around its reinforcing cord so as to be substantially at 0 ° to the tire circumferential direction.
One is formed by wrapping and splicing both ends, and the other is formed by winding one reinforcing cord spirally endlessly at a minute cord angle close to 0 ° with respect to the tire circumferential direction. is there. In the former, the splice part forms a projecting step,
It was inevitable that it would reduce the uniformity of the tire.

On the other hand, since the latter does not form a step-like splice, the uniformity of the tire is greatly improved, and it can be said that the tire is superior to the former. However, since this belt cover layer must be formed by winding one reinforcing cord continuously until a constant belt width is obtained at the time of tire production, it takes a very long time, and there is a disadvantage that productivity is extremely low. . In particular, when the belt cover layer is configured by combining a plurality of types of reinforcing cords, it is inevitable that the productivity is further reduced.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic radial tire which can be manufactured with high productivity while having a uniformity equal to or higher than that of an endless winding belt cover layer.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a carcass layer in which both ends are engaged with bead cores at both left and right ends via a tread portion and left and right side wall portions, respectively. In a pneumatic radial tire in which a belt layer made of a steel cord is arranged around the outer periphery of the tread portion of the tire layer in the tire circumferential direction, and at least both shoulder portions of the belt layer are covered by a belt cover layer, the belt cover layer is formed by a cylinder. This tubular fabric is arranged in a plurality of rows in parallel while winding at least one reinforcing cord endlessly in the tire circumferential direction, and the reinforcing cords arranged in the plurality of rows are arranged in the tire circumferential direction. It is characterized in that weft yarns are woven in several places.

[0007] Since the belt cover layer is formed by using the tubular fabric in which at least one reinforcing cord is endlessly wound, a uniform splice portion is not formed in the tire circumferential direction, and the uniformity is reduced. Can be improved. In addition, since the reinforcing cords are restrained at regular intervals by the weft yarns, the cord density of the belt cover layer can be kept uniform, and higher uniformity can be achieved. In addition, the use of a tubular fabric woven in advance simplifies the formation of the belt cover layer and enables efficient production.

In addition, since a plurality of types of reinforcing cords can be spliced at a constant width in the same woven fabric, even when a belt cover layer is composed of a plurality of types of reinforcing cords, the tubular woven fabric has a plurality of layers. A simple structure that does not extend can be provided.

[0009]

1 and 2 show meridional sections of a pneumatic radial tire according to an embodiment of the present invention, respectively.
In these figures, 1 is a tread portion, and 2 is a sidewall portion. The carcass layer 4 is provided inside the tire over the tread portion 1 and the left and right sidewall portions 2, and both ends are wound around the left and right bead cores 3 from the inside of the tire to the outside. On the outer periphery of the carcass layer 4 corresponding to the tread portion 1, two belt layers 5 made of a steel cord are arranged. The steel cords of the belt layer 5 form a cord angle of 10 to 35 ° with respect to the tire circumferential direction, and have a relationship of intersecting each other between the layers.

Further, a belt cover layer 7 made of reinforcing cords 7a arranged at substantially 0 ° with respect to the tire circumferential direction is provided on the outer periphery of the belt layer 5 so as to cover the belt layer 5 by centrifugal force during high-speed running. So that the ends do not rise. The belt cover layer 7 only needs to cover at least both end portions of the belt layer 5, and in the case of the tire of FIG. 1, only covers both end portions of the belt layer 5, and in the case of the tire of FIG. The entire width of the belt layer 5 is covered. Furthermore, in the case of super high-speed tires,
In some cases, both configurations of the belt cover layer of FIG. 1 and the belt cover layer of FIG. 2 may be combined.

In the present invention, the belt cover layer 7
Is constituted by using a tubular fabric 70 as shown in FIG. 3 as a raw material. The tubular woven fabric 70 has at least one reinforcing cord 7a preliminarily treated with an adhesive or coated with rubber, and is arranged endlessly at a constant interval in a spiral shape in the circumferential direction. A plurality of adhesive-treated weft yarns 8 arranged at regular intervals in the direction are woven in the longitudinal direction (axial direction). The tubular fabric 70 of the raw material is cut so as to have a predetermined width W required as the belt cover layer 7, and is mounted so as to cover both ends or the entire width of the belt layer 5.

The pneumatic radial tire according to the present invention comprises:
Since the belt cover layer 7 is formed by using the tubular fabric 70 woven in advance in this manner, the formation of the belt cover layer at the time of manufacturing the tire is simplified, and the reinforcing cord 1 is formed.
The productivity is improved as compared with the case where the book is formed by endless winding. Further, since the belt cover layer 7 does not form a step-like splice in the tire circumferential direction, uniformity is improved. Moreover, since the reinforcing cords 7a are constrained by the wefts 8 at a fixed cord interval, disturbance is hardly generated by disturbance, and a uniform cord density is always maintained, whereby uniformity can be further improved.

In the present invention, the belt cover layer 7 composed of the tubular woven fabric 70 is provided with one kind of reinforcing cord 7a.
Or two or more types of reinforcing cords. For example, as shown in FIG. 2, in the belt cover layer 7 which covers the entire width of the belt layer 5, the reinforcing cord in the portion covering the central part of the belt layer 5 is a relatively small denier cord, The reinforcing cord in the portion covering the belt part may be a cord with a large denier, or the reinforcing cord in the central part of the belt layer 5 may be a nylon cord, while the reinforcing cords at both ends may be made of an aramid cord, a steel cord or the like. This is the case for the strength code. By weaving such a combination of two or more types of reinforcing cords into a single tubular woven fabric, the structure is simple and lightweight, but equivalent to the case where a plurality of belt cover layers with different reinforcing cords are used. High-speed durability can be obtained.

In the present invention, the weaving structure of the tubular fabric used includes plain weave, twill weave, satin weave, and the like. The reinforcing cords constituting the tubular fabric include nylon and polyester used in the conventional belt cover layer. Not only textile cords such as Aramid, but also steel cords composed of extra fine wires can be used. Further, since the weft does not need the strength of the weft used in the conventional tire blind fabric, for example, fine denier drawn yarn such as nylon or polyester, undrawn yarn, or composite yarn, natural fiber, or synthetic fiber can be used. A spun yarn or the like may be used.

[0015]

As described above, in the pneumatic radial tire of the present invention, the belt cover layer is made of a tubular woven fabric in which at least one reinforcing cord is endlessly wound.
A highly uniform tire having no stepped splice can be provided. Further, since the reinforcing cords are restrained at regular intervals by the weft yarns, the cords are less likely to be disturbed by disturbances, and the cord density of the belt cover layer is kept uniform, so that a higher uniformity is possible. In addition, at the time of production, it is only necessary to attach a tubular woven fabric that has been woven in advance, thereby enabling efficient production.

In addition, since a plurality of types of reinforcing cords can be spliced at a predetermined width in the same woven fabric, even when a belt cover layer is formed from a plurality of types of reinforcing cords, the tubular woven fabric has a plurality of layers. A simple and lightweight structure that does not extend can be achieved.

[Brief description of the drawings]

FIG. 1 is a meridional section view showing an embodiment of the present invention.

FIG. 2 is a diagram in which a region where a belt cover layer of FIG. 1 is arranged is changed.

FIG. 3 is a perspective view of a belt cover layer used for the pneumatic tire of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead core 4 Carcass layer 5 Belt layer 7 Belt cover layer 7a Reinforcement cord 8 Weft 40 Cylindrical fabric

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60C 9/18-9/22

Claims (1)

(57) [Claims] 1. A carcass layer in which both ends are respectively engaged with bead cores on both left and right sides from a tread portion via left and right side wall portions, and a steel cord is provided around the outer periphery of the tread portion of the carcass layer in the tire circumferential direction. In a pneumatic radial tire in which at least both shoulder portions of the belt layer are covered with a belt cover layer, the belt cover layer is formed of a tubular fabric, and at least one tubular fabric is formed. Pneumatic radial, which is arranged in a plurality of rows in parallel while winding the reinforcing cords endlessly in the tire circumferential direction, and wefts are woven at several places in the tire circumferential direction of the reinforcing cords arranged in the plurality of rows. tire.