JPH0592498A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To increase a contact boundary area of a bonding part to improve a bonding strength and a structural mechanical strength by a method wherein one or more bent parts in the view from at least one of a tire radial direction and a tire rotating direction are provided in the bonding part of a ring-form tread. CONSTITUTION:A pneumatic tire 1 is molded by winding a band plate-form row tread, which is separately molded, on a laminated carcass ply, and provided with a ring-form tread part 2; a pair of sidewalls 3 extending in a tire radial direction; and a pair of ring-form bead parts 4. The bonding part of the tread 2 wound in a ring from is not formed into a straight line in the view from at least one of a tire radial direction and a tire rotating direction. Namely, it is provided with one or more bent parts 21, 22, 23, 24. In this manner, the contact boundary area of the bonding part is increased to improve a bonding strength and a structural mechanical strength and prevent the release of the surface of the tread 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an annular tread portion,
The present invention relates to a pneumatic tire having a pair of sidewalls and a pair of bead portions.

[0002]

2. Description of the Related Art Generally, a pneumatic tire has an annular tread portion, a pair of sidewalls extending in the tire radial direction from both ends of the tread portion, and a pair of bead portions provided at the sidewall ends and engaging with a rim. It has and.

The method of forming a pneumatic tire is different between a tire having a bias structure and a tire having a radial structure. For example, in the case of a radial tire, on the surface of a flat drum having steps at which the minimum beads can be accommodated is formed at both ends. A method in which a specified number of carcass plies are pasted together, inflated to a state close to the tire size as a finished product using an air bag or mechanical link mechanism, etc., and a separately formed belt plate belt, tread, etc. are wound and pasted together. Is used.

In a conventional pneumatic tire, a separately molded tread (hereinafter referred to as a "rot tread") to be attached to an inflated carcass ply is a tread 200 as shown in FIGS. Is a rectangular shape in plan view and is the longitudinal end of it.
201 and 202 are cut with an inclination in the thickness direction, and when wound on the carcass ply, the inclined surfaces of the joint ends 201 and 202 are aligned and joined to form an annular tread 210 (Fig. 7). reference).

[0005]

However, in the above-mentioned conventional pneumatic tire, the joining portion 203 formed by joining the joining ends 201 and 202 of the rotor tread 200 extends straight in the width direction of the annular tread 210. However, since it is not reinforced structurally, the adhesive strength of this joint 203 will be determined only by the physical properties of the tread rubber, so it is possible to completely suppress the peeling phenomenon that occurs on the tread surface of the tire in use. There was a problem that I could not.

An object of the present invention is to provide a pneumatic tire in which peeling of the tread surface can be suppressed by increasing the strength due to the structure of the joint portion of the tread.

[0007]

A pneumatic tire according to the present invention is formed by winding a separately molded strip tread on a carcass ply that is laminated, and is formed in an annular tread portion and a tire radial direction. In a pneumatic tire including a pair of extending sidewalls and a pair of annular bead portions, a joint portion of a tread that is annularly wound forms a straight line when viewed from at least one of a tire radial direction and a tire rotation axis direction. That is, it has one or a plurality of bent portions, and increases the contact boundary area of the joint portion to improve the adhesive strength and the mechanical strength of the structure, thereby peeling off the tread surface. Can be suppressed.

[0008]

1 is a cross-sectional view in the width direction of a pneumatic tire to which the present invention is applied. The pneumatic tire 1 includes an annular tread 2 and a pair of sidewalls 3 extending from both ends of the annular tread 2 in the tire radial direction. , A pair of bead portions 4 provided at the inner ends of the sidewalls 3 in the radial direction and in which an annular bead core 5 is embedded, and both ends are folded back around the bead core 5 to penetrate both sidewalls 3 and the annular tread 2. A one-ply carcass layer 6 composed of cords arranged in the radial direction of the tire, and a hard rubber having a JISA hardness of 70 to 90 degrees and having a taper shape toward the upper side. The bead apex 7 and the carcass layer 6 are arranged on the outer circumference in the radial direction of the tire, and a plurality of breaker cords formed by twisting steel filaments in parallel with each other. And a breaker layer 8 composed of a plurality of arranged plies.

In FIG. 2, the unfolded rotor tread 20 is formed in the shape of a strip plate, and both ends of the plane shape in the longitudinal direction thereof are joined to join when forming the annular tread 2, When viewed from the thickness direction of the tread 20 (radial direction of the tire when formed into an annular shape), a groove 21 is formed at one joint end, and a protrusion 22 that matches the groove 21 is formed at the other joint end. is doing.

In FIG. 3, the joint ends at both ends in the longitudinal direction of the strip tread 20 are located at one joint end when viewed from the width direction of the tread 20 (the tire width direction when formed into an annular shape). A wedge-shaped concave groove 23 is formed at the joint end of, and a wedge-shaped protrusion 24 that matches the concave groove 23 is formed at the other joint end.
The molding of the tread 20 is performed by heating the strip-shaped tread 20 cut into an appropriate length to a predetermined temperature (for example, about 100 ° C.) and fitting it into a mold.

As shown in FIG. 4, when the rotor tread 20 is wound to form the annular tread 2, the joints formed at both ends in the longitudinal direction of the rotor tread 20 have protrusions in the concave grooves 21.
At the same time when 22 is fitted, the wedge-shaped concave portion 23 is fitted with the wedge-shaped protrusion 24.

According to this structure, the joint portion of the annular tread 2 does not form a straight line when viewed from at least one of the tire radial direction and the tire rotation axis direction, that is, it has one or a plurality of bent portions. Therefore, by increasing the contact boundary area of the joint to improve the adhesive strength and the structural mechanical strength, peeling of the tread surface can be suppressed.

[0013]

Since the present invention is configured as described above, it has the following effects. Since the joint portion of the annular tread has one or a plurality of bent portions as viewed from at least one of the tire radial direction and the tire rotation axis direction, the contact boundary area of the joint portion is increased to increase the adhesive strength. Also, the mechanical strength of the structure is improved, and peeling of the tread surface can be suppressed.

[Brief description of drawings]

FIG. 1 is a widthwise sectional view of a tire to which the present invention has been applied.

FIG. 2 is a plan view of a rotor tread to which the present invention is applied.

FIG. 3 is a side view of a rote tread to which the present invention is applied.

FIG. 4 is a perspective view of an annular tread to which the present invention has been applied.

FIG. 5 is a plan view of a conventional rotor tread.

FIG. 6 is a side view of a conventional rotor tread.

FIG. 7 is a perspective view of a conventional annular tread.

[Explanation of symbols]

 1 tire 2 tread 3 sidewall part 4 bead part 5 bead core 6 carcass layer 7 bead apex 8 breaker layer 9 rubber layer

Claims (1)

[Claims] 1. A pneumatic tire in which a band-plate-shaped tread, which is separately molded on a bonded carcass ply, is wound and molded, wherein a joint portion of the tread formed in an annular shape has a tire radial direction and a tire rotation shaft. A pneumatic tire having one or more bent portions when viewed from at least one of the directions.