JPH04175149A - Manufacture of pneumatic radial tire - Google Patents

Abstract

PURPOSE:To prevent the disturbance of the cords of a carcass layer by bonding a rubber sheet irradiated with electron beam over the range from a shoulder part to a side part to one of the inner and outer side surfaces of the carcass layer over the periphery of a tire. CONSTITUTION:When a carcass layer 2 is formed by winding a carcass sheet around a molding drum in a green tire molding stage, a rubber sheet preliminarily irradiated with electron beam is bonded to one of the inner and outer side surfaces of the carcass layer 2 over the periphery of a tire. Since the rubber sheet is slightly advanced in curing because of the irradiation with electron beam, even when the carcass cords over the range from a shoulder part 3 to a side part 4 expands at the time of the vulcanization and molding of the tire, the movement of them is suppressed. Further, since larger tensile force is applied to the outside of the carcass layer 2 as compared with the inside thereof when internal pressure is applied to the green tire, when the rubber sheet 1 is set to the outside of the carcass layer 2, the tension thereof can be effectively absorbed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention improves uniformity by eliminating the disorder of the cords of the carcass layer that occurs from the shoulder part to the side part during vulcanization molding of a green tire. The present invention relates to a method for manufacturing a pneumatic radial tire.

[Conventional technology]

When vulcanizing a pneumatic radial tire, the green tire inserted into a mold is pressed from the inside against the inner surface of the mold in which a balloon-like bladder is inflated. When applying internal pressure to a green tire in this way, the carcass cord in the area from the shoulder area to the side area is easier to move than in the trend area reinforced by the heald layer. It is recognized that disturbances occur.

This carcass cord disorder poses a problem in that it not only reduces the uniformity of the tire but also reduces the elongation of the carcass cord.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned circumstances, and is a pneumatic insert that improves uniformity by eliminating the disordered arrangement of carcass cords that occurs from the shoulder part to the side part during vulcanization molding of a green tire. The purpose of the present invention is to provide a method for manufacturing radial tires.

[Means to solve the problem]

In the present invention, when a carcass sheet is wound around a forming drum to form a carcass layer, a rubber sheet that has been previously irradiated with an electron beam from a shoulder portion to a side portion is applied to at least one of the inner and outer surfaces of the carcass layer. It is characterized by being attached over one circumference of the tire.

In this way, in the present invention, a rubber sheet that has been previously irradiated with electron beams is attached to the inner or outer surface of the carcass layer in the region from the shoulder part to the side part, so that the rubber sheet has been slightly cured. The placement of the rubber layer suppresses the movement of the carcass cords in this area, preventing the cord arrangement from becoming disordered, thereby making it possible to improve the uniformity of the tire.

Hereinafter, the configuration of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is an explanatory half-sectional view in the meridian direction showing an example of a pneumatic tire obtained by the present invention. In FIG. 1, both ends of the carcass layer 2 are folded back and rolled up around the bead core 7 from the inside of the tire to the outside. In trend 8 of this carcass layer 2, Hell I is on the outside.
- The layers 9 and 9° are arranged in an annular manner over one circumference of the tire in the tire circumferential direction. An extrusion rubber 5 is provided between the carcass layer 2 and the end of the heald layer 9.

Furthermore, a rubber sort 1 is arranged on the outer side of the carcass layer 2 from the shoulder part 3 to the side part 4 over one circumference of the tire. This comb sheet 1 may be arranged both inside and outside the carcass layer 2 as in the embodiment shown in FIG. 2, or it may be arranged inside the carcass layer 2 as in the embodiment shown in FIG. .

In the method for manufacturing a pneumatic radial tire of the present invention, when forming a carcass layer by winding a carcass sheet on a forming drum in the green tire forming step of a tire having the above-described structure, the inner surface of the carcass layer and A rubber sheet 1 which has been irradiated with an electron beam in advance is attached to at least one of the outer surfaces of the drum over one circumference of the drum and one circumference of the tire. Since this rubber sheet 1 has been irradiated with electron beams in advance, it has been slightly cured, so this carcass cord from the shoulder part to the side part will not move even if it is expanded during vulcanization molding of the green tire. will be suppressed. The thickness of such a rubber sheet 1 is preferably in the range of 0.2 mm to 1.2 mm.

Further, the area where the rubber sheet 1 is placed may be on both the inner and outer surfaces from the shoulder part to the side part of the carcass layer, but preferably, as shown in FIG.
It is desirable to set the outer side of the carcass layer 2 from the position overlapping with the bead filler to the vicinity of the upper end of the bead filler. This is because when internal pressure is applied to the green tire, a larger tensile force is applied to the outer side of the carcass layer 2 than the inner side, so the rubber sheet 1 can effectively absorb the tensile force. Also,
The upper end of the rubber sheet 1 is located at the extrusion rubber 5.
It is preferable that the lower end side be at least 10 points away from the trend center side, and the lower end side be at least 10 points away from the bead core 7 side.

〔Effect of the invention〕

As described above, according to the present invention, when a carcass sheet is wound around a forming drum to form a carcass layer, at least one of the inner and outer surfaces of the carcass layer from the shoulder part to the side part is injected with an electron beam in advance. Since the irradiated rubber sheet is attached all around the tire, it is possible to prevent the cords of the carcass layer from being disturbed when internal pressure is applied during green tire vulcanization, and the uniformity of the tire can be improved.

[Brief explanation of the drawing]

1 to 3 are explanatory half-sectional views in a meridian direction showing an example of a pneumatic tire obtained by the present invention, respectively. ■...Rubber sheet, 2...Carcass layer, 3...Shoulder part, 5...Side part. Figure 1 Figure 2

Claims (1)

[Claims] When forming a carcass layer by winding a carcass sheet on a forming drum, a rubber sheet that has been previously irradiated with electron beams from the shoulder part to the side part is applied to at least one of the inner and outer surfaces of the carcass layer around one circumference of the tire. A method for manufacturing a pneumatic radial tire that is adhered across the board.