Manufacturing method of run-flat tire

Abstract

A method of manufacturing a run-flat tire capable of manufacturing a run-flat tire with excellent uniformity due to its less occurrence of eccentricity than in conventional methods by simple facility and steps. The method comprises a step for disposing an inner liner rubber (19), reinforcement rubber members (18) reinforcing side wall parts on both sides, and a carcass ply (14) at the prescribed outer peripheral positions of a molding drum, a step for disposing a pair of first beads (1a) and bead fillers (12) and toroidally deforming the inside of the first bead (1a), a step for curling up and stamping the end part (14b) of the carcass ply (14), a step for stamping rubber members (13a) and (13b) forming annular swelled parts on the sides of the bead filler (12) of a toroidal formed product, and a step for forming second beads (1b) by spirally stamping cords (BW) on the formed product while rotating the formed product after that stamping about the axis thereof.

Description

technical field [0001] The present invention relates to a side-reinforced run-flat tire in which a second bead is disposed on an annular bulging portion bulging outward in the tire width direction of the bead portion, and a method for manufacturing the same. Background technique [0002] A run-flat tire is a tire that can safely travel a certain distance even if the air pressure inside the tire drops due to a failure such as a flat. As one of the tire structures for enabling such a run-flat run, there is known a run-flat tire having a reinforcing rubber layer on a sidewall portion. With such a run-flat tire, when the air pressure inside the tire decreases, the reinforcing rubber layer supports the tire and prevents the tire from completely flattening, thereby allowing run-flat running. [0003] However, in a state where the air pressure inside the tire is lowered, there is a problem that the bead portion tends to come off from the rim because the bead portion is less press...

AI Technical Summary

Problems solved by technology

[0003]However, in the state where the air pressure inside the tire is lowered, there is a problem that since the pressing force of the bead portion to the rim is weakened, the fitting force with the rim is lowered, Causes the bead portion to be easily detached from the rim

[0005] This kind of run-flat tire has such a problem: when running flat, if the side reinforcement part bends to generate tension in the carcass layer, the tire toe is easy to Lifted so the bead is easy to fall off

[0008] However, in the above-mentioned manufacturing method, when disposing the annular second bead 1b, a mechanism for affixing without eccentricity with respect to the tire axis is required.

In addition, when the assembly of bead wires is manufactured in advance, there is also a problem that the support mechanism for winding and the device for bundling the assembly are relatively large.

In addition, there is a problem that since the second bead 1b is arranged before expanding and deforming the molded product into a tire shape, eccentricity and cross-sectional shape of the second bead 1b are likely to occur when the molded product is expanded and deformed. Deformation, etc.

However, these manufacturing methods employ a method in which an annular core having the same shape as the inner surface of the tire is used, and constituent members are sequentially arranged (pasted) on the annular core, and in the case of a run-flat tire, there is no using this method

Therefore, a method of forming a bead by spirally winding a bead wire on a molded product has not been known so far in a method of manufacturing a run-flat tire.

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