Radial tire with circumferential spirally wound belt layer

Abstract

A belt layer in which one or more belt cords covered with rubber are arranged spirally wound substantially in parallel in the tire circumferential direction, and at least one layer is arranged on the outer periphery of the main body ply. The belt cord has a small increase ratio of the tensile load with respect to an increase in the elongation at a predetermined elongation or less, and a large increase ratio of the tensile load when the elongation exceeds the predetermined elongation. Therefore, since the belt cords expand together with the unvulcanized compound rubber with a small tensile load during vulcanization molding, and the expansion of the main body ply cords is not prevented, the normal shape of the raw tire is maintained and expanded, Reliably fit and vulcanize each part.

Description

technical field [0001] The present invention relates to a radial tire in which belt cords of a belt are helically wound and arranged substantially parallel to the circumferential direction of the tire. Background technique [0002] In order to further improve the safety of vehicles, it is strongly required to improve the braking performance and steering stability of tires in contact with the road surface. In addition, considering environmental aspects and increasing fuel consumption, there is also a high demand for reducing the weight of tires. In order to meet these requirements, Japanese Patent Application Laid-Open No. 62-152904 describes a radial tire. The ultraviolet tire is arranged as follows: The tire tread portion is a main body ply cord that is folded back at the bead core of the bead portion through the tire sidewall portion. On the outer peripheral side of the tire tread portion of the main body ply, a layer of steel wire is arranged along the circumferential di...

AI Technical Summary

Problems solved by technology

Utilizing a general steel cord or aramid cord which has a large increase in tensile load relative to an increase in elongation and is substantially inextensible, it does not elongate by 0.5 under the pressure applied inside the green tire. ~ 3%, when expanding, there is a defect that the expansion is prevented by the belt cord that does not expand from the main body ply cord, and the normal shape cannot be maintained

Conversely, in radial tires using cords of PET or nylon fibers whose percentage of increase in tensile load is small relative to the increase in elongation for belt cords, there is a problem that sufficient clamping effect cannot be obtained after vulcanization molding. The problem

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