Pneumatic tire

Abstract

Provided is a pneumatic tire comprising a side reinforcement layer in a side wall section, wherein the structure of a bead section is improved so as to make it possible to reduce tire weight while maintaining the durability of the tire. The width W0 of a layer with the greatest number of rows among a plurality of layers that make up a bead core 5, the width W1 on the innermost side in the tire radial direction, and the width W2 on the outermost side in the tire radial direction are set so as to fulfill the relationships W1 > W2 and W2 <= 0.5 * W0; the layer of the width W0 is positioned more inward in the tire radial direction from the center position of the bead core 5 in the tire radial direction; a carcass layer 4 is folded back while being curved along a peripheral edge of the bead core; a folded-back section 4B of the carcass layer 4 extends toward side wall sections 2 while maintaining contact with a main section 4A of the carcass layer 4; the proportion of rubber in a closed region formed by the main section 4A of the carcass layer 4 and the folded-back section 4B is 0.1-15%; and the cross-sectional area S2 and the hardness H2 of a filler layer 9 disposed on the outer side of the carcass layer 4 in the tire width direction and the cross-sectional area S1 and the hardness H1 of a side reinforcement layer 8 fulfill the relationship 0.12 <= (S2 * H2) / (S1 * H1) <= 0.50.

Description

technical field [0001] The present invention relates to a pneumatic tire provided with a side reinforcing layer in a sidewall portion, and more specifically, to a pneumatic tire capable of reducing the weight of the tire while maintaining the durability of the tire by improving the structure of the bead portion. Background technique [0002] Generally, bead cores and bead fillers are embedded in bead portions of pneumatic tires. Also, in pneumatic tires (so-called run-flat tires) that can safely travel a certain distance even if a tire blows out, the side reinforcing layer (which is crescent-shaped from the cross-sectional shape) for supporting the load load of the vehicle when the tire blows out A layer made of hard rubber) is provided on the side wall portion. In such a tire, the inner end portion of the side reinforcing layer in the tire radial direction may reach the vicinity of the bead portion, and the vicinity of the bead portion may become thicker, thereby tending t...

AI Technical Summary

Problems solved by technology

However, in such a tire, even if the weight of the tire is successfully reduced, the rigidity near the bead portion will decrease, so the durability of the tire may not be sufficiently obtained, and further measures are required.

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