Run-flat tire

Abstract

Provided is a run-flat tire that achieves high levels of both run-flat durability and ride comfort, and minimizes weight increase. In a sidewall-reinforced run-flat tire, the minimum thickness section being positioned between the belt layer end section and the tire cross-sectional height (SH) 70% position, the relationship between the thickness (Gmin) of the minimum-thickness section and the thickness (Gmax) of the maximum thickness section (17) is defined as 0.5 × Gmax ≤ Gmin ≤ 0.8 × Gmax; the relationship between the length (Lmin) of the thin region and the tire cross-sectional height (SH) is defined as 0.18 × SH ≤ Lmin ≤ 0.26 × SH; the relationship between the weight (Wr) of the sidewall-reinforcement layer, the tire total weight (Wt), and the tire oblateness (R) is defined as 0.08 × Wt × (1 - 0.2 × (1 - R / 50)) ≤ Wr ≤ 0.18 × Wt × (1 - 0.2 × (1 - R / 50)); the relationship between the thickness (Ga) at the rim-check line of the outer-side rubber portion outward of the carcass layer, and the maximum thickness (Gb) thereof, is defined as 0.8 × Gb ≤ Ga ≤ 1.0 × Gb; and the relationship between the thickness (Gc) at the rim-check line of the inner-side rubber portion inward of the carcass layer and the thickness (Ga) is defined as 0.7 × Ga ≤ Gc ≤ 1.0 × Ga.

Description

technical field [0001] The present invention relates to a sidewall-reinforced run-flat tire. More specifically, it relates to a tire capable of achieving high levels of durability during run-flat running and ride comfort during normal running while suppressing weight increase. For minimal run-flat tires. Background technique [0002] Conventionally, as a run-flat tire capable of running in a blown state, a sidewall-reinforced type run-flat tire (for example, Refer to Patent Documents 1 to 2). [0003] In such sidewall-reinforced run-flat tires, in order to improve the durability during run-flat driving, the thickness of the sidewall reinforcement layer is generally increased, and / or a hardened tire is used for the sidewall reinforcement layer. rubber composition. [0004] However, in the case where the thickness of the sidewall reinforcing layer is increased and / or the hardness of the rubber composition constituting the sidewall reinforcing layer is increased, there is a ...

AI Technical Summary

Problems solved by technology

[0004] However, in the case where the thickness of the sidewall reinforcing layer is increased and / or the hardness of the rubber composition constituting the sidewall reinforcing layer is increased, there is a problem that, along with the increase in the rigidity of the sidewall portion, the Ride comfort will deteriorate, or tire weight will increase significantly

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