Run Flat Tire Side Reinforcement Rubber Composition
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Solution Overview
Problem
Run flat tires experience decreased rigidity at high temperatures, leading to reduced durability during extended running after a puncture, as existing rubber compositions fail to maintain rigidity equal to or greater than that at normal temperatures.
Innovation Solution
A rubber composition for the side reinforcing rubber part with a specific ratio of tensile stress at 50% elongation at 100°C (M50H) to tensile stress at 50% elongation at 23°C (M50N) ranging from 1.0 to 1.3, incorporating diene rubber, phenol type thermosetting resin, methylene donor, and quinoline type age resister, which maintains or increases rigidity at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high hardness compounded rubber composition is used in side reinforcing rubber part, then deformation of tire during run flat running is suppressed, but temperature of side reinforcing rubber part increases and rigidity decreases
Solution Approach 1:
The patent applies parameter changes by modifying the rubber composition formula to include specific ratios of hard rubber (30-70 parts), soft rubber (70-30 parts), and sulfur (2-5 parts). This compositional parameter adjustment enables the rubber to maintain appropriate rigidity at elevated temperatures during run flat operation, resolving the contradiction between initial strength and temperature-induced softening.
Solution Approach 2:
The patent uses composite materials by combining hard rubber and soft rubber in specific proportions within the side reinforcing rubber part. This composite structure allows the material to exhibit both the rigidity needed to suppress deformation and the flexibility to resist excessive temperature-induced softening, effectively resolving the technical contradiction between strength maintenance and temperature resistance.
2Reliability
If rigidity of side reinforcing rubber part is increased to suppress deformation, then run flat durability is improved, but running performance in normal running deteriorates
Solution Approach 1:
The patent applies local quality by providing the side reinforcing rubber part with a specific composition (hard rubber 30-70 parts, soft rubber 70-30 parts) that is localized only in the side wall region. This localized composition provides enhanced run flat durability where needed while keeping the rest of the tire composition optimized for normal running performance, thus resolving the contradiction between reliability and ease of operation.
Solution Approach 2:
The patent uses parameter changes by precisely controlling the ratio of hard rubber to soft rubber (30-70 parts to 70-30 parts) in the side reinforcing rubber part. This parameter optimization ensures the rubber has sufficient rigidity for run flat durability while maintaining appropriate elasticity for normal running comfort and performance, effectively balancing the contradictory requirements.
Data Source
AI summary
A run flat tire having a side wall part reinforced by a side reinforcing rubber part is disclosed. The side reinforcing rubber part is formed from a rubber composition having a ratio (M50H/M50N) of tensile stress (M50H) in 50% elongation at a measurement temperature of 100° C. to tensile stress (M50N) in 50% elongation at a measurement temperature of 23° C. of from 1.0 to 1.3.