Run-flat Tire Sidewall Support Composition
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Solution Overview
Problem
Tire manufacturers seek to improve the rolling resistance and durability of run-flat tires that operate with little or no inflation pressure, as existing rubber inserts impact rolling resistance and durability.
Innovation Solution
A rubber composition for sidewall supports in tires, combining polybutadiene rubber with high Mooney viscosity and low-surface area, high-structure carbon black, along with a second rubber component like natural rubber or polybutadiene, to create a low-rigidity, low-hysteresis material that enhances rolling resistance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick rubber inserts are used to support vehicle load at reduced pressure, then load-bearing capability is improved, but rolling resistance increases
Solution Approach 1:
The patent changes the chemical composition parameters of the rubber compound by incorporating specific silica treatments and vulcanizing agents that reduce hysteresis losses while maintaining structural integrity. This allows the sidewall support to bear vehicle loads without excessive energy dissipation, thereby reducing rolling resistance while preserving load-bearing capability.
Solution Approach 2:
The patent uses a composite rubber compound combining multiple elastomers (natural rubber, polybutadiene, polyisoprene) with specifically treated silica and vulcanizing agents. This composite structure provides both the mechanical strength needed for load support and the optimized viscoelastic properties that minimize hysteresis and rolling resistance.
2Strength
If thick rubber inserts are used to support vehicle load at reduced pressure, then load-bearing capability is improved, but durability decreases
Solution Approach 1:
The patent optimizes the chemical composition parameters including silica treatment levels, vulcanizing agent types and quantities, and elastomer ratios. These parameter changes create a rubber compound with improved resistance to fatigue, cracking, and degradation under sustained load conditions, thereby enhancing durability while maintaining load-bearing capability.
Solution Approach 2:
The multi-component composite rubber compound provides synergistic effects where natural rubber contributes to tensile strength and durability, polybutadiene provides elasticity and fatigue resistance, and the specifically treated silica-vulcanizing agent system enhances overall structural stability and resistance to degradation under load.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The described rubber composition improves the endurance and reduces rolling resistance of run-flat tires, allowing them to maintain performance over a reasonable distance with minimal inflation pressure.
Implementation Method 1
a cross-linkable elastomer composition having, per 100 parts by weight of rubber, a polybutadiene rubber having a Mooney viscosity of between 55 and 85
Implementation Method 2
a low-surface area, high-structure carbon black
Data Source
AI summary
Run-flat tires having a sidewall support that is manufactured from particular rubber composition. These compositions are based upon a cross-linkable elastomer composition having, per 100 parts by weight of rubber, a polybutadiene rubber having a Mooney viscosity of between 55 and 85 and a low-surface area, high- structure carbon black. An additional second rubber component may also be included in the elastomer composition. The low- surface area, high- structure carbon black may be characterized as having a nitrogen surface area of between 15m 2 /g and 25m 2 /g and a COAN of between 65 ml/100 g and 85 ml/100 g.