Tire Side Reinforcing Rubber Composition for Run Flat Durability
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Solution Overview
Problem
Current tires face challenges in achieving improved run flat durability, ride comfort, side cut resistance, and steering stability, particularly with the increasing performance demands of passenger cars.
Innovation Solution
The tire design incorporates a side reinforcing rubber layer and bead filler using a rubber composition with specific elongation ratios and dynamic tensile storage modulus, combined with a carcass ply featuring an organic fiber cord with controlled elongation and toughness, and an adhesive treatment using thermoplastic polymers and resorcinol-formalin latex adhesive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a side reinforcing rubber layer and bead filler using conventional rubber composition are used, then the rigidity of the side wall part is enhanced, but the run flat durability is insufficient
Solution Approach 1:
The patent changes the physical and chemical parameters of the rubber composition by specifying precise ranges for elongation ratios (X/Y between 1.00-1.15), dynamic tensile storage modulus (E' ≥ 9.0 MPa), and loss tangent summation (S ≤ 6.0). These parameter optimizations resolve the contradiction by achieving both sufficient rigidity and improved run flat durability through scientifically controlled material properties.
Solution Approach 2:
The patent employs composite materials by combining specific rubber components (20% or more modified conjugated diene based polymer) with carbon black and phenol resin in defined proportions. This composite approach enables the rubber composition to simultaneously provide the rigidity needed for side wall reinforcement and the thermal stability required for run flat durability.
2Reliability
If the rubber composition is optimized for run flat durability, then the run flat durability is improved, but the ride comfort deteriorates
Solution Approach 1:
The patent carefully balances the rubber composition parameters to resolve this contradiction. By controlling the elongation ratio X/Y within 1.00-1.15 and the loss tangent summation S to be 6.0 or less, the composition achieves optimal elasticity and damping characteristics that provide both run flat durability and acceptable ride comfort.
Solution Approach 2:
The patent applies different rubber compositions to different parts of the tire structure. The side reinforcing rubber layer and bead filler use the optimized composition for run flat durability, while other tire parts maintain compositions suited for comfort, achieving local optimization that resolves the overall contradiction.
3Strength
If the rubber composition is hardened to improve side cut resistance, then the side cut resistance is improved, but the steering stability in normal running deteriorates
Solution Approach 1:
The patent resolves this contradiction by optimizing the rubber composition parameters within specific ranges rather than simply hardening the material. The dynamic tensile storage modulus E' is set to 9.0 MPa or more while controlling the loss tangent summation S to be 6.0 or less, achieving a balance that provides both side cut resistance and steering stability.
Solution Approach 2:
The patent uses a composite material system combining modified conjugated diene based polymer, carbon black, and phenol resin in specific proportions. This composite structure provides the toughness needed for side cut resistance while maintaining the flexibility required for steering stability through the synergistic effects of the components.
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
This configuration enhances run flat durability, maintains ride comfort, and improves side cut resistance and steering stability by preventing rubber softening and maintaining structural integrity under various temperature conditions.
Implementation Method 1
a rubber composition comprising 20% by mass or more of a modified conjugated diene based polymer, and satisfying Expression (1) in terms of an elongation X under a stress of 6.5 MPa at 180° C. and an elongation Y under a stress of 6.5 MPa at 25° C. after vulcanization
Implementation Method 2
a dynamic tensile storage modulus E′ after vulcanization in a specific range and a summation S of tan δ values at 28° C. to 150° C. after vulcanization in a specific range
Implementation Method 3
an adhesive treatment using thermoplastic polymers and resorcinol-formalin latex adhesive
Data Source
AI summary
The present invention provides a tire improved in the run flat durability, having at least one member selected from the group consisting of a side reinforcing rubber layer and a bead filler using a rubber composition comprising a rubber component containing 20% by mass or more of a modified conjugated diene based polymer, satisfying Expression (1) in terms of the elongation X under a stress of 6.5 MPa at 180° C. and the elongation Y under a stress of 6.5 MPa at 25° C. after vulcanization.1.00≤X/Y≤1.15 (1)