Run-Flat Tire Sidewall Reinforcement for Low-Heat Durability
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Solution Overview
Problem
Conventional run-flat tires focus primarily on heat dissipation structures, neglecting material durability, which leads to inadequate high-temperature resistance and reduced durability during run-flat running.
Innovation Solution
A run-flat tire design featuring a sidewall reinforcing layer with specific tensile properties and loss tangent adjustments, combined with an uneven surface portion for enhanced heat dissipation, to improve durability during run-flat conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sidewall reinforcing layer is added to support the tire in a punctured state, then the tire can travel a certain distance even when punctured, but the sidewall reinforcing layer reaches very high temperatures during run-flat running
Solution Approach 1:
The patent changes the material parameters of the sidewall reinforcing layer by specifying precise loss tangent values at different temperatures (|100°Ctan δ-75°Ctan δ|<0.1 and |100°Ctan δ-60°Ctan δ|<0.15). This parameter optimization reduces heat generation during run-flat operation while maintaining the load-bearing capability necessary for run-flat performance.
Solution Approach 2:
The patent employs composite material design by combining the sidewall reinforcing layer with the sidewall rubber composition, where each layer has specifically engineered properties. The sidewall rubber composition also has controlled loss tangent values (|60°Ctan δ-75°Ctan δ|<0.05), creating a composite structure that manages heat generation while providing mechanical support during run-flat conditions.
2Temperature
If various techniques for promoting heat dissipation are applied to reduce temperature rise during run-flat running, then heat dissipation is improved, but the material durability is insufficient
Solution Approach 1:
The patent applies parameter changes to the material properties by precisely controlling the loss tangent values of both the sidewall reinforcing layer and sidewall rubber composition at different temperatures. This material-level parameter optimization enhances durability by reducing thermal stress and heat generation, complementing structural heat dissipation techniques.
3Temperature
If the focus is primarily on heat dissipation structures, then heat dissipation is promoted, but material durability is neglected leading to reduced durability during run-flat running
Solution Approach 1:
The patent shifts focus from purely structural heat dissipation to material property optimization by specifying precise loss tangent parameters for the rubber compositions. This parameter-based approach addresses material durability directly while maintaining heat dissipation performance through reduced hysteresis heating.
Solution Approach 2:
The patent creates a composite system where the sidewall reinforcing layer and sidewall rubber work together with coordinated material properties. Both layers have optimized loss tangent values that complement each other, ensuring both heat dissipation capability and material durability are achieved simultaneously.
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 tire exhibits improved durability and extended running distance by effectively managing temperature rise and heat dissipation through the optimized material properties and surface design.
Implementation Method 1
the difference between the loss tangent of the sidewall reinforcing layer at 100°C and the loss tangent of the sidewall at 75°C, |100°Ctan δ-75°Ctan δ|, is less than 0.1
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Provided is a run-flat tire having improved durability performance during travel while the tire is running flat. A surface section of a sidewall of the run-flat tire is provided with an uneven section. A sidewall reinforcement layer is configured such that a breaking strength TB (MPa) at 100°C × an elongation at break EB (%) is 320 or more and a loss tangent 100°C tanδ at 100°C is 0.06 or less, and the sidewall is configured such that a loss tangent 60°C tanδ at 60°C is 0.17 or less and | 60°Ctanδ -75°Ctanδ | is less than 0.05.