Run-Flat Tire Support Rubber for Low Heat and Reuse
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Solution Overview
Problem
Traditional run-flat tires face issues with excessive thickness, hardness, high heat generation, and poor comfort due to their supporting structure, leading to noise, high rolling resistance, and high fuel consumption, and the support rubber is prone to fatigue damage, requiring replacement after a single use, which is costly and environmentally unfriendly.
Innovation Solution
An outside support rubber for run-flat tires is formulated with specific components and tested under controlled conditions to ensure low modulus loss, high modulus retention, excellent tensile strength, and reduced heat generation, using a combination of liquid process natural rubber, low cis-polybutadiene rubber, aramid short fibers, and silica, with a test method to evaluate performance during reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional support rubber is used to provide supporting performance, then the tire can drive stably at zero pressure, but the support rubber is prone to fatigue damage and thermal damage, requiring replacement after single use
Solution Approach 1:
The support rubber is divided into two distinct layers: an inner support rubber layer and an outer support rubber layer. The inner layer uses natural rubber-based material for initial supporting performance, while the outer layer uses synthetic rubber-based material for enhanced fatigue and thermal resistance during reuse
Solution Approach 2:
The patent employs composite material strategy by combining natural rubber and synthetic rubber in a layered structure. Each layer has optimized composition: inner layer contains natural rubber, polybutadiene rubber, and carbon black; outer layer contains synthetic rubber, silica, and carbon black. This composite approach allows the tire to achieve both initial supporting performance and extended service life through reuse
2Reliability
If the support rubber is made thicker and harder to improve supporting performance, then the tire can maintain rigidity, but heat generation increases and heat dissipation is delayed, causing thermal damage
Solution Approach 1:
Different regions of the support rubber have different material properties optimized for their specific functions. The inner layer uses natural rubber for initial support with moderate heat generation, while the outer layer uses synthetic rubber with better heat dissipation properties. The thickness of each layer is specifically optimized: inner layer 5-15mm, outer layer 2-8mm
Solution Approach 2:
The patent optimizes material composition parameters to control heat generation. The inner layer uses carbon black (20-40 phr) for reinforcement, while the outer layer uses silica (20-40 phr) which provides better heat dissipation. The vulcanization system parameters are also optimized with specific sulfur (0.5-2 phr) and accelerator (1-3 phr) content to achieve appropriate crosslinking density and heat resistance
3Ease of operation
If natural rubber is used in support rubber to improve elasticity, then the rubber has good flexibility, but heat resistance is poor and thermal damage occurs during zero-pressure driving
Solution Approach 1:
The support rubber is segmented into two layers with different material compositions. The inner layer uses natural rubber for flexibility and initial supporting performance, while the outer layer uses heat-resistant synthetic rubber to protect against thermal damage during zero-pressure driving
Solution Approach 2:
The patent creates a composite structure combining natural rubber-based inner layer with synthetic rubber-based outer layer. The natural rubber provides elasticity and flexibility, while the synthetic rubber contributes heat resistance and fatigue durability, achieving synergistic effects
4Reliability
If the support rubber structure is optimized for supporting performance, then the tire can drive 80km at 80km/h at zero pressure, but rolling resistance increases and fuel consumption rises
Solution Approach 1:
The patent optimizes the thickness parameters of each layer to balance supporting performance and rolling resistance. The inner layer thickness is controlled at 5-15mm and outer layer at 2-8mm, ensuring sufficient support while minimizing energy loss. The material composition is also optimized with controlled filler content (carbon black 20-40 phr, silica 20-40 phr) to reduce hysteresis loss
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 solution provides a support rubber with improved durability, reduced heat generation, and enhanced tensile fatigue resistance, allowing the tire to be reused after repair, thus reducing waste and environmental impact while maintaining performance.
Implementation Method 1
vulcanization: placing an unvulcanized outside support rubber for the run-flat tire in a mold cavity of a rubber processing analyzer, and setting a vulcanization temperature to be 161°C, a vulcanization time to be 15min
Implementation Method 2
the support rubber will be subjected to thermal damage and mechanical damage when the run-flat tire is driving at zero pressure
Implementation Method 3
high heat generation are caused
Data Source
Figure 1
Figure 2
AI summary
An outside support rubber for a run-flat tire, a run-flat tire and a test method are provided in the present application. A modulus loss rate of the outside support rubber satisfies: |1-G'2/G'1|≤6%, wherein G'1 is a modulus obtained before a zero-pressure driving simulation of the run-flat tire, G'2 is a modulus obtained after the zero-pressure driving simulation of the run-flat tire, and G'1 and G'2 are both measured under condition that a temperature is 55-60°C, a frequency is 600cpm, and a strain is 7%. When the outside support rubber is used in a run-flat tire, a sufficient supporting performance, a tensile fatigue resistance and an excellent low heat generation performance can be ensured, so that the run-flat tire can be reused after being repaired instead of replacement, and sustainability and low carbon are achieved