Two-Wheeled Vehicle Tire Cap Rubber Thickness Optimization
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Solution Overview
Problem
Two-wheeled vehicle tires face challenges in achieving balanced steering stability, durability, and wear resistance due to the heat generation and physical property differences between cap and base rubber layers with high loss tangent values.
Innovation Solution
A two-wheeled vehicle tire design featuring a tread rubber composition with a cap rubber layer having a higher 300% modulus and lower loss tangent than the base rubber layer, optimized in thickness and land ratio across different regions of the tread surface to enhance wear resistance and durability while maintaining steering stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rubber with large loss tangent is used in the cap rubber layer to improve impact absorbing property, then steering stability is improved, but heat generation increases which deteriorates durability and wear resistance
Solution Approach 1:
The tread rubber is segmented into two distinct layers: a cap rubber layer (40-90% thickness) with high loss tangent (0.08-0.15) for steering stability and impact absorption, and a base rubber layer (10-60% thickness) with low loss tangent (0.04-0.09) for reduced heat generation. This segmentation allows each layer to perform its specialized function without compromising the other.
Solution Approach 2:
Different regions of the cap rubber layer have different thicknesses optimized for their specific functions: the crown region has greater thickness (40-90% of total tread rubber thickness) for superior wear resistance and steering stability, while shoulder regions have lesser thickness (10-30%) for flexibility and cornering performance. This local quality variation optimizes overall tire performance.
2Reliability
If cap rubber thickness is increased to improve wear resistance, then durability is improved, but weight and rolling resistance increase
Solution Approach 1:
The cap rubber layer thickness is locally optimized: in the crown region it constitutes 40-90% of the total tread rubber thickness to provide superior wear resistance where the tire contacts the ground most frequently, while in the shoulder regions it constitutes only 10-30% to reduce weight and improve flexibility for cornering maneuvers.
3Reliability
If loss tangent of cap rubber is increased to improve grip, then steering stability is improved, but heat generation increases reducing durability
Solution Approach 1:
The rubber composition is segmented into two layers with different loss tangent values: the cap rubber layer has high loss tangent (0.08-0.15) for superior grip and steering stability, while the base rubber layer has low loss tangent (0.04-0.09) to minimize heat generation and maintain durability during prolonged use.
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 design improves wear resistance, durability, and steering stability by balancing the physical properties of the cap and base rubber layers, reducing heat generation and enhancing grip and ride comfort during various riding conditions.
Implementation Method 1
loss tangent (tan δc) of the cap rubber is smaller than loss tangent (tan δb) of the base rubber
Implementation Method 2
300% modulus (M300c) of the cap rubber is greater than 300% modulus (M300b) of the base rubber
Data Source
AI summary
A two-wheeled vehicle tyre includes a tread portion including a tread rubber. The tread rubber includes a cap rubber forming a tread surface and a base rubber disposed radially inwardly of the cap rubber. 300% modulus (M300c) of the cap rubber is greater than 300% modulus (M300b) of the base rubber. Loss tangent (tan δc) of the cap rubber is smaller than loss tangent (tan δb) of the base rubber. The tread surface includes a crown region centered on a tyre equator and a pair of shoulder regions located axially outwardly of the crown region, and a thickness of the cap rubber in the crown region is greater than a thickness of the cap rubber in each of the shoulder regions.