Pneumatic Tire Tread Cap Layer Flexibility Design
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Solution Overview
Problem
Tires face a challenge in improving quietness without compromising steering stability, as thicker treads for quietness can lead to decreased stiffness and stability issues.
Innovation Solution
A pneumatic tire design featuring a tread with a base layer and a cap layer, where the cap layer includes a center element and side elements with varying flexibility, and a specific pattern of circumferential and lateral grooves, along with dead-end sipes, to balance quietness and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thick tread is adopted to improve quietness, then quietness is improved, but the stiffness of the tread part is decreased, resulting in a decrease in steering stability
Solution Approach 1:
The cap layer is designed with different flexibility characteristics in different regions: the center element has different flexibility than the side elements. This local differentiation allows the tread to provide quietness where needed while maintaining steering stability through the stiffer center region
Solution Approach 2:
The tread is constructed as a composite structure with a base layer and a cap layer, where the cap layer itself contains multiple elements with different flexibility properties. This composite construction enables simultaneous achievement of quietness and steering stability
Data Source
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AI summary
In a tire 2, a cap layer 28 of a tread 4 includes a center element 30 and a pair of side elements 32, and each side element 32 is more flexible than the center element 30. A hardness of a base layer 26 of the tread 4 is equal to a hardness of each side element 32, or the base layer 26 is more flexible than each side element 32. The cap layer 28 in each shoulder land portion 50s of the tread 4 includes the side element 32. A plurality of lateral grooves 52 are formed on each shoulder land portion 50s, and the plurality of lateral grooves 52 each have an end portion within the shoulder land portion 50s and extend from the end portion toward an end of the tread 4.