Pneumatic Tire Undertread Rubber Thickness Distribution
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Solution Overview
Problem
Current pneumatic tire technologies fail to simultaneously reduce tire noise and enhance steering stability, with existing solutions focusing on tire structure and material selection without comprehensive consideration of rubber hardness and thickness distribution.
Innovation Solution
A pneumatic tire design featuring a carcass with a belt layer and tread rubber, where the tread rubber includes undertread and cap tread rubber with specific hardness and thickness ratios, optimized to balance noise reduction and stability performance by varying the cross-sectional areas and dimensions across the tire width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the tread rubber is made uniformly hard to improve steering stability, then steering stability is improved, but tire noise increases
Solution Approach 1:
The tread rubber is designed with different hardness characteristics in different regions: the center region uses harder rubber for steering stability, while the shoulder region uses softer rubber to reduce noise. This local differentiation allows each region to optimize its function without compromising the other.
Solution Approach 2:
The tread rubber is segmented into distinct regions (center and shoulder) with different material properties. The center region tread rubber and shoulder region tread rubber are formulated with different hardness levels to independently address steering stability and noise reduction requirements.
2Object-generated harmful factors
If the tread rubber is made uniformly soft to reduce tire noise, then tire noise is reduced, but steering stability deteriorates
Solution Approach 1:
The tread rubber is designed with different hardness characteristics in different regions: the center region uses harder rubber for steering stability, while the shoulder region uses softer rubber to reduce noise. This local differentiation allows each region to optimize its function without compromising the other.
Solution Approach 2:
The tread rubber is segmented into distinct regions (center and shoulder) with different material properties. The center region tread rubber and shoulder region tread rubber are formulated with different hardness levels to independently address steering stability and noise reduction requirements.
3Force
If the ground contact width is increased to improve traction, then traction is improved, but tire noise increases due to excessive rubber deformation
Solution Approach 1:
The tread rubber is designed with different hardness characteristics in different regions: the center region uses harder rubber for steering stability, while the shoulder region uses softer rubber to reduce noise. This local differentiation allows each region to optimize its function without compromising the other.
Data Source
AI summary
In a state in which a pneumatic tire is mounted on a specified rim, inflated to 92% of a specified internal pressure, and loaded with a load of 75% of the maximum load capacity, an average thickness of an undertread rubber is smaller in a center region than in a shoulder region, a ratio (CAO/UAO) is 0.15 or more and 0.95 or less, a ratio (UAI/UAO) is less than 1, and a ratio (L/W) is 0.29 or more and 0.51 or less, in a tire meridian cross-sectional view, where CAO, UAO and UAI are cross-sectional areas of the cap tread rubber, the undertread rubber, and the undertread rubber in the center region, respectively, L is a tire width direction dimension from a defined intersection point to a ground contact edge, and W is a tire width direction dimension of each shoulder region.