Pneumatic Tire Tread Geometry for Low Rolling Resistance Braking
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Solution Overview
Problem
Existing pneumatic tire technologies face challenges in achieving reduced rolling resistance in normal load loading states while maintaining sufficient frictional force for dry braking performance, as previous methods either compromise ground contact width or increase rolling resistance in brake load loading states.
Innovation Solution
A pneumatic tire design that optimizes the ratio of tread width to total tire width and ground contact width in both normal and brake load loading states, ensuring a balanced reduction in rolling resistance and enhancement of dry braking performance by adjusting the tire's structural components and inflation pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thickness of the rubber that forms the shoulder region is decreased to reduce rolling resistance, then rolling resistance is reduced, but ground contact width is insufficient and frictional force in brake load loading state is not obtained
Solution Approach 1:
The patent applies local quality by differentiating the rubber thickness in different regions of the tire. Specifically, the shoulder region rubber thickness is set to 35% to 65% of the center line rubber thickness, creating a localized thinning effect that reduces overall rolling resistance while preserving sufficient ground contact area through the optimized ratio relationships.
Solution Approach 2:
The patent utilizes parameter changes by optimizing specific geometric ratios: the tread width to total tire width ratio (TW/SW) is set to 0.75 to 0.90, and the ground contact width ratio (CW100/CW70) is set to 1.05 to 1.20. These parameter optimizations enable the tire to achieve reduced rolling resistance while maintaining adequate frictional force for braking.
2Loss of energy
If the ratio TR3/TR2 is set to 1.10 to 1.50 to reduce rolling resistance at high internal pressure, then rolling resistance is reduced, but the tread central region bulges too much and ground contact width is insufficient
Solution Approach 1:
The patent optimizes the ratio of tread width to total tire width (TW/SW) to be within 0.75 to 0.90, which controls the bulging behavior of the tread central region. This parameter optimization prevents excessive bulging while maintaining sufficient ground contact width, thereby achieving reduced rolling resistance without compromising braking performance.
3Area of stationary object
If the tread width to total tire width ratio is increased to ensure sufficient ground contact width, then ground contact width is improved, but rolling resistance increases
Solution Approach 1:
The patent applies local quality by creating a non-uniform rubber thickness distribution across the tire width. The shoulder region rubber thickness is optimized to be 35% to 65% of the center line rubber thickness, which allows the tire to achieve sufficient ground contact width through the optimized TW/SW ratio while minimizing rolling resistance through the localized thinning effect.
Data Source
AI summary
In a state in which the pneumatic tire is mounted on a regular rim and inflated to 5% of a specified internal pressure, a tread width is TW, a total tire width is SW in a tire meridian cross-sectional view, a relationship of 0.80≤TW/SW≤0.95 is satisfied, a ground contact width at a load of 100% of a maximum load capacity is CW100, a ground contact width at a load of 70% of the maximum load capacity is CW70, and a relationship of 1.04≤CW100/CW70≤1.15 is satisfied.