Pneumatic Tire Sidewall Thickness and Bead Width Optimization
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Solution Overview
Problem
Pneumatic tires with thinned sidewall portions face challenges in maintaining mountability on rims due to reduced rigidity, leading to deformation and difficulty in fitting bead portions to the rim.
Innovation Solution
The sidewall portions are thinned to an average thickness of 1.0 mm to 3.0 mm at the deflection region, and the bead base width is set to 115% to 130% of the tread development width, ensuring stable mountability by maintaining sufficient spacing between bead portions and using a mold to vulcanize the tire with a bead base width 1 inch to 3 inches larger than the rim width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sidewall portions are thinned to reduce vertical spring constant, then ride comfort and ground contact are improved, but the rigidity of the sidewall portions decreases leading to degraded mountability on rims
Solution Approach 1:
The patent applies local quality by creating non-uniform sidewall thickness distribution: the sidewall is thinned in the deflection region (20-80% of sidewall height from bead) to reduce vertical spring constant and improve ride comfort, while maintaining greater thickness at the bead region to preserve rigidity for mountability. This localized differentiation resolves the contradiction by optimizing thickness for different functional requirements at different locations.
2Ease of operation
If the bead base width is increased to improve mountability, then fitting to rim becomes easier, but the tire structure becomes more complex
Solution Approach 1:
The patent applies parameter changes by optimizing the bead base width to a specific range (115-130% of tread development width) rather than simply increasing it. This quantitative parameter optimization achieves improved mountability while avoiding excessive structural complexity. The precise parameter range balances mountability requirements with overall tire structure simplicity.
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
This configuration allows for favorable mountability on rims while reducing the vertical spring constant, improving ground contact and ride comfort without distorting the tire shape, as demonstrated by the manufacturing method and test results.
Implementation Method 1
vulcanizing the pneumatic tire in a mold formed such that the bead portions have a bead base width TBW set to range from 115% to 130% of a tread development width TDW of the tread portion
Data Source
AI summary
A pneumatic tire includes an annular tread portion extending in a tire circumferential direction, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed inward of the sidewall portions in a tire radial direction, and the sidewall portions have an average thickness set to range from 1.0 mm to 3.0 mm at a deflection region of each sidewall portion including a tire maximum width position. The bead portions have a bead base width set to range from 115% to 130% of a tread development width of the tread portion.