Pneumatic Tire Land Portion Width Ratio for Wear Resistance
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Solution Overview
Problem
Pneumatic tires face issues with uneven wear resistance, particularly in regions where the circumferential reinforcing layer is disposed, leading to uneven wear between land portions.
Innovation Solution
The tire design includes a belt layer with a circumferential reinforcing layer and specific width and stiffness relationships between land portions, ensuring a wider first land portion at the center and a narrower second land portion at the end of the reinforcing layer, along with varying groove wall angles to maintain appropriate stiffness differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a circumferential reinforcing layer is provided in the belt layer to suppress tire radial growth, then tire radial growth is suppressed, but uneven wear occurs in the land portions above the circumferential reinforcing layer
Solution Approach 1:
The patent applies local quality by creating different land portion widths at different locations. Specifically, the first land portion (above the circumferential reinforcing layer) is made narrower than the second land portion (outside the circumferential reinforcing layer). This local differentiation in geometry compensates for the stiffness difference caused by the circumferential reinforcing layer, thereby suppressing uneven wear while maintaining radial growth suppression.
2Reliability
If the first land portion is made wider than the second land portion, then uneven wear in the first land portion is suppressed, but the stiffness difference between land portions becomes excessive
Solution Approach 1:
The patent applies parameter changes by precisely controlling the width ratio between the first and second land portions within a specific range (0.85 ≤ W1/W2 < 1.0). This quantitative parameter control ensures that the stiffness difference is optimized - narrow enough to suppress uneven wear but not so narrow as to create excessive stiffness difference that would harm other performance characteristics.
3Stability of the object's composition
If the circumferential reinforcing layer extends to the edge of the tread portion, then tire radial growth is maximally suppressed, but uneven wear resistance deteriorates due to stiffness concentration
Solution Approach 1:
The patent applies local quality by creating a transition zone where the circumferential reinforcing layer does not extend to the very edge of the tread portion. The second land portion outside the circumferential reinforcing layer is made wider to gradually transition the stiffness distribution, preventing concentration of stiffness at the edge while maintaining overall radial growth suppression.
Data Source
AI summary
The pneumatic tire includes a belt layer having a circumferential reinforcing layer. Additionally, the pneumatic tire includes a plurality of circumferential main grooves, and a plurality of land portions partitioned by the circumferential main grooves in a tread portion. The width W1 of the land portion on a tire equatorial plane, and the width W2 of the second land portion at an end portion of the circumferential reinforcing layer have a relationship such that 1.05≦W1/W2≦1.30.