Asymmetric Tread Groove Layout for Wet Grip and Steering Stability
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Solution Overview
Problem
Existing pneumatic tires face challenges in achieving both improved wet performance and dry steering stability simultaneously, with conventional designs often prioritizing one aspect over the other.
Innovation Solution
A pneumatic tire design featuring specific groove widths and bulging road contact surfaces in the tread portion, where the groove widths of the inner center and inner shoulder main grooves are narrower and wider respectively, ensuring increased ground contact pressure and rigidity in the center region, while maintaining adequate drainage properties in the inner region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the groove width of the inner center main groove is made narrow to ensure land portion rigidity for dry steering stability, then the rigidity of the land portion in the inner region is ensured, but the drainage properties in the inner region are reduced
Solution Approach 1:
The patent applies local quality by making the groove widths different in different regions of the tread. Specifically, the inner center main groove has a narrow width (Wg3) to ensure rigidity in the center region, while the inner shoulder main groove has a wide width (Wg4) to ensure drainage in the shoulder region. This local differentiation allows each region to have the groove width optimized for its specific function.
2Reliability
If the groove width of the inner shoulder main groove is made wide to ensure drainage properties for wet performance, then the drainage properties in the inner region are ensured, but the rigidity of the land portion is reduced
Solution Approach 1:
The patent applies local quality by making the groove widths different in different regions of the tread. Specifically, the inner center main groove has a narrow width (Wg3) to ensure rigidity in the center region, while the inner shoulder main groove has a wide width (Wg4) to ensure drainage in the shoulder region. This local differentiation allows each region to have the groove width optimized for its specific function.
3Reliability
If the road contact surface is made to bulge outward to increase ground contact pressure for wet performance, then the grounding characteristics on wet road surfaces are improved, but the steering stability on dry road surfaces is reduced
Solution Approach 1:
The patent applies local quality by making the road contact surface of the land portion in the tread portion center region bulge outward, while maintaining a different profile in other regions. This localized bulging increases ground contact pressure specifically in the center region where it is needed for wet performance, while other regions maintain their original profiles to preserve steering stability.
Solution Approach 2:
The patent applies asymmetry by creating an asymmetric tread profile where the land portion in the center region has a bulging shape that protrudes outward, while the shoulder regions have a different, non-bulging profile. This asymmetric design allows the center region to optimize for wet grip while the shoulders maintain structural integrity for steering stability.
Data Source
AI summary
In a pneumatic tire, an outer second land portion, a center land portion, and an inner second land portion have a road contact surface that partially bulges toward the outer side in a tire radial direction from a reference contour line of a tread profile in the cross-sectional view in the tire meridian direction. Additionally, a groove width Wg1 of an outer shoulder main groove, a groove width Wg3 of an inner center main groove, and a groove width Wg4 of an inner shoulder main groove have a relationship of Wg3<Wg1<Wg4, 1.05≤Wg1/Wg3≤1.25, and 1.10≤Wg4/Wg3≤1.30.