Pneumatic Tire Groove Design for Steering Stability and Wet Performance
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Solution Overview
Problem
Pneumatic tires face challenges in achieving both steering stability and wet performance simultaneously due to the degradation of rigidity in land portions where grooves are formed, leading to stress concentration and crack formation, as well as compromised drainage properties when trying to enhance rigidity or drainage.
Innovation Solution
The design incorporates a combination of main grooves, shoulder lug grooves, and narrow grooves with specific depth and width relationships, including raised bottom portions in shoulder lug grooves and narrow grooves that connect across ground contact edges, optimizing groove depths and angles to balance rigidity and drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If raised bottom portions are formed in lug grooves defining shoulder blocks to improve steering stability, then block rigidity is improved, but drainage properties are degraded
Solution Approach 1:
The patent applies local quality by forming raised bottom portions only in specific regions of the lug grooves (defining shoulder blocks) rather than uniformly across all grooves. This localized approach allows the shoulder blocks to have enhanced rigidity for steering stability while other regions maintain adequate drainage properties. The raised bottom portions are positioned strategically to provide structural support where needed without compromising overall water drainage capability.
2Strength
If significant bottom raising is performed to secure block rigidity, then steering stability is improved, but wet performance is degraded
Solution Approach 1:
The patent implements local quality by limiting raised bottom portions to specific lug grooves that define shoulder blocks, rather than applying significant bottom raising across the entire tread. This selective approach ensures that block rigidity is enhanced in critical steering regions while maintaining adequate groove depth and drainage properties in other areas, thereby preserving wet performance.
Solution Approach 2:
The patent applies partial action by performing bottom raising only to the extent necessary in specific regions. Rather than uniformly raising the bottom of all grooves excessively, the invention raises bottom portions only in the lug grooves defining shoulder blocks, and only to the degree needed to improve steering stability without compromising wet performance in other critical drainage areas.
3Reliability
If grooves are formed in land portions for water drainage, then wet performance is improved, but rigidity of land portions is degraded
Solution Approach 1:
The patent applies local quality by creating raised bottom portions in specific lug grooves to locally enhance land portion rigidity where shoulder blocks are defined. This localized reinforcement compensates for the rigidity reduction caused by groove formation in critical steering regions, while maintaining adequate drainage properties in other areas where grooves are present.
Data Source
AI summary
A pneumatic tire includes shoulder lug grooves and narrow grooves. The shoulder lug grooves are positioned outward in a width direction with respect outermost main grooves. The narrow grooves are positioned outward in the width direction with respect to the outermost main grooves, are formed in spaces between the shoulder lug grooves that are adjacent to each other in the tire circumferential direction, and have both ends connected to the shoulder lug grooves. The narrow grooves are formed across the ground contact edges. A relationship W≥(D1×0.8) is satisfied, where W indicates a distance between the ground contact surface inner end portions and the outermost main grooves in the tire width direction and D1 indicates a groove depth of the outermost main grooves.