Asymmetric Tire Tread Lug Geometry for Dry-Wet Steering Stability
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Solution Overview
Problem
Pneumatic tires face a trade-off between steering stability on dry and wet road surfaces, with increased lug grooves improving dry stability but reducing wet stability, and vice versa, making it difficult to achieve both simultaneously.
Innovation Solution
The tire design features four main grooves with specific lug groove configurations, including curved lug grooves in the shoulder and intermediate land portions, non-overlapping lug grooves in the intermediate land portion, and a zigzag center main groove, which enhance both dry and wet road stability by maintaining rigidity and drainage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of lug grooves in the tread portion is increased, then drainage performance is improved, but steering stability performance on dry road surfaces is reduced
Solution Approach 1:
The patent applies local quality by providing lug grooves only in the shoulder land portion and intermediate land portion on the vehicle outer side, while omitting them from the vehicle inner side. This asymmetric configuration allows the outer side to drain water effectively while the inner side maintains higher rigidity for steering stability, thus resolving the contradiction between drainage performance and dry road steering stability.
Solution Approach 2:
The patent segments the tread portion into different functional zones: the shoulder land portion and intermediate land portion on the vehicle outer side contain lug grooves for drainage, while the vehicle inner side maintains continuous land portions for stability. This segmentation allows each zone to optimize its function independently, achieving both drainage performance and steering stability.
2Stability of the object's composition
If the number of lug grooves in the tread portion is reduced, then steering stability performance on dry road surfaces is improved, but drainage performance is deteriorated
Solution Approach 1:
The patent concentrates lug grooves in specific local areas (shoulder and intermediate land portions on the vehicle outer side) rather than distributing them uniformly. This localized approach provides sufficient drainage capability in water-prone outer regions while preserving land portion continuity and rigidity in the vehicle inner side, thus maintaining steering stability on dry roads.
Solution Approach 2:
The patent applies partial action by providing lug grooves in only half of the tread portion (vehicle outer side) rather than the entire circumference. This partial configuration achieves adequate drainage performance for the vehicle's operating conditions while minimizing the impact on overall steering stability.
Data Source
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AI summary
Provided is a pneumatic tire capable of achieving both steering stability performance on dry road surfaces and steering stability performance on wet road surfaces in a compatible manner. An outer side intermediate land portion (23) and an outer side shoulder land portion (25) each have a plurality of lug grooves (31, 32) extending in a tire width direction while being curved; one end of each of the plurality of lug grooves (32) in the outer side shoulder land portion (25) reaches at least a ground contact edge, while the other end terminates in the outer side shoulder land portion (25); one end of each of the plurality of lug grooves (31) in the outer side intermediate land portion (23) communicates with a shoulder main groove (14) and the other end terminates in the outer side intermediate land portion (23); an opening end (31A) of each of the plurality of lug grooves (31) in the outer side intermediate land portion (23) with respect to the shoulder main groove (14) exist on an extension line of each of the plurality of lug grooves (32) in the outer side shoulder land portion (25); and a pair of the plurality of lug grooves (31) adjacent in the outer side intermediate land portion (23) are disposed so as not to overlap each other in the tire circumferential direction.