Tire Tread Groove Angles for Lateral Rigidity
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Solution Overview
Problem
The existing tire design with a tread portion axially divided into four land regions suffers from insufficient lateral rigidity in the outboard middle land region, leading to deterioration in steering stability on dry road surfaces.
Innovation Solution
The tire features three main grooves that axially divide the tread portion into four land regions, with the outboard middle land region having the largest axial width, incorporating inclined grooves that increase in angle and curvature to enhance rigidity and traction, while maintaining performance on snow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outboard middle land region is provided with multiple inclined grooves to improve on-snow performance, then the lateral rigidity of the outboard middle land region decreases, but this leads to deterioration in steering stability on dry road surfaces
Solution Approach 1:
The patent applies local quality by providing different groove configurations in different land regions. Specifically, the outboard middle land region is provided with first inclined grooves, second inclined grooves, and fourth inclined grooves with specific angle characteristics, while other land regions have different groove arrangements. This allows each region to be optimized for its specific function: the outboard middle land region prioritizes on-snow performance through inclined grooves, while maintaining adequate lateral rigidity through controlled groove angles and patterns.
Solution Approach 2:
The patent utilizes parameter changes by carefully controlling the groove angles of the inclined grooves. The first inclined grooves have angles of 30° to 60° relative to the tire circumferential direction, the second inclined grooves have angles of 10° to 30°, and the fourth inclined grooves have angles of 45° to 75°. By optimizing these angular parameters, the patent achieves a balance between generating sufficient shearing force on snow (requiring higher angles) and maintaining lateral rigidity (requiring lower angles).
2Stability of the object's composition
If the axial width of the outboard middle land region is increased to improve steering stability on dry road surfaces, then the space available for groove configuration is reduced, but this may compromise on-snow performance
Solution Approach 1:
The patent resolves this contradiction by utilizing multiple dimensions in groove configuration. Instead of relying solely on axial width, the patent employs grooves with varying angles (first inclined grooves at 30°-60°, second inclined grooves at 10°-30°, fourth inclined grooves at 45°-75°) and different orientations. This multi-dimensional approach allows efficient use of the available axial width while providing sufficient groove surface area for snow interaction through the combined effect of multiple groove systems with different angular characteristics.
Data Source
AI summary
A tire comprises a tread portion having outboard and inboard tread edges and provided with three main grooves to axially divide the tread portion into four land regions including a widest outboard middle land region, wherein first inclined grooves (16) extend across the entire width of the outboard middle land region; second inclined grooves (17) extend from a crown main groove and are terminated within the outboard middle land region; fourth inclined grooves (19) are connected to the second inclined grooves (17) and to the first inclined grooves on an outboard shoulder main groove side; and an angle of the first inclined groove (16) and an angle of the second inclined groove (17) with respect to the tire circumferential direction are gradually increases from the crown main groove toward the outboard tread edge.