Asymmetric Tread Land Portions with Varying Drop Lengths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pneumatic tires with asymmetric tread patterns face challenges in achieving improved handling and stability, particularly at high speeds, due to uneven contact pressure distribution caused by widened land portions, which can lead to poor lane-changing performance and handling.
Innovation Solution
A pneumatic tire design featuring land portions with different groove area ratios on either side of the tread pattern, where one side has a larger groove area ratio and the other a smaller, with edge portions forming a protruding shape in the radial direction, and defined by specific drop lengths and curvature radii, to optimize contact pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the continuously extending land portions are widened to increase tread stiffness, then handling and stability are improved, but uneven contact pressure occurs with higher pressure in edge areas and lower pressure in inner areas
Solution Approach 1:
The patent applies local quality by creating different surface profiles in different regions of the land portion. Specifically, the inner area has a different surface profile compared to the edge areas, with the inner area having a larger radius of curvature. This local differentiation ensures that each region contributes appropriately to contact pressure distribution, with the inner area providing better pressure uniformity while edge areas maintain necessary structural support.
Solution Approach 2:
The patent utilizes curvature principles by defining specific radius of curvature values for different areas of the land portion. The inner area has a larger radius of curvature (R1) while the edge areas have smaller radii of curvature (R2). This spherical/curved surface design allows for more uniform stress distribution across the contact patch, preventing the uneven pressure concentration that occurs with flat or uniformly curved surfaces.
2Ease of operation
If the land portions are subject to uneven contact pressure, then high-speed lane change and handling performance deteriorate
Solution Approach 1:
The patent creates different surface characteristics in different zones of the land portion. The inner area (excluding edge portions) has a specific surface profile with a larger radius of curvature, while the edge areas have different profiles with smaller radii of curvature. This local differentiation optimizes the contact pressure distribution across the entire land portion, ensuring uniform pressure transmission to the road surface, which directly improves handling performance and high-speed lane change capability.
3Stability of the object's composition
If an asymmetric tread pattern is used to improve handling and stability, then groove area ratio must be optimized, but this may compromise drainage performance
Solution Approach 1:
The patent applies local quality by differentiating the surface profile of the inner area from the edge areas. The inner area has a larger radius of curvature creating a more pronounced protrusion, while edge areas have smaller radii of curvature. This local differentiation allows the asymmetric tread pattern to maintain optimized groove area ratios for handling and stability while the varied surface profiles ensure adequate drainage capability by preventing water pooling in specific high-pressure zones.
Data Source
AI summary
The pneumatic tire includes a tread pattern having a land portion sandwiched between tire circumferential grooves. A groove area ratio of the tread pattern is different between areas on opposite sides with reference to a tire center line in a tire width direction. A first side has the larger groove area ratio and a second side has the smaller groove area ratio respectively. The land portion is protruding outward in a tire radial direction and the land portion has edge portions bordering the tire circumferential grooves and formed by groove walls of the tire circumferential grooves sandwiching the land portion and a surface of the land portion. A drop length of the edge portion facing to the first side from a most protruding point of the land portion along the tire radial direction is longer than a drop length of the edge portion facing to the second side.