Pneumatic Tire Land Portion Arc Radius and Void Ratio
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Solution Overview
Problem
Pneumatic tires with uneven ground contact pressures due to non-uniform distribution of lateral grooves and sipes on land portions suffer from deteriorated road-hugging properties and uneven wear.
Innovation Solution
The tire features a tread portion with main grooves and land portions, where the land portions have arc-shaped ground contact areas with varying void ratios, allowing for balanced rigidity and uniformized ground contact pressure by adjusting the surface area ratios of depressed portions between main grooves, thereby enhancing road-hugging properties and restricting uneven wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lateral grooves and sipes are provided on land portions, then drainage performance and flexibility are improved, but ground contact pressure becomes non-uniform causing deteriorated road-hugging property and uneven wear
Solution Approach 1:
The patent applies local quality by configuring each land portion with a specific void ratio (a/A) that corresponds to its position and function. Different land portions have different void ratios to balance flexibility for drainage with sufficient ground contact pressure. The ground contact area of each land portion is designed with an arc shape and specific radius of curvature based on its void ratio, creating locally optimized contact characteristics that ensure uniform overall ground contact pressure while maintaining drainage capability.
2Reliability
If ground contact areas of land portions are protruded radially outward, then road-hugging property is improved, but uneven wear occurs due to non-uniform ground contact pressure
Solution Approach 1:
The patent applies parameter changes by systematically varying the void ratio (a/A) of different land portions and corresponding arc radius of curvature values to achieve uniform ground contact pressure distribution. Land portions with larger void ratios are configured with smaller arc radii of curvature, and vice versa. This parametric optimization ensures that all land portions make uniform contact with the road surface, improving road-hugging property while preventing uneven wear and extending tire service life.
3Adaptability or versatility
If land portions have different void ratios, then flexibility and drainage are enhanced, but ground contact pressure distribution becomes non-uniform
Solution Approach 1:
The patent applies asymmetry by intentionally creating asymmetric void ratio distributions across different land portions, with each land portion having a unique void ratio (a/A) value. This asymmetric configuration is compensated by adjusting the arc radius of curvature of each land portion's ground contact area. The asymmetric void ratios provide localized flexibility and drainage, while the corresponding arc radius adjustments ensure symmetric uniform ground contact pressure distribution across the entire tread.
Data Source
AI summary
A pneumatic tire includes: a tread portion; three or more main grooves provided on the tread portion at intervals in a tire width direction so as to extend in a tire circumferential direction; and a plurality of land portions partitioned between the main grooves adjacent to each other in the tire width direction, wherein the plurality of land portions include: ground contact areas having an arc shape in cross section in the tire width direction; and depressed portions opening to the ground contact areas, and the land portion having a larger ratio of opening surface area a of the depressed portions opening in the area between the main grooves adjacent to each other in the tire width direction with respect to surface area A of the area (a/A) has an arc-shaped ground contact area with a cross section in the tire width direction having a smaller radius of curvature.