Pneumatic Tire Tread Contact Patch Ratio for Wear Resistance
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Solution Overview
Problem
Conventional pneumatic tires with specified tread profiles for improved uneven wear resistance still experience variations in wear patterns due to uneven tire loads, particularly in vehicles with front and rear weight imbalances, leading to rapid wear on one side of the tires.
Innovation Solution
A pneumatic tire design featuring a tread portion with a contact patch ratio of crown to shoulder contact lengths that remains consistent across varying loads, combined with a multi-radius tread profile and a robust belt layer structure, including an outer belt ply that covers at least 60% of the tread width, to distribute ground contact pressure evenly and reduce wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a specified tread profile is used to improve uneven wear resistance, then wear resistance is improved, but variation in wear resistance occurs according to tire loads
Solution Approach 1:
The tread profile is designed with multiple circular arcs having different radii of curvature to create a dynamic contact patch that adapts to varying load conditions. The multi-arc profile allows the contact patch shape to change appropriately with load, maintaining optimal wear characteristics across different loading scenarios rather than being fixed for a single condition.
Solution Approach 2:
The invention changes the geometric parameters of the tread profile by using multiple circular arcs with different radii of curvature. This parameter variation in the tread design enables the contact patch to maintain appropriate proportions between crown and shoulder contact lengths across different load conditions, resolving the contradiction between optimized wear at one load and performance at other loads.
2Strength
If the outer belt ply width is increased to improve structural support, then load distribution is improved, but manufacturing complexity increases
Solution Approach 1:
The invention optimizes the outer belt ply width as a specific parameter (at least 60% of tread width) rather than using arbitrary dimensions. This parameter optimization provides sufficient structural support for improved load distribution while avoiding excessive width that would complicate manufacturing, representing a balanced compromise between strength and ease of manufacture.
Data Source
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AI summary
A pneumatic tire includes a tread portion including a contact patch which occurs when the tire is mounted on a standard wheel rim with a standard pressure and loaded with a certain tire load at zero camber angle. The contact patch, on a respective tire load, defines a ratio Lc/Ls of a crown contact circumferential length Lc at an axial center of the contact patch to a shoulder contact circumferential length Ls at an axial location of 80% of an axial maximum width of the contact patch. The ratio Lc/Ls upon being loaded with 40% of a standard tire load is equal to or less than 125% of the ratio Lc/Ls upon being loaded with 70% of the standard tire load.