Tread Gradient Design for Irregular Wear Reduction
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Solution Overview
Problem
Existing tire tread designs lack a unified approach to optimize the use of materials with different properties to minimize abnormal wear, especially in steer and trailer tires, which often develop irregular wear due to x-stresses, leading to premature tire removal.
Innovation Solution
A tire tread design featuring a gradient of properties where the system hysteresis decreases as the tread wears, while the system rigidity remains constant or decreases, achieved by using multiple layers of materials with varying hysteresis and modulus, calculated using formulas such as Hsystem=(Vkm1/Vtotal)(Hkm1)+(Vkm2/Vtot)(Hkm2), with the top layer having higher hysteresis and lower modulus than the bottom layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different tread materials with different modulus and hysteresis are used to improve abnormal wear performance, then irregular wear is reduced, but the tread design becomes complex and lacks a unified approach
Solution Approach 1:
The patent applies local quality by positioning specific tread materials with different hysteresis and modulus properties at different locations within the tread structure. The first material with greater hysteresis and lower modulus is placed in the shoulder region to reduce negative kick-out stresses, while the second material with lower hysteresis and higher modulus is placed in the center region. This localized material differentiation addresses the abnormal wear problem without requiring complete redesign of the entire tread, thus improving reliability while controlling complexity.
Solution Approach 2:
The patent employs composite materials by combining two different tread materials with distinct properties (different hysteresis and modulus values) into a single tread structure. This composite approach allows the tread to exhibit improved abnormal wear resistance through the synergistic effect of the two materials, where the first material ameliorates negative kick-out stresses and the second material provides structural support, resolving the contradiction between wear resistance and design complexity.
2Reliability
If multiple tread materials with different properties are alternated in the tread, then irregular wear performance is improved, but it is unclear which configuration maximizes the benefit
Solution Approach 1:
The patent resolves the design optimization difficulty by specifying that the first material with greater hysteresis and lower modulus should be positioned in the shoulder region where abnormal wear occurs, while the second material with lower hysteresis and higher modulus should be positioned in the center region. This localized positioning strategy provides a clear design guideline that maximizes the benefit of material differentiation without requiring complex configuration analysis, thereby improving irregular wear performance while maintaining ease of manufacture.
3Reliability
If high hysteresis material is used to change x-stresses, then abnormal wear is reduced, but rolling resistance and heat generation increase
Solution Approach 1:
The patent applies local quality by restricting the use of high hysteresis material (first material) specifically to the shoulder region where abnormal wear occurs, rather than using it throughout the entire tread. This localized application reduces negative kick-out stresses and improves abnormal wear resistance while minimizing the overall energy loss from high hysteresis material, thus balancing wear resistance with rolling resistance and heat generation concerns.
Solution Approach 2:
The patent uses composite materials to balance the trade-off between abnormal wear resistance and energy loss. The first material with greater hysteresis provides abnormal wear protection in the shoulder region, while the second material with lower hysteresis and higher modulus is used in the center region to reduce rolling resistance and heat generation. This composite structure allows the tread to exhibit improved abnormal wear resistance without the penalty of uniformly high rolling resistance, resolving the contradiction between wear resistance and energy loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively reduces abnormal wear, maintains consistent system rigidity, and balances rolling resistance and heat generation, resulting in improved tire wear performance and increased removal mileage, such as a 15% increase in removal mileage for steer truck tires.
Implementation Method 1
a gradient of properties so that a system hysteresis of that tread element decreases as the tread element wears
Implementation Method 2
a system rigidity of the tread element stays the same or decreases as the tread element wears
Data Source
AI summary
This invention relates generally to treads having a configuration and/or properties for improving or preventing irregular wear on the tread of a tire, and, more specifically, to a tire that has a tread with a gradient of properties that helps to prevent or improve irregular wear, especially suitable for tires that are free rolling such as steer or trailer tires used on trucks.