Heavy-Duty Tire Tread Relief Angles for Wear Reduction
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Solution Overview
Problem
Radial tires for heavy construction vehicles experience rapid wear due to high mechanical stress from operating in quarries, where tires are subjected to abrasive tracks and significant load variations during laden and unladen cycles, leading to increased operating costs.
Innovation Solution
The tire design features a tread pattern with a first median portion and two lateral portions, each with specific relief angles that generate overall coupling forces aligned with the vehicle's movement direction under both engine torque and braking torque, reducing slip and wear by distributing load and stress effectively across the tread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional tread patterns are used, then manufacturing simplicity is maintained, but tread wear rate increases rapidly under high mechanical stress
Solution Approach 1:
The tread is divided into multiple circumferential portions (first, second, third, fourth portions) with different relief angle configurations. Each portion is further segmented into elements in relief separated by cuts, creating a complex segmented structure that redistributes mechanical stress and reduces tread wear rate under high load conditions.
Solution Approach 2:
Different circumferential portions of the tread are assigned different local qualities through varying relief angles. The first and third portions have first relief angles while the second and fourth portions have second relief angles, creating localized variations that optimize stress distribution and reduce wear in specific high-stress zones.
2Force
If higher load capacity is designed into the tire, then vehicle payload capability is improved, but mechanical stress on the tread increases leading to faster wear
Solution Approach 1:
The tread pattern incorporates dynamic stress redistribution through its multi-portion structure with varying relief angles. Under high load conditions, the different relief angles cause elements in relief to deform and redistribute stresses dynamically across the contact patch, preventing concentration of stress that would accelerate wear while maintaining high load capacity.
Solution Approach 2:
The invention changes the geometric parameters of the tread elements by specifying different relief angles for different circumferential portions. This parameter variation allows the tread to adapt its stress distribution characteristics under high load, reducing wear rate while maintaining the necessary load-bearing capacity for heavy vehicles.
3Loss of substance
If tread elements with uniform relief angles are used, then manufacturing precision is simplified, but slip and wear are increased under varying load conditions
Solution Approach 1:
The circumferential tread is segmented into distinct portions with different relief angle specifications. This segmentation allows precise control over the relief angles in each portion, creating a manufacturing blueprint that balances precision requirements with wear reduction performance under varying load and slip conditions.
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 reduces tread wear by minimizing slip and contact pressure, resulting in lower operational costs and extended tire life through optimized force distribution and stress management.
Implementation Method 1
A coupling force is understood to be a circumferential force, tangent to the tread, generated by the applied load, caused by the Poisson effect on the elements in relief.
Data Source
AI summary
Tread (2) of a radial tire for a heavy vehicle. The tire alternatingly rolls in laden and unladen states on descent and ascent, respectively. Tread (2) has total width WT and comprises first median portion (21) having median width Wc, where 0.2WT≤Wc≤0.5WT. Tread (2) is axially delimited by second and third lateral portions (22, 23) having respective lateral widths (WS2, WS3) at least equal to 25% and at most equal to 40% of total width WT. Angle A51 of leading face (51) of every element in relief (31) of first median portion (21) is strictly greater than angle A61 of trailing face (61) of said element in relief (31). Angle (A52, A53) of leading face (52, 53) of every element in relief (32, 33) of each of the second and third lateral portions (22, 23) is strictly less than angle (A62, A63) of trailing face (62, 63) of said element in relief (32, 33).