Tire Tread Profile With Variable Stiffness Rows
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Solution Overview
Problem
Conventional winter tread profiles of pneumatic vehicle tires often result in non-uniform axial abrasion distribution, making it challenging to achieve a uniform wear pattern without compromising other desired properties.
Innovation Solution
The design features a tread profile with axially adjacent tread block rows extending over the entire circumference, where the outer tread block rows have greater average circumferential stiffness than the inner rows, and the use of transverse grooves decouples the tread block rows, reducing abrasion loads on middle rows and increasing loads on outer rows, thereby achieving a uniform wear pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional winter tread profiles are used with uniform tread block rows, then the tire structure is simple and easy to manufacture, but the wear pattern becomes non-uniform along the axial direction
Solution Approach 1:
The patent applies local quality by differentiating the circumferential stiffness of tread block rows based on their axial position. Outer tread block rows are designed with greater circumferential stiffness while inner rows have lower stiffness, creating localized property variations that compensate for non-uniform wear patterns and achieve more uniform wear distribution across the tread width.
Solution Approach 2:
The patent employs asymmetry by creating an asymmetric stiffness distribution across the tread profile. The circumferential stiffness varies asymmetrically from outer to inner tread block rows, with outer rows being stiffer and inner rows being more compliant. This asymmetric design counteracts the natural tendency toward non-uniform wear and achieves improved wear uniformity.
2Manufacturing precision
If outer tread block rows are made with greater circumferential stiffness, then wear uniformity is improved, but the outer rows experience increased abrasion loads
Solution Approach 1:
The patent converts the harmful effect of high abrasion loads on outer tread block rows into a beneficial outcome. By designing outer rows with greater circumferential stiffness, they are intentionally subjected to higher abrasion loads that serve to even out the overall wear pattern across the tread, transforming the potential harm into a mechanism for achieving uniform wear distribution.
3Manufacturing precision
If transverse grooves are used to decouple tread block rows, then wear pattern is improved, but the structural integrity may be compromised
Solution Approach 1:
The patent applies segmentation by introducing transverse grooves that divide the tread block rows into separate, decoupled segments. These grooves create independent motion zones for adjacent tread block rows, allowing them to move independently during tire operation. This segmentation reduces the coupling of shear stresses between rows and improves wear uniformity while maintaining sufficient structural integrity through the overall tread design.
Data Source
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AI summary
A tread profile has five arrays (19-22,24) of tread blocks (35-39) distributed over the entire tire tread width. The tread blocks are separated from each other by intersecting axial grooves (25-29) and circumferential grooves (12,16-18). The average rigidities of the tread block arrays (19,24) at the tire outside and inside edges or shoulders are greater than the average rigidities of the arrays (20-22) between the outside and inside edges. An independent claim is also included for a tire tread.