Variable Depth Sipe Overlap for Tire Wear and Ice Grip
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Solution Overview
Problem
Pneumatic tires with block type tread patterns for heavy duty vehicles face a trade-off between wear resistance and on-the-ice performance, as siped blocks tend to wear easily due to reduced rigidity, and decreasing sipe length compromises ice performance.
Innovation Solution
A pneumatic tire design featuring blocks with first and second variable depth sipes, where the shallow portion of one sipe overlaps with the deep main portion of another, maintaining block rigidity and wear resistance while enhancing on-the-ice performance, and tie bars in axial grooves further compensate for rigidity variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If siped blocks are provided to improve on-the-ice performance, then running performance on ice is improved, but wear resistance of the tread deteriorates
Solution Approach 1:
The sipe depth is varied locally within each sipe structure. Each sipe has a deep main portion for ice performance and a shallow portion for rigidity maintenance. This local variation in depth allows different regions of the sipe to serve different functions, resolving the contradiction between ice performance and wear resistance.
Solution Approach 2:
Each sipe is segmented into two distinct portions: a deep main portion and a shallow portion. This segmentation allows the sipe to simultaneously provide deep cuts for ice traction while maintaining structural integrity through the shallow portions, thereby improving both on-the-ice performance and wear resistance.
2Reliability
If the length and depth of sipe are increased to improve on-the-ice performance, then running performance on ice is improved, but block rigidity decreases
Solution Approach 1:
The sipe structure incorporates local quality variation by having deep main portions and shallow portions within the same sipe. The shallow portions are strategically positioned to maintain block rigidity while the deep main portions provide effective ice traction, thus resolving the contradiction between strength and ice performance.
3Duration of action of stationary object
If the length and depth of sipe are decreased to increase wear resistance, then wear resistance is improved, but on-the-ice performance deteriorates
Solution Approach 1:
The sipe is divided into deep main portions and shallow portions. The shallow portions contribute to wear resistance by reducing overall material removal, while the deep main portions maintain effective ice traction capability. This segmentation resolves the contradiction between wear resistance and ice performance.
Data Source
AI summary
A pneumatic tire comprises a tread portion provided with blocks each provided with a first variable depth sipe and a second variable depth sipe each having both axial ends opened at edges of the block on both sides thereof in the tire axial direction. In each block, a shallow portion of the first variable depth sipe overlaps, in the tire axial direction, with a deep main portion of the second variable depth sipe. an axial groove dividing the blocks is provided with a tie bar overlapping, in the tire axial direction, with the deep main portion of the adjacent variable depth sipe.