Evolving Tread Sipes for Snow Grip Through Tire Wear
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Solution Overview
Problem
Snow tires lose grip effectiveness as the tread wears down due to decreased slenderness of rubber blades, which reduces the biting effect on snow-covered surfaces.
Innovation Solution
A tire design featuring a tread with complex sipes and grooves formed in a first rubber composition, and a second layer of material extending laterally beyond the complex sipes, which appears at advanced wear levels to enhance grip on snow and wet surfaces, using different rubber compositions for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tread is new with high slenderness ratio blades, then the biting effect on snow is improved, but the grip deteriorates as the tread wears and blade height decreases
Solution Approach 1:
The sipe geometry dynamically changes with tread wear. Initially, the sipes have narrow openings providing high slenderness ratio blades for biting into snow. As the tread wears, the sipe openings widen, transforming the structure to maintain effective blade geometry and grip performance throughout the tread's service life.
Solution Approach 2:
The patent changes the geometric parameters of the sipes - specifically the opening width and blade configuration - to adapt to different wear stages. The sipe design includes variable width openings that allow the rubber blades to maintain optimal slenderness ratio even as the overall tread thickness decreases during wear.
2Reliability
If complex sipes with variable width are used, then grip is maintained at advanced wear levels, but the device complexity increases
Solution Approach 1:
The sipes feature locally varied geometry with different opening widths at different positions and depths. This local quality variation allows specific regions of the sipe to perform different functions - narrower regions for biting action and wider regions for snow/water reservoir formation - thereby maintaining grip without requiring complete structural redesign.
Solution Approach 2:
The patent introduces a third dimension to the sipe structure by varying the opening width through the depth of the sipe, not just at the surface. This creates a three-dimensional complex geometry that allows the same sipe structure to provide both initial biting capability and advanced-wear grip maintenance through differential width zones.
Data Source
AI summary
A tire having a tread with a plurality of blocks 12 provided with at least one sipe 22 extending from the contact face of said block, and having a width that can vary in the direction of its depth, and known as a complex sipe. The tread has a first layer of material 38 and at least one second layer of material 40 radially on the inside of the first layer, the first layer being formed in a first rubber composition and the second layer being formed in a second rubber composition different from the first composition. The complex sipe 22 and the grooves separating the blocks are formed entirely in the first layer of material 38. Laterally on each side of the complex sipe, the second layer of material 40 extends, when viewed in transverse section in the block, beyond the bottom 30 of the complex sipe in the direction of the contact face of the block.