Winter Tyre Tread Blocks with Constrained Sipes
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Solution Overview
Problem
Winter tires face a challenge in balancing grip performance on dry, wet, and snowy or icy road conditions due to the conflicting requirements of tread band configurations, where sipes improve rigidity on dry roads but can lead to excessive deformation and reduced grip on wet or snowy surfaces.
Innovation Solution
The tire features a tread band with blocks having sipes of the restrained type, configured with multiple tangentially constrained male/female-type couplings to enhance rigidity on dry roads while allowing radial displacement for improved traction on wet or snowy surfaces, combined with non-restrained sipes for optimal grip and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tread band is equipped with grooves and sipes to improve grip on wet or snowy roadbeds, then the ability to channel water and retain snow improves, but the contact surface area decreases and rigidity under shear stresses is reduced
Solution Approach 1:
The tread band is segmented into multiple blocks separated by grooves, and each block is further segmented by sipes into smaller portions. This segmentation creates multiple interfaces for water channeling and snow retention while maintaining overall structural integrity through the block configuration.
Solution Approach 2:
Different regions of the tread band are assigned different functions: grooves provide water channeling capability in specific locations, while sipes provide snow retention in block areas. The male/female coupling features are localized at sipe edges to provide targeted mechanical interlocking where needed.
2Reliability
If the blocks are provided with sipes to improve snow retention, then the road-holding on snow-covered roadbed improves, but the resistance to shear stresses decreases leading to excessive deformation
Solution Approach 1:
The sipes are configured with asymmetric male and female coupling features. The male portion protrudes into the sipe while the female portion recesses, creating an asymmetric interlocking mechanism that provides mechanical strength in specific directions while maintaining snow retention capability.
Solution Approach 2:
The male and female coupling features are pre-formed as integral parts of the block structure during tire manufacturing. This preliminary configuration ensures that the mechanical interlocking capability is already in place before the tire encounters snow or water conditions, providing immediate structural support.
3Reliability
If the tread band has a smooth surface to maximize contact area and rigidity on dry roads, then the road-holding on dry roadbed improves, but the ability to channel water and prevent aquaplaning is lost
Solution Approach 1:
The tread band structure is designed to be dynamically adaptive: on dry roads, the blocks maintain close contact with the roadbed providing large contact area and rigidity; on wet roads, the grooves and sipes open up to channel water away, preventing aquaplaning while the male/female couplings maintain block integrity.
Data Source
AI summary
A tire includes: a tread band on which is defined a radially outer tread surface, a first plurality of blocks provided on the tread band, and at least a first sipe of the restrained type extending on at least one block of the first plurality in a substantially axial direction defined on the tread band. The first sipe is configured so as to define, between a first and a second block portion divided by the first sipe, at least two separate and distinct couplings of the male/female type, such as to prevent the mutual displacement of the block portions in any direction which, at the block, is substantially tangential to the tread surface, and such as to permit mutual displacement of the block portions in a direction incident to the tread surface. In addition, the first sipe does not intersect any other sipe of the restrained type within the block.