Winter Tyre Sipe Profile for Snow Grip and Stability
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Solution Overview
Problem
Winter tires with sipes experience reduced performance on snow-free road surfaces due to insufficient resistance to tangential stresses, leading to deformation and reduced contact surface, while sipes with undulating profiles provide improved grip on snow but degrade on dry or wet surfaces under extreme lateral stress conditions.
Innovation Solution
The tire features sipes with a radially outer undulating profile for enhanced grip on snow and improved block rigidity, combined with a radially inner rectilinear profile to minimize sliding and maintain stability on snow-free surfaces, and an intermediate rectilinear section for controlled block portion interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sipes with undulating profiles are provided to improve grip on snow, then lateral grip on snow-covered surface is improved, but lateral stability on snow-free surface deteriorates under extreme lateral stress
Solution Approach 1:
The sipe is divided into three distinct zones along its longitudinal extension: a first zone with an undulating profile (crests and troughs) for enhanced snow grip, a second intermediate zone with a rectilinear profile for stability, and a third zone with another undulating profile. This local differentiation allows each zone to perform its specific function optimally without compromising the overall sipe performance.
Solution Approach 2:
The sipe structure is segmented into multiple functional zones along its longitudinal extension. The first and third zones feature undulating profiles with crests and troughs for snow engagement, while the second intermediate zone has a rectilinear profile to provide structural stability. This segmentation allows the sipe to simultaneously achieve both snow grip and lateral stability.
2Force
If sipes are provided to enhance snow grip, then friction with snow is improved, but resistance to tangential stresses on snow-free surface is reduced
Solution Approach 1:
Different zones of the sipe are assigned different profile characteristics: the first and third zones have undulating profiles that maximize surface area and friction with snow, while the second intermediate zone has a rectilinear profile that provides structural strength and resistance to tangential stresses during acceleration, braking, or cornering on snow-free surfaces.
Solution Approach 2:
The sipe is segmented into functional zones where the undulating profiles in the first and third zones are optimized for snow friction, while the rectilinear profile in the second zone is optimized for structural integrity and stress resistance. This segmentation resolves the contradiction between maximizing friction and maintaining strength.
3Adaptability or versatility
If block portions are made mobile to adapt to snow surface, then adaptation to snow-covered road surface is improved, but contact surface on snow-free surface is reduced due to deformation
Solution Approach 1:
The sipe structure with its undulating profiles in the first and third zones provides mobility and adaptability to snow surface variations, while the rectilinear profile in the second intermediate zone acts as a stabilizing element that maintains block integrity and contact surface area during high-stress maneuvers on snow-free surfaces.
Solution Approach 2:
The sipe is divided into mobile zones (first and third zones with undulating profiles) that can adapt to snow surface irregularities, and a stable zone (second intermediate zone with rectilinear profile) that maintains structural integrity. This segmentation allows the block to exhibit both adaptability and stability as needed.
Data Source
AI summary
A winter tyre is described having a tread band wherein a plurality of blocks configured to obtain optimal performance both on snow-covered roads and on dry and wet roads in specific conditions of use (in particular during acceleration, braking or cornering with high power vehicles). Each of the aforementioned blocks has at least one sipe that defines two adjacent block portions in the respective block, each block portion having a respective surface facing the sipe. The surface has a radially outer portion having a profile which is substantially undulating, a radially inner portion also having a profile which is substantially undulating and an intermediate portion arranged between the radially outer portion and the radially inner portion and having a profile which is substantially rectilinear.