Bi-Directional Tire Sipe Geometry for Snow Traction and Stiffness
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Solution Overview
Problem
Existing tire designs face a challenge in balancing traction on dry roadways with snow and ice, as too many sipes or slots can lead to a loss of tread block or rib stiffness, which is undesirable.
Innovation Solution
A bi-directional sipe design is implemented in the tire tread, featuring a center section with a wider radially outer portion and narrower radially inner portion, and outer sections with varying radial depths and widths, enhancing traction on snow and ice while maintaining stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sipes or slots are added to the tread to improve snow and ice traction, then traction on snow and ice is improved, but tread block stiffness is reduced
Solution Approach 1:
The sipe features varying widths and depths at different locations - wider at the radially outer portion and narrower at the radially inner portion, with different depths in axially outer and axially inner portions. This local variation optimizes snow/ice traction at the contact patch while preserving tread block stiffness in the interior regions.
Solution Approach 2:
The sipe is divided into distinct sections - a center section and outer sections - each with different dimensional characteristics. The center section has different width and depth properties compared to the outer sections, allowing each segment to serve optimized functions for traction and structural integrity.
2Reliability
If multiple sipes or slots are provided to enhance snow and ice traction, then biting edges are increased, but tread block or rib stiffness is lost
Solution Approach 1:
The sipe dimensions are carefully controlled with specific parameter variations - the radially outer portion has width WT1 while the radially inner portion has different width characteristics, and the axially outer portion has depth DB1E while the axially inner portion has depth DB1I. These parameter changes allow optimization of biting edges while maintaining structural stability.
3Reliability
If sipes with varying widths and depths are used to optimize snow and ice traction, then traction performance is improved, but manufacturing complexity increases
Solution Approach 1:
The sipe exhibits asymmetric geometry with respect to both radial and axial directions. The width varies from radially outer to radially inner portions, and the depth varies from axially outer to axially inner portions. This asymmetric design is achieved through a correspondingly asymmetric sipe blade tooling, which maintains manufacturing feasibility while achieving optimized performance.
Data Source
AI summary
In one aspect, a tire is provided, comprising: a tread portion comprising a tread rib or a tread block, a sipe included in tread rib or the tread block, wherein the sipe includes a center section located axially between opposing outer sections, and wherein the center section and each outer section include a radially outer portion and a radially inner portion, wherein the radially outer portion of each outer section has a circumferential width WT1, wherein the radially outer portion of the center section has a circumferential width WT2, wherein the circumferential width WT1 is greater than the circumferential with WT2, wherein the radially inner portion of each outer section includes an axially outer portion having a radial depth DB1E and an axially inner portion having a radial depth DB1I, and wherein the radial depth DB1E is less than the radial depth DB1I.