Pneumatic Tire Sipe Geometry for Fatigue Crack Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pneumatic tires with narrow grooves or sipes in their tread blocks or ribs face fatigue cracks under heavy duty use, and existing solutions either compromise design parameters or increase production costs.
Innovation Solution
The tire design features sipes extending axially with an upper portion aligned radially and a lower portion inclined in the direction of rotation, reducing fatigue cracks without complex mold shapes or design parameter losses, and maintaining fuel economy and mileage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If sipes are made with perpendicular orientation to the tread block surface, then fuel economy and driving mileage are improved, but fatigue cracks propagate at the bottom of the sipes under heavy duty use
Solution Approach 1:
The sipe bottom is designed with an asymmetric inclination angle (5-45 degrees) relative to the radial direction, creating an asymmetric geometry that prevents fatigue crack propagation while maintaining the fuel economy benefits of siped treads. This asymmetric design breaks the symmetry of stress distribution at the sipe bottom.
Solution Approach 2:
The invention changes the geometric parameters of the sipe bottom by introducing an inclination angle between 5-45 degrees, transforming the traditional perpendicular (90-degree) bottom geometry into an angled configuration that reduces stress concentration and prevents crack initiation.
2Reliability
If the groove bottom radius of sipes is increased to prevent fatigue cracks, then crack propagation is reduced, but design parameters are lost and production costs increase
Solution Approach 1:
Instead of changing the radius parameter, the invention changes the angular parameter by introducing an inclination angle at the sipe bottom, achieving crack resistance through geometric angle modification rather than radius modification, thereby simplifying the mold blade design.
Solution Approach 2:
Rather than rounding the sipe bottom (adding complexity), the invention inverts the approach by creating an angled, non-rounded bottom geometry that is simpler to manufacture while achieving the same or better crack resistance效果.
3Strength
If sipes are inclined from the outer surface toward the braking force direction, then wear resistance is improved, but tread block overlap increases reducing stability and performance
Solution Approach 1:
The invention modifies the inclination parameter by limiting it to a specific range (5-45 degrees), optimizing the balance between wear resistance and tread block stability. This parameter optimization prevents excessive overlap while maintaining wear resistance benefits.
Data Source
AI summary
The present invention is directed to a pneumatic tire 1, comprising at least one pair of parallel annular beads 3; at least one carcass ply wrapped 5 around said beads 3; a tread 7; and first and second sidewalls 9 disposed between said tread 7 and one of said at least one pair of beads 3. In accordance with an embodiment of the invention, the tread comprises tread blocks 11 and/or tread ribs 12, wherein the tread blocks 11 and/or tread ribs 12 comprise sipes 13 extending essentially in an axial direction A of the tire 1, the sipes 13 consisting of an upper portion 15 essentially aligned with the radial direction R of the tire and a lower portion 17 inclined in the direction of rotation D of the tire 1.