Pneumatic Tire Sipe Geometry for Wear Resistance
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Solution Overview
Problem
Pneumatic tires face issues with uneven wear resistance, particularly heel and toe wear in block patterns and railway wear in rib patterns, due to increased ground contact pressure and stress concentrations at sipe ends, leading to cracking and reduced durability.
Innovation Solution
Incorporating a circumferential reinforcing layer with bent sipes that have specific angles of inclination and termination points within the land portions, reducing ground contact pressure and stress concentrations, thereby enhancing wear resistance and cracking resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circumferential reinforcing layer is added to suppress radial growth and uneven wear, then uneven wear resistance is improved, but ground contact pressure increases leading to heel and toe wear in blocks and railway wear in ribs
Solution Approach 1:
The patent divides the land portions into multiple smaller segments by introducing sipes (slit-like grooves) within the land portions. This segmentation reduces the ground contact pressure concentration in each land portion, thereby suppressing heel and toe wear in blocks and railway wear in ribs, while maintaining the overall reinforcing effect of the circumferential reinforcing layer.
Solution Approach 2:
The patent applies different structural characteristics to different regions: the circumferential reinforcing layer provides overall structural support, while the sipes provide localized pressure relief in specific high-wear areas. The sipes are strategically positioned in land portions where heel and toe wear or railway wear occurs, creating local quality improvements without compromising overall tire strength.
2Reliability
If sipes are introduced to reduce ground contact pressure and suppress uneven wear, then uneven wear resistance is improved, but stress concentrations occur at sipe end points leading to cracking
Solution Approach 1:
The patent employs bent sipes with curved configurations instead of straight lines, creating two flex points (P1, P2) that act as stress distribution zones. The bent shape with specific inclination angles (α: 0°-10°, β1: 35°-55°, β2: 35°-55°) redistributes stress away from the end points (Q1, Q2), preventing stress concentration and subsequent cracking while maintaining the wear-reducing function of the sipes.
3Reliability
If sipes with straight configuration are used to reduce ground contact pressure, then uneven wear is suppressed, but stress concentrations at end points cause cracking during turning and braking
Solution Approach 1:
The patent replaces straight sipe configurations with bent configurations that incorporate flex points. This curvature design allows the sipe to flex and absorb stress during dynamic operations like turning and braking, preventing stress concentration at the end points and avoiding cracking, while still maintaining the pressure-reducing function for wear suppression.
Data Source
AI summary
In the pneumatic tire, the blocks above the circumferential reinforcing layer have at least one sipe. Also, the sipe has a bent shape, in a plan view, with two flex points P1, P2, and has a closed structure with two end points Q1, Q2 terminating within the block. Also, the angle α between the line that connects the flex points P1, P2 and the tire circumferential direction is within the range such that 0°≦α≦10°. Also, the angle β1 between the line connecting the flex point P1 and the end point Q1 and the tire circumferential direction, and the angle β2 between the line connecting the flex point P2 and the end point Q2 and the tire circumferential direction are within the range such that 35°≦β1≦55° and 35°≦β2≦55°.