Tire Sipe With Radial Undulations and Reduced Thickness
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Solution Overview
Problem
Existing tire siping configurations struggle to simultaneously enhance traction, handling, wear performance, and reduce rolling resistance, as excessive siping can increase rolling resistance and decrease dry traction and wear life, while insufficient siping compromises wet traction and flexibility.
Innovation Solution
A tire sipe design featuring undulations in both radial and transverse directions with areas of reduced thickness, where the half pitch and amplitude of undulations vary to create a flexible tread element during contact patch entry and exit, while becoming stiff during full contact, using a sipe blade with complementary shaped sidewalls and periodic wave patterns to optimize interlocking and stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excessive siping is used to increase flexibility and traction, then wet traction and snow traction are improved, but rolling resistance increases and fuel efficiency decreases
Solution Approach 1:
The sipe is designed with varying thickness along its length, with thinner regions positioned strategically to provide flexibility and traction enhancement where needed, while thicker regions maintain structural integrity and minimize energy loss during rolling. This local variation in thickness allows different portions of the sipe to serve different functions.
Solution Approach 2:
The invention introduces undulations in the radial direction, adding a third dimension to the sipe structure. These radial undulations create a wavy pattern that allows the sipe to flex and close dynamically, reducing hysteretic losses and rolling resistance while maintaining traction benefits.
2Duration of action of moving object
If excessive siping is used to enhance flexibility during contact patch entry and exit, then wear performance is improved, but the tread element becomes too flexible during full contact, degrading dry traction
Solution Approach 1:
The sipe features localized thin regions positioned to provide flexibility during contact patch entry and exit, while other regions maintain sufficient thickness to preserve tread block rigidity during full contact. This spatial variation in thickness allows the sipe to be flexible where needed and stiff where required.
Solution Approach 2:
The undulating radial structure enables the sipe to dynamically change its effective thickness and flexibility during the tire rolling cycle. During contact patch entry and exit, the undulations allow greater flexibility for improved wear, while during full contact, the structure stabilizes to maintain rigidity for dry traction.
3Reliability
If siping is increased to provide more surface edges for adhesion, then handling and braking under wet conditions are improved, but the tread block rigidity decreases, degrading wear life
Solution Approach 1:
The sipe design incorporates localized thin regions that provide the necessary surface edges for adhesion and handling improvement, while the overall sipe structure and thicker regions maintain sufficient tread block rigidity to preserve wear life. The thin regions are strategically positioned to maximize adhesive benefits without compromising structural integrity.
Data Source
Figure 1A~1B
Figure 2~5
Figure 6
AI summary
A tire has a sipe with areas of reduced thickness. The sidewalls of the sipe may have undulations that extend both in the radial and transverse directions of the tire and the areas of reduced thickness are found in between a peak to peak or a valley to valley coincidence of the undulations. Twice the value of the amplitude of the undulations in the radial direction of the tire is greater than 95% of the value of the half pitch of those undulations. The ratio of the area of the regions of the sipe having reduced thickness to the area of the thicker regions of the sipe may meet a minimum threshold. The apparatus may also include a sipe blade that extends from a curing member that for tire molding or retreading.