Shoulder Sipe Tire Tread Layout for Low Rolling Resistance
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Solution Overview
Problem
Existing tires face a challenge in reducing rolling resistance without compromising wet road surface grip performance.
Innovation Solution
A tire design featuring circumferential main grooves and circumferential sipes that divide the tread into multiple land portions, with a circumferential sipe located between the shoulder circumferential main groove and the end of the outer layer, maintaining a specific ratio and groove width to suppress compressive strain in the shoulder land portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the tread structure is simplified to reduce rolling resistance, then rolling resistance is reduced, but wet road surface grip performance deteriorates
Solution Approach 1:
The tread is segmented into multiple land portions by circumferential main grooves, and further segmented by circumferential sipes within each land portion. This segmentation allows water to be channeled away through the main grooves while the sipes provide additional water evacuation paths and maintain grip by creating biting edges, thus reducing rolling resistance without compromising wet grip performance.
Solution Approach 2:
Different regions of the tread are given different characteristics: the circumferential main grooves provide water evacuation channels, while the circumferential sipes in the shoulder land portions provide localized water evacuation and grip enhancement. The sipes are specifically positioned at ratios of 10-95% from the shoulder circumferential main groove to optimize their effectiveness in reducing compressive strain while maintaining wet grip.
2Loss of energy
If circumferential sipes are added to reduce compressive strain, then rolling resistance is reduced, but the complexity of the tread structure increases
Solution Approach 1:
The circumferential sipes segment the land portions into smaller sub-portions, creating multiple small channels for water evacuation. This segmentation reduces the compressive strain on any single portion of the tread while maintaining overall structural integrity, thereby reducing rolling resistance without requiring complete redesign of the entire tread structure.
Solution Approach 2:
Instead of adding numerous sipes throughout the entire tread, the invention applies sipes selectively in specific land portions at specific positions (10-95% ratio from the shoulder circumferential main groove). This partial action approach achieves the rolling resistance reduction goal by targeting the most critical areas where compressive strain occurs, without unnecessarily increasing overall tread complexity.
Data Source
Figure 1
Figure 2(A)~2(C)
Figure 3
AI summary
A tire 2 includes a tread 4 and a belt 14 including an inner layer 38 and an outer layer 40. Each end of the outer layer 40 is located axially inward of an end of the inner layer 38. A circumferential sipe 50 is formed on each shoulder land portion 52s so as to continuously extend in a circumferential direction, has a smaller groove width than a shoulder circumferential main groove 48s, and is located between the shoulder circumferential main groove 48s and an end of the outer layer 40 in an axial direction. The ratio of a distance in the axial direction from the shoulder circumferential main groove 48s to the circumferential sipe 50 to a distance in the axial direction from the shoulder circumferential main groove 48s to the end of the outer layer 40 is not less than 10% and not greater than 95%.