Tire Tread Narrow Groove Layout for Wet Braking and Low Rolling Resistance
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Solution Overview
Problem
Heavy duty tires face challenges in achieving compatible low rolling resistance, uneven wear resistance, and wet braking performance, with existing technologies often compromising on one aspect to improve another.
Innovation Solution
A tire design featuring a circumferential narrow groove in the tread portion center region with chamfered land portions, reducing groove area for lower rolling resistance and enhancing wet braking performance by enlarging the groove volume and ensuring the rigidity of the tire, while suppressing uneven wear through specific chamfered portion lengths and shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a main groove is provided in the tread portion center region, then wet braking performance is improved, but rolling resistance increases and uneven wear resistance deteriorates
Solution Approach 1:
The patent applies local quality by providing chamfered portions only at specific locations (edge portions of land portions adjacent to the circumferential narrow groove) rather than uniformly across the entire tread. This localized modification enlarges groove volume where needed for wet braking performance while maintaining smaller groove area overall to reduce rolling resistance and prevent uneven wear.
2Loss of energy
If groove area is reduced to lower rolling resistance, then rolling resistance decreases, but wet braking performance deteriorates
Solution Approach 1:
The patent transitions from considering only groove area (two-dimensional parameter) to incorporating groove volume (three-dimensional parameter) through the addition of chamfered portions. This dimensional change allows the groove to have smaller area (reducing rolling resistance) while simultaneously having sufficient volume (maintaining wet braking performance) through increased depth at critical locations.
3Reliability
If groove volume is enlarged to improve wet braking performance, then wet braking performance improves, but rolling resistance increases
Solution Approach 1:
The chamfered portions are strategically placed only at edge portions of land portions adjacent to the circumferential narrow groove, concentrating the groove volume enlargement where it most effectively improves wet braking performance. This localized approach minimizes the overall groove area, thereby reducing rolling resistance while still achieving sufficient groove volume for wet braking.
Data Source
AI summary
A tire includes a circumferential narrow groove disposed in a tread portion center region and having a groove width of 0.5 mm or more and 3.0 mm or less, and a first land portion defined by the circumferential narrow groove and a second land portion located further on a tire equatorial plane side than the first land portion and adjacent to the first land portion. Additionally, the first and second land portions include chamfered portions, respectively in edge portions on the circumferential narrow groove side. Additionally, a circumferential length L33 of the chamfered portion of the second land portion has the relationship L33<L24 with respect to a circumferential length L24 of the chamfered portion of the first land portion.