Tire Tread Groove and Sipe Layout for Wear and Wet Grip
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Solution Overview
Problem
Existing tires face a challenge in balancing enhanced wear resistance with maintaining good rolling resistance and wet performance.
Innovation Solution
A tire design featuring a tread portion with circumferential grooves and land portions, including narrow and wide groove portions, and sipes across the land portions, where the maximum pitch between sipes in inner land portions is less than in outer land portions, enhancing wear resistance and wet performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the groove width is increased to improve wet performance and reduce rolling resistance, then drainage capability is enhanced, but wear resistance deteriorates due to reduced land portion width
Solution Approach 1:
The circumferential groove is segmented into two distinct portions: a narrow groove portion (first portion) and a wide groove portion (second portion). This segmentation allows the narrow portion to maintain land portion width for wear resistance, while the wide portion provides sufficient drainage capability for wet performance.
Solution Approach 2:
Different portions of the circumferential groove are assigned different widths based on local functional requirements. The narrow groove portion is positioned where wear resistance is critical, while the wide groove portion is positioned where drainage performance is prioritized, achieving local optimization of both wear resistance and wet performance.
2Duration of action of stationary object
If the groove width is reduced to improve wear resistance, then land portion width is increased, but rolling resistance performance deteriorates due to reduced drainage capability
Solution Approach 1:
The circumferential groove is divided into a narrow groove portion and a wide groove portion. The narrow portion maintains land portion integrity for wear resistance, while the wide portion ensures adequate drainage to prevent water buildup that would increase rolling resistance.
Solution Approach 2:
The groove structure applies local quality by having different widths at different positions. The narrow groove portion is located where wear resistance is paramount, while the wide groove portion is positioned to provide sufficient drainage capacity, thereby maintaining low rolling resistance.
3Ease of manufacture
If uniform sipe pitch is used across all land portions, then manufacturing is simplified, but performance is suboptimal because outer land portions require different drainage characteristics than inner land portions
Solution Approach 1:
The sipe pitch is varied according to the local requirements of different land portions. Outer land portions have smaller maximum pitch to enhance drainage in high-water-contact areas, while inner land portions have larger maximum pitch, optimizing wet performance for each specific location rather than applying a uniform design.
Data Source
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AI summary
The present invention is a tire 1 including a tread portion 2. The tread portion 2 has circumferential grooves 3 extending in a tire circumferential direction, and land portions 4 demarcated by the circumferential grooves 3. The circumferential groove 3 includes a narrow groove portion 3a having a small groove width on an outer side in a tire radial direction, and a wide portion 3b in which the groove width is great, on a side inward of the narrow groove portion 3a in the tire radial direction. The land portions 4 include a first land portion 4A and a second land portion 4B disposed inward of the first land portion 4A in the tire axial direction. The first land portion 4A and the second land portion 4B each have a plurality of sipes 5 extending across the first land portion 4A and the second land portion 4B, respectively. A maximum pitch P2 in the tire circumferential direction between the sipes 5 adjacent to each other in the tire circumferential direction in the second land portion 4B is less than a maximum pitch P1 in the tire circumferential direction between the sipes 5 adjacent to each other in the tire circumferential direction in the first land portion 4A.