Tire Tread Groove Width Variation for Wear and Drainage
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Solution Overview
Problem
Tires with continuously extending main grooves in the circumferential direction face issues with abnormal wear, reduced stiffness, and poor steering stability due to acute angles in the corner portions between the tread surface and groove walls, leading to concentrated wear and compromised wet performance over time.
Innovation Solution
The tire design features a main groove with a first portion having a constant width and a second portion with an increasing groove width towards the bottom, ensuring the corner portions remain non-acute even when new, and the second portion enhances wet performance as it wears, maintaining steering stability and reducing abnormal wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main groove has a groove wall surface that is tilted from the groove bottom toward the tread surface (conventional design), then drainage performance is improved, but the corner portion of the land becomes acute-angled causing abnormal wear and reduced steering stability
Solution Approach 1:
The main groove is segmented into three distinct portions along its depth: a first portion with constant width, a second portion with increasing width, and a third portion with decreasing width. This segmentation allows each portion to serve different functions - the first portion maintains structural integrity and prevents acute angles, while the second and third portions optimize drainage performance
Solution Approach 2:
Different cross-sectional shapes are applied to different portions of the main groove. The first portion has a constant width suitable for maintaining land portion geometry, while the second portion has an increasing width to enhance drainage. This local differentiation resolves the contradiction by optimizing each region for its specific function
2Reliability
If the corner portion of the land has an acute angle (conventional design), then the groove width increases toward the bottom improving drainage, but the corner portion receives little shearing force and causes wear concentration
Solution Approach 1:
The first portion of the main groove is designed with constant width from the outset to prevent the formation of acute angles at the corner portions. This preliminary structural design ensures that the land portions maintain proper geometry throughout their service life, distributing shear forces evenly and preventing premature wear concentration
Solution Approach 2:
The main groove exhibits asymmetric width distribution along its depth, being narrower at the top (first portion) and wider at the bottom (second portion). This asymmetric design allows the upper land portions to maintain structural integrity while the lower portions provide enhanced drainage capability
3Reliability
If the main groove extends continuously in the circumferential direction with a tilted groove wall, then wet performance is improved, but stiffness of the tread portion is reduced leading to poor steering stability
Solution Approach 1:
The continuous main groove is segmented into portions with different width characteristics. The first portion with constant width maintains tread stiffness and steering stability, while the second portion with increasing width enhances wet performance through improved water evacuation
Solution Approach 2:
The groove width parameter is changed along the depth direction of the main groove. By transitioning from constant width in the first portion to increasing width in the second portion, the design optimizes both structural stability and drainage performance
Data Source
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AI summary
Provided is a tire that can exhibit excellent wet performance over a long period of time while maintaining wear resistance and steering stability. The tire includes a tread portion 2. The tread portion 2 has at least one main groove 3 that extends continuously in a tire circumferential direction. The main groove 3 includes a first portion 6 that extends in a depth direction of the main groove 3 so as to have an almost constant groove width, and a second portion 7 that has a groove width which increases from the first portion 6 toward a groove bottom, on a transverse cross-section orthogonal to a length direction of the main groove 3.