Tyre Tread Layout Balancing Snow Grip and Band Rigidity
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Solution Overview
Problem
All season tyres for high or ultra high performance cars face conflicting requirements of ensuring long mileage, high performance levels in straight running and cornering, braking and traction, low noise, and maintaining safety on wet and snowy roads while avoiding performance decay at high speeds and noise generation.
Innovation Solution
A tyre design with a central region and two shoulder regions, featuring a uniform distribution of grooves and sipes to maintain tread band stiffness, minimizing intersections, and optimizing the void-to-rubber ratio for balanced performance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dense siping and wide deep grooves are provided in the tread band, then the tyre provides better grip on snow-covered roads and improved drainage on wet ground, but the rigidity of the tread band is reduced causing performance decay at high speed
Solution Approach 1:
The tread band is divided into different regions with different groove and sipe densities. The central region has a first void-to-rubber ratio optimized for high-speed performance, while the shoulder regions have a second void-to-rubber ratio optimized for snow and wet ground grip. This local differentiation allows each region to perform its specific function without compromising overall tread band rigidity.
Solution Approach 2:
The tread band is segmented into a central region and shoulder regions with distinct groove and sipe patterns. The central region contains grooves extending in the circumferential direction with specific spacing, while the shoulder regions contain additional grooves extending in the axial direction. This segmentation allows the central region to maintain rigidity for high-speed stability while the shoulder regions provide enhanced grip in adverse conditions.
2Reliability
If a dense siping and wide deep grooves are provided in the tread band, then the drainage capability on wet ground is improved, but the tyre generates more noise and reduces mileage
Solution Approach 1:
Different regions of the tread band are assigned different groove densities and patterns. The central region has optimized groove spacing for reduced noise and improved mileage, while the shoulder regions have enhanced groove density for superior drainage capability. This local differentiation allows the tyre to drain water effectively without generating excessive noise across the entire tread.
3Strength
If the void-to-rubber ratio is significantly reduced to improve performance and grip, then the tyre provides excellent performance on track, but the safety parameters are lowered in wet and snowy conditions
Solution Approach 1:
The tread band is divided into central and shoulder regions with different void-to-rubber ratios. The central region has a lower void-to-rubber ratio for optimal track performance and grip, while the shoulder regions have a higher void-to-rubber ratio for improved safety in wet and snowy conditions. This segmentation allows the tyre to maintain high performance on dry surfaces while ensuring safety in adverse weather.
4Duration of action of moving object
If a high number of grooves and recesses are provided to achieve long mileage, then the tyre provides more rubber to the ground, but the draining features and safety on wet and snowy roads are compromised
Solution Approach 1:
The tread band features different groove densities in different regions. The central region has optimized groove spacing that balances mileage durability with adequate drainage, while the shoulder regions have enhanced groove density specifically for maintaining safety in wet and snowy conditions. This local differentiation allows the tyre to achieve long mileage without compromising draining features or safety.
Data Source
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AI summary
Car tyre (100) having a tread band (7) comprising a central region (L1) and two shoulder regions (L2, L3); the central region (L1) having a plurality of ribs (8, 9, 10), wherein a first rib (8) with a plurality of first transverse grooves (15) comprising a substantially straight first segment (15'), inclined relative to a direction parallel to said equatorial plane (X-X) so as to form an angle Θ smaller than or equal to 70°, a substantially straight counter-inclined second segment (15") and a curved connecting segment (15'") extending between said first segment (15') and said second segment (15"); - the first rib (8) further comprising first straight sipes (21) located in the first rib (8) between said first transverse grooves (15) and extending over at least 60% of the width of said first rib (8); the first sipes (21) forming with said equatorial plane (X-X) an angle Θ' preferably equal to the angle Θ of the first segment (15') of the first transverse grooves (15).