Concave Tread Profile for Stable Rear Tire Footprints
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Solution Overview
Problem
High-performance tires for rear axle applications face challenges in maintaining tire footprint shape and load distribution during dynamic conditions and high speeds, leading to issues like rear axle oversteering and transitory zigzag motion due to loss of grip.
Innovation Solution
A tire design featuring a tread surface with a concave shape in the central portion, optimized without additional reinforcement materials, and a tire mold producing this concave shape to enhance footprint stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a third overlay layer is added in the center of the footprint to maintain footprint shape and load distribution, then footprint stability is improved, but tire weight and production costs increase
Solution Approach 1:
The patent applies curvature by forming a concave shape in the central portion of the tread surface. This geometric modification changes the contact patch geometry during tire deformation, allowing the footprint to maintain its shape and load distribution without adding material layers. The concave profile (curved surface) redistributes contact pressure more effectively than a flat surface would alone.
2Stability of the object's composition
If a third overlay layer is added in the center of the footprint to maintain footprint shape and load distribution, then footprint stability is improved, but production cycle time and costs increase
Solution Approach 1:
The concave shape is formed as an integral part of the tread molding process using a mold with a corresponding convex surface. This eliminates the need for separate overlay layer application steps, reducing production cycle time while achieving the same footprint stability effect.
3Reliability
If the footprint area is prevented from deforming to maintain grip, then cornering stability is improved, but tire complexity and manufacturing difficulty increase
Solution Approach 1:
The concave tread surface profile provides inherent geometric control over footprint deformation characteristics. This passive geometric solution prevents excessive footprint area deformation during cornering without requiring active control systems or complex internal structures, thereby maintaining cornering grip while limiting tire structural complexity.
4Stability of the object's composition
If additional reinforcement materials are added to maintain footprint shape, then footprint stability is improved, but tire weight increases
Solution Approach 1:
The patent uses the concave surface geometry to achieve footprint shape stability through mechanical advantage of the curved profile rather than through additional reinforcement materials. The curved surface distributes and manages contact pressures more effectively, providing the needed stability without the weight penalty of extra materials.
Data Source
Figure 1~2
Figure 3~4
AI summary
A tire (1) is disclosed comprising a tread portion (9) that is divided in the tire axial width direction between a first shoulder portion (13), a central portion (15) and a second shoulder portion (17). The radially outer surface of the tread portion (9) has a profile with a concave shape over at least a part of its axial width. Also disclosed is a mold (27) to produce such a tire (1) and a method of producing such a tire (1).