Directional Tire Tread Blocks with Chamfers and Sipes
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Solution Overview
Problem
Existing tire treads with curved blocks for winter conditions suffer from rapid wear and inadequate balance between braking on dry ground and traction on snow-covered and wet surfaces, while maintaining performance on dry ground.
Innovation Solution
A directional tire tread with blocks featuring a central zone at 35° to 65° to the transverse direction, an edge zone at 0° to 10°, and an intermediate zone, along with median sipes and chamfers strategically placed to enhance braking on dry ground and grip on snow and wet surfaces, while maintaining engine torque transmission and reducing contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If blocks are made relatively wide to improve stiffness and braking performance on dry ground, then braking performance is improved, but the tread becomes worn rapidly
Solution Approach 1:
The block is divided into three zones with different characteristics: a central zone (35°-65°) without chamfer for durability, an intermediate zone (15°-35°) with chamfer for braking enhancement, and an edge zone (0°-15°) with chamfer for grip improvement. This local differentiation allows each zone to optimize for its specific function while balancing overall performance.
Solution Approach 2:
The block is segmented into three distinct angular zones along its curvature, with chamfers applied selectively to specific segments (intermediate and edge zones) rather than the entire block. This segmentation enables targeted modification of braking characteristics without compromising the central zone's contribution to tread life.
2Strength
If chamfers are added to blocks to improve braking on dry ground, then braking performance is improved, but the contact area with ground is reduced
Solution Approach 1:
Chamfers are applied locally only to the intermediate zone (15°-35°) and edge zone (0°-15°) of the block, while the central zone (35°-65°) maintains its full contact area. This localized application provides braking enhancement at the block edges without significantly reducing the overall contact patch.
Solution Approach 2:
Instead of applying chamfers to the entire block surface, the invention applies them partially only to specific zones where they provide maximum benefit for braking and grip while minimizing the reduction in total contact area. The central zone remains untouched to preserve contact area.
3Strength
If the density of lamellae is increased in the contact zone to improve braking on snow-covered ground, then braking on snow is improved, but the complexity of the tread design increases
Solution Approach 1:
The invention focuses complexity on specific local features (chamfers in intermediate and edge zones, median sipes) rather than increasing lamellae density across the entire contact zone. This targeted approach achieves snow braking improvement through geometric modification rather than increased structural complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution improves durability, maintains optimal braking on dry ground, and achieves excellent traction on snow and wet surfaces without compromising performance on dry ground, through the combined effects of block angles, sipes, and chamfers, which enhance friction and stiffness.
Implementation Method 1
The presence of a chamfer, in particular on the trailing edge of these zones promotes braking on dry ground
Implementation Method 2
achieves excellent traction on snow and wet surfaces without compromising performance on dry ground, through the combined effects of block angles, sipes, and chamfers, which enhance friction and stiffness
Data Source
AI summary
Tire (1) comprising a directional tread (2) comprising a plurality of blocks (5) extending continuously along an overall curvature C from one of the edges (3) towards the centre (4) of said tread, all or some of the blocks (5) of the tread comprising a median sipe (10) of length S extending along a curvature C′ substantially identical to the curvature C of the block, each block (5) comprising a central zone at an angle β1 such that 35°≤β1≤65°, an edge zone at an angle β3 such that 0°≤β3≤10°, and an intermediate zone between the central zone and the edge zone at an angle β2 allowing continuity between the three zones, at least some of the blocks (5) being designed with a block chamfer (15) provided at the trailing edge in the intermediate zone and/or the edge zone.