Overlapping Closed Sipes for Ice Traction and Turning Stability
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Solution Overview
Problem
Conventional tires with sipes in the tread portion face a trade-off between braking/driving performance and turning performance on ice, as the arrangement of sipes in the circumferential direction reduces the number of sipes per unit length, potentially impairing ice traction and braking/driving performance.
Innovation Solution
A tire design featuring closed sipes with specific geometric configurations, including inclined third sipe pieces and overlapping sipe pieces, arranged in both the axial and circumferential directions to enhance frictional force and pattern rigidity, allowing for improved braking/driving and turning performance on ice.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If sipes including a component extending in the tire circumferential direction are arranged to increase frictional force, then turning performance on ice is improved, but the number of sipes per unit length in the tire circumferential direction decreases, potentially impairing braking/driving performance on ice
Solution Approach 1:
The sipes are configured with a three-dimensional structure including inclined portions that extend in both the tire axial direction and circumferential direction. This multi-directional configuration allows the sipes to provide frictional force for turning while maintaining sufficient density in the circumferential direction for braking/driving performance.
Solution Approach 2:
Different portions of the sipes have different orientations and functions. The inclined portions provide circumferential friction for turning, while the axial components maintain density for braking. This local differentiation of sipe geometry optimizes both turning and braking/driving performance simultaneously.
2Quantity of substance
If a plurality of sipes are arranged in the tire circumferential direction to improve braking/driving performance, then the number of sipes per unit length increases, but the frictional force in the tire axial direction may be reduced
Solution Approach 1:
Each sipe is divided into multiple segments including first inclined portions, second inclined portions, and intermediate portions. This segmentation allows different segments to contribute to different functions, with the overall configuration providing both high density and sufficient axial frictional force.
Solution Approach 2:
The sipe structure combines multiple geometric elements (inclined portions, intermediate portions, and connecting elements) into a composite configuration that delivers both high sipe density and adequate frictional force in the axial direction.
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 tire exhibits excellent braking/driving and turning performance on ice due to the stable edge effect, anti-snow clogging, and increased pattern rigidity, while maintaining wear resistance and steering stability.
Implementation Method 1
The sipes exert a road surface scratching force (edge effect) by their edges, and consequently enhance performance on ice
Implementation Method 2
sipes including a component extending in the tire circumferential direction are arranged. When a plurality of such sipes are arranged in the tire circumferential direction, the number of the sipes which can be arranged per unit length in the tire circumferential direction of the land portion tends to decrease
Data Source
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AI summary
To provide a tire improved in braking/driving performance and turning performance on ice. It is a tire including a tread portion 2. The tread portion 2 includes a land portion 4. In the land portion 4, a plurality of closed sipes 8 are arranged in a tire axial direction. Each of the closed sipes 8 includes a first end 8a and a second end 8b, a first sipe piece 11 extending in the tire axial direction on a first end 8a side, a second sipe piece 12 extending in the tire axial direction on a second end 8b side, and a third sipe piece 13 inclined with respect to the tire axial direction between the first sipe piece 11 and the second sipe piece 12. The closed sipes 8 arranged in the tire axial direction overlap each other in the tire axial direction.