Studless Tire Tread Layout Balancing Sipe Density and Block Rigidity
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Solution Overview
Problem
Conventional studless tires face challenges in balancing performance on ice and snow roads with dry roads, as increasing sipe density improves ice performance but deteriorates dry road wear resistance and block rigidity, leading to reduced traction and shorter tire life.
Innovation Solution
The tire design features a larger sipe interval to increase block rigidity, combined with a shorter pitch length to enhance the number of blocks and edge effect, using foamed rubber with a specific elastic modulus range to improve ground contact area and wear resistance, while maintaining on-ice performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of sipes formed in the land portion block is increased, then the on-ice performance is improved, but the block rigidity is deteriorated and wear resistant performance on dry road surface is largely deteriorated
Solution Approach 1:
The patent applies local quality by differentiating the sipe configuration across different land portion blocks. Specifically, the first land portion blocks have a first number of sipes while the second land portion blocks have a second number of sipes, where the first number is greater than the second number. This local differentiation allows the first blocks to provide superior on-ice performance while the second blocks maintain higher block rigidity and wear resistance on dry roads, thus resolving the contradiction between on-ice performance and block rigidity.
2Reliability
If the number of sipes formed in the land portion block is increased, then the edge component that scratches the road surface is increased, but the tire lifetime is shortened due to increased wear
Solution Approach 1:
The patent implements local quality by creating spatial differentiation in sipe density across the tread pattern. The first land portion blocks contain a higher number of sipes to maximize edge component and braking performance on ice, while the second land portion blocks contain fewer sipes to maintain structural integrity and reduce wear. This localized optimization ensures that high wear areas have fewer sipes (extending tire life) while high-performance areas have more sipes (improving braking on ice).
3Strength
If the pitch length defined by a repeating unit of a shape of the tread is made long, then the rigidity of the land portion block is increased, but the number of pitches or land portion blocks within the ground contact length is decreased
Solution Approach 1:
The patent applies segmentation by dividing the tread pattern into multiple discrete land portion blocks with different sipe configurations. Instead of using a single pitch length for all blocks, the invention segments the blocks into at least two types: first land portion blocks with higher sipe counts and second land portion blocks with lower sipe counts. This segmentation allows optimization of each block type's pitch length independently, maintaining overall block rigidity while ensuring sufficient number of blocks remain in ground contact at any given time.
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
This configuration enhances braking performance on ice, maintains wear resistance on dry roads, and extends tire life by balancing block rigidity and edge effect, ensuring high performance on both ice and dry surfaces.
Implementation Method 1
using foamed rubber with a specific elastic modulus range to improve ground contact area and wear resistance
Implementation Method 2
by increasing the number of the sipes formed in the land portion block, an edge component that scratches the road surface can be increased, and therefore braking performance on the ice and snow road is improved
Data Source
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AI summary
In a pneumatic tire 10 according to the present invention, as an average sipe interval h is defined by an average interval of sipes adjacent to each other in a tire circumferential direction and an average pitch length L is defined by an average length of a repeating unit of blocks in the tire circumferential direction, a relation of 0.130 ≤ (h/L) ≤ 0.400 is fulfilled.