Tire Center Block Rigidity via Lateral Groove and Sipe Optimization
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Solution Overview
Problem
There is a trade-off between dry steering stability and on-ice performance in tires due to the increase in the number and length of sipes and lateral grooves, which compromises block rigidity, necessitating a solution that enhances both performance metrics simultaneously.
Innovation Solution
A tire design featuring a tread portion with five land regions, including a center land region divided by penetrating sipes, high rigidity regions, and strategically positioned lateral grooves and closed sipes, where the lengths and orientations of these features are optimized to maintain block rigidity while enhancing edge effect for both dry and icy surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number and length of sipes and lateral grooves are increased to improve on-ice performance, then edge effect is enhanced, but block rigidity decreases leading to deteriorated dry steering stability
Solution Approach 1:
The patent applies local quality by creating high rigidity regions with specific groove patterns in certain areas of the tread while allowing different patterns in other areas. The center land region has a specific configuration of lateral grooves and closed sipes that maintains block rigidity, while other regions may have different patterns optimized for their specific functions, thus achieving both rigidity and edge effect locally where needed
Solution Approach 2:
The patent segments the tread pattern into distinct functional regions including center land region, intermediate land region, and shoulder land region, each with optimized groove and sipe configurations. This segmentation allows different areas to serve different purposes - center regions maintain rigidity for steering stability while edge regions provide edge effect for ice performance
2Reliability
If the number and length of sipes and lateral grooves are increased to enhance edge effect, then on-ice performance is improved, but dry steering stability deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the lengths, widths, and spacing of lateral grooves and closed sipes. Specific parameters such as the length of lateral grooves (0.05-0.2 times tread width) and the spacing between closed sipes are optimized to maintain block rigidity while providing sufficient edge effect, thus improving ice performance without sacrificing steering stability
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 achieves high levels of both dry steering stability and on-ice performance by maintaining block rigidity through the formation of high rigidity regions and optimizing edge lengths, ensuring effective traction on various road conditions.
Implementation Method 1
the on-ice performance is secured by road surface digging frictional force (edge effect) caused by edges of the sipes and the lateral grooves
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A tire comprises center blocks (4) comprising a first center lateral groove (5A) and a second center closed sipe (6a) opposed to each other in a tire axial direction, and a second center lateral groove (5B) and a first center closed sipe (6b) axially opposed to each other. Lengths thereof satisfy the followings: LA/LA0 ≤ 1/2, LB/LB0 ≤ 1/2, Lb/Lb0 in a range of from 1/3 to 2/3, La/La0 in a range of from 1/3 to 2/3, LA <La, (LA + La) <LA0, LB <Lb, and (LB + Lb) <LB0. The center blocks (4) comprise a high rigidity region extending continuously between penetrating sipes (3) and between a first imaginary line passing through terminating ends of the first center lateral groove and the first center closed sipe and a second imaginary line passing through terminating ends of the second center lateral groove and the second center closed sipe.