Tire Tread Stiffness and Edge Effect Trade-off
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Solution Overview
Problem
Existing tires face a trade-off between enhancing braking performance through increased tread stiffness and maintaining edge effect, as higher numbers of lateral grooves and sipes improve friction but decrease tread stiffness, leading to reduced front-rear force during braking.
Innovation Solution
A tire design featuring a tread portion divided by circumferential main grooves with shoulder land portions having two-stage lateral grooves and sipes, where the shallow groove depth increases and deep groove depth decreases in a specific ratio, maintaining edge effect while improving land portion stiffness for enhanced front-rear force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the number of lateral grooves and sipes is increased to enhance edge effect and braking performance, then frictional force with road surface increases, but tread stiffness decreases
Solution Approach 1:
The patent applies local quality by creating lateral grooves with varying depths across different regions. The groove depth increases from the inner side toward the outer side of the tread, allowing the outer region to provide enhanced edge effect while the inner region maintains tread stiffness. This gradient structure enables different parts of the same component to serve different functional purposes.
Solution Approach 2:
The patent introduces a depth dimension to the lateral grooves, transforming them from uniform shallow grooves to three-dimensional structures with varying depths. This dimensional change allows the grooves to provide both edge effect (through deeper outer portions) and maintain stiffness (through shallower inner portions), resolving the contradiction between friction enhancement and structural integrity.
Data Source
Figure 1
Figure 2(A)~2(B)
Figure 3(A)~3(B)
AI summary
While an edge effect is maintained, tread stiffness is improved to enhance braking performance. A first shoulder land portion 6A that is one of a pair of shoulder land portions has a plurality of first shoulder lateral grooves 10 each extending inward in a tire axial direction from an outer side in the tire axial direction with respect to a ground-contact edge T and having an inner end portion 10e that terminates within the first shoulder land portion 6A without being connected to a shoulder main groove 4A via a sipe, and first shoulder sipes 11 each provided between the first shoulder lateral grooves 10, 10.