Tyre Block Incision Depth Variation for Crack Resistance
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Solution Overview
Problem
Tires with incised rubber blocks experience premature degradation and cracking due to strong stresses on the residual rubber zone between incisions and groove bottoms, leading to reduced mechanical strength and rigidity.
Innovation Solution
The design of incisions with varying depths, featuring a first end part with maximum depth, a main part with lesser depth, and a connecting part with progressive depth variation, distributes stress concentrations within the block, reducing the risk of cracking on side faces and improving overall stiffness and grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If incisions extend deeply into the rubber block to improve water evacuation and grip, then grip performance is improved, but mechanical strength and resistance to cracking deteriorate
Solution Approach 1:
The incision depth is varied locally along its length, with the first end part extending deeper than the main part. This creates zones of different rubber thickness: a thinner zone at the end part for better water evacuation and grip, and a thicker residual rubber zone in the main part for maintaining mechanical strength and resisting cracking.
2Object-generated harmful factors
If incisions are made to improve grip on wet surfaces, then grip is improved, but the residual rubber zone experiences strong stresses leading to cracking
Solution Approach 1:
The depth parameter of the incision is changed along its length, creating a gradient from deeper at the end part to shallower in the main part. This parameter variation allows the incision to perform its water-cutting function while preserving sufficient residual rubber thickness in critical areas to withstand rolling stresses without cracking.
3Ease of manufacture
If uniform depth incisions are used to simplify manufacturing, then manufacturing is easier, but stress concentration occurs at the bottom of grooves leading to degradation
Solution Approach 1:
Rather than using uniform depth throughout, the incision is designed with local quality variations: a first end part with maximum depth for effective water cutting, and a main part with lesser depth to maintain adequate residual rubber thickness and distribute stress concentrations away from the groove bottoms.
Data Source
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AI summary
The invention relates to a tyre made from rubber-like material, comprising a tread including a plurality of blocks (22) delimited by grooves (12, 14) formed in the tread, at least one of said blocks comprising at least one incision (24) of length L that opens at least onto a first side face (22c) of the block. The depth of the aforementioned incision (24) varies along the length L, said depth being at its maximum at least in a first end portion (26) of the incision that opens onto the first side face (22c) of the block.