Tire Bead Flanging Element for Crack Propagation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Radial tires for heavy civil engineering vehicles face degradation due to bending cycles, leading to rupture of metal reinforcement elements in high carcass reinforcement turn-up tires and cracking of polymeric materials in low turn-up tires, necessitating frequent replacements.
Innovation Solution
Incorporating a flanging element made of textile material with at least two edging layers, which are in continuous contact with the carcass reinforcement turn-up, to slow down crack propagation and reduce stress and deformation in the polymeric materials, thereby blocking cracks and enhancing the endurance of the tire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high carcass reinforcement turn-up is used, then the tire structure strength is improved, but the metal reinforcement elements rupture due to bending cycles
Solution Approach 1:
A flanging element made of flexible material (textile or polymer) is introduced as an intermediary between the metal carcass reinforcement and the polymeric materials. This flanging element absorbs bending stresses and prevents direct stress transfer that causes metal element rupture, thereby resolving the contradiction between structural strength and metal element durability
Solution Approach 2:
The tire bead incorporates a composite structure combining metal carcass reinforcement elements with a flexible flanging element made of textile or polymeric material. This composite construction allows the metal elements to provide structural strength while the flexible flanging material protects them from bending-induced rupture, simultaneously achieving both strength and reliability
2Reliability
If low carcass reinforcement turn-up is used, then the metal reinforcement element rupture is prevented, but the polymeric materials crack due to bending cycles
Solution Approach 1:
The flanging element serves as a protective intermediary layer between the metal carcass reinforcement and the polymeric materials. It absorbs bending stresses and prevents stress concentration at the turn-up end, thereby preventing crack initiation and propagation in the polymeric materials while maintaining metal element durability
Solution Approach 2:
The flexible flanging element is positioned in advance at the carcass reinforcement turn-up to cushion and absorb bending stresses before they can reach the polymeric materials. This pre-cushioning effect prevents stress concentration and crack formation in the polymeric materials during bending cycles
3Strength
If carcass reinforcement turn-up height is increased, then the anchoring of carcass reinforcement is improved, but the bending stress concentration increases
Solution Approach 1:
The flanging element acts as a stress-distributing intermediary between the carcass reinforcement and surrounding materials. It allows the turn-up height to be increased for better anchoring while the flexible flanging material distributes bending stresses, preventing stress concentration and potential failure points
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to improving the endurance of the beads of a radial tire for a heavy civil engineering vehicle, by blocking the cracks that are initiated in the end turn-up area of the carcass reinforcement and that propagate in the adjacent polymer materials, bringing about the deterioration of the bead in the long term. According to the invention, an edging element (23), consisting of at least two edging layers made of textile material reinforcing elements, is in continuous contact with the turn-up (211) of the carcass reinforcement between a first point of contact (A2) on the axially inner turn-up surface (211a) of the carcass reinforcement, corresponding to a first end (I2) of the edging element, and a last point of contact (B2) on the axially outer turn-up surface (211b) of the carcass reinforcement.