Extensible Crown Reinforcement for Puncture-Resistant Civil Engineering Tires
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Solution Overview
Problem
Radial tires for heavy-duty civil engineering vehicles face challenges in puncture resistance, especially when encountering larger obstacles, as the forces exerted on the cords can exceed the hardness of the steel, leading to cuts in the reinforcing elements of the working layers, and existing crown architectures are less effective against such larger obstacles.
Innovation Solution
The tire features a crown reinforcement with all metal reinforcers being extensible, comprising two transverse reinforcer layers with different axial widths and at least one hooping layer with extensible metal elements, allowing for improved puncture and crack resistance while reducing the mass of the crown reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If inextensible metal reinforcers are used in working layers to provide stiffness and strength, then the tire structure gains rigidity and load-bearing capacity, but the tire becomes vulnerable to cuts and punctures when encountering larger obstacles
Solution Approach 1:
The patent changes the key parameter of metal reinforcer extensibility from inextensible to extensible. This allows the reinforcers to deform and absorb impact forces when encountering obstacles, preventing cuts and punctures while maintaining structural integrity through the elastomeric coating that enables reversible deformation
Solution Approach 2:
The patent creates a composite structure by coating metal reinforcers with elastomeric material. This composite enables the reinforcers to combine the strength of metal with the flexibility and energy-absorbing properties of elastomers, allowing them to resist both static loads and dynamic impacts from obstacles
2Reliability
If extensible metal reinforcers are used to improve puncture resistance, then the tire can better absorb impact forces, but the structural stiffness and load-bearing capacity may be compromised
Solution Approach 1:
The patent modifies the extensibility parameter of metal reinforcers to an optimal range that allows sufficient deformation for impact absorption while maintaining enough stiffness for structural support. The elastomeric coating enables controlled reversible deformation that preserves load-bearing capacity
Solution Approach 2:
The metal-elastomer composite structure combines the high strength of metal reinforcers with the energy-absorbing capabilities of elastomers. The composite maintains structural integrity under static loads while providing flexibility to withstand dynamic impacts without permanent deformation
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 significantly enhances puncture resistance and crack resistance, with a possible 20% improvement in travel distance before failure and a 22% reduction in tire mass, demonstrating effective absorption of forces and deformation without compromising the tire's behavior under various stresses.
Implementation Method 1
each extensible metal reinforcing element of each hooping layer having, in its rubberized state extracted from a polymer matrix, a structural elongation Asf at least equal to 0.5%, a total elongation at break Atf at least equal to 3%
Data Source
AI summary
A radial tire (1) for a heavy-duty vehicle, in which the reinforcing elements of each hooping layer (331, 332, 333), forming an angle at most equal to 5° with the circumferential direction, and the reinforcing elements of the transverse reinforcer layers (321, 322, 323), forming an angle of between 10° and 45° with the circumferential direction, are extensible and therefore such that, in their rubberized state extracted from a polymer matrix, their structural elongation As is at least equal to 0.5%, their total elongation at break At is at least equal to 3% and their tensile Young's modulus E is at most equal to 150 GPa.