Tyre Crown Reinforcement Using Thin Metal Wires
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Solution Overview
Problem
Heavy-duty tires face challenges in maintaining endurance and wear performance under varying conditions, with increased rolling resistance and higher temperatures leading to tire wear issues, while existing solutions either compromise on mass or increase manufacturing costs.
Innovation Solution
A tire design with a radial carcass reinforcement featuring at least three working crown layers of unitary metal wires with specific dimensions and elastic properties, along with a rubber mixture formulation that enhances circumferential rigidity and reduces polymer mixture thickness, thereby minimizing mass and manufacturing costs while maintaining endurance and wear performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional crown reinforcement layers are used with thicker rubber mixtures and larger cables, then endurance and wear performance are maintained, but mass and manufacturing costs increase
Solution Approach 1:
The patent changes the physical parameters of the reinforcing elements by using unitary metal wires with diameters between 0.20-0.40mm instead of traditional larger cables, and reduces rubber mixture thickness to 2-4mm while maintaining structural integrity through optimized wire spacing of 0.5-1.5mm
Solution Approach 2:
The patent employs composite construction by combining multiple materials: unitary metal wires (steel or other metals), rubber mixtures with specific viscoelastic properties, and calendering layers, creating a multi-material crown reinforcement structure that optimizes both strength and weight
2Strength
If traditional crown reinforcement layers with larger cables and thicker rubber mixtures are used, then structural strength is maintained, but rolling resistance increases
Solution Approach 1:
The patent reduces energy losses by optimizing parameters including rubber mixture thickness (2-4mm), wire diameter (0.20-0.40mm), and wire spacing (0.5-1.5mm), creating a lighter crown reinforcement structure that reduces hysteresis and rolling resistance while maintaining strength
Solution Approach 2:
The patent applies local quality optimization by varying the properties of different components: using specific rubber compound formulations in calendering layers, optimizing wire distribution patterns, and adjusting layer thicknesses locally to achieve optimal balance between strength and energy efficiency
3Weight of moving object
If unitary metal wires with smaller diameters and closer spacing are used, then mass is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges to balance mass reduction with manufacturability: wire diameters of 0.20-0.40mm, spacing of 0.5-1.5mm, and rubber thickness of 2-4mm, providing clear manufacturing targets that achieve weight reduction without excessive precision demands
Solution Approach 2:
The patent segments the crown reinforcement into multiple thin layers (2-4 rubber layers per wire layer) with distributed unitary wires, which simplifies the manufacturing process by allowing incremental assembly and quality control at each stage rather than requiring high precision in a single thick layer
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 design achieves equivalent endurance and wear performance to traditional designs with reduced mass and manufacturing costs, improved rolling resistance, and enhanced circumferential rigidity, reducing the risk of crack initiation and promoting even tread wear.
Implementation Method 1
the modulus of elasticity under tension at 10% elongation of at least one calendering layer of at least one working crown layer being greater than 9 MPa and the maximum value of tan(δ), denoted tan(δ) max, of said at least one calendering layer of at least one working crown layer being less than 0.100
Data Source
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AI summary
The invention relates to a tyre comprising a crown ply formed by at least three working crown layers of reinforcing elements. According to the invention, in a meridian plane, the thickness of the layers, measured in the equatorial plane, is less than 5 mm; the reinforcing elements of the layers are individual metal wires having a diameter of less than 0.50 mm; the distance between the reinforcing elements, measured along the normal to the direction of the centre line of the wire, is strictly less than 1 mm; the axial width of each of the layers is greater than 60% of the axial width of the tread; the tensile modulus of elasticity at 10% elongation of at least one skim coat of at lest one working crown layer is greater than 9 MPa; and the maximum tan(δ) value of the skim coat is less than 0.100.