Lightweight Tyre Crown Reinforcement with UHT Cables
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Solution Overview
Problem
Heavy-duty tires face challenges in maintaining endurance and road hazard resistance while reducing mass, as existing solutions either increase manufacturing costs or compromise on performance due to the addition of reinforcing elements, which are prone to oxidation and rupture under high deformation.
Innovation Solution
A tire design with a radial carcass reinforcement featuring a crown reinforcement of metal cables with a diameter less than 1.3 mm, UHT-grade wires, and elastomeric mixtures with a macro dispersion Z score greater than 85, and a circumferential reinforcing layer with specific elastic moduli and dispersion characteristics, reducing metal mass while maintaining endurance and resistance to road hazards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional layers of reinforcing elements are added to improve endurance, then tire endurance improves, but tire mass increases
Solution Approach 1:
The patent changes the material parameters by using cables with diameter less than 1.3 mm and UHT-grade wires with specific mechanical properties (breaking force ≥ 4180-2130xD MPa), replacing traditional heavier reinforcing elements while maintaining the required endurance performance through optimized cable specifications
Solution Approach 2:
The patent employs composite construction by combining multiple layers of cables with different orientations (working crown layers at 10°-45° angles, circumferential layer at 0°±2.5°, triangulation layer at 45°-90°) and integrating them with elastomeric mixtures having specific properties (macro dispersion Z score > 85, elastic modulus < 8.5 MPa at 10% elongation), creating a lightweight yet durable composite structure
2Strength
If metal cables are used for crown reinforcement, then structural strength improves, but oxidation resistance deteriorates
Solution Approach 1:
The patent uses circumferential reinforcing elements made of inextensible metallic elements with lower oxidation resistance but sufficient functional life, positioned to provide immediate structural support while the elastomeric mixture protects against oxidation during the tire's service life
Solution Approach 2:
The patent creates a protective composite system where elastomeric mixtures with high carbon black content (≥50 phr) and specific properties (macro dispersion Z score > 85, electric resistivity log(p) > 8) envelop the metal cables, providing oxidation barrier while maintaining structural strength through the combined cable-elastomer structure
3Strength
If circumferential reinforcing elements are added, then resistance to crown deformation improves, but manufacturing complexity increases
Solution Approach 1:
The circumferential layer of inextensible metallic elements serves multiple functions: it provides immediate resistance to crown deformation, acts as a stable foundation for the working crown layers, and contributes to overall tire structure rigidity, thereby achieving multiple structural benefits with a single layer that simplifies the overall design
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 achieves improved endurance and resistance to road hazards by reducing metal mass and limiting oxidation, while maintaining satisfactory cohesion and rolling resistance, as demonstrated by tests on stony ground and aggressive surfaces.
Implementation Method 1
at least said radially outermost calendering layer of at least the radially outermost working crown layer being characterised in that it has a macro dispersion Z score greater than 85
Implementation Method 2
the elastic modulus under tension at 10% elongation of at least said radially outermost calendering layer of at least the radially outermost working crown layer being less than 8.5 MPa
Implementation Method 3
the reinforcing elements of said at least two working crown layers being metal cables having a diameter less than 1.3 mm, at least a wire of each metal cable of at least one working top layer being of at least UHT grade
Implementation Method 4
with a breaking force ≥ 4180-2130xD MPa
Implementation Method 5
the top reinforcement comprising at least one layer of circumferential reinforcing elements... the elastic modulus under tension at 10% elongation of at least said radially outermost calendering layer being less than 8.5 MPa
Data Source
AI summary
The invention relates to a tyre (1) comprising a crown reinforcement made up of two working crown layers (41, 43), the liner layers of which contain carbon black, and a layer (42) of circumferential reinforcement elements . According to the invention, the reinforcement elements of the working crown layers (41, 43) are metal cables with a diameter of less than 1.3 mm, at least one wire of each metal cable of at least one working crown layer is at least UHT grade, the modulus of elasticity in tension at 10% elongation of at least the radially outermost liner layer of at least the radially outermost working crown layer (43) is less than 8.5 MPa, and at least said radially outermost liner layer of at least the radially outermost working crown layer (43) has a macrodispersion value Z of more than 85.