Tyre Crown Reinforcement with Low Hysteresis Rubber Layer
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Solution Overview
Problem
Current heavy-duty tires face challenges in maintaining endurance and wear resistance while reducing rolling resistance, particularly under high-speed and long-distance conditions, due to shear stresses and temperature increases at the ends of the crown reinforcement layers.
Innovation Solution
A tire design with a radial carcass reinforcement featuring a crown reinforcement structure that includes at least two working crown layers with a first layer of rubber mixture between their ends, a layer of circumferential metallic reinforcing elements, and specific rubber mixture properties to reduce shear stresses and improve rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a layer of rubber mixture is placed between the ends of the working crown layers to create decoupling, then shear stresses are limited, but rolling resistance increases due to high hysteresis losses
Solution Approach 1:
The patent applies parameter changes by modifying the rubber mixture composition to achieve specific mechanical properties: elastic modulus between 8-15 MPa and tan(δ) between 0.08-0.12. This resolves the contradiction by finding optimal parameter values that provide sufficient decoupling for endurance while minimizing hysteresis losses that increase rolling resistance.
Solution Approach 2:
The patent uses composite materials by combining rubber mixture with specific fillers (carbon black, silica) and plasticizers in precise proportions. This composite approach creates a material that simultaneously provides the needed structural decoupling function and optimized energy dissipation characteristics to balance endurance and rolling resistance.
2Stability of the object's composition
If the elastic modulus of the rubber mixture layer is increased to improve cohesion, then layer stability improves, but rolling resistance increases due to higher energy losses
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the elastic modulus parameter within 8-15 MPa and tan(δ) within 0.08-0.12. This parameter optimization ensures the rubber layer maintains adequate cohesion for structural stability while minimizing hysteresis energy losses that would increase rolling resistance.
3Loss of energy
If circumferential reinforcing elements are added to reduce rolling resistance, then fuel consumption decreases, but the complexity of the tire structure increases
Solution Approach 1:
The patent applies multi-functionality by designing the rubber mixture layer to simultaneously perform multiple functions: decoupling the working crown layers to reduce shear stresses, providing structural cohesion, and minimizing hysteresis losses. This integrated approach reduces rolling resistance without proportionally increasing structural complexity.
Solution Approach 2:
The patent uses composite materials with circumferential reinforcing elements combined with specifically formulated rubber mixtures. This composite structure achieves reduced rolling resistance through the reinforcing elements while the optimized rubber composition maintains structural integrity without requiring excessive additional components.
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 design enhances endurance and wear resistance while lowering rolling resistance, contributing to reduced fuel consumption by distributing shear stresses and maintaining satisfactory cohesion and performance.
Implementation Method 1
a first layer C of rubber mixture being placed between at least the ends of said at least two working crown layers... to distribute the shear stresses over a greater thickness
Implementation Method 2
The loss factor tan(δ), denoted tan(δ) max, of the first layer C being less than 0.100... to improve the properties of the tire in terms of rolling resistance
Implementation Method 3
the modulus of elasticity under tension at 10% elongation of the first layer C being less than 8 MPa... maintaining satisfactory cohesion and performance
Data Source
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AI summary
The invention relates to a tyre comprising a crown reinforcement formed of at least two working crown layers of reinforcing elements, a first layer C of rubber compound being positioned between at least the ends of said at least two working crown layers, and the crown reinforcement comprising at least one layer of metal circumferential reinforcing elements. According to the invention, the elastic modulus at 10% tensile strain of the first layer C is less than 8 MPa and the maximum value of tan(delta), denoted tan(delta) max, of the first layer C is less than 0.100.