Tyre Crown Reinforcement Decoupling Shear Stress
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Solution Overview
Problem
Heavy-duty tires face endurance and wear issues due to shear stresses and increased operating temperatures, leading to cracks and reduced performance, especially under high-speed and long-distance conditions.
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 rubber mixture layer between them, a layer of circumferential reinforcing elements, and a tread, where the rubber mixture layer has a modulus of elasticity greater than 9 MPa and a tan(δ) max value less than 0.100, decoupling the working layers to distribute shear stresses and reduce rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a layer of rubber mixture is introduced between the ends of the working crown layers to create decoupling, then shear stresses are limited and endurance is improved, but rolling resistance increases due to higher tan(δ) values
Solution Approach 1:
The patent applies parameter changes by precisely controlling the elastic modulus (greater than 9 MPa) and tan(δ) (less than 0.100) of the rubber mixture layer. This optimization allows the layer to provide sufficient decoupling for endurance while minimizing energy loss from hysteresis, thus resolving the contradiction between reliability and energy efficiency.
Solution Approach 2:
The patent uses composite materials by combining rubber mixtures with specific viscoelastic properties (controlled modulus and tan(δ)) between the working crown layers. This composite structure provides both the mechanical decoupling needed for endurance and the low hysteresis required for reduced rolling resistance.
2Strength
If circumferential reinforcing elements are added to increase load capacity, then tire strength is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies segmentation by dividing the crown reinforcement into distinct functional layers: working crown layers for strength, a rubber mixture layer for stress distribution, and circumferential reinforcing elements for additional load capacity. This segmentation allows each layer to perform its specific function efficiently while maintaining overall structural integrity.
Solution Approach 2:
The circumferential reinforcing elements serve multiple functions: they provide additional load capacity, maintain tire shape under heavy loads, and work in conjunction with the crossed plies to distribute stresses. This multi-functionality justifies the added structural complexity by delivering multiple performance benefits from a single structural feature.
3Stability of the object's composition
If the rubber mixture layer has high cohesion to maintain layer integrity, then layer stability is improved, but rolling resistance increases due to higher hysteresis
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the viscoelastic parameters of the rubber mixture layer. By setting the elastic modulus greater than 9 MPa and tan(δ) less than 0.100, the layer achieves sufficient cohesion for structural stability while maintaining low hysteresis for reduced energy loss during cyclic 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 design enhances endurance and wear resistance while improving rolling resistance, contributing to lower fuel consumption by maintaining satisfactory cohesion and reducing shear stresses between the tire's layers.
Implementation Method 1
the modulus of elasticity under tension at 10% elongation of the layer C being greater than 9 MPa
Implementation Method 2
the maximum value of tan(δ), denoted tan(δ) max, of layer C being less than 0.100
Data Source
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AI summary
The invention relates to a tyre (1) comprising a crown reinforcement (4) formed by at least two working crown layers (41, 43) of reinforcing elements, a layer C of rubber mix being disposed between at least the ends of the at least two working crown layers (41, 43) and the crown reinforcement (4) comprising at least one layer (42) of circumferential reinforcing elements. According to the invention, the tensile modulus at 10% elongation of layer C is greater than 9 MPa and the maximum value of tan(δ), denoted tan(δ)max, of layer C is less than 0.100.