Tire Crown Reinforcement with Decoupling Layer
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Solution Overview
Problem
Current heavy-duty tires face challenges in maintaining endurance and wear resistance, especially under high-speed and long-distance conditions, due to shear stresses and increased operating temperatures, which lead to cracks and reduced performance.
Innovation Solution
A tire design featuring a radial carcass reinforcement with a crown reinforcement comprising two working crown layers decoupled by a first layer of rubber compound with a low elastic modulus and a second layer of polymer compound in contact with the carcass reinforcement, along with circumferential metal reinforcing elements, to distribute shear stresses and improve rolling resistance and cornering stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a layer of rubber compound is placed between the ends of working crown layers to decouple them, then shear stresses are reduced and endurance is improved, but rolling resistance increases due to higher energy loss in the rubber compound
Solution Approach 1:
The patent changes the physical parameters of the rubber compound layer by specifying precise ranges for elastic modulus (0.5-8 MPa) and loss factor (tan δ < 0.100). These parameter adjustments optimize the balance between decoupling effectiveness for endurance and energy loss for rolling resistance.
Solution Approach 2:
The patent uses a composite structure combining rubber compound layers with specific working crown layers. The rubber compound acts as an intermediary material with tailored properties (low elastic modulus and low loss factor) to achieve both stress distribution and energy efficiency.
2Reliability
If the elastic modulus of the rubber compound layer is reduced to improve decoupling and reduce shear stresses, then endurance improves, but the structural strength and stability of the crown reinforcement decrease
Solution Approach 1:
The patent carefully selects the elastic modulus parameter within a specific range (0.5-8 MPa) to achieve optimal decoupling effect while maintaining sufficient structural strength. This parameter optimization resolves the contradiction between softness for stress distribution and stiffness for structural integrity.
Solution Approach 2:
The rubber compound layer serves as an intermediary between working crown layers, with its mechanical properties tuned to provide both stress relief and structural support. The low elastic modulus allows it to act as a stress-absorbing mediator while still maintaining overall crown reinforcement stability.
3Force
If circumferential reinforcing elements are added to the crown reinforcement, then load bearing capacity and cornering stiffness are improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the crown reinforcement into distinct functional layers: working crown layers at specific angles, circumferential reinforcing elements at different positions, and rubber compound layers for decoupling. This segmentation allows each component to perform its specific function while maintaining overall system manageability.
Solution Approach 2:
The circumferential reinforcing elements serve multiple functions simultaneously: they provide load bearing capacity, enhance cornering stiffness, and work in conjunction with the rubber compound layers for stress distribution. This multi-functionality justifies the added structural complexity.
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, maintains wear resistance, and reduces rolling resistance, contributing to lower fuel consumption while maintaining dynamic properties and cornering stiffness, even as the tire wears.
Implementation Method 1
a first layer C of rubber compound being placed between at least the ends of the said at least two working crown layers, the elastic modulus under tension at 10% elongation of the first layer C being less than 8 MPa, the maximum tan(δ) value, denoted tan(δ)max, of the first layer C being less than 0.100
Implementation Method 2
the crown reinforcement comprising at least one layer of circumferential metal reinforcing elements
Data Source
AI summary
Tire comprising a crown reinforcement formed of at least two working crown layers of reinforcing elements, a first layer C of rubber compound being placed between at least the ends of the said at least two working crown layers, a second layer S of polymer compound being in contact with at least one working crown layer and in contact with the carcass reinforcement and the crown reinforcement comprising at least one layer of circumferential reinforcing elements. The elastic modulus under tension at 10% elongation of the first layer C is less than 8 MPa, the maximum tan(δ) value, denoted tan(δ)max, of the first layer C is less than 0.100, and the complex dynamic shear modulus G*, measured at 10% and 60° C. on the return cycle, of the said second layer S of polymer compound is greater than 1.35 MPa.