Tire Crown Reinforcement with Circumferential Elements
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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 with a radial carcass reinforcement featuring a crown reinforcement structure, including skim layers of polymer compound with specific elastic modulus and loss factor values, and a layer of circumferential reinforcing elements, optimized for improved rolling resistance and cornering stiffness, while maintaining endurance and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional crown reinforcement structure is used, then wear resistance is maintained, but rolling resistance increases and fuel consumption rises
Solution Approach 1:
The invention changes the elastic modulus parameter of the skim layer rubber compound to a specific range (4.0-8.0 MPa) to reduce rolling resistance while maintaining wear resistance through optimized material properties
Solution Approach 2:
The invention uses composite rubber compounds with specific tan(δ)max values (<0.100) and controlled macro dispersion coefficients (Z≥65) to achieve both low rolling resistance and high wear resistance through material composition optimization
2Productivity
If high speed and long distance running conditions are applied, then distance travelled increases and wear is reduced, but tire endurance deteriorates due to shear stresses and temperature rise
Solution Approach 1:
The invention optimizes the loss factor parameter tan(δ)max to be less than 0.100 and elastic modulus to 4.0-8.0 MPa, which reduces heat generation from shear stresses while maintaining structural integrity under high-speed and long-distance conditions
Solution Approach 2:
The invention applies specific material properties locally to the skim layers and crown reinforcement areas that are most susceptible to thermal and shear stress, using targeted elastic modulus and tan(δ) values in these critical zones
3Strength
If circumferential reinforcing elements are added, then cornering stiffness and rolling resistance improve, but device complexity increases
Solution Approach 1:
The invention segments the crown reinforcement into distinct functional layers: working crown layers for primary reinforcement, skim layers for stress distribution, and circumferential reinforcing elements for enhanced stiffness, with each layer having optimized material properties
Solution Approach 2:
The circumferential reinforcing elements serve multiple functions simultaneously: enhancing cornering stiffness, reducing rolling resistance, and providing structural support, thereby justifying the added complexity through multi-functional performance
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 enhances rolling resistance, cornering stiffness, and endurance, reducing fuel consumption and maintaining performance even as the tire wears, with lower elastic modulus values for the skim layers and the presence of circumferential reinforcing elements contributing to these improvements.
Implementation Method 1
the elastic modulus under tension at 10% elongation of at least one skim layer of at least one working crown layer being less than 8.5 MPa and the maximum value of tan(δ), denoted tan(δ)max, of the said skim being less than 0.100
Implementation Method 2
the complex dynamic shear modulus G*, measured at 10% and 60° C. on the return cycle, of the said first layer S of polymer compound being greater than 1.35 MPa
Data Source
AI summary
Tire comprising a crown reinforcement formed of at least two working crown layers each formed of reinforcing elements inserted between two skim layers of rubber compound. First layer S of polymer compound is in contact with a working crown layer and the carcass reinforcement. The crown reinforcement comprises a layer of circumferential reinforcing elements. The elastic modulus under tension at 10% elongation of a skim layer of a working crown layer is less than 8.5 MPa, the maximum value of tan(δ) of the skim layer of a working crown layer is <0.100. First layer S comprises a filled elastomer blend having a macro dispersion coefficient Z≥65 and a maximum tan(δ) value <0.100 and its complex dynamic shear modulus G*, measured at 10% and 60° C. on the return cycle is >1.35 MPa.