Tire Crown Reinforcement Polymer Compound
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Solution Overview
Problem
Current heavy-duty tires experience reduced endurance and cornering stiffness due to shear stresses and cleavage in the crown reinforcement, especially under high-speed and overload conditions on twisty roads, leading to premature wear and cracking.
Innovation Solution
A tire design featuring a crown reinforcement with a first layer of polymer compound made from a filled elastomeric compound with a macro dispersion coefficient greater than or equal to 65 and a complex dynamic shear modulus greater than 1.35 MPa, which enhances cornering stiffness and endurance by improving the cohesion and thermal properties of the tire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tire uses conventional crown reinforcement structure with multiple layers of threads or cords, then the tire can provide basic structural support and load bearing capacity, but the endurance and cornering stiffness are reduced due to shear stresses and cleavage under high-speed and overload conditions
Solution Approach 1:
The patent changes the physical and chemical parameters of the polymer compound layer by specifying a macro dispersion coefficient Z ≥ 65 and complex dynamic shear modulus G* > 1.35 MPa. These parameter changes optimize the layer's ability to resist shear stresses while maintaining flexibility, directly resolving the contradiction between endurance and cornering stiffness
Solution Approach 2:
The patent introduces a composite structure by adding a polymer compound layer with specific viscoelastic properties between the carcass reinforcement and crown reinforcement. This composite material approach allows the tire to simultaneously achieve high endurance through energy dissipation and high cornering stiffness through controlled rigidity
2Productivity
If the tire operates at high speed over long journeys, then the distance travelled increases and wear is reduced, but the endurance of the crown reinforcement is detrimentally affected due to combined shear stresses and temperature rise causing cracks
Solution Approach 1:
The patent optimizes the thermal and mechanical parameters of the polymer compound layer by controlling its loss factor tan(δ) and shear modulus. These parameter changes enable the material to dissipate heat effectively during high-speed operation while maintaining structural integrity, preventing crack formation despite prolonged use
Solution Approach 2:
The polymer compound layer acts as an intermediary between the carcass reinforcement and crown reinforcement, absorbing and distributing thermal and mechanical stresses. This intermediary function protects the crown reinforcement from direct exposure to harmful combined stresses and temperature rises during high-speed long-distance operation
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 exhibits improved cornering stiffness and maintained endurance properties across varying wear levels, even under severe cornering stresses, with the polymer compound's properties contributing to reduced crack propagation and enhanced dynamic performance.
Implementation Method 1
the said first layer S of polymer compound being made up of a filled elastomeric compound having a macro dispersion coefficient Z greater than or equal to 65 and a maximum tan(δ) value, denoted tan(δ)max, less than 0.100 and the complex dynamic shear modulus G*
Implementation Method 2
enhances cornering stiffness and endurance by improving the cohesion and thermal properties of the tire
Data Source
AI summary
Tire comprising a crown reinforcement formed of at least two working crown layers of reinforcing elements, crossed from one layer to the other making with the circumferential direction angles comprised between 10° and 45°. A first layer S of polymer compound is in contact with at least one working crown layer and in contact with the carcass reinforcement, the first layer S of polymer compound extending axially as far as at least the axial end of the tread, the first layer S of compound polymer compound is made up of a filled elastomer blend having a macro dispersion coefficient Z greater than or equal to 65 and a maximum tan(δ) value, denoted tan(δ)max, less than 0.100 and its complex dynamic shear modulus G*, measured at 10% and 60° C. on the return cycle is greater than 1.35 MPa.