Tyre carcass reinforcement endurance via low modulus elastomer
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Solution Overview
Problem
Heavy-duty tires face endurance issues due to 'fatigue-fretting' and 'fatigue-corrosion' phenomena, leading to reduced lifespan and increased manufacturing costs, particularly under severe driving conditions.
Innovation Solution
A tire design with a radial carcass reinforcement featuring a calendering layer made of an elastomeric mixture with a low modulus of elasticity, based on natural rubber or synthetic polyisoprene, and a reinforcing filler like silica or alumina, which reduces corrosion and fatigue, while maintaining acceptable manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the rubber layer forming the inner wall of the tire cavity is increased to minimize permeability and improve durability, then the tire's airtightness and endurance are improved, but the manufacturing cost increases
Solution Approach 1:
The invention changes the chemical composition parameters of the rubber layer by incorporating specific anti-oxidizing agents (such as hindered phenols, aromatic amines, or their derivatives) and controlling the ratio of rubber compounds. This chemical parameter modification reduces permeability to oxygen and moisture without requiring increased layer thickness, thereby maintaining durability while controlling manufacturing costs
Solution Approach 2:
The invention creates a composite rubber layer by combining base rubber materials (such as natural rubber, synthetic rubber) with specific additives including anti-oxidizing agents, reinforcing fillers, and processing aids. This composite structure achieves superior barrier properties against permeation at optimized thickness levels, balancing performance and manufacturing cost
2Duration of action of moving object
If small diameter wires are used in carcass reinforcement cables to improve flexibility and bending endurance, then the cables exhibit better flexibility and high endurance in bending, but the cables become more susceptible to fatigue-corrosion due to increased surface area to volume ratio
Solution Approach 1:
The invention introduces an intermediary protective layer or coating on the wire surface that acts as a barrier between the metal and corrosive agents. This intermediary layer (such as zinc coating, epoxy coating, or polymer sheathing) prevents direct contact between corrosive substances and the wire, thereby reducing fatigue-corrosion while maintaining the flexibility benefits of small diameter wires
Solution Approach 2:
The invention creates an inert or protective environment around the wires by using corrosion-resistant materials as sheathing or coating. This protective environment isolates the wire from oxygen and moisture, significantly reducing the rate of oxidation and corrosion even when using small diameter wires with high surface area to volume ratio
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 endurance and reduced manufacturing costs, with enhanced resistance to corrosion and fatigue, maintaining performance under various driving conditions without increasing production costs.
Implementation Method 1
The modulus of elasticity under tension at 10% elongation of at least the calendered layer closest to the internal cavity of at least the carcass reinforcement layer closest to the internal cavity is less than 8,5 MPa
Data Source
Figure 1
AI summary
The invention relates to a tyre having a radial carcass reinforcement, consisting of at least one layer of metal reinforcing elements inserted between two calendering layers of an elastomeric compound. According to the invention, the tensile modulus of elasticity at 10% elongation of at least the calendering layer closest to the inner cavity of at least the carcass reinforcement layer closest to the inner cavity is less than 8.5 MPa, and at least said calendering layer closest to the inner cavity of at least the carcass reinforcement layer closest to the inner cavity is an elastomeric compound comprising a reinforcing filler consisting of a silica- and/or alumina-type white filler.