Commercial Vehicle Tire Belt Plies Brass Coating Copper Content
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Solution Overview
Problem
Commercial vehicle tires with multi-ply belts face challenges in achieving optimal corrosion resistance and adhesion for their steel cord plies, with existing brass coatings either compromising on adhesion or corrosion resistance based on copper content.
Innovation Solution
The tire features a brass coating with a copper content of 60-65% by weight for the working plies and 66-70% by weight for the cover ply, optimized to balance adhesion and corrosion resistance, with the cover ply having a thinner coating for enhanced protection and the working plies having improved adhesion with slightly reduced corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a brass coating with high copper content (66-70%) is applied to the cover ply, then corrosion resistance is improved, but adhesion is reduced
Solution Approach 1:
The patent applies different brass coating compositions to different belt plies based on their specific functional requirements. The cover ply receives a brass coating with 66-70% copper content optimized for corrosion resistance, while the working plies receive a brass coating with 60-65% copper content optimized for adhesion. This local differentiation resolves the contradiction by allowing each ply to have the coating properties most suitable for its specific role in the tire structure.
2Strength
If a brass coating with low copper content (60-65%) is applied to the working plies, then adhesion is improved, but corrosion resistance is reduced
Solution Approach 1:
The working plies are subjected to high shear forces and tensile forces, requiring optimal adhesion between the steel cords and rubber compound. The patent addresses this by applying a brass coating with 60-65% copper content to the working plies, which provides superior adhesion properties. The slightly reduced corrosion resistance is acceptable for these plies since the cover ply provides protective coverage.
3Ease of manufacture
If a uniform brass coating composition is applied to all belt plies, then manufacturing complexity is reduced, but overall durability is compromised
Solution Approach 1:
The patent implements a differentiated brass coating strategy where each belt ply receives a coating composition tailored to its specific functional requirements. The cover ply receives higher copper content (66-70%) for corrosion protection, while working plies receive lower copper content (60-65%) for optimal adhesion. This approach prioritizes overall tire durability over manufacturing simplicity, as the enhanced performance benefits outweigh the additional coating process 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
This configuration enhances the durability of the tire by improving corrosion resistance and adhesion of the belt plies, with the cover ply providing better protection against stones and the working plies maintaining load-carrying capacity and durability.
Implementation Method 1
the steel cords of each of the three belt plies are coated with brass for good elastomer adhesion
Implementation Method 2
a high copper content of the brass coating, while having a reduced adhesion, leads to improved corrosion resistance
Data Source
AI summary
A pneumatic commercial vehicle tire of radial design includes at least a three-ply belt, of which two belt plies are working plies and one radially outermost belt ply is a cover ply. Each of these belt plies includes reinforcements which are made of steel cord and which are embedded in elastomer. The steel cords of each of the three belt plies are coated with brass so as to provide for good elastomer adhesion. The brass coating of the reinforcement supports of the two working plies has a copper proportion of 60 wt. % to 65 wt. % and the brass coating of the reinforcement supports of the cover ply has a copper proportion of 66 wt. % to 70 wt. %.