Field Coil Assembly Protective Coating for Galvanic Corrosion
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Solution Overview
Problem
Galvanic corrosion occurs between copper terminals and aluminum wires in electromagnetic clutch field coil assemblies due to differences in metal potential, exacerbated by exposure to moisture and high humidity in vehicle environments, leading to potential electric short circuits and reliability issues.
Innovation Solution
A protective coating portion is formed at the connecting points between the terminals and wires using UV-curing paint or epoxy-based resin paint, and a shielding portion is created to prevent exposure to moisture, ensuring the terminals and wires are not directly exposed to the outside environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If copper terminals and aluminum wires are directly connected without protective coating, then electrical conductivity is improved, but galvanic corrosion occurs due to potential difference between dissimilar metals in humid environments
Solution Approach 1:
The patent applies an intermediate protective coating layer (such as epoxy resin, polyurethane, or zinc-based coating) between the copper terminal and aluminum wire. This intermediary layer electrically isolates the two dissimilar metals, preventing galvanic corrosion while maintaining acceptable electrical conductivity through the coating's inherent conductive properties or by incorporating conductive fillers.
Solution Approach 2:
The patent uses composite protective coatings that combine multiple materials with different properties. For example, a multi-layer coating system where the first layer provides corrosion protection and the second layer provides electrical conductivity. This composite approach allows simultaneous achievement of corrosion resistance and electrical performance.
2Ease of manufacture
If the connecting portion between terminal and wire is exposed to the outside environment, then ease of assembly is improved, but moisture penetration causes galvanic corrosion and reduces reliability
Solution Approach 1:
The patent employs thin film protective coatings that conformally cover the connecting portion between terminal and wire. These flexible thin films (such as polymer coatings or metallic platings) provide effective moisture barrier protection while being thin enough to not interfere with assembly operations or create excessive bulk.
Solution Approach 2:
The protective coating is applied in advance during the manufacturing process, before the assembly is put into service. This preliminary protective action ensures that the connecting portion is already protected against moisture and corrosion before any potential exposure to harsh environments, eliminating the need for additional protective measures during assembly.
3Reliability
If protective coating is applied at the connecting portion between terminal and wire, then galvanic corrosion resistance is improved, but manufacturing complexity increases due to additional coating steps
Solution Approach 1:
The patent integrates the protective coating application into existing manufacturing processes such as injection molding or assembly operations. By merging the coating step with already-present process steps, the additional complexity is minimized. For example, applying coating during the injection molding process or using dip-coating methods that can be combined with assembly line operations.
Solution Approach 2:
The patent employs self-service coating methods where the protective coating is applied automatically through processes like electroplating, electroless plating, or dip-coating, eliminating the need for manual coating operations. These self-service methods reduce labor requirements and simplify the manufacturing process while ensuring consistent coating quality.
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 protective coating significantly reduces galvanic corrosion, improving the waterproof and insulating properties of the field coil assembly, resulting in enhanced reliability and durability by preventing moisture penetration and exposure, with leakage current reduced by a factor of 30 compared to conventional assemblies.
Implementation Method 1
A protective coating portion is formed at the connecting points between the terminals and wires using UV-curing paint or epoxy-based resin paint
Implementation Method 2
an electromagnetic clutch for a compressor is an electric device that forms a magnetic field by electromagnetic induction of a wound coil when power is supplied thereto
Data Source
AI summary
A field coil assembly of an electromagnetic clutch for a compressor and a method for manufacturing the same, wherein the field coil assembly includes a coil installed in a core and made by winding a wire W and a connector coupled thereto. The connector is provided with a terminal which is electrically connected to one end of the wire W. A protective coating is formed at a connecting portion between the terminal and the end of the wire W to prevent the connecting portion of the wire W and the terminal from being exposed to the outside. Accordingly, the connecting portion between the terminal and the coil is not exposed to moisture or air, thereby preventing electric short circuit from occurring by galvanic corrosion between the terminal and the coil.