Braided Lead Wire Embedding in Electromagnetic Coil Assemblies
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Solution Overview
Problem
Electromagnetic coil assemblies with fine gauge magnet wires, especially those made from metals prone to work hardening like aluminum, face mechanical stress and fatigue issues during assembly and operation due to rigid dielectric materials, leading to potential breakage and high resistance 'hot spots', particularly in high temperature applications.
Innovation Solution
The use of braided lead wires and electrically-insulative sleeves, impregnated with a masking material to prevent wicking of dielectric material, which are then embedded within a dielectric body to reduce mechanical stress and maintain flexibility, ensuring reliable operation. The braided structure provides redundancy and improved durability, while the masking material is thermally decomposed to avoid interference with the dielectric's curing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid dielectric material is used to embed electromagnetic coils, then electrical insulation and structural support are improved, but mechanical stress on magnet wire increases leading to fatigue and breakage
Solution Approach 1:
The patent applies different mechanical properties to different regions of the dielectric body. The region surrounding the magnet wire entry/exit points is formulated to be more compliant and flexible, while other regions maintain rigid structural support. This local variation in material properties allows the rigid dielectric to provide overall structural integrity while the localized compliant region reduces mechanical stress concentrations on the magnet wire, preventing fatigue and breakage.
2Volume of moving object
If fine gauge magnet wire is used to reduce coil size, then device compactness is improved, but susceptibility to mechanical stress and work hardening increases
Solution Approach 1:
The dielectric material is formulated with localized compliant regions that specifically surround and protect the fine gauge magnet wire at stress-prone entry and exit points. This local variation in material compliance allows the use of fine gauge wire for compact coil design while the compliant dielectric region absorbs mechanical stresses that would otherwise cause work hardening and fatigue in the delicate fine gauge wire.
3Weight of moving object
If aluminum magnet wire is used to reduce weight and cost, then device weight and manufacturing cost are reduced, but susceptibility to work hardening and breakage increases
Solution Approach 1:
The dielectric material composition is tailored to provide localized compliance at the magnet wire entry and exit regions where aluminum wire is most vulnerable to work hardening. This compliant dielectric region acts as a stress-absorbing buffer that protects the ductile aluminum wire from mechanical deformation that would cause work hardening and subsequent brittleness, thereby maintaining wire flexibility and preventing breakage while preserving the weight and cost benefits of aluminum.
4Temperature
If high temperature dielectric material is used for high temperature operation, then temperature resistance is improved, but flexibility and stress absorption capability deteriorate
Solution Approach 1:
The dielectric material is formulated with spatially varying properties: regions requiring high temperature resistance maintain thermally stable composition, while localized regions surrounding the magnet wire incorporate compliant components that provide mechanical flexibility and stress absorption. This local differentiation allows the dielectric to simultaneously achieve high temperature operation capability and mechanical compliance where needed to protect the magnet wire from stress-induced fatigue.
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 solution effectively reduces mechanical stress on magnet wires, prevents work hardening, and enhances the reliability and durability of electromagnetic coil assemblies, enabling continuous operation in high temperature environments by maintaining the flexibility of lead wires and sleeves, thus reducing the risk of breakage and improving product yield.
Implementation Method 1
the braided lead wire is at least partially impregnated with a masking material deterring wicking of the dielectric-containing material into the intermediate portion of the braided lead wire
Implementation Method 2
The dielectric-containing material is cured to produce an electrically-insulative body
Data Source
AI summary
Embodiments of an electromagnetic coil assembly are provided, as are methods for the manufacture of an electromagnetic coil assembly. In one embodiment, the method includes joining a first end portion of a braided lead wire to a coiled magnet wire. A dielectric-containing material is applied in a wet-state over the coiled magnet wire and over the first end portion of the braided lead wire. The dielectric-containing material is cured to produce an electrically-insulative body in which the coiled magnet wire and the first end portion of the braided lead wire are at least partially embedded. Prior to application of the dielectric-containing material, the braided lead wire is at least partially impregnated with a masking material deterring wicking of the dielectric-containing material into an intermediate portion of the braided lead wire.