Compressed Coil Manufacturing with Groove-Secured Wire Termination
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Solution Overview
Problem
Current compressed coil manufacturing techniques are inadequate for stranded or litz wires, as they often damage the coil terminations during the compression process, limiting the use of high fill factor coils in high-power density electrical machines.
Innovation Solution
A method and system involving a bobbin with a spindle and flange, along with a die, that accommodates the wire and minimizes damage to the lead sections by using grooves to secure the wire terminations, allowing for the use of twisted stranded wires and achieving high fill factors without damaging the coil terminations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current compressed coil manufacturing techniques are used, then coil compression is achieved, but the coil terminations are damaged
Solution Approach 1:
The invention divides the coil structure into two distinct zones: a compressed zone for the coil windings and an uncompressed zone for the lead sections. This segmentation is achieved through the compression tooling design that applies compression forces only to the winding area while leaving the lead sections untouched, thereby maintaining termination integrity while achieving coil compression.
Solution Approach 2:
The invention applies different mechanical properties to different parts of the coil assembly. The coil windings are compressed to achieve high fill factor and reduced thermal resistance, while the lead sections are kept uncompressed to maintain their mechanical integrity and electrical connectivity. This local differentiation of mechanical treatment resolves the contradiction between compression benefits and termination protection.
2Loss of energy
If stranded or litz wire is used, then AC losses are reduced, but current manufacturing techniques cannot process it without damage
Solution Approach 1:
The invention performs preliminary positioning of the lead sections in uncompressed regions before the compression process. This preliminary arrangement ensures that during subsequent compression, the lead sections are already protected from damaging forces, enabling the use of delicate stranded or litz wires that would otherwise be damaged by conventional compression techniques.
3Ease of manufacture
If single strand wire is used, then manufacturing is easier, but skin and proximity effects increase AC losses
Solution Approach 1:
The invention changes the conductor parameter from single solid strand to stranded or litz wire construction. This parameter change reduces the skin effect and proximity effects, thereby reducing AC losses. The accompanying process modification (protected compression) enables this parameter change to be implemented without manufacturing difficulties.
Data Source
Figure 1a~1d
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AI summary
A method of manufacturing a compressed coil and a system for holding a wire during the manufacture of a compressed coil are disclosed. The method includes providing a wire including a first lead section, a central section and a second lead section. The central section of the wire is wound around a bobbin to form a coil. A punch top is located over an end of the bobbin such that the end of the bobbin is located at least partially within a through-hole of the punch top. A second lead section of the wire is located within a groove in an outer surface of the punch top or bobbin and pressure is applied to the bobbin and/or punch top to compress the coil.