Forming-Based Process Modeling of the Linear Winding Method

Funding: German Research Foundation (DFG)
Project: TE 508/56-1
Contact: Anna Komodromos M. Sc.
Status: Completed

Due to the increasing importance of electromobility the linear winding of noncircular coil bobbins (see figure a) has been analyzed in cooperation with the Institute of Production Science (KIT).

 

This was done considering the forming behavior of the copper wire: On the one hand, by the characterization of the plastic properties of the copper like the kinematic hardening (see figure b). On the other hand, by the examination of the bending process at the edge of the coil bobbin on the basis of essential influencing parameters. The tension superposed bending of the round wire results in a reduction of the cross section (flattening) in comparison to the area of the edges. Consequently, the ohmic resistance is increased and the efficiency of the electric motor is reduced (see figure c). The change in cross section contradicts the development of the clearance between wire and bobbin (see figure d). By means of the conducted examinations it was shown within which limits the process can be performed – under consideration of the influencing parameters in relation to the filling factor (see figure d).
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a) Process principle, b) Material characterization, c) Resistance of a coil winding, d) Clearance development