Efficient Processes and Tools for Twisting of Flat Wires in Hairpin Motors

FAU has been working on the development of hairpin technology for several years. Special attention is paid to the handling and automation of the individual process steps along the stator manufacturing process with hairpin windings. One of these steps, the twisting of the hairpin ends, is the subject of this paper. First, a brief overview of the hairpin stator manufacturing process is given before different twisting processes are examined. Then, an analysis of an existing twisting machine is detailed and efforts are described to redesign it to combine individual repetitive twisting processes into fewer handling steps. A major goal of the work was to create a new device with maximum flexibility in the number of slots, stator geometry, and wire geometry. The paper outlines the general conditions and requirements defined for the device, describes the experiments conducted to test its applicability, and presents an evaluation of the results. This research is intended to contribute to the ongoing advancement of hairpin technology and to improve the flexibility and efficiency of stator manufacturing processes.