Lightweight Design and Manufacturing of Composites for High-performance Electric Motors

The global demand for carbon saving and green mobility is changing propulsion systems from combustion engines to electric motors. Today, battery capacities are still low and the range of automotive vehicles needs to be improved. In this context, high-performance electric motors of high energy efficiency as well as low weight are gaining in importance.In the present paper, two approaches for reducing weight of electric motor rotors are presented. First, a lightweight approach comprising a hybrid shaft made of carbon reinforced plastic and stainless steel are outlined. It is manufactured by a novel process chain, where dry filament winding is combined with centrifugal casting. The steel inlays are joined in-mold during centrifugal casting. The second approach demonstrates the replacement of electric sheets by soft magnetic compounds (SMC, iron filled polyamide compound). These SMC parts are produced in an innovative two-component injection molding process. The paper concludes with a concept for the assembly of the hybrid shaft with the SMC parts and the mechanical testing of the assembled lightweight rotor.