New Production Techniques for Electric Motors in High Performance Lightweight Applications

Lightweight high-efficiency electric motors are beneficial for mobility systems providing higher range for automotive applications or longer flight time for aerial applications. The emerging ironless motors already outperform iron-cored motors on efficiency and peak torque capability but still have lower rated specific power and torque. To close this gap and develop the all-around best motor technology for the automotive and aerial applications new production methods for both the stator and the rotor have been developed. For the stator the patented FiberPrinting technology is presented, which is based on a weaving process with the help of a tailor-made machinery, followed by molding process. In the rotor the rotating back iron of the double airgap motor design is made from a soft magnetic compound, produced with an injection molding process. To enable highest lightweight potential, the back iron is designed as a 2-component-part with soft magnetic material in the magnetic active areas and PA6-GF30 for the structural integrity. The combination of both technologies shows extreme potential in terms of lightweight design and electrical and magnetic losses, which is validated by simulations and first experiments of the manufactured components.