Calculation and Experimental Characterization of the Stiffness of Laminated Back Iron for Rotors of Axial Flux Machines

The update of the Mercedes-Benz strategy from “Electric first” to “Electric only” is accelerating the transformation towards an emission-free future, placing the focus on fully electric drives [1]. In addition to radial flux motors, which have been very common to date, axial flux motors offer new possibilities for drive topologies due to their comparatively small axial installation space, serve as enabler for compact dual drive units, for example.The special potential of axial flux motors lies in their combination of an extraordinary power-to-size, power-to-weight ratio with the highest level of efficiency [2, 3].

Taking the general requirements for the electric motor as a basis, the aim is to derive the mechanical requirements and determine the properties of the component parts. The standards for laminated sheet packages of radial flux motors that specify the electromagnetic and mechanical properties have been defined. So far, laminated sheet packages in the form of laminated back iron for rotors of axial flux motors have been specified in terms of their electromagnetic properties exclusively. The relevant standards therefore do not take into account any requirements relating to the axial strength and stiffness of laminated back iron. In this paper the author focuses on simulation and experimental validation of these mechanical properties of axial flux rotor back iron.