Abstract
High-speed permanent magnet (PM) machines are widely used because of their high-power density and high efficiency. The high rotation speed also inevitably subjects the PMs to high centrifugal load, which might damage them due to their inherent mechanical vulnerability, such as a much lower tensile strength than the compressive strength. To robustly transfer the torque from the magnet to the shaft, the outer diameter of the laminated rotor core is larger than the inner diameter of the rotor frame to ensure tight contact while working at 20,000 rpm. Motor manufacturing requires the shrink-fit method to assemble the rotor frame and rotor core. However, after the shrink-fit assembly, unexpected local delamination and buckling are observed on the rotor core part. Utilizing finite element simulation, we study the internal stress of assembling these two parts at the provided interference. Simulation results indicate the reasons for the delamination and buckling of the rotor core part and provide suggestions for improving the assembly.
