Structural Design Evaluation of Integrated Rotor Hub and Shaft for a High-Speed Surface Mounted Radial Flux Permanent Magnet Synchronous Motor

Abstract

Increasing the reliability and power density of a surface-mounted permanent magnet synchronous machine (SPMSM) is crucial due to the broader applications in the automotive and aerospace sectors. Concerns with such machines are that the overall rotating assembly experiences significant mechanical loads due to the rapid rotational speeds, making it exceptionally challenging to design the structural integrity of these components. This study's main objective is to offer a scientific justification for designing an integrated rotor hub and shaft through efficient Finite Element Modeling (FEM) and integration strategies to maximize the rotating assembly durability of a 150kW radial flux SPMSM spinning at 20,000 rpm. The optimization of integrated topology is evaluated based on a multiphysics platform, along with studies conducted on motor assembly eigen frequency. The integrated approach combining the shaft and rotor hub made of AISI 4340 solely saves 1.84kg, removing the necessity of standard components such as balancing end clamp plates, locknuts, and washers. Lower masses are proportional to lower centrifugal forces, reducing radial stress and promoting component/assembly stiffness.