Robotic disassembly of permanent magnet electric motors.

Abstract

This paper focuses on the disassembly of permanent magnet (PM) motors, which are the type of motor commonly used in electric vehicles (EVs). To handle the expected massive volume of PM motors available for remanufacturing as these EVs reach the end of their service life, efforts must be focussed on reducing manual labour during disassembly. In this study, the problem of removing a rotor from the stator in a PM motor using robots was explored. This is a challenging problem in PM motor disassembly because of the destabilising forces exerted by the magnets in the rotor. To prevent damage to the rotor and stator, an optimized disassembly path is generated using a model of the magnetic forces so that the rotor is centred relative to the stator while being pulled out. By following the optimized disassembly path and avoiding contact between the rotor and stator, the maximum disassembly force can be reduced by 49% and 38%, respectively, compared to when the rotor is off-centred or in contact with the stator.