Magnetic-Superconductor Cryogenic Non-contact Harmonic Drive: Performance and Dynamical Behavior

Abstract

The objective of this development is to design, build and test a magnetic-superconductor cryogenic non-contact harmonic drive (MAGDRIVE). This harmonic drive is a mechanism provided with an input axle and an output hub with a great reduction ratio and it will be able to function at cryogenic temperatures. It is based on “non-contact magnetic teeth” instead of fitting teeth on a flexural wave as conventional harmonic drives are based on. Non-contact magnetic teeth are activated by a magnetic wave (similar to an electrical engine) and stabilized by the use of superconductor materials. This can solve the problems of contact wearing and mechanical fatigue. Superconductors are also used for non-contact bearings and for shielding the magnetic fields to avoid electromagnetic interferences or emission. The first preliminary analyses show very promising mechanical performances of the reduction gear. They have demonstrated that the transmitted torque density capability is independent of the size of the gear. Also, the choice of the material for the soft-magnetic teeth is not a critical decision provided that they have a minimum required magnetic permeability. Moreover, some dynamical simulations have shown that the reduction ratio is achieved.