Mechanical Variable Magnetic Gear Transmission: Concept and Preliminary Research

This letter presents a novel concept of anon-contactvariable transmission mechanism using a coaxial magnetic gear. Conventional variable transmissions have provided a function of a robust transmission shifting; However, their inherentcontact-transmission manners such as traditional dog clutch, pulley, and load sensitive component-based mechanisms have increased their complexity, size, and weight, which restricts miniaturization and continuous operations of the system. The proposed coaxial magnetic gear-based variable transmission provides anon-contacttransmission ratio shifting mechanism by mechanically changing magnetic harmonics between coaxial components of the magnetic gear. Therefore, it may provide various features derived from thenon-contactpower transmission such as uninterrupted and seamless transmission ratio shifting, backdrivable and transparent dynamics, series elastic actuation-like properties, and inherent over-load protection with an expanded operable output range. A design, mathematical model, and simulation using a finite element method magnetics of the proposed mechanism are presented. Lastly, the transmission ratio shifting is demonstrated with a prototype to verify the feasibility of the proposed mechanism.