Mechanical Design of Magnetic Gearboxes Optimized for Assembly

Abstract

Magnetic gearing is a developing technology that utilizes magnetic forces to transmit torque through a system. Unlike traditional gears that rely on teeth engagement to transmit motion and torque, interacting magnetic fields in a magnetic gear transfer the torque with no contact area required. Early magnetic gearbox designs stemmed from an electromagnetic design, however, at larger scales the assembly process as well as electromagnetic design drives the overall mechanical design, due to high magnetic forces and stresses during the assembly. The development of magnetic gearboxes involves the optimization of the assembly process, the electromagnetic design and the mechanical performance to achieve a design that is robust, efficient, manufacturable, and economical. Each of these attributes is necessary to advance the technical readiness for applications as varied as wind turbines or robotics. These qualities were sought in the design of two new magnetic gearboxes which have been manufactured and tested. The mechanical design of the multistage gearbox established a repeatable assembly process that could be upscaled without compromising the structural integrity of the components. Design variants were simulated and tested to limit bending and shear stresses in the gearbox, whilst maintaining the electromagnetic performance of the system. The mechanical design of the modular magnetic gearbox established a new rotor design where manufacturability and configurability were improved to make the gearbox ideal for applications that require varying gear ratios.