Design and fabrication of magnetic couplings in vacuum robots

Purpose - The purpose of this paper is to discuss the design and fabrication of magnetic couplings to use for vacuum robots. The permanent magnetic coupling (PMC) is appropriate for torque transmission in ultrahigh vacuum and highly clean environments. However, conventional structures of PMC are always unsuitable to use for vacuum robots. Design/methodology/approach - Two types of design scheme for radial magnetic couplings are introduced and compared. The major characteristic of the novel design scheme is that the inner part uses a nonmagnetic mantle to enclose the magnets and yoke, and the outer part uses two end closures to position magnets. The locating groove on the end closure may be manufactured as T-shape or dovetail shape. Findings - The 3D finite element analysis simulation results and experimental studies have demonstrated that the proposed Design B had a lower contamination rate and a higher transmission efficiency than the Design A. Research limitations/implications - The limitation of the research to date is that issues of control, path-planning, and communication have not yet been addressed. Practical implications - The proposed PMC is successfully applied in vacuum robots which uses combined direct drive techniques and magnetic transmit techniques. Originality/value - These results suggest that the proposed PMC is suitable for using in vacuum robots.