Advanced magnetically-stabilized couplings and bearings, for use in

Abstract

A rotary-arm drive includes a wobble-absorbing magnetic bearing (WAMB). One end of the arm engages a load-carrying surface. The other end rotates with a power-carrying rotary shaft. The arm transmits power at least one way between surface and shaft. The WAMB is between the first end of the arm and the surface. As to one aspect of the invention, the WAMB directly transmits force mechanically, but absorbs mismatched motion, between end and surface. Preferably the bearing has at least two elements (more preferably rolling elements, ideally balls) fastened to neither the end nor the surface. As to a second aspect, the drive is a traveling antirotation module. The first end rides on a fixed guideway that defines the surface; the other is fixed to a mechanical element forming the shaft and travels, carrying the arm, along a drive direction and is subject to undesired rotation about the axis. Thus the arm and its engagement with the guideway help restrain the element against rotation. The WAMB, at the first end of the arm, includes (1) the surface defined by the guideway, and (2) at least one other bearing surface traveling with the element and arm, and is magnetically secured against the guideway via rolling elements to absorb arm-guideway wobble. Also preferably the arm separates from the guideway from time to time so that the rolling elements can recenter themselves relative to the other surface.