Magnetic suspension apparatus

Abstract

A magnetic suspension system for efficiently supporting a rotor of relatively large radius and high available moment of inertia includes concentric stator and rotor elements spaced apart by narrow gaps of relatively large diameter and very small axial extent. A pair of spaced discs in the stator are oppositely polarized by a permanent magnet, their peripheral magnetic field strength being selectively augmented or diminished in predetermined sectors by electromagnet windings thereon. The rotor includes narrow ring faces juxtaposed to said discs, a permanent magnetic polarization being provided between the narrow ring faces. Means are provided for varying the relative electromagnetic contributions in the different sectors to maintain stability of rotor positioning with minimized electric power. SU The present invention relates to magnetic suspension systems. Magnetic suspension systems have been described in various prior patents including, inter alia, the following U.S. patents to Joseph Lyman, assigned to the assignee of the present invention: ______________________________________ Patent No. Issued ______________________________________ 3,428,371 February 18, 1969 3,473,852 October 21, 1969 3,860,300 January 14, 1975 ______________________________________ The present invention is directed to improved magnetic suspension systems for affording advantages as to manufacturing along with enhanced control of the suspended body. A plurality of like bearing elements may be constructed for inclusion in one end product for stable reference purposes or other purposes having stringent requirements as to the bearings. Furthermore, high bearing efficiency and control of alignment are to be provided without excessive mass of the suspension means. An object of this invention is to provide an improved magnetic suspension system providing great restoring force in response to the axial component of relative displacement between a stator portion and a rotor portion, providing great restoring force in response to any relative cocking (i.e. departure from parallelism) between a stator portion and a rotor portion, and providing efficient and effective control of the force components perpendicular to the axis of the stator portion to provide the optimum positioning of the rotor axis relative to the stator axis to meet the various conditions which may be encountered. A further object of this invention is to provide an improved magnetic suspension system which provides the aforementioned benefits without excessive drag from eddy currents induced in the rotor. Yet a further object is to provide an improved magnetic suspension system consisting of plural component wafers each having the aformentioned attributes. In order to meet these objects, there are provided in the present invention water-like bearing units each of relatively large diameter in contrast to its thickness, wherein the magnetic gaps at which the suspension forces are generated are formed at radii approaching the overall maximum radius of a wafer unit. In a preferred version, the rotor portion is arranged not within but rather surrounding the stator portion of the bearing wafer unit. In at least one of the two portions of one wafer unit (the stator portion or the rotor portion) an axially polarized annular magnet is provided between two pole pieces which provide parallel narrow ring-like poles to coact with a pair of narrow ring-like poles of the cooperating portion (the rotor portion or the stator portion) of the wafer. In the preferred construction an axially polarized permanent magnet is included in each of the two portions (the stator and the rotor) of the wafer, the axial sensing of the rotor magnet being opposite to that of the stator magnet. The result in any event is magnetic flux directed substantially radially outward at the annular gap at one side of the wafer unit and magnetic flux directed substantially radially inward at the annular gap at the opposite side of the wafer unit.

Dependencies are inferred from the claim text.