FULL LEVITATION BEARING SYSTEM WITH IMPROVED PASSIVE RADIAL MAGNETIC BEARINGS

摘要

A full levitation magnetic bearing system for support of a rotating body (71), such as a flywheel (92), about an axis of rotation includes passive radial magnetic bearings (70) that generate passive radial centering forces to counteract displacements of the rotating body (71) from its axis of rotation during rotation, and an axial actuator (102) for stabilizing the axial position of the rotating body (71). The passive radial magnetic bearings (70) include multiple concentric, radially spaced apart, axially magnetized ring magnets (73) on a stationary stator (72) and magnetically co-operating concentric pole rings (74) on a ferromagnetic end portion of a rotor (71). The rotor pole rings (74) are axially aligned with the magnet rings (73) when the rotor (71) is radially centered on the stator (72). Magnetic flux from the permanent magnet rings (73) passes directly across the airgap (78) between the axially facing surfaces of the magnet rings (73) and the rotor pole rings (74) and through rotating ferromagnetic section of the rotor (71), thereby generating both an axial attractive force and a passive radial centering force from the pole rings (74) tending to align with the stationary magnetized rings (73).