Patent ID: 7274123
Filing Date: 2007-09-25
Classification: F16C

Abstract:
1. Axial magnetic bearing apparatus in which a rotary disc made of a magnetic material is fixedly attached to a rotating shaft, while a pair of electromagnetic stators in each of which a ring-like electromagnetic coil for generating magnetomotive force is inserted into a coil slot are fixed to casings respectively so as to be located on opposite sides of said rotary disc with suitable very small distances, and on the basis of an output signal of a displacement sensor for measuring axial displacement of said rotating shaft, magnetic attraction force is made to act between said rotary disc and each of said electromagnetic stators so as to bear said rotating shaft in a target position distant from said electromagnetic stators and in non-contact therewith, said axial magnetic bearing apparatus being characterized in that an outer diameter of each of said electromagnetic stators is formed to be substantially as large as an outer diameter of said rotary disc, and a ring made of a non-magnetic material having a radial thickness large enough to form a layer with large magneto-resistance is interposed between an outer circumferential portion of each of said electromagnetic stators and an inner circumferential portion of corresponding one of said casings to which said electromagnetic stator is attached.