Patent ID: 6121704
Filing Date: 2000-09-19
Classification: F16C

Abstract:
A magnetic bearing comprising:a rotation shaft;a rotor core mounted on an outer periphery of said rotation shaft;a housing;radial stators fixedly mounted within said housing in opposed relation to the outer periphery of said rotor core, each of said radial stators cooperating with said rotor core to form a magnetic circuit, wherein each of said radial stators comprisesa radial stator core which includes at least one pair of yoke portions on which exciting coils for flowing control current therethrough are wound, respectively, and a body magnetically interconnecting said pair of yoke portions, and,a permanent magnet provided between said body and at least one of said yoke portions;a position sensor for detecting a radial position of said rotation shaft; anda control device responsive to a signal from said position sensor for causing the control current to flow through said exciting coils so as to control the radial position of said rotation shaft,wherein said control device changes the control current so that the control current flowing through said exciting coils becomes zero, when the radial position of said rotation shaft coincides with a balanced position in which the attraction forces of said permanent magnets are balanced, andin a loading state after changing the control current, said control device performs a feedback control to use the balanced position of said rotation shaft as a target position.