Electromagnetic thrust bearing using passive and active magnets, for coupling a rotatable member to a stationary member

摘要

An electromagnetic thrust bearing couples a rotatable member relative to a stationary member utilizing a combination of controllable electromagnets and a radially polarized permanent magnet, each physically associated with the stationary member. In one embodiment the rotatable member comprises a shaft having a pair of axially spaced apart thrust discs fixed thereto. A pair of solenoids are disposed about the rotatable member between the spaced apart thrust discs in oppositely facing relating to axially-facing sides of the thrust discs. The solenoids are capable of generating a controllable electromagnetic field. An arcuate radially polarized permanent magnet is disposed between the solenoids to generate a constant flux high density magnetic field between a solenoid housing and the thrust discs. In a second embodiment, a pair of solenoids are disposed about the rotatable member in facing relating on opposite sides of a single thrust disc. A radially polarized permanent magnet is disposed between the solenoids radially outwardly from the thrust disc for generating a constant flux high density magnetic field between solenoid housings and the thrust disc. A sensor determines the axial positioning of the rotatable member relative to the stationary member and provides input for controlling the positioning of the thrust disc(s) by varying the magnetic flux generated by the solenoids.