Electromagnetic thrust bearing 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 arcuately shaped constant flux permanent magnets and controllable electromagnets, each physically associated with the stationary member. More particularly, the rotatable member comprises a shaft having a radially extending thrust disc fixed thereto. A pair of solenoids are disposed about the rotatable member in facing relation on opposite sides of the thrust disc. The facing solenoids are capable of generating a controllable electromagnetic field. A constant flux high density magnetic field is generated between the solenoid housings and the thrust disc by a pair of axially polarized arcuately shaped permanent magnets disposed on each side of the thrust disc. Each pair of permanent magnets has an inner magnet and an outer magnet radially separated from one another. Each permanent magnet is linked magnetically to the adjacent solenoid housing by respective ferromagnetic pole pieces. 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 by varying the magnetic flux generated by the solenoids.