| 摘要 |
A magnetic bearing for supporting in suspension a linear armature member (20) includes an elongated cylindrical housing (18) having two sets of U-shaped stationary electromagnets (101, 121, 141, 161 and 102, 122, 142, 162) and position sensors (481, 501 and 482, 502) respectively located at each end of the housing (18). Each set of electromagnets preferably consists of four electromagnet assemblies (101, 121, 141, 161 and 102, 122, 142, 162) located 90 DEG apart around the periphery of the housing (18) and are operable to generate four orthogonal magnetic fields within the housing (18). Each set of position sensors (481, 501 and 482, 502) are aligned with the electromagnets to define two orthogonal horizontal (X) and vertical (Y) axes from which signals proportional to orthogonal shaft displacement are provided. These signals are fed to four separate circuit means, two for each X and Y axis which are adapted to provide signals proportional to shaft positional displacement and velocity within the housing which are utilised to generate respective control signals of the proper amplitude and direction to energise the coil windings (321, 341, 361, 381 and 322, 342, 362, 382) for radially centering the shaft (20) within the housing (18) while maintaining a predetermined stiffness and dampening characteristic. Also a bumper magnet assembly comprising an axially magnetised magnet situated between a pair of repulsing axially magnetised magnets is included for dampening any axial displacement of the armature member (20). |
