Abstract: A magnetic bearing device (1) with an improved vacuum-tight electrical feedthrough through its housing (10) is disclosed. The feedthrough (30) comprises a flat connection element (31) such as a rigid or flexible printed circuit board extending through the wall of the housing (10), preferably all the way along an inner circumference of the housing. The connection element is sealed in a gas-tight manner to the housing. The element preferably has a central opening (36) for receiving the rotor shaft. Connections to the bearing units and sensors may be achieved by flat-ribbon cables (51) or flexprints. The sensors are preferably also implemented as printed sensors. Thus a very compact and cost-efficient magnetic bearing device can be obtained. An alternative embodiment uses a connection element on a side wall of the housing as a feedthrough to the bearing components.

Abstract: A rotor shaft (200) for a magnetic bearing device (1) is disclosed. The shaft comprises an inner portion on whose periphery a plurality of targets (240, 260, 280) separated by spacers (250, 270) are mounted. This is achieved exerting an axial pressing force (F, F?) to the peripheral parts, rather than applying a radial press fit. In this manner, a simplified construction, a higher stiffness and a higher stability at high rotational speed are achieved. Further disclosed is a rotor having a thrust disk (220) whose diameter decreases towards the periphery. This allows to use a larger thrust disk at a given rotational speed.

Abstract: A magnetic bearing device (1) for rotatably supporting a shaft (20) for rotation about a rotation axis (101) is disclosed. The device (1) comprises a first active radial bearing (5), one or more first radial displacement sensors (81), and an axial bearing (6, 7). At least a part of the axial bearing (6, 7) is disposed between the first active radial bearing (5) and the first radial displacement sensors (81) when viewed in an orthogonal projection onto the rotation axis (101). A vacuum pump including the magnetic bearing device (1) and a multiple-sensing unit (8) are also disclosed.

Abstract: A lunar phase display mechanism includes an upper disc which is the lunar display disc and a lower disc mounted concentrically to this disc. One of the discs is mounted so that during normal operation of the mechanism that one disc rotates relative to the other disc, and the other disc is mounted in a stationary position during normal operation of the mechanism while this position can be changed by a rotary motion. The gear train driving the rotating disc allows that the direction of rotation of this disc can be reversed so that the different appearance of the lunar phases at the latitudes of the earth and, in particular, in the northern and southern hemisphere can be taken into account in the display.

Abstract: A method and a controller for controlling a magnetic bearing device, in which a rotor is suspended for rotation around a shaft, are disclosed. Sensor signals are transformed to yield tilt displacement signals (S?x, S?y) which correspond to tilting displacements of the shaft in predetermined directions (x, y). From the tilt displacement signals (S?x, S?y), tilt control signals A?x, A?y) are derived; these are transformed to yield actuator control signals for driving electromagnetic actuators in the magnetic bearing device. According to the invention, tilting displacements for which the tilt vector rotates about the device axis (z) with a first predetermined sense of rotation are controlled separately from tilting displacements for which the tilt direction vector rotates about the device axis (z) with a second sense of rotation opposite to the first predetermined sense of rotation. In this way, control of nutation and precession can be achieved without influence from blade vibrations or shaft bending modes.

Abstract: A magnetic bearing device (1) with an improved vacuum-tight electrical feedthrough through its housing (10) is disclosed. The feedthrough (30) comprises a flat connection element (31) such as a rigid or flexible printed circuit board extending through the wall of the housing (10), preferably all the way along an inner circumference of the housing. The connection element is sealed in a gas-tight manner to the housing. The element preferably has a central opening (36) for receiving the rotor shaft. Connections to the bearing units and sensors may be achieved by flat-ribbon cables (51) or flexprints. The sensors are preferably also implemented as printed sensors. Thus a very compact and cost-efficient magnetic bearing device can be obtained. An alternative embodiment uses a connection element on a side wall of the housing as a feedthrough to the bearing components.

Abstract: A rotor shaft (200) for a magnetic bearing device (1) is disclosed. The shaft comprises an inner portion on whose periphery a plurality of targets (240, 260, 280) separated by spacers (250, 270) are mounted. This is achieved exerting an axial pressing force (F, F?) to the peripheral parts, rather than applying a radial press fit. In this manner, a simplified construction, a higher stiffness and a higher stability at high rotational speed are achieved. Further disclosed is a rotor having a thrust disk (220) whose diameter decreases towards the periphery. This allows to use a larger thrust disk at a given rotational speed.

Abstract: A method and a controller for controlling a magnetic bearing device, in which a rotor is suspended for rotation around a shaft, are disclosed. Sensor signals are transformed to yield tilt displacement signals (S?x, S?y) which correspond to tilting displacements of the shaft in predetermined directions (x, y). From the tilt displacement signals (S?x, S?y), tilt control signals A?x, A?y) are derived; these are transformed to yield actuator control signals for driving electromagnetic actuators in the magnetic bearing device. According to the invention, tilting displacements for which the tilt vector rotates about the device axis (z) with a first predetermined sense of rotation are controlled separately from tilting displacements for which the tilt direction vector rotates about the device axis (z) with a second sense of rotation opposite to the first predetermined sense of rotation. In this way, control of nutation and precession can be achieved without influence from blade vibrations or shaft bending modes.

Abstract: A magnetic bearing device (1) for rotatably supporting a shaft (20) for rotation about a rotation axis (101) is disclosed. The device (1) comprises a first active radial bearing (5), one or more first radial displacement sensors (81), and an axial bearing (6, 7). At least a part of the axial bearing (6, 7) is disposed between the first active radial bearing (5) and the first radial displacement sensors (81) when viewed in an orthogonal projection onto the rotation axis (101). A vacuum pump including the magnetic bearing device (1) and a multiple-sensing unit (8) are also disclosed.

Abstract: The present invention refers to a lunar phase display mechanism including an upper disc which is the lunar display disc and a lower disc mounted concentrically to this disc which is the lunar disc. One of the discs is mounted in such a way that during normal operation of the mechanism it rotates relative to the other disc. This other disc is mounted in such a way that it is in a stationary position during normal operation of the mechanism while this position can be changed by a rotary motion. Alternatively, the gear train driving the rotating disc can be so designed that the direction of rotation of this disc can be reversed. In this way the different appearance of the lunar phases at the latitudes of the earth and in particular in the northern and southern hemisphere can be taken into account in the display.

Abstract: A friction pump, which is equipped with at least one actively controlled magnetic radial bearing, wherein, in order to satisfy the extreme requirements necessary through the tight tolerances of pump elements and an emergency bearing, the high rotational speed and the magnetic support, a special control arrangement for the cooperation of rotor, positional sensors and the magnetic bearing control loop so that a safe operation of the pump at extreme requirements is assured in a simple manner without the use of any additional constructional elements.

Abstract: A venting arrangement for a magnetically supported vacuum pump which has a high speed rotor, wherein the load carrying capacity of the axial magnetic bearing is increased in the course of the venting process by reducing the gap between the axial support disk and the axial magnet in order to carry the additional forces caused by the venting process. In normal operation, the gap is adjusted to an upper limit value.