A rotatable element is arranged on a supporting member. The element is freely rotatable and displaceable radially by being held in position by two portions attracting each other, said portions being made of magnetic material, and that a plane slot separates the supporting member and the element. The driving of the element can be effected thereby that the element forms or incorporates a rotor in an electromotor, the stator of which is arranged in an area of the supporting member.

A turbomolecular pump including a casing stationary blades arranged in a plurality of stages in the casing axially thereof, rotating blades arranged between the stationary blades and located on an outer periphery of a rotor located in a central portion of the casing, and a bearing device journaling the rotor at its high vacuum and end a low vacuum end. A first permanent magnet of the fixed side having a high Curie point and a second permanent magnet of the rotor side located in juxtaposed relation to the first permanent magnet constitute a magnetic bearing of an attraction type for journaling the rotor at its high vacuum end. A pivot type hydrodynamic bearing or active magnetic bearings journal the rotor at its low vacuum end.

The present invention provides a magnetic rotor bearing for suspending a rotor in a contact-free manner, in particular the rotor of an axial- or radial-centrifugal blood pump, comprising a permanent- and electromagnet arrangement which stabilizes the position of, and suspends the rotor in a stator, in particular a housing, and comprises a circuit arrangement connected to at least one position sensor or to the position sensor operating circuit thereof for the rotor. The rotor is suspended in the stator in a stable, contact-free manner by means of a permanent magnet arrangement except for a single geometric adjusting degree of freedom. The position of the rotor is stabilized only within the geometric adjusting degree of freedom not stabilized by the permanent magnet arrangement, by a permanent magnet arrangement located in the rotor and comprising at least one permanent magnet. The permanent magnet arrangement which co-operates with the electromagnet arrangement comprises at least one permanent magnet of the permanent magnet arrangement provided for suspending the rotor and consists in particular, of the permanent magnets of this permanent magnet arrangement positioned in the rotor. The circuit arrangement is a control circuit stabilizing the position of the rotor, during the absence of external forces, in a position of minimum energy requirement of the electromagnet arrangement.

The gyroscopically stabilized magnetic suspension system constitutes a base assembly which itself constitutes a narrow beam source of electromagnetic energy disposed at substantially the radial center of the base assembly. The base assembly also includes a first toroidal magnet surrounding the source of electromagnetic energy, the first toroidal magnet having a polarity transverse to its toroidal plane. Also provided within the base assembly are first anti-spin magnets disposed beyond the outer toroidal radius of the first toroidal magnet, the anti-spin magnets having the same magnetic axis as the first toroidal magnet but, however, having an opposite polarity thereto. The system also constitutes a suspended assembly itself constituting an electromagnetic energy receiving and converting means, and a motor disposed upon the electromagnetic receiving means and powered thereby, the motor having an axis of rotation and alignment with the axial center of the first toroidal magnet. Also included in the suspended assembly is a second toroidal magnet surrounding the motor and radially connected to the axis of the motor, the second toroidal magnet having its plane disposed parallel to the plane of the first toroidal magnet, the second toroidal magnet having a polarity transverse to its toroidal plane, the polarity opposite to the polarity of the first toroidal magnet, thereby forming a repulsion mode between the first and second toroidal magnets. Also included within the suspended assembly are second anit-spin magnets, thereby forming an attraction mode therebetween adapted to assure a stable perimeter about the rotating, suspended second toroidal magnet.

A centrifugal separator comprises a housing through which extends a spindle on which is mounted a centrifuge rotor. The rotor is mounted on journal bearing bushes that are lubricated by the liquid supplied at pressure to the rotor and the weight of the liquid-filled rotor is carried by magnetic repulsion thrust bearing comprising permanent magnets secured one each to the housing and rotor. The spaced magnets run without contact noise and frictional losses, improving rotational speed available from the supply pressure, and lateral (radial) instability that is inherent between repelling magnets and normally disliked puts a radial bias on the journal bearings which may result in quieter running by inhibiting vibration, particularly when the journal bushes are starved of liquid supply during wind-down. Alternatively or additionally, supply pressure induced lift of the rotor may be borne by a magnetic repulsion thrust bearing. The magnets may be permanent and/or electromagnets.