An electric motor system includes a rotary shaft having an axis line displaceable relative to a rotation center, a magnetic bearing for supporting the rotary shaft, a permanent magnet mounted on the rotary shaft and having a plurality of magnetic poles arranged in a circumferential direction around the axis line of the rotary shaft, three detection elements arranged in the circumferential direction around the rotation center for detecting a magnetic flux generated from the permanent magnet, and a coordinate detection section for determining coordinates of the axis line of the rotary shaft based on output values of two detection elements selected out of the three detection elements in accordance with a rotation angle of the rotary shaft.

A method for manufacturing a solenoid-armature ram composite and a corresponding solenoid-armature ram composite for a linear actuator which has a stator with a coil that can be fed with electrical current for producing an electromagnetic field and a single-part or multi-part solenoid armature movable along a longitudinal axis of the coil and a ram connected with the solenoid armature, provides that the solenoid armature surrounds the ram in a ring shape and a gap between the ram and the solenoid armature is cast with a casting material.

A magnetic bearing (20) comprises: a rotor (22) to be supported for rotation about an axis (502); a stator (24) extending from a first end (30) to a second end (32) and comprising: one or more first permanent magnets (50); one or more second permanent magnets (52) of polarity substantially opposite to a polarity of the one or more first permanent magnets; and laminate teeth, encircled by radial windings (36A, 36B), axially between and extending radially inward of the one or more first permanent magnets on one side and the one or more second permanent magnets on the other side. The rotor comprises: one or more third permanent magnets (150); and one or more fourth permanent magnets (152) axially spaced from the one or more third permanent magnets.

A magnetic bearing (20; 220; 320) comprises: a rotor (22; 322) to be supported for rotation about an axis (502); a stator (24; 224) extending from a first end (30) to a second end (32) and comprising: one or more first permanent magnets (50); one or more second permanent magnets (52) axially spaced from the one or more first permanent magnets; one or more intermediate permanent magnets (60; 230; 232) axially between the one or more first permanent magnets and one or more second permanent magnets; laminate teeth (64A, 64B, 66A, 66B) radially inward of the one or more intermediate permanent magnets; and a plurality of radial windings (34A, 34B, 36A, 36B), respectively encircling a respective associated tooth of the plurality of teeth.

An active magnetic rotor-bearing assembly for conveying a fluid comprising a rotor assembly is disclosed and a bearing assembly for contactless bearing the rotor assembly, where the bearing assembly comprises an even number of electromagnetic units arranged around a central structure each comprising a first salient established by a magnetic material and a permanent magnet providing a first magnetic pole and a coil around the salient, further comprises an inter-yoke with inter-yoke portions connected to the first salient of each electromagnetic unit and being separated from each other by structure spacers, providing a closed first magnetic flux passing the rotor assembly applying a first attractive force further comprising a position stabilizing portion perpendicular to the first attractive force on the rotor-assembly and the coils providing an electromagnetic flux between each first salient and the rotor assembly for applying adaptable axial force and/or tilting torque to the rotor assembly.

A magnetic bearing (20) comprises: a rotor (22) to be supported for rotation about an axis (502); a stator (24) extending from a first end (30) to a second end (32) and comprising: one or more first permanent magnets (50); one or more second permanent magnets (52) of polarity substantially opposite to a polarity of the one or more first permanent magnets; and laminate teeth, encircled by radial windings (36A, 36B), axially between and extending radially inward of the one or more first permanent magnets on one side and the one or more second permanent magnets on the other side. The rotor comprises: one or more third permanent magnets (150); and one or more fourth permanent magnets (152) axially spaced from the one or more third permanent magnets.

A magnetic bearing (20) comprises: a rotor (22) to be supported for rotation about an axis (502); a stator (24) extending from a first end (30) to a second end (32) and comprising: one or more first permanent magnets (110); one or more second permanent magnets (112) of polarity substantially opposite to a polarity of the one or more first permanent magnets; at least three radial windings (40,42,44,46); a first axial winding (34); a second axial winding (36); a first end pole (120); and a second end pole (122).

A magnetic bearing device comprises a radial magnetic bearing configured to magnetically levitate and support a rotor shaft in a radial direction; an axial magnetic bearing configured to magnetically levitate and support, in an axial direction, a rotor disc rotatable together with the rotor shaft; and an axial displacement sensor disposed on a surface of an electromagnet core of the axial magnetic bearing facing the rotor disc and configured to detect axial displacement of the rotor disc.

Provided are a vacuum pump, a magnetic bearing device, and a rotor that suppress swinging and vibration of a rotor. A vacuum pump includes, in the following order in the exhaust direction of a gas, the center of gravity of a rotor, an active radial bearing that supports the rotor in the radial direction in a non-contact manner by using a magnetic force, and a passive radial bearing that supports the rotor in the radial direction in a non-contact manner using a magnetic force.

A magnetic bearing contactlessly supporting a rotor by magnetic force includes: a bearing rotor member made of a magnetic material; and a bearing stator member arranged around bearing rotor member. The bearing stator member includes a core made of a magnetic material and a coil wound around the core. A longitudinal cross-sectional shape of the core has a first part extending in a first direction orthogonal to a direction opposed to the bearing rotor member and wound around with the coil, a pair of second parts extending from both end portions in the first direction of first part to the bearing rotor member side and subsequently extending in a direction approaching each other in the first direction, and a pair of third parts extending from respective distal end portions of the pair of second parts toward the bearing rotor member side. The bearing rotor member also includes a permanent magnet.