Abstract: This invention discloses a magnetic bearing device comprising a rotary member rotatably supported on a supporting member through a magnetic bearing, a free oscillating member which is oscillatable almost coaxially with the rotary member and disposed at a position not being in contact with both supporting member and rotary member, magnetic coupling member for oscillating the free oscillating member and the rotary member together, and a damping member disposed between the free oscillating member and the supporting member.

Abstract: A dynamic pressure bearing with a magnetic fluid sealed therein is reduced in size without degrading the bearing performance and includes a sleeve 5 having an insertion hole 6 axially formed therein fixed in a housing 1, and a pair of pole pieces 9a, 9b disposed with clearances defined between the opposed surfaces of the sleeve 5 and the housing 1. A shaft 7 is inserted in and fixed to the pole pieces 9a, 9b, and is disposed in the insertion hole 6 with a clearance defined therebetween, and a magnetic fluid 15 is sealed in these clearances, thus forming a dynamic pressure bearing assembly. The sleeve 5 is made of nonmagnetic material while the housing 1, shaft 7 and pole pieces 9a, 9b are made of magnetic material. A permanent magnet 2 is interposed therebetween to form magnetic fields in the clearances between the housing 1 and the pole pieces 9a, 9b, thus sealing the magnetic fluid 15 therein.

Abstract: A composite vacuum pump system having first and second vacuum pumps each having its own rotor and drive motor in which the exhaust of the first vacuum pump is removably coupled to the inlet of the second vacuum pump and the first vacuum pump rotor is driven at a constant torque and in which the second vacuum pump has an inlet for permitting the introduction into the pump of a heavy gas for increasing the efficiency of the pumping system.

Abstract: The invention discloses a magnetic bearing device having a rotary main shaft, an armature disk mounted on the rotary main shaft, and a pair of bearing elements disposed on opposite sides in axial direction of the armature disk. Each of bearing elements includes a control coil provided with a pair of pole pieces, wherein a top end of each of the pole pieces is disposed near to the armature disk, and the pole pieces are mounted with a sensor coil at a position nearer to a front end side of the control coil.

Abstract: The invention discloses a magnetic bearing device having a rotary main shaft, an armature disk mounted on the rotary main shaft, and a pair of bearing elements disposed on opposite sides in axial direction of the armature disk of bearing elements includes a permanent magnet provided with a pair of pole pieces, the top ends of each of the pole pieces being disposed near to the armature disk, and a control coil being disposed between said pole pieces at a position nearer to front end side than the control coil.

Abstract: A magnetic bearing device that incorporates a magnetic movable member, a first supporting member having a first coil and a permanent magnet, a second supporting member having a second coil and a permanent magnet, state detecting means for detecting the displacement of the movable member, a first and second wirings for applying current, and switches connected to the first and second wirings for switching the direction of current applied to the first and second coils. The first and second supporting members are located so as to position the movable member between them. During operation, the movable member is magnetically supported so as not to be in contact with either of the supporting members. The first wiring has a first switch circuit connected to a first drive circuit, wherein the bottom end of the first coil is connected between the first switch circuit and the first drive circuit. The first and second wirings are connected in parallel between a dc power source and ground.

Abstract: The present invention relates to an annular sealing member (7) arranged so as to surround the periphery of a working member such as a shaft (10). This sealing member (7) is produced by sticking a sheet (1) of elastic magnet to pole piece-constructing sheets (2,2), and punching the resulting assembly. The annular portion of said sheet (1) of elastic magnet is pressed to be contracted in the direction of thickness and stretched in the radial direction by said punching. As a result, the circumferential portion of the above described annular magnet (8) is dislocated so as to be sunk from the periphery of said annular pole pieces (9,9). Accordingly, the dimensional accuracy of inner and outer circumferences of the sealing member (7) is improved.

Abstract: This invention discloses a magnetic bearing device having a control coil which supports a rotor in a vertical direction and a current controller which increases control current according to an increase in the clearance between the control coil and the rotor. The current controller includes a gain controller which controls the control current with a larger gain when clearance between the control coil and the rotor is less than a certain distance, and with a smaller gain when clearance between the control coil and the rotor is more than that distance.

Abstract: A bearing for a vacuum device having an annular permanent magnet disposed about a rotatable shaft which has one end exposed to low pressure and the other end exposed to atmospheric pressure in which the rotatable shaft has a spherical member formed on the high pressure end for mating with a concave bearing surface having a magnetic fluid interposed therebetween and the rotatable shaft has a plurality of grooves formed thereon for aligning with a plurality of rings formed on an annular pole piece in which a magnetic fluid is disposed between the rings and grooves, which can be formed on the shaft, for providing a high pressure seal.

Abstract: A compact, high-torque electric motor in which one motor element (either the stator or rotor) has magnetic poles whose effective magnetic width is substantially equal and which span equal center angles. The second motor element has a plurality of armature groups, each of which occupies a phase sector of the motor element formed by dividing the total periphery by a natural number. All of the armatures within an armature group are connected electrically in series and excited with a current of one phase (either an alternating current phase or an equivalent phase generated by commutator action). Within on pole group the poles may have equal widths or different widths.