Ebara Corporation

Other

Atsushi Ooyama

Toshiharu Nakazawa

Toshimitsu Barada

Shinichi Sekiguchi

Hiroyuki Shinozaki

Matsutaro Miyamoto

Masafumi Inoue

Shunichi Aiyoshizawa

Natsushi Suzuki

Shunsuke Yoshioka

Hisashi Nara

Masakazu Komai

A brushless synchronous motor is provided in a simple configuration and at a low cost. The brushless synchronous motor comprises a rotor having salient magnets arranged in a circumferential direction, a stator having driving magnetic poles arranged in the circumferential direction, and an exciting coil wound around each driving magnetic pole, where the rotor is made in a non-circular profile. For example, the rotor may comprise a cylindrical body which has at least one flat surface perpendicular to one magnetic pole direction of the rotor, or a cylindrical body having an elliptic profile with a longer diameter in one magnetic pole direction of the rotor. A detector circuit is associated with each of a predetermined number of exciting coils for outputting a detection signal indicative of the impedance of the exciting coil in accordance with the distance between the driving magnetic pole and rotor, to detect a rotating angle of the rotor.

Brushless synchronous motor and driving control apparatus therefor

An excimer laser apparatus in which deterioration of the laser gas in the laser container can be suppressed, and damage to the magnetic bearings caused by the laser gas can be suppressed, and which can be reduced in size and operated efficiently, and has low power consumption. Each electromagnet (stator) ( - ) of a magnetic bearing ( ) for supporting a rotary shaft ( ) of a circulation fan includes excitation coils. Each of the coils is arranged as one unit by embedding a coil body in a ceramic or glass type hardened material which is non-magnetic and has corrosion resistance against a laser gas. The excitation coils are attached to magnetic poles. Alternatively, coil wires ( ) of a radial magnetic bearing ( ) can be isolated from a corrosive atmosphere by means of a separation wall ( ) while projecting portions of cores ( ) extend through the separation wall ( ) and are exposed toward a magnetic bearing rotor ( ).

Excimer laser apparatus

A magnetic levitation rotating machine is provided which can stably detect the displacement and rotating speed of a rotator and, at the same time, can reduce the size of the whole apparatus, that is, can render the whole apparatus compact. The magnetic levitation rotating machine for supporting a rotator in a levitated state by magnetic force of an electromagnet or a permanent magnet comprises: a position detection plane provided in the rotator and a concave and/or a convex provided in the plane; a displacement sensor provided on the fixed side, for detecting the displacement of the plane including the concave or the convex; and a detection mechanism for detecting the displacement of the rotator and the rotating speed of the rotator from the output of the displacement sensor.

Magnetic levitation rotating machine

A magnetic bearing enables to rotatably support a levitated body non-contactingly disposed in a hermetically sealed container filled with a gaseous process substance of a corrosive nature, while without contaminating the gaseous environment and suffering from corrosion. The magnetic bearing has an electromagnet for supporting a levitated body, a displacement sensor for detecting a levitated position of the levitated body, and a controller for supplying signals and excitation currents to the displacement sensor and the electromagnet through cables. An electromagnet target of the magnetic bearing that generates variations in magnetic fields due to rotation of the levitated body, is constructed of a single piece of ferromagnetic material, and is provided with an electrical insulation structure oriented parallel to magnetic fluxes generated by the electromagnet.

Magnetic bearing and circulation fan apparatus

A magnetic bearing device for use with a motor-combined structure having magnetic bearings supporting a rotatable shaft out of contact therewith and a motor for rotating the rotatable shaft. A common power supply supplies electric power to the magnetic bearings and the motor, and a motor drive power supply limits variations of the electric power supplied to the motor to at most a predetermined level with respect to variations of electric power supplied to the common power supply.

Magnetic bearing device for motor-combined structure

A magnetic bearing device has an object levitated in an arbitrary position between confronting electromagnets. Positional displacement sensors detect a positional displacement of the object. When the electromagnets are successively energized, the object is moved in a mechanically movable maximum range between the electromagnets, and maximum and minimum values of a detected positional displacement signal from the positional displacement sensors are detected. A middle value between the maximum and minimum values is calculated and compared with a threshold level. An adjustment signal is applied to an offset corrector which produces an offset-corrected signal from the detected positional displacement signal, so as to substantially eliminate the difference between the middle value and the threshold level so that the middle value represents a position in which the object is to be levitated between the electromagnets.

Magnetic bearing device

A magnetic bearing device has an electromagnet for levitating an object under electromagnetic forces, a displacement sensor for detecting the displacement of the levitated object, a controller for supplying a signal to the displacement sensor through a cable and a current to the electromagnet through a cable, and a protective plate of nonmagnetic metal material disposed between the displacement sensor and the levitated object. The controller includes a levitation control system having a noise removing filter for preventing an abnormal signal caused by the protective plate from being applied to the displacement sensor.

Growing community of inventors

Fujisawa, Japan

Atsushi Ooyama