Seiko Seiki Kabushiki Kaisha

Edwards Japan Limited

Societe De Mecanique Magnetique

Shinichi Nomura

Toshiharu Kogure

Katsura Tomotaki

Osamu Hanami

Shinji Koyano

Ulrich Schroder

Ikuo Muto

Koichi Suda

Heung Chul Shin

Akira Inoue

Yuichi Kinoshita

Provided are a compact and low-cost motor driver circuit capable of achieving an appropriate brake time and restraining heat generated by a regenerative resistance within a specific temperature range without employing a regenerative resistance having a greater capacity, a heat sink, or a FAN generating a larger volume of air, and a vacuum pump having the motor driver circuit. Regenerative current is controlled so that a speed characteristic gradually approaches inclination 'a' from inclination 'b' depending on the motor speed in the initial stage of regeneration. In addition, a limit is set not to pass further current when the regenerative current reaches a maximum brake current value I. As stated above, when the motor is braked, control is performed so that the initial brake current value at the maximum rated speed is set low and the brake current is increased as the rotational speed decelerates.

Motor driver circuit and vacuum pump having the motor driver circuit

A communication abnormality detecting/coping device and a vacuum pump remote monitor control device are provided, which are capable of detecting the presence/absence of an abnormality in data communication and reducing an influence of the abnormality on a system device when detecting the abnormality. An operation acknowledge message,is transmitted to a system device (,) from a turbo-molecular pump control device (,) in Step,A reply message (,) indicative of the reception of the operation acknowledgement message,by the system device (,) is transmitted to the turbo-molecular pump control device (,) in Step,In Step,an elapsed period of from a time at which the operation acknowledgement message (,) is transmitted to a time at which a reply message (,) is received is measured, and if the elapsed period exceeds the preset period, the abnormality in the communication system is warned in Step

Communication abnormality detecting/coping device and vacuum pump remote monitor control device

To keep a temperature of an interior of an automotive vehicle at least at a level of an external atmospheric temperature even if the vehicle is parked with an engine being stopped for a long time, an automotive air-conditioning apparatus is composed of a cooling device 12 to be controlled by a controller 13, a pre-cooling device 20 for pre-cooling the interior of the vehicle, and a sub-controller 18 for controlling the pre-cooling device. The pre-cooling device is composed of a cooling thermoelectric element module 22, a ventilation fan 23, a solar battery 21 and a pre-cooling storage battery 24 charged by the solar battery. The sub-controller always operates the pre-cooling device 20 while the vehicle is stopped with the engine being stopped and starts the pre-cooling device 20, for example, one hour prior to a time when the vehicle starts to movement during parking for a long time in an interior parking lot or the like with the engine being stopped so that the temperature of the interior of the vehicle is kept at a temperature that does not so much exceed a set temperature, i.e., at least at the level of the external atmospheric temperature, until the engine is started.

Automotive air-conditioning apparatus

A temperature adjusting device has an air-tight container. A thermoelectric element is disposed in the air-tight container and has first and second opposite surfaces each capable of radiating and absorbing heat through a Peltier effect. A first heat exchanger is disposed in the air-tight container for performing heat exchange between a thermally conductive first medium and the first surface of the thermoelectric element. A tank is disposed in the air-tight container and is connected to an inlet side of the first heat exchanger for storing the first medium. A second heat exchanger is disposed in the air-tight container for performing heat exchange between a thermally conductive second medium and the second surface of the thermoelectric element. A pump circulates the first medium through the first heat exchanger. A temperature sensor detects a temperature of the first medium circulated by the pump. A controller controls an electric current supplied to the thermoelectric element so that a temperature detected by the temperature sensor becomes equal to a preselected temperature value.

Temperature adjusting device

A positioning system comprises a feeding mechanism having three or more feeding units disposed in a moving direction of a moving body. Each of the feeding units has first and second moving elements for clamping and unclamping the moving body, feeding the moving body in the moving direction from an initial position to a target position, and returning the moving body to the initial position. A memory device stores preselected phase and amplitude values of the first and second moving elements. A calculating device calculates phase and amplitude command values for the first and second moving elements based on the phase and amplitude values stored in the memory device. An output device outputs driving command values to the first and second moving elements based on the calculation result of the calculating device. A control device controls the feeding units to clamp the moving body by all of the feeding units after the moving body has been moved to the target position.

Super-precision positioning system

A magnetic bearing device comprises a rotor, electromagnets, radial direction displacement sensors, and a control circuit for controlling an exciting current of the electromagnets in accordance with a signal from the radial direction displacement sensors to magnetically levitate the rotor. The control circuit comprises a position detecting circuit, a calculator, a PID operating part, a phase inverter and power amplifiers. A CPU analyzes the displacement of the rotor at the time of rotation on the basis of a sensor signal issued from the position detecting circuit to supply a correction signal obtained as a result of analysis to the calculator. A magnetic force is thus generated which offsets the oscillation of the rotor for each of the frequency components and is supplied to the electromagnets. The magnetic bearing device is capable of inhibiting displacement components of the rotor other than a first order component in the rotation frequency of the rotor.

Magnetic bearing device

An electrolytic combined processing machine includes a grinding wheel spaced apart from and facing a workpiece, a current switching circuit for switching a coarse grinding to a fine grinding of the workpiece by the grinding wheel, and an infeed switching circuit for switching the infeed speed of an infeed table which allows the grinding wheel to relatively approach the workpiece. The switching operation is based on a measurement result obtained from a size measuring unit which measures a processing amount of the workpiece. During fine grinding, the infeed speed of the grinding wheel is the same as the speed of a passivation coating film generated on the workpiece. Workpieces, particularly of brittle materials, can be processed in a state of less processing distortion with improved surface roughness, flatness and efficiency.

Electrolytic combined processing machine

A magnetic disk inspection apparatus for recording and reproducing inspection signals onto and from each track on a magnetic disk, in which the inspection signals are recorded and reproduced automatically without a manual operation onto and from the magnetic disk, the maximum value is detected from the reproduction signals on the basis of the sampling signal, the average value of the maximum values is calculated for each sector, the difference between the average values in the same sector number of the adjacent tracks is determined, the change ratio based on this difference is calculated and quality of the magnetic disk is judged on the basis of this change ratio.

Quality inspecting method and apparatus for detecting defects in

A magnetic disk inspection apparatus for inspecting protuberance on a surface of the magnetic disk. The apparatus includes an inspection head detecting the protuberance by a piezosensor, and rotating speed control circuit controlling a rotating speed of the magnetic disk held by a rotary holder member. The rotating speed control circuit generates a different speed increasing rate for each of concentric zones formed by dividing into a plurality of sections in a radial direction of the magnetic disk to keep a floating height of the inspection head in a predetermined constant value.

Magnetic disk inspection apparatus

The present invention provides an inspection apparatus for inspecting an object such as an information storage medium or an information recording/reproducing head under set inspection conditions, which comprises: a sensor for identifying the type of object set for inspection by its size, and automatic inspection condition setting means for automatically setting the inspection conditions for the object to be inspected which are associated with the type identified.

Inspection apparatus

A stepping motor control apparatus comprises current computing means for computing a motor-coil exciting current corresponding to the holding position from a predetermined wave form pattern; micro step driving means for driving the stepping motor toward the final holding position through a micro step transfer distance shorter than a regular step transfer interval by exciting the motor-coil by application of the exciting current obtained from the computing means; and acceleration control means for controlling the stepping motor acceleration by switching on and/or off the exciting current of the motor-coil in accordance with an acceleration signal.

Growing community of inventors

Narashino, Japan

Shinichi Nomura