Koyo Seiko Company, Ltd.

Jtekt Corporation

Manabu Taniguchi

Hirochika Ueyama

Yasukata Miyagawa

Hidenobu Nagano

Nobutsuna Motohashi

Toshihiko Daido

Makoto Nohara

Tadashi Fukao

Isao Kuramoto

Yasutaka Miyagawa

Kenji Ooiso

Masayuki Watanabe

Hironori Kameno

Hirochika Kyotani

A first spacer, a second tubular member, and a second spacer are externally fitted and fixed to an outer peripheral surface of a nut. The second tubular member is formed by stacking a plurality of silicon steel plates without any gap, and is arranged between the first spacer and the second spacer axially. The outer diameter of an outer peripheral surface of the second tubular member is made larger than the outer diameter of an outer peripheral surface of the first spacer and the outer diameter of an outer peripheral surface of the second spacer. A detection surface of a first displacement detector is made to radially face a contact portion between the second spacer and the second tubular member, while a detection surface of a second displacement detector is made to radially face a contact portion between the first spacer and the second tubular member.

Rolling bearing device with sensor

If the ambient temperature of a pressure volute measured by a temperature sensor exceeds 0&#xb0; C., a compressor is instantly started at normal operation. If the temperature of the pressure volute measured by the temperature sensor is 0&#xb0; C. or lower, vibration along the axial direction is given to the rotary shaft by way of an axial magnetic bearing. If the vibration amplitude of the thus given vibration exceeds a predetermined value, the compressor is started at normal operation after idle operation. On the other hand, if the vibration amplitude is lower than a predetermined value, the heater is actuated to heat the pressure volute only for a predetermined time. Thereafter, the ambient temperature is detected again, and if the ambient temperature exceeds 0&#xb0; C., the compressor is started.

Centrifugal air compressor

A rolling bearing device with a sensor includes a rotational component estimator that extracts a rotational synchronization component included in the rotation of an inner shaft relative to an outer ring from each of a signal output by a first displacement detector and a signal output by a second displacement detector. The rotational component estimator performs rotational operation and integration operation.

A DSP (Digital Signal Processor) () controls at least a magnetic bearing (), and compares the accumulated actual work time of a managed component counted by a counter () with a preset maintenance time. The DSP () outputs a signal instructing the start of the maintenance operation of the managed component, based on the comparison result.

Magnetic bearing control device with counter for timed maintenance

A magnetic bearing device includes a pair of electromagnets holding a rotary body at opposite sides thereof in the direction of each of control axes, a detector for detecting the position of the rotary body, and an electromagnet controller having an integral operation unit for controlling the electromagnets based on the result of detection of the position. The electromagnet controller sets as a target levitated position of the rotary body the position of the rotary body corresponding to the median of an integral output of the integral operation unit when the rotary body is magnetically levitated in the vicinity of one of limit positions in the direction of the control axis determined by protective bearings and an integral output of the unit when the rotary body is magnetically levitated in the vicinity of the other limit position.

Magnetic bearing device

The magnetic bearing control device ( ) has a motor drive circuit ( ) provided with an inverter ( ) for driving the motor ( ) capable of generating an electric power, the inverter being controlled by an inverter control circuit ( ), and an over-speed detection circuit ( ) for detecting the number of revolutions of the rotor ( ) that is being rotated by the motor ( ), the rotor being supported in non-contact manner by a magnetic bearing ( ). When the over-speed detection circuit ( ) detects that the rotor ( ) is being rotated at a preset number of revolutions or more, the motor drive circuit ( ) performs a switching operation of a switch portion provided in the motor drive circuit ( ) to separate the inverter ( ) from the motor ( ) and connect the motor ( ) to a regenerative circuit ( ), whereby the magnetic bearing ( ) is driven and controlled, employing a regenerative electric power of the motor ( ).

Magnetic bearing control device

A magnetic bearing device comprises a machine main body having position sensors for detecting the position of a rotary body and magnetic bearings for magnetically contactlessly supporting the rotary body, a controller for controlling the magnetic bearings based on the signals from the position sensors, a data processing computer installed at a location away from the controller, and modems for connecting the controller to the computer by communication lines.

Remote bearing device with remote diagnostic capability

System for controlling plural magnetic bearing devices from a remote location

A machine tool comprises a spindle unit for raising a spindle on which a cutting tool is mounted by a magnetic force and supporting the spindle. The spindle unit carries out feedback control so as to maintain the spindle in its target position in the radial direction. A feeder for feeding the cutting tool to a work comprises a servo motor for moving the spindle unit relatively to the work. A feeding controller for controlling a feeding operation of the feeder controls the speed of rotation of the servo motor on the basis of feed speed data stored in a memory. The feed speed data comprises a first feed speed corresponding to the time when the cutting tool cuts through an end surface of the work crossing the direction of feeding and a second feed speed corresponding to the time of normal working and higher than the first feed speed.

Machine tool

Magnetic bearing spindle device

A magnetic bearing spindle device for machine tools comprises a spindle for mounting a tool element as changeably attached to a forward end thereof, a plurality of controllable magnetic bearings for contactlessly supporting the spindle, an electric motor for rotating the spindle as contactlessly supported by the magnetic bearings, a draw bar inserted through the spindle and axially movable for unclamping and clamping the tool element, state sensor switches for detecting the axial position of the draw bar to detect a state of having no tool element, an unclamping state or a clamping state, and a control unit for controlling the support of the spindle by the magnetic bearings and the rotation of the spindle by the motor based on the result of detection by the switches.

Magnetic bearing spindle device for machine tools

A magnetic spindle device for machine tools has a spindle contactlessly supportable by a plurality of controllable magnetic bearings for mounting thereon a tool element which is automatically changeable for a tool element of different kind. The spindle device comprises a device for measuring the weight of the tool element by measuring the exciting currents of the magnetic bearing, and a device for changing over the control characteristics of the magnetic bearings based on the measured weight of the tool element.

A magnetic bearing apparatus comprises a pair of radial magnetic bearings arranged on both sides in the axial direction of an axial magnetic bearing. A pair of first touchdown bearings are arranged at both ends of a spindle. Annular slide bearings are mounted as second touchdown bearings for receiving the spindle on inner peripheral parts of electromagnets in the axial magnetic bearing. The radial internal clearance between the slide bearing and the spindle is larger than the radial internal clearance between the first touchdown bearings and the spindle and is smaller than the radial internal clearance between the radial magnetic bearings and the spindle. Even if a central part of the spindle is deflected at the time of emergency stop, both the first touchdown bearings and the slide bearings receive the spindle, so that the load on the first touchdown bearings can be reduced.

Magnetic bearing apparatus

In a torque sensor, an oscillating voltage from an oscillator is applied to a torque detecting coil and a temperature compensating coil, and voltages from the torque detecting coil and the temperature compensating coil are input to a differential amplifier which produces a differential-amplified voltage for detection of a torque, wherein when the oscillator has ceased producing the oscillating voltage, a prescribed voltage is applied to a circuit through which the voltage from the torque detecting coil or the temperature compensating coil is input to the differential amplifier, thereby causing the differential amplifier to output a voltage shifted outside a prescribed range and thus detecting a failure of the oscillator.

Torque sensor

A torque sensor which includes two cylinders fixed to two shafts connected with each other through a torsion bar. The magnetic coupling state of the two cylinders is made variable corresponding to relative rotations of the two shafts. The magnetic coupling state thereof is detected by a coil impedance, which is indicative of a torque acting on the shafts. The two cylinders form at the opposite end edges thereof teeth provided with cutouts disposed circumferentially of the cylinders and are opposite to each other at portions of about half a width of each tooth. The two shafts are regulated by rotation so as to not put the teeth of the cylinders completely opposite or non-opposite to each other.

Growing community of inventors

Kashihara, Japan

Manabu Taniguchi