Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Denki K.k.

Yoshihide Kinbara

Hajime Ogawa

Shinji Sato

Hisao Tanaka

Takashi Yuzawa

Naoki Muramatsu

Yoshio Ozaki

Akaru Usui

Atsushi Taneda

Morihisa Nishikawa

Kazuhiko Uemoto

In an electromagnetic contactorfor passing a current through an electromagnetfrom a power sourceand moving a movable corefrom a first position in which a gap to a fixed coreis wide to a second position in which the gap is narrow by electromagnetic force and opening or closing a contact, there is provided an attraction force control partfor passing a strong acceleration current Ethrough the electromagnetfor a predetermined time so that acceleration in the second position of the movable corebecomes a predetermined value and passing a suction current Ethrough the electromagnetin substantially the second position.

Electromagnetic contactor

A scraping apparatus in which a scraping process is performed on a surface of a work to be machined to form recesses thereon by converging a laser beam outputted from a laser oscillator by a converging lens and irradiating the converged laser beam onto the work relatively moving to the laser beam for removing some portions by being melted or evaporated from the surface thereof.

Scraping method

A rolling bearing of the present invention constructs a current passing structure by fixing a current passing plate fixed to an outer peripheral portion of an inner ring and a current passing sealing plate having a U-shaped sectional shape, whose opening portion is directed inwardly, to the inside of an outer ring so as to surround a current passing plate on a side surface of this U-shaped sectional shape and then sealing a conductive grease into the inside of this U-shaped sectional shape.

Antifriction bearing

A discharge pulse generator for supplying power between a pair of electrodes ( and ), comprises a distribution constant line ( ) of a predetermined length being connected at one termination to the electrodes ( and ), charging means ( ) being connected to the distribution constant line ( ) for charging the capacitance of the distribution constant line ( ), rectification means ( ) being connected to an opposite termination of the above-mentioned distribution constant line ( ) in a direction in which no current flows relative to voltage of the above-mentioned charging means ( ), and a resistor ( ) being connected in series to the above-mentioned rectification means ( ) and having a resistance value equal to the characteristic impedance of the above-mentioned distribution constant line ( ). For example, to use the discharge pulse generator for electric discharge machining, a workpiece can be worked on with higher accuracy and higher quality at higher speed.

Discharge pulse generator

A power source control apparatus has a constant current circuit and plural laser diodes. A first switching circuit is turned off, while a second switching element is turned on, before a laser beam is output from the laser diodes. Then, there is formed a circulating circuit for supplying electricity to a current controlling switching element and a reactor. At this time, a fixed constant current is supplied to the reactor, while kept at a command value. When a laser output command signal is generated, the first switching element is turned on, while the second switching element is turned off. Then, there is formed a circuit for supplying electricity to the current controlling switching element, reactor and laser diodes. At this time, influence of inductance of the reactor can be ignored. Thus, a constant current pulse with a steep rise and fall is supplied to the laser diodes.

Power source control apparatus for laser diode

A power supply unit provides therein a first power unit outputting a first excitation amplitude and operating from rising of a reference pulse signal outputted from a reference oscillator until rising of a first time delay signal having a time delay to the reference pulse signal, a second power unit outputting a second excitation amplitude and operating from rising of the first time delay signal until rising of a second time delay signal having a time delay to the first time delay signal, and a third power unit outputting a third excitation amplitude and operating from rising of the second time delay signal until falling of the first time delay signal, and supplies output by synthesizing output from the first power unit, second power unit and the third power unit to the exciting unit.

Control method of exciting a pulse laser and power supply unit for exciting a pulse laser

A power source control apparatus has a constant current circuit and plural laser diodes. Switching elements are connected in parallel between anodes and cathodes of the laser diodes. Forward voltage drop of the switching elements is set lower than forward voltage drop of the laser diodes. When constant current output from the constant current circuit flows through the laser diodes, the switching element either short-circuits or opens the anode and cathode of the laser diode. Thus, current path is switched vise versa.

An electric discharge machine for generating electric discharge in a space between an electrode and a work to machine the work, in which saturable reactors are inserted into feeder lines each for feeding a machining power from a machining power source to the electrode as well as to the work and each of the saturable reactors is excited by a current reverse to a discharge current.

Electric discharge machine

An electric discharge machine is equipped with a current detector 410 for causing an auxiliary discharge circuit 200 to be operated and for detecting that a value of an auxiliary current exceeds a predetermined value; a timer 401 having first setting time longer than time defined until flowing of charge current into the auxiliary current is ended; a timer 403 having second setting time defined after a detection is made that the value of the auxiliary current exceeds the predetermined value until the discharge operation is brought into a stable condition after the first setting time; an operation means 470 for stopping the auxiliary discharge circuit 200 after the second setting time has passed, and for causing the main discharge circuit 300 to be operated during preselected time; and a timer 440 having a setting time longer than such time that after the operation means causes the main discharge circuit to be operated during the preselected time, the current value of the main discharge circuit 300 becomes lower than, or equal to a predetermined value; and for producing an end signal after this setting time has passed.

A magnetic contactor including a phase switch and a phase angle adjusting device for adjusting the phase angle at which the phase switch provides for the supply of voltage to an electromagnet to energize the electromagnet. The phase angle is adjusted, via the phase angle adjusting device, to a position at which a collision velocity of a movable iron core against a fixed iron core of the magnetic contactor is lowered, and where the impact of the movable iron core is reduced to increase the life of the magnetic contactor.

Magnetic contactor having phase angle adjuster

In a power supply apparatus of an electrical discharge machine, a power supply high in efficiency and small in current ripple is provided to achieve a power supply reduced in size and price. In addition, a switching power supply system is used jointly to generate an optional waveform. A first switching device is switched on/off in an optional cycle under the control of a current command value signal corresponding to the waveform shape of a current pulse to be supplied to a machining gap, whereby an optional shape of current pulse is supplied to the machining gap and a current component which compensates for a current ripple generated by said switching at the time of supplying said current is superimposed on said optional shape of current pulse and is supplied to the machining gap.

Method and apparatus for controlling the power supply for electrical

An electric power-source apparatus for a discharge processing machine comprises a constant-current supply section having a first switching element and an output-current interrupting section having a second switching element. Processing power is supplied to a location between an electrode and a workpiece which are arranged within a dielectric. A comparator compares output-current detecting values from the constant-current supply section, and upper-limit addition voltage and lower-end subtraction voltage of an output-current command section with each other, respectively. Output current from the constant-current supply section is controlled by a first flip flop. A timer section is controlled by a discharge command from a discharge command section and a discharge-time command section. The output-current interrupting section is controlled by the comparator, the timer section and a second flip flop.

Electric power-source apparatus for discharge processing machine

A snubber circuit for a DC chopper-type power converter having a power supply and a switching circuit connected to a load, the switching circuit comprising a switch and a diode, and the snubber circuit having a combination of capacitances, diodes and inductances to direct and store currents and voltages during the ON/OFF operation of the switch. A surge current and voltage suppressing capability is provided by the series connection of an inductor or reactor between the switch and the diode in the switching circuit, with the load circuit being connected at either end of the inductor or reactor element. Further, the snubber may be arranged as two parallel series circuits, one containing the switch, inductor and diode and another containing additional diodes and inductance. Resonance suppression may be provided by the further addition of a capacitor between the inductor in the first series circuit and the diodes in the second series circuit. The power converter may be any of a voltage-raising chopper type, a voltage dropping chopper type, a voltage reversible chopper type, a CUK type and a forward type, and may be embodied as a half-bridge inverter.

Snubber circuit for power converter

A waveform control device for an electrical discharge machine apparatus which supplies current pulses to the gap between an electrode and a workpiece for machining of the workpiece. A first D.C. source, which supplies at least a part of a voltage that is applied across the gap, is connected in parallel with first and second circuits comprising a series connection of a switch and a diode. Connected between a first and second series circuit is a switched conductive circuit which, together with an auxiliary D.C. source, maintains the current flow at a base current level. Control of operation of the switches in the first and second circuits permit a controlled discharge of current across the gap while permitting the output voltage to be clamped at a safe level. A plurality of inductive circuits may be used to provide selectivity, where the inductances are different and to provide further control of the discharge current shape. A variable inductance, whose value is proportional to the output peak current, may be used to control current ripple.

Waveform control device for electrical discharge machining apparatus

An inverter device using semiconductor current control elements is disclosed in which a parallel circuit of a current limiting circuit composed of a reactor and a voltage spike absorbing circuit composed of a series circuit of a constant voltage element and a diode is connected in series with each of the semiconductor current control elements to prevent excess current flow through the latter.

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Tokyo, Japan

Yoshihide Kinbara