KR830000924B1 - Power supply device of electrical processing machine - Google Patents

Abstract

The input terminal can be connected with an AC source of a low frequency without equipping a transformer. The rectifier converts the AC to the DC, and is connected with the AC source. The pulse apparatus generates a power of higher frequency than the constant AC frequency by converting the DC into a pulse. The power of high frequency converts a voltage into a desired level in the high frequency transformer. Non-linear series electricity of a pulse intermediation function generates a pulse from the high frequency power of the desired level in the electrical processing machine.

Description

Power supply of electric processor

1 is a circuit diagram of an embodiment according to the present invention.

2-4 are circuit diagrams of embodiments of some of the circuits shown in FIG.

5 is a circuit diagram of an AC-DC-high frequency-DC converter in accordance with the present invention operating in response to a state of an electrical processing gap.

6 shows waveforms appearing in various parts of the AC-DC-high frequency-DC converter circuit according to the present invention for a separate mode of electrodischarge machining operation.

FIG. 7 is a circuit diagram illustrating another embodiment of an AC-DC-high frequency-DC converter circuit that causes a high voltage gap-break pulse to overlap on a low voltage overhead pulse.

8 to 10 are circuit diagrams showing modifications of the circuit shown in FIG.

11-13 are circuit diagrams showing AC-DC-high frequency-DC converters generating pulse trains or group pulse trains consisting of unit pulses with an intermittent pulse intervention period.

14 is a waveform diagram illustrating various modes of group pulses applied according to the embodiments of FIGS. 11 to 13.

FIG. 15 is a circuit diagram illustrating the application of the embodiment of FIG. 11 to a spark electrodeposition process.

FIG. 16 is a waveform diagram of applied pulses in the embodiment of FIG.

FIG. 17 shows the application of the AC-DC-high frequency-DC converter of the present invention to an arc welding process.

FIG. 18 is a circuit diagram showing a portion of a circuit in the embodiment of FIG.

19 is a waveform diagram of pulses appearing in various parts of the circuit of FIG.

The present invention relates to a power supply for an electric machine, and more particularly to an electric circuit improved for such use.

The term "electroprocessing" means electro-discharge machining (EDM), electrochemical machining (ECM), etc. and spark electrodeposition (ESD), arc welding.

To date, machines designed to perform electromachining convert the size of the commercial alternating current (AC) to an appropriate level, after which the converted alternating current is rectified to DC, and then both ends of the processing gap formed between the workpiece and the processing electrode by a switching device. Inevitably, a large capacity transformer is needed to be able to be converted into an electric pulse train having a desired pulse duration, interval and frequency for application. As is well known, water or oil is used for EDM as the processing medium, or an electrolytic solution is used for electrodeposition processing.

In this case, high-density current processing, that is, high-density electrodeposition, is performed by applying electrical energy in a pulsed manner. However, since low frequency commercial alternating currents of 50 Hz to 60 Hz are used, the size and weight of the transformer, and thus the overall power supply, becomes unnecessarily large. Furthermore, this type of power supply requires the use of a reactor for control purposes. Such a reactor exhibits a relatively slow response speed, resulting in poor power supply efficiency.

In addition, the power supply of the type described above requires a large main power supply for supplying the processing energy to the processing gap, and one or more auxiliary power supplies having small but different capacities for controlling the machine and the mechanical components, and thus the size and weight of the power supply. Becomes large and becomes undesirable. That is, the power supplies described above are large in size, heavy in weight, and poor in efficiency.

Therefore, it is an object of the present invention to provide a power supply of a good electric machine, which is small in volume and weight, and has high efficiency and high stability.

According to the present invention, there is an improved power supply of an electric machine equipped with an AC-DC-HF-DC converter, and the AC-DC-high frequency-DC converter can obtain commercial AC. Rectifier for converting AC to DC, and Rectifier for converting AC to DC, and ON / OFF by generator or pulse generator to generate high frequency (HF) exchange or pulse train having higher frequency than commercial AC from DC output. An adjustable switching device, a transformer device for converting the amplitude of the high frequency to a desired level, and a second rectifying device for converting the converted high frequency output into a DC output of the adjusted amplitude. According to the present invention, the final direct current output is pulsed by a second switching device that can be turned on and off by a second oscillator so as to be applied as a pulse train across the processing gap formed between the workpiece and the electrode. The transformer device has a first winding connected to the first rectifying device and the first switching device, and a plurality of secondary windings, one of the secondary windings being rectified by the rectifying action of the second rectifying device. Used to cause an output to be generated, the remaining secondary windings constitute inputs for operating or controlling the parts of the power supply or the parts of the electric machine equipped with the power supply.

Hereinafter, the present invention will be described in more detail with reference to the drawings. Like numbers in the drawings indicate like parts.

In FIG. 1, the input terminal 1 is an input terminal of a commercial AC power supply, and the rectifier 2 full-wave rectifies AC to generate a DC output between both ends of the output terminals 2a and 2b. It is a rectifier. The switch 3 formed of a transistor is preferably at least 1 KHz, preferably at least 1 KHz, so that a high frequency current can be provided at both ends of the network formed by the primary winding 51 and the capacitor 6 of the transformer 5 connected in parallel with each other. The on / off control is performed by the oscillator 4 having an oscillation frequency of 10 to 50 KHz. The transformer 5 is provided with as many secondary windings 53, 54, 55, ... 5n as necessary, and these heavy windings 53 are configured to generate processing energy. The windings 54-5n constitute output windings for generating control or operating signals for various power supplies and mechanical components. The number of turns of each winding is adjusted to produce the desired voltage level of high frequency alternating current.

The output winding 53 constituting a part of the main power supply or the processing power supply device is coupled with the rectifier 73 disposed in front of the level stabilization network 83. The direct current signal from the network 83 is pulsed by a switch 93 formed of transistors on / off controllable by the oscillator or pulser 10.

In the following description, the operation of the power supply apparatus according to the present invention is mainly described for the electric discharge machining (EDM).

The oscillator 10 generates an adjustable switching signal to the switch 93 so that processing pulse trains of a predetermined pulse period and interval are applied across the processing gap GAP.

The high-frequency alternating current generated across the winding 54 is generated by rectification by the rectifier 74 and smoothed by the network 84. The switch 94 is a capacitor connected across the load terminals (-, +). It is controlled by an oscillator operating in the frequency range 20 to 40 KHz, that is, a pulse 11, in response to the voltage level of (12), so that a stable output (-, +) is obtained. When this network is used for electrochemical processing or electrodeposition, the switching frequency may be increased to produce a stable direct current voltage.

The other output winding 55-5n is provided with a rectifier when DC output is required, and a frequency converter is installed when AC output is required. If voltage level stabilization is not required, of course there is no need to install a voltage stabilizer switch. In general, switching control of transistors or devices of the same type is required, but not necessarily the operation of display circuits such as LEDs (light emitting diodes), LCDs (liquid crystal displays), and the like.

The AC-DC-high frequency-DC converter circuit according to the present invention has the following advantages. Some desired output voltage can be easily obtained from the zero level to the rated level of the transformer by adjusting the oscillator's impact factor to generate a high frequency signal. In addition, since the transformer is used with a higher frequency signal, the transformer can be made smaller, so that the power supply can be smaller in size and weight than the conventional device. In addition, a single transformer is used for multiple output or process energy and instrument control purposes, making the device more compact. The output from the processing energy winding 53 is stabilized by the on / off switching control of the switch 93, and a pulse is applied to the processing gap G across the processing gap G in a predetermined manner. As a result, the input terminal 1 Even if there is a variation in the voltage shown in Fig. 1), there is no effect on the machining operation in the gap G effectively isolated from the input terminal 1. Thus, a stable and balanced series of discharges are thereby performed, resulting in high accuracy and high efficiency. By virtue of the same stability characteristic, the output voltages generated at the other load terminals are actually independent of the fluctuations in the voltage at the input shaft 1.

3 shows a variant of the output voltage stabilizer, in which a switch 13, which is a transistor, is connected in parallel with an input network controlled by an oscillator 14 operatively responding to an input voltage. 4 shows another variant embodiment in which switch 13 is connected in series to an input network operated by oscillator 14. 5 is a variant embodiment showing that the transformer 5 is provided in the output network to generate a converted output. These modified embodiments can be used in the same manner as described above.

Referring to Figs. 5 and 6, the description and operation description of the AC-DC-high frequency-DC converter circuit according to the present invention will be further understood. In the circuit of FIG. 5, the HF transformer 5 is shown to include only a machining output, but additional output for control purposes may be provided, as described in connection with FIG. 1. As already explained, the high frequency voltage withdrawn from the secondary winding 53 of the transformer 5 is supplied to the rectifier 7, where it is converted into a direct current of equally regulated voltage amplitude. The rectified direct current is pulsed by three switches which selectively operate in the switching device 9. These three switches are configured as a "first" switch 9a, a "medium" switch 9b and a "finished" switch 9c, each of which is between the electrode E and the workpiece W. The pulses of variable parameters, i.e., the oscillator 10, are operated to generate a predetermined pulse period and interval or a pulse string of pulse periods and intervals varying within a predetermined range across the processing gap G. Resistors Ra, Rb, Rc are coupled in series with transistor switches 9a, 9b, 9c to set the pulse peak current in the individual networks (initial, intermediate, finish). Furthermore, in this embodiment, the sense resistor 16 is responsive to the gap voltage, current or impedance between the electrode E and the workpiece W, so that the arm 16a of the potentiometer connected to the resistor 16 is connected. By generating a signal proportional to the gap voltage or impedance magnitude in the control circuit 17, the operating mode of the oscillator 4 can be controlled according to the gap voltage, current or impedance.

As mentioned above, the pulser, i.e., the oscillator 4, operates to generate a control pulse of at least 1 KHz frequency so that the size and weight of the transformer 5 can be sufficiently small. The impact coefficient and frequency of these control pulses determine the HF output level with fast response speed.

The first switch 9a is operated by a pulser or oscillator 10 to provide pulse trains with a pulse duration between 100 μs and 10 ms. The finishing switch 9c operates to generate a pulse train having a pulse period of 1 to 5 s so that the switch 9b generates a pulse having a pulse range in the middle range. Pulse intervals for these pulses are typically set between 1 and 10 ms. The resistance values of the resistors Ra, Rb, Rc are in the initial processing in which the switch 9a is operated, in the finishing processing in which the pulse has peak peaks between tens of amps and 1 kiloamp and the switch 9c is operated. The pulse has a peak current of 1 to 10 amperes, and the pulse is set to have a peak current in the range in the intermediate processing in which the switch 9b is operated.

As long as the pulser 10 can be configured as an independent oscillator, the pulser 10 is designed to respond to a gap condition in the EDM or ECM processing gap G between the electrode E and the workpiece W. As a result, the period, interval and pulse repetition ratio of the pulses to be applied to the processing gap G will be changed so that the processing can be performed under an optimum state.

In addition, the gap state is detected by the resistor 16 responsive to the gap voltage to operate the control circuit 17 so that the control of the pulser 4 is performed, so that the switching control pulse transmitted to the switch 3 as a result. Their operating frequency and impact coefficient are modified to control the level of the output alternating current of the transformer 5. Since the control frequency is certainly higher than the frequency of the commercial AC input (i.e., 50 to 60 Hz), the control is performed at an extremely fast response speed. Therefore, when a short circuit condition occurs in the gap G, it is possible to continuously process by restoring the normal gap state in a momentary response so that any damage or arcing that may occur as a result is instantaneously prevented. It has high efficiency with stability.

As long as the HF-AC generated by the on / off operation of the switch 3 has a frequency not lower than 1 KHz, the energy efficiency is particularly remarkable when it is set at least twice the repetition rate of the processing pulses, especially for the initial processing. It is improved enough.

6 shows the relationship between the frequency of high-frequency alternating current and the pulse period of the processing pulse. In the initial processing, the processing pulses obtained by pulsed the direct current obtained by full-wave rectification by the rectifier 7 in the output winding 53 of the transformer 5 (by the switch 9a) are the sixth (a). As shown in the figure, it has a pulse period of 50 μs with 50% of the impact coefficient (or a pulse interval of 50 μs). In the case where the high-frequency alternating frequency has a frequency of 20 KHz (figure 6 (a)), the alternating voltage traverses the zero level once during the on-time Ton of the processing pulse shown by the dotted line. This means that the current limiting resistor (ie, the resistor Ra connected in series with the switch 9a) of the direct current processing pulse circuit can be set lower than the threshold value.

In the prior art in which a direct current for a working pulse is obtained by direct rectification of a low frequency (50 to 60 Hz) commercial alternating current, the pulsed processing current has a higher frequency than the input alternating current (for rectification), and as a result, an input alternating current The voltage (figure 6 (a)) does not cross the zero level during each processing pulse on-time Ton. This requires that most of the current control in the processing circuit is performed by the resistance Ra of the series connection with the processing pulsation switch 9a. That is, for example, a peak current of 200 amps, a current voltage of 100 volts, and a circuit resistance Ra of 0,5 ions are required. In contrast, in the present invention, only 0.1 to 0.05 ohm is sufficient for the resistance Ra.

In the "intermediate processing" in which the switch 9b operates to generate a pulse duration Ton, i.e., a processing pulse of 10 mu s (figure 6 (d)), the frequency of these pulses is higher than the power frequency of 20 KHz. Therefore, the AC voltage (Fig. 6 (a)) does not cross the zero level during each working pulse on time Ton. For example, in order to obtain a peak working current of 10 amps, it is necessary to set the resistance value of the series resistor Rb to 10 ohms. In addition, for finishing with an on time Ton (Fig. 6 (e)) of 2 mu s, the series resistor Rc must have a resistance value of 100 ohms so that a pulse peak current of 1 amp is obtained. Therefore, as long as significant resistance values are required within the intermediate and finish machining ranges, this requirement is not difficult to achieve because of the low power requirements in these processing areas.

In the initial processing where large peak currents must be applied, it is important that a significant reduction in circuit resistance (approximately 10) occurs, resulting in a significant improvement in power efficiency (10 times).

Of course the frequency of the high-frequency alternating is preferably changed. Therefore, the longer the pulse period Ton, the lower the high frequency, and conversely, the shorter the pulse period, the higher the frequency.

FIG. 7 shows another embodiment of a power supply having a high voltage generator A and a low voltage overhead power supply B configured as the described AC-DC-high frequency-DC converter, and FIG. The omitted filter 1a is provided on the output side of the input terminal 1. The output windings of the transformers 5 and 51 form a high voltage and a low voltage power supply, respectively. Switch 9 in the high voltage (HV) secondary network of the high voltage converter (A) and the low voltage (LV) secondary network of the low voltage converter (B), respectively, to pulse high voltage DC and low voltage DC, respectively. Is operated by a common pulse, i.e., oscillator 10, as opposed to the operation of the pulser or oscillator 4 for switches 3 and 31 in the primary DC networks. A processing pulse train of a predetermined pulse period and interval is provided between the workpieces W. FIG. However, it is possible to provide two pulses for the switches 9 and 91 so that the high voltage switch 9 is turned off at the start of gap breakdown or dustproofing.

This embodiment is provided with further controllers 18 and 181 responsive to a gap condition, in which the signals respond to the increased current amplitude when the gap G is shorted in response to the discharge current. The operation of the transducers 4 and 41, wherein the operation of the transducers A and B reduces the impact coefficient and / or the frequency of the pulsers 4 and 41 so that the machining gap G is easily restored to its normal state. It is designed to control the pulser (4, 41). The gap state may be represented by the magnitude or impedance of the high frequency component, the resistance, and the gap voltage.

The output parameters of the pulsator 10 are adjusted in accordance with the desired processing mode of initial, intermediate or finish and close processing as in the above-described embodiment. When the switches 9 and 91 are turned on for high voltage-DC and low voltage-DC pulses, respectively, a low voltage processing pulse in which a high voltage interval trigger pulse is superimposed is applied across the processing gap G in each processing pulse period. . The superposition of the high voltage pulses on the low voltage processed pulses facilitates the interval break so that the open pulse voltage pulses are minimized. The pulser 10 is deformed to operate the switch 9 at a higher frequency than the switch 91 so that several high voltage pulses appear superimposed on a single low voltage processing pulp.

In the modified embodiment of FIG. 8, the secondary winding of the high voltage transformer 5 is provided with a half-wave rectifier 7d such that the high voltage-high frequency pulsating current is superimposed on the low voltage working pulse train from the processing power supply B. Oscillator 41 in low voltage converter B operates at a frequency of 50 to 100 KHz, while oscillator 4 in high voltage converter A operates at a frequency of 100 to 500 KHz.

For example for an oscillator 4 operating at a frequency of 50 KHz, high voltage output pulses with a pulse duration and interval of 1 μs will be applied directly across the processing gap G. As in the above-described embodiment, the low voltage processing pulses have a predetermined pulse duration Ton and interval Toff (e.g., 1 to 5 microseconds in the finishing process and 100 microseconds to 10 ms left in the initial processing). The output current is obtained by pulsed by the switch 91. A signal is transmitted from the oscillator 10 to the oscillator 4 in order to synchronize the low voltage pulses and the high voltage pulses, respectively. The high voltage pulses are set to have a voltage of 200 to 300 volts, and the low voltage pulses are set to have a voltage of 20 to 30 volts. The discharge trigger efficiency is increased by repeatedly superimposing the low voltage high voltage pulse having a pulse duration of 1 μs on the low voltage processing pulse having the pulse duration according to the desired processing mode, and the power interruption is facilitated when a gap short circuit condition occurs. . In the embodiment of FIG. 8, the control devices 18, 181 respectively respond to the direct current in the primary circuit network of the high voltage transformer 5 and the low voltage transformer 51, and the blocking diode 19 is the secondary circuit of the low voltage transformer 51. It is provided in the network.

In the modified embodiment of FIG. 9, the direct current output of the high voltage converter A is continuously applied across the processing gap G without being pulsed, while the direct current output of the low voltage converter B is switched 91. It is pulsed by and superimposed on the continuous high voltage DC and applied to both ends of the gap G. As a result, the processing cycle of the gap breakage by the high voltage-DC prior to the low voltage pulse current pulse is repeatedly performed. In this embodiment, the clock oscillator 20 is similar to the switch 91 in the secondary network of the low voltage converter B, which is the initial setting to be applied to the switches 3 and 31 in each primary network of the converters A and B. The control pulse of the parameter is used to provide a clock pulse of 1 MHz frequency which is processed by the counter 22 which provides the switching pulse.

FIG. 10 is selectively driven by a switch 23 to be operated in combination with the high voltage converter A so that the desired initial, intermediate or finished machining of the circuit arrangement is achieved, and a plurality of connected in parallel Low voltage converters B ₁ , B ₂ , B ₃ . Therefore, in the first machining, all transducers B ₁ , B ₂ , B ₃ are operated with the maximum two transducers B ₁ , B ₂ in the machining gap G, and in the finishing machining only the transducer B _1. ) Is driven.

The modified AC-DC-high frequency-DC converter circuit shown in FIG. 11 is designed to generate pulse groups spaced apart from each other by a period Toff, each pulse group having a pulse period of 1 μs and a pulse interval of 1 μs. It includes a plurality of unit pulses. The use of a pulse group consisting of unit pulses gives the advantage of better surface finish, increased removal rate and reduced counter electrode wear due to increased processing stability. However, because of their individual size, extremely high response speeds are needed to control the unit pulses.

For example, in initial processing, although the energy of the individual unit pulses themselves is increased, the processing energy must be mass produced with a high current density with the unit pulse groups. In order to generate pulse groups, the conventional system has relied on switching the direct current obtained by the commutation of the commercial alternating current, but such a system did not sufficiently satisfy the above requirement.

In the circuit arrangement of FIG. 11 embodying the principles of the present invention, a switch of a transistor provided at the output of the rectifier 2 with respect to a commercial high flow obtained at the input terminal 1 and supplied through the filter 1a as in the above-described embodiment. (3) is controlled by the pulser 24 which defines the duration Ton and the interval Toff of the unit pulses. The pulser 24 has an input terminal 24a connected to an AND gate 25 having an input terminal 25a connected to the pulser 26 for determining the period Ton and the interval Toff of the pulse groups.

Therefore, the switch 3 has a width (Ton and Toff) of at least 1 μs determined by the pulser 24 during the time Ton of 10 ms within the normal 10 μs when the pulser 26 generates a “1” pulse output. It is turned on and controlled to pulse the direct current output of the rectifier 2 so that a continuous group of unit pulses is generated. The switch 3 turns off and maintains its state when the pulser 26 generates a " 0 " pulse output or no pulse output and during the non-occurring period so that the idle time Toff results. It is inserted between these successive unit pulse groups. A typical mode of this group of continuous pulses is shown in FIG. The number of unit pulses included in each group of consecutive pulse groups is determined in accordance with the desired particular processing mode, i.e., the first, intermediate and finishing modes. The duration Ton and the interval Toff of the unit pulses were determined as follows according to the desired processing mode. In other words, in the finishing, Ton = 1μs, Toff = 10μs to 20μs, in the intermediate machining Ton = 5μs, Toff = 15πs to 20μs, and in the initial processing, Ton = 50μs to 100μs, Toff = 20μs to 50μs.

The secondary input terminal 25b provided for the gate 25 is connected to the detection circuit device 27 which responds to the dustproof state in the processing gap G. This circuit arrangement is responsive to the gap voltage to perform voltage-frequency conversion such that a signal pulse of frequency proportional to the voltage detected in the processing gap G is generated. The signal pulses are synthesized at the AND gate 25 with the output pulses from the pulser 26, and the synthesized signal is applied to the pulser 24 so that the pulses are deformed during the period Ton and interval Toff. It generates continuous unit pulse groups with.

The switching operation by the switch 3 together with the oscillation capacitor 6 generates a high frequency alternating pulse of about 500 KHz converted by the transformer 5. The transformer 5 in this embodiment has a first secondary winding 53a that produces a relatively low voltage level, i.e. 35 volts, and a second secondary winding 52b that produces a relatively high voltage level, i.e. 200 volts. Have These two voltage outputs are applied across the processing gap G as high voltage pulses which trigger the electrical discharge of the gap by rectification by the half-wave rectifiers 7a and 7b respectively and low voltage pulses which maintain the triggered processing discharge. The dual output converters of this embodiment stabilize operation and increase power efficiency. Moreover, the size of the transformer 5 can be made smaller, thereby further miniaturization can be achieved.

In the case of the pulser 24 which responds to the output of the pulser 26 and the output of the detection circuit 27, various pulse control patterns shown in FIGS. 14 (b) to 14 (d) are obtained. FIG. 14 (b) shows the continuous unit pulse groups, where Too and Toff are deformed according to the gap state, so that the number increases and the width Ton becomes longer when the gap G is in a stable state. The group of pulses with reduced Toff) is applied, and the group of pulses with increased Toff is applied when Ton is reduced when the discharge state is bad. In the pulse control pattern shown in FIG. 14 (c), the pulse periods and intervals of the unit pulses are controlled in response to the discharge state of the processing interval, and in the pattern of FIG. 14 (d), the unit pulse and the parameters of the pulse groups are simultaneously Controlled is shown.

In the variant shown in FIG. 12, the pulser 24 defining the period Ton and the interval Toff of the unit pulses, and the pulsers 26 defining the period Ton and the interval Toff are ANDed. Is connected to the gate 28. The output of the AND gate 28 is applied to the switch such that a continuous group of unit pulses (as shown in Fig. 14 (a)) is provided to the processing gap G. In this variant, the pulser 24 is connected in response to the control circuit 29 generating a comparison signal between the processing gap voltage and the reference voltage such that the period Ton and the interval Toff of the unit pulses are deformed. .

At the same time, as in the above-described embodiment, the pulser 26 responds to the control circuit 27 such that the period Ton and the interval Toff are deformed, so that the control pattern shown in FIG. 14 (d) is obtained. To lose. When the connection circuit between the control circuit and the pulser 26 is omitted, the control state shown in Fig. 14 (c) is obtained.

In another variant of FIG. 13, the rectifier 2 has three direct current output networks with switches 3a, 3b and 3c respectively. Transformer 5a associated with switch 3a generates a high voltage of 200 to 400 volts in its secondary winding, while transformers 5b and 5c associated with switches 3b and 3c respectively have a low voltage of 30 to 50 volts. Each transformer output is rectified by the half-wave rectifiers 70a, 70b, and 70c to generate successive pulse groups that overlap the other pulse groups across the processing gap G. The switch 3a is controlled by the pulser 33 which defines the period Ton and the interval Toff of the unit pulses, while the switches 3b and 3c are connected to the period Ton of the successive pulses. It is controlled by a pulser 34 which defines an interval Toff. In addition, the pulser 33 is controlled by the pulser 34 so that unit pulses are generated only during the period Ton.

Continuous pulses generated by the control of the switches 3b and 3c are applied between the electrode E and the workpiece W during voltage reduction by the transformers 5b and 5c. By using multiple outputs, the increased processing energy is supplied to the processing gap G in a small separate transformer. Of course, when more processing current is required, the number of parallel networks is increased. The high frequency unit pulses generated by the control of the switch 3a raise the voltage level by the transformer 5a to the extent that it can reliably trigger the electric discharge in the processing gap G, and the continuous low voltage Superimposed on normal processing pulses. Thus, during each Ton of individual consecutive low voltage pulses, a high voltage unit pulse group having a period Ton and an interval Toff is applied.

Since high voltage unit pulses are used at the start of discharge, sometimes arcing or short circuits are easily solved by stopping control of the high voltage device so that a rapid recovery to an abnormal and stabilized processing state is usually performed. When one of the pulsers 33 and 34 responds to the information network 35 of the processing gap, the period Ton and the interval Toff of the unit pulses, and the efficient processing are automatically controlled to be performed. .

Fig. 15 shows the application of the AC-DC-high frequency-DC converter to the spark electrodeposition process according to the present invention. In such a system, the principle described in the preceding embodiments basically uses the processing gap G formed by the electrodeposited electrode E and the parallel workpiece W. According to a typical embodiment, the electrode electrode E vibrates with respect to the workpiece W by the electromechanical oscillator 36.

Up to now, the power supply device for spark electrodeposition in which the vibrating electrode is corroded by the energy of electric discharge and electrodeposited on the surface of the workpiece is used for charging and discharging of the capacitor connected to both electrodes and the workpiece. Such a system is characterized in that the electrodeposition rate and the possibility of removing the corrosion layer once electrodeposited onto the workpiece are limited.

The AC-DC-high frequency-DC converter according to the present invention is used to overcome the above-mentioned problems, in particular by controlling the pulses applied at both ends of the electrodeposition processing gap so that the continuous separated from each other by a moderately controlled rest period. When mass production with pulse group. It is used to solve the above problem.

As in the circuit arrangement described above, the rectifier 2 provides a direct current output pulsed by the switch 3. The switching control signal is coupled to an oscillator that generates control unit pulses, i.e., a pulser 38, and thus has an AND having a first input terminal 37a and a second input terminal 37b connected to the second AND gate 39. It is supplied to the gate 37. The AND gate 39 is connected to a second oscillator or pulser 43 that generates a control signal that intermittently or periodically intercepts unit pulses. The gate 39 is also connected to the processing gap detector 44 connected between the electrode electrode E and the workpiece W. FIG.

In the spark electrodeposition process, after the peak portion of the electrode E heated by electric discharge is electrodeposited on the surface of the workpiece W, the electrode E is separated to allow the corroded material to cool. When heating and cooling by electrical discharge and separation of an internal electrode are repeated, electrodeposition is performed. The vibration of the electrodes is usually done at a frequency of commercial alternating current to allow periodic contact and separation, while the processing pulses occur at a frequency of at least 1 KHz, resulting in a large number of electrical discharges during each oscillation cycle. As a result, the electric rate is increased compared to conventional circuits, that is, capacitor charge and discharge systems in which electrode vibration and pulse and generation are mutually synchronized.

The on / off operation of the switch 3 in response to the control signals from the pulser 38 and the pulser 43 is the period Ton shown in FIG. 16 respectively across the tank gap G. And continuous pulse groups having a predetermined number of unit pulses having an interval Toff, separated by a rest period Toff, and having this period Ton. Typically, Ton and Toffs are selected from 10 to 200 μs and Ton and Toffs are selected from 500 μs to 10 ms.

The paused electrode Toff is inserted in the middle to effectively cool the heated electrode E so that continuous discharge can be performed. As long as the electrode E is in contact with the workpiece W, a plurality of rest periods are used. By doing so, the chariot ratio is increased and at the same time the chariot surface layer is improved qualitatively.

The gap G detector 44, which responds to the electrical state between the electrode E and the workpiece W, is "0" so that the AND gate 39 does not drive when the gap G becomes excessively wide. Generate a signal. Therefore, the control signals from the pulser 43 cannot reach the gate 37 through the gate 39, so that the switch 3 remains off and the output pulses are applied to the machining gap G. It doesn't work. Since the interruption control of the chariot pulses has responsiveness at high frequencies of the processing pulses, a stable electrodeposition process can be performed along with easy processing pulse control in synchronization with the contact / separation vibration of the electrode.

The AC-DC-high frequency-DC converter according to the present invention is effectively applied to arc welding treatment.

In FIG. 17, the arc welding system is provided by a holder H having a pair of output terminals 45 of the welding power supply according to the present invention, which is shown connected to both ends of the electrode E and the workpiece W. FIG. A workpiece W ₁ and W ₂ welded with molten material from a supported electrode electrode E. The power pulsation switch 3 provided as in the embodiment described above on the direct current side of the rectifier 2 for commercial alternating current obtained at the input terminal 1 is provided with a high frequency pulser 46 and a low frequency pulser 47. Controlled by operation, consequently, successive unit pulse groups occur at the output terminal 45 of the system. Pulse grouping or periodic interruption of these unit pulses is done in the control switch 3a.

The high frequency pulser 46 is used to generate a control pulse having a ton interval Toff of a 10 KHz frequency and a waveform as shown in FIG. 19 (a), and the low frequency pulser 47 As shown in FIG. 19 (b), a control pulse having a period Ton, a pause period Toff, and a waveform is generated. As a result, it can be seen that the pulses from the switch 3a have a waveform as shown in FIG. 19 (c). In addition, it can be seen that the pulses generated at both ends of the electrode E and the workpieces W ₁ and W ₂ are waveforms as shown in FIG. 19 (d). The output voltage V of these pulses is adjusted high enough to trigger arcing, and the arc current Ip is adjusted to have a current density sufficient to maintain stable pulse arcing.

In FIG. 18, the input terminals 1 ', 1' ', the rectifiers 2', 2 '', the switching elements 3 ', 3' ', 3' '' and the input terminals 1 are shown. The output terminals 45 'and 45' 'corresponding to the rectifier 2, the switch 3 and the output terminals 45 of FIG. 17 are shown. The clock generator or pulse generator 48 corresponds to the high frequency pulse generator 46 of FIG. Other circuit elements within the circuit of FIG. 18, which is a detail of FIG. 17, include AND gates 54, 55, 56, 57, and preset counters 61, 62, 63, 64 that determine Toff, Ton, Toff, Ton. And RS bistable elements 65 and 66, divider 67, high frequency transformers 5 'and 5, half wave rectifier 7 and switching device 68.

In operation, when the monostable element 65 is set, the high frequency pulses from the generator 148 pass through the AND gate 55 and are counted by the counter 62. When the count reaches a predetermined value, the counter 62 generates an output pulse for resetting the element 65. This causes the high frequency pulses from the pulser 48 to pass through the gate 54 again and the counter 61 counts. Then, when the counting level of the counter 61 reaches the preset value, the RS bistable element 65 is returned to the set state. By repetition of this period, output signal pulses as shown in FIG. 19 flow out from the bistable element 65.

Similarly, bistable element 66 also provides output signals. However, since the divider 67 is located in the pressure channel, the latter signals have a frequency much lower than the frequency of the output pulses from the RS bistable element 65.

The impact coefficients and frequencies of the output pulses of the RS bistable elements 65 and 66 are easily preset, the frequency of the clock pulse 48, the frequency division of the divider 67 and the counters 61, 62, 63 and the like. This is done by adjusting the preset levels in 64).

The outputs of the RS bistable elements 65 and 66 have an output waveform applied to the AND gate 69 as shown in FIG. 19 (c). When the converter 68 is connected to the output terminal of the rectifier 7, a pulsed welding current as shown in FIG. 19 (d) is generated at the terminal 45 ', so that the electrode E and the workpiece to be processed. It is applied between the sieves W ₁ and W ₂ . Also, when the diverter 68 is connected to another output terminal, the high frequency alternating pulses are generated in successive pulse groups of 1 KHz frequency, each having a period Ton, and the output of the bistable element 65 is the transformer 5 '. It is used to control the switching element (3 '') in the primary axis of the bistable element 66, the output of the 19th (d) across the welding electrode (E) and the workpiece (W ₁ , W ₂ ) It is used to control the switching element 3 '' in the secondary axis of the transformer 5 'such that a waveform pulsed welding current as shown in the figure is supplied from the terminal 45''.

According to the present invention as described above, there is provided an improved power supply device of an electric machine, which is compact and economical, and exhibits an efficient processing operation without any problems.

Claims (1)

An input device that can be connected to a low-frequency commercial AC source without a transformer; A rectifier connected directly to the commercial exchange source and converting a commercial exchange into a direct current; A pulseizing device which is directly connected to the rectifier and generates an output of a higher frequency than the commercial alternating frequency by pulsing the direct current; A high frequency transformer connected to the pulse device to convert the output of the high frequency into a desired level; An electrical device comprising a device connected to the transformer to generate a non-linear series of empty pulses of a predetermined pulse parameter from the high frequency output of the desired level and to be applied to both ends of the processing gap between the hollow electrode and the workpiece. Power supply of the machine.

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