SU917993A1 - Apparatus for electric spark alloying - Google Patents

Description

(S) DEVICE FOR ELECTRICAL SPREADING

I

 The invention relates to devices for electrophysical processing methods, in particular, to electric-spark installations for doping and strengthening of machine parts and metal-working mystrumite.

A device for electric spark doping is known, which consists of a voltage transformer, a rectifier, a storage capacitor, thyristors, diodes, an electromagnetic vibrator with a switching coil connected to an alternating current circuit, a reinforcing electrode and a contact plate l.

The operation of the electrospark doping device consists in the accumulation of electrical energy on the capacitor plates and its subsequent release by pulsed discharge between the surface to be hardened and the electrode. The switching circuit of the discharge circuit is carried out by a vibrating electrode.

The disadvantage of this device is that the electrode can stick to the surface being treated. This leads to the appearance of short-circuit currents on the interelectrode gap, the magnitude of which is 2-3 times higher than the operating currents. The resulting excess energy is quenched in a transformer with a high inductance of dissipation, which leads to an increase in power consumption, overheating of the device and a decrease in its reliability. In order to cool the electrode, it is necessary to take short breaks, which reduces labor productivity.

In addition, the occurrence of short-circuit currents leads to the appearance of burns on the alloyed surface.

The purpose of the invention is to increase the efficiency, device performance, as well as improve the quality of surface doping. This goal is achieved by adding an additional thyristor, a transformer, to a device containing a voltage transformer, a rectifier, a digging capacitor, thyristors, diodes, an electromagnetic electromagnetic vibrator with a switching coil connected to the AC circuit, a reinforcing electrode and a contact plate. current, a stabilizing capacitor and an additional coil in the vibrator, the current transformer being connected to the common power supply circuit of the device, the control electrode of the additional thyristor is connected to the transformer the current torus, and the negative pole of the thyristor through a stabilizing capacitor is connected to an additional coil, which is placed on the same core as the switching coil. The drawing shows a schematic of a device for electric-spark doping. The device contains a voltage transformer 1, designed for galvanic isolation between the network and the vibrator electrode 2. A switching coil 3 of the vibrator and a rectifier per diode are connected to the secondary winding of the transformer; x -7. A rectifier through a limiting diode 8 and an ammeter 9 is connected to a storage capacitor 10, in parallel to which. I connected the discharge resistor 1, which listened to reduce the voltage on the capacitor 1 (1 to a safe value when operating in idle mode. Parallel to the capacitor 10 are connected the electrode 2 of the vibrator and the contact plate 12, on which I install the workpiece. For measuring the amplitude value the output voltage of the capacitor 10 is parallel to it, together with the diode 13 and the capacitor k, a voltmeter 15 is connected. To the output of the rectifier are connected a resistor 16 and a thyristor 17 which is controlled by a key of the capacitor 10. In the common circuit The device is powered by a current transformer 18, which in. the time of occurrence of a short circuit on the interelectrode gap 2-12, senses a voltage pulse and transmits a current pulse to the additional thyristor 19 connected in parallel with the capacitor 10 connected in parallel with a current transformer, and a negative pole through a stabilizing capacitor 20, which serves to force the operation modes of the thyristor 19, which contributes to closing it and preparing for the next cycle, according to The key to the additional coil 21 placed on the same core as that of commuting coil 3, wherein the second terminal of the coil 21 is included in the total circuit power device. The current pulse through the stabilizing capacitor 20 is supplied to the vibrator coil 21, which increases the magnetic flux strength, which separates the strengthening electrode 2 from the workpiece 12 and opens the circuit, interrupting at the very beginning the possibility of a short circuit. 9 idle mode, the device operates as follows. From the secondary winding of the voltage transformer 1, the current goes to the switching coil 3 of the vibrator and the rectifier over diodes -7, the limiting diode 8, the ammeter 9, the storage capacitor 10 and again to the rectifier. The capacitor 10 is charged, and when it is charged to a value equal to the voltage specified by the resistor 16, the thyristor 17 is opened, and the current flows through the open thyristor to the rectifier. The charge on the capacitor 10 stops, and in 1-2 seconds. it is discharged to resistor 11 to a safe value of 0.5-1.0 volts. The operation mode is initiated by touching the reinforcement electrode 2 to the workpiece, i.e. the closure of contacts 2 and 12, which occurs at the moment of transition of the supply voltage through zero, since The vibrator wheel 3 of the vibrator is connected to the secondary winding of the t1e voltage transformer t. During the half period, the following processes occur. When the contacts 2 and 12 are closed, the capacitor 10 is discharged and the thyristor 17 is turned off. When contacts 2 and 12 open, capacitor 10 is charged along the circuit: rectifier, diode 8, ammeter 9, capacitor 10 and rectifier to a level that is set by an adjustable resistor 16. When the contacts 2 and 12 re-closes, the capacitor 10 is discharged, and thyristor 17 is turned off.

When a short circuit current occurs in the interelectrode gap 2-12, a voltage pulse appears on the secondary winding of the current transformer 18, which opens an additional thyristor 19, and a current pulse through the stabilizing capacitor 20 is supplied to the additional vibrator coil 21.

This increases the magnetic flux force, which opens the strengthening electrode 2 from the product 12, and opens the circuit, interrupting at the very beginning the possibility of a short circuit on the Stabilizing capacitor 20 forces this mode, helps close the additional thyristor T9 and prepare it for the next cycle.

The use of the proposed device eliminates the possibility of occurrence of short-circuit currents at the very beginning of the process, due to which the efficiency of the device increases by 10-15, the labor productivity rises by 25-30%, as in rough modes

there is no need for short doping intervals every 20-30 seconds. Reducing heating improves device reliability. Elimination of short circuits eliminates the possibility of burns on the hardened surface, thereby improving the quality of doping. In addition, eliminating the possibility of transition of a spark discharge into an arc allows the use of a simpler voltage transformer, smaller in voltage. dimensions and weight.

Claims (1)

Invention Formula An electrospark doping device containing a voltage transformer, a rectifier, a thyristor, a storage capacitor, and an electromagnetic vibrator connected to an alternating current circuit and associated with a hardening electrode, in order to increase the efficiency of the device, as well as improve the quality doping, it is equipped with an additional thyristor connected in parallel with the storage capacitor, a current transformer, the primary i winding of which is connected to the common power supply circuit of the device , a stabilizing capacitor and an additional coil in the vibrator, with the control electrode of the additional thyristor connected to the secondary winding of the current transformer, and the cathode is connected to the additional coil in the vibrator via a stabilizing capacitor. Sources of information taken into account in the examination 1o USSR Author's Certificate Vf 395207, cl. B 23 P 1/02, 1371. R "M N 0 "S l Xi 4h CZDfc: J5 five 6h