SU1393557A1 - Apparatus for electric discharge alloying - Google Patents

Description

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The invention relates to electrophysical processing methods, in particular, to installations for electrically sparking alloying of machine parts and metalworking tools in order to strengthen them and restore dimensions.

The purpose of the invention is to improve the quality of doping by eliminating switching elements from the discharge circuit and ensuring the oscillatory discharge of the capacitor, as well as by eliminating short circuits. I.

The drawing shows a schematic diagram of the device.

The device contains a power source of 1 direct current and low voltage.

ny source of direct current 2. A switch 3 on a composite transistor is connected to a DC power source 1, in the collector circuits of which a storage capacitor 5 is connected via limiting resistor A with output terminals 6 and 7 for connecting the vibrating electrode 8 and the treated part 9 and a 10-second transistor switch common emitter, the output of which is connected with the input of the transistor switch 3 on the composite transistor. A threshold device 11 and a transistor generator 12 of pulses, loaded onto the coil 13 of an electromagnetic vibrator, are connected to a low-voltage source 2 of direct current. The threshold device; 11 is designed as a two-stage direct current amplifier with silicon Zener diodes at the input and as an interstage connection. The output of the threshold device 11 is connected to the input of the saturated transistor switch 10 with a common emitter. In this case, the two like poles of the power source 1 of direct current, low-voltage source 2 of direct current and output terminal 7 of storage capacitor 5 are connected together, and the second pole of low-voltage source 2 of direct current is connected to the second output terminal 6 of accumulative a capacitor 5 connected to the key 3 on the compound transistor. Parallel to the resistor 14 is connected to the peak detector 16, the output of which is connected to the input of the threshold device

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11. An ammeter 17 is connected to the collector circuits of the key 3 on the composite transistor to measure the average value of the doping current. Both DC sources 1 and 2 are powered from one transformer (not shown) and each contains a single-phase bridge rectifier with a filter at the output in the form of a capacitor, the transformer winding, to which Kjnci4eH DC power source 1, is made with taps for staggered voltage regulation. The transistor generator 12 pulses is designed to generate rectangular voltage pulses applied to an electromagnetic vibrator coil 13 and a variable resistor in series with a vibration amplitude regulator.

The device works as follows.

When the device for electric-spark doping is switched on in the network, the first stage of the threshold device 11 is in the cutoff state, and the second stage is due to the base current through the inter-stage silicon Zener diode. The saturated transistor switch 10 with the common emitter is also expansive and, in turn, maintains the key 3 in the saturated state on the composite transistor. The storage capacitor 5 is charged from the DC power source 1 through the limiting resistor 4, ammeter 17 and Kjnci4 3 on the composite transistor. When approaching due to the flow of a current pulse through the coil 13 of the electromagnetic vibrator of the vibrating electrode 8 and the workpiece 9, an oscillating damping discharge of the storage capacitor 5 occurs and its discharge current is processed by doping. From the moment the spark p) breakdown occurs, the discharge current of the storage capacitor 5, which has the form of a damped sinusoid, and the pulse current from the low-voltage direct current source 2 through the resistor 14 and diode 15 flow through it. greater than the magnitude of the pulse current through the resistor 14 and the diode 15, then a voltage pulse modulated by the discharge current of the storage capacitor 5 is discharged at the resistor 14, a radio pulse. The peak detector 16 converts a radio pulse into a voltage that repeats the shape of the envelope of the radio pulse that enters the threshold device 11.

In this case, the first cascade of the DC amplifier of the threshold device 11 enters the Nascene mode, and the second cascade of the DC amplifier, the saturated transistor switch 10 with a common emitter, and the switch 3 on the composite transistor switch to cut-off mode. After the moment when the vibrating electrode 8 is detached from the workpiece 9, the electrical properties of the spark gap and the charge of the storage capacitor 5 are restored through a diode 15 and a parallel connected resistor 14 and peak detector 16 from the low-voltage DC source 2 to the value determined by the threshold triggering the threshold device 11. Thereafter, the threshold device 11, the saturated transistor switch 10 with the common emitter and the key 3 on the composite transistor are reset to the initial state, and further a series of storage capacitor 5 occurs through a limiting resistor 4, an ammeter 17, and a switch 3 on the composite transistor from the DC power source 1. In the future, the work cycle is repeated.

Thus, the power source 1 of direct current is completely different by the time of breakdown of the spark gap, the contact of the vibrating electrode 8 and the workpiece 9, and until the storage capacitor 5 is charged from the low-voltage source of the direct current source 2 to the value determined by the threshold of threshold device 11. This prevents the formation of arc discharge and the occurrence of burns.

The voltage of the low-voltage direct current source 2 applied to the spark gap through diode 15 and in parallel with the connected resistor 14 and peak detector 16 is chosen taking into account that due to the energy of this source between the vibrating electrode 8 and the workpiece 9 there can be no spark and arc discharge. Since in this device the storage capacitor 5 is directly connected to the spark gap, the pulse duration of the discharge capacitor capacitor 5 through the spark gap is determined by the capacitance of this capacitor, the active resistance of the discharge channel, the resistance and the inductance of the connecting wires to the storage capacitor 5 and the spark gap, and the well-known condition for obtaining the oscillatory discharge cone is easily realized. capacitor through inductance and resistance:

R / 2

where R is the active resistance of the cana; la discharge and connective

wires; L - inductance of the connecting

wires; С - capacitor capacitance.

Tests of the testable apparatus for electric-spark doping have shown that it allows to obtain current pulses through the spark gap, which have the form of a damped sinusoid, while completely eliminating short-circuit currents and eliminating the occurrence of burns on the surface to be treated. Due to this, the quality of the surface to be treated is improved by 1-2 classes.

Claims (1)

DEVICE FOR ELECTROEROSION ALLOYING, containing a direct current source connected via a transistor key to a storage capacitor, characterized in that, in order to improve the quality of alloying, an additional low-voltage direct current source connected to the storage capacitor through a diode and resistor, a peak detector, is introduced connected in parallel to the resistor, and a threshold element connected between the output of the peak detector and the base of the transistor switch. Q0 ς © co SL SL) 393557