SU121016A1 - Device for feeding an electrode tool in EDM machines for piercing deep holes - Google Patents

Description

The invention relates to devices for supplying an electrode-tool in EDM machines for piercing deep holes, consisting of an electrode-carrying slide tool with a nut, a lead screw, a differential and two motors. The slider is moved using a spindle driven by a differential, one of the gears of which rotates through a gearbox with a direct current motor of a follower system, receiving a signal from the working circuit, and the second (also through a gearbox) with an unregulated asynchronous AC motor.

In the known devices of this kind, the removal of the tool electrode is relatively slow, since the unregulated engine is turned on permanently and in the differential speeds of the engines are subtracted.

The present invention allows accelerating the elimination of short circuits by accelerating the removal of the electrode tool and returning it to its original position.

This is achieved by connecting an unregulated motor to a power source through an intermediate relay, which is energized via a voltage gate, removed from the core of the regulated motor. Owing to this, the unregulated motor is turned on only when the tool is retracted or returned with the direction of rotation, in which the speeds of the motors in the differential add up, but when the electrodes are moved mechanically at high speed, there is a danger of a breakdown when in contact with the part. Wear-resistant graphite electrodes are especially prone to breakage. There is a need to create a device to protect the electrodes from possible damage.

Therefore, according to the invention, in order to turn off the unregulated electric motor, the accelerated supply is shortly before the electrodes come into contact, and a memory device is used, made in the form of a pipe sitting on a slider (passed through a bracket vertically along a sliding nozzle).

No. 121016

a braking spring brake, and a spring-loaded stem passing through the tube, abutting against the body of the product and bearing on the upper Koinie coupling, disconnecting the contacts of the end switch of the fast feed motor down.

FIG. 1 shows the kinematic diagram of the machine; in fig. 2 is a diagram of a storage device; in fig. 3 is an electrical circuit of a memory device.

From the automatically controlled motor of the tracking system / (Fig. 1), through the gearbox 2 and one of the wheels of the differential 3, the rotation is transmitted to the drive screw 4. The latter drives the slide 5 through the uterine nut 6 and feeds the tool electrode 7 towards the workpiece 8, immersed in the bath 9.

To accommodate accelerated idle strokes, an asynchronous electric motor W was applied, which, through the gearbox U / and the second wheel of the differential 3, drives the lead screw 4 and the slider 5. If the machine worked for some time and the electrode 7 managed to penetrate into the workpiece 8, then with a short circuit 1П1и the fast moving mechanism will carry out an electrode withdrawal / indefinite, depending on random circumstances.

After the short circuit is eliminated, it is necessary to bring the electrodes together again. The approach of the electrodes on a slow run (from an automatically controlled engine) is too long to produce too, but it is dangerous to bring them together at an accelerated speed, since an electrode may break /.

According to the invention, a device is used which "remembers what position the slider 5 was in at the moment of short circuit and returns it to its original position {fig. 2). To guarantee against possible damage, the slider 5 should be stopped a little earlier than it will reach its initial position.

A slider 5 is attached to the slider 5 carrying the electrode tool 7. It has a tube 13 with a rod 14 on a sliding fit. The latter plays the role of a probe: as the electrode is inserted into part 8, the rod 14 raises the pipe 13 through the spring 15 13, the spring 15 is compressed and the ring 16 attached to the rod 14 depresses the button of the limit switch GC. The contacts of which are closed in the normal position.

As soon as the electrodes are short-circuited and the mechanism for quickly removing the electrode comes into operation, the electromagnet EV turns off, releases the measles 17, and the rod 18 under the action of the spring 19 will fix the position of the pipe 13 at the moment of the start of the short circuit.

As the slider 5 rises, the rod 14 will be lowered by the action of the spring 15 until the ring 16 rests on the end of the pipe 13. At the same time, the limit switch of the SCRE opens.

When the short circuit of the electrodes is eliminated, the movement of the slide 5 will begin. At the same time, the rod 14 first upsts the part 8 and begins to slide into the pipe 13, deforming the spring 15. After a given path has depleted (which is adjusted by fitting the ring 16, the ring 16 bends the ZKV button of the switch with its bevel and it closes. This serves as a signal for Turn off the accelerated feed.

By inertia, the slider 5 will pass a little further down, but no damage will occur, since the end pin of the SCW will be triggered in advance, due to the movement of the rod 14 under the action of the spring. The 1KB and 2KB end points serve to limit the progress of the slide up and down.

The electrical circuit of the device is shown in FIG. 3. To the measles of the adjustable electric motor 1 through the gate CB is connected the relay IP. It is included so that it works only when

short-circuiting the electrodes (when the polarity on the core is 1monted and the current begins to flow through the valve).

The IP relay is taken with the required time delay (2-5 seconds). When the relay IP is activated, the 1K contactor is turned on, which starts the induction of the asynchronous unregulated motor 10. The accelerated removal of the electrode begins.

At the same time, the braking electromagnet EV activates, fixing the position of the pipe 13 (Fig. 2).

When the short circuit is eliminated, the IP relay returns to its original position and turns on the IK and 2K contactors, and then switches the motor 10 to reverse (moving the electrode). As soon as the end of the SCA contactor 2 is tripped, the contactor 2 will be disconnected and the accelerated feed will stop. At the same time, the brake magnet EV is switched off. The buttons 1KU and 2K.U serve for manual starting of the electric motor 10 forward and backward. The 1KB and 2K limit switches limit the accelerated movement of the slide carrying the electrode tool.

Subject invention

Claims (2)

1. Device for feeding the electrode-tool in EDM machines for the forgiveness of 1 deep holes, consisting of a slider carrying an electrode tool with a nut, moved by a lead screw, driven by a differential, one of which is rotated (Th;) without the reducer is a direct-current motor of the follow-up system, and the second (also through the reducer) is an unregulated asynchronous AC motor, characterized in that, in order to quickly eliminate long-term short circuits, the unregulated motor ene energized by an intermediate relay, which is powered through gate voltage is removed from the controlled motor armature. 2. Use in the device according to claim 1, in order to shut down the irregular. accelerated feed motor shortly before the electrodes will come into contact with a memory device made in the form of a arm sitting on a slider, a pipe passed vertically (along a sliding fit), braked by a spring brake, and a spring-loaded brush passing through the tube and resting on the body of the product and carrying a coupling on the upper end opening the contacts of the end switch in the power supply circuit of the fast feed motor down.