JPS5847294B2 - How to use the wheel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operation control method and apparatus for an electrolytic grinding device having a wheel-shaped processing electrode, and in particular, the current-carrying part of the processing electrode located near the wheel-shaped processing electrode is connected to an electrolytic processing liquid. The present invention relates to an operation control method and device that can easily prevent electrolytic corrosion without providing a complicated mechanical seal or the like to prevent the intrusion of electrolytic processing fluid.

As is well-known, electrolytic grinding machines have extremely good machinability for grinding difficult-to-grind materials, but on the other hand, they require a spindle with a special insulation mechanism to supply electricity to the processing electrodes, making it difficult to grind materials that are difficult to grind. When converting a disk into an electrolytic grinder, the spindle mechanism requires major modification, which increases the cost of modification.

For this purpose, an apparatus has already been proposed in which the processing electrode is not energized via a spindle, but instead is provided with a separate current-carrying section, and the current is passed directly through the current-carrying section.

With this kind of equipment, even when converting a normal grinder into an electrolytic grinder, there is no need for extensive modification, and it is possible to simply add a current-carrying part to the processing electrode and make the processing tank etc. into an electrolytic corrosion-resistant tank. It is good and can be modified at low cost.

The electrolytic grinding apparatus as described above will be explained with reference to FIGS. 1 and 2. In the figures, reference numeral 1 denotes a main body of the grinder, which is provided with a re-movement table 2 on its upper surface, to which a workpiece 3 is attached.

Further, a spindle head 5 is attached via a support 4, and a wheel-shaped conductive processing electrode 7 is attached to the tip of the spindle 6.

8 is a spindle motor that rotationally drives the spindle 6.

The above structure is the same as that of a normal grinder, but in order to make it an electrolytic grinder, the processing electrode T is provided with a current-carrying portion 9.

The current-carrying portion 9 is supported by a machining electrode cover 10 that is fixed to the spindle head 5 and surrounds the machining electrode 7 .

Reference numeral 11 denotes a power supply device, and a power supply terminal is connected to the processing electrode 7 and the workpiece 3.

The processing electrolyte is contained in the tank 12, and the tank 1
The machining electrolyte is supplied between the machining electrode 7 and the workpiece 3 by injecting the machining electrode 7 and/or the workpiece 3 from the supply pump 13 installed in the workpiece 2 through the supply on-off valve 14 and the supply nozzle 15. let

16 is a pump motor for driving the pump 13.

The detailed structure of the current-carrying section 9 is shown in FIG.

First, the processing electrode 7 is attached to the insulating flange 1 with respect to the spindle 6.
6. It is attached via a current-carrying bush 17.

18 indicates nuts.

A current-carrying ring 19 is attached to the current-carrying bush 17.

A liquid drain ring 19a is formed on the outer periphery of the current-carrying ring 19.

A brush 21 supported at the center of a current-carrying section main body 20 is brought into contact with the current-carrying ring 19 via a spring 22 .

The current-carrying unit main body 20 is attached to the cover 10 with an insulating bolt 24 via an insulating plate 23, and is connected to a terminal of the power supply device 11 with a lead wire 25.

Further, a liquid draining ring 20a is formed on the outer periphery of the current-carrying part main body 20, and a wear-resistant seal ring 26 made of Teflon or nylon is installed between the brush 21 and the current-carrying ring 19 in the groove. A spring 27 provides compression.

The ring 26 is for preventing the processing electrolyte from flowing into the gap between the current-carrying portion main body 21 including the brush 21 and the current-carrying ring 22.

With the above configuration, during grinding, the spindle motor 8 rotates the processing electrode, the power supply 11 supplies electricity, and the pump 13 supplies processing electrolyte to perform electrolytic grinding.

However, the following problems occur during electrolytic grinding.

That is, when the electrolytic solution or electrolytic sludge sprayed from the nozzle 15 enters between the current-carrying part body 20 or the brush 21 of the current-carrying part 9 and the current-carrying ring 19, the brush 21 and the current-carrying ring 19 are electrolytically corroded by the machining electrolyte. This results in significant wear and tear.

This state is exactly the same as during electrolytic grinding where voltage is applied from the power supply via the processing electrolyte, and the wear is large.

For this purpose, the drain ring 19a is provided as described above. 20a or a seal ring 26 is provided, but it is not sufficiently effective, and in order to completely prevent the electrolyte from entering, a more complicated labyrinth or mechanical seal mechanism must be added.
This equipment had the disadvantage of being expensive.

Therefore, various considerations regarding the phenomenon of electrolyte intrusion into the current-carrying portion 9 show that while the machining electrode 7 is rotating at high speed, the electrolyte is dispersed from the outer periphery due to centrifugal force, and the liquid draining ring 19
This also works effectively and there is almost no intrusion of the electrolyte, but if the electrolyte is supplied and injected when the spindle 9 is stopped or the rotation speed is low, the electrolyte stuck to the surface of the processing electrode 7 will be removed. It was confirmed that the liquid flowed down, was transmitted, and entered the gap surface of the current-carrying part through the seal part.

An object of the present invention is to provide an operation control method and device for an electrolytic grinding machine that can easily prevent electrolyte from entering the gap between current-carrying parts, based on the consideration of the electrolyte intrusion phenomenon described above.

In accordance with the above object, the present invention rotates a wheel-shaped machining electrode relative to a workpiece and supplies a machining electrolyte to perform electrolytic grinding, when the machining electrode rotationally driven by a spindle motor stops; Alternatively, an operation control method is provided in which the electrolyte is supplied by operating the pump motor or controlling the opening and closing of the valve 14 only during periods when the pump motor is rotating at a sufficient rotation speed, except during transient low-speed rotation during start and stop. a spindle motor that rotates the machining electrode to perform the above-mentioned operation control method. The on-off relay control circuit for the on-off relay for the pump motor includes contacts that start and stop the pump motor. and a time-limited relay such as a timer that operates after a period of time for the rotation speed to increase after the spindle motor has started, or a contact a of a relay that is operated by a governor switch connected to the spindle motor, as a contact element. Moreover, the switching relay control circuit for the switching relay for the spindle motor uses contact elements that start and stop the spindle motor and the a contact of the switching relay for the pump motor, which operates when the pump motor is operated, for example. During electrolytic grinding, when the rotation speed of the processing electrode is not sufficiently established, the pump motor will not start even if an attempt is made to start it, and the electrolyte supply will not start until the rotation speed has been sufficiently established. The pump motor can be started immediately, and even if an attempt is made to stop the spindle motor while the machining electrolyte is being supplied, the spindle motor will not stop, and the spindle motor can only be stopped once the pump motor is stopped and the machining electrolyte supply stops. The gist of this is that

The method and apparatus of the present invention will now be described in accordance with the illustrated embodiments.

In FIG. 3, the spindle motor 8 and the pump motor 16
There is an electromagnetic switch (CRI) in the main circuit.

(CR2) are provided, and each switch is operated by a switching relay CR1, CR2.

In addition, the relay contacts (CR
I).

(CR2) are all a contacts.

The relay control circuits of the opening/closing relays CR1 and CR2 are constructed as follows.

First, for the open/close relay CR1 for the spindle motor 8, start button switch PS1 and stop button switch P are connected.
S2 are connected in series and connected between the power supplies 28 of the control circuit.

Further, a self-holding contact (CRI) is connected in parallel with the start button switch PS1, and a contact (CR2) of the opening/closing relay CR2 is connected in parallel with the stop button switch PS2, and this circuit configuration also provides an OR circuit.

Furthermore, a time limit relay TR such as a timer is provided between the power supply 28 and in series with the relay contact (CR1).

On the other hand, for the opening/closing relay CR2 of the pump motor 16, a start button switch PS3 and a stop button switch PS4 are provided.
and the contact point ('TR) of the time limit relay TR are connected in series between the power supply 28, and this circuit configuration forms an AND circuit.

Self-holding contact (CR2) on start button switch PS3
are connected in parallel.

Further, a solenoid 14a that operates the on-off valve 14 for supplying the machining electrolyte is connected between the power supply 28 and the relay contact (CR2) in series.

In addition, the time limit of the time limit relay TR is almost the same as the spindle motor 8.
is set to the time it takes for the engine to rise from startup to steady rotational speed.

With the above circuit configuration, when the start button switch PS is closed during electrolytic grinding, the opening/closing relay CR1 is energized.

Therefore, the electromagnetic switch and relay contact (CRI) are self-retaining upon closing.

As a result, the spindle motor 8 is started to rotate the processing electrode 7, and the circuit of the time limit relay TR is closed.

After a certain period of time when the rotational speed of the spindle motor 8 increases, the time limit relay contact (TR) closes.

In this state, the start button switch PS of the pump motor 16
3, the open/close relay CR2 operates and each contact (C
Familiarize yourself with R2).

Therefore, the opening/closing ring-CR2 circuit is self-maintained and the pump motor 16 is started.

At the same time, the solenoid 14a is energized to open the on-off valve 14 and supply the machining electrolyte.

During this starting operation, if the spindle motor 8 is stopped or the rotational speed has not increased and the contact (TR) has not closed yet, even if the start button switch PS3 is opened, the open/close relay C will not be activated.
R2 does not work.

That is, the machining electrolyte can be supplied only after the machining electrode rotation is established.

Next, during electrolytic grinding, even if you open the stop button switch PS2 to stop only the spindle motor 8 while supplying the machining electrolyte, the parallel contact (CR2) remains closed, so the spindle motor 8 is not stopped.

When stopping, first open the stop button switch PS4 in the control circuit of the pump motor opening/closing relay CR2, then the opening/closing relay CR2 becomes de-energized and each contact (CR2)
open.

Therefore, the on-off valve 14 is closed, the processing electrolyte supply is stopped instantaneously, and the pump motor 16 is also stopped.

Next, if the stop button switch PS2 of the spindle motor 8 is opened, the spindle motor 8 can be stopped because the relay contact (CR2) is already open.

In the circuit of FIG. 4, instead of the time limit relay TR of FIG. 3, a relay OR is inserted and connected between the power supply 28 in series with a governor switch GS that interlocks with the spindle motor 8, and the contact (OR) of the relay GR is an open/close relay. It is connected in series with CR2, and when the rotational speed of spindle motor 8 increases sufficiently, governor switch GS closes and relay OR operates.
Close the contact (GR).

Therefore, it works in the same way as the time limit relay TR in FIG.

Other circuit configurations and operations are also similar to the embodiment shown in FIG.

In each of the above embodiments, the start and stop button switch PS1
- Although PS4 is shown as having each independent manual switch, it is also possible to use a single changeover switch for start and stop operations, as well as a start and stop switch for the spindle motor 8 and a start/stop switch for the pump motor 16. A program control structure may be used in which the operation control is regulated according to the operation control program described above.

For this program control, the circuit configuration of each of the embodiments described above is configured as a conditional control circuit to implement the operation control method defined as described above.

FIG. 5 shows the rotation of the spindle motor 8 and the flow rate of the machining electrolyte supplied by the pump motor 16 over time in each of the embodiments described above.

As is clear from the figure, the processing electrolyte is applied to the spindle motor 8,
That is, it is supplied only while the rotational speed of the processing electrode 7 is sufficiently stable.

In addition, the dotted line part in the curve of the processing electrolyte supply amount in the figure is a characteristic curve when the on-off valve 14 is not installed in front of the nozzle 15 and supply and stop control is performed only by the pump motor 16. When starting and stopping supply, a slight delay occurs due to inertia due to the length of the supply pipe.

In particular, the delay in running out of liquid when the pump motor 16 is stopped is
If the delay is small, there is no practical problem, but if the delay is large, it becomes a problem, so it is better to install an on-off valve 14.

As described above, according to the present invention, the supply of the machining electrolyte is restricted to occur only when the machining electrode rotates, so the supplied electrolyte is dispersed in the outer circumferential direction by the centrifugal force of the machining electrode, and the electrolyte is The effect of reliably preventing intrusion into the gap surface of the current-carrying part can be obtained.

What's more, wheel-type electrolytic grinding is excellent because it can be easily carried out without additionally installing a particularly complicated labyrinth or mechanical seal mechanism, prevents galvanic corrosion of current-carrying parts, and maintains the long life of brushes and current-carrying rings. A device operation control method and device can be provided.

[Brief explanation of the drawing]

Figure 1 shows the constituent countries of the electrolytic grinding device, Figure 2 is a detailed sectional view of the current-carrying part in Figure 1, Figures 3 and 4 are electrical circuit diagrams of different embodiments of the invention, and Figure 5. FIG. 2 is an explanatory diagram of the operation according to the present invention. 3...Workpiece, 7...Wheel-shaped processing electrode, 8...Spindle motor, 9...
... Current carrying part, 11 ... Power supply device, 12 ...
...Processing electrolyte tank, 16...Pump motor, CR1...Spindle motor opening/closing relay,
CR2...Pump motor open/close relay, (CR
I), (CR2)...""A contact of open/close relay, P
Sl. PS3...Start switch, PS2. PS4...
...stop switch, TR...time limit relay,
GS・・・Governor switch, GR・・・・・・
Governor switch relay.

Claims (1)

[Claims] 1. Rotating a wheel-shaped processing electrode with respect to a workpiece,
And when supplying a machining electrolyte to perform electrolytic grinding,
Operation of an electrolytic grinding apparatus having a wheel-shaped machining electrode, characterized in that the supply of the machining electrolyte is controlled so that the machining electrolyte is supplied only during the period when the wheel-shaped machining electrode is rotating at a desired rotation speed or higher. Control method. 2. In the device used in the operation control method according to claim 1, an opening/closing relay provided for the spindle motor for rotating the wheel-shaped processing electrode and the pump motor for supplying the processing electrolyte; AND the stop contact and the contact that operates when the rotation of the spindle motor increases.
The present invention is characterized by comprising a control circuit for a pump motor opening/closing relay configured in a circuit, and a control circuit for a spindle motor opening/closing relay in which an OR circuit is configured with contacts that operate during start, stop, and operation of the pump motor. An operation control device for an electrolytic grinding machine that has a wheel-shaped processing electrode.