JP3112645U - Electric discharge machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric discharge machine equipped with an electric discharge detector for detecting electric discharge that causes generation of a flame by detecting ultraviolet rays emitted from an electric discharge phenomenon.
A container capable of transmitting ultraviolet rays is provided, and the container includes an inert gas sealed in an airtight manner, a cathode, and an anode, and the space between the cathode and the anode is provided outside the container. Arbitrary pulse voltage is applied in the control unit, discharge detector for electric discharge machine that detects the occurrence of discharge using photoelectric effect by ultraviolet ray, electric discharge machining part that performs machining by electric discharge, and ultraviolet ray detection A discharge detecting means for detecting a fire by doing, a control section for controlling the fire discharge detection section, and a management section for controlling the operation of the electric discharge machine, the discharge detection means, and the control section, Electric discharge machine.
[Selection] Figure 2

Description

  The present invention relates to an electric discharge detector for detecting electric discharge and an electric discharge machine having the electric discharge detector.

  Currently, there is an electric discharge machine as a metal processing machine. An electric discharge machine performs metal processing using an electric discharge phenomenon, and is used when performing highly accurate processing.

  However, in an electric discharge machine, a highly ignitable machining fluid such as kesilon is used, and there are many cases in which a fire is generated by igniting an electric spark due to electric discharge.

  As a countermeasure, conventionally, infrared rays were used to suppress the initial fire. However, since this infrared sensor can detect only after a flame has occurred, it cannot detect a discharge that causes ignition. In addition, the infrared sensor is susceptible to ambient light and may malfunction.

  In order to solve such inconveniences, an object of the present invention is to provide a discharge detector that detects the cause of fire by detecting ultraviolet rays radiated from a discharge phenomenon in an electric discharge machine.

  Furthermore, it aims at providing the electric discharge machine provided with the said electric discharge detector.

  In order to achieve the above object, the device of claim 1 includes a container that can transmit ultraviolet rays, and the container includes an inert gas sealed in an airtight manner, a cathode, and an anode, An arbitrary discharge voltage is applied between the cathode and the anode in a control unit provided outside the container.

  Further, the invention of claim 2 is an electric discharge machining unit that performs machining by electric discharge, an electric discharge detection unit that detects electric discharge by sensing ultraviolet rays, a control unit that controls the electric discharge detection unit, the electric discharge machining unit, An electric discharge machine comprising a management unit that controls operations of the electric discharge detection means and the control unit.

  More preferably, the electric discharge detector may be the electric discharge detector for an electric discharge machine according to claim 1. In addition, the discharge detector of the present invention can detect ultraviolet rays generated from a flame and can also be a flame detector.

  According to the above-described present invention, in the normal operation of the electric discharge machine, the discharge portion is below the machining liquid surface, and the ultraviolet rays are absorbed by the machining liquid. Therefore, the discharge detector does not output an abnormal signal. When the discharge part reaches the surface, ultraviolet rays are detected and an abnormal signal is generated. Of course, it also detects when it becomes flame. Since it is equipped with facilities that detect discharges that are difficult to detect with the naked eye and infrared sensors, it is possible to provide an excellent electrical discharge machine for preventing fire accidents, rapid digestion activities, and secondary disaster prevention.

  Hereinafter, the electric discharge detector and electric discharge machine of this invention are demonstrated with the example of illustration.

  A discharge detector is shown in FIG. The outside is covered with quartz glass 2. Inside the quartz glass 2, a cathode (photocathode) 3 and an anode 4 that are sensitive only to ultraviolet rays are disposed apart from each other, and a gas such as argon is sealed therein. Conductive wires are respectively connected to the cathode 3 and the anode 4, and these conductive wires extend from the bottom of the quartz glass 2 to the outside and are connected to the control unit 5.

The discharge detector 1 in the present invention detects the occurrence of discharge by the photoelectric effect. The operating principle is as follows.
In the discharge detector 1, a pulse voltage is applied in advance between a cathode (photocathode) 3 and an anode 4 that are sensitive only to ultraviolet rays. In this state, when a discharge due to hydrogen occurs within the effective detection range of the discharge detector 1, ultraviolet rays are emitted from the discharge occurrence location. When the emitted ultraviolet light is incident on the cathode 3 of the discharge detector 1, photoelectrons are emitted from the cathode 3 by the photoelectric effect. Photoelectrons are attracted to the anode 4 by an electric field. Here, when the applied voltage is increased and the electric field is increased, the photoelectrons are sufficiently accelerated to collide with gas molecules in the tube until they are ionized. Of the electrons and positive ions generated by ionization, the electrons further collide and ionize with other gas molecules and reach the anode 4. On the other hand, positive ions are accelerated toward the cathode 3 and collide with the cathode 3 to generate many secondary electrons. By repeating this, a large current flows abruptly between the cathode 3 and the anode 4, and a conductive state is established.

  When this discharge current reaches a certain condition, the control unit 5 outputs a result of “discharge detection”, but this condition can be changed by the control unit 5. Specifically, the “discharge detection” output condition may be, for example, “output a result of“ discharge detection ”when a discharge current of 50 mA is detected over 10 steps”. For example, “10” in “10 steps” may be changed to “5”, or “50” in “50 mA” may be changed to “100”. Other parameters that can be changed include a pulse voltage waveform, a pulse width, and a cycle.

By making such a setting change, the discharge detector 1 can detect only the ultraviolet rays radiated from the discharge phenomenon. This is because the discharge detector 1 of this embodiment outputs “discharge detection” by detecting ultraviolet rays as described above, and cannot determine whether or not the source of the ultraviolet rays is a discharge. Because. An example of this is lightning.
When thunder occurs, ultraviolet rays contained in the lightning are emitted. Then, it is assumed that the discharge current is detected for only one step by the incidence of this ultraviolet ray on the present discharge detector 1. At this time, if the minimum number of steps is not set as a condition for outputting “discharge detection”, the control unit 5 outputs “discharge detection” by detecting one step at the time of occurrence of lightning. .
However, if the output condition is set to “output the result of“ discharge detection ”when discharge current is detected continuously for 5 steps or more”, the malfunction of “discharge detection” due to lightning in this example will occur. do not do.
There are many other factors that affect output conditions, such as sunlight and halogen lamps. Therefore, the output conditions need to be changed as appropriate according to the usage environment.

FIG. 2 is a schematic configuration diagram showing an embodiment of an electric discharge machine provided with the electric discharge detector 1. FIG. 3 is a block diagram showing an embodiment of an electric discharge machine according to the present invention.
The electric discharge machine 6 mainly includes a machining electrode 7 that performs electric discharge, a table 9 that supports a workpiece 8, a container 11 that is filled with a machining liquid 10, and an electric discharge detector 1 that detects electric discharge. The control unit 12 controls the discharge detector 1. And the management part 13 which controls operation | movement of these facilities is provided. The management unit 13 is further connected to a line network such as a telephone line or the Internet.

  When the machining electrode 7 is exposed from the machining liquid 10 while machining the workpiece 8, there is a possibility that electric discharge is generated and the machining liquid 10 is ignited. The discharge detector 1 detects discharge before ignition and can stop the discharge by stopping the discharge.

  In the present embodiment, the discharge detector 1 is installed at a place as shown in FIG. 2, but the place can be changed as appropriate as long as the machining electrode 7 can be generally seen. Moreover, since the effective range which can detect discharge is limited, the number of the discharge detectors to install is changed suitably according to the magnitude | size of an electric discharge machine.

As described above, the result of “discharge detection” is output to the management unit 13 in the control unit 12, and the management unit 13 may stop the discharge operation of the processing electrode, for example, according to this output. By taking such a configuration, the spread of damage can be prevented.
In addition, the management unit 13 may be configured to warn danger in the vicinity using light and sound. Specifically, it is conceivable to operate a rotating lamp, a siren or the like. By adopting such a configuration, it is possible to prevent the spread of damage by warning nearby residents of danger and calling for prompt evacuation.

It is a perspective view which shows an example of the form which implements the discharge detector of this invention. It is an external view which shows an example of the form which implements the electric discharge machine of this invention. It is a block diagram which shows an example of the form which implements the electric discharge machine of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric discharge detector 2 Quartz glass 3 Cathode 4 Anode 5 Control part 6 Electric discharge machine

Claims (3)

A container that can transmit ultraviolet rays
In the container,
An inert gas sealed hermetically;
A cathode,
With an anode,
An arbitrary pulse voltage is applied between the cathode and the anode in a control unit provided outside the container. A discharge detector for an electric discharge machine. A machining electrode for machining by electric discharge;
A discharge detecting means for detecting discharge by detecting ultraviolet rays;
A control unit for controlling the discharge detection means;
An electric discharge machine comprising: a management unit that controls operations of the electric discharge machining unit, the electric discharge detection means, and the control unit. The electric discharge machine according to claim 2, wherein the electric discharge detection means is the electric discharge detector for electric discharge machines according to claim 1.

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