JP2993782B2 - Sealing device for machining tank of electric discharge machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device for a machining tank of an electric discharge machine, and more particularly, to a machining liquid storage area for electric discharge machining provided above a work mounting table in the machining tank and below the table. The space between the drainage tank to be placed and the inside of the tank is closed at the time of electric discharge machining to securely seal the space between the machining liquid reservoir area and the drainage tank, and machining is performed when necessary, such as when the electric discharge machining is interrupted or completed. The present invention relates to a sealing device for a machining tank of an electric discharge machine, which secures a sufficient drainage passage from a liquid reservoir to a drainage tank and can quickly discharge a machining fluid.

[0002]

2. Description of the Related Art In an electric discharge machine, it is necessary to place a work on a table and to secure a machining liquid reservoir area in the area above the table to be filled with a machining fluid for electric discharge machining. Conventionally, a processing tank surrounding the table is fixedly arranged or vertically movable with respect to the table, and an area of a predetermined depth surrounded by the inner wall surface of the processing tank is used as a processing liquid storage area. Have been.
Here, when the processing tank is fixedly arranged, the work mounting table side is vertically movable, and when the table is fixedly arranged, the processing tank side is vertically movable. On the other hand, the worker can easily attach and detach the work. At the time of electric discharge machining, a pump, a chip filtration filter,
Filling the machining tank with machining fluid for electric discharge machining through a machining fluid supply system consisting of a pipe line, etc., and performing electric discharge machining of the workpiece by the electric discharge machining electrode in the machining fluid stored in the machining tank,
At the end of electric discharge machining or during the inspection of the electric discharge machining status during machining, the machining fluid mixed with machining powder is discharged to a drainage tank arranged below the work mounting table to empty the machining fluid reservoir area, The working fluid is recirculated from the drainage tank to the working fluid tank. In the machining tank of the above-described conventional electric discharge machine, as a sealing means for preventing the machining fluid from leaking from the machining fluid reservoir area, a sealing member fixedly arranged is provided between the table and the inner wall surface of the machining tank. A liquid seal is provided while allowing the liquid to move up and down relative to the table and the processing tank, and a separate drain hole is provided that penetrates the table surface. For example, the opening and closing of the seal lid is controlled by, for example, a bellows type actuator, so that the drainage hole is closed and the drainage is performed by opening the drainage hole.

[0003] Further, there has been a liquid discharge mechanism provided with a flexible pipe or a drain pipe for drainage.

[0004]

However, in the above-mentioned conventional sealing means for a processing tank, in the former case, it is necessary to provide two elements, a sealing material and a sealing lid, at different positions. It needs to be replaced regularly because it gradually wears out due to the relative vertical movement between the workpiece and the processing tank.The drain hole closed by the seal lid must have an extremely large hole diameter to enable high-speed drainage. Must be perforated and secured on the table surface, so that there is a problem that there is a limit. Further, providing two sealing means, a sealing material and a sealing lid, has also been a cause of increasing costs.

Further, in the latter drainage mechanism using a flexible pipe or a drain pipe, there is a limit to the hole diameter of the pipe or pipe, and again, there is a problem that high-speed drainage becomes difficult. When a pipe or a pipe is used, there is a problem that, due to an increase in the weight, the moment exerts an excessive effect on the work mounting table and adversely affects the electric discharge machining accuracy.

Accordingly, an object of the present invention is to solve the above-mentioned problems in the conventional sealing device for a machining tank of an electric discharge machine and to surely prevent leakage of machining fluid by using a single sealing means. An object of the present invention is to provide a sealing device for a machining tank of an electric discharge machine, which is capable of performing high-speed drainage at the same time as drainage and improving machining efficiency in electric discharge machining.

Another object of the present invention is to reduce the cost of a sealing device for a machining tank of an electric discharge machine by using a single sealing means and a structure for preventing the abrasion of the sealing means.

[0008]

DISCLOSURE OF THE INVENTION In view of the above-mentioned object of the present invention, according to the present invention, an electric discharge machine is fixed to a table so as to hang down in a gap having a predetermined width between a work mounting table and a machining tank. A single elastic seal body having a film-shaped portion and a column-shaped sealing portion having a raised surface extending toward the inner wall surface side of the processing tank and extending at a lower edge of the film-shaped portion is provided. When the seal action portion of the elastic seal body is pressed against the inner wall surface of the processing tank by the operation of the control means, the processing liquid reservoir region surrounded by the processing tank is sealed, and the press-contact operation by the control means is performed. When released, the seal acting portion of the elastic seal body is quickly separated from the inner wall surface of the processing tank by the hydraulic pressure acting on the film-like portion to open the gap between the table and the processing tank, and the processing liquid reservoir area From the bottom to the drain tank below the table at high speed.

That is, according to the present invention, there is provided a machining tank for surrounding a space above a work mounting table of an electric discharge machine to form a machining liquid storage area and a discharge tank provided below the work mounting table. In a sealing device for a machining tank of an electric discharge machine, the space between the work tank and the liquid tank is sealed at the time of electric discharge machining, and the seal is released at the time of non-electric discharge machining so that the machining liquid can be drained to the drain tank. A film-shaped portion that is drooped and stretched in a drainage gap between a side surface of the mounting table and an inner wall surface of the processing tank, and is integrally formed and extended to a lower edge of the film-shaped portion; And an elastic seal body having a columnar sealing action portion having a raised surface bulging toward the inner wall surface of the processing tank, and the columnar sealing action portion of the elastic seal body facing the inner wall surface of the processing tank. Advancing position to close the working fluid reservoir region with respect to the drainage tank A columnar sealing portion of the elastic seal body is retracted from an inner wall surface of the processing tank, and the processing liquid reservoir is provided via a drainage gap between a side surface of the work mounting table and an inner wall surface of the processing tank. A pressing member that moves between a retreat position that communicates the area with the drainage tank, and a sealing / drainage control unit that controls the advancement and retreat of the pressing member; A sealing device for a processing tank is provided.

[0010]

The sealing device for a machining tank of an electric discharge machine according to the present invention having the above-described structure operates the sealing and drainage control means forward to press the column-shaped sealing portion of the elastic seal body against the inner wall surface of the machining tank. Then, the working fluid storage region above the work mounting table is sealed with the drainage tank, and when the sealing and drainage control means is moved backward from the forward position to the retracted position, the elastic seal body is closed. Due to the combined force of the pressure applied to the film-like part by the upper working fluid, the columnar sealing action part of the elastic seal body quickly separates from the inner wall surface of the processing tank and drains the gap between the table and the processing tank. Since it is opened as a passage, the machining fluid can be drained at a high speed. That is, sealing and drainage can be switched according to the displacement of the single elastic seal body. Also, even when the working tank and the table move up and down relative to each other, the sealing action portion of the elastic seal body is maintained in a non-contact state with the device portion of the electric discharge machine, so that the elastic seal body does not wear out and has a long length. The service life can be ensured and the cost can be reduced by using a single component having a long service life. Hereinafter, the present invention will be described in more detail with reference to embodiments shown in the accompanying drawings.

[0011]

FIG. 1 is a sectional view showing a main part of an entire configuration of a sealing device for a machining tank of an electric discharge machine according to the present invention.
FIG. 2 is another part of the overall configuration of the sealing device for a machining tank of an electric discharge machine according to the present invention,
That is, a cross-sectional view showing a configuration example of the working fluid supply device, FIG.
Is a partially enlarged cross-sectional view showing a state in which an elastic seal body of the sealing device seals a working liquid storage region with an inner wall surface of a processing tank, and FIG. 4 is a partial perspective view showing a structure of the elastic seal body.

Referring to FIGS. 1 and 2, the electric discharge machine comprises:
It has a work mounting table 10 mounted on the top surface of a bed 8 fixed to a floor or the like at a processing site, and the work mounting table 10 has a top surface as a work mounting surface 12,
Generally, it is formed by a square metal table, and discharges a machining fluid from a machining fluid supply device described later.
One or an appropriate number of discharge ports 14 are provided. A drainage tank 20 supported by the bed 8 is provided below the work mounting table 10, and the drainage tank 20 stores therein the machining fluid for electric discharge machining when the machining fluid is discharged. To form a drain volume.

A processing tank 30 is provided so as to surround the work mounting table 10 with a gap having a predetermined width.
Is provided. In the present embodiment, the processing tank 30 is formed as a box-shaped body that surrounds the four tables and that can be moved up and down with respect to the work mounting table 10 by a drive mechanism (not shown). 32
Is arranged so as to always be located in the above-mentioned drainage tank 20, so that when the peripheral wall surface 34 of the box-shaped body moves upward, a working fluid reservoir area 36 having a predetermined depth is formed in the upper area of the table 10. Is provided. The upper opening of the machining tank is vertically opposed to a machining spindle (not shown) having machining electrodes of the electric discharge machine, and at the time of electric discharge machining, the machining spindle is located in the machining fluid reservoir area 36 through this opening. It descends and performs electrical discharge machining on the work.

A working fluid supply device 50 is provided separately from the work mounting table 10 and the processing tank 30 surrounding the work mounting table 10. This processing liquid supply device 50
Is provided with a machining fluid tank 52 for storing a machining fluid for electric discharge machining. In order to supply machining fluid from the machining fluid tank 52 to the machining fluid reservoir region 36 of the machining tank 30, the feed is driven by an electric motor M. A liquid pump 54, a filter 56 for removing foreign matter such as processing powder mixed in the processing liquid fed from the liquid feeding pump 54, and a work mounting table 1 from the filter 56.
From the inside of the working fluid tank 52, a liquid sending pipe 58 connected to the above-described working fluid discharge port 14 formed at 0, a bypass pipe 62 having a bypass valve 60 for preventing an excessive load from being applied to the fluid sending pump 54, and the like. A machining fluid supply system including a machining fluid suction pipe 66 having a strainer 64 for sucking the machining fluid into the fluid pump 54 is provided.

The processing liquid tank 52 communicates with the above-described drainage tank 20 via an appropriate conduit 68, and collects processing wastewater from the drainage tank 20 to form the above-described processing liquid supply system. To the liquid. Here, according to the present invention, the elastic seal body 40 is disposed in the gap region provided between each side surface 16 of the work mounting table 10 and the inner wall surface 34 of the processing tank 30. . As an example, the elastic seal body 40 has a film-shaped portion made of an elastic material whose one end 42 is fixed to a surface region of the table 10 by a fixing member and appropriate fixing means such as fixing bolts and which is hung down in the gap region. A sealing means comprising: a round bar-shaped or column-shaped elastic protrusion 46 provided integrally with the lower edge of the film-like portion 44 and provided along the lower edge thereof. The elastic protrusion 46 bulges from the film-like portion 44 to the inner wall surface 34 side of the processing tank 30 and the opposite side from the film-like portion 44 in the illustrated example to form a cylindrical long rod. When the raised portion 46 is pressed against the inner wall surface 34 of the processing tank 30, the gap region is sealed, so that the processing liquid storage region 36 and the table 10 are closed.
The drainage volume of the drainage tank 20 below is defined by the film-like portion 44 that closes this gap area, and is therefore completely shut off, and the processing fluid from the processing fluid reservoir area 36 to the inside of the drainage tank 20 Can be prevented. That is, the elastic protrusion 46 is a portion that functions as an elastic sealing portion.

On the other hand, when the space between the machining liquid reservoir area 36 and the drainage volume of the drainage tank 20 is cut off by the elastic seal body 40, the elastic protrusion 46 of the elastic seal body 40 is provided. Is separated from the inner wall surface 34 of the processing tank 30,
The gap region between the processing tank 30 and each side surface 16 of the work mounting table 10 is greatly opened, so that the processing liquid storage area 36 of the processing tank 30 and the drainage volume inside the drainage tank 20 are separated. Communication is established. In other words, if the machining fluid storage region 36 is filled with the machining fluid, the machining fluid can immediately flow out to the drainage tank 20 through the gap region. The elastic seal body 40 is, as shown in FIG.
It is manufactured as an integrally formed article having the elastic protrusions 4 and the elastic protrusions 46, and can be manufactured relatively easily by a molding method using a known nitrile rubber material, for example. Also, at this time, the elastic protrusion 46 is, as shown in FIG.
The inside may be formed in a solid state, or a structure in which a hollow portion is provided therein may be used as long as it has appropriate elasticity, sufficiently exerts a sealing effect, and has a function of returning to its original shape.

The elastic seal body 40 is disposed in all the gap areas when a gap area is formed between the work mounting table 10 and the processing tank 30 all around the work placement table 10. In the case where a processing tank having a configuration in which a gap area for allowing the machining fluid to flow out is not formed on one side of the four circumferences of the table is used, the elastic seal body 40 may be stretched in the three gap areas. Further, in the gap between each corner of the box-shaped processing tank 30 and the right-angled corner of the table 10, the shape of the corner of the processing tank 30 is devised, or the shape of the mold for manufacturing the elastic seal body 40 is elastically raised. What is necessary is just to make it the structure which the part 46 closely_contact | adheres at the corner part of the processing tank 30.

Now, the above-mentioned elastic seal body 40 is attached to the processing tank 3.
A means for pressing against the inner wall surface 34 of the machining tank 30 and separating from the inner wall surface 34,
According to the present invention, the sealing and drain control means 70 is used as a means for switching and controlling the sealed state between the drain and the drain volume inside the drain tank 20 and the drain state by communication as needed. Is provided. The sealing / drainage control means 70 is provided with a pressing plate so that the elastic protrusion 46 of the elastic seal body 40 can be evenly advanced and pushed from the table 10 side to the inner wall surface 34 side of the processing tank 30. The pressing plate 72 is configured to be able to move forward and backward by a bellows 74 that expands and contracts by a working fluid of an appropriate pressure supplied from a liquid distribution block 76 fixed to the upper side surface of the bed 8. That is, one end of the bellows 74 is fixed to the pressing plate 72,
Since the other end on the opposite side is fixed to the liquid distribution block 76, when the working fluid is supplied to the inside of the bellows, the other end expands and presses the pressing plate 72, so that the circular area "C" in FIG. As shown in the sealing state diagram of FIG. 3 taken out as a center, the elastic ridge 46 of the elastic seal body 40 is pressed from the table side to the inner wall surface 34 side of the processing tank 30 to perform a sealing action. is there.

On the other hand, when the working fluid is discharged from the inside of the bellows 74, as shown in FIG.
The processing liquid reservoir region 3 of the processing tank 30 is
The working pressure of the working fluid filled in the working fluid 6 acts, and the combined force of the working fluid and the pressing force applied to the elastic protruding portion 46 rapidly reduces the elastic protruding portion 46 into the processing tank 30 according to a decrease in the pressing force. The gap between the side surface 16 of the table 10 and the inner wall surface 34 of the processing tank 30 is quickly opened, and the working liquid storage region 36 and the drainage tank 2
0 is formed in communication with the inside. As a result, high-speed discharge of the working fluid is promoted.

Here, each of the sealing and drainage control means 7 described above.
As shown in FIG. 2, the working fluid for actuating 0 is supplied or recovered by a working fluid supply mechanism 80 having a separately provided working fluid tank 82. Referring to FIG. 2, the working fluid supply mechanism 8
Reference numeral 0 denotes a motor-driven working fluid supply pump 84 for pumping working fluid from a working fluid tank 82, a two-position switching type fluid switching valve 85 having a pilot pipe, and the same fluid switching valve 8
When the working fluid line 86 and the fluid switching valve 85 connected to the respective liquid distribution blocks 76 from above 5 are switched to the working fluid recovery position, the working fluid from the working fluid line 86 is collected into the working fluid tank 82. , And a recovery pipe 88 for returning. In FIG. 2, the fluid switching valve 85 is switched to the working fluid recovery position, and therefore, the working fluid is
The state in which the inside of the bellows 74 of each sealing and drainage control means 70 is collected in the working liquid tank 82 via the liquid distribution block 76, the working fluid pipe 86, the recovery pipe 88 and the like is shown. Therefore, when the elastic raised portion 46 of the elastic seal body 40 shown in FIG. 4 is pressed against the sealing position, the fluid switching valve 85 is again switched from the recovery position to the working fluid switching position, whereby each sealing and discharging operation is performed. The pressing plate 72 of the liquid control means 70 is pressed in response to the extension operation of the bellows 74.

The sealing and drainage control means 70 in the above-described configuration is one embodiment of the present invention, and
For example, a well-known hydraulic or pneumatic cylinder device is provided as a driving means for moving the pressing plate forward or backward, instead of extending or retracting the pressing plate 72 by extending or The pressing plate 72 for pressing the elastic ridge 46 of the elastic seal body 40 disposed in the cylinder may be synchronously advanced and retracted by one or more cylinder devices.

The bellows 74 in this embodiment is also formed of an elastic seal 40 stretched on each side surface 16 of the table 10.
With respect to the elastic raised portion 46, a pressing mechanism having a bellows 74 may be separately arranged in a plurality of positions.
One or two bellows 74 may be provided in a substantially central region in the length direction of the pressing plate 72 to operate the pressing plate 72,
In short, the pressing plate 72 is always in contact with the inner wall surface 34 of the processing tank 30.
While maintaining parallelism with respect to the inner wall surface 34 by pressing the elastic protrusion 46 of the elastic seal body 40 with uniform pressing force,
What is necessary is just to perform the sealing action.

[0023]

As is apparent from the above description, the present invention relates to a film-shaped portion fixed to a table so as to hang down in a gap having a predetermined width between a workpiece mounting table and a machining tank of an electric discharge machine. And a single elastic sealing body having a columnar sealing action portion extending to the lower edge of the film-shaped portion and having a raised surface bulging toward the inner wall surface side of the processing tank, When the sealing action portion of the elastic seal body is pressed against the inner wall surface of the processing tank by the operation of the control means, the processing liquid reservoir area surrounded by the processing tank is sealed, and when the pressure contact operation by the control means is released. The hydraulic pressure acting on the film-like portion causes the sealing action portion of the elastic seal body to be quickly dissociated from the inner wall surface of the processing tank, opening the gap between the table and the processing tank and opening the gap between the processing liquid reservoir area and the table below. The drain is drained to the drain tank. High-speed drainage is possible through a large gap opening as compared with the conventional configuration in which the discharge and drainage are performed, so that the setup time until the start of the next machining due to the interruption time of the electric discharge machining and the end of the electric discharge machining of one workpiece. This has the effect of shortening the time and significantly improving the EDM efficiency.

Further, according to the present invention, the action of sealing the machining fluid reservoir area of the machining tank in the electric discharge machine by using a single elastic seal body as an integrally formed elastic element, A structure that can perform both functions of draining the processing fluid from the processing tank when it is interrupted, etc., and the elastic seal is subject to abrasion even when the relative movement between the processing tank and the work mounting table moves up and down. Therefore, a long life and a cost reduction effect by reducing the number of components of the electric discharge machine can be expected.

Moreover, according to the sealing device of the present invention, the sealing and draining are stably performed by the forward operation of the elastic seal body and the backward operation utilizing the fluid pressure, so that an uneven moment force is applied to the table. It is also possible to maintain the electric discharge machining accuracy with high accuracy without receiving the electric discharge machining.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main part of an overall configuration of a sealing device for a machining tank of an electric discharge machine according to the present invention.

FIG. 2 is a cross-sectional view showing an example of the configuration of a working fluid supply device coupled to the main part in the overall configuration of a sealing device for a machining tank of an electric discharge machine according to the present invention.

FIG. 3 is an enlarged partial cross-sectional view centered on a portion “C” in FIG. 1 showing a state in which an elastic seal body of the sealing device seals a processing liquid storage region with an inner wall surface of a processing tank.

FIG. 4 is a partial perspective view showing a structure of an elastic seal body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Work mounting table 14 ... Machining liquid discharge port 16 ... Table side surface 20 ... Drainage tank 30 ... Machining tank 34 ... Inner wall surface 36 ... Machining liquid storage area 40 ... Elastic seal body 44 ... Film-shaped part 46 ... Elastic bump 50: working fluid supply device 70: sealing and drainage control means 72: pressing plate 74: bellows 76: liquid distribution block 80: working fluid supply device

Claims (1)

(57) [Claims] An electric discharge machine surrounds an upper space of a work mounting table and forms a working fluid storage area between a processing tank and a drainage tank provided below the work mounting table. Sealing at the time of electric discharge machining, in the sealing device of the machining tank of the electric discharge machine to release the sealing at the time of non-discharge machining and to allow the machining liquid to drain into the drainage tank, A film-like portion that is drooped and stretched in a drainage gap between the inner wall surface of the processing tank and a lower edge of the film-like portion is integrally formed and extended from the film-like portion to the inside of the processing tank. An elastic seal body comprising a columnar seal action portion having a raised surface that bulges toward the wall surface, and the columnar seal action portion of the elastic seal body is pressed toward the inner wall surface of the processing tank, and pressed against, An advanced position for closing the processing liquid reservoir region with respect to the drainage tank, and the elastic seal body; The column-shaped seal acting portion is retracted from the inner wall surface of the processing tank, and the processing liquid storage region is drained through the drainage gap between the side surface of the work mounting table and the inner wall surface of the processing tank. A pressing member that moves between a retreat position communicating with the pressing member, and a sealing / draining control unit that controls advance and retreat of the pressing member. Processing tank sealing device.