JPS61249218A - Wire cut electric discharge machine - Google Patents

Abstract

PURPOSE:To reduce the frictional resistance of the sealing part of a working tank by supporting a band-shaped covering body, projecting in curved form to the working tank side, in comparison with the both side edges, at the center in the direction of width of the covering body. CONSTITUTION:A steel seal 32 forming a flexible band-shaped covering body is wound and supported by the taking-up rollers 29 at the right and left edges. The intermediate part of the steel seal 32 is inserted and supported in slidable ways into a guide groove 27 formed from the side-wall outer surface of a working tank 2 and the stepped parts of the upper and lower pressing plates 28. At the near center of the steel seal 32, a fitting hole for fitting in slidable ways a lower arm 5 is formed. The steel 32 is supported, projecting in a curved form to the inside of the working tank 2 from the upper and lower edges, at the center part in the direction of width.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention involves dipping a workpiece in a machining liquid and inserting a wire electrode through the workpiece. The present invention relates to a wire-cut electric discharge machine that performs electric discharge machining by moving relative to a wire electrode while generating electric discharge.

"Conventional technology" In a wire-cut electric discharge machine, machining is performed by moving the workpiece and the wire electrode relative to each other, so machining fluid flows out from the insertion hole for inserting the wire electrode in the machining tank. Therefore, it has been difficult to control the level of the machining fluid in order to prevent aerial discharge of the wire electrode. JP-A-55-157433 discloses an electric discharge machine equipped with a pair of upper and lower wire electrode guides arranged to sandwich the upper and lower sides of a workpiece outside the machining tank.
The plate-shaped machining liquid receiver that slides on the bottom of the machining tank is attached to the electrode guide to reduce the amount of machining liquid that flows out. (Although the invention has been disclosed for the purpose of
No. 39075), a horizontally extending elongated hole is formed in the side wall of the processing tank, and the machining liquid is passed along the upper and lower sides of the elongated hole by a shield that is slidably supported in a guide groove provided in the side wall. An electric discharge machine designed to prevent leakage has been proposed. However, in this conventional electric discharge machine, as shown in Fig. ttS7 (a), the shielding body 32 made of a steel seal is wound up inside the machining tank 2, and the steel seal is wound up. Due to general characteristics, the central part of the steel seal has a seventh
As shown in Figure (b), warping occurs on the outside of the processing tank 2. When performing electrical discharge machining, the water pressure F from the machining fluid is applied to the steel seal, which increases the warping of the steel seal, which increases the frictional resistance of the seal, which in turn causes damage to the X-Y table that drives the machining tank 2. There was a problem in that it harmed movement accuracy.

[Problems to be Solved by the Invention] The present invention aims to solve the above-mentioned problems.

[Means for Solving the Problems] According to the present invention, the shield is supported at the center in the width direction in a curved manner that protrudes toward the processing tank side from both side edges thereof, and the winding of the shield is supported. There is provided a wire-cut electric discharge machine characterized in that the rotating portion is supported by the side wall of the machining tank on both sides of the elongated hole.

"Operation" According to the above configuration, the warpage of the shield does not increase due to the water pressure of the machining fluid, so the frictional resistance of the seal portion in the machining tank is reduced.

"Embodiment" Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

Now, to explain the overall configuration of the wire-cut electrical discharge machine of this embodiment, as shown in Fig. MS1, a machining tank 2 is mounted on one side of a 7-frame 1 by an X-Y table 19 horizontally front and rear and horizontally. It is movably arranged and can support the workpiece %Q with the processing IL filled inside. Above the processing tank 2, the seven frames 1 are provided with an upper seven frame 3, and an upper electrode 4 made of a conductive roller is supported at the bottom thereof so as to be movable in the vertical direction. The workpiece W passes through the side wall of processing 1fi2.
A lower arm 5 made of a conductive cylindrical body is provided on the side of the 7-frame 1 so as to extend horizontally in the lower position, and protrudes from the side of the 7-frame 1 while being insulated from the 7-frame 1. A lower electrode id 6 consisting of a roller is supported in an insulated manner with respect to the lower electrode 7-m 5.

At the top of the seven frames 1, there is a supply device f! for supplying the wire electrode 7 made of metal wire. 18 is provided, and a winding device 9 for winding up the wire electrode 7 is provided at the lower part of the seven frames 1. Then, the wire electrode 7 fed out from the supply device fia is moved to the guide roller 10.
, the upper electrode id 4, the lower electrode id 6 and the guide roller 11 to the winding device fi9, and both electrodes id 4,
It is designed to be continuously supplied onto the workpiece W during the period of 6.

A power supply circuit is connected between the wire electrode 7 and the workpiece W, and the wire electrode 7 and the workpiece W are connected to each other. , W are repeatedly generated in the machining gap, and the workpiece W is machined using the discharge energy.

That is, in the power supply circuit, a source terminal of a field effect transistor 13 is connected to one terminal of the DC power supply 12, and a switching control circuit 14 for controlling the switching operation of the transistor 13 is connected to its date terminal. . A diode 15 and a resistor 16 are connected between the drain terminal of the field effect transistor 13 and the other terminal of the power supply 12 for erasing the reactance voltage caused by the switching operation of the transistor 13. The workpiece W is connected to the inlet terminal of the power supply circuit via the conductive lower part 5,
The wire electrode 7 is connected to the other terminal of the power supply circuit via the lower electrode 6.

A pump 17 is connected to the lower arm 5, and the operation of this pump 17 causes machining fluid to be filled into the machining tank 2 from the machining fluid tank 18 through the inside of the lower arm 5 at the start of the machining process. Wire electrode 7 inside
Machining 8 in the machining gap between and the workpiece W! It ends by supplying L.

Next, the main feature of the present invention is l! The structure of the seal between the long hole and the shield in the machining tank 2 will be described in detail with reference to FIGS. 2 to 5.

Now, in this embodiment, on one side of the processing tank 2,
A long hole 21 for inserting the lower arm 5 is formed near the lower end of the II wall so as to extend substantially horizontally, and a winding portion is formed on the outer surface of the side wall of the processing tank 2 on both left and right sides of the long hole 21. A steel housing 25 is provided in each case. A groove 23 is formed outside the elongated hole 21 and extends along the elongated hole 21 to catch and stop leakage water.
A drain port 24 is formed in the side wall of the processing tank 2 so as to communicate with one end of the groove portion 23 .

A pair of upper and lower presser plates 28 are hooked to both steel plates 25 attached to the outer surface of the side wall of the processing tank 2 on both sides of the elongated hole 21, and an opening 26 is formed corresponding to the elongated hole 21. has been done. And Fig. 4 and #S
As shown in Fig. 5, the processing tank 2 is
A pair of guide grooves 27 extending horizontally along the top and bottom of the long hole 21 are formed on the outer surface of the III wall.

As shown in FIG. 3), a housing recess 22 is formed inside the steel housing 25.
A cylindrical take-up roller 29 is rotatably supported within the roller 2 . In this embodiment, the upper and lower rotating shafts 31 of the winding row 229 are supported by the lower and upper walls of the accommodation recess 22 in the steel housing 25, and
As shown in the figure, a housing bushing 30 is inserted into the earthen wall of the steel housing 25, in space with the rotating shaft 31.

On both the winding rollers 29, steel seals 32 forming flexible band-like shields are attached to the winding rollers 2 at both left and right ends.
9, and the intermediate part of the steel seal 32 is connected to the outer surface of the side wall of the processing tank 2 and the stepped part 4 of the upper and lower presser feet @2B.
1) is slidably inserted and supported within the guide lI27 formed by the guide lI27. As shown in FIG. 2, a gasket 40 is attached to the (II wall) of the stepped portion 41.
The seal receiver 34A is made of flexible synthetic a (grease).
are fitted, sandwiching the steel seal 32 and seal receiver 34.
The seal receivers 34A and 34B are fixed to the periphery of the through hole 33 by fitting the seal receiver 34B to the outer end of the seal receiver A and screwing a plurality of screws 36 into the seal receiver 34B. At the center of the seal receivers 34A and 34B, fitting holes 35 and 37 are formed in the shape r for slidably fitting the lower arm 5.
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An annular pipe seal 38 made of a non-breathable closed-cell foam material is provided, which adheres closely to the field.

In addition, in FIG. 2, the pipe seal 38 is shown taken out from the fitting hole 35.

Here, in this embodiment, the steel seal 3
2 is supported in a curved manner inwardly of the processing tank 2 at its center in the width direction than both upper and lower edges. *In addition, the steel seal 32 in this embodiment is a winding roller 29 which forms a winding part by its own elastic force! It has the property of being wound twice, and when the steel seal 32 is moved relative to the processing tank 2, it is unwound at one winding part, and the other winding part is unwound by its own elastic force. It is designed to be rolled up.

In the above configuration, the steel seal 32 is processed'WI2
2, first place the outer seal receiver 34B on the outer periphery of the lower arm 5 so as to face the processing tank 2 side, and then insert it into the through hole 33 of the steel seal 32. The tip of the lower arm 5 is passed through the lower arm 5, and finally, the seal receiver 34A with which the pipe seal 38 is integrated is inserted into the lower arm 5 toward the outside of the processing tank 2. Then, as shown in FIG. 4, the tip of the inner seal receiver 34A is inserted through the steel seal 32 and assembled into the inner diameter recess of the outer seal receiver 34B, and the two screws 36 are screwed together as shown in FIG. The seal receivers 34A and 34B are tightened and fixed to the steel seal 32. *In addition, the upper and lower presser plates 28, which are integrally fixed to the left and right steel housings 25 by screws (not shown), are attached to the outer surface of the side wall of the processing tank 2 by a large number of screws 39, as shown in FIGS.
A cotton layer is applied as shown in FIG.

When the machining tank 2 is filled with machining liquid and electrical discharge machining is performed, when the lower arm 5 is relatively moved in the X direction in FIG. 3 as the machining tank 2 moves in the horizontal direction, the steel seal 32 is also moved in the same direction and is wound up or rewound by the winding rollers 29 in the steel housings 25 at both ends.

At this time, as shown in FIG. 5, the friction force between the steel seal 32 and the water pressure F caused by the processing fluid in the processing tank 2 and the outer surface of the wall or the inner surface of the presser plate 28 is reduced, so that the steel seal 32 is The seal 32 slides very easily within the guide groove 27 as the lower arm 5 moves relative to the X direction. A small amount of machining fluid leaking from the machining WJ2 through the gap between the guide groove 27 and the steel seal 32 is collected by the m portion 23 and returned to the machining fluid tank 18 through the water drain port 24.

Furthermore, when the lower arm 5 moves in the Y direction, the lower arm 5 moves toward the seal receiver 34A on the steel seal 32.
The pipe is slid along the fitting hole 35 of the pipe and is held in a sealed state by the pipe seal 38.

(Numerical performance example) Regarding the frictional resistance of the steel seal 32 in the guide groove 27, a performance example of this embodiment is shown in FIG. 6 in comparison with the conventional configuration.As shown in FIG. The frictional resistance of the steel seal increases when the water level of the machining fluid in the machining tank is gradually raised from a dry state to a wet state, and at a water level of 200 m, the frictional resistance is approximately 5 K.
, f, but according to the example of the present invention, the frictional resistance did not increase even as the water level rose, and the frictional resistance at a water level of 200 mm was about I Kgf. Therefore, the effect of this embodiment is extremely significant.

"Other Embodiments" In the above embodiments, the shield that forms the seal of the long hole 21 formed in the side wall of the processing tank 2 is constructed of the steel seal 32 made of steel material, but it may be made of a material such as synthetic resin. It is also possible to replace it with a band-like member having flexibility of 1°. *In addition, in the present invention, it is important that the warpage of the steel seal 32 and other shielding bodies curves and protrudes toward the processing tank 2 side.
The winding or unwinding direction of the shield can also be on the processing tank 2 side.

"Effects" As described above, since the electric discharge machine of the present invention has the above-mentioned advantages, it is possible to reliably prevent machining fluid from leaking from inside the machining tank, and the long holes in the sealing part of the machining tank can It is possible to reduce the frictional resistance between the shielding member and the shielding body, and as a result, the motion accuracy of the X-Y table can be maintained well, and there are excellent effects such as improving the accuracy of electrical discharge machining.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing the overall configuration of an embodiment of the present invention, FIG. 2 is an exploded perspective view of a sealing part that constitutes the main part of the embodiment,
Figure 3 is a cross-sectional view of the seal part, Figure 4 is a longitudinal cross-sectional view, and Figure 5 is a vertical cross-sectional view of the seal part.
The figure is a vertical sectional view showing the installation status of the steel seal, No. 6
The figures are characteristic diagrams showing numerical performance examples, #7 diagrams (a) and (b)
1 is a horizontal cross-sectional view and a vertical cross-sectional view showing a conventional configuration. 1... Frame, 2... Processing tank, 21... Long hole,
25... Steel housing, 27... Guide groove, 3
2...Steel seal. W: Workpiece, L: Processing liquid. Agent: Patent Attorney Isamu Goto No. 412 No. 50 No. 6

Claims (1)

[Scope of Claims] A long hole extending horizontally is formed in the side wall of a processing tank in which the workpiece can be immersed, and is slidably supported in a guide groove provided in the side wall along the top and bottom of the long hole. In a wire-cut electrical discharge machine having a band-shaped shield having flexibility, the shield is supported in a widthwise central portion of the shield in a curved manner protruding toward the machining tank from both side edges thereof, and A wire-cut electric discharge machine characterized in that the winding portion of the shield is supported by the side wall of the machining tank on both sides of the elongated hole.