JPS59192424A - Electric discharge machine - Google Patents

Abstract

PURPOSE:To prevent the deviation of core, etc. by providing a block having a dovetail-shaped part, which can be engaged with an electrode holder with a mated configuration and dimensions, on the lower part of a spindle head ad enabling said electrode holder to be held under pressure, in an electric discharge machine having an automatic electrode replacing device. CONSTITUTION:A block 3 having a female dovetail shaped part 4 is fixed to an electrode surface table 2 mounted on a spindle head 1 in an electric discharge machine, and a male dovetail shaped electrode holder 5, having an engaging member 26 which can be engaged with the arm of an automatic electrode replacing device, is provided so as to be freely removably engaged with the block 3. On one side of said dovetail shaped part 4 is provided a slider piece 6, which can be moved toward the part 4 by means of the operation of a pair of pistons 10. Both pistons 10 are externally energized by means of springs and, when a pressurized fluid is removed from a cylinder chamber 24, a piston 18 is moved downward due to a coned disk spring 20 and compresses a cylinder chamber 17, causing the pistons 10, i.e., the slider piece 6, to be advanced to hold the electrode holder 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an automatic electrode exchange device included in a numerically controlled (No.) electric discharge machining apparatus.

The automatic electrode exchange device used in conventional numerically controlled electric discharge machining equipment has an electrode holder automatic clamp device installed at the tip of the spindle head and an electrode storage magazine installed on the side of the machine body, and a transfer arm is used to connect the electrode holder automatic clamp device to the side of the machine body. Electrodes were attached to the spindle head and stored in an electrode storage magazine. The electrode holder automatic clamping device is equipped with a reference plane for the x, y, and z axes and a shank that protrudes in the Z-axis direction (upward) necessary for clamping, or a retaining part called a Solstad bolt. This was the general configuration. For this reason, in order to attach the electrode holder automatic clamp device to all spindle heads, it was necessary to insert the electrode holder by turning from the bottom to the top. This requires adding vertical movement to the transfer arm, and when positioning the electrode holder on the ramp, the electrode is set to a position away from the workpiece by the distance it is moved in the ZII11 direction to be lifted.

Normally, when numerically controlled electrical discharge machining is performed using an automatic electrode changer, a long electrode is used to initially set the entire distance between the electrode and the workpiece, so many machines including short electrodes are used. In the case of individual machining, combination machining, etc., a sufficient machining depth may not be obtained within the spindle stroke. This eave is the shift amount mentioned above (usually about 60 to 7 Q 111
1) is greatly affected. Furthermore, when transporting the polarization holder from the magazine to the spindle head, the polarization holder is fully lowered by the shift amount mentioned above and moved directly below the spindle head. In some cases, interference may occur, and in order to completely avoid this, it was necessary to give the transfer arm complex sequential control movements such as up and down, rotation, forward movement, and backward movement.

This means that the structure of the transfer arm *ai, m
.

Not only is it expensive, but it also takes a long time to replace the electrodes, which leads to a decrease in productivity. In addition, the electrode holder in the above-mentioned conventional automatic electrode exchange device has a diameter of approximately 20 mm due to limitations in the outer diameter of the shank or the rigidity of the Solstad bolt. It has the disadvantage that it is almost difficult to apply it to graphite electrodes having one or more large electrodes or a large area of about 100 cIIt or more.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and is a discharge discharge device that uses an electrode holder having a female dovetail shape as a medium and is equipped with an automatic electrode exchange device that is conveyed between a spindle head and a magazine. In processing equipment,
The electrode holder automatic clamping device mounted on the spindle head side has a female dovetail shape that forms a male and female dimensional engagement relationship with the electrode holder having a female dovetail shape. The side wedge-shaped portion is provided with at least one clamp piston that is operated by static pressure fluid in a direction perpendicular to the direction in which the electrode holder having the female dovetail shape is carried in and out, and the tip of the crank piston is Said female dovetail shape! The static pressure fluid is configured to hold the female dovetail-shaped electrode holder in a pressurized state while the electrode holder is being clamped, and the static pressure fluid forms a part of a wedge shield-shaped portion formed by the block. The purpose is to develop electrical discharge machining equipment that can significantly increase the rigidity of the electrode exchange device and make maximum use of the effective stroke of the spindle.

An embodiment of the present invention will be described below with reference to the drawings. 1st
FIG. 1(a) is a partially cutaway front view of an automatic electrode holder clamping device in an electric discharge machining apparatus which is an embodiment of the present invention, and FIG. 1(b) is a partially cutaway front view of the automatic electrode holder clamping device shown in FIG. Valley side sectional view of the static pressure fluid part, Figure 1(c)
is a partially cutaway bottom view of the electrode holder automatic clamping device shown in FIG.
3(a) and 3(b) are a sectional view of a magazine and a perspective view of an electrode holder applied to the automatic electrode exchange device of FIG. 2. FIG. In each of the above figures, 1 is a spindle head of an electrical discharge machining apparatus, and an electrode surface plate 2 is attached to this spindle head 1. 3 is a block having female dovetail shaped portions 4a, 4b, 4c, and 4dft fixed to the electrode surface plate 2; 5 is the female dovetail shape %fs of this block 3;
This electrode holder has a female dovetail shape that has a male and female dimensional matching relationship with a + 4 b.

Reference numeral 6 denotes a piece provided in the female dovetail portion 4b, and its tip part has the same dimensions as the wedge portion in the female dovetail portion 4b. Furthermore, the key 7 and the guide groove 8 guide the top 6 when it moves forward or backward. Reference numeral 9 denotes another block provided on the side surface of the block 3, and this block 9 has two pistons 10 arranged in parallel. Tip 11 of piston 1 ()
is separated and joined to the block 6, and the rear end 12 passes through the block 9, and the spring 1 is passed through the bottle 13 provided in the narrow diameter part.
4, so that the piston 10 is always engaged with the spring 1
It is pulled outward by an elastic force of 4.

A cylinder chamber 15 is led to another cylinder chamber 17 through a conduit 16. A piston 18 provided in the cylinder chamber 17 is constantly pressed by a disc spring 20 via a shaft 19. Another block 21 connected to the block 9 houses a shaft 19 and a disc spring 20, and houses a piston 22 in its upper part, which is engaged with the shaft 19 by a nut 23. When the piston 22 is pulled upward, the disk spring 20 is compressed, and the static pressure of the working fluid in the cylinder chamber 17 becomes zero. Conversely, when the piston 22 moves upward, the piston 18 is pressed by the disc spring 2 ( ), and the pressure inside the cylinder chamber 17 becomes high. 24 is the piston 22 and block 2
This is a cylinder chamber provided between 1 and 2. 25 is block 9
)e when carrying in the electrode holder 5 with a stopper fixed to
Perform positioning in the vJ direction. A hook 26 is provided on the lower end surface or side surface of the electrode holder 5 so that it can be carried out by engaging with the arm 50 shown in FIG. 27 is a conduit, one end of which is connected to the cylinder chamber 24, and the other end connected to the small diameter cylinder 28.
The small diameter cylinder 28 is connected to an oil path 29.

30 is a large-diameter cylinder installed coaxially and adjacent to the small-diameter cylinder 28, and the Rubiston 3, which is operated by air pressure, acts as a king.
1 is built-in. A piston rod 32 protrudes from the large diameter cylinder 30 to the small diameter cylinder 28 and penetrates through it. Air pressure is supplied to this large diameter cylinder 3° by a solenoid valve 33. When the solenoid valve 33 is not energized, air pressure is introduced into the cylinder chamber 30a, the piston 31 retreats,
Working fluid flows into the small diameter cylinder 28 from the oil bath 29 . Next, the solenoid valve 33 is energized, and the cylinder chamber 3()
When air pressure acts on b and the piston 31 moves forward, the working fluid in the small diameter cylinder 28 is pressurized by the piston 34 and guided to the block 21 (D'/') 7 da chamber 24 through the conduit 27. As a result, the piston 22 is lifted, the piston 18 becomes unloaded, the static pressure in the cylinder chamber 17 becomes zero, and the piston 10 is moved backward by the elastic force of the spring 14. Furthermore, when the solenoid valve 33 is not energized, the cylinder chamber 2
4, the static pressure becomes zero, and the piston 18 is pressed by the disk spring 20 via the shaft 19. Therefore, the cylinder chamber 15, 17 becomes high pressure, and the piston 10 moves forward to move the piece 6. Press.

Reference numeral 51 shown in FIG. 2 is a magazine for storing the holder 5, and as shown in FIG. 3, this magazine 51 is provided with a storage portion 52 having a female dovetail shape on its outer periphery. The number of electrode holders 5 stored in the magazine 51 is not particularly limited as long as the dimensional relationship between adjacent electrode holders 5 is acceptable, but in the case of this embodiment, an example in which four electrode holders 5 are provided for simplicity is shown. . Magazine 51 is connected to motor 531 rotational position detector 54. Based on the electrode number command from other mechanisms necessary for rotation, stopping, etc. and its control device (both not shown), the magazine 51 is automatically indexed to the electrode indexing position 51a and stopped.

Further, the magazine 51 is fixed to the main body of the electrical discharge machining apparatus by a support member 55 or the like. Reference numeral 56 denotes a cylinder, and the tip thereof is provided with an arm 50 that engages the hook 26 of the polarizing holder 5. This forward and backward movement of the cylinder 56 transports the electrode holder 5 on the magazine 51 to the electrode holder automatic clamping device at the lower end of the spindle head 1, or vice versa, moves the electrode holder 5 on the spindle head 1 into the magazine 5.
It has each function to store in 1. 57 is an intermediate guide when moving the electrode holder 5 from the storage part 52 of the macajin 51 to the block 3, and prevents the electrode holder 5 from falling during movement, and the female dovetail shaped part 4a of the block 3.
, 4b is provided so that insertion into the holder 4b can be performed smoothly.

Next, the operation of the automatic electrode exchange device in the electrical discharge machining apparatus of the present invention described above will be explained. First, spindle head 1
It is assumed that the electrode holder 5 does not exist in the automatic electrode holder clamping device and is waiting in an unclamped state. In addition, the phase constant electrode has already been indexed on the magazine 51 and set at the electric cylinder indexing position 51a, and the main shaft position has been returned to the position required for loading and unloading the electrode holder 5 in advance. shall be. Under such initial conditions, an automatic interchanging operation of the electrodes is performed. Now, the cylinder 56 moves forward, and the hooks of the electrode holder 5 are engaged with the arms 26 by the arm 50, and then the electrode holder 5 moves forward.
The intermediate guide 57 is guided and inserted into the block 3 of the automatic electrode holder clamping device. The inserted electrode holder 5 hits the stopper 25, and then the cylinder 5
6 continues to be pressed. Next, when the solenoid valve 33 becomes non-energized, the working fluid in the cylinder chamber 24 becomes non-pressurized, and the book spring 20 presses the piston 18 . Therefore, the static pressure in the cylinder chambers 15, 17 increases and the piston 10 moves forward to press the top 6.

By the way, the female dovetail shaped portions 4a, 4 of the block 3
Since the same-shaped wedge-shaped portion of the electrode holder 5 is already facing the electrode holder 5, the electrode holder 5 is pressed against the female dovetail-shaped portions 4a and 4b of the block 3, and a positioning clamp 11 is performed. First, the electrode holder 5 is moved by the cylinder 56.
Since the stopper 25 is positioned in the loading/unloading direction, the tm holder 5 is moved by the pressing action of the piston 10.
This means that positioning and clamping in the x, y, and z axis directions have been completed. If the TI valve 33 has such a non-excited clamping mechanism, even in the event of an unexpected accident such as a power outage, the X of the electrode can be fixed.

No misalignment occurs in the Y and Z axis directions. When the clamping is completed, the engagement between the arm 50 and the hook 26 is released, and the cylinder 56 is retracted. When the retraction of the cylinder 56 is completed, all electrode attachment operations are completed, and machining can begin. When machining is completed and the electrode is replaced with another one or stored in the magazine 51, the spindle head 1 first rises and returns to the electrode replacement position, then the cylinder 56 moves forward and the electromagnetic The valve 33 becomes energized, the piston 10 retreats, and the electrode holder 5 becomes unclamped. At the same time that arm 50 engages hook 26, cylinder 56 is retracted;
All the electrode holders 5 have been stored in the magazine 5]12-. By the way, if another electrode number is selected, the electrode installation and installation are performed sequentially in a manner similar to that described above. By the way, unless the machining tank of the electrical discharge machining apparatus has a particularly large area, when replacing the electrode, the lower end of the electrode 5811-t,
Since the processing unit 59 moves through the processing unit, it is necessary to have an appropriate dimensional relationship to avoid interference and collision between the two. However, since the direction in which the electrode holder 5 can be carried in and out of the block 3 is only possible by parallel movement from the lateral direction, it is possible to set the electrode exchange position of the main shaft at the upper limit of the main shaft stroke. This not only allows the main spindle stroke to be fully used as the entire machining stroke, but also allows the use of long electrodes. Furthermore, the electrode can be replaced with the electrode positioned close to the workpiece, and the overall height of the electrical discharge machining apparatus can be reduced.

As described above, according to the electrical discharge machining apparatus according to the present invention,
comprising an electrode holder having a female dovetail shape and a block having a female dovetail shape formed by male and female dimensional engagement metals, in a direction perpendicular to the loading/unloading direction of the electrode holder;
The entire electrode holder is clamped by a clamp piston operated by a static pressure fluid, the tip of the clamp piston constitutes a part of a wedge-shaped portion formed by the block, and the static pressure fluid is applied to the entire electrode holder. Since the electrode holder is equipped with an automatic clamping device that maintains the electrode holder in a pressurized state during clamping, the effective machining stroke of the ball shaft is You get enough.

■ The electrode holder has a female dovetail shape! It has high rigidity and allows the use of large electrodes.

■ Clamping using static pressure fluid increases the clamping force of the electrode holder, improving its positioning accuracy and causing almost no misalignment due to reaction forces during machining.

■ When using a non-excited clamp mechanism that uses static pressure fluid, the electrodes will not fall during a power outage, and
There is no need to clamp the electrode position again.

(2) Since the arm that transports the entire electrode holder moves only in the parallel direction, the transport mechanism is simplified and it can be manufactured at low cost, among other excellent effects.

[Brief explanation of the drawing]

FIG. 1(a) is a partially cutaway front view of an electrode holder automatic clamping device in an electric discharge machining apparatus which is an embodiment of the present invention, and FIG. 1(b) is an electrode holder automatic clamping device shown in FIG. 1(a). Each side sectional view of the device and its hydrostatic fluid section, Fig. 1 (
C) is a partially cutaway bottom view of the electrode holder automatic clamping device shown in FIG. 1(a), FIG. 3(a) and 3(b) are a sectional view of a magazine and a perspective view of an electrode holder applied to the automatic electrode exchange device of FIG. 2. In the figure, 1... ball shaft head, 2... electrode surface plate,
3', 9, 21--block, 4 a, 4 b
+ 4 c + 4 d...Female dovetail shape part,
5... Electrode holder, 6-... Top, 7... Key, 8
... Guide groove, 10.18, 22° 31.34 ... Piston, 11 ... Tip part, 12 ... Rear end part, 13.
...Pin, 14...Spring, 15.17.24, 30a
, 30b ++ cylinder chamber, 16.27... electric circuit, 19... shaft, 20... disc spring, 23...
Nut, 25...stopper, 26...hanging tool, 28
...Small diameter cylinder, 29...Oil bath, 30...
・Large diameter cylinder, 32...Piston rod, 33...
・Solenoid valve, 50... Arm, 51... Magazine, 5
1a... Electrode indexing position, 52... Storage section, 53
...Motor, 54...Rotational position detector, 5...Support, 56...Cylinder, 57...Intermediate guide. In addition, in the figures, "same" and "same" indicate the same or equivalent parts. Agent Masuo Oiwa Figure 1 (a) (b) 321 4 18 . 713 ・ ・ ・ , 7 / ■ 707 4 ・ ・ 12 ・ ′・″ 1115 17 25 ・z;;2 15 ;

Claims (5)

[Claims] (1) In an electric discharge machine equipped with an automatic electrode exchange device that uses an electrode holder as a whole medium and is transported between the spindle head and the magazine, the electrode holder automatic flanging device is attached to the spindle head side. is provided with a block having a female dovetail shape formed by male and female dimensionally engaged metals with the electrode holder having the female dovetail shape, and a wedge-shaped portion on one side of the block has the electrode holder having the female dovetail shape. At least one flanged piston metal is provided in a direction perpendicular to the loading/unloading direction and operated by static pressure fluid, and the tip of the clamp piston is connected to the wedge-shaped portion formed by the block having the female dovetail shape. while the static pressure fluid is clamping the electrode holder having an annular dovetail shape;
An electrical discharge machining device characterized in that it is configured to be maintained in a pressurized state. (2) The clamp piston has the female dovetail shape! 2. The electric discharge machining apparatus according to claim 1, wherein two electric discharge machining apparatuses are arranged in parallel on a block. (3) A clamping piece that is separated from and joined to the tip of the clamp piston is disposed at the tip of the clamp piston, and a part of the piece has a wedge-shaped portion formed by the block having the female dovetail shape. The electric discharge 71 [] device according to claim 1 or 2, which is characterized in that the following are all common features: (4) Pressurization of the static pressure fluid is performed by a separate piston provided in the electrode holder automatic clamping device and an elastic body that presses it, and unless a working fluid is supplied from the outside to release the piston. 4. The electric discharge machining apparatus according to claim 1, wherein the electrode holder can be clamped in the female dovetail shape under static pressure. (5) The release of the clamp piston has the female dovetail shape 1 at t+dI! 5. The electric discharge machining apparatus according to claim 1, wherein the electric discharge machining is performed by an elastic force of a spring or the like when the holder is in an unclamped state.