JP2000296420A - Electric discharge machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the removal of cut off-pieces when a long workpiece to be cut, installed in a narrow part, is cut by underwater remote control, and efficiently remove chips during the cutting operation. SOLUTION: A pair of right and left clamp mounting plates 2, 3 are installed to a vertical body frame 1, and a clamping mechanism for fixing a workpiece to be cut is installed to the clamp mounting plates 2, 3. The clamping mechanism consists of a clamp receiving piece 6 and clamp pressing cylinders 10. Further, a servo driving part 5 having a servomotor 30 is installed to the body frame 1 through a working head 4. An electrode 20 is rotatably installed to the working head 4 through an electrode holder. The electrode holder is rotated by a first gear which can rotate by receiving the rotation of a gear 28 mounted to the rotary shaft of the servo-motor 30. Besides, a chip suction pipe 8 is erected from a base installed to the lower end part of the body frame 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machine for remotely cutting a workpiece to be cut, for example, a pipe, which is installed and fixed in water.

[0002]

2. Description of the Related Art For example, an in-core monitor housing installed in a lower mirror of a reactor pressure vessel of a nuclear power plant may be cut underwater. The in-core monitor housing is installed and fixed in a narrow part with long piping.

[0003] There is no commercially available apparatus that can cut a long pipe installed and fixed at an arbitrary position in water by remote control. In particular, it is difficult to perform cutting at a position immediately adjacent to the mounting portion of the long pipe installed on the lower mirror, that is, at a position that is the same as the upper surface of the lower mirror. Therefore, conventionally, complicated and expensive special machining equipment and the like have to be manufactured and depended on it.

[0004]

The special machining apparatus has a problem such as rigidity and has a problem of increasing the size. It is difficult to apply it to the processing in the narrow part of the installed long piping,
In addition, there is a problem that the cutting operation cannot be easily performed due to various constraint conditions (whether the replacement is all replacement or partial replacement, installation accuracy, installation state, installation environment, and the like). In particular, there are many restrictions on repairing pipes installed in nuclear reactor facilities, the cost of replacement work is high, and there is a problem that processing in narrow parts is a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and applies electric discharge machining to the cutting of a long pipe in a narrow portion to reduce the size of the apparatus and to remotely cut the pipe at various angles. Response and positioning of equipment, removal after cutting,
An object of the present invention is to provide a cutting electric discharge machine capable of performing efficient removal and collection of processing waste during processing, and also applicable to cutting of a pipe of a power generating nuclear reactor and the like, which can be remotely operated in water. .

[0006]

According to the present invention, there is provided a vertical body frame to which a pair of right and left clamp mounting plates are mounted, and a pair of a pair of right and left clamp mounting plates for mounting and fixing a workpiece to be cut. A clamping mechanism, a servo drive unit attached to the main body frame, a processing head fixed to the servo drive unit and attached to the main body frame,
An electrode holder rotatably mounted on this processing head,
An electrode attached to the electrode holder, a gear attached to a rotation shaft of the electrode holder to which rotation is transmitted by a gear attached to a rotation shaft of the servo drive unit, and the workpiece to be cut by the electrode. And a cutting suction mechanism for collecting chips generated at that time.

The invention corresponding to claim 2 is characterized in that a level adjusting screw is provided on a leg of the main body frame. The invention corresponding to claim 3 is characterized in that the machining head is provided with an angle adjusting mechanism capable of adjusting an angle corresponding to an angle of the workpiece to be cut.

According to a fourth aspect of the present invention, the clamp mechanism is provided with upper and lower receivers provided above and below the clamp mounting plate for fixing the workpiece to be cut, and a pressing cylinder provided corresponding to the receiver. And characterized by the following.

[0009] The invention corresponding to claim 5 is characterized in that the gears mounted on the rotating shafts of the servo drive unit and the electrode holder are each composed of no backlash gears. The invention according to claim 6 is characterized in that the electrode is formed in a triangular cross-sectional shape in which the contact surface side of the workpiece is thick and the opposite surface side is thin.

In the present invention, the cutting angle is determined by adjusting and setting the processing head, that is, the long pipe, to the processing head and the leg of the main body frame at an arbitrary cutting angle position. Then, the electric discharge machine is positioned at an arbitrary cutting position, the cylinder of the clamp mechanism is driven, and the pipe is pressed against the receiver to be fixed.
The suction device for collecting the processing waste is activated to start the cutting process.

According to the first aspect of the present invention, only the suction of the workpiece attached to the frame is operated until the electrode penetrates into the inside of the pipe, and the suction of the pipe side is also operated when the electrode penetrates, so that any cutting process can be performed. Can be performed efficiently.

The cutting and suction mechanism can improve the processing efficiency by sucking and collecting the processing chips generated during the cutting processing and maintaining the purity (electric conductivity) of the processing liquid. The suction and collection inside the pipe prevents the purity of the processing liquid in the pipe from decreasing, and collects all the processing waste.

According to the second aspect of the present invention, the angle and the level of the cutting section are adjusted by adjusting the level adjusting screw of the mounting section of the processing head to the frame of the processing apparatus main body and the leg section of the frame as the pipe cutting conditions. By adjusting the rotation angle of the electrode and the rotation axis of the electrode at right angles, it is possible to cut and flatten the pipe immediately near the mounting portion of the installed pipe.

According to the third aspect of the present invention, the angle of the frame mounting portion of the processing head can be adjusted to an arbitrary angle according to the situation of the cutting portion. According to the fourth aspect of the present invention, the clamping mechanism has a receiving cylinder and a pressing cylinder on the upper / lower portions of the processing head, and the cutting pipe is pressed against the receiving cylinder and fixed. Acts as a guide when the device is inserted. Further, the processing head is positioned and fixed at the cutting processing position, and after the cutting processing, can be removed while holding the pipe. Further, the clamp mechanism can be mounted regardless of the length of the pipe, and can be mounted even when the pipe is in a bare pipe state or already installed.

According to the fifth aspect of the invention, the rotation of the electrode is
The rotation of the servo drive mechanism is performed via gears. By providing a no-backlash gear on the gear, rotation control with good responsiveness to servo control can be performed. According to the invention of claim 6, it is possible to perform stable processing of the shape of the electrode with good processing efficiency. For this purpose, the pipe cutting portion is formed to have a triangular cross-sectional shape in which the contact surface side is thickened and the opposite surface side is thinned.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electric discharge machine according to the present invention will be described with reference to FIGS. 1 is a perspective view showing the entire electric discharge machine according to the present embodiment, FIG. 2 is a side view in FIG. 1, FIG. 3 is a front view in FIG. 1, and FIG. FIG. 4 (b) is a longitudinal sectional view showing the electrode of FIG. 4 (a).

1 to 3, reference numeral 1 denotes a main body frame, a pair of right and left clamp mounting plates 2 and 3 are mounted on one surface of the main body frame 1, and one end of a processing head 4 is mounted on the other surface of the main body frame 1. Part is attached, and this processing head 4
Is provided with a servo drive unit 5 at the other end. The servo drive unit 5 has a servo motor 30.

A pair of upper and lower clamp receivers 6 are mounted inside the right clamp mounting plate 2.
A chip suction pipe 8 is provided outside the right clamp mounting plate 2 from a base 7 attached to a lower end of the main body frame 1, and a suction hose 9 is attached to the chip suction pipe 8.

A clamp pressing cylinder 10 is provided outside the left clamp mounting plate 3 at a position corresponding to the clamp receiver 6, and a clamp 11 projecting forward and backward from the clamp pressing cylinder 10 passes through the left clamp mounting plate 3. For example, the outer surface of the workpiece 12 of a long pipe is pressed and fixed to the clamp receiver 6.

An air hose 13 is provided for the clamp pressing cylinder 10.
Is connected, and the other end of the air hose 13 is connected to a plug 15 of the control / power cable 14. The plug 15 is mounted on a mounting plate 16 fixed to the main body frame 1.

At the upper end of the workpiece 12, a suction adapter 17 is provided.
Is attached, and a suction hose 18 is attached to the suction adapter 17. An electrode 20 is arranged near the welding attachment portion 19 at the lower end of the workpiece 12. The electrode 20 is mounted on an electrode holder 21, a first rotating shaft 22 is mounted on the electrode holder 21, and an upper portion of the first rotating shaft 22 is rotatably mounted on the processing head 4 via a first bearing 23. Can be

A first gear 24 is mounted on a side surface of the first rotating shaft 22, and the first gear 24 meshes with a second gear 25, and the second gear 25 has a second rotating shaft 26. The second rotary shaft 26 is rotatably mounted on the processing head 4 via the second bearing 27.

The second gear 25 meshes with a third gear 28, and the third gear 28 is attached to a motor rotation shaft 29, and the motor rotation shaft 29 is a rotation shaft of a servo motor 30 of the servo drive unit 5. . Level adjusting screws 31 are attached to the lower end surfaces of the main body frame 1 and the clamp attachment plates 2 and 3, and a suspension wire 32 is provided on the upper attachment plate 16. Reference numeral 33 denotes a power cable.

In the apparatus having the above structure, the processing apparatus is self-standing on the main body frame 1 and has a level adjusting screw 31 on the leg, so that it can be adjusted according to the floor surface. The main frame 1 and the electrode 20 are connected to a third gear 28 by a servo drive motor 30.
And the apparatus is positioned and fixed to the pipe 12 and the processing head 4 for cutting the pipe 12 to be cut.

A clamp receiver 6 of a clamp mechanism for recovering the pipe 12 while holding it after cutting, a pneumatically-driven clamp pressing cylinder 10, and a suction mechanism for recovering processing chips generated during processing from the cut section. It comprises a chip suction pipe 8, a suction hose 9, a hanging wire 32 of the apparatus main body, and a control cable 14 for remote control.

FIG. 2 shows a reactor pressure vessel (RP) shown in FIG.
V) The processing head 4 and the body frame so as to diagonally cut the pipes installed on the slopes such as the in-core monitor housings (ICM housings) 35 and 36 installed on the lower mirror 34 at an angle and immediately near the slopes. The level adjustment screws 31 of the legs 1, 2, 3 are adjusted and set.

In order to adjust the angle and the like, as shown in FIG. 4, the angle attached to the main body frame 1 and the level adjusting screw 31 of the frame 1 are adjusted so that the electrode 20 of the processing head 4 can be positioned at the processing portion. . The rotation of the electrode 20 is controlled by a servomotor.
The rotation of the electrode 30 through the no backlash gear of the third gear 28 and the rotation of the electrode 20 from the second gear 25 through the no backlash gear of the first gear 24 eliminates the transmission loss of servo control. Fine processing control is possible.

In order to make the cut surface flat,
The mounting adjustment is performed so that the rotation surface of the electrode 20 is orthogonal to the rotation axis. When positioning the electrode 20, the workpiece 12,
In other words, the processing positioning is performed while paying attention to the level of the welding attachment portion 19 of the long pipe. The processing device integrates the power cable 33, the air hose 13, and the like into the control cable 14, routes the control device to the control device, and operates it by remote control.

FIG. 3 shows a detailed front view of the processing head 4 attached to the pipe 12 of the ICM housing 35 to be cut. The positioning of the electrode 20 of the processing head 4 is performed by moving the pipe 12 between the receptacle 6 of the clamp mechanism and the clamp pressing cylinder 10.
The guide is suspended at the cutting position while being guided, and when the positioning is completed, the cylinder 10 is operated and clamped.

The chip suction pipe 8 for sucking and collecting the processing chip is
It rises from the cutting portion of the main body frame 1 and is connected to a suction device via a suction hose 9. During processing,
The suction device is also operated, and the chips are collected by the filter. In addition, when the electrode 20 penetrates inside during processing, the suction hose 18 attached to the cutting pipe 12 via the suction adapter 17 also starts suction to increase chip recovery and processing efficiency.

FIG. 4 shows the electrode 20 at the cutting position of the pipe mounting portion.
FIG. The electrode 20 is mounted so that the rotation axis of the electrode holder 21 and the rotation surface of the electrode 20 are orthogonal to each other (to make the cut surface flat). The electrode 20 has a triangular cross-sectional shape as shown in FIG. 4B so as to enhance the processing efficiency by promoting the discharge of chips during processing and preventing side arcs.

FIG. 5 shows a reactor pressure vessel (RP) shown in FIG.
V) A device mounting layout for diagonally cutting pipes installed on a slope such as the ICM housings 35 and 36 installed on the lower mirror 34 at an angle and flat near the slope is shown. I
A CRD housing 37 is installed around the CM housing 12, and the processing apparatus has a structure that can be installed in a narrow portion.

The cutting apparatus has a shape which is installed along an ICM housing as the workpiece 12 and has an electrode 20.
Is used to transmit the rotation of the servo drive unit 5 via gears 24, 25, and 28 to utilize the space.

FIG. 6 shows a lower pressure vessel 34 of a reactor pressure vessel (RPV).
RPV lower mirror 34 of ICM housing 35 installed in
In a part of the working example of the repair processing of the pipe defect of the welding part with
An example of the cutting process of the ICM housing 36 in which the pipe defect is cut obliquely along the surface on which the pipe defect is installed and flat near the slope is shown.

FIG. 6A shows a reactor pressure vessel (RPV).
ICM housing 35 before cutting installed in lower mirror 34
FIG. 6B shows a state where the cutting has been completed and the upper ICM housing 36 has been removed. The head 4 of the cutting device is fixed at the cutting position of the ICM housing pipe 35.
The processing position is about 3800 from the ICM housing flange 37.
At the mm position, the ICM housing to be machined is a SUS material having an outer diameter of about φ50 mm and an inner diameter of about φ38 mm.

[0036]

According to the present invention, a workpiece to be cut can be clamped and fixed at an arbitrary cutting position by remote control, and a cut piece can be grasped and recovered after cutting. As a device for cutting a workpiece to be cut which is installed in a narrow portion, it is possible to flatly cut a portion immediately near the mounting portion.

Further, it is possible to perform a cutting process in a state in which a workpiece to be cut is previously attached (clamp-fixed) to a cutting device, and a pipe can be cut at an arbitrary cutting angle. Furthermore, by attaching a connection adapter to the suction pipe and the cutting pipe of the cutting apparatus and sucking the processing waste, the processing efficiency can be increased and clean processing can be performed.

Further, the processing accuracy and processing time are stable and can be fully utilized as a general-purpose processing apparatus. By replacing the processing head, the pipe connection adapter, and the clamp section, it is possible to increase the size of the pipe which can be processed and to increase the electrode size. By making the shape triangular, processing efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an electric discharge machine according to the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a front view in FIG. 1;

4A is an enlarged perspective view showing the vicinity of a workpiece and an electrode in FIG. 1, and FIG. 4B is a longitudinal sectional view of the electrode shown in FIG.

FIG. 5 is a bottom view for explaining an example of use of the electric discharge machine according to the present invention.

6 (a) is a side view partially showing a state before cutting in FIG. 5, and FIG. 6 (b) is a side view partially showing a state after cutting from the state of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Body frame, 2, 3 ... Clamp mounting plate, 4 ... Processing head, 5 ... Servo drive part, 6 ... Clamp receiver, 7
... Base, 8: Chip suction pipe, 9 ... Suction hose, 10 ... Clamp press cylinder, 11 ... Clamp, 12 ... Work piece, 13
... air hose, 14 ... control / power cable, 15 ... plug,
16… Top mounting plate, 17… Suction adapter, 18… Suction hose,
19 ... welding attachment part, 20 ... electrode, 21 ... electrode holder, 22 ... first rotating shaft, 23 ... first bearing, 24 ... first gear,
25 ... second gear, 26 ... second rotating shaft, 27 ... second bearing, 28 ... third gear, 29 ... motor rotating shaft, 30 ... servo motor, 31 ... level adjusting screw, 32 ... hanging wire , 33: Power cable, 34: Mirror under the reactor pressure vessel, 35: IC before cutting
M housing, 36 ... ICM housing after cutting, 37 ... Flange.

Claims (6)

[Claims] 1. A vertical body frame to which a pair of left and right clamp mounting plates are mounted, a pair of clamp mechanisms provided on the clamp mounting plate for mounting and fixing a workpiece to be cut, and a servo drive mounted to the main body frame. Part, a machining head that fixes the servo drive unit and is attached to the main body frame, an electrode holder that is rotatably attached to the machining head, an electrode that is attached to the electrode holder, and a rotating shaft of the servo drive unit. A gear attached to a rotating shaft of the electrode holder to which rotation is transmitted by the attached gear; and a cutting suction mechanism for collecting chips generated when the workpiece is cut by the electrode. Electrical discharge machining equipment. 2. The electric discharge machine according to claim 1, wherein a level adjusting screw is provided on a leg of the main body frame. 3. An electric discharge machining apparatus according to claim 1, wherein said machining head is provided with an angle adjusting mechanism capable of adjusting an angle corresponding to an angle of said workpiece to be cut. 4. The clamp mechanism comprises a receiving member provided above and below the clamp mounting plate for fixing the workpiece to be cut, and a pressing cylinder provided corresponding to the receiving member. The electric discharge machining device according to claim 1. 5. The electric discharge machining apparatus according to claim 1, wherein the gears mounted on the rotation shafts of the servo drive unit and the electrode holder are each a no-backlash gear. 6. The electric discharge machining apparatus according to claim 1, wherein the electrode is formed in a triangular cross-sectional shape in which a contact surface side of the workpiece is thick and an opposite surface is thin.