JP2894440B2 - Replacement device for welding electrode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding electrode exchanging apparatus mainly used for end plug welding of a nuclear fuel cladding tube.

[0002]

2. Description of the Related Art End plug welding of a cladding tube containing nuclear fuel involves the following steps.
It is performed in a welding chamber where a certain welding atmosphere is created by evacuation and gas replacement, but in this case it is difficult to replace the welding electrode while maintaining the welding atmosphere of the welding chamber due to the complexity of the gas seal etc. It is said that
Until now, the electrodes were replaced after the welding chamber was returned to atmospheric pressure.

[0003]

However, the conventional electrode replacement for destroying the welding atmosphere requires a vacuum
Gas replacement had to be performed anew, and operations other than electrode replacement occurred, and the fuel rod surface was sometimes contaminated with radioactive materials by destroying the welding atmosphere. Therefore, an object of the present invention is to make it possible to replace electrodes without destroying the welding atmosphere in arc welding that requires a certain welding atmosphere, such as end plug welding of a nuclear fuel cladding tube.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by providing an electrode exchange device capable of supplying, gripping and discharging electrodes without impairing the welding atmosphere of a welding chamber. This electrode exchange device shall have an airtight structure for operating in the same pressure environment as in the welding chamber,
It is roughly divided into four parts: an electrode supply mechanism, an electrode storage mechanism, an electrode chucking mechanism, and an electrode discharge mechanism.

[0005] The electrode supply mechanism is a part for taking in replacement electrodes from the outside.
A seal valve is provided at a location, and one
A rod-shaped welding electrode inserted one by one is airtightly received in the electrode passage by opening and closing the upper seal valve, and the welding electrode is opened and closed by the lower seal valve.
The air-lock is performed at the time of receiving and sending out the electrodes as a configuration in which the electrodes are air-tightly dropped from the lower opening of the electrode passage by closing. The electrode supply mechanism was provided with a gas inlet for applying gas pressure to the electrode passage, so that the inside of the mechanism was maintained at the same level of the welding atmosphere as the welding chamber for welding.

The electrode storage mechanism is a part that stocks the electrodes sent from the electrode supply mechanism and can take out the electrodes one by one each time the electrode is replaced. The electrode storage mechanism has a columnar rotor that rotates about a vertical axis. The rotor is provided with vertically penetrating electrode storage holes for storing one welding electrode at each of a plurality of locations on an arc concentric with the rotation axis thereof, thereby facilitating the attachment of the airtight seal. The electrode storage mechanism is connected airtightly so that an upper opening of the electrode storage hole faces a lower opening of the electrode passage, and the rotor intermittently rotates while the lower opening of the electrode storage hole is closed. The welding electrodes dropped from the electrode supply mechanism are sequentially received in the electrode storage holes, and when the lower opening of the electrode storage holes comes to the open position, the welding electrodes are dropped by their own weight one by one. The rotor has a gear formed on its outer periphery, and is intermittently rotated by a stepping motor via the gear.

The electrode chucking mechanism is a part for gripping the electrode sent from the electrode storage mechanism and exposing the tip of the electrode to the inside of the welding chamber. A chucking sleeve to which a collet for gripping the welding electrode is attached is slidably accommodated in a cylindrical housing having a tapered hole facing the collet, and an upper opening of the electrode hole is open. The upper end is hermetically connected to the lower end of the electrode storage mechanism and the lower end is hermetically inserted into the electrode insertion opening on the upper surface of the welding chamber so as to face the lower opening of the electrode storage hole at the position. The welding electrode in the electrode hole is gripped or released by an operation of vertically moving the chucking sleeve. Below the electrode insertion opening of the welding chamber, a stopper that regulates the tip position of the welding electrode gripped by the electrode chucking mechanism is provided so as to be able to protrude and retract. Also,
The above-mentioned chucking sleeve is provided with a piston-cylinder mechanism, and is operated to move up and down by air pressure.

The electrode discharging mechanism is a part for taking out the electrode released by the electrode chucking mechanism through the welding chamber, and has two hermetic seal valves at upper and lower portions in the middle of a vertical electrode passage, and an opening at the lower surface of the welding chamber. The welding electrodes that are attached to the electrode discharge holes and fall one by one into the upper opening of the electrode passage are air-tightly received in the electrode passage by opening and closing the upper seal valve, and the welding electrode is received. As in the above-described electrode supply mechanism, air lock is performed at the time of receiving and sending out the electrode, as a configuration in which the lower seal valve is opened and closed to drop its own weight from the lower opening of the electrode passage. The electrode discharge mechanism was provided with a gas inlet for applying gas pressure to the electrode passage, so that the inside of the mechanism was maintained at the same pressure as the welding chamber.

The electrode discharge port of the welding chamber is shifted laterally from the electrode insertion port so as to avoid a workpiece directly below the electrode insertion port, and an electrode chucking mechanism is provided between the electrode insertion port and the electrode discharge port. Is provided with a moving mechanism for moving the airtight. Further, in order to insert and remove the electrode chucking mechanism with respect to the welding chamber, an elevating mechanism for vertically moving the electrode chucking mechanism is provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention used for end plug welding of a nuclear fuel cladding tube will be described below with reference to FIGS. First, FIG. 1 is a longitudinal sectional view showing the overall configuration of the apparatus, FIG. 2 is a left front view of the essential parts of FIG. 1, FIG. 3 is an enlarged longitudinal sectional view of the essential parts of FIG. 1, and FIG. It is a top view. In FIG. 1, an electrode supply mechanism 1, an electrode storage mechanism 2, and an electrode chucking mechanism 3 are integrally connected in order from the top, and these are connected to a lifting mechanism 5 via a bracket 4. Here, the electrode supply mechanism 1 is configured such that two upper and lower seal valves 6 and 7 each composed of a ball valve and two pipes 8 and 9 are flange-connected with a gas seal (not shown) interposed therebetween. Vertical tubular electrode passage 10
Are formed.

Although the seal valves 6 and 7 are both open in the illustrated state, the spherical valves 6a and 7a are rotated by 90 degrees, and the center holes thereof are perpendicular to the electrode passages 10 as shown by broken lines, respectively. Close. Opening and closing operations of the seal valves 6 and 7 are performed by attached solenoids 6b and 7b in the case shown in the figure. Gas pressure inlets 8a and 9a for applying the same gas pressure as the welding atmosphere from a gas pressure source (not shown) are provided on the side surfaces of the pipes 8 and 9. The electrode supply mechanism 1 has a tubular body 9 fitted into a shallow circular concave portion on the upper surface of an upper support 11 fixed to the bracket 4 with screws, and the periphery thereof is fixed by welding.

On the other hand, as shown in FIG.
Is a cylindrical rotor 13 between an upper support 11 and a lower support 12 similarly screwed to the bracket 4.
Are supported so as to rotate about a vertical axis via two upper and lower bearings 14. Rotor 1
Reference numeral 3 has small diameter portions having the same diameter at the upper and lower ends, and a gear 15 is integrally formed therebetween. The small-diameter portion on the upper end side of the rotor 13 is rotatably fitted into a circular concave portion on the lower surface of the upper support 11, and an airtight seal 16 is inserted between the small-diameter portion of the rotor and the upper support 11. The small diameter portion on the lower end side of the rotor 13 is rotatably inserted through the through hole of the lower support 12 and protrudes downward.

A small diameter portion penetrates vertically through the rotor 13,
30 points on six arcs (see FIG. 4) concentric with the rotation axis.
An electrode storage hole 18 for storing one electrode 17 at a time pitch is provided. And the electrode storage hole 18
The upper opening is set so as to face the lower opening of the electrode passage 10 of the electrode supply mechanism 1. Here, from the lower part of the electrode passage 10 to the upper part of the electrode storage hole 18, the electrode 1 is formed in a funnel shape including the thin portion of the upper support 11 interposed therebetween, and the electrode 1 from the electrode passage 10 to the electrode storage hole 18 is formed.
The approach of 7 is being guided. The rotor 13 is driven by a stepping motor 19 shown in FIG. The stepping motor 19 is fixed to the overhang of the bracket 4 by screws adjacent to the rotor 13, and a gear 20 attached to the shaft end is engaged with the gear 15 of the rotor 13.

In FIG. 3, the electrode chucking mechanism 3
A chucking sleeve 26 with a collet 25 screwed to the tip inside a cylindrical housing consisting of a cylinder lid 21, a cylinder 22, a chucking holder 23, and a current-carrying chip 24 in order from the top is slidable in the axial direction. It is configured to be accommodated in. The chucking holder 23 has a tubular structure, and has a double structure in which a sleeve 27 made of a conductive material is fitted. The chucking sleeve 26 is slidably housed in a guide hole passing through the center of the sleeve 27. Have been. The cylinder 22 is a cylindrical body and forms a cylinder chamber 29 for accommodating a piston 28 integrally formed on the upper part of the chucking sleeve 26 by vertically fixing the cylinder lid 21 and the chucking holder 23 with screws. .

The cylinder lid 21 is a disc-shaped lid, which fits into the cylinder 22 via a boss projecting downward, and guides the upper end of the chucking sleeve 26 to the center.
a is provided. A circular concave portion is formed on the upper surface of the cylinder lid 21, and a small-diameter portion on the lower end side of the rotor 13 is rotatably fitted into this portion. An airtight seal 30 is inserted between the small rotor portion and the cylinder lid 21.
Here, the fitting position of the rotor 13 to the cylinder lid 21 is set such that the arc in which the electrode storage holes 18 are arranged overlaps the center of the guide hole 21a. A disk 31 made of a hard material is fixed to the bottom surface of the circular concave portion of the cylinder lid 21 in which the rotor small-diameter portion is fitted with a center screw 32 through a slight gap from the end surface of the rotor small-diameter portion. A small hole 31a for passing the electrode 17 is formed in the position 31 overlapping the guide hole 21a.

The current-carrying tip 24 is a cylindrical body made of a conductive material, and has a two-stage hole having a large-diameter hole for accommodating the collet 25 and a small-diameter hole for inserting the electrode 17 at the center thereof. A tapered surface corresponding to the tapered surface of the collet 25 is formed at the stepped portion of the two-stage hole facing. The current-carrying tip 24 has a small-diameter portion having a thread formed on the outer peripheral surface at the upper end, and the sleeve 27 is inserted through the small-diameter portion.
Into the screw hole at the tip of the chucking chuck 2
3 and is fixed. A screw is also formed on the outer peripheral surface of the lower end portion of the current-carrying tip 24, and a nozzle-shaped cap 3 having a screw formed on the inner peripheral surface is formed in this portion.
3 is screwed in, fixed against the tip end surface of the chucking holder 23.

At the center of the chucking sleeve 26, an electrode hole 34 into which the electrode 17 is inserted is formed therethrough. The upper half of the electrode hole 34 has a slightly larger diameter than the electrode 17, and the lower half of the electrode hole 34 in which the gripped electrode is housed is the electrode 17.
Being dense against. The upper end face of the cylinder lid 21 located in the guide hole 21 a is formed in a funnel shape for guiding the entry of the electrode 17. The collet 25 fixed to the distal end of the chucking sleeve 26 is cylindrical, and the electrode 17 is formed on the inner peripheral surface of the distal end portion that is flexibly formed by several slits cut in the axial direction from the distal end surface. A claw portion to be gripped is formed, and the above-described tapered surface is formed on the outer peripheral surface. The cylinder 22 surrounding the piston 28 integral with the chucking sleeve 26 has a piston 2
Air ports 22a and 22b for sending compressed air to the upper and lower cylinder chambers 29 of the cylinder 8 are provided.

A cable terminal 35 for connecting an electric cable (not shown) is attached to a side surface of the chucking holder 23, and a distal end thereof is electrically connected to the sleeve 27. The inside of the electrode chucking mechanism 4 having the above-described configuration is hermetically sealed in the axial direction, between the boss portion of the cylinder lid 21 and the cylinder 22, between the piston 28 and the cylinder 22,
Between the cylinder 22 and the upper end of the sleeve 27 fitted therein, the lower end of the sleeve 27 and the chucking holder 23
And the sleeve 27 and the chucking sleeve 26
And airtight seals 36 to 40 are inserted between them. In such an electrode chucking mechanism 3, a small-diameter constricted portion formed partially in the cylinder 22 is fitted and held from the front into a U-shaped notch of a horizontal portion formed L-shaped in the bracket 4. I have.

Returning to FIG. 1, the lifting mechanism 5 is composed of a vertical feed screw 42 rotated and driven by a servo motor 41 and a ball nut 43 meshing with the vertical feed screw 42. The servo motor 41 and the feed screw 42 are mounted on a bracket 44. Supported. The electrode supply mechanism 1, the electrode storage mechanism 2, and the electrode chucking mechanism 3, which are integrally connected up and down, have the bracket 4 fixed to the ball nut 43 with screws, and as a whole move up and down by the rotation of the feed screw 42.

Referring again to FIG. 3, the welding chamber 45 is a rectangular parallelepiped block, and a welding space 46 having a circular cross section is formed in the center along the longitudinal direction in a tunnel shape, and the welding space 46 is hermetically closed at both ends. A mounting seat for a flange (not shown) is formed. An electrode insertion opening 47 into which the lower end portion of the electrode chucking mechanism 3 is inserted as shown in the drawing is provided vertically from above in the welding chamber 45 toward the welding space 46. An electrode outlet 48 for dropping and discharging the later electrode 17 is provided vertically from below. Further, a window hole 49 for observing the welding condition is provided so as to penetrate the welding space 46 back and forth. The front and rear openings of the window hole 49 are hermetically closed by a transparent body.

In FIG. 3, the electrode chucking mechanism 3 is located at the welding position. However, if the electrode discharge port 48 is provided directly below the electrode chucking mechanism 3, the electrode 17 falls when the electrode 17 is replaced during the welding operation. Will hit the workpiece. Therefore, as shown in the plan view of the welding chamber 45 in FIG.
The electrode discharge port 48 is provided at a position shifted in the horizontal direction from the electrode insertion port 47, and a gap therebetween is cut out in an arc shape to communicate with each other. Then, in order to horizontally move the electrode chucking mechanism 3 between the welding position and the electrode discharge position, that is, between the electrode insertion port 47 and the electrode discharge port 48, as shown in FIG. A moving mechanism 50 is provided. The moving mechanism 50 is configured such that a swivel 51 is rotatably supported by a bearing 52, and the elevating mechanism 5 that supports the electrode chucking mechanism 3 is fixed to the upper surface of the swivel 51 via a bracket 44 by screws. . FIG. 6 shows a plan view of the swivel table 51.

As shown in FIG. 3, the swivel table 51 includes a bearing 52.
Are fastened by screws 54 to a back plate 53 fitted from the upper surface and fitted from the lower surface. The outer ring of the bearing 52 is fitted on the welding chamber 45 and is fixed by screws 56 via a bearing retainer 55. Electrode chucking mechanism 3 is inserted until the welding space 46 through the through-hole and the electrode insertion slot 47 of the swivel base 51 and the back plate 3. Between the chucking holder 23 and the back plate 53 is inserted hermetically seal 57, the airtight seal 58 is inserted between the back plate 5 3 and the welding chamber 45. In the case shown, the swivel table 51 is manually rotated by 40 degrees from the welding position in FIG. 6A to the electrode discharging position in FIG. 6B, whereby the electrode chucking mechanism 3 discharges the electrode from directly above the workpiece. Move to just above exit 48.

The used electrode 17 discharged from the electrode chucking mechanism 3 immediately above the electrode discharge port 48 is taken out to the outside through the electrode discharge port 48. In order to maintain airtightness at that time, FIG. As shown, an electrode discharge mechanism 59 is attached to the electrode discharge port 48 of the welding chamber 45. The electrode discharge mechanism 59 has the same meaning as the electrode supply mechanism 1, and includes two upper and lower seal valves 60 and 6 each composed of a ball valve.
An electrode passage 64 is formed by 1 and the two tubes 62 and 63. The tube 62 is inserted into the electrode outlet 48, and the periphery thereof is welded to be airtightly fixed to the welding chamber 45. Tubes 62 and 63 and seal valves 60 and 6
Reference numeral 1 denotes a flange connection with a gas seal (not shown) interposed therebetween. A gas pressure inlet 63 a for applying the same gas pressure as the welding atmosphere to the electrode passage 64 from a gas pressure source (not shown) is provided on the side surface of the tube 63.

On the other hand, in FIG. 3, in order to regulate the tip position of the electrode 17 newly gripped by the electrode chucking mechanism 3 to a fixed height, the electrode 1 is placed in the welding chamber 45.
A stopper 65 is provided which can be retracted from the position of the tip of the shutter 7. The stopper 65 is formed of a strip-shaped plate piece and horizontally turns around one end as a fulcrum, and receives the tip of the electrode 17 at the other end. FIG. 8 shows the turning mechanism.
It is sectional drawing which follows the II-VIII line. In FIG. 8, a turning shaft 66 is provided which passes through the welding chamber 45 from below and reaches the welding space 46, and the stopper 65 is fixed at one end to its upper end. An airtight seal 67 is inserted between the pivot 66 and the welding chamber 45. The turning shaft 66 is driven by a pneumatically operated rotary actuator 68 fixed to the welding chamber 45 with a screw (not shown), and protrudes and retracts between an electrode receiving position shown and a retracted position rotated 45 degrees from this position.

The description of the configuration of the apparatus has been completed above, and the operation thereof will be described next. During the welding operation, the welding chamber 45 is evacuated, and an inert gas such as helium is filled at a predetermined pressure to form a welding atmosphere. At the same time, the same gas pressure is applied to the gas pressure inlets 8a, 9a and 63a from a gas cylinder via an electromagnetic valve to maintain the pressure in the apparatus. Then, after stopping the gas pressure to the gas pressure inlet 8a, the upper seal valve 6 of the electrode supply mechanism 1 is opened,
One electrode 17 is inserted from the upper end opening of the electrode passage 10 and housed between the seal valve 6 and the seal valve 7. Next, the seal valve 6 is closed, the gas pressure is again applied to the gas pressure inlet 8a, and then the lower seal valve 7 is opened.

When the lower seal valve 7 is opened, the electrode 17 falls into the electrode storage hole 18 of the electrode storage mechanism 2. Therefore, the lower seal valve 7 is closed, and the rotor 13 is rotated by one step (in this case, six rotors are stored at a pitch of 30 degrees).
As a result, the next electrode storage hole 18 faces the electrode supply mechanism 1, and the electrode 17 stored in the electrode storage hole 18 during that time.
Moves on a disk 31 closing the lower opening of the electrode storage hole 18. When such an operation is repeated six times and the electrodes 17 are loaded in all the electrode storage holes 18, air pressure is applied to the lower surface of the piston 28 via the lower air port 22 b of the electrode chucking mechanism 3, and the chucking sleeve 26 is moved. lift. Thereby, the claw portion of the collet 25 is opened by elasticity. Then, when the rotor 13 is rotated by one step, the leading electrode 17 is turned into the small hole 31a of the disc 31.
And falls into the electrode hole 34 of the chucking sleeve 26 via the guide hole 21a of the cylinder lid 21. The tip of the electrode 17 passes through the collet 25 and the stopper 65
And stop.

Then, air pressure is applied to the upper surface of the piston 28 through the upper air port 22a, and the chucking sleeve 26 is pushed down. As a result, the tapered surface of the collet 25 is pressed against the tapered surface of the current-carrying tip 24, and the claws are closed to grip the electrode 17. The electrode 17 is now
Is completed, the stopper 65 is turned to the retracted position, and the workpiece is set in a predetermined relationship with the electrode 17. Here, FIG. 3 simply shows the to-be-welded body 70 in the present case by a chain line. The to-be-welded object 70 is a cladding tube 71 of nuclear fuel and its end plug 72. A plurality of nuclear fuel chips 73 are housed in the cladding tube 71 formed of a bottomed cylinder in an overlapping manner. It is fitted. The to-be-welded body 70 is positioned such that the butted portion P of the cladding tube 71 and the flange of the end plug 72 faces the tip of the electrode 17, and the entire periphery is welded. The current path during welding is based on the cable terminal 35.
→ The sleeve 27 → the conductive tip 24 → the collet 25 → the electrode 17 are formed in this order.

When replacing the electrode 17, the swivel 51 is swiveled to position the electrode chucking mechanism 3 immediately above the electrode outlet 48. Next, the air pressure is applied to the air port 22b to lift the chucking sleeve 26, open the collet 25, and discharge the electrode 17. When the electrode 17 falls into the electrode passage 64 of the electrode discharge mechanism 59, the upper seal valve 60 is opened, and the electrode 17 is moved to the upper and lower seal valves 60,
Housed between 61. Therefore, the upper seal valve 60 is closed and the gas pressure to the gas pressure inlet 63a is closed, and then the lower seal valve 61 is opened to drop the electrode 17 to the outside of the welding chamber 45. Thereafter, the lower seal valve 61 is closed, and the gas pressure is again applied to the gas pressure inlet 63a. Subsequent gripping of a new electrode 17 or replenishment of the electrode 17 into the rotor 13 is performed by repeating the procedure described above.

[0029]

As described above, according to the welding electrode replacement apparatus of the present invention, the taking-in of the electrode into the apparatus, the transfer / grasping inside the apparatus, and the discharge outside the apparatus are made airtight to the welding chamber. Since the welding can be performed while maintaining, the welding atmosphere in the welding chamber is not destroyed for the electrode replacement, the welding operation efficiency is improved, and the problem of contamination of the welded object due to the electrode replacement can be avoided. .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a welding electrode replacement device according to an embodiment of the present invention.

FIG. 2 is a left front view of FIG.

FIG. 3 is an enlarged view of a main part of FIG. 1;

FIG. 4 is a plan view of the rotor in FIG. 3;

FIG. 5 is a plan view of the welding chamber in FIG. 3;

FIGS. 6A and 6B are plan views of the swivel table in FIG. 3, wherein FIG. 6A shows a welding position and FIG.

FIG. 7 is a longitudinal sectional view showing an electrode discharging mechanism.

FIG. 8 is a sectional view taken along line VIII-VIII in FIG.

[Explanation of symbols]

 Reference Signs List 1 electrode supply mechanism 2 electrode storage mechanism 3 electrode chucking mechanism 5 lifting mechanism 6 seal valve 7 seal valve 10 electrode passage 13 rotor 17 electrode 18 electrode storage hole 24 conducting chip 25 collet 26 chucking sleeve 27 sleeve 28 piston 45 welding chamber 47 electrode Insertion port 48 Electrode discharge port 50 Swivel mechanism 59 Electrode discharge mechanism 60 Seal valve 61 Seal valve 65 Stopper

Continuing from the front page (72) Inventor Kiyoshi Mori 1-36-26 Yokosuka-shi, Kanagawa Prefecture Inside Apollo Precision Co., Ltd. (72) Inventor Morikatsu Kawamura 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki Prefecture Power reactor and nuclear fuel Within the Tokai Works of the Development Corporation (72) Inventor Shizuki Azura 4th Muramatsu, Oji, Tokai-mura, Naka-gun, Ibaraki Prefecture Within the Tokai Works of the Power Reactor and Nuclear Fuel Development Corporation (72) Inventor Yasunori Nemoto Tokai, Naka-gun, Ibaraki Prefecture No. 4 Muramatsu, Muradai 33 Power Reactor and Nuclear Fuel Development Corporation Tokai Works, affiliated to Nuclear Technology Co., Ltd. (56) References JP-A-63-2573 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B23K 9/29 B23K 9/00 501 B23K 9/16 B23K 9/26 B23K 9/12 331 B23K 9/133

Claims (8)

(57) [Claims] 1. A seal valve is provided at two upper and lower positions in the middle of a vertical tubular electrode passage, and a rod-shaped welding electrode inserted one by one from an upper opening of the electrode passage is opened and closed by the upper seal valve. And an electrode supply mechanism for airtightly receiving the welding electrode into the electrode passage and dropping the welding electrode from the lower opening of the electrode passage in an airtight manner by opening and closing the lower seal valve, and rotating about a vertical axis. It has a columnar rotor, and the rotor is provided with vertically penetrating electrode storage holes for storing the welding electrodes one by one at a plurality of locations on an arc concentric with the rotation axis thereof, and an upper opening of the electrode storage hole. Are airtightly connected to the electrode supply mechanism so as to face the lower opening of the electrode passage, and the rotor intermittently rotates while the lower opening of the electrode storage hole is closed and drops from the electrode supply mechanism. An electrode storage mechanism for sequentially receiving the welding electrodes into the electrode storage holes and dropping the welding electrodes one by one when the lower opening of the electrode storage holes comes to an open position; and inserting the welding electrodes at the center. A chucking sleeve having a collet for gripping the welding electrode at its tip is housed in a cylindrical housing having a tapered hole facing the collet so as to be slidable in the axial direction, The upper end is air-tightly connected to the lower end of the electrode storage mechanism so that the upper opening of the electrode hole faces the lower opening of the electrode storage hole in the open position, and the lower end is formed on the upper surface of the welding chamber. An electrode chucking mechanism that is hermetically inserted into an electrode insertion opening, and grips or releases the welding electrode in the electrode hole by a vertically moving operation of the chucking sleeve. An exchange device for a welding electrode, which is provided. 2. An airtight seal valve is provided at two upper and lower positions in the middle of a vertical tubular electrode passage, and is attached to an electrode discharge hole opened on the lower surface of the welding chamber. Each of the welding electrodes that drop at a time is airtightly received into the electrode passage by opening and closing the upper seal valve, and the welding electrode is self-weighted from the lower opening of the electrode passage by opening and closing the lower seal valve. 2. The welding electrode replacement device according to claim 1, further comprising an electrode discharging mechanism for dropping the welding electrode. 3. A stopper for restricting a tip position of a welding electrode gripped by an electrode chucking mechanism is provided below the electrode insertion opening of the welding chamber so as to be able to protrude and retract. An exchange device for a welding electrode as described in the above. 4. The welding electrode according to claim 2, further comprising a moving mechanism for airtightly moving the electrode chucking mechanism between the electrode insertion port and the electrode discharge port of the welding chamber. Exchange equipment. 5. A gas pressure inlet for applying gas pressure to an electrode passage of an electrode supply mechanism.
A replacement mechanism for a welding electrode according to claim 4. 6. A gas pressure inlet for applying a gas pressure to an electrode passage of an electrode discharge mechanism.
An apparatus for replacing a welding electrode according to claim 5. 7. The welding electrode changing device according to claim 1, further comprising a piston / cylinder mechanism for vertically moving a chucking sleeve of the electrode chucking mechanism by air pressure. . 8. The welding electrode replacement device according to claim 1, further comprising an elevating mechanism for moving the electrode chucking mechanism up and down.