JPS6016313B2 - Automatic seal welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides seal welding between a tube and a tube plate that fixes the tube, or between the tube and a plug packed into the tube, or seal welding when attaching a plug to a ceiling with many holes. The present invention relates to a remote control type automatic welding device in which the device is suspended from the material to be welded by using a hole or tube hole in the tube plate or ceiling of the material to be welded.

In particular, it is useful for seal welding of a plug to a pongee pipe of a steam generator of a nuclear reactor where access to the material to be welded is restricted. The steam generator of the pressurized water reactor described above is a type of heat exchanger that exchanges heat with the primary water (pressurized water) heated in the reactor and vaporizes the secondary water. As shown in the figure, primary water flows from a hemispherical water body 2 at the bottom of a cylindrical shell 1 partitioned by a tube plate 3 and a partition wall 5 into a U-shaped subdivision group 4 firmly fixed to the tube plate 3. It is made up of structures. If a pinhole occurs in the thin tube (tube) 4 of this steam generator, a plug may be applied to block the tube to prevent primary water from leaking. There are various plug methods, but welded plugs are widely used because of their high reliability. However, this construction must be carried out under radiation. Therefore, in order to reduce radiation exposure, an automatic seal welding device that can perform remote welding has been desired. However, to date, no welding device reliable enough to be put to practical use has been developed.

The main reason for this is that there is no suitable guide device for guiding the welding torch under the tube with high precision, and furthermore, the welding tool is required to be extremely lightweight and 4-shaped.
The present invention has been developed in response to the above-mentioned needs, and is applicable not only to the general seal welding of tube sheets and pipes, but also to the pongee pipe opening of the ceiling tube sheet of the water chamber of a steam generator incorporated in a nuclear power generator. An object of the present invention is to provide a seal welding device that can automatically perform seal welding of a plug packed in a container.

The configuration of the present invention to achieve such an object is to move a plurality of tap shafts that are inserted into a hole in a ceiling, which is one of the materials to be welded, and then expand and tightly fit into the hole, in parallel and perpendicular directions to the ceiling. A walking robot moves in a hanging state along the ceiling by alternately translating the tap axis and entering the next hole, and a sardine attached to the walking robot approaches and leaves the hole. Possible attachments and
an attachment holder that is removably attached to the attachment; a tool stand that is attached to the attachment holder; and a plurality of parallel parts that hold a welding torch and cause the welding torch to draw a circle of approximately the same shape as the hole. a torch support plate that is provided on the tool stand via a ring; and a drive motor that moves the attachment towards and away from the hole to control the arc length of the welding torch that rotates around the hole. Features.

The configuration of the present invention will be explained in detail below based on a specific example shown in the drawings. In this example, seal welding is performed when a plug is packed into a thin tube of a steam generator installed in a pressurized water reactor. A walking robot 11 that moves downward along the tube plate 3 by using a so-called tube hole 10 in a pongee tube 4 fixed to a ceiling tube plate 3 is already known from Patent Publication No. 17121/1983. has been done. Although the yield walking robot 11 is not shown in detail in the drawings of the present application, the robot 11 expands in the vertical direction after being inserted into the tube hole 10', and moves the tap shaft that comes into close contact with the thin tube 4 vertically and horizontally within the machine frame. The tap shafts and the carriers are moved together so that the tap shafts are alternately removed and the next tube hole is inserted. It is installed so that it can be moved along the tube plate like a beetle. This walking robot 11
has arms 12 at both ends that can pivot 180 degrees.
The center of rotation of the arm 12 is located at a distance equal to an integral multiple of the pitch of the pongee tube from the above-mentioned walking tap axis. and,
An attachment 21 having a lifting function is located at a tip portion further away from the center of rotation by 5 pitches or an integral multiple of 5 pitches.
An attachment holder 127 to which a tool stand 13 is attached is removably attached to the attachment 21. The attachment 21 is shown in FIGS. 4a and 4b.
, c, the rotation arm 1 in place of the motor case
The bearing holder 23 housed in the bearing holder 2 and the joint tube 24 fitted to the attachment holder 127 are iron-coupled so that they move in the ball direction but do not rotate, and then the pole screw 3 is inserted.
3 and the ball nut 31, thereby connecting the joint cylinder 24.
The joint cylinder 24 is provided with a joint ball 26 that protrudes and retracts in a vertical direction at the lower end of the joint cylinder 24, so that it can be freely attached to and removed from the attachment holder 127. That is, a cylindrical bearing holder 23 is fixed to the rotating arm 12 of the walking robot 11 with its axis parallel to the axis of the tube hole 10.
A cylindrical joint tube 24 having a ball nut 31 fixed to the lower end thereof is coaxially connected to the tube 3 so as to be slidable in the direction of the ball. At the lower end of the bearing holder 23, a guide groove 2 for a dog 25 protruding inwardly from the joint tube 24 is formed on its circumferential surface.
5a is provided in the ball direction and serves as a slide guide for the joint cylinder 24, and the joint cylinder 24 cannot rotate relative to the bearing holder 23 due to the iron engagement between the dog 25 and the guide groove 25a. A ball screw 33 having a skew gear (worm wheel) 32 fixed to its upper end is rotatably provided on the inner periphery of the bearing holder 23, and the ball screw 33 meshes with the ball nut 31. The swing arm 12 is provided with a drive motor 35 for raising and lowering the attachment 21, and a worm 34 that meshes with the worm wheel 32 is attached to the output ball of the drive motor 35. In other words, when the drive motor 35 is driven, the ball screw 3 passes through the worm 34 and the worm wheel 32.
3 rotates, and by the rotation of the ball screw 33, the joint tube 24 to which the ball nut 31 is fixed moves along the guide groove 25a. A fixing groove 28 and a detachment groove 29 are provided at the lower end of the joint tube 24 , and a joint ball 26 is provided between the fixing groove 28 and the detachment groove 29 so as to be movable. It is held by a fixed holder 27 that is biased downward by the spring 3. Normally, the fixed holder 27 is pushed down by three springs, so
The joining ball 26 is located in the fixing groove 28. In FIG. 4 showing the attachment part, reference numeral 36 indicates a potentiometer, which measures the amount of movement of the joining cylinder 24, in other words, the amount of elevation of the tool stand 13.

The contactor 37 comes into contact with a part of the tool stand 13. Reference numeral 38 denotes a steady rest plate, which is used to align with the position correction block 121 on the tool stand 13 side and install the tool stand 13 in a predetermined position and direction.

The steady rest plate 38 has a pin 39 parallel to the ceiling tube plate 3.
is rotatably stopped at the tip of the swing arm 12 by
The torque spring 40' is provided so as to always maintain a parallel position, that is, parallel to the ceiling tube plate 3. 43 is an encoder that measures the amount of rotation of the rotation axis 41 of the walking robot 11.

This encoder is connected to the pivot shaft 41 by a gear. Reference numeral 42 indicates a stroke end IJ mitt switch provided on both rotating machines of the rotating arm 12.

The attachment holder 127 has a cylindrical shape as shown in FIG. 5, and is provided with a ball groove 128 at the lower end into which the joint ball 26 on the attachment 21 side is drilled, so as to compete with the joint cylinder 24 of the attachment 21. It has become. The attachment holder 127 includes the base 1 of the tool stand 13.
26 is fixed, and the base 126 has three parallel pins 10.
9 is rotatably provided around an axis parallel to the axis of the attachment holder 127.

The proximal end of a link 105 is fixed to the upper end of each pin 109, and one torch support plate 101 is attached to the distal end of each link 105. The turning radius of this link 105, that is, the link length is approximately the same as the radius of the tube hole 10. A coupling 111 having a gear 110 formed at the lower end is fixed to each pin 109 with a pin 112. On the other hand, a link rotation motor 113 is fixed to the base 126, a gear 115 is fixed to the drive shaft of the link rotation motor 113 with a pin 114, and the gear 115 is connected to the gear 110 formed on the coupling 111. They mesh together. A plate spring-shaped LS is attached to one end of the upper part of the base 126.
Actuator 117 is fixed by bolt 118,
Also, on the other end side of the upper part of the base 126 is this actuator 1.
A limit switch 119 that can be activated by 17 is fixed. A cam 116 that can contact the LS actuator 117 is formed on one of the links 105, and the link 1
According to the rotation of the limit switch 119, the limit switch 119 is turned on or off via the actuator 117. still,
The purpose of switching the limit switch 119 is to change welding conditions, such as welding current. Base 126
At the top, a cylindrical holding rod 12 is installed across the link 105.
2 is fixed with its axis parallel to the center of the plow of the pin 109, and a spring 123 is interposed in the holding rod 122 to correct the position.

The hook 121 is slidably opposed to the holding rod 122 in the ball direction. This position correction block 121 is for positioning the tool stand 13 in synchronization with the steady rest plate 38 on the attachment 21 side described above, and has a circular head 125 that is smaller than the tube hole 10 formed at its tip. , the proximal end has a prismatic shape. Further, a stopper ring 124 is provided at the tip of the holding rod 122 to prevent the position correction block 121 from coming off, so that even if the circular head 125 should collide with the tube plate 3, the force of the spring 123 will buffer the impact force. Ru. On the other hand, a pencil-shaped ultra-small TIG welding torch 100 is held on the tip side of the support plate 101 with its tip facing the tube hole 10 side.

The flexible cable 103 that supplies the welding shield gas to the welding torch 100' is rotatably supported by the holding plate 104 attached to the base 126, so that the flexible cable 103 will not be bent. In addition, a heat shield plate 120 is fixed to the welding torch 100 side of the holding rod 122, and this heat shield plate 120 has a mirror finish to minimize the heat radiated from the arm during welding, thereby increasing the temperature of the tool. This allows for continuous use. Therefore, when the attachment holder 127 is coupled to the joint cylinder 24 of the attachment 21 described above, the position correction block 120 is iron-coupled to the steady rest plate 38, and the attachment 21 and the tool stand 13 provided with the welding torch 100 etc. are integrated. state.

When the drive motor 35 is driven in this state, the welding torch 100 moves toward and away from the tube hole as the joint tube 24 moves, and the arc length is controlled.
3, the link 105 that draws a circle with the same diameter as the tube hole 10 rotates via the gears 115 and 110, and the welding torch 100 held on the support plate 101 rotates around the tube hole 10. be. Using the automatic seal welding device of this specific example configured to be able to separate the walking robot 11 side and the tool stand 13 side in this way, seal welding of the thin tube plug of a pressurized water reactor is carried out as follows. It will be done.

First, the walking robot 11 is mounted on the water chamber tube plate 3 in advance, and the guide wire 22 is hung from the attachment 21. The guide wire 22 is passed through the attachment holder 127 of the tool stand 13, and then the tool stand 13 is installed at the tip of the guide holder 20 and inserted into the water chamber through the manhole 14. Then, the guide wire 22 is attached to the attachment 2.
This will guide you to attachment holder 1 on the tool stand side.
27 and the joint cylinder 24 of the attachment 21 are easily joined together. At this time, the joint ball 26 is located outside the inner fold of the attachment holder 127, but the joint ball 26 rolls and is pushed up from the fixing groove 28 to the detachment groove 29 section by the force of the spring 30. Then, since the attachment holder 127 moves while touching the inner circumferential surface of the attachment holder 127, the attachment holder 127 and the joint cylinder 24 are brought together (FIG. 6b). When the attachment holder 127 is further pushed in and the pawl groove 128 of the attachment holder 127 comes to the part of the detachment groove 29 where the bonded ball 26 is located, the bonded ball 26 moves into the ball groove 1.
At the same time as it fits into the fixing groove 28, it moves together with the fixing holder 27 to the fixing groove 28 by the reaction force of the spring 30. After this,
Since the joining ball 26 and the ball groove 128 move in an entangled state, the attachment holder 127 and the joining tube 2
4 are integrated, and the tool stand 13 is attached to the attachment 21 of the walking robot 11 (FIG. 6a). Joint tube 24
Since the attachment holder 127 and the attachment holder 127 are only iron-coupled, they can rotate around the joint cylinder. However, at the same time as mounting, the steady rest plate 38 and the position correction block 121 are engaged to prevent the tool stand 13 from rotating. Steady rest plate 3
8 can rotate to the vertical position against the force of the torque spring 40 if the alignment with the correction block 121 is not sufficient. By doing this, it will fit in the proper position. After mounting and locking, the motor 35 is driven to rotate the ball screw 33 and the tool stand 13 integrated with the joint 24 is raised.

This amount of rise is determined by the amount of rise of the boresiometer 3 in contact with the base 126.
You can know by 6. Since the upper and lower ends of the lift are detected by limit switches (not shown) (only the upper end is shown with reference numeral 42), overruns and the like can be prevented. Tool stand 1
When the tool stand 13 is located at the proper position by the upward movement of step 3, the position correction block 121 is inserted into the tube hole 10.
Only the tip (circular head 125) is inserted. At this time, it is possible to make a slight positional correction for vibrations that make it difficult for tool alignment to occur and for poor positioning of the arm 12 of the walking robot 11. Since the amount of movement of the welding torch 100 on the tool stand 13 can be detected by the potentiometer 36, the welding arc signal can be output when the distance between the welding torch 100 and the lip of the plug 102 is at the appropriate position, or the work place can input the signal. Welding starts.

Thereafter, the arc current can be detected and the arc length can be controlled by vertical movement of the lifting device of the attachment 21. At the start of the arc, the welding torch 100
It turns by the drive of 3.

As shown in FIG. 7, this movement is a turning movement along the plug grip, and the cable does not twist due to rotation, allowing endless welding movement. Further, the tool shape is greatly simplified without the need for complicated joints such as slip rings. As the welding torch 100 rotates, the cam portion 116 of the link 105 intermittently pushes the LS actuator 117 away from the limit switch 119, turning ON-
Make the OFF signal come out. This signal, which is generated as many times as there are corners of the cam 116, is used when there is a need to change welding conditions during rotation. Further, it is preferable to select a polygonal shape for the number of pulses as necessary. When seal welding of the plug is completed, the motor 35 is reversed and the tool stand 1 is moved together with the joint cylinder 24.
3 is lowered to a position having an appropriate distance from the tube plate 3, and stops there. After that, the walking robot 11 is guided to the next welding location by walking, and then the tool stand 13 is raised again to start the next welding operation. After seal melting is completed, the tool stand 13 is removed.

When the fixed holder 27 of the attachment 21 is pushed up by a removal jig (almost the same as the one shown by reference numeral 20) that supports the tool stand 13, the joining ball 26 is also pushed up at the same time and moves from the fixed groove 28 to the detachment register 29 (the second (See Figure 6b). In this state, the attachment holder 12
When the 7 side is pulled down, the ball groove 128 and the joint ball 26 are disengaged with the joint ball 26 remaining in the detachment groove 29. After that, the procedure is the reverse of the installation procedure, and the tool stand 13 can be removed using the guide wire 22 without entering the water chamber outside the manhole 14. According to the automatic seal welding device of the present invention, the welding torch 10
0 can be guided under the tube hole 10 with high positional accuracy, and all of the installation, positioning, arc length control, movement, and removal of welding equipment can be performed from outside without the operator entering the water chamber. In addition, in this specific example, a plug 102 is installed in the pongee pipe 4 of the steam generator.
Since this is seal welding for packing, the materials to be welded are the thin tube 4 and the plug 102, which are fixed to the tube material 3 as well.

Further, the hole into which the tap shaft of the walking robot is inserted refers to the tube hole 10. However, when plugging into a ceiling with multiple holes, the holes refer to holes in the ceiling. As described above in detail based on one specific example, the automatic seal welding device of the present invention can reliably guide the welding torch under the hole by remote control, and can also control the arc length and move the welding torch around the hole. Rotational movement can be performed automatically.
In addition, by separating the attachment and attachment holder, the tool table holding the welding torch etc. can be moved to a remote location such as outside the water chamber. It can be controlled, moved, and removed.

[Brief explanation of drawings]

Figure 1 is a partially cutaway perspective view of the steam generator of a pressurized water reactor, Figure 2 is an enlarged perspective view of the water chamber of the steam generator in Figure 1, and Figure 3 is a welded part. FIG. 3 is an explanatory diagram showing an overview of device installation work. FIG. 4 is a diagram showing the walking robot side attachment portion of the automatic seal welding apparatus according to the present invention, in which a is a central longitudinal sectional front view, b is a right side view thereof, and c is a sectional view taken along the line A-A. Figure 5 shows the tool stand of the welding device, where a is a cutaway front view, b is a partially cutaway right side view, c is a plan view, and d is a view excluding the heat shield plate and position correction block. FIG. 3 is a plan view showing links. FIG. 6 is a central longitudinal cross-section of the attachment holder in a state where it is iron-coupled with the attachment, with a showing the attached state and b showing the detached state. Figures 7 a to c are diagrams explaining the movement of the torch support plate, Figure 8 is a diagram showing a welding device in which a tool stand is attached to a walking robot, and a is a partially cutaway front view; FIG. In the drawing, 3 is a ceiling tube plate (ceiling), 4 is a pongee tube, 1 is a tube hole (a hole in the ceiling), 1 is a walking robot, 12 is a rotating arm, 1
3 is a tool stand; 21, 127 are attachments and attachment holders that constitute mounting members; 24, 25, 26;
27 and 30 are the main members constituting the attachment: a joint tube, a slide guide, a joint ball, a fixed holder, and a spring; 100 is a welding torch; 101 is a torch support plate; 102 is a plug; 105 is a link; 126 is a base; 128 is a ball groove. Figure 3 Figure 4 Figure 1 Figure 2 Figure 4 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. A plurality of tap shafts are inserted into a hole in the ceiling, which is one of the materials to be welded, and then expand and tightly contact the hole. A walking robot that moves in a hanging state along the ceiling by fitting into the next hole, an attachment that is attached to the walking robot and can move toward and away from the hole, and an attachment that is detachable from the attachment. an attachment holder provided in the attachment holder, a tool stand attached to the attachment holder, and a plurality of parallel links that hold the welding torch and allow the welding torch to draw a circle with approximately the same diameter as the hole. An automatic seal comprising: a torch support plate provided on the tool stand; and a drive motor that moves the attachment toward and away from the hole and controls the arc length of the welding torch that rotates around the hole. Welding equipment.