JPH0252589B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is an automatic method for welding circular fillet welds to each tube end of a large number of heat transfer tubes to a tube sheet in, for example, a heat exchanger, a boiler, etc. It is related to welding machines.

[Prior art] To weld heat exchanger tubes to this tube sheet, an NC-controlled automatic welding machine is used and the welding machine is moved from one welding part to another according to a program in which welding positions, order, etc. are set in advance. The welding head 90 is moved vertically and horizontally to a predetermined welding position, which is the protruding end of a large number of heat transfer tubes 11 inserted (set) in the tube plate 15 in advance, as shown in FIGS. 1 and 2, and the welding head 90 is automatically welded. The guide fitting 91 of the automatic welding head 90 attached to the head stand 50 of the machine 20 is advanced and inserted into the heat exchanger tube 11, and after supporting and fixing the welding head 90 at an accurate welding position, the guide fitting 91 is moved forward and inserted into the heat exchanger tube 11. By rotating the welding electrode 97 and welding wire 98 attached to the rotating shaft 95 about the axis of the heat exchanger tube 11
Fillet welding is performed between the circumference of the tube plate 15 (section W in FIGS. 1 and 7).

[Problems to be Solved by the Invention] Even when NC control is used to ensure accuracy in positioning the automatic welding head, heat exchanger tubes cannot be easily adjusted due to the relative positioning settings between the automatic welding machine and the heat exchanger. In the case of large heat exchangers, the number of heat transfer tubes may reach several hundred, and there may be errors in the pitch of the heat transfer tubes that are inserted into the tube sheet in advance. Therefore, even if the position of the automatic welding head is moved accurately from one welding part to another, there may be a positional error between the heat exchanger tube and the automatic welding head, and the position between the heat exchanger tube and the welding head may be For example, misalignment of about 0 to 3 mm will occur in the welding process, and it is difficult to accurately and repeatedly match the automatic welding head to each predetermined welding position. Currently, welding is often performed while making adjustments.

[Means for solving the problem] A welding head that can move forward and backward toward the end of a pipe is provided, a guide fitting inserted into the pipe is provided at the tip of the welding head, and a welding electrode is provided near the guide fitting. In an automatic tube sheet welding machine, which is equipped with a welding wire and a welding wire rotatable about the axis of a guide fitting, and which welds a tube sheet and a tube by positioning by the movement of a bracket, the welding wire moves back and forth along a bracket arm. The head stand is composed of a cylinder frame, a hanger, a head fixture, etc., the welding head is attached to the head fixture, the front horizontal axis and the rear horizontal axis passing through the head fixture are fixed to the hanger, and the head fixture is attached. The head fixing device is supported so as to be slidable from side to side, and the head fixing device is positioned at a predetermined position on the hanger by applying pressing force from the elastic body from left and right to the front and rear portions of the hanger, and the vicinity of the front, rear, left, and right corners of the hanger are moved. By supporting the cylinder frame with compressed elastic bodies, the hanger can be moved up and down, and the welding head is made to bounce up and down and left and right against the cylinder frame of the head stand, and the cylinder frame is moved back and forth by the cylinder. Make it possible to move in the direction.

[Function] In the present invention, a welding head is attached to a head fixture, and the head fixture is supported with a horizontal axis so as to be movable left and right with respect to a hanger, and the front and rear of the head fixture are each supported by elastic bodies. Since the welding head is located at a predetermined position such as the center of the hanger, it is not only possible to move the welding head parallel to the hanger from side to side, but also to move it in such a way that the axis of the welding head is tilted to the left and right. Become. or,
Since the four corners of the hanger are attached to the cylinder frame by elastic bodies so that the hanger can move vertically, the hanger can not only move vertically in parallel, but also move vertically so as to tilt.

Therefore, the welding head can be moved vertically and horizontally with respect to the cylinder frame by external force, and
It is also possible to tilt vertically and horizontally, and since each elastic body provided in the horizontal and vertical directions is compressed to bias the hanger and head fixture, the welding head will not move when no external force is applied to the welding head. It is fixed in place relative to the cylinder frame.

[Embodiment] In an embodiment of the automatic welding machine according to the present invention, as shown in FIG.
Consisting of a hanger 70 and a head fixture 80,
By attaching the automatic welding head 90 to the head stand 50, it is freely attached to the bracket arm 42.

That is, as shown in FIGS. 3 and 4, the cylinder frame 51 is attached to a guide 63 that is guided and supported by a rail 45 provided on the bracket arm 42 so as to be slidable in the front and rear direction.
Through holes 59 are provided near the four corners of the upper plate 54 of the cylinder frame 51, and suspension shafts 55, 5 that slide up and down are provided.
6, 57, 58 respectively penetrate through the through holes 59, and 2 as a first elastic body provided on each suspension shaft.
By positioning the springs 661 and 62 so as to sandwich the upper plate 54, the suspension shaft is
It is elastically and movably attached to the upper plate 54 of the cylinder frame 51 via the bolt 62.

Further, the suspension shafts 55, 56, 57, 58 are provided with respective nuts 55a, 56 having male threads cut and screwed thereto.
A, 57a, 58a are tightened to appropriately compress the springs 61, 62, and each nut is screwed in by the desired amount to urge the hanger 70 (described later) with a stronger force against the cylinder frame 51. This makes it possible to regulate and adjust the amount of vertical movement and rotation of the hanger 70, that is, the welding head 90 in the vertical direction.

The inner diameter of each through hole 59 is made larger than the outer diameter of each of the suspension shafts 55 to 58 by a desired amount, so that the suspension shaft can be tilted back and forth. It allows rotation.

A front support shaft 65 is provided so as to connect the lower ends of the first suspension shaft 55 and the second suspension shaft 56 located on the left and right front sides among the suspension shafts passing through each through hole 59 with a shaft. 65, the front support part 73 of the hanger 70 is pivoted to the suspension shaft, and a rear support part 74 is also provided at the rear of the hanger 70. 4 suspension shaft 58 (not shown),
The rear support portion 74 is also pivoted by the rear support shaft 68 .

Furthermore, this hanger 70 has a U-shaped cross section, and the front horizontal axis 75 and the rear horizontal axis 76 are connected to the left and right side walls 7.
1, 72, and both the front and rear horizontal shafts 75, 76
The head fixing device 80 is attached to the inside of the hanger 70.
The structure is such that it can be installed in such a way that the

The head fixing device 80 is connected to the front and rear horizontal axis 7.
5, 76, and between the head fixture 80 and the hanger left wall 71 and between the head fixture 80 and the hanger right wall 72, there are second
Two springs 77 and 78 having substantially the same spring constant are inserted as elastic bodies in a resilient state. Moreover, as shown in FIG. 4, the cylinder frame 5
Side walls 51a, 52 protruding downward on the left and right sides of 1
The left and right side walls 71, 7 of the hanger 70 are on the inner surface of b.
The liners 83 and 84 are attached to the hanger 70 in contact with the hanger 70, respectively, to prevent the hanger 70 itself from wobbling or moving in the left-right direction.

Therefore, when the head fixture 80 is not performing welding work, that is, in a free state where it is not subjected to external force,
It is always positioned at the reference position in the left and right horizontal directions by springs 77 and 78 as second elastic bodies.
The reference position of the head fixture 80 in the vertical direction is held at a predetermined position by a first elastic body, which is a spring provided above and below the upper plate 54 of the cylinder frame 51.

Further, as shown in FIG. 3, the head fixing device 80 has front and rear ends 81, 82 in an arc shape, and a liner 8 attached to the front and rear walls 52, 53 of the cylinder frame 51.
5 and 86 to restrict movement of the head fixing tool 80 itself in the front-rear and horizontal directions, while allowing rotation in the up-down direction. Note that it is desirable that the rear end 82 of the head fixture be in contact with the liner 86 provided on the rear wall 53. In addition, the thickness of the liners 85 and 86 can be made thinner so that the front and rear ends 8 of the head fixture 80 can be made thinner.
If a desired spacing is provided between the liners 85, 86 and the liners 85, 86, the rotational force in the vertical direction or the amount of movement in the longitudinal direction of the head fixture 80 can be adjusted. Furthermore, suspension shafts 55, 56, 57, 5
The degree of rotation can also be adjusted by changing the amount of compression of the front and rear springs attached to 8 using a nut.

As described above, in this embodiment, the first suspension shaft 55 to the fourth suspension shaft 58 and the springs 61, 62 enable vertical movement of the cylinder frame 51, that is, movement in the vertical vertical direction and rotation in the vertical direction. , and the front and rear horizontal axes 75 and 76 and the second elastic body 77,
The automatic welding head 90 fixed to the head fixture 80 has a guide fitting 91 at its tip as shown in FIG. has a conical cap body 92 at the tip and a cylindrical chest body 93 at the center.
and a flange 94 extending outward at the rear end.
The structure has the following.

The outer diameter of the body portion 93 of the guide fitting 91 is made smaller, for example, by about 0.5 mm in diameter than the heat exchanger tube 11, so that the guide fitting 91 can be inserted smoothly into the inside of the heat exchanger tube 11. is desirable. Note that this guide fitting 91 can be replaced depending on the size of the heat transfer tube 11.

Further, the head stand 50 is, for example, a cylinder frame 5.
The welding machine 20 is moved forward and backward relative to the bracket 40 by two air cylinders 68 provided between the left and right walls of the welding machine 1 and the bracket stand 41 of the welding machine 20.
The bracket arm 42 to which the head stand 50 is attached is attached to the vertical frame 30 by the bracket stand 41.
Attach to.

As shown in FIGS. 5 and 6, this vertical frame 30 has a vertical movement servo motor 33 at its upper end that moves the bracket base 41, and a vertical drive shaft configured as a ball screw rotated by the servo motor 33. 34 and a vertical rail 32 on the front surface, and the bracket base 4
1 is slidably attached to the vertical rail 32, and is moved up and down according to the drive shaft 34 by means of a ball nut provided on the back side of the bracket stand 41.

Further, the vertical frame 30 is attached so as to be slidable in the horizontal direction by horizontal rails 22 provided at the upper and lower positions of the main body frame 21, and is rotated by a servo motor 23 for horizontal horizontal movement provided on the side of the main body frame 21. The horizontal drive shaft 24 configured as a ball screw and a ball nut provided on the back side of the vertical frame 30 allow movement from side to side.

Further, the motor and the ball screws 24, 34 are connected by a shaft joint with no play in the axial direction. In this way, the movement of the bracket table 41 in the horizontal and vertical directions is carried out by a drive system such as a servo motor, a ball screw device, etc. that has no play in the axial direction of the ball screw and ball nut, and has good screw efficiency, so that the welding head 9
0 can be accurately positioned in the vertical and horizontal directions.

The driving servo motors 23 and 33 for horizontal and vertical movement are controlled by an NC control device built into a control panel 26 provided at the rear of the main body frame.

A base 27 is provided at the bottom of the main body frame 21.
Adjustment bolt 2 for longitudinal and horizontal fine adjustment
9 is provided, and when positioning the heat exchanger 10 and the welding machine 20 relatively, the heat exchanger 10 and the welding machine 20
The distance and parallelism between the two can be adjusted.

In this way, the automatic welding machine 20 for tube sheets according to this embodiment
This enables accurate horizontal and vertical positioning using NC-controlled servo motors 23 and 33, and also allows automatic welding head 90 to be mounted on bracket 40.
Since the cap 92 at the tip of the guide fitting 91 has a conical shape, the automatic welding head 90 can be accurately moved to the welding position and supported.

In other words, the horizontal movement servo motor 2
3 and the vertical movement servo motor 33 to move the bracket stand 41 to a predetermined position, that is, the automatic welding head 90 to the predetermined position where the tube sheet 15 is to be welded, the air cylinder 68 provided on the head stand 50
When the automatic welding head 90 is moved forward, even if the position of the automatic welding head 90 has some error with respect to the predetermined welding position, the cap body 9 of the guide fitting 91
Since the cap body 92 has a conical shape, if the tip of the cap body 92 is located inside the heat transfer tube 11, the automatic welding head 90 is loosely attached to the bracket 40, and the cap body 92, that is, Guide fitting 9
The position of the automatic welding head 90 is corrected in accordance with the advance of the automatic welding head 90.

In other words, the head fixing device 50 is
Since the head fixing device 80 is movably attached to the hanger 70 with the second elastic bodies 77 and 78, an error of, for example, about 0 to 3 mm in the horizontal (left and right) direction due to movement of the head fixing device 80 with respect to the hanger 70 occurs. is absorbed by the second elastic bodies 77 and 78, and error correction based on horizontal positional deviation and direction deviation is performed as the guide fitting 91 moves forward. ,56,57,
58, and 2 which is the first elastic body provided on each suspension shaft.
Since the hanger 70 is loosely attached to the cylinder frame 7 by the springs 61 and 62,
By moving up and down with respect to
1 and 62, and error correction based on the vertical positional deviation and directional deviation is performed as the guide fitting 91 moves forward.

Further, the heat exchanger tube 11 and the welding machine 20, that is, the heat exchanger tube 11
Even if the parallelism between the welding head 90 and the guide fitting 91 at the tip of the welding head 90 is slightly out of alignment, the welding head 90 is fixed to the front and rear suspension shafts 55 to 59 with the head fixing device 80 at the base end equipped with springs 61 and 62. Since the front and rear ends 81 and 82 are arcuate and connected to the cylinder frame, they can be rotated in the front and rear directions, so that the guide fittings 91 move forward into the heat exchanger tubes 11. Therefore, differences in parallelism can be absorbed.

Then, as shown in FIG. 7, the flange 94 of the guide fitting 91 comes into contact with the end 11a of the heat exchanger tube 11, and after the automatic welding head 90 stops moving forward, the rotary shaft 9
Welding electrode 97 and welding wire 98 attached to 5 rotate around the axis of guide fitting 91,
The circumference W of the heat exchanger tube 11 is fillet welded to the tube plate 15, and after welding is completed, the automatic welding head 90 is moved back together with the head stand 50 by the air cylinder 68, and the guide fitting 91 is pulled out from the heat exchanger tube 11 and moved to the next position. The large number of heat transfer tubes 11 and tube sheets 15 are moved by the horizontal movement servo motor 23 and the vertical movement servo motor 33, etc., and are accurately positioned in the same manner as described above.
Repeat welding in sequence.

Note that when inserting the cap body 92 and body part 93 of the guide fitting 91 into the heat exchanger tube 11, the amount of movement in the longitudinal direction and the amount of rotation in the vertical direction of the automatic welding head 90 is regulated by the repulsive force that the automatic welding head 90 receives. is the third
The support is not limited to the case where the liners 85, 86 attached to the front and rear walls 52, 53 of the cylinder frame 51 and the front and rear ends 81, 82 of the head fixture 80 are supported as shown in FIG. A support member 69 having an elongated hole is attached to the left and right side walls of the cylinder frame 51 by hanging down, and a rod 69a is made to protrude from the welding head 90 in the left and right direction, and this rod 69a is positioned in the elongated hole. You can also do it. Alternatively, as shown in FIG. 9, the bracket 40 and head stand 50 attached to the vertical frame 30 can be attached to the vertical frame 30 in an upside-down state compared to those described above. In this case, the first elastic body can be The four suspension shafts 55 to 58 provided serve as suspension shafts that support the welding head 90, hanger 70, etc. from below.

Furthermore, the hanger 70 is mounted inside the box-shaped cylinder frame 51 as shown in FIG. 54 and hanger 7
A spring 100 or the like as a first elastic body is interposed between the hanger 70 and the lower wall 67 of the cylinder frame, and the hanger 70 is freely attached in the vertical direction with the hanger 70 elastically springing against the cylinder frame 51. There is also.

[Effects of the Invention] The present invention has a guide fitting to be inserted into a pipe at its tip, and a welding electrode and a welding wire are provided near the fitting so as to be rotatable about the axis of the guide fitting.
In addition, in an automatic tube plate welding machine for welding a tube plate and a tube, the welding head is equipped with a welding head that can move forward and backward toward the end of the tube, and the head stand is composed of a cylinder frame, a hanger, a head fixture, etc., The head fixture is attached so that it can move horizontally relative to the hanger, and the hanger is movable vertically relative to the cylinder frame. When the head stand such as a cylinder frame is moved forward and the guide fitting is inserted into the pipe, the head stand is used to prevent misalignment in the position and direction of the pipe and the welding head. Since the welding head is designed to be able to be absorbed, the guide fitting and head stand work together to correct any positional errors that exist between the heat exchanger tube and the welding head, that is, between the welding location and the welding machine body. , increase the precision and efficiency of automatic welding,
This tube can promote automation, and can automatically and reliably weld a large number of heat exchanger tubes to a tube sheet in sequence according to a preset program, resulting in a significant labor-saving effect. The present invention provides an automatic plate welding machine.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the installation state of an automatic welding machine and a heat exchanger according to the present invention, Fig. 2 is a diagram showing the main parts of the automatic welding machine according to the present invention, and Fig. 3 is a part of the head stand. 4 is a partial sectional front view of the head stand indicated by the ~ line arrow in FIG. 3, FIGS. 5 and 6 are front and side views of the automatic welding machine, respectively, and FIG. 7 is a welding head. FIGS. 8, 9, and 10 are longitudinal cross-sectional views showing the state when the guide fitting is inserted into the heat transfer tube, and FIGS. 8, 9, and 10 are views showing other embodiments, respectively. 10... Heat exchanger, 20... Automatic welding machine, 21
...Body frame, 23 ...Servo motor, 25
... Control panel, 30 ... Vertical frame, 33 ... Servo motor, 40 ... Bracket, 50 ... Head stand, 51 ... Cylinder frame, 55 to 58 ...
... Suspension shaft, 61, 62... First elastic body, 65,
66... Support shaft, 70... Hanger, 75, 76
...Horizontal axis, 77, 78...Second elastic body, 80
...Head fixing tool, 90 ...Automatic welding head, 9
1... Guide metal fitting, 95... Rotating shaft, 97... Electrode, 98... Welding wire.

Claims (1)

[Claims] 1 Equipped with a welding head that can move forward and backward toward the end of the pipe, a guide fitting inserted into the pipe at the tip of the welding head, and a welding electrode and a welding wire placed near the guide fitting along the axis of the guide fitting. In an automatic tube sheet welding machine, the welding head is positioned to weld the tube sheet and the tube by moving the bracket vertically and horizontally. The head stand, which can be moved forward, is made of cylinder frame, hanger,
The welding head is attached to the head fixture, and the front horizontal axis and the rear horizontal axis passing through the head fixture are fixed to a hanger, so that the head fixture can be slid left and right. At the same time, the head fixing device is positioned at a predetermined position relative to the hanger by applying pressing force from the elastic body from the left and right at the front and rear portions of the head fixing device, and the elastic body compresses the vicinity of the front, rear, left, and right corners of the hanger. By supporting the hanger with its body to the cylinder frame, the hanger can be moved up and down with respect to the cylinder frame, so that the welding head can be made to bounce horizontally and vertically against the cylinder frame of the head stand, and An automatic tube plate welding machine characterized by having a structure in which a cylinder frame is moved forward and backward along a bracket arm by a cylinder.