JPH09285893A - Automatic welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily make an equipment and the production without being limited with mounting weight and to obtain the running stability. SOLUTION: When a guiding and supporting body 4 is wound on the outside circumference of a circular-cylinder tube 1A, the guiding and supporting body 4 is engaged to a sprocket on a running carriage 3, the running carriage 3 is held on the outside circumference of the circular-cylinder tube freely running, the running carriage 3 is guided along a welding line part 2, and it is run in the state of being attracted on the outside circumference of the circular-cylinder tube 1A with an electro-magnetic wheel 5. Further, the running carriage 3 can be run in a stable locus along the outside circumference of the circular-cylinder tube 1A with the magnetic attracting function of this electro-magnetic wheel 5 and the holding force of the guiding and supporting body 4, and so, even the weight of the running carriage 3 and a welding head part 20 is heavy, the running carriage 3 can be prevented from dropping down from the circular- cylinder tube 1A, and the strength of the running carriage 3 in the running time can be kept.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic welding device for butt-welding cylindrical pipes, and more particularly to an automatic welding device suitable for welding the outer periphery of a cylindrical pipe as a welding object.

[0002]

2. Description of the Related Art For example, a feed water heater installed in a thermal power plant or the like is welded by abutting cylindrical pipes, but at the time of welding, the cylindrical pipe itself is fixed and the structure is internal. Therefore, the cylindrical pipe cannot be rotated and welded. For this reason, when welding by hand, a large cylindrical tube with a diameter of several meters requires a large amount of work in an unreasonable posture for the operator, and not only is it too burdensome, but also a lot of work is required for setup work. I was trying.

Therefore, conventionally, an automatic welding apparatus has been proposed and put into practical use in which a carriage is made to travel on a traveling rail installed on the outer periphery of a cylindrical pipe for automatic welding.

Prior arts of the automatic welding apparatus are shown in JP-A-59-215298 (hereinafter referred to as first prior art) and JP-A-6-71485 (hereinafter referred to as second prior art). There are technical ones.

As shown in FIG. 5, the first prior art described above has a chain-shaped rail 103 installed on a steel plate 101 having a curved surface, and a trolley 1 traveling on the rail 103.
02. The rail 103 is fixed to the steel plate 101 with the magnet 104, so that the welding target line 10
It is laid along 5. In this case, in the first embodiment of the prior art, as shown in FIG. 6, the chain-shaped rail 103 and the metal strip plate 106 integrated with the rail 103 are fixed to the steel plate 101 by the magnet 104.

On the other hand, as shown in FIG. 5, a torch 107 and a gripping mechanism 108 for gripping the torch 107 are mounted on an upper portion of the traveling carriage 102, and a rail 103 and a gripping portion 103 are mounted on a lower portion thereof as shown in FIG. Sprocket mating 109
And a roller 110 that clamps both ends of the metal strip 106.
And a wheel 111 for preventing the vehicle from falling over.
Therefore, when the sprocket 109 is driven, the sprocket 109 runs on the steel plate 101 along the rail 103.

In the second prior art, as shown in FIG. 7, of the piles 51a and 51b that are butted against each other,
An iron plate 53 arranged on the side surface of the upper pile 51a in parallel to the planned welding line 52, a rail 54 provided on the iron plate 53 and having a chain 54a, a holder 56 for holding the welding torch 55, and Rail 5 with holder 56 mounted
4 is provided with a traveling carriage 58 that can move 360 degrees or more with respect to the direction of the arrow 57, a metal fitting 60 that locks the cords 59, and a guide rail 61 that moves the cords 59 as the traveling carriage 58 moves. ing.

Although not shown, the traveling carriage 58 has a sprocket fitted to the chain of the rail 54, a motor for imparting a rotational force to the sprocket, and two systems of rollers for assisting traveling. When fitted to the chain, an attractive force is generated between the iron plate 53 and the iron plate 53 due to the magnetic force of the magnet, and the sprocket and the roller are pressed against the rail 54, so that the welding apparatus main body is placed on the rail 54 in a well-balanced manner. I am trying to do it. Therefore, during welding, when the traveling carriage 58 moves on the rail 54 along the arrow 57, the welding torch 55 welds the position of the planned welding line 52 and welds the pile 51a to the lower pile 51b.

[0009]

By the way, the prior art described above does not consider the following points. That is, in the first conventional technique, the steel plate 10 to be welded is used.
Since the rail 103 is magnetically installed on the first rail, if the rail 103 is to be used as a welding object in a large-diameter cylindrical pipe, the rail 103 must be accurately fixed around the circumference of the cylindrical pipe. Not only is it troublesome to perform the installation work, but there is a problem that it is not preferable in terms of safety.

Further, when the diameters of the cylindrical pipes are different, various rails 103 corresponding to the diameters have to be manufactured, so that there is a problem that the cost increases accordingly. This problem,
Also in the second conventional technique, since it is necessary to manufacture various iron plates 53 and rails 54 installed on the outer periphery of the pile 51a,
The same applies. In addition, in the case of the second conventional technique, as described above, since not only the rail 54 but also the iron plate 53 is used, the space becomes large, and there is a problem that it is difficult to secure a storage place in the field work.

Further, in the first prior art, the rail 10
3 is fixed by the magnet 104, and the wheel 1
Since 11 is fixed to the steel plate 101 by its own magnetic force, if the weight of the carriage 102 is too heavy, the traveling becomes unstable and there is a risk of dropping, so that there is a problem that the weight of the carriage mounted is limited. This problem also applies to the second prior art. That is, in the second conventional technique, the iron plate 53 cannot be formed to be too thick because of the need to process the iron plate 53 and the need to install it on the pile 51a, and therefore a thin iron plate must be used. , On this rail 54
When installed, it is difficult to increase their strength too much. In addition to this, the magnet holder provided on the traveling carriage 58 does not fix the carriage itself, but has a holding function for maintaining the positional relationship between the traveling carriage 58 and the iron plate 53. Therefore, if the weight of the truck is heavy, the strength of the truck during traveling becomes unstable and the weight is limited.

In view of the above-mentioned problems of the prior art, an object of the present invention is that installation work can be performed easily and safely, and even if the diameter of the cylindrical pipe is different, it is not necessary to manufacture it according to it. Another object of the present invention is to provide an automatic welding device capable of preventing dropping of a heavy load on a trolley and obtaining stability during traveling.

[0013]

According to the present invention, when cylindrical cylindrical objects to be welded made of a magnetic material are butted against each other,
In an automatic welding device that travels along the outer circumference of one work piece and welds the welding line parts that are abutted against each other, on the outer circumference of the work piece in a state of being adsorbed on the outer circumference part of the one work piece. And a traveling carriage that can travel along the welding line around the outer periphery of the workpiece to be welded, and guides the traveling of the traveling carriage along the welding line while the traveling carriage is on the outer periphery of the workpiece. The guide-combined holding body, which is sandwiched so as to be able to travel, and the welding head portion, which is mounted on the traveling carriage and welds the welding line portion, has one end portion when wound around an object to be welded. It is characterized in that it has a long string shape in which the traveling carriage is inserted and is wrapped around the outer periphery of the object to be welded and fastened to the other end side.

According to the present invention, when the guide / holding body is wound around the outer periphery of one of the objects to be welded, the guide / holding body holds the traveling carriage on the outer periphery of the one object to be welded and the traveling carriage Is guided along the welding line, and the traveling carriage travels in a state where it is adsorbed to the outer peripheral portion of the object to be welded. Due to this adsorption action and the holding force of the guide / holding body, the traveling carriage is welded to one of the objects to be welded. It is possible to reliably travel along the outer circumference of the object.

Therefore, even if the traveling carriage and the welding head portion mounted on the traveling carriage are heavy in weight, the traveling carriage can be prevented from falling from the object to be welded.
Unlike the second conventional technique, the weight of the load on the traveling carriage is not limited, and the strength of the traveling carriage during traveling can be maintained.

Further, since the guide / holding member is in the form of a long string, and one end thereof is wound around the outer periphery of the object to be welded and fastened to the other end, the diameter of the object to be welded is changed. However, the length can be adjusted by changing the pitch accordingly, so that it is not necessary to make various types according to the size of the cylindrical tube in advance as in the first and second conventional techniques. Therefore, it can be easily dealt with regardless of the diameter. Moreover, the guide / holding body does not have to be manufactured as described above, and it is not necessary to fix it to the steel plate as in the second conventional technique, so that the storage space can be saved. You can

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to FIGS. FIG. 1 is a schematic perspective view for explaining an embodiment in which the automatic welding device according to the present invention is applied to a cylindrical pipe of a water heater, and FIG. 2 is a sectional side view and a plan view for explaining a traveling carriage of the automatic welding device. FIG. 3 is a perspective view showing a welding head portion and a welding power source side mounted on a traveling vehicle, and FIG. 4 is an explanatory view of a main portion showing a guide / holding body.

The automatic welding apparatus of this embodiment constitutes a feed water heater as an object to be welded, and when the cylindrical tube 1A and the cylindrical tube 1B installed so that the axial direction is horizontal, are abutted to each other. A traveling carriage 3 for welding the outer circumference of a weld line portion 2 which is a butt portion, and a traveling carriage 3 capable of traveling on the outer circumference of one cylindrical pipe 1A, and the traveling carriage 3
A guide / holding body 4 is provided on the outer periphery of A for guiding along the welding line portion 2 and for movably holding it. Here, the weld line part 2 is a cylindrical tube 1A and 1B.
Beveling is applied to the portions of the butt against each other.

The traveling carriage 3 travels on the outer periphery of the cylindrical tube 1A, and as shown in FIGS. 2 (a) and 2 (b), the traveling vehicle 3 is magnetically attracted to the cylindrical tube 1A by an exciting force from an electromagnetic coil 18. , The traveling carriage 3 while rotating in the adsorption state
It has electromagnetic wheels 5 for traveling. The electromagnetic wheel 5
Are formed of a magnetic material that can be attracted to the cylindrical tube 1A by magnetic force, and are rotatably supported by front and rear parts on both sides of the carriage main body 3a so that a total of four can be rotated by a driving means. The drive means is, as shown in FIGS. 2 (a) and 2 (b), the carriage main body 3a.
A drive motor 6 installed on the bottom side of the speed reducer 7, a speed reducer 7 connected to the drive motor 6, a pinion 8 mounted on the output shaft of the speed reducer 7, and two gears 9 meshing with the pinion 8. Each of these gears 9 and 9 is in mesh with each other, and is composed of a gear portion 10 provided integrally with two electromagnetic wheels 5. In addition, in this example, the two electromagnetic wheels 5 having the gear portion 10 are not shown in FIG.
As shown in (b), it is located on one front and rear part of the carriage main body 3a. That is, when the electromagnetic wheel 5 is attracted to the outer circumference of the cylindrical tube 1A, the rotational force from the drive motor 6 is transmitted to the pinion 8 by the speed reducer 7, and the rotational force of the pinion 8 is transferred to the two gears 9. By being transmitted to the respective gear parts 10 via the, the electromagnetic wheels 5 rotate and run while being adsorbed on the outer peripheral part of the cylindrical tube 1A.

Further, the traveling carriage 3 has a holding body 4 which also serves as a guide.
And a sprocket 11 as a rotating body that engages with the traveling carriage 3 and guides the traveling of the traveling carriage 3. This sprocket 1
Reference numeral 1 denotes a gear which meshes with a guide / holding body 4 which will be described later. Has been formed. Therefore, the traveling carriage 3
Has electromagnetic wheels 5, drive means, and sprockets 11.

On the other hand, the guide / holding body 4 is composed of a chain having a length sufficient to be wound around the outer periphery of a large cylindrical tube 1A, as shown in FIGS. It has hanging jigs 16a and 16b. The guide / holding body 4 is normally in a state in which one end of the chain is connected to one end of the tightening clamp 14 via one chain hanging jig 16a, and when welding the cylindrical tubes 1A and 1B, The other end of the chain is inserted into the chain insertion portion 3b provided in the bogie body 3a of the traveling bogie 3 and meshes with the sprocket 11, and is further wound around the outer periphery of the cylindrical tube 1A and connected to the tightening clamp 14. By being connected to the chain hooking jig 16b of No. 1 and by operating the tightening clamp 14 to apply tension, it can be wound around the outer periphery of the cylindrical tube 1A along the weld line portion 2. Therefore, the chain insertion portion 3b is formed so that the chain can be inserted into the front and rear portions of the carriage main body 3a of the traveling carriage 3.

Therefore, the guide / holding body 4 is the cylindrical tube 1
When it is wound around the outer circumference of A, it meshes with the sprocket 11 of the traveling carriage 3, so that the traveling carriage 3 is clamped to the outer peripheral portion of the cylindrical tube 1A, and when the traveling carriage 3 travels, the traveling carriage 3 travels. I try to guide you.

In this case, in the guide / holding body 4, if the tightening force of the tightening clamp 14 is large and the holding force against the traveling carriage 3 is too strong, it becomes difficult for the traveling carriage 3 to travel on the outer periphery of the cylindrical tube 1A. It has a tensioner 15 that applies an appropriate tension to the chain so that the carriage 3 can travel. This tensioner 15 is shown in FIG.
As shown in FIG. 5, it is composed of a spring connected between the tightening clamp 14 and the other chain hanging jig 16b.

Further, the guide / holding body 4 is the cylindrical tube 1
When winding around the outer circumference of A, a slip wheel 17 is provided to facilitate the winding. In order to allow the guide / holding body 4 to wind around the outer periphery of the cylindrical tube 1A while sliding around the outer periphery of the cylindrical tube 1A, a plurality of the slide wheels 17 are provided at the same position as the chain as shown in FIG. .

On the other hand, as shown in FIG.
A welding head portion 20 for welding the welding line portion 2 of the cylindrical tubes 1A and 1B is mounted. The welding head portion 20 is mounted on a triaxial slide base 22 installed on the carriage main body 3a as shown in FIG. 3, and the welding torch 21 has an X axis and a Y axis.
By moving in the three directions of the axis and the Z axis, the welding line portion 2 is positioned. Further, the welding head portion 20 and the triaxial slide base 22 are connected to a welding power source welding power source 24 and a welding control device 23 which are installed at predetermined positions similarly to the control portion 30 of the traveling carriage 3 shown in FIG.

Since the automatic welding apparatus of the embodiment has the above-mentioned structure, its handling will be described below.

Now, as shown in FIG. 1, when two cylindrical tubes 1A and 1B to be welded to each other are installed horizontally and when they are in a state of being butted to each other, the butted welding line 2 For welding, first, the guide / holding body 4 and the traveling carriage 3 on which the welding head 20 is mounted are prepared, and the electromagnetic wheels 5 of the traveling carriage 3 are attracted to a predetermined position of one cylindrical tube 1A. Let Next, as shown in FIG. 2, one end side of the guide / holding body 4 to be connected to the chain hooking jig 16b is passed through one chain insertion portion 3b of the carriage main body 3a of the traveling carriage 3 to be meshed with each sprocket 11. At the same time, it is pulled out from the other chain insertion portion 3b, one end side of the pulled out chain is hung around the outer circumference of the cylindrical tube 1A, and then the chain hanging jig 16b of the guide / holding body 4 is placed at a length that does not cause slack. The guide / holding body 4 is wound around the outer circumference of the cylindrical tube 1A along the weld line portion 2 by connecting and holding the guide / holding body 4 by operating the tightening clamp 14.

As a result, the guide / holding body 4 presses the traveling carriage 3 against the outer peripheral portion of the cylindrical tube 1A, and the electromagnetic wheels 5 of the traveling carriage 3 are attached to the outer peripheral portion of the cylindrical tube 1A by its magnetic force. It remains adsorbed. When the guide / holding body 4 is wound, only the chain removed from the tightening clamp 14 and the tensioner 15 is hung around the cylindrical tube 1A, and then the tightening clamp 14 and the tensioner 15 are connected and fastened to the chain. Good.

After that, when the controller unit 30 shown in FIG. 1 is operated to drive the drive motor 6 of the traveling carriage 3, the power is transmitted to the electromagnetic wheels 10 via the pinion 8, the gear 9 and the gear unit 10 of the speed reducer 7. And the electromagnetic wheel 10 is a cylindrical tube 1A.
The rolling carriage 3 travels on the cylindrical pipe 1A while being guided by the guide / holding body 4 because it rolls while adsorbing on the outer periphery of Further, when the traveling carriage 3 travels, the welding torch 21 of the welding head portion 20 mounted on the traveling carriage 3 welds the welding line portion 2 on the basis of the previously traced trajectory.

When the traveling of the traveling carriage 3 and the welding by the welding torch 21 are completed for a predetermined distance, for example, when the welding of the half of the circumference of the welding line portion 2 is completed, the clamping clamp for the guide / holding body 4 is clamped. After loosening 14, the guide / holding body 4 is displaced along the outer circumference of the cylindrical tube 1A, and the tightening clamp 1 is moved in the same manner as described above.
When the guide / holding body 4 is wound again by tightening by the operation of 4, the traveling carriage 3 is run along the remaining unwelded weld line portion 2 to weld the weld line portion 2 over the entire circumference. . At the time of welding, it is preferable to divide the welding path into several times in order to prevent the cylindrical tubes 1A and 1B from being deformed by the thermal stress of the welding.

As described above, the automatic welding apparatus of the embodiment causes the guide / holding body 4 to mesh with the sprocket 11 of the traveling carriage 3 when the guide / holding body 4 is wound around the outer circumference of the one cylindrical tube 1A. , The traveling carriage 3 is sandwiched so as to be able to travel on the outer circumference of the cylindrical tube 1, and the traveling carriage 3 is guided along the welding line portion 2, and the traveling carriage 3 is attracted to the outer peripheral portion of the cylindrical tube 1A by the electromagnetic wheels 5. Since the vehicle travels in this state, the traveling carriage 3 can travel on a stable track along the outer circumference of the cylindrical tube 1A due to the magnetic attraction of the electromagnetic wheels 5 and the holding force of the guide / holding body 4.

Therefore, even if the traveling carriage 3 and the welding head portion 20 mounted thereon are heavy in weight, the traveling carriage 3 can be prevented from falling from the cylindrical pipe 1A. Unlike the second prior art, the weight of the load on the traveling carriage is not limited, and the traveling carriage 3
The strength during running can be maintained.

Further, since the guide / holding body 4 is in the form of a long string, and one end thereof is wound around the outer periphery of the cylindrical tube 1A and is fastened to the other end, the cylindrical tubes 1A and 1B to be welded are to be formed. Even if the diameter changes, the length can be adjusted by changing the chain pitch accordingly.
Therefore, unlike the first and second conventional techniques, it is no longer necessary to manufacture various types in advance according to the size of the cylindrical tube,
Therefore, it is possible to easily cope with the problem regardless of the diameter. Moreover, the guide / holding body 4 need not be manufactured as described above, and it is not necessary to fix it to the steel plate as in the second conventional technique, so that the storage space is saved. be able to.

Further, the guide / holding body 4 is in the form of a long string made of a chain as described above, and when it is wound around the cylindrical tube 1A and tightened by the tightening clamp 14,
Since the tension can be obtained, the guide / holding body 4 can be positioned along the entire circumference of the cylindrical tube 1A simply by positioning the necessary portion of the guide / holding body 4 around the cylindrical tube 1A. Therefore, since it is not necessary to position the guide / holding body 4 along the welding line portion 2 over the entire circumference of the cylindrical tube 1A, the guide / holding body 4 can be easily installed, and only that much installation work is required. The danger of time can be avoided.

Further, the cylindrical tube 1 is provided by the holding body 4 which also serves as a guide.
When the traveling carriage 3 is clamped on A, if the force is too large, the traveling carriage 3 may be difficult to travel on the outer periphery of the cylindrical tube 1A, but the guide / holding body 4 has the tensioner 15. Since the spring force of the tensioner 15 gives an appropriate tension so that the traveling carriage 3 can travel,
It is possible to mitigate the increase in the tightening force on the traveling carriage 3 and reliably realize stable traveling of the traveling carriage 3.

Furthermore, since the welding torch 21 of the welding head portion 20 mounted on the traveling carriage 3 is controlled by the welding control device 23 via the triaxial slide base 22, the welding torch 21 is aligned with the welding line portion 2. Since the position can be precisely adjusted, good welding can be performed.

In the illustrated embodiment, the guide / holding body 4 holds the traveling carriage 3 so that if the guide / holding body 4 is tightened too much, the traveling carriage 3 will be inserted into the cylindrical tube 1A.
However, since the traveling carriage 3 can be adjusted to travel on the cylindrical tube 1A by the spring force of the tensioner 15, the tightening force of the traveling carriage 3 on the cylindrical tube 1A can be adjusted appropriately. Can be one. Moreover, in the illustrated embodiment, the guide / holding body 4 is formed of a chain, and when the guide / holding body 4 is wound around the cylindrical tube 1A, the chain may be caught on the outer periphery of the cylindrical tube 1A in the middle, but the sliding wheel 17 is coaxial with the chain. Is provided, it is possible to easily wind the chain around the outer circumference of the cylindrical tube 1A by sliding the sliding wheel 17, and
The guide / holding body 4 can be installed more easily.

In the illustrated embodiment, the guide / holding member 4 is also used.
As an example, the present invention is not limited to this, but instead of the chain,
The same effect can be obtained by using a timing belt, a chain belt, or the like. Moreover, although the example applied to the cylindrical pipes 1A and 1B of the feed water heater as the object to be welded is shown, it can be similarly used when welding the cylindrical bodies to each other. Of course, it can be certainly applied.

[0039]

As described above, claims 1 to 5 of the present invention.
According to 3, when the guide / holding body is wound around the outer periphery of one of the objects to be welded, the guide / holding body engages with the traveling carriage, so that the traveling carriage is sandwiched so as to be able to travel on the outer periphery of the workpiece. In addition, since the traveling carriage is configured to be guided along the welding line portion, even if the traveling carriage and the welding head portion mounted on the traveling carriage are heavy, the traveling carriage may fall from the cylindrical pipe. As a result, the traveling carriage can be reliably driven along the outer circumference of the work piece to be welded, so that the installation work of the device can be performed easily and safely, and even if the diameter of the work piece is different, it can be adjusted accordingly. It is not necessary to manufacture it one by one, and further, it is possible to reliably prevent the traveling carriage from dropping, and therefore, there is an effect that ease of installation and production and reliability during traveling can be obtained.

In particular, according to the second aspect, since the traveling carriage has the electromagnetic wheels that roll while adsorbing to the object to be welded, the driving means for the traveling wheels, and the rotating body that engages with the guide / holding body, the electromagnetic wheels can be used. Due to the attraction force of the wheels and the gripping force between the guide / holding body, the traveling carriage can be made to reliably travel on the outer periphery of the object to be welded, and the traveling reliability can be improved.
According to the third aspect of the present invention, since the tensioner can adjust the tightening force of the traveling carriage with respect to the object to be welded so that the traveling carriage can travel on the object to be welded, the traveling carriage on the object to be welded can be adjusted. Also, there is an effect that the holder that also serves as a guide can be easily attached.

[Brief description of drawings]

FIG. 1 is a schematic perspective view for explanation in which an automatic welding device according to the present invention is applied to a cylindrical pipe of a feed water heater.

FIG. 2 is a sectional side view (a) and a plan view (b) for explaining a traveling carriage of the automatic welding device.

FIG. 3 is a perspective view showing a welding head portion and a welding power source side mounted on a traveling carriage.

FIG. 4 is an explanatory view showing a main part of a guide / holding body.

FIG. 5 is a perspective view showing an example of a conventional technique.

6 is a cross-sectional explanatory view showing the main part of FIG.

FIG. 7 is a perspective view showing another example of the prior art.

[Explanation of symbols]

1A, 1B ... Cylindrical tube, 2 ... Welding line part, 3 ... Traveling carriage, 4
... A holder also serving as a guide, 5 ... Electromagnetic wheels, 6 to 10 ... Driving means, 11 ... Sprocket, 15 ... Tensioner, 20 ...
Welding head part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hide Takahashi 3-1-1, Sachimachi, Hitachi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor, Koji Hara 3-chome, Sachimachi, Hitachi, Ibaraki No. 1 Hitachi Ltd., Hitachi Plant (72) Inventor Yuu Araya 3-1-1, Saiwaicho, Hitachi City, Ibaraki Hitachi Ltd., Hitachi Plant

Claims (3)

[Claims] 1. Automatic welding for welding the welding line portions of the cylindrical workpieces, which are made of a magnetic material, and run along the outer periphery of one of the workpieces when the workpieces are welded to each other. In the device, a traveling carriage that can travel on the outer circumference of the work piece while being attracted to the outer circumference of the one work piece, and a traveling carriage that is wound around the outer circumference of the one work piece along the welding line portion. A guide / holding member for guiding the traveling of the traveling vehicle along the welding line portion and also sandwiching the traveling vehicle so that the traveling vehicle can travel on the outer periphery of the object to be welded; and a welding head portion mounted on the traveling vehicle for welding the welding line portion. The holding member that also serves as a guide has a long string shape in which one end of the holding member is inserted through the traveling carriage and is wound around the outer periphery of the object to be welded and fastened to the other end when attached to the object to be welded. An automatic welding device characterized in that 2. Automatic welding for welding welded line parts of a cylindrical columnar work made of a magnetic material, which run along the outer periphery of one work to be welded when the work is welded to each other. In the device, a traveling carriage that can travel on the outer circumference of the work piece while being attracted to the outer circumference of the one work piece, and a traveling carriage that is wound around the outer circumference of the one work piece along the welding line portion. A guide / holding member for guiding the traveling of the traveling vehicle along the welding line portion and also sandwiching the traveling vehicle so that the traveling vehicle can travel on the outer periphery of the object to be welded; and a welding head portion mounted on the traveling vehicle for welding the welding line portion. The traveling carriage is attracted to the outer periphery of the work piece by magnetic force, and in the state where it is attracted, electromagnetic wheels that roll on the outer periphery of the work piece while rotating, and drive means for driving the electromagnetic wheel When,
A rotating body that is rotatably supported and that engages with a guide / holding body to guide the travel of the traveling carriage. One end of the guide / holding body is mounted on the workpiece to be welded. The automatic welding device is characterized in that it is in the form of a long string that is inserted through and wound around the outer periphery of the object to be welded and is fastened to the other end side. 3. Automatic welding for welding, when two cylindrical objects to be welded made of a magnetic material are butted against each other, traveling along the outer periphery of one of the objects to be welded and welding the weld line parts of the objects to be butted to each other. In the device, a traveling carriage that can travel on the outer circumference of the work piece while being attracted to the outer circumference of the one work piece, and a traveling carriage that is wound around the outer circumference of the one work piece along the welding line portion. A guide / holding member for guiding the traveling of the traveling vehicle along the welding line portion and also sandwiching the traveling vehicle so that the traveling vehicle can travel on the outer periphery of the object to be welded; and a welding head portion mounted on the traveling vehicle for welding the welding line portion. The traveling cart is attracted to the outer periphery of the object to be welded by magnetic force, and in the state of being attracted, the traveling wheel drives the electromagnetic wheel that rolls on the outer periphery of the object to be welded while being rotated by the drive means. Drive means to rotate, A rotating body that is supported at the same time and that guides the traveling of the traveling carriage by engaging with the guide-carrying holding body. It has a long string shape that is inserted and wound around the outer periphery of the object to be welded and fastened to the other end side, and the guide / holding body provides a tension that allows the traveling carriage to be sandwiched so as to be able to travel on the outer periphery of the object to be welded. An automatic welding device having a tensioner.