JPH02127975A - Automatic pipe inner welding equipment - Google Patents

Abstract

PURPOSE:To perform optimum welding in accordance with a groove shape of a weld zone by providing a welding torch inclination part to support the axis center of the welding torch tiltably in the pipe-axial direction with a weld line as a center in a state with the welding torch faced on the weld line. CONSTITUTION:When an inclined motor 51 is driven and a shaft 50 is rotated normally and reversely in the range by 90 deg., the torch 5 supported by a supporting tool 54 is inclined in the range by 45 deg. in the pipe-axial direction with the weld line as a center. In this case, since it is arranged that an extension line of the axis center of the torch 5 and an extension line of the shaft 50 cross each other even if the torch 5 is inclined, the torch 5 is made in a state to front the weld line at all times and an arc is not deviated from above the weld line. By this method, it also meets fillet welding accurately and easily.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to welding from the inner surface, for example, when repairing cracks in pipes buried in underground pipes or defective joints by welding. This invention relates to automatic welding equipment that performs.

[Prior art]

BACKGROUND ART When a pipeline for transporting gas or liquid buried underground becomes obsolete, it is required to repair it in its original state.

This repair work can be done by excavating the ground and removing the outside surface of the pipe, but in many cases excavation is not possible due to circumstances on the pipe.
It can be said that a more rational method is to do it from the inside of the pipe.

Now, the most important repair work inside this pipe is welding work. Semi-automatic welding machines for use inside large-diameter pipes include a semi-automatic type in which a worker enters the pipe together with the welding machine and performs welding while changing control conditions.

However, for medium and small diameter pipes with an inner diameter of 800 mm or less, it is impossible for workers to enter the pipe for safety reasons.

Therefore, an automatic welding machine that can be moved freely to the desired position inside the pipe and can be precisely controlled from outside the pipe is needed.
For example, there is one disclosed in Japanese Utility Model Application Publication No. 59-20992.

[Problem to be solved by the invention]

By the way, most conventional automatic welding machines are designed for the installation of new large-diameter pipes. In addition, even those for small and medium diameter pipes are designed to pass through straight sections, and are designed to be able to bypass existing pipes, that is, other structures, or move within three-dimensional pipes that follow the topography of mountains and valleys. It has not been.

In other words, existing pipelines have sections with different diameters using various joints such as flanges and dresser couplings, but it is difficult to pass them smoothly, and welding at inclined and vertical sections is difficult. Can not. Furthermore, when welding is performed not only on inclined and vertical parts but also on horizontal parts, it is necessary to fix the welding machine inside the pipe. As this fixing means, a configuration in which a plurality of hydraulic or pneumatic jacks are generally arranged radially with respect to the welding machine is considered.
With this configuration, it is difficult to synchronize the extension amount of each jack, and for this reason, the central axis of the welding machine, that is, the rotation axis of the welding torch, which performs full-circumference welding by rotating in the circumferential direction, is difficult to synchronize. It is not possible to accurately match the pipe axis, resulting in a decrease in welding accuracy. In addition, when moving inside the pipe, it is necessary to equip jacks to prevent contact with the inner surface of the pipe at the curved part, and the amount of jacks used is limited by the amount of gap between the welding machine body and the inner surface of the pipe, so There also arises a problem that sufficient fixing force cannot be obtained.

Furthermore, an important point when welding the inner surface of an existing pipe is to perform welding that adapts to the groove shape of the weld.

For example, in a sleeve-type joint, both pipes that are butted together are separated from each other within the joint, and the welding of the stepped portion between the pipe and the joint corresponds to fillet welding. However, with conventional welding machines, the axis of the welding torch is fixed in the radial direction of the pipe, so it is not possible to efficiently handle fillet welding, and it is necessary to perform multiple welds by moving the torch in the direction of the pipe axis. In addition, the appearance of the weld bead was not good.

The present invention has been made in view of such circumstances, and is based on the pipe construction method proposed by the applicant (Japanese Patent Laid-Open No. 63-158).
386 Publication), it can be moved freely even in existing pipes that have different diameter parts, and the main body can be accurately and reliably fixed at the pipe axis position during welding, and can be adjusted according to the groove shape of the welded part. The purpose of the present invention is to provide an automatic pipe inner welding device that enables optimal welding.

[Means to solve the problem]

The automatic welding device for the inner surface of a tube according to the present invention includes a welding machine that is connected to a traveling machine, travels within the pipeline, and rotates a welding torch in the circumferential direction of the tube in a stopped state to weld the entire circumference of the inner surface of the tube. In the automatic tube inner surface welding apparatus, the welding machine includes a plurality of track-type running sections disposed at the tip and rolling in contact with the inner surface of the tube, and track-type running sections that are equally distributed in the circumferential direction and stand up in the radial direction to weld the inside of the tube. a plurality of arms pivotally supported so as to be able to come into contact with a surface; a piston cylinder connected to the arms and fitted onto the body with its axis in the front-rear direction of the body for raising and lowering the arms; and the piston. A cylinder section that is fitted onto a cylinder and fixed to the fuselage, and that includes a cylinder tube that forms an annular cylinder chamber between the piston cylinder and the piston cylinder for moving the piston cylinder in the longitudinal direction of the aircraft body, and the welding torch is connected to the welding target. The welding torch is characterized by comprising a welding torch inclined part that supports the axis of the welding torch so as to be tiltable in the tube axis direction around the welded line in a state facing the welding line.

[Effect]

The welding machine is driven by a traveling machine and travels within the pipe, with the inner surface of the pipe and the track-type traveling section in contact with each other.

When stopping, the cylinder section is driven and the piston tube is moved in the front-rear direction of the aircraft, so that the multiple arms connected to the piston tube stand up in synchronization in the radial direction and come into contact with the inner surface of the tube. Ru. As a result, the welding machine is fixedly supported at the axial center position of the tube.

The welding torch, which is rotated in the circumferential direction, is supported by the welding torch inclined portion so as to be tiltable in the tube axis direction about the welding line, with the torch facing the welding line.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof. First, the automatic tube inner welding device according to the present invention has the following features:
As mentioned above, it is designed to be incorporated into a device for implementing the pipe construction method proposed by the present applicant. Fig. 11 is a schematic diagram of the structure, and pits P+ and Pt are built at both ends of the existing pipe line (hereinafter referred to as pipe line) S that is buried underground and is the target of repair welding. A guide rope R is stretched between the winches W, , W, which are installed separately in the pipe. Each working device constitutes one working unit, which moves in the pipe along a guide rope R, and the working units are, for example, in order from the front: a spherical guide trolley AI, a welding trolley B, which is the welding machine. , a cart cart C2 equipped with welding wire etc. to be supplied to the welding truck B; a traction cart which is a traveling machine that generates traction force for moving the working unit into the pipe; and a guide cart A2 having the same configuration as the guide cart A1. has been done. Each truck has a guide rope R inserted through its axis, and is connected at intervals so that each truck can pass through a curved pipe section with the maximum turning angle and minimum curvature in the conduit S. For the connection, a hollow ball joint is used instead of an ordinary universal joint, and the guide rope R is inserted through the hollow part.

If a universal joint is used, not only will the guide rope R not be able to be inserted, but the guide rope R will be bent more than necessary at the bend, and the traction force of the towing trolley will no longer work in the forward direction of the trolley, causing the trolley to become jammed. In order to prevent this problem, a stopper is formed on the ball joint to limit the bending range.

For example, the tow truck has a built-in cab ski winch, and a guide rope R is connected to the drum driven by the winch.
By winding the drum several times and rotating the drum while maintaining the frictional force, a traction force is generated on the guide rope R, and the reaction force causes the drum to move itself.

As a result, each truck connected to the towing truck, that is, the work unit, can freely move within the conduit S.

Guide carts A+ and At are connected between them.

The guide rope R is provided to position the guide rope R at the axis of the pipe so that the work cart can smoothly pass through the curved pipe section.In addition, for the front guide cart A, the repair welding area is placed outside the pipe. The rear guide cart A2 is equipped with a potentiometer that detects the amount of travel along the guide rope R in order to detect the travel distance.

With the device configuration as described above, the work unit including the welding cart B is moved to a required position within the pipe line S to perform welding. Next, the welding cart B according to the present invention will be explained.

1 and 2 are a side sectional view and a front view of the welding cart. The welding cart B has the guide rope R at its axial center position.
A guide rope insertion tube 1 is arranged at the front end of which the guide rope is inserted, and a bendable connecting tube 1c is connected to the guide trolley A1 at the front end of the guide rope insertion tube 1.
In addition, a hollow ball joint (not shown) to be connected to the following cart C is fitted onto the rear end of the cart.

An inner tube 2 and an outer tube 3 having circular circumferential surfaces are fitted coaxially with the guide rope insertion tube 1, and a welding head 4 is provided on the tip side of the inner tube 2. The inner tube 2 has face plates 201 and 202 at both ends, and the guide rope insertion tube 1 is pivotally supported by bearings 1a and lb provided in the center of these, and the welding head 4 is provided inside in the axial direction and in the tube axis direction. A drive mechanism for radial movement is provided. The inner cylinder 2 and the outer cylinder 3 are mutually supported by, for example, cross roller bearings 301 and 302 provided at both ends, and by rotating the inner cylinder 2 with respect to the outer cylinder 3, the welding head 4 can be rotated around the circumference. It is designed to weld the entire circumference of the inner surface of the tube by moving it in the direction of the tube.

The outer tube 3 is equipped with running parts 8 and 9 that come into contact with the inner surface of the tube when moving inside the tube, and a clamp mechanism 10 for fixing the welding cart inside the tube when welding, on the outer peripheral surface, respectively. The running parts 8 and 9 are located near both ends of the circumferential surface of the outer cylinder 3 at six equally spaced positions, and the clamp arm 11 that contacts the inner surface of the tube in the clamp mechanism 10 is located at three equally spaced positions different from the positions of the running parts. They are also provided near both ends of the same position. FIG. 3 is an enlarged side cross-sectional view of the clamp mechanism 10 and the traveling section, and the clamp mechanism 10 operates the clamp arm 11 with the air cylinder 101, which is the annular cylinder section fitted onto the center of the outer cylinder 3. The air cylinder 101 has a piston 103 disposed around the outer circumferential surface of the central part of the air cylinder 101, and a piston cylinder 102 that is loosely fitted into the outer cylinder 3. A cylinder tube 104, which hermetically seals the piston 103 to form a cylinder chamber so as to be movable in the tube axis direction, is attached to the piston tube 1.
A plurality of fixtures 105, 105.
It is attached to the outer cylinder 3 by... The cylinder tube 104 has compressed air intake and exhaust holes 10 at both ends thereof.
6a and 106b are provided.

There are six clamp arms 11 in total, three in the front and three in the front, and the ends of the clamp arms that come into contact with the inner circumferential surface of the pipe S are directed forward, that is, in the radial direction of the pipe, in the direction of movement of the truck. It is pivoted by a support 111 fixed to the outer cylinder 3 near the middle part so that it can be raised up and down from the outer cylinder 3. Further, the base ends of these clamp arms 11 and the front and rear ends of the piston cylinder 102 are connected by links 112 and 113, respectively. In other words, when the piston cylinder 102 is extended forward, as shown in FIG.
1 stands up synchronously from the outer cylinder 3 and comes into contact with the inner circumferential surface of the pipe S. As a result, the cart is placed inside the pipe S.
The axial center of the truck and the axial center of the conduit S are fixed in the same state. Furthermore, when the piston cylinder 102 is extended rearward, all the clamp arms 11 are collapsed toward the outer cylinder 3 side as shown in FIG. This makes it easier to pass through.

In this way, the clamp mechanism 10 is configured such that the outer cylinder 3, that is, the welding machine main body, is inserted through the piston of the air cylinder, so that the outer cylinder 3, that is, the welding machine main body, can be inserted into the piston of the air cylinder. 3, and by appropriately designing the piston cross section and cylinder chamber capacity,
A large fixing force can be applied to the clamp arm 11.

Note that a hydraulic cylinder may be used in place of the air cylinder, but since it moves over a long distance within the pipe, it is preferable to use pneumatic pressure that can easily supply pressurized fluid from outside the pipe.

Next, the running section has different forms on the front side and the rear side, and first, the crawler type running section 6 is provided on the front side.
The running section 8 is made up of two wheels 84 arranged in parallel in the front and back, with their axes separated by an appropriate length in a direction parallel to the axial direction of the outer cylinder 3.
．． The wheels 84 and 84 are pivotally supported by a wheel support member 83, and the wheel support member 83 is attached to the outer cylinder 3 with a support 81. The height of the protrusion of the running portion 8 from the outer cylinder 3 is higher than when the clamp arm 11 is folded down, and lower than when the clamp arm 11 is upright. A running belt 85 made of an elastic material is wound between the front and rear wheels 84, 84, and the running section 8 runs with the running belt 85 in contact with the inner surface of the tube. This makes it easier to pass through misaligned parts and stepped parts compared to the case of using only ordinary wheels, and it also prevents damage to the inner surface of the tube.

On the other hand, the same six running parts 9 provided on the rear side of the outer cylinder 3 via the air cylinder 101 also support the wheels 92 in the axial length direction of the outer cylinder 3 by means of supports 91 attached to the outer cylinder 3. The wheels 92 are similarly made of resin so as not to damage the inner surface of the tube. The height of each running section 9 protruding from the outer cylinder 3 is lower than that of the running section 8. The distance in the pipe axis direction and the outer diameter of the running parts 8 and 9 are determined by the curved pipe part in the conduit S (-as an example, the dashed line B) It is designed and specified so that it can pass through.

In addition, when passing through a substantially horizontal straight section in the conduit S, the bogie will move as shown by the two-dot chain line A (traveling section 8
The running belt 85 in the rear wheel portion and the running part 9
It comes into contact with the inside of the pipe by the wheels 92 and travels in a state where the front is curved. This is because the front and rear wheels 84,84 of the running section 8 are fixed parallel to the axial direction of the outer cylinder 3, and as a result, the running belt 85 at the front wheel portion of the running section 8
Since it travels in a state where it is slightly lifted from the inner surface of the tube, it is possible to more easily get over even the uphill step where there is a considerable difference in height. Furthermore, immediately after the running section 8 passes through such a step, there is a possibility that the air cylinder 101 will come into contact with the step and hinder the running; Part 8
Since gutter members 107 each having a gently curved surface extending in the length direction of the cylinder tube 104 are attached at positions between 9 and 9, the ⃰∆ member 107 slides on the stepped portion to prevent running. is not hindered.

4 is a sectional view taken along the line IV-IV in FIG. 1, and a rack 31 is provided around the inner surface of the outer cylinder 3.
protrudes from an opening provided on the circumferential surface of the inner cylinder 2 and meshes with a gear 221 to which the driving force of a swing motor 21 (see FIG. 1) provided within the inner cylinder 2 is transmitted. The swing motor 21 is mounted above the guide rope insertion tube 1 in the inner tube 2 (
The state shown in the figure is the basic posture), and the rotary shaft is mounted on a pedestal 203 that is mounted parallel to the radial direction at a position near the front with the rotary shaft facing rearward. Reducer 2 mounted on the rear coaxially via 210
The gear 221 is connected to the input shaft of the speed reducer 22, and the gear 221 is fitted and fixed to the output shaft of the speed reducer 22. A tachometer generator 212 is attached to the left side of the shaft joint 210, and the tachometer generator 212 detects the rotational speed of the swing motor 21 via a belt 211 that is hung between the tachometer generator 212 and the shaft joint 210. In other words, in the inner cylinder 2 that is fitted into the outer cylinder 3 via the cross roller bearings 301 and 302, with the outer cylinder 3 fixed in the pipe line by the clamp mechanism 10,
When the swing motor 21 is driven and the gear 221 is rotated, the inner cylinder 2 is rotated in the circumferential direction with respect to the outer cylinder 3.

A rotary potentiometer 204 is attached to the lower surface of the pedestal 203 with a part thereof protruding from an opening provided on the circumferential surface of the inner cylinder 2 by means of a support 206, with the axial length direction being the tube axis direction, A gear 205 is fitted to the detection shaft of the potentiometer 204, and the gear 205 is meshed with the rack 31 of the outer cylinder 3. Thereby, the rotational position of the inner cylinder 2 with respect to the outer cylinder 3 is detected.

A rotary potentiometer 32 is installed at a position slightly behind the rack 31 of the outer cylinder 3, with its axial length direction being the tube axis direction, and the potentiometer 32 has a gear 33 fitted on its detection shaft. It is configured to mesh with a rack 207 formed on a part of the outer peripheral surface of the inner cylinder 2 in the circumferential direction. That is, the gear 33 of the potentiometer 32 is connected to the rack 2.
07 and is rotated by the number of teeth of the rack 207, a signal is output only when the rack 207 is rotated by the number of teeth of the rack 207, thereby detecting the rotation speed of the inner cylinder 2 with respect to the outer cylinder 3.

At the rear of the reducer 22 including the gear 221, there is a 10th
Pendulum type potentiometer 2 as shown in the external perspective view of the figure.
08a is attached to the inner peripheral surface of the inner cylinder 2. The potentiometer 208a is the rotary shaft 2
08b, and detects the amount of rotation of the rotating shaft 208b, and a weight 208c attached to the end of the rotating shaft 208b protruding to one side in the radial direction detects the rotation of the rotating shaft 208b in a horizontal state. is held in the direction of gravity. Further, the outer frame portion of the potentiometer 208a is fixed to an intermediate portion of a rolling shaft 208f in a direction orthogonal to the rotating shaft 208b, and both ends of the rolling shaft 208f are pivotally supported by a support member 208e. In other words, the potentiometer 208a is rotatably supported around a rolling shaft 208f, and a weight 208c is balanced at the end of the potentiometer 208a on the side from which the rotating ring 208b is not projected. A balance weight 208d is provided for this purpose. The support member 208e supports the rotating shaft 208b of the weight 208c.
The rolling shaft 208f is supported at intervals so as to enable both rotation around the rolling shaft 208f of the potentiometer 208a including the weight 208c and the balance weight 208d,
The shaft 208f is attached to the inner peripheral surface of the inner cylinder 2 with the axial direction of the shaft 208f being the axial direction of the inner cylinder 2.

In the posture detector 208 configured in this way, the potentiometer 208a is set to the rolling axis 2 no matter what rolling angle the welding cart B in the pipe S is at.
08f, the rotation axis 208b of the potentiometer 208a is always held in the horizontal direction orthogonal to the tube axis direction. When the conduit S is inclined, the rotating shaft 208b is rotated by the amount of inclination of the rolling shaft 208f from the horizontal state by the action of the weight 208c, and this rotation amount is the inclination of the conduit S, that is, the welding This is detected as the attitude of truck B. Here potentiometer 2
As 08a, for example, PMP-45U manufactured by Midori Sokki can be used.

The attitude of the welding cart B detected in this way is one of the important factors in performing welding. In other words, when welding cart B is in a vertical state, the direction of gravity of the torch during welding all around is constant, but when it is in a horizontal state, it changes every moment.
It is not preferable to apply the same welding conditions to both of these. Therefore, the inclination of the pipe is detected and welding is performed under welding conditions that are adapted to the inclination.

A posture detector 209 (see FIG. 13) having the same structure as the posture detector 208 is located at a different position in the circumferential direction on the inner circumferential surface of the inner cylinder 2 to which the posture detector 208 is attached. It is installed with its longitudinal direction perpendicular to the axial direction of the inner cylinder 2. The posture detector 209 is provided to align the base point of the torch 5 with the direction of gravity during full circumference welding. That is, in this embodiment, the arc start position for welding is set at 6 o'clock in the direction of gravity, that is, in the circumferential direction, and by starting welding all around the circumference from this position,
The position of the part to be welded can be determined from the amount of rotation (cumulative angle) of the inner cylinder 2 detected by the potentiometer 204, and appropriate welding conditions can be commanded for each position. For this reason, the arc start position can be set in the direction of gravity by recognizing in advance the output value of the attitude detector 209 when the torch 5 is in the direction of gravity, and rotating the inner cylinder 2 so as to indicate this value. .

A welding wire (not shown) delivery hole is provided in the face plate 201 on the front side of the inner cylinder 2, and a wire supply motor 23 for this purpose is attached to the inner surface of this hole.

The welding wire is wound around a drum and equipped in the following cart C, and is passed from an inlet hole (not shown) provided in a face plate 202 on the rear side of the inner cylinder 2 to a wire supply motor 23 inside the inner cylinder 2. being sent. This feeding hole is provided with a roller that rotates in contact with the welding wire, and a tacho generator 231 (see Fig. 13) attached to this roller detects the feeding speed of the welding wire by the wire feeding motor 23. It has become.

A drive unit 24 for moving the welding head 4 in the tube axis and radial directions is provided at the bottom of the inner cylinder 2, that is, at the opposite side to the part where the swing motor 21 and the like are disposed.

FIG. 5 is a plan cross-sectional view of the drive unit 24, in which a flat box-shaped casing 240 has slide guide bases 24 disposed in parallel on both sides of the casing 240 at an appropriate distance apart.
1 and 242, the bottom of the casing 240 is attached to the inner peripheral surface of the inner cylinder 2 with the longitudinal direction of the casing 242 being the axial direction of the inner cylinder 2. Slide guide base 241, 242
are engaged with both sides of a slide base 29, and the slide base 29 moves inside the casing 240 with the slide guide base 24.
1,242 in the axial direction of the inner cylinder 2. A cylindrical welding head shaft 27b protrudes from the front wall of the casing 240 and the face plate 201 of the inner cylinder 2 at the front of the sliding table 29, with the axial direction of the shaft 27b extending in the sliding direction of the sliding table 29. The welding head shaft 27b is attached to the inner cylinder 2.
The inside of the outer cylinder 3 is communicated with a gear box 7 located in front of the outer cylinder 3, and the tip end thereof is fixed. The sliding table 29 also includes a gear chamber 243 provided at the rear of the casing 240.
A spline shaft 27 and a ball screw shaft 28, which respectively protrude into the casing 240, are inserted into the spline shaft 27 and the ball screw shaft 28, respectively. These shafts 27 and 28 are slightly shorter than the slide guide base, and each forms a spline and a screw groove over the entire length inside the casing 240, and the length direction of these shafts is an appropriate length as the sliding direction of the slide table 29. The spline shaft 27 is inserted into a hollow drive shaft 27a which is coaxially inserted into the welding head shaft 27b.

The drive shaft 27a has its tip protruding into the gear box 7, and its rear end positioned at the rear of the sliding table 29, and its movement in the axial direction is restricted by a bearing, and the welding head shaft 27b It is rotatable within the sliding table 29, and is spline-coupled to the spline shaft 27 at its rear end.

On the other hand, the ball screw shaft 28 is screwed into a screw nut 281 fixed in the slide table 29, and the ball screw shaft 28 is screwed into the slide table 29.
It is inserted through.

The spline shaft 27 and the ball screw shaft 28 have their ends within the gear chamber 243 to which the driving forces of the radial movement motor 25 and tube axial movement motor 26, which are respectively attached to the rear side of the gear chamber 243, are transmitted. It is rotated by this.

The radial direction movement motor 25 and the tube axial direction movement motor 26 are
The respective rotating shafts are taken out on both sides, one of the rotating shafts is inserted into the gear chamber 243, and the other is inserted into the shaft coupling 25.
1 and 261 are installed, reducers 252 and 262
It is connected to the input shaft of. Rotary potentiometers 253 and 263 (
(see FIG. 13) are connected. In addition, each shaft joint 25
1 and 261 are equipped with a belt 211 and a tacho generator 212 (not shown) for detecting the rotational speed of the swing motor 21, so as to detect the rotational speed.

A gear 271 is fitted to the tip of the drive shaft 27a that is inserted into the gear box 7. A gear 72 fitted into an intermediate portion of a pinion shaft 71 that is supported in the direction is meshed with each other. A rack 74, which is located in front of the pinion gear 73 provided at one end of the pinion shaft 71 and is fixed to a sliding member 75 with its longitudinal direction perpendicular to the pinion shaft 71 in the vertical direction, is meshed with the pinion gear 73. It's Nishide. The sliding member 75 is configured to be slid by engaging with a slide guide base 76 that is attached to the inner surface of the gear box 7 with the sliding direction being vertical. of,
A long guide hole 77 formed in the front wall of the gear box 7 to accommodate the sliding range of the sliding member 75 is inserted into and protrudes from the front wall of the gear box 7, and a head plate serving as a base plate of the welding head 4 is inserted into this part. 41 is the installation.

That is, when moving the welding head 4 in the radial direction, the drive unit 24 rotates the spline shaft 27 by driving the radial movement motor 25. The rotation of the spline shaft 27 is transmitted to the drive shaft 27a and then to the pinion shaft 71. Then, the rotation of the pinion shaft 71 is converted into a linear motion by the rack 74, and the sliding member 75 is slid on the slide guide base 76 in a direction corresponding to the rotational direction of the motor, and the head plate 41 attached thereto is By being moved, the welding rod 4 is moved in the radial direction. The radial position of this welding rod 4 is zero so that it can be detected by the potentiometer 253.

On the other hand, when moving the welding head 4 in the tube axis direction, the tube axis direction movement motor 26 is driven to rotate the ball screw shaft 28. Then, since the screw nut 281 screwed onto the ball screw shaft 28 is fixed to the sliding base 29, the sliding base 29 is moved above the slide guide base 241, 242 by an amount corresponding to the amount of rotation of the ball screw shaft 28. is slid. As a result, the welding head shaft 27b attached to the sliding table 29 is moved in the tube axis direction, and the welding head 4 attached to the tip portion together with the gear box 7 is moved in the tube axis direction. This makes it possible to live. The position of the welding rod 4 in the tube axis direction is detected by the potentiometer 263. Further, in this case, the drive shaft 27a is the welding head shaft 27b.
However, since the drive shaft 27, that is, the welding head 4, is moved in the tube axis direction, it is spline-coupled with the spline shaft 27, which is fixed in the axial direction. The driving force of the radial movement motor 25 can be transmitted to the drive shaft 27a, so that it is possible to drive both motors simultaneously to move the rad 4 toward welding.

Now, next, the welding head 4 will be explained. FIG. 6 and FIG. 7 are a front view and a side view, respectively, of the welding head showing the state during welding. The welding head 4, which is constructed on the front part of the head plate 41 as a substrate, is equipped with a torch 5 on one side in the radial direction and a welding line copying device 6 on the other side, and the welding head 4 is provided with a welding line tracing device 6 on the other side in the radial direction. The initial setting position is achieved by moving the head plate 41 closer to the inner surface of the tube by driving the radial movement motor 25. The torch 5 is set with its axis located on the same plane that includes the diameter line of the inner cylinder 2, and in this state, that is, with the line to be welded facing, the tube axis is aligned with the line to be welded. The tilting motor 5 is configured to be tiltable in 45-degree increments in the direction, and this tilting operation is performed by a tilting motor 5 whose drive shaft is located parallel to the radial direction and is located near the axial center of the inner cylinder 2 in the head plate 41.
1 is scheduled to take place. The drive shaft of the tilt angle motor 51 is connected via a universal joint 52 to a shaft 50 which is disposed at a 45 degree inclination to the drive shaft at a bearing stand 53.
The support 54 of the torch 5 is attached at the initial setting position so that the extension line of the axis of the torch 5 intersects the extension line of the shaft 50 on the line to be welded. The universal joint 52 is used because the mounting position of the tilt angle motor 51 can be set freely, and by arranging it near the center, the motor is prevented from coming into contact with the inner surface of the tube.

The welding torch inclined portion has such a configuration, and when the inclination motor 51 is driven and the shaft 50 is reversed in the normal direction within a range of 90 degrees, the torch 5 supported by the support 54 moves along the broken line in FIG. As shown in the figure, the tube is inclined within a range of 45 degrees in the tube axis direction with the line to be welded as the center. In this case, torch 5
Even if the torch 5 is tilted, the extension line of the axis of the torch 5 and the extension line of the shaft 50 will not intersect, so the torch 5 will always face the line to be welded and the arc will not come off the line to be welded. There isn't. This allows fillet welding to be handled accurately and easily. A pulse motor is used as the inclination motor 51, and by changing the output value of the pulse signal, the inclination angle of the torch 5 can be set according to the part to be welded.

55a and 55b are TV cameras for arc monitoring, respectively, and the support 54 of the torch 5 and the head plate 41, respectively.
The camera is supported symmetrically in the circumferential direction via the torch 5 by camera supports 550 and 551 attached to the camera support members 550 and 551, so as to face the part to be welded and the periphery of the tip of the torch 5.

One of the TV cameras 55a and 55b is used depending on the circumferential direction in which welding is performed, and the torch 5
A TV camera located upstream in the direction of rotation is used.

These TV cameras use a CCD camera, and in order to reduce the size and weight and improve the visibility of the arc produced by MAG welding, images are not transmitted to the camera using an image fiber as in the past, but a direct open/close type. The arc is imaged through a filter 552. This filter 5
52 is opened and closed using a solenoid, for example,
In the open state, the state of the torch 5 before arc generation can be observed. Furthermore, while it is difficult to observe the welded part such as a groove while an arc is occurring, by adding a motor-driven aperture mechanism to the camera, it is possible to observe the position of the arc light when the aperture is narrowed down. When the aperture is opened, the part to be welded can be observed.

When the truck travels within the pipeline, the welding head 4 moves the head plate 41 toward the axis of the truck, as shown in the side view of FIG. 8. This prevents the torch 5 and copying device 6 from coming into contact with the inner surface of the tube.

The copying device 6 includes sensors 60.60 using direct-acting potentiometers 61.62. The air cylinder 63 is equipped with a TV camera 66 and an air cylinder 63, and the air cylinder 63 has an axial direction parallel to the radial direction of the inner cylinder 2 on the side of the connecting cylinder 1c with a cylinder support 64 attached to the head plate 41. Position and support. A sensor support 65 that supports the sensor 60 is attached to the tip of the piston rod of the air cylinder 63, and the sensor support 65 is a flat plate portion bent from the tip of the piston loft to the proximal end in parallel with the piston rod. The sensor 60 is attached to this flat plate portion. This is to make the entire air cylinder 63 compact while using one with as long a stroke as possible.

Each potentiometer 61, 62 of the sensor 60 is provided with a contact 610, 620 that contacts the inner surface of the tube at the tip of a shaft that is biased and protrudes outward from the cylindrical main body so as to be movable in the axial direction. The amount of movement of each shaft into and out of the main body when each shaft is pressed is detected, and the axial direction of each shaft is the axial direction of the air cylinder 63, and the tip of each main body is The connecting cylinder 1c of the flat plate part of the sensor support 65 is aligned so that the tip of the cylinder 63 and the road surface are aligned.
It is installed on the side of the inner cylinder 2 at an appropriate distance in the axial direction. The mounting positions of the potentiometers 61 and 62 in the tube axis direction are as shown in FIG.
As shown in the side view seen from side c, they are spaced apart by equal lengths in the tube axis direction across the axis of the torch 5.

The TV camera 66 uses a support 661 attached to the gear box 7 to align the center of its imaging range on a plane that includes the axial center line of the torch 5 and is orthogonal to the axial direction of the inner cylinder 2, and then each potentiometer 61 It is fixed at a position that does not impede these movements on the sides of 62°.

The procedure for using the copying device 6 configured in this way is to first move the welding cart B to a position in front of the part to be welded (then move the welding cart B to a position in front of the welded part).
The welding head 4 protruded from the pipe is fixed in the pipe at a position where it can move sufficiently in the pipe axial direction centering on the part to be welded, and then the pipe axial movement motor 26 is driven to move the welding head 4 into the pipe. It is caused to protrude in the axial direction and stopped when the imaging center of the TV camera 66 coincides with the line to be welded. This is TV1 for monitoring the TV camera 66 installed outside the pipe, which will be described later.
The welding is performed by matching the captured image of the welding line with a fixed point formed on the screen of 6 (see FIG. The distance from the truck B to the line to be welded in the tube axis direction can be calculated.

When this is completed, the sensor support 65 is brought closer to the inner surface of the tube by operating the air cylinder 63 to extend the piston rod by the maximum amount. In this state, each potentiometer 61 of the sensor 60 is moved by driving the radial movement motor 25 to move the head plate 41.
．． The contacts 610 and 620 at 62 are brought into contact with the inner surface of the tube. As a result, the shaft with each contact is housed in the main body of each potentiometer, and when each potentiometer outputs a constant value, the radial movement motor 2
5 is stopped. This stop position is the initial setting position of the copying device 6, and each potentiometer has a contact in contact with both tubes to be welded. Further, the distance from the center of the welding cart B to the inner surface of the tube can be calculated from the output value of the potentiometer 253 at this time, that is, the amount of rotation of the radial movement motor 25.

Now, when the above operations are completed, the swing motor 21 is operated in order to continuously obtain the tracing data of the welded part over the entire circumference.
is driven to rotate the inner cylinder 2 in a clockwise direction when viewed from the front.

During this rotation, the operator drives the tube axis direction movement motor 26 to move the welding head 4 in the tube axis direction so that the image of the line to be welded always matches a fixed point on the screen of the TV 16. Since this amount of movement is detected by the potentiometer 263, data on the welded portion in the tube axis direction can be obtained.

During this rotation, the radial movement motor 25 is automatically controlled and driven so that the detected value of the rear potentiometer 62 of the sensor 60 becomes a constant value, and the welding head 4 is also moved in the radial direction. This amount of movement is determined by potentiometer 2.
53, it is possible to obtain data in the radial direction of the part to be welded.

Furthermore, both potentiometers 6 of the sensor 60 during rotation
Data on the misalignment amount of the welded portion can be obtained from the difference in detected values of 1.62.

As described above, the copying device 6 is capable of simultaneously detecting three items, the axial direction, the radial direction, and the misalignment amount, over the entire circumference as the copying data essential for automatic welding of the inner surface of the tube.

After welding is completed, the appearance of the weld bead can be inspected by observing the image on the monitor TV 16 using the TV camera 66, and the width of the weld bead can also be inspected by measuring the image dimensions. Actual dimensions can be estimated.

Furthermore, the welding excess height can be easily measured as follows by using tracing data. This can be achieved by retracting the welding head 4 a little, then bringing the contact 610 of the front potentiometer 61 into contact with the center of the weld bead (the highest position from the inner surface of each tube), and automatically tracking the weld bead. It will be done. potentiometer 6
1 at the center of the weld bead, automatic tracking is possible because position data in the tube axis direction of the tracing data and mounting of the potentiometer 61 in the tube axis direction are performed based on the position. In this way, potentiometer 6
1, measure the distance from the tube axis to the weld bead. Then, the distance from the tube axis to the inner surface of the tube for both tubes that are butted together.

Since h2 is known from the radial position and misalignment data of the respective tracing data, the height of the weld bead from the inner surface of each pipe, that is, the weld excess height, is calculated as h1-h and h2-h, respectively. It can be done.

The welding cart B configured as described above requires a control signal line, a power line, a welding power line, an air hose for shielding gas, etc. in order to perform automatic welding.

In this embodiment, after taking measures to prevent noise in the signal lines, a composite control cable is used that integrates these into a single cable, making it easier to handle. It can be taken out from the end, and there is no need to rotate it around inside the cart during welding. In addition, in the past, when these individual cables were routed through the pipe as the welding cart moved, there were problems such as being stepped on by the cart or being damaged due to the cables sliding into contact with each other. It can be arranged around the axis without sliding contact, and in particular in this configuration, a hollow ball joint is used to connect each bogie, so some kind of protection against the guide lobe R is provided to connect the guide lobe. By inserting it together with R, it is possible to completely protect the inside of the work unit without exposing it to the outside.

Next, the control system of the apparatus of the present invention will be explained. 1st
FIG. 2 is a block diagram showing an embodiment of the configuration of the control system of the device of the present invention, in which a control operation section 13 equipped with a CPU 130 installed outside the pipe is connected to the inside of the pipe S via a control cable 17. It sends and receives signals to welding cart B to control welding. The off-line computer 14 is provided to create data on basic welding conditions, which will be described later, according to the inclination angle of the pipe in the welded part, and the data is input to the CPU 130 via a floppy disk or the like. It has become. The CPU 130 is equipped with a program that combines and edits this data and the tracing data to create optimal welding execution conditions, and issues a control signal to the welding cart B to perform welding under these conditions. Control operation part 3
Monitors TV15 and 16 are connected to the monitor T.
V15 is for displaying the welding execution conditions. The monitor TV 16 includes a TV camera 66 mounted on the copying device 6,
An image of one of the arc monitoring TV cameras 55a and 55b is selected and displayed. The control operation section 13 is also equipped with an interrupt control circuit (not shown) that manually corrects and changes the welding execution conditions using an operation dial, etc. when an abnormality is detected by arc monitoring. The value can be confirmed on the screen of the monitor TV 15.

FIG. 13 is a block diagram showing an input/output system in the CPU 130. First, detection signals from various sensors of the welding cart B are input to the CPU 130 via an A/D converter (not shown). . That is, potentiometer 2
04 and 32 output detection signals of the amount of rotation and rotation speed of the inner cylinder 2, and the detected value of the potentiometer 204 is input as the cumulative angle, so even if the inner cylinder 2 is rotated in the opposite direction, the angle will not change. It is designed to be added rather than subtracted.

Next, each output signal of the tacho generators 212 and 231 is inputted as the rotation speed of the inner cylinder 2 and the supply speed of the welding wire. Detection signals from the potentiometers 263 and 253 are inputted as the position of the welding head 4 relative to the inner tube 2 in the tube axis direction and the radial direction, respectively. In addition, posture detector 2
Each of the output signals 08 and 209 is input as the attitude of the welding cart B in the pipe line S, that is, the inclination of the pipe line S and the rolling angle of the inner cylinder 2.

As the detection signal of the copying device 6, each detection signal of the potentiometers 61 and 62 in the sensor 60 is inputted.

In addition, the CPt1130 includes a copying switch S1 for starting the collection of copying data by the copying device 6, and a case where the operator traces the line to be welded on the image taken by the TV camera 66, that is, on the screen of the monitor TV 16 during data collection. To,
Remote control switches S2 and s3 are connected to move the welding head 4 in the tube axis direction.
When the notch is turned on, the tube axial movement motor 26 is driven, and when the switch S2 (or S3) is turned on, the welding head 4 is moved in the advancing direction or the retracting direction.

Furthermore, an input interface 132 is connected to the CPU 130 for reading data on a floppy disk, that is, data on basic welding conditions based on the inclination angle of the pipe created on the offline computer 14.
130 has a built-in memory 131 that stores tracing data and data of appropriate welding conditions created using the tracing data and data of basic welding conditions.

On the other hand, on the output side of the CPU 130, there is first a welding cart B.
Various motors are connected via a drive circuit (not shown). That is, the axial movement motor 26 and the radial movement motor 25 move the welding shaft 4 in the tube axis and radial directions. A wire supply motor 23 supplies welding wire to the torch 5, and a head angle motor 51 sets the inclination angle of the torch 5.

In addition, the CPt1130 includes a welding power supply circuit 18a, a welding voltage adjustment device 18b, and a solenoid valve 19 for the shielding gas supply system.
etc. are also connected, and these operations are controlled during welding. As the welding power source, an inverter pulse power source with excellent arc generation properties, spatter-free properties, and arc stability is used, and a large-capacity power source is used to cope with the lengthening of the control cable 17. Furthermore, as the shielding gas, argon and carbon dioxide gas are used as active gases for MAG welding, as in the past.

Furthermore, a display device (not shown) is also connected to the CPU 130 for displaying the detected values of the monitor TV 15, the posture detectors 208, 209, and the like.

Next, a procedure for welding the entire circumference inside the pipe S using the apparatus of the present invention configured as described above will be explained. first,
The welding cart B is driven through the pipe S, stopped at a position in front of the joint of the pipe to be repaired, and is fixed within the pipe by actuating the clamp mechanism 10. Then, the attitude of the welding cart B at this position, that is, the inclination angle of the pipe line S, is detected by the attitude detector 208. Next, using the off-line computer 14, data of basic welding conditions corresponding to the angle of inclination are used to create a plurality of patterns for typical mismatching determined in advance through experiments. As the basic welding conditions, the following various conditions are set corresponding to each position of the torch rotated in the circumferential direction, that is, the cumulative angle.

That is, the rotation speed, the position and inclination angle of the torch in the tube axis and radial direction, the on/off of the welding power source, the adjustment position of the welding voltage,
These are the supply speed of welding wire and each element of riving (one angle, speed, amplitude, pitch, etc.). The reason for creating multiple patterns of such basic welding conditions is that in conventional automatic welding, there is only one pattern of welding conditions, but in cases where the amount of misalignment or root gap varies within one joint, such as with existing pipes. This is because automatic welding was not possible.

This is because conventional automatic welding uses a single groove shape at the joint (normally, the amount of misalignment is OR
) is assumed. Therefore, in this example, by assuming the variation amount of misalignment and creating data of multiple patterns of welding conditions corresponding to a plurality of typical misalignment amounts, it is easy to use this data to perform actual welding. Interpolated data can be calculated according to variations in misalignment, making it possible to handle automatic welding. In this case, the data on the basic welding conditions is used as a mismatch, but the root gap and groove angle can be similarly controlled by creating data.

Next, the data of the basic welding conditions created in this way is sent to the CPU of the control operation section 13 via a floppy disk.
130.

When this is completed, copying data is collected by the copying device 6. FIG. 14 is a flowchart showing the control procedure. First, before starting control, set the torch 5 as the base point,
That is, the clock position is set to 6 o'clock. This is done by using the detected value of the attitude detector 209. When this setting is made, the captured image of the TV camera 66 is displayed on the monitor TV 16.
, and as mentioned above, the sensor 6 of the copying device 6
Since the potentiometers 61 and 62 of 0 are respectively arranged in the tube axis direction via the line to be welded at the joint part, when the base point position setting of the torch 5 is completed, the welding head 4 is moved in the radial direction, Each of the contacts 610 and 620 is brought into contact with both of the butted tubes, and the copying device 6 is set at the initial setting position.

Then, when the worker turns on the copying switch S1, the CPU 130 starts copying control (step S1). First, the CPU 130 drives the swing motor 21 to rotate the copying device 6 clockwise when viewed from the front (step S2), and reads the detected value p1 of the potentiometer 61 and the detected value pt of the potentiometer 62, respectively (step S3). .S4).

Then, in step S5, the radial movement motor 25 is driven so that the detected value p2 of the rear potentiometer 62 matches a predetermined value (steps 36 to S8).

During this time, the operator moves the copying device 6, that is, the welding head 4, so that the line to be welded matches the fixed point on the screen of the monitor TV 16.
is moved in the tube axis direction along the line to be welded, so each switch S2. It is determined whether S3 is on or off, and depending on the result, the tube axial direction movement motor 26 is driven to rotate in a desired direction (steps 39 to 512).

In the next step S13, it is determined whether the cumulative angle has advanced by a predetermined angle (in this embodiment, scanning data is collected in units of 0.5 degrees), and if it has advanced, the detected value of each potentiometer is used as data of the misalignment amount. Then, the radial position is read from the detected value of the potentiometer 253, and the detected value p is stored as radial position data (step S15.81).
6). Similarly, the detected value p of the potentiometer 263 is read and stored as position data in the tube axis direction (step S1?, 518).

The above process is repeated for each predetermined angle, and when the cumulative angle reaches 360 degrees (step 519), that is, when the copying device 6 has collected one revolution's worth of copying data, in the next step S20, the clock The tracing data collected using the approximately 12 o'clock position as the base point is converted so that the 6 o'clock position of the torch 5, at which welding actually starts, is used as the base point, and the tracing control is completed.

When the tracing data is collected as described above, automatic welding of the entire circumference of the joint portion is performed using this tracing data and the data of the basic welding conditions. Prior to this, the welding point 4 is set to the initial setting position for welding as shown in FIG.

FIG. 15 and FIG. 16 are flowcharts showing the procedure of automatic welding control. First, when control is started by the operator, the CPU 130 sets this to an initial state (step S1), and then reads the basic welding data and tracing data from the memory 131 (step S2.33).
Next, these are combined and edited, and data of the optimum welding execution conditions at the base position of the torch 5 is calculated by interpolation (step S4).

When this is calculated, the current detected value of the radial position of the torch 5 is read in step S5, and then it is determined whether this detected value matches the command value of the radial position of the optimal welding execution condition. S6), if they are different, the radial movement motor 25 is driven to make them match, and the torch 5 is moved in the required direction (steps 37 to S9).

Thereafter, the tube axial direction movement motor 26 and the tilt angle motor 51 are similarly driven so that the tube axial direction position and inclination angle of the torch 5 respectively match the command values of the optimum welding execution conditions (steps SL1 to 519).

By the above-described operation, the torch 5 is placed at the optimum position according to the shape of the part to be welded at the base position.

Then, in the next step S20, it is determined which command to turn on the welding power source has the highest priority among the welding conditions, and if this command is on (or off), the welding power source circuit 18a turns on the welding power source (
or off) (steps 520-522). In addition,
At the same time as this welding power source is turned on, the solenoid valve 15 is operated to supply shielding gas.

Hereinafter, the voltage position, the supply speed of the welding wire, the rotation speed of the inner cylinder 2, that is, the circumferential movement speed of the torch 5 are set to the command values of the optimal welding execution conditions, respectively (steps S23 to S525),
In the next step S26, it is determined whether the cumulative angle has actually progressed or not, and if it has not progressed, the process returns to step S4 and the above-mentioned data is held.

Here, the arc is generated when the welding power source is turned on and the welding wire supply speed is 0 or more, that is, when the wire is supplied. Normally, the welding power source is initially turned on and an idling time is provided in which no wire is supplied, so data is held and idling is performed as long as the cumulative angle does not advance.

If the cumulative angle has actually progressed in step S26, in order to set the optimal welding execution condition at the next cumulative angle position from the base position, a predetermined angle is added to the cumulative angle of the currently set optimal welding execution condition, that is, the scanning data The collected angle of 0.5 degree in a predetermined unit is added, and it is determined in step S28 that welding has not been completed, and the process returns to step S2. As a result, step S2. In S3, the data of the cumulative angular position that will be the next torch position is read, the optimal welding execution condition at that angular position is similarly calculated, and its command value is set. By repeating the above process until it is determined that the welding is complete, the optimal welding according to the groove shape is automatically performed without deviating from the line to be welded all around the inner surface of the pipe. It will be done.

〔effect〕

As described above, in the tube inner surface automatic welding device according to the present invention, firstly, when the welding machine runs inside the pipe, the track-type running section equipped with the running belt contacts the pipe inner surface and rolls as it runs. Therefore, the welding machine can be run on the slopes and curved pipes in the existing pipelines that make up the three-dimensional piping, and it can also be used to weld the gaps between pipes that are butted together in dresser compling, or the steps and eyes of sleeve joints. It is also possible to easily pass through the different parts due to the characteristics of the belt.

Next, when fixing the welding machine inside the pipe, a plurality of clamp arms arranged evenly in the circumferential direction are erected in the radial direction from the welding machine using the annular cylinder part provided at the outermost part of the welding machine.
Bring it into contact with the inner surface of the tube. As a result, the raising motion of each clamp arm is performed synchronously, so that the welding machine is accurately fixed at the tube axis position, and the accuracy of tracing the line to be welded and welding can be improved.

In addition, the cylinder part is equipped with a cylindrical piston, and the welding machine body is inserted into the cylinder, so the outer diameter of the welding machine when equipped with a cylinder can be made as small as possible, and it will not interfere with the passage of the curved pipe part. On the other hand, since the cylinder chamber has sufficient capacity, a large fixing force can be obtained.

During welding, the torch can be tilted in the direction of the tube axis around the line to be welded with the torch facing the line to be welded depending on the groove shape, making it possible to efficiently handle fillet welding at stepped portions. , the number of welding passes can be reduced compared to conventional equipment,
The working time can be shortened and the appearance of the weld bead can also be improved.

As described above, the present invention is extremely effective not only in welding newly constructed pipes but also in repair welding in existing pipes, which has been difficult in the past.

[Brief explanation of drawings]

1 and 2 are a side sectional view and a front view of a welding cart according to the present invention, FIG. 3 is an enlarged side sectional view of the clamp mechanism and running section, and FIG. 4 is a line IV-rV of FIG. 1. 5 is a plan sectional view of the welding head drive unit, FIGS. 6 and 7 are front and side views of the welding head during welding, and FIG. 8 is a side view of the welding head when traveling inside a pipe. Figure 9 is a side view when the copying device is in use, Figure 10 is an external perspective view of the posture detector, Figure 11 is a schematic configuration diagram of the construction equipment, Figure 12 is a block diagram of the control system, and Figure 13. 14 is a block diagram showing the input/output system of the CPU, FIG. 14 is a flowchart showing the control procedure of the copying device, and FIGS. 15 and 16 are flowcharts showing the control procedure of automatic welding. B... Welding trolley D... Towing trolley 1... Guide rope insertion tube 2... Inner tube 3... Outer tube 4...
Welding head 5...torch 6...copying device 8,9
... Traveling section 10 ... Clamp mechanism 11 ... Clamp arm 13 ... Control operation section 21 ... Swing motor 24 ... Drive unit 51 ... Tilt motor
85... Running belt 101... Air cylinder 1
02...Piston tube 104...Cylinder tube 130...CPU Patent Applicant: Sumitomo Metal Industries, Ltd. and 2 other agents: Patent attorney Noboru Kono Funeral map for husband's funeral

Claims (1)

[Scope of Claims] 1. An inner surface of a pipe, which is equipped with a welding machine that is connected to a traveling machine, travels within the pipe, and rotates a welding torch in the circumferential direction of the pipe in a stopped state to weld the entire circumference of the inner surface of the pipe. In the automatic welding device, the welding machine includes a plurality of crawler-type running parts arranged at the tip and rolling in contact with the inner surface of the pipe, and track-type running parts arranged equally in the circumferential direction and standing up in the radial direction and contacting the inner surface of the pipe. A plurality of arms are pivotally supported so that the arms can be brought into contact with each other, a piston cylinder is connected to the arms and fitted onto the fuselage with its axis in the longitudinal direction of the fuselage, and a piston cylinder is fitted onto the fuselage to allow the arms to stand up or fall down. A cylinder section that is fitted and fixed to the fuselage body and includes a cylinder tube that forms an annular cylinder chamber between the piston barrel and the piston barrel for moving the piston barrel in the longitudinal direction of the fuselage, and the welding torch facing the line to be welded. and a welding torch tilting part that supports the axis of the welding torch so that it can be tilted in the pipe axis direction around the line to be welded.