JP2008114279A - Arc welding apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arc welding apparatus which can perform a weaving weld precisely and has a weld torch of a simple structure. <P>SOLUTION: An electrode rod 19 is positioned in a state tilted to an angular displacement axis L1 of the torch. A tip portion 19d of the electrode rod 19 swings with a swing angular around the angular displacement axis of the torch by a torch swing drive means 24. The weaving weld is performed by moving a base part 21 in the welding direction X using a robot 30, while swinging the tip portion 19d of the electrode rod 19. Even when the electrode rod 19 is swung, an intersecting point P1 of the electrode rod 19 with the angular displacement axis L1 of the torch stays without moving in the swing direction. Therefore, even if a bevel width is narrow, the weaving weld can be conducted precisely while preventing the weld torch 22 and the electrode rod 19 from contacting with a work 18 to be welded. Furthermore, this mechanism does not swing and move the electrode rod 19 in relation to the weld torch 22, so that the structure can be simplified. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an arc welding apparatus, and more particularly to a TIG welding apparatus that welds a work to be formed with a narrow groove.

  A first prior art TIG welding apparatus is disclosed in Patent Document 1. This welding apparatus is attached to a robot hand. The welding apparatus is moved along the joining direction by the robot and can perform two-member welding by performing arc welding in a state of being swung in a zigzag direction perpendicular to the joining direction. .

  A second conventional technology TIG welding apparatus is disclosed in Patent Document 2 [Conventional Technology]. In this welding apparatus, a rod-shaped electrode rod is attached to the tip portion of the torch tube. The electrode rod is fixed while being inclined with respect to the axis of the torch tube so that the angle formed by the axis of the electrode rod and the surface of the base material forms a receding angle. The welding apparatus is moved along the joining direction by the robot, and the two to-be-joined members can be welded by performing arc welding in a state where the torch tube is pivotally displaced about the axis.

  A third prior art welding apparatus is disclosed in [Embodiment of the Invention] in Patent Document 2. This welding apparatus is configured to be able to resonate and vibrate the torch tube in a direction substantially perpendicular to the joining direction. The welding apparatus is moved along the joining direction by a robot and can perform two-member welding by performing arc welding in a state where the torch tube is oscillated and resonated.

Japanese Patent Laying-Open No. 2003-326362 (19th paragraph, see FIG. 1) Japanese Patent Laid-Open No. 11-239878 (4th paragraph, FIG. 6; 37th paragraph, see FIG. 1)

  In the first prior art, it is necessary to rock the tip of the robot in a zigzag manner in correspondence with the weaving operation, and there is a problem that the control of the robot becomes complicated. Further, when the amplitude width for swinging the electrode rod is small, there is a possibility that weaving failure may occur due to the influence of the inertial force of the robot arm. For example, in the case of a butt joint with a narrow groove, the electrode rod may not be positioned and swung accurately, and the electrode rod may not swing sufficiently, or the electrode rod may collide with the groove wall surface. There is a risk of

  In the second and third conventional techniques, it is necessary to use a special welding torch that swings the electrode rod with respect to the welding torch. Further, the structure becomes complicated as compared with a general-purpose welding apparatus in which the welding torch and the electrode rod are fixed. As a result, the welding head is likely to break down, and the reliability of the welding torch may be reduced.

  Accordingly, an object of the present invention is to provide an arc welding apparatus that can perform weaving welding with high accuracy and has a simple structure of a welding torch.

The present invention is fixed to a robot, and a base portion on which a predetermined torch angle displacement axis is set;
With the tip of the electrode rod protruding, a welding torch for detachably attaching the electrode rod;
The welding torch is supported so that the center axis of the electrode rod attached to the welding torch is inclined with respect to the torch angle displacement axis, connected to the base so as to be able to be displaced by a swing angle around the torch angle displacement axis. A torch support to perform,
Including a torch swing driving means for driving the torch support portion to swing at a swing angle about the torch angle displacement axis,
The arc welding apparatus is characterized in that an intersection of the central axis of the electrode rod and the torch angle displacement axis is arranged at a protruding portion of the electrode rod protruding from the welding torch.

  According to the present invention, the base is displaced by the robot, the torch angle displacement axis is arranged along the depth direction of the groove of the workpiece, and the tip of the electrode rod is opened to the workpiece. Placed first. The electrode rod is disposed to be inclined with respect to the torch angle displacement axis. When the torch support driving means displaces the torch support portion about the torch angle displacement axis, the tip of the electrode rod is displaced about the torch angle displacement axis. By moving the base portion in the joining direction by the robot while the tip portion of the electrode rod is swung, the tip portion of the electrode rod can be moved in a zigzag manner, and weaving welding can be performed.

  Even when the tip of the electrode rod is swung, the intersection of the center axis of the electrode rod and the torch angle displacement axis remains without moving in the swinging direction. Further, the welding torch does not move to the tip end side of the electrode rod from the intersection point in the torch angle displacement axis direction even when the tip portion of the electrode rod is swung. Therefore, by arranging the intersection point outside the groove opening or the opening, weaving welding can be performed while preventing the welding torch and the electrode rod from coming into contact with the workpiece even when the groove width is narrow. . Further, in the present invention, since the electrode rod is not configured to swing with respect to the welding torch, the structure can be simplified.

  The present invention is characterized in that the welding torch is mounted coaxially with a linear rod-shaped electrode rod having a tapered tip.

  According to the present invention, it is not necessary to use a specially shaped electrode bar in order to perform the weaving operation by attaching the electrode rod having a linear bar shape to the welding torch. Therefore, a general-purpose welding torch and electrode rod can be used, and an increase in manufacturing cost can be suppressed.

The present invention is a non-melting electrode type arc welding apparatus,
A filler material guide for guiding the filler material to an area near the electrode rod attached to the welding torch;
A filler material guide support portion that is connected to the base portion so as to be capable of rocking angle displacement around a filler material angular displacement axis extending parallel to the torch angle displacement axis, and supports a filler material guide;
The filler material guide support part is linked to the swing angle displacement of the torch support part so that the filler material guided by the filler material guides to the electrode rod attached to the welding torch. Guide swing drive means for driving the swing angle displacement around the axis is further included.

  According to the present invention, the guide swing driving means drives the filler material guide support portion to swing angle around the melt material angular displacement axis in conjunction with the swing angle displacement of the torch support portion. Accordingly, the filler material can be swung according to the swing of the electrode rod, and even when the electrode rod is swung, the positional deviation between the electrode rod and the filler material can be suppressed. .

  In the present invention, the guide swing driving means transmits the power of the torch swing drive means to drive the filler material guide support portion to swing angle about the melt material angular displacement axis. It is characterized by being realized by.

  According to the present invention, the guide swing drive means is realized by a power transmission mechanism that transmits the power of the torch swing drive means to the filler material guide support portion. Thus, since the filler material guide support portion is angularly displaced, a separate drive source is not required, and the operations of the filler material guide support portion and the torch support portion can be linked with a simple structure.

  The present invention further includes a groove position detecting means connected to the base, detecting a relative position of the base with respect to the groove position, and providing a detection result to the robot.

  According to the present invention, the groove position detecting means detects the relative position of the base with respect to the groove position, and gives the detection result to the robot so that the robot corrects the deviation of the base with respect to the groove position. The base can be moved. Accordingly, it is possible to prevent the electrode bar from interfering with the object to be joined even when the groove forming accuracy is low during the weaving welding.

  The present invention further includes a groove depth detecting means connected to the base portion for detecting the depth of the groove position.

  According to the present invention, the groove depth detecting means can detect the groove depth, thereby performing control according to the detection result. For example, based on the groove depth, the joining quality can be further improved by changing the supply amount of the filler metal, changing the voltage, and changing the height of the base.

  The present invention is a welding facility including the arc welding apparatus and a robot for moving the arc welding apparatus in a displaced manner.

  According to the present invention, the weaving operation can be performed by moving the arc welding apparatus by the robot. The robot does not need to swing and move the arc welding apparatus in a direction crossing the joining direction, and can easily control the robot.

  According to the first aspect of the present invention, weaving welding can be performed in a state where the welding torch and the electrode rod are fixed to each other, and it is necessary to use a special welding torch that swings the electrode rod with respect to the welding torch. There is no. Therefore, the structure of the welding torch can be simplified, and the reliability of the welding torch can be improved. In addition, by arranging the intersection of the center axis of the electrode rod and the torch angle displacement axis outside the groove opening or the opening, even if the groove width is narrow, the welding torch and the electrode rod are attached to the object to be joined. Weaving welding can be performed while preventing interference. Accordingly, even when the welding torch itself is formed in a large size, a groove-shaped butt joint having a narrow groove width can be joined. By narrowing the groove width, it is possible to suppress the influence of structural change and thermal strain due to heat, and it is possible to improve the quality of the members to be joined.

  According to the second aspect of the present invention, weaving welding can be performed using a general-purpose welding torch and electrode rod, and an increase in manufacturing cost can be suppressed.

  According to the third aspect of the present invention, the filler material guide is rocked in accordance with the rocking of the electrode rod. As a result, weaving welding can be performed while suppressing the positional deviation between the electrode rod and the filler material. As a result, the unevenness of the filler metal can be prevented, and the bead height can be made flat. Moreover, it can prevent that the filler material melted in the vicinity of the groove wall surface is insufficient. As a result, the bonding quality can be improved.

  According to the fourth aspect of the present invention, since the power transmission mechanism is used to realize the rocking mechanism of the filler material guide, there is no need to use a separate driving means. Thus, the interlock between the filler material guide and the electrode rod can be reliably interlocked without performing synchronization control or the like. As a result, it is possible to prevent malfunction of the interlock and to prevent failure of the welding apparatus.

  According to the present invention described in claim 5, by utilizing the groove position detecting means, it is possible to correct the deviation of the base with respect to the groove position, and to prevent the electrode bar from interfering with the workpiece. it can. As a result, even if the groove width is narrow, the electrode rod and the object to be joined are prevented from interfering with each other, and weaving welding can be performed.

  According to the sixth aspect of the present invention, the groove depth detecting means can perform control according to the detection result by detecting the groove depth. For example, based on the groove depth, the joining quality can be further improved by changing the supply amount of the filler metal, changing the voltage, and changing the height of the base.

  According to the seventh aspect of the present invention, the weaving operation can be performed by displacing the arc welding apparatus by the robot. The robot does not need to swing and move the arc welding apparatus in a direction crossing the joining direction, and can easily control the robot.

  FIG. 1 is a front view showing a welding head 100 of an arc welding apparatus 20 according to an embodiment of the present invention. FIG. 2 is an enlarged front view showing a part of the welding head 100. An arc welding apparatus 20 according to an embodiment of the present invention is an apparatus that performs TIG (Tungsten Inert Gas) welding, and is configured to be capable of weaving welding. The arc welding apparatus 20 generates an arc between an electrode rod 19 made of tungsten and an object to be joined 18 in an atmosphere of an inert gas such as argon or helium, and a filler material in the arc generation region. 17 is paid out. The filler material 17 is made of a metal material and is a flexible linear body.

  The filler material 17 is sequentially fed toward the arc generation region, and the melt material 17 and the workpiece 18 are melted in the arc generation region, whereby the melted filler material 17 forms the workpiece 18. Fill the groove. As a result, the two members to be joined constituting the article 18 can be welded.

  The workpiece 18 is butt welded by the arc welding apparatus 20. In the present embodiment, a V-shaped groove or an X-shaped groove is formed in the workpiece 18 before welding. The groove extends in a predetermined joining direction X. The arc welding apparatus 20 moves the electrode rod 19 in the joining direction X, and swings and displaces the electrode rod 19 in the swinging direction Y intersecting the joining direction X, thereby performing arc welding. The weaving can be welded.

  The arc welding apparatus 20 has a welding head 100. The welding head 100 is used as an end effector connected to the articulated robot 30, and its position and posture are changed by the articulated robot 30. As a result, arc welding can be performed at an arbitrary position. The welding head 100 includes a base portion 21, a welding torch 22, a torch support portion 23, a torch swing drive means 24, a filler material guide 25, a filler material guide support portion 26, and a guide swing drive means 27. It is comprised including. The base 21 is fixed to the end of the articulated robot 30 and a predetermined torch angle displacement axis L1 is set.

  The base portion 21 is set with a joining direction X extending along the groove during welding and a swinging direction Y for swinging the welding torch 22. The joining direction X and the swinging direction Y extend along a plane perpendicular to the torch angle displacement axis L1. The joining direction X and the swinging direction Y are orthogonal to each other. Of the joining directions X, the direction in which the base 21 advances during joining is referred to as a joining direction front X1, and the direction opposite to the joining direction front X1 is referred to as a joining direction rear X2.

  The welding torch 22 detachably mounts the electrode rod 19 with the tip 19d of the electrode rod 19 protruding. The welding torch 22 generates an arc between the electrode rod 19 and the workpiece 18. Specifically, the welding torch 22 electrically connects the electrode rod 19 and a power source, applies a terminal voltage from the power source to energize the electrode rod 19, and generates a potential difference with respect to the workpiece 18. The welding torch 22 guides the inert gas supplied from the inert gas supply source and blows it to the arc generation region, thereby preventing the influence of oxygen, nitrogen, etc. in the atmosphere, and oxidizing and nitriding the molten portion. prevent. Further, the welding torch 22 cools the electrode rod 19 with the coolant supplied from the coolant source, and prevents the temperature rise of the electrode rod 19. In the present embodiment, the welding torch 22 is provided with an AVC device 51 described later.

  The welding torch 22 is formed integrally with the electrode rod 19 with the electrode rod 19 attached. The welding torch 22 has a cylindrical casing that accommodates most of the electrode rod 19. The center axis of the electrode rod 19 attached to the welding torch 22 is arranged coaxially with the center axis of the welding torch 22. Hereinafter, the central axis of the welding torch 22 is referred to as an electrode axis L2. A protruding portion 19c of the electrode rod 19 protruding from the opening of the welding torch 22 has a cylindrical portion 19a formed in a cylindrical shape coaxial with the electrode axis L2, and a conical shape connected to the cylindrical portion 19a and coaxial with the electrode axis L2. And a conical portion 19b formed so as to taper away from the welding torch 22. In the present embodiment, the diameter of the electrode rod 19 is set to 3.2 mm, and the protruding portion 19 c protruding from the welding torch 22 is set to about 27 mm.

  The torch support portion 23 is coupled to the base portion 21 so as to be able to be displaced by a swing angle around a torch angle displacement axis L <b> 1 set on the base portion 21. Moreover, the torch support part 23 supports the axial direction intermediate part of the welding torch 22 so that attachment or detachment is possible. Therefore, the welding torch 22 supported by the torch support portion 23 is provided so as to be angularly displaceable around the torch angle displacement axis L1 together with the torch support portion 23.

  The torch support portion 23 has a support portion 32 that supports the welding torch 22. The support portion 32 is disposed away from the torch angle displacement axis L1 in the joining direction rear X2. Further, the welding torch 22 supported by the support portion 32 advances from the supported portion supported by the support portion 32 in the axial direction toward the opening of the welding torch 22 and advances in the joining direction forward X1, and the torch angle. It inclines so that it may approach the displacement axis L1. Thus, the welding torch 22 is supported by the torch support portion 23, whereby the electrode axis L2 is inclined with respect to the torch angle displacement axis L1. In the present embodiment, the angle θ1 between the torch angle displacement axis L1 and the electrode axis L2 is set to 20 °.

  In a state where the welding torch 22 is supported by the torch support portion 23, the torch angle displacement axis L1 and the electrode axis L2 intersect at a preset intersection P1. An intersection P1 between the torch angle displacement axis L1 and the electrode axis L2 is a protrusion 19c protruding from the welding torch 22 in the electrode rod 19, and is arranged at one point in a region excluding the tip 19d. The dimension H3 in the direction along the torch angle displacement axis L1 from the tip 19d of the electrode bar 19 to the intersection P1 is set to be substantially the same as the depth dimension H4 of the groove 16 to be joined. As a result, the tip 19 d of the electrode rod 19 can be disposed in the vicinity of the groove bottom surface 15 facing the groove 16. In the present embodiment, the intersection P1 is set at a position moved from the tip 19d of the electrode bar 19 by about 19 mm along the electrode axis L2. In arc welding, the welding torch 22 is disposed in the joining direction rear X2 with respect to the torch angle displacement axis L1. Further, the tip 19d of the electrode rod 19 is disposed in the joining direction front X1 with respect to the torch angle displacement axis L1.

  FIG. 3 is a cross-sectional view showing the torch swing driving means 24. The torch swing driving means 24 drives the torch support portion 23 with respect to the base 21 by swinging angle displacement about the torch angle displacement axis L1. The torch swing drive means 24 includes a swing motor 33 that rotationally drives the output shaft 33 a and a power transmission mechanism 34. The swing motor 33 is realized by a servo motor capable of controlling the amount of angular displacement of the output shaft 33a. The swing motor 33 is fixed to the base portion 21 so that the output shaft 33a can be rotationally driven.

  The power transmission mechanism 34 is a mechanism that transmits the rotational force of the output shaft of the swing motor 33 to the torch support portion 23. The power transmission mechanism 34 transmits power by gear transmission, and each gear is disposed in the internal space of the base portion 21. In the present embodiment, the power transmission mechanism 34 includes a power input gear 34a, an intermediate gear 34b, and a power output gear 34c. The power input gear 34a is fixed coaxially with the output shaft of the swinging motor 33 and is supported by the swinging motor 33 so as to be rotatable about its axis. The intermediate gear 34b meshes with the power input gear 34a and is supported by the base portion 21 so as to be rotatable about its axis. The power output gear 34c meshes with the intermediate gear 34b and is supported by the base portion 21 so as to be rotatable about its axis. The power output gear 34c has a connecting shaft 34d fixed coaxially. The connecting shaft 34 d is provided on the base portion 21 and is integrally connected to the torch support portion 23, thereby supporting the torch support portion 23 with respect to the base portion 21. The rotation axes of the gears 34a, 34b, 34c are set parallel to each other. The rotational axis of the power output gear 34c is arranged to coincide with the torch angle displacement axis L1.

  The swinging motor 33 drives the output shaft 33a to swing around the angular displacement axis, so that the torch support 23 together with the connecting shaft 34d can swing around the torch angular displacement axis L1. The power transmission mechanism 34 also serves as a speed reducer that decelerates the power of the swing motor 33. The oscillating motor 33 applies power to the torch support portion 23 via the power transmission mechanism 34 so that the oscillating motor 33 can be separated from the arc generation region as much as possible. Reaching the motor 33 can be prevented.

  The filler material guide 25 guides the filler material 17 to a region in the vicinity of the tip of the electrode rod 19 attached to the welding torch 22. The filler material guide 25 is formed with an insertion hole through which the filler material 17 is inserted. The tip of the filler material 17 that has passed through the insertion hole is located in a region near the tip of the electrode rod 19. The filler material 17 is fed from the state wound around the reel by the feeding device and passes through the insertion hole of the filler material guide 25 to be fed to an area near the tip of the electrode rod 19. .

  The filler material guide support portion 26 is coupled to the base portion 21 so as to be capable of swinging and oscillating about the filler material angular displacement axis L3 set on the base portion 21. Here, the filler metal angular displacement axis L3 is an axis that is set in advance in the base 21, extends parallel to the torch angle displacement axis L1, and is disposed in the joining direction front X1 with respect to the torch angle displacement axis L1. The filler material guide support portion 26 supports the filler material guide 25. As a result, the filler material guide 25 supported by the filler material guide support portion 26 is provided together with the filler material guide support portion 26 so as to be angularly displaceable around the filler material angular displacement axis L3. The filler material guide 25 supported by the filler material guide support portion 26 is disposed in the joining direction front X1 with respect to the torch angle displacement axis L1.

  The filler material guide support portion 26 includes a grip portion 35 that grips the filler material guide 25 and a cylindrical shaft portion 36 that is connected to the grip portion 35. The shaft portion 36 extends coaxially with the filler metal angular displacement axis L3 and is configured to be capable of oscillating angularly around the filler metal angular displacement axis L3. As for the axial part 36, the axial direction one end part 36a is supported by the base 21, and the holding part 35 is connected with the axial direction other end part 36b.

  The guide swing driving means 27 is configured to change the swing angle of the torch support portion 23 so that the filler material 17 guided by the filler material guide 25 is directed toward the tip end portion 19d of the electrode rod 19 attached to the welding torch 22. In conjunction with this, the filler material guide support portion 26 is driven to swing angularly about the filler metal angular displacement axis L3.

  FIG. 4 is a perspective view showing two members to be joined 18a and 18b constituting the article 18 to be joined. In the present embodiment, the two members to be joined 18a and 18b to be butt-joined are two short cylindrical thin-walled tubes formed to have substantially the same diameter. With such two short tubular thin tubes arranged coaxially, the axial end of one short tubular thin tube and the axial end of the other short tubular thin tube are abutted against each other. In this state, a groove 16 is formed at the butt portion. The groove 16 goes around the pipe in the circumferential direction. The joint portion where the groove 16 is formed is arc welded by the arc welding apparatus 20. Thus, the to-be-joined object 18 with which the short cylindrical thin wall pipe was welded is used as a liquefied natural gas (LNG) storage tank having a diameter of 5 to 10 m, a height of 10 to 20 m, and a plate thickness of 25 mm, for example. The groove 16 is formed in a narrow groove shape having a depth dimension larger than the width dimension. Specifically, the depth dimension is about 18 mm and the width dimension is about 8 mm.

  FIG. 5 is a sectional view showing the groove 16 of the workpiece 18 from the front X1 in the joining direction to the rear X2 in the joining direction in order to explain the waving operation. In arc welding, the base 21 is displaced and driven by the multi-joint robot 30, the torch angle displacement axis L 1 is arranged at the center position in the width direction of the groove 16 of the workpiece 18, and the bonding direction X is the groove 16. Arranged along the distraction direction. Further, the electrode rod 19 is inserted into the groove 16 of the workpiece 18 by the articulated robot 30. At this time, the distal end portion 19 d of the electrode rod 19 is disposed in the vicinity of the groove bottom surface 15 facing the groove 16, and is disposed with a gap from the groove bottom surface 15.

  When the torch swing drive means 24 causes the torch support portion 23 to swing around the torch angle displacement axis L1, the tip 19d of the electrode rod 19 swings around the torch angle displacement axis L1. Specifically, when viewed on a cut surface perpendicular to the bonding direction X, as shown in FIG. 5A, a standard state is obtained in which the torch angle displacement axis L1 and the electrode axis L2 coincide.

  As shown in FIG. 5 (2), the tip portion 19d of the electrode rod 19 is compared with the standard state by angularly displacing the torch support portion 23 in the circumferential direction around the torch angle displacement axis L1 with respect to the standard state. Then, it moves in the rocking direction Y1 in the groove 16. Further, as shown in FIG. 5 (3), the tip portion 19d of the electrode rod 19 is positioned in the groove as compared with the standard state by angularly displacing the torch support portion 23 around the torch angle displacement axis L1 in the circumferential direction. To move in the other swing direction Y2.

  By oscillating the torch support portion 23 about the torch angle displacement axis L1, the first oscillating state shown in FIG. 5 (2) and the second oscillating state shown in FIG. 5 (3) are alternately performed. Repeatedly, the tip 19d of the electrode rod 19 alternately moves in one swing direction Y1 and the other swing direction Y2. Even when the tip 19d of the electrode bar 19 is swung in the swing direction Y, the intersection P1 between the torch angle displacement axis L1 and the electrode axis L2 remains without moving in the swing direction Y. Therefore, in the vicinity of the intersection P1 in the electrode rod 19, the swing width swinging in the swing direction Y is small.

  Thus, by arranging the intersection point P1 outside the groove opening or the opening, even when the groove width is narrow, when the electrode bar 19 is swung, the electrode bar 19 is moved to the inner wall 14a, It can prevent contacting 14b. In particular, by arranging the intersection P1 in the vicinity of the opening of the groove 16, contact with the workpiece 18 is prevented, and the tip 19d of the electrode rod 19 is swung in the rocking direction Y at a deep position of the groove 16. be able to.

  In the standard state, the distance in the direction perpendicular to the torch angle displacement axis L1 from the torch angle displacement axis L1 to the tip 19d of the electrode rod 19 is defined as H1. The swing direction distance from the torch angle displacement axis L1 to the inner walls 14a, 14b of the workpiece 18 is set to H2. Assuming that an angle range in which the welding torch 22 is angularly displaced about the torch angle displacement axis L1 is ± θ2, a relationship of H1 · sin (θ2) <H2 is set. As a result, the electrode rod 19 can be prevented from contacting the inner walls 14a and 14b of the article 18 to be joined. In the present embodiment, the distal end portion 19d of the electrode rod 19 does not contact the inner walls 14a and 14b of the workpiece 18 by displacing the welding torch 22 by ± 20 ° around the angular displacement axis L1. 14a and 14b can be alternately moved in the swing direction Y over the vicinity.

  Further, the welding torch 22 can generate an arc between the tip 19d of the electrode rod 19 and the groove bottom surface 15, and a part of the workpiece 18 can be melted by the arc. Further, the filler material 17 is sequentially fed to the arc generating region, and the filler material 17 and the workpiece 18 are melted in the arc generating region, and the melted filler material 17 forms the workpiece 18. Fill the groove sequentially. As a result, the two members 18a and 18b constituting the workpiece 18 can be welded. In the present embodiment, the arc is generated by the welding torch 22 in a state where the welding torch 22 is displaced by the oscillation angle by the torch support portion 23, so that the arc can be welded while moving in the oscillation direction Y. Further, the tip of the filler material 17 is guided by the filler material guide 25, so that the position near the tip 19 d of the electrode rod 19 that swings following the swing of the tip 19 d of the electrode rod 19. Placed in. Thereby, insufficient melting of the filler material 17 can be prevented.

  Further, as shown in FIG. 5 (2), when the electrode rod 19 swings and moves in one swinging direction Y1, the distal end portion 19d is located most in the swinging direction one Y1, and the proximal end from the distal end portion 19d. As it goes to the part, the swing direction proceeds to the other Y2. This prevents interference between the electrode rod 19 and the workpiece 18 as compared with a case where the electrode rod 19 is parallel to the torch angle displacement axis L1 and the tip portion 19d is located in one of the swing directions Y1. An arc can be generated toward one Y1 in the swing direction, and the melting failure of the inner wall 14a of the one end Y1 in the swing direction of the groove 16 of the workpiece 18 can be prevented.

  Similarly, as shown in FIG. 5 (3), when swinging in the other swinging direction Y2, the distal end portion 19d is positioned most in the other swinging direction Y2 and swings from the distal end portion 19d toward the base end portion. Move in one direction Y1. This prevents interference between the electrode rod 19 and the workpiece 18 as compared with the case where the electrode rod 19 is parallel to the torch angle displacement axis L1 and the tip portion 19d is positioned in the other direction Y2 of the swinging direction. An arc can be generated toward the other swinging direction Y2, and the melting failure of the inner wall 14b of the other end Y2 in the swinging direction of the groove 16 of the workpiece 18 can be prevented.

  FIG. 6 is a plan view showing the movement locus 37 of the torch angle displacement axis L1 and the movement locus 38 of the tip 19d of the electrode rod 19. As shown in FIG. In FIG. 6, the movement locus 37 of the torch angle displacement axis L1 is indicated by a one-dot chain line, and the movement locus 38 of the tip 19d of the electrode rod 19 is indicated by a broken line. The tip 19d of the electrode rod 19 is swung in the swing direction Y within the groove 16 by the torch swing drive means 24, and the base 21 is moved along the extending direction of the groove 16 by the articulated robot 30. Move. At this time, the torch angle displacement axis L <b> 1 passes along the movement locus 37 extending in the extending direction of the groove 16 through the center position in the width direction of the groove 16.

  As a result, the welding head 100 moves the tip 19d of the electrode rod 19 with respect to the workpiece 18 along the extending direction of the groove 16, and swings zigzag in a direction perpendicular to the extending direction. It can be moved along the movement locus 38. As a result, the tip portion 19 d of the electrode rod 19 can be so-called weaving, and a wide bead that extends in the width direction of the groove 16 can be formed.

  FIG. 7 is a cross-sectional view showing a state in which melted filler materials are stacked in layers and the groove 16 of the workpiece 18 is filled. By means of arc welding, the filler material layer 13 in which the melted filler material is solidified in the groove 16 is sequentially laminated in the thickness direction. Thus, by providing the filler material 17 in multiple layers, the groove 16 can be filled with the filler material 17 even when the groove 16 is deep. With the articulated robot 30, the outer periphery of the cylindrical workpiece 18 is rotated a plurality of times with the tip end portion 19 d of the electrode rod 19 spaced apart from the previously formed filler material layer 13 by a predetermined distance. By performing arc welding, a multi-layer stack in which the filler material layer 13 is laminated on the groove 16 can be formed. In this way, uniform welding quality can be obtained over the circumferential direction of the groove 16 by rotating the welding head 100 around the workpiece 18 and performing arc welding.

  As described above, in the present embodiment, the tip portion 19d of the electrode rod 19 is driven to swing angle around the torch angle displacement axis L1 by the torch swing drive means 24. The tip portion 19d of the electrode rod 19 can be moved in a zigzag manner by moving the base portion 21 in the extending direction of the groove 16 by the articulated robot 30 while the tip portion 19d of the electrode rod 19 is swung. Weaving welding can be performed.

  When the tip 19d of the electrode bar 19 is swung, the intersection P1 between the torch angle displacement axis L1 and the electrode axis L2 remains without moving in the swing direction Y. Therefore, in the vicinity of the intersection P1 in the electrode rod 19, the swing width swinging in the swing direction Y is small. Thus, even when the groove width is narrow, the electrode rod 19 can be prevented from coming into contact with the inner walls 14a and 14b of the groove 16, and the weaving welding can be performed.

  Accordingly, even when the welding torch 22 itself is formed in a large size, a groove-shaped butt joint having a narrow groove width can be joined. By narrowing the groove width, it is possible to suppress the influence of heat such as structural change due to heat and thermal strain, internal stress, cracking and material deterioration, and the quality of the joined members to be joined can be improved. Moreover, compared with the case where a groove width is wide, the to-be-joined object 18 can be welded in a short time.

  In particular, when the groove bottom surface 15 is melted, in other words, when the filler metal is welded to the deepest portion, the intersection point P1 between the torch angle displacement axis L1 and the electrode axis L2 is set to be larger than the opening of the groove 16 or the opening. Further, by arranging them outward, weaving welding can be performed while preventing the welding torch 22 and the electrode rod 19 from interfering with the workpiece 18 even if the groove width is narrow.

  In the present embodiment, in the weaving welding, the articulated robot 30 moves the base 21 along a linear movement locus 37 along the extending direction of the groove 16. Therefore, the articulated robot 30 can simplify the displacement driving of the welding head 100 by the articulated robot 30 as compared to the case where the welding head is moved in the joining direction X while being swung in the swing direction Y. Accordingly, the position teaching operation related to the waving operation of the articulated robot 30 can be easily performed. Further, the displacement amount of the tip 19d of the electrode rod 19 with respect to the swinging direction Y can be easily changed only by changing the angular displacement amount by which the welding torch 22 is angularly displaced about the angular displacement axis L1. Further, the displacement amount Y in the swing direction Y can be increased or decreased according to the travel amount of the welding torch 22 in the extending direction of the groove 16. Further, if the electrode rod 19 can enter the groove, even if the groove width is very small, the electrode rod 19 is attached to the inner walls 14a and 14b of the workpiece 18 by reducing the angular displacement amount. Weaving welding can be performed without collision.

  In this embodiment, weaving welding can be performed in a state where the welding torch 22 and the electrode rod 19 are integrally fixed. Therefore, unlike the prior art, it is not necessary to use a special welding torch 22 that swings the electrode rod 19 with respect to the welding torch 22, the structure of the welding torch 22 can be simplified, and the reliability of the welding torch 22 is improved. Can be improved. In the present embodiment, the welding torch 22 is mounted with the electrode rod 19 having a straight bar shape, so that it is not necessary to use a specially shaped electrode rod in order to perform the weaving operation. Therefore, the general-purpose welding torch 22 and the electrode rod 19 can be used, and an increase in manufacturing cost can be suppressed. In addition, by using the electrode rod 19 in the form of a straight bar, when the tip 19d of the electrode rod 19 is consumed by arc welding, the change to another electrode rod 19 can be easily performed. Further, by polishing the tip 19d of the electrode rod 19 that has been consumed by the tip 19d, it can be reused as the electrode rod 19 that can be arc welded, and the number of electrode rods 19 consumed can be reduced. Further, by using a general-purpose welding torch 22 and the electrode rod 19, it is possible to perform normal arc welding by setting the standard state shown in FIG.

  FIG. 8 is a cross-sectional view schematically showing the operation of the guide swing driving means 27 as seen from the section line S8-S8 in FIG. FIGS. 8A to 8C correspond to FIGS. 5A to 5C, respectively. In FIG. 8, one circumferential direction R1 is set clockwise and the other circumferential direction R2 is set counterclockwise. In the present embodiment, the guide swing drive means 27 is realized by a power transmission mechanism that transmits the power of the torch swing drive means 24.

  The guide swing driving means 27 includes a guide body 40, a guide wheel 41, and a link body 42. The guide body 40 is provided on the torch support portion 23. In the torch support portion 23, a first direction A perpendicular to the torch angle displacement axis L1 and a second direction B perpendicular to both the first direction A and the torch angle displacement axis L1 are set. The first direction A and the second direction B are included in one plane perpendicular to the torch angle displacement axis L1. Since the first direction A and the second direction B are set on the torch support portion 23, the first direction A and the second direction B are angularly displaced about the torch angle displacement axis L1 along with the angular displacement of the torch support portion 23 about the torch angle displacement axis L1.

  The guide body 40 has a pair of rail portions 40 a and 40 b that protrude from the torch support portion 23 and extend parallel to the first direction A. Each rail part 40a, 40b is arranged at intervals in the second direction B. As a result, the guide body 40 is formed with a rail groove that is a space extending along the first direction A. Further, the torch angle displacement axis L1 is set at the center position in the second direction of each rail portion 40a, 40b. In other words, the torch angle displacement axis L <b> 1 extends through the rail groove 43. The guide body 40 is angularly displaced around the torch angle displacement axis L <b> 1 together with the torch support portion 23.

  The guide wheel 41 is formed so as to be movable in the first direction A while being prevented from being displaced in the second direction B by being fitted between the rail portions 40a and 40b. The guide wheel 41 is disposed closer to the filler metal angular displacement axis L3 than the torch angular displacement axis L1. The guide wheel 41 is formed in a cylindrical shape in which a rotation axis L4 parallel to the torch angle displacement axis L1 is set, and is realized by a so-called cam follower.

  The link body 42 is formed in a substantially longitudinal shape extending in a direction perpendicular to the torch angle displacement axis L1. The link body 42 has a longitudinal end portion 42a fixed to the shaft portion 36 of the filler material guide support portion 26, and supports the guide wheel 41 at the longitudinal direction other end portion 42b. The guide wheel 41 is supported by the link body 42 so as to be rotatable around its rotation axis L4. Further, the link body 42 keeps the distance from the filler metal angular displacement axis L3 to the guide wheel 41 constant.

  In the standard state shown in FIG. 8 (1), a straight line connecting the filler metal angular displacement axis L3 and the rotation axis L4 of the guide wheel 41 and a straight line connecting the rotation axis L4 of the guide wheel 41 and the torch angle displacement axis L1 are shown. Arranged on the same plane. At this time, the longitudinal direction of the link body 42 and the first direction A of the torch support portion 23 extend in parallel. Further, as shown in FIG. 5A, when viewed on a cutting plane perpendicular to the joining direction X, a standard state is obtained in which the torch angle displacement axis L1 and the electrode axis L2 coincide. In the standard state, the tip 19d of the electrode rod 19 extends from the torch angle displacement axis L1 toward the rotation axis L4 of the guide wheel 41. Further, the tip end portion of the filler material 17 guided by the filler material guide 25 extends from the filler material angular displacement axis L3 toward the rotation axis L4 of the guide wheel 41.

  FIG. 8 (2) shows a state in which the torch support portion 23 is angularly displaced in one circumferential direction R1 around the torch angle displacement axis L1 from the standard state. In this state, the guide body 40 is angularly displaced in the circumferential direction one R1 around the torch angle displacement axis L1 together with the torch support portion 23. At this time, since the distance between the filler metal angular displacement axis L3 and the rotation axis L4 of the guide wheel 41 is maintained constant by the link body 42, the guide wheel 41 is slidably guided in the second direction B by the guide body 40. The link body 42 is angularly displaced in the other circumferential direction R2 around the filler metal angular displacement axis L3.

  FIG. 8 (3) shows a state in which the torch support portion 23 is angularly displaced in the other circumferential direction R2 around the torch angle displacement axis L1 from the standard state. In this state, the guide body 40 is angularly displaced together with the torch support portion 23 in the other circumferential direction R2 around the torch angle displacement axis L1. At this time, since the distance between the filler metal angular displacement axis L3 and the rotation axis L4 of the guide wheel 41 is maintained constant by the link body 42, the guide wheel 41 is slidably guided in the second direction B by the guide body 40. The link body 42 is angularly displaced in one circumferential direction R1 around the filler metal angular displacement axis L3.

  As a result, from the standard state, the torch support portion 23 is pivotally displaced in the circumferential direction one R1 and the other circumferential direction R2 around the torch angle displacement axis L1 alternately, so that the filler guide support fixed to the link body 42 is fixed. The portion 26 can be alternately swung around the filler metal angular displacement axis L3 in the other circumferential direction R2 and the circumferential direction one R1. In this way, the filler material guide support portion 26 is angularly displaced in conjunction with the angular displacement of the torch support portion 23 and at the same time the melt direction is opposite to the angular displacement directions R1 and R2 of the torch support portion 23 in the opposite directions R2 and R1. The material guide support portion 26 can be angularly displaced. Therefore, regardless of the swinging state, the tip end portion 19d of the electrode rod 19 and the tip end portion 17a of the filler metal 17 are arranged toward the rotation axis L4 of the guide wheel 41.

  FIG. 9 is a diagram showing the operation of the electrode rod 19 and the filler material 17 when viewed from the section line S9-S9 in FIG. FIGS. 9 (1) to 9 (3) correspond to FIGS. 5 (1) to 5 (3) and FIGS. 8 (1) to 8 (3), respectively. In FIG. 9, one circumferential direction R1 is set clockwise and the other circumferential direction R2 is set counterclockwise.

  As described above, the filler material guide support portion 26 is angularly displaced in conjunction with the angular displacement of the torch support portion 23. Therefore, when the tip 19d of the electrode rod 19 is displaced in the swing direction Y1 as shown in FIG. 9 (2) from the standard state shown in FIG. 9 (1), the tip 17a of the filler material 17 is also moved. It is displaced in one direction Y1 in the swing direction. 9 (1), when the tip 19d of the electrode rod 19 is displaced in the other swing direction Y2 as shown in FIG. 9 (3), the tip 17a of the filler material 17 also swings. Displacement in the other moving direction Y2. In the present embodiment, the rotational axis L4 of the guide wheel 41 in the standard state, the distal end portion 19d of the electrode rod 19 and the distal end portion 17a of the filler material 17 substantially coincide with each other, so that the distal end portion of the electrode rod 19 The displacement amount in the swing direction Y between 19d and the tip end portion 17a of the filler material 17 can be substantially matched.

  For example, the distance in the direction perpendicular to the torch angle displacement axis L1 from the torch angle displacement axis L1 to the tip 19d of the electrode rod 19 is H1, and the distance from the filler material angular displacement axis L3 to the tip 17a of the filler material 17 is H1. The distance in the direction perpendicular to the filler metal angular displacement axis L3 is H5. Further, when the angle at which the torch support portion 23 is angularly displaced in the circumferential direction R1 around the torch angle displacement axis L1 from the standard state is φ1, the filler material guide support portion 26 is rotated around the melt material angular displacement axis L3. The angle of angular displacement in the other direction R2 is φ2. In this case, H1 · φ1≈H2 · φ2 is set. As a result, the tip end portion 17a of the filler material 17 substantially matches, so that the displacement amount of the tip end portion 19d of the electrode rod 19 and the tip end portion 17a of the filler material 17 in the swing direction Y substantially matches. be able to. In this embodiment, H1 = 5.9 mm, H5 = 50 mm, φ1 = 10 °, and φ2 = 1.2 °.

  As described above, the guide swing driving means 27 drives the filler material guide support portion 26 to swing around the melt material angular displacement axis L3 in conjunction with the swing angle displacement of the torch support portion 23. Accordingly, the filler material 17 can be swung according to the swing of the electrode rod 19, and even when the electrode rod 19 is swung, the tip end portion 19 d of the electrode rod 19 and the filler material 17 can be swung. The weaving welding can be performed while suppressing the positional deviation from the distal end portion 17a. Thereby, the unevenness of the filler material 17 can be prevented, and the bead height can be made flat. Moreover, it can prevent that the filler material 17 fuse | melted near groove wall surface is insufficient, and can improve joining quality.

  Further, the guide swing drive means 27 is realized by a power transmission mechanism that transmits the power of the torch swing drive means 24 to the filler material guide support portion 26. Accordingly, in order to angularly displace the filler material guide support portion 26 around the melt material angular displacement axis L3, a separate drive source is not required, and the filler material guide support portion 26 and the torch support are configured with a simple structure. The operation of the unit 23 can be linked. Further, the interlocking between the filler material 17 and the electrode rod 19 can be reliably interlocked without performing synchronization control or the like. As a result, it is possible to prevent malfunction of the interlocking and to prevent failure of the arc welding apparatus 20. Further, by separating the welding torch 22 and the filler material guide 25 in the joining direction, concentration of components can be prevented and the structure of the welding apparatus can be simplified. Further, in the present embodiment, by adjusting the swing angle displacement amount of the torch support portion 23 around the torch angle displacement axis L1, the swing amount of the tip 19d of the electrode rod 19 can be easily adjusted according to the groove width. Can be changed. Regardless of movement by the articulated robot 30, the amount of swing of the tip 19d of the electrode rod 19 can be changed.

  FIG. 10 is a block diagram showing a welding system 61 including the arc welding apparatus 20. The welding system 61 includes an arc welding device 20, a robot 30 that moves the arc welding device 20, and a control device 60 that controls the arc welding device 20 and the articulated robot 30. The control device 60 controls the arc welding device 20 in an integrated manner. In the present embodiment, the control device 60 gives an operation command to the articulated robot 30.

  The arc welding device 20 includes a welding power source device 50, an AVC device 51, a gas feeding device 52, a wire feeding device 53, a cooling water feeding device 59, the above-described swinging motor 33, and an encoder 54. And a laser sensor 55. The welding power source device 50, the gas feeding device 52, and the wire feeding device 53 are provided separately from the welding head 100. The AVC device 51, the swing motor 33, and the encoder 54 are formed integrally with the welding head 100.

  The welding power source device 50 is a DC power source or an AC power source, and is a device for generating a potential difference between the electrode rod 19 and the workpiece 18. The welding power supply device 50 generates a potential difference between one output terminal and the other output terminal. One output terminal and the electrode rod 19 mounted on the welding torch 22 are electrically connected by a welding cable. The other output terminal and the article 18 are electrically connected by a ground cable. As a result, a potential difference is generated between the workpiece 18 and the electrode rod 19, and an arc can be generated between the workpiece 18 and the tip 19 d of the electrode rod 19. Also, welding can be performed using heat generated when an arc is generated. The welding power supply device 50 generates an electric potential difference between the two output terminals when an arc generation command is given from the control device 60.

The AVC device 51 is automatic voltage control (Arc Voltage Controller, abbreviated as AVC), and compares the arc voltage when an arc is generated with a reference voltage set in the control device 60.
The tip 19d of the electrode rod 19 mounted on the welding torch 22 is moved up and down along the torch angle displacement axis L1 to adjust the arc length to be constant. In the present embodiment, the AVC device 51 is provided in the welding torch 22 as a unit. When performing arc welding along the direction in which the groove 16 extends, the position of the tip 19d of the electrode rod 19 is displaced by the AVC device 51, thereby suppressing welding defects caused by unevenness of the groove bottom surface 15 and making the bead appearance uniform. Can be achieved. The AVC device 51 adjusts the position of the tip 19d of the electrode rod 19 so that the arc length is constant when a drive command is given from the control device 60.

  The gas feeding device 52 includes a cylinder for compressing and storing the inert gas, a pressure regulator for decompressing and ejecting the inert gas in the cylinder, and a conduit for guiding the inert gas from the pressure regulator to the welding torch 22. A gas hose to be formed; and an on-off valve interposed in the gas hose. When the on-off valve opens the pipe, the inert gas flows down from the cylinder toward the welding torch 22. Moreover, the on-off valve closes the pipe line to prevent the inert gas from flowing down. The welding torch 22 injects the inert gas supplied from the gas supply device 52 from the opening of the welding torch 22 to the arc generation region. When the gas supply command is given from the control device 60, the gas supply device 52 opens the pipe line by the on-off valve and injects the inert gas from the opening of the welding torch 22.

  The wire feeding device 53 includes a wire reel around which a plurality of filler materials 17 are wound, and a feeder that feeds the filler material 17 wound around the wire reels. The filler material 17 is guided from the feeder to the filler material guide 25. The filler material 17 fed out by the feeder is guided by the filler material guide 25, and the tip portion 17 a of the filler material 17 is guided toward the tip portion 19 d of the electrode rod 19. When the wire feeding command is given from the control device 60, the wire feeding device 53 feeds the melt material 17 from the wire reel and feeds it to the melt material guide 25 by the feeder.

  The cooling water supply device 59 includes a cooling water source for supplying the cooling water, a circulation hose that guides the cooling water from the cooling water source to the welding torch 22 and guides the cooling water heated by the welding torch 22 to the discharge tank, And an on-off valve interposed in the circulation hose. When the on-off valve opens the pipe, the cooling water flows from the cooling water source toward the welding torch 22. Further, the on-off valve closes the pipe to prevent the cooling water from flowing down. The welding torch 22 is restrained from rising in temperature by introducing cooling water. The cooling water feeding device 59 is guided by the control device 60 from the control device 60 to open the pipe line by the on-off valve and guide the cooling water to the welding torch 22.

The control device 60 includes a storage circuit that stores a program indicating a control procedure and a database indicating control conditions, and an arithmetic circuit that executes the program stored in the storage circuit. The control device 60 is realized by a programmable controller, for example. The memory circuits are ROM (Read Only memory) and RAM (Random Access Memory).
The arithmetic circuit is realized by a CPU (Central Processing Unit).

  The swing motor 33 angularly displaces the output shaft 33a according to the angular displacement command given from the control device 60, and angularly displaces the torch support portion 23 around the torch angle displacement axis L1. The encoder 54 is detection means for detecting the angular displacement amount of the output shaft 33 a of the swing motor 33, and gives a signal indicating the detection result to the control device 60. The laser sensor 55 is a groove position detecting unit that detects a groove position, and gives a signal indicating the position of the groove position in the swing direction Y with respect to the laser sensor 55 to the control device 60. The laser sensor 55 also serves as a groove depth detection means for detecting the groove depth, and gives a signal indicating the position of the groove bottom surface 15 in the depth direction to the control device 60.

  FIG. 11 is a plan view showing the welding head 100. FIG. 12 is a left side view showing the welding head 100. The laser sensor 55 is provided on the welding head 100. The laser sensor 55 is fixed to the base 21 via the arm member 56. The laser sensor 55 and the arm member 56 are arranged so as not to hinder the swinging of the welding torch 22 and the filler material guide 25, and are fixed at a fixed position with respect to the base 21 regardless of the swinging of the welding torch 22. The The laser sensor 55 captures an image of a groove region that is located in front of the welding torch 22 and the filler material guide 25 in the joining direction X1. The control device 60 performs image processing on the information indicating the groove region imaged from the laser sensor 55, whereby the inner walls 14 a and 14 b of the groove with respect to the base 21, the center position in the width direction of the groove 16, and the groove bottom surface 15. Depth can be determined. The control device 60 can displace the torch angle displacement axis L <b> 1 in the swing direction along the groove 16 based on the signal given from the laser sensor 55.

  FIG. 13 is a right side view showing the welding head 100. The articulated robot 30 is realized by a 6-axis vertical articulated robot, and an end effector angular displacement axis L5 is set. The articulated robot 30 can rotate the base 21 around the end effector angular displacement axis L5. In the present embodiment, the wrist portion of the articulated robot 30 is connected to the base portion 21 via the connecting member 57. The articulated robot 30 connects the base 21 so that the end effector angular displacement axis L5 and the torch angular displacement axis L1 coincide. In addition, a shield member 58 that covers the arc generation region is fixed to the base portion 21. The shield member 58 is disposed on both sides of the swinging direction Y and the rearward direction X2 with respect to the welding torch 22 to cover the arc generation region. As a result, the arc generation region can be filled with an inert gas, and sparks from the arc can be prevented from being scattered outside the shield member 58.

  FIG. 14 is a flowchart showing the arc welding procedure of the control device 60. First, in step a0, when the groove 16 is formed in the workpiece 18 and the welding preparation for arc welding is completed, when an arc welding command is given by an operator or the like, the process proceeds to step a1 and the welding operation is performed. Start. The control device 60 executes the following operation by executing the welding program stored in the storage circuit.

  In step a1, the control device 60 gives a movement command to the articulated robot 30 and moves the welding head 100 to an initial position determined in advance by an operator or the like. The initial position is a position where the tip end portion 19 d of the electrode rod 19 is disposed in the groove 16 and the joining direction X of the base portion 21 is along the extending direction of the groove 16. When the welding head 100 moves to the initial position, the process proceeds to step a2.

  In step a <b> 2, the control device 60 gives a gas feed command to the gas feed device 52 and gives a coolant feed command to the coolant feed device 59. Next, an arc generation command is given to the welding power supply device 50 and a wire feed command is given to the wire feeding device 53 to generate an arc between the electrode rod 19 and the workpiece 18 and at the same time, The feeding of the material 17 is started. When arc welding is started in this way, the process proceeds to step a3.

  In step a <b> 3, the control device 60 moves the base portion 21 along the extending direction of the groove 16 by the articulated robot 30. At this time, the control device 60 gives a movement command to the articulated robot 30 in the swing direction in accordance with a signal given from the laser sensor 55, and arranges the torch angle displacement axis L1 at the center position of the groove 16 in the swing direction. Maintain the state. Further, the control device 60 obtains a swing displacement amount that prevents contact with the inner walls 14 a and 14 b of the groove 16 in accordance with a signal given from the laser sensor 55. The control device 60 gives a swing command to the swing motor 33 based on the detection result from the encoder 54 so as to swing the tip 19d of the electrode rod 19 by the calculated swing displacement amount.

  During the weaving welding, the control device 60 gives a drive command to the AVC device 51 to adjust the distance between the tip 19d of the electrode rod 19 and the groove bottom surface 15 so that the arc length is constant. As a result, weld defects due to the unevenness of the groove bottom surface 15 can be suppressed, and the bead appearance can be made uniform. When weaving welding is thus started, the process proceeds to step a3.

  In step a <b> 3, the control device 60 determines whether or not the welding head 100 circulates the workpiece 18 and has stacked the filler material 17 from the groove bottom surface 15 to a predetermined rough finish height. For example, if it is determined that the initial position has been turned a predetermined number of times, or if it is determined by the laser sensor 55 that the height of the filler material 17 of the groove 16 has reached the rough finish height, the process proceeds to step a4. Control device 60 repeats step a3 until it is determined that multiple layers of filler material 17 are provided from groove bottom surface 15 to a predetermined height. For example, the rough finish height is set to be substantially the same as the depth dimension of the groove 16.

  In step a4, the control device 60 performs finish welding control. Specifically, the control device 60 controls the wire feeding device 53 so that the multi-layer height of the filler material 17 is equal to or higher than the final finish height H10 over the extending direction of the groove 16. FIG. 15 is a graph for explaining the control of the wire feeding device 53 during finishing. The horizontal axis in FIG. 15 indicates the movement position of the welding head 100. The vertical axis in FIG. 15 is a diagram showing the multilayer height of the filler material 17 at each position of the welding head 100. In step a4, when the control device 60 continues the step a3 to perform the weaving welding and moves the welding head 100, a period in which the height of the multilayer pile of the filler material 17 is equal to or higher than the final finishing height H10. For W1, the wire feeding by the wire feeding device 53 is stopped. In addition, during the period W2 in which the height of the multilayer of the filler material 17 is less than the final finish height H10, the wire feeding device 53 performs wire feeding. The control device 60 can calculate the height of the multilayer pile of the filler material 17 based on a signal from the laser sensor 55. In this way, when the control device 60 determines that the multi-layer height of the filler material 17 is equal to or greater than the final finishing height H10 in the extending direction of the groove 16, the process proceeds to step a5.

  In step a5, the control device 60 gives an arc stop command to the welding power source device 50 to end the generation of the arc, and gives a drive stop command to the AVC device 51 and the swinging motor 33. Further, the control device 60 gives a feed end command to each of the gas feeding device 52, the wire feeding device 53, and the cooling water feeding device 59. When an end command is given to each device in this way, the process proceeds to step a6. In step a6, the control device 60 moves the welding head 100 to a predetermined standby position by the multi-joint robot 30, proceeds to step a7, and ends the welding operation.

  As described above, in the present embodiment, by moving the welding head 100 by the multi-joint robot 30, the welding head 100 can be moved to an arbitrary position and posture, and the number of scenes that can be welded can be increased. . In the present embodiment, the articulated robot 30 can perform weaving welding only by moving the base 21 of the welding head 100 along the groove 16, and moves the wrist of the articulated robot in the swinging direction. Compared with the case where it is made, the inertia force which arises in weaving is small, high-speed rocking | fluctuation is possible, and weaving welding can be performed with high precision. Further, arc welding can be performed even in a narrow groove.

  In addition, the laser sensor 55 is used to detect the relative position of the base 21 in the swing direction with respect to the groove position. The control device 60 controls the articulated robot 30 based on the detection result of the laser sensor 55. Accordingly, the articulated robot 30 can move the base 21 so as to correct the deviation of the base 21 with respect to the groove 16. As a result, it is possible to prevent the electrode rod 19 from interfering with the workpiece 18 even when the formation accuracy of the groove 16 is low during the weaving welding.

  Further, by detecting the groove depth using the laser sensor 55, control according to the detection result can be performed. For example, the joining quality can be further improved by changing the welding conditions such as the supply amount change of the filler material 17, the arc voltage change, and the height change of the base 21 based on the groove depth. In the present embodiment, in the finish welding process in step a4, according to the multi-layer height of the filler material 17, by changing the presence or absence of feeding of the filler material 17, over the extending direction of the groove 16, It is possible to suppress the variation in the multilayer height of the filler material 17, improve the aesthetics and the bonding strength, and improve the bonding quality. Further, in the present embodiment, the configuration of the arc welding apparatus can be simplified by using the laser sensor 55 as compared with the case where the groove position detecting means and the groove depth detecting means are separately prepared. .

  Further, in the present embodiment, the laser sensor 55 is fixed to the base portion 21 regardless of the swinging of the welding torch 22, so that the laser sensor 55 is not shaken with the swinging of the welding torch 22, and the groove is accurately provided. The position and depth of the groove portion can be determined. In the present embodiment, the end effector angular displacement axis L5 set on the wrist of the robot and the torch angle displacement axis L1 are set coaxially so that the coordinates set at the wrist position of the robot and the intersection point are set. The coordinates of P1 can be easily associated, and the control device 60 can easily calculate the movement position of the robot 30.

  In the present embodiment, as a finishing process, the presence or absence of feeding of the filler material is switched according to the height of the multi-layer pile of the filler material 17 while weaving, but the filler material 17 is not subjected to weaving. Depending on the height of the multi-layer, the presence or absence of feeding of the filler material may be switched. Further, the finishing process may be performed during the circulation by the welding head 100. Therefore, the finishing process and the normal weaving welding process may be repeated alternately. As a result, the multilayer height of the filler material 17 can be made uniform.

The above-described embodiment is merely an example of the present invention, and the configuration can be changed within the scope of the invention. For example, in the present embodiment, the groove is a V-shaped groove, but other groove shapes may be used. For example, even if it is an X-shaped groove, the same effect can be obtained. Moreover, although welding was performed on the cylindrical workpiece 18, even the plate-like workpiece 18 can be arc-welded. In the present embodiment, TIG welding is exemplified, but MIG (Metal Inert
Gas) welding may be used. Moreover, it does not limit about the kind of electrode rod, filler material, and inert gas. Furthermore, simple arc welding that does not use an inert gas may be used. Further, the heated filler material 17 may be fed to the tip 19 d of the electrode rod 19.

  Moreover, each dimension of the illustrated arc joining apparatus in the present embodiment is an example, and other dimensions may be used. Moreover, in this Embodiment, although the presence or absence of feeding of the filler material 17 was changed according to the height of the multilayer pile of the filler material 17, the feeding speed of the filler material 17 may be changed. When the height is low, the feeding speed of the filler material 17 may be made higher than when the height is high. In the present embodiment, the servo motor is used to swing the torch support portion 23, but other driving means may be used. For example, a reciprocating drive device such as an air cylinder may be used. In the present embodiment, the filler material guide 25 is angularly driven using the power of the torch swing driving means 24, but the filler material is driven using a drive means different from the torch swing driving means 24. The guide 25 may be angularly displaced. The guide rocking drive means 27 shown in the present embodiment uses the power of the torch rocking drive means 24 by another link mechanism using a cam follower and a rail to move the filler material guide 25. It may be displaced.

  Further, in the present embodiment, the arc welding apparatus 20 includes other than the welding head 100, but the welding head 100 may be a welding apparatus main body. Further, although the welding head 100 is moved to an arbitrary position and posture by the articulated robot 30, the present invention is not limited to this, and the same effect can be obtained by using other transfer devices as long as the welding head 100 can be transferred. Can be obtained.

It is a front view which shows the welding head 100 of the arc welding apparatus 20 which is one Embodiment of this invention. 2 is an enlarged front view showing a part of a welding head 100. FIG. 4 is a cross-sectional view showing a torch swing drive means 24. FIG. It is a perspective view which shows two to-be-joined members 18a and 18b which comprise the to-be-joined object 18. FIG. FIG. 5 is a cross-sectional view showing the groove 16 of the workpiece 18 from the front X1 in the joining direction to the rear X2 in the joining direction in order to explain the waving operation. 4 is a plan view showing a movement locus 37 of the torch angle displacement axis L1 and a movement locus 38 of the tip 19d of the electrode rod 19. FIG. It is sectional drawing which shows the state which piled up the melted filler material and multilayered the groove | channel 16 of the to-be-joined object 18. FIG. FIG. 3 is a cross-sectional view schematically showing the operation of the guide swing driving means 27 when viewed from the section line S8-S8 in FIG. It is a figure which shows operation | movement of the electrode rod 19 and the filler material 17 seeing from the S9-S9 cut surface line of FIG. 1 is a block diagram showing a welding system 61 including an arc welding apparatus 20. 1 is a plan view showing a welding head 100. FIG. 1 is a left side view showing a welding head 100. FIG. 3 is a right side view showing the welding head 100. FIG. 5 is a flowchart showing an arc welding procedure of the control device 60. It is a graph for demonstrating control of the wire feeder 53 at the time of finishing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 19 Electrode rod 19c Protruding part 19d Electrode rod tip 20 Arc welding device 21 Base 22 Welding torch 23 Torch support 24 Torch swing drive means 25 Filler material guide 26 Filler material guide support 27 Guide swing drive means 30 Articulated robot L1 Torch angle displacement axis L2 Electrode axis P1 Intersection

Claims (7)

A base fixed to the robot and set with a predetermined torch angle displacement axis; and
With the tip of the electrode rod protruding, a welding torch for detachably attaching the electrode rod;
The welding torch is supported so that the center axis of the electrode rod attached to the welding torch is inclined with respect to the torch angle displacement axis, connected to the base so as to be able to be displaced by a swing angle around the torch angle displacement axis. A torch support to perform,
Including a torch swing driving means for driving the torch support portion to swing at a swing angle about the torch angle displacement axis,
An arc welding apparatus, wherein an intersection of a center axis of the electrode rod and the torch angle displacement axis is disposed at a protruding portion of the electrode rod protruding from the welding torch.   2. The arc welding apparatus according to claim 1, wherein the welding torch is mounted coaxially with a linear bar-like electrode bar having a tapered tip. A non-melting type arc welding apparatus,
A filler material guide for guiding the filler material to an area near the electrode rod attached to the welding torch;
A filler material guide support portion that is connected to the base portion so as to be capable of rocking angle displacement around a filler material angular displacement axis extending parallel to the torch angle displacement axis, and supports a filler material guide;
The filler material guide support part is linked to the swing angle displacement of the torch support part so that the filler material guided by the filler material guides to the electrode rod attached to the welding torch. 3. The arc welding apparatus according to claim 1, further comprising guide swing driving means for driving swing angle displacement around the axis.   The guide swing drive means is realized by a power transmission mechanism that transmits the power of the torch swing drive means and drives the filler material guide support portion to swing angle about the melt material angular displacement axis. The arc welding apparatus according to claim 3.   5. The groove position detecting means connected to the base portion for detecting a relative position of the base portion with respect to the groove position and providing a detection result to the robot. 6. Arc welding equipment.   The arc welding apparatus according to any one of claims 1 to 5, further comprising a groove depth detecting unit connected to the base and detecting a depth of a groove position.   A welding facility comprising: the arc welding apparatus according to any one of claims 1 to 6; and a robot for displacing the arc welding apparatus.

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