JP2010036241A - Torch for tandem arc welding and welding equipment with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torch for tandem arc welding in which an inner face of a nozzle is easily cleaned. <P>SOLUTION: In the welding torch 18 for tandem arc welding, two electrodes equipped inside a torch body 1 are housed in one nozzle 2. The nozzle 2 include a plurality of nozzle bodies 6 allowing the electrodes to be exposed by opening the distal ends of the nozzle bodies outward. The torch body 1 has an opening/closing mechanism 11 that opens the distal ends of each nozzle bodies 6 outward. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a tandem arc welding torch, and more particularly to a tandem arc welding torch capable of cleaning the inner surface of a nozzle and a welding apparatus including the same.

  Conventionally, arc welding has been used for welding various plate materials. In recent years, in the field of heavy plate welding such as construction machinery and bridges, further improvement in the efficiency and automation of welding has been achieved to further reduce costs. Therefore, tandem arc welding is performed by a gas shield welding method using a welding robot.

  In this tandem arc welding, a leading electrode and a trailing electrode made of a solid wire for welding are arranged with a predetermined distance between them in the welding direction, and an arc is generated from each electrode while supplying a shielding gas from a nozzle. One arc is formed by one arc and welding is performed. Compared with arc welding using a single electrode, the amount of welding is significantly larger, and highly efficient welding is possible.

  As the nozzle of this tandem arc welding torch, a water-cooled nozzle is usually employed because it is at a high temperature because it is located in the vicinity of the arc of the electrode used at 500 A or more. In the water-cooled nozzle, a water passage such as a water hose is formed between the nozzle and the torch body, and is connected by a coupling or the like.

  Moreover, since this nozzle is located in the vicinity of the arc and becomes high temperature, scattered spatter tends to adhere strongly to the inner surface of the nozzle. Thus, the sputters adhering to the inner surface of the nozzle disturb the flow of the shielding gas. Therefore, in order to ensure sufficient shielding performance, it is necessary to clean the inner surface of the nozzle and remove the spatter.

  In addition, as a conventional technique related to this type of tandem arc welding, the sum of the welding current density of the leading electrode and the welding current density of the succeeding electrode, the electrode protrusion length of each electrode, etc. There are few, and the stability of a molten pool is good and bead shape is good (for example, refer patent document 1).

Further, as a conventional technique related to this type of tandem arc welding torch, there is a welding torch assembly that can be used as a torch for MIG welding or TIG welding without replacing the torch body (for example, Patent Document 2).
JP 2003-53545 A JP 2007-237247 A

  By the way, as described above, as an automatic cleaning device for removing spatter adhering to the inner surface of the nozzle, a nozzle cleaning method is mainly adopted in which a sputter is removed by rotating a cylindrical blade against the inner surface of the nozzle. Yes.

  However, the nozzle of the tandem arc welding torch has an oblong cylindrical body for accommodating the two electrodes, the leading electrode and the trailing electrode, and the nozzle opening is large, so that it is stable. In order to obtain a shield gas flow, the inside of the nozzle is greatly expanded compared to the tip. In addition, a planar portion exists on the inner surface of the nozzle. Therefore, it is difficult to accurately move the cylindrical blade along the inner surface of the nozzle, and the sputter of the circular portion of the inner surface of the nozzle can be removed, but the sputter of the flat portion remains, and the sputter of the inner surface of the nozzle is completely removed. Can not do it.

  As another cleaning method, there is a method using a magnetic suction type nozzle cleaner or a compressed air blowing type nozzle cleaner used for torch cleaning such as thin plate welding which is welded using a small current. However, in the case of high-temperature tandem arc welding torch nozzles that are welded using a large current, spatter adheres firmly, so that a magnetic suction type or compressed air blowing type nozzle cleaner can provide a sufficient cleaning effect. I can't.

  Therefore, the conventional sputter cleaning method cannot obtain a sufficient cleaning effect on the inner surface of the nozzle, and the spatter remaining on the inner surface of the nozzle may disturb the flow of the shield gas, leading to deterioration in welding quality.

  On the other hand, a nozzle replacement method is also conceivable in which the nozzle is replaced with a cleaned nozzle when the nozzle needs to be cleaned so that the nozzle is not cleaned during the welding operation as described above. However, as described above, since the nozzle of the tandem arc welding torch has a water cooling structure, a water channel such as a coupling formed between the nozzle and the torch body is attached and detached in order to adopt the nozzle replacement method. It must be done and cannot be easily replaced. In addition, the water-cooled nozzle is very expensive, and it is necessary to prepare a large number of replacement nozzles for an unattended operation for a long time (for example, an automated factory that requires replacement every 30 minutes). Realization is difficult because of the cost.

  Therefore, an object of the present invention is to provide a tandem arc welding torch that can easily clean an inner surface of a nozzle and a welding apparatus including the torch.

  In order to achieve the above object, a tandem arc welding torch according to the present invention is a tandem arc welding torch in which two electrodes provided in a torch body are accommodated in one nozzle, and the nozzle has a tip portion. It has a plurality of nozzle bodies that can be opened outward to expose the electrodes, and the torch body has an opening / closing mechanism that opens the tip of each nozzle body outward. Features. According to such a welding torch, when removing spatter and the like adhering to the inner surface of the nozzle body, the inner surface of the nozzle body can be exposed outwardly by opening the tip of the nozzle body outward. Therefore, the inner surface of the nozzle body can be easily cleaned with a cleaning tool such as a rotating brush, and the cleaning can be stably performed so that the adhering spatter is removed and the rectification of the shield gas is maintained.

  The nozzle body has an upper end portion rotatably supported by the torch body, and the opening / closing mechanism includes a rod that moves in an axial direction of the torch body, and a tip portion of the nozzle body that is moved by the movement of the rod. You may have a link which rotates outward and opens. If it does in this way, the nozzle body rotatably supported by the torch main body can be opened and closed stably by the opening and closing mechanism combining the rod and the link.

  Further, the upper end of the nozzle body is rotatably supported by the torch body, and the opening / closing mechanism includes a rack that moves in an axial direction of the torch body, and a support portion of the nozzle body that is moved by the movement of the rack. You may have the pinion rotated and open | released outward. In this way, the nozzle body rotatably supported by the torch body can be stably opened and closed by the rack and pinion opening and closing mechanism.

  Moreover, you may comprise the latching | locking part which restrict | limits the opening angle of the said nozzle body by a predetermined angle. In this way, the nozzle body can be locked in a state where the nozzle body is opened at a predetermined angle, so that the reaction force at the time of cleaning the inner surface of the nozzle body can be stably cleaned while structurally supported.

  Furthermore, the inside of the nozzle body and the torch body are provided with a cooling water passage, the support portion of the nozzle body has a hinge structure, and the cooling water passage of the torch body and the cooling water passage of the nozzle body are provided in the hinge structure. A swivel joint for communication may be incorporated. If it does in this way, cooling water can be supplied and discharged to the cooling water channel of the nozzle body which can be opened and closed using the swivel joint built in the hinge structure.

  The hinge structure has a plurality of hinge portions that support the upper end portion of the nozzle body, and one of the plurality of hinge portions is connected to an inlet side swivel joint or a cooling member that communicates with a cooling water passage inlet of the nozzle body. An outlet side swivel joint communicating with the water passage outlet may be provided to define the flow direction of the cooling water. In this way, the cooling water is supplied to the cooling water passage from a part of the hinge portion that supports the nozzle body, and this cooling water is discharged from the other cooling water passage to the other hinge portion. The cooling effect of the nozzle body can be improved by regulating the flow of the nozzle.

  On the other hand, a tandem arc welding apparatus according to the present invention is a tandem arc welding apparatus including any one of the above tandem arc welding torches, and a brush for cleaning the inner surface of the nozzle body, and a drive for cleaning the brush. A control device for cleaning the inner surface of the nozzle body by moving the inner surface of the nozzle body to a brush position of the cleaning device in a state where the nozzle body is opened outward. It was made to be characterized. According to such a welding apparatus, for example, a cleaning device having a disc-shaped brush and a driving device (such as an electric motor) for rotating the disc-shaped brush is arranged around the tandem arc welding apparatus, and the torch is controlled by the control program operation of the welding apparatus. Sputtering can be completely removed automatically by opening the nozzle body outward and dividing the inner surface of the nozzle several times and applying it to the brush of the cleaning device. In addition, it is possible to eliminate the manual work and reduce the work around the welding apparatus of the worker, and it is possible to reduce the manufacturing cost by extending the unmanned operation time. By adopting a welding robot as such a welding apparatus, it becomes possible to clean the nozzle inner surface by facing the brush of the cleaning apparatus by various operations.

  According to the present invention, since the nozzle inner surface is exposed to the outside by removing the nozzle tip portion outwardly by means as described above, the adhered spatter and the like can be easily removed. It becomes possible to stabilize the rectification of gas and stabilize the welding quality.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a tandem arc welding torch according to a first embodiment of the present invention, FIG. 2 is a perspective view showing an intermediate open state of the nozzle shown in FIG. 1, and FIG. FIG. 4 is a side view showing the fully open state of the nozzle shown in FIG. 3. The state shown in FIG. 1 is a state during welding, and the state shown in FIG. 3 is a state during cleaning. In the specification and claims, the state viewed from the arrow I shown in the figure is the front, and in the state facing the front, the up and down direction, the left and right direction, and the front and rear direction are referred to. The direction is called the axial direction. Further, the tip portion of the tandem arc welding torch 18 is referred to as a torch body 1, and this torch body portion is illustrated and described.

  As shown in FIG. 1, a nozzle 2 is provided at the tip of the torch body 1, and the tips of two power feed chips 3 (electrodes) protrude from the nozzle 2. The nozzle 2 is formed in a substantially oval cross section so as to house two power supply chips 3. By covering the periphery of the two power supply chips 3 with the nozzle 2, the nozzle 2 is directed toward the periphery of the power supply chip 3. Thus, stable sealing of the arc welded portion is achieved with a shielding gas such as carbon dioxide gas supplied into the nozzle 2 or a mixed gas of argon and carbon dioxide. The inner surface of the nozzle 2 is formed to have a smooth surface so as to obtain a stable shield gas flow, and the tip of the nozzle 2 is ejected from the gap between the tip of the nozzle 2 and the power supply tip 3 toward the periphery of the power supply tip 3. Is formed to be narrow. A torch neck 4 for supplying a welding current and a welding wire separately to the two power supply tips 3 is connected to the upper portion of the torch body 1.

  In this embodiment, the nozzle 2 provided in the torch main body 1 is constituted by a combination of a nozzle body 6 having a two-divided structure in which a mating surface 5 is provided at the center in the front-rear direction. These nozzle bodies 6 are supported on the torch main body 1 by hinge portions 7 having hinge structures at the upper ends. The hinge portion 7 is provided between the upper hinge member 8 fixed to the lower end portion of the torch body 1, the lower hinge member 9 fixed to the upper end portion of the nozzle body 6, and the hinge members 8, 9. And a support shaft 10 serving as a rotation center.

  An opening / closing mechanism 11 that opens the nozzle body 6 outward is provided on the torch body 1 side. The opening / closing mechanism 11 of this embodiment is configured using a rod 12 and a link 13. The rod 12 extends downward from above, branches in the front-rear direction above the torch body 1, and extends downward toward the front and rear hinges 7. The rod 12 is moved in the vertical direction by a driving machine (not shown) constituted by an actuator such as an air cylinder provided above the torch body 1.

  Further, the link 13 is provided between the lower end of the rod 12 and the lower hinge member 9. The end of the link 13 is connected to the lower end of the rod 12 and a bracket 14 provided on the lower hinge member 9 with a pin 15.

  Further, a locking member 16 (stopper) for restricting the opening angle of the nozzle body 6 is provided on a side portion of the lower hinge member 9. The locking material 16 opens the nozzle body 6 outward. In contact with the upper hinge member 8, the opening angle of the nozzle body 6 is limited to a predetermined angle.

  According to such an opening / closing mechanism 11, when the rods 12 are pressed downward to close both nozzle bodies 6 inward, the mating surfaces 5 of these nozzle bodies 6 come into close contact to form an integral nozzle 2. be able to.

  As shown in FIG. 2, according to the opening / closing mechanism 11, when the rod 12 is moved upward, an upward force is applied to the bracket 14 of the lower hinge member 9 by the link 13 connected to the lower end, thereby lowering the lower hinge. The member 9 rotates about the support shaft 10 and the nozzle body 6 is opened outward. FIG. 2 shows a state in which the nozzle body 6 is being opened.

  As shown in FIG. 3, when the rod 12 is further moved upward from the state shown in FIG. 2, the locking member 16 provided on the side of the lower hinge member 9 comes into contact with the upper hinge member 8, The rotation for opening the nozzle body 6 outward stops. This state is a state in which the nozzle body 6 is held at a predetermined angle. As shown in FIG. 4, in this example, both nozzle bodies 6 are kept open at an opening angle of about 150 °. When the nozzle body 6 is opened outward until this state, the nozzle inner surface 17 can be exposed outward.

  In this way, the nozzle inner surface 17 is exposed outwardly and the opening angle thereof is maintained by the locking member 16, so that the nozzle body pressing force during the subsequent nozzle inner surface cleaning is supported structurally and stably. The inner surface cleaning 6 can be stably and reliably performed.

  According to the tandem arc welding torch 18 configured as described above, if the nozzle body 6 is opened outward after tandem arc welding for a predetermined time, the nozzle inner surface 17 can be easily formed by a cleaning tool such as a disk-shaped brush. Therefore, it is possible to reliably remove spatter and the like adhering to the nozzle inner surface 17.

  That is, the tandem arc welding torch 18 is formed by forming the nozzle 2 with the nozzle body 6 having a divided structure in which the tip end portion opens and closes, and is provided with the opening / closing mechanism 11 for opening and closing the nozzle body 6 to clean the nozzle tip portion during nozzle cleaning. The nozzle inner surface 17 can be exposed outward by opening the nozzle outward, so that the nozzle inner surface 17 can be cleaned with a brush, or a disk-shaped brush or the like installed outside can be driven with a drive machine (electric motor, etc.) Cleaning can be easily performed using a rotating nozzle cleaning device, and spatters and the like that are firmly attached can be reliably removed by mechanical cleaning. And since the whole nozzle inner surface 17 is exposed outward, sufficient cleaning effect is acquired over the whole nozzle inner surface. The automatic cleaning of the nozzle inner surface 17 will be described with reference to FIG.

  After cleaning to remove spatter and the like, the rod 12 is moved downward, whereby the tip of the nozzle body 6 is rotated inward via the link 13 to bring the mating surface 5 into close contact with each other. A typical nozzle 2 can be formed.

  As described above, according to the tandem arc welding torch 18, the nozzle inner surface 17 is exposed outwardly, and the cleaning operation for easily removing spatter and the like that has not been sufficiently removed can be performed. Therefore, the shield gas is stably rectified, and the quality of the weld metal can be stabilized.

  FIG. 5 is a perspective view showing a tandem arc welding torch according to the second embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. This embodiment is provided with an opening / closing mechanism 21 different from that of the first embodiment, and the opening / closing mechanism 21 of this embodiment is provided in a rack 22 that is moved up and down and in the nozzle body 6. A rack and pinion mechanism having a pinion 23 is provided. In this embodiment, the description of the power supply chip (electrode) and the like is omitted, and the upper part of the torch body 1 is shown in a simplified manner.

  As shown in the figure, the torch body 1 is provided with a rack 22 that is moved in the vertical direction (axial direction S) by a driving machine (air cylinder or the like) (not shown) provided above the torch body 1. The rack 22 is provided so as to move in the vertical direction at a central portion in the front-rear direction on one side (right side) of the torch body 1. The rack 22 has teeth 24 with the same pitch on the front and rear.

  On the other hand, the support shaft 26 of the hinge portion 7 that rotatably supports the nozzle body 6 extends to one side of the torch main body 1 on which the rack 22 is provided. A pinion 23 having a tooth portion 25 that meshes with the tooth portion 24 is provided. The pinion 23 is coupled so as to rotate integrally with the support shaft 26. Further, the support shaft 26 is coupled to rotate integrally with the lower hinge member 9. Accordingly, the pinion 23 is rotated by moving the rack 22 downward, so that the two nozzle bodies 6 are both opened outward through the lower hinge member 9 with the support shaft 26 as the rotation center. It has become.

  Also with the tandem arc welding torch 28 of the second embodiment, when the rack 22 is moved downward during cleaning, the locking member 16 is attached to the torch body 1 with the nozzle body 6 opened at an angle of about 150 degrees. It can contact | abut to the upper hinge member 8, and can hold | maintain in that state (open state similar to FIG. 4). And the sputter | spatter etc. can be easily removed by cleaning the nozzle inner surface 17 (FIG. 4) of the state with mechanical means, such as a brush.

  FIG. 6 is a drawing showing a tandem arc welding torch according to a third embodiment of the present invention, where (a) is a perspective view and (b) is a cross-sectional view taken along the line VI-VI shown in (a). is there. The cross-sectional view of (b) shows the cross section of the swivel joint portion. In this embodiment, a nozzle 32 having a water cooling structure and a configuration for supplying cooling water W to the nozzle 32 are added to the torch body 31. The opening / closing mechanism of the nozzle 32 may be the same as or different from the first embodiment or the second embodiment described above, and is not limited. Also in this embodiment, the description of the power feeding chip (electrode) and the like is omitted, and the upper part of the torch body 31 is shown in a simplified manner.

  As shown in the figure, this nozzle 32 is also constituted by a nozzle body 34 having a two-part structure in which a mating surface 33 is provided at the center in the front-rear direction. Each nozzle body 34 has an upper end portion at a lower end portion of the torch body 31. Are supported by two hinge portions 38. The hinge portion 38 of this embodiment is provided separately on the left and right. In this embodiment, a locking member 44 that regulates the opening angle is provided on one of the hinge portions 38.

  Further, inside the two nozzle bodies 34, there is provided a cooling water passage 37 that extends from the two hinge portions 38 divided on the left and right sides to the tip of the nozzle body. In this embodiment, the nozzle body 34 is integrally coupled with the inner member 35 and the outer member 36 so that a cooling water passage 37 is formed between the inner member 35 and the outer member 36. ing. The cooling water passage 37 is formed by forming a concave portion having the same shape as the outer member 36 outside the inner member 35, and the outer surface is covered with the outer member 36 so that the concave portion becomes the cooling water passage 37. It is formed by. The cooling water passage 37 formed in this way has the same shape as that of the outer member 36 and is a passage through which water can be passed over a wide range up to the vicinity of the tip of the nozzle body 34.

  Both ends of the cooling water passage 37 communicate with water passages 39 provided on the nozzle body 34 side of the hinge portion 38, respectively. In the figure, the right side is the cooling water passage inlet and the left side is the cooling water passage outlet, which defines the flow direction of the cooling water. Although only the front nozzle body 34 is shown in the figure, a similar cooling water passage 37 is also provided in the rear nozzle body 34.

  The torch body 31 is connected with a water supply pipe 40 extending from the upper side of the figure, and has a bypass pipe 41 provided from the front side to the rear side of the figure and a drain pipe 42 extending upward from the rear side. Is provided. These water supply pipe 40, bypass pipe 41, and drain pipe 42 communicate with a water passage 45 provided on the torch body 31 side of the hinge portion 38.

  The hinge portion 38 is provided with a swivel joint 46 that connects the water passage 45 on the torch body 31 side and the water passage 39 on the nozzle body 34 side. The swivel joint 46 is provided on the support shaft 43 of the hinge portion 38 and maintains the communication state between the water passage 45 and the water passage 39 even when the support shaft 43 that rotates integrally with the nozzle body 34 is rotated. It is like that. The swivel joint 46 employs a general structure that forms a water passage that is connected to the fixed side and the rotating side via the support shaft 43, and a detailed description thereof is omitted.

  In this embodiment, the cooling water W supplied from a cooling water supply device (not shown) is supplied from the water supply pipe 40 to the front nozzle body 34 through the water passage 45 and the right hinge 38. The cooling water W that has passed through 37 and flows out of the left hinge portion 38 flows from the bypass pipe 41 to the rear left hinge portion (not shown) via the water passage 45, and from the rear hinge portion to the rear nozzle. It passes through the cooling water passage 37 (not shown) of the body 34 and exits from the right hinge part (not shown) to the drain pipe 42 and returns to the cooling water supply machine. The flow of the cooling water W is indicated by a dotted line in the figure.

  In this way, by providing the swivel joint 46 inside the hinge portion 38 that rotatably supports the nozzle body 34, the nozzle body 34 that opens outward can be opened and closed by supplying water to the cooling water passage 37 and the torch body 1. The communication state of the water passage that supplies / discharges the cooling water W between the pipe 40, the bypass pipe 41, and the drain pipe 42 is not affected. In addition, by incorporating a swivel joint in the hinge portion 38 that supports the nozzle body 34, the structure for opening and closing the nozzle body 34 is made compact so that the torch and the workpiece do not interfere with each other. In addition, since it is not necessary to detach the water-cooled nozzle itself when cleaning the inner surface of the nozzle body 34, the structure of the entire apparatus is not complicated and can be configured at low cost.

  FIG. 7 is a perspective view of the nozzle inner surface cleaning state in the most opened state of the nozzle shown in FIG. 3. In this figure, the tandem arc welding torch 18 according to the first embodiment will be described as an example. As the tandem arc welding apparatus provided with the tandem arc welding torch 18, for example, a welding apparatus that can be automatically operated by a robot program, such as a welding robot, is preferable. FIG. 7 shows the torch body portion of the tandem arc welding torch 18 provided at the arm tip of the welding robot, and will be described with the reference numerals of the first embodiment.

  As shown in the figure, the tandem arc welding apparatus is provided with a cleaning device 51 at a predetermined position for cleaning the inner surface 17 of the nozzle body 6 provided in the lower portion of the torch body 1. The cleaning device 51 includes a disc-shaped brush 52 that cleans the inner surface 17 of the nozzle body 6 and a drive unit 53 (for example, an electric motor (not shown)) that rotates the brush 52. The driving machine 53 is provided inside the cleaning device main body 54, and the brush 52 is rotatably provided on an upper portion of a column 55 erected upward from the upper portion of the cleaning device main body 54. A drive shaft 56 that transmits the driving force of the drive unit 53 is provided inside the support column 55, and the power of the drive shaft 56 disposed in the vertical direction is laterally transmitted to the upper end portion of the support column 55. A gear (not shown) that transmits power to the brush 52 that rotates about the axis of the direction is provided.

  The shape of the brush 52 is preferably a shape that follows the shape of the inner surface of the nozzle other than the disc shape. In addition, as the material of the brush 52, a material that can remove spatter and the like firmly attached, such as a metal brush, is used.

  According to the tandem arc welding apparatus as described above, when the nozzle needs to be cleaned, the torch body 1 is moved to the vicinity of the cleaning apparatus 51 according to a command from the robot program, and the nozzle body 6 is directed outward. In a state where the inner surface 17 is exposed outwardly, the predetermined opening angle is maintained by the locking member 16, the brush 52 of the cleaning device 51 is rotated, and the nozzle body 6 is moved to the position of the brush 52. The cleaning process of cleaning the inner surface 17 of the nozzle body 6 with the brush 52 can be performed. In cleaning the inner surface of the nozzle body 6, when performing nozzle cleaning after welding, the nozzle opening / closing mechanism 11 is operated as shown in FIGS. Then, the inner surface 17 of the nozzle body 6 is brought into contact with the brush 52 of the cleaning device 51 and cleaned by the robot program.

  The position of the nozzle body 6 to which the brush 52 of the cleaning device 51 is applied is adjusted by moving the position of the torch body 1 according to a command from the robot program, and the nozzle inner surface 17 is uniformly cleaned. For example, since the nozzle inner surface 17 is divided into several times by the robot program operation and applied to the brush 52, the brush contact surface of the nozzle inner surface 17 can be arbitrarily moved, so that the entire nozzle inner surface 17 has a sufficient cleaning effect. Can get to. Further, the axial direction S of the torch body 1 may be horizontal or may be applied to the brush 52 at an arbitrary angle. In addition, by applying a strong spatter removing means such as a metal brush to the brush 52, cleaning with a high sputter removing effect can be performed when the nozzle inner surface 17 is cleaned. Further, not only the nozzle inner surface 17 but also the spatter attached to the power feed tip 3 can be removed at the same time. In this way, it is possible to remove the spatter and the like adhering to the inner surface 17 of the nozzle 2 and clean it.

  When the sputter and the like of the nozzle inner surface 17 are removed and cleaned by a predetermined cleaning process, the torch body 1 is separated from the cleaning device 51 by a command from the robot program, and the nozzle body 6 is moved by the command from the robot program. Closed in the direction. Since the nozzle body 6 closed in this manner has a smooth surface from which the sputters and the like of the inner surface 17 are removed, the shield gas is rectified as designed, and tandem arc welding with stable welding quality is performed. be able to.

  Further, as described above, the operation of exposing the inner surface 17 of the nozzle body 6 to be exposed outward and cleaning can be automatically performed by being controlled by a control device (not shown) according to the robot program and the operation. It is possible to perform tandem arc welding for a long time without an operator, and the cost can be greatly reduced.

  In the above embodiment, the nozzle body 6 having a two-divided structure has been described as an example. However, a three-divided structure or the like may be used, and the number of divisions of the nozzle 2 is not limited to the above-described embodiment.

  Further, as the opening / closing mechanisms 11 and 21, the combination of the rod 12 and the link 13 and the combination of the rack 22 and the pinion 23 have been described as examples. However, these opening / closing mechanisms 11 and 21 also have other configurations. The present invention is not limited to the above-described embodiment.

  Furthermore, the above-described embodiment shows an example, and various modifications can be made without departing from the gist of the present invention, and the present invention is not limited to the above-described embodiment.

  The tandem arc welding torch according to the present invention can be used for an automatic welding robot or the like that performs tandem arc welding by a robot program.

1 is a perspective view showing a tandem arc welding torch according to a first embodiment of the present invention. It is a perspective view which shows the intermediate | middle open state of the nozzle shown in FIG. It is a perspective view which shows the most open state of the nozzle shown in FIG. It is a side view which shows the most open state of the nozzle shown in FIG. It is a perspective view which shows the torch for tandem arc welding which concerns on 2nd Embodiment of this invention. It is drawing which shows the torch for tandem arc welding concerning 3rd Embodiment of this invention, (a) is a perspective view, (b) is sectional drawing of the VI-VI arrow shown to (a). It is a perspective view of the nozzle inner surface cleaning state in the most open state of the nozzle shown in FIG.

Explanation of symbols

1 ... Torch body
2 ... Nozzle
5 ... Mating surface
6 ... Nozzle body
7 ... Hinge part
8 ... Upper hinge member
DESCRIPTION OF SYMBOLS 9 ... Lower hinge member 10 ... Supporting shaft 11 ... Opening / closing mechanism 12 ... Rod 13 ... Link 16 ... Locking material 17 ... Inner surface of nozzle 18 ... Torch for tandem arc welding 21 ... Opening / closing mechanism 22 ... Rack 23 ... Pinion 28 ... Tandem arc welding Torch 31 ... Torch body 32 ... Nozzle 34 ... Nozzle body 35 ... Inner member 36 ... Outer member 37 ... Cooling water passage 38 ... Hinge portion 39 ... Water passage 40 ... Water supply pipe 41 ... Bypass pipe 42 ... Drain pipe 45 ... Water passage 46 ... Swivel joint 51 ... Cleaning device 52 ... Brush 53 ... Driver

Claims (7)

A torch for tandem arc welding in which two electrodes provided in a torch body are housed in one nozzle,
The nozzle has a plurality of nozzle bodies capable of exposing the electrode by opening a tip portion outward.
The torch main body is provided with an opening / closing mechanism for opening a tip end portion of each nozzle body outwardly, wherein the torch body is a tandem arc welding torch. The nozzle body has an upper end supported rotatably on the torch body,
2. The opening / closing mechanism includes a rod that moves in an axial direction of the torch main body, and a link that rotates and opens the tip of the nozzle body by moving the rod. Tandem arc welding torch. The nozzle body has an upper end supported rotatably on the torch body,
2. The opening / closing mechanism includes a rack that moves in an axial direction of the torch body, and a pinion that pivots a support portion of the nozzle body to open outward by the movement of the rack. Tandem arc welding torch.   The tandem arc welding torch according to claim 2 or 3, further comprising a locking portion that limits an opening angle of the nozzle body by a predetermined angle. A cooling water passage is provided in the nozzle body and the torch body,
The support part of this nozzle body is made into a hinge structure, The swivel joint which connects the cooling water channel | path of the said torch main body and the cooling water channel | path of a nozzle body is incorporated in this hinge structure in any one of Claims 2-4 The tandem arc welding torch as described. The hinge structure has a plurality of hinge portions that support the upper end portion of the nozzle body,
Any one of the plurality of hinge portions is provided with an inlet-side swivel joint communicating with the cooling water passage inlet of the nozzle body or an outlet-side swivel joint communicating with the cooling water passage outlet to define the flow direction of the cooling water. Item 6. The tandem arc welding torch according to Item 5. A tandem arc welding apparatus comprising the tandem arc welding torch according to any one of claims 1 to 6,
A cleaning device having a brush for cleaning the inner surface of the nozzle body, and a driving device for cleaning the brush;
A tandem arc welding comprising a control device for cleaning the inner surface of the nozzle body by moving the inner surface of the nozzle body to a brush position of the cleaning device with the nozzle body opened outward. apparatus.

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