JP5974791B2 - Method for suppressing misalignment of welding position of automatic welding equipment - Google Patents

Description

  The present invention has a configuration in which a branch pipe welder capable of performing fillet welding of a branch pipe and a mother pipe while moving a welding torch over the entire circumference in the circumferential direction of the branch pipe is attached to the robot arm. The present invention relates to a welding target position shift prevention method for an automatic welding apparatus for preventing occurrence of a shift of a welding target position in an automatic welding apparatus.

  One type of header (heading) in a boiler or the like is a type in which a plurality of branch pipes are connected to the outer peripheral surface of the mother pipe in the circumferential direction and the longitudinal direction (axial direction).

  When manufacturing this type of header, a plurality of circumferentially arranged mother pipes at one circumferential position, for example, at the upper end position of the outer circumferential face, are arranged at a required interval in the longitudinal direction of the mother pipe. A branch pipe is welded and attached, and then the mother pipe is rotated at a required angle in the circumferential direction and then newly arranged at a position at the upper end side of the outer peripheral surface of the mother pipe at a required interval in the longitudinal direction. A method is often used in which a plurality of branch pipes are attached in the circumferential direction and the longitudinal direction of the outer peripheral surface of the mother pipe by welding and attaching a plurality of branch pipes, and then repeating the above procedure in sequence.

  Therefore, the welding work between the main pipe and the branch pipe at the time of manufacturing the header described above is automated using a robot equipped with a welding torch because it requires welding work in a narrow part that is difficult to access with a normal welding torch. There has been proposed an automatic welding apparatus which can be used.

  One of the automatic welding apparatuses of this type includes a horseshoe-type guide having a notch for externally fitting to a branch pipe to be welded, and a circumference held by the horseshoe-type guide and beyond the notch A structure in which a branch pipe welder comprising a ring gear having a cutout portion that can be operated, and a welding torch that is attached to the ring gear and can be operated circumferentially together with the ring gear is attached to a tip portion of a robot hand of a robot There is something to do.

  According to the automatic welding apparatus having such a configuration, when the position of the branch pipe to be welded temporarily attached to the mother pipe is detected by the sensor in advance, the robot hand operates according to the position of the branch pipe. The horseshoe type guide of the branch pipe welder is moved from a direction perpendicular to the longitudinal direction of the mother pipe, and the notch part of the horseshoe type guide and the notch part of the ring gear arranged in accordance therewith are connected to the branch pipe to be welded. Fit outside.

  Thereafter, the welding torch is moved circumferentially together with the ring gear around the branch pipe arranged inside the guide, and the welded portion between the branch pipe and the mother pipe is extended over the entire circumference. It can be welded.

  Further, in the automatic welding apparatus, the horseshoe-shaped guide of the branch pipe welder is supplied to the welding torch of the branch pipe welder in a state where the horseshoe guide is externally fitted to the branch pipe to be welded that is temporarily attached to the mother pipe. There has also been proposed an idea of performing touch sensing of the above-described branch pipe to be welded and a mother pipe located therebelow using a wire as a probe. From the result of this touch sensing, the position information of the tip of the robot hand controlled by the robot control board (robot controller) of the robot and the position of the welding torch in the branch pipe welder are determined. Based on the information on the circumferential movement position and the known data on the shape of the branch pipe welder and the protrusion amount of the wire, the position information on the branch pipe to be welded and the mother pipe existing below the branch pipe is obtained. , XYZ can be detected with respect to the coordinates in the three-axis directions, so that more accurate alignment can be performed (see, for example, Patent Document 1).

  Further, in the automatic welding apparatus having the same configuration as described above, when the inclination of the branch pipe is detected by the same touch sensing as described above, the axis of the circumferential operation of the welding torch is performed by the robot to which the branch pipe welder is attached. The idea of correcting a coordinate system having a coordinate axis at the center position so as to incline corresponding to the detected deviation of the inclination of the branch pipe has been proposed (see, for example, Patent Document 2).

JP 2011-173138 A JP 2011-255402 A

  The automatic welding apparatuses disclosed in Patent Documents 1 and 2 are capable of favorably welding a branch pipe to a mother pipe.

  By the way, in the above automatic welding apparatus, when welding the connection portion of the branch pipe with the mother pipe is performed over the entire circumference in the circumferential direction of the branch pipe by the circumferential operation of the welding torch in the branch pipe welder, It is necessary to perform the welding work while arranging the tip side so as to push it into the welding point.

  For this reason, the branch pipe welder cannot be arranged so that the center of the circumferential path of the welding torch is simply aligned with the axis of the branch pipe. When performing the welding operation by moving the torch circumferentially, it is necessary to adjust the position of the welding torch along the radial direction of the branch pipe by moving the entire branch pipe welder with the robot hand.

  In this case, for example, when there is a difference in operation start timing or operation speed between the circumferential operation of the welding torch in the branch pipe welder and the operation of the entire branch pipe welder by the robot hand, a deviation occurs in the welding target position. It is possible.

  Therefore, the present invention further develops the automatic welding apparatus shown in Patent Document 1 above, and welds the welded portion between the branch pipe and the mother pipe over the entire circumference in the circumferential direction of the branch pipe. It is an object of the present invention to provide a welding target position shift suppressing method for an automatic welding apparatus that can suppress the shift of the welding target position of the torch and further improve the welding quality.

  In order to solve the above-mentioned problem, the present invention, corresponding to claim 1, has a guide having a notch for externally fitting the branch pipe at the tip of the robot hand of the robot, and is held by the guide. An automatic welding apparatus having a branch pipe welder comprising a welding torch capable of circumferential operation beyond the notch, and a circumferential operation of the welding torch by the branch pipe welder, A circular movement of the entire branch pipe welder by a robot hand for placing the distal end portion so as to push the branch pipe into the weld location of the branch pipe and the main pipe, When performing a welding operation over the entire circumference of the pipe, preset a dividing point obtained by dividing a plurality of welding locations over the entire circumference in the circumferential direction of the branch pipe, and correspond to the dividing point. The position where the welding torch should be arranged in the branch pipe welder, and The position where the entire branch pipe welder should be arranged with the bot hand is set in advance, and when the welding operation reaches the division point, the position where the welding torch is arranged with the branch pipe welder corresponding to the division point; Automatic welding is performed so that the robot hand performs a positioning operation targeting the position where the entire branch pipe welder should be placed, and when the positioning operation of the welding torch and the entire branch pipe welder is completed, the subsequent welding operation is resumed. It is set as the welding aim position shift suppression method of an apparatus.

According to the welding aim displacement prevention method of the automatic welding apparatus of the present invention, the following excellent effects are exhibited.
(1) When welding the welded portion between the branch pipe and the main pipe over the entire circumference along the circumferential direction of the branch pipe, the time when the welding operation reaches a dividing point set at a midway position in the circumferential direction This eliminates the difference in operation start timing between the circumferential operation of the welding torch by the branch pipe welder and the operation of the entire branch pipe welder by the robot hand and the synchronization deviation due to the difference in the operation speed. By doing so, it is possible to eliminate the deviation of the welding target position.
(2) Thereby, in the welding operation over the entire circumference of the branch pipe, even if the welding target position is temporarily shifted while the welding torch is moved in the circumferential direction, the welding target position It is possible to prevent the deviation from affecting the entire welding operation over the entire circumference in the circumferential direction or the accumulation of deviations in the welding target position.
(3) Therefore, the welding target position shift prevention method of the automatic welding apparatus of the present invention can suppress the shift of the welding target position when performing a welding operation on the main pipe of the branch pipe, thereby improving the welding quality. Can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows one form of the automatic welding apparatus which applies the welding aim position shift prevention method of the automatic welding apparatus of this invention. It is a top view which expands and shows the branch pipe welder in the apparatus of FIG. It is a figure which shows an example of the control flow for implementing the welding aim position shift prevention method of an automatic welding apparatus with the welding machine control apparatus in the apparatus of FIG. 1, and a robot control board. FIG. 1 shows the operation of the entire branch pipe welding apparatus by a robot hand when performing a welding operation in the circumferential direction of the branch pipe with the apparatus of FIG. 1, (a) shows the state at the start of the welding work, (b) (c (D) (e) (f) (g) (h) is a schematic diagram showing a state in which the welding work is performed by advancing the welding torch 45 degrees in the circumferential direction after starting the welding work. . It is a schematic diagram which shows the position of the division | segmentation point set to the circumferential direction of a branch pipe with the apparatus of FIG. It is a figure which shows another example of the control flow for implementing the welding aim position shift prevention method of an automatic welding apparatus with the welding machine control apparatus in the apparatus of FIG. 1, and a robot control board. It is a schematic diagram which shows the automatic welding apparatus which applies the welding aim position shift prevention method of the automatic welding apparatus of other form of implementation of this invention. It is a figure which shows the control flow for implementing the welding aim position shift prevention method of an automatic welding apparatus with the robot control board in the apparatus of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 to FIG. 5 show one embodiment of the welding aim displacement prevention method of the automatic welding apparatus of the present invention, which is as follows.

  Here, first, the configuration of an automatic welding apparatus to which the present invention is applied will be described.

  The automatic welding apparatus is indicated by reference numeral I in FIG. 1 and is not shown along the longitudinal direction of the mother pipe 1 according to the attachment positions of the plurality of branch pipes 2 arranged and attached in the longitudinal direction of the mother pipe 1. A multi-joint robot provided so as to be movable by a moving mechanism is provided, and a branch pipe welder 4 is attached to the tip of a robot hand 3 of the robot.

  As shown in FIG. 2, the branch pipe welder 4 inserts the branch pipe 2 from the radial direction, and a horseshoe-type guide 5 having a notch 5 a that can be enclosed by inserting the branch pipe 2 from the radial direction. A ring gear 6 with a notch that is provided on the lower side of the horseshoe-type guide 5 and is rotatably supported beyond the notch 5a of the horseshoe-type guide 5, and the horseshoe-type guide 5 On the other hand, a drive mechanism 7 for rotating the ring gear 6 relatively is provided. A torch mounting member 8 fixed to the ring gear 6 is attached to the ring gear 6 in an arrangement having a notch 8a at the same position as the ring gear 6, and the tip (lower end) is attached to the torch mounting member 8. A welding torch 10 arranged so as to face the center side of the ring gear 6 is configured to be attached downward via a torch support block 9.

  As a result, the branch pipe welder 4 operates the robot hand 3 by operating the robot hand 3 in a state where the phase of the notch 6a of the ring gear 6 is matched with the phase of the notch 5a of the horseshoe-type guide 5. The pipe welder 4 is brought closer to the side of the branch pipe 2 that is temporarily fixed at the upper end side position of the outer peripheral surface of the mother pipe 1, and the notches 5a and 6a of the horseshoe-type guide 5 and the ring gear 6 are It can be fitted on the branch pipe 2. Further, with this arrangement, in the branch pipe welding machine 4, the welding torch 10 attached to the ring gear 6 via the torch mounting member 8 and the torch support block 9 is connected to the branch pipe 2 and the main pipe 1. It can arrange | position toward one place of the circumferential direction of the welding part.

  Therefore, the branch pipe welder 4 thereafter causes the ring gear 6 to move circumferentially by driving the drive mechanism 7, so that the welding torch 10 is moved around the branch pipe 2 together with the ring gear 6. The horseshoe guide 5 can be moved circumferentially beyond the notch 5a. As a result, the welded portion between the branch pipe 2 arranged inside the horseshoe-shaped guide 5 and the mother pipe 1 below the branch pipe 2 is circumferentially moved by the welding torch 10 that moves circumferentially around the branch pipe 2. The fillet can be welded over the entire circumference.

  A robot control panel (robot controller) 15 for controlling the entire articulated robot including the control of the robot hand 3 is connected to the articulated robot.

  The branch pipe welder 4 controls the entire branch pipe welder 4 including control of the circumferential operation of the welding torch 10 integrated with the ring gear 6 and control of welding processing by the welding torch 10. A welding machine control device 16 is connected.

  The robot control panel 15 and the welding machine control device 16 can perform mutual communication at a constant period or at a preset timing.

  Further, the electrode 11 (positive electrode in FIG. 1) 12a of the energization detection type touch sensor 12 is connected to the wire 11 supplied to the welding torch 10 of the branch pipe welding machine 4 through the energization line 13, The other end of the energization line 14 having one end connected to the other electrode (negative electrode in FIG. 1) 12 b of the touch sensor 12 is connected to the mother tube 1. Further, a contact detection signal from the touch sensor 12 can be input to the robot control panel 15. As a result, when the wire 11 of the welding torch 10 is used as a probe and the wire 11 contacts the mother pipe 1 or the branch pipe 2 to be welded that is temporarily attached to the mother pipe 1, The touch sensor 12 can detect contact between the two by energization.

  Therefore, in a state where the horseshoe-type guide 5 of the branch pipe welder 4 is externally fitted to the branch pipe 2 to be welded that is temporarily attached to the mother pipe 1, the wire 11 of the welding torch 10 is used as a probe. It becomes possible to detect contact with the branch pipe 2 to be welded and the mother pipe 1 located near the lower part thereof.

  Therefore, in the robot control panel 15, information on the position and orientation of the tip of the robot hand 3 controlled by the robot control panel 15 and the branch pipe welder 4 attached to the tip of the robot hand 3. Known data (geometric information) about the shape of the wire 11 and the protruding amount of the wire 11, and information on the circumferential operation position of the welding torch 10 in the branch pipe welder 4 input from the welder control device 16 Based on the above, the position information of the position where the wire 11 of the welding torch 10 in the branch pipe 2 or the main pipe 1 to be welded contacts can be detected with respect to the coordinates in the XYZ triaxial directions.

  In FIG. 1, for convenience of illustration, the description of the parts other than the tip of the robot hand 3 of the articulated robot and the components other than the horseshoe guide 5 and the welding torch 10 in the branch pipe welder 4 is omitted. It is. Moreover, the circular arc drawn with the dashed-dotted line in a figure shows the outline | summary of the track | orbit of the circumferential operation | movement of the said welding torch 10 (it is the same also in FIG. 7 mentioned later).

  Here, using FIG. 4 (a) (b) (c) (d) (e) (f) (g) (h), the main pipe of the branch pipe 2 by the welding torch 10 of the branch pipe welder 4 1 and a branch pipe welder to be carried out by the robot hand 3 (see FIG. 1) along with the circumferential motion of the welding torch 10 around the branch pipe 2 during the welding operation of the welding torch 10. The overall operation of 4 will be described. 4 (a), (b), (c), (d), (e), (f), (g), and (h), for convenience of illustration, the ring gear 6, the welding torch 10, and the drive mechanism 7 in the branch pipe welder 4 are shown. Description of components other than a part of is omitted. An arc drawn with a one-dot chain line in the figure shows an outline of the orbit of the circumferential operation of the welding torch 10, and a black dot in the figure shows the center t of the orbit of the welding torch 10. Further, the x mark in the figure indicates the center s of the branch pipe 2.

  First, for example, as shown in FIG. 4A, the horseshoe guide 5 (see FIG. 2) of the branch pipe welder 4 and the notches 5a and 6a of the ring gear 6 are externally fitted to the branch pipe 2. Then, when welding of the branch pipe 2 to the mother pipe 1 by the welding torch 10 is started, the trajectory of the circumferential operation of the welding torch 10 is changed by the robot hand 3 over the branch pipe welder 4 as a whole. A certain dimension in a direction in which the location where the welding torch 10 is disposed is close to the center s of the branch pipe 2 (upward in the drawing in FIG. 4A). Shift. Thereby, since the said welding torch 10 is arrange | positioned so that the front end side may be pushed into a welding location, the welding with respect to the mother pipe 1 of the said branch pipe 2 is started in this state.

  After the welding operation is started as shown in FIG. 4 (a), the branch pipe welder 4 moves the welding torch 10 to, for example, FIGS. 4 (b), (c), (d), (e), (f). ) (G) After passing through (h) in order, as shown in FIG. 4 (a), the branch pipe is moved with the ring gear 6 in the clockwise direction at a constant speed along the circumferential movement path. A welding operation is performed to weld 2 to the mother pipe 1 over the entire circumference in the circumferential direction.

  At the time of this welding operation, the robot hand 3 moves the entire branch pipe welder 4 in a direction in which the location where the welding torch 10 is arranged is always close to the center s of the branch pipe 2 (in the drawing, 4B, the upper right direction, FIG. 4C, the right direction, FIG. 4D, the lower right direction, FIG. 4E, the lower direction, FIG. 4F, the lower left direction, and FIG. ) In the left direction, in FIG. 4 (h) in the upper left direction, and in FIG. 4 (a) in the upper direction), the branch pipe welder 4 as a whole is arranged in a circle of the welding torch 10. It is continuously moved so as to draw a circle around a point eccentric from the center t of the orbit of the circumferential motion. Thus, the welding torch 10 is arranged so that the distal end side of the welding torch 10 is always pushed into the welding location while the welding operation of the branch pipe 2 to the mother pipe 1 is performed. is there.

  Next, the welding aim displacement prevention method of the automatic welding apparatus of the present invention applied to the automatic welding apparatus I having the above configuration will be described.

  In the automatic welding apparatus I, as described above, during the welding operation of the branch pipe 2 to the mother pipe 1, the circumferential operation of the welding torch 10 in the branch pipe welder 4 and the entire branch pipe welder 4 by the robot hand 3. The circular motion is performed simultaneously (synchronously).

  By the way, the circumferential operation of the welding torch 10 in the branch pipe welder 4 that is controlled by the welder control device, and the entire circle of the branch pipe welder 4 by the robot hand 3 controlled by the robot control panel 15. When the operation causes a synchronization shift due to a difference in operation start timing or a difference in operation speed, a shift occurs in the welding target position.

  Among these, the synchronization shift between the circumferential operation of the welding torch 10 due to the difference in the operation start timing and the circular operation of the entire branch pipe welder 4 by the robot hand 3 is related to the circumferential direction of the branch pipe 2. It continuously affects the welding quality from the welding start position to the welding end position.

  Further, the synchronization shift caused by the difference in operation speed between the circumferential operation of the welding torch 10 and the circular operation of the entire branch pipe welder 4 by the robot hand 3 is in the vicinity of the welding start position with respect to the welding quality. Although the influence is small, the influence on the welding quality increases as the welding operation proceeds in the circumferential direction.

  In view of the above points, in the welding aim displacement prevention method of the automatic welding apparatus of the present invention, when performing the welding operation in the circumferential direction of the branch pipe 2, welding for one round from the welding start point to the welding end point is performed. For the stroke, n (n is a natural number) dividing points for dividing into a plurality at equal intervals in the circumferential direction are set in advance, and the circumferential operation of the welding torch 10 and the branch pipe welder by the robot hand 3 are set. 4 When the welding progresses to the position of the set dividing point in the middle of the welding operation involving the entire circular movement, the welding torch 10 that causes the branch pipe welder 4 to perform a circumferential operation on the basis of the dividing point. And the position of the entire branch pipe welder 4n that is circularly operated by the robot hand 3 are positioned.

  Next, in order to carry out the welding target misalignment method of the automatic welding apparatus of the present invention, the robot control panel 15 and the welding machine control apparatus 16 are common to the positions where the circumferential direction of the branch pipe 2 is divided into a plurality of parts. It has a function that can set the dividing point. For example, when the position of the welding torch 10 shown in FIG. 4 (a) is used as a welding start point and a welding end point after one layer (one pass) of welding work in the circumferential direction is shown in FIG. As described above, with respect to the welding process from the welding start point to the welding end point, division points Pm (m = 1, 2, 3,... 7) are respectively set at positions obtained by dividing the circumferential direction of the branch pipe 2 into eight equal parts. It has a function.

  Further, the welding machine control device 16 should position the welding torch 10 on the circumferential motion trajectory by the branch pipe welding machine 4 at the time of welding at the position of each division point Pm. It has a function to calculate kika in advance.

  On the other hand, the robot control panel 15 performs a circular pipe welding machine 4 that causes the robot hand 3 to perform a circular motion according to the position at which the welding torch 10 is arranged at the time of welding at the position of each division point Pm. It has a function of calculating in advance in which position the whole should be placed.

  Further, when the welding machine controller 16 and the robot control panel 15 are subjected to welding work to the main pipe 1 over the entire circumference in the circumferential direction of the branch pipe 2 by the welding torch 10 of the branch pipe welder 4. In addition, when the welding point advances to each of the dividing points Pm, at that time, a function of performing mutual communication is provided, and the welding of the branch pipe welder 4 calculated corresponding to each of the dividing points Pm. The position where the torch 10 should be disposed on the circumferential motion trajectory and the position where the entire branch pipe welder 4 should be disposed by the robot hand 3 are provided with a function of quickly aligning each other.

  The robot control panel 15 detects the inclination of the branch pipe 2 by touch sensing using the wire 11 of the welding torch 10 as a probe as shown in Patent Document 2 described above. On the side of the robot hand 3 to which the branch pipe welder 4 is attached, a coordinate system having a coordinate axis at the axial center position of the circumferential operation of the welding torch 10 in the branch pipe welder 4 is represented by the detected inclination of the branch pipe 2. You may make it provide the function corrected so that it may incline according to deviation | shift amount.

  The control flow when the welding operation is performed by the robot control panel 15 and the welding machine control device 16 having the above functions may be as shown in FIG. 3A is a control flow of the welding machine control device 16, and B is a control flow of the robot control panel 15. FIG.

  That is, first, before starting the welding operation, in the welding machine control device 16, in addition to the welding conditions and the circumferential operation conditions of the welding torch 10 according to the welding conditions, The number of the division points Pm and the position where the welding torch 10 is to be disposed when welding the division points Pm are set (step A1).

  On the other hand, the robot control panel 15 sets the circular motion of the entire branch pipe welder 4 by the robot hand 3 according to the circumferential motion conditions of the welding torch 10 based on the welding conditions before starting the welding operation. Perform (Step B1).

  Next, in the welding machine control device 16 and the robot control panel 15, the corresponding branch pipe welding machine 4 and robot hand 3 are activated (step A2, step B2), respectively.

  The robot control panel 15 moves the branch pipe welder 4 by operating the robot hand 3 in accordance with the position of the branch pipe 2 to be welded temporarily fixed to the mother pipe 1 detected in advance by a sensor (not shown). Then, as shown in FIG. 4 (a), the horseshoe guide 5 (see FIG. 2) of the branch pipe welder 4 and the notches 5a and 6a of the ring gear 6 are fitted onto the branch pipe 2 (steps). B3).

  Next, the robot control panel 15 performs touch sensing using the wire 11 of the welding torch 10 as a probe (step B4), and according to the detected deviation amount of the inclination of the branch pipe 2, the branch pipe A coordinate system having a coordinate axis at the axial center position of the circumferential operation of the welding torch 10 in the welding machine 4 is corrected (step B5). Thereafter, the robot control panel 15 arranges the entire branch pipe welder 4 with the robot hand 3 at the time of welding at the position of each division point Pm according to the respective division points Pm set by the welding machine control device 16. The power position is calculated (step B6).

  Thereafter, the welding machine control device 16 and the robot control panel 15 start the welding operation (step A3, step B7). Thereby, in the said branch pipe welding machine 4, after the welding torch 10 starts welding about the welding location of the branch pipe 2 and the mother pipe 1 in the state shown to Fig.4 (a), this welding torch 10 In this way, a clockwise circumferential movement is started. At this time, the robot hand 3 starts the circular motion of the entire branch pipe welder 4 in response to the circumferential motion of the welding torch 10 in the branch pipe welder 4.

  Therefore, in the automatic welding apparatus I, the first layer (one pass) welding operation is started at the welded portion between the branch pipe 2 and the main pipe 1 (step B8).

  After starting the welding operation as described above, the first dividing point where the circumferential welding operation of the branch pipe 2 by the circumferential operation of the welding torch 10 is set in the circumferential direction of the branch pipe 2 When the process proceeds to Pm (m = 1) (step A4, step B9), the welding machine control device 16 and the robot control panel 15 communicate with each other, and then immediately, at the step A1 and step B6, the division point. Targeting the position where the welding torch 10 should be placed in the branch pipe welder 4 set (or calculated) for Pm (m = 1) and the position where the entire branch pipe welder 4 should be placed in the robot hand 3 Each positioning operation is performed (step A5, step B10). In this positioning operation, the circumferential operation of the welding torch 10 by the branch pipe welder 4 and the entire branch pipe welder 4 by the robot hand 3 (see FIG. 1) are arranged in the same arrangement as shown in FIG. Since the difference in the operation start timing from the circular motion and the synchronization shift due to the difference in the operation speed are eliminated, the deviation of the welding target position is once resolved.

  When the completion of the positioning operation is confirmed by mutual communication, the welding machine control device 16 and the robot control panel 15 perform the circumferential operation of the welding torch 10 by the branch pipe welder 4 and the branch pipe by the robot hand 3. The entire circular motion of the welding machine 4 is restarted so that the welding operation up to the next division point Pm (m = 2) (see FIG. 5) in the order set in the circumferential direction of the branch pipe 2 is restarted. It is.

  Thereafter, the welding machine control device 16 and the robot control panel 15 divide the dividing points Pm (m) in which the welding operation in the circumferential direction of the branch pipe 2 by the welding torch 10 is sequentially set in the circumferential direction of the branch pipe 2. = 2, 3, 4,...) (Step A6, step B11), the welding torch 10 is operated by the branch pipe welder 4 corresponding to the dividing point Pm in the same manner as in step A5 and step B10. The positioning operation is performed with the robot hand 3 as a target and the position where the entire branch pipe welder 4 is to be disposed (step A7, step B12). The process of resuming the welding operation toward the next division point Pm is repeated.

  As a result, at each division point Pm, the difference in operation start timing between the circumferential motion of the welding torch 10 by the branch pipe welder 4 and the circular motion of the entire branch pipe welder 4 by the robot hand 3 (see FIG. 1). In addition, since the synchronization shift due to the difference in the operation speed is eliminated, each time the welding operation reaches each division point Pm, the deviation of the welding target position is eliminated.

  The welding machine controller 16 and the robot control panel 15 reach the welding end point that coincides with the welding start point after the circumferential welding operation of the branch pipe 2 has passed all the division points Pm, and the branch pipe 2 When the welding operation over the entire circumference in the circumferential direction is finished, the first layer welding is finished (step A8, step B13).

  Thereafter, the welding machine control device 16 and the robot control panel 15 perform the N-th layer welding operation by the same processing as in the steps A3 to A8 and the steps B7 to B13, if necessary (step A9). , Step B14), when the welding work for all the set layers is completed (step A10, step B15), the welding operation is terminated.

  Thus, according to the welding aim displacement prevention method of the automatic welding apparatus of the present invention, the welded portion between the branch pipe 2 and the main pipe 1 is welded over the entire circumference along the circumferential direction of the branch pipe 2. In this case, the circumferential movement of the welding torch 10 by the branch pipe welder 4 and the circular movement of the entire branch pipe welder 4 by the robot hand 3 at the position of the dividing point Pm set at the middle position in the circumferential direction. It is possible to eliminate the deviation in synchronization due to the difference in operation start timing and the difference in operation speed, and to eliminate the deviation in the welding target position.

  Therefore, in the welding operation over the entire circumference in the circumferential direction of the branch pipe 2, even if the welding target position is temporarily shifted while the welding torch 10 is moved in the circumferential direction, the welding target position is shifted. It is possible to prevent the possibility of affecting the entire welding operation over the entire circumference in the circumferential direction or accumulating the deviation of the welding target position.

  Thereby, in the welding aim position prevention method of the automatic welding apparatus of this invention, when performing the welding operation | work with respect to the main pipe 1 of the branch pipe 2, the shift | offset | difference of a welding aim position can be suppressed, and improvement of welding quality is carried out. It becomes possible to plan.

  In the above embodiment, as shown in the control flow of the welding machine control device 16 and the robot control panel 15 in FIG. 3, it is detected by touch sensing (step B4) using the wire 11 of the welding torch 10 as a probe. The process of correcting the coordinate system having the coordinate axis at the axial center position of the circumferential operation of the welding torch 10 in the branch pipe welder 4 in accordance with the amount of inclination deviation of the branch pipe 2 is performed in step B5 of the robot control panel 15. However, as shown in FIG. 6, it may be performed by the welding machine control device 16 (step A11).

  Also in this case, the same processing as that in the embodiment of FIGS. 1 to 5 can be performed, and the same effect can be obtained.

  Next, FIG.7 and FIG.8 shows the application example of embodiment of FIG. 1 thru | or FIG. 5 as another form of implementation of this invention.

  That is, the automatic welding apparatus I to which the welding aim displacement prevention method of the automatic welding apparatus of the present embodiment is applied, as shown in FIG. 7, has the same configuration as that shown in FIG. The welding machine control device 16 for controlling the circumferential operation of the torch 10 is replaced with a configuration provided separately from the robot control panel 15, and the circumferential operation of the welding torch 10 in the branch pipe welding machine 4 is controlled. Therefore, the robot control panel 15a is provided with a function for this purpose.

  Specifically, the robot control panel 15a includes a welding machine control unit 17 integrally incorporated therein, and the welding machine control unit 17 performs a circumferential operation of the welding torch 10 in the branch pipe welding machine 4 by the welding machine control unit 17. Can be controlled.

  Other configurations are the same as those shown in FIGS. 1 to 5, and the same components are denoted by the same reference numerals.

  The control flow when the welding operation is performed by the robot control panel 15a having such a configuration may be as shown in FIG. Note that C in FIG. 8 is a control flow for controlling the branch pipe welder 4 by the welding machine controller 17 of the robot control panel 15a, and Ba in FIG. 8 is a control of the robot hand 3 in the robot control panel 15a. The control flow for is shown.

  The control flow Ba of the robot hand 3 in the robot control panel 15a includes step B16 in place of step B1 in the same processing procedure as the control flow B shown in FIG. In the step B16, the processing similar to that shown in step A1 of FIG. 3 performed by the welding machine control device 16 in the apparatus configuration shown in FIG. The welding conditions, the conditions for the circumferential operation of the welding torch 10 according to the welding conditions, the number of each dividing point Pm, and the setting for the position where the welding torch 10 should be arranged when welding each dividing point Pm are shown in FIG. 3 is performed together with the setting of the circular motion of the entire branch pipe welder 4 by the robot hand 3 corresponding to the circumferential motion of the welding torch 10 based on the same welding conditions as in step B1 shown in FIG.

  Further, when the robot control panel 15a starts the welding operation by starting the circular motion of the entire branch pipe welder 4 by the robot hand 3 in step B7 of the control flow Ba, the robot controller 15a performs the step by the welder control unit 17. As C1, the start processing of the welding operation of the branch pipe welder 4 similar to step A3 in the control flow A shown in FIG. 3 is performed. Thereby, in the said branch pipe welding machine 4, after the welding torch 10 starts welding about the welding location of the branch pipe 2 and the mother pipe 1, the circumferential operation | movement of the clockwise direction of this welding torch 10 is started. Become so.

  Therefore, in the automatic welding apparatus I, the first layer (one pass) welding operation is started at the welded portion between the branch pipe 2 and the main pipe 1 (step B8).

  Thereafter, after the robot control panel 15a starts welding work as described above, the circumferential welding operation of the branch pipe 2 by the circumferential operation of the welding torch 10 is performed in the circumferential direction of the branch pipe 2. When the process proceeds to the set first division point Pm (m = 1) (step B9), the process proceeds to step B10, and is calculated corresponding to the division point Pm (m = 1) in step B16. The positioning operation is performed with the robot hand 3 as a target at the position where the entire branch pipe welder 4 is to be placed. At this time, at the same time, in the welder control unit 17, the branch pipe welder set in step B16 corresponding to the division point Pm (m = 1) as step C2 as in step A5 of FIG. In step 4, the positioning operation is performed with the position where the welding torch 10 is to be disposed as a target.

  After performing the positioning operation in Step B10 and Step C2, the robot control panel 15a performs the circumferential operation of the welding torch 10 by the branch pipe welder 4 and the circular operation of the entire branch pipe welder 4 by the robot hand 3. And the welding operation up to the next division point Pm (m = 2) (see FIG. 5) in the order set in the circumferential direction of the branch pipe 2 is resumed.

  Thereafter, the robot control panel 15a and the welder control unit 17 determine that the welding operation in the circumferential direction of the branch pipe 2 by the welding torch 10 is sequentially set in the circumferential direction of the branch pipe 2. = 2, 3, 4,...) (Step B11), the welding torch 10 is arranged by the branch pipe welder 4 corresponding to the dividing point Pm, similarly to the above steps C2 and B10. After performing the positioning operation targeting the position to be placed and the position at which the entire branch pipe welder 4 is to be arranged by the robot hand 3 (step C3, step B12), welding toward the next division point Pm is performed. The process of resuming work is repeated.

  Thus, at each of the dividing points Pm (m = 1, 2, 3,...), The circumferential operation of the welding torch 10 by the branch pipe welder 4 and the branch pipe welding by the robot hand 3 (see FIG. 1). Since the difference in operation start timing from the circular motion of the entire machine 4 and the synchronization shift due to the difference in operation speed are eliminated, every time the welding operation reaches each division point Pm, the shift of the welding target position is Each will be resolved.

  The robot control panel 15a reaches the welding end point that coincides with the welding start point after the circumferential welding operation of the branch pipe 2 has passed through all the dividing points Pm, and the entire circumference of the branch pipe 2 in the circumferential direction. When the welding work over is finished, the first layer welding is finished (step B13).

  Thereafter, the robot control panel 15a and the welding machine control unit 17 perform the N-th layer welding operation by the same processing as in the above-described Steps B7 to B13 and Steps C1 to C3 as necessary (Step B14). ) When the welding operation for all the set layers is completed (step B15), the welding operation is terminated.

  Thus, according to the welding aim displacement prevention method of the automatic welding apparatus of the present embodiment, since the welding machine control unit 17 is incorporated in the robot control panel 15a, the welding torch 10 in the branch pipe welding machine 4 is provided. It is possible to reduce a possibility that a difference occurs between the circumferential operation and the operation start timing of the circular operation of the entire branch pipe welder 4 by the robot hand 3. Further, the synchronization shift caused by the difference in operation timing and the difference in operation speed of each operation can be eliminated for each division point Pm in the middle of the welding operation. Therefore, the shift of the welding target position can be eliminated at each division point Pm.

  Therefore, the present embodiment can provide the same effects as those of the embodiment of FIGS.

  In addition, this invention is not limited only to the said embodiment, You may set arbitrarily the number of the division | segmentation points Pm set to the circumferential direction of the branch pipe 2 if it is one or more. Thus, branch pipe welding set in advance corresponding to the dividing point Pm during the welding operation over the entire circumference in the circumferential direction of the branch pipe 2 by the circumferential operation of the welding torch 10 of the branch pipe welder 4 is performed. The positioning operation targeting the position at which the welding torch 10 should be arranged by the machine 4 and the position at which the entire branch pipe welding machine 4 should be arranged by the robot hand 3 can be performed one or more times. For this reason, since the welding operation is resumed after the deviation of the welding target position is once resolved at the time of the above positioning operation, the welding target is required in the welding operation over the entire circumference of the branch pipe 2 in the circumferential direction. Even if the position shift temporarily occurs, it is possible to prevent the shift of the welding target position from affecting the entire welding operation over the entire circumference in the circumferential direction or the accumulation of the shift of the welding target position.

  It should be noted that it is desirable to set many division points Pm. This is the welding target position that occurs from the start of the welding operation in the circumferential direction of the branch pipe 2 until the order reaches the first division point and from the certain division point Pm to the next division point Pm. The time required for the positioning operation of the welding torch 10 by the branch pipe welder 4 and the positioning operation of the entire branch pipe welder by the robot hand 3 performed at each dividing point Pm can be shortened. be able to.

  At the tip of the robot hand 3, the branch pipe before the horseshoe-type guide 5 of the branch pipe welder 4 is externally fitted to the branch pipe 2 to be welded, as shown in Patent Document 1. It is good also as a structure which attaches the probe for detecting the position of 2 previously by touch sensing.

  After the horseshoe-shaped guide 5 of the branch pipe welder 4 is externally fitted to the branch pipe 2 to be welded, the above-described branch pipe 2 to be welded and the lower part thereof are touched by the touch sensing using the wire 11 of the welding torch 10. Regarding the welding location with the mother pipe 1, it has been shown as obtaining position information over the entire circumference in the circumferential direction, but if it is possible to obtain position information over the entire circumference in the circumferential direction of the welding location, Instead of the touch sensing, sensing with a heat-resistant optical or magnetic displacement sensor may be performed so that the signal is input to the robot control panels 15 and 15a.

  The direction in which the welding torch 10 is operated circumferentially when welding the welded portion between the branch pipe 2 and the mother pipe 1 over the entire circumference of the branch pipe 2 may be any direction. When performing multi-layer welding, the direction in which the welding torch 10 is operated circumferentially may be reversed between the odd-numbered layer welding operation and the even-numbered layer welding operation.

  Of course, various modifications can be made without departing from the scope of the present invention.

I Automatic Welding Equipment 1 Mother Pipe 2 Branch Pipe 3 Robot Hand 4 Branch Pipe Welder 5 Horseshoe Guide (Guide)
5a Notch 10 Welding torch Pm Dividing point

Claims (1)

A guide having a notch for externally fitting to a branch pipe at a distal end portion of a robot hand of the robot, and a welding torch held by the guide and capable of moving circumferentially beyond the notch An automatic welding apparatus equipped with a branch pipe welder is used to arrange the circumferential movement of the welding torch by the branch pipe welder and to push the tip of the welding torch into the welded portion between the branch pipe and the mother pipe. When performing the welding operation over the entire circumference in the circumferential direction of the branch pipe at the welding portion of the branch pipe and the mother pipe by performing the circular motion of the entire branch pipe welder by the robot hand,
In the circumferential direction of the branch pipe, a division point obtained by dividing a plurality of welding locations over the entire circumference in the circumferential direction is set in advance, and a position where the welding torch is to be arranged by the branch pipe welding machine corresponding to the division point; Preset the position where the entire branch pipe welder should be placed with the robot hand,
When the welding operation reaches the dividing point, a positioning operation is performed with the position where the welding torch should be arranged by the branch pipe welding machine corresponding to the dividing point and the position where the entire branch pipe welding machine should be arranged by the robot hand. Done
A welding target misregistration suppression method for an automatic welding apparatus, wherein after the positioning operation of the welding torch and the entire branch pipe welder is completed, the subsequent welding operation is resumed.

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