JPH0441078A - Method and equipment for automatic welding - Google Patents

Abstract

PURPOSE:To improve a shape and dimensions of build-up welding by moving a welding torch in the adjustable plural directions and rotating the welding torch so as to always oscillate in the surface to cross orthogonally a weld line. CONSTITUTION:The moving amounts D and E in the direction to cross orthogonally the center line of oscillation of the welding torch 2 and in the axial direction are converted into the moving amounts H and V in the adjustable two directions of the welding torch 2. The welding torch 2 is moved, respectively in the two directions by the moving amounts H and V. The welding torch 2 is rotated so as to always oscillate in the surface to cross orthogonally the weld line. The welding torch 2 is oscillated and rotated by an oscillating device capable of adjusting an angle. Consequently, the occurrence of inconvenience such as a gas shielded part of the torch tip being brought into contact with a weld zone can be prevented.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to an automatic welding method and apparatus.

(b) Conventional Technology Japanese Patent Publication No. 1-20956 discloses a method for welding by automatically running a welding torch along a welding line in a welded area. The welding torch is oscillated at regular intervals in a plane perpendicular to its direction of movement (the direction driven by the longitudinal movement device), and the welding current and amount of oscillation during the oscillation are measured, and from these values Welding is performed while the swing center position is corrected by the lateral drive device according to the calculated correction direction and correction amount. As a result, the weld line AB has a bent shape as shown in FIG. 9, for example.
Even in the case of a welded object having a welding process, the welding torch is moved along the welding line as welding progresses, and continuous automatic welding can be performed.

C) Problems to be Solved by the Invention However, in the conventional method as described above, when welding a welded part having a bent shape as shown in FIG. Generally, it is set to be located within a plane perpendicular to the weld line AC connecting point A and bending point C. Therefore, the direction of swing of the welding torch in the section of the welding line CB is out of the plane perpendicular to the welding line CB. As a result, as shown in FIG. 9 when the weld bead is expanded in a plane, the bead width It will become narrower (the thickness of the overlay will also change). Note that if such welding with bending points is performed continuously, not only will the shape quality of the bead deteriorate as described above, but if this is welded by horizontal fillet welding, the section of weld line CB In this case, a problem occurs in which the gas shield portion at the tip of the welding torch comes into contact with the welding member when the welding torch swings. Therefore, if you stop the welding operation every time you reach such a bending point, change the direction of the welding equipment to match the welding line, and correct the direction of the welding torch's swing, you can achieve the above-mentioned results. Although defects can be avoided, there is a problem in that work efficiency decreases.

The present invention aims to solve the above problems.

(d) Means for Solving the Problems The present invention solves the above problems by configuring the welding torch to be rotatable about a vertical line passing through the tip of the wire of the welding torch. That is, the automatic welding method according to the present invention is intended for performing arc welding by moving the welding torch (2) along a welding line having a curved part, and the automatic welding method according to the present invention is intended for arc welding by moving the welding torch (2) along a welding line having a curved part. The welding torch (2) is oscillated at a constant period (T) about the center line of the welding torch (2) in a plane perpendicular to the preset welding line of the welding torch (2). Detecting the same frequency component (S) as the oscillation period (T) of the welding torch (2) among the frequency components of the welding current; Detecting the average welding current value (Q) during one oscillation period. ), and the same frequency component (S) as the detected oscillation period (T).
Calculate the amount of movement (D) of the welding torch (2) in the direction perpendicular to the swing center line in order to reduce the absolute value of the detected average welding current (Q) and its initial value. Calculate the amount of movement (E) of the welding torch (2) in the axial direction of the swing center line in order to reduce the difference between (D) and the amount of movement in the axial direction of the swing center line (E
) into an adjustable amount of movement in two directions (H and ■) of the welding torch (2), and moving the welding torch (2) by the amount of movement in the two directions (H and V) that has been converted. The welding torch (2) is characterized by being moved in each of the above two directions, and by rotating the welding torch (2) so that the welding torch (2) always swings in a plane perpendicular to the welding line.

Further, the automatic welding device according to the present invention includes a welding torch (2)
, a swinging device (4) that swings the welding torch (2) around an angle-adjustable swinging center line;
); a vertical movement device (14) capable of moving the swing device (4) in a vertical direction orthogonal to the welding feed direction; a horizontal movement device (16) capable of moving the swinging device (4) in a horizontal direction perpendicular to the welding feeding direction; a feeding device (18) capable of moving the swinging device (4) in the welding feeding direction; and a welding torch. Wire feeding device (6) that feeds the wire (8) to (2)
) and a welding power source (2) that supplies welding current to the wire (8).
6), a current detector (30) that detects the welding current, a swing position detector (32) that outputs a signal when the welding torch (2) is at a predetermined swing position, and a welding torch (2). an inclination angle detector (34) that detects the inclination angle (θ) of the oscillating center line with respect to the vertical direction, a feed position detector (44) that detects the welding direction feed position of the welding torch (2), and a current detection The oscillation period (T
) and a signal processing means for determining the normal and reverse phase of the frequency component (S) and the average welding current (Q); The amount of movement of the welding torch (2) in the direction of
) and the welding torch in the axial direction of the oscillating shaft (4a) based on the average welding current (Q) obtained by the signal processing means and its initial value. (2) A swing center line axial movement calculation means for calculating the movement amount (E), and converting both movement amounts (D) and (E) into a horizontal movement amount (H) and a vertical movement amount (V). a conversion means for converting; a movement command means for outputting a signal for operating a horizontal movement device and a vertical movement device according to the horizontal movement amount (H) and vertical movement amount (V) obtained by the conversion means; Feed distance (ΔL) and horizontal movement amount (
and a rotation command means for outputting a signal to rotate the rotation device (23, 24 or 25) based on the ratio of the rotation device (23, 24 or 25) to the welding device. torch(
2), with the tip (0) of the wire (8) positioned at the center of swing, move the swinging device (4) along a vertical line passing through the tip (0) of the wire (8). The relative positions are set so as to rotate around the center. Note that the symbols in parentheses indicate corresponding members in the embodiment.

(E) Operation During horizontal fillet welding, the welding torch is held in a plane orthogonal to the straight or curved welding line with its center line of oscillation inclined at a predetermined inclination angle with respect to the welding part. It is made to swing around the swing center line. In addition, in this specification, the inside of the plane orthogonal to a curved welding line shall mean the same content as the inside of the plane orthogonal to the tangent of a curved welding line. During this oscillation, among the frequency components of the welding current, a frequency component that is the same as the oscillation period of the welding torch is detected, and 1
An average welding current value during the oscillation period is detected. Based on these detected values, the amount of movement in the direction perpendicular to the welding line and the amount of movement in the direction of the welding line in order to maintain the welding torch in a predetermined positional relationship with respect to the welding part are determined, and the amount of movement in the direction of the welding line is determined. A horizontal and vertical movement is performed. By doing so, the welding torch is maintained in a predetermined positional relationship with respect to the welding part, and welding is performed. Furthermore, the rotation angle of the welding torch is determined from the welding feed distance and the amount of horizontal movement, and the welding torch is rotated by this rotation angle. As a result, the swing plane of the welding torch is always maintained at a position perpendicular to the welding line, and even curved objects can be welded with the same bead shape and size.

(F) Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 8 of the accompanying drawings.

FIG. 1 schematically shows an automatic welding apparatus according to an embodiment of the present invention.

Welding torch 2 is swingably supported by swing device 4 . The swinging device 4 is capable of swinging the welding torch 2 at a predetermined constant period about the axis of the shaft 4a. The swing device 4 is provided with a swing position detector 32 that outputs a signal when the welding torch 2 is at a predetermined swing position, and a tilt angle detector 34 that detects the tilt angle θ of the welding torch 2 with respect to a vertical line. It is being A wire 8 can be fed to the welding torch 2 from a wire feeding device 6 . The swinging device 4 is rotated about a vertical line passing through the tip 0 of the wire 8 with the tip O of the wire 8 at the swinging center position by the driving part of the rotation device 24 provided at the upper part of the swinging device 4 in FIG. It is possible to move. Details of the rotation device 24 will be explained later. In FIG. 1, a vertical movement device 14 is provided above the rotation device 24. As shown in FIG. Vertical movement amount fl! Reference numeral 14 denotes a rotating device 24. The swinging device 4 and the welding torch 2 can be moved up and down in the figure, that is, in the vertical direction. Note that the vertical movement device 1
The movement of 4 is performed by converting the rotation of the servo motor 14a connected thereto into linear motion. In Figure 1,
A horizontal movement device 16 is provided to the left of the vertical movement device 14. The horizontal movement device 16 includes a vertical movement device 149 and a rotation device 24 . The welding torch 2 can be moved in the left and right directions in the figure, that is, in the horizontal direction, via the swing device 4. Note that the horizontal movement device 16 is moved by converting the rotation of a servo motor 16a connected thereto into linear motion. The horizontal displacement device 16 is attached to the feed device 18 . The feeding device 18 is a first
Bearings 3 provided on the left and right sides of the frame 36 in the figure
8 to move in the feeding direction perpendicular to the plane of the paper. Further, a feed position detector 44 is provided to detect the feed position in the welding direction. Note that a driving device that drives the feeding device 18 in the feeding direction is not shown. Feeding device ] 8 is a horizontal movement device 16 . The welding torch 2 can be moved in the feed direction via a vertical movement device 14 or the like. As shown in FIG. 1, a welding power source 26 is provided that electrically connects the wire feeding device 6 and the workpiece W to be welded and supplies current thereto.
6 is provided with a current detector 30 for detecting the welding current. In addition, the rocking device 49 and the rotating device 24. A control device 28 that controls the servo motors 14a and 16a, the detectors 30, 32, and 34, and the welding power source 26 is provided.

A wiring 90 electrically connects the control device 28 and the servo motor 14a. Similarly, a wiring 92 is used between the control device 28 and the servo motor 16a, a wiring s94 is used between the control device 28 and the feed device 18, and a wiring 96 is used between the control device 28 and the feed position detector 44. A wiring 98 is connected between the control device 28 and the current detector 30.
The wiring 100 connects the control device 28 and the tilt angle detector 3 to the control device 28 and the tilt angle detector 3.
4 by an arrangement 102, and a wiring 104 between the control device 28 and the drive section of the rotation device 24. These wirings allow the control device 28 to connect the swing position detector 32 as shown in FIG.
The signal P when the welding torch 2 is at the swing center position and the angle θ (see FIG. 6) measured from the vertical position of the welding torch 2 at this time are input from the inclination angle detector 34, and the feed It is possible to input the feed position from the position detector 44 and to input the welding current A from the current detector 30. The control device 28 also controls the rocking device 4
Outputting a command signal to cause the welding power source 26 to oscillate at a predetermined period T, outputting a command signal to drive the feeder 18, outputting a command signal to cause the welding power source 26 to flow with a welding current, and The horizontal movement amount H is applied to the direction movement device 16.
outputting a command signal to the vertical movement device 14 to move by a vertical movement amount V, and outputting a command signal to the rotation device 24 to move by a rotation angle α
It is possible to output a command signal to rotate by a certain amount.

Next, details of the rotation device 24 will be explained using FIG. 2. An arm member 10 having two holes provided in a direction orthogonal to the axis of the swing shaft 4a is fixed to the swing device 4,
A bracket 12 is placed above this in FIG. The bracket 12 is vertically movably supported by a vertical displacement device 14 . A shaft 20 is fixed to the lower surface of the bracket 12 in FIG. 2, and the shaft 20 is fitted into one hole of the arm member 10. An extension of the axial center of the shaft 20 is arranged to pass through the tip O of the wire 8 of the welding torch 2 when the tip O is at the swing center position. A hydraulic cylinder device 22 is attached to the bracket 12, and a shaft 22a is attached to the end of the rod thereof. The shaft 22a is fitted into the other hole of the arm member 10, so that the swinging device 4 is connected to the hydraulic cylinder device 22. By moving the rod of the fluid pressure cylinder device 22, the swing device 4 can be rotated about the shaft 20 via the arm member 10. Fluid pressure cylinder device 22. Arm member 10. A rotation device 24 is configured by the shaft 20 and the like. The welding torch 2 can be rotated in a horizontal plane by a rotation device 24 while being integrated with a rotation device 4 . As a result, even when the welding line is bent as shown in FIG. 5, the rotating device 24 rotates by the rotational angle α, so that the oscillating plane of the welding torch 2 is always perpendicular to the welding line. It is possible to maintain the object so that it is in the same plane. The operating principle will be explained below. Now, in FIG. 5, it is assumed that the lower zero point is the welding start position, and welding starts upward. Initial feed position at point 0. and the initial angle φ between the welding line and the feed direction. Set each to ○. When the feed is started, the feed position 1 of one point is read from the feed position detector 44, and the feed distance ΔL from point 0 to point 1 is determined. Next, the angle φ1 between the welding line and the feeding direction is determined from the moving amount H3 of the horizontal movement device 16 and the feeding distance ΔL1.

ΔL, =L, -L.

φ+ = tan-' (H+ ÷△L,) Angle φ1 between the welding line and the feeding direction and the previous angle φ.

Find the rotation angle α1 from .

al:φ1-φO:0 Angle φ1 and φ. Since both are 0, the rotation angle a is also O, and there is no need to rotate it at point 1. Similarly, at point 2, ψ2=0 and α2=O, and no rotation is required here. Next, at point 3, a8 = φ 3 - φ 2 : φ 3, and the rotation device 24 is rotated by φ. Furthermore, at point 4, a4:φ4−φ3:0 is established, and rotation at this point becomes unnecessary.

By repeating the above operations, the welding torch 2 can always be oscillated in a plane orthogonal to the welding line.

Next, the operation of this embodiment will be explained using the signal system diagram in FIG. 7 and the flowchart in FIG. 8. First, the inclination angle θ(
(see FIG. 6) is read and stored in the control device 28. Further, the initial angle φ between the initial feed position aLo of the feed device 18 and the feed direction of the welding line. The value of is set to O (step 50). Swinging of the swinging device 4, feeding of the feeding device 18, and energization of the welding power source 26 are started (step 52). It is checked whether the tip of the welding torch 2 is located at the swing center position, and if not, wait until the tip of the welding torch 2 is located at the swing center position (step 5).
4). It is checked whether welding is completed at the swing center position (step 56). If the welding is not completed, the current detector 34 detects the welding current A at this time.

(i = 1.2.3...M) is read and stored in the control device 28 (step 58). It is checked whether the preset time has elapsed (step 6).
0), the welding torch 2 is oscillated every time a predetermined time elapses.
It is checked whether the has returned to the swing center position (
Step 62]. M during one cycle from step 58 to step 62 until the welding torch 2 returns to the swing center position.
repeated times. When the welding torch 2 returns to the swing center position, welding current A, a frequency component S of (i = 1.2.3...M) that matches the swing period T of the welding torch 2, and the positive and negative phases of this. and the average welding current Q are determined (step 64). Next, welding current A, (i=1.2.3...
・M) Find the amount of movement of the welding torch 2 in the direction perpendicular to the oscillation center line according to the frequency component S that matches the oscillation period T of the welding torch 2, and calculate the average welding current Q and its initial value. The amount of movement E of the welding torch 2 in the axial direction of the swing center line is calculated from (step 66). Convert both movement amounts and E into horizontal movement amount H and vertical movement amount V (step 6
8). A command signal for driving the horizontal movement device 16 and the vertical movement device 14 is output in accordance with the converted movement amounts H and (2) (step 70).

Feed position from the feed position detector 44, (j=1.2
3...) is read and stored in the control device flt28.

Also, calculate the moving distance ΔLJ (j=1.2.3...) for one swing cycle from the difference from the previously stored feed position (
Step 72). From the moving distance ΔL of the feeding device 18 and the horizontal moving distance HJ (j=1.2.3...), find the angle φ, (j=1.2.3-) between the welding line and the feeding direction. The information is stored in the control device 28 (step 74).

Also, calculate the rotation angle α, (j=1.2.3...) from the difference between the previously memorized welding line and the angle of the feed direction,
A command signal is output to rotate the rotation device 24 by the rotation angle α (step 76). until the welding is finished.
Step S6 to step 76 are repeated. If the welding is finished, the power to the welding power source 26 is stopped, welding is stopped, the feeding device 18 stops moving, and the swinging of the swinging device 4 is stopped (step 80). By doing so, the swinging plane of the welding torch 2 can always be maintained in a plane perpendicular to the welding line. For example, in the case of welding having a lightning-shaped bend, the movement amount difference ΔH is usually O until the first bend is reached, so steps 72 to 76 do not actually function. When a horizontal movement is performed during welding after reaching the bending part, the above steps function and the welding torch 2 is rotated in a predetermined manner.

Note that instead of the rotation device 24, a configuration as shown in FIG. 3 may be used. That is, the bracket 12 is provided with a crescent-shaped through groove 40, and the swinging device 4
A hole 4b is provided in a direction perpendicular to the axis 4a.

The center point of the arc of the through groove 40 is set so that a vertical line passing through it passes through the tip O when the wire 8 is at the swing center position. The shaft 27 provided at the tip of the rod of the fluid pressure cylinder device 22 passes through the through groove 40 and is fitted into the hole 4b of the swing device 4. A guide plate 42 is attached to the shaft 27 and slides with the bracket 12 to guide the movement of the rod of the hydraulic cylinder device 22. By moving the rod of the fluid pressure cylinder device 22, the swing device 4 can be rotated in an arc shape along the through groove 4o. Bracket 1
29 through groove 40. Fluid pressure cylinder device 22, shaft 27.
The rotation device 25 is constituted by the guide plate 42 and the like.

The function of this embodiment is such that the shaft 27 has a crescent-shaped through groove 40.
Except that the rotating device 25 rotates about a vertical line passing through the tip O of the wire 8 by being guided by the wire 8.
This is similar to what was explained earlier.

FIG. 4 shows another embodiment of the rotating device. The swinging device 4 is connected to a servo motor 23a by an arm member 23b. The arm member 23b is connected to the rotating shaft of the servo motor 23a at a predetermined angle, thereby making it possible to move the swinging device 4 along the circle C. A rotation device 23 is configured by the servo motor 23a and the arm member 23a. The operation of this embodiment is similar to that described above, except that there is no limit to the rotation angle of the rocking device 4.

Note that it is obvious that the automatic welding method of the present invention enables welding of only straight portions, circumferential welding, and the like.

(G) As described in detail, according to the present invention, even in a welded part where the weld line is curved or lightning-shaped, the oscillating plane of the welding torch is always perpendicular to the weld line. Since it can be maintained within the plane, the shape and dimensions of the build-up for welding can be made favorable. Further, even if welding in the above-described shape is performed by horizontal fillet welding, problems such as the gas shield portion at the tip of the torch coming into contact with the welded portion will not occur.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a basic automatic welding device according to the present invention;
FIG. 2 is a diagram showing an embodiment of the rotating device used in the automatic welding device of the present invention, FIG. 3 is a diagram showing another embodiment of the rotating device, and FIG. 4 is a diagram showing another embodiment of the rotating device. Schematic diagram showing an example, No. 5
6 is a diagram showing the relative position of the welding torch with respect to the workpiece, FIG. 7 is a diagram explaining the signal system of the control device, and FIG.
9 is a flowchart of the automatic welding apparatus of the present invention, and FIG. 9 is a diagram illustrating a swing locus of a welding torch on a bent workpiece by a conventional automatic welding apparatus. 2. Welding torch, 4. Rocking device, 6. Wire feeding device, 8. Wire, 14. Vertical movement device, 16. Horizontal movement device, 18. Feeding device. 23・24・25・・Rotating device, 23a・・Servo motor, 23b・・Arm member, 26・・Welding power source, 28・・Control device, 30・・・Current detector, 32・
... Rocking position detector, 32 ... Rocking position detector, 34
... Tilt angle detector, 44... Feed position detector. Patent Applicant Japan Steel Works Co., Ltd. Agent Patent Attorney Toshiyuki Miyauchi Figure Floor 1 Figure 6 Figure 7 Figure 7

Claims (1)

[Claims] 1. Welding torch (2) along a welding line having a curved part
In an automatic welding method in which arc welding is performed by moving the welding torch (2), the swing center line of the welding torch (2) is set to a desired inclined state according to the welding part, and the welding line of the welding torch (2) is set in advance. The welding torch (2) is oscillated at a constant period (T) about the oscillation center line in a plane orthogonal to the oscillation period (T) of the welding torch (2) among the frequency components of the welding current. Detecting the same frequency component (S) as the above detected oscillation period (T); Detecting the average welding current value (Q) during one oscillation period; detecting the same frequency component (S) as the detected oscillation period (T).
Calculating the amount of movement (D) of the welding torch (2) in the direction perpendicular to the swing center line in order to reduce the absolute value of Calculating the amount of movement (E) in the axial direction of the swing center line of the welding torch (2) in order to reduce the difference from the initial value of the welding torch (2); (D) and the amount of movement (E) in the axial direction of the swing center line.
) into adjustable amounts of movement (H and V) of the welding torch (2) in two directions, and moving the welding torch (2) by the converted amounts of movement (H and V) in the two directions. An automatic welding method characterized by: moving the welding torch (2) in each of the above two directions; and rotating the welding torch (2) so that the welding torch (2) always swings in a plane perpendicular to the welding line. 2. A welding torch (2) and a swinging device (
4), a rotating device (23, 24 or 25) capable of rotating the swinging device (4), and a vertical device capable of moving the swinging device (4) in a vertical direction perpendicular to the welding feed direction. A directional movement device (14), a horizontal movement device (16) that can move the swing device (4) in a horizontal direction perpendicular to the welding feed direction, and a swing device (4) that can move the swing device (4) in the welding feed direction. A feeding device (18), a wire feeding device (6) that feeds the wire (8) to the welding torch (2), a welding power source (26) that feeds the welding current to the wire (8), and a welding power source (26) that feeds the welding current to the welding torch (2). a current detector (30) for detecting; a swing position detector (32) for outputting a signal when the welding torch (2) is at a predetermined swing position;
An inclination angle detector (34) that detects the inclination angle (θ) of the swing center line of the welding torch (2) with respect to the vertical direction, and a feed position detector (44) that detects the welding direction feed position of the welding torch (2). ) and the frequency component (S) and phase of the welding current that match the oscillation period (T) of the welding torch (2) based on the signals from the current detector (30) and the oscillation position detector (32). A signal processing means for determining the forward and reverse welding current (Q) and the above frequency component (Q) obtained by the signal processing means.
A movement amount calculating means in a direction perpendicular to the swing center line that calculates a movement amount (D) of the welding torch (2) in a direction perpendicular to the swing center line according to S), and the above-mentioned average obtained by the signal processing means. From the welding current (Q) and its initial value, the swing axis (4a
) for calculating the amount of movement (E) of the welding torch (2) in the axial direction of the welding torch (2);
A conversion means for converting D) and (E) into a horizontal movement amount (H) and a vertical movement amount (V), and a horizontal movement amount (H) and a vertical movement amount (V) obtained by the conversion means.
a movement command means that outputs a signal to operate the horizontal movement device and the vertical movement device according to the amount of movement, and a rotation device (23, 2
4 or 25), and a rotation command means for outputting a signal to rotate the welding torch (23, 24 or 25).
2), with the tip (0) of the wire (8) positioned at the center of swing, move the swinging device (4) along a vertical line passing through the tip (0) of the wire (8). An automatic welding device characterized in that relative positions are set so as to rotate around a center.