JPS6036345B2 - Narrow gap welding method and equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a narrow gap welding method and apparatus, and more particularly to a method and apparatus for swinging a wire tip from side to side within a narrow gap.

When butt welding thick plates, do not create a V-shaped or rhombus-shaped groove, but simply make a single-shaped groove by making the side greens of both thick plates face each other with a narrow gap inside and outside one rib. Both thick plates are welded together by filling the tip with molten metal, that is, narrow gap welding is often performed. Several types of devices have already been proposed for automatically welding such narrow gaps. Figure 1 shows this by the trajectory of the wire tip, where a is a constant circular arc reciprocating motion of the wire tip in the direction of the groove width W, and a linear motion of the torch in the direction of the groove length L. This is the trajectory obtained, and the arc generation point moves within the groove along this trajectory,
Welding is being carried out. b is a trajectory obtained by making the wire tip move in a continuous circular motion and adding the linear motion of the torch to it, and c is a trajectory obtained by making the wire tip make a simple harmonic motion and adding the torch linear motion to it. d is a locus according to the present invention, which will be described later. However, there is a drawback that the locus of b is not symmetrical. The locus of this point a is symmetrical, and the swing can be easily stopped on both sides of the groove, but the mechanism is somewhat complicated. That is, the trajectory a is generated by the mechanism shown in FIG.
, a motor 20 or the like is required to swing it in the direction of the arrow. Note that 22 and 24 are shield gas nozzles, 26 and 2
8 is the base material, and 30 is the deposit. The welding wire 32 is strongly bent with a small radius of curvature in the bending mechanism 16 to give it plastic deformation into a curved shape, and then the large rotary disk 18a attached to the support plate 18c and the large number of small disks arranged around it When the wire is passed through the nozzle 14 after forming a loop between it and the rotating disk, the wire end 32a protruding from the tip of the nozzle is curved as shown in the figure, and the swing motor 20' reciprocates the support plate 18c in the direction of the arrow. When the wire end 32a is rotated, the wire end 32a also rotates in the same direction, and when the entire wire is moved forward, it traces a trajectory as shown in FIG. 1a. In this device, the wire is pushed out and moved forward after the wire feed mechanism 12 (bush method), so it is difficult to maintain the wire in that state by simply winding the wire around the large rotating disk 18a, and it is difficult to maintain the wire loop state. The mechanism is complicated, such as requiring a large number of rotating disks 18b. Furthermore, if the rotational movement of the wire is temporarily stopped for some reason such as adhesion of molten metal scattered during welding, the trajectory of the wire tip becomes, for example, as shown by the dotted lines P and -P2 in Fig. 1a, and extends to the base metal. Otherwise, there is a risk of poor integration of the home village side. FIG. 2b shows a mechanism that generates the locus shown in FIG. Become.

The wire 32 taken out from the reel is passed through correction rollers 40, 42.
After passing it through the mechanism 44 to remove the bending kinks,
In this step, the rollers 44a to 44c arranged in a zigzag manner are used to bend the wire into the shape shown in the figure to apply plastic deformation, and the support plate 44d of these rollers is rotated as shown by the arrow, and then the wire is passed through the wire feeding mechanism 12 from the tip of the nozzle 14. When the wire is protruded, the wire has a spiral shape, and as the tip is worn away by arcing and as the whole is subjected to linear movement, the tip 32a traces a trajectory as shown in FIG. 1b. become. Although this mechanism is relatively simple, the wire oscillation and the total length of the drive part are large, and as mentioned above, the wire tip trajectory is asymmetrical to the left and right, so the welding of the pair of base metal surfaces on both sides of the joint is poor. There is a problem that . FIG. 2c shows a mechanism for generating the trajectory of FIG. 1c. This device uses two wire feeding mechanisms 12a and 12b and uses a bush pull method. Then, just before the pull mechanism 12b, the wire 32 is moved to the left by the arm 20a of the wire swing mechanism.
vibrate to the right. This device has a simple structure and a simple weaving shape, and cannot obtain a weaving trajectory that repeatedly moves forward and backward as shown in FIG. 1a, which is widely adopted as a weaving trajectory. In addition, if an obstacle occurs that temporarily blocks the movement of the wire, please refer to Figure 1a.
The result is the same as that of The mechanism of the present invention is relatively simple, and a weaving pattern that repeats forward and backward movements can be obtained.
The present invention also aims to provide a wire swinging method and its mechanism that allows the weaving pattern to continue as planned even if an obstacle that temporarily impedes the weaving movement of the wire occurs and causes less problems such as poor welding. . Next, the present invention will be explained first with respect to the weaving locus of the wire tip and then with respect to the weaving mechanism. FIG. 1d shows the weaving locus of the present invention.

As shown in this figure, the main weaving locus is a combination of a reciprocating rotation movement greater than 180 degrees and less than 360 degrees, and a linear motion. According to this trajectory, the base metal surfaces F, , F2 on both sides of the joint (more specifically, the immediate vicinity thereof) are scanned reciprocally by the firing point of the wire tip, and penetration into the base metal surface is ensured. Further, even if the rocking motion is temporarily stopped due to an obstacle, the planned trajectory is maintained and poor penetration is avoided, even if the trajectory only jumps from point P to P2. Of course,
The wire tip does not move to part P3, but the wire tip passes through point P4 in the vicinity on the return stroke, and moves from P3 to P4.
Ensure that the part penetrates into the base material. In other words, this weaving trajectory has sufficient overlapping parts, so it has strong resilience against temporary failures. In addition, if there is an overlapping part, the wire may have curls during manufacturing or from being wound on a reel, and the curved shape of the wire end protruding from the tip of the torch may not be the planned weaving trajectory. ), it has the advantage of being retained. In addition, near the base metal surface, the wire tip moves back and forth from P, P3, P2, P5, P4, P6 and takes a relatively long time, so during this time, there is no risk of the wire getting caught. It is expected that temporary failures will disappear, and reliable welding can be expected from this aspect as well. FIG. 3 shows the main part of the mechanism that generates the locus shown in FIG. 1d, that is, the wire plastic deformation imparting and rocking device. Although not shown, a wire feeding mechanism, a wire straightening mechanism, a conduit cable, and a wire reel are provided on the wire 32 entry side of this device 50. The portion of the torch 14 on the wire outlet side is similar to that shown in FIG. 2a, and is provided with a shield gas nozzle 22 and the like. The torch 14 and the nozzle 22 have a rectangular annular cross section in which the vertical sides (sides in the width direction of the groove) are considerably shorter than the horizontal sides so as to fit within the narrow joint. 52 is a housing of the device 50, and three pairs of roller groups 54 are installed in this coating body.
A support plate 54 and the like that support a, 54b, and 54c are provided.

Among these roller groups, roller pairs 54a and 54 at both ends
The rollers 54c are fixedly and rotatably attached to the support plate 54, while the center roller pair 54b is rotatably and laterally movable along the outermost hole 54d. This lateral movement is performed by the knob 56 and bends the wire 32 held between the pair of rollers into a dogleg shape. Hollow tubes (wire nozzles) 58 and 60 are fixed to both ends of the support plate 54, and these hollow tubes are rotatably supported by the housing 52 by bearings 62 and 64. A gear 97 is located in the middle of the hollow tube 58.
is fixed, and a wire guide 66 is attached to the lower end of the hollow tube 60. The wire guide 66 passes through the center of the torch 14, and the upper end of the torch 14 is screwed into a bearing bush 68, and a ground terminal plate 70 is attached to the brackets with nuts 72 and 74. A swing motor 76 is attached to one side wall of the outer shell 50, a flange 78 is fixed to its output shaft, and a roller 80 is attached around the periphery of the flange by a shaft 82.

Reference numeral 84 denotes a slider which is engaged with a pair of shafts 86 and 88 supported at both ends by the outer basket 52, and has an elongated hole inside thereof extending in the vertical direction in the drawing, into which the roller 80 is engaged. Therefore, when the motor 76 rotates, it generates simple vibration in the directions 86 and 88 (front-back direction in the drawing).

A rack 90 is attached to this slider 84, and this rack meshes with a small diameter gear portion of a two-stage gear 92. The gear 92
The large prong gear meshes with the gear 97 of the hollow tube 58. 94 is a support shaft of the gear 92, and 96 is a bearing bush.

The welding wire 32 passes through the device 50 along the path of the bearing bush, the hollow tube 58, the roller pairs 54a to 54c, and the hollow tube 60. In this device, when the motor 76 rotates, the slider 84 causes simple vibration, the gears 92 and 97 rotate via the rack 90, and the support plate 54 reciprocates around the hollow shafts 58 and 60.

This rotation range is determined by the simple harmonic amplitude of the slider 84, which is determined by the amount of positional deviation of the roller 80 from the motor output shaft, and the gear ratio of the gears 90, 92, and 97. Set it to a range smaller than 3600, for example 3200. If the position of the shaft 82 on the flange 78 is made adjustable by, for example, attaching the shaft 82 to a piece (not shown) and moving the nut-shaped piece with a feed screw, the rotation range of the support plate 54 can be adjusted. It can be adjusted at any time. This reciprocating rotation of the support plate 54 is caused by the roller pairs 54a to 54a.
At step 54c, the wire 32 bent in the shape of 〈 is rotated around a line connecting both ends of the wire.Therefore, the wire is rotated around the center line of its straight portion, and the wire is The wire is bent in the shape of an o-ra and has a bending groove, and when it protrudes from the tip of the torch, it is curved, so the tip of the wire that protrudes from the tip of the torch forms an arc, and this When the forward motion of a torch or the like is added to the curve, the trajectory shown in Fig. 1d will be drawn. The range Q' of the reciprocating arcuate motion of the wire tip is equal to the range of the reciprocating arcuate motion of the support plate 54, which is 3200 in the above example. The weaving trajectory shown in Fig. 1 d is symmetrical with respect to the groove center line i, but in some cases, the range of reciprocating rotation may be shifted clockwise or counterclockwise as shown in Q' to make it symmetrical. However, in this case, the mounting portion of the motor 76 to the outer weight 52 may be set to the furthest groove, and the mounting position may be shifted in the front-rear direction in FIG. 3. This wire tip weaving mechanism has advantages such as a simple structure and a short overall length. Although the above-mentioned apparatus of the present invention is an example for narrow gap welding, it is not limited thereto, and has sufficient effects for other types of welding. It can also be applied to welding where the rotation range of the reciprocating circular arc movement of the wire tip is smaller than 180 degrees. As explained above, according to the present invention, it is possible to provide a weaving pattern and its generation mechanism that are particularly suitable for narrow joint welding, which are less likely to cause poor penetration, have a simple mechanism, and can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a weaving locus, FIGS. 2 a to c are explanatory diagrams of a conventional weaving mechanism, and FIG. 3 is a sectional view of a main part of the weaving mechanism of the present invention. In the drawing, 54 is a support plate, 32 is a wire, 54a to 54b are three pairs of rolls, 12 is a wire supply mechanism, 14 is a torch,
76, 80, 82, 84, 90, 92, 62, 58, 6
0 is a swing mechanism. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A wire is bent so that the end of the wire protruding from the tip of the torch is curved, and the wire is bent at an angle larger than 180° and smaller than 360° with respect to the central axis of the straight portion of the wire. While rotating back and forth within the angular range,
A narrow gap welding method characterized by advancing a torch along the narrow gap to perform gas shield arc welding on the narrow gap. 2. A rotatable support plate, a bending mechanism that is attached to the support plate and has at least three pairs of rolls that hold the wire and bend the wire into a dogleg shape, and supplying the wire to the mechanism. A torch which is supplied with a wire with a bending kink from a bending mechanism and a kink adding mechanism and makes the wire end protrude from its tip, and a torch which transmits the rotation of a swing motor via a rack and pinion to bend the support plate by more than 180 degrees. 360°
A narrow gap welding device comprising: a swinging mechanism that rotates the wire reciprocally in a smaller angular range and rotates the wire reciprocally about the central axis of the straight portion thereof.