JP4371741B2 - Welding head with multiple torches and welding method - Google Patents

Description

  The present invention relates to a welding head in which a plurality of welding torches are arranged side by side with the torch tips close to each other, and a welding method performed by mounting the welding head on a welding robot.

  In order to improve the welding quality by controlling the voltage value and the wire feed speed given to multiple welding torches, the welding head mainly focuses on improving the productivity of welding work by increasing the moving speed of the welding head. A technique for carrying out welding by mounting a plurality of welding torches on the surface is known.

In this type of prior art, the torch tips are brought close to each other so that one pool (melt pool) is formed at the tips of a plurality of welding torches, and the welding head is placed on the workpiece while maintaining the close positional relationship. Welding is performed by moving along the welding line. Accordingly, in general, a plurality of welding torches are mounted with their mutual positional relationship fixed, but those that allow the positional relationship between the welding torches to be changed are disclosed in the following patent documents. .
JP-A-7-284927

  General-purpose automatic welding equipment provided in a welding factory is equipped with a positioner that converts the posture of the workpiece so as to always carry out downward welding with the workpiece mounted, and welding according to a machining program registered in advance under the control of the NC device. It comprises a welding robot that moves the tip of the torch along the welding line of the workpiece.

  In such general-purpose welding equipment, it is necessary to handle various workpieces with different base materials, plate thicknesses, groove shapes, etc., and the welded part is also a narrow intricate part or a long straight part There are various kinds. In order to perform welding in such various modes with high quality and high speed, it is difficult to perform welding with only one type of welding torch, and welding is performed while replacing the welding torch as necessary. ing.

  For example, the above-described one having a plurality of welding torches is suitable for welding a straight portion at a high speed, but it is difficult to weld a complicated portion, and depending on the type of the base material and the groove shape, In the conventional welding method using a plurality of torches, the welding quality may be deteriorated. In such a case, conventionally, the welding torch is replaced, or one torch is retracted and welding is performed with one torch. However, it is avoided to reduce productivity due to torch replacement or a decrease in welding speed. I couldn't.

  Therefore, the present invention provides a general-purpose welding head capable of efficiently performing high-quality welding without changing the torch corresponding to various welding sites of various workpieces, and so on. It is an object of the present invention to provide a welding method capable of high-quality welding of a plurality of pools with a plurality of welding torches of a simple welding head.

In this invention, the interval between a plurality of welding torches in the direction along the workpiece welding line can be changed, and further, one welding torch can advance and retreat in the axial direction of the torch, that is, in the direction of widening or narrowing the welding gap. In addition, the above-mentioned problems are solved by providing a welding head in which one of the other can be weaved.
That is, the composite welding head according to the first aspect of the present invention that solves the above-described problem is a composite welding head that includes a plurality of welding torches 1a and 1b arranged side by side, and expands and contracts the interval between the plurality of welding torches. An expansion / contraction device 8; and a reciprocating device 4 for reciprocating in a weaving direction orthogonal to the expanding / reducing direction, and a reciprocating device 4 for moving one of the plurality of welding torches relative to the other in the axial direction of the torch. A welding torch 1b mounted via a device 9 and a welding torch 1a mounted without such a reciprocating device, the reciprocating device being controlled by an NC device that controls the welding robot. It is a feature .

According to a second aspect of the present invention, there is provided a composite welding head comprising the above means, wherein the expansion / contraction device 8 includes a plurality of welding torches adjacent to each other to form a pool, and a plurality of welding torches. Each of the torch intervals can be changed to a wide interval forming one pool .

The welding method according to the invention of claim 3 in which the above-described problems, a welding head of the claims 1 or 2, wherein mounted on the welding robot which is controlled by the N C device, the plurality of welding torch front-rear direction A welding method in which the welding head is moved along the welding line of the workpiece in the direction of together is, before and after the welding torch tip welding torch 1b mounted through the reciprocating device 9 with an amplitude corresponding to the deviation δ of GMA width in synchronism with Uibingu operation of the robot in the section the reciprocating caused by the evacuation It is a welding method using a plurality of torches characterized by reciprocating with an apparatus.

Even in the case where welding is performed while forming one pool by bringing the ends of a plurality of welding torches close to each other, the torch interval for obtaining the optimum welding quality may be slightly different depending on the type of the base material and the groove shape. It was found by the test of the present inventors. According to the welding head of the present invention, in such a case, it is possible to perform the welding with higher quality by setting the interval in the direction along the welding line of the plurality of welding torches to the optimum interval.

  Further, according to the welding head of the present invention, the interval between the plurality of welding torches is increased so that each welding torch forms one pool, that is, a plurality of pools, and a plurality of welding torches are moved by one movement of the welding head. It is also possible to perform a welding operation in which overlaying is performed. That is, according to the conventional method, since a plurality of layers can be welded in one pass at a place where welding has to be performed in a plurality of passes (movement of the welding head) of one welding torch, the welding speed can be improved. .

When such welding is performed, the welding torch on the rear side in the traveling direction of the welding head is retracted in the torch axial direction by the amount of the build-up by the front welding torch, and the groove width of the welding front end accompanying the retraction in response to the increase, such that the amplitude of the weaving of the welding torch of the rear is wider than the amplitude of weaving of the front of the welding torch, reducing the amplitude of the weaving operation of the robot to the welding torch before or after or increased to displacement By performing the additional weaving operation in the direction to be performed, it is possible to perform the optimum welding operation in any of the plurality of torches separated from each other.

  Then, welding with only one torch with one welding torch retracted in the axial direction of the torch, welding with a plurality of pools with a plurality of welding torch tips close to each other, and a plurality of pools with a plurality of welding torch tips spaced apart Can be continuously performed while being appropriately converted during workpiece welding by the control of the NC device, so that it is possible to perform high-quality welding on a wide variety of workpieces at high speed. .

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are views showing an embodiment of the present invention. FIG. 1 is a side view, FIG. 2 is a front view (viewed from the welding torch side), and FIG. 3 is a plan view. In the figure, 1a and 1b are welding torches, and 2 is a wrist flange (attachment portion to which the welding head is attached) at the arm tip of the welding robot. As shown in FIG. 2, the two welding torches 1a and 1b are mounted side by side in parallel, with their tips 3a and 3b close to each other. The moving direction of the welding torches 1a and 1b by the welding robot is the left-right direction in FIG. The welding torches 1a and 1b are mounted with their necks sandwiched between the torch clampers 5 mounted on the rod ends of the telescopic cylinders 4a and 4b provided in parallel behind each of the welding torches 1a and 1b.

  One of the two telescopic cylinders 4 a is fixed to a first bracket 7 attached to the wrist flange 2 via a shock sensor 6. The other telescopic cylinder 4 b is attached to the first bracket 7 via an expansion / contraction cylinder 8 and a reciprocating cylinder 9. The expansion / contraction cylinders 4a and 4b, the expansion / contraction cylinder 8 and the reciprocating cylinder 9 are arranged in directions orthogonal to the other two as clearly shown in FIG. The expansion / contraction direction of the rod is the axial direction of the welding torches 1a and 1b (the vertical direction in FIGS. 1 and 2), the expansion / contraction direction of the rod of the expansion / contraction cylinder 8 is the movement direction of the welding torch (the horizontal direction in FIG. 2), and the reciprocating cylinder. 9 is a direction (left-right direction in FIG. 1) perpendicular to the moving direction of the torch.

  The mounting structure of the two welding torches 1a and 1b will be described in more detail with reference to the drawings. A first bracket 7 fixed to the wrist flange 2 via a shock sensor 6 is a sheet metal bracket bent so as to surround the expansion / contraction cylinder 8, and the expansion cylinder 4a is attached to the bent end on the front side (torch side). The body portion is fixed, and the neck portion of the welding torch 1a is fixed by the torch clamper 5 fixed to the rod tip of the cylinder. The expansion / contraction cylinder 8 is fixed to the first bracket 7 at the rod side flange portion, and the second bracket 10 is fixed to the tip of the rod. The reciprocating cylinder 9 is a rodless cylinder, and its fixed barrel portion is fixed to the second bracket 10, and the trunk portion of the telescopic cylinder 4b is fixed to the reciprocating piece 9a. The welding torch 1b is sandwiched and fixed by a torch clamper 5 fixed to the rod tip of the telescopic cylinder 4b.

  The expansion cylinders 4a and 4b, the expansion / contraction cylinder 8 and the reciprocating cylinder 9 are all servo cylinders controlled by an NC apparatus that controls the welding robot. The shock sensor 6 is used to absorb the impact and detect the impact and stop the robot when an impact due to, for example, a collision with a workpiece is applied to the welding torches 1a and 1b.

  As understood from the mounting structure, the welding torch 1a can be moved forward and backward in the axial direction by the expansion and contraction of the expansion cylinder 4a. Further, the welding torch 1b can be moved forward and backward by expansion and contraction of the expansion / contraction cylinder 4b, the distance from the other welding torch 1a can be changed by expansion / contraction of the expansion / contraction cylinder 8, and the expansion / contraction of the reciprocating cylinder 9 allows welding. It can reciprocate in a direction perpendicular to the direction of movement of the torch.

  In the welding head having the above structure, welding with a single torch is possible in a state in which any of the welding torches 1a and 1b is retracted. In addition, it is possible to perform welding in which one pool is formed with two torches in a state where both are extended or retracted, the expansion / contraction cylinder 8 is retracted, and the reciprocating cylinder 9 is stopped. Thus, the entry / exit of the tip of the torch and the interval can be adjusted as necessary by the minute operations of the expansion / contraction cylinders 4a and 4b and the expansion / contraction cylinder 8.

  When performing two pool welding in which two torches 1a and 1b each form one pool, the expansion / contraction cylinder 8 is extended to separate the torch tips 3a and 3b, and the movement of the torch as shown in FIG. The welding torch 1r (1a or 1b) on the rear side in the direction is degenerated by a height corresponding to the build-up thickness of the welding torch 1f on the front side.

  When welding along a welding line provided with a large groove, the welding robot reciprocates (weaves) the welding head in a direction perpendicular to the traveling direction of the torch, and moves the tip of the torch in a zigzag manner. When performing such welding, if the torch 1r (see FIG. 4) on the rear side in the traveling direction is retracted, as shown in FIG. 5, the groove width Wr of the retracted torch tip is the front torch tip. The groove width Wf is larger by δ. Therefore, when welding with the torch 1a on the front side, as shown in FIG. 6, a reciprocating motion corresponding to the weaving width Wf required for the front torch is given on the robot side (FIG. 6 (a)), and this is synchronized. A reciprocating motion with an amplitude δ in the same direction is generated by the reciprocating cylinder 9, and the rear welding torch 1b is weaved with an amplitude Wr = Wf + δ (FIG. 6 (b)). And Wr. On the other hand, when welding with the welding torch 1b on the front side, as shown in FIG. 7, a reciprocating motion corresponding to the weaving width Wr of the rear welding torch 1a is given on the robot side (FIG. 7 (a)). The reciprocating cylinder 9 gives a reciprocating motion in the opposite direction of the amplitude δ synchronized with the weaving of the robot to control the weaving width Wf = Wr−δ of the front torch 1b to be narrow (FIG. 7B). The welding is performed so that the front and rear torches are weaved with an appropriate width corresponding to the groove width of the tip part of each torch.

As can be understood from the above description, according to the welding head of this embodiment , one welding for retracting one of the torches for welding, and two for forming one pool by bringing two torch tips close to each other. It is possible to switch between welding and two welding where two pools are formed by separating two torch tips by separating the torch tips, and at the time of two weldings, It is possible to finely adjust the entry / exit, and it is also possible to optimize the weaving width of the front and rear torches in the two-pool welding performed by separating the two torches.

As shown in FIGS. 8 to 10 , the two welding torches 1a and 1b can be mounted together via the expansion / contraction cylinders 8a and 8b. 8 is a side view, FIG. 9 is a front view, and FIG. 10 is a plan view. Those of this example, two welding torches 1a, 1b are both telescopic cylinders 4a, 4b and scaling cylinders 8a, it has been attached via 8b, reciprocating cylinder has a provided.

  The cylinder parts of the two expansion / contraction cylinders 8a and 8b are fixed to the first bracket 7 fixed to the shock sensor 6 with the directions of the rods being opposite to each other. L-shaped second brackets 11a and 11b are fixed to the rods of the two expansion / contraction cylinders 8a and 8b, respectively, and the expansion / contraction cylinders 4a and 4b are fixed to surfaces facing the torch side of the second brackets 11a and 11b, respectively. ing. The fixing structure of the welding torches 1a and 1b to the telescopic cylinders 4a and 4b is the same as that of the first embodiment.

In the above structure SL, the expansion contraction cylinder 8 2 provided, since it is possible to movement away from the other side to one another, is characterized in that it is possible to spaced wider two welding heads.

Side view showing an example Front view of the same Plan view of the same Schematic front view showing a state in which two-layer overlay welding is performed with two pools by separating the front and rear welding torches Explanatory drawing showing the relationship between the difference in height between the front and rear welding torches and the groove width Explanatory drawing which shows the 1st example which adjusts the weaving width | variety of a welding torch before and behind with a reciprocating device. Explanatory drawing showing the second example Side view showing an example in which two expansion / contraction devices are provided Front view of the same Plan view of the same

Explanation of symbols

1a, 1b welding torch
4a, 4b Telescopic cylinder 8 Expansion / contraction cylinder 9 Reciprocating cylinder δ Deviation of groove width

Claims (3)

In a composite welding head having a plurality of welding torches (1a, 1b) arranged side by side, an expansion / contraction device (8) for expanding / contracting the interval between the plurality of welding torches, and one of the plurality of welding torches with respect to the other And a welding torch (1b) mounted via a reciprocating device (4) for reciprocating in the axial direction of the torch, a reciprocating device (9) for reciprocating in the weaving direction orthogonal to the expanding and contracting direction, and A composite welding head comprising a welding torch (1a) mounted without using such a reciprocating device, wherein the reciprocating device is controlled by an NC device that controls a welding robot . The scaling device (8) comprises a interval of the plurality of welding torch you form a pool on the interval a plurality of the welding torch that form a 1 pool respectively, it is possible to change the torch spacing, wherein Item 2. A composite welding head according to Item 1. A welding method in which the welding head according to claim 1 or 2 is attached to a welding robot controlled by an NC device, and the welding head is moved in the front-rear direction along the welding line of the workpiece. The plurality of welding torches in the movement direction rear side are retracted in the torch axial direction by a predetermined distance with respect to the front side, and the groove width deviation at the front and rear ends of the welding torch caused by the retraction ( the welding torch mounted through the reciprocating device with an amplitude corresponding to [delta]) in synchronization with the Uibingu operation of the robot, characterized in that to forward backward, the welding method using a plurality torch.

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