JP2009056508A - Welding method and laser machining head for welding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which can suppress the generation of strain on the surface caused by concentration of crease or stress in brazing at a roof-side part of a roof panel. <P>SOLUTION: Laser brazing for the front end part 1a and the rear end part 1b of the roof panel 1 is performed, and subsequently the laser brazing for joining both roof-side parts 1c with a roof-side rail is performed. At that time, as shown by arrows PL1, PR1, the brazing on a first pass is performed as the center part in the longitudinal direction of the roof-side part 1c the terminal point, and subsequently as shown by arrows PL2, PR2, the brazing on a second pass is performed same as the center part in the longitudinal direction the terminal point. As a result, crease or stress accompanying the brazing is widely distributed in the center part of the roof panel 1, thereby suppressing the strain on the surface. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a welding method and a laser processing head for welding, for example, a welding method in consideration of suppression of welding distortion when performing continuous welding using laser light, and a laser processing head suitable for the welding.

  Here, the term “welding” is used in a broad sense and includes so-called brazing such as brazing or soldering.

  When replacing a part of the body panel from a steel plate to an aluminum-based metal plate for the purpose of reducing the weight of an automobile body, the dissimilar metal of the steel plate and the aluminum-based metal plate is melted instead of the rivet or mechanical clinch method. Adoption of a brazing method that melts and brazes a metal wire as a material is being studied. Here, the brazing method is said to be suitable as a method for joining an iron-based metal and an aluminum-based metal because sufficient strength and rigidity can be obtained by continuous joining and there are few restrictions due to the structure itself.

  On the other hand, since the amount of deformation due to heat is larger than that of iron, aluminum-based metal cannot sufficiently suppress deformation only by using joining conditions and jigs similar to those of iron-based metal.

Therefore, as a countermeasure against such welding distortion, for example, as described in Patent Document 1, in addition to a method of applying a so-called reverse strain, as described in Patent Document 2, strain removal is performed immediately after friction welding of an aluminum-based metal plate. A method of removing strain with a machine has been proposed.
JP 2001-71130 A Japanese Patent Laid-Open No. 10-305372

  However, in the technique described in Patent Document 1, in addition to the large, expensive, and complicated equipment, in addition to the case of a flat plate material, welding distortion is expected in advance for a highly rigid part such as a vehicle body panel. It is difficult to give reverse strain.

  Further, in the technique described in Patent Document 2, in the case of a flat plate material as described above, even if it is possible to remove the strain after welding, it is highly rigid like a vehicle body panel as described above. It is difficult to remove the welding distortion of a part after welding.

  The present invention has been made paying attention to such a problem. For example, when welding relatively rigid panels such as a body panel of an automobile, reverse strain is applied or strain is removed as in the prior art. It is an object of the present invention to provide a welding method and a laser processing head for welding which are considered so as to suppress the deformation of the base material due to heat, that is, the generation of the welding distortion itself, without performing the above.

  The invention according to claim 1 is a method of performing continuous welding on at least one side of a substantially rectangular workpiece in which at least each of the four corners is constrained by the mating member by joining, and the length of the one side is After welding from one end of the direction toward the longitudinal center, welding is performed from the other end in the longitudinal direction of the one side toward the longitudinal center, and the longitudinal center of the one side is the weld bead. It is characterized in that welding is performed so as to be a joining portion.

  The welding is performed by, for example, a laser processing head held by an industrial robot, and a welding wire is used together as a filler material. At the same time, the welding also includes brazing using a brazing material wire as a welding wire. It is a waste.

  Further, the combination of the counterpart member and the workpiece is, for example, a combination of dissimilar metals of iron-based metal and aluminum-based metal. More specifically, for example, the counterpart member is a roof rail made of a steel plate in a vehicle body of an automobile It is assumed that the work is a roof panel made of an aluminum alloy.

  Therefore, in at least the first aspect of the invention, after welding from one end in the longitudinal direction of one side portion of the substantially rectangular workpiece toward the central portion in the longitudinal direction, the longitudinal direction starts from the other end in the longitudinal direction of the one side portion. Welding toward the center in the direction is nothing but continuous welding with a highly restrained part as the welding start point and a less constrained part as the welding end point. As a result, it is possible to suppress or reduce the occurrence of distortion on the workpiece surface of the weld trace by dispersing wrinkles and stresses concentrated on the end portion of the welding.

  The invention according to claim 7 is a laser processing head used for laser welding including the welding according to claim 1, wherein the laser processing head has a function of irradiating at least a welding point on the workpiece with laser light. In addition to this, a wire supply nozzle for supplying a welding wire toward the welding point from the front side in the welding direction is provided, and when the direction of the welding progress direction is changed in the welding direction, the welding direction is directed toward the welding point from the front side in the welding direction. The direction of the wire supply nozzle is switched so that the welding wire can be supplied.

  Therefore, in the invention according to claim 7, when welding is performed by changing the direction of the welding progress direction in the welding direction with a single laser processing head, the direction of the wire supply nozzle is switched accordingly. In any direction of welding, the welding wire can always be supplied from the front side in the welding direction toward the welding point.

  According to the first aspect of the present invention, the welding is performed so that the center of the longitudinal direction of the specific side portion with relatively weak restraint becomes the end point of welding instead of the four corners with relatively strong restraint among the workpieces. As a result, wrinkles and stresses concentrated at the end of welding can be dispersed to suppress or reduce the occurrence of distortion on the workpiece surface of the weld trace.

  According to the seventh aspect of the present invention, when the direction of the welding progress direction is changed in the welding direction, the direction of the wire supply nozzle is changed accordingly. A welding wire can always be supplied from the front side in the welding direction toward the welding point, and welding can be performed under the same conditions even if the welding direction changes, which contributes to improvement in welding quality.

  FIGS. 1 to 7 are views showing a more specific embodiment of the present invention. As shown in FIGS. 1 and 2, the joint flange portion of the roof panel 1 of the automobile along the roof side rails 4 on both sides is shown. 3 shows an example in which 3 is joined to the roof side rail 4 by a brazing method.

  As shown in FIGS. 1 and 2, a substantially rectangular roof panel 1 constituting a part of a car body of an automobile is made of an aluminum alloy, and a sunroof opening 2 is formed at the center thereof. ing. The roof panel 1 has a front end 1a as a front end thereof joined to a front roof rail (not shown) and a rear end 1b as a rear end joined to a rear roof rail (not shown) by brazing. In the roof side portions 1c on both sides, the joining flange portions 3 along the roof side rails 4 are joined to the roof side rails 4 made of steel plate by brazing. In addition, the brazing bead part which is a weld bead is shown with the code | symbol Br in the same figure.

  As is well known, the roof side rail 4 is formed in advance as a closed cross-sectional structure having an outer panel 4a, an inner panel 4b, and a reinforcement 4c, and is formed between the joint flange portion 3 on the roof panel 1 side and the outer panel 4a. While forming the groove portion 5, the joining flange portion 3 on the roof panel 1 side is joined to the outer panel 4a with a continuous bragging bead portion Br.

  As a procedure for brazing, brazing of the joint flange portion 3 of the roof side portion 1c is performed after brazing the front end portion 1a and the rear end portion 1b of the roof panel 1. Particularly for brazing at the joint flange portion 3, a laser processing head 6 as shown in FIG. 3 is supported on the tip of an arm 13 of an industrial robot (hereinafter simply referred to as a robot) 7, for example. Brazing is performed while the head 6 is continuously moved at a predetermined speed along the groove 5 in FIG.

  As is well known, the laser processing head 6 shown in FIG. 3 condenses laser light introduced by an optical fiber 8 or the like into a predetermined spot diameter and then irradiates the joining flange portion 3 as laser light La. In addition to the head body 9 having a built-in system, a pressure roller 10 that can be rotated as pressure means for correcting pressure by restraining the vicinity of the brazing position and a brazing material (welding wire) A wire supply nozzle 12 for supplying a material wire (filler wire) 11 toward the brazing position is provided. The laser processing head 6 has an axis 14a of the pivot shaft 14 at the tip of the arm 13 (this axis 14a is parallel to the optical axis of the laser beam La), in addition to the degree of freedom by driving each joint of the arm 13. It is possible to swing by 180 ° in the direction of arrow M around the rotation center.

  Then, as shown in FIG. 2, the pressure roller 10 is pressed against the joining flange portion 3 superimposed on the outer panel 4a of the roof side rail 4, and the laser processing head 9 is continuously moved at a predetermined speed along with the irradiation of the laser beam La. Since the pressure roller 10 rolls on the joint flange portion 3 and the joint flange portion 3 is pressed and restrained, the filler wire 11 is continuously fed from the wire supply nozzle 12 toward the laser beam irradiation position at the same time. Brazing while feeding out. In this case, the filler wire 11 is always supplied from the front side in the brazing traveling direction toward the laser beam irradiation position which is a welding point or a joint point.

  Here, as shown in FIG. 4, as shown by the arrow P1 for both roof side portions 1c, for example, from the rear end portion 1b side to the front end portion 1a side of the roof panel 1, or as indicated by the arrow P2. Conversely, it is efficient to perform brazing by moving the laser processing head 6 simultaneously and in the same direction from the front end portion 1a side to the rear end portion 1b side of the roof panel 1. However, the front end portion 1a and the rear end portion 1b of the roof panel 1, especially the four corners of the roof panel 1, have already been brazed and the parts are restrained by freezing of the so-called joined state. If brazing is performed with the corner portion of the front end portion 1a or the rear end portion 1b of the finished roof panel 1 being the end point of brazing, the brazing end point position cannot be dispersed with concentration of wrinkles and stress, resulting in brazing. Strain may occur on the surface of the subsequent roof panel 1.

  Therefore, in the present embodiment, as indicated by arrows P1 and P2 in FIG. 4, the roof panel 1 of both the roof side portions 1c is directed, for example, from the front end portion 1a side to the rear end portion 1b side or vice versa. Instead of brazing in one pass from the rear end portion 1b side of the roof panel 1 toward the front end portion 1a side, as shown by arrows PL1 and PR1 in the figure, for example, on the rear end portion 1b side of the roof panel 1 When the brazing is started toward the front end portion 1a side with the brazing start point as the starting point, the first pass brazing is finished once with the longitudinal intermediate portion of the roof side portion 1c as the brazing end point. Then, the second pass of brazing is started toward the rear end 1b side as indicated by arrows PL2 and PR2 with the front end 1a side of the roof panel 1 as the starting point of brazing, and the longitudinal direction of the roof side portion 1c is intermediate. The brazing of the second pass is finished with the part as the end point of the brazing. In this case, the brazing bead portions Br of the first pass and the second pass are merged at the brazing end point position. It is desirable to overlap each other over a predetermined length.

  More specifically, as shown in FIGS. 5 and 6, two robots 7A and 7B are arranged opposite to each other so as to be almost symmetrical on both sides of the roof panel 1, and one robot 7A includes one robot 7A. The roof side portion 1c is brazed for the first pass indicated by the arrow PL1 from the rear end portion 1b side to the front end portion 1a side, and at the same time, the other robot 7B has the other roof side portion 1c. Similarly, the first pass brazing indicated by the arrow PR1 is performed from the rear end portion 1b side to the front end portion 1a side.

  Thus, after brazing for the first pass at both roof side portions 1c, that is, brazing indicated by arrows PL1 and PR1, the robots 7A and 7B are exchanged between the left and right roof side portions 1c and 1c. The movement trajectories for replacement by the robots 7A and 7B at this time are indicated by reference characters PL3 and PR3 in FIG. Then, in each of the robots 7A and 7B, the laser processing head 6 is swung by 180 ° using the degree of freedom of the turning shaft portion 14 shown in FIG. For the roof side portion 1c opposite to the eyes, the second robot 7B is brazed as indicated by an arrow PR2 from the front end portion 1a side to the rear end portion 1b side. Similarly, the second side brazing indicated by the arrow PL2 is performed on the roof side portion 1c opposite to the first pass from the front end portion 1a side toward the rear end portion 1b side.

  As described above, the laser processing head 6 is swung and swung while the robots 7A and 7B are exchanged. The first pass is indicated by arrows PL1 and PR1, and the second pass indicated by arrows PL2 and PR2. This is to make the processing conditions the same during brazing. That is, at the time of the first pass brazing indicated by the arrows PL1 and PR1 and at the time of the second pass brazing indicated by the arrows PL2 and PR2, as described above, the wire feed nozzle 12 is always applied from the front side of the brazing direction. It is necessary to supply the filler wire 11 at the same time, and at the same time, as a relationship between the pressure roller 10 and the irradiation position of the laser beam La, there is an irradiation position of the laser beam La outside the pressure roller 10 in the vehicle width direction. This is because it is a condition.

  As described above, when brazing the roof side portion 1c of the roof panel 1 following the brazing of the front end portion 1a and the rear end portion 1b of the roof panel 1 already joined and restrained to the front roof rail and the rear roof rail. After the first pass brazing indicated by arrows PL1 and PR1 from one end in the longitudinal direction toward the center in the longitudinal direction, the arrow from the other end in the longitudinal direction of the roof side portion 1c toward the center in the longitudinal direction When the second pass of brazing indicated by PL2 and PR2 is applied, wrinkles and stresses are gathered in the central portion in the longitudinal direction of the roof panel 1 as the brazing progresses. Since the degree of restraint by joining is lower than that of the four corners, both roof side portions 1c When the brazing is completed, wrinkles and stress can be dispersed over a wide range in the longitudinal center of the roof panel 1, and stress concentration at the part is avoided to generate distortion of the roof panel 1. It will be possible to prevent it.

  Here, FIG. 7 is a view of the roof panel 1 in FIG. 5 as viewed from the rear end portion 1b side. As is apparent from FIGS. 5 and 7, since the brazing work is performed simultaneously in parallel by the two robots 7A and 7B arranged almost symmetrically, the first pass brazing indicated by the arrows PL1 and PR1 is performed. Although there is no particular problem, there is a possibility that the arms 13 and 13 of both robots 7A and 7B interfere with each other when performing the second pass brazing indicated by arrows PL2 and P2 in parallel. Therefore, as shown in FIG. 7, in order to offset the laser processing heads 6 and 6 of both robots 7A and 7B by a predetermined amount in the vertical direction, for example, between the arm 13 of one robot 7B and the laser processing head 6 It is desirable to interpose the extension bracket 14 in the.

  Here, at the time of brazing at the left and right roof side portions 1c of the roof panel 1, in order to make the brazing conditions of the parts indicated by the arrows PL1, PR2 and PL2, PR2 both the same, it is always necessary to wire from the front side of the brazing direction. Irradiation of the laser beam La to the outside of the pressure roller 10 in the vehicle width direction as a relation between the necessity of supplying the filler wire 11 by the supply nozzle 12 and the irradiation position of the pressure roller 10 and the laser beam La. As mentioned above, it is necessary to have a position.

  For this reason, in order to cope with brazing of both roof side portions 1c of the roof panel 1, the laser processing head 6 has a degree of freedom of rotation around the axis 14a in the rotation shaft portion 14 shown in FIG. In addition to the above, two robots 7A and 7B are required as shown in FIGS.

  This is because the direction of the wire supply nozzle 12 is constant with respect to the head body 9 of the laser processing head 6, and the laser processing head 6 has a degree of freedom of rotation about the axis 14a. In addition, if it is possible to switch the direction of the wire supply nozzle 12 in accordance with the moving direction of the laser processing head 6, for example, the first pass indicated by arrows PL1, PR1 and PL2, PR2 in FIGS. It becomes possible to process the brazing of the second pass with one robot.

  8 and 9 show examples of the laser processing head 16 that can change the direction of the wire supply nozzle 12 in accordance with the change in the direction of the brazing direction as described above. The laser processing head 16 is attached to the tip of the arm 13 of the robot 7 via the turning shaft portion 14 instead of the laser processing head 6 of FIG.

  As shown in FIGS. 8 and 9, the laser processing head 16 includes a main body 15 as well as a rotatable pressure roller 17 and a wire supply nozzle 18 as pressure means, as shown in FIG. The pressure roller 17 can be moved up and down, and the wire tube 19 connected to the wire supply nozzle 18 is movable together with the wire supply nozzle 18.

  A substantially L-shaped retainer 20 is attached to the head body 15, and an upper bracket 21 is fixed to the retainer 20. Further, an intermediate bracket 22 is guided and supported on the upper bracket 21 so as to be movable up and down, and a lower bracket 23 is guided and supported on the intermediate bracket 22 so as to be movable up and down. Further, a pressure roller 17 having a substantially truncated cone shape is rotatably mounted on the lower bracket 23 via a shaft 24.

  A compression coil spring 25 that is an elastic body is interposed between the upper bracket 21 and the intermediate bracket 22, and a compression coil spring 26 is also interposed between the intermediate bracket 22 and the lower bracket 23. The intermediate bracket 22 is always urged downward with respect to the bracket 21, and the lower bracket 23 is always urged downward with respect to the intermediate bracket 22. However, the spring force (spring constant) of the compression coil spring 25 is set in advance smaller than the spring force of the compression coil spring 26 below it.

  An arm 27 is guided and supported on the upper bracket 21 so as to be movable up and down, and a rigid wire tube having a wire supply nozzle 18 connected to the tip, for example, a wire tube 19 made of a copper tube is armed via a lower holder 28. 27. A pin 29 protrudes from the upper bracket 21 side, and an elongated guide slot 30 that engages with the pin 29 is formed along the vertical direction on the arm 27 side. The arm 27 is always urged downward by the force of the compression coil spring 32 that is an elastic body interposed between the arm 27 and the upper upper holder 31, but the upper end of the guide slot 30 and the pin 29 The lower limit position of the arm 27 with respect to the upper bracket 21 is regulated by this contact. As a result, the arm 27 can move up and down along the guide slot 30 and can swing around the pin 29 as a rotation center.

  The intermediate bracket 22 is provided with an upper stopper 33 for restricting the upper limit position of the intermediate bracket 22 with respect to the upper bracket 21, and the intermediate bracket 22 has a relative position between the intermediate bracket 22 and the arm 27, That is, a lower stopper 34 for restricting the lower limit position of the arm 27 with respect to the intermediate bracket 22 is provided. As will be described later, even if the intermediate bracket 22 and the lower bracket 23 are relatively moved in the vertical direction, the lower stopper 34 provided on the intermediate bracket 22 is considered not to interfere with the lower bracket 23.

  As shown in FIG. 10 in addition to FIG. 8, the lower holder 28 projects substantially perpendicularly to the front side of the arm 27, and its root side is rotatably connected to the arm 27 by a pin 35. That is, the lower holder 28 can swing in the direction of arrow a with respect to the arm 27 as shown in FIG. An elongated hole-shaped guide slot 36 is formed in the lower holder 28, and the wire tube 19 is loosely fitted in the guide slot 36, that is, is rotatable in the guide slot 36 and along the longitudinal direction of the guide slot 36. It is inserted and supported so that it can be displaced.

  Here, the wire supply nozzle 18 at the tip of the wire tube 19 inserted and supported by the lower holder 28 is always laser light in a state where at least the pressure roller 17 is in pressure contact with the joining flange portion 3 of the roof panel 1 as will be described later. The irradiation position is set so as to be directed (however, in FIG. 8, since the arm 27 is in the neutral position as will be described later, the wire supply nozzle 18 is not directed to the laser light irradiation position). On the other hand, since the arm 27 itself to which the lower holder 28 is attached can swing about the pin 29 as a rotation center, even if the arm 27 itself swings and is displaced, the wire supply nozzle 18 does not move in the movement of the arm 27. It is necessary to follow and direct the laser beam irradiation position.

  Therefore, in the present embodiment, for example, even if the arm 27 itself is oscillated and displaced in either of the front and rear directions as shown in FIGS. 13 and 14 from the neutral position (the state of FIGS. 8 and 9), the wire supply nozzle 18 The wire tube 19 is bent in advance so that the laser beam irradiation position can continue to be directed, and a rotary pipe joint (rotary joint, swivel joint, or swivel joint) as shown in FIG. 37) is interposed. In addition, as shown in FIG. 11, this rotary type pipe joint 37 has a structure in which one joint element 37a and the other joint element 37b are relatively rotatable in a connected state with the wire tube 19. .

  In this manner, coupled with the wire tube 19 being inserted and supported in the guide slot 36 of the lower holder 28 in a loose fit, the wire tube 19 is bent in advance and a rotary tube is inserted in the middle of the wire tube 19. By interposing the joint 37, the wire tube 19 can be displaced following the movement of the arm 27, and the wire supply nozzle 18 at the tip of the wire tube 19 is irradiated with laser light regardless of the displacement position. You can continue to point the position.

  When performing the brazing described above using the laser processing head 16 configured in this way, a wire supply nozzle is provided so that the filler wire 11 can always be supplied from the front side in the brazing traveling direction according to the switching of the brazing traveling direction. The procedure for changing the direction of 18 is shown in FIGS.

  (A-1) and (A-2) in FIG. 12 show the same state as in FIGS. 8 and 9, and as shown in FIG. 12, the laser machining head 16 reaches the brazing start position by the autonomous operation of the robot 7 during brazing. Move. At this time, the intermediate bracket 22 is in the most lowered state with respect to the upper bracket 21, the lower bracket 23 is in the most lowered state with respect to the intermediate bracket 22, and the arm 27 is the most with respect to the upper bracket 21. It is in a lowered state. At the same time, the arm 27 is in a so-called neutral position that is not oscillating and displaced in any of the front and rear directions as shown in FIG.

  9 and 12 (A-1) shows a state at the moment when the pressure roller 17 comes into contact with the joint flange portion 3 of the roof panel 1. From this state, the pressure roller 17 is also operated by the autonomous operation of the robot 7. Is further pressed against the joining flange portion 3, the upper bracket 21 is lowered, and the pressure applied to the joining flange portion 3 by the pressure roller 17 is further increased. Thereby, it correct | amends so that the clearance gap between the joint flange part 3 and the roof side rail 4 may substantially disappear in the site | part which is going to give brazing from now on.

  More specifically, as described above, since the spring force urging the lower bracket 23 downward is larger than the spring force urging the intermediate bracket 22 downward, the pressure roller 17 is moved upward relative to the upper bracket 21 together with the lower bracket 23 and the intermediate bracket 22. When the pressure roller 17 moves to some extent together with the lower bracket 23 and the intermediate bracket 22, as shown in FIGS. 12B-1 and 12B-2, the lower end of the arm 27 is first moved toward the intermediate bracket 22 side. The arm 27 comes into contact with the lower stopper 34 so that the arm 27 is sandwiched between the lower stopper 34 and the compression coil spring 32, and the lower stopper 33 on the side of the intermediate bracket 22 is eventually moved to the lower end of the upper bracket 21 later than that. Will come into contact. With this, at least the relative movement between the upper bracket 21 and the intermediate bracket 22 is prevented.

  When the laser processing head 16 is further pressed, the lower bracket 23 moves upward together with the pressure roller 17 with respect to the intermediate bracket 22 instead, as shown in FIGS. The lower end of the arm 27 which is displaced and is sandwiched between the lower stopper 34 and the compression coil spring 32 comes into contact with the pressure roller 17, and the movement of each part is temporarily stopped.

  In order to perform continuous brazing in this state, for example, when the laser processing head 16 is moved in the right direction of (B-1) in FIG. 12, the pressure roller 17 rolls on the flange portion 3 for convenience. Accordingly, as shown in FIG. 13, due to the frictional force between the pressure roller 17 and the arm 27, the arm 27 swings around the pin 29 in the rolling direction of the pressure roller 17. At the same time, even if the wire tube 19 supported by the arm 27 itself follows the swing displacement of the arm 27 and the arm 27 swings and displaces as shown in FIG. No. 18 can continue to direct the laser beam irradiation position from the front side in the brazing traveling direction.

  More specifically, the wire tube 19 supported by the arm 27 via the lower holder 28 is loosely inserted and supported in a guide slot 36 (see FIG. 10) formed in the lower holder 28, and in the middle. Since the rotation-type pipe joint 37 has a degree of freedom of rotation and the lower holder 28 itself has a degree of freedom of rotation as shown by an arrow a in FIG. Following the displacement, a part of the wire tube 19 turns around the rotary pipe joint 37 as a fulcrum, and finally can be displaced to the position shown in FIG. Therefore, the wire supply nozzle 18 at the tip of the wire tube 19 can continue to direct the laser beam irradiation position from the front side in the brazing traveling direction.

  Also, as shown in FIG. 14, the same behavior can be achieved when the laser processing head 16 is moved in the opposite direction and the pressure roller 17 is rolled in the reverse direction.

  13 and 14, the laser beam La is irradiated from the head main body 15 of the laser processing head 16 while rolling the pressure roller 17, and from the wire supply nozzle 18 toward the laser beam irradiation position. By supplying the filler wire 11 (see FIG. 3) as being fed out, brazing for joining the joining flange portion 3 of the roof panel 1 and the roof side rail 4 can be continuously performed.

  Further, when the laser processing head 16 is lifted away from the joining flange portion 3 when the brazing end point is reached, the state autonomously returns from the state of FIG. 13 or 14 to the state of FIGS.

  As described above, when the laser processing head 16 capable of switching the direction of the wire supply nozzle 18 is used, brazing at either the left or right roof side portion 1c can be processed by a common robot 7. For example, for example, it is possible to perform the second-pass brazing indicated by the arrow PL2 following the first-pass brazing indicated by the arrow PL1 in FIGS. 4 and 6, and the turning around the axis 14a shown in FIG. By using the degree of freedom together, for example, all the brazing of the first pass and the second pass indicated by arrows PL1, PR1 and PL2, PR2 in FIGS. 4 and 6 can be processed by one common robot 7. It becomes.

Explanatory drawing which shows the outline of the roof panel of a motor vehicle as an example of the workpiece | work provided to welding (blazing) in this invention. The expansion explanatory view of the Q section of FIG. The principal part perspective view which shows the laser processing head for brazing. Explanatory drawing of the locus | trajectory in the case of performing the brazing of the roof panel shown in FIG. 1 by dividing into the 1st pass and the 2nd pass. The perspective view which shows the motion of the laser processing head by the robot in the case of performing brazing with the locus | trajectory of FIG. FIG. 6 is an explanatory diagram in which the trajectory of the robot shown in FIG. 5 is superimposed on the trajectory of FIG. Explanatory drawing which looked at the roof panel of FIG. 5 from the rear end part side. Explanatory drawing which shows 2nd Embodiment of the laser processing head which manages brazing. Explanatory drawing of the left side surface of FIG. FIG. 9 is an enlarged explanatory view corresponding to the direction of arrow a in FIG. 8. The expansion explanatory view of the rotation type pipe joint in Drawing 9. FIGS. 8 and 9 are operational explanatory views of the laser processing head, wherein (A-1), (B-1) and (C-1) are front explanatory views, (A-2), (B-2) and (C-2) is a side explanatory view of (A-1), (B-1) and (C-1). Operation | movement explanatory drawing following (C-1) of FIG. Similarly operation explanatory drawing following (C-1) of FIG.

Explanation of symbols

1 ... Roof panel (work)
DESCRIPTION OF SYMBOLS 1a ... Front end part 1b ... Rear end part 1c ... Roof side part (one side part)
3 ... Joint flange 4 ... Roof side rail (mating member)
DESCRIPTION OF SYMBOLS 7 ... Industrial robot 7A, 7B ... Industrial robot 9 ... Head main body 10 ... Pressure roller as pressure means 11 ... Brazing material wire (filler wire) as welding wire
DESCRIPTION OF SYMBOLS 12 ... Wire supply nozzle 15 ... Head main body 16 ... Laser processing head 17 ... Pressure roller as pressure means 18 ... Wire supply nozzle 19 ... Wire tube 21 ... Upper bracket 22 ... Intermediate bracket 23 ... Lower bracket 27 ... Arm PL1 ... First path locus PR1 ... First path locus PL2 ... Second path locus PR2 ... Second path locus La ... Laser light

Claims (10)

A method of performing continuous welding on at least one side of a substantially rectangular workpiece that is to be restrained by a mating member at least at each of the four corners,
After performing welding from one end in the longitudinal direction of the one side toward the longitudinal central portion, performing welding from the other end in the longitudinal direction of the one side portion toward the longitudinal central portion,
A welding method, wherein welding is performed such that a central portion in the longitudinal direction of the one side portion becomes a joining portion of welding beads.   The welding method according to claim 1, wherein the welding is performed by a laser processing head provided to an industrial robot, and a welding wire is used in combination as a filler material.   The welding method according to claim 2, wherein the welding is brazing in which a brazing wire is used as a welding wire.   4. The welding method according to claim 3, wherein the combination of the counterpart member and the workpiece is a combination of dissimilar metals of iron-based metal and aluminum-based metal.   5. The welding method according to claim 4, wherein the counterpart member is a roof rail made of a steel plate in a car body of an automobile, and the work is a roof panel made of an aluminum alloy.   The welding method according to claim 1, wherein the weld beads are overlapped with each other over a predetermined length at a joining portion between the weld beads. A laser processing head used for laser welding,
This laser processing head includes a wire supply nozzle that supplies a welding wire toward the welding point from the front side in the welding direction, in addition to the function of irradiating laser light toward the welding point on the workpiece.
The laser is characterized in that the direction of the wire supply nozzle is switched so that the welding wire can be supplied from the front side in the welding direction toward the welding point when the direction of the welding progress direction is changed in the welding direction. Processing head. The laser processing head includes a rotatable pressure roller that rolls on the workpiece as a pressure means for pressing and restraining the vicinity of the welded portion.
8. The laser processing head according to claim 7, wherein the direction of the wire supply nozzle is switched as the direction of rotation of the pressure roller changes when the direction of the welding progress direction is changed. The welding method according to claim 2,
The laser processing head is capable of swinging at least 180 degrees,
Primary welding that performs welding in parallel in the same direction from one end in the longitudinal direction of each side to the center in the longitudinal direction by an industrial robot independent for each side on the opposite two sides of a substantially rectangular workpiece Process,
The industrial robot that performs welding on each of the two opposing sides is interchanged with the primary process, and each laser processing head is swung 180 degrees, and then the longitudinal direction starts from the other longitudinal end of each side. A secondary welding process in which welding is performed in parallel in the same direction toward the center,
The welding method according to claim 2, comprising:   The welding method according to claim 9, wherein the mounting position of the laser processing head in the height direction with respect to the robot arm is offset between the two industrial robots.

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