JP2008043972A - Laser beam welding method and equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam welding method and laser beam welding equipment for excellently welding a plurality of overlapped plates by forming an adequate space between the plurality of overlapped plates. <P>SOLUTION: The laser beam welding method for welding the plurality of plates 3, 4 including a steel plate having a coating film on its surface is characterized in that one plate 3 is locally brought into contact with the other plate 4, at least any one of the plate 3 and the other plate 4 is pressed and subjected to the elastic deformation at a part separate from the contact part, thereby a space 7 to be gradually increased in size from a part of the contact part 7 is formed between the plates 3, 4, and the two plates 3, 4 are laser beam-welded by irradiating an area of the space 7 with laser beam. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser welding method and apparatus that welds a plurality of stacked plate materials positively by positively forming a gap therebetween, and particularly to a technique suitable for welding by a remote laser welding method. is there.

  The laser welding equipment used in the mass production process uses, for example, a multi-degree-of-freedom welding robot as a welding machine and a laser processing head (welding torch) at the tip of the welding robot, while being able to transmit with a fiber cable. The mainstream is that the laser beam is irradiated from the machining head to the welded part using a laser beam or the like. However, for example, when welding points are scattered over a wide range, it takes time to move the machining head, and it is not possible to cope with welding at a site where the machining head interferes, such as a narrow groove.

  Therefore, in recent years, a relatively long-focus laser beam (laser beam) is reflected by an optical deflection optical system composed of a plurality of mirrors, and the angle of the mirror of the optical deflection optical system is variably controlled, so that the laser beam is controlled. A technique called a remote laser (scanner laser) welding method that has been moved to the next welding point instantaneously to perform the next welding, and also allows the focal length to be adjusted for each welding point (see below) (See Patent Documents 1 and 2).

  In general, when laser welding is performed on a galvanized steel sheet as a workpiece of an automobile body, the zinc layer between the workpieces is evaporated and scattered by the heat of the laser beam, resulting in welding defects. In order to prevent this, a technique of providing an appropriate gap between the steel plates and discharging the evaporated gas is used.

  This gap is generally installed in the form of an emboss. For example, an emboss is attached to one side of one plated steel sheet and overlapped with the other plated steel sheet, and a necessary gap is created by the height of this emboss ( See Patent Document 3 below).

However, it is very difficult to obtain a necessary gap (for example, 0.2 mm) by always processing the height of the embossment to be constant. Depending on the method of processing, the gap may not be created by embossing. Further, since the height of the emboss and the gap are created in a one-to-one relationship, the variation in the height of the emboss becomes the variation in the gap as it is, and there is a problem that the strength of the welded portion is reduced. .
Japanese Patent Laid-Open No. 10-216980 Japanese Patent Laying-Open No. 2003-145285 (FIG. 1) JP 2001-162388 A

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a laser welding method in which an appropriate gap is formed between a plurality of stacked plate materials and welding is performed favorably. To provide an apparatus.

  In order to achieve such an object, the laser welding method of the present invention is a laser welding method for welding a plurality of plate materials including a steel plate having a coating on the surface thereof, wherein one plate material is locally brought into contact with the other plate material. And at least one of the one plate member and the other plate member is pressed and elastically deformed at a part away from the contact point, and gradually increases from a part of the contact point between the one and the other plate member. A gap is formed, and the plurality of plate members are welded by irradiating a laser beam to the area of the gap.

  Further, the laser welding apparatus of the present invention is a laser welding apparatus for performing welding by irradiating a plurality of plate materials including a steel plate having a film on the surface, and performing welding. A holding means for holding one formed plate material in a state of being overlapped with the other flat plate material, and formed between the bulging portion and the bulging portion by overlapping the one and the other plate material. In the hollow portion, at least one of the two plate members and the other plate member is pressed from the outside, thereby elastically deforming the other plate member toward the one plate member, and A pressing means that forms a gap that gradually increases from a part of a contact portion where the bulging portion contacts the other plate material between the other plate materials, and a movement amount when the pressing means performs a pressing operation; Define the lower limit of the gap. It has a stopper mechanism, and a laser device for irradiating a laser beam to the area of the gap which is characterized in that.

  In the laser welding method and apparatus of the present invention, at a part away from a part where a gap is to be formed, at least one of the contacted plate members is pressed, elastically deformed in an arc shape, and floated from another plate member Thus, a gap that gradually increases from a part of the contact portion is formed between the elastically deformed plate material and the plate material adjacent thereto. The degree to which the elastically deformed plate material is separated from the adjacent plate material can be easily adjusted by adjusting the force pressing the plate material. Therefore, for example, a desired gap for releasing gasified zinc to the outside can be stably and easily formed between the plurality of plate members at the welding site.

  Embodiments according to the present invention will be described below with reference to the drawings.

<First Embodiment>
A laser welding apparatus according to the first embodiment of the present invention is shown in FIG. Reference numeral 2 denotes a workpiece made of a plurality of plate materials including a steel plate having a film on the surface. In this laser welding apparatus, the workpiece 2 is composed of two plate materials 3 and 4 made of galvanized steel plates, and the two plate materials 3 and 4 are held in an overlapping manner and irradiated with a laser beam 1 from the laser device. And welding is performed.

  Although not shown, the laser device includes a laser oscillator of a YAG laser, a robot hand driven by a 6-axis motor, and an optical head attached to the tip thereof. The optical head is attached to an optical fiber cable. The laser head is connected to a laser oscillator so that a long-focus laser beam 1 is emitted from the optical head. Further, an optical deflection optical system (scanner) for deflecting the emission direction of the laser beam 1 is provided inside the optical head, whereby the laser beam 1 is scanned along a predetermined welding locus to form a welding pattern. It has a configuration to be drawn.

  Of the two upper and lower plate members 3 and 4 as the workpiece 2, one plate member (upper plate member) 3 is a galvanized steel sheet in which two or more bulged portions 3a (see FIG. 2) each having a flat surface are formed. The other plate (lower plate) 4 is a flat galvanized steel plate. The two plate members 3 and 4 are overlapped so that the bulging portion 3a is on the inside, and the bulging portion 3a of the upper plate member 3 is held in contact with the lower plate member 4 by a holding means (not shown). Is done. At this time, a trapezoidal cavity 5 is formed between the bulging portion 3 a and the bulging portion 3 a of the upper plate 3 and between the flat lower plate 4.

  In the laser welding apparatus, the lower plate 4 is relatively pressed toward the upper plate 3 and elastically deformed in the hollow portion 5, and the bulging portion 3 a is interposed between the two plates 3 and 4. 4 is provided as a pressing means for forming a gap 7 that gradually increases from a part of the contact portion 6 in contact with 4, and a clamping means 8 for clamping the plate members 3 and 4 from the outside.

  As can be seen from FIG. 1, the clamp means 8 includes a lower gauge member 9, a swingable upper clamp member 10, and an air cylinder 11 that drives the clamp member 10. The upper clamp member 10 and the lower gauge member 9 are bent inward so as to face each other in the vertical direction, intersect with each other at their respective corners, and are pivotally connected by a shaft 12. That is, the upper clamp member 10 has an ear 13 near the lower end, and the ear 13 is pivotally attached to the upper corner of the gauge member 9 by the shaft 12. The air cylinder 11 is pivotally attached to the middle of the gauge member 9 by a shaft 14, and the rear end of the piston rod 15 of the air cylinder 11 is pivotally attached to the rear end of the upper clamp member 10 by a shaft 16.

  With this structure, when the air cylinder 11 is operated, the piston rod 15 is pushed out, the upper clamp member 10 is rotated around the shaft 12, the tip of the clamp member 10 is lowered, and the lower gauge member The workpiece 2 is sandwiched between the two. At this time, the lower gauge member 9 applies a pressing force to the lower plate member 4 as a reaction force of the pressing force from the clamp member 10 and elastically deforms it. In addition, the action part 17 (gauge main-body part) of the gauge member 9 is comprised as an adjustable gauge which can adjust the height.

  Further, a stopper member 18 that restricts a moving amount when the clamp member 10 as the pressing means performs a pressing operation and defines a lower limit value of the gap 7 is provided at a portion in the vicinity of the shaft 12 on the top surface of the gauge member 9. It is provided at a height of 5 to constitute a stopper mechanism.

  FIG. 3 shows a laser welding method. In FIG. 3A, the upper plate 3 is superposed on the lower plate 4, and the bulging portion 3a of the upper plate 3, more precisely the flat surface of the top, is in surface contact with the lower plate 4. In addition, a state in which the cavity 5 is formed between the bulging portion 3a and the bulging portion 3a is shown.

  In the clamp means 8, the upper clamp member 10 applies a downward pressing force to the upper plate member 3, and the lower gauge member 9 applies a push-up force to the lower plate member 4 as a reaction force. As a result, as shown in FIG. 3 (b), the clamping means 8 presses the portions of the upper plate member 3 and the lower plate member 4 corresponding to the cavity 5 in the direction of interfering with each other from above and below. Then, the lower plate member 4 made of a simple flat plate is weaker than the upper plate member 3 at the portion corresponding to the cavity 5, so that the lower plate member 4 is elastically deformed toward the upper plate member 3 to be convex. A gap 7 that is curved and gradually increases from a part of the contact portion 6 is formed between the upper and lower plate members 3 and 4.

  In the case of this embodiment, “part of the contact portion” means a peripheral edge 6 a of a flat surface that forms the top of the bulging portion 3 a of the upper plate 3, and the peripheral 6 a and the lower plate 4 The lower plate 4 is curved so that it hangs away from the upper plate 3 with the corner with the flat surface as a fulcrum, and the gap 7 gradually increases from the peripheral edge 6a.

  The amount by which the lower plate member 4 is pushed up and elastically deformed, that is, the push-up amount by the gauge member 9, is preferably 50% to 150% of the thickness of the lower plate member 4 to be elastically deformed. The reason is that if the plate is pushed up to a range exceeding 150% of the plate thickness of the lower plate 4, the gap 7 between the plates becomes too large and an unwelded state occurs. Further, when the pushing amount is less than 50% of the plate thickness, the gap 7 is not substantially formed, the gasified zinc is not released to the outside, blown off the molten pool and blow holes are generated, and the strength of the welded portion is reduced. Because it invites.

  The advantage of the method of forming the gap 7 described above is that the lower plate 4 is located at a portion corresponding to the cavity 5 away from the contact location 6 of the two plates 3 and 4, that is, at a location away from the location where the gap 7 is to be formed. Is pressed and elastically deformed, so that the pressure adjustment is easier and the desired gap 7 can be stably formed as compared with the type in which the portion where the gap 7 is to be formed is directly pressed.

  Laser welding is performed by irradiating the welded portion 19 of the plates 3 and 4 of the workpiece 2 clamped in this manner with the laser beam 1. Each laser welding is performed in a loop shape from a welding start point to a welding end point, and along a welding locus in which the welding start point and the welding end point do not overlap. Examples of welding trajectories that are loop-shaped and in which the welding start point and the welding end point do not overlap are welding trajectories such as a C shape, an S shape, and a round shape. A weld bead is formed. The reason why the welding start point and the welding end point are not overlapped is that if they overlap, they may melt and open holes. And when forming such a weld bead, the direction in the welding surface of patterns, such as C shape of a welding locus, is set from the one where the welding start point of the said welding locus is the smaller gap 7 between plate materials 3 and 4. Set to start. If set in this way, welding between the plate materials 3 and 4 having a wider gap 7 can be performed as compared with the case where the welding start point of the welding locus is set to start from the larger gap 7 between the plate materials 3 and 4. Become.

  Here, the condition of moving the laser beam 1 from the smaller one of the gaps 7 between the plate members 3 and 4 toward the larger one is that the welding direction at the time of starting laser welding (direction at the welding start point). It has a great meaning, and after laser welding is started, the gap 7 may be welded in a direction from small to large as viewed roughly. In laser welding, since there is no melted portion at the welding start point, cracks are likely to occur, and since there is no melted portion at the welding end point, depressions and defects are likely to occur. However, during the course from the welding start point to the welding end point, there is a melted part around the laser irradiation position, and this promotes the melting of the adjacent part while flowing out. Is called. Therefore, after the laser welding is started, it is assumed that the laser beam 1 has passed through a path in which the magnitude relationship of the gap 7 is locally reversed (gap 7 is large to small) in the middle of the welding trajectory. Even good quality welding is ensured.

  Therefore, when there is a magnitude relationship between the gaps 7 between the steel plates in the part to be laser welded, a welding start point is set to the smaller one of the gaps 7 between the plate members, and the gap 7 is small as a whole. Welding is performed by scanning the laser beam 1 toward the larger side.

  The type of laser used here is a YAG laser, but it may be a carbon dioxide laser. An inert gas such as Ar or He can also be used as the assist gas. In addition, as a basic welding method, a remote laser welding method capable of instantaneously moving the laser beam 1 will be described below, but the present invention is not necessarily limited to the remote laser welding method.

  In the said embodiment, there is no restriction | limiting in particular in the shape of the action surface of the gauge member 9, ie, the top surface of the gauge main-body part 17, It can be set as arbitrary cross-sectional shapes. However, the gauge member 9 is a member that functions to push the lower plate member 4 upward from below and to curve the lower plate member 4 upwardly. Therefore, in order to easily achieve this bending action, the top surface of the gauge main body portion 17 is formed on a curved surface 20 whose top surface is curved convexly as shown in FIG. Is preferred. This is because the lower plate member 4 starts to be bent even in the region of the curved surface 20 and can be bent more greatly.

  Further, as shown in FIG. 5, the effect of promoting the elastic deformation of the lower plate material 4 is the same as that of the upper plate material 3 that is not elastically deformed. It can also be achieved by making it thin.

<Second Embodiment>
FIG. 6 shows a second embodiment of the laser welding apparatus of the present invention. In this laser welding apparatus, the first clamping means 8A that holds the two plates 3 and 4 at the first location in a state where the two plates 3 and 4 are overlapped, and the two plates 3 and 4 that are held at the first location. Among them, one upper plate 3 is in a free state, and only the other lower plate 4 is held at the second location, and the first clamping portion 8B between the first location and the second location. In the vicinity, the lower plate member 4 is pressed toward the upper plate member 3 to be elastically deformed to form a gap 7 that gradually increases from the first location between the two plate members 3, 4. Have

  In this embodiment, the two plate members 3 and 4 are clamped by the first clamping means 8A on one side of the contact portion 6 where the two plate members 3 and 4 are brought into surface contact. Further, at a position away from the other side of the contact location 6 in the direction away from the clamping position, only the lower plate member 4 is clamped by the second clamping means 8B, and the upper plate member 3 is free. Under this state, the lower plate member 4 is pressed toward the upper plate member 3 by the push-up member 21 in the region between the one side and the other side in the contact location 6. In this way, only the lower plate 4 is elastically deformed into an upwardly convex arc shape, and a gap 7 is formed between the two plates 3 and 4.

  Therefore, by irradiating the two plate members 3 and 4 with the laser beam 1 at the portion where the gap 7 exists, the zinc vapor is released from the gap 7 and the strength of the welded portion 19 is not reduced. The plate members 3 and 4 can be laser-welded.

  Although the case where the lower plate member 4 is relatively pushed up and elastically deformed has been described in the above embodiment, the present invention is not limited to this. The present invention can be applied as long as at least one of adjacent plate materials among a plurality of plate materials including a steel plate having a clothing on the surface is elastically deformed. That is, in the present invention, there are a form in which either one of the upper plate member 3 and the lower plate member 4 is elastically deformed, a form in which both the upper plate member 3 and the lower plate member 4 are elastically deformed, and the amount of deformation is different. included.

  The present invention can be used for laser welding.

It is the schematic of the laser welding apparatus of this invention. It is a perspective view which shows the laser welding method of this invention. The procedure of the laser welding method of this invention is shown, (a) is a figure which shows the state which accumulated two board | plate materials, (b) is a figure which shows the state which pushed up the lower board | plate material and was elastically deformed. . It is the figure which showed the modification of the laser welding method of this invention. It is the figure which showed the other modification of the laser welding method of this invention. It is the figure which showed the other laser welding method of this invention.

Explanation of symbols

Laser beam 1
2 work,
3 One plate (upper plate),
3a bulge,
4 The other plate (lower plate),
5 cavity,
6 points of contact,
7 Clearance,
8 Clamping means,
8A first clamping means,
8B second clamping means,
9 gauge members,
10 Clamp member,
18 stopper member,
20 curved surface,
21 Push-up member.

Claims (12)

In the laser welding method of welding a plurality of plate materials including a steel plate having a film on the surface,
One plate is brought into local contact with the other plate,
By pressing and elastically deforming at least one of the one plate material and the other plate material at a site away from the contact location, a gap gradually increasing from a part of the contact location is formed between the one and the other plate material. Forming,
Welding the plurality of plate materials by irradiating the gap area with a laser beam,
And a laser welding method. In the laser welding method of welding a plurality of plate materials including a steel plate having a film on the surface,
Forming a bulging portion having a flat top surface on one of the plurality of plate members;
The one plate material is overlaid on the other plate material so that the bulging portion contacts the other plate material,
By pressing and elastically deforming at least one of the one plate member and the other plate member at a portion away from the contact location between the two plate members, the contact portion gradually increases from a part of the contact portion between the one and the other plate members. Forming a gap
Welding the plurality of plate materials by irradiating the gap area with a laser beam,
And a laser welding method. In the laser welding method of welding a plurality of plate materials including a steel plate having a film on the surface,
One or more of the plurality of plate members is formed with two or more bulging portions having a flat top.
The one plate material is overlapped with the other plate material so that the bulging portion is in contact with the other plate material and a cavity is formed between the bulging portions,
By pressing and elastically deforming at least one of the one plate member and the other plate member in the hollow portion, a gap gradually increasing from a part of the contact location is formed between the one and the other plate member,
Welding the plurality of plate materials by irradiating the gap area with a laser beam,
And a laser welding method.   4. The laser welding according to claim 3, wherein an amount of the one plate member that is elastically deformed by pressing at least one of the other plate members is set to 50% to 150% of a thickness of the pressed plate member. Method. In one side of the contact location that is locally contacted, clamp the overlapping portion of the one and the other plate material,
In addition, in a position away from the one side of the contact location, only the other plate material is clamped and the one plate material is free,
The gap is formed between the one plate and the other plate by pressing and elastically deforming the other plate toward the one plate in a region between the one side and the other side at the contact location. ,
The laser welding method according to claim 1.   6. The laser according to claim 1, wherein the plate thickness of the other plate member is made thinner than the plate thickness of the one plate member to promote elastic deformation of the other plate member. Welding method.   The laser welding method according to claim 1, wherein the laser beam is moved by moving the laser beam from a smaller one to a larger one.   8. The laser welding according to claim 1, wherein the laser welding is remote laser welding in which a long-focus laser beam is deflected by an optical deflection optical system and guided along the welding locus. Method. In a laser welding apparatus for performing welding by irradiating a laser beam toward a plurality of plate materials including a steel plate having a film on the surface,
Holding means for holding one plate material in which two or more bulging portions each having a flat top portion are formed on the other flat plate material;
In a hollow portion formed between the bulging portion and the bulging portion by overlapping the one and the other plate materials, at least one of the one plate material and the other plate material is pressed from the outside. Thus, the other plate member is elastically deformed in a convex manner toward the one plate member, and between the one and the other plate member, the bulging portion gradually increases from a part of a contact portion where the other plate member contacts the other plate member. Pressing means for forming a gap,
A stopper mechanism that limits the amount of movement when the pressing means performs a pressing operation, and defines a lower limit value of the gap;
A laser device for irradiating a laser beam to the gap area;
A laser welding apparatus characterized by that.   The pressing means supports the clamp member that moves from above toward the one plate member and the other plate member from below, and presses the pressing force from the clamp member against the other plate member as a reaction force to elastically deform the other plate member. 10. The laser welding apparatus according to claim 9, comprising a clamping means having a positioning gauge member, wherein a top portion of the gauge member is formed as a convex curved surface on the plate material side. In a laser welding apparatus that performs welding by irradiating a laser beam toward a plurality of plate materials including a steel plate having a film on the surface,
A first clamping means for holding the first plate member and the other plate member in a state of being overlapped with each other;
Of the plate members held at the first place, one plate member is in a free state, and the second clamp means for holding only the other plate member at the second place;
In the vicinity of the first location between the first location and the second location, the other plate material is pressed against the one plate material to be elastically deformed, and between the one plate material and the other plate material, A pressing means for forming a gap that gradually increases from the first location;
A laser device that irradiates the region where the gap is formed with a laser beam,
A laser welding apparatus characterized by that.   The laser according to any one of claims 9 to 11, wherein the plate thickness of the other plate member is made thinner than the plate thickness of the one plate member to promote elastic deformation of the other plate member. Welding equipment.

Images