JP2006007238A - Weld joint structure by laser welding and laser welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a weld joint structure that enables laser welding to be performed by adding a little improvement to a workpiece end, even if the optical axis of the laser beam and the surface to be welded are in a relation nearly parallel with each other in the laser welding. <P>SOLUTION: This is a weld joint structure in which, of a panel 5 and a reinforcement 6, laser welding is performed on a vertical wall face 5a and a flange part 6a that are parallel or slightly acute-angled with the irradiation direction of the laser beam Lb. In the vertical wall face 5a and the flange part 6a, there are preliminarily bulge-formed the embossed parts 7, 8 containing shelf-like surfaces 7a, 8a which are mutually superimposed and nearly right-angled in surface with the irradiation direction of the laser beam Lb. The laser welding is performed on the shelf-like surfaces 7a, 8a of these embossed parts 7, 8 as the surface to be irradiated with the laser beam. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a welded joint structure by laser welding and a laser welding method, and in particular, a laser beam (laser beam) having a relatively long focal point is reflected by a mirror, and the laser beam is moved instantaneously by variably controlling the angle of the mirror. The present invention relates to a welded joint structure and a welding method suitable for a welding method called a remote laser (scanner laser) welding method in which the next welding is performed.

  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 process head, etc., but if the welding points are scattered over a wide range, for example, it takes time to move the machining head, It is impossible to cope with the welding of a part where the machining head interferes, such as a narrow groove.

Therefore, in recent years, a relatively long focal point laser beam is reflected by a plurality of mirrors, and the angle of the mirror is variably controlled to move the laser beam instantaneously to the next welding point and perform the next welding. A technique called a remote laser (scanner laser) welding method that enables the adjustment of the focal length for each welding point is proposed in Patent Document 1 and the like.
Japanese Patent Laying-Open No. 2003-145285 (FIG. 1)

  The remote laser welding method as described above has the advantage that the laser beam can be instantaneously moved to the next welding point, but the surface to be welded is the optical axis of the moved laser beam as in the case of a general laser welding method. In such a case, welding cannot be performed, and it is necessary to greatly change the workpiece side posture so that the surface to be welded is substantially perpendicular to the optical axis of the laser beam. Therefore, the advantages inherent to the remote laser welding method cannot be utilized, and there is still room for improvement.

  The present invention has been made by paying attention to the above-described problems. In particular, even in the case of laser welding, even if the optical axis of the laser beam and the surface to be welded are substantially parallel, It is an object of the present invention to provide a welded joint structure and welding method capable of performing laser welding with a slight improvement.

  The invention according to claim 1 is a structure of a welded joint in which laser-welded portions are welded to wall surfaces that are parallel to the laser beam irradiation direction or have a minute acute angle among objects to be welded. Protruding part including a shelf-like surface that is substantially perpendicular to the laser beam irradiation direction is formed in advance on the part, and laser welding is performed using the shelf-like surface of this protruding part as the laser beam irradiation surface. To do.

  In this case, as described in claim 2, it is possible to slidably move the overlapping surfaces of the shelf-like surfaces in a direction in which they approach each other. It is desirable to absorb the variation of

  Further, the invention described in claim 5 captures the technique described in claim 1 as a laser welding method, and includes a plurality of wall surfaces that are parallel to the laser beam irradiation direction or have a minute acute angle among objects to be welded. As a method of performing laser welding on the overlapped portion, prior to laser welding, a protruding portion including a shelf-like surface that is substantially perpendicular to the laser beam irradiation direction is formed in advance on the overlapped portion between the wall surfaces. Laser welding is performed using the shelf-like surface of the protrusion as a laser light irradiation surface.

  In this case, as described in claim 6, a plurality of protrusions are set in the overlapping portion of the wall surfaces, and the laser light is reflected by at least two mirrors so that the laser light is reflected on the shelf surface of the protrusion. In the remote laser welding method, the laser beam is instantaneously moved to the shelf surface of the projection, which is the next welding position, by changing the mirror angle while the next welding is performed. It is desirable to be.

  Therefore, in the first and fifth aspects of the invention, when it is clear that the optical axis of the laser beam is substantially parallel to the wall surface of the workpiece during laser welding, As processing, for example, a bead-shaped or embossed-shaped protrusion is bulged and formed in advance. By doing so, at least the shelf-like surface of the projection is substantially perpendicular to the optical axis of the laser beam, and even if welding is performed by remote laser welding, it is possible to reliably weld.

  According to the first and fifth aspects of the present invention, even if the wall surface of the workpiece to be welded is substantially parallel to the optical axis of the laser beam, the shelf surface of the protruding portion is the light beam of the laser beam. Since the relationship is almost perpendicular to the axis, even if it is premised on welding by the remote laser welding method, welding is reliably performed with good welding quality without changing the position of the workpiece. There is an effect that can.

  1 to 3 are diagrams showing a more specific embodiment of the present invention. In particular, FIG. 1 is a schematic configuration of a remote laser welding method, and FIG. 2 is a panel to be welded as an enlarged view of a main part of FIG. Details of each are shown.

  In the remote laser welding method, as shown in FIG. 1, a laser beam Lb oscillated from a laser oscillator 1 is guided to two movable mirrors 3 and 4 by a conduit 2 with a built-in mirror, and these mirrors 3 and 4 are guided. By variably controlling the angle, the laser beam Lb is finally guided to a predetermined welded portion of the panel W which is a workpiece to be welded. Each of the mirrors 3 and 4 has uniaxial or biaxial variable degrees of freedom, and the variable degrees of freedom of these mirrors 3 and 4 are not limited to instantaneous movement of the welded part, but also at a specific welded part. It is used for continuous movement of the laser beam irradiation position. Further, the focal length can be adjusted by moving a lens (not shown) arranged in front of the mirror along the laser optical axis.

  FIG. 2 shows a closed cross section (box cross section) having flange portions 6a and 6b around the entire periphery of the inner corner portion of the lower panel 5 bent in advance in a substantially L shape as the work piece. ) An example in which a reinforcement 6 having a structure is welded and joined by a remote laser welding method using flanges 6a and 6b as welds to form a laser welded joint is shown.

  As shown in FIG. 2, on the premise that the laser beam Lb is irradiated to the panel 5 from above at a predetermined angle, the substantially vertical vertical wall surface 5a of the panel 5 and the reinforcement 6 side are also substantially vertical. When welding the flange portion 6a which is a vertical wall surface, the optical axis of the laser beam Lb and the vertical wall surface 5a and the flange portion 6a are both substantially parallel (including a relationship in which both form a minute acute angle). Therefore, it is difficult to perform laser welding as it is.

  Therefore, as shown in FIG. 3, a plurality of embossed portions 7, 7,. Similarly, a plurality of embossed portions 8, 8... Having a triangular cross section as protrusions that can match the embossed portion 7 on the vertical wall surface 5 a side are bulged and formed in advance by press working. Prior to laser welding, the embossed portions 7 and 8 are matched with each other.

  In this way, the embossed portions 7 and 8 are matched with each other while pressing the reinforcement 6 against the inner corner of the panel 5 and superposing the vertical wall surface 5a on the panel 5 side and the flange portion 6a on the reinforcement 6 side. By doing so, the relative positioning of the panel 5 and the reinforcement 6 is performed.

  Here, the embossed portions 7 and 8 to be bulged and formed in advance on the vertical wall surface 5a and the flange portion 6a have surfaces that are perpendicular to the surface of the laser beam Lb or substantially perpendicular to the surface. This is an absolute condition, and in the present embodiment, the upper surfaces 7a and 8a of the embossed portions 7 and 8 are used as shelf-like surfaces, and the shelf-like surfaces 7a and 8a are overlapped with each other. 7a and 8a are set so as to be substantially perpendicular to the optical axis of the laser beam Lb.

  2 and 3, when the relative positioning between the panel 5 and the reinforcement 6 is performed, the shelves of the embossed portions 7 and 8 on the vertical wall surface 5a side of the panel 5 and the flange portion 6a side of the reinforcement 6 are provided. The surface surfaces 7a and 8a are used as laser light irradiation surfaces, and laser beam Lb is applied to the overlapping portions of the shelf-like surfaces 7a and 8a to perform laser welding. A weld bead portion formed by laser welding is indicated by a symbol Be. That is, the laser beam Lb is sequentially moved to the overlapping portion between the embossed portions 7 and 8 by the remote laser welding method, and laser welding is performed each time.

  In this case, as shown in FIG. 2, if the panel 5 and the reinforcement 6 are relatively slidable in the longitudinal direction of the reinforcement 6, the panel 5 and the reinforcement 6 are caused by a manufacturing error or an assembly error. For example, even if the relative positions of the embossed portions 7 and 8 vary by a predetermined amount a, the superposition state of the shelf upper surfaces 7a and 8a in the embossed portions 7 and 8 can be maintained, and as a result, the variation a is absorbed. It becomes possible.

  In addition, welding at the overlapping portion between the general portion 5b of the panel 5 and the flange portion 6b of the reinforcement 6 can be performed by directly irradiating the flange portion 6b with the laser beam Lb.

  5 to 7 show a second embodiment of the present invention, in which a reinforcement 16 having a closed cross section (box cross section) structure is formed between a pair of vertical wall surfaces 15a and 15a bent on both sides of the panel 15 in the same manner as described above. Is shown in a cross-sectional manner, and flange portions 16a which are vertical wall surfaces at both ends of the reinforcement 16 are welded to the vertical wall surface 15a as welded surfaces.

  In the present embodiment, since the overall length of the reinforcement 16 is set in advance so as to match the span formed by the pair of vertical wall surfaces 15a, 15a on the panel 15 side, the panel 15 as in the previous embodiment. If the embossed portion which is a protrusion is bulged and formed in advance on the flange portion 16a which is the vertical wall surface 15a on the side and the vertical wall surface on the reinforcement 16 side, the reinforcement 16 is set between the pair of vertical wall surfaces 15a and 15a. It becomes difficult.

  Therefore, in the present embodiment, the caulking apparatus 10 is used in combination prior to laser welding, and if relative positioning between the panel 15 and the reinforcement 16 is performed as shown in FIG. Caulking is performed by a caulking device 10 at a plurality of overlapping portions of the wall surface 15a and the flange portion 16a on the reinforcement 16 side, and a plurality of protrusions are provided on both the vertical wall surface 15a and the flange portion 16a as shown in FIG. The crimped embossed portions 17 and 18 having a rectangular cross section are bulged. Since these caulking embossed portions 17 and 18 are formed by performing plastic working simultaneously with a die and a punch (not shown) attached to the caulking processing apparatus 10 and having an uneven relationship, They are in close contact with each other, and the vertical wall surface 15a and the flange portion 16a, and consequently the panel 15 and the reinforcement 16 are temporarily fixed with the plurality of crimped embossed portions 17 and 18.

  At the same time, the caulking embossed portions 17 and 18 that are bulged and formed in advance on the vertical wall surface 15a and the flange portion 16a have a surface that is substantially perpendicular to the optical axis of the laser beam Lb. In this embodiment, the upper surfaces of the caulking embossed portions 17 and 18 are used as the shelf-like surfaces 17a and 18a, and the shelf-like surfaces 17a and 18a are overlapped with each other. 18a is set to be substantially perpendicular to the optical axis of the laser beam Lb.

  Therefore, at the stage where the caulking process is completed, the laser beam Lb is applied to the overlapped portion between the caulking embossed portions 17 and 18 and laser welding is performed by remote laser welding as shown in FIG. It is possible to reliably weld and join the force 16.

  In this case, since the panel 15 and the reinforcement 16 are temporarily fixed with the crimped embossed portions 17 and 18, the relative positioning accuracy or shape freezing property of both can be maintained by itself, and the panel 15 is subjected to laser welding. There is no need for any jigs to restrain them.

  In addition, the overlapped portion between the caulking embossed portions 17 and 18 is formed by molding them at the same time, so that the adhesion between them is excellent, and there is no gap in the overlapped portion between the caulked embossed portions 17 and 18. With this, good welding can be performed.

  The shape of the caulking embossed portions 17 and 18 is merely an example, and may be, for example, a cylindrical shape. In short, a laser beam is used so that laser welding is possible even at an irradiation angle of the laser beam Lb as shown in FIG. The shelf-like surfaces 17a and 18a that are substantially perpendicular to the optical axis of the light Lb need only be secured.

  Thus, according to the present embodiment, even if the irradiation direction of the laser beam Lb is substantially parallel to the vertical wall surface 15a of the panel 15 and the flange portion 16a on the reinforcement 16 side, the vertical wall surfaces thereof. Good laser welding can be performed using the 15a and the flange portion 16a as the welded surfaces.

Explanatory drawing which shows the outline of the remote laser welding method used for this invention. The principal part perspective view which shows specific embodiment of the laser welded joint which concerns on this invention. The expanded sectional view which follows the AA line of FIG. The expanded sectional view which shows the modification of FIG. The principal part perspective view before welding which shows another embodiment of this invention. The principal part perspective view which shows the structure of the welded joint after performing laser welding in the state of FIG. The expanded sectional view which follows the BB line of FIG.

Explanation of symbols

3, 4 ... Mirror 5 ... Panel (to-be-welded)
5a ... Vertical wall surface 6 ... Reinforce (workpiece)
6a ... Flange (vertical wall surface)
7, 8 ... Embossed part (projection part)
7a, 8a ... shelf-like surface 10 ... caulking device 15 ... panel (object to be welded)
15a ... Vertical wall surface 16 ... Reinforce (workpiece)
16a ... Flange (vertical wall surface)
17, 18 ... Caulking embossed part (projection part)
17a, 18a ... shelf surface Lb ... laser beam

Claims (7)

It is a welded joint structure in which laser welding is performed on the overlapping portion of the wall surfaces that are parallel to the irradiation direction of the laser beam or have a minute acute angle among the workpieces,
Protruding portions including a shelf-like surface that is substantially perpendicular to the direction of laser light irradiation in the overlapping portion between the wall surfaces are formed in advance,
A welded joint structure by laser welding, wherein laser welding is performed using the shelf-like surface of the projection as a laser beam irradiation surface.   The welded joint structure by laser welding according to claim 1, wherein the overlapping surfaces of the shelf-like surfaces are slidable in a direction in which the overlapping wall surfaces approach and separate from each other.   The welded joint structure by laser welding according to claim 1 or 2, wherein a plurality of protrusions are formed to bulge in the overlapping portion between the wall surfaces.   The welded joint structure by laser welding according to any one of claims 1 to 3, wherein relative positioning of the wall surfaces of the workpiece is performed by the protrusions. It is a method of performing laser welding on the overlapping portion of the wall surfaces that are parallel to the irradiation direction of the laser beam or have a minute acute angle among the workpieces,
Prior to laser welding, a protrusion including a shelf-like surface that is substantially perpendicular to the direction of laser light irradiation is preliminarily formed on the overlapping portion between the wall surfaces,
A laser welding method characterized in that laser welding is performed using the shelf-like surface of the projection as a laser light irradiation surface. A plurality of protrusions are set in the overlapping portion between the wall surfaces,
While the laser beam is reflected by at least two mirrors and laser beam is irradiated onto the shelf surface of the protrusion, welding is performed, while the angle of the mirror is changed to change the shelf of the protrusion that is the next welding position. 6. The laser welding method according to claim 5, wherein the laser welding method is a remote laser welding method in which a laser beam is instantaneously moved to a surface to perform next welding.   The laser welding method according to claim 6, wherein the protrusions are bulged and formed prior to laser welding so that the wall surfaces of the workpieces are temporarily fixed with the protrusions.

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