JP2001129676A - Laser welding jig - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a jig which can keep a required micro gap stably reliably between the panels to be welded for lap welding of a steel sheet panel by laser beam at welding operation over a whole weld line without concerning a shape or size. SOLUTION: A press roller 1 comes in rolling contact with a panel 9 at a place 8a near to a weld 7 and the roller, links with the laser beam A which irradiates from a welding machine head 1a, moves almost parallel to the weld line shown in Figure 2. A press roller 2 and 3 come in rolling contact with a panel 10 and 9 at a place 8b and 8, respectively, and are almost parallel to the weld line. The diameter of the press roller 2 is designed as smaller size than that of the roller 3 in order to ensure a distance comprising the total thickness of the plate 9 and 10, and a required panel gap 6 between the press roller 2 and 3, thereby ensuring the gap 6 to prevent flaws at the weld.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to a technical field related to a jig for performing an operation of lap welding two metal plates with a laser.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a conventional technique for welding two metal plates by laser lap welding. An operation method in which thin steel plate panels 9 and 10 held substantially horizontally are overlapped at a welding portion 26, and a laser beam is radiated from a laser welding head 22 to perform welding connection. In many cases, both surfaces of the steel plate panels 9 and 10 are provided with a rust-proof layer made of a low melting point material such as zinc. In such a case, maintaining a very small panel gap 24 during welding is an indispensable operating condition for ensuring the soundness of the welded portion. At a high welding temperature of the steel plate panels 9 and 10 as the welding base material, the low melting point material such as zinc instantaneously boils and becomes explosively radiated as metal fume. If it does not escape outside the weld, it will easily enter the base metal weld and cause defects in the weld. However, if the panel gap 24 is unnecessarily large, the metal fumes can be escaped, but the adhesion between the panels 9 and 10, which are the base materials, becomes poor, and there is a possibility that incomplete welding may occur. In order to avoid such a problem, the panel gap 24 is extremely small compared to the plate thickness in consideration of a combination of laser beam energy, plate thickness, material and the like in order to satisfy both the metal fume discharging performance and the welding performance. Must be held to value.

In the prior art shown in FIG. 6, a welding head 22 and a press roller 23 are mounted on an articulated robot 21, and a laser welding operation is performed while holding a lap welding portion 26 with a press roller 23. The follower damper 25 is for absorbing the movement in the thickness direction of the pressing roller 23 that rolls along the three-dimensional shape change of the panels 9 and 10. In this prior art, when the panels 9 and 10 have a large area such as a floor or a roof of a vehicle, the arm length of the articulated robot 21 becomes large, so that the lap welding portion 2 is formed.
6 makes it difficult to control the minute position of the press roller 23 in the plate thickness direction, and presses the press roller 23 from below the panel 10.
Therefore, the position of the panel 10 cannot be actively controlled to prevent the panel gap 24 for sound welding from being stably maintained.

As another example of the prior art, there is a laser seam welding machine disclosed in Japanese Patent Application Laid-Open Publication No. 58-47590. In this method, a lap welded portion of two panels as a welding base material is formed from both sides. This is a method of closely contacting with a pressing roller without a gap, and it is not possible to create a panel gap. Therefore, it is not suitable for welding a panel protected by a low melting point material.

In the welding apparatus disclosed in Japanese Patent Application Laid-Open No. 61-135494, one of the panels is lifted by an electromagnet to provide a minute gap between two panels to be welded. When the panel to be welded is a flat plate having a simple shape, the minute gap can be accurately maintained over the entire length of the welding line. However, in practice, the panel to be welded is designed and formed in a three-dimensional shape, and is locally formed. Has an irregular three-dimensional shape as a molding error. Since these dimensions are orders of magnitude larger than the required minute gap between the panels to be welded, simply raising one of the panels to be welded by a certain amount as in this example will ensure sound welding over the entire welding line. Maintaining small gaps is very difficult.

In the method of welding a galvanized steel sheet disclosed in Japanese Unexamined Patent Publication No. Hei 7-32180, only one of the panels is preliminarily melted in parallel with the lap welding line and the end of the panel is melted by the shrinkage effect of the welded portion. In this method, if the panel to be welded is a simple flat plate, the minute gap is created exactly over the entire length of the welding line. However, in practice, the panel to be welded is designed and formed in a three-dimensional shape, and there is an irregular three-dimensional shape as a forming error locally. In such a three-dimensionally formed part, the effect of shrinking the melted part created in advance cannot create uniform minute gaps. Also, the energy consumption of laser beam welding increases.

In the laser welding of a lap joint disclosed in Japanese Patent Laid-Open Publication No. 7-16776, there is provided a method of adjusting a laser beam irradiation angle and a focal position so that a welding amount largely spreads on a lap joint surface. Therefore, it is not suitable for welding materials that require a minute gap such as a zinc-coated steel plate.

[0008]

As described above, in order to secure defect-free welding in laser lap welding of thin steel sheet panels such as zinc-painted panels, regardless of the shape and dimensions of the panels to be welded, It is necessary to stably maintain a small gap between the panels over the entire length of the weld line.

Accordingly, the present invention provides a method of lap welding thin steel sheets such as zinc-coated steel sheets having a large area in a three-dimensional shape with a laser beam, regardless of the shape and dimensions of the panels to be welded. An object of the present invention is to provide a jig for stably and surely maintaining a required minute gap during welding over the entire length.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an apparatus for performing lap welding of two metal plates with a laser. And three rollers that roll with the laser welding head substantially parallel to the line, wherein a first roller and a second roller of the three rollers are one of the metal plates.
And only the third roller of the three rollers has a smaller diameter than the second roller and is arranged coaxially with the second roller. ,
The third roller and the first roller overlap both of the two metal plates in the plate thickness direction and simultaneously pinch the two metal plates, and the two metal plates required for the lap welding work in the plate thickness direction. By maintaining the relative position, a small gap between the two metal plates is stably secured during welding over the entire length of the welding line at a portion of the welding line where the two metal plates are overlap-welded. The purpose of this is to create a laser welding jig.

[0011]

FIG. 1 is an overall perspective view of a jig according to an embodiment of the present invention. The holding roller 1 and the welding head 1a are mounted on the welding head slider 15. The holding rollers 2 and 3 are mounted on a holding roller slider 16. Welding head slider 15 is driven screw 1
It is moved in the direction D by one rotation. The press roller slider 16 moves in the E direction by the rotation of the drive screw 13. Guides 12 and 14 are welding head sliders 15
And a sliding guide for stabilizing the position of the press roller slider 16. The driven screw 11 and the driving screw 13 are a driven pulley 17, a driving pulley 18, and a belt 19.
, So that the relative positions of the welding head slider 15 and the presser roller slider 16 can be moved in the D and E directions synchronously without change. The frame 20 stably holds the parts with a certain rigidity.

FIG. 2 is a three-dimensional perspective view of the structure near the pressing rollers 1, 2, and 3 in FIG. The press roller 1 is in rolling contact with the portion to be welded on the panel 9 near the welding line 1b, is fixed to the welding head slider 15 together with the welding head 1a, and moves substantially parallel to the welding line 1b. The pressing roller 1 is pressed in the thickness direction of the panel 9 and moves in the B direction along the three-dimensional shape of the panel 9 by the operation of the follower damper 1d, so that the pressing roller 1 comes into rolling contact with the panel 9. The welding is completed by irradiating the laser beam A to the welding line 1b. The press rollers 2 and 3 are in rolling contact with the panel 10 and the panel 9 in the vicinity of the weld line 1b from the opposite side of the press roller 1 substantially in parallel with the weld line 1b. The pressing rollers 2 and 3 are coaxially arranged, move in the direction C along the three-dimensional shape of the panels 9 and 10 by the operation of the follower damper 2a, and come into rolling contact with the panel 9.

FIG. 3 is an overall front view of the jig according to the embodiment of the present invention. The welded panels 9 and 10 are the welding head 1
The welding position is secured by being held between the holding roller 1 and the holding rollers 2 and 3 below the position a. FIG. 4 shows an overall side view of the jig according to the embodiment of the present invention. The lap welds of the panels 9 and 10 are located below the welding head 1a. The welding head slider 15 is moved in the direction D as shown in FIG. 3 by the driven screw 11 shown in FIG. The pressing roller slider 16 is moved in the direction E by the driving screw 13 shown in FIG. The guides 12 and 14 are sliding guides for stabilizing the positions of the welding head slider 15 and the press roller slider 16. Since the driven screw 11 and the driving screw 13 rotate synchronously as described with reference to FIG.
Welding head slider 15 and presser roller slider 1
6 can be moved in the D and E directions synchronously without change.

FIG. 5 is an enlarged detailed side view of a portion F in FIG. The press roller 1 is in rolling contact with the welded portion 7 of the panel 9 near the welded portion 7 at 8a, and together with the laser beam A emitted from the welding head 1a, the welding line 1 shown in FIG.
It moves substantially parallel to b. The pressing roller 1 is pressed in the thickness direction of the panel 9 and moves in the B direction along the three-dimensional shape of the panel 9 by the operation of the follower damper arm 4 connected to the follower damper 1d, thereby rolling contact with the panel 9. Pressing rollers 2 and 3 are respectively attached to panels 10 and 9 in close contact with welding line 1b in the vicinity of welding line 1b shown in FIG.
Rolling contact at b and 8. The pressing rollers 2 and 3 are disposed coaxially, and each of the panels 10 and 10 is driven by an operation of a follower damper arm 5 connected to a follower damper 2a.
Panel 9 moves in the C direction along the three-dimensional shape of FIGS.
And 9 in rolling contact. The diameter of the press roller 2 is smaller than that of the press roller 3, and the press roller 1
And the press roller 2 to secure a distance obtained by adding a required panel gap 6 to the total thickness of the panels 9 and 10.
Therefore, a panel gap 6 for preventing defects in the welded portion is secured. As shown in FIGS. 1 to 4, the holding roller 1 is mounted on the welding head slider 15, the holding rollers 2 and 3 are mounted on the holding roller slider 16, and move in synchronism with each other.
2 and 3, the relative positional relationship between the overlapped portions of panels 9 and 10 and press rollers 1, 2, and 3 can be determined even if the overlapped portions have a three-dimensional shape as shown in FIG.
Does not change over the entire length of the welding line 1b. Therefore, it is possible to secure a panel gap 6 essential for preventing lap welding defects over the entire length of the welding line 1b shown in FIG.

[0015]

As described above, 1) the three pressing rollers securely pinch the two panels to be welded over the entire length of the welding line, so that the panel gap which is indispensable for preventing defects in lap welding can be reduced. Can be secured. 2) By changing the diameter of the holding roller to be used, a required panel gap can be set according to various plate thicknesses and welding conditions.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a jig according to an embodiment of the present invention.

FIG. 2 is a three-dimensional perspective view of a structure near a pressing roller 1, 2, and 3 in FIG.

FIG. 3 is an overall front view of the jig according to the embodiment of the present invention.

FIG. 4 is an overall side view of the jig according to the embodiment of the present invention.

FIG. 5 is an enlarged detailed side view of a portion F in FIG. 4;

FIG. 6 shows an example of a conventional technique for welding two metal plates by laser lap welding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Holding roller 1a Welding head 1b Welding line 1c Welding head wire 1d Follower damper 2 Holding roller 2a Follower damper 3 Holding roller 4 Follower damper arm 5 Follower damper arm 6 Panel gap 7 Laser welding part 8 Adhesive part 8a Adhesive part 8b Adhesive part 9 Panel to be welded 10 Panel to be welded 11 Driven screw 12 Guide 13 Drive screw 14 Guide 15 Welding head slider 16 Holding roller slider 17 Driven pulley 18 Drive pulley 19 Synchronous drive belt 20 Frame

Claims (1)

[Claims] An apparatus for performing lap welding of two metal plates with a laser, wherein the three metal plates roll together with a laser welding head near a welding line to be lap welded and substantially parallel to the welding line. Of the three rollers, the first roller and the second roller of the three rollers tightly pinch only one of the metal plates from both sides in the thickness direction, and among the three rollers A third roller having a smaller diameter than the second roller and disposed coaxially with the second roller, wherein the third roller and the first roller are provided on both of the two metal plates; Are stacked in the thickness direction and pinched simultaneously.
By maintaining the relative positions in the thickness direction of the two metal plates required for the lap welding operation, a minute distance between the two metal plates at the welding line where the two metal plates are lap welded is maintained. A jig for laser welding, wherein a gap is stably secured during welding over the entire length of the welding line.