JP2000326078A - Welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely discharge a gas evaporating from a surface treatment material and to dispense with a need to specially use a low-melting point material by setting a welded place close to the end edge of a plate material and forcedly spreading the end edge part of the plate material, when fusing from one end of surface treated plate materials laminated in plural sheets and welding the plate materials. SOLUTION: Plate materials 5, 6 as a flange are sandwiched firmly by pressing members 11, 12 and forcedly spread at the end edge part of the plate materials 5, 6 by a spreading member 13, a clearance 14 is formed between both flanges. The flange 6 is elastically deformed by pushing the spread member 13, the other flange remains being straight. The clearance 14 is gradually enlarged, starting at the place of the pressing members 11, 12 down the right. The end edge part 15 of the flange is pushed with the spread member 13 and is protruded over the end edge part 16. The neighborhood of the end edge parts 15, 16 is irradiated with a welding laser beam 9, the place being an appropriate clearance for exhausting the gas evaporating from a surface treating material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION [0002] A metal plate material that has been subjected to surface treatment such as galvanization or coating of a synthetic resin material is welded by a laser beam or the like. In this case, a gap is set between the two plate materials in order to discharge the evaporated gas of the surface treatment material. The present invention belongs to the field of setting such a gap.

[0002]

2. Description of the Related Art The prior art will be described with reference to FIGS. FIG. 7 is a cross-sectional plan view showing a part of an automobile body made of a steel plate, and shows a part of a door frame 2 in which the door 1 fits. The door frame 2 corresponds to a pillar portion at the location shown in the figure, and the outer plate 3 and the inner plate 4 are joined by laser welding at their respective flanges 5 and 6.
Although not shown, the steel plates used for the inner and outer plates 3 and 4 are plated with a zinc-nickel alloy.

FIGS. 4 to 6 show enlarged portions of the flanges 5 and 6, and a gap 7 between the flanges 5 and 6 is exaggerated for easy understanding. When the laser beam 9 is irradiated, the flange 6 is initially heated and the heat causes the plating material to become an evaporating gas. At about the same time or immediately thereafter, the flange 6 is melted. The molten metal is scattered by the expansion of the vaporized gas of the plating material, and a blow hole is generated. In order to cope with such a phenomenon, the gap 7 is provided and the evaporative gas is discharged therefrom. The plate material here is a plated steel plate as described above. Generally, the plate thickness is 0.8 mm to 1.0 mm, and the gap 7 is 0.10 mm to 0.40 mm.
In order to secure such a gap, various measures as illustrated are employed.

That is, in the case of FIG. 6, a predetermined gap is secured by sandwiching the low melting point material 8 between the flanges 5 and 6. The material 8 is selected from those that melt at a temperature lower than the boiling point of the plating material. For example, a cellulose-based insert member is employed. Since the low melting point material 8 is already melted before evaporative gas is generated,
When the evaporating gas is generated, it is discharged to the outside while extruding the low melting point material 8, so that no gas pressure acts on the molten metal of the flanges 6 and 5. In the case of FIG. 5, the gap 6 is provided by bending the flange 6. Evaporated gas is
The paper is discharged through the gap 7 in a direction perpendicular to the plane of FIG. In the case of FIG. 4, an emboss 10 is provided on the flange 6, and a gap 7 is formed by the protrusion. Evaporated gas is
It is discharged from this gap 7.

[0005]

In the case shown in FIG. 6, a low-melting-point material is used for the purpose of providing the gap, which is disadvantageous in terms of cost. Further, since the low melting point material has a relatively low hardness, it cannot be said to be a preferable method for uniformly obtaining fine gaps. Next, in the case of FIG. 5, there is a problem that if the gap is too small, the gas is insufficiently discharged or the molten region is not uniform due to the variation in the press accuracy.
Further, if the gap is too large, there is a possibility that shortage may occur in terms of meltability even if gas is discharged. Further, in the case of FIG. 4, it is difficult to set the height of the emboss uniformly, and there is the same problem as in the case of FIG.

[0006]

SUMMARY OF THE INVENTION The above-mentioned problems arise in a method of melting one plate material and welding it to the other plate material, and the present invention solves these problems. It was invented to do so. In addition, since it is such a melting process, the types of welding employed in the present invention include laser welding, arc welding, plasma welding and the like.

According to a first aspect of the present invention, at least two surface-treated plate materials are overlapped, and one of the plate materials is melted to weld the two plate materials. This welding method is characterized by being near the edge, forcibly expanding the edge portions of both plate members to form a gap for gas discharge. Therefore, the evaporated gas of the surface treatment material is discharged to the outside from the gap formed compulsorily.

A second aspect of the present invention is the welding method according to the first aspect, wherein both the plate members are flanges of a sheet metal part, and the edges thereof are forcibly expanded. Therefore, the evaporated gas moves toward the edge of the flange and is discharged to the outside.

According to a third aspect of the present invention, there is provided a welding method according to the second aspect, wherein one of the flange edges protrudes from the other, and the protruding portion is forcibly expanded. Therefore, the evaporative gas is discharged from the gap formed by pushing out the protruding portion.

[0010]

1 to 3 show the case where the present invention is applied to the vehicle body structure shown in FIG. 7, and the present invention will be described in detail below. FIG. 1 is a longitudinal sectional side view principally showing the present invention, and shows a case of laser welding. The plate material here is the above-mentioned flanges 5 and 6, which are strongly sandwiched by the pressing members 11 and 12. The two flanges 5 and 6 are forcibly expanded at their end portions by the expanding member 13, whereby a gap 14 is formed between the two flanges. Due to the pressing of the expanding member 13, the flange 6 undergoes elastic deformation as shown, while the other flange 5 remains straight. The gap 14 is formed by the pressing member 1
It becomes gradually larger from the points 1 and 12 to the right. Reference numerals 15 and 16 denote end portions of each flange.
It is in a state protruding beyond 5. Laser beam 9
Is irradiated near the edge portions 15 and 16, and the portion is a gap appropriate for discharging the evaporated gas of the plating material.

Factors that determine the form of the gap 14 include the distance LW from the pressing members 11 and 12 to the edge 16, the extension length LH of the expanding member 13, the bent shape of the flange 6, and the like.

As an example for putting the principle shown in FIG. 1 to practical use, there is a welding apparatus 21 as shown in FIG. The inner plate 3 and the outer plate 4 are fixed by jigs 17 and 18 in a state where both flanges 5 and 6 are overlapped. The welding device 21 is operated by a robot mechanism, and a support arm 20 is connected to a U-shaped frame 19 which is a basic member of the welding device 21. The support arm 20 is an end arm of a normal 6-axis robot, and moves the entire frame 19 in the longitudinal direction of the flanges 5 and 6 (perpendicular to the plane of FIG. 2), and further according to the shape of the flange. The movement trajectory bent is given to the frame 19.

The flanges 5 and 6 are sandwiched between pressure rollers 22 and 23 corresponding to the pressure members 11 and 12 described above, and the pressing force of the rollers 22 and 23 is of various types such as hydraulic pressure and air pressure. However, in this case, a compression coil spring is used. The shafts 26 and 27 are attached to the support frames 24 and 25, and the rollers 22 and 23
Is supported. Guide rods 28 and 29 are connected to the support frames 24 and 25, and are fitted in guide cylinders 30 and 31 fixed to the frame 19 so as to be able to advance and retreat. The above-described compression coil springs 32, 33
The flanges 5 and 6 are installed between the frame 5 and the frame 19 and pressurized by the resilience.

An end roller 16 is configured to be spread by an expanding roller 34 corresponding to the expanding member 13 described above. The shaft 35 of the expanding roller 34 is bridged over a support frame 36, and the support frame 36 is fixed to a column 37 that is firmly fixed to the frame 19. The dimensions of the pillars 37, the support frame 36, the diameters of the expanding rollers 34, and the like are selected so that the above-described advance length LH is set to a predetermined value. The mounting position of the laser focusing unit 38 is determined so that the laser focusing unit 38 is fixed to the frame 19 and the laser beam 9 emitted from the laser focusing unit 38 reaches an appropriate portion of the flange. Reference numeral 39 denotes an optical fiber. 2 is not shown, the shafts 26, 2
The laser beams 7, 35, the laser beam 9, and the like are positioned on or near one virtual plane in the vertical direction.

In the state shown in FIG. 2, when the laser beam 9 is irradiated while the welding device 21 is moved by the robot mechanism, the flanges 5 and 6 are brought into close contact with the pressure rollers 22 and 23, and at the same time, are spread by the expanding roller 34. A gap 14 is formed, and the vaporized gas of the plating material is discharged from this gap. Such an operation is performed continuously as the welding device 21 moves.

The embodiment shown in FIG. 3 is a modification of the embodiment shown in FIG. 2. In this embodiment, the lengths of the edge portions 15 and 16 of the flanges are set to be the same, and the expanding roller 40 is operated from the side. A cylindrical roller 40 is provided with an expanding rib 41 at the center in the circumferential direction. When a pointed point like an abacus is pushed between the flanges 5 and 6, a gap 14 is formed. This modification is also provided with a support frame 42, a shaft 43 and a guide rod 44 similar to those described above.

An example of the experiment is as follows. The plate material used is a 1.0 mm-thick zinc-nickel alloy-plated steel plate.
23 mm. Therefore, LW of FIG. 1 is 8.0 mm, LH
Was set to 0.3 mm. Laser welding machine has output of 2.8Kw
The laser type is YAG laser and the moving speed is 1.3 m / min. It is. Although not shown, argon gas was used as a shielding gas. As a result, no abnormality due to the occurrence of blowholes or the behavior of evaporative gas was observed in the welded portion.

In the above description, a steel sheet plated with zinc / nickel alloy is exemplified. However, as another surface-treated steel sheet, the present invention can be applied to a colored steel sheet baked and coated with melamine resin or acrylic resin. Can be applied. In this case, the coating film becomes gaseous and diverges,
It is discharged as described above. Furthermore, the present invention can be applied to various types of steel plates such as a galvanized steel plate, a turn-plated steel plate, and a hot-dip aluminum-plated chromium alloy steel plate. The present invention can be applied to a zinc-plated aluminum plate or a surface-treated titanium plate as a plate other than a steel plate.

Although not described in the claims, the following matters can be described in the claims. That is, by setting the relationship between LW and LH in FIG. 1, a uniform gap can be accurately secured. Also,
By making the pressing member and the expanding member a roller structure,
Continuous welding becomes possible. Other than these, matters that can be described as claims can be found in the embodiments.

[0020]

According to the present invention, welding is performed near the edge of the sheet material, and the edge is forcibly expanded to provide a gap between the two sheet materials for welding. The gap has the expected size depending on the degree of expansion, and uniform gap management can be easily realized at all times, so that the evaporative gas of the surface treatment material can be accurately discharged. Further, it is possible to avoid special preparation of the low melting point material as in the prior art, which is advantageous in terms of cost and work.

Since the gap between the two plate members is formed by expanding the edge side of the plate member, the gap is gradually increased. Therefore, if a gap having a size suitable for the welding conditions at that time is selected, optimum welding quality can be obtained. Since the gap is wedge-shaped in this way, the evaporative gas is discharged toward the wider gap, so that the gas can be smoothly and reliably discharged.

When the method of the present invention is applied to a flange portion of a sheet metal part, a uniform gap can be secured along the elongated flange, so that the welding line can be formed straight or beautifully along a predetermined curve, and the welding strength can be improved. It is also advantageous in terms of.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional side view showing the present invention in principle.

FIG. 2 is a side view of a welding device that implements the principle of FIG. 1;

FIG. 3 is a side view partially showing another welding device.

FIG. 4 is a longitudinal sectional side view of a conventional flange portion.

FIG. 5 is a longitudinal sectional side view of another conventional flange portion.

FIG. 6 is a longitudinal sectional side view of a flange portion of still another prior art.

FIG. 7 is a cross-sectional plan view of a portion of the door frame.

[Explanation of symbols]

 5, 6 plate material, flange 15, 16 edge, edge 14 gap

Claims (3)

[Claims] 1. A type in which at least two surface-treated plate members are overlapped, and one of the plate members is melted to weld the two plate members, and the welding portion is located near an edge of the plate member. A welding method characterized by forming a gap for gas discharge by forcibly expanding the edges of both plate members. 2. The welding method according to claim 1, wherein the two sheet materials are flanges of a sheet metal part, and the edges thereof are forcibly expanded. 3. The welding method according to claim 2, wherein one of the flange edges protrudes beyond the other, and the protruding portion is forcibly expanded.