JPH0825068A - Welding method for laminated structure, laser welding method and working table device - Google Patents

Abstract

PURPOSE:To provide a laser welding method and a working table device by which an outside sheet panel and a reinforcing member can be welded speedily and with a high quality, and the adhesion of two plate-shape members can be improved without using a special jig. CONSTITUTION:After placing a tabular outside sheet panel 1 and a reinforcing member 2 with a rib 2b and a joining part 2a formed as one body on a working table 10 and being allowed to adhere, laser welding is performed by irradiating them with a laser beam from the reinforcing member 2 side. Consequently, a rolling stock body structure with the outside sheet panel 1 and the reinforcing member 2 joined, is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding method for a laminated structure such as a vehicle structure including an outer panel and a reinforcing member.
The present invention also relates to a laser welding method in which two plate-shaped members are brought into close contact with each other and welded by laser beam irradiation. The present invention also relates to a processing table device suitably used for these methods.

[0002]

2. Description of the Related Art Conventionally, a vehicle assembly used for a railway vehicle or the like is assembled by welding an outer panel and a reinforcing member integrally formed with ribs and joints (Japanese Patent Laid-Open No. 126659/1992). Issue). As an example of the welding method, as shown in FIG. 8, after the outer panel 1 and the reinforcing member 2 are brought into close contact with each other, the joint 2a between the outer panel 1 and the reinforcing member 2 is sandwiched between the two electrodes 3. Resistance spot welding is generally used in which Joule heat is generated at the joint between the outer panel and the reinforcing member by applying a large current to form the molten pool 4. In this welding method, the outer panel 1
A large number of welding spots 5 are formed on the outer surface 1a and the joint portion 2a of the reinforcing member 2.

[0003]

However, in the conventional resistance spot welding, indentations due to electrode pressing and discoloration due to high temperature oxidation are likely to remain on the outer surface (decorative surface) of the outer panel. In particular, in the case of stainless steel vehicles that are used unpainted, in order to remove the indentation and discoloration of the outer panel due to product quality, repair work after welding and polishing / cleaning work are indispensable, which increases manufacturing costs. It is a cause.

Further, since resistance spot welding is spot welding, a large number of spot weldings are required to secure the joint strength between members. Therefore, the number of movements and movement strokes of the electrode increase, the time required for welding increases, and the position control becomes complicated.

On the other hand, regarding the superposition of members, in the conventional resistance spot welding, two electrodes facing each other mechanically press each member, so that sufficient adhesion is achieved during welding. However, laser lap welding used in fields other than railway vehicle structures requires non-contact welding with a laser beam, and thus requires a separate holding jig for bringing the two members into close contact with each other. Further, the outer panel and the reinforcing member that form the vehicle body structure have a large planar projected area of, for example, width 1 m × length 2 m, and in particular, the reinforcing member is complicated because the rib and the joint are formed. It is difficult to evenly press the reinforcing member against the outer panel with such a holding jig.

Further, when the member is distorted such as twisted, if the lap welding is performed as it is, the distorted state will result. However, in the conventional resistance spot welding, only the member is positioned on the working table, and no jig for distortion correction is used. Further, also in the laser lap welding, a jig is used to bring the members placed on the processing table into close contact with each other, but a large number of large jigs are required to correct the member distortion. Further, when a large-sized holding jig is used, there is a high possibility that it will interfere with a welding nozzle that generates a laser beam or that the laser beam will be blocked, and control for avoiding interference will be complicated.

An object of the present invention is to provide a method for welding a laminated structure capable of welding an outer panel and a reinforcing member at high speed and avoiding electrode indentations and high-temperature discoloration.

Another object of the present invention is to provide a laser welding method capable of improving the adhesion between two plate-shaped members without using a special jig and improving the welding accuracy and quality. .

Another object of the present invention is to provide a working table device which can improve the welding accuracy and quality of two plate members.

[0010]

SUMMARY OF THE INVENTION The present invention is a method for welding a laminated structure comprising an outer panel and a reinforcing member integrally formed with ribs and joints, the method comprising the steps of: A laser beam is irradiated from the reinforcing member side to the portion in close contact with the plate panel to heat and melt the region from the surface of the reinforcing member to the inside of the outer panel, thereby joining the outer panel and the reinforcing member. This is a method for welding a laminated structure, which is characterized in that

Further, according to the present invention, two plate-shaped members each having a recessed portion formed in at least one of them are brought into close contact with each other to form a sealed space in the recessed portion, and the pressure in the sealed space is set to be less than atmospheric pressure. The pressure difference reduces the contact force of the plate members by increasing the pressure difference, and the portion where the plate members are in close contact with each other is irradiated with a laser beam from one plate member side, and the surface of one plate member moves to the other plate. The laser welding method is characterized in that a region up to the inside of the strip-shaped member is heated and melted and joined.

Further, the present invention is characterized in that the two plate-shaped members are brought into close contact with each other and then temporarily fixed by resistance spot welding.

Further, according to the present invention, the two plate-shaped members are placed on a processing table having a large number of suction holes, and the gap between the other plate-shaped member and the processing table is sucked from the suction holes,
The other plate-shaped member is closely attached to the processing table.

Further, according to the present invention, the processing table is cooled,
It is characterized by absorbing the processing heat of the plate member.

Further, according to the present invention, a processing table having a large number of suction holes formed on a work mounting surface, a ventilation pipe line communicating with each suction hole, and an exhaust means for exhausting the ventilation pipe line,
A processing table device, comprising: a cooling pipe line for circulating a cooling medium for cooling the processing table.

[0016]

According to the present invention, by irradiating the laser beam from the reinforcing member side to heat and melt the region from the surface of the reinforcing member to the inside of the outer panel, welding beads and indentations are formed on the outer surface of the outer panel. High quality welding can be achieved because there is no appearance defect such as discoloration. Moreover, since the processing head that generates the laser beam during welding moves without contact with the reinforcing member, high-speed movement is possible. Furthermore, since the linear bonding becomes possible by moving the processing head while irradiating the laser beam, it is possible to improve the bonding strength by increasing the bonding area.

Further, according to the invention, two plate-shaped members each having a recessed portion formed in at least one of them, for example, an outer panel of a vehicle structure and a reinforcing member are brought into close contact with each other to form a sealed space in the recessed portion. However, the pressure in the sealed space can be reduced below atmospheric pressure by, for example, vacuum suction, and the pressure difference can increase the adhesion of the plate-shaped member. Furthermore, since a special pressing jig is not required, the degree of freedom of traveling of the processing head is increased and quick position control is possible. Further, since the region from the surface of one plate member to the inside of the other plate member is heated and melted by the irradiation of the laser beam, the appearance defect does not appear on the outer surface of the other plate member.

Further, even if the plate-shaped member is so distorted that suction in the sealed space may not be performed completely, after the two plate-shaped members are brought into close contact with each other, resistance is applied to predetermined 5 to 10 places. By performing temporary fixing by spot welding, suction of the sealed space can be reliably performed.

Further, the two plate-shaped members are placed on a processing table having a large number of suction holes, and the gap between the other plate-shaped member and the processing table is sucked through the suction holes to obtain the other plate. Since the plate-shaped member is corrected along the placement surface of the processing table by bringing the plate-shaped member into close contact with the processing table,
Welding accuracy is greatly improved. Furthermore, since the processing heat of the plate-shaped member is conducted to the processing table and the temperature rise is suppressed,
Discoloration due to high temperature oxidation can be prevented. Further, by cooling the processing table, the heat dissipation efficiency of the plate member is significantly improved.

Further, according to the present invention, a large number of suction holes are formed on the work mounting surface, a ventilation pipe line is provided to connect the suction holes, and the ventilation pipe line is exhausted by an exhaust means such as a vacuum pump. As a result, the member on the work placement surface is brought into close contact with the processing table, so that the member can be fixed uniformly and surely without using a special jig. Furthermore, by circulating a cooling medium that cools the processing table, the processing heat of the member is efficiently dissipated and, for example, deterioration or discoloration due to high temperature oxidation can be suppressed.

[0021]

FIG. 1 is a perspective view for explaining an embodiment of the present invention. The flat plate-shaped outer panel 1 and the reinforcing member 2 integrally formed with the ribs 2b and the joints 2a are placed on the processing table 10 and brought into close contact with each other, and then a laser beam is emitted from the reinforcing member 2 side to emit a laser beam. By performing welding, a railway vehicle structure in which the outer panel 1 and the reinforcing member 2 are joined can be obtained.

FIG. 2 (a) is a partial plan view of the railway vehicle body structure shown in FIG. 1, and FIG. 2 (b) is a partial sectional view of a welding line. The reinforcing member 2 is formed by pressing a flat plate such as a steel plate into a plurality of corner-round trapezoidal recesses, and the bottom surface of the recess has a joining portion 2 as necessary to reduce weight.
It is cut off leaving a. The joint portion 2a and the flat portion 2c of the reinforcing member 2 are ribs 2b formed of inclined surfaces or vertical surfaces.
The ribs 2b enhance the rigidity of the railway vehicle body structure.

When a laser beam 7 having a large output is focused and irradiated from the side of the reinforcing member 2 to the portion where the joint portion 2a of the reinforcing member 2 and the outer panel 1 are in close contact with each other in this way, FIG.
As shown in, the area from the surface of the reinforcing member 2 to the inside of the outer panel 1 is heated and melted to form a wedge-shaped molten pool 6. Therefore, when a processing head that generates the laser beam 7 is mounted on a numerical control processing machine or the like and the laser beam 7 is continuously moved along the joint 2a, as shown in FIG. The welding line 8 can be formed. In this way, the joining area is significantly larger than that of spot welding, and the joining strength is greatly improved. Further, since the processing head can be continuously moved, the welding speed can be increased. At this time, the length of the welding line 8 and the welding path are determined in consideration of the required joint strength and the shape of the reinforcing member 2. Further, by controlling the output of the laser beam 7 and the traveling speed so that the molten pool 6 does not reach the outer surface 1a of the outer panel 1, it is possible to prevent deterioration and discoloration due to high temperature oxidation. Further, the outer surface 1a of the outer panel 1
The outer panel 1 by bringing the table into close contact with the processing table 10.
Since the processing heat of 1 is radiated to the processing table 10, the temperature rise is suppressed. Therefore, it is preferable that the processing table 10 is formed of a material having excellent heat conduction, for example, copper or a copper alloy, and the cooling efficiency of the processing table 10 is improved by cooling the processing table 10 with water.

FIG. 3 is a perspective view showing another embodiment of the present invention, and FIG. 4 is a sectional view taken along the line A1-A1 in FIG. Place the flat panel panel 1 on the processing table 10,
When the reinforcing member 2 integrally formed with the rib 2b and the joint portion 2a is placed, the joint portion 2a and the outer panel 1 are brought into close contact with each other, and the flat portion 2c becomes a recessed portion to form the sealing space 9
Is formed. Exhaust pipe 20 communicating with this sealed space 9
However, it is detachably attached to the outer peripheral surface of the reinforcing member 2.
It should be noted that the reinforcing member 2 of FIG. 3 is different from that of FIG. 1 in that the bottom surface of the rounded trapezoidal recess forms the joint portion 2a as it is.

Next, when the pressure in the sealed space 9 is lowered below the atmospheric pressure by vacuum suction from the exhaust pipe 20, a differential pressure from the atmospheric pressure is applied to the entire reinforcing member 2 as shown in FIG. do it,
The adhesive force between the reinforcing member 2 and the outer panel 1 increases. Before vacuum suction, resistance spot welding is preferably used to temporarily fix the reinforcing member 2 around the periphery and in the center at about 5 to 10 places, thereby sealing even if each member is distorted. Leakage in the space 9 is reduced, and the suction operation is ensured.

Next, the joining portion 2a of the reinforcing member 2 is irradiated with a laser beam from the reinforcing member 2 side, and the region from the surface of the reinforcing member 2 to the inside of the outer panel 1 is heated and melted and the welding line 8 is formed. To form. When all the welding is completed, the exhaust pipe 20 is removed. In this way, a railway vehicle structure in which the outer panel 1 and the reinforcing member 2 are reliably joined is obtained.

FIG. 5 is a perspective view showing an embodiment of the processing table device according to the present invention. FIG. 6 is a cross-sectional view showing the configuration of the processing table device of FIG. Processing table 10
A large number of suction holes 11 are formed on the workpiece mounting surface 10 a, and a ventilation pipe line 12 that connects the suction holes 11 is formed inside the processing table 10. The ventilation conduit 12 is connected to the exhaust pump 14.

On the work mounting surface 10a of the processing table 10, the outer panel 1 and the reinforcing member 2 shown in FIG. 3 are mounted, and the exhaust pipe 20 communicating with the sealed space 9 is mounted. The exhaust pipe 20 is connected to the exhaust pump 14 via the connector 13.

On the other hand, a cooling pipe 30 for circulating a cooling medium L such as water is formed inside the processing table 10 to cool the processing table 10. Cooling line 30
Is connected to a pipe 32 via a connector 31, and is further connected to a fluid pump 33 for circulating the cooling medium L and a storage tank 34 for storing the cooling medium L and lowering the temperature.

After placing the outer panel 1 and the reinforcing member 2 on the work placing surface 10a, the exhaust pump 14 is operated to make a gap between the outer panel 1 and the processing table 10 through the suction hole 11. When vacuum suction is performed, the outer panel 1 is brought into close contact with the work placement surface 10a due to the pressure difference from the atmospheric pressure. Since the work mounting surface 10a forms a reference surface having high flatness, even if the outer panel 1 is twisted, the work mounting surface 10a is corrected along the work mounting surface 10a.

On the other hand, when the sealing space 9 is also vacuum-sucked through the exhaust pipe 20, the adhesive force between the outer panel 1 and the reinforcing member 2 increases due to the pressure difference from the atmospheric pressure. Thus, without using a special holding jig, the outer panel 1 and the reinforcing member 2
Are reliably brought into close contact with each other along the work placement surface 10a.

Next, when the laser beam is applied to the joint portion 2a of the reinforcing member 2 while moving from the reinforcing member 2 side,
A region from the surface of the reinforcing member 2 to the inside of the outer panel 1 is heated and melted, and the two are securely joined. Since the outer surface 1a of the outer panel 1 is in close contact with the working table 10, the working heat of the outer panel 1 is efficiently radiated to the working table 10. Further, by circulating the cooling medium L in the cooling pipe 30, the processing table 10 made of copper or the like is cooled, and the processing heat of the outer panel 1 can be efficiently removed. In this way, it is possible to obtain a railway vehicle structure that does not have a discoloration or a defect such as a flaw.

FIG. 7 is a graph showing the results of a tensile shear load test of laser welding. Test condition is thickness 0.8m
m and 1.2 mm 2 stainless steel plates (SUS30
4) distance 0mm (perfect contact), 0.1mm, 0.2m
m and 0.3 mm respectively, the laser beam with an output of 2.5 kW was moved at a welding speed of 6.5 m / min to carry out welding, and then a tensile shear load was applied. It is a measurement of the load at the time of rupture.

Then, when the lap gap is plotted on the horizontal axis and the tensile shear load is plotted on the ordinate, the steel plates were completely adhered to each other, that is, 942, 821 in which laser welding was performed with a lap gap of 0 mm. The maximum tensile shear load of 843 (kgf) is shown. The tensile shear load tends to decrease as the lap gap increases.
When the overlapping gap becomes 0.3 mm, 108, 153, 16
It rapidly drops to a value of (kgf). As described above, since laser welding heats and melts in a non-contact manner, sufficient bonding strength cannot be achieved if the gap between the members becomes large. However, if the suction holding according to the present invention is used, the gap between the members is almost 0 mm.
Can be held at.

Further, in the above description, the outer panel 1 and the reinforcing member 2 constituting the railway vehicle body structure as the members to be welded.
However, if two or more plate-shaped members each having a recessed portion formed in one or both of them, the sealing space is formed by the close contact, so that suction and holding can be performed.

[0036]

As described above in detail, according to the present invention, it is possible to realize high-quality welding in which the outer surface of the outer panel does not show a defective external appearance and the joint strength is improved. Further, the adhesion force between the members to be welded can be improved and the adhesion force with the processing table is improved without preparing a special jig, so that reliable welding can be performed. Further, since the member to be welded is brought into close contact with the processing table to remove the heat generated during welding, it is possible to suppress alteration or discoloration due to, for example, high temperature oxidation.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating an embodiment of the present invention.

2 (a) is a partial plan view of the railway vehicle body structure shown in FIG. 1, and FIG. 2 (b) is a partial cross-sectional view of a welding line.

FIG. 3 is a perspective view showing another embodiment of the present invention.

4 is a cross-sectional view taken along the line A1-A1 in FIG.

FIG. 5 is a perspective view showing an embodiment of a processing table device according to the present invention.

6 is a cross-sectional view showing the configuration of the processing table device of FIG.

FIG. 7 is a graph showing the results of a tensile shear load test of laser welding.

FIG. 8 (a) is a partial plan view of a conventional railway vehicle body structure, and FIG. 8 (b) is a partial sectional view of a welding spot.

[Explanation of symbols]

 1 outer panel 2 reinforcing member 2a joint part 2b rib 2c flat part 6 welding pool 7 laser beam 8 welding line 9 sealing space 10 processing table 11 suction hole 12 ventilation pipe 14 exhaust pump 20 exhaust pipe 30 cooling pipe passage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Koga 3-1-1 Higashikawasakicho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries Ltd. Kobe factory (72) Inventor Masayuki Inuzuka Higashikawasaki, Chuo-ku, Kobe-shi, Hyogo 3-1-1, Kawasaki Heavy Industries, Ltd. Kobe factory (72) Inventor Hiroshi Hase 3-1-1, Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries Ltd., Kobe factory (72) Inventor Nishio Mamoru Hyogo 3-1, 1-1 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Kawasaki

Claims (6)

[Claims] 1. A method of welding a laminated structure comprising an outer panel and a reinforcing member integrally formed with ribs and joints, wherein the joint of the reinforcing member and the outer panel are in close contact with each other. To
A welding method for a laminated structure, characterized by irradiating a laser beam from the reinforcing member side to heat and melt a region from the surface of the reinforcing member to the inside of the outer panel, and joining the outer panel and the reinforcing member. . 2. A plate-shaped member having a recessed portion formed in at least one side thereof is brought into close contact with each other to form a sealed space in the recessed portion, and the pressure in the sealed space is reduced below atmospheric pressure. The pressure difference increases the adhesion of the plate-shaped members, and the portion where the plate-shaped members are in close contact with each other is irradiated with a laser beam from one plate-shaped member side, so that the surface of one plate-shaped member is A laser welding method, characterized in that a region up to the inside is heated and melted and joined. 3. The laser welding method according to claim 2, wherein the two plate-shaped members are brought into close contact with each other and then temporarily fixed by resistance spot welding. 4. The two plate-shaped members are placed on a processing table having a large number of suction holes, and the gap between the other plate-shaped member and the processing table is sucked from the suction holes to obtain the other plate. The laser welding method according to claim 2, wherein the plate-shaped member is brought into close contact with the processing table. 5. The laser welding method according to claim 4, wherein the processing table is cooled to absorb the processing heat of the plate-shaped member. 6. A machining table in which a large number of suction holes are formed on a work placement surface, a ventilation pipe line communicating with each suction hole, an exhaust unit for exhausting the ventilation pipe line, and the machining table. A processing table device comprising: a cooling pipe line for circulating a cooling medium to be cooled.