JP4868223B2 - Method and apparatus for joining dissimilar metal panels - Google Patents

Description

The present invention relates to a technique for joining dissimilar metal materials, and in particular, one or both of the metal panels to be joined is a material that forms a strong oxide film on the surface, such as an aluminum material or a magnesium material. The present invention relates to a joining method of dissimilar metal panels related to the combination and a joining apparatus applied to such joining.

  Conventionally, in the joining of dissimilar materials using a high energy beam such as an electron beam or a laser beam, the defocused high energy beam is applied to the high melting point material side in order to suppress the formation of brittle intermetallic compounds. A method has been used in which the low melting point material side of the bonding interface is melted and bonded by irradiation and heat transfer from the high melting point material side.

In such a case, the welding conditions are controlled, only the material on one side (low melting point material) is melted at the joining interface, and the growth of the intermetallic compound layer is suppressed by joining using the diffusion of the material. By reducing the thickness, it is considered that the strength per unit area of the joint can be increased as compared to the case where both materials are melted and joined together. In addition, a method is described in which a steel plate is stacked on an aluminum alloy and a laser beam is irradiated from above the steel plate to join different materials with the interface in a solid phase / liquid phase state.
“Overview of the National Conference of the Japan Welding Society”, Japan Welding Society, April 2003, Vol. 72, p. 152

  However, since a dense and strong oxide film is formed on the surface of the aluminum alloy, even in the above-described method in which only the material on one side is melted, in order to remove the oxide film, a large amount of heat is input at the time of joining. Therefore, as a result of the growth of the thick intermetallic compound layer, there is a problem that there is a high possibility that the joint portion has a low strength.

Also, in this method, the aluminum alloy at the joint interface is melted by heat transfer from the steel plate. Therefore, the steel plate must be stacked on the aluminum alloy, and the laser beam must be irradiated from the outer side of the steel plate side. There were structural design constraints.
That is, for the purpose of improving fuel efficiency and athletic performance by reducing the weight of the vehicle, a vehicle body structure using a light alloy such as an aluminum alloy is required for the vehicle body panel, but in order to enhance the performance improvement effect by lowering the center of gravity, When an aluminum alloy is used for the roof panel, the joint structure between the steel member and the aluminum alloy member, which is a vehicle body skeleton structure, is formed by stacking the roof panel made of an aluminum alloy on the steel member, and from the proximity of the laser head, Because the joint structure must be irradiated with the laser beam from the outside of the body frame structure, that is, the side of the aluminum alloy roof panel, the method of irradiating the laser beam from the steel plate side as described above cannot be applied. become.

The present invention has been made in view of the above-described problems in the joining technique of dissimilar metal materials including a material that produces a strong oxide film on the surface, such as an aluminum alloy. However, even if a strong oxide film is present at the bonding interface, high-strength bonding is possible without applying large heat input, and the irradiation direction of the high-energy beam is from one panel side. It is an object of the present invention to provide a bonding method for dissimilar metal panels that is not limited to the above-described method and a bonding apparatus that can be suitably used for bonding different materials.

  As a result of intensive studies to achieve the above object, the present inventors have radiated a high energy beam to both dissimilar metal panels to be joined, that is, not only the side of the refractory metal panel but also oxidation. The inventors have found that the above problem can be solved by irradiating the surface of the coating with a high energy beam, and have completed the present invention.

That is, the present invention is based on the above knowledge, and in the joining method of dissimilar metal panels of the present invention, metal panels made of different materials, at least one of which forms a strong oxide film on the surface When the first metal panel and the second metal panel made of are overlapped and joined, a high energy beam is applied to the joining surfaces of both the first and second metal panels from a direction substantially perpendicular to the joining line. While irradiating, both panels are relatively pressurized and these panels are joined to each other continuously or intermittently.

Further, the dissimilar metal panel bonding apparatus of the present invention is disposed so as to be relatively movable with respect to the bonded panel, and continuously applies a high energy beam to the bonded surface of the bonded panel while continuously or intermittently moving relative thereto. And an irradiating head that irradiates automatically or intermittently, and a pressure roller that presses the bonded portion of the bonded panel while moving together with the irradiating head.

  According to the present invention, both of the dissimilar metal panels to be bonded are irradiated with a high energy beam, and the high energy beam is directly irradiated onto the bonding surface of both metal panels, thereby being generated on the bonding surface. Since not only the strong oxide film, but also various contaminants including the plating layer are removed from the bonding interface, a strong bonding state between the new surfaces of both panels can be obtained. In addition, since the high energy beam is applied to both of the joint surfaces of both panels, the beam irradiation direction is not restricted only from one panel side.

  Below, the joining method of the dissimilar metal panel of this invention is demonstrated further in detail and concretely.

In the method for joining dissimilar metal panels of the present invention, dissimilar material joining between metal panels made of a material that forms a strong oxide film on the surface, or a dissimilar material between a metal panel made of such a material and another general metal panel. At the time of joining, not only the high melting point panel but also the joining surfaces of both metal panels are directly irradiated with a high energy beam, and as described above, a strong intervening at least one joining surface is provided. By removing the oxide film and the plating layer formed on the other joint surface and relatively pressing both panels heated by beam irradiation, the new surfaces of both panels are joined to each other, resulting in a strong joined state. It can be. Further, the bonding interface can be activated by directly irradiating the bonding interface with the high energy beam.
In other words, since the oxide film on the bonding surface is removed by direct irradiation with a high energy beam, it is not necessary to input a large amount of heat for removing the oxide film, and the formation of brittle intermetallic compounds is suppressed. It is possible to prevent the strength from being reduced.

At this time, in a state where the joining end portions of both panels are simply overlapped, it is not possible to irradiate both the joining surfaces of both panels with a high energy beam. For example, a construction form such as flare joining is adopted. Accordingly, it is necessary to irradiate a high energy beam defocused from a gap between the joint surfaces, with the surfaces that are substantially perpendicular to the panel surface as the joint surfaces.
Therefore, the irradiation head located outside the panel to be joined emits a high-energy beam from a direction that is substantially perpendicular to the panel surface, eliminating the restrictions on the beam irradiation direction, and restricting structural design and welding work. It will be resolved.

  As the irradiation condition of the high energy beam at this time, the oxide film or the like on the bonding surface can be removed, and neither of the two panels is melted, and the metal having the lower melting point by subsequent pressurization. Only the panel melts at the bonding interface, or both panels remain in a solid phase without melting, and the condition that the panel on the high melting point side can be heated to a temperature at which material diffusion occurs is required. .

  In the present invention, a strong oxide film means an oxide film that is dense and strong enough to inhibit good bonding. Specific examples of materials that form such an oxide film include aluminum alloys and magnesium alloys. However, it is not limited to this.

In the method for bonding dissimilar metal panels according to the present invention, a high-energy beam is irradiated while being relatively moved with respect to both panels (bonded panels), and a pressure roller disposed near the rear of the irradiation point of the high-energy beam. Both panels can be joined while pressurizing, and at this time, continuous linear joining can be achieved by making the relative movement of the high energy beam to the panel to be joined and the irradiation of the high energy beam continuous. It becomes possible, and continuous linear joining that contributes to improvement in vehicle body rigidity and strength can be realized with high productivity.
On the other hand, if the relative movement of the high energy beam and the timing of irradiation are made intermittent, it is possible to perform spot-like or stitch-like joining.

  As described above, the dissimilar metal panel joining apparatus of the present invention is disposed so as to be relatively movable with respect to the joined panel, and has a high energy on the joining surface of the joined panel while continuously or intermittently relatively moving. Since the apparatus includes an irradiation head that continuously or intermittently irradiates the beam, and a pressure roller that presses the bonded portion of the bonded panel while moving with the irradiation head, it is suitable for the above-described bonding method of the present invention. Can be used.

Further, in the dissimilar metal panel joining method of the present invention, the first metal panel is a light alloy panel such as an aluminum alloy or a magnesium alloy, and the second metal panel is made of a steel plate such as a galvanized steel plate. It can be used as a car body member of an automobile. By using such a member, a light-weight and high-performance vehicle body structure can be obtained inexpensively and easily. For example, a low-melting-point metal panel can be used as a roof panel. Thus, a lightweight and low center of gravity vehicle body can be easily manufactured at low cost.

  Hereinafter, the present invention will be specifically described based on examples.

Example 1
FIG. 1 is a schematic view showing an example of a bonding apparatus for dissimilar metal panels used in the present invention. A bonding apparatus 10 shown in the figure is an irradiation head 11 that irradiates an Nd-YAG laser, which is a kind of high energy beam. The irradiation head 11 and the pressure roller 12 are movably supported by arms A1 and A2 of the welding robot, respectively. The pressure roller 12 is supported by the irradiation head 11. It follows and moves continuously or intermittently.

The irradiation head 11 is connected to a laser oscillator (not shown) via an optical fiber 14 and directs a laser beam B whose focus is adjusted from the tip thereof toward a bonded panel composed of the first metal panel 1 and the second metal panel 2. Can be irradiated.
On the other hand, the pressure roller 12 can press the first metal panel 1 against the second metal panel 2 by a pressure cylinder 13 and pressurize both the panels 1 and 2.

  In the bonding apparatus 10 having such a structure, continuous linear bonding can be performed by continuously moving and irradiating a laser beam, and dot-like by intermittently moving and moving the irradiation. Alternatively, stitch-like joining can be performed.

FIG. 2 shows a procedure for joining an aluminum alloy roof panel 1 (first metal panel) to a steel body member 2 (second metal panel) using the joining device 10 described above. As shown in the figure, the steel rail inner 21 (plate thickness: 1.4 mm), rail outer 22 (plate thickness: 0.8 mm), and side outer 23 (plate thickness: 0.8 mm) are assembled by welding. The roof panel 1 (plate thickness: 1.0 mm) made of an aluminum alloy is flared from the side outer 17 of the vehicle body member 2 from the lateral direction.
The side outer 23 is made of a galvanized steel sheet having a surface plated with zinc.

On the other hand, in the roof panel 1 made of aluminum alloy, the flange-shaped joint surface 1a formed at the end thereof is opposed to the joint surface 23a set on the side outer 23 of the vehicle body member 1 via a gap, and from this gap The defocused laser beam B is irradiated toward both the joint surface 1 a of the roof panel 1 and the joint surface 23 a of the side outer 23.
At this time, the irradiation position of the high energy beam B is a surface where the two panels are finally overlapped, and while irradiating the laser beam B, both panels are substantially perpendicular to the irradiation direction of the laser beam by the pressure roller 12. Relative pressure is applied in the direction of

  3A and 3B show the vicinity of the laser beam irradiation section in FIG. 2, and the irradiation head 11 and the pressure roller 12 of the laser beam B are, as described above, the panel to be joined, that is, The steel body member 2 and the aluminum alloy roof panel 1 are arranged so as to be movable relative to each other. First, as shown in FIG. And the vicinity of the joint is heated to a predetermined temperature.

As the laser beam B, an Nd: YAG laser can be used to remove the oxide film formed on the joint surface 1a of the roof panel 1 and the galvanized layer on the joint surface 23a of the side outer 23. These joint surfaces 1a , 23a is not melted, and only the joining surface 1a is melted by the subsequent pressurization, and the laser defocus diameter, laser output, and feed rate are adjusted so that the two panels can be heated to a temperature that can be joined. Set.
Specifically, using a laser oscillator with a maximum output of 3 kW and a lens with a focal length of 150 mm, the beam B is defocused so as to have a spot diameter of 3.5 mm on the irradiated surface, and the laser output is 0.8 kW and the feed speed. Was applied at 0.7 to 1.0 m / min. During the laser irradiation, argon gas was flowed at a flow rate of 25 L / min to shield the joint.

  Immediately behind the beam irradiation position, as shown in FIG. 3B, the flange-like portion of the roof panel 1 is pressed against the heated joint surface 23 a of the side outer 23 by the pressure of the pressure roller 12. As a result, the roof panel 1 is in close contact with the side outer 23 of the vehicle body member 2, and the joint surface 1 a of the aluminum alloy roof panel 1 is locally melted by heat transfer from the vehicle body member side, and the roof panel 1 and the vehicle body are diffused by material diffusion. The member 2 is joined on the joint surface 23a of the side outer 13.

At this time, when the roof panel 1 made of aluminum alloy is pressed, the vehicle body member 2, which is a structural member made of the steel panels 21, 22, and 23, has a sufficiently high rigidity. Compared to the case of joining with a rivet R as shown in FIG. 5, there is no need for a presser T from the vehicle interior side, so that the joining position and structure of the roof panel 1 and the vehicle body member 2 are relatively free. Since the design freedom is high and the joint flange width can be eliminated, the design freedom can be improved and the design can be enhanced.
Moreover, by directly irradiating the bonding interface with the laser beam B, the energy efficiency for heat input can be improved, the degree of freedom of the bonding structure is high, and the high strength, low cost and light weight unique to continuous bonding. A joining structure can be obtained.

(Example 2)
FIG. 5 shows another example of joining the aluminum alloy roof panel 1 and the steel vehicle body member 2. In the same manner as in the above embodiment, the steel rail inner 21 and the rail outer 23 are welded together. A procedure for joining the vehicle body member 2 and the roof panel 1 made of aluminum alloy will be described.
That is, in this embodiment, as shown in the figure, a curved portion 1b is formed at the joint end portion of the aluminum alloy roof panel 1, and the laser beam B defocused from the gap formed by the curved portion 1b is used. By irradiating both the joint surface of the curved portion 1 and the joint surface 23b of the side outer 23, and then pressurizing the joint portions 1a and 23a of both panels 1 and 23 by the pressure roller 12, these are applied. Both panels 1 and 23 can be similarly joined.

  In this embodiment, compared with the case of the flare bonding in the first embodiment, after irradiation of the laser beam B, both panels in the direction substantially perpendicular to the irradiation direction from the same side as the irradiation head with respect to the bonded panel. The irradiation head and the pressure roller can be both arranged outside the panel to be joined, and by arranging them integrally, the joining apparatus can be simplified. .

It is a schematic explanatory drawing which shows one Example of the joining apparatus of this invention. It is sectional drawing which shows the joining procedure of the dissimilar-metal panel by the 1st Example of this invention. (A) And (b) is explanatory drawing which shows the vicinity of the beam irradiation part in FIG. It is sectional drawing which shows the joint point of the dissimilar-metal panel by the 2nd Example of this invention. It is a schematic sectional drawing which shows the example of a joining structure by the rivet of a steel vehicle body member and an aluminum roof panel.

Explanation of symbols

1 Aluminum alloy roof panel (first metal panel)
1a Joint surface 2 (21, 22, 23) Steel body member (second metal panel)
23a Bonding surface 10 Dissimilar metal panel bonding device 11 Irradiation head 12 Pressure roller

Claims (5)

When the first metal panel and the second metal panel, which are made of different materials and at least one of them is made of a material that generates a strong oxide film on the surface, are overlapped and joined, While irradiating the joint surface with a high energy beam from a direction substantially perpendicular to the joint line , both panels are relatively pressurized to join the panels into a continuous or intermittent line. A method for joining dissimilar metal panels.   2. The method for joining dissimilar metal panels according to claim 1, wherein both panels are flared. The method for joining dissimilar metal panels according to claim 1 or 2, wherein the first metal panel is a light alloy panel, and the second metal panel is a vehicle body member made of a steel plate. The method for joining dissimilar metal panels according to claim 3 , wherein the first metal panel is a roof panel of an automobile body. An irradiation head that is disposed so as to be relatively movable with respect to the bonded panel, and continuously or intermittently irradiates the bonding surface of the bonded panel with a high energy beam while being relatively moved;
A joining apparatus for dissimilar metal panels, comprising a pressure roller that presses a joining portion of a joined panel while moving together with the irradiation head.

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