JPS5942189A - Resistance welding method of laminated plate - Google Patents

Abstract

PURPOSE:To perform stably welding with always excellent welding quality in the stage of spot-welding laminated plates to each other by conducting electricity onto the metallic plate of one of the laminated plates and pressurizing the welding spot of both laminated plates with electrodes. CONSTITUTION:The metallic material 7a of a laminated plate 7 and the metallic material 8b of a laminated plate 8 are pressurized in the position where these materials face to each other by electrodes 9, 10 and a voltage is applied thereto with a voltage transformer 11 in the stage of spot-welding the laminated plates 7, 8 consisting of non-conductive materials 7c, 8c of plastics or the like sandwiched with the metallic materials 7a, 7b and 8a, 8b. The electrode 10 having a large contact area is placed on the material 7a of the plate 7 apart by a prescribed distance therefrom and is connected to a terminal differing from the electrode 9 in the transformer 11. Electric current flows from the electrode 9 to 12, and since the electrode 9 has a small sectional area, the materials 7c, 8c are melted and extruded by the temp. elevation resulted from the large current density, by which the electrodes 9 and 10 are conducted to each other and the laminated plates are spot-welded 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resistance welding method such as spot welding of two or more lap joints of laminated plates containing non-conductive materials or of a laminated plate and a metal plate.

In general, since laminated plates are non-conductive materials, it is impossible to conduct electricity in the thickness direction of the plate, and resistance welding such as spot welding cannot be performed as is. Therefore, conventionally, as shown in Fig. 1, the metal skin materials 1a and 2b of the laminate plate 1.2 are short-circuited by the conductive material 3 held and fixed to the clamp device #4, and the metal skin material between them is heated by electrical current. At the same time, a method has been adopted in which the joint portion is welded by applying pressure with electrodes 5 and 6. Note that if the clamp device 4 is electrically conductive, the electrically conductive material 3 is only required.

However, in this case, a conductive material 3 for shorting, a clamping device 4 for the same, and man-hours are required, and depending on the shape of the product, there are problems such as the shorting part not being removed, resulting in extremely low productivity. Ta. In addition, the time to break the 7i8 green of the laminate changes depending on the shorting material and how it is clamped, or depending on the position from the welding point, so the nugget formation time varies with respect to the preset total energization time. Welding quality tends to be unstable.

The purpose of the present invention was made in view of the above-mentioned drawbacks, and it is possible to always obtain stable welding quality under stable welding conditions, and to achieve high productivity (also, it is possible to weld IF screw joints of three or more sheets). A method for resistance welding laminates is provided.

In order to achieve such an object, the method of the present invention involves welding two output terminals of a power transformer to the part to be joined in a method of resistance welding one laminate to another or a laminate to a metal plate. At the same time, the electrodes connected to the power transformer terminals having the opposite polarity to one electrode on the same metal skin material or the same metal plate are separated by a certain distance from each other. The two electrodes are placed in the same direction, and electrical current is applied under pressure.Finally, resistance welding is performed by direct electrical current between the opposing electrodes.

”: J, below, the method of the present invention will be explained using the examples shown in the figures.

No. 21 is a cross-sectional view showing an example of the structure of the laminated plate 7 (8), where symbols 7a (8a) and 7b (8b) are metal skin materials, and 7c
(8c) is the gold m5'f-skin material 7a (8a), 7b (8
b) It s sandwiched between plastic, nylon, etc.
+= It is a non-conductive material consisting of carbon.

Now, a method of resistance welding a laminate according to the present invention will be described below with reference to the drawings in the case of spot welding.

Figure 3 shows the two laminated plates shown in Figure 2.
An example of r8 reed is shown. The parts sandwiched by electrodes 9 and 10 are the parts to be joined, and the respective 'electrodes 9 and '1
0 are wired to the output terminals 11a111'b of the power transformer 11, respectively. -! ! Furthermore, an electrode 12 is arranged on the same metal skin material 711 as the electrode 9 at a constant distance, and the electrode 12 is in contact with the output terminal 11b side of the L source transformer 11.

In this embodiment, the contact area of the 4-pole 12 with the metal skin 7a is wider than that of the electrode 9.10, but this electrode 12 has the same shape as the electrode 9.10. 13υ is a receptor for the electrode 12.

Under such electrode arrangement, welding is possible between electrodes 9 and 10 by applying pressure to the electrodes and energizing them. As shown in the figure.

That is, FIG. 4 shows the initial state of energization, and because of the non-conductive material 7c, the current flows through the metal skin material 7a as shown by the arrow A in the figure (
7t, where this current concentrates directly under the electrode 9, becomes high temperature, and due to this heating and pressurization, the non-conductive material 7c directly under the direct electrode 9 is softened, becomes molten, and is extruded. As a result, conduction is established between the electrodes 9 and 10, and the fifth
The state shown in the figure will be reached. That is, the total welding current A is divided into a current B flowing through the metal skin material 7a and a current C flowing toward the electrode 10. On the other hand, since the specific resistance is smaller between the electrodes 9 and 10 than between the electrodes 9 and 12, the current C The current C is overwhelmingly larger than the current B. The generation of nuggets indicated by the reference numeral 14 in FIG. .In addition, Fig. 7,
As shown in FIG. 8, if the contact area of the electrode 12 with the metal skin material 7a is made to be about the same as that of the electrode 9.10, it is possible to obtain conduction directly under the electrode 12. This is effective when the non-conductive material layer is relatively thick. In this case, at the initial stage of energization, the current flows as shown in Figure 4, and after that, the time course is as shown in Figures 7 and 8, and the current to create the nugget is ultimately a direct current. D′f!
: Can be welded easily. Note that E, F, and G are metal skin materials 7.
a, 7 b This is the current flowing through ssa. In this case, there is no intention to create a nugget directly under the electrode 12, so the meaning is fundamentally different from series welding, and the current is ultimately passed directly between the electrodes 9 and 10 of the part to be joined. This is intended to improve the welding quality.

FIG. 9 shows a specific welding apparatus for welding the laminated plate 7 and the metal plate 15 using the method of the present invention. Electrode 9
．． 12 is held by air or hydraulic cylinders 16.17 and is pressurized to the metal skin material 7a of the laminate plate 7 via the cylinders 16.17. Also,
The power transformer 11 is connected to the electrodes 9, 12, and 10 via cables 18, 19, and 20, respectively, and the figure shows the state immediately before commuting. In addition, the power transformer 11, cylinders 16 and 17, electrode 10, and support 13
are fixed to the welding machine main body 21, respectively. If the process is carried out in this state, a nugget of stable quality can be produced between the electrodes 9 and 10 by constant direct energization, and it can be automated as shown in this figure, so productivity is extremely high.

As explained above, according to the resistance welding method for laminates according to the present invention, the heating thread that breaks the electrical insulation of the non-conductive material can be uniquely fixed between the fixed electrodes and by the combination of materials. By determining this, the energization time for nugget generation, which is part of the energization time set once, remains constant even if the welding location changes, and extremely stable welding quality can always be obtained.

In addition, since the flow of current in each weld is direct and IL, it is possible to obtain more stable welding quality than in series welding. Furthermore, since the conventional short-circuit energizing material and the clamping device for fixing the same are unnecessary, costs can be reduced. Furthermore, there is no need for man-hours for fixing materials for short-circuit energization, and welding can be automated, so productivity can be significantly improved. In addition, various excellent effects such as welding of three or more layers, which was impossible with conventional short-circuit energization, are possible.

[Brief explanation of drawings]

1121 is an explanatory diagram for explaining the conventional resistance welding method for laminated plates, FIG. 2 is a sectional view showing the structure of the laminated plate, and FIG.
The figure is an explanatory diagram for explaining the resistance welding method for laminate plates of the present invention. Figures 4 to 6 are explanatory diagrams sequentially showing the seven principles of the method of the present invention. Figures 7 and 8 are explanatory diagrams of the present invention. Explanation 1 and FIG. 9 for illustrating other practical examples of the method are
FIG. 2 is a configuration diagram showing an example of a specific welding device employed in the present invention. 7.8 = -f, & laminate, 7a, 7b, 8a, 8 b
-=metallic skin phase, 7c, 8cm non-conducting '1 package 1ζL material,
9.10.12...'1L pole, 11...power transformer, lla, 11b...t, lS')E terminal. Agent Tatsuyuki Unuma (and 2 others) Figure 1 Figure 2 Figure 3 463 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] (1) In the method of resistance welding between laminates or lap joints between laminates and metal plates, two of the power transformers
At the same time, connect two output terminals to electrodes facing opposite to the parts to be joined, and at the same time connect one of the output terminals to a power transformer terminal having the opposite polarity to that electrode on the same metal skin material or the same metal plate. A method for resistance welding a laminated plate, in which connected electrodes are arranged at a certain distance, energized under pressure, and finally resistance welded by direct energization between the opposing electrodes.