JPS6024746B2 - Pressure welding method that utilizes the heat generated by the unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure welding method for metal members that utilizes Joule heat generation.

As shown in FIG. 1, this type of conventional pressure drop settling method involves sandwiching metal members 1 and 2, which are pressure members, between a pair of pressure electrodes 3 and 4, and applying direct current or commercial frequency power between the pressure electrodes 3 and 4. The metal member 1 is heated by applying an alternating current voltage of
, 2 are pressure welded together.

In this conventional method, when the specific resistance of the metal member 2 is extremely high compared to that of the metal member 1, the Joule heat generation of the metal member 2 is large, so that Before the metal member 2 is heated to a temperature suitable for compression, the interior 2b of the metal member 2 in the vicinity of the pressure contact surface 2a becomes molten, and the molten metal 2c may scatter as shown by the arrow in the figure. When scattering occurs, the pressing force from the pressurizing electrodes 3 and 4 is insufficient and the metal members buckle, making it difficult to press, and the scattered molten metal 2c adheres to the metal members 1 and 2, making it impossible to use them as products. This phenomenon occurs not only when the specific resistances of the metal members 1 and 2 are different, but also when the shapes of both metal members are considerably small.

This invention was made in order to eliminate the above-mentioned conventional drawbacks.In the initial stage of energization, the frequency of the pressure welding current is made higher than at least the commercial frequency to make the skin effect noticeable, and furthermore, the frequency of the pressure welding current is By changing the value as the energization time elapses, it is possible to eliminate the risk of partial melting of parts other than the flat surface of the metal member, and the Joule heat generation can maintain the rear surface at the optimum temperature. The purpose of the present invention is to provide a compression twill welding method that utilizes.

An embodiment of the present invention will be described below with reference to the drawings. Second
In the figure, 5 is a commercial frequency three-phase AC power supply, 6 is a full-wave rectifier using a thyristor, 7 is an LC smoothing filter,
8 is a frequency converter such as a variable frequency inverter, which converts the rectified output of the full-wave rectifier 6 into single-phase alternating current and outputs the same.

Reference numeral 9 is a control bag counterfeit, which has an energization time setting function and controls the output frequency of the frequency converter 8, for example, to gradually reduce it from a predetermined frequency higher than the commercial frequency as the energization time t elapses. A frequency control signal f is sent to the frequency converter 8.

10 is a transformer.

FIG. 3a shows the pressure drop current 1 output from the frequency converter 8.
This current is applied to the metal members 1 and 2 via the pressure electrodes 3 and 4. At the initial stage of energization, a high-frequency current flows through the metal members 1 and 2, so Joule heat generation occurs in the surface layer ld of the metal member 1 and the surface layer 2d of the metal member 2, as shown in FIG. 4, due to the skin effect. is larger than the pond part, and as the frequency decreases, Joule heat generation in the other parts increases. Therefore, by determining the above-mentioned initial frequency of energization and its energization time t in accordance with the materials, shapes, etc. of the metal members 1 and 2, the pressure saddle surface portion 2 of the metal member 2 can be
The temperature of the pressed surface portion 2a can be raised to the pressing temperature before a melted portion is generated in the internal portion 2b near a. Furthermore, as shown by the dotted line in FIG. 2, the control device 9 sends a peak value control signal h to the full-wave rectifier 6, and increases the rectified output as the energization time t elapses.
When the pressure saddle current 1 as shown in FIG. Even if it is enlarged, the temperature of the indentation surface portion 2a can be maintained at approximately the optimum temperature for indentation.

As described above, according to the present invention, at the initial stage of energization, the frequency of the pressure welding current is raised higher than the commercial frequency to actively utilize the skin effect, so that the melted portion of the pressure saddle surface of the metal member is formed in the vicinity thereof. Since the temperature can be raised to the compression temperature before the melting occurs, even if the specific resistances of the metal parts to be compressed and settled are greatly different or the shapes of the metal parts are small, the melting near the pressure saddle surface as in the conventional method can be avoided. , metal members can be pressure-welded to each other without buckling of the metal members or contamination of the product due to scattering of molten metal, and furthermore, the current value of the pressure bush current can be increased as the energization time elapses. As a result, even if the zero-pressure bush surface portion of the metal member expands during rutting, the optimum pressure saddle temperature can be maintained, so that the metal members can be bonded to each other in the pressure saddle with a certain level of strength. can.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the conventional pressure welding method, Fig. 2 is a block diagram of an embodiment of the pressure twill welding method according to the present invention, and Fig. 3 is a diagram for explaining the pressure twill welding method according to the present invention. The waveform diagram and FIG. 4 are explanatory diagrams of the operation of the above embodiment. 0 In the diagram, 1, 2...Metal Department Village, 3, 4...
...・Pressure electrode. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Figure 1 Figure 4 Figure N Boat chart

Claims (1)

[Claims] 1. In the case where two or more metal members are sandwiched between pressure electrodes and the metal members are welded together using pressure and welding using pressure generation, at least a pressure welding current of a frequency higher than the commercial frequency is applied to the above at the initial stage of energization. A pressure welding method using Joule heat generation, characterized in that a metal member is energized to produce a skin effect, and then the frequency of the pressure welding current is reduced as the initial period of energization progresses. 2. In the case where two or more metal members are sandwiched between pressure electrodes and the metal members are welded together by pressure welding using the joule heat generation, a pressure welding current having a frequency higher than the commercial frequency is applied to the metal members at least in the initial stage of energization. A pressure welding method that uses Joule heat generation, which produces a skin effect, and thereafter reduces the frequency of the pressure welding current as the energization period passes, and increases the current value of the pressure welding current as the energization time passes after the start of energization. Welding method.