JPS6321592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seam welding device, and more specifically, to a seam welding device using a resistance welding method that can perform straight line welding with high efficiency.

Note that the meaning of the word welding in this invention includes pressure welding and brazing performed using a seam welding device.

Conventionally, seam welding has been widely used as a resistance welding method that can perform straight line welding with high efficiency, but because it is high-speed welding, if the welding conditions suddenly change and the weld quality becomes unstable, the yield will drop significantly. death,
There was a problem that caused a huge loss. In order to reduce such losses, conventionally it has been necessary to always have a worker at the welding device and to manually make delicate adjustments to the welding conditions.

The present invention aims to solve the above-mentioned conventional problems, and aims to provide a seam welding device equipped with an adaptive control device for automatically maintaining constant welding conditions. It is.

Another object of the present invention is to monitor the amplitude of mechanical vibrations that inevitably occur in the pressurizing system of welding equipment due to electromagnetic vibrations during welding, and to detect excess or deficiency of the molten layer during the welding process. The present invention provides a seam welding device that feeds back the welding speed and automatically adjusts the welding state to an appropriate welding state.

A further object of the present invention is to provide a seam welding device that feeds back the detected excess or deficiency of the molten layer to the welding current value to automatically adjust the welding state to an appropriate state.

Hereinafter, this invention will be explained with reference to the drawings.

1A and 1B are conceptual diagrams for explaining the principle of the present invention and for understanding the mechanical vibration phenomenon of the electrode system during the welding process. In the figure, a disk-shaped upper electrode 1a and a lower electrode 1b are pressed against welded materials 2a and 2b and rotate, and the welded materials 2a and 2b are rotated.
The welding part is energized while moving parts a and 2b. In the welding process, the materials to be welded 2a, 2b
A weld layer 3 and then a weld 4 are formed in between.
A pressure mechanism 5 is mechanically coupled to the upper electrode 1a, and a secondary winding 6 of a welding transformer is electrically connected between the upper electrode 1a and the lower electrode 1b.
In such a device, when electricity is applied for welding, mechanical longitudinal vibration is generated in the upper electrode 1a in response to the electromagnetic force generated in the current-carrying loop. For example, in the case of a 60Hz single-phase AC seam welding device, the main frequency of this vibration is 180Hz. Generally, the lower electrode 1b is integrated with the main body of the welding device and has relatively high rigidity, while the upper electrode 1a is directly connected to the pressurizing mechanism 5, so the upper electrode 1a is
Vibration occurs on the side. Such vibration of the upper electrode 1a is accompanied by repulsive vibration with the highly rigid lower electrode 1b via the welding materials 2a and 2b, resulting in a large amplitude Aa, but even if vibration occurs in the lower electrode 1b, The amplitude is minute as shown by Ab. However, as a result of this inventor's experiment,
Between the upper and lower electrodes 1a and 1b, the molten layer 3 formed directly under the upper electrode 1a acts as a vibration absorber, and the magnitude of this vibration absorption depends on the size of the molten layer 3. It turns out that it depends on.

FIGS. 2A, 2B, 3A, and 3B are for explaining the above phenomenon, and when the molten layer 3 is small as shown in FIG. The amplitude Aa of the vibration is relatively large as shown in Figure 3A. On the other hand, when the molten layer 3 is formed large as shown in Fig. 2B, the vibration absorption effect by the molten layer 3 becomes large, so the amplitude Aa
becomes small as shown in Figure 3B.

From the above, the variation in the size of the molten layer 3 that occurs due to variation in welding conditions can be known by detecting the variation in the amplitude Aa.
Furthermore, if the mechanical rigidity of the seam welding equipment and the material to be welded are constant, the formation state of the molten layer 3 will be
It can be quantitatively evaluated by measuring the size of Aa.

Although this invention is based on the above-mentioned principle,
Furthermore, the adaptive control means of the present invention will be explained with reference to FIG. In the figure, the amplitude A ₁ indicates the limit amplitude reference value on the over-formed side, as shown by the molten layer 3 ₁ , and the amplitude A ₂ indicates the limit amplitude reference value on the under-formed side, shown as the molten layer 3 ₂ . In the figure, when continuous seam welding is being performed, for example, when the amplitude Aa reaches the insufficient limit amplitude reference value _A2 at point P, the amplitude Aa becomes smaller, in other words, the molten layer 3 becomes larger. In this way, the welding speed can be decreased or the welding current can be corrected to increase so that a predetermined molten layer 3 can be obtained. Conversely, when the amplitude 5a reaches the excessive limit amplitude reference value _A1 as at point Q, the amplitude 5a
The correction can be made by increasing the welding speed or reducing the welding current so that a becomes larger, and so that the molten layer 3 becomes smaller.

FIG. 5 shows an embodiment of the first invention, which includes a displacement sensor 7 that detects the relative displacement h between the upper electrode 1a and the lower electrode 1b, an arithmetic unit 8 to which the output signal of the displacement sensor 7 is applied, and a comparator. Adaptive control device 10 consisting of 9
The output signal of the comparison/judgment circuit 9 is used to control the rotational speed of the drive motor 11 that rotates the lower electrode 1b.

Next, to explain the operation, during welding, the relative displacement h of the upper and lower electrodes 1a, 1b is constantly monitored by the displacement sensor 7, and the upper electrode 1a, 1b is constantly monitored by the displacement sensor 7.
The amplitude Aa of the vibration of a is detected. This value is applied to the comparator 9 via the arithmetic unit 8, and is compared with the preset limit amplitude reference values A ₁ and A ₂ shown in FIG. The welding speed is automatically controlled so that the vibration amplitude of the upper electrode 1a is within a certain range, that is, the welding condition is maintained in a good condition.

FIG. 6 shows an embodiment of the second invention, in which a power supply section 12 that supplies current between the upper electrode 1a and the lower electrode 1b.
The configuration is such that the output signal of the comparator 9 of the adaptive control device 10 is added to the output signal of the comparator 9 of the adaptive control device 10. Other parts indicated by the same reference numerals as in FIG. 5 are the same or equivalent parts, and their explanation will be omitted.

Next, to explain the operation, as welding progresses, the displacement h between the electrodes is detected by the displacement sensor 7, the amplitude Aa is measured by the calculator 8, and this value is sent to the comparator 9 and set in advance. The amplitude is compared with the limit amplitude reference values A ₁ and A ₂ , and if it deviates from the range of A ₁ and A ₂ , the ignition timing of energization of the power supply section 12 is adjusted, and the vibration of the electrode is kept within a certain range. In other words, the welding current of the power supply section 12 is automatically controlled so that the welding state is maintained well.

In addition, in each of the above embodiments, a displacement sensor is used as a means for detecting vibration amplitude, but the present invention is not limited to this, and any device capable of quantitatively measuring the amplitude or its change, such as a range finder or an accelerometer, may be used. , the same effect can be obtained in either case.

As described above, the present invention detects the welding state by monitoring the amplitude of the vibrations generated in the electrode, automatically adjusts the welding conditions in real time, and consistently achieves good welding.

[Brief explanation of the drawing]

Fig. 1A is a front view of the main part for explaining the principle of this invention, Fig. 1B is a side view, Fig. 2A,
Figure 2B is also a partial side view, Figure 3A, and Figure 3B.
4 is a diagram similarly showing the amplitude change, FIG. 5 is a system diagram of one embodiment of the present invention, and FIG. 6 is a system diagram of another embodiment. 1a: Upper electrode, 1b: Lower electrode, 2a, 2
b: Material to be welded, 3: Molten layer, 4: Welding section, 5: Pressure mechanism, 6: Secondary winding, 7: Displacement sensor, 8: Arithmetic unit, 9: Comparator, 10: Adaptive control device, 11:
Drive motor, 12: Power supply section. Note that in each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. In a welding device that performs welding while moving the welded material by rotation of a pair of disc-shaped electrodes that press into contact with the welded material, vibrations occurring in at least one of the electrodes an amplitude detection device that detects the amplitude of the
A seam welding apparatus comprising: a device that automatically changes the moving speed of the workpiece so that the amplitude value determined by the amplitude detection device is within a predetermined range of a preset standard. 2. An amplitude for detecting the amplitude of vibration generated in at least one of the electrodes in a welding device that performs welding while moving the material to be welded by rotation of a pair of disk-shaped electrodes that press into contact with the material to be welded. a detection device;
A seam welding device comprising: a device that automatically changes a value of welding current passing through the electrode so that the amplitude value measured by the amplitude detection device is within a predetermined range of a preset standard.