JPS5886985A - Seam welder - Google Patents

Abstract

PURPOSE:To maintain welding conditions automatically constant by detecting the amplitude of the oscillations generated during welding in a disc-like electrode pair which is held in press contact with materials to be welded, to detect welding condition and controlling welding conditions automatically. CONSTITUTION:During progression of welding, the relative displacement (h) of upper, lower electrodes 1a, 1b is monitored at all times with a displacement sensor 7, and the amplitude Aa of the electrode 1a is detected. The amplitude varies with the change in the size of a molten layer. The limit amplitude reference values on the over-forming side of the layer 31 and the under-forming side of the layer 32 are defined as A1, A2 respectively. Said amplitude Aa is applied via an arithmetic device 8 to a comparator 9, by which the Aa is compared with the A1 and the A2 and when the same deviates from the range of the reference values, the number of revolutions of a motor 11 is controlled, by which the welding speed is controlled automatically so as to keep the amplitude Aa within the specified range. It is equally well to control welding current automatically so as to keep the Aa within the specified range. Thus, the welding conditions is automatically maintained satisfactorily.

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 Section 4 of this invention also includes pressure welding and round-welding performed using a seam welding device.

Conventionally, the seam welding method has been widely used as a resistance welding method that can perform straight line welding efficiently, but since it is a bulk welding method,
Once the welding conditions fluctuate and the welding quality becomes unstable, there is a problem in that the yield drops significantly and large losses occur. 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 something.

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. To provide a seam welding device that automatically adjusts the welding speed to an appropriate welding state by adjusting the welding speed.

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

Hereinafter, this invention will be explained using drawing numbers.

FIG. 1 and FIG. 1B are conceptual diagrams for explaining the present invention in detail and for understanding the mechanical vibration phenomenon of the electrode system during the welding process. In the figure, the disk-shaped upper electrode /a and lower electrode /b rotate while being pressed against the welded materials core a and core b, and energize the # contact area while transporting the welded materials λa, Jl). It is. In the welding process, the core of the material to be welded a
, 26, a molten layer 3 is formed, and then a welded portion DA is formed.

A pressure mechanism S is mechanically coupled to the upper electrode /a, and the upper electrode /& and the secondary winding 6 of the lower lower electrode/section welding transformer are electrically connected. In such a device, when current is applied for welding, mechanical longitudinal vibration occurs in the upper electrode/IL in response to the electromagnetic force generated in the current-carrying loop. For example, in the case of a 60 Hz single-phase AC seam welding device, the main frequency of this vibration is /1OH2. Generally, the lower electrode /b is integrated with the main body of the welding device and has relatively high rigidity, while the upper electrode /a is connected to the pressurizing mechanism S.
Since it is directly connected to the upper electrode/IL side, vibration mainly occurs on the upper electrode/IL side. Such an upper electrode/a
The vibration of is accompanied by repulsive vibration between the welded material cores a and 2b and the highly rigid lower electrode kb, resulting in a large amplitude a, but even if vibration occurs at the lower electrode /b, the amplitude is A
As shown in t), it is minute.

However, as a result of this inventor's experiment, the upper and lower electrodes/a
, /1), the molten layer 3 formed directly under the upper electrode /a acts as a vibration absorber, and the magnitude of this vibration absorption depends on the size of the molten layer 3. It turned out that it was.

Figure 15, Figure 8g28, Figure 15, and Figure 3B are for explaining the following phenomena.If the melted layer 3 is small as shown in Figure 1, the upper electrode/ The amplitude Aa of the vibration generated at point a is relatively large, as shown in Figure 15. On the other hand, when the molten layer 3 is formed to be large as shown in FIG. 23, the vibration absorption effect by the molten layer 3 becomes large, so the amplitude Aa becomes small as shown in FIG.

From the above, the variation in the size of the molten layer 3 that occurs due to variations in welding conditions can be known by detecting the variation in the amplitude a.

Furthermore, if the mechanical rigidity of the seam welding device and the material to be welded are constant, the formed layer of the molten layer 3 can be quantitatively evaluated by measuring the magnitude of the amplitude Aa.

This invention is based on the above-mentioned principle, but furthermore,
In FIG. 1 for explaining the adaptive control means of the present invention with reference to FIG. 1, the amplitude A indicates the limit amplitude reference value on the side of excessive formation, as shown when the molten layer is 3m;
．． The limit amplitude reference value on the side of insufficient formation is shown. In the figure, when continuous seam welding is being performed, for example, at point P, the amplitude Aa is the insufficient limit amplitude reference value A.
, the welding speed is lowered or the welding current is corrected to increase so that the amplitude Aa becomes smaller, in other words, the molten layer 3 becomes larger, and a predetermined molten layer 3 is obtained. You can make it possible to Conversely, when the amplitude ja reaches the excessive limit amplitude reference value A, as at point 9, the welding speed is increased or the welding current is reduced so that the amplitude 5a becomes larger, and the molten layer 3 becomes smaller. All you have to do is correct it.

FIG. S shows an embodiment of the first invention, in which the upper electrode /a
The adaptive control device 10 consists of a displacement sensor for detecting the relative displacement between the lower electrode /b and an arithmetic unit 1 to which the output signal of the displacement sensor is applied, and a comparator 9. /kl rotating drive motor/
It is configured to control the rotational speed of l.

゛Next, to explain the operation, during welding, the relative displacement of the upper and lower electrodes /a, /b is constantly monitored by the displacement sensor 7, and the amplitude Aa of the vibration of the upper electrode /IL is constantly monitored.
is detected. This value is added to the comparator 9 via the arithmetic unit 1, and the limit amplitude reference value A shown in FIG. 9 is set in advance.
I + 4, and when it deviates from this reference value range, the rotation speed of the driver /a is adjusted, and the upper electrode /a
The welding speed is automatically controlled so that the vibration amplitude is within a certain range, that is, the welding condition is maintained well.

FIG. 6 shows an embodiment of the second invention, in which the hs electrode la
The configuration is such that the output signal of the comparator t of the adaptive control device IO is applied to the power supply section l that conducts current between the lower electrodes lb. Other parts indicated by the same reference numerals as in FIG. 45 are the same or equivalent parts, and their explanations will be omitted.

Next, to explain the operation, as welding progresses, the displacement between the electrodes is detected by the displacement sensor, the amplitude a is measured by the calculator 1, and this value is sent to the comparator 2, which is set in advance. The specified limit amplitude reference value M1. -Af, and if it deviates from the range of A, , A, the ignition timing force I of energization of the power supply unit 12 is adjusted so that the vibration of the electrode is within a certain range.In other words, the welding The welding current of the power supply unit 1 is automatically controlled to maintain a good condition.

Also, do any of the above! Also, although a displacement sensor was used as a means for detecting vibration amplitude, the present invention is not limited to this.
A similar effect can be obtained using a rangefinder, an accelerometer, etc. that can quantitatively measure the amplitude or its changes.

As described above, the present invention detects the welding state by monitoring the amplitude of vibrations generated in the electric current,
Automatically adjusts welding conditions in real time to ensure consistently good welding.

[Brief explanation of the drawing]

The first sectional view is a front view of main parts for explaining the invention in detail, FIG. 1B is a side view, the third sectional view, and FIG. FIG. 9 is a diagram similarly showing amplitude changes, FIG. S is a system diagram of one embodiment of the present invention, and FIG. 6 is a system diagram of another embodiment. Noa: upper electrode, lb: lower electrode, core a, core b: material to be welded, 3: molten layer, 4I: welding part, S: pressure mechanism, 42 secondary winding, 7: displacement sensor, S : Arithmetic unit, 9: Comparator, l
O: Adaptive control device, //: Drive motor, l control power supply section. In each figure, the same reference numerals indicate the same or 4i-equivalent parts. Agent Makoto Kuzuno - Place 1A figure b Place 1B figure Asahi 2A symbol 3A symbol 2B figure

Claims (1)

[Scope of Claims] (/l In a welding device that performs welding while moving the workpiece by rotation of seven pairs of disc-shaped electrodes that press into contact with the workpiece, at least the -. side of the electrodes It is equipped with an amplitude detection device that detects the amplitude of the generated vibration, and a device that automatically changes the moving speed of the welding material so that the amplitude value measured by the amplitude detection device falls within a certain range of a preset standard. 41) Seam welding equipment with minimal (j) In a welding device that performs welding while moving the welded material by rotation of a pair of disk-shaped electrodes that press into contact with the welded material, an amplitude that detects the amplitude of vibration generated in at least one of the electrodes. It is characterized by comprising a detection device and a device that automatically changes the value of the welding current passing through the electrode so that the amplitude value determined by the amplitude detection device is within a certain range of a preset standard. Seam welding equipment.