JPS58100980A - Seam welding machine - Google Patents

Abstract

PURPOSE:To generate a normal nugget and improve the quality of weld zone by detecting consumption of a pair of circular electrodes for seam welding and providing a device that controls the current density between each circular electrode and an object to be welded at constant value by inputting the signal. CONSTITUTION:Electrode consumption detecting devices 10, 11 are provided on the frame 1 of the main body and radial consumption of upper and lower circular electrodes is detected. For instance, when the upper circular electrode changes to smaller diameter, a driving rod 16 is pushed down by a pressure cylinder 6. Thus, a differential transformer 17 detects consumption of the circular electrode 2, and converts it to an electric output signal. Consumption of the lower circular electrode is detected similarly. Signals of detecting devices 10, 11 are sent to a controlling device and operated, and a welding current controlling signal that makes the current density between circular electrodes 2, 3 and an object 23 to be welded constant is outputted. By this way, good welding condition can be maintained at all times, and roughing of the surface of welded object 23 and tread of electrode can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seam welding machine for improving the strength of a bath welding part in seam welding and for obtaining a sound nugget.

Conventionally, in seam welding, even if the diameters of the upper and lower disc electrodes are reduced due to wear due to tactile operation, the welding current is always constant.

In this case, the large diameter of the 10-d disc electrode is greatly reduced, and only in this case should it be replaced with a new disc' electrode accordingly.

However, even in the process of decreasing the diameter of the upper first disc, nuggets are less likely to form at the designated portions of the objects to be welded, making it difficult to maintain good bath contact conditions. -again-
There is also the problem that due to wear of the heat disc's diameter pole, the surface of the mounting plate (11) becomes rough or the electrode tread surface becomes rough.In addition, in the case of 7-meter bath contact to a plated steel plate, the diameter of the upper and lower disc electrodes As the current density decreases and the current density becomes low, there is a risk that cranking may even occur. It was discovered that the current density in the contact area and the workpiece increases by itself.

The present invention has been developed in view of these circumstances, and is capable of producing a normal no-get at the part to be welded of the welded objects, and also prevents defects such as roughness and cracks on the surface of the welded objects. Moreover, it is possible to prevent roughness and abnormal wear of the electrode tread surface, thereby preventing the upper and lower discs**
It is an object of the present invention to provide a seam welding mechanism that allows continuous effective use of an electrode even if the diameter is reduced.

In order to achieve such an object, the first aspect of the present invention is to provide a pair of upper and lower disc electrodes for contacting a seam bath, which transfer the workpiece by clamping and pressing, and a bath fitting for supplying welding current to each of the disc electrodes. a current supply means, an electrode consumption detection means for detecting the amount of consumption in the radial direction of each of the disc ridges; and an electrode consumption detection means connected to the detection means;
A control device that calculates the detected t-bale consumables as an electrical input signal and outputs a welding current limiter signal that keeps the current density between each disc electrode and the workpiece constant. This invention relates to a seam welding machine characterized by:

The second feature of the present invention is to provide a pair of upper and lower disc electrodes for seam welding that presses and transfers the workpiece to be welded, and a welding current supply means that supplies welding current to the welding plate electrodes in each of the front W1 circles. electrode consumption km measuring means for detecting the amount of consumption in the radial direction of the plate electrode;
Connected to this detection means, the detected amount of electrode consumption is calculated as an electrical input signal, and the supply power is gradually reduced or controlled by controlling the flow rate and rest time of the welding current supplied to each disc electrode. The present invention relates to a seam welding machine characterized by comprising a control device for controlling the seam welding machine.

Hereinafter, a first embodiment of the present invention will be explained with reference to FIGS. 1 to 3.

In the figure, 1 is a main body frame, and 2 and 3 are a pair of upper and lower disc electrodes. -The rotation shaft 4 of the upper disc electrode 2 is the main body foot-
It is supported via a pressurizing cylinder 6 on the negative side of the system 1 in a +# lowering function. In addition, the rotating shaft 7 of the lower disc' polarization 3
is supported by a lower stand 8 of the main body frame l via a height adjustment jack 9 so as to be movable up and down. Further, the main body frame 1 is provided with electrode wear amount detection means 10.11 for detecting the amount of wear in the radial direction of each disc' electrode 2.3.

The wear amount detection means 10 of the upper disc electrode 2 includes an adjustment bolt 14 screwed into the side surface of the rotary bearing case 12 of the electrode 2 through a bracket 13 so as to be movable back and forth, and a different bracket 15 on the main body frame 1. Through its drive rod 16
and a differential transformer 17 mounted 9 facing the bolt 14. That is, when the pole 2 of the upper disk changes to a smaller diameter due to wear during welding, the position of the rotary bearing case 12 changes downward by the pressure cylinder 6, and the bolt 14 or the drive rod 16 of the differential transformer 17 is It will be in a state where it is pushed down further than the intended position. The differential transformer 17 detects the amount of wear of the upper disc electrode 2 through the depression of the drive rod, and converts it into a differential output signal.

The wear amount detection means 11 of the lower disc electrode 3 has a configuration that is almost vertically symmetrical to the above-described wear amount detection means of the upper disc electrode 2. That is, the drive rod 20 of the differential transformer 19, which is attached to the lower stand 8 through a bracket 18 so as to be able to be raised and lowered integrally, is opposed to the adjustment bolt 22 which is inserted into the main body frame 1 through a different bracket 21. I'm letting you do it. Similarly to the differential transformer 17 on the upper disk electrode 2 side, the differential transformer 19 obtains the amount of wear of the lower disk electrode 3 as an electrical output.

In the figure, reference numeral 23 denotes an object to be welded, and 24 is provided on the main body frame 1, and connects the object 23 to each disk cage pole 2 via an arm 25.
．． The welding current supply means 3 supplies the welding current to the electrode wear amount detected by the electric detection means 10.11 as an electrical input signal 2, and calculates the amount of electrode consumption detected by the electric detection means 10.11 as an electrical input signal 2. A control device W is connected to output a sub-control signal for the bath junction "a" to keep the current density constant between the two. This control device guides the minute voltage obtained from the differential transformer 17. The voltages are compared and calculated to generate an output signal.In this control device, the current density decreases as the contact area with the workpiece 23 decreases as each disk electrode 2.3 wears out. The rate of increase in the welding current is corrected experimentally in advance, and the set value for welding current control necessary for the nugget to be generated at the center of the weld is adjusted to the differential transformer 17
．． ml is stored in relation to the pushing amount of each of the 19 drive rods 16 and 20.

According to such a configuration, even when each disk electrode 2.3 is consumed during welding work and the contact area of the joint with the workpiece 23 becomes small, the control device controls the current Y[f Since the degree of welding is always maintained constant, a normal nugget can always be generated at the part of the workpiece to be welded. Therefore, despite the reduction in electrode diameter, a good bath contact condition can always be maintained, and the surface of the workpiece to be welded can be prevented from becoming rough or overheated. j! , it is possible to reliably prevent roughness of the tread surface. By keeping the current density constant, it is possible to prevent the racking that occurs in conventional seam welding to steel plates.

Next, a second embodiment of the present invention will be described. That is, in the embodiment of the first invention, the control device has a control function to keep the welding current density constant, but in this embodiment, by controlling the welding current energization and rest time, the total It has a control function to gradually reduce or control the current supply density, that is, the actual amount of power supplied.

According to such a configuration, it is not possible to directly make the welding current density constant, but it is possible to control the actual current supply density to be constant by controlling the welding current application and rest time, which is better than the conventional welding current density. Unlike the conventional case where the current density increases directly with the consumption of the plate electrode and induces many of the above-mentioned cases, such permanent cases can be prevented. In other words, substantially the same effects as in the first embodiment can be achieved.

For example, this device can control the transfer speed of the workpiece 23 □
In response to the change, during cylinder speed transfer, the relationship between energization and pause time is set to 2:1.3:2.2:2...Gin, and during low-speed transfer, the relationship between energization and pause time is set to 2: 2.3:3.2:3・
. . . or 3:2, 4:2, etc., and in this way, the time relationship during high-speed and low-speed transfer can be changed.

In each of the above embodiments, the electrode consumption f! : Although the differential transformer 17.19 provided in the rotating bearing portion of each disc' electrode 2.3 is used as the egress means 10.11, the present invention is not limited to such a device, and can also be applied to Column amount detection means and 1
It is possible to apply various other configurations with 7.

For example, as shown in FIG. 4, potentiometers 27 and 28 may be used instead of the differential transformer.

As shown in Figures 5 and 6, each disk electrode 2.3
A configuration may also be adopted in which rotationally driven knurl rollers 29, 30 are used. That is, knurl roller 29.3
0 are connected to the cylinder equipment ft33.34 via brackets 31.32, respectively, and each of the brackets 31.32
may be connected to differential transformers 37 and 38 via Holts 35 and 36, respectively.

Further, in each of the above embodiments, a mechanical detection section is used as the electrode consumption detection means, but the present invention is not limited to such a detection structure, but can also be directly electrically detected. be. For example, FIG. 7 shows a circuit configuration for detecting the amount of electrode consumption based on changes in the welding secondary voltage.

That is, a reference voltage generator 40 is connected to a timer contactor 39 for seam welding, and this reference voltage generator 4
0 is set at l~ so as to generate a reference voltage that can generate a good nugget. On the other hand, by comparing the secondary voltage from the secondary voltage circuit supplying the secondary voltage to each disk electrode 2.3 via the welding transformer 41 with the reference voltage from the reference voltage generator, A comparator 42 is provided to detect the voltage difference between them. An output terminal 43 is derived from this comparator 42, and the output of this output terminal 43 is fed back to the timer contactor 39 described above.

In this more flexible configuration, if the contact field becomes smaller due to each disc electrode 2.30 mm, the electrical resistance of the contact area increases, and the secondary voltage must be set to a certain standard. Based on the fact that the difference voltage obtained by comparison with the voltage becomes higher, the amount of wear of each disk electrode can be detected.

As described above, the present invention uses a current density control device based on the first invention and a current application weight time control device based on the second invention to adjust the welding current based on the amount of wear in the radial direction of the disc electrode. Since the energization weight time is controlled, unlike the conventional method in which changes in current sensitivity are left unattended, the position of nuggets generated due to wear of the disc electrode, and the roughness of the surface of the workpiece, can be controlled. It is possible to solve the conventional problems related to roughness or cracks on the electrode tread surface and achieve the desired purpose.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention,
Figure 1 is a side view, Figure 2 is a front view, Figure 3 is a different 11
11, FIG. 4 is a front view of a portion showing another embodiment of the present invention, FIG. 5 is a hemostasis diagram of a portion showing still another embodiment of the invention ν1, and FIG. The plan view of the figure and FIG. 7 are circuit diagrams showing a different embodiment of the present invention. 2.3... Disc chamber (umbrella, 1.0.11... Electrode depletion detection means. Agent: Tatsuyuki Unuma (?゛1 or 2 people) (+2) 3[:1 Figure)'' 2 Ro□Nu No. 3 L+ Fig. 4 No. 5 No. 7 -

Claims (2)

[Claims] (1) A pair of upper and lower disc electrodes for seam welding that clamps and transfers the object to be welded, and welding 'i1f to each disc electrode. a bath contact current supply means for supplying current; an electrode wear rate detection means for detecting the amount of wear in the radial direction of each of the disc electrodes; A seam welding machine comprising: a control device for outputting a bath welding current control signal to maintain a constant current density between each disk electrode and the object to be bathed; . (2) A pair of upper and lower circles and electrodes for seam welding that clamps and transfers the object to be bathed, a bath welding current supply means that supplies bath welding current to this valley disk electric member, and each circle in MiJ. An electrode consumption amount detection means for detecting the amount of consumption in the radial direction of the plate electric damage, and an electrode consumption amount detection means connected to this detection means, and the detected ``city pole consumption point'' is applied as an electrical input signal to each of the disk electrodes. By controlling the energization and rest time of the welding current, it is possible to
1. A seam welding machine characterized by comprising a control device for gradually decreasing or controlling t.