JPS6361116B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a groove tracing control device in an automatic arc welding device.

(Prior Art) Generally, in order to perform automatic welding, accurate positioning is required in order to keep the welding arc constant at a predetermined target position of the groove. For this reason, it is considered optimal to detect the relative position between the welding arc and the groove and control the relative position so that this relative position becomes the normal position. Examples of conventional techniques include the following.

1 JP-A-55-45554, JP-A-58-38669 The inside of the groove is imaged by a television camera from a direction parallel to the welding line, and the video signal of the television camera is processed to generate arc light in the direction perpendicular to the welding line. A brightness distribution is determined, and the arc position within the groove of the welding wire is detected from the brightness distribution for control.

2 JP-A-57-62866 A television camera that emits a laser beam toward the welding area and receives the laser beam reflected from the welding area, and a bandpass filter is provided in front of the television camera, and the welding is performed using the image signal received from the television camera. It is controlled by calculating the misalignment between the wire and the groove.

However, these conventional technologies require larger equipment,
Difficult to install on small automatic welding machines.

(Object of the Invention) The present invention solves the above-mentioned problems and provides a welding arc position control device that can be made smaller and lighter.

(Structure of the Invention) The present invention provides a photodetector comprising a pair of slits and a light-receiving element for detecting welding arc light or the shadow of a groove edge caused by reflection of the welding arc light on the inner surface of the groove, An amplifier that amplifies the output, a comparator that compares the output from the amplifier with the set voltage output from the reference voltage setter and outputs a digital signal, and calculates the digital signals from each comparator to generate a welding torch position control signal. A groove tracing control device for horizontal arc welding is characterized in that it comprises an operational amplifier that outputs an output signal, and a welding torch vertical movement mechanism that moves the welding torch position up and down using the output from the operational amplifier.

Below, regarding the groove tracing control device of the present invention,
An embodiment of horizontal electrogas welding will be described in detail based on the drawings.

FIG. 1 is a block diagram showing a groove tracing control device according to the present invention. Figure 2 shows a front view of the detector. As shown in FIGS. 1 and 2, the detector 1 has a pair of slits 4u and 4l opened symmetrically and parallel to the partition plate 3 on the light receiving side of a partition plate 3 provided inside the box. Consisting of light receiving elements 2u and 2l provided inside the box body facing the slit, the groove edge of the lower base material 10 is detected by welding arc light or reflected light from the groove of the welding arc through the slits 4u and 4l. The light-receiving elements 2u and 2l detect the shadow 14 produced in step 11 as light and dark.

The comparators 7u and 7l are connected to the light receiving elements 2u and 7l, respectively.
The voltage obtained by voltage amplifying the output from 2l with amplifiers 5u and 5l is compared with the reference voltage output from reference voltage setting devices 6u and 6l, respectively, and output as a digital signal of 1 or 0. .

The upper comparator 7u outputs a digital signal of 0 when the amount of light detected by the upper light receiving element 2u is large and the voltage amplified by the amplifier 5u is higher than the reference voltage output from the reference voltage setting device 6u. However, when the amount of light detected by the light receiving element 2u decreases and the output voltage becomes lower than the reference voltage, a digital signal of 1 is output.

On the other hand, the lower comparator 7l is connected to the lower light receiving element 2l.
When the amount of light detected by the amplifier 5l is small and the voltage amplified by the amplifier 5l is lower than the reference voltage output from the reference voltage setting device 6l, a digital signal of 0 is output.
When the amount of light detected by the light receiving element 2l increases and the output voltage becomes higher than the reference voltage, the digital signal becomes 1.
Output.

The operational amplifier 8 calculates the two digital signals output from the comparators 7u and 7l, and outputs a position control signal based on the calculation result, which is transmitted to the welding torch vertical movement mechanism 9. The welding torch moving mechanism 9 thereby moves the welding torch 15 up and down to control the conflicting position between the welding arc 13 and the lower base metal groove edge 11.

FIGS. 3 and 4 show a plan sectional view and a side view during lateral electrogas welding.

Detector 1 is 30mm by the detector vertical adjustment mechanism 20
Can be moved up and down. The sliding copper butt 21 is pressed against the upper and lower base materials 12, 20 by a pressing tool 22 of 5 to 15
It is being pushed by the power of Kgf. The vertical movement mechanism 9 of the welding arc position control section includes a torch clamp 1.
A welding torch 15, the detector vertical movement mechanism 20, and a sliding copper butt presser 22 are attached via the welding torch 15, the detector 1, and the sliding copper butt 21 are moved up and down by about 100 mm at the same time. It can be moved.

The gaps between the slits 4u and 4l of the detector 1 are each 0.2 mm, and the thickness of the partition plate 3 is 0.2 mm.

Install the welding machine on a fixed rail roughly parallel to the groove. The welding nozzle 19 is inserted into the groove surrounded by the upper and lower base metals 12, 10, the copper backing 23, and the sliding copper backing 21, and the tip 17 of the wire 16 is connected to the tip 17 of the wire 16 at a position of 35 to 50 mm from the tip of the nozzle. The welding torch 15 is set so that the groove edge 11 of the lower base material 10 is at a predetermined position. Next, the position of the detector 1 is adjusted by the detector vertical adjustment mechanism 20 so that the partition plate tip 25 is aligned with the wire tip 17 and the lower base material bevel edge 11.
Adjust the position so that it is on one plane, and then start welding. Simultaneously with the start of welding, a position control signal is given to the welding torch vertical movement mechanism 9.

5, 6, and 7 are diagrams showing the positional relationship among the arc 13, the lower base material groove edge 11, and the detector 1 during welding.

FIG. 5 is a diagram showing how the welding arc 13 and the detector 1 are in the correct positional relationship with respect to the lower base material groove edge 11. The tip 25 is on one plane, the upper slit 4u is located above the shadow 14 of the lower base material groove edge 11 due to the welding arc light, and the lower slit 4l is located within the shadow 14.

The upper light receiving element 2u detects the arc light and outputs it from the light receiving element 2u, but the signal voltage amplified by the amplifier 5u is higher than the reference voltage output from the reference voltage setting device 6u and is output from the comparator 7u as a digital signal. A signal of 0 is output. On the other hand, since the lower slit 4l is in the shadow 14, the amount of light detected by the light receiving element 2l is small, and the output voltage amplified by the amplifier 5l is higher than the reference voltage output from the reference voltage setting device 6l. is also low, and the comparator 7l outputs a digital signal of 0. The above two signals are calculated by the operational amplifier 8, and the calculation result becomes 0, no control signal is output to the welding torch vertical movement mechanism 9, and the welding arc does not move.

As shown in FIG. 6, when the welding arc 13 separates from the lower base metal groove edge 11, that is, the distance l between the welding arc point and the lower base metal groove edge 11 in the groove width direction increases by 4L. , the angle α between the lower base material surface and the shadow 14 becomes smaller, and the shadow 14 is lowered by Δlb/a at the tip of the detector 1 with respect to the lower base material groove edge 11. On the other hand, the detector 1 moves up by Δl together with the welding torch, and h=Δl(1+b/
a). At this time, a part of the lower slit 4l is exposed above the shadow 14, that is, h>0.2mm.
In this state, the amount of light detected by the lower light-receiving element 2l increases, the output voltage amplified by the amplifier 5l becomes higher than the reference voltage output from the reference voltage setter 6l, and the digital signal from the lower comparator 7l increases. signal 1
is output, and there is no change in the amount of light detected by the upper light receiving element 2u from the state shown in FIG.
A digital signal of 0 is output from. These two signals are operated on by an operational amplifier 8, and as a result, a falling signal is output. The descending signal is transmitted to the welding torch vertical movement mechanism 9, and the welding torch 15, detector 1, and sliding copper butt 21 move downward.

In Figure 7, the welding arc 13 is connected to the lower groove edge 11.
This figure shows a state in which the distance l becomes shorter by Δl as the distance l approaches .Contrary to the state shown in FIG. On the other hand, the shadow 14 has moved up by h=(1+b/a), and when h>0.2mm,
A part of the upper slit 3u enters the shadow 14, and the amount of light detected by the upper light receiving element 2u decreases, and the voltage output from the amplifier 5u decreases, becoming lower than the reference voltage output from the reference setting circuit 6u. The digital signal 1 is output from the comparator 7u. The lower light receiving element 2l is in the same state as shown in FIG. 5, a digital signal of 0 is output from the comparator 7l, these two signals are calculated by the operational amplifier 8, and as a result, a rising signal is output, and the welding torch This is transmitted to the vertical movement mechanism 9, and the welding torch 15, detector 1, and sliding copper dowel 21 move upward. Therefore, the welding arc 13 is always kept at a constant distance from the lower base metal groove edge 11 in the groove width direction.

Therefore, since Δl=ah/a+b, by making the horizontal distance a from the groove edge 11 to the welding arc 13 equal to the horizontal distance b to the detector 1, Δl>
The welding torch vertical movement mechanism 9 operates in the state of 0.1 mm.

(Effects) Since the present invention is configured as described above,
The detection unit has become extremely small and lightweight, and high-precision scanning control has become possible.

[Brief explanation of drawings]

Figure 1 is a block diagram of the groove tracing method of the present invention in horizontal electrogas welding, Figure 2 is a front view of the detector, and Figures 3 and 4 are cross-sectional planes showing horizontal electrogas welding. Figures and side views; Figure 5 is a state diagram showing the proper positional relationship of the welding arc, detector, and groove edge; Figures 6 and 7 are state diagrams showing the state in which the welding arc has deviated from its proper position. . 1...detector, 2u, 2l...light receiving element, 3...
...Partition plate, 4u, 4l...Slit, 5u, 5
l...Amplifier, 6u, 6l...Reference setting circuit, 7
u, 7l... Comparator, 8... Operational amplifier, 9...
Welding torch vertical movement mechanism, 10...Lower base material, 1
1... Bevel edge, 12... Upper base material, 13...
Welding arc, 14...Shadow caused by welding arc, 15
...Welding torch, 16...Welding wire, 17...
Wire tip, 18...Tooth clamp, 19...
Welding nozzle, 20...Detector vertical adjustment mechanism, 21
... Sliding copper stopper, 22 ... Pressing tool, 23 ...
Copper backing metal, 24... control circuit, 25... tip of partition plate, 26... servo motor, 27... welding metal, 28... spacer.

Claims (1)

[Claims] 1. In order to detect the shadow of the groove edge caused by the welding arc light or the reflected light of the welding arc light on the inner surface of the groove, a A photodetector consisting of a pair of parallel opening slits and a pair of light-receiving elements provided inside the box opposite to the slits, a pair of amplifiers for amplifying the output from the light-receiving elements, and an output from the amplifier. A pair of comparators that respectively compare the set voltages output from the reference voltage setter and output a digital signal, an operational amplifier that calculates the digital signal from each comparator and outputs a welding torch position control signal, and the calculation. A groove tracing control device for horizontal arc welding, comprising a welding torch vertical movement mechanism that vertically moves the position of a welding torch and the photodetector attached to a detector vertical adjustment mechanism using an output from an amplifier. .