JPH054940Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to a welding device for welding a corrugated pipe whose outer circumferential surface is formed into a corrugated shape, and in particular, which performs arc welding on the outer circumferential surface of a corrugated pipe whose outer circumferential surface is formed into a corrugated shape. It is related to the device.

BACKGROUND OF THE INVENTION It is well known that corrugated pipes having a corrugated outer circumferential surface are used as coatings for various wire conditions and as containers for heat pipes. When using a corrugated tube as a heat pipe container, it is necessary to cut the corrugated tube to a predetermined length and seal it by attaching a cap to the open end. The outer circumferential shape of the cross section perpendicular to the corrugated pipe is eccentric with respect to the axis of the corrugated pipe, and the outer circumferential shape of the cross section is a special circular shape that deviates from a perfect circle. Therefore, the shape of the opening end is also a perfect circle. However, it is eccentric to the axis of the corrugated pipe, and therefore there are many difficulties in fitting a hat-shaped cross-section cap with a flange formed on the outer periphery of the recess into the open end of the corrugated pipe. For this purpose, for example, as shown in FIG. 3, the end 2 of a corrugated pipe 1 is formed into a straight pipe by plastic working, and then a cap 3 with a hat-shaped cross section is formed.
were fitted together, and a weld 4 was applied to the outer periphery.

However, when the end portion 2 of the corrugated pipe 1 is plastically deformed into a straight pipe shape, there is a problem in that stress corrosion cracking occurs subsequently because internal stress remains. Therefore, conventionally, as shown in FIG. 4, by using a cap 7 in which the recess 5 and the flange 6 are eccentric by a predetermined dimension e similar to the opening of the corrugated pipe 1, the opening end of the corrugated pipe 1 is specially machined. The end of the corrugated pipe 1 is hermetically sealed by fitting the cap 7 without applying a cap 7 and welding 8 around its outer periphery.

Problems to be Solved by the Invention However, when using the cap 7 in which the recess 5 and the flange 6 are eccentric, there is no need to perform plastic working on the open end of the corrugated pipe 1, so stress corrosion due to residual stress is avoided. Although there were no problems such as cracks, the shape of the open end to be welded was not a perfect circle and was eccentric to the axis of the corrugated pipe 1, so welding was performed while rotating the corrugated pipe 1. In the case of arc welding, the distance between the welding electrode and the outer circumferential surface of the corrugated pipe changes, causing problems such as the arc becoming unstable. Welding was carried out manually without obtaining
There were problems with poor workability and high costs.

This idea was made against the background of the above-mentioned circumstances, and it is a method to automatically and stably weld the outer periphery of a corrugated pipe whose cross section is not a perfect circle but whose cross section is eccentric with respect to its axis. The purpose of this invention is to provide a welding device that can perform the following steps.

Means for Solving the Problems In order to achieve the above object, this invention has a main shaft that rotates while gripping a corrugated pipe with its tip protruding, and an outer circumference of the corrugated pipe held by the main shaft. A torch that holds a welding electrode facing a surface, a slide mechanism that moves the torch back and forth in the radial direction of the corrugated pipe, and a change in voltage between the welding electrode and the outer peripheral surface of the corrugated pipe during arc welding. Therefore, there is a measuring device that detects changes in the distance therebetween, and a controller that drives the slide mechanism to maintain the distance between the welding electrode and the outer peripheral surface of the corrugated pipe at a constant dimension based on the signal obtained from the measuring device. The present invention is characterized by having a configuration including the following.

Function: In the device of this invention, the corrugated pipe, which is the object to be welded, is gripped by the main shaft with its tip protruding. An arc is generated between the corrugated tube and a welding electrode held by a torch, and in this state the corrugated tube is rotated by the main shaft to weld the entire outer circumference of the corrugated tube. In that case, as the corrugated pipe rotates, the distance between its outer circumferential surface and the welding electrode changes, and the change in distance corresponds to the change in voltage between the welding electrode and the corrugated pipe outer circumferential surface during welding, that is, the welding voltage. A change in is detected by the measuring instrument and an output signal is sent to the controller, and the controller drives the slide mechanism based on the input signal. As a result, the torch is moved back and forth with respect to the outer circumferential surface of the corrugated pipe, the distance between the welding electrode and the corrugated pipe is maintained constant, and stable welding is performed.

Embodiment Next, an embodiment of this invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of this invention, in which a main shaft 10 for gripping a corrugated pipe 1, which is an object to be welded, is provided within a main shaft head 11.
As shown in FIG. 4, this corrugated pipe 1 has a cap 7 fitted into the opening at the tip, with the center of the recess 5 aligned with the axis, and the flange 6 offset by a predetermined distance e with respect to the recess 5. The spindle 1
0 is configured to pass through this corrugated pipe 1 so that its tip protrudes forward, and to be held in this state by a chuck 12. This main shaft 1
0 is connected to a drive motor inside the spindle head 11 via a gear mechanism (not shown), and a mechanism (not shown) for opening and closing the chuck 12 is provided inside the spindle head 11. Note that the drive motor, gear mechanism, and mechanism for opening and closing the chuck 12 may be those employed in machine tools such as lathes.

A column 14 is erected on a base 13 provided on the front side of the spindle head 11, and a slide mechanism 15 is formed in front of the column 14. This slide mechanism 15 is for vertically moving a slider 16, and has a guide rail 17 formed along the vertical direction on the front of the column 14, and a feed screw shaft 18 attached parallel to the guide rail 17. The slide 16 is engaged with these guide rails 17 and the feed screw shaft 18. The feed screw shaft 18 is connected to the servo motor 19, and therefore the slider 16 is connected to the servo motor 19.
By rotating it, you can move it up and down. The slider 16 also has a welding electrode 20
A torch 21 is held pointing toward the tip of the corrugated pipe 1.

Furthermore, a corrugated pipe 1 is placed on the bed 13.
A cap holder 22 is disposed coaxially with the main shaft 10 to prevent the cap 7 fitted therein from falling off. This cap holder 22 is made of, for example, an air cylinder, and has a head 2 that fits into the recess 5 of the cap 7 at the tip of the rod 23.
4 is rotatably attached.

The torch 21 is used to perform arc welding on the outer periphery of the tip of the corrugated pipe 1, and is provided with a measuring device 25 for detecting the distance between the welding electrode 20 and the corrugated pipe 1. This measuring device 25
is composed of a detector that detects the voltage between the welding electrode 20 and the corrugated pipe 1 and outputs a signal, and this measuring device 25 is controlled by the control system as shown in the control system diagram in FIG. The servo motor 19 is also connected to the controller 26. When the voltage obtained by the measuring device 25 becomes higher than a predetermined reference voltage, the servo motor 19 is rotated to move the slider 16
By lowering the welding electrode 20, the welding electrode 20 approaches the corrugated pipe 1. Conversely, when the detected voltage becomes lower than the reference voltage, the servo motor 19 is moved in the opposite direction to the above case. By rotating and raising the slider 16, the welding electrode 20 is separated from the corrugated pipe 1.

Welding of the cap 7 to the corrugated pipe 1 using the above-mentioned apparatus is performed in the following manner.
That is, the corrugated pipe 1 passes through the main shaft 10 and is gripped by the chuck 12 so that its distal end protrudes, and the cap 7 is fitted into the distal end of the corrugated pipe 1 in this state. As the rod 23 of the cap holder 22 extends, the cap 7 is held down by the head 24 attached to its tip, and at the same time, the axial center of the cap holder 22 and the main shaft 1
By aligning with the axis of the corrugated pipe 1, the deflection of the tip of the corrugated pipe 1 is corrected. The torch 21 is held toward the outer periphery of the cap 7 in this state, the distance between the welding electrode 20 and the cap 7 is set to a predetermined dimension, and the corrugated pipe 1 is rotated together with the main shaft 10 to perform arc welding. Let's do it. In that case, since the tip opening of the corrugated pipe 1 is eccentric with respect to the axis of the corrugated pipe 1 and has a special circular shape that deviates from a perfect circle, the outer periphery to be welded is on the axis of the corrugated pipe 1. The welding electrode 2 will swing around in relation to the heart.
The distance from 0 changes. This distance variation is detected by the measuring device 25 as a voltage change,
The controller 2 is controlled by the output signal from the measuring device 25.
6 rotates the servo motor 19 forward and backward, so the torch 21 moves up and down together with the slider 16 following the eccentric rotational movement of the tip of the corrugated pipe 1. That is, since the distance between the welding electrode 20 and the corrugated pipe 1 is maintained at a predetermined constant distance, the arc is stabilized and good welding is performed.

Effects of the invention As is clear from the above explanation, according to the device of this invention, when welding the outer circumference of a corrugated pipe while rotating it around its axis, it is possible to Since the welding electrode can be moved to follow the whirling motion, it is possible to automate welding, stabilize the arc, and perform good welding. Since there is no need to process the section into a straight tube shape, workability is good, and excellent practical effects can be obtained, such as being able to prevent problems such as stress corrosion cracking due to residual stress. Furthermore, the device of this invention detects the variation in the distance between the welding electrode and the outer peripheral surface of the corrugated pipe due to the variation of the welding voltage during welding, and adjusts the welding electrode to maintain the distance constant. , it is not necessary to detect the fluctuation of the welding position during one rotation of the corrugated tube before welding starts, so there is no particular loss of welding work efficiency, and the distance measurement sensor etc. It is not necessary to separately provide a sensor near the welding electrode, and therefore the equipment cost is low, and there is also the advantage that there is no risk of sensor etc. being damaged due to sparks or flux scattering during welding.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing one embodiment of this invention, Fig. 2 is its control system diagram, Fig. 3 is a partial cross-sectional view showing an example of a tube end sealing structure of a corrugated pipe, and Fig. 4 is a diagram showing another example of the tube end sealing structure of a corrugated pipe. It is a partial sectional view showing a tube end sealing structure. 1... Corrugated pipe, 7... Cap, 8...
Welding, 10...Main shaft, 15...Slide mechanism, 1
6...Slider, 17...Guide rail, 18...
...Feed screw shaft, 19...Servo motor, 20...
Welding electrode, 21...torch, 25...measuring device, 2
6...Controller.

Claims (1)

[Scope of utility model registration request] A main shaft that rotates while gripping a corrugated pipe with its tip protruding; a torch that holds a welding electrode toward the outer circumferential surface of the corrugated pipe held by the main shaft; a slide mechanism that moves back and forth in the direction; a measuring device that detects changes in the distance between the welding electrode and the outer peripheral surface of the corrugated pipe due to changes in voltage between the welding electrode and the outer peripheral surface of the corrugated pipe during arc welding; A welding device for the outer periphery of a corrugated pipe, comprising a controller that drives the slide mechanism to maintain a constant distance between the welding electrode and the outer periphery of the corrugated pipe based on a signal.