JPS62244587A - Circumferential welding device for pipe and pipe plate by laser - Google Patents

Abstract

PURPOSE:To control profiling of a weld line with high accuracy and to permit high-quality welding with high efficiency by calculating and detecting the deviation of a welding head from the weld line from either of the inside circumference of a sensor position and the inside circumference of a pipe and feeding a correction signal to a driving device. CONSTITUTION:The output signals of two sensors 111, 112 on an x-axis are 111=0, 112=1 when the circumference of the sensor position and the inside circumference 9 of the pipe deviate. The result of the calculation 111-112<0 is then outputted and the welding head moves to the position 111-112=0 with the x-axis as a forward direction. The output signals of the two sensors 113, 114 on the y-axis are 113=1, 114=0 in said position and the result of the calculation 113-114>0 is outputted. The welding head moves on the y-axis to the position 113-114=0. The result of the calculation 111-112<0 is outputted in this position and the welding head moves on the x-axis to the position 111-112=0. The deviation between the circumference 10 of the sensor position and the inside circumference 9 of the pipe is thereby kept within an error range of the sensor 11. The positioning control is thus ended.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for automatically welding nine pipes and a tube sheet by laser welding.

[Conventional technology]

Conventionally, tube ends are inserted into multiple tube plate holes in a heat exchanger,
When automatically welding the outer circumference of the tube and the tube plate hole edge, TIG
Although an automatic NC welding machine using the welding method is used, fine adjustments to the welding position are made by the operator one by one.

However, attempts are being made to apply laser welding, which has recently been praised as a high-speed welding method, to welding tubes and tube sheets, but complete automation is desired in order to take advantage of its high efficiency. .

[Problem that the invention seeks to solve]

The present invention was proposed in view of these circumstances, and
The weld line between the outer periphery of the tube and the edge of the tube plate hole is automatically and accurately detected, and the laser welding head is positioned to point at the weld line accurately, thereby controlling highly accurate weld line tracing and achieving high efficiency. The purpose of the present invention is to provide a circumferential laser welding device for tubes and tube sheets that can perform high-quality welding.

[Means for solving problems]

To this end, the present invention provides a laser welding head that laser welds the welding line between the outer periphery of the tube and the edge of the tube plate hole while rotating around the central axis of the tube, and a drive that moves the laser welding head toward the welding line. a sensor head which is fixed near the center of the tube of the laser welding head and has position detection sensors arranged at four points equally spaced on the circumference on the circumference of the sensor position having the same diameter as the inner circumference of the tube; The drive device receives the signals from the four position detection sensors of the laser welding head, compares the signals of each two opposing sensors, and calculates and detects the deviation of the laser welding head from the welding line based on the deviation between the circumference of the sensor position and the inner circumference of the pipe. The invention is characterized by comprising an arithmetic and control device that sends correction signals to the computer.

[For production]

With the above configuration, the weld line between the outer periphery of the tube and the edge of the tube plate hole is automatically and accurately detected, and the laser welding head is accurately positioned to point there, thereby achieving highly accurate weld line tracing. It is possible to obtain a laser circumferential welding device for tubes and tube sheets that can be controlled and perform high-quality welding with high efficiency.

〔Example〕

One embodiment of the present invention will be explained with reference to the drawings. Fig. 1 shows the laser welding head part, Fig. 1(A) is a partially cutaway front view, Fig. 1(B) is a side view, and Fig. 1(C) is a partially cutaway front view. Plan view,
Fig. 2 is a system diagram of the welding line detection control device, Fig. 6 is a characteristic diagram of the pulse shaping circuit shown in Fig. 2, Fig. 4 is a flowchart of the welding line detection process by the arithmetic and control unit shown in Fig. 2, and Fig. 5 The figure is an explanatory diagram of a weld line detection mode according to FIG. 4.

First, in FIGS. 1 and 2, numeral 1 indicates a tube plate in which a plurality of tube plate holes 2 (one tube plate hole is shown) is bored, and 3 indicates the tube plate hole 2.
The weld line 4 between the outer periphery of the tube and the edge of the tube plate hole 2 is circumferentially welded. Reference numeral 5 denotes a laser transmission tube of a laser welding head that faces the welding line 4 while rotating around the central axis of the tube B, and a laser beam 7 is transmitted to a laser condenser lens 6 housed near the tip of the tube. Aim and irradiate the welding line 4.

Reference numeral 8 denotes a sensor head fixed to the center of the tube 3 of the laser transmission tube 5, and at its tip there are sensors located at four equally spaced points on the circumference 10 at the same diameter as the inner circumference 9 of the tube 3. A detection sensor 11 is arranged. In addition, four position detection sensors 11
The circumference at which the tube is placed can be adjusted according to the diameter of the target tube.

12 is a light emitting element such as a semiconductor laser or a light emitting diode that emits sensor light to each of the position detection sensors 11, and 13 is a light emitting fiber that sends the light from the light emitting element 12, and a light emitting condenser lens is attached to the tip of the light emitting fiber. 14 is installed. Reference numeral 15 denotes a light-receiving fiber arranged at the center of the light-emitting fiber 13, and a light-receiving and condensing lens 16 is attached to the tip thereof.

17 is a diaphragm located at the tip of the light receiving and condensing lens 16;
19 is a light-receiving element; 19 is a pulse shaping circuit that receives the output signal of the light-receiving element 18; 20 receives the output signal of the pulse shaping circuit 19, and compares the signals of the two opposing position detection sensors 11 to determine the sensor position. an arithmetic control device that calculates and detects the deviation of the axis of the laser welding head, that is, the laser transmission tube 5 from the welding line 4, based on the deviation between the circumference 10 and the pipe inner circumference 9;
Reference numeral 21 denotes a pulse motor which receives the output of the arithmetic and control unit 20 and moves the laser transmission tube 5 of the laser welding head, and the amount of movement is controlled by the number of pulses. 22 is a laser oscillator that receives the output of the arithmetic and control unit 20 and sends a welding laser to the laser transmission tube 5.

In such a device, "first, the position of the pipe 3 is memorized in advance by the arithmetic and control unit 20 using a well-known NC control method, and the pulse motor 21 is driven once based on the deviation, and the weld line 4 is
Laser welding head for laser transmission tube 5
perform rough positioning.

Next, the sensor head 804 position detection sensors 11
When the light from the light emitting element 12 is transmitted through the light emitting fiber 13 and condensed and irradiated onto the surface of the tube 6 by the light emitting condenser lens 14, the light reflected by the surface of the tube 3 is again emitted and condensed. Passes through the lens 14 and enters the receiving fiber 15,
After passing through this, the light is guided to the light receiving and condensing lens 16 to the aperture 17, and then sent to the light receiving element 18 where it is converted into an electrical signal.

The electrical signal output from the light-receiving element 18 is sent to a pulse shaping circuit 19, where the electrical signal shown in FIG. If there is any reflected light, an intensity of "1" is output, and if there is no reflected light, an intensity of "0" is output, which is sent to the arithmetic and control unit 20.

In the arithmetic and control unit 20 which receives the signals from the four position detection sensors 11, and in the pulse motor 21 which moves the laser welding head by the output thereof, the fourth
Accurate positioning of the laser welding head is performed by performing calculations and driving as shown in the flowchart shown in the figure, and FIG. 5 will also be described in detail below.

That is, in FIG. 5, four sensors 11 are installed on a circumference 10 having the same diameter as the inner circumference 9 of the tube 3, and each sensor 11 has a tube directly below it, as shown in FIG. The detection result is output from the pulse shaping circuit 19, and if the tube 3 exists, a signal "1" is output, and if the tube 3 does not exist, a signal "0" is output.

As shown in Figure 5 (A), if the sensor position circumference 10 and the inner circumference 9 of the tube are misaligned, the output signals of the two sensors 111 and 112 on the X axis will be 11 = 0. 11
When 2=1, a calculation result of 111-112<D is output, which causes the laser welding head to move in the positive direction on the X-axis.
Move at a position where 111-112 = 0, and move to the same position (B)
become that way.

At this position, the output signals of the two sensors 113 and 114 on the y-axis are 115=1, 114=O, and 115-1.
Since the calculation result 14>0 is output, this causes the laser welding head to move in the negative direction on the y-axis, 11. -1
14=0 and move to the position shown in the same figure (C).

At this position 111=0, 112=1 to 111-1
The calculation result of 12<0 is output, and the laser welding head moves in the positive direction on the X axis.11. -112-0, as shown in Figure (D).

In the same figure (D), the deviation between the sensor position circumference 10 and the inner circumference 9 of the tube is within the error range of the sensor 11, and the positioning control is completed.

The fact that the laser welding head has been accurately positioned in this way is transmitted from the arithmetic and control unit 20 to the laser oscillator 22, and the laser beam 7 is sent to the laser transmission tube 5 to start laser welding.

〔Effect of the invention〕

In short, according to the present invention, there is a laser welding head that laser welds the welding line between the outer periphery of the tube and the edge of the tube plate hole while rotating around the central axis of the tube, and a laser welding head that moves toward the welding line. a driving device; a sensor head fixed near the center of the tube of the laser welding head and having position detection sensors arranged at four points equally spaced on the circumference of the sensor position having the same diameter as the inner circumference of the tube; The sensor head receives signals from the four position detection sensors, compares the two opposing sensor signals, and calculates and detects the deviation of the laser welding head from the welding line based on the deviation between the circumference of the sensor position and the inner circumference of the pipe. Equipped with an arithmetic and control device that sends correction signals to the drive device, it automatically and accurately detects the weld line between the outer circumference of the tube and the edge of the tube plate hole, and positions the laser welding head to point there. The present invention is industrially extremely useful because it provides a circumferential laser welding device for tubes and tube sheets that can accurately perform welding, control highly accurate welding line tracing, and perform high-quality welding with high efficiency. It is something.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the laser welding head of the laser welding device for pipes and tube sheets according to the present invention, in which (A) is a partially cutaway front view, (B) is a side view, and ( C) is a plan view, Figure 2 is a system diagram of the weld line detection control device, Figure 3 is a characteristic diagram of the pulse shaping circuit in Figure 2, and Figure 4 is weld line detection by the arithmetic and control unit in Figure 2. Process flowchart, 5th
The figure is an explanatory diagram of a weld line detection mode according to FIG. 4. 1... Tube sheet, 2... Tube sheet hole, 6... Tube, 4.1,
Welding line, 5... Laser transmission tube, 6... Laser condensing lens, 7... Laser beam, 8... Sensor head, 9... Tube inner circumference, 10... Sensor position circumference, 11...Position detection sensor, 12...Light emitter,
13... Light emitting fiber, 14... Light emitting condensing lens, 15... Light receiving fiber, 16... Light receiving condensing lens, 17... Aperture, 18... Light receiving element, 19...
Pulse shaping circuit, 20... Arithmetic control unit, 21... Pulse motor 122... Racer oscillator. Sub-Agent Patent Attorney Masa Tsukamoto Figure 2 Figure 3 (A) 11t4jz<o: li to zglaze Er3M! 2
(D) 5th drawing (B) Guy, -ti-・0

Claims (1)

[Claims] A laser welding head that laser welds the weld line between the outer periphery of the tube and the edge of the tube plate hole while rotating around the central axis of the tube, a drive device that moves the laser welding head toward the weld line, and the laser welding described above. The sensor head is fixed near the center of the tube and has the same diameter as the inner circumference of the tube.The sensor head has position detection sensors arranged at four points equally spaced on the circumference, and the four positions of the sensor head. Receiving the signal from the detection sensor, comparing the signals of two opposing sensors, calculating the deviation of the laser welding head from the welding line from the deviation between the sensor position circumference and the pipe inner circumference, and sending a correction signal to the drive device. A circumferential laser welding device for a tube and a tube sheet, characterized by comprising a control device.