JPH1094889A - Piping laser beam welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further automatize a welding equipment and to make it highly efficient in all positioned welding of a thin walled piping with using a laser beam machine. SOLUTION: A laser beam welding means 6 and position detection means 7, 8 are arranged to a rotation drive means 2 aligned to the center axis of a piping 1 fixed by a pair of piping fixing means 3, 3, after position recognition of a butted weld joint part is conducted, when welding, while driving a position control mechanism and the rotation drive means 2 based on the position information and conducting joint welding with the laser beam welding means 6, precise welding is made possible to improve operability and functionability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding apparatus suitably applied to automatic welding of thin pipes, and more particularly to a welding apparatus for thin pipes using laser welding means.

[0002]

2. Description of the Related Art Hitherto, automatic welding of pipes in all positions using a YAG laser has not been put to practical use. As shown in FIG. 9, for welding thin pipes, a C-shaped rotating wheel 58 is rotatably housed in a U-shaped opening of a torch driving device 53, and a TIG welding torch 52 is provided on the inner peripheral side of the C-shaped rotating wheel 58. After the pipe 1 is disposed on the center of the C-shaped rotating wheel 52, the C-shaped rotating wheel 52 is rotated, and the pipe 1 is welded in all positions.

[0003] Further, in pipe welding using a laser, FIG.
0, the center of the chuck portion 56a of the positioner 56 is aligned with the center axis of the chuck, and the pipe 1 is gripped, while the optical axis of the laser beam condensing lens 54 is aligned in a direction perpendicular to the center axis of the pipe 1. There is a case where the pipe 1 is welded by irradiating the laser beam 55 downward while rotating the pipe 1.

[0004]

In the nuclear power plant industry, 90% of pipes used in uranium reprocessing plants are thin pipes of up to 3 to 4 mm.
There are five times as many welds as pipes used in a WR (pressurized water reactor) plant, and the welding work becomes extremely complicated. For this reason, at present, thin-walled pipes are welded using the all-position welding apparatus for TIG welding shown in FIG. 9 described above. However, in TIG welding, the necessity of beveling of the weld joint and the input of welding heat are reduced. Since it is large, it is now a step forward in terms of high efficiency due to measures for preventing thermal deformation and the limit of shortening the welding time. Therefore, there has been a strong demand for higher efficiency in a pipe welding apparatus used in the reprocessing plant.

In order to solve such a problem, the present invention has focused on a laser welding machine. Laser welding machines, especially YAG laser welding, can perform one-pass welding by optical fiber transmission of laser light.
High energy density enables high-speed welding with little thermal deformation, and at the same time, excellent operability enables multi-plating as shown in FIG. 7, for example, which is relatively easy compared to the conventional method. The welding time is shortened. In addition, YAG laser welding has a practical problem in welding thick pipes, but is suitable for welding thin pipes. SUMMARY OF THE INVENTION It is an object of the present invention to provide a welding apparatus which achieves further automation and higher efficiency in welding thin pipes using a laser welding machine.

[0006]

In order to achieve the above object, a first aspect of the present invention relates to a welding apparatus for a thin-walled pipe using a laser welding means. A pipe fixing means for fixing the pipe so that the pipe centers are aligned with each other, and a rotation driving means for rotating a welding joint position of the pipe fixed by the pipe fixing means,
A laser welding unit and a position detection unit disposed on one side of the rotation driving unit; a rotation control unit; and a position control mechanism interposed between the laser welding unit and the position detection unit (positioning mechanism). Comprising, while rotating and moving on the butt welding joint portion of the pipe by the rotation drive means, recognizes the position of the pipe by the position detection means and stores it as position information,
At the time of welding, a position control mechanism is driven based on the position information, and the laser is irradiated from a laser welding means (hereinafter referred to as a processing optical system) while welding is performed while re-driving the rotation drive means. .

In this case, it is preferable that a vibration control mechanism is provided on the other side of the rotation driving means so as to be able to suppress eyesight loss due to rotational vibration of the rotation driving section. According to a third aspect of the present invention, control of the rotational position of the rotary drive means is performed using a dual control system in which output position control by a stepping motor and confirmation and correction by an encoder or other rotational angle detecting means are performed. Good.

In this apparatus, since the processing optical system and the position detecting means (positioning mechanism) are arranged on one side of the rotation driving means in which the central axes of the pipes fixed by the pair of pipe fixing means are aligned, the laser is used. After performing position recognition of the butt weld joint part, which is indispensable for welding, the position control mechanism is driven based on the position information at the time of welding, and then the rotation driving means is re-driven while the processing optical system is used. By performing the joint welding, it is possible to perform accurate welding for preventing the focused spot diameter (approximately 0.4 mm) from slipping out, and to improve operability and functionality. Further, since the present invention provides a vibration control mechanism on the other side of the rotation drive means, it is possible to control or suppress minute vibrations generated during high-speed rotation of the rotation drive system for securing all postures, Thus, it is possible to improve the functionality by coping with the prevention of minute gaps. In addition, by controlling the rotation position of the rotation drive means using a dual control system in which output position control by a stepping motor and confirmation and correction by an encoder or other rotation angle detection means are performed, rotation, focus position, and axial direction are controlled. Simultaneous control of three axes becomes possible, which leads to further improvement in accuracy. In addition, the pipe fixing device is a manually-actuated electric pipe fixing device as shown in the embodiment described later, which inserts and fixes the pipe from both sides of the welding device from one direction and uses the above-described sensing mechanism to confirm the position, so that the laser is used. Workability of the entire device, including operation,
The problem was solved by improving the operability.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only. FIG. 1 shows an automatic welding apparatus for thin pipes using a YAG laser according to an embodiment of the present invention. 2
Reference numeral 0 denotes a common support plate (bottom plate), which is a base of the welding drive unit 2 to which a processing optical system 6 including a YAG laser and a positioning / detection mechanism including a semiconductor laser 7 and a CCD camera 8 are mounted, and the welding drive unit. The bases of the pipe fixing devices 3 and 3 which are arranged on both sides of the pipe 2 and support and fix the pipe 1 are fixed to the common support plate 20 respectively. A laser oscillator 4 is connected to the processing optical system 6 via an optical fiber cable 5, a semiconductor laser 7 and a CCD camera 8 are connected to a personal computer 18 via cables, and various motors for driving the processing optical system 6. Are connected to a drive control panel 17, and the drive systems of the pipe fixing devices 3, 3 are connected to the control panel 1 via cables.
9 are connected to each other, and a predetermined drive control described later is performed.

This device is fixed to a pipe 1 by a pair of pipe fixing devices 3 located on both sides of a welding drive device 2 with the welding drive device 2 interposed therebetween, and transmits a laser beam oscillated by a laser oscillator 4 through an optical fiber 5 to be processed. After converging with the optical system 6, the pipe 1 is irradiated to the butt-welding joint to cause fusion welding, and at the same time, the working optical system 6 is rotated by the welding drive unit 2 to perform full-circumferential welding. As shown in FIG. 2, the welding drive unit 2 includes a rotation drive system 2b including a C-shaped sub-rotator 2a,
A processing optical system 6 and positioning systems 7 and 8 are mounted on the upper surface of the C-type driven rotating body 2a, and are configured to be rotatable concentrically with the pipe 1 via positioning (detection) systems 7 and 8. Alignment mechanisms 33 and 34 are continuously provided on the lower surface of the mold slave rotor 2a.

The positioning / detection mechanisms 7 and 8 comprising the semiconductor laser 7 and the CCD camera 8 are a Z-axis positioning motor 13
And is mounted on a Z-axis slide plate 14 which can be slid in the Z-axis direction. The processing optical system is mounted on another positioning Z-axis slide 10 located on the opposite side of the positioning / detection mechanisms 7 and 8 with the pipe 1 interposed therebetween.
It is similar to the slide plate 14 in that the Z-axis positioning motor 9 is configured to be slidable in the Z-axis direction. Further, each of the Z-axis slide plates 10 and 14 slides on the lower surface side by the axis motors 11 and 15.
The shaft slide plates 12 and 16 are located. As a result, both the processing optical system and the positioning mechanism are slid in the two axes of the Χ-Z direction, and the centering can be easily performed.

According to such a configuration, after the pipe 1 is fixed by the pipe fixing devices 3 and 3, in order to detect the position of the butt joint portion of the pipe 1, the position setting and the axis slide 16 are performed while irradiating the semiconductor laser 7. After recognizing the intensity and shape of the reflected light of the semiconductor laser 7 with the axis positioning motor 15 with a coaxial encoder, the butt joint is positioned at the center of the vibration amplitude. The encoder signal of the position is stored in the personal computer 18 as the butting position. Then, a step count is performed for each rotation position, the entire circumference is detected, and the data is stored in the personal computer 18. At this time, the intensity and shape (especially dimensions) of the reflected light of the semiconductor laser 7 at a predetermined distance are input in advance in order to confirm the focal position of the YAG laser light and correct the focal length, and follow the approximate value. Then, the encoder signal of the Z-axis positioning motor (with a coaxial encoder) 13 is stored as data. A semiconductor laser 7 having a wavelength in the visible light range is used for these, and the reflected light is detected by a CCD camera 8. The positioning of the pipe 1 is detected for each pipe set 1, and the data obtained by this is used as an encoder signal from the personal computer 18 for each welding, and the focal length correction is performed in accordance with Z.
Positioning Z-axis slide 1 via axis positioning motor 9
0 is transmitted to the processing optical system 6. The misalignment correction is transmitted to the processing optical system 6 with the positioning Χ-axis slide 12 via the Χ-axis positioning motor 11, thereby contributing to high-precision welding.

As shown in FIGS. 3 and 4, the C-shaped slave rotor 2a has an upper casing 30 having a built-in rotary drive system 2b.
And the lower casing 3 in which the alignment mechanisms 33 and 34 are incorporated.
6 which are notched and open on one side in the circumferential direction.
Form, match the inner diameter, the outer diameter is the upper casing 3
0 is set concentrically larger than the lower casing 36, and the upper casing 30 is widened in a rectangular shape on the side opposite to the notch opening, and accommodates the rotation drive mechanism 70 of the C-shaped driven rotor 2 a. The C-shaped sub-rotating body 2a has a C-shaped ring shape in which a part in the circumferential direction is cut out in order to insert the pipe 1 in the rotation direction. 3
A ring-shaped C-shaped rail 32 having a large diameter and a diameter larger than that of the C-shaped rail 32 are vertically arranged in parallel to each other, and a rotation support cylinder 33 extending from the lower surface of the C-shaped rail 32 toward the lower casing 36 is connected. You. The rotation driving mechanism 70 of the C-shaped sub-rotating body 2a housed in the rectangular widened portion of the upper casing 30 includes a driving motor 21, a motor gear 22, a pulley interlocking gear 23, a timing belt 24, a pair of It consists of a driven gear 25, an intermediate pulley 28, and a belt presser 29,
Around the C-shaped gear 31 and the C-shaped rail 32, a plurality of gears with holding rollers are disposed.
And the C-shaped rail 32 so as to be able to rotate therewith. Further, the encoder 26 is meshed with the C-shaped gear 31 so that the rotational angle position can be easily detected. In addition, 3 in the figure
7 is a casing upper lid, 38 is a decorative lid, and 39 is a casing lower lid.

According to the C-type driven rotator 2a constituting the rotary drive system 2b, the rotation of the drive motor 21 is transmitted via the motor gear 22 to the pulley interlocking gear 23 which is driven by the gear and transmitted by the pulley. From here, it is transmitted to the driven gear 25 by the timing belt 24. And this C
In the mold follower 2a, the C-shaped gear 31, the C-shaped rail 32, and the rotation support cylinder 33 rotate integrally, and the rotation transmitted from the drive motor 21 via the timing belt 24 is disposed at a relative position. Since the power is transmitted to the C-type gear 31 through a pair of driven gears 25 via a pulley interlocking gear 23 which is driven by a pulley and transmitted by a gear, even if one driven gear 25 is in the notch, the other driven gear 25 Functions to maintain rotation. These sub-rotating bodies 2a are supported by a C-shaped rail 32 arranged coaxially with a C-shaped gear 31 by a holding roller gear 27 comprising a holding V-groove roller and a follow gear.

The driving motor 21 is a stepping motor.
And a stepping motor 21 for controlling the rotational position.
A double check function that sends a detection signal from an encoder 26 disposed on one side to the personal computer 18 and performs a predetermined calculation, and performs feedback control of a confirmation value on the drive control panel 17 side based on the calculation result. Therefore, as a rotary drive system for laser butt welding, rotational accuracy, positioning accuracy, etc., and operability and workability are improved.

Rotational accuracy in the case of laser butt welding is as follows.
Although it depends on the collective spot diameter, it is generally less than の of the spot diameter, and the accuracy range of 0.15 mm is usually used for the spot diameter of 0.3 mmΦ. For this, this accuracy is an important point. Therefore, in order to improve mechanical rigidity and cope with vibration during rotation transmission, a rotation support cylinder 33 is attached to the lower surface side of the C-shaped rail 32, and the peripheral surface of the centering roller 34 pivotally supported by the lower casing 36 at the tip end. The rigidity is increased by the two-point support of the centering roller 34 and the holding V-groove roller of the holding roller gear 27, and the rotation unevenness is suppressed by the centering of the centering roller 34. Cylinder 3
Vibration was suppressed by pushing the vibration control plate 35 made of a wear-resistant polymer material disposed between the three against the outer surface of the rotation support cylinder 33, thereby improving the rotation accuracy.

In performing the above-described high-precision and high-efficiency welding, fixing the pipe 1 becomes a problem.
As shown in FIG. 5, two pawls open and one pawl uses a pair of push-moving type pipe fixing devices 3. As shown in FIGS. 5 (A) and 5 (B), the pipe fixing device 3 has a casing 3a with a cutout 3a1 at a part in the longitudinal direction, and a C-shaped ring through which the pipe 1 can be inserted into the center position through the cutout 3a1. And an electric motor on the opposite side of the notch of the casing 3a.
An extruding mechanism 47 that can move forward and backward along the horizontal center line of the casing by a tab 46 is fixedly provided. At the tip of the piston of the pushing mechanism 47, a substantially trapezoidal push claw 45 having a V-shaped concave top is provided. At a vertically symmetric position on the vertical center line of the casing 3a, a support shaft 42 for rotatably supporting the upper claw 40 and the lower claw 41 is provided, and springs 44, 44 interposed on the support shaft 42 are provided. The hook-shaped portions 40a, 41a on the front side (notch side of the casing) of the upper claw 40 and the lower claw 41 can be expanded in the notch opening direction by the urging force. The base of the upper and lower claws 40 and 41 has a tongue piece extending toward the push claw, and guide rollers 43a and 43b at the ends thereof.
Is supported.

The pipe fixing device 3 includes the welding drive device 2
And the center axis is the same, it is disposed on both sides thereof, and the fixing of the pipe 1 in the device is shown in FIGS.
This is performed in the order of (C). First, in FIG. 6 (A), the hook-shaped portions on the front sides (the cutout side of the casing) of the upper and lower claws 40 and 41 are expanded in the cutout opening direction by the urging force of the spring 44, and the cutouts are opened. I do. When the pipe 1 is pushed in the direction shown by the arrow 48 from the notch opening in this state, the upper and lower pawl guide rollers 43a and 43b
6A is moved from FIG. 6A to FIG. 6B while being rotationally moved in the direction of the arrow 50 against the urging force of the pipe 1, the pipe 1 is inserted into the V-shaped groove at the top of the push claw 45. To reach.
At this time, the upper pawl 40 and the lower pawl 41 guide rollers 43a, 43b
The gap between the top and bottom claws 40 and 41 of the upper and lower pawls 40 and 41 is opposite to that of the upper and lower pawls 40a. The opening 3a1 is rotated and closed in the closing direction. 4
9a indicates the upper nail moving direction, and 49b indicates the lower nail moving direction.

Next, as shown in FIG.
The pushing mechanism 47 is activated by the tapper 46 to advance the piston to the center side, and the pipe 1 in contact with the top of the pushing claw 45 is pushed 51 toward the center shaft side, whereby the upper and lower pawl guide rollers 4 are pushed.
The upper claws 40a and 41a of the upper and lower claws 40 and 41a are completely closed via the support shaft 42 while intersecting with each other. The pipe 1 is fixed at the center axis position by the three-point support of the lower pawl 41, the lower pawl 41 and the pressing pawl 45.

Therefore, according to such an apparatus, if the pipe 1 is within the allowable dimensions, it can be fixed coaxially.
When the pipe 1 reaches the V-shaped groove at the top of the push claw 45, the pipe 1 is detected by a pressure detection sensor or the like disposed in the pushing mechanism, and is linked with the ON / OFF switch of the electric motor 46 by this detection signal. It is possible to construct a system that can automatically start the pushing mechanism 47 when the pipe 1 reaches the position of the push claw 45, thereby promoting automation and improving workability. Also in this pipe fixing device 3, the casing has a C-ring shape with a part cut off in the circumferential direction in order to secure the area along with the opening of the upper claw 40 and the lower claw 41 together with the mountability of the pipe 1. Is good.

It is the detection of the butt joint position that maximizes the construction of the rotary drive system 2b and the pipe fixing device 3. In the detection method, when the butt joint is an I-shaped groove, since it is difficult to position the joint, as shown in FIG. 8, a thread chamfer 1a1 is applied to the joint end surface 1a on the outer peripheral surface of the pipe 1 to form a small V-shaped groove. Is formed. The groove is irradiated with the convergent light of the semiconductor laser 7, the reflected light is photographed by the CCD camera 8, and the reflection intensity and shape are sent to the personal computer 18 as a video signal, and the personal computer 18 processes the image data into dimensions and intensity. A point having a strong strength and a recognized shape point having a small size are followed, and the position data is transferred to the coaxial encoder 13a of the Z-axis positioning motor 13 and the .DELTA.-axis positioning motor 15.
Is recognized and stored as a signal of the coaxial encoder 15a.

These are Z-axis / Χ-axis positioning motor 1
3, 15 and the reciprocating movement of a predetermined range by the detecting and moving mechanism composed of the axis slides 14, 16 and the rotation of the rotary drive system 2b and the data operation value from the position signal are also calculated. Import as axis position data. At the time of welding, the position data signal is sent to the Z-axis positioning motor 9 and the Χ-axis positioning motor 11 on the positioning side, and the rotation is reproduced and the position is reproduced to perform automatic centering, thereby improving work efficiency. Was planned. In this way, a highly efficient welding method was established.

As shown in FIG. 7, a plurality of main welding devices are arranged as a set of the rotary drive mechanism 2 and the pipe fixing devices 3 and 3 to perform a multi-operation, thereby achieving an unprecedented high efficiency. High-efficiency and high-precision welding of the thin-walled pipe 1 has become possible. In the drawing, reference numeral 57 denotes a laser beam branching device for sequentially branching laser light transmitted from one laser oscillator 4 to a predetermined position.

[0024]

As described above, according to the pipe YAG laser automatic welding apparatus of the present invention, extremely high precision and high efficiency can be achieved as compared with the conventional method of welding thin-walled pipes. Of material handling equipment such as moving
Full automation is possible and extremely useful in industry.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a welding device according to an embodiment of the present invention.

FIG. 2 is a detailed view of a welding drive unit of the welding apparatus shown in FIG. 1, (A) is a plan view, and (B) is a front view.

3A and 3B show an internal structure of a welding drive unit of the welding apparatus shown in FIG. 1, wherein FIG. 3A is a plan view, FIG. 3B is a front view, and FIG.

FIG. 4 is an enlarged view of a main part of the front view of the welding drive unit shown in FIG. 3;

5 shows a detailed view of a pipe fixing device of the welding device shown in FIG. 1, (A) is a plan view, and (B) is a front view.

6 is an operation explanatory view of the pipe fixing device shown in FIG. 5,
(A) is a state in which the pipe is in contact with the guide rollers of the lower and upper claws, (B) is a state in which the pipe is in contact with the V-groove of the push nail, (C)
Indicates a state where the pipe is pushed back to the center position and set.

FIG. 7 is a plan view showing a situation where a plurality of main welding devices are arranged to perform multi-operation.

FIG. 8 is a schematic diagram showing a method of detecting a butt joint position.

FIG. 9 is an overall configuration diagram of a welding device based on TIG welding according to a conventional example.

FIG. 10 is a front view of a laser welding situation according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pipe 1a Joint end surface 1a1 Thread chamfering 2 Welding drive device 2a C-type follower 2b Rotation drive system 3 Pipe fixing device 3a Casing 3a1 Notch 4 Laser oscillator 5 Optical fiber 6 Processing optical system 7 Semiconductor laser 8 CCD camera 9 Z axis positioning Motor 10 Positioning Z-axis slide 11 ΧAxis positioning motor 12 PositioningΧAxis slide 13 Z-axis positioning motor 13a Z-axis encoder 14 Positioning Z-axis slide 15 ΧAxis positioning motor 15a ΧAxis encoder 16 position Extension shaft slide 17 Drive control panel 18 Personal computer 19 Control panel 20 Bottom plate 21 Drive motor 22 Motor gear 23 Pulley interlocking gear 24 Timing belt 25 Follower gear 26 Encoder 27 Gear with holding roller 28 Intermediate pulley 29 Belt holder 30 Upper casing 31 Mold gear 32 C-shaped rail 33 Rotation support cylinder 34 Alignment roller 35 Vibration control plate 36 Lower casing 37 Casing upper lid 38 Decorative lid 39 Casing lower lid 40 Upper nail 40a, 41b Hook 41 Lower nail 42 Support shaft 43a Upper nail guide Roller 43b Lower claw guide roller 44 Spring 45 Push claw 46 Electric motor 47 Push mechanism 48 Pipe pushing direction 49a Upper claw moving direction 49b Lower claw moving direction 50 Roller moving direction 51 Pushing direction 52 TIG welding torch 53 Torch driving device 54 Lens 55 laser beam 56 positioner 56a chuck section 57 laser beam branching device 58 C-type rotating wheel 70 rotation driving mechanism

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B23K 37/053 B23K 37/053 A (72) Inventor Koji Fujiyoshi 1-1-1, Wadazakicho, Hyogo-ku, Kobe-shi Inside Kobe Shipyard Co., Ltd. (72) Inventor Masatoshi Tomita 1-1-1 Wadazakicho, Hyogo-ku, Kobe City

Claims (3)

[Claims] 1. A welding apparatus for a thin-walled pipe using a laser welding means, a pipe fixing means for fixing the pipe so that the center of the pipe coincides on both sides of a butt welding joint position of the pipe, and the pipe fixing means. Rotation driving means for rotating a welding joint position of the pipe fixed by: a laser welding means and a position detection means disposed on one side of the rotation driving means; a rotation driving means; a laser welding means and position detection. And a position control mechanism respectively interposed between the means, and after rotating and moving on the butt welding joint portion of the pipe by the rotation driving means, the position of the pipe is recognized by the position detection means and stored as position information, After the position control mechanism is driven based on the position information, the laser is irradiated from the laser welding means to perform welding while re-driving the rotation driving means. Apparatus. 2. The piping laser welding apparatus according to claim 1, wherein a vibration control mechanism is provided on the other side of said rotation driving means so as to be able to suppress eye-opening due to rotation vibration of said rotation driving section. 3. The method according to claim 1, wherein the rotation position of the rotation drive unit is controlled using a dual control system in which an output position control by a stepping motor and a check and correction by an encoder and other rotation angle detection units are performed. Item 2. A laser welding apparatus for piping according to Item 1.