JPH0577088A - Method and device for joining metallic tube - Google Patents

Abstract

PURPOSE:To provide the method and the device so that a metallic tube of long size and fine diameter can be simply joined with a device of simple structure. CONSTITUTION:The neighborhood of a tube end or a sleeve 7 is clamped with a divided chuck 21 which can be divided in the diametral direction. And the divided chuck is rotated in making the tube axis as the rotation central axis, the tube end part or the sleeve end part is heated and melted along the circumference while twisting the tube 1, and the tube 1 is joined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for joining metal pipes, and more particularly to a sleeve joint for a long and thin metal pipe having a length of several tens of meters or more and an outer diameter of about 1 to several mm. TECHNICAL FIELD The present invention relates to a method for joining by a butt joint and an apparatus for the method. INDUSTRIAL APPLICABILITY The present invention is used for manufacturing a long and thin metal tube such as an optical fiber coating tube and for connecting a long and thin metal tube through which an optical fiber is passed.

[0002]

2. Description of the Related Art An optical fiber coated tube is an example of a long and thin metal tube. This optical fiber cladding has an outer diameter of 1.2 mm and an inner diameter of 0.9 mm,
The length is several tens of kilometers. Such a metal tube has an outer diameter of 2 to
A metal tube of about 25 mm is stretched and reduced in diameter to produce one continuous tube. However, because of the small diameter, it is easy to break during the drawing process. Therefore, the length is several tens of meters to several kilometers.
A number of pipes are joined together. There should be no swelling or protrusion of the molten metal on the inner surface side of the joint, as well as a slight bulge. This is because it becomes an obstacle when passing the optical fiber through the tube. For this reason, highly accurate welding is required, laser energy is widely used because heat energy can be concentrated on the joint, and output adjustment is easy.
Further, a long and thin metal tube is usually wound around a spool. To connect the metal pipes, two spools are unwound, the metal pipes are paid out from the respective spools, the pipe end faces are opposed to each other, and the two pipes are joined by a sleeve joint or a butt joint.

[0003]

When welding along the circumferential direction of the pipe joint, if the metal pipe is long or wound on a spool, the pipe cannot be rotated. Therefore, conventionally, welding was performed while rotating the welding head along the circumference of the pipe. For this reason, the welding apparatus is complicated and the work is complicated.

The present invention provides a method of joining metal pipes and a device for joining metal pipes having a long structure and a small diameter, which can be easily joined by a device having a simple structure.

[0005]

In the method for joining metal pipes according to the present invention, the vicinity of the pipe end or the sleeve is gripped by a radially separable split chuck. Then, the split chuck is rotated with the tube axis as the rotation center axis, and while twisting the tube, the tube end or the sleeve end is heated and melted along the circumference to join the tubes. A laser, a plasma welding heat source, a TIG welding heat source, an electron beam or the like is used as a heating source.

The metal pipe joining apparatus of the present invention is separable in the radial direction, and a split chuck for holding the pipe or sleeve to be joined, a bearing rotatably supporting the split chuck and separable in the radial direction. , And a device for rotationally driving the split chuck. In order to grip the tube or sleeve with the split chuck, the split chuck is tightened with a screw, or a radial load is applied to the split chuck.
A laser is used for heating and melting. To rotate the split chuck, a gear transmission mechanism, a belt transmission mechanism or a chain transmission mechanism is used. An electric motor, a hydraulic motor, or the like is used as the power source of these, or may be manual. The tubing may be twist welded 360 degrees or may be welded twisting at least 180 degrees and then twisting at least 180 degrees in the opposite direction.

[0007]

Since the metal tube has a small diameter, the tube can be twisted with the tube axis as the rotation center axis. Therefore, the joint can be welded over the entire circumference with the welding head fixed. The gripping members constituting the split chuck are pressed against each other in the radial direction to grip the pipe, and are separated in the radial direction to be removed from the pipe. Therefore, it is easy to attach / detach even a long tube or a tube wound on a spool.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the metal pipe joining apparatus of the present invention. As shown in the drawing, upper and lower split bearings 15 are attached to the pedestal 11. The bearing 15 includes a semi-annular lower metal 16 fixed to the pedestal 11 and the pedestal 1
It is composed of an upper metal 17 fixed to a cover 18 which is detachable with respect to 1. The lower metal 16 and the upper metal 18 are arranged at intervals in the axial direction. The bearing 15 rotatably supports the split chuck 21.

As shown in FIG. 2, the split chuck 21 has two gripping members 21a and 21 which are split into upper and lower parts.
b. The central part of the split chuck 21 is
It is a driven gear 22 and a step portion 23. Driven gear 2
2 and the step portion 23 are respectively connected to the bearing 15
It is a sliding portion 25 that fits into the sliding portion 25. The driven gear 22 and the step portion 23 are in contact with the end surfaces of the lower metal 16 and the upper metal 17, so that the split chuck 21 does not shift in the axial direction. The two gripping members 21a and 21b are
Connected by screws 26. A shaft portion 27 extends from the sliding portion 25. The split chuck 21 has a grip groove 29 for gripping the metal pipe 1 to be joined, which penetrates along the axial center. As shown in FIG. 3, the split chuck 21 is provided with a laser beam introducing hole 31 penetrating in the radial direction near the tip thereof, and a slit 32 extending from the laser beam introducing hole 31 toward the tip is cut. Further, at the position of the laser beam introduction hole 31, a relief groove 33 is cut along the circumference on the surface of the grip groove 29.

An electric motor 35 with a reducer is installed on the pedestal 11
The drive gear 38 is fixed to the output shaft 36 of the motor 35. The drive gear 38 meshes with the driven gear 22.

A tube holding fitting 43 is supported on the frame 11 via a stand 13. The tube holding metal fitting 43 is also divided into two parts, the lower member 44 is the stand 13
Is stuck to. Further, as shown in FIG. 4, a grip flange 4 for gripping the metal pipe 1 to be joined to the pipe holding metal fitting 43.
5 is provided near the rear end. Furthermore, the pipe holding metal fitting 4
An assist gas supply pipe 47 is connected to the central portion of 3. A pressurized argon gas cylinder (not shown) is connected to the assist gas supply pipe 47. As shown in FIG. 1, the split chuck 11 holds one pipe 1 to be joined, and the pipe holding metal fitting 43 holds the other pipe 1.

Further, the welding head 5 is provided adjacent to the gantry 11.
1 is arranged. YAG laser light is guided to the welding head 51 from a YAG laser oscillator through an optical fiber (neither is shown).

The above-mentioned joining device connects the pipes as follows. The connecting pipe is a stainless steel pipe (SUS30
4 outer diameter 1.2 mm, inner diameter 0.8 mm). A conical cone with an apex angle of 120 ° is pressed against the end face of the pipe 1 to be connected and rotated, the pipe end portion 2 is flared in advance as shown in FIG. 5, and the end face 3 is cut with a surface perpendicular to the pipe axis. And polish it.

The two pipes 1 to be connected are butted against each other, and the two pipes 1 are sandwiched by the split chuck 21 so that the flare-like expanded pipe end portion 2 is located in the relief groove 33.
Then, the screw 26 is tightened to firmly grip the tube 1. Then, YAG laser light is irradiated through the laser light introducing hole 31 to temporarily attach the joint portion 5. At this time, the split chuck 2
1 is rotated and the tube 1 is twisted, and YAG laser light is irradiated to the joint 5 at 90 ° intervals one pulse at a time to perform spot welding. Further, one of the tubes 1 is held by the tube holding metal piece 43, and the assist gas is ejected from the tip of the tube holding metal piece 43. The flow rate of the assist gas is 25 l / min. The assist gas flows from the slit 32 at the tip of the split chuck 21 to the joining portion 5
And seal the weld. When the temporary attachment of the two pipes 1 is completed in this way, the split chuck 21 is loosened, and the temporary attachment portion is pulled out to the outside of the split chuck 21.
Is held by the split chuck 21, and the other pipe 1 is held by the pipe holding fitting 43. Then, the motor 35 is driven to rotate the split chuck 21, and the pipe joining portion 5 is laser-welded while twisting the pipe 1. The split chuck 21 rotates once,
When the joining is completed, the pipe 1 is twisted once in the opposite direction to remove the twist. At this time as well, as in the case of tack welding, the pipe holding hardware 4
Assist gas is ejected from 3 toward the joint 5.

Next, joining of pipes by a sleeve joint will be described. In this embodiment, a stainless steel pipe (SUS304) having an optical fiber (outer diameter of 0.25 mm) passed through the pipe.
External diameter 1.2 mm, internal diameter 0.8 mm) is connected. The sleeve is a 640 mm long stainless steel tube (SUS304 outer diameter 1.7 mm, inner diameter 1.3 mm).

The split chuck is different in the pipe joining device using the sleeve joint. As shown in FIG. 6, the split chuck 55 is not provided with a laser beam introduction hole, a slit and a clearance groove at its tip. It should be noted that FIG. 6 shows a pipe holding metal piece 57 that is not provided with an assist gas supply pipe.

Before the pipes 1 are joined together, one of the pipes 1 is covered with the sleeve 7, and the ends of the optical fibers 9 exposed from both pipes 1 are fused. Next, the tubes 1 are set on both ends of the sleeve 7 so that the overlap margin is about 20 mm. The distal end of the sleeve 7 is caulked to fix the sleeve 7 to the tube 1. The sleeve 7 is gripped by the split chuck 55 such that the tip of the sleeve 7 projects from the split chuck 55 by several mm. Further, the tube 1 is held by the tube holding metal piece 57. Then, the tip portion of the sleeve 7 is laser-welded in the same manner as the butt welding.

FIG. 7 shows another example of the pipe holding metal piece 59. Since the tube holding metal piece 59 has a spiral shape, the tube can be removed from the tube holding metal piece 59 without splitting it in half. Therefore, the tube can be held with a simple structure.

FIG. 8 shows another example of the split chuck. An adapter 61, which is divided into upper and lower parts, is attached to the tip ends of the gripping members 21a and 21b by screws 63. The adapter 61 includes a shaft portion 27 similar to that shown in FIG. A plurality of adapters 61 having different diameters of the grip grooves 29 are prepared, and the adapters 61 are replaced according to the diameter of the joining pipe. As a result, the main parts of the split chuck (the driven gear, the stepped part, the sliding part, etc.) can be used in common, so that the cost of the device is reduced.

[0020]

According to the method and apparatus for connecting metal pipes of the present invention, while the welding head is fixed, the split chuck holding the pipe is rotated and the pipe is twisted to weld the joint portion over the entire circumference. Therefore, a long and thin metal pipe can be easily joined with a device having a simple structure.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing an example of a metal pipe joining apparatus of the present invention.

FIG. 2 is a perspective view of a split chuck attached to the apparatus of FIG.

FIG. 3 is a detailed view of the tip of the split chuck.

FIG. 4 is a cross-sectional view of a pipe holding metal object.

FIG. 5 is a cross-sectional view of a tube tip portion processed into a flare shape.

FIG. 6 is a view explaining joining of pipes by a sleeve joint.

FIG. 7 is a perspective view showing another example of the pipe support metal member.

FIG. 8 is a perspective view showing another example of the split chuck.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Metal tube 32 Slit 5 Joint part 33 Relief groove 7 Sleeve 35 Motor 9 Optical fiber 38 Drive gear 11 Frame 43 Pipe holding metal fixture 15 Bearing 47 Assist gas supply pipe 21 Split chuck 55 Split chuck 22 Driven gear 57 Pipe holding metal fixture 29 Gripping groove 59 Tube holding hardware 31 Laser light introducing hole 61 Adapter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Hattori 3-5-4 Tsukiji, Chuo-ku, Tokyo Within Nippon Steel Welding Industry Co., Ltd. Inside Nippon Steel Welding Industry Co., Ltd.

Claims (7)

[Claims] 1. A method of joining two metal pipes with their end faces facing each other by a butt joint or a sleeve joint, wherein a pipe chuck near a pipe end or a sleeve is gripped by a radially separable split chuck, and a pipe shaft is rotated. A method for joining metal tubes, characterized in that the tube chuck is joined by rotating a split chuck as a central axis, heating and melting the tube end or the sleeve end along the circumference while twisting the tube. 2. The method for joining metal pipes according to claim 1, wherein when joining the pipes by a butt joint, the pipe ends are processed into flare shapes and the end faces are finished to be a face perpendicular to the pipe axis. 3. A split chuck which is separable in a radial direction and holds a pipe or a sleeve to be joined, a bearing which rotatably supports the split chuck and is separable in a radial direction, and a device which rotationally drives the split chuck. A metal pipe joining device, which is characterized by being provided. 4. The apparatus for joining metal pipes according to claim 3, wherein a pipe holding metal fitting which is separable in a radial direction is arranged near the pipe joining portion. 5. The metal pipe joining apparatus according to claim 3, wherein a spiral pipe holding metal fitting is arranged near the pipe joining portion. 6. The metal pipe joining apparatus according to claim 3, wherein a plurality of thermal energy input openings communicating with the pipe joining portion are provided along the circumferential direction at the tip of the split chuck. 7. The metal pipe according to claim 3, wherein an adapter is attached to a tip portion of the split chuck, and a plurality of thermal energy input openings communicating with a pipe joint portion are provided in the adapter along a circumferential direction. Joining equipment.