JPH0550294A - Method for joining metal pipe - Google Patents

Abstract

PURPOSE:To provide a metal pipe joining method capable of simply and satisfactorily joining metal pipes having long lengths and narrow diameters into sleeve coupling with a simple structured device. CONSTITUTION:The tip end part of a pipe 1 inserted into a sleeve 2, a sleeve 1 is calked, and the pipe 1 is preliminarily fixed to the sleeve 2. Then, the sleeve 2 is clamped by a split chuck 21 that is separable to the direction of the diameter, the split chuck 21 is rotated while the pipe axis is a rotary center axis, the end part of the sleeve is heated and fused along the circumference while turning the pipe 1, and the pipe 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 for joining metal pipes, and particularly to 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 by a sleeve joint or a butt joint. Regarding the method of joining. 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.

Further, in the case of joining the pipes by the sleeve joint, if there is a gap between the sleeve and the pipe, the molten metal flows into the gap when the joint is heated and melted, and the sleeve and the pipe are sufficiently joined. There are times when you don't. Therefore, it is necessary to prevent a gap from being formed between the sleeve and the tube. However, for example, when joining a tube through an optical fiber with a sleeve joint, it is necessary to move the sleeve and cover the tube after fusing the optical fiber. In such a case, it is necessary to provide a gap between the sleeve and the tube so that the sleeve and the tube can play with each other, resulting in a defective joint as described above.

The present invention provides a method for joining metal pipes which enables easy and good sleeve jointing of long and thin metal pipes with a device having a simple structure.

[0006]

In the method for joining metal pipes according to the present invention, the tip of the pipe is inserted into the sleeve, the sleeve is caulked, and the pipe is fixed to the sleeve in advance. Then,
The sleeve is gripped by a split chuck that is separable in the radial direction, the split chuck is rotated around the tube axis as the rotation center axis, and the ends of the sleeve are heated and melted along the circumference while twisting the tube to join the tubes.

A laser as a heating source, a plasma welding heat source,
TIG welding heat source, electron beam, etc. are used. Also,
An inert gas such as argon or helium is used as the shield gas.

In order to grip the tube or the 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. 36 tubes
0 degree twisted and welded, or at least 180
Weld while twisting, then at least 18 in the opposite direction
You may make it weld, twisting 0 degree | times.

Further, a metal foil, a plastic foil, or a plate may be wound several times around the outer peripheral surface of the sleeve tip portion and caulked. As the metal foil, stainless steel, aluminum or other non-corrosive metal is suitable. Also,
Teflon resin, epoxy resin, or the like is used as the plastic foil or plate. The width of the metal foil is about 5 mm.

[0010]

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.

Further, since the tip of the pipe is inserted into the sleeve, the sleeve is caulked, and the pipe is fixed to the sleeve in advance and then joined, the molten metal does not flow into the void when the joint is heated and melted. ..

When a metal foil or the like is wound a plurality of times around the outer peripheral surface of the sleeve tip portion and caulked, the metal foil layer or the plastic foil layer is deformed and the conformability with the caulking tool is improved. As a result, the tip of the sleeve can be uniformly crimped.

[0013]

1 shows an example of a metal pipe joining apparatus for carrying out the method of the present invention. As shown in the drawing, upper and lower split bearings 15 are attached to the pedestal 11.
The bearing 15 is composed of a semi-annular lower metal 16 fixed to the pedestal 11 and an upper metal 17 fixed to a cover 18 that is removable from the pedestal 11. Lower metal 1
6 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 sleeve 2 is attached to the split chuck 21.
A grip groove 29 for gripping is penetrated along the axis.

An electric motor 35 with a speed reducer is mounted on the mount 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 metal fitting 41 is supported on the pedestal 11 via a stand 13. As shown in FIG. 3, the pipe holding metal fitting 41 is composed of a cylindrical main body 42 which is divided into upper and lower parts. The lower member 43 of the cylindrical main body 42 is fixed to the stand 13. The cylindrical main body 42 is provided with a grip flange 46 for gripping the metal tube 1 to be joined near the rear end. When the metal pipe 1 is held by the lower member 42 and the upper member 44, an annular gas flow passage 48 is formed between the metal pipe 1 and the cylindrical main body 42, and a portion of the gas flow passage 48 near the tip end is formed. Is narrowed to become a shield gas ejection port 49. A gas inlet 51 is provided at the center of the upper member 44, and a shield gas supply pipe 53 is connected to the gas inlet 51. The pressure control valve 5 is installed in the shield gas supply pipe 53.
A gas cylinder 57 is connected via 5. The gas cylinder 57 is filled with pressurized argon gas.
As shown in the figure, the split chuck 11 joins the sleeve 2
And the pipe holder 41 holds the pipe 1.

Further, the welding head 6 is provided adjacent to the gantry 11.
1 is arranged. YAG laser light is guided to the welding head 61 from a YAG laser oscillator through an optical fiber (neither is shown).

The pipes are connected by the above-mentioned joining device as follows. 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 connecting pipe is a stainless steel pipe (SUS304 outer diameter 1.2 mm, inner diameter 0.8
mm).

Before the pipes 1 are joined together, one of the pipes 1 is covered with the sleeve 2, and the ends of the optical fibers 9 exposed from both pipes 1 are fused. Then, the tubes 1 are set on both ends of the sleeve 2 so that the overlap margin is about 20 mm. The sleeve 2 is fixed to the tube 1 by caulking the tip of the sleeve 2. To caulk the front end of the sleeve 2, as shown in FIG. 4, the stainless steel foil 7 is wound around the sleeve tip about 5 times, and then the caulking tool 65 strongly presses the sleeve tip. The caulking tool 65 has a trapezoidal opening 66 that is open to the outside. The number of times the stainless steel foil 7 is wound is appropriately adjusted depending on the outer diameter of the sleeve 2 and the size of the opening 66 of the caulking tool 65.
When the caulking is finished, the stainless steel foil 7 is removed. The sleeve 2 is gripped by the split chuck 21 so that the caulking portion 3 of the sleeve 2 projects from the split chuck 21. Further, the pipe 1 is held by the pipe holding metal fitting 41. 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 makes one rotation, and when the joining is completed, makes one rotation in the opposite direction to remove the twist of the tube 1. During joining, the shield gas is ejected from the shield gas ejection port 49 of the pipe holding metal fitting 41 toward the joint portion 5. The flow rate of the shield gas is 25 l / min.

[0020]

According to the method for joining 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.

The tip of the tube is inserted into the sleeve, the sleeve is caulked, and the tube is fixed to the sleeve in advance and then joined. Therefore, no gap is generated between the sleeve and the pipe, and good joining can be obtained.

When a metal foil or the like is wound a plurality of times around the outer peripheral surface of the sleeve tip portion and caulked, the metal foil layer and the plastic foil layer are deformed, and the compatibility with the caulking tool is improved. As a result, the leading end of the sleeve can be uniformly and firmly caulked. Further, by adjusting the number of windings of the metal foil or the like, it is possible to crimp various types of sleeves having different outer diameters by using one type of crimping tool.

[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 cross-sectional view of a pipe holding metal object.

FIG. 4 is a diagram illustrating a method of crimping a sleeve.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Metal tube 29 Gripping groove 2 Sleeve 35 Motor 3 Caulking part 38 Driving gear 5 Joining part 41 Pipe holding metal fitting 7 Metal foil 49 Shield gas ejection port 9 Optical fiber 53 Shield gas supply pipe 11 Frame 57 Gas cylinder 15 Bearing 61 Welding head 21 Split Chuck 65 Caulking tool 22 Driven gear

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location F16L 13/02 7123-3J

Claims (2)

[Claims] 1. A method of joining two metal pipes with sleeve end joints with the pipe end faces facing each other, wherein the tip of the pipe is inserted into the sleeve, the sleeve is caulked, and the pipe is fixed to the sleeve in advance. It is characterized in that the sleeve is gripped by a split chuck that can be separated in any direction, the split chuck is rotated around the tube axis as the rotation center axis, and the end of the sleeve is heated and melted along the circumference while twisting the tube to join the tubes. Method of joining metal pipes. 2. The method for joining metal pipes according to claim 1, wherein a metal foil, a plastic foil, or a plate is wound around the outer peripheral surface of the sleeve tip portion a plurality of times and caulking is performed.