JP2839388B2 - Method and apparatus for joining metal tubes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for joining a metal pipe, and more particularly, to a method for joining a long and narrow 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 The present invention relates to a method and an apparatus for joining with a butt joint. INDUSTRIAL APPLICABILITY The present invention is used for manufacturing a long and small-diameter metal tube such as an optical fiber cladding tube and for connecting a long and small-diameter metal tube through which an optical fiber is passed.

[0002]

2. Description of the Related Art An optical fiber cladding tube is an example of a long and small diameter metal tube. This optical fiber cladding tube has, for example, an outer diameter of 1.2 mm and an inner diameter of 0.9 mm,
It is several tens of kilometers long. Such a metal tube has an outer diameter of 2
A metal tube of about 25 mm is stretched and reduced in diameter to produce one continuous tube. However, because of the small diameter, the wire is easily broken during the stretching process. Therefore, the length is several tens of meters to several kilometers.
About several tubes are joined. The inner surface of the joint should not have any slight bulge as well as dripping or protrusion of the molten metal. This is because it becomes an obstacle when passing the optical fiber through the tube. For this reason, high-precision welding is required, and laser welding, which can concentrate heat energy on a joint portion and easily adjust output, is widely used.
In addition, a long and thin metal tube is usually wound on a spool. To connect the metal tubes, the two spools are unwound, the metal tubes are unwound from each spool, and the two pipes are joined by a sleeve joint or a butt joint with the pipe end faces facing each other.

[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 device became complicated and the work was complicated.

SUMMARY OF THE INVENTION The present invention provides a method and an apparatus for joining metal tubes, which can easily join a long and small-diameter metal tube with a device having a simple structure.

[0005]

According to a method of joining metal tubes of the present invention, a plurality of thermal energy input openings are connected to a heat energy input opening by a radially separable split chuck provided along a circumferential direction. Aligning the joints, grasping the vicinity of the pipe end, rotating the split chuck with the pipe axis as the rotation center axis, inputting heat energy from the heat energy input opening while twisting the pipe, and performing multiple point tack welding carry out. Then, the pipe joint is shifted in the axial direction of the pipe so as to expose the welded pipe joint from the split chuck, and re-gripped with the split chuck.The pipe joint is heated and melted along the circumference while twisting the pipe, 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 a radial direction, a split chuck for gripping a pipe or sleeve to be joined, a rotatable support for the split chuck, and a radially separable bearing. , And a device that rotationally drives the split chuck. To grip the pipe or sleeve with the split chuck, the split chuck is screwed or a radial load is applied to the split chuck.
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 these power sources, and may be manual. The tube may be welded with a twist of 360 degrees or welded with a twist of at least 180 degrees and then with a twist of at least 180 degrees in the opposite direction.

[0007]

Since the metal pipe has a small diameter, the pipe can be twisted around the pipe axis as the rotation center axis. Therefore, the joint can be welded over the entire circumference with the welding head fixed. The holding members constituting the split chuck are pressed against each other in the radial direction to hold the tube, and are separated in the radial direction and removed from the tube. Therefore, it can be easily attached to and detached from a long tube or a tube wound on a spool.

[0008]

FIG. 1 shows an example of a metal pipe joining apparatus according to the present invention. As shown in the drawing, upper and lower split bearings 15 are attached to the gantry 11. The bearing 15 includes a semi-circular lower metal 16 fixed to the gantry 11 and the gantry 1
1 and an upper metal 17 fixed to a cover 18 that can be attached to and detached from the cover 1. The lower metal 16 and the upper metal 18 are arranged at intervals in the axial direction, respectively. The bearing 15 rotatably supports the split chuck 21.

As shown in FIG. 2, the split chuck 21 has two holding members 21a and 21
b. The central part of the split chuck 21
A driven gear 22 and a step 23 are provided. Driven gear 2
2 and the portion following the step portion 23 are the bearing 15
The sliding portion 25 fits into the sliding portion 25. The driven gear 22 and the stepped portion 23 come into 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
They are connected by screws 26. Further, a shaft portion 27 extends from the sliding portion 25. A gripping groove 29 for gripping the metal pipe 1 to be joined passes through the split chuck 21 along the axis. As shown in FIG. 3, a laser light introducing hole 31 penetrating in the radial direction is provided near the tip of the split chuck 21, and a slit 32 extending from the laser light introducing hole 31 toward the tip is cut. At the position of the laser beam introducing hole 31, a relief groove 33 along the circumference is cut on the surface of the holding groove 29.

The electric motor 35 with a speed reducer is
, And a drive gear 38 is fixed to an output shaft 36 of the motor 35. The drive gear 38 meshes with the driven gear 22.

A tube holder 43 is supported on the gantry 11 via a stand 13. The tube holding fitting 43 is also divided into upper and lower parts.
It is stuck to. As shown in FIG. 4, a holding flange 4 for holding the metal tube 1 to be joined is attached to the tube holding fitting 43.
5 is provided near the rear end. Further, the pipe holding fitting 4
An assist gas supply pipe 47 is connected to the center 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 21 holds one of the tubes 1 to be joined, and the tube holding bracket 43 holds the other tube 1.

Further, the welding head 5 is located adjacent to the gantry 11.
1 is arranged. YAG laser light is guided to the welding head 51 from a YAG laser oscillator via an optical fiber (both not shown).

[0013] The pipes are connected by the above-mentioned joining apparatus as follows. The connecting pipe is a stainless steel pipe (SUS30
4 The outer diameter is 1.2 mm and the inner diameter is 0.8 mm). A conical cone with a vertex angle of 120 ° is pressed against the end face of the pipe 1 to be connected and rotated, and as shown in FIG. 5, the pipe end 2 is flared in advance, and the end face 3 is cut in a plane perpendicular to the pipe axis. And polished.

The two pipes 1 to be connected are abutted with each other, and the two pipes 1 are sandwiched by the split chuck 21 such that the pipe ends 2 spread in a flared position are located in the relief grooves 33.
Then, the screw 26 is tightened to firmly grip the tube 1. Next, the bonding portion 5 is temporarily attached by irradiating a YAG laser beam through the laser beam introducing hole 31. At this time, split chuck 2
1 is rotated to twist the tube 1 and spot welding is performed by irradiating the joint 5 with one pulse of YAG laser light at 90 ° intervals. Moreover, retaining one of the tubes 1 in the tube holding bracket 43, Kang Ho
The assist gas is ejected from the tip of the metal fitting 43. The flow rate of the assist gas is 25 l / min. The assist gas is supplied from the slit 32 at the tip of the split chuck 21 to the joint 5.
To seal the weld. After the tack welding of the two pipes 1 is completed in this way, the pipes are integrated , the split chuck 21 is loosened, the tacked portion is pulled out of the split chuck 21, and one of the pipes 1 is gripped by the split chuck 21. ,
The other tube 1 is gripped by the tube holding fitting 43. Then, the motor 35 is driven to rotate the split chuck 21, and the pipe joint 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 reverse direction to remove the twist of the tube 1. At this time, as in the case of tack welding, the assist gas is ejected from the pipe holding fitting 43 toward the joint 5.

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

The pipe joining device using the sleeve joint has a different split chuck. As shown in FIG. 6, the split chuck 55 is not provided with a laser beam introduction hole, a slit, and a relief groove at its tip. FIG. 6 shows a pipe holding fitting 57 without an assist gas supply pipe.

Before joining the tubes 1, the ends of the optical fibers 9 exposed from the two tubes 1 are fused together with one sleeve 1 covered with a sleeve 7. Next, the tubes 1 are set at both ends of the sleeve 7 so that the overlap margin is about 20 mm. The tip of the sleeve 7 is swaged to fix the sleeve 7 to the tube 1. The sleeve 7 is gripped by the split chuck 55 such that the distal end of the sleeve 7 protrudes from the split chuck 55 by about several mm. Also tube holding
The tube 1 is held by the metal fitting 57. Then, the tip of the sleeve 7 is laser-welded in the same manner as in the butt welding.

FIG. 7 shows another example of the tube holding fitting 59. Since the tube holding fitting 59 has a spiral shape, the pipe can be removed from the tube holding fitting 59 without dividing the pipe into two pieces. Therefore, the tube can be held with a simple structure.

FIG. 8 shows another example of the split chuck. An upper and lower split adapter 61 is attached to the distal ends of the gripping members 21 a and 21 b with screws 63. The adapter 61 has the same shaft 27 as shown in FIG. A plurality of adapters 61 having different diameters of the holding grooves 29 are prepared, and the adapters 61 are replaced according to the diameter of the joining pipe. As a result, the main body portion (the driven gear, the step portion, the sliding portion, etc.) of the split chuck can be used in common, so that the apparatus cost is reduced.

[0020]

In the method and apparatus for connecting a metal pipe according to the present invention, the joint is welded over the entire circumference while rotating the split chuck holding the pipe and twisting the pipe while the welding head is fixed. Therefore, a long and small-diameter metal tube can be easily joined by a device having a simple structure.

[Brief description of the drawings]

FIG. 1 is a partially sectional side view showing an example of a metal pipe joining apparatus according to 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 a tip portion of the split chuck.

FIG. 4 is a sectional view of a tube holding fitting .

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

FIG. 6 is a diagram illustrating joining of tubes by a sleeve joint.

FIG. 7 is a perspective view showing another example of the tube support fitting.

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 Joining part 33 Escape groove 7 Sleeve 35 Motor 9 Optical fiber 38 Drive gear 11 Mount 43 Tube holding bracket 15 Bearing 47 Assist gas supply pipe 21 Split chuck 55 Split chuck 22 Driven gear 57 Tube holding bracket 29 Holding groove 59 Tube holding bracket 31 Laser beam introduction hole 61 Adapter

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI G02B 6/44 341 G02B 6/44 341 391 391 (72) Inventor Osamu Hattori 3-5-4 Tsukiji, Chuo-ku, Tokyo Nippon Steel Welding Industry Co., Ltd. In-company (72) Inventor Noriyasu Funayama 3-5-4 Tsukiji, Chuo-ku, Tokyo Nippon Steel Welding Industry Co., Ltd. (56) References JP-A-3-9307 (JP, A) (58) Fields investigated ( Int.Cl. ⁶ , DB name) B23K 37/053 B23K 9/028 B23K 10/02 B23K 15/00 B23K 26/00 G02B 6/00 Practical file (PATOLIS) Patent file (PATOLIS)

Claims (4)

(57) [Claims] 1. A method for joining two metal pipes by butt joints with the pipe end faces facing each other, wherein a plurality of heat
The lugi input opening is connected to the thermal energy input opening by a radially separable split chuck provided along the circumferential direction.
Align the joints , grip near the pipe end, rotate the split chuck with the pipe axis as the rotation axis, and twist the pipe while twisting the pipe.
Heat energy is input from the heat energy input opening and multiple points
Tack welding is carried out, and the welded pipe joint is
Shift the pipe in the pipe axis direction so that it is exposed from the split chuck.
Re gripped by the split chuck Te, the pipe joint <br/> heated and melted along the circumference while twisting the tube joining method of the metal tube, characterized by joining the pipe. 2. The metal pipe according to claim 1, wherein when the pipe is joined by a butt joint, the pipe end is worked into a flared shape, and the end face is finished to a plane perpendicular to the pipe axis by cutting and polishing. Joining method. 3. A split chuck which is separable in a radial direction and holds a pipe 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. Metal pipe joining equipment
A spiral pipe holding fitting is used for the split chuck at the pipe joint.
A joining device for metal pipes, wherein the joining device is arranged at a position opposite to the metal pipe. 4. A split chuck which is separable in a radial direction and holds a pipe to be joined, a bearing rotatably supporting the split chuck and separable in a radial direction, and a device for rotating and driving the split chuck. In the metal pipe joining apparatus provided , the tip of the split chuck or the tip of the split chuck is attached.
A metal pipe joining apparatus, wherein a plurality of thermal energy input openings communicating with the pipe joining portion are provided along the circumferential direction of the attached adapter .