JPH0239605Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to the improvement of a so-called floating type plug used for manufacturing metal tubes containing relatively small-diameter wire rods.

[Conventional technology]

With the recent development of optical fiber cables, as an application technology, it has been considered, for example, to incorporate optical fibers into the structure of an overhead ground wire, and technology for inserting optical fibers into metal tubes such as aluminum is being considered. .

However, even if you try to insert an ultra-thin electric wire or optical fiber directly into a long and thin metal tube, you can only insert it for about 10 to 20 meters. Even if you try to connect wires such as fiber or optical fiber and pull it in,
The piano wire can only fit about 50m, so from 100m
It is virtually impossible to draw wire into a 1000m long metal pipe.

The inventors succeeded in manufacturing the desired metal tube with a built-in wire by attaching aluminum tape vertically to the wire, welding the seams, and reducing the diameter of the metal tube in multiple stages. As a result of pursuing
When reducing the diameter of metal tubes that are welded together in stages, that is, axial joints, it is extremely effective to use a plug inside the metal tube and a diameter reduction die outside the metal tube to reduce the diameter by working together. It was found that improvements should be made.

The conventional plug used here has a hollow hole 2' in the shaft center through which the wire is inserted, as shown in Figure 1 (immediately after the plug is inserted into the pipe), and works together with the die to reduce the diameter of the metal pipe. a head 1' that can perform
It consists of a metal pipe 3' such as SUS, and a packing 4' having an outer diameter equal to the outer diameter of the head 1' at the end of the metal pipe 3' such as SUS. While injecting lubricant 5' into the cavity with a syringe 9 or the like as shown in Fig. 5A, rotate the plug and push it into the opening of the metal pipe 6'.
It was as shown in Figure B.

[The problem that the idea aims to solve]

However, in such a plug structure, as a result of the lubricant flowing uniformly over the entire surface of the exposed metal pipe 3', more lubricant than is necessary for drawing or reducing the diameter of the metal pipe is constantly supplied to the head of the plug. Especially when restarting diameter reduction (the first stage of forming a new metal pipe and reducing its diameter), lubricant tends to leak from the unwelded parts of the metal tape that forms the metal pipe, and the 50m
However, when the pipe was expanded, the lubricant ran out and the pipe broke.

This phenomenon of lubricant leakage can be seen in the schematic diagram shown in Figure 3 when performing the first stage of pipe expansion using the plug shown in Figure 1.
As shown in the figure, when the expanded metal tube is reduced in diameter, the lubricant 5' moves toward the plug 1', resulting in the state shown in the figure. In this case, the pressure of the lubricant immediately in front of the plug is high, and it is thought that the amount of lubricant leaking out during pipe expansion increases. However, 7' is a wire rod,
8' indicates a die. The present invention was developed based on the recognition that solving the problems of the prior art is an important issue for advantageous production.

[Means for solving the problem] [Operation] The present invention was made in view of this situation, and as shown in Figure 2 (immediately after inserting the plug into the pipe), it is possible to insert a wire into the shaft center. It has a hollow hole 2 that
Head 1 capable of reducing the diameter of a metal tube in cooperation with a die
and a metal pipe 3 made of SUS or the like extending to the rear side and having an inner diameter equal to the diameter of the hollow hole 2, and an outer diameter equal to the outer diameter of the plug head 1 provided at the end and in the middle of this metal pipe. This plug is made up of a plurality of gaskets 4 having a plurality of diameters, and has a plurality of cavities in the exposed portion of the outer periphery of the metal pipe 3.
Note that 6 is a metal pipe (formed metal pipe before diameter reduction)
shows. FIG. 4 shows a schematic diagram of the case where the first stage of pipe expansion is performed using the plug shown in FIG. move toward the front of the plug 1 and each gasket 4, respectively, resulting in the state shown in the figure.
In this case, the amount of lubricant 5 in each cavity is much smaller than in FIG. 3, so the pressure it exhibits is also small;
It is thought that the amount of leakage during pipe expansion will also be reduced. However, 7 indicates a wire rod and 8 indicates a die.

〔Example〕

Aluminum tape with a thickness of 0.6 mm and a width of 47.1 mm is continuously formed into a circular tube shape and welded to form an outer diameter of 15.0 mm.
Insert piano wire inside while forming a circular tube,
When reducing the diameter of a circular pipe and taking it out, the pipe plug of the present invention was used to reduce the diameter. In Fig. 2, the plug head 1 made of die steel and the metal pipe 3 made of SUS metal are integrally formed, and the outer diameter of the large diameter part of the plug head 1 is 13.0 mm, and the outer diameter of the metal pipe 3 is 13.0 mm. The length of 6.4mm was 1m. As the packing 4, a disk made of lubricant-insoluble rubber or plastic may be used, but since the outer diameter is small, wrap a layer of vinyl tape and form it into a disk shape with an outer diameter of 12.5 mm. They were installed at three locations as shown in the figure.

To start pipe expansion, insert the above-mentioned pipe expansion plug into the hole farthest from the plug head while using a plug push rod from the starting end of the formed outlet of the metal tube 6 made of aluminum tape. By successively injecting lubricant with a syringe, a plug for expanding the tube is inserted into the metal tube 6 and the entire cavity is filled with the lubricant. As a lubricant, the viscosity is 500Cst (38℃)
Waimatsuku H-2 (Japan Grease Co., Ltd. product name)
was used.

As shown in FIG. 4, a piano wire is used as the wire 7, and is inserted into the center hole of the plug.
While pulling the tube, the diameter was reduced using a die 8 placed on the head of the tube elongation plug. The tensile speed was 5 m/min. At this time, as the metal tube 6 moves forward, the lubricant 5 adheres to the inner surface of the metal tube 6 and comes out, but as the amount of lubricant 5 in the space closest to the plug head 1 decreases, The lubricant is sent from a space farther from the plug head to a space adjacent to the plug head, adheres to the metal tube 6, and exits. When the length of the metal tube 6 was reduced to 500 m, the metal tube 6 was opened at the plug for expansion and observed. As the metal tube 6 moves forward, the lubricant 5 spreads to the area adjacent to the plug head. The lubricant at any time during diameter reduction is allowed to be transferred from the cavity and refilled.
It is estimated that the state is as shown in FIG. 4 due to the influence of gravity on the lubricant 5 and the tension caused by the metal tube 6.

When we formed and expanded a metal pipe while inserting piano wire using the above-mentioned pipe-stretching plug, we could only manufacture about 50 m using conventional technology.
By using the plug for pipe expansion of the present invention, wasteful escape of lubricant is reduced, and pipe lengths up to 2000 m can be manufactured.

[Effect of idea]

Therefore, in the plug of the present invention, lubricant is first injected from the space farthest from the plug head to the spaces closest to it, and while filling all the spaces with the lubricant, the plug is pushed into the main metal pipe whose diameter is to be reduced. When the diameter of the metal tube is reduced while moving the metal tube forward in response to continuous welding of the metal tape in cooperation with the die, the minimum necessary amount of lubricant adheres to the metal tape and fills the empty space on the plug head side. When the lubricant becomes low, it leaks and moves from the space farther from the plug head to the space closer to the plug head, causing unwelded parts of the metal pipe that tend to occur when using the plug shown in Figure 3. There is no fear that the metal pipe will escape from the pipe, and the diameter reduction work of a long metal pipe can be carried out for a long time.

The packing is preferably one that has appropriate slipperiness and is insoluble in lubricants, such as a disc-shaped one made of rubber, plastic, etc., or a disc-shaped one wrapped in layers of vinyl tape.

[Brief explanation of the drawing]

FIG. 1 is a partially longitudinal side view showing the structure of a conventional plug in a state where a metal tube is brought out, and FIG. 2 is a partially longitudinal side view showing the structure of a metal pipe in a state of being led out by a plug of the present invention. FIG. 3 is a cross-sectional view showing the state of pipe expansion using a conventional plug. FIG. 4 is a sectional view showing the state of pipe expansion using the plug of the present invention, and FIG. 5 is a sectional view showing the state of lubricant injection when using a conventional plug. 1, 1'... Head, 2, 2'... Hollow hole, 3,
3'...Metal pipe, 4, 4'...Putskin, 5,
5'...Lubricant, 6,6'...Metal tube, 7,7'
...Wire, 8, 8'...Die, 9...Syringe, etc.

Claims (1)

[Scope of utility model registration request] A head 1 which has a hollow hole 2 through which a wire 7 is inserted and which can reduce the diameter of the metal pipe 6 in cooperation with a die 8, and a metal pipe with an inner diameter equal to the hollow hole 2 on the back side of the head 1. 3, and a plurality of packings 4 having an outer diameter equal to the outer diameter of the plug head 1 provided at the end and in the middle thereof, and holding lubricant 5 in a plurality of tubular cavities on the outer periphery of the metal pipe 3. A plug for metal pipe expansion with a built-in wire rod.