JPH0632248B2 - How to connect conductors - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a conductor connecting method, and more particularly to a conductor connecting method suitable for connecting a large-sized cable conductor.

[Technical background of the invention] Conventionally, as a method for connecting cable conductors, a method using a compression sleeve or a method by welding is known.

The method using the compression sleeve does not require heating at the time of connection and does not deteriorate the insulator, but on the other hand, the outer diameter of the connection part is larger than the outer diameter of the conductor, so that the finished outer diameter is large and the mechanical part of the connection part However, it has a drawback that the electrical properties are easily deteriorated.

On the other hand, the welding method can obtain a relatively good connection portion, but there is a risk that the insulator near the connection portion will be deteriorated by the heat during welding. A method of forcibly cooling the outer circumference of the conductor is known.

As shown in FIG. 4, the method of forced cooling is such that the end portions of the conductors 1 and 1'to be connected are butted, the butted portion is cut out in an X shape, and the conductor is surrounded in the vicinity of the end portion. The cooling boxes 2 and 2 are attached, and the cut portion is TIG-welded to form the build-up portion 3 while passing water in the box in the arrow direction. The cooling box 2 has a split structure as shown in FIG. 5, which facilitates attachment / detachment to / from the conductor.

[Problems of the Background Art] However, in the above connection method, in the case of a large-sized conductor, even if the amount of water is increased, the temperature of the conductor reaches 150 to 180 ° C at a position 200 mm from the welded portion, and heat to the insulator is generated. It was difficult to reduce the impact.

Further, in the case of TIG welding, an arc is not generated unless the welding torch is brought close to the member to be welded. Therefore, the cutting angle of the cut portion (cut portion) must be set large, which inevitably lengthens the welding time and reduces the Easily deteriorated by heat,
Particularly, in the case of a large-sized conductor, there is a drawback in that a considerable skill is required for the welding connection because the heat diffusion rate becomes large.

Further, since the welded area becomes large, oxides and slag are easily entrained, and the properties of the connection portion are not sufficiently satisfactory.

[Object of the Invention] The present invention has been made in order to solve the above problems.
An object of the present invention is to provide a conductor connecting method that shortens the welding time, eliminates the thermal effect on the insulator by efficiently cooling the conductor near the welded portion, and can easily obtain a good connecting portion. And

[Summary of the Invention] That is, in the conductor connecting method of the present invention, a pair of conductors having end faces that are substantially orthogonal to the central axis are made to face each other at a predetermined interval on the central axis, and the outer circumferences of the facing portions of the both conductors are made. , Surrounded by a separable cylinder having an opening on one side,
Attach a cooling box that surrounds both conductor end portions,
After jetting carbon dioxide into the cooling box to cool the conductor, a welding rod is inserted into the gap through the opening of the cylinder to MIG-weld both conductor ends, and then the cylinder and the cooling box are separated. It is characterized by removing.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view of a welded portion showing a method for connecting conductors according to the present invention, in which the end faces of a pair of copper stranded conductors 1 and 1'to be connected are substantially perpendicular to the axis of the conductor. Disconnect with
The end faces are arranged apart from each other, and are supported by a tubular body 3 made of a refractory material having no wettability with a molten metal such as a carbon material or a ceramic.

The cylindrical body 3 has a split structure for facilitating attachment / detachment to / from the outer periphery of the conductor, and the space 3 surrounding the conductor end of the welded portion.
It holds the molten metal in a and serves as a gas seal.

The upper portion of the space 3a is opened, and the welding rod 4 is inserted from the opened portion 3b to perform MIG welding. Space 3 at this time
Since a has an inner diameter slightly larger than the outer diameter of the conductor, the slag is extruded outward, and since the area of the open portion 3b is small, it is possible to prevent the inclusion of oxide or sludge in the welded portion.

The MIG welding is a well-known welding method in which an arc is generated between a metal electrode wire and a base material in an inert gas atmosphere, and the base material and the electrode wire are melted by arc heat to form a weld. Since the arc heat is concentrated and strong, the penetration is deep, and since copper has a good heat conduction, it is particularly effective for welding copper, aluminum and their alloys. Therefore, by arranging a copper short wire in the space 3a of both copper stranded wire conductors supported by the tubular body 3 and bringing the welding rod into contact with the copper short wire, it is easy to generate an arc at the start of welding. can do.

In addition, since MIG welding has an extremely high welding speed and is more efficient than TIG welding, it is suitable for welding large-sized conductors, and the welding time can be greatly shortened.

Furthermore, since the current density is remarkably high, fine droplets are projected from the electrode at high speed, so the ripples on the bead surface are extremely small and not only a smooth and beautiful bead is formed, but also the arc has a strong directivity. Since it is held, there is an advantage that it can be easily welded in any of the downward, vertical, and upward postures.

In order to reduce the effect of heat during welding, in the vicinity of the welded portions of the conductors 1 and 1 ', separable cooling boxes 5 and 5', each of which is surrounded by the outer circumference of the conductor and whose one end side is open, are attached. CO ₂ gas is ejected from the cylinder 7 through the nozzles 6 and 6 ′ provided on the cylindrical outer wall of the cooling box.

In addition, 8 and 8 ′ are sealing agents made of heat resistant material,
A heat removing agent (for example, cool heat) can also be used for this.

CO ejected from the nozzles 6 and 6'into the cooling boxes 5 and 5 '
_{The 2} gas is cooled by the rapid expansion, becomes dry ice particles and adheres to the conductor, and is rapidly vaporized by the heat from the welded portion to cool the conductor.

FIG. 2 shows another structure of the cooling box 9, which is composed of an outer circumference 10 of a split structure and both side walls that close the space between the conductor and the outer cylinder, and the outer cylinder has CO ₂ gas. A nozzle 11 and a gas discharge hole 12 for ejecting the gas are provided. At this time, it is effective to wind a heat-resistant tape 13 such as silicone rubber around the conductor to prevent gas leakage and promote generation of dry ice particles due to a weak heat insulating effect.

FIG. 3 shows still another embodiment of the present invention, in which parts common to those in FIG. 1 are designated by the same reference numerals.

In this embodiment, the cooling boxes 12, 12 'corresponding to the cooling boxes 5, 5'shown in FIG.
A space 12b, 12b 'is formed between the conductors 1, 1'and covered with a, 12a'.

In this embodiment, the release portion is smaller than that of the first embodiment, so the cooling efficiency is improved.

In the above embodiment, when the welding, the ends of the conductors 1, 1 'is supported by a cylindrical body 3 with 5~10mm apart, attached to the cooling box to the conductor near, CO ₂ gas into the cooling box MIG welding is performed while ejecting.

The molten metal is held in the cylinder between the conductor end portions, and solidification proceeds from the lower portion thereof as welding progresses.

After welding, the cylindrical body 3 and the cooling box 5 are removed, and burrs on the welded portion are ground to complete the connection.

[Effects of the Invention] As described above, according to the conductor connecting method by MIG welding of the present invention, it is not necessary to cut the conductor butt portion to be connected by V or X, and the welding time can be shortened. Since it is sufficiently cooled, it is possible to prevent the thermal effect on the insulator, and thus it is possible to obtain a connection part having good electrical and mechanical properties.

[Brief description of drawings]

FIG. 1 is a side view of a welded portion showing an embodiment of the connection method of the present invention, FIG. 2 is a cross sectional view of a cooling box used in the present invention, and FIG. 3 shows another embodiment of the present invention. FIG. 4 is a side view of the welded portion, FIG. 4 is a side view showing a conventional welding method, and FIG. 5 is a sectional view taken along the line AA ′. 1, 1 '... conductor 3 ... cylinder 5, 5', 9, 12, 12 '... cooling box 6, 6' ... nozzle 7 ... cylinder

Claims (1)

[Claims] 1. A pair of conductors having end faces that are substantially orthogonal to a central axis are opposed to each other with a predetermined gap on the central axis, and outer peripheries of opposed portions of the two conductors can be divided with an opening on one side. And a cooling box that surrounds the conductors in the vicinity of the end portions of the conductors, and while cooling the conductor by jetting carbon dioxide gas into the cooling box, the cooling box is inserted into the gap portion from the opening portion of the cylinder body. Insert a welding rod and connect both ends of the conductor with M
A method for connecting conductors, characterized in that the cylinder and the cooling box are removed after IG welding.