JPS6161207B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of embedding a metal wire assembly in a metal gutter with solder, and particularly relates to a method of manufacturing a superconducting cable.

Conventionally, in order to manufacture a long copper trough like a superconducting cable in which a bundle of stranded wires is embedded with solder, the copper trough is placed at the bottom of a molten solder bath, and the bundle of stranded wires is continuously inserted into this. After sufficiently infiltrating the solder, the copper gutter was taken out from an outlet provided at one end of the molten solder bath, and manufacturing was continued while cooling. FIG. 1 is a cross-sectional view of a stranded wire, in which a plurality of tin-plated copper wires are twisted together to form a stranded wire 1, and the whole is formed into a rectangular shape. The dimensions of this rectangle are such that it can be accommodated in the groove of the gutter.

FIG. 2 is a sectional view showing the stranded wire of FIG. 1 embedded in a metal gutter with solder. Stranded wire 1 in Figure 1
is accommodated in the groove 3 and filled with solder 4. This shows an example of a superconducting cable 10, and the presence of voids between multiple metal wires or in the solder 4 is one of the causes of deteriorating the characteristics of the superconducting cable 10. It must be manufactured to avoid voids. In addition, in the case of the superconducting cable 10, the twisted wires 1 and the metal gutter 2 are made of copper.

The copper gutter 2 is pushed out from the outlet of a conventional molten solder bath in the state shown in Figure 2, but a holding plate is installed above the outlet to scrape off the molten solder that protrudes from the top surface of the copper gutter 2. At the same time, the stranded wire 1 is held down. Therefore, the molten solder is cooled and solidified from the top surface, and the air bubbles remaining between the twisted wires cannot escape, and voids are generated due to volume reduction during solder solidification. It had the disadvantage of being easy.

The object of the present invention is to provide a method for embedding a metal wire assembly into a metal gutter with solder without causing voids, and the feature is that a metal wire assembly can be embedded into a metal gutter by a holding plate installed on the top surface of the outlet. After flattening the top surface of the metal gutter, the metal gutter is cooled from the bottom to solidify the molten solder, thereby preventing voids from forming inside the metal gutter.

FIG. 3 is a perspective view showing a method for manufacturing a superconducting cable according to an embodiment of the present invention. A copper gutter 2 is installed in a molten solder tank 5 provided with an outlet 7 and covered with molten solder 4. A long twisted wire 1 is inserted obliquely into a groove 3 of a copper gutter 2. A diaphragm 6 of a vibrator comes into contact with this twisted wire 1 and vibrates the twisted wire 1 to expel air between the wires so that solder can penetrate sufficiently. While the stranded wire 1 is inserted into the groove 3 in this manner, the copper gutter 2 passes through the outlet 7, but at this time, the solder on the upper surface of the groove 3 is scraped off and the stranded wire 1 is taken out from the groove 3. It is held down with a holding plate 8 to prevent it from happening. Therefore, the copper gutter 2 exiting the outlet 7 has the cross-sectional shape shown in FIG.

Conventionally, since the solder was cooled in the above state, the solder 4 solidified from the top surface which was in direct contact with the air. However, in this embodiment, since the cooling device 9 is installed close to the bottom of the extruded copper gutter 2, the solder 4 in the copper gutter 2 solidifies from below. At this time, the air bubbles remaining in the solder 4 are expelled into the upper solder 4 which is still in a liquid state, and the volume of the solder decreases as it solidifies, but no voids are created. That is, a superconducting cable 10 containing no voids can be obtained.

The method for manufacturing the superconducting cable of this example involves twisting a plurality of copper wires that have been tin-plated to improve solder wetting into a rectangular shape, and inserting the twisted wires into a copper gutter immersed in molten solder while vibrating them. At the same time, by gradually taking out the copper gutter from the outlet and cooling the copper gutter from below, it is possible to obtain a void-free superconducting cable.

FIG. 4 is a perspective view showing a method for manufacturing a superconducting cable which is a modification of the method shown in FIG. 3, and the same parts as in FIG. 3 are given the same reference numerals. In this case, the diaphragm 6 of the vibrator is in contact with the presser plate 8,
The entire copper gutter 2 is vibrated to facilitate the floating of air bubbles in the solder 4. This copper gutter 2 is cooled from below by the cooling device 9 to solidify the solder, thereby further reducing voids.

The superconducting cable manufacturing method of this embodiment has the effect of further preventing the generation of voids by vibrating the holding plate at the outlet of the molten solder bath.

The above embodiment describes a method for manufacturing a superconducting cable using a copper gutter with a rectangular cross section, but if a copper gutter with a semicircular cross section is used, the shapes of the outlet 7 and the cooling device 9 should be adjusted accordingly. If so, the same manufacturing method is used. Furthermore, using an ultrasonic device instead of a vibrator to vibrate the copper gutter 2 is effective in expelling air bubbles in the solder over a wider range.

The following cooling device 9 can be used.

(1) A cooling plate made of a copper plate is brought into contact with the lower surface of the copper gutter 2.

(2) Spray water on the bottom of copper gutter 2 to cool it.

(3) Bring the bottom surface of copper gutter 2 into contact with the water surface.

etc., and an appropriate method may be used depending on the shape of the copper gutter 2 and the extraction speed.

Generally, when voids exist in a superconducting cable, the conductivity of heat generated when a current is passed through the stranded wires 1 decreases, and the performance deteriorates. However, when the cable manufactured in the above example was inspected by X-ray flaw detection, no voids were observed and it was confirmed that the cable was excellent. Note that this method can also be used as a continuous manufacturing method for solder embedding materials other than superconducting cables.

The method of embedding a metal wire assembly in a metal gutter with solder according to the present invention has the effect that void-free solder embedding bodies can be continuously manufactured by a relatively simple method.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a stranded wire, Fig. 2 is a cross-sectional view showing the stranded wire of Fig. 1 embedded in a metal gutter with solder, and Fig. 3 is a superconducting wire according to an embodiment of the present invention. FIG. 4 is a perspective view showing a method for manufacturing a superconducting cable, which is a modification of the method shown in FIG. 3. 1...Twisted wire, 2...Copper gutter, 3...Groove, 4...
Solder, 5... Molten solder bath, 6... Frequency, 7...
Output port, 8... Pressing plate, 9... Cooling device, 10...
...Superconducting cable.

Claims (1)

[Scope of Claims] 1. A long metal gutter is submerged in a molten solder tank containing molten solder and has an outlet at one end, and a long metal wire assembly is inserted into the groove of the metal gutter, In the method of embedding the metal wire assembly in the metal gutter with solder, the metal gutter containing the molten solder and the metal wire assembly is continuously taken out from the outlet to solidify the molten solder. After flattening the top surface of the metal gutter with a presser plate installed on the top surface of the outlet,
A method for embedding a metal wire assembly in a metal gutter with solder, characterized in that the metal gutter is cooled from the bottom to solidify the molten solder to prevent voids from forming in the metal gutter. 2. A method for embedding a metal wire assembly in a metal gutter with solder according to claim 1, wherein the holding plate is a plate that vibrates the metal gutter by contacting a diaphragm of a vibrator. 3. The metal wire assembly according to claim 1, wherein the metal wire assembly is a stranded wire that is vibrated by contacting a diaphragm of a vibrator when inserted into a groove of a metal gutter submerged in the molten solder bath. A method of embedding a metal wire assembly into a metal gutter with solder.