JPS6112351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conductor connecting device, and particularly to a connecting device suitable for connecting superconducting coils.

As is well known, a superconducting coil is cooled to an extremely low temperature (for example, liquid helium temperature of 4.2 K) and becomes a perfect conductor, that is, a superconducting state. Figure 1 shows an example of a schematic diagram of the superconducting coil. In the figure, 1a to 1n are superconducting coils. The superconducting coils 1a to 1n are connected to power leads 2a and 2b, and adjacent coils are connected to each other by connecting portions 4a to 4m. A portion of these superconducting coils 1a to 1n, connection parts 4a to 4m, and power leads 2a and 2b are sealed in a cooling medium tank 5, and a cooling medium such as liquid helium is injected into the tank. . The cooling medium tank is thermally insulated by a vacuum tank 6. The liquid helium is gradually vaporized by the Joule heat generated from the power leads 2a, 2b and the connection parts 4a to 4m and the heat entering the cooling medium tank 5. In order to prevent this from increasing the pressure within the cooling medium tank 5, an exhaust pipe 7 is provided to exhaust the vaporized helium gas to the outside. A liquid helium injection pipe 8 is also provided for supplementing the insufficient liquid helium.

FIG. 2 shows a conventional superconducting coil connection section 30. As shown in FIG. The superconducting wire 11 of the superconducting coil has one side (flat surface) with the superconducting wire 12 of the adjacent superconducting coil.
It is joined by solder.

FIGS. 3 and 4 show connections 31 and 32 between superconducting coils as prior art. In FIG. 3, the superconducting wire 11 of the superconducting coil is first joined to the copper block 41 by solder. Next, these copper blocks 41 and 42 are joined by solder, as shown in FIG. 3b, with the superconducting wires facing each other.

Figure 4 shows a copper block 4 similar to the configuration shown in Figure 3.
3 and 44 are joined by solder so that the superconducting wires 11 and 12 face each other, and are further tightened with bolts and nuts 50 to increase the joint strength of the joint surfaces.

These conventional and prior art connections between superconducting coils are made by directly soldering superconducting wires on one side to another, or superconducting wires soldered to copper blocks in order to increase the contact area, and using current I is the tangent section 3 from the superconducting wire 11
0, 31 or 32 to the other superconducting wire 12. The connection part has the role of passing current, but when connecting superconducting wires, it is necessary not only to simply pass current, but also to have the following functions and operations. That is, since the superconducting wire connection portion is not in a superconducting state, Joule heat is generated. If the amount of heat generated by this unit is large, a large amount of liquid helium will vaporize and the temperature of the connection will rise.
This not only causes instability of the superconducting coil, but also sometimes causes damage to the power leads 2a, 2.
b and the superconducting coils 1a to 1n may even be burnt out. For this reason, it is necessary for the superconducting wire connection portion to have a large connection area and to have a function of suppressing Joule heat generation.

The conventional superconducting coil connection section 30 is configured to directly solder one side of the superconducting wires to each other, so in order to reduce the connection resistance of the solder joint section, it is necessary to have a considerable length (10KA class conductor). However, the disadvantage was that it required soldering over a length of several meters.

Therefore, as a prior art, a superconducting coil connection section having a structure as shown in FIGS. 3 and 4 has been considered. The connection parts 31 and 32 have a large connection area,
Although this was an attempt to reduce the connection resistance, both of these connection parts 31 and 32 are connected to the copper block 4.
Since 1-42 and 43-44 are joined with solder, it is inconvenient to remove the connection part, and it is troublesome to replace the electromotive conductive coil.Also, in order to obtain a sufficiently large connection area, even if a copper block is used, it is difficult to remove the connection part. Even if it is used, it has disadvantages such as requiring a large size and being unsuitable for use in a small space.

This invention was made in order to eliminate the drawbacks of the connections between superconducting coils according to the conventional and prior art techniques as described above, and it simplifies the connection method using only bolts and nuts, making removal work easier. The object of the present invention is to provide a connection device with a lower connection resistance by increasing the connection area and obtaining a larger connection area with a copper block of the same volume.

An embodiment of the present invention will be described below.
In FIGS. 5a and 5b, 45 and 46 are copper blocks, and each block has a superconducting wire 11 of a superconducting coil or a superconducting wire 12 of an adjacent superconducting coil, and the upper surface of each block is an adjacent part thereof. The copper blocks 45 and 46 are buried so as to be flush with the upper surfaces, that is, the joining surfaces, and the buried portions are joined and integrated by soldering.

One of the copper blocks 45 shown in FIG.
After the superconducting wire 12 is soldered, the superconducting wire 1
An indium material 60 is integrated with the copper block 45 by soldering the entire surface of the copper block 45 to the copper block 46 so that the indium material 60 is sandwiched therebetween.

The surface of the other block 46 shown in FIG. 5B on the side to which the superconducting wire 11 is soldered is knurled (or cut) so that many small pyramid-shaped protrusions protrude.

FIG. 6 shows a state in which the two blocks shown in FIGS. 5a and 5b are joined with bolts and nuts 51.

In FIG. 6, the small protrusion of the copper block 46 completely pierces the indium material 60 on the side of the copper block 45, thereby causing the copper block 4
The joint portion 33 between 5 and 46 is increased to reduce the connection resistance. At the same time, since the two copper blocks 45 and 46 are joined only by bolts and nuts 51, the connecting portion 33 can be easily removed. Further, if the indium material 60 becomes damaged due to repeated removal, it is sufficient to replace only the indium material 60.

As a result of the above, the work of removing the connection part 33 becomes easy, and the amount of heat generated by the coil is reduced due to the increase in the connection area, so that instability of the coil and burnout of the power lead coil will not occur. Further, there are effects such as reducing the amount of cooling medium consumed.

In the above example, indium material 60 was used for the joint surface of the copper block, but this metal plate may be made of other metals that are softer than copper, which have good electrical conductivity. good. Further, in the above embodiment, the case of the connection section 30 between superconducting coils was explained, but it may also be used for the connection sections 3a, 3b between the power leads 2a, 2b and the superconducting coils 1a, 1n as shown in FIG. , has the same effect as the above embodiment.

As described above, according to the present invention, the superconducting coil connection part has a simple structure in which the connection is tightened with bolts and nuts, and the connection area is increased by combining a large number of protrusions with a metal that is softer than the protrusions. Since the configuration is aimed at, the connection between the superconducting coils can be made compact, and the connection and disconnection work can be facilitated and the work time can be shortened. Furthermore, since the Joule calorific value is small, it has great practical effects, such as being able to reduce the consumption of expensive cooling media.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the surroundings of a superconducting coil device, FIG. 2 is a perspective view showing a conventional connection between superconducting coils, and FIGS. 3 and 4 show the configuration of a connection between superconducting coils according to the prior art. FIG. 5 is a perspective view showing a connection between superconducting coils according to an embodiment of the present invention, and FIG. 6 is a perspective view showing a connection between superconducting coils according to an embodiment of the present invention. be. In the figure, 1a to 1n are superconducting coils, 4a
-4m, 31, 32, 33 are connections between superconducting coils, 11, 12 are superconducting wires, 51 is a bolt/nut, 60 is an indium material, and 41 to 46 are copper blocks. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A first conductor, which is one conductor of the conductors to be connected, is buried so that its upper surface is flush with an adjacent part, and the buried part is soldered and connected to the first conductor. At the same time, a soft metal with good electrical conductivity and softer than copper is soldered to the entire joint surface with the second copper block to sandwich the first conductor. A copper block is provided with a large number of protrusions on its joint surface with the first copper block, and the top surface of the second conductor, which is the other conductor to be connected to the joint surface, is almost flush with the adjacent surface. a second copper block which is buried in the same way and integrated with a second conductor by soldering and joining the buried portion;
and bolts and nuts for tightening the first copper block so that the soft metal surface of the first copper block and the protrusion-arranged surface of the second copper block are aligned and the protrusions sufficiently bite into the soft metal surface. A conductor connecting device characterized by: 2. The conductor connection device according to claim 1, wherein the first conductor is a superconducting conductor. 3. The conductor connection device according to claim 1 or 2, wherein the second conductor is a superconducting conductor. 4. The conductor connection device according to any one of claims 1 to 3, wherein the soft metal material is an indium material. 5. The conductor connection device according to any one of claims 1 to 3, wherein the large number of protrusions are protrusions formed by knurling or cutting.