JPS5866308A - Manufacture of superconductive coil - Google Patents

Abstract

PURPOSE:To minimize distortion and stress applied to a superconductive wire as much as possible at the time of bending by a method wherein the superconductive wire is previously isolated from a stabilized conductor and bending is separately performed for the stabilized conductor and the superconductive wire. CONSTITUTION:In the initial winding section 3 of a superconductive conductor, a superconductive wire 7 is previously isolated and floated from the groove 8 of a stabilized conductor 5 by the length corresponding to the length l for bending before performing bending. After that, bending is applied to only the conductor 5 isolated the wire 7. Then, the previously isolated wire 7 is inserted along the groove 8 while heating the wire 7 at the solder fusing temperature and is fixed by a soldering layer. At that time, the wire 7 is heated at the solder fusing temperature and furthermore, the wire 7 is thin and under the condition easy for bending. Therefore, the wire 7 is fixed by the soldering layer under the condition that distortion or stress generated in the inside is small even at the time of bending.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a superconducting coil used in a superconducting magnet for a nuclear fusion experimental device, and more particularly to a method for manufacturing a superconducting coil suitable for bending with a small curvature.

In general, small-scale superconducting coils were fabricated by simply winding a round or rectangular wire, which is simply a combination of superconducting wire and a stabilizing conductor, continuously. However, as the scale of equipment increases, the size of superconducting coils is also getting bigger. For this large-scale superconducting coil, it is necessary to use a so-called rectangular superconductor, which is made by drilling or grooving a rectangular stabilizing conductor, embedding superconductor therein, and bonding it with solder.

Conventionally, when manufacturing a coil using a rectangular superconductor in which a superconducting wire is embedded, a coil receiver for setup is prepared with a winding fixed on a plate, and the rectangular superconductor is placed around this winding form.
Wind it sequentially while adding interlayer insulation. As this winding method, edgewise winding or flatwise winding is appropriately selected. The thus wound and bent wire is heated and compressed by a known method, and the superconductor and interlayer insulator are bonded together to complete a pancake coil.

Generally, a plurality of these pancake coils are stacked and the coils are connected by a known method to produce a superconducting coil 1 as shown in FIG. Then, the winding start part 3 and winding end part 4 of the superconductor 2 forming this coil 1 are bent with a bending dimension R1 smaller than the winding dimension R8 of a normal coil to form a current supply terminal part. be.

However, in the conventional manufacturing method, as shown in FIG. In order to bend the superconducting wire 7 embedded through i16 in an integrated state,
This has the problem of causing deterioration of the characteristics of the superconducting wire 7.

That is, when forming the coil 1 by winding the rectangular superconductor 2, the strain and stress that occur during the bending process (edgewise or flat quiz direction) during winding cannot be ignored; This applies harmful strain and stress to the superconductor #7, causing deterioration of the characteristics of the superconducting wire 7, causing quenching of the coil 1 after winding, a decrease in current carrying capacity, and impairing the stability of the superconducting wire 7. There is a problem. In particular, the bending parts near the winding start part 3 and the winding end p part 4, which are the current supply terminals of the coil 1, are bent with a small curvature as described above. The superconducting wire 7 floats in the direction shown by the arrow A, and the solder 1#6 bonding the stabilizing conductor 5 and the superconducting flJ7
This is accompanied by peeling of the solder layer 6 and cracks within the solder layer 6, resulting in deterioration of the characteristics of the superconducting wire 7, quenching of the coil after winding, and reduction in current carrying capacity. These drawbacks are superconductor 2
The smaller the winding dimension R6 and the processing dimension R1 of the winding start portion 3 and the winding end portion 4, the more remarkable this is.

In this way, the superconductor in small superconducting coils is supplied in the form of small round or square wires, so the strain and stress caused by bending is small, causing almost no practical problems. As superconductors become larger, the problem of deterioration of their characteristics due to cracks, strain, and stress has become increasingly apparent.

The present invention focuses on the above-mentioned conventional problems and has developed a superconducting coil using four superconducting coils.
It is an object of the present invention to provide a method for manufacturing a superconducting coil in which the strain and stress applied to the superconducting wire during bending are minimized and the characteristics do not deteriorate.

In order to achieve the above object, the method for manufacturing a superconducting coil according to the present invention involves separating the embedded superconducting wire from the stabilizing conductor in advance at the bending part of the superconductor, and bending and forming only the stabilizing conductor. After that, the superconducting wires that have been separated in advance are reburied and fixed along this bent stabilizing conductor, so that the strain and stress caused by the bending of the stabilizing conductor will not propagate to the superconducting wires. This is to prevent deterioration of the characteristics of the superconducting wire.

Embodiments of the present invention will be described in detail below with reference to the drawings, regarding the case where the winding start portion 3 of the coil 1 is bent.

In the manufacturing method according to this embodiment, the winding start portion 3 that becomes the current supply terminal of the coil 1 is formed by inserting the superconducting wire 7 into the groove 8 formed in the stabilizing conductor 5 through the solder layer 6 immediately before the bending process. It has a rod shape made of embedded superconductors 2.

- At the winding start portion 3 of such a superconductor 2, before bending the superconducting wire 7 from the groove 8 of the stabilizing conductor 5 by the length t (see Figure 1) equivalent to the bending process. It separates and floats. That is, the end of the superconductor 2 is heated to the solder melting temperature by a known method such as high-frequency heating, the solder layer 6 is melted, and the superconducting wire 7 in the groove 8 is gradually heated by four lengths from the end. Lift it up and receive only the length t as shown in FIG. Then, the solder 6 remaining in the groove 8 of the stabilizing conductor 5 is carefully cleaned.

Thereafter, only the stabilized conductor 5 from which the superconducting wire 7 has been separated is bent using a bender or the like. The stabilizing conductor 5 may be bent by an amount corresponding to the amount of bending required by the winding start portion 3.

After that, the opening dimensions of the groove 8 were manually corrected and adjusted.
The superconducting wire 7 separated in advance along this groove 8 is inserted while being heated to the solder melting temperature using high frequency heating or the like.
It is fixed again by the solder layer 6. At this time, superconducting #i!
7 is heated to the solder melting temperature and is thin and easy to bend, so it is re-fixed by the solder layer 6 with little strain or stress generated inside when it is bent. be done.

After the superconducting fm7 is embedded in the groove 8 and re-fixed in this way, the lid 9 is attached to the opening of the groove 8 and the opening is sealed, thereby completing the bending process.

As described above, according to this embodiment, the superconducting wire 7 is separated from the stabilizing conductor 5 in advance, and the bending process is performed on the stabilizing conductor 5,
Since the bending is performed separately on the superconducting wire 7, the strain and stress caused by directly bending the superconductor 2 are prevented from being propagated to the superconducting wire 7, as in the conventional method. Therefore, defects such as deterioration of characteristics of the superconducting wire 7 and reduction in current capacity can be improved. In particular, since the strain and stress on the superconducting wire 7 caused by the bending process when reattaching it to the groove 8 are very small, it is possible to manufacture a superconducting coil 1 with excellent characteristics. In addition, portions with complex shapes where abnormal strain or stress occurs during bending can be processed in the same manner, so that no deterioration of characteristics occurs.

As described above, according to the present invention, it is possible to minimize the strain and stress applied to the superconducting wire during bending, and it is possible to manufacture a superconducting coil that does not suffer from characteristic deterioration.

[Brief explanation of the drawing]

Figure 1 is a plan view of the superconducting coil, Figure 2 is a partial sectional view of the superconductor, Figure 3 is a perspective view showing the superconducting wire separated from the stabilizing conductor, and Figure 4 is the superconductor after re-fixation. FIG.

Claims (1)

[Claims] 1. B made by embedding and fixing superconducting wires in a stabilizing conductor
In a method of manufacturing a superconducting coil by winding a conductor,
The embedded superconducting wire is separated from the stabilizing conductor in advance at the bending part of the superconductor, such as the winding start part and the winding end part of the superconducting coil, and only the stabilizing conductor is bent and formed. A method for manufacturing a superconducting coil, comprising reburying and fixing the separated superconducting wire along a stabilizing conductor.