JPS6022304A - Superconductive wire for winding - Google Patents

Abstract

PURPOSE:To prevent damage on an insulative film and shor-circuit of a layer during pressure molding by providing between a superconductor and its insulative film a metallic film of hardness equivalent to the medium value of hardness of the former. CONSTITUTION:A superconductor 14 is coated with a thin-film aluminium layer 22 of high purity and the exterior of the aluminium layer 22 is coated with a dual copper-coated layer 24. In addition, polyimido film or aromatic polyamido film prepregnated with prepreg resin is taped or coated on the surface of the copper-coated layer 24 thus forming an insulating material 26. On the exterior of the insulating material 26, an outer circumferential wire insulative layer 30 is provided. The occurrence of short-circuit in the layer can be chekced by preventing damage on the insulative layer through the plastic deformation of the aluminium layer and also the copper layer during the pressure molding of winding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a superconducting wire suitable for forming a superconducting magnet.

[Background of the invention]

FIG. 1 shows an example of a winding for a superconducting magnet. The superconducting winding 10 includes several hundred superconducting wires 12.
It is formed by winding. The conventional superconducting wire 12 is
As shown in FIG. 2, the surface of the rectangular superconducting conductor 14 is coated with an insulating layer 1'6.18. This insulating layer 16.18
The superconducting conductor 14 is formed by enameling the entire surface of the superconducting conductor 14, or by doping a polyimide film or a polyamide film on the top of the surface 1 of the superconducting conductor 14. Then, the superconducting wire 12 provided with the insulating layers 16 and 18 is wound in an aligned manner as shown in FIG. It is common to completely fill the gaps between each insulating layer (Toshiba Shibu Vol. 36 No. 7 [
Floating superconducting magnet for railways], Special Publication 1984-184
Publication No. 19).

The molding resin used is epoxy, polyester, or polyvinyl formal, which has relatively good cryogenic properties, and has excellent injection and mold ink properties.

Research to compactly achieve a high magnetic field in superconducting magnets can be found in, for example, ``Superconducting technology supporting ultra-large accelerators'' (published by Science Museum ■0m23°A216.198
As can be seen in the July-August issue of 2016, written by Hiromi Hirabayashi, this is an important theme that must be achieved in the development of nuclear fusion devices. Superconducting magnet windings are compact and generate high magnetic fields, but due to the high magnetic fields and high-density currents generated during operation, the windings themselves experience stress several times higher than conventional magnets. Therefore, even if the superconducting wire has high performance, if the formed winding has low structural rigidity, a so-called quench phenomenon occurs and the wire becomes normal conductive, making it impossible to obtain a high magnetic field. Therefore, in order to improve the rigidity of the winding, the insulating layer applied to the superconducting wire is made as thin as possible, and in order to reduce the microscopic movement of the wire itself formed in the winding, it is necessary to The winding is formed while applying a load in advance.

When the winding is formed while applying a load in this manner, the rigidity of the winding is increased, and the magnetic field that can be generated can be further increased as shown in FIG. However, conventional superconducting conductors and insulation configurations have a drawback that insulation short circuits between conductors are likely to occur when the above-described pressure molding is performed. That is, when the wire is wound, the wire becomes deformed, meandering, or tilted, and the corners of the superconducting conductor tend to damage the insulating layer during pressure molding.

[Purpose of the invention]

The present invention has been made in order to eliminate the drawbacks of the prior art, and an object of the present invention is to provide a superconducting wire tube for winding that can prevent layer shorts in pressure-molded winding wire.

[Summary of the invention]

The present invention interposes a metal film between a superconducting conductor and an insulating film covering the surface of the superconducting conductor, and the metal film has a hardness intermediate between that of the superconducting body and the insulating film. The structure is such that it can be plastically deformed to prevent damage to the insulating coating and prevent layer shorts from occurring.

[Embodiments of the invention]

Preferred embodiments of the superconducting wire for winding according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 is a partial cross-sectional view of a superconducting winding formed using the superconducting wire according to the invention before pressure molding, and the thickness of 22 is:
The thickness of the copper coating film 24 is preferably 0.1 to 0.3 mm for general superconducting conductors, and the thickness of the copper coating film 24 is 0.1 to 0.2 rtm.
is preferable, but the thickness is increased or decreased depending on the dimensions of the superconducting conductor 14.

Further, a conductor insulating material 26 serving as main insulation is provided on the surface of the copper coating film 24. This conductor insulating material 26 is made of a polyimide film or an aromatic polyamide film that has been prepreg-treated with a prepreg resin 28 and a copper coating layer 24.
The surface is taped or coated.

An outer wire tension insulation layer 30 is provided on the outer periphery of the conductor insulation material 26. This outer wire insulating layer 3o is provided by winding or inserting a cross-shaped or roving-shaped tape made of hard fibers such as aromatic polyamide, glass, or carbon.

The superconducting wires formed as shown in Figure 2 are arranged and wound to form a winding wire, as shown in a partial cross section of FIG. This winding is then subjected to pressure molding, which is the final process.

This pressure molding is performed as follows. First, as shown in FIG. 5, from the X direction and the Y direction of the superconducting winding 10, 0.
5, the pressurizing force is increased every 2 seconds, and a pressure of 3 Ky/m2 is applied to the superconducting winding 10. That is, 0.
Apply a pressure of 97 mm2 to 5, then apply a pressure of 0.51 (q / lan 2) in the Y direction while maintaining the pressure in the X direction. Then, while maintaining the pressure in the Y direction, increase the pressure in the X direction. is increased by 0.5 Kg/1ran2 to 1.OKy/mm2.

After the superconducting coil 10 is pressurized at room temperature at 3K9/1ran'' from the X and Y directions in this way, the temperature of the whole is raised to 80C in 20 to 25 minutes, as shown in Figure 6. Then, in this 80c, 10~
After maintaining the temperature for 15 minutes, the pressure applied to the superconducting winding 10 is increased and the temperature is increased. This pressurization is
Depending on the magnitude of the magnetic field generated by the superconducting winding lOF)
Can be selected to any value of 20 Kg/rtvn2,
For example, as shown in Fig. 6, the pressure is increased in steps of 1 Kg/m2 in the same manner as above, and the pressure is finally increased to 8 Kg/mm2.Then, as the pressure increases, the forming temperature is gradually increased. This temperature rise is done so that the set temperature reaches the final stage when the set pressure rise of pressurization reaches the final stage.
It is preferable to set the increase in pressure and the rate of increase in temperature. In addition, the molding temperature is generally set at around 1000C, but may vary from 100 to 180C depending on the properties of the prepreg resin.
Choose the appropriate temperature.

In this way, the superconducting winding 10 is maintained at a predetermined temperature for a certain period of time until the resin hardens while pressure is applied to the superconducting winding 10. During this time, the prepreg resin fills the gap between the superconducting wires and flows out of the superconducting winding 10.
The volumetric dimensions of superconducting winding 10 are reduced. Then, the glass or carbon fiber forming the outer wire insulation layer 30 bites into the conductor insulation material 26 and sinks into the conductor insulation material 26, acting in the same way as a composite material and improving rigidity. do. Furthermore, when the superconducting wire 12 is wound in a meandering or inclined state, the thin film aluminum layer 22 coated around the superconducting conductor 14 is plastically deformed as shown in FIG. We will be able to get closer to each other.

In addition, the thin film copper layer 24 prevents the plastically deformed thin film aluminum layer 22 from flowing out of the insulating layer, and a part of the thin film copper layer 24 partially moves to close the corner between the superconducting wires 12. Fill.

The superconducting good wire 10 is maintained at high temperature and high pressure to completely cure the resin, and once the resin is completely cured, the superconducting winding 10
The temperature is lowered to room temperature while maintaining the pressure applied to the superconducting winding 10, and the pressure applied during shaving when the temperature of the superconducting winding 10 reaches room temperature is removed.

The superconducting winding 10 molded in this way is shown in FIG.
As shown by the dashed dotted line, the dimensions of the completed winding are smaller than the integrated value of the base material thicknesses of the respective constituent materials, making it possible to create a compact and high-density superconducting winding 10. Moreover, even if the superconducting conductor 14 is wound in an inclined state as shown in FIG. 7, the superconducting winding 10 can be manufactured without layer short-circuiting due to the plastic deformation of the thin film aluminum layer 22 and the thin film copper layer 24. can do. Therefore, the manufacturing yield of the superconducting winding 10 is significantly improved, and a superconducting magnet winding with excellent performance can be manufactured at low cost. Moreover, as shown in FIG. 8, by applying high compression pressure to the superconducting winding 10, the finished dimensions of the windings and glands can be reduced, and the elastic modulus of the winding as a whole can be reduced by l.
X10"K7/α2 or more, and high rigidity can be achieved. Therefore, the magnetic field generation ability can be improved by 10 to 20% compared to the conventional method.

In order to obtain a high-density winding wire as described above, it is necessary to make the dimensions of the molding layer much smaller than the integrated standard value of the base material dimensions. And the highly rigid superelectric 4y winding 1
In order to obtain 0, the thickness of the fibrous cross tape forming the outer wire insulation layer 30 must be 30 times the thickness of the conductor insulation material 26.
It is desirable to set it to ~65 inches. In addition, the volumetric space factor in the thickness direction of the fiber cloth tape constituting the outer wire insulation layer 30 before pressurization, that is, as the original material, is 30 to 30.
It is desirable to select one with 45 inches.

If the volume space ratio exceeds 45%, the conductor insulation material 26 is likely to be torn off when the fibers bite into the conductor insulation material 26. For materials, the effect of improving rigidity is reduced.

In the above embodiment, the metal film coated around the superconductor 475 body 14 is the thin aluminum layer 22. It is possible to use a material that can alleviate mechanical damage and destruction of the insulating material due to partial unbalanced loads during high-temperature molding. Further, the insulating material may be inserted, taped, etc. when winding the wire.

〔Effect of the invention〕

As explained above, according to the present invention, a metal film that is softer than the superconducting conductor is interposed between the superconducting conductor and the insulating film surrounding the superconducting conductor, thereby preventing layer shorts during winding forming. Occurrence can be prevented.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a superconducting winding, Fig. 2 is a partial sectional view of a conventional superconducting winding, Fig. 3 is a diagram showing the relationship between the stiffness of the winding and the magnitude of the magnetic field that can be generated, and Fig. 4 The figure is a partial sectional view of a superconducting winding using the superconducting wire for winding according to the present invention, FIG. 5 is an explanatory diagram of the pressurizing method in pressure forming of the winding, and FIG. 6 is the implementation of winding forming. An explanatory diagram of an example, FIG. 7 is a partial cross-sectional view of a superconducting winding after molding using the superconducting wire for winding according to the present invention, and FIG. 8 is a dimensional ratio of the base material thickness of the winding to the integrated value. It is a figure showing the relationship between and compressive elastic modulus. 10... superconducting winding, 12... superconducting wire, 14.
...Superconducting conductor, 16.18...Insulating layer, 22...
Thin film aluminum layer, 24... Thin film copper layer, 26...
Conductor insulating material, 30... outer periphery wire insulating layer. Agent Patent Attorney Tatsuyuki Unuma No. 1 Country No. 2 Figure/8 Hou 3 Mooka “1 I. Raw kVc A.

Claims (1)

[Claims] 1. A superconducting wire for winding comprising a linear superconducting conductor and an insulating coating covering the superconducting conductor, in which a metal that is softer and cheaper than the superconducting conductor is provided between the superconducting conductor and the insulating coating. A superconducting wire for winding characterized by having a film interposed therein. 2. The superconducting wire for winding according to claim 1, wherein the metal film is formed of aluminum with a thin copper layer on the side of the insulating coating, and the insulating coating is a prepreg.