JPH06150992A - Connecting structure for superconducting wire - Google Patents

Abstract

PURPOSE:To reduce pulse loss of a connection section in the fluctuating magnetic field while keeping Joule's heat in a stationary magnetic field at the level not hindering the operation of a superconducting magnet. CONSTITUTION:High-resistance layers 31 made of a material having the electrical resistivity higher than that of solder 4 are provided on the outer peripheries of strands 2 of a connection section so that the coupling current flowing between the strands 2 during the pulse operation is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used, for example, in the case of connecting a plurality of windings to produce a superconducting coil.
The present invention relates to a superconducting wire connection structure in which parts to be connected to each other are connected using a brazing material such as solder.

[0002]

2. Description of the Related Art FIG. 39 shows, for example, "11th INTERNATIONAL CONFERENCE ON Magnet Te
chnology) "(1989) pages 847-851, showing a conventional superconducting wire connection structure.
FIG. 40 is a sectional view of the connection portion of FIG. 39. In the figure, 1 is a superconducting wire formed by assembling and twisting a large number of strands 2.

Reference numeral 3 denotes a connecting portion which connects the portions to be connected of the two superconducting wires 1 to each other. The connecting portion 3 electrically connects the wires 2 of the portions to be connected by a lead-tin solder 4. It is done. Reference numeral 5 denotes a copper protective case having a U-shaped cross section, which is provided on the outer peripheral portion of the connection portion 3, and is for protecting the solder 4 when the connection work is performed.

Next, the operation will be described. Superconducting wire 1
The connection part 3 and the connection part 3 are used after being cooled to a cryogenic temperature of about −267 ° C. by a coolant such as liquid helium. Since the superconducting wire of the cooled superconducting wire 1 is in the superconducting state,
Allows current to flow without resistance loss. Due to such properties, the superconducting wire 1 is often wound and used as a superconducting magnet.

When this superconducting magnet is manufactured, the superconducting wire 1 has a finite length and is structurally restricted, so that the connecting portion 3 as described above is always required at several places. There are various methods for connecting the superconducting wire 1, but connection by the solder 4 is the most general method. Particularly, it is often used when a large current exceeding 1000 A is passed.

Normally, the solder 4 is a normally conductive substance in a magnetic field of 0.1 Tesla or more, so that when a current flows through the solder 4, Joule heat is always generated. However, the electric resistivity of the solder 4 at a very low temperature is as small as about 7 × 10 ^-9 Ωm, and the example of the above-mentioned connection portion 3 shows a connection resistance of 1.4 × 10 ^-10 Ω. This resistance value is such that about 0.1 W of Joule heat generation (DC electric resistance loss) occurs when a rated current of 30 kA flows, and is a sufficiently small value that does not hinder the operation of the superconducting magnet.

Next, FIG. 41 shows, for example, Japanese Patent Laid-Open No. 3-8490.
FIG. 42 is a front view showing the connection structure of the conventional superconducting wire shown in Japanese Patent Publication No. 3, a perspective view showing an enlarged main part of FIG. 41, and FIG. 43 is a sectional view for explaining the configuration of the superconducting wire of FIG. Is. In the figure, 11 is a superconducting wire (parent twisted wire), one of which is 11a and the other is 11b. 12 is a superconducting wire 11
Is a superconducting wire that constitutes the child twisted wire 12, and as shown in FIG. 43, the superconducting wire 11 has a double twisted wire structure as a whole.

In the connection structure shown in FIG. 41, the superconducting wire 1
The parts to be connected to each other are decomposed into the child twisted wires 12, and the child twisted wires 12 are soldered to each other to form the connection portion 14. In the connection portion 14, the two child twisted wires 12 to be connected are accommodated in a sheath 15 made of copper and having a U-shaped cross section, and the sheath 16 is filled with solder 16 to form a unit connection as shown in FIG. The part 17 is configured.

Next, the operation will be described. When the superconducting coil (superconducting magnet) having the above-described connecting portion 14 is pulse-operated, the magnetic field generated changes according to the change of the energizing current. That is, the energizing speed is 100%
The current is started up in a time of 1 to several seconds, and if this is used as the rate of change of the magnetic field, it becomes 1 to several tesla per second. When the superconducting coil is used under such fast fluctuation conditions,
Pulse loss heat (AC loss heat) is generated inside the superconducting wire 11 due to a coupling current and an eddy current, and loss due to evaporation of helium as a refrigerant occurs. Further, the temperature of the superconducting coil rises due to the pulse loss heat itself, the superconducting state cannot be maintained, and the operation is stopped by so-called quench.

On the other hand, the superconducting wire 11 itself is thinned so that the heat generated by such rapid current change and magnetic field fluctuation is minimized, and the structure inside the superconducting element wire 13 is also lost. It is possible to make a structure with less. However, it is difficult to suppress the pulse loss because the highly conductive metal portion becomes thick in the connection portion 14.

Such pulse loss can be considerably reduced by reducing the size of the conductor in the direction orthogonal to the magnetic field. The connection structure shown in FIG. 41 is
It is intended to reduce the pulse loss in the connecting portion 14, reduce the number of unit of the superconducting wire connected in the connecting portion 14, and subdivide the thickness of the metal portion into small pieces, thereby making the conductor dimension in the direction perpendicular to the magnetic field. To reduce the pulse loss heat generation.

As described above, in the above-mentioned connection structure, the twisted pair wire 12 must be bent and extended at the time of forming the superconducting wire 11 so that the superconducting wire 11 can be assembled in a nested shape. Such processing is possible in a superconducting coil using an NbTi superconducting wire which is a superconducting wire for low magnetic fields. However, in the superconducting coil using the Nb ₃ Sn superconducting wire which is the superconducting wire for high magnetic field, as shown in FIG. 44, only a slight bending strain of about 0.5% is applied, and Since the superconducting property (superconducting critical current) is significantly reduced, N
It is not possible to separate the superconducting wires 11 into individual twisted wires 12 or to combine the separated twisted wires 12 together in a nested manner after the b ₃ Sn formation heat treatment. Therefore, Nb
_When using a 3Sn superconducting wire, the superconducting wire 11 is carefully separated into a bundle of two to three sets of twisted wires 12 and connected.

Here, the procedure for producing a large-sized superconducting coil for a high magnetic field using Nb ₃ Sn superconducting wire will be described. First, a pancake coil is manufactured in a non-heat-treated state, and then heat-treated to generate Nb ₃ Sn.
Then, after performing insulation work in a pancake state, a required number of pancake coils are stacked and the conductor ends of the pancake coils 18a and 18b are connected to each other, as shown in FIG. After this, the whole pancake-shaped coil laminated in multiple layers is subjected to insulation treatment again.

Next, FIG. 46 is a sectional view of a conventional forced cooling type superconducting wire shown in, for example, "Fusion Technology 1990" (published by North Holland, 1991), page 243, and FIG. 47 is a superconducting wire of FIG. It is a block diagram which shows the connection structure of. In the figure, 21 is a strand (superconducting strand),
22 is a primary stranded wire in which 9 strands of wire 21 are twisted together, and 23 is 1
It is a secondary twisted wire in which 17 secondary twisted wires 22 are twisted around a core 24.

25, 25a and 25b are conduits, which are structural members surrounding the secondary twisted wire 23, and 26a and 26b.
Are cooling channels arranged on both sides of the secondary twisted wire 23 in the conduit 25.
a and 26b have a substantially C-shaped cross section, and the secondary twisted wire 2
It has a refrigerant flow passage opening to the 3 side. 27a, 27
b is a connecting part twisted wire, 28 is a connecting part twisted wire 27a, 27
connection part structural member holding b, 29 is solder, 30
Is a connection part cover.

Next, the operation will be described. The forced cooling type superconducting wire as described above has a large current capacity and high strength. That is, a large number of wires 21 are twisted together to increase the current capacity, and the whole is covered with a conduit 25 to increase the strength. Conduit 25
Serves as a structural member for supporting the electromagnetic force of a superconducting coil (not shown) wound with the forced cooling type superconducting wire, and prevents the refrigerant flowing in the cooling channels 26a and 26b from leaking out of the conduit 25. It has the function of keeping airtightness.

Further, the cryogenic and high pressure supercritical helium which is a refrigerant is pressure-fed into the spaces inside the cooling channels 26a and 26b and the secondary twisted wire 23 to cool the wire 21. At this time, since the above-described forced cooling type superconducting wire is composed of many thin wires 21, the cooling surface area is large,
It also has the feature of excellent cooling characteristics.

Next, the connection method will be described. In the forced cooling type superconducting wire as described above, as shown in FIG. 47, the secondary twisted wire 23 is formed into connection twisted wires 27a and 27b, and the connection twisted wire 27a is connected to the connection twisted wire 27b. The connecting portion structural member 28 having a U-shaped cross section
Then, the solder 12 is filled and connected. Secondary stranded wire 23
After connecting the parts to each other, a connecting part cover 30 is attached to keep the connecting parts airtight and welded to the conduits 25a and 25b.

[0019]

In the conventional superconducting wire connection structure as shown in FIGS. 39 and 40, the loss due to electric resistance (joule) in a state cooled in a stationary magnetic field is as follows. (Heat generation) can be suppressed and current can be supplied, but when a fluctuating magnetic field is applied from the outside or when the coil current is fluctuated, pulse fluctuation is caused by the fluctuating magnetic field generated in the connection part 3. The heat of several W to several 100 W is sometimes generated in the connecting portion 3.

That is, during pulse operation, an unnecessary coupling current flows between the wires 2 of the connecting portion 3 from which the insulating layer has been removed, and the pulse loss due to this coupling current becomes considerably larger than that in steady heat generation. If the amount of generated heat is large, the temperature of the connecting portion 3 rises, which not only causes the instability of the superconducting magnet, but in some cases, the superconducting wire 1 of the connecting portion 3 shifts to the normal conducting state. There was a problem that the operation of the superconducting magnet stopped.

Further, in the conventional connection structure of the superconducting wire 11 as shown in FIGS. 41 to 43, the superconducting wire 11 is subdivided into child twisted wires 12 units. However, there was a problem that the reduction was insufficient. In particular, when a compound superconducting wire such as Nb ₃ Sn is used, it is difficult to subdivide the superconducting wire 11 as described above, so that there is a problem that the pulse loss in the connecting portion 14 becomes large.

Furthermore, in the conventional forced cooling type superconducting wire connection structure as shown in FIG.
Since 7b is a superposed structure, there is a problem that the connecting portion becomes spatially large. Further, since a large number of strands 21 are handled at once, workability is poor and there is a problem that the superconducting wire may be damaged. In particular, when a compound-based superconducting wire, such as Nb ₃ Sn, whose characteristics are greatly deteriorated by strain is used, there is a problem that the superconducting characteristics of the connection portion are greatly deteriorated.

The present invention has been made to solve the above-mentioned problems, and it is possible to maintain Joule heat generation in a steady magnetic field at a level that does not hinder the operation of the apparatus, while in a fluctuating magnetic field. It is an object of the present invention to obtain a superconducting wire connection structure capable of reducing the pulse loss of the connection part in the. Another object of the invention is to obtain a superconducting wire connection structure that is spatially compact and easy to handle.

[0024]

According to a first aspect of the present invention, there is provided a superconducting wire connecting structure, wherein a superconducting wire connecting structure is provided on an outer circumference of a wire to be connected.
A high resistance layer made of a material having an electric resistivity higher than that of the brazing material is provided.

According to a second aspect of the present invention, there is provided a superconducting wire connecting structure in which a high resistance plating layer made of a metal having a higher electric resistivity than that of a brazing material is plated on the outer circumference of the wire to be connected. .

In the superconducting wire connection structure according to the third aspect of the present invention, a high resistance film made of a metal having a higher electric resistivity than the brazing material is wound around the outer circumference of the wire to be connected.

In the superconducting wire connection structure according to the invention of claim 4, a high resistance sheath made of a metal having a higher electric resistivity than the brazing material is covered on the outer periphery of the wire to be connected.

According to a fifth aspect of the present invention, there is provided a superconducting wire connecting structure, which is a high resistance modified material obtained by modifying a stabilizing material for a wire to be connected so as to have a higher electric resistivity than a brazing material. The quality layer is formed.

According to a sixth aspect of the present invention, there is provided a superconducting wire connection structure in which a metal material is diffused from an outer peripheral surface of the element wire into a material for stabilizing the element wire to be connected so that the electric resistance is higher than that of the brazing material. The high-resistance reformed layer is modified so that the rate is high.

According to a seventh aspect of the present invention, there is provided a superconducting wire connecting structure in which a metal material is diffused from an end portion of an element wire into a material for stabilizing an element wire to be connected so that the electric resistance is higher than that of a brazing material. The high-resistance reformed layer is modified so that the rate is high.

In the superconducting wire connection structure according to the invention of claim 8, each superconducting wire of a portion to be connected is subdivided into a plurality of dividing lines arranged linearly in cross section, and a cross section of the entire connecting portion. The shape is rectangular, and a high-resistance metal interposer made of a metal having a higher electric resistivity than the brazing material is arranged between the adjacent dividing lines.

According to a ninth aspect of the present invention, there is provided a superconducting wire connection structure, wherein each superconducting wire of a portion to be connected is subdivided into a plurality of dividing lines arranged linearly in cross section, and a cross section of the entire connecting portion. A high resistance metal made of a metal having a higher electrical resistivity than a brazing filler metal between adjacent connection units, which has a rectangular shape and is composed of a plurality of dividing lines arranged in the direction of the magnetic field. An interposer is arranged.

According to a tenth aspect of the present invention, there is provided a superconducting wire connection structure, wherein each superconducting wire in a portion to be connected is subdivided into a plurality of dividing lines arranged in a circular cross section, and each superconducting wire is divided. By alternately arranging the wires, the entire connecting portion is formed into a cylindrical shape, and between the adjacent dividing lines, a high resistance metal intercalation material made of a metal having an electric resistivity higher than that of the brazing material is arranged.

In the superconducting wire connection structure according to the eleventh aspect of the present invention, each superconducting wire of a portion to be connected is subdivided into a plurality of dividing lines arranged in a circular cross section, and one of them should be connected. By arranging the parting line of the other connecting part on the outer side in the radial direction of the parting line, the whole connecting part is made cylindrical, and the electrical resistivity between the adjacent parting lines is higher than that of the brazing material. A high resistance metal interposer made of metal is arranged.

In the superconducting wire connection structure according to the twelfth aspect of the present invention, each superconducting wire of a portion to be connected is subdivided into a plurality of dividing lines arranged in a circular cross section, and each superconducting wire is divided. By alternately arranging the wires, the entire connecting portion is formed into a columnar shape, and between the adjacent dividing lines, a high resistance metal interposer made of a metal having a higher electric resistivity than the brazing material is arranged.

In the superconducting wire connection structure according to the thirteenth aspect of the present invention, each superconducting wire of a portion to be connected is subdivided into a plurality of dividing lines arranged in a circular cross section, and one of them should be connected. By arranging the parting line of the part that should be the other connecting part on the outer side in the radial direction of the parting line, the whole connecting part is cylindrical, and the electrical resistivity between the adjacent parting lines is higher than that of the brazing material. A high resistance metal interposer made of metal is arranged.

According to a fourteenth aspect of the present invention, there is provided a superconducting wire connection structure, wherein each superconducting wire of a portion to be connected is thinned into a plurality of dividing lines, and each dividing line is inserted into a metal pipe. To form a sub-structure, and the sub-structure on one side and the sub-structure on the other side are butt-joined with a soft brazing material, and adjacent sub-structures are also joined with a soft brazing material. It was done.

According to a fifteenth aspect of the present invention, there is provided a superconducting wire connection structure, wherein each superconducting wire of a portion to be connected is thinned into a plurality of dividing lines, and each dividing line is inserted into a metal tube and heat fusion is performed. To form a sub-structure, and further butt-join the sub-structure on one side and the sub-structure on the other side with a soft brazing material, and join the adjacent sub-structures with each other with a soft brazing material. Is.

According to a sixteenth aspect of the present invention, there is provided a superconducting wire connection structure, wherein each superconducting wire of a portion to be connected is divided into a plurality of dividing lines, and each dividing line is hardened with a hard brazing material. A sub-structure on one side and a sub-structure on the other side are butt-joined with a soft brazing material, and adjacent sub-structures are also joined with a soft brazing material.

According to a seventeenth aspect of the present invention, there is provided a superconducting wire connecting structure in which each superconducting wire of a portion to be connected is divided into a plurality of dividing lines, and a metal foil is wrapped around each dividing line to form a soft brazing material. The sub-structures are firmly fixed to each other, and the sub-structures on one side and the sub-structures on the other side are butt-joined with a soft brazing material, and adjacent sub-structures are also joined with a soft brazing material. It is a thing.

In the superconducting wire connection structure according to the eighteenth aspect of the present invention, each superconducting wire of a portion to be connected is thinned into a plurality of dividing lines, and each dividing line is inserted into and fixed to a metal tube. A fan-shaped sub-structure is formed, and the sub-structure on one side and the sub-structure on the other side are combined in a columnar shape and joined by a soft brazing material.

[0042]

According to the invention of claims 1 to 7, a cup having a high resistance layer or a high resistance modifying layer is provided on the strand of the superconducting wire to be connected, so that the cup flows between the strands in a varying magnetic field. Pulse resistance is reduced by increasing resistance to ring current and eddy current and reducing them.

In the inventions of claims 8 to 13, the portion of the superconducting wire to be connected is subdivided into dividing lines, and the high resistance metal interposer is arranged between the dividing lines.
The fluctuating magnetic fieldNote reduces the coupling current flowing between the dividing lines, thereby reducing the pulse loss.

In the fourteenth to eighteenth aspects of the present invention, the superconducting element wire group of the connection portion is divided into a plurality of substructures, and the substructures are joined to each other, so that the connection portion has a space. Size is small and handling is easy.

[0045]

Embodiments of the present invention will be described below with reference to the drawings. Example 1. FIG. 1 is a sectional view of a connecting portion showing a connecting structure of a superconducting wire according to an embodiment of the invention of claim 1, and its appearance is similar to that of FIG. Further, the same or corresponding parts as those in FIGS. 39 and 40 are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, 31 is a high resistance layer provided on the surface of each element wire 2 of the connection portion 3. This high resistance layer 3
1 is a material having an electric resistivity higher than that of the solder 4 which is a brazing material (about 7 × 10 ⁻⁹ Ωm) under extremely low temperature (operating temperature), for example, nickel alloy, chromium alloy or brass Etc.

In the superconducting magnet having the connection structure as described above, the current of the connecting portion 3 flows from the wire 2 on one side to the wire 2 on the other side through the high resistance layer 31. Therefore, the conductivity and thickness of the high resistance layer 31 are set so that the Joule heat generation (DC electric resistance loss) in the steady magnetic field becomes larger than the conventional value of 0.1 W within a range that does not hinder the operation of the superconducting magnet. If and are set, the resistance to the coupling current or eddy current between the wires 2 due to the fluctuating magnetic field is increased, so that the coupling loss (coupling current loss) and the eddy current loss are reduced, and thus the pulse loss is overall. Is reduced. As a result, the stability of the superconducting magnet can be maintained against changes in the magnetic field.

Example 2. Hereinafter, a more specific example of the high resistance layer 31 of Example 1 will be described. 2 is a sectional view of a connecting portion showing a connecting structure of a superconducting wire according to an embodiment of the invention of claim 2, FIG. 3 is an enlarged sectional view of a wire portion of FIG. 2, and the appearance of the connecting structure is as shown in FIG. It is the same. In FIG. 3, 6 is a superconducting wire, 7 is a stabilizing material provided on the outer periphery of the superconducting wire 6, 8 is provided between the superconducting wire 6 and the stabilizing material 7, and tin is used during the heat treatment for forming the wire 2. It is a barrier that prevents substances such as the above from diffusing to the stabilizing material 7.

In FIGS. 2 and 3, reference numeral 32 denotes a high resistance plating layer provided on the surface of the wire 2 of the connecting portion 3. The high resistance plating layer 32 has a higher electric resistivity than the solder 4. , Is formed by plating a metal such as a nickel alloy or a chromium alloy.

According to such a superconducting wire connection structure,
As described in the first embodiment, the coupling loss and the eddy current loss between the wires 2 due to the changing magnetic field are reduced. Further, since the high resistance plating layer 32 is provided as the high resistance layer, the formation thereof can be collectively processed in a large amount and the connecting portion 3 can be made compact.

Example 3. Next, FIG. 4 is a sectional view of a connecting portion showing a connecting structure of a superconducting wire according to an embodiment of the invention of claim 3, FIG. 5 is an enlarged sectional view of a wire portion of FIG. 4, and the appearance of the connecting structure is It is similar to FIG. In the figure, 33 is a high resistance film wound around the surface of the wire 2 of the connection part 3. This high resistance film 33 is a metal having a higher electrical resistivity than the solder 4, for example, nickel alloy, chromium alloy or brass. It is made of metal such as.

By winding the high resistance film 33 around the strands 2 of the connecting portion 3 as described above, the coupling loss and the eddy current loss between the strands 2 due to the fluctuating magnetic field are reduced as described in the first embodiment. Will be reduced. Further, the high resistance layer having a sufficient thickness can be formed.

Although the high resistance film 33 is wound around each of the strands 2 in the third embodiment, for example, as shown in FIG. Good. As a result, the pulse loss is slightly increased as compared with the case where the high resistance film 33 is wound one by one, but the labor for winding the high resistance film 33 is reduced.

Example 4. Next, FIG. 7 is a sectional view of a connecting portion showing a connecting structure of a superconducting wire according to an embodiment of the invention of claim 4, and FIG. 8 is an enlarged sectional view of a wire portion of FIG. It is similar to FIG. In the figure, 34 is a cylindrical high resistance sheath into which the strand 2 of the connection part 3 is inserted. This high resistance sheath 34 is made of a metal having a higher electric resistivity than the solder 4, for example, nickel alloy, chromium alloy. Or it is made of metal such as brass.

In this way, the high resistance sheath 34 is connected to the connecting portion 3
By covering the wires 2 of No. 2 with each other, the coupling loss and the eddy current loss between the wires 2 due to the changing magnetic field are reduced as described in the first embodiment. Further, the high resistance layer having a sufficient thickness can be easily formed.

In the fourth embodiment, the high resistance sheath 34 is placed on each of the strands 2 one by one. However, as shown in FIG. 9, for example, a plurality of strands 2 are formed into one high resistance sheath 34. You may insert all together. Further, in FIG. 8, the high resistance sheath 3
Although there is no gap between the outer circumference of the wire 4 and the outer circumference of the strand 2, the inner diameter of the high resistance sheath 34 may be made larger in order to simplify the insertion.

Example 5. Next, FIG. 10 is a sectional view of a connection portion showing a connection structure of a superconducting wire according to an embodiment of the invention of claim 5, and the appearance of the connection structure is similar to that of FIG. Further, FIG. 11 is an enlarged cross-sectional view showing a state before modification of the strand of FIG. 10, and FIG. 12 is an enlarged cross-sectional view of the strand after modification. In the figure, reference numeral 35 is a high resistance reforming layer obtained by reforming the stabilizing material 7 of the wire 2 so as to have an electric resistivity higher than that of the solder 4.

In this way, the stabilizing material 7 is applied to the high resistance modification layer 3
In the case of forming No. 5, the high resistance modifying layer 35 works similarly to the high resistance layer 31 of the first embodiment, and the coupling loss between the wires 2 and the eddy current loss due to the changing magnetic field are reduced. Further, as compared with the first to fourth embodiments, the cross section of the strand 2 does not increase, so that the connecting portion 3 can be made compact.

Example 6. Hereinafter, a more specific example of the high resistance modified layer 35 of Example 5 will be described. FIG.
FIG. 14 is a perspective view showing a wire after modification according to an embodiment of the invention of claim 6, and FIG. 14 is a sectional view of the wire of FIG. In the figure, 36 is a high resistance modifying layer formed on the stabilizing material 7 of the wire 2. This high resistance modifying layer 36 is a high resistance base material from the outer peripheral surface of the wire 2 to the stabilizing material 7. Is formed by diffusing nickel, chromium, tin or solder as
The electrical resistivity is higher than that of the solder 4. The above diffusion occurs by disposing a metal to be diffused around the strand 2 before reforming and heating it to a predetermined temperature.

In this way, the stabilizing material 7 is applied to the high resistance modification layer 3
By forming 6 as described in Example 5,
The coupling loss and the eddy current loss between the wires 2 due to the changing magnetic field are reduced. Further, by selecting the diffusion temperature and the diffusion time to desired values, the diffusion distance from the surface to the inside can be adjusted, and it is possible to freely select at which part the high resistance modification layer 36 is formed. The resistance value of the entire resistance modification layer 36 can be adjusted. Furthermore, in the case of a compound-based wire such as Nb ₃ Sn, the superconducting wire-forming heat treatment is usually carried out, so that the reforming work can be carried out at the same time, thereby shortening the working process or improving diversity. be able to.

Example 7. Next, FIG. 15 is a perspective view showing a wire after modification according to an embodiment of the invention of claim 7, and FIG. 16 is a sectional view of the wire of FIG. The wire of this Example 7 is
This is a type in which the stabilizing material 7 is arranged on the outer peripheral portion and the central portion. Therefore, the high-resistance modified layer 37 is formed from the end portion of the wire to the stabilizing material 7 with nickel as a high-resistance base material,
It is formed by diffusing chromium, tin, solder or the like.

In this way, the stabilizing material 7 is applied to the high resistance modification layer 3
By forming 7 as described in Example 5,
The coupling loss between the wires and the eddy current loss due to the changing magnetic field are reduced. Further, by diffusing the high resistance base material from the end of the wire, the high resistance modifying layer 37 can be formed also on the stabilizing material 7 arranged in the center of the wire.
It is possible to reduce the coupling current flowing between the superconducting wires in the strand of the book, and more reliably reduce the coupling loss due to the fluctuating magnetic field.

Although the stranded wire conductor is shown in Examples 1 to 7 above, a superconducting wire using a monolith wire may be used. Although the solder 4 is shown as the brazing material in the above-mentioned Examples 1 to 7, it may be indium or the like.

Example 8. Next, FIG. 17 is a front view showing a superconducting wire connection structure according to a first embodiment of the invention of claim 8.
FIG. 18 is a cross-sectional view of the connection portion of FIG. 17, and the same or corresponding parts as those in FIGS. 41 to 45 are designated by the same reference numerals and the description thereof will be omitted.

In the figure, two superconducting wires 11a, 11
The part (end) to be connected of b is subdivided into one twisted wire 12 which is a dividing line. These child twisted wires 12 are arranged so that their cross sections are arranged in a straight line, one row at a time, and the cross-sectional shape of the entire connecting portion 41 is rectangular.

Further, high resistance metal interposers 42 and 43 are arranged between the adjacent child twisted wires 12, and a brazing material is provided between the child twisted wires 12 and the high resistance metal interposers 42 and 43. (Soft brazing material)
Are filled with the solder 16. The high-resistivity intermetallic inserts 42 and 43 have an electrical resistivity (about 7 × 10 ⁻⁹⁾ of the solder 16.
Ωm), which is a metal having an electric resistivity higher than that of the solder 16, and which is well compatible with the solder 16, for example, a copper alloy. As such a copper alloy, for example, a copper-nickel alloy containing 10 to 30% nickel, or brass is easily available and suitable.

Next, the operation will be described. When the superconducting coil having the connecting portion 41 as described above is pulse-operated, the magnetic field generated changes according to the change in the energizing current, as in the conventional case. However, the connecting portion 4 of the eighth embodiment
1 is a high resistance metal intercalation product 42 between the adjacent twisted wires 12,
Since 43 is arranged, the coupling current flowing between the twisted pair wires 12 is reduced, and as a result, pulse loss is reduced.

Further, when Nb ₃ Sn is used as the superconducting wire, the twisted wire 1 as shown in FIG.
2 is molded, and Nb ₃ Sn forming heat treatment is performed after the molding. In the unheated state, the twisted strand 12 can be freely bent and stretched. After the heat treatment, the child twisted wire 12 of the superconducting wire 11a and the child twisted wire 12 of the superconducting wire 11b are overlapped, and the high resistance metal interposers 42 and 43 are arranged. After such assembly, the connection portion 41 is completed by pouring the solder 16 while heating.

As described above, by forming the twisted pair wires 12 before the heat treatment, no strain is applied to the Nb ₃ Sn superconducting wire during manufacturing, and the connecting portion 41 is integrated after manufacturing. And its rigidity is high. Therefore, even when a compound superconducting wire is used, deterioration of superconducting characteristics (superconducting critical current) is prevented and handling and management are easy.

Example 9. Next, FIG. 19 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to a second embodiment of the present invention. In the above-mentioned Example 8, the case where the superconducting wire 11 was subdivided into the twisted wires 12 was shown.
In the portion to be connected, the superconducting wire 11 is subdivided into individual strands 13, that is, one strand 13 is used as a dividing line. The other structure is almost the same as that of the eighth embodiment.

In such a connection structure, the coupling current between the strands 13 in the twisted pair wire 12, which was not reduced in the eighth embodiment, is also reduced, so that the pulse loss is further reduced. Further, if the superconducting wire 11 is subdivided and the strands 13 are molded before heat treatment, distortion is not applied to the superconducting wire, so that even if a compound superconducting wire is used, deterioration of the superconducting property (superconducting critical current) is prevented. It

Example 10. Next, FIG. 20 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to a third embodiment of the present invention. The connecting portion 41 of the tenth embodiment is such that a high resistance metal interposer 44 having a U-shaped cross section is arranged so as to surround the child twisted wire 12 which is a dividing line. The other structure is the same as that of the eighth embodiment (FIG. 18). The high resistance metal interposer 44 is manufactured by bending a plate material made of the same material as the other high resistance metal interposers 42 and 43.

In the connecting portion 41 configured as described above, the coupling current between the child twisted wires 12 is reduced by the high resistance metal intercalation products 42, 43 and 44, so that the eighth embodiment
The same effect as can be obtained. Also, a high resistance metal interposer 4
Since the high-resistance metal interposer 44 different from those 2 and 43 is provided, the resistance value can be optimally adjusted by selecting the thickness of the high-resistance metal interposer 44.

Example 11. FIG. 21 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to a fourth embodiment of the invention of claim 8;
Although the structure is simplified by omitting 3, since each child twisted wire 12 is surrounded by the high resistance metal interposer 44,
The same effect as that of the tenth embodiment can be obtained. Further, in order to join the plurality of high resistance metal interposers 44, for example, the high resistance metal interposers 44 processed by a single piece may be joined as shown in the figure using a hard brazing material or the like.

Example 12 22 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to a fifth embodiment of the present invention. The connection part 41 of this Example 12 is a high resistance metal interposer 45 in which a groove having a U-shaped cross section is machined, and is arranged so that the split strand 12, which is a split line, is located in the groove. is there. Further, the solder 16 is filled in the groove. The arrangement of the high-resistance metal interposers 42 and 43 is the same as that in the above-described Embodiment 8 (FIG. 18).

In the connecting portion 41 constructed as described above, since the coupling current between the child twisted wires 12 is reduced by the high resistance metal intercalation products 42, 43, 45, the embodiment 8 will be described.
The same effect as can be obtained. Also, a high resistance metal interposer 45
Since it is machined, its dimensional accuracy is good and dimensional adjustment work is not required when combining conductors. Therefore, the high-quality connection part 41 can be manufactured at low cost.

Example 13 FIG. 23 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to a sixth embodiment of the present invention.
3 is omitted, and the high resistance metal interposer 46 in which the high resistance metal interposer 45 of each superconducting wire 11a, 11b is integrated in advance is used. Such a high resistance metal interposer 46
Can be easily and accurately manufactured by cutting a groove for accommodating the individual twisted wires 12 one by one in a metal plate, and the manufacturing and assembly of the entire connecting portion 41 is easy.

Example 14. Next, FIG. 24 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to an embodiment of the present invention. In the figure, two superconducting wires 11a, 1
1b is subdivided into one child twisted wire 12 which is a dividing wire. These child twisted wires 12 are arranged so that their cross sections are arranged in a straight line with four rows in total of two rows,
The cross-sectional shape of the entire connecting portion 47 is rectangular.

Further, with respect to each of the superconducting wires 11a and 11b, the two twisted wires 12 lined up in the direction of the magnetic field (indicated by an arrow in the figure).
The connecting unit 48 is configured by, and the high resistance metal interposers 42 and 43 are arranged between the adjacent connecting units 48. Twisted wire 12 and high-resistance metal interposer 42,
The solder 16 is filled between the gaps 43 and 43.

In the connection structure as described above, when the connection unit 48 is projected in the direction of the magnetic field, the width in the direction perpendicular to the magnetic field is the same as that of the single twisted pair wire 12. The number of the child twisted wires 12 located in the portion surrounded by the objects 42 and 43 is larger than that of the first embodiment, but the pulse loss is suppressed to substantially the same level as that of the first embodiment. Also, the connecting portion 47
The manufacturing method of is similar to that of Example 1, except that the twisted wire 1
If all 2 (dividing lines) are the same, manufacturing is simpler and cheaper than in the first embodiment.

Example 15 In the fourteenth embodiment, an example in which the connecting unit 48 is configured by the twisted wires 12 arranged in the direction perpendicular to the connecting surface between the superconducting wires 11a and 11b has been shown. Depending on the direction, for example, as shown in FIG. 25, the superconducting wires 11a, 11
The connection unit 48 may be configured by the twisted pair wires 12 arranged in parallel to the connection surface between the b.

Example 16 In addition, in the above-mentioned Examples 14 and 15
Then, although the connecting unit 48 is composed of the two child twisted wires 12, it may be composed of a larger number depending on the magnetic field generated and the allowable pulse loss. For example, in the example shown in FIG. 26, the high resistance metal interposer 42 is completely removed, and only the high resistance metal interposer 43 between the superconducting wires 11a and 11b is arranged. Each of the child twisted wires 12 constitutes a connecting unit 48. In this case, because the configuration is very simple,
Manufacture and assembly are easy and inexpensive.

Example 17 Next, FIG. 27 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to an embodiment of the present invention. In the drawing, the two superconducting wires are subdivided into one twisted wire 12 which is a dividing line. These child twisted wires 12 are arranged so that their cross sections are arranged in a circle, and the child twisted wires 1 of one superconducting wire are arranged.
2 and the other twisted wire 12 of the superconducting wire (in the figure, 12a, 12a
It was distinguished as b. ) And are arranged alternately on the same circumference. The entire connecting portion 51 has a cylindrical shape.

A high resistance metal interposer 52 is arranged between the adjacent child twisted wires 12, and solder 16 is filled between the child twisted wire 12 and the high resistance metal interposer 52. There is. The high resistance metal interposer 52 is made of the same high resistance metal as in the above-described respective embodiments.

In such a connection structure, since the superconducting wire is subdivided into units of the child twisted wires 12 and the high resistance metal interposer 52 is arranged between the adjacent child twisted wires 12, the connection is made. When the superconducting coil having the portion 51 is pulse-operated, the coupling current flowing between the child twisted wires 12 is reduced and the pulse loss is reduced. Further, by making the connecting portion 51 cylindrical, the connection resistance between the child twisted wires 12 becomes uniform, and the current distribution to each child twisted wire 12 becomes even. Further, since the inner surface of the cylindrical shape is also cooled by the refrigerant, it has a high cooling capacity and becomes more thermally stable.

Further, in order to manufacture the above-mentioned connecting portion 51,
It is sufficient to insert a spacer into the nested portion of the mating conductor and perform molding, for example, heat treatment for Nb ₃ Sn generation, because strain is not applied to the superconducting wire, deterioration of superconducting properties is prevented, and handling management is easy. become.

Example 18. Next, FIG. 28 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to an embodiment of the present invention. In the above-mentioned Example 17, the child twisted wires 12a and the child twisted wires 12b are alternately arranged on the same circumference, but in this Example 18, the child twisted wires 1 are radially outside the child twisted wires 12a.
2b is arranged. The overall shape of the connecting portion 53 is cylindrical, and the portion of one superconducting wire to be connected fits into the other.

Further, a high resistance metal interposer 54 is arranged between the child twisted wires 12 adjacent in the circumferential direction, and a high resistance metal interposer 55 is arranged between the child twisted wires 12 adjacent in the radial direction. It is arranged. Further, the twisted pair wire 12 and the high resistance metal interposer 54,
The solder 16 is filled in the space between 55 and 55. The high resistance metal interposers 54 and 55 are made of the same high resistance metal as in the above embodiments.

In the connection structure of the eighteenth embodiment, although the arrangement of the child twisted wires 12 is different from that of the seventeenth embodiment, since the high resistance metal interposers 54 and 55 are arranged between the child twisted wires 12,
A similar pulse loss reduction effect can be obtained. In addition, since the cylindrical shape is formed of the single conductor at the time of forming the connecting portion, the manufacturing is easier and cheaper, and the reliability is improved. In addition, no strain is applied to the superconducting wire at the time of manufacture, deterioration of the superconducting properties is prevented, and handling and management becomes easy.

Example 19 Next, FIG. 29 is a cross-sectional view of a connecting portion showing a superconducting wire connecting structure according to an embodiment of the invention of claim 12. In the figure, the two superconducting wires are subdivided into one twisted wire 12 which is a dividing line. In addition, as in Example 17, the twisted pair wires 12a and 12b
Have their cross sections alternately arranged on the same circumference. However, the connecting portion 5 of Example 19 differs from Examples 17 and 18 in that the overall shape is cylindrical.

Further, between the adjacent twisted wires 12, a high resistance metal interposer 57 radially arranged from the center of the cross section of the connecting portion 56 is arranged. The solder 16 is filled between the metal insert 57. The high resistance metal interposer 57 is made of the same high resistance metal as in the above-mentioned respective embodiments.

According to such a connecting portion 56, the superconducting wire is subdivided into units of the child twisted wires 12, and the high resistance metal interposer 57 is arranged between the adjacent child twisted wires 12. The pulse loss is reduced as in the above embodiments. In addition, since the child twisted wire 12 is arranged in a circular cross section, the child twisted wire 12
The connection resistance between them becomes even, and the current distribution to each twisted pair wire 12 becomes even. Furthermore, in the nineteenth embodiment, since the connecting portion 56 is formed in the cylindrical shape, the entire connecting portion 56 can be made compact.

Further, in order to manufacture the above-mentioned connecting portion 56,
As in Example 17, it is sufficient to insert spacers in the nested portions of the mating conductor and perform molding, for example, heat treatment for Nb ₃ Sn generation, to prevent distortion in the superconducting wire and prevent deterioration in superconducting properties. In addition, handling management becomes easy.

Example 20. Next, FIG. 30 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to an embodiment of the present invention. In this Example 20, in Example 18 described above.
Similarly, the child twisted wire 12b is arranged outside the child twisted wire 12a in the radial direction. The overall shape of the connecting portion 58 is cylindrical, and the portion of one superconducting wire to be connected fits into the other.

A high resistance metal interposer 59 is arranged between the adjacent twisted wires 12b, and a high resistance metal interposer 60 is arranged between the adjacent child twisted wires 12 in the radial direction. There is.
Further, between the adjacent twisted wires 12a, the high resistance metal interposer 6 radially arranged from the center of the cross section of the connecting portion 58.
1 is arranged, the twisted pair wire 12 and the high resistance metal interposer 5
The solder 16 is filled between 9, 60 and 61. The high resistance metal interposers 59, 60 and 61 are made of the same high resistance metal as in the above embodiments.

In the connection structure of this Embodiment 20, since the high resistance metal interposers 59, 60 and 61 are arranged between the child twisted wires 12, the pulse loss is reduced. In addition, since the single conductor has a cylindrical shape or a cylindrical shape at the time of forming the connecting portion, the manufacturing is easier, the cost is lower, and the reliability is improved. Further, no strain is applied to the superconducting wire at the time of manufacture, deterioration of the superconducting characteristics is prevented, and handling and management are facilitated.

Although the split lines are the twisted strands 12 in the above Examples 10 to 20, the split lines may be the strands 13 as shown in Example 9. Further, the twisted wire structure of the superconducting wire to be connected is not limited to that shown in FIG. 43, and may be, for example, one having a twisted wire structure of a tertiary or higher order or a flat wire.

Example 21. Next, FIG. 31 is a constitutional view showing a connection structure of a forced cooling type superconducting wire according to an embodiment of the invention of claim 14, and the same or corresponding parts as in FIG. 46 and FIG. The description is omitted. In the figure, 71 is a low resistance metal tube (for example, copper tube), 72 is a dividing line (element wire bundle) formed by subdividing the secondary twisted wires 23 of the parts to be connected to each other, and 73 is a dividing line 72. It is a sub-structure that is inserted into the metal tube 71, fixed with solder (soft brazing material) 29, and then compression-molded into a rectangular shape.

Further, the tips of the substructures 73 of the respective superconducting wires are butt-joined to each other by the solder 29, and the adjacent substructures 73 are also joined by the solder 29. Further, the butting positions of the sub-structures 73 are staggered as shown in the figure. The cooling channels 26a and 26b and the connecting portion cover 30 are omitted for simplicity.

Next, the operation will be described. With the connection structure shown in FIG. 31, connection can be made without overlapping the connection parts as shown in FIG. 47, and the connection parts become spatially compact. Further, since the secondary twisted wire 23 is subdivided into a plurality of split wires 72 and the split wires 72 are the sub-structures 73, the rigidity of the connection portion is increased and the handling is facilitated, and therefore the twisting workability is improved. It becomes possible to connect a linear forced cooling type superconducting wire.

Furthermore, by shifting the abutting positions of the sub-structures 73 in a stepwise manner, the strength of the connecting portion is increased, and the superconducting stability and reliability are improved.

As a method of manufacturing the sub-structure 73, the dividing line 72 may be inserted into the metal tube 71 and pressure-molded, and then the dividing line 72 and the metal tube 71 may be soldered.

Example 22. Next, FIG. 32 is a cross-sectional view of a sub-structure according to an embodiment of the invention of claim 15, and in the figure, 74 is a fused portion. In the twenty-first embodiment, the secondary twisted wire 23 is divided into a plurality of split wires 72, which are inserted into the metal tube 71 and soldered and then compression-molded into a rectangular shape. However, in the twenty-second embodiment, instead of soldering, Utilizes fusion.

For example, Nb ₃ Sn, a high temperature (about 70
In a superconducting wire in which a heat treatment for producing a superconducting substance is carried out at 0 ° C. for a long time (tens of hours), as shown in FIG. Since the stabilized copper 21a and the metal tube 71 are fused together, soldering inside the metal tube 71 is not necessary.

By fusing the strands 21 in the metal tube 71 in this way, reliability can be improved and a connection portion having a low resistance can be obtained as compared with the case of soldering.

Example 23. Next, FIG. 33 is a perspective view showing a superconducting wire connection structure according to an embodiment of the present invention. In the above-mentioned Examples 21 and 22, the dividing line 72 was inserted into the metal tube 71 to manufacture the sub-structure 73, but in this Example, the dividing line 72 is made of hard brazing material, that is, hard solder (high temperature solder) 75. After being solidified by hardening, it is formed into a corner structure to form a sub-structure 73. The substructures 73 are joined to each other by
The solder (soft solder) 29 is used.

As described above, by using the hard solder 75 instead of the metal tube 71, the connecting portion becomes more compact.

Example 24. 34A and 34B are diagrams showing another example of a method for abutting the sub-structures 73, where FIG. 34A is a plan view, FIG. 34B is a side view, and FIG. 34C is a bottom view. Example 2
1 to 23, the upper and lower two-layer sub-structure 73 viewed from the side surface
However, in the twenty-fourth embodiment, the butting positions of the upper and lower substructures 73 are shifted in a stepwise manner in the opposite direction.

With such a connecting structure, the strength of the connecting portion is further increased, and the superconducting stability and reliability are further improved.

Example 25. FIG. 35 is a plan view showing still another example of the butting method of the sub-structures 73. In Example 25, the length of the substructure 73 of one superconducting wire is made longer in the central portion in the width direction and shorter at both ends, and the substructure 73 of the other superconducting wire is shorter in the central portion and at both end portions. The position of the joint is shifted so that it becomes longer.

As described above, by arranging the two superconducting wire substructures 73 so that one is in a convex shape and the other is in a concave shape, the length of the connecting portion can be made smaller than that in Examples 21 to 24. Can be shortened.

Example 26. Here, the above-mentioned Examples 21 to 2
In No. 5, since the substructure 73 is configured by using the metal tube 71 of low resistance such as copper or the hard solder 75, the connection resistance value of the connection portion is low, which is desirable as a method of connecting the superconducting coil for direct current operation. Is the way. However, in the case of a superconducting coil that performs pulse operation, there is a drawback that the pulse loss (AC loss) is large as described above. In a superconducting coil that performs pulse operation, the maximum current does not flow continuously. Therefore, in order to reduce pulse loss, the wires 21 that are separated from each other even if the connection resistance value of the connection part is high.
It is desirable that the electrical coupling (coupling) between them is small.

FIG. 36 is a constitutional view showing a connection structure of a forced cooling type superconducting wire according to another embodiment of the invention of claim 14. In this twenty-sixth embodiment, as the metal tube forming the sub-structure 73, the electrical resistivity of the solder 29 (about 7 × 10 ⁻⁹ Ω) is used.
made of a high resistance metal having an electric resistivity higher than that of m),
For example, a CuNi (cupronickel) tube 76 is used.

As described above, by using the CuNi tube 76 having a high resistance, the electric coupling force between the wires 21 located at positions distant from each other is weakened, and the pulse loss in the superconducting coil for pulse operation is reduced. Get smaller.

Example 27. Next, FIG. 37 is a configuration diagram showing a connection structure of a forced cooling type superconducting wire according to an embodiment of the invention of claim 17. In the above embodiment, the low resistance metal tube 71 is used.
Alternatively, a high resistance CuNi tube 76 may be used to form the substructure 73.
In the substructure 73 of the twenty-seventh embodiment, a metal foil 77 made of a metal having a low resistance (for example, copper) or a high resistance (for example, CuNi) is wound around the dividing line 72, and the solder 2 is used.
After being fixed at 9, it is compression molded into a rectangular shape.

As described above, when the sub-structure 73 is formed by using the metal foil 77, the connecting portion is more compact than when the metal tube 71 or the CuNi tube 76 is used, and the hard solder 75 is used. It is easier to handle than the case.

Although the substructure 73 is compression-molded into a rectangular shape because the rectangular forced cooling type superconducting wire is used in the above embodiment, the cross-sectional shape of the substructure 73 is appropriately selected so that the entire connecting portion is compact. do it.

Example 28. For example, FIG.
3 is a perspective view showing a bundle type superconducting wire according to an embodiment of the invention of FIG. In this way, in the case of the bundle type superconducting wire,
The sub-structure 73 may be formed by molding the metal pipe 71 into which the dividing line 72 is inserted into a fan-shaped cross section. In this case, the other bundle conductor is also processed in the same manner, and the sub-structure 7
It suffices to combine the three into a columnar shape and fix them by soldering, and the connecting portion becomes compact.

Further, the sub-structure 73 of the 28th embodiment is used.
May be butt-joined with different lengths. Further, instead of the metal tube 71, a CuNi tube 76 or a metal foil 77.
Etc. may be used.

Further, in the above-mentioned Examples 21 to 28, the forced cooling type superconducting wire in which the periphery of the secondary twisted wire 23 is covered with the conduit 25 is shown, but a normal superconducting wire not using the conduit 25 may be used.

[0121]

As described above, in the superconducting wire connection structure according to the first aspect of the present invention, the high resistance layer made of a material having a higher electrical resistivity than the brazing material is provided on the outer circumference of the wire to be connected. By adjusting the conductivity and thickness of this high resistance layer, Joule heat generation in a steady magnetic field is maintained at a level that does not hinder the operation of the device, and The pulse loss can be reduced, and the reliability can be improved.

In the superconducting wire connection structure of the second aspect of the present invention, since the outer periphery of the wire to be connected is plated with a high resistance plating layer made of a metal having a higher electrical resistivity than the brazing material, In addition to the same effect as the invention of claim 1, the formation of the high resistance layer can be carried out in a large amount at one time, the productivity can be improved, and the connection portion can be made compact. Produce an effect.

Further, in the superconducting wire connection structure according to the third aspect of the present invention, the high resistance film made of a metal having a higher electric resistivity than the brazing material is wound around the outer circumference of the wire to be connected. In addition to the same effect as the invention of claim 1,
This has the effect of forming a sufficiently thick high-resistance layer.

Furthermore, in the superconducting wire connection structure of the invention of claim 4, the outer periphery of the wire to be connected is covered with a high resistance sheath made of a metal having a higher electrical resistivity than the brazing material. In addition to the same effect as the invention of claim 1,
This has the effect that a sufficiently thick high resistance layer can be easily formed.

The superconducting wire connection structure according to the fifth aspect of the present invention has a high resistance obtained by modifying the material for stabilizing the wire in the portion to be connected so as to have a higher electric resistivity than the brazing material. Since the modified layer is formed, in addition to the same effect as that of the invention of claim 1, there is an effect that the increase in the cross-sectional diameter of the wire can be suppressed and the connecting portion can be made compact.

Further, in the superconducting wire connection structure according to the invention of claim 6, the stabilizing material for the wire to be connected is made to have a higher electrical conductivity than the brazing material by diffusing the metal material from the outer peripheral surface of the wire. Since the high-resistance modified layer modified to have a high resistivity is formed, the diffusion distance is adjusted by selecting the diffusion temperature and the diffusion time, in addition to the same effect as that of the invention of claim 1. In addition, since the diffusion position can be freely selected, the resistance value of the high resistance modified layer can be adjusted. Further, when a compound-based superconducting wire is used, it is possible to carry out a reforming work during the heat treatment for forming the superconducting wire, and it is possible to shorten the working process and improve the variety.

Furthermore, in the superconducting wire connection structure according to the invention of claim 7, the stabilizing material for the wires to be connected is made to have a metal material diffused from the ends of the wires, so that it is better than the brazing material. Since the high-resistance modified layer modified so as to have a high electric resistivity is formed, in addition to the effect similar to that of the invention of claim 6, a stabilizer is arranged in the central portion of the cross section of the wire. In the case where the element is present, this can be easily modified, and the coupling loss in each wire can be reduced, and the pulse loss can be reduced more reliably.

Further, in the superconducting wire connection structure of the present invention, the superconducting wire of the portion to be connected is subdivided into a plurality of dividing lines, and the electric resistance between the adjacent dividing lines is higher than that of the brazing material. Since a high resistance metal interposer made of a metal with a high resistance is arranged, it is possible to reduce the coupling current that flows between the adjacent dividing lines during pulse operation, which can reduce pulse loss, which results in operation This has the effect of preventing normal conduction transition and improving reliability. Further, since the connecting portion is integrated and the rigidity is high, it is difficult to apply strain to the superconducting wire, and therefore even when a compound superconducting wire is used, it is possible to prevent deterioration of superconducting properties due to strain. Also effective.

Further, in the superconducting wire connection structure according to the invention of claim 9, a connecting unit is constituted by a plurality of dividing lines arranged in the direction of the magnetic field, and a high resistance metal interposer is provided between the connecting units. Are arranged, the same effect as the invention of claim 1 can be obtained with a simple structure, and the production of the connecting portion can be simplified and the cost can be reduced.

Furthermore, in the superconducting wire connection structure of the invention of claim 10, the dividing lines are arranged in a circular cross section, and the dividing lines of each superconducting wire are alternately arranged. In addition to the same effect, the connection resistance between the dividing lines becomes even and the current distribution can be made even.
Further, since the entire connecting portion is formed in a cylindrical shape, the connecting portion can be cooled from the inside of the cylinder, and as a result, the cooling capacity can be increased and the thermal stability can be further improved.

According to the eleventh aspect of the present invention, in the superconducting wire connection structure, the dividing lines are arranged in a circular cross section, and the dividing lines on the other side are arranged radially outside the dividing lines on one side. In addition to the same effect as the invention of claim 8 described above, a cylindrical shape can be formed by a single conductor at the time of forming the connecting portion, which makes the manufacturing easy and inexpensive and improves the reliability. In addition, since the entire connecting portion has a cylindrical shape, the connecting portion can be cooled from the inside of the cylinder, and as a result, the cooling capacity can be increased and the thermal stability can be further improved.

Further, in the superconducting wire connection structure of the invention of claim 12, the dividing lines are arranged in a circular cross section, and the dividing lines of each superconducting wire are arranged alternately.
In addition to the effect similar to that of the invention described above, the connection resistance between the division lines becomes uniform, the current distribution can be made uniform, and the connection part is made columnar, thereby making the connection part compact. There is an effect such as being able to.

Furthermore, in the superconducting wire connection structure of the thirteenth aspect of the present invention, the dividing lines are arranged in a circular cross section, and the dividing lines on the other side are arranged radially outside of the dividing lines on one side. Therefore, in addition to the same effect as that of the invention of claim 8, a cylindrical shape and a cylindrical shape can be constituted by a single conductor at the time of forming the connecting portion, which makes the manufacturing easy and inexpensive and improves the reliability. Further, since the entire connecting portion has a cylindrical shape, the connecting portion can be made compact.

According to a fourteenth aspect of the present invention, there is provided a superconducting wire connection structure, wherein each superconducting wire of a portion to be connected is thinned into a plurality of dividing lines, and each dividing line is inserted into a metal tube. Since the sub-structures are configured and the opposing sub-structures are butt-joined to each other, the connection part can be made spatially compact, and the connection part can be easily handled to improve workability. Can
In addition, the rigidity of the connecting portion can be increased to prevent the deterioration of the superconducting characteristics of the connecting portion due to the distortion.

Furthermore, in the superconducting wire connection structure of the fifteenth aspect of the present invention, the sub-structure is constructed by heat-bonding the strands of the dividing wire inserted in the metal pipe and between the strands and the metal pipe by heating. Therefore, in addition to the same effect as the invention of claim 14, the reliability of the connection can be improved, and a connection portion having a lower resistance can be obtained.

Furthermore, in the superconducting wire connection structure of the sixteenth aspect of the present invention, since the dividing line is hardened by the hard brazing material to form the sub-structure, the same effect as that of the above-described fourteenth aspect of the invention is obtained. In addition to this, there is an effect that the connecting portion can be made more compact.

In the superconducting wire connection structure according to the seventeenth aspect of the present invention, since a metal foil is wound around the dividing line and fixed with a soft brazing material to form a sub-structure, the same effect as that of the above-described fourteenth aspect of the invention is provided. In addition, the connection portion can be made more compact than the case of using the metal pipe, and the handling can be made easier than the case of using the hard brazing filler metal.

Further, in the superconducting wire connection structure of the eighteenth aspect of the present invention, the sub-structures are fan-shaped in cross section, and the opposing sub-structures are combined and joined in a cylindrical shape. The same effect as the invention is achieved.

[Brief description of drawings]

FIG. 1 is a sectional view of a connection portion showing a connection structure of a superconducting wire according to an embodiment of the invention of claim 1.

FIG. 2 is a cross-sectional view of a connection portion showing a superconducting wire connection structure according to an embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of a wire portion of FIG.

FIG. 4 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to an embodiment of the invention of claim 3;

5 is an enlarged cross-sectional view of a wire portion of FIG.

FIG. 6 is a cross-sectional view of an essential part showing another embodiment of the invention of claim 3;

FIG. 7 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to an embodiment of the invention of claim 4;

8 is an enlarged cross-sectional view of the wire portion of FIG.

FIG. 9 is a cross-sectional view of an essential part showing another embodiment of the invention of claim 4;

FIG. 10 is a cross-sectional view of a connection portion showing a superconducting wire connection structure according to an embodiment of the invention of claim 5;

11 is an enlarged cross-sectional view showing a state before modification of the strand of FIG.

FIG. 12 is an enlarged cross-sectional view of a wire after modification.

FIG. 13 is a perspective view showing a wire after reforming according to an embodiment of the invention of claim 6;

14 is a cross-sectional view of the strand of FIG.

FIG. 15 is a perspective view showing a wire after reforming according to an embodiment of the invention of claim 7;

16 is a cross-sectional view of the strand of FIG.

FIG. 17 is a front view showing a superconducting wire connection structure according to a first embodiment of the present invention.

18 is a cross-sectional view of the connection portion of FIG.

FIG. 19 is a sectional view of a connection portion showing a superconducting wire connection structure according to a second embodiment of the invention of claim 8;

FIG. 20 is a sectional view of a connection portion showing a superconducting wire connection structure according to a third embodiment of the invention of claim 8;

FIG. 21 is a sectional view of a connection portion showing a superconducting wire connection structure according to a fourth embodiment of the invention of claim 8;

FIG. 22 is a sectional view of a connecting portion showing a connecting structure of a superconducting wire according to a fifth embodiment of the invention of claim 8;

FIG. 23 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to a sixth embodiment of the invention of claim 8;

FIG. 24 is a sectional view of a connection portion showing a superconducting wire connection structure according to an embodiment of the invention of claim 9;

FIG. 25 is a sectional view of a connection portion showing a superconducting wire connection structure according to another embodiment of the invention of claim 9;

FIG. 26 is a sectional view of a connection portion showing a superconducting wire connection structure according to still another embodiment of the ninth invention.

FIG. 27 is a cross-sectional view of a connection portion showing a superconducting wire connection structure according to an embodiment of the invention of claim 10;

FIG. 28 is a sectional view of a connecting portion showing a superconducting wire connection structure according to an embodiment of the invention of claim 11;

FIG. 29 is a sectional view of a connecting portion showing a superconducting wire connecting structure according to an embodiment of the invention of claim 12;

FIG. 30 is a sectional view of a connection portion showing a superconducting wire connection structure according to an embodiment of the invention of claim 13;

FIG. 31 is a configuration diagram showing a connection structure of a forced cooling type superconducting wire according to an embodiment of the invention of claim 14;

FIG. 32 is a sectional view of a sub-structure according to an embodiment of the invention of claim 15;

FIG. 33 is a configuration diagram showing a connection structure of a forced cooling type superconducting wire according to an embodiment of the invention of claim 16;

FIG. 34 is a diagram showing another example of the butting method for the sub-structures of FIGS. 31 to 33.

FIG. 35 is a plan view showing still another example of the butting method for the sub-structures of FIGS. 31 to 33.

FIG. 36 is a configuration diagram showing a connection structure of a forced cooling type superconducting wire according to another embodiment of the invention of claim 14;

FIG. 37 is a configuration diagram showing a connection structure of a forced cooling type superconducting wire according to an embodiment of the invention of claim 17;

FIG. 38 is a perspective view showing a substructure of a bundle-type superconducting wire according to an embodiment of the invention of claim 18;

FIG. 39 is a perspective view showing an example of a conventional superconducting wire connection structure.

40 is a cross-sectional view of the connection portion of FIG. 39.

FIG. 41 is a front view showing another example of a conventional superconducting wire connection structure.

42 is an enlarged perspective view showing a main part of FIG. 41. FIG.

43 is a cross-sectional view illustrating the configuration of the superconducting wire of FIG. 41.

FIG. 44 is a relationship diagram showing an example of the relationship between the applied strain and the critical current in the Nb ₃ Sn superconducting conductor.

FIG. 45 is a schematic perspective view showing an example of a pancake coil having a connection structure as shown in FIG. 41.

FIG. 46 is a sectional view of an example of a conventional forced cooling type superconducting wire.

47 is a configuration diagram showing a connection structure of the superconducting wire of FIG. 46.

[Explanation of symbols]

 1 Superconducting Wire 2 Elemental Wire 4 Solder (Brazing Material) 7 Stabilizing Material 11 Superconducting Wire 12 Twisted Wire (Dividing Wire) 13 Elementary Wire (Dividing Wire) 29 Solder (Soft Brazing Material) 31 High Resistance Layer 32 High Resistance Plating Layer 33 high resistance film 34 high resistance sheath 35 high resistance modified layer 36 high resistance modified layer 37 high resistance modified layer 41 connection 42 high resistance metal intercalation 43 high resistance metal intercalation 44 high resistance metal intercalation 45 High resistance metal interposer 46 High resistance metal interposer 47 Connection part 48 Connection unit 51 Connection part 52 High resistance metal interposer 53 Connection part 54 High resistance metal interposer 55 High resistance metal interposer 56 Connection Part 57 High resistance metal interposer 58 Connection part 59 High resistance metal interposer 60 High resistance metal interposer 61 High resistance metal interposer 71 Metal tube 72 Dividing line 73 Sub structure 74 Fusion part 75 Hard solder ( (Hard brazing material) 6 CuNi tube (metal tube) 77 metal foil

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsuyoshi Toyota 1-2-2 Wadazaki-cho, Hyogo-ku, Kobe Sanritsu Electric Co., Ltd. Kobe Works (72) Inventor Naoyuki Harada 1 Wadazaki-cho, Hyogo-ku, Kobe Chome 1-2 Sanrishi Electric Co., Ltd. Kobe Works

Claims (18)

[Claims] 1. A superconducting wire connection structure in which parts of the superconducting wire to be connected are connected to each other through a brazing material.
A superconducting wire connection structure, wherein a high resistance layer made of a material having a higher electrical resistivity than the brazing material is provided on the outer periphery of the strand of wire to be connected. 2. A connection structure of superconducting wires, wherein parts to be connected of the superconducting wires are connected via a brazing material.
A superconducting wire connection structure, wherein a high resistance plating layer made of a metal having a higher electrical resistivity than the brazing material is plated on the outer periphery of the strand of wire to be connected. 3. A connection structure of superconducting wires, wherein parts to be connected of the superconducting wires are connected via a brazing material.
A superconducting wire connection structure, wherein a high resistance film made of a metal having a higher electric resistivity than the brazing material is wound around the outer circumference of the wire to be connected. 4. A connection structure of superconducting wires, wherein parts to be connected of the superconducting wires are connected via a brazing material.
A superconducting wire connection structure, characterized in that a high resistance sheath made of a metal having a higher electrical resistivity than the brazing material is covered on the outer circumference of the strand of wire to be connected. 5. A connection structure of superconducting wires, wherein parts to be connected of the superconducting wires are connected via a brazing material.
Connection of a superconducting wire, characterized in that a high-resistance modified layer modified to have a higher electric resistivity than the brazing material is formed on the material for stabilizing the strands of wire to be connected. Construction. 6. A connection structure of superconducting wires, wherein parts to be connected of the superconducting wires are connected via a brazing material.
A high resistance reformer that is modified to have a higher electrical resistivity than the brazing material by diffusing a metal material from the outer peripheral surface of the strand into the stabilizer of the strand to be connected. A superconducting wire connection structure characterized in that layers are formed. 7. A superconducting wire connection structure, wherein parts to be connected of the superconducting wire are connected to each other through a brazing material.
A high-resistance reformer modified to have a higher electrical resistivity than the brazing material by diffusing a metal material from the end of the strand into the stabilizer of the strand to be connected. A superconducting wire connection structure characterized in that layers are formed. 8. A superconducting wire connection structure in which parts to be connected of a superconducting wire in which a plurality of strands are twisted are connected to each other through a brazing material. , Each of which is subdivided into a plurality of dividing lines arranged linearly in cross section, and has a rectangular cross-sectional shape of the entire connecting portion. A superconducting wire connection structure in which a high resistance metal interposer made of a metal having a high electric resistivity is arranged. 9. In a superconducting wire connection structure in which parts to be connected of a superconducting wire in which a plurality of strands are twisted are connected to each other via a brazing material, each superconducting wire in the part to be connected is , Each of which is subdivided into a plurality of dividing lines arranged linearly in cross section, and the sectional shape of the entire connecting portion is rectangular, and by the plurality of dividing lines arranged in the direction of the magnetic field. A superconducting wire connection characterized in that a connection unit is configured, and a high resistance metal interposer made of a metal having a higher electric resistivity than the brazing filler metal is arranged between adjacent connection units. Construction. 10. A superconducting wire connection structure in which parts to be connected of a superconducting wire in which a plurality of strands are twisted are connected to each other through a brazing material, wherein each superconducting wire in the part to be connected is , Each of which is divided into a plurality of dividing lines arranged in a circular cross section, and the dividing lines of each of the above-mentioned superconducting wires are alternately arranged so that the entire connecting portion is cylindrical and adjacent to each other. A superconducting wire connection structure, in which a high resistance metal interposer made of a metal having a higher electrical resistivity than the brazing material is arranged between the dividing lines. 11. A superconducting wire connection structure in which parts to be connected of a superconducting wire in which a plurality of strands are twisted are connected to each other through a brazing material, wherein each superconducting wire in the part to be connected is , Each of which is subdivided into a plurality of dividing lines arranged in a circular cross section, and the dividing line of the portion to be connected to the other is located radially outside the dividing line of the portion to be connected to the other. , The entire connecting portion is cylindrical, and a high resistance metal interposer made of a metal having a higher electric resistivity than the brazing material is arranged between the adjacent dividing lines. Superconducting wire connection structure. 12. A superconducting wire connection structure in which parts to be connected of a superconducting wire in which a plurality of strands are twisted are connected to each other through a brazing material, wherein each superconducting wire in the part to be connected is , Each of which is divided into a plurality of dividing lines arranged in a circular cross section, and the dividing lines of each of the above-mentioned superconducting wires are alternately arranged, so that the entire connecting portion has a cylindrical shape and is adjacent to each other. A superconducting wire connection structure, in which a high resistance metal interposer made of a metal having a higher electrical resistivity than the brazing material is arranged between the dividing lines. 13. A superconducting wire connection structure in which parts to be connected of a superconducting wire in which a plurality of strands are twisted are connected to each other through a brazing material, wherein each superconducting wire in the part to be connected is , Each of which is subdivided into a plurality of dividing lines arranged in a circular cross section, and the dividing line of the portion to be connected to the other is located radially outside the dividing line of the portion to be connected to the other. , The entire connecting portion is in the shape of a cylinder, and a high resistance metal interposer made of a metal having a higher electric resistivity than the brazing material is arranged between the adjacent dividing lines. Superconducting wire connection structure. 14. A superconducting wire connection structure in which portions to be connected of a superconducting wire in which a plurality of strands are twisted are connected to each other using a soft brazing material. Are divided into a plurality of dividing lines, and each of the dividing lines is inserted into a metal tube and fixed with the soft brazing material to form a sub-structure. A superconducting wire connection structure characterized in that the structure and the sub-structure on the other side are butt-joined by the soft brazing material, and adjacent sub-structures are joined by the soft brazing material. . 15. A superconducting wire connection structure in which parts to be connected of a superconducting wire in which a plurality of strands are twisted are connected to each other using a soft brazing material. Are each thinned into a plurality of dividing lines, and each of the dividing lines is inserted into a metal tube and heat-fused to form a sub-structure, and a sub-structure on one side and A superconducting wire connection structure characterized in that the sub-structure on the other side is butt-joined by the soft brazing material, and adjacent sub-structures are joined by the soft brazing material. 16. A superconducting wire connection structure in which portions to be connected of a superconducting wire in which a plurality of strands are twisted are connected to each other using a soft brazing material, and each superconducting wire in the portion to be connected is a superconducting wire. Are divided into a plurality of dividing lines, and each of the dividing lines is hardened by a brazing filler metal to form a sub-structure. Further, the sub-structure on one side and the side on the other side are formed. The sub-structure of claim 1 is butt-joined by the soft brazing material, and the sub-structures adjacent to each other are joined by the soft brazing material. 17. A superconducting wire connection structure in which portions to be connected of a superconducting wire in which a plurality of strands are twisted are connected using a soft brazing material, and each superconducting wire in the portion to be connected is a superconducting wire. Are each divided into a plurality of dividing lines, and each of the dividing lines is wrapped with a metal foil and fixed with the soft brazing material to form a sub-structure, and the sub-structure on one side is further formed. While the body and the sub-structure on the other side are butt-joined by the soft brazing material,
A superconducting wire connection structure, characterized in that adjacent sub-structures are joined together by the soft brazing material. 18. In a superconducting wire connection structure, wherein the parts to be connected of a superconducting wire in which a plurality of strands are twisted are connected to each other using a soft brazing material, each superconducting wire in the part to be connected. Are divided into a plurality of dividing lines, and each dividing line is inserted and fixed in a metal tube to form a sub-structure having a sectoral cross section. A superconducting wire connection structure, characterized in that the substructure on the other side is combined in a cylindrical shape and is joined by the soft brazing material.