JP6738720B2 - Superconducting wire connection structure - Google Patents

Description

The present invention relates to a superconducting wire connection structure.

In recent years, RE-based superconducting wire has attracted attention as an oxide superconducting wire whose critical temperature (Tc) is higher than liquid nitrogen temperature (about 77K). A typical example is an RE-based superconductor (RE: rare earth element), for example, an yttrium-based superconductor represented by the chemical formula YBa ₂ Cu ₃ O _7-y (hereinafter, Y-based superconductor). When applying a RE superconducting wire to applications such as MRI and NMR that require a stable magnetic field over time, operation in the persistent current mode, which minimizes magnetic field attenuation, is an effective option. Must be connected between the superconducting coils or between the superconducting coil and the persistent current switch with a connection resistance of 10 ^-11 Ω or less.
The RE superconducting wire has a structure in which an oxide superconducting film made of ceramics is formed on a metal substrate and then covered with a silver protective layer. The simplest method for connecting RE-based superconducting wires to each other is by soldering, but in that case a contact resistance of about 10 ^-8 Ω is generated and it is difficult to set the ideal permanent current mode. Met.
Therefore, as a method of connecting the superconducting coils made of the RE superconducting wire with low resistance, a method of removing the metal film of the oxide superconducting wire and sintering the oxide superconducting cores has been proposed. (For example, refer to Patent Document 1).

Japanese Patent No. 3018534

However, as shown in FIG. 14, since the oxide superconducting film L1 of the oxide superconducting wire L, which is sintered and connected, is connected through the ceramics L2, the mechanical strength is poor, and it is suitable for applications such as magnet systems. When assembled or transported, it could be damaged by bending or impact.

Further, since a high temperature of about 800° C. is required for sintering the oxide superconducting film, it is necessary to draw a part of the long wire into the heating region of the furnace as a planned connection part. In that case, the entire coil cannot be put into the sintering furnace, so that it was necessary to pull out only the connecting portion for sintering.
Then, if there is a problem that the required performance does not appear after the sintered connection of the oxide superconducting film, or if the oxide superconducting film has a problem such as breakage, it is necessary to redo the connection, but the sintering connection process of the oxide superconducting film is the same. It has been found from experience that, if it is performed a plurality of times at the connection portion, the metal substrate in the connection portion of the superconducting wire rod is distorted due to thermal fatigue, resulting in deterioration of the superconducting characteristics of the connection portion.
Therefore, when reconnecting, it is necessary to cut off the portion that has undergone the sintering connection process and try sintering connection by making a neighboring superconducting wire material portion a new planned connection portion. Therefore, when connecting the oxide superconducting film, it was necessary to consider the possibility of redoing and secure a surplus length more than the length actually required for the sintering work before the sintering connection. ..
On the other hand, the RE superconducting wire has a tape shape and is weak in bending and bending in a specific direction. Therefore, it is preferable that the extra length part is mechanically fixed so that damage does not occur. At that time, it was necessary to take care so that the sintered joint was not damaged.

In addition, since the portion of the oxide superconducting film that is sintered and connected is a ceramic, its thermal conductivity is low, and if it changes to the normal conducting state for some reason, the resistance becomes extremely high. There was also a problem in that when the occurrence of the phenomenon occurred, it immediately became a hot spot and burned out.

As described above, an object of the present invention is to provide a superconducting wire connecting structure that effectively protects a connecting portion of a sintered superconducting wire.
Another object of the present invention is to provide a superconducting wire connecting structure that suitably protects an extra length portion of a superconducting wire that is sintered and connected.
Another object of the present invention is to provide a connection structure for a superconducting wire, which is capable of suitably protecting a connecting portion of a sintered and connected superconducting wire from burnout.

The invention according to claim 1 is
A tape-shaped base material having a superconducting conductor layer formed on one surface,
In a connection structure of a RE-based superconducting wire comprising a protective layer covering the base material,
A connection portion in which the superconducting conductor layer exposed from the protective layer of the two superconducting wires is sintered and connected ,
A frame member with a groove having a groove portion to which the connecting portion is fixed ,
A non-inductive winding frame member around which the extra length of one of the superconducting wires is wound,
It is characterized by having.

The invention according to claim 2 is the connection structure for the superconducting wire according to claim 1,
The grooved frame material includes a columnar portion,
The two superconducting wires connected by the connecting portion are wound around the columnar portion.

The invention according to claim 3 is the connection structure of the superconducting wire according to claim 1 or 2,
It is characterized in that the two superconducting wires are connected so as to be able to conduct at portions other than the connecting portion.

The invention according to claim 4 is the connection structure for a superconducting wire according to claim 2,
It is characterized in that the two superconducting wires are electrically connected to each other at a portion other than the connecting portion and wound around the grooved frame material.

The invention according to claim 5 is the connection structure for the superconducting wire according to claim 3 or 4,
The two superconducting wires are connected by a superconducting wire other than the two superconducting wires at a portion other than the connecting portion.

The invention according to claim 6 is the connection structure for a superconducting wire according to any one of claims 1 to 5,
It is characterized in that the groove portion has a resin or a low melting point metal.

The invention according to claim 7 is the connection structure for a superconducting wire according to any one of claims 1 to 6, wherein:
The two superconducting wires,
It is characterized in that the superconducting wires are connected so that the directions toward the connecting portion side in the longitudinal direction are the same.

According to the present invention, since the connecting portion of the two superconducting wire members is fixed in the groove portion of the grooved frame member, the periphery of the connecting portion is surrounded by the inner wall of the groove portion and the mechanical strength is kept high, and bending or impact ，It is possible to protect from other external forces and effectively reduce the occurrence of breakage.
Further, when the grooved frame member is configured to have a columnar portion, the superconducting wire can be held by winding, and the extra length portion of the superconducting wire can be protected from bending or bending in a specific direction. Become.
Further, in the case where two superconducting wires are connected so as to be able to conduct at a portion other than the connecting portion, when the transition to the normal conducting state occurs at the connecting portion, current may be released to the bypass connecting portion. Therefore, it is possible to suppress hot spots in the connection portion and reduce the occurrence of burnout.

It is a perspective view which shows the structure of RE type|system|group superconducting wire. It is a top view of the connection structure of the RE superconducting wire which is a first embodiment. It is a top view of the periphery of a sintered connection part. It is a perspective view of a frame material with a groove. It is a schematic block diagram of the electric current system which uses the superconducting coil which is 2nd embodiment. It is a schematic structure figure showing composition of a permanent current loop side of a current system. It is a perspective view of a 1st coil and a 2nd coil. It is a perspective view of a connector. FIG. 9A is a perspective view of the persistent current switch, and FIG. 9B is a sectional view of the persistent current switch. FIG. 10(A) is a perspective view of the superconducting coil unit, and FIG. 10(B) is a cross-sectional view showing a cross section passing through the center line of the coil. 11A is a plan view of the superconducting coil unit, and FIG. 11B is a partially enlarged view. It is a perspective view of a sinter connection part. FIG. 13(A) is a perspective view of the grooved frame material in which the RE-based superconducting wire is wound, and FIG. 13(B) is a perspective view of the grooved frame material in which the RE-based superconducting wire is not wound. Is. FIG. 14(A) is a side view of the sinter-connected oxide superconducting wire, and FIG. 14(B) is a perspective view.

[First embodiment]
A preferred first embodiment for carrying out the present invention will be described below with reference to the drawings. However, the embodiments described below are provided with various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.
The present embodiment relates to an RE-based superconducting wire connection structure 10 that enables connection of two RE-based superconducting wires 100, which are individually defined for use, as a superconducting wire in a superconducting state.

[RE superconducting wire]
FIG. 1 is a perspective view showing the structure of an RE-based superconducting wire 100 to be connected.
The RE-based superconducting wire 100 includes an intermediate layer 2 and an oxide on one main surface (hereinafter, referred to as a film-forming surface 11) in the thickness direction of a superconducting film-forming substrate 1 (hereinafter, referred to as a "substrate 1"). A superconducting conductor layer 3 and an internal protective layer 4 are laminated in this order, and an internal protective layer 4a is also formed on the surface opposite to the main surface of the base material 1. That is, the RE-based superconducting wire 100 has a laminated structure including the inner protective layer 4, the base material 1, the intermediate layer 2, the oxide superconducting conductor layer 3 (hereinafter referred to as “superconducting conductor layer 3”), and the inner protective layer 4a. In addition, an external protective layer 5 (stabilizing layer) that covers the periphery of this laminated structure is provided.
In the following, the inner protective layers 4, 4a and the outer protective layer 5 may be collectively referred to as "protective layer".
Further, except for FIG. 1, the illustration of the intermediate layer 2, the inner protective layer 4, and the inner protective layer 4a of the RE-based superconducting wire 100 is omitted.

As the base material 1, a tape-shaped low magnetic metal substrate or ceramic substrate is used. As the material of the metal substrate, for example, a metal such as Co, Cu, Cr, Ni, Ti, Mo, Nb, Ta, W, Mn, Fe, Ag or the like or an alloy thereof having excellent strength and heat resistance is used. .. In particular, it is preferable to use Ni-based alloys such as Hastelloy (registered trademark) and Inconel (registered trademark), or Fe-based alloys such as stainless steel from the viewpoint of excellent corrosion resistance and heat resistance.
Further, various ceramics may be arranged on these various metal materials. Further, as the material of the ceramic substrate, for example, MgO, SrTiO ₃ , or yttrium-stabilized zirconia is used. Besides, sapphire may be used as the base material.
The thickness of the base material 1 is about 50 μm (note that the numerical value of the thickness is an example and is not limited to this. The same applies to the thickness of each of the other layers of the RE-based superconducting wire 100).

The film forming surface 11 is a substantially smooth surface, and it is preferable that the film forming surface 11 has a surface roughness of 10 nm or less.
The surface roughness is the arithmetic average roughness Ra in the “amplitude average parameter in the height direction” of the surface roughness parameters specified in JIS B-0601-2001.

The intermediate layer 2 is a layer for realizing, for example, high biaxial orientation in the superconducting conductor layer 3. Such an intermediate layer 2 has a physical property value such as a coefficient of thermal expansion or a lattice constant that is intermediate between that of the base material 1 and that of the superconductor forming the superconducting conductor layer 3.
The intermediate layer 2 may have a single-layer structure or a multi-layer structure. In the case of a multilayer structure, the number and type of layers are not limited, but a bed layer containing amorphous Gd ₂ Zr ₂ O _7-δ (δ is an oxygen nonstoichiometric amount), Al ₂ O ₃ or Y ₂ O _{3 and the} like. And a forced orientation layer containing crystalline MgO or the like and formed by the IBAD (Ion Beam Assisted Deposition) method, and an LMO layer containing LaMnO _3+δ (δ is an oxygen non-stoichiometric amount). May be. A cap layer containing CeO ₂ or the like may be further provided on the LMO layer.
The thickness of each layer is 30 nm for the LMO layer, 40 nm for the MgO layer as the forced orientation layer, 7 nm for the Y ₂ O ₃ layer as the bed layer, and 80 nm for the Al ₂ O ₃ layer.

The superconducting conductor layer 3 is laminated on the surface of the intermediate layer 2. The superconducting conductor layer 3 preferably contains a high temperature oxide superconductor, particularly a copper oxide superconductor. As the copper oxide superconductor, REBa ₂ Cu ₃ O _7-δ (hereinafter referred to as RE superconductor) as a high temperature superconductor is preferable. RE in the RE-based superconductor is a single rare earth element or a plurality of rare earth elements such as Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu. Further, δ is an oxygen non-stoichiometric amount, for example, 0 or more and 1 or less, and it is more preferable that it is closer to 0 from the viewpoint of high superconducting transition temperature. Note that the oxygen nonstoichiometric amount may take a negative value, that is, a negative value, when the high-pressure oxygen annealing or the like is performed using a device such as an autoclave.
The superconducting conductor layer 3 has a thickness of about 1 μm.

Internal protective layers 4 and 4a are laminated on the surface of the superconducting conductor layer 3 (the surface opposite to the intermediate layer 2) and the surface of the base material 1 opposite to the main surface 11, respectively. The inner protective layers 4 and 4a are metal layers having good conductors, and preferably a metal containing at least one of Ag, Au or Cu. Here, the case where the inner protective layers 4 and 4a are Ag is exemplified.
The internal protective layer 4 on the superconducting conductor layer 3 side has a thickness of about 2 μm, the internal protective layer 4a on the base material 1 side has a thickness of about 1.8 μm, and the internal protective layer 4a on the base material 1 side is formed thinner. There is.

The outer protective layer 5 has the upper and lower surfaces and the left and right surfaces in FIG. 1 of the laminated body including the inner protective layer 4, the base material 1, the intermediate layer 2, the superconducting conductor layer 3, and the inner protective layer 4a of the RE superconducting wire 100. It is formed so as to cover the entire length.
The outer protective layer 5 is formed to have a thickness of about 20 μm on each side.
The outer protective layer 5 is a silver stabilizing layer made of Ag. The stabilizing layer may have a single-layer structure or a multi-layer structure. In the case of a multi-layer structure, the number and type of layers are not limited.
The external protective layer 5 may be a copper stabilizing layer formed of copper, or may have a structure in which a copper stabilizing layer is sequentially laminated on a silver stabilizing layer.

[Outline of connection structure of RE superconducting wire]
FIG. 2 is a plan view of the connection structure 10 of the RE-based superconducting wire.
The RE-based superconducting wire connecting structure 10 (hereinafter, simply referred to as “connecting structure 10”) is a sintered connecting part 6 as a connecting part between the superconducting conductor layers 3 exposed from the protective layer of the two RE-based superconducting wires 100. And a grooved frame member 20 having a groove portion 211 in which the sintered connection portion 6 is embedded, and a non-inductive winding frame member 30 around which an extra length portion of one RE-based superconducting wire 100 is wound.

[Sintered connection]
FIG. 3 is a plan view of the periphery of the sintered connection portion 6.
As described above, the two RE-based superconducting wire rods 100 to be connected have their respective uses (for example, superconducting coils) individually determined, and the sintered connection part is used from the part used for the uses. In order to form 6, the tips of the portions that are pulled out with an extra length are sintered and connected. The extra length portion of each RE-based superconducting wire 100 has a length sufficient for avoiding the influence of the high temperature during the sintering operation of the sintering connection portion 6 and a plurality of sintering operations (in the case of a connection failure, the tip end). The length is secured in consideration of cutting off the sintered part of and performing the sintering work again.
In the sintered connection portion 6, the protective layer is removed at a fixed length at each connection end portion of the RE-based superconducting wire 100, and the base material 1 and the superconducting conductor layer 3 that are exposed are separated from each other. It is formed by performing sintering connection in a state where the positions of the tip portions are aligned and the exposed surfaces of the superconducting conductor layer 3 are bonded face to face.
Further, in the sintered connection portion 6, the two RE-based superconducting wires 100 are connected so that the directions toward the sintered connection portion 6 side in the longitudinal direction of the RE-based superconducting wire material are the same.

The MOD method (Metal Organic Deposition method/organic metal deposition method) is adopted for the sintering connection of the RE superconducting wire 100.
The MOD liquid is filled between the exposed surfaces of the two superconducting conductor layers 3 and only the connecting ends of the two RE-based superconducting wires 100 and their peripheral portions are maintained while maintaining a state in which the exposed surfaces are bonded to each other. On the other hand, calcination is performed in a temperature range of 400°C to 500°C in an N ₂ +O ₂ gas atmosphere, and 760°C to 800°C in an Ar+O ₂ gas atmosphere while pressurizing each other. After the main firing is performed in the temperature range of 1, the oxygen annealing is performed in the oxygen atmosphere in the temperature range of 350° C. or higher and 500° C. or lower.
In the above MOD liquid, for example, RE (Y (yttrium), Gd (gadolinium), Sm (samarium) and Ho (holmium) and other rare earth elements), Ba and Cu in a ratio of about 1:2:3. The acetylacetonate-based MOD solution contained in 1) is used.
Thereby, the superconducting conductor layers 3 of the two RE-based superconducting wires 100 are connected in a superconducting state, and the sintered connection portion 6 is formed.

[Grooved frame material]
FIG. 4 is a perspective view of the frame member 20 with grooves.
As shown in FIGS. 2 to 4, the grooved frame member 20 includes a columnar columnar portion 21 and a flange portion 22 formed on the outer periphery of the lower portion (one end side in the centerline direction) of the columnar portion 21. It has and.
Since the RE-based superconducting wire 100 is assumed to be used at extremely low temperatures, the grooved frame member 20 has a frame material such as GFRP (Glass Fiber Reinforced Plastics), copper, aluminum, etc., which cracks at low temperatures. It is integrally formed of a material that is difficult to do.

A straight groove portion 211 is formed on the upper surface of the cylindrical portion 21 at a position slightly deviated from the center from the outer peripheral surface toward the inside, and the entrance entering the groove portion 211 from the outer peripheral surface has a rounded corner. A curved arc portion 212 is formed. In addition, a mounting hole 25 is formed in the center of the column-shaped portion 21 so as to vertically penetrate therethrough to fix the grooved frame member 20 to the outside.
Then, the sintered connection portions 6 of the two RE-based superconducting wires 100 are inserted over the entire length in the groove portion 211 formed in the columnar portion 21 of the grooved frame member 20, and the sintered portion and the groove portion 211 are sintered together. A filler 23 is filled between the connecting portions 6, and the sintered connecting portion 6 is embedded in the groove 211.
As the filler 23, a low melting point metal such as solder, resin (for example, epoxy resin), paraffin, or the like is used.

In addition, the extra length portion of the two RE-based superconducting wires 100 other than the sintered connection portion 6 is curved along the arc portion 212, and is wound around the outer periphery of the cylindrical portion 21 on the upper surface of the flange portion 22. Has been done. The outer diameters of the cylindrical portion 21 and the arc portion 212 are set so as not to fall below the minimum bend diameter of the RE-based superconducting wire 100. For example, if the RE-based superconducting wire 100 has an allowable minimum bending diameter of 11 [mm], the outer diameter (radius) of the cylindrical portion 21 and the arc portion 212 is set to a value of 5.5 [mm] or more. ..
A strip-shaped insulating material 24 is arranged on the outer peripheral surface side of the two RE-based superconducting wires 100 in a wound state, and is wound together with the two RE-based superconducting wires 100. As the strip-shaped insulating material 24, a polyimide tape, a fluororesin tape, or a high resistance metal tape such as stainless steel is used.
As a result, the two RE-based superconducting wire rods 100 are in close contact with each other, but the two RE-based superconducting wire rods 100 that are wound a plurality of times are insulated every turn, and the generation of induced current is suppressed. It has a structure that

Further, in the two RE-based superconducting wires 100, a bypass connecting portion 7 that connects the superconducting conductor layers 3 to each other so as to be conductive with low resistance is formed in a portion other than the sintered connecting portion 6. The bypass connection portion 7 is formed by welding the surfaces of the outer protective layer 5 of each RE-based superconducting wire 100 with a brazing material made of a good conductor such as solder.

In the case of a structure in which one RE-based superconducting wire 100 is conductively connected to the other RE-based superconducting wire 100 via the sintered connecting portion 6 like the above-described connecting structure 10, the sintered connecting portion is caused by some cause. When the superconducting conductor layer 3 in 6 transitions from the superconducting state to the normal conducting state, the resistance becomes high and heat is generated due to overcurrent. Since the metal protective layers 4 and 5 do not exist around the superconducting conductor layer 3 in the sintered connection portion 6, there is no escape place for current and heat, and there is a risk of burning into a hot spot.
Therefore, by providing the bypass connection portion 7 in a portion other than the sintered connection portion 6, a current is caused to flow through the bypass connection portion 7 to suppress hot spot formation in the sintered connection portion 6.

The bypass connection portion 7 formed for the above purpose is desired to have sufficiently low resistance and high current capacity. On the other hand, when the above-mentioned Ni alloy or the like is used as the material of the base material 1 of the RE-based superconducting wire 100, the resistance is relatively high, so that one RE-based superconducting wire 100 in the bypass connection portion 7 is used. So that the base material 1 does not exist between the superconducting conductor layer 3 and the superconducting conductor layer 3 of the other RE-based superconducting wire 100. It is desirable to bypass the faces together.

2 illustrates the case where the bypass connection portion 7 is formed in the winding portion of the RE-based superconducting wire 100 wound around the grooved frame member 20, but in the two RE-based superconducting wire 100. The bypass connection portion 7 may be formed in a portion that is not wound around the grooved frame member 20. In that case, it is desirable that the portions of the two RE-based superconducting wires 100 that are not wound around the grooved frame member 20 except the bypass connection portion 7 be insulated from each other. For insulation between the two, it is desirable to interpose the above-mentioned insulating material 24, for example.

The extra length portions of the two RE-based superconducting wires 100 wound around the frame member 20 with grooves may be fixed with a curable resin such as epoxy so as to maintain the wound state. Alternatively, it may be fixed by a C-shaped frame fitted to the outer circumference of the two wound RE-based superconducting wires 100.

[Inductive winding frame material]
The non-inductive winding frame material 30 includes two RE-based superconducting wires 100 wound in the grooved frame material 20 when the extra lengths of the RE-based superconducting wires 100 are different from each other or one RE-based superconducting wire 100 wound inside. Is a frame material for further winding the surplus portion of only one RE-based superconducting wire 100 when the surplus portion cannot be wound around the grooved frame member 20 due to the diameter difference.

As shown in FIG. 2, the non-induction winding frame member 30 includes a columnar cylindrical portion 31 and a flange portion 32 formed on the outer periphery of the lower portion (one end side in the centerline direction) of the cylindrical portion 31. Equipped with. In addition, a mounting hole 35 is formed in the center of the columnar portion 31 so as to vertically penetrate therethrough and fix the non-inductive winding frame member 30 to the outside.
This non-inductive winding frame member 30 is also integrally formed of GFRP, copper, aluminum or the like, assuming use at extremely low temperatures.

The cylindrical portion 31 has a shape in which a part of the outer circumference is cut out, and the shaft portion 33 for folding back one RE-based superconducting wire 100 is formed in the cutout portion.
That is, the RE-based superconducting wire 100 having an excess length portion that cannot be completely wound around the grooved frame member 20 is folded back so that the intermediate portion of the excess length portion that cannot be wound is wound around the outer periphery of the shaft portion 33, and has a cylindrical shape. The RE superconducting wire 100 is doubly wound around the outer peripheral surface of the portion 31.

The same band-shaped insulating material 34 as the above-described insulating material 24 is also arranged on the outer peripheral surface side of the double wound RE superconducting wire 100 and is wound together with the double RE superconducting wire 100.
As a result, the double-wound RE superconducting wire 100 is also insulated for each turn, and the generation of induced current can be suppressed.

The extra length of the RE superconducting wire 100 wound around the non-inductive winding frame material 30 is fixed with a curable resin such as epoxy or a C-shaped frame in order to maintain the winding state. May be.

[Technical effects of connection structure]
In the connection structure 10 for the RE-based superconducting wire, since the sintered connecting parts 6 of the two RE-based superconducting wires 100 are embedded in the groove portion 211 of the grooved frame member 20, the periphery of the sintered connecting part 6 is The mechanical strength is kept high by being surrounded by the inner wall of the groove 211, and it is possible to protect from bending, impact, and other external force, and effectively reduce the occurrence of breakage.

Further, the grooved frame member 20 includes the columnar portion 21, and since the two RE-based superconducting wire rods 100 connected by the sintered joint portion 6 are wound around the columnar portion 21, the sintered joint portion 6 is formed. By winding the extra length portion of the RE-based superconducting wire 100 that has been pulled out for the sintering work of No. 3, it is possible to protect the extra length portion from bending or bending in a specific direction.
Further, the extra length portion of the RE-based superconducting wire 100 can be stably restrained by winding, the stress and the load applied to the sintered connection portion 6 side can be suppressed, and the sintered connection portion 6 can be protected. It is possible to plan.
In addition, since the circular arc portion 212 is formed at the entrance of the groove portion 211 of the cylindrical portion 21, the bending applied to the RE-based superconducting wire 100 wound around the groove portion 211 is relaxed, and the RE-based superconducting wire 100 is wound. It becomes possible to protect.

Further, in the connecting structure 10, the two RE-based superconducting wires 100 are connected to the bypass connecting portion 7 so as to be able to conduct in a portion other than the sintering connecting portion 6, so that the sintered connecting portion 6 may have some cause for some reason. When the superconducting conductor layer 3 transitions from the superconducting state to the normal conducting state, the current can be released to the bypass connection portion 7, the hot spot of the sintered connection portion 6 can be suppressed, and the occurrence of burnout can be reduced. It will be possible.
In particular, since the bypass connecting portion 7 is provided in the winding portion where the two RE-based superconducting wires 100 are stably restrained by the columnar portion 21, the bypass connecting portion 7 is protected from stress and load and is prevented from being damaged. It is possible to reduce the occurrence.

Further, since the connection structure 10 includes the non-inductive winding frame member 30, when only one of the two RE-based superconducting wire rods 100 has an extra length portion longer than the other, the extra length portion is wound. It can be restrained in a rotated state, and the extra length portion can be protected from bending or bending in a specific direction.

[Second embodiment]
A current system 200 using a superconducting coil to which the connection structure 10 of the RE-based superconducting wire described above is applied will be described with reference to the drawings.

[Current system using superconducting coil]
FIG. 5 is a schematic configuration diagram of a current system 200 using a superconducting coil.
A current system 200 using the above superconducting coils (hereinafter referred to as “current system 200”) includes a plurality (n) of superconducting coils 40 connected in series, and a current is passed through these superconducting coils 40 to generate an excitation loop Er. And a permanent current switch 60 forming a permanent current loop Pr in which the power source 201 does not intervene for a plurality (n) of superconducting coils 40 connected in series.
The permanent current switch 60 and the plurality of superconducting coils 40 forming the permanent current loop Pr are all connected by the RE superconducting wire 100, and they are cooled to a cryogenic temperature to bring the RE superconducting wire 100 into a superconducting state. A refrigerator (not shown) is provided for this purpose.
Further, the connection structure 10 of the RE-based superconducting wire described above is applied to the connecting portions of the respective portions of the permanent current switch 60 and the plurality of superconducting coils 40 that form the above-mentioned permanent current loop.

In the current system 200, a power supply 201 first causes a current to flow through each superconducting coil 40 to form an excitation loop Er.
Then, when the plurality of superconducting coils 40 and the persistent current switch 60 are cooled to a temperature at which they are in the superconducting state, the power supply 201 is turned off. As a result, a permanent current loop Pr can be formed between the plurality of superconducting coils 40 and the persistent current switch 60.
The permanent current loop Pr formed by the permanent current switch 60 and the superconducting coil 40 is established by the connection structure 10 described above without passing through the normal conducting resistance, and a permanent current system having high temporal stability can be manufactured.
Each configuration of the current system 200 using such a superconducting coil will be described below.

[Superconducting coil]
FIG. 6 is a schematic structural diagram showing the configuration of the current system 200 on the permanent current loop Pr side.
Each superconducting coil 40 is a solenoid coil in which the RE-based superconducting wire 100 is wound. One end of the RE-based superconducting wire 100, which is a winding, is pulled out from the inner circumference of the coil, and the other end of the RE-based superconducting wire 100 is It is pulled out from the outer circumference of the coil.
Then, as shown in the figure, the plurality of superconducting coils 40 (first coil 401 to nth coil 40n) are concentric and are sequentially arranged from the inner side toward the outer side in the radial direction. That is, the outer superconducting coil 40 has a larger diameter, and the inner superconducting coil 40 is accommodated on the inner peripheral side.

Here, the structure of the superconducting coil 40 will be described in more detail by taking the innermost first coil 401 and the second coil 402 arranged outside thereof as an example. FIG. 7 is a perspective view of the first coil 401 and the second coil 402.
As shown in the drawing, the first coil 401 is connected to a cylindrical coil winding frame 411, an RE-based superconducting wire 100 that is wound around the coil winding frame 411 in a plurality of layers from the inside, and a refrigerator (not shown). And a metal sleeve 421 for cooling the wound RE-based superconducting wire 100.
The second coil 402 includes a cylindrical coil winding frame 412 arranged on the outer circumference of the metal sleeve 421, an RE-based superconducting wire 100 wound on the coil winding frame 411 in a plurality of layers from the inside, It is provided with a metal sleeve (not shown) that cools the wound RE superconducting wire 100.

The coil winding frames 411 and 412 are integrally formed of a material such as GFRP, copper, or aluminum that is unlikely to be cracked at low temperatures. However, when using a good conductor as the bobbin, it is desirable to make a cut in the axial direction of the bobbin as a measure against eddy current.
The metal sleeves of the coils 401 and 402 are made of oxygen-free copper having high heat conductivity. The metal sleeve has a structure in contact with the coil winding frames 411, 412 and the wound RE-based superconducting wire 100, and the contact surface with these is coated with grease to enhance the heat transfer property and improve the coil winding 411. , 412 and the wound RE-based superconducting wire 100 are improved in cooling efficiency. In addition, a polyimide film for insulation is attached to the contact surface of the metal sleeve with the RE-based superconducting wire 100.

One end of the RE-based superconducting wire 100 of the first coil 401 is drawn out from the inner circumference side of the coil (not shown in FIG. 7) and is branched to the power supply 201 side and the persistent current switch 60 side. The other end of the RE-based superconducting wire 100 is pulled out from the outer peripheral side of the coil to the upper side in FIG. 7 (the lower side in FIG. 6).
One end of the RE-based superconducting wire 100 of the second coil 402 is pulled out from the inner circumference side of the coil to the upper side in FIG. 7 (downward in FIG. 6), and the other end of the RE-based superconducting wire 100 is the outer circumference of the coil. It is pulled out from the side upward (downward in FIG. 6) in FIG. 7 (not shown).
The other end of the RE-based superconducting wire 100 drawn to the outer circumference of the first coil 401 and the one end of the RE-based superconducting wire 100 drawn to the inner circumference of the second coil 402 are the above-described RE-based superconducting wire. They are connected by a connector 110 (which will be described later) to which the connection structure 10 is applied.
Reference numeral 112 in FIG. 7 is a columnar guide (described later) that individually guides the other end of the RE-based superconducting wire 100 of the first coil 401 and the one end of the RE-based superconducting wire 100 of the second coil 402. ..

Similar to the second coil 402, the other superconducting coil 40 outside the second coil 402 also includes a coil winding frame around which the RE-based superconducting wire 100 is wound and a metal sleeve, and is wound RE. Both the one end and the other end of the RE superconducting wire 100 are drawn upward (downward in FIG. 6) in FIG. 7, and the one end of the RE superconducting wire 100 wound between adjacent superconducting coils 40 and The other end is connected by a connector 110 (described later).
Further, in the n-th coil 40n arranged on the outermost side, one end portion of the RE-based superconducting wire 100 is pulled out from the inner peripheral side of the coil to the upper side in FIG. The other end of 100 is drawn out from the outer peripheral side of the coil and is branched to the power supply 201 side and the permanent current switch 60 side.
Also, with respect to the second coil 402 to the nth coil 40n, one end and the other end of the RE-based superconducting wire 100 are connected by the connector 110 between adjacent coils.

[Connector]
FIG. 8 is a perspective view of the connector 110.
The connector 110 includes a connection structure 10 that holds the sintered connection part 6 of the RE-based superconducting wire 100 drawn out from the two superconducting coils 40, a cooling plate 111 that supports each component of the connection structure 10, and a cooling plate 111. It is provided with two columnar guides 112 formed integrally with the plate 111 and extended from the cooling plate 111.

The cooling plate 111 and the columnar guide 112 are made of oxygen-free copper having high heat conductivity, and are connected to a refrigerator (not shown) to cool the RE-based superconducting wire 100.
The cooling plate 111 is a circular flat plate, and the connection structure 10 is attached to the upper surface thereof. The shape of the cooling plate 111 is not limited to the circular shape, and may be any shape.
The grooved frame member 20 and the non-inductive winding frame member 30 of the connection structure 10 are coated with grease on the contact surfaces with the cooling plate 111, and the RE-based superconducting wire 100 wound around these frame members 20 and 30. Cooling efficiency is improved.
Further, the grooved frame member 20 and the non-induction winding frame member 30 are fastened and fixed to the cooling plate 111 through mounting holes 25 and 35 by bolts (not shown). By loosening the bolts, the respective frame members 20 and 30 can be rotated around the bolts, and the winding amount can be adjusted according to the length of the extra length portion of the RE-based superconducting wire 100 to be wound. ..

The extra length portion of the RE-based superconducting wire 100 drawn out from the two superconducting coils 40 is individually spirally wound around each columnar guide 112, and burned by the sintering connection portion 6 in the connection structure 10 on the cooling plate 111. Connected and connected.
After the extra length of each RE-based superconducting wire 100 is adjusted and wound around each part, it is desirable to solidify the RE-based superconducting wire 100 and each of the frame members 20 and 30 with an epoxy resin or the like so as not to separate.

Grease may be applied between each columnar guide 112 and each RE-based superconducting wire 100 to enhance cooling efficiency.
Further, on the surface of the cooling plate 111 and the columnar guide 112, a polyimide film for insulating the RE-based superconducting wire 100 is attached to a portion in contact with the RE-based superconducting wire 100.

By extending these columnar guides 112 longer, it is possible to reduce the influence of the magnetic field from each superconducting coil 40. When the influence of the magnetic field increases, the current value that can be passed through the RE-based superconducting wire 100 decreases, and the RE-based superconducting wire 100 may be separated from the winding position due to the influence of the magnetic field. By extending it for a long time, these can be suppressed.

By the connector 110, the RE-based superconducting wire rods 100 of the respective superconducting coils 40 can be connected to each other by sintering connection which enables superconducting connection.
Further, the sintered connection portion 6 can stably maintain the connected state in the state where the mechanical strength is secured by the grooved frame member 20, and it is possible to reduce failure and damage.
Further, the extra length portion of the RE-based superconducting wire 100 of each superconducting coil 40 is held in a wound state by the respective frame members 20 and 30, and is protected from twisting, bending, etc., so that a stable connected state is maintained and a failure or failure occurs. Damage can be reduced.

[Permanent current switch]
9A is a perspective view of the persistent current switch 60, and FIG. 9B is a sectional view of the persistent current switch 60.
The permanent current switch 60 has one end of the RE-based superconducting wire 100 drawn from the inner peripheral side of the first coil 401 and the other end of the RE-based superconducting wire 100 drawn from the outer peripheral side of the nth coil 40n. It is a switch that is provided so as to be connected and that switches between maintaining and canceling the persistent current loop Pr that flows in the circuit by the endless annular RE-based superconducting wire 100 formed by this.

The persistent current switch 60 includes a connection structure 10 for connecting and holding the RE-based superconducting wire rods 100 individually drawn out from the first coil 401 and the n-th coil 40n by sintering connection, and each structure of the connection structure 10. A cooling plate 61 for supporting the cooling plate 61, a column 62 integrally formed with the cooling plate 61, and provided upright from the cooling plate 61, a thermal resistance portion 63 provided on the outer peripheral surface of the column 62, and a column 62. Two columnar guides 64 that are integrally formed and extend from the upper end of the pillar 62, and a heating unit 65 that heats the RE-based superconducting wire 100 that is wound around the outer periphery of the thermal resistance portion 63 of the pillar 62. It has and.

The cooling plate 61, the support column 62, and the columnar guide 64 are integrally formed of oxygen-free copper having high heat conductivity, and the cooling plate 61 is connected to a refrigerator (not shown) to cool the RE-based superconducting wire 100.
The cooling plate 61 is a circular flat plate, and the connection structure 10 is attached to the upper surface thereof. The cooling plate 61 is not limited to the circular shape and may have any shape.

The grooved frame member 20 and the non-inductive winding frame member 30 of the connection structure 10 are coated with grease on their contact surfaces with the cooling plate 61 to enhance the cooling efficiency.
Further, the grooved frame member 20 and the non-inductive winding frame member 30 are fastened and fixed with bolts through the mounting holes 25 and 35, and the winding amount of the RE-based superconducting wire 100 can be adjusted. It is the same.

The extra length portion of each RE-based superconducting wire 100 drawn out from the first coil 401 and the nth coil 40n is individually spirally wound around each columnar guide 64, and two RE-based superconducting wires 100 are lined up. In this state, it is spirally wound around the outer circumference of the heat resistance portion 63 provided on the outer circumference of the support column 62, and is sintered and connected by the sintering connection portion 6 in the connection structure 10 on the cooling plate 61.
Grease may be applied between each columnar guide 64 and each RE-based superconducting wire 100 to enhance the cooling efficiency.
Further, on the surface of the cooling plate 61 and the columnar guide 64, a polyimide film for insulating the RE-based superconducting wire 100 is attached to a portion in contact with the RE-based superconducting wire 100.
Further, the RE-based superconducting wire 100 wound around each part is fixed by an epoxy resin together with each of the frame members 20 and 30.

The thermal resistance portion 63 is formed of a high thermal resistance metal such as SUS316 or a high thermal resistance material such as FRP. The heating unit 65 is provided so as to surround the thermal resistance unit 63, and the portion of each RE-based superconducting wire 100 wound around the thermal resistance unit 63 is heated by the heater of the heating unit 65 from the outer peripheral side thereof. It can be heated. Further, since the heat resistance portion 63 makes it difficult for heat to be transmitted to the support column 62, the RE-based superconducting wire 100 can be effectively heated.

The permanent current switch 60 can cool the entire permanent current switch 60 and the RE-based superconducting wire 100 by cooling the cooling plate 61 with a refrigerator, and bring the RE-based superconducting wire 100 into a superconducting state.
Then, in this superconducting state, the RE-based superconducting wire rods 100 of all the superconducting coils 40 are connected in an endless loop, and the permanent current loop Pr can be formed.
Further, in order to cancel the persistent current loop Pr, the temperature of the RE-based superconducting wire 100 is raised by the heater of the heating unit 65, and the superconducting state is switched to the normal conducting state. As a result, a large normal conducting resistance is generated in the portion of each RE-based superconducting wire 100 wound around the thermal resistance portion 63, and the permanent current loop Pr is released.
In this way, the permanent current switch 60 includes one end of the RE-based superconducting wire 100 drawn from the inner circumference side of the first coil 401 and one of the RE-based superconducting wire 100 drawn from the outer circumference side of the nth coil 40n. The connection state with the other end and the disconnection state are switched.

Since the current in the permanent current loop Pr is cut off according to the above principle, it is necessary to sufficiently secure the normal conduction resistance due to the extra length portion wound around the thermal resistance portion 63 in the RE-based superconducting wire 100. For this reason, it is necessary to sufficiently increase the wire length and the number of turns of the extra length portion wound around the thermal resistance portion 63 in the RE superconducting wire 100, which causes the permanent current switch 60 to have a large inductance. There may also be adverse effects.
Therefore, as shown in FIG. 9(A), when two RE-based superconducting wires 100 in which currents flow in opposite directions are lined up and wound in a spiral state with a gap for each circumference, a non-induction winding state is obtained. Becomes This reduces the inductance of the persistent current switch 60.

In addition, the permanent current switch 60 has two RE-based superconducting wires 100 drawn out from the two superconducting coils 40 wound around a thermal resistance portion 63 provided with a heating portion 65, and its tip end is connected by the connection structure 10. With this configuration, it is possible to connect the two RE-based superconducting wires 100 drawn out from the two superconducting coils 40 with one connection structure 10, simplifying the configuration of the persistent current switch 60, and reducing the number of parts, etc. Has achieved a reduction.

[Third embodiment]
Regarding superconducting coil unit 300 to which RE-based superconducting wire connecting structure 10A (hereinafter referred to as "connecting structure 10A") is applied as another embodiment, which is partially different in configuration from RE-based superconducting wire connecting structure 10 described above. A description will be given with reference to the drawings.

[Schematic configuration of superconducting coil unit]
10(A) is a perspective view of the superconducting coil unit 300, FIG. 10(B) is a sectional view showing a cross section passing through the center line of the coil, FIG. 11(A) is a plan view of the superconducting coil unit 300, and FIG. ) Is a partially enlarged view.
The superconducting coil unit 300 has two sets of double pancake coils 302 in which two RE pan-shaped superconducting wires 100 wound in the coil radial direction are laminated in the coil axial direction, so-called pancake coils 301 are connected in series. Further, a holding frame 310 for storing and holding these two sets of double pancake coils 302, and a tip portion of a surplus portion of the RE-based superconducting wire 100 individually drawn from the two sets of double pancake coils 302 are baked. The connecting structure 10A for connecting and connecting and the support plate 320 which supports the connecting structure 10A are provided.
In the following description, the same components as those of the connection structure 10 described above will be denoted by the same reference numerals and redundant description will be omitted.

[Double pancake coil]
The two pancake coils 301 forming the double pancake coil 302 are arranged in a single coil winding frame 303 so as to be aligned in the direction of the center line thereof. Further, the RE-based superconducting wire 100 forming these two pancake coils 301 is connected at the innermost peripheral portion, and the two pancake coils 301 are formed from one RE-based superconducting wire 100.
The two sets of double pancake coils 302 to be connected are wound so that one side has the superconducting layer inside and the other has the superconducting layer outside.

[Holding frame]
The holding frame 310 is configured by concentrically connecting two cases 311 that surround one double pancake coil 302 from the outer periphery and both sides in the coil center line direction.
In addition, the holding frame 310 is provided with slit-shaped openings 312 that lead out both ends of the RE-based superconducting wire 100 that forms each double pancake coil 302 to the outside.
The edge portion of the opening portion 312 is formed in a peripheral surface shape, and protects the RE-based superconducting wire 100 to be drawn out so as not to be bent at an allowable minimum bending radius or less.

One end of each of the two RE-based superconducting wires 100 drawn out from each of the two double pancake coils 302 through the opening 312 wraps around the outer peripheral surface of the holding frame 310 while maintaining a parallel state. And the connection structure 10A supported on one surface of the support plate 320 integrally attached to the holding frame 310.
The holding frame 310 and the support plate 320 are integrally formed of, for example, a material such as GFRP (Glass Fiber Reinforced Plastics), copper, or aluminum that is unlikely to crack at low temperatures.
The other ends of the two RE-based superconducting wire rods 100, which are respectively pulled out from the two double pancake coils 302, are led out from the opening 312 and are connected to other configurations depending on the application of the superconducting coil. ..

[Support plate]
The support plate 320 is a flat plate that is perpendicular to the coil center line direction, and the other ends of the two RE-based superconducting wires 100 that are respectively drawn out from the two double pancake coils 302 are parallel and edgewise. With respect to the holding frame 310, one side of the supporting plate 320 (the supporting surface of the connection structure 10A) is closer to the supporting plate 320 with respect to the holding frame 310 so that the RE-based superconducting wire is not bent. It is arranged so as to match the position of the side end portion of 100 on the side of the support plate 320.

[Connection structure of RE superconducting wire]
The connection structure 10A connects the superconducting conductor layers 3 exposed from the protective layer at one end of the two RE-based superconducting wires 100 that are respectively drawn out from the two double pancake coils 302 by another RE-based superconducting wire 100A. A sinter connection part 6A, a grooved frame member 20A having a groove part 211A in which the sinter connection part 6A is embedded, and a non-inductive winding frame member 30 around which an extra length portion of one RE-based superconducting wire 100 is wound. Equipped with.

[Sintered connection]
FIG. 12 is a perspective view of the sintered connection portion 6A.
In each double pancake coil 302, the two RE-based superconducting wires 100 are individually wound in a direction in which the superconducting conductor layer 3 is radially outward and inward with respect to the base material 1. When the RE-based superconducting wire 100 is pulled out from the opening 312 of the holding frame 310, the direction of one RE-based superconducting wire 100 is reversed, and the superconducting conductor layer 3 is in the outer side in the radial direction. The superconducting conductor layer 3 is arranged on the same surface side of the base material 1 in each of the extra length portions of the two RE-based superconducting wires 100 that have been pulled out to the connection structure 10 side. Then, another RE-based superconducting wire 100A is bridge-connected to the superconducting conductor layer 3 which is exposed by removing the protective layer of each RE-based superconducting wire 100.

Another RE-based superconducting wire 100A has the same structure as the two RE-based superconducting wires 100, extends in a direction orthogonal to these two RE-based superconducting wires 100, and has two RE-based superconducting wires 100. Are connected to the superconducting conductor layer 3 in a suspended state.
In another RE-based superconducting wire 100A, the protective layer is removed at both ends thereof to expose the superconducting conductor layer 3, and each of the superconducting conductor layers 3 exposed at both ends is a superconducting conductor of two RE-based superconducting wires 100. The layers are individually sintered and connected by the MOD method so as to face the layer 3.

[Grooved frame material]
FIG. 13(A) is a perspective view of the grooved frame member 20A in which the RE-based superconducting wire 100 is wound, and FIG. 13(B) is a grooved frame member in which the RE-based superconducting wire 100 is not wound. It is a perspective view of 20A.
As shown in these figures, the grooved frame member 20A includes a columnar columnar portion 21A and a flange portion 22A at the center of the outer peripheral surface of the columnar portion 21A in the centerline direction.
The grooved frame member 20A is also integrally formed of a frame material such as GFRP, copper, or aluminum, which is unlikely to crack at low temperatures.

The columnar portion 21A is supported on one surface of the support plate 320 such that the centerline direction thereof is parallel to the coil centerline direction of the double pancake coil 302. The columnar portion 21A is the same as the grooved frame member 20 described above in that the columnar portion 21A is fastened and fixed by a bolt that is passed through a mounting hole 25A formed through the center of the columnar portion 21A and the rotation thereof can be adjusted.

The cylindrical portion 21A is formed with a straight slit-shaped groove portion 211A penetrating from one surface to the back surface thereof, and the above-mentioned sintered connection portion 6A is inserted into the groove portion 211A and the filler 23 is filled in the gap. The sintered connection portion 6A is filled and is embedded in the groove portion 211A.

The two RE-based superconducting wires 100 connected by the sintered connection portion 6A are wound around the outer peripheral surface of the columnar portion 21A on both sides of the flange portion 22A. An arc portion 212A is formed at the entrance of the groove portion 211A so that each RE-based superconducting wire 100 does not bend smaller than the allowable bending diameter.

An insulating material 24 is arranged on the outer peripheral surface side of the two RE-based superconducting wires 100 in a wound state and is wound together with the two RE-based superconducting wires 100. As a result, the two RE-based superconducting wires 100 wound a plurality of times have a structure in which insulation is achieved for each turn and generation of induced current is suppressed.

Further, in the two RE-based superconducting wires 100, a bypass connecting portion 7A for connecting the superconducting conductor layers 3 to each other so as to be conductive with low resistance is formed in a portion other than the sintered connecting portion 6A. The bypass connecting portion 7A has a width equal to the entire width of the two RE superconducting wires 100 arranged with a gap (width equal to the width of the grooved frame member 20A) and a short RE superconducting wire 100B. Are connected over the outer peripheral surfaces of the two RE-based superconducting wires 100 by welding the surfaces with a brazing material made of a good conductor such as solder.
The RE-based superconducting wire 100B has the same layer structure as the RE-based superconducting wire 100.
Each of the two RE superconducting wire rods 100 is wound around the grooved frame member 20A with the superconducting conductor layer 3 facing outward with respect to the base material 1, and the RE superconducting wire rod 100B is The superconducting conductor layer 3 is connected to the base material 1 on the RE-based superconducting wire 100 side. As a result, the base material 1 is not present between the two superconducting conductor layers 3 of the RE-based superconducting wire 100 and the superconducting conductor layer 3 of the RE-based superconducting wire 100B, and the sintered connection portion 6A is in the normal conducting state. When the transition occurs, a bypass current flows from one RE-based superconducting wire 100 through the RE-based superconducting wire 100B to the other RE-based superconducting wire 100, so that burning-out of the sintered connection portion 6A can be prevented.

The extra length portions of the two RE-based superconducting wires 100 wound around the grooved frame member 20A may be fixed with a curable resin such as epoxy in order to maintain the wound state. Alternatively, it may be fixed by a C-shaped frame fitted to the outer circumference of the two wound RE-based superconducting wires 100.
The grooved frame member 20A may be fixed to the support plate 320 with an epoxy resin after the RE-based superconducting wire 100 is wound.

[Inductive winding frame material]
The non-inductive winding frame member 30 is the same as that described above. In this non-inductive winding frame material 30, the length of the extra length portion of the RE-based superconducting wire 100 pulled out from one double pancake coil 302 is longer than the length of the extra length portion of the other RE-based superconducting wire material 100. When the length becomes long, the difference is wound to protect the RE-based superconducting wire 100 from deformation and the like.
The extra length of the RE superconducting wire 100 wound around the non-inductive winding frame material 30 may be fixed with a curable resin such as epoxy or the like, or may be fixed with a C-shaped frame.
Further, the non-inductive winding frame member 30 may be fixed to the support plate 320 with an epoxy resin after winding the RE-based superconducting wire 100.

[Technical effects of connection structure]
The connecting structure 10A of the RE-based superconducting wire has the same technical effect as the connecting structure 10, and the grooved frame member 20A has two sintered parallel connection parts 6A of the RE-based superconducting wire 100. Can be protected by maintaining high mechanical strength in the groove portion 211A.
Further, in the grooved frame member 20A, since the two RE-based superconducting wires 100 are individually wound on both sides of the flange portion 22A by the columnar portion 21A, the two RE-based superconducting wires 100 are drawn out in parallel. It is possible to protect the extra length of the part from bending and bending.

Further, the connection structure 10A has the sintered connection portion 6A and the RE-based superconducting wire rod even when the RE-based superconducting wire rod 100 of the two double pancake coils 302 held side by side is sintered and connected like the superconducting coil unit 300. The extra length of 100 can be effectively protected.

Further, in the connection structure 10, the two RE-based superconducting wire rods 100 are sintered and connected by the bridge connection of the other RE-based superconducting wire rods 100A, so that the two RE-based superconducting wire rods 100 are disposed on the respective planes. Sintering is performed even when the two RE-based superconducting wires 100 are arranged parallel to each other in the width direction and apart from each other so that they cannot be closely contacted and connected in a facing state. It is possible.

1 Superconducting Film Forming Substrate 3 Oxide Superconducting Conductor Layer 4 Internal Protective Layer 5 External Protective Layer 6, 6A Sintered Connection (Connection)
7,7A Bypass connection part 10,10A Connection structure 20,20A Grooved frame material 21,21A Columnar shape part 22,22A Flange part 23 Filler 24 Insulation material 30 Non-inductive winding frame material 40 Superconducting coil 60 Persistent current switch 100 , 100A, 100B RE-based superconducting wire 110 Connector 200 Current system 211, 211A Groove 300 Superconducting coil unit 302 Double pancake coil

Claims (7)

A tape-shaped base material having a superconducting conductor layer formed on one surface,
In a connection structure of a RE-based superconducting wire comprising a protective layer covering the base material,
A connection portion in which the superconducting conductor layer exposed from the protective layer of the two superconducting wires is sintered and connected ,
A frame member with a groove having a groove portion to which the connecting portion is fixed ,
A non-inductive winding frame member around which the extra length of one of the superconducting wires is wound,
A superconducting wire connection structure, characterized in that The grooved frame material includes a columnar portion,
The superconducting wire connecting structure according to claim 1, wherein the two superconducting wires connected by the connecting portion are wound around the columnar portion. 3. The superconducting wire connecting structure according to claim 1, wherein the two superconducting wires are connected so as to be able to conduct at a portion other than the connecting portion. 3. The superconducting wire rod according to claim 2, wherein the two superconducting wire rods are connected so as to be able to conduct at a portion other than the connecting portion and wound around the grooved frame member. Construction. The connection structure of the superconducting wire according to claim 3 or 4, wherein the two superconducting wires are connected by a superconducting wire other than the two superconducting wires in a portion other than the connecting portion. .. The superconducting wire connection structure according to any one of claims 1 to 5, wherein the groove portion has a resin or a low melting point metal. The two superconducting wires,
The superconducting wire connecting structure according to any one of claims 1 to 6, wherein the superconducting wire is connected so that the longitudinal directions of the superconducting wires toward the connecting portion are the same.

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