JP5123604B2 - Superconducting coil - Google Patents

Description

  The present invention relates to a superconducting coil in which pancake-type coil bodies are laminated in the axial direction.

  In recent years, various devices have been developed as power application devices using superconducting wires. For example, a superconducting magnetic energy storage device (hereinafter abbreviated as SMES) has features such as higher energy storage efficiency and faster energy loading / unloading speed than other energy storage devices. The development is underway energetically. In addition, development of AC coils typified by transformers, superconducting rotating machines typified by electric motors and generators, current limiters using high-resistance wires during normal conduction, and the like are also under development.

When such a power application device uses a metal-based superconducting wire such as NbTi or Nb ₃ Sn, liquid helium is used as a coolant, and the wire is not cooled to an extremely low temperature of about 4.2K. Since the superconducting state cannot be obtained, the cooling cost is increased, which is a practical problem. On the other hand, when a Bi (bismuth) -based or Y (yttrium) -based oxide superconducting wire is used, the superconducting transition temperature of the wire is relatively high, and 77.3 K as a coolant for bringing the wire into a superconducting state. Since liquid nitrogen can be used, the cooling cost can be significantly reduced.

In addition, it is known that a metallic superconducting wire such as NbTi or Nb ₃ Sn immediately causes a normal conducting transition when a current exceeding a critical current flows and cannot maintain a superconducting state. Therefore, for example, when SMES is configured using such a metal-based superconducting wire, when a current exceeding the critical current flows through the wire, the wire immediately undergoes normal conduction transition, and the energy accumulated in the coil is released. End up. On the other hand, in the case of a Bi-based or Y-based oxide superconducting wire, a superconducting state is maintained without causing a normal-conducting transition within a current range called a magnetic flux flow region even when a current exceeding the critical current is passed. be able to. Therefore, applications utilizing the advantages of such oxide superconducting wires are expected.

  For example, a tape-shaped Y-based oxide superconducting wire has a superconducting characteristic with a tape width of about 10 mm, a critical current of about 100 to 300 A when cooled to 77.3 K with liquid nitrogen and an external magnetic field of 0 T. Is available, and can be used as, for example, a pancake-type coil body (pancake coil). This pancake coil is formed by concentrically winding a tape-shaped superconducting wire around a cylindrical winding frame, and external connection electrodes are attached to the starting end and the terminating end of the superconducting wire, respectively. Is configured.

  By the way, when the pancake coil using the tape-shaped oxide superconducting wire is applied to various power devices such as SMES and a transformer, further increase in current is required. Therefore, it is considered to increase the allowable current that can be flowed as a whole coil by assembling a plurality of superconducting wires in the thickness direction and assembling them and winding the aggregate around a winding frame. It is also considered to increase the allowable current by stacking a plurality of pancake coils in the axial direction.

  However, when a plurality of superconducting wires are made into conductors, a drift occurs due to the difference in the self-inductance of each wire and the mutual inductance between the wires due to the difference in the winding length of each wire. Current drift occurs in which current flows. Then, the critical current of the superconducting wire in which the largest current flows due to the drift current limits the current that can flow through the entire assembly, so the critical current of the assembly is the sum of the critical currents of the assembled superconducting wires. The problem of being far below occurs.

  In addition, when superconducting wires wound around each coil are connected by stacking pancake coils, the winding length of the wire increases, so the difference in inductance may become larger. The current drift becomes more prominent.

In order to eliminate such inconvenience, a technique is known in which dislocation segments T (see FIG. 9) for disposing the disposition positions of the wire material inside and outside at regular intervals in the length direction of the wire material are known in the assembly ( (See Patent Documents 1 and 2). This technique is applied to, for example, a superconducting coil or a superconducting cable of a large electric device coil such as a large transformer or a large motor.
JP 2001-148210 A JP 2005-19323 A

  However, when the dislocation segment as described above is provided in the aggregate of the wires, the wire material is distorted at the dislocation segment portion, so that there is a problem that the superconducting characteristics are deteriorated.

  The present invention has been made to solve the above-described problems, and provides a superconducting coil capable of increasing the critical current by suppressing the generation of a drift current while suppressing the deterioration of the superconducting characteristics. For the purpose.

  To achieve the above object, a superconducting coil according to claim 1 of the present invention includes a first coil body, a second coil body adjacent to the first coil body in the axial direction, and the first coil body. A superconducting coil comprising a first coil body and a connection means for electrically connecting the second coil body, wherein the first coil body and the second coil body are respectively connected to the connection means. A predetermined number of tape-shaped superconducting wires, and a winding frame for concentrically winding these superconducting wires in the thickness direction of the superconducting wires and in the overlapping order. The connecting means includes a predetermined number of electrode portions equal to the number of superconducting wires constituting the coil body, and when n is an arbitrary positive integer equal to or less than the number of superconducting wires, the first coil Superconductivity arranged nth from the outside in the radial direction of the body An end portion of the material and an end portion of the superconducting wire arranged nth from the radial inner side of the second coil body are aligned in the axial direction of the coil body, The superconducting wire material of the first coil body and the superconducting wire material of the second coil body, which are fixed in a conductive manner and sandwich the electrode portion, are wound around the winding frame in opposite directions. And

  In the superconducting coil according to claim 1, as described above, the end of the superconducting wire disposed nth from the radially outer side of the first coil body on the common electrode portion of the connecting means, and the second Since the end of the superconducting wire arranged nth from the inside in the radial direction of the coil body is fixed to each other, for example, two coil bodies including two sheet-like superconducting wires are connected to the connecting means. When electrically connected by, the end of the superconducting wire located outside the one coil body is electrically connected to the end of the superconducting wire located inside the other coil body via the electrode part, It is possible to electrically connect the end portion of the superconducting wire located inside one coil body to the end portion of the superconducting wire located outside the other coil body via an electrode portion different from the above electrode portion. it can. Here, when a plurality of superconducting wires are overlapped in the thickness direction and wound around the winding frame in the overlapping order, the winding length of the superconducting wires disposed on the radially outer side becomes longer, Although it is known that a difference occurs in the winding length of the superconducting wire, in the superconducting coil according to claim 1, the connection means causes a difference in the winding length of the superconducting wire generated in one coil body. The corresponding superconducting wires of the two coil bodies can be connected to each other so that the difference in winding length of the superconducting wires generated in the other coil body cancels each other. Therefore, as in the prior art, the electrodes were electrically connected by each electrode portion of the connecting means without providing a twisted portion (dislocation segment T in FIG. 9) at a predetermined location of the assembly in which superconducting wires were stacked in the thickness direction. The total winding length over the two coil bodies of the connection body composed of the superconducting wire of one coil body and the superconducting wire of the other coil body corresponding to this superconducting wire is made substantially equal for each connection body, and each connection Since it is possible to suppress the drift by making the difference in the self-inductance of the body difficult to occur, the critical current of the entire coil can be increased while sufficiently suppressing the deterioration of the superconducting characteristics.

  In the above description, the case where the coil bodies including two superconducting wires are electrically connected by the connecting means is described as an example. However, the coil bodies including three or more superconducting wires are electrically connected by the connecting means. Even in the case of connection, the electrodes of the connecting means are arranged first by the end portion of the superconducting wire arranged first from the outside in the radial direction of one coil body and first from the inside in the radial direction of the other coil body. The end of the superconducting wire is electrically connected to the end of the superconducting wire disposed second from the outside in the radial direction of one coil body and the second end from the inside in the radial direction of the other coil body. The end of the superconducting wire is arranged n-th from the outside in the radial direction of one coil body and the inside of the other coil body from the inside in the radial direction. And the end of the superconducting wire arranged second By electrically connecting, the difference in the winding length of the superconducting wire produced in one coil body and the difference in the winding length of the superconducting wire produced in the other coil body cancel each other, The total winding length over two coil bodies of the coupling body composed of the superconducting wire material of the coil body and the superconducting wire material of the other coil body corresponding to the superconducting wire material may be made substantially equal in each coupling body. It becomes possible.

  In the superconducting coil according to claim 1, preferably, the winding frames of the coil bodies have substantially the same outer diameter dimensions, and the superconducting wire is wound around the winding frame at a predetermined number of turns. (Claim 2). With this configuration, the winding length of the superconducting wire is shortened at equal intervals from the radially outer superconducting wire to the radially inner superconducting wire, and nth from the radially outer side of each coil body. Since the superconducting wire can be wound around the winding frame so that the winding lengths of the superconducting wires to be arranged are substantially equal to each other, it can easily correspond to the superconducting wire of the first coil body and this superconducting wire. The total winding length over the two coil bodies of the connected body composed of the superconducting wire of the second coil body can be made substantially equal for each connected body.

  In the superconducting coil according to claim 1 or 2, preferably, the predetermined number of electrode portions are arranged along the winding direction of the superconducting wire, and each extend in the axial direction of the coil body. The superconducting wire is extended to a position over the end of the superconducting wire, the end of which is arranged more radially inward, in the winding direction. It is connected to the electrode part at a position (Claim 3). In this configuration, for example, when two coil bodies including three superconducting wires are electrically connected by the connecting means, the ends of the superconducting wires outside the one coil body and the superconducting wires inside the other coil body are connected. If the end portion is connected in the axial direction of the coil body by the electrode portion arranged at a predetermined position, the end portion of the superconducting wire intermediate in one coil body and the end portion of the superconducting wire intermediate in the other coil body are connected. , Connected in the axial direction of the coil body by another electrode portion arranged at a position shifted in the winding direction of the superconducting wire from the predetermined position, the end of the superconducting wire inside one coil body and the other coil body Each coil body can be connected to the end of the outer superconducting wire in the axial direction of the coil body by a further electrode portion disposed at a position further shifted from the predetermined position in the winding direction of the superconducting wire. Of superconducting wires in Japan While maintaining the mechanisms can be the ends of the superconducting wire connected by the respective electrode portions. Thereby, unlike the case where superconducting wires of the same coil body are connected to each electrode part while intersecting in the radial direction of the coil body, it is possible to prevent the connection configuration by the connecting means from becoming complicated.

  In the superconducting coil according to claim 3, preferably, the end of the superconducting wire of the first coil body and the end of the superconducting wire of the second coil body corresponding to the superconducting wire are It is connected to the same surface of the electrode part (Claim 4). If comprised in this way, since the radial thickness of the connection location which consists of a pair of superconducting wire and an electrode part can be made small, the enlargement of the said superconducting coil can be suppressed.

  In the superconducting coil according to claim 4, preferably, the electrode portion is an electrode portion connected to an end portion on a radially inner side of the superconducting wire, and a connection surface with the superconducting wire is the winding frame. Is embedded in the winding frame so as to be substantially flush with the outer peripheral surface of the first embodiment (Claim 5). If comprised in this way, since it can connect to an electrode part in a physically smooth mode, without distorting the end part of the diameter direction inner side of a superconducting wire, superconducting characteristic of the superconducting characteristic resulting from distortion of the shape of a superconducting wire The decrease can be suppressed.

  In the superconducting coil according to any one of claims 3 to 5, preferably, the adjacent electrode portions are connected via an insulating member (claim 2). If comprised in this way, a connection means can be made into a single unit body easily.

  The superconducting coil according to any one of claims 1 to 6, further comprising a tape-like support body that is disposed along the superconducting wire and is wound around the winding frame together with the superconducting wire. (Claim 5). If comprised in this way, since the electromagnetic stress applied in a high magnetic field can be disperse | distributed to a support body, the electromagnetic stress which acts on a superconducting wire can be reduced. Thereby, the fall of a critical current density can be suppressed.

  According to the superconducting coil of the present invention, the connection means causes the difference in the winding length of the superconducting wire generated in one coil body and the difference in the winding length of the superconducting wire generated in the other coil body to each other. Since the superconducting wires corresponding to the two coil bodies can be connected to each other so as to cancel each other out, a twisted portion is not provided at a predetermined position of the assembly in which the superconducting wires are stacked in the thickness direction as in the prior art. A total winding spanning two coil bodies of a connected body composed of a superconducting wire of one coil body electrically connected by each electrode portion of the connecting means and a superconducting wire of the other coil body corresponding to the superconducting wire. It is possible to suppress the drift by making the lengths substantially equal in each connecting body and making it difficult for a difference to occur in the self-inductance of each connecting body. Thereby, the critical current of the whole coil can be increased while sufficiently suppressing the deterioration of the superconducting characteristics.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing the overall configuration of a superconducting coil according to an embodiment of the present invention, and FIG. 2 is a perspective view for explaining the configuration of a collective conductor of the superconducting coil. 3 and 4 are cross-sectional views of the superconducting coil shown in FIG. 1, and FIG. 5 is a front view showing the main configuration of the electrode unit of the superconducting coil. First, with reference to FIG. 1, the whole structure of the superconducting coil 1 by one Embodiment of this invention is demonstrated.

  As shown in FIG. 1, the superconducting coil 1 of this embodiment includes an upper coil body (first coil body) 1A and a lower coil body (second coil) adjacent to the lower side in the axial direction of the upper coil body 1A. Body) 1B. Specifically, the winding frame 2 common to both the coil bodies 1A and 1B, the collective conductor 3A for the upper coil body 1A concentrically wound around the upper half portion of the winding frame 2, and the winding frame 2 And a collective conductor 3 </ b> B for the lower coil body 1 </ b> B wound concentrically around the lower half portion. In the present embodiment, the upper coil body 1A is a so-called single pancake type coil body (hereinafter referred to as “single pan cake”) formed by winding the collective conductor 3A on the upper part of the winding frame 2 so as to form one stage. The lower coil body 1B is also a single pancake coil formed by winding the collective conductor 3B around the winding frame 2 in a single stage. The superconducting coil 1 may be formed by laminating individually configured upper and lower coil bodies in the axial direction. In this case, the upper coil body and the lower coil body are each provided with an individual winding frame, but the winding frames of each coil body are preferably formed to have the same outer diameter.

  The superconducting coil 1 electrically connects the outer electrode 4 connected to the collective conductor 3A of the upper coil body 1A, the outer electrode 5 connected to the collective conductor 3B of the lower coil body 1B, and the collective conductor 3A and the collective conductor 3B. And an electrode unit (connecting means) 6 to be connected.

  As shown in FIG. 2, the assembly conductor 3A is composed of a predetermined number (two in the present embodiment) of tape-like superconducting wires 31 and 32, and these superconducting wires 31, 32 are stacked in the thickness direction. In the state and in the overlapped order, it is configured by being wound a predetermined number of times concentrically around the upper part of the winding frame 2. In the winding state of the assembly conductor 3A, the superconducting wire 31 is located on the radially outer side of the upper coil body 1A, and the superconducting wire 32 is located on the radially inner side.

  The collective conductor 3B is composed of the same number (two) of tape-like superconducting wires 33 and 34 as the collective conductor 3A, and the superconducting wires 33, 34 are stacked in the thickness direction, and In this overlapping order, the winding conductors 2 are concentrically wound around the lower portion of the winding frame 2 to be wound a number of times equal to the number of windings of the collective conductor 3A. And in the winding state of the assembly conductor 3B, the superconducting wire 33 is located on the radially outer side of the lower coil body 1B, and the superconducting wire 34 is located on the radially inner side.

  Further, in the present embodiment, the collective conductor 3A is wound counterclockwise in a top view from the inside in the radial direction of the winding frame 2 to the outside, whereas the collective conductor 3B is in the radial direction of the winding frame 2 The coil is wound clockwise from the inside to the outside in a top view, and the winding direction of the superconducting wire is reversed in the coil bodies 1A and 1B.

  The superconducting wires 31 to 34 are wire layers composed of a plurality of layers, for example, an insulating layer made of a metal oxide, a superconducting layer (Y-based superconducting layer), and an electrode joint on a metal base material such as Hastelloy. The metal layers for use are laminated in this order.

  As described above, each of the superconducting wires 31 to 34 is wound from the inside in the radial direction of the winding frame 2 to the outside, and joined to the electrode unit 6 (soldering) at the start end portions 31a to 34a that are the winding start end portions. A portion to be wound around the winding frame 2, and a portion to be joined to the outer electrodes 4 and 5 at the end portions 31b to 34b which are the end portions of the winding in this order.

In this embodiment, an example in which Y (yttrium) -based oxide superconducting wires 31 to 34 (hereinafter simply referred to as superconducting wires 31 to 34) are described as the superconducting wires 31 to 34. However, the present invention is not limited thereto, and Bi (bismuth) -based oxide superconducting wires using Ag and an Ag-based alloy sheath may be used. Further, it may be a superconducting wire 31 to 34 including the _Nb 3 Al or MgB _2.

  The winding frame 2 includes a cylindrical body portion 21 around which the collective conductors 3A and 3B are wound, and an extending direction of the body portion 21 from the upper end portion, the central portion, and the lower end portion in the axial direction of the body portion 21 in a substantially orthogonal direction. Each has an upper flange portion 22, an intermediate flange portion 23, and a lower flange portion 24 that extend.

  Each of the flange portions 22 to 24 is a flat disk member provided on the trunk portion 21. In a state where these flange portions 22 to 24 are assembled to the body portion 21, the inner peripheral surface of each flange portion 22 to 24 and the outer peripheral surface 21 a of the body portion 21 are bonded together with an adhesive or the like, and the flange portion 22. Each flange part 22-24 and the trunk | drum 21 are connected by ~ 24 being fastened with the volt | bolt which is not illustrated. The trunk portion 21 and the flange portions 22 to 24 may be integrally formed.

  Further, notches 22a and 22b for attaching the outer electrodes 4 and 5 are formed on the radially outer side of the upper flange portion 22, and the outer electrodes 4 and 5 are disposed on the radially outer side of the middle flange portion 23. Incisions 23a and 23b for attaching the are formed. Further, a cutout portion 24 a for attaching the outer electrode 5 is formed on the radially outer side of the lower flange portion 24. These notches 22a, 22b, 23a, 23b, and 24a have a notch width through which the outer electrodes 4 and 5 can be inserted, and a part of the flanges 22 to 24 is part of the outer periphery of each flange 22 to 24. It is formed by cutting a predetermined length from the surface. In a state where these flange portions 22 to 24 are assembled to the body portion 21, the cut portions 22 a, 23 a and 24 a face each other in the axial direction of the superconducting coil 1, and the cut portions 22 b and 23 b are formed in the superconducting coil 1. It faces to the axial direction.

  The outer electrodes 4 and 5 are substantially flat external connection electrodes. The outer electrode 4 is an electrode on the input side, and is fixed by an adhesive or the like in a state of being inserted into the cut portions 22b and 23b of the flange portions 22 and 23. The outer electrode 5 is an output-side electrode, and is fixed by an adhesive or the like in a state where it is inserted into the notches 22a, 23a and 24a of the flange portions 22, 23 and 24. The outer electrodes 4 and 5 have surfaces (outer surfaces 4a and 5a) facing radially outward, the outer surface 4a and the superconducting wires 31 and 32 are joined by soldering, and the outer surface 5a and the superconducting wires 33 and 34 is joined by soldering.

  Hereinafter, a specific configuration of the outer electrodes 4 and 5 will be described.

  As shown in FIG. 3, the outer electrode 4 includes an electrode body 41 joined to the superconducting wires 31 and 32, and a current lead 42 extending from the electrode body 41 to the upper side in the axial direction of the superconducting coil 1. The electrode body 41 is electrically connected to the terminal portion 31 b of the superconducting wire 31 via the solder 46 and electrically connected to the terminal portion 32 b of the superconducting wire 32 via the solder 46. A second copper electrode 44, and an insulating material 45 disposed between the first copper electrode 43 and the second copper electrode 44 and having an insulating function with respect to both the electrodes 43, 44.

  As shown in FIG. 4, the outer electrode 5 includes an electrode body 51 joined to the superconducting wires 33 and 34, and a current lead 52 extending from the electrode body 51 to the upper side in the axial direction of the superconducting coil 1. Yes. The electrode body 51 is electrically connected to the terminal portion 33 b of the superconducting wire 33 via the solder 56 and electrically connected to the terminal portion 34 b of the superconducting wire 34 via the solder 56. A second copper electrode 54 and an insulating material 55 disposed between the first copper electrode 53 and the second copper electrode 54 and having an insulating function with respect to both the electrodes 53, 54.

  The outer surfaces 4a and 5a of the outer electrodes 4 and 5 are inclined at a predetermined taper angle in the winding direction of the superconducting wires 31 to 34 with respect to the inner surfaces of the outer electrodes 4 and 5. The taper angle can be arbitrarily set, but is preferably about 15 ° or less. By providing the outer surfaces 4a and 5a having such a small taper angle, the superconducting wires 31 to 34 can be wound without giving a local flatwise distortion, so that the critical current is not lowered. Superconducting wires 31 to 34 can be joined to the corresponding outer electrodes 4 and 5.

  Here, in this embodiment, the electrode unit 6 is provided in the outer peripheral surface 21a of the trunk | drum 21, as shown in FIG. The electrode unit 6 has an axial length substantially equal to the axial length of the barrel portion 21 so as to be disposed over substantially the entire axial direction of the barrel portion 21 and is formed in a substantially semicircular shape in cross section. ing. The convex outer surface 6 a of the electrode unit 6 is a surface joined to the superconducting wires 31 to 34 by soldering, and has a shape along the outer peripheral surface 21 a of the body portion 21. The electrode unit 6 is embedded in the outer peripheral surface 21a of the body portion 21 with the outer surface 6a of the electrode unit 6 facing outward in the radial direction and the outer surface 6a exposed to the outer side in the radial direction. The outer side surface 6 a forms a part of the outer peripheral surface 21 a of the body portion 21. Therefore, the outer peripheral surface 21a of the winding frame 2 and the outer surface 6a of the electrode unit 6 are continuously connected at the boundary portion, and in the state where the superconducting wires 31 to 34 are connected to the electrode unit 6, the superconducting wires 31 to 31 are connected. 34 can be prevented from being bent and distorted.

  Hereinafter, the configuration of the electrode unit 6 will be specifically described.

  As shown in FIG. 5, the electrode unit 6 includes a first electrode portion 61 and a second electrode portion 62 arranged along the winding direction of the superconducting wires 31 to 34, and is disposed between these electrode portions 61 and 62. And an insulating material (insulating member) 63 having an insulating function with respect to both electrode portions 61 and 62. The first electrode portion 61 is provided across the coil bodies 1A and 1B in such a manner as to extend in the axial direction of the superconducting coil 1, and the starting end portion 31a of the superconducting wire 31 is soldered to the upper portion thereof (see FIG. 3). The start end portion 34a of the superconducting wire 34 is fixed to the lower portion thereof through a solder 64 (see FIG. 4). Further, the second electrode portion 62 is provided across the coil bodies 1A and 1B in such a manner as to extend in the axial direction of the superconducting coil 1, and the start end portion 32a of the superconducting wire 32 is soldered to the upper portion thereof (see FIG. 3). ), And a starting end portion 33a of the superconducting wire 33 is fixed to the lower portion thereof through a solder 64 (see FIG. 4).

  That is, as shown in FIG. 5, the superconducting wire 31 has a start end portion 31 a of the superconducting wire 32 in which the start end portion 31 a is arranged on the radially inner side in a direction opposite to the winding direction (a clockwise direction in a top view). And is connected to the first electrode portion 61 at the position. The superconducting wire 33 extends to a position where the starting end portion 33a of the superconducting wire 34, which is arranged on the inner side in the radial direction, rides over the direction opposite to the winding direction (counterclockwise direction when viewed from above). In addition, it is connected to the second electrode portion 62 at this position. Accordingly, the superconducting wires 31 and 32 of the upper coil body 1A sandwiching the electrode portions 61 and 62 and the superconducting wires 33 and 34 of the lower coil body 1B are wound around the winding frame 2 in opposite directions. In FIG. 5, for the convenience of illustration, the superconducting wires 31 and 32 or the superconducting wires 33 and 34 are shown shifted in the axial direction.

  Thereby, the first end 31a of the superconducting wire 31 outside the collective conductor 3A and the start end 34a of the superconducting wire 34 inside the collective conductor 3B are aligned in the axial direction of the superconducting coil 1 and The starting end portion 32a of the superconducting wire 32 inside the collective conductor 3A and the starting end portion 33a of the superconducting wire 33 outside the collective conductor 3B are electrically connected via one electrode portion 61, and the axial direction of the superconducting coil 1 Are electrically connected via the second electrode portion 62 of the electrode unit 6. Here, in general, when a plurality of superconducting wires are stacked in the thickness direction and wound around the winding frame in the stacked order, the winding length of the superconducting wires disposed on the radially outer side becomes longer. It is known that there is a difference in the winding length of each superconducting wire. In this embodiment, “the winding length of the superconducting wire 31”> “the winding length of the superconducting wire 32”, “the superconducting wire”. The winding length of 33 ”>“ the winding length of superconducting wire 34 ”. The difference between the winding lengths of superconducting wires 31 and 32 generated in upper coil body 1A by electrode unit 6 is as follows. The superconducting wires 31 and 34 of the two coil bodies 1A and 1B are connected so that the difference in winding length of the superconducting wires 33 and 34 generated in the lower coil body 1B cancels each other, and the superconducting wires 32 and 33 is connected, so the first electrode unit 6 Two coil bodies 1A, which are a coupling body composed of superconducting wires 31 and 34 electrically connected by the pole part 61 and a coupling body composed of superconducting wires 32 and 33 electrically connected by the second electrode part 62, The total winding length over 1B is substantially equal.

  In the superconducting coil 1 configured as described above, electricity supplied to the upper coil body 1A through the outer electrode 4 causes the superconducting wires 31 and 32 of the assembly conductor 3A to be watched from the radially outer side to the inner side in a top view. It flows in the rotating direction, flows through the electrode portions 61 and 62 of the electrode unit 6 provided on the outer peripheral surface 21a of the winding frame 2 and flows from the upper coil body 1A to the lower coil body 1B, and each superconducting wire 34 corresponding to the collective conductor 3B. , 33 flow in the clockwise direction from the inside in the radial direction to the outside in the top view. And the total winding length over two coil bodies 1A and 1B of the connection body which consists of the superconducting wire materials 31 and 34 which are the two electric current paths in the said superconducting coil 1, and the connection body which consists of the superconducting wire materials 32 and 33. , Are substantially equal as described above.

  Next, an example of a manufacturing procedure of the superconducting coil 1 having the above-described configuration is shown below. First, the electrode unit 6 is attached to the outer peripheral surface 21 a of the body portion 21 in the winding frame 2. Specifically, after the upper flange portion 22 is fixed to the upper end portion of the body portion 21 with an adhesive or the like, the outer surface 6a of the electrode unit 6 is along the outer peripheral surface 21a of the winding frame 2 and the outer periphery of the body portion 21 is fixed. The electrode unit 6 is fixed to the surface 21a.

  Next, the superconducting wires 31 and 32 are joined to the outer surface 6a of the electrode unit 6, respectively. Specifically, the upper part of the first electrode part 61 of the electrode unit 6 and the starting end part 31a of the superconducting wire 31 are joined by soldering, and the upper part of the second electrode part 62 of the electrode unit 6 and the starting end of the superconducting wire 32 are joined. The part 32a is joined by soldering. And after fixing the intermediate | middle stage flange part 23 to the axial direction center part of the trunk | drum 21 with an adhesive agent etc., it superimposes the superconducting wire 31 and 32 in the thickness direction so that the superconducting wire 31 may be located on the radial direction outer side, The outer circumferential surface 21a is wound a plurality of times concentrically counterclockwise from the radially inner side to the outer side as viewed from above in the overlapping order.

  Next, the superconducting wires 31 and 32 and the outer electrode 4 are joined. That is, the outer electrode 4 is inserted into the notches 22b and 23b of the flange portions 22 and 23 of the winding frame 2, and the terminal portions 31b and 32b of the superconducting wires 31 and 32 and the outer surface 4a of the outer electrode 4 are joined by soldering. To do. Specifically, the first electrode 43 of the outer electrode 4 and the end portion 31b of the superconducting wire 31 are joined by soldering, and the second electrode 44 of the outer electrode 4 and the end portion 32b of the superconducting wire 32 are soldered. Join by.

  Next, superconducting wires 33 and 34 are joined to the outer surface 6a of the electrode unit 6, respectively. Specifically, the lower part of the first electrode part 61 of the electrode unit 6 and the starting end part 34a of the superconducting wire 34 are joined by soldering, and the lower part of the second electrode part 62 of the electrode unit 6 and the starting end of the superconducting wire 33 are joined. The part 33a is joined by soldering. And after fixing the lower stage flange part 24 to the lower end part of the trunk | drum 21 with an adhesive agent etc., the superconducting wire 33,34 was piled up in the thickness direction so that the superconducting wire 33 might be located on the radial direction outer side, and the piled up As in the order, the outer peripheral surface 21a is concentrically wound from the inside in the radial direction to the outside in the clockwise direction as viewed from the top, the same number of times as the number of turns of the superconducting wires 31 and 32.

  Next, the superconducting wires 33 and 34 and the outer electrode 5 are joined. That is, the outer electrode 5 is inserted into the cut portions 22a to 24a of the flange portions 22 to 24 of the winding frame 2, and the terminal portions 33b and 34b of the superconducting wires 33 and 34 and the outer surface 5a of the outer electrode 5 are joined by soldering. To do. Specifically, the first electrode 53 of the outer electrode 5 and the end portion 34b of the superconducting wire 34 are joined by soldering, and the second electrode 54 of the outer electrode 5 and the end portion 33b of the superconducting wire 33 are soldered. Join by. Thereby, the assembly of the superconducting coil 1 of this embodiment is completed.

  In the superconducting coil 1 of the present embodiment, the first end portion 31a of the superconducting wire 31 disposed on the first electrode portion 61 of the electrode unit 6 from the outer side in the radial direction of the upper coil body 1A (that is, radially outer side), The superconducting wire 34 arranged first from the radial inner side of the lower coil body 1B (that is, the radial inner side) is fixed to the start end portion 34a so as to be conductive, and is connected to the second electrode portion 62 of the electrode unit 6 on the upper side. The superconducting wire 32 is disposed second from the radially outer side of the coil body 1A (that is, radially inner side) and the second end from the radially inner side of the lower coil body 1B (that is, radially outer side). Since the start end portion 33a of the superconducting wire 33 is fixed to be conductive, the difference in winding length between the superconducting wires 31 and 32 generated in the upper coil body 1A and the superconducting power generated in the lower coil body 1B. The superconducting wires 31 and 34 of the two coil bodies 1A and 1B are electrically connected and the superconducting wires 32 and 33 are electrically connected so that the difference in winding length between the wires 33 and 34 cancels each other. can do. Thus, unlike the conventional case, the first electrode portion 61 of the electrode unit 6 can be electrically connected without providing a twisted portion (the dislocation segment T in FIG. 9) at a predetermined position of the assembly in which superconducting wires are stacked in the thickness direction. A total number of windings over the two coil bodies 1A and 1B of the connecting body composed of the superconducting wires 31 and 34 connected to each other and the connecting body composed of the superconducting wires 32 and 33 electrically connected by the second electrode part 62. By making the lengths substantially equal and making it difficult for differences to occur in the self-inductance of each coupling body, it is possible to suppress the current drift, so that the critical current of the superconducting coil 1 is increased while sufficiently suppressing the deterioration of the superconducting characteristics. be able to.

  Further, since the number of turns of the assembly conductor 3A around the winding frame 2 and the number of turns of the assembly conductor 3B around the winding frame 2 are made equal, the superconducting wires 31 disposed on the radially outer sides of the coil bodies 1A, 1B, The superconducting wires 31 to 34 are attached to the reel 2 so that the winding lengths of the 33 are substantially equal to each other and the winding lengths of the superconducting wires 32 and 34 disposed radially inward are substantially equal to each other. Since it can be wound, the total winding length over the two coil bodies 1A and 1B of the coupling body made of the superconducting wires 31 and 34 and the two coil bodies of the coupling body made of the superconducting wires 32 and 33 can be easily performed. The total winding length over 1A and 1B can be made substantially equal.

  Moreover, the electrode parts 61 and 62 provided over two coil bodies 1A and 1B in the aspect extended in the axial direction of the superconducting coil 1 are arranged along the winding direction of the superconducting wires 31 to 34, and the superconducting wire 31 ( 33) is extended to a position where the start end portion 31a (33a) extends over the start end portion 32a (34a) of the superconducting wire 32 (34) arranged on the radially inner side in the winding direction, and the electrode at the position By connecting to the part 61 (62), the overlapping ends of the superconducting wires 31 to 34 in the coil bodies 1A and 1B are maintained, and the start end parts 31a to 34a of the superconducting wires 31 to 34 are connected to the electrode parts 61 and 62, respectively. Can be connected. Thus, unlike the case where the superconducting wires 31 and 32 (33 and 34) of the same coil body 1A (1B) are connected to the electrode portions 61 and 62 while intersecting the radial direction of the coil bodies 1A and 1B, the electrodes It is possible to prevent the connection configuration by the unit 6 from becoming complicated.

  Further, the starting end portion 31a (32a) of the superconducting wire 31 (32) of the upper coil body 1A and the starting end portion 34a (33a) of the superconducting wire 34 (33) of the lower coil body 1B are connected to the electrode portion 61 (62). By connecting to the same surface, the thickness in the radial direction of the connecting portion composed of the pair of superconducting wires 31, 34 (32, 33) and the electrode portion 61 (62) can be reduced. Can be suppressed.

  Further, the electrode unit 6 is embedded in the body portion 21 of the winding frame 2 so that the outer surface 6 a that is a connection surface with the superconducting wires 31 to 34 is substantially flush with the outer peripheral surface 21 a of the winding frame 2. By configuring, it is possible to connect the starting end portions 31a to 34a on the radially inner side of the superconducting wires 31 to 34 to the electrode unit 6 in a physically smooth manner without distorting the shape, so that the shapes of the superconducting wires 31 to 34 are configured. It is possible to suppress a decrease in superconducting characteristics due to the distortion of the.

  Moreover, since the electrode parts 61 and 62 are arranged along the winding direction of the superconducting wires 31 to 34 and are connected via the insulating material 63, the electrode unit 6 is easily formed as a single unit body. Can do.

  Note that the above-described effects can be easily obtained also in a superconducting coil configured by laminating superconducting coils 1 of the present embodiment including the upper coil body 1A and the lower coil body 1B in the axial direction.

  The superconducting coil 1 of the present invention is not limited to the above embodiment.

  For example, the assembly conductors 3A and 3B may further include a tape-like support body that is disposed along the superconducting wires 31 to 34 and is wound around the winding frame 2 together with the superconducting wires 31 to 34. When such assembly conductors 3A and 3B are used, the electromagnetic stress applied in a high magnetic field can be dispersed in the support, so that the electromagnetic stress acting on the superconducting wires 31 to 34 can be reduced. Become. As a result, it is possible to suppress a decrease in critical current density.

  In the above embodiment, the present invention has been described with reference to an example in which the present invention is applied to the superconducting coil 1 formed by laminating the upper coil body 1A and the lower coil body 1B, which are so-called single pancake coils, in the axial direction. The present invention is not limited to this, and can also be applied to a superconducting coil formed by stacking so-called double pancake type coil bodies (hereinafter referred to as “double pancake coils”) in the axial direction. The double pancake coil is a central portion of the assembly conductor made of a plurality of superconducting wires in the length direction to one end, and the central portion is used as a winding start portion on the radially inner side, and the upper portion in the axial direction of the winding frame. For example, while concentrically winding from the inside in the radial direction to the outside in a top view in the clockwise direction, the central portion of the collective conductor from the other end to the other end, the central portion as the winding start portion on the inside in the radial direction, the axial direction of the reel For example, in the double pancake coil, the inner and outer positions (overlapping order) of the superconducting wires are arranged vertically in the lower pancake coil. In two stages, it corresponds.

  FIG. 6 is a perspective view showing an overall configuration of a superconducting coil according to a modification of the present embodiment, and FIGS. 7 and 8 are a sectional view and a front view of the electrode unit of the superconducting coil shown in FIG. Hereinafter, the configuration of the superconducting coil 101 according to a modification of the present embodiment will be described.

  As shown in FIG. 6, a superconducting coil 101 according to this modification includes an upper coil body (first coil body) 101A and a lower coil body (second coil) adjacent to the lower side in the axial direction of the upper coil body 101A. Body) 101B. Specifically, the winding frame 102 common to both the coil bodies 101A and 101B, and the collective conductor 103A for the upper coil body 101A that is wound around the upper half portion of the winding frame 102 so as to be vertically arranged in two stages, An assembly conductor 103B for the lower coil body 101B is provided around the lower half portion of the winding frame 102 so as to be wound in two upper and lower stages. In this embodiment, the upper coil body 101A is a double pancake coil configured by winding the collective conductor 103A on the upper part of the winding frame 102 in two upper and lower stages, and the lower coil body 101B is also wound. This is a double pancake coil formed by winding the collective conductor 103 </ b> B at the lower part of the frame 102 so as to be two steps up and down.

  The assembly conductor 103A is composed of a predetermined number (three in this modification) of tape-shaped superconducting wires 131, 132, 133, and these superconducting wires 131-133 are stacked in the thickness direction, and It is configured by being wound a predetermined number of times in two upper and lower stages on the upper part of the reel 102 in the stacked order. In other words, the upper stage of the collective conductor 103A is wound clockwise from the radial inner side to the outer side of the winding frame 102 as viewed from above, and the lower stage of the collective conductor 103A is viewed from the upper side from the radial inner side to the outer side of the winding frame 102. Is wound counterclockwise. Further, the upper stage of the collective conductor 103B is wound clockwise from the radial inner side to the outer side of the winding frame 102 in a top view, and the lower stage of the collective conductor 103B is viewed from the upper side to the outer side in the radial direction of the winding frame 102. Is wound counterclockwise. And in the winding state of the assembly conductor 103A, the superconducting wire 131 is located on the radially outer side of the upper coil body 101A across the upper and lower two stages, and the superconducting wire 132 is located in the middle in the radial direction across the upper and lower two stages, The superconducting wire 133 is located radially inward over the upper and lower two stages.

  The assembly conductor 103B is composed of the same number (three) of tape-shaped superconducting wires 134, 135, and 136 (see FIG. 8) as the assembly conductor 103A, and these superconducting wires 134 to 136 are arranged in the thickness direction. In the overlapped state and in the overlapping order, the winding conductor 102 is concentrically wound around the lower portion of the winding frame 102 to be wound the same number of times as the number of turns of the collective conductor 103A. And in the winding state of the assembly conductor 103B, the superconducting wire 134 is positioned radially outside the lower coil body 1B across the two upper and lower stages, and the superconducting wire 135 is positioned radially in the middle along the two upper and lower stages, Superconducting wire 136 is located radially inward over the upper and lower two stages.

  Further, outer electrodes 104 and 105 for external connection are respectively provided at the upper end of winding of the collective conductor 103A of the upper coil body 101A and the lower end of winding of the collective conductor 103B of the lower coil body 101B. It is connected. Since the configuration of these outer electrodes 104 and 105 is basically the same as that of the outer electrodes 4 and 5 except that the number of copper electrodes to be joined to the superconducting wire is three, detailed description thereof is omitted. . The outer surfaces of the outer electrodes 104 and 105 are configured to have a taper angle of about 15 ° or less in the winding direction with respect to the inner surfaces.

  The superconducting coil 101 is an electrode unit that electrically connects the lower winding end of the collective conductor 103A of the upper coil body 101A and the upper winding end of the collective conductor 103B of the lower coil body 101B. (Connecting means) 106 is provided. As shown in FIGS. 7 and 8, the electrode unit 106 includes a first electrode part 161, a second electrode part 162, and a third electrode part 163 arranged along the winding direction of the superconducting wires 131 to 136, It is comprised by the two insulating materials (insulating member) 164 each arrange | positioned between the electrode parts 161 and 162 and between the electrodes 162 and 163. The first electrode portion 161 is provided across the coil bodies 101A and 101B in such a manner as to extend in the axial direction of the superconducting coil 101, and an end portion of the superconducting wire 131 is placed on the upper portion thereof via solder 165 (see FIG. 7). In addition, the end of the superconducting wire 136 is fixed to the lower portion thereof so as to be conductive through unillustrated solder. The second electrode portion 162 is provided across the coil bodies 101A and 101B in such a manner as to extend in the axial direction of the superconducting coil 101, and the end portion of the superconducting wire 132 can be conducted through the solder 165 at the upper portion thereof. In addition, the end portion of the superconducting wire 135 is fixed to the lower portion of the superconducting wire 135 through a solder (not shown) so as to be conductive. The third electrode portion 163 is provided across the coil bodies 101A and 101B in such a manner as to extend in the axial direction of the superconducting coil 101, and the end portion of the superconducting wire 133 can be conducted through the solder 165 thereon. In addition, the end portion of the superconducting wire 134 is fixed to the lower portion thereof so as to be conductive through solder (not shown).

  That is, the superconducting wire 132 extends to a position where the end of the superconducting wire 133 gets over the end of the superconducting wire 133 in the lower winding direction (counterclockwise direction when viewed from above) of the collective conductor 103A. Is extended to a position where the end of the superconducting wire 132 further extends in the winding direction, and is connected to the corresponding electrode portions 161 and 162 at each position. Further, the superconducting wire 135 is extended to a position where the end of the superconducting wire 136 gets over the end of the superconducting wire 136 in the upper winding direction of the assembly conductor 103B (clockwise as viewed from above). The end portion of the superconducting wire 135 is extended to a position that further crosses the end portion of the superconducting wire 135 in the winding direction, and is connected to the corresponding electrode portions 163 and 162 at the respective positions. Therefore, also in the superconducting coil 101 including the double pancake type coil bodies 101A and 101B according to this modification, the lower part of the superconducting wires 131 to 133 of the upper coil body 101A sandwiching the electrode parts 161 to 163, and the lower coil The superconducting wires 134 to 136 of the body 101B are wound around the winding frame 102 in opposite directions. As shown in FIG. 7, the outer surface of the electrode unit 106 is configured to have a taper angle of about 15 ° or less on both sides with the central portion in the winding direction of the electrode portion 162 as a vertex. It is difficult for the flat-wise distortion to occur locally at 136.

  Thus, the first electrode of the electrode unit 106 in a state where the end of the superconducting wire 131 outside the assembly conductor 103A and the end of the superconducting wire 136 inside the assembly conductor 103B are aligned in the axial direction of the superconducting coil 101. A state in which the end of the superconducting wire 162 in the middle of the assembly conductor 103A and the end of the superconducting wire 135 in the middle of the assembly conductor 103B are aligned in the axial direction of the superconducting coil 101. The end of the superconducting wire 133 inside the collective conductor 103A and the end of the superconducting wire 134 outside the collective conductor 103B are electrically connected via the second electrode part 132 of the electrode unit 106. The electrodes 101 are electrically connected via the third electrode portion 163 of the electrode unit 6 while being arranged in the axial direction.

  The electrode unit 106 causes a difference in winding length between the superconducting wires 131 to 133 generated in the upper coil body 101A and a difference in winding length between the superconducting wires 134 to 136 generated in the lower coil body 101B. Since the superconducting wires 131 and 136 of the two coil bodies 101A and 101B are connected, the superconducting wires 132 and 135 are connected, and the superconducting wires 133 and 134 are connected so as to cancel each other, the first electrode portion 161 of the electrode unit 106 is connected. Electrically connected by the superconducting wires 131 and 136 electrically connected by the second electrode portion 162, electrically connected by the second electrode portion 162 and electrically connected by the third electrode portion 163. It extends over the two coil bodies 101A and 101B of the connected body composed of the connected superconducting wires 133 and 134. Winding length are substantially equal.

  In this modification, the end portion of the superconducting wire 131 disposed on the first electrode portion 161 of the electrode unit 106 from the outer side in the radial direction of the upper coil body 101A (that is, the outer side in the radial direction) and the lower coil body 101B The superconducting wire 136 arranged first from the radial inner side (that is, the radial inner side) is fixed to the end of the superconducting wire 136 so as to be conductive, and the second coil 162 of the electrode unit 106 is radially connected to the upper coil body 101A The end of the superconducting wire 132 arranged second from the outside (that is, the middle in the radial direction), and the end of the superconducting wire 135 arranged second from the inside in the radial direction of the lower coil body 101B (ie, the middle in the radial direction) Are fixed to each other so as to be conductive, and further to the third electrode portion 163 of the electrode unit 106 from the outer side in the radial direction of the upper coil body 101A (ie, in the radial direction). ) And the end portion of the superconducting wire 134 disposed third from the radially inner side of the lower coil body 101B (that is, the radially outer side) are fixed in a conductive manner. The difference between the winding lengths of the superconducting wires 131 to 133 generated in the upper coil body 101A and the difference between the winding lengths of the superconducting wires 134 to 136 generated in the lower coil body 101B cancel each other. The superconducting wires 131 and 136 of the coil bodies 101A and 101B can be electrically connected, the superconducting wires 132 and 135 can be electrically connected, and the superconducting wires 133 and 134 can be electrically connected. Thus, as in the prior art, the superconducting wire 131, which is electrically connected by the first electrode portion 161 of the electrode unit 106, without providing a twisted portion at a predetermined position of the assembly in which the superconducting wires are stacked in the thickness direction, 136, a connection body composed of superconducting wires 132 and 135 electrically connected by the second electrode portion 162, and a connection body composed of superconducting wires 133 and 134 electrically connected by the third electrode portion 163. Since the total winding length over the two coil bodies 101A and 101B of the body is made substantially equal, and the difference in self-inductance of each connected body is made difficult to occur, the drift can be suppressed, so that the superconducting characteristics are sufficiently lowered. It is possible to increase the critical current of the superconducting coil 101 while suppressing the above.

  In the above-described embodiment and its modifications, an assembly conductor in which two or three superconducting wires are assembled is used, but the present invention can be achieved even when an assembly conductor composed of four or more superconducting wires is used. Applicable. That is, the first superconducting wire from the outside in the radial direction of one coil body and the first superconducting wire from the inside in the radial direction of the other coil body are electrically connected, and the second from the outside in the radial direction of the one coil body. The diameter of the n-th wire from the radially outer side of one coil body and the diameter of the other coil body is such that the superconducting wire is electrically connected to the second superconducting wire from the radially inner side of the other coil body. By electrically connecting the n-th wire from the inner side in the direction (n is a positive integer equal to or less than the number of superconducting wires), it is possible to obtain the same effect as that of the above embodiment and its modification.

  Moreover, in the said embodiment, although the edge part inside radial direction of assembly conductor 1A, 1B, ie, the end parts 31a-34a of superconducting wire 31-34, were electrically connected via the electrode unit 6, to this, Not only, but the end portions of the collective conductors 1 </ b> A and 1 </ b> B on the outer side in the radial direction, that is, the end portions 31 b to 34 b of the superconducting wires 31 to 34 are electrically connected via an electrode unit arranged on the outer side in the radial direction of the superconducting coil 1 It may be configured to. At this time, the start ends 31a to 34a of the superconducting wires 31 to 34 are respectively connected to the electrodes for external connection.

  Moreover, in the said embodiment, although the electrode unit unitized by showing electrode parts connected with an insulating material as an example of the "connection means" of this invention was shown, not only this but each electrode part is The connecting means may be provided independently without being connected.

  Next, an experiment conducted to prove the effect of the above embodiment will be described.

  That is, while preparing the specimen A by the comparative example 1 of the structure which is not contained in the said embodiment, the structure corresponding to the specimen B by the Example 1 of the structure corresponding to the said embodiment, and the modification of the said embodiment Specimens C and D according to Examples 2 and 3 were prepared, and experiments were performed to compare the characteristics of these specimens A to D.

Comparative Example 1

  Two single pancake coils were produced by stacking two tape-shaped Y-based oxide superconducting wires in the thickness direction to form a collective conductor and winding the collective conductor around a winding frame. And these single pancake coils were laminated | stacked on the axial direction, and the test body A as a superconducting coil by the comparative example 1 was produced. In this specimen A, the inner superconducting wires are connected by the upper and lower pancake coils and the outer superconducting wires are connected by the upper and lower pancake coils in the radially inner electrode unit that connects the collective conductors of each pancake coil. did. That is, the connection is not performed by switching the inner and outer positions of the collective conductor of the superconducting wire. In Specimen A of Comparative Example 1, it was found that the critical current of the entire coil was significantly less than the sum of the critical currents of the respective superconducting wires before being coiled, and significant drift occurred.

  Hereinafter, specific production procedures and measurement results of the specimen A will be shown.

1 μm of Gd—Zr oxide is deposited as an intermediate layer on four Hastelloy substrates having a thickness of 100 μm, a width of 10 mm, and a length of 20 m, and a 0.5 μm thick CeO ₂ layer is formed thereon as a cap layer. Further, a YBa ₂ Cu ₃ O _7-x superconducting film having a thickness of 1 μm was formed thereon by a CVD apparatus. Finally, an Ag layer is formed as a protective film, and a tape-like Y-based oxide superconducting wire No. 101-No. 104 was produced.

  Two superconducting wires No. 101, no. No. 102 was bent into a circular shape having a diameter of about 50 cm and immersed in liquid nitrogen, and at a temperature of 77.3 K and an external magnetic field of 0 T, two superconducting wire Nos. 101, no. The critical currents Ic101 and Ic102 of 102 were measured. At this time, the current was swept and changed at a high speed of 60 A / s. The definition of the critical current here is “when the electric field obtained by dividing the generated voltage by the distance between the voltage terminals of 20 m is 0.1 μV / cm (= 0.01 μV / mm) (that is, the generated voltage is 200 μV). Current value) ”. As a result, the critical current values were Ic101 = 147A and Ic102 = 143A.

  Next, the inner copper electrode having an inner diameter of 80 mm, an outer diameter of 100 mm, a length of 23 mm, and a width of 23 mm, a length of 16 mm, and a thickness of 5 mm fixed to the body of an FRP winding frame having a flange diameter of 160 mm On the upper half (upper side), Bi-42 wt% Sn solder of Bi-based alloy was applied and heated to a temperature range of 140 ° C. to 200 ° C. 101, no. 102 was mounted and fixed so that the Ag side was in contact with the inner copper electrode, and then cooled as it was. Thereafter, two superconducting wires No. 101, no. 102 are stacked in the thickness direction to superconducting wire No. 101 is the superconducting wire No. The superconducting wire rod No. 102 is wound around the body of the winding frame so as to be positioned on the outer side of the winding frame 102, and on the outer copper electrode similar to the inner copper electrode at the radially outer end. 101, no. 102 was soldered to give an edge treatment.

  Next, Bi-42 wt% Sn solder is applied to the lower half (lower side) of the inner copper electrode and heated to a temperature range of 140 ° C. to 200 ° C. Then, the remaining superconducting wire No. 103, no. 104 was mounted and fixed such that the Ag side was in contact with the inner copper electrode, and cooled. The superconducting wire No. at this time. 103, no. The position of 104 is the outer superconducting wire No. 101 is the lower outer superconducting wire No. 101. 103, the upper superconducting wire No. 102 is a lower inner superconducting wire No. 102. 104 are connected to each other. Then, superconducting wire No. 103, no. 104 are stacked in the thickness direction to superconducting wire No. 103 is the superconducting wire No. It is wound around the body of the winding frame so as to be located outside of the winding frame 104, and each superconducting wire No. 103, no. 104 was soldered to perform end treatment.

  Then, the obtained coil was impregnated with an epoxy resin in a vacuum to prepare a specimen A (superconducting coil) according to Comparative Example 1.

  The prepared specimen A was immersed in liquid nitrogen and energized, and the superconducting wire No. 1 was formed before coil formation. 101, no. Using the same voltage terminal where the critical current of 102 was measured, the current-voltage characteristics after coil formation were evaluated. At this time, the current was swept and changed at a high speed of 60 A / s, and the total current It flowing through the two superconducting wires was monitored. For convenience, when Itc101 and Itc102 are Itc101 = 214A and Itc102 = 204A when the voltage of each wire becomes 20 μV, respectively. Note that the voltage due to the connection resistance and the flow voltage are sufficiently smaller than the voltage due to the coil inductance. At this time, the critical currents Ic101 ′ and Ic102 ′ of the superconducting wire are reduced as compared with 0T by the magnetic field 0.1T generated in the coil, but it is considered to be reduced to about 90% in consideration of the direction and distribution of the magnetic field. Therefore, Ic101 ′ + Ic102 ′ = (Ic101 + Ic102) × 0.90 = (147 + 143) × 0.90 = 261A, Itc101 / (Ic101 ′ + Ic102 ′) = 0.82, Itc102 / (Ic101 ′ + Ic102 ′) = 0. Remarkable drift was observed, staying at a value of 78 (when current flows simultaneously up to the critical current of each wire, Itc101 / (It101 ′ + It102 ′) ≈1.0, Itc102 / (Ic101 ′ + Ic102 ′) ≈ 1.0).

  In the same manner as in Comparative Example 1, four Y-based oxide superconducting wires (No. 1 to No. 4) were cut out and immersed in liquid nitrogen in a state of being largely bent into a circular shape having a diameter of about 50 cm. In 3K, external magnetic field 0T, the wire No. 1, No. 1 When the critical currents Ic1 and Ic2 of 2 were measured, Ic1 = 151A and Ic2 = 146A. In the current measurement in Example 1 and Examples 2 and 3 below, the measurement was performed while sweeping and changing the current at a high speed of 60 A / s as in Comparative Example 1.

  Using these superconducting wires, a specimen B as a superconducting coil corresponding to the above-described embodiment was produced using a reel having the same size as that of Comparative Example 1 (see FIG. 1). In Specimen B of Example 1, the electrode unit (the “connecting means” of the present invention) arranged on the radially inner side of the superconducting coil has an FRP plate corresponding to the insulating material 63 as an electrode unit with reference to FIG. It was formed by bonding and fixing using a heat-resistant epoxy adhesive in a state sandwiched between copper block materials corresponding to 61 and 62. In addition, referring to FIG. 5, the upper and lower pancake coils were connected so that the inner superconducting wire and the outer superconducting wire were interchanged.

  The prepared specimen B was immersed in 77.3K liquid nitrogen and energized, and when Itc1 and Itc2 were evaluated in an external magnetic field of 0T, values of Itc1 = 254A and Itc2 = 246A were obtained. At this time, Itc1 / (Ic1 ′ + Ic2 ′) = 0.95, Itc2 / (Ic1 ′ + Ic2 ′) = 0.92, and a critical current of 92% or more of the total critical current of the two superconducting wires is secured. It was confirmed that the drift could be sufficiently suppressed.

  In this example, the obtained coil was impregnated with an epoxy resin in a vacuum to prepare a specimen B (superconducting coil). The impregnation of the coil is not limited to the epoxy resin, but other materials such as a phenol resin, Similar results can be obtained by using enamel resin, polyvinyl formal resin and wax.

  The above results are obtained when a Y-based oxide superconducting wire is used as the oxide superconducting wire. However, even when a Bi-based oxide superconducting wire using Ag and an Ag-based alloy sheath is used, the surface is Y-based oxide superconducting. Since Ag or an Ag-based alloy is used in the same manner as the wire, similar results are obtained.

  In addition, when the specimen B manufactured in Example 1 was evaluated for Itc1 and Itc2 in an external magnetic field of 5T at a temperature of 77.3K, 8.5A and 8.1A were obtained, and the Itc1 and Itc2 values were It has been found that it is reduced to about 1/30 compared with 0T. In the withstand voltage test between superconducting wires, dielectric breakdown occurred at 320V.

  Next, Y-based oxide superconducting wire No. 11, no. 12, a 0.05 mm thick tape-shaped support made of SUS304 is placed, and the aggregate is wrapped with 0.01 mm polyimide tape to produce an aggregate conductor. A specimen C as a superconducting coil corresponding to one modified example was prepared. At a temperature of 77.3 K and an external magnetic field of 0 T, the superconducting wire No. 11, no. When 12 critical currents Ic11 and Ic12 were measured, Ic11 = 153A and Ic12 = 148A.

  The produced specimen C was immersed in 77.3K liquid nitrogen and energized, and when Itc11 and Itc12 were evaluated in an external magnetic field of 0T, values of 257A and 252A were obtained. At this time, Itc11 / (Ic11 ′ + Ic12 ′) = 0.95 and Itc12 / (Ic11 ′ + Ic12 ′) = 0.93, ensuring a critical current of 93% or more of the total critical current of the two superconducting wires. It was confirmed that the drift could be sufficiently suppressed.

  When the specimen C produced in Example 2 was evaluated for Itc11 and Itc12 in an external magnetic field of 5T at a temperature of 77.3K, values of 29.3A and 29.7A were obtained, compared with Example 1. It was found that Itc11 and Itc12 more than 3 times were obtained in the external magnetic field 5T. Moreover, it was confirmed in the withstand voltage test between superconducting wires that dielectric breakdown did not occur even at 1 kV, and it was found that the conditions for application to power application equipment were greatly relaxed.

  Next, two 120m long Y-based oxide superconducting wires (No. 20, No. 30) were prepared, and one of them (No. 20) was cut into approximately three equal parts in the length direction. Superconducting wire No. obtained 21, no. 22, no. A portion having a length of 100 mm was cut out from 23, cooled to a temperature of 77.3K, and critical currents Ic21, Ic22, and Ic23 were measured with an external magnetic field of 0T. The results were Ic21 = 151A, Ic22 = 156A, and Ic23 = 153A.

  Superconducting wire No. 21, no. 22, no. No. 23 is wound around the FRP frame used in Example 1 so as to form a double pancake type (No. 21, No. 22, No. 23 in order from the radially outer side) to produce an upper pancake coil. Then, the outer copper electrode shown in Example 1 and each superconducting wire were connected to each other at the upper outer periphery using Bi-42 wt% Sn solder.

  Then, another superconducting wire (No. 30) was cut into approximately three equal parts in the length direction to obtain a superconducting wire No. 31, no. 32, no. No. 33, No. 32, No. 33 in order from the outside to form a double pancake type on another FRP winding frame to produce a lower pancake coil, and the outer circumference of the lower stage The outer copper electrode and each superconducting wire were connected to each other using Bi-42 wt% Sn solder.

  Then, the upper and lower pancake coils are connected by an electrode unit (connecting means) arranged on the radially outer side. Each superconducting wire No. 21, no. 22, no. 23 are superconducting wire Nos. 33, no. 32, no. A specimen 42 as a superconducting coil corresponding to another modified example of the above embodiment is manufactured by connecting with Bi-42 wt% Sn solder so as to be connected to No. 31, and finally impregnating with epoxy resin in a vacuum. did.

  The prepared specimen D was immersed in 77.3K liquid nitrogen and energized, and when itc2, itc22, and itc23 were evaluated in an external magnetic field of 0T, values of 350A, 339A, and 346A were obtained. At this time, the critical currents Ic21 ′, Ic22 ′, and Ic23 ′ of the superconducting wire are reduced compared to 0T by the magnetic field 0.25T generated in the coil, but it is considered to be reduced to about 80% in consideration of the direction and distribution of the magnetic field. It is done. Therefore, Ic21 ′ + Ic22 ′ + Ic23 ′ = (Ic21 + Ic22 + Ic23) × 0.80 = (151 + 156 + 153) × 0.80 = 368 A, but Itc21 / (Ic21 ′ + Ic22 ′ + Ic23 ′) = 0.95, Itc22 / (Ic21 ′ + Ic22 ′ + Ic23 ′) = 0.92, Itc23 / (Ic21 ′ + Ic22 ′ + Ic23 ′) = 0.94, and a critical current of 92% or more of the total critical current of the three superconducting wires can be secured. It was confirmed that the drift was sufficiently suppressed.

It is the perspective view which showed the whole structure of the superconducting coil by one Embodiment of this invention. It is a perspective view for demonstrating the structure of the assembly conductor of the superconducting coil shown in FIG. It is sectional drawing along the III-III line in FIG. It is sectional drawing along the IV-IV line in FIG. It is the front view which showed the principal part structure of the electrode unit which electrically connects the coil bodies of the superconducting coil shown in FIG. It is the perspective view which showed the whole structure of the superconducting coil by a modification. It is sectional drawing along the VII-VII line in FIG. It is the front view which showed the structure of the electrode unit which electrically connects the coil bodies of the superconducting coil shown in FIG. It is the perspective view which showed the structure of the dislocation segment in the aggregate | assembly of the conventional superconducting wire.

Explanation of symbols

1,101 Superconducting coils 1A, 101A Upper coil body (first coil body)
1B, 101B Lower coil body (second coil body)
2,102 reels 31-34, 131-136 superconducting wire 6,106 electrode unit (connecting means)
61,161 First electrode part (electrode part)
62,162 Second electrode part (electrode part)
63,164 Insulation material (insulating material)
163 Third electrode part (electrode part)

Claims (7)

A first coil body; a second coil body adjacent to the first coil body in the axial direction; and a connecting means for electrically connecting the first coil body and the second coil body. A superconducting coil,
The first coil body and the second coil body are respectively
A predetermined number of tape-like superconducting wires connected to the connecting means;
These superconducting wires are in a state of being superposed in the thickness direction of the superconducting wires, and include a winding frame for concentrically winding in the overlapping order,
The connection means includes a predetermined number of electrode portions equal to the number of superconducting wires constituting the coil body,
When n is an arbitrary positive integer equal to or less than the number of the superconducting wires, the end of the superconducting wire arranged nth from the radial outside of the first coil body, and the second coil body The ends of the superconducting wires arranged nth from the radially inner side are aligned in the axial direction of the coil body, and are fixed to the common electrode portions so as to be electrically conductive,
And the superconducting wire of the said 1st coil body and the superconducting wire of the said 2nd coil body which pinch | interpose the said electrode part are wound by the said winding frame in the mutually opposite direction, The superconducting coil characterized by the above-mentioned. The coil bodies of the coil bodies have outer diameter dimensions substantially equal to each other,
The superconducting coil according to claim 1, wherein the superconducting wire is wound around the winding frame at a predetermined number of turns. The predetermined number of electrode portions are arranged along the winding direction of the superconducting wire, and are provided across the two coil bodies in a manner extending in the axial direction of the coil body,
The superconducting wire is extended to a position where the end of the superconducting wire disposed in the radially inner side extends over the end in the winding direction, and is connected to the electrode portion at the position. The superconducting coil according to claim 1 or 2.   An end portion of the superconducting wire of the first coil body and an end portion of the superconducting wire of the second coil body corresponding to the superconducting wire are connected to the same surface of the electrode portion. The superconducting coil according to claim 3.   The electrode portion is an electrode portion connected to an end portion on the radially inner side of the superconducting wire, and the winding frame is connected so that a connection surface with the superconducting wire is substantially flush with an outer peripheral surface of the winding frame. The superconducting coil according to claim 4, wherein the superconducting coil is embedded in the coil.   The superconducting coil according to any one of claims 3 to 5, wherein the adjacent electrode parts are connected via an insulating member.   The superconducting coil according to any one of claims 1 to 6, further comprising a tape-like support body arranged along the superconducting wire and wound around the winding frame together with the superconducting wire. .

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