JP2010287349A - Terminal structure of superconducting cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terminal structure of a superconducting cable capable of alleviating resistance of a connection site of a superconducting thin film of a superconducting conductor layer and normally conducting conductor part. <P>SOLUTION: The terminal structure is provided with a superconducting conductor layer 113 of the superconducting cable, and a normally conducting conductor part 353 connected with the superconducting conductor layer for exchanging power with an equipment of normal temperature side. The superconducting conductor layer 113 is structured by spirally winding superconducting wire rods 2 having a superconducting thin film 26 formed on the substrate 22 so as the superconducting thin film 26 to be at an inner periphery side and the substrate 22 at an outer periphery side. The terminal structure is provided with a normally conducting connection member 4 having a jointing face 42 adjacent to the superconducting thin film 26, a connecting-use superconducting sheet 5 equipped with a superconducting layer 56 facing the superconducting thin film 26 so as to be astride the jointing face 42, and a conductive jointing material 6 jointing to superconducting layer 56 with both the superconducting thin film 26 and the jointing face 42. The normally conducting connection member 4 is provided with a through-hole 44 for guiding the conductive jointing material 6 to the jointing face 42 from its outer periphery face. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a terminal structure of a superconducting cable. In particular, the present invention relates to a terminal structure of a superconducting cable including a superconducting conductor layer in which a superconducting thin film of a superconducting wire having a superconducting thin film is spirally wound toward the inner peripheral side of the cable.

  A superconducting cable is expected as an energy-saving technology because it can transmit a large amount of current with low loss compared to a normal conducting cable. Recently, demonstration tests of superconducting cables have been conducted for practical use.

  In general, as shown in FIG. 3, the superconducting cable has a heat insulating tube 10 having an inner tube 10B inside an outer tube 10A, and one or more cores 11 are accommodated in the inner tube. The core 11 includes a core material 111, a superconducting conductor layer 113, an insulating layer 115, a superconducting shield layer 117, and a protective layer 119 in order from the center toward the outer peripheral side.

  As the superconducting conductor layer 113, there is one using a superconducting wire 2 having a superconducting thin film as shown in FIG. Specifically, the superconducting wire 2 in which the superconducting thin film 26 is formed on the normal conducting substrate 22 is spirally wound so that the substrate 22 is on the outer peripheral side and the superconducting thin film 26 is on the inner peripheral side. (See FIG. 3) (Patent Document 1). If the superconducting thin film 26 is a superconducting conductor layer facing the inner peripheral side of the core, the compressive strain acts on the superconducting thin film 26 inside the bend and the tensile strain acts on the substrate 22 outside the bend. The current is difficult to decrease.

  At the end of such a superconducting cable, a terminal structure is installed in order to exchange power with a device installed on the room temperature side, for example, a normal conducting cable.

  Conventionally, the terminal structure shown in FIG. 2 is known as this terminal structure (see Patent Document 2). The terminal structure includes a refrigerant tank housed in a vacuum tank. The vacuum layer includes a main vacuum chamber 301 and a connection vacuum chamber 302 connected to the side surface of the main vacuum chamber 301. Similarly, the refrigerant tank includes a main refrigerant tank 311 and a connected refrigerant tank 312 connected to the side surface of the main refrigerant tank 311. The upper end of the bushing 351 connected to a normal conducting cable (not shown) sequentially passes through the main refrigerant tank 311 and the main vacuum tank 301 and is drawn out of the main vacuum tank 301. On the other hand, the lower end of the bushing 351 is connected to one end of the normal conducting conductor portion 353 inside the main refrigerant tank 311. The core superconducting conductor layer 113 drawn from the end of the superconducting cable 1 and the other end of the normal conducting conductor 353 are connected inside the connection refrigerant tank 312.

JP 2007-188844 A JP 2006-196628 A

  However, the above-described conventional technology does not disclose a specific connection structure between the superconducting conductor layer and the normal conducting conductor portion of the superconducting cable.

  Here, as a connection structure between the superconducting conductor layer and the normal conductor portion, a normal conducting sleeve (normal conducting connecting member) is fitted on the outer periphery of the superconducting conductor layer, and solder is poured between the superconducting conductor layer and the normal conducting connecting member. Assume that.

  However, in the case of such a connection structure, the superconducting thin film is connected to the normal conducting connecting member via the normal conducting substrate located on the outer peripheral side of the superconducting conductor layer. As a result, it is expected that the resistance at the connection location will increase.

  The present invention has been made in view of the above circumstances, and one of its purposes is a terminal of a superconducting cable that can reduce the resistance of a connection portion between a superconducting conductor layer having a superconducting thin film and a normal conducting conductor. To provide a structure.

  The terminal structure of the superconducting cable of the present invention is a terminal structure of a superconducting cable comprising a superconducting conductor layer of the superconducting cable and a normal conducting conductor portion connected to the superconducting conductor layer and for inputting / outputting electric power to / from a room temperature side device. Related. The superconducting conductor layer is formed by winding a superconducting wire having a superconducting thin film formed on a substrate in a spiral shape so that the superconducting thin film is on the inner peripheral side and the substrate is on the outer peripheral side. This terminal structure includes a normal conducting connecting member, a connecting superconducting sheet, and a conductive bonding material. The normal conducting connection member has one end connected to the normal conducting conductor and the other end having a joint surface adjacent to the superconducting thin film. The connection superconducting sheet includes a superconducting layer facing the superconducting thin film so as to straddle the joint surface. The conductive joining material joins the superconducting thin film and the superconducting layer of the connecting superconducting sheet, and joins the joining surface and the superconducting layer of the connecting superconducting sheet. The normal conducting connecting member includes a through hole for introducing the conductive bonding material from the outer peripheral surface to the bonding surface.

  According to this configuration, since the superconducting thin film and the normal conducting connecting member are connected by the conductive bonding material without using a high-resistance substrate, the resistance at the connection location can be reduced.

  In the terminal structure of the superconducting cable according to the present invention, a plurality of superconducting wires are laminated in the radial direction, and the end of the superconducting conductor layer is connected to the end of the superconducting wire on the inner layer side from the end of the superconducting wire on the outer layer side. For example, the superconducting thin film of each layer may be formed stepwise by extending the length in the end direction. In that case, the joining surface is formed in a stepped manner so as to be adjacent to the superconducting thin film of each layer.

  With this configuration, the superconducting thin film of each layer at the end of the laminated superconducting conductor layer can be formed stepwise. Then, the superconducting thin film of each layer is arranged so as to be adjacent to the stepped joining surface, and the superconducting thin film of each layer is almost bent by connecting the superconducting thin film and the joining surface of each layer through the connection superconducting sheet. Nor.

  In the terminal structure of the superconducting cable of the present invention, the superconducting layer of the superconducting sheet is preferably made of the same material as the superconducting thin film of the superconducting wire.

  According to this configuration, since the superconducting layer joined to the superconducting thin film is made of the same material, mismatching hardly occurs between the two electrically and mechanically. Further, if the superconducting sheet is configured to include a substrate and a superconducting thin film in the same manner as the superconducting wire of the superconducting conductor layer, the superconducting sheet can be manufactured using the superconducting wire manufacturing line.

Furthermore, the terminal structure of the present invention can be obtained by the following assembly method. That is, this assembling method is a method of assembling a terminal structure of a superconducting cable including a superconducting conductor layer of a superconducting cable and a normal conducting conductor portion connected to the superconducting conductor layer for transmitting and receiving power to a room temperature side device. The method includes the following steps.
A step of exposing an end portion of the superconducting conductor layer formed by spirally winding a superconducting wire having a superconducting thin film formed on a substrate so that the superconducting thin film is on the inner peripheral side and the substrate is on the outer peripheral side.
A cylindrical member having a normal conductive connecting member having one end connected to the normal conductive conductor portion and having a joint surface on the other end and a through hole connecting the joint surface and the outer peripheral surface; A step of arranging the bonding surface and the superconducting thin film so as to be adjacent to each other.
A step of causing the superconducting layer of the connecting superconducting sheet to face the superconducting thin film and the joining surface so as to straddle the superconducting thin film and the joining surface.
Connecting the superconducting layer of the superconducting sheet and the superconducting thin film and the superconducting layer of the superconducting sheet and the joining surface with a conductive joining material introduced from a through-hole of the normal conducting connecting member.

  In this assembling method, a part of the superconducting sheet for connection may be first faced to the joint surface, and then the superconducting thin film may be faced to the rest of the sheet, and then the above-described connection using the conductive joint material may be performed. The superconducting thin film of the superconducting conductor layer is bonded in advance with a part of the superconducting sheet for connection with a conductive bonding material, and then the remaining part of the sheet faces the bonding surface, and then the connection superconducting sheet with the conductive bonding material and You may connect with a joint surface.

  According to the terminal structure of the superconducting cable of the present invention, the superconducting thin film and the normal conducting connecting member can be connected by the conductive bonding material without going through the substrate, and the resistance at the connecting portion can be reduced.

It is a principal part longitudinal cross-sectional view of the terminal structure of the superconducting cable which concerns on Embodiment 1 of this invention. It is sectional drawing of the terminal structure of a superconducting cable. It is a cross-sectional view of a superconducting cable. It is a schematic perspective view which shows the structure of a thin film superconducting wire. It is a principal part longitudinal cross-sectional view of the terminal structure of the superconducting cable which concerns on the modification of Embodiment 1.

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

[Embodiment 1]
〔overall structure〕
A terminal structure according to the first embodiment will be described with reference to FIGS. In each figure, the same reference numerals are assigned to the same members. As shown in FIG. 2, the terminal structure of this example includes a superconducting cable 1 and a terminal container portion 3 formed at the end thereof.

<Superconducting cable>
Although only one core is shown in FIG. 2, the superconducting cable 1 has a structure in which three cores 11 are housed in a heat insulating tube 10 as shown in FIG. The heat insulating tube 10 is constituted by a heat insulating double tube in which the space between the outer tube 10A and the inner tube 10B is evacuated, and a radiation heat insulating material (not shown) is disposed between the outer tube 10A and the inner tube 10B. On the other hand, the core 11 includes a core material 111, a superconducting conductor layer 113, an insulating layer 115, a superconducting shield layer 117, and a protective layer 119 in order from the center toward the outer peripheral side.

  Among these, the superconducting conductor layer 113 has a configuration in which a plurality of superconducting wires are spirally wound around the outer periphery of the core material 111 to form a single layer, and a plurality of the single layers are stacked in the radial direction of the core 11. As this superconducting wire, one having a superconducting thin film 26 is used as shown in FIG. For example, the superconducting wire 2 having a laminated structure in which the intermediate layer 24, the superconducting thin film 26, and the stabilizing layer 28 are sequentially formed on the substrate 22 is used. Each superconducting wire 2 is spirally wound so that the superconducting thin film 26 is on the inner peripheral side of the core (FIG. 3) and the substrate 22 is on the outer peripheral side.

<Outline of terminal container>
On the other hand, the terminal container unit 3 is connected to the storage unit 30 including the refrigerant tank stored in the vacuum chamber, and the end of the superconducting cable 1, and is connected to the normal conduction through the vacuum layer and the refrigerant layer to the room temperature side. It has the power transmission part 35 (FIG. 2). The vacuum layer includes a main vacuum chamber 301 and a connection vacuum chamber 302 connected to the side surface of the main vacuum chamber 301. Similarly, the refrigerant tank includes a main refrigerant tank 311 and a connected refrigerant tank 312 connected to the side surface of the main refrigerant tank 311. Further, the normal conducting power transmission unit 35 includes a bushing 351, a normal conducting conductor portion 353, and a connecting portion 355 as main components. The upper end of the bushing 351 connected to the normal conducting cable (not shown) sequentially passes through the main refrigerant tank 311 and the main vacuum tank 301 and is drawn out of the main vacuum tank 301. On the other hand, the lower end of the bushing 351 is connected to one end of the normal conductive portion 353 and a connection portion 355 inside the main refrigerant tank 311. Then, the superconducting conductor layer 113 drawn from the end of the superconducting cable 1 and the other end of the normal conducting conductor 353 are connected inside the connection refrigerant tank 312.

[Configuration of each part]
The most characteristic feature of the terminal structure of the present invention is the connection structure between the superconducting conductor layer and the normal conducting conductor. As shown in FIG. 1, this connection structure includes an end portion of a superconducting cable, a normal conducting conductor portion 353, a normal conducting connecting member 4, a connecting superconducting sheet 5, and a conductive bonding material 6.

<End of superconducting cable>
At the end of the superconducting cable as shown in FIG. 3, the layers from the core material 111 constituting the core 11 to the superconducting shield layer 117 are exposed stepwise. The core material 111 is a stranded wire composed of a plurality of copper wires, and the superconducting wire 2 (FIG. 4) constituting the superconducting conductor layer 113 and the superconducting shield layer 117 is a RE123-based wire (RE: rare earth element, for example, Y, Ho, Nd, Sm, Gd, etc.) and PPLP (registered trademark) in which polypropylene and kraft paper are laminated can be used for the insulating layer 115. In particular, the superconducting conductor layer 113 (FIG. 1) uses the superconducting wire 2 in which the superconducting thin film 26 is spirally wound toward the inside of the core. Thus, the superconducting wire 2 can be wound.

  Among them, as shown in FIG. 1, each layer of the superconducting conductor layer 113 having a laminated structure is configured so as to become longer in the cable shaft end direction (right side in FIG. 1) from the outer layer toward the inner layer. That is, the end of each layer of the superconducting conductor layer 113 is the end of the superconducting wire 2 on the outer layer side with the substrate 22 of the superconducting wire on the inner layer side, with the superconducting thin film 26 facing the inner peripheral side of the core with respect to the substrate 22. To be exposed stepwise. The process for forming the end portion of the superconducting conductor layer 113 stepwise may be the same as the so-called step peeling generally performed at the end portion of the cable, and does not require any special skill. If necessary, the stabilization layer 28 (see FIG. 4) on the superconducting thin film 26 is mechanically or chemically removed at the end of each layer of the superconducting conductor layer 113 to remove the superconducting thin film 26 in the superconducting conductor layer 113. You may expose to the circumference side. Thereby, a connection structure with a lower resistance can be configured. That is, the joining between the superconducting thin film 26 and the joining surface of the normal conducting connecting member 4 to be described later may be a direct joining or an indirect joining with the stabilization layer 28 interposed therebetween, which is equal to or more than the substrate 22. It is not necessary to intervene a material having the following resistance.

  However, in FIG. 1, for convenience of explanation, the stage state of the superconducting wire 2 at the end of the superconducting conductor layer 113 is exaggerated. In general, the thickness of one superconducting wire 2 is about 100 to 200 μm. Although omitted in FIG. 1, interlayer insulation is provided between the layers of the superconducting conductor layer 113, and the thickness thereof is about 140 μm. On the other hand, in this example, of the pair of superconducting wires 2 adjacent to each other in the radial direction of the core, the dimension (protrusion amount) of the inner layer protruding in the cable shaft end direction from the outer layer is about 15 to 20 mm. Therefore, at the end of the actual superconducting conductor layer 113, the amount of protrusion is approximately 100 times or more than the thickness of one superconducting wire 2, and a step state in which one step is about 240 to 340 μm is formed. The

<Normal conductor part>
The normal conducting conductor 353 (FIGS. 1 and 2) is a conductor for electrically connecting the superconducting conductor layer 113 of the superconducting cable and the end of the bushing 351 disposed in the terminal container 3. . The normal conducting conductor 353 has a cross-sectional area corresponding to the capacity of the current from the superconducting cable 1 or the current from the bushing 351, for example, a bar made of a high conductivity material such as copper or copper alloy, or a twisted material. Consists of lines. Here, the normal conductor portion 353 is composed of a stranded wire composed of a plurality of copper strands and having substantially the same diameter as the core material 111 (FIG. 3) of the superconducting cable.

<Normal conductive connection member>
The normal conducting connection member 4 is a member for connecting the superconducting conductor layer 113 of each core and the normal conducting conductor portion 353 (FIG. 1). In this example, a copper sleeve material is used as the normal conducting connection member 4. A normal conductive conductor part 353 is fitted inside the one end side of the normal conductive connecting member 4, and a core material 111 is fitted inside the other end side. The normal conducting conductor portion 353 and the core material 111 are compression-connected by the normal conducting connecting member 4 that covers the butted portion of both.

  A step-like joining surface 42 is formed on the inner circumference of the other end side (superconducting cable side) of the normal conducting connection member 4. The joining surface 42 is configured such that the inner diameter gradually decreases from the other end (superconducting cable side) of the normal conducting connection member 4 to one end (normal conducting conductor side), and the end of the superconducting conductor layer 113. It is formed so as to correspond to the stage state of each layer in the part. That is, the joining surface 42 is configured in a stepped manner so that it can be arranged in parallel at the same position in the radial direction of the superconducting thin film 26 and the core in each layer of the superconducting conductor layer 113. The other end portion of the normal conducting connection member 4 has a small inner / outer diameter difference and is thinned. Therefore, an appropriate thickness is selected in consideration of the current capacity from the outermost superconducting conductor layer 113. The superconducting thin film 26 of each layer of the superconducting conductor layer 113 is disposed adjacent to the joint surface 42 of each step. In FIG. 1, the stepped state of the joint surface 42 is exaggerated and is the same as that of the end portion of the superconducting conductor layer 113.

  Further, a through hole 44 is formed on the other end side of the normal conducting connection member 4 from the outer peripheral surface to the joining surface 42. As in this example, when the joint surfaces 42 are formed in stages, a plurality of through holes 44 are provided so as to reach each of the joint surfaces 42 at each stage. The through hole 44 introduces a conductive bonding material 6 described later from the outer peripheral surface of the normal conducting connection member 4 to the bonding surface 42. The cross-sectional shape of the through hole 44 is not particularly limited, and may be a polygon or an ellipse. A circular shape is preferable because it can be easily processed. In addition, the cross-sectional area of the through hole 44 may be set to a size that does not cause an excessive decrease in strength on the other end side of the normal conductive connecting member 4 and that allows the conductive bonding material 6 to be introduced quickly. Furthermore, the opening position of the through hole 44 in the joint surface 42 is preferably an intermediate position in the axial direction of the joint surface 42 in the longitudinal section of the normal conducting connection member 4. By forming the opening of the through hole 44 at this intermediate position, the conductive bonding material 6 can be easily spread over the entire bonding surface.

  On the other hand, the outer peripheral surface on one end side (normal conducting conductor portion side) of the normal conducting connecting member 4 is formed in a tapered shape whose outer diameter becomes smaller toward the end portion side. This shape prevents the electric field from concentrating on the boundary portion between the normal conductive conductor portion 353 and the normal conductive connection member 4.

<Superconducting sheet for connection>
The connection superconducting sheet 5 is a member for electrically connecting the superconducting thin film 26 of each layer of the superconducting conductor layer 113 and the joint surface 42 of the normal conducting connecting member. This connection superconducting sheet 5 includes a superconducting layer 56. Typically, a superconducting wire 2 having the same configuration as that of the superconducting conductor layer 113 can be used as the superconducting sheet 5 for connection. Usually, a superconducting wire is manufactured by first producing a long sheet in which an intermediate layer, a superconducting thin film, and a stabilizing layer are sequentially formed on a substrate, and then cutting the long sheet into a predetermined wire width. Yes. Therefore, the connecting superconducting sheet 5 can be easily obtained by adjusting the cutting width of the long sheet. In this case, the long sheet substrate becomes the superconducting sheet substrate 52, and the long sheet superconducting thin film becomes the superconducting layer 56 of the connecting superconducting sheet. In this example, a strip-shaped sheet having a width of about 30 mm is used as the superconducting sheet 5 for connection. Of course, the configuration of the connecting superconducting sheet 5 is not limited to the same laminated structure with the same material as the superconducting wire 2.

  Such a connection superconducting sheet 5 is disposed so that the superconducting layer 56 straddles both the superconducting thin film 26 of each layer of the superconducting conductor layer 113 and the joint surface 42 of the normal conducting connecting member. For example, the connection superconducting sheet 5 is made to make one turn along the circumferential direction of the core so that the superconducting layer 56 is directed to the outer peripheral side of the core and the substrate 52 is directed to the inner peripheral side of the core. At that time, approximately half of the width of the superconducting layer 56 in the connecting superconducting sheet 5 faces the superconducting thin film 26 of each layer of the superconducting conductor layer 113, and the other half faces the joint surface 42 of the normal conducting connecting member. To. With such an arrangement of the connecting superconducting sheet 5, the superconducting thin film 26 of the superconducting conductor layer and the joint surface 42 of the normal conducting connecting member are electrically connected via the superconducting layer 56 of the connecting superconducting sheet.

<Conductive bonding material>
The conductive joining material 6 is used for joining the superconducting thin film 26 of the superconducting conductor layer and the superconducting layer 56 of the connecting superconducting sheet, and joining the joining surface 42 of the normal conducting connecting member and the superconducting layer 56 of the connecting superconducting sheet. Specifically, solder can be used. Low melting point solder may be used. With this conductive bonding material 6, between the superconducting thin film 26 of the superconducting conductor layer and the superconducting layer 56 of the connecting superconducting sheet, and between the bonding surface 42 of the normal conducting connecting member and the superconducting layer 56 of the connecting superconducting sheet, Only the solder and the stabilization layer 28 (FIG. 4) are interposed, and the high resistance substrate 22 is not interposed. Even a material other than solder can be used as the conductive bonding material 6 as long as it is a material that can connect these bonding portions with low resistance and can obtain appropriate bonding strength mechanically. Although the inside of the through hole 44 is shown as a hollow in FIG. 1, the inside of the through hole may be filled with a conductive bonding material.

[Assembly method]
The above-described terminal structure of the present invention is assembled as follows.

  First, the end of the superconducting cable 1 (see FIG. 3) is stepped off, and the layers from the core material 111 constituting the core to the superconducting shield layer are exposed stepwise. At this stage, the end portions of the respective layers of the superconducting conductor layer are all set to the same length.

  Next, from the end portion of the superconducting conductor layer 113, the superconducting wire 2 of each layer wound spirally is once spread and unwound.

  On the other hand, the normal conducting conductor part 353 is inserted from one end side of the normal conducting connecting member 4 and the core material 111 of the core is inserted from the other end side, so that the end face of the normal conducting conductor part and the end face of the core material are abutted (FIG. 1). ). In this state, the normal conducting connection member 4 is compressed by a compressor. This compression is performed on a portion of the normal conducting connecting member 4 that is shifted from a portion where the joining surface 42 is located to one end side (right side in FIG. 1) of the connecting member 4. By this compression, the normal conducting conductor portion 353 and the core material 111 are compressed and connected by the normal conducting connecting member 4.

  Subsequently, the ends of the superconducting wire 2 of each layer that has been unraveled are cut. Specifically, the superconducting wire 2 of each layer is cut by taking a larger cutting allowance for the superconducting conductor layer 113 on the outer layer side. At that time, of the pair of superconducting conductor layers 113 adjacent to each other in the radial direction of the core, the protruding amount of the inner layer protruding in the core axial direction from the outer layer corresponds to about half of the width of the connecting superconducting sheet 5. Select a cutting allowance. By this cutting, each layer of the superconducting conductor layer 113 is configured so as to become longer in the cable shaft end direction from the outer layer toward the inner layer.

  When this cutting is finished, the connecting superconducting sheet 5 is arranged at the end of each layer of the superconducting conductor layer 113. The arrangement of the sheet 5 is such that the connecting superconducting sheet 5 is made to make one turn along the circumferential direction of the core so that the superconducting layer 56 is directed to the outer peripheral side of the core and the substrate 52 is directed to the inner peripheral side of the core. Do.

  First, the connecting superconducting sheet 5 on the inner layer side is wound around the outer periphery of the core material 111. At that time, approximately half of the superconducting layer 56 in the width direction of the connecting superconducting sheet 5 faces the innermost joint surface 42 of the normal conducting connecting member 4. Thereafter, the superconducting wire 2 of the inner layer that has been unraveled is returned to its original state, and the superconducting thin film 26 of the same wire 2 is made to face the superconducting layer 56 of the connecting superconducting sheet.

  Next, the connecting superconducting sheet 5 on the outer layer side is similarly wound on the inner layer of the superconducting conductor layer 113. At that time, approximately half of the superconducting layer 56 in the width direction of the connecting superconducting sheet 5 faces the joining surface 42 of the next stage from the inner peripheral side of the normal conducting connecting member 4. Thereafter, the undissolved outer layer superconducting wire 2 is returned to its original state, and the superconducting thin film 26 of the same wire 2 is made to face the superconducting layer 56 of the connecting superconducting sheet on the outer layer side.

  In the case where the superconducting conductor layer has a laminated structure of three or more layers and there are three or more bonding surfaces, similarly, the operation of winding the superconducting sheet for connection and returning the unraveled superconducting wire may be repeated.

  Then, between the superconducting thin film 26 of the superconducting conductor layer and the superconducting layer 56 of the connecting superconducting sheet and between the joining surface 42 of the normal conducting connecting member and the superconducting layer 56 of the connecting superconducting sheet are joined by the conductive joining material 6. To do. Specifically, the solder 6 is filled from the opening of the through hole 44 located on the outer peripheral surface of the normal conducting connection member 4. By this filling, the solder 6 reaches the joint surface 42 through the through hole 44. The solder 6 enters between the joining surface 42 and the superconducting layer 56 of the connecting superconducting sheet, and also enters between the superconducting thin film 26 of the superconducting conductor layer and the superconducting layer 56 of the connecting superconducting sheet. Then, the superconducting layer 56 of the connecting superconducting sheet is joined so as to straddle the superconducting thin film 26 and the joining surface 42 of the superconducting conductor layer.

  Thereafter, as shown in FIG. 2, a reinforcing insulating layer 357 is formed on the exposed portion of the superconducting conductor layer 113 and the outer periphery of the normal conducting connecting member 4.

[Function and effect]
According to such a terminal structure of the present invention, when the superconducting conductor layer is composed of a superconducting wire wound with the superconducting thin film as the inner peripheral side from the substrate, the joint surface between the superconducting thin film and the normal conducting connecting member A high resistance substrate is not interposed between the two. As a result, the resistance at this joint can be reduced.

  In addition, since the superconducting thin film of each layer of the superconducting conductor layer and the joining surface of the normal conducting connecting member are disposed adjacent to each other, the superconducting wire of each layer can be electrically connected to the joining surface without bending. For this reason, the distortion associated with the bending does not act on the end of each superconducting wire, and the size in the core radial direction at the connecting portion between the superconducting conductor layer and the normal conducting connecting member does not increase.

  Further, since the superconducting thin film of each layer of the superconducting conductor layer and the joint surface of the normal conducting connecting member are arranged adjacent to each other, the superconducting conductor layer can be obtained simply by abutting the end of the superconducting conductor layer with the end of the normal conducting connecting member. And the normal conducting connecting member can be positioned.

[Modification]
Next, as a modification of the first embodiment, a configuration in which the normal conductive conductor portion and the normal conductive connection member are connected by tightening bolts will be described with reference to FIG. The main difference between this example and Embodiment 1 is in the connection structure of a normal conducting conductor part and a normal conducting connection member, and since other structures are substantially the same as those in Embodiment 1, the description thereof is omitted.

  The normal temperature side end of the normal conductive connecting member 4 has a flat terminal portion 46 connected to the normal conductive conductor portion 353, and the flat terminal portion 46 has a plurality of bolt holes 46h (see FIG. 5B). Have. On the other hand, the normal conducting conductor portion 353 facing the terminal portion 46 also has a flat plate-like end portion having a bolt hole (not shown). To connect the normal conductive connecting member 4 and the normal conductive conductor part 353, first, the bolt terminal holes of the flat conductive terminal part 46 and the flat end of the normal conductive conductor part 353 are matched. Overlapping to do. Then, a bolt (not shown) is passed through both bolt holes, and a nut (not shown) is fastened to the bolt. As a result, the normal conductive connecting member 4 and the normal conductive conductor portion 353 can be easily and firmly connected.

  On the other hand, as shown in FIG. 5A, the normal conductive connecting member 4 and the core material 111 are connected by inserting the core material 111 into the normal conductive connecting member 4 and compressing the normal conductive connecting member 4 with a compressor. This compression is performed on the portion between the joining surface 42 of the normal conducting connecting member 4 and the connecting superconducting sheet 5 and the flat terminal portion 46. By this compression, the core material 111 and the normal conducting connection member 4 are compressed and connected.

  Further, the normal conducting connection member 4 may be provided with multi-contacts (trade names, not shown) at locations other than the joint surface 42 on the inner peripheral surface thereof. The multi-contact has a plurality of conductive contacts. By inserting the core material 111 into the normal conducting connection member 4 using this multi-contact, a plurality of contacts press-contact the core material 111, and the normal conducting connection member 4 and the core material 111 are electrically and mechanically connected. For this reason, if the multi-contact is used, it is not necessary to provide a compression point in the normal conductive connecting member 4, so that the normal conductive connecting member 4 can be shortened, and further, the compression work by the compressor becomes unnecessary.

[Others]
The scope of the present invention is not limited to the above embodiment, and various modifications are possible. In the above embodiment, only two superconducting conductor layers are shown, but the number of layers is not particularly limited, and may be a single layer or three or more layers. Further, the assembling method is not limited to the above procedure. For example, before compressing the normal conducting connection member, each layer of the superconducting conductor layer may be cut in advance to a predetermined length. In addition, after preliminarily joining a part of the superconducting layer of the superconducting sheet for connection to the superconducting thin film of each layer of the superconducting conductor layer with a conductive joining material, and then facing the superconducting layer of the remaining part of the sheet to the joining surface, The superconducting layer and the bonding surface may be connected by a conductive bonding material.

  The terminal structure of the superconducting cable of the present invention can be suitably used in a superconducting cable using a superconducting thin film. In particular, it can be suitably used for a terminal structure in which resistance at a connection portion between the superconducting thin film and the normal conducting connecting member is reduced.

1 Superconducting cable
10 Insulated pipe
10A outer tube 10B inner tube
11 core
111 Core material 113 Superconducting conductor layer 115 Insulating layer
117 Superconducting shield layer 119 Protective layer 2 Superconducting wire
22 Substrate 24 Intermediate layer 26 Superconducting thin film 28 Stabilization layer 3 Terminal container
30 compartment
301 Main vacuum tank 302 Connection vacuum tank 311 Main refrigerant tank 312 Connection refrigerant tank
35 Normal conducting power transmission
351 Bushing 353 Normal conducting conductor part 355 Connection part 357 Reinforcement insulation layer 4 Normal conducting connection part
42 Joint surface 44 Through hole 46 Flat terminal 46h Bolt hole 5 Superconducting sheet for connection
52 Substrate 56 Superconducting layer 6 Conductive bonding material (solder)

Claims (3)

A terminal structure of a superconducting cable comprising a superconducting conductor layer of a superconducting cable and a normal conducting conductor portion connected to the superconducting conductor layer for transmitting and receiving electric power with a device on the room temperature side,
The superconducting conductor layer is formed by winding a superconducting wire having a superconducting thin film formed on a substrate in a spiral shape so that the superconducting thin film is on the inner peripheral side and the substrate is on the outer peripheral side,
This terminal structure is
A normal conducting connecting member having one end connected to the normal conducting conductor and the other end having a joint surface adjacent to the superconducting thin film;
A superconducting sheet for connection comprising a superconducting layer facing the superconducting thin film and the joining surface;
Along with joining the superconducting thin film and the superconducting layer of the connecting superconducting sheet, a conductive bonding material that joins the joining surface and the superconducting layer of the connecting superconducting sheet,
The terminal structure of a superconducting cable, wherein the normal conductive connecting member includes a through hole for introducing the conductive bonding material from an outer peripheral surface thereof to the bonding surface. In the superconducting conductor layer, a plurality of superconducting wires are laminated in the radial direction,
The end portion of the superconducting conductor layer is configured such that the end portion of the superconducting wire on the inner layer side is longer in the cable shaft end direction than the end portion of the superconducting wire on the outer layer side, and the superconducting thin film of each layer is configured in stages.
2. The terminal structure of a superconducting cable according to claim 1, wherein the joint surface is formed in a stepped manner so as to be adjacent to the superconducting thin film of each layer.   The superconducting cable terminal structure according to claim 1 or 2, wherein the superconducting layer of the superconducting sheet is made of the same material as the superconducting thin film of the superconducting wire.

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