JP2014212173A - Superconducting coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconducting coil which inhibits the damage from being generated in a tape type superconductive wire.SOLUTION: A superconducting coil includes: a tape type superconductive wire 50 wound around a reel 20; an electrode 40 which is fixed to the reel 20 and to which the end of the tape type superconductive wire 50 is connected; and a filler 60 arranged between the tape type superconductive wires 50. A non-arrangement part 70 is provided in which the filler 60 is not arranged from one electrode 40 toward the other electrode 40.

Description

  The present invention relates to a superconducting coil using a tape-type superconducting wire.

  In recent years, as a superconducting wire used for a superconducting coil, a tape-shaped superconducting wire (referred to as a tape-type superconducting wire) made of a high-temperature superconducting wire has been used. This tape-type superconducting wire is used by being wound into, for example, a pancake.

  The wound tape-type superconducting wire is joined to electrodes for external connection at both ends thereof. This electrode is fixed to a winding frame around which the tape type superconducting wire is wound.

  When the superconducting coil is in operation, the tape type superconducting wire is cooled in order to realize a superconducting state. In order to increase the cooling efficiency at the time of cooling, a filler is filled and solidified in a gap between wound tape-type superconducting wires (Patent Document 1).

JP 2008-305861 A

  The tape-type superconducting wire and filler perform thermal shrinkage when cooled. However, the thermal contraction rate of the tape type superconducting wire is different from the thermal contraction rate of the filler. Moreover, the electrodes joined to both ends of the tape-type superconducting wire are mechanically fixed to a winding frame or the like.

  For this reason, when the tape-type superconducting wire is cooled, stress concentration may occur in the tape-type superconducting wire due to the difference in the thermal shrinkage rate.

  One of the exemplary purposes of an aspect of the present invention is to provide a superconducting coil that suppresses the occurrence of stress concentration in a tape-type superconducting wire.

According to one aspect of the invention,
A tape-type superconducting wire wound around a winding frame;
An electrode that is fixed to the reel and to which an end of the superconducting wire is connected;
A superconducting coil having a filler disposed between the tape-type superconducting wires,
A configuration is provided in which a non-arrangement portion in which the filler is not arranged is provided from one electrode to another electrode.

  According to an aspect of the present invention, it is possible to prevent stress concentration from occurring in the tape-type superconducting wire due to the difference in thermal shrinkage between the tape-type superconducting wire and the filler.

FIG. 1 shows a superconducting coil according to an embodiment, wherein (A) is a plan view, (B) is a front view, and (C) is a side view. FIG. 2 is an enlarged plan view showing the vicinity of an electrode of a superconducting coil according to an embodiment. FIG. 3 is an enlarged schematic configuration diagram showing a tape-type superconducting wire near the electrodes of a superconducting coil according to an embodiment. FIG. 4 is a diagram for explaining Lorentz force acting on a tape-type superconducting wire in the vicinity of an electrode of a superconducting coil according to an embodiment. FIG. 5 is an enlarged schematic configuration diagram showing a tape-type superconducting wire near the electrodes of a superconducting coil according to another embodiment. FIG. 6 is an enlarged schematic configuration diagram showing a tape-type superconducting wire near the electrodes of a superconducting coil as a reference example.

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

  1 and 2 show a superconducting coil 10 according to an embodiment of the present invention. The superconducting coil 10 includes a winding frame 20, a coil body 30, an electrode 40, a non-arrangement portion 70, and the like.

  The reel 20 has a winding core 21, an upper flange 22, and a lower flange 23. The winding frame 20 is made of a nonmagnetic material, and can be integrally formed with a resin, for example. In addition, the winding frame 20 can also be set as the structure which forms separately the winding core 21, the upper flange 22, and the lower flange 23, and joins these.

  The winding core 21 becomes a winding center when a tape-type superconducting wire 50 described later is wound. The upper flange 22 is provided on the upper part of the winding core 21. The lower flange 23 is provided at the lower part of the core 21.

  The upper flange 22 and the lower flange 23 have the same diameter, and are set larger than the diameter of the core 21. For this reason, the winding frame 20 has a bobbin-like shape as a whole.

  The coil main body 30 has a plurality (four in this embodiment) of coil winding bodies 32A to 32D. The coil winding bodies 32 </ b> A to 32 </ b> D are stacked coaxially on the core 21 of the winding frame 20 in the vertical direction (directions indicated by arrows Z <b> 1 and Z <b> 2 in FIG. 1B). Moreover, each coil winding body 32A-32D winds the tape type superconducting wire 50 in the shape of a pancake.

  For the tape-type superconducting wire 50, for example, an RE-123 oxide superconductor (REBa2Cu3O7-X: RE is a rare earth element) can be used. The tape-type superconducting wire 50 is obtained by forming a superconducting material such as an RE-123 oxide superconductor on a tape-shaped base material.

  Further, in order for the tape type superconducting wire 50 to realize a superconducting state, the superconducting coil 10 is cooled by a refrigerator (not shown) (for example, Gifford McMahon refrigerator). In order to increase the cooling efficiency at the time of cooling, when the tape-type superconducting wire 50 is wound around the winding frame 20, the filler 60 is filled between the wound tape-type superconducting wire 50 and solidified. (See the right end of FIG. 3).

  Therefore, each of the coil winding bodies 32A to 32D is in a state where the tape-type superconducting wire 50 and the filler 60 are alternately laminated in a plan view.

  The filler 60 is preferably a material excellent in thermal conductivity, insulation, etc. at low temperatures. For example, an epoxy resin can be used as the filler 60. Since the filler 60 also has a function equivalent to an adhesive, when the filler 60 is disposed between the laminated tape type superconducting wires 50, the laminated tape type superconducting wire 50 is separated by the filler 60. It becomes a fixed state.

  Moreover, each of the coil winding bodies 32A to 32D is electrically connected. And the electrode 40 for externally connecting the superconducting coil 10 is joined to the both ends of these connected coil winding bodies 32A-32D.

  The electrode 40 includes an electrode main body 41, a fixing portion 42, and a wire joint portion 43. This electrode 40 can be formed of copper having good conductivity, for example. In particular, it is desirable to use high-purity oxygen-free copper having good electrical characteristics. It should be noted that a conductive material other than copper can be used as the material of the electrode 40.

  The electrode 40 is fixed to the upper flange 22 of the winding frame 20. The electrode 40 has a fixing portion 42 that extends to the side of the electrode main body 41. The fixing portion 42 has an insertion hole through which the fixing bolt 47 is inserted. A bolt hole to which the fixing bolt 47 is fastened is formed at a position corresponding to the insertion hole of the upper flange 22.

  The electrode 40 is fixed to the upper flange 22 by inserting the fixing bolt 47 through the insertion hole and fixing it to the bolt hole. In a state where the electrode 40 is fixed to the upper flange 22, the electrode main body 41 is erected upward from the upper flange 22.

  Thus, since the electrode 40 is fixed to the winding frame 20 using the fixing bolt 47, the electrode 40 is not displaced relative to the winding frame 20 in the fixed state.

  As described above, both ends of the tape-type superconducting wire 50 are joined to the electrode 40 and electrically connected thereto. A wire joint portion 43 is formed below the electrode 40.

  The end of the tape-type superconducting wire 50 is joined to the wire joint 43 using a joining method such as soldering. In this joined state, the end portion of the tape-type superconducting wire 50 is electrically connected to the wire joint 43 and mechanically fixed. Therefore, no displacement occurs between the end of the tape-type superconducting wire 50 and the wire joint 43 at the joining position.

  Here, attention is paid to the vicinity where the electrode 40 and the tape-type superconducting wire 50 are joined.

  FIG. 3 is an enlarged schematic configuration diagram showing a portion indicated by a broken line indicated by an arrow A in FIG. As described above, when the tape-type superconducting wire 50 is wound around the winding frame 20, the filler 60 is filled in the portion where the tape-type superconducting wire 50 is laminated (overlaid).

  However, in the present embodiment, a region where the filler 60 is not disposed is provided between the opposing tape-type superconducting wires 50 (hereinafter, the region where the filler 60 is not disposed is referred to as a non-arranged portion 70. Called). As shown in FIGS. 2 and 3, the non-arranged portion 70 is formed from an electrode 40 joined to one end of the tape type superconducting wire 50 to an electrode 40 joined to the other end of the tape type superconducting wire 50. Toward the direction (in the direction indicated by the arrow X2 in FIGS. 2 and 3).

  The formation range (indicated by arrow L1 in FIG. 3) of the non-arranged portion 70 is such that the tape-type superconducting wire 50 in the joining range (indicated by arrow L2 in FIG. 3) in which the electrode 40 is joined to the tape-type superconducting wire 50 is used. From the position of the end on the extending side (the position indicated by the arrow P1 in FIG. 3; hereinafter referred to as the boundary position P1), the position of the end where the filler 60 is disposed (the position indicated by the arrow P2 in FIG. 3). Hereinafter referred to as the arrangement end position P2.

  In the formation range of the non-arrangement portion 70, as shown in FIGS. 2 and 3, a gap portion 71 is formed between the opposing tape-type superconducting wires 50, or a pair of opposing ones (not shown). The tape type superconducting wire 50 comes into contact.

  This non-arrangement part 70 is formed by not arranging the filler 60 over the range of the non-arrangement part 70 when the tape-type superconducting wire 50 is wound, for example, in the manufacturing process of the coil body 30. Can do. Further, by applying a release agent in a range corresponding to the non-arrangement part 70 in advance, the filler 60 in a range corresponding to the non-arrangement part 70 is removed after the tape-type superconducting wire 50 is wound. Is also possible.

  It is not always necessary to remove the filler 60 in the range corresponding to the non-arranged portion 70. When a release agent is disposed, the release agent is interposed between the non-arrangement part 70 and the filler 60. The release agent does not fix the tape-type superconducting wire 50 laminated with the filler 60, so that the filler 60 is substantially disposed even if the filler is interposed in the non-arrangement portion 70. Equivalent to no state. Moreover, you may interpose the filler which does not have a function as an adhesive agent between tape-type superconducting wires 50. In this way, a region equivalent to a state where the filler 60 is not substantially disposed is also referred to as a non-arranged portion 70.

  As described above, in order for the superconducting coil 10 to function, the tape-type superconducting wire 50 needs to be in a superconducting state, and therefore the superconducting coil 10 is cooled by a refrigerator (not shown).

  By performing a cooling process on the coil main body 30 (tape superconducting wire 50) by the refrigerator, the filler 60 disposed between the stacked tape superconducting wires 50 is also cooled. As described above, the filler 60 is a resin such as an epoxy resin, and the tape-type superconducting wire 50 includes the superconducting material.

  Therefore, the thermal contraction rate (thermal linear expansion coefficient) of the tape-type superconducting wire 50 and the thermal contraction rate (thermal linear expansion coefficient) of the filler 60 are different. That is, there is a difference between the shrinkage (indicated by black arrows in the figure) generated in the tape-type superconducting wire 50 when cooled and the shrinkage (indicated by white arrows) in the filler 60. To do.

  For this reason, as described above, there is a possibility that stress is generated between the tape-type superconducting wire 50 and the filler 60 due to a difference in thermal contraction when the cooling is performed.

  The electrode 40 is mechanically and firmly fixed to the winding frame 20 (upper flange 22) using a fixing bolt 47. Therefore, as in the reference example shown in FIG. 6, when the filler 60 is disposed in the entire range of the tape-type superconducting wire 50 without providing the non-arranged portion 70, stress concentration occurs at the disposed end position P. It is likely to occur.

  On the other hand, in this embodiment, the non-arrangement part 70 in which the filler 60 is not arranged is formed in a predetermined range from the boundary position P1 to the arrangement end position P2. This non-arranged portion 70 can reduce or eliminate the generation of stress due to the difference in thermal shrinkage between the tape-type superconducting wire 50 and the filler 60 because the filler 60 does not exist.

  In particular, in the present embodiment, the non-arrangement part 70 is provided in a region including the boundary position P1 where stress concentration is likely to occur. For this reason, it is possible to effectively prevent the tape-type superconducting wire 50 from being damaged due to the stress concentration.

  Next, the position and length (indicated by the arrow L1 in FIG. 3) of the non-arrangement part 70 will be described.

  Since the non-arrangement portion 70 reduces the generation of stress due to the difference in thermal shrinkage between the tape-type superconducting wire 50 and the filler 60 as described above, the non-arrangement portion 70 includes the boundary position P1 where stress concentration is likely to occur. It is preferable.

  In addition, as shown in FIG. 5, even if a filler 60 is disposed at a lower position of the electrode 40 (this filler 60 is particularly referred to as an under-electrode filler 60a), the length of the under-electrode filler 60a is short. Further, at the position immediately below the electrode 40, the thermal contraction of the tape-type superconducting wire 50 and the filler 60 is regulated by the electrode 40 that is firmly fixed to the upper flange 22. For this reason, it is not always necessary to provide the non-arrangement part 70 at the lower position of the electrode 40.

  Therefore, it is preferable to form the non-arrangement part 70 at least in the direction (the direction indicated by the arrow X2 in FIG. 3) toward the other electrode from the boundary position P1.

  Further, it is desirable to set the length L1 of the non-arranged portion 70 to be long in order to suppress the generation of the thermal stress. However, Lorentz force is applied to the tape-type superconducting wire 50 constituting the superconducting coil 10 from a magnetic field.

  This Lorentz force is applied in a direction orthogonal to the extending direction of the tape-type superconducting wire 50 as indicated by an arrow F in FIG. In a region other than the non-arranged portion 70 where the filler 60 is disposed, the tape-type superconducting wire 50 having a lower mechanical strength than the filler 60 is held by the filler 60. Therefore, the tape type superconducting wire 50 is not damaged by the Lorentz force.

  However, in the non-arrangement portion 70, this Lorentz force is received only by the tape-type superconducting wire 50. Therefore, the range of the non-arranged portion 70 is preferably set to a range where the tape-type superconducting wire 50 is not affected by the Lorentz force.

  Therefore, in this embodiment, the range of the non-arrangement part 70 includes at least the boundary position P1, and is set to an area where the tape-type superconducting wire 50 in the non-arrangement part 70 is not damaged by the Lorentz force.

  By providing the non-arranged portion 70 set in this way, the tape-type superconducting wire 50 is damaged due to the stress concentration caused by the thermal contraction difference between the tape-type superconducting wire 50 and the filler 60, and the Lorentz force. Any damage to the tape-type superconducting wire 50 can be prevented, and a highly reliable superconducting coil 10 can be realized.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments described above, and various modifications are possible within the scope of the gist of the present invention described in the claims. Variations and changes are possible.

DESCRIPTION OF SYMBOLS 10 Superconducting coil 20 Winding frame 21 Core 22 Upper flange 23 Lower flange 30 Coil main body 32A-32D Coil winding body 40 Electrode 41 Electrode main body 42 Fixing part 43 Wire material joining part 45 Electrode holder 47 Fixing bolt 50 Tape type superconducting wire 60 Filling Material 60a Under-electrode filler 70 Non-placement portion 71 Gap portion 72 Gap portion under electrode

Claims (3)

A tape-type superconducting wire wound around a winding frame;
An electrode that is fixed to the reel and to which an end of the tape-type superconducting wire is connected;
A superconducting coil having a filler disposed between the tape-type superconducting wires,
A superconducting coil, wherein a non-arrangement part in which the filler is not arranged is provided from one electrode to another electrode.   2. The superconducting coil according to claim 1, wherein the non-arranged portion includes a boundary between the one electrode and the tape-type superconducting wire in the extending direction of the tape-type superconducting wire.   The superconducting coil according to claim 1, wherein the non-arranged portion is a space formed between the tape-type superconducting wires.

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