Superconducting coil

Abstract

To provide a superconducting coil that can easily improve its performance such as insulating characteristics.SOLUTION: A superconducting coil of an embodiment comprises a winding member in which a superconducting wire is wound around a winding axis. The superconducting wire has a superconducting wire body part, and an insulating coating layer formed of an insulating material so as to cover the surface of the superconducting wire body part. The insulating coating layer is formed on the surface of the superconducting wire body part so as to include at least a portion interposed between the turns of the superconducting wire.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to a superconducting coil. [Background technology]

[0002] Superconducting devices that have been put to practical use include magnetic resonance imaging (MRI) devices, superconducting magnetic energy storage (SMES) devices, and single crystal pulling devices. Superconducting devices are equipped with superconducting coils that include winding members around which superconducting wire is wound.

[0003] When fabricating winding members for a superconducting coil, for example, high-temperature superconducting wire, which has excellent critical current characteristics at high temperatures and in a strong magnetic field, is used as the superconducting wire. The high-temperature superconducting wire is a tape wire with a multilayer structure, which includes a laminate in which multiple layers such as an intermediate layer, a superconducting layer, and a protective layer are stacked on a metal substrate, and the periphery of the laminate is covered with a stabilizing layer.

[0004] When radial stress is applied to a winding member made of superconducting wire with a multilayer structure, the stress acts on the superconducting wire with a multilayer structure as a peeling force, which may cause delamination in the superconducting wire. When delamination occurs in the superconducting wire, the superconducting characteristics of the superconducting coil may deteriorate. For example, when the superconducting coil is cooled to an operating temperature, a difference in thermal contraction rate occurs between the resin filled between the turns and the superconducting wire, and this difference in thermal contraction rate may cause a peeling force to be applied, which may cause delamination.

[0005] To solve this problem, it has been proposed to fabricate a winding member by co-winding the superconducting wire and a co-winding material such as a polyimide film, and to bond side plates to the side surfaces of the winding member along the radial direction of the winding central axis. In this case, the superconducting wire and the co-winding material such as a polyimide film are not bonded and can be separated, so the peeling force applied in the stacking direction is absorbed, and delamination is prevented. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5534712 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the past, when a superconducting wire and a co-winding material such as a polyimide film were wound together, the co-winding material could become misaligned. Furthermore, the co-winding material could become misaligned during operation of the superconducting coil. As a result, the insulation characteristics between the turns of the superconducting wire could become insufficient, which could result in a deterioration in the performance of the superconducting coil.

[0008] Therefore, the problem to be solved by the present invention is to provide a superconducting coil that can easily improve performance such as insulation characteristics. [Means for solving the problem]

[0009] A superconducting coil according to an embodiment includes a winding member in which a superconducting wire is wound around a winding center axis. The superconducting wire has a superconducting wire main body and an insulating coating layer formed of an insulating material so as to cover the surface of the superconducting wire main body. The insulating coating layer is formed on the surface of the superconducting wire main body so as to include at least a portion interposed between turns of the superconducting wire. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view schematically showing a partially exploded view of a superconducting coil 10 according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing the superconducting coil 10 according to the first embodiment. [Figure 3] FIG. 3 is a partially exploded perspective view of superconducting wire main body 200 in the embodiment. [Figure 4] FIG. 4 is a flow diagram showing an example of a method for manufacturing the superconducting coil 10 according to the first embodiment. [Figure 5] FIG. 5 is a perspective view schematically showing a partially exploded view of superconducting coil 10 according to the second embodiment. [Figure 6] FIG. 6 is a cross-sectional view schematically showing a superconducting coil 10 according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] First Embodiment [A] Overview of superconducting coil 10 FIG. 1 is a perspective view schematically showing a partially exploded view of a superconducting coil 10 according to the first embodiment.

[0012] In this embodiment, the superconducting coil 10 has a winding member 12 and a side plate 14, as shown in FIG.

[0013] [A-1] Winding member 12 The winding member 12 has, for example, a pancake shape, and is produced by winding the superconducting wire 20 around the bobbin 11.

[0014] In this embodiment, the reel 11 has a cylindrical shape having a central winding axis AX (central axis).

[0015] The superconducting wire 20 is a tape wire, and is wound concentrically in a circumferential direction CD around the spool 11. That is, the superconducting wire 20 is wound around a winding central axis AX, and the superconducting wire 20 is stacked by a plurality of turns in a radial direction RD of the winding central axis AX.

[0016] [A-2] Side plate 14 The side plates 14 are installed on the side surfaces of the winding member 12 along the radial direction RD of the winding center axis AX in order to maintain the shape of the winding member 12. The side plates 14 are, for example, ring-shaped plate bodies, and are coaxial with the winding member 12. The side plates 14 are made of an insulating material such as glass fiber reinforced plastic (GFRP).

[0017] A cooling plate (not shown) for conducting cooling of the superconducting coil 10 may be provided on the superconducting coil 10.

[0018] [B] Details of superconducting coil 10 FIG. 2 is a cross-sectional view schematically showing the superconducting coil 10 according to the first embodiment.

[0019] Fig. 2 shows a portion of Fig. 1 taken along a cross section (e.g., an xz plane) of the winding central axis AX. In Fig. 2, the vertical direction (z) corresponds to the axial direction of the winding central axis AX, the horizontal direction (x) corresponds to the radial direction RD of the winding central axis AX, the left side being the inner circumferential side IN, and the right side being the outer circumferential side OT. In Fig. 2, the direction (y) perpendicular to the paper surface corresponds to the tangential direction of the circumferential direction (winding direction) of the winding central axis AX.

[0020] [B-1] Superconducting wire 20 In this embodiment, as shown in FIG. 2, a tape wire (high-temperature superconducting wire) having an insulating coating layer 210 provided on a superconducting wire main body 200 is used as the superconducting wire 20.

[0021] In superconducting wire 20, superconducting wire main body 200 has a rectangular cross section. When superconducting wire main body 200 is wound into winding member 12, first main body surface S201 is located on inner periphery side IN in radial direction RD, and second main body surface S202 is located on outer periphery side OT in radial direction RD.

[0022] In the superconducting wire 20, the insulating coating layer 210 coats the first main body surface S201 and the second main body surface S202. The insulating coating layer 210 is formed on the surface of the superconducting wire main body 200 so as to include portions interposed between the turns of the superconducting wire 20 constituting the winding member 12. At the same time, the insulating coating layer 210 also coats portions of the surface of the superconducting wire main body 200 other than the first main body surface S201 and the second main body surface S202. That is, in the superconducting wire 20 of this embodiment, the entire periphery of the superconducting wire main body 200 is coated with the insulating coating layer 210. In this embodiment, the winding member 12 includes portions where the insulating coating layers 210 coating the superconducting wire main body 200 contact each other between the turns of the superconducting wire 20.

[0023] In the superconducting wire 20, the insulating coating layer 210 is formed of an insulating material. The insulating material constituting the insulating coating layer 210 is a resin such as polyvinyl formal, polyvinyl butyral, polyester, polyurethane, polyamide, polyamideimide, or polyimide, and a mixture of multiple resins may also be used. The insulating coating layer 210 covers the periphery of the superconducting wire main body 200 with a uniform thickness.

[0024] In the winding member 12 of this embodiment, the turns of the superconducting wire main body 200 of the Nth turn and the superconducting wire main body 200 of the (N+1)th turn located adjacent thereto are electrically insulated by an insulating coating layer 210.

[0025] The superconducting wire main body 200 will be further described in detail.

[0026] Fig. 3 is a partially exploded perspective view of the superconducting wire main body 200 in the first embodiment. Fig. 3 schematically shows the state before winding is performed.

[0027] As shown in FIG. 3, superconducting wire main body 200 has a multilayer structure including, for example, metal substrate 201, orientation layer 202, intermediate layer 203, superconducting layer 204, protective layer 205, and stabilizing layer 206.

[0028] The metal substrate 201 is in the form of a tape and is made of a high-strength metal material such as stainless steel or a nickel alloy such as Hastelloy (registered trademark).

[0029] The alignment layer 202 is laminated on the surface of the metal substrate 201. The alignment layer 202 is made of a material such as magnesium oxide, and is provided to orient the intermediate layer 203.

[0030] Intermediate layer 203 is laminated on the surface of metal substrate 201 with orientation layer 202 interposed therebetween. Intermediate layer 203 is made of a material such as cerium oxide, magnesium oxide, yttrium oxide, or ytterbium oxide. Intermediate layer 203 functions as a buffer layer that alleviates thermal distortion that occurs between metal substrate 201 and superconducting layer 204 due to thermal contraction.

[0031] Superconducting layer 204 is laminated on the surface of metal substrate 201, with orientation layer 202 and intermediate layer 203 interposed in that order. Superconducting layer 204 is made of a Re123-based high-temperature superconductor (RE-based oxide superconducting wire material) such as YBCO, DyBCO, or GdBCO.

[0032] Protective layer 205 is laminated on the surface of metal substrate 201 with orientation layer 202, intermediate layer 203, and superconducting layer 204 interposed in that order. Protective layer 205 is made of a material such as silver. Protective layer 205 is provided for the purpose of preventing superconducting layer 204 from being deteriorated due to contact with moisture in the air. Protective layer 205 functions as a bypass path for current commutation when excessive electricity flows in superconducting layer 204.

[0033] Stabilization layer 206 covers the periphery of the laminate of metal substrate 201, orientation layer 202, intermediate layer 203, superconducting layer 204, and protective layer 205. Stabilization layer 206 is made of a conductive material such as copper or silver. Like protective layer 205, stabilization layer 206 functions as a bypass path for commutating current when excessive electricity flows in superconducting layer 204.

[0034] In superconducting wire main body 200, orientation layer 202 and protective layer 205 may be omitted as appropriate depending on the required properties.

[0035] [B-2] Side plate 14 2, side plate 14 is adhered to the side surface of winding member 12 via adhesive resin layer 141. Adhesive resin layer 141 is formed of an adhesive material such as epoxy resin. In this embodiment, adhesive resin layer 141 is not filled between the turns of superconducting wire 20 that constitutes winding member 12.

[0036] [C] Manufacturing method of superconducting coil 10 FIG. 4 is a flow diagram showing an example of a method for manufacturing the superconducting coil 10 according to the first embodiment.

[0037] 4, in the winding member fabrication process, a winding step (ST11) and a heat treatment step (ST12) are performed in sequence to fabricate the winding member 12. In this embodiment, the winding member 12 is fabricated without resin impregnation.

[0038] [C-1] Winding process (ST11) In the winding step (ST11), superconducting wire 20 is wound around bobbin 11 to produce winding member 12 in, for example, a pancake shape (see FIG. 1).

[0039] [C-2] Heat treatment process (ST12) In the heat treatment process (ST12), for example, a side plate 14 is placed on the side of the winding member 12 (see Figure 2) around which the superconducting wire 20 is wound, along the radial direction RD of the winding center axis AX, and then heat treatment is performed (see Figures 1 and 2).

[0040] The side plate 14 is a prepreg coated with an adhesive resin layer 141 on one side, and the side plate 14 is installed on the winding member 12 so that the surface of the side plate 14 coated with the adhesive resin layer 141 faces the side of the winding member 12.

[0041] Then, heat treatment is performed to melt the adhesive resin layer 141 provided on the side plate 14. The melted adhesive resin layer 141 fills the gap between the winding member 12 and the side plate 14. As a result, the winding member 12 and the side plate 14 are bonded together, thereby producing the winding member 12. If the adhesive resin layer 141 is a thermosetting resin, the thermosetting resin is hardened by the heat treatment. Note that the heat treatment step (ST12) may be performed after the winding step (ST11) is performed with the side plate 14 placed on the reel 11.

[0042] [D] Summary As described above, the superconducting coil 10 of this embodiment includes the winding member 12 in which the superconducting wire 20 is wound around the winding center axis AX. The superconducting wire 20 has an insulating coating layer 210 formed of an insulating material so as to cover the surface of the superconducting wire main body 200. The insulating coating layer 210 is formed on the surface of the superconducting wire main body 200 so as to include the portion interposed between the turns of the superconducting wire 20.

[0043] Therefore, in the superconducting coil 10 of this embodiment, even if the superconducting wire is misaligned during winding or operation of the superconducting coil 10, the insulating coating layer 210 is provided on the surface of the superconducting wire 20, so that it is possible to prevent a deterioration in the insulating properties between turns of the superconducting wire.

[0044] Furthermore, in the winding member 12 of this embodiment, adhesive resin layers 141 are not filled between the turns of the superconducting wire 20, and the turns of the superconducting wire 20 include portions where the insulating coating layers 210 coating the superconducting wire main body 200 contact each other. That is, in the superconducting coil 10, the superconducting wire 20 can be separated between the turns. Therefore, in this embodiment, no peeling force is applied to the superconducting wire 20. Therefore, in this embodiment, it is possible to effectively prevent peeling from occurring in the superconducting wire 20, which has a multilayer structure, and therefore it is possible to suppress deterioration of the superconducting properties. Note that although adhesive resin layers 141 are not provided between the turns, there is a possibility that resin will seep out onto the upper and lower end faces between the turns when the adhesive resin layer 141 is melted.

[0045] Second Embodiment [A] Configuration of superconducting coil 10 Fig. 5 is a perspective view schematically showing a partially exploded state of the superconducting coil 10 according to the second embodiment. Fig. 6 is a cross-sectional view schematically showing the superconducting coil 10 according to the second embodiment.

[0046] As shown in Figures 5 and 6, in this embodiment, superconducting coil 10 has winding members 12 and side plates 14, similar to the first embodiment (see Figures 1 and 2). However, superconducting coil 10 of this embodiment differs from the first embodiment in that part of the configuration of winding members 12. Except for this point and related points, this embodiment is similar to the first embodiment. Therefore, explanations of overlapping points will be omitted where appropriate.

[0047] In this embodiment, the winding member 12 has a common winding material 30, as shown in FIGS. 5 and 6, unlike the first embodiment.

[0048] The co-winding wire material 30 is made of, for example, a resin material. The resin material that makes up the co-winding wire material 30 is polyimide, polyethylene terephthalate (PET), aramid resin, or the like, and has insulating properties. In addition to the above, the co-winding wire material 30 may also be made of a conductive metal material if insulating properties are not required.

[0049] The winding member 12 of this embodiment is produced by winding the superconducting wire 20 and the co-winding wire 30 around the bobbin 11. That is, the superconducting wire 20 and the co-winding wire 30 are wound together around the winding center axis AX, and multiple turns of the superconducting wire 20 and the co-winding wire 30 are alternately stacked in the radial direction RD of the winding center axis AX.

[0050] The winding member 12 of this embodiment includes a portion where the common winding material 30 and the insulating coating layer 210 contact each other between the turns of the superconducting wire 20. Specifically, the first prepreg base material surface S301 located on the inner circumferential side IN in the radial direction RD of the common winding material 30 contacts the insulating coating layer 210 that covers the second main body surface S202 of the superconducting wire main body 200 that constitutes the superconducting wire 20. The second prepreg base material surface S302 located on the outer circumferential side OT in the radial direction RD of the common winding material 30 contacts the insulating coating layer 210 that covers the first main body surface S201 of the superconducting wire main body 200 that constitutes the superconducting wire 20.

[0051] In this embodiment, the coefficient of friction of the surfaces (S301, S302) of the co-winding wire material 30 that come into contact with the insulating coating layer 210 is smaller than the coefficient of friction of the surfaces of the insulating coating layer 210 that come into contact with the co-winding wire material 30. In other words, the coefficient of friction of the first prepreg base material surface S301 of the co-winding wire material 30 is smaller than the coefficient of friction of the surface of the insulating coating layer 210 that covers the second main body surface S202 of the superconducting wire main body 200. The coefficient of friction of the second prepreg base material surface S302 of the co-winding wire material 30 is smaller than the coefficient of friction of the surface of the insulating coating layer 210 that covers the first main body surface S201 of the superconducting wire main body 200. The co-winding wire material 30 may be a tape wire whose surface is coated with, for example, a fluororesin so that the surface coefficient of friction is smaller than that of the insulating coating layer 210.

[0052] [B] Summary The internal stress distribution of the superconducting coil 10 repeatedly changes due to heat cycles, excitation / demagnetization, vibration, and the like. This can cause wear due to friction between turns of the superconducting coil 10, resulting in a deterioration of the insulating properties between the turns. However, in this embodiment, the friction coefficient of the surface of the co-winding wire material 30 that contacts the insulating coating layer 210 is smaller than the friction coefficient of the surface of the insulating coating layer 210 that contacts the co-winding wire material 30. Therefore, in the superconducting coil 10 of this embodiment, the insulating coating layer 210 that covers the surface of the superconducting wire main body 200 is less susceptible to wear than in the first embodiment. Therefore, this embodiment can more effectively prevent the insulating properties between the turns from deteriorating.

[0053] <Other> Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0054] 10: superconducting coil, 11: winding frame, 12: winding member, 14: side plate, 20: superconducting wire, 30: co-winding wire, 141: adhesive resin layer, 200: superconducting wire main body, 201: metal substrate, 202: orientation layer, 203: intermediate layer, 204: superconducting layer, 205: protective layer, 206: stabilizing layer, 210: insulating coating layer,

Claims

1. A superconducting coil including a winding member in which a superconducting wire is wound around a winding center axis, The superconducting wire is a superconducting wire main body; an insulating coating layer formed of an insulating material so as to cover the surface of the superconducting wire body; and the insulating coating layer is formed on the surface of the superconducting wire body so as to include at least a portion interposed between turns of the superconducting wire; Superconducting coil.

2. The winding member is Co-wound wire material that is co-wound with the superconducting wire material and includes a portion where the common winding material and the insulating coating layer contact each other between turns of the superconducting wire, a friction coefficient of a surface of the co-winding material that contacts the insulating coating layer is smaller than a friction coefficient of a surface of the insulating coating layer that contacts the co-winding material; 2. The superconducting coil according to claim 1.

3. a side plate provided on a side surface of the winding member along the radial direction RD of the winding central axis Equipped with 2. The superconducting coil according to claim 1.

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