JP2015141989A - Superconducting coil and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconducting coil having high operation stability and also to provide a method of manufacturing the same.SOLUTION: A method of manufacturing a superconducting coil includes: a prepreg forming step (S1) for obtaining a prepreg formed by coating a curing resin on fabric made of high intensity insulative filament having thermal conductivity or sheet body of nonwoven fabric, impregnating the coated curing resin thereinto, and semi-curing the impregnated curing resin; a raising step (S3) for raising the sheet body in the prepreg; a winding step (S4) for winding the prepreg together with a superconducting wire rod; and a curing step for curing the curing resin.

Description

  The present invention relates to a superconducting coil and a manufacturing method thereof, and more particularly to a superconducting coil having high operational stability and a manufacturing method thereof.

  Application of superconducting coils utilizing superconducting properties to various industrial machines is being studied. The superconducting coil is used in combination with a cooling system that winds a predetermined superconducting wire and cools the wire to a temperature that exhibits superconducting properties.

  For example, in Patent Document 1, a superconducting coil around which a superconducting wire is wound is laminated, a heat transfer plate is inserted in an intermediate portion thereof, and a heat absorber is attached to the surface of the superconducting coil. A superconducting coil and a cooling system for connecting an absorber to a refrigerator via a heat transporter are disclosed. Here, the wire of the superconducting coil is indirectly cooled by a refrigerator. Further, Patent Document 2 discloses a superconducting coil and a cooling system in which a superconducting coil is immersed in a refrigerant such as liquid helium filled in a container and the wire of the superconducting coil is brought into direct contact with the refrigerant to cool it. In such a cooling system, the refrigerant gas evaporated in the container is recovered outside, liquefied by a refrigerator, and then returned to the container again.

  Even if it is the superconducting coil of any type of patent document 1 or 2 which cools a superconducting wire directly or indirectly, it is necessary to wind this, insulating the superconducting wires. As a method of such insulation treatment, a method of winding a prepreg insulating material in a coil shape together with a superconducting wire and heat-treating the superconducting wire strongly in surface contact with each other, a method of winding a superconducting wire and injecting and hardening an insulating resin Etc. are known.

  For example, Patent Document 3 discloses that a paper-like insulator sheet mainly composed of inorganic fibers is wound with being superposed on a superconducting wire. Here, as a necessary characteristic in the insulator sheet that insulates the superconducting wires from each other, it is sufficiently thin while ensuring insulation performance, has flexibility to be wound with the superconducting wire, and it is necessary to fire the superconducting wire Describes that it is required to withstand heat treatment at 600 ° C. or higher after winding and not to react with the superconducting wire. Moreover, in patent document 4, as a prepreg insulating material which will give an insulator sheet, from a viewpoint of a low heat shrinkage rate, it is uncured epoxy resin, phenol resin, etc. to the woven fabric which consists of glass fiber, carbon fiber, and aramid fiber. A prepreg insulating material impregnated with a thermosetting resin is preferred.

  By the way, Non-Patent Document 1 discloses an epoxy resin-based FRP using a crystalline polymer having a high mechanical strength, insulating properties, and thermal conductivity and having a low thermal expansion coefficient as a reinforcing fiber. It is considered that such FRP is used for the above-described insulator sheet.

JP 2001-244109 A JP 2004-179443 A JP-A-8-222430 JP 2008-140900 A

Hiroki Kamijo, “Applying Super Fibers to Railways”, RRR (Technical Bulletin of Railway Technical Research Institute), Vol. 68, No. 11, November, 2011, pp. 6-9

  In order to ensure the operational stability of the superconducting coil, it is necessary to cool the superconducting wire to a predetermined temperature and maintain it. In addition, when the epoxy resin-based FRP using the crystalline polymer of Non-Patent Document 1 as a reinforcing fiber is used for the insulator sheet, the superconducting wire and the insulator sheet are secured so as to ensure the operational stability of the superconducting coil. It is also necessary to consider the reduction of the thermal stress generated in the process and the absorption of thermal fluctuations due to operating heat.

  This invention is made | formed in view of the above situations, The place made into the objective is to provide the superconducting coil which has high operation stability, and its manufacturing method.

  One of the methods for producing a superconducting coil according to the present invention is to obtain a prepreg in which a cured resin is applied and impregnated into a woven or non-woven sheet made of high-conductivity, high-strength insulating long fibers and semi-cured. It includes a prepreg forming step, a raising step for raising the sheet body in the prepreg, a winding step for winding the prepreg together with a superconducting wire, and a curing step for curing the curable resin.

  According to this invention, in the insulator obtained by curing the wound prepreg, in addition to the high thermal conductivity in the axial direction and the circumferential direction of the superconducting coil, good thermal conductivity can be imparted in the radial direction as well. When the wire is cooled, the operating heat can be favorably absorbed. Therefore, the thermal stress generated between the superconducting wire and the insulator can be reduced, and a superconducting coil having high operational stability can be provided.

  In the above-described invention, the raising step may be a step of raising a plurality of the prepregs so as to crosslink the sheet bodies with the high-strength insulating long fibers. According to this invention, the thickness of the insulator can be adjusted while improving the thermal conductivity in the radial direction of the obtained insulator, and the thermal stress generated between the superconducting wire and the insulator can be alleviated, resulting in high operational stability. A superconducting coil having the characteristics can be provided.

  In the above-described invention, the raising step may include a step of dispersing additional fibers made of the high-strength insulating long fibers therebetween when the prepregs are overlapped. According to this invention, it is possible to further improve the thermal conductivity in the thickness direction of the insulator obtained by curing the stacked prepregs, and to provide a superconducting coil having higher operational stability.

  Another method for producing a superconducting coil according to the present invention includes a raising step of raising a woven or non-woven sheet body made of heat conductive high-strength insulating continuous fibers, and applying a cured resin to the sheet body. It includes a prepreg forming step for obtaining a prepreg that has been impregnated and semi-cured, a winding step for winding the prepreg together with a superconducting wire, and a curing step for curing the cured resin.

  According to this invention, in the insulator obtained by curing the wound prepreg, in addition to the high thermal conductivity in the axial direction and the circumferential direction, it is possible to give good thermal conductivity in the radial direction, and the operation of the superconducting coil Heat absorption can be performed well. Therefore, the thermal stress generated between the superconducting wire and the insulator can be reduced, and a superconducting coil having high operational stability can be provided.

  In the above-described invention, the raising step may be a step of raising a plurality of the sheet bodies so as to crosslink them with the high-strength insulating long fibers. According to this invention, the thickness of the insulator can be adjusted while improving the thermal conductivity in the radial direction of the obtained insulator, and the thermal stress generated between the superconducting wire and the insulator can be alleviated, resulting in high operational stability. A superconducting coil having the characteristics can be provided.

  In the above-described invention, the raising step may include a step of dispersing additional fibers made of the high-strength insulating long fibers therebetween when the sheet bodies are overlapped. According to this invention, the thermal conductivity in the thickness direction of the insulator obtained from the stacked sheet bodies can be further improved, and a superconducting coil having higher operational stability can be provided.

  In the above-described invention, the raising step may be a step of raising and removing a needle so as to penetrate the sheet body. According to this invention, it is possible to provide a superconducting coil that can form good raising and has higher operational stability.

  The superconducting coil according to the present invention is manufactured by the above-described method for manufacturing a superconducting coil.

  According to such an invention, the thickness of the insulator can be adjusted while improving the thermal conductivity in the radial direction of the insulator that insulates the superconducting wire, and the thermal stress generated between the superconducting wire and the insulator can be relaxed, High operational stability can be obtained.

It is a perspective view of the superconducting coil by this invention. It is sectional drawing of the principal part of the superconducting coil manufactured by this invention. It is a top view of the woven fabric used for the superconducting coil by this invention. It is a flowchart which shows the manufacturing method by this invention. It is a perspective view of the prepreg laminated | stacked in the manufacturing method by this invention. It is sectional drawing of the laminated body of the prepreg in the manufacturing method by this invention. It is sectional drawing of the nonwoven fabric used for the superconducting coil by this invention. It is a flowchart which shows the other manufacturing method by this invention.

  The superconducting coil as one embodiment according to the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 1, the superconducting coil 40 is a so-called “coil 40” in which a composite wire 20 made of a strip-like body in which an insulating tape 11 is superimposed on a superconducting wire 10 is wound around an outer peripheral surface of a winding shaft 30 that is a hollow cylindrical body. It is a coil body called “pancake coil”. The winding shaft 30 is made of, for example, a metal such as stainless steel, ceramics, or FRP (Fiber Reinforced Plastics), and has a cylindrical shape in FIG. 1, but can take various shapes as necessary. For example, an yttrium-based superconductor can be used as the superconducting wire 10, but other known superconductors may be used.

  As shown in FIG. 2, the insulating tape 11 is a laminate in which layers are stacked in the thickness direction, and a composite resin body 9 in which a sheet body 5 made of fibers is sandwiched between cured resin portions 7 is formed as one layer unit. This is a fiber reinforced composite material laminate. In this embodiment, two layers of the composite resin body 9 are laminated, but this may be a single layer. The cured resin portion 7 is made of a thermosetting resin such as an epoxy resin or a polyester resin having a high insulating property.

  Referring also to FIG. 3, the sheet body 5 is made of high-strength insulating long fibers that have both high insulating properties and thermal conductivity, such as aramid fibers, polyethylene fibers, and PBO (polyparaphenylene benzobisoxazole) fibers. This is a woven fabric in which the long fiber bundles 4 are fixed in plain weave so as to be orthogonal to each other in the vertical and horizontal directions so as to be in thermal contact with each other at least. Here, the long fiber bundle 4 is plain-woven after being subjected to fiber-spreading treatment as necessary to form a strip. In addition, the long fiber bundle 4 may not be a strip | belt shape, but the cross-sectional shape may be circular or irregular shape, and the weave of the sheet | seat body 5 may be a twill weave or a satin weave, for example. Further, the warp yarn portion 2 and the weft yarn portion 3 may be made of different materials, thicknesses, etc., and the interval, the crossing angle of each other, etc. can be appropriately changed according to the mechanical strength required for the sheet body 5.

  Referring to FIG. 2 again, the additional fibers 8 are dispersedly arranged between the composite resin bodies 9 stacked and adjacent to each other. Similar to the long fiber bundle 4, the additional fiber 8 is a long fiber having insulating properties and high thermal conductivity, and is provided as a short fiber (chopped strand) obtained by cutting this short fiber.

  The long fiber bundle 4 of the warp yarn portion 2 and / or the weft yarn portion 3 has raised hairs 6 protruding from the surface thereof, and extends in a substantially vertical direction to the main surface of the composite resin body 9 inside the cured resin portion 7. Yes. The raising 6 is a linear body having a smaller diameter than the long fiber bundle 4. Each of the raised hairs 6 is in contact with or entangled with other raised hairs 6 extending from the surface of the long fiber bundle 4 included in the adjacent composite resin body 9, or the long fiber bundle included in the adjacent composite resin body 9 4, and the sheet bodies 5 in each composite resin body 9 are thermally cross-linked.

  Here, the sheet body 5 has high thermal conductivity in the direction along the main surface by the long fiber bundle 4 having high thermal conductivity of the warp yarn portion 2 and the weft yarn portion 3. Further, the sheet bodies 5 are thermally cross-linked through the long fiber bundle 4 and / or the raised hair 6 having high thermal conductivity. Therefore, the insulating tape 11 has high thermal conductivity not only in the direction along the main surface but also in the thickness direction. Moreover, the additional fiber 8 also has the raising | fluff 6, and can increase the density of thermal bridge | crosslinking similarly to above-mentioned.

[First manufacturing method]
Next, a method for manufacturing the above-described superconducting coil 40 will be described using FIG. 5 and FIG. 6 as appropriate along FIG.

  First, the sheet body 5 is impregnated with a thermosetting resin, and is dried by heating to obtain a thin plate-like prepreg 9 '(see FIG. 5) (S1: prepreg molding step). As will be described later, the prepreg 9 ′ is finally cured to give the composite resin body 9.

  Subsequently, as shown in FIG. 5, a plurality of prepregs 9 'are laminated as required (S2: lamination step). The number of prepregs 9 ′ to be laminated is determined by the thickness required for mechanical strength and insulation performance as the insulating tape 11. Therefore, a single prepreg 9 'may be used without being laminated. Further, if necessary, the additional fiber 8 is arranged to be dispersed on one main surface of the prepreg 9 ′, and the prepreg 9 ′ is overlapped with the additional fiber 8 interposed therebetween.

  Then, as shown in FIG. 6, the laminated body of the prepreg 9 'is needle punched to give the raised fibers 6 to the long fiber bundle 4 and / or the additional fibers 8 (S3: raising step). Here, the needle punch repeatedly gives a needle (needle) having minute protrusions in the thickness direction of the prepreg 9 ′, that is, the thickness direction of the sheet body 5, and repeatedly removes the long fiber bundle 4 and / or the additional fibers. The raised hair 6 is given by hooking 8. Thereby, as shown in FIG. 6 (b), FIG. 6 (b) shows a part of the long fiber bundle 4 and / or the additional fiber 8 as compared with FIG. It is possible to divide the prepreg 9 ′ to form the raised hairs 6 extending in the thickness direction that is the direction of the reciprocating movement of the needles, and to bridge the adjacent sheet bodies 5 with the raised hairs 6. Further, the direction of the additional fiber 8 can be changed in the thickness direction of the prepreg 9 ′ by needle punching, and both the adjacent sheet bodies 5 can be thermally cross-linked.

  Subsequently, the laminated body of the raised prepreg 9 'and the superconducting wire 10 are wound around the outer peripheral surface of the winding shaft 30 (S4: winding step). Finally, the wound prepreg 9 'is heat-treated to cure the resin 7' to form the insulating tape 11 made of the composite resin body 9 to obtain the superconducting coil 40 (S5: curing step).

  As described above, the insulating tape 11 according to the present embodiment raises the sheet body 5 made of the long fiber bundle 4 having high thermal conductivity in the thickness direction, and in addition to the direction along the main surface, also in the thickness direction. High thermal conductivity is given. That is, the superconducting coil 40 in which the insulating tape 11 and the superconducting wire 10 are wound has high thermal conductivity in the axial direction and the circumferential direction, and also has good thermal conductivity in the radial direction. Therefore, the operating heat of the coil is absorbed well, the thermal stress generated between the superconducting wire 10 and the insulating tape 11 is reduced, and high operating stability is given. Moreover, according to the long fiber bundle 4 with a small thermal expansion coefficient, a dimensional change is small with respect to the heat history at the time of use of the superconducting coil 40, and high operation stability will be given.

  Here, since the insulating tape 11 has high insulating properties, the thickness thereof can be reduced, and the thermal conductivity in the thickness direction can be improved. On the other hand, even if the thickness is increased to increase the mechanical strength of the insulating tape, the thermal conductivity in the thickness direction is not impaired. That is, the operation stability of the superconducting coil 40 is maintained without depending on the thickness of the insulating tape 11.

  In the above-described embodiment, a woven fabric is used for the sheet body 5. However, as shown in FIG. 7, a nonwoven fabric in which fibers 14 are accumulated and fixed in a felt shape may be used. Similar to the long fiber bundle 4, the fibers 14 are made of high-strength insulating long fibers having insulating properties and high thermal conductivity. Specifically, referring to FIG. 7, the fibers 14 are arranged along the virtual plane P <b> 1 while being tangled at random inside the sheet body 5 ′. With such a structure, the amount of the raised hair 6 formed for imparting a predetermined thermal conductivity can be relatively reduced, and the working time in the raising step S3 can be reduced.

[Second manufacturing method]
Next, another method for manufacturing the superconducting coil 40 will be described with reference to FIG.

  First, the sheet body 5 made of woven fabric is laminated as necessary (S11: lamination step). The number of sheet bodies 5 to be laminated is determined by the mechanical strength and the insulating performance required for the insulating tape 11, and may be a single sheet body 5 without being laminated. Further, if necessary, the additional fibers 8 may be arranged on one main surface of the sheet body 5 so as to be dispersed, and the sheet body 5 may be overlapped with the additional fibers 8 interposed therebetween.

  Subsequently, the laminated sheet body 5 is needle punched to give the raised fibers 6 to the long fiber bundle 4 and / or the additional fibers 8 (S12: raised step). The raising step S12 is the same as the raising step S3 described in the first manufacturing method. When the additional fiber 8 is inserted, the sheet body 5 does not include the resin 7 ′, and the additional fiber 8 can be erected in the thickness direction of the sheet body 5 to promote cross-linking between the sheet bodies 5, and in the thickness direction. Thermal conductivity can be easily improved.

  Subsequently, the laminated and raised sheet body 5 is impregnated with a thermosetting resin and dried by heating to obtain a semi-cured prepreg 9 ′ (see FIG. 6B) (S13: prepreg forming step). ). Further, the prepreg 9 ′ and the superconducting wire 10 are wound around the outer peripheral surface of the winding shaft 30 so as to overlap (S 14: winding step). Finally, the wound prepreg 9 'is heat-treated to cure the resin 7' to form the insulating tape 11 made of the composite resin body 9, and to obtain the superconducting coil 40 (S15: curing step).

  Also by this manufacturing method, similarly to the first manufacturing method, the thermal stress generated between the superconducting wire 10 and the insulating tape 11 can be reduced, and the superconducting coil 40 having high operational stability can be obtained. In particular, the nap 6 is formed prior to the impregnation of the thermosetting resin into the sheet body 5, and the amount of the nap 6 can be increased relatively easily, so that the thermal conductivity in the thickness direction between the sheet bodies 5 can be easily achieved. Can be adjusted.

  Similar to the first manufacturing method, a non-woven fabric (see FIG. 7) in which fibers 14 are accumulated and fixed instead of a woven fabric may be used as the sheet body 5 ′.

  Up to this point, representative embodiments and modifications based thereon have been described. However, the present invention is not necessarily limited thereto, and those skilled in the art will understand the gist of the present invention or the appended claims. Various alternative embodiments and modifications may be found without departing from the invention. For example, the composite wire 20 may be wound around the outer peripheral surface of the winding shaft 30 after making the periphery of the superconducting wire 10 covered with the insulating tape 11.

4 Long fiber bundle 5 Sheet body 6 Brushed 7 Cured resin portion 7 'Resin 8 Additional fiber 9 Composite resin body 9' Prepreg 10 Superconducting wire 11 Insulating tape 30 Spindle 40 Superconducting coil

Claims (8)

A method of manufacturing a superconducting coil, comprising:
A prepreg forming step for obtaining a prepreg obtained by semi-curing a cured resin by applying and impregnating a cured resin to a woven fabric or a nonwoven fabric sheet composed of thermally conductive high-strength insulating long fibers;
A raising step for raising the sheet body in the prepreg;
A winding step of winding the prepreg together with the superconducting wire;
And a curing step for curing the cured resin.   The method for producing a superconducting coil according to claim 1, wherein the raising step is a step of raising a plurality of the prepregs so that the sheet bodies are bridged with the high-strength insulating long fibers. .   3. The method of manufacturing a superconducting coil according to claim 2, wherein the raising step includes a step of dispersing additional fibers made of the high-strength insulating long fibers between the prepregs. A method of manufacturing a superconducting coil, comprising:
A raising step for raising a woven or non-woven sheet made of thermally conductive high-strength insulating long fibers;
A prepreg forming step of obtaining a prepreg obtained by applying and impregnating a cured resin to the sheet body and semi-curing it;
A winding step of winding the prepreg together with the superconducting wire;
And a curing step for curing the cured resin.   5. The method of manufacturing a superconducting coil according to claim 4, wherein the raising step is a step of raising a plurality of the sheet bodies so as to be bridged with the high-strength insulating long fibers.   6. The method of manufacturing a superconducting coil according to claim 5, wherein the raising step includes a step of dispersing additional fibers made of the high-strength insulating long fibers therebetween when the sheet bodies are overlapped.   The method of manufacturing a superconducting coil according to claim 1, wherein the raising step is a step of raising and removing a needle so as to penetrate the sheet body.   A superconducting coil manufactured by a manufacturing method according to any one of claims 1 to 7.

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