Superconducting coil

Abstract

A superconducting coil has a superconducting wire (3), an insulating sheet (4), and an adhesive resin (5). The insulating sheet (4) includes a plurality of resin sheets and two sheets of semi-cured resin fiber sheet (7). The plurality of resin sheets have electrical insulation and are laminated with at least two or more layers. The two sheets of semi-cured resin fiber sheet (7) are laminated in a manner that the plurality of resin sheets are sandwiched between each other. In the plurality of resin sheets and the two sheets of semi-cured resin fiber sheet (7), the resin sheets and the semi-cured resin fiber sheet (7) that are adjacent to each other are engaged with each other.

Description

Technical Field

[0001] This disclosure relates to superconducting coils. Background Technology

[0002] As a prior art document disclosing the structure of a superconducting coil, there is Japanese Patent No. 4607540 (Patent Document 1). The superconducting coil described in Patent Document 1 includes a superconducting wire, an insulating sheet, and an adhesive resin. The insulating sheet has been treated with an easy-to-adhere finish on its surface.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 4607540 Summary of the Invention

[0006] The problem to be solved by the present invention

[0007] During the cooling of the superconducting coil, cooling stress is generated due to the difference in thermal shrinkage between the adhesive resin and the insulating sheet. During the excitation of the superconducting coil, electromagnetic stress is generated. Due to this cooling stress or electromagnetic stress, if the interface between the adhesive resin and the insulating sheet cracks and peels, generating heat, heat is transferred to the superconducting wire, potentially causing quenching.

[0008] This disclosure was made to solve the above-mentioned problems, and its purpose is to provide a superconducting coil capable of suppressing the generation of quench.

[0009] Problem-solving methods

[0010] The superconducting coil based on this disclosure comprises a superconducting wire, an insulating sheet, and an adhesive resin. The superconducting wire is wound in multiple turns and multiple layers. The insulating sheet is arranged in multiple turns of the superconducting wire between the layers. The adhesive resin fills the space between the superconducting wire and the insulating sheet. The insulating sheet comprises multiple resin sheets and two semi-cured resin fiber sheets. The multiple resin sheets are electrically insulating and are stacked in at least two layers. The two semi-cured resin fiber sheets are stacked in such a way that the multiple resin sheets are sandwiched between each other. In the multiple resin sheets and the two semi-cured resin fiber sheets, adjacent resin sheets and semi-cured resin fiber sheets are bonded to each other.

[0011] The effects of the invention

[0012] According to this disclosure, in the insulating sheet, two semi-cured resin fiber sheets are stacked in such a way that multiple resin sheets are sandwiched between each other, and adjacent resin sheets and semi-cured resin fiber sheets are bonded to each other. As a result, peeling and cracking at the interface between the adhesive resin and the insulating sheet can be suppressed, and heat is difficult to be transferred to the superconducting wire, thereby suppressing the generation of quench. Attached Figure Description

[0013] Figure 1 This is a longitudinal sectional view showing the structure of the superconducting coil in Embodiment 1.

[0014] Figure 2 This is a longitudinal cross-sectional view showing the structure of the insulating sheet by magnifying the interlayer of the superconducting wire in the superconducting coil of Embodiment 1.

[0015] Figure 3 This is a longitudinal cross-sectional view showing the structure of the insulating sheet by magnifying the interlayer of the superconducting wire in the superconducting coil of Embodiment 2.

[0016] Figure 4 This is a longitudinal cross-sectional view showing the structure of the insulating sheet by magnifying the interlayer of the superconducting wire in the superconducting coil of Embodiment 3.

[0017] Figure 5 This is a longitudinal cross-sectional view showing the structure of the insulating sheet by magnifying the interlayer of the superconducting wire in the superconducting coil of Embodiment 4. Detailed Implementation

[0018] Hereinafter, the superconducting coils of various embodiments will be described with reference to the accompanying drawings. In the following description of the embodiments, the same or equivalent parts in the drawings will be labeled with the same reference numerals, and their descriptions will not be repeated.

[0019] The DR1 direction shown in each figure is parallel to the axial direction of the superconducting coil. The DR2 direction is perpendicular to the axial direction of the superconducting coil.

[0020] Implementation Method 1

[0021] Figure 1 This is a longitudinal sectional view showing the structure of the superconducting coil in Embodiment 1. Figure 2 This is a longitudinal cross-sectional view showing the structure of the insulating sheet by magnifying the interlayer of the superconducting wire in the superconducting coil of Embodiment 1.

[0022] like Figure 1 and Figure 2 As shown, the superconducting coil 1 comprises a winding frame 2, a superconducting wire 3, an insulating sheet 4, and an adhesive resin 5. The winding frame 2 is a cylindrical body with flanges at both ends. The winding frame 2 is made of materials such as stainless steel.

[0023] The superconducting wire 3 is wound in multiple turns along the DR1 direction and in multiple layers along the DR2 direction relative to the outer periphery of the cylinder excluding the flange portion of the winding frame 2. The superconducting wire 3 is made of materials such as NbTi and Nb3Sn. An insulating coating is applied to the surface of the superconducting wire 3.

[0024] The insulating sheet 4 is arranged in multiple turns between the layers of the superconducting wire 3. The insulating sheet 4 is also arranged in multiple turns between the roll frame 2 and the superconducting wire 3.

[0025] An adhesive resin 5, such as epoxy resin, is filled between the superconducting wire 3 and the insulating sheet 4. The superconducting wire 3 is bonded to each other and the superconducting wire 3 and the insulating sheet 4 are bonded to each other through the adhesive resin 5.

[0026] The insulating sheet 4 comprises multiple resin sheets and two semi-cured resin fiber sheets 7. The multiple resin sheets are electrically insulating and are stacked in at least two layers. The two semi-cured resin fiber sheets 7 are stacked in such a way that the multiple resin sheets are sandwiched between each other.

[0027] In this embodiment, the plurality of resin sheets are two plastic sheets 6. That is, the plurality of resin sheets include plastic sheets 6. However, the resin sheets are not limited to plastic sheets. In addition, the number of resin sheets is not limited to two, but may be three or more.

[0028] As described above, in this embodiment, the insulating sheet 4 includes: two stacked plastic sheets 6; and two semi-cured resin fiber sheets 7, which are stacked in such a way that the two plastic sheets 6 are sandwiched between each other. The two semi-cured resin fiber sheets 7 constitute the outer surface layers of both sides of the insulating sheet 4.

[0029] The plastic sheet 6 is made of, for example, polyester or polyethylene terephthalate. The thickness of one plastic sheet 6 is, for example, tens to hundreds of μm.

[0030] The semi-cured resin fiber sheet 7 is formed by semi-curing epoxy resin impregnated with glass cloth or kraft paper with a thickness of about tens to hundreds of μm.

[0031] In the two plastic sheets 6 and the two semi-cured resin fiber sheets 7, the adjacent plastic sheets 6 and semi-cured resin fiber sheets 7 are joined together using a known joining method.

[0032] The stacked and adjacent plastic sheets 6 are joined together only at their ends in the axial direction (DR1 direction) of the superconducting coil 1. In this embodiment, the adjacent plastic sheets 6 and the semi-cured resin fiber sheet 7 are joined together by an adhesive. Therefore, as Figure 2 As shown, the plastic sheets 6 are joined together by adhesive portions 8 located at the ends of the superconducting coil 1 in the spool direction (DR1 direction).

[0033] The stacked and adjacent plastic sheets 6 are coated with a fluoropolymer resin at their overlapping and contact portions. The fluoropolymer resin is, for example, Teflon (a registered trademark). Furthermore, the fluoropolymer resin is not applied to the portions coated with adhesive.

[0034] The manufacturing method of the superconducting coil 1 according to Embodiment 1 will be described below. An insulating sheet 4 is wound around the outer periphery of the cylinder of the winding frame 2, excluding the flange portion. The ends of the superconducting coil 1 formed by the overlapping plastic sheets 6 constituting the insulating sheet 4 are joined together in the axial direction (DR1 direction) by an adhesive portion 8. Furthermore, the semi-cured resin fiber sheet 7 located on the inner periphery of the insulating sheet 4 in contact with the winding frame 2 may be omitted.

[0035] The superconducting wire 3 is wound in multiple turns and multiple layers around the outer periphery of the insulating sheet 4 wound around the winding frame 2. At this time, the insulating sheet 4 is placed between each layer of the superconducting wire 3. Then, adhesive resin 5 is filled into the gap between the superconducting wire 3 and the insulating sheet 4 by vacuum impregnation or the like, and then cured. Simultaneously with the curing of the adhesive resin 5, the semi-cured resin fiber sheet 7 is fully cured, and the semi-cured resin fiber sheet 7 and the adhesive resin 5 are bonded together. As a result, the insulating sheet 4 and the adhesive resin 5 are firmly bonded together.

[0036] In the superconducting coil 1 of this embodiment 1, two semi-cured resin fiber sheets 7 are laminated in the insulating sheet 4 by sandwiching two plastic sheets 6 between each other, which can firmly bond the insulating sheet 4 and the adhesive resin 5, thus suppressing peeling and cracking at the interface between the insulating sheet 4 and the adhesive resin 5. Even when heat is generated due to friction between the plastic sheets 6, the semi-cured resin fiber sheets 7 sandwiched between the superconducting wire 3 and the plastic sheets 6 make it difficult for heat to be transferred to the superconducting wire 3, thus suppressing the generation of quench loss.

[0037] The stacked and adjacent plastic sheets 6 are joined only at their ends in the axial direction (DR1 direction) of the superconducting coil 1, thereby preventing the adhesive resin 5 from entering between the plastic sheets 6. As a result, the adhesion between the plastic sheets 6 and each other by the adhesive resin 5 is suppressed, and the adhesive strength between the plastic sheets 6 is maintained at a low level. Therefore, when cooling stress or electromagnetic stress is applied to the superconducting coil 1 and strain is generated within the superconducting coil 1, the plastic sheets 6 can easily peel off from each other and release the strain, thus suppressing the accumulation of large strain energy within the superconducting coil 1. Furthermore, it is possible to suppress the accumulation of strain energy from being released as heat and causing quenching.

[0038] By coating the areas where the plastic sheets 6 are stacked and in contact with each other with fluororesin, even when the adhesive resin 5 is inserted between the plastic sheets 6, the adhesive strength between the plastic sheets 6 can be maintained at a low level due to the presence of fluororesin between the plastic sheets 6 and the adhesive resin 5. Therefore, when cooling stress or electromagnetic stress acts on the superconducting coil 1 and strain is generated within the superconducting coil 1, the plastic sheets 6 can easily peel off from each other and release the strain, thus suppressing the accumulation of large strain energy within the superconducting coil 1. Furthermore, it is possible to suppress the accumulation of strain energy from being released as heat and causing quenching.

[0039] In the superconducting coil 1 of this embodiment 1, by using an insulating sheet 4 with a prepreg sheet attached, the superconducting coil 1 can be manufactured without complex processes such as welding the insulating sheet 4 and the adhesive resin 5, thus reducing the manufacturing cost of the superconducting coil 1.

[0040] Implementation Method 2

[0041] The superconducting coil of Embodiment 2 will be described below. The superconducting coil of Embodiment 2 differs from the superconducting coil 1 of Embodiment 1 only in that the resin sheet is made of cured resin fiber sheet, so the same structure as the superconducting coil 1 of Embodiment 1 will not be described again.

[0042] Figure 3 This is a longitudinal cross-sectional view showing the structure of the insulating sheet by magnifying the interlayer of the superconducting wire in the superconducting coil of Embodiment 2. In this embodiment, the plurality of resin sheets are two cured resin fiber sheets 9. That is, the plurality of resin sheets include cured resin fiber sheets 9. However, the resin sheets are not limited to cured resin fiber sheets. In addition, the number of resin sheets is not limited to two sheets, but may be three or more sheets.

[0043] As described above, in this embodiment, the insulating sheet 4 includes: two laminated cured resin fiber sheets 9; and two semi-cured resin fiber sheets 7, which are laminated in such a way that the two cured resin fiber sheets 9 are sandwiched between each other.

[0044] The cured resin fiber sheet 9 is formed by completely curing epoxy resin, which is impregnated with glass cloth or kraft paper and has a thickness of about tens to hundreds of μm.

[0045] In two cured resin fiber sheets 9 and two semi-cured resin fiber sheets 7, adjacent cured resin fiber sheets 9 and semi-cured resin fiber sheets 7 are joined together using a known joining method.

[0046] The stacked and adjacent cured resin fiber sheets 9 are joined together only at their ends in the axial direction (DR1 direction) of the superconducting coil. In this embodiment, the adjacent cured resin fiber sheets 9 and semi-cured resin fiber sheets 7 are joined together by an adhesive. Therefore, as Figure 3 As shown, the cured resin fiber sheets 9 are joined together by adhesive portions 8 at the ends located in the spool direction (DR1 direction) of the superconducting coil.

[0047] In the superconducting coil of this embodiment 2, two semi-cured resin fiber sheets 7 are stacked in the insulating sheet 4, with two cured resin fiber sheets 9 sandwiched between them. This allows the insulating sheet 4 and the adhesive resin 5 to be firmly bonded, thus suppressing peeling and cracking at the interface between the insulating sheet 4 and the adhesive resin 5. Even when heat is generated due to friction between the cured resin fiber sheets 9, the presence of semi-cured resin fiber sheets 7 sandwiched between the superconducting wire 3 and the cured resin fiber sheets 9 makes it difficult for heat to be transferred to the superconducting wire 3, thereby suppressing quench loss.

[0048] The stacked and adjacent cured resin fiber sheets 9 are joined only at their ends in the axial direction (DR1 direction) of the superconducting coil, thereby preventing the adhesive resin 5 from entering between the cured resin fiber sheets 9. As a result, the adhesion of the cured resin fiber sheets 9 to each other through the adhesive resin 5 is suppressed, and the adhesive strength between the cured resin fiber sheets 9 is maintained at a low level. Therefore, when cooling stress or electromagnetic stress acts on the superconducting coil and strain is generated within the superconducting coil, the cured resin fiber sheets 9 can easily peel off from each other and release the strain, thus suppressing the accumulation of large strain energy within the superconducting coil. Furthermore, it is possible to suppress the accumulation of strain energy from being released as heat and causing quenching.

[0049] By ensuring complete curing of the resin in the cured resin fiber sheets 9, even when the adhesive resin 5 is incorporated between the cured resin fiber sheets 9, the bond strength between the cured resin fiber sheets 9 can be maintained at a low level. Therefore, when cooling stress or electromagnetic stress acts on the superconducting coil and strain is generated within the superconducting coil, the cured resin fiber sheets 9 can easily peel off from each other and release the strain, thus suppressing the accumulation of large strain energy within the superconducting coil. Furthermore, it can prevent the accumulated strain energy from being released as heat and causing quenching.

[0050] Implementation Method 3

[0051] The superconducting coil of Embodiment 3 will be described below. The main difference between the superconducting coil of Embodiment 3 and the superconducting coil 1 of Embodiment 1 is that the plurality of resin sheets also include release sheets. Therefore, the same structure as the superconducting coil 1 of Embodiment 1 will not be described again.

[0052] Figure 4 This is a longitudinal cross-sectional view showing the structure of the insulating sheet by magnifying the interlayer of the superconducting wire in the superconducting coil of Embodiment 3. In this embodiment, the plurality of resin sheets also include release sheets 10. Specifically, the plurality of resin sheets are composed of one plastic sheet 6 and two release sheets 10. However, the number of release sheets 10 is not limited to two; it can also be one.

[0053] As described above, in this embodiment, the insulating sheet 4 includes: one plastic sheet 6; two release sheets 10, stacked to sandwich the plastic sheet 6 between each other; and two semi-cured resin fiber sheets 7, stacked to sandwich the two release sheets 10 between each other. That is, the two release sheets 10 are adjacent to a corresponding semi-cured resin fiber sheet 7 of the two semi-cured resin fiber sheets 7. The two semi-cured resin fiber sheets 7 constitute the outer surface layers of both sides of the insulating sheet 4.

[0054] The material of the release sheet 10 is, for example, fluoropolymer. Fluoropolymer, for example, is Teflon (a registered trademark). The thickness of the release sheet 10 is, for example, tens of μm.

[0055] like Figure 4 As shown, the width of the release sheet 10 in the spool direction (DR1 direction) of the superconducting coil is narrower than the width of the plastic sheet 6 and the two semi-cured resin fiber sheets 7.

[0056] Thus, when the plastic sheet 6 and the semi-cured resin fiber sheet 7, which are stacked in a manner that clamps the release sheet 10 to each other, are cured by the adhesive resin 5, they are joined together only at the ends of the superconducting coil in the spool direction (DR1 direction) by the adhesive resin 5.

[0057] In the superconducting coil of this embodiment 3, since a release sheet 10 is disposed adjacent to the plastic sheet 6, the adhesive strength between the plastic sheet 6 and the release sheet 10 can be maintained at a low level. Therefore, when cooling stress or electromagnetic stress acts on the superconducting coil and strain is generated within the superconducting coil, the plastic sheet 6 and the release sheet 10 can easily peel off from each other to release the strain, thus suppressing the accumulation of large strain energy within the superconducting coil. Furthermore, it can suppress the accumulation of strain energy from being released as heat and causing quenching.

[0058] By making the width of the release sheet 10 in the spool direction (DR1 direction) of the superconducting coil narrower than the width of the plastic sheet 6 and the two semi-cured resin fiber sheets 7, the plastic sheet 6 and the semi-cured resin fiber sheets 7, which are stacked in a manner that clamps the release sheet 10 between each other, can be bonded together with adhesive resin 5 only at the end of the superconducting coil in the spool direction (DR1 direction).

[0059] Implementation Method 4

[0060] The superconducting coil of Embodiment 4 will be described below. The main difference between the superconducting coil of Embodiment 4 and the superconducting coil of Embodiment 2 is that the multiple resin sheets also include release sheets. Therefore, the structure that is the same as that of the superconducting coil of Embodiment 2 will not be described again.

[0061] Figure 5This is a longitudinal cross-sectional view showing the structure of the insulating sheet by magnifying the interlayer of the superconducting wire in the superconducting coil of Embodiment 4. In this embodiment, the plurality of resin sheets also include release sheets 10. Specifically, the plurality of resin sheets are composed of one cured resin fiber sheet 9 and two release sheets 10. However, the number of release sheets 10 is not limited to two; it may also be one.

[0062] As described above, in this embodiment, the insulating sheet 4 includes: one cured resin fiber sheet 9; two release sheets 10 stacked together to hold the cured resin fiber sheet 9 between each other; and two semi-cured resin fiber sheets 7 stacked together to hold the two release sheets 10 between each other. That is, the two release sheets 10 are adjacent to a corresponding semi-cured resin fiber sheet 7 of the two semi-cured resin fiber sheets 7. The two semi-cured resin fiber sheets 7 constitute the outer surface layers of both sides of the insulating sheet 4.

[0063] like Figure 5 As shown, the width of the release sheet 10 in the spool direction (DR1 direction) of the superconducting coil is narrower than the width of the cured resin fiber sheet 9 and the two semi-cured resin fiber sheets 7.

[0064] Thus, when the plastic sheet 6 and the semi-cured resin fiber sheet 7, which are stacked in a manner that clamps the release sheet 10 to each other, are cured by the adhesive resin 5, they are joined together only at the ends of the superconducting coil in the spool direction (DR1 direction) by the adhesive resin 5.

[0065] In the superconducting coil of this embodiment 4, a release sheet 10 is disposed adjacent to the cured resin fiber sheet 9, thus maintaining a low bond strength between the cured resin fiber sheet 9 and the release sheet 10. Consequently, when cooling stress or electromagnetic stress acts on the superconducting coil and strain is generated within the superconducting coil, the cured resin fiber sheet 9 and the release sheet 10 can easily peel off from each other to release the strain, thereby suppressing the accumulation of large strain energy within the superconducting coil. Furthermore, it is possible to suppress the accumulation of strain energy from being released as heat and causing quenching.

[0066] The width of the release sheet 10 in the spool direction (DR1 direction) of the superconducting coil is narrower than the width of the cured resin fiber sheet 9 and the two semi-cured resin fiber sheets 7, thereby enabling the cured resin fiber sheets 9 and semi-cured resin fiber sheets 7, which are stacked together in a manner that clamps the release sheet 10, to be joined together by the adhesive resin 5 only at the end of the superconducting coil in the spool direction (DR1 direction).

[0067] Furthermore, the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of this disclosure should not be interpreted solely by the above embodiments. Additionally, all modifications within the scope and equivalent to the claims are included. In the description of the above embodiments, composable structures may also be combined with each other.

[0068] Explanation of reference numerals in the attached figures

[0069] 1. Superconducting coil, 2. Roll frame, 3. Superconducting wire, 4. Insulating sheet, 5. Adhesive resin, 6. Plastic sheet, 7. Semi-cured resin fiber sheet, 8. Adhesive part, 9. Cured resin fiber sheet, 10. Release sheet.

Claims

1. A superconducting coil, wherein, Possessing: a superconducting wire, wound throughout a plurality of turns and a plurality of layers; an insulating sheet, disposed between layers of the superconducting wire, throughout the plurality of turns of the superconducting wire; and an adhesive resin, filled between the superconducting wire and the insulating sheet and cured, the insulating sheet including: a resin sheet, having electrical insulating properties; two release sheets, laminated in a manner to sandwich the resin sheet between each other; and two semi-cured resin fiber sheets, laminated in a manner to sandwich the two release sheets between each other, the two semi-cured resin fiber sheets being substantially cured while the adhesive resin is cured, the adhesive resin and the two semi-cured resin fiber sheets being adhered to each other, in the resin sheet and the two semi-cured resin fiber sheets, resin sheets and semi-cured resin fiber sheets that are adjacent to each other are engaged to each other. The resin sheet includes a plastic sheet.

2. The superconducting coil of claim 1, wherein, The resin sheet includes a cured resin fiber sheet.

3. The superconducting coil of claim 1, wherein, The resin sheet and the semi-cured resin fiber sheet, laminated in a manner to sandwich the two release sheets, are engaged only at end portions in a winding axis direction of the superconducting coil.

4. The superconducting coil of claim 1, wherein, The two release sheets each have a width in the winding axis direction of the superconducting coil that is narrower than a width of each of the resin sheet and the semi-cured resin fiber sheet, which are engaged only at the end portions.

5. The superconducting coil of claim 4, wherein, ​

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