Superconducting coil

Abstract

To provide a superconducting coil which winds both a superconducting wire rod and a reinforcement material, and forms an insulation resin layer by impregnation curing, and improves a space factor.SOLUTION: A superconducting coil includes a winding drum, a winding part for winding a superconducting wire rod and a reinforcement material around the winding drum, and an insulation resin layer obtained by impregnation curing the winding part, wherein at least a part of the reinforcement material is fixed to the winding drum.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] Embodiments of the present invention relate to superconducting coils.

Background Art

[0002] A superconducting coil using a high-temperature superconducting wire represented by a REBCO wire containing rare earth can generate a strong magnetic field in a small volume as compared with a superconducting coil using a low-temperature superconducting wire.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An electromagnetic force is generated in a superconducting wire by a self-magnetic field or an external magnetic field. In order to share the hoop stress in the longitudinal direction of the superconducting wire generated by this electromagnetic force, a reinforcing material may be co-wound around the superconducting wire. Also, an insulating resin layer may be formed for insulation between turns of the superconducting wire. When the insulating resin layer is formed by impregnation curing, the insulating resin layer may be formed thick, and the occupancy rate of the superconducting coil may decrease.

[0005] Therefore, the problem to be solved by the present invention is to provide a superconducting coil in which a superconducting wire and a reinforcing material are co-wound, an insulating resin layer is formed by impregnation curing, and the occupancy rate is improved.

Means for Solving the Problems

[0006] To solve the above problems, the superconducting coil of the embodiment comprises a winding drum, a winding section in which superconducting wire and reinforcing material are wound around the winding drum, and an insulating resin layer impregnated and cured over the winding section, wherein at least a portion of the reinforcing material has a fixing member separate from the insulating resin layer between the reinforcing material and the winding drum. The winding frame that constitutes the winding drum It is positioned, and this fixing member The end of the reinforcing material is on the surface of the winding frame It is characterized by being fixed in place. [Brief explanation of the drawing]

[0007] [Figure 1] A perspective view showing an example of the configuration of a superconducting coil according to the first embodiment. [Figure 2] A plan cross-sectional view showing an example of the winding drum configuration according to the first embodiment. [Figure 3] A cross-sectional view showing the radial cross-section of the coil along the line II-II in Figure 1. [Figure 4] Cross-sectional view of section A in Figure 3. [Figure 5] A perspective view showing an example of the configuration of a superconducting wire according to the first embodiment. [Figure 6] A cross-sectional view of the starting point of the winding section in a superconducting coil according to the first embodiment. [Figure 7] A schematic plan view showing a method for manufacturing a superconducting coil according to the first embodiment. [Figure 8] A cross-sectional view of the winding start of the winding portion in a superconducting coil according to a modified example of the first embodiment. [Figure 9] A cross-sectional view of the winding start of the winding portion in a superconducting coil according to a modified example of the first embodiment. [Figure 10] A cross-sectional view of the winding start of the winding portion in a superconducting coil according to a modified example of the first embodiment. [Figure 11] A cross-sectional view of the winding start of the winding portion in a superconducting coil according to a modified example of the first embodiment. [Modes for carrying out the invention]

[0008] The following describes embodiments for carrying out the invention. (First Embodiment)

[0009] The first embodiment will be described with reference to Figures 1 to 7. Figure 1 is a perspective view showing an example of the configuration of the superconducting coil 1, Figure 2 is a plan cross-sectional view showing an example of the configuration of the winding drum 10, Figure 3 is a cross-sectional view showing a radial cross-section of the coil along the line II-II in Figure 1, Figure 4 is a cross-sectional view of part A in Figure 3, Figure 5 is a perspective view showing an example of the configuration of the superconducting wire 22, Figure 6 is a cross-sectional view of the beginning of the winding of the winding portion 20 in the superconducting coil 1, and Figure 7 is a schematic plan cross-sectional view showing the manufacturing method of the superconducting coil 1. Note that in Figures 1 to 7, the same components are denoted by the same reference numerals, and some explanations of their components are omitted.

[0010] As shown in Figure 1, in the first embodiment, the superconducting coil 1 comprises a winding drum 10 and a winding section 20, and is a pancake coil in which a space is formed at the center of the winding axis by winding the winding section 20 onto the winding drum 10. The direction parallel to the winding axis of the superconducting coil 1 is called the winding axis direction, the direction in which the winding section 20 is wound is called the circumferential direction, and the direction in which the winding section 20 is stacked by winding is called the radial direction. In the following description, a single pancake superconducting coil 1 is used as an example, but its type is not limited to that, and for example, a solenoid coil or a double pancake coil may also be used.

[0011] As shown in Figure 2, the winding drum 10 comprises a winding frame 12 and a coil electrode 14, and is provided on the inner circumference side of the winding section 20, which will be described later, to maintain the shape of the winding section 20. Although Figure 2 shows a circular example of the winding drum 10, it may also be elliptical, oblong, rectangular, or the like, and its shape is not limited.

[0012] The winding frame 12 is made of, for example, glass-reinforced plastic, PTFE (pretetrafluoroethylene), or a metal material. The coil electrode 14 is made of, for example, a metal with low electrical resistance such as copper or silver, and is electrically connected to the superconducting wire 22, thereby allowing current to flow into the superconducting coil 1.

[0013] Note that the volume ratio between the winding frame 12 and the coil electrode 14 in the drum 10 can be set arbitrarily. When the electrode is not required, it may all be the winding frame 12. When it is desired to reduce the electrical resistance value of the coil electrode 14, etc., it may all be the coil electrode 14. Further, the winding frame 12 and the coil electrode 14 are fixed by, for example, an adhesive or the like.

[0014] As shown in FIGS. 3 and 4, the winding portion 20 includes a superconducting wire 22, a reinforcing material 24, an inter-turn insulating material 26, an insulating resin layer 28, and a side insulating material 30, and is provided on the outer peripheral side of the drum 10. The winding portion 20 is formed by winding the superconducting wire 22, the reinforcing material 24, and the inter-turn insulating material 26 on the outer peripheral side of the drum 10. Details of the formation of the winding portion 20 will be described later.

[0015] As shown in FIG. 5, the superconducting wire 22 includes a substrate 32, an intermediate layer 34, an alignment layer 33, a superconducting layer 35, a protective layer 36, and a stabilization layer 31. The start of winding of the superconducting wire 22 is fixed to the coil electrode 14 by soldering or the like, as shown in FIG. 6.

[0016] The substrate 32 is formed of a material such as a high-strength metal such as a nickel-based alloy, stainless steel, or copper.

[0017] The intermediate layer 34 is a diffusion prevention layer and is formed of a material such as cerium doped, YSZ, magnesium oxide, yttrium oxide, ytterbium oxide, barium zirconia, etc. on the substrate 32.

[0018] The alignment layer 33 is provided for the purpose of aligning the intermediate layer 34 on the substrate 32 and is formed of magnesium oxide or the like. When an aligned substrate 32 is used, the alignment layer 33 may not be provided.

[0019] The superconducting layer 35 consists of a superconducting thin film having, for example, an RE123 system composition (RE1B2C3O7, etc.). In "RE1B2C3O7", "RE" represents at least one of the rare earth elements (e.g., neodymium (Nd), gadolinium (Gd), holmium (Ho), samarium (Sm), etc.) and yttrium, "B" represents barium (Ba), "C" represents copper (Cu), and "O" represents oxygen (O).

[0020] The protective layer 36 is provided to prevent the superconducting layer 35 from deteriorating due to contact with moisture in the air, and is made of silver or the like. The protective layer 36 also serves to prevent the superconducting layer 35 from burning if an excessive current flows through it.

[0021] The stabilization layer 31 is provided to prevent the superconducting layer 35 from burning by acting as a bypass path for the current when an excessive current flows through it, and is formed from, for example, conductive copper or silver.

[0022] The width w of the multi-layered superconducting wire 22 is, for example, 4 to 12 mm, and the thickness t is, for example, 0.1 to 0.2 mm.

[0023] The superconducting wire 22 is not limited to the above configuration, and the type and number of each layer may be changed as needed.

[0024] The reinforcing material 24 is preferably made of a material with a higher Young's modulus and yield stress than the superconducting wire 22, and is formed from, for example, stainless steel or a nickel-based alloy. The reinforcing material 24 is formed to be bendable as a coil, and its width is, for example, about the same as that of the superconducting wire 22. The thickness of the reinforcing material 24 is designed such that the stress generated in the superconducting wire 22 due to hoop stress is less than or equal to the allowable stress of the superconducting wire 22, and is, for example, 0.1 to 0.5 mm. Multiple reinforcing materials 24 may be stacked and arranged.

[0025] As shown in Figure 6, the starting point of the reinforcing material 24 is mechanically fixed to a part of the outer diameter surface of the winding drum 10. The reinforcing material 24 may be fixed to the winding frame 12 or to the coil electrode 14 of the winding drum 10. The reinforcing material 24 is fixed to the winding drum 10 using a fixing member 40 separate from the insulating resin layer 28, which will be described later. The fixing member 40 may be used to fix the reinforcing material 24 to the winding drum 10 by means of adhesive, adhesive tape, welding, soldering, or brazing. The reinforcing material 24 reduces the hoop stress acting on the superconducting wire 22 by sharing a portion of the hoop stress, which will be described later, with the superconducting wire 22, thereby preventing deterioration of the superconducting properties.

[0026] The inter-turn insulating material 26 is an insulating tape formed from, for example, an insulating film such as polyimide, polyester, polyurethane, polyamide, polyimidoamide, polyvinyl formal, or polyvinyl butyral, or from a fiber-reinforced plastic such as glass fiber reinforced plastic (GFRP), carbon fiber reinforced plastic (CFRP), or glass cloth impregnated with a thermosetting resin (epoxy resin, phenolic resin, urea resin, melamine resin, etc.). The inter-turn insulating material 26 is wound around the turns of the superconducting wire 22 to insulate the adjacent turns of the superconducting wire 22.

[0027] The insulating resin layer 28 is an adhesive insulating material such as epoxy resin, phenolic resin, urea resin, or melamine resin. The insulating resin layer 28 not only insulates the turns of the superconducting wire 22 by impregnating and curing it with the resin when winding at least a portion of the winding section 20, but also fixes each component of the winding section 20 and is used as a cooling path to cool the superconducting coil 1.

[0028] The side insulating material 30 is, for example, an insulating sheet made of the same material as the inter-turn insulating material 26. The side insulating material 30 is provided so as to surround the superconducting coil 1 from above and below in the winding axis direction, and insulates the superconducting coil 1 from other coils adjacent to it in the winding axis direction.

[0029] Next, the manufacturing method of the superconducting coil 1 will be explained with reference to Figure 7.

[0030] The winding section 20 begins to be wound onto the winding drum 10 with the superconducting wire 22, reinforcing material 24, and interturn insulating material 26 stacked in, for example, this order. At this time, for example, the winding section 20 is impregnated with resin by applying the resin that will become the material for the insulating resin layer 28 at the same time as it is being wound.

[0031] When winding the winding section 20, the superconducting wire 22, reinforcing material 24, and inter-turn insulating material 26 are wound while applying the tensile load F1 shown in Figure 7. At this time, a reaction force F2 due to the frictional force balancing the tensile load F1 acts, so that the superconducting wire 22, reinforcing material 24, and inter-turn insulating material 26 are wound without displacement. The compressive force generated by this tensile load F1 pushes the insulating resin layer 28 out from between the superconducting wire 22, reinforcing material 24, and inter-turn insulating material 26, thereby reducing the thickness of the insulating resin layer 28 and improving the space factor, which is the ratio of the cross-sectional area of ​​the superconducting wire 22 to the cross-sectional area perpendicular to the circumferential direction of the superconducting coil 1.

[0032] In this embodiment, an example is shown in which the reinforcing material 24 is wound together with the winding portion 20 over all turns. However, depending on the distribution of hoop stress, the reinforcing material 24 does not need to be wound together with turns that do not exceed the allowable stress of the superconducting wire 22.

[0033] According to this embodiment, since the starting point of the reinforcing material 24 is fixed to the winding drum 10, the frictional force F2 acting on the reinforcing material 24 becomes large, and a strong tensile load F1 can be applied from the starting point of the winding without displacing the reinforcing material 24 together with the superconducting wire 22 and the inter-turn insulating material 26. As a result, when winding the winding section 20, a large compressive force is applied between the superconducting wire 22, the reinforcing material 24, and the inter-turn insulating material 26, pushing out the insulating resin layer 28 and reducing its thickness, thereby improving the packing factor of the superconducting coil 1. In other words, the strength of the magnetic field per unit volume of the superconducting coil 1 can be improved, and a magnetic field can be generated efficiently.

[0034] Furthermore, in the superconducting coil 1 described above, when a current is applied to the superconducting coil 1 in its own magnetic field or an external magnetic field, an electromagnetic force proportional to the magnetic field and the current acts on the superconducting wire 22. When a radial electromagnetic force generated by the winding axis component of the magnetic field acts radially, a tension acts longitudinally on the superconducting wire 22 to balance this electromagnetic force. This tensile stress generated inside the superconducting wire 22 is called hoop stress. The allowable longitudinal stress of the superconducting wire 22 is, for example, several hundred MPa, and if a hoop stress exceeding the allowable stress acts, the superconducting properties of the superconducting wire 22 deteriorate.

[0035] In this embodiment, the superconducting wire 22 and the reinforcing material 24 can be wound together with a strong tensile load F1 from the start of winding. This further suppresses the force that causes the winding portion 20 to expand radially due to the electromagnetic force acting radially on the superconducting coil 1, and allows for a greater distribution of the hoop stress generated inside the superconducting wire 22. Therefore, the allowable stress for hoop stress required to maintain the superconducting properties of the superconducting coil 1 can be improved, resulting in a high-strength superconducting coil 1.

[0036] As a modification of this embodiment, as shown in Figure 8, a fixing member 50 fixed to the winding drum 10 may be provided, and the reinforcing member 24 may be fixed inside the winding drum 10 by being sandwiched between the winding drum 10 and the fixing member 50. The material of the fixing member 50 may be an insulating material such as reinforced plastic or a metal such as copper, silver, aluminum, or stainless steel. The shape of the fixing member 50 is preferably such that when fixed to the winding drum 10, the outer diameter surface becomes a cylinder with a constant curvature. This fixing member 50 may be formed, for example, by cutting it out from the winding drum 10. The winding drum 10 and the fixing member 50 are fixed together, for example, by an adhesive (not shown).

[0037] As shown in Figure 9, the fixing member 50 may be provided with a female thread portion 52, the winding drum 10 with a through hole 54, and the reinforcing member 24 with a through hole 56, and the reinforcing member 24 may be fixed to the winding drum 10 with a fixing member 51 (male thread). Alternatively, the fixing member 51 may be, for example, a nail or screw, and should be fixed by passing through the reinforcing member 24. Furthermore, the position where the reinforcing member 24 is fixed may be on the winding frame 12 of the winding drum 10 or on the coil electrode 14.

[0038] As another modification of this embodiment, as shown in Figures 10 and 11, the reinforcing material 24 may be fixed inside the winding drum 10 by inserting it at the connection point between the winding frame 12 and the coil electrode 14 in the winding drum 10. The winding frame 12, coil electrode 14, and reinforcing material 24 are fixed together, for example, with an adhesive.

[0039] In Figure 10, the reinforcing member 24 is fixed to the winding drum 10 so as to extend in the circumferential direction. On the other hand, in Figure 11, the reinforcing member 24 is fixed to the winding drum 10 so as to extend in the opposite direction to the circumferential direction, and the reinforcing member 24 is wound around the drum by bending it in the circumferential direction from the fixing point.

[0040] The same effects as in this embodiment can be obtained in the modified versions described above.

[0041] The positional relationship between the superconducting wire 22 and the reinforcing material 24 is not limited to the example described above; it is sufficient that the superconducting wire 22 is connected to the coil electrode 14. Furthermore, while it is preferable that the superconducting wire 22 is on the inner circumference side in the positional relationship between the superconducting wire 22 and the reinforcing material 24 in the same turn, it is not limited to this.

[0042] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, modifications, and combinations are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0043] 1...Superconducting coil, 10...Winding drum, 12...Winding frame, 14...Coil electrode, 20...Winding section, 22...Superconducting wire, 24...Reinforcement material, 26...Interturn insulating material, 28...Insulating resin layer, 30...Side insulating material, 31...Stabilizing layer, 32...Substrate, 33...Orientation layer, 34...Intermediate layer, 35...Superconducting layer, 36...Protective layer, 40, 50, 51...Fixing members, 52...Female thread section, 54, 56...Through holes.

Claims

1. The rolled drum and The winding section, in which superconducting wire and reinforcing material are wound around the winding drum, The winding portion comprises an insulating resin layer impregnated with at least a portion thereof, A superconducting coil characterized in that, at least a portion of the reinforcing material has a fixing member, separate from the insulating resin layer, positioned between the reinforcing material and the winding drum on the winding frame constituting the winding drum, and the end of the reinforcing material is fixed to the surface of the winding frame by this fixing member.

2. The superconducting coil according to claim 1, characterized in that the fixing member is an adhesive.

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