JP2009188108A - Superconductive coil and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superconductive coil capable of appropriately holding an allowable current value in the superconductive coil by reducing the tensile stress of a superconductive layer caused by a difference in the thermal coefficient of expansion between the substrate of a superconductive tape wire and a reinforced tape wire, when the superconductive coil is operated under a low-temperature atmosphere. <P>SOLUTION: The superconductive tape wire 11 and the reinforced tape wire 21 are laminated on a first electrode terminal 34 provided at a winding core 33 of a roll frame 31 for connecting its starting end, the roll frame 31 is rotated under a low-temperature atmosphere, and the superconductive tape wire 11 and the reinforced tape wire 21 are rewound from a bobbin 45 and a bobbin 47, respectively, and taken up on an outer-periphery surface of the winding core 33. After completing winding both the superconductive tape wire 11 and reinforced tape wire 21, termination sections of both the tape wires 11, 21 are connected to a second electrode terminal 35. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a superconducting coil used in various devices such as a superconducting power storage device, a magnetic resonance imaging diagnostic device, a nuclear magnetic resonance device, and a magnetic levitation device, and a method for manufacturing the same.

  When a superconducting coil manufactured by winding a superconducting tape wire around a winding core is energized, as shown in FIG. 10A, the current flowing in the coil C becomes an annular shape, and this energizing current causes the coil C to Magnetic flux is generated inside. Due to this magnetic flux, Lorentz force acts on the coil C outward in the radial direction of the coil C as shown in FIG. 10B, and a hoop stress is generated in the coil C. This stress causes the coil C to move in the longitudinal direction. Tensile stress acts. When this tensile stress is applied, assuming that the allowable current value of the superconducting coil is 1 when the stress (strain) is zero as shown in FIG. 11, when the tensile stress is 0.2%, for example, a slight current is applied. When the tensile stress increases more than that, the allowable current value decreases. On the contrary, when compressive stress acts on the coil C, the allowable current value decreases as the compressive stress increases.

In order to solve the above problem, Patent Document 1 proposes the following technique. That is, an oxide superconducting layer is formed on a flexible tape-like base material, and the oxide superconducting layer has a compression pre-strain in the longitudinal direction of the base material. And a superconducting coil in which this superconducting wire is wound around a core has been proposed. When a tensile stress acts on the oxide superconducting layer due to the hoop stress acting on the coil when the superconducting coil is energized, the compressive prestrain of the oxide superconducting layer is offset, and the oxide superconducting layer The distortion is canceled and the allowable current value is prevented from decreasing.
Japanese Patent Laid-Open No. 3-138817

  However, the oxide superconducting wire disclosed in Patent Document 1 is intended for a configuration in which an oxide superconducting layer is laminated on one side of a tape-like substrate and a configuration in which a stabilization layer is formed on the surface of the oxide superconducting layer. Therefore, a technique applicable to oxide superconducting wires having other configurations has been desired. This will be described below.

  In order to improve the performance of the superconducting coil, the current passed through the coil needs to increase. When the allowable value of the energization current is increased, the above-described hoop stress is also increased, and the tensile stress acting on the coil is also increased. In recent years, a superconducting tape wire is composed of a tape-like substrate having excellent tensile strength such as Hastelloy, a superconducting layer formed on one side of the substrate, and a stabilizing layer formed on the surface of the superconducting layer. ing. Further, a plain weave of carbon fiber is integrally formed in a flat shape with an epoxy resin or the like, and this reinforcing sheet material is cut to produce a reinforcing tape wire excellent in tensile strength. Then, after connecting the superconducting tape wire and the starting end of the reinforcing tape wire to the first electrode terminal attached to the core of the winding frame, the both tape wires are wound together in a laminated state on the core. A measure to suppress the tensile stress of the coil generated by the hoop stress is conceivable by connecting the terminal portion to the second electrode terminal attached to the coil substrate.

  However, it has been found that the superconducting coil in which the superconducting tape wire and the reinforcing tape wire are wound together has the following new problems. That is, when the superconducting coil is operated and switched from the normal temperature state to the cryogenic state, the thermal contraction rate of the superconducting tape wire hastelloy when cooling the substrate is large, while the reinforcing tape wire material made of carbon fiber has a heat shrinkage rate. Therefore, the shrinkage of the superconducting layer, which tends to shrink due to the thermal contraction of the substrate of the superconducting tape wire, is suppressed by the reinforcing tape wire, and a tensile stress is applied to the superconducting layer. Therefore, the allowable current value of the superconducting coil decreases, and it is not possible to increase the magnetic field or the energy density by supplying a sufficient current to the superconducting coil, and it is possible to sufficiently reduce the size and cost of the coil. There was a problem that I could not.

  The object of the present invention is due to the difference in the thermal expansion coefficient between the substrate of the superconducting tape wire and the reinforcing tape wire when the superconducting coil is operated in a low temperature atmosphere, eliminating the problems existing in the prior art. An object of the present invention is to provide a superconducting coil that can eliminate the tensile stress of the superconducting layer and appropriately maintain the allowable current value of the superconducting coil, and a method of manufacturing the same.

  In order to solve the above problems, the invention according to claim 1 is directed to a superconducting tape wire formed by forming a superconducting layer on one side of a tape-like substrate, and a thermal expansion coefficient smaller than that of the substrate. A superconducting coil comprising a set reinforcing tape wire and a coil substrate, a winding core, and a winding frame provided with a first electrode terminal and a second electrode terminal, wherein the winding core is formed in a low temperature atmosphere. The superconducting tape wire and the reinforcing tape wire are wound on the outer peripheral surface of the tape in a laminated state, and the start and end portions of both tape wires are connected to the first electrode terminal and the second electrode terminal. Is the gist.

  According to a second aspect of the present invention, in the first aspect, the substrate is selected from the group of materials of Hastelloy, stainless steel, and nickel-tungsten alloy, and the reinforcing tape wire includes a plurality of tape-shaped resins. The gist is that carbon fiber or glass fiber is embedded in the longitudinal direction.

  According to a third aspect of the present invention, there is provided a superconducting tape wire formed by forming a superconducting layer on one side of a tape-shaped substrate, a reinforcing tape wire having a thermal expansion coefficient set smaller than that of the substrate, a coil In a method of manufacturing a superconducting coil using a substrate, a winding core, and a winding frame provided with a first electrode terminal and a second electrode terminal, the superconducting tape wire material with respect to the outer peripheral surface of the winding core of the winding frame in a low temperature atmosphere And a step of winding the reinforcing tape wire in a laminated state, a step of connecting the start and end portions of both tape wires to the first and second electrode terminals, and a step of returning the conductive coil from a low temperature atmosphere to a normal temperature state Including the above.

  The invention according to claim 4 is the invention according to claim 3, wherein after connecting the first end of the superconducting tape wire and the reinforcing tape wire to the first electrode terminal of the winding frame, the two tape wires are connected in a low temperature atmosphere. The gist of the invention is to wind around the outer peripheral surface of the winding core in a laminated state and to connect the end portions of both tape wires to the second electrode terminal in a state where both tape wires are cooled to a low temperature.

The gist of the invention described in claim 5 is that, in claim 4, the temperature under the low temperature atmosphere is set in a range of 64 to 77K.
(Function)
According to the present invention, in a low temperature atmosphere, a superconducting tape wire formed by forming a superconducting layer on one side of a tape-like substrate, and a reinforcing tape wire whose thermal expansion coefficient is set smaller than the thermal expansion coefficient of the substrate. It wound around the core of the winding frame in a laminated state, and connected the first end and the second end of the winding frame to the first and second electrode terminals of both tape wires. For this reason, in the state where the superconducting coil is operated and shifted from the normal temperature state to the low temperature state, both the superconducting tape wire and the reinforcing tape wire are properly cooled and contracted, and the superconducting tape wire follows the shrinkage caused by the cooling of the substrate and is reinforced. The tape wire is also properly cooled and contracted, and the superconducting layer is appropriately cooled and contracted, so that it is possible to prevent the superconducting layer from being loaded with tensile stress due to the reinforcing tape wire.

  The present invention eliminates the tensile stress of the superconducting layer due to the difference in thermal expansion coefficient between the substrate of the superconducting tape wire and the reinforcing tape wire when the superconducting coil is operated in a low temperature atmosphere, and the allowable current value of the superconducting coil. Can be held properly.

An embodiment of a method for manufacturing a superconducting coil embodying the present invention will be described below with reference to FIGS.
The superconducting tape wire 11, the reinforcing tape wire 21, the winding frame 31, and the manufacturing apparatus 41 for manufacturing the superconducting coil will be sequentially described.

First, the structure of the superconducting tape wire 11 will be described with reference to FIGS. 1 and 2.
The tape-shaped substrate 12 constituting the superconducting tape wire 11 is formed of Hastelloy having excellent tensile strength. A first intermediate layer 13 made of Gd ₂ —Zr ₂ —O ₇ is formed on one surface of the substrate 12 by a vapor phase method such as an ion beam assisted vapor deposition method. A second intermediate layer 14 made of cesium oxide (CeO ₂ ) is formed on the surface of the first intermediate layer 13 by a PLD (Pulse Laser Deposition) vapor deposition method or an EB (Electron Beam) vapor deposition method. A superconducting layer 15 is formed on the surface of the second intermediate layer 14 by a CVD (Chemical Vapor Deposition) vapor deposition method, a PLD vapor deposition method or a MOD (Metal-organic deposition) vapor deposition method. As the material of the superconducting layer 15, there is a yttrium-based (Y, Gd, etc.) by _Y 1 _-Ba 2 _-Cu 3 -O _x system or the like. They develop superconducting properties by heat treatment at 400-1000 ° C. Further, a protective layer 16 made of silver which also functions as a stabilizing layer is formed on the surface of the superconducting layer 15 by vapor deposition. In this embodiment, a stabilization layer 17 made of copper is bonded to the surface of the protective layer 16 by solder 18 containing Ag.

  In this embodiment, the width dimension of the superconducting tape wire 11 is, for example, 10 mm. The thickness dimensions of the substrate 12, the first intermediate layer 13, the second intermediate layer 14, the superconducting layer 15, the protective layer 16 and the stabilizing layer 17 are sequentially set to 50 to 100 μm, 0.5 to 1 μm,. 5 to 1 μm, 1 to 2 μm, 3 to 5 μm, and 50 to 200 μm.

  The reinforcing tape wire 21 is formed as shown in FIG. As shown in FIG. 3, the reinforcing tape wire 21 forms a wide belt-like fiber sheet by flat weaving a large number of carbon fibers 22 and cuts the sheet into a tape having a predetermined width as shown in FIG. Manufactured.

  In this embodiment, the reinforcing tape wire 21 has a width dimension of, for example, 10 mm and a thickness dimension of 100 to 200 μm. The coefficient of thermal expansion of the reinforcing tape wire 21 depends on the coefficient of thermal expansion of the carbon fiber 22 instead of the epoxy resin 23 that is later impregnated in the reinforcing tape wire 21, and the coefficient of thermal expansion of the carbon fiber 22 is determined by the superconducting tape wire. 11 is smaller than the thermal expansion coefficient of Hastelloy forming the substrate 12.

  Next, the reel 31 will be described. As shown in FIG. 4, the winding frame 31 connects a cylindrical core 33 made of reinforced plastic such as FRP to one side of a coil substrate 32 made of reinforced plastic such as FRP having insulating properties, and A first electrode terminal 34 is attached to the outer peripheral surface of the winding core 33, and a second electrode terminal 35 is attached to the outer peripheral side of the coil substrate 32.

Next, the superconducting coil manufacturing apparatus 41 will be described with reference to FIGS.
As shown in FIGS. 5 and 6, the case 42 of the manufacturing apparatus 41 is provided with a core rotation mechanism unit 44 including a motor 43 for rotating the winding frame 31 at a predetermined position. Similarly, as shown in FIG. 6, the case 42 is provided with a bobbin support shaft 46 that rotatably supports a bobbin 45, which is wound around the superconducting tape wire 11 in a reel shape, at a predetermined position. Further, the case 42 is equipped with a bobbin support shaft 48 that rotatably supports a bobbin 47 wound with the reinforcing tape wire 21 at a predetermined position.

  As shown in FIG. 7, the case 42 of the manufacturing apparatus 41 is supported by a support frame 49 so that the rotation support shaft 43a of the motor 43 and the bobbin support shafts 46 and 48 face downward. Although not shown, the support frame 49 is provided with a lifting mechanism for the manufacturing apparatus 41. A cooling medium storage tank 51 for storing a cooling medium L such as liquid nitrogen is provided inside the support frame 49. The cooling medium storage tank 51 is provided with a refrigeration mechanism (not shown) for cooling the cooling medium L so as to cool the cooling medium L to a low temperature of, for example, 64 to 200K.

Next, a superconducting coil manufacturing method performed in a low temperature atmosphere using the superconducting tape wire 11, the reinforcing tape wire 21, the winding frame 31, and the manufacturing apparatus 41 will be described.
First, as shown in FIG. 6, the reel 31 is mounted on the rotation support shaft 43 a of the motor 43 of the core rotation mechanism 44 so as to be able to rotate synchronously. Next, the bobbin 45 is rotatably supported on the bobbin support shaft 46, and the bobbin 47 is rotatably mounted on the bobbin support shaft 48. And the front-end | tip part of the superconducting tape wire 11 and the front-end | tip part of the reinforcement tape wire 21 which were unwound from the bobbin 45 and the bobbin 47 are piled up, and it connects with the 1st electrode terminal 34 provided in the said winding core 33 with a volt | bolt.

  Next, the winding frame 31, the bobbins 45, 47 and the like mounted on the manufacturing apparatus 41 enter the inside of the cooling medium L having a temperature of 64 to 74K in the cooling medium storage tank 51 as shown in FIG. Then, the manufacturing apparatus 41 is moved down. In this state, the motor 43 of the core rotation mechanism 44 is driven to rotate the winding frame 31 by the rotation support shaft 43a. Then, the superconducting tape wire 11 and the reinforcing tape wire 21 are rewound, and the superconducting tape wire 11 and the reinforcing tape wire 21 are laminated around the outer peripheral surface of the core 33 a plurality of times in a coil shape.

  After the winding operation of the superconducting tape wire 11 and the reinforcing tape wire 21 around the winding core 33 is finished, the lifting mechanism (not shown) is operated to raise the manufacturing apparatus 41 from the cooling medium storage tank 51. Next, as shown in FIG. 8, the end portions of both tape wires 11 and 21 are connected to the second electrode terminal 35 by bolts. Thereafter, the superconducting tape wire 11 and the reinforcing tape wire 21 are cut, and the superconducting coil obtained in this way is inserted into an epoxy resin solution (not shown) so as to enter the gap between the carbon fibers 22 of the reinforcing tape wire 21. As shown in FIG. 9A, the epoxy resin 23 is impregnated and cured, and the production of the superconducting coil is completed.

  As shown in FIG. 9A, both the tape wires 11 and 21 of the superconducting coil shown in FIG. 8 are such that the substrate 12 of the superconducting tape wire 11 is located inside the coil layer and the stabilizing layer 17 is located outside. The reinforcing tape wire 21 is in a state located outside the stabilization layer 17.

  In manufacturing the superconducting coil, the insulating tape made of polyimide resin is in contact with the lower surface of the substrate 12 of the superconducting tape wire 11 and the insulating tape is wound in a coil shape together with the superconducting tape wire 11. However, this insulating tape is not shown.

According to the method of manufacturing a superconducting coil of the embodiment, the following actions and effects can be obtained.
(1) In the above embodiment, the superconducting tape wire 11 and the reinforcing tape wire 21 are stacked on the core 33 of the winding frame 31 and wound up in a low temperature atmosphere. For this reason, after the manufacture of the superconducting coil shown in FIG. 8 is finished, when the coil is kept in use, the superconducting tape wire 11 and the reinforcing tape wire 21 are cooled to a low critical temperature (for example, 70 to 200 K). In the process, a compressive stress is applied to the superconducting layer 15 by the thermal contraction due to cooling of the superconducting tape wire 11 having a large thermal expansion coefficient. At this time, the reinforcing tape wire 21 having a small thermal expansion coefficient is appropriately shrunk following the cooling and shrinkage operation by cooling the superconducting tape wire 11. The reason why the reinforcing tape wire 21 is properly contracted is that both ends of the tape wire 11 and 21 are fixed by the first and second electrode terminals 34 and 35 when the superconducting coil is returned to the normal temperature state after the manufacture is completed. Therefore, the thermal expansion amount of the superconducting tape wire 11 is larger than the thermal expansion amount of the reinforcing tape wire 21. Therefore, a tensile stress is applied to the reinforcing tape wire 21 due to the thermal expansion of the superconducting tape wire 11. This tensile stress makes it easier for the reinforcing tape wire 21 to cool and shrink. As a result, it is possible to prevent a tensile stress from being generated in the superconducting layer 15 of the superconducting tape wire 11 by the reinforcing tape wire 21 in a cooling atmosphere in which the superconducting coil is used, and the substrate 12 of the superconducting tape wire 11. Compressive stress is generated in the superconducting layer 15 by the thermal contraction. The reason why compressive stress is applied to the superconducting layer 15 in this way is that the thermal expansion coefficient of the superconducting tape wire 11 is larger than the thermal expansion coefficient of the superconducting layer 15. Accordingly, when the superconducting coil is energized, the compressive stress is reduced due to the tensile stress generated by the hoop stress acting on the superconducting layer 15, and the stress is reduced, and the allowable current value of the superconducting layer 15 is set appropriately. Can be held in.

  (2) In the above embodiment, since the reinforcing tape wire 21 is laminated on the stabilization layer 17 side of the superconducting tape wire 11, that is, on the outer peripheral side of the superconducting tape wire 11, as shown in FIG. Can be improved.

In addition, you may change the said embodiment as follows.
As shown in FIG. 9B, the reinforcing tape wire 21 is disposed so that the substrate 12 of the superconducting tape wire 11 is located outside the coil and the stabilizing layer 17 is located inside the coil, and inside the stabilizing layer 17. May be located. In this embodiment, since the substrate 12 of the superconducting tape wire 11 is located outside, the hoop stress when the superconducting layer 15 is energized can be easily supported by the substrate 12, and as a result, the superconducting layer 15 and Peeling of the bonding interface of the protective layer 16 can be suppressed.

-It may be embodied in a double pancake type superconducting coil or a solenoid type superconducting coil.
The first and second intermediate layers 13 and 14 of the superconducting tape wire 11 may be omitted, or the stabilization layer 17 may be omitted.

As the material of the substrate 12 of the superconducting tape wire 11, for example, stainless steel, nickel / tungsten alloy or the like may be used.
The material of the reinforcing tape wire 21 may be, for example, selected from a group of glass fiber, stainless steel, nickel / tungsten alloy and the like instead of the carbon fiber 22.

The partial perspective view of the superconducting tape wire used for the manufacturing method of the superconducting coil of this invention, and a reinforcement tape wire. The expanded longitudinal cross-sectional view of a superconducting tape wire. The expanded longitudinal cross-sectional view of a reinforcement tape wire. The perspective view of the winding frame of a superconducting coil. The bottom view which shows the manufacturing apparatus of a superconducting coil. The bottom view explaining the manufacturing method of a superconducting coil. The front view explaining the manufacturing method of a superconducting coil. The front view of a superconducting coil. (A) and (b) are the partial expanded longitudinal cross-sectional views of a superconducting coil. (A) is a diagram which shows the relationship between the electric current which flows into a superconducting coil, and magnetic flux, (b) is a diagram explaining the hoop stress which acts on a superconducting coil. The graph which shows the relationship between the distortion which acts on the superconducting layer of a superconducting coil, and an allowable electric current value.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11, 21 ... Tape wire, 11 ... Superconducting tape wire, 12 ... Substrate, 15 ... Superconducting layer, 21 ... Reinforcement tape wire, 22 ... Carbon fiber, 31 ... Winding frame, 32 ... Coil substrate, 33 ... Core, 34 ... 1st electrode terminal, 35 ... 2nd electrode terminal.

Claims (5)

A superconducting tape wire formed by forming a superconducting layer on one surface of a tape-like substrate, a reinforcing tape wire whose thermal expansion coefficient is set smaller than the thermal expansion coefficient of the substrate, a coil substrate, a winding core, and a first electrode terminal And a superconducting coil constituted by a winding frame having a second electrode terminal,
Under a low temperature atmosphere, the superconducting tape wire and the reinforcing tape wire are wound around the outer peripheral surface of the core of the winding frame in a laminated state, and the start and end portions of both tape wires are the first electrode terminal and A superconducting coil connected to the second electrode terminal. 2. The substrate according to claim 1, wherein the substrate is selected from the group of materials of hastelloy, stainless steel and nickel / tungsten alloy, and the reinforcing tape wire includes a plurality of carbon fibers or glass fibers in the longitudinal direction with respect to the tape-shaped resin. A superconducting coil characterized by being embedded. A superconducting tape wire formed by forming a superconducting layer on one surface of a tape-like substrate, a reinforcing tape wire whose thermal expansion coefficient is set smaller than the thermal expansion coefficient of the substrate, a coil substrate, a winding core, and a first electrode terminal And a method of manufacturing a superconducting coil using a winding frame having a second electrode terminal,
Under a low temperature atmosphere, the step of winding the superconducting tape wire and the reinforcing tape wire on the outer peripheral surface of the core of the winding frame in a laminated state;
Connecting the start and end portions of both tape wires to the first and second electrode terminals;
And a step of returning the conductive coil from a low-temperature atmosphere to a normal temperature state. In Claim 3, after connecting the starting end part of the superconducting tape wire and the reinforcing tape wire to the first electrode terminal of the winding frame, both tape wires are laminated on the outer peripheral surface of the core in a low temperature atmosphere. A method of manufacturing a superconducting coil, comprising winding and connecting the terminal portions of both tape wires to a second electrode terminal in a state where both tape wires are cooled to a low temperature. 5. The method of manufacturing a superconducting coil according to claim 4, wherein the temperature in the low temperature atmosphere is set in a range of 64 to 77K.

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