JP2971660B2 - Superconducting magnet device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting magnet apparatus, and more particularly to a superconducting magnet apparatus used for levitation propulsion of a magnetic levitation train.

[0002]

2. Description of the Related Art Many superconducting magnet devices for levitation mounted on a magnetic levitation train are configured as shown in FIGS. These figures show an example in which a superconducting coil formed in an annular shape, that is, a racetrack-shaped superconducting coil 1 which is vacuum-impregnated with epoxy resin after winding is provided.

A superconducting coil 1 is housed in a heat insulating container 2. The heat-insulating container 2 has a racetrack-like container 2 similar to the shape of the superconducting coil 1,
An inner container 4 containing therein a superconducting coil 1 and a refrigerant liquid represented by liquid helium, an outer container 5 containing the inner container 4 at room temperature, and a space between the outer container 5 and the inner container 4. And a heat-insulating shield plate 6 provided at the end.

The inner container 4 is usually made of a non-magnetic material such as stainless steel for the purpose of securing mechanical strength, and is fixed in the outer container 5 via a plurality of heat insulating supports (not shown). The superconducting coil 1 is firmly fixed in the inner container 4 with the refrigerant passage secured. The space between the inner container 4 and the outer container 5 is evacuated to form a vacuum heat insulating layer.

[0005] The heat insulating shield plate 6 is located in the vacuum heat insulating layer, and is usually formed of a metal material such as copper or aluminum having good heat conductivity. This heat insulating shield plate 6 is cooled to an intermediate temperature by a cooling system (not shown). In addition,
In FIG. 11, 7 is provided to reinforce the inner container 4,
For example, a reinforcing member made of stainless steel is shown. Such a structure is employed to achieve high strength, light weight, and compactness. However, the superconducting magnet device configured as described above has the following problems. That is, when the superconducting magnet device is mounted on a magnetically levitated train and travels, the amount of evaporation of the refrigerant liquid in the inner container 4 usually increases as compared with a case where the train is stationary.

This is thought to be due to the following mechanism. That is, when the train starts running, the electromagnetic force between the mounted superconducting magnet device and the levitation and propulsion coils arranged on the ground side fluctuates. The fluctuation of the electromagnetic force causes the superconducting coil 1 to vibrate, and this vibration causes a relative displacement between the superconducting coil 1 and either the inner container 4, the heat insulating shield plate 6, or the outer container 5. Here, for example, when a relative displacement occurs between the superconducting coil 1 and the heat-insulating shield plate 6, an eddy current is generated in the heat-insulating shield plate 6 by the relative displacement, and the inner container 4 is constituted by the fluctuating magnetic field generated by the eddy current. An eddy current flows through the wall where the liquid is present, and the heat generated on the inner container wall by the eddy current increases the evaporation amount of the refrigerant liquid. For this reason, the conventional superconducting magnet apparatus has a problem that a refrigerator having a large capacity must be mounted on the train.

Therefore, in order to solve such a problem, the inner container is made of a non-magnetic material such as fiber reinforced plastic,
Although it is conceivable to use a non-conductive material, it is unavoidable to increase the overall size in order to obtain the same mechanical strength as when using a stainless steel rope.

[0008]

As described above, in the conventional superconducting magnet apparatus, especially when mounted on a magnetically levitated train, the amount of refrigerant liquid evaporating is increased, and the refrigerator having a large capacity is required. There was a problem that required.

Accordingly, the present invention provides a superconducting magnet apparatus which can suppress the amount of refrigerant liquid from evaporating even if it is mounted on a magnetically levitated train without complicating the structure and reducing the mechanical strength. It is intended to provide.

[0010]

According to the present invention, there is provided a magnetic levitation type train,
Between the levitation and propulsion coils located on the upper side
Levitating a maglev train by the generated electromagnetic force
For the superconducting magnet device
The shape of the superconducting coil and the shape of the superconducting coil
The superconducting coil formed in a similar race track shape
And an inner container containing the refrigerant liquid and the inner container
An outer container, provided between the outer container and the inner container
The heat insulation shield and the heat insulation shield side of the inner container
Wall facing the coil placed on the ground side
Having a higher conductivity than the members constituting the inner container
Selective superconducting material, at least a part of the superconducting material
And normal conduction dislocation means for transposing to normal conduction
It is characterized by: In addition, the superconducting material is discontinuously discontinued.
It is characterized by being provided in a distributed manner. In addition, the super
It is characterized in that the conductive material is formed in a mesh shape.

[0011]

[0012]

[0013]

[0014]

[0015]

A superconducting coil and a metal container (container) or a metal member disposed outside the container (an outer container containing the container or a heat insulating shield plate disposed between the outer container and the container) ), The magnetic field fluctuates, and an eddy current is generated in a container (container) containing the superconducting coil and the refrigerant liquid. Generally, when an eddy current flows because the container is metallic, the container generates heat due to the resistance of the metal.

In the present invention, the superconducting material having a higher conductivity than the members constituting the container is provided discontinuously distributed on the outer surface of the container, or the superconducting material is meshed on the outer surface of the container. Or provided on the wall on the side close to the coil disposed on the ground side facing the heat-insulating shield side of the inner container, and causing the generated eddy current to flow through these superconducting materials. Accordingly, heat generation of the container storing the refrigerant liquid is suppressed, and the amount of evaporation of the refrigerant liquid (for example, liquid helium) can be suppressed to an extremely small amount.

[0017] Particularly, when a non-continuously distributed on the surface of the container, for example islands (islands) shaped provided with superconducting material, path entire container when whole would provide a superconducting material eddy currents of the container To solve the problem of a large closed loop flowing through
Eddy current heat generation can be greatly suppressed. Further, when the superconducting material is used to form a mesh, the ultra the entire surface of the container
Compared to the case where an electric conductor is provided, there is no possibility of magnetic flux jumping (so-called flux jump) and the effect of the magnetic shield is weak, so an external magnetic field (floating and propulsion coils placed on the ground) It is particularly suitable for use in maglev trains without fear of canceling out magnetic fields.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the superconducting magnet device of the present invention will be described below with reference to the drawings.

As an explanation, an example in which the superconducting magnet device is applied to a magnetically levitated train will be described. However, in the superconducting magnet device of the present invention, the superconducting coil vibrates relative to other metal members and generates a magnetic field. Fluctuates, and an eddy current is generated in a container containing the superconducting coil and the refrigerant liquid, and can be applied to other superconducting applied devices, such as MRI. (Example 1)

FIG. 1 shows a superconducting magnet device according to a first embodiment of the present invention, in which a superconducting magnet device to which the present invention is applied and which is mounted on a magnetic levitation train and used for levitation is locally used. Is shown in In this figure, the same parts as those in FIG. 12 are indicated by the same reference numerals. Therefore, a detailed description of the overlapping part will be omitted.

In this example, when actually mounted on a train, it is assumed that the right side in the figure faces a ground coil (not shown). The inner container 4 is formed of a non-magnetic metal material such as stainless steel , and the heat insulating shield plate 6 is formed of a metal material.

In this type of superconducting magnet device, since the distance between the superconducting coil 1 and the ground coil is limited,
Usually, the inner container 4 containing the superconducting coil 1 is disposed in the outer container 5 on the right side in the drawing. Therefore, of the two walls that constitute the inner container 4 and that oppose the heat-insulating shield plate 6 in the axial direction of the superconducting coil 1, the wall 11 that is located on the right side in FIG. And part 1 of heat insulation shield plate 6
2 is shorter than the other portions.

In the portion where the distance L is short, when the relative displacement occurs between the superconducting coil 1 and the heat insulating shield plate 6 as described above, a large eddy current easily flows through the portion 12 of the heat insulating shield plate 6. When a fluctuating magnetic field is generated by the eddy current, an eddy current flows through the wall 11 under the influence of the fluctuating magnetic field,
The wall 11 generates heat due to the eddy current. This heat generation increases the evaporation of the refrigerant liquid contained in the inner container 4 as described above.

In order to solve such a problem, in this embodiment, the wall constituting the inner container 4 is provided on the outer surface of the wall 11 located on the side of the ground coil, as shown in FIGS. As shown in FIG. 1, closed current paths (eddy current paths) 15 and 16 for forming an eddy current flow path are provided so as to border the outer edge 13 and the inner edge 14 thereof.

The closed current paths 15 and 16 are made of a material having higher conductivity than the metal material forming the wall 11, in this embodiment, a superconducting wire. Specifically, it has a matrix of copper or cupronickel, and is formed of a composite superconducting wire having a DC monolith conductor configuration, a DC strand conductor configuration, an AC monolith conductor configuration with reduced AC loss, an AC strand conductor configuration, and the like. And as a wire, NbT
i, an alloy system such as NbZr, Nb ₃ Sn, intermetallic compound-based, such as V ₃ Ga is used.

The ends of these superconducting wires are soldered or directly connected to each other to form one turn, and are directly fixed to the outer edge 13 and the inner edge 14 of the wall 11 by soldering. ing. These superconducting wires are cooled by the coolant liquid contained in the inner container 4 via the wall 11.

The closed current paths 15, 16 may be formed of an oxide superconductor having a high critical temperature. Also, the wall 11
May be electrically insulated. Further, as the fixing means, a winding frame may be formed on the outer edge portion 13 and the inner edge portion 14 of the wall 11, and may be wound and fixed to the winding frame, or may be wound in advance so as to constitute a closed circuit. The object may be fixed to the outer edge portion 13 and the inner edge portion 14 of the wall 11 with an adhesive such as epoxy resin, or an object formed to form a closed circuit may be fixed using a fixture. You may.

In this embodiment, the closed current paths 15, 16 are formed by superconducting wires. By providing the closed current paths 15 and 16 formed of superconducting wires adjacent to the superconducting coil 1 as described above, when the superconducting coil 1 is deenergized, the closed current paths 15 and 1 are closed.
When a current is induced in the superconducting wire 6 and the current becomes excessive, the superconducting wire may undergo normal conduction dislocation and burn out. Further, due to the existence of the closed current paths 15 and 16 formed by the superconducting wires, the magnetic field generated in the superconducting coil 1 is shielded, and there is a possibility that a desired magnetic field cannot be applied to the outside.

Therefore, in this embodiment, as shown in FIG. 3, electric heaters 17 and 18 are partially provided in closed current paths 15 and 16.
When the superconducting coil 1 is deenergized, current is supplied to the electric heaters 17 and 18 to displace a part of the closed current paths 15 and 16 to normal conduction.
The resistance value of No. 6 is increased to suppress the induced current. In order to have a similar role, the closed current paths 15, 16
May be provided with a thermal permanent current switch. In this case, a protection resistor or a diode is attached to both ends of the switch, and is used for protection when the switch is in normal conduction.

With such a configuration, the superconducting coil 1
The relative displacement between the shield plate 6 and the heat insulating shield plate 6
When an eddy current is generated in the portion 12 described above, a fluctuating magnetic field is generated by the eddy current. This fluctuating magnetic field is applied to the wall 1 of the inner container 4.
Try to act on 1. However, the wall 11 is a closed current path 1
The presence of 5 and 16 provides magnetic shielding from fluctuating magnetic fields. Therefore, the eddy current generated in the wall 11 by the fluctuating magnetic field is suppressed to a small value. As a result, the heat generation of the wall 11 due to the eddy current generated in the wall 11 is suppressed, and the evaporation of the refrigerant liquid is suppressed.

That is, when a fluctuating magnetic field is applied to the wall 11 vertically, the fluctuating magnetic field is applied to the outer edge 13 and the inner edge 14 of the wall 11.
From this, the light diffuses into the wall 11 with the magnetic diffusion constant D = 1 / σμ ₀ . Here, σ is the conductivity of the material forming the wall 11, and μ ₀ is the magnetic permeability. As the conductivity of the material constituting the wall 11 decreases, the magnetic diffusion constant D increases, and the material diffuses in a short time. If the frequency of the fluctuating magnetic field is high, the magnetic diffusion cannot catch up with the fluctuation of the magnetic field, and the magnetic field starts to reach the skin thickness ρ,

[0032]

Ρ = {2 / μ ₀ σω} ^0.5 … (1) only invades. Here, ω is the angular velocity of the fluctuating magnetic field.

Therefore, as in this embodiment, the inner container 4
If the closed current paths 15 and 16 formed of superconducting wires having almost infinite conductivity are provided so as to frame the outer edge 13 and the inner edge 14 of the wall 11 in In addition, diffusion to the outside from the inner edge portion 14 can be prevented.

That is, the closed current paths 15 and 16 can exhibit a magnetic shielding function, thereby suppressing the eddy current from flowing through the wall 11 and suppressing the heat generation of the wall 11 caused by the eddy current. The evaporation of the refrigerant liquid in the vessel 4 can be suppressed.

According to the calculations by the inventors, the following results were obtained. That is, inner diameter 44cm, outer diameter 58cm, thickness 3mm
A hollow disk made of stainless steel is used as a target, and has a single amplitude of 10 Gauss and a vibration frequency of 300 perpendicular to the surface of the hollow disk.
When a fluctuating magnetic field of Hertz was applied, the eddy current value at a position set every 1 cm from the inner peripheral edge of the hollow disk was substantially uniform from 13 A to 17 A. The state of the change of the eddy current measured in this way is shown as a solid line A in FIG.
FIG. 4 shows a change in the eddy current immediately after the application of the magnetic field at a certain position. As described above, the eddy current at each position of the disk shows almost the same value because of the skin thickness ρ calculated from the permeability, the conductivity of the stainless steel , and the oscillation frequency of the fluctuating magnetic field.
Is close to the radial width of the hollow disk of 7 cm, and the magnetic field is 7 cm in width.
By invading the entire range of

On the other hand, when a closed current path formed by a superconducting wire was attached to the outer edge and inner edge of the same hollow disk, and a fluctuating magnetic field was applied thereto under the same conditions as described above, as shown in FIG. Although a current of 135 A flows through the outer closed current path and a current of 94 A flows through the inner closed current path, the eddy current flowing through each portion in the radial direction of the hollow disk becomes 3 A as shown by a solid line B in FIG.
From 5A to 1/5 compared to the case where the closed current path is not attached (solid line A in FIG. 4).

Therefore, if the closed current paths 15 and 16 formed by superconducting wires are provided at the outer edge 13 and the inner edge 14 of the wall 11 as in the embodiment, the
1 can be suppressed, and as a result, the inner container 4
The evaporation of the refrigerant liquid in the inside can be suppressed. (Embodiment 2) FIG. 6 schematically shows only a main part of a superconducting magnet device according to a second different embodiment of the present invention.

In this embodiment, three closed current paths 19, 20, and 21 are added to the embodiment shown in FIG. These three closed current paths 19, 20, 21
Like the closed current paths 15 and 16, they are formed by one-turn superconducting wires.

The closed current path 19 is a wall 11 constituting the inner container 4, a portion 22 forming one curved portion, and one reinforcing portion provided to connect both ends of the portion 22. It is provided on the inner edge of the peripheral circuit formed by the member 7. Further, the closed current path 20 is connected to the wall 11 constituting the inner container 4.
The inner edge of the peripheral circuit formed by the two portions 23 and 24 forming the linear portion and the two reinforcing members 7 and 7 provided so as to connect both ends of the two portions 23 and 24. It is provided in.

Further, the closed current path 21 is a portion 2 of the wall 11 forming the inner container 4 and forming the other curved portion.
5 and the other reinforcing member 7 provided so as to connect both ends of the portion 25 is provided at an inner edge of a peripheral circuit formed by the reinforcing member 7. A portion of each of the closed current paths 19, 20, and 21 is energized when the superconducting coil 1 is demagnetized, and a part of each of the closed current paths 19, 20, and 21 is displaced to normal conduction. Electric heaters 26, 27, 28 for suppressing the induced current by increasing the resistance values of the closed current paths 19, 20, 21
Is wound or attached.

Even with such a configuration, the same effect as in the above embodiment can be obtained. In this embodiment, when the reinforcing members 7, 7 are formed of a non-conductive material, the closed current path 1
9, 20, 21 can be omitted. (Modification 1)

The present invention is not limited to the embodiment described above. That is, in each of the above-described embodiments, each closed current path is configured by one turn of the superconducting wire, but may be configured by a plurality of turns. Further, in each of the above-described embodiments, the closed current path is provided at the outer edge and the inner edge of the wall forming the inner container 4, but one or more closed current paths are further provided at an intermediate position where these are provided. A road may be provided. Further, in the above-described embodiment, the closed current path is provided on the outer surface of one wall facing the heat insulating shield plate in the axial direction of the superconducting coil with the wall constituting the inner container,
A closed current path may be provided on the outer surface of the other wall or on the outer surfaces of the remaining two walls.

Further, in each of the above-described embodiments, the closed current path is constituted by a superconducting wire, but a good conductive material having a higher conductivity than the material forming the inner container, such as copper, aluminum, aluminum alloy, etc. May be formed. In this case, the fluctuating magnetic field penetrates into a region having a width represented by the expression (1). Therefore, a closed current path may be formed with a good conductive material having a width of about twice this width.

For example, taking the case where the frequency of the fluctuating magnetic field is 300 Hz and the closed current path is made of oxygen-free copper,
Since the skin thickness ρ is 0.3 mm according to the equation (1),
A wire having a width of 0.6 mm may be used. Also in this case, the installation place can be variously selected as in the case of forming with a superconducting wire.

In the above embodiment, the closed current paths 15, 1
Although 6 is provided on the outer wall of the inner container 4, it may be provided on the inner wall, or may be provided on both the outer wall and the inner wall.

In the above embodiment, the closed current paths 15, 1
6 is provided on the outer wall of the inner container 4 on the side closer to the ground coil, but is not limited to this, and the upper wall, the lower wall, and the wall of the inner container 4 far from the ground coil are not limited thereto. It may be provided on any part, or may be provided on all of those external walls.

Further, a conductor is interposed between the closed current paths 15 and 16 at appropriate intervals along the direction in which the closed current paths 15 and 16 extend, so that various portions of the outer wall of the inner container 4 are provided. May be effectively reduced. Further, another closed current path composed of a superconducting wire or the like may be further added between the two closed current paths 15 and 16 to form, for example, three or more closed current paths. In addition, various modifications can be made without departing from the spirit of the present invention. (Example 3)

Next, FIG. 7 schematically shows only a main part of a superconducting magnet device according to a third embodiment of the present invention. The same parts as those in the first and second embodiments are denoted by the same reference numerals, and the description is omitted. The configuration of the third embodiment is characterized in that a closed current path serving as an eddy current path for flowing an eddy current is configured as a mesh circuit.

That is, on the outer surface of the wall 11 located on the ground coil side of the inner container 4, a mesh circuit 30 formed by using a composite superconducting wire using copper as a matrix is provided. In the mesh circuit 30, the superconducting wires are not insulated, and the superconducting wires are arranged in different directions, and the layers and the turns are connected by solder such as lead-tin, indium, etc., and the connection resistance between the wires is reduced. It is formed in a metsche shape. In order to obtain an effective magnetic shielding effect, the mesh interval of the superconducting wires is desirably about 10 mm or less.

The mesh circuit 30 is fixed to almost the entire outer surface of the wall 11 located on the ground coil side of the inner container 4 with lead-tin, indium solder or the like. The use of the superconducting mesh circuit 30 provides the following remarkable functions and effects.

By forming the superconducting wire in a mesh shape, an extremely stable effect can be obtained as compared with a case where a superconducting material sheet (plate) is used. The reason is,
In the superconducting sheet, a magnetic flux jump frequently occurs in the superconducting sheet during excitation of the superconducting coil 1, thereby causing the liquid helium to boil or changing the current of the superconducting coil 1 in a pulsed manner. There is a disadvantage that the superconducting coil 1 is easily quenched. Also, even when no magnetic flux jump occurs, the magnetic field generated by the superconducting coil 1
There is a drawback that the magnetic field is confined by the superconducting sheet and the external magnetic field is canceled.

However, the superconducting mesh is essentially stable, and there is no possibility that a magnetic flux jump occurs. Further, when the superconducting coil 1 is excited, the magnetic field of the superconducting coil 1 is once shielded by the superconducting mesh. Unlike the case of a sheet, it can be transmitted to the outside in a short time of several tens of seconds,
The external magnetic field is not canceled.

The superconducting wires forming the superconducting mesh circuit 30 include a DC monolith conductor, a DC strand conductor, and a matrix of copper, copper alloy, aluminum, or the like.
An AC monolith conductor, an AC strand conductor, or the like in which the occurrence of AC loss is suppressed can be used.

The wire may be not only a composite multifilament wire but also a monofilament conductor or a superconductor having no matrix. Further, as the superconducting material, an alloy-based conductor such as NbTi or an intermetallic compound-based conductor such as Nb ₃ Sn or V ₃ Ga may be used. In the latter case, first, a superconducting mesh circuit is formed, and then the compound is formed. Heat treatment for generation may be added, or production may be performed in the reverse process.

[0055] Further, the formation of the superconducting mesh circuit 30, the superconducting wire without insulation may be used as the knitted cloth, in this case, between the stitches of the superconducting wire may be connected by soldering or the like , May simply be woven. further,
The superconducting mesh circuit 30 may use one kind of the above-mentioned wires, or may use several kinds of wires in combination.

The mesh circuit 30 may be attached to the inner container 4 by a method such as screwing, welding, or the like, instead of being fixed by soldering. At that time, the mesh circuit 30 may be insulated from the inner container 4, It is not necessary to insulate. The superconducting mesh circuit 30 may be attached only to the outer surface of the wall 11 located on the ground coil side of the inner container 4, or may be attached to another surface or the reinforcing member 7. (Example 4)

Next, FIG. 8 partially shows a superconducting magnet device according to a fourth embodiment of the present invention. The first
The same parts as those of the second embodiment are denoted by the same reference numerals, and description thereof is omitted. The configuration that is characteristic of the fourth embodiment is as follows.
This is a method of arranging and forming a superconducting mesh circuit, which means that the superconducting mesh circuit is arranged in an island shape. The superconducting mesh circuit 30 may be provided also on the outer surface of the wall 11 located on the ground coil side of the inner container 4 or on another surface as shown in FIG.

While the superconducting coil 1 (main coil) is being excited, a large loop eddy current 35 is generated as shown in FIG. 9 due to the magnetic coupling between the superconducting coil 1 and the mesh circuit 30. Further, when the reinforcing member 7 is provided, an eddy current circulating around the reinforcing member 7 is also generated. Heat generation due to this kind of eddy current during excitation of the superconducting coil 1 is inversely proportional to the orbital resistance of the superconducting mesh circuit 30. Since the superconducting mesh has sufficiently low resistance, the superconducting coil 1
Large eddy current heat generation may occur during the excitation of.

In the fourth embodiment, the superconducting mesh circuit 30 is divided into islands , distributed discontinuously, and attached to the outer surface of the inner container 4. By distributing the islands in a discontinuous manner in an island shape, the loop of the eddy current can be reduced, and thereby the eddy current heat generation during excitation of the superconducting coil 1 can be largely suppressed.

In order to obtain an effective magnetic shielding effect, the superconducting mesh circuit 30 distributed in an island shape is used.
The distance between them is set to, for example, 1 mm or less. Thereby, the superconducting mesh circuit 30 is distributed in an island shape, and the eddy current heat generation during excitation of the superconducting coil 1 is largely suppressed, and the magnetic shield effect can be maintained well. (Example 5)

Next, FIG. 10 schematically shows only a main part of a superconducting magnet device according to a fifth embodiment of the present invention. The same parts as those in the first and second embodiments are denoted by the same reference numerals, and the description is omitted.

The fifth embodiment is characterized in that a conductor such as copper, copper alloy or the like is provided on the outer surface of the inner container 4 by plating or the like. The superconducting mesh circuit 30 is attached to the surface of the inner container 4 having the plating layer 33 on which the conductor is plated by soldering or the like over the entire circumference or in an island shape.

With the configuration in which the conductor plating layer 33 is provided on the outer surface of the inner container 4 as described above, the superconducting mesh circuit 30 can be easily adhered to the inner container 4 by soldering, and the superconducting coil 1 can be excited during the excitation or in the permanent current mode. Even if a part of the superconducting mesh circuit 30 becomes normal conducting, the current flowing in the superconducting mesh circuit 30 is shunted to the plating layer 33, and after a while, the superconducting mesh circuit 30 is changed from the normal conducting state to the superconducting state. Can recover. The plating layer 33 may be made of aluminum, an aluminum alloy, or the like in addition to copper or a copper alloy.

The position where the mesh circuit is attached is as follows.
Similar to the first and second embodiments (as described in the modified example), it can be attached to various places such as the inner wall of the inner container.

In the third to fifth embodiments, a mesh made of a superconducting wire is used as the mesh circuit. However, the present invention is not limited to the superconducting wire, and the inner container 4 is not limited to the superconducting wire.
Other conductive materials (metals exhibiting good electrical conductivity at low temperature) having higher conductivity than the above, copper, aluminum and the like may be used.

In the first to fifth embodiments, the closed current path and the mesh circuit may or may not be grounded to the outer container 5. Further, an insulating material may be interposed between the closed current path and the mesh circuit.

In the first to fifth embodiments, if the metallic heat insulating shield plate 6 is made of, for example, CFRP (carbon fiber reinforced plastic) or the like, the superconducting coil 1 and the CFRP heat insulating shield plate 6 can be used. When the superconducting magnet device is mounted on, for example, a magnetic levitation train, no eddy current is generated in the heat insulating shield plate 6 even when the superconducting magnet device is relatively displaced. In addition, heat generation of the inner container 4 is extremely greatly suppressed. As a result, the evaporation amount of the refrigerant (liquid helium or the like) can be significantly reduced, and the effect is extremely large in industry.

[0068]

As described above, according to the present invention,
When the superconducting coil vibrates relative to other metal members,
The configuration is such that the container is prevented from generating heat due to eddy current generated in the container storing the superconducting coil and the refrigerant liquid. Therefore, evaporation of the refrigerant liquid stored in the container can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a superconducting magnet according to a first embodiment of the present invention, which is locally extracted.

FIG. 2 is a perspective view showing a main part of the superconducting magnet shown in FIG.

FIG. 3 is a front view of the inner container showing an arrangement relationship of heat generation suppressing means (closed current path) provided in the superconducting magnet shown in FIG.

FIG. 4 is a diagram showing the level of an eddy current generated by a fluctuating magnetic field when the heat generation suppressing unit of the present invention is not provided and when it is provided.

FIG. 5 is a diagram showing a level of a current induced in the closed current path when a closed current path as heat generation suppressing means of the present invention is provided.

FIG. 6 is a front view of an inner container showing an arrangement relation of heat generation suppressing means (closed current path) in a superconducting magnet according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a superconducting magnet according to a third embodiment of the present invention, which is locally extracted.

FIG. 8 is a front view of an inner container showing an arrangement relationship of heat generation suppressing means (closed current path) provided in a superconducting magnet according to a fourth embodiment of the present invention.

FIG. 9 is a schematic diagram showing an eddy current generated in the inner container.

FIG. 10 is a perspective view showing a main part of a superconducting magnet according to a fifth embodiment of the present invention, which is locally extracted and shown.

FIG. 11 is a partially cutaway view of a superconducting magnet device mounted on a magnetic levitation train and used for levitation.

FIG. 12 is a sectional view of the superconducting magnet taken along line AA in FIG. 11;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 superconducting coil 2 heat insulating container 3 container 4 inner container 5 outer container 6 heat insulating shield plate 7 reinforcing member 11 wall 12 part 13 outer edge 14 inner edge 15, 16, 19, 20, 21 closed current path (heat generation suppressing means (vortex Current path)) 17, 18, 26, 27, 28 Electric heater (normal conduction dislocation means) 30 Superconducting mesh circuit (heating suppression means (eddy current path)) 33 Plating layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-52203 (JP, A) JP-A-1-126150 (JP, A) JP-A-47-23089 (JP, A) 114949 (JP, U) (58) Fields studied (Int. Cl. ⁶ , DB name) B60L 13/04 B60L 13/02 H01F 6/00 H01F 6/04 H01F 6/06 H02K 41/02

Claims (3)

(57) [Claims] 1. Mounted on a maglev train and located on the ground side
Generated between the levitation and propulsion coils
Superpower for levitating a magnetically levitated train by magnetic force
The superconducting magnet formed in a race track shape
The conducting coil and a laser similar to the shape of the superconducting coil
Formed in the shape of a track, the superconducting coil and the refrigerant liquid
And an outer container containing the inner container,
Insulating seal provided between the outer container and the inner container
And the heat shield side of the inner container.
Provided on the wall on the side close to the coil arranged on the ground side
Superconducting material having a higher conductivity than the members constituting the inner container
Selectively superconducting at least a portion of the superconducting material
A superconducting magnet device comprising: a normal conducting transposition means for transposing . 2. The superconducting material is provided in a discontinuous distribution.
Superconducting magnet apparatus according to claim 1, wherein the a. 3. The superconducting material is formed in a mesh shape.
The superconducting magnet device according to claim 1, wherein: