JP2583363B2 - Superconducting switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a bifilar type superconducting flow path for controlling a current flowing through a superconducting material,
The present invention relates to a superconducting switch using a transition between a superconducting state and a normal state of a superconducting wire as an opening and closing operation of a switch mechanism. Such a switch is preferably
Used by connecting to a superconducting coil such as a magnetic levitation train or a magnetic resonance imaging device.

[0002]

2. Description of the Related Art In a superconducting coil of a magnetic levitation train or a magnetic resonance imaging apparatus, the above-described superconducting switch is conventionally connected and used in order to keep a constant current flowing for a long time. The main types of superconducting switches are classified into two types. One type uses mechanical movement as the opening and closing operation of a switch using contact and disconnection of a contact. Another type is a temperature-dependent switch that utilizes a change in the conduction state of a superconducting wire due to a change in temperature. That is, the temperature-dependent type superconducting switch functions as a switch opening / closing operation by making a transition between a normal state (resistance state) and a superconducting state (no resistance state) of the superconducting wire. In the present circumstances,
Due to their small size, light weight, easy operability, and relatively low conduction resistance when the switch is closed, temperature-dependent superconducting switches dominate. To manufacture a superconducting switch that is lightweight, compact and has a high current density, the superconducting wire is wound so that the electromagnetic induction of the superconducting wire itself is minimized. In such a configuration, the magnetic field generated by the superconducting wire itself is reduced, and the critical current that can flow through the superconducting wire is increased. More specifically, as shown in FIGS. 1 and 2, a prior art temperature-dependent type superconducting switch is wound around a cylindrical winding shaft 2 in a bifilar manner. Such a superconducting switch is disclosed in Japanese Patent Publication No. 56-26993.
In this case, two superconducting flow paths 1a and 1b each having an end 1c, and the ends 1c are integrated with each other.
Constitute one superconducting wire 1. The superconducting flow paths 1a and 1b are wound around the winding shaft 2 at equal intervals so that the two superconducting flow paths 1a and 1b are in contact with each other over the entire winding. Superconducting flow paths 1a, 1b
Are connected to the positive terminal and the negative terminal of the external device, respectively, so that the current is
Flows to The superconducting switch is turned off by activating a heater wire 3 for heating the superconducting flow paths 1a and 1b, and turned on by cooling the superconducting flow paths 1a and 1b with liquid helium or another refrigerant. Done. Which refrigerant to use will depend on the critical temperature of the superconducting material used in the superconducting channels 1a, 1b. FIG. 1 shows, by broken lines, an impregnating agent 4 for impregnating liquid helium and a casing 5 for protecting the internal structure. (In FIG. 2, the illustration of the heater wire 3, the impregnating agent 4, and the casing 5 is omitted.) Generally, as the superconducting material for the superconducting wire 1 in order to increase the current density when the superconducting switch is on, Nb-Ti alloy is used. In this case, Nb-T
The i-alloy is formed as a number of ultrafine superconducting wires having a diameter of several microns, and the superconducting wires are arranged along the length of the superconducting wire 1. On the other hand, when the switch is off ,
In order to secure a high resistance, a material having a relatively high electric resistance, for example, a Cu—Ni alloy is used as a base material of the superconducting wire 1. However, such a material having a relatively high resistance does not contribute to stabilization of the superconducting characteristics of the superconducting wire as compared with a conductive material such as copper or aluminum. Therefore, the above-described superconducting wire has an undesirable instability that the state is likely to change from the superconducting state to the normal conducting state (resistance state) when energized. That is, when a material having a relatively high resistance is used as the base material of the superconducting wire 1, it is impossible for extra current to escape from the internal superconducting core wire to the base material. Thus, any unexpected thermal disturbance will cause some of the superconducting core wire to transition to a normal conducting state, and this state transition will cause additional thermal disturbance. This heat causes the effect to spread over the entire superconducting wire 1, and switches the superconducting switch to the OFF state at an unexpected time.
If such a superconducting wire has a large number of superconducting core wires and the critical current is much larger than the normal operating current, the occurrence of the above undesirable phenomenon can be reduced. However, an increase in the number of superconducting core wires would inevitably increase the price, mass and size of the superconducting switch. Therefore, it is necessary to manufacture a lightweight and compact superconducting switch at a low cost, and to prevent thermal disturbance in order to prevent a transition from a non-resistance state to a resistance state when the superconducting switch is not expected. It is believed that such thermal disturbance is mainly caused by a small amount of heat generated by a minute movement of a superconducting wire of several microns due to electromagnetic induction. Conventionally, this type of wire movement has been attempted to be suppressed by setting a superconducting wire in a resin such as an epoxy resin.

[0003]

At present, these superconducting switches are often used under a strong magnetic field, especially when connected to a superconducting coil of a magnetic levitation train or a magnetic resonance imaging apparatus. For example, the superconducting switch receives a magnetic force as indicated by an arrow A in FIG. 2 along its axial direction. In this case, when a current flows in the superconducting switch, the superconducting flow path 1a, which is a forward path of the current, is pressed radially inward with respect to the winding shaft 2 according to Fleming's left-hand rule. At the same time, the superconducting flow path 1b serving as the return path of the current
Is pressed radially outward so as to move away from the winding shaft 2, opposite to the superconducting flow path 1 a. In other words, in the conventional superconducting switch in which the superconducting flow paths 1a and 1b are simply wound in a bifilar form, the wire movement easily occurs due to the electromagnetic force in the opposite direction.
As described above, when the superconducting wire is impregnated with the resin material and the electromagnetic force in the opposite direction is small, the superconducting wire is immovably held by the adhesive force of the resin material that overcomes the electromagnetic force, and the wire movement is suppressed. However, there is a limit in the adhesive force of the resin agent, and if the electromagnetic force is large, the wire movement cannot be prevented. In particular, after the superconducting wire is impregnated with the resin agent at room temperature, the switch is set at -269 ° C.
(4.2K, boiling point of liquid helium)
Since the superconducting wire and the resin material have different thermal contraction rates, the superconducting flow paths 1a and 1b tend to separate from each other. Once the wire movement begins, heat generated by eddy currents in the base of the superconducting wire, and heat generated by friction between adjacent superconducting flow paths, and heat generated by the release of stress when the superconducting wire and the resin material peel off, and In addition, heat is generated due to friction between the superconducting wire and the resin material. As a result, even if the superconducting wire is impregnated with the resin material, the current becomes unstable due to one or several of the above-mentioned mechanisms. In this case, the superconducting switch may transition to a normal conduction state (resistance state) when the conduction is less than half the critical current. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a superconducting switch capable of suppressing a wire movement.

[0004]

In order to solve the above problems SUMMARY OF THE INVENTION The superconducting switch according to claim 1, wherein the present invention has at least a pair of superconducting current paths wound on the winding shaft, the pair of superconducting current The path constitutes an open loop-shaped superconducting wire, and in a superconducting switch in which current flows in each superconducting flow path in the opposite direction and reciprocates, the pair of superconducting flow paths are twisted together over the entire winding shaft. It is characterized by the following.

Further, the superconducting switch according to claim 2 is the superconducting switch according to claim 1, wherein the superconducting wire is
Each superconducting flow path has a rotationally symmetric cross-sectional shape, and each of the superconducting flow paths has substantially the same cross-sectional area as an area obtained by dividing the rotationally symmetric cross-sectional shape by the number of superconducting flow paths forming a superconducting wire. It is a feature.

A superconducting switch according to a third aspect is the superconducting switch according to the second aspect, wherein the superconducting wire is
It has a circular cross-sectional shape, and each of the superconducting flow paths has an area obtained by dividing the circular cross-sectional shape by the number of superconducting flow paths constituting a superconducting wire, and has substantially the same cross-sectional area. Is what you do.

According to a fourth aspect of the present invention, in the superconducting switch according to the third aspect, the cross section of each superconducting flow path is semicircular, and the semicircular plane portions of each superconducting flow path are opposed to each other. It is characterized by having.

A superconducting switch according to a fifth aspect is the superconducting switch according to the second aspect, wherein the superconducting wire is
It has a rectangular cross-sectional shape, and each of the superconducting flow paths has substantially the same cross-sectional area as an area obtained by dividing the rectangular cross-sectional shape by the number of superconducting flow paths forming a superconducting wire. Is what you do.

A superconducting switch according to claim 6 is the superconducting switch according to claim 5, wherein the superconducting wire is
It has a square cross-sectional shape, and each of the superconducting flow paths has an area obtained by dividing the square cross-sectional shape by the number of superconducting flow paths constituting the superconducting wire, and has substantially the same cross-sectional area. Is what you do.

A superconducting switch according to a seventh aspect is the superconducting switch according to any one of the second to sixth aspects, wherein the superconducting wire is formed by compression from the side. Things.

The superconducting switch according to claim 8 is the superconducting switch according to any one of claims 1 to 7, wherein the superconducting wire is a tape or string for suppressing the movement of each superconducting flow path. , A thread, a net, or a fabric.

According to a ninth aspect of the present invention, in the superconducting switch according to any one of the first to eighth aspects, the winding shaft is formed of a material having a smaller heat shrinkage than a superconducting wire. It is characterized by the following.

A tenth aspect of the present invention is the superconducting switch according to the ninth aspect, wherein the winding shaft is formed of quartz glass fiber reinforced plastic.

[0014]

According to the superconducting switch of claim 1 wherein the the present invention, a superconducting switch is, even when placed in a magnetic field by an external magnetic source, a pair of the superconducting current path is twisted together, the pair of superconducting Each superconducting current path
Because the direction of current flowing through the current path in the opposite direction, respectively
The opposite electromagnetic forces generated in the superconducting flow paths cancel each other out. That is, in each twist, one of the super conductive <br/> electrically conducting path suppresses the movement of the other superconducting current path. Therefore, wire movement due to electromagnetic force can be suppressed.

Further , according to the superconducting switch of the second to seventh aspects, the space factor of the superconducting core wire in the superconducting wire can be increased. In other words, these configurations contribute to the manufacture of a compact superconducting switch.

According to the superconducting switch according to claim 8,
The mechanical restraining means, which is any of a tape, a cord, a thread, a net, and a fabric, further suppresses the wire movement of the superconducting wire.

According to the superconducting switch of claim 9 and 10, wherein switch structure, when it is cooled so that the superconducting state, the winding shaft does not shrink enough superconducting wire, wound in a superconducting wire in the winding shaft Increases the tensile force of As a result, the stability of the superconducting wire on the winding shaft is improved. In other words, it is possible to prevent an undesired slip between the superconducting wire and the winding shaft.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, the switch-on operation is performed by cooling the switch with liquid helium, but the present invention is not limited to the use of liquid helium, and for example, liquid nitrogen may be used. It is possible.

The "first embodiment" 3-5 shows a superconducting switch according to a first embodiment of the present invention. In the drawings, reference numeral 2 indicates a cylindrical winding shaft made of an insulating material. As shown in FIG. 3, superconducting wire 1 is wound around cylindrical winding shaft 2. Between the cylindrical winding shaft 2 and the superconducting wire 1,
As shown in FIG. 3, the heater wire 3 is interposed as in the conventional case. The heater wire 3 is an electric heating wire, and is arranged vertically and horizontally around a cylindrical winding shaft.

Since this superconducting switch is used in a cryogenic state, the heater wire 3 is made of a resistance material which does not show brittleness even in a cryogenic state. Further, it is preferable that the resistance of the heater wire 3 be constant regardless of a change in temperature. In view of these requirements, the heater wire 3
For example, it is manufactured by manganin (copper-manganese alloy) and constantan (copper-nickel alloy).

The superconducting wire 1 has a pair of superconducting flow paths 1a,
1b. These superconducting flow paths 1
a and 1b are twisted with each other at a constant pitch of 5 mm. As shown in FIG. 6, the superconducting wire 1 has a circular cross section and is made of a Cu—Ni or Cu base material 11, a large number of ultrafine Nb—Ti superconducting core wires 10 embedded therein, and an insulating material surrounding the base material 11. Consists of body 6.

In this embodiment, the diameter of the superconducting core wire 10 is 7 ± 0.2 μm, and one superconducting flow path 1a, 1
The number of superconducting core wires 10 used for b is 1106. The diameter of superconducting wire 1 is 0.3 mm. Preferably, the percentage of Ni in the Cu-Ni substrate is 5 to 35% by weight. In this embodiment, C
The percentage of Ni in the u-Ni substrate 11 is 3 by weight.
0%. Meanwhile, the percentage of Ti in the Nb-Ti core wire is preferably 40 to 50% by weight. In this embodiment, the Ti composition ratio of the Nb-Ti core wire is 50% by weight. The critical temperature of the Nb-Ti core wire is 9K, and the critical magnetic field is 12K at 4.2K.
T. The material of the superconducting core wire 10 is Nb3Sn
It is also possible to use

As shown in FIGS. 3 to 5, one end 1c of the superconducting flow paths 1a and 1b is connected to the other end 1c.
The superconducting flow paths 1a and 1b constitute an open loop-shaped superconducting wire 1. The superconducting channels 1a and 1b are connected to the plus terminal and the minus terminal of the external device, respectively, whereby current flows from the superconducting channels 1a to 1b.

As is understood from FIGS. 3 to 5, the insulator 6 must be a perfect insulator because current flows in the adjacent twisted superconducting flow paths 1a and 1b in opposite directions. is there.

The stranded superconducting wire 1 is wound around the winding shaft 2 approximately 40 times at a pitch of 0.7 mm or less. In this case, the ends 1 c of the superconducting flow paths 1 a and 1 b are in contact with the winding shaft 2. In the drawings, in order to clearly show the configuration of the superconducting switch, a gap is shown between each turn of the adjacent superconducting wire 1. However, in order to manufacture a compact superconducting switch, the superconducting wire 1 is It is desirable to wind without such a gap. It is expected that the winding pitch of the superconducting switch does not affect the electrical characteristics of the superconducting switch described later.

Furthermore, as indicated by a broken line in FIG. 3, and as shown in FIG. 5, the impregnating agent 4 for impregnating the liquid helium for cooling the superconducting wire 1, superconducting wire 1 are provided. The impregnating agent 4 entirely covers the cylindrical winding shaft 2 and the superconducting wire 1 except for the superconducting flow paths 1a and 1b, so that the end opposite to the end 1c is connected to an external device. doing.

The impregnating agent 4 must also be electrically insulating. Further, the impregnating agent 4 must suppress the wire movement of the superconducting wire 1. Therefore, the impregnating agent 4 is selected from an epoxy resin and a fat or oil. In this embodiment, an epoxy resin is used as the impregnating agent 4.

[0028] Thus, the insulator 6 constituting the outermost layer of the superconductive wire 1, should be good adhesion between the impregnant 4. Accordingly, the insulator 6 is selected from polyvinyl formal, polyamide imide, Kevlar (polyparaphenylene terephthalic acid monoamide) fiber, nylon fiber and the like. In this embodiment, polyvinyl formal is used as an insulator covering the superconducting wire 1.

Further , as shown in the broken line in FIG. 3 and in FIG. 5, the casing 5 is provided on the superconducting switch so as to surround the impregnating agent 4 in order to protect the impregnating agent 4 and the internal structure. Items and features required for the casing 5 are as follows.

The thermal conductivity of the casing, for thermal insulation of the superconducting switches during switch off, desirably low. Conversely, in order to rapidly cool the superconducting wire 1, it is desirable that the heat conductivity of the casing be high. Since it is impossible to satisfy these conflicting requirements at the same time, a compromise solution is needed. In view of the above, a phenolic resin based on a cotton cloth, an epoxy resin based on a glass cloth, or the like is used for the casing 5.

The twisted and returned to the cylindrical winding shaft 2 for winding the superconducting wire 1, the required items, features,
It is as follows.

The thermal conductivity of the winding shaft, for the thermal insulation of the superconducting switches during switch off, desirably low. Conversely, in order to rapidly cool the superconducting wire 1, it is desirable that the heat conductivity of the winding shaft be high. Since these conflicting requirements cannot be met at the same time, a compromise solution is required, as is the case 5. In view of the above, a phenolic resin based on a cotton cloth, an epoxy resin based on a glass cloth, or the like is used for the cylindrical winding shaft.

Furthermore, the thermal shrinkage of the cylindrical winding shaft 2 material is preferably smaller than that of the superconductive wire 1. Because, in this case, when the switch structure is cooled by liquid helium, the cylindrical winding shaft 2 does not shrink as much as the superconducting wire 1, and therefore, the superconducting wire 1 wound around the cylindrical winding shaft 2.
The tensile force inside increases. As a result, the stability of the superconducting wire on the cylindrical winding shaft 2 is improved. In other words, undesired slippage between the superconducting wire 1 and the cylindrical winding shaft 2 can be prevented, which contributes to suppression of the wire movement. Therefore, a quartz glass fiber reinforced epoxy resin or the like is suitable as the material of the columnar winding shaft 2. The heat shrinkage of the superconducting wire 1 between room temperature and 4.2 K (boiling point of liquid helium) is about 4 × 10 ^−4, and that of the quartz glass fiber reinforced epoxy resin is about 2 × 10 ⁻⁴ . This effect can be expected not only when the superconducting flow paths 1a and 1b are twisted with each other as in the embodiment. For example, even when this winding material is applied to the conventional structure shown in FIGS. 1 and 2, the effect of suppressing the wire movement can be expected.

In the structure of this embodiment, the resistance value of the superconducting switch in the open state (off state) is about 25Ω.

[0035] An experiment was conducted to examine the current performance of the superconducting switch. In this experiment, three samples were
6 were manufactured based on the above-described embodiment described with reference to FIG. 6, and for comparison, three samples were manufactured based on the prior art described with reference to FIGS. The difference between the sample of the embodiment and the sample of the prior art is only whether or not the superconducting flow paths 1a and 1b are twisted, and other characteristics, for example,
The dimensions and configuration are the same. In each of the six samples,
A current is applied four times, and the sample is in a normal conduction state (resistance state).
The current value transferred to was measured. FIG. 7 shows the results of the experiment. In the drawing, the vertical axis indicates the current value at which the sample has transitioned to the normal conduction state (resistance state), and the horizontal axis indicates the number of times of measurement. The open circles indicate the examples, and the black circles indicate the prior art. It can be clearly seen that the current-carrying performance is significantly improved in the sample based on the example.

In short, according to the above embodiment, even when the superconducting switch is exposed to a magnetic field from an external magnetic source, the superconducting flow paths 1a and 1b are twisted with each other, so that the superconducting flow paths 1a and 1b The electromagnetic forces generated in the opposite directions cancel each other out. Therefore, wire movement due to electromagnetic force can be suppressed.

[0037] As a result, the current performance of the superconducting switch is stable. That is, a large current close to the critical current of the superconducting wire can flow for a long time. Further, the improvement of the current-carrying performance and the ease of manufacturing the superconducting switch contribute to the manufacture of a lightweight and compact superconducting switch at low cost. Further, in this embodiment, since the wire movement is suppressed, the transition of the superconducting switch to a normal conduction state (resistance state) at an unexpected time is extremely reduced, and a highly reliable superconducting switch can be obtained.

[ Second Embodiment ] In the above embodiment, the superconducting wire 1 has a pair of superconducting flow paths 1.
a and 1b, but the present invention is not limited thereto. The above effect is due to the superconducting wire
Obviously, it will be obtained if it is constituted by a plurality of pairs of superconducting channels which are twisted together. In this case, the insulator 6 (outermost layer of the superconducting flow paths 1a and 1b)
Are provided separately in each of the superconducting flow paths 1a and 1b. Alternatively, it is also possible to bind the superconducting flow paths 1a and 1b having the same current flowing direction and to provide such an insulator 6 only between the superconducting flow paths 1a and 1b in the opposite directions. FIG. 8 shows a superconducting wire 1 according to a second embodiment of the present invention. In this embodiment, four superconducting channels 1
a, 1b (that is, two superconducting channels 1a and two superconducting channels 1b) are twisted at a constant pitch. In this case, the insulator 6 is provided separately.

The "third embodiment" Fig. 9 shows a third embodiment of the present invention. In this embodiment, each superconducting flow path 1a, 1b has a semicircular cross section. The superconducting flow paths 1a and 1b are
The wires a and 1b are twisted with each other so that the axial planes contact each other. In the drawings, reference numeral 7
Denotes a conductive portion (including a superconducting core wire and a base material) of the superconducting wire 1, and reference numeral 6 denotes an insulator that insulates the respective conducting portions 7 from each other.

[0040] With such a configuration, the entire superconducting wire 1
Are formed to have a circular cross section. Therefore, when the superconducting wire 1 is wound around the winding shaft 2 so as to form a superconducting switch as shown in FIGS. 3 to 5, the space factor of the superconducting core wire 10 of the superconducting wire 1 can be increased. In other words, this configuration contributes to the manufacture of a compact superconducting switch. Further, the superconducting flow path 1
a and 1b can be prevented from slipping with each other, further suppressing the wire movement. Moreover, the superconducting wire 1 of this embodiment has neither a concave portion nor a convex portion on the side surface. That is, the stability of the superconducting flow paths 1a and 1b in the winding shaft 2 is improved. Such a twisted open loop-shaped superconducting wire 1 is preferably formed by compression molding from the side after twisting the superconducting flow paths 1a and 1b. In this case, the space factor of superconducting portion 7 can be increased.

The "fourth embodiment" FIG. 10 is a perspective view of a fourth embodiment superconducting wire used in the superconducting switch according to an example of the present invention. This fourth embodiment is an improvement of the second embodiment shown in FIG. In this case, the conductive portion 7 (superconducting flow paths 1a, 1b)
Has the shape of a quarter fan of a circle. In the drawing, the superconducting flow paths 1a are arranged on diagonal lines of the cross section,
Superconducting flow path 1b is arranged on another diagonal line. This twisted open loop superconducting wire 1 is also
Preferably, after the superconducting flow paths 1a and 1b are twisted, they are formed by compression molding from the side.

In this embodiment, the same effects as in the third embodiment shown in FIG. 9 can be obtained. Furthermore, as a result of this configuration,
Since the four conductive portions 7 constitute a pair of superconducting wires 1, a pair of superconducting switches are formed around one cylindrical winding shaft 2.

The "Fifth Embodiment" FIG. 11 is a side view of a superconductive switch according to a fifth embodiment of the present invention, the heater wire 3, the impregnating agent 4, the casing 5
Are not shown. FIG. 12 is a sectional view taken from 12-12 in FIG.
13 shows a cross section of the superconducting wire 1 along the line, and FIG.
13 shows another cross section taken along line 13-13 of FIG. In this case, after a pair of superconducting flow paths 1a and 1b having a rectangular cross section are twisted with each other, the twisted open loop-shaped superconducting wire 1 is formed from the side so that the cross section of the superconducting wire 1 becomes square as a result. It is compression molded.

[0044] For example, as the section along the line 12-12 of Figure 11, with some parts, the superconducting current paths 1a, 1b
Have the same rectangular cross section, as shown in FIG. Also, in a certain portion, such as a portion along line 13-13 in FIG. 11, each superconducting flow channel 1a, 1b
As shown in FIG. 3, as a result of being twisted and then compression molded from the side, they are deformed to complement each other.

In such a configuration, the third configuration shown in FIG.
The same effect as that of the embodiment can be obtained. The superconducting wire 1 is
Because of the square cross section, one of the flat side surfaces of the superconducting wire 1 contacts the cylindrical winding shaft 2. Therefore, the stability of the superconducting wire 1 in the cylindrical winding shaft 2 is improved, and the wire movement is suppressed. Furthermore, the conductive portion 7 at each pitch
Is improved over the previous embodiment in which the superconducting wire has a circular cross section.

The "Sixth Embodiment" again, Figure 11 is a side view of a superconductive switch according to a sixth embodiment of the present invention. FIG. 14 shows a cross section of the superconducting wire 1 along the line 14-14 in FIG. 11, and FIG. 15 shows another cross section along the line 15-15 in FIG. The sixth embodiment is also an improvement of the second embodiment shown in FIG. In this case, two pairs of conductive portions 7 having a square cross section (superconducting flow path 1)
a, 1b) are twisted with each other, the twisted open loop-shaped superconducting wire 1 results in the superconducting wire 1
Is compression-molded from the side so that the cross section becomes square.

[0047] For example, as the section along the line 14-14 of Figure 11, with some parts, the superconducting current paths 1a, 1b
Have the same square cross section, as shown in FIG. In addition, as shown in FIG. 11, in a certain portion, such as a portion along the line 15-15 in FIG. 11, the superconducting flow paths 1a and 1b are twisted and then compression molded from the side as shown in FIG. , So that they complement each other.
In the drawing, the superconducting flow path 1a is arranged on a diagonal line of the cross section, and the superconducting flow path 1b is arranged on another diagonal line.

In such a configuration, the same effects as in the fifth embodiment shown in FIGS. 12 and 13 can be obtained.
Further, as a result of this configuration, since the four conductive portions 7 form a pair of superconducting wires 1, a pair of superconducting switches is formed on one winding shaft 2.

[0049] "Seventh Embodiment" Fig. 16 is a side view of a superconductive switch according to a seventh embodiment of the present invention. The seventh embodiment relates to an improvement of the first embodiment described with reference to FIGS. In the drawing, the illustration of the heater wire 3, the impregnating agent 4, and the casing 5 is omitted as in FIG. In this embodiment, the twisted superconducting wire 1 is covered with a covering adhesive tape 8 as a means for restraining the twisted superconducting wire 1 as shown in FIG. Although not shown, the adhesive tape 8 is porous. Therefore, the movement of the inner core wire 10 is further restricted. The covering tape 8 is provided with other mechanical restraining means, for example, a cloth, a net,
Strings, threads, fibers and the like can be substituted. Less than,
An alternative example of the seventh embodiment will be described.

[0050] "Eighth Embodiment" FIG. 17 is a side view of an eighth embodiment superconducting wire used in the superconducting switch according to an example of the present invention. In this example,
In each winding, superconducting wire 1 is restrained by net (fabric) 24.

[0051] "Ninth Embodiment" FIG. 18 is a side view of a ninth embodiment superconducting wire used in the superconducting switch according to an example of the present invention. In this example,
In order to suppress the twisted superconducting wire 1, the thread 22
Is wound around the twisted superconducting wire 1.

[0052] "Tenth Embodiment" FIG. 19 is a side view of a superconductive wire used in a superconductive switch according to a tenth embodiment of the present invention. In this embodiment, a thin adhesive tape 23 is wound around the twisted superconducting wire 1 in order to suppress the twisted superconducting wire 1.

[ Eleventh Embodiment ] FIG. 20 is a perspective view of a superconducting switch according to an eleventh embodiment of the present invention, in which the casing 5 is not shown.
In this embodiment, the impregnating agent 4 is covered by a restraining net 25 that restrains and suppresses the superconducting wire 1 twisted over the whole.

Although the embodiments of the present invention have been disclosed above, the present invention is not limited to the above embodiments, and various modifications, additions, and alternatives can be made without departing from the scope of the claims. Needless to say, there is.

[0055]

As is apparent from the above description, according to the superconducting switch of the first aspect of the present invention, even when the superconducting switch is exposed to a magnetic field from an external magnetic source, a pair of superconducting flow paths are provided. Are twisted with each other ,
The current flows through each of the superconducting channels forming the pair of superconducting channels.
Since the directions of the applied currents are opposite to each other, the opposite electromagnetic forces generated in the respective superconducting flow paths cancel each other. That is, in each twist, one superconducting channel suppresses movement of the other superconducting channel. Therefore, wire movement due to electromagnetic force can be suppressed.

[0056] As a result, the current performance of the superconducting switch is stable. That is, a large current close to the critical current of the superconducting wire can flow for a long time. Further, the improvement of the current-carrying performance and the ease of manufacturing the superconducting switch contribute to the manufacture of a lightweight and compact superconducting switch at low cost. Further, in this embodiment, since the wire movement is suppressed, the transition of the superconducting switch to a normal conduction state (resistance state) at an unexpected time is extremely reduced, and a highly reliable superconducting switch can be obtained.

Further , according to the superconducting switch of the second to seventh aspects, the space factor of the superconducting core wire in the superconducting wire can be increased. In other words, these configurations contribute to the manufacture of a compact superconducting switch.

[0058] According to the superconductive switch according to claim 8,
The mechanical restraining means, which is any of a tape, a cord, a thread, a net, and a fabric, further restrains the wire movement of the superconducting wire.

[0059] According to the superconductive switch according to claim 9 and 10, wherein switch structure, when it is cooled so that the superconducting state, the winding shaft does not shrink enough superconducting wire, wound in a superconducting wire in the winding shaft Increases the tensile force of As a result, the stability of the superconducting wire on the winding shaft is improved. In other words, it is possible to prevent an undesired slip between the superconducting wire and the winding shaft.

[Brief description of the drawings]

FIG. 1 is a perspective view of a conventional superconducting switch.

FIG. 2 is a side view of the superconducting switch of FIG. 1, omitting illustration of a heater wire, an impregnating agent, and a casing.

FIG. 3 is a perspective view of the superconducting switch according to the first embodiment of the present invention.

FIG. 4 is a side view of the superconducting switch of FIG. 3, omitting illustration of a heater wire, an impregnating agent, and a casing.

FIG. 5 is a detailed side view of the superconducting switch of FIG. 3;
The upper part is a sectional view.

FIG. 6 is a sectional view of a superconducting wire used for the superconducting switch of FIG. 3;

FIG. 7 is a graph comparing the current levels of the superconducting switch of the prior art (FIG. 1) and the superconducting switch of the present invention (FIG. 3) that transition from the superconducting state to the resistive state.

FIG. 8 is a perspective view of a pair of superconducting wires used in a superconducting switch according to a second embodiment of the present invention.

FIG. 9 is a perspective view showing a cross section of a superconducting wire used in a superconducting switch according to a third embodiment of the present invention.

FIG. 10 is a perspective view showing a cross section of a superconducting wire used for a superconducting switch according to a fourth embodiment of the present invention.

FIG. 11 is a side view of a superconducting switch according to a fifth embodiment and a sixth embodiment of the present invention, in which illustration of a heater wire, an impregnating agent, and a casing is omitted.

FIG. 12 is a sectional view of a superconducting wire used in a superconducting switch according to a fifth embodiment of the present invention, taken along line 12-12 of FIG.

13 is a cross-sectional view of the superconducting wire of FIG. 12 as viewed along line 13-13 of FIG.

FIG. 14 is a cross-sectional view of a superconducting wire used in a superconducting switch according to a sixth embodiment of the present invention, taken along line 14-14 in FIG.

FIG. 15 is a cross-sectional view of the superconducting wire of FIG. 14 taken along line 15-15 of FIG. 11;

FIG. 16 is a side view of a superconducting switch according to a seventh embodiment of the present invention, in which a heater wire, an impregnating agent, and a casing are not shown.

FIG. 17 is a side view of a superconducting wire used in a superconducting switch according to an eighth embodiment of the present invention.

FIG. 18 is a side view of a superconducting wire used for a superconducting switch according to a ninth embodiment of the present invention.

FIG. 19 is a side view of a superconducting wire used in a superconducting switch according to a tenth embodiment of the present invention.

FIG. 20 is a side view of a superconducting switch according to an eleventh embodiment of the present invention, in which a heater wire, an impregnating agent, and a casing are not shown.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 superconducting wire 1 a superconducting flow path 1 b superconducting flow path 2 winding shaft 8 coated adhesive tape (mechanical suppressing means) 22 thread (mechanical suppressing means) 23 adhesive tape (mechanical suppressing means) 24 mesh (fabric, mechanical suppression) Means) 25 Restricted net (mesh, cloth, mechanical restraining means).

Claims (10)

(57) [Claims] 1. A superconducting channel having at least a pair of superconducting channels wound around a winding shaft, the pair of superconducting channels constituting an open loop-shaped superconducting wire, and a current flowing through each superconducting channel is opposite to each other. In the superconducting switch that flows in the direction and reciprocates,
A superconducting switch, wherein the pair of superconducting flow paths are twisted with each other over the entire winding shaft. 2. The superconducting switch according to claim 1, wherein the superconducting wire has a rotationally symmetric cross-sectional shape, and each of the superconducting flow paths constitutes the superconducting wire with the rotationally symmetric cross-sectional shape. A superconducting switch having substantially the same cross-sectional area as an area divided by the number of superconducting channels. 3. The superconducting switch according to claim 2, wherein the superconducting wire has a circular cross-sectional shape, and each of the superconducting flow passages has the circular cross-sectional shape, the superconducting current constituting the superconducting wire. A superconducting switch having substantially the same cross-sectional area as the area divided by the number of roads. 4. The superconducting switch according to claim 3, wherein the cross section of each superconducting flow path is semicircular, and the semicircular plane portions of each superconducting flow path are opposed to each other. . 5. The superconducting switch according to claim 2, wherein the superconducting wire has a rectangular cross-sectional shape, and each of the superconducting flow paths has the rectangular cross-sectional shape, the superconducting current forming the superconducting wire. A superconducting switch having substantially the same cross-sectional area as the area divided by the number of roads. 6. The superconducting switch according to claim 5, wherein the superconducting wire has a square cross-sectional shape, and each of the superconducting flow passages has the square cross-sectional shape, the superconducting current constituting the superconducting wire. A superconducting switch having substantially the same cross-sectional area as the area divided by the number of roads. 7. The superconducting switch according to claim 2, wherein said superconducting wire is formed by compression from the side. 8. The superconducting switch according to claim 1, wherein the superconducting wire is provided with a tape, a string, a thread, and a cord for suppressing movement of each superconducting flow path.
A superconducting switch characterized in that the superconducting switch is suppressed by a mechanical suppressing means that is either a net or a fabric. 9. The superconducting switch according to claim 1, wherein said winding shaft is formed of a material having a smaller heat shrinkage than a superconducting wire. 10. The superconducting switch according to claim 9, wherein said winding shaft is formed of quartz glass fiber reinforced plastic.