JPH09219309A - Connection part of superconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a quenching phenomenon accompanied with an unbalanced current flowing in each wire of a connection part. SOLUTION: Untwisted wires 2a, 2b of superconductor wires 2A, 2B of twisted wires are connected in an outer periphery of a connection shaft 1 of a ceramic material. A plurality of slit grooves 1b having a U-shaped section are spaced equally in an axial direction in the outer periphery of the connection shaft 1. A thin metallized layer is formed in the outer periphery of the connection shaft 1, and the wires 2a, 2b are connected by solder under the state that they are freely engaged with a groove 1b. An end part of a truncated cone form is formed at both ends of the connection shaft 1 and it is possible to prevent the untwisted wires 2a, 2b from being abruptly bent when they are freely engaged with the groove 1b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting portion of a superconducting conductor for connecting ends of strands of a superconducting coil.

[0002]

2. Description of the Related Art Among conventional superconducting conductor connection parts,
For example, there is a connection portion shown in FIG. 9 disclosed in Japanese Patent Laid-Open No. 3-84903. In FIG. 9 (a) and FIG. 9 (b) showing an enlarged view of the arrow G in FIG. 9, a stranded superconducting wire 2A on the left side is shown.
As shown in FIG. 9B, the right ends of the pair of strands 2a constituting the wire are inserted into the trough-shaped sheath 6 having a U-shaped cross section, and the left ends of the pair of strands 2b constituting the right superconducting wire 2B are formed. Is also inserted into the sheath 6 and overlaps the strand 2a.

The sheath 6 is made of, for example, a copper material or an insulator, and the wires 2a and 2b inserted from both sides are connected by the solder injected into the inside of the sheath 6. Strand 2a,
In FIG. 9 (a), the pods 6 to which the pods 2b are connected are juxtaposed in six rows, and then the resin 7 is injected into the adjacent side of the pods 6 to be integrated as the connecting portion 2c1.

At the connecting portion of the superconducting conductor thus configured, the current flowing through each of the wires 2a and 2b fluctuates,
When the magnetic field fluctuates due to this fluctuating current, a slight eddy current flows in each connecting portion 2c1.

However, the value is suppressed by the resin 7 interposed between the sheaths 6.

Further, in Japanese Patent Laid-Open No. 3-84903, as shown in FIG. 10, a sheath 6A formed in a gutter shape from a copper plate is adopted at the connecting portion of the wires 2a and 2b, and each sheath 6A is, for example, ,
A connection portion of a superconducting conductor supported by a connection base 8 made of a high resistance metal material such as austenitic thin stainless steel is also disclosed.

In this case, the solder 3 for brazing the wires 2a, 2b is also joined to the sheath 6A, so that the mechanical strength of the joint is high and the joint area is wide. Not only can it be reduced, but it can also be easily fixed to the connection base 8.

Further, FIG. 11 is also a connection portion of the superconducting conductor disclosed in the above-mentioned Japanese Patent Laid-Open No. 3-84903, in which the sheath 6A shown in FIG. 10 is omitted and each of the strands 2a and 2b is connected to the connection base 8. After being inserted into the formed U-shaped groove, it is connected by soldering.

[0009]

[Problems to be solved by the invention]
In the connecting portion of the superconducting conductor shown in FIG. 9, each sheath 6
It is troublesome to inject the resin to the side adjacent to.
For example, in order to prevent the resin flowing out from both ends of each sheath 6, it is necessary to seal the voids formed between both ends of each sheath 6 and each of the strands 2a and 2b with a filler in advance. Don't

Further, in any of FIGS. 9, 10 and 11, the wires 2a and 2b at the front and rear ends must be bent outward in order to be inserted into the sheath 6, so that the joint portion inside the sheath 6 can be obtained. The overlapping length may differ from that of the central wires 2a and 2b.

In order to avoid this condition, the ends of the wires other than the wires 2a and 2b located on the outermost sides must be cut off. Moreover, the length of the cut portion must be gradually increased toward the central portion.

In order to insert the stranded superconducting wires 2A and 2B into the sheath 6 from the ends thereof, a single wire portion is formed in an arc shape from the untwisted portion to the end of the sheath 6. Therefore, if the strands vibrate due to electromagnetic force, etc., there is a risk of transition to the normal conducting state (hereinafter referred to as quench).

Further, the current flowing through each of the strands is concentrated on the outermost strand of the strands of the flat plate-shaped connecting portion,
The temperature of the outer connection rises, which can also lead to a quench. Then, the objective of this invention is to prevent the imbalance of the electric current which flows into each strand, and to obtain the connection part of the superconducting conductor which can eliminate the fear of quenching.

[0014]

According to a first aspect of the present invention, there is provided a connecting portion of a superconducting conductor, wherein a plurality of grooves are formed in the axial direction of the outer circumference and the metal film is formed on both sides of the groove of the insulating rod. It is characterized in that the connecting end of the wire is inserted and connected to the metal coating with a bonding material.

In the connecting portion of the superconducting conductor according to the second aspect of the invention, an annular groove is formed in the outer periphery of the intermediate portion of the insulating rod in the direction orthogonal to the axial direction, and is connected to the superconducting wire with a bonding material. It is characterized in that a pair of short-circuit rings are inserted into the groove.

Further, the connecting portion of the superconducting conductor of the invention described in claim 3 is characterized in that tapered portions are formed at both ends of the insulating rod.

Further, the connecting portion of the superconducting conductor of the invention described in claim 4 is characterized in that the insulating rod is made of a ceramic material.

Further, the connecting portion of the superconducting conductor of the invention described in claim 5 is characterized in that a plurality of grooves formed in the axial direction are equally spaced from the outer circumference of the insulating rod.

By such means, in the invention described in claim 1, the eddy current due to the magnetic flux generated by the current flowing through the superconducting conductor is suppressed by the insulating rod and the thin metal film.

Further, in the invention described in claim 2,
The insulating rod and the metal coating suppress the eddy current and make the current value flowing through each superconducting conductor uniform by the short-circuit ring.

Further, in the invention according to claim 3,
The insulating rod and the metal coating suppress eddy currents and reduce the curvature of the superconducting conductor at both ends of the insulating rod.

In the invention described in claim 4,
The insulating rod and the metal coating suppress the eddy current and maintain the strength of the connection portion in a cryogenic state.

Further, in the invention according to the fifth aspect, the energization conditions at the connecting portions of the currents flowing through the respective superconducting conductors are equalized.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a connecting portion of a superconducting conductor of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of a connecting portion of a superconducting conductor of the present invention, and corresponds to FIGS. 9, 10 and 11 shown in the prior art.

In FIG. 1, strands 2a and 2b at the ends of superconducting wires 2A and 2B are groove portions 1b formed on the outer periphery of a connecting shaft 1 made of ceramics such as alumina or alumina nitride, which is formed in a substantially columnar shape. Inserted and connected as described below. In addition, in FIG. 1, in order to avoid complication of the figure on the drawing, the case of a super electric wire composed of four strands is shown, but in the actual product, it is 12 or more, for example.

That is, FIG. 1A and FIG. 1A
1 (b) showing a sectional view taken along line AA of FIG. 1 and FIG. 1 (c) showing a partially enlarged detailed view of FIG. 1 (b), the connecting shaft 1 has a truncated cone-shaped end portion. 1a is formed at both ends, and a cross section is formed on the outer periphery of the cylindrical portion between these end portions 1a as shown in FIG.
As shown in (a) and (b), four U-shaped groove portions 1b
Are formed at 90 ° intervals in the axial direction before the firing step.

FIG. 2 is an enlarged detailed view of the connecting shaft 1 shown in FIG. 1, and FIG. 3 is a sectional view taken along line BB of FIG. 2 and 3
In the outer periphery of the connecting shaft 1, a metallized layer 4 shown by a chain double-dashed line is formed including the groove portion 1b except the end surface of the end portion 1a.

The metallized layer 4 is formed by brushing the connecting shaft 1 with powder of molybdenum and manganese in a thickness of about 10 to 20 μm, inserting it into a high temperature furnace and baking it, and nickel plating is applied to this surface to the maximum extent. The thickness is 5 μm.

Connection shaft 1 having this metallized layer 4 formed
1, the strands 2a and 2b of the superconducting wires 2A and 2B, which are untwisted from the twisted portions, are inserted from the end portion 1a side, respectively.
As shown in FIG.
The connection portion 2c shown in (a) is formed.

Next, the operation of the connecting portion of the superconducting conductor thus configured will be described with reference to FIG. 4 and FIG. 5 showing an enlarged detailed view of the portion C of FIG. 4 and 5, the shape of the groove into which the strand 2a (2b) is inserted is drawn as an explanatory diagram and is different from FIG.

In FIG. 4 and FIG. 5, the wire 1a of the connecting shaft 1 is formed by the current shown by the arrow D in the wire 2a joined via the solder 3 to the groove 1b formed on the outer periphery of the connecting wire 1. In the surroundings, a counterclockwise magnetic flux is generated in FIGS. 4 and 5 indicated by arrow E.

However, since the magnetic flux indicated by the arrow E vortexes, except for the thin metallized layer 4, through the connecting shaft 1 between the space outside the wire 2a and the inside ceramic material, no eddy current flows. Therefore, heat generation due to this eddy current can be prevented, and quenching of the connection portion due to this heat can be avoided.

Next, FIG. 6 is a view showing a second embodiment of the connecting portion of the superconducting conductor of the present invention, which corresponds to FIG. 1 and corresponds to claim 2, and FIG. FIG. 8 is an enlarged detailed view of a vertical cross section of the connecting shaft, which corresponds to FIG. 2, and FIG.
FIG. 4 is a sectional view taken along line F, corresponding to FIG. 3.

6, FIG. 7 and FIG.
3 is different from FIG. 3 in that a part of the shape of the connecting shaft and a balance ring for equalizing the current flowing through the strands are provided, and other points are the same as those in FIGS. 1, 2 and 3. is there. Therefore, the same elements as those in FIG. 1, FIG. 2 and FIG.

That is, the connecting shaft 1 shown in FIGS. 6 and 7.
The outer shape of A is the same as that of the connecting shaft 1 shown in FIGS. 1, 2 and 3, but a groove 1c having a U-shaped cross section is formed in an annular shape in the central portion in a direction orthogonal to the axis. ing.

The metallization layer 4 shown in FIGS. 2 and 3 is also formed in the groove 1c together with the four grooves 1b. As shown in FIG. 8, an arc-shaped balance ring 5 made of a copper material is inserted into the groove 1c from both sides and brazed.

The thickness of the balance ring 5 is the same as the depth of the groove 1c to the bottom surface of the groove portion 1b.
The outer surface of the inserted balance ring 5 is flush with the bottom of the groove 1b.

In the connecting portion of the superconducting conductor having the above-mentioned structure, not only the wires 2a on one side and the wires 2b on the other side are brazed in the groove portion 1b, but also the connecting portion is connected by the balance ring 5. Since the lines 2c are respectively short-circuited, the imbalance of the currents flowing through the individual wires can be eliminated.

Therefore, since it is possible to prevent the temperature rise of the specific wire, it is possible to eliminate the risk of quenching, and it is possible to stably maintain the superconducting state of the superconducting coil during operation. Further, the cutting process for aligning the positions of the tips of the strands, which is necessary in the case of FIG. 9 shown in the conventional technique, can be omitted.

In the above embodiment, the groove portion 1b formed on the connecting shafts 1 and 1A has been described in the case of four threads, but as described above, it is a diagram for preventing the complexion of the figure, and actually it is a figure. The required number of groove portions 1b may be formed by changing the diameter of the connecting shafts 1 and 1A and the distance between the grooves.

The end portion 1a of each of the connecting shafts 1 and 1A has a taper shape in which the diameter of the end portion is about ½ of the diameter of the bottom portion, but in addition to the base portion of the untwisted portion of the wires 1a and 1b. If there is a risk of deformation due to the generated electromagnetic force, the ends may be further extended to have a small diameter and the number of joints between the wires 2a and 2b and the metallized layer 4 may be increased. The length of the tapered portion may be determined depending on the operating conditions of the superconducting device in which the connecting portion of the superconductor is adopted. Also, the connecting shaft 1, 1A
On the other hand, a shallow groove may be formed in the axial direction, and the strands 1a and 1b may be provided in the groove.

Although the connecting shafts 1 and 1A are made of a ceramic material in the above embodiment, they may be made of quartz glass, and the surface of the metallized layer 4 is nickel-plated, but may be made of copper. Although the thickness is set to 5 μm, it may be 1 μm.

Further, in the above embodiment, the connecting shafts 1, 1A
The shape of is a round bar, but a polygonal bar may be used. Further, although a solid rod is used in the above embodiment, a hollow rod may be used. Furthermore, although an example in which two strands are inserted into the groove 1b into which the strands 1a and 1b are inserted has been described, two strands are inserted from both sides,
A total of four may be used, or they may be stacked one above the other.

[0044]

As described above, according to the first aspect of the present invention,
Vortices generated by the magnetic flux generated by the current flowing through the superconducting conductor are obtained by inserting the connecting end of the wire into the groove of the insulating rod on which the metal coating is formed by forming multiple grooves in the axial direction of the outer circumference and connecting it with a bonding material. Since the electric current is suppressed by the insulating rod and the thin metal film, it is possible to obtain the superconducting conductor connecting portion which can prevent the imbalance of the electric currents flowing through the individual wires and eliminate the risk of quenching.

According to the second aspect of the invention, a pair of short-circuit rings are formed on the outer periphery of the intermediate portion of the insulating rod in the form of an annular groove in the direction orthogonal to the axial direction and are connected to the superconducting wire by a connecting material. By inserting into the groove, the eddy current is suppressed by the insulating rod and the metal coating, and the current value flowing in each superconducting conductor is
Since it is made uniform by the short-circuit ring, it is possible to obtain a connection portion of the superconducting conductor which can prevent the imbalance of the currents flowing through the individual wires and eliminate the risk of quenching.

According to the third aspect of the present invention, by forming the tapered portions at both ends of the insulating rod, the insulating rod and the metal coating suppress the eddy current, and the superconducting conductors at both ends of the insulating rod are suppressed. Since the bending is relaxed, it is possible to obtain the connection portion of the superconducting conductor which can prevent the imbalance of the currents flowing through the individual wires and eliminate the risk of quenching.

According to the invention of claim 4, the insulating rod is made of a ceramic material, so that the insulating rod and the metal film suppress the eddy current and maintain the strength of the connecting portion in a cryogenic state. Therefore, it is possible to obtain the connection portion of the superconducting conductor which can prevent the imbalance of the currents flowing through the individual wires and eliminate the risk of quenching.

Further, according to the invention of claim 5,
By arranging the multiple grooves formed on the outer circumference of the insulating rod at equal intervals, the energization conditions at the connection part of the current flowing through each superconducting conductor were made uniform, so that the imbalance of the current flowing through each strand was prevented, It is possible to obtain the connection portion of the superconducting conductor that can eliminate the possibility of quenching.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a connecting portion of a superconducting conductor of the present invention, (a) is an overall view, and (b) is an A- line in (a).
A sectional view, (c) is a partially enlarged view of (b).

FIG. 2 is a partially enlarged detailed vertical view of FIG.

3 is a sectional view taken along line BB of FIG.

FIG. 4 is a partial perspective view showing the operation of the first embodiment of the connecting portion of the superconducting conductor of the present invention.

FIG. 5 is an enlarged detailed view showing a C portion of FIG.

FIG. 6 is a diagram showing a second embodiment of the connection portion of the superconducting conductor of the present invention.

7 is a partially enlarged vertical sectional view of FIG.

FIG. 8 is a sectional view taken along line FF of FIG. 7;

FIG. 9 is a plan view showing an example of a connection portion of a conventional superconducting conductor.

FIG. 10 is a cross-sectional view showing an example of a connection portion of a conventional superconducting conductor.

11 is a sectional view showing an example of a conventional superconducting conductor, which is different from FIG.

[Explanation of symbols]

1, 1A ... Connection shaft, 1a ... End portion, 1b, 1c ... Groove portion, 2
A, 2B ... Superconducting wire, 2a, 2b ... Elemental wire, 2c ... Connection part, 3 ... Solder, 4 ... Metallized layer, 5 ... Balance ring.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takeshi Okuma 4-1 Egasaki-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture, Tokyo Electric Power Technology Laboratory (72) Inventor Jun Matsuzaki, 1 Toshiba-cho, Fuchu, Tokyo Address: Toshiba Fuchu factory (72) Inventor ▲ Tsuru ▼ Kazuyuki Eiichi Kazuyuki Toshiba Town, Fuchu-shi, Tokyo Address: Toshiba Fuchu factory (72) Inventor Takashi Yazawa 1 Komukai Toshiba-cho, Kawasaki-shi, Kanagawa Address Incorporated company Toshiba Research and Development Center (72) Inventor Shunji Nomura 1 Komukai Toshiba-cho, Kawasaki City, Kanagawa Prefecture Incorporated Company Toshiba Research and Development Center

Claims (5)

[Claims] 1. An insulating rod in which a plurality of grooves are formed in the axial direction of the outer periphery and a metal coating is formed, and a superconducting wire in which connecting ends are inserted into the groove from both sides of the insulating rod and connected by a bonding material. The connecting part of the superconducting conductor. 2. An annular groove is formed in an outer periphery of an intermediate portion of the insulating rod in a direction orthogonal to an axial direction, and a pair of short-circuit rings connected to the superconducting wire by a bonding material is inserted into the groove. The connecting portion of the superconducting conductor according to claim 1. 3. The connection portion of the superconducting conductor according to claim 1, wherein tapered portions are formed at both ends of the insulating rod. 4. The superconducting conductor connecting portion according to claim 1, wherein the insulating rod is made of a ceramic material. 5. The method according to claim 1, wherein the plurality of grooves are formed on the outer circumference of the insulating rod at equal intervals.
The connection part of the superconducting conductor according to any one of 1.