JPH11191511A - Oxide superconducting current lead - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an oxide superconducting current lead from being damaged as far as possible, by a method wherein a first electrode and a second electrode are brought into contact with, fixed and bonded to, end parts of a plurality of rectangular oxide superconductor members which are arranged in a cylindrical shape by keeping intervals. SOLUTION: In an oxide superconducting current lead 4, a plurality of rectangular members 11 which are composed of an oxide superconductor are arranged in a cylindrical shape by keeping prescribed intervals. A discoidal electrode 2a and a discoidal electrode 2b which are composed of a material of good thermal conductivity and good electric conductivity, e.g. copper, and which comprise opening parts in their center are installed at end of the members 11. The members 11 are fixed to the electrodes 2a, 2b by using solder or silver paste. The rectangular members 11 which are composed of the oxide superconductor are arranged in the cylindrical shape by keeping the prescribed intervals. As a result, it is possible to prevent the thermal contraction difference between the members 11 and the electrodes 2a, 2b, and it is possible to ease concentration of a thermal stress. In addition, even when the plurality of members 11 are degraded partly, they can function as the superconducting current lead 4, and the current lead can be constituted so as to be of high safety and of high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxide superconducting current lead, and more particularly to a superconducting magnet device.

[0002]

2. Description of the Related Art At present, in various superconducting magnet devices, a superconducting current lead is indispensable for electrically connecting to an external device, and various superconducting current leads have been proposed so far. In recent years, as a means for reducing the amount of heat entering a refrigerant such as liquid helium or liquid hydrogen, an oxide superconducting current lead using an oxide superconductor having low thermal conductivity has been used.

The configuration of a superconducting magnet device using this oxide superconducting current lead will be described with reference to FIG.

First, the periphery of the superconducting magnet device 18 is constituted by a cryostat 19, and a superconducting magnet 20 is housed and mounted in the cryostat 19.
This superconducting magnet 20 is immersed and cooled in liquid helium 21. Further, there are a copper lead 22 connected to an external power supply outside the cryostat 19, and a liquid nitrogen tank 23 for inserting and cooling the copper lead 22. A tubular oxide superconducting current lead 15 is connected between a superconducting magnet 20 and a copper lead 22 immersed in a liquid nitrogen tank 23. In addition, there is a passage 24 for a refrigerant such as liquid nitrogen. In the passage 24 for the refrigerant, a refrigerant inlet and a refrigerant recovery port are provided.

FIG. 9 shows the structure of a conventional oxide superconducting current lead 15. The oxide superconducting current lead 15 has a configuration in which copper electrodes 2a and 2b are directly connected to both ends of a main body 1 made of a tubular oxide superconductor by solder or silver paste. The electrode 2a is a cryostat 19
The electrode 2b is connected to a superconducting magnet 20 via a flexible copper mesh wire or the like.

[0006]

The superconducting magnet device using the oxide superconducting current lead configured as described above greatly reduces the heat entering the liquid helium as compared with the configuration without the current lead. Can be done. This is because the thermal conductivity of the oxide superconductor is at least one order of magnitude smaller than that of copper, and no Joule heat is generated in proportion to the square of the flowing current in the superconducting state.

However, in a superconducting magnet device that handles an alternating current, a minute vibration is given to the oxide superconducting current lead by a mutual magnetic field effect. Also, it is difficult to avoid mechanical vibrations from outside during transportation. Furthermore, there is an extreme difference in thermal expansion between the main body 1 made of an oxide superconductor and the electrodes 2a and 2b made of a metal, and thermal stress concentration is likely to occur near the joint between the electrodes 2a and 2b. Oxide superconductors are different from various metals,
Generally, there is a possibility that damage such as cracks may occur due to structural weakness against bending force, impact and vibration. Damage such as cracks is a fatal defect for the oxide superconducting current lead, and has the problem of leading to damage to the superconducting magnet device.

The present invention has been made in view of the above circumstances, and has as its object to provide an oxide superconducting current lead that can prevent breakage as much as possible.

[0009]

An oxide superconducting current lead according to the present invention comprises a plurality of strip-shaped members made of an oxide superconductor, which are cylindrically arranged at intervals, and a plurality of strip-shaped members made of these oxide-shaped superconductors. And a first electrode and a second electrode that are disposed at an end and fixed so as to be electrically connected to the plurality of members.

[0010] The oxide superconducting current lead according to the present invention comprises:
A tubular main body made of an oxide superconductor, and first and second main bodies formed to respectively cover two ends of the main body.
And a protective resistor wound around the outer surface of the main body, one end of which is electrically connected to the first electrode, and the other end of which is electrically connected to the second electrode. It is characterized by being.

The oxide superconducting current lead according to the present invention comprises:
Radially arranged, a plurality of strip-shaped members made of an oxide superconductor, and arranged at the ends of these strip-shaped members, and fixed to be electrically connected to the plurality of members. And a first electrode and a second electrode.

The oxide superconducting current lead according to the present invention comprises:
A tubular main body made of an oxide superconductor, and first and second main bodies formed to respectively cover two ends of the main body.
And a connection end portion between the main body portion and the first and second electrodes is configured to have a continuous geometric shape.

[0013]

FIG. 1 shows the structure of a first embodiment of an oxide superconducting current lead 4 according to the present invention. The oxide superconducting current lead 4 of this embodiment has a main body 1 made of, for example, a tubular oxide superconductor, and electrodes 2a and 2b formed so as to cover both ends of the main body 1, respectively. ing.

The electrodes 2a, 2b are made of copper or the like having heat conductivity and electric conductivity, and are fixed to the main body 1 by solder or silver paste. The body 1 and the electrode 2
Assembly with a and 2b is performed at normal temperature. In addition, these electrodes 2 a and 2 b have a tapered shape at the end 3 of the connection portion with the main body 1. Therefore, the main body 1 and the electrode 2
Unlike the conventional case, the geometrical shape of the connection portion with a and 2b is continuous, and it is possible to reduce the mechanical concentration of mechanical stress. Further, since the connection portion has a continuous geometrical shape, it is possible to reduce an extreme difference in thermal expansion at the time of contact between the main body portion 1 and the electrodes 2a and 2b. Stress can be relieved.

Furthermore, at normal temperature, the oxide superconducting current lead 4
, The main body 1 and the electrodes 2a and 2b are displaced at a low temperature by thermal contraction. And
An excessive force is applied to the main body 1 and the connection between the main body 1 and the electrodes 2a and 2b. However, the tapered structure reduces the mechanical stress concentration, and an excessive force is applied to the oxide superconductor main body 1. Prevent it from acting. This prevents the main body 1 from being cracked or broken.

Next, the configuration of a second embodiment of the oxide superconducting current lead according to the present invention is shown in FIG. The oxide superconducting current lead 4 according to the second embodiment includes a tubular main body 1 made of an oxide superconductor and electrodes 2a and 2 made of a material having thermal and electrical conductivity, for example, copper.
b.

The electrode 2a is formed so as to cover one end of the main body 1. On the other hand, the electrode 2b has a hole at the bottom where the other end of the main body 1 is inserted, and has a cylindrical shape whose side surface covers the main body 1.

The electrodes 2a and 2b are fixed to the main body 1 by solder or silver paste. This fixing is performed at normal temperature. The end of the body 1 on the side where the electrode 2a is fixed is a free end.

For this reason, a guide 5 made of a heat insulating material for supporting the electrode 2a is formed at the end of the side surface of the electrode 2b.

Therefore, the end of the main body 1 on the side where the electrode 2a is fixed is not restrained in the axial direction, but is restrained in the direction perpendicular to the axis.

The outer surface of the electrode 2b is connected to the superconducting magnet device via the fixed electrode 6.

According to the second embodiment, the electrode 2a side of the main body portion 1 made of an oxide superconductor is applied to the superconducting magnet device even when an external force is applied to the superconducting magnet device during transportation or assembly, or even when vibration occurs. The free end alleviates the concentration of mechanical stress and prevents an excessive force from acting on the main body 1. This prevents the main body 1 made of the oxide superconductor from being cracked or broken.

Further, at normal temperature, the oxide superconducting current lead 4
At the low temperature, the main body 1 and the electrodes 2a and 2b made of an oxide superconductor are displaced by thermal contraction at a low temperature. Then, an excessive force is applied to the connection between the main body 1 and the electrodes 2a and 2b. However, since one end of the main body 1 is a free end, the concentration of mechanical stress is reduced, and the cracking of the main body 1 Prevents breakage.

Next, the structure of a third embodiment of the oxide superconducting current lead according to the present invention is shown in FIG. The oxide superconducting current lead 4 according to the third embodiment has an FRP (Fib) on the outer peripheral surface of the conventional oxide superconducting current lead 15 shown in FIG.
er Reinforced Plastic) 7. The FRP 7 has an outer surface of the main body 1 and the electrode 2.
a and 2b are fixed to the side surfaces by an adhesive or the like.

According to the present embodiment, the FRP 7 reduces the concentration of mechanical stress even when an external force is applied or vibration occurs during transportation or assembly of the superconducting magnet device, and the superconducting magnet device is made of an oxide superconductor. It prevents an excessive force from acting on the main body 1. This prevents the main body 1 from being cracked or broken.

Further, at normal temperature, the oxide superconducting current lead 4
At a low temperature, the body 1 made of an oxide superconductor and the electrodes 2a and 2b are displaced by thermal shrinkage. An excessive force is applied to the connection between the main body 1 and the electrodes 2a and 2b. However, the FRP 7 reduces the concentration of mechanical stress and prevents an excessive force from acting on the main body 1. This prevents the main body 1 from being cracked or broken.

Next, the structure of a fourth embodiment of the oxide superconducting current lead according to the present invention is shown in FIG. The oxide superconducting current lead 4 according to the fourth embodiment differs from the conventional oxide superconducting current lead 15 shown in FIG. 9 in that the corner 8 at the connection end between the main body 1 and the electrodes 2a and 2b is rounded, The geometrical shape of the part is made continuous.

With such a configuration, even when a force or vibration is externally applied to the oxide superconducting current lead 4 during transportation or assembly of the superconducting magnet device, mechanical stress concentration on the current lead 4 can be prevented. It is possible to prevent as much as possible, and it is possible to prevent cracks and the like of the main body 1 made of an oxide superconductor.

Further, cracks and the like due to heat shrinkage can be prevented. Next, a modification of the fourth embodiment will be described with reference to FIG. In this modified example, as shown in FIG. 5A, in the fourth embodiment, the surface roughness of the outer surface of the main body 1 is reduced as shown in FIG. It has a structured configuration. Even better effects can be obtained than in the case of the fourth embodiment.

Next, the structure of a fifth embodiment of the oxide superconducting current lead according to the present invention is shown in FIG. The oxide superconducting current lead 4 according to the fifth embodiment is obtained by spirally winding a protection resistor 9 having a circular cross section on the outer surface of the conventional oxide superconducting current lead 15 shown in FIG. FIG.
(A)). Note that one end of the protection resistor 9 is electrically connected to the electrode 2a, and the other end is electrically connected to the electrode 2b. The protection resistor 9 may have a plate shape as shown in FIG.

According to the fifth embodiment, since the outer surface of the main body 1 made of an oxide superconductor is protected by the protection resistor 9, the impact force and the vibration are directly reduced during transportation and assembly. Acting on the main body 1 can be prevented, and cracking of the main body 1 can be prevented.

Further, even if heat concentration due to local deterioration occurs in the main body 1 by bringing the protection resistor 9 into close contact with the main body 1, it is possible to release the heat to the protection resistor 9, thereby reducing heat concentration. Can be.

Even if the main body 1 is locally deteriorated, a part of the current can flow through the protection resistor 9 and the main body 1
Can be prevented from fusing.

Next, the configuration of a sixth embodiment of the oxide superconducting current lead according to the present invention is shown in FIG. The oxide superconducting current lead 4 of this embodiment has a configuration in which a plurality of strip-shaped members 11 made of an oxide superconductor are arranged in a cylindrical shape at predetermined intervals. At the ends of these members 11, disk-shaped electrodes 2a and 2b having a central opening made of a material having good thermal conductivity and electrical conductivity (eg, copper) are provided. The member 11 is fixed to the electrodes 2a and 2b using solder or silver paste.

According to the sixth embodiment, the strip-shaped members 11 made of an oxide superconductor are arranged in a cylindrical shape at predetermined intervals. This makes it possible to avoid a difference in heat shrinkage between the member 11 and the electrodes 2a, 2b.
Thermal stress concentration can be reduced.

Further, even if a part of the plurality of members 11 is deteriorated, it can function as a superconducting current lead, and the configuration is high in safety and reliability.

In the sixth embodiment, a plurality of strip-shaped members 11 made of an oxide superconductor are arranged in a cylindrical shape. However, as shown in FIG. An electrode 2a having a gear shape at both ends
The same effects as those of the sixth embodiment can be obtained even if they are fixed by the method described above. Note that in FIG.
The electrode provided at the other end of the is not shown.

[0038]

As described above, according to the present invention, breakage can be prevented as much as possible, and safety and reliability can be enhanced as much as possible.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the configuration of a first embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a second embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a configuration according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing a configuration of a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram of a modification of the fourth embodiment.

FIG. 6 is a schematic diagram showing the configuration of a fifth embodiment of the present invention.

FIG. 7 is an outline view showing a configuration of a sixth embodiment of the present invention.

FIG. 8 is a configuration diagram of a modification of the sixth embodiment.

FIG. 9 is a sectional view showing a configuration of a conventional oxide superconducting current lead.

FIG. 10 is a configuration diagram of a superconducting magnet device using an oxide superconducting current lead.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body part 2a, 2b Electrode 3 End part of connection part 4 Oxide superconducting current lead 5 Guide 6 Fixed side electrode 7 FRP 8 Corner part 9 Protective resistance 11 Strip member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shuntaro Hata 1 Komukai Toshiba Town, Saiwai-ku, Kawasaki City, Kanagawa Prefecture Inside the Toshiba R & D Center (72) Inventor Koji Kawauchi Komukai, Koyuki-ku, Kawasaki City, Kanagawa Prefecture Toshiba Town 1 Toshiba R & D Center (72) Inventor Yoshio Ohashi Yoshikazu Kawasaki City, Kanagawa Prefecture 1 Komukai Toshiba Town 1 Toshiba R & D Center (72) Inventor Ryo Sugawara Kanagawa Prefecture 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki City Toshiba R & D Center

Claims (4)

[Claims] 1. A plurality of strip-shaped members made of an oxide superconductor, which are cylindrically arranged at intervals, and are disposed at ends of these strip-shaped members to electrically connect with the plurality of members. And a first and a second electrode fixedly connected to the oxide superconducting current lead. 2. A tubular main body made of an oxide superconductor, first and second electrodes formed to respectively cover two ends of the main body, and a coil wound around an outer surface of the main body. An oxide superconducting current lead, comprising: a protection resistor electrically connected to the first electrode at one end and electrically connected to the second electrode at the other end. 3. A plurality of strip-shaped members made of an oxide superconductor radially arranged, and arranged at ends of these strip-shaped members so as to be electrically connected to the plurality of members. An oxide superconducting current lead, comprising: a first electrode and a second electrode fixed to the electrode. 4. A tubular main body made of an oxide superconductor, and first and second electrodes formed so as to cover two ends of the main body, respectively. An oxide superconducting current lead, wherein a connection end with the first and second electrodes is configured to have a continuous geometric shape.