JPH0616367B2 - Superconducting conductor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting conductor, and more particularly to a superconducting conductor suitable for use as a coil conductor of a large-sized high magnetic field magnet.

[Background of the Invention]

As shown in FIG. 5, a superconducting conductor having a large capacity with a rated current exceeding 1000 amperes has a storage groove 1a formed in the longitudinal direction so that the cross-sectional shape in the direction perpendicular to the longitudinal direction is a gate shape. among constructed of a high-purity copper stabilizing material 1 of the receiving groove 1a, the superconducting material 2 consisting of solid or stranded superconducting wire, such as Nb-Ti or Nb ₃ Sn, extrusion or drawing high purity A bypass conductor 5 having a copper coating layer 4 provided on the surface of the aluminum stabilizing material 3 and a stabilizing material lid 6 made of high-purity copper are sequentially fitted and fixed by a soldering layer 7. , High-purity copper stabilizer 1
A rough surface 1b for enhancing the cooling effect is formed by projections and depressions by shot blasting or cutting.

Further, as shown in FIG. 6, the bypass conductor 5 having the copper coating layer 4 formed on the surface of the high-purity aluminum stabilizing material 3 is also used as a lid, so that the high-purity copper stabilizing material lid 6 described above is used. May be omitted.

By the way, such a superconducting conductor is cooled to an extremely low temperature (4.2 K) by using liquid helium as a refrigerant to keep the superconducting material 2 in a superconducting state. However, the behavior of the superconducting material 2 due to the generated magnetic field or disturbance such as a fluctuating magnetic field is disturbed. As a result, a phenomenon occurs in which the superconducting state is partially broken and the state changes to the normal conducting state. In a large magnet with a high magnetic field, since the accumulated energy is large, if such a transition spreads throughout the coil (quenching phenomenon), there is a risk that the coil will be burned or the helium container will be damaged due to an increase in pressure. For this reason, normally, even if a partial normal conduction state occurs, which is called complete stabilization, the amount of cooling heat by liquid helium is larger than the amount of heat generated by it, so that the quench phenomenon does not occur. It

For that purpose, when a part of the superconducting material 2 is transferred to the normal conducting state, it is desirable to reduce the amount of heat generated in the part as much as possible, and the high-purity copper stabilizing material 1 and the high-purity aluminum stabilizing material are preferable. 3 and the high-purity copper stabilizing material lid 6 serve to reduce the amount of heat generated by bypassing the current in the portion where the superconducting material 2 has transitioned to the normal conducting state and has reached a high resistance value. Electric resistance of the superconducting material such as Nb-Ti or Nb ₃ Sn is a normal conducting form show a very high value. On the other hand, the electric resistance of high-purity copper and high-purity aluminum is extremely low at extremely low temperatures, and the volume resistivity of high-purity aluminum is a fraction of that of high-purity copper. When the superconducting material is placed in parallel with the superconducting material as a stabilizing material, the superconducting material partially enters the normal conducting state and the electric resistance increases, so that the current in the portion is bypassed to the stabilizing material to reduce the generation of jail heat.

However, high-purity aluminum has low rigidity and has a property that the volume resistivity remarkably increases when subjected to processing strain. When a coil is formed by winding a superconducting conductor using such high-purity aluminum as a stabilizer, an electromagnetic force W as shown in FIGS. 5 and 6 acts on the superconducting conductor to The conductor is compressed. Then, when this electromagnetic force W is transmitted to the high-purity aluminum stabilizing material 3, the high-purity aluminum stabilizing material 3 is work-hardened to increase the volume resistivity, and the performance as the stabilizing material deteriorates. is there.

Such a superconducting conductor is disclosed in JP-A-59-9809.

[Object of the Invention]

Therefore, an object of the present invention is to protect the high-purity aluminum stabilizing material used as a bypass conductor from an external force such as an electromagnetic force acting on the superconducting conductor, thereby reducing the occurrence of processing strain and increasing the volume resistivity. To alleviate.

[Outline of Invention]

In order to achieve this object, the present invention, in the portion corresponding to the storage position of the high-purity aluminum stabilizer in both legs of the high-purity copper stabilizer, such as a groove or cavity extending in the longitudinal direction of the superconducting conductor. By providing the space portion, it is possible to reduce the transmission of the external force acting from the both side leg portions to the high-purity aluminum stabilizing material, and reduce the occurrence of processing strain of the high-purity aluminum stabilizing material. To do.

Example of Invention

FIG. 1 shows a cross section of a coil formed by winding a superconducting conductor according to the present invention. The superconducting conductor of this embodiment is of the same type as that of the conventional superconducting state shown in FIG. 5, and the superconducting material 2 and A high-purity aluminum stabilizing material 3 having a copper coating layer 4 and a high-purity copper stabilizing material lid 6 are stored,
It has a structure in which it is joined and fixed by the soldering layer 7. Grooves 81 and 82 corresponding to the space portions of the present invention are formed on the outer surfaces of both side leg portions 1c and 1d of the high purity copper stabilizing material 1. The grooves 81 and 82 are provided to reduce the pressure hardening of the high-purity aluminum stabilizing material 3 due to the electromagnetic force W acting on the superconducting conductor. Is formed so as to extend in the longitudinal direction of the conductor. The grooves 81 and 82 are also used as passages of liquid helium for cooling the superconducting conductor,
Therefore, in order to increase the heat transfer area, fine grooves 81a and 82a are further formed at the bottoms of the grooves 81 and 82.

The superconducting conductor configured as described above is wound in the longitudinal direction via the partial insulating spacers 9 and 10 to form a coil.

The coil composed of the superconducting conductor as described above is immersed in cryogenic liquid helium to be cooled. At this time, liquid helium flows into the grooves 81 and 82 through the gap between the adjacent superconducting conductors and flows along the grooves in the longitudinal direction of the conductor. Since the insulating spacers 9 and 10 are partially present on the side surface of the superconducting conductor, the intervening regions of the insulating spacers 9 and 10 cannot contact with liquid helium, and cooling heat transfer is hindered. But,
Since there is no contact with the insulating spacers 9 and 10 at the grooves 81 and 82, a large heat transfer area can be secured in combination with the provision of the thin grooves 81a and 82a. Moreover, since the flow of liquid helium becomes smooth in the grooves 81, 82, even if helium gas is generated due to the temperature rise of the conductor, its discharge becomes smooth, and the grooves 81, 82 make a great contribution to the cooling action. To do.

On the other hand, when the superconducting conductor is in the superconducting state and the coil is in the operating state, an electromagnetic force W in the suction direction is generated between the adjacent superconducting materials due to the current flowing in the superconducting material 2. This electromagnetic force W acts on each conductor as a compressive force in each superconducting conductor. However, according to the superconducting conductor of the present invention, the grooves 8 are formed in the legs 1c and 1d of the high-purity copper stabilizer 1 in the direction in which the compressive force acts on the high-purity aluminum stabilizer 3.
Since 1,82 are formed, this compressive force will be concentrated on the part avoiding the grooves 81,82, that is, the part avoiding the high-purity aluminum stabilizing material 3, and mainly the high-purity copper stabilizing member. It will be received by the top 1e of 1 and the stabilizer cover 6.
As a result, the compressive force transmitted to the high-purity aluminum stabilizing material 3 is reduced, and accordingly, the processing strain of the high-purity aluminum stabilizing material 3 is reduced and the deterioration of the performance as the stabilizing material is reduced.

The superconducting conductor shown in FIG. 2 is an embodiment devised so as to protect the high-purity aluminum stabilizing material 3 from an external force W acting from above, below, left and right. In this example, the portions for reducing the external force acting on the high-purity aluminum stabilizing material 3 are the grooves 81, 82 on the outer surface of the side legs 1c, 1d of the high-purity copper stabilizing material 1 and the top portion. It is constituted by a groove 83 on the outer surface of 1e and a groove 84 formed at the open end of the storage groove 1a by stopping the stabilizing material lid 6 at a position lower than the tips of the legs 1c, 1d.

When an external force W in the left-right direction acts on this superconducting conductor, this external force is concentrated on the top 1e of the high-purity copper stabilizing material 1 and the stabilizing material lid 6 due to the grooves 81 and 82, as in the above-mentioned embodiment. Will be transmitted. When the vertical external force W is applied, this external force is concentrated and transmitted to the legs 1c and 1d due to the grooves 83 and 84. Therefore, this superconducting conductor can reduce the processing strain of the high-purity aluminum stabilizing material 3 due to the external force W acting from the vertical and horizontal directions.

In the embodiment shown in FIG. 3, cavities 85 to 88 are provided in place of the grooves 81 and 82 as the space portions in the above embodiment.
The cavities 85, 86 are formed in the legs 1c, 1d of the high-purity copper stabilizing material 1 by extending in the longitudinal direction of the conductor corresponding to the high-purity aluminum stabilizing material 3. The cavity 87 is formed in the top portion 1e of the high-purity copper stabilizing material 1 so as to extend in the longitudinal direction corresponding to the storage groove 1a, and the cavity 88 is formed in the stabilizing material lid 6 so as to extend in the longitudinal direction. To be done. Liquid helium for cooling the superconducting conductor is supplied to the periphery of the conductor and the cavities 85 to 88.

When an external force W acts on this superconducting conductor, the transmission of the force inside the conductor is blocked in the cavities 85 to 88, so this external force concentrates on members other than the high-purity aluminum stabilizing material, and The extent to which the aluminum stabilizing material 3 is reached to cause processing strain in the stabilizing material is reduced.

The embodiment shown in FIG. 4 is of the same type as the conventional superconducting conductor shown in FIG. 6, and is an example devised to protect the high-purity aluminum stabilizing material 3 from an external force W in the left-right direction. In this example, the space portion for protecting the high-purity aluminum stabilizing material 3 is constituted by the step portions 89, 90 on the outer surfaces of the both-side legs 1c, 1d of the high-purity copper stabilizing material 1. These steps 89, 90 are also made of high-purity aluminum stabilizing material 3
Corresponding to, it extends in the longitudinal direction and is formed at a lower position than other surfaces.

Therefore, also in this superconducting conductor, the external force W acting from the left-right direction is concentrated and transmitted to the members other than the high-purity aluminum stabilizing material 3 from the portions other than the step portions 89, 90, and the high-purity aluminum. The processing strain of the stabilizing material 3 is reduced.

Incidentally, in the embodiment shown in FIGS. 2 to 4, the grooves 81 to 84 for forming the space portion, the cavities 85 to 89, and the step portions 89 and 90.
If the same thin groove as that of the embodiment shown in FIG. 1 is formed on the surface of, the cooling effect is further improved.

Further, the space portion can be formed by arbitrarily combining grooves, cavities, step portions or other shapes depending on the form of the superconducting conductor.

〔The invention's effect〕

As described above, the present invention has a space portion such as a groove or a cavity extending in the longitudinal direction of the superconducting conductor in the portion corresponding to the storage position of the high-purity aluminum stabilizing material on both side legs of the high-purity copper stabilizing material. Since it is provided so that the external force acting from both side leg parts is transmitted to the high-purity aluminum stabilizing material, it is possible to reduce the occurrence of processing strain of the high-purity aluminum stabilizing material. The increase in the volume resistivity can be reduced.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention. FIG. 1 is a sectional view of a coil using a superconducting conductor according to the present invention, and FIGS. 2 to 4 are other embodiments. It is sectional drawing of the superconducting conductor shown, and FIG. 5 and FIG. 6 are sectional drawings of the conventional superconducting conductor. 1 ... High-purity copper stabilizing material, 1a ... Storage groove, 2 ... Superconducting material, 3 ... High-purity aluminum stabilizing material, 7 ... Soldering layer, 81, 82 ... Grooves forming space .

Continuation of front page (56) Reference JP-A-53-56994 (JP, A) JP-A-54-64994 (JP, A) JP-A-56-73807 (JP, A) JP-A-56-134410 (JP , A) JP 58-172813 (JP, A) JP 59-9809 (JP, A) JP 59-105211 (JP, A) Actual development S54-177577 (JP, U) Actual development 61-76630 (JP, U) JP-B 43-16030 (JP, B1) US Patent 4079187 (US, A)

Claims (7)

[Claims] 1. A high-purity copper stable cross-sectional shape cut at a right angle to the longitudinal direction by a storage groove 1a extending in the longitudinal direction and having a gate shape composed of both side leg portions 1c, 1d and a top portion 1e. In a superconducting conductor comprising a chemical material 1, a superconducting material 2 which is lined up in the storage groove 1a and soldered 7 and a high-purity aluminum stabilizing material 3,
An external force acting from the side leg portions 1c, 1d is applied to the portions of the leg portions 1c, 1d of the high-purity copper stabilizing material 1 corresponding to the storage positions of the high-purity aluminum stabilizing material 3 to stabilize the high-purity aluminum stabilizing material 1. A superconducting conductor, characterized in that spaces 81, 82 or 85, 86 or 89, 90 extending in the longitudinal direction of the superconducting conductor for reducing transmission to the chemical material 3 are provided. 2. In the first aspect of the invention, the space portion is constituted by grooves 81, 82 formed on the outer surfaces of the side legs 1c, 1d of the high-purity copper stabilizing material 1. Characteristic superconducting conductor. 3. The claim 1 according to claim 1, wherein the space portion is constituted by step portions 89, 90 formed on the outer surfaces of the side legs 1c, 1d of the high-purity copper stabilizing material 1. Is a superconducting conductor. 4. The space according to claim 1, wherein the space is constituted by cavities 85 and 86 formed in members of both side legs 1c and 1d of the high-purity copper stabilizing material 1. A superconducting conductor characterized in that 5. The high-purity copper stabilizing material 1 according to claim 1, wherein a portion corresponding to a storage position of the high-purity aluminum stabilizing material 3 in the top portion 1e of the high-purity copper stabilizing material 1 acts from the top portion 1e side. A superconducting conductor, characterized in that spaces 83, 87 extending in the longitudinal direction of the superconducting conductor for reducing the transmission of external force to the high-purity aluminum stabilizing material 3 are provided. 6. The stabilizer cover 6 according to claim 1, wherein the stabilizer cover 6 is provided on the opening side of the storage groove 1a of the high purity stabilizer 1.
The external force acting from the stabilizing material lid 6 side is transmitted to the high purity aluminum stabilizing material 3 at a portion of the stabilizing material lid 6 corresponding to the storage position of the high purity aluminum stabilizing material 3. A superconducting conductor characterized in that a space portion 88 extending in the longitudinal direction of the superconducting conductor is provided so as to reduce the occurrence of heat. 7. The stabilizer according to claim 1, wherein the high-purity copper stabilizing material 1 is provided on the opening side of the storage groove 1a so as to be lower than the tips of the side legs 1c and 1d. The lid 6 is disposed, and a groove 84 extending in the longitudinal direction of the superconducting conductor is provided at the opening end of the storage groove 1a to reduce transmission of external force acting from the opening side to the high precision aluminum stabilizing material 3. Characteristic superconducting conductor.