WO2023170773A1

WO2023170773A1 - Positioning member, and superconducting magnet and superconducting magnet manufacturing method

Info

Publication number: WO2023170773A1
Application number: PCT/JP2022/009896
Authority: WO
Inventors: 英明三浦; 泰佑服部
Original assignee: 三菱電機株式会社
Priority date: 2022-03-08
Filing date: 2022-03-08
Publication date: 2023-09-14
Also published as: JP7142811B1; JPWO2023170773A1

Abstract

In order to adjust the positions of pancake coils (2) which are placed on a stage (9) and in which superconducting wires constituting superconducting magnets (1) are wound, positioning members (3) are provided inside the pancake coils (2) and comprise pressing mechanisms (31) that are brought into surface contact with the inner circumferential surfaces of the pancake coils and that press the surfaces in a radial direction. The positions of the pancake coils (2) are adjusted by means of the pressing mechanisms (31) such that the center axes (5) of the pancake coils (2) are aligned with a preset position (4) of the stage (9). This makes it possible to, even when the inner diameters of the pancake coils (2) are different from each other, suppress displacement of the pancake coils (2) that are being energized, and to suppress degradation of superconducting characteristics of superconducting wires.

Description

Positioning member, superconducting magnet, and method for manufacturing superconducting magnet

The present application relates to a positioning member used for positioning a pancake coil wound with a superconducting wire in a superconducting magnet device, a superconducting magnet using this positioning member, and a method for manufacturing a superconducting magnet.

In recent years, progress has been made in the development of superconducting wires in which a superconductor is embedded in a metal sheath or a superconducting thin film is formed on a substrate. Among these, an oxide-based superconducting wire provided with a superconducting layer made of an oxide superconductor, which is a high-temperature superconductor whose transition temperature is higher than the liquid nitrogen temperature, is attracting attention. Even in superconducting magnets that require a high-strength magnetic field, such as central solenoid coils for tokamak-type fusion reactors, magnetic fields are generated using superconducting coils formed by winding oxide-based superconducting wires. A technique has been proposed.

Due to the structural characteristics of the oxide-based superconducting wire, the above-mentioned superconducting magnet has problems such as being susceptible to peeling stress, deteriorating the superconducting properties, and not being able to generate the desired magnetic field (for example, see Non-Patent Document 1) . In order to solve this problem, a superconducting device is known in which a plurality of pancake coils forming a superconducting magnet are fixed from the inner peripheral surface of the coil (for example, see Patent Document 1).

JP2019-207917A

However, in the superconducting coil body of Patent Document 1, if the inner diameter of each pancake coil differs due to manufacturing error or other reasons, the positioning member does not contact the inner peripheral surface of the coil, and during excitation, The coil may be displaced. This displacement causes mechanical stress to act on the connection between the pancake coils, which may result in deterioration of the superconducting properties of the superconducting wire near the connection.

The present application has been made to solve the above-mentioned problems, and even if the inner diameter dimensions of the pancake coils composing a superconducting magnet are different, the displacement of the coils during excitation can be suppressed, and the characteristics of the superconducting wire can be improved. The object of the present invention is to obtain a pancake coil positioning member that can prevent deterioration.

The positioning member disclosed in the present application is provided inside the pancake coil in order to adjust the position of the pancake coil around which the superconducting wire constituting the superconducting magnet placed on the stage is wound. A positioning member disposed on the stage, the positioning member being brought into surface contact with the inner circumferential surface of the pancake coil and having a pressing mechanism for pressing the pancake coil in the radial direction; The present invention is characterized in that the position of the pancake coil is adjusted so that the central axis of the pancake coil is aligned with a predetermined position on the stage.

Further, the superconducting magnet disclosed in the present application is characterized in that a plurality of the pancake coils are stacked and manufactured using the positioning member.

Furthermore, the method for manufacturing a superconducting magnet disclosed in the present application includes a step of placing a pancake coil wound with a superconducting wire constituting the superconducting magnet on a stage, and using a distance meter provided on the stage to a step of measuring the distance between a predetermined position and the central axis of the pancake coil; and a step of bringing a plurality of positioning members provided on the stage and having a pressing mechanism into surface contact with the inner peripheral surface of the pancake coil. and radially pressing the pancake coil from the inner peripheral surface side by the pressing mechanism to align the central axis of the pancake coil to a predetermined position of the stage based on the distance. and a step of adjusting the position of the pancake coil.

According to the positioning member of the present application, when manufacturing a superconducting magnet, by independently adjusting the pressure applied to the inner peripheral surface side of each pancake coil that constitutes the superconducting magnet, it is possible to adjust the inner diameter of each pancake coil. Even when the dimensions are different, the displacement of the pancake coil during excitation can be suppressed, and the deterioration of the superconducting properties of the superconducting wire of the superconducting magnet device can be prevented.

1 is a schematic cross-sectional view showing the entire superconducting magnet device using the positioning member according to Embodiment 1. FIG. FIG. 2 is a schematic perspective view showing a superconducting magnet portion in FIG. 1. FIG. FIG. 2 is a schematic plan view showing the pancake coil and positioning member along line A-A' in FIG. 1. FIG. FIG. 4 is a cross-sectional view showing the superconducting magnet and the positioning member taken along line B-B' in FIG. 3; FIG. 7 is a schematic plan view showing the relationship between the pancake coil and the position of a distance meter according to Embodiment 2. FIG. 7 is a diagram showing a flowchart of a method for manufacturing a superconducting magnet in Embodiment 3. FIG.

Embodiment 1.
FIG. 1 is a schematic cross-sectional view showing the entire superconducting magnet device using the positioning member according to the first embodiment, and FIG. 2 is a schematic perspective view showing the superconducting magnet portion shown in FIG. 3 is a schematic plan view showing the pancake coil and the positioning member along the line AA' in FIG. 1, and FIG. 4 is a schematic plan view showing the superconducting magnet and the positioning member along the line BB' in FIG. It is a sectional view showing an extension member.

First, the overall configuration of a superconducting magnet device 10 according to Embodiment 1 will be described using FIG. 1. The superconducting magnet device 10 includes a pancake coil 2 , a superconducting magnet 1 made up of a plurality of stacked pancake coils 2 , a stage 9 on which the superconducting magnet 1 is placed, and a stage 9 arranged on the stage 9 and containing the pancake coils 2 . A positioning member 3 that performs positioning, a refrigerator 6 that cools the superconducting magnet 1, a radiation shield tank 7 that shields the thermal radiation of the superconducting magnet 1, and a cryostat 8 that houses the superconducting magnet 1 and maintains a low temperature. , is equipped with.

A refrigerator 6 is attached to the lower part of the cryostat 8, and the refrigerator 6 includes a first cooling section 61 and a second cooling section 62. Generally, the first cooling section 61 is , several tens of K, and the second cooling section 62 is cooled to a temperature of several K. The first cooling unit 61 is thermally connected to the radiation shield tank 7 . Further, the second cooling unit 62 is thermally connected to the stage 9, and cools the superconducting magnet 1 via it. The stage 9 on which the superconducting magnet 1 is placed is preferably made of a good thermal conductor such as oxygen-free copper or high-purity aluminum. Although not shown in FIG. 1, in reality, in addition to these, lead wires for supplying current and measurement wires for sensors that measure voltage and temperature are installed. Note that the inside of the cryostat 8 is maintained in a vacuum state in order to reduce the intrusion of heat from the outside air.

2 is a schematic perspective view showing the superconducting magnet 1 and the positioning member 3, and FIG. 3 is a schematic plan view showing the pancake coil 2 and the positioning member 3 along line AA' in FIG. be. As shown in FIGS. 2 and 3, a plurality of positioning members 3 are arranged along the inner peripheral surface of the pancake coil 2 around which the superconducting wire is wound. The pancake coil 2 is adjusted and fixed so that its central axis 5 is located at a predetermined position 4 on the stage 9.

FIG. 3 shows the state before the position of the central axis 5 of the pancake coil 2 is adjusted to a predetermined position 4 on the stage 9. 2 and 3, the case is shown in which the number of positioning members 3 is three, and by adjusting the pressure applied to the pancake coil 2 by each positioning member 3, the pancake The position of the coil 2 is uniquely determined and fixed. Note that although the above figure shows a case where the number of positioning members 3 is three, it may be any other number. Further, although FIGS. 2 and 3 of this embodiment show an example in which the stage 9 has a disk shape, it may have another shape.

FIG. 4 is a cross-sectional view taken along line B-B' in FIG. 3. The first pancake coil 21 and the second pancake coil 22 constitute a coil unit, and the superconducting magnet 1 is constituted by stacking the coil units in multiple stages. Insulating paper 23 is inserted between the coil units for electrical insulation. The first pancake coil 21 is pressed radially from the inner peripheral surface side by the first pressing member 31 and the holding member 33, and the central axis 51 of the first pancake coil 21 is set in advance on the stage 9. The stage 9 is then fixed to the stage 9. Similarly, the second pancake coil 22 is pressed radially from the inner peripheral surface side by the second pressing member 32 and the holding member 33, so that the central axis 52 of the second pancake coil 22 is placed on the stage. The stage 9 is adjusted to a predetermined position 4 and fixed to the stage 9.

Note that in FIG. 4, the first pressing member 31 includes a first contact member 311 and a first pressing member 312, and the second pressing member 32 includes a second contact member 321 and a second pressing member 312. and a pressing member 322. As shown in FIG. 3, the first contact member 311 maintains good contact with the inner circumferential surface of the first pancake coil 21, and similarly, the second contact member 321 In order to maintain good contact with the inner circumferential surface of the second pancake coil 22, it is preferable that the cross section of the surface of each positioning member 3 that comes into contact with the pancake coil 2 is semi-cylindrical. However, any structure may be used as long as it is a mechanism that can press the first pancake coil 21 and the second pancake coil 22 in the radial direction from the inner peripheral surfaces thereof.

Furthermore, at the connecting portion between the first pressing member 312 and the holding member 33, for example, as shown in FIG. In addition, the holding member 33 has a hole (female thread) in which a spiral groove is formed, and the spiral groove of the first pressing member 312 and the spiral groove of the holding member 33 are in a screw-fitting relationship with each other. It has a structure with The first pancake coil 21 is positioned by rotating the first pressing member 312 to press the first pancake coil 21 via the first contact member 311. This is done by adjusting the center axis 51 to be at a predetermined position 4 on the stage 9. By performing the above-mentioned operations on each of the three positioning members 3, the first pancake coil 21 is finally positioned and fixed. The same applies to the connection between the second pressing member 322 and the holding member 33.

Note that the first pressing member 312 and the second pressing member 322 have a tail portion on the opposite side from the first contact member 311 and the first contact member 321 for rotating in accordance with the shape of the tip of the driver. A slotted groove, a Phillips groove, or a hexagonal hole for a hexagonal wrench are provided as required. Alternatively, the positioning member 3 may perform only positioning adjustment, and fixation may be performed using another member.

The thermal contraction rate of the positioning member 3 is preferably smaller than the thermal contraction rate of the first pancake coil 21 and the second pancake coil 22 during cooling. Further, the first pancake coil 21 and the second pancake coil 22 are electrically connected by a superconducting wire or a copper wire. The material constituting the positioning member 3 may be any non-magnetic material, and any material may be used as long as it satisfies the above conditions.

According to the above structure, even if there is an error in the inner diameter dimension of each pancake coil during manufacturing of the superconducting magnet, the inner surface side portion of each pancake coil and the contact member of the positioning member are in close contact with each other, so that, for example, Even in an environment where electromagnetic force during excitation or thermal stress during cooling is applied, displacement of each of the first pancake coil and the second pancake coil can be suppressed. Thereby, it is possible to suppress mechanical stress from being applied to the connection portion where the first pancake coil and the second pancake coil are electrically connected. As a result, it is possible to suppress the mechanical stress applied to the superconducting wire forming the connection part and the first pancake coil or the second pancake coil near the connection part, and as a result, the deterioration of superconducting properties is reduced. can be realized.

Furthermore, in a superconducting magnet, in order to reduce errors with the designed magnetic field, it is necessary to align a predetermined position of the stage with the center axis of each pancake coil. The positioning member includes a mechanism for pressing the pancake coil in the radial direction from the inner peripheral surface of the coil, and is capable of adjusting the position in the horizontal direction of the plane of the drawing in FIG. This mechanism allows the predetermined position of the stage to coincide with the center axis of each pancake coil.
Therefore, according to this structure, it is possible to provide a superconducting magnet in which the superconducting properties do not deteriorate and the difference between the designed magnetic field and the actually formed magnetic field is small.

As described above, according to the superconducting magnet manufactured using the positioning member according to the first embodiment, the positioning member of the pancake coil allows the inside of each of the pancake coils constituting the superconducting magnet to be adjusted. By independently adjusting the pressing force applied to the circumferential surface, the displacement of the pancake coils during excitation can be suppressed even if the inner diameter dimensions of the individual pancake coils are different, and the superconductivity of the superconducting wire can be suppressed. This has the remarkable effect of making it possible to suppress deterioration of characteristics.

Embodiment 2.
FIG. 5 is a schematic plan view showing the relationship between the pancake coil and the distance meter that constitute the superconducting magnet according to the second embodiment. Components other than the distance meter 11 are the same as those in FIG. 3 of Embodiment 1, so description thereof will be omitted. Note that in FIG. 5, the positioning member 3 is omitted.

As described in the first embodiment, in order to reduce the error with the designed magnetic field in the superconducting magnet 1, it is necessary to align the predetermined position 4 of the stage 9 with the central axis 5 of the pancake coil 2. It is necessary to fix the pancake coil 2 at an accurate position.

In the second embodiment, in order to measure the position of the central axis 5 of the pancake coil 2 with respect to the predetermined position 4 of the stage 9 on which the superconducting magnet 1 is placed, The distance is measured using a distance meter 11 installed at The distance meter 11 measures the distance between a predetermined position 4 of the stage 9 and the inner peripheral surface of the pancake coil 2, and specifies the position of the central axis 5 of the pancake coil 2. Here, in order to uniquely and accurately specify the position of the central axis 5 of the pancake coil 2, it is desirable to use three or more measurement points.

Next, based on the distance between the predetermined position 4 of the stage 9 and the measured inner diameter of the pancake coil 2, the central axis 5 of the pancake coil 2 is aligned with the predetermined position of the stage 9. , the position of the pancake coil 2 is adjusted and fixed by a positioning member 3 provided on the stage 9.

In order to accurately specify the position of the central axis 5 of the pancake coil 2 with respect to the predetermined position 4 of the stage 9 using the distance meter 11, non-contact measurement using a laser displacement meter is desirable, for example. Alternatively, a method may be adopted in which the distance from the predetermined position 4 of the stage 9 to the inner circumferential surface of the pancake coil 2 is directly measured with a ruler. Further, in the above explanation, the case where the distance meter 11 is installed on the predetermined position 4 of the stage 9 has been explained, but even when it is installed at a place other than the predetermined position 4 on the stage 9, it can be set in advance. If the relationship between the position of the installed distance meter 11 and the predetermined position 4 of the stage 9 is known, it is possible to measure the distance by correcting it.

As described above, according to the superconducting magnet manufactured using the positioning member according to the second embodiment, the position of the center axis of the pancake coil is accurately calculated using the distance meter, and the positioning member is used to accurately calculate the position of the center axis of the pancake coil. By fixing the pancake coil in an accurate position according to the predetermined position of the magnetic field, it is possible to reduce the error with the designed magnetic field, and it is possible to suppress the deterioration of the superconducting properties of the superconducting wire. This has a remarkable effect.

Embodiment 3.
FIG. 6 is a diagram showing a flowchart for explaining a method for manufacturing a superconducting magnet according to Embodiment 3. The superconducting magnet device 10 and its configuration are the same as those in Embodiment 1, so a description thereof will be omitted.

A method for manufacturing the superconducting magnet 1 will be described using a flowchart with reference to FIGS. 1 to 5. Here, a case will be described in which the pancake coil 2 is composed of a unit of a first pancake coil 21 and a second pancake coil 22.

First, in step S01, the first pancake coil 21 is placed on the stage 9.

Next, in the process of step S02, the distance between the central axis 5 of the pancake coil 21 obtained from the inner peripheral surface of the first pancake coil 21 and the predetermined position 4 of the stage 9 is determined in advance on the stage 9. Measurement is performed using a laser displacement meter placed at the specified position.

Subsequently, in step S03, the central axis 5 of the first pancake coil 21 is aligned with the predetermined position 4 of the stage 9.

Furthermore, in step S04, the positioning member 3 is used to align the center axis of the first pancake coil 21 with the predetermined position 4 of the stage, and then move the first pancake coil 21 inside. The position of the first pancake coil 21 is adjusted and fixed by pressing in the radial direction from the circumferential surface side.

In the process of step S04, the second pancake coil 22 is placed on the stage 9, similar to the process of step S01 for the first pancake coil 21. Here, in order to electrically insulate the first pancake coil 21 and the second pancake coil 22, an insulating paper 23 is inserted between the first pancake coil 21 and the second pancake coil 22. You may. Further, in order to improve heat transfer between the first pancake coil 21 and the second pancake coil 22, there is no heat transfer between the first pancake coil 21 and the second pancake coil 22. It is desirable to insert a good thermal conductor such as oxygenated copper or high-purity aluminum, grease, or resin.

Subsequently, in step S05, the second pancake coil 22 is stacked and placed on the first pancake coil 21.

Next, in step S06, the distance between the central axis 5 of the pancake coil 21 obtained from the inner peripheral surface of the first pancake coil 21 and the predetermined position 4 of the stage 9 is determined in advance on the stage 9. Measurement is performed using a laser displacement meter placed at the specified position.

Subsequently, in step S07, the central axis 5 of the first pancake coil 21 is aligned with the predetermined position 4 of the stage 9.

Furthermore, in the process of step S08, the second pancake coil 22 is moved using the positioning member 3 with the center axis 52 of the second pancake coil 22 aligned with the predetermined position 4 of the stage. The position of the second pancake coil 22 is adjusted and fixed by pressing in the radial direction from the inner peripheral surface side.

Further, after the positions of the first pancake coil and the second pancake coil are adjusted independently and sequentially, the first pancake coil 21 and the second pancake coil 22 in FIG. It is desirable to provide a connection part for making a connection.

Here, it is assumed that the pancake coil 21 is installed on the stage 9, but the presence or absence of the stage 9 is not necessarily concerned. Further, as described in the second embodiment, the case where a laser displacement meter is used for distance measurement has been described, but other methods may be used. In addition, while the positioning member 3 is used to adjust the position of the first pancake coil 21, it is also fixed. However, as described in the second embodiment, the final position of the first pancake coil 21 is The fixation may be performed by another member or means. The same applies to the second pancake coil 22.

As described above, according to the method for manufacturing a superconducting magnet according to the third embodiment, since each pancake coil is in contact with the positioning member and fixed, the displacement of the pancake coil during excitation and cooling It is possible to suppress the deterioration of the superconducting properties of the superconducting wire, and it is also possible to match the center axis of each pancake coil, so the difference between the actual magnetic field and the design magnetic field is small. It has the remarkable effect of being able to provide magnets.

Note that the superconducting magnet device manufactured using the positioning member according to the embodiment described above has been described using a plurality of embodiments as examples. Furthermore, in the above embodiments, the superconducting wire constituting the superconducting magnet is explained using an oxide-based superconducting wire having a high aspect ratio as an example, but the superconducting wire is not limited to the oxide-based superconducting wire. do not have.

Additionally, while this application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments may be specific to the specific embodiments. The present invention is not limited to application, but can be applied to the embodiments alone or in various combinations.
Accordingly, countless variations not illustrated are envisioned within the scope of the technology disclosed herein. For example, this includes cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with components of other embodiments.

1 superconducting magnet, 2 pancake coil, 21 first pancake coil, 22 second pancake coil, 3 positioning member, 31 first pressing member, 32 second pressing member, 33 holding member, 311th 1 contact member, 312 first pressing member, 321 second contact member, 322 second pressing member, 4 predetermined stage position, 5 central axis of pancake coil, 51 first pancake coil , 52 Central axis of the second pancake coil, 6 Refrigerator, 7 Radiation shield tank, 8 Cryostat, 9 Stage, 10 Superconducting magnet device, 11 Distance meter, 23 Insulating paper, 61 First cooling section, 62 Second cooling section.

Claims

a positioning member provided inside the pancake coil and placed on the stage in order to adjust the position of the pancake coil around which the superconducting wire constituting the superconducting magnet placed on the stage is wound; And,
a pressing mechanism that is brought into surface contact with the inner circumferential surface of the pancake coil and presses the pancake coil in a radial direction;
A positioning member characterized in that the pressing mechanism adjusts the position of the pancake coil so that the central axis of the pancake coil is aligned with a predetermined position on the stage.
The pressing mechanism is
a contact member that makes surface contact with the inner peripheral surface side of the pancake coil;
a pressing member attached to the contact member and pressing the pancake coil;
The positioning member according to claim 1, further comprising a holding member disposed on the stage that supports the pressing member.
The pressing member has a rod-like shape, and a spiral groove is formed on the side surface, and a hole having a spiral groove is formed in the holding member, and the spiral groove of the pressing member and the spiral groove of the holding member are connected to each other. are in a screw-fit relationship with each other,
3. The positioning member according to claim 2, wherein the pancake coil is pressed via the contact member by rotating the pressing member.
The pancake coil is constituted by a unit of a first pancake coil and a second pancake coil, and the positions of the first pancake coil and the second pancake coil are adjusted independently. The positioning member according to any one of claims 1 to 3, characterized in that:
The positioning member according to any one of claims 1 to 4, wherein the positioning member has a thermal contraction rate smaller than that of the pancake coil.
A superconducting magnet manufactured by stacking a plurality of the pancake coils using the positioning member according to any one of claims 1 to 5.
A distance meter is placed on the stage inside the pancake coil, and the distance meter is used to measure the distance between a predetermined position of the stage and the central axis of the pancake coil. The superconducting magnet according to claim 6, characterized in that:
A process of placing a pancake coil wound with superconducting wire forming a superconducting magnet on a stage;
measuring the distance between a predetermined position of the stage and the central axis of the pancake coil using a distance meter provided on the stage;
bringing a plurality of positioning members each having a pressing mechanism provided on the stage into surface contact with the inner peripheral surface side of the pancake coil;
The pancake is pressed radially from the inner peripheral surface side of the pancake coil by the pressing mechanism to align the central axis of the pancake coil with a predetermined position on the stage based on the distance. a step of adjusting the position of the coil;
A method for manufacturing a superconducting magnet, characterized by comprising:
The pressing mechanism is
a contact member that makes surface contact with the inner peripheral surface side of the pancake coil;
a pressing member attached to the contact member and pressing the pancake coil;
9. The method of manufacturing a superconducting magnet according to claim 8, further comprising: a holding member disposed on the stage that supports the pressing member.
The pressing member has a rod-like shape, and a spiral groove is formed on the side surface, and a hole having a spiral groove is formed in the holding member, and the spiral groove of the pressing member and the spiral groove of the holding member are connected to each other. are in a screw-fit relationship with each other,
10. The method for manufacturing a superconducting magnet according to claim 9, wherein the pancake coil is pressed via the contact member by rotating the pressing member.
The pancake coil is constituted by a unit of a first pancake coil and a second pancake coil, and the positions of the first pancake coil and the second pancake coil are independently and sequentially adjusted. 9. The method for manufacturing a superconducting magnet according to claim 8.