JPH0855715A - Superconducting coil manufacturing method - Google Patents

Abstract

PURPOSE:To obtain a manufacturing method by which a superconducting coil which can prevent the occurrence of a quenching phenomenon so that the cooling effect of the coil can be improved while the coil is energized. CONSTITUTION:After an organic synthetic film tape 1 is wound around a flat stranded cable by 1/2 wrap, an epoxy resin 4 is continuously applied to one external surface of the cable 2 in a granular state. The insulated conductor thus prepared is formed by pressurizing-heating cure after the conductor is wound around a coil bobbin and incorporated in the iron core of an electromagnet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting coil,
In particular, it relates to a method for manufacturing a superconducting coil with improved wire insulation.

[0002]

2. Description of the Related Art In a conventional method for manufacturing a superconducting coil, a glass base tape is impregnated with a thermosetting resin to form a prepreg tape in a B-stage state, or both sides of an organic synthetic film are used as wire insulation. An insulating tape that has been treated with the same prepreg is wound around the superconducting conductor.

The superconducting conductor thus insulated from the wires is wound in a coil shape in a winding form and then heated in a pressurized state. As a result, the wire of the coil and the insulating tape are adhered to each other and molded integrally to prevent deformation due to transport until assembly, and also facilitate insertion of the superconducting magnet into the iron core, which is caused by electromagnetic force during energization. Quenching is prevented by preventing significant movement.

However, the superconducting coil manufactured by such a manufacturing method has the following drawbacks.

That is, when this superconducting coil is incorporated into an iron core of an electromagnet and cooled until the superconducting conductor reaches a critical temperature at which the superconducting conductor is in a superconducting state, the superconducting coil becomes a supporting member of the superconducting coil or a non-magnetic steel. Due to the difference in the coefficient of thermal expansion from that of the collar or the like, the superconducting coil and these supporting members may be displaced from each other and a slight gap may be formed.

Then, when the superconducting coil is energized,
The superconducting coil may move inside the superconducting magnet due to the electromagnetic force acting between the iron core and the iron core, which may cause an unstable state in the superconducting state.

On the other hand, a method may be considered in which pre-stress is applied to the superconducting coil in advance so that the superconducting coil is pressed down to a pressure that does not create a gap even in the superconducting state. In this method, a crack occurs in the adhesive layer between the superconducting wire and the tape. However, this may cause a quench that breaks the superconducting state of the superconducting coil when energized.

Further, the method of directly and completely solidifying the outer circumference of the superconducting wire with a thermosetting resin or a thermoplastic resin not only greatly reduces the thermal conductivity of the superconducting wire and the refrigerant, but also fixes the superconducting wire rigidly. Since the superconducting wire itself is locally prevented from following the electromagnetic force applied to the superconducting wire within a range in which the superconducting wire itself does not quench, the possibility of quenching increases.

Further, while the superconducting coil is repeatedly subjected to electromagnetic force, the cured resin between the outer periphery of the superconducting wire and between layers becomes fatigued and cracks occur, which not only cause quenching but also cause long-term quenching. When the electromagnetic force is repeatedly applied to the superconducting coil in this state by the operation over the entire range, there is a possibility that the entire cured resin may be damaged and the coil may be damaged.

On the other hand, in order to improve such a defect,
In Japanese Patent Publication No. 2-35442, an organic synthetic film coated with a synthetic resin adhesive on one side is wound around the outer circumference of a superconducting wire with the coated surface of the synthetic resin adhesive being the outside, and this strand insulated conductor is coiled. A method for manufacturing a superconducting coil has been proposed, in which the superconducting coil is molded by pressurizing and heating with a press to produce a superconducting coil, which is incorporated into a magnet structure such as an iron core or a stainless collar while applying pressure.

According to this manufacturing method, since the bonding surface between the superconducting wire and the insulating tape is reduced, some improvement effect can be expected.

[0012]

However, in such a method of manufacturing a superconducting coil, since the organic synthetic tape coated with the synthetic resin adhesive is used as the insulation of the wire, the wire insulated conductor is wound in the coil form. During molding, bending and twisting of the superconducting wire applied to the insulated wire conductor causes the organic synthetic tapes wound around the superconducting wire to be displaced from each other, resulting in a gap between the organic synthetic tapes. There is a risk.

If the organic synthetic tape is displaced,
In order to prevent the generation of gaps between the organic synthetic tapes, the organic synthetic tapes must be wound so that the entire surfaces thereof overlap each other. Then, not only the winding takes time, but the heat conduction may be hindered due to the overlapping of the organic synthetic tapes.

Further, even in the case of a wire insulated conductor obtained by wrapping an organic synthetic tape coated with a synthetic resin adhesive only on the outside so that almost all the surfaces are overlapped with each other, the synthetic resin softened during pressurization and heating cure by the above-mentioned press. The adhesive may enter between the superposed organic synthetic tapes and adhere to the superconducting wires inside.

Then, the above-mentioned cracks are generated,
Fixing to a rigid may cause a quench to occur. Further, according to the method of manufacturing the superconducting coil, the lap-wound organic synthetic tapes are adhered to each other due to the invading synthetic resin adhesive.

As a result, the refrigerant is prevented from entering the inside of the organic synthetic tape, the refrigerant does not come into direct contact with the superconducting wire, and the softened resin increases the fluidity to at least the entire outer circumference of the superconducting wire. Since the resin layer is formed, the heat transfer of the refrigerant is performed through the resin layer, which reduces the cooling efficiency of the superconducting coil.

Therefore, an object of the present invention is to solve the above problems, and in the critical state,
It is an object of the present invention to provide a method for manufacturing a superconducting coil that can eliminate the risk of an unstable state.

[0018]

According to a first aspect of the present invention, there is provided a method for manufacturing a superconducting coil, wherein an adhesive is applied to at least a part of one side of an insulated conductor having a film tape wound around the outer periphery by lap winding. It is characterized in that it is wound by a winding die and heated under pressure to be molded.

According to a second aspect of the present invention, there is provided a method for manufacturing a superconducting coil, wherein an insulated conductor is wound in a roll form, except for an adhesive-applied portion of a film tape having an adhesive applied on one side. It is characterized by being rotated, pressurized and heated to be molded.

Further, the method of manufacturing a superconducting coil according to the third aspect of the present invention is characterized in that the superconducting coil heated under pressure is incorporated into the iron core by applying a pre-pressure.

[0021]

In the superconducting coil obtained according to the present invention, the conductors are fixed to each other only between the outermost tapes wound in layers,
There is no resin flow-in between the wrapping organic synthetic film tape used for wire insulation and the conductor, and it is possible to maintain the shape required for the handling process during assembly. Allows smooth movement of the conductor during excitation without quenching.

Further, a gap having the thickness of the tape wound in layers is formed between the layers of the coil to allow the inflow of the refrigerant, and further, the heat transferable area between the superconducting wire and the refrigerant is increased, so that the cooling effect is obtained. Can be significantly improved.

The tape which is wrapped directly on the outside of the superconducting wire and insulated from the strand does not have the adhered portion of the wrapped wire, and the refrigerant can flow into the superconducting wire side slightly, but the refrigerant and the superconducting wire are directly connected to each other. Cooling can be expected by contact, and the stability of the superconducting state is improved.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for manufacturing a superconducting coil of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a process of manufacturing an insulated conductor used in the superconducting coil according to the first aspect of the invention.

As shown in FIG. 1, the thickness is 25.4 μm and the width is 16 mm.
The polyimide organic synthetic film tape 1 is wrapped around the outer periphery of the rectangular shaped twisted wire 2 by half the width of the tape to form a wire insulation by the tape.

Next, as shown in FIG. 2 (a), epoxy resin 5 is granularly applied to the central portion of the surface of one surface of the tape-insulated conductor in a width half the width of the tape-insulated conductor. B
Semi-cure into a stage. 2 (b) shows another embodiment described in detail later, and FIG. 3 shows a polyimide organic synthetic film tape used in the invention described in claim 2 described later.

FIG. 4 shows the insulated conductor 4 thus formed.
FIG. 6 is a partial vertical sectional view showing a state of being heated and cured by a heat press, showing a case of a superconducting coil incorporated in a superconducting dipole magnet for a beam accelerator described later in FIG.

In FIG. 4, the superconducting coil 6 is wound around the outer periphery of a medium-sized mold 8 with a heater incorporated in a heat press in advance. The middle die 8 around which the superconducting coil 6 is wound is inserted into the outer die 9 of the heat press, and the lower end of the pressure plate 10a is inserted between the middle die 9 and the outer die 9 from above.

Next, when high-pressure hydraulic oil is supplied to the hydraulic cylinder 20 from a hydraulic source (not shown), the guide columns 22 erected at the four corners of the base 21 on which the hydraulic cylinder 20 is placed serve as guide shafts. The middle base 18 rises, pressurizes the superconducting coil 6 from above and below with the upper base 19, and energizes the heater 7 to heat and cure the superconducting coil 6.

Here, when the dimension of the stack of the superconducting coils 6 when compressed by the heat press is H, this dimension H has different values depending on the size taken out from the heat press. Therefore, before assembling the superconducting coil into the magnet structure, if the elastic modulus of each actual product after pressure heating and curing is obtained in advance, the magnet structure generated when the entire magnet is cooled to a temperature at which it becomes a superconducting state. It is possible to determine the amount of displacement of the coil capable of absorbing the difference in the amount of contraction between the coil and the coil and capable of sufficiently holding the superconducting coil, and the pressing force for obtaining the amount of displacement.

FIG. 5 is a vertical cross-sectional view showing a process of incorporating the superconducting coil, which has been heated and cured under the above-mentioned dimensions in FIG. 4, into the structure of the beam accelerating superconducting dipole magnet. In FIG. 5, the lower yoke 12 and the side yoke 14
Is firmly fixed with a tightening bolt 15, and a vacuum chamber 13 is housed in the center of a side yoke 14.

After a spacer 16 is placed on at least one of the superconducting coil 6 and the lower yoke 12 or between the superconducting coil 6 and the upper yoke 11 to secure a necessary displacement amount t of the superconducting coil 6, The superconducting magnet is assembled by pressurizing the yoke 11 with the bolts 15 and tightening until the lower surface of the upper portion 11 and the joint surface of the upper end of the side view yoke 14 come into complete contact.

The superconducting coil manufactured by the method for manufacturing a superconducting coil according to the present invention has a compressive residual stress applied between the strands of the superconducting coil even if the superconducting coil is cooled to the superconducting temperature. Even if an electromagnetic force is applied by the excitation, the movement inside the structure is restricted, and the quench phenomenon can be prevented.

Further, since each element wire is adhered through the polyimide organic synthetic film tape by heat curing,
The epoxy resin used to maintain the shape of the superconducting coil can maintain the coil shape and is easy to handle during transportation. Within the range where the quench phenomenon does not occur against the electromagnetic force applied to the superconducting wire during the excitation of the superconducting coil, because the element wires and the polyimide organic synthetic film do not adhere to the inside of the tape and are not adhered with the epoxy resin. It also enables a slight displacement of.

In addition, since the path through which the refrigerant flows is formed between the polyimide organic synthetic tape and the strands, the cooling effect is remarkably improved, and it is possible to cope with minute heat generation which has conventionally been a cause of quenching. Therefore, it is possible to surely prevent the occurrence of the instability factor as compared with the conventional superconducting coil.

Next, FIG. 3 is a diagram showing an example of a polyimide organic synthetic film tape used in the method for producing a superconducting coil according to the second aspect of the invention.

Similar to FIG. 2, in FIG. 3, a polyimide organic synthetic film tape 1 having a thickness of 25.4 μm and a width of 16 mm is wound around the outer periphery of the flat-shaped molded stranded wire 2 by a half wrap. The synthetic tape 1 is provided on one side of one side with a width of one-third of the width W of the polyimide organic synthetic film tape 1 and the epoxy resin 5 applied to the wire insulated conductor shown in FIG. Apply continuously.

The polyimide organic synthetic tape 1 coated with the epoxy resin 5 is halved on the outer periphery of the rectangular shaped twisted wire 2.
When wrapping with a wrap, the epoxy resin 5 is applied to the outside so that the entire application surface is sufficiently exposed.

Also in the case of the wire insulated conductor for a superconducting coil wound with such a polyimide organic synthetic film tape, it is wound around the middle mold 8 of the heat press shown in FIG. By applying pressure with 10a, a part of each layer of the superconducting coil is bonded to the polyimide organic synthetic tape 1 and the epoxy resin 5.

At this time, since the epoxy resin does not penetrate between the outer surfaces of the rectangular shaped twisted body 2 on the inner surface side of the polyimide organic synthetic tape 1 of each layer, molding is performed with the wire insulated conductor shown in FIGS. 1 and 2. Similar to the superconducting coil 6 described above, the cooling effect by the refrigerant can be enhanced.

Further, in the strand insulated conductors shown in FIGS. 2A and 3, the polyimide organic synthetic tape 1 constituting the strand insulation is coated with the granular epoxy resin 5 in a strip shape. However, for example, the epoxy resin 5 may be applied in a strip shape at the central portion as shown in FIG. 2A with a width of 1/5 to 1/6 of the width of the wire insulated conductor. In addition, the width of the strip-shaped coating layer is further narrowed to reduce the strip-shaped coating layer to 2
It may be a line.

Further, the epoxy resin coating shape shown in FIGS. 1, 2A and 3 is neither granular nor strip-shaped,
For example, as shown in FIG. 2 (b), it may be applied intermittently as a disc-shaped 6 having a diameter of 1/4 to 1/5 of the width of the wire insulated conductor.

2 (a) and 2 (b), the epoxy resin 5 is applied to one side, but it may be applied to both sides by further narrowing the width of the applied surface.

[0044]

As described above, according to the method of manufacturing a superconducting coil of the present invention as set forth in claim 1, an adhesive is applied to at least a part of one side of an insulated conductor having an outer periphery wound with a film tape by lap winding, Since the adhesive is prevented from entering between the film tapes and between the film tapes and the superconducting conductor by winding with a winding mold and pressurizing and heating, the cooling effect of the superconducting coil is improved by allowing the inflow of refrigerant. Therefore, it is possible to obtain a method for manufacturing a superconducting coil that can increase the stability of the superconducting coil when energized at a critical temperature.

Further, according to the method for manufacturing a superconducting coil of the invention as defined in claim 2, an insulating conductor wound in a layered manner excluding an adhesive application portion of a film tape having an adhesive applied on one side of one side is wound. By winding and rolling under pressure to prevent the adhesive from entering between the film tapes and between this film tape and the superconducting conductor, it made it possible for refrigerant to enter and enhance the cooling effect of the superconducting coil. It is possible to obtain a method for manufacturing a superconducting coil that can increase the stability of the superconducting coil when energized at a temperature.

Further, according to the method of manufacturing a superconducting coil of the invention as set forth in claim 3, by prepressing the superconducting coil heated under pressure and incorporating it into the iron core, the space between the film tapes and between the film tape and the superconducting coil is increased. It prevents the adhesive from entering between the conductors and allows the refrigerant to enter, and the movement of the coil against electromagnetic force due to energization is reduced by the pre-pressure, so the stability of the superconducting coil when energized at the critical temperature is improved. It is possible to obtain a method for manufacturing a superconducting coil that can be manufactured.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an insulated conductor used in an embodiment of a method for manufacturing a superconducting coil according to the invention described in claims 1 and 3.

FIG. 2 is a perspective view showing an example of an insulated conductor used in the method for manufacturing a superconducting coil according to the first and second aspects of the invention.

FIG. 3 is a view showing a film tape wound around an insulated conductor used in the method for manufacturing a superconducting coil according to the second aspect of the present invention.

FIG. 4 is a front view of a heat press used in the method for manufacturing a superconducting coil of the present invention.

FIG. 5 is a diagram showing a method for incorporating an iron core into a superconducting coil manufactured by the method for manufacturing a superconducting coil according to the present invention.

[Explanation of symbols]

1 ... Polyimide synthetic resin film tape, 2 ... Rectangular molded stranded wire, 4 ... Insulated conductor, 5 ... Epoxy resin tape, 6 ... Superconducting coil.

Claims (3)

[Claims] 1. A method for producing a superconducting coil, which comprises applying an adhesive to at least a part of one side of an insulated conductor having an outer periphery wound with a film tape in an overlapping manner, winding the wound conductor with a winding die, and heating with pressure. 2. A method for producing a superconducting coil, which comprises winding an insulating conductor wound in a winding manner and extruding it under pressure, excluding an adhesive-applied portion of a film tape having an adhesive applied on one side. 3. The method for producing a superconducting coil according to claim 1, wherein the superconducting coil heated under pressure is incorporated into the iron core by applying a pre-pressure.