JP2003197422A - Electromagnetic coil and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability in the interlayer insulation and insulation to the ground of an electromagnetic coil that is composed of a strand conductor to energize an AC and is used under environment exposed by radiation, and to provide a method for reducing the manufacturing cost. <P>SOLUTION: As a coil former used when a conductor is wound for forming winding, the member of a mold die used for resin impregnation is used, as it is, and the need for dismantling the coil former or the like is eliminated, after the wiring is formed. Additionally, the mold die is used as it is, as the case of an electromagnetic coil. As a result, outflow of resin after impregnation need not be considered, thus interposing a sufficient amount of resin between the conductors by using the resin having low viscosity, hence improving interlayer insulation and insulation to the ground. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic coil used for a radiation resistant electromagnet or the like, and more particularly to an insulating structure between conductors forming the electromagnetic coil and a method for realizing the insulating structure.

[0002]

2. Description of the Related Art Various accelerators are used to study the structure of atomic nuclei by accelerating charged elementary particles or ions to a high energy state and colliding them with a target. In this device, Lorentz force is used for accelerating elementary particles or ions and controlling the direction, so that it is necessary to install a large number of electromagnets for generating a high magnetic field. And
In an accelerator, generation of various kinds of radiation due to particle acceleration is unavoidable, and it is necessary to take measures against radiation in the electromagnet used.

For this reason, in consideration of deterioration of the insulator due to radiation, there has been disclosed a technique of constructing an electromagnetic coil using an inorganic insulating metal-coated cable called MIC (Mineral Insulated Cable). By the way, in the electromagnet, an alternating current may be used in order to generate a pulsed magnetic field, and it may be necessary to insulate with an organic polymer compound.

That is, it is necessary to use a strand conductor in order to reduce the eddy current loss caused by passing an alternating current. In this case, it is necessary to secure insulation between the strand conductors in the winding. As a matter of course, the insulation between the wires constituting the strand conductor also contributes to the loss reduction.

In addition, since the coil vibrates when an alternating current is applied, the insulator is required to have a certain degree of flexibility. Further, if there is a space between the conductors, the space causes cracks in the insulator. In other words, it is necessary to have fluidity that allows smooth filling between conductors and insulation using a flexible material that is not found in inorganic materials. As a material having such characteristics, a thermosetting polymer material that exhibits a certain fluidity before curing and has a certain flexibility after curing can be mentioned.

The coil manufacturing process for insulation using the thermosetting polymer material is as follows. First, in order to ensure insulation between the strand conductors, a tape made of glass fiber is horizontally wound on a prepreg (hereinafter referred to as a prepreg) impregnated with a polyimide resin before curing. That is, the prepreg is continuously spirally wound around the strand conductor, and after being wound, the polyimide resin is cured by heating. At this time, the prepregs are wound so that one half of the width of the prepregs overlaps with each other, so that the insulation has a thickness of two prepreg layers.

Next, the strand conductor that has been subjected to the insulation treatment as described above is wound into a required shape and the number of turns to form a winding. Then, the winding is dipped in a container filled with polyimide resin before curing for a certain period of time, between the strand conductors,
A polyimide resin is filled between the wires forming the strand conductor.

Next, the winding is pulled up from the container, and the prepreg is wound horizontally to cure the polyimide resin. Here, the reason why the polyimide resin is used as the insulating material is that, among the polymer materials, the polyimide resin is least deteriorated when exposed to radiation.

However, in the above manufacturing process, the outflow of the polyimide resin becomes a problem. Since the polyimide resin used here retains thermoplasticity in the stage before the curing reaction proceeds, its viscosity coefficient is lowered by heating. Specifically, for hardening,
Since it is heated up to around ℃, the polyimide resin is 10cP
The viscosity coefficient decreases to some extent, and the physical properties are virtually the same as water.

Further, in the step of winding the above-mentioned strand conductor to form a winding, the required winding shape is obtained by an operation of laying the strand conductor along the winding die or pressing it, and from the outside, appropriately. It is general to hold the shape of the winding by using a clamp or the like, but it is necessary to disassemble these winding forms and clamps at the time of impregnation with the polyimide resin. At this time, in order to maintain the shape of the winding, it is necessary to perform heat treatment on the winding and fuse the prepreg before disassembling the winding form or the clamp.

However, the above-mentioned fusion-bonding operation closes the gaps between the layers of the horizontally wound prepreg, and during the impregnation work in the next step, the gaps between the strands constituting the strand conductors and the strand conductors. As a result, it becomes difficult for the polyimide resin to permeate into the spaces between them.

[0012]

In the impregnation step due to the above-mentioned obstacle, not only the polyimide resin does not sufficiently penetrate into the gap between the conductors but also the polyimide resin flows down at the stage of curing treatment.
There is a risk that sufficient insulation cannot be ensured between the conductors and that various obstacles may occur due to the voids formed between the conductors. Therefore, the technical problem of the present invention is to solve the above problems and improve the reliability of an AC electromagnet using a strand conductor.

[0013]

The present invention was made as a result of reexamination of the whole manufacturing process, particularly the impregnation process of a polyimide resin, in order to solve the above problems.

That is, according to the present invention, a first step of horizontally winding a prepreg obtained by impregnating a glass fiber tape obtained by removing boron with a polyimide resin on a strand conductor, and a strand conductor obtained by horizontally winding the prepreg. A second step of winding to form a winding, a third step of impregnating the winding with a polyimide resin, a fourth step of curing the polyimide resin, and a terminal treatment of the winding. In the method for manufacturing an electromagnetic coil including the fifth step of applying, the second step of forming the winding includes at least one of members constituting a mold used for impregnating the polyimide resin in the third step. The method is a method for manufacturing an electromagnetic coil, characterized in that the portion is used as a winding die for winding the strand conductor.

Further, according to the present invention, in the method of manufacturing an electromagnetic coil, the mold used in the third step is
A method for manufacturing an electromagnetic coil, which is used as a case of a winding.

The present invention is also the method for manufacturing an electromagnetic coil as described above, wherein the strand conductor is made of at least one of copper and aluminum.

The present invention is also the method of manufacturing an electromagnetic coil as described above, wherein the strand conductor has a pipe for passing cooling water.

Further, the present invention is a winding formed of a strand conductor obtained by horizontally winding a prepreg made by impregnating glass fiber obtained by removing boron with a polyimide resin,
A case that doubles as a winding die of the winding and a resin-impregnated mold, a gap between strands forming the strand conductor, a gap between strand conductors forming the winding, and a gap between the winding and the case. It is an electromagnetic coil obtained by the above-mentioned manufacturing method, characterized in that it is made of a polyimide resin filled in.

[0019]

In the present invention, the winding die used in the winding process is
Since it is used as it is for a mold for impregnating a polyimide resin, it is not necessary to fuse a prepreg for maintaining the shape of the winding. For this reason, the impregnation property between the conductors of the polyimide resin is improved. The polyimide resin used here may be filled with inorganic powder for the purpose of adjusting fluidity and reinforcing. In that case, silica is preferable as the material in consideration of supply stability and chemical stability,
Considering the fluidity of the resin, the average particle size is 1.5
It is desirable that the thickness is less than or equal to μm and the filling rate is 5 to 15% by weight.

Further, in such an electromagnetic coil,
In order to improve the reliability of the ground insulation, the prepreg may be wound horizontally on the outer circumference of the winding. As in the present invention, in the manufacturing method in which the winding is integrated with the winding die and impregnated with the polyimide resin, horizontal winding around the winding is substantially impossible. However, this problem can be dealt with by subjecting the surface on the side where the windings are arranged, such as a mold used for filling the polyimide resin, that is, a winding mold, in advance to ensure insulation.

Specifically, it is possible to apply an insulative coating to a required thickness, dispose a planar insulator, and attach a prepreg to a required thickness. Also,
A block-shaped pillar made of an insulating material is placed on the side where the winding wire of the winding form is arranged so that a certain distance is maintained between the winding form and the winding wire, and the gap is filled with resin. Of course, it is okay.

Further, in the present invention, the glass fiber tape used for the prepreg does not contain boron because boron absorbs thermal neutrons and damages the surrounding glass fibers and polyimide resin. Is. That is, boron has an atomic weight of 10 ( ¹⁰ B) and 11 ( ¹¹ B) at a ratio of 19.9 / 80.1, but when ¹⁰ B absorbs thermal neutrons, it becomes a recoil particle. α rays and ⁷ Li are generated, and the range of each is 5 μm,
This is because the thickness of 2 μm affects the surrounding substances.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described with reference to the drawings with reference to specific examples.

FIG. 1 is a cross-sectional view of a strand conductor used in the present invention, showing a state in which a prepreg 103 is horizontally wound on a strand conductor 100 in which strands 101 made of oxygen-free copper are twisted together. In this conductor, a cooling water passage pipe 102 made of stainless steel is arranged at the center.

FIG. 2 is a perspective view showing a state in which the prepreg is horizontally wound on the strand conductor. As shown in FIG. 2, here, the prepreg 201 is spirally wound around the strand conductor 200 so that half of the width of the prepreg overlaps.

FIG. 3 is a view showing a state in which the strand conductor wound in the horizontal direction of the prepreg is wound, and FIG.
Is a perspective view, and FIG. 3B is a sectional view. The winding form 302 used here is made of non-magnetic stainless steel,
04 and a collar portion 305. Then, a winding is formed with the strand conductor 301 along the winding frame 304. An insulating layer 303 formed by applying and curing a polyimide resin is previously provided on the surface of the winding die 302 on the side in contact with the strand conductor.

FIG. 4 is a cross-sectional view showing a state in which a strand conductor is wound around a winding die, required members are attached, and a mold die for filling with a polyimide resin is assembled. As shown in FIG. 4, here, a winding form 402 around which a strand conductor 401 is wound, and a member 40 to be a side plate are provided.
4 and a member 405 serving as a lid are attached using a bolt 406 and a nut (not shown), and the whole is formed into one container.

A member 404 that serves as a side plate and a member 4 that serves as a lid.
An insulating layer 403 is formed on the surface of the wire 05, which is in contact with the winding wire, similarly to the winding die. Although bolts and nuts are used for assembling each member, it goes without saying that a female screw may be preliminarily cut at a required position of each member. If possible, the members may be joined by welding.

FIG. 5 is a perspective view schematically showing a state in which the winding is covered with a mold and the end of the winding is pulled out from the opening of the mold. In FIG. 5, reference numeral 501 is the end of the winding, 502 is the opening of the mold, and 503 is the mold.

Next, after depressurizing the inside of the mold with a vacuum pump to treat the polyimide resin so that the polyimide resin sufficiently penetrates into the voids, the polyimide resin was injected. After the impregnation operation, the inside of the container was pressurized with a pressure of 150 kPa to sufficiently infiltrate the polyimide resin into the gap between the conductors. Then, using a high temperature tank, pre-curing and post-curing of the polyimide resin were carried out under the conditions of 120 ° C. × 6 hours and 150 ° C. × 4 hours, respectively. After that, a bus bar was attached to energize this winding, and a pipe component for passing cooling water was attached to form an electromagnetic coil.

FIG. 6 is a perspective view showing the appearance of a completed electromagnetic coil. In FIG. 6, 601 is a strand conductor,
602 is a water passage pipe, 603 is a polyimide resin, 60
4 is a mold type, and 605 is a bus bar. Also, 60
An insulating terminal 6 has a function of preventing leakage of current to the mold 604.

[0032]

As described above, according to the present invention, in the process of manufacturing an electromagnetic coil which is used in an environment exposed to radiation and which is formed of a strand conductor for energizing alternating current, By using the winding die used for winding the same as the molding die for filling the resin, it is possible to obtain an electromagnetic coil having excellent interlayer insulation and ground insulation characteristics.

Moreover, in the electromagnetic coil of the present invention,
Since the resin is filled between the strands of the strand conductor to ensure the insulation between the strands, the loss due to the eddy current can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a strand conductor used in the present invention.

FIG. 2 is a perspective view showing a state in which a prepreg is horizontally wound on a strand conductor.

FIG. 3 is a view showing a state in which a strand conductor wound in a horizontal direction of a prepreg is wound, FIG. 3 (a) is a perspective view, and FIG.
(B) is a sectional view.

FIG. 4 is a cross-sectional view showing a state in which a mold die for filling a resin is assembled.

FIG. 5 is a perspective view schematically showing a state in which an end of a winding is pulled out from an opening of a mold.

FIG. 6 is a perspective view showing the appearance of a completed electromagnetic coil product.

[Explanation of symbols]

100, 200, 301, 401, 601 Strand conductor 101 Strands 102, 602 Water pipe 103, 201 Prepreg 302, 402 Winding form 303, 403 Insulating layer 304 Winding frame part 305 Collar part 404 Side plate member 405 Becomes lid Member 406 Bolt 501 Winding end 502 Mold opening 503, 604 Mold 603 Polyimide resin 605 Bus bar 606 Insulating end

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5E044 AA07 AC01 AC06 AD02 CA08                       CB01                 5E048 CB01 CB07

Claims (5)

[Claims] 1. A first step of horizontally winding a prepreg obtained by impregnating a glass fiber tape obtained by removing boron with a polyimide resin around a strand conductor, and winding and winding a strand conductor obtained by horizontally winding the prepreg. Second forming a line
Of the electromagnetic coil, the third step of impregnating the winding with a polyimide resin, the fourth step of hardening the polyimide resin, and the fifth step of applying a terminal treatment to the winding. In the manufacturing method, the second step of forming the winding is the step of winding at least a part of the member forming the mold used for the impregnation of the polyimide resin in the third step when the strand conductor is wound. A method for manufacturing an electromagnetic coil, which is used as a winding form. 2. The method of manufacturing an electromagnetic coil according to claim 1, wherein the mold used in the third step is used as a case of a winding. 3. The method for manufacturing an electromagnetic coil according to claim 1 or 2, wherein the strand conductor is made of at least one of copper and aluminum. 4. The method of manufacturing an electromagnetic coil according to claim 1, wherein the strand conductor has a pipe for passing cooling water. Method. 5. A winding formed of a strand conductor obtained by horizontally winding a prepreg made by impregnating glass fiber obtained by removing boron with a polyimide resin, a winding form of the winding and a resin-impregnated mold. And a gap between strands forming the strand conductor, a gap between strand conductors forming the winding, and a polyimide resin filled in the gap between the winding and the case. An electromagnetic coil obtained by the manufacturing method according to any one of claims 1 to 4.