JP2622053B2 - Manufacturing method of coil for electromagnet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electromagnet coil having a cooling structure using a cooling medium.

[0002]

2. Description of the Related Art Conventionally, in an electromagnet coil having a large resistance loss and a large amount of heat generation in a conductor, generally, for example, FIG.
As shown in FIG. 1, a conductor 1 having a hollow portion 2 is used, and cooling is performed by flowing a cooling medium such as water through the hollow portion 2 of the conductor 1.

[0003]

However, an electromagnet coil having such a structure generally has a large conductor diameter.
Especially when using a thin twisted wire as a conductor,
It was impossible to make this thin wire hollow, and even if a hollow wire was made, it was impossible to twist it.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a purpose of the present invention is to make it possible to use a thin twisted wire as a conductor and to perform forced cooling from the outside. Coil with high magnetic field accuracy
It is to provide a manufacturing method of.

[0005]

[0006]

The present invention achieves the above objects.
In order to achieve this, a flexible insulating pipe for flowing a cooling medium is wound around a mold in advance , and a resin containing a filler is cast into a cavity in the mold except for the hollow portion of the pipe, and cured. To form a resin casting, and then remove the casting from the mold, and place an electrically insulated wire loop in which a conductor is wound in advance in the vicinity of the insulating pipe, and separate the mold from the mold. And the resin is injected and cured to integrate the electrically insulated wire loop into the resin casting.

[0007]

In such a method for manufacturing a coil for an electromagnet, heat generated by resistance loss of a conductor is passed through an insulating pipe through a cooling medium such as water or oil, so that a very thin wire or a stranded wire is converted into a conductor. Can be easily cooled. In addition, the use of an insulating pipe eliminates the occurrence of eddy current loss, and furthermore, since the electrically insulated wire is fixed with resin, there is no fluctuation in the magnetic field, high dimensional accuracy, and an electromagnet with high magnetic field accuracy. Can be obtained. Furthermore, since the insulating pipe is hardly damaged and the cooling medium does not leak, a highly reliable electromagnet can be obtained.

[0008]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an example of a structure for explaining a method of manufacturing an electromagnet coil according to the present invention. In this embodiment, as shown in FIG. 1, a flexible insulating pipe 3 for previously flowing a cooling medium is wound around a mold (not shown), and a hollow portion 4 of the pipe is removed in a gap of the mold. Then, a resin 5 such as a powder of silica, alumina, glass or the like or an epoxy or the like containing a filler made of fiber is cast and cured. Next, the casting 12 is taken out of the mold, and in a state where the electrically insulated wire loop 6 formed by winding a conductor is arranged in the vicinity of the insulating pipe 3, the casting is placed in another mold (not shown) and the resin
Are integrated by curing and curing. Thereafter, the mold is removed to obtain an electromagnet coil.

The reason why the insulating pipe 3 is used is as follows.
This is to maintain the accuracy of the magnetic field without inducing an eddy current. The reason why the flexible pipe is used is that the pipe can be wound in any shape.

The insulating pipe 3 is made of, for example, polytetrafluoroethylene (tetrafluoroethylene resin) or a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (tetrafluoroethylene / perfluoroalkoxyethylene copolymer). Copolymer), tetrafluoroethylene-hexafluoropropylene copolymer (ethylene tetrafluoride / polypropylene hexafluoride / perfluoroalkoxyethylene copolymer), tetrafluoroethylene-
Ethylene copolymer (ethylene tetrafluoride / ethylene copolymer resin), tetrafluoroethylene-ethylene copolymer (ethylene tetrafluoride / ethylene copolymer resin), polychlorofluoroethylene (ethylene trifluoride chloride resin), chloro Pipes made of fluorine resin such as trifluoroethylene-ethylene copolymer (ethylene trifluoride / ethylene copolymer resin), polyvinylidene fluoride (vinylidene fluoride resin), polyvinyl fluoride (vinyl fluoride resin) are used. And does not adhere to the injected resin.

As shown in FIG. 2 in place of the above-mentioned pipe, a polymer pipe 9 having heat resistance, water resistance and oil resistance such as the above-mentioned fluororesin, polyether ether ketone, ethylene propylene rubber or the like is used. For example, a double pipe 8 in which a heat-shrinkable tube 10 of polyethylene terephthalate, polytetrafluoroethylene, or the like is coated, and this tube is shrunk by heating to adhere to a polymer pipe 9 may be used. Further, as shown in FIG. 3, for example, an insulating resin
A polymer pipe 9 having heat resistance, water resistance, and oil resistance, such as polytetrafluoroethylene, polyether ether ketone, or ethylene propylene rubber, obtained by braiding 1 may be used.

As described above, the insulating pipe 3 is a pipe which does not adhere to a resin to be injected, such as a fluororesin such as polytetrafluoroethylene or a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer.
The use of double-pipe or heat-, water- and oil-resistant polymer pipes such as polytetrafluoroethylene, polyetheretherketone, and ethylene-propylene rubber with glass or polyester fibers braided on the surface, Even if the pipe shrinks and cracks when it cures, the crack will grow in the pipe and prevent the cooling medium from flowing out of this crack to the outside when a cooling medium such as water or oil is flowed later. This is because

That is, by using a pipe that does not adhere to the resin to be injected, such as a fluororesin such as polytetrafluoroethylene or tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, as the insulating pipe 3, cracks are formed in the resin. Even if cracks occur, the crack does not penetrate the pipe, and can propagate along the interface between the pipe and the resin. Further, if a double pipe 8 as shown in FIG. 2 is used, even if an outer pipe such as the tube 10 is cracked, the crack does not develop in the polymer pipe 9. Further, as shown in FIG. 3, a polymer pipe 9 made of, for example, polytetrafluoroethylene, polyether ether ketone, ethylene propylene rubber, or the like, which is braided with glass or polyester fibers 11 on its surface, has heat resistance, water resistance, and oil resistance. By using, the cracks generated in the resin can be prevented by relaxing the stress in the braided portion.

In the electromagnet coil manufactured in this manner, resin is injected while the electrically insulated wire loop 6 around which the conductor is wound is arranged near the flexible insulating pipe 3. The cooling medium such as water and oil flows through the insulating pipe 3 to efficiently transfer and remove the heat due to the resistance loss generated by the electrically insulated wire 6 to the cooling medium. can do. Therefore, the temperature of the electrically insulated wire ring can be kept low, and deterioration of the insulator is less likely to occur.

Further, the insulating pipe 3 is poured into a cavity other than the inside of the pipe 4 by pouring a resin 5 such as a powder of silica, alumina, glass or the like or an epoxy or the like containing a filler made of fiber, and then hardening. Even when the resin is taken out, the resin containing the filler has a small shrinkage ratio upon curing and the cured resin has a large mechanical strength, so that the resin is hardly cracked, the insulating pipe 3 is damaged and the cooling medium leaks out. There is no fear. Moreover, since the resin containing the filler is used, the thermal conductivity of the resin is high, and the cooling efficiency is improved. Next, a method for manufacturing an electromagnet coil according to the present invention will be described in detail with reference to specific examples.

First, a flexible insulating material made of a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer having an inner diameter of 5 mm and an outer diameter of 7 mm is in contact with a steel mandrel having a release material applied to its surface. Is wound in a spiral shape (spiral shape), and silica powder is added to 100 parts by weight of a composition comprising an epoxy resin and an acid anhydride curing agent.
A cylindrical filler having an insulative pipe 3 as shown in FIG. 4, which is cast with a filler-containing resin (for example, TCG-1930 manufactured by Toshiba Chemical Co., Ltd.) mixed with 0 to 350 parts by weight and cured by heating. To obtain a resin casting 12 made of resin 5
You .

Note that the insulating pipe is spirally wound.
By positioning using an insulating spacer when winding in a shape, the position of the insulating pipe does not shift during winding or casting.

Further, the surface of the completed resin injection product 12 containing a cylindrical filler is roughened with a sandpaper or the like so as to be easily adhered to a resin impregnated in a later step. Two types of resin injection products 12 having different cylindrical inner and outer diameters are prepared.

Next, a thin wire having an enamel coating made of polyesterimide coated on a surface of electrolytic copper having a diameter of 50 μm is twisted separately to form a rectangular stranded wire having a cross section of 4 mm × 10 mm. A varnish is applied to a glass tape and the prepreg insulating tape in a semi-cured state is skipped and wound to obtain an insulated conductor 13 shown in FIG. This insulated conductor 1
As shown in FIG. 5, No. 3 is wound in two layers on a semi-cylindrical steel mold 15 having a groove 14 on the surface, baking polytetrafluoroethylene on the surface, and performing a release treatment. In this case, the height of the wound insulated conductor 13 is slightly larger than the depth of the groove 14.

On top of this, an insulating plate 16 made of a flexible epoxy glass sheet having a thickness of 0.5 mm and having a semi-cured adhesive applied to one side is placed on the insulating plate 16 so that the adhesive faces the insulated conductor. Arrange. Further, from above, the plate 17 having its surface subjected to release treatment by baking polytetrafluoroethylene.
Then, pressure is applied to the pressing plate 17 with a press while heating the whole to cure the prepreg insulating tape and the semi-cured adhesive. Next, the contact plate 17 is removed, and the insulating plate 16 to which the insulated conductor 13 is adhered is taken out from the former 15 to obtain a saddle coil adhered to the insulating plate as shown in FIG.

Further, an insulating plate to which an insulated conductor having another shape is adhered is obtained by a similar method using a winding form engraved with another shape. Thus, two each of three types of saddle-shaped coils (hereinafter referred to as A, B, and C coils) bonded to the insulating plate are prepared.

Next, a cylindrical steel mandrel whose surface is subjected to a release treatment by baking polytetrafluoroethylene is prepared. A glass cloth sheet having a thickness of 0.13 mm is wound around the surface 10 times under tension. On top of this, three types of saddle coils bonded to the insulating plate obtained above,
As shown in FIG. 7, first, each one of the A coils is arranged at a symmetrical position shifted by 180 ° on the circumference of the mandrel.

Next, one of the two cylindrical resin-filled resin castings 12 having an insulating pipe provided therein, which has the smaller inner and outer diameters, is inserted. The coils are similarly arranged one by one at symmetrical positions shifted by 180 ° on the circumference of the mandrel. Next, from above
Prepared cylindrical filler with insulating pipe inside
Insert the larger of the inner and outer diameters of the two resin castings 12
And then put one C coil on each
At a symmetrical position shifted by 180 ° on the circumference of the
You. From above, a glass cloth sheet having a thickness of 0.13 mm is wound 10 times under tension. From the outside, the surface is baked with polytetrafluoroethylene, a mold that has been subjected to a mold release treatment is attached and hermetically sealed. The both ends of the insulating pipe are hermetically sealed so that the resin does not enter the pipe during the impregnation in a later step.

Next, the whole is carried into a decompression container, the space in the mold is depressurized by a vacuum pump, and a resin 7 composed of an acid anhydride curing agent and an epoxy resin composition is fed. Impregnate. Thereafter, the resin is heated and cured. After completion of the heat curing, the mold is removed, and then the mandrel is removed, thereby obtaining an electromagnet coil as shown in the sectional view of FIG.

As in the above specific example, the cylindrical resin-filled resin casting 12 having an insulating pipe therein is connected to the insulated conductor 1.
If the resin is impregnated and cured after being placed in the vicinity of 3, the cured resin-filled material 12 has a small curing shrinkage and a large mechanical strength of the cured resin, so that cracks are less likely to occur in the resin. The pipes are not damaged and there is no danger of leakage of the cooling medium. Further, since a resin containing a filler is used, the thermal conductivity of the resin is high, and the cooling efficiency is improved. Furthermore, since the wound electrically insulated wire 6 is placed in the vicinity of the insulating pipe, the resin is cast and hardened, and integrated, the heat due to the resistance loss generated by the electrically insulated wire 6 is reduced. It is possible to efficiently transmit and remove the cooling medium. Therefore, the temperature of the electrically insulated wire ring can be kept low and the thermal stress can be reduced, so that the insulator is less likely to deteriorate and a highly reliable electromagnet coil can be manufactured.

Here, the reason why the insulating pipe made of a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer is spirally wound is that a cooling medium such as water or oil is passed through this pipe later, This is for cooling. The reason why the insulating pipe is used is that an eddy current is induced in a metal, so that the loss increases and the accuracy of the magnetic field deteriorates. The insulating pipe made of a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer has the highest strength among the insulating pipes having the property of not adhering to the cast resin, is hardly lossy, and is cast. This is because if the resin does not adhere to the resin, the crack does not penetrate the pipe and propagates along the interface between the pipe and the resin even if the resin is cracked.

On the other hand, the reason why the stranded wire made of a fine wire is used as the insulated conductor 13 is to reduce eddy current loss and to make it easy to wind a rectangular wire having a large sectional area. The reason why the prepreg insulating tape is wound on the insulated conductor is that the resin is melted and cured by heating and pressing later and between the insulated conductors and between the insulated conductor and the insulating plate 16 made of an epoxy glass sheet. This is for bonding.

The reason why the prepreg insulating tape is skipped is to facilitate winding into a desired shape and to secure a resin infiltration path when the resin is later impregnated into the voids in the stranded wire.

Further, after a glass cloth sheet is wound on the surface of the mandrel, three kinds of saddle coils adhered to the insulating plate obtained above are arranged, and the glass cloth sheet is wound from above. The reason for this is to fix the insulated conductor and to insulate the conductor by impregnating the resin later and curing. Inside and outside of the coil are made of FRP 18 made of glass cloth sheet and epoxy resin, and a mechanically strong structure is completed. Therefore, even if the mandrel is removed, the electromagnet has a mechanical strength enough to maintain an integral structure.

In the electromagnet coil thus obtained, the electromagnet can be sufficiently cooled by flowing a cooling medium such as water or oil through the insulating pipe. Further, since the insulating pipe is used, no eddy current is induced and the accuracy of the magnetic field does not deteriorate. Furthermore, since an insulating pipe made of a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer was used, it did not adhere to the impregnated resin, so even if the resin cracked, the crack did not penetrate the pipe and the cooling medium It does not leak out.

Further, since a groove is dug in the mold and the insulated conductor is wound into the groove, an electromagnet having high dimensional accuracy of the completed coil and high magnetic field accuracy can be obtained. Also, by preparing one winding die and one die having different dimensions, a complicated work of winding the insulated conductor while inserting a large number of coils with the same accuracy and a conventional insulating spacer is performed. It is possible to manufacture a coil without any problems.

In the above-described embodiment, the resin casting with a cylindrical filler having an insulating pipe is arranged near all the insulated wires. A cylindrical filler-filled resin casting having a pipe may be arranged.

[0034]

As described above, the electromagnet according to the present invention
According to the method of manufacturing a coil for use, a flexible insulating pipe for flowing a cooling medium is wound around a mold in advance, and a resin containing a filler is poured into a cavity in the mold except for a hollow portion of the pipe. The mold is hardened, and the wound electric insulated wire is placed in the vicinity of the insulating pipe, and the resin is poured into the mold and cured to be unified with the one taken out of the mold. Therefore, even if a very thin wire or a stranded wire is used for the conductor, the heat generated by the resistance loss of the conductor can be easily cooled by passing a cooling medium such as water or oil through the pipe. In addition, the use of an insulating pipe eliminates the occurrence of eddy current loss, and furthermore, since the electrically insulated wire is fixed with resin, there is no fluctuation in the magnetic field, high dimensional accuracy, and an electromagnet with high magnetic field accuracy. Can be obtained. Furthermore, since the insulating pipe is hardly damaged and the cooling medium does not leak, a highly reliable electromagnet can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment for explaining an electromagnet coil and a method for manufacturing the same according to the present invention.

FIG. 2 is a sectional view showing a double pipe as an example of an insulating pipe used in the present invention.

FIG. 3 is a cross-sectional view showing a polymer pipe in which fibers are braided as another example of the insulating pipe used in the present invention.

FIG. 4 is a view showing a cylindrical resin-filled resin casting having an insulating pipe inside used in the present invention.

FIG. 5 is an explanatory diagram for explaining a step of bonding an insulated conductor to an insulating plate.

FIG. 6 is a diagram showing an insulated conductor bonded to an insulating plate.

FIG. 7 is a sectional view of an electromagnet manufactured by the method of the present invention.

FIG. 8 is a view showing a hollow conductor conventionally used in a forced cooling type coil.

[Explanation of symbols]

1 ... conductor, 2 ... hollow part, 3 ... insulating pipe, 4 ...
... in a pipe, 5 ... filled resin, 6 ... electrically insulated wire, 7 ... resin, 8 ... double pipe, 9 ... polymer pipe, 10 ... heat-shrinkable tube, 11 ... ... Insulating fiber, 12 ... Plastic cast resin with cylindrical filler inside having insulating pipe, 13 ... Insulated conductor, 14 ... Groove, 15
... winding form, 16 ... insulating plate, 17 ... this plate, 18 ... FRP made of glass cloth and epoxy resin.

Claims (1)

(57) [Claims] 1. A flexible insulating pipe for flowing a cooling medium is wound around a mold in advance, and a resin containing a filler is poured into a cavity in the mold except for a hollow portion of the pipe to be cured. To form a resin casting, and then remove the casting from the mold, and place an electrically insulated wire loop in which a conductor is wound in advance in the vicinity of the insulating pipe, and separate the mold from the mold. A method of manufacturing a coil for an electromagnet, wherein the electrically insulated wire is integrated with the resin casting by injecting and hardening a resin in the coil.