JPH0645137A - Coil for electromagnet and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To manufacture the title coil for electromagnet capable of using an especially fine strand as a conductor as well as externally force-cooling down with high magnetic field precision. CONSTITUTION:The title manufacturing method is composed of the two steps enumerated as follows i.e., the first step of winding a flexible insulating pipe 3 for previously running a cooling medium around a mold so that a resin 5 containing a filler may be cast molded in a cavity inside the mold excluding the hollow part 4 to be set for molding a resin cast molded body and the second step of integrating the resin cast molded body with electric insulated coils 6 by taking the cast molded body out of the mold and then containing said coil 6 made of previously wound up conductors in the state of being arranged near the insulating pipe 3 in another mold and casting a resin to be set later.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a coil for an electromagnet, which has a large resistance loss of a conductor and a large amount of heat generation, is generally shown in FIG.
As shown in FIG. 3, a conductor 1 having a hollow portion 2 is used, and the hollow portion 2 of the conductor 1 is cooled by flowing a cooling medium such as water.

[0003]

However, the electromagnet coil having such a structure generally has a large conductor diameter,
Especially when using a thin wire twisted 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.

The present invention has been made in order to solve the above-mentioned problems, and its purpose is to use a twisted thin wire as a conductor, and to forcibly cool it from the outside. To provide a coil for an electromagnet having high magnetic field accuracy and a method for manufacturing the same.

[0005]

In order to achieve the above object, the present invention provides a cylindrical resin-filled resin casting having an insulating pipe for flowing a cooling medium therein, and the vicinity of the insulating pipe. In this case, a conductor wound in advance is disposed on the inner surface of the resin cast product, and an electromagnetic coil is integrated with the resin cast product by a resin.

Further, 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 the void in the mold except for the hollow portion of the pipe. In a state where an electrically insulated coil formed by curing and molding a resin cast product, then taking out this cast product and winding a conductor in advance near the insulating pipe, is separated from the above. A resin is injected into a mold and cured to integrate the electrically insulated wire loop with the resin casting.

[0007]

In such an electromagnet coil and its manufacturing method, heat generated due to resistance loss of a conductor is passed through a cooling medium such as water or oil through an insulating pipe to form a very thin wire or a twisted wire. Even when used as a conductor, it can be easily cooled. Also, because an insulating pipe is used,
There is no eddy current loss, and since the electrical insulation coil is fixed with resin, there is no fluctuation in the magnetic field and the dimensional accuracy is high.
Moreover, an electromagnet with high magnetic field accuracy can be obtained. Furthermore, since the insulating pipe is less likely to be damaged and the cooling medium does not leak, a highly reliable electromagnet can be obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view showing a structural example for explaining a method of manufacturing an electromagnet coil according to the present invention. In the present embodiment, as shown in FIG. 1, a flexible insulating pipe 3 for flowing a cooling medium is wound around a mold (not shown) in advance, and the hollow portion 4 of the pipe is removed in the cavity of this mold. Then, a resin 5 such as an epoxy resin containing a powder of silica, alumina, glass or the like or a filler made of fibers is cast and cured. Next, the casting 12 is taken out of the mold, and in a state in which an electrically insulating coil 6 formed by winding a conductor in advance is arranged in the vicinity of the insulating pipe 3, the casting 12 is put in another mold not shown and the resin 7
Is cast and cured to be integrated. Then, the mold is removed to obtain the electromagnet coil.

The insulating pipe 3 is used as follows.
This is because the eddy current is not induced and the accuracy of the magnetic field is maintained. The flexible pipe is used so that it can be wound in any shape.

Here, examples of the insulating pipe 3 include polytetrafluoroethylene (tetrafluoroethylene resin), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (ethylene tetrafluoride / perfluoroalkoxyethylene copolymer). Polymer), tetrafluoroethylene-hexafluoropropylene copolymer (tetrafluoroethylene / hexafluoropropylene / perfluoroalkoxyethylene copolymer), tetrafluoroethylene-
Ethylene copolymer (tetrafluoroethylene / ethylene copolymer resin), tetrafluoroethylene-ethylene copolymer (tetrafluoroethylene / ethylene copolymer resin), polychlorofluoroethylene (trifluorochloroethylene resin), chloro Pipes made of fluororesin such as trifluoroethylene-ethylene copolymer (trifluoroethylene chloride / ethylene copolymer resin), polyvinylidene fluoride (vinylidene fluoride resin), polyvinyl fluoride (vinyl fluoride resin) are used. It has the property of not adhering to the injected resin.

As shown in FIG. 2 instead of the above pipe, for example, on the polymer pipe 9 having heat resistance, water resistance and oil resistance, such as the above-mentioned fluororesin, polyetheretherketone, ethylenepyropyrene rubber, etc. Alternatively, a double pipe 8 may be used in which a heat-shrinkable tube 10 made of polyethylene terephthalate, polytetrafluoroethylene, or the like is coated, and the tube is heated to shrink the tube 10 so as to be in close contact with the polymer pipe 9. Further, as shown in FIG. 3, for example, an insulating resin 1 made of glass or polyester on the surface
A polymer pipe 9 having a heat resistance, a water resistance, and an oil resistance, such as polytetrafluoroethylene, polyether ether ketone, and ethylene propylene rubber braided with No. 1 may be used.

In this way, as the insulating pipe 3, for example, a pipe that does not adhere to the resin to be injected, such as a fluororesin such as polytetrafluoroethylene or tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer,
By using double pipes or polymer pipes such as polytetrafluoroethylene, polyether ether ketone, ethylene propylene rubber, etc. with glass or polyester fibers braided on the surface, which have heat resistance, water resistance, and oil resistance Even if it contracts and cracks when it hardens, it will prevent the cooling medium from flowing out from the cracks when the cracks propagate in the pipe and later flow a cooling medium such as water or oil. This is because you can

That is, by using as the insulating pipe 3 a pipe that does not adhere to the resin to be injected, such as a fluororesin such as polytetrafluoroethylene or tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, cracks will occur in the resin. Even if the crack occurs, the crack does not penetrate the pipe and can propagate along the interface between the pipe and the resin. If the double pipe 8 as shown in FIG. 2 is used, even if the outer pipe, for example, the tube 10 is cracked, the polymer pipe 9 will not be cracked. Further, as shown in FIG. 3, for example, a polymer pipe 9 having heat resistance, water resistance, and oil resistance, such as polytetrafluoroethylene, polyetheretherketone, and ethylene-propylene rubber, in which glass or polyester fibers 11 are braided on the surface. By using, it is possible to prevent cracks generated in the resin by relaxing the stress in the braided portion.

In the electromagnet coil manufactured as described above, the resin is injected while the electrically insulated coil 6 around which the conductor is wound is arranged in the vicinity of the flexible insulating pipe 3. Since it is hardened and integrated, by flowing a cooling medium such as water or oil into the insulating pipe 3, the heat due to the resistance loss generated by the electrically insulating coil 6 is efficiently transferred to the cooling medium and removed. can do. Therefore, the temperature of the electrically insulated coil can be kept low, and deterioration of the insulating material is less likely to occur.

Further, the insulating pipe 3 is cast into a void portion excluding the inside 4 of the pipe, and a resin 5 such as epoxy with a filler made of powder or fibers of silica, alumina, glass or the like is cast and cured, and then the mold is removed from the mold. Even if it is taken out, the resin containing the filler has a small shrinkage rate upon curing, and the cured resin has high mechanical strength, so that cracks are unlikely to occur in the resin, 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, the method for manufacturing the coil for electromagnet according to the present invention will be described in detail with reference to specific examples.

First, a flexible insulation made of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer having an inner diameter of 5 mm and an outer diameter of 7 mm so as to come into contact with a steel mandrel having a surface coated with a release material. A spiral pipe is wound into a spiral shape, and 10 parts of silica powder is added to 100 parts by weight of a composition including an epoxy resin and an acid anhydride curing agent.
A cylindrical filler having a filler-containing resin (for example, TCG-1930 manufactured by Toshiba Chemical Co., Ltd.) mixed with 0 to 350 parts by weight, heat-cured, and having an insulating pipe 3 inside as shown in FIG. A resin casting 12 made of the filled resin 5 is molded.

The insulating pipe is spiral.
Since the insulating spacers are used for positioning when winding the product into a shape, the position of the insulating pipe does not shift during winding or casting.

Further, the surface of the completed resin casting 12 containing the cylindrical filler is roughened with sand paper or the like so that it can be easily adhered to the resin to be impregnated in a later step. Two types of resin castings 12 containing the cylindrical filler having different inner and outer diameter dimensions are prepared.

Next, separately, a fine wire in which an enamel film made of polyesterimide is coated on the surface of electrolytic copper having a diameter of 50 μm is twisted to form a flat stranded wire having a cross section of 4 mm × 10 mm, and an epoxy is applied from above. The varnish is applied to a glass tape and the semi-cured prepreg insulating tape is blown off and wound to obtain the insulated conductor 13 shown in FIG. This insulated conductor 1
5 has a groove 14 on the surface as shown in FIG. 5, polytetrafluoroethylene is baked on the surface, and is wound into a semi-cylindrical steel winding mold 15 having a mold release treatment in two layers. In this case, the height of the wound insulated conductor 13 is set to be 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 on one side is placed so that the adhesive faces the insulated conductor side. Arrange. Further, from above, the surface of the plate 17 whose surface is baked with polytetrafluoroethylene for release treatment.
Then, pressure is applied to the plate 17 with a press while heating the whole, and the prepreg insulating tape and the semi-cured adhesive are cured. 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 winding die 15 to obtain a saddle-shaped coil adhered to the insulating plate as shown in FIG.

In addition, an insulating plate to which an insulated conductor having another shape is adhered is obtained by the same method using a winding die in which another shape is dug. Two saddle-shaped coils (hereinafter referred to as A, B, and C coils) of three types each bonded to the insulating plate in this manner are prepared.

Next, a cylindrical steel mandrel whose surface is baked with polytetrafluoroethylene and subjected to a mold release treatment is prepared. A glass cloth sheet having a thickness of 0.13 mm is wound 10 times on this surface while tension is applied. On top of this, the three types of saddle-shaped coils adhered to the insulating plate obtained above,
As shown in FIG. 7, first, each one of the A coils is arranged at a symmetrical position with a 180 ° position offset on the circumference of the mandrel.

Next, of the two cylindrical resin-filled resin castings 12 having an insulating pipe and having a smaller inner / outer diameter, the one having the smaller inner / outer diameter is inserted from the above, and then B Similarly, one coil is arranged at each symmetrical position on the mandrel's circumference, offset by 180 °. From this, a glass cloth sheet having a thickness of 0.13 mm is wound 10 times with tension applied. From the outside, the surface is baked with polytetrafluoroethylene, and a mold having a release treatment is attached and sealed. Both ends of the insulating pipe are tightly plugged so that the resin does not enter the pipe during impregnation in a later step.

Next, the whole is carried into a decompression container, the voids in the mold are decompressed by a vacuum pump, the acid anhydride curing agent and the resin 7 consisting of the epoxy resin composition are fed, and then the resin is pressurized to remove the resin. Impregnate. After that, the resin is heated and cured. Thus, when the heat curing is completed, the mold is removed, and then the mandrel is removed to obtain an electromagnet coil as shown in the sectional view of FIG.

As in the above-mentioned specific example, the cylindrical resin-filled resin casting 12 having an insulating pipe therein is used as the insulated conductor 1.
After the resin is placed in the vicinity of 3, and the resin is impregnated and cured, the cured resin material 12 containing the filler has a small curing shrinkage rate and the cured resin has a large mechanical strength, so that the resin is less likely to crack, and the insulation There is no risk of damaging the cooling pipe and the risk of leakage of the cooling medium. Further, since the resin containing the filler is used, the thermal conductivity of the resin is high and the cooling efficiency is improved. Further, since the wound electrically insulating coil 6 is placed in the vicinity of the insulating pipe, the resin is cast, hardened, and integrated, heat generated by the resistance loss generated by the electrically insulating coil 6 is removed. It is possible to efficiently transfer and remove the cooling medium. Therefore, the temperature of the electrically insulated coil can be kept low and the thermal stress can be lowered, so that the deterioration of the insulating material is less likely to occur and a highly reliable coil for an electromagnet can be manufactured.

Here, the insulating pipe made of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer is spirally wound because the cooling medium such as water or oil is made to flow through this pipe later, and the electromagnet is electromagnetized. This is for cooling. Further, the insulating pipe is used because eddy current is induced in the metal and the loss increases and the accuracy of the magnetic field deteriorates. And, the insulating pipe made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer has the highest strength among the insulating pipes having the property of not adhering to the cast resin, and is less likely to cause loss, and cast. This is because it does not adhere to the resin, so that if a crack occurs in the resin, the crack does not penetrate the pipe and propagates along the interface between the pipe and the resin.

On the other hand, the reason why the stranded wire composed of a thin wire is used as the insulated conductor 13 is to reduce the eddy current loss and to easily wind a rectangular wire having a large cross-sectional area. In addition, the prepreg insulating tape is wound on the insulated conductor because the resin is melted and then cured by heating and pressurizing between the insulated conductors and between the insulated conductor and the insulating plate 16 made of an epoxy glass sheet. This is to bond the.

The reason why the prepreg insulating tape is skipped and wound is that the prepreg insulating tape is easily wound into a desired shape, and at the same time, a resin invasion path is secured when the resin later impregnates the voids into the voids.

Furthermore, after winding the glass cloth sheet on the surface of the mandrel and arranging the three types of saddle-shaped coils adhered to the insulating plate obtained above, the glass cloth sheet is wound from above. The reason is that the insulated conductor is fixed and the conductor is insulated by impregnating and hardening the resin later. The FRP 18 made of glass cloth sheet and epoxy resin is formed inside and outside the coil, and a mechanically strong structure is completed. Therefore, even if the mandrel is removed, it has a mechanical strength enough to maintain an integral structure as an electromagnet.

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, the eddy current is not induced and the accuracy of the magnetic field does not deteriorate. Furthermore, since an insulating pipe made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer is used, it does not adhere to the impregnated resin, so even if a crack occurs in the resin, the crack does not penetrate the pipe and the cooling medium is There is no leakage to the outside.

Further, since a groove is formed in the mold and the insulated conductor is wound in the groove, an electromagnet having a high coil dimensional accuracy and a high magnetic field accuracy can be obtained. Further, by preparing one winding mold and one mold having different sizes, a large number of coils have the same accuracy, and the complicated work of winding the insulated conductor while inserting the insulating spacer as in the conventional case is performed. The coil can be manufactured without

In the above-mentioned embodiment, the cylindrical resin-filled resin casting having the insulating pipe is arranged in the vicinity of all the insulating coils. However, the insulating property is provided only in the vicinity of the insulating coils having a high temperature. A cylindrical filler-filled resin casting having a pipe may be arranged.

[0034]

As described above, according to the electromagnet coil and the method of manufacturing the same according to the present invention, a flexible insulating pipe for flowing a cooling medium is wound around a mold in advance,
A resin filled with a filler was cast into the cavity of the pipe excluding the hollow part of the pipe, the resin was cured, and the wound electrical insulation coil was placed in the vicinity of the insulating pipe. Since it was made to integrate by casting resin in the mold and curing it, heat generated by resistance loss of the conductor was passed through a pipe such as water or oil, and a very thin wire, Alternatively, even if a stranded wire is used as the conductor, it can be cooled easily. In addition, since an insulating pipe is used, eddy current loss does not occur, and since the electric insulating coil is fixed with resin, the magnetic field does not fluctuate, the dimensional accuracy is high, and the magnetic field accuracy is high. Can be obtained. Furthermore, since the insulating pipe is less likely to be damaged and the cooling medium does not leak, a highly reliable electromagnet can be obtained.

[Brief description of drawings]

FIG. 1 is a 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 resin casting with a cylindrical filler, which has an insulating pipe inside, used in the present invention.

FIG. 5 is an explanatory view for explaining a step of adhering 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 that has been conventionally used in a forced cooling type coil.

[Explanation of symbols]

1 ... Conductor, 2 ... Hollow part, 3 ... Insulating pipe, 4 ...
… In the pipe, 5 …… filled resin, 6 …… electrically insulated wire, 7 …… resin, 8 …… double pipe, 9 …… polymer pipe, 10 …… heat-shrinkable tube, 11… ... Insulating fiber, 12 ... Cylindrical filler-containing resin casting having an insulating pipe inside, 13 ... Insulated conductor, 14 ... Groove, 15
...... Roll form, 16 …… Insulation plate, 17 …… Plate, 18 …… FRP consisting of glass cloth and epoxy resin.

Claims (2)

[Claims] 1. A cylindrical resin casting containing a filler having an insulating pipe through which a cooling medium flows, and a conductor pre-wound on the inner surface of the resin casting near the insulating pipe. A coil for an electromagnet, comprising: an electromagnetic coil provided and integrated with the resin casting by a resin. 2. 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 of the mold except for a hollow portion of the pipe to cure the resin. To form a resin cast product, and then remove the cast product from the mold and preliminarily wind a conductor and arrange an electrically insulating coil in the vicinity of the insulating pipe. A method for manufacturing a coil for an electromagnet, characterized in that the electric insulating coil is integrated with the resin casting by injecting a resin into the resin and curing the resin.