JPH04188708A - Manufacture of electromagnet coil - Google Patents

Abstract

PURPOSE:To ensure external forced cooling even when a thin stranded wire is employed as a conductor by winding a flexible insulating pipe in the vicinity of a wound electrically insulating coil, and putting the pipe in a die, and insulating resin in an air gap part excepting the inside of the pipe and curing the same and further integrally forming them. CONSTITUTION:A flexible insulating pipe 4 is wound in the vicinity of a wound electrically insulating coil 3. A resulting wound pipe is put in a die and resin 6 such as epoxy is injected into an air gap part excepting the inside of the pipe, and cured and integrated. Accordingly, by forcing a cooling medium such as water and oil to flow through the interior of the pipe wound in the vicinity of the wound electrically insulating coil 3, an electromagnet can effectively be cooled. Further, by the use of the insulating pipe 4 accuracy of a magnetic field can be kept without causing an eddy current, and since the flexible pipe is employed, the pipe can be wound adaptively to any configuration. Hereby, even with use of a fine line or a stranded wire as a conductor a resulting coil can easily be cooled.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method of manufacturing an electromagnetic coil.

(Conventional Technique til+i) Conventional electromagnet coils generate a lot of heat due to the large resistance loss of the sensitive body, and require cooling.

Generally, as shown in FIG. 7, for example, a hollow conductor 1 is wound to form a coil, and cooling is performed by flowing a cooling medium such as water into the hollow part 2.

(Problem to be solved by the invention) According to such conventional technology, the conductor generally becomes thicker,
In particular, when twisted thin wires were used as conductors, it was impossible to make the thin wires hollow, and even if hollow wires were made, it was impossible to twist them.

An object of the present invention is to provide a method for manufacturing an electromagnetic coil with high magnetic field precision, which uses twisted thin wires as a conductor and is forcedly cooled from the outside.

[Structure of the invention]

(Means for solving problems) In order to achieve the above object, the present invention has the following features.

A flexible insulating pipe wound around the wound electrically insulating wire is placed in a mold, and a resin such as epoxy is injected into the gap excluding the inside of the pipe and hardened to integrate.

Examples of insulating pipes include pipes that do not adhere to resins such as polytetrafluoroethylene, and double pipes such as polytetrafluoroethylene.

A tube made of heat-shrinkable polyethylene terephthalate or polytetrafluoroethylene is coated on top of a pipe made of a heat-resistant, water-resistant, oil-resistant polymer such as polyetherketone or ethylene propylene rubber, and the tube is heated. Double pipes that are shrunk and tightly attached to polymeric pipes, and heat-resistant and water-resistant materials such as polytetrafluoroethylene, polyetherketone, and ethylene propylene rubber with glass or polyester insulating fibers braided on the surface. Uses polymer pipes that are durable and oil resistant.

(Function) In the present invention, near the shaft of the electrically insulated wire wrapped once,
Since the flexible insulating pipe is wound, the electromagnet can be effectively cooled by later flowing a cooling medium such as water or oil into the pipe. Furthermore, by using an insulating pipe, the precision of the magnetic field can be maintained without inducing eddy currents. Furthermore, since a flexible pipe is used, it can be wound to fit any shape.

Insulating pipes such as pipes that do not adhere to resin such as polytetrafluoroethylene, double pipes, or polytetrafluoroethylene with glass or polyester fibers braided on the surface, polyetherketone, ethylene propylene rubber, etc. are heat resistant and water resistant. By using polymer pipes that are durable and oil resistant, even if the resin shrinks and cracks occur when the resin hardens, the cracks will continue to grow in the pipe, and if a cooling medium such as water or oil is later poured into the pipe. It is possible to prevent the cooling medium from flowing out through this crack.

In other words, by using a pipe that does not adhere to the resin, such as polytetrafluoroethylene, as the insulating pipe, even if a crack occurs in the resin, the crack will not penetrate the pipe and will propagate along the interface between the pipe and the resin. . Further, by using a double pipe, even if a crack occurs in the outer pipe, for example, a tube, the crack can be prevented from growing in the polymer pipe. Polytetrafluoroethylene is also made of polytetrafluoroethylene with glass or polyester monogamous fibers braided onto the surface.

By using heat-resistant, water-resistant, and oil-resistant polymer pipes such as polyetherketone and ethylene propylene rubber, stress is alleviated at the braided section.

It is possible to stop the growth of cracks that occur in the resin.

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

First, thin wires coated with an enamel film made of polyesterimide were twisted on the surface of electrolytic copper with a diameter of 50 tones to form rectangular twisted wires with a cross section of 4 m x 1'OI.

An insulated conductor 12 is obtained by applying a semi-cured prepreg insulating tape onto the glass tape by applying epoxy varnish to the glass tape. As shown in FIG. 4, this insulated conductor 12 is placed in a two-layer semi-cylindrical steel winding mold 14 having grooves 13 on its surface and polytetrafluoroethylene baked onto the surface and subjected to mold release treatment. Get involved.

At this time, the height of the rolled up insulated conductor should be slightly larger than the depth of the groove. On top of this, an insulating plate 15 made of a flexible epoxy glass sheet with a thickness of 0.5 m+ and coated with a semi-cured adhesive on one side is placed so that the adhesive faces the insulated conductor. Furthermore, from above this, a backing plate 16 that has undergone mold release treatment is applied to the surface of polytetrafluoroethylene, and while heating the entire surface, pressure is applied to the backing plate with a press, and prepreg insulation tape and semi-cured adhesive are applied. harden the agent. Next, the backing plate 16 is removed and the insulating plate 15 to which the insulated conductor 12 is bonded is taken out from the winding form 14, thereby obtaining a saddle-shaped coil bonded to the insulating plate as shown in FIG. An insulating plate to which an insulated conductor having a different shape is bonded is obtained by a similar method using a winding former having a different shape. In this way, 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.

Separately, prepare a cylindrical steel mandrel whose surface has been baked with polytetrafluoroethylene and subjected to mold release treatment.

A glass cloth sheet having a thickness of 0.13++e is wound around this surface 10 times under tension.

On top of this, three types of saddle-shaped coils are bonded to the insulating plate obtained above, and first, one each of the A coils is placed at symmetrical positions shifted by 180° on the circumference of the mandrel.

Next, an insulating pipe 4 made of polytetrafluoroethylene having an inner diameter of 61111 and an outer diameter of 7 mm is spirally wound from above. Next, place one B coil each on top of that in the same way.
The mandrels are arranged at symmetrical positions shifted by 80 degrees on the circumference of the mandrel, and furthermore, an insulating pipe made of polytetrafluoroethylene with an inner diameter of 6I and an outer diameter of 7- is wound spirally thereon. Furthermore, one each of the C coils is similarly arranged at symmetrical positions shifted by 18° on the circumference of the mandrel. A glass cloth sheet with a thickness of 0,] and 3 m is wound 10 times on top of this with tension applied.

Polytetrafluoroethylene is baked on the surface from the outside, and a mold that has been subjected to mold release treatment is attached and sealed. In addition,
Both ends of the insulating pipe are tightly plugged to prevent resin from entering the pipe during the subsequent impregnation process.

Next, the whole thing is carried into a vacuum container, and the cavity inside the mold is depressurized with a vacuum pump, resulting in a resin made of an epoxy resin composition.]
After feeding 7, pressure is applied to impregnate the resin. Thereafter, the resin was heated and cured.

After heating and curing is completed, the mold is removed and the mandrel is removed to obtain an electromagnetic coil as shown in cross-section in FIG.

In the above embodiment, stranded wires made of thin wires were used as the insulated conductor 12 in order to reduce eddy current loss.
This is to make it easier to wind a rectangular wire with a large cross-sectional area. The reason why the prepreg insulation tape is wrapped around the insulated conductor is that when it is heated and pressurized, the resin melts and hardens to bond the insulated conductor to the dirt floor and between the insulated conductor and the insulating plate 15 made of epoxy glass sheet. This is to make it happen. Furthermore, the reason why the prepreg insulating tape was rolled is to make it easier to wind it into the desired shape, and at the same time to secure an infiltration path for the resin to impregnate the voids in the stranded wire later.

The reason why the insulating pipe made of polytetrafluoroethylene was wound in a spiral shape was to cool the electromagnet by later flowing a cooling medium such as water or oil through the pipe. The reason for using insulating pipes is that metals induce eddy currents, which increases loss and at the same time deteriorates the accuracy of the magnetic field. Furthermore, polytetrafluoroethylene is used because it does not adhere to the impregnated resin, so that even if a crack occurs in the resin, the crack will not penetrate through the pipe but will grow along the interface between the pipe and the resin. In addition, after winding a glass cloth sheet on the surface of the mandrel and arranging three types of saddle-shaped coils adhered to the insulating plate obtained above, winding the glass cloth sheet from above is as follows. This is to fix the insulated conductor and insulate the conductor by later impregnating and curing the resin. The inside and outside of the coil are made of FRP18 made of glass cloth sheets and epoxy resin, creating a mechanically strong structure. Therefore, even if the mandrel is removed, it has sufficient mechanical strength to maintain an integral structure as an electromagnet.

The electromagnet is sufficiently cooled by flowing a cooling medium such as water or oil through the insulating pipe. Furthermore, since an insulating pipe is used, eddy currents are not induced and the accuracy of the magnetic field does not deteriorate. Furthermore, since polytetrafluoroethylene is used, it does not adhere to the impregnated resin, so even if a crack occurs in the resin, the crack will not penetrate the pipe and the cooling medium will not flow out.

Further, according to the above embodiment, since a groove is dug in the mold and the insulated conductor is wound into the groove, an electromagnet with high dimensional accuracy of the completed coil and high magnetic field accuracy can be produced. Furthermore, by preparing one winding form and one metal mold, a large number of coils can be made with the same precision without the complicated work of winding an insulated conductor while inserting an insulating spacer as in the conventional method.

Moreover, as already mentioned, a double pipe or a polymeric pipe whose surface is braided with insulating fibers can be used as the insulating pipe.

Further, as the resin to be impregnated, a resin alone may be used, or a resin containing a filler such as glass fiber, silica, alumina, etc., which does not easily cause cracks, may be used.

〔Effect of the invention〕

As explained above, according to the present invention, a wound flexible insulating pipe for flowing a cooling medium is placed in a mold near the shaft of a wound electrically insulated wire, and the inside of the pipe is removed. This is an electromagnetic coil that is integrated by injecting resin into the cavity and hardening it, so heat generation due to resistance loss in the conductor can be absorbed by passing a cooling medium such as water or oil through the pipe, even if it is a very thin wire. Alternatively, cooling can be easily achieved by using twisted wires as conductors. Also, since insulating pipes are used, there is no eddy current loss. Furthermore, since the electrically insulated wire shaft is fixed with resin, there is no fluctuation in the magnetic field, and an electromagnet with high dimensional accuracy and high magnetic field accuracy can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view for explaining one embodiment of the method for manufacturing an electromagnetic coil according to the present invention, FIG. 2 is a cross-sectional view of a double pipe which is an example of an insulating pipe used in the present invention, and FIG. The figure shows a polymer pipe made of braided fibers, which is an example of an insulating pipe used in the present invention, FIG. 4 is an explanatory diagram for explaining the process of bonding an insulated conductor to an insulating plate, and FIG. 5 shows an insulating plate. FIG. 6 is a sectional view of an electromagnet produced by the method of the present invention, and FIG. 7 is a sectional view of a hollow conductor conventionally used in forced cooling type coils. 1. Conductor, 2. Hollow part, 3. Electrically insulated wire shaft, 4. Insulating pipe, 5. Inside the pipe, 6.
··resin. 7...Cooling medium, 8...Double pipe, 9...
Polymer pipe, 10...Tube, 11...Insulating fiber, 12...Insulated conductor, 13...Groove. 14...Steel manufacturing winding form, 15...Insulating plate, 16...Plate, 17...Resin, 18...FRP agent consisting of glass cloth and epoxy resin Noriyuki Chika, Patent Attorney, Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (5)

[Claims] (1) After winding a flexible insulating pipe near the wound electric insulating wire ring, it is placed in a mold and resin is injected into the gap excluding the inside of the pipe, and then hardened. A method of manufacturing an electromagnetic coil characterized by integrating the coil. (2) The method for manufacturing an electromagnetic coil according to claim 1, wherein a pipe made of a material that does not adhere to resin is used as the insulating pipe. (3) The method for manufacturing an electromagnetic coil according to claim 1, characterized in that a pipe made of polytetrafluoroethylene is used as the insulating pipe. (4) The method for manufacturing an electromagnetic coil according to claim 1, characterized in that a double pipe made by stacking two pipes that are not bonded to each other is used as the insulating pipe. (5) The method for manufacturing an electromagnetic coil according to claim 1, wherein a pipe whose surface is reinforced with insulating fibers is used as the insulating pipe.