JPH0464204A - Resin molded coil and manufacture thereof - Google Patents

Abstract

PURPOSE:To form a duct easily by forming a hollow duct lined with an insulating material between the conductor layer and conductor layer of a resin molded coil. CONSTITUTION:A prepreg insulator 2, in which a glass fibrous sheet insulator impregnated previously with a resin and brought to a semirigid state, is wound previously on the outer circumference of a foam 1 only by a section corresponding to coil height. A plurality of the foams 1 and the insulators 2 are disposed and interposed between windings 3-3', and winding conductors are wound. A molding resin 4 is injected extending over the whole coil, and heated and cured. Since the resin is heated and cured and a solvent such as trichlene is injected to the sections of the foams 1, the foams 1 are melted and removed and change into cavities, thus forming cooling ducts 6. The insulators 2 are wound only by sections corresponding to coil height for preventing direct contacts with the winding conductors 3, 3' or an inter-layer insulator of the solvent when the solvent is injected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a resin molded coil, and particularly to a resin molded coil provided with a cooling duct having a complicated cross-sectional shape, and a method for manufacturing the same.

[Prior art] Conventional resin molded coils with cooling ducts are manufactured by placing and interposing a duct mold that fits the shape of the duct between the conductor layers when winding the wire-wound conductor layers, injecting the molding resin and heating and hardening it. , is formed by pulling out the duct mold.

In addition, when high and low voltage coils are integrated with molded resin, the entire mold is finished with an insulator between the high voltage side conductor and the low voltage side conductor, but a duct mold is used in the same way as in the above case. After winding the conductor, injecting molding resin and hardening, the duct mold is pulled out to form a duct between the high and low voltage conductors and integrate them. As a method for manufacturing this type of tubular coil, there is an invention disclosed in Japanese Patent Publication No. 54-5499.

[Problems to be Solved by the Invention] The above-mentioned prior art uses duct molds to form ducts between winding conductor layers or between high-voltage and low-voltage conductors, so there are differences in specifications (for example, capacity). Various types of duct molds must be prepared depending on the shape of the coil, and the molds lack versatility. Moreover, in order to punch out the duct mold after heating and hardening the mold resin, high accuracy is required in the surface finish of the mold and the dimensions of the punching taper, and a special hydraulic system may be required, which increases costs. This was a factor in the increase.

The present invention has been made in view of the above circumstances, and it is possible to form a cooling duct with a complicated shape and a duct having cooling fins on the inner wall of a resin molded coil without using a duct mold, thereby reducing the cost. The purpose of the present invention is to provide an effective resin molded coil and a method for manufacturing the same.

[Means for Solving the Problems] The above purpose is to provide a first step of forming an inner conductor layer in which a conductor winding is wound in layers, and a layer having the same height as the height of the conductor layer on the outside of the conductor layer. and a second step of disposing a resin foam for duct molding covered with a prepreg insulating sheet material;
A third step of forming an outer conductor layer in which a conductor winding is wound in layers on the outside of the resin foam, and a fourth step of injecting a molding resin between the inner conductor layer and the outer conductor layer and curing it by heating. and a fifth step of dissolving the resin foam by injecting a solvent to form a hollow duct, and a resin molded coil manufactured by the manufacturing method.

[Effect]

With the above configuration, without using a duct mold,
A resin molded coil having a cooling duct having a complicated cross-sectional shape and a cooling duct with cooling fins inside the coil can also be easily formed.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a perspective view of an example of a resin foam for duct molding (hereinafter abbreviated as foam) used for the resin molded coil of the present invention, and FIG. Figure 3 is a perspective view showing a state in which the foam is inserted, and Figure 3 is a perspective view including a longitudinal section of the resin molded coil 5 forming the cooling duct of the present invention.

In FIG. 1, numeral 1 is a foam made of a resin material such as styrene or urethane. Around the outer periphery of the foam 1, a prepreg insulator 2, which is a semi-cured thin glass fiber insulator impregnated with a resin in advance, is wound by an amount corresponding to the height of the coil. As shown in FIG. 2, a plurality of foams 1 and prepreg insulators 2 are interposed between the windings 3 to 3' layers, and the winding conductor is wound with a zero-order molding resin 4 over the entire coil. Pour it over the entire area and heat it to harden. FIG. 2 is a diagram showing the state after the mold resin has hardened. After heating and hardening, by injecting a solvent such as trichlene into the foam 1, the foam 1 is dissolved and removed to form a cavity, thereby forming the cooling duct 6 shown in FIG. 3.

The reason why the prepreg insulator 2 is wound by the coil height equivalent to the height of the coil shown in Fig. 1 is that when the solvent is injected, the solvent flows into the winding conductor 3.
．． 3' or interlayer insulation (not shown), and in the absence of the prepreg insulation 2, the winding conductor is 3.3' or the interlayer insulating material comes into direct contact with the air, resulting in moisture absorption and dust adhesion, which impairs the moisture resistance and dust resistance of the resin molded coil 5. The prepreg insulator 2 is essential to obtain the above-mentioned effects.

Although not shown as another example, in FIGS. 2 and 3, the foam l is used as the inner winding conductor (generally the low voltage side winding).
After arranging a plurality of pieces on top, the outer winding conductor (generally the high voltage side winding) is wound, molding resin 4 is injected, and after heating and curing, the same solvent as in the previous example is injected.
The foam 1 is melted and removed to form a cooling duct, and a resin molded coil 5 with integrated high and low voltage conductors can be obtained through this cooling duct.

Other embodiments of the invention are shown in FIGS. 4-6.

A foam 7 made of styrene or urethane and pre-molded with an uneven or corrugated surface as shown in FIG. 4 is used, and is wound around the outer periphery of a winding mold 8 as shown in FIG. Further, a prepreg insulator 2 and a winding conductor 3 are wound around the outer periphery of the foam 7, a mold resin 4 is injected, and the resin molded coil 5 is formed by heating and curing. Next, if a solvent is injected into the foam 7 part and removed, the sixth
As shown in the figure, cooling fins 9 are formed on the inner wall surface of the coil. The presence of the cooling fins 9 increases the heat dissipation surface area and forms a cooling duct with a greater cooling effect.

7 to 9 are perspective views showing still other embodiments of the present invention. Foam 10.11.1 shown in Figures 7-9
No. 2 is suitable for forming a cooling duct having a complicated shape, taking full advantage of its solubility in solvents. For example, Figure 7 shows a foam 1 for obtaining a cooling duct with a small cross-sectional area at both ends of the coil and a large cross-sectional area near the center of the coil.
FIG. 8 and FIG. 9 show a foam body 11.12 for obtaining a cooling duct in which the cross-sectional area is small at the lower end of the coil and becomes larger toward the upper end of the coil. FIG. In the actual coil, the temperature of the inner winding at the bottom end of the coil is low, and the temperature of the winding at the top end of the coil is high.
Resin molded coil 5 formed according to FIGS. 8 and 9
The cooling duct is constructed so that a larger heat dissipation effect can be obtained successively toward the upper end of the coil. It is clearly difficult to mold the resin molded coil 5 having a cooling duct having a male shape shown in FIGS. 7 to 9 using a conventional mold. In other words, the structure and manufacturing method of the cooling duct shown in the above embodiments utilize the properties of solvent-soluble resin foam, and are suitable for cooling ducts with cross-sectional shapes that are difficult to form using conventional molds. It is also extremely easy to form.

〔Effect of the invention〕

By implementing the present invention, a cooling duct having a complicated cross-sectional shape and a duct having cooling fins on the inner wall of the resin molded coil can be formed without using a molding die, compared to the conventional cooling duct forming method for a resin molded coil. It is possible to provide a resin molded coil and a method for manufacturing the same that are extremely effective in reducing costs.

[Brief explanation of drawings]

Fig. 1 is a perspective view of one embodiment of the foam used for the resin molded coil of the present invention, and Fig. 2 is a perspective view of the foam shown in Fig. 1 inserted between conductor layers. 3 is a perspective view including a vertical section of a resin molded coil in which a cooling duct is formed by melting the foam shown in FIG. 2, FIG. 4 is a perspective view of another embodiment of the foam of the present invention, and FIG. The figure is a perspective view of the resin molded coil with the foam shown in Figure 4 inserted, Figure 6 is a vertical sectional view showing cooling fins on the inner wall of the coil obtained by melting the foam shown in Figure 5, and Figure 7 is a perspective view of the resin molded coil with the foam shown in Figure 4 inserted. 8 and 9 are perspective views showing the foam structure of still another embodiment of the present invention. 1.7.10.11.12...Foam 2.2'...
Prepreg insulator 3.3'...Wound conductor 4...Mold resin 5.
... Resin molded coil 6 ... Cooling duct 8 ... Winding mold 9 ...
cooling fins

Claims (3)

[Claims] 1. In a resin molded coil formed by injecting and curing a molding resin between conductor layers in which conductor windings are wound in layers, a hollow duct lined with an insulating material is formed between the conductor layers. Characteristic resin molded coil. 2. The resin molded coil according to claim 1, wherein the hollow duct has an irregularly shaped cross section or a different cross section depending on the height position. 3. A first step of forming an inner conductor layer in which a conductor winding is wound in layers, and a molding resin foam having approximately the same dimensions as the height of the conductor layer and covered with an insulating material on the outside of the conductor layer. a second step of arranging a conductor, a third step of forming an outer conductor layer having a conductor winding wound around the resin foam on the outside of the resin foam, and a step of forming an outer conductor layer between the inner conductor layer and the outer conductor layer; A method for manufacturing a resin molded coil, comprising a fourth step of injecting a molding resin and heating and curing it, and a fifth step of dissolving the resin foam by injecting a solvent to form a hollow duct.