JPH03183109A - Manufacture of molded coil - Google Patents

Abstract

PURPOSE:To make a coil positioning operation and a coil winding operation easy by a method wherein a coil is wound on a U-shaped coil formation part which has been formed in an insulating layer made of a prepreg base material at the outer circumference of a bobbin. CONSTITUTION:A prepreg base material in a semihardened state is wound on the outer circumference part of a bobbin 11 which is used also as an inner circumference mold; an insulating layer 12 is formed. Coil formation parts 13 are formed to be U-shaped in such a way that a plurality of parts, e.g. three parts at prescribed intervals, at the outer circumference part of the insulating layer 12 are pressurized and molded by using a roller or the like. Block coils 14a to 14c which constitute a coil 14 are wound sequentially on the coil formation parts 13. This whole assembly is heated and dried in this state; the prepreg base material for the insulating layer 12 is hardened. Then an outer circumference form 15 and edge face forms 16, 16 are installed, and an insulating resin 17 is injected into the outer circumference part of the coil 14; it is heated and hardened; a molded coil 18 for dry-type transformer use is manufactured.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a method for winding a coil around an insulating layer formed on the outer periphery of a winding frame, and then winding the coil around the outer periphery of the coil and the insulating layer. The present invention relates to a method of manufacturing a molded coil by molding insulating resin.

(Prior Art) A conventional method of manufacturing a molded coil for, for example, a dry type transformer will be described with reference to FIG. That is, a semi-cured prepreg base material is wound around the outer periphery of a winding frame 1 to form an insulating layer 2, and block coils 3a to 3C constituting the coil 3 are arranged at intervals around the outer periphery of this insulating layer 2. and wind it. and,
The outer mold 4 and both end molds 5 and 5 are assembled, and an insulating resin 6 is injected inside and hardened by heating to produce a molded coil 7.

(3W!IJ to be solved by the invention) However, the above manufacturing method has the following problems.

(1) When winding the coil 3 around the outer periphery of the insulating layer 2, it is difficult to position the coil 3 because there is no standard for determining its position.

(2) Prepreg base material forming insulating layer 2 and insulating resin 6
Since the adhesiveness between the insulating resin 6 and the insulating resin 6 is not good, internal stress is generated when the insulating resin 6 cures and contracts or when a temperature change occurs. Particularly, since stress concentration occurs in the inner peripheral corners of the coil 3, peeling and cracking occur in the insulating resin 6 starting from these points, resulting in a decrease in insulating strength and mechanical strength.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a molded coil that allows easy positioning of the coil and prevents a decrease in insulation strength and mechanical strength.

[Structure of the Invention] (Means for Solving the Problems) The method for manufacturing a molded coil of the present invention includes forming an insulating layer by winding a semi-cured prepreg base material around the outer periphery of a winding frame. The method is characterized in that a concave coil forming part is formed, a coil is wound around this coil forming part, the insulating layer is heated and hardened, and an insulating resin is molded around the insulating layer and the outer periphery of the coil.

(Function) According to the molded coil manufacturing method of the present invention, since the coil is wound around a plurality of concave coil forming portions formed with insulating layers, positioning of the coil becomes easy. Moreover, since the inner circumferential corner of the coil is located inside the insulating layer rather than the interface with the insulating resin, peeling and cracking do not occur.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

An insulating layer 12 is formed by winding a semi-cured prepreg base material around the outer periphery of the winding frame 11 which also serves as an inner periphery type. The coil forming portion 13 is formed into a concave shape by pressing a plurality of locations, for example, three locations at a predetermined interval, on the outer circumferential portion of the insulating layer 12 with a roller or the like. Block coils 14a to 14c constituting the coil 14 are sequentially wound around the coil-shaped bottom portion 13. In this state, the whole is heated and dried to harden the prepreg base material of the insulating layer 12 (m2
(see figure). Next, an outer peripheral mold 15 is arranged around the outer periphery of the winding frame 11 and the coil 14, and end walls 16 and 16 are arranged at both ends of the winding frame 11 and the outer J4 mold 15. Then, insulating resin 17 is injected into the outer periphery of the coil 14 through an injection port (not shown) and cured by heating, thereby producing a molded coil 18 for a dry type transformer (see FIG. 3).

According to the above embodiment, the following effects are achieved. That is, since the coil forming part 13 is formed on the insulating layer 12 and the block coils 14a to 14c of the coil 14 are wound around this coil forming part 13, the positioning of the coil 14 is facilitated, and the coil winding work is simplified. It gets easier. In this case, since the block coils 14a to 14c are wound around the coil forming portion 13, the block coils 14a to 14c do not shift in the axial direction.
The distance between the block coils 14c or below the block coils 14c can be maintained as specified, and the necessary insulation distance can be obtained. Furthermore, since the coil forming portion 13 is formed in a concave shape, the inner circumferential corner portion 14d of the coil 14 is located inside the insulating layer 12 so as to be surrounded by the insulating resin 17 rather than the boundary surface with the insulating resin 17. No peeling or cracking occurs in the insulating resin 17, and a decrease in insulation strength and mechanical strength can be prevented.

FIG. 4 shows another embodiment of the present invention, which differs from the above embodiment in that narrow prepreg base materials 19 are wound around multiple locations on the outer periphery of the insulating layer 12.
The four parts formed by the insulating layer 12 and the insulating layer 12 are used as the coil forming part 20, and this embodiment also provides the same effects as the previous embodiment.

[Effects of the Invention] The method for manufacturing a molded coil of the present invention includes forming a concave coil forming portion in an insulating layer made of a prepreg base material on the outer periphery of a winding frame, and winding a coil around this coil forming portion. Therefore, the positioning of the coil becomes easier, the coil winding work becomes easier, the insulating resin does not peel or crack, and a decrease in insulating strength and mechanical strength can be prevented.

[Brief explanation of drawings]

Figures 1 to 3 show one embodiment of the present invention, with Figure 1 being a partially cutaway view of the assembled state, Figure 2 being a sectional view showing the manufacturing process, and Figure 3 being a cross-sectional view showing the manufacturing process. 4 is a sectional view of a molded coil, FIG. 4 is a view corresponding to FIG. 1 showing another embodiment of the present invention, and FIG. 5 is a view corresponding to FIG. 1 in a conventional example. In the figure, 11 is a winding frame, 12 is an insulating layer, 13 is a coil forming part, 14 is a coil, 14a to 14c are block coils, 1
7 is an insulating resin, 18 is a molded coil, and 20 is a coil forming part.

Claims (1)

[Claims] 1. A semi-hardened prepreg base material is wound around the outer periphery of the winding frame to form an insulating layer, a concave coil forming part is formed in this insulating layer, and a coil is wound around this coil forming part, and then the insulating layer is A method for manufacturing a molded coil, comprising heating and curing the insulating layer and molding an insulating resin on the outer periphery of the coil.