JP2777238B2 - Manufacturing method of molded coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a method of winding a coil around an insulating layer formed on an outer peripheral portion of a bobbin, and then forming a coil on the outer peripheral portion of the coil and the insulating layer. The present invention relates to a method for manufacturing a molded coil for molding an insulating resin.

(Prior Art) A conventional method of manufacturing a molded coil for a dry transformer, for example, will be described with reference to FIG. That is, a semi-cured prepreg base material is wound around the outer periphery of the bobbin 1 to form the insulating layer 2, and the block coils 3 a to 3 c constituting the coil 3 are spaced around the outer periphery of the insulating layer 2 at intervals. Roll. Then, the outer peripheral mold 4 and the both end face molds 5, 5 are assembled, and an insulating resin 6 is injected into the inner mold and heat-cured to produce a molded coil 7.

(Problems to be solved by the invention) However, the above-described manufacturing method has the following problems.

(1) When the coil 3 is wound around the outer periphery of the insulating layer 2, there is no reference for determining the position, and therefore, it is difficult to position the coil 3.

(2) Since the adhesiveness between the pre-leg base material forming the insulating layer 2 and the insulating resin 6 is not good, an internal stress is generated when the insulating resin 6 cures and contracts or a temperature change occurs.
In particular, since a portion corresponding to the inner circumferential angle of the coil 3 is subjected to stress concentration, the insulating resin 6 is peeled or cracked from this point as a starting point, and the insulation strength and mechanical strength are reduced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of manufacturing a molded coil that can easily position a coil and prevent a decrease in insulation strength and mechanical strength.

[Structure of the Invention] (Means for Solving the Problems) In the method for manufacturing a molded coil of the present invention, a semi-cured prepreg base material is wound around an outer peripheral portion of a bobbin to form an insulating layer. A plurality of coil forming portions having a concave shape are formed, and a block coil is wound around each of the plurality of coil forming portions to form a coil, and then the insulating layer is heated and cured, and the insulating layer and the coil are formed. It is characterized in that an insulating resin is molded on the outer periphery.

(Operation) According to the method of manufacturing a molded coil of the present invention, the coil is configured by winding the block coil around each of the plurality of concave coil forming portions on which the insulating layer is formed, so that the coil can be easily positioned. Moreover, since the inner peripheral corner of the coil is located inside the insulating layer from the boundary surface with the insulating resin, peeling and cracking do not occur.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

An insulating layer 12 is formed by winding a semi-cured prepreg base material around an outer peripheral portion of a winding frame 11 that is also used for an inner peripheral die. The coil forming portion 13 is formed in a concave shape by pressure-forming a plurality of portions on the outer peripheral portion of the insulating layer 12, for example, three portions at predetermined intervals with a roller or the like. The block coils 14 a to 14 c constituting the coil 14 are sequentially wound around the coil forming unit 13. In this state, the whole is heated and dried to cure the prepreg base material of the insulating layer 12 (see FIG. 2). Next, the reel 11
An outer mold 15 is arranged on the outer periphery of the coil 14, and end face molds 16, 16 are arranged on both ends of the winding frame 11 and the outer mold 15. And
An insulating resin 17 is injected into the outer peripheral portion of the coil 14 from an injection port (not shown) and is cured by heating, thereby manufacturing a mold coil 18 for a dry transformer (see FIG. 3).

According to the above embodiment, the following effects can be obtained. That is, the coil forming portion 13 is formed on the insulating layer 12, and the coil forming portion 13 is formed.
Since the block coils 14a to 14c of the coil 14 are wound around the coil 14, the positioning of the coil 14 is facilitated and the coil winding operation is simplified. In this case, the block coils 14a-1
Since the coil 4c is wound around the coil forming portion 13, the block coils 14a to 14c are not displaced in the axial direction, and therefore, between the block coils 14a to 14c or between the block coils 14c to 14c.
Can be kept as specified, and the required insulation distance can be obtained. Further, since the coil forming portion 13 is formed in a concave shape, the inner peripheral corner 14d of the coil 14 is located inside the insulating layer 12 so as to be surrounded by the insulating layer 12 with respect to the boundary surface with the insulating resin 17, and accordingly, 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. The difference from the above embodiment is that a narrow prepreg base material 19 is wound around a plurality of locations on the outer peripheral portion of the insulating layer 12, and these prepreg base materials 19 are formed. Further, the concave portion formed by the insulating layer 12 is the coil forming portion 20, and this embodiment also has the same effect as the above embodiment.

[Effects of the Invention] The method of manufacturing a molded coil of the present invention includes forming a plurality of concave coil forming portions in an insulating layer made of a prepreg base material at an outer peripheral portion of a winding frame, and forming the plurality of coil forming portions. The coil is configured by winding a block coil on each side, so coil positioning is easy, coil winding work is simple, no peeling or cracks occur in the insulating resin, insulation strength and mechanical strength This has the effect of preventing a reduction in strength.

[Brief description of the drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a view of a mold assembled and partially cut away, FIG. 2 is a sectional view showing a manufacturing process, and FIG. FIG. 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 bobbin, 12 is an insulating layer, 13 is a coil forming part, 14 is a coil, 14a to 14c are block coils, 17 is an insulating resin, 18
Indicates a molded coil, and 20 indicates a coil forming portion.

Claims (1)

(57) [Claims] A semi-cured prepreg base material is wound around an outer periphery of a bobbin to form an insulating layer, and a plurality of concave coil forming portions are formed in the insulating layer. A method of manufacturing a molded coil, comprising: forming a coil by winding a block coil around a coil forming portion; heating and curing the insulating layer; and molding an insulating resin around the insulating layer and the outer periphery of the coil.