JPH03214614A - Manufacturing method of molded coil - Google Patents

Abstract

PURPOSE:To shorten the manufacturing time and to reduce a resin amount to be used by a method wherein a filler is filled into the gap at a coil and a final molding resin is filled. CONSTITUTION:A filler 22 is filled from the upper-part edge of a coil element 15; after that, molding resins 19, 20 are filled. Consequently, the gap part of the coil element 15 and the like is not filled with and is not impregnated with the molding resins 19, 20. The molding resins 19, 20 are impregnated with the filler 20 filled into the gap part of the coil element 15 and the like only at microscopic parts coming into contact with the molding resins 19, 20. As a result, a drop at the upper-part edge which is caused when the molding resins 19, 20 are hardened after their filling is hardly caused. Thereby, the manufacturing time can be shortened, and a molding resin amount to be filled can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a molded coil used in a molded transformer for power distribution and the like.

Conventional molded coils, which are formed by forming a resin layer such as epoxy resin around a bare coil, have characteristics such as excellent insulation and ease of maintenance, and are increasingly being used.

The conventional manufacturing method of molded coils, especially molded coils used for low voltage applications, involves disposing a sheet-shaped insulating material that also serves as a part of the mold on the inner and outer peripheries of an elementary coil. After filling and hardening the mold resin between the inner and outer circumferential parts with the upper end face facing downward and the lower end face facing upward, which has the rising lead part from this bare coil, the upper end face is turned upward. A common method is resin molding.

FIG. 4 shows a molded coil manufactured by a conventional method, FIG. 5 is a sectional view taken along the line V-V in FIG. 4, and FIG. 6 is a partially enlarged sectional view of FIG. 5. In these FIGS. 4 to 6, 1 and 2 are rising lead parts, which are made of an aluminum plate or a copper plate. 3 is a coil body, and 4 is an inner peripheral material made of a sheet-like insulating material disposed on the inner periphery of the coil body 3, and the material is a single piece of epoxy resin-impregnated glass cloth or a polyethylene terephthalate film pasted together. etc. are used.

Reference numeral 5 denotes an elementary coil, which is composed of conductive conductors 6 and interlayer insulating material 7 stacked alternately. Reference numeral 8 denotes an outer peripheral member made of a sheet-like insulating material disposed around the outer peripheral portion of the coil body 3, and the material is the same as that of the inner peripheral member 4. 9 is a molding resin injected between the raw coil 5 and the inner peripheral material 4 and outer peripheral material 8 and on the upper end surface of the raw coil 5; 10 is the mold resin injected into the raw coil 5;
The mold resin is injected into the bottom end surface of the The mold resin 10 is normally filled before the mold resin 9 to form a part corresponding to the mold resin mold on the outer periphery of the elementary coil 5, and then the resin is injected from the upper end surface to form the resin mold 1.' form 9. The upper end surface of the resin mold 9,
It is formed on the same plane as the inner circumference material 4 and the outer circumference tA8.

Problems to be Solved by the Invention However, in such a conventional molded coil manufacturing method, the upper end surface deteriorates due to the impregnation of the molded resin 9 injected from the upper end/face of the elemental coil 5 into the elemental coil 5 and curing shrinkage. Therefore, the injection of the molding resin 9 must be repeated several times, resulting in the problem of requiring extra time and molding resin.

The present invention solves these conventional problems, and aims to provide an excellent molded coil manufacturing method that can shorten manufacturing time and reduce the amount of resin used. do.

Means for Solving the Problems In order to achieve the above object, the present invention arranges a raw coil in which conductors and glabella insulating materials are alternately wound between an inner circumferential material and an outer circumferential material made of sheet-like insulating material. After setting the bottom end face up and sealing the bottom end face, mold resin is injected between the inner circumferential material and the outer circumferential material, and the bottom surface is molded with excellent mold releasability against the mold resin. Then, turn the bottom end face downward and fill the space between the inner and outer circumferential materials from the upper end face of the raw coil with the filler material, and then heat it to mold the resin on the bottom end face. The method includes the steps of curing the resin, and then filling and curing the upper end surface with a molding resin.

Therefore, according to the present invention, since the mold resin is filled after the filler is filled from the upper end surface of the base coil, the mold resin is hardly filled or impregnated into the voids of the base coil, etc. The impregnation of the mold resin into the filler filled into the voids of the bare coil etc. is carried out only in the minute parts that are in contact with the mold resin, so there is almost no deterioration of the upper end surface due to the hardening of the mold resin after filling, and the manufacturing process is improved. This has the advantage that the time is shortened and the amount of molding resin to be filled can be reduced.

5 Example FIG. 1 is a perspective view of a molded coil manufactured by the molded coil manufacturing method of the present invention, and FIG.
3 is a partially enlarged sectional view of FIG. 2. In FIGS. 1 to 3, 11 and 12 are rising lead portions, which are made of an aluminum plate or a body plate.

13 is a coil main body part, 14 is an inner peripheral material made of a sheet-shaped insulating material disposed on the inner peripheral part of the coil main body part 13,
As the material, epoxy resin-impregnated glass cloth alone or a polyethylene terephthalate film laminated together can be used. 15 is an elementary coil, which is composed of conductors 16 and interlayer insulating material 17 stacked alternately.

Reference numeral 18 denotes an outer circumferential member made of a sheet 1-shaped insulating material disposed on the outer circumference of the coil main body 3, and the material is the same as that of the inner circumferential member 14. 19 is a molding resin injected between the raw coil 15 and the inner peripheral material 14 and the outer peripheral material 18 and on the upper end surface of the raw coil 15; 20 is a molding resin injected into the bottom end surface of the raw coil 15.

Reference numeral 6 21 is a mesh for preventing the mold resin 20 from leaking through the base coil 15 when mold resin is injected into the bottom end face. 22 is a filler filled from the upper end surface of the raw coil 15.

Next, a method of manufacturing this molded coil will be explained.

First, after attaching the inner peripheral material 14 made of sheet-like insulating material to the winding core (not shown), the rising lead part 12 attached by welding or the like to the beginning of the winding is fixed, and the conductor 16 and interlayer insulating material 17 are alternately attached. After winding both of them a specified number of times, another rising lead part 11 is attached to the end of the last conductor 16.
Attach and secure. Then, an outer circumferential member 18 made of a sheet-like insulating material is attached to the outer periphery. These inner peripheral materials 1
4 and the peripheral material 18 preferably have some degree of rigidity, for example, B-stage epoxy resin impregnated glass cloth with a thickness of 0.2 mm to 0.25 mm.
It is preferable to use polyethylene terephthalate film (PET film) laminated together.

Next, in this way, the inner peripheral material 14 and the outer peripheral material 1 are placed on both sides.
8 with its bottom end face facing upward, and place crow wool, polyester wool, etc. on the bottom end face.
After covering with a mesh 21 made of ceramic wool or the like, a molding resin 20 (epoxy resin containing 60 to 70% by weight of inorganic filler) is injected. Next, this bottom end surface is covered with a lid member 23 whose surface in contact with the mold resin is made of a releasable material, and this time, with the bottom end surface facing downward and the top end surface facing upward, the inner peripheral material is covered from the top end surface. After filling the gap between the coil interlayer resin and the like between the coil 14 and the outer peripheral material 18 with the filler 22, heating is performed to harden the bottom mold resin 20, and then the mold resin 19 is filled from the upper end surface of the coil and hardened. .

As for the filler 22 that is filled from the upper end surface, the filling effect can be seen even with an inorganic substance such as silicon oxide, but in order to improve the mechanical properties of the coil interlayer resin, it is necessary to mix an inorganic powder with a binder such as a resin. one is more suitable. However, when mixing powders that cause volume changes such as resins, the mixing ratio becomes a problem, and in order to provide adhesiveness, it is necessary to increase the amount of resin, so determining the optimal mixing ratio is necessary. becomes important. The following table shows an example of the comparative study results of the blending ratios.

Composition ratio (wt%) Sample Epoxy powder Silica powder Outside I Adhesion Overall evaluation 1 0
100 Good None
Δ2 10
90 Good Small
△3 20
80 Good Good 4
30
70 Good Good 5
40 60
Good Good 6 50
50 Question part elementary school
Δ760401 part small good Δ870301
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Department Good ×10
90 10 Large recess Good × As is clear from this table, the ratio of epoxy powder to silica powder is 20 to 40
A weight percent range of 60 to 80 weight percent gives the best results. Here, silica powder is used as the inorganic powder9, but it is not limited to this, and any insulating inorganic powder such as alumina powder or magnesium oxide powder may be used for practical purposes. It is something that

Effects of the Invention As described above, according to the molded coil manufacturing method of the present invention, the final molding resin is filled after the filler is filled into the gap between the coils, so that the impregnation of the molding resin into the coil gap is almost non-existent. This eliminates the drop in the resin surface after filling with mold resin, thus reducing the number of injections of mold resin, shortening manufacturing time and reducing the amount of resin used, which significantly improves workability in mold coil manufacturing. effective.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a molded coil manufactured by the molded coil manufacturing method of the present invention, and FIG. 3 is a partially enlarged sectional view of FIG. 2, FIG. 4 is a perspective view of a molded coil showing an example of a molded coil manufactured by a conventional molded coil manufacturing method, and FIG. FIG. 4 is a sectional view taken along the line V-V, and FIG. 6 is a partially enlarged sectional view of FIG. 5. DESCRIPTION OF SYMBOLS 11, 12... Standing lead part, 12... Coil main body part, 14... Inner peripheral material, 15... Raw coil, 1
6... Conductor, 17... Interlayer resin, 18... Peripheral material, 19, 20... Mold resin, 21... Eyeliner,
22... Filling material, 23... Lid member.

Claims (2)

[Claims] (1) An elementary coil in which a conductor and an interlayer insulating material are alternately wound is arranged between an inner peripheral material and an outer peripheral material made of sheet-shaped insulating material, and the bottom end surface of the elementary coil is turned upward. After sealing, mold resin is injected between the inner circumferential material and the outer circumferential material, and the bottom surface of the bottom part is covered with a lid member having excellent mold releasability against the mold resin. After filling a filler between the inner circumferential material and the outer circumferential material from the upper end surface of the element coil with the bottom end surface facing downward, heating is performed to harden the molding resin on the bottom end surface, and then the filler is applied to the upper end surface. A method for manufacturing a molded coil, including a step of filling and curing mold resin. (2) Claim (1) wherein the filler to be filled from the upper end surface of the bare coil is a mixture of 20 to 40 weight % of B-stage epoxy powder resin and 60 to 80 weight % of inorganic powder.
A method of manufacturing the molded coil described.