JPH0412509A - Resin-molded coil - Google Patents

Abstract

PURPOSE:To eliminate a crack, and to easily manufacture an insulation spacer by employing the spacer by coating a cylinder woven with high strength fiber material with resin as the spacer for supporting an electromagnetic coil. CONSTITUTION:Insulation spacers 6 are inserted between block coils 2a and 2b, between block coils 2b and 2c and between the coils 2a-2c and a mold 9 to obtain intervals between the coils 2a-2c and between the coils 2a-2c and the mold 9. As such spacers 6, a cylinder obtained by weaving high strength fiber materials 7 is coated with resin 8. Thus, a crack of a resin-molded coil 1 is prevented, and the spacer 6 can be easily manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a resin molded coil formed by integrally molding a plurality of block coils with resin, for example.

(Prior Art) Conventional resin molded coils are often used in heavy electrical equipment such as molded transformers and molded transformers due to their excellent moisture resistance, dust resistance, and insulation properties. Resin molded coils used in molded transformers are broadly divided into cast type and impregnated type, and most of them are of the former cast type.

By the way, casting type resin molded coils generally use a mold, and the coils are housed in the mold, and the coils are kept at appropriate intervals, and epoxy resin or the like is applied between the gaps or between the coils. It is manufactured by injecting casting resin and curing it by heating. Here, when the coil is for high voltage use, it is divided into multiple block coils and electrically connected to form a single phase electromagnetic coil, which is made of gold. The method used is to store it in a mold and mold it with resin. In this case, an appropriate insulating spacer is required to maintain the distance between the block coils or between the mold and the coil, but depending on how the insulating spacer is handled, the insulating spacer and the casting resin may There were drawbacks such as peeling at the boundary between the resin and the resin, or cracks in the resin, causing dielectric breakdown.

A conventional resin molded coil will be explained with reference to FIG.

As shown in FIG. 5, the resin molded coil 1 is a block coil 2a in which a coil conductor 2 is continuously wound.

2b and 2C are stacked together via an insulating spacer 4a,
Furthermore, these block coils 2a, 2b and 2C
In order to uniformly cover the periphery of the block coils 2a, 2b, 2 when housed in a mold (not shown), the block coils 2a, 2b, 2
An insulating spacer 4b is also inserted between C and resin molded. In addition, 3a and 3b are block coils 2a and 2b.
, 2c is the lead-out terminal of the electromagnetic coil. The insulating spacers 4a and 4b are made of cubes with each side approximately 1 cm.
In order to minimize the occurrence of thermal stress caused by adhesion with the casting resin or the difference in linear expansion coefficient of the material, or peeling caused by this, a resin molded with the same resin as casting resin 5 and with a roughened surface is used. It will be done.

(Problem to be Solved by the Invention) In the resin molded coil 1 manufactured in this manner, the weakest points in terms of stress are the insulating spacers 4a,
This is the boundary between 4b and the casting resin 5. Even if surface roughening such as sanding is performed, the adhesive strength of this part is reduced to 40 to 60% of the tensile strength of a molded resin product.

As an example, we will show the results of an adhesive force test using a dumbbell piece when it was made from a single piece of resin and when it was made in combination with a spacer. The test method is shown in FIG. 6, and the results are shown in FIG. That is, in FIG. 6, a resin spacer 10 of about 1 cm square with a sanded surface is placed in a mold so as to be located at the center in the longitudinal direction, and then resin 11 is poured between the molds and hardened by heating. Dumbbell single-handed work 2
Create. When this dumbbell piece 12 was subjected to a tensile test using an autograph, most of the resin spacers IO and resin I
It breaks at the interface of I. In this case, although it varies depending on the cure state of the resin spacer IO, as shown in the test results in Figure 7, the adhesive strength of the combination product using the resin spacer 10 is 51% of that of the single resin product integrally molded with the same resin. It is declining.

As described above, the adhesive strength is weak at the boundary between the insulating spacers 4a and 4b, and if cracks (or peeling) occur, partial discharge may occur in this area, leading to a short circuit between the coils. Furthermore, if peeling or cracking occurs in the upper coil support insulating spacers 4a and 4b of the coil 2C, electric discharge occurs between the coil 2c and the iron core (not shown).
There is a risk of ground fault damage.

Furthermore, in the method of molding the insulating spacers 4a and 4b, a sheet is molded in advance from the same resin as the casting resin 5, cut into an appropriate size, and then processed into the required dimensions using a grinder or sandpaper, etc. It is necessary to roughen it,
There were drawbacks such as the fact that it took a long time to manufacture.

The present invention was made to eliminate the above-mentioned drawbacks, and its purpose is to eliminate peeling or cracking at the boundary between the coil supporting insulating spacer and the casting resin, improve quality and reliability, and improve the quality and reliability. The object of the present invention is to provide a resin molded coil that allows easy production of insulating spacers.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a resin molded coil in which an electromagnetic coil is molded with resin, in which a high-quality insulating spacer is used to support the electromagnetic coil. It is characterized by using an insulating spacer made of a cylindrical body knitted from a strong fiber material and coated with resin.

(Function) According to the resin molded coil of the present invention, since the insulating spacer has countless holes like a mesh, it is easily impregnated with the casting resin, and the interface between the insulating spacer and the casting resin disappears. to become one. Therefore, cracks and the like do not occur in the casting resin of the resin-molded coil.

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

FIG. 1 is a longitudinal cross-sectional view of one embodiment of the present invention, and FIG. 2 is a cross-sectional view taken from the direction ■--■ in FIG. 1.

1 and 2, reference numeral 6 denotes an insulating spacer manufactured by a method to be described later, and this insulating spacer 6 is located between block coils 2a and 2b,
and between the block coils 2a, 2b, 2c and the mold 9 to ensure the spacing between the block coils 2a, 2b, 2c and between the block coils 2a, 2b, 2c and the mold 9. are doing. Block coil 2 like this
a.

2b and 2c are set in the mold 9, a casting resin 5 such as epoxy is injected under vacuum pressure, cured by heating, and then the mold 9 is released to form the resin molded coil 21.
is obtained.

By the way, the insulating spacer 6 is shown in the perspective view of FIG.
It was molded as follows. First, the thickness is 50-5
A cylindrical body is formed by knitting glass fibers 7 of 0.05 μm. The gap between the meshes of the glass fibers 7 is selected based on the strength required by the spacer and the impregnability of the casting resin, and is generally 1 to 4 mm. A core metal (not shown) is inserted into the cylindrical body of the glass fiber 7 so as to have an appropriate thickness h, and the cylindrical body is formed into a rectangular cylindrical shape. The molding is carried out by dipping the core bar into an epoxy resin bath, coating the cylindrical body of glass fiber 7 with resin 8, and then heating and curing it. Thereafter, by removing the mandrel, a rectangular cylindrical insulating spacer 6 is obtained.

It is desirable to select a resin 8 that has good compatibility with the resin to be cast later, and it is better to use a resin with a high heat deformation temperature so that the strength can be kept constant at high temperatures.

In the resin molded coil 1 manufactured as described above, the casting resin 5 and the insulating spacer 6 are integrated so that the casting resin 5 easily enters the insulating spacer 6. especially,
Since the insulating spacer 6 has a mesh square tube shape, there is no continuous boundary between the insulating spacer and the casting resin 5 as in the past, and since the amount of glass fiber 7 used is small, the boundary area is also reduced. Become. Therefore, cracks and the like do not occur at the boundary between the casting resin 5 and the insulating spacer 6. Furthermore, since the glass fibers 7 constituting the insulating spacer 6 are pre-impregnated with the resin 8, even if the casting resin 5 has a high viscosity, there is no need to impregnate the thin gaps in the glass fibers 7, and no It has the characteristic that impregnated voids are difficult to form.

Furthermore, although it is not possible to obtain the compressive strength sufficient to withstand the weight of the coil 2 by using only the glass fiber 7 woven into a cylindrical shape, by coating the resin 8, it is possible to easily create an insulating spacer 6 having sufficient strength to support the coil. Obtainable.

In the above embodiment, the insulating spacer 6 is formed into a rectangular tube shape after knitting the glass fibers 7 into a mesh shape. Any cylindrical body may be used as long as it has the strength to ensure the following.

Furthermore, in the above embodiment, the insulation spacer 6 is arranged in the horizontal direction where the radial direction is compressed, but if it is arranged in the vertical direction where the axial direction is compressed as shown in FIG. Spacers can be configured. Furthermore, the present invention is not limited to an electromagnetic coil made up of a plurality of block coils, but can be implemented in a similar manner to a resin molded coil made up of a single electromagnetic coil.

[Effects of the Invention] As explained above, according to the resin molded coil of the present invention, since the insulating spacer has countless holes like a mesh, the casting resin easily impregnates the insulating spacer and the casting resin. The boundaries between the two become one, as if they have disappeared. Therefore, an excellent effect is achieved in that no cracks or the like occur in the resin molded coil.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a sectional view taken from the direction ■-■ in FIG. 1, FIG. 3 is a perspective view of the insulating spacer used in FIG. 1, and FIG. The figure is a sectional view of another embodiment of the present invention, FIG. 5 is a cross-sectional perspective view of the main part of a conventional resin molded coil, FIG. 6 is a perspective view of a dumbbell test piece, and FIG. 7 is the dumbbell test of FIG. 6. It is a characteristic diagram for explaining the characteristic of a piece. 1.21... Resin molded coil 2... Coil conductors 2a to 2c... Block coils 3a, 3b... Output terminals 4a, 4b, 6... Insulating spacer end... Casting resin 7...・Glass fiber 8...Resin 9...Mold

Claims (1)

[Claims] A resin molded coil formed by molding an electromagnetic coil with resin, characterized in that an insulating spacer formed by coating a cylindrical body woven from a high-strength fiber material with resin is used as an insulating spacer for supporting the electromagnetic coil. Resin molded coil.