JPS58263Y2 - resin molded coil - Google Patents

Description

[Detailed description of the invention] The present invention provides a resin molded coil with excellent electrical characteristics and crack resistance. Specifically, the coil is provided with a resin molded coil inside the insulating layer of the coil over the entire Y circumference of the coil. By providing a void layer and absorbing uneven internal stress due to various structures occurring within the insulating layer, cracks (hereinafter referred to as cracks) occurring in the insulating resin layer are prevented, and at least one side of this void layer is provided with electric field relaxation. The object of the present invention is to provide an insulating coating for a resin-molded coil that alleviates the non-uniform electric field around the conductor and is free from the risk of partial discharge.

Figure 1 shows the appearance of a resin molded coil.
As shown in the figure, a resin mixed with a large amount of filler was cast into a coil 3 into a mold to form an insulating coating 4.

The purpose of mixing a large amount of filler into the resin in this way is to alleviate the internal stress caused by the difference in thermal expansion coefficient between the electric wire and the casting resin, and to prevent the occurrence of cracks. It was something.

In other words, the thermal expansion coefficients of both of the above are brought close to each other,
In the temperature range lower than the thermal deformation temperature of the resin, they are almost equal, but in the higher temperature range, the coefficient of thermal expansion of the resin increases rapidly, while the coefficient of thermal expansion of the metal remains unchanged, resulting in a large difference in the coil. Internal stress due to temperature changes becomes large and cracks tend to occur in the resin, making it extremely difficult to ensure long-term safety.

When a crack occurs, the insulating layer loses its insulating ability, resulting in dielectric breakdown and damage to the coil.

The present invention eliminates the above-mentioned drawbacks and provides a resin molded coil that can prevent cracks from occurring under any harsh conditions during equipment use and has a highly reliable insulation coating with excellent electrical properties. .

The present invention will be explained below with reference to FIG. 3 showing one embodiment thereof.

In the present invention, an insulating layer 6 is formed on the coil 5, an electric field relaxing layer I is formed integrally with the insulating layer 6 on top of the insulating layer 6, an electric field relaxing layer 9 is further provided through a gap layer 8, and a resin is further applied to this. The insulating layer 10 integrated with the electric field relaxation layer 9 is formed by casting, and the insulating coating 11 of the electromagnetic coil is formed.

The details of the present invention are shown below. The insulating layer 6 plays the following role.

When the electric field relaxation layer T, which will be described later, is formed directly on one of the coils, if the potential difference between the coil winding start a and the winding end b is large, the electric field relaxation layer T, that is, a layer with low resistance, will be larger than the small hole (pinhole) in the wire coating. An insulating layer 6 is formed to prevent short-circuiting through the conductive or semi-conductive layer, which may damage the coil.

However, if the wire coating is sufficiently reliable or
, b When the threshold voltages are low, there is no particular need to provide the insulating layer 6.

This also has a stress buffering effect, similar to a resin layer mixed with a large amount of filler.

Since this insulating layer 6 is a void layer 8 which will be described later, it is hardly subjected to internal stress and no cracks will occur.

Therefore, for this structure, an elastic body such as rubber may be used, resin mixed with a large amount of filler may be cast and dipped, or powdered resin mixed with a large amount of filler may be coated.

Furthermore, a strong resin layer containing high-strength short fibers such as glass fibers may be provided by dipping or the like.

The electric field relaxation layer I provided next to the insulating layer 60 relieves electric field concentration in the vicinity of the coil 5 and prevents the generation of partial discharge due to the void layer 8 on the outside thereof.

That is, the electric field relaxing layer 9 outside the electric field relaxing layer 7 and the gap layer 8
By setting them to the same potential, partial discharge in the void layer 80 is prevented.

Such an electric field relaxation layer 7.9 may be a resin containing a conductive substance such as carbon, a metal compound, or a metal, the above substance itself, or a semiconductive or conductive resin.

This electric field relaxation layer 7 is integrated with the above-mentioned insulating layer 6 and is heavy on the vehicle, so it may be mounted on the insulating layer 6, or it may be wound with carbon paper etc. into a coil and cast in resin. Moyo (・
.

As described above, if the dielectric strength of the insulated wire is sufficiently large, the electric field relaxation layer 7 may be formed directly on the coil.

For example, by using semiconductive rubber or the like, it is possible to have an electric field relaxation effect and a stress buffering effect at the same time.

The void layer 8 relieves the internal stress generated in the insulating layers 6 and 10, and prevents cracks from occurring in the insulating layers 6 and 10 even under severe conditions.

In other words, the internal stress due to the difference in thermal expansion coefficient between the metal coil and the resin insulating layer is large, and if the insulating layer is thick, it becomes extremely thick, causing cracks to occur in the resin layer, which has lower mechanical strength than metal. do.

Therefore, by forming the void layer 8 inside the insulating layer over the entire circumferential surface of the coil as in the present invention, the thickness of the insulating layer can be divided and the generated stress can be reduced. The void layer 8 can absorb the volume change caused by the insulating layers 6, 1
0 cracks do not occur.

The void layer 80 can be produced by forming the above-mentioned electric field relaxation layer T, and applying a releasable film thereon by baking or the like to bring the coil constituent layers 12 and 13 into a non-bonded state.

The electric field relaxation layer 9 is made to have the same potential as the electric field relaxation layer T as described above to prevent partial discharge in the gap layer 8.

The void layer 8 does not have constant gaps everywhere and is not chemically bonded, and the semiconductive layers 7 and 9 are in contact everywhere, and the amphibodiconductive layers are at the same potential. becomes.

Is it necessary if the void layer 8 is sufficiently small? , 9 are not necessary, and either one may be used; however, it is practically more reliable to provide the short electric field relaxation layers 7 and 9.

Since a non-uniform electric field can be made into a uniform electric field by the electric field relaxation layer enclosed in the housing, it is possible to suppress the occurrence of partial discharge in the void.

As the constituent material of the electric field relaxation layer 9, the same material as that of the electric field relaxation layer T can be used.

The insulating layer 10 is formed by the electric field relaxation layer 9 and is obtained by resin casting.

Due to the crack resistance properties of this casting resin, the resin mixed with a large amount of filler makes the car heavy.

As described above, this insulating layer 10 generates almost no internal stress due to the void layer 8, so no cracks occur.

As explained above, according to the present invention, since the void layer and the electric field relaxation layer are present in the insulating layer over the entire circumferential surface of the coil, the generation of internal stress can be greatly reduced and the generation of partial discharge can be reduced. It is possible to form an insulating coating for a coil with excellent crack resistance and electrical properties.

In addition, the void layer and the electric field relaxation layer are not manufactured in advance by combining several types of insulating materials and semiconducting materials and then inserted.
Since they are formed sequentially, it is easy to form them on the entire circumferential surface of the coil.

Furthermore, since the void layer is formed by baking a mold releasable film, it can be applied to complex shapes and does not interfere with resin molding, which is of great practical value.

[Brief explanation of drawings]

Fig. 1 is an external view of a resin molded coil, Fig. 2 is a cross-sectional view of the structure of a conventional electromagnetic coil taken along the line A-A' in Fig. 1, and Fig. 3 is a cross-sectional view taken along the line A-A' in Fig. 1. FIG. 2 is a cross-sectional view of the structure of the resin molded coil according to the invention. 5... Coil, 6, 10... Insulating layer,
7y9...Electric field relaxation layer, 8...Void layer, 11...Insulating coating.

Claims (1)

[Scope of utility model registration request] An electric field relaxation layer made of semiconductive resin is formed over the entire circumference of the winding inside the insulating layer of the resin molded coil, and a void layer is formed by baking a release film over the entire circumference. The resin molded coil is further characterized in that an electric field relaxation layer is formed over the entire circumferential surface.