JPH08264347A - Resin molded coil and method for forming surface conductive layer thereof - Google Patents

Abstract

(57) [Summary] [Object] To obtain a uniform surface conductive layer having an appropriate conductivity and having a surface conductive layer, and to improve crack resistance and partial discharge resistance. [Structure] The winding 3 around which the conductor 2 is wound is molded with a resin molding layer 4 made of an insulating resin. On the surface of the resin mold layer 4, a surface conductive layer 5 functioning as an outer ground layer.
To provide. The surface conductive layer 5 is composed of a solvent-soluble conductive polymer. The surface conductive layer 5 is formed by applying a solution of a conductive polymer in an appropriate solvent to the surface of the resin mold layer 4, and at this time, the concentration of the conductive polymer in the solution and impurities added The thickness and conductivity of the surface conductive layer 5 to be formed are adjusted to the optimum ones corresponding to the interlinkage magnetic flux density by adjusting the concentration, the number of coatings, and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded coil used in an induction device such as a transformer and having a winding formed by winding a conductor molded with an insulating resin, and a method for forming a surface conductive layer thereof. It is a thing.

[0002]

2. Description of the Related Art For example, in power receiving and distributing equipment, an outer layer grounding transformer provided with a grounding layer as the outermost layer of a mold coil in order to reduce the air insulation distance in the panel of the mold transformer and improve safety. May be used. When forming the outer ground layer with these devices, generally, the surface of the resin mold layer of the resin mold coil formed by resin casting or impregnation is roughened by sandblasting, etc., and then the surface is sprayed with a metal. A conductive layer is being formed.

Further, as a simpler method, a method of applying a conductive paint in which conductive fine particles such as carbon powder or metal powder are dispersed in an insulating resin to the surface of a resin mold layer, or conductive or semi-conductive There is also a method of forming a surface conductive layer by winding a flexible tape around the outer peripheral surface of the resin mold layer.

[0004]

By the way, the surface conductive layer provided on the surface of the resin mold coil used for such an induction device such as a transformer suppresses the eddy current generated by the interlinking magnetic flux, so that the magnetic flux density is reduced. It is necessary to have an appropriate electric resistance according to. However, in the case where the surface conductive layer is formed by metal spraying as described above, since the conductivity of the metal is relatively high, it is necessary to form an extremely thin conductive layer in order to obtain an appropriate electric resistance. There is a problem that forming an ultrathin conductive layer by metal spraying involves considerable difficulty.

In the sandblasting process and the metal spraying process, thermal and mechanical stress on the resin mold layer is large, so that cracks and scratches are generated on the surface of the resin mold layer, and the gap between the resin mold layer and the surface conductive layer. There was also a problem that minute defects were formed on the surface. Such minute defects cause cracks in the resin mold layer and cause partial discharge, which in turn lowers the insulation performance of the device.

Further, in the method of applying the conductive coating material, there is a problem that the uneven distribution of the conductive fine particles dispersed in the insulating resin is likely to occur, and it is difficult to obtain a uniform conductive layer. Furthermore, in the method of winding a conductive or semi-conductive tape, in order to obtain the optimum electric resistance, it is necessary to prepare tapes having various electrical conductivity according to the interlinkage magnetic flux density. It was difficult to form a uniform conductive layer. When the tape is wound, there is also a problem that a minute void is generated in the lap portion of the tape, resulting in the same defect as described above.

The present invention has been made in view of the above circumstances, and an object thereof is to form a surface conductive layer on the surface of a resin mold layer, and to obtain a uniform surface conductive layer with appropriate conductivity. Another object of the present invention is to provide a resin-molded coil that is capable of achieving excellent crack resistance and partial discharge resistance.
Another object of the present invention is to form a surface conductive layer on the surface of a resin mold layer, which is capable of easily obtaining a uniform surface conductive layer with appropriate conductivity. There is a way to provide.

[0008]

According to a first aspect of the present invention, there is provided a resin mold coil, wherein a winding formed by winding a conductor is molded with an insulating resin, and the surface of the resin mold layer is electrically conductive. It is characterized in that a surface conductive layer made of a conductive polymer is provided.

In this case, the surface conductive layer may be composed of a solvent-soluble conductive polymer (the invention of claim 2) or may be composed of a solvent-insoluble conductive polymer (claim). (Invention of item 3), and further, it can be composed of a complex-type conductive polymer (invention of claim 4).

A method for forming a surface conductive layer of a resin mold coil according to a fifth aspect of the present invention is a method for forming the surface conductive layer according to any one of the first to third aspects. In a state in which the resin mold coil is dipped in a solution containing a monomer molecule of a conductive polymer, a polymerization reaction is caused at the surface portion of the resin mold layer to form the surface conductive layer. It has characteristics.

[0011]

According to the resin mold coil of the first aspect of the present invention, the surface conductive layer formed on the surface of the resin mold layer comprises:
It is composed of a conductive polymer. At this time, the conductivity (electrical resistance) of the conductive polymer can be adjusted by adjusting the concentration of the added electron-donating or electron-affinic impurities, and therefore, the optimum thickness can be selected according to the flux linkage density. Thus, the surface conductive layer having electric resistance can be formed.

Unlike the conductive paint, the conductive polymer itself has conductivity, so that a uniform and thin surface conductive layer can be formed. Furthermore, since the surface conductive layer made of a conductive polymer can be formed by a thin film forming method such as vacuum deposition or CVD (chemical vapor deposition), or a method such as coating, the surface of the resin mold layer can be thermally treated. In addition, it is possible to do without mechanical stress, and it is possible to suppress the formation of minute defects.

In this case, if the surface conductive layer is composed of a solvent-soluble conductive polymer (resin mold coil according to claim 2), the conductive polymer dissolved in the solvent is applied to the surface of the resin mold layer. The surface conductive layer can be formed by such a simple method. Incidentally, as such a solvent-soluble conductive polymer, for example, a conjugated conductive polymer such as 3-hexyl polythiophene can be adopted.

If the surface conductive layer is made of a solvent-insoluble conductive polymer (resin mold coil according to claim 3), the conductive polymer has high chemical resistance, acid resistance and heat resistance. The surface conductive layer having excellent chemical resistance and heat resistance can be obtained. As such a solvent-insoluble conductive polymer, a conjugated conductive polymer such as polythiophene, polypyrrole, or polyacetylene can be used.

Further, if the surface conductive layer is composed of a complex type conductive polymer (resin molded coil of claim 4),
For example, a surface conductive layer having high conductivity in the thickness direction and low conductivity in the plane direction, that is, high conductivity anisotropy can be formed. Here, the eddy current generated by the flux linkage is
Since it flows in the surface direction of the surface conductive layer, it is possible to suppress the generation of eddy currents while ensuring appropriate conductivity in the thickness direction. As such a complex-type conductive polymer, TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane), metal or non-metal phthalocyanine, or the like can be used.

According to the method of forming the surface conductive layer of the resin mold coil of claim 5 of the present invention, the resin mold layer is immersed in the solution containing the monomer molecules of the conductive polymer. Since the conductive polymer is attached by causing a polymerization reaction on the surface part of the resin, the surface of the resin mold layer can be easily applied not only to the solvent-soluble conductive polymer but also to the solvent-insoluble conductive polymer. The surface conductive layer can be evenly formed in an arbitrary thickness. Further, the conductivity of the surface conductive layer can be adjusted by the concentration of the monomer molecules and the thickness of the adhesion, and the surface conductive layer having the optimum conductivity can be formed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings. (1) First Embodiment First, a first embodiment of the present invention (corresponding to claims 1 and 2) will be described with reference to FIGS. 1 and 2.

FIG. 1 schematically shows the structure of a resin mold coil 1 used in an induction device such as a transformer. Here, the resin mold coil 1 according to the present embodiment is
A winding 3 formed by winding a conductor (element wire) 2 with an insulating coating a large number of times is molded by a resin mold layer 4 made of an insulating resin such as epoxy resin. The resin mold layer 4 is formed by a method such as casting or impregnating an insulating resin so as to cover the outer surface of the winding 3 and penetrate into the gap between the conductors 2 inside.

As shown in FIG. 2, the surface of the resin mold layer 4 is provided with a surface conductive layer 5 made of a conductive polymer that functions as an outer ground layer. In this case, the surface conductive layer 5 is composed of a solvent-soluble conductive polymer such as 3-hexyl polythiophene.

The surface conductive layer 5 is formed by applying a solution of 3-hexylpolythiophene dissolved in a suitable solvent to the surface of the resin mold layer 4 and drying it. At this time, by adjusting the concentration of 3-hexylpolythiophene in the solution, the concentration of the added electron-donating or electron-affinic impurities, the adjustment of the number of coatings, etc.
The thickness and conductivity of the formed surface conductive layer 5 are optimized to correspond to the interlinkage magnetic flux density.

In such a structure, unlike the case where the surface conductive layer is formed by spraying a metal having a relatively high conductivity, the conductivity of the surface conductive layer 5 made of a conductive polymer can be easily and arbitrarily adjusted. It is possible to obtain the surface conductive layer 5 having an optimum electric resistance with an arbitrary thickness. Further, unlike the conductive paint, since the conductive polymer itself has conductivity, the surface conductive layer 5 having a uniform conductivity can be formed in any thickness.

Since the surface conductive layer 5 can be formed by applying a solution in which a solvent-soluble conductive polymer is dissolved to the surface of the resin mold layer 4, unlike the sandblasting process or the metal spraying process. Therefore, it is possible to avoid applying thermal and mechanical stress to the resin mold layer 4, and it is possible to suppress the formation of minute defects.

Therefore, according to the present embodiment, the surface conductive layer 5
Since is composed of a conductive polymer, it is possible to obtain a uniform surface conductive layer 5 with appropriate conductivity. Moreover, in this embodiment, since the solvent-soluble conductive polymer is adopted,
The surface conductive layer 5 is extremely easy to form, and since minute defects do not occur in the forming process, the resin mold coil 1 is excellent in crack resistance and partial discharge resistance, and thus highly reliable in insulation performance. Can be.

In this embodiment, the surface conductive layer 5 is formed by applying a solution in which a solvent-soluble conductive polymer is dissolved, but a thin film forming method such as vacuum deposition or CVD may be adopted. Similarly, the surface conductive layer 5 can be easily formed without thermal or mechanical stress.

(2) Second Embodiment Next, a second embodiment of the present invention (corresponding to claims 1, 3 and 5) will be described with reference to FIGS. 3 to 5. As shown in FIG. 3, the resin mold coil 6 according to the present embodiment includes a winding 3 formed by winding a conductor (element wire) 2 that is also covered with an insulating coating a large number of times from an insulating resin such as an epoxy resin. The resin mold layer 4 is formed by molding, and the surface of the resin mold layer 4 is provided with a surface conductive layer 7 made of a solvent-soluble conductive polymer such as polythiophene.

Then, in this embodiment, the surface conductive layer 7 is formed as follows. That is, FIG. 4 shows an apparatus configuration for forming the surface conductive layer 7. In the reaction tank 8, a conductive polymer monomer molecule (thiophene monomer) M and an electrolyte as shown in FIG. Contains a monomer solution 9 dissolved in
The resin mold coil 6 before the surface conductive layer 7 is formed and the counter electrode 10 are immersed in the monomer solution 9. The positive side of the DC power supply 11 is connected to the lead wire 3a of the winding 3 of the resin mold coil 6 via the variable resistor 12, and the negative side is grounded. The counter electrode 10 is also grounded.

In this state, when an appropriate potential is applied to the resin mold coil 6 by adjusting the variable resistor 12, as shown in FIG.
Polythiophene is generated and attached on the surface of the resin mold layer 4 and the surface conductive layer 7 is formed. In this case, the conductive polymer can be evenly attached to the surface of the resin mold layer 4, and the surface conductive layer 7 can have an arbitrary thickness depending on the processing time. Further, by adjusting the concentration of the monomer molecules M and the electrolyte of the monomer solution 9 and the thickness of the surface conductive layer 7, the surface conductive layer 7 having a desired conductivity can be obtained.

According to the resin mold coil 6 of this embodiment, the conductivity of the surface conductive layer 7 made of a conductive polymer can be easily and arbitrarily adjusted as in the first embodiment. It is possible to obtain the surface conductive layer 7 having an optimum electric resistance with an arbitrary thickness. Further, the surface conductive layer 7 having uniform conductivity can be obtained. Moreover, since the surface conductive layer 7 is composed of a solvent-insoluble conductive polymer having high chemical resistance, acid resistance, and heat resistance, the surface conductive layer 7 has excellent chemical resistance and heat resistance. Is something that can be done.

When the surface conductive layer 7 is formed, a polymerization reaction of the monomer molecules M in the monomer solution 9 is caused on the surface portion of the resin mold layer 4 so that the conductive polymer is attached. Even a solvent-insoluble conductive polymer can be easily attached to the surface portion of the resin mold layer 4, and the surface conductive layer 7 can be uniformly formed with an arbitrary thickness. Further, the conductivity of the surface conductive layer 7 can be arbitrarily adjusted by the concentration of the monomer molecule M and the thickness of the adhesion, and the surface conductive layer 7 having the optimum conductivity can be easily formed. further,
This method can suppress the formation of minute defects in the resin mold layer 4 and is of course excellent in crack resistance and partial discharge resistance.

(3) Third Embodiment FIGS. 6 to 8 show a third embodiment of the present invention (claims 1 and 2).
4) is shown. As shown in FIG. 6, in the resin mold coil 13 according to the present embodiment, a winding 3 formed by winding a conductor (element wire) 2 that also has an insulating coating is wound many times from an insulating resin such as an epoxy resin. Molded with the resin mold layer 4 that is formed on the surface of the resin mold layer 4,
It is configured by forming a surface conductive layer 14 made of a complex conductive polymer, for example, a metal complex of phthalocyanine.

In this case, as shown in FIG. 7, the phthalocyanine metal complex molecule P forms a plate-like molecular crystal,
In the surface conductive layer 14, high conductivity is exhibited in the stacking direction of the plate-like molecules P. Therefore, as shown in FIG. 8, by forming the surface conductive layer 14 so that the stacking direction of the molecules P is the thickness direction (Z-axis direction), the height in the in-plane direction (XY plane direction) is increased. With respect to the resistance, the surface conductive layer 14 having a low resistance in the thickness direction, that is, having high anisotropy of conductivity can be obtained.

As a result, as shown in FIG. 8, the interlinkage magnetic flux F
Since the eddy current E generated in the surface conductive layer 14 by the current flows in the surface direction of the surface conductive layer 14, the eddy current E is generated.
Is restricted by the high resistance, and the generation of the eddy current E can be suppressed in a state where proper conductivity is secured in the thickness direction.

Therefore, according to this embodiment, it is possible to obtain the surface conductive layer 14 having an appropriate conductivity and uniform, and in addition to being excellent in the crack resistance and the partial discharge resistance, the generation of the eddy current E is caused. Can be suppressed more effectively.

(4) Fourth Embodiment Finally, FIG. 9 shows a fourth embodiment of the present invention. The present invention is applied to a resin mold coil 15 having a composite structure such as a stator coil of a motor. It is applied. That is, the winding wire 16 is fitted into the slot of the iron core 17, and in this state, the resin mold layer 18 is formed by the impregnation process of the insulating resin. A surface conductive layer 19 made of a conductive polymer is formed on the surface of the resin mold layer 18 so as to cover the end portion of the iron core 17.

In this case, the surface conductive layer 19 is provided for the purpose of relaxing the electric field at the end portion of the iron core 17, and is formed so as to have the optimum conductivity for relaxing the electric field. Also in this embodiment, it is possible to obtain a uniform surface conductive layer 19 having an appropriate electric conductivity, and to obtain the same effect as that of the above-described first embodiment that the crack resistance and the partial discharge resistance are excellent. Is something that can be done.

[0036]

As is apparent from the above description, the present invention has the following excellent effects. That is, according to the resin mold coil of claim 1, the surface conductive layer is formed on the surface of the resin mold layer, and since the surface conductive layer is made of the conductive polymer, it has an appropriate conductivity and is uniform. It is possible to obtain an excellent surface conductive layer, and further, it becomes excellent in crack resistance and partial discharge resistance, and the reliability can be greatly improved.

In this case, if the surface conductive layer is made of a solvent-soluble conductive polymer (resin mold coil of claim 2), the conductive polymer dissolved in the solvent is applied to the surface of the resin mold layer. The surface conductive layer can be formed by such a simple method.

If the surface conductive layer is made of a solvent-insoluble conductive polymer (resin-molded coil according to claim 3), the conductive polymer has high chemical resistance, acid resistance, and heat resistance. The surface conductive layer having excellent chemical resistance and heat resistance can be obtained.

Furthermore, if the surface conductive layer is composed of a complex type conductive polymer (resin molded coil according to claim 4),
For example, it is possible to form a surface conductive layer having high conductivity in the thickness direction and low conductivity in the plane direction, that is, high conductivity anisotropy, and it is possible to effectively suppress the generation of eddy currents. is there.

According to the method of forming the surface conductive layer of the resin mold coil of claim 5, the surface portion of the resin mold layer is immersed in the solution containing the monomer molecules of the conductive polymer in the resin mold coil. Since a conductive polymer is made to adhere by causing a polymerization reaction in, the solvent-soluble conductive polymer as well as the solvent-insoluble conductive polymer easily adheres to the surface part of the resin mold layer. It is possible to easily form a uniform surface conductive layer having appropriate conductivity.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention, and is a perspective view of a resin-molded coil with a part broken away.

FIG. 2 is an enlarged vertical sectional view of a surface layer portion of a resin molded coil.

FIG. 3 is a diagram corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 4 is a diagram showing an apparatus configuration for forming a surface conductive layer.

FIG. 5 is a diagram schematically showing a state of a polymerization reaction on the surface portion of the resin mold layer.

FIG. 6 is a view corresponding to FIG. 1 showing a third embodiment of the present invention.

FIG. 7 is a diagram schematically showing how molecules are stacked in the surface conductive layer.

FIG. 8 is a diagram schematically showing the relationship between the interlinkage magnetic flux and the eddy current with respect to the surface conductive layer.

FIG. 9 shows a fourth embodiment of the present invention and is a vertical cross-sectional view showing the main part.

[Explanation of symbols]

In the drawing, 1, 6, 13 and 15 are resin molded coils and 2
Is a conductor, 3 and 16 are windings, 4 and 18 are resin mold layers,
5, 7, 14, and 19 are surface conductive layers, 8 is a reaction layer, 9 is a monomer solution, 10 is a counter electrode, and 17 is an iron core.

Claims (5)

[Claims] 1. A resin mold in which a winding formed by winding a conductor is molded with an insulating resin, and a surface conductive layer made of a conductive polymer is provided on the surface of the resin mold layer. coil. 2. The resin mold coil according to claim 1, wherein the surface conductive layer is made of a solvent-soluble conductive polymer. 3. The resin mold coil according to claim 1, wherein the surface conductive layer is made of a solvent-insoluble conductive polymer. 4. The resin mold coil according to claim 1, wherein the surface conductive layer is made of a complex conductive polymer. 5. A method for forming a surface conductive layer according to claim 1, wherein the resin mold coil is immersed in a solution containing monomer molecules of a conductive polymer. A method for forming a surface conductive layer of a resin mold coil, wherein the surface conductive layer is formed by causing a polymerization reaction on the surface of the resin mold layer.