JPH08316055A - Resin molded coil - Google Patents

Abstract

PURPOSE: To enhance the workability of molding work while eliminating the voids from resin by lowering the viscosity of resin while employing a crack retarding structure. CONSTITUTION: A winding 2 obtained by winding a conductor 5 is molded of epoxy resin containing a filter for retarding generation of crack. In such resin molded coil, a filmy insulator having roughened surface is employed as a coating insulator 4 for conductor thus setting a high content of filler in the resin at the peripheral part of the conductor 5 as compared with other parts.

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 obtained by molding a winding formed by winding a conductor with a resin such as an epoxy resin.

[0002]

2. Description of the Related Art A resin mold coil of this type has been conventionally used as a winding wire for a mold transformer, a mold reactor, etc. because of its excellent electric and mechanical properties. However, there is a problem that thermal stress is generated due to the difference between the linear expansion coefficient of the epoxy resin and the linear expansion coefficient of the conductor, and this thermal stress easily causes cracks. On the other hand, by incorporating a filler having a function of bringing the linear expansion coefficient of the epoxy resin close to the linear expansion coefficient of the conductor (that is, a filler for preventing crack generation) into the epoxy resin, the thermal stress can be reduced. A configuration is considered in which the size is made smaller so that cracks are less likely to occur.

[0003]

In the above-mentioned conventional one, there is a characteristic that the viscosity of the epoxy resin increases as the compounding amount of the filler in the epoxy resin is increased in order to make the cracks more difficult to occur. is there. When the viscosity of the epoxy resin is increased in this way, when molding the winding with the resin, it becomes difficult to inject the resin into the mold (so-called casting work), or voids tend to remain in the resin. There is a problem that In particular,
If voids remain, partial discharge is likely to occur there, making it impossible to use at high voltage. Therefore, it was actually difficult to increase the compounding amount of the filler in the resin.

Therefore, an object of the present invention is to prevent the occurrence of cracks sufficiently, to prevent the viscosity of the resin from increasing, to improve the casting workability, and to prevent voids from remaining in the resin. It is to provide a resin mold coil that can be prevented.

[0005]

A resin-molded coil according to the present invention is a resin-molded coil in which a winding formed by winding a conductor is molded with a resin containing a filler for preventing cracks from being generated. The resin is characterized in that the content of the filler contained in the resin is higher than the content of the filler contained in the resin in other portions. In the case of this configuration, as the inter-conductor insulator of the winding,
It is preferable to use a film-like insulator having a roughened surface.

It is also preferable that a film-like insulator having a projection on its surface is used as the inter-conductor insulator of the winding. Furthermore, it is also conceivable to use a non-woven fabric insulator as the inter-conductor insulator of the winding. On the other hand, it is also preferable that a film-like insulator having a roughened surface is sandwiched between the conductors of the winding. Further, it is also possible to sandwich a film-like insulator having a projection on the surface between the conductors of the winding. It is also conceivable to sandwich a non-woven fabric insulation between the conductors of the winding.

[0007]

According to the above means, the content of the filler contained in the resin in the peripheral portion of the conductor is made higher than the content of the filler contained in the resin in the other portion. It is possible to bring the linear expansion coefficient of the resin in the peripheral portion closer to the linear expansion coefficient of the conductor. As a result, the thermal stress generated between the resin and the conductor in the peripheral portion of the conductor is reduced, and thus cracks are more difficult to occur. Moreover, in the case of this configuration, since the resin having a low filling material content is used during the casting operation, the viscosity of the resin does not increase. Therefore, the workability during the casting operation does not deteriorate, and since the defoaming operation is simple, it is possible to sufficiently prevent the voids from remaining in the resin.

In the case of the above structure, if a film-like insulator having a roughened surface is used as the inter-conductor insulator of the winding, the content ratio of the filler contained in the resin in the peripheral portion of the conductor is concrete. Can be made higher than the content rate of the filler contained in the resin of the other part. That is, in the case of this configuration, when the resin is impregnated between the conductors of the winding during casting, specifically, the resin is impregnated between the conductor and the film-shaped insulator or between the film-shaped insulators. In doing so, relatively large particles of the filler contained in the resin are filtered by the roughened surface of the film-shaped insulating material and remain near the surface to aggregate. The agglomeration of the filler particles increases the content of the filler in the resin in the peripheral portion of the conductor.

Further, even if a film-like insulator having a projection on its surface or a non-woven fabric insulator is used as the inter-conductor insulator of the winding wire, the inclusion of the filler contained in the resin around the conductor is similarly performed. The rate can be increased. Furthermore, between the conductors of the winding, a film-shaped insulator with a roughened surface,
Even if a film-like insulator provided with protrusions on the surface or a non-woven fabric insulator is sandwiched, it is possible to increase the content ratio of the filler contained in the resin in the peripheral portion of the conductor in the same manner as the above-mentioned configurations. it can.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. First, in FIG. 2 showing a schematic configuration of a resin molded coil, in the resin molded coil 1, the winding 2 is provided with an insulating resin such as an epoxy resin 3.
It is configured by molding with. The winding 2 is configured by winding a conductor 5 whose outer peripheral portion is covered with a conductor coating insulator 4 as an inter-conductor insulator in a coil shape many times.
Here, when the winding wire 2 is molded with the epoxy resin 3, a method of casting the epoxy resin 3 is used, whereby the outer peripheral portion of the winding wire 2 is covered and a gap portion between the conductors 5 inside the winding wire 2 is covered. A resin mold layer 6 is formed so as to be impregnated therewith.

As shown in FIG. 3, the conductor-covered insulator 4 is made of a film-like insulator 7 having a roughened surface.
The conductor-covered insulator 4 is formed by winding and covering the film-shaped insulator 7 around the outer periphery of the conductor 5. The film-shaped insulator 7 is made of, for example, a film made of polyethylene terephthalate (PET), and both surfaces thereof can be roughened when the film is biaxially stretched. In this case, on both sides of the film having a thickness of about 25 to 75 μm,
A large number of convex portions and concave portions having a height of about several μm are formed to roughen the surface.

Now, the case of molding the winding wire 2 with the epoxy resin 3, that is, the case of performing a casting operation will be described. In this case, the epoxy resin 3 used for the casting is mixed with the filler at a low content rate in consideration of the casting workability, and the viscosity of the epoxy resin 3 is not so high. It has a configuration that can be executed relatively easily. The epoxy resin 3 is impregnated between the conductors 5 of the winding 2, specifically between the conductor 5 and the film-shaped insulator 7 (conductor-covered insulator 4) or between the film-shaped insulators 7. At this time, the epoxy resin 3 is impregnated into the gap formed by the convex portion and the concave portion on the surface of the film-shaped insulator 7.

At this time, relatively large particles of the filler contained in the epoxy resin 3 are filtered (filtered) by the convex portions or concave portions on the surface of the film-shaped insulator 7 to form a gap formed by the convex portions or concave portions. I can't get inside. As a result, the filler particles remain near the surface of the film-shaped insulator 7 and agglomerate. The aggregated portion of this filler is shown in FIG.
A cross-hatched area A in FIG. The content of the filler contained in the epoxy resin 3 in the peripheral portion of the conductor 5 becomes higher than the content of the filler contained in the other portion of the epoxy resin 3 due to the aggregation of the filler. .

According to this embodiment having such a structure, the content of the filler contained in the epoxy resin 3 in the peripheral portion of the conductor 5 of the winding 2 is made higher than that of the other portions. Since it is configured, it becomes possible to bring the linear expansion coefficient of the epoxy resin 3 around the conductor 5 closer to the linear expansion coefficient of the conductor 5. As a result, the thermal stress generated between the conductor 5 and the epoxy resin 3 (that is, the resin mold layer 6) in the peripheral portion of the conductor 5 is reduced, and cracks can be made more difficult to occur. Moreover, in the case of this configuration, since the epoxy resin 3 having a low filling material content is used during the casting operation, the epoxy resin 3 containing The viscosity decreases. Therefore, the workability during the casting work does not deteriorate, and the defoaming work of the epoxy resin 3 during the casting work can be performed efficiently and easily. Therefore, the epoxy resin 3 (resin mold layer 6) It is possible to sufficiently prevent voids from remaining inside. As a result, even if a high voltage is applied to the resin mold coil 1, it becomes difficult for partial discharge to occur, so that the resin mold coil 1 can be used at a high voltage.

Further, in the above-mentioned embodiment, the film-shaped insulator 7 having a roughened surface is used as the conductor-covered insulator 4. However, the conductor-coated insulator 4 is not limited to this. As in the second embodiment, a film-shaped insulator 8 having projections 8a on the surface may be used as the conductor-coated insulator 4. The film-shaped insulator 8 is made of, for example, a film made of polyethylene terephthalate (PET), and its thickness dimension is set to about 25 to 75 μm. By subjecting this film to so-called embossing, a large number of protrusions 8a having a height of several μm to several tens of μm are formed on the surface (the upper surface in FIG. 4). The configuration of the second embodiment other than the above is the same as the configuration of the first embodiment.

In the case of the second embodiment, however, the epoxy resin 3 is impregnated between the conductor 5 of the winding 2 and the film-shaped insulator 8 or between the film-shaped insulator 8. At this time, the epoxy resin 3 is impregnated into the gap formed by the protrusion 8a on the surface of the film-shaped insulator 8. At this time, the relatively large particles of the filler contained in the epoxy resin 3 are the protrusions 8 a on the surface of the film-shaped insulator 8.
Therefore, it is not possible to enter the gap formed by the projection 8a after being filtered by. As a result, the filler particles remain in the vicinity of the surface of the film-shaped insulator 8, that is, in the peripheral portion (vicinity portion) of the conductor 5 and aggregate. Therefore, the content rate of the filler contained in the epoxy resin 3 in the peripheral portion of the conductor 5 becomes higher than the content rate of the filler contained in the epoxy resin 3 in other portions. As a result, also in the second embodiment, it is possible to obtain substantially the same operational effects as in the first embodiment.

In the second embodiment described above, the film-shaped insulator 8 having the projections 8a on the surface is used as the conductor-coated insulator 4, but a non-woven fabric insulator may be used instead. good. As the non-woven fabric insulating material, it is preferable to use, for example, one in which the epoxy resin 3 can be impregnated inside by processing the aramidid fiber to have a density of about 50% of the case of calendering.

In the case of using the above-mentioned non-woven fabric insulation, when the epoxy resin 3 is impregnated into the non-woven fabric insulation, the filler particles larger than the fiber intervals of the non-woven fabric insulation are the fibers of the non-woven fabric insulation. Therefore, it is not possible to enter the inside of the non-woven fabric by being filtered. As a result, the particles of the filler remain and agglomerate near the surface of the non-woven fabric insulating material, that is, in the peripheral portion (vicinity portion) of the conductor 5. Therefore, the content of the filler contained in the epoxy resin 3 around the conductor 5 is higher than the content of the filler in other parts. As a result, even in the configuration using the non-woven fabric insulator, it is possible to obtain substantially the same operational effects as those of the first and second embodiments.

In each of the above-described embodiments, the conductor-covered insulator 4 covering the outer peripheral portion of the conductor 5 is provided in the film-shaped insulator 7 and the film-shaped insulator in order to provide an aggregated portion of the filler near the surface of the conductor 5. 8 or a non-woven fabric insulator, but instead of this, it may be constructed as in the third embodiment of the present invention shown in FIG. Specifically, as shown in FIG. 5, between the conductors 5 of the winding wire 2, a film-shaped insulator (first surface) having a roughened surface is formed.
The same as the film-like insulator 7 of the above example), a film-like insulator having protrusions on its surface (substantially the same as the film-like insulator 8 of the second embodiment) or a non-woven fabric insulator. The object 9 is configured to be sandwiched.

In the case of the above-mentioned third embodiment, the conductor-coated insulating material 4 for covering the outer peripheral portion of the conductor 5 is a film-shaped insulating material whose surface is not roughened or a film in which no projection is provided on the surface. May be made of a linear insulator, or
You may comprise from the film-like insulator 7 of the 1st Example, the film-like insulator 8 of the 2nd Example, or the nonwoven fabric insulator.
The configuration of the third embodiment other than the above is the same as the configuration of the first embodiment.

In the case of the above-mentioned third embodiment, the epoxy resin 3 is placed between the conductors 5 of the winding 2 and the conductor-coated insulator 4 is formed.
When impregnated in the space, the epoxy resin
The relatively large particles of filler contained in are filtered. As a result, the particles of the filler are near the surface of the gap insulator 9, that is, the peripheral portion (vicinity portion) of the conductor 5.
Will remain and aggregate. As a result, the content of the filler contained in the epoxy resin 3 around the conductor 5 is
It becomes higher than the content rate of other parts. Therefore, also in the third embodiment, it is possible to obtain substantially the same operational effects as those of the first or second embodiment.

[0022]

As is apparent from the above description, the present invention makes the content of the filler contained in the resin in the peripheral portion of the conductor higher than the content of the filler contained in the resin in other portions. Since it is configured as described above, it is possible to prevent the viscosity of the resin from increasing while improving the casting workability while preventing the formation of cracks sufficiently, and it is also possible to prevent voids from remaining in the resin. Produce an effect.

In the case of the above-mentioned structure, if a film-like insulator having a roughened surface is used as the inter-conductor insulator of the winding, the content ratio of the filler contained in the resin around the conductor is actually It is possible to configure the content higher than the content of the filler contained in the resin of the other part. Further, even if a film-like insulator or a non-woven fabric insulator having a projection on its surface is used as the inter-conductor insulator of the winding, the content of the filler contained in the resin around the conductor is similarly increased. can do. On the other hand, between the conductors of the winding, a film-like insulator having a roughened surface, a film-like insulator having projections on the surface, or a non-woven fabric insulator may be sandwiched between the conductors in the same manner. It is possible to increase the content rate of the filler contained in the resin.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a resin mold coil showing a first embodiment of the present invention.

FIG. 2 is a cutaway perspective view of a resin molded coil.

FIG. 3 is a cutaway perspective view of a film-shaped insulator.

FIG. 4 is a diagram corresponding to FIG. 3 showing a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a main part of a winding showing a third embodiment of the present invention.

[Explanation of symbols]

1 is a resin molded coil, 2 is a winding wire, 3 is an epoxy resin, 4 is a conductor coating insulator (interconductor insulator), 5 is a conductor,
7 is a film-shaped insulator, 8 is a film-shaped insulator, 8a is a protrusion, and 9 is a space insulator.

Claims (7)

[Claims] 1. A resin-molded coil in which a winding formed by winding a conductor is molded with a resin containing a filler for preventing cracks, wherein the filler is contained in the resin around the conductor. The resin molded coil is configured so that the rate is higher than the content rate of the filler contained in the resin of the other portion. 2. The resin-molded coil according to claim 1, wherein a film-shaped insulating material having a roughened surface is used as the inter-conductor insulating material of the winding. 3. The resin-molded coil according to claim 1, wherein a film-shaped insulator having projections on its surface is used as the conductor-to-conductor insulator of the winding. 4. The resin-molded coil according to claim 1, wherein a non-woven fabric insulator is used as the inter-conductor insulator of the winding. 5. A film-like insulator having a roughened surface is sandwiched between conductors of the winding.
The resin molded coil described. 6. The resin-molded coil according to claim 1, wherein a film-shaped insulator having projections on its surface is sandwiched between conductors of the winding. 7. The resin mold coil according to claim 1, wherein a non-woven fabric insulator is sandwiched between conductors of the winding.