JP3359843B2 - Resin molded transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-molded transformer winding, and more particularly to a secondary winding wound around a core in a plurality of layers, a main insulating layer wound on the secondary winding, and a main winding. The present invention relates to preventing the primary winding wound on an insulating layer from being displaced in a winding axis direction of a main insulating layer and improving resin impregnation between a main insulating layer and a final layer of a secondary winding.

[0002]

2. Description of the Related Art FIG. 6 is a perspective view of a winding portion constituting a conventional resin-molded transformer disclosed in Japanese Utility Model Publication No. 3-41449. In the drawing, reference numeral 1 denotes a core formed by pressing a press board or the like into a circular shape, 2 denotes a secondary winding wound on the core 1 in a plurality of layers, 3 denotes an interlayer insulating paper of the secondary winding 2, and 4 denotes a secondary winding. A main insulating layer wound a plurality of times on the secondary winding 2 and is formed by winding insulating paper such as a polyester film. 5
Is a primary winding wound on the main insulating layer 4. The winding portion configured as described above is arranged in a mold 6 as shown in FIG. 7, and a synthetic resin 7 such as an epoxy resin is injected to form a resin-molded transformer.

Next, the operation will be described. Since the core 1 uses a press board or the like which is a material that easily absorbs moisture in the air, it absorbs moisture in the air. The secondary winding 2 wound on the core 1 in a plurality of layers has an interlayer insulating paper 3. Main insulation layer 4 wound multiple times on secondary winding 2
Is formed by winding an insulating paper such as a polyester film, and some moisture in the air adheres between the layers.

Accordingly, before molding with the synthetic resin 7, the winding is heated and dried in order to remove the water absorbed and adhered to the winding. This temperature is set at about 100 ° C. to 120 ° C. At this time, vacuum drying may be performed in order to speed up water removal. This moisture removal is performed in order to prevent the occurrence of voids when the moisture is present in the winding portion during molding to prevent the insulation performance from being significantly reduced.

[0005]

In the conventional manufacturing process, it is common to dry the winding portion to remove moisture from the winding portion before molding the synthetic resin. The main insulating layer, which is formed by winding insulating paper such as a polyester film, has a heating temperature of 100 to 120 ° C. when the winding portion is dried.
There is a difference in the coefficient of thermal expansion between the secondary winding made of a copper wire and the main insulating layer made of a polyester film or the like, and the coefficient of thermal expansion is “copper wire <polyester film”.

[0006] For this reason, a small gap is formed between the secondary winding and the main insulating layer, and a deviation in the winding axis direction easily occurs between the secondary winding and the main insulating layer. Conversely, the main insulating layer and the primary winding become tight. When placing the winding part in the mold, make it a temperature that can be handled manually, but before injecting the synthetic resin,
To improve the impregnation of the synthetic resin, once again
Heated to about 20 ° C.

For this reason, when a minute gap is generated again between the secondary winding and the main insulating layer, and a deviation in the winding axis direction is likely to occur between the secondary winding and the main insulating layer, the winding portion is removed. When set in a mold, or when transported for injecting a synthetic resin into the mold, it moves with a slight impact, so that care must be taken during handling. This is because if the gap between the secondary winding and the main insulation layer in the direction of the winding axis occurs, the insulation thickness of the synthetic resin becomes uneven, and the product is liable to cracks and dielectric breakdown. There was a problem that reduced the properties.

Further, the contact between the secondary winding and the main insulating layer is closest to the high-voltage primary winding, and where there is an air layer (void), insulation deterioration due to corona generation is likely to occur. Yes, it is necessary to completely impregnate the synthetic resin into the delta strip space formed between the secondary winding and the main insulating layer,
Synthetic resin could only penetrate into the area where the secondary winding and the main insulating layer were in close contact with each other between the lines of the secondary winding, and it was difficult to completely eliminate voids.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has a secondary winding wound around a core in a plurality of layers and a main insulating layer wound on the secondary winding in a plurality of layers. A belt-shaped insulating paper is fixed with a secondary winding so as to prevent displacement in the axial direction, and both ends of the insulating paper are wound around the main insulating layer and fixed,
It is an object of the present invention to provide a structure capable of preventing displacement of the main insulation in the winding axis direction and simultaneously impregnating the uppermost layer of the secondary winding closest to the high-voltage primary winding with resin.

[0010]

(1) A resin-molded transformer according to the present invention comprises a secondary winding wound around a core in a plurality of layers, and a plurality of insulating layers provided on the secondary winding. In the resin mold transformer formed by impregnating the main insulating layer formed by the above and the primary winding wound on the main insulating layer with the resin, the final layer of the secondary winding and the layer thereunder are formed. In between, a plurality of insulating bands arranged so that both ends in the longitudinal direction protrude from both ends in the winding axis direction of the secondary winding are arranged in the winding direction of the secondary winding, and a plurality of insulating bands are arranged in the winding direction of the secondary winding. Both ends are bent and sandwiched between the layers of the main insulating layer.

(2) In addition, both ends of the insulating band sandwiched between the main insulating layers do not overlap when viewed from above.

(3) Further, the insulating band is arranged obliquely with respect to the winding axis direction, and the bent both ends of the insulating band are arranged so as to be substantially parallel without overlapping when viewed from above.

(4) In the vicinity of both ends of the secondary winding in the direction of the winding axis, an insulating band is provided between the last layer of the secondary winding and a layer therebelow, and at the center in the direction of the winding axis, the insulating band is formed. A band is arranged on the last layer of the secondary winding.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a perspective view of a winding portion of a resin-molded transformer according to the present invention. FIG. 2 is a sectional view of a winding portion of the resin-molded transformer according to Embodiment 1 of the present invention. In the figure, reference numerals 1 to 5 are the same as those described in the conventional example. Reference numeral 8 denotes an insulating band longer than the width of the secondary winding 2 in the winding axis direction, and the winding end layer of the secondary winding 2 (hereinafter, simply referred to as the last layer) with the central portion in the winding axis direction.
At a plurality of locations in the circumferential direction between the main insulating layer 4 and the main insulating layer 4.

The insulating band 8 arranged in this manner is fixed by the winding of the last layer of the secondary winding 2, and furthermore, both ends of the insulating band 8 are wound between the main insulating layers 4 and fixed. The gap between the winding 2 and the main insulating layer 4 in the winding axis direction is eliminated. Therefore, even if a small gap is formed between the secondary winding 2 and the main insulating layer 4 due to a thermal expansion difference caused by heating at 100 ° C. to 120 ° C. at the time of partial drying of the winding, 8 prevents displacement in the winding axis direction.

Since the winding of the final layer of the secondary winding 2 is provided with a resin impregnation path corresponding to the thickness of the insulating band on the side of the insulating band 8, the final layer of the secondary winding 2 and its Since resin is impregnated between the lower layers, the resin is impregnated into the delta-shaped space formed by the secondary winding 2 and the main insulating layer 4 of the final layer from between the winding lines, thereby eliminating voids and insulating. A highly reliable product can be obtained. The resin impregnation from the side of the insulating band 8 to the entire outer periphery of the winding is performed through the space in the winding direction of the secondary winding 2.

As described above, in this embodiment, the insulating band prevents the displacement of the main insulating layer in the winding axis direction, and the path through which the molding resin impregnates the final layer of the secondary winding and the main insulating layer. Since it was made possible, voids could not be made,
Products with high insulation reliability can be obtained. In addition, there is an effect that workability is improved and a product can be manufactured at low cost.

Embodiment 2 FIG. In the first embodiment, when the insulating band 8 is wound between the main insulating layers 4, both ends of the insulating band 8 are overlapped and fixed between the main insulating layers 4. The main insulating layer 4 is partially thickened, and the distance between the primary winding 5 and the secondary winding 2 is partially uneven. If the distance between the primary winding 5 and the secondary winding 2 is non-uniform, the electric field intensity becomes non-uniform and partial discharge and corona easily occur, so the distance between the primary winding 5 and the secondary winding 2 is made as uniform as possible. It is desirable.

FIG. 3 is a sectional view of a winding portion of a resin-molded transformer according to a second embodiment of the present invention. In the figure, 1 to 5 and 8 are the same as those in the first embodiment. In the second embodiment, as shown in FIG. 3, both ends of the insulating band 8 have a length that does not overlap, and are wound between the main insulating layers 4. Thus, since both ends of the insulating band 8 do not overlap between the main insulating layers 4, partial thickening of the main insulating layer 4 is eased. Since the resin impregnated in the space formed between both ends of the insulating band 8 between the main insulating layers 4 by the resin impregnating path on the side of the insulating band 8, the weak point of the insulating strength does not occur.

Embodiment 3 In the first and second embodiments, both ends of the insulating band 8 are fixed by winding both ends of the insulating band 8 during winding of the main insulating layer 4, but tension is not applied from both ends of the insulating band 8. The exposed portion of the insulating band 8 is loose, and this loosening causes a displacement in the winding axis direction between the secondary winding 2 and the main insulating layer 4. In the third embodiment, the exposed portion is not loosened.

FIG. 4 is a perspective view of a winding portion of a resin-molded transformer according to Embodiment 3 of the present invention. In the figure, 1 to 5 and 8 are the same as those in the first embodiment. In the third embodiment, as shown in FIG. 4, the insulating band 8 is arranged obliquely with respect to the winding axis so that both ends of the insulating band 8 are parallel to the main insulating layer 4 and do not overlap. To When the both ends of the insulating band 8 are folded in the middle of the winding of the main insulating layer 4 to fix both ends of the insulating band 8, both ends are pulled together, and the main insulating layer 4 is wound. After completion, unnecessary portions at both ends of the insulating band 8 are cut.

With this configuration, the exposed portion of the insulating band 8 is not loosened, and the positional relationship between the secondary winding 2 and the main insulating layer 4 can be fixed at all times without any deviation.

Embodiment 4 FIG. 5 is a sectional view of a winding portion of a resin-molded transformer according to a fourth embodiment of the present invention. In the figure, 1 to 5 and 8 are the same as those in the first embodiment. In the fourth embodiment, as shown in FIG. 5, the insulating band 8 is arranged on the uppermost layer of the secondary winding 2, and the portions near both end surfaces of the secondary winding 2 are arranged on the final layer of the secondary winding 2. And a layer thereunder, and the central portion is folded back halfway so as to be on the final layer of the secondary winding 2.

As described above, by setting the central portion of the insulating band 8 on the final layer of the secondary winding 2, the main insulating layer 4 wound from above the secondary winding 2 and the insulating band 8 Are directly in contact with each other, and fixation to the secondary winding 2 is performed by the final layer of the secondary winding 2 at a portion near both end faces of the secondary winding 2 and a layer thereunder. And insulation band 8
The ends of the insulating band 8 are fixed to the secondary winding 2 and the main insulating layer 4 by folding both ends of the insulating band 8 between the main insulating layers 4.

With such a structure, the main insulating layer 4
Thus, a resin impregnation path to the central portion of the boundary between the secondary winding 2 and the secondary winding 2 is ensured, and the resin impregnation is sufficient. Therefore, it is possible to manufacture a molded transformer in which the number of voids is small and the displacement of the secondary winding 2 and the main insulating layer 4 in the winding axis direction is prevented.

Embodiment 5 In the first embodiment, as shown in FIG. 2, both ends of the insulating band 8 are wound between the same layers of the main insulating layer 4, but they do not necessarily have to be between the same layers.
For example, one end of the insulating band 8 may be wound into the third layer from below the main insulating layer, and the other end may be wound into the fifth layer from below.

FIGS. 3 and 4 of the second embodiment.
In FIG. 5 and the like, both ends of the insulating band are wrapped between the same layers of the main insulating layer, but they may be wrapped between different layers. In this case, in FIGS. 3 and 5, both ends of the insulating band are not overlapped. However, even when the insulating band is wrapped in another layer, the both ends are interposed through some insulating layers of the main insulating layer, To avoid overlap.

In the third embodiment, the insulating strips are arranged obliquely with respect to the direction of the winding axis of the winding. However, the same applies in this case so that both ends of the insulating strips do not overlap when viewed from above. .

[0029]

As described above, according to the present invention, the insulating band is provided to prevent the main insulating layer of the resin-molded transformer from being displaced in the winding axis direction. Since the path through which the molding resin is impregnated into the insulating layer is formed, voids are not formed, and a product having high insulation reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a winding portion of a resin-molded transformer according to the present invention.

FIG. 2 is a sectional view of a winding portion of the resin-molded transformer according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a winding portion of a resin-molded transformer according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a winding part of a resin-molded transformer according to a third embodiment of the present invention.

FIG. 5 is a sectional view of a winding part of a resin-molded transformer according to a fourth embodiment of the present invention.

FIG. 6 is a perspective view of a winding portion of a conventional resin molded transformer.

FIG. 7 is a cross-sectional view of a conventional resin-molded transformer in which a winding portion is arranged in a mold.

[Explanation of symbols]

1 core, 2 secondary winding, 3 interlayer insulating paper, 4 main insulating layer, 5 primary winding,
6 mold, 7 synthetic resin,
8 Insulation strip

Claims (4)

(57) [Claims] A secondary winding wound around a core in a plurality of layers; a main insulating layer formed of a plurality of insulating layers on the secondary winding;
In a resin-molded transformer formed by impregnating a primary winding wound on the main insulating layer with a resin, between a final layer of the secondary winding and a layer thereunder, both ends in a longitudinal direction thereof are provided. A plurality of insulating bands are arranged in the winding direction of the secondary winding, and a plurality of insulating bands are arranged in the winding direction of the secondary winding so as to protrude from both ends in the winding axis direction of the secondary winding. A resin-molded transformer characterized by being sandwiched between layers. 2. The resin-molded transformer according to claim 1, wherein both ends of the insulating band sandwiched between the main insulating layers are configured not to overlap when viewed from above. 3. The insulating band is disposed obliquely with respect to the direction of the winding axis, and the bent both ends of the insulating band are arranged so as to be substantially parallel without overlapping when viewed from above. 2. The resin molded transformer according to claim 1. 4. In the vicinity of both ends in the direction of the winding axis of the secondary winding, an insulating band is provided between the last layer of the secondary winding and a layer thereunder. The resin-molded transformer according to any one of claims 1 to 3, wherein the transformer is arranged on a final layer of the secondary winding.