JPH0339806B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a method for manufacturing resin molded windings for stationary induction electric appliances such as transformers and reactors.

[Prior art and its problems]

In recent years, there has been increasing interest in making substation equipment incombustible or flame retardant, mainly from the standpoint of disaster prevention, in substations installed in urban areas or underground buildings, and resin molded transformers with excellent flame retardancy have attracted attention. Voltage ranges from several KV to several
Transformers with various rated voltages and rated capacities of 10 KV and capacities ranging from several KVA to several MVA are in practical use, and when manufacturing them, several dozen types of molds are used depending on the voltage, capacity, etc. Since multiple units of each type need to be kept at all times, equipment costs, storage, and management costs are high, and this is a major factor in increasing product costs, so there is a strong need to rationalize manufacturing methods. .

Fig. 6 and Fig. 7 are explanatory diagrams of the conventional manufacturing method, Fig. 6 is an external view of the casting mold seen from the side, and Fig. 7 is a cross-sectional view seen from the axial direction. This figure shows an example of a case where the casting process is performed with the terminal part facing upward. In the figure, the casting mold includes a cylindrical inner mold 1, an outer mold 2 equipped with an embedded terminal fitting 4 and a pouring spout 3, and a sheet-like mold at both ends of the inner mold 1 and the outer mold 2. Connection bolt 7 via packing 6
A spacer 9 is provided between the inner mold 1 and the outer mold 2 to maintain a predetermined gap between the winding 8 consisting of a cascaded connection of a plurality of block coils, for example, and the inner mold 1 and the outer mold 2. The outlet lead 13 is electrically connected to the embedded terminal fitting 4, and then the whole is heated and dried in vacuum, and a casting resin such as an epoxy resin composition containing an inorganic filler is poured under vacuum pressure. By molding, heating and curing the cast resin at a predetermined temperature, and releasing the mold, a resin molded winding integrally formed with an insulating layer 12 made of a cured cast resin is obtained. However, in the above-mentioned manufacturing method, the thickness of the mold insulating layer, especially the inner and outer insulating layers of the cylindrical winding wire, is required to withstand mechanical stress such as thermal stress applied to the insulating layer 12, so that the thickness is less than a certain level. However, it cannot be made very thin, resulting in increased winding weight and poor heat dissipation. In addition, since the interface between the spacer 9 for maintaining the thickness of the insulating layer 12 and the mold insulating layer 12 tends to peel off due to thermal stress, the spacer 9 is used to prevent this.
It is necessary to disperse and adhere a large number of extremely small spacers made of co-resin with the same composition as the casting resin onto the surface of the winding 8, and then store them in a casting mold. Bonding requires a large amount of man-hours and processing time. Furthermore, since the winding conductor 8 is supported in an unstable manner by the inner mold 1 and the outer mold 2 through the spacer 9, and complementary forces do not act sufficiently between the inner mold and the outer mold, the inner mold 1 and the outer mold Type 2
There are a number of problems, such as the need to form each mold strongly, which increases mold processing costs and requires a large space to store the inner mold 1 and outer mold 2.

[Purpose of the invention]

The present invention was made in view of the above-mentioned situation, and
A mechanically strong and thin insulating layer can be easily formed using a simplified mold that is easy to store.
Therefore, it is an object of the present invention to provide an economically advantageous method for manufacturing a resin molded winding wire.

[Summary of the Invention] The present invention provides an insulating layer on the inner circumferential side and the outer circumferential side of the winding wire by forming the cured product of a prepreg sheet laminate mechanically reinforced with a base material such as glass cloth. In addition to making it possible to form a thin insulating layer, a prepreg sheet layer is placed on the inside of the winding frame in close contact with the outside of the winding frame, which is to become the inner shape during casting.
An intermediate assembly consisting of a winding conductor, an outer prepreg sheet layer, and a thin iron plate is layered in order so as to be in close contact with each other based on the above-mentioned order, and after attaching an end mold and a terminal mold, a binding means provided on the terminal mold side is formed. By applying a binding force to the outer mold prepreg sheet layer through the outer mold, heating and hardening the prepreg sheet layer in the pre-drying process, and then performing casting and heating curing treatment of the casting resin, the prepreg It is possible to form an inner and outer circumferential insulating layer made of a cured sheet laminate that does not contain voids, and the structure of the casting mold can be simplified to one that is easy to store due to the complementary action of each part formed in layers. be.

[Embodiments of the invention]

The present invention will be explained below based on examples.

1 and 2 are structural diagrams for explaining an embodiment of the manufacturing method of the present invention, FIG. 1 is a sectional view in the axial direction, and FIG. 2 is a side view taken along the line A-A in FIG. 1. FIG. In the figure, reference numeral 21 denotes a winding frame that becomes the inner mold during casting, and in the figure, it is formed into a cylindrical shape made of a thin iron plate. Inner prepreg sheet layer 3 formed by coating and impregnating an epoxy resin containing an inorganic filler onto a base material such as cloth, and then winding a semi-cured prepreg sheet to a predetermined thickness.
form 1. Next, a plurality of block coils 8 made of, for example, a band-shaped coil conductor and an interlayer insulating material are wound one after the other on the outside of the prepreg sheet layer, and are connected in series to form a cylindrical winding 38. . Next, an outer prepreg sheet layer 3 having an opening 31A in close contact with the outer peripheral surface of the winding 38 is formed.
2 is formed in the same manner as the inner prepreg sheet layer 31. Next, an intermediate assembly is formed by attaching an outer mold 22 which is made of a flexible thin steel plate and has a connection part with a terminal mold at the end so as to be in close contact with the outside thereof. Next, the terminal mold 24 bent at a predetermined angle and equipped with the reinforcing plate 28 and the terminal fitting 4 is attached to the connection part of the outer mold 22 using the fastening screws 27, and sheet-like packing 6 and The end mold 5 is attached by a connecting bolt inserted through the hole 29, and the outer mold 22 is then secured by a binding means 30 consisting of a set screw 26 and a fastening screw 27 that are engaged with the terminal mold 24 and the end mold 5. A binding force is applied to the outer prepreg layer 32 through the assembly, thereby forming an assembly suitable for resin casting. It goes without saying that a mold release agent is applied to the mold release surface of the mold.

The assembly formed as described above is placed in a vacuum heating drying oven or the like and heated to dry. At this point, the semi-cured resin in the prepreg sheet layer is catalyzed and becomes fluid, making it difficult to roll. Line 8 or outer mold 32
prepreg sheet layer 3 with binding force applied by
The air bubbles in 1 and 32 are expelled from the layer together with the excess resin, and as the resin hardens, the inner insulating layer 31 and the outer insulating layer 32, which are made of a cured prepreg laminate without voids and fixed to the winding 38, are formed. can be formed. Next, the assembly is transferred to a casting tank, and the casting resin is vacuum-pressurized through the casting port 23 and the opening 31A, and the terminal fitting 4, the lead 13, the gap between the block coil 8, etc. is filled with casting resin 20, and a resin molded winding is formed through heat curing treatment, mold release, and cutting off of excess resin at the casting opening 23 portion.

According to the above manufacturing method, the intermediate assembly consisting of the inner mold 21, the inner prepreg layer 31, the winding 38, the outer prepreg layer 32, and the outer mold 22 is sequentially wound on a winding machine using the inner mold 21 as a winding frame. Each part is bonded to each other by a prepreg layer having appropriate adhesiveness and the shape of the intermediate assembly is maintained, making it extremely easy to attach end molds and terminal molds. , thus significantly simplifying the manufacturing process. Additionally, by increasing the morphological stability of the intermediate assembly, the outer mold 22 can be formed using a thin steel plate suitable for applying binding force to the outer prepreg layer 32, simplifying the casting mold. In addition, after the mold is released, the outer shape 22 can be expanded and stored as a plate-like body similar to the end mold 5, which has the advantage of saving space for storing the mold. Furthermore, by providing the binding means 30, the inner prepreg layer 31
Since heat curing treatment can be performed while applying a binding force to the outer prepreg layer 32, the inner and outer insulating layers 31 and 32 can be formed without voids and having excellent insulation performance and heat transfer performance. Can be done.

3 and 4 are explanatory diagrams showing different embodiments of the present invention, in which FIG. 3 is a sectional view in the axial direction, and FIG. 4 is a side sectional view in the BB direction of FIG. 3. In the embodiment shown in the figure, an insulating tube made of a laminated cured product of prepreg sheets formed in advance into a cylindrical shape is used on the winding frame 41 which is to serve as an inner mold during casting, and the prepreg sheets 1 to 1 are placed closely on the outside of the insulating tube. The manufacturing method is otherwise the same as in the previous embodiment. Therefore, the winding frame 41 doubles as the inner mold and also serves as the inner insulating layer of the resin molded winding, eliminating the need for the metal winding frame (inner mold) 21 in the previous embodiment, It is possible to further save space in the mold storage area. Further, by providing the thin prepreg layer 51, the winding frame 51 and the winding wire 38 can be fixed to each other through an insulating layer that does not contain voids, and therefore the inner insulating layer has excellent electrical insulation performance and heat transfer performance. 31 can be formed.

FIG. 5 is a side view showing an example of the resin molded winding wire after mold release. In the figure, the embedded terminals 4, pull-out leads 13, inter-coil connections 52, tap leads 53, tap terminals 54, etc., which are arranged intensively in one angular direction of the resin molded winding, are made of cast resin cured material. Embedded in the thick mold insulation layer 50 to maintain high insulation performance and mechanical strength,
In other angular directions, each block coil 8
The mutual gap 55 and end portion 56 are integrally formed by the molded insulating layer 20 and the thin insulating layers 31 and 32 whose inner and outer peripheral surfaces are reinforced with glass fiber or the like, thereby achieving high insulation performance. It is also possible to produce a resin-molded winding wire that has heat transfer performance and good heat stress resistance.

Although each of the above-mentioned embodiments has been described with respect to an example in which the casting opening is provided on the embedded terminal side, it goes without saying that the manufacturing method of the present invention can also be applied to a case where the casting opening is provided on the end mold 5 side. There is no such thing.

〔Effect of the invention〕

As described above, the present invention has a cylindrical winding frame that becomes an inner mold during resin casting, an inner prepreg sheet layer, a plurality of block coil windings, an outer prepreg sheet layer, and a connecting portion with a terminal mold. An intermediate assembly is formed by sequentially wrapping outer molds made of thin iron plates in layers based on the above-mentioned order, and an end mold is attached to the axial end through a sheet-like packing, and a terminal mold is attached to the connecting part. After the terminal mold was attached, a binding force was applied to the outer prepreg sheet layer through the binding means provided on the terminal mold side, thereby forming an assembly suitable for resin casting. As a result, the step of attaching the spacer and the step of assembling it into the inner and outer molds in the conventional method are eliminated, and the intermediate assembly can be easily formed on the winding machine.
In addition, each member is bonded to each other by a prepreg sheet layer having appropriate adhesiveness to form an intermediate assembly with good form stability, making it possible to easily attach the end mold and the terminal mold. Therefore, it is possible to provide a method for manufacturing a resin molded winding wire that is simplified and labor-saving.

Additionally, by improving the form stability of the intermediate assembly, the outer mold can be formed from a thin steel plate.
After the mold is released, it can be stored as a plate like the end mold, and the winding frame can be constructed using an insulating tube that serves as the inner insulating layer, simplifying the casting mold and saving storage space. It is possible to provide a method for manufacturing a resin mode winding wire that can save space.

Furthermore, the inner and outer insulation layers are reinforced with glass fibers and are formed from cured prepreg laminates that are bound to eliminate voids, which eliminates problems with conventional molded insulation layers that include spacers. The generation of cracks due to accumulated thermal stress is prevented, and the thickness of the insulating layer can therefore be reduced, contributing to providing a lightweight resin-molded winding with excellent insulation performance and cooling performance.

[Brief explanation of the drawing]

1 and 2 are axial sectional views and side sectional views for explaining embodiments of the present invention, and FIGS. 3 and 4 are axial sectional views for explaining different embodiments of the present invention. FIG. 5 is a side sectional view showing an example of a resin molded winding according to the present invention, and FIGS. 6 and 7 are an external view and an axial sectional view for explaining the conventional method. 1...Inner mold, 2,22...Outer mold, 3,23...
Casting port, 4... Embedded terminal fitting, 5... End mold, 6
... Packing, 7 ... Connection bolt, 8 ... Block coil, 9 ... Spacer, 10, 11, 1
2, 20, 50...Mold insulating layer, 13...Output lead, 20...Casting resin, 21...Reeling frame (also used as inner mold), 22...Outer mold, 24...Terminal mold, 2
6... Push screw, 27... Fastening screw, 28... Reinforcement plate, 30... Binding means, 31... Inner insulating layer (prepreg sheet layer), 31A... Opening, 32
...Outer insulating layer (prepreg sheet layer), 38...
... Winding wire, 41 ... Winding frame (insulating cylinder), 51 ... Thin prepreg sheet layer.

Claims (1)

[Scope of Claims] 1. An inner prepreg sheet layer on the outside of a cylindrical winding frame that becomes an inner mold during resin casting, a winding consisting of a cascaded connection of a plurality of block coils, and an angular direction facing the embedded terminal. An outer prepreg sheet layer having an opening at the top and an outer mold made of a thin iron plate having a connecting part with the terminal mold in the angular direction are sequentially wound in layers based on the above order to form an intermediate assembly. An end mold is connected to both axial ends of the frame and the outer mold, and a terminal mold is airtightly connected to the connecting portion through packing, and the outer peripheral mold is connected to the outer mold by means of binding means provided on the terminal mold side. A method of manufacturing a resin molded winding wire, which comprises applying a binding force to an outer prepreg sheet layer to form an assembly, and subjecting this assembly to heat drying, resin casting, and heat curing treatment. 2. In the method described in claim 1,
A resin characterized in that a cylindrical winding frame is formed in advance into a cylindrical shape of predetermined dimensions as a prepreg sheet laminated cured product, and this winding frame also serves as at least a part of the inner insulating layer of the resin molded winding. Method of manufacturing molded winding. 3 In what is stated in claim 1,
A method for manufacturing a resin molded winding wire, characterized in that the binding means is a push screw that engages with an end mold and a terminal mold, or a fastening screw that engages with a terminal mold and an outer peripheral mold.