JPS62133611A - Manufacture of insulated wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an insulated wire useful as, for example, a winding wire for a high frequency transformer.

Conventional technology and problems that need to be solved As winding wires for high-frequency traverses, conventional twisted and knotted wires,
Twisted enamelled wire is used.

These windings are made by applying ordinary insulating varnish onto the conductor and baking it. It has a structure in which a large number of so-called enamelled wires are assembled (twisted, etc.) and then fibers or tape are wrapped on top of them to provide an external insulating layer.

By the way, the above-mentioned winding wire has a problem that the finished outer diameter is large because the outer insulating layer has a structure such as fiber-wrapped or tape-wound, and there is also a large amount of air remaining inside the stranded wire. There is also the problem of poor heat dissipation.

In order to solve the above problems, the present inventors.

We tried a method of applying ordinary insulating varnish to the strands of enamelled wire and filling the gaps between the strands with varnish resin, but we found that the gaps between the strands were large and that ordinary insulating varnish requires a large amount of resin. Due to the presence of organic solvents in the varnish, a problem occurred in which the applied varnish foamed when baked after application.

SUMMARY OF THE INVENTION The present invention overcomes the above problems by using a highly concentrated varnish to fill the voids between the strands.

That is, the present invention is characterized in that a high concentration varnish with a resin concentration of at least 40% by weight is coated and baked on an assembly consisting of a large number of enameled insulated wires, and then an insulating varnish is further coated and baked thereon. The present invention provides a method for manufacturing an insulated wire.

A highly concentrated varnish having a working resin concentration of at least 40 ft/w is applied to the assembly using a conventional die, thereby filling the voids within the assembly with the varnish. During the subsequent baking, the organic solvent in the varnish is removed, but because of the high concentration of the varnish, the amount of organic solvent removed is small and therefore foaming does not actually occur.

According to experiments conducted by the present inventors, coating films formed by applying and baking high-concentration varnishes such as those used in the present invention are generally brittle;
Therefore, it tends to peel off easily.

However, in the present invention, after applying and baking a high concentration varnish, a normal insulating varnish is applied on top of it.
Since the external insulating layer is formed by baking, problems such as peeling do not occur. Furthermore, since the external insulating layer is formed by coating and baking, it is a much thinner layer than that of conventional products.

The enamel insulated wire used in the present invention includes:
Metal conductors of circular, square or other shapes in cross-section (e.g. copper wire, aluminum wire, copper-clad aluminum wire, copper-plated iron wire, iron wire).

etc.) by applying and baking an insulating varnish on top. That is,
What is commonly known as magnet wire, such as formal wire, polyester wire.

Polyesterimide wire, polyamideimide wire, polyimide wire, oil-based enameled wire, polyamide wire, etc. are used. In addition to single-layer insulation as described above, the enamel insulated wire may also have two or more multilayer insulation layers formed using two or more types of insulating varnish. may exist. In the present invention.

A total of two or more pieces of one or more types of enamel insulated wire,
For example, 3 to 10 pieces may be twisted together into a round, square, or other shape in cross section.

A high concentration varnish is applied on the collecting lines, and this high concentration varnish has a resin content of at least 40% by weight.
are used. If the resin content is less than 40% by weight, foaming tends to occur during the baking process after coating. Generally, the higher the resin content, the more difficult it is to cause foaming, but if the concentration is too high, the varnish viscosity will increase, making it difficult to apply.

In addition, the ability to fill voids in the assembled wires is reduced.

Therefore, the preferred resin content in the varnish is 43 to 70
% by weight, especially from 45 to 60% by weight (note that if polymerizable monomers, such as styrene used in unsaturated polyester varnishes, are required, their usage is included in the above weight % figures). do not have.).

The resin content contained in high concentration varnish is alkyd,
Thermosetting materials such as unsaturated polyester, silicone, and epoxy are preferable, and the solvent for these resins is preferably a parent solvent with a boiling point of 180° C. or less. Commercially available varnishes are used as impregnating varnishes for electrical equipment coils.

For example, N-265, Nv-5544 manufactured by Tokyo Denko Corporation
, Eclipse Schenectaday's Isonel 51, Isonel 31, etc. can be used. The solvent used may have a high boiling point.

Generally, when a high boiling point material is used, it is necessary to bake at a low temperature for a long time to prevent foaming.

For this reason, those with low boiling points as described above are preferably used. Further, the resin contained in the varnish may be thermoplastic, but as they generally have poor heat resistance, thermosetting resins are preferred as described above. Note that when a thermosetting resin varnish is used, depending on the type of resin, the assembled lines may become excessively rigid when completely cured.

In such cases, it is advisable to bake the resin to a semi-hardened state.

The semi-cured resin may be completely cured by winding the insulated wire of the present invention around the coil of a high-frequency transformer and then heating it, or it may be completely cured naturally by the heat generated when the coil is used. Good too. Furthermore, an inorganic filler may be added to the above resin as necessary.

In the present invention, after applying and baking the above-mentioned high concentration varnish, a normal insulating varnish, that is, the above-mentioned magnetic varnish is applied.
Varnishes used in the manufacture of l-wires, e.g.
One or more of formal varnish, polyamide varnish, polyester varnish, polyester imide varnish, polyamide imide varnish, polyimide varnish, etc. is applied and baked. These insulating varnishes generally have a resin concentration of 4
The concentration is low, less than 0% by weight, so the baked layer is tough and flex resistant. Particularly preferred insulating varnishes are polyimide varnishes such as di-polyamide-imide varnish and polyimide varnish, and formal varnishes. The baking N of those varnishes is.

It has good flexibility. Further, if necessary, a self-fusion layer may be further provided on the baked layer of the insulating varnish.

Effects The insulated wire of the present invention has excellent heat dissipation properties because the gaps between the assembled wires are sufficiently filled by applying and baking a high degree varnish. Since the insulated wire is formed into an extremely thin layer, the finished outer diameter of the insulated wire of the present invention is considerably smaller than that of conventional products.

Therefore, by using the insulation wire of the present invention, it is possible to downsize the transformer.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example-1 Seven strands of 1.0 fi type 1 polyester imide copper wire were core-twisted, and Isonel 51 manufactured by Schenectaday Co., Ltd. was applied and baked three times to obtain a film with an apparent thickness of about 25 μm, Furthermore, polyamide-imide varnish (manufactured by Hitachi Chemical Co., Ltd., HI405) was applied four times, and the apparent thickness of the upper layer was approximately 5 mm.
An insulated strand of 0 μm was obtained. The characteristics of this are shown in Table 2.

Example-2 1. ON type 1 polyamide-imide overcoated polyester-imide copper wire was twisted between 7 cores, and NV-5544 varnish manufactured by Nitto Denko Corporation was applied and baked three times to give a good appearance.
A 30 μm film was obtained, and then polyvinyl formal varnish was applied twice on top.

Polyamide-imide varnish (manufactured by Hitachi Chemical Co., Ltd., H1405)
) was applied and baked twice, and the apparent thickness of the upper layer was approximately 50 μm.
An insulated strand of wire was obtained. Its properties are shown in Table r.

Comparative Example-1 1. Polyamide-imide varnish (manufactured by Hitachi Chemical Co., Ltd., HI
405) was coated and baked three times in an attempt to obtain an insulated stranded wire with an apparent film thickness of 15 μm, but foaming occurred over the entire surface of the film and a good product could not be obtained.

Comparative Example-2 Seven strands of 1.0 Tsuru type 1 polyester copper wire were core-twisted, and NV-5544 manufactured by Nitto Denko Corporation was coated and baked 8 times.
An insulated stranded wire with an apparent coating thickness of 50 μm was obtained. Its properties are shown in Table 1, and it had low resistance to one bend and was mechanically brittle.

Example-3 Eight 0.55 m type 1 polyamide-imide copper wires were formed into a flat shape and twisted to obtain a flat stranded wire with an apparent size of 1.2 x 2.4 mm.Isonel 51 manufactured by Japanese-German Skanektady Co., Ltd. was applied to this. The wire was coated and baked four times, and poly7imide varnish (manufactured by Hitachi Chemical Co., Ltd., H1405) was further coated and baked four times to obtain an insulated rectangular shaped stranded wire with a good appearance.

Note: Bendability: Visually check the condition of the upper layer when bent around a metal rod with a diameter of 6 squares.

Abrasion resistance: JIS C3003-1976 10.1
The value at a load of 700 g was determined according to the section.

Claims (1)

[Claims] 1. Applying and baking a high-concentration varnish with a resin concentration of at least 40% by weight to an assembly consisting of a large number of enameled insulated wires, and then further applying and baking an insulating varnish thereon. A method for manufacturing an insulated wire characterized by: 2. The method for manufacturing an insulated wire according to claim 1, wherein the high concentration varnish is obtained by dissolving a thermosetting resin in an organic solvent having a boiling point of 180° C. or lower. 3. The concentration of resin in the high concentration varnish is 45 to 60% by weight
A method for manufacturing an insulated wire according to claims 1 and 2. 4. The method for manufacturing an insulated wire according to claims 1 to 3, wherein the insulating varnish is a polyimide varnish or a formal varnish.