JPS6328020A - Manufacture of insulating coil - Google Patents

Abstract

PURPOSE:To eliminate the production of carbon or the like which reduces an electric insulation and to obviate a shortcircuit between wirings and the deterioration of the insulation by winding an insulating wire on a conductor to form a coil, dipping the coil in a solvent to dissolve to remove a soluble binder resin, heat treating it and then impregnating it with solution of insulative resin or insulative resin and inorganic material. CONSTITUTION:An insulating wires 5 are wound on a bobbin 6 to form a coil 7. Then, the coil 7 is dipped in a good solvent of a soluble binder resin to dissolve to remove the resin. Then, it is heat treated in vacuum inert high temperature atmosphere. Then, the coil 7 is impregnated with solution of insulative resin or insulative resin and inorganic material. After impregnating, it is heated to approx. 100-150 deg.C to remove the solvent, then heated to the curing temperature of the resin to cure the resin. Thus, no carbon for reducing the electric insulation is generated in the heat treating step. And, a shortcircuit between wirings or the deterioration of the insulation do not occur due to mechanical vibration or impact.

Description

[Detailed Description of the Invention] rIJi Industrial Application Fields This invention relates to insulated coils that are heat-treated at high temperatures after winding and then used at relatively low temperatures, such as superconducting coils that generate intermetallic compounds through high-temperature heat treatment. The present invention relates to a method for manufacturing core wire coils for materials and coils using amorphous iron cores that require heat treatment at high temperatures.

"Conventional technology and its problems" Conventionally, insulated coils that are heat-treated at such high temperatures have been made by coating an inorganic insulator such as enamel frit on a conductor and heating it to form a ceramic insulating layer. A coiled insulated wire is known.

However, since the conductor and ceramic insulation layer of these wires are in close contact with each other, they do not have sufficient tearability as an insulated wire, and there is a chance that the insulation layer will crack when being wound around a coil. Since the coefficient of thermal expansion is different from that of the ceramic insulating layer, there is a problem in that strain is accumulated in the ceramic layer due to heat shock during heat treatment, and the ceramic layer is likely to peel off.

In order to improve this problem, inorganic fibers such as glass fibers are fixed onto the conductor using binder resin, then heated to harden the binder resin to form an insulated wire, and this insulated TFi wire is wrapped around a bobbin etc. Later,
Coils are known that are heated to high temperatures in the air to decompose and eliminate the binder resin, thereby making the inorganic fibers look like the inorganic fibers, almost eliminating the adhesion between the conductor and the inorganic fibers, and providing sufficient heat resistance. It is being

However, in this insulated coil, the conductor and bobbin are oxidized at the same time when the binder resin is thermally decomposed, so the conductor and bobbin must be made of materials with good oxidation resistance. The disadvantage was that it was limited in scope.

For this reason, the present inventors first provided an insulating layer made of inorganic fibers and a soluble binder resin on a conductor to make an insulated wire, then wrapped this insulated wire to make a coil, and created a coil made of a soluble binder resin. We proposed a method for manufacturing insulated coils in which the soluble binder resin is dissolved and removed by immersion in a solvent. Although this method solves the above problem, since the wires of the coil are not connected to each other, when used near room temperature, the wires tend to move due to temperature changes, vibrations, etc., and the characteristics of the coil change. There was a problem.

[Means for Solving the Problems] Therefore, in the present invention, an insulated wire having an insulating layer made of inorganic fibers and a soluble binder resin formed on a conductor, or an insulated wire made of inorganic particles and a soluble binder resin formed on a conductor. An insulated wire having a first insulating layer, a second insulating layer made of inorganic fibers, and a soluble binder resin is wound to form a coil, and the coil is immersed in a good solvent for the soluble binder resin to dissolve and remove the soluble binder resin. Then, after heat treatment in an inert atmosphere, the above-mentioned problem was solved by impregnating with an insulating resin or a solution consisting of an insulating resin and an inorganic substance.

Figure 1 shows the first insulated wire used in this invention.
An example is shown in which the symbol t in the figure is a conductor. The conductor l is not particularly limited, and is particularly preferably made of a material with poor oxidation resistance at high temperatures, such as copper, copper alloy, or superconducting wire whose surface is coated with these metals. The diameter of the conductor l is approximately 0°1 to 5 mm, but is not limited to this.

An insulating layer 2 is provided on the surface of this conductor 1. This insulating color 2 is obtained by coating and impregnating an inorganic fiber with a resin liquid consisting of a soluble binder resin while tightly winding it in a spiral shape on a conductor l, and then heating the inorganic fiber at a temperature below the curing temperature of the soluble binder resin to volatilize the solvent. This is an inorganic ta vertebra fixed to a conductor l. Examples of inorganic fibers include single fibers such as electrical glass fibers, alumina fibers, zirconia fibers, and silica fibers, as well as twisted threads, aligned threads, and
Woven tape is used. The soluble binder resin may be any resin as long as it is easily soluble in water or organic solvents, but in the unlikely event that a small amount remains, resins that easily decompose and disappear as monomers, such as methacrylic esters, may be used. Polymers, acrylic acid ester polymers, copolymers thereof, and polyethylene oxide which is soluble in both water and organic solvents are desirable. This resin liquid has a concentration of 05 to 10 in which these resins are dissolved.
About % by weight is used. In addition, the heating temperature is water,
The temperature is good as long as the organic solvent volatilizes, and when a thermosetting resin is used as the soluble binder resin, it is necessary to maintain the temperature lower than the crosslinking temperature thereof.

The thickness of this insulating layer 2 is usually about 5 to 500 μm. Furthermore, the proportion of inorganic m fibers in the insulating layer 2 is ff1f
It is preferable that the fi ratio is 60 to 99.5% and that the amount of soluble binder resin is as small as possible.

A lubricating layer is provided on this insulating layer 2 if necessary. This lubricant B1 is used to improve surface slippage and workability when the insulated wire is wound into a coil, and is formed by applying a soluble wax.

FIG. 2 shows the second insulated wire used in this invention.
This is an example. This insulated wire is a conductor! First, a first layer consisting of inorganic particles and a soluble binder resin is placed on top.
An A-edge layer 3 is provided. As the inorganic particles, powders of alumina, silica, zirconia, glass, etc. having an average particle size of 0.1 to 10 μm are used. Moreover, as the soluble binder resin, the same one as mentioned above is used. The concentration of this soluble binder resin is 0.5 to 40% by weight.
A dispersion liquid is prepared by adding inorganic particles to a resin liquid, this dispersion liquid is applied to the conductor 1, and heated at a temperature below the curing temperature of the soluble binder resin to make it adhere to the conductor 1 to form the first insulating layer 3. The thickness of the first insulating layer 3 is usually 0.5 to 50 μm, and the proportion of inorganic particles is 70 to 99.5% by weight.

A second insulating layer 4 made of inorganic fibers and a soluble binder resin is provided on the first insulating layer 3. This second
The insulating layer 4 is similar to the insulating layer 2 of the insulated wire in the previous example, and has a thickness of about 5 to 500 μm.

Next, a method for manufacturing an insulated coil using such an insulated wire 5 will be described.

First, the wire 5 is wound around a bobbin 6 as shown in FIG. 3, for example, to form a coil 7. Next, the coil 7 is immersed in a good solvent for the soluble binder resin to dissolve and remove the soluble binder resin.

If the insulated wire 5 is coated with a lubricant layer, the lubricant layer is removed by immersing it in a solvent that dissolves the lubricant forming the lubricant layer. If the lubricant and soluble binder resin are soluble in the same solvent, they can be dissolved and removed at the same time.

As the above-mentioned good solvent, water, ketones, esters, alcohols, hydrocarbons, halogenated hydrocarbons, etc. are appropriately selected in combination with the soluble binder resin. The resin may be heated to a certain degree to promote dissolution of the resin. When specifically dissolving the soluble binder resin, it is preferable to change the solvent several times.

By this solvent immersion, the insulation layer 2 of the insulated wire 5 or the first
The soluble binder resin of the insulating layer 3 and the second insulating layer 4 is dissolved and removed, and these insulating F! J2.3.4 is formed from inorganic particles and inorganic fibers having good heat-resistant insulation properties, and this insulated coil 7 has extremely high heat resistance.

The insulated coil 7 thus obtained is then heat treated in an inert high temperature atmosphere of inert gas or vacuum. This heat treatment heats the conductor 1 to generate intermetallic compounds in the conductor metal, or to generate a phase change in the metal forming the bobbin or iron core. This is necessary for use in Heat treatment is performed at 500-900°C for 1-50°C under vacuum or in an inert gas such as nitrogen or argon.
This is done by heating for about an hour.

In this heat treatment, since all of the insulating layers 2.3.4 are made of inorganic materials, the insulating properties of the coil 7 are not changed.

Next, as shown in FIG. 4, the heat-treated insulated coil 7 is impregnated with an insulating resin or a solution consisting of an insulating resin and an inorganic substance. As the insulating resin, resins with good electrical insulation and heat resistance such as epoxy resins, silicone resins, and phenol resins are preferable, and solutions of these resins dissolved in organic solvents are used for impregnation. Inorganic powders such as insulating silica, alumina, and glass are used as the inorganic material. For the impregnation treatment, a conventional method such as vacuum impregnation treatment is used. After impregnation, the resin is heated to about 100 to 150°C to remove the solvent, and then heated to the curing temperature of the resin to harden the resin. In addition, when using an insulating resin and an inorganic substance, by setting the weight ratio of the insulating resin to the inorganic substance to 3/7 or less, it is possible to make the impregnated material made of the insulating resin and the inorganic substance porous. This makes it suitable for cooling the coil by infiltrating the inside of the coil with cooling gas or cooling liquid.

By this impregnation treatment, the wires of the coil are fixed with an insulating resin or an impregnated material 8 made of an insulating resin and an inorganic substance, thereby obtaining the desired insulated coil.

[Operation] According to this method of manufacturing an insulated coil, inorganic particles and inorganic fibers that do not stick to the conductor l are fixed to the conductor l using a soluble binder resin. Since the stone 2.3.4 does not peel off from the conductor l, and the surface of the insulation ff12.3.4 is relatively smooth and does not easily rub, there is no chance of the wires rubbing against each other or being scratched by the bobbin collar. There are no problems such as the fibers falling apart due to sharpening, and exhibits good processability. Furthermore, since the soluble binder resin is dissolved and removed before heat treatment, there is no generation of carbon or the like that degrades electrical insulation during the heat treatment process. In addition, since an impregnation treatment is performed after the heat treatment and the portion between the wires of the coil 7 is filled and solidified with resin or an impregnated material made of resin and inorganic material, short circuits between the wires and insulation deterioration due to mechanical vibrations and impacts are prevented. It never happens. Furthermore, since the heat treatment is performed in an inert atmosphere, materials that are susceptible to high-temperature oxidation can be used for the conductor and bobbin.

[Example 1] - A glass fiber with a diameter of 7 μm is spirally wound around the surface of a copper wire with a diameter of 1.5 mm, and a copolymer (glass transition A 30% toluene solution (temperature: 40°C) was applied and impregnated, and then the toluene was volatilized in a heating furnace at 150°C to form an insulating layer consisting of approximately 100 μm of glass fiber and acrylate copolymer, and an insulated wire was formed. Obtained.

Next, this insulated wire has a body diameter of 50 mm and an inner width of 150 mm.
A coil was created by winding a 10-layer pie filer around a ceramic-coated metal bobbin.

This coil was immersed in dichloromethane, which is a good solvent for acrylate copolymer, and when about two to three layers of resin of the coil were dissolved, the acrylate copolymer was dissolved and removed by replacing it with fresh dichloromethane. Then,
After heating this coil at 800° C. for 50 hours in a nitrogen atmosphere, the line-to-line insulation resistance at room temperature was measured and confirmed to be 108Ω or more. Next, this coil was impregnated with a 30% solution of epoxy resin in methyl ethyl ketone, the solvent was volatilized, and the resin was further cured by heating to obtain an insulated coil.

[Example 2] On the surface of a copper wire with a diameter of 1.5n++n, 75 parts by weight of inorganic particles of 50if% of alumina with an average particle size of 5 μm and 50t[f% of glass frit with a softening flow temperature of 700°C] and normal butylmethane were applied. A slurry prepared by dissolving and dispersing 25 parts by weight of a copolymer (glass transition temperature: 40°C) consisting of 50 parts of acrylate and 50 parts of iso-butyl acrylate in toluene is coated and dried, and the first insulating layer has a thickness of approximately 30 μm. has been established. Next, glass fibers of 7 μm diameter are spirally wound on this first insulating layer, and 50 parts of normal butyl methacrylate and 5 parts of iso-butyl acrylate are wrapped around the glass fibers.
30 parts of a copolymer (glass transition temperature 40°C) consisting of 0 parts
% toluene solution was applied and impregnated, and then the toluene was volatilized in a heating furnace at 150° C. to provide a second insulating color made of glass fiber and acrylate copolymer of about 100 μm.

Thereafter, the binder resin was removed and heat treated at the same tp as in Example 1, followed by impregnation treatment to obtain an insulated coil.

[Example 3] The coil after the heat treatment of Example 1 was vacuum impregnated with a dispersion in which 60fffflt parts of alumina particles with an average particle size of 0°5 μm and 40 parts by weight of Evokin resin were dissolved and dispersed in toluene to form an insulated coil. I got it.

[Example 4] The coil after the heat treatment of Example 2 was vacuum impregnated with a dispersion in which 60 parts by weight of alumina particles with an average particle diameter of 65 μm and 40 parts by weight of Evokin resin were dissolved and dispersed in toluene to obtain an insulating film. .

These four types of insulated coils have an acceleration of 9.8G and an amplitude of 2mm.
A vibration test was conducted 10 times each in two directions, vertical and horizontal, of the coil, and the insulation characteristics between the lines after the test curve were investigated.

For comparison, similar vibration tests were also conducted on the coils of Examples I and 2, which were not subjected to the impregnation treatment after the heat treatment. These results are shown in the attached table.

As is clear from this result, the insulated coils of Examples 1 to 4 have excellent vibration resistance characteristics.

[Effects of the Invention] As explained above, the method for manufacturing an insulated coil of the present invention is based on an insulated wire in which an insulating layer made of inorganic fibers and a soluble binder resin is formed on a conductor, or an insulated wire in which an insulating layer made of inorganic fibers and a soluble binder resin is formed on a conductor. a first insulating layer consisting of and an inorganic m
An insulated wire with a second insulating layer formed of fibers and a soluble binder resin is wound to form a coil, the coil is immersed in a good solvent for the soluble binder resin to dissolve and remove the soluble binder resin, and then placed in an inert atmosphere. After heat treatment, it is impregnated with an insulating resin or a solution consisting of an insulating resin and an inorganic substance, so the soluble binder resin can be dissolved and removed before the heat treatment. will no longer be generated. In addition, since the coil is impregnated after heat treatment and filled with resin or resin and inorganic material between the wires of the coil, it will not cause short circuits between the wires or insulation deterioration due to mechanical vibration or impact. . Furthermore, since the heat treatment is performed in an inert atmosphere, it has the advantage that materials that are susceptible to high-temperature oxidation can be used for the conductor and bobbin.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing a first example of an insulated wire used in this invention, FIG. 2 is a schematic sectional view showing a second example of an insulated wire used in this invention, and FIGS. FIG. 4 is a partial cross-sectional view showing an example of the method for manufacturing an insulated coil according to the present invention in the order of steps. l...Conductor, 2...Insulating layer, 3...
...First insulating layer, 4... Second insulating layer, 5...
...Insulated wire, 7...Insulated coil, 8...
・・Impregnated material－〇

Claims (2)

[Claims] (1) An insulated wire with an insulating layer made of inorganic fibers and soluble binder resin formed on a conductor is wound to form a coil, and the coil is immersed in a good solvent for soluble binder resin to dissolve and remove the soluble binder resin, A method for manufacturing an insulated coil, which is characterized in that the coil is then heat treated in an inert atmosphere and then impregnated with an insulating resin or a solution consisting of an insulating resin and an inorganic substance. (2) An insulated wire having a first insulating layer made of inorganic particles and soluble binder resin and a second insulating layer made of inorganic fibers and soluble binder resin formed on a conductor is wound to form a coil, and this coil is made into a soluble An insulated coil characterized by being immersed in a good solvent for a binder resin to dissolve and remove the soluble binder resin, then heat-treated in an inert atmosphere, and then impregnated with an insulating resin or a solution consisting of an insulating resin and an inorganic substance. Manufacturing method.