JPS6243533B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coil insulation treatment method. More specifically, the present invention relates to a method for insulating a coil that is simple to insulate and provides a high-performance insulated coil.

Electromagnetic coils are components that are always used in electrical equipment products, and their electrical insulation ranges from simple ones to those that require strict characteristics.

Simple electromagnetic coils often have some type of protective insulation, generally taping, to isolate the coil from the outside so that the copper wire insulation will not be damaged. Insulation between the coil wires ranges from those that require only copper wire insulation, to those that compensate for damage and defects by winding, and those that require insulation between the coil wires by dipping them in insulating varnish to prevent electromagnetic vibration between the wires. There are some things that make it stick.

In addition, for electromagnetic coils that require strict characteristics, it is necessary to insulate the entire electromagnetic coil from the outside, or
Alternatively, a method is adopted in which the electromagnetic coil wires are insulated from each other. Generally, in the former method, insulating materials include film materials, tape materials, putty materials, dipping materials, casting materials, molding materials [including bulk molding compound (BMC), sheet molding compound (SMC)], etc. is used, and in the latter method an impregnating agent is usually used.

Transparent resins are generally used as impregnation materials, such as solvent-free epoxy resins, unsaturated polyester resins,
Impregnation resins such as polyurethane resins, silicone resins, and polyimide resins are used. The properties necessary for the impregnating resin are low viscosity, easy impregnation, and long pot life.The processing methods for the impregnating resin range from those used only by immersion to those using vacuum impregnation using a mold.

Further, as the copper wire to be insulated, enamelled wire, glass-wound wire, paper-wound wire, etc. are used.

However, to form these insulators, there are many processes, such as vacuum impregnation using a mold and casting resin after curing, and methods that require only insulation using insulated copper wire. Although various methods have been adopted, it is almost impossible to obtain a completely insulated electromagnetic coil using any of the insulation treatment methods. Particularly, impregnation treatment methods that do not use a mold have the disadvantage that the viscosity of the impregnated resin decreases during curing and flows out from within the electromagnetic coil. In order to prevent the impregnated resin from flowing out from inside the electromagnetic coil,
Insulating treatment methods such as using ultraviolet curable resin as the impregnating resin, catalyst separation method in which the resin curing catalyst is not put in the resin but in the impregnated material, and rotary drying method are being considered, but these methods are not yet sufficient. However, the resulting electromagnetic coil has some internal voids and poor impregnation.

The present inventor has completed the present invention as a result of intensive research to provide a method for insulating coils that eliminates the above-mentioned drawbacks, provides simple insulation work, and provides high-performance insulated coils. Ivy.

That is, in the present invention, the electromagnetic coil is electrically heated and the surface of the coil is coated to a thickness using a fluidized dip coating method.
A method for insulating a coil, which comprises forming a powder coating film having a thickness of 0.1 to 10 mm, vacuum-impregnating it with a solvent-free impregnating resin, and then curing the impregnating resin while rotating. Therefore, by applying the above-mentioned specific insulation treatment method to the insulation of the electromagnetic coil, the impregnated resin may flow out from the inside of the electromagnetic coil when the impregnated resin is cured, as in the conventional method, and the curing process operation is complicated. The above-mentioned drawbacks are eliminated, and even if the viscosity of the impregnated resin decreases due to temperature rise, the coil wire is sufficiently insulated without the impregnated resin flowing out from inside the electromagnetic coil, and the curing process is easy. However, the very remarkable effect that a high-performance insulated coil can be obtained is achieved.

In the method of the present invention, the first step is to heat the electromagnetic coil and apply powder coating, the second step is to vacuum-impregnate the electromagnetic coil with a solvent-free impregnating resin, and immediately after vacuum-impregnating, the electromagnetic coil is placed on a rotary curing table and rotated. However, the objective is achieved by the third step of curing the solvent-free impregnated resin by heating using a conventional method.

In the method of the present invention, electric heating is used to heat the electromagnetic coil to be powder coated, which can heat only the coil to be insulated.

In general, electromagnetic coils are either a single coil such as a coil of insulated wire or a winding frame (i.e. bobbin).
It is usually wound around an insulated iron core.

The heated electromagnetic coil is coated using the fluidized dipping method, and a coating film with a thickness of 0.1 to 10 mm is formed on the coil surface. The coating film formed may be either semi-cured or cured. Incidentally, by applying powder coating while heating the electromagnetic coil and fluidizing it, a coating film is easily formed, and the coating time is significantly shortened. The coating film formed serves as an insulator between the coil and the outside.

Examples of the powder coating used in the method of the present invention include powder coatings such as polyethylene, vinyl chloride resin, acrylic resin, polyester resin, and epoxy resin. Among those powder coatings,
It is preferable to use an epoxy powder coating because it enables rapid curing of the coating film and provides a coating film with excellent electrical and mechanical properties. In addition, the thickness of the coating film formed on the coil surface of the electromagnetic coil is 0.1 to 10 mm, which prevents external influences in the usage environment and allows the electromagnetic insulated coil to be completely insulated from the outside. available.
If the thickness of the coating film is greater than 10 mm, there is a risk that the coating film will sag when the impregnated resin hardens, damaging the appearance of the resulting insulated coil and forming pinholes. On the other hand, when the diameter is smaller than 0.1 mm, the coating film is thin and many pinholes are formed, which is not preferable.

In the method of the present invention, the electromagnetic coil on which the coating film has been formed is placed in a vacuum impregnation tank, and after the impregnation tank is evacuated, a solvent-free impregnating resin is injected into the electromagnetic coil, completely filling the coil. is filled with. In this case, in the case of a coil wound around an iron core, the solvent-free impregnating resin enters into the coil through pinholes in the coating film or the interface between the iron core and the coil. If the coating film formed on the coil surface prevents the solvent-free impregnating resin from entering the coil, it is necessary to prevent the solvent-free impregnating resin that has entered the coil from flowing out from the coil during rotational curing, which will be described later. Then, small holes are made in the coating at suitable locations. Preferably, the small holes are provided inside the coil to be rotationally hardened, close to the rotational axis.

Examples of the solvent-free impregnating resin used in the method of the present invention include epoxy resins, unsaturated polyester resins, silicone resins, and polyurethane resins.

Next, the electromagnetic coil vacuum-impregnated with the solvent-free impregnated resin is immediately placed on a rotary curing table, and while the coil is being rotated, the impregnated resin impregnated into the coil is heated and cured by a conventional method.

The rotation speed of the electromagnetic coil is circumferential speed 5~
100m/min is adopted, which prevents the solvent-free impregnated resin impregnated into the coil from flowing out due to its own weight, and prevents it from sputtering in the circumferential direction, allowing the impregnated resin to completely harden within the coil. It will be done. When the rotation speed is higher than 100 m/min, the solvent-free impregnated resin in the coil scatters toward the outer circumferential direction of the rotation, and when the circumferential speed is 5 m/min,
When it is smaller than min, the solvent-free impregnated resin flows out from the coil due to its own weight, which is not preferable. As a coil for rotationally curing impregnated resin,
It is also preferable to have a coil wound around the stator of a rotating machine. This is because slot insulation is provided in the iron core in the outflow direction when the impregnated resin flows out to the outside, so no outflow of the impregnated resin occurs.

In the method of the present invention, a powder coating film is formed on the surface of the electromagnetic coil by a fluidized dipping method while heating the electromagnetic coil. Therefore, the coating film can be easily formed in a short time, and this coating film can be easily formed. In addition to preventing the solvent-free impregnated resin impregnated into the coil from flowing out,
It is effective in insulating the coil from the outside, and the solvent-free impregnated resin inside the coil is cured when completely filled inside the coil, which serves to insulate between the coil wires and prevent vibrations, which improves performance. An extremely excellent edge coil can be obtained.

The method of the present invention is suitable for insulating magnetic coils, field coils, underwater motors, etc. in addition to insulating electromagnetic coils.

Next, the coil insulation treatment method of the present invention will be described with reference to examples.

Example 1 Magnet wire (diameter: 1
We will discuss the stator insulation of a corrosion-proof motor that is wound loosely (the slots are insulated with polyethylene terephthalate film).

First, a 3-phase 200V current was applied for 20 seconds to bring the temperature of the coil to approximately 200℃, and the coil was coated with epoxy powder paint [manufactured by Ryoden Kasei Co., Ltd., product name VEP46-2] by the fluidized dipping method. A coating film having a thickness of 1 to 3 mm was formed on the surface. Next, this coil was placed in a vacuum impregnation tank, and 100 parts (by weight, the same shall apply hereinafter) of a solvent-free epoxy resin [Epicote 815 (epoxy resin manufactured by Ciel Chemical Co., Ltd.), methylnadzic acid anhydride (80 parts), and benzyldimethylamine ( Part 1)
After vacuum impregnating with a solvent-free epoxy resin consisting of the following materials, the material was immediately placed on a rotary curing table and rotary hardened for approximately 3 hours in a hot air circulation oven at 150° C. at a circumferential coil speed of 20 m/min.

The interior of the obtained stator was completely filled with cured resin. Furthermore, the obtained stator exhibited an insulation resistance of 1×10 ¹² Ω or more in water, and there was almost no decrease in MEG when left in water.

As mentioned above, in the method of the present invention,
The insulation work is simple and a high-performance insulation coil can be obtained, which is extremely advantageous industrially.

Claims (1)

[Scope of Claims] 1. A powder coating film having a thickness of 0.1 to 10 mm is formed on the surface of the electromagnetic coil by a fluidized dip coating method while being heated with electricity, and then vacuum impregnated with a solvent-free impregnation resin. A method for insulating a coil, comprising: curing the impregnated resin while rotating the coil. 2. The coil insulation treatment method according to claim 1, wherein the solvent-free impregnating resin is an unsaturated polyester resin, an epoxy resin, a silicone resin, or a polyurethane resin. 3 Immediately after vacuum impregnation, the resin is placed on a rotary curing table and heated while rotating at a circumferential speed of 5 to 100 m/min to cure the impregnated solvent-free impregnated resin and the coating film, as claimed in claim 1. The described coil insulation treatment method.