JPS6259453B2 - - 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, which is simple to insulate and can provide a high-performance insulated coil.

Electromagnetic coils are components that are always used in electrical equipment products, and their electrical insulation ranges widely from simple to demanding properties.

In simple electromagnetic coils, some type of protective insulation, generally taping, is used to isolate the coil from the outside so that the insulation of the copper wire or aluminum wire (hereinafter, aluminum wire is omitted) is not damaged. There are many things. In addition, insulation between wires in electromagnetic coils ranges from those that require only copper wire insulation to those that compensate for damage and defects through winding processing.
In order to prevent electromagnetic vibration between the wires, some coil wires are dipped in insulating varnish to fix the coil wires together.

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

Generally, transparent resins are used as the impregnating material, and impregnating resins such as solvent-free epoxy resins, unsaturated polyester resins, 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 types of impregnating resins range from those used only for immersion to those used for vacuum impregnation using a mold.

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

However, in order to form these insulating structures, there are many work steps such as vacuum impregnation using a mold and casting resin after hardening. A variety of methods have been adopted, including one that involves only taping, but with any of these insulation treatment methods, it is almost impossible to obtain a sufficiently insulated electromagnetic coil, and the workability is not always sufficient. In particular, an impregnation treatment method that does not use a mold has the disadvantage that the impregnated resin decreases in viscosity during curing and flows out from the electromagnetic coil. In order to prevent the impregnated resin from leaking out of the electromagnetic coil, we use ultraviolet curing resin as the impregnating resin, a catalyst separation method that integrates the resin and the curing agent or catalyst separately, and a rotary curing method. Although insulation treatment methods have been studied, they are not yet satisfactory, and the resulting electromagnetic coils often have gaps or poor impregnation.

The present inventor has conducted extensive research in order to eliminate the above-mentioned drawbacks, provide a method for insulating a coil that is simple to insulate, and can provide a high-performance insulated coil, and as a result has completed the present invention. It was it.

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.
The method relates to a method for insulating a coil, which comprises forming a powder coating film having a thickness of 0.1 to 10 mm, then vacuum impregnating it with a solvent-free impregnating resin having thixotropic properties at room temperature, and then curing it. By applying the above-mentioned specific insulation treatment method to the insulation of the electromagnetic coil, the impregnated resin may flow out from inside the electromagnetic coil when the impregnated resin is cured, as in the conventional method, and the curing operation is complicated. The above-mentioned drawbacks have been eliminated, and even if the viscosity of the impregnated resin decreases due to temperature rise, the impregnated resin will not flow out of the electromagnetic coil and the coil wires will be sufficiently insulated, making the curing process easy. However, the very remarkable effect that a high-performance insulated coil can be obtained is achieved.

In the method of the present invention, a first step of heating an electromagnetic coil to apply powder coating, a second step of vacuum impregnation with a solvent-free impregnating resin having thixotropic properties, and a third step of curing the impregnated resin achieve the desired purpose. can be achieved.

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

Generally, electromagnetic coils are wound on a single coil such as a coil made of a coil of insulated wire, a winding frame (ie, a bobbin), or wound on an insulated iron core.

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

Examples of powder coatings used in the method of the present invention include epoxy powder coatings, polyester powder coatings,
Examples include acrylic powder paint and urethane powder paint. Among these powder coatings, it is preferable to use epoxy powder coatings because they enable rapid curing of the coating film and provide a coating film with excellent electrical and mechanical properties. Also, the thickness of the coating film formed on the coil surface of the electromagnetic coil is 0.1 to 10
mm is adopted, which protects and insulates the electromagnetic coil from the outside, and provides an insulated coil that does not damage the insulated copper wire. Paint film thickness is 10mm
If it is larger than this, the paint film will fall off (sagging), and if it is smaller than 0.1 mm, it will be difficult to maintain sufficient insulation from the outside, both of which are undesirable.

The solvent-free impregnating resin having thixotropic properties at room temperature used in the method of the present invention is one that decreases in viscosity and flows when shear force, that is, force is applied, but does not show fluidity when it is stationary.
For example, in order to impart thixotropic properties to solvent-free impregnating resins such as unsaturated polyester resins, epoxy resins, silicone resins, and polyurethane resins, fine particulate silica [such as Erosil (manufactured by Nippon Aerosil Co., Ltd.)] and Gelol D [Shin Nippon Chemical Co., Ltd.] are used.
Co., Ltd.], to which talc and other substances are added. The thixotropic property sufficiently retains its properties at room temperature and during heat curing. The amount added varies depending on the type and viscosity of the resin, but if the resin does not have sufficient thixotropic properties, the vacuum-impregnated resin will flow out, which is not desirable. Generally, the amount of the additive added is in the range of 0.5 to 30 parts by weight per 100 parts by weight of the solvent-free impregnating resin.

In the present invention, an electromagnetic coil on which a coating film has been formed is placed in a vacuum impregnation tank, and after the impregnation tank is evacuated, a solvent-free impregnating resin having thixotropic properties is injected into the electromagnetic coil. is completely filled. In that case, in the case of a coil wound around an iron core, the solvent-free impregnating resin penetrates into the coil from the interface between the iron core and the coil. In addition, if the coating film formed on the coil surface prevents the solvent-free impregnating resin from penetrating into the coil, small holes are provided in the coating film to allow the solvent-free impregnating resin to penetrate into the coil. It will be done.

During vacuum impregnation, the solvent-free impregnating resin flows due to pressure difference and enters the coil through the interface between the core and the coil or through the small holes in the coating film, while when it is stationary, the solvent-free impregnating resin does not flow. Therefore, it does not flow out from inside the coil. However, even if the solvent-free impregnating resin has thixotropic properties,
It often shows fluidity due to its own weight or temperature rise. In the method of the present invention, since the coating film is formed on the surface of the electromagnetic coil, the impregnated resin impregnated into the electromagnetic coil does not flow out from inside the electromagnetic coil.

Next, from the impregnated electromagnetic coil, excess solvent-free impregnating resin adhering to the coil or iron core is removed, and the solvent-free impregnating resin impregnated into the coil is cured by a normal method.

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 also effective in insulating the coil from the outside.Moreover, the solvent-free impregnated resin in the coil is cured while being completely filled inside the coil. This serves to insulate between the coil wires and prevent vibrations, so an insulated coil with extremely excellent performance 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 (wire diameter: 1
We will discuss the stator insulation of a corrosion-protected motor with parallel windings (slots are insulated with polyethylene terephthalate film).

First, heat the 3-phase 200V for 20 seconds to heat the coil at a coil temperature of approximately 200℃.
VEP 46-2] was applied by a fluidized dipping method to form a coating film having a thickness of 1 to 3 mm on the surface of the coil. The coil was placed in a vacuum impregnation tank, and Erosil #380 ( After adding and mixing 7 parts by weight of the solvent-free impregnating resin having thixotropic properties at room temperature, the excess impregnating resin adhering to the surface of the frame and coil was removed, and the impregnating resin was heated at 150°C. Curing was performed in a hot air circulation oven for about 3 hours.

The interior of the obtained stator was completely filled with cured resin. The obtained stator also has an insulation resistance of 10 ¹² Ω or more in water.
There was almost no decrease in MEG after being 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 energized and heated, and then a solvent-free coating having thixotropic properties at room temperature is applied. A method for insulating a coil, characterized by vacuum impregnation with mold impregnating resin and then curing. 2. The 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.