JPS58214222A - Method of producing flat enameled 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] [Technical field of invention] The present invention relates to a method for manufacturing rectangular enamelled wire.

[Technical background of the invention and its problems] Conventionally, the method of forming an insulating coating on an enamelled wire has been to apply a solvent-based insulating varnish and bake it. In recent years, various solvent-free coating methods have been developed. An electrostatic coating method is known as one of such solvent-free coating methods.

This electrostatic coating method includes electrostatic dynamic dipping, electrostatic spraying, etc. Synthetic resin powder is deposited on the enamelled wire conductor using these methods, and then the powder is deposited by heating. Enamelled wire is manufactured by fusing them together. At this time, the thickness and outer diameter of the insulating coating are adjusted by adjusting the voltage for charging, the amount of air, and the amount of powder for fluidization and spraying.

However, in the electrostatic coating method, due to the variation in the particle size of the synthetic resin powder itself, the above-mentioned adjustment method causes unevenness on the coating surface and the finished dimensions also vary by ±1.
There was a variation of about 0%. Therefore, compared to the solvent-based coating method, this method has the drawbacks of lowering the space factor of the insulated wire and causing variations in characteristics such as dielectric breakdown voltage.

[Object of the Invention] An object of the present invention is to provide a method for manufacturing a rectangular enameled wire in which the coated surface of the rectangular enameled wire is smoothed by an electrostatic coating method.

[Summary of the Invention] The method for manufacturing a rectangular enameled wire of the present invention involves depositing synthetic resin powder on the surface of a rectangular conductor by electrostatic coating, fusing and integrating the powder by heating, and then applying it to a WA plate. It is characterized in that while the layer is above the softened portion, the surface of the fusion layer is pressed and smoothed using a pressure roller.

FIG. 1 is a process diagram of the method of the present invention, and FIG. 2 is a perspective view showing the state of smoothing by a pressure roller.

As shown in FIG. 1, in the present invention, a conductor supply bobbin 1
Synthetic resin powder is coated on the outer periphery of the conductor C supplied from the powder coating section 2, and this synthetic resin powder is applied to the baking furnace 3.
In this step, the powders are fused together by heating. Next, as shown in FIG. 2, this melted M layer is pressed by a pressure roller 4 at a temperature higher than the softening temperature to smooth the surface.
After being cooled and solidified, it is wound onto a winding bobbin 5. Note that the spacing between the rollers is set to the target size of the rectangular enameled wire. The powder used may be a thermosetting resin or a thermoplastic resin, and in the case of the former, the method of the present invention is applied after melting, and in the case of the latter, after curing. The temperature at which the pressure roller passes is desirably higher than the softening temperature of the resin by 20° C. or higher in order not to leave any stress inside the coating, and it is also good to consider that the temperature should not cause deterioration of the resin. It is therefore appropriate to insert a pressure roller in the section where the coated wire exits the baking oven and is being cooled. Further, the pressure rollers may be provided in a plurality or in a single set, and can be installed not only in the thickness direction of the enameled wire but also in the width direction.

Next, the present invention will be explained in more detail with reference to Examples.

EXAMPLE In common with Example 1.2, the method of the present invention was carried out according to the steps shown in FIG. 1, and a rectangular copper wire of 2.4 mm x 80 mm was used as the rectangular conductor. The electrostatic coating device used was an electrostatic dynamic immersion powder coating device manufactured by Electrostatic Equipment Co., Ltd. I Model-300 (USA), the baking furnace body length was 6 mm, and the pressure roller was made of Teflon and had a diameter of 5 mm and a length of 100 mm. Two pieces are installed parallel to each other in the thickness direction. The spacing between the rollers was set at 2°60 in, and the amount of fluidized air was 50 in.
β/min.

The linear speed was 3.2 m/min.

(1) Epoxy resin powder (XR5256 manufactured by 3M - thermosetting resin) was used as the synthetic resin powder. The charging voltage was -43 KVDC, the baking furnace temperature was 310°C at the inlet and 420°C at the outlet, and the surface temperature of the rectangular wire at the pressure roller was 230 to 260°C. In addition, the film softening temperature (
Thermal deformation temperature) is 108°C.

(2) Thermoplastic polyester (PE5-140P manufactured by Toagosei Kagaku Co., Ltd.) was used as the synthetic resin powder.

The charging voltage was -47 KVDC, the baking furnace temperature was 350°C at both the inlet and outlet, and the rectangular wire surface temperature at the pressure roller position was 190 to 220°C. The film softening temperature (thermal deformation temperature) is 139°C.

In order to see the effects of the method of the present invention according to the above examples, comparative example (1) was conducted under the same conditions as the above examples (1) and (2) except for the use of a pressure roller. ,(2)
shall be. Examples (1), (2), Comparative Examples (1), (2)
The dielectric breakdown voltage, finished thickness, finished width and coating thickness were measured at positions a to a shown in Figure 3 respectively)
was measured. The measurement results are shown in the table below.

(Left below) (Note>*-------fJa, b, c, g, h,
i) As is clear from these results, the rectangular enamelled wire obtained by the method of the present invention has a more uniform coating thickness, an improved space factor, and less dielectric breakdown than the conventional wire that does not use a pressure roller. The voltage also increased.

[Effects of the Invention] As is clear from the above description, the method of the present invention can be used to electrostatically coat synthetic resin powder on the surface of a rectangular conductor and fuse and integrate the powder by heating. The surface of the layer is smoothed and can provide an excellent rectangular enameled wire.

[Brief explanation of drawings]

Fig. 1 is an example of a process diagram of the method of the present invention, Fig. 2 is a perspective view showing the state of smoothing by the pressure roller of Fig. 1, and Fig. 3 is a cross-sectional view of a flat wire made by the method of the present invention. This figure shows the measurement position of the coating thickness. 1... Conductor supply bobbin 2...
・・・・・・・・・Powder coating part 3・・・・・・・・・・・・
・Baking furnace 4・・・・・・・・・Pressure roller 5・・・・・・
・・・・・・Take-up bobbin C・・・・・・・・・・・・
・Conductor■・・・・・・・・・・・・Patent attorney representing the coating Suyama Sa - (1 other person) Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) After applying synthetic resin powder to the surface of a rectangular conductor by electrostatic coating and fusing and integrating this powder by heating,
A method for producing a rectangular enameled wire, which comprises applying pressure to the surface of the layer using a pressure roller to smooth it. (2) The method for manufacturing a rectangular enameled wire according to claim 1, wherein the pressurization is performed while the fusion layer is at a temperature equal to or higher than the softening temperature.