JPS60136111A - Method of producing enameled 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] <Technical Field of the Invention> The present invention provides a method for cutting a plate that is smooth without bubbles and has a uniform float.
Enamel insulation MUI%! This relates to the H91 manufacturing method.

<Background of conventional technology and its problems> Conventionally, enamel M! 3-edged electric cotton is popularly decorated by coating a conductor with 7-layer enamel varnish diluted with an appropriate solvent and drying and curing it with a heat source such as electric heat, infrared rays, or hot air. .

However, in all of the above conventional methods, the varnish film is heated from the outside, and the solvent (volatile components) on the surface side of the film is first dried. When the amount of (non-volatile components) increases, the surface of the varnish film hardens before the internal solvent dries.

When the surface is hardened by further heating, the solvent is trapped inside, and when the temperature rises above its boiling point, the remaining solvent boils and tries to escape to the outside of the varnish film. As the surface hardening has already progressed, bubbles may form near the film surface, the bubbles may burst, or cracks may occur, resulting in a very smooth and thick surface. It was not possible to obtain a uniform enamel film.

When a varnish with low volatile components is used for lh, heating from the outside causes the film to dry and harden extremely quickly, resulting in the formation of bubbles, rupture, cracking, and other phenomena. . Therefore, the physical and electrical properties of the enamelled wire are significantly deteriorated.

In recent years, there has naturally been an emphasis on energy conservation in this field as well, and there has been a strong tendency to use wires with less volatile solvents, and creating a uniform skin for the enameled wire has become a serious problem for the reasons mentioned above. ° [C is here.

<Purpose of the invention> The present invention has been made in view of the current state of the prior art as described above, and can be applied not only to ordinary enamel varnishes but also to enamel varnishes 12 with low volatile components (solvents). The object of the present invention is to provide a method for manufacturing an enameled insulated wire having a bubble-free and smooth film.

As a result, a good enameled P/M can be produced without significantly deteriorating the electrical and physical properties of the enameled wire.

<Structure of the Invention> A feature of the present invention is that in baking an enamel varnish coating, whereas conventionally the coating was heated from the outside, at least in the initial stage of baking, an induction heating method is used. ,
The varnish is dried and hardened from the inside of the conductor.

Figure 1 shows the actual method of the present invention.
(The present invention will be described in more detail below based on the same amounts.

First, the conductor 1 (usually made of copper, aluminum, copper alloy, or aluminum alloy) is passed from the bottom to the top of the paint tank 21C containing enamel varnish, and varnish is applied to the outside of the conductor. Subsequently, the conductor 1 coated with this varnish is passed through an iE device, and the varnish coating layer is finished to a uniform thickness while removing an excess of 7 lbs. Next, this is introduced into the heating furnace 4, the solvent in the varnish coating layer is evaporated and dried in the drying area a of the heating furnace 4, and the dried varnish film is cured in the curing area of the furnace 4, It's grilled.

After the conductor 1' having the enamel coating layer which has been completely hardened in this way is cooled in the cooling area 0, the conductor 1' is passed back and forth several times between the upper and lower parts of the heating furnace 4, and the enamel coating layer is removed. Covering 1 is repeated until the enamel coating layer reaches a predetermined thickness, then it is taken out and wound onto a product bobbin (not shown).

In the present invention, an induction heating means made of fat conductive heating twill T is provided as a heating means for the drying area a in the heating furnace 4, and first the conductor 1 itself is heated. Therefore, applied? In the case of varnish, heating Δ is applied from the inside in contact with the conductor surface, and the solvent inside gradually evaporates and moves to the surface #Ij'i side of the varnish that has not yet hardened. Then, in the next step, the heating means for the curing area is used (heater 8 is used in this example), so the outside of the varnish film is gradually heated, the solvent on the surface side is volatilized and dried. Later the varnish itself is hardened. Therefore, the solvent is trapped inside and cannot be extracted to the outside as in the conventional C1, and the above-mentioned undesirable formation of bubbles, bursting, cracking, etc. are completely eliminated.

The above induction heating may be low frequency heating using commercial frequency or high frequency heating using high frequency, and -C may also be used.
From the point of view of improving productivity, high-frequency heating is preferable because it can heat quickly and has good heating efficiency.In the case of high-frequency heating, the operating frequency ranges from 1.000KH to 1.000KH.
A range of z is preferred. That is, heating efficiency is good between 10 and 1.000 KU<,i,oo.

KH2 or higher is not practical because equipment costs and operating costs increase.

In the case of the present invention, the induction heating of the kernels is performed in the drying area a.
Although this is an essential heating means, conventional heating means such as electric heating, infrared rays, and hot air can also be used in combination in this area a. This combination has the advantage that it can be converted into energy at a low cost.

According to the present invention, the heating means for the curing area can be not only the heater 8 of the above example, but also infrared rays and hot air, which have been commonly used in the past, can of course be used as the heat source. , the above-mentioned induction heating can be used in combination, or induction heating alone can be used. When used in combination with this induction heating, there is an advantage that energy conversion can be done at low cost.

Furthermore, as the enamel varnish used in the present invention I/C, any enamel varnish such as polyester, formal, polyester imide, polyester oxide, polyimide, etc. can be widely used. A noise that is not limited to any type.

<Execution fee> Coat a polyester varnish with a resin content (non-volatile component) of 50 cm on the outer periphery of a conductor (made of copper), heat and dry the varnish coating layer from the inside of the conductor using tS conduction heating, and then heat it with various heat sources. Heat to harden and harden the coating layer, then bake it.
This process was repeated several times to produce 7 tons of polyester insulated wire 'f, and the results shown in Table 1 were obtained. Note that a method using conventional heating means is also shown as a comparative example. -1 Method (Effects of the Invention) According to the method for producing an enamel insulated wire of the present invention, the varnish coated around the outer circumference of the conductor is dried or cured.
Since the conductor itself is heated by an induction heating coil, the varnish is gradually dried from the inside that contacts the conductor side, so that the solvent is not trapped inside due to hardening of the surface as in the past. Therefore, bubbles, cracks, etc. do not occur near the surface of the varnish coating, and a uniform coating of ¥σ (1'ft) can be achieved. In addition, it can be sufficiently applied to enamel varnishes with low volatilization power, and energy saving in the wire manufacturing process can be achieved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of an apparatus useful in carrying out the method of manufacturing an enamel insulated wire according to the present invention. 1... Conductor, 4φ... Heating furnace, T... Induction heating means (induction heating coil), a-... Drying area, b... Curing area. Patent applicant: Fujikura Electric Wire Co., Ltd.

Claims (1)

[Claims] A method for manufacturing an enameled insulated paper wire in which an enamel varnish is applied to the outer periphery of a conductor, and the enamel varnish is passed through a heating furnace to dry and harden the varnish coating layer. A method for manufacturing an enamel ZETSU U-Ten wire, characterized by the following.