JPH063696B2 - Insulated wire manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing an insulated wire by an electrostatic fluidized immersion method.

[Technical Background of the Invention and Problems Thereof] In recent years, a powder coating method, particularly an electrostatic fluidized dipping method, has been adopted as a method for producing a rectangular insulated wire from the viewpoints of no pollution and energy saving.

In this method, a rectangular conductor is passed horizontally through a charged synthetic resin powder cloud to adhere the powder to the surface and then passed through a heating furnace to melt the powder, thereby forming an insulating coating layer. However, in order to obtain a coating layer having a uniform thickness, it is necessary to keep the state in the coating chamber constant.

However, when manufacturing a long wire, powder must be supplied from the hopper to the coating chamber through the powder supply port, and the concentration of the powder cloud and the pressure inside the coating chamber fluctuate at this time. It has a drawback that a uniform film thickness cannot be obtained.

The coating chamber A'has a structure as shown in FIG. 3, for example, and is provided with an exhaust port 2 having a damper 1 at the upper part, an electrode 3 for ionizing dry air and a porous plate 4 at the lower part. The powder supply port 5 is arranged at the upper side of the coating chamber. The powder is intermittently supplied from a hopper (not shown) above the supply port. Reference numeral 6 is a rectangular conductor, and reference numerals 7, 8 and 9 are adhesion amount adjusting plates arranged in parallel on the upper, lower and lateral sides of the rectangular conductor.

In the coating chamber having the above structure, the powder is dropped from the powder supply port 5 onto the fluidized bed 10. However, at this time, the concentration of the powder cloud 11 and the room pressure fluctuate, which causes the above problems. Cause Therefore, such a method has a drawback that the insulation breakdown voltage of an insulated wire, particularly a rectangular insulated wire, is not stable.

[Object of the Invention] The present invention has been made to solve the above-mentioned drawbacks.
It is an object of the present invention to provide a method for manufacturing an insulated wire that can reduce the variation in film thickness even when powder is supplied.

[Summary of the Invention] That is, the present invention provides a method for producing an insulated electric wire by an electrostatic fluidized dipping method by sequentially passing a conductor running in a horizontal direction through a coating chamber and a heating furnace, wherein a porous plate in the coating chamber is provided. By forming a fluidized bed and a powder cloud, and passing a conductor through the powder cloud while maintaining the level of the fluidized bed above the powder supply port outlet, the concentration of the powder cloud during powder supply Also, it is possible to suppress fluctuations in the room pressure as much as possible, and thus to obtain an insulated wire having a uniform film thickness.

The synthetic resin powder used in the present invention includes epoxy resin, thermosetting resin powder such as curable polyester resin, and thermoplastic resin powder such as phenoxy resin, polytetrafluoroethylene resin, and polyamide resin. Although there is a body, thermosetting resin powder is particularly suitable for obtaining the characteristics of the insulated wire.

[Embodiment of the Invention] An embodiment of the present invention will be described below.

FIG. 1 shows a coating room A used in one embodiment of the method of the present invention.
3 is shown, and the same parts as those in FIG. 3 are indicated by the same symbols.

Arrangement of damper 1, exhaust hole 2, electrode 3, perforated plate 4 and adhesion amount adjusting plates 7, 8 and 9 and rectangular conductor 6 in coating room A
The positional relationship with is the same as in FIG. In the coating chamber A having the above structure, powder is supplied from the hopper 12 through the powder supply port 5, and the outlet 5a of the powder supply port 5 is the fluidized bed 10
Work is performed with the level set so that it is always positioned below the level 10a.

For example, a capacitance level meter 13 is installed at a predetermined position, and the output signal of this level meter is input to the controller 14,
The controller 14 opens the valve 15 and vibrates the vibration exciter 16 that imparts vibration to the hopper 12 when the powder level 10a drops to a predetermined position.

FIG. 2 shows the change in the finished thickness of the rectangular insulated wire after the insulation coating is baked when the above method is used. The manufacturing conditions at this time are shown below.

Synthetic resin powder …… EC208 (Sumitomo Deyureze epoxy resin powder name) Flat conductor ………… 2.0 × 5.0 (mm) Cu Coating thickness ……… 100μm Linear velocity ……… 3.0m / min Heating furnace Temperature …… 400 ～ 450 ℃ Coating room length ………… 700mm Voltage ………… -50KV Fluidizing air volume …… 100 / min Powder supply port …… 50mmφ The fluidizing layer thickness is controlled to 75mm, The distance between the powder supply outlet and the perforated plate is 10 mm.

As is clear from Fig. 2, although a slight thickness variation is recognized during powder supply, the control target range 2.175 to 2.225 (mm) is sufficiently satisfied. In this case, it is necessary to change the primary side voltage. There is no.

FIG. 4 shows changes in the finished thickness when a rectangular insulated wire is manufactured using the coating chamber A ′ shown in FIG. 3, except that the manufacturing conditions are the same except for the structure of the powder supply section. It is similar to FIG. In this case, a large thickness change occurs immediately after the powder is supplied, and the primary side voltage needs to be changed accordingly. Furthermore, the target control range for the finished thickness is 2.150 to 2.250 (m
m) should be set larger.

Although the above examples have been described with respect to the rectangular insulated wire,
It goes without saying that the present invention can be applied to insulated wires having a round or irregular cross section.

[Effects of the Invention] As described above, according to the method of the present invention, the insulated wire is manufactured by setting the level of the fluidized layer above the powder supply port. It is possible to suppress variations in thickness to be small, and thus it is possible to manufacture an insulated wire having excellent dielectric breakdown characteristics.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a coating chamber used in the method of the present invention, FIG. 2 is a graph showing changes in the finished thickness of a rectangular insulated wire manufactured by the method of the present invention, and FIG. Is a cross-sectional view of a coating chamber used in the conventional method, and FIG. 4 is a graph showing changes in the finished thickness of a rectangular insulated wire manufactured by the conventional method. A, A '... Coating room 5 ... Powder supply port 6 ... Rectangular conductor 10 ... Fluidized bed 12 ... Hopper

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-123611 (JP, A) JP-A-56-138815 (JP, A)

Claims (1)

[Claims] 1. A method for producing an insulated wire by an electrostatic fluidized dipping method in which a conductor running in a horizontal direction is sequentially passed through a coating chamber and a heating furnace, and a fluidized bed and a powder cloud are provided on a perforated plate in the coating chamber. And a conductor is passed through the powder cloud while maintaining the level of the fluidized bed above the outlet of the powder supply port.