JPH057805B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a method for manufacturing a rectangular insulated wire using an electrostatic powder coating method. [Technical background of the invention and its problems] In recent years, the method of manufacturing insulated wires using powder coating has been attracting attention from the viewpoints of pollution-free, resource-saving, and energy-saving, and among these methods, this method has the highest coating efficiency. , the electrostatic dynamic dipping method is particularly gaining attention in the field of insulated wire manufacturing. In this method, for example, charged synthetic resin powder is fluidized by dry air passing through a perforated plate placed below to form a fluidized bed, and a metal conductor is filled with the synthetic resin powder above this fluidized bed. This is a method in which synthetic resin powder is electrostatically attached to the surface through the coating zone, and then the attached synthetic resin powder is heated and fused and cured to form a coating. Usually, the metal conductor is placed horizontally in the coating zone. A method of passing in the direction is used. When forming an insulating film on a rectangular conductor using this method, in order to make the amount of powder adhesion uniform on each surface of the outer periphery, an anti-adhesion plate is movably placed along each surface and placed in a cloud of powder. A method for controlling the conductor exposure time has been proposed. However, with this method, highly accurate adhesion prevention plates must be placed on each side of the rectangular conductor. The problem is that the amount of adhesion varies, and the adhesion prevention plate must be changed depending on the size of the conductor. Furthermore, the synthetic resin powder is difficult to adhere to the curved portions near the corners of the rectangular conductor, resulting in a reduction in dielectric breakdown voltage. [Purpose of the Invention] The present invention has been made to solve these problems, and it provides a rectangular insulated wire with electrical characteristics, particularly high breakdown voltage, in which a film of uniform thickness is formed over the entire circumference. The purpose is to provide an easy manufacturing method. [Summary of the Invention] That is, the method of manufacturing a rectangular insulated wire using the electrostatic coating method of the present invention involves horizontally passing a conductor through a coating zone filled with charged synthetic resin powder, and coating the surface of the conductor with the synthetic resin powder. In a method for manufacturing a rectangular insulated wire, in which a resin powder is attached, and then the attached synthetic resin powder is heat-fused and cured on a conductor to form an insulating film, a predetermined interval is left below and above the conductor, respectively. A long adhesion amount adjustment plate is arranged parallel to the conductor, and two plates each having a large number of holes on both sides of the conductor are overlapped so as to be relatively movable, and the opening area can be varied. The present invention is characterized in that an adhesion amount adjusting plate is provided to adjust the amount of adhesion of the synthetic resin powder to the outer periphery of the conductor. Among the adhesion amount adjusting plates in the present invention, the adhesion amount adjusting plate disposed below the conductor prevents the synthetic resin powder rising from the fluidized bed from continuing to rise and adhering in large quantities to the lower surface of the metal conductor. The upper surface is preferably formed of an inclined surface having an angle of repose greater than or equal to the angle of repose of the synthetic resin powder used with respect to the horizontal surface. Further, since the adhesion amount adjusting plate disposed above the conductor is located below the exhaust duct, it can be curved upward in a convex shape. On the other hand, the adhesion amount adjustment plate placed on the side of the conductor has an opening in order to equalize the amount of powder adhesion on the corners of the rectangular conductor with the amount of adhesion on other flat parts. , the area of this opening can be changed by movably superposing two multi-hole plates. Furthermore, as these adhesion amount adjustment plates, those made of synthetic resin are suitable, and the installation position of the adhesion amount adjustment plates, that is, the distance from the metal conductor to these adhesion amount adjustment plates, depends on the size of the metal conductor. It is desirable to make appropriate adjustments to form a coating with as uniform a thickness as possible depending on the electric charge and density of the synthetic resin powder and the like. [Embodiments of the Invention] Examples of the present invention will be described below. Example As shown in the drawing, Scotchicast (trade name of epoxy resin powder manufactured by 3M, USA) 1 charged with a charging voltage of -65 kV was placed on a perforated plate 3 at a rate of 300 cm in a painting chamber 2 with a length of 70 cm. It was fluidized by the dry air that was passed through at a flow rate of 100 min to form a fluidized bed in the lower part of the coating chamber 2. A rectangular copper wire 5 of 2.0 x 5.0 mm was passed horizontally about 10 cm above the fluidized bed 4 at a speed of 3.0 m/min to deposit the charged Scotchicast on the surface. At this time, an inverted V-shaped plastic adhesion amount adjustment plate 6 is placed below the rectangular copper wire 5, and two adhesion amount adjustment plates 7 curved in the opposite direction to the rectangular copper wire 5 are placed on both sides. . Note that the above-mentioned adhesion amount adjustment plates 6, 7, 7', and 8 were all arranged parallel to the rectangular copper wire 5. Note that the arrows in the figure indicate the flow of Scotchicast toward the dust collector (not shown). Next, the rectangular copper wire with Scotch cast adhered to its surface was inserted into a heating furnace with a furnace temperature of 350 to 430°C and a furnace length of 3.5 m at a speed of 3.0 m/min to heat-fuse the Scotch cast and further harden it. . The ratio of the thickness of the corner portion and the curved portion around the corner portion to the coating thickness of the flat portion of the obtained rectangular insulated wire was measured. The measurement results are shown in the table below. The comparative example shown in the table is based on a method of controlling the exposure time of a rectangular copper wire in a powder cloud, and is the measurement result for a rectangular insulated wire manufactured under the same conditions.

[Table] Figure 2 shows the adhesion amount adjusting plate 7 (7') used in Figure 1.
(also the same structure), two slightly curved plates 11 and 11' each having a large number of circular holes 10 and 10' are superimposed, and the long holes 12 of the lower plate 11' are
It has a structure in which a thumbscrew 13 attached to the upper plate 11 is inserted into the upper plate 11 to slidably hold these plates. The area of the openings 14 in the two plates is adjusted depending on the amount of powder adhering to the outer periphery of the rectangular copper wire, and is fixed by tightening the thumbscrew 13. [Effects of the Invention] As is clear from the above examples, according to the present invention, an insulating film having a uniform thickness is formed all around the conductor, and therefore a rectangular shape with excellent electrical and mechanical properties is formed. Insulated wires can be manufactured.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view for explaining the coating process in an embodiment of the present invention, Fig. 2a is a plan view of the adhesion amount adjusting plate used in Fig. 1, and Fig. 2b is its A-A
It is a sectional view along a line. 2...Painting room, 3...Perforated plate, 4...Fluidized bed,
5... Flat copper wire, 6, 7, 7', 8... Adhesion amount adjusting plate, 14... Opening.

Claims (1)

[Claims] 1. A conductor is passed horizontally through a coating zone filled with charged synthetic resin powder to adhere the synthetic resin powder to its surface, and then the attached synthetic resin powder is removed. In a method for manufacturing a rectangular insulated wire in which an insulating film is formed on a conductor by heat fusing and curing, a long adhesion amount adjusting plate is provided parallel to the conductor at a predetermined interval below and above the conductor. At the same time, on both sides of the conductor, two plates each having a large number of holes are superimposed so as to be movable relative to each other, and an adhesion amount adjustment plate capable of changing the opening area is disposed, thereby increasing the amount of adhesion to the outer periphery of the conductor. A method for manufacturing a rectangular insulated wire using an electrostatic coating method, which comprises adjusting the amount of the synthetic resin powder deposited. 2. The electrostatic coating method according to claim 1, wherein the adhesion amount adjusting plate below the conductor is formed of an inclined surface whose upper surface has an angle of inclination greater than the angle of repose of the synthetic resin powder with respect to the horizontal surface. A method for manufacturing flat insulated wires.