JPS61181111A - Molded high voltage transformer - Google Patents

Abstract

PURPOSE:To make zero a voltage difference between a high voltage coil and a magnetic core and minimize the gap between the high voltage coil and the magnetic core for reduction in size by molding a coil through close contact between the high voltage coil and a metal plate and inserting a magnetic core into such a molded coil. CONSTITUTION:Windings are respectively provided to a low voltage coil 1 and a high voltage coil 2 and these are engaged. A metal plate arranged along the external circumference of winding bobbin of a high voltage coil 2 is provided to the winding bobbin in such a manner that the protruded portion provided at the external circumference of winding bobbin is inserted into the hole pro vided at the periphery. A coil thus formed is provided within a mold die 4 and it is molded with mold resin 5. In this case, a gate port of mold die 4 is provided to the region where there is no metal plate 3. Thereby, a metal plate 3 is molded under the condition that it is pressed to the wall surface 4a of die with a molding pressure which causes the mold resin to flow into the molding die 4.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a molded high-voltage transformer that combines a low-voltage coil and a high-voltage coil, inserts a magnetic core into the molded coil, and is used as a high-voltage power source for electrostatic copying machines, etc. Regarding.

Conventional technology Conventionally, as shown in Japanese Patent Publication No. 5B-30730, for example, a low-voltage coil and a high-voltage coil are combined and fixed in a mold, and a thermosetting resin is press-fitted to harden the coil. There is a way.

This method uses a thermosetting epoxy resin with good adhesion to avoid creating voids, and it is necessary to lower the viscosity so that the resin can penetrate into the smallest details, so the amount of filler is reduced during casting.

Problems to be Solved by the Invention In such conventional methods, the expansion and contraction of the resin is large (
Therefore, after manufacturing the high-voltage coil, it is necessary to insert the magnetic core, but corona is generated by the electric field between the high-voltage coil and the magnetic core, so it was necessary to increase the insulation distance between the high-voltage coil and the magnetic core.

The present invention solves these problems, and aims to provide a molded high-voltage transformer that can be made compact by reducing the potential gradient between the high-voltage coil and the iron core to zero.

Means for Solving the Problems In order to solve the above problems, the present invention arranges a metal plate on the outer periphery of a high voltage coil bobbin, and installs the above high voltage coil and low voltage coil fitted together in a mold. Then, a molded resin is press-fitted, the resin is filled between the high-voltage coil and the metal plate, and the coil is formed with the metal plate closely attached to the outer periphery of the high-voltage coil by molding the coil and taking it out from the mold after molding.
A magnetic core is inserted into this molded coil, so that the potential difference between the high-voltage coil and the magnetic core can be reduced to zero, and miniaturization can be achieved.

Effect With the above-described configuration, the voltage generated in the high-voltage coil is insulated by the molded resin by grounding the metal plate on the outer periphery, and there is no need to consider insulation by inserting a magnetic core.

EXAMPLE An example of the present invention will be described below based on the drawings. 1st
The figure shows an embodiment of the molded high voltage transformer of the present invention.

In FIG. 1, 1 is a low-voltage coil, and 2 is a high-voltage coil, each of which is wound and fitted. 3 is a metal plate placed along the outer periphery of the winding bobbin of the high-voltage coil 2, and is attached to the winding bobbin by inserting a hole provided around the periphery into a convex portion provided on the outer periphery of the winding bobbin. It will be done. Further, the metal plate 3 is provided with a large number of stars in order to improve its adhesion to the molding resin.

FIG. 2 shows a state in which the coil assembled as shown in FIG. 1 is placed in a molding die 4 and molded with a molding resin 5. At this time, since the gate opening of the molding die 4 is provided in a portion where the metal plate 3 is not present, the metal plate 3 is pressed against the mold wall surface 4a by the molding pressure that causes the molding resin to flow into the molding die 4. It is molded in. Therefore, since the metal plate 3 is star-strapped, there is a large contact surface with the molded resin 5, and the metal plate 3 will not fall off even if the coil is taken out after molding.

FIG. 3 shows a high voltage transformer formed by inserting the magnetic core 6 into the coil molded in FIG. 2.

At this time, since the metal plate 3 and the magnetic core 6 are used while being grounded, no corona is generated in the gap 1I17 between the high voltage coil and the magnetic core.
This means that it can also be used in the Gakko Zero.

It goes without saying that the present invention can also be applied to square bobbins and the like.

Effects of the Invention As described above, according to the present invention, the high-voltage coil is molded with a metal plate in close contact with it, and the magnetic core is inserted into the molded coil to assemble it, so the potential difference between the high-voltage coil and the magnetic core is reduced. This makes it possible to minimize the air gap between the high-voltage coil and the magnetic core, allowing for miniaturization, which is extremely useful in practice.

[Brief explanation of drawings]

Fig. 1 is an assembly diagram of a coil according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of the coil shown in Fig. 1 installed in a mold and molded, and Fig. 3 is an explanatory diagram of a state in which the coil shown in Fig. 1 is installed in a mold and molded. It is a diagram configuring a high voltage transformer by inserting a magnetic core. DESCRIPTION OF SYMBOLS 1...Low voltage coil, 2...High voltage coil, 3...Metal plate, 4...Mold, 5...Mold resin, 6...
Magnetic core, 7... Gap agent Yoshihiro Morimoto Figure 1 Figure 2

Claims (1)

[Claims] 1. A high-voltage transformer that combines a low-voltage coil and a high-voltage coil and inserts a magnetic core into the molded coil,
A molded high-voltage transformer has a metal plate attached to the outer periphery of the high-voltage coil that is closely formed at the same time as the coil is molded, and a magnetic core is inserted into this molded coil.