JPH05152144A - Molded transformer - Google Patents

Abstract

PURPOSE:To provide a molded transformer wherein the dimensional accuracy of a transformer shape and a user terminal is enhanced, its production process is simplified by reducing the number of comonents, its productivity is enhanced, an investment in the automation production facilities of its assembly process is reduced, its cost is low, its safety is high and its quality is high. CONSTITUTION:A transformer main body whose closed magnetic circuit is constituted of an EE-shaped or EI-shaped ferrite core 27 is formed in such a way that a thermoplastic resin 28 whose molecular weight is low at 15000 or lower and whose molten viscosity is at a low molten viscosity of 500PS or lower is molded by using a mold at a low injection pressure. Thereby, a molding stress, a molding compression stress and the like are not exerted on the ferrite core 27, it is possible to prevent an inductance from being dropped remarkably and a core from being broken, and the whole outer circumference of the transformer main body can be resin-molded by using the mold. Thereby, the number of components can be reduced and it is eliminated that components are fitted and combined. As a result, the dimensional accuracy of a transformer shape and user terminals 26 can be made high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold transformer used in various video equipment, home appliances, audio equipment, industrial equipment, communication equipment and the like.

[0002]

2. Description of the Related Art A conventional transformer is constructed as shown in the internal structure diagram of FIG. That is, the through hole 2 in the center
And a lower end flange 4 at the lower end of each end, and a manufacturer terminal 5 for winding wiring, and a user terminal 6 used at the time of mounting, which are integrated with each other, are wound around a winding frame 1 and a conducting wire 3 such as a copper wire is wound around the manufacturer. A transformer body formed by inserting an EE-type or EI-type ferrite core 7 into a coil portion wound around the terminal 5 and wiring is inserted into a plastic resin case 9, and a highly insulating resin 10 such as silicon is used. Was molded and sealed with a plastic resin bottom plate 11 so that the user terminals 6 were exposed to form a transformer.

[0003]

In such a conventional transformer, the number of parts is large and the production process is complicated. Considering the original function of the transformer, the winding process and the core assembly process are indispensable, and capital investment for automation has a large effect, but there is no problem, but the subsequent insertion into the case 9 and the high insulating resin 10 Although the steps such as casting and inserting the bottom plate 11 are for additional functions, the weight of capital investment for automation is very large. The investment effect is also small, which in turn puts pressure on the profitability.

The surface mountable transformer has the same structure, but it is a combination of a bare transformer, a case, and a bottom plate, and the transformer shape and the dimensional stability of user terminals are very poor. , It is a cause of the deterioration of the yield when the user automatically mounts the transformer. In order to reduce the number of products and to improve the transformer shape and the dimensional accuracy of user terminals, it is possible to achieve by molding the entire transformer with resin, but an EE type or EI type closed magnetic circuit type ferrite core is used as the magnetic material. In this case, it was said that the core could be cracked or the inductance could be significantly reduced due to molding stress, and the entire transformer could not be resin-molded.

Further, in the case of the surface mountable transformer, the time required for the mounting process by the user is 200 to 250 although it takes a short time.
Since thermosetting resin such as epoxy resin is generally used as the mold resin material because it is exposed to a high temperature of ℃, the molding time is long and deburring is required during molding, resulting in high capital investment and high productivity. Was very bad.

The present invention solves the above-mentioned conventional problems by improving the dimensional accuracy of the transformer shape and the user terminal,
An object of the present invention is to provide a mold transformer of low cost, high safety, and high quality, which simplifies the production process by reducing the number of parts, improves the productivity, and reduces the investment of automated production equipment in the assembly process.

[0007]

In order to achieve this object, the present invention provides a transformer body refined by inserting an EE-type or EI-type ferrite core in combination and molding it with a low molecular weight and a low melting point. A ferrite core type mold transformer is constructed by molding a viscous thermoplastic resin at a low injection pressure.

Further, in the case of a surface mountable transformer, a special thermoplastic resin such as liquid crystal polymer having a higher heat resistance is molded by a low injection pressure,
Construct a ferrite core type surface mount compatible mold transformer.

[0009]

[Operation] As described above, by molding the entire transformer with a low molecular weight, low melt viscosity thermoplastic resin at a low injection pressure, stress such as molding stress and molding shrinkage is not applied to the ferrite core, and the inductance is significantly reduced. And core cracks can be prevented, and even when an EE-type or EI-type closed magnetic circuit type ferrite core is used as the magnetic material, the entire outer circumference of the transformer body can be resin-molded, and the number of parts is conventional. The transformer case, bottom plate, and casting resin are reduced to 3 points, and the combination of parts is eliminated, and the transformer shape and user terminal dimensions can be improved. Furthermore, the production process can be simplified to only the molding process, and the capital investment for automation can be reduced. In the case of a surface mountable transformer, it can be achieved by molding with a low injection pressure using a special thermoplastic resin such as a liquid crystal polymer having a high heat resistance of 250 ° C. or higher. Since the equipment can be shared by making changes, productivity can be improved and the investment in automated production equipment for the assembly process can be reduced, resulting in a low cost, high accuracy, high safety and high quality ferrite core type mold transformer. can do.

[0010]

【Example】

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an internal structure diagram of a transformer according to an embodiment of the present invention. In FIG. 1, a through hole 22 is provided in the center, and a lower end collar 24 at the lower end of each end is integrally formed with a manufacturer terminal 25 for winding wiring.
And the reel 2 in which the user terminals 26 used by the user are planted
1, a transformer main body configured by winding a conducting wire 23 such as a copper wire and winding and winding around a maker terminal 25 and inserting an EE-type or EI-type ferrite core 27 in combination is provided only for the user terminal 26. In order to expose the core, the transformer main body is molded with a low-melting-temperature thermoplastic resin 28 having a low molecular weight of 15000 or less and a melt viscosity of 500 PS or less with a low molding stress at a low injection pressure. Make up a type mold transformer.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the same drawings used in the first embodiment. In the mold transformer described in the first example, as an application to a surface mountable transformer, the transformer body has a low molecular weight of 15000 or less with a low molding stress, a low melt viscosity of 500 PS or less, and further 250 ° C or more. By molding a special thermoplastic resin 28 such as a heat-resistant liquid crystal polymer at a low injection pressure, a closed magnetic circuit ferrite core type surface mount compatible mold transformer is constructed.

[0012]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, the shape of the transformer and the dimensions of the user terminals are made highly precise, and the production process is simplified by reducing the number of parts, so that the productivity is improved and the assembly process is automated. Investment can be reduced,
Low cost, high precision, high safety, high quality EE type or E
It is possible to realize and provide an I-type closed magnetic circuit ferrite core type mold transformer.

[Brief description of drawings]

FIG. 1 is a sectional view showing an internal structure of a mold transformer according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the internal structure of a conventional transformer.

[Explanation of symbols]

 21 winding frame 22 through hole 23 conducting wire 24 lower end flange 25 maker terminal 26 user terminal 27 ferrite core 28 thermoplastic resin

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Katsumi Matsumura 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A transformer main body comprising a coil bobbin, in which a conductive wire such as a copper wire is wound around a winding frame having a through hole in the center, and a EE type or EI type ferrite core is combined and inserted into a coil body.
A mold transformer made by molding a transformer body with a low molecular weight and low melt viscosity thermoplastic resin with low molding stress so that only the terminals used during mounting are exposed. 2. The mold transformer according to claim 1, wherein a liquid crystal polymer having high heat resistance is used as the thermoplastic resin.