JPS58162015A - Small sized transformer - Google Patents

Abstract

PURPOSE:To make easy automatic assembling and make less an eddy current by inserting a core into the center hole of a bobbin provided for the primary and secondary coils and by winding magnetic wire material to the exteral circumference of bobbin so that both end surfaces of core are opposed in contact each other. CONSTITUTION:An internal magnetic core 3 is inserted throuh the center hole of a bobbin 2 providing the primary and secondary coil 1. The internal magnetic core 3 is formed by bundling magnetic wire materals such as permalloy etc. into a circular-cylinder and then hardening it by baking or with adhesive agent. Both end surfaces are aligned by polishing etc. and are a little extruded from the bobbin 2. Both external side surfaces of bobbon 2 are integrated with the winding guide frames 4, 4, the magnetic wire material 5 which is the same material as the internal magnetic core 3 is wound around the external circumverence of the bobbin 2 for the specified number of turns, and this magnetic wire material 5 becomes the external magnetic core and forms a closed magnetic circuit in combination with the internal magnetic core 3. Since both end surfaces of internal magnetic core 3 are extruded a little from the bobbin 2, the magnetic wire material 5 is firmly in contact with the internal magnetic core 3, not generating a gap at this part.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small transformer connected to various electronic circuits.

In the conventional small transformer of this type, its iron core #iB
It was made by punching out materials into , L-shapes, combining them, butting them together, and then laminating them. However, with this structure, assembly of the iron core is troublesome and automatic assembly is difficult to employ, and a lot of material is wasted when punching and forming the core. Further, even though the rolled plate material generally used as KJt material has excellent magnetic properties in the rolling direction, the magnetic properties deteriorate considerably in the direction perpendicular to the rolling direction. For this reason, in L-shaped or L-shaped iron cores, there is always a portion in the magnetic circuit with poor magnetic properties, resulting in a decrease in efficiency.

The present invention aims to eliminate the drawbacks of the above-mentioned prior art, and one embodiment thereof will be described below.

In FIGS. 1 and 2, an inner magnetic core 3 passes through a center hole of a bobbin 2 around which primary and secondary coils 1 are wound. The inner magnetic core 3 of this embodiment is made by bundling magnetic wires such as permalloy into a cylinder and hardening them by firing or using an adhesive. It has a length tube that slightly protrudes from 2. A winding guide frame 4.4 is integrally protruded from both sides of the bobbin 2, and a magnetic wire 5 made of the same material as the inner magnetic core 3 is fixed around the outer periphery of the bobbin 2 using the winding guide frames 4, 4 as a guide. The magnetic wire 5 is wound □ times by the number of turns, and this magnetic wire 5 becomes an outer magnetic core and cooperates with the inner magnetic core 3 to form a closed magnetic circuit.

The magnetic wire 5 is wound around the bobbin 2 using a well-known automatic winding machine (not shown) used when winding the coil It. Because of the protrusion, the magnetic wire 5 is strongly joined to the inner magnetic core 3, and no gap is created in this portion.

The inner magnetic core 3 may be bundled into a prismatic shape, or may have a conventional laminated plate structure.

According to the compact transformer having this configuration, automatic assembly can be applied to the opening, and there is almost no wastage of materials, so it can be manufactured at low cost. Moreover, the easy axis of magnetization of the inner magnetic core and outer magnetic core perfectly aligns with the magnetic path, and compared to the conventional laminated plate structure, the eddy current loss is lower and the characteristics are better. Since it protrudes from the outer magnetic core, the wire of the outer magnetic core is tightly wound around both end faces, and the gap in this area becomes extremely small, resulting in a truly remarkable effect.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view showing an embodiment of a small transformer according to the present invention, and FIG. 2 is a sectional view taken along the line B--U in FIG. 1... Coil 2... Bobbin 3... Inner magnetic core 4... Winding guide frame 5... Magnetic wire (outer magnetic core) Takaharajin Seikosha Co., Ltd. No. 1 m= Figure 2 □ 5

Claims (1)

[Claims] 1. An iron core is inserted into the center hole of a bobbin around which primary and secondary coils are wound, and a magnetic wire is wound around the outer periphery of the bobbin so that both end surfaces of the iron core are in contact with each other. A small transformer that is characterized by: 2. The small transformer according to claim 1, wherein the bobbin is integrally provided with winding guide frames for the magnetic wire on both outer surfaces thereof. 3.% The small transformer according to claim 1, wherein both end surfaces of the iron core slightly protrude from the bobbin. 4.41 The small transformer according to claim 1 or 3, wherein the iron core is a bundle of magnetic wires.