JP2987646B2 - Small transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small transformer used for various electric appliances.

[0002]

2. Description of the Related Art FIG. 4 is an exploded perspective view of a small transformer shown as a conventional example, partially cut away, and FIG. 5 is a vertical sectional side view of the transformer. In these drawings, reference numerals 1 and 2 denote the same E-shaped core formed of ferrite material, 3 denotes a bobbin, 4 denotes a secondary coil wound on the bobbin 3, and 5 denotes a secondary coil wound on an upper layer. Primary coil. Bobbin 3 has coils 4, 5
Have end flanges 3b, 3c at both ends of the rectangular tube portion 3a on which the wire is wound, and trapezoidal portions 3d, 3e are formed thick under the end flanges 3b, 3c. Terminal pins 6a, 6b, 6c for fixing the ends of the coils 4, 5 to the trapezoidal portions 3d, 3e.
And 7a, 7b, 7c are implanted.

In the above-mentioned small transformer, after winding the coils 4 and 5 around the bobbin 3, the coil ends are fixed to predetermined terminal pins, and then the center leg is inserted into the square tube portion 3a of the bobbin 3. Then, the E-shaped cores 1 and 2 are assembled.

[0004]

A small transformer is used for many electric and communication devices such as a flash discharge light emitting device for photographing, a desk calculator, and the like.
A small transformer that has been reduced to a certain extent has been proposed. It is important to reduce the size of such a small transformer without lowering the efficiency, but it is particularly necessary to reduce the height of the transformer due to the built-in space. An object of the present invention is to develop a flat compact transformer in which the height of the transformer is reduced without lowering the efficiency.

[0005]

In order to achieve the above-mentioned object, according to the present invention, there is provided a bobbin in which a winding tubular portion is divided by a middle flange provided between both end flanges, and a winding tubular portion. It comprises a wound primary coil and a secondary coil, terminal pins provided on each of the end flange and the middle flange, and an EE-shaped core in which a central leg of the E-shaped core is inserted into the winding tubular portion and assembled. In the small transformer obtained, the middle flange is formed near the one end flange of the bobbin, and the primary coil is formed by the middle flange and the other end flange in a first winding section formed by the middle flange and the one end flange. The above-mentioned secondary coil is wound around each of the second winding sections, and further,
The E-shaped core on one side of the EE-shaped core is
It has a leg extending to the position of the middle collar, and the E-shaped core on the other side is
It has a configuration that has legs extending from the end flange to the position of the middle collar
We propose a compact transformer characterized by this. Further, the present invention proposes a small transformer in which one E-shaped core is made of a conductive material and the other E-shaped core is made of an electrically insulating material .

[0006]

In this small transformer, the winding tubular portion of the bobbin having end flanges at both ends is divided into a first winding section and a second winding section by a middle flange. Are formed near one end flange. That is, the first winding segment winding width is narrow and a second winding segment is winding width is widened, the first winding segment primary coil small number of windings have been described above, also, the winding A large number of secondary coils are each wound around the second winding section. As a result, the transformer becomes a flat transformer whose height is lower than that of the conventional small transformer in which the primary coil is wound on the upper layer of the secondary coil, and terminal pins are planted on the two end flanges and the middle flange. Many terminals
That Ki de be provided at a sufficient interval.

[0007] Further, since the joint between the leg end faces of the two E-shaped cores is located at the middle flange position, the transformer efficiency is improved as compared with the case where the joint between the leg end faces is provided at the position inside the coil. By making the core electrically conductive, the impedance of the primary coil is increased, and by making the other E-shaped core electrically insulating, accidents and heat generation of leakage current flowing through the core are prevented.

[0008]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway exploded perspective view of a small transformer showing an embodiment of the present invention, and FIG. 2 is a longitudinal side view of the transformer.

Reference numeral 50 denotes a bobbin made of a synthetic resin material. End flanges 50b and 50c are provided at both ends of a rectangular tube portion 50a forming a winding portion.
Is formed, and a middle collar 50 is provided between the end collars 50b and 50c.
d is integrally formed as shown.

The middle flange 50d is formed near one end flange 50b, and the rectangular tubular member 50a is divided into a first winding section 51 and a second winding section 52 by the middle flange 50d. A primary coil 53 is wound on the first winding section 51, and a secondary coil 54 is wound on the second winding section 52, and an insulating tape 55 is wound on the surface of these coils. I have.

Further, terminal pins 56a to 56c and 57a to 57c are provided on the trapezoidal portions 50e, 50f formed thick on the lower surfaces of the end flanges 50b, 50c in a direction perpendicular to the cylinder axis of the rectangular cylinder 50a.
Are further implanted, and terminal pins 58a to 58c are also implanted in the middle flange 50d.

The bobbin 50 is wound as shown in FIG. That is, after the winding start end is fixed to the terminal pin 56a, the first winding section 51 between the end flange 50b and the middle flange 50d is formed.
The primary coil 53 is formed by winding a number of turns to form a primary coil 53, and the winding end is fixed to the terminal pin 58c. Next, the secondary coil 54 is formed by fastening the winding start end to the terminal pin 58a and winding it several thousand turns around the second winding section 52 between the middle flange 50d and the end flange 50c. Then, the winding end is fixed to the terminal pin 57c.

In the bobbin 50 on which the coils 53 and 54 are wound as described above, two E-shaped cores 59 and 60 having different lengths of the leg portions shown in FIG. And assemble them. The E-shaped cores 59 and 60 are formed of a manganese-based ferrite core. Of the two E-shaped cores 59 and 60, the core 59 is a conductive manganese-based ferrite core, and Can use a nickel-based ferrite core that is electrically insulating.

In the small transformer constructed as described above, the low-voltage side terminal pins 56a, 58a, 58c are sufficiently separated from the high-voltage side terminal pin 57c. If an electrically insulating core 60 is used for the secondary coil 54 that generates a high voltage, the primary coil 53 passes from the secondary coil 54 through the cores 60 and 59. The leakage current flowing into the core is eliminated, and the transformer loss due to heat generation of the core is reduced.

[0015]

As described above, according to the small transformer according to the present invention, the middle flange provided between the end flanges at both ends of the bobbin is made closer to the one end flange, and the primary coil is provided in the winding section having a narrow winding area. A secondary coil is wound around each winding section with a wide winding area.
And the joint between the leg end faces of the two E-shaped cores
Tran so to constitute a small transformer as a location
The transformer efficiency is high, and the transformer is lower in height than a conventional compact transformer in which a primary coil and a secondary coil are superposed and wound. Also, by making the core on the primary coil side conductive and the core on the secondary coil side insulating,
The charging of the core can be suppressed as much as possible, which is effective for preventing accidents due to leakage current of the core and suppressing transformer loss due to heat generation of the core.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a small transformer according to the present invention, which is partially cut away.

FIG. 2 is a vertical sectional side view of the small transformer.

FIG. 3 is an explanatory diagram showing a winding method of a coil.

FIG. 4 is a partially cutaway perspective view of a conventional small transformer.

FIG. 5 is a vertical sectional side view of a conventional small transformer.

[Explanation of symbols]

 Reference Signs List 50 bobbin 50a square tube portion 50b, 50c end flange 50d middle flange 51 first winding section 52 second winding section 53 primary coil 54 secondary coil 59, 60 E-shaped core

Claims (2)

(57) [Claims] 1. A bobbin in which a winding tubular portion is divided by a middle flange provided between both end flanges, a primary coil and a secondary coil wound on the winding tubular portion, the end flange and a middle coil. In a small transformer having a terminal pin provided on each of the flanges, and an EE-type core assembled by inserting the center leg of the E-type core into the winding tubular portion, the above-mentioned middle flange is located near one end flange of the bobbin. Forming
The primary coil is provided in the first winding section formed by the middle flange and the one end flange, and the second coil formed by the middle flange and the other end flange.
Each of the secondary coils is wound around a winding section, and one of the EE-shaped cores has a leg portion extending from one end flange to a position of a middle flange, and the other E-shaped core has a leg portion. A small transformer characterized in that the shaped core has a leg portion extending from the other end flange to the position of the middle flange. 2. The small transformer according to claim 1, wherein one E-shaped core is made of a conductive material and the other E-shaped core is made of an electrically insulating material.