JP2006147978A - Small transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small transformer for high voltage whose temperature rise is suppressed for achieving the highest efficiency and whose height is reduced for flattening. <P>SOLUTION: The small transformer is provided with an E-I-E core composed of two E-shaped cores 42 and 43 of the same shape each having a central leg which is rectangular in cross section and right and left legs which are thinner than the central leg and are rectangular in cross section and an I-shaped core 44 which is square in cross section and coil elements A, B, C and D which are respectively fitted to the right and left legs of the E-shaped cores 42 and 43. Magnetic fluxes of the coil elements A and B are generated in reverse directions in the central leg of the E-shaped core 42 which is a common magnetic path and magnetic fluxes of the coil elements C and D are generated in reverse directions in the central leg of the E-shaped core 43 which is a common magnetic path. Also, magnetic fluxes of the coil elements A and C and the coil elements B and D are generated in reverse directions in the I-shaped core 44 which is a common magnetic path. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a small transformer used in electrical equipment such as a liquid crystal display and a flash discharge light emitter for photography.

There are various types of small transformers, an example of which is shown in FIG.
FIG. 9 shows a simplified configuration diagram of the small transformer 11 for high voltage output.
In this figure, 12 and 13 are E-shaped cores of the same shape made of a ferrite material, and these leg ends are joined and fixed to form a closed magnetic circuit.

The left legs 12a and 13a of the E-shaped cores 12 and 13 are equipped with a primary coil (input coil) 14 and a secondary coil (output coil) 15, and the right legs 12b and 13b have primary coils ( An input coil 16 and a secondary coil (output coil) 17 are provided.
The coils 14, 15, 16, and 17 are wound around the bobbin winding cylinder, and the left legs 12a and 13a and the right legs 12b and 13b of the E-shaped cores 12 and 13 are placed in the bobbin winding cylinder. Has been inserted.

As shown in the figure, the small transformer 11 has primary coils 14 and 16 connected in parallel, and secondary coils 15 and 17 connected in series.
Then, the primary coils 14 and 16 are supplied with a low alternating voltage, the magnetic flux Φ1 illustrated in the primary coil 14 is generated, and the magnetic flux Φ2 illustrated in the primary coil 16 is generated.
Thus, the induced voltages generated in each of the secondary coils 15 and 17 are added and output as a transformer output of several thousand volts.

  Since the above-described small transformer 11 has a structure in which coils are provided on the left and right legs of the E-type cores 12 and 13, the winding diameter of each coil can be reduced, and this is advantageous for flattening the small transformer. The transformer output can be subjected to a withstand voltage treatment separately on the left leg side and the right leg side of the E-shaped cores 12 and 13, so that a small transformer advantageous for a high voltage output withstand voltage process can be obtained.

  However, in this small transformer 11, the central legs 12c and 13c of the E-shaped cores 12 and 13 are common core magnetic path portions through which the magnetic fluxes Φ1 and Φ2 pass, and the magnetic fluxes Φ1 and Φ2 pass in the same direction through the core magnetic path portion. Therefore, there is an improvement in suppressing temperature rise and increasing efficiency.

  Further, the above-described small transformer 11 includes two transformers, and power is increased by connecting secondary coils of each transformer in series or in parallel. This is disadvantageous in terms of transformer production cost, installation space, and wiring, and is not preferable from the viewpoint of installation work efficiency.

JP 62-238613 A

  In view of the above circumstances, an object of the present invention is to provide a small transformer that increases efficiency as much as possible and increases power.

  In order to achieve the above-described object, in the present invention, as a first invention, a core portion including a plurality of coil bodies having primary and secondary coils and a magnetic flux of each coil body are commonly passed through each of the two coil bodies. In a small transformer having a ferrite core having each core magnetic path portion, the magnetic flux of one coil body passing through each core magnetic path portion and the magnetic flux of the other coil body are generated in opposite directions We propose a small transformer characterized by that.

  As a second invention, a coil body having a ferrite core having an E-I-E configuration in which an E-shaped core is connected to both sides of an I-shaped core, and primary and secondary coils provided on the left and right legs of each E-shaped core. A small transformer having a configuration in which magnetic fluxes of two coil bodies passing through the center leg of the E-shaped core and the I-shaped core are generated in opposite directions is proposed.

  As a third invention, there is proposed a small transformer characterized in that all or part of the primary coils of each of the coil bodies described above are connected in parallel in the small transformer of the first or second invention.

  According to a fourth invention, there is provided a small transformer characterized in that all or part of the secondary coils of each of the coil bodies described above are connected in series or in parallel in the small transformer of the first or second invention described above. suggest.

  In the small transformer of the first invention, a plurality of transformer parts are constituted by a plurality of coil bodies provided in the ferrite core, but the core magnetic path part for each of the two coil bodies has a magnetic flux of one coil body. Since the magnetic flux of the other coil body is generated in the opposite direction, the temperature rise is small and the transformer efficiency can be increased.

The small transformer of the second invention is a transformer using a ferrite core having an E-I-E configuration, and a coil body is provided on each of the left and right legs of each E-shaped core, and four transformer parts are provided. .
In the small transformer configured as described above, the center leg of the I-shaped core and each E-shaped core is a core magnetic path portion common to the two coil bodies.
And since the magnetic flux of one coil body and the magnetic flux of the other coil body generate | occur | produce in a reverse direction in this core magnetic path part, there is little temperature rise and it can improve transformer efficiency.

  The small transformer described above connects all or part of the primary coils of each coil body in parallel as in the third invention, and all or one of the secondary coils in each coil body as in the fourth invention. The transformer output can be increased by connecting the parts in series or in parallel.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a simplified configuration diagram of a small transformer 21 shown as an embodiment.
As shown in the figure, the small transformer 21 includes two E-shaped cores 22 and 23 having the same shape formed of a ferrite material, and an I-shaped core 24 having a rectangular cross section similarly formed of a ferrite material.

The E-shaped cores 22 and 23 and the I-shaped core 24 have a known structure. The E-shaped cores 22 and 23 are connected to both side surfaces of the I-shaped core 24 so as to be joined and fixed, and a closed magnetic circuit is formed. As a configuration to be formed.
Note that a sheet gap may be provided between the leg end surfaces of the E-shaped cores 22 and 23 and the I-shaped core 24.

The left leg 22a of the E-shaped core 22 has a coil body A composed of a primary coil 25 and a secondary coil 26, and the right leg 22b has a coil body composed of a primary coil 27 and a secondary coil 28. Each B is equipped.
Similarly, a coil body C composed of a primary coil 29 and a secondary coil 30 is arranged on the left leg 23a of the E-shaped core 23, and a coil body D composed of a primary coil 31 and a secondary coil 32 is arranged on the right leg thereof. Equipped.

  The coil bodies A to D described above are preliminarily wound around the winding cylinder part of each bobbin, and are equipped so that the leg parts of the E-shaped cores 22 and 23 are inserted into the winding cylinder part of the bobbin. However, the coil bodies A and C are wound in the same direction, the coil bodies B and D are wound in the opposite direction to the coil bodies A and C, and the magnetic fluxes ΦA, ΦB, ΦC and ΦD are generated as shown in the figure.

That is, the magnetic fluxes ΦA and ΦB of the coil bodies A and B are reversed with the central leg 22 c of the E-shaped core 22 as a common magnetic path, and similarly the magnetic fluxes ΦC and ΦD of the coil bodies C and D are the central leg of the E-shaped core 23. The direction is reversed with 23c as a common magnetic path.
The magnetic fluxes ΦA and ΦC of the coil bodies A and C and the magnetic fluxes ΦB and ΦD of the coil bodies B and D are generated in opposite directions with the I-shaped core 24 as a common magnetic path.

FIG. 2 shows a circuit example of the above-described transformer 21. As shown in the figure, in this circuit example, the primary coils 25, 27, 29, 31 of the coil bodies A to D are connected in parallel, and the secondary coils 26, 28 are connected. 30 and 32 are connected in series.
In the small transformer 21 connected in this way, each of the coil bodies A to D operates as a transformer unit, so that the induced voltage generated in the secondary coil of each coil body A to D is added, and the output of one coil body is added. 4 times the transformer output.

  The small transformer 21 is a small transformer having high efficiency with little temperature rise because the magnetic fluxes ΦA, ΦB, ΦC, and ΦD of the coil bodies A to D are reversed in the common magnetic path.

Next, examples of the present invention will be described.
FIG. 3 is a partially cutaway perspective view of a small transformer 41 showing an embodiment of the present invention, and FIG. 4 is a cross-sectional view of the small transformer.

The small transformer 41 includes a ferrite core having an E-I-E configuration and is operated in the same manner as the small transformer 21 shown in FIG.
However, the small transformer 41 is provided with a ferrite core shown in FIG. 5 in order to further reduce the height.

  Specifically, as can be seen from FIG. 5, two E-shaped cores 42 and 43 having the same shape and an I-shaped core 44 having a square cross section are provided. The left and right legs 42a, 42b and 43a of the E-shaped cores 42 and 43 are provided. , 43b have a thin cross-sectional shape with respect to the central legs 42c, 43c.

  In other words, the E-shaped core 42 will be described. The center leg 42c is formed so as to protrude from the center of the long yoke part 42d, and the center leg 42c has the same thickness as the yoke part 42d. It has a rectangular cross section.

The left and right legs 42a and 42b are formed so as to protrude from both end sides of the yoke portion 42d, and the left and right legs 42a and 42b are adapted to the coil winding diameter compared to the thickness of the yoke portion 42d. It is formed as a thin, oblong rectangular cross section.
Each of the left and right legs 42a and 42b has a cross-sectional area that is ½ that of the center leg 42c.
Although the E-shaped core 42 has been described, the other E-shaped core 43 has the same shape as the E-shaped core 42.

FIG. 6 shows a bobbin 45 that forms a coil body A by winding a coil.
A primary coil and a secondary coil are wound in advance on the winding cylindrical portion 45 a of the bobbin 45, and their winding start ends and winding ends are fixed to the terminal pins 46 and 47.
The terminal pin 46 is a low voltage terminal pin, and 47 is a high voltage terminal pin.

The coil body A configured as described above is assembled to the E-shaped core 42 such that the left leg 42a of the E-shaped core 42 is inserted into the winding cylindrical portion 45a.
The coil bodies B, C, and D are also formed by winding primary and secondary coils in advance on bobbins having the same configuration as above, and the coil bodies B, C, and D are formed on the right leg of the E-shaped core 42, the E-shaped core Assemble to 43 left and right legs in the same way as above.

The E-shaped cores 42 and 43 equipped with the coil bodies A to D are connected so that their leg end surfaces are joined to the I-shaped core 44 in the same manner as the small transformer 21 shown in FIG. The small transformer 41 shown in FIGS. 3 and 4 is formed.
If necessary, a sheet gap is provided between the leg end surfaces of the E-shaped cores 42 and 43 and the I-shaped core 44.

Further, as shown in FIG. 7, the small transformer 41 has magnetic fluxes ΦA, ΦB, ΦC, and ΦD opposite to the I-shaped core 44 and the central legs 42c and 43c of the E-shaped cores 42 and 43, which are common magnetic paths. The coil bodies A to D are formed so as to be oriented.
Therefore, a small transformer with a reduced height is obtained while reducing the temperature rise to increase efficiency.

8A and 8B show modifications of the core provided in the small transformer 41 described above.
The E-shaped cores 42 and 43 in the above embodiment have a rectangular cross section in which the left and right legs 42a, 42b, 43a and 43b are half the cross section of the central legs 42c and 43c. Since magnetic fluxes ΦA, ΦB, ΦC, and ΦD that are opposite to each other are generated in the legs 42c and 43c, the cross-sectional areas of the central legs 42c and 43c can be reduced.

  8A and 8B, the lateral widths of the central legs 52c and 53c are half that of the central legs 42c and 43c of the E-shaped cores 42 and 43 of the above embodiment. The left and right legs 52a and 52b and the central leg 52c have the same cross-sectional area, and the left and right legs 53a and 53b and the central leg 53c have the same cross-sectional area for the E-shaped core 53 as well.

  Even when the E-shaped cores 52 and 53 configured as described above and the I-shaped core 54 are connected to each other and a small transformer having the coil bodies A to D in the same manner as described above, the same efficiency as the small transformer 41 described above can be obtained. Experiments have confirmed that this is a small transformer.

  The small transformer implemented in this way is advantageous in that the transformer form in the left and right leg direction can be reduced in size according to the length of the central legs 52c and 53c shortened.

  Further, the small transformer of the present invention can be provided with terminal pins for inserting pins into the wiring board, not limited to the surface soldering terminal pins 46 and 47 shown in the above embodiment, and the number of primary coils connected in parallel. In addition, the number of secondary coils in series or in parallel can be arbitrarily determined, and the primary and secondary coils can be connected directly or by forming a wiring board.

    It can be used in electrical equipment such as liquid crystal displays and flash discharge light emitters.

It is a simplified lineblock diagram of a small transformer showing one embodiment of the present invention. It is a figure which shows the circuit example of the said small transformer. It is a partially cutaway perspective view of a small transformer showing an embodiment of the present invention. FIG. 4 is a cross-sectional view of the small transformer shown in FIG. 3. FIG. 4 is a perspective view showing an E-shaped core and an I-shaped core provided in the small transformer shown in FIG. 3. It is a perspective view which shows the bobbin of the coil body with which the small transformer shown in FIG. 3 was equipped. It is a figure which shows the path | route of the magnetic flux of the small transformer shown in FIG. FIG. 8A is a core front view showing a modification of the E-shaped core of the small transformer shown in FIG. 3, and FIG. 8B is a side view of the core. It is a simplified block diagram of a small transformer shown as a conventional example.

Explanation of symbols

21 Small transformers 22, 23 E-shaped cores 22a, 23a Left legs 22b, 23b Right legs 22c, 23c Center legs 24 I-shaped cores 25, 27, 29, 31 Primary coils 26, 28, 30, 32 Secondary coils A, B , C, D Coil body 41 Small transformer 42, 43 E core 44 I core 45 Bobbin

Claims (4)

In a small transformer having a ferrite core having a core portion having a plurality of coil bodies having primary and secondary coils, and each core magnetic path portion through which the magnetic flux of each coil body is passed in common for each of the two coil bodies,
A compact transformer characterized in that the magnetic flux of one coil body passing through each of the core magnetic path portions and the magnetic flux of the other coil body are generated in opposite directions. In a small transformer comprising a ferrite core having an E-I-E configuration in which an E-shaped core is connected to both sides of an I-shaped core, and a coil body having primary and secondary coils provided on the left and right legs of each E-shaped core. ,
A small transformer characterized in that the magnetic fluxes of two coil bodies passing through a central leg of an E-shaped core and an I-shaped core are generated in opposite directions. The small transformer according to claim 1 or 2,
A small transformer characterized in that all or part of the primary coils of each of the coil bodies described above are connected in parallel. The small transformer according to claim 1 or 2,
A small transformer, wherein all or part of the secondary coils of each of the coil bodies described above are connected in series or in parallel.

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