JPH02191308A - Ferrite core - Google Patents

Abstract

PURPOSE:To reduce a compound transformer in its size by performing protrusion formation of the inner-side surface of left and right legs, and performing curved formation of both side surfaces of central leg where each inner side surface of left and right legs oppose each other, and then connecting a central leg and left and right legs in one piece with a plate-shaped yoke which is narrower than the leg width of the central leg and wider than the leg width of left and right legs. CONSTITUTION:Both legs of a central leg 9S of a core 9 are expanded in a fan shape along the outer surface of coils 11 and 12 and the thickness of the central part of this central leg 9S is formed thinly. Then, the inside surface of left and right legs 9L and 9R which are placed symmetrically at both sides of the central leg 9S is protrudingly formed. Thus, the length 3l between outer surfaces of the coil in the left and right leg direction is reduced and the length 3d between the outer surfaces of the coil in the direction of core width is also reduced. Thus, the size of outer shape of a compound transformer can be reduced and an area for incorporating a transformer into an electrical appliance can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ferrite core of a composite transformer in which two transformers are integrally constructed.

Small electrical products such as flash discharge devices for photography, desktop calculators, and electric toys are becoming smaller day by day, and as a result, miniaturizing the electrical components incorporated in these electrical products has become a major issue. .

Nowadays, various means have been developed to save the installation area by integrally configuring two or more electrical components into one component.

The present invention was developed in view of the above-mentioned circumstances, and it is possible to integrally configure two transformers incorporated in a small electric product as a composite transformer, and to reduce the form of the composite transformer itself. We propose a ferrite core.

EMBODIMENT OF THE INVENTION Below, one embodiment of the present invention will be described along with the drawings to clarify the content of the invention.

FIG. 1 is a front view of a standard composite transformer, and FIG. 2 is a sectional view taken along line A--A in FIG. In this composite transformer, two E-shaped cores 1.2 of the same shape are joined at their leg end faces, and coils 3.4 are installed on the joined left legs IL, 2L and right leg lR12I, respectively.

The above E-type core 1.2 is a sintered product of ferrite powder, and the cross-sectional area of the central leg IS, 2g is twice the cross-sectional area of the corresponding left and right legs IL, IR, 2L, and 2R. The yokes LM and 2M of these cores 1 and 2 have the same cross-sectional area as the left and right legs.

Note that the cross-sectional areas of the left and right legs IL and IR or 2L and 2R are the same.

The composite transformer constructed as described above has an external size of approximately 1hXIQX1d. However, 1h is the height of the transformer, 1ρ is the length between the outer surfaces of the coil in the left and right leg direction,
1d is the length between the outer surfaces of the coil in the core width direction.

Therefore, this composite transformer is at least IQXld
of installation area is required.

Next, FIG. 3 is a perspective view of a ferrite core showing the first basic example of the present invention, FIG. 4 is a front view of a composite transformer using another core of the same shape as this core, and FIG. FIG. 4 is a sectional view taken along line B-B in FIG. 4;

The core 5 shown in these drawings is the above-mentioned E-type core 1.2.
The shape and cross-sectional area of the left and right legs 5L and 5R are the same as that of the E-shaped core 1.2.
is the same as

However, the leg width of the center leg 5S is set to be approximately twice the # width of the left and right legs 5L and 5R, and its cross-sectional area is the same as that of the center legs Is and 28 of the E-type cores 1 and 2. be.

In addition, the yoke 5M connecting the center leg 5S and the left and right legs 5L, 5R is formed into a quadrilateral plate shape, and as shown in the figure, the left and right legs 5L, SR are connected to the two sides of this plate-shaped yoke 5M. They are arranged symmetrically with the central leg 5S in between.

The plate thickness of this yoke 5M is the yoke I of the above E-type core 1.2.
It is formed considerably thinner than the wall thickness of M and 2M.

In addition, the coil 7 between the center leg 5S and the left and right legs 5L, 5R
．． The winding space 8 has the same size as the E-type core 1.2.

FIG. 4 shows a composite transformer constructed using the core 5 described above and another core 6 of the same shape. When the composite transformer is configured in this way, the height of the transformer becomes 2h<lh because the yoke 5M of the core 5 and the yoke 6M of the core 6 are formed thin.

In addition, the length between the coil outer surfaces in the core width direction is 2d = 1d, but the length 2Q between the coil outer surfaces in the left and right leg directions is less because the wall thickness of the center legs 5S and 6S (thickness in the left and right leg directions) is smaller. As a result, it becomes 2Q〈IQ.

Therefore, by using the core 5 of this basic example, the height 2h of the transformer and the length 2Q between the outer surfaces of the coils in the left and right leg directions are shortened, so that the external shape of the composite transformer is reduced.

FIG. 6 is a perspective view of a ferrite core showing a second basic example of the present invention, FIG. 7 is a longitudinal cross-sectional side view of a composite transformer using this core and another core of the same shape, and FIG. It is a sectional view taken along the line CC above.

The core 9 in this basic example has both ends of the central leg 9S connected to the coil 1.
It is enlarged in a fan shape along the outer surface of 1 and 12, and
The central portion of the central leg 9S is made thinner.

The left and right legs 9L and 9R, which are arranged symmetrically on both sides of the center leg 9S, have bulging inner surfaces. In addition,
Yoke 9M, coil winding space, center leg 9S and left and right legs 9
The cross-sectional areas of L and 9R are the same as the core 5 of the first basic example above.
is the same as

FIG. 7 shows a composite transformer constructed using the core 9 and a core 1° having the same shape as this core. Comparing this composite transformer with the above composite transformer of the first basic example, 3h
=2h, 3Q<2Q, 3d (2d.

That is, the length 3Q between the coil outer surfaces in the left and right leg direction is shortened by thinning the wall thickness of the center portion of the center legs 9S and 10S, and the length 3D between the coil outer surfaces in the core width direction is reduced.
is shortened by providing fan-shaped enlarged portions in the center legs 9S and IO3 and by forming a bulge on the inside of the left and right legs 9L, 9R110L, and IOR. That is, since the cross-sectional area of the central leg 9S increases by expanding both end portions of the central leg 9S into a fan shape, the leg l11 (length corresponding to 3d) of the central leg 9S can be shortened according to this increase. Furthermore, the width 3C of the left and right legs 9L and 9R can be reduced in accordance with the increased cross-sectional area due to the protruding surfaces formed on the inner surfaces.

As mentioned above, the external shape of the composite transformer of the second basic example is still smaller than that of the composite transformer of the first basic example.

FIG. 9 is a cross-sectional plan view of a ferrite core showing an embodiment of the present invention. The core 13 of this basic example has almost the same shape as the core 9 described above, except that this core 13 is formed at the four corners of the yoke 13M. It has a cutout portion 13P. By configuring it like this.

Since the terminal pin 14 to which the coil end is connected can be made to protrude from the notch 13P, the installation area is advantageously saved. In addition, in the same figure, 13L, 13R
are the left and right legs, and 13S is the center leg.

15 is a bobbin.

FIG. 10 is a cross-sectional view similar to FIG. 8 showing a first application example of the present invention.
The interval between the two is shortened.

With this configuration, the length 4Q between the outer surfaces of the coils 17 and 18 is shortened by the flesh portion of the central leg 16S.

FIG. 11 is a sectional view similar to FIG. 8 showing a second application example of the present invention, in which the core 19 of this application example has a cross-sectional area of the right leg 19R smaller than that of the left leg 19L. .

FIG. 12 is a sectional view similar to FIG. 8 showing a third application example of the present invention, and the core 2o of this application example is a modification of the second application example (FIG. 11). The right leg 2OR of this core 20 has a rectangular cross section, and its cross sectional area is smaller than that of the left leg 20L. Further, the side surface of the center leg 2O3 facing the right leg 20R has a planar shape.

In the core 19.2o of the above application example, the left leg constitutes a large capacity transformer, and the right leg constitutes a small capacity transformer. These composite transformers are effective when the oscillation transformer and trigger transformer of a flash discharge light emitting device are integrally constructed.

As described above, in the ferrite core according to the present invention, the width of the center leg is larger than the width of the left and right legs.

In addition, since the yoke connecting the left and right legs and the center leg is formed into a thin plate shape, the height of the transformer and the length between the outer surfaces of the coils in the direction of the left and right legs can be shortened.
In addition, the inner surfaces of the left and right legs are each bulged, and both side surfaces of the center leg facing the inner surfaces of the left and right legs are curved, so the length between the outer surfaces of the coil in the core width direction can be shortened.

Furthermore, the yoke is narrower than the width of the center leg and wider than the width of the left and right legs, and a notch is formed on the side of the yoke.
The terminal pin implanted in the bobbin can be pulled out from this notch, thereby reducing the external size of the composite transformer and saving the area for incorporating the transformer into the product.

In the above embodiment, the composite transformer was constructed using two ferrite cores with an E-shaped cross section in the left and right leg directions.
A similar composite transformer can be constructed by using one ferrite core and a planar core joined to the leg end face of this core.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a standard composite transformer, Fig. 2 is a sectional view taken along line A-A in Fig. 1, Fig. 3 is a perspective view of a ferrite core showing the first basic example, and Fig. 4 is a A front view of a composite transformer constructed using another core of the same shape as the core,
Fig. 5 is a sectional view taken along line B-B in Fig. 4, Fig. 6 is a perspective view of a ferrite core showing the second basic example, and Fig. 7 is constructed using another core of the same shape as the core. A vertical side view of the composite transformer, Figure 8 is a sectional view taken along the line C-C in Figure 7, Figure 9
The figure is a cross-sectional plan view of a ferrite core showing an embodiment of the present invention, FIG. 10 is a cross-sectional view similar to FIG. 8 showing a first application example, and FIG. 11 is a cross-sectional view similar to FIG. 8 showing a second application example. Figure, 12th
The figure is a sectional view similar to FIG. 8 showing a third application example. 5.6...Core 5L, 6L...Left leg 5R16R...Right leg 5S, 6S...Central leg 7.8...Coil 9.10...Core 9L, IOL...Left Leg 9R1IOR...Right leg 9S, 10S...Central leg 11.12...Coil 13...Core 13L...Left leg 3R...Right leg 3S...Central leg 6...Core 6L...Left leg 6R...Right leg 6S...Center leg 9...Core 9L...Left leg 9R...Right leg 9S...Center leg 0...Core OL... Left leg OR...Right leg OS...Central leg Fig. Fig. Fig. 10 Fig. Fig. I Fig. 12

Claims (1)

[Claims] In a tripod-shaped ferrite core having a central leg and left and right legs, the left and right legs are formed into a quadrilateral cross section, the center leg is formed into a rectangular cross section with a longer diameter than the width of the left and right legs, and the inner surfaces of the left and right legs are bulged. At the same time, both side surfaces of the center leg, where the inner surfaces of the left and right legs face each other, are curved, and the center leg and the left and right legs are integrally connected by a plate-shaped yoke that is narrower than the width of the center leg and wider than the width of the left and right legs. A ferrite core.