JP2600000Y2 - Flyback 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 flyback transformer used for a television receiver or a display device.

[0002]

2. Description of the Related Art FIG. 5 shows a sectional structure of a conventional flyback transformer. In the figure, the flyback transformer has a UU-type core 1 inserted into a core insertion hole 10 of a transformer coil 5 composed of a low-voltage coil 2 and a high-voltage coil 3 and is housed in a case 4 in this state, and is made of epoxy or the like. Embedded in the casting resin 6 of FIG. The core 1
Has two U-shaped cores 7 and 8, each magnetic leg 7a, 7b and 8
a, 8b are opposed to each other, and each magnetic leg 7a,
Gap members 9a and 9b for adjusting the inductance of the coil are interposed between 7b and 8a and 8b. The entire core 1 including the U-shaped cores 7 and 8 is formed of the same core material.

The core 1 forms a closed magnetic path by an insertion magnetic path portion A inserted into the core insertion hole 10 of the transformer coil 5 and an outer magnetic path portion B extending outside the transformer coil 5. I have.

In the flyback transformer having the above configuration, when the flyback transformer is driven, the transformer coil 5 and the core 1 generate heat. At this time, the insertion magnetic path portion A of the core 1 inserted into the transformer coil 5 Is
Since the heat is less radiated than the outer magnetic path portion B located outside the transformer coil 5, the heat tends to be trapped. Therefore,
As shown in the graph of FIG. 4, the temperature of the inserted magnetic path portion A is higher than that of the outer magnetic path portion B.

In order to reduce the heat generated by the flyback transformer, it is necessary to keep the temperature rise of the core 1 small. As a first measure in this case, as a first measure, the core diameter is increased, or the core 1 is heated. Is formed of a high quality core material having a small core loss, thereby suppressing the temperature rise of the core 1.

[0006]

However, when the core diameter is increased as in the first measure, the core 1
However, there is a problem in that the entire core is increased in size and weight, and as a result, the flyback transformer is also increased in size and weight.

Further, when the core 1 is formed of a good quality core material as in the case of the second measure, the temperature rise of the core can be suppressed small in this case as well, but the high quality core material is expensive. However, there has been a problem that the material cost of the core 1 is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a flyback transformer which is low in cost and small in size, and which suppresses temperature rise of the core. To provide.

[0009]

The present invention is configured as follows to achieve the above object. That is, in the present invention, the core is inserted into the core insertion hole of the transformer coil, and the core includes an insertion magnetic path portion inserted into the core insertion hole and an outer magnetic path portion extending outside the transformer coil. In a flyback transformer having a closed magnetic path, the insertion magnetic path portion of the core is formed of a material having a smaller core loss than the outer magnetic path portion.

[0010]

When the flyback transformer is driven, the transformer coil and the core generate heat, but the inserted magnetic path portion of the core inside the transformer coil is formed of a high quality material having a smaller core loss than the outer magnetic path portion. Therefore, the temperature rise of the insertion magnetic path portion, which is difficult to dissipate heat, is suppressed to a small level, and can be made substantially equal to the temperature rise of the outer magnetic path portion of the core. As a result, heat generation of the flyback transformer is suppressed.

Since a high-cost, high-quality material is used only for the insertion magnetic path portion, the core can be provided at low cost, and it is not necessary to increase the core diameter. Therefore, the core can be downsized, and the flyback transformer can be downsized. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the flyback transformer according to the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same reference numerals are given to the same names as those in the conventional example, and the duplicated description thereof will be omitted.

FIG. 1 shows a partial configuration of a first embodiment of a flyback transformer according to the present invention. The difference between this embodiment and the conventional example is that in the conventional example, the cores 1 are all formed of the same core material.
Insertion magnetic path portion A of U-shaped core 1, that is, U-shaped cores 7, 8
The hatched portions corresponding to the magnetic legs 7b and 8b are formed using a high quality core material having a smaller core loss than the outer magnetic path portion B. Other configurations are the same as those of the conventional example.

In this embodiment, the insertion magnetic path portion A is 5.0 mw
/ G of the core material, and the outer magnetic path portion B is formed of a 7.5 mw / g core material having a larger core loss.

In the present embodiment having the above-described structure, the insertion magnetic path portion A of the core 1 in the transformer coil 5 where heat is hardly radiated is formed using a core material having a small core loss. Even when the transformer coil 5 and the core 1 generate heat by driving the flyback transformer, as shown in the graph of FIG. 3, the temperature rise of the insertion magnetic path portion A can be suppressed small, and the core material is formed of a core material having a large core loss. The temperature can be increased in the same manner as the outer magnetic path portion B. As described above, since the temperature rise of the insertion magnetic path portion A does not increase as in the conventional example, the heat generation of the flyback transformer is suppressed to a small value.

According to this embodiment, it is not necessary to increase the core diameter, so that the core can be made smaller and lighter than the first measure, and the flyback transformer can be made smaller and lighter.

Further, since a high quality but high cost core material is not used for the entire core as in the second measure, but is used only for the insertion magnetic path portion A which is a part of the core, the core material is expensive. Cost can be reduced.

Further, by combining the magnitude of the core loss of the core material forming the insertion magnetic path portion A and the outer magnetic path portion B of the core 1, the core 1 corresponding to the drive frequency of the flyback transformer can be appropriately provided. That is, the higher the drive frequency of the flyback transformer, the higher the heat generation of the transformer coil 5 and the core 1. Therefore, in order to reduce the heat of the flyback transformer, the higher the drive frequency, the smaller the material of the core 1 with the smaller core loss. Need to be something.

For example, the core material is made of X having a small core loss.
If the drive frequency is high, the insertion magnetic path portion A is replaced with the X product, and the outer magnetic path portion B is used.
When the driving frequency is medium, the insertion magnetic path portion A is made of a Y product, and the outer magnetic path portion B is made of a Z product. Suitable cores can be provided.

FIG. 2 shows a partial configuration of a second embodiment according to the present invention. In the first embodiment, the core 1
Uses a UU-shaped core composed of U-shaped cores 7 and 8, but in this embodiment, a UI-shaped core composed of a U-shaped core 12 and an I-shaped core 11 is used. The insertion magnetic path portion A of the UI-shaped core, that is, the magnetic leg 12b of the U-shaped core 12 is formed using a core material having a smaller core loss than the outer magnetic path portion B.

Also in this embodiment, since only the insertion magnetic path portion A of the core 1 is made of a high-quality core material, the cost of the core 1 is reduced and the size of the core 1 is reduced. An effect similar to that of the first embodiment is obtained.

The present invention is not limited to the above embodiment, but can take various embodiments. For example, in each of the above-described embodiments, two types of core materials are used, one for the insertion magnetic path portion A and the other for the outer magnetic path portion B. However, the core is distributed and formed using three or more types of core materials. Alternatively, the temperature rise of the core may be effectively suppressed.

[0023]

[Effect of the Invention] In the present invention, the insertion coil portion of the core that is difficult to dissipate heat is formed of a material having a smaller core loss than the outer magnetic path portion of the core that dissipates heat easily. Even if heat is generated in the core, the temperature rise in the insertion magnetic path portion of the core is suppressed to be as small as that in the outer magnetic path portion, and the heat generation of the entire flyback transformer can be reduced.

Also, in the present invention, it is not necessary to increase the core diameter, so that the core is made smaller and lighter than in the case where the core temperature is suppressed by increasing the core diameter. Is reduced in size and weight.

Further, in the present invention, since the insertion magnetic path portion is formed of a high quality core material having a smaller core loss than the outer magnetic path portion, the entire core is formed of a high quality core material to suppress the temperature rise. The cost of the core can be reduced compared to what is intended.

[Brief description of the drawings]

FIG. 1 is a partial configuration diagram showing a first embodiment of a flyback transformer according to the present invention.

FIG. 2 is a partial configuration diagram showing a second embodiment according to the present invention.

FIG. 3 is a graph showing an aspect of a temperature rise of a core portion in each embodiment shown in FIGS. 1 and 2.

FIG. 4 is a graph showing a mode of temperature rise of a core portion in a conventional example.

FIG. 5 is an explanatory diagram showing a conventional example of a flyback transformer.

[Explanation of symbols]

 1 core 5 transformer coil A insertion magnetic path B outer magnetic path

Claims (1)

(57) [Scope of request for utility model registration] A core is inserted into a core insertion hole of a transformer coil, and the core is closed by an insertion magnetic path part inserted into the core insertion hole and an outer magnetic path part protruding outside the transformer coil. A flyback transformer having a path, wherein the insertion magnetic path portion of the core is formed of a material having a smaller core loss than the outer magnetic path portion.