JPH04184908A - Flyback transformer - Google Patents

Abstract

PURPOSE:To obtain a high quality flyback transformer, by constituting a hole part which is not opened outward, in a gap spacer or the abutting part of part cores, and forming leakage magnetic flux which leaks outward. CONSTITUTION:When an alternating current is made to flow in the primary coil of an winding 3, magnetic flux lines 9 forming closed loop are generated in a circuit constituted of an U-shaped part cores 2a, 2b and a gap spacer 6. Said magnetic flux lines 9 alternate with the same period as the current flowing through the primary coil. In the state that the gap spacer is not inserted, the reluctance of the magnetic flux lines 9 is determined by the dimension of a gap 5. When the spacer 6 is inserted, the relutance is given by formula I where mu1 is the permeability of the U-shaped part core, mu2 is the permeability of the gap spacer, and S2 is the sectional area of the gap spacer vertical to the magnetic path. When the number of turns of the primary coil is N1, and an alternating current I is made to flow through said coil, the generated magnetic flux PHI and the average magnetic flux density B are shown by formula II. Thereby the magnetic saturation of a flyback transformer 1 can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a flyback transformer that is used in television fan receivers, etc., in which wires are wound around a core made by abutting partial cores such as U-shaped ferrite cores. It is something.

[Conventional technology]

Figure 5 is a partially cutaway front view of a conventional flyback transformer.
) is a pair of U-shaped partial cores (2a
) = core (2) formed by abutting (2b), a winding part (3) applied to this core (2), a gap spacer (6) inserted into the gap (5) of the abutting part (4) , and a U-shaped clamp (7) for fixing these.

The winding section (3) consists of a secondary coil, a high-voltage secondary coil, and a low-voltage tertiary coil.The high-voltage secondary coil is for supplying the anode voltage and focus voltage of the cathode ray tube, and has several thousand turns of winding. has. The low-voltage tertiary coil is used to supply power to the heater of the cathode ray tube, DC voltage to the video circuit, integrated circuit, and the like.

The above flyback transformer (1) is constructed by inserting U-shaped partial cores (2a) and (2b) made of ferrite into a pre-wound wire winding (3).
), gap (5) of butt part (4) of (2b)
Insert the gap spacer (6) into. The flyback transformer (1) thus assembled is manufactured by being fixed with a mouth-shaped elastic metal clamp (7).

Such a flyback transformer (1) is designed to provide a high output of several tens of W to over a hundred and several tens of W, depending on the deflection angle, screen size, voltage, etc. of the television receiver. Since this flyback transformer (1) handles a large amount of electric power, a magnetic flux of 2000 to 2500 Gauss is formed inside the core (2). Therefore, in order to prevent magnetic saturation of the core (2), a gap spacer (6) made of a plastic plate or the like is used.

[Problem to be solved by the invention]

Since the conventional flyback transformer is configured as described above, a large amount of leakage magnetic flux leaks from the gap spacer (6) to the outside, affecting the characteristics of other electronic components such as the deflection yoke, and also preventing this leakage. There was a problem in that the magnetic flux interfered with the coil of the winding portion (3), increasing copper loss.

This invention was made to solve the above-mentioned problems, and it is possible to reduce the leakage magnetic flux leaking to the outside from the flyback transformer, and to reduce the copper loss due to interference with the coil in the winding section. The purpose is to provide a flyback transformer that can perform

(Means for solving problems) This invention is the following flyback transformer.

(1) In a flyback transformer having a core and a winding portion formed by butting together partial cores made of magnetic material, 1
A flyback transformer in which a gap spacer made of a magnetic material and having a hole that does not open to the outside is interposed between the abutting portions of the partial cores.

(2) A core formed by abutting partial cores made of magnetic material, and a magnetic material at the abutting portion of the partial core having a winding portion,
A flyback transformer with a hole that does not open to the outside.

[Function] The flyback transformer according to the present invention uses a magnetic material having holes as a gap spacer, thereby achieving the following effects.
The leakage magnetic flux is reduced, and the influence of the leakage magnetic flux on electronic components such as the deflection yoke is reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a partially cutaway front view of a flyback transformer of one embodiment, and FIG. 2 is a perspective view of a gap spacer. In FIG. 1, the same reference numerals as in FIG. 5 indicate the same or corresponding parts. The flyback transformer (1) in Figure 5 is almost the same as the one in Figure 5, but with a gap spacer (
As shown in Fig. 2, 6) is made of a ferrite plate having a hole (8) in the center that does not open to the outside, and the butt part (4) of the partial cores (2a) and (2b) also made of ferrite. It is interposed in the gap (5). (9) shows that when current is passed through the -order coil of winding section (3),
) are the magnetic flux lines generated at

Next, when an alternating current is passed through the secondary coil of the first winding section (3), which will explain the operation, a U-shaped partial core (2a) is formed.
= A closed curve magnetic flux line (9) is generated in the circuit composed of (2b) and the gap spacer (6).

These magnetic flux lines (9) alternate with the same period as the current flowing through the -order coil. Without the gap spacer (6), the magnetic resistance of the magnetic flux lines (9) is determined by the size of the gap (5).

Next, when inserting a gap spacer (6), the area of the cross section perpendicular to the magnetic path of the U-shaped partial cores (2a) and (2b) is S, the average magnetic path length is ρ, and the interval between the gaps (5) is Let d be the magnetic resistance R of this magnetic circuit.

It can be expressed as

here.

μm: Magnetic permeability of the U-shaped partial core μ3: Magnetic permeability of the gap spacer S3: Cross-sectional area perpendicular to the magnetic path of the gap spacer Generally, if the magnetic permeability of the U-shaped partial core is larger than the magnetic permeability of the gap spacer, .

becomes.

Therefore, when the number of turns of the -order coil is N1, and an alternating current is passed through it, the magnetic flux Φ generated is as follows from the following relational expression, and the average magnetic flux density B in the core is.

becomes.

Therefore, by providing a hole (8) in the gap spacer (6) and changing its cross-sectional area S3, magnetic saturation of the flyback transformer (1) consisting of the U-shaped partial cores (2a) and (2b) is prevented. can do.

In addition, this gap spacer (6) is attached to the partial core (2a).
, (2b) and by changing the magnetic permeability, magnetic saturation can be controlled more easily.

FIG. 3 is a partially cutaway front view of a flyback transformer according to another embodiment, and FIG. 4 is a perspective view of a partial core thereof.

In this embodiment, the partial cores (2a) and (2b) are formed of ferrite into a U-shape, and the abutting portion (4) thereof is annular, with a hole (8) formed in the center.

These partial cores (2a) and (2b) are connected to the butt part (4)
A core (2) is formed by abutting the two parts without forming a gap, and a hole (8) that does not open to the outside is formed in the center of the abutting part (4), producing the same effect as in the previous embodiment.

In addition, in the above embodiment, the partial core (2a) is U-shaped.

Although the example in which the gap (5) or the hole (8) is provided in both abutting portions (4) in (2b) has been described, the same effect can be obtained even if the gap (5) or the hole (8) is provided in only one of the abutting portions (4).

Further, in the above embodiment, as a typical example of a flyback transformer, a partial core (2a) made of U-shaped ferrite,
Although the example of the combination (2b) is explained, it goes without saying that it is also effective to combine magnetic material partial cores of other shapes, such as a combination of a U-shaped partial core and/or a single-shaped partial core. .

〔Effect of the invention〕

As described above, according to the present invention, by providing the gap spacer or the abutting portion of the partial core with a hole that does not open to the outside, leakage magnetic flux leaking to the outside is reduced, and a high-quality flyback transformer can be obtained. It has the effect of

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of a flyback transformer according to one embodiment of the present invention, FIG. 2 is a perspective view of the gap spacer, and FIG. 3 is a partially cutaway view of a flyback transformer according to another embodiment. FIG. 4 is a perspective view of a partial core thereof, and FIG. 5 is a partially cut-away front view of a conventional flyback transformer. In each figure, the same reference numerals indicate the same or corresponding parts 1, (1
) is the flyback transformer, (2) is the core, (2a). (2b) is a partial core, (3) is a winding part, (4) is a butt part, (5) is a gap, (6) is a gap spacer, (
7) is a clamp, (8) is a hole, and (9) is a magnetic flux line.

Claims (2)

[Claims] (1) In a flyback transformer having a core and a winding portion formed by butting together partial cores made of magnetic material,
A flyback transformer characterized in that a gap spacer made of a magnetic material and having a hole that does not open to the outside is interposed between the abutting portions of the partial cores. (2) A core formed by abutting partial cores made of magnetic material, and a magnetic material at the abutting portion of the partial core having a winding portion,
A flyback transformer characterized by having a hole that does not open to the outside.