JP2000277360A - Transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transformer whose width and thickness can be reduced. SOLUTION: This transformer uses a rod-structured core for a coil winding magnetic circuit core 8 which is inserted into a bobbin 1, and a C-shaped core as an external magnetic circuit core 10 attached to the outside of the bobbin 1. Both cores 8 and 10 constitute a magnetic circuit, and spacers 9a and 9b are interposed between the cores 8 and 10. By using a rod-structured core as the core 8, the cross-sectional area of a coil wound part magnetic circuit portion can be made smaller and thin, and hence the transformer can be made narrower in width and thinner in thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer, and more particularly to a technique for reducing the size and improving magnetic coupling of an inverter transformer used for an inverter power supply of a cathode ray tube for a backlight source of a liquid crystal display.

[0002]

2. Description of the Related Art A liquid crystal display unit of a laptop or notebook type personal computer uses a side light type backlight, and the overall size of a liquid crystal panel, a light guide plate, an inverter power supply unit, etc. is reduced and the thickness is reduced. The company is trying to make it smaller and thinner, which is the selling point of its products.

Here, in order to reduce the size and thickness of the inverter power supply, it is essential to reduce the width and thickness of the inverter transformer used for the inverter power supply. In addition, since a battery is used as a driving power source, there is a strong demand for higher efficiency of the inverter power source. Inverter power supplies have been made smaller and thinner by surface mounting, and transformers have also been made thinner by surface mounting structures.

FIG. 6 is an exploded perspective view of a transformer using an EE type ferrite core, and FIG. 7 is a perspective view of the transformer after assembly. As shown in FIG. 6, this transformer is composed of a divided winding bobbin 1 and an insulating cover 1 covering the divided winding bobbin 1.
1. It has a pair of EE cores 12a and 12b. In the divided winding bobbin 1, reference numeral 4 denotes a core insertion opening, 5 denotes a primary coil, and 6 denotes a secondary coil. A pair of EE cores 12a,
12b are inserted from both ends of the core insertion opening 4 so as to face each other. In the assembled state shown in FIG. 7, the tips of the legs are joined.

[0005]

In order to reduce the thickness of the transformer, it is necessary to reduce the cross-sectional area of the coil winding magnetic circuit. However, the EE-type ferrite core and the EI-type ferrite core cannot make the cross-sectional area of the coil winding magnetic circuit small and thin due to their shapes. There is a problem that it is not possible to meet the demands for narrowing and thinning.

The present invention has been made in view of such a background, and an object of the present invention is to provide a transformer that can be narrowed and thinned.

[0007]

In order to achieve the above object, a first means is to provide a transformer including a bobbin, a coil wound around the bobbin, and a magnetic core, the coil being inserted into the bobbin. The present invention is characterized in that a rod-shaped core is used as a winding part magnetic circuit core, a U-shaped core is used as an external magnetic circuit core mounted on the outside of the bobbin, and a magnetic circuit is constituted by both cores.

In order to achieve the above object, a second means is the first means, wherein a spacer is interposed between the coil winding part magnetic circuit core and the external magnetic circuit core. Things.

In order to achieve the above object, the third means is characterized in that, in the first means, a magnetic material having a high saturation magnetic flux density is used for a coil winding magnetic circuit core. is there.

As described above, according to the present invention, a rod-shaped core is used as a coil winding magnetic circuit core inserted into a bobbin, and a U-shaped core is used as an external magnetic circuit core mounted outside the bobbin. The magnetic circuit is composed of a core, and by using a rod-shaped core as the coil winding part magnetic circuit core, the cross-sectional area of the coil winding part magnetic circuit can be reduced and thinned.
The thickness can be reduced.

[0011] Further, since the spacer is interposed between the coil winding part magnetic circuit core and the external magnetic circuit core, the magnetic resistance in the vertical direction is increased on the side surface of the coil winding part magnetic circuit core, and the magnetic flux is reduced. The coil winding portion is transmitted from the side of the magnetic circuit core to the external magnetic circuit core.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an external perspective view of a bobbin of a transformer, FIG. 2 is an exploded perspective view of a transformer according to an embodiment of the present invention,
FIG. 3 is a perspective view of the transformer after assembly, FIG. 4 is an external perspective view showing a state before joining of a coil winding part magnetic circuit core and an external magnetic circuit core, and FIG. FIG.

As shown in FIG. 1, the divided bobbin 1 has a plurality of primary coil winding grooves 2a, 2b and a plurality of secondary coil winding grooves 3a, 3b, 3c, 3d, 3e, 3f, 3g. A core insertion hole 4 is formed in the outer peripheral portion, and is provided with a coil winding part magnetic circuit core described later.

As shown in FIG. 2, the primary coil winding grooves 2a,
The primary coil 5 is wound around 2b, and the secondary coil 6 is wound around the secondary coil winding grooves 3a to 3g. The outer periphery of the wound bobbin 1 after winding the coil is covered with an insulating tape 7 to be insulated from the outside.

In the present invention, the coil winding magnetic circuit core 8
A rod-shaped (rectangular parallelepiped) core is used, and a U-shaped core is used as the external magnetic circuit core 10. The external magnetic circuit core 10 includes a rod-shaped portion 10a and holding portions 10b and 10c formed at both ends thereof at right angles to the rod-shaped portion 10a.
The end faces of the holding portions 10b and 10c are brought into contact with both end portions of one side of the coil winding magnetic circuit core 8 (see FIG. 5).

Spacers 9a and 9b are provided on the contact surface between the coil winding magnetic circuit core 8 and the external magnetic circuit core 10.
(See FIGS. 2 and 4). This spacer 9a,
9b, the magnetic resistance in the direction perpendicular to the side surface of the coil winding part magnetic circuit core 8 is increased, and the magnetic flux exits from the side surface of the coil winding part magnetic circuit core 8 and the external magnetic circuit core 1
It is transmitted to 0.

At the time of assembling the transformer, the primary coil 5 and the secondary coil 6 are wound around the primary coil winding grooves 2a and 2b and the secondary coil winding grooves 3a to 3g of the divided winding bobbin 1, respectively. Is coated. Then, a rod-shaped coil winding part magnetic circuit core 8 is inserted from the core insertion opening 4, while an external magnetic circuit core 10 is mounted outside the split winding bobbin 1.

When mounting the external magnetic circuit core 10,
The external magnetic circuit core 10 is mounted such that the outer surfaces of both outer flange portions of the divided winding bobbin 1 are sandwiched between the inner surfaces of both holding portions 10b and 10c of the external magnetic circuit core 10. In this state, both ends of one side of the coil winding magnetic circuit core 8 via the spacers 9a and 9b,
A magnetic circuit is formed by abutting the end faces of both holding portions 10b and 10c of the external magnetic circuit core 10 (see FIG. 3).

As described above, according to the present embodiment,
Since a rod-shaped core is used as the coil winding magnetic circuit core 8, the cross-sectional area of the coil winding magnetic circuit can be reduced, and the width and thickness of the transformer can be reduced. Further, by using a closed magnetic circuit, the magnetic coupling between the primary coil 5 and the secondary coil 6 can be improved.

[0021]

According to the first and third aspects of the present invention, a rod-shaped core made of a material having a high saturation magnetic flux density is used as the magnetic circuit core of the coil winding portion inserted into the bobbin, and is mounted outside the bobbin. A U-shaped core is used as the external magnetic circuit core, and a magnetic circuit is formed by both cores.By using a rod-shaped core as the coil winding magnetic circuit core, the cross-sectional area of the coil winding magnetic circuit is reduced and It is possible to make the transformer thinner, so that the transformer can be made narrower and thinner.

According to the second aspect of the present invention, since the spacer is interposed between the coil winding part magnetic circuit core and the external magnetic circuit core, the spacer is perpendicular to the side surface of the coil winding part magnetic circuit core. The magnetic resistance can be increased so that the magnetic flux exits from the side surface of the coil winding part magnetic circuit core and is transmitted to the external magnetic circuit core.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a bobbin of a transformer.

FIG. 2 is an exploded perspective view of a transformer according to the embodiment of the present invention.

FIG. 3 is an external perspective view of the assembled transformer.

FIG. 4 is an external perspective view showing a state before joining of a coil winding part magnetic circuit core and an external magnetic circuit core.

FIG. 5 is an external perspective view showing a state after the bonding.

FIG. 6 is an exploded perspective view of a transformer using an EE type ferrite core.

FIG. 7 is an external perspective view of the assembled transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Split winding bobbin 2 Primary coil winding groove 3 Secondary coil winding groove 4 Core insertion port 5 Primary coil 6 Secondary coil 7 Insulating tape 8 Coil winding part magnetic circuit core 9 Spacer 10 External magnetic circuit core

Claims (3)

[Claims] 1. A transformer comprising a bobbin, a coil wound around the bobbin, and a magnetic material core, wherein a rod-shaped core is used as a coil winding magnetic circuit core inserted into the bobbin, and mounted outside the bobbin. A transformer characterized in that a U-shaped core is used as an external magnetic circuit core and a magnetic circuit is formed by both cores. 2. The transformer according to claim 1, wherein a spacer is interposed between the coil winding part magnetic circuit core and the external magnetic circuit core. 3. The transformer according to claim 1, wherein a magnetic material having a high saturation magnetic flux density is used for a coil winding part magnetic circuit core.