JPH0650968Y2 - High frequency transformer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high frequency transformer used in various electronic devices.

2. Description of the Related Art In recent years, along with thinning of various electronic devices, there has been a strong demand for thinning of high frequency transformers.

As shown in FIGS. 5a and 5b, a conventional high-frequency transformer of this type has a coil 3 bonded to a terminal plate 5 having pin terminals 6.
The drum core 2 wound around is covered with the cap core 1 held by the shield case 4 which is screwed, and the inductance is changed by moving the cap core 1 up and down.

However, in the case of this type of structure, when the height of the shield case 4 is lowered. The stroke of the cap core 1 becomes smaller, and the variable range from the maximum inductance value when the cap core 1 and the drum core 2 are in close contact to the minimum inductance value when the cap core 1 and the drum core 2 are farthest apart is inevitably narrowed. It was something that ended up.

It is an object of the present invention to solve the above-mentioned conventional problems and to provide a high frequency transformer capable of sufficiently obtaining the variable range of the inductance even when the height of the device is reduced.

In order to solve the above problems, the high frequency transformer of the present invention is
A drum core around which a coil adhered to a terminal plate is wound is covered with a cap core having a hole having a diameter slightly larger than the outer diameter of the flange of the drum core on the ceiling so as to be vertically movable.

Action With the above configuration, the inductance can be greatly changed with a small stroke, and the thinning can be realized.

Embodiment Hereinafter, a high frequency transformer of an embodiment of the present invention will be described with reference to the drawings.

1 to 2, a terminal plate having pin terminals 15
Drum core 11 around which coil 12 adhered to 14 is wound, and screwed shield case connected to this terminal board 14.
The inductance is changed by moving up and down the cap core 10 having a hole 10a on the ceiling surface held by 12. The hole 10a provided on the ceiling surface of the cap core 10 has a diameter slightly larger than the outer diameter of the flange 11a of the drum core 11. Also,
A driver groove 16 is formed on the upper surface of the cap core 10 to move the cap core 10 up and down by screwing the cap core 10 into the screw portion 13a of the shield case 13.

FIG. 1 shows a state in which the cap core 10 is located at the lowest position and the drum core 11 around which the coil 12 is wound is largely covered, and FIG. 2 shows the minimum inductance. In FIG. 1, when the bottom of the driver groove 16 and the drum core 11 are aligned with each other, the cap core 10 and the drum core 11 are in the state of being closest to the closed magnetic path, and the maximum inductance is obtained. In addition, the hole 10a on the ceiling surface of the cap core 10 and the drum core 11
When the brim 11a is close, a small stroke of the cap core 10 can provide a large amount of change in inductance. Further, FIG. 2 shows a state in which the cap core 10 is moved to the uppermost position so as to cover a part of the drum core 11 around which the coil 12 is wound, and the cap core 10 and the drum core 11 have the most open magnetic path. Inductance is minimum in a state close to. FIG. 4 shows the relationship between the inductance and the stroke of the cap core 10 for the conventional product and the high frequency transformer of the present invention. From the relationship of H '<H, S'<S in FIGS. 1 and 5, in FIG. 4, the high frequency transformer of the present invention has a smaller cap core stroke than the conventional product. It can be confirmed that the same variable range of inductance can be obtained. Therefore, a shorter high-frequency transformer can obtain the same variable range of inductance as the conventional one, which greatly contributes to product thinning.

As described above, the high frequency transformer of the present invention is composed of the drum core and the cap core, and is bonded to the terminal board.
By making a hole having a diameter slightly larger than the outer diameter of the flange of the drum around which the coil is wound on the ceiling of the cap core and changing the inductance with a small stroke, it is possible to make the product thinner.

[Brief description of drawings]

1 and 2 are sectional views of a high frequency transformer according to the present invention, FIG. 3 is a perspective view of a cap core and a drum core used in the same high frequency transformer, and FIG. 4 is a high frequency in one embodiment of the present invention. Inductance characteristic diagrams of the transformer and the conventional high frequency transformer, and FIGS. 5A and 5B are sectional views of the conventional high frequency transformer including the drum core and the cap core. 10 …… Cap core, 10a …… Hole, 11 …… Drum core, 1
1a …… Tsuba, 12 …… Coil, 13 …… Shield case, 13a
...... Screw part, 14 ...... Terminal plate, 15 ...... Pin terminal.

Claims (1)

[Scope of utility model registration request] 1. A structure comprising a drum core around which a coil adhered to a terminal plate is wound, and a cap core provided with a hole having a diameter slightly larger than the outer diameter of the collar of the drum core on the ceiling surface so as to be vertically movable. High frequency transformer.