JPH0238417Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a current-controlled variable inductor used in an electronic tuning circuit such as a car tuner.

[Prior art and its problems]

FIG. 4 is an explanatory diagram of a conventional current controlled variable inductor, which was filed by the present applicant as Japanese Patent Application No. 14822/1982.

A control coil 2 is wound around the first core 1, and a second core 5 around which a tuning coil 4 is wound is inserted into a hollow portion 3 provided in the winding portion. Furthermore, the first core 1 is covered with a pot-shaped third core 6. 7 is the first core 1 and the second core 5
is a base on which is placed and the third core 6 is fitted, and 8 is a terminal pin. The magnetic path by the control coil 2 extends from the first core 1 to the third core 6 as represented by the dotted line 9, and the magnetic path by the tuning coil 4 extends from the second core 5 to the third core as represented by the dotted line 10. However, both magnetic paths 9 and 10 overlap most in the winding portion 11 of the second core 5. By passing a direct current or a low frequency current through the control coil 2 to change the magnetic flux density, the effective magnetic permeability of the second core 5 can be controlled and the inductance of the tuned coil 4 can be changed.

However, such a configuration includes one tuning coil, and does not change the inductance of a plurality of tuning coils at the same time. In electronic tuning circuits, there are cases where multiple tuning coils are combined to form a transformer, etc. In this case, it is necessary to simultaneously change the characteristics of the tuning coils to adjust the overall characteristics. A current-controlled variable inductor that includes a tuning coil has never existed.

〔the purpose〕

An object of the present invention is to provide a current-controlled variable inductor that has a plurality of tuned coils and whose characteristics can be adjusted simultaneously.

[Technical means to solve problems]

In the current-controlled variable inductor of the present invention, a hollow part is provided in the winding part of the first core around which the control coil is wound, and a plurality of tuning coils are connected to one or more second cores in the hollow part. The winding part of the second core and the winding part of the first core are inserted in parallel with each other, and the winding part of the first core is inserted into the pot-shaped first core. The second core is inserted perpendicularly to the bottom surface of the second core, and the magnetic paths of the control coil and the tuning coil overlap at the winding portion of the second core.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the current controlled variable inductor of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is an explanatory longitudinal cross-sectional view, and FIG. 2 is an exploded perspective view showing the coils removed.

In FIGS. 1 and 2, 20 is the first core;
21A and 21B are second cores, 22 is a third core, and 23 is a fourth core, all of which are made of ferrite, which is a magnetic material. The first core 20 and the third
The core 22 is for low frequency, the second core 21A, 21
B and the fourth core 23 are made of high-frequency ferrite suitable for use at the frequency of the current flowing in the tuning coil, which will be described later. The base 34 is made of synthetic resin.

The winding portion 24 of the first core 20 having circular flanges at both ends is provided with a hollow portion 25 having a circular cross section, the opening of which is located in the lower collar 26 . Winding part 24
A control coil 27 is wound around. A pot-shaped fourth core 23 is fitted into the hollow portion 25 .

A tuning coil 29A is wound around the winding portion 28A of the second core 21A, which has circular flanges at both ends.
Another tuning coil 29B is wound around the winding portion 28B of the second core 21B having the same shape. core 2
1A and core 21B have one side of the tsuba in contact with each other,
The winding part 28A and the winding part 28B are inserted into the hollow part 25 so as to be covered by the fourth core 23 and parallel to the winding part 24.

Furthermore, the first core 20 has a pot-shaped third core 22.
The winding part 24 is inserted into the bottom surface 32 of the winding part 24.
perpendicular to The third core 22 is a control coil 27
A magnetic path 44 is formed inside and serves to prevent its divergence.

The circular base 34 has a circular protrusion 3 at the center of the top surface.
5 is provided, and the second core 21B of the hole 36
The protrusion 37 of is fitted. Control coil 27 on the bottom
Terminal pins 38 are implanted for connecting the lead wires of the tuning coils 29A and 29B. Projection 3
A second core 21B is fixed on top of the second core 5, and the other cores are all supported on the base 34.

Note that the upper flange 33 of the first core 20 and the third core 2
2, the inner surface 39 of the hollow part 25 and the fourth core 23, the bottom surface 31 of the fourth core 23 and the upper collar 30 of the second core 21A, and the lower collar 4 of the second core 21A.
0 and the upper flange 41 of the second core 21B are in contact with each other, and the inner surface 4 of the first core 20 and the third core 22
2, the second cores 21A, 21B and the fourth core 2
Although there is a slight gap between the inner surfaces 43 of 3, a Mylar film or the like may be sandwiched between the contact portion and the gap in order to improve the stability of properties and physical strength.

In the variable inductor of the present invention configured as described above, the magnetic path 44 by the control coil 27 connects the winding portion 28B of the second core 21B, the second
The winding part 28A of the core 21A, the fourth core 23,
The upper flange 33 of the first core 20 mainly extends into the third core 22 . On the other hand, two tuning coils 29A,
The magnetic path 46 of 29B can mainly extend within the winding portion 28B of the second core 21B, the winding portion 28A of the second core 21A, and the fourth core 23, as shown by dotted lines. The magnetic path 44 and the magnetic path 46 are
Winding portion 28A of second core 21A, second core 2
By changing the magnetic flux density by the control coil 27, the most overlap occurs in the winding part 28B of 1B.
By controlling the effective magnetic permeability of the second core 21A and the second core 21B, the inductance and Q of the tuning coils 29A and 29B can be adjusted simultaneously. Therefore, when the tuned coils 29A and 29B constitute a transformer, the characteristics of the transformer can be adjusted. Note that the fourth core 23 has a tuning coil 29A,
By extending the magnetic path 46 of 29B into the high frequency core, it has the role of reducing high frequency loss and maintaining the inductance and Q values, as well as their variable ranges, in a large state up to high frequencies. However, if it is a low frequency of 2MHz or less, it may be excluded. At this time, the magnetic paths 46 of the tuned coils 29A, 29B extend to the winding portion 24 of the first core 20, but the high frequency loss is negligible. If the fourth core 23 is made of metal, its dimensional accuracy can be improved. The second core has a tsuba in the middle, that is, the first
A core having a shape in which the second cores 21A and 21B shown in the figure are combined into one core may also be used.

FIG. 3 is an explanatory diagram of a longitudinal section showing another embodiment of the current controlled variable inductor of the present invention.

In FIG. 3, 50 is a first core, 51 is a second core, and 52 is a third core, and a control coil 53 is wound around the first core 50. The winding portion 56 of the second core 51 without an upper flange includes three tuning coils 54A, 54 that have been wound and formed in advance.
B, 54C is inserted. A second core 51 is inserted into the hollow portion 55 of the first core 50. Magnetic path 57 of control coil 53 and tuning coil 5
The magnetic paths 58 of 4A, 54B, and 54C overlap most in the winding portion 56, and by changing the magnetic flux density by the control coil 53, the effective magnetic permeability of the second core 51 is controlled and the tuned coils 54A, 54B, 5
The 4C inductance and Q value can be adjusted at the same time. A plurality of tuning coils may be wound in advance and fitted onto a single second core as shown in FIG. 3, or may be wound directly.

〔effect〕

As described above, the current-controlled variable inductor of the present invention has a plurality of tuned coils disposed within the hollow portion of the first core, and the inductance and Q value thereof can be adjusted simultaneously. Therefore, it is suitable for use when a transformer or the like is constructed by combining a plurality of tuning coils.

[Brief explanation of the drawing]

Fig. 1 is an explanatory longitudinal cross-sectional view showing an embodiment of the current controlled variable inductor of the present invention, Fig. 2 is an exploded perspective view, and Fig. 3 is an explanatory longitudinal cross-sectional view showing another embodiment.
FIG. 4 is an explanatory diagram of a conventional current controlled variable inductor. 20, 50...first core, 21A, 21B,
51... Second core, 22, 52... Third core, 23... Fourth core, 24, 28A, 28
B, 56... Winding part, 25, 55... Hollow part, 2
7, 53...Control coil, 29A, 29B, 54
A, 54B, 54C... Tuning coil, 44, 46
...magnetic path.

Claims (1)

[Scope of utility model registration request] A hollow part is provided in the winding part of the first core around which the control coil is wound, and a plurality of tuning coils are wound around one or more second cores in the hollow part.
The winding part of the core is inserted so that the winding part of the first core is parallel to the winding part of the first core, and the winding part of the first core is perpendicular to the bottom surface of the pot-shaped third core. A current controlled variable inductor characterized in that the magnetic paths of the control coil and the tuning coil overlap at the winding portion of the second core.