JPH0331062Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to a variable inductor.

[Prior Art] Conventionally, in this type of variable inductor, the inductance is adjusted to an arbitrary value by varying the number of turns of a winding wire wound around a drum-shaped bobbin, as shown in FIG. There is something. In addition, as another variable inductor, as shown in FIG. 6, by moving the screw-type magnetic core 12 up and down with respect to the fixed cup-shaped magnetic core 11, the distance between the screw-type magnetic core 12 and the winding part 13 can be changed. , there are those that can vary the inductance.

[Problems to be solved by the invention] However, in the variable inductor shown in FIG. 5, the number of turns of the winding must be varied according to the required inductance, which is inefficient.
Another drawback is that the inductance value varies from product to product.

Furthermore, in the variable inductor shown in FIG.
Since the structure is a semi-closed magnetic path, the effective magnetic permeability μ is low and a large inductance cannot be obtained. Further, since thread grooves must be formed on the hard magnetic cores 11 and 12 themselves, the manufacturing cost is high and the strength is low.

An object of the present invention is to provide a variable inductor that has a structure close to a closed magnetic circuit and can easily adjust a large inductance with high accuracy.

Another object of the present invention is to provide a variable inductor that is inexpensive to manufacture and has high strength.

[Means for Solving the Problems] A variable inductor according to the present invention includes a first core consisting of a disc-shaped core and a ring-shaped core standing upright from the outer periphery of the disc-shaped core, and a a second bobbin inserted into the bobbin, fixed to the disk-shaped core, having a through hole along the center line and around which a winding wire is wound; and a second bobbin inserted into the through hole of the bobbin and having a flange portion
a split plastic male screw that is placed over the flange of the second core, and a split plastic male screw that is screwed onto the male screw and fixed to the outer peripheral end of the ring-shaped core of the first core. It has a plastic female thread.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIGS. 1 to 3, the variable inductor according to an embodiment of the present invention has an upper cap 1,
It has a split rotating base 2, an upper ferrite core 3, a bobbin 4, and a lower ferrite core 5.

As will be described later, the lower ferrite core 5, the upper ferrite core 3, the split rotating base 2, and the upper cap 1 function as a first core, a second core, a male thread, and a female thread, respectively.

The upper ferrite core (second core) 3 is the flange part 3
a, and a split-type rotating base (male thread) 2 made of male threaded plastic is placed over this collar portion 3a. The split rotary base 2 is screwed into a female threaded portion 1a of an upper cap (female threaded) 1 made of plastic stick. The lower ferrite core (first core) 5 is formed by integrally molding a disk-shaped core 5a and a ring-shaped core 5b standing upright from the outer periphery of the disk-shaped core 5a. A bobbin 4 provided with a winding 4a is inserted into the lower ferrite core 5, and is bonded and fixed to the core bottom surface (disc-shaped core) 5a of the lower ferrite core 5. The bobbin 4 has a through hole along the center line, and the upper cap 1 and the lower ferrite core 5 are combined so that the upper ferrite core 3 is inserted into this through hole. It is adhered and fixed to the outer peripheral end of the ring-shaped core 5b.

In such a structure, the split type rotating base 2
By rotating , the gap between the upper ferrite core 3 and the lower ferrite core 5 is changed, and at the same time, the distance between the upper ferrite core 3 and the winding portion 4a of the bobbin 4 is also changed. As a result,
As shown in FIG. 4, it becomes possible to vary the inductance L.

Further, as shown in the figure, the variable inductor of the present invention has a structure close to a closed magnetic circuit, so that the effective magnetic permeability μ is high and a large inductance can be obtained.

Further, in the present invention, the rotating base 2 is of a split type. The reason for this is that when a split type rotary base 2 is used, it is necessary to bond the rotary base and the flange 3a of the upper ferrite core 3. Therefore, by making the rotating base 2 of a split type, it is possible to omit the bonding process.

Furthermore, in the collar part 3a of the upper ferrite core 3,
Compared to a structure in which a thread groove is directly formed, a structure in which a split rotating base 2 made of plastic is covered with a flange 3a of an upper ferrite core 3, as in the present invention, is cheaper to manufacture; Strength increases. This is because the ferrite core is hard, so it is difficult to form a thread groove in the flange 3a.
The split-type rotating base 2 made of plastic can be easily manufactured by injection molding, etc., and while the split-type rotating base 2 made of plastic is highly elastic, the upper ferrite core 3 itself is not elastic. This is because they are scarce.

[Effects of the invention] As is clear from the above explanation, according to the invention,
Since it has a structure similar to a closed magnetic circuit, a large required inductance can be easily and accurately adjusted, making it possible to provide a highly practical variable inductor. It also has the advantages of low manufacturing cost and high strength.

[Brief explanation of the drawing]

1 is a sectional view showing the configuration of a variable inductor according to an embodiment of the present invention, FIG. 2 is a perspective view of the variable inductor of FIG. 1, and FIG. 3 is an exploded perspective view of the variable inductor of FIG. Figure 4 is a characteristic diagram showing the relationship between the gap Gap and the amount of inductance change ΔL/L of the variable inductor in Figure 1, Figure 5 is a sectional view showing the structure of a conventional drum-shaped inductor, and Figure 6 is a diagram of the conventional variable inductor. FIG. 1...Plastic upper cap (female thread), 1a...Female thread portion, 2...Male threaded plastic split type rotating base (male thread), 3...
...Upper ferrite core (second core), 3a...
Flange part, 4... Bobbin, 4a... Winding part, 5... Lower ferrite core (first core), 5a... Disk-shaped core, 5b... Ring-shaped core 5b.

Claims (1)

[Claims for Utility Model Registration] A first core 5 consisting of a disc-shaped core 5a and a ring-shaped core 5b standing upright from the outer periphery of the disc-shaped core 5a, inserted into the first core 5, fixed to the disk-shaped core 5a and having a through hole along the center line;
The bobbin 4 on which the winding wire 4a is wound is inserted into the through hole of the bobbin 4, and the flange 3a is inserted into the through hole of the bobbin 4.
a split-type plastic male screw 2 that is fitted over the flange 3a of the second core 3; A variable inductor having a plastic female screw 1 fixed to the outer peripheral end of a ring-shaped core 5b.