JPH0346493Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a variable inductor constructed by combining a drum-shaped core and a cap-shaped core, and is widely used in electronic equipment such as telecommunications equipment and information processing equipment.

Structure of conventional example and its problems As shown in FIGS. 1 and 2, this type of conventional variable inductor consists of a drum-shaped core 1 around which a coil 2 is wound and a cap-shaped core 3 that is placed over the drum-shaped core 1. The drum-shaped core 1 is attached to the terminal board 4 in which the terminal 5 is embedded, and the male screw 6 provided on the outer periphery of the cap-shaped core 3 is screwed into the inside of the case 7 fixed to the terminal board 4, passing through the case 7. The inductance of the coil 2 can be changed by inserting a driver into the groove 9 through the hole 8 and rotating the cap type core 3 to move the cap type core 3 up and down. In this way, in conventional inductors, the cap-type core moves up and down, so in addition to the gap between the top surface of the drum-type core and the case for inserting the cap-type core, there is also a space for the cap-type core to move up and down. A gap is required, which makes it impossible to reduce the height of the case. Further, in order to convert the rotation of the cap-type core into vertical movement, it is necessary to provide thread grooves on the side surface of the cap-type core and the inner wall surface of the case, which increases the cost.

Purpose of the invention The purpose of this invention is to solve these conventional problems.The invention is a compact variable coil inductance that can change the inductance over a wide range by simply rotating the cap-type core without vertically moving it. An inductance device is provided.

Structure of the invention The present invention has a configuration in which both the drum-shaped core and the cap-shaped core are divided into a section made of a material with high magnetic permeability and a section made of a material with low magnetic permeability in a cross section perpendicular to the axis of rotation. By rotating the mold core, the inductance of the coil wound around the drum core can be changed.

DESCRIPTION OF THE EMBODIMENTS FIGS. 3 and 4 show an embodiment of the present invention, with FIG. 3 being a perspective view of the drum-shaped core 11 and cap-shaped core 12, and FIG. 4 being an assembled sectional view of the whole. The drum-shaped core 11 is vertically divided into two parts, one half 11
a is made of a material with high magnetic permeability, and the other half 11
b is made of a material with lower magnetic permeability than that,
Similarly, the vertical half 12a of the cap-shaped core 12 is made of a material with high magnetic permeability, and the other half 12b is made of a material with lower magnetic permeability. The coil 2 is wound around the drum-shaped core 11 and fixed to the terminal plate 4, and the cap-shaped core 12 is rotatably inserted inside the case 7, covered with the drum-shaped core 11, and fixed to the terminal plate 4 of the case 7. ing.

Now, when the driver is inserted into the groove 9 provided in the cap-shaped core 12 through the hole 8 provided in the upper part of the case 7 and the core 12 is rotated, the high magnetic permeability part 12a of the cap-shaped core and the magnetic permeability of the drum-shaped core are The coil 2 is completely overlapped with the high part 11a of the coil 2.
The inductance of the coil 2 becomes the maximum, and when the high permeability part 12a of the cap-shaped core and the high permeability part 11a of the drum-type core do not overlap at all, the inductance of the coil 2 becomes the minimum,
The maximum and minimum inductances are obtained at a position intermediate between . In this way, the inductance can be changed simply by rotating the cap-type core.

The volume ratio of the high magnetic permeability part and the low magnetic permeability part of the drum-shaped core and the cap-shaped core does not have to be 1:1 as shown in the embodiment shown in FIG. It is sufficient that both cores have a high permeability part and a low permeability part in the vertical cross section, and in Figures 5 and 6, the volume ratio of the high permeability part and the low permeability part is not 1:1. This is an unbalanced example, and FIG.
c is the maximum magnetic permeability, and the opposite outer peripheral end 11d,
This is another embodiment of the present invention in which the magnetic permeability gradually changes between 12d and the lowest magnetic permeability.

Effects of the invention As described above, the variable inductor of this invention can change the coil inductance by simply rotating the cap-type core without vertical movement, so the coil height can be changed compared to conventional ones. can be lowered. Further, since the screw grooves on the side surface of the cap type core and the side surface of the case, which were necessary in the conventional case, are not required, the cost can be reduced.

Furthermore, both the drum-type core and the cap-type core are structured so that they are divided into a material with high magnetic permeability and a material with low magnetic permeability in a cross section perpendicular to the rotation axis, so that By selecting the cylindrical magnetic permeability of the material or changing the volume ratio of parts with different magnetic permeability, it is possible to create a small inductor with an arbitrary variable range. In addition, since each core does not require special shapes and dimensions, it is easy to manufacture, and products with stable dimensional accuracy can be easily obtained, making it suitable for mass production. .

[Brief explanation of the drawing]

Figures 1 and 2 show an example of a conventional variable inductor, with Figure 1 being a perspective view of its drum-shaped core and cap-shaped core, Figure 2 being a cross-sectional view of the entire assembly, and Figures 3 and 4. shows an embodiment of the present invention, and FIG. 3 is a perspective view of its drum-shaped core and cap-shaped core;
FIG. 4 is an overall assembled sectional view, and FIGS. 5, 6, and 7 are perspective views of a drum-type core and a cap-type core, respectively, according to other embodiments of the present invention. 1, 11...drum-shaped core, 2...coil,
3, 12... Cap type core, 4... Terminal board, 5
...Terminal, 6...Screw groove, 7...Case.

Claims (1)

[Scope of utility model registration request] It has a drum-shaped core around which a coil is wound, and a cap-shaped core that is rotatably placed on the outside of the drum-shaped core, and both the drum-shaped core and the cap-shaped core are arranged perpendicularly to their rotational axis. A variable inductor configured so that its cross section is divided into a material with high magnetic permeability and a material with low magnetic permeability.