JPH041706Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a high frequency variable coil used in electronic equipment such as a radio, and particularly relates to a structure of a high frequency variable coil suitable for a thin shape.

[Conventional technology]

A conventional example will be explained with reference to FIG. In the figure, 1 is an insulating substrate, 2 is an external terminal implanted on the substrate 1 and to which the end of the electric wire described later is connected, 3 is a drum core glued to the substrate 1, and 4 is a winding part of the drum core 3. 5 is a cup-shaped core that covers the drum core 3 and has a male screw formed on the outside and a groove 5a for an adjustment driver; 6 is a cup-shaped core on the inside. A resin holder is formed with a female thread that engages with the male thread 5, and a metal case 7 holds the holder 6. By inserting a driver into the groove 5a of the cup-shaped core 5 and rotating it, the cup-shaped core 5 moves up and down, and the coil 4
The inductance of changes.

[Problem that the invention attempts to solve]

However, in the case of the high frequency variable coil having the above configuration, the high frequency variable coil does not become smaller (thinner) but becomes larger due to the thickness of the ceiling surface 5b in which the groove 5a of the cup-shaped core 5 is formed. There was a problem.

[Means for solving problems]

This invention was proposed in order to solve the above problems, and the coil variable core provided on the outside of the drum core is made into a cylindrical ring core, and a groove for an adjustment driver is provided on the upper end surface of this ring core. The present invention provides a high frequency variable coil having a configuration of:

[Effect]

The present invention aims to reduce the thickness of the high frequency variable coil.

〔Example〕

Next, embodiments of the present invention will be described. FIGS. 1A, B, C, and D show a first embodiment of a high-frequency variable coil according to the present invention. They are a plan view, a cross-sectional view, a perspective view with the ring core separated, and a cross-sectional view of essential parts showing the relationship between the drum core and the ring core, respectively. In the figure, 1
1 is an insulating substrate, 12 is implanted in the substrate 11,
External terminal 13 to which the end of the electric wire to be described later is connected
1 is a drum core glued and fixed to a substrate 11;
4 is a coil formed by winding an electric wire around the winding portion of the drum core 13; 15 is a coil surrounding the drum core 13;
A cylindrical ring core with a male screw formed on the outside and grooves 15a and 15b for an adjustment driver on the upper end, and 16 is a resin-made ring core with a female screw formed on the inside that engages with the male screw of the ring core 15. holder, 17
is a metal case that holds the holder 16.
A groove 15a formed at the upper end of the ring core 15,
By inserting a screwdriver with a forked tip into 15b and rotating it, the ring core 15 moves up and down, and the inductance of the coil 14 changes. In the figure D, the inside of the ring core 15 has a stepped shape, and the upper brim 13 of the drum core 13
The electric wire is connected to the external terminal 12 by placing it close to the drum core 13 (gap G ₁ ) to increase the magnetic flux density and increasing the inductance value of the coil 14, and away from the lower rib 13b of the drum core 13 (gap G ₂ ). There is a passageway. Further, since the upper part of the ring core 15 is thick, the space on the upper end surface is large, and the grooves 15a and 15b are easily formed.

In the above structure, the ring core 15 can eliminate the ceiling surface formed in the conventional cup-shaped core, and the height of the high frequency variable coil is correspondingly reduced, resulting in a thinner shape.

FIGS. 2A, B, C, D, and E show modified examples of the drum core and ring core in the high frequency variable coil according to the present invention. Portions corresponding to those in FIG. 1D are given the same reference numerals. In Figure A, the inner surface of the ring core 15 is made smooth without any steps, and the drum core 1
The upper flange 13a of No. 3 is longer than the lower flange 13b to form gaps G ₁ and G ₂ . In the figure B, the upper inner surface of the ring core 15 and the upper rib 13a of the drum core 13 are respectively inclined to form a gap _G1 . In the figure C, the inside of the ring core 15 is inclined to form a gap _G1 between the inside of the ring core 15 and the upper rib 13a of the drum core 13, and a gap G2 between the inside of the ring core 15 and the lower rib 13b of the drum core ₁₃ . There is. In the figure D, the lower flange 13b of the drum core 13 is sloped to form a gap _G2 with the inside of the ring core 15. In the figure E, a notch 13c is formed in the lower rib 13b of the drum core 13 to form a gap _G2 .

3A and 3B are a sectional view and a perspective view with the ring core separated, respectively, showing a second embodiment of the high frequency variable coil according to the present invention. In the figure, 21 is an insulating substrate, 22 is an external terminal that is implanted in the substrate 21 and to which the end of the electric wire described later is connected, 23 is a three-brim drum core that is fixed to the substrate 21 by adhesion, and 24 ，
25 is a coil formed by winding an electric wire around the winding part of the drum core 23; 26 is a cylinder that surrounds the drum core 23, has a male screw formed on the outside, and has grooves 26a and 26b for an adjustment driver formed in the upper end. 27 is a metal case having a female thread formed therein to engage with the male thread of the ring core 26; 28;
is a capacitor assembled on the substrate 21 and electrically connected to the external terminal 22. In this example, L,
This is applied to a C filter, and by inserting a screwdriver with a bifurcated tip into the grooves 26a and 26b formed at the upper end of the ring core and rotating it, the ring core moves up and down, and the coil 24,
The inductance of coil 25 and the mutual inductance of coils 24 and 25 are varied.

[Effect of idea]

As mentioned above, the high-frequency variable coil of the present invention has a drum core bonded to a substrate, an electric wire wound around the winding portion of the drum core to form a coil, and an end of the electric wire attached to an external wire fixed to the substrate. A high-frequency variable coil connected to a terminal and provided with a core outside the drum core that varies the coil, wherein the core is a cylindrical ring core, and a groove for an adjustment driver is provided on the upper end surface of the ring core. Due to this structure, the high frequency variable coil can be made into a groove shape with a small height dimension, and has advantages such as being able to perform variable adjustment similar to the conventional one.

[Brief explanation of the drawing]

1A to 1D show a first embodiment of a high-frequency variable coil according to the present invention, in which FIG. 1A is a plan view, FIG. 1B is a sectional view, and FIG. 1C is a perspective view with the ring core separated.
Figure D is a sectional view of the main parts of the ring core and drum core.
2A to 2E are cross-sectional views of main parts showing modified examples of the ring core and drum core in the high frequency variable coil according to the present invention, and FIGS. 3A and 3B show a second embodiment of the high frequency variable coil according to the present invention. , FIG. 4A is a cross-sectional view, FIG. B is a perspective view of the ring core separated, and FIG. 4 is a cross-sectional view of a conventional high-frequency variable coil. 1, 11, 21... board, 2, 12, 22...
External terminal, 3, 13, 23...Drum core, 4,
14, 24, 25... Coil, 5... Cup-shaped core, 15, 26... Ring core, 6, 16... Holder, 7, 17, 27... Case, 5a, 15
a, 15b, 26a, 26b... groove.

Claims (1)

[Scope of utility model registration request] A drum core is bonded to a substrate, an electric wire is wound around the winding portion of the drum core to form a coil, an end of the electric wire is connected to an external terminal fixed to the substrate, and the coil is attached to the outside of the drum core. A high-frequency variable coil comprising a core for varying the oscillation rate, wherein the core is a cylindrical ring core, and a groove for an adjustment driver is provided on the upper end surface of the ring core.