JPS6334618B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a trimmer capacitor used in a tuning circuit, an oscillation circuit, etc., and used to adjust the tuning circuit, oscillation circuit, etc. to a predetermined frequency.

Structure of the conventional example and its problems FIGS. 1 and 2 show a conventional trimmer capacitor. In FIG. 1, 1 is a cylindrical body made of an insulator such as porcelain, and grooves 2 and 3 are formed on the sides of this body 1, and a tapped hole 4 is formed in the center. It is formed. 5
is a fixed electrode made of a conductor, for example, a tin plated iron plate, and this fixed electrode 5 is composed of a disk with a hole 6 in the center and a terminal 23 bent vertically from a part of this disk. has been done. 9
is a circular dielectric made of mica, for example, and has a hole 10 in the center. Reference numeral 11 denotes a movable electrode made of a dielectric material, for example, a tin plated iron plate, and the movable electrode 11 is composed of an electrode portion 12 and a terminal portion 21. A hole 14 is formed in the center of the electrode section 12 . Moreover, the shape of the terminal part 21 is such that it extends upward from a part of the electrode part 12 and is further bent downward into a U-shape. Reference numeral 15 denotes a washer made of a conductive material, for example, a tin plated iron plate, and a hole 16 is formed in the center. 17 is a screw that is sufficiently longer than the main body 1.

In FIG. 1, a main body 1 and a fixed electrode 5 are tightly fixed to each other. That is, a part 18 of the periphery of the main body 1 and a part 19 of the terminal 23 of the fixed electrode 5
are welded together. In addition, the fixed electrode 5
The projecting piece 7 is inserted into the groove 2 of the main body 1 and secured by caulking. Similarly, the groove 3 and the protruding piece 8 are also caulked. A portion 22 of the periphery of the main body 1 and a portion 31 of the terminal portion 21 of the movable electrode 11 are welded to each other. The tip 20 of the screw 17 is the washer 15
, the hole 16 of the movable electrode 11 , the hole 10 of the dielectric 9 , the hole 6 of the fixed electrode 5 , and the hole 4 of the main body 1 .
Screw it into the tap cut in.

FIG. 2 shows the completed state of the conventional trimmer capacitor.

Next, the operation of the above conventional trimmer capacitor will be explained. The trimmer capacitor has fixed electrode 5
There is a capacitance between the terminal 23 of the movable electrode 11 and the terminal 21 of the movable electrode 11. When screw 17 is rotated,
The electrode portion 12 of the movable electrode 11 approaches or moves away from the fixed electrode 5, the distance from the fixed electrode 5 changes, and the capacitance value changes.

However, in the above conventional example, the screw 1
Since the rate of change in capacitance with respect to the rotation angle of 7 is large, it is difficult to smoothly adjust the tuning frequency or oscillation frequency to a desired value using a tuning circuit or an oscillation circuit. Furthermore, if vibration occurs after adjusting the desired tuning frequency or oscillation frequency, there is a problem that the adjusted frequency may deviate significantly.

FIG. 3 is a graph showing how the capacitance between the terminal 23 of the fixed electrode 5 and the terminal 21 of the movable electrode 11 changes when the screw 17 is rotated in the conventional example shown in FIGS. 1 and 2. This is what I did. The horizontal axis in Figure 3 is the rotation angle of screw 17, and the left side is the rotation angle of screw 17.
7 is the direction to tighten, and the right side is the direction to loosen the screw 17. The vertical axis is the capacitance value, with the upper side being the direction of larger capacitance value and the lower side being the direction of smaller capacitance value. The adjustment point for the trimmer capacitor is often adjusted near point a, approximately in the center of the graph. In this case, when the screw 17 changes by a minute rotation angle Δθ ₁ , the capacitance changes by ΔC ₁ . Third
In the case of the figure, the slope near point a is large, so the rate of change in ΔC ₁ is large. Therefore, it is difficult to smoothly adjust the desired tuning frequency or oscillation frequency in a tuning circuit, oscillation circuit, etc., and after adjustment,
There were drawbacks such as the adjustment frequency being significantly shifted when there was vibration.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned conventional problems, and aims to reduce the slope of the change in capacitance value versus rotation angle of a trimmer capacitor.

Structure of the Invention The present invention attempts to reduce the slope of the change in capacitance value versus rotation angle by changing the shape of the variable electrode of a trimmer capacitor.

DESCRIPTION OF EMBODIMENTS The configuration of an embodiment of the present invention will be described below with reference to the drawings. 4 and 5 show an embodiment of a trimmer capacitor according to the present invention. Fourth
In the figure, 24 is a cylindrical main body made of an insulator, such as porcelain. Grooves 25 and 26 are formed on the side surfaces of the main body 24, and a tapped hole 27 is formed in the center. 28
is a fixed electrode made of a conductor, for example, a tin plated iron plate, and this fixed electrode 28 has a hole 2 in the center.
It consists of a disc with a hole 9 in it, and a terminal 46 that is bent in the vertical direction from a part of this disc. Furthermore, protrusions 30 and 31 are integrally provided on the fixed electrode 28 and are bent downward. 3
2 is a circular dielectric made of mica, for example, and has a hole 33 in the center. Reference numeral 34 denotes a movable electrode made of a conductor, for example, a tin plated iron plate, and the movable electrode 34 is composed of an electrode portion 35 and a terminal portion 44 . The electrode part 35
A hole 37 is formed in the center. Moreover, the shape of the terminal part 34 is such that it extends on the same plane as a part of the electrode part 35, is bent into a U-shape in the middle, and then bent downward. 38 is a washer made of a conductive material, for example, a tin plated iron plate, and a hole 39 is formed in the center. 40 is a screw that is sufficiently longer than the main body 24.

In FIG. 4, the main body 24 and the fixed electrode 28 are
They are tightly fixed to each other. That is, main body 2
A portion 41 of the periphery of the fixed electrode 28 and a portion 42 of the terminal 46 of the fixed electrode 28 are welded to each other. Further, the protruding piece 30 of the fixed electrode 28 is inserted into the groove 25 of the main body 24 and fixed by caulking. Similarly, groove 26
The protruding piece 31 is also caulked. A portion 45 of the periphery of the main body 24 and a portion 36 of the terminal portion 44 of the movable electrode 34 are welded to each other. The tip 43 of the screw 40 connects to the hole 39 of the washer 38 and the movable electrode 3.
4 hole 37, dielectric 32 hole 33, fixed electrode 28
It passes through the hole 29 of the main body 24 and is screwed into the tap cut in the hole 27 of the main body 24.

FIG. 5 shows the completed state of the trimmer capacitor in the above embodiment.

Next, the operation of the trimmer capacitor of this embodiment will be explained. The trimmer capacitor has a fixed electrode 28
There is a capacitance between the terminal 46 of the movable electrode 34 and the terminal 44 of the movable electrode 34. When the screw 40 is rotated, the electrode part 35 of the movable electrode 34 moves and the fixed electrode 28
The distance between the capacitor and the capacitor changes, and the capacitance value changes. 6th
The figure shows a characteristic diagram of the rotation angle of the screw of the trimmer capacitor according to this embodiment versus the change in capacitance value. The capacitance value change ΔC ₂ with respect to the minute rotation angle Δθ ₂ near the adjustment point h is the capacitance value change ΔC ₁ with respect to Δθ ₁ of the conventional trimmer capacitor shown in Fig. 3.
It has become significantly smaller.

Next, the reason will be explained with reference to FIGS. 7 and 8. FIG. 7 shows the main parts of the conventional trimmer capacitor. In the conventional trimmer capacitor shown in Fig. 7, when screw 17 is rotated, b
The movable electrode 11 moves up and down within a range of d using the point as a fulcrum. On the other hand, as shown in FIG. 8, in the trimmer capacitor according to the embodiment of the present invention, when the screw 40 is rotated, the movable electrode 34 moves up and down within a range of g using e as a fulcrum. In FIG. 8, the distance f between the screw 40 and the fulcrum e is longer than the distance c between the screw 17 and the fulcrum b in FIG. is smaller than the movable range d. Therefore, as shown in FIG. 6, the change in capacitance due to the rotation of the screw 40 becomes a gentle straight line.

Effects of the Invention The present invention has the above configuration, and according to the present invention, the following effects can be obtained.

Since the fulcrum of the movable electrode is configured to be outside the periphery of the main body, the rotation angle vs. capacitance change characteristic of the trimmer capacitor becomes a gentle straight line, allowing smooth adjustment to the desired tuning frequency or oscillation frequency using the tuning circuit, oscillation circuit, etc. Can be done.

For the same reason, vibration can reduce tuning frequency deviations, oscillation frequency deviations, etc. due to capacitance changes.

Compared to a trimmer capacitor having a conventional shape, the structure allows the main body and the fixed electrode to be shared, so it can be manufactured at a lower cost.

[Brief explanation of the drawing]

Figure 1 is an exploded perspective view of a conventional trimmer capacitor, Figure 2 is a side view of a conventional trimmer capacitor,
FIG. 3 is a diagram showing the rotation angle versus capacitance value change characteristic of a conventional trimmer capacitor, FIG. 4 is an exploded perspective view of a trimmer capacitor in an embodiment of the present invention, and FIG. Side view, No. 6
The figure shows the rotation angle vs. capacitance change characteristic of the trimmer capacitor, Figure 7 is a sectional view of the main parts of the conventional trimmer capacitor, and Figure 8 shows the main parts of the trimmer capacitor in an embodiment of the present invention. FIG. 24...Body, 25, 26...Groove, 27...
...hole, 28...fixed electrode, 29...hole, 30,3
1... protrusion, 32... dielectric, 33... hole, 34
...Movable electrode, 35...Electrode part, 37...Hole, 3
8... Washer, 39... Hole, 40... Screw, 4
3...Tip of screw, 44...Terminal part, 46...Terminal part.

Claims (1)

[Claims] 1. A main body made of an insulator and having a hole into which a screw is screwed, a first terminal portion and a fixed electrode having a hole through which the screw passes through, and fixed to the main body, and an electrode facing the fixed electrode. , a movable electrode integrally formed with a bent part provided on the outside of the periphery of the main body and a second terminal part attached to the main body, and between the electrode part of the movable electrode and the fixed electrode. A screw passes through the arranged dielectric, a hole formed in the electrode part of the movable electrode, a hole formed in the dielectric, a hole formed in the fixed electrode, and is screwed into the hole in the main body. A trimmer capacitor characterized in that, by rotating the screw, the electrode portion of the movable electrode is moved toward and away from the fixed electrode using the bent portion of the terminal portion of the movable electrode as a fulcrum.