JPS638112Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a variable capacitor used in radio receivers and the like.

In shortwave or ultrasonic radio receivers, small-capacity variable capacitors are often used for fine tuning adjustment, antenna circuit correction, and the like.
By the way, in small devices such as in-vehicle radio receivers, because the panel space is small, there is a tendency for the operation axes of switches, variable resistors, etc. to be concentric and multi-axis to operate multiple functions. Therefore, such a variable capacitor may also be operated by one of the multiple concentric axes, and other functions may be operated by the remaining axes. especially,
Car stereos with a built-in short-wave radio receiver often use a system in which the outer shaft of two concentric shafts operates the variable capacitor, and the inner shaft operates the tuner.

In such a case, conventionally, a gear 5 is attached to the outer shaft 1 and a gear 4 is attached to the variable capacitor 3, as shown in FIG. A configuration was used in which it was driven by operating the . Further, as shown in FIG. 2, a mounting plate 7 is provided in place of the chassis, and a variable capacitor 3 is attached to this, and a configuration is adopted in which the variable capacitor 3 is driven by gears 4 and 5 as in FIG. 1st
2, numeral 2 is the inner shaft.

However, these configurations require combinations of gears when attaching parts, making assembly complicated and time-consuming, and requiring dimensional accuracy for the parts. Moreover, the external dimensions of the structure become large, which does not meet the recent demand for miniaturization of parts.

This invention eliminates these problems,
The aim is to provide a variable capacitor that is compatible with downsizing and multi-functionality of components.

In order to achieve this objective, the present invention attaches a movable electrode or an electrode mounting plate to which the movable electrode is fixed directly to a pipe-shaped shaft, and places the movable electrode opposite the fixed electrode through a dielectric. A variable capacitor is constructed by fitting another operating shaft into a pipe-shaped shaft.

Hereinafter, one embodiment of the present invention will be explained in Figures 3 to 5.
This will be explained with figures. The variable capacitor of the present invention is rotatably fitted to a bearing 11 with an appropriate frictional force via a stator 9 made of a semicircular arc-shaped fixed side electrode 8 made of a conductor printed on an insulating plate and a conductive spring 10. A pipe-shaped outer shaft 13 is attached to the tip of the movable electrode 12 and is driven by a substantially semicircular movable electrode 12.
, a ring-shaped dielectric 14 disposed between the electrodes 8 and 12, an inner shaft 15 rotatably fitted to the outer shaft 13, and an insulated tip of the inner shaft 15 at the center of the bottom surface. A cap-shaped cover 18 that is fitted through a washer 16 and an E-ring 17 and whose opening side is attached to the stator 9;
It is composed of. Here, as shown in the figure, a rotation stop protrusion 12a is provided on a part of the movable side electrode 12, and a rotation stop that comes into contact with the rotation stop protrusion 12a and restricts the rotation angle of the outer shaft 13 is provided on a part of the cover 18. A protrusion 18a is provided. Furthermore, the stator 9, the dielectric 14, and the movable electrode 12 are connected to the bearing 1.
The outer shaft 13 is attached between the collar portion 11a of the outer shaft 13 and the tip caulking portion of the outer shaft 13. The movable electrode 12 is connected to a chassis (not shown) on the set side through an outer shaft 13, a conduction spring 10, and a bearing 11.

By rotating the outer shaft 13, the opposing area of the movable electrode 12 and the fixed electrode 8 changes, and the capacitance via the dielectric 14 can be changed. At this time, it is natural that the movable electrode 12 rotates together with the rotation of the outer shaft 13, but the dielectric 14 may or may not rotate together. In addition, the inner shaft 15
is used to operate other functions such as a tuner, and since a load such as a tuner is connected to its tip, it does not usually rotate together even if the outer shaft 13 is operated.

In the above embodiment, a two-axis system is used as the simplest example, but even in the case of a three-shaft system, the variable capacitor can be driven by the outermost axis or the middle axis. Furthermore, the capacitance can be increased by using a plurality of movable side electrodes and fixed side electrodes.

FIG. 6 shows another embodiment of the present invention, in which the electrode mounting plate 19 to which the movable electrode 12' is fixed is attached to the outer shaft 13.
The movable side electrode 12' and the terminal 20 are connected by a contactor 21. In this case, air is used as the dielectric.

FIG. 7 shows still another embodiment of the present invention, in which an electrode mounting plate 2 to which a movable electrode 12' is fixed is shown.
2 has a structure that also serves as a dielectric. Further, in this embodiment, the positional relationship between the stator 9 and the cover 18 is reversed from that of the above two embodiments, and the cover 1
8 is located on the side of the flange 11a of the bearing 11. In Figure 7, 21' is the cover 18
This is a contact provided inside the bottom surface of the contactor, and its tip is in contact with the movable electrode 12'.

The present invention is constructed as described above, and one of the plurality of concentric shafts is pipe-shaped, and the movable side electrode or the electrode mounting plate to which the movable side electrode is fixed directly to this pipe-shaped shaft is attached. By installing and manipulating the pipe-shaped shaft, the opposing area between the movable electrode and the fixed electrode provided opposite it can be changed to change the capacitance.
The structure is simple, reducing assembly man-hours,
In addition, it is possible to achieve miniaturization of parts, and it is also possible to meet the demand for multifunctionality.

[Brief explanation of the drawing]

1 and 2 are respectively front views showing conventional variable capacitors, FIG. 3 is a sectional view showing an embodiment of the variable capacitor according to the present invention, and FIG. 4 is a top view of the same essential parts. Figure 5 is an exploded perspective view.
FIGS. 6 and 7 are sectional views showing other embodiments of the variable capacitor of the present invention. 8... Fixed side electrode, 12, 12'... Movable side electrode, 13... Pipe-shaped shaft (outer shaft), 15... Shaft (inner shaft), 19, 22... Electrode mounting plate.

Claims (1)

[Scope of utility model registration request] One of the plurality of concentric shafts is made into a pipe shape, and a movable side electrode or an electrode mounting plate to which a movable side electrode is fixed is attached directly to this pipe-like shaft, and the movable side electrode or an electrode mounting plate to which the movable side electrode is fixed is mounted opposite to the movable side electrode or the movable side electrode. A variable capacitor provided with a fixed side electrode, and configured so that the capacitance can be changed by operating the pipe-shaped shaft, and other functions can be operated by other shafts.