JPH0717142Y2 - Air variable condenser destruction prevention device - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a device for preventing destruction of an air variable capacitor used for an RF oscillator and the like. The invention relates to a destruction prevention device.

[Prior Art] An RF oscillator used in a UHF band RF modulator or the like has a circuit incorporated in a shield case, and an air variable capacitor is arranged in the circuit. Shown in FIGS. 3 to 6 is a conventional air variable capacitor, in which a stator electrode plate (2) (2) ... And a rotor electrode plate (3) (3) ... are alternately laminated inside a shield case (1). And combined in a polymerized state. And the rotor electrode plate (3) (3)
A groove (5) is bored in the upper end of the rotating shaft (4) to which is fixed, and the tip of the adjusting driver is inserted into the groove (5) to rotate the rotating shaft (4). The oscillation frequency was adjusted by changing the capacitance value of the air variable capacitor. In that case, the stator electrode plate (2) is
(2) ... and the rotor electrode plates (3), (3) ... may be destroyed. Therefore, as shown in FIG. 3 and FIG. 4, a resin holder (7) is fitted to the upper surface cover (6) of the shield case (1) and inserted into the hole (8) of the holder (7). The tip of the adjusting screwdriver was inserted for adjustment. Further, as shown in FIGS. 5 and 6, the opening (9) of the metallic upper cover (6) is subjected to a drawing process, a cut-and-raising process, or the like to form the rotary shaft (4). A configuration in which the periphery of the upper end portion is covered is also proposed.

[Problems to be solved by the invention] The conventional air variable capacitor described above is provided with a resin holder (7) to prevent damage due to incorrect insertion of the adjustment driver.
Was formed as a separate member and attached. Alternatively, the opening portion (9) of the metal top cover (6) is subjected to drawing processing or the like to prevent erroneous insertion of the adjusting driver. Therefore, many parts were used, and the number of assembly steps was large.

Therefore, there arises a technical problem that should be solved in order to prevent the adjustment driver from being erroneously inserted into each electrode plate portion and to simplify the component structure and obtain the destruction prevention device at a low cost. The present invention aims to solve this problem.

[Means for Solving the Problem] The present invention has been proposed in order to achieve the above-mentioned object, and is an air variable capacitor used for an RF oscillator, the upper end of a rotating shaft of a rotor electrode plate of the air variable capacitor. The upper part of the rotary shaft is provided with a disc-shaped stopper having a diameter larger than the shaft diameter of the rotary shaft, and the stopper is provided above the stopper. And a protrusion having a diameter smaller than that of the stopper, which is concentric with
The invention provides a device for preventing destruction of an air variable capacitor, which is characterized in that a groove is formed in the center of the protrusion.

[Operation] In this invention, a disk-shaped stopper having a diameter larger than the shaft diameter of the rotating shaft is provided at the upper end of the rotating shaft of the rotor electrode plate of the air variable capacitor, and the disk-shaped stopper is provided in the shield case. It is projected upwards. Furthermore, since a protrusion having a diameter smaller than that of the stopper and having a concentric circle with the stopper is provided at the center of the stopper, and a groove is provided at the center of the protrusion. An adjusting screwdriver is inserted into the groove and the rotary shaft is rotated to change the capacitance value of the air variable capacitor. At this time, even if the tip of the driver is deviated from the groove, the protrusion is provided in the center of the stopper concentrically with the stopper, so that the rotational force can be smoothly transmitted to the rotating shaft. At the same time, even if the driver comes off the groove, the stopper prevents the tip of the driver from entering the inside of the shield case.

[Embodiment] An embodiment of the present invention will be described below in detail with reference to FIGS. 1 and 2 of the attached drawings. For convenience of explanation, the same reference numerals are used for the same components as those of the conventional type. In the figure, reference numeral (1) is a metal shield case, and inside the shield case (1) are stator electrode plates (2) (2) ... And rotor electrode plates (3) (3). Are alternately laminated and combined in a polymerized state. And the rotor electrode plate (3)
The rotating shafts (4) to which (3) are fixed are inserted into the notches (10) and (10) provided on the upper and lower surfaces of the shield case (1), and the spring members (11) and (11) are inserted. The upper and lower side surfaces of the rotating shaft (4) are locked.

Here, a disc-shaped expanded portion is provided at the upper end of the rotating shaft (4) to form a stopper (12). The stopper (12) covers the upper portions of the rotor electrode plates (3) (3) ... Fixed to the rotary shaft (4) and the stator electrode plates (2) (2) ... In addition, a circular projection (13) concentric with the stopper (12) is provided on the upper surface of the center of the stopper (12), and a groove (5) for rotation is provided to the projection (13). ) Has been drilled. The groove (5) may be formed slightly deeper than the surface of the stopper (12), and the stopper (12) may be integrally formed with the rotary shaft (4) by the same member.

In the present device thus formed, the tip of the adjusting screwdriver is inserted into the groove (5) and the rotary shaft (4) is rotated to the left or right to change the capacitance of the air variable capacitor. Then, for example, the RF oscillation frequency of the RF modulator or the like is adjusted. At this time, if the groove (5) provided in the protrusion (13) is formed slightly deeper than the surface of the stopper (12), the step (5a) (5a) (5a) is formed at both ends of the groove (5). ) Is formed to prevent the adjustment driver from slipping. Further, the electrode plates (2) (2) ...
(3) Since the upper part of (3) ... Is covered, it is possible to prevent the adjusting driver from being mistakenly inserted into the inside of the air variable condenser, and the air variable condenser is not destroyed.

It should be noted that this invention can be modified in various ways without departing from the spirit of this invention, and it goes without saying that this invention extends to the modified version.

[Effect of the Invention] As described in detail in the above one embodiment, this invention is provided with a disk-shaped stopper having a diameter larger than the shaft diameter of the rotating shaft at the upper end of the rotating shaft of the rotor electrode plate of the air variable capacitor. The disk-shaped stopper is projected above the shield case. Furthermore, since a protrusion having a diameter smaller than that of the stopper and having a concentric circle with the stopper is provided at the center of the stopper, and a groove is provided at the center of the protrusion. An adjusting screwdriver is inserted into the groove and the rotary shaft is rotated to change the capacitance value of the air variable capacitor. At this time, even if the tip of the driver is deviated from the groove, the protrusion is provided in the center of the stopper concentrically with the stopper, so that the rotational force can be smoothly transmitted to the rotating shaft. At the same time, even if the driver comes off the groove, the stopper prevents the tip of the driver from entering the inside of the shield case. Thus, the tip of the driver does not destroy the stator electrode plate or the rotor electrode plate inside the shield case. Further, unlike the conventional case, since additional work such as attaching a holder or performing a drawing process is unnecessary, the number of parts can be reduced and the assembling work and the adjustment of the RF oscillation frequency can be smoothly performed. It is also possible to contribute to cost reduction.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention.
Fig. 1 is a plan view of the air variable condenser, and Fig. 2 is C- in Fig. 1.
It is a C line sectional view. FIGS. 3 to 6 show a conventional example. FIG. 3 is a plan view of an air variable condenser with a holder attached, FIG. 4 is a sectional view taken along the line AA of FIG. 3, and FIG. Plan view of the air variable condenser that has been drawn to the cover,
FIG. 6 is a sectional view taken along line BB in FIG. (3) …… Rotor electrode plate, (4) …… Rotating shaft (5) …… Groove, (12) …… Stopper

Claims (1)

[Scope of utility model registration request] 1. An air variable capacitor used in an RF oscillator, wherein an upper end portion of a rotary shaft of a rotor electrode plate of the air variable capacitor is projected above a shield case, and the upper end portion of the rotary shaft is provided with a rotary shaft. A disk-shaped stopper having a diameter larger than the shaft diameter of the moving shaft is provided, and a projection, which is concentric with the stopper and has a diameter smaller than the stopper, is further provided on the stopper.
A device for preventing breakage of an air variable capacitor, characterized in that a groove is formed in the center of the protrusion.