JPH0351961Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to a variable capacitor.

[Conventional technology and its problems]

Conventionally, variable capacitors used as electric circuit elements are disclosed in Japanese Utility Model Publication No. 7306/1983 and Japanese Utility Model Publication No. 54-7306.
As shown in Publication No. 7307, etc., the variable capacitor was a single component, and was connected to the wiring pattern of the circuit board by soldering or the like. For this reason, the installation work is troublesome, it is not suitable for automated assembly, and the number of parts increases, making it uneconomical.

In order to solve these problems,
In Publication No. 13895, a movable electrode is formed on the lower surface of an insulating disk, and this insulating disk is attached to the protruding end of a rotating shaft that fits into a through hole of a printed circuit board, so that the movable electrode and the fixed electrode of the printed circuit board are connected. The movable electrode and the fixed electrode are opposed to each other, and a dielectric material is interposed between the movable electrode and the fixed electrode. An operating section for rotating the insulating disk is provided at the end of the rotating shaft opposite to the insulating disk, and a biasing spring is interposed between the operating section and the bottom surface of the printed circuit board. This applies a biasing force to the movable electrode toward the fixed electrode, and also applies a slip torque to the rotating shaft.

In addition, in Japanese Utility Model Publication No. 57-4220, a fixed electrode is formed using a thin metal film on a ceramic substrate, and a screw is screwed into a screw hole provided in the ceramic substrate from the back side of the substrate, and the protruding end of the screw is A metal plate is fixed by soldering or the like to face the fixed electrode, and a biasing spring is provided between the screw head and the ceramic substrate.

However, both of the above-mentioned conventional technologies have a large number of parts, are complex in structure, and in particular are extremely complicated to attach the movable electrodes and metal plates, so they are not suitable for automatic assembly at all, and are not suitable for reducing manufacturing costs. There was a problem above.

In addition, in the former conventional example, the variable electrode formed on the lower surface of the insulating disk slides on the upper surface of the dielectric, so the movable electrode is prone to wear and peeling, resulting in a lack of reliability. There is. Also,
The latter method uses the air interposed between the metal plate and the fixed electrode as a dielectric, so it has poor dielectric efficiency and has the drawback of increasing the size of the device when trying to obtain a large capacitance. Furthermore, the metal plate is bent by impact, and the capacitance is likely to change, resulting in reliability problems.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a highly reliable variable capacitor that has an extremely simple structure, is extremely easy to attach to a circuit board, is suitable for automatic assembly, and is highly reliable.

[Means for solving problems]

The features of the present invention include a circuit board with an electrode pattern formed around a through hole, a rotating member rotatably provided on the top surface of the electrode pattern of the circuit board, and a rotating member vertically provided on the bottom surface of the rotating member. and a rotating shaft that fits into the through hole and rotatably attaches the rotating member to the circuit board, the rotating member is formed of a dielectric material, and the electrode pattern is provided on the upper surface of the rotating shaft. An engagement groove is formed in which the rotating electrode facing the holder and the tip of the jig can be engaged, the rotating shaft is formed integrally with the rotating body, and the tip of the rotating shaft has a A pair of elastic pieces are provided facing each other through a slot, and both elastic pieces engage with the lower edge of the through hole to rotatably and irremovably lock the rotating member to the circuit board. There is a tapered locking protrusion.

[Effect]

Since the rotating body is made of a dielectric material and the rotating electrode is provided on the upper surface, the number of parts is reduced and the rotating electrode does not wear out.

The rotating body and the rotating shaft are integrally formed, and an elastic engagement part is provided at the tip of the rotating shaft to engage with the edge of the through hole in the circuit board, which further reduces the number of parts and reduces the number of parts on the rotating body's circuit board. Installation becomes extremely easy.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

1 and 2, a circuit board 1 is made of an insulator such as epoxy resin or ceramic, and the upper surface of the circuit board 1 has wiring patterns 2a, 2b and electrode patterns 3a, 3.
b is formed. The electrode patterns 3a and 3b are formed around a through hole 4 formed in the circuit board 1, and are not electrically connected to each other. The rotating member 5 is made of a dielectric material such as ceramic, and has a rotating electrode 6 formed on its upper surface.
A rotating shaft 7 is integrally provided vertically on the lower surface. This rotating shaft 7 is rotatably fitted into the through hole 4 of the circuit board 1. Elastic pieces 72, 7 are provided at the tip of the rotating shaft 7.
2, and tapered locking protrusions 73, 73 that become thinner toward the tips are formed at the tips of both elastic pieces 72, 72, and the locking protrusions 7
3, 73 is formed with an inclined portion 73a that is inclined toward the shaft portion 74. The locking protrusion 73 engages with the lower edge of the through hole 4, whereby the rotating member 5 is rotatably and non-removably attached to the circuit board 1. The locking protrusion 73 engages with the lower edge of the through hole 4 at the inclined portion 73a, and this engagement force causes the rotating member 5 to come into elastic contact with the circuit board 1. Further, in order to facilitate rotational operation of the rotating member 5, an engagement groove 5a is provided on the upper surface of the rotating member 5, into which the tip of a screwdriver or the like can be engaged.

Assembly and mounting of this variable capacitor is completed by simply pushing the rotary shaft 7 into the through hole 4 from its tip. That is, when the rotary shaft 7 is pushed into the attachment hole 5a and the through hole 4 from the tip, the elastic pieces 72, 72 are bent inward by the tapered surfaces of the locking protrusions 73 and enter. By pushing further, the shaft portion 74 is press-fitted into the mounting hole 5a, and the locking protrusion 7
The inclined portion 73a of No. 3 engages with the lower edge of the through hole 4, whereby the rotating member 5 is rotatably and non-removably attached to the circuit board 1, completing the assembly and mounting of the variable capacitor.

When adjusting the capacitance of the variable capacitor, the tip of a screwdriver or the like is engaged with the engagement groove 5a of the rotating member 5, and the rotating member 5 is rotated. This results in
The facing area of the electrode patterns 3a, 3b and the rotating electrode 6 changes to adjust the capacitance.

〔effect〕

As explained in detail above, according to the present invention, the rotating member on which the rotating electrode is formed is mounted on the electrode pattern of the circuit board via the rotating shaft integrally vertically provided on the lower surface of the rotating member, and The tip of this rotating shaft is provided with elastic pieces facing each other via a slot, and tapered locking protrusions are provided on the tips of both elastic pieces, making assembly and mounting extremely easy. Automation can be easily achieved and manufacturing costs can be reduced. In addition, since the rotating body itself is made of dielectric material and the rotating electrodes are formed on the top surface of the rotating body, the number of parts is further reduced, and the rotating electrodes do not wear out, peel off, or bend due to impact, which increases reliability. will improve.

[Brief explanation of the drawing]

The drawings relate to one embodiment of the present invention, in which FIG. 1 is a sectional view thereof, and FIG. 2 is an exploded perspective view thereof. DESCRIPTION OF SYMBOLS 1... Circuit board, 3a, 3b... Electrode pattern, 4... Through hole, 5a... Engagement groove, 5... Rotating member, 6... Rotating electrode, 7... Rotating shaft, 71... Slot , 72... elastic piece, 73... locking protrusion.

Claims (1)

[Claims for Utility Model Registration] A circuit board having an electrode pattern formed around a through hole, a rotating member rotatably provided on the upper surface of the circuit board, and a rotating member vertically provided on the lower surface of the rotating member. and a rotating shaft that fits into the through hole and rotatably attaches the rotating member to the circuit board, and the rotating body is formed of a dielectric material, and has a is formed with a rotating electrode facing the electrode pattern and an engagement groove in which the tip of the jig can engage; the rotating shaft is formed integrally with the rotating body; A pair of elastic pieces facing each other via a slot are provided at the tip, and both elastic pieces engage with the lower edge of the through hole to freely rotate the rotating member onto the circuit board. A variable capacitor characterized in that the capacitor is provided with a tapered locking protrusion that locks the capacitor in an irremovable manner.