GB2167233A

GB2167233A - Variable rotary capacitors

Info

Publication number: GB2167233A
Application number: GB08522921A
Authority: GB
Inventors: Yasufumi Ito
Original assignee: Alps Electric Co Ltd
Current assignee: Alps Alpine Co Ltd
Priority date: 1984-11-20
Filing date: 1985-09-17
Publication date: 1986-05-21
Also published as: GB8522921D0; GB2167233B; KR900002521Y1; JPH041726Y2; JPS6190233U; KR860006692U

Abstract

A small size variable rotary capacitor has sets of Stator plates (1, 12) made of a thin metal sheet covered with a dielectric material (1A) and fixed to opposing poles (17a, 18a) projecting from the substrates (17, 18) to face the rotor plates but be spaced therefrom. Each projecting pole (17a, 18a) is of generally rectangular cross-section. An insulating member (19) having a shape which approximately mates with the two poles (17a, 18a), is sandwiched between the sets of stator plates (1, 12) and the poles (17a, 18a). The shape of the poles allows terminals (10, 10') for the sets of stator plates plates to be received through the poles. <IMAGE>

Description

SPECIFICATION Variable capacitors FIELD OF THE INVENTION The present invention relates to a small size variable capacitor and more particularly to a small size variable capacitor which is just suited to a small size radio receiver or radiocassette, etc.

BACKGROUND OF THE INVENTION Fig. 3 to Fig. 4 shows a small size variable capacitor of the prior art. In this prior art, 1, 1 are stator plates covered with the dielectric material 1A; 2, 2 are washers alternately provided with the stator plates 1. These are respectively arranged in plural numbers, forming a group of stator 3. The rotor plates 4, 4 are alternately arranged with the washers 5, 5 through the rotor shaft and are fixed pressurizingly. 7 is a rotor section corresponding to the stator group 3.

8 is a front substrate having the pole 8a which supports the stator group 3 and a bearing 8b through which the rotor shaft 6 is inserted. 9 is a rear substrate having a pole 9a corresponding to the pole 8a of the front substrate 8 and a hole 9b which supports the rotor shaft 6.

The rotor shaft 6 and stator group 3 are arranged in such a manner as being sandwiched by the front substrate 8 and rear substrate 9, and these are assembled by a metal terminal 10 which is pressurizingly provided through the pole 9a from the direction of the rear substrate 9, engages with the stator group 3 and is also pressurizingly inserted through the pole 8a of the front substrate 8.

In general, a small size variable capacitor has a structure that a plurality of poles are provided, each pole supports a stator group respectively and and the rotor shaft is also capable of fixing a plurality of rotor sections corresponding to the respective stator group.

However, in such a prior art, there is a limitation that only the sections as many as the number of poles cna be provided because one stator is fixed to one pole for effectiveness of assembling. Moreover, also arises the disadvantage that in case poles are increased without limitation, the shape of substrate is complicated, for example, as a hexagon or octagon, particularly working efficiency for adjusting static capacitance of variable capacitor is deteriorated or the standardization of 4-section (almost square shape) variable capacitance which is now most widely used and the terminal pitch is impossible.

In other words, the structure of such small size variable capacitor cannot meet the supply of a small size multi-section variable capacitor just suited to a radio receiver which assures reception of thre or more frequency bands such as the AM broadcasting, FM broadcasting, Short-wave broadcasting and TV broadcasting which have many listeners in these years.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a small size variable capacitor which improves disadvantages of the prior art and is particularly suited to a small size radio receiver and radio cassette.

The present invention attains said object by employing the structure of a small size variable capacitor where a rotor shaft is rotatably provided between a pair of substrates arranged face to face, a rotor plate made of the metal thin plate is fixed to this rotor shaft and a stator plate made of a metal thin plate which is covered with dielectric material is fixed to the pole provided to said substrate facing to the rotor plate with small clearance, hence characterized in that the poles of said pair of substrates are formed in such a form as being protruded from almost square external shape and an insulating member in the shape almost matching such pole is inserted into the two pair of said stator plate and is supported by the pole in such a shape as beng protruded from almost square external shape of said pair of substrates.

BRIEF DESCRIPTION OF THE DRA WINGS Fig. 1 is the vertical cross section of essential part of a small variable capacitor indicating an embodiment of the present invention. Fig.

2 is a perspective view of the dissembled essential part. Fig. 3 is the vertical cross section of essential part of small variable capacitor of the prior art. Fig. 4 is a perspective view of disassembled essential part of small variable capacitor of the prior art. Fig. 5 and Fig. 6 are perspective view of disassembled essential part of small variable capacitor of the present invention indicating a modification where a cut-away part or protrusion is provided to the insulating member and substrate.

DETAILED DESCRIPTION OF THE INVENTION The preferred embodiment of the present invention is explained hereunder with reference to Fig. 1, Fig. 2, Fig. 5 and Fig. 6. It is to be noted that like parts are designated by like reference numerals through the accompanying drawings.

In Fig. 1 and Fig. 2, 1,1 are first stator plates having the same structure as the prior art; 2, 2 are washers which are alternately provided with the stator plates 1,1. The first stator group 1 is formed by a plurality of them.

12, 12 are second stator plates covered with the dielectric material 1A; 13, 13 are washers which are alternately provided with the stator plates and the second stator group 14 is formed by a plurality of them. A support hole 1 2b of the second stator plate 12 is formed larger than the support hole 1b of the first stator plate 1, the washer 13 is formed almost rectangular having the support hole 13a and through hole 13b and the support hole 1 3a is formed larger than the support and through hole 2a of the washer 2. 19 is an insulating member to be inserted between the first stator group 11 and the second stator group 14, and it has a protrusion 19a which engages with the support hole 1 2b of said stator plate 12 and the support hole 13a of washer 13.The rotor plates 4, 4 are alternately provided with the washers 5, 5 and are provided through the rotor shaft and fixed thereto. 15, 16 are rotor sections corresponding to the stator groups 11, 14.

17 is the front substrate having the pole 1 7a which supports the stator groups 11, 14 and insulating member 19 and the bearing 1 7b through which the rotor shaft 6 is provided. 18 is the rear substrate having the pole 18a corresponding to the pole 17a of the front substrate and the hole 9b which supports the rotor shaft 6.

As shown in the figure, the rotor shaft 6, stator groups 11, 14 and insulating member 19 are arranged in such a manner as being sandwiched between the front substrate 17 and rear substrate 18. Namemly, these are provided through the pole 18a from the direction of the rear substrate 18 and a protrusion 19a of the insulating member 19 which engages with the second stator group 14 and then assmebled with the metal terminal 10 which engages with the first stator group 11 and is pressurizingly inserted into the pole 17a of the front substrate and the metal terminal 10' which engages with the second stator group 14 through the pole 18a and is pressurizingly inserted into the pole 1 7a of the front substrate 17.

Here, the pole 1 7a of front substrate 17 and the pole 18a of rear substrate are formed almost square shape and protruded as required as possible, while the insulating member 19 is formed in such a manner as almost matching these poles.

Fig. 5 and Fig. 6 respectively show the modifications of the present invention. In Fig. 5, a protrusion 19b is provided to the insulating member 19, a cut-away part 17c is provided to the front substrate, in Fig. 6 a cut-away part 1 9c is provided to the insulating member 19 oppositely and a protrusion 1 7d is provided to the front substrate 17.

As explained above, according to the present invention, a small size variable capacitor, where a rotor shaft is rotatably provided between a pair of substrates arranged face to face, a metal thin plate rotor plate is fixed to this rotor shaft and a stator plate made of metal thin plate covered with the dielectric material is fixed to the pole formed to the front substrate opposingly to the rotor plate with a small clearance, has the structure that the poles of said pair of substrates are formed in such a shape as being protruded from the external shape of almost square shape, the insulating member in such a shape as almost matching such poles in inserted to two pairs said stator plates and is supported by the pole in such a shape as being protruded from the external shape of almost square of said a pair of substrates.

Thereby, the shape of substrate of prior art described above is not complicated like the hexagon or octagon, accordingly working efficiency for adjusting static capacitance of a variable capacitor is not deteriorated and the terminal pitch can be standardized with reference to the 4-section variable capacitor. Moreover, since the structure of prior art is also considered wherein one section is provided correponding to one terminal, increase of cost can be minimized for constituting the multisection capacitor, and the insulating member can be fixed temporarily and positioned and workability can also be improved by providing a cut-away part or protrusion to the insulating member and substrate.

Claims

1. A variable capacitor where a rotor shaft is rotatably provided between a pair of substrates arranged face to face, a rotor plate made of the metal thin plate is fixed to this rotor shaft and a stator plate made of a metal thin plate which is covered with dielectric material is fixed to the pole provided to said substrate facing to the rotor plate with small clearance, hence characterized in that the poles of said pair of substrates are formed in such a form as being protruded from almost square external shape and an insulating member in the shape almost matching such pole is inserted into the two pair of said stator plate and is supported by the pole in such a shape as being protruded from almost square external shape of said pair of substrates.

2. A variable capacitor according to claim (1) where a cut-away part is provided to the opposing surfaces of poles of a pair of substrates, and a protrusion which engages with said cut-away part is provided to the insulating member in such a shape as almost matching said pole.

3. A variable capacitor according to claim (1) where a protrusion is provided to the opposing surfaces of poles of a pair of substrates and a cut-away part which engages with said protrusion is provided to the insulating member in such a shape as almost matching said pole.

4. A variable capacitor substantially as hereinbefore described, with reference to Figs 1, 2, 5 and 6 of the accompanying drawings.