JPS614220A - Variable porcelain capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a small, high-quality, dust-proof type variable ceramic capacitor that is used in various electronic devices.

Conventional structure and its problems A conventional variable magnetic capacitor has a structure as shown in FIGS. 1 and 2, for example.

That is, inside a case 2 formed by insert molding a stator terminal 1 having a contact portion 1a at its tip, a dielectric stator 4 shown in FIG. Metal rotors 5 are fitted in a non-rotatable manner and provided with rotor electrode portions, and are rotatably fitted and stacked, a spring θ having a rotor terminal is stacked in the upper opening, and the upper end of the case 2 is heated, etc. The metal rotor 5 is bent and fixed, and the spring 6 is irremovably fitted, and the facing area between the metal rotor 5 and the stator electrode 3 is changed, and the capacitance can be varied. Ta.

As described above, in the conventional variable ceramic capacitor, silver electrodes must be formed on the lower surface of the ceramic dielectric as the dielectric stator 4, but there are problems in mass production as described below.

In the stator electrode 3, (1) silver is used as the electrode material, and since it is formed by screen printing, it is necessary to align it on a printing jig board and bake the silver, making it impossible to print in large quantities at the same time.

Therefore, material costs and processing costs are high.

(2) Since the electrodes are formed by screen printing, misalignment of the electrode printing with respect to the ceramic dielectric material occurs. This is because the outer diameter of the porcelain dielectric material varies widely, and the clearance between the alignment stopper and the printing jig plate must be increased during printing, and the larger the number of simultaneous prints, the larger the misalignment. .

-Object of the invention The present invention solves these conventional drawbacks,
The object of the present invention is to provide an inexpensive variable ceramic capacitor that can be mass-produced and has no misalignment of electrodes with respect to a ceramic dielectric.

Structure of the Invention In order to achieve the object, the variable magnetic capacitor of the present invention includes a dielectric stator in which a semicircular recessed step is provided on one side of a ceramic dielectric, and a stator electrode is provided by plating the recessed step. This is the configuration used. With this configuration, the dielectric stator can be manufactured easily and with high precision.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings of FIGS. 3 to 6.

In Figures 3 to 6, Ryo is a bottomed cylindrical case made of synthetic resin with an opening at the top, and its configuration is such that stator terminals 8 and rotor terminals 9 made of metal plates are spaced apart. A contact piece 10 is provided on the bottom surface of the cylindrical case 7 at the tip of the stator terminal 8 by cutting and bending. The distal end of the rotor terminal 9 has a partially cut-out ring shape, and its peripheral edge is provided with engaging claws 11, 12, and 13 that protrude upward along the peripheral wall of the case 7.

Next, the spring 14 is made of a metal material, and each leg portion 15, 16, 17 is curved downward to have appropriate pressure contact.

Next, the metal rotor 18 is made of a metal material, and the lower surface has
A semicircular rotor electrode 1-9 and a cylindrical dummy electrode 2o
is formed to protrude downward. An adjustment groove 21 is provided on the upper surface.

Next, the dielectric stator 22 is provided with a semicircular recessed step 23 on the lower surface of the porcelain dielectric 22&, as shown in FIGS.
The stator electrode 24 is provided on the active paste of the recessed step part 23 by baking at a temperature of ~600°C and then plating, and the recessed step part 23 has a depth of about 0.1 to 0.2 cm. After forming the stator electrode 24, the stator electrode 24 is removed by polishing to a depth of about 0.05 mm that cannot be removed to reduce the level difference. FIG. 6 shows the manufacturing process of the dielectric stator 22.

That is, porcelain dielectric powder is press-molded to have a semicircular concave stepped portion 23 on the lower surface, and this is fired to obtain a porcelain dielectric 22a, and the concave stepped portion 23 of this ceramic dielectric 22a is formed by pressing.
Activated paste is applied to the stator electrode 24, baked at 400°C = 600°C, and plated to form the stator electrode 24 in the concave stepped portion 23.
After forming the stator electrode 24, the dielectric stator 22 is manufactured by polishing the lower surface of the ceramic dielectric 22a to such an extent that the stator electrode 24 is not scraped. The above-mentioned active paste has little bleeding or spreading, allows partial plating only to the application area, and has the effect of improving the adhesion strength of plating.

Next, to explain these assembly configurations, the dielectric stator 22 is sequentially moved from the upper opening of the case 7 to a position where the contact piece 1o provided on the bottom surface of the case 7 can come into contact with the stator electrode 24 of the dielectric stator 22. The metal rotor 18 is rotatably fitted and stacked thereon, and the spring 14 is further stacked, and the engaging claws 11, 12, and 13 protruding from the upper surface of the case 7 are respectively inwardly fitted. It is bent to sandwich the dielectric stator 22, metal rotor 18, and spring 14 with a constant pressure. Thereafter, a cap 25 made of synthetic resin is placed on the upper surface of the case 7, a cover 26 made of an insulator is placed on the lower surface of the case 9, and the case 7 is joined to the case 7 by press-fitting or the like.

With this configuration, the metal rotor 18 is rotated to change the opposing area of the rotor electrode 19 and the stator electrode 240, thereby adjusting the capacitance.

Effects of the Invention As described above, in the present invention, a dielectric stator is provided with a semicircular recessed step, and a stator electrode is formed in this recessed step by plating. There is no problem of misalignment of the electrodes with respect to the body, and since the electrodes are formed by plating, mass production is possible and costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of a conventional variable magnetic capacitor, Fig. 2 a and b are a plan view and a sectional view of a dielectric stator of the same capacitor, and Fig. 3 is an embodiment of the variable magnetic capacitor of the present invention. A sectional view, FIG. 4 is an exploded perspective view of the capacitor,
FIGS. 5a and 5b are a sectional view and a bottom view of the dielectric stator of the same capacitor, and FIG. 6 is an explanatory view showing the manufacturing process of the dielectric stator. 7... Case, 8... Stator terminal,
9...Parota terminal, 10...Contact piece, 14...
...Spring, 1 day...--Metal rotor,
19...Rotor electrode, 20...Rotor dummy electrode, 22...Dielectric stator 1.23...
... Dielectric stator recessed step portion, 24 ... Stator electrode, 25 ... Cap, 26 ... Cover. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure (Q) (1,)Figure 3Figure 4

Claims (1)

[Claims] Equipped with a case made of an insulator with stator terminals and rotor terminals insert-molded at the bottom and formed into a bottomed cylindrical shape.
Inside this case, a dielectric stator with integrated stator electrodes plated in a semicircular recessed step on the lower surface of the ceramic dielectric is fitted in a non-rotatable manner, and stator terminals are cut into the bottom surface of the cylindrical case. A contact piece is provided by raising the stator electrode, and the contact piece and the stator electrode are electrically connected.
A metal rotor is fitted in a rotatable manner, and a spring having a spring property at the contact part and press-contacting the metal rotor and the dielectric stator is incorporated into the upper opening, and the rotor terminal is inserted into the case through the outer circumferential wall of the case. A plurality of engaging claws protruding from the upper end are bent inward to irremovably lock the spring,
Combine a cap with a center hole on the top of the case,
A variable ceramic capacitor with a cover attached to the bottom of the case.