JPS6314852B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a rectangular high-voltage ceramic capacitor.

A conventional high-voltage capacitor has a disk shape, and is constructed as shown in FIG. 1, for example. That is, electrodes 2 and 3 are provided on both sides of a disc-shaped high voltage ceramic capacitor body 1, and lead terminals 6 and 7 are attached to the center portions of these electrodes 2 and 3 via connection terminals 4 and 5. , the outer peripheral surface of which is coated with resin 8. The resin coating of such a disc-shaped capacitor is made by inserting one lead terminal 7 into a through hole provided on the bottom of the molding die.
This is done by inserting the capacitor body 1 into a mold and injecting resin into the mold. In this case, since the lead terminal 7 is attached to the center part of the capacitor body 1,
Even if the capacitor element 1 rotates around the lead terminal 7 in the mold, the spatial distance between the outer surface of the capacitor element 1 and the inner wall of the mold does not change due to the disk shape, and the outer circumference The surface can always be coated with resin of uniform thickness. However, in recent years, a high-voltage variable resistor, which is constructed by housing a rectangular ceramic substrate with a film resistor on one side together with a slider etc. in an insulating case with an opening on one side, and a high-voltage ceramic capacitor have been integrated. There is a demand for a rectangular high-voltage ceramic capacitor that is suitable for being housed on the back side of the ceramic substrate inside the insulating case of a high-voltage variable resistor. However, if the capacitor body is made rectangular, no matter where the lead terminal is attached, there is no position that is equidistant from any point on the outer surface of the capacitor body. If resin molding is carried out in the same manner as in the case, as shown schematically in the plan view of FIG. When the capacitor body 9 is placed in a tilted position in the plane direction and the lead terminal 11 is installed at a position offset from the center in the longitudinal direction of the capacitor body 9, the third
As schematically shown in the vertical cross-sectional view of the figure, the capacitor body 9 is placed in an inclined position with respect to the inner bottom surface of the mold 10, and the resin coating is applied to the outer peripheral surface of the capacitor body with a uniform thickness. I can't do it anymore,
A problem arises in that various properties such as heat shock resistance and moisture resistance cannot be satisfied.

Further, as shown in FIG. 4, a full-surface electrode 12 is provided on the back side of the rectangular capacitor body 9, and split electrodes 13 and 14 are provided on the front side, and lead terminals 15 and 15 are provided on the split electrodes 13 and 14, respectively. 16, it is extremely difficult to coat the back side of the capacitor body 9 with resin.

The present invention has been made in view of these points, and it is possible to apply a resin coating of uniform thickness to the outer circumferential surface of a rectangular high-voltage ceramic capacitor body, thereby providing a high-voltage capacitor with excellent reliability. The object of the present invention is to provide a method for manufacturing a high-voltage ceramic capacitor that can realize a ceramic capacitor.

For this purpose, the present invention attaches a lead terminal and a spacer to an electrode surface formed on a high-voltage ceramic capacitor body, positions this spacer at a position approximately symmetrical with respect to the center point on the attached electrode surface, and By fitting the spacer into a recess shallower than the height of the spacer formed on the inner bottom surface of the mold, a predetermined space is formed between the spacer and the inner bottom surface of the mold to form a high voltage porcelain capacitor element. is placed in a mold for molding, and resin is injected into this mold.

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 5, 21 is a high-voltage ceramic capacitor body, and silver paste or the like is applied by screen printing on the opposing surfaces and baked, and electrodes 22, 23 are
form. The electrodes 22 and 23 can also be formed by other means such as plating or vapor deposition using appropriate electrode materials. Next, this electrode 2
Lead terminals 26 and 27 are connected to the 2nd and 23rd surfaces via connection terminals 24 and 25 using solder or the like. The connecting terminals 24 and 25 are connected to the lead terminals 26 and 25 in order to increase the adhesive strength with the electrode surfaces of the lead terminals 26 and 27.
The lead terminal 2 is formed to have a larger cross-sectional shape than the cross-sectional shape of the lead terminal 27.
It is connected to the tips of 6 and 27 by solder or the like. Note that it is also possible to form the lead terminals and the connection terminals as an integral part instead of forming them as independent parts as in this embodiment. Further, if the adhesive strength satisfies the required value even if the lead terminal is attached directly to the electrode surface, it is not necessarily necessary to use the connecting terminal. Next, a pair of spacers 28 and 29 made of an insulating material such as porcelain and taller than the connecting terminal 25 are adhered to the surface of the electrode 23 to which one lead terminal 27 is attached using an adhesive. Note that this pair of spacers 28, 2
9 are attached at positions spaced apart from each other and substantially symmetrical with respect to the center point on the surface of the electrode 23. Further, the spacers 28 and 29 may be attached to the electrode surfaces before the lead terminals 26 and 27 are attached. Further, the material of this spacer may be metal if it is used so that the electrode 23 is at ground potential, and in this case, it can be attached to the electrode surface with solder. High voltage ceramic capacitor body 2 with lead terminals and spacers attached like this
1 into a mold 30 for molding as shown in FIG.
Place it inside. In other words, this mold 30 has a through hole 31 formed at its bottom to draw out the lead terminal to the outside, and a recess with a depth shallower than the height of the spacers 28 and 29 at a position away from the through hole 31 on the inner bottom surface. 32 and 33 are formed. Therefore, the capacitor body 21 has its lead terminal 27 through the hole 3.
1 and pulled out to the outside of the mold, and by fitting the tips of the spacers 28 and 29 into the recesses 32 and 33, a predetermined space approximately parallel to the inner bottom surface of the mold is formed. It will be placed inside the mold. Note that the recess 32 on the inner bottom surface of the mold 30,
If the width of the capacitor element 33 on the side corresponding to the longitudinal direction of the capacitor body 21 is made larger than the width of the spacer, the accuracy of the mounting position of the lead terminal and the spacer can be made looser by that much. The mold 29 in which the capacitor body 21 is placed in this way
A resin 34 such as epoxy resin is injected into the inside and hardened. The appearance of the high-voltage ceramic capacitor thus obtained is shown in FIG. As is clear from this figure, the parts of the spacers 28 and 29 that were fitted into the recesses 32 and 33 on the inner bottom surface of the mold are exposed from the surface of the resin 34, but the recesses 32 and 33 on the inner bottom surface of the mold
If the depths of 2 and 33 are made as shallow as possible, they will not interfere with the use of the capacitor. In addition, by increasing the exposed portion of the spacer, it is also possible to actively utilize the exposed portion for positioning the capacitor when arranging the capacitor. The planar shape of the spacer is
In addition to the circle shown in the figure, any shape such as a square or a triangle may be used. Also, when the electrodes formed on the capacitor body have a structure as shown in Figure 4,
As shown in FIG.
8 and 39, resin coating can be applied in the same manner as in the case of the above-mentioned implementation row. In addition,
In the case of the electrode structure shown in FIG. 4, the divided electrodes 13, 1
If necessary, it is also possible to form a film resistor on the surface of the capacitor body over the four spaces to form a capacitor with an R.

The method for manufacturing a high voltage ceramic capacitor of the present invention includes:
Because it involves the processes described above, even if the capacitor body is rectangular, it is possible to apply a resin coating to the outer peripheral surface of the capacitor body with a uniform thickness, and it has excellent heat shock resistance and moisture resistance. It has the advantage that high-voltage ceramic capacitors with excellent reliability can be manufactured without deterioration of electrical characteristics such as.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view of the main part of a conventional disc-shaped high-voltage porcelain capacitor, and Figures 2 and 3 are disadvantages that occur when a rectangular high-voltage porcelain capacitor body is coated with resin using the conventional method. 4 is a side view illustrating the electrode structure of a rectangular high-voltage ceramic capacitor, and FIGS. 5, 6, and 8 are diagrams showing one embodiment of the present invention FIG. 7 is a side view and a vertical cross-sectional side view of a main part for explaining the manufacturing method of a high-voltage ceramic capacitor as an example, and FIG. 7 is an external perspective view of a high-voltage ceramic capacitor completed by the manufacturing method of the present invention. 21...High voltage porcelain capacitor element, 22,2
3... Electrode, 24, 25... Connection terminal, 26, 2
7... Lead terminal, 28, 29, 35, 36...
Spacer, 30, 37... Mold die, 31
...Through hole, 32, 33, 38, 39...Dent, 3
4...Resin.

Claims (1)

[Scope of Claims] 1. Manufacture of a high-voltage ceramic capacitor in which a lead terminal is attached to an electrode formed on a rectangular plate-shaped high-voltage ceramic capacitor body, and a resin coating is applied to the outer peripheral surface of the capacitor body. A method, comprising: (a) forming an electrode on a high-voltage ceramic capacitor body; (b) attaching a lead terminal to an electrode surface formed on the high-voltage ceramic capacitor body; (c) forming an electrode on a high-voltage ceramic capacitor body. A step of attaching two spacers to one electrode surface at positions spaced apart from each other and substantially point-symmetrical with respect to the center point on the electrode surface; d. High-voltage porcelain capacitors are formed by fitting the spacers into recesses shallower than the height of the spacers formed on the inner bottom surface of the mold to form a predetermined space between the spacers and the inner bottom surface of the mold. A process of placing the element in a molding die; e) Injecting resin into the molding die and applying a resin coating to the outer peripheral surface of the high voltage ceramic capacitor element. A method for manufacturing high voltage porcelain capacitors.