JPS6314851B2 - - 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 porcelain 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 disk-shaped capacitor is achieved by inserting one lead terminal 7 into a through hole provided at the bottom of a molding die, placing the capacitor body 1 in the mold, and then inserting the capacitor body 1 into the mold. This is done by injecting resin into the inside. In this case, since the lead terminal 7 is attached to the center of the capacitor body 1, even if the capacitor body 1 rotates around the lead terminal 7 in the mold, the outer surface of the capacitor body 1 The spatial distance from the inner wall of the mold does not change because of the disk shape, and the outer peripheral surface can always be coated with a uniform thickness of resin. 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. is being carried out,
A rectangular high-voltage ceramic capacitor is required that is suitable for being housed on the back side of a ceramic substrate in an 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.

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 peripheral surface of a rectangular high-voltage ceramic capacitor body in which lead terminals are attached to each of the electrodes on both sides. It is an object of the present invention to provide a method for manufacturing a high-voltage ceramic capacitor, thereby realizing a high-voltage ceramic capacitor with excellent reliability.

To this end, the present invention provides that at least one lead terminal to be attached to an electrode of a high-voltage ceramic capacitor body is attached via a connecting terminal having a larger cross-sectional shape than the lead terminal, and the lead terminal side attached via this connecting terminal is provided. Attach a spacer to the electrode surface at a position that is approximately symmetrical with respect to the mounting position of this lead terminal and the center point on this mounting electrode surface, and place the lead terminal attached via the connection terminal on the bottom surface of the mold for molding. The capacitor body is molded by inserting it into the through hole and fitting the spacer into the recess formed on the inner bottom surface of the mold so that a predetermined space is formed between the connecting terminal and the spacer and the inner bottom surface of the mold. The resin is placed in a mold, and resin is injected into the mold.

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

In FIG. 4, reference numeral 21 denotes a high-voltage porcelain capacitor body, and silver paste or the like is applied by screen printing to the opposite surfaces of the body and baked, and the electrodes 22, 2
form 3. The electrodes 22 and 23 can also be formed by other means such as plating or vapor deposition using appropriate electrode materials. Next, lead terminals 26 and 27 are connected to the surfaces of the electrodes 22 and 23 via connection terminals 24 and 25 by soldering or the like. These connection terminals 24 and 25 are used to increase the adhesive strength with the electrode surfaces of lead terminals 26 and 27, and to form a predetermined space between the inner bottom surface of a mold and the capacitor body, which will be described later. , lead terminals 26, 27
The lead terminal 26,
It is connected to the tip of No. 27 with solder or the like.
Note that it is also possible to form the lead terminals and the connection terminals as one piece instead of forming them as separate pieces. Next, a spacer 28 made of an insulating material such as porcelain is pasted with adhesive on the surface of the electrode 23 to which one lead terminal 27 is attached, at a position away from that lead terminal. Note that this spacer 28 is attached at a position approximately symmetrical to the lead terminal 27 with respect to the center point on the surface of the electrode 23. Further, the spacer 28 may be attached to the electrode surface before the lead terminals 26 and 27 are attached. Further, the material of the spacer 28 may be metal, and in this case, it can be attached to the electrode surface by soldering. The lead terminal 26 on the side to which the spacer 28 is not attached does not necessarily need to be attached to the surface of the electrode 22 via the connection terminal 24, and may be attached directly if adhesive strength is not a problem.
The high-voltage ceramic capacitor body 21 with the lead terminals and spacers attached in this manner is placed in a molding die 29 as shown in FIG. In other words, this mold 29 has a through hole 30 formed at its bottom to draw out the lead terminal to the outside, and a recess 31 having a depth shallower than the height of the spacer 28 at a position away from the through hole 30 on the inner bottom surface. It is formed. Therefore, the capacitor body 21 is formed by inserting the lead terminal 27 into the through hole 30 to bring the end surface of the connecting terminal 25 into contact with the inner bottom surface of the mold, and by fitting the tip of the spacer 28 into the recess 31. It is placed in the mold with a predetermined space substantially parallel to the inner bottom surface formed therebetween. In addition,
If the width of the recess 31 formed on the inner bottom surface of the mold 29 is made larger on the side corresponding to the longitudinal direction of the capacitor body than the width of the spacer 28, the accuracy of the mounting position of the lead terminal and spacer can be increased accordingly. can be made looser. As is clear from the description of the arrangement of the capacitor body 21 in the mold 29, the height of the spacer 28 is set to be approximately equal to the height of the connection terminal 25 plus the depth of the recess 31. has been done. In this manner, a resin 32 such as an epoxy resin is injected into the mold 29 in which the capacitor body 21 is placed and hardened. The appearance of the high-voltage ceramic capacitor thus obtained is shown in FIG. As is clear from this figure, the part of the spacer 28 that was fitted into the recess 31 on the inner bottom surface of the mold is exposed from the surface of the resin 32, but the depth of the recess 31 on the inner bottom surface of the mold is made as shallow as possible. If you do so, it will not be a hindrance especially when using the capacitor. It is also possible to increase the depth of the recess 31 to increase the exposed portion of the spacer from the resin surface, and to actively utilize the exposed portion for positioning when arranging the capacitor. Note that the planar shape of the spacer may be any shape such as a circle, a triangle, etc. in addition to the quadrangle shown in the figure.

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. FIGS. 4 and 5 are a plan view and a vertical cross-sectional side view of a main part for explaining a method for manufacturing a high-voltage ceramic capacitor according to an embodiment of the present invention, FIG. 6 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... Spacer, 29...
Mold die, 30...through hole, 31...dent,
31...Resin.

Claims (1)

[Scope of Claims] 1. A high-voltage ceramic capacitor in which lead terminals are attached to each of the electrodes provided on both sides of a rectangular plate-shaped high-voltage ceramic capacitor body, and the outer peripheral surface of the capacitor body is resin-molded. A manufacturing method comprising: (a) forming electrodes on both sides of a high-voltage ceramic capacitor body; (b) forming at least one of a pair of lead terminals to be attached to the electrodes formed on both sides of the high-voltage ceramic capacitor body; Step of attaching via a connecting terminal having a large cross-sectional shape, c. At least one attachment electrode surface of the connection terminal attached to the electrode of the high-voltage ceramic capacitor body, the attachment position of the connection terminal and the attachment electrode surface A step of attaching the spacer at a position approximately symmetrical with respect to the center point of the spacer, d. Fitting the spacer into a recess shallower than the height of the spacer formed on the inner bottom surface of the mold, and attaching the spacer to the mounting surface of the spacer. The end surface of the connection terminal is brought into contact with the inner bottom surface of the mold, the lead wire attached to this connection terminal is inserted into the through hole formed in the mold bottom surface, and the connection terminal and the spacer are connected to the mold inner bottom surface. a step of placing the high-voltage porcelain capacitor element in a molding die so as to form a predetermined space; A method for manufacturing a high-voltage porcelain capacitor, comprising the steps of resin-molding the capacitor.