JPH0537466Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a feedthrough capacitor with improved terminal shape and electrical and mechanical connection structure between the inner peripheral surface electrode and the terminal.

[Conventional technology]

For example, in feedthrough capacitors used in high-voltage circuits, it is necessary to increase the withstand voltage, so electrodes are formed on the inner and outer surfaces of a cylindrical ceramic body to extract the capacitance, and a metal terminal is inserted into the center hole. structure is known. An example of the manufacturing process for this type of feedthrough capacitor will be explained with reference to FIG.

A cylindrical porcelain body 3 with electrodes 1 and 2 formed on the inner and outer circumferential surfaces is prepared, and the surface is plated with solder or tin into the center hole of the porcelain body 3 from the direction of the arrow. Insert the metal terminal 4. After that, the electrode 1 on the inner peripheral surface side and the metal terminal 4 are connected by soldering.
A feedthrough capacitor is obtained by electrically connecting the metal terminals 4 and mechanically joining and fixing the metal terminals 4 to the ceramic body 3.

However, due to the above-mentioned solidification shrinkage of the solder during soldering and cooling shrinkage of the solder and metal terminal 4 in a cold/hot cycle environment, a force that tries to pull the electrode 1 on the inner peripheral surface side toward the center of the cylindrical body is generated. may occur. As a result, there was a problem in that the electrode 1 on the inner circumferential side rose from the inner circumferential surface of the porcelain body 3, and if exposed too much, it would peel off.

In order to reduce the above-mentioned force, it is sufficient to reduce the area of the region connected by solder. Therefore, as shown in the plan view and partially cutaway front view in FIGS. 3 and 4, an attempt has been made to apply a solder resist material 5 to a part of the outer surface of the metal terminal 4 as shown. .

That is, in the outer surface portion of the metal terminal 4 that is in contact with the electrode 1 on the inner peripheral surface side of the porcelain body 3, a portion 4
If the solder resist material 5 is applied except for the part a, the metal terminal 4 and the electrode 1 are soldered only in the part 4a, and the above-described force on the electrode 1 can be reduced.

The resist material 5 is usually applied by (a) brush painting called handling, (b) tampo printing applied by pressing an elastic material carrying the resist material, and (c) applying the resist material to the outer peripheral surface of a roller made of an elastic material. A method is used in which the resist material is transferred by applying a resist material to the metal terminal 4 and making it contact the metal terminal 4 while rotating the roller.

[Problem that the invention attempts to solve]

However, handling method a has poor workability, it is difficult to keep the dimensions of the printing area of the resist material constant, that is, the printing angle and printing length, and it is also difficult to make the film thickness of the resist material uniform. There was a problem.

In addition, in pad printing in b, it is not possible to make the film thickness of the resist material 5 sufficiently thick, and since the pad is pressed from a certain direction, it is not possible to print over the entire circumference of the metal terminal 4. There was a problem.

Furthermore, in the roller transfer method of c, the metal terminal 4
Although it is possible to print over the entire circumference of the resist material, it is not easy to form a region where the resist material is not applied in a portion in the circumferential direction, such as the portion 4a in FIGS. 3 and 4.

Therefore, it is an object of the present invention to provide a feedthrough capacitor having a structure that allows a solder resist material to be applied with high precision and a uniform thickness.

[Means for solving problems]

The feedthrough capacitor of the present invention includes a cylindrical porcelain body with electrodes formed on the inner and outer circumferential surfaces, and a center hole of the cylindrical porcelain body that is penetrated through and electrodes formed on the inner periphery. A recess is formed in a part of the outer surface of the porcelain body that is in contact with the electrode on the inner peripheral surface side of the porcelain body, and the inner circumference excluding the recess is It is characterized in that a solder resist material is applied to the outer surface portion in contact with the electrode on the surface side, and is soldered to the electrode on the inner peripheral surface side in the recess.

[Effect]

In this invention, by devising the shape of the outer surface of the terminal, that is, by providing a recess, a part to which solder resist material is not applied is configured, and thereby the remaining outer surface part that contacts the electrode on the inner peripheral surface side is This makes it possible to apply a resist material with high precision using various resist material application methods.

[Explanation of Examples]

FIG. 1 is an exploded perspective view for explaining one embodiment of the present invention. To obtain the feedthrough capacitor of this embodiment, a cylindrical ceramic body 13 made of a dielectric ceramic material and having electrodes 11 and 12 formed on its inner and outer circumferential surfaces is prepared. A metal terminal 14 is inserted into the center hole of the porcelain body 13 in the direction of the arrow, and the metal terminal 14 and the electrode 11 on the inner peripheral surface are electrically connected by soldering.

A feature of this embodiment is that a metal terminal 14 having a recess 16 shown in FIGS. 5 and 6 is used. The recess 16 is a metal terminal 14
It is formed by pressing a part of the material, so-called crushing. However, it is also possible to use other processing means, such as cutting or polishing.

Returning to FIG. 1, in the outer surface portion of the metal terminal 14 that contacts the electrode 11 on the inner peripheral surface side of the porcelain body 13,
A solder resist material 15 is applied to the remaining portion except for the recessed portion 16 described above. Therefore, metal terminal 1
4 is inserted into the porcelain body 13 and soldered, it is electrically connected to the electrode 11 on the inner circumferential surface only at the recessed part 16. The force due to cooling shrinkage of the solder and metal terminal 14 does not become very large. Therefore, it is possible to effectively prevent floating and peeling of the electrode 11 on the inner peripheral surface side.

Note that, as is clear from FIG. 1, the resist material 15 is applied to the bottom part 16a of the recess 16. In this case, the bottom portion 16a of the recess 16 functions as a solder flow stopper during soldering.

Moreover, the above-described resist material 15 can be applied to desired dimensions and uniform thickness using various resist material application methods.

That is, when the roller transfer method described above is used, as schematically shown in FIG.
is formed, so that the metal terminal 14 and the roller 17 with the resist material 15 applied to the outer peripheral surface
By rotating and press-contacting each in the direction of the arrow shown in the figure, it is possible to accurately apply the coating to a desired area of the outer surface of the metal terminal 14 excluding the recess 16 over the entire circumference of the metal terminal 14. . Afterwards,
It becomes possible to apply the solder resist material using the roller transfer method, which has excellent workability, can obtain a uniform film thickness, and also enables highly accurate printing of the resist material.

Note that the roller 17 may be made of various elastic materials such as neoprene rubber, butyl rubber, or nitrile rubber.

Further, it is preferable that the depth of the recess 16 is, for example, 0.05 mm or more. If it is shallower than this,
This is because there is a possibility that the resist material 15 enters into the recess.

Furthermore, it is possible to apply the resist material 15 using the remaining methods described above, that is, the handling method and the tampo printing method. For example, by making the area of the recess 16 a little smaller and deeper, it is possible to print the resist material 16 only in the position excluding the recess by pad printing. The same applies to handling methods. However,
For workability and uniformity of film thickness, it is preferable to use a roller transfer method.

Note that as the resist material, any material such as epoxy resin, polyimide resin, fluororesin, phenol resin, or melamine resin can be used.

Furthermore, although the recess 16 was formed in a shape that recessed from the outer surface of the metal terminal 14 toward the center, it could reach the outer surface on the opposite side of the metal terminal as long as it had a shape that could prevent the resist material from entering. It may be a through recess.

Furthermore, the expression "concavity" is relative, and therefore, conversely, a protrusion is formed that protrudes outward from the outer surface portion of the terminal to which no resist material is applied, and a resist material is applied to the protrusion. In that case, the outer surface portions other than the convex portions shall mean the "concave portions" in the present invention.

In addition, in the above embodiment, the round bar-shaped metal terminal 14
However, it is possible to use a metal terminal of any shape such as a prismatic shape or a tubular shape. Similarly, the porcelain body 13 may be of any shape such as a rectangular tube shape.

[Effect of idea]

According to the present invention, since a recess is formed in a part of the outer surface of the metal terminal that is in contact with the electrode on the inner peripheral surface of the porcelain body, the solder resist material is applied to the recess that is in contact with the electrode on the inner peripheral surface. It is applied exactly to the remaining outer surface part except for. Therefore, with conventional feedthrough capacitors, it was not easy to leave resist material unapplied to a part of the circumference.Using the roller transfer method, we applied solder resist material efficiently and with high precision to a uniform film thickness. can do. Further, even when a resist material application method such as a pad printing method or a handling method is used, since the recessed portion is provided, it becomes possible to apply the solder resist material to the surface of the metal terminal with accurate dimensions.

Therefore, it is possible to realize a feedthrough capacitor that has excellent reliability and is less likely to malfunction under a thermal cycle environment.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view for explaining the process of obtaining an embodiment of the present invention, Fig. 2 is an exploded perspective view for explaining the process of obtaining a conventional feedthrough capacitor, and Fig. 3 is an exploded perspective view for explaining the process of obtaining a conventional feedthrough capacitor. FIG. 4 is a partially cutaway front view of the metal terminal for explaining the application pattern, FIG. 5 is a front view of the recess formed in the metal terminal in an embodiment of the present invention, FIG. 6 is a side view, and FIG. 7 is a schematic front view for explaining an example of a method of applying a resist material. 11 and 12 are electrodes, 13 is a ceramic body, 14 is a terminal, 15 is a solder resist material, and 16 is a recess.

Claims (1)

[Claims for Utility Model Registration] A cylindrical porcelain element having electrodes formed on its inner circumferential surface and an outer periphery; A recess is formed in a part of the outer surface of the terminal that is in contact with the electrode on the inner peripheral surface side of the porcelain body, and a recess is formed in a part of the outer surface of the terminal that is in contact with the electrode on the inner peripheral surface side of the porcelain body. A feedthrough capacitor, characterized in that a solder resist material is applied to an outer surface portion in contact with the electrode on the inner peripheral surface side, and the portion is soldered to the electrode on the inner peripheral surface side in the recess.