JPH0715128Y2 - Feedthrough capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an improvement of a feedthrough capacitor.

2. Description of the Related Art Conventionally, a disk penetrating capacitor as shown in FIG. 2 will be described. A large-diameter cylindrical portion is provided with an external metal fitting 1 having a stepped shape from a large-diameter cylindrical portion 1a and a small-diameter cylindrical portion 1b. A ceramic dielectric 2 is housed in the cylinder of 1a, a conductive conductor 3 is arranged in the center of the ceramic dielectric 2, and a ceramic dielectric is arranged in each of the large-diameter cylinder 1a and the small-diameter cylinder 1b. It is known that the insulating resin 4 and 5 such as epoxy and phenol are individually filled and cured from above and below via 2 (JP-A-56-133817).

In the feedthrough capacitor, the inner diameter of the small-diameter cylindrical portion 1b is
Compared with 2.8 mm or 2.4 mm, which is small, as a through conductor
It has a large shaft diameter of about 0.6 to 0.8 mm. For this reason, it is difficult to automatically fill the insulating resin such as epoxy and phenol because the space between the two is extremely narrow. Also, when filling the insulating resin into the cylinder of the small-diameter cylindrical portion 1b, Inevitably adheres to the shaft portion side of the through conductor protruding from the small-diameter cylindrical portion 1b to the outside.

Since the insulating resin such as epoxy or phenol is a thermosetting resin, if it adheres to the through conductor and cures, it does not melt under normal soldering conditions and needs to be removed by relying on mechanical means. In particular, when it is inserted into the printed circuit board from the small-diameter cylindrical part of the external metal fitting that is soldered and fixed to the chassis, etc., and adheres to the tip side of the through conductor that is soldered and fixed to the electrode, insulating resin such as epoxy or phenol As described above, it does not melt at the soldering temperature, which is an obstacle to electrically connecting the through conductor and the electrode for soldering.

In order to avoid the adhesion of the insulating resin, the insulating resin is not filled in the cylinder of the small-diameter cylindrical portion, and the surface of the ceramic dielectric exposed in the cylinder of the small-diameter cylindrical portion is preliminarily printed with an insulating resin or other insulating material. Providing an insulating coating by coating has been proposed (Shokaisho 60-41038).

In the feedthrough capacitor, an insulating coating made of an insulating material is provided in advance on the surface of the porcelain dielectric in the gap between the inner edge of the electrode and the hole edge of the through conductor hole, and the porcelain provided with this insulating coating is provided. Since the dielectric is housed and arranged within the diameter of the large-diameter cylinder, and the through conductor is inserted through the center hole of the ceramic dielectric, the center hole of the ceramic dielectric through which the through conductor is inserted and the axis of the through conductor There is a risk that a gap will remain between.

Also, in this feedthrough capacitor, the electrode surface of the porcelain dielectric and the inner surface of the small-diameter cylinder are fixed by soldering in the vicinity of the insulating coating. In order to avoid a short circuit with the conductor, the insulating coating must be made of a material that does not melt at the soldering temperature.

In the through-type capacitor described above, the insulating resin filled in the cylinder of the large-diameter cylindrical portion and the insulating coating attached to the gap can maintain moisture resistance to some extent, but these insulating resins and coatings are relatively porous. In addition, since a gap remains between the insulating coating and the through conductor, there is still concern about the moisture resistance.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the present invention, an insulating resin such as epoxy or phenol is filled only in the cylinder of the large-diameter cylinder portion, and not in the cylinder of the small-diameter cylinder portion. Moisture resistance is sufficiently ensured by providing it in each cylinder of the cylindrical part and the small diameter cylindrical part, and even if the insulating coating is attached on the axis of the through conductor, soldering is performed to electrically connect the through conductor. It is an object of the present invention to provide a feedthrough capacitor improved so as not to cause any trouble.

Means for Solving the Problems In a feedthrough capacitor according to the present invention, an external metal fitting having a stepped shape is provided from a large-diameter tubular portion and a small-diameter tubular portion, and a ceramic dielectric is provided inside the large-diameter tubular portion. Is a through-type capacitor in which a through conductor is placed in the center, and a large-diameter cylinder is filled with an insulating resin and hardened, and a small-diameter cylinder is not filled with an insulating resin. A tube containing a surface of insulating resin from the base of the through conductor exposed in the cylinder of the large-diameter cylinder part, which is a film of molten wax or silicon oil of a material that has insulation and moisture resistance and melts at the soldering temperature. Inside,
The small-diameter cylindrical portion is formed by covering the base of the through conductor exposed in the cylinder and the inner surface of the cylinder including the surface of the porcelain dielectric.

Action In this feedthrough capacitor, after the whole is assembled as a capacitor, it is exposed inside the cylinder of the small diameter cylinder along with the inner surface of the insulating resin from around the root of the through conductor exposed in the cylinder of the large diameter cylinder. The surface of the porcelain dielectric is covered with a film of molten wax or silicon oil from around the root of the through conductor. Since the molten wax or silicon oil has insulation and moisture resistance, the water repellency is enhanced to prevent moisture and insulation. It is possible to sufficiently secure reliability such as sex.

Even if this molten wax or silicon oil adheres to the through conductor, the wax melts at the temperature during soldering, and the silicon oil has a large fluidity and becomes thin as a film portion, so the electrical conductivity of the through conductor is reduced. It does not become an obstacle to soldering that keeps electrical continuity.

The molten wax becomes solid when the temperature returns to room temperature, and the silicone oil has a low fluidity. Therefore, the moisture resistance and the insulating property of the molten wax or silicone oil coating are not impaired.

Example The following is a description with reference to FIG.

This through-type capacitor is a disk-through type, and is equipped with an external metal fitting 10 having a stepped shape from a large-diameter cylindrical portion 10a and a small-diameter cylindrical portion 10b, and a through conductor 11 is provided at the center of a ceramic dielectric 12 at the center. It is assembled by inserting it into the hole. A disk-shaped one is used as the porcelain dielectric 12, and it is assembled and arranged in the cylinder of the large-diameter cylinder 10a. The penetrating conductor 11 has a stopper flange 11b on the substantially middle side of the axis 11a, holds the porcelain dielectric 12 with the stopper flange 11b, and fits the axis 11a in the center hole of the porcelain dielectric 12 to form the porcelain dielectric 12. It is assembled in the center. The porcelain dielectric 12 has electrodes 13a and 13b on both sides, and melts the solder attached in advance by heater heating or high-frequency dielectric heating to fix the electrodes 13a and 13b to the inner surface of the large-diameter cylindrical portion 10a and the retaining collar 11b. Therefore, it is electrically connected to the external fitting 10 and the through conductor 11.

In the feedthrough capacitor, the insulating resin 14 such as phenol or epoxy is filled and hardened only in the cylinder of the large-diameter cylinder portion 10a. Instead of filling the insulating resin in the cylinder of the small-diameter cylindrical portion 10b, a coating film 15 of highly water-repellent molten wax or silicone oil having insulation and moisture resistance is provided in the small-diameter cylindrical portion 10b. ing. The molten wax or silicon oil coating 15 is provided as a coating covering the inside of the small-diameter cylindrical portion 10b including the surface of the porcelain dielectric 12 from the base of the through conductor 11 exposed inside the small-diameter cylindrical portion 10b. ing. At the same time, the molten wax or silicon oil coating 15 is formed on the large-diameter cylindrical portion 10a including the surface of the insulating resin 14 from the base of the through conductor 11 exposed in the cylinder.
It is also provided so as to cover the inside of the cylinder of 10a. The moisture-proof coating 15 can be formed so as to cover the entire surface including the outer metal fitting 10 by applying molten wax or silicone oil or immersing it in a solution. However, the molten wax or silicon oil is the small-diameter cylindrical part of the external fitting 10.
Even if it adheres to the axial line portion of the through conductor 11 protruding from 10b, since it melts at the soldering temperature, it does not hinder the electrical connection of the through conductor 11 during soldering.

With the feedthrough capacitor configured in this way, the external metal fitting 1
0, the through conductor 11 and the porcelain dielectric 12 are fixed to each other by soldering, and the insulating resin 14 such as phenol or epoxy is filled in the large-diameter cylindrical portion 10a of the outer metal fitting 10 to prevent the through conductor 11 from being removed. It is constructed to be robust so that it will not occur. However, since the insulating resin 14 is not filled in the small-diameter cylindrical portion 10b of the outer metal fitting 10, it does not adhere to the axial line portion of the through conductor 11 protruding from the small-diameter cylindrical portion 10b.

Instead of filling the insulating resin, the inside of the small-diameter cylindrical portion 10b is covered with the molten wax or silicon oil coating 15 together with the inside of the large-diameter cylindrical portion 10a. Since the molten wax or silicone oil has moisture resistance and insulation properties, it can be configured to have excellent moisture resistance and insulation properties as a whole. Further, even if the molten wax or silicon oil coating 15 is attached to the axial line portion of the through conductor 11,
The molten wax melts at the temperature at the time of soldering, the fluidity of the silicone oil becomes large, and the film portion becomes thin, so that there is no obstacle at the time of soldering for electrical conduction of the through conductor 11. Further, since the molten wax becomes solid when the temperature returns to room temperature, and the silicon oil has low fluidity when the temperature returns to room temperature, the moisture resistance and the insulating property due to these coatings 15 are not impaired.

As described above, according to the feedthrough capacitor of the present invention,
In addition to the insulating resin that fills the inside of the large-diameter cylinder, the melting that forms inside the cylinder of the small-diameter cylinder and inside the cylinder of the large-diameter cylinder can be simplified and can be made inexpensive and small. A wax or silicone oil coating can provide reliability such as moisture resistance and insulation. Further, even if the molten wax or silicon oil adheres to the through conductor, it melts at the soldering temperature or becomes a thin film, so that electrical continuity with other electronic parts can be surely obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view of a feedthrough capacitor according to the present invention, and FIG. 2 is a side sectional view of a feedthrough capacitor according to a conventional example. 10: External metal fitting, 10a: Large diameter tubular part of external metallic fitting, 10b: Small diameter tubular part of external metallic fitting, 11: Through conductor, 12: Porcelain dielectric, 14: Insulating resin, 15: Molten wax or silicone oil coating.

Continuation of the front page (72) Inventor Noriaki Sato 1-13-1 Nihonbashi, Chuo-ku, Tokyo Within TDK Corporation (56) Reference JP-A-49-72649 (JP, A) JP-A-50-136662 ( JP, A) Actual development Sho 60-41038 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A large-diameter cylindrical portion (10a) and a small-diameter cylindrical portion (10b) are provided with an external metal fitting (10) having a stepped shape, and the large-diameter cylindrical portion (10a) has a ceramic dielectric inside the cylinder. (12) is housed, the through conductor (11) is arranged in the center, and the insulating resin (14) is filled and hardened in the cylinder of the large-diameter cylindrical portion (10a) to form the small-diameter cylindrical portion (10b). ) In a feedthrough capacitor in which the inside of the cylinder is not filled with insulating resin, a film of molten wax or silicon oil made of a material that has insulation and moisture resistance and that melts at the soldering temperature (15)
The through conductor (11) exposed in the cylinder of the large diameter cylinder (10a).
The through conductor (11) exposed from the base of the cylinder to the inner surface of the cylinder including the surface of the insulating resin (14) and the cylinder of the small diameter cylinder (10b).
A feedthrough capacitor, characterized in that the inner circumference of the cylinder including the surface of the porcelain dielectric (12) is covered from around the base of the.