JP2001244373A - Airtight terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an airtight terminal wherein a sealing part of a stem and a lead pin is hard to be damaged. SOLUTION: This airtight terminal has the lead pin led from the stem, and the lead pin is provided with a loop of one round or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a hermetic terminal,
In particular, it relates to an airtight terminal having a lead pin.

[0002]

2. Description of the Related Art A hermetic terminal to which a lead pin is attached for supplying a signal voltage to a piezoelectric actuator element has a linear lead pin extending from a stem of the hermetic terminal and the piezoelectric actuator element fixed by soldering. Thus, power is supplied by being electrically connected.

[0003]

However, in the hermetic terminal, the piezoelectric actuator element is displaced by a signal voltage supplied from the lead pin, and the displacement is caused by a soldering portion between the piezoelectric actuator element and the lead pin which are restrained by the lead pin. And the lead pin repeatedly expands and contracts due to the stress caused by the displacement, which causes a problem that the sealing portion between the stem and the lead pin is damaged.

The present invention has been made in view of the above-mentioned problems of the hermetic terminal, and an object of the present invention is to provide an hermetic terminal in which a sealing portion between a stem and a lead pin is hardly damaged.

[0005]

The present inventors have conducted intensive studies to achieve the above object. As a result, if an airtight terminal having a lead pin having a loop is formed, the sealing portion between the stem and the lead pin is damaged. The present inventor has found that it is difficult to obtain an airtight terminal, and has completed the present invention.

That is, the present invention provides (1) a hermetic terminal having a lead pin pulled out from a stem, wherein the lead pin is formed with a loop of one or more turns. 2. The hermetic terminal according to claim 1, wherein (2) the stem and the lead pin are sealed with molten glass or sealed with brazed ceramics. Is the gist. This will be described in more detail below.

As described above, in the hermetic terminal, by providing a loop on the lead pin, the sealing portion between the stem and the lead pin is hardly damaged. The reason is that with this structure, since the loop portion expands and contracts, the displacement acting on the lead pin generated in the piezoelectric actuator element is buffered in the loop portion of the lead pin. As a result, even if the piezoelectric actuator element is displaced, the stem This is because stress that may damage the sealing portion of the lead pin no longer acts, and the sealing portion is less likely to be damaged.

[0008] As a method of sealing the sealing portion, sealing is performed by melting glass or by brazing ceramics. As a result, the sealing portion is hardly damaged.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings and specific embodiments. First, FIG. 1 shows a conventional hermetic terminal having a lead pin, and FIG. 2 shows a hermetic terminal having a lead pin of the present invention. A loop is formed on the lead pin pulled out from the stem of the present invention on the side to which the piezoelectric actuator element is attached.

The method for manufacturing the hermetic terminal will be described below.
First, a stem, a lead pin, and a sealing material shown in FIG. 3 are prepared. The material of the stem is stainless steel, and the material of the lead pin is fernico (product name: Kovar), and the lead pin is passed through the through hole of the stem.

Next, sealing is performed with a sealing material. When sealing with glass, a tube of preformed glass is inserted into the through hole of the stem so as to be in contact with the inside of the through hole of the stem and the outer periphery of the lead pin, and the glass is melted by heating the preformed glass, Sealed.

Specifically, the outer diameter is 3 × the inner diameter is 1 × the length is 6 mm.
A lead pin is passed through a preform glass (manufactured by Nippon Electric Glass Co., Ltd.), and the preform glass is fitted into the through hole of the stem, and heated at a temperature of 800 ° C. in an oxidizing atmosphere to melt the preform glass. Seal tightly.

In the case of sealing with ceramics, a metallized layer is formed on the inner and outer surfaces of a cylinder made of alumina ceramic by a refractory metal method and a nickel plating method, and then the metallized surface and the stem, and the metallized surface and the lead are formed. By brazing the pins, the ceramics and the stem and the ceramics and the lead pins are joined and sealed.

Specifically, outer diameter 3 × inner diameter 1 × length 6 mm
A layer made of molybdenum manganese is formed by baking at a temperature of 1500 ° C. on the inner and outer surfaces of alumina ceramics (manufactured by Nippon Ceratech Co., Ltd.) at a temperature of 1500 ° C. (high-melting point metal method). After that, a lead pin is passed through the inside of the alumina ceramic, inserted into the through hole of the stem, and the silver brazing is heated and melted at a temperature of 800 ° C. in a reducing atmosphere, and the silver brazing is removed from the gap between the ceramic and the stem. And it is poured into the gap between the ceramics and the lead pin and joined, and hermetically sealed.

The lead pin pulled out from the stem may be left as it is if a loop is formed from the beginning. If the loop is not formed, a lead loop is formed as shown in FIG. To have. Thus, an airtight terminal is manufactured. As shown in FIG. 4, a piezoelectric actuator element having a length of 50 mm is fitted inside the two lead pins of the hermetic terminal, and the lead pin and the piezoelectric actuator element are fixed by soldering and electrically connected.

In addition, for comparison, an airtight terminal having a lead pin having no loop formed therein is prepared for comparison, a lead pin fixed to the piezoelectric actuator element is prepared, and the above-described loop is formed. However, the piezoelectric actuator element was driven to repeatedly apply a stress to the sealing portion of the hermetic terminal, and the number of times of stress until breakage was obtained.
Table 1 shows the results.

[0017]

[Table 1]

As is clear from Table 1, in Examples 1 and 2, the sealing portion was not broken even when stress was applied 1 billion times or more.

On the other hand, in Comparative Examples 1 and 2, the number of times the sealing portion was damaged was considerably less than 1 billion times.

[0020]

As described above, with the hermetic terminal of the present invention, highly reliable hermetic sealing can be performed, and the development to electronic parts has been widened.

[Brief description of the drawings]

FIG. 1 is a perspective view of a conventional hermetic terminal.

FIG. 2 shows a perspective view of the hermetic terminal of the present invention.

FIG. 3 shows a cross-sectional view of a component constituting the hermetic terminal.

FIG. 4 is a sectional view of a hermetic terminal to which a lead pin and a piezoelectric actuator element are fixed.

Claims (2)

[Claims] 1. A hermetic terminal having a lead pin drawn out of a stem, wherein the lead pin has a loop formed in one or more turns. 2. The method according to claim 1, wherein the stem and the lead pin are sealed with molten glass or sealed with brazed ceramics.
Hermetic terminal as described.