JPS5835356B2 - Kimitsutanshinoseizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an airtight terminal, particularly an airtight terminal for cold pressure welding.

As shown in FIGS. 1 and 2, a known airtight terminal for cold pressure welding has a metal eyelet 4, in which a lead wire 2 is sealed with glass 3, brazed inside a metal case 1, and a metal cap. 5
The flanges 1' and 5' are cold welded together to secure them together.

6 is an element attached to the tip of the lead wire 2.

By the way, in the airtight terminal of the above structure, the eyelet 4 is brazed to the opening τ' of the lower plate of the case 1 at the stepped part A, but this is particularly useful for airtight terminals of crystal oscillators of quartz watches, etc. In the case of an ultra-small airtight terminal, the gap t between the inner circumferential surface of the case 1 and the outer circumferential surface of the eyelet 4 is structurally extremely narrow, so the soldering material 7 of the brazing part crawls into the gap t due to capillary action. As shown in FIG. 2, the brazing material 7 fills the space between the case 1 and the eyelet 2.

Usually, in this type of airtight terminal, as shown in FIG. 1, the case 1 and the eyelet 4 have an elliptical shape, and the two lead wires 2 are sealed with glass along the long axis of the eyelet 4.

And between the inner peripheral surface of the case 1 and the outer peripheral surface of the eyelet 4,
In particular, leave enough space in the gap l between both ends 8, 8 of the long diameter, put the brazing material 7 into this gap l, heat the whole thing, and connect the stepped part l of the eyelet 4 and the opening 1" of the bottom plate of the case 1. It is soldered.

During this brazing, there is no problem if the melted brazing material 7 spreads over the entire circumference of the step 4 of the eyelet and the opening 1'' of the case 1, but as mentioned above, other than the both ends 8, 8, the case 1 Since the gap t between the inner circumferential surface of the eyelet 4 and the outer circumferential surface of the eyelet 4 is extremely narrow, a portion of the eyelet 4 crawls into the gap t.

Therefore, the amount of brazing material 7 to be introduced is increased in anticipation of the amount of climbing, and the aim is to ensure that the entire circumference of the case opening and the eyelet step is brazed.

As the amount of brazing material increases in this way, more and more brazing material creeps into the gaps, a vicious cycle that repeats, and as a result,
As shown in Fig. 2, unnecessary parts are completely filled with brazing material.

Although this improves airtightness and mechanical strength, it has the following drawbacks.

That is, when the cap 5 is fixed to the case 1 of the airtight terminal having the above structure by cold pressure welding, as shown in FIG. 5 occurred.

In particular, the inward deformation stress y acts directly on the sealing glass 3 through the brazing material γ and the eyelet 4, leading to breakage of the glass 3.

This is due to the fact that the gap between the case 1 and the eyelet 4 is filled with brazing material 7, which causes a decrease in the reliability of the airtight terminal, especially the airtight terminal for cold pressure welding. ing.

This invention solves the above-mentioned drawbacks of the conventional hermetic terminal, and will be described in detail with reference to FIG.

This invention takes advantage of the property of brazing materials such as silver soldering material that they do not wet the surface of the oxide film, and when brazing the outer circumferential surface of the eyelet or the inner circumferential surface of the case, an oxide film is formed on the surface other than the part. By brazing the two with an oxide film formed, it is possible to prevent the brazing material from creeping up into the gap between the outer peripheral surface of the eyelet and the inner peripheral surface of the case.

FIG. 3 shows the case where an oxide film 3 is formed on the eyelet 4.
An oxide film may be formed on the inner peripheral surface of the case 1.

The eyelet 4 having the oxide film 9 on the outer peripheral surface as shown in FIG. 3 can be manufactured, for example, by the following method.

That is, as shown in FIG. 4, nickel or copper plating layers 41 and 41 are formed on both upper and lower surfaces of a plate member 40 made of 426 alloy containing nickel and chromium, for example, to obtain the eyelet 4 by press molding. This is pressed to punch out an eyelet 4 having a stepped portion 4' as shown in FIG.

In the eyelet 4 thus obtained, the 426 alloy is exposed only on the outer peripheral surface and the inner peripheral surface of the hole, and the remaining portion is covered with a nickel or copper plating layer 41.41.

After this, when heated in a hydrogen atmosphere with controlled oxygen partial pressure,
The exposed chromium component in the 426 alloy is oxidized, and oxide films 9, 9' are formed only on the outer peripheral surface of the eyelet 4 and the inner peripheral surface of the hole.

Therefore, the lead wire 2 may be sealed with the glass 3 as shown in FIG. 1 by utilizing the oxide film 9 on the inner peripheral surface of the hole.

However, the oxide film may be formed in the necessary portions using any other suitable method.

This oxide film may be formed on the entire surface of the eyelet or the case, and then the oxide film may be removed only from the lower part 10, or the oxide film may be formed only on the necessary portions using another method.

After brazing, if the oxide film is left for a long time, it will turn into powder and peel off, which will have a negative effect on the performance of the airtight terminal. Therefore, before brazing, remove the oxide film with an appropriate solution and then plate it. is preferable.

As explained above, the present invention forms an oxide film on the outer circumferential surface of the eyelet in which the lead wire is sealed with glass or on the inner circumferential surface of the case, and on the parts other than the brazing part, and makes the oxide film exist. Since the eyelet and the case are brazed together in this state, the presence of the oxide film prevents the brazing material from creeping into the gap between the eyelet and the case, allowing a gap to be formed in that area.

Therefore, the presence of the above gap can completely eliminate cracks in the sealing glass that occur during cold pressure welding between the cap and the case, creating an airtight terminal for cold pressure welding with excellent airtightness and reliability. can be provided.

[Brief explanation of drawings]

FIG. 1 is a top view showing a general example of a conventional hermetic terminal for cold pressure welding, and FIG. 2 is a sectional view thereof. FIG. 3 is a sectional view of the airtight terminal according to the present invention. FIGS. 4 to 7 are cross-sectional views at each step for explaining one embodiment of the eyelet manufacturing method. 1...Case, 2...Lead wire, 3.
... Gala 8 4 ... Eyelet, 5 ...
- Cap, 6...Element, 7...Raw material, 9...Oxide film.

Claims (1)

[Claims] 1. An oxide film is formed on the outer peripheral surface of the eyelet where the lead wire is sealed with glass or on the inner peripheral surface of the case, and on parts other than the brazed part, and the eyelet and the case are connected with the oxide film present. A method for manufacturing an airtight terminal, characterized by brazing.