JPH05827B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a hermetic terminal that penetrates a closed container such as a vacuum container or a pressure container.

``Conventional technology'' Sealed electrical terminals used in sealed containers such as vacuum vessels and pressure vessels are made by combining an insulator such as ceramics or glass such as alumina with a metal such as Kovar, which has a coefficient of thermal expansion similar to that of the insulator. Hermetic terminals are used. The reason why metals such as Kovar are used in hermetic terminals is that ordinary metals have very different coefficients of thermal expansion from insulators such as ceramics and glass. This is because cracks occur at the joint.

FIG. 9 shows an example of a conventional hermetic terminal.
An electric terminal 102 made of metal such as Kovar is inserted into the opening of a stainless steel container 101, and a cylinder 103 made of Kovar or the like is fitted, and an insulator 104 made of ceramic or glass for electrical insulation is interposed and sealed. Electrical terminal 102 and insulator 104, insulator 1
04 and the cylindrical body 103 are filled with brazing filler metals 105 and 1, respectively.
Join with 06. The brazing filler metal 105 used here,
Reference numeral 106 indicates gold solder, silver solder, or a brazing material that does not require metallization treatment on the ceramics or glass to be bonded. Furthermore, the cylindrical body 103 is
Weld to 01. Here, since the electrical terminal 102, the insulator 104, and the cylindrical body 103 have similar coefficients of thermal expansion, cracks will not occur between the electrical terminal 102 and the insulator 104, and between the insulator 104 and the cylindrical body 103 even if the temperature changes. Does not occur. Moreover, the cylinder 103 and the container 101 are
Because it has elasticity, it absorbs the difference in thermal expansion and does not crack even when the temperature changes. In this way, a through-hermetic electrical terminal is formed which maintains hermeticity even when the temperature changes.

"Problem to be Solved by the Invention" Recently, containers made of aluminum or aluminum alloy, which are less likely to generate gas, have been increasingly used as ultra-high vacuum containers. Aluminum or aluminum alloy has a much lower melting point than Kovar, and if joined too slowly, aluminum or aluminum alloy will melt.

As described above, although aluminum and Kovar have very different melting points, they can be welded by laser welding, which can rapidly heat and cool and quickly complete the bond. However, solidification cracks are likely to occur due to thermal stress that occurs with rapid heating and rapid cooling, and airtight leaks are likely to occur. On the other hand, the 10th
An electrical terminal 112 made of metal such as Kovar is inserted into the opening of a container 111 made of aluminum or aluminum alloy shown in the figure, and an insulator 113 made of ceramics such as alumina or glass is interposed between the electrical terminal 112 and the insulator 113. 113 and the container 111 are joined using brazing materials 114 and 115. Then, there is a large difference in thermal expansion between the aluminum or aluminum alloy container 111 and the insulator 113, and cracks occur between the two when the temperature changes. As described above, it is impossible to directly replace the stainless steel container 101 shown in FIG. 9 with the aluminum or aluminum alloy container 111 shown in FIG. 10, which is desired to be used, in view of solidification cracking.

"Means for Solving the Problems" In view of the above circumstances, the present invention has been developed to replace the insulator through which the electrical terminal is inserted with an insulator in order to prevent cracks from occurring in the insertion portion of the electrical terminal in the opening of the container. Connecting bodies such as Kovar, which have similar coefficients of thermal expansion, are joined using a brazing material, a layer is formed on at least one of the facing surfaces of the container and the connecting body, and the outside of the connecting body is joined to the container by welding. A connecting body that can absorb stress and strain due to differences in thermal expansion is interposed between the two. In addition, it is also possible to provide a stress and strain absorbing structure in a part of the container, so that both the connecting body and a part of the container,
Alternatively, either one of them absorbs stress and strain.

"Operation" A connecting body with a coefficient of thermal expansion similar to that of the insulator is bonded to the insulator using a brazing material, and a layer is interposed between the connecting body and the container is joined by welding.The connecting body absorbs stress and strain due to the difference in thermal expansion. do. Furthermore, if a part of the container has a structure that absorbs stress and strain, the stress and strain will be absorbed there.

"Examples" The present invention will be described in detail below based on Examples.

In FIG. 1, an insulator 2 made of ceramic or glass such as alumina is inserted into the opening of a container 1 made of aluminum or aluminum alloy, and an electrical terminal 3 made of metal such as Kovar is passed through the center of the insulator 2. A spherical stress- and strain-absorbing connector 4 made of a material having a coefficient of thermal expansion similar to that of the insulator 2 is interposed between the insulator 2 and the container 1 and joined. The electrical terminal 3 and the insulator 2, and the insulator 2 and the connecting body 4 are joined with brazing materials 5 and 6, respectively. The brazing fillers 5 and 6 are gold brazing, silver brazing, brazing filler metal that does not require metalizing the ceramics or glass to be bonded, or the like. A plating layer 7 of nickel or the like is provided on the opening of the container 1 or on the outside of the connecting body 4 or both, and the container 1 and the connecting body 4 are laser welded via the plating layer 7.

As a connecting body, not only the spherical connecting body 4, but also
The circular wave-like connecting body 14 shown in FIG. 2, the bottomed cylindrical connecting body 24 shown in FIGS. 3 and 4, the bottomed cylindrical connecting body 34 shown in FIGS. There is a protruding spherical connector 44. In FIG. 8, an absorbent support 8 is shown facing outward at the opening of the container 1.
The electric terminal 3 is inserted into the absorption support 8 through the insulator 2, and a thin disc-shaped connecting body 54 is provided between the insulator 2 and the absorption support 8 to prevent shape distortion due to temperature changes. It is shaped to make it easy to cause.
Both the absorbing support 8 and the disc-shaped connecting body 54 are connecting bodies that absorb strain and stress, and although the case where both are provided has been described, only one of them absorbs strain and stress, and the other is a rigid body. It can also be shaped like

In the above embodiment, the aluminum or aluminum alloy container and the connecting body were joined by laser welding, but the method is not limited to gas welding, electric welding,
It may be brazed. Furthermore, an example has been described in which a nickel layer is interposed during laser welding of the container and the connecting body, but any material other than nickel may be used as long as it is easily welded with Kovar or the like. Further, the plating may be electroless plating, electric plating, etc., such as electroless nickel-1% by weight boron plating or electroless nickel-8% by weight phosphor plating. Furthermore, instead of plating, the nickel layer may be formed by epitaxy, sputtering, vapor deposition, solid phase diffusion, or the like. Note that a layer of a material that is easily welded to the container may be provided on the connecting body instead of on the container by plating or the like. Alternatively, layers may be provided on both.

"Effects of the Invention" Since the present invention is configured as described above, it is possible to prevent cracking even if there is a temperature change in a container such as aluminum or aluminum alloy, which is excellent as an ultra-high vacuum container and cannot be directly welded with Kovar. , hermetic terminals can be attached. It is extremely effective for industrial and academic uses of ultra-high vacuum. It is possible to provide a durable hermetic terminal that does not crack due to differences in thermal expansion even when the temperature changes.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view of a specific embodiment of the present invention, FIG. 2 is a partially sectional side view of another embodiment, and FIG. 3 is a partially sectional side view of another embodiment. 4 is a plan view of FIG. 3, FIG. 5 is a partially sectional side view of another embodiment, FIG. 6 is a plan view of FIG. 5, and FIG. 7 is a plan view of FIG. FIG. 8 is a partially sectional side view of another embodiment. FIG. 8 is a partially sectional side view of still another embodiment. 9 and 10 are vertical cross-sectional views of conventional hermetic terminals. 1... Container, 2... Insulator, 3... Electrical terminal,
4, 14, 24, 34, 44, 54...connected body,
6...Brazing, 7...Plated layer (example of layer), 4
... Spherical connected body, 14 ... Circular wavy connected body, 2
4... Bottomed cylindrical connecting body, 34... Bottomed square cylindrical connecting body, 44... Spherical connecting body protruding inward,
54... Thin disc-shaped connector, 8... Absorption support.

Claims (1)

[Claims] 1 A hermetic terminal installed through a sealed container made of aluminum or aluminum alloy, in which the electrical terminal is inserted into the opening of the sealed container via an insulator, and the thermal expansion coefficient of the insulator is set between the insulator and the container. A connecting body made of Kovar having a similar coefficient of thermal expansion is interposed, the inside of the connecting body is joined to an insulator by brazing, and a nickel layer is formed by plating on at least one of the facing surfaces of the connecting body and the container, and the outside of the connecting body is Hermetic terminals joined to a sealed container by laser welding