JPH0746553B2 - Manufacturing method of sealed contact device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a sealed contact device.

[Background technology]

As a contact device used for an electromagnetic switch or a power relay, a sealed contact device having both movable and fixed contacts in a container in which a mixed gas containing hydrogen is sealed has been developed. The enclosed hydrogen has a large thermal conductivity,
Since the action of cooling the arc is strong, the arc generated when the contact is opened can be extinguished in a short time. Therefore, contact wear is reduced and the contact life can be extended. Nitrogen compensates for the decrease in insulation caused by the inclusion of hydrogen. In addition, the sealed contact device has an advantage that oxidation of the contact is difficult to proceed.

In this contact device, a contact terminal having a movable contact on one side and having the other side exposed to the outside of the container is provided so as to be movable in a direction in which the movable contact is brought into contact with and separated from the fixed contact. With the movement of the contact terminal, the contact separation / contact operation is performed.
A space between the contact terminal and the container is hermetically closed by a metal bellows. The bellows and the contact terminal are joined by welding such as laser welding or brazing.

However, this contact device has a problem that the vicinity of the joint between the bellows and the contact terminal is easily damaged. The bellows are cracked. The phenomenon that cracks occur is found not only in the manufacturing process but also in use. When a crack occurs, the hermetically sealed state is impaired and the enclosed mixed gas leaks. Therefore, the arc is not extinguished in a short time, and the contact wear becomes severe.

[Object of the Invention]

In view of the circumstances of the previous term, this invention is not limited to the manufacturing process,
An object of the present invention is to provide a method for manufacturing a sealed contact device that can suppress damage around the joint between the bellows and the contact terminal even after manufacturing.

[Disclosure of Invention]

In order to achieve the above-mentioned object, the present invention, as a result of conducting investigations to investigate the cause of cracking, the bellows is extremely thin, so during welding, only the bellows melts and evaporates. It has been found that cracks are likely to occur and that cracks are likely to occur if there is a gap between the metal bellows (bellow flam) and the contact terminal.

Based on these findings, as a result of continuing studies to devise a way to prevent the occurrence of cracks, a collar-shaped metal member was attached to the contact terminals by sandwiching the joint part of the metal bellows. Then, it was found that the occurrence of cracks can be remarkably reduced by welding from above the metal member, and the present invention has been completed.

Therefore, according to the present invention, the fixed contact and the movable contact are housed in the container, and the contact terminal having the movable contact on one side and the other side exposed to the outside of the container is arranged in a direction in which the movable contact is brought into contact with the fixed contact. It is provided so that it can be moved, and by moving this contact terminal, contact separation and contact operation is performed.
In order to obtain a hermetically sealed contact device in which a metal bellows that hermetically seals between the container and the contact terminal is joined to the contact terminal by welding, and a mixed gas containing hydrogen is sealed in the container, the metal bellows. The method for manufacturing a hermetically sealed contact device is characterized in that a collar-shaped metal member is adhered to the contact terminal by sandwiching the joint portion between and the welding is performed from above the metal member. And

Hereinafter, a method of manufacturing a sealed contact device according to the present invention will be described in detail with reference to the drawings showing a sealed contact device manufactured according to an embodiment.

FIG. 1 shows a cross section of a sealed contact device (hereinafter referred to as “contact device”) manufactured by an embodiment of a manufacturing method according to the present invention. FIG. 2 shows a II-II cross section in FIG.

First, the configuration of the contact device 1 will be described first, and then the joining of the contact terminal and the bellows will be described.

The contact device 1 includes a container in which a fixed contact 2 and a movable contact 3, which are formed of tungsten and have a substantially disk shape, are housed. The fixed contact 2 and the movable contact 3 are arranged so as to make a line contact at their tops when they are brought into contact with each other. In this embodiment, the container is composed of a body 4, a lower plate 5, an upper plate 6 and a support cylinder 7. It goes without saying that each of these members is hermetically coupled. Body 2
Is formed of a ceramic such as alumina, and the lower plate 5 and the upper plate 6 are formed of, for example, an oxygen-free cylinder or a conductive metal material such as 42 alloy. Lower plate 5 and upper plate 6
Insulating members 10 and 22 are provided on the inner sides of the respective parts.

The fixed contact 2 is approximately V of the contact terminal 8 formed of an oxygen-free body or the like.
It is fixed to the open tip. The contact terminal 8 is fixed to the lower plate 5 by caulking. An electrically conductive ventilation pipe 9 used for sealing the mixed gas is attached to the lower plate 5. The fixed contact 2 includes a fixed terminal 8, a lower plate 5, and a ventilation pipe 9.
Are electrically connected to the outside through the three conductive members. In this embodiment, the ventilation pipe 9 is used as a conductive terminal.

The movable contact 3 is fixed to a substantially V-shaped tip (one side) of a contact terminal 21 made of oxygen-free copper. The rear end (other side) of the contact terminal 21 passes through the hole 22a and the hole 6a and goes out of the container. A bellows 23 hermetically seals between the support cylinder 7 which is a part of the container and the contact terminal 21. One end 23a of the bellows 23 is joined to the support cylinder 7, and the other end 23b is joined to the contact terminal 21. In this contact device 1, the other end 23b of the bellows 23 and the contact terminal 21 are joined together with high reliability to prevent the generation of cracks, as will be described later in detail. The contact terminal 21 is movable in a direction in which the movable contact 3 is brought into contact with and separated from the fixed contact 2. When the contact terminal 21 moves in the direction of arrow A, the movable contact 3 is pulled up and the contact is opened. . In the case of a relay or the like, the contact terminal 21 is configured to be moved by an electromagnet (not shown).

The mixed gas flows from the inside of the ventilation pipe 9 into the through hole 5a of the lower plate 5 and the insulating material 10.
It is introduced in a path reaching the sealed space 11 through the through hole 10a.
When the introduction of the mixed gas is completed, the ventilation pipe 9 is hermetically sealed. As the mixed gas, for example, a gas composed of hydrogen and nitrogen is used. In this case, it is desirable that the mixing ratio of nitrogen is adjusted within 20 to 97%.

In addition, the permanent magnet 24 arranged at the extension end 5b of the lower plate 5,
The magnetic force of 25 causes the arc generated at the time of contact opening to move downward from the tip of the fixed contact 2. Then, the arc voltage becomes high and the extinction of the arc is accelerated.

Subsequently, a process of joining the contact terminal 21 and the bellows 23 will be described.

The bellows 23 of this embodiment is made of Ni (nickel) -Cu (copper).
For example, a metal bellows made of a material having a three-layer structure of Ni and having a thickness of 30 μm and having a layer structure formed by electrodeposition is used. The thickness of the Ni layer is 12 to 14 μm. If the bellows 23 is made of only copper, the strength may not be sufficient, so that the Ni layer is provided. Au (gold) may be used, but it is not practical in terms of cost.

First, before welding, the contact terminal 2 shown in FIG.
The three parts of 1, the metal bellows 23, and the collar (color metal member) 24 are assembled as shown in FIG. 3 (b).

This assembling is done as follows, for example. The inner diameter of the cylindrical collar 24 is larger than the outer diameter of the contact portion 21a of the contact terminal. The collar 24 is fitted into the joint portion 21a so that one end 23b, which is the joint portion of the bellows 23, is in between, and then the collar 24 is caulked. That is, the metal bellows 23
The joint portion 23b is sandwiched between the contact terminal 21 and the collar 24, and the collar 24 is attached to the contact terminal 21. In this state, the portion of the metal bellows 23 pressed by the collar 24 is in close contact with the contact terminal 21 without any gap. Then, laser LS is irradiated from above the collar 24 to perform welding. When the welding is done from the top of the collar 24, the bellows 23 does not evaporate and scatter at that location because the collar 24 is above it. Moreover, since there is no gap between the contact terminal 21 and the bellows 23, the occurrence of cracks can be suppressed in this respect as well.

The collar 24 is preferably made of Ni or a Ni alloy, which is made of Ni (nickel). One of the contact terminals 21 is usually made of Cu (copper) -based material.
This is because it is difficult to properly perform welding when the materials of 24 are not Ni-based.

For example, if the material of color 24 is Fe (iron),
Although Fe and Cu (copper) of the Cu-based contact terminal 21 are melted, cracks are easily generated in the weld nugget portion. As shown in Fig. 4, the molten alloy of Cu and Fe has a wide solidification temperature range, and the strain of the solidified portion at the beginning is added to the non-solidified portion, which causes cracks in the weld nugget and causes the damage to the joint. Become. 4 is an equilibrium diagram of Cu and Fe,
In the figure, AB is the liquidus line and AC is the solidus line.

On the other hand, when the collar 24 is made of Ni-based material, this Ni
And Cu (copper) of the Cu-based contact terminal 21 will melt,
It is difficult for cracks to occur in the weld nugget. As shown in FIG. 5, the molten alloy of Cu and Ni has a narrow solidification temperature range, and thus the occurrence of cracks in the weld nugget portion as described above can be suppressed. In addition, FIG. 5 is an equilibrium diagram of Cu and Ni. In the figure, A′-BC ′ is a liquidus line,
A'-D-C 'is the solidus line.

The collar 24 is preferably annealed before being applied to the contact terminals 21. When annealed, the elongation of collar 24 is 15-35%
The reason is that the strain increases to 35 to 55% and the strain during welding is more easily absorbed. The annealing is performed, for example, by heat treatment in vacuum at a temperature of 800 ° C. for 60 minutes.

The present invention is not limited to the above embodiment. The method of attaching the collar to the contact terminal may be a method other than crimping.
Welding methods other than laser welding may also be used. It goes without saying that the contact device is not limited to the illustrated structure.

〔The invention's effect〕

As described above, the manufacturing method of the contact device according to the present invention can suppress damage not only in the manufacturing process but also in the place where the bellows and the contact terminal are joined after the manufacturing process. Therefore, the manufacturing yield is improved, the sealed state is maintained for a long period of time, the contact is consumed less, and the contact life is extended.

[Brief description of drawings]

FIG. 1 is a sectional view of a contact device manufactured by an embodiment of the manufacturing method according to the present invention, and FIG. 2 is a sectional view II of FIG.
-II is a cross-sectional view, FIG. 3 is a schematic explanatory view showing how the bellows and the contact terminal are welded, and FIG. 4 is Cu.
Fig. 5 is an equilibrium diagram of Fe, and Fig. 5 is an equilibrium diagram of Cu and Ni. 1 ... Contact device, 2 ... Fixed contact, 3 ... Movable contact, 21 ... Contact terminal, 23 ... Bellows, 24 ... Color

Claims (3)

[Claims] 1. A fixed contact and a movable contact are housed in a container, and a contact terminal having the movable contact on one side and being exposed to the outside on the other side moves in a direction to separate and contact the movable contact from the fixed contact. It is provided so as to be able to perform contact separation / contact operation by the movement of the contact terminal, and a metal bellows that hermetically seals the space between the container and the contact terminal is joined to the contact terminal by welding. Along with obtaining a sealed contact device in which a mixed gas containing hydrogen is sealed in the container, a collar-shaped metal member is adhered to the contact terminal so that the metal bellows is sandwiched therebetween,
A method for manufacturing a sealed contact device, wherein the welding is performed on the metal member. 2. The method for manufacturing a sealed contact device according to claim 1, wherein the collar-shaped metal member is annealed. 3. The method for manufacturing a hermetically sealed contact device according to claim 1, wherein the collar-shaped metal member is made of a Ni-based material and the contact terminals are made of a Cu-based material.