JPS604534B2 - vacuum valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum valve, and more particularly to a vacuum valve whose conductive terminals are silver-plated.

Generally, a vacuum valve is constructed by having a pair of separable electrodes within the vacuum container configured as an insulating container and end plates attached to both ends of the vacuum container.

A current-carrying shaft is led out from the pair of electrodes in a vacuum-tight manner to form a haze path. A portion of the current-carrying shaft led out to the outside is used as a current-carrying terminal for connecting an external conductor. This current-carrying terminal may or may not be silver-plated. When the current carrying capacity is large, loose fitting allows for a higher temperature rise limit than without silver plating, so the current carrying terminals of vacuum valves are often silver plated. . The following two methods have been conventionally used as methods for silver plating current-carrying terminals. m A method in which the current-carrying shaft of the part that becomes the current-carrying terminal is silver-plated during the vacuum valve component stage.

[21 Method of applying silver plating to the current-carrying terminal after completing the vacuum valve.

Both methods have the following problems at the stage of applying the money, making the vacuum valve expensive and impairing its quality.

In other words, method m above is a method in which silver plating is applied to the current-carrying terminal portion of the current-carrying shaft at the component stage, so in that case, silver plating should not be applied to areas other than the current-carrying terminal portion during the silver plating process. There must be. To explain this silver plating process, ■Electrical shaft processing→■Taping of areas not to be silver plated→■Masking agent (paint) on taped areas
There are roughly 6 steps: applying → ■ silver plating → ■ peeling off the masking area → ■ peeling off the masking area and brushing the areas where peeling is insufficient. In addition, method {2- above is a method in which silver plating is applied to the current-carrying terminal portion after the vacuum valve is completed, and in that case, the silver-plated portion of the current-carrying terminal is immersed in a plating solution and plating is performed as required. Because of this, there is a high risk that the plating solution, which is made up of strong acids, will adhere to and remain in areas other than the mating areas, and corrosion caused by this has become a problem.

In particular, when silver plating is applied to the part of the movable current-carrying shaft that becomes the current-carrying terminal, a thickness of only 0.1 to 0.2 mm is applied near the movable current-carrying shaft to enable the pair of electrodes to be separated. A metal bellows formed in the shape of a thin bellows is provided, and if plating liquid remains on this metal bellows portion, it will be easily attacked by strong acids. As a result, there was a problem in that leakage occurred from the metal bellows due to corrosion, reducing the vacuum of the vacuum valve. Therefore, this was not a sufficient plating method for vacuum valves that require high reliability.
The present invention has been made in view of this point, and it is an object of the present invention to provide an inexpensive and high-quality vacuum valve by configuring the current-carrying terminal and the current-carrying shaft as separate parts.

Embodiments of the present invention will be described below with reference to the drawings.

In the figure, 1 is an insulating container, with both ends connected to end plates 2a and 2.
A pair of electrodes 4a facing each other in the vacuum container 3 closed by
, 4b are internally connected, and current-carrying shafts 5a, 5b are connected to both end plates 2a, 2 in a vacuum-tight manner from the pair of electrodes 4a, 4b, respectively.
It is led out to the outside of b to form a military route. A metal bellows 6 is provided between the movable current-carrying shaft 4b and the movable end plate 2b in order to enable the pair of electrodes 4a and 4b to be separated in a vacuum-maintained state.

Reference numeral 7 denotes an arc shield for preventing staining of the inner wall of the insulating container 1 from high-temperature metal vapor generated between the electrodes during mist flow or interruption.

8a is a fixed-side current-carrying terminal provided at the end of the fixed-side current-carrying shaft 5a;
Reference numeral 8b denotes a movable-side current-carrying terminal provided at the end of the movable-side current-carrying shaft 5b, and the entire surface of each of the current-carrying terminals 8a, 8b is silver-plated in advance as indicated by the dotted line in the figure.
That is, the current-carrying terminals, which have been silver-plated in advance, are fixed to the ends of the current-carrying shafts 5a and 5b extending outside by means such as silver soldering during the assembly stage of the vacuum valve.

According to the above configuration, since the current-carrying shafts 5a, 5b and the current-carrying terminals 8a, 8b are constructed as separate parts, it is only necessary to apply silver plating to the current-carrying terminals 8a, 8b.
Since it is a method of applying silver plating to the entire surface of a and 8b,
The troublesome masking work that caused problems with the prior art becomes unnecessary.

Therefore, silver plating can be carried out continuously and in large quantities with high efficiency, and there are other effects such as reducing the size of the entire part to be silver plated and making it easier to transport the parts. 0, which is advantageous for economical production. Furthermore, the silver plating on the current-carrying terminals 8a and 8b is a method in which silver plating is applied to the entire surface of each single unit in advance, and masking is not required, so the removal of the masking agent is incomplete and the quality of the vacuum valve is affected. There is no need to worry about deterioration. As shown in the example by Sayu et al., the method of partially silvering the current-carrying shaft after completing the vacuum valve is a method that can cause leaks due to corrosion if the plating solution, which is made of a strong acid, adheres to the metal bellows. However, these problems can be solved, and there are various effects in improving the quality of the vacuum valve. The overall evaluation of the present invention is as shown in Table 1 when compared with the prior art. Table 1 Comprehensive evaluation [Comparison when ko is set to 100 * Estimated based on silver plating ability (varies depending on the size of the current-carrying terminal)
.

※※ Masking and brushing are manual and more expensive than the present invention. ※※※ When brushing, the metal from the energizing shaft adheres to the current-carrying shaft, and the strength of the twill brazing, etc., becomes unstable. It is prone to scratches, has a high rate of assembly defects, and has problems with quality stability.

As described above, according to the present invention, the current-carrying terminal and the current-carrying shaft are constructed as separate parts, the entire surface of the current-carrying terminal is metal-plated in advance, and then the current-carrying terminal is assembled in the vacuum valve assembly stage. This structure simplifies the plating process and eliminates the problem of the plating liquid adhering to the metal bellows and causing corrosion, making it possible to create an inexpensive, high-quality vacuum valve. Can be provided.

[Brief explanation of the drawing]

The figure is a sectional view showing one embodiment of the present invention. 1... Insulating container, 2a, 2b... End plate, 3... Vacuum container, 4a, 4b... Electrode, 5a, 6b... ...Electricity shaft, 6...Metal bellows, 7...Arc shield, 8a...
Fixed side energizing terminal, 8b...Movable side energizing terminal.

Claims (1)

[Scope of Claims] 1. An insulating container, and a pair of separable electrodes arranged in a vacuum container with both ends of the insulating container closed with end plates, and electricity supplied to the outside from the pair of electrodes in a vacuum-tight manner. A vacuum valve characterized in that a current-carrying terminal member is provided with a shaft, and at least the end portion of the movable current-carrying shaft led out to the outside is silver-plated, and is fixed with silver brazing. 2. The vacuum valve according to claim 1, wherein current-carrying terminal members are fixed to the ends of the current-carrying shafts on both the fixed side and the movable side by silver brazing.