JPS59169012A - Contact material for vacuum breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a contact material for a vacuum breaker that has excellent withstand voltage characteristics and high current interrupting performance.

Satisfactory characteristics of contact material for vacuum breaker include (1
) have large breaking capacity, (2) have high withstand voltage,
(3) Low contact resistance, (4) Low welding force, (5) Low contact wear, (6) Low cutting current value, (7) Good workability, (8) ) have sufficient mechanical strength, etc.

Conventionally, copper-bismuth (hereinafter Cu) has been used as this type of contact material.
-Display as B i. Alloys made of other elements and combinations of elements are similarly indicated by element symbols. )
, Cu-Cr-B1, Cu-Co-Bi, C
u-Cr etc. were used. However, in the case of an alloy contact containing a low melting point gold tip such as Cu-81, a part of the metal diffuses and evaporates from within the contact due to high temperature heating during the evacuation process, and adheres to the metal shield or insulating container in the vacuum container.

This is one of the major factors that degrades the withstand voltage of vacuum breakers. Furthermore, when switching loads or cutting off large currents, low melting point metals evaporate and scatter, resulting in deterioration of withstand voltage and deterioration of cutoff performance.

Cr has excellent vacuum withstand voltage to eliminate the above drawbacks.

Even with Cu-Cr-Bi added with Co etc., the above-mentioned drawbacks due to low melting point metals are not fundamentally solved,
Cannot handle high voltage and large current. On the other hand, Cu-Cr
Gold pA (Cr, C) has excellent vacuum withstand voltage, such as gold pA (Cr, C).

) and Cu, which has excellent electrical conductivity, is slightly inferior in terms of welding resistance compared to contact materials containing low melting point metals, but has superior breaking performance and withstand voltage performance. , often used in high voltage and large current ranges. Furthermore, since there is a limit to the breaking performance of Cu-Cr alloys, by devising the shape of the contact and manipulating the current path of the contact, a magnetic field is generated, and this force can be used to generate a large current arc. Efforts were being made to improve the breaking performance by force driving.

Furthermore, in Japanese Patent Publication No. 56-40457, Cu-Be
- High vapor pressure low melting point materials (Bi, Te,
Vacuum contact materials to which Se, etc.) are added have been proposed. However, the AI addition range of this contact material is 4 to 9% by weight.
According to our experiments, in the range of 0.1 to 10% by weight, the contact resistance increases, and when the low melting point material is added in the range of 0.1 to 10% by weight, phenomena such as a decrease in mechanical strength are observed.

However, in recent years, as the voltage and current of vacuum breakers have increased, it has become difficult to satisfy the new requirements with the conventional contact materials.

This invention was made to eliminate the drawbacks of the conventional products as described above, and an object of the present invention is to provide a contact material for a vacuum breaker that has excellent large current interrupting performance and high withstand voltage performance.

We fabricated a material consisting primarily of Cu with the addition of various metals using a vacuum melting method, incorporated it into a vacuum switch tube, and extensively investigated its various properties.

This release 8A contains Cu, Be O, 5 to 3.5% by weight,
and 3.5% by weight or less of Al, and 2.5% by weight or less of at least one of Ti and Zr.

Figure 1 is a sectional view of a vacuum switch tube, showing (1) a vacuum insulating container, and end plates (2) closing both ends of the vacuum insulating container (1).
) and (3).
) and (5) are arranged at one end of the electrode rods (6) and (7), respectively, so as to face each other. The electrode rod (7) is joined to the end plate (3) via a bellows (8) so as to be movable in the axial direction without compromising airtightness. The shields (9) and (10) cover the inner surface of the vacuum insulating container (1) and the bellows (8), respectively, to prevent contamination with vapor generated by the arc. The structure of contacts (4) and (5) is shown in FIG. The contact (5) is brazed to the electric wire (7) with a brazing material (11) interposed on its back side. The contacts (4) and (5) are -, -Be -AI - of the present invention.
(Ti, Zr) system contact material.

The results of various measurements or tests will be explained below.

In addition, in Figures 3 and 4 and the table, the currently used C
It is shown as a comparative value with a contact material of u=25% by weight Cr alloy.

Figure 3 shows the relationship between the amount of Al added to the alloy with the amount of Be fixed at 1% by weight and the amount of Ti fixed at 1% by weight and the amount of shear. It can be seen that the breaking performance is improved compared to the current product (Cu-25% by weight Cr alloy) within the range of % by weight or less.

As for the amount of AI added, the existence of an optimal composition is seen in the range of 1 to 2% by weight, and if it is added more than 3.5% by weight,
There is a tendency for the breaking capacity to decrease.

As shown in the table below, the cause of this seems to be related to the decrease in the conductivity of the contact material.

Figure 4, like that shown in Figure 3, shows the relationship between the amount of Al added and the withstand voltage when the amount of Be and Ti are fixed, and the amount of Al is 0.5% by weight or more. A considerable effect was seen in the results, and no significant difference was observed in the withstand voltage characteristics even when the amount of AI added was increased.

The table shows the additive amount and conductivity (IAC5: International An
An example of measuring the Vickers hardness (nealed copper 5 standard) and 19 overweight Vickers hardness (Hv) is shown.

According to this, except for the lack of electrical conductivity in the sample with an All content of 5%, the other prototypes have no particularly disadvantageous characteristics in practical use, but the electrical conductivity is lower than that of the Cu-25 wt% Cr alloy. is low and Vickers hardness is high.

Next, the effect of adding the alloy components forming the contact material of the present invention and the limitations on the amount added will be explained.

(Ma) Regarding Be addition, (Ma) C forming IJ lux.
The hardness can be increased without significantly reducing the conductivity of the u-alloy.
The effect of improving voltage resistance is well known, but in experiments conducted by the inventors, no effect on voltage resistance or shielding property was observed with BeO of 5% by weight or less; on the other hand, due to processability and pollution problems Since it is not preferable to add a large amount of Be, the amount of Be added is limited to 0.5 to 3.5% by weight.

Next, regarding A1 addition, the hardness of the Cu-Be alloy contact,
Although it is known that it improves withstand voltage, adding a fourth element has a remarkable effect of improving properties, especially in a range where the AI content is low, and conversely, when the AI content exceeds 3.5% by weight, the electrical conductivity tends to decrease. This is not preferable as a contact material, as the breaking capacity decreases. Therefore, the amount of AI added is limited to 3.5% by weight or less.

Furthermore, the addition of Ti, Zr or Ti + Zr
-By suppressing the coarsening of the crystal grains of the entire -Be-Al alloy and refining the structure, it is effective to improve the hardness and withstand voltage even in a low addition range of Be or AI. However, if the total amount of Ti and Zr added exceeds 2.5%, there are problems with workability, breaking performance, etc. Therefore, the amount of Ti1 or Zr, or the total amount of the two added, is limited to 2.5% by weight or less.

In addition, Bi, Te, 5e1Sb, Mg are added to the above alloy.
, and at least one of Pb low melting point materials.
When added in weight percent or less, significant improvements in welding resistance and shielding properties are observed without increasing the dielectric strength and shielding properties of the Cu-Be-A I alloy system, resulting in high withstand voltage and large current shielding properties. It was confirmed that a contact material with excellent welding and cutting properties as well as good welding and cutting properties could be obtained. However, if the amount of the low melting point material added increases, embrittlement phenomenon due to a decrease in mechanical strength is observed, which is undesirable. Therefore, the addition of the low melting point material is limited to a range of 8% by weight or less.

As described above, according to the present invention, Cu, Be O,
5 to 3.5% by weight, and 3.5% by weight or less of AI, and 2.5% by weight or less of at least one of Ti and Zr. This has the effect of providing a highly reliable contact material for a vacuum breaker that has breaking capacity and voltage resistance, and also has other physical properties.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the structure of a vacuum switch tube to which an embodiment of the present invention is applied, Fig. 2 is an enlarged view of the contact portion of Fig. 1, and Fig. 3 is the amount of Be in the contact material of the present invention. Figure 4 is a characteristic diagram showing the change in breaking capacity when the amount of AI added is changed for an alloy in which the amount of Be is fixed at 1% and the amount of Ti is fixed at 1%. ni, T
FIG. 2 is a characteristic diagram showing the change in voltage resistance performance when the amount of AI added is changed for an alloy in which the amount of i is fixed at 1%. (1)...Vacuum insulation container, (2), (3)...End plate, (4L (s)...Contact, (6), (7)...
・Electrode rod, (8)...Bellows, (9), (10)
... (9) Shield, (51) ... Brazing material (10) Fig. 1 Fig. 2 Fig. 3 AI style Iu simulation%)

Claims (2)

[Claims] (1) It is characterized by containing Cu, BeO, 5 to 3.5% by weight, and 1.5% by weight or less of Al, and 2.5% by weight or less of at least one of Ti and Zr. Contact material for vacuum breaker. (2) The contact material for a vacuum breaker according to claim 1, which contains at least 8% by weight of at least one of Bi, Te, Se, Sb, Mg, and Pb.