JP2018055928A - Contact material for vacuum valve, manufacturing method, and vacuum valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain good cutoff performance and excellent withstand voltage performance in a metal of a melting system, and improve welding resistance characteristics.SOLUTION: A vacuum valve according to an embodiment, comprises: a cylindrical ceramic vacuum insulation container; a fixed side sealing metal fitting that is sealed to one end opening part of the vacuum insulation container; a fixed electrode shaft that is penetrated and fixed to the fixed side sealing metal fitting; a fixed contact point that is fixed to the fixed electrode shaft; a movable sealing metal fitting that is sealed to the other opening part of the vacuum insulation container; a movable electrode axis that movably penetrates to the movable sealing metal fitting; a movable contact point that is fixed to the movable electrode axis, and contact and separate to/from the fixed contact point; a freely extendable bellows of which one end is sealed to a middle part of the movable electrode axis, and the other end is sealed to the movable sealing meal fitting; and an arc shield that is sealed in a middle grove part of the vacuum insulation container, and surrounds the fixed contact point and the movable contact point. The fixed contact point and the movable contact point are formed by Cu-Cr-Te alloy including dendrite Cr and Te of a predetermined ratio as an additive material.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a contact material for a vacuum valve, a manufacturing method, and a vacuum valve.

  The characteristics required for the vacuum valve include the three basic requirements of breaking performance, withstand voltage performance, and welding resistance. For this reason, contact materials for vacuum valves that have all these characteristics are required. However, because these characteristics have conflicting properties, it is difficult to satisfy all the characteristics with a single metal species. is there.

  For this reason, contact materials for vacuum valves that have been put to practical use are composed of a combination of two or more elements, such as a conductive component and an arc-proof component, that can mutually compensate for the lack of characteristics, It is used according to the desired application such as for use.

  In recent years, among various types of contact materials for vacuum valves, those having characteristics satisfying the breaking performance and withstand voltage performance include, for example, Cu as a conductive component and arc resistance as described in Patent Document 1. A contact material for a Cu—Cr based vacuum valve containing Cr as a component is known.

  On the other hand, there are known contact materials for Cu-Bi and Cu-Te based vacuum valves containing an anti-welding component such as Bi or Te for the purpose of improving welding resistance (for example, Patent Document 2 or Patent). Reference 3).

JP 54-71375 A Japanese Patent Publication No.41-12131 Japanese Patent Publication No. 44-23751

By the way, the contact material for the Cu-Cr-based vacuum valve is excellent in the breaking performance, and further, the improvement of the withstand voltage performance can be expected by the melting method rather than the sintering method. There was a problem of being low.
On the other hand, the contact materials for Cu-Te and Cu-Bi vacuum valves having excellent welding resistance have a problem that the re-ignition occurrence probability is high and the withstand voltage performance is low.

  Accordingly, an object of the present invention is to provide a contact material for a vacuum valve and a vacuum valve capable of improving the welding resistance while maintaining good breaking performance and excellent withstand voltage performance of a molten metal. Yes.

  The contact material for a vacuum valve of the embodiment is made of a Cu—Cr—Te alloy containing dendritic Cr and a predetermined ratio of Te as additives in a Cu matrix.

FIG. 1 is a partial cross-sectional view of a vacuum valve according to an embodiment. FIG. 2 is an explanatory diagram of the relationship between the Te content and the welding force ratio. FIG. 3 is an explanatory diagram of the relationship between the Te content and the blocking performance ratio. FIG. 4 is a manufacturing flowchart of a Cu—Cr—Te alloy. FIG. 5 is a cross-sectional photomicrograph for comparing the Cu—Cr—Te alloy by the embodiment and the conventional sintering method. FIG. 6 is an explanatory diagram of element distribution analysis using a scanning electron microscope (SEM).

Hereinafter, embodiments will be described in detail with reference to the drawings.
FIG. 1 is a partial cross-sectional view of a vacuum valve according to an embodiment.
The vacuum valve 10 is sealed with a ceramic vacuum insulating container 11 having a cylindrical shape, and an opening 13A inserted in a state in which the fixed electrode shaft 12 is fitted into the opening 11A at one end of the vacuum insulating container 11. A movable member provided with an opening 15A in which the movable electrode shaft 14 is slidably fitted and sealed in the provided disc-shaped fixed-side sealing fitting 13 and the opening 11B at the other end of the vacuum insulating container 11. The side sealing fitting 15, the fixed-side contact member 16 vacuum-brazed to the tip of the fixed electrode shaft 12 in the vacuum insulating container 11, and the vacuum-brazed to the tip of the movable electrode shaft 14 in the vacuum insulating container 11 The movable contact member 17, the fixed contact member 16 and the movable contact member 17 are arranged around the metal particles evaporated from the fixed contact member 16 or the movable contact member 17 and deposited on the inner surface of the vacuum insulating container 11. of The arc shield 18 for preventing, the intermediate part 14M of the movable electrode shaft 14 and the movable side sealing metal fitting 15 are sealed to cover the opening 15A, and can be expanded and contracted to maintain the vacuum in the vacuum insulating container 11. And a metal bellows 19 for the purpose.

  In the above configuration, the fixed-side contact member 16 and the movable-side contact member 17 have a disk shape, and are spirally shaped so as to gradually approach the central axis from the outer peripheral surfaces of the fixed-side contact member 16 and the movable-side contact member 17 ( A plurality of (for example, three) slits SS formed in a spiral shape are provided. According to the spiral slit SS, a radial magnetic field (transverse magnetic field) can be generated, and the local contact material can be prevented from melting and the interruption performance can be ensured and improved.

More specifically, a radial magnetic field is applied to the arc generated between the fixed contact member 16 and the movable contact member 17, and the arc is caused by the Lorentz force generated between the magnetic field and the arc current. By rotationally driving in the circumferential direction, local melting of the stationary contact member 16 or the movable contact member 17 can be prevented, and a desired breaking performance can be obtained.
Moreover, in the vacuum valve 10, the pressure in the vacuum insulating container 11 is, for example, 10 ⁻⁴ Pa or less.

Here, the material for forming the stationary contact member 16 and the movable contact member 17 will be described.
The fixed-side contact member 16 and the movable-side contact member 17 are made of a Cu—Cr—Te alloy containing copper (Cu) as a base material and containing chromium (Cr) and tellurium (Te).
In this Cu—Cr—Te alloy, the content ratio of the raw material metal is a weight ratio (% by weight): Cu: Cr: Te = x: y: z (x> y >>z> 0, x + y + z = 100)
It is said that.
Here, the range of Te content is 0.03 ≦ z ≦ 0.5 (wt%). The reason why the Te content range is set to this range will be described below.

FIG. 2 is an explanatory diagram of the relationship between the Te content and the welding force ratio.
Here, the welding force ratio is a ratio of welding force with reference to the welding force in a state containing no Te at all (= 1), and represents a state in which welding does not occur as the value is lower.

According to FIG. 2, it can be seen that if the Te content is 0.03 (% by weight) or more, the welding force is sufficiently low.
As a result, welding removal can be easily performed even with a weak operating force.

FIG. 3 is an explanatory diagram of the relationship between the Te content and the blocking performance ratio.
Here, the interruption performance ratio is a ratio of the interruption performance based on the interruption performance in a state containing no Te at all (= 1), and the higher the value, the more the interruption performance is maintained. .
According to FIG. 3, it can be seen that when the Te content is 0.5 (% by weight) or less, the blocking performance is sufficiently maintained (the blocking performance ratio is 0.9 or more).

Next, an outline of a method for producing a Cu—Cr—Te alloy will be described.
FIG. 4 is a manufacturing flowchart of a Cu—Cr—Te alloy.
First, Cu (copper), Cr (chromium), and Te (tellurium) are weighed so as to be a predetermined weight% (= predetermined ratio) (step S11).

Next, the weighed copper, chromium and tellurium are put into a crucible (crucible) and completely dissolved in a vacuum atmosphere (vacuum atmosphere furnace) (step S12).
Subsequently, it is rapidly cooled and solidified (step S13).

FIG. 5 is a cross-sectional photomicrograph for comparing the Cu—Cr—Te alloy by the embodiment and the conventional sintering method.
As shown in FIG. 5A, in the Cu—Cr—Te alloy manufactured by the melting method of the present embodiment, the temperature is raised to a temperature at which Cr is dissolved. It is precipitated as dendritic crystals).

  On the other hand, as shown in FIG. 5 (b), in the conventional sintering method, it is put in a mold at a temperature at which Cu does not dissolve (the melting point of Cu is 1084.6 ° C., for example, 700 ° C. to 1080 ° C.). Press to mold. For this reason, since the sintering is performed at a temperature at which Cr (melting point: 1903 ° C.) does not dissolve, in the Cu—Cr—Te alloy, Cr is in a state of being dispersed in a particle state.

Therefore, the Cu—Cr—Te alloy of this embodiment is in a more homogeneous state in which each component is uniformly distributed than the Cu—Cr—Te alloy obtained by the conventional sintering method.
Thereby, the electrode of the stable quality can be comprised.

FIG. 6 is an explanatory diagram of element distribution analysis using a scanning electron microscope (SEM).
By the way, since it is difficult to identify and identify Te added in a small amount in an optical micrograph, as shown in FIG. 6, element distribution analysis using SEM was performed to identify and identify Te.

FIG. 6A is a normal SEM image, which is an image of a portion where dendritic Cr is distributed in the Cu matrix and a small amount of Te is distributed in the Cu matrix. It is not easy to determine whether Te is distributed from only this SEM image.
Therefore, as shown in FIGS. 6B to 6D, the distribution of each atom is grasped using characteristic X-rays (fluorescence X-rays).

  More specifically, as shown in FIG. 6B, the distribution of Cu is grasped using a K line (Cu K line) that is a characteristic X ray of Cu. In FIG. 6B, the blacker portion indicates that the distribution of Cu is large.

  Similarly, as shown in FIG. 6C, the distribution of Cr is grasped using the K line (Cr K line) which is a characteristic X-ray of Cr. In FIG.6 (c), the blacker part has shown that there is much distribution of Cr.

  Further, as shown in FIG. 6D, the Te distribution is grasped by using an L line (Te L line) which is a characteristic X ray of Te. In FIG. 6D, it can be seen that Te is distributed in the portion indicated by the black dots.

  As a result, as shown in FIG. 6A, it can be seen that dendritic Cr is distributed in the Cu matrix, and a small amount of Te is distributed in the Cu matrix.

  In the above description, a configuration in which a transverse magnetic field is generated by a spiral slit is adopted. However, a configuration in which a longitudinal magnetic field electrode that generates a longitudinal magnetic field is used depending on a voltage system to be applied and an assumed breaking capacity is used. Is also possible. Even in this case, the interruption performance can be improved by generating a magnetic field that diffuses the arc.

  Moreover, in the above description, the case where the spiral electrode as the transverse magnetic field electrode is used as the fixed side contact member 16 and the movable side contact member 17 has been described, but the control electrode classified into the same transverse magnetic field electrode, The present invention can be similarly applied by using a vertical magnetic field electrode such as a cup-type vertical magnetic field electrode.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Vacuum valve 11 Vacuum insulating container 11A Opening part 11B Opening part 12 Fixed electrode shaft 13 Fixed side sealing metal fitting 13A Opening 14 Movable electrode axis 14M Middle part 15 Movable side sealing metal fitting 15A Opening 16 Fixed side contact member 17 Movable side contact member 18 Arc shield 19 Bellows SS Slit

Claims (8)

It consists of a Cu-Cr-Te alloy containing dendritic Cr and a predetermined ratio of Te as additives in a Cu matrix.
Contact material for vacuum valves. The predetermined ratio is 0.03 to 0.5% by weight,
The contact material for a vacuum valve according to claim 1. A process of weighing powdered Cu, Cr and Te so as to have a predetermined ratio,
A process of putting the weighed Cu, Cr and Te into a crucible and melting in a vacuum atmosphere to form a molten metal;
A process of rapidly cooling and solidifying the molten metal to form a contact having a predetermined shape;
A manufacturing method comprising: Forming the contact by repeating the process of rapidly cooling the molten metal and the solidifying process a plurality of times;
The manufacturing method of Claim 3. A cylindrical vacuum insulating container made of ceramics;
A fixed-side sealing fitting sealed at one end opening of the vacuum insulating container;
A fixed electrode shaft penetrating and fixed to the fixed-side sealing metal fitting,
A stationary contact fixed to the stationary electrode shaft;
A movable side sealing fitting sealed to the other opening of the vacuum insulating container;
A movable electrode shaft that movably penetrates the movable side sealing fitting;
A movable contact fixed to the movable electrode shaft and contacting and leaving the fixed contact;
A telescopic bellows having one end sealed to the middle portion of the movable electrode shaft and the other end sealed to the movable-side sealing metal fitting,
An arc shield that is sealed at an intermediate groove of the vacuum insulating container and surrounds the fixed contact and the movable contact;
The fixed-side contact and the movable-side contact are formed of a Cu-Cr-Te alloy containing dendritic Cr and a predetermined ratio of Te as additives in a Cu matrix.
Vacuum valve. The fixed side contact and the movable side contact have a disk shape, and are configured as a transverse magnetic field electrode or a longitudinal magnetic field electrode,
The vacuum valve according to claim 5. The fixed-side contact and the movable-side contact are configured as a spiral-shaped spiral electrode or a control electrode as the transverse magnetic field electrode,
The vacuum valve according to claim 6. The fixed contact and the movable contact are configured as a cup-type longitudinal magnetic field electrode as the longitudinal magnetic field electrode,
The vacuum valve according to claim 6.