JPH10199381A - Circuit breaker and manufacture of vacuum bulb used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fill a fine air gap of a tightening part, increase a contact area, reduce an electric and thermal contact resistance, restrain heat generation, and improve thermal conductivity by applying a solvent having a specific conductivity on a bonding face of a main circuit current conducting member tightening part, tightening with a specific hardness or less, and drying, and hardening. SOLUTION: A clamp 6 connected to a flexible conductor 7 is dried and hardened after a solvent 9 having a conductivity below 10<-3> Ωm or less in resistance is applied and hardness of the solvent 9 is 40Hv or less in the status of which the clamp is tightened to a movable contact conductive shaft 18 with bolts. Thereby, the hardened solvent 9 is filled in a gap at a screw contact part of both parties. In addition, this is performed similarly at a tightening part between a fixed contact conductive shaft and a conductive conductor. A conductive thin film of 50 micrometers or less in thickness and 40Hv or less in hardness may be employed in place of the solvent 9, and the main component of this thin film and the coating 9 is preferably Ag. Preferably, a movable contact conductive shaft 18 or the like is made of a copper material, and the coating 9 is made of a silver filler and a synthetic resin binder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a circuit breaker and a method for manufacturing a vacuum valve used for the circuit breaker.

[0002]

2. Description of the Related Art Although there are many types of circuit breakers, a vacuum circuit breaker shown in FIG. 4 will be described as an example. FIG. 1 shows a side sectional view of a typical vacuum circuit breaker. In FIG. 1, a vacuum circuit breaker of this type includes a frame 1 serving as a ground metal.
And an insulating barrier 3 supporting the vacuum valve 10 and a frame 1 connected to a movable contact energizing shaft 18 of the vacuum valve 10.
And an insulated operation rod 4 for transmitting an operation force of an operation mechanism (not shown) provided in the inside of the device. The conducting conductor 5 is fastened to the fixed contact conducting shaft 17 of the vacuum valve 10 with a bolt. A clamp 6 is fastened to a movable contact energizing shaft 18 of the vacuum valve 10 by a bolt, and a flexible conductor 7 is fastened to the clamp 6 and an energizing conductor 8 is fastened to the flexible conductor 7 by a bolt. A slide contact may be electrically connected to the clamp 6 instead of the flexible conductor 7. FIG. 5 is an enlarged sectional view of a portion C in FIG. A male screw is formed on the movable contact energizing shaft 18, and a female screw is formed on the clamp 6.
And an integrated operation.

[0003] During energization, the portion of the vacuum valve 10 where the fixed contact and the movable contact come into contact generates the largest amount of heat and the temperature also increases. Since there is no convection in the vacuum valve 10 due to the vacuum, most of the heat is radiated by conduction from the fixed contact conducting shaft 17 through the conducting conductor 5 and the movable contact conducting shaft 18 through the conducting conductor 8.

However, the movable contact energizing shaft 18 and the clamp 6
Since the screw contact area of the screw is a meshing part of the screw, the entire surface does not contact and there is a small air gap, the contact area is small, the temperature rises due to the heat generated by the contact electric resistance, and the contact In some cases, thermal resistance was large and sufficient heat conduction was not performed.

Next, an example of the vacuum valve 10 used in the above-described vacuum circuit breaker will be described with reference to FIG. In the figure, reference numeral 11 denotes a cylindrical insulating cylinder made of an insulating material such as glass or ceramics, and the openings at both ends thereof are closed by a fixed-side metal end plate 12 and a movable-side metal end plate 13, respectively. Is formed. Fixed side metal end plate 1
A fixed contact energizing shaft 17 is penetrated and fixed to 2, and a movable contact energizing shaft 18 is movably penetrated through a bearing 21 through the movable side metal end plate 13 so as to face the fixed contact energizing shaft 17. A fixed contact (fixed electrode) 15 is attached to the fixed contact energizing shaft 17 in the facing portion, and the movable contact energizing shaft 18
A movable contact (movable electrode) 16 is attached to the movable contact. The following silver plating is applied to the fixed contact energizing shaft 17 and the movable contact energizing shaft 18 in order to obtain good conductivity. That is, the fixed contact energizing shaft 17 and the movable contact energizing shaft 18
Is silver-plated on oxygen-free copper, and a plating layer is formed by oxygen-free copper-thin nickel plating-thin copper plating-thin silver plating-silver plating. A metal bellows is provided between the movable metal end plate 13 and the movable contact energizing shaft 18 so as to keep the inside of the vacuum vessel 14 airtight and allow the movable contact energizing shaft 8 to move in the axial direction. 19 are provided. Reference numeral 20 denotes a shield, which is provided so as to surround the fixed contact 15 and the movable contact 16. In the mounting structure of each member as described above, each energized shaft 17, 18 and its corresponding fixed contact 15 and movable contact 16, fixed side metal end plate 12, and fixed contact energized shaft 1
7, movable contact energizing shaft 18 and one end of bellows 19, movable metal end plate 13 and the other end of bellows 19, and each metal end plate 1
The joint portions of the insulating tubes 11 and 2 are joined by brazing or welding.

The movable contact energizing shaft 18 is axially driven by an operating mechanism (not shown), so that the fixed contact 15
The movable contact 16 is brought into and away from the movable contact 16.

[0007]

In the conventional circuit breaker, since the screw contact portion between the movable contact energizing shaft 18 and the clamp 6 is a screw engagement portion, the entire surface does not come into contact with the small circuit breaker. In some cases, there was a medium gap, the contact area was small, the temperature increased due to the heat generated by the contact electric resistance, and the contact heat resistance was large and sufficient heat conduction was not performed. Therefore, in the conventional circuit breaker, when the energizing current is increased, the temperature increase value of the movable contact energizing shaft 18 increases, and the energizing capacity of the circuit breaker is determined by the temperature increase limit. It is necessary to take measures such as making the movable contact energizing shaft 18 thicker.

Further, in the conventional vacuum valve 10, the fixed contact energizing shaft 17 and the movable contact energizing shaft 1 formed by processing oxygen-free copper are used.
The silver plating applied on 8 was performed in the following steps. That is, degreasing → washing with water → pickling → washing with water → neutralization → washing with water (including hot water washing) → drying → masking → degreasing → washing with water → Kirinse treatment → washing with water → neutralization → washing with water → washing with acid → washing with nickel → plating with nickel → washing with water → Neutralization → Copper strike plating → Rinsing → Silver strike plating → Silver plating → Rinsing → Masking removal →
Washing → washing with water → bright treatment → washing with water → chromate treatment → washing with water → drying. The masking described above does not perform plating on the entire surface of the fixed contact energizing shaft 17 and the movable contact energizing shaft 18, but instead applies plating to the contact portion on the circuit breaker side where the vacuum valve 10 is mounted, and plating other portions. I go to not give. Thus, the fixed contact energizing shaft 1
7 and the movable contact energizing shaft 18 on the silver plating film,
Silver plating is performed after the formation of the thin film nickel plating film, the thin film copper plating film, and the thin film silver plating film. The plating layer of nickel or the like is formed of a barrier for preventing the disappearance of silver plating from the surface due to interdiffusion of metals in order to perform a high-temperature heat treatment for bonding by brazing or the like after silver plating on the current-carrying shaft. However, even if the barrier layer is formed as described above, there is a possibility that the silver plating disappears from the surface. When ordinary wet electroplating is performed on a complex shape, variations in plating thickness always occur. In addition, in the silver plating step described above, the pure copper base material may be dissolved by performing the treatment for a long time, particularly during the pickling step, and the skin may become thin. Furthermore, after silver plating, after joining (high-temperature heat treatment) by brazing, etc., when reworking when the silver plating disappears from the surface, partial plating must be applied because it is already assembled as a vacuum valve. And brush plating (wet). At this time, a necessary plating function cannot be obtained unless a normal pretreatment step such as removal of an oxide film is performed instead of performing plating immediately. For this reason, it becomes an offline manual operation using chemicals, and it is not only difficult to ensure safety, but also the chemicals penetrate and are not removed particularly on the movable contact energizing shaft 18 side (the color of water and the chemicals are the same, and the It is difficult to determine whether or not the chemical has been removed with water, and it is possible to damage metals and the like. Further, even if such post plating is applied to the unevenness of the threaded portion of the current-carrying shaft, it is difficult to form the plating uniformly, and stable quality cannot be ensured.

[0009] The present invention has been made in view of the above,
A first object is to provide a highly reliable circuit breaker having a high current carrying capacity. A second object is to provide a method of manufacturing a vacuum valve capable of manufacturing a highly reliable vacuum valve. The third object is to replace the silver plating with the required electrical characteristics including good conductivity and low contact resistance on the fixed contact energizing axis and the movable contact energizing axis in a shortened processing step, and the copper base material. An object of the present invention is to provide a method of manufacturing a vacuum valve that can provide a protection function. A fourth object of the present invention is to provide a method of manufacturing a vacuum valve capable of easily performing rework and repair of a film with the same material and obtaining stable quality. A fifth object of the present invention is to provide a method of manufacturing a vacuum valve capable of shortening a treatment step and preventing a thinning of a copper base material in an acid washing step. A sixth object is to obtain a stable function without causing a metal interdiffusion in a film portion due to the effect of a high-temperature heat treatment as in silver plating, and without forming a metal film in multiple layers. To provide a method of manufacturing a vacuum valve.

[0010]

According to a first aspect of the present invention, there is provided a circuit breaker having a resistivity of 10 ⁻³ Ω · m at a joining surface of a main circuit current conducting portion and a conducting member fastening portion. The gist of the present invention is that a solvent having the following conductivity is applied, the fastening is performed in a state of a hardness of 40 Hv or less, and the solvent is dried and cured. With this configuration, the small air gap usually present in the fastening portion of the current-carrying member is reliably filled with a solvent having good conductivity, the contact area is increased, the contact electric resistance and the contact thermal resistance are reduced, and the temperature due to heat generation is reduced. The rise is suppressed and the thermal conductivity is improved.

A circuit breaker according to a second aspect of the present invention is constructed by inserting and fastening a conductive thin film having a thickness of 50 μm or less and a hardness of 40 Hv or less at a joining surface of a main circuit current conducting portion and a conducting member fastening portion. The gist is to become With this configuration, the small air gap normally present in the current-carrying member fastening portion is reliably filled with the conductive thin film, and the contact area is increased, so that substantially the same operation as the first aspect of the invention is produced.

According to a third aspect of the present invention, there is provided the circuit breaker according to the first or second aspect, wherein the circuit breaker includes a vacuum valve and is configured as a vacuum circuit breaker. The gist of the present invention is that it is a screw connection part between a contact energizing shaft and a clamp for electrically connecting either the flexible conductor or the slide contact to the movable contact energizing shaft. With this configuration, since the screw contact portion between the movable contact energizing shaft and the clamp is a portion where the screw is engaged, the entire surface does not come into contact, and the tendency to generate a small air gap in particular increases. The middle gap is reliably filled with a solvent or a conductive thin film having good conductivity, and the contact area is increased to reduce the contact electric resistance and the contact thermal resistance.

According to a fourth aspect of the present invention, in the circuit breaker of the first, second or third aspect, the main components of the conductive solvent and the conductive thin film are Ag. . With this configuration, the conductivity and thermal conductivity of the solvent and the conductive thin film are further improved.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a vacuum valve.
After the required parts of the vacuum valve are joined by brazing by high-temperature heat treatment, a coating is formed on the fixed contact energizing shaft and the movable contact energizing shaft formed of copper material using a conductive paint containing a silver filler and a synthetic resin binder. Is the gist. With this configuration, instead of silver plating, a film is formed with a good adhesion using a conductive paint containing a silver filler and a synthetic resin binder on the fixed contact energizing axis and the movable contact energizing axis after the high-temperature heat treatment, The required electrical properties, including conductivity and low contact resistance, and protection of the copper matrix are provided. The pretreatment for brazing includes pickling and the like, but the copper base material is only slightly etched in order to obtain a clean metal surface, and the copper base material does not become thin.

According to a sixth aspect of the present invention, there is provided a method of manufacturing a vacuum valve.
In the method for manufacturing a vacuum valve according to the fifth aspect, a chromic acid film is formed on the fixed contact energizing shaft and the movable contact energizing shaft before the high temperature heat treatment. With this configuration, the formation of the copper oxide film is suppressed, the wettability of the brazing at the brazing joint is improved, and the function of maintaining the high vacuum tightness of the vacuum valve is enhanced.

[0016]

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

FIGS. 1 to 3 show an embodiment of a circuit breaker.
This will be described with reference to FIG. This embodiment is applied to a vacuum circuit breaker. 1 is a sectional side view of a vacuum circuit breaker, and FIG.
FIG. 3 is an enlarged sectional view of a portion A of FIG. 1, and FIG. 3 is an enlarged sectional view of a portion B of FIG. In FIGS. 1 to 3, the same or equivalent components as those in FIG. 4 are denoted by the same reference numerals as those in FIG.

As shown in FIG. 2, in this embodiment, before fastening the clamp 6 to the movable contact energizing shaft 18 with bolts, a conductive solvent 9 having a resistivity of 10 ⁻³ Ω · m or less is applied. Then, with the solvent 9 having a hardness of 40 Hv or less, the clamp 6 is fastened to the movable contact energizing shaft 18 for drying and curing. The hardened solvent 9 is buried in the gap between the movable contact energizing shaft 18 and the screw contact portion of the clamp 6, and the movable contact energizing shaft 1
The contact area between the clamp 8 and the clamp 6 increases.

According to this structure, a small air gap at the screw contact portion between the movable contact energizing shaft 18 and the clamp 6 is eliminated, so that the contact area is increased, the contact electric resistance is reduced, and the temperature rise due to heat generation is suppressed. You. Further, the contact thermal resistance is reduced, and the thermal conductivity is improved.

A small air gap also exists at the joint between the fixed contact energizing shaft 17 and the energizing conductor 5. However, as shown in FIG. The same operation and effect as described above can be obtained by applying and fastening the current-carrying conductor 5 to the fixed contact current-carrying shaft 17 with the solvent 9 having a hardness of 40 Hv or less. That is, the operation and effect of the configuration of FIGS. 2 and 3 can be applied to all portions of the current-carrying conductor fastening portion in the circuit breaker.

When a conductive thin film having a thickness of 50 μm or less and a hardness of 40 Hv or less is used instead of the solvent 9, the same operation and effect as described above can be obtained. Further, when the main components of the solvent and the conductive thin film are made of Ag, the resistivity of the solvent and the conductive thin film can be further reduced, and the thermal conductivity can be improved.

An embodiment of a method for manufacturing a vacuum valve will be described. First, the configuration of the present embodiment will be described. FIG. 6
Degreasing (alkali aqueous solution) -water washing-pickling (using sulfuric acid and nitric acid, sulfuric acid-water washing-nitric acid in the order of the former 10)
About 30 seconds, the latter about 2 to 5 seconds for short time treatment)
Chromate (using chromic anhydride + sulfuric acid in about 2 to 5 seconds) -water washing (including hot water washing) -drying. After that, the fixed contact energizing axis and the movable contact energizing axis and the corresponding fixed contact and movable contact, the fixed side metal end plate and the fixed setting energizing axis, the movable contact energizing axis and one end of the bellows, the movable side metal end plate and the bellows The other end and each joining portion of each metal end plate and the insulating cylinder are joined by brazing. The brazing material was eutectic silver brazing (Ag72-Cu28), silver brazing (Ag60-
Cu40), palladium solder (Ag58-Cu32-P)
Using d10) or the like, heat treatment is performed at a temperature not lower than the temperature at which these brazing agents (fusing materials) are melted (minimum processing temperature: eutectic silver solder 779 ° C, silver solder 830 ° C, palladium solder 850).
° C). In particular, when brazing is performed using eutectic silver brazing, a process of maintaining a high vacuum state is performed. After the joining is completed, at room temperature, a conductive paint obtained by mixing a silver filler and an acrylic synthetic resin binder is diluted with a solvent (thinner having a dissolving power) and then applied using a brush or a spray coater. After the application, the coating may be left at room temperature (drying), but in order to obtain a stable quality quickly, forced (accelerated) drying is performed at 40 to 80 ° C. for 10 to 60 minutes using a drying furnace. In this way, a conductive coating film is formed on the surfaces of the stationary contact energizing shaft and the movable contact energizing shaft.

Next, the operation of the present embodiment will be described. A description will be given of the execution of degreasing, washing, pickling, washing with water, chromate treatment, washing with water (including washing with hot water), and drying of the fixed contact energizing shaft and the movable contact energizing shaft. Degreasing has the effect of removing impurities such as grease and dirt on the metal surface, and pickling removes the copper oxide film formed during processing or when left in the air (including moisture), leaving a clean metal surface. It is intended to be. For this reason, the oxygen-free copper base material is only slightly etched (1 μm or less), and does not cause thinning. Normally, it is only necessary to be able to hold this clean metal surface in the air in a state where it is exposed (an oxide film is formed even in a short period of time during the rinsing-drying process), but this is extremely difficult. Even in the state immediately after this treatment, the surface is in an extremely active state, and is in a state where the reaction is easy. Therefore, a chromate treatment is performed to prevent discoloration of oxygen-free copper (a copper oxide film formed in the air).
A chromic acid film of about μm or less is formed. The formed chromic acid film has been formed conventionally and does not impair the performance of the vacuum valve, that is, the electrical characteristics. If such a treatment is not performed, not only does the wettability and the capillary phenomenon of the brazing at the joints such as brazing are inhibited, but also the degree of vacuum in the vacuum valve having the function of maintaining high vacuum tightness is reduced. The atmosphere in the vacuum furnace used to create the vacuum will also be significantly reduced. After the above processing,
A high-temperature (780 ° C. or higher) heat treatment (in a high vacuum or in a hydrogen reducing atmosphere) for bonding such as brazing is performed. After performing this treatment, a conductive paint in which a silver filler and an acrylic synthetic resin binder are mixed is applied and dried (normal temperature drying or forced drying at 40 to 80 ° C. for 10 to 60 minutes) to obtain a conductive coating film. Is formed to obtain required electric characteristics. Dry film thickness is 20-30 μm (10-100 μm)
And The conductivity is of the order of 10 ⁻⁵ Ω · cm and has good conductivity.

According to the above-described embodiment, the following effects are obtained. First, basic characteristics will be described. Adhesion: ASTM D3359B adhesion test 5B
(Good). Hardness: JISK5400 pencil scratch test H-2H (good). Conductivity: 3.5 × 10 ⁻⁵ Ω · cm
(1.0 to 9.9 × 10 ⁻⁵ Ω · cm). Function as protective film: (a) 100 cycles of gas phase thermal test (115
4H → ← -20 ° C, 4H) No abnormalities in appearance, adhesion 5
B is good. (B) 10 cycles of liquid phase cooling test (100
° C, 1H → ← 0 ° C, 1H) No abnormality in appearance and good adhesion strength of 5B. (C) Hydrogen sulfide gas test 10 ppm 40 ° C 90
% RH 60 days, good discoloration but good adhesion 5B →
The oxygen-free copper base metal does not deteriorate. (D) Sulfurous acid gas test 25
ppm 40 ° C. 90% RH 60 days, appearance is discolored, but adhesion is good at 5B → Oxygen-free copper of base material does not deteriorate.
(E) Nitrogen dioxide gas test 10 ppm 40 ° C 90%
RH 60 days, although there is discoloration in appearance, good with adhesion strength of 5B → Oxygen-free copper of base material does not deteriorate. The characteristics of (c), (d), and (e) are those plated with silver and do not have a protective function for the base material.

Next, the conductivity and the contact resistance will be described by comparing this embodiment with a conventional example.

<% Conductivity (based on copper) (%)> This embodiment: 80 to 100 Conventional example: 80 to 100, which is the same level.

[0027]

[Table 1] <Contact resistance value (μΩ)> Self-closing force 45kgf press 120kgf press 210kgf press Embodiment 40-55 25-35 20-30 15-20 Conventional example 40-55 25-35 20 ~ 30 15 ~ 20 Contact resistance values are at the same level. in this way,
The conductivity and the contact resistance have characteristics equal to or higher than those of the conventional example.

As described above, in this embodiment, not only can the performance equal to or higher than that of the conventional example be obtained, but also processing can be performed after joining such as brazing (after assembly is completed). It becomes unnecessary. Also, after coating film formation,
When there is a portion that has not been applied or when it is soiled, repair and repair can be easily performed. The repair can be easily performed with the same kind of material, and the formed coating film can obtain stable quality with the same electrical characteristics as a normal coating film. And, if you have coating equipment and equipment (including accelerated drying furnace) (for vacuum valves, there are some models for which coating for rust prevention, insulating varnish treatment for obtaining electrical characteristics, etc. are essential. Yes), and can be processed by these facilities and equipment. Furthermore, when compared with silver plating, the function of protecting the base material is better with the conductive coating having a synthetic resin as a binder, and can maintain the properties of the base metal even in a corrosive environment.

The synthetic resin used for the conductive paint is:
In addition to the acrylic resin, a polyester resin, a phenol resin, an epoxy resin, a melamine resin, a urethane resin, or the like can be used.

[0030]

As described above, according to the circuit breaker of the first aspect, the conductive circuit having a resistivity of 10 ⁻³ Ω · m or less is provided on the joining surface of the main circuit current conducting portion and the conducting member fastening portion. Is formed by applying a solvent having a hardness of 40 Hv or less and drying and curing the solvent, so that the contact electric resistance is reduced, the current carrying capacity is increased, the temperature rise due to heat generation is suppressed, and the contact heat is reduced. The resistance is reduced, the thermal conductivity is improved, and the reliability is improved.

According to the circuit breaker of the second aspect, the thickness of the main circuit current conducting portion and the joining surface of the conducting member fastening portion is 50 mm.
Since the conductive thin film having a thickness of not more than μm and a hardness of not more than 40 Hv is inserted and fastened, it has substantially the same effect as the effect of the first aspect of the present invention.

According to a third aspect of the present invention, the circuit breaker is configured as a vacuum circuit breaker having a vacuum valve mounted thereon, and the fastening portion includes at least a movable contact energizing shaft of the vacuum valve;
Since the movable contact energized shaft has a screw contact portion with a clamp for electrically connecting either the flexible conductor or the slide contact, the screw is engaged at the screw contact portion between the movable contact energized shaft and the clamp. Since it is a part, the entire surface does not come into contact, and the tendency to generate minute air gaps in particular increases, but this air gap is reliably filled with a solvent or conductive thin film having good conductivity, Electrical resistance and contact thermal resistance are reduced, and reliability is significantly improved.

According to the circuit breaker of the present invention, since the main component of the conductive solvent and the conductive thin film is Ag, the conductivity and the thermal conductivity of the solvent and the conductive thin film are further improved. In addition, the contact electric resistance and the contact heat resistance can be further reduced.

According to the method for manufacturing a vacuum valve according to the fifth aspect, after a required portion of the vacuum valve is brazed and joined by high-temperature heat treatment, a silver filler is applied to a fixed contact energizing shaft and a movable contact energizing shaft formed of copper material. And a conductive coating containing a synthetic resin binder to form the coating. Therefore, instead of silver plating, good conductivity and low contact resistance are applied to the fixed contact current axis and the movable contact current axis in a shortened processing step. , And the protective function of the copper base material can be provided. Rework and repair of the film can be easily performed with the same material, and stable quality can be obtained. The pretreatment for brazing includes pickling, but unlike the pretreatment for silver plating, the copper base material surface is only slightly etched for the purpose of producing a clean metal surface. Does not cause thinning of the base material. Further, since it is not affected by the high-temperature heat treatment, metal interdiffusion or the like does not occur unlike the case of silver plating, and a stable function can be obtained without forming a metal film in multiple layers.

According to a sixth aspect of the present invention, the chromic acid film is formed on the fixed contact energizing shaft and the movable contact energizing shaft before the high temperature heat treatment. Is suppressed, the wettability of the brazing at the brazing joint is improved, and the function of maintaining the high vacuum airtightness of the vacuum valve is enhanced, so that the reliability is improved.

[Brief description of the drawings]

FIG. 1 is a side view showing a partial cross section of an embodiment of a circuit breaker according to the present invention.

FIG. 2 is an enlarged sectional view of a portion A in FIG.

FIG. 3 is an enlarged sectional view of a portion B in FIG. 1;

FIG. 4 is a side view showing a partial section of a conventional circuit breaker.

FIG. 5 is an enlarged sectional view of a portion C in FIG. 4;

FIG. 6 is a longitudinal sectional view of a conventional vacuum valve.

[Explanation of symbols]

5 Conductive conductor forming a fastening part with a fixed contact energizing axis 6 Clamp forming a fastening part between a movable contact energizing axis and a screw contact part 7 Flexible conductor 9 Solvent 10 Vacuum valve 17 Fixed contact energizing axis 18 Moving contact energizing axis

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroki Kara 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Fuchu Plant, Inc. 72) Inventor Fumio Furuya 1 Toshiba-cho, Toshiba-cho, Fuchu-shi, Tokyo (72) Inventor Akira Magiwa 1-futoshi-cho, Toshiba-cho, Fuchu-shi, Tokyo In-futoshi, Toshiba Corporation

Claims (6)

[Claims] 1. A solvent having a resistivity of 10 ⁻³ Ω · m or less is applied to a joining surface of a current-carrying portion of a main circuit and a joining portion of a current-carrying member, and fastening is performed with a hardness of 40 Hv or less. A circuit breaker characterized by being formed by drying and curing. 2. A circuit interrupter comprising a main circuit current conducting portion and a conductive thin film having a thickness of 50 μm or less and a hardness of 40 Hv or less inserted and fastened to a joint surface of a fastening portion of a conducting member. vessel. 3. A vacuum circuit breaker having a vacuum valve mounted thereon, wherein the fastening portion includes at least a movable contact energizing shaft of the vacuum valve and either a flexible conductor or a slide contact on the movable contact energizing shaft. The circuit breaker according to claim 1, wherein the circuit breaker is a screw contact portion with a clamp for electrically connecting the circuit breaker. 4. The circuit breaker according to claim 1, wherein the main component of the conductive solvent and the conductive thin film is Ag. 5. A required portion of a vacuum valve is brazed and joined by high-temperature heat treatment. Then, a conductive paint containing a silver filler and a synthetic resin binder is used for a fixed contact energizing shaft and a movable contact energizing shaft formed of a copper material. A method for manufacturing a vacuum valve, comprising forming a coating. 6. The method of manufacturing a vacuum valve according to claim 5, wherein a chromic acid film is formed on the fixed contact energizing shaft and the movable contact energizing shaft before the high-temperature heat treatment.