JP7580672B1 - Vacuum circuit breaker and method for manufacturing the same - Google Patents

Abstract

A fixed contact (5a) and a movable contact (5b) are provided inside the vacuum valve (5), and the movable contact (5b) is connected to a movable electrode shaft (5c). The movable electrode shaft (5c) is connected to a bellows (5d) and supported by a bearing (5h). The bearing (5h) is fixed to a bearing mounting part (5g) with a bolt. A fixed airtight part (5j) is provided to hermetically seal the surface where the bearing (5h) is fixed to the bearing mounting part (5g). The bearing (5h) is provided with an airtight sliding part (5k) to hermetically seal the sliding surface with the movable electrode shaft (5c).

Description

The present disclosure relates to a vacuum circuit breaker and a method for manufacturing a vacuum circuit breaker.

A gas-insulated switchgear is composed of a main circuit section to which a high voltage is applied, an operating mechanism section that drives the switches in the main circuit section, and a control circuit section. The main circuit section of the gas-insulated switchgear is placed in a container in which a gas with high insulating performance is pressurized and sealed, and by increasing the pressure of the insulating gas, the insulating performance is improved and the entire switchgear is made more compact. SF6 gas, which has high insulating performance, is generally used as the insulating gas, but because SF6 gas has a high global warming potential, gas-insulated switchgears that pressurize and seal dry air, which has no impact on the environment, have also been commercialized in recent years.

Among the main circuit switches, circuit breakers capable of interrupting large currents include gas circuit breakers that use gases with excellent arc extinguishing performance, such as SF6 gas, and vacuum circuit breakers that use a vacuum valve in the arc extinguishing chamber. Vacuum circuit breakers were first used in low voltage classes, but with growing concern for the environment in recent years, there has been a growing need for vacuum circuit breakers that have no impact on the environment, rather than gas circuit breakers that use SF6 gas, which has a high global warming potential, and vacuum circuit breakers are gradually being used in higher voltage classes.

In this way, gas-insulated switchgear equipped with vacuum circuit breakers are beginning to be applied to higher voltage classes. The vacuum valve, which serves as the arc quenching chamber of the vacuum circuit breaker, is made of metal such as stainless steel or copper brazed to an insulator such as ceramic and is sealed, and the inside of the container is maintained in a high vacuum state. Inside the vacuum valve are contacts that open and close high voltages and large currents, one contact is fixed to the vacuum valve container and the other contact is designed to be movable to open and close.

A metal bellows is used for the moving parts of a vacuum valve, and because the bellows has a cylindrical, elastic bellows structure, it is possible to open and close the contacts while maintaining a high vacuum inside the vacuum valve. Here, stress is constantly generated in the bellows of the vacuum valve due to the pressure difference between the surrounding pressure and the vacuum inside the vacuum valve. For example, when a vacuum valve is used at atmospheric pressure, a pressure of 1 atmosphere, which is the pressure difference between atmospheric pressure and the vacuum, is constantly generated in the bellows part. In addition, because the bellows expands and contracts when the contacts of the vacuum valve are opened and closed, stress is also generated in the bellows due to the expansion and contraction of the contacts when the contacts are opened and closed. For this reason, the bellows is one of the mechanical weak points of the vacuum valve.

Furthermore, in gas-insulated switchgear, increasing the gas pressure inside the gas-insulated switchgear container improves insulation performance and allows the device itself to be made more compact, so the pressure inside the container of high-voltage gas-insulated switchgear is higher. When a vacuum valve is applied to a high-voltage gas-insulated switchgear, stress is generated in the bellows of the vacuum valve due to the pressure difference between the high pressure inside the gas-insulated switchgear container and the vacuum inside the vacuum valve, so that the stress on the bellows due to the pressure difference is greater than when the vacuum valve is used at atmospheric pressure, resulting in a shorter lifespan relative to the number of times the bellows is opened and closed.

In the configuration shown in Figure 4 of Patent Document 1, an intermediate chamber is formed by hermetically sealing the movable side of the vacuum valve with an insulating cylinder, and the pressure in this intermediate chamber is set to a pressure halfway between atmospheric pressure and vacuum, thereby reducing the pressure difference and stress on the bellows of the vacuum valve.
1 of Patent Document 1, two bellows, a first bellows and a second bellows, are used in the intermediate chamber, and the pressure in the intermediate chamber is set to an intermediate pressure between high pressure and vacuum. In this case, stress is generated in the second bellows due to the pressure difference between the high pressure and the intermediate pressure, and stress is generated in the other first bellows due to the pressure difference between the high pressure and the intermediate pressure.

JP2004-236455

In the configuration of Fig. 4 of the above-mentioned Patent Document 1, a high voltage is also applied to the movable rod part in the intermediate chamber, and the pressure in the intermediate chamber is a low pressure between atmospheric pressure and vacuum, so the insulation performance in the gas is low. Therefore, in order to withstand high voltage insulation, it is necessary to increase the insulation distance, which makes it difficult to miniaturize the product.

In addition, the configuration shown in FIG. 1 of Patent Document 1 uses two bellows, which makes the vacuum valve itself larger. In addition, the stress caused by the pressure difference on the bellows is greater than that of the configuration shown in FIG. 4 of Patent Document 1, resulting in a shorter mechanical life of the bellows.

This disclosure discloses technology for solving the problems described above, and aims to provide a vacuum circuit breaker that allows parts other than the vacuum valve to be insulated by high-pressure insulating gas and enables the entire gas-insulated switchgear to be miniaturized.

The vacuum circuit breaker of the present disclosure has a vacuum valve attached inside a sealed container, and a high-pressure insulating gas is sealed in the space inside the sealed container,
A fixed contact and a movable contact are installed inside the vacuum valve, and the movable contact is connected to a movable electrode shaft.
the movable electrode shaft is connected to a bellows and supported by a bearing, the bearing being fixed to a bearing mounting portion by a bolt;
a fixing airtight part for airtightly sealing a surface where the bearing is fixed to the bearing attachment part;
The bearing is provided with an airtight sliding portion for airtightly sealing the sliding surface with the movable electrode shaft, the bearing is made of metal, and an insulating sheet is sandwiched between the bearing attachment portion and the bearing.
In addition, the manufacturing method of the vacuum circuit breaker disclosed herein includes a vacuum valve mounted in a sealed container, and a high-pressure insulating gas is sealed in the space within the sealed container,
A fixed contact and a movable contact are installed inside the vacuum valve, and the movable contact is connected to a movable electrode shaft.
the movable electrode shaft is connected to a bellows and supported by a bearing, the bearing being fixed to a bearing mounting portion by a bolt;
A method for manufacturing a vacuum circuit breaker, comprising the steps of: providing a fixing airtight part for airtightly sealing a surface where the bearing is fixed to the bearing attachment part; and providing an airtight sliding part in the bearing for airtightly sealing a sliding surface between the bearing and the movable electrode shaft,
preparing the bearing in which a first seal part is attached to a groove part of the fixed airtight part and a second seal part is attached to a groove part of the airtight sliding part;
The process comprises a step of attaching the bearing to the movable electrode shaft with the fixed contact and the movable contact in contact with each other in the air, and fixing the bearing with a bearing fixing bolt, thereby sealing the air in the inner space of the bellows.
In addition, a method for manufacturing a vacuum circuit breaker according to the present disclosure includes the steps of: attaching a vacuum valve to a sealed container; and sealing a high-pressure insulating gas in a space within the sealed container;
A fixed contact and a movable contact are installed inside the vacuum valve, and the movable contact is connected to a movable electrode shaft.
the movable electrode shaft is connected to a bellows and supported by a bearing, the bearing being fixed to a bearing mounting portion by a bolt;
A method of manufacturing a vacuum circuit breaker, comprising the steps of: providing an airtight fixing part for airtightly sealing a surface where the bearing is fixed to the bearing attachment part; providing an airtight sliding part in the bearing for airtightly sealing a sliding surface between the bearing and the movable electrode shaft; and sealing air, dry air or an inert gas in an inner peripheral space of the bellows,
preparing the bearing in which a first seal part is attached to a groove part of the fixed airtight part and a second seal part is attached to a groove part of the airtight sliding part;
The process comprises a step of attaching the bearing to the movable electrode shaft with the fixed contact and the movable contact in contact within an enclosed assembly work space filled with dry air or inert gas, and fixing the bearing with a bearing fixing bolt, thereby sealing the dry air or inert gas in the inner space of the bellows.
Further, another method for manufacturing a vacuum circuit breaker according to the present disclosure includes mounting a vacuum valve in a sealed container, and sealing a high-pressure insulating gas in a space within the sealed container,
A fixed contact and a movable contact are installed inside the vacuum valve, and the movable contact is connected to a movable electrode shaft.
the movable electrode shaft is connected to a bellows and supported by a bearing, the bearing being fixed to a bearing mounting portion by a bolt;
A method for manufacturing a vacuum circuit breaker, comprising the steps of: providing a fixing airtight part for airtightly sealing a surface where the bearing is fixed to the bearing attachment part; and providing an airtight sliding part in the bearing for airtightly sealing a sliding surface between the bearing and the movable electrode shaft,
A gas supply hole is provided in the bearing, and after the bearing is attached to the movable electrode shaft, the air in the inner space of the bellows is evacuated via the gas supply hole, and gas is sealed in the inner space via the gas supply hole.

According to the vacuum circuit breaker and manufacturing method for the vacuum circuit breaker disclosed herein, parts other than the vacuum valve can be insulated by high-pressure insulating gas, and the entire gas-insulated switchgear can be made smaller.

1 is a side cross-sectional view showing a gas-insulated switchgear according to a first embodiment. FIG. 2 is a schematic diagram showing a vacuum circuit breaker unit of a gas-insulated switchgear as a comparative example. 1 is a schematic diagram showing a vacuum circuit breaker section of a gas-insulated switchgear according to a first embodiment. FIG. 2 is an enlarged view showing a portion around a bearing of a movable electrode shaft of the vacuum interrupter according to the first embodiment. FIG. 1 is a schematic diagram showing a vacuum circuit breaker section of a gas-insulated switchgear according to a first embodiment. FIG. 11 is an enlarged view showing the surrounding area of a bearing of a movable electrode shaft of a vacuum interrupter according to a second embodiment. FIG. 11 is an enlarged view showing the surrounding area of the bearing of the movable electrode shaft of the vacuum interrupter according to embodiment 3. FIG.

Embodiment 1.
The present embodiment relates to a vacuum circuit breaker, and more particularly to a vacuum valve structure of a vacuum circuit breaker.
The contents described in this embodiment can be used for a vacuum circuit breaker of a gas-insulated switchgear.
1 is a side cross-sectional view showing a gas-insulated switchgear having a vacuum circuit breaker. The gas-insulated switchgear 1 includes a vacuum circuit breaker 2, a disconnecting switch and earthing switch 6, a bus bar 7, a power cable 9, etc., mounted in an airtight container 8, which is filled with an insulating gas such as dry air.
The vacuum circuit breaker 2 is composed of a vacuum circuit breaker operating mechanism 3 arranged outside the sealed container 8 and a vacuum circuit breaker main circuit section 4 arranged inside the sealed container 8, and the vacuum circuit breaker vacuum valve 5 is located inside the vacuum circuit breaker main circuit section 4.
2 is a schematic diagram showing a vacuum circuit breaker section of a gas-insulated switchgear as a comparative example to this embodiment. High-pressure insulating gas is sealed in a space 8a within a sealed container 8. A fixed contact 5a and a movable contact 5b are provided inside a vacuum valve 5, and the movable contact 5b is connected to a movable electrode shaft 5c.

The movable electrode shaft 5c is connected to a bellows 5d, and the inside of the vacuum valve 5 is kept at a vacuum. The other end of the bellows 5d is attached to a container 5w that constitutes the vacuum valve 5. The movable electrode shaft 5c passes through the inner space 5f of the bellows 5d and protrudes outside the vacuum valve 5. The movable electrode shaft 5c is supported by a movable electrode shaft bearing 5e, which is fixed to the bearing mounting portion 5g by a bolt. The movable electrode shaft bearing 5e is made of a thermoplastic or thermosetting resin. The reason for this is that the large current flowing through the vacuum circuit breaker flows via the fixed contact 5a, the movable contact 5b, and the movable electrode shaft 5c, but if the bearing 5e of the movable electrode shaft were made of metal, a current path would be created passing through the fixed contact 5a, the movable contact 5b, the movable electrode shaft 5c, the bellows 5d, the bearing attachment portion 5g, the bearing 5e of the movable electrode shaft, and the movable electrode shaft 5c, and current would also flow through this current path, causing damage to the bellows 5d. Therefore, by making the bearing 5e from a thermoplastic or thermosetting resin, current is prevented from flowing through the bellows 5d.

The movable electrode shaft 5c protruding from the vacuum valve 5 is connected to an insulating operating rod 10, which is connected to a vacuum circuit breaker operating shaft 12. The vacuum circuit breaker operating shaft 12 protrudes to the outside of the sealed container 8 through an airtight sliding part 11 and is connected to a vacuum circuit breaker operating mechanism 3 (see FIG. 1) not shown in FIG. 2. The bearing 5e of the movable electrode shaft only mechanically supports the movable electrode shaft 5c, and does not shield it airtight. Therefore, the inner space 5f of the bellows 5d contains the same high-pressure insulating gas as the space 8a inside the sealed container 8.

Figure 3 is a schematic diagram showing the vacuum circuit breaker part of the gas-insulated switchgear according to embodiment 1. The difference between Figure 2 and Figure 3 is that the bearing 5e of the movable electrode shaft shown in Figure 2 is changed to the bearing 5h of the movable electrode shaft of the vacuum valve according to embodiment 1 in Figure 3, and the rest of Figure 3 is the same as Figure 2. Note that Figure 3 shows the circuit breaker contacts in an open state. Also, the bearing 5h of the movable electrode shaft is made of thermoplastic or thermosetting resin for the same reasons as those explained for the bearing 5e in Figure 2.

FIG. 4 is an enlarged view showing the periphery of the bearing 5h of the movable electrode shaft of the vacuum interrupter shown in FIG.
In the movable electrode shaft bearing 5h of the vacuum valve according to the first embodiment, there is a groove for the fixed airtight part 5j for airtightly sealing the surface fixed to the bearing mounting part 5g, and a structure that can be airtight by attaching a sealing part such as an O-ring or packing. The movable electrode shaft bearing 5h also has a groove for the airtight sliding part 5k for airtightly sealing the sliding surface with the movable electrode shaft 5c, and a sealing part such as a T-ring, an X-ring, or a sealing part combining resin and a spring is attached. This structure allows airtight sliding when the movable electrode shaft 5c is in operation.
A T-ring is a ring with a T-shaped cross section, and Figure 4 shows the case where a T-ring is used. An X-ring is a ring packing with a nearly square X-shaped cross section. Balseal (registered trademark) manufactured by Balseal is assumed as a sealing part that combines resin and a spring.
In general, a high vacuum state cannot be maintained inside a vacuum valve used in a vacuum circuit breaker unless a bellows is used.
The bellows 5d is essential to drive the movable electrode shaft 5c while maintaining a high vacuum state. The airtight sliding part 5k can slide airtightly with a rubber T-ring, but this is intended only for the purpose of gas tightness. A rubber T-ring or the like can achieve gas tightness and can maintain a low vacuum for a short period of time, but a rubber T-ring or the like cannot maintain a high vacuum.

Figure 5 is a schematic diagram showing the vacuum circuit breaker part of the gas-insulated switchgear according to embodiment 1. In Figure 3, the circuit breaker contacts are shown in an open state, whereas in Figure 5, the circuit breaker contacts are shown in a closed state. The difference between Figure 3 and Figure 5 is that while the contacts are open in Figure 3, the movable contact 5b moves toward the fixed contact 5a in Figure 5 to close the contacts, and the movable electrode shaft 5c, the insulated operating rod 10, and the vacuum circuit breaker operating shaft 12, which are connected to the movable contact 5b, also move toward the fixed contact 5a. In addition, with the movement of the movable electrode shaft 5c, the bellows 5d expands, and the inner circumferential space 5f of the bellows becomes larger.

When the vacuum valve is manufactured, the contacts of the vacuum valve 5 are in a closed state, as shown in Fig. 5. This is because the internal space 5m of the vacuum valve is a vacuum, and the inner space 5f of the bellows is at atmospheric pressure, so the movable contacts 5b are pressed by the pressure difference.
Next, a method of attaching the bearing 5h of the movable electrode shaft to the vacuum valve 5 to make the inner space 5f of the bellows a sealed space will be described. When sealing the inner space 5f of the bellows to normal air, a seal part (first seal part) such as an O-ring or packing is attached to the groove of the fixed airtight part 5j of the bearing 5h of the movable electrode shaft, and a seal part (second seal part) such as a T-ring, an X-ring, or a seal part combining resin and a spring is attached to the groove of the airtight sliding part 5k. Then, with the contacts of the vacuum valve closed in air, the bearing 5h of the movable electrode shaft is attached and fixed with the bearing fixing bolts 5i.

When sealing dry air or inert gas in the inner space 5f of the bellows, a vacuum valve and a bearing 5h for the movable electrode shaft are prepared in the sealed space for assembly work, the sealed space for assembly work is filled with dry air or inert gas, and then the bearing 5h is attached in the sealed space for assembly work and fixed with the bearing fixing bolts 5i to complete the work.
That is, in this case, a first seal part is attached to the groove of the fixed airtight part 5j, and a bearing 5h is prepared with a second seal part attached to the groove of the airtight sliding part 5k. The bearing 5h is attached to the movable electrode shaft 5c with the fixed contact 5a and the movable contact 5b in contact in an enclosed space for assembly work filled with dry air or inert gas, and the bearing 5h is fixed by the bearing fixing bolt 5i, thereby sealing the dry air or inert gas in the inner space 5f of the bellows 5d.
During the manufacture of the vacuum valve 5, no insulating gas is present in the sealed container 8. After the vacuum valve 5 is manufactured, the vacuum valve 5 and other components are assembled in the sealed container 8, the sealed container 8 is closed with a lid, and finally, the insulating gas is sealed in the space 8a within the sealed container 8.

In the case of the vacuum circuit breaker structure according to the first embodiment shown in Figures 3 to 5, the above manufacturing process causes the bellows inner space 5f to be at atmospheric pressure when the contacts of the vacuum valve 5 are closed. If the volume of the bellows inner space 5f when the contacts of the vacuum valve 5 are closed (Figure 5) is V, the pressure is P, and the volume of the bellows inner space 5f when the contacts of the vacuum valve 5 are open is V1, then the pressure in the bellows inner space 5f when the contacts of the vacuum valve 5 are open is V/V1 x P, and since V1 < V, the pressure in the bellows inner space 5f is slightly higher than atmospheric pressure by the volume ratio. However, since the high pressure due to the insulating gas in the space 8a in the sealed container 8 is not applied to the bellows inner space 5f, the stress due to the pressure difference on the bellows 5d can be reduced.

Furthermore, by setting the volume of the inner space 5f of the bellows to be large and setting the difference between volumes V and V1 to be small, it is possible to reduce pressure fluctuations in the inner space 5f of the bellows and extend the mechanical life of the bellows 5d.
On the other hand, since high-pressure insulating gas is sealed in the space 8a within the sealed container 8, the areas other than the vacuum valve, such as around the insulating operating rod 10, can be insulated by the high-pressure insulating gas, making it possible to miniaturize the entire device.

With the above configuration, the size of the vacuum valve 5 can be kept to the same external dimensions as the conventional product. The pressure on the inner periphery of the bellows is between atmospheric pressure and a pressure slightly higher than atmospheric pressure, and the bellows 5d is only subjected to stress due to the pressure difference between this pressure and the vacuum. Even if this vacuum valve 5 is placed in a gas-insulated switchgear 1 insulated with a high-pressure insulating gas, the pressure on the inner periphery of the vacuum valve 5 remains between atmospheric pressure and a pressure slightly higher than atmospheric pressure, and is not affected by the high pressure of the insulating gas around the vacuum valve 5. In addition, since the movable electrode shaft 5c and the insulating operating rod 10 of the vacuum valve 5 are insulated by an insulating gas having a high pressure, the gas-insulated switchgear 1 can be made smaller in size.
The gas compartment on the inner circumference side of the bellows is a space surrounded by the metal bellows 5d and the bearing 5h of the movable electrode shaft, and since almost no electric field is generated inside, there is no need to consider the insulation performance inside the gas compartment on the inner circumference side of the bellows. That is, an electric field is generated by a potential difference (voltage difference), but since there is no potential difference inside the metal bellows 5d, no electric field is generated. By sealing in dry air, it is possible to prevent condensation. Furthermore, by sealing in an inert gas, oxygen can be eliminated, making it possible to prevent deterioration due to oxidation.

Embodiment 2.
FIG. 6 is an enlarged view showing the periphery of the bearing of the movable electrode shaft of the vacuum valve according to the second embodiment. The difference from FIG. 4 in the first embodiment is that in FIG. 6, there is a hole for the gas supply port 5p of the bearing. The other points are the same as in FIG. 4. In the first embodiment, when the contacts of the vacuum valve are closed, air at atmospheric pressure, dry air or an inert gas is sealed in the inner space 5f of the bellows. In the second embodiment, a hole for the gas supply port 5p is provided in the bearing 5n, and after the bearing 5n is attached to the movable electrode shaft 5c, the air in the inner space 5f of the bellows is evacuated through the gas supply port 5p, and an arbitrary gas, for example an inert gas (a rare gas such as helium, neon, or argon, or nitrogen gas) is sealed in through the gas supply port 5p at an arbitrary pressure.

Since the gas supply port 5p is used only when the gas is charged, the hole of the gas supply port 5p is closed after the gas is charged.
As a specific example, when sealing any gas at atmospheric pressure in the inner space 5f of the bellows, the gas supply port 5p is made into a screw hole, a pipe is attached to this screw hole, the air in the inner space 5f of the bellows is evacuated, and any gas is sealed in so that the pressure becomes atmospheric. Even if the pipe is subsequently removed, the inner space 5f of the bellows and its surroundings are both at atmospheric pressure, so that almost no gas leaks. After that, the screw hole that is the gas supply port 5p is gas-sealed with a seal bolt or a bolt with a gas seal material such as an O-ring, thereby making the inner space 5f of the bellows a sealed space.

Furthermore, when sealing any gas at atmospheric pressure or higher in the bellows inner space 5f, the gas supply port 5p can be in the form of a pipe rather than a hole (screw hole). That is, the pipe can be attached by welding, for example. Then, the bellows inner space 5f can be evacuated using the pipe and the gas can be sealed in. After the gas is sealed in, the base of the pipe attached to the gas supply port 5p can be completely sealed to make the bellows inner space 5f a sealed space. That is, the pipe can be cut in an airtight manner by crushing the end of the pipe.
As a result, the space 5f on the inner periphery of the bellows is substantially free of oxygen, preventing oxidation of the bellows 5d and the movable electrode shaft 5c and maintaining their soundness for a long period of time.

Embodiment 3.
Fig. 7 is an enlarged view showing the periphery of the bearing of the movable electrode shaft of the vacuum valve according to embodiment 3. The difference from Fig. 4 in embodiment 1 is that in Fig. 7, an insulating sheet 5r is sandwiched between the bearing attachment part 5g and the bearing 5q. The insulating sheet here is made of rubber, nylon, PTFE (POLYTETRAFLUOROETHYLENE), or the like.
In the embodiment 1 shown in FIG. 4, the bearing 5h is made of resin, and the bearing fixing bolt 5i is made of metal. In contrast to this, in the embodiment 3 shown in FIG. 7, the bearing 5q is made of metal, and the bearing fixing bolt 5s is made of an insulating material. As the metal, a non-magnetic metal such as aluminum, copper, brass, or stainless steel is used. As the insulating material, a thermoplastic resin such as PET (POLY ETHYLENE TEREPHTHALATE) or PBT (POLY BUTYLENE TEREPHTALATE), or a thermosetting resin such as epoxy is used. Other points are the same as in the case of FIG. 4.

By making the bearing 5q a machined metal part, the dimensional accuracy is improved compared to resin products, and the mechanical performance as a bearing and the airtight performance are improved. Even if the bearing 5q is made of metal, by sandwiching the insulating sheet 5r and further making the bearing fixing bolt 5s out of an insulating material, there is no path through which current flows in the bellows 5d, so there is no impact on the life of the bellows 5d due to current flowing in the bellows 5d.

In addition, in the first to third embodiments, the case where dry air is used as the insulating gas is described, but other insulating gases such as SF6 gas may also be used.

Although the present application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations.
Therefore, countless modifications not exemplified are assumed within the scope of the technology disclosed in the present specification, including, for example, modifying, adding, or omitting at least one component, and further, extracting at least one component and combining it with a component of another embodiment.

1 Gas insulated switchgear, 2 Vacuum circuit breaker, 4 Main circuit section, 5 Vacuum valve, 5a Fixed contact, 5b Movable contact, 5c Movable electrode shaft, 5d Bellows, 5f Inner space, 5g Bearing mounting section, 5h Bearing, 5j Fixed airtight section, 5k Airtight sliding section, 5n Bearing, 5p Gas supply port, 5q Bearing, 5r Insulating sheet, 8 Sealed container.

Claims (7)

A vacuum circuit breaker having a vacuum valve attached inside a sealed container and a high-pressure insulating gas sealed in the space inside the sealed container,
A fixed contact and a movable contact are installed inside the vacuum valve, and the movable contact is connected to a movable electrode shaft.
the movable electrode shaft is connected to a bellows and supported by a bearing, the bearing being fixed to a bearing mounting portion by a bolt;
a fixing airtight part for airtightly sealing a surface where the bearing is fixed to the bearing attachment part;
the bearing is provided with an airtight sliding portion for airtightly sealing a sliding surface between the bearing and the movable electrode shaft;
The vacuum circuit breaker, wherein the bearing is made of metal and an insulating sheet is sandwiched between the bearing attachment portion and the bearing. 2. A vacuum circuit breaker according to claim 1, wherein when the contacts of the vacuum valve are closed, the pressure in the inner space of the bellows becomes atmospheric pressure, and when the contacts of the vacuum valve are open, the pressure in the inner space of the bellows increases above atmospheric pressure by an amount corresponding to a reduction in the volume of the inner space of the bellows. 3. The vacuum circuit breaker according to claim 2, wherein air, dry air or an inert gas is sealed in the inner peripheral space of the bellows. A vacuum valve is attached inside the sealed container, and a high-pressure insulating gas is sealed in the space inside the sealed container.
A fixed contact and a movable contact are installed inside the vacuum valve, and the movable contact is connected to a movable electrode shaft.
the movable electrode shaft is connected to a bellows and supported by a bearing, the bearing being fixed to a bearing mounting portion by a bolt;
A method for manufacturing a vacuum circuit breaker, comprising the steps of: providing a fixing airtight part for airtightly sealing a surface where the bearing is fixed to the bearing attachment part; and providing an airtight sliding part in the bearing for airtightly sealing a sliding surface between the bearing and the movable electrode shaft,
preparing the bearing in which a first seal part is attached to a groove part of the fixed airtight part and a second seal part is attached to a groove part of the airtight sliding part;
and attaching the bearing to the movable electrode shaft with the fixed contact and the movable contact in contact with each other in air, and fixing the bearing with a bearing fixing bolt, thereby sealing air in the inner space of the bellows. 5. A method for manufacturing a vacuum circuit breaker as claimed in claim 4, wherein when the contacts of the vacuum valve are closed, the pressure in the inner space of the bellows becomes atmospheric pressure, and when the contacts of the vacuum valve are open, the pressure in the inner space of the bellows increases above atmospheric pressure by an amount corresponding to a reduction in the volume of the inner space of the bellows. A vacuum valve is attached inside the sealed container, and a high-pressure insulating gas is sealed in the space inside the sealed container.
A fixed contact and a movable contact are installed inside the vacuum valve, and the movable contact is connected to a movable electrode shaft.
the movable electrode shaft is connected to a bellows and supported by a bearing, the bearing being fixed to a bearing mounting portion by a bolt;
a fixed airtight part is provided for airtightly sealing a surface where the bearing is fixed to the bearing attachment part, and an airtight sliding part is provided on the bearing for airtightly sealing a sliding surface between the bearing and the movable electrode shaft,
A method for manufacturing a vacuum circuit breaker in which air, dry air or an inert gas is sealed in an inner peripheral space of the bellows, comprising the steps of:
preparing the bearing in which a first seal part is attached to a groove part of the fixed airtight part and a second seal part is attached to a groove part of the airtight sliding part;
and attaching the bearing to the movable electrode shaft with the fixed contact and the movable contact in contact within an enclosed assembly space filled with dry air or inert gas, and fixing the bearing with a bearing fixing bolt, thereby sealing the dry air or inert gas in the inner space of the bellows. A vacuum valve is attached inside the sealed container, and a high-pressure insulating gas is sealed in the space inside the sealed container.
A fixed contact and a movable contact are installed inside the vacuum valve, and the movable contact is connected to a movable electrode shaft.
the movable electrode shaft is connected to a bellows and supported by a bearing, the bearing being fixed to a bearing mounting portion by a bolt;
A method for manufacturing a vacuum circuit breaker, comprising the steps of: providing a fixing airtight part for airtightly sealing a surface where the bearing is fixed to the bearing attachment part; and providing an airtight sliding part in the bearing for airtightly sealing a sliding surface between the bearing and the movable electrode shaft,
A manufacturing method for a vacuum circuit breaker, comprising the steps of: providing a hole for a gas supply port in the bearing; attaching the bearing to the movable electrode shaft; evacuating the air in the inner space of the bellows via the gas supply port; and sealing gas in the inner space via the gas supply port.

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