Vacuum valve

Abstract

To provide a vacuum valve excellent in insulation performance in low-cost capable of relaxing an electric field strength of a triple junction while utilizing existing metallization processing as it is.SOLUTION: A vacuum valve includes a non-metallic insulating container 1 having a hollow structure having openings K1, K2 and having end surfaces S1, S2 extending so as to surround each opening, metal-made sealing members 2, 3 having outer edges 2e 3e which can be disposed so as to face each end surface of the insulating container so as to close each opening of the insulating container, and bonding means 13 of bonding a sealing member to the insulating container. An embedding part 14 capable of embedding at least a part of an entire outer edge of the sealing member is provided on the end surface of the insulating container. When the embedding part is constructed so that the end surface is concaved in a concaved shape, and the sealing member is joined to the insulating container, at least a part of the entire outer edge of the sealing member is maintained in a state of being embedded in the embedding part without a gap via the bonding means.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a vacuum interrupter. [Background technology]

[0002] Switchgear equipped with switches such as circuit breakers and disconnectors is known as a type of switching device for receiving and distributing electricity installed in buildings and large facilities. A vacuum valve is used as a component of the switchgear. The interior of the vacuum valve is maintained in a constant insulating state (also called a vacuum state) by an insulating container, and a pair of electrodes are housed inside the insulating container so that they can be connected and disconnected. By connecting and disconnecting the pair of electrodes, a fault current can be interrupted or a load current can be connected and disconnected, ensuring a stable supply of power from the switchgear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 140674 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-282923 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-216210 [Patent Document 4] Special Publication No. 62-45654 [Patent Document 5] Japanese Patent Application Publication No. 2023-154158 Summary of the Invention [Problem to be solved by the invention]

[0004] The insulating container has a hollow structure, and both openings of the insulating container are sealed with a metal sealing member. For example, the sealing method involves metallizing the end surface of the insulating container that extends to surround the opening (i.e., converting a non-metallic surface into a metal film), and then joining (welding) the metallized end surface of the insulating container and the outer edge of the sealing member with an adhesive that uses silver solder.

[0005] At this time, at the joint where the end face of the insulating container and the outer edge of the sealing material are joined, a boundary, i.e., a triple junction (also called a triple junction), is formed where the insulating material, the metal material, and the gas (vacuum, air) are adjacent to each other.

[0006] The electric field strength at the triple junction is relatively high compared to the entire vacuum interrupter, which can easily become the starting point for dielectric breakdown.

[0007] Furthermore, it is difficult to maintain a consistent finished shape when metallizing the end surface of the insulating container, and variations in the finished shape can occur. In this case, depending on the degree of variation, it can become difficult to maintain or improve the insulating performance of the vacuum interrupter.

[0008] Conventionally, to solve these problems, for example, the end surface of the insulating container near the triple junction is processed and a metal member is embedded there, thereby alleviating the electric field strength of the triple junction.

[0009] However, the material of the insulating container (e.g., alumina ceramic) is hard and brittle, making it difficult to process the end surface of the insulating container. This increases the time and effort required for processing, which in turn increases the manufacturing cost of the vacuum interrupter.

[0010] Therefore, there is a need for a technology that can reduce the electric field strength of the triple junction, even if there is variation in the finished shape of the metallization process, in other words, without improving the metallization process itself, that is, while using the existing metallization process as is.

[0011] An object of the present invention is to provide a low-cost vacuum interrupter with excellent insulation performance that can reduce the electric field strength of a triple junction while utilizing existing metallization processes as they are. [Means for solving the problem]

[0012] According to one embodiment, the insulating container includes a non-metallic insulating container having a hollow structure with an opening and an end face extending to surround the opening, a metallic sealing member having an outer edge that can be positioned opposite the end face of the insulating container so as to close the opening of the insulating container, and a joining means for joining the sealing member to the insulating container, wherein the end face of the insulating container is provided with an embedding portion into which at least a portion of the entire outer edge of the sealing member can be embedded, and the embedding portion is configured by recessing the end face into a concave shape, and when the sealing member is joined to the insulating container, at least a portion of the entire outer edge of the sealing member is maintained embedded in the embedding portion without any gaps via the joining means. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a cross-sectional view showing the internal configuration of a vacuum valve according to one embodiment. [Figure 2] FIG. 4 is an enlarged cross-sectional view showing the internal configuration of the joint portion. [Figure 3] FIG. 10 is a graph showing the relationship between the embedding depth of the sealing material in the joint and the maximum electric field strength. [Figure 4] FIG. 10 is an enlarged cross-sectional view showing the internal configuration of a joint according to a first modified example. [Figure 5] FIG. 10 is a graph showing the relationship between the relative dielectric constant of the embedding member and the maximum electric field intensity in the joint according to the first modified example. [Figure 6] FIG. 10 is a perspective view showing the configuration of a joint according to a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0014] "One embodiment" 1 is a diagram showing the internal structure of a vacuum valve P according to this embodiment. The vacuum valve P has a fixed electrode E1, a movable electrode E2, an insulating container 1 (also called a vacuum container), a fixed sealing member 2, a movable sealing member 3, an airtightness maintaining mechanism 4, an arc shield 5, and a bellows cover 6. The movable electrode E1, the fixed electrode E2, the airtightness maintaining mechanism 4, the arc shield 5, and the bellows cover 6 are housed inside the insulating container 1, which has a hollow structure.

[0015] 1, insulating container 1 is made of an insulating (non-metallic) material such as alumina ceramic and has a hollow cylindrical shape. Fixed sealing member 2 and movable sealing member 3 are made of a metallic material containing stainless steel as a main component, for example.

[0016] As shown in Fig. 1, a hollow cylindrical insulating container 1 is concentric with an imaginary axis Px that defines the center of a vacuum valve P. A vacuum atmosphere is maintained inside the insulating container 1, and a pair of electrodes E1, E2 are housed in this vacuum atmosphere so that they can be brought into contact with and separated from each other.

[0017] Further, when viewed in the direction of the imaginary axis Px, both ends of the insulating container 1 are opened in a circular shape in a plan view. Both openings (fixed-side opening K1 and movable-side opening K2) are covered by a fixed-side sealing member 2 and a movable-side sealing member 3, each of which has a disk shape.

[0018] Specifically, at a fixed-side joint portion 11 described later, the fixed-side sealing member 2 closes one of the fixed-side openings K1 with its outer edge 2e joined to the fixed-side end face S1 of the insulating container 1. In this case, the fixed-side end face S1 of the insulating container 1 extends so as to surround the fixed-side opening K1. The outer edge 2e of the fixed-side sealing member 2 is configured so as to be able to be disposed opposite the fixed-side end face S1 of the insulating container 1.

[0019] Furthermore, at a movable-side joint portion 12 described later, the movable-side sealing member 3 closes the other movable-side opening K2 with its outer edge 3e joined to the movable-side end surface S2 of the insulating container 1. In this case, the movable-side end surface S2 of the insulating container 1 extends so as to surround the movable-side opening K2. The outer edge 3e of the movable-side sealing member 3 is configured so as to be able to be positioned opposite the movable-side end surface S2 of the insulating container 1.

[0020] The arc shield 5 has a hollow cylindrical shape extending along the imaginary axis Px so as to surround the pair of electrodes E1, E2, and is made of a metal material whose main component is, for example, copper or stainless steel. The arc shield 5 is supported by the insulating container 1 so as to house therein a fixed contact 7 of the fixed electrode E1 and a movable contact 9 of the movable electrode E2, which will be described later.

[0021] The fixed electrode E1 and the movable electrode E2 are arranged concentrically around the imaginary axis Px and extend in alignment along the imaginary axis Px. In this state, the fixed electrode E1 and the movable electrode E2 are positioned so as to face each other in parallel.

[0022] The fixed electrode E1 includes a fixed contact 7 and a fixed current-carrying shaft 8. The movable electrode E2 includes a movable contact 9 and a movable current-carrying shaft 10. The fixed contact 7 and the movable contact 9 are disk-shaped and have the same diameter, and are made of an alloy of a current-carrying material such as Cu or Ag with an arc-resistant material such as chromium (Cr), tungsten (W), or tungsten carbide (WC). The fixed current-carrying shaft 8 and the movable current-carrying shaft 10 are cylindrical and have the same diameter, and are made of a highly conductive material (for example, Cu).

[0023] The fixed contact 7 is connected to one end of a fixed current-carrying shaft 8, the other end of which is immovably fixed to the vacuum valve P along the imaginary axis Px via a fixed-side sealing member 2. The movable contact 9 is connected to one end of a movable current-carrying shaft 10, the other end of which is connected to an operating mechanism (not shown) via a movable-side sealing member 3.

[0024] 1, the movable current-carrying shaft 10 is moved along the imaginary axis Px by an operating mechanism (not shown). This causes the movable contact 9 to move in contact with or away from the fixed contact 7. As a result, the vacuum interrupter P can be opened or closed (i.e., the electrodes E1, E2 can be moved in contact with or away from each other).

[0025] Furthermore, an airtightness maintaining mechanism 4 is disposed between the movable current-carrying shaft 10 and the movable-side sealing member 3. The airtightness maintaining mechanism 4 is made of a flexible bellows. The bellows (airtightness maintaining mechanism) 4 is made of a thin metal such as stainless steel. The bellows 4 is shaped like a bellows and is flexible in the direction of the imaginary axis Px, and covers the outside of the movable current-carrying shaft 10 without any gaps.

[0026] One end of the bellows 4 is tightly joined to the movable sealing member 3, and the other end is tightly joined to the movable current-carrying shaft 10. This ensures that the inside of the insulating container 1 is always kept airtight (i.e., vacuum state). As a result, when the vacuum valve P is opened or closed, the atmosphere (air) does not enter the inside of the insulating container 1, even while the movable current-carrying shaft 10 is being moved along the imaginary axis Px.

[0027] Furthermore, a bellows cover 6 is arranged inside the insulating container 1 so as to cover the airtightness maintenance mechanism 4. The bellows cover 6 is made of a metal material whose main component is, for example, copper or stainless steel. As a result, the bellows cover 6 keeps the airtightness maintenance mechanism 4 in a state where it is not directly opposed to the fixed contact 7 and the movable contact 9. As a result, when an arc generated from the electrode surface (arcing area) by arc discharge strikes the airtightness maintenance mechanism 4 during current interruption, a hole in the airtightness maintenance mechanism 4 may be created depending on the magnitude of the strike, thereby preventing the intrusion of air into the insulating container 1.

[0028] In addition, the above-mentioned vacuum valve P is provided with a technology for reducing the electric field strength of the triple junction where the insulating container 1, the sealing members 2, 3, and the installation atmosphere (vacuum, air) of the vacuum valve P are adjacent to each other at each joint 11, 12.

[0029] In this electric field relaxation technique, the same configuration is applied to the joining portions 11, 12, each of which has joining means 13 for joining the sealing members 2, 3 to the insulating container 1 and an embedding portion 14 provided on the end faces S1, S2 of the insulating container 1. The embedding portion 14 is configured so as to be able to embed at least a portion of the entire outer edges 2e, 3e of the sealing members 2, 3.

[0030] Fig. 2 is a diagram showing the arrangement of the joining means 13 and the embedded portion 14 applied to the joining portions 11 and 12. In the example of Fig. 2, the embedded portion 14 is configured to be able to embed the entire outer edges 2e and 3e of the sealing materials 2 and 3. For this reason, the embedded portion 14 extends continuously in the circumferential direction along the end faces S1 and S2 of the insulating container 1 that extend so as to surround the openings K1 and K2.

[0031] 2, the embedded portion 14 is formed by depressing the end faces S1 and S2 of the insulating container 1 in a concave shape in cross section. The direction of depression of the embedded portion 14 may be, for example, such that the insulating container 1 is dug down in parallel from the end faces S1 and S2 along the imaginary axis Px within the range of the end faces S1 and S2 of the insulating container 1 (i.e., within the range not exceeding the thickness of the insulating container 1).

[0032] The embedded portion 14 has an inner surface 14s that is concave in cross section. The contour shape of the inner surface 14s is configured to match (correspond) to the contour shapes of the outer edges 2e, 3e of the sealing materials 2, 3. In FIG. 2, as an example, the outer edges 2e, 3e of the sealing materials 2, 3 are set to have a U-shaped contour shape in cross section. Correspondingly, the contour shape of the inner surface 14s of the embedded portion 14 is also set to be U-shaped in cross section.

[0033] The size (width, area) of the inner surface 14s of the embedded portion 14 is preferably set larger than the size (width, thickness) of the outer edges 2e, 3e of the sealing members 2, 3. This makes it possible to interpose the joining means 13 without any gaps between the outer edges 2e, 3e of the sealing members 2, 3 and the inner surface 14s of the embedded portion 14 when the outer edges 2e, 3e of the sealing members 2, 3 are embedded in the embedded portion 14. As a result, when the sealing members 2, 3 are joined to the insulating container 1, the entire outer edges 2e, 3e of the sealing members 2, 3 are maintained embedded without any gaps in the embedded portion 14 via the joining means 13.

[0034] Furthermore, it is preferable that the joining means 13 is provided in the embedded portion 14 over an area that does not extend beyond the same plane as the end faces S1, S2 of the insulating container 1 (in other words, an area that does not protrude (i.e., does not extend beyond) the end faces S1, S2 of the insulating container 1).

[0035] 2, as an example, the joining means 13 is composed of a metallized layer 13a and a silver brazing layer 13b, which are provided without any gaps along the inner surface 14s of the embedding portion 14. The metallized layer 13a is formed by metalizing the inner surface 14s of the embedding portion 14 (i.e., a process for metalizing a non-metallic surface) to form a metal film on the inner surface 14s. The silver brazing layer 13b joins the sealing members 2, 3 and the insulating container 1 to each other by welding outer edges 2e, 3e of the sealing members 2, 3 embedded in the embedding portion 14 to the metallized layer 13a.

[0036] Here, in the process of forming the metallized layer 13a, for example, an insulating container 1 is prepared in advance with recessed embedded portions 14 formed on the end faces S1 and S2. Next, a molding material containing molybdenum manganese (Mo-Mn) is applied to the embedded portions 14. In this state, a conventional baking process is performed. After this, a nickel (Ni) plating process is performed on the surface of the baked molybdenum manganese layer. As a result, the metallized layer 13a consisting of a molybdenum manganese layer and a nickel (Ni) plating layer is formed into the embedded portions 14.

[0037] At this time, if the metallized layer 13a is formed so as to protrude from the embedded portion 14 (in other words, so as to protrude beyond the same plane as the end faces S1, S2 of the insulating container 1), for example, by performing a conventional polishing process, the metallized layer 13a can be formed only on the embedded portion 14. Thus, the forming range of the metallized layer 13a is set to only the inner surface 14s of the embedded portion 14.

[0038] Next, as a process for forming the silver brazing layer 13b, for example, a plate-shaped silver brazing material is prepared. Subsequently, this plate-shaped silver brazing material is interposed between the outer edges 2e, 3e of the sealing members 2, 3 and the embedded portion 14 having the metallized layer 13a formed on the inner surface 14s. At this time, the outer edges 2e, 3e of the sealing members 2, 3 are aligned and positioned directly above the embedded portion 14. In this state, the existing baking process is performed. This forms the joining means 13 in which the silver brazing layer 13b is laminated on the metallized layer 13a.

[0039] Furthermore, simultaneously with the above-described forming process of the silver brazing layer 13b, the outer edges 2e, 3e of the sealing members 2, 3 inserted into the embedding portion 14 are welded to the metallized layer 13a by the silver brazing layer 13b. As a result, the outer edges 2e, 3e of the sealing members 2, 3 are embedded without gaps in the embedding portion 14 with the joining means 13 (the metallized layer 13a and the silver brazing layer 13b) interposed therebetween.

[0040] At this time, if the silver brazing layer 13b is formed so as to protrude from the embedded portion 14 (in other words, so as to protrude beyond the same plane as the end faces S1, S2 of the insulating container 1), for example, by performing a conventional polishing process, the silver brazing layer 13b can be formed only on the embedded portion 14. Thus, the forming range of the silver brazing layer 13b is set to only the inner surface 14s of the embedded portion 14.

[0041] In this state, the outer edges 2e, 3e of the sealing members 2, 3 are not embedded in direct contact with the embedded portion 14 (inner surface 14s). Therefore, the outer edges 2e, 3e of the sealing members 2, 3 inserted into the embedded portion 14 are welded evenly over their entirety to the metallized layer 13a by the silver brazing layer 13b. As a result, the sealing members 2, 3 and the insulating container 1 are firmly joined to each other.

[0042] In this case, the embedding amount 14t (i.e., embedding depth) of the outer edges 2e, 3e of the sealing materials 2, 3 in the embedded portion 14 can be reduced by embedding them even slightly, as shown in Figure 3, for example, to reduce the electric field strength (i.e., the current value) of the triple junction in current vacuum valves.

[0043] As shown in Figure 2, it is preferable that the embedding depth 14t is determined by the linear distance between the lowest ends of the outer edges 2e, 3e of the sealing members 2, 3 and the end faces S1, S2 of the insulating container 1, taking into account the thickness of the silver solder layer 13b, as viewed in the direction of the imaginary axis Px.

[0044] Figure 3 shows the results of calculations, by electric field analysis, of the maximum electric field strength at the joints 11 and 12 when the embedding depth of the embedding member 16 is changed. In the example of Figure 3, the vertical axis (relative value) is normalized with the current value (=1) being the maximum electric field strength when the embedding depth 14t is set to 0.0 mm.

[0045] 3, it can be seen that the electric field strength decreases as the embedding depth 14t of the outer edges 2e and 3e relative to the embedded portion 14 increases. For example, by setting the embedding depth 14t to 0.5 mm, it is possible to significantly reduce the electric field strength of the triple junction compared to the current value.

[0046] It can be seen that such an electric field relaxation effect tends to saturate when the embedding depth 14t reaches approximately 1.0 mm. Therefore, it is preferable to set the embedding depth 14t of the outer edges 2e, 3e of the sealing materials 2, 3 relative to the embedding portion 14 to 0.5 mm≦14t≦1.0 mm.

[0047] As described above, according to this embodiment, the outer edges 2e, 3e of the sealing materials 2, 3 are embedded without any gaps in the embedded portions 14 recessed and formed in the end faces S1, S2 of the insulating container 1 via the joining means 13. This makes it possible to reduce the electric field strength of the triple junction without being affected by variations in the finished shape of existing metallization processes, in other words, without improving the metallization process itself, that is, by using the existing metallization process as is.

[0048] According to this embodiment, when the outer edges 2e, 3e of the sealing members 2, 3 are embedded in the embedded portion 14, the outer edges 2e, 3e of the sealing members 2, 3 are not in direct contact with the embedded portion 14 (inner surface 14s), but are welded to the metallized layer 13a by the silver brazing layer 13b all over the outer edges 2e, 3e. As a result, the sealing members 2, 3 and the insulating container 1 can be firmly joined to each other.

[0049] According to this embodiment, the joining means 13 (metallized layer 13a, silver solder layer 13b) is provided in the embedded portion 14 over an area that does not extend beyond the same plane as the end faces S1, S2 of the insulating container 1. As a result, the molding area of ​​the joining means 13 is limited to the inner surface 14s of the embedded portion 14. At this time, the joining means 13 does not protrude (i.e., does not extend beyond) the end faces S1, S2 of the insulating container 1. Therefore, the surface near the triple junction is maintained in a flat state without any irregularities. In this state, there are no areas that could become the starting point of dielectric breakdown, and as a result, the electric field strength of the triple junction can be significantly reduced.

[0050] According to this embodiment, when the openings K1, K2 of the insulating container 1 are closed with the sealing members 2, 3, the outer edges 2e, 3e of the sealing members 2, 3 are inserted into the embedded portions 14 formed on the end faces S1, S2 of the insulating container 1. This allows the sealing members 2, 3 to be accurately positioned with respect to the end faces S1, S2 of the insulating container 1 in a short time, easily, and without misalignment. As a result, the manufacturing cost of the vacuum valve P can be reduced while the assembly quality can be significantly improved.

[0051] "First Variation" Fig. 4 is a partial cross-sectional view of the insulating container 1 according to this modification, on the side of the joints 11 and 12. In the example of Fig. 4, the insulating container 1 includes a single insulating container body 15, embedding members 16 respectively connected to both sides of the insulating container body 15, and connecting means 17 connecting the insulating container body 15 and the embedding members 16.

[0052] Both embedding members 16 have the same configuration and form a hollow structure extending from a base end 16a to a tip 16b. The tip 16b of the embedding member 16 has the same configuration as the joints 11 and 12 of the above-described embodiment, and is constructed with end faces S1 and S2 extending to surround the openings K1 and K2, and an embedding portion 14 provided on the end faces S1 and S2.

[0053] The insulating container body 15 has the same hollow structure as the insulating container 1 of the above-described embodiment, and is configured so as to be connectable to the base end 16a of the embedding member 16. The insulating container body 15 and the embedding member 16 are set to have the same diameter and thickness, and when the embedding members 16 are connected to both sides of the insulating container body 15, they form concentric circles centered on the above-described imaginary axis Px.

[0054] The connecting means 17 is made of a non-conductive material and interconnects the base end 16a of the embedding member 16 and the insulating container body 15 (for example, by solid-state bonding in a state that makes it difficult for vacuum leaks to occur). By interposing the non-conductive connecting means 17 between the embedding member 16 and the insulating container body 15, it is possible to prevent the occurrence of triple junctions. In this case, examples of the non-conductive material that can be used include commercially available adhesives made of organic or inorganic materials, and inorganic brazing materials whose main components are iron or copper oxides or glass.

[0055] As an example of the connection method, the embedding member 16 is connected to the insulating container body 15 by the connection means 17 in a state in which the outer edges 2e, 3e of the sealing members 2, 3 are embedded in the embedding portions 14. That is, before connecting the embedding member 16 to the insulating container body 15, first, as in the above-described embodiment, the outer edges 2e, 3e of the sealing members 2, 3 are embedded in the embedding portions 14 of the embedding member 16. Thereafter, the embedding member 16 in a state in which the outer edges 2e, 3e of the sealing members 2, 3 are embedded in the embedding portions 14 is connected to the insulating container body 15 by the connection means 17.

[0056] The material of the embedding member 16 can be set to either the same material as the insulating container body 15 or a different material from the insulating container body 15. For example, when the insulating container body 15 is made of the same material as the insulating container 1 of the above-described embodiment (for example, an insulating (non-metallic) material such as alumina ceramic), the embedding member 16 can be made of either the same material as the insulating container 1 or a different material, selectively.

[0057] In this case, the insulating material of the embedding member 16 may be, for example, a ceramic material with high workability, such as zirconia, silicon nitride, or machinable ceramics, or an epoxy resin, a phenolic resin, or a silicone resin. This makes it possible to easily recess the embedding portion 14 into the end faces S1 and S2 of the embedding member 16.

[0058] Furthermore, when a material other than the insulating materials described above is selectively used as the material for the embedding member 16, ceramics or resin to which a conductive material is added for antistatic purposes may be used. However, in this case, a new triple junction is formed at the connection portion between the embedding member 16 and the insulating container body 15, and it is expected that measures to alleviate the electric field at this portion (for example, measures related to the relative permittivity and volume resistivity, which will be described later) may be required.

[0059] Here, as an example of the electrical properties of the embedding member 16 in the electric field relaxation measures, the relative dielectric constant of the embedding member 16 is set to be larger (higher) than the relative dielectric constant of the insulating container body 15. The dielectric constant is a physical property value that indicates the degree to which dielectric polarization is induced by the charge possessed by a substance. The relative dielectric constant is the relative value of the dielectric constant of a substance with the dielectric constant of a vacuum (which is set to 1) as the reference.

[0060] 5 shows the results of calculations, by electric field analysis, of the maximum electric field strength at the joints 11 and 12 when the relative dielectric constant of the embedding material 16 is changed. In the example of FIG. 5, the embedding depth 14t is set to 0.5 mm, and the vertical axis (relative value) is normalized by the maximum electric field strength when the same material (e.g., alumina ceramic) as that of the existing insulating container 1 is used.

[0061] As is clear from FIG. 5, when the relative dielectric constant of the embedding member 16 is made larger (higher) than the relative dielectric constant of the insulating container body 15, this promotes dielectric polarization, thereby increasing the electric field relaxation effect.

[0062] In this case, in order to promote dielectric polarization (increase the electric field relaxation effect), a high dielectric constant can be obtained by using, as the material for the embedded member 16, dielectric ceramics such as titanium oxide or barium titanate, or a compound resin filled with these as a conductive filler.

[0063] 4, as an example of the electrical properties of the embedding member 16 in the electric field relaxation countermeasure, the volume resistivity of the embedding member 16 is configured to have electrical properties such that the base end 16a is the most difficult for a current to flow through and the current becomes more easily flowing from the base end 16a to the tip 16b. In other words, the volume resistivity of the embedding member 16 is configured to have electrical properties such that the tip 16b is the most difficult for a current to flow through and the current becomes more easily flowing from the tip 16b to the base end 16a.

[0064] In other words, the embedding member 16 is configured to have electrical properties such that the base end 16a has the highest electrical resistance and the electrical resistance decreases from the base end 16a to the tip 16b. In other words, the embedding member 16 is configured to have electrical properties such that the tip 16b has the lowest electrical resistance and the electrical resistance increases from the tip 16b to the base end 16a.

[0065] In this case, the material distribution of the embedding member 16 to achieve the above-mentioned volume resistivity is set, for example, so that the base end 16a side is made of insulating material and the tip end 16b side is made of conductive material, which makes it possible to eliminate points where the volume resistivity changes drastically, and as a result, the occurrence of high electric field points can be suppressed.

[0066] Such a material distribution configuration can be achieved, for example, by mixing the conductive filler into the insulating material of the above-mentioned embedded member 16 (e.g., ceramics such as zirconia, silicon nitride, and machinable ceramics, or epoxy resin, phenolic resin, and silicone resin) while continuously changing the compounding ratio.

[0067] According to this modification, first, the outer edges 2e, 3e of the sealing members 2, 3 are embedded in the embedding member 16 (embedded portion 14), and then the embedding member 16 and the insulating container body 15 are connected to each other by the connecting means 17. As a result, even if a processing error occurs during the recessing processing of the embedding portion 14, for example, only the embedding member 16 needs to be replaced, and there is no need to replace the entire insulating container 1. As a result, it is possible to reduce material waste required for manufacturing the insulating container 1 (embedded member 16, insulating container body 15).

[0068] According to this modification, non-conductive embedding means 17 is used as a method for connecting the embedding member 16 and the insulating container body 15. This makes it possible to easily separate the embedding member 16 from the insulating container body 15. As a result, it is possible to meet the demand, for example, to recycle only the embedding member 16 and reuse the insulating container body 15 as it is.

[0069] The other configurations and effects are the same as those of the above-described embodiment, and therefore the description thereof will be omitted.

[0070] "Second Variant" Fig. 6 is a diagram showing the arrangement of the insulating container 1 and the sealing members 2 and 3 according to this modified example. While the embedded portion 14 according to the above embodiment is assumed to extend continuously in the circumferential direction along the end faces S1 and S2 of the insulating container 1, in the example of Fig. 6, instead, the embedded portion 14 extends intermittently in the circumferential direction along the end faces S1 and S2 of the insulating container 1.

[0071] 6, two embedded portions 14 are provided at equal intervals along the end surfaces S1 and S2 of the insulating container 1 extending to surround the openings K1 and K2. The two embedded portions 14 have the same configuration.

[0072] On the other hand, the sealing members 2, 3 are configured so that a portion of the entire outer edges 2e, 3e can be embedded in the embedded portion 14. As an example, in Figure 6, the outer edges 2e, 3e of the sealing members 2, 3 are provided with two embedded protrusions Pe at equal intervals along the circumferential direction. As a result, when the outer edges 2e, 3e of the sealing members 2, 3 are arranged opposite the end faces S1, S2 of the insulating container 1, the embedded protrusions Pe and the embedded portion 14 are positioned so as to be aligned and face each other when viewed in the direction of the imaginary axis Px.

[0073] Furthermore, the two embedding protrusions Pe are set to a size and contour shape that allows one to be inserted into each of the two embedding portions 14. As a result, similar to the above-described embodiment, the embedding protrusions Pe inserted into the embedding portions 14 can be welded evenly over their entirety to the metallized layer 13a by the silver brazing layer 13b. As a result, the sealing members 2, 3 and the insulating container 1 can be firmly joined to each other.

[0074] The circular openings in the centers of the sealing members 2 and 3 are current-carrying shaft holes Ph for inserting the above-mentioned current-carrying shafts 8 and 10. The other configurations and effects are the same as those of the above-mentioned embodiment, and therefore description thereof will be omitted.

[0075] Although one embodiment of the present invention and several modifications thereof have been described above, these embodiments and modifications are presented as examples and are not intended to limit the scope of the invention. These embodiments and modifications may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0076] P...vacuum valve, Px...imaginary axis, K1...fixed side opening, K2...movable side opening, E1...fixed electrode, E2...movable electrode, 1...insulating container, S1...fixed side end face, S2...movable side end face, 2...fixed side sealing member, 2e...outer edge, 3...movable side sealing member, 3e...outer edge, 4...airtightness maintaining mechanism, 5...arc shield, 6...bellows cover, 7...fixed contact, 8...fixed current-carrying shaft, 9...movable contact, 10...movable current-carrying shaft, 11...fixed side joint, 12...movable side joint, 13...joining means, 13a...metallized layer, 13b...silver solder layer, 14...embedded portion, 14s...inner surface, 14t...embedding amount (embedding depth), 15...insulating container body, 16...embedding member, 16a...base end, 16b...tip, 17...connecting means, Ph...hole for current-carrying shaft, Pe...embedding protrusion.

Claims

1. a non-metallic insulating container having a hollow structure with an opening so as to accommodate a pair of electrodes in a detachable manner, and having an end surface extending to surround the opening; a metal sealing member having an outer edge that can be placed opposite the end surface of the insulating container so as to close the opening of the insulating container; a joining means for joining the sealing member to the insulating container, an embedding portion capable of embedding at least a part of the entire outer edge of the sealing material is provided on the end surface of the insulating container; the embedded portion is configured by depressing the end surface into a concave shape, A vacuum valve in which, when the sealing member is joined to the insulating container, at least a portion of the entire outer edge of the sealing member is maintained embedded in the embedding portion without any gaps via the joining means.

2. 2. The vacuum valve according to claim 1, wherein the joining means is provided in the embedded portion over an area that does not extend beyond the same plane as the end face of the insulating container.

3. the joining means is provided along the inner surface of the embedded portion without any gaps, a metallized layer formed by metallizing the inner surface of the embedded portion to form a metal film on the inner surface; The vacuum valve as described in claim 2, further comprising a silver solder layer that joins the sealing material and the insulating container to each other by welding the outer edge of the sealing material embedded in the embedded portion to the metallized layer.

4. 4. The vacuum valve according to claim 3, wherein the metallized layer and the silver brazing layer are formed only on the inner surface of the embedded portion.

5. The insulating container is a hollow embedded member extending from a base end to a tip end; an insulating container body having a hollow structure that can be connected to the base end of the embedding member; a connecting means for connecting the base end of the embedding member and the insulating container body to each other, The tip of the embedding member is configured with the end surface extending to surround the opening, and the embedding portion provided on the end surface, 2. The vacuum valve according to claim 1, wherein the embedding member is connected to the insulating container body by the connecting means with the outer edge of the sealing member embedded in the embedding portion.

6. 6. The vacuum valve according to claim 5, wherein the material of the embedding member can be set to either the same material as the insulating container body or a material different from the insulating container body.

7. 6. The vacuum interrupter according to claim 5, wherein the dielectric constant of the embedding member is set to be larger than the dielectric constant of the insulating container body.

8. The vacuum valve according to claim 5, wherein the embedded member is configured to have electrical properties such that the base end is the least likely to allow current to flow and the volume resistivity becomes such that the current flows more easily from the base end toward the tip end.

9. 6. The vacuum valve according to claim 5, wherein said connecting means is made of a non-conductive material.

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