JP3235961B2 - Vacuum valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum valve and, more particularly, to a support structure for a cantilever shield having one end supported by an end plate and disposed so as to surround both electrodes.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view showing the structure of a conventional vacuum valve disclosed in, for example, Japanese Patent Publication No. 53-32870. In the figure, reference numeral 1 denotes a cylindrical insulating container made of a highly insulating member such as alumina ceramics, for example.
Are end plates brazed at both ends of the insulating container 1 with a brazing material such as silver brazing, and have insertion holes 2a, 3
a is formed. Reference numeral 4 denotes a fixed electrode rod which is inserted through the insertion hole 2a of the end plate 2 and is hermetically joined to the end plate 2.

Reference numeral 5 denotes a movable electrode rod which is inserted through the insertion hole 3a of the end plate 3 and is hermetically joined to the end plate 3 via a bellows 6, and 7 and 8 denote a fixed electrode rod 4 and a movable electrode rod 5 respectively. A pair of electrodes 9 are fixed to the front ends of the pair of electrodes, respectively, and a cantilever shield 9 is supported at one end by the end plate 3 and disposed at the other end so as to surround the electrodes 7 and 8. Then, the closed container 1 is formed by the insulating container 1, the both end plates 2, 3 and the bellows 6.
0.

[0004] Next, a method of manufacturing the conventional vacuum valve configured as described above will be described. First, assembling is performed in a partial manner. A fixed-side subassembly including the end plate 2, the fixed electrode rods 4 and the electrodes 7, and a movable-side subassembly including the end plate 3, the movable electrode rods 5 and the electrodes 8 are provided. Assembled by brazing in a non-oxidizing atmosphere. When the partial brazing assembly is completed in this way, visual inspections such as insufficient melting of the brazing material, repelling of the brazing material, insufficient brazing and the like are performed on all the parts, thereby improving reliability.

Next, one end of a cantilever shield 9 is fixed to the upper surface of the plate end 3 of the movable subassembly by brazing. In the final sealing assembly of the vacuum valve, a brazing material is interposed between the end plate 2 of the fixed-side sub-assembly and the end plate 3 of the movable-side sub-assembly and both end surfaces of the insulating container 1, and the inside of the vacuum furnace is set. 40
After baking at a high temperature of 0 ° C. to 600 ° C. and performing sufficient degassing, the temperature is raised to the brazing temperature, the brazing material is melted and hermetically sealed, and the final sealing brazing portion is inspected. The vacuum valve is completed.

[0006]

Since the conventional vacuum valve is constructed and manufactured as described above, the visual inspection of the brazing portion is required, and the partial assembling process, the brazing process of the cantilever shield, and the final sealing are required. There is a problem that three brazing processes of a stop assembly process are required, which requires a manufacturing cost and a construction period. Also, if the brazing step of the cantilever shield is eliminated and the cantilever shield 9 is brazed at the same time in the partial assembling step, a visual inspection of the brazing portion inside the cantilever shield 9 cannot be performed, so it is necessary to perform a leak test. As a result, there is a problem that the leak test requires a lot of work, and the reliability is reduced because the brazing flow cannot be sufficiently confirmed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a structure in which the brazing state of a cantilever shield can be visually observed so that the cantilever shield can be brazed in a final assembly process. Accordingly, it is an object of the present invention to provide a vacuum valve capable of reducing manufacturing costs, shortening a construction period, and improving reliability.

[0008]

A vacuum valve according to a first aspect of the present invention comprises a cylindrical insulating container, a pair of end plates for closing both ends of the insulating container, an insulating container and both end plates. A pair of electrodes which are housed in a closed container and which can be separated from each other, and a cantilever shield which is disposed so as to surround these electrodes and has one end brazed to one of the two end plates. In the vacuum valve, the joint between the end plate and the cantilever shield is configured such that the leaked portion of the brazing material that melts and leaks is exposed to the outside of the sealed container.

According to a second aspect of the present invention, in the vacuum valve according to the first aspect, the joining portion is formed by bending an end plate and one end of the cantilever shield outward, and is smaller than the end plate. An outer bent edge having a smaller diameter, and a sealing member having a smaller diameter than the outer bent edge and having one end joined to the insulating container is formed by bending the other end side inward. The inner bent edge and the inner bent edge are sequentially stacked, and the end plate, the outer bent edge and the inner bent edge are joined by melting of the brazing material disposed between the respective stacking surfaces. Things.

According to a third aspect of the present invention, in the vacuum valve according to the first aspect, the joining portion is formed by bending an end plate and one end of the cantilever shield outward, and is formed on an outer peripheral portion. The first is formed by bending downward so as to fit with the outer periphery of the end plate.
And an outer bent edge stacked on the end plate, the second bent portion being formed to protrude outward from the lower end of the first locked portion. The other end is joined to the container
And a sealing member whose other end face is locked by the second locking section is sequentially fitted, and the stacking surface between the end plate and the outer bent edge is And it is comprised so that it may join by fusion | melting of the brazing material arrange | positioned between the fitting surfaces of a 1st locking part and a sealing member.

According to a fourth aspect of the present invention, in the vacuum valve according to the first aspect, the joining portion is formed by a step formed on the surface of the end plate along the outer periphery and an inner peripheral surface of the step. One end of the fitted cantilever shield is bent outward to form a diameter larger than the end plate, and has an outer bent portion having a sealing portion projecting upward at the outer peripheral end and joined to the insulating container. The edges are stacked and joined by melting a brazing material disposed between the stacked surfaces of the step portion and the outwardly bent edge.

According to a fifth aspect of the present invention, in the vacuum valve according to the first aspect, the joint portion is formed by connecting an end plate having a hole of a predetermined size formed in an outer edge portion to one end of the cantilever shield. The holes are closed by stacking the outwardly bent edges formed by bending outwards, and the melting of the brazing material disposed between the stacking surfaces of the end plates and the outwardly bent edges. It is constituted so that it may be joined by.

According to a sixth aspect of the present invention, in the vacuum valve according to the first aspect, the joining portion is bent outward at one end of the end plate and the cantilever shield to have the same diameter as the end plate. An outer bent edge that is formed and stacked with the end plate is formed so that one end can be fitted to the outer periphery of the end plate and the outer bent edge at the other end side of the sealing member joined to the insulating container. It is configured to be supported by a stepped portion and to be joined by melting a brazing material disposed between the stacked surfaces of the end plate and the outwardly bent edge.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a sectional view showing a configuration of a vacuum valve according to Embodiment 1 of the present invention, and FIG. 2 is an exploded view showing a partially assembled state of the vacuum valve in FIG. In the figure, reference numeral 11 denotes a cylindrical insulating container made of a highly insulating material such as alumina ceramic, and reference numeral 12 denotes a brazing material 13 such as silver brazing so as to close one end of the insulating container 11. In the first end plate thus formed, an insertion hole 12a is formed in the center portion, and the thermal expansion coefficient is an Fe-Ni-Co alloy or an Fe-Ni alloy close to that of alumina ceramics. Therefore, a material such as a Cu-Ni alloy, which reduces residual stress, is used.

Reference numeral 14 denotes a fixed electrode rod which is inserted through the insertion hole 12a of the first end plate 12 and is air-tightly joined to the first end plate 12. Reference numeral 15 denotes a protruding portion 15a at an outer peripheral end and a center portion 15a. A second end plate in which the insertion holes 15b are respectively formed, 16 is a movable electrode rod inserted through the insertion hole 15b of the second end plate 15, and 17 is an insertion of one end of the second end plate 15. Hole 15b
Bellows 18 and 19 are hermetically joined to the movable electrode bar 16 at the inner periphery and the other end, respectively. A pair of electrodes 18 and 19 are fixed to the ends of the fixed electrode bar 14 and the movable electrode bar 16 so as to face each other.

Reference numeral 20 denotes an outer bent edge formed on one end of the second end plate 15 and stacked on the second end plate 15 so as to fit with the protruding portion 15a. A cantilever shield disposed so as to surround both electrodes 18 and 19 with a cylindrical portion 20b formed on the side of the outer end, the outer bent edge 20a and the second end plate 1
5 are joined by melting the brazing material 13 disposed between the stacking surfaces of the brazing material 5. 21 is an outer bent edge 20 of the cantilever shield 20
a is formed in a cylindrical shape having a diameter smaller than that of the insulating container 11.
A sealing member having an inwardly bent edge formed by being bent inwardly on the other end side and stacked on the outwardly bent edge 20a. The same metal material as described above is used, and is joined by melting the brazing material 13 disposed between the stacked surfaces of the outer bent edge 20a and the inner bent edge 21a. The insulating container 11, the first and second end plates 12, 15, the bellows 17, and the sealing member 21 constitute a closed container 22.

Next, a method of manufacturing the vacuum valve according to the first embodiment configured as described above will be described with reference to FIG. First, partial assembly is performed in the same manner as in the conventional case, and the first end plate 12, the fixed-side sub-assembly 23 including the fixed electrode rods 14 and the electrodes 18, and the second end plate 15,
The movable side subassembly 24 including the movable electrode rod 16, the bellows 17 and the electrode 19 is assembled by brazing in a non-oxidizing atmosphere. Then, on the second end plate 15 of the movable side subassembly 24, the cantilever shield 20, the sealing member 2
1. Stacked in the order of the insulating container 11, cover the first end plate 12 of the fixed-side subassembly 23 from above, place the brazing material 13 between each member, and then in a vacuum furnace at 400 ° C. 60
Baking is performed at a high temperature of 0 ° C. to perform sufficient degassing, and then the temperature is raised to the brazing temperature to melt the brazing material 13 to perform hermetic sealing, and inspect the final sealing brazing portion. The vacuum valve is completed.

As described above, according to the first embodiment, the inner bent edge 21a of the sealing member 21 to be stacked and joined, the outer bent edge 20a of the cantilever shield 20, and the second end are provided. Since the respective outer diameters are gradually increased in the order of the plate 15, the state in which the brazing material 13 disposed between the respective stacking surfaces is melted and leaks to the outer peripheral side can be visually observed from the outside of the closed container 22. Therefore, the brazing process of the cantilever shield 20 can be performed simultaneously with the final sealing and assembling process, and can be completed in two processes of the partial assembling process, thereby reducing the manufacturing cost, shortening the construction period and improving reliability. Improvement can be achieved.

Embodiment 2 FIG. 3 is a sectional view showing a configuration of a vacuum valve according to Embodiment 2 of the present invention. In the figure, the same parts as those in the first embodiment shown in FIG. Reference numeral 25 denotes a central portion where the movable electrode rod 16 is inserted and inserted,
2nd end plate in which the insertion hole 25a to which
6 is an outer bent edge 26 formed by bending outward on one end side.
a, a first locking portion 26b formed by bending downward on the outer peripheral portion of the outer bent edge 26a so as to fit with the outer periphery of the second end plate 26, and the first locking portion It has a second locking portion 26c formed to protrude outward from the lower end of the portion 26b, and is disposed so as to surround both electrodes 18 and 19 by a cylindrical portion 26d formed on the other end side. It is a cantilever shield.

Reference numeral 27 denotes a sealing member having one end joined to the insulating container 11 and the other end fitted to the first locking portion 26b of the cantilever shield 26 and locked to the third locking portion 26c. , Second
Between the stacking surfaces of the end plate 25 and the outer bent edge 26a of the cantilever shield 26, and the first locking portion 26b and the sealing member 27
A brazing material (not shown) is arranged between the fitting surfaces of the members, and the members are joined by being melted. Then, the insulating container 11, the first and second end plates 12, 2
5, the bellows 17 and the sealing member 27 constitute a closed container 28.

As described above, according to the second embodiment, the first locking portion 26 b of the cantilever shield 26 is fitted to the outer periphery of the second end plate 25, and the other end of the sealing member 27. Is locked by the second locking portion 26c of the cantilever shield 26, and the end of each fitting surface and locking surface is exposed to the outside of the closed container 28. The melting of the brazing material disposed between the stacked surfaces of the outer bent edge 26a of the cantilever shield 26 and the outer bent edge 26a is in a state of leakage from the end of the fitting surface and the first of the cantilever shield 26 is melted. In the case of the first embodiment, the melting of the brazing material disposed between the engagement surfaces of the engagement portions 26b and the sealing members 27 can be visually observed in a state of leakage from the ends of the engagement surfaces. Similarly, the brazing process of the cantilever shield 26 is performed simultaneously with the final sealing assembly,
It is possible to perform only two steps, that is, a partial assembling step, and it is possible to reduce manufacturing costs, shorten a construction period, and improve reliability.

Embodiment 3 FIG. FIG. 4 is a sectional view showing a configuration of a vacuum valve according to Embodiment 3 of the present invention. In the figure, the same parts as those in the first and second embodiments are denoted by the same reference numerals, and description thereof will be omitted. Reference numeral 29 denotes a movable electrode rod 16 penetratingly inserted into the center, and a bellows 17.
An insertion hole 29a is formed at the outer peripheral portion.
b is the formed second end plate.

Reference numeral 30 denotes a cylindrical portion 30a which is disposed on one end side so as to surround the electrodes 18 and 19 and is fitted to the inner peripheral surface of the step portion 29b of the second end plate 29; The second end plate 29 is bent outward from the lower end of the cylindrical portion 30a.
An outer bent edge 30b stacked on the upper surface of the stepped portion 29b and having a diameter larger than that of the second end plate 29, and an insulating container protruding upward from the outer peripheral end of the outer bent edge 30b. 11
And a brazing material disposed between the stepped portion 29b of the second end plate 29 and the outer bent edge 30b of the cantilever shield 30. It is joined to the second end plate 29 by melting. Then, the insulating container 11, the first and second end plates 12, 29, the bellows 17, the outer bent edge 30b of the cantilever shield 30,
The sealed container 31 is constituted by the sealing portion 30c.

As described above, according to the third embodiment, the outer bent edge 30b of the cantilever shield 30 is formed to have a larger diameter than the second end plate 29 to be stacked. Since the end is exposed to the outside of the closed container 31, the melting of the brazing material disposed between the stacking surfaces can be visually observed in a state of leakage from the end of the stacking surface. As in the first and second embodiments, the brazing process of the cantilever shield 30 can be performed simultaneously with the final sealing assembly, and can be completed in two processes, the partial assembly process, and the manufacturing cost can be reduced. The construction period can be shortened and the reliability can be improved, and the number of parts and hermetically sealed portions can be reduced, so that the assemblability can be improved.

Embodiment 4 FIG. 5 is a sectional view showing a configuration of a vacuum valve according to Embodiment 4 of the present invention. In the figure, the same parts as those in the first to third embodiments are denoted by the same reference numerals, and the description is omitted. Reference numeral 32 denotes a central part where the movable electrode rod 16 penetrates and is inserted.
The second end plate is formed with an insertion hole 32a formed with a hole 32b having a predetermined size at the outer edge and a sealing portion 32c projecting upward and joined to the insulating container 11. .

Reference numeral 33 denotes a cylindrical portion 33a provided on one end side so as to surround the electrodes 18 and 19, and a cylindrical portion 33a on the other end side bent outward from the lower end of the cylindrical portion 33a. A cantilever shield in which outer bent edges 33b stacked on the upper surface of the second end plate 32 and fitted with the sealing portions 32c are formed, respectively, by melting a brazing material disposed between the stacked surfaces. Second end plate 32
Joined to. The insulating container 11, the first and second end plates 12, 32, and the bellows 17 constitute a closed container 34.

As described above, according to the fourth embodiment, the second bent edge 33b of the cantilever shield 33 is stacked.
A hole 32b is formed in the end plate 32 so that a part of the stacking surface is exposed to the outside of the closed container 34, so that the brazing material disposed between the stacking surfaces melts, In the third embodiment, it is possible to visually check in a state of leakage from the end of the third embodiment.
As in the case of (1), the brazing process of the cantilever shield 32 can be performed simultaneously with the final sealing and assembling, and can be completed in two processes of the partial assembling process, thereby reducing the manufacturing cost, shortening the construction period and improving reliability. And the number of parts and hermetically sealed locations can be reduced to improve assemblability.

Embodiment 5 FIG. 6 is a sectional view showing a configuration of a vacuum valve according to Embodiment 5 of the present invention. In the figure, the same parts as those in each of the first to fourth embodiments are denoted by the same reference numerals, and description thereof will be omitted. Reference numeral 35 denotes a central portion through which the movable electrode rod 16 penetrates and is inserted.
A second end plate is formed with an insertion hole 35a for joining with the insulating container 11, and a sealing portion 35b projecting upward and joined to the insulating container 11 is formed on the outer peripheral portion. Is a first end plate in which an insertion hole 36a to be penetrated and joined is formed.

The first end plate 36 is bent outward at one end to have the same diameter as the first end plate 36. An outer bent edge 37a stacked on the first end plate 36 has The two electrodes 18, 1 on the end side
9 is a cantilevered shield formed with a cylindrical portion 37b disposed so as to surround the insulating container 11 at the lower end thereof.
A first end plate 36 and a stepped portion 38a that is fitted and supported on each outer peripheral portion of the outwardly bent edge 37a of the cantilever shield 37 at the upper end. End plate 36
Are joined by melting of the brazing material disposed between the stacked surfaces of the outer bent edge 37a and the outer bent edge 37a. The insulating container 11, the bellows 17, the first and second end plates 36 and 35, and the sealing member 38 constitute a closed container 39.

As described above, according to the fifth embodiment, the first end plate 36 on which the brazing material is disposed and the stacking surface of the outwardly bent edge 37a of the cantilever shield 37, Each outer periphery of the end plate 36 and the outer bent edge 37a and the sealing member 38
And the end of the fitting surface is exposed to the outside of the closed container 39, so that the brazing material disposed between the stacking surfaces does not melt. In the same manner as in the fourth embodiment, the brazing step of the cantilever shield 33 is performed simultaneously with the final sealing assembly, so that the part can be partially assembled. It is possible to reduce the manufacturing cost, shorten the construction period and improve the reliability, and improve the assemblability by reducing the number of hermetically sealed parts. become.

[0031]

As described above, according to the first aspect of the present invention, a cylindrical insulating container, a pair of end plates for closing both ends of the insulating container, an insulating container and both end plates are formed. A vacuum including a pair of electrodes housed in a sealed container and capable of being separated from and separated from each other, and a cantilever shield disposed so as to surround these electrodes and having one end brazed to one of the two end plates. In the valve, the joint between the end plate and the cantilever shield is configured so that the leaked part of the brazing material that melts and leaks is exposed outside the sealed container, reducing manufacturing costs, shortening the construction period and reliability. Can provide a vacuum valve that can be improved.

According to a second aspect of the present invention, in the first aspect, the joining portion is formed by bending the end plate and one end of the cantilever shield outwardly, and has a smaller diameter than the end plate. An outer bent edge having a diameter smaller than the outer bent edge and an inner end formed by bending the other end of the sealing member having one end joined to the insulating container inward. Since the bent edges are sequentially stacked, and the end plates, the outer bent edges and the inner bent edges are configured to be joined by melting of the brazing material disposed between the respective stacking surfaces, It is possible to provide a vacuum valve capable of reducing manufacturing cost, shortening a construction period, and improving reliability.

According to a third aspect of the present invention, in the first aspect, the joining portion is formed by bending the end plate and one end of the cantilever shield outward, and the end plate is formed on the outer peripheral portion. A first locking portion formed by bending downward so as to fit with the outer periphery of the first locking portion, and a second locking portion formed by projecting outward from a lower end of the first locking portion. An outer bent edge stacked on the end plate, one end joined to the insulating container, the other end fitted to the first locking portion, and the other end surface locked to the second locking portion. The sealing members are sequentially fitted, and will be disposed between the stacking surfaces of the end plates and the outwardly bent edges and between the fitting surfaces of the first locking portions and the sealing members. Since it is configured to be joined by melting the materials, it is possible to provide a vacuum valve capable of reducing the manufacturing cost, shortening the construction period and improving the reliability.

According to a fourth aspect of the present invention, in the first aspect, the joining portion is fitted to a step formed along the outer periphery on the surface of the end plate and an inner peripheral surface of the step. One end of the cantilevered shield is bent outward to form a larger diameter than the end plate, and has an outer bent edge that has a sealing portion that projects upward at the outer peripheral end and is joined to the insulating container. Are stacked and joined by melting the brazing material placed between the stacking surfaces of the step and the outward bent edge, so that the manufacturing cost is reduced, the construction period is shortened, and the reliability is reduced. It is possible to provide a vacuum valve capable of improving the assemblage as well as improving the vacuum valve.

According to a fifth aspect of the present invention, in the first aspect, the joint portion is formed by forming an end plate having a hole of a predetermined size in an outer edge portion and an end of the cantilever shield outward. The hole is closed by stacking the outer bent edge formed by folding into a hole, and joining by melting of the brazing material arranged between the stacking surfaces of the end plate and the outer bent edge As a result, it is possible to provide a vacuum valve capable of not only reducing the manufacturing cost, shortening the construction period and improving the reliability but also improving the assemblability.

According to a sixth aspect of the present invention, in the first aspect, the joint portion is formed to have the same diameter as the end plate by bending the end plate and one end of the cantilever shield outward. A step formed so that the outer bent edge stacked with the end plate can be fitted to the outer periphery of the end plate and the outer bent edge at the other end of the sealing member having one end joined to the insulating container. In addition to being supported by the part, it is configured to be joined by melting the brazing material placed between the stacking surface of the end plate and the outward bent edge, so that manufacturing cost is reduced, construction time is shortened, and reliability is reduced. It is possible to provide a vacuum valve capable of improving not only the assemblage but also the assemblability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a vacuum valve according to Embodiment 1 of the present invention.

FIG. 2 is an exploded view showing a partially assembled state of the vacuum valve in FIG.

FIG. 3 is a sectional view showing a configuration of a vacuum valve according to Embodiment 2 of the present invention.

FIG. 4 is a sectional view showing a configuration of a vacuum valve according to Embodiment 3 of the present invention.

FIG. 5 is a cross-sectional view showing a configuration of a vacuum valve according to Embodiment 4 of the present invention.

FIG. 6 is a sectional view showing a configuration of a vacuum valve according to a fifth embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a configuration of a conventional vacuum valve.

[Explanation of symbols]

11 insulated container, 12, 36 first end plate, 13 brazing material, 15, 25, 29, 32, 35 second end plate, 1
8, 19 electrodes, 20, 26, 30, 33, 37 cantilever shields, 20a, 26a, 30b, 33b, 37a
Outer bent edge, 21, 27, 38 Sealing member, 21a
Inward bent edge, 22, 28, 31, 34, 39 sealed container, 23 fixed-side subassembly, 24 movable-side subassembly, 26b first locking portion, 26c second locking portion, 2
9a, 38b Stepped portion, 30a, 33a, 37b Cylindrical portion, 30c, 32c Sealing portion.

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01H 33/66

Claims (6)

(57) [Claims] 1. A cylindrical insulating container, a pair of end plates for closing both ends of the insulating container, and a pair of electrodes which are housed in a closed container formed by the insulating container and the both end plates and which can be separated from each other. And a cantilever shield provided so as to surround these two electrodes and one end of which is brazed to one of the end plates. The vacuum valve is characterized in that the part is configured such that a leak part of the brazing material that melts and leaks is exposed to the outside of the closed container. 2. The joining portion includes an end plate, an outer bent edge formed by bending one end of the cantilever shield outward, and having a smaller diameter than the end plate. An inner bent edge formed by bending the other end of the sealing member having a diameter smaller than the edge and having one end joined to the insulating container inward is sequentially stacked, and The vacuum valve according to claim 1, wherein the plate, the outer bent edge and the inner bent edge are joined by melting a brazing material disposed between the respective stacking surfaces. 3. The joining portion is formed by bending an end plate and one end side of a cantilever shield outward, and bending the outer peripheral portion downward so as to fit with the outer periphery of the end plate. An outer bent portion having a first locking portion formed and a second locking portion projecting outward from a lower end of the first locking portion and stacked on the end plate; The edge and a sealing member, one end of which is joined to the insulating container and the other end of which is fitted to the first locking portion and the other end surface of which is locked to the second locking portion, are sequentially fitted. Between the stacking surface of the end plate and the outwardly bent edge and the first
2. The vacuum valve according to claim 1, wherein the brazing material is joined by melting of a brazing material disposed between the engaging portion of the sealing member and the fitting surface of the sealing member. 4. The joint portion is formed by bending a step formed on the surface of the end plate along the outer periphery and one end of a cantilever shield fitted to the inner peripheral surface of the step outward. The outer bent edge having a sealing portion which is formed to have a diameter larger than that of the end plate and protrudes upward from the outer peripheral end and is joined to the insulating container is stacked, and the stepped portion and the outer folded edge are stacked. 2. The vacuum valve according to claim 1, wherein the joining is performed by melting a brazing material disposed between the stacking surface and the curved edge. 5. A joining portion comprising: an end plate having a hole of a predetermined size formed in an outer edge portion; and an outer bent edge formed by bending one end of a cantilever shield outward. 2. The method according to claim 1, wherein the holes are closed by stacking, and are joined by melting a brazing material disposed between stacking surfaces of the end plate and the outwardly bent edge. Vacuum valve. 6. A joint portion comprising: an end plate; and an outer bent edge formed by bending one end of the cantilever shield outward to have the same diameter as the end plate and stacked with the end plate. Is supported on the other end of the sealing member having one end joined to the insulating container by a step formed so as to be fitted to the outer periphery of the end plate and the outer bent edge, and the end plate and the outer side are supported. 2. The vacuum valve according to claim 1, wherein the joining is performed by melting a brazing material disposed between the stacking surface and the bent edge.