JPH0973847A - Vacuum bulb - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate work for fixingly attaching reinforcement members or reinforcement plate parts by silver brazing or the like and to improve breaking characteristics and restriking characteristics in a reduced size. SOLUTION: There is provided a reinforcement plate 17 a part of which is fixedly attached to a peripheral part of a fixingly-attaching part 16a of a reinforcement member 16 and which is arranged in a recessed part 23e of a coil electrode 23. A surface layer, of the whole surface excepting the fixingly- attaching part or of a part of the surface, of at least one of the reinforcement member 16 and/or the reinforcement plate 17 is composed of a film of oxide of at least one element of constituents of the reinforcement member 16 and/or the reinforcement plate 17.

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 improvement of a reinforcing member and a reinforcing plate portion of an electrode structure.

[0002]

2. Description of the Related Art A vacuum valve having a coil electrode for applying a magnetic field (for example, a current-carrying axis direction) to a contact surface has already been put into practical use. FIG. 3 shows a typical configuration example thereof.
In the figure, the vacuum container 1 is constructed by sealing the openings at both ends of the insulating container 2 with end plates 3a and 3b. A fixed electrode 4 and a movable electrode 5 are arranged in the vacuum container 1 so as to face each other. The fixed electrode 4 is attached to the end of the fixed energizing shaft 6 which penetrates the end plate 3a. The movable electrode 5 is the end plate 3
It is attached to the end of the movable energizing shaft 8 which penetrates b through the bellows 7. The movable energizing shaft 8 is moved in the axial direction by an operation mechanism (not shown), and the fixed electrode 4 and the movable electrode 5 are brought into contact with and separated from each other to turn on / off a current. Further, the movable energizing shaft 8 penetrates the end plate 3b through the bellows 7 so that the vacuum container 1 is kept airtight and is movable in the axial direction. The shield 9 is provided so as to cover the periphery of both electrodes 4 and 5 and prevents the metal vapor generated at the time of current interruption from directly adhering to the insulating container 2 and deteriorating the insulating property.

Next, the electrode structure will be further described with reference to each reference example. Reference example A will be described with reference to FIG. FIG.
(B) is a BB line sectional view of the same figure (a). The fixed electrode 4 and the movable electrode 5 are configured to generate an axial magnetic field when energized as described above. The fixed electrode 4 includes a main electrode 10, a coil electrode 11, and a reinforcing member 12 provided between the main electrode 10 and the coil electrode 11. The main electrode 10 and the coil electrode 11 are made of copper (1.
7 μΩcm), and the reinforcing member 12 is made of stainless steel (100 to 150 μΩcm) having much higher resistance than copper.
The resistance difference of about 50 to 100 times exists between them. The reinforcing member 12 is formed with a fixing portion 12a that is fixed to the coil electrode 11 and a flange portion 12b that is fixed to the inner surface of the main electrode 10 by abutting. The movable electrode 5 is also provided with a similar reinforcing member 15 between the main electrode 13 and the coil electrode 14.

However, in the above electrode structure, the reinforcing member 12 (15) is fixed to the coil electrode 11 (14) by the fixing portion 12a (15a) and the flange portion 12b.
It is fixed to the main electrode 10 (13) at (15b). Therefore, even if the electric resistance value of the reinforcing member 12 (15) is much larger than those of the main electrode 10 (13) and the coil electrode 11 (14), one of the currents flowing through the electrode 4 (5) is reduced. The part is diverted to the reinforcing member 12 (15). As a result, the current flowing through the coil electrode 11 (14) is reduced accordingly. As shown in FIG. 4 (b), the coil electrode 11 (14) has arcuate portions 11a, 11b, 11c, 11 concentric with the fixed energizing shaft 6 (8) and forming a current path in the circumferential direction.
d (14a, 14b, 14c, 14d) are provided, and the electric current in the circumferential direction flowing through the arc portion stabilizes the vacuum arc generated between the electrodes 4 and 5 to enable large current interruption. . Therefore, the coil electrode 1 of the fixed electrode 4
1. When the current flowing through the coil electrode 14 of the movable electrode 5 decreases, the strength of the magnetic field generated between the electrodes 4 and 5 decreases,
The stability of the vacuum arc may also be reduced, and the breaking performance may be reduced.

Reference example B will be described. A reinforcing member 12 is provided as a technique for compensating for the concern about the deterioration of the blocking performance as in Reference Example A.
(15) Flange 12b (15b) and main electrode 10
(13) does not adhere to each other but only abuts to reduce the current shunting to the reinforcing member 12 (15) as much as possible to prevent the current flowing through the coil electrode 11 (14) from decreasing. A technology is also used that does not reduce the strength of the magnetic field generated between the two. However, the reinforcing member 12
(15) Flange 12b (15b) and main electrode 10
If (13) is not adhered, deformation may occur when the electrodes 4 and 5 are turned on or off. Therefore, the coil electrode 1
By increasing the thickness of 1 (14), it becomes necessary to increase the mechanical strength, and the size of the main electrode / coil electrode is increased, and the distance between the main electrode / coil electrode is increased. It is also a factor that hinders downsizing and downsizing of a vacuum circuit breaker equipped with this vacuum valve, and a factor of increasing material cost.

Reference example C will be described with reference to FIGS.
FIG. 5B is a plan view of the reinforcing plate 17 in FIG. As a technique for compensating for the concern about deterioration of the blocking performance as in Reference Example A, an electrode having a configuration shown in FIG. 5 has been put into practical use. In FIG. 5, the fixed electrode 4 has a reinforcing member 16
Is disposed between the main electrode 10 and the coil electrode 11, the fixing portion 16a is fixed to the coil electrode 11, and the flange portion 16b
Is in contact with the main electrode 10. Further, in the movable electrode 5, a reinforcing member 18 is arranged between the main electrode 13 and the coil electrode 14, a fixing portion 18 a is fixed to the coil electrode 14, and a flange portion 18 b is in contact with the main electrode 13. Reinforcing member 16
(18) Flange 16b (18b) and coil electrode 1
The reinforcing plate 17 is inserted between 1 (14). The reinforcing plate 17 includes arc portions 11a to 11 of the coil electrode 11 (14).
The outer circumference has a size larger than the inner diameter of d (14a to 14d). In the center, the fixing portion 16 of the reinforcing member 16 (18)
a (18a) penetrates, and the flange portion 16b (18
A hole 17a having a size smaller than the outer diameter of b) is formed. The main electrode 10 (13) and the coil electrode 11 (1
4) connecting portions 10a, 10b, 10c, 10d (13
a, 13b, 13c, 13d) (see FIG. 4B) are provided with notches 17b, 17c, 17d, 17e. Therefore, the reference example C has the following advantages. (A) When an external force in the compression direction acts between the electrodes 4 and 5 (when the breaker is turned on), the main electrode 10 (13) is in contact with the reinforcing member 16 (18), and thus the coil electrode 11 (14) does not deform in the compression direction (in Reference Example B, it does). (B) Conversely, when an external force in the pulling direction acts between both electrodes 4 and 5 (when the breaker is opened),
Since the coil electrode 11 (14) is in contact with the reinforcing plate 17 and the reinforcing plate 17 is in contact with the reinforcing member 16 (18),
The coil electrode 11 (14) is not deformed in the pulling direction (it is deformed in Reference Example B).

Here, for example, in the valve assembly in the case of Reference Example C, in order to improve the silver brazing property, the reinforcing member 16 is plated with Ni at predetermined places as necessary.
(18) is prepared and the end portion 1 of the reinforcing member 16 (18) is prepared.
6c (18c) (see FIG. 6) and the end of the fixed energizing shaft 6 (end of the movable energizing shaft 8) are fixed by silver brazing (silver brazing part 1). At the same time as this step, the reinforcing member 16 (1
8) and the coil electrode 11 (14) to the fixed portion 16a (18
In a), it is fixed by silver brazing (silver brazing part 2). There are serious problems in the silver brazing work at these two locations. That is, for example, the reinforcing member 16 (18) and the coil electrode 11 (14) that are insufficient in space are joined, and the reinforcing plate 17 and the coil electrode 11 (14) are joined.
As a result, the silver brazing material flows out to the portions that should not be joined, the deformation preventing effect expected in Reference Example C cannot be obtained, and the breaking characteristics and the re-ignition characteristics are seriously affected. As described above, each of the reference examples A, B, and C has respective advantages, and in reality, the priority request function as a circuit breaker, the manufacturability, the economical efficiency, etc. are appropriately selected based on the criteria.

[0008]

As described above, in the vacuum valve, the main electrode 10 (13) and the coil electrode 11 (1
4), so that the reinforcing member 16 (18) and the reinforcing plate 17 are present between them, an extremely narrow gap portion or a narrow area portion is structurally joined by silver brazing.
Therefore, the silver brazing filler metal may flow out to an unnecessary portion or a harmful place, and a part of the flowing out silver brazing filler metal is short-circuited between the main electrode 10 (13) and the reinforcing member 16 (18) ( (Electrical connection), a short circuit (electrical connection) between the reinforcing member 16 (18) and the reinforcing plate 17, and a short circuit (electrical connection) between the reinforcing plate 17 and the coil electrode 11 (14), resulting in Between the main electrode 10 (13) and the coil electrode 11 (14), the connecting portions 10a, 10b, 10c, 10d of FIG.
A current path that does not pass through (13a, 13b, 13c, 13d) is formed, and the effective current component for generating the magnetic field is reduced, which becomes a factor of lowering the breaking performance. Further, another part of the silver brazing material that has flowed out is also a factor that causes re-ignition by being peeled off or detached by an electric shock at the time of making and breaking. Therefore, the silver brazing material used during assembly is
At a predetermined joining position, that is, the coil electrode 11 (1
4) / between the current-carrying shafts 6 (8) and the reinforcing member 16 (18) of FIG.
It is important that the end portion 16c (18c) / current-carrying shaft 6 (8) is digested only at the joint and does not flow to other portions.

[0009] The present invention has been made in view of the above,
Provided a vacuum valve with a small size, stable cutoff characteristic, and re-ignition characteristic by improving the reinforcing member arranged between the main electrode and the coil electrode and the reinforcing plate to facilitate fixing work by silver brazing etc. The purpose is to do.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 has a structure in which a pair of electrodes is disposed in a vacuum container so as to be contactable and separable, and each of the electrodes. Is a main electrode, a coil electrode which is disposed on the back surface side of the main electrode and generates a magnetic field on the main electrode surface, and a concave portion is provided on a surface facing the main electrode, and a flange portion of the main electrode. A reinforcing member that abuts on the back surface and has a fixing portion at the other end fixed to a concave portion of the coil electrode, and a portion fixed to an outer peripheral portion of the fixing portion of the reinforcing member and arranged in the concave portion of the coil electrode. A vacuum valve provided with a reinforcing plate having one surface abutting against a rear surface of a flange portion of the reinforcing member, wherein at least one surface layer of the reinforcing member and / or the reinforcing plate has a portion other than the fixed portion. The entire surface or part of the surface is the reinforcing member or / At least one of the constituents of the micro reinforcing plate
The gist is that it is composed of an oxide film of one element.
With this configuration, by providing a high resistance oxide film on the entire surface or a part of the surface of the reinforcing member and / or the reinforcing plate excluding the fixed portion, the space between the reinforcing member and the coil electrode is insufficient, and the reinforcing plate and the reinforcing plate are reinforced. Bonding between members by silver brazing or the like is performed only in a necessary portion, and the main electrode and the coil electrode do not come into direct electrical contact with each other. Therefore, the current for generating the magnetic field sufficiently flows through the coil electrode, and it becomes possible to improve the cutoff characteristic and the re-ignition characteristic.

According to a second aspect of the present invention, in the vacuum valve according to the first aspect, the oxide film of at least one element of the constituents of the reinforcing member or / and the reinforcing plate is an oxide containing chromium oxide as a main component. The gist is that it is a film. With this configuration, stability is further increased against heat treatment during assembly of the vacuum valve and mechanical / electrical shock received when the vacuum valve is turned on / off. The oxide film is
Qualitatively, it is desirable to use only chromium oxide, but even if chromium oxide is the main component, the desired action and effect can be obtained.

According to a third aspect of the present invention, in the vacuum valve according to the first aspect, the base material of the reinforcing member and / or the reinforcing plate is made of either martensitic stainless steel or martensitic heat resistant steel. The oxide film of at least one element of the constituents of the reinforcing member or / and the reinforcing plate is an oxide film containing chromium oxide as a main component. With this configuration, the entire surface of the martensitic stainless steel containing chromium as a constituent or the martensitic heat-resistant steel base material is subjected to a treatment such as selective oxidation to remove the reinforcing member or / and the reinforcing plate. An oxide film containing chromium oxide as a main component is formed on a part of the surface.

According to a fourth aspect of the present invention, in the vacuum valve according to the first aspect, the reinforcing member or / and the reinforcing plate has a base material made of martensitic stainless steel or martensitic heat resistant steel. The oxide film of at least one element of the constituents of the reinforcing member and / or the reinforcing plate is chromium oxide. In this configuration, by adjusting the humidity of the oxygen atmosphere at the time of selective oxidation and the pretreatment of the surface of the reinforcing member or / and the reinforcing plate, the oxide film of the surface layer can be made of high quality chromium oxide. .

According to a fifth aspect of the present invention, in the vacuum valve according to the first aspect, the base material of the reinforcing member or / and the reinforcing plate is made of either ferritic stainless steel or ferritic heat resistant steel, The oxide film of at least one element constituting the reinforcing member or / and the reinforcing plate is
The gist is that it is an oxide film containing chromium oxide as a main component. With this configuration, even when a ferritic stainless steel containing chrome as a constituent or a ferritic heat-resistant steel is used as a base material, the fixing portion of the reinforcing member or / and the reinforcing plate can be fixed by performing a treatment such as selective oxidation. An oxide film containing chromium oxide as a main component is formed on the entire surface or a part of the surface excluding it.

According to a sixth aspect of the present invention, in the vacuum valve according to the first aspect, the base material of the reinforcing member or / and the reinforcing plate is made of either ferritic stainless steel or ferritic heat resistant steel, The oxide film of at least one element constituting the reinforcing member or / and the reinforcing plate is
The gist is that it is chromium oxide. In this configuration, similarly to the above, by adjusting the humidity of the oxygen atmosphere at the time of selective oxidation and the pretreatment of the surface of the reinforcing member or / and the reinforcing plate, the oxide film of the surface layer is made of high-quality chromium oxide. It is possible.

According to a seventh aspect of the present invention, in the vacuum valve according to the first aspect, the base material of the reinforcing member and / or the reinforcing plate is made of either austenitic stainless steel or austenitic heat resistant steel. The summary is that the oxide film of at least one element of the constituent components of the reinforcing member and / or the reinforcing plate is an oxide film containing chromium oxide as a main component. With this configuration, even when austenitic stainless steel or austenitic heat-resistant steel containing chromium as a constituent is used as the base material, the reinforcing member or / and the fixing portion of the reinforcing plate can be fixed by performing treatment such as selective oxidation. An oxide film containing chromium oxide as a main component is formed on the entire surface or a part of the surface excluding it.

According to an eighth aspect of the invention, in the vacuum valve according to the first aspect, the base material of the reinforcing member and / or the reinforcing plate is made of either austenitic stainless steel or austenitic heat resistant steel. The gist is that the oxide film of at least one element of the constituent components of the reinforcing member or / and the reinforcing plate is chromium oxide. In this configuration, similarly to the above, by adjusting the humidity of the oxygen atmosphere at the time of selective oxidation and the pretreatment of the surface of the reinforcing member or / and the reinforcing plate, the oxide film of the surface layer is made of high-quality chromium oxide. It is possible.

The invention according to claim 9 is the above-mentioned claim 2,
In the vacuum valve described in 3, 5, or 7, the gist is that at least one of iron oxide, aluminum oxide, silicon oxide, and titanium oxide is present in the oxide film containing chromium oxide as a main component. With this configuration, specifically, even if at least one of iron oxide, aluminum oxide, silicon oxide, and titanium oxide is present in the oxide film, the desired action and effect can be obtained.

According to a tenth aspect of the present invention, in the vacuum valve according to any one of the first to ninth aspects, the chromium oxide or the oxide film containing chromium oxide as a main component is 0.
The gist is to have a thickness of 1 to 50 μm. With this configuration, when the thickness of the oxide film is less than 0.1 μm, the silver brazing material or the like may adhere in a granular form other than the necessary portion when being fixed by silver brazing, etc. to degrade. If it exceeds 50 μm, the adhered silver brazing material and the like may be peeled off and scattered, resulting in deterioration of restriking characteristics and the like. Therefore, the thickness of the oxide film on the surface of the reinforcing member or / and the reinforcing plate is limited to 0.1 to 50 μm.

The invention according to claim 11 is characterized in that the
A pair of electrodes are arranged so that they can come into contact with and separate from each other, and each of the electrodes is provided with a main electrode and a magnetic field on the main electrode surface provided on the back surface side of the main electrode and the main electrode. A coil electrode having a recessed portion on the opposite surface thereof, a flange member abutting the back surface of the main electrode and a fixing portion at the other end fixed to the recessed portion of the coil electrode, and a portion of the reinforcing member. A vacuum valve, comprising: a reinforcing plate fixed to an outer peripheral portion of a fixing portion of a reinforcing member, disposed in a concave portion of the coil electrode, and having a reinforcing plate whose one surface abuts a rear surface of a flange portion of the reinforcing member, At least one surface layer of the reinforcing member and / or the reinforcing plate has a whole surface or a part of the surface excluding the fixed portion formed of a nitride film of at least one element of the constituent components of the reinforcing member and / or the reinforcing plate. What is done is the gist. With this configuration, even if a high-resistance nitride film is used as the surface layer film instead of the oxide film, the same action and effect as those of the invention described in claim 1 can be obtained.

The invention according to claim 12 is the above-mentioned claim 11.
In the vacuum valve described, the nitride coating is 0.1
The gist is to have a thickness of ˜50 μm. With this configuration, even when a nitride coating is used as the surface layer coating, the desired action and effect can be obtained by limiting the thickness of the coating to 0.1 to 50 μm, similarly to the above.

According to a thirteenth aspect of the present invention, there is provided one
A pair of electrodes are arranged so that they can come into contact with and separate from each other, and each of the electrodes is provided with a main electrode and a magnetic field on the main electrode surface provided on the back surface side of the main electrode and the main electrode. A coil electrode having a recessed portion on the opposite surface thereof, a flange member abutting the back surface of the main electrode and a fixing portion at the other end fixed to the recessed portion of the coil electrode, and a portion of the reinforcing member. A vacuum valve, comprising: a reinforcing plate fixed to an outer peripheral portion of a fixing portion of a reinforcing member, disposed in a concave portion of the coil electrode, and having a reinforcing plate whose one surface abuts a rear surface of a flange portion of the reinforcing member, The surface layer of at least one of the reinforcing member and / or the reinforcing plate is composed of a boride coating of at least one element of the constituent components of the reinforcing member or / and the reinforcing plate, in the entire surface or a part of the surface excluding the fixed portion. What is done is the gist. With this configuration, even if a boride coating having a high resistance is used as the surface layer coating instead of the oxide coating, the same action and effect as those of the invention according to claim 1 can be obtained.

The invention according to claim 14 is the above claim 13.
In the vacuum valve described, the boride coating is 0.1
The gist is to have a thickness of ˜50 μm. With this configuration, even when a boride coating is used as the surface layer coating, the desired action and effect can be obtained by limiting the thickness of the coating to 0.1 to 50 μm, as described above.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
2 and FIG. 2B is a sectional view taken along the line AA of FIG. In FIGS. 1 and 2, the same or equivalent members and parts as those in FIGS. 3 to 6 are designated by the same reference numerals, and the duplicated description will be omitted. 1 and 2, the fixed electrode 21 includes a main electrode 10, a coil electrode 23, a reinforcing member 16 and a reinforcing plate 17.
It is composed of The movable electrode 22 is also composed of the main electrode 13, the coil electrode 24, the reinforcing member 18, and the reinforcing plate 17. As shown in (a) and (b) of FIG. 2, the coil electrode 23 has arcuate portions 23a, 23b, 23c, 2 concentric with the fixed energizing shaft 6 (movable energizing shaft 8) and having a current path in the circumferential direction.
3d (24a, 24b, 24c, 24d) is provided,
Further, on the surface facing the main electrode 10 (13), a recess 23e (24e) having a diameter larger than the outer diameter of the reinforcing plate 17 by an appropriate amount (a portion indicated by a dashed line in FIG. 2B) is provided. ing. The recess 23e (24e) is formed by the main electrode 10.
(13) Connection parts 10a, 10b, 10c, 10d
It is formed excluding (13a, 13b, 13c, 13d). Then, the reinforcing plate 1 is placed in the recess 23e (24e).
7 is inserted.

When an external force in the compression direction acts between both electrodes 21, 22, the main electrode 10 (13) is reinforced by the reinforcing member 16 (1
Since it is in contact with 8), it does not deform in the compression direction. When an external force in the pulling direction acts between the electrodes 21 and 22, the coil electrode 23 (24) contacts the reinforcing plate 17,
Further, since the reinforcing plate 17 contacts the reinforcing member 16 (18), it does not deform in the pulling direction. The arc portions 23a to 23d (24a to 2) of the coil electrodes 23 (24) are
The magnetic field in the axial direction is generated between the electrodes 21 and 22 by the current effectively flowing in 4d), and the vacuum arc generated between the electrodes 21 and 22 can be stably blocked with a large current. Further, the reinforcing plate 17 is a recess 23e provided in the coil electrode 23 (24).
(24e), each dimension of the main electrode 10 (13) and the coil electrode 23 (24) and the main electrode 10 (13)
It is not necessary to increase the distance between the coil electrode 23 and the coil electrode 23 (24), and the vacuum valve can be downsized.

However, in order to effectively bring out the above-mentioned advantages, not only the reinforcing member and the reinforcing plate are inserted and arranged, but also only the necessary portion is provided on the surface of the base material of the reinforcing member and the reinforcing plate. It is essential to have a high resistance coating that enables silver brazing and that does not directly electrically short-circuit the main electrode and the coil electrode. Next, Table 1 and Table 2 will be used to describe the evaluation results of each specific example in the case of providing a coating together with comparative examples.

[0027]

[Table 1]

[0028]

[Table 2]

Examples 1 to 5 and Comparative Examples 1 to 3 (Manufacture of test vacuum valve) In the structure of the electrode portion shown in FIG. 5 as a reference example, the fixed electrode 4 has a reinforcing member 16
SUS304 compatible 18% Cr8% Ni balance Fe
A reinforcing member 16 using the alloy as it was was prepared (Comparative Example 1) (surface analysis revealed that Cr-Ni-Fe {JCPDS card No. 33 was found to be a substance originating from the base metal.
-397}). Further, a reinforcing member 16 (Comparative Example 2 to Comparative Example 3 and Examples 1 to 5) in which various states of an oxide film were provided on the surface of this alloy was prepared (surface analysis showed that Cr ₂ O ₃ {JCPDS card. No.38-147
9} etc.). 50% Cu for these reinforcing members 16
The coil electrode 11 made of Cu is attached to the coil electrode 11 made of Cu by a fixing portion 16a which is arranged between the main electrode 10 made of a Cr alloy and the coil electrode 11 made of Cu, and a predetermined amount of a plate-shaped 72% AgCu silver brazing plate is arranged. Fixed, 18% Cr 8% Ni remaining F
The flange portion 16b of the reinforcing member 16 made of the e alloy was brought into contact with the main electrode 10 made of the 50% CuCr alloy.

The movable electrode 5 also has a reinforcing member 18 made of 18% Cr8% Ni balance Fe alloy as the reinforcing member 18.
Was prepared (Comparative Example 1). Separately, a reinforcing member 18 (Comparative Examples 2 to 3 and Examples 1 to 5) in which various states of oxide films were provided on the surface of this alloy was prepared. Similarly, the reinforcing member 18 is composed of the main electrode 13 made of 50% CuCr alloy and C
a fixed portion 18a which is arranged between the coil electrode 14 made of u and a predetermined amount of plate-shaped 72% AgCu silver brazing plate.
To the coil electrode 14 made of Cu,
The flange portion 18b of the reinforcing member 18 made of% Cr8% Ni balance Fe alloy was brought into contact with the main electrode 10 made of the 50% CuCr alloy.

Next, between the flange portion 16b (18b) of the reinforcing member 16 (18) and the coil electrode 11 (14), the reinforcing plate 1 made of 18% Cr8% Ni balance Fe alloy
Inserted 7. The reinforcing plate 17 has the shape described with reference to FIG.

The fixed electrode 4 and the movable electrode 5 having such a structure are arranged in the vacuum chamber 1 so as to face each other. Vacuum container 1
Was constructed by sealing the openings at both ends of the alumina ceramic insulating container 2 with end plates 3a, 3b made of stainless steel. The fixed electrode 4 was attached to the end of a copper fixed current-carrying shaft 6 that penetrated the end plate 3a. The movable electrode 5 was attached to an end portion of a copper movable energizing shaft 8 which penetrated the end plate 3b through a bellows 7 made of stainless steel. The shield 9 is made of stainless steel.

After the reinforcing member 16 (18) or / and the reinforcing plate 17 having a predetermined shape is made of the 18% Cr8% Ni balance Fe alloy, the surface of the reinforcing member 16 (18) or / and the reinforcing plate 17 is formed. The thickness of the oxide film having various coating thicknesses, for example, chromium oxide or a film containing chromium oxide as a main component while adjusting the temperature (eg, 800 to 1000 ° C.) and time (eg, 1 to 1000 minutes) in the presence of oxygen. 0.0
1 μm (Comparative Example 2), 0.1 μm (Example 1), 1 to 5
An oxide film of μm (Example 2, Example 4, Example 5), 50 μm (Example 3), 125 μm (Comparative Example 3) was obtained.
In particular, the quality of various coatings was obtained by adjusting the humidity of the oxygen atmosphere, pretreatment of the surface of the reinforcing member 16 (18) and / or the reinforcing plate 17, or by performing discharge treatment.

[0034] Here, the film mainly composed of chromium oxide or chromium oxide obtained by the above treatment is most preferred coating of only Cr ₂ O ₃ in particular, by the processing conditions, Cr ₂ O _3, Cr _1.3 Fe _0.7 O ₃ , (Fe
_0.6 Cr _0.4 ) ₂ O ₃ , α-Fe ₂ O ₃ , FeCr ₂ O
A mixed film of ₄ , Fe ₃ O ₄ (tetragonal) and Fe ₃ O ₄ (cubic) is obtained.

After arranging the respective component materials thus obtained in the above-mentioned manner, airtight sealing was carried out at 820 to 840 ° C. while silver brazing was performed at the necessary joining portions. In the vacuum valve assembly, the end portion 16c (18) of the reinforcing member 16 (18) is
Ni only in places where it is necessary to improve the brazability of silver such as c).
A plated reinforcing member 16 (18) is prepared and a predetermined amount of 72% AgCu brazing material is used.
8c) and the end of the fixed energizing shaft 6 (end of the movable energizing shaft 8) were fixed by silver brazing (silver brazing part 1). Simultaneously with this step, the reinforcing member 16 (18) and the coil electrode 1
1 (14) is fixed to the fixing portion 16a (18a) by silver brazing (silver brazing portion 2), and the reinforcing member 1
The reinforcing plate 17 was fixed to the outer peripheral portion of the fixing portion 16a (18a) of 6 (18) by silver brazing.

(Evaluation conditions) (1) Breaking characteristics: Diameter 70 mm manufactured under the above-mentioned conditions
The experimental vacuum valve for disconnection test equipped with the electrode of No.1 was attached to the switchgear, and after baking, voltage aging, etc., it was connected to the circuit of 24kV, 50Hz for 1k.
While the current was increased in increments of A, the breaking limits of three vacuum valves were compared and evaluated. In addition, only the result of Example 1 is an average value of three vacuum valves, and other numerical values show the comparison value when the value of Example 1 is 100, with a variation range.
After the breaking test, the experimental vacuum valve was broken and the extent of arc spread was also observed to help judge the breaking performance.

(2) Re-ignition characteristics: diameter 30 mm, thickness 5
The disc-shaped electrode piece of mm is attached to the demountable vacuum valve, and the frequency of re-ignition when the circuit of 24 kV x 500 A is cut 2000 times is determined by the two breakers (6 vacuum valves). It is displayed in consideration of the variation value.

(3) Evaluation of the presence of silver braze after silver brazing; in the vacuum valve assembly process (silver brazing process),
The state of adhesion of the silver brazing material to the reinforcing member / reinforcing plate was evaluated with six vacuum valves. (When the silver brazing material adheres to the reinforcing member / reinforcing plate, part of the main current flows through the adhering part to the reinforcing member /
It diverts to the reinforcing plate and reduces the magnetic field. Furthermore, if the adhered silver brazing material separates from the adhered part, another problem is that it triggers the re-ignition phenomenon). In the evaluation, the state where the silver brazing filler metal is ideally present only in the necessary portion of the reinforcing member / reinforcing plate [A], and the silver brazing filler metal adheres to a few places where the silver brazing filler metal should not be joined. The state where the silver brazing filler metal is adhered in a large number of points [C], the part of the adhered silver brazing filler metal is separated from the adhered portion, separated and scattered into the vacuum valve and dropped. The state was classified into [D] and evaluated (Table 2).

(Evaluation Results) As shown in Table 2, when 18% Cr8% Ni balance Fe alloy is used as the reinforcing member / reinforcing plate, 3 out of 6 are B evaluation and 2 are C evaluation. ,
When one of the six films has a D evaluation (Comparative Example 1) and the thickness of the coating film on the surface is 0.01 μm, one of the six films has an A evaluation,
Five pieces were evaluated as B (Comparative Example 2), and the joining condition was not favorable in all cases. Correspondingly to this, the interruption characteristic and the re-ignition generation characteristic are remarkably lowered as compared with the second embodiment. On the other hand, the thickness of the surface coating of the reinforcing member / reinforcing plate is 0.1 μm
In the case of .about.50 .mu.m (Examples 1 to 3), the interruption characteristic and the re-ignition generation characteristic were in the preferable value ranges as compared with Example 2. However, when the thickness of the surface coating of the reinforcing member / reinforcing plate is 125 μm, 3 out of 6 are C-rated and 3 are D
It was evaluated (Comparative Example 3), and the silver brazing condition was not favorable, and the cutoff characteristics and the re-ignition generation characteristics were remarkably lowered as compared with Example 2. The range of variation was also expanding. As a result, the thickness of the oxide film on the surface of the reinforcing member / reinforcing plate was 0.1.
It was found that the range [μm] to 50 μm is a preferable [A] evaluation. From the X-ray diffraction result of the surface layer, it was confirmed that the oxide film on the surface of the reinforcing member / reinforcing plate was Cr oxide or a mixture of Cr oxide and iron oxide. Even in this case, the same effect is obtained (Examples 4 to 5).

Examples 6 to 7 and Comparative Examples 4 to 5 In the above Examples 1 to 6 and Comparative Examples 1 to 3, the case where 18% Cr8% Ni balance Fe alloy was used as the reinforcing member / reinforcing plate was shown. The technology of the present invention is not limited to this, and for example, 18Cr-12Ni-2.5Mo-0.
Even when 06C (corresponding to SUS316) is used as the reinforcing member / reinforcing plate, the desired effect is exhibited by forming the coating film in the predetermined state (Examples 6 to 7). However, when 18Cr-12Ni-2.5Mo-0.06C is used as it is as a reinforcing member / reinforcing plate, the joining condition is not favorable, and correspondingly, the breaking characteristic and the restriking generation characteristic are compared with those of the second embodiment. And significantly decreased (Comparative Examples 4 to 5).

Example 8 and Comparative Example 6 In the above Examples 1 to 7 and Comparative Examples 1 to 5, the surface layer of the reinforcing member / reinforcing plate was made of Cr oxide or a mixture of Cr oxide and Fe oxide. However, the present invention is not limited to this, and the surface thereof is not limited to Cr oxide and Al.
The effect is obtained even with a coating film of a mixture of oxides (Example 8). However, when the reinforcing member / reinforcing plate was used as it was, the joining condition was unfavorable, and correspondingly, the breaking characteristics and the restriking generation characteristics were remarkably lowered as compared with Example 2 (Comparative Example 6).

Examples 9 to 12 and Comparative Examples 7 to 10 Even when the surface layer of the reinforcing member / reinforcing plate is a mixture of Cr oxide and Si oxide (Examples 9 to 11), Cr oxide and TiO _{2 are used.} Even as a mixture of oxides (Example 12), desired effects are exhibited (Examples 9 to 12). However, when the reinforcing member / reinforcing plate was used as it was, the joining condition was unfavorable, and correspondingly, the breaking characteristics and the re-ignition occurrence characteristics were remarkably lowered as compared with Example 2 (Comparative Examples 7 to 1).
0). In this example, the amount of Cr in the base material was 13 to
Although the case of 15% or more (Examples 8, 9, 12) is shown,
This is because the Cr oxide was obtained more easily when 13 to 15% or more of the base material was used to obtain the Cr oxide mainly composed of Cr ₂ O ₃ . In addition, Cr oxide is replaced with Cr ₂ O
_The reason why the oxide containing ₃ as a main component is used is that it is more stable against heat treatment that is applied when the vacuum valve is assembled and mechanical and electrical shock that is applied when the vacuum valve is turned on and off.

Modifications In the above embodiments, the coil electrode in which the magnetic field acting on the main electrode generates a magnetic field in the vertical direction with respect to the main electrode surface has been described, but if the gist of the present invention is the same, the direction of the magnetic field is changed. The same effect can be obtained regardless of the gradient magnetic field or the horizontal magnetic field.

Further, in the above-mentioned embodiment, an example in which the selective oxidation method is mainly adopted as the method of forming the surface coating layer is shown, but the method of forming the surface coating layer is not limited to this, and ion plating, electron impact Method, a physical vapor deposition method (PVD) such as a sputtering method, a chemical vapor deposition method (CVD), an anodic oxidation method in an electrolytic solution, or a thermal spraying method can exert the same effect with respect to the gist of the present invention.

Further, in the above-mentioned embodiments, the surface coating layer is shown by using an oxide as a typical example. However, a coating film of nitride such as chromium nitride or boride such as chromium boride is used and the thickness thereof is the same as above. Even if it is in the range of 0.1 μm to 50 μm, the same effect is exhibited for the purpose of the present invention.

[0046]

As described above, according to the first aspect of the present invention, a pair of electrodes are arranged in a vacuum container so that they can come in contact with and separate from each other, and each electrode is a main electrode. And a coil electrode, which is disposed on the back surface side of the main electrode, generates a magnetic field on the main electrode surface and has a concave portion on the surface facing the main electrode, and a flange portion contacts the back surface of the main electrode. And a reinforcing member having a fixing portion at the other end fixed to a concave portion of the coil electrode, and a part of the reinforcing member fixed to an outer peripheral portion of the fixing portion of the reinforcing member and disposed in the concave portion of the coil electrode. Is a vacuum valve comprising a reinforcing plate that contacts the back surface of the flange portion of the reinforcing member, wherein at least one surface layer of the reinforcing member and / or the reinforcing plate is the entire surface or one surface excluding the fixed portion. The surface of the part is the structure of the reinforcing member and / or the reinforcing plate. Since it is composed of an oxide film of at least one element of the component, by providing a high resistance oxide film on the entire surface or a part of the surface of the reinforcing member and / or the reinforcing plate excluding the fixed portion, the reinforcing member is not sufficient in terms of space. Fixing between the coil electrodes and between the coil electrodes and between the reinforcing plate and the reinforcing member by silver brazing or the like is performed only in a necessary portion, and the main electrode and the coil electrode do not come into direct electrical contact. Therefore, the current for generating the magnetic field can sufficiently flow through the coil electrode to improve the cutoff characteristic and the re-ignition characteristic. Since the reinforcing plate is provided in the recess of the coil electrode, it is not necessary to increase the distance between the main electrode and the coil electrode, and the size can be reduced.

According to the second aspect of the invention, since the oxide film of at least one element of the constituents of the reinforcing member or / and the reinforcing plate is an oxide film containing chromium oxide as a main component, the vacuum valve is assembled. The stability becomes greater against the mechanical and electrical shocks that are applied when the heat treatment is performed and the vacuum valve is turned on and off. Although the oxide film is preferably made of only chromium oxide qualitatively, even if the oxide film contains chromium oxide as a main component, the above-described desired effect due to the provision of the oxide film can be obtained.

According to the invention of claim 3, the base material of the reinforcing member and / or the reinforcing plate is made of either martensitic stainless steel or martensitic heat resistant steel, and the reinforcing member or / and Since the oxide film of at least one element of the constituent components of the reinforcing plate is an oxide film containing chromium oxide as the main component, it is selected as the base material of martensitic stainless steel or martensitic heat-resistant steel containing chromium as a constituent component. By applying a treatment such as oxidation, an oxide film containing chromium oxide as a main component can be easily formed on the entire surface or a part of the surface of the reinforcing member or / and the reinforcing plate excluding the fixed portion.

According to the invention of claim 4, the base material of the reinforcing member and / or the reinforcing plate is made of either martensitic stainless steel or martensitic heat resistant steel, and the reinforcing member or / and Since the oxide film of at least one element of the constituents of the reinforcing plate is chromium oxide,
By adjusting the humidity of the oxygen atmosphere at the time of selective oxidation and the pretreatment of the surface of the reinforcing member or / and the reinforcing plate, the oxide film of the surface layer can be made into high quality chromium oxide, and the oxide film is provided. The desired effect described above can be further enhanced.

According to a fifth aspect of the present invention, the base material of the reinforcing member or / and the reinforcing plate is made of either ferritic stainless steel or ferritic heat resistant steel, and the reinforcing member or / and reinforcing plate. Since the oxide film of at least one element of the component is an oxide film containing chromium oxide as a main component, even when a ferritic stainless steel or ferritic heat resistant steel containing chromium as a constituent is used as a base material. By subjecting the reinforcing member and / or the reinforcing plate to the fixed portion, an oxide film containing chromium oxide as a main component can be easily formed by performing a treatment such as selective oxidation.

According to the invention of claim 6, the base material of the reinforcing member or / and the reinforcing plate is made of either ferritic stainless steel or ferritic heat-resistant steel, and the reinforcing member or / and reinforcing plate. Since the oxide film of at least one element of the constituent component is chromium oxide, similarly to the above, by adjusting the humidity of the oxygen atmosphere at the time of selective oxidation or the like, the pretreatment of the reinforcing member or / and the reinforcing plate surface, or the like, The oxide film of the surface layer can be made of high-quality chromium oxide, and the above-mentioned desired effect due to the provision of the oxide film can be further enhanced.

According to a seventh aspect of the present invention, the base material of the reinforcing member and / or the reinforcing plate is made of either austenitic stainless steel or austenitic heat resistant steel, and the reinforcing member or / and the reinforcing plate is formed. Since the oxide film of at least one element of the component is an oxide film containing chromium oxide as a main component, even when an austenitic stainless steel or austenitic heat resistant steel containing chromium as a component is used as a base material. By subjecting the reinforcing member and / or the reinforcing plate to the fixed portion, an oxide film containing chromium oxide as a main component can be easily formed by performing a treatment such as selective oxidation.

According to the eighth aspect of the present invention, the base material of the reinforcing member and / or the reinforcing plate is made of either austenitic stainless steel or austenitic heat resistant steel, and the reinforcing member or / and the reinforcing plate is formed. Since the oxide film of at least one element of the component is chromium oxide,
Similarly to the above, by adjusting the humidity of the oxygen atmosphere at the time of selective oxidation, the pretreatment of the reinforcing member or / and the reinforcing plate surface, etc.,
The oxide film of the surface layer can be made of high-quality chromium oxide, and the above-mentioned desired effect due to the provision of the oxide film can be further enhanced.

According to the invention of claim 9, at least one of iron oxide, aluminum oxide, silicon oxide and titanium oxide is present in the oxide film containing chromium oxide as a main component. Even if at least one of iron oxide, aluminum oxide, silicon oxide, and titanium oxide is present in the oxide film, the above-described desired effect due to the provision of the oxide film can be obtained.

According to the tenth aspect of the present invention, the chromium oxide or the oxide film containing chromium oxide as a main component is formed of the oxide film of
Since the thickness is 1 to 50 μm, the thickness of the oxide film is 0.
If the thickness is less than 1 μm, when the silver brazing material is fixed by silver brazing or the like, the silver brazing material or the like may adhere in a granular form to a portion other than a necessary portion, and the barrier properties are deteriorated. In some cases, the re-ignition characteristics, etc. may be deteriorated due to peeling or scattering of the oxides.
By limiting to the range of m, it is possible to surely obtain the above-mentioned desired effect by providing the oxide film.

According to an eleventh aspect of the present invention, there is provided a structure in which a pair of electrodes is disposed in a vacuum container so that the electrodes can come into contact with and separate from each other, and each of the electrodes includes a main electrode and a back surface side of the main electrode. A coil electrode having a concave portion provided on the surface facing the main electrode while generating a magnetic field on the main electrode surface, and a flange portion abutting the back surface of the main electrode and a fixing portion at the other end of the coil electrode. A reinforcing member fixed to the concave portion of the coil electrode, and a part of the reinforcing member fixed to the outer peripheral portion of the fixing portion of the reinforcing member and disposed in the concave portion of the coil electrode, and one surface portion of the flange portion of the reinforcing member. A vacuum valve comprising a reinforcing plate abutting on a back surface, wherein at least one surface layer of the reinforcing member or / and the reinforcing plate has a whole surface or a part of the surface excluding the fixing portion, / And at least one of the components of the reinforcing plate Since it is composed of the nitride film of the element, even if a high resistance nitride film is used as the surface layer film instead of the oxide film, the same effect as the effect of the invention described in claim 1 can be obtained. .

According to the twelfth aspect of the present invention, since the nitride coating has a thickness of 0.1 to 50 μm, even when a nitride coating is used as the surface layer coating, the coating is the same as above. By limiting the thickness of the film to 0.1 to 50 μm, it is possible to surely obtain the above-described desired effect by providing the nitride film.

According to the thirteenth aspect of the present invention, there is provided a structure in which a pair of electrodes are arranged in a vacuum container so as to be freely contactable and separable, and each of the electrodes includes a main electrode and a back surface side of the main electrode. A coil electrode having a concave portion provided on the surface facing the main electrode while generating a magnetic field on the main electrode surface, and a flange portion abutting the back surface of the main electrode and a fixing portion at the other end of the coil electrode. A reinforcing member fixed to the concave portion of the coil electrode, and a part of the reinforcing member fixed to the outer peripheral portion of the fixing portion of the reinforcing member and disposed in the concave portion of the coil electrode, and one surface portion of the flange portion of the reinforcing member. A vacuum valve comprising a reinforcing plate abutting on a back surface, wherein at least one surface layer of the reinforcing member or / and the reinforcing plate has a whole surface or a part of the surface excluding the fixing portion, / And at least one of the components of the reinforcing plate Since it is composed of the boride film of the above element, even if a high resistance boride film is used as the surface layer film instead of the oxide film, the same effect as the effect of the invention according to claim 1 can be obtained. .

According to the fourteenth aspect of the present invention, since the boride coating has a thickness of 0.1 to 50 μm, even when a boride coating is used as the surface layer coating, the coating is the same as above. By limiting the thickness to 0.1 to 50 μm, it is possible to reliably obtain the above-described desired effect by providing the boride coating.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a vacuum valve according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing a configuration of an electrode section in FIG.

FIG. 3 is a vertical sectional view showing a conventional vacuum valve.

FIG. 4 is a cross-sectional view showing a configuration of an electrode portion of Reference Example A.

FIG. 5 is a diagram showing a configuration of an electrode portion of Reference Example C.

6 is an enlarged vertical cross-sectional view of the reinforcing member in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 6 Fixed energizing shaft 8 Movable energizing shaft 10,13 Main electrode 16,18 Reinforcing members 16a, 18a Fixed part 16b, 18b Flange part 21 Fixed electrode 22 Movable electrode 23, 24 Coil electrode 23e, 24e Recessed part

Front Page Continuation (72) Inventor Takashi Kusano 1st in Toshiba Fuchu, Tokyo Fuchu-shi, Toshiba Fuchu factory (72) Inventor Kansei Yo 1 in Toshiba Fuchu-shi, Fuchu, Toshiba (72) Invention Atsushi Yamamoto 1st Toshiba Town, Fuchu City, Tokyo Inside the Fuchu Factory, Toshiba Corporation

Claims (14)

[Claims] 1. A structure in which a pair of electrodes is disposed in a vacuum container so as to be able to come into contact with and separate from each other, wherein each of the electrodes is provided with a main electrode and a back surface side of the main electrode. A coil electrode having a concave portion on the surface facing the main electrode and a flange portion abutting the back surface of the main electrode and the fixing portion at the other end fixed to the concave portion of the coil electrode. And a reinforcing plate part of which is fixed to the outer peripheral portion of the fixing portion of the reinforcing member and is disposed in the recess of the coil electrode, and one surface of which is in contact with the back surface of the flange portion of the reinforcing member. A vacuum valve provided, wherein at least one surface layer of the reinforcing member or / and the reinforcing plate has a whole surface or a part of the surface excluding the fixing portion of a constituent component of the reinforcing member or / and the reinforcing plate. Consist of an oxide film of at least one element A vacuum valve characterized by: 2. The oxide film of at least one element constituting the reinforcing member or / and the reinforcing plate is an oxide film containing chromium oxide as a main component.
Vacuum valve as described. 3. The reinforcing member or / and the reinforcing plate has a base material composed of either martensitic stainless steel or martensitic heat-resistant steel, and at least one of the constituent components of the reinforcing member or / and the reinforcing plate. The oxide films of the two elements are
The vacuum valve according to claim 1, wherein the vacuum valve is an oxide film containing chromium oxide as a main component. 4. A base material of the reinforcing member and / or the reinforcing plate is composed of either martensitic stainless steel or martensitic heat-resistant steel, and at least one of the constituent components of the reinforcing member and / or the reinforcing plate. The oxide films of the two elements are
The vacuum valve according to claim 1, wherein the vacuum valve is chromium oxide. 5. The reinforcing member or / and the reinforcing plate has a base material made of either ferritic stainless steel or ferritic heat resistant steel, and at least one element of the constituent components of the reinforcing member or / and the reinforcing plate. The vacuum valve according to claim 1, wherein the oxide film is an oxide film containing chromium oxide as a main component. 6. The reinforcing member or / and the reinforcing plate has a base material composed of either ferritic stainless steel or ferritic heat-resistant steel, and at least one element of the constituent components of the reinforcing member or / and the reinforcing plate. The vacuum valve according to claim 1, wherein the oxide film is chromium oxide. 7. The reinforcing member or / and the reinforcing plate has a base material composed of either austenitic stainless steel or austenitic heat resistant steel, and at least one element of the constituents of the reinforcing member or / and the reinforcing plate. The oxide film of
The vacuum valve according to claim 1, wherein the vacuum valve is an oxide film containing chromium oxide as a main component. 8. The reinforcing member or / and the reinforcing plate, the base material is composed of either austenitic stainless steel or austenitic heat-resistant steel, at least one element of the constituent components of the reinforcing member or / and the reinforcing plate. The oxide film of
The vacuum valve according to claim 1, wherein the vacuum valve is chromium oxide. 9. The oxide film containing chromium oxide as a main component contains at least one of iron oxide, aluminum oxide, silicon oxide and titanium oxide. Vacuum valve. 10. The vacuum valve according to claim 1, wherein the chromium oxide or the oxide film containing chromium oxide as a main component has a thickness of 0.1 to 50 μm. 11. A structure in which a pair of electrodes is disposed in a vacuum container so as to be able to come into contact with and separate from each other, and each of the electrodes is provided with a main electrode and a rear surface side of the main electrode. A coil electrode having a concave portion on the surface facing the main electrode and a flange portion abutting the back surface of the main electrode and the fixing portion at the other end fixed to the concave portion of the coil electrode. And a reinforcing plate part of which is fixed to the outer peripheral portion of the fixing portion of the reinforcing member and is disposed in the recess of the coil electrode, and one surface of which is in contact with the back surface of the flange portion of the reinforcing member. A vacuum valve provided, wherein at least one surface layer of the reinforcing member or / and the reinforcing plate has a whole surface or a part of the surface excluding the fixing portion of a constituent component of the reinforcing member or / and the reinforcing plate. Consists of a nitride coating of at least one element A vacuum valve characterized by 12. The nitride film has a thickness of 0.1 to 50 μm.
12. The vacuum valve of claim 11, having a thickness of. 13. A vacuum vessel having a structure in which a pair of electrodes is disposed so as to be able to come into contact with and separate from each other, and each of the electrodes is provided with a main electrode and a back surface side of the main electrode. A coil electrode having a concave portion on the surface facing the main electrode and a flange portion abutting the back surface of the main electrode and the fixing portion at the other end fixed to the concave portion of the coil electrode. And a reinforcing plate part of which is fixed to the outer peripheral portion of the fixing portion of the reinforcing member and is disposed in the recess of the coil electrode, and one surface of which is in contact with the back surface of the flange portion of the reinforcing member. A vacuum valve provided, wherein at least one surface layer of the reinforcing member or / and the reinforcing plate has a whole surface or a part of the surface excluding the fixing portion of a constituent component of the reinforcing member or / and the reinforcing plate. Consists of a boride coating of at least one element A vacuum valve characterized by 14. The boride coating has a thickness of 0.1 to 50 μm.
14. The vacuum valve of claim 13, having a thickness of.