Vacuum interrupter and method for manufacturing vacuum interrupter

Abstract

A reinforcing part (6) having a cylindrical peripheral wall (60) with a smaller diameter than that of a cylindrical coil part (3) is provided on the inner peripheral side of the coil part (3) so as to be positioned concentrically. In the coil part (3), a plurality of first slit holes (31) and second slit holes (32) are formed, at predetermined intervals in the circumferential direction, to penetrate the coil part (3) in the radial direction and extend in the axial direction. The reinforcing part (6) has: a surface joining part (61) that is surface-joined to an inner peripheral surface (30a) of the coil part (3); and an annular groove (62) extending in and along the surface joining part (61) in the circumferential direction. The groove (62) is formed to open only on the side facing the inner peripheral surface (30a). The surface joining part (61) is brazed to the inner peripheral surface (30a) via a brazing material (7) provided in the groove (62).

Description

Vacuum interrupter, vacuum interrupter manufacturing method

[0001] The present invention relates to a vacuum interrupter and a method for manufacturing the vacuum interrupter, and relates to a technique that can be applied to, for example, various electric power facilities.

[0002] One example of a vacuum interrupter used in various electric power facilities includes a vacuum vessel having an insulating cylindrical body, in which a pair of electrodes (a fixed electrode and a movable electrode) are disposed so as to be freely connected and separated from each other in the axial direction (hereinafter simply referred to as the axial direction) of the cylindrical body. A pair of current-carrying shafts (leads) are provided in the vacuum vessel to support the back sides (opposite the opposing direction) of each electrode. One of the current-carrying shafts (e.g., the movable current-carrying shaft 12b described below) is supported inside the vacuum vessel via a bellows that is expandable and contractible in the axial direction.

[0003] With a vacuum interrupter configured as described above, one of the current-carrying shafts (the movable current-carrying shaft) can be moved axially while maintaining a vacuum state inside the vacuum vessel (specifically, on the outer periphery of the bellows inside the vacuum vessel), thereby making it possible to connect and disconnect the electrodes and open and close the contacts in accordance with the movement of the current-carrying shaft.

[0004] It is common for each electrode to be configured to have a magnetic field generating function in order to facilitate the desired breaking performance, etc. One example of this configuration is a configuration having a cylindrical coil portion (magnetic field generating coil portion) extending in the axial direction, a contact portion provided on the opposing side (contact side) of the coil portion, and an adapter portion that supports the back side (opposite side of the opposing direction) of the coil portion on a current-carrying shaft.

[0005] When the electrodes of this configuration are brought into contact with and separated from each other to open and close the contacts, stress (such as axial inertial force or mechanical impact force) may be applied to the electrodes. Furthermore, since the coil section is provided with multiple slits to provide a magnetic field generation function, the mechanical strength of the electrodes may be easily reduced, and it may be possible that the desired electrode characteristics (mechanical characteristics, electrical characteristics, etc.) cannot be obtained.

[0006] For this reason, studies have been conducted to provide a cylindrical reinforcing portion concentrically on the inner periphery of the coil portion so that the electrode can withstand the stress and obtain the desired electrode characteristics.

[0007] Patent Documents 1 to 3 disclose embodiments in which the components of an electrode (such as a coil portion, a contact portion, an adapter portion, and a reinforcing portion; hereinafter, simply referred to as electrode elements) are assembled by brazing. In this brazing, for example, when assembling the electrode elements to form a desired electrode shape, a brazing material is placed between (or in the vicinity of) the respective assembly surfaces of two adjacent electrode elements (two electrode elements to be brazed to each other). The assembled assembly is then heated or otherwise melted to melt the brazing material, which then permeates between the respective assembly surfaces (for example, by capillary action), and then solidifies (by lowering the temperature). This allows the respective assembly surfaces to be brazed.

[0008] Although the brazing methods disclosed in Patent Documents 1 to 3 do not disclose the placement of the brazing material, it is possible to consider a method that does not impair the assembly or installation of each electrode element. For example, since the reinforcing portion is assembled (e.g., fitted) so as to be concentrically positioned on the inner periphery of the coil portion, it is desirable to ensure that this assembly is not hindered.

[0009] In this case, for both the coil portion and the reinforcing portion, after assembling the two, they may be brazed to each other (for example, in Patent Document 3, they are brazed to the contact portion indicated by reference numeral 4 and the adapter portion indicated by reference numeral 6) using brazing material that is placed at a location other than between the two (for example, in Patent Document 3, the end faces indicated by reference numerals 1a, 1b, 5a, and 5b).

[0010] JP 2010-267442 A JP 2013-041735 A JP 2018-181681 A

[0011] It is desirable to assemble both the coil portion and the reinforcing portion to each other by brazing, etc. However, if the brazing material is disposed in a location other than between the coil portion and the reinforcing portion as described above, even if it melts, it is difficult for it to penetrate between the two (between the respective assembly surfaces), which may result in insufficient brazing and the risk of not being able to obtain the desired electrode characteristics.

[0012] The present invention has been made in consideration of such technical problems, and aims to provide a technology that can contribute to making it easier to braze both the coil portion and the reinforcing portion and to making it easier to obtain the desired electrode characteristics.

[0013] The vacuum interrupter and the method for manufacturing the vacuum interrupter according to the present invention can contribute to solving the above-mentioned problems.

[0014] First, one embodiment of a vacuum interrupter comprises a vacuum vessel having an insulating cylindrical body, a pair of electrodes arranged within the vacuum vessel facing each other in the axial direction of the cylindrical body so as to be able to move toward and away from each other, and a pair of conductive shafts supporting each of the electrodes on opposite sides of the facing direction.

[0015] Each electrode has a cylindrical coil portion extending in the axial direction, a contact portion provided at an opening in the coil portion in the opposing direction, an adapter portion provided on the opposite side of the coil portion in the opposing direction and supported by the current-carrying shaft, and a reinforcing portion that is cylindrical and has a smaller diameter than the coil portion and is arranged concentrically on the inner side of the coil portion.

[0016] The coil portion has a plurality of slit holes formed at predetermined intervals in the circumferential direction of the coil portion, the slit holes passing through the coil portion in the radial direction and extending in the axial direction.

[0017] The reinforcing portion has a surface-joined portion that is surface-joined on the outer surface of the reinforcing portion to the inner surface of the coil portion, and an annular groove portion that extends in the circumferential direction in the surface-joined portion.

[0018] The groove is open only on the side facing the inner circumferential surface of the coil.

[0019] The surface joint portion is brazed to the inner peripheral surface of the coil portion via a brazing material provided in the groove portion.

[0020] The surface-jointed portion may be annular in shape and have a diameter that expands radially outward from the outer circumferential surface of the reinforcing portion.

[0021] The brazing material may be a filament extending along the groove, and one or more filaments may be provided for each groove.

[0022] Furthermore, when the number of stages of the filament provided in the groove in the axial direction is N, the number of stages of the filament provided in the groove in the radial direction is S, the wire diameter of the filament is φ, the dimension of the groove in the axial direction is w1, and the dimension of the groove in the radial direction is w2, the following formulas (1) and (2) may be satisfied: φN<w1<φ(N+1) (1), φS<w2<φ(S+1) (2).

[0023] The filament may also be characterized in that a cutout portion having a shape penetrating in the axial direction is formed in a part of the circumferential direction, and the cutout portion is elastically deformable so as to expand and contract in the circumferential direction.

[0024] One aspect of the manufacturing method for a vacuum interrupter is characterized by having a brazing material placement process for placing the brazing material in the groove portion, a reinforcing portion assembly process for providing and assembling the reinforcing portion on the inner periphery of the coil portion, and a melting process for heating and melting the brazing material.

[0025] As described above, the present invention can contribute to making it easier to braze both the coil portion and the reinforcing portion, and to making it easier to obtain desired electrode characteristics.

[0026] 1 is a schematic diagram (longitudinal cross section in the axial direction) illustrating the general configuration of a vacuum interrupter 1A according to an embodiment; 2 is a schematic diagram (external view) illustrating the general configuration of an electrode 2 (fixed electrode 2a, movable electrode 2b); 3 is a schematic diagram (longitudinal cross section in the axial direction) illustrating the general configuration of an electrode 2 (fixed electrode 2a, movable electrode 2b); 4 is a schematic diagram (external view) illustrating the general configuration of a coil portion 3; 5 is a schematic diagram (external view) illustrating the general configuration of a contact portion 4; 6 is a schematic diagram (A) illustrating the general configuration of a reinforcing portion 6 ((A) is the case where there is one piece of brazing material 7, and (B) is the case where there are two pieces of brazing material 7); 7 is a schematic diagram showing observation results in a verification example ((A) is the case where there is electrode 2, and (B) is the case where there is electrode 9); 8 is a schematic diagram (longitudinal cross section) illustrating a conventional configuration; 9 is a schematic diagram (external view) illustrating a reinforcing portion 91 of a conventional configuration.

[0027] The vacuum interrupter and the manufacturing method of the vacuum interrupter according to the embodiment of the present invention are completely different from a configuration in which both the coil portion and the reinforcing portion are simply brazed via a brazing material placed at a location other than between the two (hereinafter referred to as simply the conventional configuration).

[0028] That is, this embodiment has a configuration including a surface-bonding portion that is surface-bonded on the outer surface of the reinforcement portion to the inner surface of the coil portion, and an annular groove portion that extends in the circumferential direction of the coil portion (hereinafter simply referred to as the circumferential direction) in the surface-bonding portion and in which brazing material can be provided. The groove portion is open only on the side facing the inner surface of the coil portion. The surface-bonding portion of the reinforcement portion is brazed to the inner surface of the coil portion via the brazing material provided in the groove as described above.

[0029] According to the configuration of this embodiment, the coil portion and the reinforcing portion can be brazed together and assembled so that the assembly of the reinforcing portion to the inner periphery side of the coil portion is not hindered.

[0030] 8 and 9 described later, in the case where a notched groove 93 for placing the brazing material 7 is provided on the outer peripheral edge of the open end face 92 of the reinforcing portion 91 on the adapter portion 5 side, it is possible that the brazing material 7 placed in the notched groove 93 can melt and penetrate between the assembly surfaces (between the inner peripheral surface 30 a and the outer peripheral surface 60 a) of the coil portion 3 and the reinforcing portion 91. However, because the notched groove 93 has a shape that opens on the adapter portion 5 side, it is conceivable that most of the molten brazing material 7 will flow toward the adapter portion 5 (for example, flow along the assembly surface of the adapter portion 5), which may prevent the coil portion 3 and the reinforcing portion 91 from being brazed together.

[0031] On the other hand, in the configuration of this embodiment, the groove provided in the surface joint of the reinforcing part is shaped so that it is open only on the side facing the inner surface of the coil part, so that the melted solder material in the groove can be prevented from flowing toward the adapter part (for example, flowing along the assembly surface of the adapter part).

[0032] This allows the brazing material melted in the groove to easily penetrate between the assembly surfaces of the coil portion and the reinforcing portion (for example, by capillary action), making it easier to braze the coil portion and the reinforcing portion together, which can also contribute to the electrode characteristics.

[0033] As described above, this embodiment has a configuration in which a groove is provided in the surface-joint portion of the outer surface of the reinforcing part that is surface-joined to the inner surface of the coil part, the groove being open only on the side facing the inner surface, and the reinforcing part and the coil part are brazed via the brazing material provided in the groove. Therefore, it is possible to appropriately apply common technical knowledge in various fields (vacuum interrupter field, electrode field, brazing field, etc.) and to appropriately refer to prior art documents, etc. as necessary, and to modify the design, and the following example is one example of such a configuration.

[0034] In the following examples, detailed descriptions will be omitted as appropriate, for example, by referring to the same reference numerals for similar contents. Also, in Fig. 7 described later, the fillet 70 formed by the brazing material 7 is depicted in an exaggerated manner for convenience.

[0035] <Example> <Main Configuration of Vacuum Interrupter> An example of the schematic configuration of a vacuum interrupter 1A according to an embodiment will be described with reference to Fig. 1. This vacuum interrupter 1A includes a vacuum vessel 1 having an insulating cylindrical body 10 sealed at one axial end (fixed side) by a fixed flange 1a and at the other axial end (movable side) by a movable flange 1b.

[0036] In the case of the cylindrical main body 10 shown in Figure 1, a cylindrical shield (arc shield) 11 surrounding the outer periphery of the fixed electrode 2a and the movable electrode 2b described below is supported on the inner periphery of the cylindrical main body 10.

[0037] A columnar fixed-side current-carrying shaft 12a is provided at the center of the fixed-side flange 1a so as to extend from the center to the other axial side (extending from one axial side to the other axial side in FIG. 1 ). The fixed electrode 2a is supported at the end of the fixed-side current-carrying shaft 12a on the other axial side.

[0038] A flange through-hole 13 is provided in the center of the movable side flange 1b, and extends axially through the center. A columnar movable side current-carrying shaft 12b is inserted into the flange through-hole 13 and extends axially.

[0039] The movable electrode 2b is supported at one axial end of the movable current-carrying shaft 12b. The one axial end of the movable current-carrying shaft 12b (the movable electrode 2b side) is supported inside the vacuum vessel 1 of the movable flange 1b via a cylindrical bellows 14 that is axially expandable and contractible and is arranged coaxially with the movable current-carrying shaft 12b.

[0040] The fixed electrode 2a and the movable electrode 2b are provided with slits and the like (specific examples include a first slit 31, a second slit 32, a slit groove 36, and a contact-side slit 41, which will be described later) to provide a magnetic field generating function.

[0041] According to the vacuum interrupter 1A configured as described above, the movable-side current-carrying shaft 12b (and the movable electrode 2b) can be moved in the axial direction while maintaining the vacuum state inside the vacuum vessel 1 (specifically, the outer periphery of the bellows 14 inside the vacuum vessel 1), and the movable electrode 2b can be moved toward or away from the fixed electrode 2a in accordance with the movement of the movable-side current-carrying shaft 12b.

[0042] The materials, shapes, etc. of each component of the vacuum interrupter 1A, as well as the processing methods, assembly methods, and mounting methods of each component, can be appropriately applied in various forms depending on the intended use of the vacuum interrupter 1A, etc.

[0043] For example, among the components of the vacuum interrupter 1A, an insulating material (e.g., alumina ceramics) may be used for the cylindrical body 10, and a metal material (e.g., stainless steel (SUS304), oxygen-free copper, titanium) may be used for the other components. However, it is preferable to select the appropriate material taking into account the possibility of expansion (thermal expansion) and residual stress occurring when assembling the components.

[0044] <Main configuration examples of the fixed electrode 2 a and the movable electrode 2 b> The fixed electrode 2 a and the movable electrode 2 b are configured to have a magnetic field generation function for the purpose of making it easier to exhibit the desired blocking performance, and any configuration may be used as long as the coil portion 3 and the reinforcing portion 6, which will be described later, among the electrode elements of the electrode 2 are brazed together, and examples thereof include those shown in Figures 1 to 6.

[0045] The fixed electrode 2a and the movable electrode 2b may have the same configuration, and hereinafter, as needed, they will be collectively referred to simply as the electrode 2. Furthermore, the fixed-side current-carrying shaft 12a and the movable-side current-carrying shaft 12b will hereinafter, as needed, be collectively referred to simply as the current-carrying shaft 12.

[0046] 1 to 6 includes a coil section (magnetic field generating coil section) 3 having a cylindrical peripheral wall 30 extending in the axial direction, a disk-shaped contact section 4 provided on an open end face 33 on the opposing side (contact side) of the coil section 3, and a disk-shaped adapter section 5 that supports an open end face 34 on the back side (opposite the opposing direction) of the coil section 3 on a current-carrying shaft 12. In addition, a reinforcing section 6 having a cylindrical peripheral wall 60 with a smaller diameter than the coil section 3 is fitted concentrically around the inner periphery of the coil section 3.

[0047] The material, shape, etc. of each electrode element of the electrode 2, as well as the processing method, assembly method, and installation method of each electrode element, can be appropriately adapted in various ways depending on the intended use of the vacuum interrupter 1A. For example, the coil portion 3, the contact portion 4, and the adapter portion 5 are preferably made of a metal material with high conductivity, such as oxygen-free copper. On the other hand, the reinforcing portion 6 is preferably made of a metal material with high mechanical strength, such as stainless steel (SUS304).

[0048] <Configuration example of coil section 3> The coil section 3 has a first slit hole 31 that penetrates the peripheral wall 30 in the radial direction (hereinafter simply referred to as the radial direction) of the coil section 3 and extends in the axial direction (in the figure, a shape that extends along the axis 35, in the so-called Z-winding direction) and opens to the opening end face 33 side, and a plurality of second slit holes 32 that penetrate like the first slit hole 31 and extend in the axial direction and open to the opening end face 34 side, which are formed alternately at a predetermined interval in the circumferential direction of the coil section 3 (six of each in the figure).

[0049] A slit groove 36 is formed at the opening end surface 33 on the opening side of each first slit hole 31, and extends radially therethrough.

[0050] The first slit hole 31, the second slit hole 32, and the slit groove 36 may be formed in various ways as long as they are capable of generating a desired magnetic field. In the case of the first slit hole 31 and the second slit hole 32 shown in the drawing, they extend from the vicinity of the center of the coil portion 3 in the axial direction to the respective opening sides (opening end faces 33, 34 sides) and are inclined at an angle (inclination angle) α with respect to the axis 35 of the coil portion 3, but are not limited to this.

[0051] The angle α can be set appropriately, for example, within a range of 60° to 80°. The circumferential opening angles of the first slit holes 31, the second slit holes 32, and the slit grooves 36 relative to the axis 35 of the coil portion 3 can also be set appropriately (for example, set to a constant value), for example, within a range of [540 / s]° to [1440 / s]° (where s is the total number of the first slit holes 31, the second slit holes 32, and the slit grooves 36).

[0052] In the case of the coil portion 3 shown in the figure, a surface-bonded portion 30b having a shape that narrows radially inward is formed on the inner circumferential surface 30a on the adapter portion 5 side (in the figure, the portion facing the surface-bonded portion 61, which will be described later). This makes it easier for the surface-bonded portion 30b of the inner circumferential surface 30a of the coil portion 3 to be surface-bonded to the outer circumferential surface 60a of the reinforcing portion 6.

[0053] <Configuration example of contact portion 4> The contact portion 4 can be configured to obtain a desired magnetic field generation function, similar to the coil portion 3. As a specific example, there can be mentioned a mode in which a plurality of contact-side slit holes 41 are formed at predetermined intervals in the circumferential direction of the contact portion 4, each of which has a shape that penetrates the contact portion 4 in the thickness direction (axial direction) and extends in the radial direction and has a shape that opens to the outside in the radial direction (toward the outer peripheral end face 40).

[0054] In the case of each contact-side slit 41 shown in the figure, the radially inner end 42 of the contact-side slit 41 is positioned away from the axis 35, and as it approaches the radially outer side, it is inclined so as to be biased from the radial direction to one side in the circumferential direction (in the figure, the clockwise direction when viewed from the opposing side). Each contact-side slit 41 of such a shape forms a spiral configuration as a whole, as shown in Figure 5.

[0055] Furthermore, the contact portion 4 in the figure has the same number of contact-side slit holes 41 as the slit grooves 36, and the contact-side slit holes 41 are provided on the opening end surface 33 of the coil portion 3 so that the outer peripheral end surface 40 side (opening side) of the contact-side slit holes 41 is positioned opposite the slit grooves 36. This results in a configuration in which the first slit holes 31 and the contact-side slit holes 41 communicate with each other via the slit grooves 36.

[0056] <Configuration example of adapter unit 5> The adapter unit 5 may be configured in various ways as long as it can support the open end surface 34 on the back side (opposite the facing direction) of the coil unit 3 on the current-carrying shaft 12. For example, in the case of the adapter unit 5 shown in the figure, the center of the adapter unit 5 is supported by the current-carrying shaft 12.

[0057] Furthermore, in the case of the adapter part 5 in the figure, it is configured separately from the coil part 3, but this is not limiting and it may be configured integrally with the coil part 3. In this case, the coil part 3 and the adapter part 5 form a cylindrical structure with a bottom as a whole.

[0058] <Configuration example of reinforcing portion 6> In the reinforcing portion 6, a surface-joining portion 61 that is surface-joined to the inner surface 30a of the coil portion 3 is formed on the outer peripheral surface 60a of the peripheral wall 60. In addition, an annular groove portion 62 that extends circumferentially in the axial center of the surface-joining portion 61 is formed in the central portion, and the groove portion 62 is configured to allow the provision of a brazing material 7.

[0059] Various configurations of the surface-bonding portion 61 are possible as long as it can be surface-bonded to the inner peripheral surface 30a with the reinforcing portion 6 provided on the inner peripheral side of the coil portion 3. In the case of the reinforcing portion 6 shown in the figure, an annular surface-bonding portion 61 that expands radially outward is formed at a location on the outer peripheral surface 60a of the peripheral wall 60 on the adapter portion 5 side that faces the surface-bonded portion 30b, and the surface-bonding portion 61 is configured to be easily surface-bonded to the surface-bonded portion 30b, but is not limited to this.

[0060] For example, the surface-bonded portion 30b and the surface-bonded portion 61 in the figure are formed so as to face each other only in a partial axial region (the region on the adapter portion 5 side in the figure) on the inner surface 30a and the outer surface 60a, respectively, but they may also be formed over the entire axial region, or may be formed only in the central region in the axial direction or the region on the contact portion 4 side.

[0061] The groove portion 62 is open only on the side facing the inner surface 30a of the coil portion 3, and the radially inner side and axial side of the groove portion 62 are shielded by the groove inner wall surface 63.

[0062] As described above, the groove 62 is open only on the side facing the inner peripheral surface 30a of the coil portion 3, and various configurations are possible as long as the desired brazing material 7 can be placed therein. In the case of the groove 62 shown in the drawing, the cross-sectional shape (axial direction) of the groove inner wall surface 63 is U-shaped, but it may also be other shapes such as a U-shape or a V-shape.

[0063] <Configuration example of solder material 7> The solder material 7 can be provided so as to extend circumferentially relative to the groove portion 62 so as not to interfere with the assembly of the reinforcing portion 6 to the inner periphery of the coil portion 3. When the solder material 7 provided in the groove portion 62 is melted and then solidified, it is sufficient that the coil portion 3 and the reinforcing portion 6 can be soldered together, and various configurations can be applied.

[0064] For example, if the coil portion 3 is made of oxygen-free copper and the reinforcing portion 6 is made of stainless steel, the brazing filler metal 7 may have a melting point lower than that of the oxygen-free copper. For example, an Ag-based material (such as an Ag-Cu-based material) may be used.

[0065] Furthermore, for example, when a long linear brazing material product that can be plastically deformed by bending or the like is used as the brazing material 7, the brazing material product may be formed into a molded body (hereinafter simply referred to as a filament) having a shape extending along the groove 62. Specific examples include applying a filament obtained by winding the brazing material product along the groove 62 (for example, by winding it around the groove 62 by one turn or less), or fitting a filament obtained by previously molding the brazing material product into the groove 62.

[0066] The brazing material 7 made of the filament as described above may be provided in a single piece (one row in the axial direction) as shown in FIG. 6(A), or in a plurality of pieces (two rows in the axial direction in FIG. 6(B)).

[0067] Alternatively, the brazing material product may be wound spirally around the groove 62 (a predetermined number of turns), thereby forming the spiral filament. When forming such a spiral filament, the number of stages in the axial direction of the filament increases by one each time one turn is wound around the groove 62 and the next turn begins.

[0068] Alternatively, the brazing material product may be wound spirally around the groove 62 (a predetermined number of turns), thereby forming the spiral filament. When forming such a spiral filament, the number of radial stages of the filament increases by one each time one turn is wound around the groove 62 and the next turn begins.

[0069] When using the brazing filler material 7 made of the filaments as described above, it is possible to appropriately design it so as to satisfy the following formulas (1) and (2). Here, the number of axial rows of filaments provided in the grooves 62 is N, the number of radial rows of filaments provided in the grooves 62 is S, the wire diameter of the filaments is φ, the groove width dimension (axial dimension) of the grooves 62 is w1, and the depth dimension (radial dimension) of the grooves 62 is w2. φN<w1<φ(N+1) ... (1) φS<w2<φ(S+1) ... (2)

[0070] By appropriately designing the groove 62 so as to satisfy these formulas (1) and (2), the entire brazing material 7 of the filament can be easily accommodated within the groove 62, and assembly of the reinforcing portion 6 to the inner periphery of the coil portion 3 can be prevented from being hindered. In addition, a suitable excess space 64 can be provided between the brazing material 7 provided in the groove 62 and the groove inner wall surface 63. In this case, it may be easier to arrange the brazing material 7 in the groove 62.

[0071] The brazing material 7 may have a structure with appropriate elasticity (elasticity that does not cause plastic deformation), which allows it to be snap-fit ​​into the groove 62. Specifically, in the case of the brazing material 7 shown in the figure, a notch 71 that penetrates the brazing material 7 in the axial direction is formed in a part of the circumferential direction.

[0072] In the case of such brazing material 7, the cutout portions 71 are elastically deformed so as to expand in the circumferential direction to increase their diameter, and then the brazing material 7 is arranged concentrically with the outer periphery of the groove portion 62, and then the brazing material 7 is elastically restored, so that the brazing material 7 can be fitted into the groove portion 62. In addition, the brazing material 7 can be prevented from coming off the groove portion 62, for example.

[0073] When a plurality of brazing filler metals 7 having cutout portions 71 are provided, it is preferable to appropriately set the cutout portions 71 of the brazing filler metals 7 so that they do not overlap in the axial direction. For example, in the case of the cutout portions 71 of the two brazing filler metals 7 shown in Fig. 6(B), the cutout portions 71 can be set to be positioned opposite each other in the radial direction (for example, set to be positioned on the front side and the back side in Fig. 6(B)).

[0074] If the brazing filler material 7 made of a wire cannot be positioned as desired in the groove portion 62, for example, a part of the brazing filler material 7 may protrude outward from the opening of the groove portion 62 (hereinafter simply referred to as a protruding state). Such a protruding state of the brazing filler material 7 can be recognized, for example, when the inner peripheral surface 30 a or the opening end surface 33 of the coil portion 3 collides with the protruding portion of the brazing filler material 7 while an operator is assembling the reinforcing portion 6 on the inner peripheral side of the coil portion 3.

[0075] If a protruding state of the brazing material 7 is recognized, the assembly work may be stopped, and the cause of the protruding state may be eliminated (for example, by correcting distortion of the filament or by replacing it, by changing the number of stages in the axial or radial direction of the filament, or by reviewing the assembly work), and then the assembly work may be performed again.

[0076] Furthermore, if the solder material 7 is elastic as described above or if excess space 64 is formed, even if the inner surface 30a or the opening end face 33 of the coil portion 3 collides with the protruding portion of the solder material 7 during assembly, it may be possible to continue the assembly work by further pressing it in while applying appropriate pressure, and there is a good chance that the entire solder material 7 will be contained within the groove portion 62.

[0077] <Example of a method for assembling each electrode element> Each electrode element of the electrode 2 can be assembled using appropriate brazing material, but assembling the reinforcing portion 6 to the inner circumferential side of the coil portion 3 can be done by sequentially performing a brazing material placement process, an assembly process, and a melting process as shown below.

[0078] First, in the brazing material placement step, brazing material 7 is provided in the groove 62 of the reinforcing portion 6, as shown in Fig. 6, for example. Then, in the assembly step, the reinforcing portion 6 is fitted concentrically to the inner periphery of the coil portion 3, thereby assembling the coil portion 3 and the reinforcing portion 6 as shown in Fig. 3, for example, to obtain an assembly in which the surface-to-surface joining portion 61 and the surface-to-be-joined portion 30b are surface-to-surface joined.

[0079] Next, in the melting step, the brazing material 7 is heated to a molten state, for example, by placing the assembly in a heating furnace. The molten brazing material 7 penetrates widely between the surface-to-surface joining portion 61 and the surface-to-be-joined portion 30b (between the respective assembly surfaces) by, for example, capillary action, and then solidifies by lowering the temperature. This brazing process results in the surface-to-surface joining portion 61 and the surface-to-be-joined portion 30b being brazed together.

[0080] As described above, of the reinforcing portion 6 assembled on the inner periphery of the coil portion 3, the portions facing the first slit hole 31 and the second slit hole 32 of the coil portion 3 can be viewed through the first slit hole 31 and the second slit hole 32, respectively.

[0081] For example, when the radially inner side of the second slit hole 32 is viewed from the outside, it is also possible to observe the surface joint portion 61 and the groove portion 62 of the reinforcing portion 6 as shown in FIG. 8(A) described later.

[0082] <Verification Example> Next, a plurality of electrodes 2 were produced based on the example, and the assembly properties (brazing properties) of both the coil portion 3 and the reinforcing portion 6 were evaluated by the method described below. Note that, as comparative examples, a plurality of electrodes 9 shown in Figs. 8 and 9 were also produced, and similar assembly properties were evaluated for each electrode 2.

[0083] First, the radially inner sides of the six second slit holes 32 formed in the coil portion 3 of each electrode 2 were observed from the outside. As a result, it was observed that fillets 70 made of the brazing material 7 were formed in almost all of the second slit holes 32 of each electrode 2, as shown in Figure 7(A) . Furthermore, when both the coil portion 3 and the reinforcing portion 6 of each electrode 2 were cut along the axis 35 and the space between the surface-to-be-joined portion 61 and the surface-to-be-joined portion 30b was observed through the cut surface, it was confirmed that the brazing material 7 had permeated widely between the two, and that the brazing material had been brazed as desired.

[0084] On the other hand, when each electrode 9 was observed through each second slit 32 in the same manner as in the case of electrode 2, it was found that a small fillet 70 was formed by the brazing material 7 in only a part of each second slit 32 as shown in Fig. 7(B) , but the fillet 70 could not be observed in most of the second slits 32. Furthermore, when both the coil portion 3 and the reinforcing portion 6 of each electrode 9 were cut along the axis 35 and the area between the surface-joined portion 94 and the surface-joined portion 30b was observed through the cut surface, it was confirmed that the brazing was insufficient compared to the case of electrode 2.

[0085] Therefore, according to the embodiment, it was found that the electrode 2 can be produced by brazing both the coil portion 3 and the reinforcing portion 6 as desired, and the desired electrode characteristics can be easily obtained.

[0086] Although the present invention has been described in detail above only with respect to the specific examples, it will be apparent to those skilled in the art that various modifications are possible within the scope of the technical concept of the present invention, and it is natural that such modifications fall within the scope of the claims.

[0087] DESCRIPTION OF SYMBOLS 1A... Vacuum interrupter 2a... Fixed electrode, fixed side current-carrying shaft 12a 2b... Movable electrode, movable side current-carrying shaft 12b 3... Coil portion, 30a... Inner wall surface, 30b... Surface-bonded portion, 31... First slit hole, 32... Second slit hole, 36... Slit groove 4... Contact portion 5... Adapter portion, 6... Reinforcement portion, 61... Surface-bonded portion, 62... Groove portion, 63... Groove inner wall surface, 64... Surplus space 7... Brazing material, 71... Notch portion

Claims

a pair of electrodes disposed within the vacuum vessel facing each other in the axial direction of the cylindrical body so as to be able to come into contact with and separate from each other; and a pair of current-carrying shafts supporting each of the electrodes on opposite sides of the opposing direction, each of the electrodes having: a cylindrical coil portion extending in the axial direction, a contact portion disposed at an opening of the coil portion in the opposing direction, an adapter portion disposed on the opposite side of the coil portion in the opposing direction and supported by the current-carrying shaft, and a reinforcing portion having a cylindrical shape with a smaller diameter than the coil portion and concentrically disposed on the inner periphery of the coil portion, the coil portion having a plurality of slit holes formed at predetermined intervals in the circumferential direction of the coil portion and piercing the coil portion in the radial direction and extending in the axial direction, the reinforcing portion having: a surface-bonding portion which is surface-bonded on the outer periphery of the reinforcing portion to the inner periphery of the coil portion, and an annular groove portion which extends in the circumferential direction at the surface-bonding portion, A vacuum interrupter characterized in that the groove portion is open only on the side facing the inner circumferential surface of the coil portion, and the surface joint portion is brazed to the inner circumferential surface of the coil portion via a brazing material provided in the groove portion.

2. A vacuum interrupter as set forth in claim 1, wherein said surface joint portion is annular in shape and expands radially outward from the outer circumferential surface of said reinforcing portion.

3. A vacuum interrupter as claimed in claim 1, characterized in that the brazing material is a filament extending along the groove, and one or more filaments are provided for each groove.

4. A vacuum interrupter according to claim 3, characterized in that, when the number of stages of the filament provided in the groove in the axial direction is N, the number of stages of the filament provided in the groove in the radial direction is S, the wire diameter of the filament is φ, the dimension of the groove in the axial direction is w1, and the dimension of the groove in the radial direction is w2, the following formulas (1) and (2) are satisfied: φN<w1<φ(N+1) ... (1) φS<w2<φ(S+1) ... (2).

5. A vacuum interrupter as described in claim 3, characterized in that the filament has a cutout portion formed in part of the circumferential direction that penetrates in the axial direction, and the cutout portion is elastically deformable so as to expand and contract in the circumferential direction.

6. A method for manufacturing a vacuum interrupter as claimed in any one of claims 1 to 5, comprising: a brazing material placement step of placing the brazing material in the groove; a reinforcing portion assembly step of providing and assembling the reinforcing portion on the inner periphery of the coil portion; and a melting step of heating and melting the brazing material.

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