Bearing structure of movable side energizing shaft, vacuum interrupter, and vacuum interrupter manufacturing method

Abstract

The present invention is applied with a bearing (4) comprising: a flange-like part (5) that is in the form of a ring having a diameter larger than an opening diameter of a flange through-hole (3) on the other side in the shaft center direction; and a cylindrical wall part (6) that extends from the inner circumferential edge part of the flange-like part (5) along the shaft center direction. On the cylindrical wall part (6), claw parts (61) are formed on the outer circumferential surface (6b), and the outer diameter of the location where the claw parts (61) are formed is larger than the opening diameter of the flange through-hole (3) on one side in the shaft center direction. Further, on the cylindrical wall part (6), a plurality of slit holes having a shape that penetrates in the radial direction and extends in the shaft center direction and a shape that opens to one side in the shaft center direction are formed in the circumferential direction at prescribed intervals. Each piece of the cylindrical wall part, which is a site between the slit holes, is elastically deformable in the radial direction.

Description

Bearing structure for moving-side current-carrying shaft, vacuum interrupter, and manufacturing method of vacuum interrupter

[0001] The present invention relates to a bearing structure for a movable current-carrying shaft, a vacuum interrupter, and a manufacturing method for a vacuum interrupter, and relates to technology that can be applied to, for example, various electric power facilities.

[0002] For example, one example of a vacuum interrupter used in various electric power facilities has a vacuum vessel formed by sealing one side (fixed side) and the other side (movable side) in the axial direction (hereinafter simply referred to as the axial direction) of an insulating cylindrical body with a fixed flange and a movable flange, respectively. Within this vacuum vessel, both a fixed electrode and a movable electrode are arranged so as to face each other in the axial direction.

[0003] A fixed-side current-carrying shaft is provided on the fixed-side flange inside the vacuum vessel so as to extend axially from the inside of the vacuum vessel, and a fixed electrode is supported on the end of the fixed-side current-carrying shaft.

[0004] The movable flange has a flange through-hole that passes through the flange in the axial direction, and a bearing is provided in the flange through-hole to guide the movable current-carrying shaft in the axial direction (for example, to guide it in a non-rotatable state). The movable current-carrying shaft is supported inside the vacuum vessel of the movable flange via a bellows that is expandable and contractible in the axial direction.

[0005] With a vacuum interrupter configured as described above, the movable current-carrying shaft (and the movable electrode) can be moved while being guided in the axial direction while maintaining a vacuum state inside the vacuum container (specifically, on the outer periphery of the bellows inside the vacuum container), and the movable electrode can be moved toward or away from the fixed electrode (the contacts are opened and closed) in accordance with the movement of the movable current-carrying shaft.

[0006] When the movable current-carrying shaft is moved in the axial direction, if frictional force occurs between the movable current-carrying shaft and the bearing, the frictional force may cause the bearing to come out of the flange through-hole and fall off. In such a case, as disclosed in Patent Document 1, for example, an adhesive may be used to adhere the bearing to the movable flange to prevent the bearing from falling off the flange through-hole.

[0007] Furthermore, if the movable current-carrying shaft rotates, the rotational force may be applied to the bellows or the like, which may result in damage, etc. In such a case, the bearing may be configured to guide the movable current-carrying shaft in the axial direction while preventing it from rotating (for example, in Patent Document 2, an abutment surface (reference numeral 12) corresponding to the two-face width is formed in an insertion guide (reference numeral 11)).

[0008] In addition, a configuration is also known in which the diameter of the opening side of the cylindrical wall portion (guide hole) of the bearing through which the movable current shaft is inserted is increased to allow a certain degree of radial oscillation of the movable current shaft (for example, the configuration shown in Patent Document 3).

[0009] Japanese Patent Laid-Open No. 9-17298 Japanese Patent Laid-Open No. 2016-535400 Japanese Patent Laid-Open No. 2016-110920

[0010] To bond the bearing to the movable flange using adhesive, for example, the adhesive is placed between the bearing and the movable flange and then dried and solidified. However, since it takes a certain amount of time for the adhesive to reach this solidified state, there is a risk of reduced productivity, etc.

[0011] Furthermore, since many adhesives are flammable, the heat resistance temperature of the vacuum interrupter may be reduced, which may limit the use of the vacuum interrupter (for example, limiting the temperature at the adhesive-bonded portion).

[0012] It is also possible to fasten the bearing to the movable flange using bolts or the like instead of adhesive, but this may increase the number of assembly steps, make the structure more complex, larger, and more expensive.

[0013] Therefore, it is desirable to prevent the bearing from coming off the flange through-hole without using adhesives, bolts, or the like.

[0014] The present invention has been made in consideration of such technical challenges, and aims to provide a technology that can prevent a bearing from detaching from a flange through-hole without using adhesives, bolts, etc., and that can contribute to improved productivity, etc.

[0015] The bearing structure for a movable current-carrying shaft, the vacuum interrupter, and the method for manufacturing a vacuum interrupter according to the present invention can contribute to solving the above-mentioned problems.

[0016] First, one aspect of the bearing structure for the movable-side current-carrying shaft is a bearing structure for the movable-side current-carrying shaft that supports a fixed electrode and a movable electrode that are arranged opposite each other in the axial direction of an insulating cylindrical body within a vacuum vessel having the cylindrical body, so that the movable electrode can move freely in the axial direction.

[0017] The cylindrical main body is sealed at its fixed side, which is one side in the axial direction, by a fixed side flange, and at its movable side, which is the other side in the axial direction, by a movable side flange, the movable side flange is provided with a flange through hole that passes through the movable side flange in the axial direction, the movable side current shaft is inserted into the flange through hole and extends in the axial direction, the one side of the movable side current shaft is supported inside the vacuum vessel of the movable side flange via a bellows that is expandable and contractible in the axial direction, and a bearing that guides the movable side current shaft in the axial direction in a non-rotatable state is provided in the flange through hole relative to the flange through hole.

[0018] The bearing has a flange-shaped portion that is annular and has a larger diameter than the opening diameter of the opening on the other side of the flange through hole, and that extends along the opening edge surface of the opening on the other side, and a cylindrical wall portion that extends from the inner peripheral edge of the flange-shaped portion to the one side, is inserted through the flange through hole from the other side toward the one side, and guides the movable side current-carrying shaft that is inserted through the inner peripheral surface of the cylindrical portion in the axial direction.

[0019] The cylindrical wall portion has a claw portion formed on its outer surface that protrudes radially outward from the cylindrical wall portion, and a plurality of slit holes that penetrate the cylindrical wall portion in the radial direction, extending in the axial direction and opening to one side, are formed at predetermined intervals around the circumferential direction of the cylindrical wall portion, and each cylindrical wall piece that is a portion of the cylindrical wall portion between each of the slit holes in the circumferential direction is elastically deformable in the radial direction, and the outer diameter of the portion of the cylindrical wall portion where the claw portion is formed is larger than the opening diameter of the opening on one side of the flange through hole.

[0020] The flange-shaped portion and the claw portion are spaced apart by L, and the flange through-hole is axially spaced by T, satisfying the following formula (1): L≧T (1).

[0021] Furthermore, when the dimensional tolerance of the diameter of the flange through-hole is Δφ, the dimension of the claw portion in the protruding direction is t1, the clearance dimension between the cylindrical wall portion and the movable-side current-carrying shaft is C, the dimensional tolerance related to T is ΔT, and the dimension of the gap provided between the opening edge surface of the one opening and the claw portion is α, the following equations (2) and (3) may be satisfied: Δφ<t1<C (2), L=T+ΔT+α (3).

[0022] The claw portion may also be shaped to protrude radially outward as it approaches the other side from the one side, and the surface of the claw portion on the other side may be formed flat along the opening edge surface of the opening on the one side of the flange through hole.

[0023] Furthermore, at least one recess may be formed on the opening edge surface of the opening on the other side, and a protrusion that can be fitted into the recess may be formed on the flange-shaped portion at a position opposite the recess.

[0024] The recesses may also be formed in multiple numbers at predetermined intervals in the circumferential direction on the opening edge surface of the other opening, and may be formed so as to be rotationally symmetric on the opening edge surface when the axial direction is the axis of symmetry.

[0025] The protrusion may be formed on the flange portion on the side of the base of the cylindrical wall piece.

[0026] Furthermore, when the dimensional tolerance for T is ΔT, the dimension of the gap between the opening edge surface of the opening on one side and the claw portion is α, and the dimension of the protrusion in the protruding direction of the protrusion is t2, the following formula (4) may be satisfied: t2>ΔT+α (4).

[0027] One aspect of the vacuum interrupter is characterized by having the above-described bearing structure for the movable-side current-carrying shaft.

[0028] One aspect of a manufacturing method for a vacuum interrupter is characterized by comprising: a vacuum brazing step of inserting a movable-side current-carrying shaft into a flange through-hole and extending it in the axial direction, and brazing one side of the movable-side current-carrying shaft to the inside of the vacuum vessel of the movable-side flange via the bellows; and a bearing engagement step of fitting the bearing into the flange through-hole from the other side of the movable-side current-carrying shaft after the vacuum brazing step.

[0029] As described above, according to the present invention, it is possible to prevent the bearing from coming off the flange through-hole without using adhesives, bolts, etc., which can contribute to improved productivity, etc.

[0030] 1A and 1B are schematic diagrams illustrating the general configuration of a vacuum interrupter 1A according to a first embodiment (longitudinal cross-sectional view in the axial direction); Schematic diagrams illustrating a main portion (the location of the bearing 4) of FIG. 1 (enlarged view); Schematic diagrams illustrating the general configuration of the bearing 4 ((A) is a view viewed from the radial outside, and (B) is an enlarged view of the area surrounded by the symbol X in (A)); Schematic diagrams illustrating the general configuration of the bearing 4 ((A) is a view viewed from one side in the axial direction, (B) is a view viewed from the other side in the axial direction, and (C) is a radial cross-sectional view of the movable-side current-carrying shaft 13b); and Schematic diagrams illustrating the general configuration of the movable-side flange 1b ((A) is a longitudinal cross-sectional view in the axial direction (cross-sectional view taken along line B-B in (B)), and (B) is a view viewed from the other side in the axial direction).

[0031] The bearing structure for the movable-side current-carrying shaft, the vacuum interrupter, and the manufacturing method for the vacuum interrupter according to the embodiments of the present invention are completely different from a configuration in which the bearing is simply adhered to the movable-side flange using an adhesive (hereinafter referred to as simply the conventional configuration).

[0032] That is, this embodiment is configured to use a bearing that can be inserted into the flange through-hole with elastic deformation (that can be engaged with a so-called snap-fit ​​structure).

[0033] Specifically, a bearing is applied that has a flange-shaped portion that is annular and has a larger diameter than the opening diameter of the opening on the other axial side (movable side) of the flange through-hole, and a cylindrical wall portion that extends axially from the inner peripheral edge of the flange-shaped portion.

[0034] The cylindrical wall portion of this bearing has a claw portion formed on its outer surface that protrudes radially outward from the cylindrical wall portion, and the outer diameter of the point where the claw portion is formed is larger than the opening diameter of the opening on one axial side (fixed side) of the flange through hole.

[0035] Furthermore, the cylindrical wall portion has a plurality of slit holes formed at predetermined intervals in the circumferential direction (hereinafter simply referred to as the circumferential direction) of the cylindrical wall portion, the slit holes penetrating the cylindrical wall portion in a radial direction (hereinafter simply referred to as the radial direction) and extending in the axial direction and opening to one side in the axial direction, so that each cylindrical wall piece between the slit holes in the cylindrical wall portion is elastically deformable in the radial direction.

[0036] Furthermore, when the dimension between the flange-shaped portion and the claw portion is L and the dimension in the axial direction of the flange through-hole is T, the following formula (1) is satisfied.

[0037] L≧T ... (1) When the cylindrical wall portion of such a bearing is inserted into the flange through hole from the other axial side toward one axial side, the cylindrical wall piece elastically deforms radially inward while the claw portions of the cylindrical wall portion are positioned within the flange through hole. Then, after the claw portions of the cylindrical wall portion disengage from the flange through hole toward one axial side, the cylindrical wall piece elastically returns to its original position. As a result, the bearing engages with the flange through hole in a position where the movable flange (the hole wall of the flange through hole) is sandwiched axially between both the flange portion and the claw portions.

[0038] In this manner, a bearing engaged with a flange through-hole can be prevented from coming off the flange through-hole (the engaged state can be maintained) without using adhesive, bolts, etc. Furthermore, because adhesive is no longer necessary, restrictions on the use of vacuum interrupters, as in conventional configurations, can be avoided.

[0039] To create a vacuum inside the vacuum vessel, the components that create the vacuum (e.g., the cylindrical body, fixed flange, movable flange, bellows, movable conductive shaft, etc.) can be assembled using a vacuum brazing process.

[0040] However, in the vacuum brazing process, the brazing material placed at the assembly location is heated and melted, so the presence of a flammable adhesive, as in the conventional configuration, may hinder (or make impossible) the vacuum brazing process. Therefore, when using an adhesive, the movable-side current-carrying shaft is inserted into the flange through-hole in advance, extending in the axial direction, and then the vacuum brazing process as described above is performed, and the bearing is then fitted into the movable-side current-carrying shaft from the other axial side and bonded to the movable-side flange.

[0041] On the other hand, the bearing according to this embodiment can be easily constructed using various materials as long as it can be inserted into the flange through-hole with elastic deformation. For example, if the bearing according to this embodiment is made of a resin material, and the heat resistance temperature of the resin material is higher than the vacuum brazing temperature, the bearing may be engaged with the flange through-hole in advance in a step prior to the vacuum brazing step described above.

[0042] After the vacuum brazing process, each component may undergo thermal expansion depending on its material and shape. For example, thermal expansion of the movable flange may result in dimensional tolerances in the axial dimension (T) and diameter of the flange through-hole.

[0043] The bearing of this embodiment may be designed appropriately in advance, taking into consideration the dimensional tolerances and the like due to the vacuum brazing process described above (for example, as in Example 1 described below, it may be designed to satisfy the formulas (2) and (3)). This makes it possible to engage the bearing with the flange through hole as desired in a step subsequent to the vacuum brazing process, even if a dimensional tolerance occurs in the flange through hole due to the vacuum brazing process.

[0044] This embodiment only needs to have a bearing structure that can be inserted into the flange through-hole with elastic deformation as described above, and the design can be modified by appropriately applying common technical knowledge from various fields (vacuum interrupter field, bearing field, mechanical joining field, vacuum brazing field, etc.) and by appropriately referring to prior art documents, etc. as necessary.

[0045] In the following Examples 1 and 2, detailed descriptions will be omitted as appropriate, for example, by referring to the same reference numerals for similar contents. Also, in Fig. 2 described later, the dimension t1, clearance dimension C, dimensional tolerance ΔT, and gap dimension α are each exaggerated for convenience.

[0046] 1 to 5, a schematic configuration example of a vacuum interrupter 1A employing a bearing structure according to Example 1 will be described. This vacuum interrupter 1A includes a vacuum vessel 1 having an insulating cylindrical body 10 sealed at one axial end by a fixed flange 1a and sealed at the other axial end by a movable flange 1b.

[0047] In the case of the cylindrical main body 10 shown in Figure 1, it mainly comprises a cylindrical intermediate shield (arc shield) 20 that surrounds the outer periphery of the fixed electrode 14a and movable electrode 14b described below, a fixed side insulating portion 21a that is connected to one side of the intermediate shield 20 in the axial direction, and a movable side insulating portion 21b that is connected to the other side of the intermediate shield 20 in the axial direction.

[0048] In addition, the central portion of the intermediate shield 20 is provided with a fixed side extension portion 20a extending from the central portion to one side in the axial direction and overlapping with the inner side of the fixed side insulating portion 21a, and a movable side extension portion 20b extending from the central portion to the other side in the axial direction and overlapping with the inner side of the movable side insulating portion 21b.

[0049] The fixed side flange 1a has a disk-shaped portion 11a and an outer peripheral edge portion 12a that extends from the outer periphery of the disk-shaped portion 11a to the other side in the axial direction and is supported by the end face 2aa of the fixed side insulating portion 21a, and has an overall cylindrical structure with a bottom.

[0050] A columnar fixed-side current-carrying shaft 13a is provided at the center of the disk-shaped portion 11a 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 ). A fixed electrode 14a is supported at the end of the fixed-side current-carrying shaft 13a on the other axial side.

[0051] The movable side flange 1b has a disk-shaped portion 11b and an outer peripheral edge portion 12b that extends from the outer periphery of the disk-shaped portion 11b to one side in the axial direction and is supported by the end face 2bb of the movable side insulating portion 21b, and has an overall cylindrical shape with a bottom.

[0052] A flange through hole 3 is provided in the center of the disc-shaped portion 11b, and extends axially through the center. A columnar movable-side current-carrying shaft 13b is inserted into the flange through hole 3 and extends axially.

[0053] A movable electrode 14b is supported at one axial end of the movable current-carrying shaft 13b. The one axial end of the movable current-carrying shaft 13b (the movable electrode 14b side) is supported on the movable flange 1b inside the vacuum vessel 1 via a cylindrical bellows 15 that is axially expandable and contractible and is arranged coaxially with the movable current-carrying shaft 13b. In the case of the movable current-carrying shaft 13b shown in FIG. 1, a cylindrical bellows shield 16 is provided to cover and surround the outer periphery of the bellows 15.

[0054] In the flange through hole 3, a bearing 4 capable of guiding the movable side current shaft 13b in the axial direction in a non-rotatable state is inserted into the flange through hole 3 (inserted so as to be positioned coaxially on the outer periphery of the movable side current shaft 13b in the flange through hole 3).

[0055] This bearing 4 has a structure that allows it to be inserted into the flange through hole 3 with elastic deformation (for example, a structure that has a flange-shaped portion 5 and a cylindrical wall portion 6 described below, and can be inserted using a so-called snap-fit ​​structure), and is installed so that it cannot rotate relative to the flange through hole 3.

[0056] With the vacuum interrupter 1A configured as described above, the movable-side current-carrying shaft 13b (and the movable electrode 14b) can be moved while being guided in the axial direction while maintaining the vacuum state inside the vacuum vessel 1 (specifically, the outer periphery of the bellows 15 inside the vacuum vessel 1), and the movable electrode 14b can be moved toward or away from the fixed electrode 14a (contact 14) in accordance with the movement of the movable-side current-carrying shaft 13b.

[0057] The materials, shapes, etc. of each component of the vacuum interrupter 1A, as well as the processing and assembly methods of each component, can be appropriately applied in various ways depending on the intended use of the vacuum interrupter 1A, etc.

[0058] For example, among the components of the vacuum interrupter 1A, an insulating material (e.g., alumina ceramics) may be used for the fixed side insulating portion 21a and the movable side insulating portion 21b, a resin material (e.g., a heat-resistant resin material) may be used for the bearing 4, and a metal material (e.g., stainless steel (SUS304), oxygen-free copper, titanium) may be used for the remaining 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.

[0059] <Configuration example of bearing 4> The bearing 4 has a structure that can be inserted into the flange through-hole 3 with elastic deformation, and can move while guiding the movable-side current-carrying shaft 13 b in the axial direction in an unrotatable state, and various configurations can be applied.

[0060] One example is a structure such as the bearing 4 shown in Figures 1 to 4, which has a flange-shaped portion 5 and a cylindrical wall portion 6 and can be inserted into the flange through-hole 3 with elastic deformation (a structure that can be inserted with a so-called snap-fit ​​structure).

[0061] The flange-shaped portion 5 is annular in shape with a diameter larger than the opening diameter of the opening 3b on the other axial side of the flange through-hole 3, and extends along the opening edge surface 31b of the opening 3b.

[0062] The cylindrical wall portion 6 is cylindrical and extends from the inner peripheral edge portion 51 of the flange portion 5 to one side in the axial direction, and has a shape that allows it to be inserted into the flange through-hole 3 from the other side in the axial direction toward the one side in the axial direction. The inner peripheral surface 6a of the cylindrical wall portion 6 has a shape that allows the movable-side current-carrying shaft 13b to be inserted into the inner peripheral surface side, and that guides the inserted movable-side current-carrying shaft 13b in the axial direction.

[0063] Claw portions 61 are formed on the outer peripheral surface 6b of the cylindrical wall portion 6 so as to protrude radially outward from the cylindrical wall portion 6. The outer diameter of the portion of the cylindrical wall portion 6 where the claw portions 61 are formed is larger than the opening diameter of the opening 3a of the flange through-hole 3 on one side in the axial direction.

[0064] Furthermore, when the dimension between the flange-shaped portion 5 and the claw portion 61 is L and the axial dimension of the flange through-hole 3 (which is the same dimension as the thickness of the disk-shaped portion 11b in the figure) is T, it is assumed that the following formula (1) is satisfied.

[0065] L≧T ... (1) The cylindrical wall portion 6 is provided with slit holes 62 that penetrate the cylindrical wall portion 6 in the radial direction. These slit holes 62 extend in the axial direction and open to the other side in the axial direction, and a plurality of them (four in FIGS. 3 and 4 ) are formed at predetermined intervals in the circumferential direction of the cylindrical wall portion 6. As a result, in the four cylindrical wall pieces 60 that are located between each of the slit holes 62 in the circumferential direction of the cylindrical wall portion 6, one axial side of each of the cylindrical wall pieces 60 is configured to be elastically deformable in the radial direction.

[0066] When the cylindrical wall portion 6 of such a bearing 4 is inserted through the flange through-hole 3 from the other axial side toward one axial side, one axial side of each cylindrical wall piece 60 elastically deforms radially inward while the claw portions 61 of the cylindrical wall portion 6 are positioned within the flange through-hole 3. Then, after the claw portions 61 of the cylindrical wall portion 6 are released from the flange through-hole 3 toward one axial side, the cylindrical wall piece 60 elastically returns to its original position.

[0067] As a result, the bearing 4 engages with the flange through hole 3 in a position in which the flange-shaped portion 5 and the claw portion 61 clamp the movable side flange 1b (the hole wall of the flange through hole 3) in the axial direction, making it easier to maintain this engaged state.

[0068] In the case of the claw portion 61 in the figure, the shape protrudes radially outward as it approaches the other axial side from one axial side. Furthermore, the surface of the claw portion 61 on the other axial side is formed flat along the opening edge surface 31a of the opening 3a of the flange through-hole 3. With the claw portion 61 shaped like this, it becomes easier to insert the bearing 4 into the flange through-hole 3, and after the bearing 4 has been inserted and engaged, the engaged state is more easily maintained.

[0069] <Example of a method for assembling bearing 4> The components that create a vacuum state inside the vacuum vessel 1 (in FIG. 1 , the cylindrical main body 10, fixed side flange 1a, movable side flange 1b, bellows 15, movable side current-carrying shaft 13b, etc.; hereinafter, simply referred to as vacuum state components) can be assembled by a vacuum brazing process, but in the case of the bearing 4, if the heat resistance temperature of the bearing 4 is higher than the vacuum brazing temperature, the components may be engaged in a process before the vacuum brazing process or in a process after the vacuum brazing process.

[0070] On the other hand, if the heat resistance temperature of the bearing 4 is lower than the vacuum brazing temperature, the vacuum brazing process and the bearing engagement process can be performed in this order as shown below. First, in the vacuum brazing process, brazing material is appropriately placed in advance at the assembly locations of the vacuum state components, and the vacuum state components are assembled as shown in Figure 1. Then, the assembled vacuum state components are heat-treated in a vacuum furnace and vacuum brazed.

[0071] As a result of this vacuum brazing, the movable side current shaft 13b is inserted into the flange through hole 3 and extends in the axial direction, and one axial side of the movable side current shaft 13b is supported (brazed) to the inside of the vacuum vessel 1 of the movable side flange 1b via the bellows 15.

[0072] Next, in the bearing engagement step, the cylindrical wall portion 6 of the bearing 4 is first positioned to face the other axial side of the movable current-carrying shaft 13b, and then the bearing 4 is fitted into the other axial side of the movable current-carrying shaft 13b. The fitted bearing 4 is then moved to one axial side and inserted into the flange through-hole 3 (inserted into the outer periphery of the movable current-carrying shaft 13b), thereby achieving the engaged state shown in Figures 1 and 2.

[0073] If dimensional tolerances or the like occur in the flange through-hole 3 after the vacuum brazing process described above, the subsequent bearing engagement process may be hindered. In such cases, the bearing 4 may be appropriately designed in advance, taking into account dimensional tolerances and the like, as described below.

[0074] First, the bearing 4 is designed to satisfy the following equations (2) and (3): Δφ is the dimensional tolerance of the diameter of the flange through-hole 3, t1 is the dimension of the claw portion 61 in the protruding direction, C is the clearance dimension between the cylindrical wall portion 6 and the movable-side current-carrying shaft 13b, ΔT is the dimensional tolerance of the dimension T in the axial direction of the flange through-hole 3, and α is the dimension of the gap (for example, an extremely narrow gap) between the opening edge surface 31a of the opening 3a in the flange through-hole 3 and the claw portion 61.

[0075] Δφ<t1<C ... (2) L = T + ΔT + α ... (3) With a bearing 4 designed in this manner, even if dimensional tolerances or the like occur in the flange through-hole 3 after the vacuum brazing process, the bearing engagement process can be carried out appropriately, and the bearing can be engaged with the flange through-hole 3 as desired.

[0076] <Example of a configuration for making the movable-side current-carrying shaft 13b non-rotatable> The configuration for making the movable-side current-carrying shaft 13b non-rotatable relative to the cylindrical wall portion 6 of the bearing 4 is not particularly limited, and various configurations can be applied.

[0077] As an example, a configuration is given in which an outer peripheral flat surface 13d having a shape that follows the tangent plane of the outer peripheral surface 13c is formed on the outer peripheral surface 13c of the movable side current-carrying shaft 13b, and an inner peripheral flat surface 6c having a shape that follows the outer peripheral flat surface 13d is formed at a position on the inner peripheral surface 6a of the cylindrical wall portion 6 opposite the outer peripheral flat surface 13d.

[0078] With this configuration, even if a rotational force acts on the movable side current-carrying shaft 13b, the outer peripheral flat surface 13d and the inner peripheral flat surface 6c abut against each other, thereby suppressing the rotation of the movable side current-carrying shaft 13b (maintaining a non-rotatable state).

[0079] The outer peripheral flat surface 13d and the inner peripheral flat surface 6c may each be provided singly or in plural at predetermined intervals in the circumferential direction. In Fig. 4, two outer peripheral flat surfaces 13d are formed parallel to each other on the outer peripheral surface 13c of the movable-side current-carrying shaft 13b, thereby forming a so-called two-face shape.

[0080] Alternatively, instead of simply providing a plurality of outer circumferential flat surfaces 13d and inner circumferential flat surfaces 6c, they may be provided as appropriate so as to be rotationally symmetrical about the axial direction (180-degree rotational symmetry in FIG. 4). In this case, the insertion posture of the movable-side current-carrying shaft 13b when it is inserted into the bearing 4 will be rotationally symmetrical, which may facilitate the insertion work (positioning, etc.).

[0081] <Configuration Example for Making Bearing 4 Non-Rotatable> There are no particular limitations on the configuration for making the bearing 4 non-rotatable relative to the flange through-hole 3, and various configurations can be applied. For example, it is possible to apply a configuration similar to the configuration for making the movable-side current-carrying shaft 13b non-rotatable (configuration in which the outer peripheral flat surface 13d and the inner peripheral flat surface 6c are formed), but it is also possible to apply a configuration shown in Example 2 described below.

[0082] According to the above-described first embodiment, the bearing 4 can be inserted into the flange through-hole 3 and engaged without using adhesives, bolts, etc., and this engaged state can be easily maintained, which can contribute to improved productivity, etc.

[0083] Next, a description will be given of a second embodiment in which the bearing 4 is made non-rotatable relative to the flange through-hole 3. In this second embodiment, as shown in Fig. 5, a recess 32 is formed in the opening edge surface 31b of the opening 3b of the movable-side flange 1b. In addition, as shown in Figs. 3 and 4, a protrusion 52 having a shape that can be fitted into the recess 32 is formed in the flange-shaped portion 5 of the bearing 4 at a position facing the recess 32.

[0084] According to the configuration in which the recess 32 and the protrusion 52 are formed in this manner, it is possible to engage the bearing 4 with the flange through-hole 3 so that the protrusion 52 fits into the recess 32. If the state in which the protrusion 52 fits into the recess 32 (hereinafter simply referred to as the fitted state) is maintained, even if a rotational force acts on the bearing 4, rotation of the bearing 4 is suppressed (a non-rotatable state is maintained).

[0085] The convex portion 52 may be formed at any position facing the concave portion 32 as described above, but is preferably formed at the base side of the cylindrical wall piece 60 in the flange-shaped portion 5. This allows the cylindrical wall piece 60 to be thickened in accordance with the shape, position, etc. of the convex portion 52, thereby improving the mechanical strength.

[0086] The recess 32 and the protrusion 52 may be provided not only in one piece but also in a plurality of pieces (four pieces each in FIGS. 3 to 5) spaced at predetermined intervals in the circumferential direction.

[0087] Alternatively, instead of simply providing a plurality of recesses 32 and protrusions 52, they may be provided as appropriate so as to be rotationally symmetrical about the axial direction (90-degree rotational symmetry in FIG. 4 ). In this case, the engagement posture of the bearing 4 when engaging with the flange through-hole 3 will have rotational symmetry, which may facilitate the engagement work (positioning, etc.).

[0088] Furthermore, if dimensional tolerances or the like occur in the flange through-hole 3 after the vacuum brazing process described above, it may be possible that the state in which the convex portion 52 is fitted into the concave portion 32 cannot be maintained. In such cases, the bearing 4 may be appropriately designed to satisfy the following formula (4). Note that t2 in the following formula (4) represents the dimension of the convex portion 52 in the protruding direction.

[0089] t2>ΔT+α...(4) With a bearing 4 designed in this manner, even if dimensional tolerances or the like occur in the flange through hole 3 after the vacuum brazing process, the bearing engagement process can be carried out appropriately, making it easier to maintain the fit of the convex portion 52 into the concave portion 32.

[0090] According to the second embodiment described above, in addition to the same effects as those of the first embodiment, the following can be said: Since the flange through-hole 3 itself does not need to be designed taking into account the non-rotation state, it is possible to contribute to cost reduction by, for example, making the flange through-hole 3 into a shape that is relatively easy to manufacture (for example, a circular shape).

[0091] 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.

[0092] 1A...vacuum interrupter, 1...vacuum vessel, 1a...fixed flange, 1b...movable flange, 13b...movable current-carrying shaft, 14a...fixed electrode, 14b...movable electrode, 15...bellows, 3...flange through-hole, 32...recess, 4...bearing, 5...flange-shaped portion, 52...projection, 6...cylindrical wall portion, 60...cylindrical wall piece, 61...claw portion, 62...slit hole

Claims

1. A bearing structure for a movable-side current-carrying shaft, which supports a movable electrode of a fixed electrode and a movable electrode disposed opposite each other in the axial direction of an insulating cylindrical body within a vacuum vessel having the cylindrical body, so that the movable electrode is movable in the axial direction, the cylindrical body having a fixed side that is one side in the axial direction sealed by a fixed side flange and a movable side that is the other side in the axial direction sealed by a movable side flange, the movable side flange having a flange through hole penetrating the movable side flange in the axial direction, the movable side current-carrying shaft being inserted into the flange through hole and extending in the axial direction, the one side of the movable side current-carrying shaft being supported on the inside of the vacuum vessel of the movable side flange via a bellows that is expandable and contractible in the axial direction, the flange through hole having a bearing that guides the movable side current-carrying shaft in the axial direction in a non-rotatable state and is provided in the flange through hole in a non-rotatable state relative to the flange through hole, the bearing being a flange-shaped portion having a ring-like shape with a diameter larger than the opening diameter of the opening on the other side of the flange through hole and extending along the opening edge surface of the opening on the other side; and a cylindrical wall portion having a cylindrical shape extending from an inner peripheral edge of the flange-shaped portion to the one side, which is inserted into the flange through hole from the other side toward the one side and guides the movable-side current-carrying shaft inserted into the inner peripheral surface of the cylindrical portion in the axial direction, wherein the cylindrical wall portion has claw portions formed on an outer peripheral surface of the cylindrical wall portion that protrude radially outward of the cylindrical wall portion, a plurality of slit holes are formed at predetermined intervals in the circumferential direction of the cylindrical wall portion, the slit holes penetrating the cylindrical wall portion in the radial direction and extending in the axial direction and opening to the one side, and each cylindrical wall piece that is a portion of the cylindrical wall portion between each of the slit holes in the circumferential direction is elastically deformable in the radial direction, The bearing structure for a movable current-carrying shaft is characterized in that an outer diameter of the portion of the cylindrical wall where the claw portion is formed is larger than an opening diameter of the opening on the one side of the flange through-hole, and the following formula (1) is satisfied, where L is the dimension between the flange-shaped portion and the claw portion, and T is the dimension of the flange through-hole in the axial direction. L≧T (1) 2. The bearing structure for the movable current-carrying shaft according to claim 1, characterized in that the following formulas (2) and (3) are satisfied, where the dimensional tolerance of the diameter of the flange through-hole is Δφ, the dimension of the claw portion in the protruding direction is t1, the clearance dimension between the cylindrical wall portion and the movable current-carrying shaft is C, the dimensional tolerance related to T is ΔT, and the dimension of the gap between the opening edge surface of the opening on one side and the claw portion is α. Δφ<t1<C ... (2) L = T + ΔT + α ... (3) 3. A bearing structure for a movable-side current-carrying shaft as described in claim 1, characterized in that the claw portion has a shape that protrudes radially outward as it approaches the other side from the one side, and the surface of the claw portion on the other side is formed flat along the opening edge surface of the opening on the one side of the flange through-hole.

4. A bearing structure for a movable current-carrying shaft as described in claim 1, characterized in that at least one recess is formed on the opening edge surface of the opening on the other side, and a protrusion that can be fitted into the recess is formed on the flange-shaped portion at a position opposite the recess.

5. A bearing structure for a movable current-carrying shaft as described in claim 4, characterized in that the recesses are formed in a plurality at predetermined intervals in the circumferential direction on the opening edge surface of the other opening, and are formed so as to be rotationally symmetrical on the opening edge surface when the axial direction is taken as the axis of symmetry.

6. A bearing structure for a movable current-carrying shaft according to claim 4, wherein said protrusion is formed on the base side of said cylindrical wall piece in said flange-shaped portion.

7. The bearing structure for the movable side current-carrying shaft according to claim 4, characterized in that the following formula (4) is satisfied, where the dimensional tolerance for T is ΔT, the dimension of the gap between the opening edge surface of the opening on one side and the claw portion is α, and the dimension in the protruding direction of the convex portion is t2. t2>ΔT+α (4) 8. A vacuum interrupter having a bearing structure for a movable conductive shaft according to any one of claims 1 to 7.

9. A method for manufacturing a vacuum interrupter as described in claim 8, comprising: a vacuum brazing process for brazing one side of the movable current shaft to the inside of the vacuum vessel of the movable flange via the bellows while the movable current shaft is inserted into the flange through hole and extended in the axial direction; and a bearing engagement process for fitting the bearing into the flange through hole from the other side thereof after the vacuum brazing process.

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