Bushing structure and electrical equipment

Abstract

To provide a technique capable of contributing to suppression of the number of components of a bushing structure, and facilitation of the assembly.SOLUTION: A bushing structure includes: a cylindrical part 31 coaxially positioned at an outer peripheral side of a porcelain tube conductor 2 in a grounding shield 3; and an extension part 32 having a shape extending to an outside in the radial direction of a porcelain tube 1 from the cylindrical part 31, and disposed between a porcelain tube side flange 4 and a vessel side flange 6. A notched recess 7 of a shape permitting receiving at least an extension direction end part 35 side in the extension part 32 is disposed in one of both of a porcelain tube side opposite surface inner peripheral side portion 4a of an opposite surface 40 of the porcelain tube side flange 4, and a vessel side opposite surface inner peripheral side portion 6a of an opposite surface 60 of the vessel side flange 6. In the extension part 32, at least the extension direction end part 35 side of the extension part in a state of being supported by the porcelain tube side opposite surface inner peripheral side portion 4a is received by the notched recess.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bushing structure and an electric device, and more particularly to a technique applicable when connecting an electric device such as a circuit breaker or a switchgear to a main circuit. [Background technology]

[0002] For example, it is known that electrical equipment such as a circuit breaker or a switchgear in an electric power facility is electrically connected to a main circuit or the like via a bushing (gas insulating bushing or the like).

[0003] The bushing structure shown in Patent Documents 1 and 2 includes a conductor inside a cylindrical porcelain tube that is arranged to extend along the axis of the porcelain tube (hereinafter simply referred to as the porcelain tube axis), and a cylindrical grounding shield that is arranged coaxially on the outer periphery of the conductor inside the porcelain tube.

[0004] In addition, a porcelain tube side flange is provided at one opening (hereinafter simply referred to as one-side opening) in the direction of both ends of the porcelain tube axis in the porcelain tube (hereinafter simply referred to as the porcelain tube both end direction), and a container side flange is provided at a bushing communication port portion that can communicate with the one-side opening in an electrical equipment container (for example, a container such as a grounded tank that can accommodate electrical equipment elements such as a vacuum interrupter or a circuit breaker (including a mode in which compressed air or the like is blown onto an arc generating part when the circuit is opened); hereinafter simply referred to as the container), and the porcelain tube side flange and the container side flange are configured to be flange-joined to each other.

[0005] In the case of the ground shield of Patent Document 1, it is configured to be supported by a flange dedicated to the ground shield (flange indicated by reference symbol 8 in Patent Document 1) interposed between the porcelain tube flange and the container flange.

[0006] The ground shield of Patent Document 2 is configured to be supported by a flange on the container side (the flange designated by reference symbol 5A in Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 9-27225 [Patent Document 2] Japanese Patent Application Publication No. 7-21861 Summary of the Invention [Problem to be solved by the invention]

[0008] The bushing structure shown in Patent Document 1 requires a flange dedicated to the ground shield in addition to the porcelain tube flange and the container flange, which increases the number of parts, and therefore increases the number of assembly steps, which may lead to an increase in the size, complexity, and cost of the structure.

[0009] In the bushing structure shown in Patent Document 2, the container flange and the porcelain tube flange are flange-joined in a state where the ground shield is supported on the container flange in advance, and one opening of the porcelain tube is communicated with the bushing communication opening. For this reason, for example, in a configuration in which the ground shield is disposed close to the inner peripheral surface of the porcelain tube, the inner peripheral surface of the porcelain tube and the ground shield are likely to interfere with each other (contact, collision, positional deviation, etc.) when the flanges are joined. There is a risk that assembling the bushing structure while suppressing such interference between the two will be complicated and difficult (the flange joining work will be difficult).

[0010] The present invention has been made in consideration of the technical problems described above, and has an object to provide a technique that can contribute to reducing the number of parts in a bushing structure and facilitating assembly. [Means for solving the problem]

[0011] One embodiment of the bushing structure according to the present invention includes a cylindrical porcelain tube, a porcelain tube inner conductor provided in the porcelain tube so as to extend along the axis of the porcelain tube, a cylindrical ground shield provided in the porcelain tube coaxially on the outer periphery of the porcelain tube inner conductor, an annular porcelain tube side flange provided at an opening on one side of the axial direction of the porcelain tube, and an annular container side flange provided at a bushing communication port capable of communicating with the opening of a container of an electrical device and flange-joined to the porcelain tube side flange. The ground shield includes a cylindrical portion located coaxially on the outer periphery of the porcelain tube inner conductor, and an extension portion extending from the cylindrical portion to the outside in the radial direction of the porcelain tube and interposed between the porcelain tube side flange and the container side flange. A notched recess is provided on one of an inner peripheral portion of the porcelain tube side facing surface of the porcelain tube side flange, which is on the inside in the radial direction, and an inner peripheral portion of the container side facing surface of the porcelain tube side flange, which is on the inside in the radial direction, of the surface of the container side flange that faces the porcelain tube side flange. The notched recess is open to the other of the two sides and to the axis center side, and has a shape that extends along the circumferential direction of the axis center, and the extending portion is supported by the inner peripheral portion of the porcelain tube side facing surface, and at least the extending direction end side of the extending portion is received in the notched recess.

[0012] Moreover, the extension portion is supported by being fastened to the inner circumferential side of the opposing surface on the porcelain tube side via a shield fastening member that can fasten the extension portion to the inner circumferential side of the opposing surface on the porcelain tube side, and the shield fastening member has a protruding portion that protrudes from the extension portion toward the inner circumferential side of the opposing surface on the container side when the extension portion is fastened and fixed, and the notch recess may be shaped to receive at least the extension direction end side of the extension portion and the protruding portion of the shield fastening member when the extension portion is fastened and fixed.

[0013] The container flange and the bushing communication opening may be separate bodies.

[0014] The electrical wiring may further comprise a current detector having an annular core through which the bushing communication opening portion penetrates, and capable of detecting a current flowing through the conductor in the porcelain tube.

[0015] It may also be characterized in that the porcelain tube side flange outer circumferential side portion, which is the radially outer side of the porcelain tube side flange, and the container side flange outer circumferential side portion, which is the radially outer side of the container side flange, are fastened and fixed by a flange fastening member capable of fastening the porcelain tube side flange outer circumferential side portion and the container side flange outer circumferential side portion.

[0016] One aspect of the electrical equipment is an electrical equipment provided with any of the above-mentioned bushing structures, characterized in that at least one of a vacuum interrupter and a circuit breaker is electrically connected to the conductor inside the porcelain tube while being housed in the container. Effect of the Invention

[0017] As described above, the present invention can contribute to reducing the number of parts of a bushing and facilitating assembly. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic configuration diagram (a cross-sectional view taken along the axis of a porcelain insulator tube) for explaining a bushing structure according to a first embodiment. FIG. [Diagram 2] FIG. 2 is an enlarged schematic diagram of a main part of FIG. 1. [Diagram 3] 3 is a schematic diagram showing an enlarged view of the main parts of FIG. 2 ((a) is a diagram showing the state in which the porcelain tube side flange 4 and the container side flange 6 are flange-joined, and (b) is a diagram showing only the porcelain tube side flange 4 and the container side flange 6 before the flange joining). [Figure 4] FIG. 11 is a schematic configuration diagram (a cross-sectional view taken along the axis of a porcelain insulator tube) for explaining a bushing structure according to a second embodiment. [Diagram 5] FIG. 5 is an enlarged schematic diagram of a main part of FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The bushing structure and electrical equipment of the embodiments of the present invention are completely different from configurations such as those in Patent Document 1, in which the ground shield is supported on a flange dedicated to the ground shield, or those in Patent Document 2, in which the ground shield is supported on a container side flange.

[0020] That is, in this embodiment, the ground shield has a cylindrical portion located coaxially on the outer periphery of the porcelain tube inner conductor, and an extension portion (hereinafter simply referred to as the shield extension portion) extending outward from the cylindrical portion in the radial direction of the porcelain tube (hereinafter simply referred to as the porcelain tube radial direction) and interposed between the porcelain tube side flange and the container side flange.

[0021] In addition, a notched recess having a shape capable of accepting at least the extension direction end side of the shield extension portion is provided in one of the following portions: a portion of the surface of the porcelain tube side flange facing the container side flange that is on the inside in the porcelain tube radial direction (hereinafter simply referred to as the inner circumferential side portion of the porcelain tube side facing surface) and a portion of the surface of the container side flange facing the porcelain tube side flange that is on the inside in the porcelain tube radial direction (hereinafter simply referred to as the inner circumferential side portion of the container side facing surface).

[0022] The shield extension is supported by the inner circumferential side of the facing surface of the porcelain insulator tube, and at least the end side of the shield extension in the extending direction is received in the cutout recess.

[0023] According to the configuration of this embodiment, a flange dedicated to the ground shield is not required, which reduces the number of parts and assembly steps, and contributes to a smaller, simpler, and less costly structure.

[0024] In addition, when the porcelain tube flange is flange-joined to the container flange with the shield extension supported on the inner peripheral side of the porcelain tube facing surface in advance, at least the end side of the shield extension in the extending direction can be received in the notched recess. Therefore, even when the porcelain tube flange is flange-joined to the container flange, the shield extension and the container flange can be prevented from interfering with each other, and further, the inner peripheral surface of the porcelain tube and the ground shield can be prevented from interfering with each other (contact, collision, positional deviation, etc.). This makes it easy to assemble the bushing structure as desired (easy flange joining work).

[0025] The bushing structure and electrical equipment of this embodiment only need to be configured in such a way that at least the extension direction end side of the shield extension portion can be received within the cutout recess while the shield extension portion is supported on the inner circumferential side of the facing surface of the porcelain tube as described above, and various design modifications are possible.

[0026] In other words, it is possible to appropriately apply technical common sense in various fields (e.g., bushings, circuit breakers, switchgears, power equipment, etc.) and, as necessary, to appropriately refer to prior art documents and the like to modify the design, and examples 1 and 2 below are given as examples.

[0027] Example 1 [Example of a general configuration of a bushing structure] 1 to 3 are schematic diagrams illustrating a bushing structure according to a first embodiment, showing an example in which the bushing structure is provided in a container 10 of an electric device such as a circuit breaker or a switchgear.

[0028] In the bushing structure shown in Figures 1 to 3, a conductor 2 inside a cylindrical insulating porcelain tube 1 is provided so as to extend along the axis, and a cylindrical grounding shield 3 is further provided so as to be positioned coaxially on the outer periphery of the conductor 2 inside the porcelain tube.

[0029] In the porcelain tube 1, a circular tube side flange 4 is provided at one side opening 11 located on one side (the lower side in the figure) of both ends of the porcelain tube, and a circular connection flange 13 is provided at an opening (hereinafter simply referred to as the other side opening) 12 on the other side (the upper side in the figure) of both ends of the porcelain tube.

[0030] The other opening 12 is sealed by providing a conductive sealing end plate 14 on the connection flange 13, which makes it possible to suppress leakage of, for example, the insulating gas sealed in the porcelain tube 1. The sealing end plate 14 is electrically connected, for example, to the main circuit side of an electric power facility not shown in the figure.

[0031] The first opening 11 communicates with the bushing communication port 5 of the container 10 by flange-joining the porcelain tube side flange 4 to a circular container side flange 6 provided at the bushing communication port 5 .

[0032] [An example of porcelain tube 1] The porcelain tube 1 may be, for example, a tube made of insulating polymer material or ceramic material and appropriately molded into a cylindrical shape. In the case of the porcelain tube 1 shown in Figs. 1 to 3, the outer circumferential surface of the cylindrical inner wall portion 1a made of a polymer material is covered with a cylindrical outer circumferential wall 1b made of the same polymer material to form a two-layer structure, but the present invention is not limited to this. For example, it may have a single-layer structure as shown in Figs. 4 and 5 described later. In addition, the outer circumferential surface side of the porcelain tube 1 may be formed into a bellows shape by providing a plurality of annular fins 1c extending in the circumferential direction along the outer circumferential surface of the outer circumferential wall 1b, as in the outer circumferential wall 1b shown in Figs. 1 to 3.

[0033] [An example of conductor 2 inside a ceramic insulator tube] The conductor 2 in the porcelain tube may be, for example, suitably formed into a wire shape using a conductive material. In the case of the conductor 2 in the porcelain tube shown in Figures 1 to 3, an end 21 on one side in both end directions is joined to a conductor in the container 10 (for example, the conductor 10b in the container in Figures 4 and 5 described later), and an end 22 on the other side in both end directions is joined to and supported by the center of the sealed end plate 14. This allows electrical equipment elements such as a vacuum interrupter or circuit breaker (not shown) arranged in the container 10 to be electrically connected to, for example, the main circuit side of a power facility (not shown).

[0034] [An example of a ground shield 3] The ground shield 3 may be, for example, a conductive material that is appropriately formed into a cylindrical shape, etc. The ground shield 3 shown in Fig. 1 to Fig. 3 has a cylindrical portion 31 that is coaxially positioned with respect to the outer periphery of the porcelain tube inner conductor 2, and a flange-shaped shield extension portion 32 that extends from the cylindrical portion 31 to the outside in the porcelain tube radial direction.

[0035] 1 to 3, the shield extension 32 has a shape extending outward in the radial direction of the porcelain insulator tube from the open end 33 on one side of the tubular portion 31 in the direction of both ends of the porcelain insulator tube, but is not limited thereto. For example, the shield extension 32 may have a shape extending outward in the radial direction of the porcelain insulator tube from the center of the tubular portion 31 in the direction of both ends of the porcelain insulator tube.

[0036] Also, in the open end 34 on the other side of the tubular portion 31 in the direction of both ends of the porcelain insulator tube, the end 34a side may be expanded in diameter outward in the porcelain insulator tube radial direction and curved as shown in the figure to further relax the electric field at the open end 34. Specifically, in the case of the open end 34 in the figure, the end 34a side is expanded in diameter outward in the porcelain insulator tube radial direction, while curving back in the opposite direction to the extension direction of the open end 34 itself (open end 34) and approaching itself.

[0037] The shield extension portion 32 is interposed between the porcelain tube side flange 4 and the container side flange 6, and is supported by the porcelain tube side flange 4. Specifically, the shield extension portion 32 is supported by an inner peripheral side portion 4a of the porcelain tube side opposing surface, which is on the inner side in the porcelain tube radial direction, of the opposing surface 40 of the porcelain tube side flange 4 facing the container side flange 6. In this supported state, at least the extension direction end portion 35 side of the shield extension portion 32 is received in a cutout recess 7 described later.

[0038] In addition, the ground shield 3 and the inner peripheral surface of the porcelain tube 1 are appropriately set so as not to come into contact with each other. Specifically, the dimensions of the ground shield 3 (e.g., the dimensions in the radial direction of the porcelain tube) and the support position of the shield extension portion 32 with respect to the porcelain tube side flange 4 are appropriately set to form a small gap between the ground shield 3 and the inner peripheral surface of the porcelain tube 1 as shown in the figure.

[0039] [An example of the porcelain tube flange 4, container flange 6, and connection flange 13] The porcelain tube flange 4, the container flange 6, and the connection flange 13 may each be appropriately formed into a circular ring shape using a conductive material, for example.

[0040] 1 to 3, the porcelain tube side flange 4 has a flange portion 41 extending from one side opening 11 outward in the porcelain tube radial direction and extending along the circumferential direction of the porcelain tube axis, and a tubular portion 42 extending from the inner peripheral side of the flange portion 41 along the outer peripheral surface of the porcelain tube 1 to the other side in the direction of both ends of the porcelain tube. A reduced diameter portion 43 having a smaller diameter than the inner peripheral surface of the tubular portion 42 is formed on the inner peripheral side of the flange portion 41. As a result, the one side opening 11 of the porcelain tube 1 is fitted between the inner peripheral surface of the tubular portion 42 and the reduced diameter portion 43 (on the inner angle side) and supported.

[0041] The connection flange 13 has a similar configuration to the porcelain tube flange 4, and includes a flange portion 13a extending from the other side opening 12 to the outside in the porcelain tube radial direction and extending along the circumferential direction of the porcelain tube axis, and a cylindrical portion 13b extending from the inner peripheral side of the flange portion 13a to one side in the porcelain tube end direction along the outer peripheral surface of the porcelain tube 1. A reduced diameter portion 13c having a smaller diameter than the inner peripheral surface of the cylindrical portion 13b is formed on the inner peripheral side of the flange portion 13a. As a result, the other side opening 12 of the porcelain tube 1 is fitted between the inner peripheral surface of the cylindrical portion 13b and the reduced diameter portion 13c (on the inner angle side) and supported.

[0042] The container side flange 6 has a flange portion 61 that extends inward and outward in the radial direction of the insulator tube from the opening end 51 on the other side of the bushing communication port portion 5 in the direction of both ends of the insulator tube and extends circumferentially around the axis of the insulator tube.

[0043] A notched recess 7 is provided on an inner peripheral side portion 6a of the container-side flange 6 facing the porcelain tube side flange 4, which is on the inside in the porcelain tube radial direction of the container-side facing surface. This notched recess 7 has a shape capable of receiving at least the extension direction end 35 of the shield extension portion 32 in a state in which the shield extension portion 32 is supported by the porcelain tube side flange 4. The notched recess 7 may have a shape capable of receiving at least the extension direction end 35 of the shield extension portion 32 as described above, and can be set appropriately (for example, the dimensions in the directions of both ends of the porcelain tube and the dimensions in the porcelain tube radial direction can be set appropriately).

[0044] For example, as shown in Fig. 2, when the shield extension 32 is fastened and supported to the inner peripheral side part 4a of the surface facing the porcelain tube by a fastening member 36 having a bolt 36a and a part of the fastening member 36 (such as a screw head 36b in the figure) protrudes from the shield extension 32 to one side in the direction of both ends of the porcelain tube, the cutout recess 7 may have a shape capable of receiving at least the extension direction end 35 side of the shield extension 32 and the protruding part (hereinafter simply referred to as the protruding part). Specifically, in the case of the cutout recess 7 in Figs. 1 to 3, a receiving hole 71 having a shape capable of receiving the protruding part of the fastening member 36 is provided at a position facing the fastening member 36 on the inner peripheral surface of the cutout recess 7.

[0045] [An example of container 10] The container 10 may be, for example, a metal material that is appropriately formed into a housing shape or the like (for example, a grounded tank, etc.) In the container 10, at least one electrical device element (not shown) is housed, for example, a vacuum interrupter or disconnector (including a device in which compressed air or the like is blown to an arc generating part to extinguish an arc when the circuit is opened) that is applied to electrical devices such as a circuit breaker (including a gas circuit breaker, etc.) and a switchgear, and an insulating gas is sealed inside.

[0046] The bushing communication port 5 provided in the container 10 can be appropriately formed according to the intended electric device. The bushing communication port 5 shown in Fig. 1 to Fig. 3 has a cylindrical side wall 50, and a container side flange 6 is integrally formed with an opening end 51 on the other side of the side wall 50 in the direction of both ends of the porcelain tube.

[0047] 〔others〕 The elements of the bushing structure of Example 1 can be assembled appropriately by joining and fixing them using various joining means (adhesives, fastening members, adhesion, welding, etc.) or by molding them as a single piece, or by arranging sealing material in predetermined positions (for example, arranging sealing material S as shown in Figures 4 and 5 described below).

[0048] The joining means is not particularly limited, and any means suitable for fixing each element of the bushing structure may be used.

[0049] 1 to 3, for example, the porcelain tube side flange 4 and the connection flange 13 are joined and fixed to the porcelain tube 1 (one side opening 11, the other side opening 12) via an adhesive (not shown). In addition, the connection flange 13 and the sealing end plate 14 are both fastened and fixed at their outer peripheries by fastening members 15 having bolts 15a and nuts 15b.

[0050] The porcelain tube side flange 4 and the container side flange 6 are both fastened and fixed at their outer peripheries (the porcelain tube side flange outer periphery side portion 4b and the container side flange outer periphery side portion 6b) by fastening members 16 having bolts 16a.

[0051] According to the above-described first embodiment, a dedicated flange for the ground shield as in Patent Document 1 is not required, which reduces the number of parts and assembly steps, and contributes to miniaturization, simplification, and cost reduction of the structure.

[0052] Furthermore, even if the shield extension 32 is supported in advance on the porcelain tube flange 4 and the porcelain tube flange 4 is flange-joined to the container flange 6, at least the extension direction end 35 side of the shield extension 32 can be received in the cutout recess 7. This makes it possible to prevent interference between the shield extension 32 and the container flange 6, and further prevents interference (contact, collision, misalignment, etc.) between the inner peripheral surface of the porcelain tube 1 and the ground shield 3. As a result, the bushing structure can be easily assembled as desired.

[0053] Example 2 4 and 5 are schematic diagrams for explaining the bushing structure according to the second embodiment, and show an example of the case where the bushing structure is provided in the container 10, similar to the first embodiment. Note that the same reference numerals are used to refer to the same contents as the first embodiment, and detailed explanations thereof will be omitted as appropriate.

[0054] [An example of the bushing communication port 5 and the current detector 8] The bushing communication port 5 shown in Figs. 4 and 5 is configured as a separate body from the container side flange 6, and is configured so that a current detector 8 can be installed therein.

[0055] Specifically, the side wall 50 of the bushing communication opening portion 5 stands on the opening edge of a through hole 10c formed in the peripheral wall 10a of the container 10.

[0056] The current detector 8 has an annular core 80 capable of detecting a current flowing on the axial center side. The annular core 80 is disposed between the container 10 and the open end 51 on the outer periphery side of the side wall 50, with the side wall 50 penetrating the axial center side of the annular core 80.

[0057] The container side flange 6 is supported on the open end 51 of the side wall 50 via an annular connection adapter 52 provided on the open end 51. In the case of the container side flange 6 shown in Figures 4 and 5, fastening holes 82 for fastening members (not shown) are provided on the outer periphery of the container side flange 6 so as to support a protective cover 81 capable of covering the outer periphery of the annular core 80.

[0058] 〔others〕 As with Example 1, each element of the bushing structure of Example 2 can be joined and fixed using various joining means (adhesives, fastening members, adhesion, welding, etc.) or molded into one piece, or can be assembled appropriately by disposing sealing material S in a predetermined position, etc.

[0059] 4 and 5, for example, the sealing end plate 14 is provided with a seal groove 14b extending in the circumferential direction of the porcelain tube axis on a joining surface 14a with the connection flange 13. The sealing end plate 14 with a seal material S such as an O-ring disposed in the seal groove 14b is joined and fixed to the connection flange 13 via an adhesive (not shown).

[0060] Moreover, the container side flange 6 is fastened and fixed to the connection adaptor 52 by a fastening member 53 having a bolt 53a.

[0061] 4 and 5, a receiving hole 72 having a shape capable of receiving the screw head 53b of the bolt 53a is provided at the fastening position of the fastening member 53 on the inner peripheral surface of the cutout recess 7. As a result, when the container side flange 6 and the connection adapter 52 are fastened with the fastening member 53, the screw head 53b of the bolt 53a can be received in the receiving hole 72, so that, for example, interference between the shield extension 32 and the screw head 53b can be prevented.

[0062] In addition, a seal groove 62 extending circumferentially around the porcelain tube axis is provided on the opposing surface 60 of the container side flange 6 at a position between the cutout recess 7 and the fastening member 16, and a seal material S is disposed in the seal groove 62.

[0063] Further, a seal groove 64 extending along the circumferential direction of the porcelain tube axis is provided on a joint surface 63 of the container side flange 6 with the connection adaptor 52, and a seal material S is disposed in the seal groove 64.

[0064] In addition, in Figs. 4 and 5, the positional relationship between the seal groove (and seal material S) 64 and the fastening member 53 is depicted as being interchanged, but either positional relationship may be applied.

[0065] According to the above-described second embodiment, in addition to the same effects as those of the first embodiment, the following can be said. That is, since the bushing communication port 5 and the container side flange 6 are configured separately, the annular core 80 of the current detector 8 can be appropriately disposed on the outer periphery of the bushing communication port 5 before joining the two. This allows the annular core 80 to have an inner diameter smaller than the outer diameter of the container side flange 6, which may contribute to the miniaturization, simplification, and cost reduction of the bushing structure.

[0066] 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.

[0067] For example, the cutout recess 7 may be formed on the inner peripheral portion 4a of the porcelain tube side facing surface of the facing surface 40, instead of on the inner peripheral portion 6a of the container side facing surface of the facing surface 60 as shown in Figures 1 to 5. Even in this case, the porcelain tube side flange 4 can be flange-joined to the container side flange 6 with the shield extension portion 32 supported on the porcelain tube side flange 4 in advance (supported on the inner peripheral surface of the cutout recess 7), and at least the extension direction end portion 35 of the shield extension portion 32 can be received in the cutout recess 7. This makes it possible to achieve the same effects as those of the first and second embodiments. [Explanation of symbols]

[0068] 1...Insulator 2...Conductor inside the ceramic tube 3: Ground shield; 32: Extension; 35: Extension direction end 4...Porcelain tube side flange 5...Bushing connection port 6…Housing side flange 7…Notch recess 8…Current detector 10...Container (grounded tank, etc.)

Claims

1. A cylindrical porcelain tube; a conductor in the porcelain tube provided within the porcelain tube so as to extend along an axis of the porcelain tube; a cylindrical ground shield provided coaxially on an outer periphery of the conductor in the porcelain bushing; an annular porcelain tube side flange provided at an opening on one side of the porcelain tube in a direction toward both ends of the axis; a ring-shaped container-side flange provided in a bushing communication port capable of communicating with the opening in a container of an electric device and flange-joined to the porcelain tube-side flange; having The ground shield includes: a cylindrical portion located coaxially on an outer circumferential side of the porcelain tube inner conductor; an extension portion extending from the cylindrical portion to an outer side in a radial direction of the porcelain tube and interposed between the porcelain tube side flange and the container side flange; having a notched recess is provided on an inner peripheral portion of the container-side facing surface of the porcelain tube-side flange, the inner peripheral portion being on the radially inner side of the surface of the container-side flange facing the porcelain tube-side flange, and a notched recess is provided on an inner peripheral portion of the container-side facing surface of the porcelain tube-side flange, the inner peripheral portion being on the radially inner side of the surface of the container-side flange facing the porcelain tube-side flange, the cutout recess has a shape that opens toward an inner peripheral side portion of the porcelain tube-side facing surface and toward the shaft center and extends along a circumferential direction of the shaft center, A bushing structure characterized in that the extension portion is supported by the inner circumferential side of the opposing surface of the porcelain tube, and at least the extension direction end side of the extension portion is received within the cutout recess.

2. the extension portion is supported by being fastened to the inner peripheral side of the porcelain tube side opposing surface via a shield fastening member capable of fastening the extension portion to the inner peripheral side of the porcelain tube side opposing surface, the shield fastening member has a protruding portion that protrudes from the extension portion toward the inner circumferential side of the container-side facing surface in a state where the extension portion is fastened and fixed, 2. The bushing structure according to claim 1, wherein the cutout recess has a shape capable of receiving at least the end side of the extension portion in the extension direction and a protruding portion of the shield fastening member in a state in which the extension portion is fastened and fixed.

3. 2. The bushing structure according to claim 1, wherein the container side flange and the bushing communication port are separate bodies.

4. 4. The bushing structure according to claim 3, further comprising a current detector having an annular core through which the bushing communication opening portion passes and capable of detecting a current flowing through the conductor inside the porcelain tube.

5. The bushing structure described in claim 1, characterized in that the outer circumferential side portion of the porcelain tube side flange, which is the radially outer side of the porcelain tube side flange, and the outer circumferential side portion of the container side flange, which is the radially outer side of the container side flange, are fastened and fixed by a flange fastening member capable of fastening the outer circumferential side portion of the porcelain tube side flange and the outer circumferential side portion of the container side flange.

6. An electric device provided with the bushing structure according to any one of claims 1 to 5, An electric device, characterized in that at least one of a vacuum interrupter and a disconnecting switch is electrically connected to the conductor in the porcelain tube while being housed in the container.

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