Vacuum circuit breaker

Abstract

A vacuum circuit breaker (1) is provided with: a vacuum container (2) and a fixed electrode (3) and a movable electrode (4) provided in the vacuum container (2). The vacuum container (2) is constituted by airtightly connecting a fixed side end plate (6) and a movable side end plate (7) to one end portion of an insulating tube (5) and the other end portion of the insulating tube (5), respectively. The insulating tube (5) is provided with a protruding portion (5a) protruding along the outer periphery of the insulating tube (5) in the axial direction of the insulating tube (5) at its end portion. The insulating tube (5) is provided with an end plate connecting portion (5b) protruding from the base end portion of the protruding portion (5a) toward the inner periphery of the insulating tube (5) at its end portion. The end plate connecting portion (5b) is provided with a metallized layer (8) on its surface, and the fixed side end plate (6) (or the movable side end plate (7)) is connected to the metallized layer by brazing. The metallized layers (8) are each provided with: a coupling portion (8a) extending in the radial direction of the insulating tube (5); and an extending portion (8b) extending from an end portion of the coupling portion (8a) on the inner circumference side of the insulating tube (5) in the axial direction of the insulating tube (5).

Description

Technical Field

[0001] The present invention relates to a vacuum circuit breaker, and in particular to a structure of an insulating tube constituting a vacuum circuit breaker or a structure of an internal structural component of a vacuum circuit breaker. Background Art

[0002] The vacuum circuit breaker is configured to have a fixed electrode and a movable electrode in a vacuum container (eg, Patent Documents 1 and 2).

[0003] The vacuum container is equipped with an insulating tube formed of a ceramic material or the like, and a fixed side end plate and a movable side end plate provided at the end portion of the insulating tube. The insulating tube is formed with a metallization layer on its end surface. The fixed side end plate or the movable side end plate is bonded to the metallization layer by brazing.

[0004] The thickness of the metallization layer is extremely thin. Therefore, when a high voltage is applied to the vacuum circuit breaker, the electric field will be higher than other parts, causing the risk of surface flashover starting from this part outside the insulating tube. In other words, there is a risk that the withstand voltage performance will be reduced at the joint part between the insulating tube and the fixed side end plate (or the movable side end plate).

[0005] Therefore, in Patent Document 1 Figure 4 In the invention, the insulating tube is provided with a protruding portion protruding in the axial direction of the insulating tube at its end portion, and a U-shaped groove portion is formed at a base end portion of the protruding portion on the end surface of the insulating tube. By providing such a protruding portion, the end portion of the metallized layer on the outer peripheral side of the insulating tube is not exposed to the environment of the vacuum circuit breaker, and the electric field of the end portion of the metallized layer on the outer peripheral side of the insulating tube is reduced (relaxed). By forming the U-shaped groove at the base end portion of the protruding portion on the end surface of the insulating tube, the electric field of the end portion of the metallized layer on the outer peripheral side of the insulating tube is reduced.

[0006] However, when the groove is formed on the end surface of the insulating tube, the processing for manufacturing the insulating tube may become complicated, and the metal mold for manufacturing the insulating tube may become complicated. In addition, the formation of the groove may reduce the strength of the insulating tube.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent document 1: Japanese Patent Application Publication No. 2010-282923.

[0010] Patent document 2: Japanese Patent Application Publication No. 2017-147026. Summary of the invention

[0011] The present invention has been achieved in view of the above circumstances, and an object of the present invention is to provide a technology for improving the withstand voltage performance of a vacuum circuit breaker.

[0012] One aspect of the vacuum circuit breaker of the present invention for achieving the object includes:

[0013] a vacuum container in which both end portions of a cylindrical insulating tube are hermetically sealed by end plates;

[0014] A pair of electrodes provided in the vacuum container such that the pair of electrodes can be separated from and contacted with each other;

[0015] A protruding portion protrudes from the end portion of the insulation tube in an axial direction of the insulation tube, the protruding portion being formed along an outer circumference of the insulation tube.

[0016] an end plate coupling portion provided to protrude from a base end portion of the protruding portion in an inner circumferential direction of the insulating tube; and

[0017] A metallization layer is provided at a surface of the end plate coupling portion, the end plate being coupled to the metallization layer.

[0018] In addition, according to another aspect of the vacuum circuit breaker of the present invention for achieving the purpose, in the above-mentioned vacuum circuit breaker, the metallization layer includes: a connecting portion extending in the radial direction of the insulating tube, and the end plate is connected to the connecting portion; and an extending portion extending from the end portion of the connecting portion on the inner peripheral side of the insulating tube along the axial direction of the insulating tube.

[0019] Furthermore, according to another aspect of the vacuum circuit breaker of the present invention for achieving the object, in the above-mentioned vacuum circuit breaker, the electric field reduction shield is provided on an electrode shaft supporting the electrode in the insulating tube, or provided on the inner side of the insulating tube of the end plate,

[0020] The electric field reduction shield is opposite to at least an end portion of the metallization layer in a radial direction of the insulating tube.

[0021] Moreover, according to another aspect of the vacuum circuit breaker of the present invention for achieving the object, in the above-mentioned vacuum circuit breaker, a connecting portion for smoothly connecting the inner peripheral surface of the protruding portion with a connecting surface of an end plate connecting portion is provided between the inner peripheral surface of the protruding portion and the connecting surface of the end plate connecting portion to which the end plate is connected, and

[0022] The metallization layer is provided to extend along the connection portion from a coupling surface of the end plate coupling portion toward an inner peripheral surface of the protruding portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a cross-sectional view of main components of a vacuum circuit breaker according to an embodiment of the present invention;

[0024] Figure 2 is an enlarged cross-sectional view of a fixed-side end plate coupling portion of a vacuum circuit breaker according to an embodiment of the present invention;

[0025] Figure 3 (a) is a view showing an electric field analysis portion of a vacuum circuit breaker according to an embodiment of the present invention; Figure 3 (b) is a view showing an electric field analysis portion of a vacuum circuit breaker according to another embodiment of the present invention; and

[0026] Figure 4 is an enlarged sectional view of a fixed-side end plate coupling portion of a vacuum circuit breaker according to another embodiment of the present invention. DETAILED DESCRIPTION

[0027] Hereinafter, a vacuum circuit breaker according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Figures 1 to 4 The drawings shown in FIG. 1 are views schematically showing a vacuum circuit breaker according to an embodiment of the present invention. The sizes shown in the drawings do not necessarily correspond to actual sizes.

[0028] like Figure 1 As shown in FIG. 1 , a vacuum circuit breaker 1 according to an embodiment of the present invention is equipped with a vacuum container 2 , and a fixed electrode 3 and a movable electrode 4 provided in the vacuum container 2 .

[0029] The vacuum container 2 is equipped with: a cylindrical insulating tube 5 formed of a ceramic material or the like; and a fixed side end plate 6 and a movable side end plate 7 provided at end portions of the insulating tube 5, respectively. The fixed side end plate 6 is airtightly coupled to one end portion of the insulating tube 5, and the movable side end plate 7 is airtightly coupled to the other end portion of the insulating tube 5. Thus, the interior of the vacuum container 2 is sealed by the fixed side end plate 6 and the movable side end plate 7 so as to form a vacuum.

[0030] The end portion of the insulating tube 5 is equipped with a protruding portion 5a along the outer circumference of the insulating tube 5 so as to protrude in the axial direction of the insulating tube 5. The end plate coupling portion 5b is provided on the inner circumferential side of the base end portion of the protruding portion 5a. The fixed side end plate 6 (or the movable side end plate 7) is coupled to the end plate coupling portion 5b. The radial thickness of the insulating tube 5 is formed so as to become thicker at the protruding portion of the end plate coupling portion 5b, for example, and then gradually become the same thickness as the central portion of the insulating tube 5 from the end of the end plate coupling portion 5b located on the inner side of the insulating tube 5. It is sufficient to make the end plate coupling portion 5b protrude from the inner wall of the insulating tube 5 toward the radial inner side of the insulating tube 5. Therefore, for example, there can also be a mode in which the end plate coupling portion 5b protrudes so that not only the surface of the end plate coupling portion 5b on the end side of the insulating tube 5 is parallel to the radial direction of the insulating tube 5, but also the surface on the inner side of the insulating tube 5 is parallel to the radial direction of the insulating tube 5. Both the protruding portion 5a and the end plate coupling portion 5b are formed integrally with the insulating tube 5. The end plate coupling portion 5b is provided with a metallized layer 8 to which the fixed side end plate 6 (or the movable side end plate 7) is coupled by brazing or the like. As a brazing material for coupling the fixed side end plate 6 (or the movable side end plate 7) by brazing, a silver-based composite material is mainly used.

[0031] like Figure 2 As shown in FIG. 1 , the end plate coupling portion 5b is provided to protrude from the base end portion of the protruding portion 5a toward the inner side in the radial direction of the insulating tube 5. The end plate coupling portion 5b is provided with: a coupling surface 5c to which the fixed side end plate 6 is coupled; and an inner peripheral surface 5d extending from the protruding end of the coupling surface 5c in the axial direction of the insulating tube 5. The coupling surface 5c of the end plate coupling portion 5b is a surface extending from the base end portion of the protruding portion 5a toward the inner side in the radial direction of the insulating tube 5, and is formed along the inner periphery of the insulating tube 5. The inner peripheral surface 5d of the end plate coupling portion 5b is an end surface protruding toward the inner side in the radial direction of the insulating tube 5 of the end plate coupling portion 5b, and is a surface forming a part of the inner peripheral surface of the insulating tube 5. The protruding portion 5a and / or the end plate coupling portion 5b and the metallized layer 8 at the end portion of the insulating tube 5 provided with the movable side end plate 7 have the same shape as the protruding portion 5a and / or the end plate coupling portion 5b and the metallized layer 8 at the end portion of the insulating tube 5 provided with the fixed side end plate 6. Therefore, similar structures are denoted by the same symbols, and their detailed description is omitted.

[0032] The metallized layer 8 is provided with a coupling portion 8a provided on a coupling surface 5c of the end plate coupling portion 5b and an extension portion 8b provided on an inner peripheral surface 5d of the end plate coupling portion 5b. That is, the metallized layer 8 is provided with the coupling portion 8a extending in the radial direction of the insulating tube 5 and the extension portion 8b extending from an end portion of the coupling portion 8a on the inner peripheral side of the insulating tube 5 in the axial direction of the insulating tube 5. The coupling portion 8a and the extension portion 8b are formed as a single piece / integral body.

[0033] like Figure 1 As shown in FIG. 1 , the fixed electrode 3 and the movable electrode 4 are arranged in the vacuum container 2 so that they are opposite to each other. The fixed electrode rod 3 a is coupled to the fixed electrode 3 by brazing. Moreover, the movable electrode rod 4 a is coupled to the movable electrode 4 by brazing. Moreover, an intermediate shield 9 is provided inside the vacuum container 2 so as to cover the fixed electrode 3 and the movable electrode 4, thereby preventing the inner surface of the vacuum container 2 from being contaminated by metal vapor generated by the arc between the fixed electrode 3 and the movable electrode 4.

[0034] The fixed electrode rod 3a is an electrode shaft supporting the fixed electrode 3 in the insulating tube 5, and is provided to pass through the fixed-side end plate 6. The fixed electrode rod 3a is provided with an electric field reduction shield 10. The electric field reduction shield 10 is provided to oppose the metallization layer 8 (i.e., the extended portion 8b of the metallization layer 8) formed on the protruding end surface of the end plate coupling portion 5b.

[0035] The movable electrode rod 4a is an electrode shaft that supports the movable electrode 4 in the insulating tube 5, and is provided to pass through the movable side end plate 7. The movable electrode rod 4a moves in the axial direction by an external operating mechanism not shown in the figure. By moving the movable electrode rod 4a in the axial direction, the fixed electrode 3 and the movable electrode 4 are contacted or separated, thereby performing a switching action (power supply and shutdown) of the vacuum circuit breaker 1. The bellows 11 is provided between the movable side end plate 7 and the movable electrode rod 4a so as to cover the outer periphery of the movable electrode rod 4a.

[0036] The bellows 11 is made of thin stainless steel in a serpentine shape, and enables the movable electrode rod 4a to move in the axial direction while maintaining the vacuum seal inside the vacuum container 2. Although not shown in the drawings, the bellows 11 is provided with a bellows shield at an end portion on the side of the movable electrode 4. The bellows shield prevents the bellows 11 from being contaminated by metal vapor generated by the arc between the fixed electrode 3 and the movable electrode 4.

[0037] The fixed side end plate 6 is formed in a deep pan shape, and the flange end portion of the deep pan shape is joined to the metallized layer 8 provided at the end plate joining portion 5b (specifically, the joining portion 8a of the metallized layer 8) by brazing. The fixed side end plate 6 is formed with a hole through which the fixed electrode rod 3a passes.

[0038] The movable side end plate 7 is formed in a deep pan shape, and the flange end portion of the deep pan shape is connected to the metallization layer 8 (specifically, the connecting portion 8a of the metallization layer 8) provided at the end plate connecting portion 5b by brazing. The movable side end plate 7 is formed with a hole through which the movable electrode rod 4a passes. Moreover, the movable side end plate 7 is provided with an electric field reduction shield 12. The electric field reduction shield 12 extends in the vacuum container 2 so as to be opposed to the metallization layer 8 (that is, the extended portion 8b of the metallization layer) formed on the protruding end surface of the end plate connecting portion 5b, and the end portion of the electric field reduction shield 12 is bent toward the inside of the vacuum container 2.

[0039] The electric field analysis of the vacuum circuit breaker 1 according to the embodiment of the present invention is performed below. The electric field analysis is performed using the electric field analysis software ElecNet (manufactured by Infolytica Co.). The electric field analysis is performed by assuming that a virtual ground surface is located at a position away from the insulating tube 5 of the vacuum circuit breaker 1, and the virtual ground surface is parallel to the central axis of the vacuum circuit breaker 1 (the axis of the fixed electrode rod 3a and the movable electrode rod 4a).

[0040] like Figure 3 As shown in (a), when the electric field analysis is performed on the end portion of the metallized layer 8 on the outer peripheral side of the insulating tube 5 (the portion surrounded by a circle in the figure), the electric field value is 7.56% / mm. The electric field value (% / mm) represents the ratio of the potential difference change per 1 mm, assuming that the voltage (V) applied between the electrodes of the vacuum circuit breaker 1 is 100%.

[0041] Furthermore, as another embodiment of the vacuum circuit breaker 1 of the present invention, Figure 3 An electric field analysis similar to that of the vacuum circuit breaker 1 is performed on the metallization layer 14 of the vacuum circuit breaker 13 shown in (b). When the electric field analysis is performed on the end portion of the metallization layer 14 on the outer peripheral side of the insulating tube 5 (the portion surrounded by a circle in the figure), the electric field value is 8.28% / mm. The vacuum circuit breaker 13 is similar in structure to the vacuum circuit breaker 1, except that the metallization layer 14 is not equipped with an extension portion extending in the axial direction of the insulating tube 5 (corresponding to the extension portion 8b of the vacuum circuit breaker 1). Therefore, structures similar to those of the vacuum circuit breaker 1 are represented by the same symbols, and their detailed description is omitted.

[0042] It can be understood from these two analysis results that by providing the end plate connecting portion 5b to protrude inwardly in the radial direction of the insulating tube 5 and by forming the metallization layer 8 having the extending portion 8b on the end plate connecting portion 5b, the electric field value of the vacuum circuit breaker 1 is approximately 10% lower than that of the vacuum circuit breaker 13.

[0043] By forming the end plate coupling portion 5 b to protrude from the inner peripheral surface of the insulating tube 5 in the radial direction of the insulating tube 5 , the vacuum interrupter 13 can improve the withstand voltage performance of the vacuum interrupter 13 without changing the diameter of the vacuum interrupter 13 .

[0044] According to the above-mentioned vacuum circuit breakers 1, 13 of the embodiment of the present invention, the end plate coupling portion 5b (the fixed side end plate 6 (or the movable side end plate 7) is coupled to the end plate coupling portion 5b) is provided to protrude inwardly in the radial direction of the insulating tube 5, and the fixed side end plate 6 (or the movable side end plate 7) having a diameter smaller than the outer diameter of the vacuum container 2 is provided on the end plate coupling portion 5b. In this way, the pressure resistance performance of the vacuum circuit breakers 1, 13 can be improved without changing the inner diameter and the outer shape of the vacuum container 2.

[0045] By providing the protruding portion 5a on the end portion of the insulating tube 5 so as to protrude in the axial direction of the insulating tube 5, the end portion of the metallized layer 8 on the outer peripheral side of the insulating tube 5 can be hidden from the outer peripheral portion of the vacuum container 2, thereby making it difficult for external flashover to occur through the shielding effect and improving the withstand voltage performance of the vacuum circuit breakers 1, 13.

[0046] In the case where the protruding portion 5a is provided at the end portion of the insulating tube 5, it is necessary to expand the outer shape of the insulating tube 5 by the thickness of the protruding portion 5a. In the case where the thickness of the protruding portion 5a is thin, the protruding portion 5a is easily broken. Therefore, in the vacuum circuit breaker 1, 13 according to the embodiment of the present invention, the end plate connecting portion 5b is provided to protrude inwardly in the radial direction of the insulating tube 5. Thereby, the pressure resistance performance of the vacuum circuit breaker 1 can be improved without changing the inner diameter and the outer shape of the vacuum container 2. That is, the thickness at the end plate connecting portion 5b of the insulating tube 5 is made thicker than the thickness of other parts of the insulating tube 5. In this way, the pressure resistance performance of the vacuum circuit breaker 1, 13 can be improved without changing the inner diameter and the outer shape of the vacuum container 2. Moreover, regardless of the inner diameter and the outer shape, the thickness of the protruding portion 5a can be selected. Therefore, the strength of the protruding portion 5a can be improved without changing the inner diameter and the outer shape of the vacuum container 2.

[0047] Furthermore, by extending the range of the metallization layer 8 , the electric field at the end portion of the metallization layer 8 on the outer peripheral side of the insulating tube 5 can be reduced, and the withstand voltage performance of the vacuum circuit breaker 1 can be improved.

[0048] By extending the metallized layer 8 to a range opposite to the electric field reduction shield 10 (or the electric field reduction shield 12), the electric field value of the end portion of the metallized layer 8 on the outer peripheral side of the insulating tube 5 can be reduced. However, the electric field value of the end portion of the metallized layer 8 on the inner peripheral side of the insulating tube 5 increases. Therefore, the electric field reduction shield 10 (or the electric field reduction shield 12) is provided to be opposite to the extended portion 8b of the metallized layer 8. Thereby, the electric field at the end portion of the metallized layer 8 on the inner peripheral side of the insulating tube 5 can be reduced. By providing the electric field reduction shield 10 (or the electric field reduction shield 12) to at least cover the end portion of the extended portion 8b extending from the coupling portion 8a in the axial direction of the insulating tube 5 (so as to be opposite to the end portion of the extended portion 8b in the radial direction of the insulating tube 5), the reduction in the withstand voltage performance at the end portion of the extended portion 8b (at which the electric field is concentrated) can be suppressed.

[0049] That is, the formation range of the metallization layer 8 is extended so as to form an extension portion 8b extending in the axial direction of the insulating tube 5, and the electric field reduction shield 10 (or the electric reduction shield 12) is provided to be opposite to the extension portion 8b of the metallization layer 8. Thus, the electric field at the end portion of the metallization layer 8 on the inner peripheral side of the vacuum container 2 can be reduced. Moreover, the protruding portion 5a is formed on the insulating tube 5, and the formation range of the metallization layer 8 is extended (that is, the metallization layer 8 is provided with the extension portion 8b). Thus, the electric field at the end portion of the metallization layer 8 on the outer peripheral side of the vacuum container 2 can be reduced.

[0050] As described above, the vacuum circuit breaker of the present invention is introduced by the specific embodiments shown. However, the vacuum circuit breaker of the present invention is not limited to these embodiments. The design can be appropriately modified without damaging its characteristics. The modified design also belongs to the technical scope of the present invention.

[0051] A vacuum circuit breaker partially having the features of the vacuum circuit breaker 1 described in the embodiment also belongs to the technical scope of the present invention. For example, a vacuum circuit breaker having the shape of the protruding portion 5a of the insulating tube 5 or the end plate coupling portion 5b or the shape of the metallized layer 8 can obtain the effects produced by the corresponding structures.

[0052] Moreover, if Figure 4As shown in , it is also possible to provide a mode in which a connection portion 5e for smoothly connecting the inner peripheral surface of the protruding portion 5a and the connection surface 5c of the end plate connection portion 5b is provided between the inner peripheral surface of the protruding portion 5a and the connection surface 5c of the end plate connection portion 5b, and a metallized layer 8 is provided along the curved surface of the connection portion 5e so as to extend from the connection surface 5c toward the direction of the inner peripheral surface of the protruding portion 5a. In this way, since the metallized layer 8 is applied along the curved surface of the connection portion 5e, it is possible to prevent the local enhancement of the electric field of the metallized layer 8 at the end portion of the outer peripheral side of the insulating container 2, thereby further improving the withstand voltage performance of the vacuum circuit breaker 15.

[0053] Moreover, regarding the shapes of the protruding portion 5a and the end plate connecting portion 5b, it is possible to provide not only a mode in which they are formed on both ends of the insulating tube 5, but also a mode in which they are formed on one end portion of the insulating tube 5, and a fixed side end plate 6 or a movable side end plate 7 is provided on the one end portion.

[0054] Furthermore, the shape of the fixed-side end plate 6 or the movable-side end plate 7 is not limited to the pan shape as long as it can airtightly seal one end of the insulating tube 5. For example, it may be a plate shape.

[0055] Furthermore, it is also possible to provide the electric field reduction shield 10 inside the insulating tube 5 of the fixed-side end plate 6 .

Claims

1. A vacuum circuit breaker, comprising: a vacuum container in which both end portions of a cylindrical insulating tube are hermetically sealed by end plates; A pair of electrodes, the pair of electrodes being provided in the vacuum container so that the pair of electrodes can be separated from each other and contacted with each other; a protruding portion protruding from the end portion of the insulation tube in an axial direction of the insulation tube, the protruding portion being formed along an outer circumference of the insulation tube; an end plate coupling portion provided to protrude inwardly from a base end portion of the protruding portion in a radial direction of the insulating tube so that a radial thickness at the end plate coupling portion of the insulating tube is thicker than a radial thickness of other portions of the insulating tube; as well as A metallization layer is provided at a surface of the end plate coupling portion, the end plate being coupled to the metallization layer.

2. The vacuum circuit breaker according to claim 1, wherein: The metallization layer includes: a coupling portion extending in a radial direction of the insulating tube, the end plate being coupled to the coupling portion; and an extending portion extending from an end portion of the coupling portion on an inner peripheral side of the insulating tube in an axial direction of the insulating tube.

3. The vacuum circuit breaker according to claim 1 or claim 2, wherein: an electric field reducing shield is provided on an electrode shaft supporting the electrode in the insulating tube, or on the inner side of the insulating tube of the end plate, The electric field reducing shield is opposite to at least an end portion of the metallization layer along a radial direction of the insulating tube.

4. The vacuum circuit breaker according to claim 1 or claim 2, wherein: A connecting portion that smoothly connects the inner peripheral surface of the protruding portion and the connecting surface of the end plate connecting portion is provided between the inner peripheral surface of the protruding portion and the connecting surface of the end plate connecting portion, to which the end plate is connected, and wherein: the metallization layer is provided to extend along the connection portion from a coupling surface of the end plate coupling portion toward an inner peripheral surface of the protruding portion.

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