Contact system with vacuum interrupter chamber and vacuum switch

Abstract

This invention relates to a contact system with a vacuum interrupter and a vacuum switch, comprising a moving contact, a stationary contact, a bellows, a ceramic housing, and moving-end and stationary-end metal seals respectively fixed at both ends of the ceramic housing. It also includes an insulating housing, an inlet terminal, and an outlet terminal. The insulating housing is a barrel-shaped structure matching the shape of the ceramic housing and tightly encasing the ceramic housing therein. The first end of the opening of the insulating housing extends upward beyond the moving-end metal seal at the upper end of the ceramic housing. This invention, by designing the first end of the insulating housing to extend above the moving-end metal seal of the ceramic housing, significantly increases the creepage distance on the outer surface of the vacuum interrupter while having minimal impact on the wall thickness of the insulating housing sidewalls. This maintains a smaller radial width of the vacuum interrupter, improves the insulation level of the vacuum interrupter, prevents flashover under high lightning impulse voltages, reduces product size, and facilitates product miniaturization.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vacuum switches, in particular to improvements in the insulation housing structure of the arc-extinguishing chamber. BACKGROUND

[0002] The contact system of a vacuum switch comprises a moving contact, a static contact and a vacuum arc-extinguishing chamber covering the periphery of the moving and static contacts. Generally, the vacuum arc-extinguishing chamber comprises a ceramic housing and a moving end metal sealing body and a static end metal sealing body respectively arranged at the two ends of the ceramic housing. The moving end metal sealing body and the static end metal sealing body seal the two ends of the ceramic housing to form a vacuum environment inside the ceramic housing. Therefore, the insulation performance inside the ceramic housing is good, but the outer surface of the ceramic housing is in contact with air. Under a large lightning impulse voltage, flashover may occur along the outer surface of the ceramic housing. In order to solve this problem, the existing ceramic housing generally adopts an umbrella skirt structure to increase the creepage distance of the upper and lower conductive ends. However, the umbrella skirt structure inevitably occupies a large radial width, which is not conducive to reducing the volume of the product. Especially for small-sized vacuum arc-extinguishing chambers with dimensions of about 40mm*40mm*25mm to 65mm*65mm*40mm applied in high-voltage direct-current relays or miniature high-voltage disconnectors, the space inside the product is more limited, and it is difficult to have spare space to set up the umbrella skirt structure. Moreover, when the internal structure of the product is compact, the electric field distribution is also uneven. For example, when the inventors developed a small-sized vacuum arc-extinguishing chamber applied in a high-voltage direct-current relay or a miniature high-voltage disconnector, under the condition of a rated voltage of 12kV and a rated current of 40A, the vacuum arc-extinguishing chamber was required to withstand a lightning impulse of 25kV-30kV without flashover. However, in the actual design process, it was found that due to the compact internal structure of the product, the electric field distribution was uneven, and flashover was more likely to occur, resulting in failure of the test.

[0003] Therefore, there is an urgent need to design a structure that can improve the creepage distance of the outer surface of the vacuum arc-extinguishing chamber without excessively affecting the radial width dimension of the vacuum arc-extinguishing chamber. SUMMARY

[0004] In view of the above problems, the present application provides a contact system with a vacuum arc-extinguishing chamber with an optimized structure, which can improve the creepage distance of the outer surface of the vacuum arc-extinguishing chamber while maintaining a relatively small radial width.

[0005] The present application adopts the following technical solutions:

[0006] The application provides a contact system with a vacuum arc-extinguishing chamber, comprising a moving contact, a static contact, a bellows, a ceramic shell, and a moving end metal sealing body and a static end metal sealing body fixedly arranged at two ends of the ceramic shell respectively, wherein one end of the moving end metal sealing body and the bellows is fixed and both are sleeved on the moving contact and seal the upper end of the ceramic shell, the static end metal sealing body is electrically connected with the static contact and seals the lower end of the ceramic shell, and the contact system further comprises an insulating shell, an incoming line terminal and an outgoing line terminal,

[0007] The insulating shell is a barrel-shaped structure matching the shape of the ceramic shell and tightly embedding the ceramic shell therein, the insulating shell comprises an open first end, a closed second end and a side wall between the first end and the second end, and the opening of the first end of the insulating shell is higher than the moving end metal sealing body of the upper end of the ceramic shell,

[0008] The incoming line terminal is electrically connected with the moving contact, and the incoming line terminal is arranged at a position higher than the first end of the insulating shell, and the outgoing line terminal is electrically connected with the static end metal sealing body and leads out of the insulating shell.

[0009] In order to maximize the creepage distance of the outer surface of the arc-extinguishing chamber, in one embodiment, the outgoing line terminal is preferably led out of the lower end of the insulating shell.

[0010] In order to resist the electrodynamic repulsive force caused by the short-circuit current and reduce the space occupation, the contact system further comprises an electrodynamic repulsive force resisting structure, the incoming line terminal and the moving contact are electrically connected through the electrodynamic repulsive force resisting structure, the electrodynamic repulsive force resisting structure comprises a first Rogowski coil, a second Rogowski coil and a soft connection, the first Rogowski coil and the second Rogowski coil are arranged face to face one above the other, the first Rogowski coil is fixedly electrically connected with the incoming line terminal, the second Rogowski coil is fixedly electrically connected with the moving contact, the soft connection connects the first Rogowski coil and the second Rogowski coil in series, and when current passes through the first Rogowski coil and the second Rogowski coil, the current flow directions in the first Rogowski coil and the second Rogowski coil are opposite, so that the first Rogowski coil and the second Rogowski coil generate magnetic fields of the same polarity between them to repel the second Rogowski coil and the moving contact.

[0011] In order to utilize the internal space formed by the upward increase of the first end, so that the structure is compact and reasonable, in one embodiment, the outer diameter of the second Rogowski coil is smaller than the diameter of the opening of the first end of the insulating shell, and the second Rogowski coil is arranged at a position lower than the opening of the first end, so that the second Rogowski coil is arranged inside the insulating shell.

[0012] In one embodiment, preferably the insulating shell is cast on the outside of the ceramic shell in liquid form so that the ceramic shell is tightly fitted to the sidewall of the insulating shell.

[0013] In one embodiment, preferably the outer contour of the sidewall is substantially arc-shaped, including two rounded edges on one side and two straight edges on the other side, for easy demolding and improved processability.

[0014] In one embodiment, preferably the insulating shell is made of epoxy resin material to ensure good insulation and adhesion.

[0015] In one embodiment, preferably the insulating shell is cast in a vacuum environment to avoid air bubbles between the sidewall and the ceramic shell.

[0016] Based on the above-mentioned contact system with vacuum interrupter, the present application further provides a vacuum switch comprising the above-mentioned contact system.

[0017] In order to improve structural compactness and save installation space, the vacuum switch further comprises an electromagnetic operating mechanism for driving the movable contact, and a transmission lever for transmission connection between the movable contact and the electromagnetic operating mechanism, the electromagnetic operating mechanism and the contact system are arranged in parallel and in the same direction, the transmission lever is arranged on the same side of the electromagnetic operating mechanism and the contact system, and the transmission lever is transmission connected with the electromagnetic operating mechanism and the movable contact at both ends, so that the electromagnetic operating mechanism, the transmission lever and the contact system are arranged in a “[” shape.

[0018] The present application has the following advantages: by designing the first end of the insulating shell to be higher than the metal sealing body of the movable end of the ceramic shell, the creepage distance of the outer surface of the vacuum interrupter is greatly increased, the wall thickness of the sidewall of the insulating shell is less affected, the radial width of the vacuum interrupter can be kept small, the insulation level of the vacuum interrupter is improved, flashover does not occur under high lightning impulse voltage, the product size is reduced, and the product is miniaturized. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is an exploded view of the structure of the vacuum switch in the embodiment;

[0020] Figure 2 is a perspective view of the electromagnetic operating mechanism, the transmission lever and the contact system in the embodiment;

[0021] Figure 3 is a front view of the contact system in the embodiment;

[0022] Figure 4is an exploded view of the contact system of the embodiment (part 1, disassembling the insulating housing, but not disassembling the electric repulsion holding structure);

[0023] Figure 5 is an exploded view of the contact system of the embodiment (part 2, disassembling the insulating housing and the electric repulsion holding structure);

[0024] Figure 6 is a top view of the contact system of the embodiment;

[0025] Figure 7 is Figure 6 is a sectional view at A-A in the embodiment;

[0026] Figure 8 is Figure 6 is a sectional view at B-B in the embodiment;

[0027] Figure 9 is a schematic view of the insulating housing of the embodiment. DETAILED DESCRIPTION

[0028] To further illustrate the embodiments, the present application provides accompanying drawings. These drawings are part of the disclosure of the present application, which mainly serve to illustrate the embodiments, and can be used to explain the operating principles of the embodiments in conjunction with the relevant description. Those of ordinary skill in the art should be able to understand other possible implementations and advantages of the present application in conjunction with these. The components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0029] The present application is further illustrated in conjunction with the accompanying drawings and specific embodiments.

[0030] Referring to Figures 1-2 As a preferred embodiment of the present application, a vacuum switch is provided, which comprises a housing, a circuit board, an electromagnetic operating mechanism 10, a transmission lever 20 and a contact system 30, referring to Figure 5 and Figure 7 The contact system 30 further comprises a moving contact 8, a stationary contact 9, a bellows 100 and a ceramic housing 2. For ease of description, the end facing the moving contact 8 is defined as the upper end, and the end facing the stationary contact 9 is defined as the lower end. The ceramic housing 2 is fixedly provided with a moving end metal sealing body 4 and a stationary end metal sealing body 3 at the upper and lower ends, respectively. The moving end metal sealing body 4 has a ring structure, and the bellows 100 is fixedly sleeved on the moving contact 8 at one end and fixed with the moving end metal sealing body 4 at the other end. The stationary end metal sealing body 3 has a plate structure, and the moving end metal sealing body 4, the bellows 100 and the stationary end metal sealing body 3 respectively seal the two ends of the ceramic housing 2 to form an arc-extinguishing chamber in the interior of the ceramic housing 2. The moving end metal sealing body 4 is sleeved on the moving contact 8 to form an electrical connection with the moving contact 8, and the stationary end metal sealing body 3 is electrically connected with the stationary contact 9. The moving contact 8 can move in the up-down direction (i.e.Figure 7 The movable contact 8 moves in the direction T' - T (T' - T direction) to achieve contact or separation with the static contact 9, thereby achieving the on or off of the contact system 30.

[0031] The electromagnetic operating mechanism 10 is used to drive the movable contact 8 in an electric way, and has a driving end for achieving displacement driving. A conductive push rod is fixedly connected to the end of the movable contact 8 away from the static contact 9. The transmission lever 20 is arranged on the same side of the electromagnetic operating mechanism 10 and the contact system 30. The middle segment position of the transmission lever 20 is hingedly limited. The two ends of the transmission lever 20 are respectively hingedly connected with the driving end of the electromagnetic operating mechanism 10 and the conductive push rod, so as to achieve the transmission connection between the electromagnetic operating mechanism 10 and the movable contact 8. Wherein, the electromagnetic operating mechanism 10 and the contact system 30 are arranged in parallel and in the same direction along the up-down direction. The transmission lever 20 is transmissionally connected with the electromagnetic operating mechanism 10 and the movable contact 2, so that the electromagnetic operating mechanism 10, the transmission lever 20 and the contact system 30 are arranged in a "[ " type connection, which can make the structure of the vacuum switch compact and save the installation space. In the prior art, the electromagnetic operating mechanism and the contact system are usually arranged vertically. The electromagnetic operating mechanism and the contact system are connected by a connecting rod mechanism, which occupies a large space and is not conducive to the miniaturization of the product. Figures 1-2 As shown in the figure, the electromagnetic operating mechanism 10 and the contact system 30 are horizontally arranged, thereby reducing the space occupation of the vacuum switch in the height direction.

[0032] Referring to Figures 3-7 , the contact system 30 further comprises an insulating shell 1, which is in a barrel structure and comprises an open first end 13, a closed second end 11 and a side wall 12 between the first end 13 and the second end 11. The ceramic shell 2 is embedded in the insulating shell 1, and the ceramic shell 2 is tightly fitted to the side wall 12 of the insulating shell 1. The first end 13 of the insulating shell 1 is higher than the movable end metal sealing body 4. The contact system further comprises an incoming line terminal 6 and an outgoing line terminal 5. The outgoing line terminal 5 is electrically connected with the static end metal sealing body 3 and leads out of the insulating shell 1. The incoming line terminal 6 is electrically connected with the movable contact 8, and the incoming line terminal 6 is arranged at a position higher than the insulating shell 5. Thus, as shown in the figure, under the structure of the embodiment, the creepage distance L of the outer surface of the vacuum arc-extinguishing chamber is equal to 2D0+d+L0, wherein D0 represents the height of the first end 13 higher than the movable end metal sealing body 4, L0 represents the wall thickness of the side wall 12, and d is related to the position of the outgoing line terminal 5 in the axial direction of the side wall 11. In order to further improve the creepage distance, the outgoing line terminal 5 is preferably led out from the lower end of the insulating shell 5 in the embodiment, so as to maximize the value of d. Figure 7

[0033] ​The embodiment increases the creepage distance of the outer surface of the vacuum interrupter by the design that the first end 13 is higher than the dynamic end metal sealing body 4, and has little influence on the wall thickness of the side wall 12. Even if the wall thickness of the side wall 12 is thin, the height of the first end 13 higher than the dynamic end metal sealing body 4 is enough to ensure the creepage distance of the outer surface of the vacuum interrupter, improve the insulation level of the vacuum interrupter, and reduce the product volume, which is beneficial to the miniaturization of the product. In addition, the structure of the insulation shell 1 in the embodiment is simple and easy to form, and it is not necessary to design a complex umbrella skirt structure as in the prior art.

[0034] As Figures 4-5 and Figures 7-8 The power-in terminal 6 and the moving contact 8 are also provided with an electrodynamic repulsion resistance structure 7 for electrically connecting the power-in terminal 6 and the moving contact 8, which includes a first Rogowski coil 71, a second Rogowski coil 73 and a soft connection 72. The first Rogowski coil 71 and the second Rogowski coil 73 are arranged to face each other in the up-down direction. The first Rogowski coil 71 is fixedly electrically connected with the power-in terminal 6, and the second Rogowski coil 73 is fixedly electrically connected with the moving contact 8. The soft connection 72 connects the first Rogowski coil 71 and the second Rogowski coil 73 in series, so that when the current passes through the first Rogowski coil 71 and the second Rogowski coil 73, the current flow directions in the first Rogowski coil 71 and the second Rogowski coil 73 are opposite, and the first Rogowski coil 71 and the second Rogowski coil 73 generate magnetic fields with the same polarity between them. When a short circuit occurs in the circuit, a large current will generate an electrodynamic repulsion between the moving and static contacts, repelling the moving contact 8. However, for a vacuum switch, it is necessary to be able to bear the short-circuit current and ensure that the moving and static contacts are still in a closed state under short circuit. The embodiment provides the electrodynamic repulsion resistance structure 7, when the short-circuit current flows through the first Rogowski coil 71 and the second Rogowski coil 73, the first Rogowski coil 71 and the second Rogowski coil 73 generate magnetic fields with same polarity between them, and the second Rogowski coil 73 and the moving contact 8 are repelled in the direction of the static contact 9, resisting the electrodynamic repulsion between the moving and static contacts, so that the moving contact 8 and the static contact 9 remain in a closed state, meeting the demand of bearing short-circuit current.

[0035] In the structure of the embodiment, the electromagnetic operating mechanism 10, the transmission lever 20 and the contact system 30 are arranged in a "[ ]" type connection, the space between the contact system 30 and the transmission lever 20 is small, and the structure of the overall vacuum switch is very compact. In order to set the electric repulsion force maintaining structure under the premise of this compact structure, the electric repulsion force maintaining structure cannot occupy too much space in the up-down direction (T'-T direction). Therefore, the first and second Roebel coils 71 and 73 are used to form the same-pole repulsion magnetic field in the embodiment, so as to resist the electric repulsion force between the moving and static contacts. Compared with the conventional scheme of using a solenoid to realize the electric magnetic field, the axial space occupied by the Roebel coils is small, and the requirement of the structure arrangement of the vacuum switch in the embodiment can be met.

[0036] As shown in Figure 7 , the outer diameter of the second Roebel coil 73 is smaller than the caliber of the first end 13 of the opening of the insulating shell 1, and the second Roebel coil 73 is arranged at a position lower than the opening of the first end 13, so that the second Roebel coil 73 is arranged in the insulating shell 1. The internal space formed by the upward increase of the first end 13 is further utilized, so that the structure is compact and reasonable. At the same time, the movement stroke of the second Roebel coil 73 is protected from being interfered by external components.

[0037] The close fit of the ceramic shell 2 and the side wall 12 can be realized by a casting process, that is, a mold is prepared, the ceramic shell 2 and the vacuum arc-extinguishing chamber structure integrated with the ceramic shell 2 are put into the mold, and then the insulating shell 1 is formed outside the ceramic shell 2 by means of liquid casting. Thus, the ceramic shell 2 can be closely fitted to the side wall 12 of the insulating shell 1. The insulating shell 1 can be made of any material with good insulation, easy solidification and molding, and certain bonding properties, for example, the insulating shell 1 in the embodiment is made of epoxy resin by casting. The casting process is most preferably carried out in a vacuum environment to avoid air bubbles between the side wall 12 and the ceramic shell 2.

[0038] As shown in Figure 7 , the outer contour of the side wall 12 is generally arc-shaped, including two rounded edges 121 and 122 on one side and two straight edges 123 and 124 on the other side. Through the design of the inclined rounded edges, the electric field can be more uniform without sharp ends. The straight edges 123 and 124 can cooperate with the vacuum switch shell to form a glue injection groove, facilitating sealing.

[0039] Although the application is specifically shown and introduced in combination with the preferred embodiments, those skilled in the art should understand that various changes can be made to the application in form and details without departing from the spirit and scope of the application as defined in the appended claims.

Claims

1. A contact system with vacuum interrupter, comprising a moving contact, a stationary contact, a bellows, a ceramic housing and a moving end metal sealing body and a stationary end metal sealing body fixedly arranged at both ends of the ceramic housing respectively, defining an upper end towards the moving contact and a lower end towards the stationary contact, wherein the moving end metal sealing body and the bellows are fixed and both are sleeved on the moving contact and seal the upper end of the ceramic housing, the stationary end metal sealing body is electrically connected with the stationary contact and seals the lower end of the ceramic housing, characterized in that: Further comprising an insulating shell, an incoming terminal and an outgoing terminal, The insulating shell is a barrel structure matching the shape of the ceramic shell, and tightly embeds the ceramic shell therein, the insulating shell comprises an open first end, a closed second end and a sidewall between the first end and the second end, the opening of the first end of the insulating shell is higher than the moving end metal seal body of the upper end of the ceramic shell, The incoming terminal is electrically connected with the moving contact, and the incoming terminal is arranged at a position higher than the first end of the insulating shell, and the outgoing terminal is electrically connected with the static end metal seal body and leads out of the insulating shell, The height of the first end of the double insulating shell higher than the moving end metal seal body is doubled to improve the creepage distance of the outer surface of the vacuum interrupter.

2. The contact system with vacuum interrupter according to claim 1, characterized in that: The outgoing terminal leads out of the lower end of the insulating shell.

3. The contact system with vacuum interrupter according to claim 1, characterized in that: Further comprising an electric repulsion resistance structure, the incoming terminal and the moving contact are electrically connected through the electric repulsion resistance structure, the electric repulsion resistance structure comprises a first solenoid, a second solenoid and a soft connection, the first solenoid and the second solenoid are arranged face to face one above the other, the first solenoid is fixedly electrically connected with the incoming terminal, the second solenoid is fixedly electrically connected with the moving contact, the soft connection connects the first solenoid and the second solenoid in series, and when current passes through the first solenoid and the second solenoid, the current flow directions in the first solenoid and the second solenoid are opposite, so that the first solenoid and the second solenoid respectively generate magnetic fields of the same polarity between them to repel the second solenoid and the moving contact.

4. The contact system with vacuum interrupter according to claim 3, characterized in that: The outer diameter of the second solenoid is smaller than the diameter of the opening of the first end of the insulating shell, and the second solenoid is arranged at a position lower than the opening of the first end, so that the second solenoid is arranged inside the insulating shell.

5. The contact system with vacuum interrupter according to claim 1, characterized in that: The insulating shell is formed by liquid casting on the outside of the ceramic shell, so that the ceramic shell is tightly fitted to the sidewall of the insulating shell.

6. The contact system with vacuum interrupter according to claim 5, characterized in that: The outer contour of the sidewall is arc-shaped, comprising two rounded edges on one side and two straight edges on the other side.

7. The contact system with vacuum interrupter according to claim 5, characterized in that: The insulating shell is formed by casting of epoxy resin material.

8. The contact system with vacuum interrupter according to claim 5, characterized in that: The liquid casting of the insulating shell is performed in a vacuum environment.

9. Vacuum switch comprising a contact system for its making or breaking, characterized in that: The contact system is the contact system with a vacuum interrupter as claimed in any one of claims 1-8.

10. The vacuum switch of claim 9, wherein: Further comprising an electromagnetic operating mechanism for driving the moving contact, and a transmission lever for transmission connection between the moving contact and the electromagnetic operating mechanism, the electromagnetic operating mechanism and the contact system are arranged in parallel and in the same direction, the transmission lever is arranged on the same side of the electromagnetic operating mechanism and the contact system, and the transmission lever is transmission connected with the electromagnetic operating mechanism and the moving contact at both ends respectively, so that the electromagnetic operating mechanism, the transmission lever and the contact system are arranged in a "[” type connection.

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