Vacuum circuit breaker core unit for gas insulation

Abstract

The invention discloses a vacuum circuit breaker core unit for gas insulation, and particularly relates to the technical field of circuit breakers, the vacuum circuit breaker core unit comprises an equipment main body, a first main shaft and a vacuum arc-extinguishing chamber, and further comprises a multi-connecting-rod transmission mechanism which is driven by the first main shaft and converts rotary motion into linear motion through at least three stages of hinged connecting rods; a traditional cam mechanism is replaced to realize switching-on and switching-off operation of the vacuum arc-extinguishing chamber; and the voltage-sharing structure comprises a voltage-sharing cover covering the moving knife assembly and the static contact, and slotted holes formed between fixing points of the metal parts, and is used for enhancing the uniformity of the electric field and increasing the creepage distance. Through the integral structural design, the insulating property of the vacuum circuit breaker is improved, so that the requirement of an application scene with a higher voltage grade is met.

Description

Technical Field

[0001] The present invention relates to the technical field of lifting equipment circuit breakers, and more particularly to a core unit of a vacuum circuit breaker for gas insulation. Background Art

[0002] The vacuum circuit breaker is named because its arc extinguishing medium and the insulating medium of the contact gap after arc extinguishing are both high vacuum; it has the advantages of small size, light weight, suitable for frequent operation, and arc extinguishing without maintenance, and is widely used in distribution networks. The vacuum circuit breaker is a distribution device in a three-phase AC system. It can be used for the protection and control of electrical equipment in industrial and mining enterprises, power plants, and substations. It is particularly suitable for use in places that require oil-free, less maintenance, and frequent operation. The circuit breaker can be configured in a central cabinet, double-layer cabinet, or fixed cabinet to control and protect high-voltage electrical equipment.

[0003] For example, the Chinese patent with application number 201911104302.2 discloses a gas-insulated switchgear, including a fixed seat and a switch room, a mechanism room and a secondary wiring room arranged above the fixed seat, wherein a switch module is arranged in the switch room, and the switch module includes an integrated frame, and the frame is sequentially installed with a circuit breaker switch and an isolating grounding switch from top to bottom. By integrating the circuit breaker switch and the isolating grounding switch on the integrated frame, when assembling the switch module into the equipment box, there is no need to assemble each part one by one, which reduces the volume, facilitates stocking in the factory and simplifies the assembly process.

[0004] Although this patent reduces the size of the switch to a certain extent and can realize the opening and closing functions in the circuit through mechanical drive, the insulation performance of the vacuum circuit breaker is poor and cannot meet the application scenario requirements of higher voltage levels.

[0005] To this end, the present invention proposes a core unit for a gas-insulated vacuum circuit breaker to solve the above problems. Summary of the invention

[0006] In order to overcome the above defects of the prior art, an embodiment of the present invention provides a core unit of a vacuum circuit breaker for gas insulation, which solves the problems raised in the above background technology by providing a vacuum switch part and an isolating switch part.

[0007] To achieve the above object, the present invention provides the following technical solution: a core unit for a gas-insulated vacuum circuit breaker, comprising a device body, a first main shaft and a vacuum interrupter, and further comprising: The multi-link transmission mechanism is driven by the first main shaft and converts the rotary motion into linear motion through at least three levels of articulated links, replacing the traditional cam mechanism to realize the opening and closing operations of the vacuum interrupter; The voltage grading structure includes a voltage grading cover covering the moving blade assembly and the static contact, and slots opened between the fixing points of the metal parts, which are used to enhance the uniformity of the electric field and the creepage distance.

[0008] Preferably, the multi-link transmission mechanism includes a first link fixedly connected to the first main shaft, a second link hinged to the end of the first link, and a third link connecting the second link and the vacuum arc chamber, and the middle portion of the third link is slidably matched with the short shaft of the sleeve through a sliding groove.

[0009] Preferably, an outer cylinder with reinforcing ribs is embedded in the sliding groove of the third connecting rod, and the outer cylinder and the short axis of the sleeve form a surface contact structure for enhancing the connection strength between the outer cylinder and the sleeve.

[0010] Preferably, the surface of the voltage equalizing cover is provided with a corrugated electric field equalizing layer, and the thickness of the voltage equalizing cover decreases along the direction of the electric field strength gradient. The corrugated electric field equalizing layer is a periodic wave-shaped design on the surface of the voltage equalizing cover, usually made of metal or composite materials, and its corrugated shape disperses the electric field concentration area through regular changes in geometric shape, thereby reducing the local field strength peak.

[0011] Preferably, the slot edge adopts a rounded transition.

[0012] Preferably, the movable knife assembly comprises a swing rod hinged on the second main shaft, the end of the swing rod drives three movable knife blades through a connecting rod, and the contact surface between the movable knife blade and the grounding contact is provided with a silver coating.

[0013] Preferably, the cross section of the first main shaft is hexagonal to reduce wear.

[0014] Preferably, a grounding horizontal bar is integrated at the bottom of the device body, and the grounding horizontal bar is connected to an external grounding terminal through an L-shaped grounding vertical bar.

[0015] Preferably, a lifting plate is provided on the top of the equipment body.

[0016] Technical effects and advantages of the present invention: 1. The vacuum switch part in the present invention is provided with two side panels, and the various components in the vacuum switch part are fixed by a splint structure, which helps to reduce the volume of the entire switch. The provided vacuum arc extinguishing chamber can extinguish arcs in a vacuum, reduce contact erosion and fire risks, and extend the life of the equipment. The elastic part maintains the contact pressure to ensure that the upper and lower contacts of the vacuum arc extinguishing chamber are in close contact, reduce contact resistance, and reduce the risk of heating. The top outlet and bottom inlet design reduces the complexity of external cable wiring, and the highly conductive material reduces resistance loss and improves current carrying capacity. The insulator is slidably connected to the sleeve to ensure the flexibility of the vacuum arc extinguishing chamber while maintaining stable contact pressure. The overall structural design helps to improve the insulation performance of the vacuum circuit breaker, thereby meeting the requirements of application scenarios with higher voltage levels.

[0017] 2. In the present invention, insulating gas is sealed and stored in the box, which effectively isolates the internal arc and improves the overall insulation performance. An explosion-proof pressure relief device is provided, which automatically releases gas when the internal pressure exceeds the standard to prevent the box from exploding and ensure the safety of the equipment. The barometer monitoring can display the gas pressure in real time, which is convenient for timely inflation or maintenance to avoid insulation failure.

[0018] 3. The present invention is provided with a multi-link mechanism, which can convert the rotational motion from the first main shaft into linear motion, so as to drive the breaking and closing action of the moving end contact of the vacuum interrupter in the linear direction. Compared with the cam structure with the same stroke, it is smaller in size, lighter in weight and has a larger adjustable range of the driven parts. The second main shaft is installed with a shock absorbing material, which collides with the moving blade pull plate when the moving blade closes to absorb part of the kinetic energy, thereby preventing the moving blade from over-positioning when closing.

[0019] 4. The third connecting rod in the present invention drives the composite swing of the slide cylinder, the outer cylinder and the short shaft, and couples the linear motion trajectory of the short shaft with the arc trajectory of the third connecting rod through the sliding pair, so that the stress point of the short shaft is dynamically distributed along the slide groove, avoiding concentrated stress at a single point, significantly reducing the stress intensity per unit area, and reducing the risk of short shaft breakage. Multiple reinforcing ribs are set between the sleeve and the slide cylinder to form a triangular support structure, enhance the rigidity of the sleeve-slide cylinder assembly, suppress vibration and deformation, and indirectly protect the third connecting rod. The sleeve, slide cylinder and other components adopt a split structure design, which is convenient for replacing wear parts separately and prolonging the service life of the overall equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0021] Figure 2 It is an exploded view of the overall structure of the present invention.

[0022] Figure 3 It is an axonometric view of the vacuum switch part and the isolating switch part in the present invention.

[0023] Figure 4 It is a left side view of the vacuum switch part and the isolating switch part in the present invention.

[0024] Figure 5 It is a front view of the vacuum switch part and the isolating switch part in the present invention.

[0025] Figure 6 It is a rear view of the vacuum switch part and the isolating switch part in the present invention.

[0026] Figure 7 It is a top view of the vacuum switch part and the isolating switch part in the present invention.

[0027] Figure 8 It is an axonometric view of the transmission assembly in the present invention.

[0028] Fig. 9 The isometric view of the transmission assembly of the present invention without the slide cylinder.

[0029] Fig.10 It is a cross-sectional view of the third connecting rod in the present invention.

[0030] The accompanying drawings are marked as follows: 1. Equipment body; 101. Box body; 102. Back shell; 103. Connection assembly; 104. Air filling hole; 105. Air pressure gauge; 106. Explosion-proof pressure relief device; 1031, outgoing line connection bushing; 1032, incoming line connection bushing; 1033, main busbar; 1034, branch busbar; 2. Vacuum switch unit; 201. Side plate; 202. First frame; 203. First main shaft; 204. Transmission assembly; 205. Vacuum interrupter; 206. Soft copper busbar; 2041, first connecting rod; 2042, second connecting rod; 2043, third connecting rod; 2044, insulator; 2045, sleeve; 2046, elastic member; 3. Isolating switch unit; 301. Second frame; 302. Second main shaft; 303. Moving knife assembly; 304. Static contact; 305. Grounding assembly; 3031, swing rod; 3032, connecting rod; 3033, moving knife seat; 3034, moving knife blade; 3051, grounding horizontal row; 3052, grounding contact; 3053, grounding vertical row; 3054, grounding lead nut; 4. operating part; 401. first operating mechanism; 402. second operating mechanism; 5. Pressure equalizing cover; 6. Move the knife to pull the plate; 7. Slots; 8. Lifting plate; 9. Cabinet board. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Embodiment 1 See also Figures 1 to 10As shown, the core unit of the gas-insulated vacuum circuit breaker in the implementation of the present invention includes an equipment body 1, and the equipment body 1 includes a box 101. The box 101 is used to store insulating gas. A rear shell 102 is provided on one side of the box 101. A connecting component 103 is provided on the box 101. The connecting component 103 is used to connect external cables. The box 101 is also provided with an inflation hole 104, a pressure gauge 105 and an explosion-proof pressure relief device 106. The inflation hole 104 is used to inflate the box 101, the pressure gauge 105 is used to measure the gas pressure in the box 101, and the explosion-proof pressure relief device 106 is used to prevent the gas pressure in the box 101 from being too high.

[0033] It should be noted that the inflation hole 104, the pressure gauge 105 and the explosion-proof pressure relief device 106 are all prior arts, and their specific structures will not be described in detail here.

[0034] See also Figure 2 Figure 3 and Figure 7 As shown, it also includes a vacuum switch part 2, an isolating switch part 3 and an operating part 4. The vacuum switch part 2 includes two symmetrically distributed side plates 201. A first frame 202 is provided between the two side plates 201. A first main shaft 203 is provided on the first frame 202. The cross section of the first main shaft 203 is hexagonal. Three transmission components 204 are provided on the first main shaft 203. A vacuum interrupter 205 is provided at the bottom of each transmission component 204. The transmission component 204 is used to drive the vacuum interrupter 205 to work. A soft copper busbar 206 is provided on the top of each vacuum interrupter 205. Figure 4 and Figure 5 As shown, the isolating switch part 3 includes a second frame 301 fixed to the bottom of the side plate 201, a second main shaft 302 is provided on the second frame 301, three moving knife assemblies 303 are provided on the second main shaft 302, and three static contacts 304 and grounding assemblies 305 cooperating with the moving knife assemblies 303 are provided on the top and bottom of the second frame 301 respectively. When the moving knife assembly 303 contacts the static contact 304, the isolating switch part 3 is in a closed state, when the moving knife assembly 303 contacts the grounding assembly 305, the isolating switch part 3 is in a grounded state, and when the moving knife assembly 303 does not contact the static contact 304 and the grounding assembly 305, the isolating switch part 3 is in an open state; the operating part 4 includes a first operating mechanism 401 for controlling the rotation of the first main shaft 203 and a second operating mechanism 402 for controlling the rotation of the second main shaft 302.

[0035] It should be noted that the first operating mechanism 401 and the second operating mechanism 402 are both existing technologies, and both need to be connected to an existing control circuit for use, and their specific structures will not be described in detail here.

[0036] See also Figure 2As shown, the connection assembly 103 includes three outgoing line connection sleeves 1031 arranged at the top of the box 101 and three incoming line connection sleeves 1032 arranged at the bottom of the box 101, each outgoing line connection sleeve 1031 is provided with a main busbar 1033 at the bottom, and the bottom of each main busbar 1033 is electrically connected to the soft copper bus 206 on the corresponding side, and each incoming line connection sleeve 1032 is provided with a branch busbar 1034 located in the box 101, and the free end of each branch busbar 1034 is electrically connected to the movable knife assembly 303 on the corresponding side.

[0037] See also Figure 4 , Figure 5 and Figure 6 As shown, the multi-link transmission mechanism is driven by the first main shaft 203, and converts the rotary motion into linear motion through at least three levels of articulated links, thereby replacing the traditional cam mechanism to realize the opening and closing operations of the vacuum interrupter 205.

[0038] Specifically, the transmission assembly 204 includes a first connecting rod 2041 arranged on the first main shaft 203, and the free end of the first connecting rod 2041 is hinged with a vertical second connecting rod 2042, and three transverse third connecting rods 2043 are hinged on the first frame 202, and the free end of each third connecting rod 2043 is hinged with the free end of the second connecting rod 2042 on the corresponding side, and an insulator 2044 is provided on the top of each vacuum arc chamber 205, and a sleeve 2045 is slidably connected to the top of each insulator 2044, and each sleeve 2045 is movably connected to the middle part of the third connecting rod 2043 on the corresponding side, and an elastic member 2046 is provided between each sleeve 2045 and the insulator 2044, and the elastic member 2046 is used to maintain the pressure of the upper and lower contacts of the vacuum arc chamber 205.

[0039] See also Figure 6 As shown, the movable blade assembly 303 includes a swing rod 3031 arranged on the second main shaft 302, a connecting rod 3032 is arranged at the free end of the swing rod 3031, a movable blade seat 3033 is arranged on the second frame 301, three movable blades 3034 are hinged on the movable blade seat 3033, each movable blade 3034 can contact with the static contact 304 and the grounding assembly 305 on the corresponding side, each movable blade 3034 is hinged with the free end of the connecting rod 3032 on the corresponding side, and the contact surface between the movable blade 3034 and the grounding contact 3052 is provided with a silver coating. Figure 2 and Figure 6As shown, the grounding assembly 305 includes a grounding horizontal row 3051 arranged on the second frame 301, and three grounding contacts 3052 cooperating with the moving blade 3034 are provided on the grounding horizontal row 3051. The grounding contacts 3052 can contact the moving blade 3034 on the corresponding side. A grounding vertical row 3053 is provided at the bottom of the grounding horizontal row 3051, and a grounding lead-out nut 3054 located outside the box body 101 is provided at the free end of the grounding vertical row 3053. The grounding lead-out nut 3054 is used to realize the electrical connection between the grounding vertical row 3053 and the ground.

[0040] See also Figure 1 and Figure 2 As shown, a lifting plate 8 is provided on the top of the box body 101, and two symmetrically distributed cabinet merging plates 9 are provided on the rear shell 102. The lifting plate 8 and the cabinet merging plates 9 are used to fix the box body 101 on the electrical cabinet.

[0041] When in use, in the initial state, the moving blade 3034 is not in contact with the static contact 304 and the grounding contact 3052, and the upper and lower contacts of the vacuum arc extinguishing chamber 205 are in a separated state. The staff needs to fix the equipment body 1 on the electrical cabinet first. The screws in the prior art can be used to pass through the holes on the lifting plate 8 and the cabinet plate 9 to fix the box body 101 on the electrical cabinet, and then the incoming cable is electrically connected to the incoming connecting sleeve 1032, and the outgoing cable is electrically connected to the outgoing connecting sleeve 1031.

[0042] The staff energizes the incoming cable. At this time, the current in the incoming cable enters the branch bus 1034, and then enters the moving knife seat 3033 electrically connected to the branch bus 1034, and then reaches the moving blade 3034 hinged to the moving blade seat 3033. Since the moving blade 3034 is not in contact with the static contact 304 and the grounding contact 3052 at this time, the current cannot pass through the vacuum circuit breaker to reach the outgoing cable.

[0043] When the outgoing cable and the incoming cable need to be connected, the control circuit first controls the second operating mechanism 402 to work, the second operating mechanism 402 drives the second main shaft 302 to rotate, the second main shaft 302 drives multiple rocker arms 3031 to swing, the rocker arms 3031 drive the connecting rods 3032 hinged thereto to move, the connecting rods 3032 drive the moving blades 3034 on the corresponding side to swing toward the direction close to the static contact 304, when the moving blades 3034 contact the static contact 304, the current in the incoming cable passes through the moving blades 3034 and reaches the static contact 304.

[0044] The control circuit controls the second operating mechanism 402 to stop working. At this time, the second main shaft 302 stops rotating, and the movable blade 3034 keeps in contact with the static contact 304 on the corresponding side. The control circuit controls the first operating mechanism 401 to work. The first operating mechanism 401 drives the first main shaft 203 to rotate. The first main shaft 203 drives multiple first connecting rods 2041 to swing. The first connecting rod 2041 drives the second connecting rod 2042 hinged thereto to swing. The second connecting rod 2042 drives the third connecting rod 2043 to swing toward the direction close to the vacuum arc chamber 205. The third connecting rod 2043 drives the sleeve 2045 movably connected thereto to move toward the direction close to the vacuum arc chamber 205. The first connecting rod 2041, the second connecting rod 2042 and the third connecting rod 2043 convert the rotational motion of the first main shaft 203 into a linear motion of the sleeve 2045. Compared with the cam-driven method in the prior art, the volume is smaller while achieving the same stroke, and the mass of the structure is reduced.

[0045] The sleeve 2045 squeezes the elastic member 2046 downward, and the other end of the elastic member 2046 drives the insulator 2044 to move downward. The insulator 2044 drives the contact on the upper side of the vacuum arc chamber 205 to move downward and contact the contact on the lower side. The vacuum arc chamber 205 can extinguish the arc generated before the contact. At this time, the control circuit controls the first operating mechanism 401 to stop working, and the first main shaft 203 stops rotating. The elastic member 2046 keeps a certain pressure on the contacts on the upper and lower sides of the vacuum arc chamber 205, so that the current in the incoming cable can stably pass through the vacuum arc chamber 205 and be transmitted to the soft copper busbar 206, and then flow to the main busbar 1033 electrically connected to it, and finally enter the outgoing cable electrically connected to the outgoing connecting sleeve 1031.

[0046] When encountering an emergency, the control circuit first controls the first operating mechanism 401 to work, and the first operating mechanism 401 drives the vacuum arc chamber 205 to open the gate through the transmission component 204, and the vacuum switch part 2 is disconnected, and then drives the second operating mechanism 402 to work, and the second operating mechanism 402 drives the second main shaft 302 to rotate, and the second main shaft 302 drives multiple rocker arms 3031 to swing, and the rocker arms 3031 drive the connecting rods 3032 to move, and the connecting rods 3032 drive the moving blades 3034 on the corresponding side to swing toward the grounding contact 3052. When the moving blades 3034 contact the grounding contact 3052, the current in the incoming cable enters the grounding contact 3052 through the moving blades 3034, and then enters the grounding horizontal row 3051 and the grounding vertical row 3053, and finally flows to the ground through the grounding lead-out nut 3054, thereby protecting the circuit.

[0047] Under normal circumstances, when the circuit needs to be disconnected, the control circuit needs to first control the first operating mechanism 401 to work, and then control the second operating mechanism 402 to work. The first operating mechanism 401 first disconnects the contacts on the upper and lower sides of the vacuum arc extinguishing chamber 205. The vacuum arc extinguishing chamber 205 can extinguish the arc generated after the disconnection. The second operating mechanism 402 separates the moving blade 3034 from the static contact 304. At this time, the circuit is in a disconnected state.

[0048] Embodiment 2 It was found in actual use that when the third connecting rod 2043 drives the sleeve 2045 to move toward the direction close to the vacuum arc chamber 205, since the position of the movable connection between the sleeve 2045 and the third connecting rod 2043 is in the middle of the third connecting rod 2043, the downward pressure applied by the second connecting rod 2042 to the second connecting rod 2042 can be applied exponentially to the connection between the sleeve 2045 and the third connecting rod 2043. Since the contact area between the connecting shaft and the third connecting rod 2043 is small, the shaft may easily break, affecting the normal use of the vacuum circuit breaker and may also cause a dangerous situation. Further improvements are made on the basis of the above embodiments.

[0049] Reference Figure 8 , Fig. 9 and Fig.10 As shown, a slide groove is provided in the middle of each third connecting rod 2043, and two short shafts facing each other front and back are provided on each sleeve 2045. The short shafts are located in the slide grooves on the corresponding sides. A slide cylinder is sleeved in the middle of the third connecting rod 2043, and an outer cylinder passing through the slide groove is provided on the slide cylinder. The outer cylinder is sleeved on the outside of the short shaft. A plurality of reinforcing ribs evenly distributed along the circumferential direction of the short shaft are provided between the slide cylinder and the outer cylinder. The reinforcing ribs are used to enhance the connection strength between the slide cylinder and the outer cylinder. The slide cylinder and the outer cylinder are used to increase the contact area between the third connecting rod 2043 and the short shaft, so as to avoid excessive pressure on the local part of the short shaft and cause it to break.

[0050] On the basis of the above embodiment, when the third connecting rod 2043 swings toward the direction close to the vacuum arc extinguishing chamber 205, the third connecting rod 2043 drives the slide cylinder to swing synchronously, the slide cylinder drives the outer cylinder to swing, and the outer cylinder drives the short shaft to swing. Since the trajectory of the third connecting rod 2043 is an arc, and the sleeve 2045 can only move in a straight line, the movement trajectory of the short shaft fixed to the sleeve 2045 is also a straight line. When moving, the short shaft and the outer cylinder will slide to a certain extent in the slide groove, and the outer cylinder drives the slide cylinder to slide along the length direction of the third connecting rod 2043, and the outer cylinder and the slide cylinder are in a disguised state. The contact area between the short shaft and the third connecting rod 2043 is increased to prevent the short shaft from being broken due to excessive local force. In addition, the sliding groove on the third connecting rod 2043 will affect the strength of the third connecting rod 2043. The sleeve 2045 is sleeved on the outer surface of the third connecting rod 2043, and can wrap the third connecting rod 2043 near the sliding groove, thereby increasing the strength of the third connecting rod 2043 and preventing the third connecting rod 2043 from breaking. A plurality of reinforcing ribs are also arranged between the sleeve 2045 and the sliding cylinder, which can improve the overall structural strength and extend the service life of the vacuum circuit breaker.

[0051] Embodiment 3 It was found in actual use that when the movable blade 3034 swings in the direction close to the static contact 304, due to the fast swinging speed of the movable blade 3034, a collision will occur when the movable blade 3034 contacts the static contact 304, which may cause over-closing phenomenon, and the electric field distribution in the space around the movable blade 3034 and the side plate 201 is uneven, affecting the overall insulation performance of the switch. Further improvements are made on the basis of the above-mentioned embodiment.

[0052] See also Figure 5 and Figure 6 As shown, a shock-absorbing material is provided on the second main shaft 302, and each movable blade 3034 is provided with a movable blade pull plate 6 hinged to the connecting rod 3032, and a protrusion is provided on the movable blade pull plate 6. The movable blade pull plate 6 and the shock-absorbing material are used to absorb the kinetic energy generated by the collision when the isolating switch part 3 is closed.

[0053] See also Figure 3 and Figure 5 As shown, the voltage grading structure includes a voltage grading cover 5 covering the movable blade assembly 303 and the static contact 304, and slots 7 opened between the fixing points of the metal parts, which are used to enhance the uniformity of the electric field and the creepage distance.

[0054] Specifically, the static contact 304 and the movable knife seat 3033 are both provided with a voltage grading cover 5, and the voltage grading cover 5 is used to enhance the insulation performance of the isolating switch part 3; A plurality of slots 7 are provided on the side plate 201 . Each slot 7 is located between adjacent fixing points of metal parts. The plurality of slots 7 are used to increase the creepage distance.

[0055] A corrugated electric field grading layer is provided on the surface of the grading cover 5 , and the thickness of the grading cover 5 decreases along the electric field intensity gradient direction, and the edges of the slots 7 are rounded.

[0056] On the basis of the above embodiment, during use, when the movable blade 3034 swings toward the direction close to the static contact 304, the movable blade pull plate 6 will also swing. When the movable blade 3034 contacts the static contact 304, the protrusion on the movable blade pull plate 6 contacts the shock-absorbing material on the second main shaft 302, which can not only avoid over-closing, but also absorb the kinetic energy generated by the collision during closing, reduce rebound, and avoid poor contact between the movable blade 3034 and the static contact 304.

[0057] Slots 7 are provided between every two adjacent metal parts on the side plate 201, which can increase the creepage distance and help eliminate the influence of arc.

[0058] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A core unit for a gas-insulated vacuum circuit breaker, comprising a device body, a first main shaft and a vacuum interrupter, characterized in that: Also includes: The multi-link transmission mechanism is driven by the first main shaft and converts the rotary motion into linear motion through at least three levels of articulated links, replacing the traditional cam mechanism to realize the opening and closing operations of the vacuum interrupter; The voltage grading structure includes a voltage grading cover covering the moving blade assembly and the static contact, and slots opened between the fixing points of the metal parts, which are used to enhance the uniformity of the electric field and the creepage distance.

2. The vacuum circuit breaker core unit according to claim 1, characterized in that: The multi-link transmission mechanism includes a first link fixedly connected to the first main shaft, a second link hinged to the end of the first link, and a third link connecting the second link and the vacuum arc chamber. The middle part of the third link is slidably matched with the sleeve short shaft through a sliding groove.

3. The vacuum circuit breaker core unit according to claim 2, characterized in that: An outer cylinder with reinforcing ribs is embedded in the sliding groove of the third connecting rod, and the outer cylinder and the short axis of the sleeve form a surface contact structure for enhancing the connection strength between the outer cylinder and the sleeve.

4. The vacuum circuit breaker core unit according to claim 1, characterized in that: The surface of the voltage grading cover is provided with a corrugated electric field voltage grading layer, and the thickness of the voltage grading cover decreases along the direction of the electric field intensity gradient.

5. The vacuum circuit breaker core unit according to claim 1, characterized in that: The slot hole edge adopts rounded transition.

6. The vacuum circuit breaker core unit according to claim 1, characterized in that: The movable blade assembly comprises a swing rod hinged on the second main shaft, the end of the swing rod drives three movable blades through a connecting rod, and the contact surface between the movable blade and the grounding contact is provided with a silver coating.

7. The vacuum circuit breaker core unit according to claim 1, characterized in that: The cross section of the first main axis is hexagonal.

8. The vacuum circuit breaker core unit according to claim 1, characterized in that: A grounding horizontal bar is integrated at the bottom of the device body, and the grounding horizontal bar is connected to an external grounding terminal through an L-shaped grounding vertical bar.

9. The vacuum circuit breaker core unit according to claim 1, characterized in that: A lifting plate is provided on the top of the equipment body.

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