CN117877934A

CN117877934A - Circuit breaker

Info

Publication number: CN117877934A
Application number: CN202410013829.9A
Authority: CN
Inventors: 韦尚靖; 刘亚南; 张莹; 李俐; 徐永富; 李建鹏
Original assignee: Shanghai Chint Intelligent Technology Co Ltd
Current assignee: Shanghai Chint Intelligent Technology Co Ltd
Priority date: 2024-01-04
Filing date: 2024-01-04
Publication date: 2024-04-12

Abstract

The circuit breaker comprises a shell, an operating mechanism and conductive systems, wherein a traction rod is rotatably assembled on one side of the operating mechanism, each conductive system comprises a contact mechanism, an arc extinguishing system and a thermomagnetic tripping mechanism, the contact mechanisms of the conductive systems are in driving connection with the operating mechanism, the contact mechanisms and the arc extinguishing systems are sequentially arranged in the shell in a layered mode, each contact mechanism comprises two moving contact assemblies which are rotatably assembled, each moving contact assembly is driven by the operating mechanism to be in opposite rotating contact or back rotating separation, an arc generated when the contact mechanisms are matched with each other to be extinguished by the corresponding arc extinguishing system to break, and the thermomagnetic tripping mechanisms are arranged in the shell between the corresponding arc extinguishing systems and the corresponding operating member and drive the traction rod to trigger the corresponding operating mechanism to trip. According to the invention, the operating mechanism, the contact mechanism and the arc extinguishing system are sequentially arranged in layers, and the thermomagnetic tripping mechanism is arranged between the arc extinguishing system and the operating piece, so that the arc extinguishing system has a larger assembly space, and the overall breaking performance of the circuit breaker is improved.

Description

Circuit breaker

Technical Field

The invention relates to the field of piezoelectric devices, in particular to a circuit breaker.

Background

A circuit breaker is a switching device for switching off and on a load circuit, and switching off a fault circuit to prevent an accident from being enlarged, thereby securing a safe operation of the load circuit. Along with the development and application of new energy, higher requirements are put forward on the reliable breaking performance of the circuit breaker in order to adapt to the continuously improved working voltage of the new energy system. However, most of the existing circuit breakers are left-right distributed structures, namely arc extinguishing chambers and thermomagnetic tripping mechanisms are respectively arranged on two opposite sides in a shell, an operating mechanism and a contact mechanism are arranged in the middle of the shell and limited by the space in the shell, and the circuit breakers generally adopt methods for improving breaking capacity, such as increasing the number and the area of arc extinguishing bars and increasing the contact opening distance, but the breaking capacity improving effect is limited due to the limitation of the size and the single-breakpoint structure of the circuit breaker.

Disclosure of Invention

The invention aims to overcome at least one defect of the prior art and provides a circuit breaker with simple structure, high reliability and good sectioning capability.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the invention provides a circuit breaker, which comprises a shell, wherein an operating mechanism and at least one conductive system are arranged in the shell, a traction rod is rotatably assembled on one side of the operating mechanism, each conductive system comprises a contact mechanism, an arc extinguishing system and a thermomagnetic tripping mechanism, the contact mechanism of at least one conductive system is in driving connection with the operating mechanism, an operating piece connected with the operating mechanism stretches out of the shell, the operating mechanism, the contact mechanism and the arc extinguishing system are sequentially arranged in the shell in a layered manner, the contact mechanism comprises two movable contact assemblies which are rotatably assembled, the operating mechanism drives the two movable contact assemblies to be in opposite-direction rotary contact or back-direction rotary separation, the thermomagnetic tripping mechanism is arranged in the shell between the arc extinguishing system and the operating piece and drives the traction rod to trigger the operating mechanism to trip.

Preferably, the shell is internally divided into a first assembly cavity, a second assembly cavity and a third assembly cavity in sequence, an operating mechanism and a traction rod are rotationally arranged in the first assembly cavity, an arc extinguishing system is arranged in the third assembly cavity, and the thermomagnetic tripping mechanism is arranged in the first assembly cavity or arranged in the second assembly cavity to extend into the first assembly cavity.

Preferably, one end of the two moving contact assemblies is rotatably connected to the joint of the first assembly cavity and the second assembly cavity, and the other ends of the two moving contact assemblies extend from the second assembly cavity to the third assembly cavity and rotate in the arc extinguishing cavity of the arc extinguishing system.

Preferably, a blocking part is arranged at the joint of the first assembly cavity and the second assembly cavity, and the blocking part is positioned between the two moving contact assemblies and used for limiting the moving contact assemblies.

Preferably, the contact mechanism further comprises an auxiliary contact, wherein the auxiliary contact is fixedly arranged between two moving contact assemblies, and each moving contact assembly is respectively contacted with or separated from one side of the auxiliary contact.

Preferably, one end of the auxiliary contact is fixedly connected with the shell, and the other end of the auxiliary contact penetrates through the middle part of the arc extinguishing system to be matched with the two moving contact assemblies respectively.

Preferably, the two moving contact assemblies are connected through a link mechanism, and the link mechanism at least comprises one link rod hinged between the two moving contact assemblies.

Preferably, the two moving contact assemblies are connected through a gear transmission mechanism, and the gear transmission mechanism at least comprises two gear parts which are connected in a meshed mode.

Preferably, the arc extinguishing system comprises an arc extinguishing chamber, an opening of the arc extinguishing chamber faces the contact mechanism, the moving contact assembly extends into an arc extinguishing cavity of the arc extinguishing chamber from the opening, and a plurality of arc extinguishing grid plates used for arc extinguishing are arranged in the arc extinguishing cavity.

Preferably, a plurality of arc extinguishing bars are arranged along the inner side of the arc extinguishing cavity in a surrounding mode, the arc extinguishing bars are divided into a first bar group and two second bar groups, the first bar group is opposite to the opening at intervals, and the two second bar groups are respectively arranged on two opposite sides of the opening.

Preferably, at least one pair of exhaust ports are formed in two opposite sides of the shell, the arc extinguishing system is correspondingly arranged in the shell between the pair of exhaust ports, the exhaust ports are covered with arc extinguishing pieces, and the inner side walls of the shell connected between the pair of exhaust ports are provided with flow guiding parts.

Preferably, each conductive system further comprises a pair of wiring assemblies arranged at intervals, two movable contact assemblies are arranged between a pair of wiring assemblies side by side and are respectively electrically connected with adjacent wiring assemblies, and the thermomagnetic tripping mechanism is arranged between one movable contact assembly and one wiring assembly.

Preferably, the wiring assembly comprises a wiring terminal and a connecting plate, wherein two ends of the connecting plate are respectively and electrically connected with the wiring terminal and the contact mechanism, and the connecting plate between the thermomagnetic tripping mechanism and the adjacent wiring terminal is connected with the thermomagnetic tripping mechanism and serves as a part of the thermomagnetic tripping mechanism.

Preferably, the thermomagnetic tripping mechanism comprises a magnetic tripping device and a thermal tripping device, the magnetic tripping device comprises a magnetic yoke, an armature bracket, an armature and a reset piece, the magnetic yoke is opposite to the armature at intervals, one end of the armature is hinged on the armature bracket, the other end of the armature is matched with a traction rod, and the reset piece is connected between the armature bracket and the armature; the thermal trip device comprises a bimetallic strip and a connecting plate, wherein one end of the connecting plate is connected with the fixed end of the bimetallic strip and the magnetic yoke respectively, the movable end of the bimetallic strip is provided with an adjusting screw, and the adjusting screw is matched with the traction rod.

Preferably, the shell comprises a base, a first supporting plate, a second supporting plate and a cover body which are assembled in sequence, wherein a first assembly cavity is formed between the cover body and the second supporting plate at intervals, a second assembly cavity is formed between the first supporting plate and the second supporting plate at intervals, and the base and the first supporting plate are matched to form a third assembly cavity.

Preferably, the inner shell is arranged in the third assembly cavity, an arc extinguishing chamber of an arc extinguishing system is arranged in the inner shell, a second avoiding groove is formed in the inner shell, and the second avoiding groove is communicated with the first avoiding groove arranged on the first supporting plate and an opening of the arc extinguishing cavity.

Preferably, the thermomagnetic tripping mechanism is arranged between the cover body and the second supporting plate, or the thermomagnetic tripping mechanism is arranged between the first supporting plate and the second supporting plate and passes through the first supporting plate to be matched with the traction rod.

According to the circuit breaker, the operating mechanism, the contact mechanism and the arc extinguishing system are sequentially arranged in a layered mode, the contact mechanism is contacted or separated by adopting two movable contact assemblies arranged side by side to realize opening and closing of the contact mechanism, the opening distance of the contact mechanism is increased, the opening speed of the contact mechanism can be increased in multiple, and meanwhile, the thermomagnetic tripping mechanism is arranged between the arc extinguishing system and the operating member, so that the arc extinguishing system has a larger assembly space, the layout is reasonable, and the integral breaking performance of the circuit breaker is improved.

In addition, divide into three assembly chamber in the shell, wherein thermomagnetic tripping device and arc extinguishing system set up in different assembly chamber, thermomagnetic tripping device sets up the position more nimble.

In addition, two moving contact assemblies are matched in the arc extinguishing cavity, so that an arc during breaking is directly generated in the arc extinguishing cavity, the arc striking and extinguishing efficiency is improved, and meanwhile, the inner space is saved.

Drawings

Fig. 1 is a schematic structural view of a circuit breaker of the present invention;

Fig. 2 is a schematic view of the internal layering of the circuit breaker of the present invention;

FIG. 3 is a schematic view of an exploded construction of the housing of the present invention;

fig. 4 is a schematic view of an exploded structure of the circuit breaker of the present invention;

fig. 5 is a schematic view of the internal structure of the circuit breaker of the present invention;

fig. 6 is a schematic structural diagram (including a diversion slope) of the circuit breaker of the present invention during closing;

fig. 7 is a schematic view of the structure of the circuit breaker of the present invention at the time of breaking;

fig. 8 is a schematic diagram of the circuit breaker of the present invention in a closed configuration;

fig. 9 is a schematic diagram of the circuit breaker of the present invention (including auxiliary contacts and auxiliary contacts) in a breaking operation;

fig. 10 is a schematic view of the circuit breaker of the present invention (including auxiliary contacts and auxiliary contacts) during closing;

fig. 11 is a schematic diagram of the circuit breaker of the present invention (including auxiliary contacts) during closing;

FIG. 12 is a schematic view of the structure of the contact mechanism of the present invention (including the first link) when the contact mechanism is separately gated;

FIG. 13 is a schematic view of the structure of the contact mechanism of the present invention (including a first link) when the contact mechanism is closed;

FIG. 14 is a schematic view of the structure of the contact mechanism of the present invention (including a second link) when the contact mechanism is opened;

FIG. 15 is a schematic view of the structure of the contact mechanism of the present invention (including a second link) when the contact mechanism is closed;

FIG. 16 is a schematic illustration of the mating of the guide, guide slot and second link of the present invention;

FIG. 17 is a schematic view of the structure of the contact mechanism of the present invention (with incomplete gears) when the contact mechanism is opened;

FIG. 18 is a schematic view of the structure of the contact mechanism of the present invention (with incomplete gears) when the contact mechanism is closed;

FIG. 19 is a schematic view of the structure of the contact mechanism of the present invention (including gears) when the contact mechanism is opened;

FIG. 20 is a schematic view of the structure (including gears) of the contact mechanism of the present invention when the contact mechanism is closed;

FIG. 21 is a schematic view of the structure of the contact mechanism of the present invention;

FIG. 22 is a schematic view of a shaft according to the present invention;

FIG. 23 is a schematic view of the structure of the movable contact assembly and the spring assembly of the present invention;

FIG. 24 is an exploded view of the movable contact assembly and spring assembly of the present invention;

FIG. 25 is an exploded view of a moving contact assembly and spring assembly of the present invention;

FIG. 26 is a schematic view of another embodiment of an elastic assembly of the present invention;

FIG. 27 is a schematic view of a connecting rod assembly and moving contact assembly of the present invention;

FIG. 28 is a cross-sectional view of a moving contact assembly of the present invention;

FIG. 29 is a second cross-sectional view of the moving contact assembly of the present invention;

FIG. 30 is a cross-sectional view of the moving contact assembly of the present invention when the moving contact assembly is opened;

FIG. 31 is a cross-sectional view of the moving contact assembly of the present invention during closing;

FIG. 32 is a cross-sectional view of the present invention with the drive portion pushing the second end of the resilient assembly away from the third stop portion;

FIG. 33 is a cross-sectional view of the present invention with the drive portion pushing the second end of the resilient member about to engage the second stop portion;

FIG. 34 is a cross-sectional view of the second end of the spring assembly of the present invention captured in the second capture portion;

fig. 35 is a schematic structural view of an arc chute according to the present invention;

fig. 36 is a schematic view showing an exploded structure of the arc extinguishing chamber of the present invention;

FIG. 37 is a schematic view of the structure of a gate stack (including a connecting gate) according to the present invention;

fig. 38 is a cross-sectional view of an arc chute of the present invention (including a transition gate stack);

fig. 39 is a schematic diagram of an arc chute of the present invention-a first embodiment of an arc chute;

fig. 40 is a schematic diagram of an arc chute according to the present invention (first embodiment of arc chute);

fig. 41 is a schematic diagram of an arc chute of the present invention, three (first embodiment of arc chute);

fig. 42 is a schematic view of an arc chute (second embodiment of arc extinguishing system) in the present invention;

fig. 43 is a schematic view of an arc chute (third embodiment of arc extinguishing system) in the present invention;

FIG. 44 is an exploded view of 43;

reference numerals:

1-housing, 101-first assembly chamber, 102-second assembly chamber, 103-third assembly chamber, 104-exhaust port, 105-guide section, 1051-guide slope, 1 a-base, 1a 1-partition, 1 b-first support plate, 1b 1-first escape slot, 1 c-second support plate, 1c 1-blocking section, 1 d-cover, 2-operating mechanism, 20-traction lever, 21-operating member, 22-link assembly, 3-contact mechanism, 311-first link, 312-second link, 313-guide, 3131-guide slot, 314-connecting shaft, 321-incomplete gear, 322-gear, 33-spindle, 330-assembly slot, 3301-first limiting wall, 3302-second limiting wall, 331-third limit part, 3311-reset surface, 3312-abutting surface, 34-moving contact, 341-connecting part, 3411-first abutting surface, 3412-second abutting surface, 342-contact arm, 343-moving contact, 345-first limit part, 346-second limit part, 347-driving part, 35-contact spring, 350-limit interval, 351-tension spring, 352-first elastic arm, 353-hooking part, 36-spring link, 37-contact bracket, 38-auxiliary contact, 381-auxiliary contact, 39-assembly shaft, 4-arc extinguishing system, 4 a-arc extinguishing chamber, 40-arc extinguishing chamber, 41-opening, 42-first grid set, 421-split grid set, 42 a-assembly gap, 43-second grid set, 44-connection grid plates, 45-transition grid plate sets, 46-arc striking angles, 47-magnets, 48-gas generating pieces, 481-mounting grooves, 49-arc extinguishing pieces, 5-thermomagnetic tripping mechanisms, 51-bimetallic strips, 52-armatures, 6-wiring assemblies, 61-wiring terminals and 62-connecting plates.

Detailed Description

Embodiments of the circuit breaker of the present invention are further described below with reference to the examples shown in the drawings. The circuit breaker of the present invention is not limited to the description of the following embodiments.

As shown in fig. 1 and 4, the circuit breaker comprises a shell 1, an operating mechanism 2 and at least one conductive system are arranged in the shell 1, the operating mechanism 2 is rotationally assembled in the shell 1, an operating piece 21 connected to the operating mechanism 2 extends out of the shell 1, a traction rod 20 is rotationally assembled at one side of the operating mechanism 2, the traction rod 20 triggers the operating mechanism 2 to trip, each conductive system comprises a contact mechanism 3, an arc extinguishing system 4 and a thermomagnetic tripping mechanism 5, the contact mechanism 3 is used for controlling the on-off of a main circuit in each conductive system, the contact mechanism 3 of at least one conductive system is in driving connection with the operating mechanism 2, the movable contact assemblies of two adjacent conductive systems are in linkage connection, and the contact mechanisms 3 of each conductive system can be driven to synchronously switch on-off by driving the operating mechanism 2; the arc extinguishing system 4 is cooperatively arranged on one side of the contact mechanism 3 and is used for extinguishing an electric arc generated when the contact mechanism 3 breaks, and tail gas generated by arc extinguishing of the arc extinguishing system 4 is discharged from an exhaust port 104 arranged on the shell 1; the thermo-magnetic tripping mechanism 5 is connected to the main circuit, and when the main circuit has a short circuit or overload fault, the thermo-magnetic tripping mechanism 5 acts and triggers the operating mechanism 2 to trip through the driving traction rod 20.

As shown in fig. 4, the contact mechanism 3 includes a moving contact assembly assembled by rotation, the moving contact assembly in at least one conductive system is in driving connection with the operating mechanism 2, each moving contact assembly includes a rotating shaft 33 and a moving contact 34, the rotating shaft 33 is assembled by coaxial rotation with the moving contact 34 and in driving fit, and the operating mechanism 2 drives the moving contact assembly to rotate in a closing direction or a separating direction.

The improvement point of the application lies in that, as shown in fig. 1-4, the operating mechanism 2, the contact mechanism 3 and the arc extinguishing system 4 are sequentially arranged in the shell 1 in a layering manner, the contact mechanism 3 comprises two moving contact assemblies assembled in a rotating manner, the operating mechanism 2 drives the two moving contact assemblies to be in opposite rotating contact or back rotating separation, the arc generated when the arc extinguishing system 4 is matched with the arc extinguishing mechanism 3 to be broken is extinguished, the thermomagnetic tripping mechanism 5 is arranged in the shell 1 between the arc extinguishing system 4 and the operating piece 21, and the thermomagnetic tripping mechanism 5 drives the traction rod 20 to trigger the operating mechanism 2 to trip.

So, through setting up operating device 2, contact mechanism 3 and arc extinguishing system 4 layering in proper order, contact mechanism 3 adopts two moving contact subassembly contacts or the separation that set up side by side in order to realize the divide-shut brake of contact mechanism 3, has increased the opening distance of contact mechanism 3, also can doubly improve the opening speed of contact mechanism 3, simultaneously, thermomagnetic tripping device 5 sets up between arc extinguishing system 4 and operating piece 21, makes arc extinguishing system 4 possess bigger assembly space, and is rationally distributed, has promoted the holistic breaking property of circuit breaker.

Specifically, as shown in fig. 2-4, the interior of the housing 1 is divided into a first assembly cavity 101, a second assembly cavity 102 and a third assembly cavity 103 in sequence, the operating mechanism 2 and the traction rod 20 are rotationally arranged in the first assembly cavity 101, the contact mechanism 3 is arranged in the second assembly cavity 102, the thermomagnetic tripping mechanism 5 is arranged in the first assembly cavity 101, or the thermomagnetic tripping mechanism 5 is arranged in the second assembly cavity 102 and extends into the first assembly cavity 101, the arc extinguishing system 4 is arranged in the third assembly cavity 103, the arrangement position of the thermomagnetic tripping mechanism 5 is relatively flexible, and the thermomagnetic tripping mechanism and the arc extinguishing system 4 are respectively positioned in different assembly cavities, so that mutual interference can be avoided.

Further, the two moving contact assemblies extend from the second assembly cavity 102 to the third assembly cavity 103, and correspondingly, the two moving contact assemblies extend to the arc extinguishing cavity 4a of the arc extinguishing system 4, so that the two moving contact assemblies complete switching on or switching off in the arc extinguishing cavity 4a, and an electric arc generated when the two moving contact assemblies are switched off is directly located in the arc extinguishing cavity 4a, thereby being beneficial to improving the arc striking and extinguishing efficiency of the arc extinguishing system 4.

A specific embodiment of a circuit breaker is provided in connection with fig. 1-44.

As shown in fig. 1 to 6, the circuit breaker includes a housing 1, a height direction of the housing 1 is a first direction, that is, an up-down direction in fig. 5 and 6, a length direction of the housing 1 is a second direction, that is, a left-right direction in fig. 5 and 6, and a thickness direction of the housing 1 is a third direction, that is, a direction perpendicular to a paper surface in fig. 5 and 6, and the first direction, the second direction and the third direction are perpendicular to each other, respectively.

As shown in fig. 5 to 11, an operating mechanism 2 and at least one conductive system are provided in a housing 1, wherein the operating mechanism 2 and the conductive system are stacked in a first direction, an operating piece 21 connected to the operating mechanism 2 extends out of the housing 1, one side of the operating mechanism 2 is rotatably provided with a traction rod 20, that is, the traction rod 20 and the operating mechanism 2 are arranged side by side in a second direction, and when two or more conductive systems are provided in the housing 1, two adjacent conductive systems are arranged side by side in a third direction; each conductive system comprises a pair of wire assemblies 6, a contact mechanism 3, an arc extinguishing system 4 and a thermomagnetic tripping mechanism 5, wherein the pair of wire assemblies 6 are arranged at intervals in the second direction, the contact mechanism 3 is positioned between the pair of wire assemblies 6 and is respectively and electrically connected with the pair of wire assemblies 6, the contact mechanism 3 of at least one conductive system is in driving connection with the operating mechanism 2, and the main circuit of each conductive system is connected or disconnected by driving the operating mechanism 2 through the contact mechanism 3; the thermomagnetic tripping mechanism 5 is positioned between the contact mechanism 3 and one wiring assembly 6 and connected to the main circuit, and when the main circuit has short circuit or overload fault, the thermomagnetic tripping mechanism 5 drives the traction rod 20 to rotate, so that the operating mechanism 2 is tripped; the arc extinguishing system 4 is cooperatively arranged on one side of the contact mechanism 3 and is used for extinguishing an arc generated when the contact mechanism 3 breaks.

As shown in fig. 2 to 11, the operating mechanism 2, the contact mechanism 3 and the arc extinguishing system 4 are sequentially stacked in the housing 1, in this embodiment, the operating mechanism 2, the contact mechanism 3 and the arc extinguishing system 4 are sequentially stacked in the first direction, that is, the space in the housing 1 is sequentially divided into a first assembly cavity 101, a second assembly cavity 102 and a third assembly cavity 103 which are stacked in the first direction, the operating mechanism 2 and the traction rod 20 are rotatably disposed in the first assembly cavity 101, the operating mechanism 2 and the traction rod 20 can be used in the prior art, the operating member 21 extends from a side far from the third assembly cavity 103 to the outside of the housing 1 for driving the operating mechanism 2, and the link assembly 22 of the operating mechanism 2 extends into the second assembly cavity 102 for driving the contact mechanism 3; the thermo-magnetic tripping mechanism 5 is arranged in the first assembling cavity 101, which is beneficial to being matched with the traction rod 20, of course, the thermo-magnetic tripping mechanism 5 can also be arranged in the second assembling cavity 102, so that the thermo-magnetic tripping mechanism 5 extends into the first assembling cavity 101 to be matched with the traction rod 20; the arc extinguishing system 4 is independently arranged in the third assembly cavity 103, so that the arc extinguishing system 4 has more assembly space, the arc extinguishing space is increased, and the mutual interference of the thermomagnetic tripping mechanism 5 and the arc extinguishing system 4 in the same assembly cavity is avoided.

In this embodiment, as shown in fig. 4 and 5, a traction rod 20 matched with the operation mechanism 2 is rotatably arranged at one side of the operation mechanism 2, the operation mechanism 2 comprises a pair of brackets, a rocker arm, a jump button, a lock catch, a rebuckle, a connecting rod assembly 22 and a linkage piece, the pair of brackets are arranged in the shell 1 at intervals, preferably, the space between the pair of brackets corresponds to a conductive system positioned at a middle position, or all the conductive systems correspond to the space between the pair of brackets, the rocker arm is rotatably supported on the pair of brackets and provided with an operation piece 21 on the rocker arm, the operation piece 21 extends out of the shell 1 and is used for driving the circuit breaker to perform opening and closing actions, the rocker arm is connected with a rocker arm shaft arranged on the connecting rod assembly 22 through a rocker arm spring, and the jump button, the lock catch, the rebuckle and the traction rod 20 are respectively rotatably assembled at the inner upper parts of the pair of brackets, wherein the jump button and the lock catch are in snap fit, and the rebuckle are in limit fit; as shown in fig. 3, 4 and 5, the link assembly 22 includes a first transmission rod and a second transmission rod, a rocker shaft is disposed at one end of the second transmission rod, the first transmission rod is hinged to one end of the second transmission rod through the rocker shaft, the other end of the first transmission rod is connected with the trip buckle, and the other end of the second transmission rod is connected with the rotating shaft 33 in the moving contact assembly.

As shown in fig. 5-23, in this embodiment, the contact mechanism 3 includes two moving contact assemblies assembled by side rotation, where the two moving contact assemblies are connected in linkage through a link mechanism or a gear transmission mechanism, one moving contact assembly is connected with the operating mechanism 2 in a driving manner, and the operating mechanism 2 drives the two moving contact assemblies to rotate in opposite directions to contact or rotate in opposite directions to separate, so that the two moving contact assemblies synchronously and stably rotate in opposite directions or rotate in opposite directions, and the two moving contact assemblies synchronously rotate at the same rotation angle, thereby increasing the opening distance of the contact mechanism 3, and doubling the opening speed of the contact mechanism 3, so as to facilitate the improvement of the breaking performance of the circuit breaker.

Specifically, each moving contact assembly comprises a rotating shaft 33 and a moving contact 34, wherein the rotating shaft 33 is rotatably arranged in a second assembling cavity 102 of the shell 1, the moving contact 34 is coaxially assembled and in driving fit with the rotating shaft 33, as shown in fig. 10 and 12-15, the connecting rod mechanism comprises at least one connecting rod hinged between the two rotating shafts 33, the structure is simple, the linkage effect is good, further, as shown in fig. 10 and 16, the connecting rod mechanism further comprises a guide member 313, the guide member 313 is provided with a guide groove 3131, and the connecting rod mechanism is in sliding fit with the guide groove 3131 to limit the moving track of the connecting rod; as shown in fig. 11, 17 to 20, the gear transmission mechanism includes two gear parts engaged with each other, each gear part is provided along a circumferential side wall of one rotating shaft 33, the gear parts may be provided by a gear 322 (see fig. 19 and 20) or an incomplete gear 321 (see fig. 11, 17 and 18) fixed to the rotating shaft 33, for example, each rotating shaft 33 is provided with one incomplete gear 321, or each rotating shaft 33 is provided with one gear 322, or one rotating shaft 33 is provided with an incomplete gear 321, and the other rotating shaft 33 is provided with a gear 322, however, the gear parts may be integrally formed by the rotating shafts 33, for example, a plurality of gear teeth are provided around the circumferential outer side walls of the two rotating shafts 33, and the gear teeth may be one or may be provided around the circumferential outer side walls of the rotating shafts 33.

Further, as shown in fig. 21 and 23-34, each moving contact assembly further includes an elastic assembly, a first end of the elastic assembly is connected with the moving contact 34, and during normal opening and closing, a second end of the elastic assembly is elastically matched with the rotating shaft 33, in this process, elastic deformation can provide contact pressure and restoring force for the contact mechanism 3, so as to ensure stable use of the contact mechanism 3, when the moving contact assembly is repelled by electric force, the second end of the elastic assembly is limited on the moving contact 34 to limit the rotation of the braking contact 34 in the closing direction, so that fusion welding between the moving contacts is avoided when the moving contact 34 is turned to the closing position before the operating mechanism 2 is tripped, and then the main circuit is switched on.

Specifically, the moving contact 34 is provided with a first limiting portion 345, a second limiting portion 346 and a driving portion 347, wherein the first limiting portion 345 and the second limiting portion 346 are located at two sides of the axis of the moving contact 34 respectively, the second limiting portion 346 and the third limiting portion 331 are located at the same side of the axis of rotation of the moving contact, the driving portion 347 drives the second end of the elastic component to move so as to switch limiting points, that is, the driving portion 347 pushes the second end of the elastic component to separate from the third limiting portion 331 and then to be matched with the second limiting portion 346, preferably, the driving portion 347 is adjacent to and connected with the second limiting portion 346, so that the moving distance of the second end of the elastic component is reduced, and the stability of the matching is ensured.

In normal opening and closing, as shown in fig. 30 and 31, the first end and the second end of the elastic component are elastically limited by the first limiting portion 345 and the second limiting portion 346 respectively, the driving portion 347 is located between the second limiting portion 346 and the third limiting portion 331, and the first end and the second end of the elastic component are elastically limited by the first limiting portion 345 and the third limiting portion 331 respectively; when the moving contact assembly is repelled by the electromotive force, as shown in fig. 32-34, the driving portion 347 passes over and deviates from the third limiting portion 331, in this process, the driving portion 347 drives the second end of the elastic assembly to separate from the third limiting portion 331 and then cooperate with the second limiting portion 346, the first end of the elastic assembly is still limited by the first limiting portion 345, and the second end of the elastic assembly is limited by the second limiting portion 346 and the third limiting portion 331 together, that is, the first limiting portion 345, the second limiting portion 346 and the third limiting portion 331 are collinear, so that the moving contact 34 cannot rotate in the closing direction.

A specific construction of the first contact mechanism 3 is provided in connection with fig. 6-9, 12, 13 and 21-34.

The contact mechanism 3 comprises two moving contact assemblies which are assembled in a parallel rotating mode, the two moving contact assemblies are identical and symmetrical in structure, one moving contact assembly is connected with the connecting rod assembly 22, a connecting rod mechanism is arranged between the two moving contact assemblies of the same contact mechanism 3, and in fig. 6-9, 12 and 13, the connecting rod mechanism comprises a straight rod-shaped first connecting rod 311, and two ends of the first connecting rod 311 are hinged to the two moving contact assemblies respectively.

Specifically, as shown in fig. 21-34, each moving contact assembly includes a rotating shaft 33, a moving contact 34 and an elastic assembly, the rotating shaft 33 is cylindrical, a first connecting rod 311 is hinged between the rotating shafts 33 of the two moving contact assemblies, and in fig. 6-9, 12 and 13, the length of the first connecting rod 311 is smaller than the axis connecting line length of the two rotating shafts 33; the assembly groove 330 has been seted up at the middle part of pivot 33, assembly groove 330 is along the radial intercommunication of pivot 33, assembly groove 330 two opposite lateral walls are first spacing wall 3301 and second spacing wall 3302 respectively, the both ends of assembly groove 330 are opened respectively, an open slot that the opening grow gradually has been seted up to assembly groove 330's one end edge, this open slot is as third spacing portion 331, third spacing portion 331 is located the position that is close to first spacing wall 3301, third spacing portion 331 includes the reset surface 3311 and the tight face 3312 that support that the interval is relative, wherein the tight face 3312 is close to first spacing wall 3301 more. Of course, the third limiting portion 331 may be a limiting hole with a sufficiently large inner diameter, and two opposite sides of the limiting hole are respectively a reset surface 3311 and a abutting surface 3312.

As shown in fig. 23-34, the moving contact 34 includes a plate-shaped connection portion 341, the connection portion 341 is rotatably disposed in the mounting groove 330 along a radial direction of the mounting groove 330, opposite side walls of the connection portion 341 are respectively a first abutting surface 3411 and a second abutting surface 3412, wherein the first abutting surface 3411 faces the first limiting wall 3301, the second abutting surface 3412 faces the second limiting wall 3302, opposite ends of the connection portion 341 are respectively provided with an open slot, wherein the open slot near one end of the third limiting portion 331 in the connection portion 341 is used as the second limiting portion 346, an end of a side wall on one side of the second limiting portion 346 is used as the driving portion 347, preferably, an end face of the driving portion 347 is arc-shaped, so that the second end of the elastic component can slide over the driving portion 347, when the moving contact component is repelled, as shown in fig. 32-34, the second limiting portion 346 has at least a partial area between the corresponding abutting surface 3312 and the reset surface 3311, the second end of the elastic component can be simultaneously limited by the second limiting portion 346 and the abutting surface 3312 in a matching manner, as shown in fig. 34, one side wall of the two sides of the opening of the second limiting portion 346 is located between the reset surface 3311 and the abutting surface 3312, the other side wall is located outside the third limiting portion 331 and is deviated from the driving portion 347 together to the same side of the abutting surface 3312, the second end of the elastic component is simultaneously abutted and limited with the abutting surface 3312 and the second limiting portion 346, the first limiting portion 345, the second limiting portion 346 and the third limiting portion 331 are collinear at this time, the second end of the elastic component is prevented from being separated from the second limiting portion 346 and beyond the driving portion 347, it is required to be noted that the inner diameters of the second end of the elastic component and the inner diameters of the third limiting portion 331 away from the opening end of the second limiting portion 346 and the third limiting portion 331 are larger than or equal to the outer diameters of the second end of the elastic component, but the inner diameters of the second limiting portion 346 and the third limiting portion 331 away from the opening end can be adjusted according to actual practice, i.e. according to the relative rotation amplitude between the moving contact 34 and the rotating shaft 33. Preferably, the lowest point of the second limiting portion 346 is higher than the lowest point of the third limiting portion 331, so as to further change the deformation amount of the elastic component, which is beneficial to ensuring the stability of the elastic component in cooperation with the moving contact 34.

As shown in fig. 21, 24-34, an open slot at one end of the connecting portion 341 away from the third limiting portion 331 is used as the first limiting portion 345, one end of the connecting portion 341 away from the third limiting portion 331 extends outwards to form a contact arm 342, the contact arm 342 extends along a direction deviating from a connecting line between the first limiting portion 345 and the third limiting portion 331, a movable contact 343 is arranged at one end of the contact arm 342 away from the connecting portion 341, and the movable contact 343 and the first limiting portion 345 correspond to the same side of the contact arm 342.

As shown in fig. 21, 24-34, the elastic assembly includes a contact spring 35 and a spring link 36, one end of the contact spring 35 is connected with the moving contact 34 as a first end of the elastic assembly, that is, connected with a first limit portion 345, the other end of the contact spring 35 is connected with a spring link 36, and a second end of the spring link 36 as the elastic assembly is respectively engaged with a second limit portion 346 and a third limit portion, in this embodiment, the axial movement of the spring link 36 may be limited by the moving contact 34 engaged with the rotating shaft 33.

As shown in fig. 23 and 24, the contact spring 35 preferably includes at least one tension spring 351, a torsion portion of the tension spring 351 is disposed along one side of the moving contact 34, one end of the tension spring 351 is bent outwards to form a first elastic arm 352, the first elastic arm 352 may abut against the first limiting portion 345, the other end of the tension spring 351 is bent outwards to form a hook portion 353, and the hook portion 353 is connected with the spring link 36. In this embodiment, as shown in fig. 24, the contact spring 35 includes two tension springs 351 arranged side by side, a spacing interval 350 for the moving contact 34 to pass through is left between the two tension springs 351, so that each tension spring 351 is correspondingly arranged at one side of the moving contact 34, the first elastic arms 352 of the two tension springs 351 are connected and span the moving contact 34, at this time, the two first elastic arms 352 serve as the first ends of the elastic components, and the two ends of the spring connecting rod 36 respectively pass through the two hook portions 353, thereby ensuring the connection stability of the elastic components and the moving contact 34.

As shown in fig. 26, as another embodiment of the elastic assembly, the elastic assembly includes a contact spring 35 and a spring link 36, the contact spring 35 includes two tension springs, a torsion portion of each tension spring is disposed along one side of the moving contact 34, two ends of each tension spring are respectively extended and bent outwards to form a hook portion, the spring link 36 includes a first sub-rod 361 and a second sub-rod 362, one hook portion of the two tension springs is commonly connected to the first sub-rod 361, the first sub-rod 361 forms a first end of the elastic assembly after connecting the two tension springs, the first sub-rod 361 is connected to the moving contact 34, the first sub-rod 361 can be elastically abutted in the first limiting portion 345, the first limiting portion 345 can also be a through hole for the first sub-rod 361 to pass through, the other hook portions of the two tension springs are commonly connected to the second sub-rod 362, the second sub-rod 362 forms a second end of the elastic assembly after connecting the two tension springs, and the second sub-rod 362 cooperates with the third limiting portion.

The matching process of the rotating shaft 33, the moving contact 34 and the elastic component is as follows:

when the contact mechanism 3 is normally opened and closed, the first end and the second end of the elastic component are respectively matched with the first limiting part 345 and the third limiting part 331, the elastic component deforms to provide a reset force or contact pressure for the moving contact component, when a large current flows through the main circuit, the moving contact component is repelled by electric force, the first end of the elastic component is still connected with the first limiting part 345, the second end of the elastic component moves into the second limiting part 346 and is limited into the second limiting part 346, and at the moment, the first limiting part 345, the second limiting part 346 and the third limiting part 331 are collinear, so that the moving contact 34 cannot rotate towards the closing direction, and reclosing before the operating mechanism 2 is tripped is avoided.

As shown in fig. 30-34, during normal opening and closing, the rotating shaft 33 drives the moving contact 34 to perform opening and closing rotation, and during the opening and closing state, as shown in fig. 30,

the first abutting surface 3411 abuts against the first limiting wall 3301, and the moving contact 34 is balanced under the gravity, the elasticity of the elastic component and the supporting force provided by the first limiting wall 3301; in the first half process of the closing rotation of the moving contact 34, no relative rotation occurs between the moving contact 34 and the rotating shaft 33, the first abutting surface 3411 always abuts against the first limiting wall 3301, after the two moving contacts 34 abut against each other, the rotating shaft 33 continues to rotate, at this time, the two moving contacts 34 keep in contact and cannot rotate, the first abutting surface 3411 is separated from the first limiting wall 3301, at this time, the moving contact 34 is balanced by gravity, the elastic force of the elastic component and the counter force of the other moving contact 34 (or the fixed contact), and in the opening and closing rotation process, the first end and the second end of the elastic component are respectively matched with the first limiting part 345 and the second limiting part 346. In addition, in the closing state (see fig. 31), a gap exists between the first abutment surface 3411 and the first limiting wall 3301, so as to provide an overrun and ensure the contact pressure when the contact mechanism 3 closes.

Drawing and pattern

When a large current flows through the main circuit, when the rotating shaft 33 is not rotating in the opening direction, the moving contact 34 rotates in the opening direction (in fig. 8, the left moving contact assembly rotates in the clockwise direction, the right moving contact assembly rotates in the counterclockwise direction), at this time, the second abutting surface 3412 approaches or abuts against the second limiting wall 3302, the first limiting surface is far away from the first limiting wall 3301, and at the same time, the driving portion 347 abuts against the second end of the elastic assembly, that is, the driving portion 347 abuts against the spring link 36, so that the second end of the elastic assembly is separated from the third limiting portion 331 (see fig. 32), and when the driving portion 347 passes over the third limiting portion 331 (see fig. 33) with continued rotation of the moving contact 34, the second end of the elastic assembly gradually falls into the second limiting portion 346, and the elastic assembly is deformed and is limited by the abutting of the second limiting portion 346 because the bottom of the second limiting portion 346 is higher than the bottom of the third limiting portion 331;

after the electromotive force decreases, as shown in fig. 34, the moving contact 34 tends to fall back due to its own weight, that is, rotates in the closing direction, and at this time, the second end of the elastic component is limited by the side wall (the side wall near the left side in fig. 34) of the second limiting portion 346 opposite to the abutting surface 3312, and the bottom surface of the groove of the second limiting portion 346, and the elastic component provides a counter moment balanced with the gravity for the moving contact 34, so that the second end of the elastic component cannot pass through the driving portion 347 before the operating mechanism 2 is tripped, thereby avoiding the falling of the moving contact 34 due to the decrease of the electric repulsive force.

When the operating mechanism 2 is tripped, the operating mechanism 2 drives the rotating shaft 33 to rotate in the opening direction, the moving contact 34 is blocked by the structure arranged in the housing 1 and cannot rotate continuously, and the second end of the elastic component is pushed by the reset surface 3311 of the second limiting portion 346 to pass through the driving portion 347 and fall into the third limiting portion 331 again.

Further, the moving contact assembly further includes a contact support 37, the moving contact 34 is disposed on the rotating shaft 33 through the contact support 37, in fig. 24, the moving contact support 37 is a U-shaped frame, the moving contact 34 passes through the middle of the contact support 37, preferably, as shown in fig. 25, an opening groove is disposed on two side walls of the U-shaped frame, which are close to one side of the first limiting portion 345, the two side walls extend outwards to form a mounting surface, the contact support 37 is fixed with the rotating shaft 33 through a screw, the moving contact 34 and the opening groove of the contact support 37 are coaxially assembled through an assembling shaft 39, the action of the elastic component of the hand of the moving contact 34 abuts against the opening groove, and is rotatably assembled in the assembling groove 330 of the rotating shaft 33.

A specific construction of the second contact mechanism 3 is provided in connection with fig. 10, 14-16, 21-34.

The contact mechanism 3 comprises two moving contact assemblies assembled in a side-by-side rotating way, wherein one moving contact assembly is connected with the connecting rod assembly 22, a connecting rod mechanism is arranged between the two moving contact assemblies of the same contact mechanism 3, in fig. 14 and 15, the connecting rod mechanism comprises two second connecting rods 312, a first end of each second connecting rod 312 is hinged with one moving contact assembly respectively, and a second end of each second connecting rod 312 is hinged with one connecting shaft 314.

As shown in fig. 21-34, each moving contact assembly includes a rotating shaft 33, a moving contact 34, an elastic assembly and a contact support 37, which have the same structure as the moving contact assembly, the first ends of the two second connecting rods 312 are respectively hinged with the two rotating shafts 33, the two second connecting rods 312 in fig. 14 and 15 have the same structure, each second connecting rod 312 is a rod body with a certain radian, and the length of each second connecting rod 312 is smaller than the distance between the axes of the two rotating shafts 33 and is greater than one half of the axis of the two rotating shafts 33, so that the second ends of the two second connecting rods 312 and the connecting shaft 314 correspondingly move between the rotating shafts 33.

Further, as shown in fig. 10 and 16, the link mechanism further includes a guide 313, the guide 313 is correspondingly disposed between the two rotating shafts 33, a guide groove 3131 is formed in the middle of the guide 313, the guide groove 3131 limits the movement track of the connecting shaft 314, in fig. 10 and 16, the guide groove 3131 is a linear groove, thereby limiting the movement track of the connecting shaft 314 to be a straight line, and the central axis of the guide groove 3131 is perpendicular to the axis connecting line of the two rotating shafts 33.

Of course, the lengths of the two second links 312 may be different, and the movement track may not be a straight line, and the movement track is longer, so that the space occupied by the second links 312 and the adaptive guide 313 needs to be larger.

The detailed structure of the third contact mechanism 3 is provided in connection with the figures.

The contact mechanism 3 comprises two moving contact assemblies which are assembled in a side-by-side rotating way, wherein one moving contact assembly is connected with the connecting rod assembly 22, and the two moving contact assemblies of the same contact mechanism 3 are linked through a gear transmission mechanism which comprises two gear parts which are connected in a meshed manner.

As shown in fig. 11 and 17 to 34, each moving contact assembly includes a rotating shaft 33, a moving contact 34, an elastic member, and a contact holder 37, which are identical in structure to the first contact mechanism 3, and a gear portion is provided on the circumferential outer side wall of the rotating shaft 33, wherein the formation of the gear portion may be provided by a gear 322 or an incomplete gear 322 fixed to the rotating shaft 33 by means of an insert or screw or the like, or a plurality of teeth forming the gear portion may be provided directly on the circumferential outer side wall of the rotating shaft 33, that is, in fig. 11, 17, and 18, a plurality of teeth forming the gear portion are provided on the adjacent sides of the two rotating shafts 33, respectively, or the adjacent sides of the two rotating shafts 33 are engaged and connected by the gear portion of the incomplete gear 321, and in fig. 19, 20, the circumferential outer side walls of the two rotating shafts 33 are circumferentially provided with a gear 322, respectively.

Further, as shown in fig. 9-11, the contact mechanism 3 further includes an auxiliary contact 38, the auxiliary contact 38 is disposed between the two moving contact assemblies, when the two moving contact assemblies are driven to rotate in opposite directions, the two moving contact assemblies can respectively contact with the auxiliary contact 38 to connect the main circuit, when the two moving contact assemblies are driven to rotate in opposite directions, the two moving contact assemblies can respectively separate from the auxiliary contact 38 to disconnect the main circuit, thereby facilitating the increase of over-travel, ensuring the contact pressure of the contact mechanism 3 during contact, reducing the contact resistance, and improving the overall breaking performance and stability.

Preferably, the auxiliary contact 38 may be a conductive member (see fig. 11), one end of the auxiliary contact 38 is fixed in the housing 1, the front and back sides of the other end of the auxiliary contact 38 are respectively used for contacting with two moving contact assemblies, and only the conductive member is used as the auxiliary contact 38 to have the advantages of simple structure and low cost, of course, the front and back sides of the other end of the auxiliary contact 38 may also be provided with auxiliary contacts 381 (see fig. 9 and 10), each auxiliary contact 381 is matched with the moving contact 343 of one moving contact assembly, and the auxiliary contacts 381 are provided to make the electric erosion resistance of the same stronger.

In this embodiment, the thermo-magnetic trip mechanism 5 and the wiring assembly 6 may be of the prior art, and the thermo-magnetic trip mechanism 5 is located between one of the wiring assemblies 6 and the contact mechanism 3.

As shown in fig. 5-11, the thermo-magnetic trip mechanism 5 comprises a thermo-trip device and a magnetic trip device, the magnetic trip device comprises a magnetic yoke, an armature bracket, an armature 52 and a reset piece, the magnetic yoke is opposite to the armature 52 at intervals, one end of the armature 52 is hinged on the armature bracket, the other end of the armature 52 is matched with the traction rod 20, and the reset piece is connected between the armature bracket and the armature 52; the thermal trip comprises a bimetallic strip 51 and a connecting plate 62, one end of the connecting plate 62 is respectively connected with the fixed end and the magnetic yoke of the bimetallic strip 51, the movable end of the bimetallic strip 51 is provided with an adjusting screw, and the adjusting screw is matched with the traction rod 20.

As shown in fig. 4 to 11, the wiring assembly 6 includes a wiring terminal 61 and a connecting plate 62, the wiring terminal 61 includes a wiring frame and a wiring screw screwed to the wiring frame, the wiring frame corresponds to a wiring port provided on the housing 1 for external wiring, one end of the connecting plate 62 extends into the wiring frame, the other end is electrically connected with a moving contact assembly, in this embodiment, the connecting plate 62 also serves as the connecting plate 62 in the thermo-magnetic trip mechanism 5, that is, the bimetal 51 and the yoke are electrically connected with the connecting plate 62, and the moving contact assembly is connected with the connecting plate 62 through a flexible connection.

Preferably, the connection plate 62 and the thermo-magnetic trip mechanism 5 are located in the same assembly cavity, and in fig. 6-11, the connection plate 62 and the thermo-magnetic trip mechanism 5 are located in the first assembly cavity 101.

As shown in fig. 2, 4-11 and 35-44, the arc extinguishing system 4 is arranged in the third assembly cavity 103, the arc extinguishing system 4 comprises an arc extinguishing cavity 4a, one side of the arc extinguishing cavity 4a facing the contact mechanism 3 is provided with an opening 41, a plurality of arc extinguishing grid plates arranged at intervals are arranged in the arc extinguishing cavity 4a in a surrounding mode, wherein the plurality of arc extinguishing grid plates are divided into three grid plate groups, one grid plate group is arranged on one side of the opening 41 opposite to the opening 41 at intervals as a first grid plate group 42, the other two grid plate groups are respectively arranged along two opposite sides of the opening 41 as a second grid plate group 43, the three grid plate groups are connected to form a U-shaped structure communicated with the opening, arc extinguishing grid plates of two adjacent grid plate groups are easier to elongate an arc, the arc extinguishing effect is facilitated to be improved, the moving contact assembly extends into the arc extinguishing cavity 4a from the opening 41, more arc extinguishing plates can be arranged in the arc extinguishing cavity 4a in a contact or separation mode in an arc extinguishing area formed by surrounding the three grid plate groups, and the three grid plate groups can form a U-shaped structure in the arc extinguishing cavity 4a, the arc extinguishing cavity 4a can be more easily stretched, and the arc extinguishing effect can be further improved, and the arc extinguishing effect of the arc extinguishing mechanism is further improved.

Specifically, as shown in fig. 6-11 and 36-44, the plurality of arc-extinguishing bars in the first bar sheet group 42 are first arc-extinguishing bars, a first arc-extinguishing gap is formed between two adjacent first arc-extinguishing bars, one end of the first arc-extinguishing gap is opposite to the opening 41, the plurality of arc-extinguishing bars in the second bar sheet group 43 are second arc-extinguishing bars, a second arc-extinguishing gap is formed between two adjacent second arc-extinguishing bars, one end of the second arc-extinguishing gap is opposite to the first bar sheet group 42, preferably, the first bar sheet group 42 is provided with first arc-extinguishing grooves, each second bar sheet group 43 is provided with second arc-extinguishing grooves, the first arc-extinguishing grooves are communicated between the two second arc-extinguishing grooves, the groove lines of the first arc-extinguishing grooves are arranged along a direction parallel to the second direction, and the included angle range between the groove lines of the second arc-extinguishing grooves and the first direction is 0-30 °, so that the arc can flow in the first arc-extinguishing grooves and the second arc-extinguishing grooves.

Further, the range of the included angle between the extending direction of the first arc-extinguishing grid sheet and the first direction is 0-20 degrees, and the range of the included angle between the extending direction of the second arc-extinguishing grid sheet and the second direction is 0-30 degrees, so that the arrangement mode of the arc-extinguishing grid sheets is more flexible, and the space in the arc-extinguishing cavity 4a is fully utilized.

Preferably, a connecting grid plate 44 is arranged between two adjacent grid plate groups, the middle part of the connecting grid plate 44 is bent, so that two ends of the connecting grid plate 44 are respectively opposite to arc extinguishing grid plates of the adjacent grid plate groups at intervals, the flow of an electric arc between the two grid plate groups is facilitated, and of course, the two adjacent grid plate groups can be connected through a transition grid plate group 45.

Further, the arc extinguishing system 4 includes an arc extinguishing chamber 40 and arc extinguishing members 49 (see fig. 4 and 6-11), at least one inner shell is disposed in the outer shell 1, at least one inner shell is disposed in each third assembly cavity 103, the number of the arc extinguishing chambers 40 may be one, two or more, the inner space of each arc extinguishing chamber 40 is at least a part of the arc extinguishing chamber 4a for disposing at least one grid plate group, the arc extinguishing chambers 40 of the same arc extinguishing system 4 are assembled in one inner shell, a second avoiding groove corresponding to the opening 41 is disposed on one side of the inner shell facing the contact mechanism 3, two opposite ends of the inner shell are respectively opened and are communicated with the air exhaust ports 104 disposed on the outer shell 1, and the arc extinguishing chambers 40, the arc extinguishing grid plates and the arc striking angles 46 disposed in the arc extinguishing chambers 40 can be integrally formed through the inner shell, so that modularization is facilitated, and assembly is facilitated.

Preferably, as shown in fig. 5 to 11, the arc extinguishing system 4 further includes a guiding portion 105 disposed in the housing 1, the guiding portion 105 is disposed at least on one side of the exhaust port 104, the guiding portion 105 may be disposed separately or may be formed by an inner wall of the housing 1, in this embodiment, the exhaust ports 104 are located on opposite sides of the housing 1, the guiding portion 105 is disposed on an inner wall of the housing 1 connected between the two exhaust ports 104, and the exhaust gas exhausted from the arc extinguishing chamber 40 is guided to the exhaust port 104 by the guiding portion 105.

Further, as shown in fig. 6, a guiding inclined plane 1051 is connected between the guiding part 105 and the lowest point of each exhaust port 104, in the figure, the guiding inclined plane 1051 is formed at the position of the guiding inclined plane 1051, and the guiding inclined plane 1051 may be a section of inclined plane or a plurality of inclined planes with different inclined angles are sequentially connected, which is beneficial to introducing the electric arc into the arc extinguishing grid sheet close to the exhaust port 104, and can effectively improve the arc voltage and extinguish the electric arc.

The construction of the first arc extinguishing system 4 is provided in connection with fig. 6-11 and 36-41.

The arc extinguishing system 4 comprises an arc extinguishing chamber 40, the arc extinguishing chamber 40 comprises a pair of fixed plates which are arranged at intervals, an arc extinguishing cavity 4a with four open sides is formed between the pair of fixed plates, a plurality of arc extinguishing grid plates which are arranged at intervals are arranged between the pair of fixed plates, one side of the arc extinguishing chamber 40 along the length direction is used as an opening 41 in fig. 36-41, the openings in the other three directions are all used as exhaust holes for exhausting tail gas, a plurality of arc extinguishing grid plates are arranged in the arc extinguishing cavity 4a in a surrounding manner, a U-shaped structure opposite to the opening 41 is formed, preferably, the U-shaped structure surrounded by the arc extinguishing grid plates forms a symmetrical structure about the central axis of the opening 41, the arc extinguishing grid plates are divided into a first grid plate group 42 and two second grid plate groups 43, the first grid plate group 42 is opposite to the opening 41 at intervals, the two second grid plate groups 43 are respectively arranged along two opposite sides of the opening 41, the two moving contact assemblies extend into the arc extinguishing cavity 4a from the opening 41, and the two moving contact assemblies are in a surrounding or separating area formed by the first grid plate group 42 and the two second grid groups 43.

The plurality of arc-extinguishing bars of the first bar sheet group 42 are first arc-extinguishing bars, the plurality of first arc-extinguishing bars are arranged along the second direction, a first arc-extinguishing gap is formed between two adjacent first arc-extinguishing bars, one end of each first arc-extinguishing gap is opposite to the opening 41, the exhaust hole opposite to the opening 41 is communicated with the other end of each first arc-extinguishing gap, the range of an included angle between the extending direction of each first arc-extinguishing bar sheet and the first direction is 0-20 degrees, a first arc-extinguishing notch is formed at one end of each first arc-extinguishing bar sheet, all the first arc-extinguishing notches are communicated to form a first arc-extinguishing groove, the groove line of each first arc-extinguishing groove is parallel to the second direction and is opposite to the opening 41, as shown in fig. 39 and 40, the extending direction of each first arc-extinguishing bar sheet is parallel to the first direction, two adjacent first arc-extinguishing bars are arranged at equal intervals, as shown in fig. 6-11, 38 and 41, the extending direction of one or more first arc-extinguishing bars in the middle position in the first bar sheet group 42 is parallel to the first direction, and the extending direction of the first arc-extinguishing bar sheet is symmetrical to the first direction and forms an included angle structure about the first arc-extinguishing bar group 41.

The plurality of arc-extinguishing bars of the second bar sheet group 43 are second arc-extinguishing bars, the plurality of second arc-extinguishing bars are arranged along the first direction or are arranged along the direction of an included angle with the first direction, each second arc-extinguishing bar sheet is arranged along the second direction or is arranged along the direction of an included angle with the second direction, so that two second bar sheet groups 43 and one first bar sheet group 42 form a U-shaped structure around, a second arc-extinguishing gap is formed between two adjacent second arc-extinguishing bar sheets, one end of each second arc-extinguishing gap faces the first bar sheet group 42, the exhaust hole adjacent to the opening 41 is communicated with the other end of the second arc-extinguishing gap, the included angle range between the extending direction of each second arc-extinguishing bar sheet and the second direction is 0-30 DEG, the second arc extinguishing gap has been seted up to the one end of every second arc extinguishing bars piece, all second arc extinguishing gaps intercommunication forms the second arc extinguishing groove, the both ends of first arc extinguishing groove correspond the intercommunication with the one end of two second arc extinguishing grooves respectively, as shown in fig. 39, the extending direction of second arc extinguishing bars piece all sets up along being on a parallel with the second direction, adjacent two equidistant settings of second arc extinguishing bars piece, as shown in fig. 6-11, 40 and 41, the extending direction of second arc extinguishing bars piece sets up along being the direction of contained angle with the second direction, and the one end of every second arc extinguishing bars piece inclines towards the direction of first bars piece group 42, can be equidistant setting between the adjacent two second arc extinguishing bars piece, also can be radial setting.

Further, a connection grating 44 is disposed between the first grating group 42 and the second grating group 43, so that an arc flows between the two grating groups along the connection grating 44, in fig. 6-11, 35, 37 and 39-41, the middle of the connection grating 44 is bent, so that two ends of the connection grating 44 are respectively opposite to adjacent arc-extinguishing grating sheets at intervals, preferably, the interval between one end of the connection grating 44 and the first arc-extinguishing grating sheet is similar to the first arc-extinguishing gap, the interval between the other end of the connection grating 44 and the second arc-extinguishing grating sheet is similar to the second arc-extinguishing gap, the connection grating 44 is provided with a linking groove, the preferred linking groove comprises a first linking area and a second linking area, wherein the first linking area is correspondingly communicated with one end of the first arc-extinguishing groove, and the second linking area is correspondingly linked with one end of the second arc-extinguishing groove, so that the corresponding communication of the first arc-extinguishing groove and the second arc-extinguishing groove is ensured, and the arc flow between the grating groups is facilitated.

Of course, the first gate sheet group 42 and the second gate sheet group 43 may further include a transition gate sheet group 45, where the transition gate sheet group 45 includes a plurality of transition gate sheets disposed at intervals, preferably, the transition gate sheets disposed at the side positions of the transition gate sheet group 45 are spaced from the arc-extinguishing gate sheets disposed at the side positions of the adjacent gate sheet groups, where the transition gate sheet group 45 is disposed at two sides of the first gate sheet group 42, respectively, and the plurality of transition gate sheets of each transition gate sheet group 45 are arranged at intervals along the second direction, and the transition gate sheet group 45 is provided with a communication transition arc-extinguishing slot, where the transition arc-extinguishing slot is communicated between the first arc-extinguishing slot and the second arc-extinguishing slot.

As shown in fig. 35 and 36, the arc extinguishing chamber 40 further includes a pair of gas generating members 48, where the gas generating members 48 are disposed at opposite sides in the opening 41 at intervals, each gas generating member 48 is provided with a plurality of slots, and each arc extinguishing gate is correspondingly inserted into one slot, so that the gate leg portions at two sides of the arc extinguishing gap in each arc extinguishing gate are wrapped in the gas generating member 48, and it can also be understood that the gas generating members 48 are respectively disposed at opposite sides of the arc extinguishing slot; the gas generating members 48 are provided with mounting grooves 481 at the open ends 41 correspondingly, the arc striking corners 46 are arranged in the mounting grooves 481 for striking arcs, in fig. 35 and 36, each gas generating member 48 is provided with a pair of mounting grooves 481, the pair of mounting grooves 481 of the same gas generating member 48 are arranged on two opposite sides of the open ends 41 in the second direction, the two mounting grooves 481 of the two gas generating members 48 on the same side of the open ends 41 are opposite to each other at intervals in the third direction, a pair of arc striking corners 46 are respectively assembled in the mounting grooves 481, one end of each arc striking corner 46 extends to one side of the open ends 41, and the other end is connected with a grid plate group adjacent to one side of the open ends 41, namely, the other end is opposite to an adjacent second arc extinguishing grid plate. Of course, the number of gas generating members 48 in the arc extinguishing chamber 40 can also be set according to the number of grid sets and actual requirements.

Further, the arc extinguishing system 4 further includes at least one pair of magnets 47 spaced apart from the arc extinguishing chamber 4a, each magnet 47 covers the outside of the arc extinguishing chamber 4a between one side of the opening 41 and the adjacent grid group, and a magnetic field for pushing the arc to move is formed between the opening 41 and the adjacent grid group, and in this embodiment, the magnets 47 may be fixedly disposed in the housing 1.

Preferably, the arc extinguishing system 4 further includes a guiding portion 105, the guiding portion 105 is formed by the housing 1, in fig. 1 and 6-11, at least one pair of exhaust ports 104 are respectively opened at opposite sides of the housing 1, each pair of exhaust ports 104 are opposite to each other at intervals in the second direction, the arc extinguishing chamber 40 is disposed between at least one pair of exhaust ports 104, the guiding portion 105 is formed by inner side walls of the housing 1 between the pair of exhaust ports 104, in fig. 6-11, the guiding portion 105 is formed by a bottom wall of the housing 1, a protruding height of the guiding portion 105 changes along with a distance from the exhaust ports 104, the guiding portion 105 is an arc surface with a middle portion being high and two sides being low, and the protruding height at a position closest to the exhaust ports 104 is adjusted to be favorable for being connected with the exhaust ports 104, so that exhaust gas discharged from the arc extinguishing chamber 40 is guided to the exhaust ports 104.

In this embodiment, each exhaust port 104 is also covered with at least one arc suppressing member 49, and the arc suppressing member 49 may be one or more metal mesh plates arranged in a stacked manner.

It should be noted that, when the contact mechanism 3 further includes the auxiliary contact 38, on the basis of the above-described structure, an assembling position is provided for the auxiliary contact 38, as shown in fig. 9, 10 and 42, an assembling gap 42a for assembling the auxiliary contact 38 is reserved in the first grid sheet group 42, a central axis of the assembling gap 42a is collinear with a central axis of the opening 41, the assembling gap 42a is formed by a space between two adjacent first arc extinguishing grid sheets, the space of the assembling gap 42a is larger than that of the first arc extinguishing gaps, one end of the auxiliary contact 38 is fixed in the housing 1, and the other end extends from the assembling gap 42a to the arc extinguishing chamber 4a to be matched with two moving contact assemblies.

A second configuration of the arc extinguishing system 4 is provided in connection with fig. 42.

The arc extinguishing system 4 includes two arc extinguishing chambers 40 arranged side by side, each arc extinguishing chamber 40 includes a pair of fixed plates arranged at intervals, each arc extinguishing chamber 40 forms a structure with four open sides, the inside of the two arc extinguishing chambers 40 is communicated to form an arc extinguishing chamber 4a, one side of the two arc extinguishing chambers 40 which is open in the same direction is used as an opening 41 of the arc extinguishing chamber 4a, a group of second grating pieces 43 is arranged in each arc extinguishing chamber 40, the first grating piece group 42 is divided into two sub-grating pieces 421, each sub-grating piece 421 is correspondingly assembled in one arc extinguishing chamber 40, a connecting grating piece 44 is arranged between each sub-grating piece 421 and one second grating piece group 43 or a transition grating piece group 45 is connected, in this embodiment, a plurality of first arc extinguishing pieces in the first grating piece group 42, a plurality of second grating pieces in the second grating piece group 43, the connecting grating piece 44 and the transition grating piece group 45 can be seen specifically in the structure of the first system 4.

In addition, the gas generating member 48, the arc striking angle 46, the magnet 47, the flow guiding portion 105, and the arc extinguishing member 49 may be provided in combination, the structure of which is referred to as the structure of the first arc extinguishing system 4.

When the contact mechanism 3 further includes the auxiliary contact 38, an assembly gap 42a for assembling the auxiliary contact 38 is reserved in the first grid plate group 42, the assembly gap 42a is located between the two arc extinguishing chambers 40 and the two split grid plate groups 421, a central axis of the assembly gap 42a is collinear with a central axis of the opening 41, the assembly gap 42a is formed by a space between two adjacent first arc extinguishing grid plates, the space between the assembly gap 42a is larger than that between the first arc extinguishing gaps, one end of the auxiliary contact 38 is fixed in the housing 1, and the other end extends from the assembly gap 42a to the arc extinguishing chamber 4a to be matched with the two moving contact assemblies.

A third configuration of the arc extinguishing system 4 is provided in connection with fig. 43, 44.

The arc extinguishing system 4 comprises three arc extinguishing chambers 40 arranged side by side, each arc extinguishing chamber 40 comprises a pair of fixing plates arranged at intervals, each arc extinguishing chamber 40 forms a structure with four open sides, the inner parts of the three arc extinguishing chambers 40 are communicated to form an arc extinguishing chamber 4a, one side of the three arc extinguishing chambers 40, which is open in the same direction, serves as an opening 41 of the arc extinguishing chamber 4a, a grid plate group is arranged in each arc extinguishing chamber 40, a first grid plate group 42 is arranged in the arc extinguishing chamber 40 at the middle position, two second grid plate groups 43 are respectively arranged in the arc extinguishing chambers 40 at the two sides, a connecting grid plate 44 or a transition grid plate group 45 is arranged between the first grid plate group 42 and the second grid plate group 43, and in the embodiment, a plurality of first arc extinguishing plates in the first grid plate group 42, a plurality of second arc extinguishing plates in the second grid plate group 43, the connecting grid plate 44 and the transition grid plate group 45 can be seen in detail in the structure of the first arc extinguishing system 4.

It should be noted that when the contact mechanism 3 further includes the auxiliary contact 38, the auxiliary contact 38 is provided with an assembly position, see the assembly gap 42a in the first arc extinguishing system 4.

In this embodiment, the casing 1 is an assembled structure, as shown in fig. 1-4, the casing 1 includes a base 1a, a first supporting plate 1b, a second supporting plate 1c and a cover 1d assembled in the first direction in sequence, where the cover 1d and the second supporting plate 1c are spaced relatively to form a first assembled cavity 101, the operating mechanism 2 and the traction rod 20 are rotatably disposed in the first assembled cavity 101, in fig. 3 and 4, two ends of the second supporting plate 1c and a space is left between the two ends and the cover, the space is used as a wiring cavity disposed at two ends of the first assembled cavity 101, for setting a wiring assembly 6, the wiring cavity is correspondingly provided with a wiring hole and an operating hole, where the operating hole is adjacent to the wiring hole and is disposed at a position where the cover 1d is close to an end, a driving hole is disposed in a middle portion of the cover 1d, a linkage groove is disposed in a middle portion of the cover 1d, an operating member 21 connected to the operating mechanism 2 extends from the driving hole to outside the casing 1, a linkage groove is disposed in a middle portion of the second supporting plate 1c, a linkage groove 22 of the operating mechanism 2 passes through the groove and is connected with the contact mechanism 3, a connection plate 62 of the wiring assembly 6 is disposed between the connection plate 62 and a magnetic trip mechanism 5 and a connection plate 62 of the magnetic trip mechanism 5, and a connection plate 62 is disposed between the connection plate 5 and a connection plate 5 is disposed between the connection plate 5 and a magnetic trip mechanism 5 and a connection plate 5.

The second supporting plate 1c and the first supporting plate 1b are opposite to each other at intervals to form a second assembling cavity 102, the connecting plate 62 can be positioned in the first assembling cavity 101 or the second assembling cavity 102, and the thermomagnetic tripping mechanism 5 can be assembled in the first assembling cavity 101 or jointly arranged in the first assembling cavity 101 and the second assembling cavity 102 along the first direction; the contact mechanism 3 is arranged in the second assembly cavity 102, the contact mechanism 3 and the operating mechanism 2 are respectively arranged in two different assembly cavities which are arranged in a stacked mode, a modularized structure is formed, assembly is convenient, two moving contact assemblies are respectively connected with the connecting plate 62 through flexible connection, a blocking portion 1c1 is arranged on one side, facing the contact mechanism 3, of the second supporting plate 1c, the blocking portion 1c1 separates the two moving contact assemblies of the contact mechanism 3 and is used for being matched with and limiting the swing height of the moving contact assemblies in the first direction, and the blocking portion 1c1 can be independently and fixedly arranged on the second supporting plate 1c or integrally formed by the second supporting plate 1 c. In addition, when the guide member 313 is disposed between the two contact mechanisms 3, the blocking portion 1c1 may also be used to fix the guide member 313, and of course, the guide member 313 may also be fixedly connected to other positions in the second assembly chamber 102; each moving contact assembly is connected with one connecting plate 62 through flexible connection, one moving contact assembly is in driving connection with the connecting rod assembly 22 penetrating through the linkage hole, the middle part of the first supporting plate 1b is provided with a first avoiding groove 1b1, and the moving contact assembly penetrates through the first avoiding groove 1b1 to perform opening and closing rotation in a third assembly cavity 103 formed by matching the base 1a with the first supporting plate 1 b.

Preferably, at least one inner shell is disposed in the third assembly cavity 103, all the arc extinguishing chambers 40 of one arc extinguishing system 4 are disposed in the inner shell, a second avoidance groove is formed in one side of the inner shell facing the first support plate 1b, the second avoidance groove is correspondingly communicated with the first avoidance groove 1b1 formed in the first support plate 1b and the opening 41 of the arc extinguishing cavity 4a, two moving contact assemblies of the contact mechanism 3 can extend into the arc extinguishing cavity 4a, two ends of the inner shell are opened and correspond to the exhaust ports 104 formed in the side wall of the base 1a, each exhaust port 104 is covered with an arc extinguishing member 49, in addition, the edge of the first avoidance groove 1b1 can enable the limiting moving contact 34 to rotate in the opening direction when the moving contact assemblies are repelled by electric force, namely, after the operating mechanism 2 is tripped, the rotating shaft 33 is driven to rotate in the opening direction, the moving contact 34 can not be continuously rotated by the edge of the first avoidance groove 1b1, and the flow guiding part 105 is formed by protruding from one side of the base 1a facing the first support plate 1 b. In addition, magnets 47 that cooperate with the arc extinguishing chamber 4a may be provided on the first support plate 1b, and two magnets 47 are provided at intervals opposite in the second direction and corresponding to opposite sides of the first escape groove 1b 1.

In addition, a partition board 1a1 may be disposed in the second assembly chamber 102 and the third assembly chamber 103, the partition board 1a1 dividing the space of the second assembly chamber 102 and the third assembly chamber 103 along the third direction for assembling the contact mechanism 3 and the arc extinguishing system 4 of different conductive systems, and as shown in fig. 5, the partition board 1a1 is disposed in the base 1a, and the arc extinguishing systems 4 of two adjacent conductive systems are separated by the partition board 1a 1.

It should be noted that, in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer", and the like indicate an orientation or a positional relationship based on that shown in the drawings or an orientation or a positional relationship conventionally put in use, and are merely for convenience of description, and do not indicate that the apparatus or element to be referred to must have a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating relative importance.

The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.

Claims

1. The circuit breaker comprises a shell (1), wherein an operating mechanism (2) and at least one conductive system are arranged in the shell (1), a traction rod (20) is rotatably assembled on one side of the operating mechanism (2), each conductive system comprises a contact mechanism (3), an arc extinguishing system (4) and a thermomagnetic tripping mechanism (5), the contact mechanism (3) of at least one conductive system is in driving connection with the operating mechanism (2), an operating piece (21) connected with the operating mechanism (2) extends out of the shell (1),

The method is characterized in that: operating device (2), contact mechanism (3) and arc extinguishing system (4) set up in proper order the layering in shell (1), contact mechanism (3) are including two moving contact assemblies that rotate the assembly, are rotated in opposite directions and are contacted or are rotated the separation by operating device (2) drive two moving contact assemblies in opposite directions, and the arc that produces when breaking by arc extinguishing system (4) cooperation quenching contact mechanism (3), thermomagnetic tripping device (5) set up in shell (1) between arc extinguishing system (4) and operating piece (21), are in order to trigger operating device (2) tripping by thermomagnetic tripping device (5) drive traction lever (20).

2. The circuit breaker according to claim 1, characterized in that: the novel thermal magnetic tripping device is characterized in that the interior of the shell (1) is sequentially divided into a first assembling cavity (101), a second assembling cavity (102) and a third assembling cavity (103), an operating mechanism (2) and a traction rod (20) are arranged in the first assembling cavity (101) in a rotating mode, an arc extinguishing system (4) is arranged in the third assembling cavity (103), and a thermal magnetic tripping mechanism (5) is arranged in the first assembling cavity (101) or is arranged in the second assembling cavity (102) and extends into the first assembling cavity (101).

3. The circuit breaker according to claim 2, characterized in that: one end of each movable contact assembly is rotatably connected to the joint of the first assembly cavity (101) and the second assembly cavity (102), and the other end of each movable contact assembly extends from the second assembly cavity (102) to the third assembly cavity (103) and rotates in the arc extinguishing cavity (4 a) of the arc extinguishing system (4).

4. A circuit breaker according to claim 3, characterized in that: the connection part of the first assembly cavity (101) and the second assembly cavity (102) is provided with a blocking part (1 c 1), and the blocking part (1 c 1) is positioned between the two moving contact assemblies and used for limiting the moving contact assemblies.

5. The circuit breaker according to claim 1, characterized in that: the contact mechanism (3) further comprises an auxiliary contact (38), the auxiliary contact (38) is fixedly arranged between two moving contact assemblies, and each moving contact assembly is respectively contacted with or separated from one side of the auxiliary contact (38).

6. The circuit breaker of claim 5, wherein: one end of the auxiliary contact (38) is fixedly connected with the shell (1), and the other end of the auxiliary contact (38) penetrates through the middle part of the arc extinguishing system (4) to be matched with the two moving contact assemblies respectively.

7. The circuit breaker according to claim 1, characterized in that: the two moving contact assemblies are connected through a connecting rod mechanism, and the connecting rod mechanism at least comprises one connecting rod hinged between the two moving contact assemblies.

8. The circuit breaker according to claim 1, characterized in that: the two moving contact assemblies are connected through a gear transmission mechanism, and the gear transmission mechanism at least comprises two gear parts which are in meshed connection.

9. The circuit breaker according to claim 1, characterized in that: the arc extinguishing system (4) comprises an arc extinguishing chamber (40), an opening (41) of the arc extinguishing chamber (40) faces the contact mechanism (3), the moving contact assembly extends into an arc extinguishing cavity (4 a) of the arc extinguishing chamber (40) from the opening (41), and a plurality of arc extinguishing grid plates used for arc extinguishing are arranged in the arc extinguishing cavity (4 a).

10. The circuit breaker according to claim 9, characterized in that: the arc extinguishing bars are arranged along the inner side of the arc extinguishing cavity (4 a) in a surrounding mode, the arc extinguishing bars are divided into a first bar sheet group (42) and two second bar sheet groups (43), the first bar sheet group (42) is opposite to the opening (41) in interval, and the two second bar sheets (43) are respectively arranged on two opposite sides of the opening (41).