CN113936978A - Plastic case circuit breaker - Google Patents

Abstract

The invention relates to a molded case circuit breaker, which comprises a base, an operating mechanism, a plurality of breaking units and a pneumatic tripping device, wherein each breaking unit comprises two cover plates, two fixed contacts, a rotary double-breakpoint moving contact system and two arc extinguishing chambers, the pneumatic tripping device comprises a base, a sliding block, a connecting rod and a spring, the connecting rod is rotatably arranged on the base, the upper end of the connecting rod is arranged corresponding to the operating mechanism, the lower end of the connecting rod is abutted to the sliding block, and the sliding block slides to push the connecting rod to move to trigger unhooking. Compared with the prior art, the circuit breaker improves the safety and the sensitivity of tripping, and has compact and stable integral structure.

Description

Plastic case circuit breaker

Technical Field

The invention relates to the technical field of circuit breakers, in particular to a molded case circuit breaker.

Background

The circuit breaker is a switching device capable of closing, carrying, and opening/closing a current under a normal circuit condition and a current under an abnormal circuit condition for a predetermined time. With the continuous improvement of the performance and the function of the circuit breaker in the modern society, the existing circuit breaker can not meet the market demand, the non-modularization of the circuit breaker unit can not meet the time demand, and a new type of circuit breaker needs to be developed.

In the working process of the circuit breaker, when a short-circuit fault occurs to a certain phase, timely and rapid tripping is required, the tripping process is usually realized by triggering a tripping mechanism through an external linkage mechanism, various triggering modes exist in the prior art to drive the tripping mechanism, and the tripping is realized in a gas protection mode.

At present, the rotating double-breakpoint moving contact system of the molded case circuit breaker is one of the developing directions, the existing double-breakpoint moving contact system has many parts and a complex structure, after a contact bridge is repelled by electric repulsive force, because the electric repulsive force is reduced, the moving contact can be closed secondarily or closed for many times due to shaking under the action of spring tension, and if a clamping device cannot rapidly clamp the contact bridge at the limit position, the contact bridge can be very unfavorable for breaking.

In addition, during the breaking process of the circuit breaker, the voltage between the contacts causes air dielectric discharge to form electric arcs, so in the circuit breaker switch, an arc extinguishing chamber is usually used for arc extinguishing to ensure the safe operation of the electric appliance. However, the arc striking effect of the existing arc extinguishing chamber is not good, so that the electric arc cannot enter the arc extinguishing chamber structure more quickly, and the better arc extinguishing effect cannot be achieved.

Comprehensively, how to improve the tripping safety, sensitivity and structural stability of the molded case circuit breaker is a problem still to be solved.

Disclosure of Invention

The present invention is directed to solve the above problems and to provide a molded case circuit breaker, so as to improve the trip safety, sensitivity and structural stability of the molded case circuit breaker.

The purpose of the invention is realized by the following technical scheme:

a molded case circuit breaker comprises a base, an operating mechanism, a plurality of breaking units and a pneumatic tripping device, wherein the breaking units are installed in the base, the pneumatic tripping device is arranged between two adjacent breaking units, and the operating mechanism is arranged at the upper parts of the breaking units and the pneumatic tripping device;

the breaking unit includes:

the two cover plates form an independent box body unit, and a cavity is formed inside the box body unit;

the two static contacts are arranged in the cavity of the box body unit in a diagonal mode, and wiring terminals of the static contacts extend out of the box body unit;

the rotary double-breakpoint moving contact system is rotatably arranged in the cavity of the box body unit and is positioned between the two fixed contacts; and

the two arc extinguish chambers are arranged in the box body unit cavities at two sides of the rotary double-breakpoint moving contact system;

the pneumatic trip device includes:

the base is provided with a sliding block accommodating chamber, and the sliding block accommodating chamber is provided with a vent hole communicated with the breaking unit;

the sliding block is arranged in the sliding block accommodating cavity of the base;

the middle part of the connecting rod is rotatably arranged on the base, the upper end of the connecting rod is arranged corresponding to the traction rod of the operating mechanism, the lower end of the connecting rod is abutted against the sliding block, and the sliding block slides to push the connecting rod to move to trigger unhooking; and

and the connecting rod reset spring is arranged between the base and the connecting rod and used for resetting the connecting rod.

Preferably, the two cover plates comprise a first cover plate and a second cover plate, the first cover plate and the second cover plate are connected together through screws, a central shaft hole is formed in the middle of each of the first cover plate and the second cover plate, and two waist-shaped holes are formed in two sides of each central shaft hole;

the rotary double-breakpoint moving contact system is rotatably arranged in the box body unit cavity through a central shaft penetrating through the central shaft hole, and is provided with a sliding shaft which penetrates through the waist-shaped hole and slides in the waist-shaped hole.

Preferably, the first cover plate and the second cover plate are respectively symmetrically provided with a square sink groove, and the square sink grooves are internally provided with air outlet holes corresponding to the vent holes in the slide block accommodating chamber.

Preferably, the air outlet holes on the first cover plate and the second cover plate are asymmetrically arranged.

Preferably, three relatively independent ribs are arranged on a base of the pneumatic tripping device: muscle a, muscle b and muscle c, three muscle enclose into two independent cavitys with the base together: the cavity a and the cavity b are respectively communicated with the air outlet holes in the first cover plate and the second cover plate.

The rib a, the rib b and the rib c are arranged in parallel, one end of the rib a is provided with a connecting rib which connects the three ribs into a whole, the connecting rib and the three ribs form an E-shaped structure, and the sliding block is arranged in two openings of the E-shaped structure;

the slider be the U type form of placing horizontally, in the open end inserted E type structure, blind end top is protruding, and the protruding connecting rod motion of top promotes at the gliding in-process of slider, triggers the unhook.

Preferably, the rotary double break point moving contact system comprises:

the rotating shaft is of a flat cylindrical structure, a central shaft is arranged at the center of the rotating shaft, two arc-shaped guide grooves which are centrosymmetric relative to the central shaft are arranged in the middle of the radial side wall of the rotating shaft, and two open grooves which are centrosymmetric relative to the central shaft and two first installation positioning holes are sequentially arranged on the side of the axial end face of the rotating shaft;

the contact bridge penetrates through the arc-shaped guide grooves and is rotatably installed on the rotating shaft through the central shaft, a round hole is formed in the center of the contact bridge, the arc-shaped guide grooves are formed in two sides of the contact bridge, a movable contact is arranged at the end part of the contact bridge, and the shape of the contact bridge, the arc-shaped guide grooves and the movable contact are arranged in central symmetry relative to the center of the contact bridge;

the two spring shafts are used for installing springs and respectively and axially penetrate through the open grooves of the rotating shaft;

the two springs are respectively arranged on two end faces of the rotating shaft along the axial direction of the rotating shaft, and two ends of each spring are connected to the spring shaft; and

and the two small connecting rods axially penetrate through the first mounting positioning holes of the rotating shaft respectively, and the adjacent spring shafts are connected with the small connecting rods through connecting rods.

Preferably, the end face of the rotating shaft along the axial direction is provided with a screen plate for covering, the inner side of the screen plate is provided with a screen plate boss, the screen plate boss and the rotating shaft clamp the connecting rod in the middle, a spring containing cavity is formed between the screen plate and the end face of the rotating shaft, and the spring is located in the spring containing cavity;

the cross section of the open slot is of an arc structure, bosses are arranged at two ends of the contact bridge on one side corresponding to the movable contact, and a roller is sleeved in the middle of the spring shaft;

the small connecting rod penetrates through the connecting rod and the rotating shaft respectively and is riveted with the connecting rod and the rotating shaft together.

Preferably, the arc extinguishing chamber comprises:

the two arc isolating walls are arranged at intervals, and a plurality of slideways are arranged on the inner side edges of the arc isolating walls; and

the arc extinguishing grid pieces are embedded into the slide ways of the two arc isolating walls;

the arc-extinguishing grid pieces and the two arc-insulating walls are combined to form an arc-extinguishing chamber, and the arc-insulating walls are provided with magnetic conductive plates at one end of an opening of the arc-extinguishing chamber;

the two end parts of the contact bridge are positioned in the middle of the arc extinguishing grid plate.

Preferably, the magnetic conductive plate is arranged on the arc-isolating wall at a side edge opposite to the insertion end of the arc-extinguishing grid piece, the arc-isolating wall is provided with a groove, and the magnetic conductive plate is embedded in the groove;

the slideway is of a multi-group groove structure which is arranged on the inner wall of the arc-isolating wall in parallel, the arc-extinguishing grid pieces are sequentially inserted into the slideway at intervals in parallel, the upper part of the inner wall of the arc-isolating wall along the insertion end of the arc-extinguishing grid pieces is an open U-shaped slideway, and the lower part of the inner wall of the arc-isolating wall is an installation cavity;

the magnetic conduction plate is a strip-shaped rectangular plate, the length direction of the magnetic conduction plate is parallel to the arrangement direction of the arc extinguishing grid pieces, and the length of the magnetic conduction plate is consistent with the arrangement width of the arc extinguishing grid pieces;

the arc extinguishing bars are metal sheets provided with U-shaped arc extinguishing grooves, the U-shaped arc extinguishing grooves are formed by connecting multiple sections of arc lines, and an invaginated notch is formed in the middle of each U-shaped arc extinguishing groove.

Preferably, the fixed contact is U-shaped, a magnetic conducting rod is placed in the U-shaped groove of the fixed contact, a magnetic conducting plate is arranged on the outer side of the other end of the arc extinguish chamber opposite to the magnetic conducting rod, and the magnetic conducting rod and the magnetic conducting plate can form a closed magnetic circuit, so that the arc is more easily attracted into the arc extinguish chamber under the action of a magnetic field, and effective arc extinction is achieved. Preferably, the convex part of the base of the pneumatic tripping device is fixedly connected with the grooves of the two cover plates of the breaking unit;

preferably, the operating mechanism comprises an upper connecting rod, a lower connecting rod and a handle, wherein the lower end of the upper connecting rod is rotatably connected to the upper end of the lower connecting rod, and the lower end of the lower connecting rod is connected to the rotary double-breakpoint movable contact system.

The working principle of the circuit breaker is as follows:

when the circuit breaker is in an initial state, the moving contact makes the moving contact and the fixed contact under the combined action of the spring, the spring shaft and the small connecting rod; when the circuit breaks down, the current in the circuit can increase sharply, an electric repulsion force is generated between the moving contact and the static contact, the moving contact rotates under stress, at the moment, the spring shaft enters the arc-shaped guide groove of the contact bridge under the action of the spring and the arc-shaped groove, the arc-shaped guide groove tightly clamps the spring shaft, the function of repelling and locking the moving contact is realized, and the moving contact is effectively prevented from falling back.

Meanwhile, the static contact and the moving contact form electric arcs, the magnetic conduction plate is arranged at the bottom of the arc isolating wall of the arc extinguish chamber, the generated electric arcs are ignited, the electric arcs are lifted to the arc extinguishing grid pieces on the upper portion from the bottom, after the electric arcs are introduced into the uppermost arc extinguishing grid pieces, the arc extinguishing grid pieces uniformly cut the electric arcs, one long arc is divided into a plurality of sections of short arcs, the best arc extinguish effect is achieved, the air outlets are formed in the two sides of the arc isolating wall, the hot air generated during arc extinguishing can be timely cooled and dispersed, the arc extinguishing is accelerated through cooling, the arc extinguishing is facilitated, and the arc extinguishing effect is better.

When a circuit is in fault, the produced gas in the arc extinguish chamber enters the pneumatic tripping device, the sliding block of the pneumatic tripping device pushes the push rod under the impact of high-heat gas, the push rod is connected with the operating mechanism and pushes the traction rod of the operating mechanism, the circuit breaker finishes tripping and cuts off the circuit, and the pneumatic tripping device is provided with two sliding blocks, so that the circuit can be quickly cut off.

Compared with the prior art, the invention has the following beneficial effects:

1. the moving contact system realizes the stress transmission of the contact through the pair of springs, reduces the number of parts, has simple structure and stable contact structure, when short-circuit current generates electric repulsion force, the moving contact rotates under stress, and separation is accelerated under the action of the springs, so that the breaking capacity of a product is improved.

2. The other side of moving contact is provided with the boss, has better intensity and wearability for current structure.

3. The small connecting rod, the connecting rod and the rotor are welded together, so that the stability of the structure is improved, and the manufacturability is good.

4. The boss screen board that sets up on the screen board, boss and pivot laminating are at the both ends of connecting rod, avoid the departure of connecting rod in the motion process.

5. The planar shape of both sides of the connecting rod is different, and in the motion process, the planar surface effectively prevents the excessive rotation of the connecting rod, and is helpful for controlling the rotating position of the connecting rod.

6. The bottom of the arc-isolating wall is provided with the magnetic conducting plate, so that the length of the arc-extinguishing grid piece is shortened, the cost is reduced, the structure is simple, electric arcs can enter the arc-extinguishing chamber more quickly, after the electric arcs are introduced into the arc-extinguishing grid piece, the arc-extinguishing grid piece uniformly cuts the electric arcs, one long electric arc is divided into multiple sections of short electric arcs, the best arc-extinguishing effect is achieved, and rapid arc extinguishing is guaranteed.

7. The arc-extinguishing grid piece is installed on the arc-isolating wall, the sliding grooves are formed in the edges of the sliding grooves and the arc-extinguishing grid pieces, the installation and the disassembly are very convenient, the assembly mode is simple, the maintenance is very convenient, the arc-extinguishing grid pieces in different forms can be installed on the structure according to design requirements, and the whole arc-extinguishing chamber is flexible and changeable.

8. Be equipped with the gas outlet on the lateral wall of flash barrier, guarantee that the hot gas flow that produces can in time cool off and disperse when the arc extinguishing, and the gas outlet can cooperate with the pneumatic trip gear of circuit breaker, further promotes the breaking speed of circuit breaker.

9. Three independent ribs are arranged on the base, the shell and the sliding block form two independent closed cavities together, the two independent closed cavities integrally form a closed assembly, a cavity for installing the connecting rod and the spring is arranged on the base, all components can be independently assembled, and each cavity is provided with an air hole respectively and is used for being communicated with the air holes in the two independent shells, so that the closed cavity is communicated with the left contact working cavity and the right contact working cavity which are adjacent. When a single-phase fault occurs in the circuit, high-temperature and high-pressure gas generated in the working cavity enters the corresponding sealing cavity to push the sliding block, so that the tripping operation is further completed; when two-phase and three-phase short circuit faults exist in the circuit, high-temperature and high-pressure gas can enter the sealing cavity respectively, and the tripping operation is finished simultaneously. Because the voltage of each phase in the circuit is different, the arc voltage generated in the working cavity of each phase is also different. By adopting the design of two sealed cavities, the safety of the product is further improved. And the gas in the two cavities can simultaneously push the two sliding blocks to move left and right, so that the gas-liquid separation device is more stable and has higher sensitivity.

10. The invention adopts the slide block to push the linkage to carry out tripping operation, the slide block only moves left and right to drive the connecting rod to rotate, the top surface of the slide block is in an arc shape, the contact area between the slide block and the connecting rod is larger, the abrasion is smaller, and therefore, the stroke and the stress of the pneumatic device are controllable.

Drawings

Fig. 1 is a schematic view of the overall structure of the circuit breaker;

FIG. 2 is a schematic view of the overall structure of the breaking unit;

FIG. 3 is a schematic view of an internal structure of the breaking unit;

FIG. 4 is a schematic structural diagram of a rotary double-break moving contact system;

FIG. 5 is a schematic structural diagram of a rotating shaft of a rotary double-breakpoint moving contact system;

fig. 6 and 7 are schematic connection structural diagrams of the rotary double-breakpoint moving contact system;

FIG. 8 is a schematic structural diagram of a contact bridge of the rotary double-breakpoint moving contact system;

fig. 9 is a schematic structural diagram of a pneumatic trip device;

fig. 10 is a schematic structural view of a base of the pneumatic trip device;

FIG. 11 is a schematic diagram of the arc chute;

FIG. 12 is a schematic structural view of an arc-isolating wall of the arc-extinguishing chamber;

fig. 13 is a schematic view of a connection structure of the operating mechanism and the breaking unit;

FIG. 14 is a schematic structural view of the moving and stationary contacts in an initial contact state;

FIG. 15 is a schematic view of a structure for repelling a moving contact and a stationary contact under a large current;

fig. 16 is a schematic view of the arrangement and operation of the magnetic conducting rod and the magnetic conducting plate.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments.

Referring to fig. 1, a molded case circuit breaker includes a base 400, an operating mechanism 300, a breaking mechanism composed of three independent breaking units 100, and a pneumatic trip device 200, wherein the breaking units 100 are installed in the base 400, the pneumatic trip device 200 is disposed between two adjacent breaking units 100, and the operating mechanism 300 is disposed on the upper portions of the breaking units 100 and the pneumatic trip device 200.

As shown in fig. 2 and 3, the breaking unit 100 includes two cover plates 101, two fixed contacts 102, a rotary double-break movable contact system 103, and two arc extinguishing chambers 104. Wherein, the two cover plates 101 form an independent box body unit, and a cavity is formed inside the box body unit; the two fixed contacts 102 are diagonally arranged in the cavity of the box body unit, the wiring terminals of the fixed contacts 102 extend out of the box body unit, and the rotary double-breakpoint moving contact system 103 is rotatably arranged in the cavity of the box body unit and is positioned between the two fixed contacts 102; two arc-extinguishing chambers 104 are installed in the box unit cavities on both sides of the rotary double-breakpoint moving contact system 103.

Referring to fig. 13 and 16, the stationary contact 102 is U-shaped, a magnetic conducting rod 106 is disposed in the U-shaped groove of the stationary contact 102, a magnetic conducting plate 105 is disposed outside the other end of the arc extinguish chamber 104 opposite to the magnetic conducting rod 106, and the magnetic conducting rod 106 and the magnetic conducting plate 105 can form a closed magnetic circuit, so that the arc is more easily attracted into the arc extinguish chamber under the action of the magnetic field, thereby achieving effective arc extinction.

Specifically, the two cover plates 101 include a first cover plate and a second cover plate, the first cover plate and the second cover plate are connected together through screws, a central shaft hole 1011 is arranged in the middle of the first cover plate and the second cover plate, and two waist-shaped holes 1012 are arranged on two sides of the central shaft hole 1011; the rotary double-breakpoint moving contact system 103 is rotatably installed in the cavity of the box body unit through a central shaft penetrating through the central shaft hole 1011, the rotary double-breakpoint moving contact system 103 is installed with a sliding shaft 1013, and the sliding shaft 1013 penetrates through the waist-shaped hole 1012 and slides in the waist-shaped hole 1012. The first cover plate and the second cover plate are respectively symmetrically provided with a square sinking groove, and the square sinking grooves are internally provided with air outlet holes 1014 corresponding to the air vent holes 205 in the slide block accommodating chamber. The air outlet holes 1014 of the first cover plate and the second cover plate are arranged asymmetrically.

As shown in fig. 9 and 10, the pneumatic trip device 200 includes:

the breaking unit comprises a base 201, wherein a slide block accommodating chamber is arranged on the base 201, and is provided with a vent hole 205 communicated with the breaking unit 100;

a slider 202 disposed in the slider accommodating chamber of the base 201;

the middle part of the connecting rod 203 is rotatably arranged on the base 201, the upper end of the connecting rod 203 is arranged corresponding to the operating mechanism 300, the lower end of the connecting rod is abutted against the sliding block 202, and the sliding block 202 slides to push the connecting rod 203 to move to trigger unhooking;

and the connecting rod return spring 204 is arranged between the base 201 and the connecting rod 203 and is used for returning the connecting rod 203.

The convex part of the base 201 of the pneumatic trip device 200 is fixedly connected with the grooves of the two cover plates of the breaking unit 100.

As shown in fig. 9 and 10, the base 201 of the pneumatic trip device 200 is provided with three relatively independent ribs: rib a206, rib b207 and rib c208, the three ribs and the base 201 enclose two independent cavities: the cavity a209 and the cavity b210 are respectively provided with a slide block 202, and the cavity a and the cavity b are respectively communicated with the air outlet 1014 on the first cover plate and the second cover plate. The rib a, the rib b and the rib c are arranged in parallel, one end of the rib a is provided with a connecting rib which connects the three ribs into a whole, the connecting rib and the three ribs form an E-shaped structure, and the sliding block 202 is arranged in two openings of the E-shaped structure; the slider 202 is the U type form of placing horizontally, and in the open end inserted E type structure, the blind end top is protruding, and the protruding connecting rod 203 that promotes in the gliding in-process of slider 202 moves, triggers the unhook.

The structure of the rotary double-break moving contact system 103 is shown in fig. 4-8, and comprises:

the rotating shaft 1031 is of a flat cylindrical structure, a central shaft 10314 is arranged at the center of the rotating shaft 1031, two arc-shaped open slots 10313 which are centrosymmetric relative to the central shaft 10314 are arranged in the middle of the radial side wall of the rotating shaft 1031, and two open slots 10311 which are centrosymmetric relative to the central shaft 10314 and two first mounting positioning holes 10312 are sequentially arranged on the rotating shaft 1031 along the axial end surface side of the rotating shaft 1031;

the contact bridge 1032 penetrates through the arc-shaped open slot 10313, and is rotatably mounted on the rotating shaft 1031 through a central shaft 10314, a circular hole is formed in the center of the contact bridge 1032, arc-shaped guide grooves 10321 are formed in two sides of the contact bridge 1032, a movable contact 10322 is arranged at the end part of the contact bridge 1032, and the shape of the contact bridge 1032, the arc-shaped guide grooves 10321 and the movable contact are arranged in central symmetry relative to the center of the contact bridge 1032;

two spring shafts 1033 for mounting the springs 1034 and axially penetrating the opening grooves 10311 of the rotating shaft 1031, respectively;

two springs 1034 respectively arranged on two end faces of the rotating shaft 1031 along the axial direction thereof, and two ends of each spring 1034 are connected to the spring shaft 1033; and

two small connecting rods 1035 axially penetrate through the first mounting positioning hole 10312 of the rotating shaft 1031, and the adjacent spring shafts 1033 and the small connecting rods 1035 are connected through a connecting rod 1036.

In addition, a screen panel 1037 for covering is arranged on the end face of the rotating shaft 1031 along the axial direction, a screen panel boss 10371 is arranged on the inner side of the screen panel 1037, the connecting rod 1036 is clamped between the screen panel boss 10371 and the rotating shaft 1031, a spring accommodating cavity is formed between the screen panel 1037 and the end face of the rotating shaft 1031, and the spring is located in the spring accommodating cavity; the screen panel is installed on the rotation shaft 1031 through the second installation positioning hole 10315; the cross section of the open slot 10311 is in an arc structure, the two ends of the contact bridge 1032 are provided with a boss 10323 at one side corresponding to the movable contact 10322, and the middle of the spring shaft 1033 is sleeved with a roller 1038; the small link 1035 passes through the connecting rod and the rotating shaft 1031, respectively, and is riveted with the connecting rod and the rotating shaft 1031.

When the circuit breaker is in an initial state, as shown in fig. 14, the contact bridge makes the movable contact and the fixed contact under the combined action of the spring, the spring shaft and the small connecting rod. When a circuit breaks down, electric repulsion force can be generated between the moving contact and the static contact, the contact bridge is stressed to rotate, at the moment, the spring shaft enters the arc-shaped guide groove under the action of the spring and the arc-shaped groove, the spring shaft is tightly clamped, the moving contact is repelled to realize the locking function, so that the moving contact is effectively prevented from falling back, the tripping action is smoothly completed, and the problem that the moving contact can be closed for a second time or closed for a plurality of times due to shaking under the action of the spring tension is avoided.

As shown in fig. 11 and 12, the arc extinguishing chamber 104 includes:

the two arc isolating walls 1041 are arranged alternately, and a plurality of slideways 10412 are arranged on the inner side edge of the arc isolating walls 1041; and

a plurality of arc-extinguishing grid plates 1042 embedded in the slide rails 10412 of the two arc-isolating walls 1041;

the arc-extinguishing grid pieces 1042 and the two arc-insulating walls 1041 are combined to form an arc-extinguishing chamber, and the arc-insulating walls 1041 are provided with magnetic conductive plates 1043 at one ends of openings of the arc-extinguishing chamber; the contact bridge 1032 has two ends located in the middle of the arc chute 1042.

The magnetic conduction plate 1043 is arranged on the side edge of the arc-isolating wall 1041 opposite to the insertion end of the arc-extinguishing grid 1042, a groove is arranged on the arc-isolating wall 1041, and the magnetic conduction plate 1043 is embedded in the groove; the slideway 10412 is a multi-group of groove-shaped structures which are arranged in parallel on the inner wall of the arc-isolating wall 1041, the arc-extinguishing grid plates 1042 are inserted into the slideway 10412 in sequence at intervals, the upper part of the inner wall of the arc-isolating wall 1041 along the insertion end of the arc-extinguishing grid plate 1042 is an open U-shaped slideway 10412, and the lower part is an installation cavity; the magnetic conducting plate 1043 is a strip-shaped rectangular plate, the length direction of the magnetic conducting plate is parallel to the arrangement direction of the arc-extinguishing grid plates 1042, the length of the magnetic conducting plate 1043 is consistent with the arrangement width of the arc-extinguishing grid plates 1042, and arc-extinguishing chamber exhaust ports 10411 are arranged on the arc-extinguishing chamber partition wall 1041. The arc-extinguishing grid 1042 is a metal sheet provided with a U-shaped arc-extinguishing groove, the U-shaped arc-extinguishing groove is formed by connecting a plurality of sections of arc lines, and an invaginated notch is formed in the middle of the U-shaped arc-extinguishing groove.

The explosion chamber is through being equipped with the magnetic conductive plate on the flash barrier wall, the arc striking is carried out to the electric arc that produces, can be with electric arc from the magnetic conductive plate bottom arc extinguishing bars piece that rises to upper portion, thereby make electric arc can get into in the explosion chamber more fast, electric arc is introduced behind the arc extinguishing bars piece of the top, arc extinguishing bars piece evenly cuts electric arc, a long electric arc is cut apart into the short electric arc of multistage, reach best arc extinguishing effect, be equipped with the gas outlet on the lateral wall of flash barrier wall, guarantee that the hot gas flow that produces can in time cool off when the arc extinguishing and disperse, and the gas outlet can cooperate with the pneumatic trip gear of circuit breaker, strengthen the magnetic blow-out effect greatly.

As shown in fig. 13, the operating mechanism 300 includes an upper link 301, a lower link 302 and a handle 303, the lower end of the upper link 301 is rotatably connected to the upper end of the lower link 302, the lower end of the lower link 302 is connected to the rotary double-break point moving contact system 103, the link 203 is rotatably mounted on the base 201, the upper end of the link corresponds to the drawbar of the operating mechanism 300, and the lower end of the link is abutted against the slider 202, under abnormal conditions, the current in the circuit will increase sharply, an electrical repulsion force is generated between the moving contact and the stationary contact, the moving contact is forced to rotate, thereby forming an arc, the slider of the pneumatic trip device pushes the link 203 under the impact of high-heat gas, thereby pushing the drawbar of the operating mechanism 300, tripping the circuit breaker, and cutting off the circuit.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims (10)

1. A molded case circuit breaker comprises a base (400), an operating mechanism (300), a plurality of breaking units (100) and a pneumatic tripping device (200), wherein the breaking units (100) are installed in the base (400), the pneumatic tripping device (200) is arranged between two adjacent breaking units (100), the operating mechanism (300) is arranged at the upper parts of the breaking units (100) and the pneumatic tripping device (200),

the breaking unit (100) comprises:

the box body comprises two cover plates (101), wherein the two cover plates (101) form an independent box body unit, and a cavity is formed inside the box body unit;

the two static contacts (102) are arranged in a cavity of the box body unit in a diagonal mode, and wiring terminals of the static contacts (102) extend out of the box body unit;

a rotary double-breakpoint moving contact system (103) which is rotatably arranged in the cavity of the box body unit and is positioned between the two fixed contacts (102); and

the two arc extinguish chambers (104) are arranged in the box body unit cavities at two sides of the rotary double-breakpoint moving contact system (103);

the pneumatic trip device (200) comprises:

the breaking unit (100) is provided with a breaking unit (100), and the breaking unit (100) is provided with a sliding block accommodating chamber;

the sliding block (202) is arranged in the sliding block accommodating cavity of the base (201);

the middle part of the connecting rod (203) is rotatably arranged on the base (201), the upper end of the connecting rod (203) is arranged corresponding to a traction rod of the operating mechanism (300), the lower end of the connecting rod is abutted against the sliding block (202), and the sliding block (202) slides to push the connecting rod (203) to move to trigger unhooking; and

and the connecting rod return spring (204) is arranged between the base (201) and the connecting rod (203) and is used for returning the connecting rod (203).

2. A molded case circuit breaker according to claim 1, wherein the two cover plates (101) comprise a first cover plate and a second cover plate, the first cover plate and the second cover plate are connected together by a screw, a central shaft hole (1011) is formed in the middle of the first cover plate and the second cover plate, and two waist-shaped holes (1012) are formed on two sides of the central shaft hole (1011);

the rotary double-breakpoint moving contact system (103) is rotatably installed in the cavity of the box body unit through a central shaft penetrating through the central shaft hole (1011), the rotary double-breakpoint moving contact system (103) is provided with a sliding shaft (1013), and the sliding shaft (1013) penetrates through the waist-shaped hole (1012) and slides in the waist-shaped hole (1012).

3. The breaking unit (100) of the double-breakpoint molded case circuit breaker according to claim 2, wherein the first cover plate and the second cover plate are symmetrically provided with a square sink groove, and the square sink groove is provided with an air outlet (1014) corresponding to the vent hole (205) in the slider accommodating chamber.

4. The breaking unit (100) of the double break molded case circuit breaker according to claim 3, wherein the air outlet holes (1014) of the first and second cover plates are asymmetrically arranged.

5. The breaking unit (100) of the double-breakpoint molded case circuit breaker according to claim 4, wherein the base (201) of the pneumatic trip device (200) is provided with three relatively independent ribs: muscle a (206), muscle b (207) and muscle c (208), three muscle enclose into two independent cavitys with base (201) together: the cavity body a (209) and the cavity body b (210) are respectively provided with a sliding block (202), and the cavity body a and the cavity body b are respectively communicated with the air outlet holes (1014) on the first cover plate and the second cover plate.

6. The breaking unit (100) of the double-break moulded case circuit breaker according to any of the claims from 1 to 5, characterized in that said rotary double-break movable contact system (103) comprises:

the rotating shaft (1031) is of an oblate cylindrical structure, a central shaft is arranged at the center of the rotating shaft (1031), two arc-shaped open grooves (10313) which are centrosymmetric relative to the central shaft are formed in the middle of the radial side wall of the rotating shaft (1031), and two open grooves (10311) and two first mounting positioning holes (10312) which are centrosymmetric relative to the central shaft are sequentially formed in the rotating shaft (1031) along the axial end surface side of the rotating shaft (1031);

the contact bridge (1032) penetrates through the arc-shaped open slot (10313) and is rotatably mounted on the rotating shaft (1031) through the central shaft, a round hole is formed in the center of the contact bridge (1032), arc-shaped guide grooves (10321) are formed in two sides of the contact bridge (1032), a movable contact (10322) is arranged at the end of the contact bridge (1032), and the shape of the contact bridge (1032), the arc-shaped guide grooves (10321) and the movable contact are arranged in central symmetry relative to the center of the contact bridge (1032);

two spring shafts (1033) for mounting springs (1034) and axially penetrating into the opening grooves (10311) of the rotating shaft (1031), respectively;

the two springs (1034) are respectively arranged on two end faces of the rotating shaft (1031) along the axial direction of the rotating shaft, and two ends of each spring (1034) are connected to the spring shaft (1033); and

and the two small connecting rods (1035) are respectively and axially arranged in the first mounting positioning holes (10312) of the rotating shaft (1031) in a penetrating manner, and the adjacent spring shafts (1033) are connected with the small connecting rods (1035) through connecting rods (1036).

7. The breaking unit (100) of the double-breakpoint molded case circuit breaker according to claim 6, wherein a shroud (1037) for covering is arranged on an end surface of the rotating shaft (1031) along an axial direction of the rotating shaft, a shroud boss (10371) is arranged on an inner side of the shroud (1037), the shroud boss (10371) and the rotating shaft (1031) clamp the connecting rod (1036) in the middle, a spring accommodating cavity is formed between the shroud (1037) and the end surface of the rotating shaft (1031), and the spring is located in the spring accommodating cavity.

8. Breaking unit (100) of a double-break molded case circuit breaker according to claim 6, characterized in that the arc extinguishing chamber (104) comprises:

the two arc isolating walls (1041) are arranged at intervals, and a plurality of slideways (10412) are arranged on the inner side edge of each arc isolating wall (1041); and

the arc extinguishing grid pieces (1042) are embedded into the slide ways (10412) of the two arc isolating walls (1041);

the arc extinguishing grid plates (1042) and the two arc isolating walls (1041) are combined to form an arc extinguishing chamber, and the arc isolating walls (1041) are provided with magnetic conductive plates (1043) at one end of an opening of the arc extinguishing chamber;

the two ends of the contact bridge (1032) are positioned in the middle of the arc extinguishing grid plate (1042).

9. The breaking unit (100) of the double-breakpoint plastic case circuit breaker according to claim 8, wherein the magnetic conductive plate (1043) is disposed on a side of the arc-isolating wall (1041) opposite to the insertion end of the arc-extinguishing grid plate (1042), a groove is disposed on the arc-isolating wall (1041), and the magnetic conductive plate (1043) is embedded in the groove;

the chute (10412) is the cell type structure of multiunit parallel arrangement each other arc wall (1041) inner wall, parallel the inserting of arc extinguishing bars piece (1042) interval in proper order in the chute (10412), arc wall (1041) inner wall is followed the upper portion that arc extinguishing bars piece (1042) inserted the end is open U type chute (10412), and the lower part is the installation cavity.

10. The breaking unit (100) of the double-breakpoint molded case circuit breaker according to claim 8, wherein the fixed contact (102) is U-shaped, a magnetic conductive rod (106) is disposed in the U-shaped groove of the fixed contact (102), and a magnetic conductive sheet (105) is disposed outside the arc extinguish chamber (104) at the other end opposite to the magnetic conductive rod (106);

the convex part of the base (201) of the pneumatic tripping device (200) is fixedly connected with the grooves of the two cover plates of the breaking unit (100);

the operating mechanism (300) comprises an upper connecting rod (301), a lower connecting rod (302) and a handle (303), wherein the lower end of the upper connecting rod (301) is rotatably connected to the upper end of the lower connecting rod (302), and the lower end of the lower connecting rod (302) is connected to the rotary double-breakpoint moving contact system (103).

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