Circuit breaker with good arc extinguishing effect

Abstract

The utility model relates to the technical field of low-voltage circuit breakers, and discloses a circuit breaker with a good arc extinguishing effect, which comprises an arc extinguishing grid plate, a moving contact and a static contact, the two sides of the arc extinguishing grid plate are fixedly connected with fixed plates, the upper ends of the fixed plates are fixedly connected with a top plate, the two sides of the lower end of the top plate are fixedly connected with side plates, and the side plates are fixedly connected with the moving contact and the static contact. One side of the side plate is fixedly connected with a fixing pipe, and a sliding plate is arranged in the fixing pipe in a sliding mode. According to the utility model, the repulsive force between the electromagnet and the permanent magnet plate drives the sliding plug to compress the cavity in the fixed pipe, so that gas is discharged through the gas blowing pipe to form gas flow, the arc extinguishing reliability of the circuit breaker is improved in cooperation with the arc extinguishing chamber, and the movable plug compresses the cavity of the fixed pipe again through the cooperation of the clamping mechanism and the tension spring. The arc blowing action time is prolonged while the volume of the cavity is not increased, and meanwhile, the reverse flow of airflow is prevented by using the reverse blowing prevention plate, so that the arc extinguishing reliability is further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of low-voltage circuit breakers, in particular to a circuit breaker with good arc extinguishing effect. Background Art

[0002] A circuit breaker is an electrical component used to control the on and off of a circuit. A circuit breaker for low voltage usually includes a housing. When the circuit to which the low voltage circuit breaker is connected is short-circuited, the free end of the moving contact in the housing of the low voltage circuit breaker is rapidly lifted by the driving component, thereby disconnecting from the static contact to disconnect the circuit and protect the electrical components in the circuit. In this process, the disconnection of the moving contact and the static contact will form an arc, which is guided into the arc extinguishing chamber through the arc-starting plates at both ends, and the hot gas generating component is used to form a gas blow to accelerate the arc into the arc extinguishing chamber. The arc extinguishing chamber is usually composed of a fixed plate and an arc extinguishing grid plate installed thereon and spaced apart. The arc extinguishing grid plate divides the arc entering the arc extinguishing chamber into several small arcs, accelerating the extinction of the arc. When the circuit is repaired, the control driving component is reset to re-fit the free end of the moving contact with the static contact to complete the circuit connection.

[0003] However, traditional low-voltage circuit breakers use hot gas generating components to generate high-temperature gas that flows from high-pressure areas to low-pressure areas, which easily forms an airflow in the opposite direction to the arc extinguishing grid, resulting in limited gas arc blowing effect, affecting the final arc extinguishing effect of the hot gas generating component and the arc extinguishing chamber combination. Utility Model Content

[0004] In view of the shortcomings of the existing low-voltage circuit breakers mentioned in the background technology during use, the utility model provides a circuit breaker with good arc extinguishing effect, which has the advantages of long air blowing time, prevention of backblowing, and good combined arc extinguishing effect, solving the technical problems raised in the above background technology.

[0005] The utility model provides the following technical scheme: a circuit breaker with good arc extinguishing effect, comprising an arc extinguishing grid, a moving contact and a static contact, wherein both sides of the arc extinguishing grid are fixedly connected with fixed plates, the upper end of the fixed plate is fixedly connected with a top plate, both sides of the lower end of the top plate are fixedly connected with side plates, one side of the side plate is fixedly connected with a fixed tube, a sliding plate is slidably arranged in the fixed tube, a lifting rod is fixedly connected at the midpoint of the upper end surface of the sliding plate, a sliding plug is slidably arranged in the fixed tube, a clamping mechanism is fixedly connected to one side of the upper end surface of the sliding plug, and a No. 1 connecting hole is provided on the rear side of the fixed tube close to the upper end.

[0006] An air inlet pipe is fixedly arranged at the lower end of the fixed tube, a connecting pipe is fixedly arranged at the midpoint of the rear end surface of the fixed tube, an air blowing pipe is fixedly arranged at the rear end of the connecting pipe, a connecting plate is fixedly connected to the upper end of the lifting rod, a permanent magnet plate is fixedly arranged at the midpoint of the upper end surface of the connecting plate, an electromagnet is fixedly arranged at the midpoint of the upper end surface of the top plate, two connecting rods are fixedly connected to the lower end of the connecting plate, and an anti-backblowing plate is fixedly connected to the lower end of the connecting rod.

[0007] Preferably, the permanent magnet plate is located above the electromagnet, the electromagnet is connected in series to the circuit connected to the circuit breaker, the acting force between the electromagnet and the permanent magnet plate is a repulsive force, the arc extinguishing grid plates are provided in a plurality and are arranged at intervals, the fixed plate is fixedly installed in the housing of the circuit breaker, the number of the fixed tubes is set to two, the upper end of the clamping mechanism is clamped and connected to the sliding plate, the air blowing tubes are provided in a plurality and the number corresponds to the number of intervals of the arc extinguishing grid plates, and the lifting rod body is slidably connected to the fixed tube.

[0008] Preferably, a top block is fixedly provided on the upper end of the inner wall of the fixed tube, the number and position of the top blocks correspond to the sliding block, the clamping mechanism includes a connecting block, the lower end of the connecting block is fixedly connected to the sliding plug, the connecting block is slidably connected to the sliding plate, a clamping groove is opened at the midpoint of the upper end of the connecting block, and a sliding block is slidably provided in the clamping groove.

[0009] The sliding block is located at the upper end of the sliding plate, and the front and rear ends of the upper end of the connecting block are both provided with limiting grooves, and the limiting block is slidably arranged in the limiting groove. The limiting block is fixedly connected to the sliding block, and the upper end of the sliding block is arranged as an inclined surface. The number of the sliding blocks is set to two, and a spring is fixedly connected between the two sliding blocks.

[0010] Preferably, an air inlet hole is provided at the lower end of the anti-backblowing plate, an air blowing hole is provided at the rear end of the anti-backblowing plate, the air inlet hole is connected with the air blowing hole, the number of the air blowing holes is set to be several, the anti-backblowing plate is slidably connected with the fixed tube, a No. 2 connecting hole is provided on one side of the lower end of the fixed tube, the air inlet hole is connected with the No. 2 connecting hole when the anti-backblowing plate slides to the top end, a tension spring is fixedly connected to the lower end of the sliding plug, the tension of the tension spring is less than the repulsive force between the electromagnet and the permanent magnet plate, and a one-way valve is fixedly provided on the air inlet pipe body.

[0011] Preferably, a lower arc-striking piece is fixedly connected to the lower end of the fixed plate, the lower end of the lower arc-striking piece is fixedly connected to the static contact near the front end, and an upper arc-striking piece is fixedly provided near the upper end of the fixed plate.

[0012] The utility model has the following beneficial effects:

[0013] 1. The utility model uses the repulsive force between the electromagnet and the permanent magnet plate as the driving force. When the circuit is short-circuited, the sliding plate drives the sliding plug to compress the upper cavity of the fixed tube through the clamping mechanism, so that the gas in the upper cavity is discharged through the air blowing pipe to form an airflow. A plurality of air blowing pipes are arranged at intervals and are flush with the intervals between the arc extinguishing grid plates, thereby improving the efficiency of arc blowing. The air blowing pipes are connected to the upper cavity by a connecting pipe. During the compression of the upper cavity, the plurality of air blowing pipes always generate airflow, thereby ensuring the stability of arc blowing. After the sliding plate slides to the maximum position, it is separated from the sliding plug, so that the sliding plug continues to compress the lower cavity under the tension of the tension spring, so that the gas in the lower cavity of the two fixed tubes is discharged from the connected air blowing holes together to form an airflow, thereby improving the effect of airflow arc blowing, and prolonging the arc blowing time while not changing the volume of the fixed tube.

[0014] 2. The utility model provides a baffle when the arc blowing structure is actuated by the cooperation of the top plate, the side plate, the fixed tube and the anti-backblowing plate, thereby preventing the high-temperature backblowing airflow that may be formed from acting on other electrical components in the circuit breaker and affecting the reliability of the circuit breaking and arc extinguishing of the circuit breaker. In addition, the anti-backblowing plate is separately arranged from the moving contact, which will not increase the mass of the moving contact and affect the speed of disconnection between the moving contact and the static contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0016] Figure 2 It is a partial structural schematic diagram of the utility model;

[0017] Figure 3 For this utility model Figure 1 Schematic diagram of the air blowing structure in FIG.

[0018] Figure 4 For this utility model Figure 3 Schematic diagram of some structures in ;

[0019] Figure 5 For this utility model Figure 4 A half-section schematic diagram of some structures in FIG.

[0020] Figure 6 For this utility model Figure 5 Schematic diagram of the structure of the card connection mechanism.

[0021] In the figure: 1. fixed plate; 2. arc extinguishing grid plate; 3. top plate; 4. side plate; 5. clamping mechanism; 501. connecting block; 502. clamping slide groove; 503. limit groove; 504. sliding block; 505. limit block; 506. spring; 6. moving contact; 7. static contact; 8. upper arc-starting plate; 9. lower arc-starting plate; 10. electromagnet; 11. lifting rod; 12. connecting plate; 13. permanent magnet plate; 14. connecting rod; 15. fixed pipe; 16. connecting pipe; 17. air blowing pipe; 18. air inlet hole; 19. air blowing hole; 20. No. 1 connecting hole; 21. sliding plate; 22. sliding plug; 23. top block; 24. air inlet pipe; 25. one-way valve; 26. No. 2 connecting hole; 27. tension spring; 28. anti-blowback plate. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] See also Figure 1 and Figure 2 A circuit breaker with good arc extinguishing effect includes an arc extinguishing grid plate 2, a moving contact 6 and a stationary contact 7. Both sides of the arc extinguishing grid plate 2 are fixedly connected with a fixed plate 1. The arc extinguishing grid plates 2 are provided in plurality. The plurality of arc extinguishing grid plates 2 are arranged at intervals to form an arc extinguishing chamber with the fixed plate 1. The fixed plate 1 is fixedly installed in the housing of the circuit breaker. A lower arc-striking piece 9 is fixedly connected to the lower end of the fixed plate 1. The lower end of the lower arc-striking piece 9 is fixedly connected to the stationary contact 7 at the front end. An upper arc-striking piece 8 is fixedly provided at the upper end of the fixed plate 1. One end of the moving contact 6 can only rotate, and the other end of the moving contact 6 is a free end.

[0024] When the circuit breaker is in normal working condition, the switch of the circuit breaker is turned on, and the contact 6 is driven to rotate through the driving mechanism inside the circuit breaker, so that the free end of the moving contact 6 is in contact with the upper end of the static contact 7. When the circuit connected to the circuit breaker is short-circuited, the driving mechanism is activated to disconnect the free end of the moving contact 6 from the static contact 7. The arc generated during the disconnection process is introduced into the arc extinguishing chamber by the upper arc-starting piece 8 and the lower arc-starting piece 9. Several arc-extinguishing grids 2 divide the arc into several small arcs to accelerate the extinction of the arc.

[0025] See also Figure 1 , Figure 3-Figure 5A top plate 3 is fixedly connected to the upper end of the fixed plate 1, and side plates 4 are fixedly connected to both sides of the lower end of the top plate 3. A fixed tube 15 is fixedly connected to one side of the side plate 4. The number of fixed tubes 15 is set to two. A sliding plate 21 is slidably arranged in the fixed tube 15, and a lifting rod 11 is fixedly connected at the midpoint of the upper end surface of the sliding plate 21. A sliding plug 22 is slidably arranged in the fixed tube 15, and a clamping mechanism 5 is fixedly connected to one side of the upper end surface of the sliding plug 22. The upper end of the clamping mechanism 5 is clamped and connected to the sliding plate 21, and a No. 1 connecting hole 20 is opened on the rear side of the fixed tube 15 near the upper end.

[0026] An air inlet pipe 24 is fixedly provided at the lower end of the fixed tube 15, a connecting pipe 16 is fixedly provided at the midpoint of the rear end surface of the fixed tube 15, an air blowing pipe 17 is fixedly provided at the rear end of the connecting pipe 16, the upper cavity of the fixed tube 15 is connected with the air blowing pipe 17 through the No. 1 connecting hole 20 and the connecting pipe 16, a plurality of air blowing pipes 17 are provided and the number corresponds to the number of intervals of the arc extinguishing grid plate 2, the air blowing pipes 17 are horizontal, and are inclined from the connecting pipe 16 toward the interval of the arc extinguishing grid plate 2, and are used to guide the airflow to the position of the small arc separated when the air blows out the arc, so as to ensure the effect of the airflow on the arc, the combination between the side plate 4, the top plate 3 and the fixed tube 15, and the fixed plate 1 are matched to block the two sides and the upper end of the air blowing pipe 17, which is conducive to reducing the loss of airflow from the sides.

[0027] The rod body of the lifting rod 11 is slidably connected to the fixed tube 15, and the sliding plug 22 divides the cavity in the fixed tube 15 into an upper cavity and a lower cavity. The lifting and lowering of the lifting rod 11 drives the sliding plate 21 to slide in the fixed tube 15, and the sliding plate 21 drives the sliding plug 22 to slide up and down through the clamping mechanism 5. When the sliding plug 22 compresses the gas in the upper cavity, the gas is discharged from the gas blowing pipe 17 through the No. 1 connecting hole 20 and the connecting tube 16, and the arc blowing effect of the generated airflow is utilized to accelerate the extinction of the arc entering the arc extinguishing chamber.

[0028] See also Figure 5 and Figure 6The sliding plate 21 drives the sliding plug 22 to slide up and down through the clamping mechanism 5. The specific process is as follows: the lower end of the connecting block 501 is fixedly connected to the sliding plug 22, the connecting block 501 is slidably connected to the sliding plate 21, a clamping groove 502 is provided at the midpoint of the upper end of the connecting block 501, the clamping groove 502 divides the middle part of the upper end of the connecting block 501 into a T-shape, a sliding block 504 is slidably provided in the clamping groove 502, the sliding block 504 is located at the upper end of the sliding plate 21, and the sliding block 504 partially extends out of the connecting block 501. When the connecting block 501 is in contact with the sliding plate 21, the lower end of the sliding block 504 abuts against the sliding plate 21 to limit the sliding of the sliding plate 21 relative to the connecting block 501, thereby driving the sliding plug 22 to move upward. The front and rear ends of the upper end of the connecting block 501 are both provided with limiting grooves 503, and a limiting block 505 is slidably arranged in the limiting groove 503. The limiting block 505 is fixedly connected to the sliding block 504, and the limiting block 505 cooperates with the limiting groove 503 to limit the sliding range of the sliding block 504 to prevent the sliding block 504 from detaching from the connecting block 501.

[0029] The upper end of the sliding block 504 is set as an inclined surface, the number of sliding blocks 504 is set to two, a spring 506 is fixedly connected between the two sliding blocks 504, and the spring 506 keeps the sliding block 504 in an extended state. The upper end of the inner wall of the fixed tube 15 is fixedly provided with a top block 23, and the number and position of the top block 23 correspond to the sliding block 504. When the sliding plate 21 slides up to the top, the lower end of the top block 23 abuts against the inclined surface of the sliding block 504, pushing the sliding block 504 to retract, so that the lower end of the sliding block 504 is removed from the sliding plate The restriction of 21 is used for the sliding plate 21 to be disconnected from the clamping mechanism 5 and the sliding plug 22. When reconnecting, the hole wall at the embedding position of the connecting block 501 at the lower end of the sliding plate 21 acts in unison with the top block 23, and the sliding block 504 is retracted by abutting. After the sliding plate 21 and the sliding plug 22 are fitted, the sliding block 504 is extended to complete the connection, so that when the clamping mechanism 5 slides to the top end on the sliding plate 21, the sliding plate 21 and the sliding plug 22 can be separated, and when the sliding plate 21 slides to the bottom end, the sliding plate 21 and the sliding plug 22 are re-clamped.

[0030] See also Figure 3 A connecting plate 12 is fixedly connected to the upper end of the lifting rod 11, and a permanent magnet plate 13 is fixedly arranged at the midpoint of the upper end surface of the connecting plate 12. An electromagnet 10 is fixedly arranged at the midpoint of the upper end surface of the top plate 3, and the permanent magnet plate 13 is located above the electromagnet 10. The electromagnet 10 is connected in series to the circuit connected to the circuit breaker. The acting force between the electromagnet 10 and the permanent magnet plate 13 is a repulsive force. When a short circuit occurs in the circuit, the magnetic force of the electromagnet 10 increases, and the connecting plate 12 is driven upward by the magnetic force, and the connecting plate 12 drives the lifting rod 11 to slide.

[0031] See also Figure 1 , Figure 3-Figure 5The lower end of the connecting plate 12 is fixedly connected to two connecting rods 14, and the lower end of the connecting rod 14 is fixedly connected to an anti-backblowing plate 28, and the lower end of the anti-backblowing plate 28 is provided with an air inlet hole 18, and the rear end of the anti-backblowing plate 28 is provided with an air blowing hole 19, and the air inlet hole 18 is connected with the air blowing hole 19, and the number of air blowing holes 19 is set to be several, and the anti-backblowing plate 28 is slidably connected to the fixed tube 15, and a No. 2 connecting hole 26 is provided on one side of the lower end of the fixed tube 15. When the anti-backblowing plate 28 slides to the top, the air inlet hole 18 is connected with the No. 2 connecting hole 26, which is used to connect the lower cavity of the fixed tube 15 and the air blowing hole 19, and the lower end of the sliding plug 22 is fixedly connected with a tension spring 27, and the tension of the tension spring 27 is less than the repulsive force between the electromagnet 10 and the permanent magnet plate 13, and a one-way valve 25 is fixedly provided on the body of the air inlet pipe 24.

[0032] The one-way valve 25 is used to allow the gas outside the fixed tube 15 to enter the lower cavity in one direction. An avoidance groove is provided at the upper end of the anti-backblowing plate 28 to prevent the moving contact 6 above the anti-backblowing plate 28 from affecting the up and down sliding of the anti-backblowing plate 28. On the one hand, the anti-backblowing plate 28 is used to provide a baffle effect during air blowing to prevent the airflow backblowing from affecting the effect. On the other hand, after the sliding plug 22 is separated from the sliding plate 21, the tension spring 27 pulls the sliding plug 22 to compress the lower cavity, so that the gas in the lower cavity passes through the No. 2 connecting hole 26 and the air inlet hole 18 and is discharged from the air blowing hole 19 to form an airflow. The anti-backblowing plate 28 simultaneously connects the lower cavities of the two fixed tubes 15, strengthens the ejected airflow, and compresses the lower cavity after the upper cavity is compressed, thereby extending the arc blowing time of the entire mechanism and further improving the arc extinguishing effect.

[0033] The usage (working principle) of the utility model is as follows:

[0034] When a short circuit occurs in the circuit to which the circuit breaker is connected, the driving mechanism in the circuit breaker drives the moving contact 6 and the static contact 7 to disconnect. The disconnection of the moving contact 6 and the static contact 7 will generate an arc. At the same time, the current flowing through the electromagnet 10 increases, and the magnetic force increases, so that the connecting plate 12 drives the lifting rod 11 to rise, and the sliding plate 21 drives the sliding plug 22 to compress the upper cavity of the fixed tube 15. The gas outside the fixed tube 15 enters the lower cavity through the air inlet pipe 24 and the one-way valve 25. The gas in the upper cavity is discharged through the air blowing pipe 17 to form an airflow, which blows the arc gas and accelerates the arc to pass through the upper inlet pipe 24. The arc sheet 8 and the lower arc-starting sheet 9 enter the arc extinguishing chamber, and cooperate with the arc extinguishing grid plate 2 arranged at intervals in the arc extinguishing chamber to accelerate the extinction of the arc. During the arc blowing process, the top plate 3, the side plate 4, the outer wall of the fixed tube 15 and the anti-backblowing plate 28 form a baffle to suppress the backblowing of the airflow. After the upper cavity is compressed, the No. 2 connecting hole 26 is connected to the air inlet hole 18, the sliding plug 22 is separated from the sliding plate 21 and compresses the lower cavity under the pull of the tension spring 27, so that the gas in the lower cavity is discharged through the connected air blowing hole 19 to form an airflow, without changing the volume of the fixed tube 15 and prolonging the arc blowing time.

[0035] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A circuit breaker with good arc extinguishing effect, comprising an arc extinguishing grid plate (2), a moving contact (6) and a stationary contact (7), wherein both sides of the arc extinguishing grid plate (2) are fixedly connected to a fixing plate (1), characterized in that: The upper end of the fixed plate (1) is fixedly connected to a top plate (3), and the lower ends of the top plate (3) are fixedly connected to side plates (4) on both sides, and one side of the side plate (4) is fixedly connected to a fixed tube (15), and a sliding plate (21) is slidably arranged in the fixed tube (15), and a lifting rod (11) is fixedly connected at the midpoint of the upper end surface of the sliding plate (21), and a sliding plug (22) is slidably arranged in the fixed tube (15), and a clamping mechanism (5) is fixedly connected to one side of the upper end surface of the sliding plug (22), and a No. 1 connecting hole (20) is provided at the upper end of the inner rear side of the fixed tube (15); An air inlet pipe (24) is fixedly arranged at the lower end of the fixed tube (15), a connecting tube (16) is fixedly arranged at the midpoint of the rear end surface of the fixed tube (15), an air blowing tube (17) is fixedly arranged at the rear end of the connecting tube (16), a connecting plate (12) is fixedly connected to the upper end of the lifting rod (11), a permanent magnet plate (13) is fixedly arranged at the midpoint of the upper end surface of the connecting plate (12), an electromagnet (10) is fixedly arranged at the midpoint of the upper end surface of the top plate (3), two connecting rods (14) are fixedly connected to the lower end of the connecting plate (12), and an anti-backblowing plate (28) is fixedly connected to the lower end of the connecting rod (14).

2. A circuit breaker with good arc extinguishing effect according to claim 1, characterized in that: The permanent magnet plate (13) is located above the electromagnet (10); the electromagnet (10) is connected in series to the circuit connected to the circuit breaker; the acting force between the electromagnet (10) and the permanent magnet plate (13) is a repulsive force; the arc extinguishing grid plates (2) are arranged in a plurality and arranged at intervals; the fixed plate (1) is fixedly installed in the housing of the circuit breaker; the number of the fixed tubes (15) is set to two; the upper end of the clamping mechanism (5) is clamped and connected to the sliding plate (21); the number of the air blowing tubes (17) is arranged in a plurality and the number corresponds to the number of intervals between the arc extinguishing grid plates (2); and the rod body of the lifting rod (11) is slidably connected to the fixed tube (15).

3. A circuit breaker with good arc extinguishing effect according to claim 1, characterized in that: A top block (23) is fixedly arranged at the upper end of the inner wall of the fixed tube (15), and the number and position of the top blocks (23) correspond to the sliding blocks (504). The clamping mechanism (5) comprises a connecting block (501), the lower end of the connecting block (501) is fixedly connected to the sliding plug (22), the connecting block (501) is slidably connected to the sliding plate (21), a clamping groove (502) is provided at the midpoint of the upper end of the connecting block (501), and a sliding block (504) is slidably arranged in the clamping groove (502); The sliding block (504) is located at the upper end of the sliding plate (21), and the front and rear ends of the upper end of the connecting block (501) are both provided with limiting grooves (503), and a limiting block (505) is slidably arranged in the limiting groove (503), and the limiting block (505) is fixedly connected to the sliding block (504), and the upper end of the sliding block (504) is arranged as an inclined surface, and the number of the sliding blocks (504) is arranged as two, and a spring (506) is fixedly connected between the two sliding blocks (504).

4. A circuit breaker with good arc extinguishing effect according to claim 1, characterized in that: An air inlet (18) is provided at the lower end of the anti-backblowing plate (28), and an air blowing hole (19) is provided at the rear end of the anti-backblowing plate (28). The air inlet (18) is connected to the air blowing hole (19), and the number of the air blowing holes (19) is set to be several. The anti-backblowing plate (28) is slidably connected to the fixed tube (15), and a second connecting hole (26) is provided on one side of the lower end of the fixed tube (15). When the anti-backblowing plate (28) slides to the top end, the air inlet (18) is connected to the second connecting hole (26). A tension spring (27) is fixedly connected to the lower end of the sliding plug (22), and the tension of the tension spring (27) is smaller than the repulsive force between the electromagnet (10) and the permanent magnet plate (13). A one-way valve (25) is fixedly provided on the body of the air inlet pipe (24).

5. A circuit breaker with good arc extinguishing effect according to claim 1, characterized in that: The lower end of the fixed plate (1) is fixedly connected to a lower arc-striking piece (9), the lower end of the lower arc-striking piece (9) is fixedly connected to the static contact (7) at the front end, and the upper end of the fixed plate (1) is fixedly provided with an upper arc-striking piece (8).

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