An arc extinguishing mechanism for a miniature circuit breaker

Abstract

The utility model provides a kind of arc extinguishing mechanism of miniature circuit breaker, including shell and arc extinguishing chamber, the arc extinguishing chamber is arranged in shell, for eliminating arc generated when moving contact and static contact open and close;The arc extinguishing chamber includes arc shield and several louvers, several louvers are arranged in arc shield, and several exhaust holes are opened on arc shield;Several arc leakage grooves and arc leakage passages are opened in shell, the inner cavity of arc extinguishing chamber is communicated with outside through exhaust hole, arc leakage groove and arc leakage passage.The utility model relates to arc extinguishing mechanism of miniature circuit breaker, is provided with arc shield, several exhaust holes are opened on arc shield, several arc leakage grooves and arc leakage passages are opened in shell, high-temperature high-pressure ionized gas produced by arc combustion in the inner cavity of arc extinguishing is discharged quickly after cooling and deionization through arc leakage groove and arc leakage passage, avoid damaging other components in circuit breaker, ensure the normal open and close function of circuit breaker.

Description

Technical Field

[0001] This utility model relates to the field of circuit breaker equipment technology, and in particular to an arc extinguishing mechanism for a miniature circuit breaker. Background Technology

[0002] Circuit breakers are crucial electrical components in power distribution systems. Besides connecting and disconnecting current in circuits, they also provide overload and short-circuit protection for the circuits and related equipment. When a circuit breaker interrupts a short-circuit current, a strong electric arc is generated when the moving and stationary contacts separate. This arc produces a large amount of high-temperature, high-pressure ionized gas. If this gas is not quickly cooled and expelled from the arc-extinguishing chamber, it will cause significant damage to the electrical components and the entire circuit.

[0003] Current circuit breakers primarily rely on arc-extinguishing mechanisms to extinguish the electric arc generated when interrupting short-circuit current. However, existing arc-extinguishing mechanisms have poor sealing properties. The electric arc generated during short-circuit current interruption, along with the hot gas and molten metal particles produced by the arc, can easily escape from the arc-extinguishing mechanism and enter other parts of the circuit breaker, causing component burnout or jamming, leading to the failure of the entire circuit breaker. For example, moving parts such as springs, connecting rods, and trip latches may become stuck, preventing the circuit breaker from opening and closing normally. Utility Model Content

[0004] In view of the shortcomings of the prior art described above, the technical problem to be solved by this utility model is to provide an arc extinguishing mechanism for a miniature circuit breaker, which solves the problem caused by the poor sealing performance of the arc extinguishing mechanism of the circuit breaker in the prior art.

[0005] To achieve the above objectives, this utility model provides an arc-extinguishing mechanism for a miniature circuit breaker, comprising a housing and an arc-extinguishing chamber. The arc-extinguishing chamber is disposed within the housing and is used to eliminate the electric arc generated when the moving and stationary contacts open and close. The arc-extinguishing chamber includes an arc-extinguishing cover and several grid plates, with the grid plates disposed within the arc-extinguishing cover and several vent holes provided on the arc-extinguishing cover. The housing has an arc-venting channel and several arc-venting grooves, and the inner cavity of the arc-extinguishing chamber communicates with the outside through the vent holes, arc-venting grooves, and arc-venting channel.

[0006] Preferably, the housing is provided with a left end limiting block, a right end limiting block, an upper end limiting block, and a lower end limiting block. The left end limiting block, the right end limiting block, the upper end limiting block, and the lower end limiting block abut against the outer end face of the arc extinguishing chamber, respectively, for fixing the arc extinguishing chamber in the housing.

[0007] Preferably, the arc-extinguishing cover includes a front side plate, a rear side plate, and an end connecting plate. The front side plate and the rear side plate are parallel to each other and are fixedly connected by the end connecting plate. Both the front side plate and the rear side plate are provided with a plurality of grid plate connecting holes, and the front and rear sides of the grid plates are provided with a plurality of grid plate retaining teeth. The grid plates are fixed in the arc-extinguishing cover through the grid plate connecting holes and the grid plate retaining teeth.

[0008] Preferably, the grid plate retaining teeth include a left-end retaining tooth, a middle retaining tooth, and a right-end retaining tooth; the left-end retaining tooth is provided on both the front and rear sides of the grid plate; the middle retaining tooth is provided on either the front or rear side of the grid plate; and the right-end retaining tooth is provided on the other side. The grid plate connecting holes include a left-end connecting hole, a middle connecting hole, and a right-end connecting hole. Adjacent grid plates are installed and arranged in the arc-extinguishing hood in a front-to-back opposite manner.

[0009] Preferably, the end of the grid plate away from the end connecting plate has a grid plate cavity; adjacent grid plates are arranged in opposite directions, and adjacent grid plate cavities are staggered.

[0010] Preferably, the end connecting plate includes a front bent portion, a middle connecting portion, and a rear bent portion, and the three are integrally connected; the end of the front bent portion away from the middle connecting portion is fixedly connected to the front side plate, and the end of the rear bent portion away from the middle connecting portion is fixedly connected to the rear side plate; the vent is opened on the front bent portion, the rear bent portion, the front side plate, and the rear side plate.

[0011] Preferably, the end of the grid near the end connecting plate is adapted to the shape of the end connecting plate.

[0012] Preferably, the housing further includes a moving contact, a stationary contact, an arc-starting plate, a coil, and a magnetic yoke. The magnetic yoke is disposed above the arc-extinguishing chamber, and the coil is disposed within the magnetic yoke. The stationary contact includes a stationary contact welding portion, a stationary contact bending portion, and a stationary contact magnetically conductive portion. The stationary contact welding portion is fixedly connected to the coil, and the stationary contact magnetically conductive portion is disposed between the magnetic yoke and the top surface of the arc-extinguishing chamber. The contact point on the stationary contact bending portion abuts against the moving contact. One end of the arc-starting plate is disposed below the arc-extinguishing chamber, and the other end extends to the outer periphery of the moving contact.

[0013] Preferably, the housing includes a base and a top cover, which are fastened and fixedly connected; the base is provided with an upper yoke stop block, a lower yoke stop block, and a lower stop block for the magnetic conductive part of the stationary contact, the bottom surface of the yoke is disposed between the upper yoke stop block and the lower yoke stop block, and the magnetic conductive part of the stationary contact is disposed between the lower yoke stop block and the lower stop block for the magnetic conductive part of the stationary contact.

[0014] As described above, the arc-extinguishing mechanism of the miniature circuit breaker involved in this utility model has the following beneficial effects:

[0015] 1. The arc-extinguishing mechanism of the miniature circuit breaker involved in this utility model has several grid plates arranged in the arc-extinguishing chamber. When an electric arc is generated between the stationary contact and the moving contact, the electric arc is introduced into the arc-extinguishing chamber. The several grid plates divide the electric arc into many short arcs connected in series. Each short arc forms a near-cathode region near the grid plate. At the instant the alternating current crosses zero, a dielectric recovery strength is rapidly established in the near-cathode region. In addition, the grid plates themselves have good heat dissipation properties and can quickly absorb the heat of the electric arc, accelerating the cooling and deionization of the electric arc. Therefore, under the conditions of strong dielectric recovery strength, low temperature and sufficient deionization, the electric arc cannot reignite after the current crosses zero, thus achieving reliable extinguishing.

[0016] 2. The arc extinguishing mechanism of the miniature circuit breaker involved in this utility model is provided with an arc extinguishing cover, which has several exhaust holes. The housing has an arc venting channel and several arc venting grooves. The arc extinguishing mechanism allows the high-temperature and high-pressure ionized gas generated by the electric arc combustion in the inner cavity to be quickly discharged through the arc venting grooves and arc venting channel after cooling and deionization, so as to avoid damage to other components in the circuit breaker and ensure the normal opening and closing function of the circuit breaker.

[0017] 3. The arc extinguishing mechanism of the miniature circuit breaker involved in this utility model has a grid plate cavity at the end of the grid plate, and the grid plates are arranged in the arc extinguishing chamber in an alternating manner with opposite front and back sides. In this way, the arc is elongated between adjacent grid plates, which can extinguish the arc more quickly. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the spatial structure of the arc-extinguishing chamber of the arc-extinguishing mechanism of the miniature circuit breaker involved in this utility model;

[0019] Figure 2 This is a schematic diagram of the spatial structure of the arc-extinguishing cover of the arc-extinguishing mechanism of the miniature circuit breaker involved in this utility model;

[0020] Figure 3 This is a schematic diagram of the spatial structure of the grid plates of the arc-extinguishing mechanism of the miniature circuit breaker involved in this utility model;

[0021] Figure 4 This is an internal structural diagram of the base of the arc-extinguishing mechanism of the miniature circuit breaker involved in this utility model;

[0022] Figure 5 yes Figure 4 The front view;

[0023] Figure 6 This is a schematic diagram of the spatial structure of the housing of the arc-extinguishing mechanism of the miniature circuit breaker involved in this utility model.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1. Grid plate; 11. Left end retaining tooth; 12. Middle retaining tooth; 13. Right end retaining tooth; 14. Grid plate cavity;

[0026] 2. Arc extinguishing cover; 20. Rear side plate vent; 21. Front side plate; 22. Rear side plate; 23. End connecting plate; 230. Front bend; 231. Middle connecting part; 232. Rear bend; 24. Left end connecting hole; 25. Middle connecting hole; 26. Right end connecting hole; 27. Front side plate vent; 28. Front bend vent; 29. ​​Rear bend vent;

[0027] 3. Housing; 30. Upper stop block of the magnetic yoke; 31. Base; 310. Arc venting channel; 32. Top cover; 33. Lower end limiting block; 34. Left end limiting block; 35. Right end limiting block; 36. Lower stop block of the magnetic conductive part of the stationary contact; 37. Lower stop block of the magnetic yoke; 38. Base guide plate; 380. Top cover guide plate; 39. Arc venting groove;

[0028] 4. Moving contact; 5. Coil; 6. Magnetic yoke; 7. Stationary contact; 71. Magnetic conductive part of stationary contact; 72. Bending part of stationary contact; 73. Welding part of stationary contact; 8. Arc-starting plate; 9. Terminal block. Detailed Implementation

[0029] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.

[0030] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of this invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of this invention, should still fall within the scope of the technical content disclosed herein. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0031] This utility model discloses an arc-extinguishing mechanism for a miniature circuit breaker. For ease of description, the length direction of the housing 3 is defined as the left-right direction, the width direction as the front-back direction, and the height direction as the up-down direction. Figure 5 In the diagram, the left and right directions of the paper are left and right respectively, the top and bottom directions of the paper are top and bottom respectively, and the front and back directions of the paper are front and back respectively.

[0032] like Figures 1-6 As shown, this utility model provides an arc-extinguishing mechanism for a miniature circuit breaker, including a housing 3 and an arc-extinguishing chamber. The arc-extinguishing chamber is disposed in the housing 3 and is used to eliminate the electric arc generated when the moving contact 4 and the stationary contact 7 are opened and closed. The arc-extinguishing chamber includes an arc-extinguishing cover 2 and several grid plates 1. The several grid plates 1 are disposed in the arc-extinguishing cover 2, and the arc-extinguishing cover 2 is provided with several vent holes. The housing 3 is provided with an arc-venting channel 310 and several arc-venting grooves 39. The inner cavity of the arc-extinguishing chamber is connected to the outside through the vent holes, the arc-venting grooves 39, and the arc-venting channel 310.

[0033] The arc-extinguishing mechanism of the miniature circuit breaker involved in this utility model is used to eliminate the electric arc generated when the moving contact 4 and the stationary contact 7 are opened and closed. The high-temperature and high-pressure ionized gas generated by the electric arc combustion enters the arc-venting groove 39 through the exhaust hole after cooling and deionization, and then is quickly discharged through the arc-venting channel 310 to avoid damage to other components in the circuit breaker and ensure the normal opening and closing function of the circuit breaker.

[0034] Preferred, such as Figure 6 As shown, the housing 3 is provided with a left end limiting block 34, a right end limiting block 35, an upper end limiting block, and a lower end limiting block 33. The left end limiting block 34, the right end limiting block 35, the upper end limiting block, and the lower end limiting block 33 respectively abut against the outer end face of the arc extinguishing cover 2 to fix the arc extinguishing chamber in the housing 3.

[0035] Preferred, such as Figures 1-3 As shown, the arc-extinguishing cover 2 includes a front side plate 21, a rear side plate 22, and an end connecting plate 23. The front side plate 21 and the rear side plate 22 are parallel to each other and are fixedly connected by the end connecting plate 23. Several grid plate connecting holes are provided on both the front side plate 21 and the rear side plate 22. Several grid plate retaining teeth are provided on the front and rear sides of the grid plate 1. The grid plate 1 is fixed in the arc-extinguishing cover 2 through the grid plate connecting holes and the grid plate retaining teeth.

[0036] Preferred, such as Figure 2 , Figure 3 As shown, the grid plate retaining teeth include a left-end retaining tooth 11, a middle retaining tooth 12, and a right-end retaining tooth 13. The left-end retaining tooth 11 is provided on both the front and rear sides of the grid plate 1, the middle retaining tooth 12 is provided on one side of the front and rear sides of the grid plate 1, and the right-end retaining tooth 13 is provided on the other side. The grid plate connecting holes include a left-end connecting hole 24, a middle connecting hole 25, and a right-end connecting hole 26. Adjacent grid plates 1 are installed and arranged in the arc-extinguishing cover 2 in a front-to-back opposite manner.

[0037] Preferred, such as Figure 3 , Figure 4As shown, a grid cavity 14 is formed at the right end of the grid plate 1; adjacent grid plates 1 are arranged in opposite directions, and adjacent grid cavities 14 are staggered. The grid cavity 14 is U-shaped or V-shaped; in this embodiment, the grid cavity 14 is V-shaped. The purpose of staggering adjacent grid cavities 14 is to lengthen the arc in the arc-extinguishing chamber, so that the arc can be extinguished more quickly.

[0038] In this embodiment, as Figures 1-3 As shown, the middle retaining tooth 12 is disposed on the front side of the grid plate 1, and the right retaining tooth 13 is disposed on the rear side of the grid plate 1. That is, if the left retaining tooth 11 on the front side of a certain grid plate 1 is installed into the left connecting hole 24 of the front side plate 21, the middle retaining tooth 12 on the front side is installed into the middle connecting hole 25 of the front side plate 21; the left retaining tooth 11 on the rear side is installed into the left connecting hole 24 of the rear side plate 22, and the right retaining tooth 13 on the rear side is installed into the right connecting hole 26 of the rear side plate 22; then the left retaining tooth 11 on the front side of the adjacent grid plate 1 is installed into the left connecting hole 24 of the rear side plate 22, the middle retaining tooth 12 on the front side is installed into the middle connecting hole 25 of the rear side plate 22, the left retaining tooth 11 on the rear side is installed into the left connecting hole 24 of the front side plate 21, and the right retaining tooth 13 on the rear side is installed into the right connecting hole 26 of the front side plate 21. Thus, by installing adjacent grid plates 1 in opposite directions, the grid plate cavities 14 are staggered.

[0039] Preferred, such as Figure 2 As shown, the end connecting plate 23 includes a front bent portion 230, a middle connecting portion 231, and a rear bent portion 232, and the three are connected as a whole; the front end of the front bent portion 230 is fixedly connected to the front side plate 21, and the rear end of the rear bent portion 232 is fixedly connected to the rear side plate 22; the exhaust holes are opened on the front bent portion 230, the rear bent portion 232, the front side plate 21, and the rear side plate 22.

[0040] Furthermore, in this embodiment, the front bend 230 and the rear bend 232 are arranged symmetrically about the centerline of the intermediate connecting portion 231. The vents are further divided into front bend vent 28, rear bend vent 29, front side plate vent 27, and rear side plate vent 20, depending on their location.

[0041] Preferred, such as Figure 3 As shown, the left end of the grid plate 1 is adapted to the shape of the end connecting plate 23.

[0042] Preferred, such as Figure 4 , Figure 5As shown, the housing 3 also includes a moving contact 4, a stationary contact 7, an arc-starting plate 8, a coil 5, and a magnetic yoke 6. The magnetic yoke 6 is located on the upper side of the arc-extinguishing chamber, and the coil 5 is located in the magnetic yoke 6. The stationary contact 7 includes a stationary contact welding part 73, a stationary contact bending part 72, and a stationary contact magnetic conductive part 71. The stationary contact welding part 73 is welded and fixedly connected to the coil 5, and the stationary contact magnetic conductive part 71 is located between the magnetic yoke 6 and the top surface of the arc-extinguishing chamber. The contact point on the stationary contact bending part 72 abuts against the moving contact 4. One end of the arc-starting plate 8 is located on the lower side of the arc-extinguishing chamber, and the other end extends to the outer periphery of the moving contact 4.

[0043] Preferred, such as Figure 6 As shown, the housing 3 includes a base 31 and a top cover 32, which are fastened and fixedly connected. The base 31 is provided with an upper yoke stop 30, a lower yoke stop 37, and a lower stop 36 for the magnetic conductive part of the stationary contact. The bottom surface of the magnetic yoke 6 is located between the upper yoke stop 30 and the lower yoke stop 37, and the magnetic conductive part 71 of the stationary contact is located between the lower yoke stop 37 and the lower stop 36.

[0044] In this embodiment, arc-extinguishing grooves 39 are respectively formed on the inner sidewalls of the base 31 and the upper cover 32, and the positions of the arc-extinguishing grooves 39 are aligned with the positions of the exhaust holes 27 on the front side plate and the exhaust holes 20 on the rear side plate. The left end limiting block 34, right end limiting block 35, upper end limiting block, and lower end limiting block 33 are symmetrically arranged on the inner sidewalls of the base 31 and the upper cover 32, cooperating to achieve the positioning of the arc-extinguishing chamber. The shapes of the left end limiting block 34, right end limiting block 35, upper end limiting block, and lower end limiting block 33 match the shape of the arc-extinguishing cover 2. For example, the end face of the left end limiting block 34 that abuts against the end connecting plate 23 is set as a slope, etc., which will not be repeated here. The upper end limiting block can be the same block as the lower stop block 36 of the stationary contact magnetic guide section, or different blocks can be used.

[0045] Preferred, such as Figure 6 As shown, a base guide plate 38 is provided on the inner wall of the base 31, and an upper cover guide plate 380 is provided on the inner wall of the upper cover 32. The upper cover guide plate 380 and the base guide plate 38 cooperate with each other to form an arc venting channel 310 in the housing 3, which is used to discharge the gas generated by the electric arc combustion to the outside of the circuit breaker.

[0046] The arc-extinguishing mechanism of the miniature circuit breaker involved in this utility model works on the following principle:

[0047] First, according to the appendix Figures 1-6 Based on the descriptions of the aforementioned components, each component is manufactured and assembled. The moving contact 4 is connected to the external circuit via terminal 9, and the coil 5 is also connected to the external circuit via terminal 9. When the moving contact 4 and the stationary contact 7 are in contact, the circuit is connected.

[0048] When the circuit is closed or opened, there is a gap between the moving contact 4 and the stationary contact 7. Due to the presence of current, the current breaks down the gap between the moving contact 4 and the stationary contact 7 to generate an electric arc plasma. The current in the coil 5 generates a magnetic field, which is transmitted through the magnetic yoke 6 and the magnetic conductive part 71 of the stationary contact. According to the principles of electromagnetism, the arc plasma is subjected to the Lorentz force in the magnetic field. The arc plasma at the moving contact 4 enters the arc-extinguishing chamber from the lower part through the arc-initiating plate 8, and the arc plasma at the stationary contact 7 enters the arc-extinguishing chamber from the upper part through the stationary contact bending part 72. That is, the arc between the moving contact 4 and the stationary contact 7 is forcibly pulled into the arc-extinguishing chamber by the Lorentz force. The arc in the arc-extinguishing chamber is divided into multiple short arcs in series by several grid plates 1. Under the action of the near-cathode effect, the arc is extinguished. At the same time, the grid plates 1 made of metal material rapidly absorb the arc heat, accelerating the cooling and deionization of the arc. The gas in the arc-extinguishing chamber is discharged from the shell 3 through the exhaust port, the arc-venting groove 39, and the arc-venting channel 310.

[0049] The arc-extinguishing mechanism of this utility model relates to a miniature circuit breaker. An arc-extinguishing cover 2 is disposed on the outer periphery of several grid plates 1. These grid plates 1 are arranged in an alternating, reversed pattern within the arc-extinguishing cover 2. This elongates the arc between adjacent grid plates 1, allowing the arc to extinguish more quickly. The arc-extinguishing cover 2 has several vent holes, and the inner wall of the housing 3 has arc-venting grooves 39 and arc-venting channels 310. These allow the high-temperature, high-pressure ionized gas generated by the arc combustion to be cooled and deionized before being discharged to the outside of the housing 3, preventing damage to other components of the circuit breaker and ensuring the normal opening and closing functions of the circuit breaker.

[0050] In summary, this utility model effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0051] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. An arc-extinguishing mechanism for a miniature circuit breaker, characterized in that: The device includes a housing (3) and an arc-extinguishing chamber. The arc-extinguishing chamber is disposed in the housing (3) and is used to eliminate the electric arc generated when the moving contact (4) and the stationary contact (7) are opened and closed. The arc-extinguishing chamber includes an arc-extinguishing cover (2) and several grid plates (1). The several grid plates (1) are disposed in the arc-extinguishing cover (2), and several exhaust holes are provided on the arc-extinguishing cover (2). An arc-venting channel (310) and several arc-venting grooves (39) are provided in the housing (3). The inner cavity of the arc-extinguishing chamber is connected to the outside through the exhaust holes, the arc-venting grooves (39) and the arc-venting channel (310).

2. The arc-extinguishing mechanism of the miniature circuit breaker according to claim 1, characterized in that: The housing (3) is provided with a left end limiting block (34), a right end limiting block (35), an upper end limiting block, and a lower end limiting block (33). The left end limiting block (34), the right end limiting block (35), the upper end limiting block, and the lower end limiting block (33) respectively abut against the outer end face of the arc extinguishing cover (2) to fix the arc extinguishing chamber in the housing (3).

3. The arc-extinguishing mechanism of the miniature circuit breaker according to claim 1, characterized in that: The arc-extinguishing cover (2) includes a front side plate (21), a rear side plate (22), and an end connecting plate (23). The front side plate (21) and the rear side plate (22) are parallel to each other and are fixedly connected by the end connecting plate (23). The front side plate (21) and the rear side plate (22) are each provided with a number of grid plate connecting holes. The front side and the rear side of the grid plate (1) are each provided with a number of grid plate retaining teeth. The grid plate (1) is fixed in the arc-extinguishing cover (2) through the grid plate connecting holes and the grid plate retaining teeth.

4. The arc-extinguishing mechanism of the miniature circuit breaker according to claim 3, characterized in that: The grid plate teeth include a left end tooth (11), a middle tooth (12), and a right end tooth (13). The left end tooth (11) is provided on both the front and rear sides of the grid plate (1), the middle tooth (12) is provided on either the front or rear side of the grid plate (1), and the right end tooth (13) is provided on the other side. The grid plate connection holes include a left end connection hole (24), a middle connection hole (25), and a right end connection hole (26); adjacent grid plates (1) are installed and arranged in the arc extinguishing cover (2) in a front-to-back opposite manner.

5. The arc-extinguishing mechanism of the miniature circuit breaker according to claim 4, characterized in that: The grid plate (1) has a grid plate cavity (14) at one end away from the end connecting plate (23); adjacent grid plates (1) are arranged in opposite directions, and adjacent grid plate cavities (14) are staggered.

6. The arc-extinguishing mechanism of the miniature circuit breaker according to claim 4, characterized in that: The end connecting plate (23) includes a front bent portion (230), a middle connecting portion (231), and a rear bent portion (232), and the three are connected as a whole; the end of the front bent portion (230) away from the middle connecting portion (231) is fixedly connected to the front side plate (21), and the end of the rear bent portion (232) away from the middle connecting portion (231) is fixedly connected to the rear side plate (22); the exhaust hole is opened on the front bent portion (230), the rear bent portion (232), the front side plate (21), and the rear side plate (22).

7. The arc-extinguishing mechanism of the miniature circuit breaker according to claim 6, characterized in that: The end of the grid plate (1) near the end connecting plate (23) is adapted to the shape of the end connecting plate (23).

8. The arc-extinguishing mechanism of the miniature circuit breaker according to claim 4, characterized in that: The housing (3) is also provided with a moving contact (4), a stationary contact (7), an arc-starting plate (8), a coil (5), and a magnetic yoke (6). The magnetic yoke (6) is located on the upper side of the arc-extinguishing chamber, and the coil (5) is located in the magnetic yoke (6). The stationary contact (7) includes a stationary contact welding part (73), a stationary contact bending part (72), and a stationary contact magnetic conductive part (71). The stationary contact welding part (73) is fixedly connected to the coil (5), and the stationary contact magnetic conductive part (71) is located between the magnetic yoke (6) and the top surface of the arc-extinguishing chamber. The contact point on the stationary contact bending part (72) abuts against the moving contact (4). One end of the arc-starting plate (8) is located on the lower side of the arc-extinguishing chamber, and the other end extends to the outer periphery of the moving contact (4).

9. The arc-extinguishing mechanism of the miniature circuit breaker according to claim 8, characterized in that: The housing (3) includes a base (31) and a top cover (32), which are fastened and fixedly connected. The base (31) is provided with an upper yoke stop (30), a lower yoke stop (37), and a lower stop (36) for the magnetic conductive part of the stationary contact. The bottom surface of the magnetic yoke (6) is located between the upper yoke stop (30) and the lower yoke stop (37), and the magnetic conductive part (71) of the stationary contact is located between the lower yoke stop (37) and the lower stop (36) of the magnetic conductive part of the stationary contact.

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