A contact repulsion self-locking mechanism and circuit breaker with sealing structure

Abstract

The application discloses a contact repulsion self-locking mechanism and a circuit breaker with a sealing structure, and the mechanism comprises a moving contact, a static contact, a rotating shaft, a contact pressure shaft, a pressing plate and a contact compression spring; the moving contact is connected with the rotating shaft through a moving contact rotating pivot hinge; the moving contact is provided with the contact pressure shaft, and the contact pressure shaft is in sliding fit with the pressing plate; the rotating shaft is connected with the pressing plate through a pressing plate rotating pivot; an installation cavity is formed between the pressing plate and the rotating shaft, and the contact compression spring is arranged in the installation cavity; when the moving contact is repelled by a short-circuit current to a preset position, the force of the pressing plate on the contact pressure shaft exceeds the center of the moving contact rotating pivot, so that the torque direction of the moving contact is reversed, and a self-locking torque is formed. The application further discloses a circuit breaker with a sealing structure. The application can effectively prevent the moving contact from being repelled and stuck and from being reset to be connected, has the technical effects of simple structure, easy installation, improved breaking reliability and service life.

Description

Technical Field

[0001] This invention relates to the field of low-voltage electrical technology, specifically to a contact repulsion self-locking mechanism and a circuit breaker with a sealing structure. Background Technology

[0002] As a critical protective electrical device in power systems, the core function of a circuit breaker is to quickly disconnect circuits and interrupt fault currents to protect electrical equipment and lines in the event of short circuits, overloads, or other faults. When a circuit breaker interrupts a short-circuit current, an electrodynamic force (Lorentz force, Hall force) is generated between the contacts. When this electrodynamic force exceeds the contact pressure, the contacts are repelled by the electrodynamic force, generating an electric arc between them. As the repulsion distance increases, the arc resistance increases. Under the action of the arc-extinguishing chamber, the arc is extinguished by deionization. Some of the arc is ejected from the arc-extinguishing nozzle of the circuit breaker through magnetic or air blowing. If the ejected arc particles are not effectively deionized, they can easily cause a secondary short circuit if they hit the external terminal block. The contact repulsion speed, repulsion distance, and breaking point stability directly determine the breaking capacity and current-limiting effect of the circuit breaker, while the insulation treatment of the arc-extinguishing nozzle determines the arc-extinguishing stability of the circuit breaker.

[0003] In the existing technology, the contact repulsion structure and arc-spraying insulation treatment of circuit breakers have many defects, resulting in insufficient breaking reliability. The specific problems are as follows:

[0004] 1. Reset problem: After the contacts are repelled, they are prone to fall back and reconnect. In some circuit breakers with repellent contacts, as the electric repulsion force decreases during the breaking process, the repellent contacts may revert and reconnect after being repelled, leading to contact burnout and breaking failure. This seriously affects the protection performance of the circuit breaker. This problem is more prominent, especially in the new energy field when the rated voltage reaches 1000V and above and the short-circuit current exceeds 40kA.

[0005] 2. Jamming problem: The contact opening process is prone to jamming and failure. Some structures use two independent torsion springs to achieve the limit, which can easily lead to the relative position of the torsion springs shifting, resulting in unstable clamping of the moving contact, which in turn causes jamming or limit failure.

[0006] 3. Limiting issues: The design of the repulsion limiting structure is unreasonable. Most existing limiting structures use a single limiting method, which has insufficient limiting force or low limiting accuracy. It cannot ensure that the contact remains stably in the open position after being repelled. Either the limiting is too loose, causing the contact to reset, or the limiting is too tight, causing the contact to fail to repel normally. At the same time, the fit between the limiting structure and the contact is unreasonable, which can easily generate lateral stress, exacerbating component wear and the risk of jamming.

[0007] 4. Secondary short circuit problem: An arc suppression cover is added to the arc nozzle, but when the customer connects the wires, the screw tightening part is exposed metal. The direction of the arc is not only forward, and some of it may fall. If it falls onto the wiring screw or terminal block, the circuit breaker with a system voltage of 1000V or above can easily be short-circuited and burned.

[0008] While existing technologies offer some improvements to address the aforementioned issues, they do not fundamentally solve the problems of contact jamming during repulsion, reset connection, and unstable limit switching. Furthermore, these technologies are complex in structure, difficult to assemble, unsuitable for the design requirements of small-volume circuit breakers, and prone to screw cover detachment. Therefore, there is an urgent need for a circuit breaker with a simple structure, reliable limit switching, and effective prevention of contact jamming and drop-out connection to improve the breaking reliability and service life of the circuit breaker. Summary of the Invention

[0009] The purpose of this invention is to provide a contact repulsion self-locking mechanism and a circuit breaker, thereby solving at least one technical problem existing in the prior art. In the prior art, due to the electrodynamic forces generated by the contacts during short-circuit breaking, the contacts easily fall back down and reconnect after being repulsed, leading to resetting, contact burnout, and breaking failure, which seriously affects the protective performance of the circuit breaker.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This application provides a contact repulsion self-locking mechanism, including: a moving contact, a stationary contact, a rotating shaft, a contact pressure shaft, a pressure plate, and a contact compression spring. The moving contact and the rotating shaft are hinged together by a moving contact rotation pivot. The moving contact is provided with a contact pressure shaft, which slides with the pressure plate and contacts the surface of the pressure plate.

[0011] The rotating shaft and the pressure plate are connected by a pivot for rotating the pressure plate. An installation cavity is formed between the pressure plate and the rotating shaft, and the contact spring is installed in the installation cavity.

[0012] When the moving contact is repelled to a preset position by the short-circuit current, the force exerted by the pressure plate on the contact pressure axis passes through the center of the moving contact's rotation pivot, causing the direction of the torque on the moving contact to reverse, forming a self-locking torque that holds the moving contact in the repelled and locked position. This restrains the moving contact to prevent it from falling back and accidentally closing.

[0013] Furthermore, the pressure plate includes: an arc-shaped plate, a transverse plate, and a longitudinal plate, which are connected in sequence to form a whole.

[0014] Furthermore, the contact pressure shaft slides along the surface of the pressure plate. During the upward movement of the moving contact in the repelled locking position, as the contact pressure shaft reaches the surface of the arc plate and continues to slide upward, the force transmitted to the moving contact through the pressure plate keeps the lever arm of the moving contact rotation pivot constant, thus achieving stable self-locking.

[0015] Furthermore, when the force exerted by the pressure plate on the contact pressure axis passes through the center of the rotating pivot of the moving contact and causes the direction of the torque on the moving contact to reverse, the torque is greater than the overturning torque generated by the weight of the moving contact itself.

[0016] Furthermore, the arc-shaped plate, the transverse plate, and the longitudinal plate are integrally injection molded or integrally bent. The longitudinal plate is provided with a pivot hole, and the pressure plate is pivotally connected to the pressure plate pivot through the pivot hole of the longitudinal plate.

[0017] Furthermore, the end of the contact spring that is close to the pressure plate along its own axial direction is connected to the pressure plate.

[0018] Furthermore, the angle between the transverse plate and the longitudinal plate is an obtuse angle.

[0019] Furthermore, the direction of the force exerted by the pressure plate on the contact pressure shaft is perpendicular to the surface of the pressure plate and passes through the center of the contact pressure shaft;

[0020] When the moving contact and the stationary contact are in closed contact, the contact spring is in a compressed state, and the pressure plate is subjected to the contact spring to generate a clockwise torque, pressing the moving contact and the stationary contact together.

[0021] When the moving contact and the stationary contact separate, the contact spring is in the released state. The pressure plate is subjected to the contact spring to form a counterclockwise torque, which restrains the moving contact and prevents the moving contact from falling back and closing accidentally.

[0022] Furthermore, the moving contact rotation pivot is limited and installed in the limiting groove opened in the rotating shaft. During the rotation of the moving contact, the angle α between the force direction of the contact pressure shaft and the wall of the limiting groove is less than 90°, thus constraining the moving contact rotation pivot to prevent it from coming off.

[0023] According to another aspect of this application, this application also provides a circuit breaker with a sealed structure, including the aforementioned contact repulsion self-locking mechanism and arc extinguishing protection system, both of which are installed on the circuit breaker. The circuit breaker can be a molded case circuit breaker or a frame circuit breaker.

[0024] Furthermore, the arc extinguishing protection system includes: an arc extinguishing chamber, a stationary contact cover, a protective cover base, and a protective cover top cover. The stationary contact cover and the protective cover base are assembled together in a nested sealed manner to form an insulating protective cavity surrounding the arc-generating port of the circuit breaker, which isolates the arc particles generated by the arc and blocks the conductive path of the arc particles falling to the wiring screws and exposed metal terminal blocks, thereby preventing secondary short circuits caused by arcing under high-voltage conditions.

[0025] Furthermore, the nested sealing assembly structure of the static contact cover and the protective cover base is a combination of any one or more of the following structural forms: slot embedded, toothed meshing, trapezoidal or elliptical groove.

[0026] The beneficial effects of this embodiment are as follows: it improves the breaking reliability and service life of the circuit breaker; it effectively prevents the moving contact from being stuck and resetting: through the pressure plate and the pressure spring, combined with the sliding cooperation between the contact pressure shaft and the pressure plate, the constant force arm after the moving contact is repelled achieves stable locking after the moving contact is repelled, and the limiting force is uniform and reliable, preventing the risk of the contact resetting and reconnecting after the electric repulsion force decreases; at the same time, the arc surface design and smooth transition of the pressure plate reduce the frictional resistance during the movement of the moving contact, avoids the jamming of the transmission components, and ensures that the contact opens quickly and smoothly.

[0027] During the rotation of the moving contact, the angle α between the force direction of the contact pressure axis and the wall of the limiting groove is less than 90°, thus ensuring that the rotating pivot of the moving contact will not slip out of the limiting groove. The structure is simple. It enables the contact to quickly open and then stably lock, preventing reset and reconnection, as well as jamming during opening. The structure is simple, easy to assemble, and suitable for circuit breakers of different sizes and voltage levels.

[0028] The arc spray nozzle nested sealing technology, where the static contact head cover and the protective cover base are nested and sealed, prevents secondary short circuits caused by short-circuit arc spraying.

[0029] In this embodiment, the structure is simple, easy to assemble, and highly stable, ensuring that the moving contact remains stably in the open position after being pushed back, reducing component wear and extending the service life of the circuit breaker; the overall structure is compact and suitable for the design requirements of small-volume circuit breakers. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a contact repulsion self-locking mechanism according to the present invention;

[0031] Figure 2 This is a schematic diagram of the closed state of a contact repulsion self-locking mechanism according to the present invention;

[0032] Figure 3 This is a schematic diagram of the repulsion separation state of a contact repulsion self-locking mechanism according to the present invention;

[0033] Figure 4 This is a structural schematic diagram showing the direction of the pressure plate force in the repulsion separation state of a contact repulsion self-locking mechanism according to the present invention;

[0034] Figure 5 This is a schematic diagram of the pressure plate of a contact repulsion self-locking mechanism according to the present invention;

[0035] Figure 6 This is a schematic diagram of the limiting groove of a contact repulsion self-locking mechanism according to the present invention;

[0036] Figure 7 This is a schematic diagram of a partial structure of a circuit breaker with a sealing structure according to the present invention;

[0037] Explanation of reference numerals in the attached drawings: 1. Moving contact; 2. Stationary contact; 3. Rotating shaft; 4. Contact pressure shaft; 5. Pressure plate; 51. Arc-shaped plate; 52. Transverse plate; 53. Longitudinal plate; 6. Contact compression spring; 7. Moving contact rotation pivot; 8. Pressure plate rotation pivot; 9. Arc extinguishing chamber; 10. Stationary contact cover; 11. Protective cover base; 12. Protective cover top cover; 13. Arc ejection nozzle insert. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0039] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention or simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0040] Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0041] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0042] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0043] This embodiment provides a contact pressure compensation structure, such as Figures 1 to 6 As shown, the contact repulsion self-locking mechanism is installed in the circuit breaker to solve the problem of resetting, contact burning, and failure to disconnect caused by the electrodynamic force generated by the contacts during the short circuit breaking process. This is because the contacts are easily re-fallen and reconnected after being repulsed, which seriously affects the protection performance of the circuit breaker.

[0044] Example 1

[0045] This embodiment 1 provides a contact repulsion self-locking mechanism, such as Figure 1 As shown, the contact repulsion self-locking mechanism includes: a moving contact 1, a stationary contact 2, a rotating shaft 3, a contact pressure shaft 4, a pressure plate 5, and a contact spring 6. The moving contact 1 and the rotating shaft 3 are hinged together via a moving contact rotation pivot 7. The moving contact is provided with a contact pressure shaft, which slides in cooperation with the pressure plate and contacts the surface of the pressure plate. When the moving contact 1 moves, it drives the contact pressure shaft 4 to move synchronously. The moving contact 1 and the moving contact pressure shaft 4 can be integrally formed or detachably connected. When detachably connected, it facilitates installation and maintenance. At this time, the moving contact pressure shaft presses down on the pressure plate and slides along the surface of the pressure plate. The rotating shaft 3 is installed on the circuit breaker base in the circuit breaker.

[0046] The rotating shaft 3 and the pressure plate 5 are connected by a pressure plate rotation pivot 8. An installation cavity is formed between the pressure plate and the rotating shaft. The contact spring 6 is installed in the installation cavity. The contact spring is low in cost, easy to source materials and install, and has good stability. The structure of the installation cavity needs to be similar to that of wrapping the contact spring to prevent the spring from loosening.

[0047] When the moving contact is repelled to a preset position by the short-circuit current, as shown in the comparison diagram, during the upward repulsion of the moving contact, the force exerted by the pressure plate 5 on the contact pressure axis passes through the center of the moving contact rotation pivot, causing the direction of the torque on the moving contact to reverse, forming a self-locking torque, and keeping the moving contact in the repelled and locked position. This restrains the moving contact to prevent it from falling back and closing accidentally.

[0048] The pressure plate 5 includes an arc-shaped plate 51, a horizontal plate 52, and a vertical plate 53. The arc-shaped plate, the horizontal plate, and the vertical plate are connected in sequence to form a whole. In this embodiment, it is integrally formed. The advantage of integral forming is that it is more stable, easier to process, and reduces the error caused by parts.

[0049] The contact pressure shaft 4 slides along the surface of the pressure plate 5. During the upward movement of the moving contact in the repulsion locking position, as the contact pressure shaft reaches the surface of the arc plate and continues to slide upward, the force transmitted to the moving contact through the pressure plate keeps the lever arm of the moving contact rotation pivot constant, thus achieving stable self-locking.

[0050] When the force exerted by the pressure plate 5 on the contact pressure shaft 4 passes through the center of the rotating pivot of the moving contact and causes the direction of the torque on the moving contact to reverse, the torque is greater than the overturning torque generated by the weight of the moving contact itself.

[0051] The arc-shaped plate 51, the transverse plate 52 and the longitudinal plate 53 can also be bent. The longitudinal plate is provided with a pivot hole. The pressure plate 5 is connected to the pivot of the pressure plate through the pivot hole of the longitudinal plate 53, so that the pressure plate rotates along the pivot of the pressure plate.

[0052] The contact spring 6 is connected to the pressure plate 5 at one end along its own axis near the pressure plate, and the other end of the contact spring 6 is connected to the rotating shaft 4. The contact spring can also be replaced by any equivalent elastic element among polyurethane elastic rubber block, rubber composite component with built-in spring, nitrogen hydraulic cylinder or flexible hinge.

[0053] The angle between the transverse plate 52 and the longitudinal plate 53 is an obtuse angle, that is, greater than 90°.

[0054] The direction of the force exerted by the pressure plate 5 on the contact pressure shaft 4 is perpendicular to the surface of the pressure plate and passes through the center of the contact pressure shaft, that is, the direction of the force passes through the center of the contact pressure shaft.

[0055] When the moving contact and the stationary contact are in closed contact, the contact spring is in a compressed state, and the pressure plate is subjected to the contact spring to generate a clockwise torque, pressing the moving contact and the stationary contact together.

[0056] When the moving contact and the stationary contact are in a repulsive separation state, the contact spring is in a released state. The pressure plate is subjected to the contact spring to form a counterclockwise torque, which restrains the moving contact and prevents the moving contact from falling back and closing accidentally.

[0057] The moving contact rotation pivot is limited and installed in the limiting groove opened in the rotating shaft 4. During the rotation of the moving contact, the angle α between the force direction of the contact pressure axis and the wall of the limiting groove is less than 90°, giving the moving contact rotation pivot an upward component force F. 分2 The pivot of the moving contact is constrained to prevent it from coming off.

[0058] According to another aspect of this embodiment, this application also provides a circuit breaker including the aforementioned contact repulsion self-locking mechanism, wherein the contact repulsion self-locking mechanism is installed in the circuit breaker. The circuit breaker can be a molded case circuit breaker or a frame circuit breaker.

[0059] The implementation process of this embodiment is as follows: When the circuit breaker is in the closed state, the moving contact is in contact with the stationary contact. At this time, the direction of the force exerted by the contact spring on the pressure plate is upward and to the right, pushing outward, i.e. Figure 2 As shown. At this time, the torque T1 from the contact spring on the pivot of the pressure plate rotation is clockwise. The pressure plate forms a clockwise torque with the pivot of the pressure plate rotation as the fulcrum, and the contact spring rotates along F1 in the rightward direction. At this time, the force exerted by the pressure plate on the moving contact is obliquely upward F. 压1 At this time, the moving contact is subjected to a torque of T2 from the pressure plate in a counterclockwise direction along the pivot axis of the moving contact, which applies a downward force to the moving contact, making the moving contact fit more tightly with the stationary contact.

[0060] When the moving contact is repelled by the combined effects of the Holm force and Lorentz force generated by the large short-circuit current, the circuit breaker is in a repelled separation state (the moving and stationary contacts are not in contact). When the moving contact is repelled to a certain height, the direction of the force exerted by the pressure plate on the moving contact is as follows: Figure 3 As shown, the direction of the force passes through the center of the moving contact's rotation pivot (i.e., the force changes from the right side of the center of the moving contact's rotation pivot to the left side), and the direction of the force is as follows. Figure 4 The F shown 压2 At this moment, the moving contact is subjected to a clockwise torque T2 by the pressure plate. This torque is greater than the torque due to the moving contact's own weight, so the moving contact is in a repelled and locked position and will not fall. The compression spring releases its elastic potential energy, constraining the movement of the moving contact and preventing it from falling back and accidentally closing the circuit breaker.

[0061] like Figure 3 As shown, the contact repulsion is achieved by the contact pressure shaft sliding on the pressure plate, thereby changing the force direction of the moving contact. After the contact repulsion, the contact pressure shaft continues to slide on the pressure plate. One end of the pressure plate has an arc-shaped structure, which makes the force arm of the moving contact a constant force arm, and the torque variation is very small. The variation mainly depends on the contact compression spring.

[0062] like Figure 6 The image shown is a partially enlarged view of the limiting groove structure. The angle α between the force direction of the contact pressure axis and the wall of the limiting groove is less than 90°, which ensures that F 分2 The upward leftward direction prevents the moving contact pivot from falling or wobbling.

[0063] The beneficial effects are as follows: The structure of the circuit breaker in this embodiment improves the breaking reliability and service life of the circuit breaker; effectively prevents the moving contact from being stuck and resetting: through the pressure plate and pressure spring, combined with the sliding cooperation between the contact pressure shaft and the pressure plate, the constant force arm after the moving contact is repelled achieves stable locking after the moving contact is repelled, and the limiting force is uniform and reliable, preventing the risk of the contact resetting and reconnecting after the electric repulsion force decreases; at the same time, the arc surface design and smooth transition of the pressure plate reduce the frictional resistance during the movement of the moving contact, avoid the transmission components from jamming, and ensure that the contact is repelled quickly and smoothly.

[0064] During the rotation of the moving contact, the angle α between the force direction of the contact pressure axis and the wall of the limiting groove is less than 90°, thus ensuring that the rotating pivot of the moving contact will not slip out of the limiting groove. The structure is simple. It enables the contact to quickly open and then stably lock, preventing reset and reconnection, as well as jamming during opening. The structure is simple, easy to assemble, and suitable for circuit breakers of different sizes and voltage levels.

[0065] Example 2

[0066] This embodiment provides a circuit breaker with a sealed structure, which can solve the technical problem of secondary short circuits. The circuit breaker includes the contact repulsion self-locking mechanism from Embodiment 1, such as... Figure 1-6 As shown. It also includes an arc-extinguishing protection system, with both the contact repulsion self-locking mechanism and the arc-extinguishing protection system installed on the circuit breaker. The arc-extinguishing protection system includes: an arc-extinguishing chamber 9, a stationary contact cover 10, a protective cover base 11, and a protective cover top cover 12. The stationary contact cover 10 and the protective cover base 11 are nested and sealed together to form an insulating protective cavity surrounding the arc-generating port of the circuit breaker, isolating arc particles generated by the arc and blocking the conductive path of arc particles falling to the wiring screws and exposed metal terminal blocks, thus preventing secondary short circuits caused by arcing under high-voltage conditions. A secondary arc-extinguishing device can be installed inside this protective cavity.

[0067] In this embodiment, the nested sealing assembly structure of the static contact cover and the protective cover base is a slot-embedded design, which makes it less likely for arc particles to fall off. The slot design shape can also be any of the following: toothed engagement, trapezoidal, or elliptical groove, or a combination of several shapes. However, in practice, for ease of processing and assembly, the more effective shape is... Figure 7 The "rectangular" recessed nesting and the other serrated nesting are both effective.

[0068] After the static contact cover and the protective cover base are nested and sealed, they completely cover the outside of the circuit breaker's arc nozzle and the exposed metal area of ​​the wiring terminals, forming a fully enclosed insulating shielding structure.

[0069] The working process is as follows: the arc particles generated by the moving contact and the stationary contact are extinguished through the arc extinguishing chamber 9. For the arc particles that are not cleaned, they enter the protective cover through the gap or through hole of the arc spraying port insert 13. Due to the nested and sealed design of the protective cover base and the stationary contact cover, the arc particles cannot enter the lower wiring terminal, i.e. the screw part.

[0070] The nested sealing technology at the jet nozzle in this embodiment, where the stationary contact head cover and the protective cover base are nested and sealed, can prevent secondary short circuits caused by short-circuit jetting.

[0071] In this embodiment, the structure is simple, easy to assemble, and highly stable, ensuring that the moving contact remains stably in the open position after being pushed back, reducing component wear and extending the service life of the circuit breaker; the overall structure is compact and suitable for the design requirements of small-volume circuit breakers.

[0072] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A contact repulsion self-locking mechanism, characterized in that, include: The moving contact (1), stationary contact (2), rotating shaft (3), contact pressure shaft (4), pressure plate (5) and contact spring (6) are provided. The moving contact (1) and rotating shaft (3) are hinged together by moving contact rotation pivot (7). The moving contact (1) is provided with contact pressure shaft (4), and the contact pressure shaft (4) is slidably engaged with pressure plate (5). The rotating shaft (3) and the pressure plate (5) are connected by the pressure plate rotation pivot (8). An installation cavity is formed between the pressure plate (5) and the rotating shaft (3). The contact spring (6) is installed in the installation cavity. When the moving contact (1) is repelled to a preset position by the short-circuit current, the force exerted by the pressure plate (5) on the contact pressure shaft (4) passes through the center of the moving contact rotation pivot (7), causing the direction of the torque on the moving contact to be reversed, forming a self-locking torque, and keeping the moving contact in the repelled and locked position.

2. The contact repulsion self-locking mechanism according to claim 1, characterized in that: The pressure plate (5) includes: an arc-shaped plate (51), a transverse plate (52) and a longitudinal plate (53), which are connected in sequence to form a whole.

3. The contact repulsion self-locking mechanism according to claim 2, characterized in that: The contact pressure shaft (4) slides along the surface of the pressure plate. During the process of the moving contact (1) moving upward in the repulsion locking position, the contact pressure shaft (4) reaches the surface of the arc plate and continues to slide upward. The force transmitted to the moving contact through the pressure plate keeps the lever arm of the moving contact rotation pivot constant, thereby achieving stable self-locking.

4. The contact repulsion self-locking mechanism according to claim 1, characterized in that: When the force exerted by the pressure plate (5) on the contact pressure shaft (4) passes through the center of the moving contact rotation pivot (7) and causes the direction of the torque on the moving contact to reverse, the torque is greater than the overturning torque generated by the weight of the moving contact itself.

5. The contact repulsion self-locking mechanism according to claim 2, characterized in that: The arc plate (51), the transverse plate (52) and the longitudinal plate (53) are integrally injection molded or integrally bent. The longitudinal plate is provided with a pivot hole, and the pressure plate is connected to the pivot shaft (8) of the pressure plate through the pivot hole of the longitudinal plate.

6. The contact repulsion self-locking mechanism according to claim 2, characterized in that: The contact spring (6) is connected to the pressure plate at one end along its own axis near the pressure plate.

7. The contact repulsion self-locking mechanism according to claim 1, characterized in that: The direction of the force exerted by the pressure plate (5) on the contact pressure shaft (4) is perpendicular to the surface of the pressure plate (5) and passes through the center of the contact pressure shaft; When the moving contact (1) and the stationary contact (2) are in contact, the pressure plate is subjected to the contact spring to generate a clockwise torque, pressing the moving contact and the stationary contact together; When the moving contact (1) and the stationary contact (2) are in a repulsive separation state, the pressure plate is subjected to the contact spring to form a counterclockwise torque, which constrains the moving contact (1) to prevent the moving contact from falling back and closing by itself.

8. The contact repulsion self-locking mechanism according to claim 1, characterized in that: The moving contact rotation pivot (7) is limited and installed in the limiting groove opened in the rotating shaft (3). During the rotation of the moving contact, the angle α between the force direction of the contact pressure shaft (4) and the wall of the limiting groove is less than 90°, which constrains the moving contact rotation pivot (7) to prevent it from falling out.

9. A circuit breaker with a sealed structure, characterized in that, Includes the contact repulsion self-locking mechanism and arc extinguishing protection system as described in any one of claims 1-9, wherein both the contact repulsion self-locking mechanism and the arc extinguishing protection system are installed on the circuit breaker.

10. The circuit breaker according to claim 9, characterized in that: The arc extinguishing protection system includes: an arc extinguishing chamber (9), a stationary contact cover (10), a protective cover base (11), and a protective cover top cover (12). The stationary contact cover (10) and the protective cover base (11) are assembled into one unit by nested sealing to form an insulating protective cavity surrounding the arc vent of the circuit breaker.

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