Contact tripping structure of molded case circuit breaker

Abstract

The utility model relates to the technical field of electrical protection equipment, in particular to a molded case circuit breaker contact tripping structure, which comprises a shell, and a protection assembly is mounted on one side, close to a moving contact, in the shell and used for protecting a static contact. Compared with the prior art, the circuit breaker has the advantages that the protection assembly is added in the breaking process of the contact, ablation of electric arcs to the surface of the contact is effectively reduced, the service life of the contact is remarkably prolonged, and the overall reliability of the circuit breaker is remarkably improved.

Description

Technical Field

[0001] This utility model relates to the field of electrical protection equipment technology, and in particular to a contact tripping structure for a molded case circuit breaker. Background Technology

[0002] With the widespread application of electrical equipment, circuit breakers, as important components for circuit protection, face increasingly stringent performance requirements. Currently, commonly available molded case circuit breakers generally employ electromagnetic tripping and thermal tripping to achieve their protective functions. However, traditional circuit breaker designs are prone to problems such as contact surface erosion, arc damage, and wear of protective components during long-term use, leading to unstable protection performance and affecting the safe operation of electrical equipment.

[0003] In the prior art, Chinese patent document CN206864417U, concerning a thermal trip system structure for a moving contact of a miniature circuit breaker, proposes overload protection by using a bimetallic strip to deform under heat and push a latch. It also employs a current path design combining bypass heating and direct heating, increasing the welding surface to reduce temperature rise. However, this structure still suffers from severe contact erosion due to arcing and slow tripping response when breaking large currents. Especially under short-circuit conditions, the electromagnetic tripping mechanism of the traditional structure often requires a long operating time, causing the contact system to be subjected to excessive electric repulsion and arcing, which seriously affects the electrical life of the circuit breaker. In addition, existing circuit breakers generally lack effective protection measures for stationary contacts, resulting in increased contact resistance after multiple breaks, affecting the long-term reliability of the product. Utility Model Content

[0004] In view of this, the purpose of this utility model is to propose a contact tripping structure for molded case circuit breakers to solve the problem of severe contact surface erosion in traditional circuit breakers.

[0005] To achieve the above objectives, this utility model provides a contact tripping structure for a molded case circuit breaker, comprising: a housing, an energized terminal installed on one side of the housing, a conductive plate installed on one side of the energized terminal, a stationary contact installed on one side of the conductive plate, a moving contact disposed inside the housing, and a protective component installed inside the housing near the moving contact, the protective component being used to protect the stationary contact.

[0006] Preferably, an arc-extinguishing chamber is provided at the end of the conductive plate, a load terminal is installed on the other side of the housing, a handle switch is rotatably installed on one side of the housing, a connecting arm is hinged to one end of the handle switch, the connecting arm is rotatably installed on one side of the housing, a moving contact is rotatably installed on the other end of the connecting arm, the moving contact is rotatably installed on one side of the housing, a moving contact is installed on the end of the moving contact away from the connecting arm, the moving contact abuts against the stationary contact, a first trigger handle is rotatably installed on the left side of the connecting arm, a second trigger handle abuts on one side of the first trigger handle, the second trigger handle is rotatably installed on one side of the housing, a bimetallic strip is installed on one side of the second trigger handle, an iron core abuts on the other side of the second trigger handle, an electromagnetic coil is sleeved on the iron core, one end of the electromagnetic coil is connected to the moving contact handle, the other end of the electromagnetic coil is connected to the bimetallic strip, the other end of the bimetallic strip is connected to the load terminal, and the iron core passes through the moving contact handle.

[0007] Preferably, the protective assembly includes a mounting block fixedly installed on one side of the housing, a rack slidably installed in the mounting block, a connecting rod fixedly installed on one side of the rack, one end of the connecting rod away from the rack fixedly installed on one side of the moving contact handle, a linkage handle rotatably installed on the side of the housing near the mounting block, a protective shell fixedly installed on one side of the linkage handle, a second groove provided on one side of the protective shell, the second groove being adapted to the stationary contact, and a gear fixedly installed on the side of the linkage handle near the rack, the gear meshing with the rack.

[0008] Preferably, the mounting block has an arc-shaped protrusion on the side near the moving contact, and a sliding groove is provided on the side of the mounting block near the rack, and the rack is slidably mounted in the sliding groove.

[0009] Preferably, a first groove is provided on the side of the linkage handle near the gear, and the first groove is adapted to the mounting block.

[0010] Preferably, the protective shell is a component made of BMC material.

[0011] The beneficial effects of this utility model are:

[0012] 1. This type of molded case circuit breaker contact tripping structure, through the installation of a protective component, causes the moving contact to generate an angular displacement around the rotation center when it is triggered. This rotational motion is converted into a linear displacement of the rack via a connecting rod. The rack slides along the groove of the mounting block, simultaneously driving the gear meshing with it to rotate. The gear further drives the linkage handle to rotate, thereby causing the protective shell fixed on the linkage handle to rotate. This ensures that the protective shell promptly covers the outside of the stationary contact, forming a protective enclosure to prevent the electric arc from directly burning the stationary contact and to block flying debris. The entire process is achieved by a purely mechanical structure, featuring rapid action, reliability, and maintenance-free operation.

[0013] 2. This type of molded case circuit breaker's contact tripping structure, through a tripping mechanism consisting of an electromagnetic coil, an iron core, a bimetallic strip, and a trigger handle, achieves rapid response to short-circuit and overload conditions. In the event of a short circuit, the electromagnetic coil instantly attracts the iron core, quickly driving the moving contact handle to complete the disconnection operation. Under overload conditions, the bimetallic strip bends due to heat, pushing the trigger handle to trip, thereby effectively cutting off the fault current. This purely mechanical transmission method requires no external power, has a fast response speed, and can ensure the interruption of short-circuit current within milliseconds, preventing the arc from continuing to burn. Simultaneously, the arc-extinguishing chamber works in conjunction with the protection components to quickly extinguish the arc and promptly shield the stationary contacts, effectively preventing direct erosion of the contact surface by the arc, thereby improving the circuit breaker's service life and operational safety. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the internal structure of this utility model;

[0016] Figure 2 This utility model Figure 1 Enlarged structural diagram at point A in the middle;

[0017] Figure 3 This is a schematic diagram of the disassembled structure of the protective component of this utility model.

[0018] The diagram is marked as follows:

[0019] 1. Housing; 2. Handle switch; 3. Connecting arm; 4. First trigger handle; 5. Moving contact handle; 6. Iron core; 7. Second trigger handle; 8. Bimetallic strip; 9. Arc extinguishing chamber; 10. Moving contact; 12. Stationary contact; 13. Linkage handle; 14. Protective shell; 15. Gear; 16. Rack; 17. Linkage rod; 18. Mounting block; 19. Slide groove; 20. First groove; 21. Second groove; 22. Power-on end; 23. Load end; 24. Conductive plate; 25. Electromagnetic coil. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments.

[0021] It should be noted that, unless otherwise defined, the technical or scientific terms used in this utility model should have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] like Figures 1 to 3As shown, the contact tripping structure of a molded case circuit breaker includes: a housing 1; an energized terminal 22 is installed on one side of the housing 1; a conductive plate 24 is installed on one side of the energized terminal 22; a stationary contact 12 is installed on one side of the conductive plate 24; a moving contact 10 is disposed inside the housing 1; a protection component is installed inside the housing 1 near the moving contact 10 to protect the stationary contact 12; an arc-extinguishing chamber 9 is disposed at the end of the conductive plate 24; a load terminal 23 is installed on the other side of the housing 1; a handle switch 2 is rotatably mounted on one side of the housing 1; a connecting arm 3 is hinged to one end of the handle switch 2; the connecting arm 3 is rotatably mounted on one side inside the housing 1; and a moving contact handle 5 is rotatably mounted on the other end of the connecting arm 3. The movable contact handle 5 is rotatably installed on one side inside the housing 1. A movable contact 10 is installed on the end of the movable contact handle 5 away from the connecting arm 3. The movable contact 10 abuts against the stationary contact 12. A first trigger handle 4 is rotatably installed on the left side of the connecting arm 3. A second trigger handle 7 abuts against one side of the first trigger handle 4. The second trigger handle 7 is rotatably installed on one side of the housing 1. A bimetallic strip 8 is installed on one side of the second trigger handle 7. An iron core 6 abuts against the other side of the second trigger handle 7. An electromagnetic coil 25 is sleeved on the iron core 6. One end of the electromagnetic coil 25 is connected to the movable contact handle 5. The other end of the electromagnetic coil 25 is connected to the bimetallic strip 8. The other end of the bimetallic strip 8 is connected to the load end 23. The iron core 6 passes through the movable contact handle 5.

[0023] During operation, this molded case circuit breaker connects the circuit after power is supplied by the moving contact 10 and the stationary contact 12. Current flows in from the energized end 22, flows out through the conductive plate 24, the stationary contact 12, the moving contact 10, and the load end 23, completing the energy transfer. When a short circuit fault occurs, the current in the circuit increases rapidly, and the electromagnetic coil 25 generates a strong electromagnetic attraction in a short time, causing the iron core 6 to move downward, which in turn moves the moving contact handle 5, causing the moving contact 10 to quickly separate from the stationary contact 12, achieving rapid circuit disconnection and short-circuit protection. When an overload fault occurs, the bimetallic strip 8 bends upward after being heated, pushing the second trigger handle 7 to move, which in turn moves the first trigger handle 4 and the connecting arm 3, causing the moving contact handle 5 to separate the moving contact 10 from the stationary contact 12, achieving overload protection. During the process of separating the moving contact 10 from the stationary contact 12, a current is generated. The high-temperature electric arc is promptly guided and extinguished by the arc-extinguishing chamber 9 at the end of the conductive plate 24, effectively preventing damage to internal components. Simultaneously, as the moving contact 10 disengages from the stationary contact 12, the movement of the moving contact handle 5 triggers the operation of the protective component inside the housing 1. This causes the protective component to be sleeved onto the outside of the stationary contact 12 during the breaking process, shielding and protecting the stationary contact 12. By setting up the protective component, the electric arc can be effectively shielded when the moving contact 10 and the stationary contact 12 are broken, preventing the electric arc from directly burning the surface of the stationary contact 12, significantly improving the service life of the stationary contact 12. At the same time, the protective component can block the splashing metal beads and carbon dust after the arc is extinguished, avoiding contamination and burning of other insulating components inside the housing 1, thereby improving the overall insulation performance and reliability of the circuit breaker, and ensuring the stability of the electrical and mechanical performance of the circuit breaker after multiple operations.

[0024] like Figure 2 , Figure 3 As shown, the protective assembly includes a mounting block 18 fixedly mounted on one side of the housing 1. A rack 16 is slidably mounted inside the mounting block 18. A connecting rod 17 is fixedly mounted on one side of the rack 16. One end of the connecting rod 17 away from the rack 16 is fixedly mounted on one side of the moving contact handle 5. A linkage handle 13 is rotatably mounted on the side of the housing 1 near the mounting block 18. A protective shell 14 is fixedly mounted on one side of the linkage handle 13. A second groove 21 is formed on one side of the protective shell 14. The second groove 21 is connected to the stationary contact. 12-phase compatibility; the mounting block 18 has an arc-shaped protrusion on the side near the moving contact 10, and a sliding groove 19 is provided on the side of the mounting block 18 near the rack 16, in which the rack 16 is slidably mounted; a gear 15 is fixedly mounted on the side of the linkage handle 13 near the rack 16, and the gear 15 meshes with the rack 16; a first groove 20 is provided on the side of the linkage handle 13 near the gear 15, and the first groove 20 is compatible with the mounting block 18; the protective shell 14 is a component made of BMC material;

[0025] The protective component operates as follows: when the moving contact 10 is triggered, it rotates around its rotation center at a certain angle. This rotational motion is converted into linear displacement through the rigid connection of the linkage 17. Specifically, the linkage 17 drives the rack 16, which is fixedly connected to it, to move axially downward along the groove 19 of the mounting block 18. The linear motion of the rack 16 is converted into rotational motion through its meshing with the gear 15. This rotational motion is transmitted to the protective shell 14 through the rigid structure of the linkage handle 13, causing the protective shell 14 to generate a corresponding angular displacement around the rotation center of the linkage handle 13. During this process, the protective shell 14 can completely cover the working surface of the stationary contact 12, forming a complete protective enclosure. The protective shell 14 adopts... Made of BMC (bulk molding compound) material, which has excellent insulation properties, mechanical strength, and arc resistance, it can effectively isolate the stationary contact 12 from external environmental corrosion and prevent the spread of arcs that may occur between contacts. Furthermore, the groove 19 on the mounting block 18 provides stable guiding support for the movement of the rack 16. The opening of the first groove 20 and the arc-shaped protrusion structure of the mounting block 18 ensure that the linkage handle 13 maintains a reasonable clearance fit with the mounting block 18 during rotation, thereby ensuring the reliability and durability of the system operation. This protection mechanism is realized through a purely mechanical structure and has the characteristics of rapid response, reliable operation, and maintenance-free operation, which significantly improves the safety and service life of the contact system in harsh working environments.

[0026] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples; within the framework of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in the details for the sake of brevity.

[0027] This utility model is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A contact tripping structure for a molded case circuit breaker, characterized in that, include: A housing (1) has an energized terminal (22) installed on one side of its interior. A conductive plate (24) is installed on one side of the energized terminal (22). A stationary contact (12) is installed on one side of the conductive plate (24). A moving contact (10) is provided inside the housing (1). A protective component is installed inside the housing (1) near the moving contact (10). The protective component is used to protect the stationary contact (12).

2. The contact tripping structure of the molded case circuit breaker according to claim 1, characterized in that, An arc-extinguishing chamber (9) is provided at the end of the conductive plate (24). A load end (23) is installed on the other side of the housing (1). A handle switch (2) is rotatably installed on one side of the housing (1). A connecting arm (3) is hinged to one end of the handle switch (2). The connecting arm (3) is rotatably installed on one side of the housing (1). A movable contact (5) is rotatably installed on the other end of the connecting arm (3). The movable contact (5) is rotatably installed on one side of the housing (1). A movable contact (10) is installed on the end of the movable contact (5) away from the connecting arm (3). The movable contact (10) abuts against the stationary contact (12). The connecting arm (3) A first trigger handle (4) is rotatably mounted on the left side. A second trigger handle (7) abuts against one side of the first trigger handle (4). The second trigger handle (7) is rotatably mounted on one side of the housing (1). A bimetallic strip (8) is mounted on one side of the second trigger handle (7). An iron core (6) abuts against the other side of the second trigger handle (7). An electromagnetic coil (25) is sleeved on the iron core (6). One end of the electromagnetic coil (25) is connected to the moving contact handle (5). The other end of the electromagnetic coil (25) is connected to the bimetallic strip (8). The other end of the bimetallic strip (8) is connected to the load end (23). The iron core (6) passes through the moving contact handle (5).

3. The contact tripping structure of the molded case circuit breaker according to claim 2, characterized in that, The protective assembly includes a mounting block (18) fixedly installed on one side of the housing (1), a rack (16) slidably installed in the mounting block (18), a connecting rod (17) fixedly installed on one side of the rack (16), one end of the connecting rod (17) away from the rack (16) fixedly installed on one side of the moving contact handle (5), a linkage handle (13) rotatably installed on the side of the housing (1) near the mounting block (18), a protective shell (14) fixedly installed on one side of the linkage handle (13), a second groove (21) is provided on one side of the protective shell (14), the second groove (21) is adapted to the stationary contact (12), and a gear (15) fixedly installed on the side of the linkage handle (13) near the rack (16), the gear (15) meshing with the rack (16).

4. The contact tripping structure of the molded case circuit breaker according to claim 3, characterized in that, The mounting block (18) has an arc-shaped protrusion on the side near the moving contact (10), and a sliding groove (19) is provided on the side of the mounting block (18) near the rack (16), and the rack (16) is slidably installed in the sliding groove (19).

5. The contact tripping structure of the molded case circuit breaker according to claim 4, characterized in that, A first groove (20) is provided on the side of the linkage handle (13) near the gear (15), and the first groove (20) is adapted to the mounting block (18).

6. The contact tripping structure of the molded case circuit breaker according to claim 5, characterized in that, The protective shell (14) is a component made of BMC material.

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