A moving contact for a molded case circuit breaker, and the molded case circuit breaker itself.

Abstract

This utility model discloses a moving contact for a molded case circuit breaker. The limiting surface of the moving contact is an arc-shaped concave surface, which is also connected to the tail end plane at the bottom of the moving contact. The tail end plane extends to the tail end of the moving contact. Under normal conditions, the stopping surface of the moving contact can abut against the rotating stop shaft in the molded case circuit breaker under the action of spring force. During a short circuit, the moving contact rotates around the moving contact rotation shaft under the action of electric repulsion force, so that the stopping surface, moving surface, and limiting surface of the moving contact come into contact with the rotating stop shaft in sequence, and the rotating stop shaft finally abuts against the limiting surface of the moving contact. The limiting surface of the moving contact is designed as an arc-shaped concave surface, which avoids stress concentration, makes the moving contact flatter overall, avoids excessive and large bending structures on the outer contour of the moving contact, and ensures that the local structure of the moving contact is fully matched with the overall strip structure of the moving contact, resulting in higher utilization of the moving contact blank.

Description

Technical Field

[0001] This utility model belongs to the technical field of molded case circuit breakers, specifically relating to a moving contact for a molded case circuit breaker and a molded case circuit breaker. Background Technology

[0002] The moving contact of a molded case circuit breaker is usually subjected to elastic pressure by a spring. When the molded case circuit breaker is working normally, the moving contact remains in contact with the stationary contact in the molded case circuit breaker under the elastic pressure of the spring. When the short-circuit current reaches more than a multiple of the rated current of the molded case circuit breaker, the moving contact repels, that is, the moving contact separates from the stationary contact under the action of electric repulsion, which plays a current limiting role in the short-circuit current of the molded case circuit breaker, thereby ensuring the safety of the power grid and equipment.

[0003] Reference Figure 1 , Figure 2 and Figure 3 Chinese utility model patent CN211929323U discloses a reversible moving contact structure. The moving contact 11 is an elongated strip structure. A raised moving contact stop surface 112 is located below the tail of the moving contact 11. One side of the moving contact stop surface 112 is connected to one end of the moving contact moving surface 111, and the other end of the moving contact moving surface 111 is connected to the moving contact limiting surface 113. A contact blade rotation shaft mounting hole 114 is provided at the lower part of the moving contact 11. The moving contact stop surface 112 is flat, the moving contact moving surface 111 is an arc surface, and the moving contact limiting surface 113 is a toothed surface. The lower tail of the moving contact 11 abuts against a rotation stop shaft 16. The spring mounting shaft 14 and the rotation stop shaft 16 are installed vertically in the lower rotating shaft groove. The upper spring hook 151 of the spring 15 is hung on the spring mounting shaft 14, and the lower spring hook 152 is hung on the rotation stop shaft 16. The moving contact stop surface 112 of the moving contact 11 engages with and is limited by the rotation stop shaft 16, which is the first limit. In the case of a short circuit, the moving contact 11 rotates around the contact blade rotating shaft 13, and the rotation stop shaft 16 engages with and is limited along the moving contact moving surface 111 to reach the moving contact limiting surface 113, which is the second limit.

[0004] Reference Figure 4 Chinese invention patent application CN102420082 A discloses a device to prevent the moving contact of a molded case circuit breaker from falling. The moving contact 2 has a mounting hole 21, through which the moving contact 2 is mounted on the contact pin. The moving contact 2 can rotate around the central axis of the mounting hole 21. The cam surface 20 is divided into a front stroke 22 and a rear stroke 23 with the vertex as the boundary. The slope of the rear stroke 23 is greater than that of the front stroke 22, so that when the moving pin 7 passes the vertex of the cam surface 20, it can quickly fall into the groove 24 on one side of the rear stroke 23 under the action of the contact spring 5.

[0005] The applicant noted that in the technical solution disclosed in CN211929323U, the moving contact contacts the rotating stop shaft of the molded case circuit breaker through a serrated structure on the moving contact when it is stopped. This contact area is small, making it prone to stress concentration. Especially when the moving contact rapidly opens during a large short-circuit current, the serrated structure of the moving contact collides with the rotating stop shaft, easily damaging the serrated structure and affecting the reliability and service life of the molded case circuit breaker. The technical solution disclosed in CN102420082 A uses a groove 24 to contact the moving shaft pin 7, which can avoid the stress concentration and damage to the serrated structure during collisions as in CN211929323U to some extent. However, the slope difference between its front stroke 22 and the bottom surface of the moving contact's tail is significant, causing the outer contour of the moving contact to form more or larger bends. This prevents the local structure of the moving contact from fully matching the overall strip structure of the moving contact. This results in complex molds and excessive waste in the manufacturing process of the moving contact. Utility Model Content

[0006] In view of this, the present invention provides a moving contact for a molded case circuit breaker and a molded case circuit breaker. The moving contact changes the traditional sawtooth-shaped moving contact limiting surface, and solves the technical problems of stress concentration when the moving contact is in the repulsive stop position and the presence of too many or too large bending structures on the outer contour of the moving contact.

[0007] The moving contact of a molded case circuit breaker provided by this utility model adopts the following technical solution:

[0008] A moving contact for a molded case circuit breaker, wherein the moving contact is provided with a moving contact rotation shaft mounting hole, and a downward protrusion is provided on the flat surface at the bottom of the moving contact, wherein the protrusion is provided with a moving contact stop surface, a moving contact moving surface and a moving contact limiting surface connected end to end in sequence;

[0009] The limiting surface of the moving contact is an arc-shaped concave surface, and the arc-shaped concave surface is also connected to the tail end plane at the bottom of the moving contact; the tail end plane extends to the tail end of the moving contact;

[0010] Under normal conditions, the moving contact stop surface can abut against the rotating stop shaft in the molded case circuit breaker under the action of spring force; during a short circuit, the moving contact is rotated around the moving contact rotation shaft by an electric repulsive force, so that the moving contact stop surface, the moving contact moving surface, and the moving contact limiting surface successively contact the rotating stop shaft, and the rotating stop shaft finally abuts against the moving contact limiting surface.

[0011] Furthermore, the moving contact moving surface includes a non-contact convex surface and a contact arc-shaped convex surface connected to each other. The non-contact convex surface is connected to the moving contact stop surface, and the contact arc-shaped convex surface is connected to the moving contact limiting surface.

[0012] The center of the arc-shaped convex surface is located at the center of the mounting hole of the rotating shaft of the moving contact, and its arc radius is R.

[0013] The distance from each point on the non-contact convex surface to the center of the mounting hole of the rotating shaft of the moving contact is less than R.

[0014] Furthermore, the tail end of the contact arc-shaped convex surface is connected to the head end of the moving contact limiting surface. When the moving contact rotates around the moving contact rotation axis under the electric repulsive force, the rotation stop shaft can contact the contact arc-shaped convex surface.

[0015] Furthermore, the first end of the non-contact convex surface is connected to the tail end of the moving contact stop surface;

[0016] When the moving contact rotates around the moving contact rotation axis under the electric repulsive force, the rotation stop shaft does not contact the non-contact convex surface.

[0017] Furthermore, the tail end of the non-contact convex surface is connected to the head end of the moving contact limiting surface;

[0018] The non-contact convex surface is an arc-shaped convex surface.

[0019] Furthermore, the central angle of the non-contact convex surface is larger than the central angle of the contact arc-shaped convex surface.

[0020] Furthermore, the moving contact limiting surface is provided with a wear-resistant layer.

[0021] Furthermore, the wall surface of the mounting hole for the rotating shaft of the moving contact is provided with a wear-resistant layer.

[0022] Furthermore, a self-lubricating layer is also provided on the wear-resistant layer of the mounting hole wall of the moving contact shaft.

[0023] Furthermore, the tail end plane and the top surface of the moving contact are connected by a vertical plane located in the up-down direction.

[0024] This utility model also provides a molded case circuit breaker, which includes the moving contact for a molded case circuit breaker as described above.

[0025] Beneficial effects:

[0026] 1. This utility model changes the traditional sawtooth-shaped moving contact limiting surface by designing it as a concave arc surface. This increases the contact area between the moving contact limiting surface and the rotating stop shaft, avoiding stress concentration and improving the reliability and service life of the molded case circuit breaker. Furthermore, the protrusion is located on the bottom plane of the moving contact, and the concave arc surface connects to the tail end plane of the bottom of the moving contact, extending all the way to the tail end of the moving contact. This makes the moving contact smoother overall, avoiding excessive and large bending structures on the outer contour of the moving contact. It also ensures a good match between the local structure of the moving contact and the overall strip structure, simplifying the manufacturing mold and increasing the utilization rate of the moving contact blank.

[0027] 2. The design of the contact arc-shaped convex surface of this utility model allows the moving contact to slide more smoothly to the repulsion stop position, and the rotating stop shaft to transition more smoothly from contact with the contact arc-shaped convex surface to contact with the moving contact limiting surface, thereby reducing the vibration caused by the repulsion process of the moving contact.

[0028] 3. The non-contact convex surface of this utility model ensures that the moving contact is not affected by the resistance of the rotating stop shaft during the initial repulsion stage, thus ensuring rapid separation from the stationary contact. The contact arc-shaped convex surface provides buffering in the subsequent stage through contact with the rotating stop shaft, avoiding violent collisions. This satisfies the requirements for the repulsion speed of the moving contact and reduces the vibration caused by the repulsion of the moving contact.

[0029] 4. In this utility model, there are no other curved or flat surfaces between the non-contact convex surface and the contact arc-shaped convex surface, which allows the moving contact to open smoothly without jamming.

[0030] 5. The central angle of the non-contact convex surface of this utility model is larger than that of the central angle of the contact arc-shaped convex surface, so that before the contact arc-shaped convex surface comes into contact with the rotating stop shaft, the moving contact can be pushed back to a sufficient safe distance from the stationary contact, thereby improving safety performance.

[0031] 6. The tail end plane and the top surface of the moving contact tail are directly connected by a vertical plane in the vertical direction, so that there are no other planes or curved surfaces between the tail end plane and the top surface of the moving contact tail. This further avoids the formation of too many or too large bending structures on the outer contour of the moving contact, making the moving contact manufacturing mold simpler and the moving contact blank processing utilization rate higher. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the moving contact structure for a molded case circuit breaker provided by existing technology;

[0033] Figure 2 yes Figure 1 Schematic diagram of the state when the moving contact and the stationary contact are in contact;

[0034] Figure 3 yes Figure 1Schematic diagram of the state when the moving contact is repelled;

[0035] Figure 4 This is a schematic diagram of another moving contact structure for a molded case circuit breaker provided by existing technology;

[0036] Figure 5 This is a schematic diagram of a moving contact for a molded case circuit breaker provided by this utility model;

[0037] Figure 6 yes Figure 5 Enlarged view of point A in the middle;

[0038] Figure 7 This is a schematic diagram of the trajectory circle provided by this utility model;

[0039] Figure 8 This is a schematic diagram of the contact state between the moving contact stop surface and the rotating stop shaft provided by this utility model;

[0040] Figure 9 This is a schematic diagram of the contact state between the moving surface of the moving contact and the rotating stop shaft provided by this utility model;

[0041] Figure 10 This is a schematic diagram of the contact state between the moving contact limiting surface and the rotating stop shaft provided by this utility model;

[0042] Figure 11 This is a schematic diagram of the three linked moving contact structures provided by this utility model;

[0043] Figures 1-3 In the middle, 11-moving contact, 111-moving contact moving surface, 112-moving contact stop surface, 113-moving contact limiting surface, 114-contact knife rotating shaft mounting hole, 12-rotating shaft, 13-contact knife rotating shaft, 14-spring mounting shaft, 15-spring, 16-rotation stop shaft, 3-stationary contact;

[0044] Figure 4 In the middle, 2-moving contact, 20-cam surface, 21-mounting hole, 22-first stroke, 23-second stroke, 24-groove;

[0045] Figures 5-11 In the diagram, 1-moving contact, 101-moving contact rotation shaft mounting hole, 102-moving contact stop surface, 103-moving contact moving surface, 104-moving contact limiting surface, 105-tail end plane, 106-moving contact top surface, 107-moving contact rotation shaft, 108-protrusion, 109-vertical plane, 2-track circle, 3-rotation stop shaft. Detailed Implementation

[0046] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0048] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” “third,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “two,” and similar terms, do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising,” “including,” and similar terms mean that the element or object preceding “comprising” or “including” encompasses the element or object listed following “comprising” or “including” and its equivalents, and do not exclude other elements or objects. The terms “connected,” “linked,” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0049] Example 1:

[0050] Reference Figures 5-11 This embodiment provides a moving contact for a molded case circuit breaker. The moving contact 1 is provided with a moving contact rotation shaft mounting hole 101. A downward protrusion 108 is provided on the flat surface at the bottom of the moving contact 1. The protrusion 108 is provided with a moving contact stop surface 102, a moving contact moving surface 103 and a moving contact limiting surface 104 connected end to end in sequence. The moving contact limiting surface 104 is an arc-shaped concave surface, which is also connected to the tail end plane 105 at the bottom of the moving contact 1. The tail end plane 105 extends to the tail end of the moving contact 1.

[0051] Reference Figure 8 Under normal conditions, the moving contact stop surface 102 can abut against the rotating stop shaft 3 in the molded case circuit breaker under the action of spring force; during a short circuit, the moving contact 1 rotates around the moving contact rotation shaft 107 under the electric repulsive force, causing the rotating stop shaft 3 to contact the moving contact stop surface 102, the moving contact moving surface 103, and the moving contact limiting surface 104 in sequence, and the rotating stop shaft 3 finally abuts against the moving contact limiting surface 104 (see Figure 10 When the rotating stop shaft 3 abuts against the moving contact limiting surface 104, the moving contact limiting surface 104 and the outer surface of the rotating stop shaft 3 are in contact, and the contact area is larger, which can disperse the contact stress.

[0052] Thus, this embodiment changes the traditional sawtooth-shaped moving contact limiting surface 104, designing it as a concave arc surface. This increases the contact area between the moving contact limiting surface 104 and the rotating stop shaft 3, avoiding stress concentration and improving the reliability and service life of the molded case circuit breaker. Furthermore, the protrusion 108 is located on the plane at the bottom of the moving contact 1, and the concave arc surface connects to the tail end plane 105 at the bottom of the moving contact 1. This tail end plane 105 extends all the way to the tail end of the moving contact 1, making the moving contact 1 flatter overall. This avoids excessive and large bending structures on the outer contour of the moving contact 1, ensuring a good match between the local structure of the moving contact 1 and the overall strip structure (i.e., making both the local and overall structures of the moving contact 1 more consistent with a straight strip structure). This simplifies the manufacturing mold for the moving contact 1 and increases the utilization rate of the moving contact 1 blank.

[0053] As a further improvement, the moving contact moving surface 103 includes a contact arc-shaped convex surface, the tail end of which is connected to the head end of the moving contact limiting surface 104, and the center of the corresponding circle of the contact arc-shaped convex surface is located at the center of the moving contact rotation shaft mounting hole 101, and the distance between the contact arc-shaped convex surface and the center of the moving contact rotation shaft mounting hole 101 is R. (Refer to...) Figure 9 When a short circuit occurs, the moving contact 1 rotates around the moving contact rotation shaft 107 under the electric repulsive force, and the rotation stop shaft 3 can make contact with the contact arc-shaped convex surface. Figure 7 In the process, the moving contact moving surface 103 and the trajectory circle 2 have a curve that coincides on the contact arc convex surface. The trajectory circle 2 is a circle with the center of the moving contact rotating shaft mounting hole 101 as the center and R as the radius.

[0054] Existing moving contact surfaces are generally composed of a steep section or cam surface with a large slope. CN211929323U and CN102420082 A, mentioned in the background art, both directly use a steep cam surface as the moving contact surface 103. In this embodiment, the design of the contact arc-shaped convex surface allows the moving contact 1 to slide more smoothly to the repulsion stop position. That is, it allows the rotating stop shaft 3 to transition more smoothly from contact with the contact arc-shaped convex surface to contact with the moving contact limiting surface 104, reducing vibration caused by the repulsion process of the moving contact 1.

[0055] Furthermore, in addition to the contact arc-shaped convex surface of the moving contact 103, the moving contact 103 also includes a non-contact convex surface. The first end of the non-contact convex surface is connected to the tail end of the moving contact stop surface 102. Moreover, the distance between the non-contact convex surface and the center of the moving contact rotation shaft mounting hole 101 is less than R. When the moving contact 1 rotates around the moving contact rotation shaft 107 under the electric repulsive force, the rotation stop shaft 3 does not contact the non-contact convex surface. Thus, during a short circuit, the non-contact convex surface first enables the moving contact 1 to achieve a large repulsion speed, allowing the moving contact 1 to quickly separate from the stationary contact to a safe distance (this safe distance ensures that the short-circuit current is reduced to below a set value), rapidly reducing the short-circuit current. After achieving a large repulsion speed, the moving contact 1 can be buffered by contacting the contact arc-shaped convex surface and the rotating stop shaft 3, allowing the moving contact 1 to slide more smoothly to the repulsion stop position. Compared with the prior art where the moving contact moving surface 103 is directly composed of a section of cam surface with a large slope, this embodiment makes the moving contact moving surface 103 have a contact arc-shaped convex surface and a non-contact convex surface connected end to end. The setting of the non-contact convex surface ensures that the moving contact 1 is not affected by the resistance of the rotating stop shaft 3 during the initial repulsion stage, ensuring rapid separation from the stationary contact. The contact arc-shaped convex surface then achieves buffering through contact with the rotating stop shaft 3 in the subsequent stage, avoiding violent collisions. This satisfies the requirements for the repulsion speed of the moving contact 1 and reduces the vibration caused by the repulsion of the moving contact 1.

[0056] More specifically, the tail end of the non-contact convex surface is connected to the head end of the moving contact limiting surface 104. That is, there are no other curved surfaces or planes between the non-contact convex surface and the contact arc-shaped convex surface, which allows the moving contact 1 to open smoothly without jamming. In this embodiment, the non-contact convex surface is an arc-shaped convex surface. Moreover, the central angle of the non-contact convex surface is larger than the central angle of the contact arc-shaped convex surface, so that before the contact arc-shaped convex surface contacts the rotating stop shaft 3, the moving contact 1 can be pushed back to a sufficient safe distance from the stationary contact, improving safety performance.

[0057] More specifically, refer to Figure 5 In this embodiment, the tail end plane 105 and the top surface 106 of the moving contact are directly connected by a vertical plane 109 located in the vertical direction. This means that there are not too many other planes or curved surfaces between the tail end plane 105 and the top surface 106 of the moving contact. This further avoids the formation of too many or too large bending structures on the outer contour of the moving contact 1, making the local structure of the moving contact 1 more compatible with the overall strip structure of the moving contact 1, making the mold for manufacturing the moving contact 1 simpler, and increasing the processing utilization rate of the moving contact 1 blank.

[0058] More specifically, in this embodiment, the first end of the non-contact convex surface is smoothly connected to the tail end of the moving contact stop surface 102. At the same time, the tail end of the non-contact convex surface is smoothly connected to the first end of the contact arc-shaped convex surface, and the tail end of the contact arc-shaped convex surface is smoothly connected to the first end of the moving contact limiting surface 104. Through the design of smooth connection, the continuity of the overall structure of the moving contact moving surface 103 is ensured. When the moving contact 1 rotates around the moving contact rotation axis 107 under the electric repulsive force, there will be no jamming or additional frictional resistance due to the abrupt structure at the connection. This ensures that the moving contact 1 can be quickly and smoothly repelled in the early stage of short circuit, reducing energy loss during the movement process, further improving the timeliness and reliability of the separation of the moving contact 1 from the stationary contact, reducing structural wear caused by stress concentration at the connection, and extending the service life of the moving contact 1. Furthermore, the smooth connection between the tail end of the moving contact limiting surface 104 and the tail end plane 105 ensures the continuity from the arc-shaped concave surface to the tail end plane 105, which conforms to the design concept of flattening the overall structure of the moving contact 1. It also reduces the additional stress generated on the tail end plane 105 after the rotating stop shaft 3 abuts against the moving contact limiting surface 104, thereby improving the structural stability.

[0059] In this embodiment, the protrusion 108 and the moving contact 1 body can be integrally formed. Furthermore, the surface of the moving contact limiting surface 104 can be provided with a wear-resistant layer (such as a ceramic coating, nickel-based alloy coating, molybdenum disulfide-based coating, etc.) or undergo other wear-resistant treatments to improve the wear resistance of the moving contact 1 and ensure a longer lifespan for the moving contact 1 under the impact of the rotating stop shaft 3. The wall surface of the moving contact rotating shaft mounting hole 101 can also be provided with a wear-resistant layer (such as a ceramic coating, nickel-based alloy coating, molybdenum disulfide-based coating, etc.) or undergo other wear-resistant treatments to improve the wear resistance of this mating part, reduce dimensional wear or deformation caused by friction during long-term use, and ensure the long-term stable fitting accuracy between the moving contact rotating shaft 107 and the moving contact rotating shaft mounting hole 101. Simultaneously, because common wear-resistant layers (such as ceramic coatings, nickel-based alloy coatings, molybdenum disulfide-based coatings, etc.) typically have low surface energy and good lubricity. For example, ceramic coatings (such as Al2O3 and Cr2O3) have high surface hardness and smoothness, which can reduce adhesive friction caused by direct contact between metals; coatings containing solid lubricants (such as molybdenum disulfide and graphite) have low interlayer shear force and can form a lubricating film at the friction interface, converting sliding friction into low-resistance shear motion within the coating, thereby reducing the coefficient of friction. Therefore, the wear-resistant layer on the wall of the moving contact rotating shaft mounting hole 101 can also reduce the coefficient of friction between the mounting hole and the moving contact rotating shaft 107, making the rotation of the moving contact 1 smoother during a short circuit, reducing the repulsion delay caused by excessive frictional resistance, ensuring the timely separation of the moving contact 1 from the stationary contact, thereby improving the short-circuit protection response speed and reliability of the molded case circuit breaker, and extending the overall service life of the moving contact 1. Understandably, in addition to the wear-resistant layer on the wall of the mounting hole 101 of the moving contact rotation shaft, a self-lubricating layer can be further added. The self-lubricating layer can be a polytetrafluoroethylene (PTFE) based coating, a graphite based coating, etc. The self-lubricating layer can continuously provide lubrication through the low shear strength of its own material. The wear-resistant layer and the self-lubricating layer together form a composite protection system of "wear resistance + self-lubrication". The wear-resistant layer acts as a base to resist the material loss caused by long-term friction, while the self-lubricating layer forms a stable lubricating film at the friction interface, further reducing the coefficient of friction. This is especially suitable for scenarios where the moving contact 1 rotates at high speed when short-circuited, reducing the risk of "dry friction".

[0060] Example 2:

[0061] Based on Embodiment 1, a molded case circuit breaker is provided, which includes the moving contact 1 in Embodiment 1.

[0062] In summary, the above are merely preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A movable contact for a molded case circuit breaker, characterized by, The moving contact (1) is provided with a moving contact rotation shaft mounting hole (101), and a downward protrusion (108) is provided on the bottom plane of the moving contact (1). The protrusion (108) is provided with a moving contact stop surface (102), a moving contact moving surface (103) and a moving contact limiting surface (104) connected end to end in sequence. The moving contact limiting surface (104) is a concave arc surface, and the concave arc surface is also connected to the tail end plane (105) at the bottom of the moving contact (1); the tail end plane (105) extends to the tail end of the moving contact (1); Under normal conditions, the moving contact stop surface (102) can abut against the rotating stop shaft (3) in the molded case circuit breaker under the action of spring force; during a short circuit, the moving contact (1) is rotated around the moving contact rotation shaft (107) by electric repulsion force, so that the moving contact stop surface (102), the moving contact moving surface (103), and the moving contact limiting surface (104) successively contact the rotating stop shaft (3), and the rotating stop shaft (3) finally abuts against the moving contact limiting surface (104).

2. The movable contact for a molded case circuit breaker of claim 1, wherein, The moving contact moving surface (103) includes a non-contact convex surface and a contact arc-shaped convex surface connected to each other. The non-contact convex surface is connected to the moving contact stop surface (102), and the contact arc-shaped convex surface is connected to the moving contact limiting surface (104). The center of the arc-shaped convex surface is located at the center of the mounting hole (101) of the moving contact rotating shaft, and its arc radius is R. The distance from each point on the non-contact convex surface to the center of the mounting hole (101) of the moving contact rotation shaft is less than R.

3. The moving contact for a molded case circuit breaker according to claim 2, characterized in that, The tail end of the contact arc-shaped convex surface is connected to the head end of the moving contact limiting surface (104). When the moving contact (1) rotates around the moving contact rotation axis (107) under the electric repulsive force, the rotation stop shaft (3) can contact the contact arc-shaped convex surface.

4. The movable contact for a molded case circuit breaker of claim 2, wherein, The first end of the non-contact convex surface is connected to the tail end of the moving contact stop surface (102); When the moving contact (1) rotates around the moving contact rotation axis (107) under the electric repulsive force, the rotation stop axis (3) does not contact the non-contact convex surface.

5. The movable contact for a molded case circuit breaker of claim 2, wherein, The tail end of the non-contact convex surface is connected to the head end of the moving contact limiting surface (104); The non-contact convex surface is an arc-shaped convex surface.

6. The movable contact for a molded case circuit breaker of claim 2, wherein, The central angle of the non-contact convex surface is greater than the central angle of the contact arc-shaped convex surface.

7. The movable contact of a molded case circuit breaker according to any one of claims 1 to 6, characterized in that The moving contact limiting surface (104) is provided with a wear-resistant layer.

8. The movable contact of a molded case circuit breaker according to any one of claims 1 to 6, characterized in that The wall surface of the mounting hole (101) for the rotating shaft of the moving contact is provided with a wear-resistant layer.

9. The movable contact for a molded case circuit breaker of claim 8, wherein, The wear-resistant layer on the wall of the moving contact rotating shaft mounting hole (101) is also provided with a self-lubricating layer.

10. The movable contact of a molded case circuit breaker according to any one of claims 1 to 6, characterized in that The tail end plane (105) and the top surface (106) of the moving contact are connected by a vertical plane (109) in the up-down direction.

11. A molded case circuit breaker characterized by, Including the moving contact for a molded case circuit breaker as described in any one of claims 1 to 10.

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