Moving contact structure of molded case circuit breaker
By designing the moving contact structure in the plastic-shell circuit breaker and adjusting the arc position of the rotating shaft to keep the spring lengthening unchanged, the multiple disadvantages of the circuit breaker when breaking the short-circuit current are solved, and more efficient current limiting effect is achieved. The moving contact opening speed ensures the reliability of the circuit breaker.
Patent Information
- Application Number
- CN202420348516.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-26
- Publication Date
- 2025-02-18
- Estimated Expiration
- 2034-02-26
AI Technical Summary
There are many disadvantages when existing plastic case circuit breakers break off short circuit current, including the inability to ensure the temperature rise of the circuit breaker, the wear of the contact leads to a drop in pressure, the opening speed of the moving contact is slowed, and it may even lead to a drop-back and breaking time too long. Increase the risk of circuit breaker failure.
A moving contact structure of a plastic shell circuit breaker is designed. By adjusting the arc position of the rotation axis, the spring lengthening amount is basically unchanged. The spring drives the shaft a to slide along the arc of the rotation axis to reduce the counterclockwise direction on the moving contact. Rotating torque ensures the moving contacts are opened quickly. The contact pressure is provided using a tensile spring, the structure is simpler, the design force value is basically the same as the calculated force value, and the actual operating status of the circuit breaker is simulated and calculated.
It effectively improves the current limiting effect of the circuit breaker when disconnecting large short-circuit current and the opening speed of the moving contacts, stability and reliability, ensuring that the circuit breaker reliably disconnects the short-circuit circuit.
Smart Images
Figure CN222507511U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of electrical equipment, in particular to a moving contact structure of a molded case circuit breaker. Background Art
[0002] In order to meet the temperature rise test requirements, molded case circuit breakers provide contact pressure between the moving and static contacts through the overtravel of the circuit breaker contact system to ensure good contact between the moving and static contacts and reduce the circuit resistance of the circuit breaker. Existing products generally ensure sufficient contact pressure when the circuit breaker leaves the factory. However, as the number of times the circuit breaker is opened and closed increases, the silver points of the moving and static contacts will wear due to arc burning and impact, resulting in a smaller overtravel of the contact system, and the contact pressure will also decrease. In this way, it is difficult to ensure the temperature rise of the circuit breaker, causing the circuit breaker to work in an abnormal state and reducing the service life of the circuit breaker. If the contact pressure is increased to ensure that it is within the normal contact range throughout the life cycle of the circuit breaker, it will cause excessive contact pressure and affect the current limiting effect of the circuit breaker. When there is a large short-circuit current (usually greater than 10kA), the moving and static contacts are difficult to separate, and the circuit breaker cannot effectively break the short-circuit current. In addition, when the current circuit breaker breaks the short-circuit current, the moving contact opens under the action of the electric repulsion force, but the contact spring force value will increase as the angle of the moving contact opening increases, which will reduce the opening speed of the moving contact and even cause the moving contact to fall back, resulting in a long breaking time and an increased risk of circuit breaker breaking failure.
[0003] In summary, existing circuit breakers have many disadvantages when breaking short-circuit currents, which can be summarized as follows:
[0004] ① First, in the prior art, the circuit breaker cannot ensure the effect of connecting normal current and breaking short-circuit current. As the number of times the circuit breaker is opened and closed increases, it is difficult to ensure the temperature rise of the circuit breaker due to arc burning and impact, causing the circuit breaker to work in an abnormal state and reducing its service life;
[0005] ② Secondly, when the contacts of the circuit breaker are worn, the contact pressure cannot be guaranteed and the thermal stability of the circuit breaker during operation cannot be improved;
[0006] ③ In addition, when the circuit breaker interrupts the short-circuit current, the moving contact opens under the action of the electric repulsion force. The contact spring force value will increase with the opening angle of the moving contact, which will reduce the opening speed of the moving contact and may cause the moving contact to fall back. Utility Model Content
[0007] In view of the deficiencies in the prior art, the utility model provides a moving contact structure of a molded case circuit breaker to solve the above problems.
[0008] In order to achieve the above objectives, the utility model is implemented through the following technical solutions.
[0009] A moving contact structure of a molded case circuit breaker, comprising a static contact, a moving silver point, a moving contact, a rotating shaft, a spring, a shaft a, and a shaft b, wherein the static contact corresponds to the moving contact position, the moving silver point is connected to the moving contact, both ends of the shaft b are fixed on the rotating shaft, and the middle part is arranged in the moving contact, the shaft a is provided with a shaft a end face and a spring groove a, one end of the spring is connected to the shaft a, and the other end is connected to the moving contact, the spring is provided with a spring beam, a spring straight edge, and a spring hook, the spring straight edges are symmetrically located on both sides of the spring beam, the spring hook is located below both sides of the spring as a whole, the moving contact is provided with a moving contact surface, a moving contact straight edge, a moving contact groove, a moving contact hole, and a moving contact fixing hole, and the spring is ensured by adjusting the corresponding position of the rotating shaft arc The amount of elongation remains basically unchanged, and the spring will drive shaft a to slide along the surface of the rotating shaft arc to ensure that the spring will not be elongated. The counterclockwise rotating torque acting on the moving contact becomes smaller. With the action of the electric repulsion force, the moving contact can be quickly opened until the arc is extinguished. The single-breakpoint moving contact structure uses a tension spring to provide contact pressure. Compared with the commonly used compression springs and torsion springs, the contact system structure is simpler, and the design force value is basically consistent with the calculated force value, which can better simulate and calculate the actual operating state of the circuit breaker. When breaking a large short-circuit current, the reaction torque of the spring becomes smaller as the contact repulsion increases, which can effectively improve the current limiting effect, increase the speed of opening the moving contact during breaking and the stability of the repulsion jam, and ensure reliable breaking of the short-circuit circuit.
[0010] Preferably, the moving silver spot is welded on the moving contact surface.
[0011] Preferably, the spring beam is hung in the moving contact slot.
[0012] Preferably, the spring hook is hung in the spring slot a.
[0013] Preferably, the end faces of the shaft a are arranged at both ends of the shaft a.
[0014] Preferably, the straight edge of the moving contact is located on the side of the moving contact facing the stationary contact.
[0015] Preferably, the shaft a is located in the moving contact hole.
[0016] Preferably, the middle portion of the shaft b is inserted into the moving contact fixing hole.
[0017] Preferably, the rotating shaft comprises a rotating shaft body, a rotating shaft arc, and a rotating shaft hole.
[0018] Preferably, the rotating shaft arc is arranged on a side of the rotating shaft body relative to the axis a, and the rotating shaft hole fixes the two ends of the axis b.
[0019] Compared with the prior art, the utility model discloses a moving contact structure of a molded case circuit breaker. By adjusting the corresponding position of the rotating shaft arc, the spring elongation is ensured to remain basically unchanged. The spring will drive the shaft a to slide along the surface of the rotating shaft arc to ensure that the spring will not be elongated, and the counterclockwise rotating torque acting on the moving contact becomes smaller. With the action of the electric repulsion force, the moving contact can be quickly opened until the arc is extinguished. The single-breakpoint moving contact structure uses a tension spring to provide contact pressure. Compared with the commonly used compression springs, torsion springs, etc., the moving contact device has a simpler structure, and the design force value is basically consistent with the calculated force value, which better simulates and calculates the actual operating state of the circuit breaker. When disconnecting a large short-circuit current, the reaction torque of the spring becomes smaller as the contact repulsion increases, which can effectively improve the current limiting effect, improve the speed of opening the moving contact during disconnection and the stability of the repulsion jam, and ensure reliable disconnection of the short-circuit circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a schematic diagram of the main structure of the moving contact structure of the molded case circuit breaker of the utility model;
[0021] Figure 2 It is a schematic diagram of the internal structure of the side of the moving contact structure of the molded case circuit breaker of the utility model;
[0022] Figure 3 This is a schematic diagram of the structure inside the moving contact of the molded case circuit breaker of the utility model;
[0023] Figure 4 It is a schematic diagram of the structure inside the rotating shaft of the moving contact structure of the molded case circuit breaker of the utility model;
[0024] Figure 5 This is a schematic diagram of the internal structure of the spring of the moving contact structure of the molded case circuit breaker of the utility model;
[0025] Figure 6 It is a schematic diagram of the internal structure of the movable contact structure axis a of the molded case circuit breaker of the utility model;
[0026] Figure 7 It is a structural schematic diagram of the structural torque of the moving contact of the molded case circuit breaker of the utility model;
[0027] Figure 8 It is a structural schematic diagram of the structural torque of the moving contact of the molded case circuit breaker of the utility model;
[0028] Fig. 9 It is a structural schematic diagram of the separation torque of the moving contact structure of the utility model molded case circuit breaker. DETAILED DESCRIPTION
[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.
[0030] A moving contact structure of a molded case circuit breaker, comprising a static contact 1, a moving silver point 2, a moving contact 3, a rotating shaft 4, a spring 5, a shaft a6, and a shaft b7, wherein the static contact 1 corresponds to the moving contact 3 in position, the moving contact 3 is connected to the moving silver point 2, both ends of the shaft b7 are fixed on the rotating shaft 4, and the middle part is penetrated in the moving contact 3, the shaft a6 is provided with a shaft a end face 6-1 and a spring groove a6-2, one end of the spring 5 is connected to the shaft a6, and the other end is connected to the moving contact 3, the spring 5 is provided with a spring crossbeam 5-1, a spring straight edge 5-2, and a spring hook 5-3, the spring straight edge 5-2 is symmetrically located on both sides of the spring crossbeam 5-1, the spring hook 5-3 is located below both sides of the spring 5 as a whole, the moving contact 3 is provided with a moving contact surface 3-1, a moving The movable contact straight edge 3-2, the movable contact slot 3-3, the movable contact hole 3-4, and the movable contact fixing hole 3-5, the movable silver point 2 is welded on the movable contact surface 3-1, the spring beam 5-1 is hung in the movable contact slot 3-3, the spring hook 5-3 is hung in the spring slot a6-2, the shaft a end face 6-1 is arranged at both ends of the shaft a6, the movable contact straight edge 3-2 is located on the side of the movable contact 3 facing the static contact 1, the shaft a6 is located in the movable contact hole 3-4, the middle part of the shaft b7 is penetrated in the movable contact fixing hole 3-5, the rotating shaft 4 includes a rotating shaft body 4-1, a rotating shaft arc 4-2, and a rotating shaft hole 4-3, the rotating shaft arc 4-2 is arranged on the side of the rotating shaft body 4-1 relative to the shaft a6, and the rotating shaft hole 4-3 fixes the two ends of the shaft b7.
[0031] like Figure 7-Figure 9 As shown, according to the moment balance, the final pressure F of the moving silver point 2 on the static contact 1 can be calculated 11 =F 21 *L 21 / L 11 , F 21 =k*ΔL 31 , assuming the silver point is worn to Figure 8 By adjusting the corresponding positions of the rotating shaft 4 and the rotating shaft arc 4-2, the elongation of the spring 5 is basically unchanged, that is, ΔL 32 =ΔL 31 , at this time F 22 =F 21 At this time, the arc 4-2 position of the rotating shaft 4 can also ensure that L 12 =L 11 At this time, F 12 =F 22 *L 22 / L 12=F 21 *L 21 / L 11 =F 11 Thereby ensuring that the contact pressure at this time is basically consistent with the initial contact pressure, ensuring the heat stability during actual use. When a short circuit current occurs, the moving contact 3 will rotate clockwise due to the electric repulsion of F3 and separate from the static contact 1. The spring 5 will drive the shaft a6 to slide along the arc 4-2 of the rotating shaft 4, ensuring that the spring 5 will not be stretched and keep F 23 unchanged, in addition, as the axis a6 moves, L 23 The counterclockwise torque F acting on the moving contact 3 decreases. 23 *L 23 Then, under the action of the electric repulsion force of F3, the moving contact 3 can be opened quickly until the arc is extinguished.
[0032] Working mode: The user can adjust the rotating shaft 4 to the corresponding rotating shaft arc 4-2 position to ensure that the elongation of the spring remains unchanged, and weld the moving silver point 2 to the moving contact surface 3-1 of the moving contact 3. When the moving contact 3 works together and the circuit breaker works, the moving silver point 2 contacts the static contact 1 to ensure that the circuit breaker is connected. The moving contact 3 will rotate clockwise due to the electric repulsion and separate from the static contact 1. The spring 5 will drive the shaft a6 to slide along the rotating shaft arc 4-2 of the rotating shaft 4, and the moving contact 3 can be quickly opened until the arc is extinguished.
[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.
[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.
[0035] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
Claims
1. A moving contact structure of a molded case circuit breaker, characterized in that: The invention comprises a stationary contact (1), a moving silver point (2), a moving contact (3), a rotating shaft (4), a spring (5), a shaft a (6), and a shaft b (7); the stationary contact (1) corresponds to the moving contact (3) in position; the moving silver point (2) is connected to the moving contact (3); both ends of the shaft b (7) are fixed to the rotating shaft (4), and the middle part is inserted into the moving contact (3); the shaft a (6) is provided with a shaft a end face (6-1) and a spring groove a (6-2); one end of the spring (5) is connected to the shaft a (6), and the other end is connected to the shaft b (7); One end is connected to the moving contact (3); the spring (5) is provided with a spring crossbeam (5-1), a spring straight edge (5-2), and a spring hook (5-3); the spring straight edges (5-2) are symmetrically located on both sides of the spring crossbeam (5-1); the spring hooks (5-3) are located below both sides of the spring (5); and the moving contact (3) is provided with a moving contact surface (3-1), a moving contact straight edge (3-2), a moving contact slot (3-3), a moving contact hole (3-4), and a moving contact fixing hole (3-5).
2. The moving contact structure of the molded case circuit breaker according to claim 1, characterized in that: The moving silver point (2) is welded on the moving contact surface (3-1).
3. The moving contact structure of the molded case circuit breaker according to claim 1, characterized in that: The spring crossbeam (5-1) is hung in the moving contact slot (3-3).
4. The moving contact structure of the molded case circuit breaker according to claim 1, characterized in that: The spring hook (5-3) is hung in the spring groove a (6-2).
5. The moving contact structure of the molded case circuit breaker according to claim 1, characterized in that: The end faces (6-1) of the shaft a are arranged at both ends of the shaft a (6).
6. The moving contact structure of the molded case circuit breaker according to claim 1, characterized in that: The straight edge (3-2) of the moving contact is located on the side of the moving contact (3) facing the stationary contact (1).
7. The moving contact structure of the molded case circuit breaker according to claim 1, characterized in that: The shaft a (6) is located in the moving contact hole (3-4).
8. The moving contact structure of the molded case circuit breaker according to claim 1, characterized in that: The middle part of the shaft b (7) is inserted into the moving contact fixing hole (3-5).
9. The moving contact structure of the molded case circuit breaker according to claim 1, characterized in that: The rotating shaft (4) comprises a rotating shaft body (4-1), a rotating shaft arc (4-2), and a rotating shaft hole (4-3).
10. The moving contact structure of the molded case circuit breaker according to claim 9, characterized in that: The rotating shaft arc (4-2) is arranged on a side of the rotating shaft body (4-1) opposite to the axis a (6), and the rotating shaft hole (4-3) fixes the two ends of the axis b (7).