Circuit breaker and movable contact mounting structure

Abstract

The application provides a new repulsion delay drop scheme different from the previous movable contact drop prevention mode and automatic rebound drop mode, by adding a damping structure during the repulsion drop action of the movable contact, the action time of the movable contact from repulsion to drop is prolonged, so that the total switch module has completed the short circuit opening action before the movable contact drops to contact the static contact, thereby realizing automatic drop without secondary short circuit and without adding an extra pushing mechanism.

Description

Technical Field

[0001] This invention relates to a circuit breaker and a moving contact mounting structure. Background Technology

[0002] A molded case circuit breaker (MCCB) is a protective device used in low-voltage power distribution systems. It provides multiple protection functions, including overload, short circuit, and leakage current protection, and is widely used in industrial, building, and household circuits. Its core feature is that it uses a high-strength plastic shell to enclose the internal components, providing both insulation and protection.

[0003] Currently, there are many types of molded case circuit breakers on the market. During normal operation, a spring is applied to the moving contact, allowing it to contact the stationary contact under spring pressure. Furthermore, according to product design requirements, the moving contact can only repel the stationary contact when the short-circuit current reaches, for example, more than 8 times its rated current (the multiple depends on the product design requirements); when the short-circuit current is less than 8 times the rated current, the moving contact cannot repel the stationary contact. Therefore, the spring needs to apply a certain force to the moving contact to keep it in contact with the stationary contact.

[0004] In other words, when a short circuit occurs and the short circuit current reaches, for example, more than 8 times its rated current, a very large repulsive force will be generated between the moving contact and the stationary contact, pushing the moving contact away from the stationary contact and thus separating the moving contact from the stationary contact. However, because the moving contact is subjected to the elastic pressure of a spring, the moving contact that was pushed away by the spring will bounce back and fall back into contact with the stationary contact, which may lead to a secondary short circuit.

[0005] In the past, in order to prevent the repelled moving contact from falling quickly under the action of the spring and coming into contact with the stationary contact, thus causing a secondary short circuit, the idea of ​​repelling stop was proposed. That is, after the moving contact is repelled, its stop position is fixed so that it cannot fall. This solution is also known as the moving contact anti-fall method. Summary of the Invention

[0006] However, adopting a moving contact anti-drop method will lead to new problems. That is, since the moving contact is fixed in the stop position after it is pushed open, when the main switch module closes again, external force is needed to push the moving contact out of the fixed position. This requires adding another pushing mechanism inside the circuit breaker, which will make the circuit breaker structure more complicated and increase the cost.

[0007] If the moving contact is not protected against falling, it will quickly rebound under the action of the spring after being pushed away (automatic rebound and falling). It is possible that the moving contact will rebound and fall into contact with the stationary contact before the short circuit breaking action of the main switch module is completed, thus causing a secondary short circuit.

[0008] The present invention was made in view of the above circumstances, and its purpose is to provide a novel repulsion delayed drop scheme that is different from the conventional moving contact anti-drop method and automatic rebound drop method. By adding a damping structure during the repulsion drop action of the moving contact, the action time of the moving contact from repulsion to drop is extended, so that the main switch module has completed the short circuit breaking action before the moving contact drops to contact the stationary contact. Thus, a secondary short circuit is not caused, and automatic drop is achieved without the need to add an extra pushing mechanism.

[0009] Technical solutions to solve technical problems

[0010] To address the aforementioned problems, the circuit breaker according to the first aspect of the present invention includes a moving contact assembly, a stationary contact assembly, a spring, and a main switch module for controlling the moving contact assembly.

[0011] During normal connection, the moving contact assembly is pressed against the stationary contact assembly by the elastic force of the spring.

[0012] In the event of a short circuit, the time from when the moving contact assembly repels the stationary contact assembly until the moving contact assembly falls back into the stationary contact assembly is greater than the time required for the main switch module to complete the disconnection action.

[0013] Furthermore, it also includes damping structures.

[0014] During the process from the moment the moving contact assembly is pushed away from the stationary contact assembly until it falls back to the stationary contact assembly, the damping structure acts on the moving contact assembly to delay its action time.

[0015] Furthermore, the process of the moving contact assembly moving from being repelled by the stationary contact assembly to falling back into the stationary contact assembly includes:

[0016] In the first stage, the moving contact assembly starts from the point where the stationary contact assembly is pushed away until the moving contact assembly is in the middle position;

[0017] The second stage is the period from the intermediate position to the final repulsion position of the moving contact assembly.

[0018] In the third stage, under the elastic force of the spring, the moving contact assembly falls from the repulsion end position to the intermediate position.

[0019] In the fourth stage, under the elastic force of the spring, the moving contact assembly falls from the intermediate position to contact the stationary contact assembly.

[0020] In the second and third stages, the damping structure acts on the moving contact assembly to delay its action time.

[0021] Furthermore, a damping structure is provided on the arc surface of the moving contact assembly that contacts the connecting shaft of the spring.

[0022] Furthermore, the arcuate surface of the moving contact assembly that contacts the connecting shaft of the spring includes a front section surface with a friction coefficient less than or equal to a first predetermined value and a rear section surface with a friction coefficient greater than or equal to a second predetermined value.

[0023] Furthermore, the spring is provided with a damping structure.

[0024] Furthermore, the spring includes a front section with an elastic coefficient less than or equal to a first threshold and a rear section with an elastic coefficient greater than or equal to a second threshold.

[0025] Furthermore, the spring has a delayed rebound function.

[0026] Furthermore, the process of the moving contact assembly from the moment it is repelled by the stationary contact assembly until it falls back into the stationary contact assembly includes:

[0027] In the first stage, the moving contact assembly starts from the point where the stationary contact assembly is pushed away until the moving contact assembly is in the middle position;

[0028] The second stage is the period from the intermediate position to the final repulsion position of the moving contact assembly.

[0029] In the third stage, under the elastic force of the spring, the moving contact assembly falls from the repulsion end position to the intermediate position.

[0030] In the fourth stage, under the elastic force of the spring, the moving contact assembly falls from the intermediate position to contact the stationary contact assembly.

[0031] The total time for the first to fourth stages is greater than the time required for the main switch module to complete the disconnection action.

[0032] The damping force of the moving contact assembly during the operation of the first and fourth stages is less than the damping force of the moving contact assembly during the operation of the second and third stages.

[0033] Furthermore, the time from when the moving contact assembly starts to be repelled by the stationary contact assembly until the moving contact assembly falls back into the stationary contact assembly is 10 to 20 ms.

[0034] The moving contact mounting structure according to the second aspect of the present invention includes a moving contact assembly and a spring.

[0035] The moving contact assembly has a damping structure on the arc surface that contacts the connecting shaft of the spring, so that when a short circuit occurs, the time from when the moving contact assembly starts to be pushed away by the stationary contact assembly until the moving contact assembly falls back to the stationary contact assembly is greater than the time required for the main switch module to complete the disconnection action.

[0036] Furthermore, the arcuate surface of the moving contact assembly that contacts the connecting shaft of the spring includes a front section surface with a friction coefficient less than or equal to a first predetermined value and a rear section surface with a friction coefficient greater than or equal to a second predetermined value.

[0037] Invention Effects

[0038] According to the circuit breaker of the present invention, by adding a damping structure during the repulsion and drop-off action of the moving contact, the action time of the moving contact from repulsion to drop-off is extended, so that the main switch module has completed the short-circuit breaking action before the moving contact drops to contact the stationary contact, thereby preventing secondary short circuits and achieving automatic drop-off without the need for additional pushing mechanisms.

[0039] Furthermore, according to the circuit breaker of the present invention, by making the damping force of the moving contact assembly small in the first stage from the start of repulsion to the predetermined intermediate position, the moving contact can be quickly separated from the stationary contact to pull a certain distance apart in the initial stage of repulsion, thereby avoiding the generation of electric arc. Attached Figure Description

[0040] Figure 1 This is a schematic diagram illustrating an example of the structure of the moving contact assembly and the stationary contact assembly in a circuit breaker according to an embodiment of the present invention.

[0041] Figure 2A This is a schematic diagram illustrating a specific structural example of the moving contact assembly in a circuit breaker according to an embodiment of the present invention.

[0042] Figure 2B This is a partially enlarged schematic diagram showing a specific structural example of the arc surface of the moving contact assembly in a circuit breaker according to an embodiment of the present invention, which contacts the connecting shaft of the spring.

[0043] Figure 3A , Figure 3B , Figure 3C This is a schematic diagram illustrating an example of the process by which the moving contact assembly in a circuit breaker according to an embodiment of the present invention moves from the start of repulsion through a predetermined intermediate position to the end of repulsion. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0045] For ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “up,” etc., may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figure. It should be understood that spatial relative terms are intended to include different orientations of the device used or operated in addition to those shown in the figure. For example, if the device in the figure were flipped, an element described as “below” or “under” other elements or features would be oriented as “above” other elements or features.

[0046] Unless otherwise specified, the terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms should be understood to have the meaning consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formalized manner, unless explicitly stated otherwise herein.

[0047] Circuit Breaker

[0048] The circuit breaker according to the embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0049] Figure 1 This is a schematic diagram illustrating an example of the structure of the moving contact assembly and the stationary contact assembly in a circuit breaker according to an embodiment of the present invention. Figure 2A This is a schematic diagram illustrating a specific structural example of the moving contact assembly in a circuit breaker according to an embodiment of the present invention.

[0050] like Figure 1 As shown, the circuit breaker according to the embodiments of the present invention includes a moving contact assembly 101, a stationary contact assembly 102, a spring (not shown in the figure), and a main switch module (not shown in the figure) for controlling the moving contact assembly 101. Furthermore, as an example, the circuit breaker may include three independent moving contact assemblies 101 and three corresponding stationary contact assemblies 102, but the present invention is not limited thereto. Furthermore, as... Figure 2A As shown, the moving contact assembly 101 consists of a moving contact piece 101a and a contact support member 101b. Furthermore, the moving contact assembly 101 and the spring constitute the moving contact mounting structure.

[0051] When normally connected, such as Figure 1 As shown, the moving contact assembly 101 is pressed against the stationary contact assembly 102 by the elastic force of the spring.

[0052] When a short circuit occurs, for example, when the short circuit current reaches, for example, more than 8 times the rated current, such as Figure 3A , Figure 3B , Figure 3C As shown, the moving contact assembly 101 will be repelled from the stationary contact assembly 102, and the moving contact assembly 101 will rotate in the housing around the central axis 1002 of the contact support 101b (clockwise rotation in the figure), thereby separating the moving contact assembly 101 from the stationary contact assembly 102 to realize the switch opening.

[0053] In this invention, by adding a damping structure during the repulsion and falling action of the moving contact assembly 101, the action time of the moving contact assembly 101 from repulsion to falling is extended, thereby making the time from the start of the moving contact assembly 101 repulsion from the stationary contact assembly 102 to the time when the moving contact assembly 101 falls back to the stationary contact assembly 102 greater than the time required for the main switch module to complete the disconnection action.

[0054] As an example, the time required for the main switch module to respond to a short circuit and trigger the completion of the disconnection action is 8ms. At this time, by adding a damping structure during the repulsion and falling action of the moving contact assembly 101, the time from the start of the repulsion of the moving contact assembly 101 from the stationary contact assembly 102 to the time when the moving contact assembly 101 falls back to the stationary contact assembly 102 is 10-20ms. However, the present invention is not limited to this.

[0055] As a way to add a damping structure during the repulsion and falling action of the moving contact assembly 101, for example, it includes: setting a damping structure on the arc surface 1001 of the moving contact assembly that contacts the connecting shaft 2001 of the spring; setting a damping structure on the spring; using a spring with a delayed rebound function, etc.

[0056] Next, use Figure 2B , Figure 3A , Figure 3B , Figure 3C The method of providing a damping structure on the arc surface 1001 of the moving contact assembly 101 that contacts the connecting shaft 2001 of the spring will be described in detail.

[0057] Figure 2B This is a partially enlarged schematic diagram showing a specific structural example of the arc surface of the moving contact assembly in a circuit breaker according to an embodiment of the present invention, which contacts the connecting shaft of the spring. Figure 3A , Figure 3B , Figure 3C This is a schematic diagram illustrating an example of the process by which the moving contact assembly in a circuit breaker according to an embodiment of the present invention moves from the start of repulsion through a predetermined intermediate position to the end of repulsion.

[0058] like Figure 2BAs shown, as an example, the arc surface 1001 of the moving contact assembly 101 that contacts the connecting shaft 2001 of the spring includes a front section surface 1001a with a friction coefficient less than or equal to a first predetermined value and a rear section surface 1001b with a friction coefficient greater than or equal to a second predetermined value.

[0059] Furthermore, the process of the moving contact assembly 101 from being repelled by the stationary contact assembly 102 until it falls back into the stationary contact assembly 102 can be broken down as follows:

[0060] Phase 1 ( Figures 3A to 3B In this first stage, the moving contact assembly 101 starts from the point where the stationary contact assembly 102 is pushed away until the moving contact assembly 101 is in the middle position;

[0061] Phase Two Figures 3B to 3C In the second stage, the moving contact assembly 101 moves from the middle position to the repulsion end position.

[0062] Phase Three Figures 3C to 3B In the third stage, under the elastic force of the spring, the moving contact assembly 101 falls from the repulsive final position to the middle position.

[0063] Phase 4 Figures 3B to 3A In the fourth stage, under the elastic force of the spring, the moving contact assembly 101 falls from the middle position to contact the stationary contact assembly 102.

[0064] Furthermore, preferably, in the second and third stages, the damping structure acts on the moving contact assembly 101 to delay its action time.

[0065] In the first stage, from the start of the repulsion of the moving contact assembly 101 to the predetermined intermediate position, the front surface 1001a of the moving contact assembly 101 with a smaller coefficient of friction contacts the connecting shaft 2001 of the spring and applies force to the connecting shaft 2001 (i.e., no damping structure is provided in the first stage). This allows the first stage of action to be completed quickly and neatly, and a sufficiently safe distance to be formed between the moving contact assembly 1001 and the stationary contact assembly 1002, which can minimize the generation of electric arc.

[0066] Furthermore, the repulsion final position refers to the final position where the moving contact assembly 101 continues to move outward and away from the stationary contact assembly 102 from the middle position (e.g., Figure 3C (As shown). In the second stage, from the middle position to the repulsive final position, the rear surface 1001b of the moving contact assembly 101 with a higher coefficient of friction contacts the connecting shaft 2001 of the spring and applies force to the connecting shaft 2001 (i.e., a damping structure can be provided in the second stage to delay the action time), such as... Figure 3B , Figure 3C As shown.

[0067] Furthermore, the "drop" refers to the process by which the moving contact assembly 101 springs back from its repelled final position to the stationary contact assembly 102 under the action of the spring. This process is also divided into two stages (i.e., the third stage and the fourth stage). In the third stage, under the action of the spring's elastic force, the moving contact assembly 101 drops from its repelled final position to the intermediate position; in the fourth stage, under the action of the spring's elastic force, the moving contact assembly 101 drops from the intermediate position to contact the stationary contact assembly 102.

[0068] Furthermore, the sum of the times for the first, second, third, and fourth stages must be greater than the time required for the main switch module to complete the disconnection action. As an example, the time required for the main switch module to respond to a short circuit and trigger the completion of the disconnection action is 8 ms, and the sum of the times for the first, second, third, and fourth stages is 10 ms. However, the present invention is not limited to this; the sum of the times for the first, second, third, and fourth stages can also be greater than 10 ms and less than or equal to 20 ms. Furthermore, preferably, the damping force of the moving contact assembly 101 during the operation of the first and fourth stages is less than the damping force of the moving contact assembly 101 during the operation of the second and third stages.

[0069] Therefore, the circuit breaker according to the present invention, by adding a damping structure during the repulsion and drop-off action of the moving contact, extends the action time of the moving contact from repulsion to drop-off, so that the main switch module has completed the short-circuit disconnection action before the moving contact drops to contact the stationary contact, thereby preventing secondary short circuits and achieving automatic drop-off without the need for additional pushing mechanisms.

[0070] Furthermore, according to the circuit breaker of the present invention, by making the damping force of the moving contact assembly small in the first stage from the start of repulsion to the predetermined intermediate position, the moving contact can be quickly separated from the stationary contact to pull a certain distance apart in the initial stage of repulsion, thereby avoiding the generation of electric arc.

[0071] In addition, in this invention, besides providing a damping structure on the arc surface 1001 of the moving contact assembly that contacts the connecting shaft 2001 of the spring (first method), a damping structure can also be provided on the spring (second method).

[0072] Specifically, as an example, the spring may include a front section with a smaller elastic coefficient (e.g., less than or equal to a first threshold) and a rear section with a larger elastic coefficient (e.g., greater than or equal to a second threshold). This allows for a smaller damping force in the first stage (from the start of repulsion to the intermediate position, and the fourth stage (from the intermediate position to contact with the stationary contact assembly 102) of the moving contact assembly 101, and a larger damping force in the second stage (from the intermediate position to the final repulsion position, and the third stage (from the final repulsion position to the intermediate position) of the moving contact assembly 101. Similar to the first method described above, this achieves the technical effects of "automatic falling without secondary short circuits, without the need for additional pushing mechanisms" and "rapid separation of the moving contact from the stationary contact at the very beginning of repulsion to create a certain distance, thereby preventing the generation of electric arcs."

[0073] Furthermore, in addition to the first method of providing a damping structure on the arc surface 1001 of the moving contact assembly that contacts the connecting shaft 2001 of the spring, and the second method of providing a damping structure on the spring, a third method using a spring with a delayed rebound function can also be adopted in this invention. Thus, similar to the first and second methods described above, the technical effects of "achieving automatic drop without secondary short circuits, without needing to add an extra pushing mechanism" and "allowing the moving contact to quickly separate from the stationary contact to create a certain distance at the initial stage of repulsion, thereby avoiding the generation of an electric arc" can also be achieved.

[0074] Furthermore, the first, second, and third methods described above can be flexibly combined to achieve the technical effects of "automatic drop without secondary short circuits, without the need for additional pushing mechanisms" and "rapid separation of the moving contact from the stationary contact at the initial stage of repulsion to create a certain distance, thereby avoiding the generation of electric arcs".

[0075] It should be understood that the above description is illustrative and not restrictive. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. Furthermore, many modifications can be made to adapt particular conditions or materials to the teachings of the various embodiments of the invention without departing from the scope of the invention. While the dimensions and types of materials described herein are used to define parameters of the various embodiments of the invention, the embodiments are not intended to be restrictive but are exemplary. Many other embodiments will become apparent to those skilled in the art upon reading the above description. Therefore, the scope of the various embodiments of the invention should be determined by reference to the appended claims and the full scope of their equivalents.

[0076] Industrial practicality

[0077] The circuit breaker and moving contact mounting structure of the present invention can be widely used in industrial, building and household circuits.

Claims

1. A circuit breaker, characterized in that, It includes a moving contact assembly, a stationary contact assembly, a spring, and a master switch module that controls the moving contact assembly. During normal connection, the moving contact assembly is pressed against the stationary contact assembly by the elastic force of the spring. In the event of a short circuit, the time from when the moving contact assembly repels the stationary contact assembly until the moving contact assembly falls back into the stationary contact assembly is greater than the time required for the main switch module to complete the disconnection action. A damping structure is provided on the arc surface of the moving contact assembly that contacts the connecting shaft of the spring. The arc surface of the moving contact assembly that contacts the connecting shaft of the spring includes a front section surface with a friction coefficient less than or equal to a first predetermined value and a rear section surface with a friction coefficient greater than or equal to a second predetermined value. The process of the moving contact assembly from being repelled by the stationary contact assembly until the moving contact assembly falls back into the stationary contact assembly includes: In the first stage, the moving contact assembly begins to move from the point where the stationary contact assembly is pushed away, passing through the front surface until the moving contact assembly is in the middle position. In the second stage, the moving contact assembly moves from the intermediate position through the rear section surface to the repulsion end position. In the third stage, under the elastic force of the spring, the moving contact assembly falls from the repulsion end position to the middle position via the rear section surface. In the fourth stage, under the elastic force of the spring, the moving contact assembly falls from the middle position through the front surface to contact the stationary contact assembly. The total time for the first to fourth stages is greater than the time required for the main switch module to complete the disconnection action. The damping force of the moving contact assembly during the operation of the first and fourth stages is less than the damping force of the moving contact assembly during the operation of the second and third stages.

2. The circuit breaker according to claim 1, characterized in that, The spring is equipped with a damping structure.

3. The circuit breaker according to claim 2, characterized in that, The spring includes a front section with an elastic coefficient less than or equal to a first threshold and a rear section with an elastic coefficient greater than or equal to a second threshold.

4. The circuit breaker according to claim 1, characterized in that, The spring has a delayed rebound function.

5. The circuit breaker according to any one of claims 1 to 4, characterized in that, The time from when the moving contact assembly starts to be pushed away by the stationary contact assembly until the moving contact assembly falls back into the stationary contact assembly is 10 to 20 ms.

6. A moving contact mounting structure, characterized in that, Including the moving contact assembly and the spring, The moving contact assembly has a damping structure on its arc surface that contacts the connecting shaft of the spring, so that in the event of a short circuit, the time from when the moving contact assembly is pushed away by the stationary contact assembly until the moving contact assembly falls back to the stationary contact assembly is greater than the time required for the main switch module to complete the disconnection action. The arc surface of the moving contact assembly that contacts the connecting shaft of the spring includes a front section surface with a friction coefficient less than or equal to a first predetermined value and a rear section surface with a friction coefficient greater than or equal to a second predetermined value. The process of the moving contact assembly from being repelled by the stationary contact assembly until the moving contact assembly falls back into the stationary contact assembly includes: In the first stage, the moving contact assembly begins to move from the point where the stationary contact assembly is pushed away, passing through the front surface until the moving contact assembly is in the middle position. In the second stage, the moving contact assembly moves from the intermediate position through the rear section surface to the repulsion end position. In the third stage, under the elastic force of the spring, the moving contact assembly falls from the repulsion end position to the middle position via the rear section surface. In the fourth stage, under the elastic force of the spring, the moving contact assembly falls from the middle position through the front surface to contact the stationary contact assembly. The total time for the first to fourth stages is greater than the time required for the main switch module to complete the disconnection action. The damping force of the moving contact assembly during the operation of the first and fourth stages is less than the damping force of the moving contact assembly during the operation of the second and third stages.

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