Moving contact structure
By adding a limit shaft and a torsion spring to the rotating shaft, the problem of the moving contact falling back under fault current is solved, realizing stable contact opening and effective interruption of fault current, thus improving the safety and reliability of the circuit breaker.
Patent Information
- Application Number
- CN202520173760.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-26
- Publication Date
- 2026-01-09
- Estimated Expiration
- 2035-01-26
AI Technical Summary
Existing molded case circuit breakers are prone to having their moving contacts fall back under fault current, leading to the risk of welding, affecting the current limiting effect and posing a safety hazard.
A limiting shaft and a torsion spring are added to the rotating shaft. By changing the contact surface between the limiting shaft and the moving guide rod, the moving guide rod is prevented from falling back, ensuring that the contacts do not weld together and effectively interrupting the fault current.
This effectively prevents the moving guide rod from falling back under fault current, ensures that the contacts do not weld together, improves the fault current breaking capacity, and extends the service life and reliability of the circuit breaker.
Smart Images
Figure CN223785113U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of low-voltage electrical appliance technology, specifically relating to a moving contact structure. Background Technology
[0002] The aforementioned rotating shaft is a crucial component of the operating mechanism of a molded case circuit breaker, serving three functions: connection, rotation, and protection. The connection function links the moving contacts together, enabling the circuit breaker's opening and closing operations via the rotating shaft. The rotation function involves the rotating shaft, typically installed within the circuit breaker's mechanism, connecting to the stationary and moving contacts via retaining rings and sliding couplings. When the handle rotates, the rotating shaft moves, driving the moving contacts to open the circuit breaker. The protection function addresses the issue that during the circuit breaker's opening process, the moving contacts may collide, potentially causing wear or damage. Because the rotating shaft is relatively robust and wear-resistant, it effectively reduces this collision friction, extending the circuit breaker's service life and improving its reliability and stability.
[0003] In summary, the aforementioned molded case circuit breakers, installed in conductive circuits, can close, carry, and interrupt current under normal circuit conditions. They can also interrupt fault currents within a specified time when a fault current occurs in the conductive circuit, preventing major accidents. When interrupting large currents, molded case circuit breakers generally use the principle of electro-repulsion to achieve current limiting. At the initial stage of current interruption, the electro-repulsion force on the moving contact includes the Lorentz force generated by the circuit and the Holm force generated at the contact point due to the contraction of the circuit lines. However, once the contacts open, the Holm force disappears, leaving only the Lorentz force. This can negatively impact the opening process. For example, under the combined action of the contact spring force, there is a risk of contact fallback, which not only affects the current limiting effect but can also cause severe contact burn-out or even welding, leading to damage to load components by the fault current and posing a significant safety hazard. Utility Model Content
[0004] The objective of this invention is to provide a moving contact structure that helps prevent the moving conductor from falling back under fault current, thus ensuring that the contact is not welded and facilitating the interruption of fault current.
[0005] The present invention achieves its objective as follows: a moving contact structure includes a rotating shaft, a moving guide rod, and a torsion spring. The end of the moving guide rod facing the rotating shaft is rotatably mounted on the rotating shaft via a pivot shaft, while the end of the moving guide rod away from the rotating shaft is a free end. The torsion spring is mounted on the pivot shaft. The structure also includes a limiting shaft located on the rotation path of the moving guide rod and slidably mounted within a groove formed on the rotating shaft. The end of the torsion spring facing the groove abuts against the limiting shaft, and the end of the torsion spring facing the moving guide rod abuts against the moving guide rod. The moving guide rod has a first contact surface and a second contact surface. During the repulsion process, the moving guide rod rotates clockwise. When the first contact surface of the moving guide rod contacts the limiting shaft and pushes the limiting shaft to slide along the groove, causing the moving guide rod to disengage from the stop of the limiting shaft and reach the maximum repulsion position, if the moving guide rod rotates counterclockwise at this point, the limiting shaft contacts the second contact surface of the moving guide rod, keeping the moving guide rod in the repulsion position.
[0006] In a specific embodiment of this utility model, the torsion spring disposed on the pivot shaft of the moving guide rod is a double helical torsion spring, and has a pair of corresponding limiting shaft abutments at one end, while the other end is configured as... The shape of the letter is fitted onto the moving guide rod and abuts against the moving guide rod abutment foot. A pair of limiting shaft abutment feet abut against the upward side of the limiting shaft that is slidably disposed in the slide groove, while the moving guide rod abutment foot abuts against the end of the moving guide rod facing the rotating shaft and against the downward side of the moving guide rod.
[0007] In another specific embodiment of this utility model, the moving guide rod abuts against the side of the moving guide rod facing upward in the state of a saddle cover.
[0008] In another specific embodiment of this utility model, the rotating shaft is provided with rotating shaft cavities spaced apart from each other in the length direction, the number of which is equal to the number of moving guide rods. On the cavity wall of the rotating shaft cavity on the opposite side and at corresponding positions, a recessed part is formed in the cavity wall, which forms the sliding groove. The left and right ends of the limiting shaft are respectively slidably engaged with the sliding groove.
[0009] In another specific embodiment of this utility model, a moving guide rod arc transition flange clearance groove is formed on the bottom wall of the rotating shaft cavity and at the center of the bottom wall. A moving guide rod arc transition flange is formed at one end of the moving guide rod facing the rotating shaft cavity and below the first contact surface of the moving guide rod. The moving guide rod arc transition flange corresponds to the moving guide rod arc transition flange clearance groove.
[0010] In a more specific embodiment of this utility model, the groove is trapezoidal in shape, wider at the top and narrower at the bottom.
[0011] In a further specific embodiment of this utility model, the cross-sectional shape of the arc transition flange clearance groove of the moving guide rod is as follows: The shape is T-shaped, and the width is adapted to the thickness of the moving guide rod.
[0012] The technical solution provided by this utility model adds a limiting shaft to the rotating shaft, and the torsion spring, which is loosely fitted on the pivot shaft of the moving guide rod, abuts against the limiting shaft at one end facing the slide groove formed on the rotating shaft, while the other end abuts against the moving guide rod. By changing the contact surface between the limiting shaft and the moving guide rod, it helps to prevent the moving guide rod, which is repelled under fault current, from falling back, thus ensuring that the contacts are not welded and facilitating the interruption of fault current. Attached Figure Description
[0013] Figure 1 This is an assembly structure diagram of the present invention;
[0014] Figure 2 for Figure 1 Overall structural diagram after assembly;
[0015] Figure 3 for Figure 1 The detailed structural diagram of the moving guide rod is shown.
[0016] Figure 4 for Figure 1 The diagram shows a torsion spring loosely fitted on the pivot shaft of the moving guide rod and the limiting shaft abutting the foot against the limiting shaft.
[0017] Figure 5 The diagram shows the torsion spring's limiting shaft abutment foot and the moving guide rod abutment foot in abutment with the limiting shaft and the moving guide rod, respectively.
[0018] Figure 6 for Figure 1 The diagram shows the first contact surface of the moving guide rod contacting the limiting shaft during the repulsion process of the moving guide rod;
[0019] Figure 7 for Figure 1 The diagram shows the moving guide rod rotating clockwise under the action of power and reaching the maximum repulsion position.
[0020] Figure 8 for Figure 1 The diagram shows the second contact surface of the moving guide rod contacting the limiting shaft, and the limiting shaft preventing the moving guide rod from continuing to rotate, thus keeping it in the repelled position. Detailed Implementation
[0021] In order to better understand the technical essence and beneficial effects of this utility model, the applicant provides a detailed description below by way of embodiments. However, the description of the embodiments is not intended to limit the solution of this utility model. Any formal but not substantive equivalent transformations made based on the concept of this utility model should be considered within the scope of the technical solution of this utility model.
[0022] In the following description, all directional or positional concepts involving up, down, left, right, front, and back are based on the current position. Figure 1 The location and state of the object are taken as examples, and therefore should not be construed as a special limitation on the technical solution provided by this utility model.
[0023] Please see Figure 1 and Figure 2 The diagram shows a rotating shaft 1, a movable guide rod 2, and a torsion spring 3. The end of the movable guide rod 2 facing the rotating shaft 1 (i.e., the front end in the illustrated position) is rotatably mounted on the rotating shaft 1 via a movable guide rod pivot 5, while the end of the movable guide rod 2 away from the rotating shaft 1 (i.e., the rear end in the illustrated position) is a free end. The middle portion of the torsion spring 3 is loosely fitted onto the movable guide rod pivot 5. Figure 1 As shown, at one end of the moving guide rod 2, i.e. Figure 1 The front end of the indicated position has a movable guide rod pivot hole 24, through which the movable guide rod is pivotally connected to the aforementioned movable guide rod pivot shaft 5. Furthermore, via... Figure 1 and Figure 2 As can be seen from the diagram, since there are three moving guide rods 2 that pivotally cooperate with the pivot shaft 5, there are three corresponding moving guide rod pivot shafts 5, and three torsion springs 3 as mentioned above, it can be determined that the application object of this utility model is a three-pole circuit breaker. More specifically, the rotating shaft structure of this utility model is the rotating shaft of the structural system of a three-pole molded case circuit breaker. However, it is not affected by the fact that this utility model is based on... Figure 1 and Figure 2 The limit on the number of poles of the molded case circuit breaker shown can be adapted to changes in the number of poles of the molded case circuit breaker in actual situations.
[0024] The key technical points of the technical solution provided by this utility model are as follows: the structure system of the aforementioned rotating shaft structure also includes a limiting shaft 4 located on the rotation path of the aforementioned rotating shaft 1 and slidably disposed in the slide groove 11 formed on the rotating shaft 1. The end of the aforementioned torsion spring 3 facing the aforementioned slide groove 11 abuts against the limiting shaft 4, and the end of the torsion spring 3 facing the moving guide rod 2 abuts against the moving guide rod 2. The moving guide rod 2 has a first contact surface 21 and a second contact surface 22. During the repulsion process of the moving guide rod 2, the moving guide rod 2 rotates clockwise. When the first contact surface 21 of the moving guide rod contacts the limiting shaft 4 and pushes the limiting shaft 4 to slide along the slide groove 11, the moving guide rod 2 disengages from the stop of the limiting shaft 4 and reaches the maximum repulsion position. At this time, if the moving guide rod 2 rotates counterclockwise, the limiting shaft 4 contacts the second contact surface 22 of the moving guide rod, so that the moving guide rod 2 remains in the repulsion position.
[0025] See you later Figure 1 The aforementioned torsion spring 3, which is loosely fitted in the middle and pivoted on the aforementioned moving guide rod pivot 5, is a double helical torsion spring, and at one end (such as...) Figure 1 The front end (as shown in the position state) is equipped with a pair of corresponding limiting shaft abutment feet 31, while at the other end (such as...) Figure 1 The rear end of the position state shown is configured as follows: The U-shaped abutment rests against the moving guide rod abutment foot 32 in a state of being sleeved on the moving guide rod 2. A pair of limiting shaft abutment feet 31 abut against the upward side of the aforementioned limiting shaft 4 which is slidably disposed in the aforementioned slide groove 11, while the moving guide rod abutment foot 32 abuts against the end of the aforementioned moving guide rod 2 facing the aforementioned rotating shaft 1 and against the downward side of the moving guide rod 2.
[0026] Depend on Figure 2 As shown, the aforementioned moving guide rod abutment foot 32 abuts against the upward-facing side of the aforementioned moving guide rod 2 facing the aforementioned rotating shaft 1 in a saddle-like state.
[0027] Please see Figures 3 to 4 And combined Figure 1 The end face of the aforementioned movable guide rod 2 facing the aforementioned rotating shaft 1 is configured as the first contact surface 21 of the movable guide rod, while the surface of the movable guide rod 2 facing the rotating shaft 1 is configured as the second contact surface 22 of the movable guide rod. Rotating shaft cavities 12, equal in number to the number of the aforementioned movable guide rods 2 and spaced apart from each other, are formed along the length direction of the aforementioned rotating shaft 1. Figure 1 (Illustrated), on the cavity wall of the rotating shaft cavity 12 on the opposite side and at corresponding positions, there is a recessed part in the cavity wall, which forms the aforementioned sliding groove 11. The left and right ends of the aforementioned limiting shaft 4 are respectively slidably engaged with the aforementioned sliding groove 11.
[0028] Depend on Figure 1As shown, a moving guide rod arc transition flange clearance groove 121 is formed on the bottom wall of the aforementioned rotating shaft cavity 12 and at the center of the bottom wall. A moving guide rod arc transition flange 23 is formed at the end of the aforementioned moving guide rod 2 facing the aforementioned rotating shaft cavity 12 and located below the aforementioned moving guide rod first contact surface 21. The moving guide rod arc transition flange 23 corresponds to the aforementioned moving guide rod arc transition flange clearance groove 121.
[0029] In this embodiment, the aforementioned groove 11 is trapezoidal in shape, wider at the top and narrower at the bottom; the cross-sectional shape of the aforementioned moving guide rod arc transition flange clearance groove 121 is... The shape is shaped like a character, and the width is adapted to the thickness of the aforementioned moving guide rod 2.
[0030] Please see Figures 5 to 8 , Figure 5 The state shown is the closed position. Since the aforementioned moving guide rod 2 has a first contact surface 21 and a second contact surface 22, in the closed state, the first contact surface 21 is located below the limiting shaft 4, with a certain distance between them. Of course, it is also feasible to arrange the first contact surface 21 and the limiting shaft 4 to be in contact. Figure 5 As shown, in the closed state, the first contact surface 21 of the moving guide rod and the limiting shaft 4 are not in contact. During the opening process of the moving guide rod 2, as the moving guide rod 2 rotates, the first contact surface 21 of the moving guide rod comes into contact with the limiting shaft 4. The first contact surface 21 of the moving guide rod provides a thrust to the limiting shaft 4, pushing the limiting shaft 4 to move within the slide groove 11. The limiting shaft 4 correspondingly provides the moving guide rod 2 with a first torque to rotate in the closing direction until the moving guide rod 2 disengages from the obstruction of the limiting shaft 4 and forms a closed position. Figure 6 The state shown is equivalent to the position where the limiting shaft 4 passes between the first contact surface 21 and the second contact surface 22 of the moving guide rod (i.e., the dead point). The moving guide rod 2 continues to rotate clockwise under the action of electrodynamic force until it reaches the maximum repulsion position, thus exhibiting... Figure 7 The state shown is as follows. When the electrodynamic force on the moving guide rod 2 weakens, the moving guide rod 2 rotates counterclockwise towards the contact closing direction. The limiting shaft 4 contacts the second contact surface 22 of the moving guide rod 2, preventing the moving guide rod 2 from continuing to rotate. At this time, the limiting shaft 4 correspondingly applies a second torque to the moving guide rod 2 in the repulsive direction, wherein the first torque and the second torque are in opposite directions. The moving guide rod 2 eventually stops at the state shown. Figure 8 The repulsion position is shown.
[0031] In summary, the technical solution provided by this utility model makes up for the shortcomings of the prior art, successfully completes the invention task, and faithfully realizes the technical effects described by the applicant in the above technical effect column.
Claims
1. A moving contact structure comprising a rotating shaft (1), a moving guide rod (2) and a torsion spring (3), the moving guide rod (2) being pivotally arranged on the rotating shaft (1) at one end thereof towards the rotating shaft (1) by means of a moving guide rod pivot shaft (5), and the end of the moving guide rod (2) remote from the rotating shaft (1) being formed as a free end, the torsion spring (3) being arranged on the moving guide rod pivot shaft (5), characterized in that: Further comprising a limiting shaft (4) located on the rotating path of the moving guide rod (2) and slidingly arranged in a sliding groove (11) formed on the rotating shaft (1), the torsion spring (3) abuts against the limiting shaft (4) at one end of the sliding groove (11), and the torsion spring (3) abuts against the moving guide rod (2) at the other end of the moving guide rod (2); the moving guide rod (2) has a moving guide rod first contact surface (21) and a moving guide rod second contact surface (22), during repulsion of the moving guide rod (2), the moving guide rod (2) rotates clockwise, when the moving guide rod first contact surface (21) contacts the limiting shaft (4) and pushes the limiting shaft (4) to slide along the sliding groove (11) so that the moving guide rod (2) is separated from the stop of the limiting shaft (4) to reach the maximum repulsion position, at this time, if the moving guide rod (2) rotates counterclockwise, the limiting shaft (4) contacts the moving guide rod second contact surface (22) so that the moving guide rod (2) is kept at the repulsion position. 2. A moving contact structure according to claim 1, characterized in that: The torsion spring (3) arranged on the moving guide rod pivot shaft (5) is a double helix torsion spring, and is provided with a pair of corresponding limit shaft abutting feet (31) at one end, and is provided with a The shape of the character is shaped and abuts against the moving guide rod abutting foot (32) in a sleeved state on the moving guide rod (2). The pair of limit shaft abutting feet (31) abut against the upward side of the limit shaft (4) slidably arranged in the sliding groove (11), and the moving guide rod abutting foot (32) abuts against the end of the moving guide rod (2) toward the rotating shaft (1) and abuts against the downward side of the moving guide rod (2).
3. A moving contact structure according to claim 2, characterized in that: The moving guide rod abutting foot (32) abuts against the upper side of the moving guide rod (2) in the form of a saddle.
4. A moving contact structure according to claim 1 or 2, characterized in that: The rotating shaft (1) is provided with rotating shaft cavities (12) equal in number to the moving guide rods (2) and spaced apart in the length direction of the rotating shaft (1), on the cavity wall of the opposite side of the rotating shaft cavity (12) and at the corresponding positions, a recessed portion recessed from the cavity wall is formed, and the sliding groove (11) is formed by the recessed portion, the left end and the right end of the limiting shaft (4) are respectively slidingly matched with the sliding groove (11).
5. A moving contact structure according to claim 4, characterized in that: A moving guide rod arc surface transition flange avoiding groove (121) is formed on the cavity bottom wall of the rotating shaft cavity (12) and at the central position of the cavity bottom wall, a moving guide rod arc surface transition flange (23) is formed at the end of the moving guide rod (2) facing the rotating shaft cavity (12) and below the moving guide rod first contact surface (21), and the moving guide rod arc surface transition flange (23) corresponds to the moving guide rod arc surface transition flange avoiding groove (121).
6. A moving contact structure according to claim 4, characterized in that: The sliding groove (11) is in the shape of a trapezoid with wide upper part and narrow lower part.
7. A moving contact structure according to claim 5, characterized in that: The cross-sectional shape of the moving guide rod arc surface transition flange relief groove (121) is a rectangle, and the width is adapted to the thickness of the moving guide rod (2). The cross-sectional shape of the moving guide rod arc surface transition flange relief groove (121) is a rectangle, and the width is adapted to the thickness of the moving guide rod (2).