An operating mechanism for a circuit breaker

Abstract

An operating mechanism for a circuit breaker, belonging to the field of switchgear technology, includes a bracket, a trip latch, and a locking latch. A handle lever is oscillatingly mounted on the bracket. The trip latch and locking latch are rotatably mounted on the bracket, and they engage in a locking engagement. The trip latch has a locking engagement portion, characterized in that the locking engagement portion includes a straight engagement portion and a curved engagement portion. The length of the curved engagement portion is greater than or equal to 50% of the length of the locking engagement portion. When the circuit breaker is in the closed or open position, the engagement position of the trip latch and the locking latch is located on the straight engagement portion. When the circuit breaker is tripped, the locking latch rotates, and the engagement position of the trip latch and the locking latch moves from the straight engagement portion to the curved engagement portion until it disengages from the curved engagement portion, completing the tripping action. Advantages: It can prevent the circuit breaker from self-locking when tripping in the open position, ensuring the reliability of the circuit breaker's closing and opening tripping functions, and improving the stability of the operating mechanism.

Description

Technical Field

[0001] This utility model belongs to the field of switchgear technology, specifically relating to an operating mechanism for a circuit breaker. Background Technology

[0002] As is known in the industry, the operating mechanism is the core of the circuit breaker's drive. Through a series of mechanical actions such as energy storage, closing holding, rapid opening, and free tripping, it ensures that the circuit breaker can reliably perform circuit switching control and fault protection.

[0003] With the large-scale construction and planning of new energy systems such as photovoltaics, wind power, energy storage, and rail transit, DC power transmission and distribution systems have ushered in a golden age of rapid development. This is because these systems are essentially DC systems, while traditional power grids are AC systems. To connect these DC systems and integrate them into the power grid more efficiently, economically, and reliably, DC power transmission and distribution technology has become the most natural and optimized choice. Furthermore, the proposed "dual carbon" targets will further accelerate the energy structure transformation, with renewable energy becoming the mainstay. Circuit breakers used for AC and DC power distribution protection require higher mechanical lifespan and greater stability of their operating mechanisms. The circuit breaker's trip mechanism, as part of the operating mechanism, is mainly used to cooperate with door latches, linkages, etc., to complete a series of operations such as closing, opening, and tripping of the circuit breaker.

[0004] In AC high-voltage and DC high-voltage applications, the operating mechanism of existing circuit breakers is generally designed with a planar contact surface between the trip latch and the door lock latch. As a result, the operating mechanism has the problem of unreliable tripping in the open position. During the tripping operation of the operating mechanism in the open position, the lever arm of the interaction force between the trip latch and the door lock latch gradually decreases, and the unlocking torque provided by the trip latch to the door lock also gradually decreases, while the reset torque of the door lock return spring gradually increases. Therefore, when the unlocking torque is less than the reset torque of the door lock return spring, the trip latch and the door lock latch are prone to self-locking, resulting in unlocking failure. Utility Model Content

[0005] The purpose of this invention is to provide an operating mechanism for a circuit breaker to prevent the circuit breaker from tripping or the latch from self-locking when it is in the open position.

[0006] The present invention accomplishes its objective as follows: A circuit breaker operating mechanism includes a bracket, a trip latch, and a locking latch. A handle lever is oscillatingly mounted on the bracket. The trip latch and locking latch are rotatably mounted on the bracket, and they overlap. A locking latch overlap portion is provided on the trip latch. The locking latch overlap portion comprises a straight overlap portion and a curved overlap portion. The length of the curved overlap portion is greater than or equal to 50% of the length of the locking latch overlap portion. When the circuit breaker is in the closed or open position, the overlap position of the trip latch and the locking latch is located on the straight overlap portion. When the circuit breaker is tripped, the locking latch rotates, and the overlap position of the trip latch and the locking latch moves from the straight overlap portion to the curved overlap portion until it disengages from the curved overlap portion, completing the tripping action.

[0007] Furthermore, the curved overlapping portion is located at one end of the extension of the straight overlapping portion and away from the rotation center of the buckle.

[0008] Furthermore, the overlapping part of the curved surface is a curved surface or an arc surface.

[0009] Furthermore, the curved or arcuate surface is in external tangential contact with the latching point.

[0010] Furthermore, the operating mechanism of the circuit breaker also includes a linkage assembly, which includes a first linkage, a second linkage, and a hinge shaft. One end of the first linkage is hinged to the main shaft of the operating mechanism's structural system, and the other end is hinged to one end of the second linkage via the hinge shaft. The other end of the second linkage is hinged to the trip latch, which has a closing limit part. When the circuit breaker is closed, the closing limit part and the hinge shaft abut against each other to form an inscribed circle tangential fit.

[0011] Furthermore, the closing limit part is a curved surface.

[0012] The technical solution provided by this utility model is that the trip latch is provided with a straight overlapping part and a curved overlapping part on the latch overlap part, so that the force between the trip latch and the latch changes when the trip latch and the latch are released in the open position. Therefore, it can prevent the circuit breaker from self-locking when it is released in the open position, ensure the reliability of the circuit breaker's opening and closing tripping function, and improve the stability of the operating mechanism. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the present invention in the closed state; Figure 2 for Figure 1 Enlarged view of part A; Figure 3 This is a schematic diagram of the present invention in the open state; Figure 4 for Figure 3 Enlarged view of part B; Figure 5 This is a schematic diagram of the present invention moving from the open state to the tripped state to the curved section; Figure 6 for Figure 5 Enlarged view of part C; Figure 7 for Figure 1 Enlarged view of part D.

[0014] In the diagram: 1. Bracket; 2. Jumper; 21. Locking overlap; 211. Straight overlap; 212. Curved overlap; 22. Closing limit; 3. Lock; 4. Linkage assembly; 41. First link; 42. Second link; 43. Hinge shaft; 5. Handle lever; 6. Return spring; 10. Main shaft. Detailed Implementation

[0015] Based on professional knowledge, a circuit breaker includes a housing, an operating mechanism, and a main shaft 10 ( Figure 1 and Figure 4 The circuit breaker is shown in the diagram. The contact system includes a moving contact and a stationary contact. The operating mechanism of this invention is installed on the aforementioned housing. The main shaft 10 is rotatably disposed inside the housing. The moving contact is installed inside the main shaft 10, while the stationary contact is installed on the housing. The moving contact and the stationary contact are in contact and cooperate to realize the closing and opening of the circuit breaker.

[0016] Since the operating mechanism is the driving core of the circuit breaker, it is an energy component used to drive the movement of the main shaft 10. When the main shaft 10 is driven, the main shaft 10 drives the moving contact inside it to move, thereby enabling the moving contact to make contact or separate from the stationary contact.

[0017] Circuit breakers also include a tripped state and a re-tripped state. The tripped state refers to the state in which the circuit breaker automatically breaks when it encounters a fault current during operation. In the tripped state, in order for the circuit breaker to return to the reclosable state, the handle needs to be operated to cause the operating mechanism to perform a re-tripping action, thus entering the re-tripped state.

[0018] Please see Figures 1 to 7 The diagram shows the support 1, the jumper 2, the lock 3, the linkage assembly 4, the handle lever 5, and the return spring 6 of the operating mechanism.

[0019] Specifically, the aforementioned bracket 1 is a metal frame, which serves as the base for mounting and positioning other components of the operating mechanism; the aforementioned handle lever 5 is oscillatingly mounted on the aforementioned bracket 1; the aforementioned jump buckle 2 and lock buckle 3 are rotatably mounted on the aforementioned bracket 1; one end of the aforementioned linkage assembly 4 abuts against the jump buckle 2, and the other end is hinged to the aforementioned main shaft 10. The aforementioned linkage assembly 4 consists of two linkages that are hinged together by a hinge shaft.

[0020] Specifically, the linkage assembly 4 includes a first link 41, a second link 42, and a hinge shaft 43. The first link 41 and the second link 42 are hinged together via the hinge shaft 43. One end of the first link 41 is hinged to the main shaft 10, and the other end of the first link 41 is hinged to one end of the second link 42 via the hinge shaft 43. The other end of the second link 42 is hinged to the jump buckle 2, and the second link 42 can rotate with the jump buckle 2.

[0021] The aforementioned handle lever 5 is typically a machined part made of a metal sheet. It is usually manufactured by bending and stamping.

[0022] The aforementioned trip latch 2 and latch 3 engage in a locking mechanism, with the trip latch 2 having a closing limit part 22. A latch engagement part 21 is provided at the end of the trip latch 2. This latch engagement part 21 includes a straight engagement part 211 and a curved engagement part 212. The straight engagement part 211 is located near the rotation center of the aforementioned trip latch, while the curved engagement part 212 is located at one end of the extension of the straight engagement part 211 and away from the rotation center of the trip latch 2. The length of the curved engagement part 212 is greater than 50% of the length of the latch engagement part 21, and the curved engagement part 212 is a curved surface or an arc surface. The curved surface or arc surface has external tangential contact with the engagement point of the latch 3, effectively increasing the unlocking torque of the trip latch during the latter half of its relative movement during the tripping process, ensuring reliable tripping and preventing self-locking. The applicant should note that it is also possible to design the length of the aforementioned curved overlapping portion 212 to be equal to the length of the locking overlapping portion 21.

[0023] When the circuit breaker is in the closed position, the closing limit part 22 collides with the hinge shaft 43. The closing limit part 22 is an arc surface, and the contact point between the two is the point where their inner circles are tangent. In other words, when the circuit breaker is closed, the closing limit part 22 and the hinge shaft 43 form a tangent inner circle fit relationship, which can reduce the contact stress at the closing limit position and improve the mechanical life of the circuit breaker.

[0024] When the circuit breaker is in the closed or open position, the contact position of the trip latch 2 and the latch 3 is located at the straight contact portion 211. When the circuit breaker trips, the traction rod of the operating mechanism is unlocked, the trip latch 2 rotates, and the latch 3 rotates against the friction and spring force. The contact position gradually moves from the straight contact portion 211 to the curved contact portion 212 until it disengages from the curved contact portion 212 and finally completes the tripping action.

[0025] When the latch is repositioned, the overlap position of the latch 2 and the lock 3 is located at the straight overlap portion 211. During the disengagement process, as the latch 2 and the lock 3 rotate, the contact point gradually moves away from the rotation center of the latch. The lever arm of the interaction force between the latch and the lock on the lock 3 gradually decreases, and the unlocking torque provided by the latch 2 to the lock 3 also gradually decreases, while the restoring torque of the return spring 6 gradually increases. When the contact position moves to the curved overlap portion 212, due to the change in the direction of the force, the unlocking torque provided by the latch 2 to the lock 3 gradually increases, ensuring that the unlocking torque is always greater than the restoring torque of the return spring, thus guaranteeing reliable disengagement and preventing self-locking.

[0026] Specifically, during the circuit breaker tripping process, latch 3 is subjected to three torques: torque M3 provided by the return spring 6; torque M1 generated by the interaction force between the tripping and latching; and torque M2 generated by the frictional force between tripping latch 2 and latch 3. M1 is the unlocking torque, which facilitates the movement of latch 3 in the tripping direction; M1 and M2 inhibit the movement of latch 3 in the tripping direction. To ensure reliable circuit breaker tripping, it is necessary to ensure that the latch remains in the tripping direction throughout the entire tripping process.

[0027] Where F1 is the force exerted by the jump buckle 2 on the lock buckle 3, and its direction is the normal direction of the jump buckle's overlapping surface; L1 is the lever arm of F1 relative to the rotation center of the lock buckle 3; M3 is the torque provided by the return spring 6 to the lock buckle 3; where F2 is the frictional force provided by the jump buckle 2 to the lock buckle 3, and its direction is along the tangential direction of the jump buckle's overlapping surface; L2 is the lever arm of F2 relative to the rotation center of the lock buckle 3.

[0028] After the tripping process begins, latch 3 rotates around the rotation center in the tripping direction, and the contact point of the jump latch gradually moves away from the rotation center of the jump latch along the straight segment of the overlapping surface. L1 decreases; M3 increases; L2 increases, that is, M1 decreases and M3+M2 increases. When the overlapping point moves to a point where it can no longer satisfy formula (1), latch 3 is prone to self-locking, and tripping fails. Therefore, the rear segment of the overlapping surface is set as a curved surface or an arc surface. Before latch 3 self-locks, the overlapping point moves from the straight segment to the arc segment. At this time, the directions of F1 and F2 are offset, and the corresponding L1 and L2 change. As the overlapping point moves along the curved surface or arc surface, L1 increases and L2 decreases, keeping formula (1) satisfied throughout the tripping process, which can ensure reliable tripping and avoid self-locking.

[0029] It should be noted that the shape of the latching surface is not necessarily a combination of a straight section and a curved section; it can also be a single curved section or an arc section; or a straight section plus a sloping section at a different angle, etc. As long as it is ensured that during the disengagement process, compared to a conventional straight section latching surface, the torque exerted by the latching surface on the door lock tends to increase as the latching point moves, it is acceptable.

Claims

1. An operating mechanism for a circuit breaker, comprising a bracket (1), a trip latch (2), and a locking latch (3); a handle lever (5) is oscillatingly mounted on the bracket (1), the trip latch (2) and the locking latch (3) are respectively rotatably mounted on the bracket (1), the trip latch (2) and the locking latch (3) are engaged, and a locking latch engagement portion (21) is provided on the trip latch (2), characterized in that: The latching overlap portion (21) includes a straight overlap portion (211) and a curved overlap portion (212). The length of the curved overlap portion (212) is greater than or equal to 50% of the length of the latching overlap portion (21). When the circuit breaker is in the closed or open position, the overlap position of the trip latch (2) and the latch (3) is located on the straight overlap portion (211). When the circuit breaker is tripped, the latch (3) rotates, and the overlap position of the trip latch (2) and the latch (3) moves from the straight overlap portion (211) to the curved overlap portion (212) until it disengages from the curved overlap portion (212) to complete the tripping action.

2. The operating mechanism of a circuit breaker according to claim 1, characterized in that: The curved surface overlap (212) is located at one end of the extension of the straight surface overlap (211) and away from the rotation center of the jump buckle (2).

3. The operating mechanism of a circuit breaker according to claim 1 or 2, characterized in that: The curved surface overlap (212) is a curved surface or a circular arc surface.

4. The operating mechanism of a circuit breaker according to claim 3, characterized in that: The curved or arc-shaped surface is in external tangential contact with the latch (3) at the point of contact.

5. The operating mechanism of a circuit breaker according to claim 1, characterized in that: The operating mechanism of the circuit breaker also includes a linkage assembly (4), which includes a first linkage (41), a second linkage (42), and a hinge shaft (43). One end of the first linkage (41) is hinged to the main shaft (10) of the structure system of the operating mechanism, and the other end is hinged to one end of the second linkage (42) through the hinge shaft (43). The other end of the second linkage (42) is hinged to the trip latch (2). The trip latch (2) has a closing limit part (22). When the circuit breaker is closed, the closing limit part (22) and the hinge shaft (43) abut against each other to form an inscribed circle tangential fit.

6. The operating mechanism of a circuit breaker according to claim 5, characterized in that: The closing limit part (22) is a curved surface.

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