A miniature circuit breaker

Abstract

The application relates to the field of circuit breakers, and particularly discloses a miniature circuit breaker which comprises a shell, a static contact arranged in the shell, a three-link mechanism and a protection execution mechanism; the three-link mechanism comprises a handle, a moving contact, a connecting rod and a connecting rod tension spring; the protection execution mechanism is movable and used for limiting the rotation of the connecting rod; the protection execution mechanism can release the rotation limitation of the connecting rod when the circuit is overloaded or short-circuited; a limiting block is arranged in the shell; when the limiting block is in contact with the connecting rod, the connecting rod tension spring is located on the side of the hinged joint between the moving contact and the handle which is away from the static contact; when the circuit breaker is closed, the connecting rod tension spring is located on the side of the hinged joint between the moving contact and the handle which is close to the static contact; and when the circuit breaker is opened, the connecting rod tension spring is located on the side of the hinged joint between the moving contact and the handle which is away from the static contact. The application has the effects of simplifying the structure of the circuit breaker and improving the performance stability of the circuit breaker.

Description

Technical Field

[0001] This application relates to the field of circuit breakers, and more particularly to a miniature circuit breaker. Background Technology

[0002] Miniature circuit breakers are automatic switching devices used for overload and short-circuit protection in low-voltage power distribution systems. They can be manually reset after tripping.

[0003] Existing circuit breakers use a five-bar linkage mechanism, which is complex, leading to numerous manufacturing processes, difficult assembly, and high product costs. The complex structure also affects the stability of product performance; circuit breakers using the five-bar linkage mechanism can exhibit performance variations even under different installation conditions, often requiring extensive post-installation calibration. Summary of the Invention

[0004] To simplify the circuit breaker structure and improve its performance stability, this application provides a miniature circuit breaker.

[0005] The miniature circuit breaker provided in this application adopts the following technical solution:

[0006] A miniature circuit breaker includes a housing and stationary contacts disposed within the housing, as well as a three-bar linkage and a protection actuator.

[0007] The three-bar linkage includes:

[0008] Handle: Rotary setting on the housing;

[0009] Moving contact: hinged to the handle;

[0010] Linkage member: Rotatably mounted inside the housing and used to drive the moving contact to rotate and open the circuit breaker;

[0011] Linkage spring: The two force-applying ends are respectively connected to the link and the moving contact. It is used to drive the link to rotate so as to push the moving contact to rotate and open the circuit. It is also used to drive the moving contact to rotate.

[0012] The protective actuator is movable and used to restrict the rotation of the connecting rod. The protective actuator can release the rotation restriction on the connecting rod when the circuit is overloaded or short-circuited. A limit block is provided inside the housing. The limit block is located on the rotation path of the connecting rod and is used to restrict the rotation of the connecting rod. When the limit block abuts against the connecting rod, the connecting rod tension spring is located on the side away from the stationary contact at the hinge point between the moving contact and the handle.

[0013] When the circuit is closed, the connecting rod spring is located on the side of the hinge point between the moving contact and the handle that is closer to the stationary contact; when the circuit is opened, the connecting rod spring is located on the side of the hinge point between the moving contact and the handle that is farther away from the stationary contact.

[0014] When the tripping begins:

[0015]

[0016]

[0017]

[0018]

[0019] F1 is the tension spring force of the connecting rod, and F2 is the thrust of the connecting rod on the moving contact.

[0020] L1 is the lever arm of F1 on the connecting rod, and L2 is the lever arm of F2 on the connecting rod;

[0021] L3 is the lever arm of F1 on the moving contact, and L4 is the lever arm of F2 on the moving contact.

[0022] By adopting the above technical solution, when an overload or short circuit occurs in the circuit, the protection actuator releases the rotation restriction on the connecting rod. Under the action of the connecting rod tension spring, the connecting rod rotates and strikes the moving contact. Because...

[0023]

[0024]

[0025]

[0026]

[0027] but

[0028]

[0029]

[0030] The force exerted on the moving contact by the connecting rod tension spring is less than the torque exerted on the moving contact by the connecting rod.

[0031] Therefore, the connecting rod can drive the moving contact to rotate. Once the moving contact rotates to the point where the connecting rod spring is located away from the stationary contact at the hinge point between the moving contact and the handle, the connecting rod spring applies a force to the moving contact to drive it to open, accelerating the opening of the moving contact. During this process, the connecting rod abuts against the limit block to restrict further rotation of the connecting rod under the force of the connecting rod spring. At this point, the connection point between the connecting rod spring and the connecting rod can be considered a fixed point, meaning that the connecting rod spring only applies a force to the moving contact to drive it to open.

[0032] When closing the circuit, the reverse handle resets, and the handle drives the moving contact to reverse. During this process, the connecting rod spring gradually stretches and stores energy until the connecting rod spring is located on the side of the hinge point between the moving contact and the handle that is close to the stationary contact. At this time, the connecting rod spring releases energy and drives the moving contact to accelerate the closing process until it contacts the stationary contact.

[0033] This application simplifies the linkage mechanism to a three-bar linkage. Through the setting of the lever arm, it realizes the opening and closing of the circuit breaker using the three-bar linkage, enabling rapid opening and closing. This simplifies the circuit breaker structure, effectively reduces the impact of component precision on the product, and improves the performance stability of the circuit breaker. Existing circuit breakers often rely solely on manual operation for closing; this application achieves rapid closing through a linkage spring, greatly improving the safety performance of the circuit breaker.

[0034] Optionally, the handle is provided with a reset block, and the connecting rod is located on the rotation path of the reset block. When the circuit is opened, the reset block is used to push the connecting rod to rotate and reset until the protection actuator can re-limit the rotation of the connecting rod.

[0035] By adopting the above technical solution, when the circuit breaker is opened, the protection actuator releases the restriction on the connecting rod, and the connecting rod rotates until it contacts the limit block. The rotating moving contact drives the handle to rotate, and the reset block rotates together with the handle. During the rotation, the reset block contacts the connecting rod and pushes the connecting rod to reverse and reset, and the protection actuator re-limits the rotation of the connecting rod. With this configuration, the connecting rod can also be reset by the force applied by the connecting rod tension spring when the circuit breaker is opened, without the need for separate reset. Moreover, the reset can be achieved during opening, ensuring that the short-circuit protection and overload protection functions can function before closing, thus ensuring the safety of the circuit breaker.

[0036] Optionally, the moving contact is provided with a flipping concave arc surface for contacting the connecting rod.

[0037] By adopting the above technical solution, when the circuit breaker is opened, the connecting rod rotates and presses against the flipping concave arc surface. Compared with the plane surface where the moving contact contacts the connecting rod, the moving contact rotates around its hinge point with the handle. The flipping concave arc surface guides the rotation of the moving contact, accelerating the rotation of the moving contact relative to the handle. This achieves the effect of quickly throwing the contact point between the moving contact and the stationary contact away from the stationary contact, which further improves the opening speed and the breaking capacity of the circuit breaker in this application.

[0038] Optionally, the protection actuator includes a latch rotatably disposed within the housing, a protection actuator component for driving the latch to rotate, and a reset elastic element for driving the latch to reset. The latch has a locking groove for inserting the end of the connecting rod. When the circuit is overloaded or short-circuited, the protection actuator component drives the latch to rotate until the end of the connecting rod moves out of the locking groove.

[0039] By adopting the above technical solution, during circuit breaking, the protection actuator drives the latch to rotate, the end of the connecting rod moves out of the locking groove, and under the action of the connecting rod tension spring, rotates rapidly, causing the moving contact to open and breaking the circuit. Rotating the handle pushes the connecting rod back to the locking groove via the reset block, and the reset elastic element drives the latch to reset, allowing the end of the connecting rod to insert into the locking groove. The latch locks and unlocks by rotation and is reset by the reset elastic element, requiring no additional operation and featuring a reliable and simple structure.

[0040] Optionally, the protection actuator includes a movable armature rotatably disposed within the housing, and the latch is provided with a short-circuit trigger. When the circuit is short-circuited, the movable armature can rotate to abut against the short-circuit trigger and cause the latch to rotate until the end of the connecting rod moves out of the locking groove.

[0041] By adopting the above technical solution, when a short circuit occurs, the moving armature rotates and presses against the short-circuit trigger to cause the latch to rotate. Once the latch rotates to the point where the wall of the locking groove no longer contacts the connecting rod, the connecting rod rotates and causes the moving contact to rotate and open the circuit. Compared to short-circuit protection using a traditional electromagnetic coil tripping mechanism, the use of a moving armature significantly reduces the number of parts in the tripping mechanism, lowering product costs and assembly difficulty.

[0042] Optionally, the reset elastic element is a torsion spring, and the two force-applying ends of the reset elastic element apply force to the latch and the moving armature respectively and are used to reset the latch and the moving armature.

[0043] By adopting the above technical solution, when the latch rotates to unlock the connecting rod and when the circuit short-circuit causes the moving armature to rotate, the reset elastic element deforms and stores energy. After the connecting rod separates from the latch, the latch is reset, and after the circuit returns to normal, the moving armature is reset. Both the connecting rod and the moving armature can be reset by using the reset elastic element, resulting in a compact structure.

[0044] Optionally, the latch is provided with a plurality of adjusting blocks, each of which is used to abut against the force-applying end of the reset elastic element.

[0045] By adopting the above technical solution, by adjusting one of the force-applying ends of the reset elastic element to abut against different adjustment blocks, the compression amount of the reset elastic element can be adjusted, that is, the force applied by the reset elastic element to the latch can be adjusted, thereby changing the force required to push the latch to rotate, so as to meet different triggering requirements and improve adaptability.

[0046] Optionally, the latch is provided with an overload trigger, and the protection actuator includes a bimetallic strip for overload protection. When the circuit is overloaded, the bimetallic strip can deform to abut against the overload trigger and cause the latch to rotate until the end of the connecting rod moves out of the locking groove.

[0047] By adopting the above technical solution, compared with setting up a complex linkage mechanism to directly cooperate with the bimetallic strip to achieve overload protection, the overload trigger on the latch is linked with the bimetallic strip, so that when the circuit is overloaded, the bimetallic strip can deform and drive the latch to rotate through the overload trigger, so that the latch rotates to the end of the linkage and moves out of the locking groove. This setting further simplifies the structure, and the short circuit and overload protection functions are integrated on the latch.

[0048] Optionally, it also includes an input terminal, the protection actuator includes a protection actuation component, the protection actuation component includes a bimetallic strip for overload protection, and the input terminal is electrically connected to the stationary contact via the bimetallic strip.

[0049] By adopting the above technical solution, the internal circuit length of the circuit breaker is greatly shortened by using the bimetallic strip directly as the circuit, which not only reduces the cost but also the resistance, thereby effectively reducing the power consumption and temperature rise of the circuit breaker in this application.

[0050] Optionally, a linkage plug is provided on one side of the latch along its own rotation direction, and a linkage seat is provided on the other side of the latch along its own rotation direction. A linkage slot is provided on the linkage seat. The linkage plug and / or linkage seat extends through the housing. When multiple miniature circuit breakers are combined, the linkage plug of one miniature circuit breaker is used to insert into the linkage slot of the adjacent miniature circuit breaker.

[0051] By adopting the above technical solution, when multiple miniature circuit breakers of this application are used in a group, the linkage plugs and linkage slots of adjacent miniature circuit breakers cooperate with each other so that when a short circuit or overload occurs, the latches of each miniature circuit breaker can be rotated and unlocked at the same time, so that the linkages of each miniature circuit breaker can be rotated together, and finally the moving contacts of each miniature circuit breaker can be rotated together to open the circuit.

[0052] In summary, this application includes at least one of the following beneficial technical effects:

[0053] 1. By setting a three-bar linkage and a suitable lever arm, this application can realize opening and closing through the three-bar linkage, and can realize fast opening and fast closing, which greatly simplifies the circuit breaker structure, not only reducing costs, but also improving the performance stability of the circuit breaker of this application.

[0054] 2. The reset block setting enables the connecting rod to be reset during the tripping process of the circuit breaker in this application, without the need for manual reset;

[0055] 3. The moving armature for short-circuit protection and the bimetallic strip for overload protection are integrated together by a latch. Both short circuits and overloads are triggered by the latch. Compared with traditional electromagnetic tripping mechanisms and thermal tripping mechanisms, this significantly reduces the number of parts and lowers product costs. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the structure when the circuit is closed according to an embodiment of this application.

[0057] Figure 2 This is a structural schematic diagram highlighting the connecting rod, handle, and moving contact in the embodiments of this application.

[0058] Figure 3 This is a cross-sectional schematic diagram of the circuit breaker tripping process in an embodiment of this application.

[0059] Figure 4 yes Figure 1 An enlarged schematic diagram showing the force analysis after removing the connecting rod tension spring at point A.

[0060] Figure 5 This is a schematic diagram of the structure of removing the connecting rod tension spring when the circuit is fully opened according to the embodiment of this application.

[0061] Figure 6 This is a schematic diagram highlighting the structure of the protection actuator in the embodiments of this application.

[0062] Explanation of reference numerals in the attached figures:

[0063] 1. Housing; 11. Limiting block; 2. Stationary contact; 3. Three-bar linkage; 31. Handle; 311. Reset support block; 32. Moving contact; 321. Flipping concave arc surface; 33. Linkage member; 331. Rotating seat; 332. Locking linkage part; 333. Reset linkage part; 334. Trigger part; 34. Linkage spring; 4. Protection actuator; 41. Lock; 411. Linkage insert; 412. Linkage seat; 4121. Linkage slot; 413. Locking slot; 414. Reset head; 415. Short circuit trigger; 416. Adjusting block; 417. Overload trigger; 42. Reset elastic element; 43. Protection actuator assembly; 431. Moving armature; 432. Bimetallic strip; 5. Arc extinguishing chamber; 6. Incoming terminal; 7. Outgoing terminal. Detailed Implementation

[0064] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0065] This application discloses a miniature circuit breaker. (Refer to...) Figure 1 The miniature circuit breaker includes a housing 1, a stationary contact 2 fixed inside the housing 1, a three-bar linkage 3 for opening and closing the circuit, a protection actuator 4 for circuit protection, and an arc-extinguishing chamber 5 for arc extinguishing.

[0066] Reference Figure 1The housing 1 has an inlet terminal 6 and an outlet terminal 7 located at both ends of the housing 1. The stationary contact 2, the three-bar linkage 3, the protection actuator 4, and the arc-extinguishing chamber 5 are all located between the inlet terminal 6 and the outlet terminal 7. The arc-extinguishing chamber 5 is installed inside the housing 1 and is located on one side of the stationary contact 2.

[0067] Reference Figure 1 The three-bar linkage 3 includes a handle 31, a moving contact 32 for opening and closing the circuit breaker, a connecting rod 33 for driving the moving contact 32 to rotate and open the circuit breaker, and a connecting rod tension spring 34 for applying force to the moving contact 32 and the connecting rod 33.

[0068] Reference Figure 1 , Figure 2 The handle 31 is rotatably mounted on the housing 1, with one end extending outside the housing 1 for rotation operation. The moving contact 32 is electrically connected to the outgoing terminal 7 via a flexible connection. One end of the moving contact 32 is hinged to the handle 31, and this hinge point is offset from the rotation axis of the handle 31 itself. The surface of the moving contact 32 that contacts the connecting rod 33 is a flipped concave arc surface 321. When the moving contact 32 abuts against the stationary contact 2, the circuit is closed; when the moving contact 32 separates from the stationary contact 2, the circuit is opened.

[0069] Reference Figure 1 , Figure 2 The linkage 33 includes a rotating base 331, a locking linkage 332, a reset linkage 333, and a trigger 334. The rotating base 331 is rotatably disposed within the housing 1. One end of the reset linkage 333 is connected to the rotating base 331, and the other end extends toward the handle 31. One end of the locking linkage 332 is connected to the rotating base 331, and the other end extends toward the protection actuator 4. One end of the trigger 334 is connected to the rotating base 331, and the other end extends toward the moving contact 32 and is used to abut against the flipping concave surface 321 to push the moving contact 32 to rotate. The rotating base 331, the reset linkage 333, the locking linkage 332, and the trigger 334 are integrally formed.

[0070] Reference Figure 2 , Figure 3 The handle 31 has an integrally formed reset block 311. The ends of the reset block 311 and the reset linkage 333 extending toward the handle 31 are both hook-shaped. The end of the reset linkage extending toward the handle 31 is located on the rotation path of the reset block 311. When the circuit is opened, the reset block 311 can rotate to the side of the reset linkage 333 extending toward the handle 31, close to the moving contact 32, so as to apply force to the reset linkage 333 and cause the linkage 33 to rotate and reset.

[0071] Reference Figure 1 , Figure 2The two force-applying ends of the connecting rod tension spring 34 are respectively hooked into the holes on the moving contact 32 and the end of the reset linkage 333 extending towards the handle 31. On the one hand, it is used to apply a force to the connecting rod 33 to drive the reset linkage 333 in the direction of rotation of the moving contact of the moving contact 32, so as to push the moving contact 32 to rotate and open the circuit. On the other hand, it is used to apply a force to drive the moving contact 32 to rotate, so that the moving contact 32 can accelerate towards the stationary contact 2 during the closing process and accelerate away from the stationary contact 2 during the opening process.

[0072] Reference Figure 1 , Figure 3 A limiting block 11 is integrally formed inside the housing 1, which locks the rotation path of the linkage 332 and is used to abut against the side of the locking linkage 332 near the handle 31 to restrict the rotation of the connecting rod 33. When the locking linkage 332 abuts against the limiting block 11, the connecting rod tension spring 34 is located on the side away from the stationary contact 2 at the hinge point between the moving contact 32 and the handle 31.

[0073] Reference Figure 1 When closing, the connecting rod spring 34 is located on the side of the hinge point between the moving contact 32 and the handle 31 closer to the stationary contact 2; when opening, the connecting rod spring 34 is located on the side of the hinge point between the moving contact 32 and the handle 31 away from the stationary contact 2.

[0074] Reference Figure 1 , Figure 4 When the tripping begins:

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081] but

[0082]

[0083]

[0084] F1 is the tension spring force of the connecting rod, and F2 is the thrust of the connecting rod 33 on the moving contact 32;

[0085] L1 is the lever arm of F1 on the connecting rod 33, and L2 is the lever arm of F2 on the connecting rod 33;

[0086] L3 is the lever arm of F1 on the moving contact 32, and L4 is the lever arm of F2 on the moving contact 32;

[0087] By lever arm ratio, i.e. This ensures that the connecting rod 33 of this application can smoothly push the moving contact 32 to rotate and open the circuit breaker.

[0088] Reference Figure 5 , Figure 6 The protective actuator 4 is movable and can restrict the rotation of the connecting rod 33, or release the restriction on the rotation of the connecting rod 33. The protective actuator 4 includes a latch 41 rotatably disposed in the housing 1, a protective actuator assembly 43 for driving the latch 41 to rotate, and a reset elastic member 42 for driving the latch 41 to reset. The protective actuator assembly 43 includes a moving armature 431 for short-circuit protection and a bimetallic strip 432 for overload protection.

[0089] Reference Figure 6 The latch 41 has an integrally formed linkage insert 411 on one side along its own rotation direction, and a linkage seat 412 is provided on the other side along its own rotation direction. The linkage seat 412 has a linkage slot 4121. The linkage insert 411 and / or the linkage seat 412 extend through the outer shell 1. When multiple miniature circuit breakers are combined, the linkage insert 411 of one miniature circuit breaker is used to insert into the linkage slot 4121 of the adjacent miniature circuit breaker to realize the synchronous rotation of the latches 41 of each miniature circuit breaker.

[0090] Reference Figure 5 , Figure 6 The latch 41 has a locking groove 413 for inserting the end of the locking linkage 332 to restrict the rotation of the connecting rod 33. A reset head 414 is integrally formed on the latch 41, protruding beyond the direction of the connecting rod 33. The reset head 414 is located on the rotation path of the locking linkage 332. The end of the locking linkage 332 is a slope facing the rotation axis of the latch 41. When the latch 41 rotates and the locking linkage 332 moves out of the locking groove 413, the reset head 414 rotates with the latch 41 without interfering with the movement of the locking linkage 332. When the connecting rod 33 resets, the slope of the end of the locking linkage 332 presses against the reset head 414, and the reset head 414 pushes the latch 41 to rotate, allowing the locking linkage 332 to insert into the locking groove 413.

[0091] Reference Figure 5 , Figure 6The protection actuator 43 includes a bimetallic strip 432 for overload protection and a moving armature 431 for short-circuit protection. The moving armature 431 is rotatably mounted inside the housing 1. The cross-sectional shape of the moving armature 431 along the direction perpendicular to its own rotation axis is approximately cane-shaped, with its rotation axis located near the head. Its rod portion is used for the main attraction function. A short-circuit trigger 415 is integrally formed on the latch 41, and the short-circuit trigger 415 is eccentrically positioned. The head of the moving armature 431 is located on one side of the short-circuit trigger 415. When the circuit is short-circuited, the moving armature 431 can rotate to abut against the short-circuit trigger 415, causing the latch 41 to rotate until the end of the locking linkage 332 moves out of the locking groove 413.

[0092] Reference Figure 6 The latch 41 has multiple adjusting blocks 416 integrally formed on it. The reset elastic element 42 is a torsion spring. The force-applying end of the reset elastic element 42 is used to press against one side of the rod of the moving armature 431 and one of the adjusting blocks 416 to reset the latch 41 and the moving armature 431. By pressing one of the force-applying ends of the reset elastic element 42 against different adjusting blocks 416, the compression of the reset elastic element 42 can be adjusted.

[0093] Reference Figure 1 The bimetallic strip 432 is located on the side of the moving armature 431 near the arc-extinguishing chamber 5. One end of the bimetallic strip 432 is fixed to the stationary contact 2, and the other end of the bimetallic strip 432 is movable and electrically connected to the input terminal 6 via a flexible connection. Thus, a conductive circuit is formed through the input terminal 6, the bimetallic strip 432, the stationary contact 2, the moving contact 32, and the output terminal 7. An overload trigger 417 is integrally formed on the latch 41. The overload trigger 417 is rod-shaped and located on the deformation path of the movable end of the bimetallic strip 432. When the circuit is overloaded, the bimetallic strip 432 can deform to contact the overload trigger 417, causing the latch 41 to rotate until the end of the locking linkage part 332 moves out of the locking groove 413.

[0094] The implementation principle of a miniature circuit breaker according to an embodiment of this application is as follows: During tripping, there are two scenarios. When a short circuit occurs, a large current flows through the circuit, and the moving armature 431 is attracted towards the bimetallic strip 432. The rod of the moving armature 431 rotates towards the bimetallic strip 432, causing its head to rotate towards the short-circuit trigger 415, which in turn causes the latch 41 to rotate. When a circuit overload occurs, the circuit temperature rises, and the bimetallic strip 432 deforms due to heat and presses against the overload trigger 417, causing the latch 41 to rotate.

[0095] As the latch 41 rotates, the opening orientation of the locking groove 413 changes continuously until the groove wall of the locking groove 413 no longer restricts the end of the locking linkage 332. At this time, under the action of the connecting rod spring 34, the connecting rod 33 rotates, the end of the locking linkage 332 moves out of the locking groove 413, and the trigger part 334 presses against the flipping concave surface 321 to push the moving contact 32 to rotate and open the circuit. The moving contact 32 moves while flipping along the flipping concave surface 321, and at the same time pushes the handle 31 to rotate through its hinge point with the handle 31.

[0096] During the rotation of the connecting rod 33, the locking linkage 332 abuts against the limit block 11 to restrict the further rotation of the rod. On the one hand, this restricts the force of the connecting rod 33 from being applied to the handle 31, which affects the opening rotation of the handle 31 and thus the opening rotation of the moving contact 32. On the other hand, it helps the connecting rod tension spring 34 to apply a stable spring force to the moving contact 32.

[0097] During the rotation of the moving contact 32, the position of the connecting rod tension spring 34 changes from being located on the side of the hinge point between the moving contact 32 and the handle 31 closer to the stationary contact 2, to being located on the side of the hinge point between the moving contact 32 and the handle 31 farther away from the stationary contact 2, thereby realizing the accelerated opening of the moving contact 32.

[0098] During the rotation of the handle 31, the reset linkage block is lifted by the reset support block 311, so that the connecting rod 33 is reversed and reset. During the reset process, the inclined surface of the end of the locking linkage part 332 presses against the reset head 414, and the lock 41 is rotated by the reset head 414 until the end of the locking linkage part 332 is re-aligned with the locking groove 413 and inserted into the locking groove 413.

[0099] When closing the circuit, manually turn the handle 31 or turn the handle 31 by other means. During the rotation of the handle 31, the moving contact 32 will rotate to close the circuit. The connecting rod spring 34 will stretch and store energy until the relative position of the connecting rod spring 34 moves to the side of the hinge point between the moving contact 32 and the handle 31 that is close to the stationary contact 2. At this time, the connecting rod spring 34 will release energy and accelerate the closing to achieve fast closing.

[0100] The miniature circuit breaker of this application can achieve opening and closing through a three-bar linkage 3, and it is fast opening and closing. Overload protection and short circuit protection also achieve component simplification. The overall structure of the miniature circuit breaker is greatly simplified, effectively reducing product costs and improving performance stability.

[0101] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A miniature circuit breaker, comprising a housing and stationary contacts disposed within the housing, characterized in that: It also includes a three-bar linkage and a protection actuator; The three-bar linkage includes: Handle: Rotary setting on the housing; Moving contact: hinged to the handle; Linkage member: Rotatably mounted inside the housing and used to drive the moving contact to rotate and open the circuit breaker; Linkage spring: The two force-applying ends are respectively connected to the link and the moving contact. It is used to drive the link to rotate so as to push the moving contact to rotate and open the circuit. It is also used to drive the moving contact to rotate. The protective actuator is movable and used to restrict the rotation of the connecting rod. The protective actuator can release the rotation restriction on the connecting rod when the circuit is overloaded or short-circuited. A limit block is provided inside the housing. The limit block is located on the rotation path of the connecting rod and is used to restrict the rotation of the connecting rod. When the limit block abuts against the connecting rod, the connecting rod tension spring is located on the side away from the stationary contact at the hinge point between the moving contact and the handle. When the circuit is closed, the connecting rod spring is located on the side of the hinge point between the moving contact and the handle that is closer to the stationary contact; when the circuit is opened, the connecting rod spring is located on the side of the hinge point between the moving contact and the handle that is farther away from the stationary contact. When the tripping begins: F1 is the tension spring force of the connecting rod, and F2 is the thrust of the connecting rod on the moving contact. L1 is the lever arm of F1 on the connecting rod, and L2 is the lever arm of F2 on the connecting rod; L3 is the lever arm of F1 on the moving contact, and L4 is the lever arm of F2 on the moving contact.

2. A miniature circuit breaker according to claim 1, characterized in that: The handle is provided with a reset block, and the connecting rod is located on the rotation path of the reset block. When the circuit is opened, the reset block is used to push the connecting rod to rotate and reset until the protection actuator can re-limit the rotation of the connecting rod.

3. A miniature circuit breaker according to claim 1, characterized in that: The moving contact is provided with a flipping concave arc surface for contacting the connecting rod.

4. A miniature circuit breaker according to claim 1, characterized in that: The protection actuator includes a latch rotatably disposed within the housing, a protection actuator component for driving the latch to rotate, and a reset elastic element for driving the latch to reset. The latch has a locking groove for inserting the end of the connecting rod. When the circuit is overloaded or short-circuited, the protection actuator component drives the latch to rotate until the end of the connecting rod moves out of the locking groove.

5. A miniature circuit breaker according to claim 4, characterized in that: The protection actuator includes a movable armature rotatably disposed within the housing. The latch is provided with a short-circuit trigger. When the circuit is short-circuited, the movable armature can rotate to contact the short-circuit trigger and cause the latch to rotate until the end of the connecting rod moves out of the locking groove.

6. A miniature circuit breaker according to claim 5, characterized in that: The reset elastic element is a torsion spring. The two force-applying ends of the reset elastic element apply force to the latch and the moving armature respectively and are used to reset the latch and the moving armature.

7. A miniature circuit breaker according to claim 4, characterized in that: The latch is provided with multiple adjusting blocks, each of which is used to abut against the force-applying end of the reset elastic element.

8. A miniature circuit breaker according to claim 4, characterized in that: The latch is provided with an overload trigger, and the protection actuator includes a bimetallic strip for overload protection. When the circuit is overloaded, the bimetallic strip can deform to abut against the overload trigger and cause the latch to rotate until the end of the connecting rod moves out of the locking groove.

9. A miniature circuit breaker according to claim 1, characterized in that: It also includes an input terminal, and the protection actuator includes a protection actuation component, which includes a bimetallic strip for overload protection. The input terminal is electrically connected to the stationary contact via the bimetallic strip.

10. A miniature circuit breaker according to claim 4, characterized in that: The latch is provided with a linkage plug on one side along its own rotation direction, and a linkage seat is provided on the other side along its own rotation direction. The linkage seat has a linkage slot. The linkage plug and / or linkage seat extends through the housing. When multiple miniature circuit breakers are combined, the linkage plug of one miniature circuit breaker is used to insert into the linkage slot of the adjacent miniature circuit breaker.

Images