A circuit breaker

Abstract

The present invention provides a circuit breaker, comprising: a housing; a tripping lever; a contact assembly including a moving contact and a stationary contact, the stationary contact being fixed within the housing; a rotating mechanism rotatably connected to the housing, a part of the moving contact being located within the rotating mechanism and rotatably connected to the moving contact; a stroke amplification mechanism disposed between the moving contact and the rotating mechanism, the stroke amplification mechanism being connected to the moving contact and the rotating mechanism respectively, and the stroke amplification mechanism extending in a direction close to the tripping lever. In a short-circuit state, the repulsive force between the moving contact and the stationary contact causes the moving contact and the stroke amplification mechanism to rotate relative to the rotating mechanism, so that the stroke amplification mechanism pushes the tripping lever to rotate. The above circuit breaker is equivalent to adding a stroke amplification mechanism between the moving contact and the rotating mechanism in the prior art. Compared with the existing electromagnetic backup protection, the available space within the circuit breaker is increased, which is beneficial to the heat dissipation of the internal parts of the circuit breaker and extends the service life of the circuit breaker.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit breakers, and particularly relates to a circuit breaker. Background Art

[0002] The short-circuit protection of existing electronic circuit breakers is realized by relying on electronic components. Due to the slow response and processing speed of electronic components, the tripping time of electronic components is relatively long. In the case of large-current short circuits, a backup protection structure generally needs to be added to reduce the operating time of the circuit breaker under short-circuit current, thereby improving the current-limiting ability of the circuit breaker.

[0003] Currently, the commonly used backup protection structure for electronic circuit breakers is electromagnetic. For example, Chinese patent document CN10177090B discloses a backup protection tripping device for an electronic molded case circuit breaker, including: an armature, a bracket, a yoke, a pin shaft, a reaction spring, etc.

[0004] Existing electronic circuit breakers usually include components such as an operating mechanism, a moving contact, a static contact, a rotating mechanism, a tripping lever, etc. The static contact and the moving contact are arranged opposite to each other at intervals. The moving contact is inserted into the rotating mechanism cover, and the rotating mechanism is rotationally connected to the moving contact. The tripping lever is connected to the operating mechanism. And this backup protection tripping device is arranged outside the moving contact and the rotating structure. Through this backup protection tripping structure, the tripping lever rotates, and then the operating mechanism of the electronic circuit breaker trips, realizing the quick breaking of the circuit breaker. Since this backup protection tripping device is arranged outside the moving contact and the rotating mechanism, the internal structure of the electronic circuit breaker is quite crowded. Moreover, with the gradual increase in the demand for electronic circuit breakers with residual current protection functions, it is required to add a leakage module and conductor bending in the internal space of the existing electronic plastic case, which further makes the internal space of the electronic circuit breaker crowded, is not conducive to the heat dissipation of the internal parts of the electronic circuit breaker, makes the internal parts more likely to be damaged, and reduces the service life of the circuit breaker. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect of the crowded internal space of the electronic circuit breaker in the prior art, so as to provide a circuit breaker.

[0006] To solve the above technical problem, the present invention provides a circuit breaker, including:

[0007] A housing;

[0008] A tripping lever;

[0009] A contact assembly, including a moving contact and a static contact, the static contact is fixed in the housing, the moving contact and the static contact are arranged opposite to each other at intervals, and has a closing position where the moving contact contacts the static contact and a tripping position where the moving contact separates from the static contact;

[0010] A rotating mechanism, rotatably connected to the housing, with part of the moving contact located inside the rotating mechanism and rotatably connected to the moving contact;

[0011] A stroke amplification mechanism, arranged between the moving contact and the rotating mechanism, the stroke amplification mechanism is respectively connected to the moving contact and the rotating mechanism, and the stroke amplification mechanism extends towards the direction close to the tripping rod. In the normal opening and closing states, an external force causes the rotating mechanism, the moving contact and the stroke amplification mechanism to rotate synchronously, so that the stroke amplification mechanism does not contact the tripping rod;

[0012] In the short - circuit state, the repulsive force between the moving contact and the static contact causes the moving contact and the stroke amplification mechanism to rotate relative to the rotating mechanism, so that the stroke amplification mechanism pushes the tripping rod to rotate.

[0013] Optionally, the stroke amplification mechanism includes a first swing rod and a second swing rod connected to the first swing rod. The first swing rod is connected to the moving contact, one end of the second swing rod is connected to the rotating mechanism, and the other end extends towards the direction close to the tripping rod. In the short - circuit state, the stroke amplification mechanism rotates with the connection point between the first swing rod and the moving contact as the first fulcrum and the connection point between the second swing rod and the rotating mechanism as the second fulcrum, so that the second swing rod pushes the tripping rod to rotate.

[0014] Optionally, the connection point between the first swing rod and the second swing rod is close to the connection point between the second swing rod and the rotating mechanism.

[0015] Optionally, the second swing rod is a bent rod, and the opening of the bent rod is arranged towards the direction of the first swing rod.

[0016] Optionally, the bent rod is an arc - shaped rod.

[0017] Optionally, the first swing rod and the second swing rod are fixedly connected, the first swing rod is fixedly connected to the moving contact, and one end of the second swing rod is fixedly connected to the rotating mechanism.

[0018] Optionally, a rotating shaft is arranged at one end of the moving contact close to the stroke amplification mechanism, and the moving contact is rotatably connected to the rotating mechanism through the rotating shaft.

[0019] Optionally, a fixed shaft is arranged at one end of the moving contact close to the stroke amplification mechanism, an elastic member is arranged on the rotating shaft, one end of the elastic member abuts against the rotating mechanism, and the other end abuts against the fixed shaft. In the short - circuit state, the elastic member is used to drive the moving contact and the stroke amplification mechanism to reset.

[0020] Optionally, the moving contact and the rotating mechanism are suspended above the bottom plate of the housing.

[0021] Optionally, it further includes an operating mechanism disposed on the housing. The operating mechanism is connected to the tripping rod and is located above the rotating mechanism.

[0022] Optionally, it further includes an arc extinguishing cover. The contact point between the static contact and the moving contact is located inside the arc extinguishing cover, and the arc extinguishing cover is used to extinguish the arc between the moving contact and the static contact.

[0023] The technical solution of the present invention has the following advantages:

[0024] 1. The circuit breaker provided by the present invention includes a housing, a tripping rod, a contact assembly, a rotating mechanism, and a stroke amplification mechanism. The contacts are fixed inside the housing, and the moving contact and the static contact are arranged opposite to each other at intervals. During the opening and closing of the circuit breaker, the static contact and the moving contact can be normally separated and contacted. The rotating mechanism is rotatably connected to the housing. The rotating mechanism covers the moving contact and is rotatably connected to the moving contact. That is, the moving contact can rotate relative to the rotating mechanism, and the moving contact and the rotating mechanism can rotate synchronously relative to the housing. The stroke amplification mechanism is arranged between the moving contact and the rotating mechanism and is respectively connected to the moving contact and the rotating mechanism. At the same time, the stroke amplification mechanism extends in the direction close to the tripping rod. When the circuit breaker is normally opened and closed, the stroke amplification mechanism, the moving contact, and the rotating mechanism rotate synchronously, and the stroke amplification mechanism does not contact the tripping rod during the rotation process. In this way, when the circuit breaker is normally opened and closed, the stroke amplification mechanism will not contact other parts inside the circuit breaker, and thus will not affect the normal opening and closing of the circuit breaker. In the case of a large current short circuit, the repulsive force between the static contact and the moving contact drives the moving contact and the stroke amplification mechanism to rotate relative to the rotating mechanism. Since the moving contact can rotate relative to the rotating mechanism by a certain angle, the angle of rotation can be amplified by the stroke amplification mechanism. As a result, the stroke amplification mechanism can push the tripping rod to rotate during the rotation process, and after the tripping rod rotates, it can drive the operating mechanism to trip the circuit breaker.

[0025] This is equivalent to adding a stroke amplification mechanism between the moving contact and the rotating mechanism in the prior art, that is, making use of the original space between the moving contact and the rotating mechanism. Compared with the existing electromagnetic backup protection, the available space inside the circuit breaker is increased, which is beneficial to the heat dissipation of the internal parts of the circuit breaker and prolongs the service life of the circuit breaker.

[0026] 2. For the circuit breaker provided by the present invention, the stroke amplification mechanism includes a first swing rod and a second swing rod connected to the first swing rod. The first swing rod is connected to the moving contact. One end of the second swing rod is connected to the rotating mechanism, and the other end of the second swing rod rotates with the connection point between the first swing rod and the moving contact as the first fulcrum and the connection point between the second swing rod and the rotating mechanism as the second fulcrum in the short - circuit state. During the rotation process, the second swing rod can push the tripping rod to rotate. It can be seen that the backup protection of this circuit breaker is the first swing rod and the second swing rod. First of all, the volume of the first swing rod and the second swing rod is smaller than that of the electromagnetic backup protection in the prior art, reducing the occupied space of the backup protection in the circuit breaker. Secondly, the first swing rod and the second swing rod utilize the space between the existing rotating mechanism and the moving contact. Without changing the total volume of the rotating mechanism and the moving contact, part of the mechanisms of the first swing rod and the second swing rod are placed between the rotating mechanism and the moving contact, further increasing the available space inside the circuit breaker and facilitating the addition of other functional modules inside the circuit breaker in the future.

[0027] Thirdly, in the electromagnetic backup protection structure in the prior art, the suction force generated by magnetizing the yoke is used to counteract the elastic force of the reaction spring, and finally a striking force is formed to strike the tripping rod to make the tripping rod rotate. However, both the suction force generated by magnetizing the yoke and the elastic force of the spring are unstable. In order to ensure that the electromagnetic backup protection works under various currents, it is necessary to calibrate the position, angle, etc. of the spring multiple times. During the calibration process, the rated current needs to be amplified by more than ten times. In the case of large - current breaking at the instantaneous multiple of the moving contact and the static contact, serious electrical wear is likely to occur, thereby reducing the service life of the circuit breaker. The stroke amplification mechanism does not require the use of a spring. The rotation of the first swing rod and the second swing rod relies on the repulsive force between the static contact and the moving contact, and the repulsive force between the static contact and the moving contact can be controlled by the contact pressure between the moving contact and the static contact. The contact pressure is tested and approved for each existing circuit breaker. Moreover, the test and approval of the contact pressure are carried out by mechanically opening the moving contact and the static contact, which will not cause electrical wear to the moving contact and the static contact. That is, the circuit breaker with electromagnetic backup protection needs to carry out contact pressure test and approval and large - current calibration, while the circuit breaker of this application only needs to carry out contact pressure test and approval. Therefore, the circuit breaker of this application will not cause electrical wear to the moving contact and the static contact, and can extend the service life of the circuit breaker.

[0028] Finally, the electromagnetic backup protection structure in the prior art requires a reaction spring to rotate the trip lever. Due to the low elasticity accuracy of the reaction spring, the time interval from when the electromagnetic backup protection structure starts to operate to when it drives the trip lever to rotate is inconsistent, resulting in different tripping times for the operating mechanism each time. To ensure that the backup protection structure does not operate during the definite-time protection interval and short-time withstand test, a time interval must be reserved as a fault tolerance interval for various cumulative errors after the static contact and the moving contact are repelled and before the backup protection structure starts to operate. Moreover, the backup protection structure starts to operate after the moving contact and the static contact are repelled, which prolongs the tripping time and prevents the circuit breaker from interrupting the current quickly. In the present application, the stroke amplification mechanism is connected to the moving contact. When the moving contact starts to rotate, the stroke amplification mechanism also starts to rotate, and there is no time difference between them, shortening the time between the repulsion of the moving contact and the static contact and the rotation of the trip lever, thereby reducing the tripping time and enabling the circuit breaker to interrupt the current quickly. At the same time, the rotation angle of the moving contact relative to the rotation mechanism is determined by the repulsive force between the moving contact and the static contact, and the repulsive force between the moving contact and the static contact is determined by the peak short-circuit current passing through them. When the peak short-circuit current is constant, the consistency of the time interval from when the stroke amplification mechanism starts to operate to when it drives the trip lever to rotate is higher than that of the electromagnetic backup protection structure in the prior art.

[0029] 3. For the circuit breaker provided by the present invention, the connection point of the first swing rod and the second swing rod is close to the connection point of the second swing rod and the rotation mechanism, so that the rotation angle between the moving contact and the rotation mechanism can be amplified by a larger multiple to ensure that the second swing rod can push the trip lever to rotate during the repulsion process of the moving contact and the static contact.

[0030] 4. For the circuit breaker provided by the present invention, the second swing rod is a bent rod, and the opening of the bent rod is arranged towards the direction of the first swing rod. On the one hand, during normal opening and closing, the bent rod can ensure that the second swing rod does not touch the trip lever; on the other hand, during the short-circuit state, the bent rod can increase the contact area between the second swing rod and the trip lever, further ensuring that the second swing rod can push the trip lever to rotate during the repulsion process of the moving contact and the static contact.

[0031] 5. For the circuit breaker provided by the present invention, a rotating shaft is arranged at one end of the moving contact close to the stroke amplification mechanism, and the moving contact is rotatably connected to the rotation mechanism through the rotating shaft. When a force is applied to the rotation mechanism, the moving contact and the rotation mechanism can move synchronously. When a force is applied to the moving contact, the moving contact can rotate relative to the rotation mechanism through the rotating shaft. In this way, it can be ensured that during the normal opening and closing process of the circuit breaker, the stroke amplification mechanism does not affect its normal opening and closing, and when a short circuit occurs inside the circuit breaker, the stroke amplification mechanism can drive the trip lever to rotate, causing the operating mechanism to trip.

[0032] 6. The circuit breaker provided by the present invention has a fixed shaft disposed at one end of the moving contact close to the stroke amplification mechanism. A resilient member is disposed on the rotating shaft. One end of the resilient member abuts against the rotating mechanism, and the other end of the resilient member abuts against the fixed shaft. In a short-circuit state, the resilient member is used to drive the moving contact and the stroke amplification mechanism to reset. That is, when the moving contact and the stroke amplification mechanism rotate relative to the rotating mechanism, the resilient member will undergo elastic deformation to generate an elastic force. When the stroke amplification mechanism pushes the trip lever to rotate, causing the operating mechanism to trip, the moving contact and the stroke amplification mechanism can return to their original positions under the drive of the elastic force of the resilient member, facilitating subsequent normal opening and closing of the circuit breaker.

[0033] 7. The moving contact and the rotating mechanism of the circuit breaker provided by the present invention are suspended above the bottom plate of the housing. On the one hand, it can ensure that the moving contact and the rotating mechanism can rotate normally; on the other hand, it can increase the rotating space of the moving contact and the rotating mechanism. Furthermore, when the moving contact and the stroke amplification mechanism rotate relative to the rotating mechanism, the rotating space of the stroke amplification mechanism is increased, ensuring that the stroke amplification mechanism can abut against the trip lever and push the trip lever to rotate.

[0034] 8. The operating mechanism of the circuit breaker provided by the present invention is disposed on the housing. The operating mechanism is connected to the trip lever, and the operating mechanism is located above the rotating mechanism so that the operating mechanism can trip normally when the trip lever rotates. At the same time, in the normal opening and closing states of the circuit breaker, the pressure of the operating mechanism can be directly applied to the rotating mechanism, enabling the rotating mechanism, the moving contact, and the stroke amplification mechanism to rotate synchronously.

[0035] 9. The contact point between the static contact and the moving contact of the circuit breaker provided by the present invention is located within the arc extinguishing cover. The arc extinguishing cover is used to extinguish the arc between the moving contact and the static contact, preventing the arc from damaging the moving contact and the static contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 It is a top view of the circuit breaker in the closed state provided in the specific embodiment of the present invention;

[0038] Figure 2 is Figure 1 a cross-sectional view taken along line A-A in

[0039] Figure 3 a partial schematic diagram of the circuit breaker in the closed state provided in the specific embodiment of the present invention;

[0040] Figure 4 It is a top view of the repulsion state between the moving contact and the static contact of the circuit breaker when a short circuit occurs in the specific embodiment of the present invention;

[0041] Figure 5 is Figure 4 a cross-sectional view taken along line B-B in

[0042] Description of the reference numerals:

[0043] 1. Housing; 2. Tripping lever; 3. Static contact; 4. Moving contact; 5. Rotating mechanism; 6. Stroke amplification mechanism; 61. First swing rod; 62. Second swing rod; 7. Fixed shaft; 8. Rotating shaft; 9. Elastic member; 10. Conducting wire; 11. Arc extinguishing cover; 12. Operating mechanism. Specific embodiment

[0044] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0046] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0047] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] As Figures 1 to 5 shown, a specific embodiment of the circuit breaker includes:

[0049] Housing 1.

[0050] Tripping lever 2.

[0051] Contact assembly, including a moving contact 4 and a static contact 3. The static contact 3 is fixed inside the housing 1. The moving contact 4 is arranged opposite to the static contact 3 at an interval and has a closing position where the moving contact 4 contacts the static contact 3, and a tripping position where the moving contact 4 separates from the static contact 3. That is, when the circuit breaker is in the closing position, the moving contact 4 contacts the static contact 3 to energize between the moving contact 4 and the static contact 5. When the circuit breaker is in the tripping position, the moving contact 4 separates from the static contact 5 to de-energize between the moving contact 4 and the static contact 5.

[0052] Rotating mechanism 5, rotatably connected to the housing 1. Part of the moving contact 4 is located inside the rotating mechanism 5 and is rotatably connected to the moving contact 4.

[0053] Stroke amplification mechanism 6, arranged between the moving contact 4 and the rotating mechanism 5. The stroke amplification mechanism 6 is respectively connected to the moving contact 4 and the rotating mechanism 5, and the stroke amplification mechanism 6 extends in the direction close to the tripping lever 2. In the normal tripping and closing states, an external force causes the rotating mechanism 5, the moving contact 4 and the stroke amplification mechanism 6 to rotate synchronously, so that the stroke amplification mechanism 6 does not contact the tripping lever 2.

[0054] In a short - circuit state, the repulsive force between the moving contact 4 and the static contact 3 causes the moving contact 4 and the stroke amplification mechanism 6 to rotate relative to the rotating mechanism 5, so that the stroke amplification mechanism 6 pushes the tripping lever 2 to rotate.

[0055] The above circuit breaker includes a housing 1, a tripping lever 2, a contact assembly, a rotating mechanism 5 and a stroke amplification mechanism 6. The contacts are fixed inside the housing 1. The moving contact 4 and the static contact 3 are arranged opposite to each other at intervals. During the opening and closing processes of the circuit breaker, the static contact 3 and the moving contact 4 can be normally separated and contacted. The rotating mechanism 5 is rotatably connected to the housing 1. The rotating mechanism 5 covers the moving contact 4 and is rotatably connected to the moving contact 4, that is, the moving contact 4 can rotate relative to the rotating mechanism 5, and the moving contact 4 and the rotating mechanism 5 can rotate synchronously relative to the housing 1. The stroke amplification mechanism 6 is arranged between the moving contact 4 and the rotating mechanism 5. The stroke amplification mechanism 6 is respectively connected to the moving contact 4 and the rotating mechanism 5. At the same time, the stroke amplification mechanism 6 extends in the direction close to the tripping lever 2. When the circuit breaker is normally opening and closing, the moving contact 4, the rotating mechanism 5 and the stroke amplification mechanism 6 rotate synchronously, and the stroke amplification mechanism 6 does not contact the tripping lever 2 during the rotation process. In this way, when the circuit breaker is normally opening and closing, the stroke amplification mechanism 6 does not contact other parts inside the circuit breaker, and thus does not affect the normal opening and closing of the circuit breaker. In the case of a large current short circuit, the repulsive force between the static contact 3 and the moving contact 4 drives the moving contact 4 and the stroke amplification mechanism 6 to rotate relative to the rotating mechanism 5. Since the moving contact 4 can rotate relative to the rotating mechanism 5 by a certain angle, the angle of its rotation can be amplified by the stroke amplification mechanism 6, so that the stroke amplification mechanism 6 can push the tripping lever 2 to rotate during the rotation process. After the tripping lever 2 rotates, it can drive the operating mechanism 12 to trip the circuit breaker.

[0056] This is equivalent to adding a stroke amplification mechanism 6 between the moving contact 4 and the rotating mechanism 5 in the prior art, that is, the original space between the moving contact 4 and the rotating mechanism 5 is utilized. Compared with the existing electromagnetic backup protection, the available space inside the circuit breaker is increased, which is beneficial to the heat dissipation of the internal parts of the circuit breaker and prolongs the service life of the circuit breaker.

[0057] It can be understood that the meaning that part of the moving contact 4 is located inside the rotating mechanism 5 is that part of the structure of a moving contact 4 is located inside a rotating mechanism 5. When there are multiple moving contacts 4 inside the circuit breaker, there are also multiple rotating mechanisms 5, and the moving contacts 4 and the rotating mechanisms 5 are arranged in one-to-one correspondence.

[0058] Such as Figure 2 、 Figure 3 and Figure 5As shown, the stroke amplification mechanism 6 includes a first swing rod 61 and a second swing rod 62 connected to the first swing rod 61. The first swing rod 61 is connected to the moving contact 4. One end of the second swing rod 62 is connected to the rotating mechanism 5, and the other end extends towards the tripping rod 2. In the short - circuit state, the stroke amplification mechanism 6 rotates with the connection point of the first swing rod 61 and the moving contact 4 as the first fulcrum and the connection point of the second swing rod 62 and the rotating mechanism 5 as the second fulcrum, so that the second swing rod 62 pushes the tripping rod 2 to rotate.

[0059] It can be seen from this that the backup protection of this circuit breaker is the first swing rod 61 and the second swing rod 62. First of all, the volumes of the first swing rod 61 and the second swing rod 62 are smaller than those of the electromagnetic - type backup protection in the prior art, reducing the occupied space of the backup protection in the circuit breaker. Secondly, the first swing rod 61 and the second swing rod 62 utilize the space between the existing rotating mechanism 5 and the moving contact 4. Without changing the total volume of the rotating mechanism 5 and the moving contact 4, part of the mechanisms of the first swing rod 61 and the second swing rod 62 are placed between the rotating mechanism 5 and the moving contact 4, which further increases the available space inside the circuit breaker, facilitating the addition of other functional modules inside the circuit breaker subsequently.

[0060] Thirdly, in the electromagnetic - type backup protection structure in the prior art, the suction force generated by magnetizing the yoke is used to counteract the elastic force of the reaction spring, and finally a striking force is formed to strike the tripping rod to make the tripping rod rotate. However, both the suction force generated by magnetizing the yoke and the elastic force of the spring are unstable. In order to ensure that the electromagnetic - type backup protection works under various currents, it is necessary to calibrate the position, angle, etc. of the spring many times. During the calibration process, the rated current needs to be magnified by more than ten times. In the case of large - current breaking at the instantaneous multiple of the moving contact and the static contact, serious electrical wear is likely to occur, thereby reducing the service life of the circuit breaker. The stroke amplification mechanism 6 does not require the use of a spring. The rotation of the first swing rod 61 and the second swing rod 62 relies on the repulsive force (the force generated in the short - circuit case) between the static contact 3 and the moving contact 4, and the repulsive force between the static contact 3 and the moving contact 4 can be controlled by the contact pressure between the moving contact 4 and the static contact 3. The contact pressure is tested and approved for each existing circuit breaker, and the test and approval of the contact pressure are carried out by mechanically opening the moving contact 4 and the static contact 3, which will not cause electrical wear to the moving contact 4 and the static contact 3. That is, the circuit breaker with electromagnetic - type backup protection needs to carry out contact pressure test and approval and large - current calibration, while the circuit breaker of this application only needs to carry out contact pressure test and approval. Therefore, the circuit breaker of this application will not cause electrical wear to the moving contact 4 and the static contact 3, and can extend the service life of the circuit breaker.

[0061] Finally, the electromagnetic backup protection structure in the prior art requires a reaction spring to rotate the trip lever. Due to the low spring force accuracy of the reaction spring, the time interval from the start of the electromagnetic backup protection structure to driving the rotation of the trip lever is inconsistent, resulting in different trip times for each operation mechanism. To ensure that the backup protection structure does not operate during the definite-time protection interval and short-time withstand test, a time interval must be reserved as a fault tolerance interval for various cumulative errors after the static contact and the moving contact are repelled and before the backup protection structure starts to operate. Moreover, the start of the backup protection structure lags behind the repulsion of the moving contact and the static contact, which prolongs the trip time and makes the circuit breaker unable to cut off the current quickly. In the present application, the stroke amplification mechanism 6 is connected to the moving contact 4. When the moving contact 4 starts to rotate, the stroke amplification mechanism 6 also starts to rotate, and there is no time difference between them, shortening the time between the repulsion of the moving contact 4 and the static contact 3 and the rotation of the trip lever 2, thereby reducing the trip time and enabling the circuit breaker to cut off the current quickly. At the same time, the rotation angle of the moving contact 4 relative to the rotation mechanism 5 is determined by the repulsive force between the moving contact 4 and the static contact 3, and the repulsive force between the moving contact 4 and the static contact 3 is determined by the peak short-circuit current passing through them. When the peak short-circuit current is constant, the consistency of the time interval from the start of the stroke amplification mechanism 6 to driving the rotation of the trip lever 2 is higher than that of the electromagnetic backup protection structure in the prior art.

[0062] As Figure 2 , Figure 3 and Figure 5 shown, the first swing rod 61 and the second swing rod 62 are fixedly connected. The first swing rod 61 is fixedly connected to the moving contact 4, and one end of the second swing rod 62 is fixedly connected to the rotation mechanism 5. This can make the positions of the first swing rod 61, the second swing rod 62, the moving contact 4 and the rotation mechanism 5 more firm, and further make the stroke amplification effect of the stroke amplification mechanism 6 more accurate.

[0063] As Figure 3 shown, the connection point of the first swing rod 61 and the second swing rod 62 is close to the connection point of the second swing rod 62 and the rotation mechanism 5. This can magnify the rotation angle between the moving contact 4 and the rotation mechanism 5 by a larger multiple to ensure that the second swing rod 62 can push the trip lever 2 to rotate during the repulsion process of the moving contact 4 and the static contact 3.

[0064] As Figure 2 , Figure 3 and Figure 5As shown, the second swing rod 62 is a bent rod, and the opening of the bent rod is arranged towards the direction of the first swing rod 61. On the one hand, during normal opening and closing, the bent rod can ensure that the second swing rod 62 does not touch the trip rod 2; on the other hand, during a short - circuit state, the bent rod can increase the contact area between the second swing rod 62 and the trip rod 2, further ensuring that the second swing rod 62 can push the trip rod 2 to rotate during the process of the moving contact 4 repelling from the static contact 3.

[0065] There is no limit to the shape of the bent rod. In the normal opening and closing states, the bent rod does not touch the trip rod 2, and in the short - circuit state, the bent rod can touch the trip rod 2 and push the trip rod 2 to rotate. For example, in order to ensure that the bent rod can push the trip rod 2 to rotate and make the trip rod 2 drive the operating mechanism 12 to trip reliably, the bent rod can be an arc - shaped rod, composed of multiple spliced broken - line rods, or composed of multiple spliced broken - line and arc segments. In order to further ensure that the bent rod does not touch the trip rod 2 in the normal opening and closing states and can touch the trip rod 2 and push the trip rod 2 to rotate in the short - circuit state, the bent rod is an arc - shaped rod, and the arc - shaped rod can be an arc - shaped rod spliced by multiple arcs, and the radius of each arc can be equal or unequal.

[0066] As Figure 2 , Figure 3 and Figure 5 shown, a rotating shaft 8 is arranged at one end of the moving contact 4 close to the stroke amplification mechanism 6, and the moving contact 4 is rotationally connected to the rotating mechanism 5 through the rotating shaft 8. When a force is applied to the rotating mechanism 5, the moving contact 4 and the rotating mechanism 5 can move synchronously. When a force is applied to the moving contact 4, the moving contact 4 can rotate relative to the rotating mechanism 5 through the rotating shaft 8. This can ensure that during the normal opening and closing processes of the circuit breaker, the stroke amplification mechanism 6 does not affect its normal opening and closing, and when a short - circuit occurs inside the circuit breaker, the stroke amplification mechanism 6 can drive the trip rod 2 to rotate and make the operating mechanism 12 trip.

[0067] As Figure 2 , Figure 3 and Figure 5 shown, a fixed shaft 7 is arranged at one end of the moving contact 4 close to the stroke amplification mechanism 6, an elastic member 9 is arranged on the rotating shaft 8, one end of the elastic member 9 abuts against the rotating mechanism 5, and the other end abuts against the fixed shaft 7. In the short - circuit state, the elastic member 9 is used to drive the moving contact 4 and the stroke amplification mechanism 6 to reset. That is, when the moving contact 4 and the stroke amplification mechanism 6 rotate relative to the rotating mechanism 5, the elastic member 9 will undergo elastic deformation to generate an elastic force. When the stroke amplification mechanism 6 pushes the trip rod 2 to rotate and makes the operating mechanism 12 trip, the moving contact 4 and the stroke amplification mechanism 6 can return to their original positions under the driving of the elastic force of the elastic member 9, facilitating subsequent normal opening and closing.

[0068] The elastic member 9 can be a torsion spring or other elastic structures with the above functions.

[0069] As Figure 2 and Figure 5 shown, the moving contact 4 and the rotating mechanism 5 are suspended above the bottom plate of the housing 1. On the one hand, it can ensure that the moving contact 4 and the rotating mechanism 5 can rotate normally; on the other hand, it can increase the rotating space of the moving contact 4 and the rotating mechanism 5. Furthermore, when the moving contact 4 and the stroke amplification mechanism 6 rotate relative to the rotating mechanism 5, the rotating space of the stroke amplification mechanism 6 is increased, ensuring that the stroke amplification mechanism 6 can abut against the tripping lever 2 and push the tripping lever 2 to rotate.

[0070] As Figure 2 , Figure 3 and Figure 5 shown, the circuit breaker further includes an operating mechanism 12 provided on the housing 1. The operating mechanism 12 is connected to the tripping lever 2, and the operating mechanism 12 is located above the rotating mechanism 5 so that the operating mechanism 12 can trip normally when the tripping lever 2 rotates. At the same time, in the normal opening and closing states of the circuit breaker, the pressure of the operating mechanism 12 can be directly applied to the rotating mechanism 5, so that the rotating mechanism 5, the moving contact 4 and the stroke amplification mechanism 6 can rotate synchronously.

[0071] As Figure 2 , Figure 3 and Figure 5 shown, the circuit breaker further includes an arc extinguishing cover 11. The contact point between the static contact 3 and the moving contact 4 is located within the arc extinguishing cover 11. The arc extinguishing cover 11 is used to extinguish the arc between the moving contact 4 and the static contact 3 to prevent the arc from damaging the moving contact 4 and the static contact 3.

[0072] As Figure 2 , Figure 3 and Figure 5 shown, the circuit breaker further includes a wire 10 and a wiring board. The wire 10 is respectively connected to the moving contact 4 and the wiring board, and the wiring board is connected to the bottom plate of the housing 1.

[0073] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A circuit breaker, characterized in that, it includes: a housing (1); a tripping lever (2); a contact assembly, including a moving contact (4) and a stationary contact (3), the stationary contact (3) is fixed within the housing (1), the moving contact (4) is disposed opposite the stationary contact (3) at an interval, and has a closing position where the moving contact (4) contacts the stationary contact (3), and a tripping position where the moving contact (4) separates from the stationary contact (3); a rotating mechanism (5), rotatably connected to the housing (1), a part of the moving contact (4) is located within the rotating mechanism (5), and the rotating mechanism (5) is rotationally connected to the moving contact (4); a stroke amplification mechanism (6), disposed between the moving contact (4) and the rotating mechanism (5), the stroke amplification mechanism (6) is respectively connected to the moving contact (4) and the rotating mechanism (5), and the stroke amplification mechanism (6) extends out of the rotating mechanism (5) and extends in a direction close to the tripping lever (2). In normal tripping and closing states, an external force causes the rotating mechanism (5), the moving contact (4) and the stroke amplification mechanism (6) to rotate synchronously, so that the stroke amplification mechanism (6) does not contact the tripping lever (2); In a short - circuit state, the repulsive force between the moving contact (4) and the stationary contact (3) causes the moving contact (4) and the stroke amplification mechanism (6) to rotate relative to the rotating mechanism (5), so that the stroke amplification mechanism (6) pushes the tripping lever (2) to rotate; The stroke amplification mechanism (6) includes a first swing rod (61) and a second swing rod (62) connected to the first swing rod (61). The first swing rod (61) and the second swing rod (62) are the backup protection of the circuit breaker. The first swing rod (61) is connected to the moving contact (4), one end of the second swing rod (62) is connected to the rotating mechanism (5), and the other end extends in a direction close to the tripping lever (2). In a short - circuit state, the stroke amplification mechanism (6) rotates with the connection point between the first swing rod (61) and the moving contact (4) as the first fulcrum and the connection point between the second swing rod (62) and the rotating mechanism (5) as the second fulcrum, so that the second swing rod (62) pushes the tripping lever (2) to rotate; The connection point between the first swing rod (61) and the second swing rod (62) is close to the connection point between the second swing rod (62) and the rotating mechanism (5). The second swing rod (62) is a bent rod, the opening of the bent rod is arranged in the direction of the first swing rod (61), and the bent rod is an arc - shaped rod.

2. The circuit breaker according to claim 1, characterized in that, the first swing rod (61) and the second swing rod (62) are fixedly connected, the first swing rod (61) is fixedly connected to the moving contact (4), and one end of the second swing rod (62) is fixedly connected to the rotating mechanism (5).

3. The circuit breaker according to claim 1 or 2, characterized in that, One end of the moving contact (4) close to the stroke amplification mechanism (6) is provided with a rotating shaft (8), and the moving contact (4) is rotatably connected to the rotating mechanism (5) through the rotating shaft (8).

4. The circuit breaker according to claim 3, wherein, One end of the moving contact (4) close to the stroke amplification mechanism (6) is provided with a fixed shaft (7), an elastic member (9) is arranged on the rotating shaft (8), one end of the elastic member (9) abuts against the rotating mechanism (5), and the other end abuts against the fixed shaft (7). In a short-circuit state, the elastic member (9) is used to drive the moving contact (4) and the stroke amplification mechanism (6) to reset.

5. The circuit breaker according to claim 3, wherein, The moving contact (4) and the rotating mechanism (5) are suspended above the bottom plate of the housing (1).

6. The circuit breaker according to claim 3, wherein, It further includes an arc extinguishing cover (11), the contact point between the static contact (3) and the moving contact (4) is located in the arc extinguishing cover (11), and the arc extinguishing cover (11) is used to extinguish the arc between the moving contact (4) and the static contact (3).

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