CN111463079A

CN111463079A - Circuit breaker

Info

Publication number: CN111463079A
Application number: CN201910047458.5A
Authority: CN
Inventors: 李祎博; 李波; 罗梦翔; 刘毅
Original assignee: Schneider Electric Industries SAS
Current assignee: Schneider Electric Industries SAS
Priority date: 2019-01-18
Filing date: 2019-01-18
Publication date: 2020-07-28
Anticipated expiration: 2039-01-18
Also published as: CN111463079B

Abstract

The invention provides a circuit breaker which comprises a breaking unit, a lever, a synchronizing shaft and an operating mechanism. The breaking unit comprises a moving contact, a fixed contact and a main shaft which are positioned on the inner side of the closed shell. The movable contact is mounted on a main shaft, and the main shaft is configured to rotate around a first rotating shaft. The lever is located on the outer side of the housing and configured to rotate around the second rotating shaft. A synchronizing shaft passes through the housing and extends parallel to the first and second shafts, the synchronizing shaft being mounted to the main shaft at an inner side of the housing and to the lever at an outer side of the housing. The operating mechanism is positioned on the outer side of the shell and is connected with and drives the lever to rotate, and the lever drives the main shaft to rotate through the synchronizing shaft. According to the invention, because the shell is closed, the breaking and closing of the moving contact and the static contact can not be interfered by the external environment; in addition, in a closed environment, the short circuit is beneficial to forming larger air pressure elongated electric arc and extinguishing the electric arc, so that the breaking performance of the circuit breaker is improved.

Description

Circuit breaker

Technical Field

The present invention relates to a circuit breaker.

Background

Circuit breakers are common electrical devices used to automatically break an electrical circuit when excessive abnormal current flows in the circuit (e.g., an overload or a short circuit) to protect the safety of equipment and personnel. The circuit breaker comprises a fixed contact and a movable contact which are respectively connected to a connecting terminal, and the fixed contact and the movable contact form a normally closed breakpoint. When the breaking is needed, the moving contact is rotated by the operating mechanism to be disconnected with the fixed contact, so that the circuit is disconnected. The arc extinguishing chamber is used for extinguishing electric arc generated between the moving contact and the fixed contact.

According to the number of breakpoints, the circuit breaker can be a double-breakpoint circuit breaker and a single-breakpoint circuit breaker. The double-breakpoint circuit breaker comprises two moving contacts which are symmetrically arranged and rotate simultaneously, and are used for being respectively closed or disconnected with respective fixed contacts, and two groups of arc extinguish chambers are needed. Different from the circuit breaker, the single-breakpoint circuit breaker only comprises a pair of moving contacts and fixed contacts, only needs one group of arc extinguish chambers, and can remarkably reduce the volume of the circuit breaker and reduce the cost. However, in the single-break circuit breaker in the prior art, a lower connecting rod of the operating mechanism is directly connected to a main shaft linked with the movable contact, and is limited by the volume of an internal space, the rotating angle of the main shaft is limited, and the opening distance is small; moreover, the moving contact and the fixed contact are usually exposed to the external environment, so that the breaking action is easily influenced by the external environment.

Accordingly, it is desirable to provide a circuit breaker with improved breaking capability.

Disclosure of Invention

The present invention is directed to solving at least one problem posed by the prior art. More precisely, it is an object of the present invention to provide a circuit breaker with improved breaking capacity.

The invention provides a circuit breaker, which comprises a breaking unit, wherein the breaking unit comprises a moving contact, a fixed contact, a main shaft and a closed shell, the moving contact, the fixed contact and the main shaft are all positioned on the inner side of the shell, the moving contact is installed on the main shaft, the main shaft is configured to rotate around a first rotating shaft between a first main shaft position and a second main shaft position which are separated by a first angle, the moving contact is in contact with the fixed contact at the first main shaft position, and the moving contact and the fixed contact are broken at the second main shaft position. The lever is located on the outer side of the shell and configured to rotate around a second rotating shaft, and the second rotating shaft is parallel to the first rotating shaft. A synchronizing shaft passes through the housing and extends parallel to the first rotation shaft, inside the housing the synchronizing shaft being mounted to the main shaft, outside the housing the synchronizing shaft being mounted to the lever. And the operating mechanism is positioned on the outer side of the shell, is connected to the lever and is configured to drive the lever to rotate by a second angle, so that the lever drives the spindle to rotate by the first angle through the synchronous shaft.

According to the invention, the moving contact and the static contact are positioned in the closed shell, and the breaking and closing of the moving contact and the static contact cannot be interfered by the external environment; in addition, under a closed environment, the short circuit is beneficial to forming larger air pressure, lengthening electric arcs and extinguishing the electric arcs when the short circuit occurs, so that the breaking performance of the circuit breaker is improved.

In the first aspect, the first rotation shaft and the second rotation shaft may be misaligned, and the first rotation shaft is closer to the synchronization shaft than the second rotation shaft such that the first angle is larger than the second angle. Under the condition, the main shaft can be actuated to rotate at a larger angle by utilizing the lever rotating at a small angle, the opening distance of the circuit breaker is increased, the electric arc is quickly extinguished, and the safety of the circuit breaker is improved.

Alternatively, the first end of the lever is rotatably connected to the lower link of the operating mechanism, the second end of the lever has a sliding groove, the second end and the first end are located on both sides of the second rotating shaft, the synchronizing shaft is received in the sliding groove, and when the lever rotates through the second angle, the synchronizing shaft slides along the sliding groove while driving the main shaft to rotate through the first angle. Further alternatively, the first end of the lever may be rotatably connected to the lower link of the operating mechanism via a rivet.

In a second aspect, the first and second axes of rotation may coincide such that the first angle is equal to the second angle. Optionally, the circuit breaker may further include a second synchronizing shaft disposed through the housing, at an inner side of the housing, the second synchronizing shaft being mounted to the main shaft, and at an outer side of the housing, the second synchronizing shaft passing through the first end of the lever and the lower link of the operating mechanism such that the first end of the lever and the lower link of the operating mechanism are rotatably connected. Under the condition, the circuit breaker can utilize two synchronous shafts to drive the main shaft to rotate, so that the moving contact motion stability is improved, the synchronous shaft load is reduced, and the reliability is improved.

Alternatively, the second end of the lever may have a circular hole in which the synchronizing shaft is received, the synchronizing shaft and the second synchronizing shaft being symmetrical about the first rotating shaft and the second rotating shaft.

Optionally, the circuit breaker may further include: a backup protection device located inside the housing; a trip bar located outside of the housing; the tripping device comprises a tripping synchronizing shaft, a backup protection device and a tripping device, wherein the tripping synchronizing shaft penetrates through the shell, the tripping synchronizing shaft is arranged on the inner side of the shell, the tripping synchronizing shaft is arranged on a tripping rod on the outer side of the shell, and when the current flowing through the circuit breaker exceeds a threshold value, the backup protection device enables the operating mechanism to trip through the tripping rod.

Optionally, the backup protection device may include: a stationary armature fixed to the first connection terminal; a moving armature fixed to a moving armature bracket fixed to the trip synchronizing shaft; a spring that applies a spring force to hold the static armature and the moving armature away from each other; when the current flowing through the first connecting terminal exceeds a threshold value, the movable armature overcomes the spring force to move towards the static armature under the action of electromagnetic force, and the movable armature bracket and the tripping synchronous shaft are driven to rotate.

Alternatively, the breaking unit may comprise only a single pair of moving and stationary contacts. In this case, the present invention provides a single break point circuit breaker having advantages of compact volume and high reliability.

Optionally, the circuit breaker may further include a second breaking unit including a second movable contact, a second fixed contact, a second main shaft, and a second closed housing, where the second movable contact, the second fixed contact, and the second main shaft are all located inside the second housing. The lever is located outside the second housing, and the synchronizing shaft passes through the second housing and is mounted to the second main shaft inside the second housing. The operating mechanism is connected with and drives a lever to rotate by a second angle, and the lever drives the main shaft and the second main shaft to synchronously rotate by the first angle through the synchronous shaft. In this case, a plurality of breaking units in the circuit breaker may be each used to break the current of an individual phase, and a common synchronization shaft may drive the plurality of breaking units to be opened or closed in synchronization.

Alternatively, the circuit breaker may be three or four breaking units, which are opened or closed synchronously by means of a common synchronization shaft.

Drawings

The following drawings are included to better present some embodiments of the invention in conjunction with the description herein, to explain various features and advantages thereof as defined in the claims. Like reference symbols in the various drawings indicate like or corresponding parts.

Fig. 1 shows an exploded perspective view of a circuit breaker according to the present invention;

fig. 2 shows a partial side view of the circuit breaker according to the first embodiment in a closed state;

fig. 3 shows a partial side view of the circuit breaker according to the first embodiment in a breaking state;

figure 4 shows a partial side view of a circuit breaker according to a second embodiment;

figure 5 shows a partial side cross-sectional view of a circuit breaker according to a second embodiment.

Reference numerals

1 housing 10 synchronizing shaft

2 moving contact 11 second synchronous shaft

3 static contact 12 back-up protection device

4 static armature of main shaft 121

5 first connection terminal 122 moving armature

6 second terminal 123 spring

7 lever 124 moves armature support

71 chute 13 trip bar

8 operating mechanism 14 tripping synchronous shaft

81 handle 15 support

82 upper connecting rod 16 copper braided wire

83 lower connecting rod 17 arc extinguishing chamber

84 first lever A first axis of rotation

85 second rod B second rotating shaft

86 third rod U breaking unit

9 rivet

Detailed Description

A circuit breaker may be installed in an electric circuit via two connection terminals, and when an operation fault (e.g., a short circuit or an overcurrent) is detected, a current in the electric circuit may be interrupted. Fig. 1 shows an exploded perspective view of a circuit breaker according to an embodiment. The circuit breaker is provided with three parallel breaking units U, and each breaking unit U is used for one-phase circuit in a three-phase circuit. The three breaking units U may have the same structure and thus may be interchanged. The breaking unit U is mounted by a base and a cover of the circuit breaker. In further embodiments, the circuit breaker may comprise other numbers (e.g. one, two, four) of breaking units of the same or similar structure.

As shown in fig. 1, each breaking unit U has a closed casing 1, which may be bolted by two half-shells. "enclosed" means that the casing 1 substantially isolates the internal electrical components, such as the moving contacts and the static contacts, from the external environment, except for small openings for specific purposes, for example, holes or slots for the passage of at least one synchronizing shaft 10 may be provided in the side walls of the casing 1. The moving contact, the static contact, the arc extinguish chamber, the main shaft and other parts of the breaking unit U are all positioned in the closed shell 1. Therefore, the housing 1 can protect the internal electrical components from the adverse effect of the outside, and particularly, when the movable contact and the static contact are separated, the electric arc formed between the movable contact and the static contact is not affected by the external environment and can be reliably extinguished by the arc extinguishing chamber. In addition, the closed shell 1 limits the internal gas, which is beneficial to forming larger gas pressure during short circuit, lengthening the electric arc and being more beneficial to extinguishing the electric arc, thereby improving the breaking performance of the circuit breaker.

The circuit breaker is provided with an operating mechanism 8, and the operating mechanism is used for driving a main shaft positioned in the shell 1 to rotate, so that the moving contact is driven to rotate, and breaking is realized. The operating mechanism 8 can be operated to realize manual breaking, and a tripping device can also be used for realizing automatic breaking. In order to mount the operating mechanism 8 on the outside of the casing 1, the circuit breaker shown in fig. 1 is provided with two brackets 15 which are respectively mounted on both side walls of the breaking unit U which is interposed therebetween, and the operating mechanism 8 is mounted between the two brackets 15. The operating mechanism 8 can drive the main shaft of at least one breaking unit U in rotation via at least one synchronization shaft. As shown in fig. 1, the synchronizing shaft 10 may extend to the inside of the three cutting units U, respectively mounted to the main shaft inside each cutting unit U, so that the three cutting units U can be synchronously cut and closed. Near the bracket 15, the synchronizing shaft 10 is connected to the lower link of the operating mechanism 8 for receiving the driving force.

Fig. 2 and 3 illustrate a closed state and an open state of the circuit breaker according to the first embodiment of the present invention. The front part of the housing 1 is not shown to show the internal structure. The moving contact 2 is arranged on the main shaft 4 and can rotate around a first rotating shaft A along with the main shaft 4, and the moving contact 2 is electrically connected to the first connecting terminal 5 through a flexible deformed and moving copper braided wire 16; the stationary contact is fixedly mounted to the housing 1, which is electrically connected to the second connection terminal 6. Under normal conditions, the current in the circuit does not exceed the threshold value, and the circuit breaker remains in the closed condition shown in fig. 2, in which the movable contact 2 is in the first angular position extending downwards and in contact with the stationary contact 3, allowing the current to flow through the first connection terminal 5 and the second connection terminal 6. In abnormal situations, in which the current in the electric circuit exceeds a threshold value, for example an overload or short-circuit fault occurs in the electric circuit, the operating mechanism 8 is actuated manually or automatically and drives the spindle 4 in rotation, causing the movable contact 2 to rotate to the second angular position extending upwards, shown in fig. 3, and to be disconnected from the stationary contact 3. The arc extinguish chamber 17 is arranged near the moving contact 2 and the static contact 3, so that electric arcs can be extinguished quickly, and safety accidents are avoided.

As shown in fig. 2 and 3, the operating mechanism 8 includes a handle 81, an upper link 82, and a lower link 82. The handle 81 is connected to an upper link 82 via an energy storage spring, a lower end of the upper link 82 is rotatably connected to an upper end of a lower link 82, and a lower end of the lower link 82 is rotatably connected to a right end of the lever 7. When the handle 81 rotates from the closed position shown in fig. 2 to the breaking position shown in fig. 3, the energy storage spring releases potential energy, so that the upper connecting rod 82 rotates clockwise by a certain angle, the lower connecting rod 82 is driven to rotate counterclockwise by a certain angle, and then the right end of the lever 7 is pulled to move upwards by a certain distance.

The lever 7 is configured to rotate about the second rotation axis B, and the right end of the lever 7 is rotatably connected to the lower link 82, and in this first embodiment, the lever 7 and the lower link 82 are rotatably connected by a rivet 9. In other embodiments, other rotational connections such as pins may be used. The left end of the lever 7 is provided with a slide groove 71. The synchronizing shaft 10 is received in the slide groove 71 and is movable along the slide groove 71 in accordance with the swing of the lever 7. The synchronizing shaft 10 extends through the housing 1 and is mounted to the main shaft 4 inside the housing 1. As shown in fig. 3, the synchronizing shaft 10 extends parallel to and spaced apart from the first rotation axis a of the main shaft 4 and the second rotation axis B of the lever 7. Thus, when the lever 7 rotates by a second angle around the second rotation axis B, the sliding groove 71 pushes the synchronizing shaft 10 to move, thereby driving the main shaft 4 to rotate by a first angle around the first rotation axis a.

In this first embodiment, the first axis of rotation a of the spindle 4 and the second axis of rotation B of the lever 7 do not coincide but are spaced apart by a distance. Also, the second rotation axis B is not located at the middle position of the lever 7, but is located closer to the rivet 9 than the slide groove 71. In this case, the moment arm of the rivet 9 is smaller than that of the synchronizing shaft 10 on the lever 7, and therefore the synchronizing shaft 10 moves downward a greater distance than the rivet 9 moves upward. Further, the second rotation axis B of the lever 7 is arranged farther from the synchronizing shaft 10 than the first rotation axis a of the main shaft 4. In this case, the rotation angle of the spindle 4 will be larger than that of the lever 7. Therefore, compared with the case that the first rotating shaft a and the second rotating shaft B are arranged in a superposed manner, the present embodiment utilizes a smaller ascending stroke of the rivet 9 to realize a larger rotating angle of the main shaft 4, so that a distance (referred to as an "opening distance") separating the moving contact 2 and the static contact 3 in a disjunction state is larger, and a better disjunction effect is realized. Moreover, this design is also very advantageous for reducing the bulk of the circuit breaker, since there is no need to design a more complex, bulky operating mechanism 8 in order to meet the greater lifting travel of the rivet 9.

Fig. 4 and 5 show a circuit breaker according to a second embodiment of the present invention. The cross-sectional view of fig. 5 has the front housing portion, brackets, etc. removed from fig. 4 to better illustrate the internal structure. The second embodiment is substantially the same as the first embodiment described above, the main difference being that the first axis of rotation a of the spindle 4 and the second axis of rotation B of the lever 7 are coincident, as shown in the side view of fig. 4. In this case, the rotation angle of the spindle 4 is equal to the rotation angle of the lever 7. In addition, unlike the first embodiment, the lower end of the lower link 83 is not connected to the lever 7 via the rivet 9, but is connected to the right end of the lever 7 via another synchronizing shaft 11 (referred to as a "second synchronizing shaft"), as shown in fig. 4. A second synchronizing shaft 11 likewise extends through the housing 1 and is parallel to the first and second axes of rotation a, B, the second synchronizing shaft 11 and the first synchronizing shaft 10 being arranged in particular symmetrically with respect to the first axis of rotation a. Inside the housing 1, a second synchronizing shaft 11 is mounted to another location on the main shaft 4. On the outside of the housing 1, a second synchronizing shaft 11 extends through the lever 7 and the lower link 83 as a rotational connection therebetween. In this case, the lever 7 can drive the main shaft 4 to rotate via the two symmetrically arranged synchronizing

shafts

10 and 11, so that the rotation process of the main shaft 4 together with the movable contact 2 is more stable. And the rotating torque is distributed on the two synchronous shafts, so that the stress on a single synchronous shaft can be reduced, and the reliability is improved. In addition, the distance of the synchronizing shaft 10 with respect to the lever 7 is constant during the rotation of the lever 7, and therefore the synchronizing shaft 10 is rotatably received in a circular hole on the lever 7, instead of the slide groove in the first embodiment.

As shown in fig. 4, the outer side of the housing 1 is mounted with a bracket 15, which can support a portion of the second rotation axis B, providing a fulcrum for the rotation of the lever 7. In addition, a guide groove may be provided on the bracket 15 to guide the

synchronous shafts

10 and 11 to smoothly rotate.

Another difference between the second embodiment and the first embodiment described above is that a backup protection device 12 is provided inside the housing 1. The backup protection device 12 is a built-in electromagnetic trip device for actuating the trip bar 13 to trigger the circuit breaker to open when an overcurrent is detected. Specifically, the backup protection device 12 includes a stationary armature 121 and a movable armature 122, the stationary armature 121 is fixed to the first connection terminal 5, the movable armature 122 is fixed to a movable armature bracket 124, and a spring 123 is provided between the stationary armature 121 and the movable armature 122 for biasing them away from each other. The moving armature bracket 124 is arranged to rotate about its rotational axis, and the moving armature bracket 124 and the trip synchronizing shaft 14 are coaxially coupled. As shown in fig. 5, the components of the backup protection device 12 are located inside the closed chamber of the housing 1 so as not to be subject to external interference (e.g., electromagnetic interference). When the current flowing through the first connection terminal 5 exceeds a threshold value, the movable armature 122 moves toward the stationary armature 121 against the spring force of the spring 123 under the action of the electromagnetic force, and rotates the movable armature holder 124 and the trip synchronizing shaft 14. The trip synchronizing shaft 14 passes through the housing 1 and is fixedly connected to and drives the trip lever 13 at the outside of the housing 1. It should be noted that the backup protection devices described herein are exemplary only, and those skilled in the art may employ other backup protection devices, either previously known or developed in the future.

The operating mechanism 8 can be locked at a closed position to keep the moving contact 2 and the static contact 3 closed; meanwhile, the moving contact 2 and the static contact 3 can be driven to trip under the actuation of the trip rod 13 and rotate to a breaking position, so that the moving contact 2 and the static contact 3 are broken. Referring to fig. 5, the latch mechanism of the operating mechanism 8 may include a first lever 84, a second lever 85, and a third lever 86. The right arc of the third lever 86 may abut the inner arc of the handle 81 and the left arc may abut the abutment surface of the second lever 85. The upper end of the second rod 85 abuts against the upper end of the first rod 84. Under the bias of the resilient element, the first lever 84 can exert a latch holding force on the third lever 86 via the second lever 85, holding the handle 81 in the closed position. When the trip lever 13 is rotated, the upper end thereof pushes the lower end of the first lever 84, so that the first lever 84 is rotated. In turn, the upper end of the first lever 84 releases the upper end of the second lever 85, thereby unloading the latch holding force exerted on the third lever 86. At this time, under the action of the energy storage spring, the handle 81 is rotated to the breaking position shown in fig. 5, and as described above, the lever 7 is rotated via the upper link 82 and the lower link 83, and the spindle 4 is then rotated, so that the movable contact 2 and the stationary contact 3 are separated. It should be noted that the latching mechanisms described herein are exemplary only, and that other latching mechanisms, previously known or later developed, may be employed by those skilled in the art.

Some embodiments for implementing the invention have been described in detail above, but it should be understood that they have been presented by way of example only, and not limitation to the scope, applicability, or configuration of the invention in any way. The scope of the invention is defined by the appended claims and equivalents thereof. Many modifications may be made to the foregoing embodiments by those skilled in the art, which modifications are within the scope of the invention.

Claims

1. A circuit breaker, comprising:

the breaking unit comprises a moving contact, a fixed contact, a main shaft and a closed shell, wherein the moving contact, the fixed contact and the main shaft are all positioned on the inner side of the shell, the moving contact is installed on the main shaft, the main shaft is configured to rotate around a first rotating shaft between a first main shaft position and a second main shaft position which are separated by a first angle, the moving contact is in contact with the fixed contact at the first main shaft position, and the moving contact is broken at the second main shaft position;

the lever is positioned on the outer side of the shell and is configured to rotate around a second rotating shaft, and the second rotating shaft is parallel to the first rotating shaft;

a synchronizing shaft passing through the housing and extending parallel to the first rotating shaft, the synchronizing shaft being mounted to the main shaft at an inner side of the housing, and the synchronizing shaft being mounted to the lever at an outer side of the housing; and

and the operating mechanism is positioned on the outer side of the shell, is connected to the lever and is configured to drive the lever to rotate by a second angle, so that the lever drives the spindle to rotate by the first angle through the synchronous shaft.

2. The circuit breaker of claim 1,

the first rotating shaft and the second rotating shaft are not coincident, and the first rotating shaft is closer to the synchronizing shaft than the second rotating shaft, so that the first angle is larger than the second angle.

3. The circuit breaker of claim 2,

the first end of the lever is rotatably connected to the lower connecting rod of the operating mechanism;

the second end of the lever is provided with a sliding groove, the second end and the first end are located on two sides of the second rotating shaft, the synchronizing shaft is received in the sliding groove, and when the lever rotates by a second angle, the synchronizing shaft slides along the sliding groove and drives the main shaft to rotate by a first angle.

4. The circuit breaker of claim 3,

the first end of the lever is rotatably connected to the lower link of the operating mechanism via a rivet.

5. The circuit breaker of claim 1, wherein the first axis of rotation and the second axis of rotation coincide such that the first angle is equal to the second angle.

6. The circuit breaker of claim 5, further comprising:

and a second synchronizing shaft disposed through the housing and extending parallel to the synchronizing shaft, the second synchronizing shaft being mounted to the main shaft at an inner side of the housing, the second synchronizing shaft passing through the first end of the lever and the lower link of the operating mechanism at an outer side of the housing such that the first end of the lever and the lower link of the operating mechanism are rotatably connected.

7. The circuit breaker of claim 6,

the second end of the lever has a circular hole in which the synchronizing shaft is received, the synchronizing shaft and the second synchronizing shaft being symmetrical about the first rotational axis.

8. The circuit breaker according to any one of claims 1-7, further comprising:

a backup protection device located inside the housing;

a trip bar located outside of the housing;

the tripping device comprises a tripping synchronizing shaft, a backup protection device and a tripping device, wherein the tripping synchronizing shaft penetrates through the shell, the tripping synchronizing shaft is arranged on the inner side of the shell, the tripping synchronizing shaft is arranged on a tripping rod on the outer side of the shell, and when the current flowing through the circuit breaker exceeds a threshold value, the backup protection device enables the operating mechanism to trip through the tripping rod.

9. The circuit breaker according to any of claims 1-7,

the breaking unit only comprises a single pair of moving contact and static contact.

10. The circuit breaker according to any one of claims 1-7, further comprising:

the second breaking unit comprises a second moving contact, a second fixed contact, a second main shaft and a closed second shell, and the second moving contact, the second fixed contact and the second main shaft are all positioned on the inner side of the second shell;

wherein the lever is located outside the second housing, and the synchronizing shaft passes through the second housing and is mounted to the second main shaft inside the second housing;

the operating mechanism is connected with and drives a lever to rotate by a second angle, and the lever drives the main shaft and the second main shaft to synchronously rotate by the first angle through the synchronous shaft.