CN111463079B

CN111463079B - Circuit breaker

Info

Publication number: CN111463079B
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: 2024-01-23
Anticipated expiration: 2039-01-18
Also published as: CN111463079A

Abstract

The invention provides a circuit breaker which comprises a breaking unit, a lever, a synchronous 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 moving contact is mounted on a spindle configured to rotate about a first axis of rotation. The lever is located outside the housing and configured to rotate about the second axis of rotation. The synchronizing shaft passes through the housing and extends parallel to the first and second rotating shafts, and is 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, is connected with and drives the lever to rotate, and the lever drives the main shaft to rotate through the synchronous shaft. According to the invention, as the shell is closed, the breaking and closing of the moving contact and the fixed contact are not interfered by the external environment; in addition, under a closed environment, when a short circuit occurs, larger air pressure extension arc is formed, and the arc is extinguished, 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 an excessive abnormal current flows in the circuit (e.g., an overload or short circuit) to protect the device and personnel. The circuit breaker includes a stationary contact and a moving contact, which are connected to the connection terminals, respectively, and form a normally closed break point. When the circuit is required to be disconnected, 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 an arc generated between the movable contact and the fixed contact.

Depending on the number of breakpoints, the circuit breaker may be a double-break circuit breaker and a single-break circuit breaker, respectively. The double-break circuit breaker comprises two moving contacts which are symmetrically arranged and simultaneously rotate, and are used for being respectively closed or opened with respective fixed contacts, and two groups of arc extinguishing chambers are needed. In contrast, the single-break circuit breaker only comprises a pair of moving contacts and a fixed contact, and only needs a group of arc extinguishing chambers, so that the size of the circuit breaker can be obviously reduced, and the cost can be reduced. However, in the single break circuit breaker of the prior art, the lower link of the operating mechanism is directly connected to the main shaft linked with the movable contact, and is limited by the volume of the inner space, the rotation angle of the main shaft is limited, and the opening distance is small; moreover, the moving contact and the stationary contact are generally exposed to the external environment, so that the breaking action is susceptible to the external environment.

Accordingly, it is desirable to provide a circuit breaker having improved breaking capacity.

Disclosure of Invention

The present invention aims to solve at least one of the problems caused by the prior art. More precisely, the object of the present invention is 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 arranged 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 at a first angle, the moving contact is contacted with the fixed contact at the first main shaft position, and the moving contact is broken with the fixed contact at the second main shaft position. The lever is located outside the housing and configured to rotate about a second axis of rotation that is parallel to the first axis of rotation. A synchronizing shaft passes through the housing and extends parallel to the first rotation shaft, the synchronizing shaft being mounted to the spindle on an inner side of the housing and to the lever on an outer side of the housing. 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 main shaft to rotate by the first angle through the synchronous shaft.

According to the invention, the moving contact and the fixed contact are positioned in the closed shell, and the breaking and closing of the moving contact and the fixed contact are not interfered by external environment; in addition, under a closed environment, the circuit breaker is favorable for forming larger air pressure when short circuit occurs, elongating the arc and being favorable for extinguishing the arc, thereby improving the breaking performance of the circuit breaker.

In the first aspect, the first rotation axis and the second rotation axis may be misaligned, and the first rotation axis is closer to the synchronization axis than the second rotation axis such that the first angle is greater than the second angle. In this case, the lever which rotates at a small angle can be used to actuate the main shaft to rotate at a larger angle, the opening distance of the circuit breaker is increased, the arc is extinguished rapidly, and the safety of the circuit breaker is improved.

Optionally, 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 at 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. 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 axis of rotation and the second axis 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, 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 drive the main shaft to rotate by utilizing the two synchronous shafts, so that the action stability of the moving contact is improved, the load of the synchronous shafts 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 rotation shaft and the second rotation shaft.

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

Optionally, the backup protection device may include: a stationary armature fixed to the first terminal; a moving armature fixed to a moving armature bracket fixed to the trip synchronous shaft; a spring that applies a spring force to keep the stationary 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 moves towards the static armature against the spring force 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 include only a single pair of the moving contact and the fixed contact. In this case, the present invention provides a single-break circuit breaker having advantages of compact size and high reliability.

Optionally, the circuit breaker may further include a second breaking unit including a second moving contact, a second fixed contact, a second main shaft, and a closed second housing, where the second moving 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 each be used to break the current of the individual phases, and a common synchronization shaft may drive the plurality of breaking units to be synchronously broken or closed.

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

Drawings

The following drawings are included to better demonstrate some embodiments of the invention, together with the description herein, for the purpose of illustrating the various features and advantages thereof, as defined in the claims. Like reference numerals designate identical or corresponding parts throughout the several views.

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 broken state;

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

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

Reference numerals

1. Synchronous shaft of shell 10

2. Second synchronous shaft of moving contact 11

3. Backup protection device for static contact 12

4. Spindle 121 static armature

5. First connecting terminal 122 moving armature

6. Second connecting terminal 123 spring

7. Lever 124 moving armature bracket

71. Chute 13 trip bar

8. Operating mechanism 14 trip synchronizing shaft

81. Handle 15 support

82. Copper knitting wire of upper connecting rod 16

83. Lower connecting rod 17 arc extinguishing chamber

84. First lever A first rotating shaft

85. Second rod B second rotating shaft

86. Third pole U breaking unit

9. Rivet

Detailed Description

A circuit breaker may be installed in a circuit via two terminals, and when an operational fault (e.g., a short circuit or an overcurrent) is detected, the current in the 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 the three-phase circuit. The three breaking units U may have the same structure so as to be interchangeable. The breaking unit U is installed by a base and a cover of the circuit breaker. In other embodiments, the circuit breaker may include other numbers (e.g., one, two, four) of breaking units that are identical or similar in structure.

As shown in fig. 1, each breaking unit U has a closed casing 1, which can be formed by bolting two half-casings. By "closed" is meant that the housing 1 substantially isolates the internal moving contacts, stationary contacts, etc. from the external environment, unless small-sized openings are provided for specific purposes, for example, holes or slots may be provided in the side walls of the housing 1 for the passage of at least one synchronizing shaft 10. The moving contact, the fixed contact, the arc extinguishing chamber, the main shaft and other parts of the breaking unit U are all positioned in the closed shell 1. Thereby, the housing 1 can protect the internal electric components from the external adverse effects, and particularly, when the moving contact and the fixed contact are separated, the arc formed therebetween is not affected by the external environment, and can be reliably extinguished by the arc extinguishing chamber. Moreover, the closed shell 1 limits the internal gas, is favorable for forming larger air pressure during short circuit, elongating the arc and being favorable for extinguishing the arc, thereby improving the breaking performance of the circuit breaker.

The breaker is provided with an operating mechanism 8 which is used for driving a main shaft positioned in the shell 1 to rotate and then driving a moving contact to rotate so as to realize breaking. The operating mechanism 8 can be operated to realize manual breaking, and the tripping device can also be utilized to realize automatic breaking. In order to mount the operating mechanism 8 on the outside of the case 1, the circuit breaker shown in fig. 1 is provided with two brackets 15 respectively mounted on both side walls of the breaking unit U in the middle, 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 to rotate via at least one synchronizing shaft. As shown in fig. 1, the synchronizing shaft 10 may extend to the inner sides of the three breaking units U, and be respectively mounted to the main shafts inside the respective breaking units U, so that the three breaking units U may be synchronously opened and closed. Near the bracket 15, the synchronizing shaft 10 is connected to a lower link of the operating mechanism 8 for receiving a driving force.

Fig. 2 and 3 show a closed state and a broken state of the circuit breaker according to the first embodiment of the present invention. The front portion of the housing 1 is not shown in order to show the internal structure. The moving contact 2 is mounted 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 wiring terminal 5 through a copper braided wire 16 which is flexibly deformed and moved; 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, the circuit breaker remains in the closed condition shown in fig. 2, wherein the moving contact 2 is in a first angular position extending downwards and in contact with the stationary contact 3, allowing the current to flow through the first terminal 5 and the second terminal 6. In an abnormal situation, when the current in the circuit exceeds a threshold value, for example an overload or short-circuit fault occurs in the circuit, the operating mechanism 8 is actuated manually or automatically and drives the spindle 4 to rotate, causing the moving contact 2 to rotate to the second angular position extending upwards as shown in fig. 3 and to disengage from the stationary contact 3. The arc extinguishing chamber 17 is arranged near the moving contact 2 and the fixed contact 3, so that an electric arc can be extinguished rapidly, 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 83. The handle 81 is connected to the upper link 82 via an energy storage spring, and the lower end of the upper link 82 is rotatably connected to the upper end of the lower link 83, and the lower end of the lower link 83 is rotatably connected to the right end of the lever 7. When the handle 81 is rotated from the closed position shown in fig. 2 to the open position shown in fig. 3, the energy storage spring releases potential energy, causing the upper link 82 to rotate clockwise by a certain angle, driving the lower link 83 to rotate counterclockwise by a certain angle, and then pulling the right end of the lever 7 to move upward 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 83, and in this first embodiment, the lever 7 and the lower link 83 are rotatably connected by a rivet 9. In other embodiments, other rotational attachment structures such as pins may also 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 so as to be movable along the slide groove 71 with the swinging 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 is 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 about the second rotation axis B by the second angle, the slide groove 71 pushes the synchronizing shaft 10 to move, thereby driving the main shaft 4 to rotate about the first rotation axis a by the first angle.

In this first embodiment, the first rotation axis a of the spindle 4 and the second rotation axis B of the lever 7 do not coincide, but are spaced apart by a distance. Further, the second rotation axis B is not located at the intermediate position of the lever 7, but is closer to the rivet 9 than the slide groove 71. In this case, on the lever 7, the arm of force of the rivet 9 is smaller than that of the synchronizing shaft 10, and thus, the synchronizing shaft 10 moves downward by a greater distance than the rivet 9 moves upward. Further, the second rotation axis B of the lever 7 is arranged farther from the synchronization 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 greater than the rotation angle of the lever 7. Therefore, compared with the situation that the first rotating shaft A and the second rotating shaft B are overlapped, the embodiment realizes a larger rotating angle of the main shaft 4 by utilizing the smaller ascending stroke of the rivet 9, so that the distance (called as an opening distance) between the moving contact 2 and the fixed contact 3 in the breaking state is larger, and better breaking effect is realized. Moreover, this design is also advantageous for reducing the volume of the circuit breaker, since there is no need to design a more complex, larger-volume operating mechanism 8 in order to meet the larger lifting stroke 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, bracket, etc. of fig. 4 removed to better show the internal structure. The second embodiment is substantially identical to the first embodiment described above, with the main difference 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. The second synchronization shaft 11 likewise extends through the housing 1 and is parallel to the first rotation axis a and the second rotation axis B, in particular the second synchronization shaft 11 and the first synchronization shaft 10 are arranged symmetrically with respect to the first rotation axis a. On the inside of the housing 1, a second synchronizing shaft 11 is mounted to another position 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 two symmetrically arranged synchronizing shafts 10 and 11, so that the main shaft 4 and the moving contact 2 rotate more smoothly. In addition, the rotation moment 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, during the rotation of the lever 7, the distance of the synchronization shaft 10 with respect to the lever 7 is unchanged, and thus the synchronization 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, an outer side of the housing 1 is provided with a bracket 15 which can support a portion of the second rotation shaft B to provide a fulcrum for rotation of the lever 7. Further, a guide groove may be provided on the bracket 15 to guide the synchronizing shafts 10 and 11 to smoothly rotate.

Another difference between the second embodiment and the first embodiment described above is that a back-up 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 breaking of the circuit breaker in case of detecting an overcurrent. Specifically, the backup protection device 12 includes a stationary armature 121 and a movable armature 122, the stationary armature 121 being fixed to the first connection terminal 5, the movable armature 122 being fixed to a movable armature bracket 124, and a spring 123 being disposed between the stationary armature 121 and the movable armature 122 for biasing the two 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 synchronization shaft 14 are coaxially coupled. As shown in fig. 5, the components of the backup protection 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 connecting terminal 5 exceeds the threshold value, the movable armature 122 moves towards the fixed armature 121 against the spring force of the spring 123 under the action of electromagnetic force, and drives the movable armature bracket 124 and the tripping synchronous shaft 14 to rotate. The trip synchronizing shaft 14 passes through the housing 1, and is fixedly connected to and drives the trip bar 13 outside the housing 1. It should be noted that the backup protection described herein is merely exemplary, and that other previously known or future developed backup protection may be employed by those skilled in the art.

The operating mechanism 8 can be locked at the closed position to keep the movable contact 2 and the fixed contact 3 closed; meanwhile, the movable contact 2 and the fixed contact 3 can be tripped and rotated to the breaking position under the actuation of the tripping rod 13, so that the breaking of the movable contact 2 and the fixed contact 3 is promoted. 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 pressing 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 may exert a latch retention force on the third lever 86 via the second lever 85, holding the handle 81 in the closed position. When the trip bar 13 rotates, the upper end thereof pushes the lower end of the first lever 84 so that the first lever 84 rotates. 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 applied to the third lever 86. At this time, the handle 81 is rotated to the breaking position shown in fig. 5 by the energy storage spring, and the lever 7 is rotated via the upper link 82 and the lower link 83 as described above, thereby causing the main shaft 4 to rotate, and the movable contact 2 and the stationary contact 3 are separated. It should be noted that the latching mechanisms described herein are merely exemplary and that other latching mechanisms previously known or later developed may be employed by those skilled in the art.

Some embodiments for implementing the present invention have been described in detail above, but it should be understood that these embodiments are merely for purposes of example, and are not intended to limit 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. Those skilled in the art can make numerous modifications to the above-described embodiments, which fall within the scope of the present invention, given the teachings of the present 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 positioned on the inner side of the shell, the moving contact is arranged 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 at a first angle, the moving contact is contacted with the fixed contact at the first main shaft position, and the moving contact is broken with the fixed contact 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 a hole or a groove provided on a side wall of the housing for the synchronizing shaft to pass therethrough and extending in parallel with the first rotation 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 first position of 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 second position of the lever, is positioned on two sides of the second rotating shaft and is configured to drive the lever to rotate by a second angle, so that the lever drives the main shaft to rotate by the first angle through the synchronous shaft.

2. The circuit breaker according to claim 1, wherein,

the first and second axes of rotation are misaligned and the first axis of rotation is closer to the synchronization axis than the second axis of rotation such that the first angle is greater than the second angle.

3. The circuit breaker according to claim 2, wherein,

the first end of the lever is rotatably connected to a 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 positioned on two sides of the second rotating shaft, the synchronous shaft is received in the sliding groove, and when the lever rotates by a second angle, the synchronous shaft slides along the sliding groove and drives the main shaft to rotate by a first angle.

4. A circuit breaker according to claim 3, wherein,

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 are coincident such that the first angle is equal to the second angle.

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

the second synchronizing shaft is arranged through the shell and extends parallel to the synchronizing shaft, is mounted to the main shaft at the inner side of the shell, and passes through the first end of the lever and the lower connecting rod of the operating mechanism at the outer side of the shell, so that the first end of the lever and the lower connecting rod of the operating mechanism are rotatably connected.

7. The circuit breaker according to claim 6, wherein,

the second end of the lever has a circular aperture within which the synchronizing shaft is received, the synchronizing shaft and the second synchronizing shaft being symmetrical about a first axis of rotation.

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 the housing;

and a trip synchronizing shaft which is arranged through the shell, wherein the trip synchronizing shaft is arranged on the inner side of the shell, the trip synchronizing shaft is arranged on the outer side of the shell, the trip synchronizing shaft is arranged on a trip rod, and when the current flowing through the circuit breaker exceeds a threshold value, the backup protecting device trips the operating mechanism through the trip rod.

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

the breaking unit only comprises a single pair of moving contact and fixed 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, wherein 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 positioned at the outer side of the second housing, and the synchronizing shaft passes through the second housing and is mounted to the second main shaft at the inner side of 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.