JP4489930B2 - Circuit breaker - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a circuit breaker, and more particularly to an improvement of a circuit breaker that reliably releases a contact when an overcurrent flowing through a breaker circuit is interrupted.
[0002]
[Prior art]
Generally, there is a circuit breaker as a device that interrupts the flow of an electric circuit due to a fault current such as a short circuit current, but the electromagnet is activated by the overcurrent flowing through the circuit breaker circuit to release the contact. Is cut off. In such a circuit breaker, an arc extinguishing device is housed to extinguish an arc generated when the contact is opened so that the interruption time does not become long.
As a conventional circuit breaker, for example, there is a circuit breaker (hereinafter referred to as “conventional device”) disclosed in Japanese Patent Laid-Open No. 10-172409 shown in FIG. The insulating casing 20 in such conventional mounting includes a base 21 and a cover 22 formed of a synthetic resin material. The interruption circuit is provided with a fixed contact 23, a fixed contact 24 fixed to the fixed contact 23, and a movable contact 25 having a movable contact 25 a facing and separating from the fixed contact 24. Yes. An arm 26 integrally supports the movable contact 25, and is formed with a U-shaped groove 26a, a stopper locking portion 26b, and a long hole 26c with which a shaft 27 described later is engaged.
[0003]
Reference numeral 27 denotes an axis serving as a rotation center of the arm 26 and the movable contact 25, and is supported by an insulating casing. 28 is a main spring that is stretched so as to always urge the movable contact 25 in the direction in which the movable contact 25 is always released from the fixed contact 24, 29 is a handle that is made of synthetic resin and can be opened and closed from the outside, and 30 is a counterclockwise rotation of the handle 29. A reset spring 31 for urging the rod is an operation link formed by bending a round bar material into a U shape, and one end engages with a handle 29 and the other end engages with a link engagement groove 32a of a latch 32 described later. To do. The handle 29 includes a handle portion 29 b that protrudes outside the insulating housing 20 and a protrusion portion 29 c that connects the operation link 31.
[0004]
32 is a latch pivotally supported by the shaft 27, a link engaging groove 32a that engages with the other end of the operation link 31, a trigger piece 32b that receives the pressing force of the rod 37 of the electromagnetic tripping portion 34 to be described later, A trigger piece 32c that receives a force in a direction to release the engagement between the operation link 31 and the link engagement groove 32a by a pressing force due to the bending of the bimetal 33 described later is formed. A return spring 32d is provided between the arm 26 and the latch 32 so as to urge the latch 32 counterclockwise with respect to the arm 26 at all times. The other end of the operation link 31 fitted in the U-shaped groove 26a is clamped by the link engaging groove 32a of the latch 32 by the spring force of the spring 32d and is in a locked state. Then, the movable contact 25a is elastically contacted with the fixed contact 24 to form a cutoff circuit (state shown in FIG. 5).
Thus, the arm 26, the main spring 28, the handle 29, the reset spring 30, the operation link 31, and the latch 32 constitute an opening / closing mechanism.
[0005]
Reference numeral 33 denotes a bimetal that is heated and bent in the right direction in FIG. 5 in response to the energization current. Reference numeral 34 denotes an electromagnetic trip device. The plunger 36 is driven by electromagnetic force generated by energization of the electromagnet 35, and the plunger 36 is attracted. It has the rod 37 which protrudes in the left direction in FIG. 9 by operation | movement. The bimetal 33 and the electromagnetic trip device 34 form an overcurrent trip device. Reference numeral 38 is an arc extinguishing device, and 39 is an arc extinguishing plate of the arc extinguishing device 38. Reference numeral 40 denotes an arc generation chamber including the fixed contact 24 and the movable contact 25, and the arc generated when the movable contact 25 is opened is filled. An arc runner 41 guides the arc toward the arc extinguishing device 38.
[0006]
In the circuit breaker configured in this way, when a short-circuit current flows in the electric circuit, the electromagnet 35 of the electromagnetic trip device 34 senses and works, the plunger 36 is attracted, and the rod 37 associated therewith is moved to the left. Move in the direction. Then, the trigger piece 32b is pressed by the rod 37, and the latch 32 rotates clockwise against the spring force of the return spring 32d. The other end of the operation link 31 fitted in a locked state by the link engagement groove 32a in the U-shaped groove 26a is free with respect to the arm 26 as the latch 32 rotates clockwise. It becomes a state. Therefore, the arm 26 is forcibly rotated clockwise about the shaft 27 by the spring force of the main spring 28 as an opening mechanism to perform a tripping operation. Thus, the movable contact 25 is separated at a high speed and performs a blocking operation.
[0007]
[Problems to be solved by the invention]
However, in the above-described conventional device, when a large current such as a short-circuit current flows in the electric circuit and the opening / closing mechanism is opened, the arm 26 moves suddenly by the spring force of the main spring 28, so it collides with the stopper 42 and bounces. Come back. Since the bounced arm 26 is not structured to prevent movement with respect to the latch 32, it repels until it hits the tip of the rod 37 regardless of the latch 32. At that time, the separation distance between the movable contact 25a and the fixed contact 24 is shortened, and the arc that has moved toward the arc extinguishing chamber 38 returns again between the movable contact 25 and the fixed contact 23, and the movable contact 25a An arc tends to stay between the fixed contact 24 and the fixed contact 24.
[0008]
For this reason, there existed a malfunction that the residence time of an arc became long and the interruption | blocking time became long and the interruption | blocking defect became easy to occur.
Further, since the arc residence time becomes longer, there is a problem that the consumption of the movable contact 25a and the fixed contact 24 is increased.
[0009]
The present invention has been made to solve the above-described problems, and prevents the arm from bouncing off during the overcurrent tripping operation of the circuit breaker, thereby setting the separation distance between the contacts to a predetermined value. An object of the present invention is to obtain a circuit breaker that shortens the dwell time of the arc generated between the contacts by performing the above-described operation and reliably cuts off, and consumes less of the movable contact and the fixed contact.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration. That is, the circuit breaker of the present invention drives an insulating casing, a fixed contact mounted in the insulating casing, a movable contact facing and separating from the fixed contact, and the movable contact. An opening / closing mechanism having an arm and a latch, a stopper provided on an insulating housing and abutting the arm to determine the maximum opening position of the movable contact, and operating the latch of the opening / closing mechanism in a tripping position in response to an overcurrent In a circuit breaker having an electromagnetic trip device having a plunger, the plunger and the latch have engagement portions for engaging with each other, and these engagement portions are operated by an electromagnetic trip device to be opened and closed. Even when the movable contact is released by the arm and the arm collides with the stopper, they are engaged with each other. While the plunger is maintained in the operating position, the latch is pulled out and held in the movable position. There is a circuit breaker, characterized in that it prevents rebounding to the closed position.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on the embodiment shown in FIGS. In addition, the same code | symbol as what was used for the same thru | or equivalent member and part as the conventional circuit breaker shown in FIG. 5 is attached | subjected, and description is abbreviate | omitted.
[0012]
FIG. 1 is a front view showing a part of a circuit breaker according to an embodiment of the present invention with a part cut away, and shows a state where the circuit breaker is in a closed state. FIG. 2 is a front view showing when the circuit breaker of FIG. 1 is in an open circuit state. FIG. 3 is a front view showing a state in which the circuit breaker of FIG. FIG. 4 is a front view showing a state where the circuit breaker of FIG. 1 has tripped and the arm is restrained.
[0013]
In FIG. 1, the circuit breaker includes a base 21 and a cover 22, and includes an insulating casing 20 made of a synthetic resin material. A fixed contact 23 is mounted inside the insulating housing 20, and a fixed contact 24 is fixed to the fixed contact 23. In addition, a movable contact 25 having a movable contact 25a that contacts and separates from the fixed contact 24 is provided, and the movable contact 25 is integrally supported by a movable contact holder 25H.
[0014]
An arm 26 is also provided in the insulating housing 20 so as to be substantially horizontal through a shaft 27. A movable contact holder 25H is pivotally supported at one end of the arm 26, and a U-shaped groove 26a as a first engaging groove for removably receiving the other end of the operation link 31 is formed at the other end of the arm 26. Has been. Further, the arm 26 is formed with a stopper engaging portion 26b that is in contact with a latch 32 described later and is in contact with a stopper 21a provided on the base 21 by bending, for example, by pressing. A main spring 28 is contracted between the arm 26 and the insulating housing 20, and the arm 26 is always urged to rotate clockwise by the urging force of the main spring 28, whereby the movable contact 25 is fixed to the fixed contact. It is energizing in the direction of always separating from 24. The stopper locking portion 26b rotated by the rotation urging force contacts the stopper 21a, whereby the maximum rotation angle position of the arm 26, that is, the maximum opening position of the movable contact 25 is defined. Contact name A over arm 26 and movable contact 25 is rotated as the pivot around an axis 27 supported by the insulating housing 20.
[0015]
The circuit breaker also has a handle 29 that is made of synthetic resin and can be opened and closed from the outside. The handle 29 has a base portion 29a, a handle portion 29b that protrudes from the base portion 29a to the outside of the insulating housing 20, and a postscript. It is comprised with the protrusion part 29c which connects the operation link 31 to perform. A reset spring 30 is provided to urge the handle 29 counterclockwise. The operation link 31 is formed by bending a round bar into a U shape. One end of the operation link 31 is engaged with the protruding portion 29c of the handle 29, and the other end is formed in a U-shaped groove 26a and a latch 32 described later. It is received and held in a link engagement groove 32a as a second engagement groove.
[0016]
On the other hand, the latch 32 is also supported coaxially with the arm 26 via the shaft 27, and at one end thereof is an engaging portion 32b that engages with the plunger 36 of the electromagnetic trip device 34 that is attracted in response to overcurrent. However, the other end is provided with a link engagement groove 32a for holding the other end of the operation link 31 received in the U-shaped groove 26a. A small gap exists between the other end of the latch 32 and the stopper engaging portion 26b at the other end of the arm 26 in the normal state shown in FIG. The operation link 29 is disengaged from the link engagement groove 32a by rotating to a position where the 32 abuts against the stopper locking portion 26b.
[0017]
On the other hand, in the vicinity of the electromagnetic trip device 34, a bimetal 33 that is heated and curved in the left direction in FIG. A trigger piece 32c that receives a force in a direction to release the engagement between the operation link 31 and the link engagement groove 32a by rotating the link 42 counterclockwise about the shaft 43 by the pressing force due to the bending displacement of the bimetal 33 is provided. Is formed. The movable contact holder 25H, the arm 26, the main spring 28, the handle 29, the reset spring 30, the operation link 31, and the latch 32 constitute an opening / closing mechanism 300.
[0018]
Further, the electromagnetic trip device 34 has a plunger 36 that is attracted and driven by an electromagnetic force generated by energizing the electromagnet 35. The bimetal 33 and the electromagnetic trip device 34 form an overcurrent trip device. An arc extinguishing device 39 for extinguishing an arc generated between the contacts is provided with an arc extinguishing plate 39. The engagement portion 42 a is pushed by the bending of the bimetal 33, and a link 42 that rotates counterclockwise about the shaft 43 is also provided.
[0019]
If an overcurrent at the closed position shown in FIG. 1 flows through the electromagnetic trip device 34, the plunger 36 in its initial moves Oite left in FIG. The protrusion 36 a of the plunger 36 hits the engaging portion 32 b of the latch 32, and the latch 32 is rotated clockwise about the shaft 27. The arm 26 that has been fitted into the U-shaped groove 26 a of the arm 26 and restrains the operation link 31 by the rotation of the latch 32 has the link engaging groove 32 a of the latch 32 as a locking means from the operation link 31. In order to disengage, it is released from the restraining force by the operation link 31 and is rotated clockwise around the shaft 27 by the biasing force of the main spring 28. At this time, the suction force from the plunger 36 is also applied to the urging force of the main spring 28, and the arm 26 rotates in a state where the latch 32 is brought into contact with the stopper locking portion 26b of the arm 26 (FIG. 4).
[0020]
Since the movable contact holder 25H rotates integrally with the arm 26, the movable contact 25 is separated from the fixed contact 23 as shown in FIG. At this time, an arc is generated between the movable contact 25 and the fixed contact 23. At this time, since the arm 26 moves clockwise around the shaft 27 at high speed, the stopper locking portion 26b collides with the stopper 21a and rotates counterclockwise around the shaft 27 by the repulsion operation. try to.
[0021]
However, the arm 26 comes into contact with the latch 32 at the stopper locking portion 26b, but an arc is generated between the movable contact 25 and the fixed contact 23, and is electrically connected by this arc. For this reason, the current continues to flow through the electromagnet 35, and the plunger 36 is attracted to the electromagnet 35 and kept in the operating position. On the other hand, since the protruding portion 36a of the plunger 36 and the engaging portion 32b of the latch 32 are kept engaged, the latch 32 is in a state in which the rotation in the counterclockwise direction is locked by the plunger 36. The arm 26 is restrained and restrained from rotating counterclockwise. After the circuit is shut off, the stopper engaging portion 26b is pressed against the stopper 21a by the urging force of the main spring 28 as shown in FIG.
[0022]
When resetting the circuit breaker, that is, returning to the closed position again, as shown in FIG. 2, the handle 29 is turned counterclockwise to the closed position, and the other end of the operation link 31 is connected to the U-shaped groove 26a of the arm 26. And received in the link engaging groove 32a of the latch 32. At this time, the operation link 31 is received in the U-shaped groove 26a by pushing open the link engaging groove 32a against the weight of the latch 32. Once received, the other end of the operation link 32 is captured by the arm 26 and the latch 32 so as not to be pulled out by the weight of the latch 32 again. In this state, even if the handle 29 is forcibly rotated clockwise against the urging force of the reset spring 30, it can be returned to the normal use state and used in the closed position as shown in FIG.
[0023]
As described above, according to the circuit breaker of the present invention, when an overcurrent flows, the arm 26 is prevented from rotating counterclockwise, that is, rebounded, so that the movable contact 25 and the fixed contact 23 are Since the opening distance is not reduced, the dwell time of the arc generated between the movable contact 25 and the fixed contact 23 is shortened, smoothly moves in the direction of the arc extinguishing chamber 38 and is extinguished, and is shut off in a short time. As a result, there are fewer interruption failures. Further, since the arc residence time is shortened, there is an effect that consumption of the movable contact 25a and the fixed contact 24 can be reduced. Further, the arm 26 can utilize the self-weight of the latch 32 by arranging the latch 32 so as to be substantially horizontal above the electromagnetic trip device 34 in the normal use state. Therefore, the arm 26 and the latch 32 can be used. It is not necessary to provide the return spring 32d as in the conventional device. As a result, the engaging portion 32b does not have to be provided on the moving axis of the plunger 36 as in the above-described conventional device, and therefore, the lateral width is small, and there is an operational effect that a compact circuit breaker having a structure can be obtained.
[0024]
【The invention's effect】
A circuit breaker according to the present invention includes an insulating housing, a fixed contact mounted in the insulating housing, a movable contact that contacts and separates from the fixed contact, an arm that drives the movable contact, and An opening / closing mechanism having a latch; a stopper provided on an insulating housing that contacts the arm to determine the maximum opening position of the movable contact; and a plunger that operates the latch of the opening / closing mechanism in response to an overcurrent to operate to the release position. In a circuit breaker having an electromagnetic trip device, the plunger and the latch have engagement portions for engaging with each other, and these engagement portions are movable by an opening / closing mechanism when the electromagnetic trip device is operated. When the contacts are released and the arms collide with the stopper, they are engaged with each other. While the plunger is maintained in the operating position, the latch is pulled out and held in the disengaged position, so that the movable contact is closed. position A circuit breaker, characterized in that it prevents rebounding.
[0025]
Therefore, even if the arm is bounced off by the stopper, the reverse rotation of the arm is stopped by the plunger held in the operating position by the arc current, so that the separation distance between the movable contact and the fixed contact can be reliably maintained. As a result, the time during which the arc stays between the movable contact and the fixed contact is shortened, and the failure of interruption is reduced, and the consumption of the movable contact and the fixed contact is reduced.
[Brief description of the drawings]
FIG. 1 is a front view showing a part of a circuit breaker according to an embodiment of the present invention with a part cut away, and showing a state where the circuit breaker is in a closed state.
FIG. 2 is a front view showing the circuit breaker of FIG. 1 in an open circuit state.
FIG. 3 is a front view showing the circuit breaker of FIG. 1 in an initial state of tripping operation;
4 is a front view showing a state in which the circuit breaker of FIG. 1 is tripped and the open / close mechanism is restrained. FIG.
FIG. 5 is a partially cutaway front view showing a conventional circuit breaker.
[Explanation of symbols]
20 Insulating housing, 21a Stopper, 23 Fixed contact, 25 Movable contact, 26 Arm, 26a Stopper, 32 Latch, 32b Engagement part, 34 Electromagnetic trip device, 36 Plunger, 36a Engagement part, 300 Opening / closing mechanism

Claims (1)

An insulating housing, a fixed contact mounted in the insulating housing, a movable contact facing and separating from the fixed contact, an opening / closing mechanism having an arm and a latch for driving the movable contact; An electromagnetic puller having a stopper that is provided in an insulating housing and that contacts the arm to determine the maximum opening position of the movable contact, and a plunger that operates the latch of the opening and closing mechanism to the tripping position in response to an overcurrent. In a circuit breaker equipped with a disconnecting device,
The arm includes a stopper locking portion with which the latch contacts,
The plunger and the latch have engagement portions for engaging with each other, and the engagement portions are operated by operating the electromagnetic tripping device to open the movable contact by the opening / closing mechanism. Even when they collide with the stopper, they are engaged with each other, and while the plunger is maintained in the operating position, the latch is held in the releasing position,
A circuit breaker characterized by preventing the movable contact from bouncing back to the closed position.

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