JP2011146335A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a circuit breaker capable of facilitating arc to be readily blown out, at the opening/closing of a small current and capable of getting a high limit current break at short circuit breaking. <P>SOLUTION: The circuit breaker is provided with a fixed contact 23 mounted inside an insulation case, a movable contact 25 opposed to the fixed contact in a free contact and separation, an opening/closing mechanism driving the movable contact; an electromagnetic tripping unit 34 to open-and-separate the movable contact from the fixed contact; an arc generating chamber 40, in which arcs generated at the time of opening/separating of the movable contact are filled; and the circuit breaker is provided with an arc extinguishing unit 38 to extinguish arc inside the arc-generating chamber an insulation plate 1 sandwiching a fixed contact and a movable contact and is provided with an arc drive plate 2 at a prescribed interval 5, and is further provided with an insulation plate, with the fixed contact and the movable contact interposed, the inside width of the insulation plate being narrow, in a movable range of the movable contact and is made wider at an arc-running part, and a hole 4 is made that communicates with a gap 5 of the arc running part of the insulation plate. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a circuit breaker, and more particularly to a structure of a circuit breaker with improved breaking performance.

  In the conventional circuit breaker, in order to stably extinguish the arc at the time of interruption, an arc reflecting member for reflecting the arc in the arc traveling direction is provided on the arm together with the mover, and the contact where the arc is generated For example, Patent Literature 1 discloses that a pressure gradient is provided by forming an arc traveling path from a peripheral portion to an arc extinguishing device so that a cross-sectional area of the arc traveling path increases in the arc traveling direction. .

JP 2000-243208 A

  However, in the circuit breaker as described above, since the electromagnet part including the fixed contact is arranged on the opposite side of the switching mechanism including the mover, the first reflecting part of the arc reflecting member is provided. There is a limit to the length extending toward the fixed contact side, and when the opening / closing mechanism is separated, the distance between the movable contact and the fixed contact cannot be increased. For this reason, an arc generated between the movable and fixed contacts when the small current is opened and closed may be difficult to cut. As a result, contact wear due to arcs at the time of opening and closing becomes large, and there is a problem that the energization performance cannot be maintained during opening and closing durability.

  The present invention has been made in order to solve the above-described problems, and it is an object of the present invention to provide a circuit breaker that makes it easy to break an arc when a small current is opened and closed and that can cut off a high current limit when a short circuit is interrupted. It is what.

  A circuit breaker according to the present invention includes a fixed contact mounted inside an insulating casing, a movable contact contacting and separating from the fixed contact, an opening / closing mechanism for driving the movable contact, An electromagnetic trip device that activates an opening / closing mechanism in response to an electric current to separate a movable contact from a fixed contact, an arc generation chamber that is filled with an arc generated when the movable contact is separated, and the generation of the arc In a circuit breaker equipped with an arc extinguishing device for extinguishing an arc in a room, an insulating plate is provided with a fixed contact and a movable contact in between, and an arc driving plate is provided outside the insulating plate with a predetermined gap. The inner width of the insulating plate is narrow in the movable range portion of the movable contact and wide in the arc running portion, and a hole leading to the gap is provided in the arc running portion of the insulating plate.

  According to the present invention, since the insulating plate is disposed in the movable range portion where the movable contact opens and closes in proximity to the movable contact, the cross-sectional area of the arc at the time of opening cannot be greatly expanded in that direction, In addition, the arc resistance can be increased by cooling the arc in contact with the insulating plate, so that the switching performance with a small current can be improved. Since the arc drive plate can extend the arc between the contacts in the direction of the arc runner, the switching performance can be further improved.

In addition, in the arc running part, the insulating plate is provided with a stepped part so as to be farther from the movable contact than the movable range part of the movable contact, and a hole is provided in the arc running part. The generated gas is caused to flow from the hole of the insulating plate through the gap between the insulating plate and the arc drive plate to the vicinity of the contact point, further reducing the gas pressure near the arc extinguishing chamber and increasing the gas pressure near the contact point, thereby extinguishing the arc. Easy to move in the direction of the arc chamber. For this reason, the arc extinguishing time is shortened, the interruption performance is improved, and high current limiting interruption is possible.

It is a side view which shows a partially broken off state or trip operation state of the circuit breaker according to Embodiment 1 of the present invention. It is a side view which partially fractures | ruptures and shows the ON state of the circuit breaker which concerns on Embodiment 1 of this invention. It is the figure which looked at the cross section in alignment with the AA of FIG. 1 in the arrow direction. It is a top view (a), a side view (b), and a front view (c) showing the insulating plate in the first embodiment. It is the top view (a), side view (b), and front view (c) which show the arc drive plate in Embodiment 1. It is a perspective view which shows the state which combined the insulating plate, arc drive plate, and arc runner in Embodiment 1. FIG. FIG. 7 is an exploded perspective view of FIG. 6.

Embodiment 1 FIG.
As shown in FIGS. 1-3, the circuit breaker of this invention is equipped with the insulating housing which consists of the base 21 and the cover 22 which were all made from the synthetic resin material. In this insulating housing, a fixed contact 23 having a fixed contact 24 and a movable contact 25 having a movable contact 25a are provided facing each other. The movable contact 25 is rotatably supported by an arm 26, and the fixed contact 24 and the movable contact 25a can be contacted and separated by the rotation of the movable contact 25.

  The shaft 27 is a shaft serving as a rotation center of the arm 26 and the movable contact 25. The movable contact 25 is urged by the main spring 28 in a direction in which the movable contact 25 a is always separated from the fixed contact 24. The opening / closing mechanism is operated by a handle 29 that protrudes from the upper portion of the base 21. The handle 29 is biased counterclockwise by the reset spring 30. The operation link 31 in which a round bar is formed in a U shape has one end connected to the handle 29 and the other end engaged with a link engagement groove 32a of a latch 32 described later.

  The latch 32 pivotally supported by the shaft 27 includes 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, which will be described later, A trigger piece 32c is formed to receive a force in a direction to release the engagement between the operation link 31 and the link engagement groove 32a by the pressing force generated by the bending of the bimetal 33. The arm 26, the main spring 28, the handle 29, the reset spring 30, the operation link 31, the latch 32, and the like constitute an opening / closing mechanism.

A bimetal 33 is provided in the insulating housing. The bimetal 33 is heated and bent in the right direction in the drawing corresponding to the passing current. In addition, an electromagnetic trip portion 34 is further provided in the insulating housing. The plunger 36 is driven by the electromagnetic force applied to the electromagnet 35, and protrudes leftward in the drawing by the suction operation of the plunger 36. A rod 37 is provided. An overcurrent tripping device is formed by the bimetal 33 and the electromagnetic tripping portion 34. An arc-extinguishing device 38 having an arc-extinguishing plate 39 is provided in an arc generating chamber 40 including both fixed and movable contacts, and the arc generated between the fixed contact 24 and the movable contact 25a is It is guided to the runner 41 and is extinguished by the arc extinguishing device 38.

  The base 21 is provided with a stopper wall 21a projecting inward near the movable contact 25a, which is a position away from the arc generation chamber 40, and the shaft 27 which is the rotation center of the arm 26. The position of the open circuit when the is separated from the fixed contact 23 is regulated.

  FIG. 3 is an enlarged view of the cross section taken along the line AA in FIG. In the arc generation chamber 40, the fixed contact 23 and the movable contact 25 are located. The insulating plate 1 made of a substantially U-shaped synthetic resin is fixed to the base 21 so as to sandwich both the contacts. ing. As shown in FIG. 4, the insulating plates 1 located on both sides of the both contacts have a narrow interval between both sides in the movable range portion of the movable contact 25, while the movable contact 25 is movable in the arc running portion. A stepped portion 3 is provided on the inner side so as to be wider than the interval between the range portions, and a hole 4 is provided in the arc traveling portion. The insulating plate 1 is provided with a hole 6 for alignment when being attached to the base 21.

  On the outside of the insulating plate 1, an arc driving plate 2 made of a substantially U-shaped magnetic material is attached in close contact with the base 21. As shown in FIG. 5, a plurality of convex portions 7 are formed on both inner sides of the arc drive plate 2 to provide a gap 5 (see FIG. 3) between the arc drive plate 2 and the insulating plate 1. The gap 5 communicates with the arc traveling portion through the hole 4 and is opened in the vicinity of the fixed contact 24 and the movable contact 25a. The arc driving plate 2 is provided with a hole 8 for alignment when attached to the base 21.

  The relationship among the insulating plate 1, the arc drive plate 2, and the arc runner 41 will be described in more detail with reference to FIGS. An arc drive plate 2 is arranged so as to sandwich the insulating plate 1 connected in a U shape from both sides. Since the insulating plate 1 is in contact with the convex portion 7 protruding from the inner surface of the arc driving plate 2, a gap 5 is formed between them. An arc runner 41 is attached to the base 21, the insulating plate 1 is disposed so as to surround the arc runner 41, and the fixed contact 23 and the movable contact 25 are placed in a space surrounded by the insulating plate 1 and the arc runner 41. positioned. The gap 5 communicates with the hole 4 of the insulating plate 1, and the rear of the gap 5 is open to the arc runner 41 side, that is, in the vicinity of the fixed contact 24 and the movable contact 25a.

  In the circuit breaker having the above-described structure, when a small current equal to or lower than the rated current of the circuit breaker is opened and closed, the opening / closing mechanism is operated by the handle 29 and the movable contact 25 is separated from the fixed contact 23. At this time, an arc is generated between the fixed contact 24 and the movable contact 25a. Since the insulating plate 1 is disposed close to the movable contact 25 in the movable range when the movable contact 25 is opened, the arc at the time of opening is large on the insulating plate 1 side. It cannot be enlarged. Moreover, since the arc is cooled in contact with the insulating plate 1, the arc resistance is increased and the arc is extinguished to cut off the current, so that the switching performance with a small current is improved.

At the same time, the arc at the time of opening is expanded in the direction of the arc runner 41 by the magnetic flux induced by the U-shaped arc drive plate 2, that is, downward in FIG. Can be improved. Further, when interrupting a large short-circuit current, the electromagnetic trip portion 34 responds to the short-circuit current to trip the open / close mechanism, and the movable contact 25 is separated from the fixed contact 23 at high speed. At this time, similarly to the opening and closing described above, the arc generated at the time of opening is because the insulating plate 1 is disposed close to the movable contact 25 in the movable range when the movable contact 25 is opened. The cross-sectional area cannot be greatly increased to the 1 side of the insulating plate. Moreover, the arc is cooled in contact with the insulating plate 1 to increase the arc resistance. Further, since the magnetic flux induced by the U-shaped arc drive plate 2 is extended in the direction of the arc runner 41, that is, downward in FIG. The arc-extinguishing device 38 is reached, and the arc-extinguishing plate 39 is divided to extinguish the arc. For this reason, the arc extinguishing time is shortened and the interruption performance is improved.

  Further, the interval between the insulating plates 1 in the arc traveling portion is wider than the movable range portion of the movable contact 25 due to the step 3, and the hole 4 is formed in the arc traveling portion of the insulating plate 1. The arc drive plate 2 is provided with a gap 5 therebetween. The widening of the interval between the insulating plates 1 due to the step 3 reduces the gas pressure in the arc traveling portion. The hole 4 allows gas generated at the time of short-circuit interruption to flow into the vicinity of the fixed contact 24 and the movable contact 25a through the gap 5, further reducing the gas pressure near the arc extinguishing chamber 38, and reducing the gas pressure near the contact. Since the arc is easily moved in the direction of the arc extinguishing chamber 38, the arc extinguishing time is shortened, the interruption performance is improved, and high current limiting interruption is possible.

1 insulation plate, 2 arc drive plate,
3 steps, 4 holes,
5 Clearance 6 Alignment hole
7 convex part, 8 alignment hole,
21 base, 22 cover,
23 fixed contact, 24 fixed contact,
25 movable contact, 25a movable contact,
26 arms, 27 axes,
28 main spring, 29 handle,
30 reset spring, 31 operation link,
32 latch, 32a engaging groove,
32b trigger piece, 32c trigger piece,
33 Bimetal, 34 Electromagnetic tripping part,
35 electromagnets, 36 plungers,
37 rod, 38 arc extinguishing device,
39 arc extinguishing plate, 40 arc generating chamber,
41 Arc Runner.

Claims (5)

  A stationary contact mounted inside the insulating housing, a movable contact contacting and separating from the stationary contact, an opening / closing mechanism for driving the movable contact, and the opening / closing mechanism in response to an overcurrent. An electromagnetic trip device that operates and separates the movable contact from the fixed contact, an arc generation chamber filled with an arc generated when the movable contact is separated, and extinguishes the arc in the arc generation chamber In a circuit breaker provided with an arc extinguishing device, an insulating plate with the fixed contact and the movable contact interposed therebetween, and an arc driving plate with a predetermined gap outside the insulating plate are provided. The circuit breaker is characterized in that the width is narrow in the movable range portion of the movable contact and wide in the arc running portion, and a hole leading to the gap is provided in the arc running portion of the insulating plate.   2. The circuit breaker according to claim 1, wherein an inner width of the insulating plate is narrow in a movable range portion of the movable contact and wide in an arc traveling portion due to a step formed inside.   2. The circuit breaker according to claim 1, wherein the arc driving plate is provided with a convex portion, and the gap is formed by contacting the convex portion with the insulating plate.   The circuit breaker according to claim 1, wherein the gap is opened in the vicinity of the fixed contact and the movable contact.   2. The circuit breaker according to claim 1, wherein both the insulating plate and the arc driving plate are substantially U-shaped.

Images