JP2012069391A - Circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit breaker which has high breaking performance over a range from a small current to a large current.SOLUTION: A circuit breaker comprises: a case for accommodating a movable contact maker having a movable contact, a stationary contact maker having a stationary contact, and an arc-extinguishing grid plate provided at a position opposed to a locus path of the movable contact maker; and a cover. The circuit breaker includes: a pair of shield plates fitted to the cover and having a locus path of the movable contact maker sandwiched behind the tip face of the movable contact maker from both left and right sides without sandwiching at least part of the tip part of the movable contact maker; and an arc counter plate disposed at the tip on the tip side of the movable contact maker of the shield plates on a perpendicular direction side relative to the locus face of the movable contact maker and having an arc counter surface. The shield plates and the arc counter plate are disposed apart from the stationary contact maker.

Description

  The present invention relates to a circuit breaker that can be used as a circuit breaker for wiring, an earth leakage breaker, and the like, and particularly relates to a configuration of a current breaker.

  In a conventional circuit breaker such as a circuit breaker for wiring, the arc generated between the movable contact paired with the fixed contact is quickly extinguished when the direction perpendicular to the track path of the movable contact is set to the left-right direction. In order to achieve this, a pair of slit arc extinguishing plates made of a polymer material that sandwiches the fixed contact and the movable contact from side to side is arranged between the fixed contact and the movable contact at the time of current interruption such as a short circuit current. A circuit breaker is known in which a generated arc is quickly extinguished by a slit effect (arc compression / cooling) to limit the current.

  For example, in the prior art of this circuit breaker, in order to prevent re-ignition immediately after current interruption, a slit arc extinguishing plate is arranged over the entire length of the opening movement path, and the slit extinguishing between the wall surfaces is arranged. The arc space is divided into a region close to the fixed contact and a region on the opening side ahead of the region, and a narrow gap in the region close to the fixed contact is set narrowly. There has been known a structure that secures an insulation distance between the movable contact and the narrow arc extinguishing plate by enlarging the narrow gap. (For example, see Patent Document 1)

  In addition, in the conventional circuit breaker of the slit arc extinguishing method using the slit effect, a slit arc extinguishing plate with various other improvements for improving the current limiting performance is mounted in the arc extinguishing chamber. ing. For example, in the circuit breaker shown in FIG. 5, two shielding plates 21A protruding from the cover 2A and sandwiching the tip of the movable contact 41 to which the movable contact 42 is attached are formed integrally with the cover 2A. Then, the movable contact 41 and the movable contact 42 in the open position are sandwiched between the left and right sides by the shielding plate 21 </ b> A, thereby generating between the fixed contact 32 of the fixed contact 31 and the movable contact 42 of the movable contact 41. Thus, the slit effect is achieved without using a slit arc extinguishing plate (see, for example, Patent Document 2).

Japanese Patent Laying-Open No. 2008-66171 (page 4, FIG. 1) JP-A-9-92123 (page 3, FIG. 1)

  The above-described conventional circuit breaker using the slit arc extinguishing system has the following problems when the current is interrupted.

  In the circuit breaker having the slit arc extinguishing plate structure disclosed in Patent Document 1 described above, the slit arc extinguishing plate is arranged over the entire length of the opening moving path, that is, the tip of the movable contact and A slit arc extinguishing plate is placed across the entire movable contact, which can effectively demonstrate the slit effect at the time of current interruption, but in the case where metal melt or soot adheres to the movable contact or the movable contact It is difficult to secure an insulation distance between the slit arc extinguishing plate in contact with the fixed contact and the movable contact, and there is a problem that current limit performance is deteriorated due to re-ignition after current interruption.

  Further, in the slit arc extinguishing circuit breaker disclosed in Patent Document 2 described above, as shown in FIG. 5, the tip of a movable contact 41 to which a movable contact 42 is attached facing downward from the cover 2A. The two shielding plates 21 </ b> A protruding across the portion are arranged, and the end of the shielding plate 21 </ b> A on the fixed contact 31 side does not extend to the fixed contact 31. Therefore, since a space is provided between the shielding plate 21A and the stationary contact 31, it is easy to ensure an insulation distance, and re-ignition after current interruption can be prevented. On the other hand, however, the slit effect is difficult to cut off at high currents that require a high voltage between the poles (arc voltage) at low currents or when the current is cut off. There is.

  In this way, when it is difficult to ensure sufficient cut-off performance in a high voltage circuit (for example, AC 690 V, AC 600 V, etc.) only by the slit effect, the cut-off performance is improved by using arc cooling by the arc extinguishing grid plate. Is important.

  However, at the time of a small current at which the electromagnetic force is weakened, or when the current is interrupted by several tens of KA class where the arc is easily stuck, it is difficult to push the arc into the arc extinguishing grid plate. However, there was a problem that the current limiting performance could not be secured sufficiently.

  The present invention has been made in order to solve the above-described problems, and there is no deterioration of the current limiting performance due to re-ignition, and an arc extinguishing grid even at a small current or a large current of several tens of KA class. An object of the present invention is to provide a circuit breaker that can be easily pushed into a board.

  A circuit breaker according to the present invention includes a movable contact provided with a movable contact, a fixed contact provided with a fixed contact, and an arc extinguishing grid plate provided at a position facing the track path of the movable contact. In the circuit breaker comprising a case and a cover for housing the movable contact, the movable contact is attached to the cover, and the movable contact is routed from the left and right sides of the movable contact without sandwiching at least a part of the tip of the movable contact. A pair of shielding plates sandwiched behind the distal end surface of the child, and an end of the shielding plate on the distal end side of the movable contact on the side perpendicular to the track surface of the movable contact, facing the arc An arc facing plate having a surface, and the shielding plate and the arc facing plate are disposed apart from the fixed contact.

  According to the circuit breaker according to the present invention, it becomes possible to prevent re-ignition by maintaining a sufficient insulation interval, and the current limiting performance can be improved and the reliability of the interruption can be improved. A circuit breaker having a high breaking performance up to can be obtained.

It is a sectional side view which shows the principal part structure in the open circuit state in the circuit breaker which concerns on Embodiment 1 of this invention. It is a perspective view which shows the principal part structure except the case and cover which were shown in FIG. 1 in the circuit breaker concerning Embodiment 1 of this invention. It is a perspective view which shows the principal part structure except the case and cover in the open circuit state in the circuit breaker concerning Embodiment 2 of this invention. It is a sectional side view which shows the principal part structure in the open-circuit state in the circuit breaker concerning Embodiment 3 of this invention. It is a sectional side view which shows the principal part structure in the open state which concerns on the conventional circuit breaker.

Embodiment 1 FIG.
Hereinafter, a circuit breaker according to Embodiment 1 of the present invention will be described with reference to FIG. 1 and FIG. FIG. 1 is a side cross-sectional view showing the main configuration of the circuit breaker according to Embodiment 1 of the present invention in an open state. 2 is a perspective view showing a configuration of a main part excluding the case and the cover shown in FIG. 1 in the circuit breaker according to Embodiment 1 of the present invention.

  In each figure, the peripheral portion of the arc-extinguishing chamber 20 of the circuit breaker includes a relay unit that detects an abnormal current (not shown) and outputs a contact opening command, and a drive mechanism unit that is a transmission destination of the opening commander. Are housed in a housing together with a case 1 and a cover 2 made of an insulator constituting the housing, and are separated into three phases in parallel.

  In the arc extinguishing chamber 20 of each phase, a fixed contact 8 to which the fixed contact 9 is fixed, and a movable contact 6 to which the movable contact 7 is fixed at one end side are disposed. The movable contact 6 linked to a drive mechanism (not shown) is rotated around the rotation shaft 6a to be opened and closed.

  Further, above the fixed contact 8, a plurality of magnetic material layers are stacked at predetermined intervals so as to capture and cool an arc generated between the fixed contact 3 and the movable contact 5 at the time of opening. The arc extinguishing grid plate 10 is arranged so as to face the track path of the movable contact 6, that is, the tip of the movable contact 6.

  Further, an exhaust port (not shown) is provided on the left side in FIG. 1 in order to discharge the hot gas accompanying the arc generation to the outside of the circuit breaker. Therefore, when the arc is generated, the internal pressure of the arc extinguishing chamber 20 is increased, so that a strong pressure gradient is generated between the space between the fixed contact 9 and the movable contact 7 and the exhaust port, and the arc is pushed into the arc extinguishing grid plate 10. A gas flow is generated.

  In addition, the configuration of the arc extinguishing grid plate 10 and other parts (not shown) (the relay unit, the drive mechanism unit, and the omitted part of the casing) are the same as, for example, the conventional technique of Patent Document 1 described above. Or it has a corresponding configuration.

  The first embodiment has a shape that does not surround at least a part of the distal end portion of the movable contact 6 as compared with the conventional structure described above, and the distance from the movable contact 6 is small within a design allowable range. The shield plate 3 is attached to the cover 2 and the arc-facing plate 4 is disposed at the end of the shield plate 3 on the distal end side of the movable contact 6 on the side perpendicular to the track surface of the movable contact 6. It is attached. The shielding plate 3 is disposed so as to be sandwiched behind the distal end surface of the movable contact 6 without sandwiching at least a part of the distal end of the movable contact 6 from the left and right sides of the path of the movable contact 6.

  With this configuration, when the current is interrupted, a strong pressure gradient is locally generated between the movable contact 7 and the tip of the movable contact 6, and the arc spot is transferred from the movable contact 7 to the tip of the movable contact 6. Can be guided to the department.

  Since the arc in which the arc spot has moved to the tip of the movable contact 6 exists in the vicinity of the arc extinguishing grid plate 10, it becomes easy to push the arc into the arc extinguishing grid plate 10.

  Moreover, even if the arc moved to the tip of the movable contact 6 tries to return to the movable contact 7 side due to some cause, for example, diffusion of hot gas, reflection of hot gas from the inner wall of the case 1 constituting the housing, Since the arc facing plate 4 is disposed on the movable contact 7 side, pyrolysis gas is injected in a direction to stop the movement to return from the arc facing plate 4 to the movable contact 7 side, and the arc is further caused by this pyrolysis gas. After cooling, the arc is pushed into the arc extinguishing grid plate 10 by the force of gas injection, and cooling is further promoted.

  Further, since the arc having the arc spot at the tip of the movable contact 6 comes close to the arc extinguishing grid plate 10, the attractive force of the arc extinguishing grid plate 10 formed of a magnetic material acts effectively. Thus, the arc spontaneously enters between the plurality of arc extinguishing grid plates 10.

  When the small current is interrupted, the attraction force is particularly strong when the arc is located at a position close to the arc extinguishing grid plate 10. Therefore, even when the small current is interrupted, the arc is extinguished. 10 can be sufficiently cooled.

  Further, since the arc is thick and spreads at the time of interruption at a large current at which the arc is likely to adhere, the arc whose arc spot has moved to the tip of the movable contact 6 always comes into contact with the arc facing plate 4. Therefore, a strong jet gas from the arc facing surface is always sprayed onto the arc, and the arc is pushed into the arc extinguishing grid plate 10 by the jet gas without adhering. As a result, high current limiting performance can be ensured even when a large current is interrupted.

  Further, for example, as shown in the figure, the shield plate 3 and the arc facing plate 4 are arranged apart from those in contact with the fixed contact 8 such as the fixed contact 8 or the slit arc extinguishing plate. This makes it possible to secure a sufficient insulation distance and prevent re-ignition even when creeping resistance deteriorates due to metal melt or flaws, etc. Current limiting can be performed.

  Furthermore, the arc spot is relatively far from the movable contact 7 that is relatively close to the shielding plate 3 by the above-described configuration in which the shielding plate 3 and the arc facing plate 4 that do not sandwich a tip portion of the movable contact 6 are arranged. Since it moves to the front-end | tip part of the movable contact 6, and is maintained in the position, the contact wear of the movable contact 7 can be suppressed and the cause of the reliability fall by a conduction defect etc. can also be prevented.

  Further, as in the structure of the shielding plate 3 in FIG. 1, the movable contact 7 due to the slit effect is obtained by making the pair of shielding plates 3 not sandwich part of the movable contact 7 and the tip of the movable contact 6. It is also possible to prevent excessive compression of the arc in the vicinity of. Therefore, contact wear of the movable contact 7 caused by the excessively compressed arc until the arc moves to the tip of the movable contact 6 can be suppressed.

  Further, as shown in FIG. 2, an insulating member 5 may be disposed on the arc facing surface of the arc facing plate 4. Depending on whether the focus is on the effectiveness of the slit effect depending on the amount of injection of pyrolysis gas, heat resistance or impact resistance, in the case of one molded material such as shield plate 3 or slit arc extinguishing plate Although the material selection is restricted, the room for material selection is expanded by making the arc facing plate 4 and the insulating member 5 different materials. For example, a slit effect and heat resistance can be obtained by disposing the insulating member 5 formed of a material that easily generates pyrolysis gas on the base portion 4a of the arc facing plate 4 made of a high-strength material having heat resistance and impact resistance. In addition, the arc-facing plate 4 that achieves both impact resistance can be configured.

  Further, the shielding plate 3 or the arc facing plate 4 may be formed integrally with the cover 2. By forming the shielding plate 3 or the arc facing plate 4 integrally with the cover 2, the number of parts can be reduced and the cost can be reduced. Furthermore, since it is configured integrally with the cover 2, there is no fear of failure due to dropping off.

  Further, as shown in the figure, the end face on the fixed contact 8 side of the shielding plate 3 extends below the end face A on the fixed contact 8 side of the movable contact 6 in the open state, that is, extends to the fixed contact 8 side. ing. By configuring in this way, it is possible to prevent an arc from spreading on the end surface A or re-igniting between the end surface A and the stationary contact 8.

  As described above, in the first embodiment, the shielding plate 3 and the arc facing plate 4 are disposed apart from the fixed contact 8 or the slit arc extinguishing plate that is in contact with or close to the fixed contact 8. As a result, re-ignition can be prevented while maintaining a sufficient insulation interval, and the current limiting performance is improved and the reliability of interruption is improved.

  Further, the end of the pair of shielding plates 3 on the front end side of the movable contact 6 that is sandwiched behind the front end surface of the movable contact 6 without sandwiching at least a part of the front end of the movable contact 6. By disposing the arc facing plate 4 in this manner, a strong pressure gradient can be locally generated between the movable contact 7 and the tip of the movable contact 6. Accordingly, the arc can be guided to the tip of the movable contact 6 by riding on the gas flow generated from the strong pressure gradient. As a result, since the arc starting point moves from the movable contact 7 to the tip of the movable contact 6, the arc is generated in the vicinity of the arc extinguishing grid plate 10, and the arc is applied to the arc extinguishing grid plate 10. Pushing becomes easy.

  Further, the arc generated in the vicinity of the tip of the movable contact 6 receives the pyrolysis gas sprayed from the arc facing plate 4 even if it returns to the movable contact 7 side for some reason, and is cooled and forced. It is pushed into the arc extinguishing grid plate 10. Therefore, the cooling of the arc is further promoted, and a high interruption performance can be expected even at a small current or a large current of several tens of KA class.

  As described above, it is possible to realize a circuit breaker having high breaking performance from a small current to a large current without causing re-ignition.

Embodiment 2. FIG.
Next, a circuit breaker according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is a perspective view showing a main part configuration excluding a case and a cover in an open state in a circuit breaker according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the part which is the same as that of Embodiment 1 mentioned above, or an equivalent part.

  In FIG. 3, the arc facing plate 4 provided along with the shielding plate 3 is arranged so that the tip end portion 4 b protrudes toward the arc extinguishing grid plate 10 on the vertical direction side with respect to the track surface of the movable contact 6. ing. In other words, the movable contact 6 and the movable contact 7 are arranged in a tapered shape so as to extend from the side surfaces to the tip of the movable contact 6.

  Note that, similarly to the first embodiment described above, the shielding plate 3 has a shape sandwiched behind the distal end surface of the movable contact without sandwiching at least a part of the distal end of the movable contact 6. . In the second embodiment, even when the movable contact 6 is not held at the maximum opening position when the current is interrupted, the arc is applied to the tip of the movable contact 6 within the range where the shielding plate 3 or the arc facing plate 4 is disposed. Can be guided to the department.

  Further, even when the movable contact 6 is not held in the open position, the movable contact 6 is sandwiched so that the distal end of the movable contact 6 can be seen without sandwiching at least a part of the distal end of the movable contact 6 and the movable contact 7. Thus, the contact shape of the movable contact 7 can be prevented.

  Further, similarly to the above-described first embodiment, an insulating member 5 may be disposed on the arc-facing surface of the arc-facing plate 4, and the same effects as those of the above-described first embodiment are achieved.

  Further, the shielding plate 3 or the arc facing plate 4 may be formed integrally with the cover 2, and the same effect as that of the first embodiment described above can be obtained.

  Further, the end face on the fixed contact 8 side of the shielding plate 3 extends downward from the end face A on the fixed contact 8 side of the movable contact 6 and has the same effect as that of the first embodiment described above.

Embodiment 3 FIG.
Next, a circuit breaker according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 4 is a side cross-sectional view showing the main configuration of the circuit breaker according to Embodiment 3 of the present invention in the open state.

  In Embodiments 1 and 2 described above, the movable contactor 6 in the open state extends to the lower portion near the end surface A on the fixed contact 8 side. However, the insulation distance between the movable contact 6 and the fixed contact 8 is small. If the circuit voltage can be sufficiently secured, the end surface B may be further extended to the vicinity of the fixed contact 9, that is, to the same lower position as the arc extinguishing grid plate 10.

  As shown in FIG. 4, the end surface B on the stationary contact 8 side of the shielding plate 3 is extended to the same lower position as that of the lowermost arc extinguishing grid plate 10, so that an arc is generated in almost the entire arc column. Since the arc extinguishing grid plate 10 can be pushed out in a certain direction by the gas flow generated from the space sandwiched between the shielding plates 3, the current interruption performance is further improved.

  In addition, even before the movable contact 6 reaches the open position, an arc is generated at the distal end of the movable contact 6 by a gas flow caused by a strong pressure gradient generated between the movable contact 7 and the distal end of the movable contact 6. Can be extruded.

  The present invention makes it possible to prevent re-ignition by maintaining a sufficient insulation interval, improve the current limiting performance and improve the reliability of the interruption, and has a high interruption performance from a small current to a large current. It is suitable for realizing a circuit breaker.

DESCRIPTION OF SYMBOLS 1 Case 2 Cover 3 Shielding plate 4 Arc opposing plate 5 Insulating member 6 Movable contact 7 Movable contact 8 Fixed contact 9 Fixed contact

Claims (6)

  A case and a cover for accommodating a movable contact provided with a movable contact, a fixed contact provided with a fixed contact, and an arc extinguishing grid plate provided at a position opposed to a track path of the movable contact The circuit breaker is attached to the cover, and the track path of the movable contact is sandwiched from the left and right sides from the left and right sides of the tip of the movable contact behind the tip of the movable contact without sandwiching at least a part thereof. A pair of shield plates, and an arc-facing plate having an arc-facing surface disposed at the end of the shield plate on the distal end side of the movable contact on the side perpendicular to the track surface of the movable contact The circuit breaker is characterized in that the shielding plate and the arc facing plate are spaced apart from the stationary contact.   2. The circuit breaker according to claim 1, wherein the shielding plate is disposed without sandwiching at least a part of the movable contact.   The circuit breaker according to claim 1, wherein an insulating member is disposed on the arc facing plate.   The circuit breaker according to any one of claims 1 to 3, wherein the shielding plate or the arc facing plate is formed integrally with the cover.   The end face on the fixed contact side of the shielding plate extends to the fixed contact side from the end face on the fixed contact side of the movable contact in an open state. Item 5. The circuit breaker according to any one of items 4 to 4.   The arc facing plate is arranged on the side perpendicular to the track surface of the movable contact so that its tip protrudes from the arc extinguishing grid plate. The circuit breaker according to claim 1.

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