JP4466237B2 - Circuit breaker - Google Patents

Description

  The present invention relates to a circuit breaker such as a circuit breaker for wiring and an earth leakage breaker used for a low piezoelectric path, and more particularly to a means for promoting an increase in arc voltage when a current is interrupted.

  FIG. 10 shows a general configuration of the breaker of the circuit breaker. In FIG. 10, a fixed contact 101 fixed to a case (not shown) has a fixed contact 102 at one end, and a power supply side terminal 103 is integrally formed at the other end. In the vicinity of the fixed contact 102, an arc runner 104 that rises obliquely toward the terminal side is provided. The movable contact 105 has a movable contact 106 that contacts the fixed contact 102 at one end, and is rotatably connected via a shaft 107 to a movable contact holder (not shown) whose other end is rotatably supported by the case. Has been.

The arc extinguishing chamber 108 has a plurality of U-shaped magnetic plates 109 that are stacked and supported on a support of an insulator (not shown) via a gap, and the magnetic plate 109 surrounds the movement locus of the movable contact 106. Has been placed. When the current is interrupted, an arc 110 is generated between the fixed contact 102 and the movable contact 106. The arc 110 is drawn into the magnetic plate 109, divided and cooled, and the arc voltage is increased to extinguish the arc. Such a circuit breaker is described in Patent Document 1, for example.
JP-A-60-72131

  In the circuit breaker described above, in order to increase the arc voltage and improve the breaking performance, it is necessary to increase the number of magnetic plates in the arc extinguishing chamber as much as possible. On the other hand, in order to use all of the magnetic plates effectively for arc division, the opening distance of the movable contact according to the number of magnetic plates is required. As shown in FIG. It is necessary to make the tip of the contact higher than the uppermost magnetic plate. Therefore, when the number of magnetic plates increases, the opening distance of the movable contact also increases, and it becomes necessary to change the switching mechanism and enlarge the external dimensions of the circuit breaker. If the number of magnetic plates is increased without changing the opening distance of the movable contact, the tip of the movable contact becomes lower than the uppermost magnetic plate, and the uppermost magnetic plate cannot be used effectively.

  In such a case, as described in Patent Document 1, there is a method of providing an arc transition portion on the uppermost magnetic plate. However, in the case of a relatively small circuit breaker having a breaking current of several kA level, When the current increases, the arc is less likely to be bent as shown in FIG. 11, which makes it difficult to transfer to the uppermost magnetic plate.

  An object of the present invention is to make it possible to effectively use the uppermost magnetic plate while suppressing the opening distance of the movable contact even when the breaking performance is improved by increasing the number of magnetic plates in the arc extinguishing chamber. There is.

In order to solve the above-described problems, the present invention has a fixed contact that is fixed to a case and has a fixed contact at one end, a movable contact that contacts the fixed contact at one end, and the other end is rotatable to the case. A movable contact connected to the movable contact holder supported by the plurality of U-shaped magnetic plates stacked and supported via a gap, and arranged so as to surround the movement locus of the movable contact. A circuit breaker that draws an arc generated between the fixed contact and the movable contact into the magnetic plate of the arc extinguishing chamber and extinguishes the arc. And an insulating member having a pair of side walls covering the movement locus of the movable contact from the left and right sides inside the legs of the magnetic plate, and a position higher than the tip of the movable contact at the opening position. The tip of the movable contact in the open position Are adapted to protrude from a side wall upper surface of the insulating member, the said upper corner portion of the magnetic plate side of the side wall so Desa extends to the vicinity of the magnetic plate of the top-level, further, the left and right side walls of the insulating member from its upper surface A partition wall that shields the vicinity of the tip of the projecting movable contact from both legs of the magnetic plate is formed, and the distance between the partition walls is wider than the distance between the side walls .

  According to the first aspect of the present invention, a pair of side walls of the insulating member is disposed inside both legs of the magnetic plate of the arc extinguishing chamber so as to cover the movement locus of the movable contact from both the left and right sides, and becomes larger than the interval between the left and right side walls. The arc is pushed out into a large space outside the side wall. In that case, by projecting the tip of the movable contact at the open position from the upper surface of the side wall of the insulating member, the arcing point of the arc on the movable contact side can be quickly transferred to the tip of the movable contact, and insulation By extending the upper corner of the side wall of the member to the vicinity of the uppermost magnetic plate, the arc pushed out from the upper corner enters the uppermost magnetic plate.

  As a result, even when the number of magnetic plates is increased and this magnetic plate is stacked up to a position higher than the tip of the movable contact at the opening position, the uppermost magnetic plate can be used effectively and opened. It is possible to suppress the opening distance so that the tip position of the movable contactor does not exceed the height of the uppermost magnetic plate.

  The electromagnetic force from the magnetic plate acts on the arc in the vicinity of the movable contact, but the point from the tip of the movable contact protruding from the upper surface of the side wall of the insulating member at the open position to the leg of the magnetic plate in the vicinity. When arcing, the electromagnetic force does not work on the arc, and the current flows through the legs of the magnetic plate, so the arc length is shortened. According to the first aspect of the present invention, by forming the partition wall that shields the vicinity of the tip of the movable contact protruding from the upper surface of the side wall of the insulating member from both legs of the magnetic plate, arcing at the legs of the magnetic plate is prevented. can do. Moreover, in that case, by making the interval between the partition walls wider than the interval between the side walls, the arc firing point can be maintained at the tip of the movable contact without being pushed out between the partition walls.

Furthermore, in this invention, it is preferable to form an inclined surface at the upper corner of the side wall so that the interval between the side walls gradually increases toward the tip.
Thereby, the extension of the arc toward the uppermost magnetic plate can be promoted. It is more effective if the inclined surface is formed on the entire side wall.

  According to the present invention, even when the number of magnetic plates is increased, the uppermost magnetic plate can be used effectively without increasing the opening distance of the movable contact, and the switching mechanism can be changed or the circuit breaker outer shape can be changed. The arc voltage can be increased without enlarging, and the interruption performance can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 is a longitudinal sectional view of an essential part of a central pole portion of a three-pole circuit breaker. In FIG. 1, an insulating container composed of a case 1 and a cover 2 is provided with a blocking portion composed of a fixed contact 3 fixed to the case 1 and a movable contact 5 that is opened and closed by an opening / closing mechanism 4. Yes. Although the figure shows the blocking part of the central pole portion, the inside of the insulating container is partitioned into three-phase spaces by phase spacing walls, and each phase blocking part is accommodated in each space. The fixed contact 3 has a fixed contact 6 at one end, and a power supply side terminal 7 is integrally formed at the other end. An arc runner 8 that rises obliquely toward the power supply side (left side in the figure) is attached to the fixed contact 3 in the vicinity of the fixed contact 6. The arc runner 8 may be integrally cut and formed from the fixed contact 3.

  The movable contact 5 has a movable contact 9 that contacts the fixed contact 6 at one end, and can be rotated by a shaft 11 on a movable contact holder 10 made of an insulator that is rotatably supported by the case 1 at the other end. The contact spring 12 is connected to the movable contact holder 10 and is inserted between the movable contact holder 10 and biased toward the fixed contact 3. An arc extinguishing chamber 13 is composed of an insulating support 14 and a plurality of magnetic plates 15 stacked and supported on the support 14 with an appropriate gap. The magnetic plate 15 passes through the movable contact 5. A notch is provided to form a U shape. The arc extinguishing chamber 13 is disposed so as to surround the movement locus of the movable contact 9 by the magnetic plate 15.

  The opening / closing mechanism 4 is connected to the movable contact holder 10, and the movable contact 5 is driven to open / close by the opening / closing mechanism 4 via the movable contact holder 10. An arc gas discharge port 16 is provided in front of the blocking portion, and the arc gas discharge port 16 is closed by an insulating protective plate 17 that prevents foreign matter from entering.

  2 and 3 show the blocking portion, FIG. 2 is a plan view, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 and 3, the support 14 of the arc-extinguishing chamber 13 is formed into a U-shape by bending a fiber plate punched into a required shape, and a rectangular ventilation window that allows arc gas to pass through the center of the front wall. 18 is opened. The magnetic plate 15 is stamped and formed in a U shape from an iron plate, and a notch 19 is provided in a portion through which the movable contact 5 passes. The magnetic plate 15 is crimped to the support 14 via the left and right projecting pieces, but in the illustrated case, a larger number of magnetic plates 15 are stacked than in the prior art (for example, the conventional example of FIG. 11). The position of the uppermost magnetic plate 15 is higher than the tip of the movable contact 5 at the opening position indicated by a broken line in FIG. In FIG. 1, the arc extinguishing chamber 13 is placed on the bottom surface of the case 1 formed in the same shape as the lower end surface of the support 14, and the upper end surface is pressed and fixed by the cover 2.

  Here, an insulating member 20 is installed inside the arc extinguishing chamber 13. FIG. 4 is a perspective view showing the insulating member 20. The insulating member 20 is formed from a resin such as polyamide, polyacetal, or polyester, and has a pair of left and right side walls 21. The left and right side walls 21 are connected to each other at the lower portion by a connecting portion 22 (FIG. 3). Further, on the back side of the side wall 21 (right side in FIG. 2), a back wall 23 is integrally provided so as to project to the left and right sides, and a shoulder 24 is formed on the shoulder. On the other hand, on the lower surface of the side wall 21, as shown in FIG. 4, inclined surfaces 25 and 26 are formed in steps, and a protruding portion 27 is further formed.

  As shown in FIGS. 2 and 3, the insulating member 20 is combined with the arc extinguishing chamber 13, the side wall 21 abuts on a leg portion that sandwiches the notch 19 of the magnetic plate 15, and the back wall 23 contacts the back surface of the support 14. In the state where the arc extinguishing chamber 13 is mounted on the case 1 (FIG. 1), the insulating member 20 is positioned by fitting the protruding portion 27 with a receiving portion (not shown) on the bottom surface of the case 1. 24 is pressed and fixed by a step 14 a (FIG. 3) on the back side of the support 14. In this state, the insulating member 20 is placed on the stationary contact 3 as described later.

  In FIG. 3, the end of the fixed contact 3 to which the fixed contact 6 is attached is bent in a U-shape to form an inclined surface, and an arc runner 8 is attached to the inclined surface. As shown in FIG. 4, the arc runner 8 protrudes from the left and right sides of the mounting end, and two right and left caulking pins integrally formed with the fixed contact 3 are inserted into the holes of the protruding end, and the tip thereof is caulked. And is coupled to the stationary contact 3. As shown in FIG. 3, the insulating member 20 is placed on the upper surface of the stationary contact 3, the inclined surface 25 of the side wall 21 contacts the left and right protruding portions of the arc runner 8, and the inclined surface 26 (FIG. 4) of the side wall 21 is fixed contact. 6 abuts against the inclined surface of the stationary contact 3 on both sides.

  In the state in which the arc extinguishing chamber 13 and the insulating member 20 are assembled in the case 1 as described above, the side wall 21 of the insulating member 20 moves inside the legs of the magnetic plate 15 as shown in FIG. 3) Cover the left and right sides. Here, in FIG. 3, the tip of the movable contact 5 at the opening position indicated by the broken line protrudes from the upper surface of the side wall 21 of the insulating member 20 and the back side of the magnetic plate 15 on the side wall 21 (left side in FIG. 3). The upper corner portion 21 a extends to the vicinity of the uppermost magnetic plate 15.

  In the illustrated circuit breaker, when a large current such as a short circuit current flows, an electromagnetic repulsion force due to a concentrated current acts between the fixed contact 7 and the movable contact 9, and the movable contact 5 opens against the contact spring 12. To do. Simultaneously with the opening of the movable contact 5, an arc 29 is generated between the fixed and movable contacts 6 and 9 as shown in FIG. 5. The generated arc 29 is magnetized by the electromagnetic force generated by the magnetic plate 15 and the gas flow from the side wall 21 disposed on both sides of the contacts 6 and 9 to the arc gas discharge port 16 (FIG. 1) of pyrolysis gas generated by the arc heat. It is driven to the back side of the plate 15. The driven arc 29 enters between several sheets on the lower side of the laminated magnetic plates 15 at the same time that the firing point on the stationary contact 3 side is transferred from the stationary contact 6 to the arc runner 8. The movable contact 5 opened by the electromagnetic repulsive force is held at the open position by the movable contact holder 10 that is rotationally driven by the operation of the opening / closing mechanism 4 based on the trip signal from the overcurrent trip device. .

  On the other hand, the arcing point of the movable contact 5 similarly changes from the movable contact 9 to the tip of the movable contact 5, and at the same time, the section of the arc 29 sandwiched between the upper corners 21a of the side wall 21 has an upper corner portion. It is extended and curved toward the upper left of FIG. 5 so as to be pushed into the outer space wider than the interval of 21 a and enters the uppermost magnetic plate 15. In addition, on the back side of the magnetic plate 15, the contour of the side wall 21 has a curved shape when the arc 29 extends and curves with the arc runner 8 from the tip of the movable contact through the uppermost magnetic plate. The arc 29 is also formed on the left side of FIG. 5 so as to be pushed out into a wide space even on the lower side of the upper corner portion 21a. As a result, the entire arc enters between the magnetic plates 15 and is divided and cooled between them, and the arc voltage rises. In that case, the arcing point at the tip of the movable contact 5 is out of the narrow space between the side walls 21, so it is difficult to return to the movable contact 9, the curved shape of the arc 29 is stably maintained, and the movable contact 9 There is little consumption.

FIG. 6 is a perspective view of an insulating member showing Embodiment 1 of the present invention. In FIG. 6, the left and right side walls 21 of the insulating member 20 are integrally formed with partition walls 30 that shield the vicinity of the tip of the movable contact 5 at the opening position protruding from the upper surface from both legs of the magnetic plate 15. Is different from FIG. The partition walls 30 are thinner than the side walls 21, and the distance between the partition walls 30 is wider than the distance between the side walls 21.

  As shown in FIG. 5, when the arc 29 is transferred to the tip of the movable contact 5, when the arc 29 is ignited by the leg portion of the magnetic plate 15 in the vicinity thereof, the arc 29 tries to be drawn into the back of the magnetic plate 15. Besides reducing the electromagnetic force, the current flows through the arm of the magnetic plate 15, so the arc length is shortened and the arc voltage is lowered. In the second embodiment, since the partition wall 30 is formed on the side wall 21 of the insulating member 20, the arc 29 near the tip of the movable contact 5 is shielded from the leg portion of the magnetic plate 15 by the partition wall 30. It stretches and curves toward the uppermost magnetic plate 15 without arcing on the magnetic plate 15.

FIG. 7 is a perspective view of an insulating member showing Embodiment 2 of the present invention. 7 is different from FIG. 5 in that an inclined surface 31 is formed in the upper corner portion 21a of the side wall 21 so that the interval between the side walls 21 gradually increases toward the tip. According to the third embodiment, the arc extension toward the uppermost magnetic plate 15 can be induced more smoothly. It is more effective if the inclined surface of the side wall 21 is formed on the entire surface toward the back of the magnetic plate 15.

FIG. 8 is a perspective view of an insulating member showing Embodiment 3 of the present invention. 8 is different from FIG. 5 in that an insulating connecting portion 32 for connecting the left and right side walls 21 is provided on the side opposite to the movable contact 9 at the tip of the movable contactor 5 at the opening position. Yes. According to the fourth embodiment, since pyrolysis gas is generated from the connecting portion 32 behind the arc that is ignited at the tip of the movable contact 5, the extension of the arc toward the arc gas exhaust port is promoted. The connecting portion 32 is preferably formed integrally with the insulating member 20, but a separate member may be attached.

FIG. 9 is a longitudinal sectional view of a blocking portion showing Embodiment 4 of the present invention. 9 is different from FIG. 5 in that an arc transition plate 33 is formed upright on the upper surface of the uppermost magnetic plate 15. The illustrated arc transition plate 33 is coupled to the magnetic plate 15 as a separate member, but may be integrally cut and bent from the magnetic plate 15. According to the fifth embodiment, by providing the arc transition plate 33 on the uppermost magnetic plate 15, the arc 29 between the tip of the movable contact 5 and the arc transition plate 33 is stabilized. The maintenance of is good.

It is a longitudinal cross-sectional view of the circuit breaker which shows the basic composition of Example 1 of this invention. It is a top view of the interruption | blocking part in FIG. It is sectional drawing which follows the III-III line of FIG. It is a perspective view of the insulating member in FIG. It is a figure which shows the state of the arc at the time of opening of the interruption | blocking part of FIG. It is a perspective view of the insulating member which shows Example 1 of this invention. It is a perspective view of the insulating member which shows Example 2 of this invention. It is a perspective view of the insulating member which shows Example 3 of this invention. It is a longitudinal cross-sectional view of the interruption | blocking part which shows Example 4 of this invention. It is a longitudinal cross-sectional view which shows the interruption | blocking part of the conventional circuit breaker. It is a figure explaining the mode of an arc when the interruption | blocking current of the interruption | blocking part of FIG. 10 is large.

DESCRIPTION OF SYMBOLS 3 Fixed contact 4 Opening / closing mechanism 5 Movable contact 6 Fixed contact 8 Arc contactor 9 Movable contact 13 Arc extinguishing chamber 14 Support 15 Magnetic plate 20 Insulating member 21 Side wall 21a Side corner upper part 28 Moving track 29 Arc 30 Bulkhead 31 Inclined surface 32 Connecting part 33 Arc transition plate

Claims (2)

A fixed contact that is fixed to the case and has a fixed contact at one end, a movable contact that contacts the fixed contact at one end, and the other end connected to a movable contact holder that is rotatably supported by the case A movable contact; and a plurality of U-shaped magnetic plates stacked and supported via a gap, and an arc extinguishing chamber disposed so as to surround the movement locus of the movable contact, and when the current is interrupted In a circuit breaker that draws an arc generated between a fixed contact and a movable contact into a magnetic plate of the arc extinguishing chamber and extinguishes the arc,
While laminating the magnetic plate of the arc extinguishing chamber to a position higher than the tip of the movable contact at the opening position, a pair of side walls covering the movement locus of the movable contact from both the left and right sides inside the legs of the magnetic plate And having the tip of the movable contact at the open position project from the upper surface of the side wall of the insulating member, and the upper corner portion of the side wall to the vicinity of the uppermost magnetic plate Further, partition walls are formed on the left and right side walls of the insulating member to shield the vicinity of the tip of the movable contact protruding from the upper surface from both legs of the magnetic plate, and the distance between the partition walls. The circuit breaker is characterized in that it is wider than the interval between the side walls . A fixed contact that is fixed to the case and has a fixed contact at one end, a movable contact that contacts the fixed contact at one end, and the other end connected to a movable contact holder that is rotatably supported by the case A movable contact; and a plurality of U-shaped magnetic plates stacked and supported via a gap, and an arc extinguishing chamber disposed so as to surround the movement locus of the movable contact, and when the current is interrupted In a circuit breaker that draws an arc generated between a fixed contact and a movable contact into a magnetic plate of the arc extinguishing chamber and extinguishes the arc,
While laminating the magnetic plate of the arc extinguishing chamber to a position higher than the tip of the movable contact at the opening position, a pair of side walls covering the movement locus of the movable contact from both the left and right sides inside the legs of the magnetic plate And having the tip of the movable contact at the open position project from the upper surface of the side wall of the insulating member, and the upper corner portion of the side wall to the vicinity of the uppermost magnetic plate A circuit breaker characterized in that it is extended and an inclined surface is formed at the upper corner of the side wall so that the interval between the side walls gradually increases toward the tip .

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