JP2006073200A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shut off a moving part such as an opening and closing mechanism from a molten object of a metal material and an insulating material caused by arc heat. <P>SOLUTION: The mold case 14 of a circuit breaker is constructed by splitting it into the case main part 35, a middle cover 36 installed at the upper side of the case main part 35, and a top cover 37 covering the upper side of this middle cover 36, and a contactor part 4 consisting of a fixed contactor 2 and a movable contactor 3 and an arc extinguishing device 34 are housed in the case main part 35, and the opening and closing mechanism 15 and a tripping mechanism 16 are housed in the middle cover 36. A toggle link 24 of the opening and closing mechanism 15 extracted through a through hole 39 provided at a partition wall 38 at the bottom of the middle case 36 is coupled to a holder 11 holding the movable contactor 3, and the through hole 39 is closed by a shutter 41 interlocked with the opening and closing mechanism 15. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a circuit breaker such as a circuit breaker for wiring and an earth leakage breaker used in a low piezoelectric path.

  As this type of circuit breaker, a fixed case and a movable contact are formed in a mold case composed of a case body and a cover mounted on the upper surface of the case, and the movable contact is rotated through an insulator holder. A contact portion that is movably supported, an arc extinguishing device that extinguishes an arc generated at the contact portion, an opening / closing mechanism that opens and closes the movable contact, and a tripping mechanism that trips the lock of the opening / closing mechanism A circuit breaker comprising a mechanism and an overcurrent tripping device that detects an overcurrent and activates the tripping mechanism, wherein the toddler link of the switching mechanism that is reversed when the switching spring is over the dead center and the holder are connected. Generally known, for example, it is described in Patent Document 1.

  In such a circuit breaker, when a large current such as a short circuit current is interrupted, the molten metal material or insulating material is scattered by the arc heat, and this melt adheres to the opening / closing mechanism or tripping mechanism. Function may be impaired. Therefore, in the circuit breaker described in Patent Document 2, an insulating partition is provided vertically between the contact portion and the opening / closing mechanism, and the movable contact is opened and closed along the notch provided in the insulating partition. This prevents the melt from entering the open / close mechanism. However, even if an insulating partition is provided between the contact portion and the opening / closing mechanism in the same case main body as the contact portion, there is a problem that the melt enters from a notch for penetrating the movable contact.

On the other hand, in Patent Document 3 (FIGS. 1 and 2) and Patent Document 4 (FIGS. 1 and 2), a contact portion and an arc-extinguishing plate composed of a fixed contact and a movable contact are individually airtight. There is described a circuit breaker that is housed in a housing and installed in a mold case to increase the internal pressure of an arc generating space to improve arc extinguishing performance. If the case has a double structure as described above, it is considered effective for preventing the molten material from being scattered by the arc heat.
Japanese Patent Laid-Open No. 5-211024 Japanese Patent Laid-Open No. 9-129074 JP-A-9-330642 WO01 / 041168

  However, as described in Patent Document 3 and Patent Document 4, the structure in which the contact portions of each pole are housed in independent housings increases the size of the contact portions and thus the size of the circuit breaker. In addition, an increase in the number of parts (body) causes a cost increase. In addition, it is inevitable that the melt due to the arc heat is ejected to some extent from the cutout of the casing for connecting the movable contactor to the opening / closing mechanism.

  Accordingly, an object of the present invention is to reliably shield movable parts such as an opening / closing mechanism from a melt scattered by arc heat without causing an increase in size of a circuit breaker.

  In order to solve the above-mentioned problems, the present invention comprises a stationary contact and a movable contact, and the movable contact is supported by a contact portion rotatably supported via an insulator holder, and the contact. An arc extinguishing device that extinguishes an arc generated in a section, an opening / closing mechanism that opens and closes the movable contact, a tripping mechanism that trips a lock of the opening / closing mechanism, and an tripping mechanism that detects an overcurrent An overcurrent tripping device for operating the circuit breaker provided in the mold case, wherein the toggle link of the opening / closing mechanism that is reversed when the dead center of the opening / closing spring is exceeded is connected to the holder. The middle cover having a partition wall that is attached to the upper surface of the case body and shields the case body from the bottom, and a top cover that covers the upper surface of the middle cover; A contact portion and an arc extinguishing device are housed in the case body, the opening / closing mechanism and a tripping mechanism are mounted on the middle cover, and the toggle link is connected to the holder through a through hole provided in the partition; and A shutter that closes the through hole in conjunction with the opening / closing mechanism is provided (Claim 1).

  According to the first aspect of the present invention, the opening / closing mechanism and the tripping mechanism are housed in the middle cover separate from the case main body, so that the opening / closing mechanism and the tripping mechanism are isolated from the contact portion housed in the case, and the arc It can protect from adhesion of the melt by heat. In that case, by closing the through hole of the bottom partition wall of the middle cover with a shutter interlocking with the opening / closing mechanism, it is possible to reliably block the melt that enters from the gap of the through hole.

  2. The shutter according to claim 1, wherein the shutter is formed of a flexible thin plate, one end of the shutter is connected to the latch of the opening / closing mechanism, and the latch is rotated by releasing the lock of the opening / closing mechanism. It is preferable that the shutter is moved along the partition wall of the middle cover by operation, so that a reliable shutter can be configured easily (Claim 2).

  In the invention of claim 2, the shutter may be formed of a mesh plate or a perforated plate (invention 3). As a result, the melt due to the arc heat is captured by the shutter, while the gas component passes through the shutter, and an excessive pressure increase in the shut-off space can be suppressed.

  According to the present invention, by storing the opening / closing mechanism and the trip mechanism in the middle cover separate from the case body, these movable parts are shielded from the contact parts housed in the case body, and the melt of the arc due to the arc heat is prevented. A movable part can be reliably protected from adhesion.

  Hereinafter, embodiments of the invention will be described with reference to FIGS. First, FIG. 1 is a vertical cross-sectional view in a closing state showing a central pole portion of a three-pole circuit breaker. In FIG. 1, current flows from a power source terminal 1 to a contact portion 4 comprising a fixed contact 2 and a movable contact 3, a lead wire 5, a lead plate 6, a heater conductor 8 of an overcurrent trip device 7, and a relay conductor. Flows to the load side terminal 10 via 9. The movable contact 3 is rotatably held by a holder 11 made of an insulator via a shaft 12 and is urged counterclockwise in FIG. 1 by a contact spring (not shown). Further, the holders 11 of the respective poles are integrally connected by an opening / closing shaft 13 and are rotatably supported by the mold case 14 via the opening / closing shaft 13.

  The movable contact 3 is opened / closed by a known opening / closing mechanism 15 (for example, see Patent Document 1), and the opening / closing mechanism 15 is always locked by a tripping mechanism 16. Hereinafter, the configuration will be simply described. The opening / closing mechanism 15 is integrally formed on a frame 17 having side plates on the left and right sides. The handle lever 18 is rotatably supported in the left and right directions in FIG. 1, the operation handle 19 is mounted on the head, and one end is rotated by a pin 20. The latch 21 is movably supported, and includes an upper link 22 and a lower link 23. The upper link 22 is connected to the latch 21, and the lower link 23 is a toggle link 24 connected to the holder 11, and the upper link 22 and the lower link. An open / close spring 26 having a lower end connected to a central pin 25 that connects to the handle 23 and an upper end connected to the handle lever 18 is provided.

  Further, the tripping mechanism 16 latches the latch receiver 27 that latches the right end of the latch 21 in FIG. 1, and the trip crossbar 28 that faces the overcurrent tripping device 7 of each pole. The latch receiver 27 is supported by the frame 17 via a pin 29, and the trip cross bar 28 is rotatably supported by the mold case 14.

  Next, operations of the opening / closing mechanism 15 and the tripping mechanism 16 will be described. In FIG. 1, the holder 11 receives the force of the opening / closing spring 26 via the toggle link 24 and brings the movable contact 3 into contact with the fixed contact 2. When the operating handle 19 is opened in this direction from this state, the toggle link 24 is reversed when the dead center of the opening / closing spring 26 is exceeded, and the movable contact 3 is driven to open clockwise via the holder 11 to open the circuit breaker. Open the pole. When the operation handle 19 is closed in the reverse direction from the open state, the illustrated state is restored.

  On the other hand, in FIG. 1, when the current flowing through the circuit breaker is in an overload state, the bimetal 30 of the overcurrent tripping device 7 is bent leftward by the heat generation of the heater conductor 8 and pushes the trip cross bar 28. Thereby, the trip cross bar 28 rotates counterclockwise, and the engagement with the latch receiver 27 is released. Therefore, the latch receiver 27 rotates clockwise and disengages from the latch 21. As a result, the latch 21 rotates counterclockwise, the dead center of the open / close spring 26 is generated, the toggle link 24 is inverted, and the circuit breaker is opened (trip operation). FIG. 2 shows a state in which the circuit breaker of FIG. 1 has tripped.

  Further, when a large current such as a short circuit current flows through the circuit breaker, the armature 31 of the overcurrent tripping device 7 is instantaneously attracted to the fixed core by the magnetic flux of the current flowing through the heater conductor 8, and the trip cross bar 28 is Push. As a result, the toggle link 24 is reversed and the circuit breaker is opened as in the overload state described above. In this case, an arc is generated between the fixed contact 32 and the movable contact 33, and this arc is drawn into the arc extinguishing device 34 to extinguish the arc. At this time, the metal material or the insulating material is melted by the arc heat. , Scattered around with arc gas. If this melt adheres to movable parts such as the opening / closing mechanism 15 and the tripping mechanism 16, their functions may be impaired. Therefore, as will be described below, means for isolating the movable part from the splash of the melt due to the arc heat is taken.

  That is, as shown in FIG. 3, the mold case 14 includes a case main body 35, a middle cover 36 attached to the upper surface thereof, and a top cover 37 covering the upper surface of the middle cover 36. The top cover 37 includes an auxiliary cover 37a that covers openings (not shown) on both the left and right sides. The contact portion 4, the overcurrent tripping device 7, and the arc extinguishing device 34 are housed in a case body 35, and the opening / closing mechanism 15 and the tripping mechanism 16 that are integrally formed on the frame 17 are mounted on a middle cover 36. Yes.

  In FIG. 3, a partition wall 38 that extends over each pole is formed at the bottom of the middle cover 36, and the opening / closing mechanism 15 is attached to a central pole portion on the partition wall 38. The partition wall 38 is provided with a rectangular through hole 39, and the toggle link 24 is drawn downward through the through hole 39. The middle cover 36 to which the opening / closing mechanism 15 is attached is attached to the case body 35 from above, and the lower link 23 is connected to the holder 11. In that case, as described in Patent Document 1, the connection pin 40 (FIG. 1) is fixed to the lower link 23, and the connection pin 40 is inserted into a groove (not shown) provided on the side surface of the holder 11. If the lower link 23 is connected to the holder 11, assembly is facilitated.

  The holder 11 accommodated in the case main body 35 is fitted and held between the semicircular groove 35 a of the main body case 35 and the semicircular groove 36 a of the middle cover 36. The trip cross bar 28 to be mounted is fitted and held between the semicircular groove 36 b of the middle cover 36 and the semicircular groove 37 b of the top cover 37.

  In the toggle link 24, the lower link 23 passes through the through hole 39 of the partition wall 38, but a gap is generated around the lower link 23 in the through hole 39. In order to close this gap, a shutter 41 shown in FIG. 1 is provided. FIG. 4 is a plan view of the through-hole portion in FIG. 1, FIG. 4 (A) is a circuit breaker being put in, and FIG. 4 (B) is a trip state. The lower link 23 includes a pair of left and right arms 23a and 23a, and these arms 23a and 23a are connected to each other by a connecting plate 23b extending between the left and right arms 23a and 23a on a part of the rear side (right side in FIG. 1). . The connecting plate 23b of the lower link 23 is in a position overlapping the through hole 39 in the closing state of FIG.

  On the other hand, the shutter 41 is a strip-shaped plate made of a flexible thin plate such as metal or resin, and one end of the shutter 41 is rotatably connected to the latch 21 via a pin, and the free end is a middle cover 36. It extends on the through hole 39 along the partition wall 38. The shutter 41 is loosely inserted between the two guide pins 42 and 43 fixed to the frame 17 and the support pin 20 of the latch 21 and the partition wall 38 and is bent into a U shape along the partition wall 38. In the state shown in FIG. 1, the tip of the shutter 41 lies between the arms 23a and 23a of the lower link 23 and abuts against the connecting plate 23b.

  Next, the operation of the shutter 41 during the trip operation of the circuit breaker will be described with reference to FIG. As already described, the latch 21 and the latch receiver 27 are disengaged during the trip operation, and the latch 21 rotates counterclockwise. At the same time, the shutter 41 is pushed into the through hole 39 side, and the lower link 23 rises, and the connecting plate 23 b comes out of the through hole 39 upward. Therefore, the tip of the shutter 41 advances under the connecting plate 23b, and completely covers the through hole 39 as shown in FIG. Thereby, during the trip operation, a gap generated around the lower link 23 in the through hole 39 is closed by the shutter 41.

  According to the illustrated embodiment, movable parts such as the opening / closing mechanism 15 and the tripping mechanism 16 are accommodated in a middle cover 36 that is separate from the case main body 35, and toggle links are provided through the through holes 39 provided in the partition wall 38 at the bottom of the middle cover. By connecting 24 to the holder 11, these movable parts are isolated from the contact part 4, and adhesion of the melt due to arc heat is suppressed. The shutter 41 interlocked with the opening / closing mechanism 15 closes the gap around the toggle link 24 that passes through the through hole 39, and reliably prevents the intrusion of the melt from the through hole 39.

  FIG. 5 is a plan view of a through hole portion showing a different embodiment of the shutter 41. In this embodiment, the front end portion of the shutter 41 is formed as a perforated plate having a large number of small holes 44. According to such a shutter 41, the melt due to the arc heat is captured by the shutter 41, while the arc gas escapes into the middle cover through the small hole 44. As a result, the increase in internal pressure due to the arc gas is mitigated, and the risk of damage to the case body 35 due to the increase in internal pressure is reduced. The shutter 41 that allows only the arc gas to pass and captures the melt can also be configured using a mesh plate made of a wire mesh or the like.

  In the middle cover 36 of FIG. 3, it is preferable to store the interior accessories in the lateral space of the opening / closing mechanism 15, so that the interior accessories can also be protected from adhesion of the melt. The internal accessories include auxiliary contacts that detect the open / close status of the circuit breaker, alarm contacts that detect the trip status of the circuit breaker, and circuit breakers when the voltage of the circuit where the circuit breaker is inserted falls below the specified level. An undervoltage trip device for tripping a circuit, a voltage trip device for remotely operating a circuit breaker, and the like (see Japanese Patent Application Laid-Open No. 6-236726). The top cover 37 is provided with an opening corresponding to the accessory storage space, and the auxiliary cover 37a already described is attached to the opening.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a circuit breaker in a closed state showing an embodiment of the present invention. It is a longitudinal cross-sectional view of the trip state of the circuit breaker of FIG. It is a decomposition | disassembly longitudinal cross-sectional view of the mold case in FIG. 1A is a plan view of the main part of FIG. 1, and FIG. It is a principal part top view of the through-hole part which shows embodiment from which a shutter differs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Fixed contact 3 Mobile contact 4 Contact part 7 Overcurrent tripping device 11 Holder 14 Mold case 15 Opening / closing mechanism 16 Tripping mechanism 21 Latch 24 Toggle link 26 Opening / closing spring 34 Arc extinguishing device 35 Case main body 36 Middle cover 37 Top Cover 38 Bulkhead 39 Through hole 41 Shutter 44 Small hole

Claims (3)

A movable contact comprising a fixed contact and a movable contact, the movable contact being rotatably supported via an insulator holder, and an arc extinguishing device for extinguishing an arc generated at the contact. An open / close mechanism that opens and closes the movable contact, a trip mechanism that trips a lock of the open / close mechanism, and an overcurrent trip device that detects an overcurrent and activates the trip mechanism. In the circuit breaker in which the toggle link of the opening / closing mechanism that is reversed by exceeding the dead point of the opening / closing spring is connected to the holder,
The mold case is divided into a case main body, a middle cover that is attached to the upper surface of the case main body and has a partition wall that shields between the case main body and a top cover that covers the upper surface of the middle cover. The contact portion and the arc extinguishing device are housed in the case body, the opening / closing mechanism and the tripping mechanism are mounted on the middle cover, and the toggle link is attached to the holder through a through hole provided in the partition wall. The circuit breaker according to claim 1, further comprising a shutter that connects and closes the through hole in conjunction with the opening / closing mechanism.   The shutter is formed of a flexible thin plate, and one end of the shutter is connected to the latch of the opening / closing mechanism, and the shutter is moved by rotating the latch by releasing the lock of the opening / closing mechanism. 2. The circuit breaker according to claim 1, wherein the circuit breaker is moved along the partition wall of the middle cover. 3. The circuit breaker according to claim 2, wherein the shutter is formed of a mesh plate or a perforated plate.

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