JP4428076B2 - 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 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 part supported movably, an arc extinguishing device for extinguishing an arc generated in the contact part, an opening / closing mechanism for opening / closing the movable contact, and a tripping mechanism for releasing the lock of the opening / closing mechanism Circuit having a mechanism and an overcurrent tripping device for detecting the overcurrent and operating the tripping mechanism, and the switching mechanism is connected to the holder via a toggle link that reverses when the dead center of the switching spring is exceeded. A circuit breaker is known and is described, for example, 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. May impair its function. Therefore, in the circuit breaker described in Patent Document 2, an insulating partition is provided between the contact portion and the opening / closing mechanism in an arc extinguishing device, and the movable contact is opened / closed along a notch provided in the insulating partition. By operating, the intrusion of the melt into the opening / closing mechanism portion is prevented.
Japanese Patent Laid-Open No. 5-211024 Japanese Patent Laid-Open No. 9-129074

  However, the opening / closing mechanism housed in the same case body as the contact portion is not sufficiently shielded even if a vertical insulating partition as described in Patent Document 2 is provided, and a notch or the like that allows the movable contact to pass through. There was a problem that the melt that entered from the gap still adhered.

  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.

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 for extinguishing an arc generated in the section, an opening / closing mechanism for opening / closing the movable contact, a tripping mechanism for releasing the lock of the opening / closing mechanism, and a tripping mechanism for detecting an overcurrent In the circuit breaker connected to the holder via a toggle link that reverses when the open / close spring exceeds the dead center
The mold case is divided into a case main body, a middle cover attached to the upper surface of the case main body, and a top cover covering the upper surface of the middle cover, and a slit is provided on a part of the bottom of the middle cover. The contact portion and the arc extinguishing device are housed in the case body, and the opening / closing mechanism and a tripping mechanism for releasing the lock of the opening / closing mechanism are housed in the middle cover, and The toggle link is connected to the holder through a provided slit . (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, whereby the opening / closing mechanism and the tripping mechanism are isolated from the contact portion housed in the case main body, Adhesion of melt due to arc heat is suppressed. The opening / closing mechanism and the tripping mechanism are more reliably shielded from the melt by the partition formed at the bottom of the middle cover.

  In the first aspect of the present invention, an interior accessory may be housed in a side of the opening / closing mechanism in the middle cover. In a multi-pole circuit breaker, the switching mechanism is connected to one of the poles, and the other pole has a space in the middle cover, so if you store interior accessories such as auxiliary contacts and alarm switches in this space, Easy to install and hold interior accessories.

  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 can be easily shielded from the contact parts housed in the case body and melted by arc heat. It is possible to reliably prevent malfunction of the movable part due to adhesion of objects.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. First, FIG. 1 is a longitudinal sectional view showing a central pole portion of a three-pole circuit breaker. In the input state of FIG. 1, the current flows from the power supply side terminal 1 to the contact portion 4 including the fixed contact 2 and the movable contact 3, the lead wire 5, the lead plate 6, and the heater conductor 8 of the overcurrent tripping device 7. Then, the current flows to the load side terminal 10 via the relay conductor 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. The holders 11 of each pole are integrally connected to each other, and the movable contact 3 is rotatably supported by the mold case 14 via the holder 11.

  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. The configuration will be briefly described below. The opening / closing mechanism 15 and the tripping mechanism 16 are integrally formed on a frame 17 having side plates on the left and right. The opening / closing mechanism 15 includes a handle lever 18 supported so as to be pivotable to the left and right of FIG. 1, an operation handle 19 mounted on the head thereof, a latch 21 supported pivotally by a pin 20 at the left end of FIG. The upper link 22 is composed of an upper link 22 and a lower link 23. The upper link 22 is connected to the latch 21. The lower link 23 is connected to a toggle link 24 connected to the holder 11, and a central pin 25 connecting the upper link 22 and the lower link 23. An opening / closing spring 27 and the like having a lower end portion connected and an upper end portion connected to the handle lever 18 are provided.

  Further, the tripping mechanism 16 latches the latch receiver 28 that latches the right end of the latch 21 in FIG. 1, and the trip crossbar 29 that faces the overcurrent tripping device 7 of each pole. I have.

  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 27 through the toggle link 24 and brings the movable contact 3 into contact with the fixed contact 2 through the contact spring 13. When the operation handle 19 is opened in the right direction from this state, the toggle link 24 is reversed due to the dead center of the opening / closing spring 27, and the movable contact 3 is driven to open in the right direction via the holder 11, so that the circuit breaker is operated. 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 due to the heat generated by the heater conductor 8 and pushes the trip cross bar 29. As a result, the trip cross bar 29 rotates counterclockwise and disengages from the latch receiver 28. Therefore, the latch receiver 28 rotates clockwise and the engagement with the latch 21 is released. As a result, the latch 21 rotates counterclockwise, the dead center of the open / close spring 27 is generated, the toggle link 24 is inverted, and the circuit breaker is opened.

  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 32 by the magnetic flux of the current flowing through the heater conductor 8, and the trip cross bar 29 Press. 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 33 and the movable contact 34, and this arc is drawn into the arc extinguishing device 35 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 described below, a means for isolating the movable portion from the splash of the melt due to the arc heat is provided according to the present invention.

  That is, in FIG. 1, the mold case 14 includes a case main body 36, a middle cover 37 attached to the upper surface thereof, and a top cover 38 covering the upper surface of the middle cover 37. The removing device 7 and the arc extinguishing device 35 are housed in a case main body 36, and the opening / closing mechanism 15 and the tripping mechanism 16 integrally formed on the frame 17 are housed in a middle cover 37. 2 to 4 show the top cover 38, the middle cover 37, and the case body 36 separately.

  1 to 4, the attachment structure of the contact portion 4, the overcurrent tripping device 7, and the arc extinguishing device 35 in the case main body 36 is substantially the same as that of the prior art, but each pole is attached to the bottom of the middle cover 37. A straddling partition 39 is formed, and the opening / closing mechanism 15 and the tripping mechanism 16 are attached to the central pole portion on the partition 39. The partition wall 39 is provided with a slit 40, and the toggle link 24 is drawn downward through the slit 40.

  The middle cover 37 shown in FIG. 3 to which the opening / closing mechanism 15 and the tripping mechanism 16 are attached is mounted on the case main body 36 shown in FIG. 4 from above and connects the lower link 23 to the holder 11. In that case, as described in Patent Document 1, the connecting pin 41 is fixed to the lower link 23, and the connecting pin 41 is inserted into a groove (not shown) provided on the side surface of the holder 11. May be coupled to the holder 11.

  In the middle cover 37 of FIG. 3, it is preferable that the interior accessory 42 of the circuit breaker is accommodated in the side space of the opening / closing mechanism 15 as shown in FIG. 5. Thereby, while being able to carry out attachment holding of the interior accessory 42 easily, the interior accessory 42 can be protected also from adhesion of a molten material. In addition to the specified auxiliary contact 43 for detecting the open / closed state of the circuit breaker and the alarm contact 44 for detecting the trip state of the circuit breaker, the interior accessory 42 has a specified voltage for the circuit in which the circuit breaker is inserted. Examples include an undervoltage trip device that trips the circuit breaker when the voltage drops, a voltage trip device for remotely operating the circuit breaker, and the like (see JP-A-6-236726). The top cover 38 in FIG. 2 is finally attached to the middle cover 37.

  As shown in FIG. 1, by moving movable parts such as the opening / closing mechanism 15 and the tripping mechanism 16 in a middle cover separate from the case main body 36, these movable parts are isolated from the contact part 4, and arc heat The adhesion of the melt due to is suppressed. In that case, as shown in the figure, a partition wall 39 is formed at the bottom of the middle cover 37, and the toggle link 24 is connected to the holder 11 through a slit 40 provided in the partition wall 39, so that the movable part can be more reliably shielded. The slit 40 is kept in a minimum gap necessary for the operation of the toggle link 24. Further, as shown in FIG. 4, if the same insulating partition 45 as in the prior art is mounted in the case body 36 and the opening / closing mechanism 15 and the tripping mechanism 16 are shielded by the double partitions 39, 45, the movable part is protected. It will be even more certain.

It is a longitudinal cross-sectional view of the circuit breaker which shows embodiment of this invention. It is a longitudinal cross-sectional view of the top cover in FIG. It is a longitudinal cross-sectional view of the middle cover in FIG. It is a longitudinal cross-sectional view of the cover main body in FIG. It is a longitudinal cross-sectional view which shows the state which accommodated the interior accessory in the middle cover in FIG.

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 27 Opening / closing spring 35 Arc extinguishing device 36 Case body 37 Middle cover 38 Top Cover 39 Bulkhead 40 Slit 42 Interior accessories

Claims (2)

The movable contact is composed of a fixed contact and a movable contact. The movable contact is rotatably supported via an insulator holder, and an arc extinguishing device that extinguishes an arc generated in the contact. An open / close mechanism that opens and closes the movable contact, a trip mechanism that trips the lock of the open / close mechanism, and an overcurrent trip device that detects the overcurrent and activates the trip mechanism. In the circuit breaker connected to the holder via a toggle link that reverses when the dead center of the open / close spring is exceeded,
The mold case is divided into a case main body, a middle cover attached to the upper surface of the case main body, and a top cover that covers the upper surface of the middle cover, and a slit is provided in part on the bottom of the middle cover. The contact portion and the arc extinguishing device are housed in the case body, and the opening / closing mechanism and a tripping mechanism for releasing the lock of the opening / closing mechanism are housed in the middle cover, and A circuit breaker, wherein the toggle link is connected to the holder through a slit provided . The circuit breaker according to claim 1, wherein an interior accessory is housed in a side of the opening / closing mechanism in the middle cover.

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