JPH0831296A - Circuit breaker - Google Patents

Abstract

PURPOSE:To surely exhaust arc gas generated in current breaking. CONSTITUTION:The inside bottom of a case 1 in which a fixed contact 3 is set is cut and removed along the lower surface of the fixed contact 3 to form a exhaust gas passage 14 passing through an arc gas exhaust port 12. Exhaust of arc gas from a fixed contact setting part where exhaust of the arc gas is usually difficult is made easy, and drop in insulation caused by deposition of molten metal in the arc gas stayed on the case 1 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker such as a circuit breaker for wiring or an earth leakage breaker, and more particularly to an arc gas discharging means for the circuit breaker.

[0002]

2. Description of the Related Art FIG. 3 is a vertical cross-sectional view of a power supply side half portion showing a conventional configuration of the circuit breaker. In FIG. 3, case 1
In the insulating container consisting of the cover 2 and the cover 2, there is formed a shutoff portion made up of the fixed contactor 3 fixed to the case 1 and the movable contactor 5 which is driven to be opened / closed by the opening / closing mechanism 4. The arc chamber 6 is installed. Although the figure shows the cutoff portion in the central pole portion, the interior of the insulating container is divided into three-phase spaces by the phase gap walls, and each phase cutoff portion is housed in each space. Further, a partition wall 1a in the left-right direction is formed in the case 1 in the vicinity of the fixed contactor 3 to separate the blocking portion and the opening / closing mechanism portion. The fixed contactor 3 has a power source side terminal 3a integrally formed at one end, and the other end provided with the fixed contact 7 is folded back in a U shape to form a parallel conductor portion along the movable contactor 5.

A movable contact 5 having a movable contact 8 which comes in contact with and separates from a fixed contact 7 is rotatably supported by a case 1 through an insulator holder 9 and is opened and closed with an opening / closing shaft 9a integral with the holder 9 as a fulcrum. Driven. The arc-extinguishing chamber 6 has a structure in which a plurality of grids 11 are vertically stacked and supported on a pair of left and right support plates 10 of an insulating material. A letter-shaped notch is provided.
An arc gas discharge port 12 is provided in front of the shutoff portion, and an insulating protective plate 13 for preventing foreign matter from entering is attached to the arc gas discharge port 12. In such a circuit breaker, when the internal pressure of the breaking portion rises due to the generation of arc gas when the current is cut off, the rise of the internal pressure causes the protective plate 13 to rise.
Is pushed outward and curved as shown by the chain line in the figure, whereby arc gas is discharged from the opened arc gas outlet 12 toward the power source side of the circuit breaker as shown by the arrow.

[0004]

The arc gas generated when the electric current is cut off is discharged from the arc gas discharge port 12 as described above. This arc gas discharge hole 12 is shown in FIG.
As can be seen from the above, since the opening is at a position considerably higher than the installation portion of the fixed contactor 3, the arc gas diffused to the installation portion of the fixed contactor has conventionally been apt to stay in this portion. The arc gas contains a metal melt produced by melting the fixed / movable contacts 3 and 5 including the contacts 7 and 8 and the grid 11 by arc heat. It adheres to the inner surface and reduces the dielectric strength. Then, this invention aims at providing the circuit breaker which promoted discharge | emission of the arc gas from the fixed contact installation part, and prevented the fall of the dielectric strength due to the retention of the arc gas.

[0005]

SUMMARY OF THE INVENTION The present invention is a circuit breaker in which an arc gas discharge port is provided in front of a breaker portion which is composed of a fixed contactor fixed to a case and a movable contactor which is opened and closed by an opening / closing mechanism. In the above, the above object is achieved by forming an exhaust passage communicating with the arc gas discharge port between the case and the fixed contact. In that case, in the opening on the opposite side of the arc gas discharge port of the exhaust passage,
It is effective to prevent the exhaust passage from being clogged with the metal melt in the arc gas by providing an insulating shield plate having a vent hole having a diameter smaller than that of the exhaust passage. Further, it is preferable that the shielding plate is integrally formed with a partition wall provided between the blocking portion and the opening / closing mechanism.

[0006]

According to the present invention, the exhaust passage communicating with the arc gas discharge port is formed between the case and the fixed contact, and the arc gas diffused to the fixed contact installation portion is positively externalized through this exhaust passage. To discharge. As a result, the arc gas does not stay in the fixed contactor installation portion. In that case, the opening on the side opposite to the arc gas outlet of the exhaust passage,
That is, if an insulating material shield plate having a vent hole having a diameter smaller than that of the exhaust passage is provided on the arc gas inlet side of the exhaust passage, the shield plate can prevent the metal melt in the arc gas from entering the exhaust passage. Further, even if there is something that enters through the ventilation hole, it has a smaller diameter than the exhaust passage, so there is no possibility that it will be clogged and the exhaust passage will be blocked. The shield plate can be formed integrally with the partition wall provided between the shield portion and the opening / closing mechanism, thereby eliminating the need to provide the shield plate as a separate component.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. Here, FIG. 1 is a vertical sectional view of a power supply side half of the circuit breaker, and FIG. 2 is an enlarged perspective view of a fixed contact portion thereof. The same reference numerals are used for the parts corresponding to those of the conventional example, and the description of the same parts in particular is omitted. First, in FIG. 1, the inner bottom surface of each phase space of the case 1 is removed over the entire width along the lower surface of the fixed contactor 3, and the partition wall 1
An exhaust passage 14 is provided to reach the arc gas discharge port 12 from a. In order to support the fixed contact 3, a cylindrical boss 1b is integrally formed with the case 1 so as to project in the middle of the exhaust passage 14, and the boss 1b is in contact with the lower surface of the fixed contact 3. The width of the exhaust passage is widened on both sides of the boss 1b so that the boss 1b does not hinder ventilation.

Further, a partition wall 15 of a resin molded product is provided between the shutoff portion and the opening / closing mechanism 4. The partition wall 15 is shown in FIG.
As shown in FIG. 1, it comprises an upright partition wall body 15a and a bag-shaped cover portion 15b formed on the base portion thereof.
It is attached to the U-shaped portion of the fixed contactor 3 via 5b. A slit 16 is formed in the partition wall body 15 a, and the movable contact 5 is opened and closed in the slit 16. This partition wall 15 is installed in order to prevent the arc gas from diffusing and entering the installation space of the opening / closing mechanism 4 and preventing the metal melt in the arc gas described above from adhering to the opening / closing mechanism 3 and hindering its operation. In the present case,
A shield plate 17 is integrally formed on the partition wall 15, and two left and right rectangular ventilation holes 18 having a smaller diameter than the exhaust passage 14 are provided in the shield plate 17. The shielding plate 17 is the cover 1
5b extends horizontally from the upper part of the rear end of 5b to the partition wall 1a side.
As shown in FIG. 3, the opening 14 a of the exhaust passage 14 on the opposite side of the arc gas discharge port 12 is covered via a gap 19.
Other configurations are the same as the conventional example.

In such a circuit breaker, when an arc gas is generated when the current is interrupted and the internal pressure of the interrupting part rises, this arc gas pushes the protective plate 13 open as described above and is discharged from the arc gas discharge port 12 to the outside. However, the arc gas also tries to spread in all directions in the insulating container due to the pressure. Among them, the arc gas descending to the installation portion of the fixed contactor 3 is fixed as shown by the arrow.
Is collected in the exhaust passage 14, is guided to the arc gas discharge port 12 having a low pressure, and is discharged to the outside. Most of the arc gas directed toward the opening / closing mechanism 4 is blocked by the partition wall 15, but the arc gas that enters the back side from the slit 16 (FIG. 2) or the like is shown by arrows, such as the vent hole 18 and the gap 19 of the shield plate 17. It is collected in the exhaust passage 14 via the.

At this time, the metal melt in the arc gas is likely to accumulate if the opening 14a opened upward is left as it is, but it is blocked by the shield plate 17 in the illustrated structure, and the exhaust passage 14 is clogged with the metal melt. Never. Although some of the metal melt penetrates through the vent hole 18, since the vent hole 18 has a smaller diameter than the exhaust passage 14, the metal melt that has passed through the vent hole 18 has an exhaust passage 14.
Does not get stuck.

[0011]

According to the present invention, the exhaust passage communicating with the arc gas discharge port is formed between the case and the fixed contact, so that the exhaust of the fixed contact installation portion where the arc gas is likely to stay becomes good. It is possible to prevent the dielectric strength from being lowered due to the adhesion of the metal melt in the arc gas to the case. Further, in that case, if a shield plate of an insulator having a vent hole having a diameter smaller than that of the exhaust passage is provided at the opening of the exhaust passage on the side opposite to the arc gas outlet, clogging of the exhaust passage due to the metal melt in the arc gas is provided. It is effective in preventing it, and if the shielding plate is integrally formed with the partition wall provided between the blocking portion and the opening / closing mechanism, the desired configuration can be achieved without increasing the number of parts.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part of a circuit breaker showing an embodiment of the present invention.

FIG. 2 is a perspective view of a fixed contactor portion in FIG.

FIG. 3 is a longitudinal sectional view of a main part of a circuit breaker showing a conventional example.

[Explanation of symbols]

 1 Case 2 Cover 3 Fixed Contact 4 Opening / Closing Mechanism 5 Movable Contact 6 Arc-Extinguishing Chamber 12 Arc Gas Discharge Port 13 Protective Plate 14 Exhaust Passage 15 Partition Wall 17 Shielding Plate 18 Vent

Claims (3)

[Claims] 1. A circuit breaker in which an arc gas discharge port is provided in front of a breaker composed of a fixed contact fixed to a case and a movable contact driven to open / close by an opening / closing mechanism, wherein the case and the fixed contact are provided. A circuit breaker characterized in that an exhaust passage communicating with the arc gas discharge port is formed between the two. 2. The circuit breaker according to claim 1, wherein an insulating shielding plate having a vent hole having a diameter smaller than that of the exhaust passage is provided at an opening of the exhaust passage opposite to the arc gas discharge port. . 3. The circuit breaker according to claim 2, wherein the shielding plate is integrally formed with a partition wall provided between the breaking portion and the opening / closing mechanism.