JP7493879B2 - Circuit breaker - Google Patents

Description

The present invention relates to a circuit breaker.

As described in Patent Document 1, it is known to use a barrier that exhausts to the outside the high-temperature arc that occurs in the arc extinguishing chamber during an overload or when the contacts are opened and closed, and prevents the intrusion of foreign matter from the outside.

Japanese Utility Model Application Publication No. 5-23388

Generally, the barrier is thin and made of insulating paper, fiber, or metal. When insulating paper or fiber is used, the barrier itself is inexpensive, but there is a risk of the barrier burning out due to arcing. When metal is used, there is a risk of a short circuit occurring between the moving contact and the barrier when the contacts are opened.

The inventor of this invention has studied this issue thoroughly and attempted to solve it. The problem that this invention aims to solve is to protect the barrier from arc gas in a molded circuit breaker.

To solve the above problem, a circuit breaker for wiring that has a housing formed by attaching a cover to a base, a fixed contact fixed within the housing, a movable contact that can move from a position in contact with the fixed contact to a position where it is not in contact with the fixed contact, and a barrier that is attached to an opening for releasing arc gas is provided on the cover, and the circuit breaker for wiring that has a protective part that covers at least a part of the barrier from the inside of the housing.

It is also preferable that the protective portion of the cover extends downward at least to a height position near the terminal base.

It is also preferable that the protective portion of the cover extends downward to a height below the terminal base.

It is also preferable to provide an arc extinguishing device in the housing, the arc extinguishing device having a grid made of a magnetic material that extends the arc, and a protective part provided on the cover being positioned between the barrier and the grid.

It is also preferable that the protective section be configured with an exhaust hole that is open downwards.

It is also preferable that the barrier is made of metal, and the protective portion extends downward to below the height of the movable contact when the distance between the movable contact and the barrier is shortest within the movable range of the movable contact.

The present invention makes it possible to protect the barrier from arc gas in a molded circuit breaker.

FIG. 1 is a perspective view of a molded case circuit breaker according to an embodiment. FIG. 13 is a perspective view showing an example of a cover provided with a protective portion. 3 is a cross-sectional view of the front end side of the molded circuit breaker shown in FIG 1 along line III-III, but only the front side of the molded circuit breaker is shown. 4 is a partially enlarged view of the barrier and its surroundings in FIG. 3, with dashed lines indicating the height of the terminal base and the like. FIG. 5 is a perspective view of the area shown in FIG. 4 . A cross-sectional view of the protective section taken along the line VI-VI. However, only the right side of the molded case circuit breaker is shown.

The following describes an embodiment of the invention. As can be seen from Figs. 1 to 3, the molded circuit breaker 1 of this embodiment has a housing 10 formed by attaching a cover 12 to a base 11, a fixed contact 21 fixed within the housing 10, a movable contact 25 that can move from a position in contact with the fixed contact 21 to a position where it is not in contact, and a barrier 41 attached to an opening for releasing arc gas. In addition, the molded circuit breaker 1 has a protective portion 13 on the cover 12 that covers at least a portion of the barrier 41 from the inside of the housing 10. This makes it possible to protect the barrier 41 from the arc gas.

Here, the up-down, front-back, and left-right directions in the specification will be explained. The side on which the handle 91 used to turn the molded-case circuit breaker 1 on and off is provided is the upper side. The opposite side, which is the side on which the surface facing the mounting surface of a distribution board or the like is provided, is the lower side. The front-back direction is the direction in which the terminals of the molded-case circuit breaker 1 are located at both ends. In this embodiment, the side on which the fixed contactor 23 having the terminal base 22 and the fixed contact 21 is located is the front side. The direction perpendicular to the up-down and front-back directions is the left-right direction.

Next, an overview of the molded case circuit breaker 1 of the embodiment will be described. In the molded case circuit breaker 1 of the embodiment, most of the components constituting the main functions are housed in the base 11. For example, the base 11 houses a movable contactor 26 having a movable contact 25 and a fixed contact 21 that can come into contact with the movable contact 25. The base 11 also houses an arc extinguishing device that can suppress malfunctions caused by arcs that occur when the fixed contact 21 and the movable contact 25 are pulled apart while a current is flowing. The arc extinguishing device of the embodiment includes a grid 71 made of a magnetic material that extends the arc. Note that the grid 71 of the embodiment is arranged so that multiple metal plates are spaced apart.

The molded-case circuit breaker 1 is provided with an opening for discharging arc gas so that gas generated by an arc caused by peeling the movable contact 25 from the fixed contact 21 while a current is flowing can be discharged to the outside. A barrier 41 is attached to the opening for discharging arc gas to prevent dust and dirt from entering the housing 10 from the outside. The barrier 41 usually has multiple holes 42 that are used to discharge gas.

To protect this barrier 41 from the effects of the arc, the molded-case circuit breaker 1 of the embodiment has a protective section 13 on the cover 12, which is disposed in a position that obstructs the arc from traveling from the arc generation point toward the barrier 41. Because this protective section 13 is part of the cover 12, it is possible to protect the barrier 41 without increasing the number of parts. The cover 12 of the embodiment is made of resin.

Normally, the barrier 41 discharges the arc gas to the outside from above the terminal seat 22. For this reason, it is preferable that the protective part 13 provided on the cover 12 extends downward at least to a height position near the terminal seat 22 (see Figure 4). This is because the protective part 13 can be positioned on the path of the arc, and the barrier 41 can be protected efficiently. If the protective part 13 provided on the cover 12 is configured to extend downward to a height position below the terminal seat 22, the barrier 41 can be protected more efficiently.

When an arc extinguishing device is provided inside the housing 10, it is preferable that the arc extinguishing device is provided with a grid 71 made of a magnetic material that stretches the arc, and that the protective part 13 provided on the cover 12 is positioned between the barrier 41 and the grid 71. This is because the protective part 13 can efficiently block the arc gas generated by the arc stretched by the grid 71.

In addition, since the arc is extended upward by the grid 71, it is preferable to particularly protect the upper part of the barrier 41. In this regard, the protective part 13 provided on the cover 12 is configured to extend from the top to the bottom, and is therefore suitable for protecting the barrier 41.

The protective part 13 may be provided with an exhaust hole 14. By forming the exhaust hole 14, the exhaust property is improved, and the short circuit performance can be improved. The exhaust hole 14 provided in the protective part 13 may be formed in a slit shape or a through hole shape, but it is preferable to form it so as to correspond to each hole 42 provided in the barrier 41. Also, as can be understood from Figures 5 and 6, it is preferable that the protective part 13 is configured with an exhaust hole 14 that is open downward. This is because it is advantageous for efficient molding, since the cover 12 can be molded by being pulled out in one direction during molding, etc.

When the barrier 41 is made of metal, it is preferable that the protective portion 13 extends downward to below the height of the movable contact 25 when the distance between the movable contact 25 and the barrier 41 is the shortest within the movable range of the movable contact 25. This is because if the arc is prevented from reaching the barrier 41 made of metal when the movable contact 25 is in the open position, it is possible to prevent electrical conduction through the barrier 41 to the terminal base 22 even when the contact is open.

The present invention has been described above using examples of embodiments, but the present invention is not limited to the above embodiments and can be implemented in various forms.

1 Distribution circuit breaker 10 Housing 11 Base 12 Cover
13. Protective section
14 exhaust holes
21 Fixed contact 22 Terminal base 25 Movable contact 41 Barrier 42 Hole 71 Grid

Claims (7)

A molded-case circuit breaker having a housing formed by attaching a cover to a base, a fixed contact fixed within the housing, a movable contact movable from a position in contact with the fixed contact to a position not in contact with the fixed contact, and a barrier attached to an opening for releasing arc gas,
The barrier is separate from the cover.
A wiring circuit breaker having a cover equipped with a protective part that covers at least a portion of the barrier from the inside of the housing. 2. The circuit breaker according to claim 1, wherein the barrier extends to a height equal to or lower than the height of the terminal base . 3. The molded case circuit breaker according to claim 1, wherein the protective portion of the cover extends downward at least to a height position in the vicinity of the terminal base. 4. The molded case circuit breaker according to claim 1, wherein the protective portion of the cover extends downward to a height position equal to or lower than that of the terminal base. An arc extinguishing device is provided in the housing.
The arc extinguishing device includes a grid made of a magnetic material that extends the arc;
5. The molded case circuit breaker according to claim 1, wherein the protective portion provided on the cover is located between the barrier and the grid. A molded-case circuit breaker having a housing formed by attaching a cover to a base, a fixed contact fixed within the housing, a movable contact movable from a position in contact with the fixed contact to a position not in contact with the fixed contact, and a barrier attached to an opening for releasing arc gas,
The cover is provided with a protective portion that covers at least a part of the barrier from the inside of the housing,
The protective part is a wiring circuit breaker with an open exhaust hole at the bottom. A molded-case circuit breaker having a housing formed by attaching a cover to a base, a fixed contact fixed within the housing, a movable contact movable from a position in contact with the fixed contact to a position not in contact with the fixed contact, and a barrier attached to an opening for releasing arc gas,
The cover is provided with a protective portion that covers at least a part of the barrier from the inside of the housing,
The barrier is constructed using a metal,
A circuit breaker in which the protective portion extends downward to below the height position of the movable contact when the distance between the movable contact and the barrier is shortest within the movable contact's range of motion.