JPH02257535A - Circuit breaker - Google Patents

Abstract

PURPOSE:To enhance the cutoff ability by providing a surrounding wall, which encircles a contact couple and opens in different direction from the tripping mechanism side, and by forming in the body case an arc extinguishing chamber partitioned from the tripping mechanism part. CONSTITUTION:When an excessive abnormal current flows in a main circuit for example in the event of shortcircuiting, a tripping mechanism 18 rotates a moving contact piece 14 upward to open a contact couple 12, and arcs are generated between two contacts 13a, 14a of the contact couple 12 to cause generation of high-temp., high pressure arc gas. This gas is cooled at a filter 27 and released to the outside of the body case 11 upon seizure of metal contained in the gas. As a surrounding wall lies on the right side of the contact couple 12, the pressure of the arc gas blows through from the right side of the arc to the left to elongate the arc. In this manner arc gas is generated in an arc extinguishing chamber 17 partitioned from the tripping mechanism 18 and discharged out of an opening 23a in the direction opposite to the tripping mechanism 18, wherein chips of molten metal will never spatter onto the tripping mechanism 18.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a circuit breaker that opens a pair of contacts to cut off the current when an abnormal current flows in a main circuit.

(Prior Art) As shown in FIG. 3, a circuit breaker, for example, a wiring breaker, is equipped with a contact pair 4 consisting of a fixed contact 2 and a movable contact 3 in a main body case 1 made of an insulating material. When an abnormal current such as a short circuit current flows through the circuit, the trip mechanism 5 separates the movable contact 3 from the fixed contact 2 to open the main circuit. The arc that occurs between both contacts 2 and 3 when the circuit is broken in this way is the fourth
The arc is stretched and extinguished by an arc extinguishing device 7 consisting of a plurality of deion grids 6 as shown in the figure.

(Problem to be Solved by the Invention) By the way, in the case of the circuit breaker for wiring as described above, especially when cutting off a large current, the temperature rises due to the evaporation of the surrounding metal due to the generation of a cutting arc.

High pressure arc gas is generated. In this case, with the conventional configuration described above, metal vapor or molten metal pieces contained in the arc gas will also scatter toward the trip mechanism section 5, and there is a risk that this metal will adhere to the components of the trip mechanism section 5. was there. If metal adheres to the components of the trip mechanism section 5 in this way, there will be problems such as interference with the operation of the trip mechanism section 5.

The present invention has been made in view of the above circumstances, and its purpose is to provide a circuit breaker that can prevent metal vapor or molten metal pieces contained in arc gas from adhering to the components of the trip mechanism. .

[Structure of the Invention] (Means for Solving the Problems) The circuit breaker of the present invention is provided with an enclosing wall portion that surrounds the contact pair and opens in a direction different from the trip mechanism side. The feature is that an arc extinguishing chamber is formed in the trip mechanism section.

(Function) According to the above means, the breaking arc between the contact pair is generated in the arc extinguishing chamber that is separated from the trip mechanism section in the main body case, and the arc gas generated along with this occurs through the opening in the surrounding wall. It starts to be discharged from the part. Therefore, metal vapor or molten metal pieces contained in the arc gas will not be scattered toward the trip mechanism and will not adhere to the components of the trip mechanism.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2.

First, in FIG. 1 showing the overall configuration, reference numeral 11 denotes a main body case made of an insulating material, and a contact pair 12 is disposed inside the main body case located on the left side in the figure. This contact pair 12
consists of a fixed contact 13a at the tip of the fixed contact 13, and a movable contact 14a at the tip of the movable contact 14 that moves toward and away from the fixed contact 13a. Then, the fixed contact 1
3 is attached to the inner bottom of the main body case 11 in a state where it is electrically connected to the connection terminal 15 on the left side of the main body case 11, while the movable contact 14 is electrically connected to the connection terminal 16 on the right side of the main body case 11. The identification contact 13 is provided so as to come into contact with and separate from the identification contact 13 while being connected to the identification contact 13. In this case, the movable contactor 14 is bent into an abbreviated shape, and its distal end portion is a gently curved circular arc portion 14b. Further, the contact pair 12 is arranged in an arc extinguishing chamber 17, which will be described later, and which is provided on the left side of the main body case 11 in the drawing. Reference numeral 18 denotes a trip mechanism section located on the right side of the arc extinguishing chamber 17, which is a toggle mechanism that rotates the movable contact 14 about the shaft 19, as is well known although not shown in detail. Link mechanism 20, manual opening/closing operation handle 21, movable contact 14 and connection terminal 1
6 and the tripping device 22 and the like.

The trip mechanism section 18 normally closes the main circuit by bringing the movable contact 14a into contact with the fixed contact 13a, and when an abnormal current flows in the main circuit, the tripping device 22 closes the main circuit. Upon detection, the toggle link mechanism 20 is activated, the movable contact 14 is rotated upward, and the main circuit is opened.

Now, the arc extinguishing chamber 17 will be described with reference also to FIG.

This FIG. 2 shows the surrounding wall portion 23. As shown in FIG. This surrounding wall part 23
is constructed by screwing together two divided walls 24 and 25 made of, for example, insulating material butt against each other, and has a box shape as a whole with an opening 23a opening on the left side in the figure. A rectangular through hole 23b is formed in the upper surface of the surrounding wall portion 23 by matching the U-shaped notches formed in the two dividing walls 24 and 25, respectively. Similarly, a through hole 23c (see FIG. 1) is also provided on the lower surface of the surrounding wall 23.
is formed. As shown in FIG. 1, the surrounding wall section 23 configured in this manner is disposed within the main body case 11 so as to open toward the left side, which is a direction different from that of the trip mechanism section 18.

At this time, the tip portion of the fixed contact 13 has a through hole 23c.
The arc-shaped portion 14 on the tip side of the movable contact 14 penetrates through the
b comes to pass through the through hole 23b, so that the contact pair 1
2 is surrounded by a surrounding wall part 23. In this case, the through hole 2.3b is connected to the arcuate portion 1 of the movable contact 14.
The size is set to allow some room for 4b to rotate.

By arranging the surrounding wall portion 23 as described above, the inside of the surrounding wall portion 23 becomes an arc extinguishing chamber 17 that is separated from the trip mechanism portion 18 within the main body case 11. Incidentally, reference numeral 26 denotes an arc runner supported by the inner wall of the surrounding wall portion 23 and disposed within the arc extinguishing chamber 17, which has a torsion coil spring shape as is well known.

Further, an exhaust port 11a is formed in the left side wall portion of the main body case 11 facing the opening 23a of the surrounding wall portion 23, and a filter 27 is attached to block the exhaust port 11a.

Next, the operation of the above configuration will be explained.

For example, if an excessive abnormal current flows in the main circuit due to a short circuit accident, the trip mechanism 18 will cause the movable contact 1 to
4 is rotated upward to open the contact pair 12. At this time, an arc occurs between both contacts 13a and 14B of the contact pair 12, resulting in a high temperature.

High pressure arc gas is generated. This arc gas is discharged from the M opening 23a of the surrounding wall 23 to the left side in the figure, is cooled by the filter 27, and the metal contained in the gas is captured before being discharged to the outside of the main case 11. Further, since the immediate right side of the contact pair 12 where the arc is generated is a wall formed by the surrounding wall part 23, the pressure of the arc gas acts on the arc so as to blow it from the right side to the left side, which stretches the arc. It also acts as a force.

According to this embodiment, arc gas is generated in the arc extinguishing chamber 17 that is separated from the trip mechanism section 18, and flows from the opening 23a of the surrounding wall section 23 to the trip mechanism section 1.
8 is now ejected in the opposite direction. Therefore, unlike the conventional method in which there is a risk that the metal vapor or metal molten pieces contained in the arc gas may also scatter to the trip mechanism section 5 side, the metal vapor or metal molten pieces contained in the arc gas are removed from the trip mechanism section 18. It will not scatter to the side and will not adhere to the components of the trip mechanism section 18. As a result, malfunctions of the trip mechanism 18 due to metal adhesion to the components of the trip mechanism 18 can be prevented, and reliability is improved. Furthermore, as described above, the arc gas also has the effect of stretching the arc, so that the cut-off time can be shortened and the cut-off ability can be improved.

[Effects of the Invention] As is clear from the above description, the circuit breaker of the present invention can prevent metal vapor or molten metal pieces contained in arc gas from adhering to the components of the trip mechanism. This has excellent effects in that it is possible to eliminate the adverse effect on the trip mechanism due to its adhesion, and it is also possible to shorten the shutoff time and improve the shutoff ability.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a side view of the entire body case with a part cut away;
FIG. 2 is a perspective view of the surrounding wall, FIG. 3 is a view corresponding to FIG. 1 showing a conventional example, and FIG. 4 is a perspective view of the same arc extinguishing device. In the drawing, 11 is a main body case, 12 is a contact pair, 13 is a fixed contact, 13a is a fixed contact, 14 is a movable contact, 14a
14b is a movable contact, 14b is an arcuate portion, 17 is an arc extinguishing chamber, 18 is a trip mechanism portion, 23 is a surrounding wall portion, 23a is an opening portion, 23
b, 23c are through holes, 24.25 is a dividing wall, and 26 is an arc runner.

Claims (1)

[Claims] 1. A device comprising a contact pair for opening and closing the main circuit and a trip mechanism part for opening and closing the contact pair when an abnormal current flows in the main circuit, which surrounds the contact pair and operates the trip mechanism. A circuit breaker characterized in that an arc extinguishing chamber separated from the trip mechanism section is formed in the main body case by providing a surrounding wall section that opens in a direction different from the mechanism section side.