JPH0339364B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switch that switches on and off current, and particularly to an improvement in its arc-extinguishing function.

For example, in a switch used as an electromagnetic contactor or a molded circuit breaker, how to improve the breaking performance of the switch is a matter of greatest interest to those skilled in the art.

FIG. 1 shows an example of an electromagnetic contactor as a conventional switch. The contactor shown in the figure includes a mounting base 10, a fixed core 12, a movable core 14, an operating coil 16, a crossbar 18, a movable contact 20 to which a movable contact 20A is joined, a presser spring 22, and a fixed contact 24A. The terminal includes a fixed contact 24, a terminal screw 26, a base 28, a cover 30, and the like.
The movable contactor 20 is pressed against the lower edge surface of the square window of the cross bar 18 by a retaining screw 22, and the cross bar 18 is further connected to the movable iron core 14.
Then, when the operating coil 16 is energized, the movable core 14 is magnetically attracted to the fixed core 12 against a separation spring (not shown), which causes the movable contact 20A to
The fixed contact 24A is configured to come into contact with the fixed contact 24A.

Here, when the power to the operating coil 16 is cut off, the movable contact 20A and the fixed contact 24A are separated by the action of the separation spring. At this time, an arc 32 is generated between the contacts 20A and 24A, but this arc 32 is extinguished by the metal arc extinguishing plates 34 and 36, thereby interrupting the current.

FIG. 2 shows the state of the metal arc-extinguishing plates 34, 36 and the vicinity of the fixed contact 24A. Further, FIG. 3 shows a process in which an arc 32 generated between both contacts 20A and 24A is extinguished. Here, both contacts 20A, 2
The arc 32 generated between 4A and 4A is attracted to the first metal arc-extinguishing plate 34 made of a magnetic material and is elongated as shown by the reference numeral 32A. In this case, if the fixed contact 24 is U-shaped as shown in FIG.
The magnetic field created by the current flowing through the stationary contact 24 drives the arc 32, thereby stretching the arc 32 longer. As the arc 32 is stretched, the arc voltage increases, so dielectric breakdown occurs between the fixed contact 24 and the first metal arc extinguishing plate 34 and between the first metal arc extinguishing plate 34 and the movable contact 24A, and the arc 32B has two arcs 32B and 32C
It is divided into two parts.

One of the divided arcs 32B is connected to the movable contact 2
It is cooled between 0A and the first metal arc-extinguishing plate 34.
The other divided arc 32C is attracted to the second metal arc extinguishing plate 36 and is driven by the magnetic field created by the current flowing through the fixed contact 24, resulting in an arc 32C.
Stretched as shown in 2D. this arc 3
When 2D is stretched and the arc voltage increases,
Arc 32D is divided into two arcs 32E and 32F. Arc 32 will eventually become 32B, 32
E and 32F, the arc is extinguished at the current zero point, and the current is cut off.

By the way, the arc 32B generated between the movable contact 20A and the first metal arc-extinguishing plate 34 receives the driving force F1 of the magnetic field generated by the current flowing through the first metal arc-extinguishing plate 34, as shown in FIG. The arc 32E generated between the first metal arc-extinguishing plate 34 and the second metal arc-extinguishing plate 36 is caused by the magnetic field created by the current flowing through the first metal arc-extinguishing plate 34. The arc 32F generated between the second metal arc extinguishing plate 36 and the fixed contact 24 receives a force F3 due to the magnetic field created by the current flowing through the arc 32F. And power
Since F2 and F3 are approximately the same in size and opposite in direction, the arc 32E generated between the first metal arc extinguishing plate 34 and the second metal arc extinguishing plate 36 is It is easy to get stuck between the arc-extinguishing plate 34 and the second metal arc-extinguishing plate 36. When traveling under the driving force F1 like the other arc 32B, the arc is extinguished quickly because it is cooled more strongly by the air and the first metal arc extinguishing plate 34 as it travels. Moreover, it becomes reliable and the interrupting performance can be ensured. However, when the two types of forces F2 and F3 cancel each other out and reach a stalemate, as in Arc 32E, the cooling effect of running cannot be obtained, and as a result, the conventional switch has the drawback of not being able to obtain sufficient breaking performance. It was bringing.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to divide the arc into two parts by the first metal arc-extinguishing plate, and to prevent the arc between one of the divided parts, the movable contact, This switch is capable of reliably preventing a decrease in breaking performance by driving the arc to strongly cool it and also driving the arc between it and the other second metal arc extinguishing plate to cool it. It is about providing.

In order to achieve the above object, the present invention includes a fixed contact to which a fixed contact is joined, a movable contact to which a movable contact is joined, and a vertical direction from the upper side of the fixed contact to approximately the height of the movable contact joining part. The arc that occurs when the fixed contact and the movable contact are opened is
Guides and extinguishes one of the arcs divided by the first metal arc-extinguishing plate and the first metal arc-extinguishing plate provided on the opposite side of the movable contact with reference to the first metal arc-extinguishing plate. In the switch having a second metal arc-extinguishing plate, the folded portion is folded back in a U-shape from the lower end of the first metal arc-extinguishing plate and faces the second metal arc-extinguishing plate. One of the arcs separated by the first arc-extinguishing plate is connected to the movable contact and the first
between the folded part and the second metal arc extinguishing plate.
and a metal arc-extinguishing plate.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 4 and FIG. 5 show an embodiment of a main part of a switch according to the present invention. The switch, a part of which is shown in the same figure, is
Except for the first metal arc-extinguishing plate 34, it is the same as the conventional one described above. The first metal arc-extinguishing plate 34 is provided with a folded portion 34A folded back into a U-shape as shown in FIG. It is arranged so as to face the metal arc-extinguishing plate 34.

Here, in FIG. 5, both contacts 20A, 24
The arc 32 generated during A is attracted to the first metal arc-extinguishing plate 34 made of a magnetic material and is elongated as indicated by 32A. If the fixed contact 24 has a U-shape as shown in FIG.
The arc 32 is driven by the magnetic field created by the current flowing through it, thereby elongating the arc 32 further. As the arc 32 is stretched, the arc voltage increases, so dielectric breakdown occurs between the fixed contact 24 and the first metal arc-extinguishing plate 34 and between the first metal arc-extinguishing plate 34 and the movable contact 20A. As a result, arc 32A is divided into two arcs 32B and 32C. One of the divided arcs 32C is attracted by the second metal arc-extinguishing plate 36, and is driven by the magnetic field created by the current flowing through the fixed contact 24, thereby being stretched as shown by reference numeral 32D. . When this arc 32D is stretched and the arc voltage increases, the arc 32D is divided into two arcs 32E and 32F. Arc 32 is finally 3
Divided into three arcs 32B, 32E, 32F,
The arc 32F is extinguished between the arc lead portion 36B of the second metal arc extinguishing plate 36 and the fixed contact 24.

By the way, in the case of this invention, since the foot of the arc occurs at the folded portion 34A of the first metal arc-extinguishing plate 34, the first metal arc-extinguishing plate 34 and the second metal arc-extinguishing plate 3
The arc 32E generated between 6 and 6 receives the force F2 due to the magnetic field created by the current flowing through the folded portion 34A of the first metal arc-extinguishing plate 34, and along with this, the arc 32E generated between the second metal arc-extinguishing plate 36 and the fixed contact 24 The force F3 is received by the magnetic field created by the current flowing through the arc 32F generated during this period. Since the directions of F2 and F2 are the same, the arc 32E is strongly driven.

When the arc 32E is driven and travels upward in FIG. 5, cooling occurs with the air and the first and second metal arc extinguishing plates 34 and 36. Due to such cooling, the arc 32E loses its conductivity, and as a result, the arc 32E is extinguished at the inner part of the first metal arc extinguishing plate 34 and the second metal arc extinguishing plate 36.

On the other hand, the arc 32B is strongly cooled by driving by F1 as in the conventional case.

Therefore, in this embodiment, the first metal arc-extinguishing plate 34
The arcs 32B and 32E separated by the arcs 32B and 32E are strongly cooled as they travel, thereby providing excellent interrupting performance.
Note that the fixed contact 24 does not necessarily have to be U-shaped.

As described above, the switch according to the present invention has the first
Even with an extremely simple additional configuration in which a folded portion is provided on the first metal arc-extinguishing plate, the arcs separated by the first metal arc-extinguishing plate can be driven together and powerfully cooled. Therefore, the arc can be extinguished and the breaking performance of the switch can be reliably improved.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing an example of a conventional switch, Figure 2 is an enlarged view of the main part of the switch in Figure 1, and Figure 3 is a cross-sectional view of an example of a conventional switch.
FIG. 4 is a perspective view showing an embodiment of the main part of the present invention, and FIG. 5 is an explanatory diagram of the operation of the embodiment of the present invention. The same members in each figure are given the same reference numerals, 20 is a movable contact, 20A is a movable contact, 24 is a fixed contact, 24A is a fixed contact, 32, 32A to 32F are arcs, and 34 is a first metal extinguisher. The arc plate 36 is a second metal arc extinguishing plate, and 34A is a folded portion of the first metal arc extinguishing plate.

Claims (1)

[Claims] 1. A fixed contact to which a fixed contact is joined, a movable contact to which a movable contact is joined, and a fixed contact that is installed vertically from the upper side of the fixed contact to approximately the height of the movable contact joint part, and the fixed contact and the movable contact are separated. A first metal arc-extinguishing plate that divides the arc that sometimes occurs into two, and a first metal arc-extinguishing plate that is provided on the opposite side of the movable contact with this first metal arc-extinguishing plate as a reference. In the switch having a second metal arc-extinguishing plate that guides one side and extinguishes the arc, the first metal arc-extinguishing plate is folded back in a U-shape from the lower end of the first metal arc-extinguishing plate to the second metal arc-extinguishing plate. Opposing folded parts are provided, one of the arcs separated by the first metal arc-extinguishing plate is placed between the movable contact and the first metal arc-extinguishing plate, and the other is placed between the folded part and the second metal arc-extinguishing plate. A switch characterized in that it leads to, respectively.