JPH0547924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a power switch that switches and closes current, and particularly relates to an improvement in shearing performance.

Examples of switches to which this invention is mainly applied include electromagnetic contactors, wiring switches, and disconnectors.

[Prior Art] First, an example of a conventional electromagnetic contactor will be described with reference to FIG. Since a conventional electromagnetic contactor is bilaterally symmetrical, FIG. 1 shows a cross section of one side of the contactor. In Fig. 1, 1 is a mounting base made of plastic, 2 is a fixed core laminated with silicon steel plates on this mount, and 3 is a movable core installed opposite the fixed core 2 and also laminated with silicon steel plates. an iron core; 4 is an operation coil that applies a driving force to attract the movable core 3 and fixed core 2 against a tripping spring (not shown); 5 is a crossbar made of plastic and having a square window; A movable iron core 3 is held at its lower end. 6 is a movable contact inserted into a corner window of the cross bar 5 and held by a push spring 7; 6A is a movable contact provided on this movable contact 6; 8 is a movable contact facing the movable contact 6; provided,
8A is a fixed contact provided on the fixed contact 8 for supplying current, and 8C is a terminal portion of the fixed contact 8.

9 is a terminal screw for connecting the electromagnetic contactor main body with an external circuit, 10 is a base on which the fixed contact 8 is attached, and 11 is a cover that covers the top surface of the electromagnetic contact, and inside it is a fixed contact 8A and a movable contact. A metal arc extinguishing plate 13 made of a magnetic material is provided to extinguish the arc 12 that occurs between 6 A and FIG. There is. The metal arc-extinguishing plate 13 is configured as a U-shaped frame that stands upright over the fixed contact 8A, and is provided with a cutout end 14 in the vicinity of the fixed contact 8, through which it is inserted.

With the above configuration, in this conventional electromagnetic contactor, when the operation coil 4 is demagnetized, the movable core 3 is separated from the fixed core 2 by a tripping spring (not shown), and the crossbar 5 also returns to the state shown in FIG. When the fixed contact 8A and the movable contact 6A open, an arc 12 is generated between the fixed contact 8A and the movable contact 6A.
However, this arc 12 is extinguished at the current zero point by the metal arc extinguishing plate 13, and the current is briefly interrupted.

The arc 12 extinguishing process in this conventional electromagnetic contactor will be explained in more detail with reference to FIG. 3 showing a cross section of the arc extinguishing chamber. Arc extinguishing plate 13
It is attracted to the arc 12A and stretched like the extension arc 12A. When the arc is stretched like this extended arc 12A, the arc voltage becomes high.
Dielectric breakdown occurs between the notch end 14 of No. 3 and the movable contact 6A, and the arc 12A is divided into two arcs 12B,
12C, and the two arcs 12B and 12C are extinguished at the current zero point. In conventional electromagnetic contactors that extinguish arcs through such a process, electric field concentration occurs on the metal arc extinguishing plate 13 and an arc 12C is generated at the tip 14, which has poor thermal conductivity, resulting in deterioration of the shearing performance. It was supposed to form the main cause.

[Summary of the invention]

This invention was made to eliminate the drawbacks of the conventional ones as described above, and includes a movable contact joined to a movable contact, a fixed contact facing the movable contact, and a first contact to which the fixed contact is joined. a third surface provided on the opposite side of the fixed contact and facing the first surface, one end of which is a terminal; an arc drive side end of the first surface and a non-terminal side end of the third surface. a fixed contact comprising a second surface connecting the first surface and the second surface, the boundary between the first surface and the second surface forming a curved surface; and a metal arc-extinguishing plate that faces the boundary portion and further extends in the direction of the third surface, and the distance between the second surface and the metal arc-extinguishing plate increases as it approaches the third surface. The purpose is to obtain a power switch with improved shearing performance by configuring it to be larger.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. The power switch according to one embodiment of the present invention is the same as the conventional one shown in FIGS. 1 to 3 except for the fixed contact 8 and the metal arc-extinguishing plate 13, so the main parts are shown in FIG. shows. In the figure, 81 is the first surface to which the fixed contact 8A is joined, and 83 is the anti-fixed contact 8.
A third surface that is provided on the A side and faces the first surface 81 and has one end as the terminal 8C; 82 is the arc drive side end of the first surface 81 and the non-terminal side end of the third surface 83; It is the second surface that connects these first, second, and third
The fixed contact 8 is constituted by the surfaces 81, 82, and 83. In addition, the first surface 81 and the second surface 82
The nose angle is less than 90 degrees, and these surfaces 81,
The boundary portion 8B of 82 has a curved surface. In this example, the fixed contact 8 has a Z-shaped cross section. On the other hand, the metal arc-extinguishing plate 13 is erected along the opening direction of the movable contact 6A, and faces the end of the movable contact 6 and also faces the boundary 8B between the first surface 81 and the second surface 82. It is further arranged to extend in the direction of the third surface 83. Further, the distance between the second surface 82 and the metal arc-extinguishing plate 13 increases as it approaches the third surface 83.

Next, the operation will be explained. The arc 12 generated between the movable contact 6A and the fixed contact 8A is first attracted to the magnetic metal arc extinguishing plate 13, and the arc 12A
, and the arc voltage is increased. As a result, dielectric breakdown occurs and the arc 12A is divided into two arcs 12B and 12C. When the arc 12A is divided into two arcs 12B and 12C in this way, a current flows through the metal arc extinguishing plate 13, so
The divided arcs 12B and 12C are connected to the metal arc extinguishing plate 1
The arcs 12D and 12E are further driven by the magnetic field created by the current flowing through them, and are extinguished at the current zero point, causing the current to be cut off. In this invention, the second surface 82 of the fixed contact
Since the distance between the metal arc-extinguishing plate 13 and the metal arc-extinguishing plate 13 is configured to increase as it approaches the third surface 83,
The distance between the fixed contact 8 and the metal arc-extinguishing plate 13 is shortest between the boundary 8B between the first surface 81 and the second surface 82 of the fixed contact 8 and the metal arc-extinguishing plate 13. Therefore, the arc formed between the metal arc extinguishing plate 13 and the fixed contact 8A is magnetically driven downward by the magnetic field created by the current flowing through the metal arc extinguishing plate 13, and the arc 1
2C, the metal arc-extinguishing plate 13 sticks to the boundary 8B between the first surface 81 and the second surface 82 of the fixed contact 8, which has the shortest distance. Furthermore, in this invention, the first surface 81 and the second surface 8 of the fixed contact 8
Since the boundary part 8B of 2 is formed in a curved shape,
The legs of the arc 12E are formed at the boundary portion 8B where the electric field strength is low and at the flat plate portion of the metal arc extinguishing plate 13. Therefore,
Excellent breaking performance can be obtained. According to this embodiment, since the arc is extinguished as described above, electric field concentration does not occur as in the conventional example shown in FIG.
Further, since no arc is generated at the tip portion 14, which has poor thermal conductivity, extremely excellent shear cutting performance can be exhibited.

In the above embodiments, the case where the metal arc-extinguishing plate 13 is flat has been mainly explained, but it is also possible to have a U-shape as shown in FIG. In this case, the side wall 1 of the cover 11 shown in FIG.
Since it is possible to reduce the arc heat damage caused by repeated cycles of 1A, it is also possible to prevent short circuits between phases caused by holes in the side wall 11A.

Further, in the above embodiment, the case where the angle between the first surface 81 and the second surface 82 is smaller than 90 degrees is shown, but as shown in FIG. The angle formed by the metal arc-extinguishing plate 13 is 90 degrees, and the distance between the second surface and the metal arc-extinguishing plate 13 increases as it approaches the third surface.
Even if it is provided at an angle, the same effect as in the above embodiment can be obtained.

Furthermore, in the above explanation, only an example in which the present invention is applied to a power switch that opens and closes the contacts using a magnet, that is, an electromagnetic contactor, is described. It is obvious that the present invention can also be applied to other power switches.

〔Effect of the invention〕

As described above, according to the present invention, a movable contact joined to a movable contact, a fixed contact facing the movable contact, a first surface to which the fixed contact is joined, and a side provided on the side opposite to the fixed contact. facing the first side,
It consists of a third surface, one end of which is a terminal, and a second surface that connects the arc drive side end of the first surface and the non-terminal side end of the third surface, and the first surface and the second surface a fixed contact whose boundary part forms a curved surface, and a third surface which is erected along the opening direction of the movable contact, and which faces the end of the movable contact and also faces the boundary part. Since the power switch is equipped with a metal arc-extinguishing plate extending in the direction, and the distance between the second surface and the metal arc-extinguishing plate increases as it approaches the third surface, the power switch has improved shearing performance. There is an effect that can be obtained.

[Brief explanation of drawings]

Figure 1 is a sectional view showing a conventional power switch;
The figure is an enlarged perspective view of the main parts of the power switch shown in Figure 1, Figure 3 is an explanatory diagram for explaining the arc extinguishing operation in the conventional power switch, and Figure 4 is an example of the present invention. An explanatory diagram showing the main parts of the power switch according to the embodiment and its operation, and FIGS. 5 and 6 are a perspective view and a side view, respectively, showing other embodiments of the present invention. In the figure, 6 is a movable contact, 6A is a movable contact, 8 is a fixed contact, 8A is a fixed contact, 8C is a terminal, 81 is a first surface, 82 is a second surface, 83 is a third surface, 8B is a boundary between the first surface 81 and the second surface 82, 12, 12A to 12E are arcs, and 13 is a metal arc-extinguishing plate. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A movable contact joined to a movable contact, a fixed contact facing the movable contact, a first surface to which the fixed contact is joined, and a first surface provided on the side opposite to the fixed contact. a third surface facing the terminal and having one end serving as a terminal;
A fixed contact consisting of a second surface connecting the arc drive side end of the surface and the non-terminal side end of the third surface, the boundary between the first surface and the second surface forming a curved surface, and the above-mentioned fixed contact. a metal arc-extinguishing plate that is erected along the opening direction of the movable contact, faces the end of the movable contact, faces the boundary, and further extends in the direction of the third surface; The distance between the surface and the metal arc-extinguishing plate is the third
A power switch configured to increase in size as it approaches the surface. 2. The power switch according to claim 1, wherein the angle formed by the first surface and the second surface is 90 degrees or less. 3. The power switch according to claim 2, wherein the fixed contact has an S-shaped or Z-shaped cross section.