JPH0787060B2 - Power switch - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric power switch for opening and closing electric power, and particularly to improvement of its contact.

[Conventional technology]

Power switches are widely used as electromagnetic contactors and circuit breakers.

As a conventional power switch, for example, an electromagnetic contactor as shown in FIG. 5 of Japanese Utility Model Application Laid-Open No. 192647/1982 is well known. Since the electromagnetic contactor is symmetrical, only the right cross section is shown. .

In the figure, (1) is a mounting base made of plastic, etc., (2) is a fixed iron core laminated with silicon steel plate on this mounting base, and (3) is arranged opposite to the fixed iron core (2). Similarly, a movable iron core laminated with a silicon steel plate, (4) an operating coil for applying a driving force that causes the movable iron core (3) and the fixed iron core (2) to be pulled off against a spring (not shown), and (5) ) Is a crossbar formed of plastic and having a square window, and a movable iron core (3) is held at its lower end. (6) is a movable contactor inserted into the square window of the crossbar (5) and held by a push spring (7),
(6a) is a movable contact provided on the movable contact (6),
(8) is a fixed contact that is provided so as to face the movable contact (6) and conducts current, (8a) is a fixed contact provided on this fixed contact (8), and (8b) is the same. The terminal part of this fixed contactor (8) is shown. (9) is a terminal screw for connecting the main body of the electromagnetic contactor to an external circuit, (10) is a base for mounting the fixed contactor (8), and (11) is a cover for covering the upper surface of the electromagnetic contactor, which is fixed inside the cover. A metal arc extinguishing plate (13) of magnetic material is provided to extinguish the arc (12) generated between the contact (8a) and the movable contact (6a). As can be seen more clearly, the movable contacts are opposed to each other, and they are cumulatively provided above the fixed contacts (8) in parallel with each other and at predetermined intervals.

The conventional power switch has the above-mentioned configuration, and its operation will be described below.

In the electromagnetic contactor shown in FIG. 5, when the operation coil (4) is demagnetized, the movable iron core (3) is separated from the fixed iron core (2) by a trip spring (not shown), and the crossbar (5)
Also occupies the upper part shown in the figure, and the fixed contact (8a) and the movable contact (6a) are separated, and an arc (12) occurs between the fixed contact (8a) and the movable contact (6a). As shown in Fig. 6, the metal arc extinguishing plate (13) is attracted to (12),
It is stretched like an arc (12a) and finally becomes an arc (12b), which is extinguished by the metal arc extinguishing plate (13) and the current is cut off.

[Problems to be solved by the invention]

The conventional power switch is configured and operates as described above, but the initial ignition position when both contacts (6a), (8a) are opened is the state of the surface of both contacts (6a), (8a). It was decided that it was decided depending on such things as. Therefore, as shown in FIG. 6, for example, the initial arc may occur at a position opposite to the arc drive side of the contacts (6a), (8a). In this case, the arc (12) causes the contacts (6a), ( 8a) After traveling on the arc (12a), the metal arc extinguishing plate (13) attracts the arc (12a).
The arc is extinguished in the state of b), and the arc (12) travels on the contacts (6a) and (8a), so that the contacts (6a) and (8a).
There was a problem that the consumption of water was large.

The present invention has been made to solve the above problems, and an object thereof is to obtain a power switch with less contact wear.

[Means for solving problems]

The power switch according to the present invention is configured such that at least one contact surface of the fixed and movable contacts is inclined so that both contacts come into contact only with the portion of the magnetic material close to the metal arc-extinguishing plate.

[Action]

In the power switch according to the present invention, since both contacts are in contact with each other at a position close to the arc driving side of the contact, the initial arcing position when the two contacts are opened is the arc driving side on the contact, and The contact time is short and the contact is prevented from being consumed due to the arc running on the contact.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

Since the power switch according to the embodiment of the present invention is similar to the conventional switch shown in FIG. 5, only its essential part is enlarged and shown in FIG. In this example, the movable contact (6b) is formed in a trapezoidal shape whose thickness increases toward the arc drive side (right side in FIG. 1), and the tips of the contacts (6a) and (8a) on the arc drive side are formed. Both contacts (6a) and (8a) are in contact only with parts (6b) and (8b).

Next, the operation will be described focusing mainly on the difference from the conventional one. When both contacts are opened, both contacts (6a) and (8a) are in contact with the arc drive side tips (6b) and (8b), and when both contacts (6a) and (8a) are opened, as shown in Fig. 2 As shown in Fig. 5, an arc (12) is generated at the arc drive side tips (6b) and (8b). This arc (12) is attracted to the magnetic metal arc extinguishing plate (13) and extinguished like an arc (12a).
As described above, in this embodiment, the arc (12) generated on the contacts (6a) and (8a) does not run on the contacts (6a) and (8a), but becomes an arc (12a) in a short time. Since it is extinguished, the contacts (6a) (8a) can be prevented from being consumed. In addition, since the contact (6a) can be thinly formed except for the tip portion (6b) on the arc drive side, expensive contact materials can be saved and the cost can be reduced.

Although the movable contact (6a) has a trapezoidal shape in the above embodiment, the fixed contact (8a) is shown in FIG.
May have a trapezoidal shape and, as shown in FIG. 4, when both contacts (6a) and (8a) are also trapezoidal, the same effect as in the above embodiment can be obtained. Also, the fourth
As shown in the figure, the tip of the contact on the arc drive side (6b),
(8b) may be formed into a curved surface, and in this case, the arc (12) can be prevented from sticking to the tip portions (6b) and (8b), and the arc can be extinguished more quickly.

Further, in the above embodiment, the case where the present invention is applied to the electromagnetic contactor which is a kind of power switch has been described, but the present invention can also be applied to other power switch such as wiring and disconnector. Needless to say.

〔The invention's effect〕

As described above, according to the present invention, at least one of the contact surfaces of the fixed and movable contacts is slanted so that both contacts come into contact with each other only at the portion of the magnetic material close to the metal arc-extinguishing plate. The stay time on the contact is short, which has the effect of reducing contact wear.

[Brief description of drawings]

FIG. 1 is a side view showing a main part of a power switch according to an embodiment of the present invention, FIG. 2 is an explanatory view for explaining an arc extinguishing action of the one shown in FIG. 1, FIG. 3 and FIG. FIG. 5 is an explanatory view illustrating an arc extinguishing action of a power switch according to another embodiment of the invention, FIG. 5 is a semi-front sectional view showing an example of a conventional power switch, and FIG. 6 is an arc extinguishing action of the one shown in FIG. It is an explanatory view explaining. In the figure, (6) is a movable contact, (6a) is a movable contact,
(6b) is the tip of the movable contact on the arc drive side, (8) is the fixed contact, (8a) is the fixed contact, (8b) is the tip of the fixed contact on the arc drive side, (12), (12a), ( 12b) is an arc,
(13) is a metal arc-extinguishing plate. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A fixed contact to which a fixed contact is joined, a movable contact to which a movable contact that can be brought into contact with and separated from the fixed contact is joined, and a magnetic metal disposed near a contact portion between the fixed contact and the movable contact. An arc extinguishing plate is provided, and at least one of the fixed contact and the movable contact is inclined so that the fixed contact and the movable contact come into contact with each other only at a portion of the magnetic body close to the metal arc extinguishing plate. An electric power switch characterized in that