JPS6367304B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic relay having a function of protecting against abnormal current.

Figure 1 shows the structure of a conventional self-holding electromagnetic relay. In the figure, 31 is a base, 32 is a coil, 33 is a coil frame, 34 is a plunger,
35 is a yoke, 36 is a permanent magnet, 37 is a magnetic plate,
38 is an actuator, 39 is a return coil spring,
40 is a contact spring, 41 is a movable contact, 42 is a contact,
Reference numeral 43 indicates a terminal, and reference numeral 44 indicates a cover, whose operation is such that when a voltage is applied to the coil 32, the plunger 34 operates, and accordingly, the contact spring 40 is operated, so that the contacts 41 and 42 are turned on. Even when the coil 32 is de-energized, the plunger 34 is held by the magnetic flux of the permanent magnet 36 and continues to be in the on state. To turn off contacts 41 and 42,
When a voltage in the opposite direction to that during operation is applied to the coil 32, the plunger 34 returns to its original position, and the contacts 41 and 42 are turned off.

However, in such an electromagnetic relay, if an abnormal current such as an overcurrent or short circuit current flows through the contacts 41 and 42, the contacts 41 and 42 may become welded, or the cord, load equipment, or relay itself may be damaged or burnt out. If there is a risk of
There were problems with economic efficiency and safety, such as repair of the wiring system.

Attempts have also been made to install breakers to prevent these accidents, but the breakers are not appropriate or there is no breaker that can coordinate with the electromagnetic relay, resulting in insufficient protection.

The present invention has been proposed in view of the above points, and its purpose is to reliably detect abnormal current flowing in an electric circuit, return the plunger, and promptly open the contact. By doing so, it is an object of the present invention to provide an electromagnetic relay having an abnormal current protection function that protects electric circuits, load equipment, and the relay itself from damage, burnout, etc.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 2 and 3 show an embodiment of the electromagnetic relay according to the present invention. In the figures, 1 is a hollow coil frame having flanges 1a and 1b, and a substantially central portion on the outer periphery of the coil frame 1 is shown. A coil 2 is wound between flanges 1a and 1b extending from the top to the top, and a slidable plunger 3 is disposed within the hollow portion of the coil frame 1. Reference numeral 4 denotes a yoke provided at the upper end of the flange 1a side of the coil frame 1 in the illustrated state, and a permanent magnet 5 is disposed in contact with the upper surface of the yoke 4, and an L-shaped yoke is disposed on the upper surface of the permanent magnet 5. The inner surfaces of the bent portions 6a of No. 6 are arranged in contact with each other. A part of the coil 2 is positioned opposite to the inner surface of the other bent portion 6b of the yoke 6, and a yoke 7 having a substantially U-shaped cross section is located at the end of the bent portion 6b. The proximal end is fixed.
The yoke 7 has a bent portion 7a and a bent portion 7b opposite to the bent portion 7a, and the lower portion of the cylindrical coil frame 1 extends through the bent portion 7a. Further, a hole 7b' is also formed in the bent portion 7b, and this hole 7b' is formed in the bent portion 7b.
A part of the plunger 3 protrudes through b', and an actuator 8 is connected to the lower end of the plunger 3. A slit 8a is formed in the actuator 8, and a terminal plate 9 is provided in the slit 8a. A contact spring 12 having a movable contact 11 at its tip that can come into contact with and separate from the fixed contact 10 is inserted, and the plunger 3
The contacts are turned on and off as the machine moves.

Therefore, the coil frame 1 is inside the U-shaped yoke 7.
An overcurrent detection coil 13 is wound through the yoke 7 and the overcurrent detection coil 13, and a type of overcurrent detection sensor is constituted by the yoke 7 and the overcurrent detection coil 13. And coil 1
One end 13a of the coil 13 is electrically connected to a substantially L-shaped terminal plate 15 fixed on the upper surface of the base 14, and the other end 13b of the coil 13 has its base end connected to the contact spring 12 fixed on the base 14. It is connected.

Note that X in the figure represents a cover that is placed over the base 14.

Next, the operation of the present invention will be explained.

Now, as shown in FIG. 2, the plunger 3 is attracted to and held by the yoke 4 side by the magnetic force of the permanent magnet 5, etc., and the contact spring 12 is held in the upper position by the actuator 8 that interlocks with the plunger 3, so that the contact point is In the case of closed terminal board 1
5. If an abnormal current such as an overcurrent or short circuit current flows in the electrical circuit including the overcurrent detection coil 13, contacts 11, 10, terminal plate 9, etc., the overcurrent detection coil 1
A large current flows through the plunger 3 and the yoke 7, and at this time the magnetic flux passing through the plunger 3 and the yoke 7 increases, causing the plunger 3 and the yoke 7 to
A suction force is generated in the gap B between the two. When the suction force increases due to the holding force in the gap A between the upper end of the plunger 3 and the yoke 4, the plunger 3 is sucked downward and returned to its original position, as shown in FIG. The contact 11 is separated from the fixed contact 10, and the electric path is interrupted.

As described above, according to the present invention, an overcurrent detection coil is inserted into the electrical circuit, and the magnetic flux generated when an abnormal current flows is used to forcefully drive the plunger that drives the contact spring provided in the electromagnetic relay body. Since it is driven to restore the power, the occurrence of an abnormal current can be quickly detected and the electrical circuit can be quickly cut off, thereby reliably protecting the cord and load equipment, thereby improving safety. In addition, since the present invention also has a breaker function, there is no need to provide a separate breaker, which is economical, and there is no need to worry about coordinating with such a breaker. have

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional self-holding electromagnetic relay, FIG. 2 is a sectional view showing an embodiment of the electromagnetic relay according to the present invention, and FIG. 3 is an explanatory diagram of the same operation. 1... Coil frame, 2... Coil, 3... Plunger, 4... Yoke, 5... Permanent magnet, 6, 7...
... Yoke, 8 ... Actuator, 9, 15 ...
Terminal board, 10... Fixed contact, 11... Movable contact,
12...Contact spring, 13...Overcurrent detection coil,
14...Base.

Claims (1)

[Claims] 1 A contact is provided between the input and output terminal plates, and a coil is provided to attract and drive the plunger, and a permanent magnet is arranged opposite to the plunger and attracts and holds the plunger, and the plunger is attracted and driven to the permanent magnet side. In an electromagnetic relay that closes the contact when An electromagnetic relay characterized in that when an abnormal current flows, the plunger is driven in a direction opposite to the permanent magnet to open the contact point through the overcurrent detection coil.