JPH04253135A - Electromagnetic trip device for circuit breaker - Google Patents

Abstract

PURPOSE:To miniaturize a coil by reducing the load on the coil which attracts an armature. CONSTITUTION:A return spring 21 is inserted between the tip of the armature 18 of an electromagnetic trip device 13 and a circuit breaker main body case 1, and the spring action of the return spring 21 is reversed to the same direction from the opposite direction to the electromagnetic attracting force in the process that the armature 18 is attracted to an armature 17 by the electromagnetic attracting force of a coil 16. The coil 16 is reversely aided by the return spring 21 during attraction, and its load is reduced.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is an electromagnetic actuator that detects overload current, short circuit current (hereinafter collectively referred to as overcurrent), etc. in molded circuit breakers, earth leakage circuit breakers, etc. and trips the circuit breaker. The present invention relates to an electromagnetic tripping device, and more particularly to an electromagnetic tripping device that reduces the load on an electromagnet that attracts an armature.

0002

2. Description of the Related Art FIG. 8 is a vertical sectional view of a conventional circuit breaker in an ON state. In the figure, 1 is a main body case made of molded resin, 2 is a fixed contact that also serves as a terminal board on the power supply side, 3 is a movable contact that comes into contact with this, and 4 is a pin 5 that holds the movable contact 3. A holder 6 is an operating handle 8 rotatably supported on the main body case 1 via a shaft 7.
1 is a link connecting the holder 4 and the operating handle 6 via pins 9 and 10, 11 is a trip bar that locks the end 4a of the holder 4, and 12 is a link that is stretched between the holder 4 and the operating handle 6. 13 is an electromagnetic tripping device. Note that the trip bar 11 is biased counterclockwise in the figure by a torsion spring (not shown).

The electromagnetic trip device 13 has a coil 16 wound around the outside of a cylinder 15 fixed to an L-shaped yoke 14.
The structure is such that an armature 18 is rotatably supported by a yoke 14, facing an armature 17 that closes the head of the cylinder 15. One end of the coil 16 is connected to the movable contactor 3 via a lead wire 19, and the other end is connected to a terminal plate 20 on the load side. The armature 18 is urged away from the armature 17 by a return spring 21 provided between the armature 18 and the yoke 14 . Although not shown, a plunger is housed in the cylinder 15 together with a return spring.
Furthermore, silicone oil is sealed.

In such a configuration, since the pin 10 is on the right side of the shaft 7 in the ON state shown in the figure, the opening/closing spring 12
The operating handle 6, which receives a rotational force in the clockwise direction in the figure, is about to push down the holder 4 via the link 8. As a result, the movable contact 3 is pressed against the fixed contact 2, and the end 4a of the holder 4 is pressed against the claw 1 of the trip bar 11.
The illustrated state is maintained by being pressed against 1a. Here, when the operating handle 6 is rotated to the OFF position indicated by the two-dot chain line in the figure, the pin 10 moves to the left side of the shaft 7, so the holder 4 is lifted via the link 8 and the movable contact 3 is opened. do.

Furthermore, when an overcurrent flows through the coil 16, the armature 18 is attracted to the armature 17 against the return spring 21 due to the electromagnetic attraction force generated by the coil 16, and its operation end 18a engages the lever portion of the trip bar 11. 11b and rotate it clockwise as shown in the figure. Therefore, holder 4
The end portion 4a comes off the claw 11a and falls into the recess 11c. As a result, the operating handle 6 is opened by the spring force of the opening/closing spring 12.
It is rotated to the FF position and the movable contact 3 is opened. Thereafter, when the coil 16 is de-energized, the trip bar 11 returns to the state shown in the drawing due to the action of a torsion spring (not shown).

[0006]

[Problems to be Solved by the Invention] In the conventional electromagnetic tripping device 13, the return spring 21 always acts in the opposite direction to the electromagnetic attraction force, so the coil 16 needs to generate an extra force corresponding to that amount. . As the electromagnetic attraction force increases, the number of turns of the coil 16 increases, resulting in a larger external shape, and also increases resistance, which increases heat generation. Furthermore, since the electromagnetic attractive force has less remaining power, the tripping operation becomes unstable. An object of the present invention is to provide an electromagnetic tripping device for a circuit breaker in which the return spring of the armature acts in the same direction as the electromagnetic attractive force, thereby reducing the size of the coil and improving the tripping characteristics. It is something.

Incidentally, a circuit breaker may have a built-in alarm switch (usually a microswitch) that sends out a trip signal indicating that an electromagnetic tripping device has operated. In that case, operating the alarm switch directly with the armature of the electromagnetic tripping device increases the load on the coil, so the control lever of the alarm switch is linked to a part of the tripping mechanism that is conventionally unlocked by being struck by the armature. That's what I was doing. However, in such a conventional configuration, since another mechanism is interposed between the armature and the actuator of the alarm switch, there is a large variation in the actuator operation stroke due to errors in component dimensions.
Adjusting the mounting position of the alarm switch took time and there were problems with operational reliability. SUMMARY OF THE INVENTION An object of the present invention is to provide an electromagnetic tripping device for a circuit breaker that can improve the operational reliability of an alarm switch.

[0008]

[Means for Solving the Problems] The present invention is configured such that the spring force of the return spring acting on the armature is reversed from the opposite direction to the same direction as the electromagnetic attraction force in the process of attracting the armature. To achieve the above purpose. The return spring can be inserted between the tip of the armature and the main body case of the circuit breaker. Further, in this invention, the actuator of the alarm switch is operated at the same time as the tripping mechanism at the operation end of the armature where the spring force of the return spring is reversed during the suction process.

[0009]

[Operation] In the conventional configuration, the return spring always acts in the opposite direction to the electromagnetic attraction force, so its spring load increases as the attraction progresses, but in this invention, the spring force of the return spring acts electromagnetically in the process of attraction of the armature. Since the return spring is reversed in the same direction as the attraction force, the return spring will then contribute to the electromagnetic attraction force, and the load on the coil will be reduced accordingly. Also,
Since the spring force of the return spring is reversed in the process of armature suction, surplus operating force is created for the armature, making it possible to operate the actuator of the alarm switch with the armature at the same time as the tripping mechanism.

0010

[Example] Example 1 Figures 1 and 2 are longitudinal sectional views of Example 1 of the present invention.
is in the ON state, and FIG. 2 shows the moment when the armature of the electromagnetic tripping device is attracted. Note that the same reference numerals are used for parts corresponding to those in the conventional example. 1, the difference from the conventional example is that the return spring 21 of the armature 18 is composed of a compression coil spring, and this return spring 21 is inserted between the tip of the armature 18 and the main body case 1. . Further, a pin 10 connecting the operating handle 6 and the link 8 is provided near the operating end 18a of the armature 18.
A reset piece 18b is integrally formed so as to face. Here, as shown in FIG. 2, when the electromagnetic tripping device 13 operates and the armature 18 is attracted to the armature 17,
At the next moment, the movable contactor 3 opens and separates as described in the conventional example, and the operating handle 6 rotates to the OFF position. Changes in the force relationship of the return spring 21 with respect to the armature 18 during this time will be explained with reference to FIG.

FIG. 3 shows the main parts of the armature 18 and the armature 1.
7 is shown enlarged. In the figure, when the electromagnetic tripping device 13 is in the inoperative state, the spring force F acting on the armature 18 from the return spring 21 passes through the right side of the rotation fulcrum 22 of the armature 18 in the figure, and the armature 18 is connected to the armature 17. Distance between suction surfaces G after being pulled away from
is maintained. Here, armature 18 is armature 1
7, the armature 18 rotates clockwise in the figure.
A line 24 connecting the center of and the center of the mounting surface 23 of the return spring 21
The action of the spring force F is reversed and the armature 18
will rotate in the same direction as the electromagnetic attraction force.

FIG. 5 shows the relationship between the electromagnetic attraction force of the coil 16 and the applied load during the attraction process of the armature 18, in which (A) shows the case of the embodiment, and (B) shows the case of the conventional example. In FIG. 5(B), the load applied by the return spring 21 gradually increases with the suction of the armature 18, and the end 18a of the armature 18 is connected to the lever part 11 of the trip bar 11.
When it hits b, the force increases rapidly to a level that exceeds the electromagnetic attraction force. Here, the applied loads at that point are a trip bar load that overcomes the friction with the holder 4 and rotates the trip bar 11, and a torsion spring load that deforms the torsion spring attached to the trip bar 11. It consists of and,
Before long, the end 4a of the holder 4 is in the recess 1 of the trip bar 11.
1c, the applied load becomes only the applied load of the return spring 21 and the torsion spring.

On the other hand, in the case of the embodiment shown in FIG. 5(A), at the point when the action of the spring force F of the return spring 18 is reversed, the applied load becomes negative and starts to add to the electromagnetic attractive force. . When the operating end 18a of the armature 18 hits the trip bar 11, the load increases rapidly, but it is smaller than in the conventional example by the negative load of the return spring 21. That is, in the embodiment, the return spring 2 is released before the armature 18 hits the trip bar 11.
1 is reversed, and the trip bar 11 can be rotated with a smaller electromagnetic attraction force than before.

Returning to FIG. 2 again, when the armature 18 is attracted to the armature 17, the reset piece 18b approaches the pin 10. Subsequently, the movable contact 3 opens and separates, but the operating handle 6 is returned to the OFF position indicated by the two-dot chain line. At this time, the pin 10 collides with the reset piece 18b, causing the armature 18 to move counterclockwise. Rotate. As a result, the action of the spring force F of the return spring 21 is reversed again, and the armature 18 is reset to the state shown in FIG. 1 in preparation for the next tripping operation. Note that in the state of FIG. 1 where the armature 18 is not attracted, the reset piece 18b is connected to the pin 1.
Located at a position far from 0, the ON/OFF of the operating handle 6
It does not interfere with F operation.

Embodiment 2 FIG. 4 is an enlarged view of main parts showing Embodiment 2 of the present invention. In this case, a leaf spring is used as the return spring 21, and is inserted between the tip of the armature 18 and the main body case 1, as in the case of FIG. A spring force F is generated by the elastic force of the curved abdomen 21a. Its operation is the same as that in FIG. 1, and its explanation will be omitted.

As described above, according to the configurations of the first and second embodiments, the spring force F of the return spring 21 is reversed in the direction of adding to the electromagnetic attraction force during the attraction process of the armature 18. The return spring 21
Coil 16 compared to the conventional configuration where the load increases due to
load is much smaller. Also, armature 18
By integrally forming a reset piece 18b that contacts the operating handle 6, the armature 18 after the tripping operation is
will now be restored automatically.

Embodiment 3 Next, FIGS. 6 and 7 show Embodiment 3 in which the circuit breaker of Embodiment 1 has a built-in alarm switch for detecting tripping operation. FIG. 6 shows the ON state, and FIG. are longitudinal cross-sectional views at the moment when the armature is attracted. In Figure 6,
25 is an alarm switch consisting of a microswitch fixed to the main body case 1; 26 is a reset button slidably held in the main body case 1; one end of the reset button 26 engages with the actuator 25a of the alarm switch 25; The end is peeking out from the main body case 1. On the other hand, the operating end 18a of the armature 18 extends further than in the case of FIG. 1, and the tip reaches near the actuator 25a. However, in this case, the reset piece 18b is not provided.

Here, when an overcurrent flows and the armature 18 is attracted to the armature 17 as shown in FIG. 7, the armature 18 rotates the trip bar 11 with the operating end 18a to turn off the circuit breaker. However, at the same time, the actuator 25a is rotated clockwise at the tip of the operating end 18a, and the push button 25b of the alarm switch 25 is pushed in to switch its contact. As a result, a trip operation signal is sent to the outside. Further, along with this, the reset button 26 is pushed by the actuator 25a and protrudes from the main body case 1 as shown in the figure, indicating that a trip operation has been performed.

Once the armature 18 is attracted,
As already mentioned, the state shown in FIG. 7 is maintained due to the reversal of the return spring 21. Even if an attempt is made to turn on the circuit breaker in this state, the claw 11a of the trip bar 11 escapes from the end 4a of the holder 4, so the circuit breaker cannot be turned on. Therefore, when the reset button 26 protruding from the main body case 1 is pushed in, the armature 18 is reset via the armature 25a.
is rotated counterclockwise, and when the return spring 21 is reversed, it automatically returns to the state shown in FIG. This also resets the trip bar 11, allowing the circuit breaker to turn on. Note that the reset button 26 is held in a pressed state by the actuator 25a.

According to the configuration of the third embodiment, the alarm switch 25 and the reset button 26 are activated by the armature 18, which is operated by the return spring 21 whose spring force is reversed during the suction process.
By configuring the configuration to operate the reset button 26,
The trip state is maintained unless the armature 18 is reset by pushing in, and the trip operation can be easily seen from outside the circuit breaker, and the circuit breaker will not be turned on inadvertently without removing the cause of the trip operation. Improves safety.

[0021]Furthermore, conventionally, as a mechanism for operating an alarm switch, a mechanism is known in which an actuator is linked with a part of a tripping mechanism that is unlocked by being struck by an armature of an electromagnetic tripping device. In such a mechanism, the operating stroke changes due to variations in the dimensions of the parts interposed between the armature and the actuator, which poses a problem in operational reliability. In contrast, in the configuration shown, the armature 18
Since the actuator 25a directly acts on the actuator 25a, the operation is reliable, and the alarm signal can be easily output from any circuit breaker regardless of the structure of the tripping mechanism.

[0022]

[Effects of the Invention] According to the present invention, the return spring, which conventionally obstructed armature suction, acts to assist the electromagnetic suction force from the middle of suction, so the coil is smaller than the conventional one. , the external dimensions of the circuit breaker are also reduced. In addition, the coil generates less heat, resulting in a lower temperature rise, and since there is more margin in the tripping force, the reliability of the circuit breaker is improved, including improved tripping characteristics. Furthermore,
Since the actuator of the alarm switch can be directly operated using the operating force of the armature with surplus power, the alarm signal can be easily and reliably extracted.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a circuit breaker in an ON state showing a first embodiment of the present invention.

2 is a longitudinal sectional view of the armature of the circuit breaker of FIG. 1 at the moment when it is attracted; FIG.

FIG. 3 is an enlarged view of the main part of FIG. 1;

FIG. 4 is an enlarged view of main parts of Example 2 of the present invention.

FIG. 5 is a diagram showing the relationship between the electromagnetic attraction force of the coil, the applied load, and the distance between attraction surfaces, in which (A) is the case of the embodiment of the present invention, and (B) is the case of the conventional example.

FIG. 6 is a vertical cross-sectional view of a circuit breaker in an ON state showing a third embodiment of the present invention.

7 is a longitudinal sectional view of the armature of the circuit breaker of FIG. 6 at the moment when it is attracted; FIG.

FIG. 8 is a vertical cross-sectional view of a conventional circuit breaker in an ON state.

[Explanation of symbols]

1 Main body case 12 Electromagnetic tripping device 17 Armature 17b Reset piece 20 Return spring 25 Alarm switch

Claims (3)

[Claims] [Claim 1] In an electromagnetic tripping device for a circuit breaker that trips the circuit breaker by attracting the armature against the return spring by electromagnetic attractive force when an overcurrent flows, the action of the return spring of the armature is as follows. An electromagnetic tripping device for a circuit breaker, characterized in that the armature is configured to reverse from the opposite direction to the same direction as the electromagnetic attraction force in the process of being attracted. 2. An electromagnetic tripping device for a circuit breaker according to claim 1, wherein a return spring is inserted between the tip of the armature and the main body case of the circuit breaker. 3. An electromagnetic tripping device for a circuit breaker according to claim 1 or 2, wherein the actuator of the alarm switch for extracting the trip signal to the outside is directly operated by the armature. .