JP2861446B2 - Electromagnetic trip device for circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic trip device for detecting an overcurrent state of an electric circuit in a circuit breaker such as a wiring circuit breaker or an earth leakage circuit breaker and performing a breaking operation of the circuit breaker.

[0002]

2. Description of the Related Art FIGS. 7 and 8 show a general structure of the above-mentioned conventional electromagnetic trip device. FIG. 7 is a longitudinal sectional view of a main part (load side) of a circuit breaker in which the electromagnetic trip device is incorporated. FIG. 8 and FIG. 8 are side views of the electromagnetic trip device during operation.
The electromagnetic trip device includes a fixed yoke 2 having a U-shaped cross section, which is arranged around a conductor 1 serving as a current path, an armature 3 facing the fixed yoke 2, a return spring 4 for urging the armature 3, a bimetal 5, and the like. ing.

[0003] The bimetal 5 and the fixed yoke 2 are superimposed on the conductor 1 from front and rear, and are integrally connected by the conductor 1 and rivets 6. The armature 3 has a rotating shaft 3a integrally formed on the left and right, which is fitted into a U groove 8 of a case 7 of a circuit breaker, and is rotatably supported. Return spring 4
Is bridged between the fixed yoke 2 and the armature 3. The armature 3 is rotated from the return spring 4 to the rotating shaft 3.
The lower end 3b abuts against a stopper 9 formed in the case 7 by receiving a clockwise force shown in FIG.
Is maintained. The conductor 1 has a base bent in an L shape and is overlapped with the connection plate 10, and a screw 11.
To the case 7. The connection plate 10 is electrically connected to a movable contact (not shown). The upper end of the conductor 1 is connected to the terminal plate 12 on the load side.

[0004] In this configuration, when flowing through the conductor 1 is large overcurrent, the attraction force acting between the fixed yoke 2 and the armature 3, the armature 3 against the return spring 4 as shown in FIG. 8 It is instantaneously sucked by the fixed yoke 2 and rotates counterclockwise. The armature 3 hits the trip crossbar 13 at the upper end 3c and turns it counterclockwise against the return spring 14 (FIG. 7 ). As a result, the lock of the opening / closing mechanism is released, and the movable contact is released. When the circuit breaker is interrupted, electromagnetic attraction force because the current is interrupted conductors 1 disappears, the armature 3 is returned to the state of FIG. 7 by the force of the return spring 4. In addition,
When an overload current of about 10 times the rated current flows, the bimetal 5 which is heated and bent by the Joule heat generated by the conductor 1 rotates the trip crossbar 13 via the adjusting screw 5a at the upper end, Similarly, the movable contact is separated.

FIG. 9 shows the relationship between the stroke and the suction force of the armature 3 in the above-described suction process and the load force generated by the return spring 4 and the like. The suction force increases sharply as the armature 3 approaches the fixed yoke 2. The load force gradually increases as the return spring 4 is pulled and extended, and increases instantaneously when the armature 3 hits the trip crossbar 13. Thereafter, it increases with the extension of the two return springs 4 and 14, but decreases rapidly when the locking of the opening / closing mechanism is released, and thereafter gradually increases until only the suction is completed due to only the load force from the armature 3.

In order for the armature 3 to be sucked by the fixed yoke 2, the suction force must exceed the load force. Thus, in FIG. 9, when the suction of the armature 3 starts from _a point S is susceptible aspiration, when starting with S ₂ points is impossible aspiration. That is, the variation ΔL of the gap L between the armature 3 and the fixed yoke 2
The presence or absence of suction changes whether suction is possible. From this, it is understood that the accuracy of the gap L greatly affects the operation characteristics of the electromagnetic trip device.

[0007]

In the conventional structure shown in FIG. 7, the fixed yoke 2 and the armature 3 are separately supported by the case 7, and the return spring 4 is stretched between them. Therefore, these components must be stored separately from each other until the electromagnetic trip device is incorporated into the circuit breaker, and management and handling are complicated. Further, since the armature 3 is incorporated into the case 7 separately from the fixed yoke 2, the fixed yoke 2 and the armature 3
It is difficult to determine the positional relationship between Therefore, the gap L between them greatly varies, and the return spring 3
It takes a lot of man-hours to adjust the operating characteristics, such as replacing the data and correcting the variation. Accordingly, an object of the present invention is to solve these problems and to provide an electromagnetic trip device for a circuit breaker that is easy to manage and has stable operation characteristics.

[0008]

In order to achieve the above object, according to the present invention, a support member is attached to a fixed yoke, the armature is rotatably supported by the support member, and the armature and the support member are connected to each other. A return spring shall be installed between the two. In this case, a rotating shaft is integrally formed on both sides of the armature, a bearing hole for supporting one of the rotating shafts is provided on one side wall of the support member, and the other of the rotating shafts is supported on the other side wall. A bearing groove is provided, and a return spring is mounted so as to be offset to the bearing groove side, and a stopper is provided for abutting the armature on a side wall of the support member on the side provided with the bearing hole.
Armature support stabilizes against vibration and shock when opening and closing the circuit breaker. Further, by providing the armature stopper on the opposite side of the return spring with respect to the rotation axis of the armature, the turning operation of the armature becomes smooth.

[0009]

A support member is attached to the fixed yoke, the armature is rotatably supported by the support member, and a return spring is mounted between the armature and the support member to combine these components to form a unit. This makes it possible to store the components in a state where they have been formed, which facilitates the management and handling of the components. Also, by allowing the armature to be supported by the support member integrated with the fixed yoke,
Compared with the conventional configuration in which a mold resin case is interposed between the fixed yoke and the armature, the positional accuracy between the two is significantly improved, and the gap variation is reduced.

By the way, when a rotating shaft is integrally formed on both sides of the armature and the rotating shaft is supported by bearings of a support member, if the bearings are formed with holes on both the left and right sides, a support is required for assembling the armature to the support member. The member has to be pushed out, which causes a problem in workability. Therefore, this problem can be solved if one of the bearings is a hole and the other is a partially cut-out groove, but as a result, the rotation shaft on the bearing groove side is caused by vibration or impact when opening and closing the circuit breaker. There is a risk that the armature will come off and come off the stopper.

As a solution to this problem, by mounting the return spring with the bias toward the bearing groove side, the action of the return spring pressing the rotating shaft against the bottom of the bearing groove is enhanced,
The lifting of the rotating shaft is effectively prevented. Furthermore, by providing the stopper on the side wall of the support member on the side where the bearing hole is provided, even if the rotating shaft rises, the lower end of the armature that comes into contact with the stopper hardly floats, so there is a concern that the armature may come off from the stopper. Not at all. Also, by providing a stopper on the opposite side of the return spring across the rotating shaft of the armature, the direction of the returning spring force acting on the rotating shaft and the direction of the suction force match,
The position of the rotating shaft in the bearing that supports the rotating shaft is stabilized, and the influence of play between the rotating shaft and the bearing is eliminated.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Note that the same reference numerals are used for the portions corresponding to the conventional example. Here, FIG. 1 is a side view of the electromagnetic trip device in a non-operating state, FIG. 2 is a side view of a main part during the operation, FIG. 3 is an exploded perspective view of an armature and a support member, and FIG.
Is an enlarged view showing a method of forming the rotating shaft of the armature,
FIG. 5 is a side view for explaining the lifting of the rotating shaft, and FIG. 6 is a front view thereof as viewed from the direction of arrow VI.

1 to 3, a fixed yoke 2 and a bimetal 5 are superposed on a conductor 1 with the conductor 1 interposed therebetween, and these are integrally connected by a rivet 6. The fixed yoke 2 is bent in a U-shape on both left and right sides surrounding the conductor 1 except for a joint 2 a with the conductor 1. A U-shaped support member 15 made of a plate material is superimposed on the outside of the fixed yoke 2, and is fixed vertically by rivets 16. The armature 3 is rotatably supported by the support member 15, and is supported by a bearing groove 17 on a side wall on the near side of the support member 15 and a bearing hole 18 (FIG. 3) on the opposite side wall.
The rotation is performed by supporting a rotating shaft 3 a integrally formed on both sides of the armature 3. The return spring 4 is mounted between the support member 15 and the armature 3 , one end of which is supported by the hook hole 19 of the upper end 3c of the armature 3 and the other end is supported immediately below the armature 3 , as shown in FIG. By being hooked on the hook holes 20 at the upper edge of the member 15, it is biased toward the bearing groove 17.

A stopper 9 is formed integrally with the side wall of the support member 15 on the side where the bearing hole 18 is provided, on the side opposite to the return spring 4 with the rotating shaft 3a of the armature 3 therebetween.
The armature 3 which receives a force in the counterclockwise direction in FIG. 1 from the return spring 4 has a lower end 3 b abutting against a stopper 9, and a gap L is held between the armature 3 and the fixed yoke 2. The armature 3 is punched out of a plate and then bent to form the illustrated shape. The rotating shaft 3a has a prismatic shape immediately after the punching, as shown by a two-dot chain line in FIG. Therefore, the sheet is compressed from both sides by a split forming punch 21 as shown in the figure, and is formed into a cylindrical shape.

As in the conventional example, a terminal plate 12 on the load side of the circuit breaker is connected to the upper end of the conductor 1 by spot welding, and the base bent L is overlapped with a connecting plate (not shown) leading to the movable contact. And screwed into the circuit breaker case. A trip crossbar 13 is located in front of the armature 3 and the bimetal 5, and the trip crossbar 13 has a pawl 13a engaged with a latch member (not shown) to lock the opening / closing mechanism of the circuit breaker. A return spring 14 urges the trip crossbar 13 counterclockwise in the drawing.

In such an electromagnetic trip device, when the current flowing through the conductor 1 is overloaded, the bimetal 5 heated by the Joule heat of the conductor 1 is largely bent rightward in FIG. , The trip crossbar 13 is pushed, and is rotated clockwise in the figure. Thereby, the above-mentioned engagement of the claw 13a is released, the locking of the opening / closing mechanism is released, and the movable contact is released. When a large overcurrent such as a short-circuit current flows through the conductor 1, the lower end 3b of the armature 3 is attracted to the fixed yoke 2 against the return spring 4, and as shown in FIG. Hit the bar 13. Thus, the movable contact is similarly separated.

In the above configuration, the armature 3 is supported by the support member 15 integral with the fixed yoke 2 via the rotating shaft 3a, and the return spring 4 is mounted between the armature 3 and the support member 15. Therefore, these parts including the conductor 1 and the terminal plate 12 can be stored in a unitized state by the electromagnetic tripping device alone.
Parts management and handling are easy. Also, fixed yoke 2
Since the armature is supported by the supporting member 15 integrated with the armature 3, the armature 3 is separated from the fixed yoke 2 by the case 7.
The positional accuracy between the two is higher and the variation in the gap L is smaller than in the configuration incorporated in the first embodiment.

Further, one of the bearings for supporting the rotating shaft 3a of the armature 3 is a bearing groove 17. Therefore, when assembling the armature 3 to the support member 15, after inserting the rotation shaft 3 a into the bearing hole 18, the opposite rotation shaft 3 a may be fitted into the bearing groove 17.
There is no need to spread the gap between the side walls. However, due to the vibration or shock generated when the circuit breaker is opened and closed, the rotating shaft 3a is moved to the bearing groove 1.
There is a danger of floating within 7 as shown in FIGS. This lift is large, and the rotating shaft 3a is
7 or the lower end 3b of the armature 3 comes off the stopper 9, the electromagnetic trip device becomes inoperable.

On the other hand, in the illustrated configuration, the return spring 4 is mounted so as to be offset to the bearing groove 17 side. For example, when the return spring 4 is mounted at the center of the support member 15 in the width direction. The return spring 4 which presses the rotating shaft 3a against the bottom of the bearing groove 17 has a stronger spring action, and the floating shaft 3a is less lifted. Moreover, even if rotation shaft 3a floats in the bearing groove 17, the lower end portion 3 b of the armature 3 hardly float the bearing hole 18 side as seen from FIG. 6, the support stopper 9 on the side of the bearing hole 18 In the illustrated configuration formed on the side wall of the member 15, there is no fear that the armature 3 comes off the stopper 9. In order to prevent the armature 3 from coming off the stopper 9, the height H (FIG. 5) of the stopper 9 may be increased. However, doing so causes a problem that the stopper 9 is elongated and the strength is reduced. Occurs.
In the illustrated configuration, even if the dimension H is small, it does not come off, which is advantageous in strength.

In the illustrated construction, the stopper 9 of the armature 3 is formed on the opposite side to the return spring 4 with the rotation shaft 3a interposed therebetween, so that the spring force of the return spring 4 acting on the rotation shaft 3a is fixed. The direction of the suction force of the yoke 2 coincides with the left direction in FIG. 1, and the rotating shaft 3 a pressed by the return spring 4 against the left wall of the bearing groove 17 and the bearing hole 18 in the drawing is also used during suction. Rotation starts at the same position. Therefore, even if there is play between the rotating shaft 3a and the bearing groove 17 or the bearing hole 18, the positional displacement of the rotating shaft 3a does not occur, which is coupled with the fact that the rotating shaft 3a is press-formed in a cylindrical shape. The operation becomes smooth.

[0021]

According to the present invention, since the armature is supported by the support member integral with the fixed yoke, the electromagnetic trip device can be unitized outside the circuit breaker, so that the management and handling of parts becomes easy, and The positional accuracy of the relationship between the fixed yoke and the armature is improved, and variations in operating characteristics are reduced. Further, when one of the bearings of the support member for supporting the rotating shaft of the armature is a groove and the other is a hole, the return spring is mounted so as to be offset to the bearing groove side, and the armature stopper is provided on the bearing hole side. By
There is no need to worry about the armature floating and coming off the stopper. Further, by providing the armature stopper on the side opposite to the return spring across the rotation axis of the armature, the armature operation becomes smooth and the operation characteristics are stabilized.

[Brief description of the drawings]

FIG. 1 is a side view of an inactive state of an electromagnetic trip device according to an embodiment of the present invention.

FIG. 2 is a side view of a main part of the electromagnetic trip device of FIG. 1 during operation.

FIG. 3 is an exploded perspective view of a support member and an armature in FIG. 1;

FIG. 4 is an enlarged view showing a method of forming the armature rotating shaft in FIG.

FIG. 5 is a side view of the electromagnetic trip device for explaining the lifting of the armature.

FIG. 6 is a front view as seen from the direction of arrow VI in FIG. 5;

FIG. 7 is a longitudinal sectional view of a main part of a circuit breaker for showing a conventional example.

8 is a side view of the electromagnetic trip device in FIG. 7 during operation.

FIG. 9 is a diagram showing general load characteristics of an electromagnetic trip device.

[Explanation of symbols]

 2 Fixed yoke 3 Armature 3a Rotating shaft 4 Return spring 9 Stopper 15 Support member 17 Bearing groove 18 Bearing hole

Claims (3)

(57) [Claims] A fixed yoke disposed surrounding a current path of a circuit breaker, an armature rotatably supported opposite the fixed yoke, and the fixed yoke contacting the armature with a stopper. An electromagnetic trip device for a circuit breaker having a return spring for holding a gap between the armature and the armature. An electromagnetic trip device for a circuit breaker, comprising a return spring mounted between the support member and the support member. 2. A rotary shaft is integrally formed on both sides of the armature, a bearing hole for supporting one of the rotary shafts is provided on one side wall of the support member, and the other of the rotary shafts is formed on the other side wall. In addition to providing a bearing groove to be supported, a return spring is mounted so as to be offset to the bearing groove side, and a stopper is provided for abutting the armature on a side wall of the support member on the side where the bearing hole is provided. 2. The electromagnetic trip device for a circuit breaker according to claim 1, wherein: 3. The electromagnetic trip device for a circuit breaker according to claim 1, wherein the armature stopper is provided on the opposite side of the return spring with respect to the rotating shaft of the armature.