JP2000231870A - Overcurrent tripping device for circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an overcurrent tripping device for a circuit breaker facilitating the assembly work of an armature and a return spring even in a very small space in a case. SOLUTION: This overcurrent tripping device for a circuit breaker is equipped with a heater assembly 11 comprising a heater 12, a fixed magnet 13, and a bimetallic strip, an armature 16 making turning motion opposite to the fixed magnet 13, and a return spring 18 engaging with both the armature and the magnet 13. The armature 16 is provided with a shaft part 16c around which a coil part 18a of the return spring 18 is mounted and a first spring catching part 16b for catching one leg 18b of the return spring 18, while the fixed magnet 13 is provided with a spring engagement part 13b engaging with the other leg 18c of the return spring 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermo-electromagnetic type overcurrent trip device incorporated in a circuit breaker for wiring or the like.

[0002]

2. Description of the Related Art FIG. 6 is an exploded perspective view showing a conventional overcurrent trip device of a circuit breaker disclosed in Japanese Utility Model Laid-Open No. 3-19236. In the figure, reference numeral 1 denotes a heater assembly, in which a U-shaped fixed magnet 3 and a bimetal 4 are integrally fixed to a heater 2 made of an L-shaped conductor by rivets 5. Reference numeral 6 denotes an armature, a pair of arms 6 formed on both sides so as to face the fixed magnet 3.
a is fitted into the receiving groove 7a of the case 7 of the circuit breaker, and is rotatably supported. Numeral 8 denotes a return spring 8, and both ends of the return spring 8 are hooked on a spring hook hole 6b formed in the armature 6 and a spring hook 3a formed on the fixed magnet 3, and the armature 6 is urged by the return spring 8. Thus, the lower end portion 6c is held at a fixed position in contact with the stopper 7c of the case 7. At this time, the armature 6 is urged by the return spring 8 so as not to come out of the receiving groove 7a. Further, the heater assembly 1 is fixed to the bottom of the case 7 from the back side of the case 7 with the mounting screw 9 at the L bent portion 2 a of the heater 2.

In such a conventional overcurrent tripping device for a circuit breaker, in order to mount the overcurrent tripping device on the case 7, first, the heater assembly 1 is fixed to the case 7 with mounting screws 9. And then armature 6 in case 7
After that, the return spring 8 is configured to be attached between the armature 6 and the heater assembly 1.

[0004]

In the conventional overcurrent tripping device for a circuit breaker as described above, a heater assembly 1 is provided.
After fixing the armature 6 and the return spring 8 to the case 7 in which the heater assembly 1 is assembled, the armature 6 and the return spring 8 must be sequentially assembled in a very narrow space. There was such a problem.

[0005] Further, in the inspection of a finished product after the completion of assembly as a circuit breaker, if the armature 6 and the return spring 8 must be removed in order to replace the return spring 8 due to defective characteristics or assembly error, etc. There is a risk that the return spring 8 may be pulled too much and a force greater than the stress may be applied to change the spring characteristics, making it difficult to replace the return spring 8.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a first object of the present invention is to fix an armature and a return spring in a narrow space of a case after fixing the heater assembly to the case. To obtain an overcurrent tripping device for a circuit breaker which can be easily assembled.

A second object of the present invention is to provide an overcurrent trip device for a circuit breaker in which the return spring can be easily replaced without changing the spring characteristics when the return spring needs to be replaced due to defective characteristics or assembly error. Is what you get.

[0008]

In an overcurrent trip device for a circuit breaker according to the present invention, a fixed magnet and a bimetal are integrally fixed to a heater made of a conductor, and the heater is fixed to a case of the circuit breaker. It has an assembly, a movable piece facing the fixed magnet, and a pair of arms. The arm is rotatably supported by the groove of the case, and is engaged between the armature and the fixed magnet. In an overcurrent trip device for a circuit breaker having a return spring, a shaft portion for inserting a coil portion of the return spring into the armature, and a first spring hook portion for hooking one foot of the return spring. And a spring engaging portion with which the other leg of the return spring is engaged with the fixed magnet.

Further, the armature is provided with a second spring hook portion to which the other leg of the return spring is temporarily hooked.

Further, a stopper is provided on the cover for covering the case to prevent the armature from falling out of the groove of the case.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a perspective view of an overcurrent trip device of a circuit breaker according to a first embodiment of the present invention, in which an essential part is cut away. FIG. 2 is an exploded perspective view of the overcurrent trip device of the circuit breaker shown in FIG. FIG. 3 is a longitudinal sectional view of a circuit breaker incorporating the overcurrent trip device shown in FIG.

In the drawings, reference numeral 10 denotes a case formed of a synthetic resin material, and a pair of grooves 10a to which a pair of arms 16c of the armature 16 described later is mounted (only one is shown in FIGS. 1 and 2). have. Reference numeral 11 denotes a heater assembly, and a fixed magnet 13 is provided on one side of the heater 12.
On the other side, a bimetal 14 is fixed with a rivet 15.

The heater 12 is formed by bending a conductor, and has a load-side terminal portion 12 a, a heater portion 12 b sandwiched between the fixed magnet 13 and the bimetal 14 to heat the bimetal 14, and a heater mounting portion 12 fixed to the case 10.
c. The fixed magnet 13 is formed of a magnetic material in a substantially U-shape, and has a pair of magnetic poles 13a facing an armature 16 described later and a return spring 1 described later.
And a spring engagement portion 13b with which the eight legs 18c engage. Reference numeral 14 denotes a plate-like thermal element, that is, a bimetal.

Reference numeral 16 denotes an armature, which includes a pair of movable pieces 16a facing the fixed magnet 13, and a pair of movable pieces 1a.
A first spring hook 16b protruding in a hook shape in a direction opposite to the fixed magnet 13 from a substantially lower end of the center 6a, and a pair of grooves 10a of the case 10 formed to protrude left and right above the movable piece 16a. A pair of arms 16 that are supported so as to be supported
and a shaft portion 1 formed continuously with one arm portion 16c and into which a coil portion 18a of a return spring 18 described later is inserted.
6d and an operation piece 16e extending upward from substantially the center of the pair of arms 16c and pressing a trip bar 25a described later during a trip operation.

Reference numeral 18 denotes a single torsion type torsion coil spring, that is, a return spring, which has a coil portion 18a wound tightly and a pair of feet 18a and 18b.
The armature 16 is engaged between the armature 16 and the fixed magnet 13, and normally urges the armature 16 in a direction in which the armature 16 is separated from the fixed magnet 13.

In FIG. 3, 19 is a cover for covering the case 10 made of synthetic resin, 20 is a power supply side terminal, 21 is a fixed contact fixed to the case 10, and 22 is a contact facing the fixed contact 21. It is a movable contact that separates. Reference numerals 23 and 24 denote flexible conductors and connection conductors for electrically connecting the movable contact 22 and the heater assembly 11. An opening / closing mechanism 25 has a trip bar 25a. 26 is a mounting screw.

A method of incorporating the overcurrent tripping device of the circuit breaker configured as described above into the case 10 will be described.
A description will be given based on FIG. 2 and FIG. First, the heater assembly 11 is inserted into the case 10, and the connection conductor 24 (shown in FIG. 3) is sandwiched between the heater mounting portion 12c and the case bottom surface 10b, and is fixed from the back side of the case 10 with the mounting screw 26.

Next, in order to incorporate the return spring 18 into the armature 16, the coil portion 18a of the return spring 18 is inserted into the shaft portion 16d of the armature 16, and one leg 18b of the return spring 18 is connected to the armature 16. It is hooked on one spring hook part 16b.

Next, in order to incorporate the armature 16 on which the return spring 18 is mounted into the case 10 on which the heater assembly 11 is mounted, the return arm inserted into the shaft portion 16d of the armature 16 is required. The other leg 1 of the spring 18
8c is held by hand and rotated in a counterclockwise direction, and the armature 16 is inserted into a pair of grooves 10a of the case 10.
Armature 1 up to a position where the pair of arms 16c
Insert 6. In this position, when the hand that holds down the other foot 18c of the return spring 18 is released, the other foot 18c rotates clockwise to engage with the spring engaging portion 13b of the fixed magnet 13, and the armature 16 and the armature 16 The installation of the return spring 18 is completed, and the assembly of the overcurrent trip device is completed. Then, the circuit breaker is completed by covering the cover 19.

In the circuit breaker constructed as described above, in FIG. 3, the overload current is applied to the power supply terminal 20 → the fixed contact 21 → the movable contact 22 → the flexible conductor 23 → the connection conductor 24 → the heater mounting. Plate → heater 12b → load side terminal 1
When flowing through the route 2a, the bimetal 14 is heated by the heat generated by the heater portion 12b, and the tip portion 14a of the bimetal 14 curves in the direction of arrow A as shown in FIG. Due to this bending, the trip bar 2 is formed at the tip portion 14a of the bimetal 14.
By pressing 5a, the switching mechanism 25 operates to trip the circuit breaker.

When a large current such as a short-circuit current flows through the heater section 12b, the fixed magnet 13 is magnetized,
The movable piece 16a of the armature 16 is instantaneously sucked into the armature 3a, and the operation piece 16e of the armature 16 is rotated clockwise. By this rotation, the operation piece 1 of the armature 16 is moved.
6e pushes the trip bar 25a to trip the circuit breaker in the same manner as described above, and performs a known breaking operation.

In the overcurrent tripping device for a circuit breaker constructed as described above, the armature 16 inserted at a predetermined mounting position has a pair of arm portions 16c having a return spring 1c.
8, it is urged by a downward force so as to be constantly pressed by the groove 10a of the case 10, so that the circuit breaker comes out of the groove 10a of the case 10 when the circuit breaker vibrates or the armature 16 rotates during the suction operation. Preventing.

When the armature 16 is removed from the case 10, the return spring 18 can be easily pulled out of the case 10 by simply pulling the armature 16 upward. When attaching the armature 16 to the case 10 again, the above-described armature 16
It can be easily installed in the same way as the method of assembling.

According to the structure of the first embodiment, when the overcurrent tripping device is incorporated in the case 10, the armature 16 and the return spring 18 are provided even in a very narrow space of the case 10 in which the heater assembly 11 is incorporated. Can be easily assembled. In addition, when inspecting the finished product of the circuit breaker, a characteristic failure or an assembly error may occur, and the return spring 1
When it is desired to replace the spring 8, there is no danger that the return spring 18 will be pulled too much and a force greater than the stress will be applied, thereby changing the spring characteristics. Therefore, the return spring 18 can be easily replaced and the instantaneous trip characteristic can be corrected in a short time. And the loss of assembly work time can be greatly improved.

Embodiment 2 FIG. 4 is a perspective view showing an armature portion of an overcurrent trip device of a circuit breaker according to Embodiment 2 of the present invention. In the figure, reference numeral 16f denotes a second spring hook portion formed so as to protrude from a surface of the armature 16 opposite to the first spring hook portion 16b, and can temporarily hook the other leg 18c of the return spring 18 temporarily. it can. The overcurrent trip device and the circuit breaker in which the armature 16 shown in FIG. 4 is incorporated are the same as those shown in FIGS. 1 and 3, and their illustration and description are omitted.

Case 10 to which heater assembly 11 is fixed
Inside the armature 16 and the return spring 18
In order to install the armature 16, the armature 16 assembled as shown in FIG.
6 to the position where the pair of arms 16c are fitted.

Next, the other foot 18c of the return spring 18 temporarily hooked to the second spring hook 16f of the armature 16 is pressed with the second spring hook 16 using a finger or a pin.
f, the other foot 18c of the return spring 18 automatically engages with the spring engaging portion 13a of the fixed magnet 13, and the movable piece 16a of the armature 16 is biased by the return spring 18 to stop the stopper 10c of the case 10. (Shown in FIG. 1) and is assembled at a predetermined mounting position.

According to the configuration of the second embodiment, the armature 16 is provided with the second spring hook 16f to which the other foot 18c of the return spring 18 is temporarily hooked, so that the armature 16 is inserted into the case 17. Before returning, the return spring 18 can be held by the armature 16, and as described in the first embodiment, there is no need to insert the return spring 18 into the groove 10a of the case 10 while holding the other foot 18c of the return spring 18 by hand. For example, when a return spring 18 having a strong spring load is required, it can be easily assembled.
Further, assembling workability is improved.

Embodiment 3 FIG. 5 is a perspective view showing an overcurrent trip device of a circuit breaker according to a third embodiment of the present invention, in which main parts are cut away. In the drawing, reference numeral 19a denotes a protrusion or a stopper provided to protrude inward from the side wall of the cover 19, and the armature 16c of the armature 16 inserted into the groove 13a of the case 10 is located at a position where the arm 16c does not come out upward. 16 is formed so as not to hinder the rotation.

In the first embodiment, the armature 16
Is received by the return spring 18 in a downward direction, and is rotatably supported in the groove 10 a of the case 7. Accordingly, the armature 16 is not moved by the groove 10 of the case 7 when the circuit breaker vibrates or the armature 16 rotates during the suction operation.
Although the armature 16 is prevented from falling out of the groove 10a, if the armature 16 is configured to be easily removed, if an upward force greater than the removal force acts on the armature 16, the armature 16 may fall out of the groove 10a. In particular, in the case of a circuit breaker for a low-rated current using a return spring 18 having a weak spring load, the possibility that the armature 16 comes out of the groove 10a is also increased.

According to the configuration of the third embodiment, when a large vibration applied to the circuit breaker or a large current such as a short-circuit current is cut off, the armature 16 is moved by the strong electromagnetic force acting on the armature 16. Groove 10
It is possible to prevent the armature 16 from rotating out of the position a, smoothly rotate the armature 16 during the suction operation, and obtain an overcurrent tripping device for a circuit breaker having stable overcurrent tripping characteristics.

[0032]

Since the present invention is configured as described above, it has the following effects.

A shaft portion for inserting the coil portion of the return spring into the armature and a first spring hook portion for hooking one leg of the return spring are provided, and the other leg of the return spring is engaged with the fixed magnet. When the armature is inserted into the case together with the return spring and the other leg of the return spring is released, the leg engages with the spring engaging portion of the fixed magnet. The work of assembling the armature and the return spring becomes easy even in a very small space. Also, when a defective characteristic or assembly error occurs during the inspection of the finished circuit breaker, and the return spring needs to be replaced, simply pull the armature upward and the return spring will come out of the fixed magnet's spring engaging part. Since the return spring can be easily removed, the return spring can be easily replaced without fear that the return spring is pulled too much and a force exceeding the stress is applied to change the spring characteristics.

Also, since the armature is provided with a second spring hook portion to which the other leg of the return spring is temporarily hooked,
The return spring can be held before the armature is assembled into the case, so that it is not necessary to hold the other leg of the return spring by hand while assembling the armature into the case, which further facilitates the assembling operation.

Further, a stopper for preventing the armature from slipping out of the groove of the case is provided on the cover for covering the case, so that a large vibration applied to the circuit breaker or a large current such as a short-circuit current can be cut off when the armature is cut off. The strong electromagnetic force acting prevents the armature from slipping out of the groove of the case.

[Brief description of the drawings]

FIG. 1 is a cutaway perspective view showing a main part of an overcurrent trip device of a circuit breaker according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the overcurrent trip device of the circuit breaker shown in FIG.

FIG. 3 is a vertical sectional view of a circuit breaker incorporating the overcurrent trip device shown in FIG.

FIG. 4 is a perspective view showing an armature portion of an overcurrent trip device of a circuit breaker according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing an overcurrent trip device of a circuit breaker according to a third embodiment of the present invention, in which main parts are cut away.

FIG. 6 is an exploded perspective view showing a conventional overcurrent trip device for a circuit breaker.

[Explanation of symbols]

10 case, 10a groove, 11 heater assembly, 1
2 heater, 12b heater portion, 13 fixed magnet, 13a spring engaging portion, bimetal, 16 armature, 16a movable piece, 16b first spring hook portion, 1
6d shaft portion, 16f second spring hook portion, 18 return spring, 18a coil portion, 18b, 18c foot, 1
9 Cover, 19a stopper.

Claims (3)

[Claims] 1. A heater assembly comprising a fixed magnet and a bimetal integrally fixed to a heater made of a conductor and fixed to a case of a circuit breaker, a movable piece facing the fixed magnet, and a pair of arms. An armature whose arm is rotatably supported in the groove of the case, and a return spring that is engaged between the armature and the fixed magnet. A shaft portion for inserting the coil portion of the return spring into the armature and a first spring hook portion for hooking one leg of the return spring are provided, and the other leg of the return spring is attached to the fixed magnet. An overcurrent trip device for a circuit breaker, comprising a spring engaging portion to be engaged. 2. The overcurrent trip device for a circuit breaker according to claim 1, wherein the armature is provided with a second spring hook portion to which the other leg of the return spring is temporarily hooked. 3. The overcurrent trip device for a circuit breaker according to claim 1, wherein a stopper for preventing the armature from coming out of the groove of the case is provided on a cover covering the case. .