JP3173635B2 - Earth leakage trip device for earth leakage 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 earth leakage trip device for an earth leakage circuit breaker, which receives a trip signal from an earth leakage detector, excites a trip coil, and drives a trip mechanism via an armature. In particular, the present invention relates to an earth leakage trip device used for a small earth leakage breaker having an overcurrent protection function using a bimetal.

[0002]

2. Description of the Related Art FIGS. 6 and 7 show a conventional structure of such an earth leakage trip device. FIG. 6 is a side view, and FIG. 7 is an exploded perspective view thereof. In these figures, a support yoke 1 also serving as a support member of the apparatus is made of an iron plate, and a trip coil 2 is gripped between legs 1a and 1b of the U-shaped portion forming a part of a magnetic circuit. I have. The trip coil 2 is formed by winding around a winding frame 3 having a cylindrical hole 3a at the center.
The fixed iron core 4 and the movable iron core 5 are inserted into a. Here, the fixed iron core 4 has a flange portion 4a having a diameter larger than that of the cylindrical hole 3a.
Is provided, and the fixed iron core 4 is fixed with the collar portion 4a sandwiched between the winding frame 3 and the leg portion 1b. On the other hand, the movable iron core 5 having a slightly smaller diameter than the cylindrical hole 3a is provided with a brim-shaped head 5b via a constricted portion 5a.
The movable core 5 is inserted into the cylindrical hole 3a so as to be movable in the axial direction, and the head 5b protrudes from a window hole 6 formed in the leg 1a.

On the other hand, a pair of left and right bearing pieces 1c is provided on the leg 1a.
The armature 7 of a resin molded product is rotatably supported on the bearing piece 1c. Here, a U-shaped bearing groove 8 is cut out in the left and right bearing pieces 1c, while a columnar shaft portion 7a is formed in the armature 7 so as to protrude left and right, and the armature 7 has the shaft portion 7a. It is fitted into the bearing groove 8 and is held so as not to fall off by a return spring 11 composed of a tension coil spring whose both ends are hooked to a latch 9 at one end and a through hole 10 of the leg 1b. A rectangular groove 7 is provided at the end of the armature 7 facing the movable iron core 5.
b is cut out from the side, and the constricted portion 5a is fitted into the rectangular groove 7b, whereby the head 5b of the movable iron core 5 is formed.
And the armature 7 is loosely engaged.

In such a leakage trip device, when the trip coil 2 is excited by a trip signal from a leakage detection unit (not shown), the movable core 5 is attracted to the fixed core 4 and the return spring 11 is accordingly moved. The armature 7 rotated in the direction of the arrow in FIG. 6 drives a tripping mechanism (not shown) to shut off the earth leakage breaker.

[0005]

In the conventional structure described above, the armature 7 has the shaft portion 7a fitted into the bearing groove 8, and
Although the return spring 11 prevents the return spring 11 from being removed, such an arrangement has good workability in assembling the armature 7, but the return spring 1 is used when the tripping device is incorporated into the earth leakage breaker body.
When 1 comes in contact with other parts and comes off, the armature 7 also comes off at the same time, so that there is a problem that nerves must be used for handling. SUMMARY OF THE INVENTION An object of the present invention is to provide an earth leakage trip device for an earth leakage breaker in which an armature and a return spring are prevented from coming off without impairing workability of assembling the armature.

In the conventional configuration, the head 5b of the movable iron core 5 that engages with the armature 7 is exposed, so that a bimetal used as an overcurrent protection element of an earth leakage breaker is arranged nearby. There is a possibility that the movable core head 5b comes into contact with this bimetal and the metal part of the earth leakage trip device is charged with the potential of the bimetal. Therefore, conventionally, in order to ensure insulation performance between the tripping coil 2 and the supporting yoke 1, it is necessary to strictly cover the outer periphery of the winding of the tripping coil 2 with an insulating tape, which causes a problem of increasing the cost. there were. Therefore, an object of the present invention is to provide an earth leakage trip device for an earth leakage breaker in which insulation between a movable iron core and a bimetal is achieved.

On the other hand, the performance of the earth leakage breaker is normally guaranteed in the operating temperature range of -10 to 40.degree. C. When used at a temperature extremely lower than this temperature range (for example, -30.degree. May not operate normally, and abnormalities may occur in operation characteristics such as an increase in operation sensitivity current value or an increase in operation time. Therefore, if the use environment can be prevented from turning on the earth leakage breaker in such a situation,
Safe state is preferred. In view of the above, the present invention provides an earth leakage trip device in which insulation between a movable core and a bimetal is performed, wherein when an earth leakage breaker is placed in a cryogenic environment, the earth leakage trip is automatically blocked. It is intended to provide a device.

[0008]

According to the present invention, there is provided a plate material having a U-shaped portion forming a part of a magnetic circuit, and a pair of left and right bearing pieces bent at one leg of the U-shaped portion. And a armature made of an insulator rotatably supported on a bearing piece of the support yoke via a shaft formed to project right and left, and a bobbin having a cylindrical hole at the center. A trip coil wound and held by the U-shaped portion of the supporting yoke, and a fixing inserted into the cylindrical hole of the bobbin and fixed to the other leg of the U-shaped portion of the supporting yoke. An iron core, which is inserted movably in the axial direction into the through-hole of the bobbin facing the fixed iron core, through a window hole formed in the one leg of the U-shaped portion of the support yoke. A movable core having a protruding head engaged with the armature and holding the movable core separated from the fixed core; In order to prevent the armature and the return spring from coming off, the armature is attached to both of the pair of bearing pieces bent and formed in the U-shaped part of the supporting yoke in order to prevent the armature and the return spring from coming off. While providing a circular bearing hole to support the shaft portion of each, while making the thickness of one bent portion of these bearing pieces thinner than the other,
This bearing piece is deformed by a thin bent portion, and the armature is assembled between the bearing pieces, and the return spring is constituted by a compression coil spring. It shall be inserted between the fixed iron core and the movable iron core.

The present invention also provides an overcurrent protection element located near the armature at an engagement portion of the armature with the head of the armature in order to insulate the armature from the bimetal. An insulating wall covering the head of the movable core is provided for the bimetal. Furthermore, in this case, in order to automatically prevent the earth leakage circuit breaker from being turned on in a cryogenic environment, the armature is tripped with a bimetal that is curved backward in a cryogenic environment, and the armature is held in an operating position.

[0010]

In the present invention, the bearing hole of the bearing yoke for supporting the shaft portion of the armature is formed in a circular shape, while the bent portion of the bearing piece is inserted into the bearing hole to insert the shaft portion. Is made thinner than the other, so that the bearing piece can be easily deformed at the thin bent portion. With this, one of the armature shaft portions is inserted into the bearing hole of the other bearing piece with the bending angle of the thinner bearing piece set to an obtuse angle, and then the two bearing pieces are sandwiched by pliers, etc. The armature can be easily assembled by inserting the other shaft into the bearing hole while deforming the bearing piece into a right angle bending state, and the armature does not come off because the shaft is restrained in the bearing hole . At the same time, the return spring, which no longer needs to hold the armature, is used as a compression coil spring, which is removed and inserted between the fixed iron core and the movable iron core in the cylindrical hole of the coil bobbin. Is also gone.

Further, in the present invention, an insulating wall for covering the movable iron core head is provided at an engagement portion of the armature with the movable iron core head with respect to a bimetal positioned near the armature, and the bimetal is an armature. Should not come into direct contact with the armature head when approaching. This eliminates the risk that the metal part of the earth leakage breaker will be charged with the potential of the bimetal via the movable iron core. In such a case, if the armature is reversely bent at a very low temperature and the armature is tripped and held in the operating direction by utilizing the reverse bending characteristic of the bimetal in a very low temperature environment, if the state is extremely low, The opening / closing mechanism cannot be reset, and the closing of the earth leakage breaker can be prevented.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Here, FIG. 1 is a side view of an earth leakage breaker showing a cutaway main part and showing the inside, FIG. 2 (A) is a plan view of the earth leakage trip device in FIG. 1, (B) is a side view, FIG. (A) is a plan view of the supporting yoke in FIG. 2, (B) is a side view, (C) is a front view, (A) of FIG. 4 is a top view of the armature in FIG. 2, and (B) is a side view. FIG. 5C is a bottom view, and FIG. 5 is a plan view showing how the armature of FIG. 3 is assembled to the support yoke of FIG. Note that the same reference numerals are used for the portions corresponding to the conventional example.

First, in FIG. 3, a supporting yoke 1 integrally formed in an illustrated shape by pressing from an iron plate is a leg 1a.
And an L-shaped support leg 1d is provided in the U-shaped portion having the U and 1b, and a screw hole for fastening to the main case of the earth leakage breaker is provided in the L bent portion of the support leg 1d. I have. A pair of left and right bearing pieces 1c for holding the armature 7 are formed on one of the legs 1a of the U-shaped part for gripping the trip coil 2 (FIG. 2), and these bearing pieces 1c have circular bearings. A hole 12 is coaxial. here,
One of the bearing pieces 1c (upper side of (A) in FIG. 3 and right side of (C)) has a thickness of about 70% that of the other bent part (see FIG. 3 (A)), and also has a lateral width. It is narrowed so as to be constricted from the left and right (see FIG. 3C), so that deformation at this portion is facilitated. Before the armature 7 is assembled, the thin side ear side 1c has a bending angle Θ, as shown in FIG.
Is kept at an obtuse angle of about 120 degrees. FIG. 3 (C)
As shown in FIG. 2, the movable iron core 5 (FIG. 2 (B))
A circular window hole 6 through which the air flows.

On the other hand, the armature 7 shown in FIG. 4 is formed of resin into the illustrated shape, and a shaft portion 7a supported in the bearing hole 12 of the bearing piece 1c is formed to protrude right and left. A trapezoidal column-shaped recess 13 is provided at a portion of the movable iron core 5 where the head 5b (see FIG. 2 (B)) engages. A slit 14 for passing the constricted portion 5a of the movable core 5 is provided.

Next, in FIG. 2, the configurations of the trip coil 2 and the fixed core 4 are substantially the same as those in the conventional configuration of FIGS. 6 and 7, and the fixed core 4 is inserted into the cylindrical hole 3a of the bobbin 3. The trip coil 2 thus obtained is gripped between the legs 1a and 1b of the U-shaped portion of the support yoke 1 shown in FIG.
The movable core 5 is also substantially the same as the conventional configuration, except that a small-diameter cylindrical protrusion 11c for positioning the return spring 11 is provided on the end face facing the fixed iron core 4. In this case, the return spring 11 is formed of a compression coil spring, and the outer diameter thereof is slightly smaller than the inner diameter of the cylindrical hole 3 a of the bobbin 3.

Here, the armature 7 is connected to the support yoke 1 as shown in the figure.
After the return spring 11 is inserted into the cylindrical hole 3a, the flanged head 5b of the movable iron core 5 is fitted into the recess 13 of the armature 7 as shown in FIG. 1c, the movable iron core 5 is inserted into the cylindrical hole 3a, and then one shaft portion 7a of the armature 7 is inserted into the bearing hole 12 of the bearing piece 1c in a right angle bending state. In this state, a force is applied by straddling the pliers between the two bearing pieces 1c to deform the thin-side bearing piece 1c in the direction of the arrow in FIG. The part 7a is inserted into the bearing hole 12 of the bearing piece 1c.

FIG. 1 shows a state in which the earth leakage trip device thus assembled is installed in the earth leakage breaker main body. As described above, the earth leakage trip device is supported by the support yoke 1. The armature 7, which is fastened to the main body case 15 via the leg 1 d and receives the force of the return spring 11 via the movable iron core 5, has a wall 7 c on the upper surface side of the concave portion 13.
6, the position is regulated to the illustrated posture. The bimetal 16 is provided as an overcurrent protection element. The bimetal 16 overlaps the movable contact 17 at the L-bent base and is fastened to the main body case 15 by a screw (not shown).
The fixed contact 18 opposed to the movable contact 17 is not shown, but a power supply terminal is integrally formed on the right end side in the figure, and the load contact terminal is integrally formed on the movable contact 17 on the left end side in the figure. The current-carrying conductor is connected, and between the load-side terminal and the movable contact 17, a leakage detection unit 19, which is partially shown, surrounding the current-carrying conductor is arranged.

FIG. 1 shows an open state of the earth leakage breaker. When the earth leakage detecting unit 19 detects a ground fault in the closed state and the trip coil 2 is excited by the trip signal, the movable core Numeral 5 is attracted by the fixed iron core 4 and moves rightward in the figure to rotate the armature 7 counterclockwise about the shaft portion 7a. The armature 7 pushes the trip bar 20 via the operation piece 20a, and tilts the trip bar 20 counterclockwise about the shaft portion 20b as a fulcrum. As a result, the opening / closing mechanism (not shown) is operated, and the movable contact 17 is separated as shown in the figure. When the current supplied to the movable contact 17 becomes an overcurrent state, the bimetal 16 which is heated by the Joule heat and bent leftward is adjusted by the adjusting screw 21.
Then, the trip bar 20 is tilted down, and the opening / closing mechanism is operated to separate the movable contact 17. The bimetal 16 also reversely curves in the direction of the arrow in an extremely low temperature environment of, for example, -10 ° C. or lower, rotates the armature 7 counterclockwise through the wall 7c, and keeps the trip bar 20 down. as a result,
In such a cryogenic state, the switching mechanism cannot be reset, and the closing of the earth leakage breaker is prevented.

In the earth leakage trip device described above, the bearing hole 12 for supporting the shaft portion 7a of the armature 7 has a circular shape.
Since the armature a is completely restrained, the armature 7 does not come off, and the return spring 11 is also housed in the winding frame 3 so that it does not come off. Therefore, unlike the conventional configuration shown in FIGS. 6 and 7, the return spring 11 does not come off by touching other parts when it is incorporated in the earth leakage breaker main body, and the armature 7 does not come off accordingly.

In the recess 13 of the armature 7 with which the head 5b of the movable core 5 engages, a wall 7c is provided between itself and the bimetal 16, so that the movable core 5 and the bimetal 16 are completely insulated. . Therefore, as in the conventional configuration shown in FIGS. 6 and 7, the bimetal 16 serving as the charging unit comes into contact with the movable core 5, and the metal unit (the supporting yoke 1 and the fixed iron core 4) of the earth leakage trip device is connected to the charging unit. There is no danger. In this case, since the bimetal 16 has the reverse bending characteristic, the armature 7 is tripped through the wall 7c and held in the operative state in the cryogenic environment as described above, so that when the earth leakage breaker is placed in such an environment. Is prevented from being introduced.

[0021]

According to the present invention, since the armature and the return spring do not easily come off, there is no need to use nerves when assembling the earth leakage trip device into the earth leakage circuit breaker main body, and the assembly work is eliminated. Efficiency goes up. Also, since the movable iron core is insulated from the adjacent bimetal by the insulating wall of the armature, there is no danger that the supporting yoke of the earth leakage trip device becomes a charged part, and therefore, the insulation of the outer periphery of the trip coil is simplified and the cost is reduced. Down can be planned. Also, in this case, the armature can be tripped and maintained in the operating state by utilizing the reverse bending characteristics of the bimetal at cryogenic temperatures, so in a cryogenic environment, the closing of the earth leakage breaker is automatically blocked, The malfunction can be prevented.

[Brief description of the drawings]

FIG. 1 is a side view showing the inside of a ground fault circuit breaker according to an embodiment of the present invention, with a part broken away.

FIG. 2 shows the earth leakage trip device in FIG.
(A) is a plan view and (B) is a side view.

3A and 3B show the supporting yoke in FIG. 2, wherein FIG. 3A is a plan view, FIG. 3B is a side view, and FIG. 3C is a front view.

4A and 4B show the armature in FIG. 2, wherein FIG. 4A is a top view, FIG. 4B is a side view, and FIG. 4C is a bottom view.

FIG. 5 is a plan view showing how the armature of FIG. 4 is assembled to the support yoke of FIG. 3;

FIG. 6 is a side view showing a conventional earth leakage trip device.

FIG. 7 is an exploded perspective view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support yoke 1a Leg 1b Leg 1c Bearing piece 2 Tripping coil 3 Reel 3a Cylindrical hole 4 Fixed iron core 5 Movable iron core 6 Window hole 7 Armature 7a Shaft 7c Insulation wall 11 Return spring 12 Bearing hole 16 Bimetal

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01H 83/02 H01H 71/12 H01H 73/36

Claims (3)

(57) [Claims] 1. A support yoke made of a plate material having a U-shaped part forming a part of a magnetic circuit and having a pair of left and right bearing pieces bent on one leg of the U-shaped part. An armature made of an insulator rotatably supported by a bearing piece of the support yoke via a shaft formed to protrude from the support yoke; And a fixed core inserted into the cylindrical hole of the bobbin and fixed in contact with the other leg of the U-shaped portion of the support yoke, and facing the fixed core. The head is inserted movably in the axial direction into the through hole of the bobbin, and projects through a window hole formed in the one leg of the U-shaped portion of the support yoke and engages with the armature. It comprises a combined movable core and a return spring for holding the movable core separated from the fixed core. In a leakage breaker for an electric circuit breaker, a circular bearing hole for supporting a shaft portion of an armature is provided on each of a pair of bearing pieces bent and formed in a U-shaped portion of a supporting yoke, and these bearing pieces are provided. The thickness of one of the bent portions is made thinner than the other, the bearing piece is deformed at the thin bent portion, the armature is assembled between the bearing pieces, and the return spring is a compression coil spring. An earth leakage trip device for an earth leakage breaker, wherein said return spring is tripped and inserted between a fixed iron core and a movable iron core in a cylindrical hole of a coil bobbin. 2. A yoke having a U-shaped portion forming a part of a magnetic circuit, and a support yoke made of a plate material having a pair of left and right bearing pieces bent on one leg of the U-shaped portion. An armature made of an insulator rotatably supported by a bearing piece of the support yoke via a shaft formed to protrude from the support yoke; A tripping coil gripped by the U-shaped portion, a fixed core inserted into the through hole of the bobbin and fixed in contact with the other leg of the U-shaped portion of the support yoke, and facing the fixed core. The head is inserted movably in the axial direction into the through hole of the bobbin, and projects through a window hole formed in the one leg of the U-shaped portion of the support yoke and engages with the armature. It comprises a combined movable core and a return spring for holding the movable core separated from the fixed core. In the earth leakage trip device for an electric circuit breaker, an insulating wall that covers the movable core head with respect to a bimetal of an overcurrent protection element located near the armature at an engagement portion of the armature with the movable core head. An earth leakage trip device for an earth leakage breaker, comprising: 3. The earth leakage trip device for an earth leakage breaker according to claim 2, wherein the armature is tripped and held in an operating posture by a bimetal bent in an extremely low temperature environment.