KR20130044319A - Circuit breaker - Google Patents

Abstract

It is an object of the present invention to provide a circuit breaker capable of suitably moving an arc between contacts to the arc dissipation device side even in a relatively small current region without enlarging the device. A pair of front and rear fixed contacts 2 and 3 disposed to face each other, a movable contact 4 interposing the fixed contacts 2 and 3, and side surfaces of both ends of the movable contact 4 are disposed therebetween. A pair of front and rear magnetic drive yokes 10 made of permanent magnets are provided on each pole. In the closed electrode state, the movable contactor 4 is pressed against the fixed contactors 2 and 3 by the contact springs 5 to close each pole conduction path, and in the open state, the movable contactor 4 contacts with the opening and closing mechanism. It presses against the spring 5, and opens the said conduction path by opening from the fixed contact 2,3.

Description

Circuit breaker {CIRCUIT BREAKER}

TECHNICAL FIELD The present invention relates to a circuit breaker used for wiring protection and the like, and more particularly to a circuit breaker having a linear two-contact structure.

As a conventional circuit breaker, there exists a technique of patent document 1, for example. In this technique, a U-shaped magnetic body is provided outside the movable contact and the fixed contact having different current paths. By such a configuration, when a large current such as a short-circuit current flows, an electromagnetic repulsive force (Lorentz force) in the direction of repulsion between the contacts can be generated, and the movable contact is operated in the direction of opening from the fixed contact. Can improve the blocking performance. Moreover, the arc which generate | occur | produces between contacts after a contact opening can be moved to the arc extinguishing apparatus arrange | positioned at the both ends of a movable contact.

Patent Document 1: Japanese Patent No. 3859053

However, the electromagnetic force generated by the magnetic material is proportional to the current. Therefore, in the conventional circuit breaker, a large electromagnetic force cannot be generated in a relatively small current region of about the rated current.

Therefore, in the low current region, the force for moving the arc generated at the contact opening to the arc extinguishing device is insufficient. For this reason, the arcs generated between the contacts at the time of current interruption (contact opening operation) must be interrupted at a short distance between both contacts, and in order to cope with the high voltage in a DC circuit having no current zero, more contacts are required. Requires opening distance. As a result, there is a problem that the arc extinguishing device and the product are enlarged.

Therefore, an object of the present invention is to provide a circuit breaker capable of appropriately moving an arc between contacts to the arc dissipation device side even in a relatively small current region without enlarging the device.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, the 1st aspect of the circuit breaker which concerns on this invention is a direct-and-a pair pair of front and back fixed contactors arrange | positioned so as to oppose each other, and the linear type which entangles the said fixed contactors. Each pole has a movable contactor and a pair of front and rear magnetic drive yokes arranged at both ends of both sides of the movable contactor, respectively, and the movable contactor is pressed against the fixed contactor by a contact spring. The movable contact is closed against the contact spring by an opening / closing mechanism, and is opened so as to open the conduction path by opening from the fixed contact. The magnetic drive yoke is a permanent magnet. It is characterized by consisting of.

Accordingly, when a current flows in the movable contact in the closed state, the current is linked with the magnetic flux focused by the magnetic drive yoke, and the movable contact receives a strong electromagnetic repulsive force (Lorentz force) and is driven in the direction of opening from the fixed contact. In the contact opening operation, an arc is generated between the fixed contact point and the movable contact point, but the arc is driven by linking with the magnetic flux strengthened by the magnetic drive yoke to the arc extinguishing device disposed before and after the movable contact point. Move and disappear.

Here, since a permanent magnet is used as the magnetic drive yoke, it is possible to have a constant magnetic flux regardless of the magnitude of the current. Therefore, even in a relatively small current region, the arc generated between the contacts in the contact opening operation can be efficiently driven by the arc extinction device.

The second aspect of the present invention is characterized in that the magnetic drive yoke is made of a U-shaped permanent magnet, and is disposed such that both side portions of the movable contact face each other.

Thus, since the magnetic drive yoke is constituted by the U-shaped permanent magnet, the U-shaped both legs can reliably sandwich the side portions of both ends of the movable contact, so that the magnetic drive yoke can be disposed at a desired position. Because of this, the degree of freedom of placement is large.

Further, a third aspect is disposed below the movable contact so as to span between the pair of arc dissipating devices disposed before and after the movable contact, and between these arc dissipating devices, and at the time of breaking the current, the fixed contact and the movable part. An arc current plate for current flow of the foot on the movable contact side of the arc generated between the contacts, wherein the arc current plate has a pair of U-shaped magnetic bodies formed by bending on the movable contact side; The magnetic drive yoke is made of a rectangular permanent magnet, and the bottom surface thereof is fixed to the upper surface of both legs of the U-shaped magnetic body, so that the side surfaces of the movable contact are disposed so as to be interposed therebetween.

As described above, since the magnetic drive yoke is made of a rectangular permanent magnet, the size of the permanent magnet can be reduced as compared with the case of forming a U-shaped permanent magnet. Therefore, the cost can be reduced by that much. Moreover, since it is comprised integrally with an arc current board, the number of component parts can be reduced and the assembly property of a circuit breaker can be simplified.

In addition, a fourth aspect is arranged so as to span a pair of arc dissipation devices arranged in front and behind the movable contactor and these arc dissipation devices, and to generate an arc generated between the fixed contactor and the movable contactor when the current is interrupted. An arc current plate configured to cause a current on the side of the movable contact side of the arc; the arc current plate has a pair of U-shaped magnetic bodies that are bent and formed on the movable contact side, and the magnetic drive yoke And a rectangular permanent magnet, and being fixed to the inner surfaces of both leg portions of the U-shaped magnetic body, so as to sandwich the side portions of the movable contact.

As described above, since the rectangular permanent magnet is fixed to the inner surface of both legs of the U-shaped magnetic body formed by bending the arc current plate, the permanent magnet is fixed to the tip of both legs of the U-shaped magnetic body. The leakage magnetic flux can be reduced. As a result, the arc generated between the contacts in the contact opening operation can be efficiently driven to the arc extinguishing device.

According to the present invention, since the permanent magnet is used as the magnetic drive yoke, even in a relatively small current region, the arc generated around the energization path at the time of contact opening can be reliably moved to the arc dissipation device side. Therefore, since it can contribute to the provision of the small circuit breaker suitable for a DC circuit, and the miniaturization of the main body of a product, and to share components with AC exclusive products more, a low cost circuit breaker can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the structure of the current interruption | blocking part of the circuit breaker which concerns on embodiment of this invention.
FIG. 2 is an exploded perspective view showing the structure of the magnetic drive yoke portion of the first embodiment. FIG.
3 is a cross-sectional view showing the structure of the current interruption unit at the contact closed pole position.
4 is a vector diagram of a sectional view near the contact of the first embodiment and of a current, a magnetic flux, and an electron repelling force.
Fig. 5 is a vector diagram of a plan view near the contact and current, magnetic flux, and electron repelling force of the first embodiment.
It is a figure which shows the structure of the current interruption part, and the advancing direction of an arc in the contact opening position of 1st Embodiment.
FIG. 7 is a cross-sectional view showing the structure of the current interruption unit in the second embodiment. FIG.
8 is an exploded perspective view showing the structure of the magnetic drive yoke portion of the second embodiment.
Fig. 9 is a vector diagram of a plan view near the contact and current, magnetic flux, and electron repelling force of the second embodiment.
FIG. 10 is an exploded perspective view showing the structure of the magnetic drive yoke portion of the third embodiment. FIG.
Fig. 11 is a vector diagram of a plan view near the contact and current, magnetic flux, and electron repelling force of the third embodiment.
12 is a diagram showing the leakage magnetic flux from the magnetic drive yoke.
Fig. 13 is a diagram showing the structure of a current interruption unit of a conventional circuit breaker.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing.

(First embodiment)

(Configuration)

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the current interruption part of the circuit breaker which concerns on embodiment of this invention. Here, the circuit breaker which concerns on this embodiment is a circuit breaker which has a linear 2-contact structure.

In the figure, reference numeral 1 denotes a current interruption unit. U-shaped stationary contacts 2 and 3 made of flat conductors are disposed to face each other in the phase conduction paths, and fixed contacts 2a and 3a are attached to each phase conducting path. The rectangular movable contactor 4 bent in a truncated shape at both ends has a pair of movable contacts 4a and 4b that can be in contact with the fixed contacts 2a and 3a, respectively. In the closed pole state in which the energizing path is closed, this movable contactor 4 is urged toward the fixed contactors 2 and 3 by a contact spring 5 made of a compression spring, and the movable contacts 4a and 4b are fixed contacts ( In contact with 2a and 3a, respectively, the contact between the fixed contacts 2 and 3 is entangled. On the other hand, in the open state shown in the drawing of opening the conduction path, the movable contactor 4 is pushed down against the contact spring 5 by an opening / closing mechanism (not shown), so that it is opened from the fixed contactors 2 and 3. do.

Moreover, a pair of arc extinction apparatus 6 is arrange | positioned at the front and back of the movable contactor 4, The several sheets of grid 7 surround the both ends of the movable contactor 4. As shown in FIG. The grid 7 consists of a U-shaped magnetic plate in plan view, and is supported by the side walls 8 of a pair of left and right insulators. Further, an arc current plate 9 made of a high resistance material such as a steel sheet is provided below the arc quenching device 6 so as to span the arc quenching device 6 before and after. It also functions as a support plate for the contact spring 5.

In the figure, reference numeral 10 denotes a pair of front and rear magnetic drive yokes made of a U-shaped permanent magnet. The magnetic drive yoke 10 is disposed so as to sandwich the side portions at both ends of the movable contact 4 at the left and right leg portions. Moreover, one leg part is a S pole and the other leg part is an N pole among the left and right leg parts, and is arrange | positioned so that it may become the polarity shown in FIG. The left and right leg portions of the magnetic drive yoke 10 are covered with the insulating cover 11.

FIG. 2 is an exploded perspective view showing the structure of the magnetic drive yoke portion including the arc current plate 9, the magnetic drive yoke 10, and the insulating cover 11.

The insulating cover 11 is formed in a U shape having a pair of left and right sidewalls 11a and 11b by resin molding, and the movable contact 4 is opened and closed between the sidewalls 11a and 11b (Fig. 1). Up and down) to be movable. The sidewalls 11a and 11b of the insulating cover 11 are formed with a bag-shaped portion with a lower surface open, respectively. These bag-shaped portions are covered by both leg portions 10a and 10b of the magnetic drive yoke 10 when the circuit breaker is assembled. In the case of assembling the circuit breaker, the arc current plate 9 is disposed between the both legs 10a and 10b of the magnetic drive yoke 10 and outside the lower surface of the insulating cover 11.

(action)

Next, the operation of the first embodiment will be described with reference to FIGS. 3 to 6.

3 is a cross-sectional view showing the structure of the current interrupting portion at the contact closed pole position, FIG. 4 is a sectional view near the contact point, FIG. 5 is a plan view near the contact point, and FIG. It is a figure which shows a progress direction.

In the closed-pole state shown in FIG. 3, as shown by the arrow in the figure, it is assumed that a large current I, such as a short circuit current, flows. At this time, as shown in FIG. 4, if the current I is flowing so that the movable contactor 4 faces from the top to the bottom in the vertical direction of the sheet of FIG. 4, the magnetic flux Φ based on the current I is The magnetic drive yoke 10 is focused and passes through the movable contact 4 and the magnetic drive yoke 10 clockwise. At that time, the magnetic flux? Passing through the movable contactor 4 from the left to the right in FIG. 4 is orthogonal to the current I flowing through the movable contactor 4. Therefore, according to the left-hand rule of Fleming, the movable contactor 4 As shown in FIG. 4, the electron repelling force (Lorentz force) F1 acts downward.

At the same time, an overcurrent detection device (not shown) detects the overcurrent and outputs a tripping signal, which receives and opens and closes the movable contactor 4 in the downward direction in FIG. As a result, the fixed contacts 2a and 3a of the fixed contacts 2 and 3 and the movable contacts 4a and 4b of the movable contact 4 are separated.

Therefore, the movable contact 4 is driven by opening at a speed greater than that of driving the electromagnetic repulsive force alone or the opening / closing mechanism alone. Therefore, the breaking performance can be improved by that much.

In the contact opening operation in which the fixed contacts 2a and 3a and the movable contacts 4a and 4b are separated, an arc is generated between the fixed contacts 2 and 3 and the movable contact 4. As this arc A is orthogonal to the magnetic flux (magnetic flux passing from the left to the right in FIG. 4) Φ strengthened by the magnetic drive yoke 10, as shown in FIG. 5, the arc of Fleming's left-hand law A force F2 acting on A toward the outside in the front-back direction of the movable contact 4 acts. As a result, the arc A generated between the contacts is directed to the arc A1-> arc A2-> arc A3-> arc A4 and the arc extinguishing device 6 side which is arrange | positioned outside the front-back direction of the movable contact 4, as shown in FIG. Move. The arc A drawn into the arc extinguishing device 6 is analyzed, cooled, extinguished, and the short-circuit blocking operation is completed.

At that time, since the arc current plate 9 is provided, the foot on the movable contact 4 side of the arc A is moved to the arc current plate 9, and the arc A does not allow current to flow through the movable contact 4. It disappears in the state, and damage to the movable contact 4 by a large electric current is suppressed.

By the way, conventionally, a magnetic body is used as a magnetic drive yoke.

Fig. 13 is a diagram showing the structure of a current breaker of the conventional circuit breaker, (a) is a plan view of the current breaker, and (b) is a front view of the current breaker. Here, the example which formed the magnetic drive yoke 110 which consists of a magnetic body integrally with the arc current board 109 is shown. That is, the pair of front and rear magnetic drive yokes 110 are integrally bent and formed in the arc current plate 109, and stand and extend in the opening movement direction of the movable contact 104.

With such a configuration, when a large current such as a short circuit current flows, as in the present embodiment, an electromagnetic force in the direction of repulsion between the contacts can be generated, and the movable contact 104 can be operated in the direction of opening from the fixed contact. Moreover, after contact opening, the electromagnetic force which moves the arc which generate | occur | produces between a contact to an arc extinction apparatus can be generated.

However, since the electromagnetic force generated by the magnetic body is proportional to the current, when the magnetic body is used as the magnetic drive yoke, a large electromagnetic force cannot be generated in a relatively small current region of the rated current, and the arc generated at the contact opening is appropriately applied. There is a concern that it cannot be moved to the arc extinguishing device. Therefore, the arc generated between the contacts at the time of current interruption (contact opening operation) must be interrupted in a state of stagnation at a short distance between both contacts, and in order to cope with high voltage in a DC circuit having no current zero, Requires contact opening distance. As a result, there is a problem that the arc extinguishing device and the product are enlarged.

In contrast, in the present embodiment, since a permanent magnet is used as the magnetic drive yoke, a constant electromagnetic force can be generated regardless of the magnitude of the current. Therefore, sufficient electromagnetic force can be generated even in a relatively small current region of about the rated current, and the arc generated at the time of contact opening can be appropriately moved to the arc dissipation device.

As described above, the current interruption using the arc dissipation device provided by the circuit breaker in a wider current range can be efficiently performed.

(effect)

As described above, in the first embodiment, a pair of front and rear magnetic drive yokes are arranged so as to sandwich the side portions of both ends of the movable contactor, respectively, so that when a current flows in the movable contactor in the closed electrode state, between the fixed contactor and the movable contactor. A strong electromagnetic repulsion force (Lorentz force) can be generated to drive the movable contact in the direction of opening away from the fixed contact. In the contact opening operation, the arc generated between the contacts can be driven in the direction of the arc dissipation device by the Lorentz force.

At this time, since the permanent magnet is used as the magnetic drive yoke, it can have a constant magnetic flux regardless of the magnitude of the current. Therefore, even in a relatively small current region, it is possible to efficiently drive the arc generated between the contacts during the contact opening operation in the direction of the arc dissipation device.

Therefore, in the direct current | flow interruption | blocking of the low current area | region which was difficult to respond with the conventional structure, the extensive current interruption | blocking using the arc quenching apparatus can be reliably ensured. Therefore, it is possible to contribute to the provision of a small arc dissipation device suitable for a DC circuit and to reduce the size of the main body of the product, and to realize a lot of common parts with the AC-only product, thereby achieving a low cost circuit breaker.

In addition, since the magnetic drive yoke is made of a U-shaped permanent magnet, the U-shaped both legs can reliably sandwich the side portions of both ends of the movable contact. In addition, since the magnetic drive yoke is used as a single member, the arc current plate can be formed in a band shape, and the arc current plate can be easily formed as compared with the case where the arc current plate is integrated with the arc current plate. The degree of freedom of placement can be increased.

In the contact opening operation process, although the high pressure conductive gas generated by the arc is filled in the vicinity of the contact, the short circuit between the magnetic drive yokes can be prevented from occurring by completely covering both legs of the magnetic drive yoke with an insulating cover. Can be.

(Second Embodiment)

Next, a second embodiment of the present invention will be described.

In the second embodiment, in the above-described first embodiment, the U-shaped magnetic drive yoke 10 is applied, but the magnetic drive yoke 10 is integrally formed with the arc current plate 9. It is configured.

(Configuration)

FIG. 7: is sectional drawing which shows the structure of the current interruption | blocking part 1 of 2nd Embodiment.

As shown in FIG. 7, the current interruption unit 1 of the present embodiment is the same as that of the current interruption unit 1 in FIG. 1 except that the configuration of the magnetic drive yoke is different. It has the same structure as the current interruption unit 1. Therefore, the same code | symbol is attached | subjected to the part which has a structure like FIG. 1, and it demonstrates centering around a part with a different structure here.

In the present embodiment, an arc current plate 19 is used instead of the arc current plate 9, and a rectangular magnetic drive yoke 20 is used instead of the magnetic drive yoke 10.

8 is an exploded perspective view showing the structure of the magnetic drive yoke portion of the second embodiment.

As shown in Fig. 8, U-shaped magnetic bodies 19a and 19b that are bent and molded on the movable contactor 4 side at positions at both ends of the movable contactor 4 in the front and rear directions of the arc current plate 19, respectively. Is formed.

Further, the magnetic drive yoke 20 is made of a rectangular permanent magnet, and the lower surface thereof is fixed to the upper surfaces of both legs of the U-shaped magnetic bodies 19a and 19b of the arc current plate 19, whereby the arc current plate 19 It is integrated with). At this time, the magnetic drive yoke 20 is disposed so that the other magnetic poles face each other so as to have the polarity shown in FIG. 9 in the width direction (left and right directions) of the movable contact 4.

At the time of assembling the circuit breaker, the U-shaped magnetic bodies 19a and 19b and the magnetic body are fixed while the magnetic drive yokes 20 are fixed to the upper surfaces of both legs of the U-shaped magnetic bodies 19a and 19b formed on the arc current plate 19. An insulating cover 11 having the same configuration as that of the first embodiment described above is covered with the drive yoke 20.

As a result, the side surfaces of the movable contactors 4 are sandwiched between the magnetic contact yokes 20 fixed to both leg portions of the U-shaped magnetic bodies 19a and 19b. That is, both leg portions of the U-shaped magnetic bodies 19a and 19b are formed so short that the magnetic drive yoke 20 is arranged in the movable range of the movable contact 4.

(action)

Next, the operation of the second embodiment will be described.

In the closed electrode state, when a large current I such as a short circuit current flows and the fixed contacts 2a and 3a of the fixed contacts 2 and 3 and the movable contacts 4a and 4b of the movable contact 4 are separated, An arc occurs between the stationary contacts 2 and 3 and the movable contact 4.

As shown in Fig. 9, this arc A is in communication with the magnetic flux Φ strengthened by the magnetic drive yoke 20, so that the force F2 directed to the outside of the front and back directions of the movable contact 4 acts on the arc A. do. Thereby, this arc A moves to the arc extinction apparatus 6 arrange | positioned at the both ends of the movable contact 4.

In this manner, as in the first embodiment described above, the arc generated around the energization path at the time of contact opening can be appropriately moved to the arc dissipation device side.

(effect)

Thus, in 2nd Embodiment, since a magnetic drive yoke is comprised integrally with an arc current board, assembly of a circuit breaker and component management become easy.

Moreover, since the magnetic drive yoke is made rectangular, compared with the U-shaped magnetic drive yoke in the above-described first embodiment, the size of the permanent magnet can be reduced, and the cost can be reduced by that amount.

(Third Embodiment)

Next, a third embodiment of the present invention will be described.

In the third embodiment, the inner surface of both legs of the U-shaped magnetic body is fixed while the magnetic drive yoke is fixed to the upper surfaces of both legs of the U-shaped magnetic body formed on the arc current plate. To be fixed on.

(Configuration)

The current interruption unit 1 of the present embodiment has the same configuration as the current interruption unit 1 of FIG. 8 except that the magnetic drive yoke unit is different in the current interruption unit 1 shown in FIG. 8. Has Therefore, it demonstrates centering around a different part here.

FIG. 10 is an exploded perspective view showing the structure of the magnetic drive yoke portion of the third embodiment. FIG.

As shown in FIG. 10, U-shaped magnetic bodies 29a and 29b are formed at both ends of the movable contactor 4 in the front and rearward directions of the arc current plate 29, respectively, which are bent and molded on the movable contactor side. have. Moreover, the step part 29c for fixing the magnetic drive yoke 30 is formed in the inside of both leg parts of these U-shaped magnetic bodies 29a and 29b.

The magnetic drive yoke 30 is formed of a rectangular permanent magnet having a thickness equivalent to that of the stepped portion 29c, and is fixed to the stepped portion 29c formed on the arc current plate 29 to thereby be integrated with the arc current plate 29. It is composed of. That is, the magnetic drive yoke 30 is fixed to the inner surfaces of both leg portions of the U-shaped magnetic bodies 29a and 29b. At this time, the magnetic drive yoke 30 is disposed so that the other magnetic poles face each other so as to have the polarity shown in FIG. 11 in the width direction (left and right directions) of the movable contact 4.

In assembling the circuit breaker, the U-shaped magnetic bodies 29a and 29b and the magnetic drive yoke 30 are described above in a state where the magnetic drive yoke 30 is fixed to the stepped portion 29c formed on the arc current plate 29. An insulating cover 11 having the same configuration as that of the first and second embodiments is covered.

Thereby, the side part of the movable contact 4 is interposed between the magnetic contact yokes 30 fixed to the both leg portions of the U-shaped magnetic bodies 29a and 29b. That is, both leg portions of the U-shaped magnetic bodies 29a and 29b are formed long enough to arrange the magnetic drive yoke 30 in the movable range of the movable contact 4.

(action)

Next, the operation of the third embodiment will be described.

In the closed electrode state, when a large current I such as a short circuit current flows and the fixed contacts 2a and 3a of the fixed contacts 2 and 3 and the movable contacts 4a and 4b of the movable contact 4 are separated, An arc occurs between the stationary contacts 2 and 3 and the movable contact 4.

As shown in FIG. 11, this arc A is in linkage with the magnetic flux Φ strengthened by the magnetic drive yoke 30, so that a force F2 directed toward and outside of the movable contactor 4 acts on the arc A. do. Thereby, this arc A moves to the arc extinction apparatus 6 arrange | positioned at the both ends of the movable contact 4.

In this manner, as in the first and second embodiments described above, the arc generated around the energization path at the time of contact opening can be appropriately moved to the arc dissipation device side.

By the way, in the case of the structure which fixes the magnetic drive yoke 30 to the upper surface of both leg parts of the U-shaped magnetic body 19a, 19b formed in the arc current board 19 like 2nd Embodiment, as shown in FIG. Similarly, leakage magnetic flux? 'From the permanent magnet is generated. Therefore, the electromagnetic force for driving the arc A generated between the contacts to the arc dissipation device 6 side cannot be generated efficiently.

On the other hand, in this embodiment, the magnetic drive yoke 30 which consists of permanent magnets is fixed to the inner surface of both leg part of U-shaped magnetic body 29a, 29b. In other words, the U-shaped magnetic bodies 29a and 29b are disposed outside the magnetic drive yoke 30 made of a permanent magnet. Therefore, the leakage magnetic flux Φ 'from the permanent magnet as shown in FIG. 12 can be reduced, whereby the electromagnetic force for driving the arc A generated between the contacts to the arc extinguishing device 6 side can be efficiently generated. have.

(effect)

Thus, in 3rd Embodiment, since a magnetic drive yoke is comprised integrally with an arc current board, assembly of a circuit breaker and component management become easy.

Moreover, since the magnetic drive yoke is made rectangular, compared with the U-shaped magnetic drive yoke in the above-described first embodiment, the size of the permanent magnet can be reduced, and the cost can be reduced by that amount.

In addition, since the magnetic drive yoke is fixed to the inner surface of both legs of the U-shaped magnetic body of the arc current plate, the leakage magnetic flux from the permanent magnet can be reduced, and the arc generated between the contacts can be efficiently moved to the arc dissipation device side. have.

In addition, since the magnetic drive yoke is fixed to the stepped portion formed in the U-shaped magnetic body of the arc current plate, the thickness of the permanent magnet can be made thinner as compared with the magnetic drive yoke of the second embodiment described above. Can be reduced. In addition, since the magnetic drive yoke can be adsorbed on the stepped portion, positioning of the magnetic drive yoke becomes easier and easier to assemble, as compared with the case where the magnetic drive yoke is simply fixed to the inner surface of both legs of the U-shaped magnetic body without the step. It can simplify sex.

According to the circuit breaker according to the present invention, it is possible to contribute to the provision of a small circuit breaker suitable for a DC circuit and to downsize the main body of the product, and to share a lot of components with AC-only products, thereby providing a low cost circuit breaker. It is useful.

1: current breaker 2, 3: fixed contactor
2a, 3a: fixed contact 4: movable contact
4a, 4b: movable contact 5: contact spring
6: arc extinction device 7: grid
8, 11a, 11b: side walls 9, 19, 29: arc current plate
10, 20, 30: magnetic drive yoke 10a, 10b: leg portion
11: Insulation cover 19a, 19b, 29a, 29b: U-shaped magnetic body
29c: stepped portion

Claims (4)

A pair of front and rear fixed contacts arranged to face each other, a linear movable contact member which intersects the fixed contact member, and the front and rear sides arranged so as to sandwich the side portions of both ends of the movable contact member, respectively. Has a pair of magnetically driven yokes at each pole,
When the movable contact is pressed against the fixed contact by the contact spring, each pole conduction path is closed, and the movable contact is pressed against the contact spring by the opening / closing mechanism, and the contact is opened from the fixed contact. Is configured to open the conduction path by
And the magnetic drive yoke is made of a permanent magnet. The circuit breaker according to claim 1, wherein the magnetic drive yoke is made of a U-shaped permanent magnet, and is disposed so as to sandwich the side portions of the movable contact on each leg. 2. The fixed contactor and the movable contactor according to claim 1, further comprising a pair of arc dissipating devices disposed before and after the movable contactor, and disposed below the movable contact so as to span between these arc dissipating devices. An arc current plate for causing a current on the movable contact side of the arc generated between the arc current plates,
The arc current plate has a pair of U-shaped magnetic bodies formed by bending on the movable contact side,
The magnetic drive yoke is made of a rectangular permanent magnet, the bottom of which is fixed to the upper surface of both legs of the U-shaped magnetic body, the circuit breaker, characterized in that arranged so as to sandwich the side portions of the movable contact between each. 2. The fixed contactor and the movable contactor according to claim 1, further comprising a pair of arc dissipating devices disposed before and after the movable contactor, and disposed below the movable contact so as to span between these arc dissipating devices. An arc current plate for causing a foot on the movable contact side of the arc generated between the arc current plates,
The arc current plate has a pair of U-shaped magnetic bodies formed by bending on the movable contact side,
The magnetic drive yoke is made of a rectangular permanent magnet, and is fixed to the inner surfaces of both legs of the U-shaped magnetic body, so that the circuit breaker is arranged so as to sandwich the side portions of the movable contact therebetween.

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