CN103069532A - Circuit breaker - Google Patents

Abstract

To provide a circuit breaker capable of appropriately diverting an arc between contacts to an arc extinguishing device even in a relatively small current region without causing an increase in size of the equipment. At each pole there are: a pair of front/rear fixed contacts (2,3) arranged facing each other; a movable contact (4) formed as a fixed contact (2,3) and a pair of front/rear magnetic drive yokes (10) including permanent magnets arranged to clamp inner sections of both ends of the movable contact (4). In the closed state, the movable contact (4) closes the current path at each pole by pressing onto the fixed contacts (2, 3) by means of a contact spring (5). In the open state, the movable contact (4) opens the above-mentioned current path by being separated from the fixed contacts (2, 3) due to being pressed against the contact spring (5) by the opening mechanism.

Description

breaker

technical field

The present invention relates to a circuit breaker for wiring protection, and more particularly to a circuit breaker with a linear motion two-contact structure.

Background technique

For example, the technique described in Patent Document 1 exists as a conventional circuit breaker. In this technology, a U-shaped magnetic body is arranged outside the movable contact and the fixed contact of different current paths. When a large current such as a short-circuit current is applied, this configuration can generate an electromagnetic repulsive force (Lorentz force) in the repulsive direction between the contacts, and can move away from the fixed contact by operating the movable contact to improve interrupt performance. This configuration also enables the arc generated between the contacts after the contacts are opened to move to the arc extinguishing devices provided at both end sides of the movable contact.

PRIOR ART DOCUMENTS Patent Document 1: Patent No. 3859053

Contents of the invention

The technical problem solved by the invention

Incidentally, the electromagnetic force generated by the magnetic body is proportional to the current. Therefore, in the case of the above circuit breaker, a current region in which a relatively small current such as a rated current flows cannot generate a large electromagnetic force.

For this reason, the low current region lacks the power to move the arc generated when the contacts open to the arc crowbar. Interruption is required when the arc generated between the contacts stagnates within a short distance between the contacts when the current is interrupted (during contact opening operation). The opening distance between the contacts needs to be increased to handle the high voltages in direct current (DC) circuits that do not have a current zero point. This causes upsizing of the arc extinguishing device and the equipment with the circuit breaker.

It is therefore an object of the present invention to provide a circuit breaker which, even in relatively small current regions, allows the arc generated between the contacts to move appropriately to the arc crowbar without causing the arc crowbar to of upsizing.

technical means to solve problems

In order to achieve the above object, the first aspect of the circuit breaker according to the present invention is a circuit breaker including a pair of front/rear fixed contacts arranged to face each other in each pole, formed as a fixed contact The linear motion type movable contact of the bridge between the parts and a pair of front/rear magnetic drive yokes, the pair of front/rear magnetic drive yokes are arranged to hold the side parts on both ends of the movable contact between them , wherein the movable contact closes the current feeding path of each pole by being pressed against the fixed contact by the contact spring, and opens the current feeding path by being pressed back toward the contact spring by the opening/closing mechanism to communicate with the fixed The contacts are separated, and the magnetic drive yoke consists of permanent magnets.

According to this configuration, when current flows to the movable contact in the closed state, the current interlinks with the magnetic flux converged by the magnetically driven yoke (Japanese: interlocking), and responds to a strong electromagnetic repulsive force (Lorentz force) to drive the movable contact to separate from the fixed contact. An arc is generated between each fixed contact and a movable contact during a contact opening operation. The generated arc is driven by interlinking with the magnetic flux strengthened by the magnetic driving yoke, moves to arc extinguishing devices provided in front and rear of the movable contact, and then the arc is extinguished.

Since the magnetic drive yoke is made of permanent magnets, a constant magnetic flux is obtained regardless of the current level. Therefore, even in a relatively small current region, each arc generated between the contacts can be efficiently driven to move to the arc extinguishing device at the time of the contact opening operation.

In a second aspect, the magnetic drive yokes are formed of U-shaped permanent magnets and arranged such that the feet of each of the magnetic drive yokes hold the side portions of the movable contact therebetween.

Since the magnetic drive yoke is composed of U-shaped permanent magnets, the feet of the U-shaped magnetic drive yoke can securely hold the side portions on both ends of the movable contact between them. Furthermore, the magnetic drive yoke can be placed in any desired position. This increases the degree of freedom in arranging the magnetic drive yoke.

In addition, a third aspect of the present invention is a circuit breaker having a pair of arc extinguishing devices and an arc commutator plate (Japanese: アワ・㢢テララ) provided in front and rear of the movable contact. , the arc commutation plate is arranged below the movable contact in such a manner as to extend above the arc extinguishing device and commutate the bottom of the arc on the movable contact side, which is generated at the movable contact when the current is interrupted and the fixed contact piece, wherein the arc commutator plate has a pair of U-shaped magnetic bodies bent toward the movable contact piece, and the magnetic drive yoke is composed of a rectangular permanent magnet, and is arranged such that its lower surface is fixed to the U-shaped magnetic body The upper surfaces of the two feet of the to hold the side surfaces of the movable contact between them.

Due to the configuration in which the magnetic drive yoke is composed of rectangular permanent magnets, the permanent magnets can be made smaller than when the magnetic drive yoke is composed of U-shaped permanent magnets, thereby achieving cost reduction. Furthermore, since the magnetic drive yoke is integrally constructed with the arc commutator plate, the number of components of the circuit breaker can be reduced, thereby simplifying assembly of the circuit breaker.

A fourth aspect of the present invention is a circuit breaker having a pair of arc extinguishing devices provided in front and rear of the movable contact, and an arc commutator plate provided to The arc device extends above and commutates the bottom of the arc on the movable contact, which arc is generated between the movable contact and the fixed contact when the current is interrupted, wherein the arc commutation plate has a direction towards the movable A pair of U-shaped magnets of which the contacts are bent, and a magnetic drive yoke constituted by rectangular permanent magnets, are arranged to hold the sides of the movable contact between them by being fixed to the inner surfaces of the feet of the U-shaped magnets.

Since the rectangular permanent magnet is fixed to the inner surface of the foot of the U-shaped magnet bent in the arc commutation plate, the leakage magnetic flux of the permanent magnet can be reduced more than when the permanent magnet is fixed to the end of the foot of the U-shaped magnet. Thus, the arc generated between the contacts at the time of the contact opening operation can be effectively driven to move to the arc extinguishing device.

Invention effect

According to the present invention, since the magnetic drive yoke is composed of permanent magnets, even in a relatively small current region, each arc generated around each current feeding path at the time of contact opening operation can be effectively driven to move to the arc suppression device. Therefore, the present invention can provide a miniature circuit breaker which is suitable for direct current circuits and contributes to downsizing of equipment having the circuit breaker. Furthermore, parts of the circuit breaker can be replaced with parts dedicated to AC circuits. Therefore, an inexpensive circuit breaker can be provided by the present invention.

Description of drawings

1 is a cross-sectional view showing the structure of a current interrupting portion of a circuit breaker according to an embodiment of the present invention;

2 is an exploded perspective view showing the structure of a magnetic drive yoke according to the first embodiment;

3 is a cross-sectional view showing the structure of a current interrupting portion in a contact closed position;

4 is a cross-sectional view showing the vicinity of contacts according to the first embodiment, which shows vectors of current, magnetic flux, and electromagnetic repulsion;

5 is a plan view showing the vicinity of contacts according to the first embodiment, which shows vectors of current, magnetic flux, and electromagnetic repulsion;

6 is a view showing the traveling direction of the arc and the structure of the current interrupting portion when in the contact open position according to the first embodiment;

7 is a cross-sectional view showing the structure of a current interrupt portion according to a second embodiment;

8 is an exploded perspective view showing the structure of a magnetic drive yoke according to a second embodiment;

9 is a plan view showing the vicinity of contacts according to the second embodiment, which shows vectors of current, magnetic flux, and electromagnetic repulsion;

10 is an exploded perspective view showing the structure of a magnetic drive yoke according to a third embodiment;

11 is a plan view showing the vicinity of contacts according to the third embodiment, which shows vectors of current, magnetic flux, and electromagnetic repulsion;

FIG. 12 is a view showing a leakage magnetic flux of a magnetically driven yoke; and

FIG. 13 is a view of the structure of a current interrupting portion of a conventional circuit breaker.

Detailed ways

Embodiments according to the present invention will be described below with reference to the drawings.

(first embodiment)

(structure)

FIG. 1 is a cross-sectional view showing a current interrupting portion of a circuit breaker according to an embodiment of the present invention. The circuit breaker according to the present embodiment is a circuit breaker having a linearly moving two-contact structure.

In the illustration, reference numeral 1 designates a current interruption. In each phase current feeding path, U-shaped fixed contacts 2, 3 constituted by rectangular conductors are provided at the front and rear of the current interrupting portion so as to face each other. The fixed contacts 2a, 3a are attached to the fixed contacts 2, 3, respectively. A rectangular movable contact member 4 bent downward at both ends has a pair of movable contacts 4a and 4b capable of contacting fixed contacts 2a and 3a, respectively. In the closed state where each current feeding path is closed, the movable contact 4 acts as a bridge between the fixed contacts 2 and 3 by being pressed against the fixed contacts 2 and 3 by the contact spring 5 which is a compression spring, Thus, the movable contacts 4a and 4b are in contact with the fixed contacts 2a and 3a, respectively. In the open state where the current feeding path is open, the movable contact 4 is separated from the fixed contacts 2, 3 by being pressed down toward the contact spring 5 by an unshown opening/closing mechanism, as shown in the drawings.

A pair of arc extinguishing devices 6 are provided in front and rear of the movable contact 4 . A plurality of grids 7 of the arc extinguishing device 6 surrounds the end of the movable contact 4 . The grids 7 are each composed of U-shaped magnetic plates and are supported by a pair of left/right insulating side walls 8 as shown in plan view. Arc deflectors 9 made of a highly resistant material such as steel plates are provided below the arc extinguishing device 6 to extend over the front and rear arc extinguishing devices 6 . The arc commutator plate 9 functions as a support plate for the contact spring 5 .

Reference numeral 10 in the drawings denotes a pair of front/rear magnetic drive yokes composed of U-shaped permanent magnets. The magnetic drive yokes 10 are arranged such that the left and right foot portions of each magnetic drive yoke hold the side portions on the ends of the movable contacts 4 between the feet. One of the feet forms the south pole, while the other forms the north pole. Each magnetic drive yoke is arranged to achieve the polarity shown in FIG. 5 . Left and right foot portions of the magnetic drive yoke 10 are covered with insulating covers 11 .

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

The insulating cover 11 is formed into a U-shape by resin molding, and has a pair of left/right side walls 11a, 11b in which the movable contact 4 is held so as to be able to move between the side walls 11a, 11b in the opening/closing direction ( vertical direction in Figure 1) movement. The lower surface of each of the side walls 11a, 11b of the insulating cover 11 is opened to form a pocket. The bag covers the feet 10a, 10b of the magnetic drive yoke 10 when the circuit breaker is assembled. When assembling the circuit breaker, the arc commutator plate 9 is disposed between the leg portions 10a, 10b of the magnetic drive yoke 10, and outside the lower surface portion of the insulating cover 11.

(operate)

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

Fig. 3 is a cross-sectional view showing the structure of a current interrupt portion in a contact closed position. FIG. 4 is a sectional view showing the vicinity of each contact. FIG. 5 is a plan view showing the vicinity of each contact. FIG. 6 is a view showing the structure of the contact interruption portion and the arc traveling direction when in the contact open position.

In the closed state shown in FIG. 3, it is assumed that a large current I such as a short-circuit current flows as indicated by an arrow in the figure. At this time, as shown in FIG. 4 , it is assumed that the current I flows from the top to the bottom within the movable contact 4 in a direction perpendicular to the sheet of FIG. 4 . The magnetic flux φ based on the current I is concentrated by the magnetic drive yoke 10 , and passes through the movable contact 4 and the magnetic drive yoke 10 in the clockwise direction. In this state, since the magnetic flux φ passing through the movable contact 4 from left to right in Fig. 4 intersects with the current I flowing through the movable contact 4, based on Fleming's left-hand rule, as shown in Fig. 4 As shown, the downward electromagnetic repulsive force (Lorentz force) F1 acts on the movable contact piece 4 .

Simultaneously, an overcurrent detector not shown detects an overcurrent and outputs a trip signal, in response to which the opening/closing mechanism pushes the movable contact 4 downward as shown in FIG. 3 . Thereby, the fixed contacts 2 a and 3 a of the corresponding fixed contacts 2 and 3 are pulled away from the movable contacts 4 a and 4 b of the movable contact 4 .

Therefore, the movable contact 4 is driven to separate from the fixed contact at a higher speed than driving the movable contact with only the electromagnetic repulsion force or with only the opening/closing mechanism. Thereby, the interrupting performance of the circuit breaker can be improved.

An arc is generated between the movable contact 4 and the fixed contacts 2 and 3 at the contact opening operation in which the fixed contacts 2 a and 3 a are separated from the movable contacts 4 a and 4 b. Since this arc A intersects the magnetic flux φ (the magnetic flux from left to right in Fig. 4), which is intensified by the magnetic drive yoke 10 as shown in Fig. 5, based on Fleming's left-hand rule, the force F2 along the movable contact The forward/backward direction of 4 acts outwardly on arc A. Therefore, as shown in FIG. 6, the arc A generated between the contacts is diverted from arc A1 -> arc A2 -> arc A3 -> arc A4 toward each of the arc extinguishing devices 6, which The arc device 6 is provided outwardly in the front/rear direction of the movable contact 4 . The arc A drawn to each of the arc extinguishers 6 is analyzed, cooled and extinguished. Thus, the short-circuit interrupting operation is completed.

By doing so, due to the arc commutator plate 9 provided inside the circuit breaker, the bottom of the arc A on the side of the movable contact 4 moves to the arc commutator plate 9 and is extinguished, thus, current does not flow through the movable contact Part 4, thereby preventing the movable contact part 4 from being damaged by a large current.

In the prior art, magnetic bodies are used as magnetic drive yokes.

FIG. 13 is a view of the structure of a current interrupting portion of a conventional circuit breaker. FIG. 13( a ) is a plan view of the current interrupting portion, and FIG. 13( b ) is a front view of the current interrupting portion. FIG. 13 shows an example in which a magnetic drive yoke 110 composed of magnets is integrated with an arc commutation plate 109 . In other words, the pair of front/rear drive magnets 110 is bent integrally with the arc commutator plate 109 and extends vertically in the direction in which the movable contact 104 moves to separate from the fixed contact.

In this configuration, when a large current such as a short circuit current flows, an electromagnetic repulsive force is generated between the contacts as in the present embodiment, whereby the movable contact 104 can be operated to be separated from the fixed contact. In addition, after the contact opening operation, an electromagnetic force for moving an arc generated between the contacts toward the arc extinguishing device may be generated.

However, when a magnet is used as a magnetic drive yoke, since the electromagnetic force generated by the magnet is proportional to the current, a current region where a relatively small current such as a rated current flows cannot generate a large electromagnetic force. For this reason, the arc generated at the time of the contact opening operation cannot properly move toward each arc extinguishing device. When an arc is generated between the contacts when the current is interrupted (at the time of contact opening operation), interruption is required in case the arc stagnates within a short distance between the contacts. The opening distance between the contacts needs to be increased to handle the high voltages in DC circuits that do not have a current zero point. This causes upsizing of the arc extinguishing device and the equipment with the circuit breaker.

However, in this embodiment, since the magnetic drive yoke is composed of permanent magnets, a constant electromagnetic force can be generated regardless of the current level. Therefore, even in the current region where the current is as small as the rated current, sufficient electromagnetic force can be generated, and the arc generated between the contacts at the time of the contact opening operation can be appropriately moved toward each arc extinguishing device.

As described above, this embodiment can perform current interruption in a wide range of current regions by effectively utilizing the arc extinguishing device of the circuit breaker.

(Effect)

In the first embodiment, as described above, since the pair of front/rear magnetic drive yokes are arranged to hold the side portions of the ends of the movable contacts between them, when current flows to the movable contacts in the closed state When the contactor is connected, a strong electromagnetic repulsive force (Lorentz force) can be generated between the movable contactor and the fixed contactor, whereby the movable contactor can be driven to separate from the fixed contactor. In addition, the arc generated between the contacts can be driven by the Lorentz force to move toward each arc extinguishing device during the opening operation of the contacts.

Since the magnetic drive yoke is made of permanent magnets, a constant magnetic flux is obtained regardless of the current level. Therefore, even in a relatively small current region, an arc generated between the contacts at the time of the contact opening operation can be efficiently driven to move to each arc extinguishing device.

Therefore, although it is difficult to perform DC interruption in a small current region in the conventional structure, a larger range of current interruption can be safely achieved by using an arc extinguishing device. Therefore, the present invention can provide a small arc extinguishing device which is suitable for direct current circuits and contributes to downsizing of the entire equipment having the circuit breaker of the present invention. Furthermore, parts of the circuit breaker can be replaced with parts dedicated to AC circuits. Therefore, an inexpensive circuit breaker can be realized by the present invention.

The magnetic drive yoke consists of U-shaped permanent magnets. Therefore, the U-shaped foot portion of each magnetic drive yoke can firmly hold the side portion of the end portion of the movable contact. Since the magnetically driven yoke is provided as a separate member, not only can the arc commutator plate be shaped into a strip shape, but the arc commutator plate can also be molded more easily than when the magnetically driven yoke is integrated with the arc commutator plate, thereby increasing the set magnetic degrees of freedom to drive the yoke.

Furthermore, during the opening operation of the contacts, the section near the contacts is filled with a high-voltage conductive gas generated by the arc. However, covering the entire legs of the magnetic drive yokes with insulating covers prevents phase-to-phase short circuits between the magnetic drive yokes.

(second embodiment)

A second embodiment of the present invention is described below.

Although the U-shaped magnetic drive yoke 10 is applied to the first embodiment described above, the magnetic drive yoke 10 is constructed integrally with the arc commutation plate 9 in the second embodiment.

(structure)

FIG. 7 is a cross-sectional view of the structure of the current interrupt portion 1 according to the second embodiment.

As shown in FIG. 7 , the configuration of the current interrupting portion 1 of the present embodiment is the same as that of the current interrupting portion 1 shown in FIG. 1 except for the configuration of the magnetically driven yoke. Therefore, the same reference numerals are applied to components having the same configuration as those shown in FIG. 1 , and components of a different configuration are described in this embodiment.

In this embodiment, instead of the arc commutator plate 9 , an arc commutator plate 19 is employed, and instead of the magnetically driven yoke 10 , a rectangular magnetically driven yoke 20 is employed.

Fig. 8 is an exploded perspective view of the structure of a magnetic drive yoke according to the second embodiment.

As shown in FIG. 8 , U-shaped magnets 19 a , 19 b bent toward the movable contact 4 are respectively formed at positions of ends of the movable contact 4 in the front/rear direction of the arc commutator plate 19 .

In addition, the magnetic drive yoke 20 is composed of rectangular permanent magnets. The lower surface of the magnetic drive yoke 20 is fixed to the upper surfaces of the two feet of the U-shaped magnets 19 a , 19 b of the arc commutation plate 19 and thus integrated with the arc commutation plate 19 . By doing so, the magnetic drive yoke 20 is arranged to obtain the polarity shown in FIG. 9 in the width direction (lateral direction) of the movable contact 4 in which different magnetic poles face each other.

When assembling the circuit breaker, the magnetic drive yoke 20 is fixed to the upper surfaces of the two legs of the U-shaped magnets 19a, 19b of the arc commutator plate 19, and the insulating cover 11 having the same configuration as in the first embodiment is placed on the U Shaped magnets 19a, 19b and magnetic drive yoke 20.

In this way, the side portions of the movable contact 4 are held by the magnetic drive yoke 20 fixed to the feet of the U-shaped magnets 19a, 19b. In particular, the legs of the U-shaped magnets 19a, 19b are made shorter in order to place the magnetic drive yoke 20 within the range of motion of the movable contact 4 .

(operate)

The operation of the second embodiment is described below.

In the closed 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 are pulled away from the movable contacts 4a and 4b of the movable contact 4, at An arc is generated between the movable contact 4 and the fixed contacts 2 and 3 .

The arc A interlinks the magnetic flux φ reinforced by the magnetic drive yoke 20 as shown in FIG. 9 . Therefore, the force F2 acts outwardly on the arc A in the front/rear direction of the movable contact 4 . Thus, the arc A moves to each arc extinguishing device 6 provided in each end portion of the movable contact 4 .

As in the first embodiment, the arc generated around each current feeding path at the time of the contact opening operation can properly move toward each arc extinguishing device.

(Effect)

As mentioned above, the magnetic drive yoke is constructed integrally with the arc commutation plate in the second embodiment. Therefore, assembly of the circuit breaker and management of components of the circuit breaker can be easily realized.

Also, due to the rectangular shape of the magnetic drive yoke, the size of each permanent magnet can be smaller than that of the U-shaped magnetic drive yoke of the first embodiment described above, thereby reducing costs.

(third embodiment)

A third embodiment of the present invention is described below.

The magnetic drive yoke is fixed to the upper surface of the foot of the U-shaped magnet formed in the arc commutator plate in the second embodiment, while in the third embodiment the magnetic drive yoke is fixed to the inner surface of the foot of the U-shaped magnet .

(structure)

As shown in FIG. 8 , the configuration of the current interrupting portion 1 of the present embodiment is the same as that of the current interrupting portion 1 shown in FIG. 1 except for the configuration of the magnetically driven yoke. Therefore, components of different configurations are mainly described in this embodiment.

Fig. 10 is an exploded perspective view showing the structure of a magnetic drive yoke according to a third embodiment.

As shown in FIG. 10 , U-shaped magnets 29 a , 29 b bent toward the movable contact 4 are respectively formed at end positions of the movable contact 4 in the front/rear direction of the arc commutator plate 29 . A stepped portion 29c, to which the magnetic drive yoke 30 is fixed, is formed inside the two leg portions of the U-shaped magnets 29a, 29b.

The magnetic drive yoke 30 is composed of a rectangular permanent magnet as thick as the stepped portion 29c, and is constructed integrally with the arc commutator plate 29 by being fixed to the stepped portion 29c formed in the arc commutator plate 29. In other words, the magnetic drive yoke 30 is fixed to the inner surfaces of the two feet of the U-shaped magnets 29a, 29b. At this time, the magnetic drive yoke 30 is arranged so as to obtain the polarity shown in FIG. 11 in the width direction (lateral direction) of the movable contact 4 in which different magnetic poles face each other.

When assembling the circuit breaker, the magnetic drive yoke 30 is fixed to the stepped portion 29c of the arc commutator plate 29, and the insulating cover 11 having the same configuration as in the first and second embodiments is placed on the U-shaped magnets 29a, 29b and the magnetic drive Yoke 30 on.

In this way, the side portions of the movable contact 4 are held between the magnetic drive yokes 30 fixed to the feet of the U-shaped magnets 29a, 19b. Specifically, the legs of the U-shaped magnets 29a, 29b are made longer to allow the magnetic drive yoke 30 to be placed within the range of motion of the movable contact 4 .

(operate)

The operation of the third embodiment is described below.

In the closed 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 are pulled away from the movable contacts 4a and 4b of the movable contact 4, at An arc is generated between the movable contact 4 and the fixed contacts 2 and 3 .

The arc A interlinks the magnetic flux φ reinforced by the magnetic drive yoke 30 as shown in FIG. 11 . Therefore, the force F2 acts outwardly on the arc A in the front/rear direction of the movable contact 4 . Thus, the arc A moves to each arc extinguishing device 6 provided in each end portion of the movable contact 4 .

As in the first and second embodiments, the arc generated around each current feeding path at the time of contact opening operation can be properly moved to each arc extinguishing device.

Incidentally, when the magnetic drive yoke 30 is fixed to the upper surfaces of the feet of the U-shaped magnets 19a, 19b of the arc commutator plate 19 in the same manner as described in the second embodiment, leakage magnetic flux of the permanent magnets is generated φ'. This configuration cannot generate an electromagnetic force for driving the arc A generated between the contacts toward the arc extinguishing device 6 .

In this embodiment, on the other hand, a magnetic drive yoke 30 of permanent magnets is fixed to the inner surface of the feet of the U-shaped magnets 29a, 29b. In other words, the U-shaped magnets 29a, 29b are located outside the magnetic drive yoke 30 of the permanent magnets. Therefore, the leakage magnetic flux φ' of the permanent magnet shown in FIG.

(Effect)

As mentioned above, the magnetic drive yoke is constructed integrally with the arc commutation plate in the third embodiment. Therefore, assembly of the circuit breaker and management of components of the circuit breaker can be easily realized.

Furthermore, due to the rectangular shape of the magnetic drive yoke, the size of each permanent magnet can be smaller than that of the U-shaped magnetic drive yoke of the first embodiment described above, thereby reducing costs.

Furthermore, fixing the magnetic drive yoke to the inner surface of the foot of the U-shaped magnet of the arc commutator plate can reduce the leakage magnetic flux φ of the permanent magnet. Therefore, the arc generated between the contacts can be efficiently moved to each arc extinguishing device.

Furthermore, by fixing the magnetic drive yoke inside the U-shaped magnet, the permanent magnet can be made thinner than the magnetic drive yoke of the second embodiment described above, thereby achieving cost reduction. Furthermore, since the magnetic drive yoke can be adhered to the step, the magnetic drive yoke can be positioned more easily than when the magnetic drive yoke is fixed to the inner surface of the foot of the U-shaped magnet without any step. Therefore, assembly of the circuit breaker can be simplified.

Industrial applicability

The present invention can provide a miniature circuit breaker which is suitable for a DC circuit and contributes to downsizing of equipment having the circuit breaker. Furthermore, parts of the circuit breaker can be replaced with parts dedicated to AC circuits. Thus, the present invention can provide a low-cost circuit breaker, and it is useful.

Explanation of reference signs

1...circuit breaker, 2...fixed contact, 2a...fixed contact, 3...fixed contact, 3a...fixed contact, 4...movable contact, 4a, 4b...movable contact, 5...contact spring, 6...arc suppression device, 7...grid, 8...side wall, 9...arc converter plate, 10...magnetic drive yoke, 10a, 10b...foot, 11...insulating cover, 11a, 11b...side wall, 19... Arc commutation plate, 19a, 19b...U-shaped magnet, 20...Magnetic drive yoke, 29...Arc commutator plate, 29a, 29b...U-shaped magnet, 29c...Step portion, 30...Magnetic drive yoke

Claims (4)

1. circuit breaker, described circuit breaker comprises in extremely at each: a pair of front/rear fixed contact therefor that arranges with facing with each other; The movable contact of linear motion-type, described movable contact forms the bridgeware between the described fixed contact therefor; And a pair of front/rear magnetic drive yoke, described a pair of front/rear magnetic drive yoke is arranged to the side surface part on the two ends of described movable contact is remained between the described a pair of front/rear magnetic drive yoke,

Wherein, described movable contact makes the current feed path closed by being touched spring press at described fixed contact therefor, and by be opened/close mechanism pushes back to separate with described fixed contact therefor towards described contact spring and opens described current feed path, and

Described magnetic drive yoke is made of permanent magnet.

2. circuit breaker as claimed in claim 1 is characterized in that, described magnetic drive yoke is made of the U-shaped permanent magnet, and each the foot that is arranged in the described magnetic drive yoke remains on the side surface part of described movable contact between the described foot.

3. circuit breaker as claimed in claim 1 is characterized in that, comprising:

A pair of arc-extinction device, described a pair of arc-extinction device is arranged on the place ahead and the rear of described movable contact; And

Electric arc change of current plate, described electric arc change of current plate is with below being arranged on described movable contact in the mode of extending above the described arc-extinction device and the bottom in movable contact side of electric arc is carried out the change of current, described electric arc results from when current interruptions between described movable contact and the described fixed contact therefor

Described electric arc change of current plate has the pair of U-shaped magnet towards described movable contact bending, and

Described magnet is made of the rectangle permanent magnet, and the lower surface of being arranged to described magnet is fixed to the upper surface of two foots of described U-shaped magnet, remains between the described foot with the side surface with described movable contact.

4. circuit breaker as claimed in claim 1 is characterized in that, comprising:

A pair of arc-extinction device, described a pair of arc-extinction device is arranged on the place ahead and the rear of described movable contact; And

Electric arc change of current plate, described electric arc change of current plate is with below being arranged on described movable contact in the mode of extending above the described arc-extinction device and the bottom in movable contact side of electric arc is carried out the change of current, described electric arc results from when current interruptions between described movable contact and the described fixed contact therefor

Described electric arc change of current plate has the pair of U-shaped magnet towards described movable contact bending, and

Described magnetic drive yoke is made of the rectangle permanent magnet, and the inner surface of being arranged to the foot by being fixed to described U-shaped magnet remains on the side surface part of described movable contact between the described foot.

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