Circuit breaker

Abstract

To provide a circuit breaker that suppresses increase in size of a housing space of a circuit interrupter, and thus can be designed to be compact.SOLUTION: A circuit breaker includes: a fixed contactor 2 provided with a fixed contact 21; a movable contactor 3 provided with a movable contact 31 and capable of opening / closing the contacts by its operation; and a side wall part 41 provided on the movable contactor 3. In response to the movement of the side wall part 41 by an operation of the movable contactor 3 to open the contacts, air can be brown over an arc A that is generated when the contacts are opened.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a circuit breaker.

Background Art

[0002] In a circuit breaker in an energized state, when the movable contact and the fixed contact are separated due to an opening / closing operation of the handle or an overcurrent, the gas existing therebetween is broken down by the potential difference between the contacts and a current flows, generating an arc. Since this arc can cause a fire, it is desirable to extinguish the arc as quickly as possible. Particularly in the case of direct current, unlike alternating current, the voltage and current do not become zero and the arc does not extinguish naturally, so some arc extinguishing means is required. For this reason, conventionally, it has been known to provide an arc extinguishing device or a magnet inside a circuit breaker in order to quickly extinguish the arc.

[0003] Patent Document 1 describes a wiring breaker provided with an arc extinguishing device having a plurality of arc extinguishing plates and a metal magnetic body that attracts the arc toward the arc extinguishing device side. Further, Patent Document 2 describes a DC switch that arranges a permanent magnet protected by a case and bends and extinguishes the arc by magnetic force.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] These conventional arc extinguishing devices and arc extinguishing methods using magnets increase the resistance value by extending the distance of the arc to make it difficult for the current to pass through and extinguish the arc. In the arc extinguishing method from the viewpoint of extending the distance of the arc in this way, there are problems such as the need for space to arrange the arc extinguishing device and the complexity of the coating structure of the magnet to prevent the decrease in magnetic force due to heat.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The inventor of the present case has made earnest studies on this point and attempted to solve it. The problem to be solved by the present invention is to provide a circuit breaker capable of suppressing the storage space of the arc extinguishing device and miniaturizing it.

Means for Solving the Problems

[0007] To solve the above problems, a fixed contactor having a fixed contact, a movable contactor having a movable contact and capable of opening and closing the contact by its operation, and a hollow portion which is a penetrating hole, and gas flowing in from one opening of the hollow portion passes through the hollow portion and flows out from the other opening. An electrode cover provided on the movable contactor, and a circuit breaker in which gas can blow through the hollow portion when the movable contactor opens the contact.

[0008] Further, it is preferable that the other opening of the hollow portion is located at a position facing the fixed contact, and the area of the other opening is smaller than the area of one opening.

[0009] Further, it is preferable that the electrode cover can cover at least a part of the fixed contact in a state where the contact is closed.

[0010] Further, it is preferable that the electrode cover is configured to be able to generate an arc extinguishing gas by being heated by arc heat.

[0011] Further, the operation of the movable contactor for opening and closing the contact is a rotational operation, and at least a part of the inner wall forming the hollow portion of the electrode cover provided on the movable contactor is inclined with respect to the movable contactor, and the angle of the inclination is different between the side close to the rotation axis of the movable contactor and the side far from it. It is preferable to have a configuration.

Effects of the Invention

[0012] In the present invention, it is possible to provide a circuit breaker that can suppress the storage space of the arc extinguishing device and be miniaturized.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0014] The following shows embodiments for carrying out the invention. As can be understood from FIGS. 1 to 3, the circuit breaker 1 of the present embodiment includes a fixed contact 2 having a fixed contact point 21 and a movable contact 3 having a movable contact point 31, and the contacts can be opened and closed by the operation of the movable contact 3. An electrode cover 4 is provided on the movable contact 3, and the electrode cover 4 of the embodiment has a hollow portion 42 which is a through hole. This "through hole" refers to a hole through which gas flowing in from one opening of the hole can pass through the hole and flow out from the other opening. As can be understood from FIG. 4, the electrode cover 4 of the embodiment is attached to the movable contact 3 in a state where at least a part of the opening of the hollow portion 42 is not blocked. Therefore, as can be understood from FIG. 5, as the movable contact 3 moves away from the fixed contact point 21 to open the contact, air can blow through the hollow portion 42 to generate an air flow Fi toward the fixed contact point 21 side.

[0015] Incidentally, when the contact is opened, an arc A is generated between the contacts. However, the air flow Fi that has blown through the hollow portion 42 hits the arc A in a direction that makes its thickness thinner, so the cross-sectional area of the arc A can be reduced. In this specification, the cross-sectional area of the arc A refers to the area of a cross-section perpendicular to the direction in which the arc A extends. When the cross-sectional area of the arc A becomes smaller, the resistance value increases, making it difficult for current to flow and enabling the arc A to be extinguished. In this way, instead of a conventional arc extinguishing device, the arc A can be extinguished by the action of the electrode cover 4, so the storage space of the arc extinguishing device can be suppressed, and it is possible to provide a circuit breaker that can be miniaturized.

[0016] Next, the electrode cover 4 will be described in detail. The electrode cover 4 of the embodiment shown in FIGS. 1 to 5 has a cylindrical structure, and a hollow portion 42 is formed inside the side wall portion 41. In this example, the openings of the hollow portion 42 are provided on the tip side and the base end side of the electrode cover 4. As can be understood from FIGS. 3 and 4, in the electrode cover 4 of this embodiment, the base end side opening 421 faces the movable contact 3, the tip side opening 422 faces the fixed contact 21, and the movable contact 31 is attached to the movable contact 3 at a position where it fits into the hollow portion 42. At this time, since the base end side opening 421 and the tip side opening 422 are formed to have a size such that the openings are not blocked in the state of being attached to the movable contact 3, the hollow portion 42 penetrates around the movable contact 31 and air can blow through, resulting in a structure.

[0017] As can be understood from FIG. 5, when the movable contact 3 moves in a direction away from the fixed contact 21 to open the contact, an arc A is generated between the movable contact 31 and the fixed contact 21. In this embodiment, at this time, the air flow Fi passing through the inside of the electrode cover 4 is directed from the movable contact 31 side toward the fixed contact 21 side. In this way, by forming an air flow that suppresses the expansion of the cross-sectional area of the arc A around the arc A, it becomes possible to make it difficult for current to flow through the arc A and extinguish the arc A.

[0018] Further, in this embodiment, the area of the tip side opening 422 is formed smaller than the area of the base end side opening 421, and the cross-sectional area of the hollow portion 42 has a tapered shape that becomes smaller in the direction in which air flows. With such a configuration, the air flow Fi passing through the hollow portion 42 is guided by the inclination of the inner wall of the side wall portion 41 and blows toward the arc A, and the cross-sectional area of the arc A can be further reduced. Also, since the outlet side is narrower than the inlet side of the air, the speed of the air flow Fi becomes faster. When the flow velocity of the air flow Fi becomes faster, the pressure decreases and it becomes easier to entrain the surrounding air, so that the arc can be extinguished more efficiently. In this embodiment, the outer wall of the side wall portion 41 also has a tapered shape from the base end side toward the tip side.

[0019] Also, as can be understood from being shown in FIG. 6, it is preferable that the electrode cover 4 can cover at least a part of the fixed contact 21 when the contact is in a closed state. With such a structure, the tip of the electrode cover 4 can cover the periphery of the arc A generated when the contact is opened, and it is possible to restrict the cross-sectional area of the arc A from increasing. Further, if the electrode cover 4 can cover up to the fixed contact 21, air can be applied to the arc A from the time when the contacts are separated and the arc A starts to be generated, so that it becomes easier to reduce the area of the arc A earlier. Thereby, it becomes possible to improve the arc extinguishing performance.

[0020] Also, the electrode cover 4 is preferably configured to be able to generate an arc extinguishing gas when heated by arc heat. The electrode cover 4 of the embodiment is formed of a resin material that can be thermally decomposed by arc heat to generate an arc extinguishing gas. The electrode cover 4 may be formed of a material other than a resin material as long as it can generate an arc extinguishing gas. With such a configuration, the arc extinguishing gas generated from the electrode cover 4 can be blown onto the arc A by the air flow Fi, and it becomes possible to more effectively extinguish the arc A.

[0021] Also, in the case of the circuit breaker 1 in which the operation of the movable contact 3 that opens and closes the contact is a rotational operation, in the electrode cover 4, at least a part of the inner wall that forms the hollow portion 42 is inclined with respect to the movable contact 3 in the state provided on the movable contact 3, and it is preferable that the angle of the inclination is different between the side closer to the rotation axis of the movable contact 3 and the side farther from it. In the example shown in FIG. 7, a movable contact 31 is provided on the tip side of the movable contact 3, and a rotation axis (not shown) is provided on the opposite base end side. When the contact is opened in this example, the pivotally supported movable contact 3 rotates. Along with this rotational operation, there is a possibility that a difference in air volume occurs between the air flow Fi1 on the side farther from the rotation axis and the air flow Fi2 on the side closer to the rotation axis drawn into the hollow portion 42. For example, when the air volume of the air flow Fi2 on the side closer to the rotation axis decreases, if the inclination of the inner wall of the portion forming the semi-circle closer to the rotation axis among the side wall portions 41 of the electrode cover 4 is increased, the space into which the air flow Fi2 flows expands and the decrease in air volume can be suppressed. Thereby, it becomes possible to suppress the variation in air volume over the entire circumference of the arc A and make it easier to apply a sufficient amount of air, contributing to the improvement of the arc extinguishing performance.

[0022] Note that the inclination of the outer wall of the side wall portion 41 may be formed to be parallel to the inclination of the inner wall, or may be inclined at an angle different from the inclination angle of the inner wall. The outer wall of the side wall portion 41 in the example shown in FIG. 7 has a larger inclination in the portion forming the semi-circle closer to the rotation axis, similar to the inner wall.

[0023] Note that the electrode cover 4 having different inclination angles of the side wall portion 41 described above can also be configured to be separable between the side farther from the rotation axis and the side closer to it. As in the example shown in FIG. 8, if the side wall portion 41 of the electrode cover 4 is configured to be separable, it is easy to make the inclination angles of one side wall portion 41 and the other side wall portion 41 different, which is preferable.

[0024] As described above, the present invention has been explained by taking the embodiments as examples. However, the present invention is not limited to the above embodiments and can be implemented in various forms. For example, as can be understood from FIG. 9, the opening area of the tip-side opening 422 of the electrode cover 4 having the hollow portion 42 which is a penetrating hole can be formed larger than the opening area of the base-end side opening 421 to have a funnel-shaped configuration. In this embodiment, the outer wall of the side wall portion 41 is also formed such that the tip side is larger than the base-end side, similar to the inner wall. Note that the electrode cover 4 may be shaped to cover the fixed contact 21 in a state where the contact is closed.

[0025] When the electrode cover 4 of the example shown in FIG. 9 is provided in the circuit breaker 1, as can be understood from FIG. 10, when the movable contact 3 operates in the direction to open the contact, outside the electrode cover 4, an air flow Fo1 toward the fixed contact 21 is generated, and the air flow Fo1 becomes an air flow Fo2 that is drawn from the outside of the electrode cover 4 into the hollow portion 42. When the outer wall of the side wall portion 41 has a funnel-shaped configuration as in this example, the air flow Fo1 advances so as to spread outward along the inclination of the outer wall of the side wall portion 41, and the air flow Fo2 that has reached the tip side of the electrode cover 4 is easily drawn into the inside of the electrode cover 4. The air flow Fo2 drawn into the inside of the electrode cover 4 hits the arc A, and it becomes possible to extinguish the arc A by reducing the cross-sectional area of the arc A.

[0026] As described above, the present invention has been explained by taking the embodiments as examples. However, the present invention is not limited to the above embodiments and can be implemented in various forms. For example, although both the inner wall and the outer wall of the electrode cover 4 of the embodiment have a frustum of a cone shape, the inner wall or one or both of the outer walls may have a frustum of a pyramid shape which is a truncated pyramid shape.

Description of Reference Numerals

[0027] 1 Circuit breaker 2 Fixed contact 21 Fixed contact point 3 Movable contact 31 Movable contact point 4 Electrode cover 42 Hollow part

Claims

1. A fixed contactor having a fixed contact; A movable contactor having a movable contact and capable of opening and closing the contact by its operation; A side wall portion provided on the movable contact, The side wall portion moves when the movable contactor opens the contacts, thereby making it possible to blow air onto the arc that occurs when the contacts are opened.

2. The circuit breaker according to claim 1 , wherein at least a portion of the side wall portion is inclined with respect to the movable contact.

3. The circuit breaker according to claim 1 or 2, comprising a plurality of the side walls.

4. The circuit breaker according to claim 3 , wherein the side wall portions are flared or tapered from a base end side to a tip end side.

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