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

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[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 opening / closing operation of the handle or overcurrent, etc., the gas existing between them is broken down by the potential difference between the contacts and 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 is known to provide an arc extinguishing device or a magnet inside the circuit breaker to quickly extinguish the arc.

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

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] [[ID= 36]] [[ID= 37]]These conventional arc extinguishing methods using arc extinguishing devices or magnets increase the resistance value by extending the distance of the arc to make it difficult for current to flow and extinguish the arc. In the arc extinguishing method from the viewpoint of extending the distance of the arc like this, 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 magnetic force reduction due to heat.

Summary of the Invention

[0006] The inventors of this invention have attempted to solve this problem by diligently considering it. The problem that this invention aims to solve is to provide a circuit breaker that can be miniaturized by suppressing the housing space of the arc extinguishing device. [Means for solving the problem]

[0007] To solve the above problems, a circuit breaker is provided comprising a fixed contactor having a fixed contact, a movable contactor having a movable contact that can be opened and closed by its operation, and an electrode cover provided on the movable contactor having a hollow portion which is a through-hole, such that gas flowing in from one opening of the hollow portion passes through the hollow portion and flows out from the other opening, and the operation of the movable contactor to open the contacts allows gas to blow through the hollow portion.

[0008] Furthermore, it is preferable that the other opening of the hollow portion is located opposite the fixed contact point, and that the area of ​​the other opening is smaller than the area of ​​the other opening.

[0009] Furthermore, it is preferable that the electrode cover be configured to cover at least a portion of the fixed contact when the contact is closed.

[0010] Furthermore, it is preferable that the electrode cover be configured to generate arc-extinguishing gas when heated by arc heat.

[0011] Furthermore, it is preferable that the movable contact that opens and closes the contacts is a rotational motion, and that the electrode cover provided on the movable contact has at least a portion of the inner wall forming the hollow portion inclined with respect to the movable contact, and that the angle of inclination differs between the side closer to the pivot axis of the movable contact and the side further away from it. [Effects of the Invention]

[0012] The present invention makes it possible to provide a circuit breaker that can be miniaturized by suppressing the housing space for the arc extinguishing device. [Brief explanation of the drawing]

[0013] [Figure 1] This is a cross-sectional view showing the circuit breaker of the embodiment in a closed state. [Figure 2] This is a cross-sectional view showing the circuit breaker of the embodiment in an open state. [Figure 3] This is a perspective view of the movable contact and electrode cover of the embodiment. [Figure 4] This diagram shows the electrode cover of the embodiment attached to the movable contact. [Figure 5] This diagram illustrates the airflow around the electrode cover when the movable contact of the embodiment moves away from the fixed contact. The electrode cover is represented by a dashed line. [Figure 6] This figure shows the electrode cover of the embodiment covering at least a portion of the fixed contact when the contact is closed. However, the electrode cover is represented by a dashed line. [Figure 7] This diagram illustrates the airflow when the contacts open in a circuit breaker with a movable contact that has an electrode cover with different inclination angles on the side closer to and further from the pivot axis of the movable contact. The electrode cover is represented by a dashed line. [Figure 8] Figure 7 is a perspective view of the movable contact and the separable electrode cover in the embodiment shown. [Figure 9] In an embodiment different from the examples shown in Figures 1 to 8, this is a magnified view of the area around the electrode cover provided on the movable contact, which has a structure that widens towards the fixed contact. [Figure 10] Figure 9 shows the airflow when the contacts open in the embodiment shown. However, the electrode cover is represented by a dashed line. [Modes for carrying out the invention]

[0014] The following shows embodiments for implementing the invention. As can be understood from FIGS. 1 to 3, the circuit breaker 1 of this 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...

[0015] By the way, when the contacts are opened, an arc A occurs between the contacts. However, the air flow Fi that has passed 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. Thus, 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 becomes 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, the electrode cover 4 of this embodiment is oriented such that the base end side opening 421 faces the movable contact 3 and 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 when 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 where air can blow through.

[0017] As can be understood from FIG. 5, when the movable contact 3 moves away from the fixed contact 2 in the direction 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. Thus, 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 of air flow. 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 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] Furthermore, as can be seen from Figure 6, it is preferable that the electrode cover 4 can cover at least a portion of the fixed contact 21 when the contacts are closed. With such a structure, the tip of the electrode cover 4 can cover the periphery of the arc A generated when the contacts open, thereby restricting the increase in the cross-sectional area of ​​the arc A. Moreover, if the electrode cover 4 can cover the fixed contact 21, air can be applied to the arc A from the moment the contacts separate and the arc A begins to be generated, making it easier to reduce the area of ​​the arc A at an earlier stage. This makes it possible to improve arc extinguishing performance.

[0020] Furthermore, it is preferable that the electrode cover 4 be configured to generate arc-extinguishing gas when heated by the arc heat. In this embodiment, the electrode cover 4 is formed of a resin material capable of generating arc-extinguishing gas through thermal decomposition by the arc heat. The electrode cover 4 may be formed of any material other than resin, as long as it is capable of generating 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 airflow Fi, making it possible to extinguish the arc A more effectively.

[0021] Furthermore, in the case of a circuit breaker 1 in which the movable contact 3 that opens and closes the contacts is a rotational operation, it is preferable that at least a part of the inner wall of the electrode cover 4 that forms the hollow portion 42 when attached to the movable contact 3 is inclined with respect to the movable contact 3, and that the angle of inclination is different on the side closer to the rotation axis of the movable contact 3 and on the side further away. In the example shown in Figure 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. In this example, when the contact opens, the pivotally supported movable contact 3 rotates. As a result of this rotational operation, there is a risk that the amount of air drawn into the hollow portion 42 will differ between the airflow Fi1 on the side far from the rotation axis and the airflow Fi2 on the side closer to the rotation axis. For example, if the airflow Fi2 on the side closer to the pivot axis decreases, increasing the inclination of the inner wall of the semicircular portion of the side wall 41 of the electrode cover 4 closer to the pivot axis will widen the space into which the airflow Fi2 flows, thereby suppressing the decrease in airflow. This suppresses variations in airflow around the entire circumference of the arc A, making it easier to apply a sufficient amount of air and contributing to improved arc extinguishing performance.

[0022] 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 it may be inclined at a different angle from the inclination angle of the inner wall. In the example shown in Figure 7, the outer wall of the side wall portion 41, like the inner wall, has a larger inclination in the part that forms the semicircle closer to the pivot axis.

[0023] Furthermore, the electrode cover 4, which has different inclination angles for the side wall portions 41 as described above, can also be configured to be separable into a side farther from the pivot axis and a side closer to it. As shown in the example in Figure 8, if the side wall portions 41 of the electrode cover 4 are separable, it is easier to make the inclination angles of one side wall portion 41 different from those of the other side wall portion 41, which is preferable.

[0024] Although the present invention has been described above with reference to embodiments, the present invention is not limited to the above embodiments and can be made into various forms. For example, as can be seen from Figure 9, the electrode cover 4 having a hollow portion 42 which is a through hole can be made to have a flared shape by making the opening area of ​​the tip side opening 422 larger than the opening area of ​​the base side opening 421. In this embodiment, the outer wall of the side wall portion 41 is also formed so that the tip side is larger than the base side, similar to the inner wall. In addition, the electrode cover 4 may be shaped to cover the fixed contact 21 when the contacts are closed.

[0025] When the circuit breaker 1 is equipped with an electrode cover 4 as shown in Figure 9, as can be understood from Figure 10, when the movable contact 3 moves in the direction of opening the contacts, an airflow Fo1 is generated on the outside of the electrode cover 4 toward the fixed contact 21, and this airflow Fo1 becomes an airflow Fo2 that is drawn in from the outside of the electrode cover 4 toward the hollow portion 42. As in this example, when the outer wall of the side wall portion 41 has a flared shape, the airflow Fo1 moves outward along the slope of the outer wall of the side wall portion 41, and the airflow Fo2 that reaches the tip of the electrode cover 4 is easily drawn into the inside of the electrode cover 4. The airflow Fo2 drawn into the inside of the electrode cover 4 hits the arc A, and by reducing the cross-sectional area of ​​the arc A, it becomes possible to extinguish the arc A.

[0026] The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments and can be made into various forms. For example, although the inner and outer walls of the electrode cover 4 in the embodiment are both frustoconical in shape, one or both of the inner or outer walls may be truncated pyramidal in shape. [Explanation of Symbols]

[0027] 1 Circuit breaker 2 Fixed contact 21 Fixed contacts 3. Movable contact 31 Movable contact 4 Electrode Cover 42 Hollow section

Claims

1. A fixed contactor equipped with fixed contacts, A movable contactor equipped with a movable contact, which can open and close the contact by its movement, The movable contact comprises a side wall portion, The side wall portion is erected from the movable contact toward the fixed contact side, A circuit breaker in which the side wall portion moves as the movable contact opens the contacts, thereby generating an airflow between the contacts and blowing air onto the arc generated when the contacts are opened.

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

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

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

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