JP7512714B2 - Earthing switch - Google Patents

Description

The present invention relates to an earthing switch with a function for applying a short-circuit current.

Conventionally, in distribution boards and the like, earthing switches that have a stator and a movable element that can be connected and disconnected and that ground the main circuit are used (see Patent Document 1). In earthing switches, a short circuit may be performed in which the movable element is operated to close a circuit when a voltage is applied to a circuit to which the stator is connected. In Patent Document 1, the movable element is formed by a pair of rotatable blades, while the stator is provided with a contactor that contacts the blade while being sandwiched between the blade tips. A bolt is inserted through each blade, and a compression coil spring is loosely fitted into the bolt at the outer position of the blade to press the blade tip against the contactor.

Japanese Patent Application Laid-Open No. 8-153445

In Patent Document 1, when short-circuiting is performed, a large current is generated at the moment the movable element and the stator come into contact, causing the movable element and the stator to repel each other and separate. This causes problems with the earthing switch, such as a closing failure that makes it impossible to ground or causes an arc to progress.

To solve this problem, it is possible to increase the biasing force using the compression coil spring described above, but in this case, the operational load of closing the mover during normal operation (when the busbar is not energized) increases. This results in a problem that the closing time when short-circuiting is extended, and the time that the current is unstable and in a grounded state increases.

The present invention was made in consideration of these points, and aims to provide an earthing switch that can prevent the occurrence of closing failures and shorten the closing time when closing a short circuit.

The earthing switch of the present invention is an earthing switch comprising a stator and a movable member which are arranged to be capable of being brought into contact with and separated from each other, and which conduct electricity when in contact and cut off the flow of electricity when separated from each other, wherein the stator comprises a first region which the separated movable member first contacts when moving in a contact direction, and a second region which contacts when the movable member completes its movement in the contact direction , the movable member comprises a movable member main body which moves in a direction towards and away from the stator, and a plurality of conductive members fixed to the movable member main body and capable of contacting the stator , and comprises a movable contact portion which is not in contact with the first region when facing the first region, and which contacts the second region when facing the second region, and wherein the conductive members have a base connected to the movable member main body and are flexible enough to be deformed when in contact with the stator.

In addition, the earthing switch of the present invention is an earthing switch having a stator and a movable element that are arranged to be able to come into contact with and separate from each other, conducting electricity when in contact and cutting off the flow of electricity when separated from each other, wherein the movable element has a movable element main body that moves in a direction to come into contact with and separate from the stator, and a plurality of conductive members fixed to the movable element main body and capable of coming into contact with the stator, and the conductive members are formed by linear elements whose bases are connected to the movable element main body, and are arranged in a brush-like state with a plurality of closely packed conductive members, and are flexible enough to be deformed when in contact with the stator.
Furthermore, the earthing switch of the present invention is an earthing switch having a stator and a movable member that are arranged to be able to come into contact with and separate from each other, conducting electricity when in contact and cutting off the flow of electricity when separated, characterized in that the stator has a stator body and a plurality of conductive members fixed to the stator body and capable of contacting the movable member, and the conductive members are formed by linear bodies whose bases are connected to the stator body, are arranged in a brush-like state with multiple conductive members closely packed together, and have flexibility that allows them to deform when in contact with the movable member.

According to the present invention, when short-circuiting is performed, the flexible conductive members rub against the stator and the movable member and slide relative to each other, so that they can be contacted at multiple points. At this time, the multiple conductive members do not come completely apart from the stator and the movable member against which they slide, and at least a portion of them are in contact, so that the current-carrying state between them can be stably ensured. This makes it possible to prevent the occurrence of a closing failure due to an inability to ground or the progression of an arc. In addition, since the conductive members come into contact at multiple points, it is easier to maintain the contact between the stator and the movable member even if the contact pressure is reduced compared to the conventional structure in which the contact is at one point. This makes it possible to shorten the time required for short-circuiting and to transition to a grounded state with high current-carrying stability in a short time.

1 is a schematic perspective view of a state in which a mover in the earthing switch according to the first embodiment is in the process of moving; FIG. FIG. 2 is a schematic perspective view of the earthing switch according to the first embodiment in a closed state. FIG. 2 is a partially enlarged view of FIG. 1 is a partial front cross-sectional view of a mover and a stator when the mover is in the process of moving. FIG. FIG. 4 is a partial front cross-sectional view of a mover and a stator in a closed state. FIG. 5 is a schematic perspective view similar to FIG. 1 of a grounding switch according to a second embodiment.

[First embodiment]
Hereinafter, a grounding switch according to a first embodiment will be described with reference to the accompanying drawings. Fig. 1 is a schematic perspective view of a state in which a movable element in the grounding switch according to the first embodiment is in the process of moving. Fig. 2 is a schematic perspective view of the grounding switch according to the first embodiment in a closed state. Note that the grounding switch is not limited to the configuration shown in Figs. 1 and 2. The grounding switches shown in Figs. 1 and 2 are merely examples and can be modified as appropriate.

As shown in Figs. 1 and 2, the earthing switch 10 includes a movable element 12 and a stator 14 that can be brought into contact with and separated from each other. Three sets of movable elements 12 and stators 14 are provided for three phases, and in this embodiment, the three sets of movable elements 12 and stators 14 have roughly the same structure. The movable elements 12 and stators 14 are energized (closed circuit) when in contact (see Fig. 2), and are cut off (open circuit) when separated from each other. Here, in this embodiment, the earthing switch 10 is an air switch that cuts off current in the air (atmosphere), and is installed inside a switchboard or the like. In addition, in this embodiment, the earthing switch 10 is capable of short-circuiting to earth by changing from an open circuit state to a closed circuit state when a high voltage and high current are applied.

The earthing switch 10 comprises three insulators 16 provided at positions corresponding to the three sets of movable elements 12 and stators 14, and a base member 17 on which the three insulators 16 are erected. The earthing switch 10 further comprises a bracket-shaped support member 18 provided on the upper end side of the three insulators 16, and a rotational support part 19 provided on the base member 17 to rotatably support the movable element 12. The support member 18 is formed with a support wall 18a that supports the base end side of the stator 14.

The base member 17 is formed with a raised portion 17a so that the portion where the insulator 16 is installed is elevated. In addition, three upright walls 19a that form the rotation support portion 19 are formed in a line on the upper surface side of the base member 17, which is in front of the raised portion 17a. The rotation support portion 19 has three rotating walls 19b that are rotatably connected to the respective upright walls 19a, and the base end side of the movable element 12 is supported by the rotating walls 19b.

The mover 12 has a pair of blade members 12a made of a conductor such as copper, and the pair of blade members 12a constitute the mover body. The pair of blade members 12a are bent in a roughly crank shape so that the distance between the tip end is greater than the distance between the base end.

In the movable member 12, the pair of blade members 12a are also connected to the base end side by a connecting plate 12g and integrated. One of the pair of blade members 12a of the movable member 12 is connected to the rotating wall 19b, and the movable member 12 can move (rotate) in a direction toward and away from the stator 14. Specifically, the movable member 12 rotates from a state in which it is laid down in the horizontal direction, and the tip side rises along the trajectory of the rotation and approaches the tip side of the movable member 12 from the tip side of the stator 14 as shown in FIG. 1. Then, as the rotation progresses further, the tip side of the movable member 12 passes the tip side of the stator 14, and then the movable member 12 stands upright in the vertical direction as shown in FIG. 2 and comes into contact with the base side of the stator 14. In this state, the pair of blade members 12a are arranged to sandwich the stator 14.

The three movers 12 are connected at their base ends via a connection shaft 21 so that they rotate at the same timing and with the same rotation angle. The connection shaft 21 is made of a conductor such as copper, and is electrically connected to the three movers 12. The connection shaft 21 is grounded via wiring or the like (not shown), and the movers 12 are set to ground potential.

The stator 14 has a flat connection portion 14a and a sliding contact portion 14b that is connected to the underside of the connection portion 14a and contacts the mover 12. The tip side of the connection portion 14a protrudes beyond the sliding contact portion 14b, and this protruding portion is connected to a circuit, bus bar, etc. (not shown).

The sliding contact portion 14b has a shape that extends in a linear direction along the rotation direction of the tip of the mover 12. The sliding contact portion 14b has a shape in which the portion that comes into contact with the mover 12 bulges out in a roughly semi-cylindrical shape. The sliding contact portion 14b of the stator 14 is formed with a first region 14A that forms the tip side, and a second region 14B that forms a predetermined region from the base end side other than the first region 14A.

Figure 3 is a partial enlarged view of Figure 1. As shown in Figure 3, the first region 14A is the region that first comes into contact when the mover 12, separated from the stator 14, moves (rotates) in a contact direction in which it approaches and comes into contact with the stator 14. The second region 14B is adjacent to the first region 14A in the contact direction, and is the region that comes into contact after the mover 12 comes into contact with the first region 14A as the mover 12 moves in the contact direction, and is the region that the mover 12 comes into contact with when the movement is completed. The second region 14B is the region where current flows between the mover 12 and the stator 14 in the normal closed circuit state.

At the sliding contact portion 14b of the stator 14, both the first region 14A and the second region 14B are formed in a shape that bulges out roughly like a semi-cylindrical cylinder, but their sizes (formation regions) are different. Specifically, the second region 14B is formed smaller than the first region 14A in both the vertical direction and the horizontal direction (the direction in which the stator 14 is sandwiched between the pair of blade members 12a).

The tip sides of the pair of blade members 12a in the mover 12 are bulged in the direction in which they approach each other, and these bulged parts form the movable contact parts 12b that come into contact with the stator 14. The movable contact parts 12b are formed at the center position in the rotation direction of the tip of the mover 12 on the tip side of the pair of blade members 12a.

The movable member 12 is equipped with a pressure spring (elastic member) 12c made of a compression coil spring. The pressure spring 12c applies an elastic force to the pair of blade members 12a in a direction that brings them closer to each other, and acts as a brake against the pair of blade members 12a moving away from each other.

Specifically, the pressure spring 12c is provided on the outer surface side of one of the pair of blade members 12a, and is inserted into a bolt 12d that passes through the pair of blade members 12a. A nut 12e (see FIG. 4, not shown in FIG. 3) is screwed onto the tip side of the bolt 12d, and the pressure spring 12c is disposed in a compressed state between the head of the bolt 12d and the outer surface of the blade member 12a. A connecting tube 12f is also interposed between the inner surfaces of the tip sides of the pair of blade members 12a, and the bolt 12d is inserted into the connecting tube 12f. The positional relationship between the head of the bolt 12d and the nut 12e may be reversed.

The movable member 12 has a plurality of conductive members 20 in the vicinity of the movable contact portion 12b. Specifically, the conductive members 20 are provided on the inner surface side of the tip of the pair of blade members 12a, adjacent to both sides of the movable contact portion 12b in the rotation direction of the movable member 12.

The conductive member 20 is made of a linear body such as a copper wire, and has flexibility that allows it to deform when it comes into contact with the stator 14. The base of the conductive member 20 is fixed to and electrically connected to the blade member 12a. Therefore, when the conductive member 20 comes into contact with the sliding contact portion 14b of the stator 14, a current flows from the sliding contact portion 14b through the conductive member 20 to the blade member 12a.

The conductive members 20 are arranged in a brush-like shape with multiple pieces closely spaced apart. When the pair of blade members 12a extend linearly in the direction sandwiching the stator 14, the conductive members 20 are formed longer than the protruding amount of the movable contact portion 12b.

Here, the positional relationship between the movable contact portion 12b, the conductive member 20, and the sliding contact portion 14b of the stator 14 will be described. FIG. 4 is a partial front cross-sectional view of the movable member and the stator when the movable member is in the process of moving. As shown in FIG. 4, when the movable member 12 faces the first region 14A of the sliding contact portion 14b, the conductive member 20 in the vertical center in FIG. 4 abuts against the sliding contact portion 14b, and is pushed by the sliding contact portion 14b and deforms so as to collapse or bend. Thus, the conductive member 20 is pressed against the outer surface of the first region 14A, and the contact state is maintained and electrically conductive. In this state, the movable contact portion 12b is separated from the first region 14A and is not in contact with it, and no current flows between them.

Figure 5 is a partial front cross-sectional view of the movable member and the stator in a closed state. When the movable member 12 is further rotated and faces the second region 14B of the sliding contact portion 14b, as shown in Figure 5, the movable contact portion 12b comes into contact with the second region 14B. At this time, the conductive member 20 is further pressed by the sliding contact portion 14b and deformed, and the conductive member 20 is pressed against the outer surface of the second region 14B. Therefore, the contact state between both the movable contact portion 12b and the conductive member 20 is maintained with respect to the sliding contact portion 14b, and an electrically conductive state is established.

In this way, the movable contact portion 12b does not contact the first region 14A but contacts the second region 14B, whereas the conductive member 20 is arranged so as to be able to contact both the first region 14A and the second region 14B.

Next, the short-circuiting operation of the earthing switch 10 will be described. When performing maintenance on the switchboard in which the earthing switch 10 is installed in an open state, the movable member 12 is moved in a contact direction to contact the stator 14 via a drive mechanism (not shown). At this time, the movable member 12 is separated from the stator 14 to cut off the current flow, and the tip side of the movable member 12 first contacts the first region 14A of the sliding contact portion 14b of the stator 14 as shown in FIG. 1. Just before this contact, a reverse current is generated between the first region 14A of the sliding contact portion 14b and the movable member 12, and this reverse current generates a repulsive force in a direction in which the movable member 12 moves away from the stator 14.

In this embodiment, in the initial stage of contact between the first region 14A of the sliding contact portion 14b and the movable member 12, multiple flexible conductive members 20 rub and slide against the first region 14A, and can be brought into contact at multiple points. With such contact at multiple points, even if some of the multiple conductive members 20 deviate from the first region 14A, the other conductive members 20 can maintain contact and ensure electrical continuity between the conductive members 20 and the sliding contact portion 14b. This can prevent grounding failure and arcing between the stator 14 and the movable member 12, and can avoid the occurrence of closing failures.

In addition, because the conductive member 20 is a linear body, the diameter of the portion that contacts the stator 14 can be made sufficiently small, and thus the electromagnetic repulsive force acting on the conductive member 20 due to the generation of a reverse current can be reduced. This also contributes to maintaining contact between the conductive member 20 and the first region 14A of the sliding contact portion 14b, and makes it possible to better prevent the occurrence of closing failures.

To prevent arcing between the stator 14 and the mover 12, a conventional structure has been adopted in which the elastic force of the contact pressure spring 12c is strengthened to increase the contact pressure between the mover and the stator without using the conductive member 20 of this embodiment. However, in this conventional structure, friction increases when the mover slides against the stator, so it was necessary to increase the force of the mover to shorten the closing time. This resulted in a problem of larger and more expensive closing mechanism, as well as the mover bouncing and arcing due to the impact when the mover first comes into contact with the stator.

In this respect, in the present embodiment, the movable member 12 is provided with multiple conductive members 20, and contact with the stator 14 is made at multiple points. This makes it easier to maintain contact between the stator 14 and the movable member 12 and prevents arcing, even if the contact pressure between the stator 14 and the movable member 12 is reduced without increasing the elastic force of the contact pressure spring 12c compared to the conventional structure. This allows the closing mechanism to be made smaller and less expensive, while shortening the closing time when short-circuiting is made, and allows the device to transition to a grounded state with high current stability in a short time.

In addition, during the current flow to the ground as shown in FIG. 2, the second region 14B of the sliding portion 14b and the movable contact portion 12b of the movable member 12 come into contact and conduct current, so that the heat capacity of these can be increased, and welding due to melting of the contacts can be avoided even if a large current flows for several seconds during a short circuit. In this case, too, the current is diverted from the second region 14B to multiple conductive members 20, and the current between the second region 14B, which is the main contact, and the movable contact portion 12b can be reduced to suppress heat generation.

Furthermore, during the energization of the ground as shown in FIG. 2, an electromagnetic attraction force acts in the contraction direction so that the multiple conductive members 20 cover the second region 14B of the sliding contact portion 14b, and it is expected that an electromagnetic attraction force greater than the electromagnetic repulsion force due to the concentrated current will be generated, thereby improving the adhesion between them.

In addition, since the multiple conductive members 20 are brush-shaped, it is possible to ensure a wide contact area with the first region 14A and the second region 14B of the sliding contact portion 14b.

[Second embodiment]
Next, a second embodiment of the present invention will be described with reference to Fig. 6. In the following description, the same reference numerals may be used for components that are the same as or equivalent to those in the first embodiment, and descriptions thereof may be omitted or simplified.

Figure 6 is a schematic perspective view similar to Figure 1 of a grounding switch according to a second embodiment. As shown in Figure 6, in the second embodiment, a plurality of conductive members 30 are provided on the sliding contact portion 14b of the stator 14. Here, the sliding contact portion 14b is the stator body.

The conductive member 30, like the conductive member 20 in the first embodiment, is made of a linear body such as a copper wire, and has flexibility that allows it to deform when it comes into contact with the movable member 12. The base of the conductive member 20 is fixed to and electrically connected to the sliding contact portion 14b. When the conductive member 30 comes into contact with the tip side of the blade member 12a of the movable member 12, a current flows between them.

The conductive member 30 is formed continuously across the first region 14A and the second region 14B of the sliding contact portion 14b. The conductive member 30 is provided in a brush shape, and is formed so that the pair of blade members 12a protrude linearly in parallel to the direction in which the stator 14 is sandwiched.

The sliding contact portion 14b is formed to have different sizes in the first region 14A and the second region 14B, as in the first embodiment. Therefore, although the tip positions of the conductive members 30 are located in approximately the same vertical plane, the length of each conductive member 30 differs according to the shape of the sliding contact portion 14b, which bulges into a roughly semi-cylindrical shape.

In the second embodiment, the conductive member 30 of the stator 14 and the movable member 12 can be brought into contact at multiple points during the initial stage of short-circuiting. This makes it possible to prevent arcing between the stator 14 and the movable member 12, and to avoid the occurrence of closing failures, thereby achieving the same effects and advantages as the first embodiment.

The present invention is not limited to the above-described embodiments, and can be modified in various ways. In the above-described embodiments, the size, shape, orientation, etc. shown in the attached drawings are not limited to these, and can be modified as appropriate within the scope of the effects of the present invention. In addition, the present invention can be modified as appropriate without departing from the scope of the purpose of the present invention.

The structure and orientation of the mover 12 and stator 14 can be modified in various ways as long as they have the same functions as those described above. For example, the mover 12 can be moved in a linear direction to be detachable from the stator 14, depending on the installation space and current carrying capacity of the earthing switch 10.

In addition, although the above description has been given of the case where the earthing switch 10 is an air switch, this does not preclude the switch being one in which the movable element 12 and the stator 14 open and close in an insulating gas (arc-extinguishing gas) or vacuum environment.

In addition to being linear, the conductive members 20, 30 may be flexible strips that can be elastically deformed by the movement of the movable member 12. In this case, forming the tip of the strip into a tapered shape is advantageous in that the contact diameter of the conductive members 20, 30 can be made sufficiently small to suppress the electromagnetic repulsive force.

10 Earthing switch 12 Movable element 12a Blade member (Movable element main body)
12b Movable contact portion 14 Stator 14A First region 14B Second region 14b Sliding portion (stator body)
20 Conductive member 30 Conductive member

Claims (6)

A grounding switch having a stator and a movable element that are provided so as to be capable of contacting and separating, and that conduct electricity when in contact and cut off electricity when separated,
the stator includes a first region with which the movable element first comes into contact when the movable element moves in a contact direction from a spaced apart state, and a second region with which the movable element comes into contact when the movable element completes moving in the contact direction;
the movable element includes a movable element body that moves in a direction toward and away from the stator, and a plurality of conductive members that are fixed to the movable element body and can contact the stator, and includes a movable contact portion that is out of contact with the first region when facing the first region and that is in contact with the second region when facing the second region,
The conductive member has a base connected to the movable body and has flexibility such that it can be deformed by contact with the stator. 2. The earthing switch according to claim 1 , wherein the conductive member is provided so as to be able to come into contact with both the first region and the second region. 3. The earthing switch according to claim 1, wherein the conductive member is formed of a linear body or a tapered strip. 4. The earthing switch according to claim 1, wherein the conductive member is provided in a brush shape. A grounding switch having a stator and a movable element that are provided so as to be capable of contacting and separating, and that conduct electricity when in contact and cut off electricity when separated,
the mover includes a mover body that moves in a direction toward and away from the stator, and a plurality of conductive members that are fixed to the mover body and can come into contact with the stator;
The conductive member is formed by a linear body whose base is connected to the movable body, and is arranged in a brush-like shape with multiple linear members closely spaced apart , and is flexible enough to be deformed when in contact with the stator. A grounding switch having a stator and a movable element that are provided so as to be capable of contacting and separating, and that conduct electricity when in contact and cut off electricity when separated,
the stator includes a stator body and a plurality of conductive members fixed to the stator body and capable of contacting the movable element;
The conductive member is formed by a linear body whose base is connected to the stator body, and is arranged in a brush-like shape with multiple linear members closely spaced apart , and is flexible enough to be deformed when in contact with the movable member.

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