CN111758142A

CN111758142A - Switch with a switch body

Info

Publication number: CN111758142A
Application number: CN201880090115.0A
Authority: CN
Inventors: 细野乔文; 佐藤深大; 冈野拓哉; 宍户正典; 白井宽之; 西町诚一郎
Original assignee: Hitachi Industrial Equipment Systems Co Ltd
Current assignee: Hitachi Industrial Equipment Systems Co Ltd
Priority date: 2018-03-06
Filing date: 2018-12-19
Publication date: 2020-10-09
Anticipated expiration: 2038-12-19
Also published as: WO2019171707A1; JP6953329B2; CN111758142B; JP2019153532A

Abstract

The invention aims to provide a circuit breaker which can alleviate the electric field of a fixed contact without arranging a shielding piece molded by resin and realize a smaller size compared with the prior art. In order to solve the above problem, a circuit breaker according to the present invention includes a movable contact and a fixed contact, the fixed contact having a bifurcated portion, and a movable conductor having a width substantially equal to a gap between the bifurcated portion is disposed on a front end side of the bifurcated portion when the movable contact is off, and the movable conductor sandwiches the front end side of the movable contact when the movable contact is on.

Description

Switch with a switch body

Technical Field

The present invention relates to a circuit breaker incorporated in a switchgear such as a switchgear, and more particularly to a circuit breaker capable of shortening an insulation distance as compared with the conventional art.

Background

A switching device such as a switching mechanism is configured by electrically connecting various switches such as a Circuit Breaker (CB), a circuit breaker (DS), and an Earthing Switch (ES). Since the breaker built in the switchgear is switched without load when the circuit breaker is in the on state, the off/on speed is only low, and the circuit breaker and the ground switch are combined by sharing the operator, thereby realizing miniaturization of the switchgear as a whole.

In particular, although the knife type common to the movable portions of the circuit breaker and the earthing switch is suitable for miniaturization, it is necessary to have a large insulation distance in order to cope with a high electric field caused by electric field concentration at the stator end portion of the circuit breaker, and as a result, there is a problem that the switchgear incorporating the circuit breaker becomes large in size.

In order to solve this problem, patent document 1 discloses "a high-voltage switching device having a switch including: a movable side conductor 2 connected to one bus conductor; a movable portion 4 comprising a conductor member having one end rotatably supported by the movable side conductor 2 and provided in 1 for each phase; and an insulating gas, wherein the switch used in the high-voltage switchgear includes

shields

7a, 7b formed by molding surfaces of shield electrodes 10c, 10d electrically and mechanically fixed to the movable-side conductor 2 using an insulating coating or an insulator, and the

shields

7a, 7b are disposed so as to face side surfaces of the movable part 4 at an off position of the movable part 4. As described above, by disposing a shield molded from an insulating material such as resin at the end of the stator of the circuit breaker, the electric field is relaxed, the insulation distance is shortened, and the entire switchgear is miniaturized.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2012 and 15009.

Disclosure of Invention

Problems to be solved by the invention

However, the switch of patent document 1 requires a molded shield for relaxing the electric field, which not only increases the size of the switch itself, but also requires a mold and injection molding equipment, and therefore, there is a large room for improvement in terms of both man-hours and cost.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a circuit breaker that can mitigate an electric field at an end portion of a stator with a simple structure, and that can contribute to both improvement in manufacturing man-hours and manufacturing cost and miniaturization.

Means for solving the problems

In order to achieve the above object, a circuit breaker according to the present invention includes a switch including a movable contact and a fixed contact, the fixed contact having a bifurcated portion, and a movable conductor having a width substantially equal to a gap between the bifurcated portion and the fixed contact is disposed on a front end side of the bifurcated portion when the movable contact is off, and the movable conductor sandwiches the front end side of the movable contact when the movable contact is on.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a circuit breaker that is smaller than the conventional circuit breaker by relaxing the electric field of the fixed contact and improving the withstand voltage performance.

Drawings

Fig. 1 is a perspective view showing a schematic configuration of a circuit breaker according to embodiment 1.

Fig. 2 is a schematic diagram showing an electric field in the vicinity of a bifurcated portion of the fixed contact.

Fig. 3A is a plan view of a breaking position used in the circuit breaker of embodiment 1.

Fig. 3B is a sectional view a-a of the open position used in the circuit breaker of embodiment 1.

Fig. 4A is a plan view of the on position used in the circuit breaker of embodiment 1.

Fig. 4B is a sectional view a-a of the on position used in the circuit breaker of embodiment 1.

Fig. 5 is a sectional view of a breaking position used in the circuit breaker of embodiment 2.

Fig. 6 is a sectional view of the on position used in the circuit breaker of embodiment 2.

Detailed Description

Hereinafter, the circuit breaker 100 of the present invention will be described based on the illustrated embodiment. In the drawings, the same reference numerals are used for the same components.

Example 1

A detailed configuration of a circuit breaker according to embodiment 1 incorporated in a switchgear such as a switchgear will be described with reference to fig. 1 to 4B.

Fig. 1 is a perspective view showing a schematic configuration of a circuit breaker 100 according to embodiment 1. Here, only the inter-pole portion of the circuit breaker 100 is shown, and illustration is omitted for a known technique related to a switching device such as a fixed side of an oscillation circuit and a ground switch and a drive system of an insulating rod.

The circuit breaker 100 of the present embodiment is a knife circuit breaker including a fixed contact 1 made of metal and a movable contact 2 having a metal knife structure, and the movable contact 2 is rotated to position the tip of the movable contact 2 in the closed position by being sandwiched between the gaps of the two-pronged portions of the fixed contact 1. In addition, a movable conductor 3 made of metal having a width substantially equal to that of the gap is provided in the gap between the bifurcated portions of the fixed contact 1 so as to be movable up and down.

Here, the electric field in the vicinity of the bifurcated portion of the fixed contact 1 during disconnection is described as a case where the movable conductor 3 is not arranged in the gap between the bifurcated portions and a case where the movable conductor is arranged, using the plan view of fig. 2.

Fig. 2 (a) is a diagram showing an outline of an electric field in a case where the movable conductor 3 is not arranged. In this case, the equipotential lines enter the inside of the bifurcated portion of the fixed contact 1, and as a result, the equipotential lines are particularly closely spaced at the corner portion on the tip side of the bifurcated portion, and an electric field concentration occurs. This increases the possibility of discharge from the tip of the fixed contact 1, and therefore, it is necessary to avoid discharge by increasing the insulation distance on the tip side of the fixed contact 1. That is, it is necessary to increase the size of the case of the switchgear and the like, and to secure a sufficient insulation distance around the fixed contact 1, and therefore it is difficult to miniaturize the switchgear as a whole.

In contrast, fig. 2(b) is a diagram showing an outline of an electric field in a case where the movable conductor 3 is arranged. As shown in this figure, when the movable conductor 3 having the same potential as that of the fixed contact 1 is provided in the gap between the bifurcated portions of the fixed contact 1, the equipotential line does not enter the inside of the bifurcated portions of the fixed contact 1, and the electric field at the tip end portion thereof can be relaxed to suppress the possibility of discharge, so that the insulation distance can be shortened as compared with fig. 2 (a). That is, since the insulation distance can be shortened, discharge can be avoided even if the case of the switchgear is made smaller, and the entire switchgear can be easily downsized.

Next, the structure of the circuit breaker 100 of the present embodiment will be described in more detail with reference to fig. 3A to 4B.

Fig. 3A and 3B are a plan view and a sectional view of the circuit breaker 100 in the breaking position, respectively.

Fig. 3A is a plan view of the circuit breaker 100 installed in the case 4 of the switchgear with a predetermined insulation distance secured, and shows a state in which the movable contactor 2 in the breaking position is supported by the support member 9.

Fig. 3B is a sectional view taken along line a-a of fig. 3A, and shows a structure in which the movable contact 2 can rotate about a rotary shaft 8 provided at one end of the movable contact 2, and a structure in which the spring 5 and the insulator 6 are disposed below the movable conductor 3. According to this structure: the movable conductor 3 is urged upward by the spring 5, but since the stopper 7a protruding from the fixed contact 1 defines the upper limit of movement of the movable conductor 3, the height of the upper surface 1a of the bifurcated portion of the fixed contact 1 and the height of the upper surface of the movable conductor 3 substantially coincide with each other when the circuit breaker 100 is in the open state. Further, a guide mechanism 7b for guiding the vertical movement of the movable conductor 3 is also provided on the inner surface of the bifurcated portion of the fixed contact 1, and the position of the front surface 1b of the bifurcated portion of the fixed contact 1 substantially coincides with the position of the front surface of the movable conductor 3.

Thus, when the movable contact 2 is opened and the circuit breaker 100 is at the breaking position, the movable conductor 3, which is at the same potential as the fixed contact 1 by the stopper 7a or the guide mechanism 7b, is jammed between the bifurcated portions of the fixed contact 1. That is, the structure of fig. 2(b) can reduce the electric field at the corner of the fixed contact 1 and suppress the discharge, and thus the insulation distance to the case 4 can be shortened.

On the other hand, fig. 4A and 4B are a plan view and a cross-sectional view of the circuit breaker 100 in the on position, respectively.

Fig. 4A is a plan view of the circuit breaker 100, showing a state in which the tip of the movable contact 2 is clamped between the bifurcated portions of the fixed contact 1 and is closed.

Fig. 4B is a sectional view a-a of fig. 4A, showing that when the movable contactor 2 is turned on to be in the on position, the spring 5 is compressed to sink the movable conductor 3 downward. Further, since the insulator 6 is disposed below the spring 5, even when the breaker 100 is energized, no current flows through the spring 5, and heat generation in the spring 5 does not occur. Further, although a metal spring is illustrated as an example of the spring 5 disposed below the movable conductor 3, any component other than the metal spring 5, for example, a resin spring, an elastic body such as rubber, or the like may be used as long as it is a component having elasticity.

According to the present embodiment described above, the simple configuration in which the metal movable conductor is disposed in the gap between the bifurcated portions of the fixed contact can alleviate the electric field at the corner of the bifurcated portion of the fixed contact when the breaker is at the open position, suppress the discharge, and shorten the insulation distance. As a result, the withstand voltage performance of the circuit breaker can be improved, and the circuit breaker can be improved in both the manufacturing man-hour and the manufacturing cost and can be miniaturized. Further, by using the circuit breaker, miniaturization can be achieved as the entire switchgear.

Example 2

Next, a circuit breaker 100 according to embodiment 2 will be described with reference to fig. 5 and 6. Note that, the same points as in example 1 will not be described repeatedly. In addition, the structure using the rotating movable contact 2 in embodiment 1, and the structure using the linearly moving movable contact 2 in embodiment 2.

Fig. 5 and 6 are a cross-sectional view of the circuit breaker 100 in a tripped position and a top view of the circuit breaker 100 in an on position, respectively.

As shown in fig. 5, the fixed contact 1 has a two-pronged structure at its tip end, and the movable conductor 3 is disposed therebetween, as in embodiment 1. Further, a spring 5 is disposed on the back side of the movable conductor 3. In the present embodiment, the movable conductor 3 is biased by the spring 5, but the position of the front surface 1b of the bifurcated portion is made to substantially coincide with the position of the front surface of the movable conductor 3 at the time of disconnection by a stopper or the like.

At this time, since the relaxed electric field as described in fig. 2(b) is formed, the effect of shortening the insulation distance can be obtained also in the configuration of the present embodiment, as in embodiment 1.

Further, as shown in fig. 6, when the movable contact 2 linearly moves to the on position, the spring 5 is compressed and the movable conductor 3 moves to the fixed side, but the movement in the height direction of the movable contact 2 does not occur, so that it is not necessary to secure a space above the circuit breaker 100 unlike the configuration of fig. 3B of embodiment 1. That is, in the switchgear using the circuit breaker of embodiment 1, since a sufficient turning space needs to be secured above the circuit breaker, the switchgear becomes large in the height direction, and in contrast to this, in the switchgear using the circuit breaker of this embodiment, since a turning space above the circuit breaker is not needed, the switchgear can be further miniaturized.

Description of reference numerals

100 … circuit breaker, 1 … fixed contact, 1a … upper surface, 1b … front surface, 2 … movable contact, 3 … movable conductor, 4 … box, 5 … spring, 6 … insulator, 7a … limiter, 7b … guide mechanism, 8 … rotating shaft, 9 … support component.

Claims

1. A switch comprising a movable contact and a fixed contact, characterized in that:

the fixed contact has a bifurcated portion that is,

a movable conductor having a width substantially equal to the gap between the bifurcated portions is disposed on the distal end side of the bifurcated portion when the movable contact is off, and the distal end side of the movable contact is sandwiched between the distal end sides of the bifurcated portions when the movable contact is on.

2. The switch of claim 1, wherein:

when the movable contact is opened,

the movable conductor is at substantially the same potential as the fixed contact, and,

the upper surface of the movable conductor is substantially coincident with the height of the upper surface of the bifurcated portion of the fixed contact,

the front surface of the movable conductor substantially coincides with the position of the front surface of the bifurcated portion of the fixed contact.

3. The switch of claim 2, wherein:

an elastic body for urging the movable conductor toward the upper surface side or the front surface side of the bifurcated portion,

the movable contact moves the movable conductor while compressing the elastic body when the movable contact is connected.

4. The switch of claim 3, wherein:

the movable contact is turned off or turned on by a rotational motion or a linear motion.

5. A switch that breaks an electric circuit by separating a movable contact from a fixed contact, characterized in that:

the front end of the fixed contact piece is a double-fork metal piece,

the movable conductor disposed between the bifurcated metal members is pressed by the movable contact member and moves.

6. The switch of claim 5, wherein:

when the circuit is broken, the movable conductor is used to plug the metal pieces at the front end of the fixed contact,

the surface of the movable conductor is at the same potential as the fixed contact.

7. The switch of claim 6, wherein:

an elastic body is provided on a back side of the movable conductor, and,

an insulator is disposed on a back side of the elastic body.

8. The switch of claim 7, wherein:

a restricting member that restricts a moving range of the movable conductor is provided to the fixed contactor,

the restricting member prevents the movable conductor from protruding from the metal piece at the front end of the fixed contact when the circuit is broken.