JP2016076293A - Circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit breaker that can prevent stagnation on a grid of arc drawn from an arc entrance of an arc extinguishing device, and move the arc to a gas exit side of the arc extinguishing device in short time, thereby surely performing arc parting and arc cooling by the grid.SOLUTION: An arc extinguishing device 11 for extinguishing arc occurring between a fixed contact and a movable contact comprises plural grids 13 which are located at an arc entrance 15 side at one ends of the grids and at a gas exit 16 side at the other ends of the grids and arranged in a layer form so as to be spaced from one another through gaps. The grid has a pair of arc driving plates 17, 18 formed of magnetic material, and a resin plate 19 laminated between the pair of arc driving plates. An arc cut-out groove 20 is formed at the end portion of the arc entrance side. A gas blow-out unit 21 for blowing out vaporized gas occurring due to melting of the resin plate as ablation gas directing from the arc entrance side to the gas exit side is formed in the pair of arc driving plates.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a circuit breaker for wiring breakers, earth leakage breakers and the like.

A circuit breaker such as a circuit breaker for wiring or a circuit breaker is used in order to cut off a short circuit current flowing in the load current or an overcurrent of the overload current (for example, Patent Document 1).
The circuit breaker disclosed in Patent Document 1 includes a fixed contact provided with a fixed contact, a movable contact provided with a movable contact capable of contacting the fixed contact, a fixed contact and a movable contact during opening operation. And an arc extinguishing device for retracting and extinguishing an arc generated between the two. The arc-extinguishing device includes a pair of side plates made of electrical insulators arranged in parallel to each other, and a plurality of plate-like grids made of a magnetic material fixed in layers between the pair of side plates. An arc notch groove (referred to as a notch groove in Patent Document 1) is formed at the end of the drawing side (inlet side).

  And the arc generated between the fixed contact and the movable contact during the opening operation is driven toward the entrance of the arc extinguishing device by the action of electromagnetic force, and due to the bias of the magnetic flux distribution passing through the grid by the magnetic field of the arc current, It is drawn into the arc notch groove formed at the end of the grid. The arc drawn to the bottom of the arc notch groove of the grid is transferred to the grid plate surface and driven toward the exit of the arc extinguishing device on the opposite side to the arc entrance side, so that multiple grids are formed. It is divided and the voltage drop increases, and a cooling action by melting of the grid is added. As a result, the arc voltage increases, the arc between the fixed contact and the movable contact disappears, and the short-circuit current (or overcurrent) is current-limited.

JP 2012-199000 A

By the way, the circuit breaker of patent document 1 does not act on the arc drawn to the bottom of the arc notch groove of the grid, and the drive toward the exit of the arc extinguishing device due to the deviation of the magnetic flux distribution passing through the grid does not act. The arc located at the bottom of the arc groove is driven to the outlet side of the arc extinguishing device by the arc gas flowing from the inlet side toward the outlet.
However, since the flow of the arc gas is weak as a force for moving the arc to the exit side of the arc extinguishing device, the arc concentrates on the bottom of the arc notch groove of the grid, and the bottom of the arc notch groove melts. There is a risk of returning to the arc of the book.

  Accordingly, the present invention has been made in view of the above circumstances, and prevents the stagnation of the arc drawn from the arc inlet of the arc extinguishing device on the grid and moves the arc to the gas outlet side of the arc extinguishing device in a short time. An object of the present invention is to provide a circuit breaker that reliably performs arc division and arc cooling by a grid.

  In order to achieve the above object, a circuit breaker according to one aspect of the present invention includes a fixed contact having a fixed contact in a main body case, a movable contact having a movable contact contacting and separating from the fixed contact, An arc extinguishing device that extinguishes an arc generated between the fixed contact and the movable contact; and the arc extinguishing device has one end on the arc entrance side near the fixed contact and the movable contact. A plurality of grids, the other end of which is located on the gas outlet side, are arranged in layers with a gap between each other, the plurality of grids including a pair of arc drive plates made of a magnetic material, and these A pair of arc drive plates, and a pair of arc drive plates, and an arc notch groove is formed at the arc entrance side end of the pair of arc drive plates and the resin plate, the pair of arc drive plates, Generated by melting the resin plate The was evaporated gas as the gas blowout unit that blows as ablation gas toward the gas outlet side is formed from the arc inlet side.

  According to the circuit breaker according to the present invention, the arc generated between the fixed contact and the movable contact and drawn into the arc notch groove of the grid melts the resin plate constituting the grid to evaporate the gas. Is generated. The evaporating gas is blown out as ablation gas from the gas blowing portion formed in the pair of arc drive plates toward the gas outlet side from the arc inlet side, and the arc moves toward the gas outlet by the blowing action of the ablation gas. As a result, the arc generated between the fixed contact and the movable contact does not stagnate on the grid, and is divided into a plurality of grids in a short time and the cooling action is performed, so that the arc can be extinguished efficiently. it can.

It is sectional drawing which shows the principal part of the circuit breaker of 1st Embodiment which concerns on this invention. It is a perspective view which shows the arc-extinguishing apparatus arrange | positioned inside the circuit breaker of 1st Embodiment. It is a perspective view which shows the structure of the grid which comprises an arc-extinguishing apparatus. It is a side view which shows the structure of a grid. It is the figure which showed the state which ablation gas generate | occur | produces when an arc contacts a grid.

DESCRIPTION OF EMBODIMENTS Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a main part of a circuit breaker 1 according to a first embodiment, and is illustrated by a fixed contact 4 fixed to the case 2 and a handle 5 in an insulating container composed of the case 2 and the cover 3. A blocking portion is provided that includes a movable contact 6 that is driven to open and close via an opening / closing mechanism that does not.

The fixed contact 4 has a fixed contact 7 at one end, and a power source terminal 9 is integrally formed at the other end.
The movable contact 6 has a movable contact 8 that contacts the fixed contact 7 at one end, and the other end is rotatably connected to an insulating movable contact holder 10 that is rotatably supported by the case 2. And is biased toward the stationary contact 4 by a contact spring (not shown).

An arc extinguishing device 11 is disposed in the case 2.
As shown in FIG. 2, the arc-extinguishing device 11 has a pair of side wall support plates 12 and 12 arranged in parallel with each other, and a pair of side wall support plates 12 and 12 are layered with a gap in the vertical direction. It comprises a plurality of fixed grids 13 and a connecting plate 14 connected to the left side of the pair of side wall support plates 12 and 12. In the arc extinguishing device 11, a position opened on the right side between the pair of side wall support plates 12, 12 is referred to as an arc inlet 15, and is opposed to the left side connection plate 14 between the pair of side wall support plates 12, 12. This position is referred to as a gas outlet 16.

The pair of side wall support plates 12 and 12 and the connecting plate 14 are made of an electrically insulating material. A plurality of engagement holes 12a into which engagement projections 17b and 18b (described later) of the grid 13 are fitted are formed in the pair of side wall support plates 12 and 12, and the connection plate 14 has a plurality of gas exhaust ports 14a. Is formed penetrating in the thickness direction.
As shown in FIG. 3, the grid 13 is composed of two first and second arc drive plates 17 and 18 made of a magnetic material, and a resin superposed between the first and second arc drive plates 17 and 18. It consists of a plate 19.

The resin plate 19 is a rectangular member. The first and second arc drive plates 17 and 18 protrude from both end surfaces in the width direction of the plate bodies 17a and 18a having the same rectangular shape as the resin plate 19 and the plate bodies 17a and 18a. The engagement protrusions 17b and 18b are fitted into the engagement holes 12a.
Arc notches cut out from the center in the width direction toward the other end in the longitudinal direction at one end in the longitudinal direction (end on the arc inlet 15 side) of the plate bodies 17a, 18a and the resin plate 19 that are superposed in the same shape A groove 20 is formed.

  As shown in FIG. 3, a plurality of first gas blowing grooves 21 cut out toward the center in the width direction are formed in the longitudinal direction on both sides in the width direction of the first arc drive plate 17. As shown in FIG. 4, these first gas blowout grooves 21 are configured such that the gas outlet 16 has an outer opening 21 a that opens toward the outside air and an inner opening 21 b that opens toward the resin plate 19. Inclined to the gas outlet 16 side so as to be located on the side.

  As shown in FIG. 3, a plurality of second gas blowing grooves 22 cut out toward the center in the width direction are formed in the longitudinal direction on both sides in the width direction of the second arc drive plate 18. As shown in FIG. 4, these second gas blowout grooves 22 are configured such that the gas outlet 16 has an outer opening 22 a that opens toward the outside air and an inner opening 22 b that opens toward the resin plate 19. Inclined to the gas outlet 16 side so as to be located on the side.

Here, the second arc drive plate 18 has been described with a different reference to the first arc drive plate 17, but the first arc drive plate 17 is disposed on the lower surface of the resin plate 19 with the front and back surfaces reversed. Thus, the second arc drive plate 18 is configured. That is, the first arc driving plate 17 and the second arc driving plate 18 are members having the same shape.
The main body case according to the present invention corresponds to the case 2 and the cover 3, and the gas blowing portion according to the present invention corresponds to the first gas blowing groove 21 and the second gas blowing groove 22, and a pair of the present invention. The arc drive plates correspond to the first arc drive plate 17 and the second arc drive plate 18.

Next, the effect of 1st Embodiment is demonstrated with reference to FIGS. 1-5.
When a short circuit current or an overload current flows through the circuit breaker 1 having the above configuration, an electromagnetic repulsive force due to a concentrated current acts between the fixed contact 7 and the movable contact 8 as shown in FIG. The contact 6 opens against a biasing force of a contact spring (not shown). An arc 25 a is generated between the fixed contact 7 and the movable contact 8 simultaneously with the opening of the movable contact 6.

An arc gas 26 is generated by the arc 25 a between the fixed contact 7 and the movable contact 8, flows from the arc inlet 15 side of the arc extinguishing device 11 toward the gas outlet 16, and is extinguished from the gas exhaust port 14 a formed in the connecting plate 14. It flows outside the arc device 11.
The arc 25a generated between the fixed contact 7 and the movable contact 8 moves toward the arc inlet 15 of the arc extinguishing device 11 by the action of electromagnetic force, and the first and second arc driving of the grid 13 by the magnetic field of the arc current. Due to the deviation of the magnetic flux distribution passing through the plates 17 and 18, the arc is cut into the arc notch groove 20 formed in the grid 13 (the arc drawn into the arc notch groove 20 is referred to as arc 25b in FIG. 1).

Here, the arc 25 b drawn to the bottom of the arc notch groove 20 melts around the arc notch groove 20 of the resin plate 19 constituting the grid 13, and evaporative gas is generated from the resin plate 19. .
The evaporated gas generated by melting the resin plate 19 is a plurality of first gas blowing grooves 21 of the first arc driving plate 17 constituting the grid 13 and a plurality of second gas blowing grooves 22 of the second arc driving plate 18. As shown in FIG. 5, the gas is blown out as an ablation gas 27 from the arc inlet 15 side toward the gas outlet 16 side.

The arc 25 b drawn to the bottom of the arc notch groove 20 of the grid 13 does not act on the arc due to the deviation of the magnetic flux distribution passing through the grid 13.
However, the arc 25b drawn to the bottom of the arc notch groove 20 melts the resin plate 19 of the grid 13, so that the first gas blowing groove 21 and the second arc of the first arc driving plate 17 of the grid 13 are melted. Ablation gas 27 blows out from the second gas blowing groove 22 of the drive plate 18 toward the gas outlet 16 from the arc inlet 15 side.

  The arc 25b located in the arc notch groove 20 moves toward the gas outlet 16 side by the blowing of the ablation gas 27 and the gas flow from the arc inlet 15 side to the gas outlet 16 of the arc gas 26 described above. Thereby, the arc 25b toward the gas outlet 16 is divided by the first arc driving plate 17 and the second arc driving plate 18 of the plurality of grids 13 which are fixed in layers with a gap therebetween, and the first arc driving plate 17 is divided. Since the cooling is performed by transferring to the upper surface of the second arc driving plate 18 and the lower surface of the second arc driving plate 18, the arc 25b can be reliably extinguished.

Further, the arc 25b drawn into the arc notch groove 20 is blown by the ablation gas 27 and the arc gas 26, and the velocity toward the gas outlet 16 increases, so that the arc 25b does not stagnate on the grid 13 and in a short time. Dividing and cooling are performed, and the arc 25b can be extinguished efficiently.
Further, the gas outlet 16 is formed with respect to the inner opening 21b in which the outer opening 21a opening the first gas blowing groove 21 of the first arc driving plate 17 toward the outside air opens toward the resin plate 19. An outer opening 22a formed on the gas outlet 16 side so as to be located on the side and opening the second gas blowing groove 22 of the second arc drive plate 18 toward the outside air is formed in the resin plate 19. The arc inlet 15 is formed when the resin plate 19 of the grid 13 is melted only by being inclined to the gas outlet 16 side so as to be positioned on the gas outlet 16 side with respect to the inner opening 22b that is open. Since the blowing of the ablation gas 27 from the side toward the gas outlet 16 side can be easily formed, the manufacturing cost of the arc extinguishing device 11 can be reduced.

  A plurality of first gas blowing grooves 21 extending on both sides in the width direction of the first arc drive plate 17 are formed in the longitudinal direction, and extend on both sides in the width direction of the second arc drive plate 18. Since the grid 13 in which a plurality of second gas blowing grooves 22 are formed in the longitudinal direction is fixed in a layered manner with a gap in the vertical direction between the pair of side wall support plates 12, 12, a pair of side wall supports The flow of the ablation gas 27 from the arc inlet 15 side toward the gas outlet 16 side increases in the gaps between the grids 13 between the plates 12 and 12, and the arc 25b can be extinguished more efficiently.

Furthermore, the first and second arc drive plates 17 and 18 are parts having the same shape, and the parts that contact the lower surface of the resin plate 19 are reversed with respect to the parts that contact the upper surface of the resin plate 19 to form the grid 13. Since they are configured, the ease of assembling and the reduction of the manufacturing cost can be achieved by sharing the components constituting the grid 13.
In the first embodiment, the ablation gas 27 passes through the first gas blowing groove 21 formed in the first arc driving plate 17 and the second gas blowing groove 22 formed in the second arc driving plate 18 and the arc inlet 15. Although the gas blowing portion directed from the side toward the gas outlet 16 has been described, the gas blowing portion of the present invention is not limited to this structure. For example, the first arc driving plate 17 and the second arc driving plate 18 may be provided with gas. The same effect can be obtained even if a hole having a round shape, a semicircular shape, a polygonal shape, or the like inclined toward the outlet 16 is formed so as to communicate with the outside air from the resin plate 19.

DESCRIPTION OF SYMBOLS 1 Circuit breaker 2 Case 3 Cover 4 Fixed contact 5 Handle 6 Movable contact 7 Fixed contact 8 Movable contact 9 Power supply side terminal 10 Movable contact holder 11 Arc-extinguishing device 12 Side wall support plate 12a Engagement hole 13 Grid 14 Connection plate 14a Gas exhaust port 15 Arc inlet 16 Gas outlet 17 First arc drive plate 18 Second arc drive plate 19 Resin plates 17a, 18a Plate bodies 17b, 18b Engaging protrusion 20 Arc notch groove 21 First gas blowing groove 21a Outside Opening 21b Inner opening 22 Second gas blowing groove 22a Outer opening 22b Inner openings 25a, 25b Arc 26 Arc gas 27 Ablation gas

Claims (5)

In the body case,
A stationary contact having a stationary contact;
A movable contact having a movable contact contacting and separating from the fixed contact;
An arc extinguishing device that extinguishes an arc generated between the fixed contact and the movable contact;
The arc extinguishing device has a plurality of grids, one end of which is located on the arc inlet side near the fixed contact and the movable contact, and the other end is located on the gas outlet side, and is arranged in a layered manner with a gap between them. And
The plurality of grids include a pair of arc drive plates made of a magnetic material, and a resin plate superimposed between the pair of arc drive plates,
An arc notch groove is formed at the end of the arc entrance side of the pair of arc drive plates and the resin plate,
The circuit breaker characterized in that the pair of arc driving plates are formed with gas blowing portions for blowing out the evaporated gas generated by melting the resin plate as ablation gas from the arc inlet side toward the gas outlet side. vessel.   The pair of arc drives is configured such that the outer opening that opens toward the outside air is positioned on the gas outlet side with respect to the inner opening that opens toward the resin plate. 2. The circuit breaker according to claim 1, wherein the circuit breaker communicates with the front and back sides of the plate at an angle.   3. The circuit breaker according to claim 1, wherein a plurality of the gas blowing portions are formed on both side portions from the arc inlet side to the gas outlet of the pair of arc drive plates.   The gas blowing portion is formed by a notch from both sides of the pair of arc drive plates toward the inside, and an outside opening that opens toward the outside air opens toward the resin plate. The circuit breaker according to any one of claims 1 to 3, wherein the circuit breaker is a gas blowing groove located on the gas outlet side with respect to the opening.   The pair of arc drive plates are two parts having the same shape, and one part is superposed on one surface of the resin plate, and the other part is reversed and superposed on the other surface of the resin plate. The circuit breaker according to any one of claims 1 to 4.

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