JP6822257B2 - Circuit breaker - Google Patents

Description

The present invention relates to a circuit breaker such as a molded case circuit breaker and an earth leakage breaker, in which a pair of gap extinguishing plates are arranged on both sides of an open pole movement path of a movable contact.

A circuit breaker is a device in which a movable contactor makes a contact operation or a separation operation with respect to a fixed contactor to open and close the main circuit, and when a short-circuit current is cut off, the fixed contact of the fixed contactor and the movable contactor When an arc is generated between the movable contacts, the arc extinguishing device extinguishes the arc (for example, Patent Document 1).
In the arc extinguishing device, a plurality of grids formed in a U-shape or a V-shape and having a pair of grid legs extending in parallel from the grid base are arranged in layers, and between the pair of grid legs. A pair of gap extinguishing plates are arranged so as to surround the movement locus of the movable contact from both sides.

When the short-circuit current is cut off, the fixed contact and movable contact are due to the gap effect of the pair of gap extinguishing plates (contact between the arc and the gap extinguishing plate and the cooling effect of the arc by the pyrolysis gas of the gap extinguishing plate). In the arc generated during the period, the arc voltage is rapidly increased and the current peak is suppressed. Then, the arc further extended between the fixed contact and the movable contact moves from between the pair of gap extinguishing plates to the plurality of grids, and is divided and cooled by the contact with the plurality of grids to extinguish the arc. Will be done.

Japanese Unexamined Patent Publication No. 2008-2436559

By the way, in the circuit breaker having the above-described configuration, the arc generated between the fixed contact and the movable contact immediately shifts from between the pair of gap extinguishing plates to the plurality of grids, and between the pair of gap extinguishing plates. Since the arc is not sufficiently cooled and the arc voltage does not increase, the current limiting performance may deteriorate.
Also. When a high-temperature arc comes into contact with the grid, the arc is divided and the cooling action is deteriorated, and the grid may be thermally damaged such as being blown off, and the breaking performance may be deteriorated.
Therefore, an object of the present invention is to provide a circuit breaker capable of improving current limiting performance and breaking performance by sufficiently cooling the arc generated between the fixed contact and the movable contact.

In order to achieve the above object, the circuit breaker according to one aspect of the present invention includes a fixed contact provided with a fixed contact and a movable contact provided with a movable contact capable of contacting the fixed contact in the main body case. The arc-extinguishing device is housed, and the arc-extinguishing device includes a plurality of grids formed in a U-shape or a V-shape, and a pair of grid legs extending in parallel from the grid base and arranged in layers. A pair of narrow gap extinguishing plates arranged so as to surround the movement loci of movable contacts from both sides are provided between a pair of grid legs of a plurality of grids, and the pair of narrow gap arc extinguishing plates are provided on the grid base side. , The band-shaped convex portion is formed, and the band-shaped convex portion is formed to have a wide width on the side close to the fixed contact and a narrow width as the distance from the fixed contact increases.

According to the circuit breaker according to the present invention, the current limiting performance and the breaking performance are improved by sufficiently cooling the arc generated between the fixed contact and the movable contact.

It is sectional drawing which shows the structure of a circuit breaker. It is a figure which shows the arc extinguishing apparatus of the circuit breaker of 1st Embodiment. It is a view of arrow AA of FIG. It is a figure which shows the arc extinguishing apparatus of the circuit breaker of 2nd Embodiment. It is a view of arrow BB of FIG. It is a figure which shows the arc extinguishing apparatus of the circuit breaker of 3rd Embodiment. FIG. 6 is a view taken along the line CC of FIG. It is a figure which shows the arc extinguishing device of the circuit breaker of 4th Embodiment. FIG. 8 is a view taken along the line DD of FIG. It is a figure which shows the main part of the arc extinguishing apparatus of the circuit breaker of 5th Embodiment.

Next, the first to fifth embodiments of the present invention will be described with reference to the drawings. In the description of the drawings below, the same or similar parts are designated by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the plane dimension, the ratio of the thickness of each layer, etc. are different from the actual ones. Therefore, the specific thickness and dimensions should be determined in consideration of the following explanation. In addition, it goes without saying that the drawings include parts having different dimensional relationships and ratios from each other.

Further, the first to fifth embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is based on the material of the component parts. The shape, structure, arrangement, etc. are not specified as follows. The technical idea of the present invention may be modified in various ways within the technical scope specified by the claims stated in the claims.

[Circuit breaker of the first embodiment]
1 to 3 show the circuit breaker of the first embodiment.
As shown in FIG. 1, in the circuit breaker of the first embodiment, an arc extinguishing device 3, an overcurrent tripping device 4, a fixed contact 5 and a fixed contact 5 are provided in an insulating container including a case 1 and a cover 2. A movable contact 6, a holder 7 for rotatably holding the movable contact 6, and an opening / closing mechanism 15 for opening / closing the movable contact 6 via the holder 7 are arranged.

The fixed contact 5 has a power supply side terminal 5a formed on one end side and a fixed contact 5b formed on the other end side. The movable contact 6 is formed with a movable contact 6a that contacts the fixed contact 5b of the fixed contact 5.
Further, the cover 2 is composed of a middle cover 2a and a top cover 2b.
One end of the flexible lead wire 8 is connected to the base end of the movable contact 6, and the other end of the lead wire 8 is connected to one end of the relay conductor 9 via the electric wire connecting plate 10.

The relay conductor 9 is bent from the lower flat plate portion 9b connected to the electric wire connecting plate 10, the rising plate portion 9c rising from the end of the lower flat plate portion 9b, and the upper end of the rising plate portion 9c, with respect to the lower flat plate portion 9b. It is provided with an upper flat plate portion 9d extending in parallel and extending in a direction away from the lower flat plate portion 9b, and a load side terminal 9a formed on the other end side of the upper flat plate portion 9d. The rising plate portion 9c of the relay conductor 9 serves as a heater (hereinafter, referred to as a heater 9c).

The opening / closing mechanism 15 engages with a handle 16 that performs an opening / closing operation, a handle lever 17 that operates in conjunction with the handle 16, a toggle link mechanism 21 including an upper toggle 18 and a lower toggle 19, a latch 20, and a latch 20. It is provided with a latch receiver 22, an intermediate latch 23, and a trip bar 24 for rotating the intermediate latch 23 to disengage the latch 20 and the latch receiver 22. The upper toggle 18 and the lower toggle 19 are connected to each other via a toggle pin 25, the upper end of the upper toggle 18 is rotatably connected to the latch 20, and the lower toggle 19 is connected to the holder 7. Further, the lower end hook portion of the spring (not shown) is hooked on the toggle pin 25, and the upper end hook portion of the spring is hooked on the upper end of the handle lever 17.

The overcurrent trip device 4 has a bimetal 26 whose lower portion is fixed to the rising plate portion 9c of the relay conductor 9 and an extension plate 27 which is fixed to the free end of the upper part of the bimetal 26 and extends to the vicinity of the trip bar 24. The adjusting screw 28, which is engaged with the free end of the upper part of the extension plate 27 and can be moved forward and backward so as to provide a predetermined gap between the extension plate 27 and the trip bar 24, and the heater 9c crimped and fixed to the lower part of the bimetal 26. When a large current such as a short-circuit current flows between the power supply side terminal 5a and the load side terminal 9a, the trip bar 24 is hit at the tip to disengage the latch 20 and the latch receiver 22, and an armature 30 and a fixed magnet 29 are provided. ing.

As shown in FIGS. 2 and 3, the arc extinguishing device 3 is a device for extinguishing an arc generated due to an opening / closing operation between the fixed contact 5b and the movable contact 6a, and includes a plurality of grids 33. A pair of supporters 34, 35 that support a plurality of grids 33 arranged in layers, and a pair of gap extinguishing plates 36, arranged between a pair of grid legs 32 of each grid 33 arranged in layers. 37 and.

The grid 33 is a U-shaped or V-shaped member made of magnetic metal, and a pair of grid legs 32 extend in parallel from the grid base 31. The pair of supports 34, 35 support the outside of the plurality of grids 33 arranged in layers.
The pair of gap extinguishing plates 36 and 37 are members made of a polymer material such as plastic, and movable contacts 6a are arranged at intermediate positions between the facing surfaces 36a and 37a.

On the facing surfaces 36a and 37a of the pair of gap extinguishing plates 36 and 37, as a band-shaped convex portion in a direction close to each other at a position closer to the grid base 31 side of the grid 33 than the movement locus T of the movable contact 6a. The convex portions 38 and 39 of the above are formed. These convex portions 38 and 39 have a rectangular cross section, are continuous in a strip shape from the start point to the end point of the movement locus T of the movable contact 6a, and project from each other with the same height dimension d1.

Next, the operation and the effect of the circuit breaker of the first embodiment will be described.
In the circuit breaker of the first embodiment, when the fixed contact 5 and the movable contact 6 are closed, the power supply side terminal 5a, the fixed contact 5, the movable contact 6, the lead wire 8, and the electric wire connection plate are used. 10. Current flows in the current path of the heater 9c, the relay conductor 9, and the load side terminal 9a.
Then, when the current flowing through the current path becomes overloaded, the bimetal 26 is curved counterclockwise due to the heat generated from the heater 9c, and at the same time, the extension plate 27 fixed to the bimetal 26 also rotates counterclockwise. The tip of the adjusting screw 28 comes into contact with the trip bar 24, and the trip bar 24 rotates counterclockwise around the support shaft 24a. The rotation of the trip bar 24 causes the intermediate latch 23 to rotate, the latch 20 and the latch receiver 22 to be disengaged, the toggle link mechanism 21 to operate, and the holder 7 connected to the lower toggle 19 to rotate. The movable contact 6 is separated from the fixed contact 5 to be in an open pole state.

Further, when a large current such as a short-circuit current flows through the heater 9c, the armature 30 of the overcurrent trip device 4 rotates counterclockwise and is instantly attracted to the fixed magnet 29, and the trip bar 24 is pressed at the tip thereof. Hit. Then, when the trip bar 24 is hit, the latch 20 and the latch receiver 22 are disengaged, the toggle link mechanism 21 operates, the holder 7 connected to the lower toggle 19 rotates, and the movable contact 6 is fixed. It is separated from the contactor 5 and becomes an open pole.

When the movable contact 6a is separated from the fixed contact 5b by the opening operation when the short-circuit current is cut off, the surface of the pair of gap extinguishing plates 36 and 37 is generated by the heat of the arc generated between the movable contact 6a and the fixed contact 5b. Pyrolysis gas is generated from. At this time, the arc is cooled by the contact with the gap extinguishing plates 36 and 37, and the arc is cooled by the pyrolysis gas, so that the arc voltage is increased and the current peak is suppressed.

Then, the arc extended by the movable contact 6a being further separated from the fixed contact 5b is blown by the gas flow of the pyrolysis gas from between the pair of gap extinguishing plates 36 and 37 to the plurality of grid 33 sides. It shifts and is divided and cooled by contact with a plurality of grids 33.
Here, the arc extinguishing device 3 of the circuit breaker of the first embodiment has a band-shaped convex portion 38, located at a position closer to the grid base 31 side of the facing surfaces 36a, 37a of the pair of narrow space arc extinguishing plates 36, 37. Since 39 is provided, the arc generated between the pair of gap extinguishing plates 36, 37 passes through the narrow space between the convex portions 38, 39 and moves to the plurality of grid 33 sides. A lot of time goes by.

As a result, the time for the arc to stay between the pair of gap extinguishing plates 36 and 37 becomes longer. The time during which the arc stays between the pair of gap extinguishing plates 36 and 37 is such that the fixed contact 5b and the movable contact 6a are not consumed by the heat of the arc.
In this way, when the arc stays between the pair of gap extinguishing plates 36 and 37 for a long time, the arc is sufficiently cooled by the contact with the gap extinguishing plates 36 and 37, and the pyrolysis gas is decomposed. The arc is sufficiently cooled by the contact with the arc, the temperature of the arc is lowered, and the arc voltage is increased, so that the current limiting performance can be improved.

Further, the arc whose temperature has decreased is prevented from being thermally damaged such as being blown off even if it comes into contact with the grid 33, and the arc is divided and the cooling action is enhanced, so that the breaking performance can be improved.
Further, for example, even if the metal vapor generated by melting the grid 33 causes a flow of moving the arc to the grid 33 side to the pair of gap extinguishing plates 36 and 37, the pair of gap extinguishing Since the convex portions 38, 39 formed on the arc plates 36, 37 prevent the arc from being transferred between the pair of gap extinguishing plates 36, 37, the recurrence arc can be prevented.

[Pair gap extinguishing plate of the second embodiment]
Next, FIGS. 4 and 5 show an arc extinguishing device 3 constituting the circuit breaker of the second embodiment. The same components as those shown in FIGS. 1 to 3 are designated by the same reference numerals, and the description thereof will be omitted.
On the facing surface 36a of one of the gap extinguishing plates 36 of the second embodiment, the starting point of the moving locus T of the movable contact 6a is located closer to the grid base 31 side of the grid 33 than the moving locus T of the movable contact 6a. A convex portion 40 is formed as a strip-shaped convex portion having the same width and continuous in a strip shape from the to the end point side.

The convex portion 40 has a rectangular cross section, and the side of the movable contact 6a near the start point of the movement locus T protrudes with a height dimension d1, and the height dimension gradually decreases from the start point to the end point. At the same time, the convex portion 40 is not formed at the end point.
Further, the facing surface 37a of the gap extinguishing plate 37 facing the facing surface 36a of one of the gap extinguishing plates 36 is also closer to the grid base 31 side of the grid 33 than the movement locus T of the movable contact 6a. At the position, a convex portion 41 as a band-shaped convex portion facing the convex portion 40 formed on the facing surface 36a is formed.

The convex portion 41 also has a rectangular cross section, and the side of the movable contact 6a near the start point of the movement locus T protrudes with a height dimension d1, and the height dimension gradually decreases from the start point to the end point. At the same time, the convex portion 41 is not formed at the end point.
According to the circuit breaker of the second embodiment, when the movable contact 6a is separated from the fixed contact 5b and an arc is generated by the opening operation when the short-circuit current is cut off, the facing surfaces 36a of the pair of gap extinguishing plates 36 and 37 , 37a Since the band-shaped convex portions 40 and 41 are provided at positions closer to the grid base 31 side, the arc between the pair of narrow gap extinguishing plates 36 and 37 has a long residence time and the fine gap disappears. The arc is sufficiently cooled by the contact with the arc plates 36 and 37, and the arc is sufficiently cooled by the contact with the pyrolysis gas, the temperature of the arc is lowered, and the arc voltage is increased. The blocking performance can be improved.

Further, the contact time with the arc is longer on the side of the movable contacts 6a of the convex portions 40 and 41 of the second embodiment near the start point of the movement locus T, but the height dimension (d1) on the start point side of the movement locus T is increased. As a result, the convex portions 40 and 41 sufficiently withstand thermal deformation due to contact with the arc can be provided, and a pair of gap extinguishing plates 36 and 37 that prevent thermal damage can be provided.

[Circuit breaker of the third embodiment]
Next, FIGS. 6 and 7 show an arc extinguishing device 3 constituting the circuit breaker of the third embodiment.
On the facing surface 36a of one of the gap extinguishing plates 36 of the third embodiment, the start point of the movement locus T of the movable contact 6a is located closer to the grid base 31 side of the grid 33 than the movement locus T of the movable contact 6a. A convex portion 42 is formed as a strip-shaped convex portion continuous from the to the end point.

The convex portion 42 has a rectangular cross section, protrudes from the start point of the movement locus T of the movable contact 6a along the end point with a height dimension d1, and is a start point with respect to the width dimension h1 on the end point side of the movement locus T. The width dimension h2 on the side is set to a large dimension (h2> h1), and the width dimension is formed so as to gradually decrease from the start point to the end point.
Further, the facing surface 37a of the gap extinguishing plate 37 facing the facing surface 36a of one of the gap extinguishing plates 36 is also closer to the grid base 31 side of the grid 33 than the movement locus T of the movable contact 6a. At the position, a convex portion 43 as a band-shaped convex portion facing the convex portion 40 formed on the facing surface 36a is formed.

The convex portion 43 also has a rectangular cross section, protrudes from the start point to the end point of the movement locus T of the movable contact 6a with a height dimension d1, and is on the start point side with respect to the width dimension h1 on the end point side of the movement locus T. The width dimension h2 of the above is set to a large dimension (h2> h1), and the width dimension is formed so as to gradually decrease from the start point to the end point.

According to the circuit breaker of the third embodiment, when the movable contact 6a is separated from the fixed contact 5b and an arc is generated by the opening operation when the short-circuit current is cut off, the facing surfaces 36a of the pair of gap extinguishing plates 36 and 37 , 37a Since the band-shaped convex portions 40 and 41 are provided at positions closer to the grid base 31 side, the arc between the pair of narrow gap extinguishing plates 36 and 37 has a long residence time and the fine gap disappears. The arc is sufficiently cooled by the contact with the arc plates 36 and 37, and the arc is sufficiently cooled by the contact with the pyrolysis gas, the temperature of the arc is lowered, and the arc voltage is increased. The blocking performance can be improved.

Further, the contact time with the arc is longer on the side of the movable contacts 6a of the convex portions 42 and 43 of the third embodiment near the start point of the movement locus T, but the width dimension (h2) on the start point side of the movement locus T is increased. As a result, the convex portions 42 and 43 are sufficiently resistant to thermal deformation due to contact with the arc, and a pair of gap extinguishing plates 36 and 37 that prevent thermal damage can be provided.

[Circuit breaker of the fourth embodiment]
Next, FIGS. 8 and 9 show an arc extinguishing device 3 constituting the circuit breaker of the fourth embodiment.
On the facing surface 36a of one of the gap extinguishing plates 36 of the third embodiment, a convex portion 44 as a band-shaped convex portion is formed at a position closer to the grid base 31 side of the grid 33 than the movement locus T of the movable contact 6a. Has been done.
The convex portion 44 has a rectangular cross section, is continuous in a band shape in a region from the start point to the intermediate position of the movement locus T of the movable contact 6a, and is formed so as to project with a height dimension d1.

Further, the facing surface 37a of the gap extinguishing plate 37 facing the facing surface 36a of one of the gap extinguishing plates 36 is also closer to the grid base 31 side of the grid 33 than the movement locus T of the movable contact 6a. At the position, a convex portion 45 as a band-shaped convex portion facing the convex portion 42 formed on the facing surface 36a is formed.
The convex portion 45 also has a rectangular cross section, is continuous in a band shape in a region from the start point to the intermediate position of the movement locus T of the movable contact 6a, and is formed so as to project with a height dimension d1.

When the movable contact 6a is separated from the fixed contact 5b and an arc is generated due to the opening operation when the short-circuit current is cut off, the arc immediately after the movable contact 6a is separated from the fixed contact 5b is hot, and this high temperature arc is the grid 33. When it comes into contact with, the grid 33 causes thermal damage such as fusing and falling off.
In the fourth embodiment, a band-shaped convex portion from the start point to the intermediate position of the movement locus T of the movable contact 6a is located at a position closer to the grid base 31 side of the facing surfaces 36a, 37a of the pair of gap extinguishing plates 36, 37. By providing 44, 45, the band-shaped convex portions 44, 45 can prevent the high temperature arc from flowing toward the grid 33 side, and the thermal damage of the grid 33 can be surely prevented.

[Circuit breaker of the fifth embodiment]
Next, FIG. 10 shows a main part of the circuit breaker of the fifth embodiment.
The convex portion 46 as a band-shaped convex portion formed on the facing surface 36a of one of the gap extinguishing plates 36 of the fifth embodiment has a semicircular cross section and follows the movement locus T of the movable contact 6a. It is continuous in a strip shape.
Further, although not shown, a cross section of the facing surface 37a of the other gap extinguishing plate 37 facing the facing surface 36a of one gap extinguishing plate 36 along the movement locus T of the movable contact 6a. A semicircular convex portion 46 is formed.

The convex portion 46 having a semicircular cross section formed on the facing surfaces 36a and 37a of the pair of gap extinguishing plates 36 and 37 of the fifth embodiment is locally contacted with a high temperature arc such as a corner portion. It is possible to provide a pair of gap extinguishing plates 36, 37 which can sufficiently withstand thermal deformation and prevent thermal damage because there is no portion to be formed.
The convex portion 46 of the fifth embodiment may be applied to the convex portion of the first to fourth embodiments. Further, the shape of the convex portion 46 is not limited to the semicircular cross-sectional shape, and the same effect can be obtained even if the convex portion 46 has a rounded shape such as a semi-elliptical cross-sectional shape.

1 Case 2 Cover 2a Middle cover 2b Top cover 3 Arc extinguishing device 4 Overcurrent trip device 5 Fixed contact 5a Power supply side terminal 5b Fixed contact 6 Movable contact 6a Movable contact 7 Holder 8 Lead wire 9 Relay conductor 9a Load side terminal 9b Lower flat plate 9c Heater 9d Upper flat plate 10 Wire connection plate 15 Opening and closing mechanism 16 Handle 17 Handle lever 18 Upper toggle 19 Lower toggle 20 Latch 21 Toggle link mechanism 22 Latch receiver 23 Intermediate latch 24 Trip bar 25 Toggle pin 26 Bimetal 27 Extension plate 28 Adjusting screw 29 Fixing magnet 30 Armature 31 Grid base 32 Grid leg 33 Grid 34,35 Support 36,37 Gap extinguishing plate 38, 39, 40, 41, 42, 43, 44, 45, 46 Convex part T Movement trajectory of movable contact

Claims (3)

A fixed contact provided with a fixed contact, a movable contact provided with a movable contact capable of contacting the fixed contact, and an arc extinguishing device are housed in the main body case.
The arc extinguishing device includes a plurality of grids formed in a U-shape or a V-shape, and a pair of grid legs extending in parallel from the grid base and arranged in layers.
A pair of narrow gap extinguishing plates arranged so as to surround the movement locus of the movable contact from both sides are provided between the pair of grid legs of the plurality of grids.
A band-shaped convex portion is formed on the grid base side of the pair of gap extinguishing plates .
A circuit breaker characterized in that the strip-shaped convex portion has a wide width on the side close to the fixed contact and is formed to have a narrow width as the distance from the fixed contact increases . In the pair of gap extinguishing plates, a pair of strip-shaped convex portions are formed along the movement locus on the surfaces facing each other at positions closer to the grid base side with respect to the movement locus of the movable contact. The circuit breaker according to claim 1, wherein the circuit breaker is provided. The circuit breaker according to claim 1 or 2, wherein the strip-shaped convex portion has a rounded shape such as a semicircular shape or a semi-elliptical shape in cross section.

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