Arc extinguishing system of miniature circuit breaker and miniature circuit breaker

Abstract

The utility model discloses an arc extinguishing system of a miniature circuit breaker and the miniature circuit breaker. The arc extinguishing system comprises an arc extinguishing chamber, an arc isolating piece and a magnetic conductive plate, the arc extinguish chamber comprises at least two arc extinguish grid sheets which are stacked in sequence along a first direction; the arc-extinguishing grid sheet is provided with two grid sheet pins, an arc-extinguishing groove is formed between the two grid sheet pins, and the opening of the arc-extinguishing groove of the arc-extinguishing grid sheet faces the breaking area; wherein the arc-isolating pieces are made of gas production materials, the number of the arc-isolating pieces is two, and the arc-isolating pieces are arranged on the two sides of the breaking area respectively and correspond to the two grid piece pins of the same arc-extinguishing grid piece respectively; a guide part is arranged on the arc isolating piece and extends into the arc quenching groove to shield the end part of the corresponding grid piece pin; the number of the magnetic conductive plates is two, and the magnetic conductive plates are fixed to the surfaces, away from the breaking area, of the two arc isolating pieces respectively. The arc extinguishing device has the advantage of being better in arc extinguishing effect.

Description

TECHNICAL FIELD

[0001] The application relates to a miniature circuit breaker. BACKGROUND

[0002] An arc extinguishing system is an indispensable part of a miniature circuit breaker. An arc generated when a moving contact and a stationary contact are separated is mainly extinguished by the arc extinguishing system.

[0003] An arc extinguishing system of an existing miniature circuit breaker comprises an arc extinguishing chamber, gas generating plates located in front of the arc extinguishing chamber, and magnetic conductive sheets. An opening of the arc extinguishing chamber faces a separation area of the miniature circuit breaker. The number of the gas generating plates is two, which are arranged on the front and back sides of the separation area. The number of the magnetic conductive sheets is also two, which are fixed on surfaces of the two gas generating plates (also called arc separation plates) away from the separation area. When the moving contact and the stationary contact are separated, gas blowing (high-temperature gas generated under arc burning) and magnetic blowing (magnetic field generated by the magnetic conductive sheets under the influence of the arc, which exerts a magnetic force on the arc to make the arc more easily deviate to the arc extinguishing chamber) are formed by the gas generating plates.

[0004] A magnetic blowing type arc separation plate and a miniature circuit breaker arc extinguishing system using the same disclosed in CN211182023U adopt such a structure.

[0005] However, although the existing gas generating plates can generate gas, the effect of guiding the arc is not ideal. In addition, it is found in a large number of separation tests that the end part of the grid foot is particularly easy to be ablated, which is not conducive to arc extinguishing.

[0006] Therefore, how to design a more reasonable arc extinguishing system of a miniature circuit breaker has become a problem worth considering. SUMMARY

[0007] Therefore, the application aims to overcome the deficiencies in the prior art and provides an arc extinguishing system of a miniature circuit breaker and a miniature circuit breaker.

[0008] The application provides an arc extinguishing system of a miniature circuit breaker, which comprises an arc extinguishing chamber, arc separation pieces, and magnetic conductive plates. The arc extinguishing chamber comprises at least two arc extinguishing grid sheets, each of which is stacked in sequence along a first direction. Two grid feet are arranged on each arc extinguishing grid sheet, and an arc extinguishing groove is formed between the two grid feet. The opening of the arc extinguishing groove of the arc extinguishing grid sheet faces a separation area. The arc separation pieces are made of a gas generating material, and the number of the arc separation pieces is two, which are arranged on the two sides of the separation area and correspond to the two grid feet of the same arc extinguishing grid sheet. The arc separation pieces have a guide part, which extends into the arc extinguishing groove and shields the end part of the corresponding grid foot. The number of the magnetic conductive plates is two, and each of the magnetic conductive plates is fixed on a surface of the two arc separation pieces away from the separation area.

[0009] In some embodiments of the present application, the arc separation piece further comprises a main body part, the guide part is connected to the main body part at one end close to the arc extinguishing grid, the guide part is inclined towards the inside of the arc extinguishing groove, and the guide part forms an obtuse angle with the main body part.

[0010] In some embodiments of the present application, the distance between the guide parts of the two arc separation pieces gradually decreases from the end close to the main body part to the end away from the main body part.

[0011] In some embodiments of the present application, the guide part is provided with a slot adapted to the number of grid feet, and the end head part of the grid foot is inserted into the slot.

[0012] In some embodiments of the present application, the grid foot comprises a first surface, an end head surface, and a second surface, the first surface and the second surface are connected by the end head surface; the second surfaces of the two grid feet are connected to form the arc extinguishing groove together; the connection between the end head surface and the second surface is inserted into the slot, and the part of the end head surface outside the slot is redundant compared to the part of the end head surface inside the slot.

[0013] In some embodiments of the present application, one of the slot walls of the slot is a stop wall, and the stop wall is in abutment with the end head surface.

[0014] In some embodiments of the present application, the part of the second surface inside the slot is a bevel or an arc surface or a combination of two bevels with different slopes connected in sequence.

[0015] In some embodiments of the present application, the surface of the arc separation piece away from the breaking area is provided with a mounting slot, and the magnetic conducting plate is in interference fit with the mounting slot.

[0016] In some embodiments of the present application, the mounting slot comprises a slot bottom and a side wall surrounding the slot bottom, the side wall is provided with a convex point, and the side surface of the magnetic conducting plate is in interference fit with the convex point.

[0017] In some embodiments of the present application, the mounting slot has a positioning column, the arc-shaped side surface of the positioning column is provided with a convex point, and the magnetic conducting plate is provided with a positioning hole adapted to the positioning column, and the hole wall of the positioning hole is in interference fit with the convex point.

[0018] A miniature circuit breaker comprises at least one pole circuit breaker unit, each pole circuit breaker unit having a circuit breaker housing, an operating mechanism, and movable and stationary contacts; wherein the miniature circuit breaker further comprises an arc extinguishing system as described above.

[0019] The present application has the following beneficial effects compared with the prior art:

[0020] First, the structure that the guide part is arranged on the arc separation plate, and the guide part extends into the arc extinguishing groove, which is beneficial to the arc gas entering into the arc extinguishing groove to be extinguished, so that the arc gas is more concentrated, and the arc extinguishing effect is improved.

[0021] Second, the guide part shields the end head part of the grid foot, which can prevent the arc ablation of the end head part, and has the effect of protecting the end head part. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0023] Figure 1 The internal schematic diagram of the miniature circuit breaker of the embodiment of the present application is shown;

[0024] Figure 2 The schematic diagram of part of the circuit breaker shell of the miniature circuit breaker of the embodiment of the present application is shown;

[0025] Figure 3 The schematic diagram of the arc extinguishing system in the embodiment of the present application is shown;

[0026] Figure 4 The schematic diagram of the arc extinguishing grid in the embodiment of the present application is shown;

[0027] Figure 5 The schematic diagram of the grid foot of the arc extinguishing grid in the embodiment of the present application is shown;

[0028] Figure 6 The schematic diagram of the arc separation piece in the embodiment of the present application is shown;

[0029] Figure 7 The schematic diagram of one embodiment of the cooperation of the arc separation piece and the magnetic conducting plate in the embodiment of the present application is shown;

[0030] Figure 8 The schematic diagram of another embodiment of the cooperation of the arc separation piece and the magnetic conducting plate in the embodiment of the present application is shown. DETAILED DESCRIPTION

[0031] The embodiments of the present application will be described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, and are only used to explain the present application, and cannot be understood as a limitation on the present application.

[0032] In the description of the application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0033] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the application, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0034] In this application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0035] In this application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature. Embodiment

[0036] As shown in Figures 1-8 The embodiment of the application is a miniature circuit breaker, which is also called an air switch. In this embodiment, it is a single-pole circuit breaker, that is, it only contains one pole circuit breaker unit P. Of course, the miniature circuit breaker also includes multiple poles, that is, multiple circuit breaker units P, for example, a 2-4 pole circuit breaker contains 2-4 circuit breaker units P.

[0037] The circuit breaker unit P comprises a circuit breaker housing 100 and an operating mechanism, an arc extinguishing system, a contact system, a transient protection system and an overload protection system arranged in the housing.

[0038] The operating mechanism is used to realize the connection and disconnection of the movable and static contacts 300. Since the operating mechanism is not the point of the present application and belongs to the prior art, it will not be described here.

[0039] The contact system comprises the movable contact 200 and the static contact 300. The circuit breaker housing 100 has an arc extinguishing area 102, which is the area where the movable contact 200 and the static contact 300 are connected and disconnected.

[0040] The transient protection system adopts a solenoid type electromagnetic release, which is actuated when a short circuit exists in the main circuit of the circuit breaker, so as to trip the operating mechanism. Since the solenoid type electromagnetic release belongs to the prior art, it will not be described here.

[0041] The overload protection system adopts a bimetallic strip, which is bent when an overload exists in the main circuit of the circuit breaker, so as to trip the operating mechanism. Since the bimetallic strip belongs to the prior art, it will not be described here.

[0042] The arc extinguishing system comprises an arc extinguishing chamber 400, an arc separation piece 500 and a magnetic conducting plate 600.

[0043] The circuit breaker housing 100 has an arc extinguishing area 101 inside, and the arc extinguishing chamber 400 is installed in the arc extinguishing area 101.

[0044] The arc extinguishing chamber 400 comprises 12 arc extinguishing grid pieces 410 and an arc extinguishing cover 420, and the 12 arc extinguishing grid pieces 410 are clamped on the arc extinguishing cover 420. The 12 arc extinguishing grid pieces 410 are stacked in a first direction in order, and the first direction here is the height direction of the circuit breaker unit P. Of course, the arc extinguishing grid pieces 410 here are not limited to 12, and can be more or less, as long as there are at least 2. The actual number of the arc extinguishing grid pieces 410 is determined according to the space size of the arc extinguishing area 101 and the size of the arc extinguishing grid pieces 410.

[0045] Each arc extinguishing grid piece 410 has two grid piece feet 412 and a main plate 411, and the two grid piece feet 412 are connected to the main plate 411 at the same end. An arc extinguishing groove 413 is formed between the two grid piece feet 412, and the opening direction of the arc extinguishing groove 413 is towards the disconnection area 101, so that the arc generated when the movable and static contacts 300 are disconnected can enter the arc extinguishing groove 413.

[0046] The arc separation piece 500 is a gas generating material, which is PA66 (polyamide) here. Of course, any insulating material that can generate gas when heated can be used here.

[0047] The number of arc separation pieces 500 is two, which are respectively arranged on both sides of the arc extinguishing area 102, and the two sides here are the front and back sides of the arc extinguishing area 102.

[0048] The two arc separation pieces 500 correspond to the two grid feet 412 of the arc extinguishing grid 410 respectively, and each arc separation piece 500 comprises a main body part 501 and a guide part 502. The guide part 502 is connected to one end of the main body part 501 close to the arc extinguishing grid 410, and the guide part 502 extends obliquely towards the arc extinguishing groove 413. Here, the guide part 502 forms an obtuse angle with the main body part 501. The guide part 502 shields the end head part 4120 of the corresponding grid foot 412. Here, since the number of arc extinguishing grids 410 is 12, the total number of grid feet 412 is 24, and the 24 grid feet 412 are divided into two groups, one of which is shielded by one guide part 502, and the other is shielded by the other guide part 502. Of course, the shielding of the end head part 4120 here does not mean that the end head part 4120 is completely surrounded, but only needs to shield the surface of the end head part 4120 towards the arc extinguishing area 102.

[0049] Such a structure, when breaking, the arc separation piece 500 generates gas under the action of high-temperature arc, and the gas can extend along the guide part 502 to the arc extinguishing groove 413, which is conducive to the more concentrated movement of arc gas to the arc extinguishing groove 413 for extinguishing. At the same time, the guide part 502 shields the end head part 4120 of the grid foot 412, which can prevent arc ablation of the end head part 4120 and protect the end head part 4120.

[0050] Here, the distance between the two guide parts 502 gradually decreases from one end close to the main body part 501 to the other end away from the main body. That is, the guide parts 502 can form a structure of Laval nozzle S, which will facilitate the rapid entry of arc gas into the arc extinguishing groove 413 and improve the arc extinguishing effect.

[0051] For the guide part 502, it is provided with 12 insertion slots 5021 for the corresponding 12 grid feet 412. Here, the number of insertion slots 5021 is not limited to 12, but only needs to correspond to the number of corresponding grid feet 412.

[0052] Such an insertion slot 5021 setting is more conducive to the protection of the end head part 4120 of the grid foot 412 and the formation of a connection between the arc separation piece 500 and the arc extinguishing grid 410, facilitating the assembly of the arc separation piece 500.

[0053] Each of the grid feet 412 comprises a first surface 412a, a tip surface 412b, and a second surface 412c, the first surface 412a and the second surface 412c being connected by the tip surface 412b. Of course, the first surface 412a and the second surface 412c here are not completely flat surfaces. For example, the first surface 412a is the outer surface of the arc extinguishing grid 410, which has a concave-convex structure to be clamped with the arc extinguishing cover 420.

[0054] The second surface 412c is the surface forming the arc extinguishing groove 413, that is, the second surfaces 412c of the two grid feet 412 are connected to form the arc extinguishing groove 413. For the slot 5021, it does not completely cover the tip portion 4120 of the grid feet 412, but covers the connection between the tip surface 412b and the second surface 412c, so as to shield the tip portion 4120 of the grid feet 412. Here, the part of the tip surface 412b outside the slot 5021 is the excess tip surface 412b inside the slot 5021. With such a structure, the guide portion 502 of the arc separation piece 500 does not need to be made very large, and the tip portion 4120 of the grid feet 412 can be protected.

[0055] For the slot 5021, one of the slot walls is a stop wall 5021a, which is in abutment with the tip surface 412b. Such a matching relationship makes the assembly of the arc separation piece 500 and the arc extinguishing grid 410 more convenient. A slight push until it cannot be pushed any more means that it has been assembled in place.

[0056] Since the shape of the arc extinguishing groove 413 is various, that is, the shape of the second surface 412c is various, for example, a single inclined surface, for example, a plurality of connected inclined surfaces (inclined surfaces with different slopes are connected), for example, an arc surface structure, for example, a combination of an inclined surface and an arc surface. Therefore, the shape of the part of the second surface 412c inside the slot 5021 is also adaptive, for example, an inclined surface or an arc surface or two inclined surfaces with different slopes and connected in sequence or a combination of an inclined surface and an arc surface. In this embodiment, two inclined surfaces with different slopes and connected in sequence are adopted.

[0057] The number of the magnetic conductive plates 600 is two, and the magnetic conductive plates 600 here are iron sheets. During breaking, the iron sheets generate a magnetic field due to the action of the arc. The magnetic field force of the magnetic field acts on the arc, so that the arc is stretched towards the direction of the arc extinguishing groove 413, which is beneficial to the extinction of the arc.

[0058] The installation groove 510 is provided on the surface of each arc separation piece 500 away from the arc extinguishing region 102, and the magnetic conducting plate 600 is fixed in each installation groove 510. The cooperation between the magnetic conducting plate 600 and the installation groove 510 is an interference fit. There are many ways of interference fit, and the interference fit will be conducive to the stable installation of the magnetic conducting plate 600.

[0059] As shown in the drawings, Figures 6-7 In the present embodiment, the installation groove 510 includes a groove bottom 511 and a side wall 512 surrounding the groove bottom 511, and the side wall 512 is provided with a convex point 513. Here, there are three side walls 512 with convex points 513, so that when the magnetic conducting plate 600 is installed, the interference fit between the side surface of the magnetic conducting plate 600 and the convex point 513 can be formed. Of course, according to the actual shape of the installation groove 510, more or fewer side walls 512 can be provided with convex points 513 in this embodiment.

[0060] As shown in the drawings, Figure 8 In the present embodiment, the installation groove 510 has a positioning column 514, and the number of the positioning column 514 is three. Six convex points 513 are provided on the arc-shaped side surface of each positioning column 514. The magnetic conducting plate 600 is provided with three positioning holes 610, and the three positioning holes 610 are respectively sleeved on the three positioning columns 514. The interference fit is formed by the extrusion between the hole wall of the positioning hole 610 and the convex point 513. Of course, the number of the positioning column 514, the convex point 513 and the positioning hole 610 can also be in other ways in this embodiment.

[0061] The rated current of the above-mentioned small circuit breaker is 8A-125A. Of course, the arc extinguishing structure can also be applied to small leakage circuit breakers or small reclosing circuit breakers in addition to the above-mentioned small circuit breakers in the air switch.

[0062] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0063] Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary, and are not to be interpreted as limiting the present application, and it is intended that changes, modifications, substitutions and variations of the above embodiments can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. An arc extinguishing system of a miniature circuit breaker, comprising an arc extinguishing chamber, an arc separation piece and a magnetic conducting plate; the arc extinguishing chamber comprises at least two arc extinguishing grid plates, each of which is stacked in sequence along a first direction; each arc extinguishing grid plate is provided with two grid feet, and an arc extinguishing groove is formed between the two grid feet, and the opening of the arc extinguishing groove of the arc extinguishing grid plate faces a breaking area; characterized in that: The material of the arc separation piece is a gas generating material, the number of the arc separation piece is two, and the two arc separation pieces are arranged on the two sides of the breaking area and correspond to the two grid feet of the same arc-extinguishing grid piece respectively; the arc separation piece has a guide part, and the guide part extends into the arc-extinguishing groove and shields the end part of the corresponding grid foot; The number of the magnetic conductive plate is two, and the magnetic conductive plate is fixed on the surface of the two arc separation pieces away from the breaking area.

2. A small circuit breaker arc quenching system according to claim 1, characterized in that: The arc separation piece further comprises a main body part, the guide part is connected to one end of the main body part close to the arc-extinguishing grid piece, the guide part is inclined towards the inside of the arc-extinguishing groove, and the guide part forms an obtuse angle with the main body part.

3. A small circuit breaker arc quenching system according to claim 2, characterized in that: The distance between the guide parts of the two arc separation pieces gradually decreases from one end close to the main body part to one end away from the main body part.

4. A small circuit breaker arc quenching system according to claim 1 or 2, characterized in that: The guide part is provided with a slot adapted to the number of grid feet, and the end part of the grid foot is inserted into the slot.

5. A small circuit breaker arc quenching system according to claim 4, characterized in that: The grid foot comprises a first surface, an end face and a second surface, the first surface and the second surface are connected through the end face; the second surfaces of the two grid feet are connected, and together form the arc-extinguishing groove; the connection between the end face and the second surface is inserted into the slot, and the part of the end face outside the slot is redundant compared with the part of the end face inside the slot.

6. A small circuit breaker arc quenching system according to claim 5, characterized in that: One of the slot walls of the slot is a stop wall, and the stop wall is in abutment with the end face.

7. A small circuit breaker arc quenching system according to claim 5, characterized in that: The part of the second surface inside the slot is a bevel or an arc surface or a combination of two bevels with different slopes and connected in sequence.

8. A small circuit breaker arc quenching system according to claim 1, characterized in that: The surface of the arc separation piece away from the breaking area is provided with a mounting groove, and the magnetic conductive plate is in interference fit with the mounting groove.

9. A small circuit breaker arc quenching system according to claim 8, characterized in that: The mounting groove comprises a groove bottom and a side wall surrounding the groove bottom, the side wall is provided with a convex point, and the side surface of the magnetic conductive plate is in interference fit with the convex point. Alternatively, the mounting groove has a positioning column, the arc-shaped side surface of the positioning column is provided with a convex point, and the magnetic conductive plate is provided with a positioning hole adapted to the positioning column, and the hole wall of the positioning hole is in interference fit with the convex point.

10. A miniature circuit breaker comprising at least one pole circuit breaker unit, each pole circuit breaker unit having a circuit breaker housing, an operating mechanism and movable and stationary contacts; characterized in that: Each pole circuit breaker unit has an arc-extinguishing system of a small circuit breaker as claimed in any one of claims 1-9.

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