Molded case circuit breaker

Abstract

A molded case circuit breaker comprises an arc extinguishing assembly, the arc extinguishing assembly comprises two oppositely arranged side plates and a plurality of arc extinguishing sheets installed between the two side plates, each arc extinguishing sheet comprises a middle communication part and extension ends on the two sides, a U-shaped gap is formed between the extension ends, a first housing is arranged between the side plates, and a second housing is arranged between the side plates. The first cover shell comprises a first vertical cover plate and a first transverse cover plate, the first vertical cover plate is arranged on the lower portions of the front sides of the two side plates and forms a lower inserting opening, the lower inserting opening is matched with the lower portion of the U-shaped notch, the first vertical cover plate further forms first inner plates on the two sides of the lower inserting opening, and the first inner plates are matched with the corresponding side plates to cover the front end of the extending end of the lower portion. Positioning baffles are further arranged on the outer sides, relative to the corresponding first inner plates, of the first vertical cover plates, positioning of the corresponding side plates is achieved through the positioning baffles, and the first transverse cover plate is arranged corresponding to the bottoms of the side plates and is a convex plate. The arc-isolating switch is simple in structure, convenient and reliable to assemble, safe to use and good in arc-isolating effect.

Description

Technical Field

[0001] The utility model relates to the technical field of low-voltage electrical appliances, in particular to a molded case circuit breaker. Background Art

[0002] A molded case circuit breaker is also known as a device type circuit breaker. All parts are sealed in a plastic housing, and auxiliary contacts, under-voltage release devices, shunt release devices, etc. mostly adopt modularization. A molded case circuit breaker usually includes a contact system, an arc extinguishing system, an operating mechanism, a tripping mechanism, an overload protection system, a short-circuit protection system, etc. In the existing molded case circuit breaker, an arc isolation member is arranged on the arc extinguishing chamber to prevent metal particles melted by the arc from flying out of the arc extinguishing chamber and entering other mechanisms of the molded case circuit breaker. The arc extinguishing chamber includes an upper arc extinguishing grid, a middle arc extinguishing grid and a lower arc extinguishing grid. Left and right arc isolation plates are arranged on both sides of the arc extinguishing grid, and an arc extinguishing cover is arranged between the left and right arc isolation plates. The arc isolation cover on the arc extinguishing chamber on the market is composed of 3 parts (left arc isolation cover a, right arc isolation cover b and 7-shaped arc isolation cover c). As Figure 1 shown, the two side arc isolation covers a and b on both sides are hot riveted, and then a "7"-shaped arc isolation cover is added on it. The hot riveting process is complex and is easily detached and jammed with the moving contact, resulting in the product being unable to close. Summary of the Utility Model

[0003] Aiming at the above-mentioned disadvantages of the existing technology, the purpose of the utility model is to provide a molded case circuit breaker with simple structure, convenient and reliable assembly, safe use and good arc isolation effect.

[0004] The technical solution adopted by the utility model to solve its technical problems is that a molded case circuit breaker includes an arc extinguishing component installed in a receiving groove of a bottom case. The arc extinguishing component includes two oppositely arranged side plates and a plurality of arc extinguishing sheets arranged at a certain inclination interval between the two side plates. The arc extinguishing sheet includes a communication part in the middle and extending ends on both sides. A U-shaped notch is formed between the extending ends. A first cover shell is arranged between the side plates. The first cover shell includes a first vertical cover plate and a first horizontal cover plate. The first vertical cover plate is arranged at the lower part of the front side of the two side plates to form a lower socket. The lower socket cooperates with the lower part of the U-shaped notch. First inner plates are further formed on both sides of the first vertical cover plate relative to the lower socket. The first inner plates cooperate with the corresponding side plates to cover the front ends of the lower extending ends. Positioning baffles are respectively arranged on the outer sides of the corresponding first inner plates of the first vertical cover plate. The positioning baffles form positioning of the corresponding side plates. The first horizontal cover plate corresponds to the bottom of the side plates and is set as a convex plate, and the lower ends of the positioning baffles all extend to both sides of the convex first horizontal cover plate.

[0005] Advantages of adopting the above technical solution: Since the first cover shell adopts the structure of the first vertical cover plate and the first horizontal cover plate, and is integrally formed into a single component, and the first inner plate and the positioning baffle are respectively formed on both sides of the lower notch of the corresponding U-shaped notch on the first vertical cover plate. During installation, first fix multiple arc extinguishing sheets to the side plates on both sides through jigs, which is a step that existed before. Then, the two side plates are respectively installed vertically along the first vertical cover plate through the channels formed by the first inner plate and the positioning baffle arranged on the left and right. After being installed in place, the front end of the lower extension end will be covered by the first inner plate, thus being separated from the moving contact. In this way, it can prevent the molten metal particles generated during the circuit breaker breaking from cooling and depositing in the gap between the lower extension end and the moving contact. At the same time, the positioning baffle also prevents the moving contact from contacting the first inner plate, avoiding the melting of the first inner plate due to the overheating of the moving contact after the circuit breaker breaks. At the same time, the first horizontal cover plate is set as a convex plate to better form a fitting limit with the side plate. The above structural design of the first cover shell is convenient and reliable in the assembly method with the side plate, which not only solves the problem that the hot riveting process will fall off, making it safer to use, but also saves the cost and assembly time of 2 parts. At the same time, the arc isolation effect is also good, and it also ensures the safe opening and closing operation of the moving contact.

[0006] Further, a second cover shell is also provided between the side plates. The second cover shell includes a second vertical cover plate and a second horizontal cover plate. The second vertical cover plate is arranged at the upper front side of the two side plates and forms an upper socket. The upper socket cooperates with the upper part of the U-shaped notch. The second vertical cover plate also forms second inner plates on both sides of the upper socket. The second inner plates cooperate with the corresponding side plates to cover the front end of the upper extension end. The second horizontal cover plate is arranged corresponding to the top of the side plates. There are clamping blocks and clamping grooves between both sides of the second horizontal cover plate and the top of the corresponding side plates.

[0007] Advantages of adopting the above technical solution: By providing a second cover shell composed of a second vertical cover plate and a second horizontal cover plate, and being integrally formed into a single component, and forming second inner plates on both sides of the upper notch of the corresponding U-shaped notch on the second vertical cover plate, and also arranging clamping blocks and clamping grooves between the second horizontal cover plate and the top of the side plates. After the arc extinguishing component is installed on the first cover shell, then the second horizontal cover plate is clamped to the side plates. After being installed in place, the front end of the upper extension end will be covered by the second inner plates, thus being separated from the moving contact. In this way, it can prevent the molten metal particles generated during the circuit breaker breaking from cooling and depositing in the gap between the upper extension end and the moving contact. The above structural design of the second cover shell is simple and reasonable, and also makes it safer to use.

[0008] Further, the arc extinguishing component further includes an upper arc leading sheet and a lower arc leading sheet respectively located above and below the multiple arc extinguishing sheets. The upper arc leading sheet has an upper arc leading foot that cooperates with the U-shaped notch. The lower arc leading sheet has a lower arc leading foot that cooperates with the U-shaped notch.

[0009] Advantages of adopting the above technical solution: By providing an upper arcing piece and a lower arcing piece, and respectively providing an upper arcing foot and a lower arcing foot that cooperate with the U-shaped notch on the upper arcing piece and the lower arcing piece, the arcs generated at the bottom and the top can be guided more fully and precisely into the arc extinguishing chamber, so as to achieve the purpose of efficient arc extinguishing, and the structural design is reasonable.

[0010] Further, a first positioning portion is vertically provided on the outer side wall of the first vertical cover plate, and a corresponding second positioning portion is provided in the receiving groove of the bottom case. The first positioning portion cooperates with the second positioning portion to position and install the arc extinguishing assembly in the receiving groove of the bottom case.

[0011] Advantages of adopting the above technical solution: Through the cooperation of the first positioning portion and the second positioning portion, the position of the arc extinguishing assembly in the receiving groove of the bottom case is limited, so that the cooperation between the arc extinguishing assembly and the moving contact is more precise, the use is safer, and at the same time, the installation of the arc extinguishing assembly is also convenient.

[0012] Further, an inner arc dividing piece and an outer arc dividing piece are also installed in the receiving groove of the bottom case at the rear side of the arc extinguishing assembly. The inner arc dividing piece and the outer arc dividing piece are attached to each other. A plurality of arc extinguishing through grooves are spaced and penetrated through the inner arc dividing piece. Cutting grooves are formed on the mounting feet on both sides of the outer arc dividing piece to make the outer arc dividing piece elastic.

[0013] Advantages of adopting the above technical solution: Through the cooperation of the inner arc dividing piece with arc extinguishing through grooves and the outer arc dividing piece with cutting grooves on the pins, the purpose of multi-directional arc division is achieved, so that the arc is less likely to splash into other mechanisms of the circuit breaker, thereby playing a role in preventing partial failure of the mechanism during the breaking process of the circuit breaker, and the safety is better.

[0014] Further, a first arc-shaped baffle is formed at the bottom of the lower socket, and a second arc-shaped baffle is formed at the other end of the first horizontal cover plate.

[0015] Advantages of adopting the above technical solution: The first arc-shaped baffle and the second arc-shaped baffle are used to prevent the circuit from being broken down at the shortest position during conduction, avoid the occurrence of arcing phenomenon, and make the use of the arc extinguishing chamber safer.

[0016] Further, the molded case circuit breaker further includes a static contact installed in the receiving groove of the bottom case. The contact end of the static contact on the side of the arc extinguishing piece is provided as a bending portion, and a static contact point that cooperates with the moving contact is provided on the bending portion. Hollow portions are provided on both the first horizontal cover plate and the static contact. A supporting column is also provided in the receiving groove of the bottom case. The supporting column abuts against the bottom of the bending portion through the hollow portion, and the lower ends of the first inner plates are all provided as arc-shaped surfaces that cooperate with the upper surface of the bending portion.

[0017] Advantages of adopting the above technical solution: The contact end of the static contact on the arc extinguishing piece side is set as a bending part to carry the static contact point, enabling the static contact point to contact the external moving contact more fittingly. Moreover, a stable support for the bending part is formed by the supporting column and the lower end of the first inner plate, thereby ensuring the actual contact area of the contact system, and thus the service life and reliability are higher.

[0018] Furthermore, an avoidance groove for cooperating with the static contact is also provided at the bottom of the first horizontal cover plate.

[0019] Advantages of adopting the above technical solution: The setting of the avoidance groove effectively reduces the overall height on the premise of ensuring the arc isolation effect. Brief Description of the Drawings

[0020] Figure 1 is the overall structural schematic diagram of the present utility model;

[0021] Figure 2 is the partial structural exploded schematic diagram of the present utility model;

[0022] Figure 3 is the partial structural schematic diagram of the present utility model;

[0023] Figure 4 is the structural schematic diagram of the first cover shell of the present utility model;

[0024] Figure 5 is another view of the structural schematic diagram of the first cover shell of the present utility model;

[0025] Figure 6 is the structural schematic diagram of the second cover shell of the present utility model;

[0026] Figure 7 is the structural schematic diagram of the static contact of the present utility model;

[0027] Figure 8 is the structural schematic diagram of the bottom shell of the present utility model.

[0028] In the figures: 1-bottom shell, 2-side plate, 3-arc extinguishing piece, 4-communication part, 5-extension end, 6-U-shaped notch, 7-first cover shell, 8-first vertical cover plate, 9-first horizontal cover plate, 10-lower socket, 11-first inner plate, 12-positioning baffle, 13-second cover shell, 14-second vertical cover plate, 15-second horizontal cover plate, 16-upper socket, 17-second inner plate, 18-upper arcing piece, 19-lower arcing piece, 20-upper arcing foot, 21-lower arcing foot, 22-first positioning part, 23-second positioning part, 24-inner arc isolation piece, 25-outer arc isolation piece, 26-arc extinguishing through groove, 27-cutting groove, 28-first arc-shaped baffle, 29-second arc-shaped baffle, 30-static contact, 31-bending part, 32-static contact point, 33-hollow part, 34-supporting column, 35-avoidance groove. Detailed implementation manners

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention and / or the prior art, the following will describe the specific implementation manners of the present invention with reference to the drawings. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, and other implementation manners can also be obtained. Additionally, the terms related to directions only represent the relative positional relationships between components, rather than absolute positional relationships.

[0030] Please refer to Figures 1 to 8As shown in the figure, a molded case circuit breaker includes an arc extinguishing component installed in a receiving groove of a bottom case 1. The arc extinguishing component includes two oppositely arranged side plates 2 and a plurality of arc extinguishing plates 3 arranged at a certain inclination interval between the two side plates 2. The arc extinguishing plate 3 includes a connecting portion 4 in the middle and extending ends 5 on both sides. A U-shaped notch 6 is formed between the extending ends 5. A first cover 7 is further provided between the side plates 2. The first cover 7 includes a first vertical cover plate 8 and a first horizontal cover plate 9. The first vertical cover plate 8 is arranged at the lower front side of the two side plates 2 and forms a lower socket 10. The lower socket 10 cooperates with the lower part of the U-shaped notch 6 to realize the effective rotation of the moving contact. The first vertical cover plate 8 further forms first inner plates 11 on both sides of the lower socket 10. The first inner plates 11 cooperate with the corresponding side plates 2 to cover the front ends of the lower extending ends 5. Positioning baffles 12 are respectively provided on the outer sides of the first vertical cover plate 8 relative to the corresponding first inner plates 11. The positioning baffles 12 form the positioning of the corresponding side plates 2. More specifically, the positioning baffles 12 will form a channel for the corresponding side plates 2 to be vertically installed on the first vertical cover plate 8 with the first inner plates 11. The first horizontal cover plate 9 is arranged corresponding to the bottom of the side plate 2 and is set as a convex plate, and the lower ends of the positioning baffles 12 both extend to both sides of the convex first horizontal cover plate 9. Since the first cover 7 adopts the structure of the first vertical cover plate 8 and the first horizontal cover plate 9 and is integrally formed into a single component, and the first inner plates 11 and the positioning baffles 12 are respectively formed on both sides of the lower notch corresponding to the U-shaped notch 6 on the first vertical cover plate 8. During installation, first, a plurality of arc extinguishing plates 3 are fixed to the two side plates 2 through a fixture, which was available before. Then, the two side plates 2 are respectively vertically installed along the first vertical cover plate 8 through the channels formed by the first inner plates 11 and the positioning baffles 12 arranged on the left and right. After the installation is in place, the front ends of the lower extending ends 5 will be covered by the first inner plates 11, thus being separated from the moving contact. In this way, it can prevent the molten metal particles generated by the circuit breaker breaking from cooling and depositing in the gap between the lower extending ends 5 and the moving contact. At the same time, the positioning baffles 12 also prevent the moving contact from contacting the first inner plates 11, avoiding the situation that the moving contact temperature is too high after the circuit breaker breaks and melts the first inner plates. At the same time, the first horizontal cover plate 9 is also set as a convex plate to better form a matching limit with the side plates 2. The above structural design of the first cover 7 and the assembly method with the side plates 2 are convenient and reliable. It not only solves the problem that the hot riveting process will fall off and is safer to use, but also saves the cost and assembly time of two parts. At the same time, the arc isolation effect is good, and it also ensures the safe opening and closing operation of the moving contact.

[0031] In this embodiment, a second housing 13 is further provided between the side plates 2. The second housing 13 includes a second vertical housing plate 14 and a second horizontal housing plate 15. The second vertical housing plate 14 is disposed at the upper part of the front side of the two side plates 2 and forms an upper socket 16. The upper socket 16 cooperates with the upper part of the U-shaped notch 6 to enable the effective rotation of the moving contact. The second vertical housing plate 14 further forms second inner plates 17 on both sides of the upper socket 16. The second inner plates 17 cooperate with the corresponding side plates 2 to cover the front end of the upper extension end 5. The second horizontal housing plate 15 is disposed corresponding to the top of the side plates 2. There are clamping blocks and clamping grooves between both sides of the second horizontal housing plate 15 and the top of the corresponding side plates 2. By providing the second housing 13 composed of the second vertical housing plate 14 and the second horizontal housing plate 15, and integrally forming it into a single component, and forming second inner plates 17 on both sides of the upper notch 16 corresponding to the U-shaped notch 6 on the second vertical housing plate 14, and also providing clamping blocks and clamping grooves between the second horizontal housing plate 15 and the top of the side plates 2, after the arc extinguishing component is installed on the first housing 7, the second horizontal housing plate 15 is then clamped to the side plates 2. And after being installed in place, the front end of the upper extension end 5 will be covered by the second inner plates 17, thereby being separated from the moving contact. In this way, it can prevent the molten metal particles generated by the breaking of the circuit breaker from cooling and depositing in the gap between the upper extension end 5 and the moving contact. The above structural design of the second housing 13 is simple and reasonable, and also makes it safer to use.

[0032] In this embodiment, the arc extinguishing component further includes an upper arcing piece 18 and a lower arcing piece 19 respectively located above and below the plurality of arc extinguishing plates 3. The upper arcing piece 18 has an upper arcing leg 20 that cooperates with the U-shaped notch 6, and the lower arcing piece 19 has a lower arcing leg 21 that cooperates with the U-shaped notch 6. By providing the upper arcing piece 18 and the lower arcing piece 19, and respectively providing the upper arcing leg 20 and the lower arcing leg 21 that cooperate with the U-shaped notch 6 on the upper arcing piece 18 and the lower arcing piece 19, it can guide the arcs generated at the bottom and the top to enter the arc extinguishing chamber more fully and precisely, so as to achieve the purpose of efficient arc extinguishing, and the structural design is reasonable.

[0033] In this embodiment, a first positioning portion 22 is vertically provided on the outer side wall of the first vertical housing plate 8, and a corresponding second positioning portion 23 is provided in the receiving groove of the bottom case 1. The first positioning portion 22 cooperates with the second positioning portion 23 to position and install the arc extinguishing component in the receiving groove of the bottom case 1. The first positioning portion 22 and the second positioning portion 23 can be grooves, convex columns or convex columns, grooves. Through the cooperation of the first positioning portion 22 and the second positioning portion 23, the position of the arc extinguishing component in the receiving groove of the bottom case 1 is limited, so that the cooperation between the arc extinguishing component and the moving contact is more precise, the use is safer, and at the same time, the installation of the arc extinguishing component is also convenient.

[0034] In this embodiment, an inner arc separator 24 and an outer arc separator 25 are further installed in the receiving groove of the bottom case 1 at the rear side of the arc extinguishing assembly. The inner arc separator 24 and the outer arc separator 25 are fitted together. A plurality of arc extinguishing through grooves 26 are spaced through the inner arc separator 24. Cutting grooves 27 for making the outer arc separator 25 elastic are formed on both mounting feet of the outer arc separator 25. Through the cooperation of the inner arc separator 24 with the arc extinguishing through grooves 26 and the outer arc separator 25 with the cutting grooves 27 on the pins, and in combination with the first cover 7 and the second cover 13, the purpose of multi-directional arc separation is achieved, making it more difficult for the arc to splash into other mechanisms of the circuit breaker, thereby playing a role in preventing the mechanism part from failing during the breaking process of the circuit breaker, and the safety is better.

[0035] In this embodiment, a first arc-shaped baffle 28 is formed at the bottom of the lower socket 10, and a second arc-shaped baffle 29 is formed at the other end of the first horizontal cover plate 9. The first arc-shaped baffle 28 and the second arc-shaped baffle 29 are used to prevent the shortest position breakdown from occurring during the conduction of the circuit, avoid the occurrence of arcing phenomenon, and make the use of the arc extinguishing chamber safer.

[0036] In this embodiment, the molded case circuit breaker further includes a static contact 30 installed in the receiving groove of the bottom case 1. The contact end of the static contact 30 on the side of the arc extinguishing piece 3 is provided as a bent portion 31. A static contact point 32 for cooperating with the moving contact is provided on the bent portion 31. Hollow portions 33 are provided on both the first horizontal cover plate 9 and the static contact 30. A supporting column 34 is further provided in the receiving groove of the bottom case 1. The supporting column 34 abuts against the bottom of the bent portion 31 through the hollow portion 33. And the lower ends of the first inner plates 11 are all provided as arc-shaped surfaces for cooperating with the upper surface of the bent portion 31. The contact end of the static contact 30 on the side of the arc extinguishing piece 3 is provided as the bent portion 31 to carry the static contact point 32, so that the static contact point 32 can contact the external moving contact more fittingly. Also, a stable support for the bent portion 31 is formed by the supporting column 34 and the lower ends of the first inner plates 11, thereby ensuring the actual contact area of the contact system, so the service life and reliability are higher. It should be noted that the second arc-shaped baffle 29 is arranged between the wiring end of the static contact 30 and the arc extinguishing piece 3 at the bottom.

[0037] In this embodiment, an avoidance groove 35 for cooperating with the static contact 30 is further provided at the bottom of the first horizontal cover plate 9. The setting of the avoidance groove 35 effectively reduces the overall height on the premise of ensuring the arc separation effect.

[0038] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A plastic case circuit breaker, comprising an arc extinguishing component installed in a receiving groove of a bottom case (1), the arc extinguishing component including two oppositely arranged side plates (2), and a plurality of arc extinguishing plates (3) arranged at an inclined interval between the two side plates (2). The arc extinguishing plate (3) includes a communicating portion (4) in the middle and extending ends (5) on both sides. A U-shaped notch (6) is formed between the extending ends (5). It is characterized in that: a first cover shell (7) is provided between the side plates (2). The first cover shell (7) includes a first vertical cover plate (8) and a first horizontal cover plate (9). The first vertical cover plate (8) is arranged at the lower front side of the two side plates (2) and forms a lower socket (10). The lower socket (10) cooperates with the lower part of the U-shaped notch (6). The first vertical cover plate (8) further forms first inner plates (11) on both sides relative to the lower socket (10). The first inner plates (11) cooperate with the corresponding side plates (2) to cover the front ends of the lower extending ends (5). Positioning baffles (12) are provided on the outer sides of the first vertical cover plate (8) corresponding to the first inner plates (11). The positioning baffles (12) form positioning for the corresponding side plates (2). The first horizontal cover plate (9) is arranged corresponding to the bottom of the side plates (2) and is a convex plate, and the lower ends of the positioning baffles (12) extend to both sides of the convex first horizontal cover plate (9).

2. A molded case circuit breaker according to claim 1, characterized in that: A second cover shell (13) is further provided between the side plates (2). The second cover shell (13) includes a second vertical cover plate (14) and a second horizontal cover plate (15). The second vertical cover plate (14) is arranged at the upper front side of the two side plates (2) and forms an upper socket (16). The upper socket (16) cooperates with the upper part of the U-shaped notch (6). The second vertical cover plate (14) further forms second inner plates (17) on both sides of the upper socket (16). The second inner plates (17) cooperate with the corresponding side plates (2) to cover the front ends of the upper extending ends (5). The second horizontal cover plate (15) is arranged corresponding to the top of the side plates (2). A clamping block and a clamping groove are provided between both sides of the second horizontal cover plate (15) and the top of the corresponding side plates (2).

3. A molded case circuit breaker according to claim 2, characterized in that: The arc extinguishing component further includes an upper arcing plate (18) and a lower arcing plate (19) respectively located above and below the plurality of arc extinguishing plates (3). The upper arcing plate (18) has an upper arcing foot (20) that cooperates with the U-shaped notch (6). The lower arcing plate (19) has a lower arcing foot (21) that cooperates with the U-shaped notch (6).

4. A molded case circuit breaker according to claim 1, characterized in that: A first positioning portion (22) is vertically provided on the outer side wall of the first vertical cover plate (8). A corresponding second positioning portion (23) is provided in the receiving groove of the bottom case (1). The first positioning portion (22) cooperates with the second positioning portion (23) to position and install the arc extinguishing component in the receiving groove of the bottom case (1).

5. A molded case circuit breaker according to claim 1, characterized in that: An inner arc-isolating plate (24) and an outer arc-isolating plate (25) are also installed in the receiving groove of the bottom shell (1) at the rear side of the arc-extinguishing assembly. The inner arc-isolating plate (24) and the outer arc-isolating plate (25) are fitted together. A plurality of arc-extinguishing through grooves (26) are provided at intervals through the inner arc-isolating plate (24). The mounting feet on both sides of the outer arc-isolating plate (25) are also formed with cutting grooves (27) that allow the outer arc-isolating plate (25) to be elastic.

6. A molded case circuit breaker according to claim 1, characterized in that: A first arc-shaped baffle (28) is formed at the bottom of the lower insertion opening (10), and a second arc-shaped baffle (29) is formed on the other end of the first transverse cover plate (9).

7. A molded case circuit breaker according to any one of claims 1-6, characterized in that: The molded case circuit breaker also includes a stationary contact (30) installed in the receiving groove of the bottom shell (1), and one end of the stationary contact (30) on the side of the arc extinguishing piece (3) is set as a bent portion (31), and the bent portion (31) is provided with a stationary contact (32) that matches the moving contact, and the first transverse cover plate (9) and the stationary contact (30) are both provided with a hollow portion (33). A support column (34) is also provided in the receiving groove of the bottom shell (1), and the support column (34) is supported on the bottom of the bent portion (31) through the hollow portion (33), and the lower end of the first inner plate (11) is set as an arc surface that matches the upper surface of the bent portion (31).

8. A molded case circuit breaker according to claim 7, characterized in that: The bottom of the first transverse cover plate (9) is also provided with an escape groove (35) matching the static contact (30).

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