Arc extinguishing chamber nozzle connecting structure and arc extinguishing chamber

Abstract

The application relates to the technical field of circuit breakers, in particular to an arc-extinguishing chamber nozzle connecting structure and an arc-extinguishing chamber. The arc-extinguishing chamber nozzle connecting structure comprises a small nozzle and a mounting base, the small nozzle and the mounting base are connected through a threaded connecting structure, the small nozzle and the mounting base are connected in the axial direction through a hook-and-slot matching structure formed by a hook arranged on one of the small nozzle and the mounting base and a slot arranged on the other, the hook and the slot are strongly matched, when the small nozzle is screwed onto the mounting base through the threaded connecting structure, the hook is forcedly squeezed into the slot under the spiral driving action of the matched threaded section. In the process of screwing the small nozzle onto the mounting base, the hook is forcedly squeezed into the slot under the driving action of the matched threaded section, so that the small nozzle and the mounting base are connected in the axial direction, thereby preventing the small nozzle from moving in the axial direction due to heat, keeping the threaded connection between the small nozzle and the mounting base in an effective pre-tightening state, and avoiding loosening and falling of the small nozzle.

Description

Technical Field

[0001] This invention relates to the field of circuit breaker technology, and in particular to an arc-extinguishing chamber nozzle connection structure and an arc-extinguishing chamber. Background Technology

[0002] The existing structure of a compressed air arc-extinguishing chamber is typically as shown in Chinese invention patent application CN102306590A, comprising a compressed air cylinder, a stationary contact module, and a moving contact module. The moving contact module cooperates with the stationary contact module and achieves contact connection or disconnection through relative movement. The stationary contact module includes a stationary main contact and a stationary arc contact, while the moving contact module includes a moving main contact, a moving arc contact, a large nozzle, and a small nozzle. A front seat is provided at the front end of the compressed air cylinder as a conductive connection seat, and the moving main contact, moving arc contact, large nozzle, and small nozzle are all fixedly connected to the conductive connection seat. When the arc-extinguishing chamber is closed, the moving arc contact and the stationary arc contact engage before the moving main contact and the stationary main contact and withstand arc erosion. When the arc-extinguishing chamber is opened, the moving arc contact and the stationary arc contact disengage after the moving main contact and the stationary main contact and withstand arc erosion. The large nozzle and the small nozzle are used to guide the flow of arc-extinguishing gas, thereby extinguishing the arc.

[0003] In the arc-extinguishing chamber structures disclosed in the aforementioned patent applications, the small nozzle is typically connected to the conductive connector via a threaded connection. While other existing technologies may connect the small nozzle to the moving arc contact, which is then fixedly connected to the conductive connector, both methods pose a risk of connection failure due to the harsh operating environment of the arc-extinguishing chamber. The connection between the small nozzle and the mounting base (composed of the moving arc contact and / or the conductive connector) is solely threaded. This is particularly problematic in high-speed circuit breakers with large breaking capacities. The high opening speed and high arc energy generate significant heat during breaking, causing the small nozzle to expand axially, potentially leading to threaded connection failure, loosening or even detachment of the nozzle. This negatively impacts the arc-extinguishing effect and even the normal breaking of the arc-extinguishing chamber, ultimately resulting in the circuit breaker's failure to interrupt fault currents. Summary of the Invention

[0004] The purpose of this invention is to provide a nozzle connection structure for an arc-extinguishing chamber to solve the problem that in the prior art, the small nozzle is only connected to the mounting base by a thread due to thermal expansion, which poses a risk of connection failure. The invention also aims to provide an arc-extinguishing chamber to solve the problem that in existing arc-extinguishing chambers, the small nozzle is only connected to the mounting base by a thread, which easily leads to axial expansion of the small nozzle after thermal expansion, resulting in connection failure and affecting the arc-extinguishing effect and the reliability of the circuit breaker's breaking current.

[0005] To achieve the above objectives, the arc-extinguishing chamber nozzle connection structure of the present invention adopts the following technical solution: An arc-extinguishing chamber nozzle connection structure includes a small nozzle and a mounting base. The small nozzle and the mounting base are connected by a threaded connection structure. The small nozzle and the mounting base are axially anti-detached by a hook-and-groove mating structure consisting of a hook on one side and a groove on the other side. The hook and groove are forcibly mated. When the small nozzle is screwed onto the mounting base through the threaded connection structure, the hook is forcibly squeezed into the groove under the helical drive of the mating thread section.

[0006] Beneficial effects: This invention proposes an improved arc-extinguishing chamber nozzle connection structure. Based on the existing threaded connection between the small nozzle and the mounting base, a hook is provided on one of the small nozzle and the mounting base, and a groove is provided on the other. During the process of screwing the small nozzle onto the mounting base through the threaded connection structure, the hook is forcibly squeezed into the groove under the driving action of the mating thread section, so that the small nozzle and the mounting base are axially prevented from detaching. This prevents the small nozzle from moving axially due to heat, and keeps the threaded connection between the small nozzle and the mounting base in an effective pre-tight state, avoiding the small nozzle from loosening and falling off.

[0007] Furthermore, the hook-groove mating structure is located on the front side of the threaded connection structure in the direction of screwing.

[0008] Beneficial effects: By placing the hook-groove mating structure on the front side of the screw-in direction of the threaded connection structure, the structure of the small nozzle and the mounting base can be simplified. Moreover, when screwing the small nozzle onto the mounting base, the degree of screwing of the small nozzle can be seen, making it easy to observe whether the hook has been accurately engaged in the groove.

[0009] Furthermore, the hook is stopped and limited by the groove in the axial direction of the small nozzle.

[0010] Beneficial effects: The hook is stopped and limited by the groove in the axial direction of the small nozzle, which can prevent the hook from moving axially in the groove, and further prevent the small nozzle from moving axially and loosening.

[0011] Furthermore, the mounting base includes a conductive connecting seat for connecting the pull rod and the moving main contact, and a moving arc contact fixedly connected to the conductive connecting seat. The threaded section of the base of the threaded connection structure is located on the moving arc contact, and the hook or groove of the hook-groove mating structure is located on the conductive connecting seat.

[0012] Beneficial effects: By setting the hooks or grooves on the mounting base of the base thread section and the hook groove structure on the two components respectively, the processing of each component can be made more convenient. Moreover, the small nozzle is connected to both components at the same time, which can make the fixed connection of the small nozzle more reliable.

[0013] Furthermore, the moving arc contact is threadedly connected to the conductive connection seat.

[0014] Beneficial effects: The moving arc contact is fixedly connected to the small nozzle and the conductive connector respectively through two threaded sections. During production and processing, the pitch and starting end of the two threaded sections cannot be exactly the same. Fixing the moving arc contact to the small nozzle and the conductive connector respectively through two threaded sections can prevent the moving arc contact from loosening and make the connection more reliable.

[0015] Furthermore, the moving arc contact is threadedly connected to the conductive connection seat through the external threaded section of the contact, and the external threaded section of the contact is located in front of the screwing direction of the base threaded section. The base threaded section is located on the outer circumferential surface of the radially convex ring provided on the moving arc contact. One end face of the radially convex ring is stopped and engaged with the conductive connection seat. An inner stop is provided on the inner side of the small nozzle. The inner stop is located behind the screwing direction of the nozzle threaded section on the small nozzle of the threaded connection structure. The other end face of the radially convex ring is stopped and engaged with the inner stop.

[0016] Beneficial effects: By setting a radially convex ring on the moving arc contact, one end face of the radially convex ring is stopped and engaged with the inner baffle on the inner side of the small nozzle, and the other end face is stopped and engaged with the conductive connection seat, which can further prevent the moving arc contact from moving axially, so that the moving arc contact and the conductive connection seat always maintain a reliable threaded connection and prevent the moving arc contact from loosening.

[0017] The arc-extinguishing chamber of this invention adopts the following technical solution: The arc-extinguishing chamber includes a moving contact assembly, a small nozzle of the moving contact assembly, and a mounting base. The small nozzle and the mounting base are connected by a threaded connection structure. The small nozzle and the mounting base are axially anti-detached by a hook-and-groove mating structure consisting of a hook on one side and a groove on the other side. The hook and groove are forcibly mated. When the small nozzle is screwed onto the mounting base through the threaded connection structure, the hook is forcibly squeezed into the groove under the helical drive of the mating thread section.

[0018] Beneficial effects: The arc-extinguishing chamber of this invention improves upon existing arc-extinguishing chambers. Building upon the existing threaded connection between the small nozzle and the mounting base, a hook is provided on one of the small nozzles and the mounting base, and a groove is provided on the other. During the screwing of the small nozzle onto the mounting base via the threaded connection structure, the hook is forcibly squeezed into the groove under the driving action of the mating thread section, thus preventing the small nozzle and the mounting base from axially disengaging. This prevents the small nozzle from moving axially due to heat, ensuring that the threaded connection between the small nozzle and the mounting base remains effectively pre-tightened, preventing the small nozzle from loosening and falling off, and guaranteeing the arc-extinguishing capacity of the arc-extinguishing chamber and the reliability of the circuit breaker's breaking current.

[0019] Furthermore, the hook-groove mating structure is located on the front side of the threaded connection structure in the direction of screwing.

[0020] Beneficial effects: By placing the hook-groove mating structure on the front side of the screw-in direction of the threaded connection structure, the structure of the small nozzle and the mounting base can be simplified. Moreover, when screwing the small nozzle onto the mounting base, the degree of screwing of the small nozzle can be seen, making it easy to observe whether the hook has been accurately engaged in the groove.

[0021] Furthermore, the hook is stopped and limited by the groove in the axial direction of the small nozzle.

[0022] Beneficial effects: The hook is stopped and limited by the groove in the axial direction of the small nozzle, which can prevent the hook from moving axially in the groove, and further prevent the small nozzle from moving axially and loosening.

[0023] Furthermore, the mounting base includes a conductive connecting seat for connecting the pull rod and the moving main contact, and a moving arc contact fixedly connected to the conductive connecting seat. The threaded section of the base of the threaded connection structure is located on the moving arc contact, and the hook or groove of the hook-groove mating structure is located on the conductive connecting seat.

[0024] Beneficial effects: By setting the hooks or grooves on the mounting base of the base thread section and the hook groove structure on the two components respectively, the processing of each component can be made more convenient. Moreover, the small nozzle is connected to both components at the same time, which can make the fixed connection of the small nozzle more reliable.

[0025] Furthermore, the moving arc contact is threadedly connected to the conductive connection seat.

[0026] Beneficial effects: The moving arc contact is fixedly connected to the small nozzle and the conductive connector respectively through two threaded sections. During production and processing, the pitch and starting end of the two threaded sections cannot be exactly the same. Fixing the moving arc contact to the small nozzle and the conductive connector respectively through two threaded sections can prevent the moving arc contact from loosening and make the connection more reliable.

[0027] Furthermore, the moving arc contact is threadedly connected to the conductive connection seat through the external threaded section of the contact, and the external threaded section of the contact is located in front of the screwing direction of the base threaded section. The base threaded section is located on the outer circumferential surface of the radially convex ring provided on the moving arc contact. One end face of the radially convex ring is stopped and engaged with the conductive connection seat. An inner stop is provided on the inner side of the small nozzle. The inner stop is located behind the screwing direction of the nozzle threaded section on the small nozzle of the threaded connection structure. The other end face of the radially convex ring is stopped and engaged with the inner stop.

[0028] Beneficial effects: By setting a radially convex ring on the moving arc contact, one end face of the radially convex ring is stopped and engaged with the inner baffle on the inner side of the small nozzle, and the other end face is stopped and engaged with the conductive connection seat, which can further prevent the moving arc contact from moving axially, so that the moving arc contact and the conductive connection seat always maintain a reliable threaded connection and prevent the moving arc contact from loosening.

[0029] Furthermore, the arc-extinguishing chamber also includes a compressor cylinder and a moving main contact. The outer side of the conductive connection seat included in the mounting base has a connecting flange. The moving main contact is fixedly connected to the connecting flange through a threaded connector, and the compressor cylinder is pressed between the moving main contact and the conductive connection seat.

[0030] Beneficial effects: The moving main contact is fixedly connected to the connecting flange of the conductive connection seat through a threaded connector. The pressure cylinder is pressed between the moving main contact and the conductive connection seat, which makes the connection of the moving main contact, the pressure cylinder and the conductive connection seat more convenient and reliable.

[0031] Furthermore, the arc-extinguishing chamber also includes a large nozzle, an inner baffle on the moving main contact, and a clamping flange on the outer side of the large nozzle. When the moving main contact is connected to the conductive connection seat, the clamping flange is pressed and fixed on the conductive connection seat by the inner baffle.

[0032] Beneficial effects: An inner retaining edge is provided on the moving main contact, and a clamping flange is provided on the outside of the large nozzle. The clamping flange on the outside of the large nozzle is pressed against the conductive connector by the inner retaining edge on the moving main contact, thereby pressing the large nozzle between the moving main contact and the conductive connector. The large nozzle is fixed by crimping, which is convenient to install and can effectively prevent the large nozzle from loosening. Attached Figure Description

[0033] Figure 1 This is a partial cross-sectional view of Embodiment 1 of the arc-extinguishing chamber of the present invention; Figure 2 for Figure 1 Cross-sectional view of small and medium-sized nozzles; Figure 3 for Figure 1 Cross-sectional view of the conductive connector; Figure 4 for Figure 1 Enlarged schematic diagram of the connection between the small and medium-sized nozzle, the moving arc contact, and the conductive connector; In the diagram: 1. Small nozzle; 101. Nozzle threaded section; 102. Hook; 103. Groove; 11. Inner baffle; 2. Moving arc contact; 20. Contact external threaded section; 21. Radial outer protruding ring; 22. Base threaded section; 3. Pull rod; 4. Compressed cylinder; 5. Conductive connector; 501. Air passage; 502. Slot; 503. Connector internal threaded section; 504. Hook-shaped ring; 6. Moving main contact; 601. Inner baffle; 7. Large nozzle; 701. Clamping flange. Detailed Implementation

[0034] The present invention adds a hook-groove fit structure to the existing threaded connection between the small nozzle and the mounting base of the arc-extinguishing chamber, so that the small nozzle and the mounting base are axially prevented from detaching. This prevents the small nozzle from moving axially due to thermal expansion, and keeps the threaded connection between the small nozzle and the mounting base in an effective pre-tight state, thus preventing the small nozzle from loosening and falling off.

[0035] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0036] Example 1 of the arc-extinguishing chamber of the present invention: like Figure 1 As shown, the arc-extinguishing chamber includes a stationary contact unit (not shown) and a moving contact unit. The moving contact unit includes a pressure cylinder 4, a moving main contact 6, a moving arc contact 2, a large nozzle 7, a small nozzle 1, and a conductive connection seat 5. The pressure cylinder 4 has a pull rod 3 inside, which is fixedly connected to the conductive connection seat 5. The moving main contact 6 and the conductive connection seat 5 are fixedly connected by screws. Figure 4 As shown, the conductive connector 5 has a connecting flange on its outer side. Screws pass through the connecting flange and the air cylinder 4, and are screwed into the moving main contact 6, pressing the air cylinder 4 between the moving main contact 6 and the conductive connector 5. The moving main contact 6 has an inner flange 601, and the outer side of the large nozzle 7 has a clamping flange 701. The inner flange 601 on the moving main contact 6 presses and fixes the clamping flange 701 on the outer side of the large nozzle 7 onto the conductive connector 5, thus pressing the large nozzle 7 between the moving main contact 6 and the conductive connector 5. The large nozzle 7 is fixed by a crimping method, which is convenient to install and effectively prevents the large nozzle 7 from loosening. The moving arc contact 2 is fixedly connected to the conductive connector 5. The moving arc contact 2 and the conductive connector 5 together form the mounting base. The small nozzle 1 is connected to the moving arc contact 2 by a thread. The small nozzle 1 has a cylindrical structure. A nozzle thread section 101 is provided on the inner surface of the small nozzle 1. A radially protruding ring 21 that is adapted to the nozzle thread section 101 is provided on the outer surface of the moving arc contact 2. The small nozzle 1 is screwed onto the outside of the moving arc contact 2 through a threaded connection structure.

[0037] A radially outwardly opening groove 103 is provided on the outer surface of the small nozzle 1, and a hook 102 is formed on the small nozzle 1, such as... Figure 2 As shown. A slot 502 is provided on the conductive connector 5, as... Figure 3As shown, the hook 102 and the slot 502 form a hook-slot fit structure, ensuring an axially resistant connection between the small nozzle 1 and the conductive connector 5. The hook 102 and slot 502 are forcibly fitted together. When the small nozzle 1 is screwed onto the mounting base via the threaded connection structure, the hook 102 is forcibly squeezed into the slot 502 under the helical drive of the threaded section. The hook-slot fit structure is located at the front of the threaded connection structure in the screwing direction, allowing observation of the screwing degree of the small nozzle 1 when it is screwed onto the mounting base, facilitating the observation of whether the hook 102 has accurately engaged in the slot 502. The hook 102 is stopped and limited by the slot 502 in the axial direction of the small nozzle 1, preventing axial movement of the hook 102 within the slot 502, further preventing axial movement of the small nozzle 1 and preventing it from loosening. While a radially inwardly opening slot 502 is formed on the conductive connector 5, a hook-shaped ring 504 is formed on the front side of the slot 502, such as... Figure 3 As shown, the hook-shaped ring 504 fits perfectly into the groove 103 on the small nozzle 1 during assembly.

[0038] like Figure 3 As shown, the conductive connector 5 has a gas passage 501 around the central through hole for arc-extinguishing gas to pass through. The conductive connector 5 has an internal thread section 503. The moving arc contact 2 is threaded to the conductive connector 5 through the external thread section 20. Figure 4 As shown. The moving arc contact 2 is fixedly connected to the small nozzle 1 and the conductive connecting seat 5 respectively through two threaded sections. During production, the pitch and starting end of the two threaded sections cannot be completely consistent. Fixing the moving arc contact 2 to the small nozzle 1 and the conductive connecting seat 5 respectively through two threaded sections makes the moving arc contact 2 less prone to loosening and the connection more reliable. The external threaded section 20 of the contact is located in front of the screwing direction of the base threaded section 22. The base threaded section 22 is located on the outer circumferential surface of the radially convex ring 21 provided on the moving arc contact 2. One end face of the radially convex ring 21 is stopped and engaged with the conductive connecting seat 5. An inner stop 11 is provided on the inner side of the small nozzle 1. The inner stop 11 is located behind the screwing direction of the nozzle threaded section 101 on the small nozzle 1. The other end face of the radially convex ring 21 is stopped and engaged with the inner stop 11. By setting a radially protruding ring 21 on the moving arc contact 2, one end face of the radially protruding ring 21 is stopped and engaged with the inner baffle 11 inside the small nozzle 1, and the other end face is stopped and engaged with the conductive connection seat 5, which can further prevent the moving arc contact 2 from moving axially, so that the moving arc contact 2 and the conductive connection seat 5 always maintain a reliable threaded connection and prevent the moving arc contact 2 from loosening.

[0039] During assembly, the moving arc contact 2 is first fixed to the conductive connection seat 5 via a threaded connection. Then, a small nozzle 1 is installed on the outside of the moving arc contact 2. When installing the small nozzle 1, the nozzle thread section 101 is first screwed into the external thread of the moving arc contact 2. During the screwing process, the hook 102 at the rear end of the small nozzle 1 contacts the hook-shaped ring 504 at the front end of the conductive connection seat 5. At this time, a certain force is applied to the front end of the small nozzle 1 to continue screwing it in. During this process, the hook 102 at the rear end of the small nozzle 1 is pushed into the groove 502 on the conductive connection seat 5. After the small nozzle 1 is installed, the large nozzle 7 is pressed and fixed using the moving main contact 6. The moving main contact 6, the pressure cylinder 4, and the conductive connection seat 5 are then fixedly connected with screws. An airflow channel for the arc-extinguishing airflow is formed between the large nozzle 7 and the small nozzle 1. This structural design does not change the shape and volume of the airflow channel, thus ensuring that the arc-extinguishing performance of the arc-extinguishing chamber and the breaking current performance of the circuit breaker are not affected.

[0040] The present invention, based on the existing arc-extinguishing chamber with the small nozzle 1 and the moving arc contact 2 threaded connection, adds a hook 102 on the small nozzle 1 and a corresponding slot 502 on the conductive connection seat 5. During the process of screwing the small nozzle 1 onto the moving arc contact 2 through the threaded connection structure, the hook 102 is forcibly squeezed into the slot 502 under the driving action of the mating thread section, thus preventing the small nozzle 1 and the moving arc contact 2 from axially disengaging. This prevents the small nozzle 1 from moving axially due to heat, and keeps the threaded connection between the small nozzle 1 and the moving arc contact 2 in an effective pre-tight state, avoiding the small nozzle 1 from loosening and falling off, thereby ensuring the arc-extinguishing capacity of the arc-extinguishing chamber and the reliability of the circuit breaker's breaking current.

[0041] Example 2: The main difference from Example 1 is that a slot is provided on the small nozzle, and correspondingly, a hook is provided on the conductive connector 5. When the small nozzle is screwed onto the conductive connector, the hook is forcibly squeezed into the slot.

[0042] Example 3: The main difference from Example 1 is that the hook-groove mating structure is located on the rear side of the screwing direction of the threaded connection structure. At this time, the hook-groove mating structure is blocked by the small nozzle, and the screwing situation of the small nozzle cannot be seen directly.

[0043] Example 4: The main difference from Example 1 is that the slot on the conductive connector and the hook on the small nozzle are fitted with a clearance, and the hook can move slightly axially in the slot.

[0044] Example 5: The main difference from Example 1 is that the mounting base is a conductive connector. The conductive connector is provided with a matching thread section that matches the nozzle thread section on the small nozzle and a slot that matches the hook on the small nozzle. The matching slot is located on the rear side of the thread section. The small nozzle is screwed onto the conductive connector.

[0045] Example 6: The main difference from Example 1 is that the moving arc contact is fixed to the conductive connector by screws.

[0046] Example 7: The main difference from Example 1 is that both the moving main contact and the conductive connector are threadedly connected to the pressure cylinder. In other embodiments, the conductive connector and the pressure cylinder can also be an integral structure.

[0047] Example 8: The main difference from Example 1 is that the large nozzle is connected to the conductive connector by a thread.

[0048] The present invention also provides an embodiment of the nozzle connection structure of the arc-extinguishing chamber, the specific structure of which has been shown in the above embodiments of the arc-extinguishing chamber and will not be repeated here.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A nozzle connection structure for an arc-extinguishing chamber, comprising a small nozzle (1) and a mounting base, wherein the small nozzle (1) and the mounting base are connected by a threaded connection structure, characterized in that: The small nozzle (1) and the mounting base are axially anti-detached through a hook-and-groove mating structure consisting of a hook (102) on one side and a groove (502) on the other side. The hook (102) and the groove (502) are forcibly mated. When the small nozzle (1) is screwed onto the mounting base through the threaded connection structure, the hook (102) is forcibly squeezed into the groove (502) under the helical drive of the mating threaded section. The mounting base includes a conductive connection seat (5) for connecting the pull rod (3) and the moving main contact (6) and a moving arc contact (2) fixedly connected to the conductive connection seat. The threaded section of the base of the threaded connection structure on the mounting base is located on the moving arc contact (2). The hook (102) or slot (502) on the mounting base of the structure is located on the conductive connection seat (5). The moving arc contact (2) is threadedly connected to the conductive connection seat through the contact external thread section (20). The contact external thread section (20) is located in front of the screwing direction of the base thread section. The base thread section is located on the outer circumferential surface of the radially convex ring (21) provided on the moving arc contact (2). One end face of the radially convex ring is stopped and engaged with the conductive connection seat. The inner side of the small nozzle (1) is provided with an inner stop (11). The inner stop is located behind the screwing direction of the nozzle thread section (101) on the small nozzle of the threaded connection structure. The other end face of the radially convex ring (21) is stopped and engaged with the inner stop (11).

2. The arc-extinguishing chamber nozzle connection structure according to claim 1, characterized in that: The hook-groove fit structure is located on the front side of the threaded connection structure in the direction of screwing.

3. The arc-extinguishing chamber nozzle connection structure according to claim 1, characterized in that: The hook (102) is stopped and limited by the groove (502) in the axial direction of the small nozzle (1).

4. An arc-extinguishing chamber, including a moving contact assembly, characterized in that: The moving contact assembly includes a small nozzle (1) and a mounting base, which are connected by a threaded connection structure. The small nozzle (1) and the mounting base are axially anti-detached via a hook-and-groove mating structure consisting of a hook (102) on one side and a groove (502) on the other side. The hook (102) and groove (502) are forcibly mated. When the small nozzle (1) is screwed onto the mounting base via the threaded connection structure, the hook (102) is forcibly squeezed into the groove (502) under the helical drive of the mating thread section. The mounting base includes a conductive connection seat (5) for connecting the pull rod (3) and the moving main contact (6), and a moving arc contact (2) fixedly connected to the conductive connection seat. The threaded connection structure is located on the mounting base. The base thread section on the body is located on the moving arc contact (2). The hook (102) or slot (502) of the hook-slot mating structure on the mounting base is located on the conductive connection seat (5). The moving arc contact (2) is threadedly connected to the conductive connection seat through the contact external thread section (20). The contact external thread section (20) is located in front of the screwing direction of the base thread section. The base thread section is located on the outer circumferential surface of the radially convex ring (21) provided on the moving arc contact (2). One end face of the radially convex ring is stopped and mated with the conductive connection seat. An inner stop (11) is provided on the inner side of the small nozzle (1). The inner stop is located behind the screwing direction of the nozzle thread section (101) on the small nozzle of the threaded connection structure. The other end face of the radially convex ring (21) is stopped and mated with the inner stop (11).

5. The arc-extinguishing chamber according to claim 4, characterized in that: The hook-groove fit structure is located on the front side of the threaded connection structure in the direction of screwing.

6. The arc-extinguishing chamber according to claim 4, characterized in that: The hook (102) is stopped and limited by the groove (502) in the axial direction of the small nozzle (1).

7. The arc-extinguishing chamber according to claim 4, characterized in that: The arc-extinguishing chamber also includes a compressor cylinder (4) and a moving main contact (6). The outer side of the conductive connecting seat (5) included in the mounting base has a connecting flange. The moving main contact (6) is fixedly connected to the connecting flange through a threaded connector and presses the compressor cylinder (4) between the moving main contact (6) and the conductive connecting seat (5).

8. The arc-extinguishing chamber according to claim 7, characterized in that: The arc-extinguishing chamber also includes a large nozzle (7), an inner baffle (601) on the moving main contact (6), and a clamping flange (701) on the outer side of the large nozzle (7). When the moving main contact (6) is connected to the conductive connection seat (5), the clamping flange is pressed and fixed on the conductive connection seat (5) by the inner baffle.

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