A connecting structure of a moving contact rod, a flexible connection and a pull rod for a vacuum arc-extinguishing chamber

Abstract

The application relates to a connecting structure of a moving contact rod, a flexible connection and a pull rod for a vacuum arc-extinguishing chamber, and belongs to the technical field of high-voltage switch devices. The end of the moving contact rod of the arc-extinguishing chamber is provided with an outer surface provided with external threads, and the axial center line of the end extends inwardly to a central threaded hole. The flexible connection is provided with at least two hardened areas and corresponding connecting holes, one of the hardened areas is located at the central position of the flexible connection and is sleeved on the external threads of the moving contact rod of the arc-extinguishing chamber. Thread one and thread two are respectively located on outer cylindrical surfaces with different diameters and form a positioning section surface between the two, thread one is screw-connected with the central threaded hole of the moving contact rod of the arc-extinguishing chamber until the positioning section surface is tightly attached to the end surface of the moving contact rod of the arc-extinguishing chamber, a locking nut, a spring washer and a flat washer are sequentially sleeved on thread two, and the locking nut tightly presses and fixes the middle hardened area of the flexible connection on the middle connecting block by screwing. The application is favorable for solving the contradiction between high-precision assembly and high-efficiency production of special-function medium-voltage switch devices.

Description

Technical Field

[0001] This invention belongs to the technical field of high-voltage switchgear, and in particular relates to a connection structure for a moving contact rod, flexible connection and pull rod for a vacuum interrupter. Background Technology

[0002] As a core component in the field of AC high-voltage switchgear, the vacuum interrupter's moving contact and stationary contact constitute the key conductive links in the main circuit of the switchgear. To achieve a reliable electrical connection between the moving contact and the external busbar, and to ensure the moving contact's freedom of movement during closing and opening operations, existing technologies generally employ transitional components such as pull rods or flexible connections to connect the moving contact to the main circuit of the switchgear. This connection structure must effectively transmit the mechanical driving force of the operating mechanism while ensuring the smooth flow of current in the main circuit, and accommodate the reciprocating motion of the moving contact.

[0003] Currently, the mainstream connection structure of the arc-extinguishing chamber moving contact rod, flexible connector, and pull rod mainly falls into two categories. The first type is suitable for applications with relatively low rated current in the main circuit. Its technical solution involves using the external thread at the end of the pull rod to mate with the threaded hole on the end face of the arc-extinguishing chamber moving contact rod. Standard fasteners such as flat washers, spring washers, and nuts are used to directly press the hardened contact surface of the flexible connector onto the end face of the moving contact rod. Current is conducted through the contact surface between the end face of the arc-extinguishing chamber moving contact rod and the contact surface of the flexible connector. However, this structure is limited by the cross-sectional area of ​​the arc-extinguishing chamber moving contact rod end, resulting in a small effective cross-sectional area of ​​the conductive path. This limits the current-carrying capacity and makes it difficult to meet the thermal and mechanical effect requirements of high-current applications, posing a risk of overheating of the conductive contact surface and insufficient mechanical strength. The second solution addresses the application requirements of higher rated current in the main circuit. It uses an intermediate connecting copper block as a transition conductor to connect the flexible connector to the outer conical surface of the arc-extinguishing chamber moving contact rod. Specifically, the flexible connection is fastened to the intermediate connecting copper block with bolts. The inner conical hole of the intermediate connecting copper block mates with the outer conical surface of the arc-extinguishing chamber's moving contact rod, which has a certain taper. Then, the external thread at the end of the pull rod engages with the threaded hole at the end of the arc-extinguishing chamber's moving contact rod. The axial tension of the pull rod presses the intermediate connecting copper block tightly against the outer conical surface of the arc-extinguishing chamber's moving contact rod, thus ensuring that current reliably passes through the connecting conical surface between the two. While this method improves current-carrying capacity to some extent, both of these existing connection structures share a common technical defect: after assembly, it is impossible to accurately control and guarantee the axial dimension between the end face of the pull rod away from the vacuum arc-extinguishing chamber and the end of the arc-extinguishing chamber's moving contact rod.

[0004] With advancements in modern manufacturing technologies, the production and assembly precision of switchgear operating mechanisms has significantly improved. This necessitates that the arc-extinguishing chamber moving contact rod, flexible connection, and pull rod assemblies, which are matched and connected to the operating mechanism, possess precise and consistent axial dimensions. However, the axial dimensions of the connection structures in existing technologies are uncertain after assembly. Operators must spend considerable time repeatedly measuring and adjusting to meet the matching requirements of the operating mechanism, severely hindering the improvement of assembly efficiency. This makes it difficult to meet the stringent requirements of modern industrial mass production for process cycle time and product quality consistency, becoming a technical bottleneck restricting the manufacturing efficiency and reliability of medium-voltage switchgear. Summary of the Invention

[0005] The purpose of this invention is to overcome the technical shortcomings of existing vacuum interrupter moving contact rod, flexible connection, and pull rod connection structures, which suffer from insufficient current-carrying capacity and difficulty in precisely controlling the axial dimension from the pull rod to the end of the moving contact rod after assembly. This invention provides a connection structure that can meet the reliable current-carrying requirements of multi-faceted contact under high-current conditions, and achieve self-positioning of the axial dimension through hard contact between the pull rod positioning section and the end face of the moving contact rod. This structure significantly improves assembly efficiency and product consistency by simplifying component design and processes and optimizing the assembly sequence. It can adapt to both single-piece and batch production needs, effectively resolving the contradiction between high-precision assembly and high-efficiency production of special-function medium-voltage switchgear.

[0006] To achieve the above objectives, the present invention provides a connection structure for a moving contact rod, a flexible connection, and a pull rod in a vacuum interrupter, comprising a moving contact rod located at the center of the end of the vacuum interrupter, wherein the end of the moving contact rod has an external thread on its outer surface and a central threaded hole extending inward from the end axis; the moving contact rod is fitted with an intermediate connecting block and a flexible connection, the intermediate connecting block having a threaded hole that engages with the external thread, and the flexible connection having at least two hardened sections and corresponding connecting holes, wherein one of the hardened sections is located at the center of the flexible connection and is fitted into the connecting block through its connecting hole. The external thread of the moving contact rod of the arc-extinguishing chamber is provided; the moving contact rod of the arc-extinguishing chamber is connected to a pull rod through the central threaded hole. One end of the pull rod is provided with thread one and thread two. Thread one and thread two are located on outer cylindrical surfaces of different diameters and form a positioning section between them. Thread one is screwed into the central threaded hole of the moving contact rod of the arc-extinguishing chamber until the positioning section is tightly fitted with the end face of the moving contact rod of the arc-extinguishing chamber. A lock nut, a spring washer and a flat washer are sequentially fitted on thread two. The lock nut is tightened to press and fix the hardened area in the middle of the flexible connection onto the intermediate connecting block.

[0007] Preferably, the external thread at the end of the moving contact rod of the arc-extinguishing chamber is coaxial with the central threaded hole. The external thread is used to support and position the intermediate connecting block and the flexible connection. The central threaded hole forms a mating reference for direct connection with the pull rod, forming a double-threaded connection structure.

[0008] Preferably, the positioning section of the pull rod is a stepped surface perpendicular to the axis of the pull rod, the first thread is located at the end of the pull rod and is used to connect with the central threaded hole, the second thread is used to assemble the lock nut, and the stepped surface formed by the diameter difference of the two threads constitutes the positioning section.

[0009] Preferably, the tie rod is limited by hard contact between the positioning section and the end face of the moving contact rod of the arc-extinguishing chamber, thereby uniquely determining the axial position of the tie rod relative to the moving contact rod of the arc-extinguishing chamber. This ensures that the installation dimensions between the end face of the tie rod away from the vacuum arc-extinguishing chamber and the end of the moving contact rod of the arc-extinguishing chamber do not require measurement and adjustment to meet the design requirements.

[0010] Preferably, the flexible connection has three hardened regions and corresponding connection holes, one of which is located at the geometric center of the flexible connection, and the other two are symmetrically arranged on both sides. The three hardened regions are connected by a flexible unhardened strip to achieve a bending transition, forming a double-sided high current carrying capacity.

[0011] Preferably, the shape of the intermediate connecting block can be designed as square, cylindrical or irregular structure according to actual needs, and the threaded hole inside it passes through the central axis of the intermediate connecting block. The bottom surface of the intermediate connecting block is used to form a stable surface contact conduction path with the flexible connection.

[0012] Preferably, a multi-path large-area contact current flow path is formed: the current is conducted from the moving contact rod of the arc extinguishing chamber through the multi-turn thread engagement surface between the external thread and the internal thread hole of the intermediate connecting block to the intermediate connecting block, then through the planar contact between the bottom surface of the intermediate connecting block and the top surface of the hardened area in the middle of the flexible connection to the flexible connection, and finally through the hardened areas on both sides of the flexible connection to the external connecting copper busbar.

[0013] Preferably, the intermediate connecting block is connected to the moving contact rod of the arc-extinguishing chamber via multiple turns of thread, and the locking nut is tightened to press the flexible connection onto the intermediate connecting block, forming a double fastening structure to ensure that the connection does not loosen under mechanical vibration and electrothermal cycle conditions.

[0014] Preferably, during assembly, the intermediate connecting block is first screwed into the external thread of the arc-extinguishing chamber moving contact rod to a suitable position. Then, the flexible connector is fitted onto the arc-extinguishing chamber moving contact rod so that the hardened area in the middle contacts the intermediate connecting block. Next, the pull rod, pre-installed with the locking nut, the spring washer, and the flat washer, is screwed into the central threaded hole through the thread until the positioning section fits against the end face. Finally, the locking nut is tightened to secure the flexible connector. The entire assembly process does not require additional measurement or adjustment of the axial dimensions.

[0015] Preferably, the connection between the intermediate connecting block and the flexible connection is achieved through a large surface contact. The current flows from the moving contact rod of the arc-extinguishing chamber to the intermediate connecting block through multiple turns of fastening threads, and then flows from the intermediate connecting block to the flexible connection through a large flat surface contact. Structurally, this ensures multi-faceted or large-faceted contact on the current flow path of the entire component, thus ensuring the high current carrying capacity of the connection structure.

[0016] In summary, the present invention has the following beneficial technical effects:

[0017] The connection structure of this invention has significant advantages in design and manufacturing. The components are simple in structure and the machining process is simplified, allowing for completion through conventional CNC turning, milling, and heat treatment, ensuring high machining accuracy. Key mating parts such as the external thread and central threaded hole of the arc-extinguishing chamber's moving contact rod, the double-threaded section and positioning section of the pull rod, and the threaded hole of the intermediate connecting block can all be machined in a single setup, ensuring that dimensional and positional tolerances such as coaxiality, perpendicularity, and flatness meet design requirements. Simultaneously, the hardened area of ​​the flexible connection is achieved through localized heat treatment. Standard fasteners such as flat washers, spring washers, and locking nuts can be selected to reduce manufacturing costs, or non-standard parts can be customized according to special working conditions, flexibly adapting to different needs. This structure not only has fewer parts and a shorter process chain but also is compatible with both single-piece prototyping and mass production, effectively shortening the production cycle, reducing manufacturing costs, and significantly improving manufacturability and economy.

[0018] This connection structure achieves a breakthrough improvement in assembly efficiency and dimensional accuracy control. The entire assembly process only requires screwing each part in and tightening it in place sequentially, eliminating the need for repeated measurements and adjustments using measuring tools such as calipers. Through the hard-contact limiting design between the tie rod positioning section and the end face of the arc-extinguishing chamber's moving contact rod, the axial position of the tie rod relative to the moving contact rod is uniquely determined, thus precisely ensuring the installation dimensions between the distal end of the tie rod and the end of the arc-extinguishing chamber's moving contact rod, completely solving the problem of inaccurate dimensional control in existing technologies. This assembly method with built-in positioning significantly simplifies the operation process, making assembly simple and quick, significantly reducing assembly time, avoiding dimensional deviations caused by human measurement errors, and greatly improving assembly efficiency and product qualification rate. It is particularly suitable for the stringent requirements of modern industrial mass production for process cycle time and product quality consistency, effectively improving productivity.

[0019] This invention exhibits excellent electrical performance and connection reliability. Through the synergistic action of the intermediate connecting block, locking nut, and pull rod, a reliable large-area connection is achieved between the flexible connector and the moving contact rod of the arc-extinguishing chamber. After the current flows out from the moving contact rod of the arc-extinguishing chamber, it sequentially passes through the multi-turn meshing contact surface between the external thread and the internal thread hole of the intermediate connecting block, the planar contact surface between the bottom surface of the intermediate connecting block and the hardened area in the middle of the flexible connector, and then branches along the hardened areas on both sides of the flexible connector to the main busbar. The entire current path adopts a multi-faceted and large-area contact design, which effectively reduces contact resistance and significantly improves the short-time withstand current and peak withstand current capabilities, fully meeting the force and thermal effect requirements under high current conditions. Meanwhile, the continuous anti-loosening preload provided by the spring washer ensures that the connection remains secure and reliable under mechanical vibration and electrothermal cycling conditions. The hard contact between the pull rod and the end face of the moving contact rod also provides rigid support for the assembly, avoiding axial movement and improving the stability and repeatability of the switching equipment's opening and closing actions. This comprehensively overcomes the dual defects of insufficient current carrying capacity and uncontrollable axial dimensions in the existing technology, providing a highly reliable connection solution for special function medium-voltage switchgear. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the connection structure of the moving contact rod, flexible connection and pull rod for a vacuum interrupter according to the present invention;

[0021] Figure 2 This is a schematic diagram of the vacuum interrupter and the moving contact rod of the interrupter in the connection structure of the moving contact rod, flexible connection and pull rod for the vacuum interrupter of the present invention;

[0022] Figure 3 This is a schematic diagram of the intermediate connecting block in the connection structure of the moving contact rod, flexible connection and pull rod for a vacuum interrupter according to the present invention;

[0023] Figure 4 This is a schematic diagram of the flexible connection in the connection structure of the moving contact rod, flexible connection and pull rod for a vacuum interrupter according to the present invention;

[0024] Figure 5 This is a schematic diagram of the connection structure of the moving contact rod, flexible connection and pull rod for a vacuum interrupter according to the present invention.

[0025] Reference numerals: 1. Vacuum interrupter; 2. Moving contact rod of the interrupter; 3. Intermediate connecting block; 4. Flexible connection; 5. Flat washer; 6. Spring washer; 7. Locking nut; 8. Pull rod; 9. External thread; 10. End face; 11. Center threaded hole; 12. Threaded hole; 13. Hardened area; 14. Thread one; 15. Positioning section; 16. Thread two. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] This invention discloses a connection structure for a moving contact rod, flexible connection, and pull rod in a vacuum interrupter. This structure addresses the technical shortcomings of existing mainstream connection methods for the moving contact rod 2, flexible connection 4, and pull rod 8 in interrupters, namely insufficient current carrying capacity and difficulty in precisely controlling assembly dimensions. It proposes an innovative solution to ensure that the connection structure meets the requirements for high current carrying capacity while achieving precise control of the axial dimension between the distal end of the pull rod 8 and the end of the moving contact rod 2 in the interrupter. Furthermore, the structure of each component has excellent manufacturability, suitable for both single-piece customization and mass production. The core components of the connection structure of this invention include a vacuum interrupter 1, an interrupter moving contact rod 2, an intermediate connecting block 3, a flexible connection 4, a flat washer 5, a spring washer 6, a locking nut 7, and a pull rod 8. These components are organically integrated through specific threaded mating and surface contact methods.

[0028] The moving contact rod 2 of the arc-extinguishing chamber is located at the bottom center of the vacuum arc-extinguishing chamber 1. As the moving terminal for current transmission, it has two connection structures at the end away from the vacuum arc-extinguishing chamber 1: an external thread 9 and a central threaded hole 11. The external thread 9 is distributed on the outer circumferential surface of the end of the moving contact rod and is used to support the fitting and positioning of the intermediate connecting block 3 and the flexible connection 4. The central threaded hole 11 extends inward along the axis of the moving contact rod and forms a mating reference for direct connection with the pull rod 8. This double-threaded structure design provides a basis for subsequent multi-layer assembly.

[0029] As a key transition component for current transmission, the intermediate connecting block 3 has an internal threaded hole 12 that matches the external thread 9 of the moving contact rod 2 of the arc extinguishing chamber. The threaded hole 12 passes through the central axis of the intermediate connecting block 3, so that the intermediate connecting block 3 can be screwed onto the external thread 9 of the moving contact rod. The shape can be designed as square, cylindrical or other irregular structure according to the actual electrical performance and spatial layout requirements. The bottom surface of the intermediate connecting block 3 has a high flatness requirement, which is used to form a stable surface contact conduction path with the flexible connection 4.

[0030] The flexible connector 4 has three hardened areas and corresponding connection holes. One hardened area 13 is located at the geometric center of the flexible connector 4, and the other two hardened areas 13 are symmetrically arranged on both sides. The three hardened areas 13 are connected by a flexible unhardened strip for bending transition. This design enables the flexible connector 4 to have a high current carrying capacity on both sides, and the current can be split from the middle to both sides. If the application scenario only requires single-sided conductivity, the flexible connector 4 can be simplified to a structure with two hardened areas 13 and corresponding connection holes, and current conduction can be achieved by connecting the hardened area 13 on one side to an external copper busbar. The flexible connector 4 can be formed by stacking multiple layers of thin copper strips or aluminum strips and then using a heat treatment hardening process.

[0031] The flat washer 5, spring washer 6, and locking nut 7 used for fastening can be standard fasteners to reduce costs, or non-standard parts can be designed for special working conditions to meet specific pressure or anti-loosening requirements. The tie rod 8, as the core component driving the movement of the arc-extinguishing chamber's moving contact rod 2, has two different threaded sections at one end: thread one 14 and thread two 16. These two threads are machined on outer cylindrical surfaces of different diameters, with a precision-machined positioning section 15 providing a transition. This positioning section 15 is perpendicular to the axis of the tie rod 8 and requires a high surface roughness. Thread one 14 is located at the end of the tie rod 8 and is used to engage with the central threaded hole 11 of the arc-extinguishing chamber's moving contact rod 2. Thread two 16 is used to assemble the locking nut 7, spring washer 6, and flat washer 5. The stepped surface formed by the difference in diameter between the two threads is the positioning section 15. The connecting positioning section 15 on the tie rod 8 fits against the end face 10 of the arc-extinguishing chamber's moving contact rod 2 to ensure accurate dimensions from the end of the arc-extinguishing chamber's moving contact rod 2 to the other end of the tie rod 8 after assembly.

[0032] During assembly, the intermediate connecting block 3 is first screwed into the external thread 9 of the arc-extinguishing chamber moving contact rod 2 through its threaded hole 12. The axial position is adjusted according to the thickness of the flexible connection 4 and the designed preload. Then, the flexible connection 4 is fitted onto the external thread 9 of the arc-extinguishing chamber moving contact rod 2 through its central connecting hole, so that the bottom surface of the hardened area 13 in the middle of the flexible connection 4 initially contacts the surface of the intermediate connecting block 3. Simultaneously, a locking nut 7 is pre-installed on the thread 16 of the pull rod 8 and screwed to near the root of the thread 16. Then, the spring washer 6 and the flat washer 5 are sequentially fitted onto the pull rod 8, with the tapered opening of the spring washer 6 facing the flat washer 5 and the flat surface of the flat washer 5 facing the flexible connection 4. Finally, the thread 14 at the end of the pull rod 8 is aligned with the central threaded hole 1 of the arc-extinguishing chamber moving contact rod 2. 1. Tighten the rod until the positioning section 15 on the pull rod 8 and the end face 10 of the moving contact rod 2 of the arc-extinguishing chamber are in close contact. At this time, the axial position of the pull rod 8 relative to the moving contact rod is uniquely determined, thus accurately ensuring the installation dimensions between the other end face 10 of the pull rod 8 away from the vacuum arc-extinguishing chamber 1 and the end of the moving contact rod 2 of the arc-extinguishing chamber, without the need for repeated measurement and adjustment using measuring tools such as vernier calipers. Finally, tighten the locking nut 7 with a special wrench, so that the locking nut 7 pushes the flat washer 5 and the spring washer 6 to move axially along the pull rod 8, firmly pressing the hardened area 13 in the middle of the flexible connection 4 onto the bottom surface of the intermediate connecting block 3. The elastic deformation of the spring washer 6 provides a continuous anti-loosening pre-tightening force to ensure that the connection does not loosen under mechanical vibration and electrothermal cycle conditions. This completes the assembly of the entire connection structure.

[0033] The current flow path design of the connection structure of this invention fully embodies the principles of multi-faceted and large-area contact. After the current flows out from the moving contact rod of the vacuum interrupter 1, it is first conducted through the spiral contact surface formed by the multi-turn threaded engagement between the external thread 9 of the moving contact rod and the threaded hole 12 of the intermediate connecting block 3. The meshing of the multi-turn thread significantly increases the effective conductive area and reduces the contact resistance. Then, the current enters the body of the intermediate connecting block 3 and is conducted a second time through the planar contact between the bottom surface of the intermediate connecting block 3 and the top surface of the hardened area 13 in the middle of the flexible connection 4. This contact surface is precision machined and pressed together by fastening force, resulting in extremely low contact resistance. The current is diverted along the multi-layer metal strip inside the flexible connection 4 to the hardened areas 13 on both sides, and finally connected to the external main busbar or branch copper busbar through the connection hole on the hardened area 13, completing the entire current transmission link.

[0034] Because the threaded engagement, flat pressing, and flexible connection 4-shunting components all employ a large contact surface design, the entire connection structure possesses excellent short-time withstand current and peak withstand current capabilities, fully meeting the force and thermal effect requirements of high-current switching equipment. Furthermore, the hard contact design between the positioning section 15 of the pull rod 8 and the end face 10 of the arc-extinguishing chamber moving contact rod 2 not only achieves precise control of the axial dimensions but also provides reliable rigid support for the entire assembly, preventing axial movement caused by thread clearance and improving the stability and repeatability of the switching equipment's opening and closing operations.

[0035] The manufacturing process of each component in the connection structure of this invention is simple. The external thread 9 and the central threaded hole 11 of the arc-extinguishing chamber moving contact rod 2 can be machined in one clamping on a CNC lathe, ensuring coaxiality and perpendicularity to the end face 10. The threaded hole 12 and the bottom surface of the intermediate connecting block 3 can be machined by turning or milling, and the precision is easy to control. The hardened area 13 of the flexible connection 4 can be achieved through local heat treatment, and the connecting hole is formed by stamping or drilling. The two threads of the pull rod 8 and the positioning section 15 are machined by turning, and the dimensional accuracy can reach IT7 level or above. During the assembly process, it is only necessary to screw each part in and tighten it in place in sequence, without the need for additional shims or auxiliary processes such as applying conductive paste, which greatly simplifies the assembly process and improves production efficiency. It is particularly suitable for special function medium-voltage switchgear with strict requirements for assembly accuracy and current carrying capacity, such as solid-insulated switchgear and environmentally friendly gas-insulated switchgear, and has significant engineering application value and economic benefits.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A connection structure for a moving contact rod, a flexible connection, and a pull rod in a vacuum interrupter, characterized in that, The device includes a movable contact rod (2) of the arc-extinguishing chamber located at the center of the end of the vacuum arc-extinguishing chamber (1). The movable contact rod (2) has an external thread (9) on its outer surface at the end, and a central threaded hole (11) extending inward from the centerline of the end. The movable contact rod (2) is fitted with an intermediate connecting block (3) and a flexible connection (4). The intermediate connecting block (3) has a threaded hole (12) that engages with the external thread (9). The flexible connection (4) has at least two hardened areas (13) and corresponding connecting holes. One of the hardened areas (13) is located at the center of the flexible connection (4) and is fitted onto the external thread (9) of the movable contact rod (2) through its connecting hole. The movable contact rod (2) passes through the central threaded hole (11) 11) A pull rod (8) is connected. One end of the pull rod (8) is provided with thread one (14) and thread two (16). Thread one (14) and thread two (16) are located on outer cylindrical surfaces of different diameters and form a positioning section (15) between them. Thread one (14) is screwed into the central threaded hole (11) of the arc-extinguishing chamber moving contact rod (2) until the positioning section (15) is tightly fitted with the end face (10) of the arc-extinguishing chamber moving contact rod (2). Locking nut (7), spring washer (6) and flat washer (5) are sequentially fitted on thread two (16). Locking nut (7) presses and fixes the hardened area (13) in the middle of the soft connection (4) onto the intermediate connecting block (3) by tightening.

2. The connection structure of the moving contact rod, flexible connection, and pull rod for a vacuum interrupter according to claim 1, characterized in that, The external thread (9) at the end of the moving contact rod (2) of the arc extinguishing chamber is coaxial with the central threaded hole (11). The external thread (9) is used to support the fitting and positioning of the intermediate connecting block (3) and the soft connection (4). The central threaded hole (11) forms a mating reference for direct connection with the pull rod (8), forming a double threaded connection structure.

3. The connection structure of the moving contact rod, flexible connection, and pull rod for a vacuum interrupter according to claim 2, characterized in that, The positioning section (15) of the pull rod (8) is a stepped surface perpendicular to the axis of the pull rod (8). The first thread (14) is located at the end of the pull rod (8) and is used to connect with the central threaded hole (11). The second thread (16) is used to assemble the locking nut (7). The stepped surface formed by the difference in diameter of the two threads constitutes the positioning section (15).

4. The connection structure of the moving contact rod, flexible connection, and pull rod for a vacuum interrupter according to claim 3, characterized in that, The pull rod (8) is limited by hard contact between the positioning section (15) and the end face (10) of the arc-extinguishing chamber moving contact rod (2), thereby achieving a unique determination of the axial position of the pull rod (8) relative to the arc-extinguishing chamber moving contact rod (2). This ensures that the installation dimensions between the end face (10) of the pull rod (8) away from the vacuum arc-extinguishing chamber (1) and the end of the arc-extinguishing chamber moving contact rod (2) do not need to be measured or adjusted to meet the design requirements.

5. The connection structure of the moving contact rod, flexible connection, and pull rod for a vacuum interrupter according to claim 4, characterized in that, The flexible connection (4) is provided with three hardened areas (13) and corresponding connection holes. One hardened area (13) is located at the geometric center of the flexible connection (4), and the other two hardened areas (13) are symmetrically arranged on both sides. The three hardened areas (13) are connected by a flexible unhardened strip to achieve a bending transition, forming a double-sided high current carrying capacity.

6. The connection structure of the moving contact rod, flexible connection, and pull rod for a vacuum interrupter according to claim 5, characterized in that, The shape of the intermediate connecting block (3) can be designed as square, cylindrical or irregular structure according to actual needs. The threaded hole (12) inside it passes through the central axis of the intermediate connecting block (3). The bottom surface of the intermediate connecting block (3) is used to form a stable surface contact conduction path with the soft connection (4).

7. The connection structure of the moving contact rod, flexible connection, and pull rod for a vacuum interrupter according to claim 6, characterized in that, A multi-path large-area contact current flow path is formed: the current is conducted from the moving contact rod (2) of the arc extinguishing chamber through the multi-turn thread meshing surface between the external thread (9) and the internal thread hole (12) of the intermediate connecting block (3) to the intermediate connecting block (3), then through the planar contact between the bottom surface of the intermediate connecting block (3) and the top surface of the hardened area (13) in the middle of the flexible connection (4) to the flexible connection (4), and finally through the hardened areas (13) on both sides of the flexible connection (4) to the external connecting copper busbar.

8. The connection structure of the moving contact rod, flexible connection, and pull rod for a vacuum interrupter according to claim 7, characterized in that, The intermediate connecting block (3) is connected to the moving contact rod (2) of the arc-extinguishing chamber by multiple turns of thread. The locking nut (7) presses the soft connection (4) onto the intermediate connecting block (3) by tightening, forming a double fastening structure to ensure that the connection does not loosen under mechanical vibration and electrothermal cycle conditions.

9. The connection structure of the moving contact rod, flexible connection, and pull rod for a vacuum interrupter according to claim 8, characterized in that, During assembly, first screw the intermediate connecting block (3) into the external thread (9) of the arc-extinguishing chamber moving contact rod (2) to a suitable position, then put the flexible connection (4) on the arc-extinguishing chamber moving contact rod (2) so that the hardened area (13) in the middle contacts the intermediate connecting block (3), then screw the pull rod (8) pre-installed with the locking nut (7), the spring washer (6) and the flat washer (5) into the center threaded hole (11) through the thread one (14) until the positioning section (15) fits with the end face (10), and finally tighten the locking nut (7) to secure the flexible connection (4). The entire assembly process does not require additional measurement and adjustment of the axial dimension.

10. The connection structure of the moving contact rod, flexible connection, and pull rod for a vacuum interrupter according to claim 9, characterized in that, The connection between the intermediate connecting block (3) and the flexible connection (4) is achieved through a large surface contact. The current flows from the moving contact rod (2) of the arc-extinguishing chamber to the intermediate connecting block (3) through multiple turns of fastening thread, and then flows from the intermediate connecting block (3) to the flexible connection (4) through a large plane contact. Structurally, this ensures multi-faceted or large-faceted contact on the current flow path of the entire component, ensuring the large current flow capacity of the connection structure.

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