Vacuum butterfly valve

Abstract

The invention discloses a vacuum butterfly valve which aims at solving the problems that a traditional butterfly valve generates more particles and is poor in reliability and free of mechanical self-locking. The vacuum butterfly valve comprises an air cylinder assembly, a valve element assembly and a valve body. A first rail, a second rail and a third rail which are different in geometrical shape are machined on the surface of the piston. A special-shaped screw fixed to the cylinder barrel is matched with a first track and a second track on the outer surface of the piston, so that the piston is restrained to generate linear and rotating compound motion. A roller at the head end of the connecting rod is matched with a third rail on the inner surface of the piston, so that composite motion of the piston is converted into specific motion of the connecting rod. The connecting rod drives the valve element to sequentially execute the composite action of separating from the valve seat, rotating by 90 degrees to be opened / closed and then pressing the valve seat. In the full-open / full-closed position of the valve, the specific geometrical shape of the third rail enables the acting force direction to be perpendicular to the piston movement direction, and gas-cut mechanical self-locking is achieved.

Description

Technical Field

[0001] This invention relates to a valve, and more particularly to a vacuum butterfly valve. Background Technology

[0002] Vacuum valves are key components in vacuum systems used to change the direction of airflow, regulate flow, or cut off / connect pipelines. In high-precision fields such as thin-film deposition, mass spectrometry, and gas analysis, extremely high requirements are placed on vacuum valves: First, valve operation should generate only a very small amount of gaseous particles to avoid contaminating the vacuum chamber and the process; second, valves must possess high reliability and be able to withstand dust and other contaminants that may be present in the process environment; finally, valves should have a mechanical locking function similar to a gate valve to ensure that the valve state does not change in the event of an unexpected failure of the driving gas source, thus ensuring system and process safety.

[0003] Currently widely used traditional pneumatic butterfly valves typically consist of a pneumatic actuator, valve stem, valve body, and valve core, with the valve stem connected to the valve body via a bearing. This structure has inherent limitations and cannot meet the requirements of the aforementioned high-end operating conditions: The low-particle requirement cannot be met: the bearing between the valve stem and the valve body will experience metal-to-metal friction during operation, inevitably producing metal particles that pollute the vacuum environment.

[0004] Reliability risks exist: In environments with high levels of dust and process contaminants, the bearing connection between the valve stem and valve body is prone to jamming or even seizing due to contaminant intrusion, leading to valve failure.

[0005] Lack of safety assurance: Traditional pneumatic butterfly valves typically lack mechanical locking functionality, and their valve core retention relies entirely on continuous air supply pressure. Once the air supply pressure is lost, the valve core may undergo unexpected actions due to the pressure difference in the pipeline, posing a safety hazard. Summary of the Invention

[0006] The purpose of this invention is to provide a vacuum butterfly valve to solve the technical problem that existing pneumatic butterfly valves cannot simultaneously meet the requirements of low particle generation, high operational reliability, and mechanical self-locking safety in the event of gas cut-off in high vacuum applications.

[0007] This invention is achieved using the following technical solution: a vacuum butterfly valve, comprising a cylinder assembly, a valve core assembly, and a valve body. The valve core of the valve core assembly is disposed within the valve body. The cylinder assembly includes a cylinder barrel, a piston, a connecting rod, and a drive conversion mechanism. The piston is movably disposed within the cylinder barrel, and its inner and outer surfaces are provided with multiple tracks constructed with different geometric shapes. The drive conversion mechanism includes a fixing member fixed to the cylinder barrel and a driven member connected to the connecting rod. The fixing member cooperates with at least one track on the outer surface of the piston to constrain the piston to generate an output motion that combines linear motion along its axis and rotational motion around its axis under drive. The driven member cooperates with at least another track on the inner surface of the piston to convert the combined output motion of the piston into the motion of the connecting rod. One end of the connecting rod is connected to the driven member, and the other end drives and connects to the valve core to drive the valve core to perform a combined action of disengaging from or pressing against the valve seat and rotating.

[0008] Furthermore, the piston surface has multiple tracks, including a first track and a second track on its outer cylindrical surface, and a third track on its inner cylindrical surface; the fixing member is a special-shaped screw that passes through the cylinder and mates with the first track and the second track; the driven member is a roller located at the head end of the connecting rod, and the roller is embedded in the third track.

[0009] Furthermore, the third track, along the movement path from fully closed to fully open of the valve, sequentially includes a first straight segment parallel to the piston axis, an arc segment at an angle to the piston axis, a second straight segment parallel to the piston axis, and a third straight segment parallel to the piston axis.

[0010] Furthermore, the starting point of the first straight segment and the ending point of the third straight segment of the third track, and the tangent direction of the third track are parallel to the axis of the piston, so that the valve can achieve mechanical self-locking in the fully closed and fully open positions.

[0011] Furthermore, during the valve opening process, the first and second tracks sequentially include a first straight segment that guides the piston to make a pure linear motion, a spiral segment that guides the piston to rotate around its own axis by a predetermined angle while continuing to make a linear motion, and a second straight segment that guides the piston to make a pure linear motion again.

[0012] Furthermore, the helical segment is a quarter helix, used to guide the piston to rotate 90°.

[0013] Furthermore, it also includes a base and a double-rotating block. The base is connected to the cylinder and is provided with a bearing. The double-rotating block is connected to the middle of the connecting rod by a pin and installed in the bearing, so that the connecting rod can rotate around the bearing and can rotate around the pin.

[0014] Furthermore, the valve core assembly also includes a support ring fitted onto the valve core. The support ring is made of a high-molecular wear-resistant material and is used to support and guide the valve core within the valve body.

[0015] Furthermore, each of the two ends of the connecting rod is provided with a roller, and both rollers are embedded in the third track.

[0016] A control method for a vacuum butterfly valve, characterized in that the valve opening process of the vacuum butterfly valve sequentially includes the following four stages: In the first stage, the driving piston moves in a pure linear motion along its own axis, that is, the third axis. At this time, the connecting rod and valve core remain stationary, and the valve is in a closed and self-locking state. In the second stage, the driving piston continues to move in a pure linear motion along the third axis. In this stage, the connecting rod rotates around the second axis, causing the valve core to translate and causing the sealing ring on it to disengage from the valve seat of the valve body. In the third stage, while the driving piston moves linearly along the third axis, it rotates around the third axis by a predetermined angle. In this stage, the connecting rod rotates around the first axis, thereby driving the valve core to rotate in the valve body and opening the valve. In the fourth stage, the drive piston moves in a pure linear motion along the third axis again until it reaches the end of its stroke. At this time, the connecting rod and valve core remain stationary, and the valve is in an open and self-locking state. The closing process of the vacuum butterfly valve is the exact reverse of the opening process, and consists of the following four stages: In the first stage, the driving piston starts from the end position of the valve opening and moves downward in a pure straight line along its own axis, that is, the third axis. At this time, the connecting rod and the valve core remain stationary. In the second stage, while the driving piston continues to move linearly downward along the third axis, it rotates in the opposite direction around the third axis by the predetermined angle. In this stage, the connecting rod rotates in the opposite direction around the first axis, thereby driving the valve core to rotate in the opposite direction by 90° within the valve body to achieve closure. In the third stage, the driving piston continues to move downward in a pure straight line along the third axis. In this stage, the connecting rod rotates in the opposite direction around the second axis, causing the valve core to translate and press the sealing ring on it against the valve seat of the valve body. In the fourth stage, the drive piston continues to move downward in a pure straight line to the initial position, at which point the valve returns to the closed and self-locking state.

[0017] The vacuum butterfly valve described in this invention has the following advantages: The core motion conversion mechanism of this invention is entirely sealed inside the cylinder assembly, isolating any abrasive debris that might be generated by its moving parts and preventing it from entering the vacuum flow channel. Simultaneously, the movement of the valve core assembly within the valve body is guided and supported only by a support ring made of polymer material, completely eliminating direct contact and friction between the valve core and the metal valve body. This design fundamentally eliminates the source of metal particle contamination, meeting the extremely high cleanliness requirements of vacuum processes in semiconductors, analytical instruments, and other industries.

[0018] Because the core moving parts of the valve are all sealed and protected, dust and particulate contaminants from the external environment cannot penetrate its movement path and precision mating surfaces, effectively avoiding the risk of jamming due to contamination. The valve core does not have the bearing support required by traditional butterfly valves, resulting in a simpler structure and fewer potential failure points.

[0019] Through a specific geometric design of the third track on the piston, when the valve reaches the fully closed and fully open positions, the force transmitted from the connecting rod to the roller is perpendicular to the piston's movement direction. At this point, regardless of whether the pressure from the pipeline medium attempts to push the valve open or close, it cannot be decomposed into a component force driving the piston's movement, thus achieving stable and reliable bidirectional mechanical self-locking. This function does not rely on an external air or electrical source and can absolutely guarantee the valve's state remains unchanged in the event of an unexpected failure of the drive source, greatly enhancing the system's inherent safety.

[0020] The valve's operation is broken down into a compound motion: first, vertical disengagement from the valve seat; then, rotation to open / close; and finally, vertical compression against the valve seat. This motion avoids the scraping wear between the sealing ring and the valve seat that occurs during the rotational opening and closing of traditional butterfly valves, effectively extending the service life of the sealing ring and further reducing the risk of particulate matter generated by friction.

[0021] This design decomposes complex composite motions onto different tracks, reducing the machining difficulty of individual tracks and improving the accuracy and reliability of motion control. At the same time, the inner and outer tracks have clear division of labor, forming two sets of kinematic pairs that can be independently optimized, effectively dispersing the force, reducing stress concentration and local wear, thereby extending the service life of the valve and reducing the failure rate. In addition, this structure also facilitates later maintenance and debugging. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall structure of a vacuum butterfly valve; Figure 2 This is a schematic diagram of the cylinder assembly; Figure 3 This is a schematic diagram of the track path; Figure 4 This is a schematic diagram of the valve core assembly; Figure 5 This is a schematic diagram of the overall cross-section; Figure 6 A schematic diagram of the connecting rod installation structure; In the diagram, 1-cylinder assembly, 2-valve core assembly, 3-valve body, 101-cylinder head, 102-cylinder barrel, 103-special-shaped screw, 104-piston, 105-roller, 106-pin, 107-connecting rod, 108-sealing ring, 109-double rotating block, 110-base, 111-bearing limit block, 201-valve core, 202-support ring, 203-sealing ring, 301-first axis, 302-second axis, 303-third axis, 401-first track, 402-second track, 403-third track, 501-first position point, 502-second position point, 503-third position point, 504-fourth position point, 505-fifth position point. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0026] like Figure 1-6 As shown, a vacuum butterfly valve mainly consists of a cylinder assembly 1, a valve core assembly 2, and a valve body 3.

[0027] The cylinder assembly 1 includes a cylinder head 101, a cylinder barrel 102, shaped screws 103, a piston 104, a roller 105, a pin 106, a connecting rod 107, a sealing ring 108, a double-swivel block 109, a base 110, and a bearing limiting block 111. The cylinder head 101 and the cylinder barrel 102 are connected to form the cylinder shell. The piston 104 is assembled inside the cylinder barrel 102, and its outer cylindrical surface is machined with two identical first tracks 401 and second tracks 402, and its inner cylindrical surface is machined with a third track 403. Two shaped screws 103 pass through the wall of the cylinder barrel 102 and extend into the first tracks 401 and second tracks 402 respectively. Through their cooperation with the tracks, they constrain and guide the movement of the piston 104. The base 110 is fixed to the end of the cylinder barrel 102 by screws, and a bearing is fixedly installed inside it by the bearing limiting block 111 and screws. The central axis of the bearing is defined as the first axis 301.

[0028] The double-rotating block 109 is fixedly connected to the middle of the connecting rod 107 by a pin, the central axis of which is defined as the second axis 302. The inner ring of the bearing mates with the double-rotating block 109 and is axially limited by an elastic retaining ring, allowing the connecting rod 107 and the double-rotating block 109 as a whole to rotate around the first axis 301. Simultaneously, the connecting rod 107 can also rotate relative to the double-rotating block 109 around the pin passing through it (i.e., the second axis 302). A sealing retaining ring 108 is installed on the connecting rod 107 to achieve a dynamic seal. The piston 104 has a roller 105 mounted on each side of the first end (the end closest to the piston 104) of the connecting rod 107 via a pin 106. The rollers are fixed by retaining rings and washers. Both rollers 105 are embedded in the third track 403 on the inner surface of the piston 104 and can roll within it. This restricts the axial movement of the connecting rod 107 relative to the piston 104 to a direction specified by the third track 403, and prevents it from rotating relative to the piston 104 around the third axis 303. The tail end of the connecting rod 107 is fixedly connected to the valve core assembly 2 by screws.

[0029] The valve core assembly 2 mainly includes a valve core 201, a support ring 202, and a sealing ring 203. The valve core 201 has a disc-shaped structure, and the sealing ring 203 is circumferentially mounted on it to achieve a seal when closed by fitting against the sealing surface of the valve body 3. The support ring 202 is fitted onto the valve core 201 and located inside the sealing ring 203. It is made of high-molecular wear-resistant materials such as PEEK or POM and serves as a guide and support for the movement of the valve core 201 within the valve body 3, preventing direct contact between metal parts.

[0030] The valve body 3 is a vacuum pipeline connection component, and has a sealing valve seat inside that matches the valve core 201 and the sealing ring 203. The base 110 of the cylinder assembly 1 is connected and fixed to the valve body 3 by a flange and screws.

[0031] The working principle of the vacuum butterfly valve of this invention, especially the valve opening process, can be divided into four consecutive stages based on the geometry of the third track 403 on the piston 104, namely, the first position point 501, the second position point 502, the third position point 503, the fourth position point 504, and the fifth position point 505. Assuming the initial state is that the valve is fully closed, the piston 104 is located at the bottom of the cylinder 102, and the roller 105 is located at the top of the third track 403 (i.e., the first position point 501).

[0032] First stage (from first position point 501 to second position point 502): Driving gas is introduced into the cylinder, and the piston 104 begins to move upward in a pure linear motion. During this stage, the corresponding segments of the first track 401, second track 402, and third track 403 are all straight lines parallel to the third axis 303. The roller 105 rolls within this straight segment of the third track 403, while the connecting rod 107 and the valve core assembly 2 remain stationary. This stage is the preparation stage, and the valve is still in the closed, self-locking state.

[0033] Second stage (from second position point 502 to third position point 503): Piston 104 continues to move upward in a straight line. At this time, the first track 401 and the second track 402 are still straight segments, but the third track 403 is an arc segment. Under the action of the arc segment track, the roller 105 generates lateral displacement, forcing the connecting rod 107 to rotate around the second axis 302, thereby driving the valve core 201 to move slightly, causing the sealing ring 203 on it to disengage from the sealing seat of the valve body 3.

[0034] The third stage (from the third position point 503 to the fourth position point 504): While continuing its upward linear motion, the piston 104 begins to rotate 90° counterclockwise around the third axis 303. This motion is achieved by the corresponding arc segments of the first track 401 and the second track 402 engaging with the shaped screw 103. In this segment, the first track 401 and the second track 402 form a quarter-helix wrapped around the outside of the piston 104. During this process, the corresponding segment of the third track 403 is a straight line. The 90° rotation of the piston 104, through the engagement of the roller 105 and the third track 403, is converted into a 90° rotation of the connecting rod 107 around the first axis 301, ultimately driving the valve core 201 to rotate 90° within the valve body 3, thus achieving full opening of the valve's flow section.

[0035] Fourth stage (from fourth position point 504 to fifth position point 505): Piston 104 resumes a purely linear upward movement until it reaches the end of its stroke. At this time, the corresponding segments of the first track 401, the second track 402, and the third track 403 again become straight lines parallel to the third axis 303. Connecting rod 107 and valve core assembly 2 remain stationary, and the valve is in the fully open position.

[0036] The valve closing process is the exact reverse of the valve opening process described above. That is, the piston 104 moves from the fifth position point 505 to the first position point 501, passing through the fourth, third, and second stages in sequence, and finally causes the valve core 201 to rotate 90° and fall back to press the sealing ring 203, thereby closing the valve.

[0037] The low-particle characteristics of this invention are achieved in the following way: throughout the entire movement path of the valve core assembly 2, there is no contact between the valve core 201 and the connecting rod 107 and the metal valve body 3. The valve core 201 only makes sliding contact with the valve body 3 through the support ring 202 made of polymer material, effectively eliminating metal-to-metal friction. At the same time, all moving parts inside the cylinder assembly 1, such as between the piston 104 and the cylinder 102, between the shaped screw 103 and the track, and between the roller 105 and the third track 403, are sealed inside the cylinder, and any trace amounts of wear debris that may be generated will not enter the vacuum flow channel. Therefore, the entire valve operation introduces almost no metal particulate contaminants into the vacuum system.

[0038] The mechanical self-locking characteristic of this invention is achieved in the following way: when the valve is fully closed (roller 105 is at the first position point 501) and fully open (roller 105 is at the fifth position point 505), the tangent direction of the third track 403 is parallel to the axis of the piston 104 (third axis 303). At this time, if the sealing surface of the valve core 201 is subjected to pressure from the pipeline medium, this force will be transmitted to the roller 105 at its head end through the connecting rod 107. Since the direction of the force exerted by the roller 105 on the third track 403 is exactly perpendicular to the tangent of the track, that is, perpendicular to the direction of movement of the piston 104, and the pressure angle is 90°, this force cannot be decomposed into an effective component force to push the piston 104 to move along its axis. Therefore, the piston 104 is locked and cannot move, thereby realizing the bidirectional mechanical self-locking of the valve in the case of air cut-off, ensuring system safety.

[0039] Through the above specific embodiments, the vacuum butterfly valve of the present invention possesses key performance characteristics lacking in traditional pneumatic butterfly valves: 1. Extremely low particle generation level, meeting the requirements of high-cleanliness vacuum processes such as semiconductors and analytical instruments; 2. High reliability, with moving parts isolated from the contaminated environment and the valve core without bearing support, avoiding the risk of jamming; 3. Inherent mechanical self-locking function, maintaining the open or closed state even when the driving gas source fails, ensuring system safety. This ingenious design, through the combined piston motion and unique track coordination, achieves a composite action of translational release and rotary opening and closing of the valve core, ultimately achieving the various technical indicators of a high-performance vacuum valve.

[0040] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Modifications and variations made by those skilled in the art without departing from the spirit and scope of the invention should be within the protection scope of the appended claims.

Claims

1. A vacuum butterfly valve, comprising a cylinder assembly (1), a valve core assembly (2), and a valve body (3), wherein the valve core (201) of the valve core assembly (2) is disposed within the valve body (3), characterized in that: The cylinder assembly (1) includes a cylinder (102), a piston (104), a connecting rod (107), and a drive conversion mechanism; the piston (104) is movably disposed within the cylinder (102), and its inner and outer surfaces are provided with multiple tracks constructed with different geometric shapes; the drive conversion mechanism includes a fixing member fixed to the cylinder (102) and a driven member connected to the connecting rod (107); the fixing member cooperates with at least one track on the outer surface of the piston (104) to constrain the piston. The piston (104) generates an output motion that combines linear motion along its axis and rotational motion about its axis under drive; the driven member cooperates with at least another track on the inner surface of the piston (104) to convert the combined output motion of the piston (104) into the motion of the connecting rod (107); one end of the connecting rod (107) is connected to the driven member, and the other end drives the valve core (201) to perform a combined action of disengaging from or pressing against the valve seat and rotating.

2. A vacuum butterfly valve according to claim 1, characterized in that, The piston (104) has multiple tracks on its surface, including a first track (401) and a second track (402) on its outer cylindrical surface, and a third track (403) on its inner cylindrical surface; the fixing member is a special-shaped screw (103) that passes through the cylinder (102) and cooperates with the first track (401) and the second track (402); the driven member is a roller (105) located at the head end of the connecting rod (107), and the roller (105) is embedded in the third track (403).

3. A vacuum butterfly valve according to claim 2, characterized in that, The third track (403) includes, in sequence, a first straight segment parallel to the axis of the piston (104), an arc segment at an angle to the axis of the piston (104), a second straight segment parallel to the axis of the piston (104), and a third straight segment parallel to the axis of the piston (104) along the movement path from fully closed to fully open.

4. A vacuum butterfly valve according to claim 3, characterized in that, At the start and end of the first straight segment of the third track (403), the tangent direction of the third track (403) is parallel to the axis of the piston (104) so ​​that the valve achieves mechanical self-locking in the fully closed and fully open positions.

5. A vacuum butterfly valve according to claim 2, characterized in that, During the valve opening process, the first track (401) and the second track (402) sequentially include a first straight segment that guides the piston (104) to make a pure linear motion, a spiral segment that guides the piston (104) to rotate around its own axis by a predetermined angle while continuing to make a linear motion, and a second straight segment that guides the piston (104) to make a pure linear motion again.

6. A vacuum butterfly valve according to claim 5, characterized in that, The helical segment is a quarter helix, used to guide the piston (104) to rotate 90°.

7. A vacuum butterfly valve according to claim 2, characterized in that, It also includes a base (110) and a double-rotating block (109). The base (110) is connected to the cylinder (102) and is provided with a bearing. The double-rotating block (109) is connected to the middle of the connecting rod (107) by a pin and installed in the bearing, so that the connecting rod (107) can rotate around the bearing and can rotate around the pin. The base (110) is fixed to the end of the cylinder (102) by screws. The bearing is fixedly installed inside the base by a bearing limiting block (111) and screws. A sealing ring (108) is installed on the connecting rod (107) to achieve dynamic sealing between the connecting rod (107) and the cylinder (102). The cylinder assembly (1) also includes a cylinder head (101) connected to the cylinder (102). The cylinder head (101) and the cylinder (102) form a sealed cylinder cavity.

8. A vacuum butterfly valve according to claim 1, characterized in that, The valve core assembly (2) also includes a support ring (202) fitted on the valve core (201). The support ring (202) is made of a high polymer wear-resistant material and is used to support and guide the valve core (201) in the valve body (3). The tail end of the connecting rod (107) is fixedly connected to the valve core (201) of the valve core assembly (2) by screws. The valve core assembly (2) also includes a sealing ring (203) installed around the valve core (201). The sealing ring (203) is used to fit against the sealing seat of the valve body (3) to achieve sealing when the valve is closed. The support ring (202) is fitted on the valve core (201) and located inside the sealing ring (203). The support ring (202) is made of PEEK or POM high polymer wear-resistant material.

9. A vacuum butterfly valve according to claim 2, characterized in that, The connecting rod (107) has a roller (105) on each side of its head end. Both rollers (105) are embedded in the third track (403). The rollers (105) are mounted on the head end of the connecting rod (107) by means of a pin (106).

10. A control method for a vacuum butterfly valve according to any one of claims 1-9, characterized in that, The opening process of the vacuum butterfly valve includes the following four stages in sequence: In the first stage, the driving piston (104) moves in a straight line along its own axis, namely the third axis (303). At this time, the connecting rod (107) and the valve core (201) remain stationary, and the valve is in a closed and self-locking state. In the second stage, the driving piston (104) continues to move in a straight line along the third axis (303). In this stage, the connecting rod (107) rotates around the second axis (302), causing the valve core (201) to translate, so that the sealing ring (203) on it is separated from the valve seat of the valve body (3). In the third stage, while the driving piston (104) moves linearly along the third axis (303), it rotates around the third axis (303) by a predetermined angle. In this stage, the connecting rod (107) rotates around the first axis (301), thereby driving the valve core (201) to rotate inside the valve body (3) to open the valve. In the fourth stage, the drive piston (104) moves in a straight line along the third axis (303) again until it reaches the end of the stroke. At this time, the connecting rod (107) and the valve core (201) remain stationary, and the valve is in an open self-locking state. The closing process of the vacuum butterfly valve is the exact reverse of the opening process, and consists of the following four stages: In the first stage, the drive piston (104) starts from the end position of the valve opening and moves downward in a straight line along its own axis, namely the third axis (303). At this time, the connecting rod (107) and the valve core (201) remain stationary. In the second stage, while the driving piston (104) continues to move straight down along the third axis (303), it rotates in the opposite direction around the third axis (303) by the predetermined angle. In this stage, the connecting rod (107) rotates in the opposite direction around the first axis (301), thereby driving the valve core (201) to rotate in the opposite direction by 90° within the valve body (3) to achieve closure. In the third stage, the drive piston (104) continues to move downward in a straight line along the third axis (303). In this stage, the connecting rod (107) rotates in the opposite direction around the second axis (302), causing the valve core (201) to translate and press the sealing ring (203) on it against the valve seat of the valve body (3). In the fourth stage, the drive piston (104) continues to move downward in a straight line to the initial position, at which point the valve returns to the closed self-locking state.

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