Pneumatic execution device

Abstract

The utility model relates to the technical field of valves, in particular to a pneumatic execution device. Comprising a first air cylinder, the first air cylinder comprises a first air cylinder barrel, a first piston and a first piston rod, and the first piston rod reciprocates between a first stroke end point and a second stroke end point; the power output shaft and the first piston rod are coaxially arranged, and the power output shaft can reciprocate in the axial direction; the multi-connecting-rod mechanism is connected between the first piston rod and the power output shaft, the multi-connecting-rod mechanism has a self-locking state and an unlocking state which can be switched, and when the first piston rod moves to the first stroke end point, the multi-connecting-rod mechanism is switched to the self-locking state. Even if the air source pressure of the first air cylinder is reduced or disappears, the state of the valve cannot be changed, and the use safety of the valve is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of valves, in particular to a pneumatic actuating device. BACKGROUND

[0002] In recent years, with the continuous development of modernization, valve technology also needs to adapt to the development of new products, especially the valve control actuator suitable for pipeline transportation stations of special goods such as natural gas and oil, which needs to have the performance of energy saving, safety and reliability, and resistance to harsh working conditions.

[0003] The existing actuating mechanism is mostly electric, and small-current electrical equipment or pneumatic equipment is used as much as possible for safety needs. The existing pneumatic actuating device has high pressure requirements for the gas source during the switching process of the valve. The valve needs to be kept in a certain state for a long time, and the gas source needs to be real-time guaranteed within a certain pressure range. Only in this way, the pneumatic actuating device can output sufficient force or torque. Once the gas source pressure is insufficient, the pneumatic actuating device will retract, causing the valve to abnormally open or close, affecting the use effect of the valve. Therefore, there is an urgent need for a pneumatic actuating device that can maintain the open or closed state of the valve in the case of gas loss. CONTENT OF THE INVENTION

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present application provides a pneumatic actuating device.

[0005] The present application provides a pneumatic actuating device, comprising:

[0006] A first cylinder, the first cylinder comprising a first cylinder barrel, a first piston and a first piston rod, the first piston rod reciprocating between a first stroke end point and a second stroke end point;

[0007] A power output shaft coaxially arranged with the first piston rod, and the power output shaft can reciprocate in the axial direction;

[0008] A multi-link mechanism connected between the first piston rod and the power output shaft, the multi-link mechanism having a switchable self-locking state and an unlocked state, and when the first piston rod moves to the first stroke end point, the multi-link mechanism switches to the self-locking state.

[0009] In some embodiments, the multi-link mechanism comprises a fixed disc, a moving disc and a multi-link assembly, the fixed disc is fixedly connected with the outer end face of the first cylinder barrel, and the moving disc is connected with the power output shaft.

[0010] The multi-link assembly comprises two oppositely arranged two-link mechanical arms, an intermediate connecting arm and a swing arm connected between the two two-link mechanical arms, one end of the two-link mechanical arm is rotationally connected with the fixed disc, the other end is rotationally connected with the moving disc, and the intermediate connecting arm is fixed on the first piston rod.

[0011] In some embodiments, the two-link mechanical arm comprises a first connecting arm and a second connecting arm, the first connecting arm is L-shaped, and two ends of the first connecting arm are a first end and a second end respectively, two ends of the second connecting arm are a third end and a fourth end respectively, the corner of the first connecting arm is connected with the third end of the second connecting arm, the first end of the first connecting arm is rotationally connected with the fixed disc, the second end of the first connecting arm is rotationally connected with the swing arm, and the fourth end of the second connecting arm is rotationally connected with the moving disc.

[0012] In some embodiments, two ends of the intermediate connecting arm are rotationally connected with the second end of the first connecting arm through one swing arm.

[0013] In some embodiments, it further comprises a second cylinder and a spiral guide base, the second cylinder comprises a second cylinder barrel, a second piston and a second piston rod, the second cylinder barrel is located on the side of the multi-link body mechanism away from the first cylinder, the power output shaft passes through the second cylinder barrel along the axial direction of the second cylinder barrel, and the second piston rod is coaxially arranged with the power output shaft; the spiral guide base is fixedly arranged, a spiral groove is formed in the spiral guide base, a pin shaft is arranged on the outer wall of the second piston rod, and the pin shaft is slidably arranged in the spiral groove.

[0014] In some embodiments, a first limiting groove is arranged on the power output shaft along the axial direction of the power output shaft, a first limiting block is arranged on the inner wall of the second piston rod and slidably matched with the first limiting groove, so that the power output shaft and the second piston rod are relatively slidable in the axial direction and relatively fixed in the circumferential direction.

[0015] In some embodiments, a rotatable rolling sleeve is sleeved on the pin shaft, and the rolling sleeve is located in the spiral groove.

[0016] In some embodiments, it further comprises a connecting support, the connecting support is connected with the lower end of the second cylinder, a first chamber is arranged in the connecting support, the spiral guide base is coaxially arranged with the connecting support and fixedly arranged in the first chamber.

[0017] In some embodiments, the power output shaft and the moving disc are connected through a first matched friction pair, so that the power output shaft and the moving disc are relatively fixed in the axial direction and relatively rotatable in the circumferential direction.

[0018] In some embodiments, the second piston rod is connected to the second piston by a second pair of frictional surfaces to be axially fixed relative to each other and rotatable relative to each other in a circumferential direction.

[0019] Compared with the prior art, the technical scheme provided by the embodiments of the present application has the following advantages:

[0020] When the first piston rod moves to the first stroke end point, the multi-link mechanism switches to a self-locking state, and the form of the multi-link mechanism is fixed, which provides sufficient holding force for the power output shaft. Even if the gas source pressure of the first cylinder becomes smaller or disappears, the first piston and the power output shaft can be kept in the existing position in the self-locking state of the multi-link mechanism, and the power output shaft will not change the state of the valve. Therefore, even if the gas source pressure of the first cylinder becomes smaller or disappears, the state of the valve will not change, and the safety of the valve is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0022] In order to more clearly illustrate the technical schemes in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0023] Figure 1 A sectional view of the pneumatic actuator according to the embodiments of the present application;

[0024] Figure 2 A structural schematic view of the pneumatic actuator according to the embodiments of the present application;

[0025] Figure 3 A structural schematic view of the second piston according to the embodiments of the present application;

[0026] Figure 4 An axial view of the second piston according to the embodiments of the present application;

[0027] Figure 5 A structural schematic view of the power output shaft according to the embodiments of the present application;

[0028] Figure 6 An axial view of the power output shaft according to the embodiments of the present application.

[0029] Wherein, 1, the first cylinder; 2, the multi-connecting rod body mechanism; 3, the second cylinder; 4, the power output shaft; 5, the spiral guide base; 6, the connecting support; 7, the first matched friction pair; 8, the second matched friction pair; 9, the first mechanical switch; 10, the second mechanical switch; 11, the first cylinder barrel; 111, the first barrel body; 112, the first end cover; 113, the second end cover; 12, the first piston; 13, the first piston rod; 21, the two-connecting rod mechanical arm; 221, the first connecting arm; 212, the second connecting arm; 22, the intermediate connecting arm; 23, the swing arm; 2111, the first end; 2112, the second end; 2113, the corner; 24, the fixed disc; 25, the moving disc; 27, the connecting lug; 28, the connecting lug; 31, the second cylinder barrel; 32, the second piston; 33, the second piston rod; 311, the second barrel body; 312, the third end cover; 331, the pin shaft; 332, the first limiting block; 41, the first connecting section; 42, the second connecting section; 43, the third connecting section; 44, the fourth connecting section; 45, the fifth connecting section; 431, the first limiting groove; 51, the spiral groove. DETAILED DESCRIPTION

[0030] In order to enable the above-mentioned purposes, features and advantages of the present application to be more clearly understood, the scheme of the present application will be further described below. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0031] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein; obviously, the embodiments in the description are only some of the embodiments of the present application, not all the embodiments.

[0032] As shown in the drawings, Figures 1 to 6 The embodiments of the present application provide a pneumatic actuator, which is suitable for providing power for opening and closing of a valve.

[0033] Specifically, in some embodiments of the present application, the pneumatic actuator comprises a first cylinder 1, a multi-connecting rod body mechanism 2 and a power output shaft 4, the first cylinder 1 is connected with the power output shaft 4 through the multi-connecting rod body mechanism 2 to drive the power output shaft 4 to move, and the power output shaft 4 is connected with the valve to realize the opening and closing of the valve.

[0034] The first cylinder 1 includes a first cylinder barrel 11, a first piston 12 and a first piston rod 13. The first cylinder barrel 11 includes a first barrel body 111 with two open ends and first and second end covers 112 and 113 arranged at the two ends of the first barrel body 111. The first and second end covers 112 and 113 close the two ends of the first barrel body 111, forming a first cylinder 1 chamber inside the first barrel body 111. The first piston 12 is movably arranged in the first cylinder 1 chamber. One end of the first piston rod 13 is fixedly connected to the first piston 12, and the other end passes through the first cylinder 1 chamber from the second end cover 113. In use, the first barrel body 111 is arranged vertically, the first end cover 112 forms a top cover, and the second end cover 113 forms a bottom cover. The action of the first piston 12 is controlled by providing a gas source into the first cylinder 1 chamber. The first piston 12 reciprocates between the first and second end covers 112 and 113 under the action of the gas source pressure, thereby driving the first piston rod 13 to reciprocate between the first and second stroke end points. When the first piston rod 13 is at the first stroke end point, the first piston 12 moves to a position abutting against the first end cover 112. When the first piston rod 13 is at the second stroke end point, the first piston 12 moves to a position abutting against the second end cover 113.

[0035] The power output shaft 4 is coaxially arranged with the first piston rod 13 and is located below the first piston rod 13. The power output shaft 4 is connected to the first piston rod 13 through the multi-link mechanism 2. When the first piston rod 13 moves, it can drive the power output shaft 4 to reciprocate along the axial direction.

[0036] The multi-link mechanism 2 is connected between the first piston rod 13 and the power output shaft 4. Specifically, the lower end of the first piston rod 13 and the upper end of the power output shaft 4 are respectively connected to the multi-link mechanism 2. The multi-link mechanism 2 has a switchable self-locking state and an unlocked state. When the first piston rod 13 moves to the first stroke end point, the multi-link mechanism 2 switches to the self-locking state. The first piston 12 abuts against the second end cover 113, and the first piston rod 13 cannot continue to move downward. However, the multi-link mechanism 2 is in the self-locking state. At this time, when the gas source pressure of the first cylinder 1 decreases or disappears, the first piston 12 has a tendency to move upward. However, the first piston 12 remains at the second stroke end point, and the position of the power output shaft 4 remains unchanged due to the self-locking state of the multi-link mechanism 2. Therefore, even if the gas source pressure of the first cylinder 1 decreases or disappears, the state of the valve will not change, improving the safety of the valve in use.

[0037] Further, in some embodiments of the present application, the multi-link mechanism 2 comprises a fixed disc 24, a moving disc 25 and a multi-link assembly, the fixed disc 24 is fixedly connected with the outer end surface of the first cylinder barrel 11, and the moving disc 25 is connected with the power output shaft 4; the multi-link assembly comprises two oppositely arranged two-link mechanical arms 21 and an intermediate connecting arm 22 and a swing arm 23 connected between the two two-link mechanical arms 21, one end of the two-link mechanical arm 21 is fixedly connected with the fixed disc 24, and the other end is rotatably connected with the moving disc 25, and the intermediate connecting arm 22 is fixed on the first piston rod 13.

[0038] Specifically, the fixed disc 24 and the moving disc 25 are oppositely arranged, the fixed disc 24 is fixedly connected with the outer side surface of the second cylinder head, the moving disc 25 is connected with the power output shaft 4, the multi-link assembly is connected between the fixed disc 24 and the moving disc 25, and the self-locking state of the multi-link mechanism 2 is realized by the multi-link assembly.

[0039] The multi-link assembly comprises two oppositely arranged two-link mechanical arms 21, the two two-link mechanical arms 21 are symmetrically arranged about the axial direction of the power output shaft 4, the intermediate connecting arm 22 is located between the two two-link mechanical arms 21, one swing arm 23 is connected between the two ends of the intermediate connecting arm 22 and the two two-link mechanical arms 21 respectively, and the two ends of the swing arm 23 are rotatably connected with the intermediate connecting arm 22 and the two-link mechanical arm 21 respectively.

[0040] Through the arrangement of the multi-link assembly, the self-locking of the multi-link mechanism 2 can be realized, and the self-locking state can be unlocked by applying a larger force.

[0041] Specifically, the two-link mechanical arm 21 comprises a first connecting arm 221 and a second connecting arm 212, the first connecting arm 221 is L-shaped, and the two ends of the first connecting arm 221 are a first end 2111 and a second end 2112 respectively, the two ends of the second connecting arm 212 are a third end and a fourth end, the corner 2113 of the first connecting arm 221 is connected with the third end of the second connecting arm 212, the first end 2111 of the first connecting arm 221 is rotatably connected with the fixed disc 24, the second end 2112 of the first connecting arm 221 is rotatably connected with the swing arm 23, and the fourth end of the second connecting arm 212 is rotatably connected with the rotating disc.

[0042] Exemplarily, in some embodiments of the present application, a connecting lug 27 is arranged on the lower surface of the fixed disc 24, the first end 2111 of the first connecting arm 221 is rotatably connected to the connecting lug 27 through a pin shaft, a connecting lug 28 is arranged on the upper surface of the moving disc 25, and the fourth end of the second connecting arm 212 is rotatably connected to the connecting lug 28 through a pin shaft. The corner 2113 of the first connecting arm 221 is rotatably connected to the third end of the second connecting arm 212 through a pin shaft, and the two ends of the swing arm 23 are rotatably connected to the intermediate connecting arm 22 and the second end 2112 of the first connecting arm 221 through pin shafts. The intermediate connecting arm 22 is arranged perpendicularly to the first piston rod 13 and is fixedly connected to the end of the first piston rod 13.

[0043] When the first piston 12 moves to the position abutting against the second end cover 113, the long arm segment of the first connecting arm 221 and the second connecting arm 212 are arranged in the vertical direction, the short arm segment of the first connecting arm 221 is arranged in the horizontal direction, the swing arm 23 and the intermediate connecting arm 22 are in the same straight line as the short arm of the first connecting arm 221, and the two ends of the intermediate connecting arm 22 abut against the second end 2112 of the first connecting arm 221 to fix the intermediate connecting arm 22 at the position. Due to the interaction between the connecting arms, the self-locking of the multi-link mechanism 2 is realized. Even if the gas source pressure in the first cylinder 1 disappears, the first piston 12 will not retract, and the valve state can remain unchanged.

[0044] Further, in some embodiments of the present application, the pneumatic actuating device further comprises a second cylinder 3, which comprises a second cylinder barrel 31, a second piston 32 and a second piston rod 33. The second cylinder barrel 31 is located on the side of the multi-link mechanism 2 away from the first cylinder 1, that is, below the multi-link mechanism 2. The power output shaft 4 passes through the second cylinder barrel 31 in the axial direction of the second cylinder barrel 31, and the second piston rod 33 is coaxially arranged on the outer wall of the power output shaft 4 and is sleeved on the outer wall of the power output shaft 4; a spiral guide base 5 is sleeved on the outer side wall of the second piston rod 33, the spiral guide base 5 is fixedly arranged, a spiral groove 51 is formed in the spiral guide base 5, and a pin shaft 331 is arranged on the outer wall of the second piston rod 33 and slidably arranged in the spiral groove 51.

[0045] The movement of the second piston 32 is powered by the gas source pressure of the second cylinder 3. When the second piston 32 moves downward, the second piston rod 33 is driven to move downward. Since the second piston rod 33 is slidably connected to the spiral groove 51 through a pin shaft, the second piston rod 33 will also rotate during the downward movement of the second piston rod 33, thereby driving the power output shaft 4 to rotate and realizing the control of the multi-way valve.

[0046] Specifically, the rotation angle and length of the spiral groove 51 can be designed by different valves. Taking a four-way valve as an example, the power output shaft 4 needs to be switched between four positions, and the two ends of the spiral groove 51 are different by 90 degrees along the circumference of the spiral guide seat 5. During the process that the pin shaft slides from one end of the spiral groove 51 to the other end, the power output shaft 4 rotates by 90 degrees. The spiral groove 51 can be arranged along the clockwise spiral or the counterclockwise spiral.

[0047] The number of spiral grooves 51 is one or more, and a plurality of pin shafts are correspondingly arranged on the outer wall of the second piston rod 33 to slide with the plurality of spiral grooves 51. The spiral groove 51 plays a role of guiding the rotation of the second piston rod 33 and the power output shaft 4, converts linear motion into rotary motion, and meets the reversing requirements of the valve.

[0048] Further, in some embodiments of the present application, a rotatable roller is sleeved on the pin shaft 331, the roller is located in the spiral groove 51, the pin shaft 331 is fixedly arranged on the outer side wall of the second piston rod 33, and the roller is rotatably sleeved on the pin shaft 331. When the pin shaft 331 moves into the spiral groove 51, the roller rotates relative to the pin shaft 331, thereby reducing the friction between the pin shaft 331 and the spiral groove 51.

[0049] In some embodiments of the present application, the power output shaft 4 and the second piston rod 33 are slidably matched through key grooves. Specifically, as shown in Figure 5 The power output shaft 4 includes a first connecting segment 41, a second connecting segment 42, a third connecting segment 43, a fourth connecting segment 44 and a fifth connecting segment 45 arranged in sequence along the axial direction, wherein the diameters of the first connecting segment 41 to the third connecting segment 43 increase in sequence, the diameters of the third connecting segment 43 to the fifth connecting segment 45 decrease in sequence, a first limiting groove 431 is arranged on the outer side wall of the third connecting segment 43, the first limiting groove 431 is arranged along the axial direction, and a plurality of first limiting grooves 431 are arranged along the circumference. The second piston rod 33 is a sleeve structure, and includes a first sleeve segment and a second sleeve segment. The diameter of the first sleeve segment is smaller than that of the second sleeve segment, and the first sleeve segment is matched with the first piston 12. The second sleeve segment is located below the second piston 32, and a first limiting block 332 is arranged on the inner wall of the second sleeve segment. The first limiting block 332 is arranged in one-to-one correspondence with the first limiting groove 431. The cooperation between the first limiting block 332 and the first limiting groove 431 can make the power output shaft 4 relatively move along the axial direction and be relatively fixed along the circumference with respect to the second piston rod 33.

[0050] Further, in some embodiments of the present application, the pneumatic actuator further includes a connecting support 6 and a supporting cylinder. The connecting support 6 is connected with the lower end of the second cylinder 3, the first chamber is arranged in the connecting support 6, the spiral guide seat 5 is coaxially arranged with the connecting support 6 and fixedly arranged in the first chamber.

[0051] Specifically, the second cylinder barrel 31 comprises a second barrel body and a third end cover 312, both ends of the second barrel body are open, the third end cover 312 is arranged at the upper end of the second barrel body, the lower end of the second barrel body is connected with the connecting support 6, the upper end surface of the connecting support 6 serves as the lower end cover of the second cylinder 3, the second piston 32 reciprocates between the third end cover 312 and the connecting support 6, in the process of movement of the second piston 32, the second piston rod 33 moves linearly and rotates with the second piston 32, and further drives the power output shaft 4 to rotate, so as to realize the reversing of the valve.

[0052] The power output shaft 4 and the moving disc 25 are connected through the first paired friction pair 7, so that the power output shaft 4 and the moving disc 25 are relatively fixed in the axial direction and can relatively rotate in the circumferential direction.

[0053] The second piston rod 33 and the second piston 32 are connected through the second paired friction pair 8, so that the second piston rod 33 and the second piston 32 are relatively fixed in the axial direction and can relatively rotate in the circumferential direction.

[0054] Both the first paired friction pair 7 and the second paired friction pair 8 can adopt a structure similar to a bearing to realize the relative fixation in the axial direction and the relative rotation in the circumferential direction.

[0055] That is to say, when the power output shaft 4 moves in the axial direction, the moving disc 25 moves in the axial direction with the power output shaft 4, when the second piston rod 33 moves in the axial direction, the second piston 32 moves in the axial direction with the second piston rod 33, in the process of movement in the axial direction, the second piston rod 33 rotates along the helical groove 51, and further drives the power output shaft 4 to rotate, so as to realize the reversing of the valve.

[0056] Further, in some embodiments of the present application, the first mechanical switch 9 is arranged on the first end cover 112 of the first cylinder 1, the second mechanical switch 10 is arranged on the third end cover 312 and the fourth end cover of the second cylinder 3, the first mechanical switch 9 is used to be triggered when the first piston 12 moves to the position in contact with the first end cover 112, and the second mechanical switch 10 is used to be triggered when the second piston 32 moves to the position in contact with the third end cover 312 and the fourth end cover.

[0057] When the first piston 12 moves downward, the middle connecting arm 22 of the multi-link mechanism 2 is pushed to move downward, and when approaching the end of the stroke (i.e., close to the second end cover 113), the moving plate 25 of the multi-link mechanism 2 will transmit an action force to the power output shaft 4 which is tens of times larger than the output force of the first piston 12, and vice versa. Because the stroke of the first piston 12 is slightly larger than the end stroke of the multi-link mechanism 2, the first piston rod 13 will be subjected to a downward resultant force based on the structural characteristics of the multi-link mechanism 2, so that the first piston 12 is in contact with the first end cover 112, and the power output shaft 4 can maintain sufficient action force to achieve a self-locking state even if the air source of the first cylinder 1 is lost.

[0058] The action sequence of the pneumatic actuating device in use is described as follows: in the initial state, the first piston 12 is kept in the lower position (the position where the first piston 12 is in contact with the second end cover 113), the multi-link mechanism 2 is in the self-locking state, and the second piston 32 can be kept at either end. When the valve needs to be reversed, the first piston 12 first moves upward, and after reaching the top, the first mechanical switch at the upper end is opened, and then the second piston 32 can move to the other end as needed. The movement of the second piston 32 converts the linear motion into rotary motion through the screw guide 5, so as to achieve the reversing requirement of the valve. After the second piston 32 moves to the other end, the corresponding second mechanical switch is opened, and the first piston 12 is controlled to move downward, so as to again achieve the end self-locking state of the power output shaft 4, that is, the closed state of the valve. The pneumatic actuating device provided in the embodiment of the application can fix the state of the valve through the self-locking of the first cylinder 1 and the multi-link mechanism 2, so that even if the air source pressure of the first cylinder 1 decreases or disappears, the state of the valve will not change; and the linear motion is converted into rotary motion through the second cylinder 3 and the screw guide 5, so as to achieve the reversing requirement of the valve.

[0059] It should be noted that, in the present document, relational terms such as“first” and“second”, and the like, can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms“comprises”,“comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by“comprises a...” does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0060] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to these embodiments without departing from the spirit and scope of the application. It is intended that the scope of the application should not be limited by the particular representative embodiments described above.

Claims

1. A pneumatic actuator, characterized in that The utility model relates to a kind of multi-rod mechanism and the power output shaft of first cylinder, comprising: First cylinder, the first cylinder includes first cylinder barrel, first piston and first piston rod, the first piston rod reciprocates between first stroke end point and second stroke end point; Power output shaft, coaxially arranged with the first piston rod, and the power output shaft can reciprocate in axial direction; Multi-rod mechanism, connected between the first piston rod and the power output shaft, the multi-rod mechanism has switchable self-locking state and unlocking state, the multi-rod mechanism switches to self-locking state when the first piston rod moves to the second stroke end point.

2. The pneumatic actuator according to claim 1, characterized in that The multi-rod mechanism includes fixed disc, moving disc and multi-link assembly, the fixed disc is fixedly connected with the outer end surface of the first cylinder barrel, and the moving disc is connected with the power output shaft; The multi-link assembly includes two oppositely arranged two-link mechanical arms, and an intermediate connecting arm and a swing arm connected between the two two-link mechanical arms, one end of the two-link mechanical arm is rotatably connected with the fixed disc, and the other end is rotatably connected with the moving disc, and the intermediate connecting arm is fixed on the first piston rod.

3. The pneumatic actuator of claim 2, wherein, The two-link mechanical arm includes a first connecting arm and a second connecting arm, the first connecting arm is L-shaped, and the two ends of the first connecting arm are a first end and a second end respectively, the two ends of the second connecting arm are a third end and a fourth end respectively, the corner of the first connecting arm is connected with the third end of the second connecting arm, the first end of the first connecting arm is rotatably connected with the fixed disc, the second end of the first connecting arm is rotatably connected with the swing arm, and the fourth end of the second connecting arm is rotatably connected with the moving disc.

4. The pneumatic actuator of claim 3, wherein, The two ends of the intermediate connecting arm are rotatably connected with the second end of the first connecting arm through a swing arm.

5. The pneumatic actuator of claim 3, wherein, It also includes a second cylinder and a spiral guide base, the second cylinder includes a second cylinder barrel, a second piston and a second piston rod, the second cylinder barrel is located on the side of the multi-rod mechanism away from the first cylinder, the power output shaft passes through the second cylinder barrel in the axial direction of the second cylinder barrel, and the second piston rod is coaxially arranged with the power output shaft;The spiral guide base is fixedly arranged, and a spiral groove is formed in the spiral guide base, a pin shaft is arranged on the outer wall of the second piston rod, and the pin shaft is slidably arranged in the spiral groove.

6. The pneumatic actuator of claim 5, wherein, A first limiting groove is arranged on the power output shaft in the axial direction of the power output shaft, a first limiting block is arranged on the inner wall of the second piston rod and can slide with the first limiting groove, so that the power output shaft and the second piston rod can slide relative to each other in the axial direction and can be fixed relative to each other in the circumferential direction.

7. The pneumatic actuator of claim 5, wherein, A rotatable rolling sleeve is arranged on the pin shaft, and the rolling sleeve is located in the spiral groove.

8. The pneumatic actuator of claim 5, wherein, It also includes a connecting support, the connecting support is connected with the lower end of the second cylinder, and a first chamber is arranged in the connecting support, the spiral guide base is coaxially arranged with the connecting support and fixedly arranged in the first chamber.

9. The pneumatic actuator of claim 2, wherein, The power output shaft and the moving disc are connected through a first matched friction pair, so that the power output shaft and the moving disc are relatively fixed in the axial direction and can relatively rotate in the circumferential direction.

10. The pneumatic actuator of claim 5, wherein, The second piston rod and the second piston are connected through a second matched friction pair, so that the second piston rod and the second piston are relatively fixed in the axial direction and can relatively rotate in the circumferential direction.

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