Three-section type pneumatic actuator
Through the design of the clamping assembly and the damping assembly, combined with the locking assembly, the positioning deviation problem caused by the main piston hitting the auxiliary piston is solved, the precise and stable positioning of the actuator's intermediate state is achieved, and the accuracy of flow control is improved.
Patent Information
- Application Number
- CN202511190987.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-25
- Publication Date
- 2025-09-26
AI Technical Summary
When the main piston of an existing three-stage pneumatic actuator moves at high speed, the main piston hits the auxiliary piston, causing the mechanical limit to fail, causing the middle angle of the valve to deviate from the preset value, affecting the flow control accuracy.
The clamping assembly and the damping assembly are used in combination to automatically control the clamping state of the main piston and the push rod through the air pressure difference. The damping assembly changes the contact state of the adjustment part and the cylinder body according to the surrounding pressure environment. The locking assembly locks the position of the auxiliary piston to prevent the main piston from displacement or vibration after impact.
It effectively suppresses the impact energy of the main piston, improves the accuracy and stability of the actuator's intermediate state, ensures the accuracy of valve positioning, and prevents deviation in the actuator's intermediate state.
Smart Images
Figure CN120701804A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of actuators, and in particular to a three-stage pneumatic actuator. Background Art
[0002] A pneumatic actuator is an automated device that converts the energy of compressed air into mechanical motion. It is mainly used to control the opening and closing, adjustment and positioning of valves (such as ball valves and butterfly valves) or mechanical equipment. Among pneumatic actuators, three-stage pneumatic actuators are widely used in many fields.
[0003] Three-stage pneumatic actuators are widely used in the field of industrial valve control. They achieve segmented positioning of the valve from 0° to the middle angle - 90° (or 0°-90°-180°) through the coordinated movement of the auxiliary piston and the main piston. They are particularly suitable for scenarios such as quantitative loading and precise flow control.
[0004] In the existing technology, the positioning of the intermediate state is usually achieved by the mechanical limit of the auxiliary piston; when the actuator needs to switch to the intermediate state (such as 45°), the air source drives the auxiliary piston to move to the preset limit point, and the air pressure difference at both ends of the auxiliary piston is used to form a brake; then the main piston moves rapidly toward the auxiliary piston under the action of air pressure and stops at the limit of the auxiliary piston, so that the actuator is in the intermediate state, so that the valve can be positioned at the intermediate angle.
[0005] Similar to the above-mentioned existing technology, although it can achieve the positioning of the middle angle of the valve, the main piston of the actuator will violently collide with the positioned auxiliary piston during high-speed movement. The impact force may cause the auxiliary piston to displace or vibrate after the collision, resulting in failure of the preset mechanical limit. The main piston cannot be accurately docked due to inertia, and the actual angle of the valve deviates from the preset value (for example, the set 45° actually becomes 50°), causing a series of problems such as flow calculation errors in the quantitative control system.
[0006] Therefore, in order to solve the above problems, the present invention proposes a three-stage pneumatic actuator, which aims to suppress the impact energy of the main piston and improve the accuracy of the intermediate state of the actuator. Summary of the Invention
[0007] The purpose of the present invention is to provide a three-stage pneumatic actuator, which aims to suppress the impact energy of the main piston, eliminate the displacement or vibration of the auxiliary piston after being hit, and solve the problem of deviation between the intermediate state of the actuator and the setting.
[0008] To achieve the above objectives, the present invention adopts the following technical solution: a three-stage pneumatic actuator, comprising a cylinder, a transmission shaft, a primary piston, and an auxiliary piston, wherein the primary piston is capable of driving the transmission shaft to rotate, a push rod is provided between the primary piston and the auxiliary piston, and an adjusting member is provided on the side of the auxiliary piston away from the primary piston, further comprising: A clamping assembly is provided on the main piston, and the clamping assembly can change the clamping state of the main piston and the push rod according to the air pressure difference on both sides of the main piston; The damping assembly is arranged on the adjusting member and can change the contact state between the adjusting member and the cylinder body according to the surrounding pressure environment to achieve the positioning and relaxation of the auxiliary piston.
[0009] Preferably, the clamping assembly includes a clamping piece, and a clamping cavity for the clamping piece to move is provided in the main piston.
[0010] Preferably, the push rod is provided with a clamping groove cooperating with the clamping piece, and a communicating hole is further provided in the main piston, and the communicating hole connects the clamping cavity and the chamber of the main piston away from the push rod.
[0011] Preferably, the damping assembly includes a damping block, and the adjusting member is provided with a moving cavity for the damping block to move.
[0012] Preferably, one end of the adjusting member is connected to the auxiliary piston, and the other end extends out of the cylinder body. The part of the adjusting member extending out of the cylinder body is sleeved with an adjusting nut. The damping assembly also includes an air ventilation channel, which connects the moving cavity and the cavity of the auxiliary piston away from the push rod.
[0013] Preferably, a limit block is provided on the transmission shaft, and the actuator further comprises a limit assembly, which can limit and maintain the limit state of the transmission shaft through the limit block, and release the limit on the transmission shaft after the air pressure changes.
[0014] Preferably, the limit assembly includes two limit rods, each of which is provided with a fixing nut connected to the cylinder body, a telescopic cylinder is provided on the outer sleeve of the limit rod, and a sliding member hinged to the telescopic cylinder is provided at one end of the telescopic cylinder away from the fixing nut, and a sliding groove is provided on the limit block, and the sliding member is slidably connected to the limit block through the sliding groove.
[0015] Preferably, the limiting rod is provided with a limiting part and a moving part which are slidably connected thereto, and the telescopic cylinder is provided with a limiting groove which cooperates with the limiting part. The sliding of the moving part can change the contact state of the limiting part and the telescopic cylinder, and the moving part can move according to the change of air pressure in the cylinder.
[0016] Preferably, a locking assembly is further included, the locking assembly is located at the end of the cylinder body, and multiple groups of the locking assembly are provided around the adjusting member, and the locking assembly can lock the position of the adjusting member.
[0017] Preferably, the locking assembly includes a locking member and a driving member hinged to each other, the locking member is connected to the cylinder body, the driving member passes through the cylinder body and is slidably connected to the cylinder body, and the driving member is outer-circuited with a third elastic member.
[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention solves the problem of displacement of the intermediate state of the actuator through the cooperation of the damping component and the clamping component. The damping component fixes the auxiliary piston in the intermediate state, the clamping component reduces the impact force of the main piston on the push rod, and connects the main piston with the auxiliary piston, locking the intermediate state of the actuator, solving the problem of displacement or vibration of the main piston due to its impact force; the locking component further locks the position of the auxiliary piston and locks the intermediate state, while preventing the auxiliary piston from being displaced or vibrated after being hit by the main piston, preventing deviation of the intermediate state of the actuator, and ensuring the accuracy of the intermediate state of the actuator; the limit component can complete the locking and unlocking of the fully open state and the fully closed state of the actuator according to the change of air pressure, ensuring the accuracy and stability of each state of the actuator. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention.
[0020] Figure 2 It is a cross-sectional view of the pneumatic actuator of the present invention.
[0021] Figure 3 This invention Figure 2 A partial enlarged view of point A in the middle.
[0022] Figure 4 It is a schematic diagram of the clamping assembly and the damping assembly in the present invention.
[0023] Figure 5 This invention Figure 4 A partial enlarged view of point B in the middle.
[0024] Figure 6 This invention Figure 4 A partial enlarged view of point C in the middle.
[0025] Figure 7 It is a structural diagram of the limiting component in the present invention.
[0026] Figure 8 It is a schematic diagram of the position of the limit assembly when the actuator is in the fully open state in the present invention.
[0027] Figure 9 This invention Figure 8 A partial enlarged view of point D in the middle.
[0028] Figure 10 It is a structural schematic diagram of the limit assembly when the actuator is in the intermediate state in the present invention.
[0029] Figure 11 This invention Figure 10 A partial enlarged view of point E in the middle.
[0030] Figure 12It is a structural schematic diagram of the limit assembly when the actuator is in the fully closed state in the present invention.
[0031] Reference numerals: 1. Cylinder body; 11. End cover; 12. Partition plate; 13. First chamber; 131. First air port; 14. Second chamber; 141. Second air port; 15. Third chamber; 151. Third air port; 16. Fourth chamber; 161. Fourth air port; 17. Air passage; 2. Drive shaft; 21. Limit block; 211. Slideway; 3. Limiting assembly; 31. Limiting rod; 311. First limiting rod; 312. Second limiting rod; 32. Movable chamber; 33. Limiting member; 34. Moving member; 341. Driving member; 342. Piston member; 343. Interference member; 35. First elastic member; 36. Second elastic member; 37. Telescopic cylinder; 371. Limiting groove; 38. Sliding member; 39. Fixing nut; 4. Main piston; 41. Clamping assembly; 411. Clamping member; 412. Clamping chamber; 42. Communication hole; 5. Auxiliary piston; 6. Push rod; 61. Snap-fit slot; 7. Adjusting member; 71. Damping assembly; 711. Damping block; 712. Moving cavity; 713. Ventilation channel; 72. Adjusting nut; 8. Locking assembly; 81. Locking member; 82. Driving member; 83. Third elastic member. DETAILED DESCRIPTION
[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0033] Example 1 In order to eliminate the displacement or vibration of the auxiliary piston 5 after being hit and improve the accuracy and stability of the intermediate state of the actuator, Figures 1 to 12 As shown, the present invention proposes a three-stage pneumatic actuator, including a cylinder body 1, a transmission shaft 2, a main piston 4 and an auxiliary piston 5. The transmission shaft 2 is rotatably connected to the cylinder body 1, the main piston 4 can drive the transmission shaft 2 to rotate, the auxiliary piston 5 is located on the side of the main piston 4 away from the transmission shaft 2, a push rod 6 is provided between the main piston 4 and the auxiliary piston 5, the main piston 4 and the auxiliary piston 5 are slidably connected to the cylinder body 1, and an adjusting member 7 is provided on the side of the auxiliary piston 5 away from the main piston 4. The three-stage pneumatic actuator also includes a clamping assembly 41 and a damping assembly 71.
[0034] The cylinder body 1 includes an end cover 11 and a partition 12. The end cover 11 is located at both ends of the cylinder body 1. There are also two partitions 12, which are located inside the cylinder body 1 and between the main piston 4 and the auxiliary piston 5. There are two main pistons 4 and two auxiliary pistons 5. The partition 12, the main piston 4 and the auxiliary piston 5 divide the cavity in the cylinder body 1 into multiple chambers, namely: a first chamber 13 located between the two main pistons 4, a second chamber 14 between the main piston 4 and the partition 12, a third chamber 15 between the partition 12 and the auxiliary piston 5, and a fourth chamber 16 between the auxiliary piston 5 and the end cover 11; the first chamber 13 is provided with a first air port 131 communicating with the outside world, the second chamber 14 is provided with a second air port 141 communicating with the outside world, the third chamber 15 is provided with a third air port 151 communicating with the outside world, and the fourth chamber 16 is provided with a fourth air port 161 communicating with the outside world.
[0035] The transmission shaft 2 can be driven by gears, and the motion conversion is completed between the transmission shaft 2 and the main piston 4 through gear meshing, converting the linear motion of the main piston 4 into the rotational motion of the transmission shaft 2. The push rod 6 and the adjusting member 7 are respectively located on both sides of the auxiliary piston 5. The push rod 6 and the adjusting member 7 are fixedly connected to the auxiliary piston 5. The push rod 6 passes through the partition 12 and can contact the main piston 4. The adjusting member 7 passes through the end cover 11 and extends out of the cylinder body 1.
[0036] Both ends of the transmission shaft 2 extend out of the cylinder body 1. One end of the transmission shaft 2 is provided with an angle display device, which can display the rotation angle of the transmission shaft 2 in real time; the other end of the transmission shaft 2 is connected to a valve, and the opening state of the valve is controlled by the rotation angle of the transmission shaft 2.
[0037] The clamping assembly 41 is arranged on the main piston 4. The clamping assembly 41 can change the clamping state of the main piston 4 and the push rod 6 according to the air pressure difference on both sides of the main piston 4; the clamping assembly 41 changes the connection state of the main piston 4 and the push rod 6 according to the air pressure difference, thereby realizing automatic control of power transmission.
[0038] The clamping assembly 41 includes a clamping part 411, which is located at the position where the main piston 4 contacts the push rod 6. A clamping cavity 412 is provided in the main piston 4 for the clamping part 411 to move. The clamping part 411 can adjust the pressure difference on both sides of the main piston 4.
[0039] The push rod 6 is provided with a clamping groove 61 that cooperates with the clamping piece 411 , and the main piston 4 is further provided with a communicating hole 42 , which connects the clamping cavity 412 with the chamber of the main piston 4 away from the push rod 6 .
[0040] Multiple clamping parts 411 can be provided along the circumference of the connecting hole 42, and an annular cavity can be provided on the side of the main piston 4 close to the push rod 6. The end of the push rod 6 close to the main piston 4 can be provided with a convex ring corresponding to the annular cavity, and the clamping groove 61 can be provided on the inner side of the convex ring. The clamping part 411 can be provided on the annular cavity corresponding to the clamping groove 61. The cooperation between the annular cavity and the convex ring can improve the stability of the clamping between the main piston 4 and the push rod 6.
[0041] The connecting hole 42 connects the clamping groove 61 and the first chamber 13, and the clamping member 411 can clamp the push rod 6 to the main piston 4; at the same time, the clamping member 411 can also reduce the collision of the main piston 4 on the push rod 6. When the push rod 6 hits the clamping member 411, the clamping member 411 decomposes the force given by the push rod 6, forming a part of the force that pushes the clamping member 411 to move toward the axial direction of the main piston 4, thereby reducing the collision of the push rod 6.
[0042] When the actuator moves to the intermediate state, the auxiliary piston 5 moves into position, increasing the air pressure in the first chamber 13 to move the main piston 4 toward the push column. At this time, the air pressure in the first chamber 13 is greater than that in the second chamber 14. Because the clamping chamber 412 is connected to the first chamber 13, the clamping member 411 is pushed by the air pressure, causing the clamping member 411 to protrude from the main piston 4. When the main piston 4 contacts the push rod 6, the push rod 6 squeezes the clamping member 411 to slow down the main piston 4. When the main piston 4 moves into position, the clamping member 411 cooperates with the clamping groove 61 of the push rod 6 to clamp the push rod 6 and the main piston 4.
[0043] When the air pressure in the first chamber 13 decreases and the air pressure in the second chamber 14 increases, and the air pressure in the second chamber 14 is higher than that in the first chamber 13 , the clamping member 411 is pressed back into the main piston 4 by the air pressure difference, and the clamping relationship between the main piston 4 and the push rod 6 is released.
[0044] The clamping assembly 41 automatically switches the connection state between the push rod 6 and the main piston 4 depending on the air pressure difference. The connecting hole 42 transmits the air pressure to the clamping chamber 412, pushing the clamping component 411 to move, thereby realizing automatic clutching of the main piston 4 and the push rod 6, avoiding the inertial impact caused by mechanical limit and improving the response accuracy.
[0045] The damping assembly 71 is provided on the adjusting member 7 and can change the contact state between the adjusting member 7 and the cylinder 1 according to the surrounding pressure environment to achieve the positioning and release of the auxiliary piston 5. The damping assembly 71 adjusts the positioning and release of the auxiliary piston 5 to enhance system stability.
[0046] The damping assembly 71 includes a damping block 711 . A moving cavity 712 for the damping block 711 to move is provided in the adjusting member 7 . The damping block 711 can move in the moving cavity 712 to change the contact state with the cylinder 1 according to the surrounding air pressure state.
[0047] One end of the adjusting member 7 is connected to the auxiliary piston 5, and the other end extends out of the cylinder body 1. The part of the adjusting member 7 extending out of the cylinder body 1 is sleeved with an adjusting nut 72. The damping assembly 71 also includes a ventilation channel 713, which connects the moving cavity 712 and the cavity of the auxiliary piston 5 away from the push rod 6.
[0048] The ventilation channel 713 connects the movable chamber 712 and the fourth chamber 16. One end of the ventilation channel 713 connected to the fourth chamber 16 can be provided on the auxiliary piston 5, so as to avoid the strength reduction of the adjusting member 7 due to the opening. The damping block 711 can move radially along the adjusting member 7. The damping block 711 can contact the end cover 11 of the cylinder body 1. The end cover 11 is provided with a sleeve that is sleeved outside the adjusting member 7, so that after the adjusting member 7 adjusts the position of the auxiliary piston 5, the damping block 711 can still contact the cylinder body 1.
[0049] When the actuator moves toward the intermediate state, the adjusting nut 72 has been adjusted to the set position, and the air pressure in the fourth chamber 16 is increased through the fourth air port 161, pushing the auxiliary piston 5 toward the main piston 4, and the push rod 6 and the adjusting member 7 move synchronously. At this time, the movement of the auxiliary piston 5 increases the volume of the fourth chamber 16, so that the air pressure in the fourth chamber 16 will not be in a particularly high state, the damping block 711 will not be pushed by the air pressure, and the damping block 711 will not contact the end cover 11 of the cylinder body 1, so that the movement at this time is smooth; when the adjusting member When the adjusting nut 72 of 7 contacts the end cover 11, the adjusting nut 72 prevents the adjusting member 7, the auxiliary piston 5 and the push rod 6 from moving, and the auxiliary piston 5 moves into place. At this time, the air pressure in the fourth chamber 16 increases, and the auxiliary piston 5 continues to apply force toward the main piston 4, reducing the displacement caused by the main piston 4 colliding with the push rod 6; at the same time, the high pressure in the fourth chamber 16 causes the damping block 711 to move, squeezing the inner side wall of the sleeve of the end cover 11, so that a damping effect is formed between the adjusting member 7 and the end cover 11, preventing the main piston 4 from being displaced when colliding with the push rod 6.
[0050] When the actuator exits the intermediate state and the engagement between the main piston 4 and the push rod 6 is released, the air pressure in the third chamber 15 is increased and the air pressure in the fourth chamber 16 is reduced through the third air port 151 and the fourth air port 161, so that the damping block 711 of the damping assembly 71 is disengaged from the cavity, preventing the auxiliary piston 5 from getting stuck when moving.
[0051] The damping assembly 71 connects the movable chamber 712 and the fourth chamber 16 through the ventilation channel 713. The contact force between the damping block 711 and the cylinder body 1 is adjusted according to the air pressure in the fourth chamber 16. When the air pressure in the fourth chamber 16 is high, the damping block 711 is subjected to the air pressure and squeezes the inner wall of the chamber, thereby increasing the friction between the adjusting member 7 and the cylinder body 1 and making the auxiliary piston 5 more stably positioned; when the air pressure in the fourth chamber 16 is low, the damping block 711 is no longer subjected to the force of squeezing toward the cylinder body 1, and the damping block 711 can be detached from the cylinder body 1 at any time, thereby reducing the friction between the adjusting member 7 and the cylinder body 1 and avoiding jamming of the auxiliary piston 5 when moving.
[0052] The actuator also includes a locking assembly 8 located at the end of the cylinder 1. Multiple locking assemblies 8 are symmetrically distributed around the adjusting member 7. These assemblies automatically lock the position of the adjusting member 7 when the actuator is in an intermediate state, preventing deviations from the intermediate state due to fluctuations.
[0053] The locking assembly 8 includes a locking member 81 and a driving member 82 that are hinged to each other. The locking member 81 is connected to the cylinder body 1. The driving member 82 passes through the cylinder body 1 and is slidably connected to the cylinder body 1. A third elastic member 83 is provided on the outer sleeve of the driving member 82. One end of the third elastic member 83 is connected to the cylinder body 1, and the other end is connected to the driving member 82.
[0054] The locking member 81 is hinged on the outside of the end cover 11. The locking member 81 can be an L-shaped elastic plate. The driving member 82 passes through the end cover 11 of the cylinder body 1 and is slidably connected to the end cover 11. Both ends of the driving member 82 are provided with convex rings, which can limit the sliding stroke of the driving member 82 in the end cover 11 and prevent the driving member 82 from falling off the end cover 11. The third elastic member 83 is connected to the convex ring of the driving member 82 located on the outside of the cylinder body 1; the locking member 81 includes a connecting part, and the connecting part of the locking member 81 is hinged to the driving member 82. The driving member 82 is provided with an ear plate, and a waist-shaped groove is opened on the ear plate. The hinge axis of the locking member 81 and the driving member 82 can slide in the waist-shaped groove.
[0055] When the actuator moves toward the intermediate state, the adjusting nut 72 has been adjusted to the set position, and the air pressure in the fourth chamber 16 is increased through the fourth air port 161, pushing the auxiliary piston 5 toward the main piston 4, and the push rod 6 and the adjusting member 7 move synchronously. Due to the increase in the air pressure in the fourth chamber 16, the driving member 82 of the locking assembly 8 is driven by the pressure difference between the inside and outside of the cylinder 1, and the driving member 82 moves toward the outside of the cylinder 1, thereby driving the locking member 81 to rotate, so that the locking member 81 reaches the locked state. When the adjusting nut 72 of the adjusting member 7 is aligned with the end cover When the end cap 11 is about to contact, the adjusting nut 72 squeezes the locking piece 81, causing the locking piece 81 to deform, and the adjusting nut 72 contacts the outside of the end cap 11. The locking piece 81 recovers and applies a force to the adjusting nut 72 to prevent it from returning. The adjusting nut 72 prevents the adjusting piece 7, the auxiliary piston 5 and the push rod 6 from moving, and the auxiliary piston 5 moves into place. At this time, the air pressure in the fourth chamber 16 increases, and the driving piece 82 of the locking assembly 8 continuously applies a force to lock the adjusting nut 72 on the locking piece 81, thereby ensuring that the position of the auxiliary piston 5 does not deviate.
[0056] When the actuator releases the lock of the locking assembly 8 on the auxiliary piston 5, the air pressure in the third chamber 15 is increased through the third air port 151, and the air pressure in the fourth chamber 16 is reduced through the fourth air port 161. As the air pressure difference decreases, the driving member 82 of the locking assembly 8 is affected by the elastic force of the third elastic member 83, and the driving member 82 moves into the cylinder body 1, thereby driving the locking member 81 to rotate, unlocking the locking state of the adjusting nut 72, and thereby unlocking the auxiliary piston 5.
[0057] It should be noted that a pressure relief valve is provided on the second air port 141. When the actuator moves to the intermediate state, the auxiliary piston 5, the push rod 6 and the adjusting member 7 move into place, the air pressure in the first chamber 13 increases, the main piston 4 moves toward the auxiliary piston 5, and the air pressure in the second chamber 14 increases due to its reduced volume. When the air pressure in the second chamber 14 reaches the set pressure value of the pressure limiting valve, the pressure relief valve discharges part of the gas in the second chamber 14 to ensure the air pressure difference on both sides of the main piston 4. At the same time, when the main piston 4 is about to contact the push rod 6, because some gas still remains in the second chamber 14, a certain air pressure is formed, which can reduce the moving speed of the main piston 4, form a buffer for the main piston 4, and reduce the collision of the main piston 4 with the push rod 6.
[0058] In this embodiment, when the actuator is in the fully closed state, the air pressure in the first chamber 13 is lower than that in the second chamber 14 , and the air pressures in the third chamber 15 and the fourth chamber 16 do not affect the fully closed state of the actuator.
[0059] When the actuator changes from the fully closed state to the intermediate state, the air pressure in the fourth chamber 16 increases, forming a pressure difference between the fourth chamber 16 and the third chamber 15, and the auxiliary piston 5, the push rod 6 and the adjusting member 7 move. When the auxiliary piston 5, the push rod 6 and the adjusting member 7 move into place, the locking assembly 8 locks the position of the adjusting member 7, and the damping assembly 71 forms a damping between the adjusting member 7 and the end cover 11, preventing the adjusting member 7 from moving, thereby fixing the position of the auxiliary piston 5 and the push rod 6; the air pressure in the first chamber 13 increases, and the air pressure in the second chamber 14 decreases, forming a pressure difference on both sides of the main piston 4, causing the main piston 4 to move toward the auxiliary The piston 5 moves; at the same time, the pressure difference on both sides of the main piston 4 drives the clamping part 411 in the clamping assembly 41 to move, and the clamping part 411 protrudes the main piston 4. When the main piston 4 is about to collide with the push rod 6, the clamping part 411 cushions the movement of the main piston 4 to prevent the main piston 4 and the push rod 6 from colliding; and after the main piston 4 and the push rod 6 are fully in contact, the clamping part 411 clamps the main piston 4 and the push rod 6, and the position of the main piston 4 is fixed by the clamping assembly 41, thereby ensuring the stability of the intermediate state of the actuator and preventing the valve from being affected by the fluctuation of the liquid passing through it. The valve angle is affected.
[0060] When the actuator changes from the intermediate state to the fully open state, the first chamber 13 and the second chamber 14 maintain the original air pressure, the air pressure in the third chamber 15 increases, and the air pressure in the fourth chamber 16 decreases, so that the damping assembly 71 contacts the damping state, the locking assembly 8 contacts the locking state, and the clamping assembly 41 is still in the clamping state. Since the two main pistons 4 of the clamping assembly 41 are connected to the push rod 6, and the push rod 6 is fixedly connected to the auxiliary piston 5, the main piston 4 and the auxiliary piston 5 jointly drive the transmission shaft 2 to rotate, thereby increasing the torque of the transmission shaft 2 on the valve.
[0061] When the actuator changes from the fully open state to the intermediate state, the air pressure in the first chamber 13 decreases, the second chamber 14 maintains the original air pressure, the air pressure in the third chamber 15 decreases, and the air pressure in the fourth chamber 16 increases. The air pressure difference between the third chamber 15 and the fourth chamber 16 drives the auxiliary piston 5 to move toward the main piston 4 until the auxiliary piston 5 is fixed in position by the damping assembly 71 and the locking assembly 8. The air pressure in the first chamber 13 is increased through the first air port 131, forming a pressure difference with the second chamber 14, driving the main piston 4 to move until the main piston 4 and the push rod 6 are completely engaged.
[0062] When the actuator changes from the intermediate state to the fully closed state, the air pressure in the first chamber 13 decreases, the air pressure in the second chamber 14 increases, and the pressure difference on both sides of the main piston 4 changes, causing the clamping part 411 of the clamping assembly 41 to retract into the main piston 4, and the main piston 4 and the push rod 6 are released from the clamping state, and the main piston 4 moves in the direction away from the auxiliary piston 5, completing the fully closed state of the actuator; during this process, the air pressure in the third chamber 15 and the fourth chamber 16 can remain unchanged, which is convenient for the next transition to the intermediate state; the third chamber 15 and the fourth chamber 16 can also be connected to the outside of the cylinder body 1, so that the auxiliary piston 5 can be easily moved; the air pressure in the third chamber 15 can also be increased and the air pressure in the fourth chamber 16 can be reduced, so as to move the auxiliary piston 5 in the direction away from the main piston 4, so that the auxiliary piston 5 and the push rod 6 will not affect the movement of the main piston 4.
[0063] In this embodiment, the position of the auxiliary piston 5 is fixed by the damping assembly 71 when the actuator is in the intermediate state, preventing the auxiliary piston 5 from being moved by the kinetic energy of the movement of the main piston 4; the clamping member 411 in the clamping assembly 41 can further weaken the kinetic energy when the main piston 4 contacts the push rod 6, and at the same time connect the main piston 4 with the auxiliary piston 5 to ensure the accuracy of the intermediate state of the actuator; the locking assembly 8 further fixes the position of the auxiliary piston 5 on the basis of the damping assembly 71 preventing the auxiliary piston 5 from moving. The above settings reduce the impact force of the main piston 4 on the push rod 6, improve the stability of the position of the auxiliary piston 5, and improve the accuracy and stability of the intermediate state of the actuator. At the same time, it prevents the auxiliary piston 5 from being displaced or vibrated after being hit by the main piston 4, and prevents deviations in the intermediate state of the actuator.
[0064] Example 2 In actual use, when the flow rate of the liquid passing through the valve connected to the actuator changes, the opening and closing angle of the valve will change, resulting in deviations in the calculation of the flow rate through the valve.
[0065] In order to solve the above technical problems, Figures 1 to 12 As shown, in another embodiment of the present invention: a limit block 21 is provided on the transmission shaft 2, and the limit block 21 rotates synchronously with the transmission shaft 2. The actuator also includes a limit assembly 3. The limit assembly 3 can limit and maintain the limit state of the transmission shaft 2 through the limit block 21, and release the limit on the transmission shaft 2 after the air pressure changes. The limit assembly 3 prevents the transmission shaft 2 from overtravel and realizes automatic reset under air pressure changes.
[0066] The limit assembly 3 can lock the transmission shaft 2 when the actuator is in the fully open and fully closed states, and can release the locking state when the air pressure in the cylinder 1 changes.
[0067] The limiting assembly 3 includes two limiting rods 31, each of which is provided with a fixing nut 39 connected to the cylinder body 1. A telescopic cylinder 37 is provided on the outer sleeve of the limiting rod 31, and a sliding member 38 hinged to the telescopic cylinder 37 is provided at one end of the telescopic cylinder 37 away from the fixing nut 39. A sliding groove 211 is provided on the limiting block 21, and the sliding member 38 is slidably connected to the limiting block 21 through the sliding groove 211.
[0068] A limiting member 33 is provided in the limiting rod 31, and a limiting groove 371 is provided in the telescopic cylinder 37 to cooperate with the limiting member 33. The limiting groove 371 can be an annular groove. After rotating the limiting rod 31, the limiting member 33 can still cooperate with the limiting groove 371. The limiting member 33 is slidably connected to the limiting rod 31. The limiting rod 31 is also provided with a moving member 34 sliding therein. An active cavity 32 for sliding of the limiting member 33 and the moving member 34 is opened in the limiting rod 31. The limiting member 33 contacts the side of the moving member 34. The sliding of the moving member 34 can change the contact state of the limiting member 33 and the telescopic cylinder 37. The moving member 34 can move according to the change of air pressure in the cylinder body 1.
[0069] A first elastic member 35 is provided on the outer sleeve of the limiting member 33. The first elastic member 35 ensures that the limiting member 33 always keeps in contact with the movable member 34 when it moves. One end of the first elastic member 35 is connected to the limiting member 33, and the other end is connected to the movable cavity 32 in the limiting rod 31; a second elastic member 36 is provided on the end of the movable member 34 away from the telescopic cylinder 37, and one end of the second elastic member 36 is connected to the movable member 34, and the other end is connected to the inner wall of the movable cavity 32.
[0070] The fixing nut 39 is fixedly connected to the outer surface of the cylinder body 1, and the fixing nut 39 is connected to the limit rod 31 by a threaded connection. The limit rod 31 passes through the fixing nut 39 and the cylinder body 1. One end of the limit rod 31 extends out of the cylinder body 1, and the other end is located in the first chamber 13 of the cylinder body 1. The telescopic cylinder 37 is sleeved on the end of the limit rod 31 located in the cylinder body 1. The end of the telescopic cylinder 37 away from the limit rod 31 has a bottom. The sliding member 38 is hinged to the outside of the bottom of the telescopic rod. The limit member 33 slides along the radial direction of the limit rod 31, and the moving member 34 slides along the axial direction of the limit rod 31.
[0071] The moving part 34 includes a driving part 341, a piston part 342 and a resistance part 343. The driving part 341 is provided with an inclined surface, which contacts the limiting part 33 and can drive the position state of the limiting part 33; the piston part 342 and the movable chamber 32 form a sealing structure, and the resistance part 343 can extend out of the limiting rod 31 and contact the bottom of the telescopic cylinder 37. The telescopic cylinder 37 can move the moving part 34 through the resistance part 343 to complete the locking state of the limiting assembly 3.
[0072] There are two limit rods 31, namely the first limit rod 311 and the second limit rod 312. When the actuator is in the fully closed state, the limit rod 31 that contacts the inner side of the bottom of the telescopic cylinder 37 is the first limit rod 311, and the other limit rod 31 is the second limit rod 312. The active cavity 32 in the first limit rod 311 and the moving part 34 form a sealed chamber, which is located on the side of the moving part 34 away from the telescopic cylinder 37; the active cavity 32 in the second limit rod 312 and the moving part 34 form another sealed chamber, which is located on the side of the moving part 34 close to the telescopic cylinder 37.
[0073] The movable member 34 in the first limiting rod 311 has a piston portion 342, which is located on the side of the driving member 341 away from the telescopic cylinder 37, and the other side of the driving member 341 is a resistance portion 343. The resistance portion 343 is a cylindrical structure and can be connected to the first chamber 13. The bottom of the telescopic cylinder 37 connected to the first limiting rod 311 is provided with a through hole that is connected to the internal gas of the resistance portion 343; the movable member 34 in the second limiting rod 312 has two piston portions 342, which are located on the side of the driving member 82 away from and close to the telescopic cylinder 37. The piston portion 342 close to the telescopic cylinder 37 is provided with a resistance portion 343, which is located on the side of the piston portion 342 close to the telescopic portion. The resistance portion 343, the piston portion 342 and the second limiting rod 312 together form a sealed chamber in the second limiting rod 312. The active chamber 32 in the second limiting rod 312, which is located on the side of the movable member 34 away from the telescopic cylinder 37, is connected to the first chamber 13 through the air path 17.
[0074] The moving part 34 senses the change in air pressure and pushes the limit part 33, which automatically releases the limit after disengaging from the limit groove 371, which is more efficient than mechanical reset; the hinged design of the telescopic cylinder 37 and the sliding part 38 can absorb the overload impact of the transmission shaft 2 and protect the gear structure.
[0075] When the actuator is transformed into a fully closed state, the air pressure in the first chamber 13 is low, the sealed chamber of the active chamber 32 in the first limiting rod 311 has a higher air pressure than the first chamber 13, the movable part 34 in the first limiting rod 311 moves to a position away from the fixing nut 39, the limiting part 33 is located in the limiting rod 31, and the limiting rod 31 does not extend out; at this time, the sealed chamber of the active chamber 32 in the second limiting rod 312 has a higher air pressure than the first chamber 13, the movable part 34 in the first limiting rod 311 moves to a position close to the fixing nut 39, the limiting part 33 is located in the limiting rod 31, and the limiting rod 31 does not extend out.
[0076] When the actuator is in the fully closed state, the bottom of the telescopic cylinder 37 cooperating with the first limiting rod 311 moves the movable member 34 toward the direction close to the fixing nut 39, so that the movable member 34 causes the limiting member 33 to partially protrude from the limiting rod 31 and extend into the limiting groove 371 on the telescopic cylinder 37, completing the fixation of the telescopic cylinder 37, thereby fixing the limiting block 21 and limiting the rotation of the transmission shaft 2; at this time, the second limiting rod 312 has not changed, the movable member 34 is still in a position close to the fixing nut 39, and the limiting member 33 has not extended out of the limiting rod 31.
[0077] When the actuator exits the fully closed state, the air pressure in the first chamber 13 increases and is higher than the air pressure in the sealed chamber of the active chamber 32. The movable part 34 in the first limiting rod 311 moves to a position close to the fixed nut 39, and the limiting part 33 retracts into the limiting rod 31, contacting the limiting block 21 and the locking state of the transmission shaft 2; at this time, in the second limiting rod 312, the movable part 34 moves to a position away from the fixed nut 39. During the movement, the limiting part 33 extends out of the limiting rod 31 and then quickly retracts into the limiting rod 31. At this time, the telescopic cylinder 37 cooperating with the second limiting rod 312 is located at a position away from the fixed nut 39, which will not affect the extension and retraction of the limiting part 33.
[0078] When the actuator is in the middle state, the air pressure in the first chamber 13 is relatively high, the moving part 34 in the first limiting rod 311 is located close to the fixing nut 39, and the moving part 34 in the second limiting rod 312 is located away from the fixing nut 39, and the limiting part 33 will not extend out of the limiting rod 31.
[0079] When the actuator is transformed into a fully open state, the air pressure in the first chamber 13 is relatively high, the sealed chamber of the active chamber 32 in the first limiting rod 311 has a lower air pressure than the first chamber 13, the movable part 34 in the first limiting rod 311 moves to a position close to the fixing nut 39, the limiting part 33 is located in the limiting rod 31, and the limiting rod 31 does not extend out; at this time, the sealed chamber of the active chamber 32 in the second limiting rod 312 has a lower air pressure than the first chamber 13, the movable part 34 in the first limiting rod 311 moves to a position away from the fixing nut 39, the limiting part 33 is located in the limiting rod 31, and the limiting rod 31 does not extend out.
[0080] When the actuator is in the fully open state, the bottom of the telescopic cylinder 37 cooperating with the second limiting rod 312 moves the movable member 34 toward the direction close to the fixing nut 39, so that the movable member 34 causes the limiting member 33 to partially protrude from the limiting rod 31 and extend into the limiting groove 371 on the telescopic cylinder 37, completing the fixation of the telescopic cylinder 37, thereby fixing the limiting block 21 and limiting the rotation of the transmission shaft 2; at this time, the first limiting rod 311 has not changed, the movable member 34 is still in a position close to the fixing nut 39, and the limiting member 33 has not extended out of the limiting rod 31.
[0081] When the actuator exits the fully open state, the air pressure in the first chamber 13 decreases and is lower than the air pressure in the sealed chamber of the active chamber 32. The movable part 34 in the second limiting rod 312 moves to a position close to the fixed nut 39, and the limiting part 33 retracts into the limiting rod 31, contacting the limiting block 21 and the locking state of the transmission shaft 2; at this time, in the first limiting rod 311, the movable part 34 moves to a position away from the fixed nut 39. During the movement, the limiting part 33 extends out of the limiting rod 31 and then quickly retracts into the limiting rod 31. At this time, the telescopic cylinder 37 cooperating with the first limiting rod 311 is located at a position away from the fixed nut 39, which will not affect the extension and retraction of the limiting part 33.
[0082] When the actuator is in the fully open state or the fully closed state, the telescopic cylinder 37 close to the fixing nut 39 pushes the movable part 34 to move toward the direction close to the fixing nut 39, and the limiting part 33 is moved to the limiting groove 371 through the inclined surface on the movable part 34, and the limiting of the limiting block 21 and the transmission shaft 2 is completed by the slider; when the actuator is released from the fully open state or the fully closed state, the air pressure in the first chamber 13 changes drastically, and the air pressure difference pushes the movable part 34, and the movable part 34 and the limiting part 33 are staggered. The first elastic part 35 pulls the limiting part 33 back into the limiting rod 31, releasing the limiting of the limiting block 21 and the transmission shaft 2.
[0083] The fully open state and the fully closed state of the actuator can be adjusted by adjusting the length of the limit rod 31 extending out of the cylinder body 1, thereby changing the rotation range of the transmission shaft 2.
[0084] During the operation of the actuator, when the valve connected to it needs to pass a large flow of liquid, the actuator switches to the fully open state, and the compressed air enters the first chamber 13 through the first air inlet, pushing the two main pistons 4 away from each other. The main piston 4 can complete the engagement with the push column under the action of air pressure, and the compressed air enters the third chamber 15 through the third air port 151, pushing the auxiliary pistons 5 away from each other; the main piston 4 and the auxiliary piston 5 jointly drive the transmission shaft 2 to rotate, fully open the valve, and fix the valve state through the limit assembly 3.
[0085] When the valve needs to pass a small flow of liquid, the actuator switches to the intermediate state, and the compressed air enters the fourth chamber 16 through the fourth air inlet. The auxiliary piston 5 moves into place and is fixed by the damping assembly 71 and the locking assembly 8. The compressed air enters the first chamber 13 through the first air inlet, pushing the two main pistons 4 away from each other. Under the action of air pressure, the clamping part 411 extends to alleviate the collision between the main piston 4 and the push rod 6. The clamping part 411 is embedded in the clamping groove 61 to complete the clamping of the main piston 4 and the push column, thereby achieving fixation in the intermediate state.
[0086] When the valve needs to be closed, the actuator switches to the fully closed state, and the compressed air enters the second chamber 14 through the second air inlet. Under the action of air pressure, the clamping part 411 retracts into the main piston 4, releasing the clamping connection between the main piston 4 and the push column, pushing the two main pistons 4 closer to each other until they are in the fully closed state, completely closing the valve, and fixing the valve state through the limit assembly 3.
[0087] The present invention sets a limit component 3 so that the actuator can be locked in the fully open state and the fully closed state, thereby ensuring the stability of the actuator during use, and the limit component 3 can release the locked state according to the air pressure change in the first chamber 13. The above setting can automatically lock and unlock the position of the transmission shaft 2 according to the air pressure change; it solves the problem of valve position deviation when the flow through the valve changes.
[0088] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, should be covered by the scope of protection of the present invention.
Claims
1. A three-stage pneumatic actuator, comprising a cylinder (1), a transmission shaft (2), a main piston (4) and an auxiliary piston (5), wherein the main piston (4) is capable of driving the transmission shaft (2) to rotate, a push rod (6) is provided between the main piston (4) and the auxiliary piston (5), and an adjusting member (7) is provided on the side of the auxiliary piston (5) away from the main piston (4), characterized in that: Also includes: A clamping assembly (41) is provided on the main piston (4), and the clamping assembly (41) can change the clamping state between the main piston (4) and the push rod (6) according to the air pressure difference on both sides of the main piston (4); The damping assembly (71) is arranged on the adjusting member (7) and can change the contact state between the adjusting member (7) and the cylinder (1) according to the surrounding pressure environment, thereby achieving the positioning and relaxation of the auxiliary piston (5).
2. The actuator according to claim 1, characterized in that The clamping assembly (41) comprises a clamping member (411), and a clamping cavity (412) for the clamping member (411) to move is provided in the main piston (4).
3. The actuator according to claim 2, characterized in that The push rod (6) is provided with a clamping groove (61) that cooperates with the clamping member (411), and a connecting hole (42) is further provided in the main piston (4), wherein the connecting hole (42) connects the clamping cavity (412) with a cavity on a side of the main piston (4) away from the push rod (6).
4. The actuator according to claim 1, characterized in that The damping assembly (71) includes a damping block (711), and a moving cavity (712) for the damping block (711) to move is provided in the adjusting member (7).
5. The actuator according to claim 4, characterized in that One end of the adjusting member (7) is connected to the auxiliary piston (5), and the other end extends out of the cylinder body (1). The portion of the adjusting member (7) extending out of the cylinder body (1) is sleeved with an adjusting nut (72). The damping assembly (71) further includes a ventilation channel (713). The ventilation channel (713) connects the moving cavity (712) with the cavity of the auxiliary piston (5) on the side away from the push rod (6).
6. The actuator according to claim 1, characterized in that The transmission shaft (2) is provided with a limit block (21), and the actuator further comprises a limit assembly (3). The limit assembly (3) is capable of limiting and maintaining the limit state of the transmission shaft (2) through the limit block (21), and releasing the limit on the transmission shaft (2) after the air pressure changes.
7. The actuator according to claim 6, characterized in that The limiting assembly (3) includes two limiting rods (31), each of which is provided with a fixing nut (39) connected to the cylinder body (1), and a telescopic cylinder (37) is provided on the outer sleeve of the limiting rod (31). An end of the telescopic cylinder (37) away from the fixing nut (39) is provided with a sliding member (38) hinged to the telescopic cylinder (37), and a sliding groove (211) is provided on the limiting block (21), and the sliding member (38) is slidably connected to the limiting block (21) through the sliding groove (211).
8. The actuator according to claim 7, characterized in that The limiting rod (31) is provided with a limiting member (33) and a moving member (34) which are slidably connected thereto, and the telescopic cylinder (37) is provided with a limiting groove (371) which cooperates with the limiting member (33). The sliding of the moving member (34) can change the contact state between the limiting member (33) and the telescopic cylinder (37), and the moving member (34) can move according to the change of the air pressure in the cylinder (1).
9. The actuator according to claim 1, characterized in that It also includes a locking assembly (8), which is located at the end of the cylinder body (1). Multiple groups of the locking assemblies (8) are provided around the adjusting member (7), and the locking assemblies (8) are capable of locking the position of the adjusting member (7).
10. The actuator according to claim 9, characterized in that The locking assembly (8) comprises a locking member (81) and a driving member (82) which are hinged to each other, wherein the locking member (81) is connected to the cylinder body (1), the driving member (82) passes through the cylinder body (1) and is slidably connected to the cylinder body (1), and a third elastic member (83) is provided on the outer cover of the driving member (82).