High-thrust single-action piston type pneumatic actuator

Abstract

The utility model discloses a high-thrust single-acting piston type pneumatic actuator, and relates to the field of pneumatic actuators. An existing piston type pneumatic actuator has the problems of unbalanced spring acting force, poor structural stability, insufficient sealing and the like. The hydraulic cylinder comprises a lower cylinder cover, a cylinder sleeve, a piston, a push rod, an upper cylinder cover, a lower spring seat assembly, a supporting sleeve, an upper spring seat, a lead screw, a hand wheel seat and a hand wheel transmission assembly, and is provided with multiple sealing rings. An independent spring seat structure is adopted, a bearing assembly is matched, the spring does not directly act on the piston any more, stable force transmission is ensured, the stability and reliability in a high-frequency vibration environment are effectively improved, air source leakage is effectively prevented through multiple sealing, the maintenance cost is reduced, and the performance requirement of industrial automation for a high-thrust actuator is met.

Description

Technical Field

[0001] This utility model relates to the field of pneumatic actuators, and in particular to a high-thrust single-acting piston pneumatic actuator. Background Technology

[0002] Piston pneumatic actuators, as core components of industrial automation control systems, are widely used in valve regulation, fluid control and other fields. They achieve precise control of mechanical components by driving piston movement with compressed air.

[0003] In existing piston-type pneumatic actuators, springs are mostly directly installed between the limit seat and the piston. The force of the handwheel transmission assembly is mostly driven by directly compressing the spring to move the piston. When the pressure exceeds a certain level, the force exerted by the spring on the piston is prone to imbalance. Furthermore, since the limit seat is mostly directly installed on the push rod, there is usually no structure above the limit seat for stable support. Under high-frequency operation or vibration environment during long-term operation, the limit seat is also prone to uneven stress, making the structure unstable and relatively easy to loosen. This results in low stability and reliability, and also imposes significant limitations on the operation of the pneumatic actuator when increasing the thrust. Utility Model Content

[0004] The technical problem to be solved and the technical task proposed by this utility model is to improve and refine the existing technical solutions, and to provide a high-thrust single-acting piston pneumatic actuator, with the aim of improving the reliability and stability of the high-thrust pneumatic actuator during operation. To this end, this utility model adopts the following technical solution.

[0005] A high-thrust single-acting piston pneumatic actuator includes a lower cylinder head, a cylinder liner, a piston, a push rod, an upper cylinder head, a lower spring seat assembly, a support sleeve, an upper spring seat, a lead screw, a handwheel seat, and a handwheel transmission assembly. The cylinder liner is connected and fixed between the lower and upper cylinder heads. The support sleeve is disposed on the upper cylinder head. The lower outer periphery of the upper spring seat is connected and fixed to the upper end of the support sleeve. The piston is disposed in the inner cavity of the cylinder liner. The push rod passes through the center hole of the piston from bottom to top. The lower end of the lower spring seat assembly is connected and fixed to the push rod through a bearing assembly. The lower end of the bearing assembly is in contact with the upper end face of the piston. The upper end of the push rod passes through the center hole of the bearing assembly and is fastened by a locking assembly. The upper cylinder head has a through hole in the middle, connecting the inner cavity of the cylinder liner and the inner cavity of the support sleeve. The diameter of the through hole is larger than the outer diameter of the lower spring seat assembly. The upper spring seat and the lower spring... A large spring and a small spring are arranged between the seat assemblies. The large spring is sleeved on the outside of the small spring. There are gaps between the outer diameter of the large spring and the inner diameter of the support sleeve, and between the large spring and the small spring, to allow for spring compression. The handwheel seat is connected and fixed to the upper spring seat. The handwheel transmission assembly is connected and fixed to the upper handwheel seat. The lower middle end of the upper spring seat is connected and fixed to a limit seat. The upper end of the lead screw is connected to the handwheel transmission assembly. The lead screw passes downward through the handwheel seat and then passes through the center hole of the upper spring seat and the center hole of the limit seat in sequence. The lower spring seat assembly has an inner cavity. The lower end of the lead screw slidably passes through the upper end of the lower spring seat assembly and enters the inner cavity of the lower spring seat assembly. The lower end of the lead screw is connected to the limit assembly so that when the lead screw retracts upward, it drives the lower spring seat assembly to move upward, thereby driving the piston and push rod assembly to move upward within the cylinder liner. The independent spring seat structure changes the traditional method of directly mounting the spring between the limit seat and the piston. This structure prevents the spring from acting directly on the piston. Instead, the spring's compression force acts on the lower spring seat assembly. Combined with the internal and external arrangement of the small and large springs and the bearing assembly, the force transmission is more stable and reliable. This effectively avoids the imbalance of the spring's force on the piston when the pressure exceeds a certain level. At the same time, the limit seat is fixed to the upper spring seat, which is stably supported by the support sleeve. Compared with the traditional structure where the limit seat is directly mounted on the push rod without stable support above, this significantly improves the stability of the structure under high-frequency operation or vibration environment, reduces the risk of loosening, lowers the working limitations of the pneumatic actuator when increasing thrust, and improves stability and reliability.

[0006] As a preferred technical means: the lower spring seat assembly includes a lower spring seat, a limiting sleeve, a lower spring seat end cap, and a spring pad. The limiting sleeve is disposed on the upper middle part of the lower spring seat. The spring pad is connected and fixed to the upper end of the limiting sleeve. The lower spring seat end cap is connected and fixed to the upper part of the spring pad, and the middle part of the lower spring seat end cap extends downward and is embedded in the central hole of the spring pad. The lower end of the lead screw passes through the central hole of the lower spring seat end cap. The limiting assembly includes a first one-way thrust ball bearing and a bearing positioning screw. The outer diameter of the first one-way thrust ball bearing is larger than the inner diameter of the central hole of the lower spring seat end cap by 25%-35%. The first one-way thrust ball bearing is connected and fixed to the lower end of the lead screw by the bearing positioning screw. The lower spring seat assembly structure facilitates the installation and lateral positioning of the spring, and provides a movable internal cavity environment for the lead screw and the first one-way thrust ball bearing. The outer diameter of the first one-way thrust ball bearing at the lower end of the lead screw is 25%-35% larger than the inner diameter of the center hole of the lower spring seat end cover. This dimension can effectively increase the force-bearing area and accurately and stably bear the one-way axial force generated by the lead screw during operation. This bearing can ensure the accuracy of force transmission and the balance of force distribution between the lead screw and the lower spring seat assembly, and strongly guarantee the structural stability.

[0007] As a preferred technical means, the bearing assembly includes a bearing housing, a second one-way thrust ball bearing, and a deep groove ball bearing. The bearing housing has two annular bearing steps. The second one-way thrust ball bearing is located on the first bearing step from bottom to top, and the deep groove ball bearing is located on the second bearing step from bottom to top. The lower spring seat has a stepped hole in the middle, which mates with the bearing assembly. The stepped hole of the lower spring seat has an interference fit with the outer ring of the deep groove ball bearing, and an interference fit with the upper ring of the second one-way thrust ball bearing. There is a clearance between the stepped hole of the lower spring seat and the rest of the bearing assembly. This structure can effectively withstand loads in different directions. The second one-way thrust ball bearing bears axial force, and the deep groove ball bearing bears radial force. This allows the lower spring seat assembly to be subjected to more balanced forces during operation, reducing wear and loosening caused by uneven force distribution, and improving the service life and operational stability of the entire actuator.

[0008] As a preferred technical approach: the upper spring seat is provided with an annular spring groove, in which the upper ends of the large and small springs are located; the lower spring seat is provided with an annular rib, in which the lower end of the small spring is located in the annular small spring groove inside the annular rib, and the lower end of the large spring is located outside the annular rib. This structure provides precise installation and positioning for the large and small springs, ensuring that the springs do not shift or misalign during compression and extension, making the spring force more stable and uniform, thereby further improving the stability and reliability of the actuator during operation, and ensuring smoother and more precise movement of the piston and push rod.

[0009] As a preferred technical means: a lower guide sleeve is provided in the center hole of the lower cylinder head, and the push rod passes through the center guide hole of the lower guide sleeve and slides in engagement with the lower guide sleeve; an upper guide sleeve is provided in the lower middle part of the limiting seat, and the smooth part of the lead screw passes through the center guide hole of the upper guide sleeve and slides in engagement with the upper guide sleeve. The lower and upper guide sleeves provide precise guidance for the push rod and the lead screw, respectively, reducing friction and wobble between the push rod and the center hole of the lower cylinder head, and between the lead screw and the center hole of the limiting seat, ensuring the linearity and accuracy of the push rod and the lead screw movement, improving the control precision of the actuator, and reducing component wear and extending service life.

[0010] As a preferred technical means: an upper O-ring is provided between the upper end of the cylinder liner and the upper cylinder head, and a lower O-ring is provided between the lower end of the cylinder liner and the lower cylinder head; multiple inner O-rings are provided between the inner circumference of the lower guide sleeve and the push rod, and multiple outer O-rings are provided between the outer circumference of the lower guide sleeve and the lower cylinder head; multiple inner O-rings are provided between the push rod and the piston; an oil seal is provided at the lower end of the lower guide sleeve, and an end cap is provided below the oil seal, which is fixed to the bottom of the lower cylinder head; an upper spring seat O-ring is provided between the bottom surface of the handwheel seat and the upper spring seat. Multiple O-rings and oil seals are provided between the cylinder liner and the upper and lower cylinder heads, as well as at the mating points of various components, forming a multi-seal structure. This effectively solves the problem of insufficient sealing performance in traditional actuators, prevents gas leakage in high-pressure, high-temperature, or corrosive media environments, improves the stability and safety of actuator operation, and reduces problems such as decreased power transmission efficiency due to leakage.

[0011] As a preferred technical approach, the piston has two guide bands on its outer circumference, with an O-ring seal between them. The piston then mates with the cylinder liner's inner diameter via the guide bands and the O-ring seal. This provides excellent guidance for the piston's movement within the cylinder liner, ensuring smooth operation and reducing frictional resistance. It also enhances the sealing performance between the piston and cylinder liner, preventing gas leakage and ensuring the stability and high efficiency of the actuator.

[0012] As a preferred technical approach, the upper and lower cylinder heads are connected and secured by multiple sets of fastening components. These fastening components are evenly distributed around the outer side of the cylinder liner. Each set includes a fully threaded stud, a corresponding washer, and a nut. At least one-third of the fastening components contain unloading long nuts, which are evenly distributed around the center of the cylinder liner. While ensuring the secure connection between the upper and lower cylinder heads and the cylinder liner, the unloading long nuts, with their anti-loosening, vibration-damping, load-distributing, and easy-to-disassemble / maintain characteristics, further enhance the vibration resistance of the overall actuator structure, reduce connection loosening caused by vibration, lower maintenance difficulty and cost, and improve the reliability of equipment operation.

[0013] As a preferred technical approach: Multiple vertical vent holes are evenly distributed around the upper and lower cylinder heads. These vent holes are radially located inside the cylinder liner and outside the support sleeve. The vent holes on the upper cylinder head are fitted with rain caps, each containing a small, penetrating vent. The presence of vent holes on the upper and lower cylinder heads, with rain caps on the upper cylinder head vent holes, ensures airflow within the actuator while preventing rainwater and other external debris from entering. This avoids issues such as component wear and seal failure caused by debris, protects the actuator's internal structure, extends its service life, and improves operational stability.

[0014] As a preferred technical approach, the upper cylinder head is evenly distributed with multiple lifting rings, which are located on the outside of the cylinder liner. The evenly distributed lifting rings around the upper cylinder head facilitate the lifting, transportation, and installation of the actuator. Compared to traditional actuators, which may suffer from inconvenient operation and easily damaged parts due to a lack of convenient lifting structures during handling, this significantly improves operational convenience and safety, and reduces the labor intensity and risks during installation and handling.

[0015] Beneficial effects:

[0016] 1. The independent spring seat structure changes the traditional method of directly mounting the spring between the limit seat and the piston. This structure prevents the spring from acting directly on the piston. The spring's compression force acts on the lower spring seat assembly. Combined with the internal and external arrangement of the small and large springs, and through the bearing assembly, the force transmission is more stable and reliable. This effectively avoids the imbalance of the spring's force on the piston when the pressure exceeds a certain level. At the same time, the limit seat is fixed to the upper spring seat, which is stably supported by the support sleeve. Compared with the traditional structure where the limit seat is directly mounted on the push rod without stable support above, this significantly improves the stability of the structure under high-frequency operation or vibration environment, reduces the risk of loosening, lowers the working limitations of the pneumatic actuator when increasing thrust, and improves stability and reliability.

[0017] 2. Multiple O-rings and oil seals are installed between the cylinder liner and the upper and lower cylinder heads, as well as at the mating points of various components, forming a multi-layer sealing structure. This effectively solves the problem of insufficient sealing performance of traditional actuators, prevents gas leakage in high-pressure, high-temperature, or corrosive media environments, improves the stability and safety of actuator operation, and reduces problems such as decreased power transmission efficiency caused by leakage.

[0018] 3. The pneumatic actuator is easy to install and maintain by using fully threaded studs, unloading long nuts and lifting rings, which allows the actuator to be quickly assembled or parts replaced, greatly reducing maintenance difficulty and time costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] Figure 2 This is a schematic diagram of a partial radial section of the structure of this utility model.

[0021] Figure 3 This is a utility model Figure 2 Enlarged schematic diagram of section A in the middle.

[0022] Figure 4 This is a utility model Figure 2 Enlarged schematic diagram of section B in the middle.

[0023] Figure 5 This is a utility model Figure 2 Enlarged schematic diagram of section C.

[0024] Figure 6 This is a utility model Figure 2 Enlarged schematic diagram of section D in the middle.

[0025] Figure 7 This is a utility model Figure 2 Enlarged schematic diagram of section E in the middle.

[0026] In the diagram: 1. Lower cylinder head; 2. Cylinder liner; 3. Piston; 4. Push rod; 5. Upper cylinder head; 6. Support sleeve; 7. Upper spring seat; 8. Lead screw; 9. Handwheel seat; 10. Lower spring seat; 11. Limit sleeve; 12. Lower spring seat end cap; 13. Spring washer; 14. Double-layered self-locking washer; 15. Locking nut; 16. Large spring; 17. Small spring; 18. Limit seat; 19. Bevel tooth handwheel; 20. Rotary handwheel; 21. Anti-rotation nut; 22. Cotter pin; 23. First one-way thrust ball bearing; 24. Bearing locating screw; 25. Heavy-duty elastic cylindrical pin; 26. Bearing seat; 27. Second one-way thrust ball bearing; 28. Deep groove ball bearing; 29. ​​Lower guide sleeve; 30. Upper guide sleeve. 31. Elastic retaining ring for bore; 32. Upper O-ring seal for cylinder liner; 33. Lower O-ring seal for cylinder liner; 34. Inner circumferential O-ring seal for lower guide sleeve; 35. Outer circumferential O-ring seal for lower guide sleeve; 36. Inner bore O-ring seal for piston; 37. Oil seal seal; 38. End cap; 39. Upper spring seat O-ring seal; 40. Guide band; 41. Outer circumferential O-ring seal for piston; 42. Rain cap; 43. Equal length double-ended bolt fastening assembly; 44. Fully threaded stud fastening assembly; 45. Lifting eye; 501. Upper cylinder head through hole; 701. Annular spring groove; 801. Threaded part; 802. Stepped shaft part; 803. Polished rod part; 1001. Annular rib plate; 1002. Annular small spring groove. Detailed Implementation

[0027] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings.

[0028] Example 1

[0029] like Figures 1-3 and Figure 6 , Figure 7As shown, a high-thrust single-acting piston-type pneumatic actuator includes a lower cylinder head 1, a cylinder liner 2, a piston 3, a push rod 4, an upper cylinder head 5, a lower spring seat 10 assembly, a support sleeve 6, an upper spring seat 7, a lead screw 8, a handwheel seat 9, and a handwheel transmission assembly. The cylinder liner 2 is connected and fixed between the lower cylinder head 1 and the upper cylinder head 5. The support sleeve 6 is located on the upper cylinder head 5. The lower outer periphery of the upper spring seat 7 is embedded in the inner side of the upper end of the support sleeve 6, and the outer periphery of the upper spring seat 7 and the upper end of the support sleeve 6 are fixed by circumferential welding. The lower middle end of the upper spring seat 7 is connected and fixed with a limit seat 18. The piston 3 is located inside the cylinder liner 2. The push rod 4 passes through the center hole of the piston 3 from bottom to top. The lower spring seat 10 assembly includes a lower spring seat 10, a limiting sleeve 11, a lower spring seat end cap 12, and a spring pad 13. The limiting sleeve 11 is located on the upper middle part of the lower spring seat 10. The spring pad 13 is connected and fixed to the upper end of the limiting sleeve 11. The lower spring seat end cap 12 is connected and fixed to the upper part of the spring pad 13, and the middle part of the lower spring seat end cap 12 extends downward and is embedded in the center hole of the spring pad 13. The lower spring seat 10 is connected and fixed to the push rod 4 through a bearing assembly. The lower end of the bearing assembly is in contact with the upper end face of the piston 3. The upper end of the push rod 4 passes through the center hole of the bearing assembly and is fastened by a locking assembly including a double-layered self-locking washer 14 and a locking nut 15. The upper cylinder head 5 has a through hole 501 in the middle, connecting the inner cavity of the cylinder sleeve 2 and the inner cavity of the support sleeve 6. The diameter of the through hole 501 is larger than the outer diameter of the lower spring seat 10, and the diameter of the through hole 501 is the same as the inner diameter of the support sleeve 6. A large spring 16 and a small spring 17 are arranged between the upper spring seat 7 and the lower spring seat 10. The outer diameter of the large spring 16 is smaller than the outer diameter of the lower spring seat 10. The large spring 16 is fitted outside the small spring 17, and the small spring 17 is fitted outside the limiting sleeve 11 and the limiting seat 18. There are gaps between the outer diameter of the large spring 16 and the inner diameter of the support sleeve 6, and between the large spring 16 and the small spring 17, to allow for spring compression. The upper cylinder head 5 and the lower cylinder head 1 are connected and fastened by twelve sets of fastening components, which are evenly distributed around the outer side of the cylinder sleeve 2. The handwheel seat 9 is fixed to the upper spring seat 7 by a ring of evenly distributed hexagonal head screws. The handwheel drive assembly includes a bevel handwheel 19 and a rotary handwheel 20. The housing of the bevel handwheel 19 is fixed to the upper part of the handwheel seat 9 by hexagonal head bolts. The upper end of the lead screw 8 is threaded to connect to the bevel handwheel 19. The right side of the bevel handwheel 19 is connected to the rotary handwheel 20. By operating the rotary handwheel 20, the lead screw 8 is driven to move via the bevel handwheel 19. The lead screw 8 passes downward through the handwheel seat 9 and then sequentially through the center hole of the upper spring seat 7 and the center hole of the limit seat 18. The lead screw 8 includes a lead section 801 at the top, a smooth section 803 at the middle and lower part, and a stepped shaft section 802 between the lead section 801 and the smooth section 803. The stepped shaft section 802 is located inside the handwheel seat 9 and is provided with an anti-rotation nut 21, which is fixed by a cotter pin 22.The limiting assembly includes a first one-way thrust ball bearing 23 and a bearing positioning screw 24. After the lower end of the lead screw 8 passes through the center hole of the lower spring seat end cover 12, the first one-way thrust ball bearing 23 is connected and fixed to the lower end of the lead screw 8 by the bearing positioning screw 24. The bearing positioning screw 24 and the lead screw 8 are fixedly connected by a heavy-duty elastic cylindrical pin 25 and a threaded connection. The outer diameter of the first one-way thrust ball bearing 23 is 30% larger than the inner diameter of the center hole of the lower spring seat end cover 12. The first one-way thrust ball bearing 23 and the bearing positioning screw 24 are located in the inner cavity of the limiting sleeve 11. There is a gap between the lead screw 8 and the center hole of the lower spring seat end cover 12, which allows the lead screw 8 to move up and down. When the lead screw 8 retracts upward, it drives the lower spring seat 10 assembly to move upward through the limiting assembly, thereby driving the piston 3 and push rod 4 assembly to move upward.

[0030] like Figure 3 As shown, in order to withstand loads in different directions and make the lower spring seat 10 more evenly stressed during operation, the bearing assembly includes a bearing housing 26, a second one-way thrust ball bearing 27, and a deep groove ball bearing 28. The bearing housing 26 has two annular bearing steps. The second one-way thrust ball bearing 27 is located on the first bearing step from bottom to top, and the deep groove ball bearing 28 is located on the second bearing step from bottom to top. The lower spring seat 10 has a stepped hole in the middle, which is used to mate with the bearing assembly. The stepped hole of the lower spring seat 10 is interference-fitted with the outer ring of the deep groove ball bearing 28, and the stepped hole of the lower spring seat 10 is interference-fitted with the upper ring of the second one-way thrust ball bearing 27. The stepped hole of the lower spring seat 10 has clearances with the rest of the bearing assembly. This structure can effectively withstand loads in different directions. The second unidirectional thrust ball bearing 27 bears the axial force, and the deep groove ball bearing 28 bears the radial force, which enables the lower spring seat 10 assembly to be subjected to more balanced forces during operation, reducing wear and loosening caused by uneven force, and improving the service life and operational stability of the entire actuator.

[0031] To ensure precise installation positioning of the large spring 16 and the small spring 17, such as Figure 2 , 3 As shown, the upper spring seat 7 is provided with an annular spring groove 701, in which the upper ends of the large spring 16 and the small spring 17 are located. The lower spring seat 10 is provided with an annular rib plate 1001, in which the lower end of the small spring 17 is located in the annular small spring groove 1002 inside the annular rib plate 1001, and the lower end of the large spring 16 is located outside the annular rib plate 1001. This structure provides precise installation positioning for the large spring 16 and the small spring 17, ensuring that the springs will not shift or misalign during compression and extension, making the spring force more stable and uniform, thereby further improving the stability and reliability of the actuator during operation, and ensuring that the piston 3 and the push rod 4 move more smoothly and accurately.

[0032] To provide precise guidance for push rod 4 and lead screw 8, such as Figure 3 , 4 As shown, a lower guide sleeve 29 is provided in the center hole of the lower cylinder head 1. The push rod 4 passes through the center guide hole of the lower guide sleeve 29 and slides in engagement with the lower guide sleeve 29. An upper guide sleeve 30 is provided in the middle of the lower part of the limiting seat 18. An elastic retaining ring 31 for the hole is provided at the position of the limiting seat 18 at the lower end of the upper guide sleeve 30. The smooth rod part 803 of the lead screw 8 passes through the center guide hole of the upper guide sleeve 30 and slides in engagement with the upper guide sleeve 30. The lower guide sleeve 29 and the upper guide sleeve 30 provide precise guidance for the push rod 4 and the lead screw 8, respectively, reducing friction and wobble between the push rod 4 and the center hole of the lower cylinder head 1, and between the lead screw 8 and the center hole of the limiting seat 18. This ensures the linearity and accuracy of the movement of the push rod 4 and the lead screw 8, improves the control accuracy of the actuator, and at the same time reduces component wear and extends service life.

[0033] To improve the sealing effect, such as Figure 3 , Figure 5 , Figure 6 As shown, an upper O-ring 32 is provided between the upper end of cylinder liner 2 and the upper cylinder head 5, and the upper O-ring 32 is located in the sealing groove on the upper end face of cylinder liner 2. A lower O-ring 33 is provided between the lower end of cylinder liner 2 and the lower cylinder head 1, and the lower O-ring 33 is located in the sealing groove on the lower end face of cylinder liner 2. Two lower guide sleeve inner circumference O-rings 34 are provided between the inner circumference of the lower guide sleeve 29 and the push rod 4, and the two lower guide sleeve inner circumference O-rings 34 are located in two sealing grooves on the inner circumference of the lower guide sleeve 29. Two lower guide sleeve outer circumference O-rings 35 are provided between the outer circumference of the lower guide sleeve 29 and the lower cylinder head 1. The guide sleeve outer circumference O-ring 35 is provided in two sealing ring grooves on the outer circumference of the lower guide sleeve 29. Three piston inner hole O-rings 36 are provided between the push rod 4 and the piston 3. The three piston inner hole O-rings 36 are provided in three sealing ring grooves in the inner hole of the piston 3. The lower end of the lower guide sleeve 29 is provided with an oil seal 37. An end cover 38 is provided below the oil seal 37. The end cover 38 is connected and fixed to the bottom of the lower cylinder head 1 by four evenly distributed hexagonal head screws. An upper spring seat O-ring 39 is provided between the bottom surface of the handwheel seat 9 and the upper spring seat 7. The upper spring seat O-ring 39 is provided in the sealing ring groove on the upper end face of the upper spring seat 7. O-rings and oil seals 37 are installed between cylinder liner 2 and upper and lower cylinder heads 1, as well as at the mating points of various components, forming a multi-seal structure. This effectively solves the problem of insufficient sealing performance of traditional actuators, prevents gas leakage in high-pressure, high-temperature or corrosive media environments, improves the stability and safety of actuator operation, and reduces problems such as decreased power transmission efficiency caused by leakage.

[0034] To achieve good piston 3 movement, such as Figure 5As shown, the piston 3 has two guide bands 40 on its outer circumferential surface, and an outer O-ring seal 41 is provided between the two guide bands 40. The piston 3 is matched with the inner diameter of the cylinder liner 2 through the guide bands 40 and the outer O-ring seal 41. This provides good guidance for the movement of the piston 3 within the cylinder liner 2, ensuring smooth piston movement, reducing frictional resistance, and enhancing the sealing performance between the piston 3 and the cylinder liner 2 to prevent gas leakage and ensure the stability and high efficiency of the actuator.

[0035] To ensure proper gas flow within the actuator, both the upper cylinder head 5 and the lower cylinder head 1 have two vertical vent holes arranged radially symmetrically. These vent holes are located radially inside the cylinder liner 2 and outside the support sleeve 6. The vent holes on the upper cylinder head 5 are fitted with rain caps 42, each containing a small, through-hole. The presence of vent holes on both the upper and lower cylinder heads, with the rain caps 42 on the upper cylinder head 5, ensures proper gas flow within the actuator while preventing rainwater and other external debris from entering. This avoids issues such as component wear and seal failure caused by debris, protects the internal structure of the actuator, extends its service life, and improves operational stability.

[0036] During operation, rotating the handwheel 20 drives the bevel gear handwheel 19, which in turn drives the lead screw 8. When the lead screw 8 moves upward, its lower end causes the lower spring seat 10 to gradually move upward, and the piston 3 and push rod 4 move upward, allowing air to flow in through the vent hole of the lower cylinder head 1. When the lead screw 8 moves downward, the elastic force of the large spring 16 and the small spring 17 pushes the lower spring seat 10 downward, causing the piston 3 and push rod 4 to move downward, and allowing air to flow in through the vent hole of the rain cap 42.

[0037] This actuator structure, through its independent spring seat structure, changes the traditional method of directly mounting the spring between the limit seat 18 and the piston 3. This structure prevents the spring from directly acting on the piston 3; instead, the spring's compression force acts on the lower spring seat 10 assembly, and the force transmission is smoother and more reliable through the bearing assembly. This effectively avoids the imbalance of the spring's force on the piston 3 when the pressure exceeds a certain level. Simultaneously, the limit seat 18 is fixed to the upper spring seat 7, which is stably supported by the support sleeve 6. Compared to the traditional structure where the limit seat 18 is directly mounted on the push rod 4 without stable support above, this significantly improves the structure's stability under high-frequency operation or vibration environments, reduces the risk of loosening, lowers the operational limitations of the pneumatic actuator when increasing thrust, and enhances stability and reliability. Furthermore, the multi-seal structure effectively improves sealing performance, preventing air leakage in high-pressure, high-temperature, or corrosive media environments, thus improving the actuator's operational stability and safety.

[0038] Example 2

[0039] Unlike the above embodiment, as Figure 1As shown, the fastening assembly includes equal-length double-ended stud fastening assemblies 43 and fully threaded stud fastening assemblies 44. There are eight sets of equal-length double-ended stud fastening assemblies 43. Each set includes equal-length double-ended studs, flat washers, and type II hexagonal nuts. The two ends of the equal-length double-ended studs are connected to the lower cylinder head 1 and the upper cylinder head 5, respectively. The upper cylinder head 5 is secured at one end with a flat washer and a type II hexagonal nut, and the lower cylinder head 1 is similarly secured at one end with a flat washer and a type II hexagonal nut. There are four sets of fully threaded stud fastening assemblies 44, spaced two sets apart from each set of equal-length double-ended stud fastening assemblies 43. Each fully threaded stud fastening assemblies 44 include fully threaded studs and unloading long nuts. Before installing the unloading long nuts, the washers for the unloading long nuts must be installed to prevent loosening caused by mechanical vibration. The other end of the fully threaded stud is fitted with a flat washer, a type II hexagonal nut, and a hexagonal thin nut. The equal-length double-ended bolt fastening assembly 43, combined with the fully threaded stud fastening assembly 44, ensures the tight connection of the upper cylinder head 5, lower cylinder head 1 and cylinder liner 2. At the same time, it utilizes the characteristics of unloading long nuts to prevent loosening and reduce vibration, distribute load and facilitate disassembly and maintenance, further improving the vibration resistance of the overall structure of the actuator, reducing connection loosening caused by vibration, reducing maintenance difficulty and cost, and improving the reliability of equipment operation.

[0040] Example 3

[0041] Unlike Embodiment 1 or 2 above, as Figure 1 , Figure 2 As shown, three lifting rings 45 are evenly distributed around the upper cylinder head 5, and the lifting rings 45 are located on the outside of the cylinder liner 2. The evenly distributed lifting rings 45 around the upper cylinder head 5 facilitate the lifting, transportation and installation of the actuator. Compared with traditional actuators, which may have problems such as inconvenient operation and easy damage to parts due to the lack of convenient lifting structure during transportation, this greatly improves the convenience and safety of operation, and reduces the labor intensity and risks during installation and transportation.

[0042] The above-described high-thrust single-acting piston pneumatic actuator is a specific embodiment of this utility model, demonstrating its substantial features and advancements. Based on actual usage needs, equivalent modifications in shape, structure, etc., can be made to it under the guidance of this utility model, all of which are within the scope of protection of this solution.

Claims

1. A large thrust single acting piston pneumatic actuator characterized by: The application relates to a handwheel transmission assembly for a hydraulic cylinder, which comprises a lower cylinder cover, a cylinder sleeve, a piston, a push rod, an upper cylinder cover, a lower spring seat assembly, a supporting sleeve, an upper spring seat, a screw rod, a handwheel seat and a handwheel transmission assembly, the cylinder sleeve is fixedly connected between the lower cylinder cover and the upper cylinder cover, the supporting sleeve is arranged on the upper surface of the upper cylinder cover, the lower end of the outer periphery of the upper spring seat is fixedly connected to the upper end of the supporting sleeve, the piston is arranged in the inner cavity of the cylinder sleeve, the push rod passes through the central hole of the piston from bottom to top, the lower end of the lower spring seat assembly is fixedly connected to the push rod through a bearing assembly, the lower end of the bearing assembly is attached to the upper end surface of the piston, and the upper end of the push rod passes through the central hole of the bearing assembly and is fastened through a locking assembly; the middle of the upper cylinder cover is provided with an upper cylinder cover perforation which is connected with the inner cavity of the cylinder sleeve and the inner cavity of the supporting sleeve, the hole diameter of the upper cylinder cover perforation is larger than the outer diameter of the lower spring seat assembly, a large spring and a small spring are arranged between the upper spring seat and the lower spring seat assembly, the large spring is sleeved on the outer side of the small spring, and gaps are arranged between the outer diameter of the large spring and the inner diameter of the supporting sleeve and between the large spring and the small spring so that the springs can be compressed, the handwheel seat is fixedly connected to the upper surface of the upper spring seat, the handwheel transmission assembly is fixedly connected to the upper surface of the handwheel seat, the middle lower end of the upper spring seat is fixedly connected to a limiting seat, the upper end of the screw rod is in transmission connection with the handwheel transmission assembly, the screw rod passes through the central holes of the upper spring seat and the limiting seat in sequence after passing through the handwheel seat downwards, the lower spring seat assembly is provided with an inner cavity, the lower end of the screw rod can slide through the upper end of the lower spring seat assembly and enter the inner cavity of the lower spring seat assembly, and the lower end of the screw rod is connected to a limiting assembly so that when the screw rod is retracted upwards, the lower spring seat assembly is driven to move upwards, and then the combination of the piston and the push rod is driven to move upwards in the cylinder sleeve.

2. A large thrust single acting piston pneumatic actuator according to claim 1, characterized in that: The lower spring seat assembly comprises a lower spring seat, a limiting sleeve, a lower spring seat end cover and an elastic pad, the limiting sleeve is arranged on the middle upper surface of the lower spring seat, the elastic pad is fixedly connected to the upper end of the limiting sleeve, the lower spring seat end cover is fixedly connected to the upper surface of the elastic pad, the middle part of the lower spring seat end cover extends downwards and is embedded in the central hole of the elastic pad, the lower end of the screw rod passes through the central hole of the lower spring seat end cover, and the limiting assembly comprises a first one-way thrust ball bearing and a bearing positioning screw, the outer diameter of the first one-way thrust ball bearing is 25%-35% larger than the inner diameter of the central hole of the lower spring seat end cover, and the first one-way thrust ball bearing is fixedly connected to the lower end of the screw rod through the bearing positioning screw.

3. A large thrust single acting piston pneumatic actuator according to claim 2, characterized in that: The bearing assembly comprises a bearing seat, a second one-way thrust ball bearing and a deep groove ball bearing, the bearing seat is provided with two annular bearing steps, the second one-way thrust ball bearing is arranged on the first bearing step from bottom to top, and the deep groove ball bearing is arranged on the second bearing step from bottom to top, the middle of the lower spring seat is provided with a stepped hole matched with the bearing assembly, wherein the stepped hole of the lower spring seat is in interference fit with the outer ring of the deep groove ball bearing, the stepped hole of the lower spring seat is in interference fit with the upper ring of the second one-way thrust ball bearing, and the stepped hole of the lower spring seat is provided with gaps from the bearing assembly.

4. A large thrust single acting piston pneumatic actuator according to claim 3, characterized in that: The upper spring seat is provided with an annular spring groove, the upper ends of the large spring and the small spring are located in the annular spring groove, the lower spring seat is provided with an annular rib plate, the lower end of the small spring is located in an annular small spring groove on the inner side of the annular rib plate, and the lower end of the large spring is located on the outer side of the annular rib plate.

5. A large thrust single acting piston pneumatic actuator according to claim 1, characterized in that: The central hole of the lower cylinder cover is provided with a lower guide sleeve, the push rod passes through the central guide hole of the lower guide sleeve and is in sliding fit with the lower guide sleeve, and the middle of the lower part of the limiting seat is provided with an upper guide sleeve, the light rod part of the lead screw passes through the central guide hole of the upper guide sleeve and is in sliding fit with the upper guide sleeve.

6. A large thrust single acting piston pneumatic actuator according to claim 5, characterized in that: The upper end of the cylinder sleeve and the upper cylinder cover are provided with an upper O-shaped sealing ring of the cylinder sleeve, the lower end of the cylinder sleeve and the lower cylinder cover are provided with a lower O-shaped sealing ring of the cylinder sleeve, the inner periphery of the lower guide sleeve and the push rod are provided with a plurality of O-shaped sealing rings of the inner periphery of the lower guide sleeve, the outer periphery of the lower guide sleeve and the lower cylinder cover are provided with a plurality of O-shaped sealing rings of the outer periphery of the lower guide sleeve, the push rod and the piston are provided with a plurality of O-shaped sealing rings of the inner hole of the piston, the lower end of the lower guide sleeve is provided with an oil seal sealing ring, the lower part of the oil seal sealing ring is provided with an end cover, and the end cover is connected and fixed to the bottom of the lower cylinder cover.

7. A large thrust single acting piston pneumatic actuator according to claim 1, characterized in that: The outer periphery of the piston is provided with two guide belts, and the two guide belts are provided with an O-shaped sealing ring of the outer periphery of the piston, and the piston is matched with the inner diameter of the cylinder sleeve through the guide belt and the O-shaped sealing ring of the outer periphery of the piston.

8. A large thrust single acting piston pneumatic actuator according to claim 1, characterized in that: The upper cylinder cover and the lower cylinder cover are connected and fastened through a plurality of fastening assemblies, the fastening assemblies are uniformly distributed on the outer side of the cylinder sleeve, each set of fastening assembly comprises a full-thread stud, a corresponding gasket and a nut, at least 1 / 3 of the fastening assemblies contain unloading long nuts, and the unloading long nuts are uniformly distributed around the center of the cylinder sleeve.

9. A large thrust single acting piston pneumatic actuator according to claim 8, characterized in that: A plurality of vertical air holes are uniformly distributed on the upper cylinder cover and the lower cylinder cover, the air holes are located on the inner side of the cylinder sleeve in the radial direction and on the outer side of the supporting sleeve, and the air holes on the upper cylinder cover are provided with rainproof caps, and the rainproof caps are provided with air holes penetrating in and out.

10. A large thrust single acting piston pneumatic actuator according to claim 9, characterized in that: A plurality of lifting rings are uniformly distributed on the upper cylinder cover, and the lifting rings are located on the outer side of the cylinder sleeve.

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