CN113883319B

CN113883319B - Manual-automatic integrated pneumatic actuator capable of being automatically switched

Info

Publication number: CN113883319B
Application number: CN202111254768.8A
Authority: CN
Inventors: 姚鸿云; 苗壮
Original assignee: Dalian Harmo Synergy Automation Co ltd
Current assignee: Dalian Harmo Synergy Automation Co ltd
Priority date: 2021-10-27
Filing date: 2021-10-27
Publication date: 2023-08-25
Anticipated expiration: 2041-10-27
Also published as: CN113883319A

Abstract

The application provides a manual-automatic integrated pneumatic actuator, wherein a lower flange of a lower bracket is fixedly connected with an upper valve cover through a bolt, the upper flange is fixedly connected with a lower end cover, a valve rod connector is an open type threaded connector, stepped counter bores are formed in the lower end cover and the upper end cover, the lower end cover and the upper end cover are connected through pull rods in a counter-pulling manner, a main body mechanism is arranged between the lower end cover and the upper end cover, a hand wheel is fixed above the upper end cover through the main body mechanism, a nut with a cover and an upper pressing plate, an upper air inlet is formed in the side face of the upper end cover, and a buffer valve and a lower air inlet are arranged in the side face of the lower end cover.

Description

Manual-automatic integrated pneumatic actuator capable of being automatically switched

Technical Field

The present application relates to a manual-automatic integrated automatically switchable pneumatic actuator and is not intended to be limiting.

Background

The traditional pneumatic actuator with a manual operating mechanism basically adopts a manual bolt or a manual clutch to realize the switching of manual and pneumatic functions, and the principle is that the manual mechanism is connected with the pneumatic actuator executing mechanism by manually inserting the bolt or manually pulling a clutch shifting fork handle during manual operation, so that the manual operation is realized; when automatic operation is needed, the manual mechanism is separated from the pneumatic actuator executing mechanism by manually pulling out the bolt or manually pulling the clutch shifting fork handle in the opposite direction, so that automatic operation is realized. Firstly, the operation is complex, the misoperation is easy, under the condition that the pulling of the bolt is forgotten or the clutch is pulled, the automatic operation is started, and a large impact force can be generated on the bolt and the clutch, so that the bolt is difficult to pull out, and the clutch is not easy to separate. Secondly, traditional structure is complicated, and is with high costs, and production, installation, dismantlement are wasted time and energy. In order to solve the problems, the application provides a manual-automatic integrated pneumatic actuator capable of being automatically switched.

The application comprises the following steps:

in order to solve the problems of complex traditional structure, high cost, time and labor waste in production, installation and disassembly, the application provides a manual-automatic integrated pneumatic actuator capable of being automatically switched.

In order to achieve the above purpose, the present application adopts the following technical scheme:

including lower carriage, valve rod connector, lower end cover, pull rod, main part mechanism, upper end cover, hand wheel, area lid nut, top board, upper air inlet, damper and air inlet down, the lower flange of lower carriage passes through bolt and upper valve gap fixed connection, and upper flange and lower end cover fixed connection, the lower flange passes through reference column and upper flange fixed connection, the valve rod connector is open-type threaded connection, the inside of lower end cover and upper end cover all is provided with the ladder counter bore, and the pull rod is fixed in the inside of ladder counter bore through interior hexagonal cylinder nut, the lower end cover passes through the pull rod to be connected with the upper end cover, be provided with main part mechanism between lower end cover and the upper end cover, the hand wheel passes through main part mechanism, takes lid nut and the top of upper end cover to be fixed, the upper air inlet has been seted up to the side of upper end cover, the side of lower end cover is provided with damper and lower air inlet.

As a further description of the above technical solution:

the main part mechanism includes piston, nut, lead screw, feedback pole move sealing washer, parallel key, cylinder, promotion screw rod, connecting bolt, transition board, piston rod, valve open stopper, direction gag lever post and direction gag lever post O type sealing washer, be provided with the cylinder through the location tang between lower extreme cover and the upper end cover, the piston passes through connecting bolt and transition board and piston rod fixed connection, nut and lead screw threaded connection, the lead screw passes through parallel key and hand wheel fixed connection, the feedback pole passes through location screw thread and nut flexonics, and is provided with the dish spring packing ring between feedback pole and the nut, be provided with feedback pole between feedback pole and the upper end cover and move the sealing washer, the quantity of promotion screw rod is two, and promotes screw rod evenly distributed on the transition board, it passes through connecting bolt, transition board and piston rod body coupling to promote the stopper through the bolt and be connected with the lower terminal surface of direction gag lever post, the direction gag lever post passes nut and upper end cover bolted connection, and the outside of direction gag lever post is provided with direction gag lever post O type sealing washer, the quantity of direction gag lever post is two evenly distributed on the transition board.

As a further description of the above technical solution:

the piston comprises Y-shaped sealing rings, grease storage grooves and guide belts, wherein the number of the Y-shaped sealing rings is two, the Y-shaped sealing rings are positioned at the upper end and the lower end of the piston, and the grease storage grooves and the guide belts are arranged between the Y-shaped sealing rings.

As a further description of the above technical solution:

the upper end cover comprises a hole retainer ring, a sealing ring, a dynamic sealing O-shaped ring, a static sealing O-shaped ring, a lower thrust ball bearing, an oil filling hole, an upper thrust ball bearing, an oil jacket, a TC oil seal, an oil seal gland, an oil filling nozzle and an upper end cover O-shaped ring, wherein the hole retainer ring is arranged at the bottom of the sealing ring, the dynamic sealing O-shaped ring is arranged in the dynamic sealing ring, the static sealing O-shaped ring is arranged in the upper end cover, the lower thrust ball bearing is arranged on the shaft shoulder of the screw rod, the upper thrust ball bearing is arranged in the upper end cover, the shaft ring of the upper thrust ball bearing is arranged at the optical axis of the screw rod, the oil filling hole is arranged in the upper end cover, the TC oil seal is fixedly connected to the oil jacket through the oil seal gland, the oil filling nozzle is arranged at the side end of the upper end cover, and the upper end cover O-shaped ring is arranged between the upper end cover and the cylinder barrel.

As a further description of the above technical solution:

the lower end cover comprises an EM sealing dust ring and a self-lubricating composite bushing, wherein the lower end cover body, an HC-buffer ring and a lower end cover O-shaped ring are arranged at the end part of the lower end cover body, the self-lubricating composite bushing is arranged at the lower part of the lower end cover body, the HC-buffer ring is arranged at the upper end part of the lower end cover body, and the lower end cover O-shaped ring is arranged between the lower end cover and the cylinder barrel.

The application has the beneficial effects that:

the valve can be opened or closed manually by rotating the hand wheel; when the hand is automatically switched, the hand wheel is rotated to ensure that the feedback rod can be switched from the manual state to the automatic state after reaching the designated position. The application ensures that the actuator is simple and visual in manual and automatic operation, free from misoperation, convenient, safe and reliable in manual and automatic state switching, and integrates manual operation and automatic operation, so that the structure is simple and compact, and the cost is reduced.

Description of the drawings:

for a clearer representation of a manual-automatic integrated automatically switchable pneumatic actuator, the following figures are shown;

fig. 1 is a front view of a manual-automatic integrated automatically switchable pneumatic actuator.

Fig. 2 is a top view of a self-manual, integral, automatically switchable pneumatic actuator.

Fig. 3 is a cross-sectional view of a hand-and-self integrated automatically switchable pneumatic actuator.

Fig. 4 is an enlarged view of the part ii of the manual-automatic integrated automatically switchable pneumatic actuator.

Fig. 5 is an enlarged view of the iii portion of the manual-automatic integrated automatically switchable pneumatic actuator.

Fig. 6 is a cross-sectional view of a manual-automatic integrated automatically switchable pneumatic actuator B-B.

Fig. 7 is an enlarged view of the portion of the manual-automatic integrated automatically switchable pneumatic actuator.

Wherein reference numerals in the drawings;

1. a lower bracket; 2. a valve stem connector; 3. a lower end cap; 310. EM sealing dust ring; 311. self-lubricating composite bushings; 312. a lower end cap body; 313. HC-1 buffer ring; 314. an O-shaped ring of the lower end cover; 4. a pull rod; 5. a main body mechanism; 510. a Y-shaped sealing ring; 511. a grease storage tank; 512. a guide belt; 513. a piston; 520. a nut; 521. a screw rod; 522. a feedback lever; 523. a feedback rod moves a sealing ring; 524. a flat key; 525. lifting the screw; 526. a connecting bolt; 527. a transition plate; 528. a piston rod; 529. a valve opening limiting block; 530. a guide limit rod; 531. o-shaped sealing rings of the guide limit rods; 540. a cylinder; 6. an upper end cap; 610. a retainer ring for holes; 611. a seal ring; 612. a dynamic sealing O-shaped ring; 613. static seal O-shaped ring; 614. a lower thrust ball bearing; 615. an oil filling hole; 616. an oil jacket; 617. TC oil seal; 618. an oil seal gland; 619. an oil filling nozzle; 620. an upper end cover O-shaped ring; 624. an upper thrust ball bearing; 7. a hand wheel; 8. a nut with a cover; 9. an upper press plate; 10. an upper air inlet; 11. a buffer valve; 12. and a lower air inlet.

The specific embodiment is as follows:

referring to fig. 1 and 2, the manual operation and automatic switching of the actuator are realized by rotating a hand wheel 7 and transmitting torque to an automatic manual integrated main body mechanism 5 by the hand wheel 7, the automatic manual integrated main body mechanism 5 is connected with an upper end cover 6 and a lower end cover 3 into a whole through a pull rod 4, stepped counter bores are formed in the lower end face of the lower end cover 3 and the upper end face of the upper end cover 6, and two ends of the pull rod 4 are respectively opposite to the pull rod 4 by using inner hexagonal cylindrical nuts. The upper end of the valve rod connector 2 is connected to the lower end screw thread of the piston 528 of the manual and automatic integrated body mechanism 5 through an opening screw thread, and the lower end is connected to the valve rod screw thread through an opening screw thread. The lower end of the lower bracket 1 for supporting is connected with an upper valve cover, and the upper end of the lower bracket is connected with a lower end cover 3 through a bolt.

As shown in fig. 3 and 4, the manual and automatic integrated main body mechanism 5 includes a piston 513, a nut 520, a screw rod 521, a feedback rod 522, a feedback rod moving seal ring 523, a cylinder 540, a lifting screw 525, a connecting bolt 526, a transition plate 527, a piston rod 528, a valve opening stopper 529, a guide limit rod 530, and a guide limit rod O-type seal ring 531.

Wherein, the piston 513 is fixed with the transition plate 527 and the piston rod 528 into a whole by the connecting bolt 526.

The nut 520 is in threaded connection with the screw rod 521, the feedback rod 522 is flexibly connected with the nut 520 through positioning threads, and a disc spring washer is additionally arranged between the feedback rod 522 and the nut 520 so as to ensure that the feedback rod 522 and a through hole to be penetrated through the overground end cover 6 are automatically centered, and the sealing of the feedback rod movable sealing ring 523 is in an optimal state.

The lifting screw rods 525 are two in number and uniformly distributed on the transition plate 527, and are integrally connected with the transition plate 527 and the piston rod 528 through connecting bolts 526 to be fixed together with the piston 513.

As shown in fig. 6, the valve opening limiting block 529 is connected with the lower end surface of the guiding limiting rod 530 through a bolt, the guiding limiting rod 530 passes through a through hole on the flange surface of the nut 520 in clearance fit with the guiding limiting rod, and is connected with the upper end cover 6 through a bolt, and the rod-free side of the actuator is sealed through the guiding limiting rod O-shaped sealing ring 531. The number of the guide limit rods 530 is 2, the guide limit rods are uniformly distributed on the transition plate and are not only used for limiting the rotation of the nuts 520, but also used for converting the rotation motion of the handle wheel 7 into linear motion, and the guide limit rods 530 are designed at fixed intervals and used for ensuring the displacement of the limit piston so as to ensure the stroke of the valve.

As shown in fig. 6 and 7, the upper end cap 6 includes a hole retainer 610, a seal ring 611, a dynamic seal O-ring 612, a static seal O-ring 613, a lower thrust ball bearing 614, an oil filler hole 615, an upper thrust ball bearing 624, an oil jacket 616, a TC oil seal 617, an oil seal gland 618, an oil filler neck 619, and an upper end cap O-ring 620.

The dynamic seal O-shaped ring 612 is embedded in the sealing ring 611 and is used for ensuring tightness between the screw 521 and the sealing ring 611 when the screw 521 rotates. The static seal O-ring 613 is embedded in the upper end cover 6, so as to ensure tightness between the seal ring 611 and the upper end cover 6. The lower thrust ball bearing 614 is mounted on the shoulder of the screw rod 521, the seat ring is mounted in the upper end cover for supporting and transmitting the pulling force when the valve is opened manually, a certain gap is left between the upper end of the sealing ring 611 and the lower thrust ball bearing 614, and the pulling force in the axial direction is ensured to be completely carried by the lower thrust ball bearing 614, which is generally about 0.5 mm. The upper thrust ball bearing 624 seat ring is arranged in the upper end cover, the shaft collar is arranged at the optical axis part of the screw rod 521, the upper end surface of the shaft collar is 0.5-20 mm higher than the shaft shoulder, the lower end surface of the hub of the hand wheel 7 is pressed on the upper end surface of the shaft collar of the upper thrust ball bearing 624, the axial downward thrust is ensured to be completely carried by the lower thrust ball bearing 614, and finally the screw rod 521 is axially fixed through the nut with the cover, so that the screw rod 521 can only rotate and cannot axially displace. The TC oil seal 617 is embedded in the oil jacket 616 and its axial position is fixed by the oil seal gland 618, ensuring that bearing grease filled through the grease nipple 619 does not spill. The upper cover O-ring 620 is used to seal the upper cover 6 with the cylinder 540.

The hole retainer 610 is used to axially fix the seal ring 611.

As shown in fig. 4, the piston 513 includes a Y-ring 510, a grease reservoir 511, and a guide belt 512.

The number of the Y-shaped sealing rings 510 is two, the Y-shaped sealing rings are respectively inlaid at the upper end and the lower end of the piston 513, so that the grease in the grease storage groove 511 can be ensured to exist permanently, the lubricating grease is uniformly coated on the inner wall of the cylinder 540 through the linear movement of the piston 513, and the grease groove 511 and the guide belt 512 are arranged on the piston body between the two Y-shaped sealing rings 510.

As shown in fig. 3 and 5, the lower end cap 3 includes an EM sealing dust ring 310, a self-lubricating composite bush 311, a lower end cap body 312, an HC-1 buffer ring 313, and a lower end cap O-ring 314.

The EM sealing dust ring 310 is embedded at the end of the lower end cap 312, and the self-lubricating composite bushing 311 is embedded at the lower part of the lower end cap 312 for supporting and lubricating the piston rod 528.HC-1 buffer ring 313 is embedded in the upper end of lower end cap 312, and realizes a buffer function by the small diameter body at the lower end of piston 513 and buffer valve 9.

Preferably, the EM sealing dust ring 310 has both a unidirectional sealing effect and a dust-proof effect.

Preferably, the self-lubricating composite bushing 312 with graphite can lubricate the piston rod 528 by graphite, avoiding the need for grease filling; working principle:

the actuator is provided with a lower bracket 1, a valve rod connector 2, a lower end cover 3, a pull rod 4, a manual and automatic integrated main body mechanism 5, an upper end cover 6, a hand wheel 7, a nut with cover 8, an upper pressing plate 9, an upper air inlet 10, a buffer valve 11 and a lower air inlet 12. The lower flange of the lower bracket 1 is connected with the upper valve cover through bolts, and the upper flange is connected with the lower end cover 3 through bolts, and meanwhile, the function of supporting the actuator is achieved. The valve rod connector 2 belongs to an open type threaded connector and is used for connecting a piston rod and a valve core, and is provided with an adjusting amount of 5-20 mm so as to facilitate the installation of the valve core. The lower end cover 3 and the upper end cover 6 are connected in a counter-pulling way through the pull rod 4, stepped counter bores are formed in the lower end face of the lower end cover 3 and the upper end face of the upper end cover 6, and the pull rod 4 is respectively counter-pulled at two ends by using inner hexagonal cylindrical nuts, so that the manual and automatic integrated main body mechanism 5 is clamped between the lower end cover 3 and the upper end cover 6 through positioning rabbets. The hand wheel 7 is connected with the screw rod 521 of the manual and automatic integrated main body mechanism 5 through a flat key 524 to transmit torque, and the screw rod 521 and the hand wheel 7 are axially fixed on the upper end cover 6 through an upper thrust ball bearing 624, a lower thrust ball bearing 614, a nut with a cover 8 and an upper pressing plate 9. The upper air inlet 10 is arranged on the side surface of the upper end cover 6, and the buffer valve 11 and the lower air inlet 12 are arranged on the side surface of the lower end cover 3.

When the valve is closed manually, the hand wheel 7 is rotated clockwise, the hand wheel 7 transmits the rotating force to the screw rod 521 through the flat key 524, the screw rod 521 cannot generate axial displacement under the axial acting force of the lower thrust ball bearing 614 and can only do rotating motion, the screw rod 521 further transmits the rotating force to the nut 520, the nut 520 converts the rotating motion into linear displacement under the force of the guide limit rod 530, the nut 520 moves downwards, the small diameter part of the nut 520 passes through the central hole of the valve opening limit block 529, the lower end surface is in contact with the upper end surface of the transition plate 527, the vertically downward thrust is transmitted to the transition plate 527, the transition plate 527 is pushed to displace downwards, the piston 513 is pushed again, the piston 513 drives the piston rod 528 to move downwards synchronously, and after the lower end surface of the piston 513 is contacted with the upper end surface of the lower end cover 3, the valve is forced to continue to move downwards, so that the valve is in a completely closed state, and the purpose of manually closing the valve is achieved.

When the valve is opened manually, the hand wheel 7 is rotated anticlockwise, the hand wheel 7 transmits the rotating force to the screw rod 521 through the flat key 524, the screw rod 521 cannot generate axial displacement under the axial acting force of the upper thrust ball bearing 624, only the rotating motion can be performed, the screw rod 521 transmits the rotating force to the nut 520, the nut 520 converts the rotating motion into linear displacement under the force of the guide limit rod 530, the nut 520 moves upwards, in the ascending process of the nut 520, the upper flange surface drives the lifting screw 525 to move upwards, the lifting screw 525 and the fixing nut penetrate through the round hole corresponding to the valve opening limit block 529, the transition plate 527 is pulled to move upwards, the piston 513 drives the piston rod 528 to move upwards synchronously, and after the upper end face of the transition plate 527 contacts with the lower end face of the valve opening limit block 529, the valve is forced to continue to move upwards, so that the valve is in a fully opened state, and the purpose of manually opening the valve is achieved.

When the valve is automatically closed and opened, the hand wheel 7 is rotated, the top end of the feedback rod 522 is flush with the upper surface of the upper end cover 6, as shown in the state of fig. 3, at the moment, the lower end surface of the nut 520 is retracted in the central hole of the valve opening limiting block 529 to ventilate the upper air inlet 10 of the actuator, the lower air inlet 12 is exhausted, and the air passes through the gap between the valve opening limiting block 529 and the inner wall of the cylinder 540 to push the piston 513 downwards to move, so as to drive the piston rod 528 to move downwards, and the valve is automatically closed; conversely, the lower air inlet 12 of the actuator is ventilated, the upper air inlet 10 is exhausted, and the air pushes the piston 513 to move upwards, so that the piston rod 528 is driven to move upwards, and the valve is automatically opened.

Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of the application following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the application pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.

It is further understood that the use of relational terms such as "first" and "second", and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The application is not limited to the precise construction which has been described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims

1. But manual from integral type automatic switch over pneumatic actuator, including lower carriage (1), valve rod connector (2), lower extreme cap (3), pull rod (4), main part mechanism (5), upper end cap (6), hand wheel (7), area lid nut (8), top board (9), go up air inlet (10), relief valve (11) and air inlet (12) down, its characterized in that: the lower flange of the lower bracket (1) is fixedly connected with an upper valve cover through bolts, the upper flange is fixedly connected with a lower end cover (3), the lower flange is fixedly connected with the upper flange through a positioning column, the valve rod connector (2) is an open type threaded connector, stepped counter bores are formed in the lower end cover (3) and the upper end cover (6), a pull rod (4) is fixed in the stepped counter bores through inner hexagonal cylindrical nuts, the lower end cover (3) and the upper end cover (6) are connected through the pull rod (4) in a counter-pulling manner, a main body mechanism (5) is arranged between the lower end cover (3) and the upper end cover (6), the hand wheel (7) is fixed above the upper end cover (6) through a main body mechanism (5), a nut (8) with a cover and an upper pressing plate (9), an upper air inlet (10) is formed in the side face of the upper end cover (6), a buffer valve (11) and a lower air inlet (12) are arranged on the side face of the lower end cover (3), the main body mechanism (5) comprises a piston (513), a nut (520), a screw rod (521), a feedback rod (522), a feedback rod movable sealing ring (523), a flat key (524), a cylinder barrel (540), a lifting screw rod (525), a connecting bolt (526), a transition plate (527), a piston rod (528), a valve opening limiting block (529), guide limit rod (530) and guide limit rod O-shaped sealing ring (531), be provided with cylinder (540) through the location tang between lower end cover (3) and upper end cover (6), piston (513) are through connecting bolt (526) and transition board (527) and piston rod (528) fixed connection, nut (520) and lead screw (521) threaded connection, lead screw (521) are through flat key (524) and hand wheel (7) fixed connection, feedback rod (522) are through location screw and nut (520) flexonics, and be provided with dish spring packing ring between feedback rod (522) and nut (520), be provided with feedback rod and move sealing washer (523) between feedback rod (522) and upper end cover (6), the quantity of lifting screw (525) is two, and lifting screw (525) evenly distributed on transition board (527), lifting screw (513) and piston (513) pass through connecting bolt (526), transition board (527) and piston rod (528) an organic whole are connected, valve stopper (529) are opened terminal surface (529) through guide rod (530) and guide limit rod (520) and guide limit rod (530) are connected with guide limit rod (530) through, guide limit rod (530) and guide limit rod (530) are provided with guide limit rod (530) outside limit rod (6), the number of the guide limit rods (530) is two, and the guide limit rods (530) are uniformly distributed on the transition plate (527).

2. The manual-automatic integrated automatically switchable pneumatic actuator of claim 1, wherein: the piston (513) comprises Y-shaped sealing rings (510), grease storage grooves (511) and guide belts (512), the number of the Y-shaped sealing rings (510) is two, the Y-shaped sealing rings (510) are located at the upper end and the lower end of the piston (513), and the grease storage grooves (511) and the guide belts (512) are arranged between the Y-shaped sealing rings (510).

3. The manual-automatic integrated automatically switchable pneumatic actuator of claim 1, wherein: the upper end cover (6) comprises a hole retainer ring (610), a sealing ring (611), a dynamic sealing O-shaped ring (612), a static sealing O-shaped ring (613), a lower thrust ball bearing (614), an oil filling hole (615), an upper thrust ball bearing (624), an oil jacket (616), a TC oil seal (617), an oil seal gland (618), an oil filling nozzle (619) and an upper end cover O-shaped ring (620), the bottom of the sealing ring (611) is provided with the hole retainer ring (610), the dynamic sealing O-shaped ring (612) is arranged in the dynamic sealing ring (611), the static sealing O-shaped ring (613) is arranged in the upper end cover (6), a lower thrust ball bearing (614) is arranged on the shaft shoulder of the screw rod (521), the upper thrust ball bearing (624) is arranged in the screw rod (521), the shaft ring of the upper thrust ball bearing (624) is arranged at the optical axis of the screw rod (521), the oil filling hole (615) is arranged in the upper end cover (616), the inner part of the oil jacket (616) is fixedly connected with the TC oil seal (618), the upper end cover (6) is provided with the oil filling nozzle (619), and the upper end cover (620) is arranged between the upper end cover (6) and the oil filling nozzle (620).

4. The manual-automatic integrated automatically switchable pneumatic actuator of claim 1, wherein: the lower end cover (3) comprises an EM sealing dust ring (310), a self-lubricating composite bushing (311), a lower end cover body (312), an HC-1 buffer ring (313) and a lower end cover O-shaped ring (314), wherein the EM sealing dust ring (310) is arranged at the end part of the lower end cover body (312), the self-lubricating composite bushing (311) is arranged at the lower part of the lower end cover body (312), the HC-1 buffer ring (313) is arranged at the upper end part of the lower end cover body (312), and the lower end cover O-shaped ring (314) is arranged between the lower end cover (3) and a cylinder barrel (540).