Hydraulic actuator

Abstract

The invention discloses a hydraulic actuator, and relates to the field of pressure driving equipment, the hydraulic actuator comprises a piston rod and a sealing ring, the sealing ring is wrapped on the outer side of the piston rod, a rubber mat is arranged on the sealing ring, a coil spring is arranged on the outer side of the rubber mat, and the pressure of the coil spring on the sealing ring on the inner side is changed by changing the number of turns of the coil spring winding the piston rod. A coil spring capable of adjusting the extrusion force on the sealing ring is arranged on the outer side of the piston rod, and when the sealing ring is abraded, the outer end of the coil spring is pulled to move around the piston rod to change the extrusion force of the coil spring on the sealing ring on the inner side of the coil spring, so that the sealing ring is inwards attached to the side face of the piston rod; the abrasion clearance on the inner side is compensated through deformation, the frequency of replacing the sealing ring during disassembly and assembly of the hydraulic actuator is reduced, damage to the sealing performance of equipment due to repeated disassembly and assembly is avoided, replacement of quick-wear parts is reduced, and the use cost of the equipment is reduced.

Description

Technical Field

[0001] The present invention relates to an actuator, belonging to the field of pressure-driven devices, and particularly to a hydraulic actuator. Background Art

[0002] Actuators are widely used in fields such as industrial automation and construction machinery. Although the moving speed of hydraulic actuators is relatively slow, they have strong power and positioning effects, can form a stable thrust on the piston rod, and are commonly used for the smooth pushing of heavy objects.

[0003] The most common failure of hydraulic actuators is oil leakage caused by seal damage, which not only affects the thrust of the actuator but also poses certain safety hazards. Common seal damage locations include end covers, guide sleeves, and pistons. Most of the leakage is due to the aging and wear of the sealing rings. If a sealing ring structure that can prevent aging or compensate for wear can be designed, many leakage problems can undoubtedly be solved.

[0004] Regarding the seal problem of hydraulic actuators, those skilled in the art have proposed a hydraulic actuator with relevant designs that can adjust and compensate for the wear of the sealing ring, reducing the frequency of equipment disassembly, installation, and maintenance and extending the service life. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a hydraulic actuator. A coil spring is arranged inside the end cover that is used in the prior art to seal the end of the hydraulic cylinder body. By adjusting the number of turns of the coil spring wound around the piston rod, the pressure exerted by the coil spring on the inner sealing ring is changed, so that the sealing ring worn due to the friction of the piston rod during telescoping is squeezed inward, compensating for the loss of sealing performance caused by wear, reducing the frequency of disassembly and installation of the end cover caused by the wear of the sealing member, thereby avoiding the loss of end cover sealing performance and extending the service life of the equipment.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A hydraulic actuator includes a piston rod and a sealing ring sleeved on the side of the piston rod. The sealing ring is usually sleeved between the piston rod and the structure for sealing the end of the hydraulic cylinder body, or arranged between the piston and the inner wall of the cylinder. Through the elasticity of the sealing ring, not only the sealing effect between the structures is ensured, but also the relative freedom between the structures can be guaranteed.

[0007] Although the machining accuracy between the hydraulic cylinder body and the piston rod and other moving structures in the prior art is extremely high, long-term movement, metal particles that may exist in the oil, and high-temperature working environments will all cause damage to the sealing structure. Frequent disassembly and replacement of the sealing ring for the hydraulic cylinder body result in the loss of vulnerable parts, and the disassembly and installation process also damages the accuracy of the components.

[0008] Therefore, by designing a compensatory extrusion structure for the sealing ring, the wear loss of the sealing ring can be repaired to a certain extent, the replacement frequency of wearing parts can be reduced, and the service life of other parts can be extended. Technical personnel in this field have proposed the design of a compensatory structure.

[0009] A rubber pad is sleeved on the outer side of the piston rod, and the sealing ring is clamped on the inner side of the rubber pad. The rubber pad wraps multiple sealing rings inside it to avoid sealing loss of the installation gap due to wear and advancement of the sealing ring.

[0010] A coil spring is arranged on the outside of the rubber pad, and the outer end of the coil spring is wound around the piston rod. The pressure on the rubber pad inside is changed by adjusting the number of winding turns of the coil spring. The rubber pad squeezes the sealing ring, so that the sealing ring is pressed against the side of the piston rod and deformed to compensate for the wear gap.

[0011] Preferably, an installation groove is opened on the side of the rubber pad, so that the sealing ring can be installed on the inner side of the rubber pad corresponding to the installation groove. The rubber pad material at the installation groove needs to be soft and easy to deform, and can be squeezed and deformed inwardly as the rubber pad is subjected to force to compensate for the wear gap.

[0012] The two ends of the rubber pad are correspondingly fixed with laps, and the rubber pad forms a rubber sleeve surrounding the piston rod through the laps at both ends. The laps at both ends of the interference fit overlap each other, and the originally flat rubber pad can be rolled up to the outside of the piston rod to form an overall sealing structure, thereby avoiding oil leakage due to wear and deformation of the sealing ring.

[0013] Preferably, the side of the piston rod is connected to an end cover corresponding to the rubber pad sliding sleeve, and the end cover is a structure that cooperates with the telescopic movement of the piston rod and seals one end of the hydraulic cylinder body. The prior art usually adopts an integrated design and is used in conjunction with a guide sleeve to seal and guide the piston rod.

[0014] However, in order to cooperate with the installation and function of the rubber pad and the coil spring, the end cover is composed of two parts, the upper and lower parts, which are buckled together, so that the rubber pad and the coil spring are installed inside the end cover, and cooperate with the sealing ring to seal and compensate the active gap between the end cover and the piston rod.

[0015] A mounting ring is fixed on the inner side of the end cover, and the rubber pad is fixed to the inner side of the end cover by clamping the mounting ring. The end of the rubber pad is limited by the mounting ring to avoid leakage at one end of the rubber pad.

[0016] The inner end of the coil spring is fixedly connected to the end cover, which reduces the number of separate components and facilitates equipment installation. In addition, the inner end of the coil spring is fixed to the end cover to prevent it from sliding relative to the piston rod and affecting the pressure regulation accuracy.

[0017] Preferably, an extrusion rubber strip is fixed to the outer wall of the rubber pad corresponding to the coil spring to compensate for the problem of uneven extrusion pressure on the rubber pad caused by the staggered position of the inner and outer layers of the coil spring.

[0018] Limit rings are fixed to the side faces of the top and bottom ends of the rubber pad corresponding to the mounting rings, and the rubber pad is limited and installed in cooperation with the mounting rings inside the end cover. When the rubber pad is subjected to the inward extrusion force of the coil spring, it is not easy to cause leakage problems due to excessive displacement of one end.

[0019] Preferably, wedges are fixed to the outer wall of the mounting ring, and the wedges are in a slope structure at both axial ends of the mounting ring to cooperate with the limit rings on the side of the rubber pad to limit the sliding of the rubber pad.

[0020] Support columns are fixedly arranged between the upper and lower parts of the end cover, and the coil spring is wound around the inside of the end cover through the support columns. On the one hand, the strength of the end cover is strengthened to avoid excessive free space between the end cover and the piston rod, which affects the strength and sealing performance. On the other hand, it is also convenient for the winding and installation of the coil spring. The inner ring of the coil spring is inside the support column, and the outer ring extends into the inside of the end cover through the support column.

[0021] Preferably, a chute is opened on the side face of the end of the end cover, and a slider is slidably clamped inside the chute. The outer end of the coil spring is fixedly clamped with the slider. The slider slides along the chute on the side face of the end cover, pulling the outer end of the coil spring to move around the piston rod, thereby changing the number of turns of the coil spring around the piston rod, and further realizing the adjustment of the extrusion pressure of the coil spring on the inner sealing ring.

[0022] Preferably, a limiting tooth is fixed to one inner wall of the chute, and a positioning gear is meshed with the limiting tooth on the side face of the slider. The positioning gear cooperates with the meshing and positioning method of the limiting tooth to facilitate the positioning of the slider at any position inside the chute.

[0023] Preferably, a lead screw is fixed to the side face of the slider, and the positioning gear is sleeved on the side face of the lead screw by a bearing. As the slider slides, the positioning gear sleeved on the side face of the lead screw rotates accordingly, and always maintains the meshing relationship with the limiting tooth inside the seaweed.

[0024] A rubber block is slidably sleeved on the side face of the lead screw against the positioning gear, and the positioning of the positioning gear is restricted by the frictional force of the rubber block squeezing the positioning gear.

[0025] Preferably, a nut is threadedly sleeved on the side face of the lead screw, and the nut is arranged against the side of the rubber block away from the positioning gear. A spring is arranged between the positioning gear and the rubber block. By screwing the nut, the spring pushes the rubber block away from the positioning gear, thereby facilitating the sliding adjustment of the slider. A gasket is arranged between the spring and the positioning gear to prevent the spring from being damaged.

[0026] Preferably, an L-shaped block is fixed to the side of the slider close to one end of the coil spring, and a buckle is fixed to the side of the outer end of the coil spring corresponding to the L-shaped block. After the upper and lower parts of the end cover are snapped together, the slider is slid along the chute, and the L-shaped block on the side of the slider moves along the side wall of the coil spring and automatically enters the buckle to snap the outer end of the coil spring.

[0027] The present invention discloses a hydraulic actuator, and the beneficial effects thereof are as follows:

[0028] 1. For this hydraulic actuator, a coil spring capable of adjusting the extrusion force on the sealing ring is arranged outside the piston rod. When the sealing ring wears, the outer end of the coil spring is pulled to move around the piston rod to change the extrusion force of the coil spring on the inner sealing ring, so that the sealing ring is pressed inward against the side of the piston rod, compensating for the inner wear gap through deformation, reducing the frequency of disassembling and assembling the hydraulic actuator to replace the sealing ring, avoiding damage to the equipment sealing performance caused by multiple disassembly and assembly, and also reducing the replacement of vulnerable parts, thereby reducing the equipment use cost.

[0029] 2. For this hydraulic actuator, in order to avoid the problem of difficult installation of the sealing ring inside the cylindrical structure, the rubber pad forms a cylindrical structure by surrounding with the laps at both ends and wraps outside the sealing ring, avoiding gap leakage due to wear and deformation compensation of the sealing ring.

[0030] 3. For this hydraulic actuator, in order to cooperate with the installation of the rubber pad and the coil spring outside the piston rod, the existing integral end cover structure is also changed. The end cover is composed of two upper and lower parts that are snapped together, and a limiting ring and a wedge block are also provided in cooperation with the rubber pad, and a support column structure is provided in cooperation with the coil spring to ensure the stability of the structure and prevent leakage.

[0031] 4. For this hydraulic actuator, in order to make the force of the coil spring on the rubber pad balanced, protruding extrusion rubber strips are arranged on the outer wall of the rubber pad to compensate for the gaps in the inner and outer staggered areas of the coil spring, so that the coil spring generates a balanced extrusion force on the whole rubber pad when winding, avoiding an increase in the gap at the staggered gap due to uneven extrusion force. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0034] Figure 2 It is a schematic diagram of the installation structure of the sealing ring, rubber pad and coil spring of the present invention;

[0035] Figure 3 Schematic diagram of the flat structure of the rubber pad of the present invention;

[0036] Figure 4 Schematic diagram of the structure of the rubber pad of the present invention wound into a ring;

[0037] Figure 5 Schematic diagram of the end cover structure of the present invention;

[0038] Figure 6 Schematic diagram of the internal structure of the end cover of the present invention;

[0039] Figure 7 Schematic diagram of the structure and installation of the slider of the present invention;

[0040] Figure 8 Schematic diagram of the cooperation structure between the slider and the coil spring of the present invention.

[0041] In the figure: 1. Piston rod; 2. Sealing ring; 3. Rubber pad; 4. Coil spring; 5. Installation groove; 6. Tap; 7. End cover; 8. Installation ring; 9. Extruded rubber strip; 10. Limiting ring; 11. Wedge block; 12. Support column; 13. Chute; 14. Slider; 15. Limiting tooth; 16. Positioning gear; 17. Lead screw; 18. Rubber block; 19. Nut; 20. Spring; 21. L-shaped block; 22. Buckle. Detailed implementation manners

[0042] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0043] An embodiment of the present invention discloses a hydraulic actuator;

[0044] According to the attached Figure 1 and the attached Figure 2 shown, it includes a piston rod 1, and a sealing ring 2 sleeved on the side of the piston rod 1. The sealing ring 2 is usually sleeved between the piston rod 1 and the structure for sealing the end of the hydraulic cylinder body, or is arranged between the piston and the inner wall of the cylinder body. Through the elasticity of the sealing ring 2, not only the sealing effect between the structures is ensured, but also the relative freedom between the structures can be guaranteed.

[0045] Although the processing accuracy between the hydraulic cylinder body and the piston rod 1 and other active structures in the prior art is extremely high, long-term activities, possible metal particles in the oil, and high-temperature working environment will cause damage to the sealing structure. The hydraulic cylinder body is frequently disassembled and replaced with the sealing ring 2, resulting in the loss of wearing parts. The disassembly and assembly process also damages the accuracy of the components.

[0046] Therefore, by designing a compensatory extrusion structure for the sealing ring 2, the wear loss of the sealing ring 2 can be repaired to a certain extent, the replacement frequency of wearing parts can be reduced, and the service life of other parts can be extended. Technical personnel in this field have proposed the design of a compensatory structure.

[0047] A rubber pad 3 is sleeved on the outer side of the piston rod 1, and a sealing ring 2 is clamped on the inner side of the rubber pad 3. The rubber pad 3 wraps multiple sealing rings 2 inside it to avoid sealing loss in the installation gap due to wear and advancement of the sealing ring 2. It also avoids the problem of oil leakage caused by gaps in the coordination of multiple structures, thereby ensuring the sealing effect. In addition, the rubber pad 3 can also replace related structures with similar functions, as long as it can evenly extrude the inner sealing ring 2 through deformation and ensure the sealing effect without leakage.

[0048] A coil spring 4 is arranged on the outside of the rubber pad 3, and the outer end of the coil spring 4 is wound around the piston rod 1. The pressure on the rubber pad 3 inside is changed by adjusting the number of winding turns of the coil spring 4. The rubber pad 3 squeezes the sealing ring 2, causing the sealing ring 2 to be attached to the side of the piston rod 1 and deform to compensate for the wear gap.

[0049] The coil spring 4 is designed to squeeze the inner sealing ring 2, so that a uniform force can be applied to the sealing ring 2 from the outer annular area thereof, thereby avoiding an increase in the extrusion gap due to uneven force.

[0050] According to the attached Figure 3 and attached Figure 4 As shown, a mounting groove 5 is provided on the side of the rubber pad 3, so that the sealing ring 2 can be mounted on the inner side of the rubber pad 3 corresponding to the mounting groove 5. In addition, the mounting groove 5 can avoid leakage caused by gap installation of the rubber pad 3.

[0051] The material of the rubber pad 3 at the installation groove 5 needs to be soft and easy to deform, so that the rubber pad 3 can be squeezed inward and deformed to compensate for the wear gap as the force is applied to the rubber pad 3 .

[0052] The two ends of the rubber pad 3 are correspondingly fixed with lap heads 6, and the rubber pad 3 forms a rubber sleeve surrounding the piston rod 1 through the lap heads 6 at both ends. The lap heads 6 at both ends of the interference fit overlap each other, and the originally flat rubber pad 3 can be wrapped around the outside of the piston rod 1 to form an overall sealing structure, thereby avoiding oil leakage due to wear and deformation of the sealing ring 2.

[0053] In addition, under the action of the extrusion force, the laps 6 at both ends of the rubber pad 3 are pressed against each other, thus achieving a good sealing effect.

[0054] According to the appended Figure 3 and the appended Figure 5 As shown, a gland 7 is slidably sleeved on the side of the piston rod 1 corresponding to the rubber pad 3. The gland 7 is a structure that cooperates with the telescopic movement of the piston rod 1 and seals one end of the hydraulic cylinder body. The prior art usually adopts an integral design and uses a guide sleeve for sealing and guiding the piston rod 1.

[0055] In order to cooperate with the installation and function of the rubber pad 3 and the coil spring 4, the gland 7 is composed of two upper and lower parts that are buckled together, so that the rubber pad 3 and the coil spring 4 are installed inside the gland 7, and cooperate with the sealing ring 2 to seal and compensate and adjust the moving gap between the gland 7 and the piston rod 1.

[0056] The design of the gland 7 is to cooperate with the installation of the rubber pad 3 and the coil spring 4 on the side of the piston rod 1. The rubber pad 3 and the coil spring 4 are installed through the gland 7 formed by upper and lower clamping. Then, the sealing ring 2 is installed through the installation groove 5 on the inner side of the rubber pad 3. When the piston rod 1 extends and retracts along the gland 7, it will not affect the installation of the rubber pad 3 and the coil spring 4.

[0057] An installation ring 8 is fixed inside the gland 7. The rubber pad 3 is clamped and fixed inside the gland 7 through the installation ring 8, and the end of the rubber pad 3 is limited by the installation ring 8 to avoid the problem of leakage at one end of the rubber pad 3.

[0058] The inner end of the coil spring 4 is fixedly connected to the gland 7, which reduces the number of separate components and facilitates the installation of the equipment. In addition, the fixed connection of the inner end of the coil spring 4 to the gland 7 also avoids its relative sliding with respect to the piston rod 1, which affects the pressure adjustment accuracy.

[0059] An extrusion rubber strip 9 is fixed on the outer wall of the rubber pad 3 corresponding to the coil spring 4. The extrusion rubber strip 9 corresponds to the thickness difference of the staggered area between the inner and outer layers of the outer coil spring 4, and compensates for the problem of uneven extrusion force on the rubber pad 3 caused by the staggered position of the inner and outer layers of the coil spring 4.

[0060] Limit rings 10 are fixed on the side surfaces of the top and bottom ends of the rubber pad 3 corresponding to the installation ring 8, and cooperate with the installation ring 8 inside the gland 7 to limit the installation of the rubber pad 3. When the rubber pad 3 is subjected to the inward extrusion force of the coil spring 4, it is not easy to cause leakage problems due to excessive displacement at one end.

[0061] According to the appended Figure 6 As shown, a wedge block 11 is fixed on the outer wall of the installation ring 8. The wedge block 11 has a slope structure at both axial ends along the installation ring 8, and cooperates with the limit ring 10 on the side of the rubber pad 3 to limit the sliding of the rubber pad 3. When the rubber pad 3 is subjected to the extrusion of the coil spring 4, the limit ring 10 is pressed tightly by the wedge block 11 to prevent it from continuing to move outward and causing gap leakage.

[0062] A support column 12 is fixedly arranged between the upper and lower end covers 7. The coil spring 4 is wound around the inner side of the end cover 7 through the support column 12. On the one hand, it strengthens the strength of the end cover 7, avoiding too large a free space between the end cover 7 and the piston rod 1, which may affect the strength and sealing performance. On the other hand, it also facilitates the winding and installation of the coil spring 4. The inner ring of the coil spring 4 is inside the support column 12, and the outer ring extends into the inner side of the end cover 7 through the support column 12.

[0063] According to the appendix Figure 7 As shown, a chute 13 is opened on the end side of the end cover 7. A slider 14 is slidably clamped inside the chute 13. The outer end of the coil spring 4 is fixedly clamped with the slider 14. The slider 14 slides along the chute 13 on the side of the end cover 7, pulling the outer end of the coil spring 4 to move around the piston rod 1, thereby changing the number of turns of the coil spring 4 around the piston rod 1, and further realizing the adjustment of the extrusion force of the coil spring 4 on the inner sealing ring 2.

[0064] The end cover 7 is divided into two parts by the annular chute 13, and its inner part and outer ring part are respectively connected and fixed by fixing structures such as bolts.

[0065] A limiting tooth 15 is fixed on one inner wall of the chute 13. A positioning gear 16 is arranged on the side of the slider 14 to mesh with the limiting tooth 15. The meshing and positioning method of the positioning gear 16 with the limiting tooth 15 facilitates the positioning of the slider 14 at any position inside the chute 13.

[0066] A lead screw 17 is fixed on the side of the slider 14. The positioning gear 16 is sleeved on the side of the lead screw 17 through a bearing. As the slider 14 slides, the positioning gear 16 sleeved on the side of the lead screw 17 through the bearing rotates accordingly, always maintaining the meshing relationship with the limiting tooth 15 inside the chute 13.

[0067] By changing the sliding limit of the slider 14 to meshing limit through the positioning gear 16, the limiting strength can be significantly enhanced.

[0068] A rubber block 18 is slidably sleeved on the side of the lead screw 17 to press against the positioning gear 16. The positioning of the positioning gear 16 is carried out through the frictional force of the extrusion of the rubber block 18, restricting the rotation of the positioning gear 16.

[0069] A nut 19 is threadedly sleeved on the side of the lead screw 17. The nut 19 is arranged to press against the side of the rubber block 18 away from the positioning gear 16. A spring 20 is arranged between the positioning gear 16 and the rubber block 18. By screwing the nut 19, the spring 20 pushes the rubber block 18 away from the positioning gear 16, thereby facilitating the sliding adjustment of the slider 14. A gasket is arranged between the spring 20 and the positioning gear 16 to prevent the spring 20 from being damaged.

[0070] According to the appendix Figure 8As shown, an L-shaped block 21 is fixed to the side of the slider 14 close to one end of the coil spring 4, and a buckle 22 is fixed to the side of the outer end of the coil spring 4 corresponding to the L-shaped block 21. After the upper and lower parts of the end cap 7 are snapped together, the slider 14 is slid along the chute 13. The L-shaped block 21 on the side of the slider 14 moves along the side wall of the coil spring 4 and automatically enters the buckle 22 to snap the outer end of the coil spring 4.

[0071] In this hydraulic actuator, a coil spring 4 that can adjust the squeezing force on the sealing ring 2 is arranged outside the piston rod 1. When the sealing ring 2 wears, the outer end of the coil spring 4 is pulled to move around the piston rod 1, changing the squeezing force of the coil spring 4 on the inner sealing ring 2, so that the sealing ring 2 is pressed inward against the side of the piston rod 1, compensating for the wear gap inside through deformation, reducing the frequency of disassembling and assembling the hydraulic actuator to replace the sealing ring 2, avoiding damage to the equipment sealing performance caused by multiple disassembly and assembly, and also reducing the replacement of vulnerable parts, thus reducing the equipment usage cost.

[0072] Furthermore, to avoid the problem of difficult installation of the sealing ring 2 inside the cylindrical structure, the rubber pad 3 is formed into a cylindrical structure by surrounding with the lugs 6 at both ends and wrapped outside the sealing ring 2, avoiding gap leakage due to the wear and deformation compensation of the sealing ring 2.

[0073] Still further, to cooperate with the installation of the rubber pad 3 and the coil spring 4 outside the piston rod 1, the structure of the existing integrated end cap 7 is also changed. The end cap 7 is composed of two upper and lower parts that are snapped together, and a limiting ring 10 and a wedge block 11 are also provided in cooperation with the rubber pad 3, and a support column 12 structure is provided in cooperation with the coil spring 4 to ensure the stability of the structure and prevent leakage.

[0074] Even further, to make the force of the coil spring 4 on the rubber pad 3 balanced, an extruded rubber strip 9 is provided on the outer wall of the rubber pad 3 to compensate for the gap in the staggered area inside and outside the coil spring 4, so that when the coil spring 4 is wound, an even squeezing force is generated on the whole rubber pad 3, avoiding an increase in the gap at the staggered gap due to uneven squeezing force.

[0075] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic actuator, comprising a piston rod (1), and a sealing ring (2) sleeved and arranged on the side of the piston rod (1), characterized in that: The outer side of the piston rod (1) is sleeved with a rubber pad (3), and the sealing ring (2) is clamped and arranged on the inner side of the rubber pad (3); A coil spring (4) is arranged on the outside of the rubber pad (3), and the outer end of the coil spring (4) is wound around the piston rod (1) to adjust the pressure on the rubber pad (3) on the inside thereof. The sealing ring (2) is pressed against the side of the piston rod (1) to compensate for wear.

2. The hydraulic actuator according to claim 1, characterized in that: The side of the rubber pad (3) is provided with an installation groove (5) corresponding to the installation of the sealing ring (2), and the two ends of the rubber pad (3) are fixed with corresponding lap joints (6). The rubber pad (3) forms a rubber sleeve surrounding the piston rod (1) through the lap joints (6) at both ends.

3. The hydraulic actuator according to claim 1, characterized in that: An end cover (7) is slidably sleeved on the side of the piston rod (1) corresponding to the rubber pad (3); the end cover (7) is composed of an upper and lower part that are buckled together; a mounting ring (8) is fixed on the inner side of the end cover (7); the rubber pad (3) is fixed to the inner side of the end cover (7) by means of the mounting ring (8); and the inner end of the coil spring (4) is fixedly connected to the end cover (7).

4. The hydraulic actuator according to claim 3, characterized in that: An extruded rubber strip (9) is fixed to the outer wall of the rubber pad (3) corresponding to the coil spring (4), and a limiting ring (10) is fixed to the side surfaces of the top and bottom ends of the rubber pad (3) corresponding to the mounting ring (8).

5. The hydraulic actuator according to claim 3, characterized in that: A wedge block (11) is fixed to the outer wall of the mounting ring (8), a support column (12) is fixedly arranged between the upper and lower parts of the end cover (7), and the coil spring (4) is wound around the support column (12) and arranged on the inner side of the end cover (7).

6. The hydraulic actuator according to claim 3, characterized in that: A sliding groove (13) is provided on the side surface of the end of the end cover (7), a sliding block (14) is slidably engaged inside the sliding groove (13), and the outer end of the coil spring (4) is fixedly engaged with the sliding block (14).

7. The hydraulic actuator according to claim 6, characterized in that: A limiting tooth (15) is fixed on an inner wall of one side of the slide groove (13), and a positioning gear (16) is provided on the side surface of the slide block (14) that meshes with the limiting tooth (15).

8. The hydraulic actuator according to claim 7, characterized in that: A screw rod (17) is fixed on the side of the slider (14), a bearing of the positioning gear (16) is sleeved on the side of the screw rod (17), and a rubber block (18) is slidably sleeved on the side of the screw rod (17) against the positioning gear (16).

9. The hydraulic actuator according to claim 8, characterized in that: A nut (19) is threadedly sleeved on the side of the screw rod (17), and the nut (19) is arranged to press against a side of the rubber block (18) away from the positioning gear (16). A spring (20) is arranged between the positioning gear (16) and the rubber block (18).

10. The hydraulic actuator according to claim 6, characterized in that: An L-shaped block (21) is fixed to the side surface of the slider (14) close to one end of the coil spring (4), and a buckle (22) is fixed to the side surface of the outer end of the coil spring (4) corresponding to the L-shaped block (21).

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