Electro-hydraulic linear driver

Abstract

The electro-hydraulic linear driver comprises a cylinder body, a guide sleeve, a piston and a piston rod, a rod cavity and a rodless cavity are formed in the cylinder body, a driving device is arranged at one end of the rodless cavity, a driving rod can penetrate through the piston to extend into a containing cavity of the piston rod, and a hydraulic driving assembly is matched through the driving rod and a transmission input piece. The piston is internally provided with a hydraulic driving assembly and an oil duct communicated with a rod cavity and a rodless cavity, circulation of hydraulic oil among the cavities is achieved through the gear type hydraulic driving assembly or the swash plate plunger type hydraulic driving assembly, a cylinder sleeve outside the piston rod is matched with a shaft rotation limiting structure, axial rotation can be restrained, and the piston rod can rotate stably. The technical problems of a traditional hydraulic system in the aspects of energy efficiency, dynamic response, complex working condition adaptability, safety and the like are solved, the operation stability of the cylinder body can be effectively improved in cooperation with the guide sleeve, the failure rate in the cylinder body is greatly reduced, and comprehensive improvement of the energy efficiency, precision and reliability is achieved through mechanical-electrical-hydraulic deep cooperation.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic components, and in particular relates to an electro-hydraulic linear drive. Background Art

[0002] In industrial engineering, the traditional linear displacement driven hydraulic cylinder is used as an actuator. Compared with electric cylinders and pneumatic cylinders, it has the characteristics of high energy density and stable drive. However, the hydraulic cylinder requires special control components and hydraulic systems for control, and complicated connecting pipes are required between the two. There is a high risk of oil leakage, a high failure rate, a large volume, and large energy loss in electrical and hydraulic transmission. In addition, ordinary hydraulic cylinders are inefficient, and there is a delay in dynamic response during high-speed reciprocating work and insufficient adaptability to complex working conditions. The existing electro-hydraulic push rods and electric cylinders are basically realized by carrying a certain volume of motors, transmission components or hydraulic power units on the cylinder end, and the volume increase is inevitable. Therefore, electro-hydraulic push rods and electric cylinders are still widely used. However, it has not broken away from traditional control structures and methods such as hydraulic drive and mechanical transmission. Cylinders are used for light-load conditions and the compressibility of gas is not easy to control. With the development of technology and the current development of new energy and energy storage technologies, more and more equipment uses electric drive. For example, electric cylinders are used in linear drives. However, electric cylinders have defects such as low driving force, limited application scenarios, and many and precise components, high cost, and complex manufacturing. They cannot meet high-load requirements. Based on the above technical background and current application scenario requirements, we explore a dual-drive method that can be driven by hydraulic power and combined with electric conversion to mechanical transmission to achieve large-load displacement, integrating electric and hydraulic linear drive technologies and devices to solve the above problems. Summary of the Invention

[0003] The present invention provides an electro-hydraulic linear drive, comprising a cylinder body and a guide sleeve, wherein a piston and a piston rod are arranged in the cylinder body, a rod cavity is formed between the cylinder body, the piston rod and the guide sleeve, a rodless cavity is formed between the other end of the piston and the cylinder body, a driving device is arranged at one end of the rodless cavity, and a driving rod is arranged in the cylinder body; a cavity is arranged in the piston rod, a driving rod is fixedly arranged at the end of the output shaft of the driving rod device, the driving rod passes through the piston and extends into the piston rod cavity, and an axially extending key is arranged on the radial circumference of the driving rod; a cavity for installing a hydraulic drive component is arranged inside the piston, and an oil channel for connecting the hydraulic drive component, the rod cavity and the rodless cavity is arranged in the piston; the hydraulic drive component includes a transmission input member connected to the drive rod, an engaging hole is arranged on the transmission input member, and a key groove is arranged on the inner wall of the engaging hole, and the key on the radial circumference of the driving rod can engage with the key groove on the inner side of the engaging hole of the transmission input member.

[0004] Preferably, the hydraulic drive assembly includes an internal gear, an external gear and an oil separator, the external gear is nested inside the internal gear, the oil separator is arranged between the internal gear and the external gear, and the external gear serves as a transmission input component.

[0005] Preferably, the hydraulic drive assembly includes a swash plate support seat, a swash plate, a straight plate, a distribution plate, a plunger assembly between the swash plate and the straight plate, a ball joint, and pressure plates on both sides thereof, which are arranged in sequence; the swash plate support seat, the swash plate, the straight plate, the distribution plate, the plunger assembly, the ball joint, and the pressure plates on both sides thereof are all provided with through holes for the drive rod to pass through, and the swash plate and the straight plate serve as transmission input components.

[0006] Preferably, the piston includes a ring body, a front cover and a rear cover arranged on both sides of the ring body. The ring body is connected to the cylinder body hole axis, the front cover is fixedly connected to the piston rod, and oil passage one and oil passage two are arranged on the ring body. Oil passage one connects the hydraulic drive assembly with the rod chamber, and oil passage two connects the hydraulic drive assembly with the rodless chamber.

[0007] Preferably, the piston includes a housing and a housing rear cover installed behind the housing. The housing is in fit with the cylinder body hole axis, and oil passage one and oil passage two are arranged on the housing. Oil passage one communicates with the rodless chamber, and oil passage two communicates with the rod chamber.

[0008] Preferably, a through hole is provided at the bottom of the cylinder block. The output shaft of the driving device is connected to the drive rod, and a limit groove is arranged near the cylinder block side. A convex ring adapted to the limit groove is fixedly arranged at the end of the drive rod, and the cooperation between the convex ring and the limit groove can offset the axial force of the lead screw.

[0009] Preferably, the piston rod passes through the guide sleeve and extends out of the cylinder block. A cylinder block sleeve is arranged at the end of the piston rod. The bottom of the cylinder block sleeve is fixedly connected to the piston rod through bolts. The cylinder block sleeve is integrally sleeved on the cylinder block and can perform axial reciprocating motion along the cylinder block side wall with the piston rod.

[0010] Preferably, a shaft rotation limit structure is arranged between the cylinder block sleeve and the cylinder block. The shaft rotation limit structure includes a flat key arranged on the side wall of the cylinder block and a flat key groove on the inner wall of the cylinder block sleeve that cooperates with the flat key.

[0011] Preferably, the driving device can adopt a servo motor, a hydraulic motor, an engine including a gearbox, or any device that can provide positive and negative rotation driving forces.

[0012] Preferably, an annular cavity is arranged inside the guide sleeve, and an annular separator is arranged in the annular cavity. The annular separator divides the space in the annular cavity into a high-pressure gas cavity and an oil storage cavity, and an oil passage is arranged on one side of the oil storage cavity to communicate with the rod chamber.

[0013] The present invention has the following beneficial effects: The spline rod is rotated by a motor, and then the hydraulic power is transmitted to the built-in power source of the piston part to output hydraulic power, realizing the axial driving ability. The overall structure integrates a motor, a hydraulic driving component, and an oil compensation device. Compared with the hydraulic cylinders and electric cylinders controlled by traditional hydraulic systems, this electric drive pump and hydraulic control cylinder has a wide range of applicability, strong driving force, and comprehensive load-bearing capacity for external loads. When it is necessary to maintain the working condition, it has a strong locking ability, stable driving performance, realizes double insurance for driving, improves safety performance, reduces control costs, avoids the problems of large volume and weight of traditional hydraulic control, and does not have the problems of insufficient thrust and complex components of traditional electric cylinders. By directly adjusting the output flow through the servo system, "energy supply on demand" is realized, and the overflow and throttling losses are greatly reduced. Brief Description of the Drawings

[0014] Figure 1 is a schematic cross-sectional view of the overall structure of the present invention; Figure 2 is a schematic cross-sectional view of the overall structure during the use of the present invention; Figure 3 is a schematic cross-sectional view of the overall structure of the piston part of the present invention; Figure 4 is a schematic view of the meshing structure of the internal parts of the gear-type hydraulic driving component of the present invention; Figure 5 is a schematic view of the cylinder block structure of the present invention; Figure 6 is a schematic view of the sleeve structure of the present invention; Figure 7 is a schematic cross-sectional view of the internal structure of the sleeve of the present invention; Figure 8 is a schematic cross-sectional view of the overall structure of the plunger-type hydraulic driving component of the present invention; Figure 9 is a schematic view of the overall structure of the driving rod of the present invention; Figure 10 is a schematic cross-sectional view of the driving rod of the present invention.

[0015] Wherein: 1 - cylinder block, 11 - rod chamber, 12 - rodless chamber, 13 - oil port, 14 - cylinder block sleeve, 15 - axial rotation limit structure, 151 - flat key, 152 - flat key groove; 2 - guide sleeve, 21 - annular spacer, 22 - high-pressure gas chamber, 23 - oil storage chamber; 3 - driving device, 31 - driving rod; 4 - piston, 41 - oil passage one, 42 - oil passage two; 5 - piston rod, 51 - lead screw cavity; 611 - front cover, 612 - ring body, 613 - rear cover, 614 - internal gear, 615 - external gear, 616 - oil separation partition block, 617 - meshing hole; 621 - Housing, 622 - Rear cover of the housing, 623 - Swash plate support seat, 624 - Swash plate, 625 - Straight plate, 626 - Oil distribution plate, 627 - Plunger assembly, 628 - Ball hinge, 629 - Pressure plate. Detailed implementation mode

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. 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.

[0017] Embodiment 1: As Figure 1 , Figure 2 shown, an electro-hydraulic linear actuator includes a cylinder block 1 and an annular guide sleeve 2 provided at the cylinder head of the cylinder block 1. Threads are provided on the inner wall of the cylinder head of the cylinder block 1, and an oil port 13 is provided on the side wall of the bottom of the cylinder block 1. The guide sleeve 2 is screwed onto the cylinder head of the cylinder block 1 through threads, and a gasket is provided between the guide sleeve 2 and the cylinder block 1 to prevent oil leakage. A hole is opened at the center of the bottom of the cylinder block 1 of the cylinder block 1, and a driving device 3 is provided on one side of the rodless cavity 12 of the cylinder block 1. The driving rod 31 connected to the output shaft of the driving device 3 penetrates into the cylinder block 1 through the hole at the center of the bottom of the cylinder block 1 of the cylinder block 1, and a piston 4 and a piston rod 5 are provided inside the cylinder block 1.

[0018] As Figure 1-3 shown, the front end of the piston 4 is fixedly connected to the piston rod 5. The piston 4 is in hole-shaft fit with the cylinder block 1. A sealing ring is provided at the joint of the piston 4 and the cylinder block 1. An axial through hole is provided in the middle of the piston 4. The piston rod 5 passes through the guide sleeve 2 and extends out of the cylinder block 1. The piston rod 3 is connected to the guide sleeve 2 in hole-shaft connection. An annular cavity is provided inside the guide sleeve 2, and a movable annular partition 21 is provided in the annular cavity. Annular gaskets are respectively provided on the inner and outer edges of the annular partition 21 to divide the space in the annular cavity into a high-pressure gas cavity 22 and an oil storage cavity 23. An air port is provided on one side of the high-pressure gas cavity 22, and high-pressure gas is filled inside. An oil passage is provided on one side of the oil storage cavity 23 to communicate with the rod cavity 11, and a lead screw cavity 51 is provided inside the piston rod 5.

[0019] The driving device 3 can be a servo motor, a hydraulic motor, an engine with a gearbox, or any driving device with a forward and reverse output shaft. The driving device 3 is fixed to the center of the outer side of the bottom of the cylinder block 1 by bolts, and the output shaft of the driving device 3 is fixedly connected to the driving rod 31. The connection between the driving rod 31 and the output shaft of the driving device 3 is arranged in the central hole at the bottom of the cylinder block 1. A limiting groove is arranged in the central hole, and the diameter of the limiting groove is larger than the diameter of the central hole at the bottom of the cylinder, forming an annular surface. A convex ring adapted to the limiting groove is fixedly arranged at the upper end of the driving rod 31, and the convex ring can abut against the annular surface of the limiting groove to block the axial force of the driving rod 31 during the operation of the piston 4. The driving rod 31 passes through the axial through hole in the middle of the piston 4 and extends into the lead screw cavity 51 inside the piston rod 5. The piston rod 5 is a cylindrical structure with an opening on one side, and a formed flange is arranged at the opening and is fixedly connected to the front end of the piston 4.

[0020] As Figure 3 , Figure 4 shown, the piston 4 includes a front cover 611, a ring body 612, and a rear cover 613. An oil passage 41 and an oil passage 42 are arranged on the ring body 612. The front cover 611 is fixedly connected to the flange of the piston rod 5 by bolts. The hydraulic driving assembly includes side plates connected by the front cover 511 and the rear cover 513, an internal gear 614, an external gear 615, and an oil separation block 616 between the side plates. The oil separation block 516 is arranged between the internal gear 614 and the external gear 615. Symmetrical oil passages are arranged on both sides of the hydraulic driving assembly, and both ends of the symmetrical oil passages are respectively communicated with the oil passage 41 and the oil passage 42. A meshing hole 617 is arranged on the external gear 615; As Figure 9 and Figure 10 shown, the driving rod 31 is a spline shaft, and a spline groove is arranged in the meshing hole 617 of the external gear 615. The spline groove is adapted to the spline of the driving rod 31, and the external gear 615 can rotate through the drive of the driving rod 31. When the internal gear 614 and the external gear 615 rotate in the same direction, on the oil suction side, the gears gradually separate, the volume between the teeth increases to form a negative pressure, and the liquid is sucked in and sealed between the tooth grooves and the oil separation block 616. As the gears rotate, it moves along the cavity to the oil discharge side. On the oil discharge side, the gears re-engage, resulting in a decrease in the sealed volume. The liquid is squeezed out through the oil discharge port, and at the same time, it drives the hydraulic driving assembly to reciprocate axially along the driving rod 31; The driving rod 31 can also be a single-key shaft, and at the same time, the key groove in the meshing hole 617 on the external gear 615 can be a single-key groove adapted to the single-key shaft.

[0021] As Figure 1 , Figure 5 , Figure 6 and Figure 7As shown, a cylinder sleeve 14 is sleeved outside the cylinder block 1. The bottom of the cylinder sleeve 14 is fixedly connected to the end of the piston rod 5. The cylinder sleeve 14 can axially reciprocate along the side wall of the cylinder block 1 driven by the piston rod 5. An axial rotation limiting structure 15 is arranged between the cylinder sleeve 14 and the cylinder block 1. The axial rotation limiting structure 15 includes a flat key 151 arranged on the side wall of the cylinder block 1 and a flat key groove 152 on the inner wall of the cylinder sleeve 14. The cooperation between the flat key 151 and the flat key groove 152 restricts the cylinder block 1 and the cylinder sleeve 14 from circumferentially rotating.

[0022] When the first embodiment is in the working state, all chambers are filled with hydraulic oil. When extending, the piston 5 is located at the bottom of the cylinder block 1. Start the driving device 3. The driving device 3 drives the driving rod 31 to start rotating. The driving rod 31 cooperates with the transmission input member to drive the hydraulic driving assembly to start operating. During the operation of the hydraulic driving assembly, the hydraulic oil enters the first oil passage 41 from the rod chamber 11 and enters the rodless chamber 12 through the second oil passage 42 under the control of the hydraulic driving assembly. At this time, the piston 5 starts to axially move as a whole along the driving rod 31, pushing the piston rod 5 and the cylinder sleeve 14 to extend.

[0023] When the piston rod 5 is to retract into the cylinder block 1, the driving device 3 rotates in the reverse direction, driving the hydraulic driving assembly to distribute the hydraulic oil in the reverse direction. The hydraulic oil is sucked from the rodless chamber 12 through the second oil passage 42, and is reversely distributed to the first oil passage 41 through the symmetric oil passage and then enters the rod chamber 11. The hydraulic oil pushes the piston 4 to move axially backward, driving the piston rod 5 to retract into the cylinder block 1.

[0024] The guide sleeve 2 can play a role in compensating and adjusting the volume difference of the hydraulic oil during the operation of the oil cylinder. When the piston rod 5 retracts, the hydraulic oil enters the rod chamber 11 from the rodless chamber 12. Due to the increase in the flow rate and pressure of the hydraulic oil, the hydraulic oil enters the oil storage chamber 23 through the oil passage on the guide sleeve 2, compressing the space of the high-pressure gas chamber 22 through the annular spacer 21. When the piston rod 5 extends, the hydraulic oil enters the rodless chamber 12 from the rod chamber 11. At this time, the pressure in the rod chamber 11 becomes smaller, and the pressure in the oil storage chamber 23 in the guide sleeve 2 also becomes smaller. The high-pressure gas in the high-pressure gas chamber 22 in the guide sleeve 2 starts to push the annular spacer 21 outward to compensate the oil in the oil storage chamber 23 into the rod chamber 11.

[0025] Embodiment 2: As Figure 8As shown in the figure, the difference between the second embodiment and the first embodiment lies in that in the second embodiment, the piston 4 includes a housing 621 and a housing rear cover 622. An oil passage 41 and an oil passage 42 are respectively provided on the housing rear cover 622. The end of the housing 621 is fixedly connected to the flange of the piston rod 5 by bolts. The housing 621 is in hole-shaft fit with the cylinder block 1. A sealing ring is provided at the mating part of the housing 621 and the cylinder block 1. The hydraulic drive assembly is arranged in the enclosed space of the housing 621 and the housing rear cover 622. The hydraulic drive assembly includes a swash plate support 623 nested inside the housing 521 and a swash plate 624 in clearance fit with the swash plate support 623. An oil distribution plate 626 is nested on the housing rear cover 622 and a straight plate 625 connected to the oil distribution plate. A number of plunger assemblies 627 are evenly distributed in a circle between the swash plate 624 and the straight plate 625. In the middle of the number of plunger assemblies 627, the swash plate 624 and the straight plate 625 are hinged and fitted through a ball joint 628 and pressure plates 629 on both sides of the ball joint 628. The swash plate 624 and the straight plate 625 are transmission input parts. Spline grooves are provided in the axial through holes of the swash plate 624 and the straight plate 625. When the drive rod 31 passes through, the spline grooves can engage with the splines on the drive rod 31. When the drive rod 31 rotates, the swash plate 623 and the straight plate 624 are driven to rotate through the cooperation of the splines and the spline grooves. At this time, the plunger assemblies 627 inside the hydraulic drive device start to move axially back and forth to distribute the oil fluid, driving the piston 4 to move axially back and forth along the drive rod 31.

[0026] During use, the piston 4 is located at the bottom of the cylinder of the cylinder block 1. The drive device 3 is started. At this time, the drive device 3 drives the drive rod 31 to start rotating. During the rotation of the drive rod 31, through the cooperation of the drive rod 31 and the transmission input parts inside the hydraulic drive assembly, the hydraulic drive assembly is driven to start operating. By distributing the oil fluid, the piston 4 moves axially as a whole along the drive rod 31. The oil fluid enters the oil passage 42 from the rod chamber 11, and after being distributed by the hydraulic drive assembly, enters the rodless chamber 12 from the oil passage 41, pushing the piston rod 5 to extend. When the piston rod 5 needs to retract into the cylinder block 1, the drive device 3 rotates in the reverse direction, driving the hydraulic drive assembly to distribute the oil fluid in the reverse direction. The oil fluid is distributed from the rodless chamber 12 through the oil passage 41 to the oil passage 42 and then enters the rod chamber 11, pushing the piston rod 5 to retract.

[0027] In the embodiments of this patent document, the hydraulic drive components are mainly exemplified by internal meshing gear structures, plunger structures, etc. as typical hydraulic components. Specifically, the structural designs, working characteristics, and application methods in hydraulic systems of the two are disclosed, providing specific references for the implementation modes of the technical solutions. However, it should be particularly noted that the above embodiments are only representative examples for explaining the core innovation points, and the actual technical scope involved is not limited to this - in the devices related to this solution, the hydraulic drive components may also include other hydraulic components not specifically described in the embodiments, such as hydraulic motors, hydraulic pumps, cycloidal motors, etc. Hydraulic motors include gear motors and plunger motors, and hydraulic pumps include gear pumps or plunger pumps, etc. These components together with the pump components in the embodiments constitute a complete hydraulic system functional module, and all belong to the technical scope covered by the technical solution of the present invention.

Claims

1. An electro-hydraulic linear actuator, comprising a cylinder block (1) and a guide sleeve (2). A piston (4) and a piston rod (5) are arranged in the cylinder block (1). A rod chamber (11) is formed between the cylinder block (1), the piston rod (5) and the guide sleeve (2). An end of the piston (4) and the cylinder block (1) form a rodless chamber (12), and it is characterized in that: A driving device (3) is provided at one end of the rodless cavity (12), and a driving rod (31) is provided in the cylinder body (1); a cavity is provided in the piston rod (5), and a driving rod (31) is fixedly provided at the end of the output shaft of the driving rod device (3), and the driving rod (31) passes through the piston (4) and extends into the cavity of the piston rod (5), and an axially extending key is provided on the radial circumference of the driving rod (31); a cavity for installing a hydraulic drive component is provided inside the piston (4), and an oil passage for connecting the hydraulic drive component, the rod cavity (11) and the rodless cavity (12) is provided in the piston (4); the hydraulic drive component includes a transmission input member connected to the driving rod (31), and an engaging hole (617) is provided on the transmission input member, and a key groove is provided on the inner wall of the engaging hole (617), and the key on the radial circumference of the driving rod (31) can engage with the key groove on the inner side of the engaging hole (617) of the transmission input member.

2. The electro-hydraulic linear actuator according to claim 1, characterized in that: The hydraulic drive assembly comprises an internal gear (614), an external gear (615) and an oil separator (616); the external gear (615) is nested inside the internal gear (614); the oil separator (616) is arranged between the internal gear (614) and the external gear (615); and the external gear (615) serves as a transmission input component.

3. The electro-hydraulic linear actuator according to claim 1, characterized in that: The hydraulic drive assembly comprises a swash plate support seat (623), a swash plate (624), a straight plate (625), an oil distribution plate (626), and a plunger assembly (627) between the swash plate (624) and the straight plate (625), a ball joint (628), and pressure plates (629) on both sides thereof, which are arranged in sequence; the swash plate support seat (623), the swash plate (624), the straight plate (625), the oil distribution plate (626), the plunger assembly (627), the ball joint (628), and the pressure plates (629) on both sides thereof are all provided with through holes for the driving rod (31) to pass through, and the swash plate (624) and the straight plate (625) serve as transmission input members.

4. The electro-hydraulic linear actuator according to claim 2, characterized in that: The piston (4) includes a ring body (612) and a front cover (611) and a rear cover (613) arranged on both sides of the ring body (612). The ring body (612) is connected to the hole axis of the cylinder body (1). The front cover (611) is fixedly connected to the piston rod (5). The ring body (612) is provided with an oil channel 1 (41) and an oil channel 2 (42). The oil channel 1 (41) connects the hydraulic drive component with the rod chamber (11), and the oil channel 2 (42) connects the hydraulic drive component with the rodless chamber (12).

5. The electro-hydraulic linear actuator according to claim 3, wherein: The piston (4) includes a housing (621) and a housing rear cover (622) mounted behind the housing (621). The housing (621) cooperates with the hole axis of the cylinder body (1). The housing (621) is provided with an oil passage 1 (41) and an oil passage 2 (42). The oil passage 1 (41) is connected to the rodless chamber (12), and the oil passage 2 (42) is connected to the rod chamber (11).

6. A kind of electro-hydraulic linear actuator according to any one of claims 1-5, characterized in that: A through hole is provided at the bottom of the cylinder block (1). The output shaft of the driving device (3) is connected to the driving rod (31), and a limiting groove is provided on one side close to the cylinder block (1). A convex ring adapted to the limiting groove is fixedly provided at the end of the driving rod (31). The cooperation between the convex ring and the limiting groove can offset the axial force of the lead screw (311).

7. An electro-hydraulic linear actuator according to any one of claims 1-5, characterized in that: The piston rod (5) passes through the guide sleeve (2) and extends out of the cylinder block (1). A cylinder block sleeve (14) is provided at the end of the piston rod (5). The bottom of the cylinder block sleeve (14) is fixedly connected to the piston rod (5) by bolts. The cylinder block sleeve (14) is integrally sleeved on the cylinder block (1) and can perform axial reciprocating motion along the side wall of the cylinder block (1) with the piston rod (5).

8. The electro-hydraulic linear actuator according to claim 7, wherein: An axial rotation limiting structure (15) is provided between the cylinder block sleeve (14) and the cylinder block (1). The axial rotation limiting structure (15) includes a flat key (151) provided on the side wall of the cylinder block (1) and a flat key groove (152) on the inner wall of the cylinder block sleeve (14) that cooperates with the flat key (151).

9. The electro-hydraulic linear actuator according to claim 1, characterized in that: The driving device (3) can be a servo motor, a hydraulic motor, an engine including a gearbox, or any device capable of providing forward and reverse driving forces.

10. A kind of electro-hydraulic linear actuator according to any one of claims 1-5, characterized in that: An annular cavity is provided inside the guide sleeve (2). An annular separator (21) is provided in the annular cavity. The annular separator (21) divides the space in the annular cavity into a high-pressure air cavity (22) and an oil storage cavity (23). An oil passage is provided on one side of the oil storage cavity (23) and is communicated with the rodless cavity (11).

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