A small hydraulic actuator

Abstract

The utility model discloses a small -size hydraulic executing device relates to hydraulic actuator technical field, including hydraulic oil pump and telescopic link main part, and hydraulic oil pump includes drive motor, oil tank, oil bladder, two -way pump and oil inlet and outlet adaptation piece, and the oil tank fixed setting is at telescopic link main part one side, is equipped with the accommodation cavity in the oil tank, and the oil tank top is equipped with the front end cover, and the oil bladder sets up in the accommodation cavity, and the oil inlet and outlet adaptation piece sets up at the oil bladder bottom, and the oil inlet and outlet adaptation piece one end extends the oil bladder, and with the oil tank bottom fixed connection, and drive motor fixed setting is at the front end cover top, and drive motor's output shaft penetrates the front end cover top, and extends to the oil bladder with two -way pump connection in, and the oil tank bottom is equipped with the rod cavity oil circuit and the rodless cavity oil circuit, and the oil tank bottom one side is equipped with the air inlet, and the air inlet place is equipped with the air inlet valve spare, has solved the current hydraulic executing device when using, occupies the space big, hydraulic oil utilization rate is low and cannot small -size problem.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic actuator technology, and in particular to a small hydraulic actuator device. Background Technology

[0002] In existing hydraulic actuators, a sealed plastic or iron oil tank is generally used to store hydraulic oil. The oil pump is driven by an oil pump motor to realize the lifting and retraction of the hydraulic cylinder.

[0003] However, these fixed-shape oil tanks have significant drawbacks. As the hydraulic cylinder piston extends, the required tank volume increases accordingly, occupying a large amount of space and reducing the utilization rate of the hydraulic oil, thus affecting the overall performance of the equipment. Especially in special application scenarios such as confined spaces, liquid environments, or vacuum environments, the size of hydraulic actuators presents even greater challenges. Limited space restricts the installation and use of large equipment, while increased equipment size leads to a significant increase in operating costs. This makes it difficult for traditional hydraulic actuators to meet the needs of these special scenarios, resulting in numerous inconveniences and limitations in practical applications.

[0004] To address the aforementioned issues, it is imperative to develop a new type of hydraulic actuator to overcome technical challenges such as fixed tank dimensions, low hydraulic oil utilization, and the inability to achieve miniaturization, thereby meeting the urgent needs for miniaturized and efficient equipment in both routine operations and special environments. Utility Model Content

[0005] Based on this, and in response to the above problems, this utility model proposes a small hydraulic actuator, which solves the problems of large space occupation, low hydraulic oil utilization and inability to be miniaturized in current hydraulic actuators.

[0006] The technical solution of this utility model is: A small hydraulic actuator includes a hydraulic oil pump and a telescopic rod body. The hydraulic oil pump is located on one side of the telescopic rod body and is fixedly connected to the telescopic rod body. The hydraulic oil pump includes a drive motor, an oil tank, an oil bladder, a bidirectional pump, and an inlet / outlet adapter block. The oil tank is fixedly installed on one side of the telescopic rod body. The oil tank has a receiving cavity that extends through the top of the oil tank. The top of the oil tank has a front end cover that fits the oil tank and is sealed to the top of the oil tank to close the receiving cavity. The oil bladder is installed in the receiving cavity. The top of the oil bladder is fixedly and sealed to the front end cover. One end of the front end cover extends into the oil bladder. The inlet / outlet adapter block is installed at the bottom of the oil bladder and is fixedly and sealed to the oil bladder. One end of the inlet / outlet adapter block extends out of the oil bladder and is fixedly connected to the bottom of the oil tank. The drive motor is fixedly installed on the top of the front end cover. The output shaft of the drive motor extends through the top of the front end cover and into the oil bladder to connect with the bidirectional pump for driving the bidirectional pump. The output shaft of the drive motor is rotated and sealed to the top of the front end cover. The bottom of the oil tank is equipped with a rod chamber oil passage and a rodless chamber oil passage. One end of the rod chamber oil passage and the rodless chamber oil passage are connected to the bidirectional pump through an inlet / outlet oil adapter block, and the other end is connected to the telescopic rod body. An air inlet is provided on one side of the bottom of the oil tank, and an air inlet valve is provided at the air inlet.

[0007] Preferably, the intake valve includes an intake valve body, a return spring, and a steel ball. The intake valve body has an inflation chamber and an installation chamber, and a connecting port for connecting the inflation chamber and the installation chamber. The side of the intake valve body with the installation chamber is located inside the intake port and is detachably connected to the intake port. The return spring and the steel ball are fitted together in the installation chamber. The steel ball is located at the lower end of the return spring. One end of the return spring contacts the intake valve body, and the other end contacts the steel ball. One end of the steel ball is pressed by the return spring at the connecting port inside the intake valve body to block the connecting port.

[0008] Preferably, a first sealing ring is provided at the end of the intake valve body that contacts the bottom of the fuel tank. The first sealing ring is embedded in the intake valve body and is detachably connected to the intake valve body.

[0009] Preferably, the end of the air intake valve body with the air chamber is provided with a sealing plug, which is located inside the air chamber and is detachably connected to the air chamber for sealing the air chamber.

[0010] Preferably, a second sealing ring is provided at the end of the sealing plug that contacts the intake valve body. The second sealing ring is embedded in the sealing plug and is detachably connected to the sealing plug.

[0011] Preferably, the output shaft of the drive motor is rotatably connected to the front cover via a rotating bearing, and at least one third sealing ring is provided at the connection between the front cover and the output shaft of the drive motor, with the third sealing ring embedded in the front cover.

[0012] Preferably, the bottom of the oil tank is provided with an oil filling passage, one end of which passes through the bottom of the oil tank and the other end is connected to the inlet / outlet oil adapter block. The bottom of the oil tank is provided with a sealing head, one end of which is located in the oil filling passage and is detachably connected to the oil filling passage. A fourth sealing ring is provided on the side of the sealing head that contacts the bottom of the oil tank.

[0013] Preferably, the telescopic rod body includes a housing, a piston, a piston rod, and an oil pipe. The bottom of the housing is fixedly connected to the bottom of the oil tank. A hydraulic oil chamber is provided inside the housing. The piston rod is located inside the hydraulic oil chamber. The top of the piston rod penetrates the top of the housing and is slidably and sealingly connected to the top of the housing. The piston is located inside the hydraulic oil chamber and is sleeved on the bottom of the piston rod. The piston and the bottom of the piston rod are fixedly and sealingly connected. A hydraulic oil flow chamber is provided inside the piston rod, penetrating the top and bottom of the piston rod. The oil pipe is located inside the hydraulic oil flow chamber and is clearance-fitted with the hydraulic oil flow chamber. The bottom of the oil pipe extends out of the hydraulic oil flow chamber and penetrates the piston, slidingly and sealingly connecting to the piston. The bottom end of the oil pipe is fixedly connected to the bottom of the housing. An oil port is provided on the piston rod, located above the piston. A flow channel is provided inside the oil pipe, penetrating the top and bottom of the oil pipe. The top of the flow channel communicates with the hydraulic oil flow chamber. One end of the rod-side oil passage extends into the housing and communicates with the bottom of the flow channel. The rodless-side oil passage extends into the housing and communicates with the bottom of the hydraulic oil chamber.

[0014] Preferably, the piston rod has a rod head at the top, one end of which is located in the hydraulic oil flow chamber and is detachably connected to the piston rod. The end of the rod head that contacts the hydraulic oil flow chamber is provided with several fifth sealing rings.

[0015] Preferably, the housing includes a cylinder barrel, a cylinder head, and an integrated cylinder head. The cylinder head is located on top of the cylinder barrel and is detachably connected to the cylinder barrel. The end of the cylinder head that contacts the cylinder barrel is provided with several sixth sealing rings. The integrated cylinder head is located at the bottom of the cylinder barrel and is fixedly connected to the bottom of the cylinder barrel.

[0016] Compared with the prior art, the beneficial effects of this utility model are: This invention achieves a reduced overall structural size by integrating the bidirectional pump and inlet / outlet adapter block with the oil tank. Simultaneously, by incorporating an oil bladder within the oil tank, housing the bidirectional pump and inlet / outlet adapter block, and installing an air inlet and air valve at the bottom of the tank, gas can be injected into the oil tank during operation. This alters the internal air pressure, causing the oil bladder to deform and improving hydraulic oil utilization. Compared to traditional hydraulic actuators, the hydraulic actuator described in this invention achieves better performance in a smaller size. It solves the problems of large space occupation, low hydraulic oil utilization, and inability to miniaturize current hydraulic actuators. Attached Figure Description

[0017] Figure 1This is a partial cross-sectional structural schematic diagram of a small hydraulic actuator described in an embodiment of this utility model; Figure 2 This is a partial cross-sectional structural schematic diagram of the hydraulic oil pump described in this embodiment of the utility model; Figure 3 This is as described in the embodiments of this utility model. Figure 2 A magnified schematic diagram of the local structure at point A; Figure 4 This is as described in the embodiments of this utility model. Figure 2 A magnified view of the structure at point B in the middle; Figure 5 This is a cross-sectional structural diagram of the telescopic rod body described in this embodiment of the utility model; Explanation of reference numerals in the attached figures: 10-Hydraulic oil pump, 11-Telescopic rod body, 12-Drive motor, 13-Oil tank, 14-Oil bladder, 15-Two-way pump, 16-Inlet / outlet oil adapter block, 17-Receiving cavity, 18-Front end cover, 19-Third sealing ring, 20-Rod chamber oil passage, 21-Rodless chamber oil passage, 22-Air inlet, 23-Oil filling passage, 24-Air inlet valve, 25-Air inlet valve body, 26-Return spring, 27-Steel ball, 28-Plug, 29-Inflation chamber, 30-Safety Cavity, 31-Connecting port, 32-First sealing ring, 33-Sealing plug, 34-Second sealing ring, 35-Sealing head, 36-Fourth sealing ring, 37-Rotating bearing, 38-Housing shell, 39-Piston, 40-Piston rod, 41-Oil pipe, 42-Hydraulic oil chamber, 43-Hydraulic oil flow chamber, 44-Oil port, 45-Flow channel, 46-Rod head, 47-Fifth sealing ring, 48-Cylinder barrel, 49-Cylinder head, 50-Integrated cylinder head, 51-Sixth sealing ring. Detailed Implementation

[0018] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0019] Example: like Figures 1 to 4 As shown, in order to solve the above problems, this embodiment discloses a small hydraulic actuator, including a hydraulic oil pump 10 and a telescopic rod body 11. The hydraulic oil pump 10 is disposed on one side of the telescopic rod body 11 and is fixedly connected to the telescopic rod body 11. The hydraulic oil pump 10 includes a drive motor 12, an oil tank 13, an oil bladder 14, a bidirectional pump 15, and an inlet / outlet adapter block 16. The oil tank 13 is fixedly installed on one side of the telescopic rod body 11. The oil tank 13 has a receiving cavity 17 that extends through the top of the oil tank 13. The top of the oil tank 13 has a front end cover 18 that fits the oil tank 13 and is sealed to the top of the oil tank 13 to close the receiving cavity 17. The oil bladder 14 is installed inside the receiving cavity 17. The top of the oil bladder 14 is fixedly and sealed to the front end cover 18, and one end of the front end cover 18 extends into the oil bladder. Inside 14, an inlet / outlet oil adapter block 16 is located at the bottom of the oil bladder 14 and is fixed and sealed to the oil bladder 14. One end of the inlet / outlet oil adapter block 16 extends out of the oil bladder 14 and is fixedly connected to the bottom of the oil tank 13. The drive motor 12 is fixedly located at the top of the front cover 18. The output shaft of the drive motor 12 passes through the top of the front cover 18 and extends into the oil bladder 14 to connect with the bidirectional pump 15. The output shaft of the drive motor 12 is fixedly connected to the input end of the bidirectional pump 15 to drive the bidirectional pump 15. The output shaft of the drive motor 12 is rotated and sealed to the top of the front cover 18. The bottom of the oil tank 13 is provided with a rod chamber oil passage 20 and a rodless chamber oil passage 21. One end of the rod chamber oil passage 20 and the rodless chamber oil passage 21 is connected to the bidirectional pump 15 through the inlet and outlet oil adapter block 16, and the other end is connected to the telescopic rod body 11. An air inlet 22 is provided on one side of the bottom of the oil tank 13, and an air inlet valve 24 is provided at the air inlet 22.

[0020] This invention achieves a reduced overall structural volume by integrating the bidirectional pump 15 and the inlet / outlet adapter block 16 with the oil tank 13. Simultaneously, by placing an oil bladder 14 inside the oil tank 13, and housing the bidirectional pump 15 and the inlet / outlet adapter block 16 within the bladder 14, and by providing an air inlet 22 and an air inlet valve 24 at the bottom of the oil tank 13, gas can be injected into the oil tank 13 during operation. This changes the air pressure within the oil tank 13, causing the oil bladder 14 to deform and improving the utilization rate of the hydraulic oil. Compared to traditional hydraulic actuators, the hydraulic actuator described in this invention achieves better performance in a smaller size. It solves the problems of large space occupation, low hydraulic oil utilization, and inability to miniaturize current hydraulic actuators.

[0021] The drive motor 12, bidirectional pump 15, and inlet / outlet oil adapter block 16 can be the same drive motor, bidirectional pump, and inlet / outlet oil adapter block used in existing hydraulic actuators. The top of the oil bladder 14 and the front cover 18 can be fixed and sealed by heat fusion and the addition of sealant. Similarly, the inlet / outlet oil adapter block 16 and the bottom of the oil bladder 14 can be fixed and sealed by heat fusion and the addition of sealant.

[0022] To facilitate gas injection control, this embodiment is modified from the above embodiment. The difference is that the intake valve 24 includes an intake valve body 25, a return spring 26, and a steel ball 27. The intake valve body 25 has an inflation chamber 29 and an installation chamber 30. The intake valve body 25 has a connecting port 31 for connecting the inflation chamber 29 and the installation chamber 30. The side of the intake valve body 25 with the installation chamber 30 is located in the intake port 22 and is detachably connected to the intake port 22. The return spring 26 and the steel ball 27 are fitted together in the installation chamber 30. The steel ball 27 is located at the lower end of the return spring 26. One end of the return spring 26 contacts the intake valve body 25, and the other end contacts the steel ball 27. One end of the steel ball 27 is pressed by the return spring 26 into the connecting port 31 in the intake valve body 25 to block the connecting port 31.

[0023] In use, the air source is connected to one end of the air inlet valve body 25 inflation chamber 29 through a pipe. When the gas in the air source enters the inflation chamber 29, it flows to the connecting port 31. When the gas in the inflation chamber 29 reaches a certain level, it pushes the steel ball 27 upward, opening the connecting port 31, so that the gas in the inflation chamber 29 can enter the mounting chamber 30, and then enter the oil tank 13 from the air inlet 22.

[0024] In order to improve the sealing between the intake valve body 25 and the fuel tank 13, this embodiment is modified based on the above embodiment. The difference from the above embodiment is that a first sealing ring 32 is provided at the end of the intake valve body 25 that contacts the bottom of the fuel tank 13. The first sealing ring 32 is embedded in the intake valve body 25 and is detachably connected to the intake valve body 25.

[0025] The first sealing ring 32 can facilitate the improvement of the sealing between the intake valve body 25 and the oil tank 13.

[0026] As a further preferred embodiment, the inflation chamber 29 is provided with a plug 28, which is inserted into the inflation chamber 29.

[0027] To facilitate closing the air intake valve body 25 when not in use, the air intake valve body 25 has a sealing plug 33 at one end where the air chamber 29 is located. The sealing plug 33 is located inside the air chamber 29 and is detachably connected to the air chamber 29. It is used to seal the air chamber 29. The end of the sealing plug 33 located inside the air chamber 29 is fixedly connected to one end of the plug 28.

[0028] The sealing plug 33 allows the inflation chamber 29 to be sealed when not in use, thereby closing the air intake valve body 25. The plug 28 is made of rubber.

[0029] In order to improve the sealing performance between the intake valve body 25 and the sealing plug 33, this embodiment is modified based on the above embodiment. The difference from the above embodiment is that a second sealing ring 34 is provided at the end of the sealing plug 33 that contacts the intake valve body 25. The second sealing ring 34 is embedded in the sealing plug 33 and is detachably connected to the sealing plug 33.

[0030] The second sealing ring 34 can facilitate the improvement of the sealing performance between the intake valve body 25 and the sealing plug 33.

[0031] To facilitate the drive motor 12 to drive the bidirectional pump 15 and improve the sealing between the drive motor 12 and the front cover 18, this embodiment is modified based on the above embodiment. The difference from the above embodiment is that the output shaft of the drive motor 12 is rotatably connected to the front cover 18 through the rotating bearing 37, and at least one third sealing ring 19 is provided at the connection between the front cover 18 and the output shaft of the drive motor 12. The third sealing ring 19 is embedded in the front cover 18.

[0032] The rotating bearing 37 facilitates the drive motor 12 to drive the bidirectional pump 15, and the third sealing ring 19 facilitates the improvement of the sealing between the drive motor 12 and the front cover 18.

[0033] To facilitate oil filling into the oil bladder 14 and improve the sealing between the sealing head 35 and the oil tank 13, this embodiment is modified based on the above embodiment. The difference from the above embodiment is that the bottom of the oil tank 13 is provided with an oil filling passage 23. One end of the oil filling passage 23 passes through the bottom of the oil tank 13, and the other end is connected to the inlet / outlet adapter block 16. The bottom of the oil tank 13 is provided with a sealing head 35. One end of the sealing head 35 is placed in the oil filling passage 23 and is detachably connected to the oil filling passage 23. A fourth sealing ring 36 is provided on the side of the sealing head 35 that contacts the bottom of the oil tank 13.

[0034] Among them, the oil injection passage 23 extends to the oil inlet / outlet adapter block 16 and is connected to the inside of the oil sac 14.

[0035] In use, simply remove the plug head 35 and inject hydraulic oil into the oil bladder 14 through the oil filling line 23. The plug head 35 prevents hydraulic oil from flowing out of the oil bladder 14. The fourth sealing ring 36 improves the seal between the plug head 35 and the oil tank 13.

[0036] like Figure 5As shown, to facilitate the driving of the telescopic rod body 11, this embodiment is modified based on the above embodiment. The difference from the above embodiment is that the telescopic rod body 11 includes a housing 38, a piston 39, a piston rod 40, and an oil pipe 41. The bottom of the housing 38 is fixedly connected to the bottom of the oil tank 13. A hydraulic oil chamber 42 is provided inside the housing 38. The piston rod 40 is disposed in the hydraulic oil chamber 42. The top of the piston rod 40 penetrates the top of the housing 38 and is slidably and sealingly connected to the top of the housing 38. The piston 39 is disposed in the hydraulic oil chamber 42 and sleeved on the bottom of the piston rod 40. The piston 39 is fixedly and sealingly connected to the bottom of the piston rod 40. A hydraulic oil flow chamber 43 is provided inside the piston rod 40, and the hydraulic oil flow chamber 43 penetrates the piston. The top and bottom of the rod 40 are connected to the hydraulic oil flow chamber 43. The oil pipe 41 is disposed in the hydraulic oil flow chamber 43 with clearance fit. The bottom of the oil pipe 41 extends out of the hydraulic oil flow chamber 43. The bottom of the oil pipe 41 passes through the piston 39 and slides and seals with the piston 39. The bottom end of the oil pipe 41 is fixedly connected to the bottom of the housing 38. The piston rod 40 is provided with an oil port 44, which is located above the piston 39. The oil pipe 41 is provided with a flow channel 45, which passes through the top and bottom of the oil pipe 41. The top of the flow channel 45 is connected to the hydraulic oil flow chamber 43. One end of the rod chamber oil passage 20 extends into the housing 38 and is connected to the bottom of the flow channel 45. The rodless chamber oil passage 21 extends into the housing 38 and is connected to the bottom of the hydraulic oil chamber 42.

[0037] The piston rod 40 has a rod head 46 at the top. One end of the rod head 46 is located in the hydraulic oil flow chamber 43 and is detachably connected to the piston rod 40. The end of the rod head 46 that contacts the hydraulic oil flow chamber 43 is provided with several fifth sealing rings 47.

[0038] In operation, hydraulic oil enters the flow channel 45 of the oil pipe 41 from the rod chamber oil passage 20, then enters the hydraulic oil flow chamber 43, and flows through the gap between the oil pipe 41 and the hydraulic oil flow chamber 43 to the oil port 44, and then enters the hydraulic oil chamber 42 from the oil port 44, thereby pushing the piston 39 downward and retracting the piston rod 40. When hydraulic oil enters the hydraulic oil chamber 42 from the rodless chamber oil passage 21, the piston 39 moves upward, thereby extending the piston rod 40.

[0039] To facilitate installation and improve the sealing between the cylinder head 49 and the cylinder 48, this embodiment is modified based on the above embodiment. The difference from the above embodiment is that the housing 38 includes the cylinder 48, the cylinder head 49 and the integrated cylinder head 50. The cylinder head 49 is located on the top of the cylinder 48 and is detachably connected to the cylinder 48. The end of the cylinder head 49 that contacts the cylinder 48 is provided with a plurality of sixth sealing rings 51. The integrated cylinder head 50 is located at the bottom of the cylinder 48 and is fixedly connected to the bottom of the cylinder 48.

[0040] The piston rod 40 passes through the cylinder head 49 at the top and slides and is sealed to the cylinder head 49. One side of the integrated cylinder head 50 is fixedly connected to the bottom of the oil tank 13. The bottom end of the oil pipe 41 is fixedly connected to the integrated cylinder head 50. One end of the rod chamber oil passage 20 extends into the integrated cylinder head 50 and communicates with the bottom of the flow channel 45. The rodless chamber oil passage 21 extends into the integrated cylinder head 50 and communicates with the bottom of the hydraulic oil chamber 42.

[0041] The cylinder head 49 and cylinder barrel 48 are detachably connected, which facilitates the overall installation of the telescopic rod body 11. The sixth sealing ring 51 improves the sealing performance between the cylinder head 49 and cylinder barrel 48.

[0042] The embodiments described above merely illustrate specific implementations of this utility model, and while the descriptions are detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model.

Claims

1. A small hydraulic actuator, characterized in that, It includes a hydraulic oil pump (10) and a telescopic rod body (11). The hydraulic oil pump (10) is located on one side of the telescopic rod body (11) and is fixedly connected to the telescopic rod body (11). The hydraulic oil pump (10) includes a drive motor (12), an oil tank (13), an oil bladder (14), a two-way pump (15), and an inlet / outlet adapter block (16). The oil tank (13) is fixedly installed on one side of the telescopic rod body (11). The oil tank (13) has a receiving cavity (17) inside, which extends through the top of the oil tank (13). The top of the oil tank (13) has a front end cover (18) that is adapted to the oil tank (13). The front end cover (18) is sealed to the top of the oil tank (13) to close the receiving cavity (17). The oil bladder (14) is installed inside the receiving cavity (17), and the top of the oil bladder (14) is fixed to the front end cover (18). The front cover (18) is sealed and connected. One end of the front cover (18) extends into the oil bladder (14). The oil inlet and outlet adapter block (16) is set at the bottom of the oil bladder (14) and is fixed and sealed to the oil bladder (14). One end of the oil inlet and outlet adapter block (16) extends out of the oil bladder (14) and is fixedly connected to the bottom of the oil tank (13). The drive motor (12) is fixedly set at the top of the front cover (18). The output shaft of the drive motor (12) passes through the top of the front cover (18) and extends into the oil bladder (14) to connect with the bidirectional pump (15) for driving the bidirectional pump (15). The output shaft of the drive motor (12) rotates and is sealed to the top of the front cover (18). The bottom of the oil tank (13) is provided with a rod chamber oil passage (20) and a rodless chamber oil passage (21). One end of the rod chamber oil passage (20) and the rodless chamber oil passage (21) are connected to the bidirectional pump (15) through an inlet / outlet oil adapter block (16), and the other end is connected to the telescopic rod body (11). An air inlet (22) is provided on one side of the bottom of the oil tank (13), and an air inlet valve (24) is provided at the air inlet (22).

2. The small hydraulic actuator according to claim 1, characterized in that, The intake valve component (24) includes an intake valve body (25), a return spring (26), and a steel ball (27). The intake valve body (25) has an inflation chamber (29) and an installation chamber (30). The intake valve body (25) has a communication port (31) for connecting the inflation chamber (29) and the installation chamber (30). The side of the intake valve body (25) with the installation chamber (30) is located in the intake port (22) and is detachably connected to the intake port (22). The return spring (26) and the steel ball (27) are fitted together in the installation chamber (30). The steel ball (27) is located at the lower end of the return spring (26). One end of the return spring (26) is in contact with the intake valve body (25), and the other end is in contact with the steel ball (27). One end of the steel ball (27) is pressed by the return spring (26) at the communication port (31) in the intake valve body (25) to block the communication port (31).

3. A small hydraulic actuator according to claim 2, characterized in that, The intake valve body (25) is provided with a first sealing ring (32) at the end that contacts the bottom of the oil tank (13). The first sealing ring (32) is embedded in the intake valve body (25) and is detachably connected to the intake valve body (25).

4. A small hydraulic actuator according to claim 3, characterized in that, The intake valve body (25) has a sealing plug (33) at one end of the inflation chamber (29). The sealing plug (33) is located inside the inflation chamber (29) and is detachably connected to the inflation chamber (29) for sealing the inflation chamber (29).

5. A small hydraulic actuator according to claim 4, characterized in that, The end of the sealing plug (33) that contacts the intake valve body (25) is provided with a second sealing ring (34). The second sealing ring (34) is embedded in the sealing plug (33) and is detachably connected to the sealing plug (33).

6. A small hydraulic actuator according to claim 5, characterized in that, The output shaft of the drive motor (12) is rotatably connected to the front cover (18) via a rotating bearing (37). At least one third sealing ring (19) is provided at the connection between the front cover (18) and the output shaft of the drive motor (12). The third sealing ring (19) is embedded in the front cover (18).

7. A small hydraulic actuator according to claim 6, characterized in that, The bottom of the oil tank (13) is provided with an oil filling passage (23). One end of the oil filling passage (23) passes through the bottom of the oil tank (13), and the other end is connected to the oil inlet and outlet adapter block (16). The bottom of the oil tank (13) is provided with a sealing head (35). One end of the sealing head (35) is set in the oil filling passage (23) and is detachably connected to the oil filling passage (23). A fourth sealing ring (36) is provided on the side of the sealing head (35) that contacts the bottom of the oil tank (13).

8. A small hydraulic actuator according to claim 1 or 7, characterized in that, The telescopic rod body (11) includes a housing (38), a piston (39), a piston rod (40), and an oil pipe (41). The bottom of the housing (38) is fixedly connected to the bottom of the oil tank (13). A hydraulic oil chamber (42) is provided inside the housing (38). The piston rod (40) is located inside the hydraulic oil chamber (42). The top of the piston rod (40) penetrates through the top of the housing (38) and slides and is sealed to the top of the housing (38). The piston (39) is located inside the hydraulic oil chamber (42) and is sleeved on the bottom of the piston rod (40). The piston (39) is fixed and sealed to the bottom of the piston rod (40). A hydraulic oil flow chamber (43) is provided inside the piston rod (40). The hydraulic oil flow chamber (43) penetrates through the top and bottom of the piston rod (40). The oil pipe (41) is located in the hydraulic oil flow chamber (43). Inside, and with clearance fit with hydraulic oil flow chamber (43), the bottom of oil pipe (41) extends out of hydraulic oil flow chamber (43), the bottom of oil pipe (41) passes through piston (39), and slides and seals with piston (39), the bottom end of oil pipe (41) is fixedly connected to the bottom of housing (38), oil port (44) is provided on piston rod (40), oil port (44) is located above piston (39), flow channel (45) is provided inside oil pipe (41), flow channel (45) passes through the top and bottom of oil pipe (41), the top of flow channel (45) is connected to hydraulic oil flow chamber (43), one end of rod chamber oil passage (20) extends into housing (38) and is connected to the bottom of flow channel (45), rodless chamber oil passage (21) extends into housing (38) and is connected to the bottom of hydraulic oil chamber (42).

9. A small hydraulic actuator according to claim 8, characterized in that, The piston rod (40) is provided with a rod head (46) at the top. One end of the rod head (46) is located in the hydraulic oil flow chamber (43) and is detachably connected to the piston rod (40). The end of the rod head (46) that contacts the hydraulic oil flow chamber (43) is provided with several fifth sealing rings (47).

10. A small hydraulic actuator according to claim 9, characterized in that, The housing (38) includes a cylinder (48), a cylinder head (49), and an integrated cylinder head (50). The cylinder head (49) is located on the top of the cylinder (48) and is detachably connected to the cylinder (48). The end of the cylinder head (49) that contacts the cylinder (48) is provided with several sixth sealing rings (51). The integrated cylinder head (50) is located at the bottom of the cylinder (48) and is fixedly connected to the bottom of the cylinder (48).

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