Electro-hydraulic variable-stroke actuator with seat cushioning and method of actuating same

Abstract

The application provides an electro-hydraulic variable valve actuator and an execution method thereof, and belongs to the field of valve mechanisms of internal combustion engines. The problems of too fast seating speed and large impact of the existing electro-hydraulic variable valve mechanism in the buffering performance are solved. The electro-hydraulic variable valve actuator comprises a driving upper cavity, a driving middle cavity, a driving lower cavity, a buffering upper cavity, a buffering middle cavity and a buffering lower cavity. The driving upper cavity is composed of a cylinder body, an upper end surface of a valve sleeve and a valve piston. The driving middle cavity is composed of an inner surface of the valve sleeve and an upper end of the valve piston. The driving lower cavity is composed of a lower end of the valve piston, the inner surface of the valve sleeve and an upper end surface of a cylinder cover. The buffering upper cavity is composed of the cylinder body and an upper end surface of a buffering piston. The buffering middle cavity is composed of a buffering inner ring groove and a side surface of the buffering piston. The buffering lower cavity is composed of the cylinder body and a lower end surface of the buffering piston. The electro-hydraulic variable valve actuator is mainly used for realizing seating buffering.

Description

Technical Field

[0001] This invention belongs to the field of internal combustion engine valve train mechanisms, and in particular relates to an electro-hydraulic variable valve train actuator and its execution method for achieving seat cushioning. Background Technology

[0002] Traditional valve trains consist of cams, tappets, pushrods, rocker arms, and valves, making them a purely mechanical mechanism. While this mechanism boasts advantages such as simple structure and high reliability, increasing demands on valve timing lead to problems like bulkiness and impact noise. Furthermore, the purely mechanical nature of the mechanism makes changing valve timing parameters difficult, limiting the ability of traditional internal combustion engines to adapt their valve timing strategies to different operating conditions. Variable valve timing technology can adjust valve timing and lift based on engine load and speed, meeting the needs of various operating conditions. Electro-hydraulic camless variable valve timing offers high power density and flexible structural flexibility. However, current electro-hydraulic variable valve timing mechanisms still suffer from issues such as excessively fast settling speed and significant impact in terms of cushioning performance. Summary of the Invention

[0003] In view of this, the present invention aims to propose an electro-hydraulic variable gas distribution actuator and its execution method for realizing seat cushioning, so as to solve the problem that the existing electro-hydraulic variable gas distribution mechanism has excessively fast seating speed and large impact in terms of cushioning performance.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: an electro-hydraulic variable valve timing actuator for seat cushioning, comprising an upper drive chamber, a middle drive chamber, a lower drive chamber, an upper buffer chamber, a middle buffer chamber, and a lower buffer chamber. The upper drive chamber is formed by a cylinder body, the upper end face of a valve sleeve, and a valve piston. The middle drive chamber is formed by the inner surface of a valve sleeve and the upper end of a valve piston. The lower drive chamber is formed by the lower end of a valve piston, the inner surface of a valve sleeve, and the upper end face of a cylinder head. The upper buffer chamber is formed by a cylinder body and the upper end face of a buffer piston. The middle buffer chamber is formed by a buffer inner annular groove and the side surface of a buffer piston. The lower buffer chamber is formed by a cylinder body and the lower end face of a buffer piston. The cylinder body has a medium-pressure oil port at the lower buffer chamber, which can be blocked by the buffer piston. An oblique oil passage is formed on the cylinder body. The cylinder block is connected to a medium-pressure oil port in the oil passage. Both the medium-pressure oil port and the drive lower chamber are connected to the medium-pressure oil rail. The cylinder block has a drive inner ring groove and a control oil port in the drive middle chamber. The control oil port is connected to a reversing valve through a pipeline. The reversing valve is connected to the low-pressure oil rail and the high-pressure oil rail. The valve sleeve has a radial oil port in the drive middle chamber, which is connected to the drive inner ring groove. The valve sleeve has multiple lift control oil holes in the drive lower chamber. The multiple lift control oil holes are arranged along the axial direction of the valve sleeve. The lift control oil holes can be blocked by the air valve piston. A first check valve is provided between the connection passage of the drive upper chamber and the buffer upper chamber and the connection passage of the drive middle chamber and the buffer middle chamber. A second check valve is provided between the drive lower chamber and the buffer lower chamber. A buffer groove is provided on the buffer piston, and a buffer spring is provided below the buffer piston.

[0005] Furthermore, the valve sleeve is provided with a fan-shaped annular groove and a one-way oil inlet, and the fan-shaped annular groove and the one-way oil inlet are connected to drive the lower chamber.

[0006] Furthermore, an extension block is provided on the outer side of the cylinder block, and a third one-way valve is provided on the extension block. The third one-way valve is connected to the medium-pressure oil rail. After passing through the third one-way valve, the medium-pressure oil enters the drive lower chamber through the fan-shaped annular groove and the one-way oil inlet.

[0007] Furthermore, the valve sleeve is connected to the worm gear, and the worm gear meshes with the worm.

[0008] Furthermore, a separation block is provided on the cylinder body, and an adjustment knob is provided at the bottom of the separation block, with the adjustment knob in contact with one end of the buffer spring.

[0009] Furthermore, a sealing block is provided at the bottom of the separating block, and the adjusting knob is located on the sealing block.

[0010] Furthermore, the buffer groove is a stepped groove structure, and the flow area of ​​the stepped groove gradually decreases from top to bottom.

[0011] Furthermore, both the first and second check valves are built-in structures, and the flow rate of the first check valve is greater than that of the second check valve.

[0012] The present invention also provides an execution method for an electro-hydraulic variable gas distribution actuator, as detailed below: When the system's working valve is open, the reversing valve connects to the high-pressure oil rail. High-pressure oil flows from the lift control oil hole and the drive inner ring groove to the drive middle chamber, and enters the drive upper chamber and buffer upper chamber through the first check valve. The high-pressure oil pushes the valve piston and buffer piston downward. When the buffer piston moves downward, the hydraulic oil in the buffer lower chamber connects to the medium-pressure oil rail through the medium-pressure oil port. When the valve piston moves downward, the hydraulic oil in the drive lower chamber enters the inclined oil passage through the lift control oil hole, and enters the buffer lower chamber through the second check valve, finally connecting to the medium-pressure oil rail. When the lower edge of the buffer piston moves down to completely cover the medium-pressure oil port, the buffer piston stops moving. When the lower edge of the valve piston moves down to completely block the lift control oil hole, the valve piston stops moving. When the valve begins to fall back, the reversing valve connects the low-pressure oil rail. Due to the influence of the first check valve, the high-pressure oil in the upper drive chamber and the high-pressure oil in the upper buffer chamber can only connect to the corresponding control port of the middle drive chamber through the buffer groove on the buffer piston. Therefore, when the valve just begins to fall back, the upper buffer chamber is in a high-pressure state. At this time, the buffer piston is in the lower position. As the hydraulic oil flows through the buffer groove to the control port, the oil pressure in the upper buffer chamber begins to drop. Under the action of the buffer spring and the middle pressure oil, the buffer piston is pushed upward, which reduces the flow area of ​​the buffer groove, thereby limiting the outflow speed of the high-pressure oil, thus reducing the sitting speed and achieving the sitting buffer effect.

[0013] Furthermore, by driving the worm gear with a motor to rotate the worm wheel, and connecting the rotary valve sleeve through the keyway, the lift control oil hole on the valve sleeve is switched with the oil passage on the left side leading to the lower buffer chamber, thereby changing the position where the oil hole is completely covered when the valve piston is at its maximum lift, thus realizing the lift change.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses only one directional valve to adjust valve timing, which takes up less space compared to using a proportional valve.

[0015] 2. The lift of the valve in this invention is controlled by a motor, and the valve timing is controlled by the timing of the reversing valve, which can realize independent control of lift and timing.

[0016] 3. The rotary adjustment knob of the present invention can effectively change the buffering effect and can make up for the problem of poor buffering caused by machining errors, leakage and other reasons. Adjusting the knob can improve the consistency of multiple cylinders.

[0017] 4. The valve of this invention achieves flow regulation through pressure balance during valve seating, thereby achieving seating buffering. This pressure balance method can, to a certain extent, avoid problems such as excessive buffering and viscosity changes due to temperature rise. It also has a good buffering effect and can effectively reduce seating impact.

[0018] 5. This invention employs a worm gear mechanism, and the valve sleeve and the valve piston move independently, resulting in a very small torque requirement for driving the valve sleeve to rotate; there is a certain repeating angle between the radial oil hole on the valve sleeve and the oil passage connecting to the cylinder. Therefore, multiple cylinders in different timing states can be controlled simultaneously by a single motor.

[0019] 6. This invention reduces the oil passage length and thus the oil cavity volume by using a built-in one-way valve and an oblique oil passage, which helps to improve response. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic cross-sectional view of an electro-hydraulic variable gas distribution actuator for achieving seat cushioning according to the present invention. Figure 2 This is a three-dimensional structural diagram of an electro-hydraulic variable gas distribution actuator for achieving seating buffering according to the present invention; Figure 3 This is a three-dimensional structural cross-sectional diagram of an electro-hydraulic variable gas distribution actuator for achieving seating buffering according to the present invention; Figure 4 This is an enlarged schematic diagram of the connection between the valve sleeve and the cylinder body according to the present invention; Figure 5 This is a schematic diagram of the high-pressure oil during the downward movement of the drive valve in the high-lift phase of the present invention. Figure 6 This is a schematic diagram of the hydraulic fluid during the downward operation of the drive valve at high lift, as described in this invention. Figure 7 This is a schematic diagram of the low-pressure oil during the valve retraction process at high lift as described in this invention. Figure 8 This is a schematic diagram of the hydraulic fluid during the valve retraction process at high lift as described in this invention. Figure 9 This is a structural diagram of an electro-hydraulic variable gas distribution actuator for achieving seating buffering as described in this invention in AMESim. Figure 10 This is a piston lift curve in AMESim for an electro-hydraulic variable gas distribution actuator that achieves seat cushioning as described in this invention. Figure 11This is a diagram of the piston displacement curve in AMESim for an electro-hydraulic variable gas distribution actuator that achieves seating buffering according to the present invention. Figure 12 This is a schematic diagram of the three-dimensional structure of the buffer piston buffer groove described in this invention; Figure 13 This is a three-dimensional cross-sectional structural diagram of the fan-shaped annular groove and one-way oil inlet on the valve sleeve according to the present invention; Figure 14 This is a schematic cross-sectional view of the two-dimensional valve sleeve structure described in this invention.

[0021] 1-Cylinder block, 2-Buffer piston, 3-Separator block, 4-Buffer spring, 5-Adjusting knob, 6-Sealing block, 7-Valve piston, 8-Valve sleeve, 9-Extension block, 10-Worm gear, 11-Worm, 12-Cylinder head, 13-First check valve, 14-Second check valve, 15-Angled oil passage, 16-Medium pressure oil port, 17-Buffer inner ring groove, 18-Drive inner ring groove, 19-Control oil port, 20-Sector-shaped ring groove, 21- 22 - One-way oil inlet, 23 - Radial oil inlet, 24 - Lift control oil hole, 25 - Reversing valve, 26 - Low-pressure oil rail, 27 - High-pressure oil rail, 28 - High-pressure oil flow line, 29 - Medium-pressure oil flow line one, 30 - Low-pressure oil flow line, 31 - Medium-pressure oil flow line two, 32 - Control oil supply, 33 - Medium-pressure oil supply, 34 - Drive chamber and air valve modeling, 35 - Buffer chamber modeling, 36 - Actuator model. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0023] See Figure 1-14This embodiment describes an electro-hydraulic variable valve timing actuator for seat cushioning. It includes an upper drive chamber, a middle drive chamber, a lower drive chamber, an upper buffer chamber, a middle buffer chamber, and a lower buffer chamber. The upper drive chamber is formed by a cylinder body 1, the upper end face of a valve sleeve 8, and a valve piston 7. The middle drive chamber is formed by the inner surface of the valve sleeve 8 and the upper end of the valve piston 7. The lower drive chamber is formed by the lower end of the valve piston 7, the inner surface of the valve sleeve 8, and the upper end face of a cylinder head 12. The upper buffer chamber is formed by the cylinder body 1 and the upper end face of a buffer piston 2. The middle buffer chamber is formed by a buffer inner annular groove 17 and the side surface of the buffer piston 2. The lower buffer chamber is formed by the cylinder body 1 and the lower end face of the buffer piston 2. A medium-pressure oil port 16 is provided in the lower buffer chamber of the cylinder body 1. The medium-pressure oil port 16 can be blocked by the buffer piston 2. An oblique oil passage 15 is provided on the cylinder body 1, and the oblique oil passage 15 connects to the medium-pressure oil port 16. Both the pressure port 16 and the drive lower chamber are connected to the medium-pressure oil rail 27. The cylinder body 1 is provided with a drive inner ring groove 18 and a control oil port 19 in the drive middle chamber. The control oil port 19 is connected to the reversing valve 24 through a pipeline. The reversing valve 24 is connected to the low-pressure oil rail 25 and the high-pressure oil rail 26. The valve sleeve 8 is provided with a radial oil port 22 in the drive middle chamber. The radial oil port 22 is connected to the drive inner ring groove 18. The valve sleeve 8 is provided with a plurality of lift control oil holes 23 in the drive lower chamber. The plurality of lift control oil holes 23 are arranged along the axial direction of the valve sleeve 8. The lift control oil holes 23 can be blocked by the air valve piston 7. A first one-way valve 13 is provided between the connecting passage of the drive upper chamber and the buffer upper chamber and the connecting passage of the drive middle chamber and the buffer middle chamber. A second one-way valve 14 is provided between the drive lower chamber and the buffer lower chamber. A buffer groove is provided on the buffer piston 2. A buffer spring 4 is provided below the buffer piston 2. This embodiment can achieve variable valve lift and timing and a good seat cushioning effect using only one reversing valve 24 and motor. The valve piston 7 achieves the duration of the maximum lift by blocking the lift control oil hole 23.

[0024] In this embodiment, the valve sleeve 8 is provided with a fan-shaped annular groove 20 and a one-way oil inlet 21, which connect to the drive lower chamber. An extension block 9 is provided on the outer side of the cylinder body 1, and a third one-way valve is provided on the extension block 9. The third one-way valve connects to the medium-pressure oil rail 27. After passing through the third one-way valve, the medium-pressure oil enters the drive lower chamber through the fan-shaped annular groove 20 and the one-way oil inlet 21. To ensure normal oil flow at the start of the seating process, a system is established as follows... Figure 8 The diagram shows the hydraulic circuits for the drive lower chamber and the buffer lower chamber. When the buffer piston 2 begins to move upward, medium-pressure oil enters the buffer lower chamber through the inclined oil passage 15 and the second one-way valve 14. When the pneumatic valve piston 7 begins to move upward, medium-pressure oil enters the drive lower chamber through the one-way valve on the outside of the extension block, through the fan-shaped annular groove 20 on the valve sleeve, and the one-way oil inlet 21, thus enabling the pneumatic valve piston 7 to fall back normally.

[0025] The valve sleeve 8 is connected to the worm wheel 10, and the worm wheel 10 meshes with the worm 11. The worm 11 is driven by a motor to rotate the worm wheel 10. The valve sleeve 8 is connected to the keyway to rotate the valve sleeve 8, thereby switching the lift control oil hole 23 on the valve sleeve 8 with the oil passage on the left side leading to the lower buffer chamber. This changes the position where the oil hole is completely covered when the air valve piston 7 is at its maximum lift, thus realizing the lift change.

[0026] A separation block 3 is provided on the cylinder body 1, a sealing block 6 is provided at the bottom of the separation block 3, and an adjustment knob 5 is provided at the bottom of the separation block 3. The adjustment knob 5 is located on the sealing block 6 and is in contact with one end of the buffer spring 4. The buffer piston 2 is activated by a change in force balance caused by pressure change. Therefore, by adjusting the knob 5 to change the preload of the buffer spring 4 at the zero displacement moment of the buffer piston 2, the buffering effect of the buffer piston 2 can be effectively changed.

[0027] The buffer groove has a stepped groove structure, such as... Figure 12 As shown, the flow area of ​​the stepped groove gradually decreases from top to bottom. At high lift, the upper buffer chamber is under high pressure, and the buffer piston 2 is in the lower position, resulting in a larger flow area and a smaller buffering effect. As the piston moves upward, the oil pressure in the driving upper chamber and the upper buffer chamber decreases, and the buffer piston 2 also moves upward, reducing the flow area and gradually strengthening the buffering effect. When about to settle, the effective flow area of ​​the buffer piston 2, due to the effect of the stepped groove, begins to decrease rapidly with the decreasing lift, achieving the buffering effect of settling. The lift of the buffer piston is as follows... Figure 11 As shown.

[0028] The buffer piston 2 achieves force balance under the combined action of the buffer spring 4, the upper buffer chamber oil pressure, and the lower buffer chamber oil pressure. By converting the signal of the pressure change in the upper chamber into the force change in the upper part of the buffer piston, the movement of the buffer piston 2 is realized, and the buffer is achieved by sitting and buffering under the combined action of the buffer groove.

[0029] Both the first check valve 13 and the second check valve 14 are built-in structures, with the flow rate of the first check valve 13 being greater than that of the second check valve 14. Through the built-in check valves and the oil circuit design of the cylinder 1 and valve sleeve 8, the normal return and buffering functions of the buffer piston 2 and the pneumatic valve piston 7 are ensured, while also reducing space occupation.

[0030] This embodiment describes the execution method of the aforementioned electro-hydraulic variable pneumatic actuator, as detailed below: When the system's working valve opens, the reversing valve 24 connects to the high-pressure oil rail 26. High-pressure oil flows from the lift control oil hole 23 and the drive inner ring groove 18 to the drive intermediate chamber, and enters the drive upper chamber and buffer upper chamber through the first one-way valve 13. The high-pressure oil pushes the valve piston 7 and the buffer piston 2 downwards, as... Figure 5As shown. When the buffer piston 2 moves downward, the hydraulic oil in the lower buffer chamber is connected to the medium pressure oil rail 27 through the medium pressure oil port 16. When the air valve piston 7 moves downward, it drives the hydraulic oil in the lower chamber to enter the inclined oil passage 15 through the lift control oil hole 23, and then enters the lower buffer chamber through the second check valve 14, finally connecting to the medium pressure oil rail 27.

[0031] When the lower edge of the buffer piston 2 descends to completely cover the intermediate pressure oil port 16, if it continues to descend, it will begin to compress the hydraulic oil. Therefore, the buffer piston 2 will stop moving after covering the intermediate pressure oil port 16 in the lower chamber. Similarly, when the lower edge of the valve piston 7 descends to completely block the lift control oil port 23, the valve piston 7 stops moving. Figure 6 As shown.

[0032] It should be noted that stopping piston movement by blocking the oil port will cause some fluctuation in hydraulic oil pressure due to the volume of the hydraulic oil chamber. This will result in a continuous 0.2mm vibration at the maximum valve lift. Figure 10 As shown, this is acceptable for the gas distribution mechanism.

[0033] When the valve begins to fall back, the reversing valve 24 connects the low-pressure oil rail 25. Due to the influence of the first one-way valve 13, the high-pressure oil in the driving upper chamber and the high-pressure oil in the buffer upper chamber can only connect to the corresponding control oil port 19 of the driving middle chamber through the buffer groove on the buffer piston 2. Figure 7 As shown. Therefore, when the air valve just begins to fall back, the upper chamber of the buffer is under high pressure. At this time, the buffer piston 2 is in the lower position. As the hydraulic oil flows through the buffer groove to the control oil port 19, the oil pressure in the upper chamber of the buffer begins to drop. Under the action of the buffer spring 4 and the medium pressure oil, the buffer piston 2 is pushed upward, which reduces the flow area of ​​the buffer groove, thereby limiting the outflow speed of the high pressure oil, thus achieving the purpose of reducing the sitting speed and realizing the buffering effect of sitting.

[0034] The buffer groove has a stepped groove structure, such as... Figure 12 As shown, the flow area of ​​the stepped groove gradually decreases from top to bottom. Therefore, at high lift, the upper buffer chamber is under high pressure, the buffer piston 2 is in the lower position, the flow area is large, and the buffering effect is small; as the piston moves upward, the oil pressure in the driving upper chamber and the upper buffer chamber decreases, and the buffer piston 2 also moves upward, the flow area decreases, and the buffering effect gradually strengthens; when it is about to sit down, the effective flow area of ​​the buffer piston 2 begins to decrease rapidly with the decrease in lift due to the effect of the stepped groove, achieving the buffering effect of sitting down. The lift of the buffer piston is as follows: Figure 11 As shown.

[0035] Because the lift control uses a port-blocking mechanism, to ensure normal oil flow at the start of the seating process, a system is established as follows: Figure 8The diagram shows the hydraulic circuits for the drive lower chamber and the buffer lower chamber. When the buffer piston 2 begins to move upward, medium-pressure oil enters the buffer lower chamber through the inclined oil passage 15 and the second one-way valve 14. When the pneumatic valve piston 7 begins to move upward, medium-pressure oil enters the drive lower chamber through the one-way valve on the outside of the extension block, through the fan-shaped annular groove 20 on the valve sleeve, and the one-way oil inlet 21, thus enabling the pneumatic valve piston 7 to fall back normally.

[0036] The worm gear 10 is rotated by the worm 11 driven by the motor, and the rotary valve sleeve 8 is connected by a keyway, realizing the switching between the lift control oil hole 23 on the valve sleeve 8 and the oil passage on the left leading to the lower buffer chamber. Figure 4 As shown, this changes the position where the valve piston 7 completely covers the oil hole during its maximum lift, thus achieving lift change. During the lift change process, to ensure normal oil intake into the lower drive chamber, the corresponding position of the valve sleeve is machined as follows... Figure 13 The fan-shaped annular groove 20 and the one-way oil inlet 21.

[0037] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. An electro-hydraulic variable pneumatic actuator for achieving seat cushioning, characterized in that: It includes an upper drive chamber, a middle drive chamber, a lower drive chamber, an upper buffer chamber, a middle buffer chamber, and a lower buffer chamber. The upper drive chamber is formed by the cylinder body (1), the upper end face of the valve sleeve (8), and the air valve piston (7). The middle drive chamber is formed by the inner surface of the valve sleeve (8) and the upper end of the air valve piston (7). The lower drive chamber is formed by the lower end of the air valve piston (7), the inner surface of the valve sleeve (8), and the upper end face of the cylinder head (12). The upper buffer chamber is formed by the cylinder body (1) and the upper end face of the buffer piston (2). The buffer cavity is formed by the inner annular groove (17) and the side of the buffer piston (2). The buffer lower cavity is formed by the cylinder body (1) and the lower end face of the buffer piston (2). The cylinder body (1) is provided with a medium-pressure oil port (16) in the buffer lower cavity. The medium-pressure oil port (16) can be blocked by the buffer piston (2). An oblique oil passage (15) is provided on the cylinder body (1). The oblique oil passage (15) is connected to the medium-pressure oil port (16). The medium-pressure oil port (16) and the drive lower cavity are both connected to the buffer lower cavity. The cylinder body (1) has a drive inner ring groove (18) and a control port (19) in the drive middle cavity. The control port (19) is connected to the reversing valve (24) through a pipeline. The reversing valve (24) is connected to the low-pressure oil rail (25) and the high-pressure oil rail (26). The valve sleeve (8) has a radial oil port (22) in the drive middle cavity. The radial oil port (22) is connected to the drive inner ring groove (18). The valve sleeve (8) has multiple lift controls in the drive lower cavity. Oil hole (23), the plurality of lift control oil holes (23) are arranged axially along the valve sleeve (8), the lift control oil hole (23) can be blocked by the air valve piston (7), a first one-way valve (13) is provided between the connecting passage of the upper drive chamber and the upper buffer chamber and the connecting passage of the middle drive chamber and the middle buffer chamber, a second one-way valve (14) is provided between the lower drive chamber and the lower buffer chamber, a buffer groove is provided on the buffer piston (2), and a buffer spring (4) is provided below the buffer piston (2).

2. The electro-hydraulic variable pneumatic actuator for achieving seating buffering according to claim 1, characterized in that: The valve sleeve (8) is provided with a fan-shaped annular groove (20) and a one-way oil inlet (21), which are connected to the lower drive chamber.

3. The electro-hydraulic variable pneumatic actuator for achieving seating buffering according to claim 2, characterized in that: An extension block (9) is provided on the outside of the cylinder body (1). A third check valve is provided on the extension block (9). The third check valve is connected to the medium pressure oil rail (27). After passing through the third check valve, the medium pressure oil enters the drive lower chamber through the fan-shaped annular groove (20) and the one-way oil inlet (21).

4. The electro-hydraulic variable pneumatic actuator for achieving seating buffering according to claim 1, characterized in that: The valve sleeve (8) is connected to the worm wheel (10), and the worm wheel (10) meshes with the worm (11).

5. The electro-hydraulic variable pneumatic actuator for achieving seat cushioning according to claim 1, characterized in that: A separation block (3) is provided on the cylinder (1), and an adjustment knob (5) is provided at the bottom of the separation block (3). The adjustment knob (5) is in contact with one end of the buffer spring (4).

6. The electro-hydraulic variable pneumatic actuator for achieving seating buffering according to claim 5, characterized in that: The bottom of the separation block (3) is provided with a sealing block (6), and the adjustment knob (5) is provided on the sealing block (6).

7. An electro-hydraulic variable pneumatic actuator for achieving seating buffering according to claim 1, characterized in that: The buffer groove has a stepped groove structure, and the flow area of ​​the stepped groove gradually decreases from top to bottom.

8. The electro-hydraulic variable pneumatic actuator for achieving seating buffering according to claim 1, characterized in that: The first check valve (13) and the second check valve (14) are both built-in structures, and the flow rate of the first check valve (13) is greater than that of the second check valve (14).

9. An execution method for an electro-hydraulic variable pneumatic actuator as described in any one of claims 1-8, characterized in that: When the system working valve is open, the reversing valve (24) connects to the high-pressure oil rail (26). The high-pressure oil flows from the lift control oil hole (23) and the drive inner ring groove (18) to the drive middle chamber, and enters the drive upper chamber and buffer upper chamber through the first check valve (13). The high-pressure oil pushes the air valve piston (7) and the buffer piston (2) downward. When the buffer piston (2) moves downward, the hydraulic oil in the buffer lower chamber is connected to the medium-pressure oil rail (27) through the medium-pressure oil port (16). When the air valve piston (7) moves downward, the hydraulic oil in the drive lower chamber enters the inclined oil passage (15) through the lift control oil hole (23), and enters the buffer lower chamber through the second check valve (14), and finally connects to the medium-pressure oil rail (27). When the lower edge of the buffer piston (2) moves downward to completely cover the medium-pressure oil port (16), the buffer piston (2) stops moving. When the lower edge of the air valve piston (7) moves downward to completely block the lift control oil hole (23), the air valve piston (7) stops moving. When the valve begins to fall back, the reversing valve (24) connects the low-pressure oil rail (25). Due to the influence of the first check valve (13), the high-pressure oil in the upper driving chamber and the high-pressure oil in the upper buffer chamber can only be connected to the control oil port (19) corresponding to the driving middle chamber through the buffer groove on the buffer piston (2). Therefore, when the valve just begins to fall back, the upper buffer chamber is in a high-pressure state. At this time, the buffer piston (2) is in the lower position. As the hydraulic oil flows through the buffer groove to the control oil port (19), the oil pressure in the upper buffer chamber begins to drop. Under the action of the buffer spring (4) and the medium-pressure oil, the buffer piston (2) is pushed upward, which reduces the flow area of ​​the buffer groove and thus limits the outflow speed of the high-pressure oil, thereby reducing the sitting speed and achieving the sitting buffer effect.

10. The execution method of an electro-hydraulic variable gas distribution actuator according to claim 9, characterized in that: The worm gear (10) is driven by the motor to rotate the worm wheel (10). The worm wheel (10) is connected to the rotary valve sleeve (8) through the keyway, so that the lift control oil hole (23) on the valve sleeve (8) is switched with the oil passage on the left side leading to the lower buffer chamber. This changes the position of the gas valve piston (7) when it is at its maximum lift, thus realizing the lift change.

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