High-pressure-resistant piston type hydraulic oil cylinder with multi-stage buffer structure

Abstract

The invention discloses a high-pressure-resistant piston type hydraulic oil cylinder with a multi-stage buffering structure, and relates to the technical field of hydraulic oil cylinders, the high-pressure-resistant piston type hydraulic oil cylinder comprises a cylinder body, a piston rod, a piston, a rotating sleeve, a buffering sleeve, a buffering cavity, an oil outlet gap, a guide buffering groove and a matching part, and when the rotating sleeve is inserted into the buffering cavity, the matching part is matched with the guide buffering groove; and the rotating sleeve can be driven to rotate under the guide of the guide buffer groove, so that resistance buffer is formed for the axial movement of the piston rod. According to the hydraulic damper, the rotating sleeve is inserted into the buffering cavity to extrude oil, the oil is discharged from the oil outlet gap, and first-stage hydraulic damping is formed; secondly, linear motion of the piston rod is converted into rotary motion of the rotary sleeve through motion of the rolling part in the spiral buffer groove, and second-stage mechanical damping is formed through rotary resistance; and finally, at the tail section of the stroke, the opening degree of the oil outlet gap is adjusted through the floating part, the back pressure is further increased, and third-stage buffering is formed.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder technology, specifically to a high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure. Background Technology

[0002] A hydraulic cylinder is a hydraulic actuator that converts hydraulic energy into mechanical energy to perform linear reciprocating motion (or oscillating motion). It has a simple structure and reliable operation. When used to achieve reciprocating motion, it eliminates the need for a speed reduction device, eliminates transmission backlash, and provides smooth movement. Therefore, it is widely used in the hydraulic systems of various machines.

[0003] In existing technology, hydraulic cylinders used for lifting heavy objects typically have a buffer mechanism installed inside the cylinder to withstand axial loads. When lowering a heavy object, as the piston rod retracts to its final section, the buffer plunger inserts into the buffer hole, generating back pressure by reducing the cross-sectional area of ​​the return oil channel, thereby forcing the piston to decelerate and achieving mechanical buffering.

[0004] However, the above structure suffers from the following problems during long-term use: due to frequent friction and impact between the buffer plunger and the buffer hole, the buffer plunger is prone to wear. Once the plunger wears, the clearance between it and the buffer hole increases, leading to increased oil leakage and a decrease in back pressure. This directly results in a significant reduction in the buffering effect at the end of the piston rod, easily causing impact noise and even damaging the equipment. Therefore, there is an urgent need for a hydraulic cylinder structure that can compensate for wear clearance or has redundant buffering function. Summary of the Invention

[0005] The purpose of this invention is to provide a high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure, comprising a cylinder body and a piston rod slidably disposed within the cylinder body, one end of the piston rod being connected to a piston, and one end of the piston rod extending into the cylinder body being coaxially connected to a rotatable rotating sleeve, and a buffer sleeve being provided at the bottom of the cylinder body; The buffer sleeve has a buffer cavity for the insertion of the rotating sleeve. The side wall of the buffer sleeve has multiple oil outlet slits arranged in an axial array that communicate with the buffer cavity. The inner wall of the buffer cavity is provided with a guide buffer groove. The rotating sleeve is provided with a mating part. When the rotating sleeve is inserted into the buffer cavity, the mating part engages with the guide buffer groove and can drive the rotating sleeve to rotate under the guidance of the guide buffer groove, so as to form a resistance buffer for the axial movement of the piston rod.

[0007] Furthermore, the piston rod has a mounting sleeve at one end that extends into the cylinder, and the rotating sleeve is rotatably sleeved to the outside of the mounting sleeve via a bearing. The inner wall of the rotating sleeve has an abutment block. The outer wall of the mounting sleeve is provided with an arc-shaped groove, the abutment block extends into the arc-shaped groove, and a spring is provided in the arc-shaped groove. The spring elastically abuts the abutment block to provide a restoring force for the rotation of the rotating sleeve.

[0008] Furthermore, the mating part is a rolling part rotatably disposed at the end of the rotating sleeve, and the guide buffer groove includes a straight buffer groove and a spiral buffer groove that are connected to each other. The rolling part can slide into the straight section buffer groove and then into the spiral buffer groove. When the rolling part slides in the spiral buffer groove, it drives the rotating sleeve to rotate.

[0009] Furthermore, the rolling part is a sphere, and a spherical groove is provided at the end of the rotating sleeve away from the piston. The rolling part is rotatably embedded in the spherical groove, and the cross-sectional diameters of the straight buffer groove and the spiral buffer groove are both matched with the spherical diameter of the rolling part.

[0010] Furthermore, the straight section buffer groove is located on the side of the spiral buffer groove near the opening of the buffer cavity, and the end of the straight section buffer groove away from the spiral buffer groove is provided with a rounded chamfer.

[0011] 6. A high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure according to claim 1, characterized in that the buffer sleeve is provided with a floating adjustment mechanism for adjusting the opening of the oil outlet gap.

[0012] Furthermore, the floating adjustment mechanism includes a sliding part and a floating part, and the buffer sleeve has an installation cavity at the end away from the buffer cavity; The sliding part is slidably disposed in the mounting cavity, and the floating part is connected to the side of the sliding part facing the buffer cavity. The periphery of the floating part is provided with an adjustment groove corresponding to the oil outlet gap. When the floating part is pressed and slides, it can change the overlapping area of ​​the adjustment groove and the oil outlet gap.

[0013] Furthermore, the floating part has multiple hollowed-out grooves on one end face facing the buffer cavity, and the hollowed-out grooves are respectively connected to the buffer cavity and the adjustment groove.

[0014] Furthermore, a return spring is provided inside the mounting cavity, which elastically abuts against the side of the sliding part away from the floating part. A locking block is provided around the sliding part, and a slot is provided on the inner wall of the mounting cavity for the locking block to slide.

[0015] Furthermore, the piston rod has a mounting sleeve at one end that extends into the cylinder. The mounting sleeve moves with the piston rod and abuts against the floating part to push the floating part to move, thereby reducing the opening of the oil outlet gap.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, the rotating sleeve is inserted into the buffer chamber to compress the oil, which is then discharged from the oil outlet gap, forming the first stage of hydraulic damping. Secondly, the movement of the rolling part within the spiral buffer groove converts the linear motion of the piston rod into the rotational motion of the rotating sleeve, utilizing rotational resistance to form the second stage of mechanical damping. Finally, at the end of the stroke, the opening of the oil outlet gap is adjusted by the floating part to further increase the back pressure, forming the third stage of buffering. This multi-stage coordination makes the buffering process smoother, avoiding the problem of a single buffer structure experiencing a sharp decline in buffering effect due to wear after long-term use. It combines the mechanisms of "mechanical rotational buffering" and "hydraulic throttling buffering," significantly improving the buffering effect and stability. 2. In this invention, even when the outer wall of the rotating sleeve wears down due to long-term friction, it can still be smoothly inserted into the buffer cavity, and the rolling part can still smoothly engage with the spiral buffer groove. The rotational resistance generated when the rolling part rolls in the spiral groove does not depend on the tight fit between the rotating sleeve and the buffer cavity wall. Therefore, even with some wear, the resistance generated by the spiral motion still exists, thus providing redundant buffering function, ensuring the service life and safety of the equipment, and possessing wear compensation function. 3. In this invention, by setting a floating adjustment mechanism (floating part, adjustment groove, oil outlet gap), the intelligent adjustment of "the resistance increases as it goes further" is realized: at the end of the piston rod retraction, the mounting sleeve pushes the floating part to move, causing the adjustment groove and the oil outlet gap to be misaligned, reducing the flow cross-sectional area; this action leads to a decrease in the amount of oil discharged in the buffer chamber and a nonlinear increase in back pressure, thereby providing greater braking force at the end of the stroke, effectively preventing impact, improving the safety of lowering heavy objects, and realizing nonlinear pressure boosting and buffering at the end of the stroke; 4. In this invention, the design of a spring and abutment block combined with an arc-shaped groove ensures that when the piston rod extends and the rotating sleeve disengages from the buffer chamber, the spring releases its elastic potential energy, driving the rotating sleeve to rotate in the opposite direction and reset. This ensures that the rolling part can accurately align with the entrance of the straight section buffer groove during the next retraction, preventing jamming. The use of rolling friction instead of the traditional sliding friction plunger structure reduces frictional losses during the buffering process. Simultaneously, the sliding part is circumferentially limited by the cooperation of the locking block and the locking groove, ensuring the alignment accuracy of the adjusting groove and the oil outlet gap, and ensuring the reliability of the adjusting mechanism's operation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of a high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure according to the present invention. Figure 2 for Figure 1 A schematic diagram showing the positional relationship of the middle section after it has been cut open; Figure 3 This is a schematic diagram showing the positional relationship between the piston rod, piston, and rotary assembly in this invention. Figure 4 for Figure 3 A schematic diagram showing the positional relationship of the middle section after it has been cut open; Figure 5 This is an exploded disassembly diagram of the piston rod, rotating sleeve, and mounting assembly in this invention. Figure 6 This is a schematic diagram showing the positional relationship between the piston, rotating sleeve, and mounting sleeve after assembly in this invention; Figure 7 for Figure 6 A schematic diagram showing the positional relationship of the middle section after it has been cut open; Figure 8 for Figure 7 A magnified schematic diagram of the positional relationship of a local structure at point A in the middle; Figure 9 This is a schematic diagram showing the positional relationship of the buffer sleeve, connecting plate, and floating part after assembly in this invention; Figure 10 for Figure 9 A schematic diagram of the positional relationships after the explosive decomposition of the structure from another perspective; Figure 11 for Figure 9 A schematic diagram showing the positional relationship of the middle section after it has been cut open; Figure 12 for Figure 11 A magnified schematic diagram of the positional relationship of the local structure at point B.

[0018] The following are explanations of the reference numerals in the figures: 1. Cylinder body; 2. Piston rod; 3. Piston; 4. Rolling part; 5. Piston; 6. Rotating sleeve; 7. Connecting shaft; 8. Buffer sleeve; 9. Oil outlet gap; 10. Connecting plate; 11. Mounting sleeve; 12. Stop nut; 13. Arc groove; 14. Spring; 15. Abutment block; 16. Straight section buffer groove; 17. Spiral buffer groove; 18. Floating part; 19. Hollow groove; 20. Adjusting groove; 21. Locking block; 22. Sliding part; 23. Return spring; 24. Piston mounting shaft; 25. Locking groove. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figures 1-12 This invention provides a technical solution: a high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure, comprising a cylinder body 1 and a piston rod 2. One end of the piston rod 2, which passes through the cylinder body 1, is coaxially fixed to a piston mounting shaft 24. The outer diameter of the piston mounting shaft 24 is smaller than that of the piston rod 2. A piston 5 is sleeved around the periphery of the piston mounting shaft 24. The piston 5 slides freely around the periphery of the piston mounting shaft 24. A stop nut 12 is threadedly sleeved at the end of the piston mounting shaft 24 away from the piston rod 2. The end face of the stop nut 12 abuts against the end face of the piston 5 and is used to limit the piston 5 to the piston mounting shaft 24. Multiple sealing ring mounting grooves are provided around the periphery of the piston 5. Sealing rings 3 are installed in the sealing ring mounting grooves. A connecting shaft 7 is coaxially fixed to the end of the piston mounting shaft 24 away from the piston rod 2. The outer diameter of the connecting shaft 7 is smaller than that of the piston mounting shaft 24. Combination Figures 5 to 8 As shown, and with particular attention to 8, a mounting sleeve 11 is fixedly fitted around the periphery of the connecting shaft 7. A rotating sleeve 6 is rotatably fitted around the periphery of the mounting sleeve 11 via a mounting bearing. The axial length of the rotating sleeve 6 is greater than its outer diameter. Furthermore, the end face of the mounting sleeve 11 abuts against the end face of the stop nut 12. Two spherical grooves are formed at the end of the rotating sleeve 6 away from the piston 3. Rolling parts 4 are rotatably embedded in the spherical grooves and can rotate freely within them. The other two rolling parts 4 are symmetrically arranged along the axial direction of the rotating sleeve 6. Additionally, an arc-shaped groove 13 is formed around the periphery of the mounting sleeve 11, and the arc center of the arc groove 13 is aligned with the stop nut 12. The axial alignment of the mounting sleeve 11 is such that the inner wall of the rotating sleeve 6 is fixed with an abutment block 15, which engages in the arc groove 13. When the rotating sleeve 6 rotates on the periphery of the mounting sleeve 11, the abutment block 15 also slides around the axis of the mounting sleeve 11 in the arc groove 13, and the movement trajectory is arc-shaped. An arc-shaped spring 14 is installed in the arc groove 13. The two ends of the spring 14 in the direction of the elastic force abut against the inner wall of one side of the arc groove 13 and the abutment block 15, respectively. The spring 14 is used to generate an elastic abutment force on the movement of the abutment block 15 in the arc groove 13 and can drive the abutment block 15 to move in the opposite direction in the arc groove 13. Combination Figures 1 to 12 As shown, and please refer to the following: Figures 9 to 12A connecting plate 10 is installed in the inner cavity of the cylinder tail end of the cylinder body 1. A buffer sleeve 8 is coaxially fixed to the end face of the connecting plate 10 facing the piston rod 2. The buffer sleeve 8 is coaxial with the cylinder body 1 and / or the piston rod 2. A buffer cavity in the form of a blind hole is opened coaxially on the end face of the buffer sleeve 8 facing the piston rod 2. The inner diameter of the buffer cavity matches the outer diameter of the rotating sleeve 6. When the piston rod 2 moves toward the cylinder tail end of the cylinder body 1, the rotating sleeve 6 can be inserted into the buffer cavity. The rotating sleeve 6 is in sliding fit with the inner wall of the buffer cavity. Two guide buffer grooves are opened on the inner wall of the buffer cavity. The guide buffer grooves are arranged in an array along the axial direction of the buffer sleeve 8. From near to far away in the direction away from the piston rod 2, they include a straight buffer groove 16 and a spiral buffer groove 17. The straight buffer groove 16 and the spiral buffer groove 17 are connected end to end and pass through each other. In addition, the diameter of the cross section of the straight buffer groove 16 and the spiral buffer groove 17 is the same as the ball diameter of the rolling part 4. When piston 5 moves toward the tail end of cylinder 1, rotating sleeve 6 will engage with the buffer chamber, and rolling part 4 will engage with the straight buffer groove 16 and roll within it. As the depth of rotating sleeve 6 within the buffer chamber increases, rolling part 4 will roll from the straight buffer groove 16 to the spiral buffer groove 17. At this time, since the spiral buffer groove 17 is spiral (with a certain pitch), rolling part 4 will rotate along the spiral direction of the spiral buffer groove 17, driving rotating sleeve 6 to rotate. Due to the resistance of the spiral buffer groove 17 during rotation, the rolling part 4 will be resisted from moving toward the tail end of cylinder 1. At the same time, the hydraulic oil in the cylinder tail cavity of cylinder 1 fills the buffer chamber. When the rotating sleeve 6 is inserted into the buffer cavity, as the piston rod 2 moves toward the tail end of the cylinder body 1, the rotating sleeve 6 will exert a squeezing force on the hydraulic oil in the buffer cavity. In addition, the wall surface of the buffer sleeve 8 is provided with multiple oil outlet gaps 9. The width of the oil outlet gaps 9 is no more than 2mm, and the oil outlet gaps 9 are arranged in an array along the axial direction of the buffer sleeve 8. The oil outlet gaps 9 are in communication with the inner cavity of the buffer cavity. When the hydraulic oil in the buffer cavity is squeezed, the hydraulic oil will escape from the oil outlet gaps 9. In this way, the hydraulic oil will generate resistance to the movement of the rotating sleeve 6, so that the piston rod 2 will generate resistance when moving toward the tail end of the cylinder body 1. In addition, with the rolling part 4 rolling in the guide buffer groove, the movement of the piston rod 2 is damped and buffered. Furthermore, when the rolling part 4 rolls within the spiral buffer groove 17, it drives the rotating sleeve 6 to rotate. The rotation of the rotating sleeve 6 compresses the abutment block 15 against the spring 14, causing the spring 14 to accumulate elastic potential energy. When the rolling part 4 rolls from the spiral buffer groove 17 into the straight buffer groove 16, the abutment block 15 moves in the opposite direction. After the rotating sleeve 6 disengages from the buffer cavity, due to the elastic abutment force of the spring 14 against the abutment block 15, the side wall of the abutment block 15 facing away from the spring 14 and the arc... The inner walls of the shaped groove 13 abut against each other, so that the abutting block 15 will not move on its own in the shaped groove 13, and thus the rotating sleeve 6 will not rotate on its own. This allows the rolling part 4 to smoothly engage in the straight section buffer groove 16 when the piston rod 2 repeatedly moves towards the cylinder tail end of the cylinder body 1. In addition, the opening of the straight section buffer groove 16 away from the spiral buffer groove 17 is provided with a rounded chamfer. The purpose of the rounded chamfer is to prevent the rolling part 4 from colliding with the opening of the straight section buffer groove 16 when it engages in the straight section buffer groove 16. Combination Figures 1 to 12 As shown, and please refer to the following: Figures 9 to 12 The buffer sleeve 8 has a blind hole-shaped mounting cavity coaxially formed at one end relative to the buffer cavity. A sliding part 22 is coaxially engaged within the mounting cavity, allowing it to slide freely along the axial direction of the buffer sleeve 8. A floating part 18 is coaxially fixed to the end of the sliding part 22 facing the buffer cavity. A sliding hole is provided inside the buffer sleeve 8 for the floating part 18 to pass through freely. The floating part 18 can slide freely within the sliding hole. Multiple hollow grooves 19 are formed on the end face of the floating part 18 facing the piston rod 2, and an adjustment groove 20 is formed around the periphery of the floating part 18 that matches the oil outlet gap 9. The contour of the adjustment groove 20 matches the contour of the oil outlet gap 9, and when the end face of the sliding part 22 is aligned with the piston rod 2... When the inner end faces of the mounting cavity abut each other, the oil outlet gap 9 and the adjusting groove 20 are in a one-to-one correspondence and connected state. The hollow groove 19 is connected to the buffer cavity and the adjusting groove 20, so that the hydraulic oil in the buffer cavity can be discharged through the hollow groove 19, the adjusting groove 20 and the oil outlet gap 9. When the floating part 18 moves towards the connecting plate 10, the adjusting groove 20 and the oil outlet gap 9 will be misaligned, and the connection range between the adjusting groove 20 and the oil outlet gap 9 will be reduced. This will slow down the oil output of the hydraulic oil in the buffer cavity, and thus increase the back pressure resistance on the piston rod 2. This will increase the back pressure when the piston rod 2 moves towards the cylinder tail end of the cylinder body 1, thereby improving the buffering effect on the piston rod 2. Combination Figures 9 to 12 As shown, and please refer to the following: Figure 12A return spring 23 is installed inside the mounting cavity. The two ends of the return spring 23 elastically abut against the sliding part 22 and the inner wall of the cylinder tail cavity of the cylinder body 1, respectively. When the floating part 18 moves away from the piston rod 2, the sliding part 22 will compress the return spring 23, thereby causing the return spring 23 to accumulate elastic potential energy. When the rotating sleeve 6 enters the buffer cavity, the shaft end face of the mounting sleeve 11 will gradually approach the end of the floating part 18 away from the sliding part 22. When the rolling part 4 rolls in the spiral buffer groove 17, the shaft end face of the mounting sleeve 11 will abut against the end face of the floating part 18. As the mounting sleeve 11 moves, the floating part 18 will move away from the piston rod 2, and continuously cause the sliding part 22 to compress the return spring 23. At the same time, the communication range between the adjusting groove 20 and the oil outlet gap 9 will gradually decrease, thereby reducing the oil output in the buffer cavity and increasing the back pressure resistance of the piston rod 2 moving towards the cylinder tail end of the cylinder body 1.

[0021] Working principle of the invention: As the piston rod 2 moves toward the tail end of the cylinder body 1, the rotating sleeve 6 gradually approaches the buffer chamber. As the piston rod 2 continues to move, the rotating sleeve 6 enters the buffer chamber and exerts pressure on the hydraulic oil in the buffer chamber. In addition, the rolling part 4 will be engaged in the straight section buffer groove 16. At this time, the hydraulic oil in the buffer chamber will be discharged in sequence through the hollow groove 19, the adjusting groove 20, and the oil outlet gap 9, and will generate resistance on the rotating sleeve 6. This makes the piston rod 2 have back pressure resistance when it moves toward the tail end of the cylinder body 1. As the rotating sleeve 6 continues to move within the buffer cavity, the rolling part 4 will roll from the straight section buffer groove 16 to the spiral buffer groove 17. At this time, when the rolling part 4 rolls in the spiral buffer groove 17, it will resist the axial movement of the piston rod 2, thus avoiding the phenomenon of reduced back pressure when the peripheral edge of the rotating sleeve 6 is worn, or in other words, it can improve the phenomenon of reduced back pressure. In addition, when the rolling part 4 rolls in the spiral buffer groove 17, the end face of the mounting sleeve 11 will abut against the end face of the floating part 18, and as the piston rod 2 continues to move, the floating part 18 will move towards the connecting plate 10. When the floating part 18 moves toward the connecting plate 10, it will reduce the communication range between the adjusting groove 20 and the oil outlet gap 9, thereby reducing the amount of hydraulic oil discharged in the buffer chamber. At the same time, the sliding part 22 will generate a compressive force on the return spring 23, and the return spring 23 will begin to accumulate elastic potential energy. When the amount of oil discharged in the buffer chamber decreases, the back pressure increases. As a result, the back pressure can increase non-linearly at the end of the process when the piston rod 2 retracts into the cylinder 1, thereby improving the buffering effect on the piston rod 2. When the piston rod 2 extends out of the cylinder body 1, the resistance force of the mounting sleeve 11 on the floating part 18 decreases, thereby releasing the elastic potential energy of the return spring 23, which in turn drives the sliding part 22 to move in the direction of the piston rod 2, and increases the communication range between the opening of the adjusting groove 20 and the oil outlet gap 9. In addition, multiple locking blocks 21 are fixedly connected to the periphery of the sliding part 22, and multiple locking grooves 25 are opened in the inner wall of the mounting cavity. The locking blocks 21 and the locking grooves 25 are in sliding fit, thereby limiting the sliding part 22 circumferentially and preventing the adjusting groove 20 and the oil outlet gap 9 from being misaligned.

[0022] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure, comprising a cylinder body (1) and a piston rod (2) slidably disposed within the cylinder body (1), wherein one end of the piston rod (2) is connected to a piston (5), characterized in that, The piston rod (2) is coaxially connected to a rotatable rotating sleeve (6) at one end of the cylinder (1), and a buffer sleeve (8) is provided at the bottom of the cylinder (1). The buffer sleeve (8) has a buffer cavity for the insertion of the rotating sleeve (6). The side wall of the buffer sleeve (8) has multiple oil outlet gaps (9) connected to the buffer cavity in an axial array. The inner wall of the buffer cavity is provided with a guide buffer groove. The rotating sleeve (6) is provided with a mating part. When the rotating sleeve (6) is inserted into the buffer cavity, the mating part cooperates with the guide buffer groove and can drive the rotating sleeve (6) to rotate under the guidance of the guide buffer groove, so as to form a resistance buffer for the axial movement of the piston rod (2).

2. The high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure according to claim 1, characterized in that, The piston rod (2) is provided with a mounting sleeve (11) at one end that extends into the cylinder (1). The rotating sleeve (6) is rotatably sleeved to the outside of the mounting sleeve (11) through a bearing. The inner wall of the rotating sleeve (6) is provided with an abutment block (15). The outer wall of the mounting sleeve (11) is provided with an arc-shaped groove (13), the abutment block (15) extends into the arc-shaped groove (13), and a spring (14) is provided in the arc-shaped groove (13). The spring (14) elastically abuts against the abutment block (15) to provide a restoring force for the rotation of the rotating sleeve (6).

3. A high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure according to claim 1, characterized in that, The mating part is a rolling part (4) rotatably disposed at the end of the rotating sleeve (6), and the guide buffer groove includes a straight buffer groove (16) and a spiral buffer groove (17) that are connected to each other. The rolling part (4) can slide into the straight section buffer groove (16) and then into the spiral buffer groove (17). When the rolling part (4) slides in the spiral buffer groove (17), it drives the rotating sleeve (6) to rotate.

4. A high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure according to claim 3, characterized in that, The rolling part (4) is a sphere, and the rotating sleeve (6) has a spherical groove at one end away from the piston (5). The rolling part (4) is rotatably embedded in the spherical groove. The cross-sectional diameters of the straight buffer groove (16) and the spiral buffer groove (17) are matched with the sphere diameter of the rolling part (4).

5. A high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure according to claim 3, characterized in that, The straight buffer groove (16) is located on the side of the spiral buffer groove (17) near the opening of the buffer cavity, and the end of the straight buffer groove (16) away from the spiral buffer groove (17) is provided with a rounded chamfer.

6. A high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure according to claim 1, characterized in that, The buffer sleeve (8) is provided with a floating adjustment mechanism for adjusting the opening of the oil outlet gap (9).

7. A high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure according to claim 6, characterized in that, The floating adjustment mechanism includes a sliding part (22) and a floating part (18), and the buffer sleeve (8) has an installation cavity at one end away from the buffer cavity; The sliding part (22) is slidably disposed in the mounting cavity, and the floating part (18) is connected to the side of the sliding part (22) facing the buffer cavity. The periphery of the floating part (18) is provided with an adjustment groove (20) corresponding to the oil outlet gap (9). When the floating part (18) is pressed and slids, it can change the overlapping area of ​​the adjustment groove (20) and the oil outlet gap (9).

8. A high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure according to claim 7, characterized in that, The floating part (18) has multiple hollowed-out grooves (19) on one end face facing the buffer cavity. The hollowed-out grooves (19) are respectively connected to the buffer cavity and the adjustment groove (20).

9. A high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure according to claim 7, characterized in that, The mounting cavity is provided with a reset spring (23), which elastically abuts against the side of the sliding part (22) away from the floating part (18). The periphery of the sliding part (22) is provided with a locking block (21), and the inner wall of the mounting cavity is provided with a locking groove (25) for the locking block (21) to slide.

10. A high-pressure resistant piston hydraulic cylinder with a multi-stage buffer structure according to claim 7, characterized in that, The piston rod (2) has an installation sleeve (11) at one end that extends into the cylinder (1). The installation sleeve (11) moves with the piston rod (2) and can abut against the floating part (18) to push the floating part (18) to move, thereby reducing the opening of the oil outlet gap (9).

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