Hydraulic cylinder with a buffer structure

Abstract

The present application relates to hydraulic cylinder technical field, specifically is related to a kind of hydraulic cylinder with buffer structure, including cylinder barrel, the both ends of cylinder barrel are respectively fixed with end cover, still including piston, main buffer component, bottom inner ring and auxiliary buffer rod, piston is installed in the inside of cylinder barrel, including piston rod, the one end of piston rod is installed with piston head, main buffer component is installed in the one side of piston head, including main buffer rod, bottom inner ring is installed in the inner wall of end cover close to one end of main buffer component, and with end cover and form integrated structure, the middle part of bottom inner ring one side is equipped with oil guide hole, the inner wall of oil guide hole is equipped with several small through holes, bottom inner ring is distributed with several auxiliary oil holes around oil guide hole, the surface of piston head is distributed with several auxiliary buffer rods with main buffer rod as pivot equiangularly around oil guide hole. The present application solves the deficiency of hydraulic cylinder in fast buffering response, smooth buffering transition and controllable buffering effect, improves the working efficiency and control accuracy of oil cylinder.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder technology, and more specifically to a hydraulic cylinder with a buffer structure. Background Technology

[0002] Hydraulic cylinder technology primarily relies on the incompressibility and fluidity of hydraulic oil. A hydraulic pump generates pressurized oil, which drives the piston rod within the cylinder in a reciprocating motion, thus transmitting and converting force. Hydraulic cylinder technology with a buffer structure mainly uses specific buffer devices inside the cylinder to slow the piston's speed at the end of its stroke, thereby reducing impact and noise. This technology typically includes key components such as buffer valves and buffer sleeves, which slow the piston's movement speed near the end of its stroke through throttling and damping to achieve a buffering effect. Existing hydraulic cylinder end-of-stroke buffer devices are usually designed as throttling and damping structures. Throttling and damping consume and absorb the piston's impact energy. The magnitude of the impact load generated during the buffering process is directly proportional to the piston's speed. If the piston's speed is high, the peak value of the impact load generated during the end-of-stroke buffering process will be very large, which can also damage the cylinder.

[0003] Chinese Patent Publication No. CN111425484A discloses a hydraulic cylinder end-buffering device, including a right end cover, a cylinder barrel, a one-way valve, a piston buffer cone, a piston, a piston rod, and a relief valve. This invention, through innovative structural design, proposes to install a relief valve in the right end cover and a one-way valve in the piston buffer cone. On the one hand, this enhances the consumption and absorption of impact energy during the end-buffering process of the hydraulic cylinder; on the other hand, it further limits the peak value of the impact load during the end-buffering process, fully ensuring the safety of the hydraulic cylinder during operation. Simultaneously, it ensures the initial speed of the piston's reverse movement, improving the working efficiency of the hydraulic cylinder. This hydraulic cylinder end-buffering device can also be applied to hydraulic dampers and hydraulic buffers in addition to hydraulic cylinders, showing broad application prospects.

[0004] However, existing hydraulic cylinders with buffer structures mostly use a single buffer structure. The time from the start of buffering by the buffer rod to the complete stop of the piston is relatively long, which may reduce the working efficiency of the entire hydraulic system. Moreover, a single buffer structure may generate high pulse pressure during the buffering process, which may not only damage the internal components of the hydraulic cylinder, but also cause instability to the entire hydraulic system. At the same time, a single buffer structure may not be able to provide a smooth buffering effect, especially during high-speed movement or load changes, which can easily lead to sudden piston stop or mechanical collision, thereby damaging the hydraulic cylinder. In addition, existing hydraulic cylinders lack auxiliary buffer rods, auxiliary oil holes, and magnetic sleeves, which cannot form a multi-stage buffering effect, limiting the adaptability and flexibility of the hydraulic cylinder under different working conditions. Summary of the Invention

[0005] To address the aforementioned issues, a hydraulic cylinder with a buffer structure is provided. By adding auxiliary buffer structures and magnetic buffer components, the shortcomings of the hydraulic cylinder in terms of rapid buffer response, smooth buffer transition, and controllable buffer effect are solved, thereby improving the working efficiency and control accuracy of the cylinder.

[0006] To address the problems of existing technologies, this invention provides a hydraulic cylinder with a buffer structure, including a cylinder barrel, end caps fixed at both ends of the cylinder barrel, a connecting rod connecting the two end caps, a piston, a main buffer assembly, a bottom inner ring, and auxiliary buffer rods. The piston is installed inside the cylinder barrel and includes a piston rod, with a piston head mounted at one end of the piston rod. The main buffer assembly is installed on one side of the piston head and includes a main buffer rod, which provides the main buffering effect when the piston head reaches the end of its stroke. The bottom inner ring is installed on the inner wall of the end cap near the main buffer assembly and forms an integral structure with the end cap. An oil guide hole is provided in the middle of one side of the bottom inner ring, and the inner wall of the oil guide hole has several small through holes for guiding hydraulic oil to flow towards the external oil pump. Several auxiliary oil holes are evenly distributed around the oil guide hole on the bottom inner ring. Several auxiliary buffer rods are evenly distributed around the surface of the piston head with the main buffer rod as the axis, and the auxiliary oil holes and auxiliary buffer rods are compatible with each other.

[0007] Preferably, the lengths of the auxiliary buffer rods are different and gradually decrease from one end of the piston head to the other end of the piston head radially. The number of auxiliary buffer rods is the same as the number of auxiliary oil holes and they correspond one-to-one.

[0008] Preferably, the surface of the main buffer rod is evenly distributed with several drainage grooves to provide variable throttling for the hydraulic oil, and the cross-sectional structure of the drainage grooves is two opposing triangular structures.

[0009] Preferably, the bottom inner ring is provided with an end groove at the edge of the oil guide hole, and a magnetic buffer assembly is installed in the end groove. The magnetic buffer assembly includes a magnetic sleeve that is adapted to the inner wall of the oil guide hole. A magnetic ring is also installed on the piston head. The magnetic ring is sleeved on the main buffer rod and is flush with the surface of the piston head. The magnetic poles on the side of the magnetic ring opposite to those on the magnetic sleeve are opposite.

[0010] Preferably, the surface of the magnetic sleeve is provided with a number of through-holes for draining oil. The number of through-holes is the same as the number of small through holes on the inner wall of the oil guide hole. The size of the through-holes is smaller than the size of the small through holes. The magnetic sleeve is connected to the bottom inner ring by a return spring.

[0011] Preferably, an oil storage chamber is provided inside the bottom inner ring, parallel to the oil guide hole, and the oil storage chamber is interconnected with the small through hole and the auxiliary oil hole.

[0012] Preferably, one side of the oil storage tank is connected to an inlet / outlet oil pipe, which is connected to the oil pump of the hydraulic cylinder. A buffer valve is installed on the inlet / outlet oil pipe to regulate the flow rate of the hydraulic oil.

[0013] Preferably, a top inner ring is fixed to the inner wall of the end cap opposite the bottom inner ring. The top inner ring has a through working end hole in the middle of its surface for the piston rod to pass through. A buffer sleeve is installed on the side of the piston head near the top inner ring. The buffer sleeve is fitted onto the piston rod and forms an integral structure with the piston head. Except for the working end hole, the structure of the top inner ring is the same as that of the bottom inner ring. The surface of the buffer sleeve is also provided with drainage grooves that are the same as those on the surface of the main buffer rod. Several auxiliary buffer rods are also evenly distributed on the surface of the piston head around the buffer sleeve. The top inner ring and the piston head are matched to the side of the buffer sleeve.

[0014] Preferably, a flow-blocking ring is fixed to the inner wall of the working end hole to prevent hydraulic oil from overflowing along the piston rod to the outside of the end cover.

[0015] Preferably, a sealing groove is provided around the piston head, and a sealing ring is installed in the sealing groove.

[0016] The advantages of this invention compared to the prior art are:

[0017] 1. This invention incorporates an auxiliary buffer rod and an auxiliary oil hole, reducing the time from the start of buffering by the main buffer rod to the stop of piston movement, thereby improving the working efficiency of the hydraulic cylinder; it also reduces the high pulse pressure generated by a single main buffer rod during the buffering process, making the buffering process smoother, protecting the hydraulic cylinder from damage, and reducing potential hazards caused by unstable buffering during operation of the main buffer rod.

[0018] 2. This invention adds a magnetic sleeve and a magnetic ring. Before the main buffer rod enters the oil guide hole, the magnetic ring acts on the magnetic sleeve to make it enter the oil guide hole first, reducing the hydraulic oil flow path and providing a buffering force in advance. This helps the main buffer rod to disperse part of the buffering force, making the buffering effect of the hydraulic cylinder more stable and easier to control precisely.

[0019] 3. The present invention provides a drainage groove on the surface of the main buffer rod and provides an oil reservoir, inlet and outlet oil pipes and a buffer valve. The drainage groove mainly provides variable throttling to achieve uniform and smooth braking of the moving parts; while the buffer valve adjusts the flow speed of the hydraulic oil to slow down the movement speed of the piston, thereby avoiding mechanical collisions and improving the movement accuracy of the piston so that it can reach the predetermined position more accurately. Attached Figure Description

[0020] Figure 1 This is a three-dimensional diagram of a hydraulic cylinder with a buffer structure.

[0021] Figure 2This is a front view of a hydraulic cylinder with a buffer structure.

[0022] Figure 3 This is a front view of a hydraulic cylinder with a buffer structure, specifically a cross-sectional view at point AA.

[0023] Figure 4 This is an internal structure diagram of a hydraulic cylinder with a buffer structure.

[0024] Figure 5 This is a three-dimensional view of the piston of a hydraulic cylinder with a buffer structure at the end of its stroke.

[0025] Figure 6 This is a three-dimensional view of the piston of a hydraulic cylinder with a buffer structure.

[0026] Figure 7 This is a three-dimensional view of the seal ring separating from the piston head of a hydraulic cylinder with a buffer structure.

[0027] Figure 8 This is a three-dimensional view of the bottom inner ring of a hydraulic cylinder with a buffer structure.

[0028] Figure 9 This is a left view of the bottom inner ring of a hydraulic cylinder with a buffer structure.

[0029] Figure 10 This is a perspective view of the bottom inner ring of a hydraulic cylinder with a buffer structure, specifically at point BB (left view).

[0030] Figure 11 This is an exploded view of the bottom inner ring of a hydraulic cylinder with a buffer structure.

[0031] Figure 12 This is a three-dimensional view of the top inner ring of a hydraulic cylinder with a buffer structure.

[0032] The following are the labels in the diagram: 1. Cylinder; 11. End cap; 12. Connecting rod; 2. Piston; 21. Piston rod; 22. Piston head; 23. Magnetic ring; 24. Sealing groove; 25. Sealing ring; 3. Main buffer assembly; 31. Main buffer rod; 32. Drain groove; 33. Buffer sleeve; 4. Bottom inner ring; 41. Oil guide hole; 42. Small through hole; 43. Auxiliary oil hole; 44. End groove; 45. Oil reservoir; 46. Inlet and outlet oil pipes; 47. Buffer valve; 5. Auxiliary buffer rod; 6. Magnetic buffer assembly; 61. Magnetic sleeve; 62. Oil drain hole; 63. Return spring; 7. Top inner ring; 71. Working end hole; 72. Flow choke ring. Detailed Implementation

[0033] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0034] like Figures 1-12 As shown, a hydraulic cylinder with a buffer structure includes a cylinder barrel 1, with end caps 11 fixed to both ends of the cylinder barrel 1, and a pull rod 12 connecting the two end caps 11. It also includes a piston 2, a main buffer assembly 3, a bottom inner ring 4, and an auxiliary buffer rod 5. The piston 2 is installed inside the cylinder barrel 1 and includes a piston rod 21. A piston head 22 is installed at one end of the piston rod 21. The main buffer assembly 3 is installed on one side of the piston head 22 and includes a main buffer rod 31, which provides the main buffering effect when the piston head 22 reaches the end of its stroke. The bottom inner ring 4 is installed on the inner wall of the end cap 11 near the main buffer assembly 3 and forms an integral structure with the end cap 11. The middle of one side of the bottom inner ring 4 is provided with an oil guide hole 41. The inner wall of the oil guide hole 41 is provided with several small through holes 42 for guiding hydraulic oil to flow towards the external oil pump. Several auxiliary oil holes 43 are evenly distributed around the oil guide hole 41 on the bottom inner ring 4. Several auxiliary buffer rods 5 are evenly distributed around the surface of the piston head 22 with the main buffer rod 31 as the axis. The auxiliary oil holes 43 and the auxiliary buffer rods 5 are matched.

[0035] The piston 2 and cylinder 1 form a sliding structure. One of the endpoints of the piston 2's stroke within the cylinder 1 is the bottom inner ring 4. When the piston head 22 moves toward the bottom inner ring 4, it will squeeze the hydraulic oil toward the bottom inner ring 4. Initially, the hydraulic oil can flow out of the cylinder 1 through the small through hole 42 in the oil guide hole 41 and the auxiliary oil hole 43 on the bottom inner ring 4. At this time, the piston 2's running speed is normal and is not affected by the buffering effect. When the piston 2 moves to a certain distance from the bottom inner ring 4, the main buffer rod 31 and the auxiliary buffer rod 5 will successively contact the oil guide hole 41 and the auxiliary oil hole 43, gradually reducing the channel for hydraulic oil to flow out of the cylinder 1, thus reducing the hydraulic oil flow rate and achieving the buffering effect. The auxiliary oil hole 43 is designed to add additional buffering on top of the main buffer rod 31 and the guide oil hole 41. When the hydraulic cylinder only has the main buffer rod 31 as the sole buffering structure, if the buffering effect is large, the time interval from when the main buffer rod 31 enters the guide oil hole 41 to when the piston 2 stops moving may be long, which may result in low working efficiency of the hydraulic cylinder. In addition, the main buffer rod 31 alone may generate high pulse pressure during the buffering process, which may lead to an unstable buffering process and even damage to the hydraulic cylinder. However, by adding an auxiliary buffer column and an auxiliary oil hole 43, the buffering pressure of the main buffer rod 31 can be partially borne, reducing the potential hazards caused by the unstable buffering process of the main buffer rod 31 during operation.

[0036] like Figures 3-7 As shown, the lengths of the auxiliary buffer rods 5 are all different, and they gradually decrease from one end of the piston head 22 in the radial direction to the other end of the piston head 22 in the radial direction. The number of auxiliary buffer rods 5 is the same as the number of auxiliary oil holes 43 and they correspond one-to-one.

[0037] As the piston head 22 gradually approaches the bottom inner ring 4, the auxiliary buffer rods 5 also gradually approach and contact the auxiliary oil holes 43. Since the lengths of the auxiliary buffer rods 5 are different and decrease radially along the piston head 22, they do not enter the auxiliary oil holes 43 simultaneously. Instead, they enter the auxiliary oil holes 43 one by one, from longest to shortest, according to their different lengths. Each time an auxiliary buffer rod 5 enters an auxiliary oil hole 43, the flow path of the hydraulic oil is reduced, and the buffering force increases slightly, rather than the sudden increase in buffering force that occurs when all auxiliary oil holes 43 are blocked simultaneously. This structure allows the buffering pressure to gradually and smoothly transition from small to large, making the entire buffering process gradual and improving its stability.

[0038] like Figures 4-7 As shown, the surface of the main buffer rod 31 is evenly distributed with several drainage grooves 32, which are used to provide variable throttling for hydraulic oil. The cross-sectional structure of the drainage grooves 32 is two opposing triangular structures.

[0039] The primary function of the flow-guiding groove 32 is to provide variable throttling to achieve uniform and smooth braking of the moving parts. The design of the flow-guiding groove 32 ensures that the flow cross-section through which the hydraulic oil can pass gradually decreases as the piston 2 moves. When the piston 2 approaches the end of its stroke, the reduced flow cross-section decreases the oil flow velocity, creating resistance and gradually slowing down the movement of the working parts. As the speed decreases, the buffering effect gradually strengthens due to the throttling effect of the flow-guiding groove 32. This design ensures the uniformity of the buffering effect, avoiding the problem of insufficient buffering at the end of the stroke. Due to the throttling effect of the flow-guiding groove 32, the oil experiences a certain pressure loss as it passes through, thereby reducing the pressure peak during the buffering process and protecting the cylinder and related components from damage. Because the buffering effect of the flow-guiding groove 32 is uniform and adjustable, the hydraulic cylinder can achieve precise braking at a predetermined position, improving the accuracy and reliability of the hydraulic system. Therefore, the variable throttling provided by the flow-guiding groove 32 is mainly to achieve smooth deceleration, control the deceleration rate, improve buffering performance, extend service life, and enhance the adaptability of the system.

[0040] like Figures 8-11 As shown, the bottom inner ring 4 is provided with an end slot 44 at the edge of the oil guide hole 41. A magnetic buffer assembly 6 is installed in the end slot 44. The magnetic buffer assembly 6 includes a magnetic sleeve 61, which is adapted to the inner wall of the oil guide hole 41. A magnetic ring 23 is also installed on the piston head 22. The magnetic ring 23 is sleeved on the main buffer rod 31 and is flush with the surface of the piston head 22. The magnetic poles of the magnetic ring 23 and the magnetic sleeve 61 are opposite on the opposite side.

[0041] In addition to the main buffer rod 31 and the auxiliary buffer rod 5, an extra buffer structure is provided. Based on the principle of like poles repulsion between the magnetic ring 23 and the magnetic sleeve 61, when the piston head 22 approaches the bottom inner ring 4, the magnetic ring 23 exerts a force on the magnetic sleeve 61, causing the magnetic sleeve 61 to move into the oil guide hole 41. The magnetic sleeve 61 gradually blocks the small through hole 42 before the main buffer rod 31, reducing the hydraulic oil flow path and achieving the buffering effect.

[0042] like Figures 8-11 As shown, the surface of the magnetic sleeve 61 is provided with several through-holes 62 for draining oil. The number of through-holes 62 is the same as the number of small through holes 42 on the inner wall of the oil guide hole 41. The size of the through-holes 62 is smaller than the size of the small through holes 42. The magnetic sleeve 61 is connected to the bottom inner ring 4 through a return spring 63.

[0043] When the return spring 63 is compressed to its limit by the magnetic sleeve 61, the top of the magnetic sleeve 61 is parallel to one side of the bottom inner ring 4, facilitating the piston head 22 to complete its stroke after engaging with the bottom inner ring 4. The small drain hole 62 on the magnetic sleeve 61 continues to provide a flow path for hydraulic oil when the magnetic sleeve 61 enters the guide hole 41 and the main buffer rod 31 has not yet entered the guide hole 41, although the flow rate has been significantly reduced, achieving the first step of buffering. When the main buffer rod 31 enters the guide hole 41, it further blocks the small drain hole 62 on the magnetic sleeve 61, further enhancing the buffering force. This structure further disperses the buffering pressure during the piston 2's stroke, making the buffering effect more stable and easier to control precisely. When the piston head 22 leaves the bottom inner ring 4, the return spring 63 returns the magnetic sleeve 61 to its initial position, opening the small through hole 42, allowing hydraulic oil to enter the cylinder 1 more quickly, improving the working efficiency of the hydraulic cylinder.

[0044] like Figures 8-11 As shown, an oil storage tank 45 is provided parallel to the bottom inner ring 4 below the oil guide hole 41. The oil storage tank 45 is interconnected with the small through hole 42 and the auxiliary oil hole 43.

[0045] The oil reservoir 45 is a transfer station for hydraulic oil from cylinder 1 to hydraulic cylinder pump. During the process of piston head 22 contacting bottom inner ring 4, hydraulic oil first enters oil reservoir 45 through small through hole 42 and auxiliary oil hole 43, and then enters oil pump from oil reservoir 45. Conversely, when piston head 22 is away from bottom inner ring 4, hydraulic oil enters oil reservoir 45 from oil pump, and then is distributed from oil reservoir 45 to small through hole 42 and auxiliary oil hole 43.

[0046] like Figures 8-11 As shown, an inlet / outlet oil pipe 46 is connected to one side of the oil storage tank 45. The inlet / outlet oil pipe 46 is connected to the oil pump of the hydraulic cylinder. A buffer valve 47 is installed on the inlet / outlet oil pipe 46. The buffer valve 47 is used to regulate the flow rate of the hydraulic oil.

[0047] The hydraulic oil inside cylinder 1 is connected to the hydraulic cylinder's pump via inlet / outlet pipes 46. A buffer valve 47 is installed at one end of the inlet / outlet pipes 46. The buffer valve 47 typically consists of a valve body, valve core, and spring. When hydraulic oil flows through the buffer valve 47, the valve core moves under hydraulic pressure, thus changing the flow path of the hydraulic oil and achieving buffered control of the hydraulic cylinder's movement. When piston 2 approaches the end of its stroke, a mechanical collision may occur between piston 2 and cylinder 1, potentially damaging cylinder 1 and generating noise and impact. The buffer valve 47, by adjusting the flow rate of the hydraulic oil, slows down the movement speed of piston 2, thereby preventing mechanical collisions. Slowing down the movement speed of piston 2 also helps improve its movement accuracy, allowing it to reach the predetermined position more precisely.

[0048] like Figure 3 and Figure 12 As shown, a top inner ring 7 is fixed to the inner wall of the end cap 11 opposite to the bottom inner ring 4. The top inner ring 7 has a through working end hole 71 in the middle of its surface for the piston rod 21 to pass through. A buffer sleeve 33 is installed on the side of the piston head 22 near the top inner ring 7. The buffer sleeve 33 is sleeved on the piston rod 21 and forms an integral structure with the piston head 22. Except for the working end hole 71, the structure of the top inner ring 7 is consistent with that of the bottom inner ring 4. The surface of the buffer sleeve 33 is also provided with a drainage groove 32 that is the same as the surface of the main buffer rod 31. Several auxiliary buffer rods 5 are also evenly distributed on the surface of the piston head 22 around the buffer sleeve 33. The top inner ring 7 and the piston head 22 are adapted to be located on one side of the buffer sleeve 33.

[0049] The piston 2 reciprocates bidirectionally within the cylinder 1. Therefore, a buffer structure is required not only at the bottom inner ring 4 but also at the top inner ring 7. The difference lies in the fact that a working end hole 71 for the piston rod 21 to run through is pre-drilled in the middle of the top inner ring 7. The remaining structure and buffer device are the same as those at the bottom inner ring 4 and will not be described in detail here. This structure ensures that the piston 2 is protected by a buffering effect when moving in both directions, thereby improving the service life of the hydraulic cylinder.

[0050] like Figure 3 and Figure 12 As shown, a flow-blocking ring 72 is fixed to the inner wall of the working end hole 71 to prevent hydraulic oil from overflowing from the piston rod 21 to the outside of the end cover 11.

[0051] When the piston rod 21 moves in and out along the working end hole 71, the flow-blocking ring 72 provides a tight sealing structure, preventing hydraulic oil from overflowing with the piston rod 21. At the same time, the flow-blocking ring 72 also acts as a limit, restricting the running path of the piston rod 21.

[0052] like Figure 3 , Figure 6 and Figure 7 As shown, a sealing groove 24 is provided around the piston head 22, and a sealing ring 25 is installed in the sealing groove 24.

[0053] The sealing ring 25 tightly wraps around the piston head 22, forming an effective sealing interface. This ensures that the hydraulic oil inside the hydraulic cylinder does not leak out from the gaps in the cylinder body. A qualified sealing ring 25 can ensure the stable operation of the hydraulic system and prevent pressure loss and reduced efficiency caused by hydraulic oil leakage. At the same time, good sealing performance can ensure the stable operation of the hydraulic system, improve the working efficiency of the hydraulic pump, and thus ensure the normal operation of the mechanical equipment. In addition, the sealing ring 25 can ensure that the hydraulic oil does not leak out, maintain the oil lubrication and cooling state inside the hydraulic system, thereby protecting the life and stability of hydraulic components. It can also prevent impurities from entering the hydraulic cylinder, avoiding wear on the sealing ring 25 and the piston head 22 surface, and reducing sealing performance and motion accuracy.

[0054] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A hydraulic cylinder with a buffer structure, comprising a cylinder barrel (1), with end caps (11) fixed at both ends of the cylinder barrel (1), and a pull rod (12) connected between the two end caps (11); Its features are, It also includes a piston (2), a main buffer assembly (3), a bottom inner ring (4), and an auxiliary buffer rod (5); The piston (2) is installed inside the cylinder (1) and includes a piston rod (21). A piston head (22) is installed at one end of the piston rod (21). The main buffer assembly (3) is installed on one side of the piston head (22) and includes a main buffer rod (31) for providing the main buffering effect when the piston head (22) reaches the end of its stroke. The bottom inner ring (4) is installed on the inner wall of the end cap (11) near the main buffer assembly (3) and forms an integral structure with the end cap (11); An oil guide hole (41) is provided in the middle of one side of the bottom inner ring (4), and several small through holes (42) are provided on the inner wall of the oil guide hole (41) to guide the hydraulic oil to flow towards the external oil pump. Several auxiliary oil holes (43) are evenly distributed around the oil guide hole (41) on the bottom inner ring (4); Several auxiliary buffer rods (5) are distributed at equal angles around the surface of the piston head (22) with the main buffer rod (31) as the axis; The auxiliary oil hole (43) is compatible with the auxiliary buffer rod (5); The lengths of the auxiliary buffer rods (5) are different and gradually decrease from one end of the piston head (22) in the radial direction to the other end of the piston head (22); The number of auxiliary buffer rods (5) is the same as the number of auxiliary oil holes (43) and they correspond one-to-one; The surface of the main buffer rod (31) is evenly distributed with several drainage grooves (32) for providing variable throttling for hydraulic oil; The cross-sectional structure of the drainage groove (32) is two opposing triangular structures; The bottom inner ring (4) is provided with an end slot (44) at the edge of the oil guide hole (41), and a magnetic buffer assembly (6) is installed in the end slot (44); The magnetic buffer assembly (6) includes a magnetic sleeve (61) which is adapted to the inner wall of the oil guide hole (41); A magnetic ring (23) is also installed on the piston head (22). The magnetic ring (23) is sleeved on the main buffer rod (31) and is flush with the surface of the piston head (22). The magnetic poles of the magnetic ring (23) and the magnetic sleeve (61) are opposite on the opposite side; The surface of the magnetic sleeve (61) is provided with several through-holes (62). The number of through-holes (62) is the same as the number of through holes (42) on the inner wall of the oil guide hole (41). The size of the through-holes (62) is smaller than the size of the through holes (42). The magnetic sleeve (61) is connected to the bottom inner ring (4) via a return spring (63).

2. A hydraulic cylinder with a buffer structure according to claim 1, characterized in that, An oil storage tank (45) is provided inside the bottom inner ring (4) below the oil guide hole (41) and parallel to it. The oil storage tank (45) is connected to the small through hole (42) and the auxiliary oil hole (43).

3. A hydraulic cylinder with a buffer structure according to claim 2, characterized in that, One side of the oil storage tank (45) is connected to an oil inlet / outlet pipe (46), which is connected to the oil pump of the hydraulic cylinder. A buffer valve (47) is installed on the inlet and outlet oil pipes (46). The buffer valve (47) is used to regulate the flow rate of the hydraulic oil.

4. A hydraulic cylinder with a buffer structure according to claim 1, characterized in that, A top inner ring (7) is fixed to the inner wall of the end cap (11) opposite to the bottom inner ring (4). The top inner ring (7) has a through working end hole (71) in the middle of its surface for the piston rod (21) to pass through. A buffer sleeve (33) is installed on the side of the piston head (22) near the top inner ring (7). The buffer sleeve (33) is sleeved on the piston rod (21) and forms an integral structure with the piston head (22). Except for the working end hole (71), the structure of the top inner ring (7) is the same as that of the bottom inner ring (4); The surface of the buffer sleeve (33) is also provided with the same drainage groove (32) as the surface of the main buffer rod (31), and several auxiliary buffer rods (5) are evenly distributed on the surface of the piston head (22) around the buffer sleeve (33); The top inner ring (7) is adapted to the piston head (22) on one side of the buffer sleeve (33).

5. A hydraulic cylinder with a buffer structure according to claim 4, characterized in that, A flow-blocking ring (72) is fixed to the inner wall of the working end hole (71) to prevent hydraulic oil from overflowing from the piston rod (21) to the outside of the end cover (11).

6. A hydraulic cylinder with a buffer structure according to claim 1, characterized in that, A sealing groove (24) is provided around the piston head (22), and a sealing ring (25) is installed in the sealing groove (24).

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