Hydraulic cylinder with a buffer structure

Abstract

The application relates to the technical field of hydraulic cylinders, in particular to an oil cylinder with a buffer structure, which comprises a cylinder barrel and a piston rod assembly, the piston rod assembly is inserted into the cylinder barrel and is in sliding fit with the cylinder barrel, a rod cavity oil port is arranged on the piston rod assembly, and a sealed oil cavity is arranged in the piston rod assembly; a guide sleeve is arranged between the outer cylinder barrel barrel port and the piston rod assembly; a one-way valve flow channel is arranged on the piston rod assembly, and a ball is arranged in the one-way valve flow channel; a plurality of damping holes are arranged on the piston rod assembly along the axial direction of the cylinder barrel and are in communication with the sealed oil cavity, the plurality of damping holes are sequentially matched with the guide sleeve along with the movement of the piston rod assembly, and the damping of the damping holes is changed. The application does not need to arrange an additional one-way valve structure, but directly reforms and arranges the one-way valve flow channel on the oil cylinder structure, so that the one-way valve function is realized, and the plurality of damping holes are matched, so that even the oil cylinder with compact structure can realize quick starting.

Description

Technical Field

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

[0002] In industries such as engineering machinery, mining, metallurgy, and energy, the hydraulic cylinders used are characterized by large load and high speed. In order to ensure the safety of the hydraulic cylinder and the whole machine, a buffer structure needs to be set inside the hydraulic cylinder.

[0003] Existing buffer structures typically employ buffer columns and buffer rings that are fixedly connected to the cylinder structure. However, the buffer structure creates a throttling effect when the cylinder starts, resulting in high starting pressure and slow operation, making it unsuitable for high-speed applications. To meet the requirement of rapid starting, a separate starting valve (check valve) is required inside the cylinder, which increases costs and complicates manufacturing. The check valve undoubtedly increases the structural burden, making it unsuitable for compact cylinders. Utility Model Content

[0004] The technical problem to be solved by this utility model is that the existing one-way valves used to realize the rapid start of hydraulic cylinders with buffer structures are expensive and difficult to adapt to hydraulic cylinders with compact structures.

[0005] Therefore, this utility model provides a hydraulic cylinder with a buffer structure.

[0006] The technical solution adopted by this utility model to solve its technical problem is: A hydraulic cylinder with a buffer structure includes, Cylinder, and A piston rod assembly is inserted into a cylinder and slides within the cylinder. The piston rod assembly has a rod chamber oil port and a sealed oil chamber inside the piston rod assembly. A guide sleeve is disposed between the outer cylinder opening and the piston rod assembly; A one-way valve flow channel is provided on the piston rod assembly and communicates with the oil port of the rod chamber. A ball bearing is provided inside the one-way valve flow channel. Multiple damping holes are arranged along the axial direction of the cylinder on the piston rod assembly and communicate with the sealing oil chamber. As the piston rod assembly moves, the multiple damping holes sequentially engage with the guide sleeve to change the damping at the damping hole.

[0007] Furthermore, the piston rod assembly includes a piston rod, a fixing nut, and a piston. The piston rod is inserted into the cylinder, and the piston is connected to the end of the piston rod inserted into the cylinder through the fixing nut. The one-way valve passage is disposed on the fixing nut.

[0008] Furthermore, a rod chamber is formed between the piston rod and the cylinder, and an annular channel is provided between the fixing nut and the piston rod. The annular channel communicates with the rod chamber. One end of the one-way valve flow channel communicates with the sealing oil chamber, and the other end communicates with the annular channel. The end of the one-way valve flow channel opposite to the annular channel is set as a receiving groove for accommodating the ball. The diameter of the receiving groove is larger at the end near the annular channel.

[0009] Furthermore, a rodless chamber is formed between the bottom of the cylinder and the piston, a buffer column is provided on the cylinder, an oil inlet pipe is provided inside the piston rod, the oil inlet pipe is connected to a fixing nut, and the buffer column is inserted into the oil inlet pipe.

[0010] Furthermore, a buffer ring is sleeved on the buffer post, and a gap is provided between the buffer ring and the buffer post. The buffer ring is located in the rodless cavity, and the buffer ring slides relative to the buffer post along the axial direction of the buffer post.

[0011] Furthermore, a limiting boss is provided at one end of the buffer post inserted into the oil inlet pipe, and the outer diameter of the limiting boss is larger than the inner diameter of the buffer ring.

[0012] Furthermore, a sealing plug is provided at the bottom of the cylinder, and the buffer column is connected to the sealing plug.

[0013] Furthermore, the buffer post is connected to the sealing plug via a resilient cylindrical pin.

[0014] Furthermore, an O-ring is provided between the sealing plug and the cylinder.

[0015] Furthermore, the buffer ring has a buffer surface at its end facing the oil inlet pipe, and the buffer surface is a conical surface.

[0016] The beneficial effects of this utility model are that it eliminates the need for a separate one-way valve structure. Instead, it modifies the cylinder structure by incorporating a one-way valve flow channel on the piston rod assembly, within which ball bearings are installed to achieve the one-way valve function. Furthermore, the presence of multiple damping holes on the piston rod allows even compact cylinders to achieve rapid start-up via the one-way valve flow channel. This application features a simple structure with low machining precision and assembly requirements, providing a solution for compact cylinders requiring long buffer strokes. It is applicable to various industries, including multi-stage cylinders, engineering cylinders, and metallurgical cylinders.

[0017] Furthermore, the floating buffer ring in this application allows the buffer ring and piston rod to function as a one-way valve when oil enters the rodless chamber, enabling rapid oil entry and quick cylinder start-up. The annular cavity formed between the inner hole of the buffer ring and the outer circle of the buffer column provides damping, preventing severe impacts caused by inertial forces at the end of the piston's stroke, thus extending cylinder lifespan; improving system stability; reducing hydraulic system pressure fluctuations; preventing damage to pipelines or valves; reducing noise and vibration; and minimizing noise pollution. It also ensures stable equipment operation in complex working conditions, such as high-frequency reciprocating motion or heavy-load scenarios. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 This is a schematic diagram of the hydraulic cylinder with a buffer structure in this utility model.

[0020] Figure 2 It is used to embody Figure 1 Enlarged view of part A of the rod-cavity buffer structure and the rodless cavity buffer structure.

[0021] Figure 3 This is a schematic diagram of the structure of the second piston rod in this utility model.

[0022] In the diagram: 1. Outer cylinder; 2. First piston rod; 3. Second piston rod; 4. First piston; 5. Second piston; 6. Fixing nut; 7. Rodless chamber; 8. Rod chamber; 9. First guide sleeve; 10. Second guide sleeve; 11. Buffer ring; 12. Buffer column; 13. Sealing plug; 14. Elastic cylindrical pin; 15. O-ring; 16. Limiting boss; 17. Oil inlet pipe; 18. One-way valve flow channel; 19. Sealing oil chamber; 20. Ball bearing; 21. Receiving groove; 22. Annular channel; 23. Damping hole; 24. O-ring seal; 25. Retaining ring; 26. Rod chamber oil port; 27. Rodless chamber oil port. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0024] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] A hydraulic cylinder with a buffer structure includes a hydraulic cylinder body, a rodless chamber buffer structure, and a rod chamber buffer structure. The hydraulic cylinder body has a rod chamber 8 and a rodless chamber 7. The rodless chamber buffer structure buffers the oil inlet and outlet processes of the rodless chamber 7, and the rod chamber buffer structure buffers the oil inlet and outlet processes of the rod chamber 8. The hydraulic cylinder body can be configured as a single-stage or multi-stage cylinder, and the application of the rodless and rod chamber buffer structures is not limited.

[0027] In this embodiment, a multi-stage cylinder is used as an example. In this embodiment, the hydraulic cylinder body includes an outer cylinder 1, a first piston rod 2, and a second piston rod 3. The first piston rod 2 is inserted into the outer cylinder 1 and slides along the axial direction of the outer cylinder 1. A first piston 4 is provided on the outer side of one end of the first piston rod 2 inserted into the outer cylinder 1. The first piston 4 is sealed to the inner wall of the outer cylinder 1.

[0028] The first piston rod 2 is hollow, and the second piston rod 3 is inserted through the first piston rod 2 and slides along the axial direction of the first piston rod 2. The first piston rod 2 can be regarded as an inner cylinder. One end of the second piston rod 3 inserted into the first piston rod 2 is connected to the second piston 5 through a fixing nut 6. An O-ring 24 and a retaining ring 25 are provided between the fixing nut 6 and the second piston 5. The retaining ring 25 is provided on both sides of the O-ring 24. The second piston 5 is sealed with the inner wall of the first piston rod 2 and a hole sealing ring is provided. The second piston rod 3, the second piston 5, the fixing nut 6, the first piston rod 2, and the first piston 4 each constitute a piston rod assembly.

[0029] A first guide sleeve 9 is provided between the opening of the outer cylinder 1 and the first piston rod 2, and a second guide sleeve 10 is provided between the end of the first piston rod 2 away from the bottom of the outer cylinder 1 and the second piston rod 3. Further, a sliding bushing and a wire retaining ring 25 for the hole are provided between the second guide sleeve 10 and the second piston rod 3.

[0030] In this embodiment, a rodless cavity 7 is formed between the fixing nut 6, the first piston 4, the second piston 5 and the bottom of the outer cylinder 1, and a rod cavity 8 is formed between the second piston rod 3 and the first piston rod 2.

[0031] Furthermore, the second piston rod 3 is hollow, and an oil inlet pipe 17 is provided inside the second piston rod 3. A rodless chamber oil port 27 is provided on the rod head of the second piston rod 3. One end of the oil inlet pipe 17 is connected to the fixing nut 6, and the other end is connected to the rodless chamber oil port 27. A sealed oil chamber 19 is set inside the second piston rod 3 and outside the oil inlet pipe 17. The oil inlet pipe 17 is connected to the rodless chamber 7. A rod chamber oil port 26 is provided on the rod head of the second piston rod 3. The rod chamber oil port 26 is connected to the sealed oil chamber 19.

[0032] The rodless chamber buffer structure includes a buffer ring 11 and a buffer post 12. Specifically, the buffer post 12 is connected to the bottom of the outer cylinder 1 via a sealing plug 13. The buffer post 12 is connected to the sealing plug 13 via an elastic cylindrical pin 14. The sealing plug 13 is threaded to the bottom of the outer cylinder 1. The axial direction of the buffer post 12 coincides with the axial direction of the second piston rod 3. The buffer post 12 is inserted into the oil inlet pipe 17. An O-ring 15 is provided between the sealing plug 13 and the outer cylinder 1. The buffer ring 11 is located in the rodless chamber 7 and is coaxially sleeved on the buffer post 12. The buffer ring 11 can slide along the axial direction of the buffer post 12. It should be noted that the end of the buffer post 12 away from the bottom of the outer cylinder 1 abuts against the end of the oil inlet pipe 17. The end of the buffer ring 11 facing the oil inlet pipe 17 is provided with a buffer surface. The buffer surface can be a conical surface or a plane. In this embodiment, the buffer surface is a conical surface.

[0033] When oil enters the rodless chamber through port 27, the hydraulic oil pushes the buffer ring 11, causing it to move backward (in this embodiment, the bottom side of the outer cylinder 1 is defined as the rear end). The buffer ring 11 separates from the end of the inlet pipe 17. At this time, the rodless chamber buffer structure enters the one-way valve function, and the hydraulic oil can quickly enter the rodless chamber 7, thus enabling rapid start-up. When oil returns from the rodless chamber 7, the oil in the rodless chamber 7 pushes the buffer ring 11 toward the inlet pipe 17. The conical buffer surface is completely in contact with the end face of the inlet pipe 17, which plays a sealing role. The oil in the rodless chamber 7 can only pass through the annular gap between the buffer column 12 and the buffer ring 11, thereby reducing the return oil flow and playing a buffering role.

[0034] The buffer post 12 can be configured as a tapered post, so that when the buffer ring 11 moves along the axial direction of the buffer post 12, the flow area of ​​the annular gap between it and the buffer post 12 will change, and thus different strokes will create different buffering effects, i.e., variable buffering effect. A limiting boss 16 is provided at the end of the buffer post 12 away from the outer cylinder 1. The outer diameter of the limiting boss 16 is larger than the inner diameter of the buffer ring 11, which can limit the stroke of the buffer ring 11 and prevent the buffer ring 11 from falling out of the buffer post 12.

[0035] The rod-shaped chamber buffer structure includes a ball bearing 20, a one-way valve channel 18 disposed on a fixing nut 6, and multiple damping holes 23 disposed on the side wall of the second piston rod 3. An annular channel 22 is provided between the fixing nut 6 and the second piston rod 3, and the annular channel 22 communicates with the rod-shaped chamber 8. The one-way valve channel 18 communicates with the oil port 26 of the rod-shaped chamber. Multiple one-way valve channels 18 can be provided along the circumference of the second piston rod 3. In this embodiment, three one-way valve channels 18 are provided along the circumference of the second piston rod 3. One end of the one-way valve channel 18 communicates with the sealing oil chamber 19, and the other end is opposite to the annular channel 22. The end of the one-way valve channel 18 opposite to the annular channel 22 is provided as a receiving groove 21 for accommodating the ball bearing 20. The diameter of the receiving groove 21 is larger at the end near the annular channel 22, and the width of the annular channel 22 is smaller than the diameter of the ball bearing 20. Multiple damping holes 23 are arranged along the length of the second piston rod 3 and are located close to the side of the second piston 5. The damping holes 23 can be straight holes or stepped holes, and different damping effects can be formed by adjusting their size and position.

[0036] When oil enters the rod chamber through port 26, hydraulic oil enters the sealed oil chamber 19 and directly pushes open the ball 20 through the one-way valve passage 18. The hydraulic oil then enters the rod chamber 8 through the annular channel 22 and enters the rod chamber 8 through the damping hole 23, causing it to start rapidly. The second piston 5 moves toward the second guide sleeve 10. When returning oil, the ball 20 blocks the one-way valve passage 18, and the oil can only return through the damping hole 23. The positions of the damping hole 23 and the second guide sleeve 10 will gradually approach each other. When the first damping hole 23 is blocked by the second guide sleeve 10, the number of remaining damping holes 23 decreases, and the damping force generated is greater. That is, the closer to the second guide sleeve 10, the greater the damping force, forming variable damping. Thus, by changing the size and position of the damping hole 23, the damping force can be changed to achieve different buffering effects.

[0037] In this application, the buffer ring 11 is floating, so when oil enters the rodless chamber 7, the buffer ring 11 and the piston rod can also function as a one-way valve, allowing oil to quickly enter the rodless chamber 7 and start the cylinder quickly. The annular cavity formed between the inner hole of the buffer ring 11 and the outer circle of the buffer column 12 provides damping and buffering, thus preventing violent collisions caused by inertial forces when the piston reaches the end of its stroke at high speed, improving the service life of the cylinder; enhancing system stability, reducing hydraulic system pressure fluctuations, and preventing damage to pipelines or valves; reducing noise and vibration; lowering impact force, resulting in overall lower noise and vibration, reducing noise pollution; and ensuring stable operation of the equipment in complex working conditions, high-frequency reciprocating motion, or heavy-load scenarios.

[0038] Furthermore, this application eliminates the need for a separate one-way valve structure. Instead, it modifies the cylinder structure by incorporating a one-way valve flow channel 18 on the piston rod assembly. A ball bearing 20 is installed within this flow channel 18 to achieve the one-way valve function. Combined with multiple damping holes 23 on the piston rod, even compact cylinders can achieve rapid start-up via the one-way valve flow channel 18. As the piston rod moves, the multiple damping holes 23 engage with the guide sleeve, being blocked by the guide sleeve, thus providing variable damping buffering.

[0039] This application has a simple structure and low requirements for machining accuracy and assembly. It provides a solution for hydraulic cylinders with compact structures and long buffer strokes, applicable to various industries, including multi-stage cylinders, engineering cylinders, and metallurgical cylinders.

[0040] Furthermore, the buffer column 12 is fixed to the sealing plug 13 by the elastic cylindrical pin 14 or pin, and sealed by the O-ring 15, which can improve the stability of the installation of the buffer column 12 and the structural sealing effect. The sealing structure between the piston and the cylinder and between the guide sleeve and the piston rod can reduce the wear of the piston seal ring, guide sleeve and other components caused by impact.

[0041] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A hydraulic cylinder with a buffer structure, characterized in that, include, Cylinder, and A piston rod assembly is inserted into a cylinder and slides within the cylinder. The piston rod assembly is provided with a rod chamber oil port (26) and a sealing oil chamber (19) is provided inside the piston rod assembly. Guide sleeve, the guide sleeve is disposed between the outer cylinder (1) opening and the piston rod assembly; One-way valve flow channel (18), the one-way valve flow channel (18) is disposed on the piston rod assembly and communicates with the rod chamber oil port (26), and a ball (20) is disposed in the one-way valve flow channel (18); Multiple damping holes (23) are arranged on the piston rod assembly along the axial direction of the cylinder and communicate with the sealing oil chamber (19). As the piston rod assembly moves, the multiple damping holes (23) cooperate with the guide sleeve in sequence to change the damping at the damping hole (23).

2. The hydraulic cylinder with a buffer structure according to claim 1, characterized in that, The piston rod assembly includes a piston rod, a fixing nut (6), and a piston. The piston rod is inserted into the cylinder. The piston is connected to the end of the piston rod inserted into the cylinder by the fixing nut (6). The one-way valve passage (18) is provided on the fixing nut (6).

3. The hydraulic cylinder with a buffer structure according to claim 2, characterized in that, A rod chamber (8) is formed between the piston rod and the cylinder. An annular channel (22) is provided between the fixing nut (6) and the piston rod. The annular channel (22) is connected to the rod chamber (8). One end of the one-way valve flow channel (18) is connected to the sealing oil chamber (19), and the other end is connected to the annular channel (22). The end of the one-way valve flow channel (18) opposite to the annular channel (22) is set as a receiving groove (21) for accommodating the ball (20).

4. The hydraulic cylinder with a buffer structure according to claim 1, characterized in that, A rodless cavity (7) is formed between the bottom of the cylinder and the piston. A buffer column (12) is provided on the cylinder. An oil inlet pipe (17) is provided inside the piston rod. The oil inlet pipe (17) is connected to a fixing nut (6). The buffer column (12) is inserted into the oil inlet pipe (17).

5. The hydraulic cylinder with a buffer structure according to claim 4, characterized in that, A buffer ring (11) is fitted on the buffer column (12), and a gap is provided between the buffer ring (11) and the buffer column (12). The buffer ring (11) is located in the rodless cavity (7), and the buffer ring (11) slides relative to the buffer column (12) along the axial direction of the buffer column (12).

6. The hydraulic cylinder with a buffer structure according to claim 5, characterized in that, The buffer column (12) is inserted into the oil inlet pipe (17) at one end and is provided with a limiting boss (16). The outer diameter of the limiting boss (16) is larger than the inner diameter of the buffer ring (11).

7. The hydraulic cylinder with a buffer structure according to claim 1, characterized in that, A sealing plug (13) is provided at the bottom of the cylinder, and the buffer column (12) is connected to the sealing plug (13).

8. The hydraulic cylinder with a buffer structure according to claim 7, characterized in that, The buffer post (12) is connected to the sealing plug (13) via an elastic cylindrical pin (14).

9. The hydraulic cylinder with a buffer structure according to claim 7, characterized in that, An O-ring (15) is provided between the sealing plug (13) and the cylinder.

10. The hydraulic cylinder with a buffer structure according to claim 5, characterized in that, The buffer ring (11) has a buffer surface at the end facing the oil inlet pipe (17), and the buffer surface is a conical surface.

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