Hydraulic oil cylinder with multi-stage telescopic function

Abstract

The utility model relates to the technical field of hydraulic oil cylinders, and discloses a hydraulic oil cylinder with a multi-stage telescopic function, which comprises a cylinder barrel, a first-stage piston sleeve, a second-stage piston sleeve and a third-stage piston rod, the small third-stage piston rod is continuously sleeved with the two large first-stage piston sleeves and the two large second-stage piston sleeves to form a telescopic structure, and then the telescopic structure is connected with the cylinder barrel; when oil enters an oil port, the first-stage piston sleeve with a large effective action area is pushed to move and extend, then the second-stage piston sleeve with a small effective action area is pushed to move and extend, and finally the third-stage piston rod is pushed to move and extend, so that the stroke can be increased during working, the piston rod can be shortened during retracting, and the occupied space can be greatly reduced; the compact and flexible structure of the whole structure is improved, and the structure is suitable for occasions with limited installation space and long stroke requirements, such as telescopic arms of tipping cars and cranes.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic cylinder technology, specifically to a hydraulic cylinder with multi-stage telescopic function. Background Technology

[0002] A hydraulic cylinder is a hydraulic actuator that converts hydraulic energy into mechanical energy, performing 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, has no transmission backlash, and provides smooth movement. Therefore, it is widely used in the hydraulic systems of various machines. The output force of a hydraulic cylinder is directly proportional to the effective area of ​​the piston and the pressure difference between its two sides. A hydraulic cylinder basically consists of a cylinder barrel and cylinder head, a piston and piston rod, a sealing device, a cushioning device, and a venting device. The cushioning and venting devices are optional depending on the specific application, while the other devices are essential. Based on the common structural forms of hydraulic cylinders, they can be divided into four types: piston type, plunger type, telescopic type, and oscillating type.

[0003] Among them, the swing hydraulic cylinder has a wide range of applications, generally used in situations with high torque and small rotation angle, and applied in various mechanical equipment. Swing hydraulic cylinders can be divided into three types: gear and rack type, vane type, and spiral type. The principle of the gear and rack swing hydraulic cylinder is to convert the reciprocating motion of the hydraulic cylinder into the forward and reverse swing rotation of the gear shaft by driving the gear through the rack. At the same time, the thrust of the reciprocating cylinder is converted into the output torque of the gear shaft. Since the swing angle of the gear shaft is proportional to the length of the rack, the swing angle of the gear shaft can be arbitrarily selected and can be greater than 360°.

[0004] The existing hydraulic gate hoist cylinders mainly consist of a cylinder barrel, a piston, and a piston rod. The piston is housed inside the cylinder barrel, and the piston rod passes through it. The rear end of the cylinder barrel is connected to a rear cover, and a guide sleeve is installed between the front end of the cylinder barrel and the piston rod. When this type of cylinder is used in hydraulic gate hoists, because it only has one stage of extension, a longer stroke requires a longer installation space. To achieve a certain stroke, the length of the cylinder barrel and piston rod must be relatively long, resulting in a large installation distance and increased civil engineering investment. Utility Model Content

[0005] To overcome the technical problems existing in the prior art, this utility model provides a hydraulic cylinder with multi-stage telescopic function.

[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0007] A hydraulic cylinder with multi-stage telescopic function includes: a cylinder barrel, a primary piston sleeve, a secondary piston sleeve, and a tertiary piston rod; the primary piston sleeve is sleeved inside the cylinder barrel and can slide along the length of the cylinder barrel to form a primary rodless chamber and a primary rod chamber; the outer circumferential surface of the secondary piston sleeve is sleeved on the inner wall of the primary piston sleeve and can slide along the length of the primary piston sleeve to form a secondary rodless chamber and a secondary rod chamber; the outer circumferential surface of the tertiary piston rod is sleeved on the inner wall of the primary piston sleeve and can slide along the length of the secondary piston sleeve to form a tertiary rodless chamber and a tertiary rod chamber.

[0008] The three-stage piston rod is provided with an oil inlet and an oil return port at the same end; the oil inlet is connected to the first-stage rodless chamber, the second-stage rodless chamber and the third-stage rodless chamber respectively through an oil inlet channel; the oil return port is connected to the first-stage rod chamber, the second-stage rod chamber and the third-stage rod chamber respectively through an oil return channel.

[0009] Furthermore, the three-stage piston rod has a groove inside, the oil inlet channel is connected to a pipe and passes through the groove to form an oil inlet channel, and the oil return channel is the channel between the groove and the pipe.

[0010] Furthermore, the third-stage piston rod is provided with a third oil hole, and the oil return channel is connected to the third-stage rod chamber through the third oil hole.

[0011] Furthermore, the secondary piston sleeve is provided with a second oil hole, and the tertiary rod chamber is connected to the secondary rod chamber through the second oil hole.

[0012] Furthermore, the first-stage piston sleeve is provided with a first oil hole, and the second-stage rod chamber (202) is connected to the first-stage rod chamber through the first oil hole.

[0013] Furthermore, a first-stage piston head is connected to the end of the first-stage piston sleeve, the outer circumferential surface of the first-stage piston head slides on the inner wall of the cylinder, and the end of the first-stage piston sleeve away from the first-stage piston head extends out of the cylinder end.

[0014] Furthermore, a secondary piston head is connected to the end of the secondary piston sleeve, the outer circumferential surface of the secondary piston head slides on the inner wall of the primary piston sleeve, and the end of the secondary piston sleeve away from the secondary piston head extends out of the end of the primary piston sleeve.

[0015] Furthermore, a third-stage piston head is connected to the end of the third-stage piston rod, the outer circumferential surface of the third-stage piston head slides on the inner wall of the second-stage piston sleeve, and the end of the third-stage piston rod away from the third-stage piston head extends out of the end of the second-stage piston sleeve.

[0016] Furthermore, the cylinder and the end of the third-stage piston rod are provided with earrings that fit with other components, and the earrings are also provided with grease fitting holes for lubricating the earrings.

[0017] Preferably, the grease nipple hole at the end of the cylinder barrel and the grease nipple hole at the end of the third-stage piston rod are symmetrically arranged, so that the two ends of the hydraulic cylinder can be connected to other components through the grease nipple holes.

[0018] Furthermore, the ends of the first-stage piston sleeve, the second-stage piston sleeve, and the third-stage piston rod are each provided with a first-stage cylinder head, a second-stage cylinder head, and a third-stage cylinder head.

[0019] Preferably, the first-stage cylinder head is located at the tail of the first-stage piston sleeve, the second-stage cylinder head is located at the tail of the second-stage piston sleeve, and the third-stage cylinder head is located at the tail of the third-stage piston rod, to ensure the sealing of the rod chamber.

[0020] Compared with the prior art, the beneficial effects of this utility model's technical solution are:

[0021] ① By connecting the piston rod together with the plug sleeve into the cylinder, three-stage telescopic hydraulic pressure can be achieved;

[0022] The small piston rod is continuously sleeved inside two large piston sleeves. When oil enters through the oil port, it first pushes the first-stage piston sleeve with a larger effective working area to extend, then pushes the second-stage piston sleeve with a smaller effective working area to extend, and finally pushes the third-stage piston rod to extend. This allows the stroke to be increased during operation and shortened during retraction, which can greatly reduce the space occupied and improve the compactness and flexibility of the overall structure. It is suitable for occasions where installation space is limited but the stroke requirement is very long, such as the telescopic boom of dump trucks and cranes.

[0023] ② By inputting hydraulic oil with a constant flow rate into the oil port, the telescopic hydraulic cylinder extends step by step, and the effective working area decreases step by step, so the extension speed gradually increases. Therefore, the piston sleeve with a large effective working area has a low speed and a large thrust during the extension movement, realizing a high-thrust extension movement; when retracting, the movement thrust is small and the speed is high, realizing a rapid retraction.

[0024] ③ When the external load remains constant, the working pressure of the hydraulic cylinder gradually increases. The extension of the telescopic hydraulic cylinder relies on the oil pressure, and the retraction relies on its own weight or the load. Therefore, it is suitable for situations where the cylinder body is tilted or rotated vertically. In these cases, gravity can help the cylinder retract smoothly without the need for hydraulic power, thus improving the reliability and efficiency of the system.

[0025] ④ The hydraulic cylinder is equipped with lugs at both ends to connect with other components and maintain a stable connection posture;

[0026] The cylinder barrel and the end of the third-stage piston rod are provided with lugs that can be fitted with other components. The lugs can be fitted with other mechanical components (such as fixed brackets, connecting rods, etc.), which increases the stability and reliability of the connection. This ensures that the hydraulic cylinder maintains the accurate position and posture when subjected to tension, compression or lateral force during operation, and avoids loosening or falling off.

[0027] ⑤ Grease nipple holes are also provided at both ends of the hydraulic cylinder. The lugs and connected parts can be lubricated through the grease nipple holes. Since the lug connection part may be subjected to a large friction force during the operation of the hydraulic cylinder, regular lubrication can reduce wear and extend service life. The design of the grease nipple holes allows maintenance personnel to directly lubricate key moving parts at fixed points, improving maintenance efficiency and system durability.

[0028] ⑥ By placing the oil inlet and return ports at the same end of the three-stage piston rod, this design helps to reduce the overall size of the equipment in space-constrained applications. Especially in long-stroke or multi-stage hydraulic cylinders, it facilitates compact layout, installation, and maintenance. The centralized arrangement of oil ports also makes it easier to integrate more advanced control systems, such as proportional valves and servo valves. These control elements can achieve precise control of piston movement by accurately controlling the oil inlet and return flow. Attached Figure Description

[0029] To more clearly illustrate the technical solution of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 A schematic diagram of the extension and retraction of a hydraulic cylinder with multi-stage extension and retraction function;

[0031] Figure 2 This is a schematic diagram of the structure of a hydraulic cylinder with multi-stage telescopic function;

[0032] Figure 3 This is an enlarged schematic diagram of A.

[0033] in,

[0034] 1. Cylinder barrel; 101. First-stage rodless chamber; 102. First-stage rod chamber;

[0035] 2. First-stage piston sleeve; 201. Second-stage rodless chamber; 202. Second-stage rod chamber;

[0036] 3. Second-stage piston sleeve; 301. Third-stage rodless chamber; 302. Third-stage rod chamber;

[0037] 4. Three-stage piston rod;

[0038] 5. Oil inlet;

[0039] 6. Oil return port;

[0040] 7. Oil inlet channel;

[0041] 8. Oil return channel;

[0042] 9. Third oil hole;

[0043] 10. Second oil hole;

[0044] 11. First oil hole;

[0045] 12. First-stage piston head;

[0046] 13. Secondary piston head;

[0047] 14. Three-stage piston head;

[0048] 15. Earrings;

[0049] 16. Butter nozzle hole;

[0050] 17. Primary cylinder head;

[0051] 18. Secondary cylinder head;

[0052] 19. Three-stage cylinder head. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this application. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the described embodiments without creative effort are within the scope of protection of this application.

[0054] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0055] Example 1

[0056] like Figure 1-3As shown, this embodiment discloses a hydraulic cylinder with multi-stage telescopic function, including: a cylinder barrel 1, a primary piston sleeve 2, a secondary piston sleeve 3, and a tertiary piston rod 4; the primary piston sleeve 2 is sleeved inside the cylinder barrel 1 and can slide along the length of the cylinder barrel 1 to form a primary rodless chamber 101 and a primary rod chamber 102; the outer circumferential surface of the secondary piston sleeve 3 is sleeved on the inner wall of the primary piston sleeve 2 and can slide along the length of the primary piston sleeve 2 to form a secondary rodless chamber 201 and a secondary rod chamber 202; the outer circumferential surface of the tertiary piston rod 4 is sleeved on the inner wall of the primary piston sleeve 2 and can slide along the length of the secondary piston sleeve 3 to form a tertiary rodless chamber 301 and a tertiary rod chamber 302;

[0057] The three-stage piston rod 4 has an oil inlet 5 and an oil return port 6 at the same end; the oil inlet 5 is connected to the first-stage rodless chamber 101, the second-stage rodless chamber 201 and the third-stage rodless chamber 301 respectively through the oil inlet channel 7; the oil return port 6 is connected to the first-stage rod chamber 102, the second-stage rod chamber 202 and the third-stage rod chamber 302 respectively through the oil return channel 8.

[0058] When the hydraulic cylinder begins to extend, initially only the piston system consisting of the innermost piston sleeve 2 works, resulting in a large effective working area, which leads to a low piston speed and high thrust. As the outer pistons extend one by one, the working piston area gradually decreases (because with each extension, a portion of the sleeve is exposed, reducing the effective thrust area of ​​the piston). Since the external load remains constant while the effective working area decreases, according to the formula pressure = force / area, the hydraulic system must provide higher pressure to maintain a constant output force in order to overcome the constant external load. Therefore, as the extension and retraction process proceeds, the working pressure of the hydraulic cylinder gradually increases to meet the consistent output force requirements under different stages or working conditions, thereby broadening its application range in engineering, manufacturing, and other fields.

[0059] When the external load remains constant, the working pressure of the hydraulic cylinder gradually increases. The extension of the telescopic hydraulic cylinder relies on the oil pressure, and the retraction relies on its own weight or the load. Therefore, it is suitable for situations where the cylinder body is tilted or rotated vertically. In these cases, gravity can help the cylinder retract smoothly without the need for hydraulic power, thus improving the reliability and efficiency of the system.

[0060] Specifically, the oil inlet 5 and the oil return port 6 are located at the same end of the three-stage piston rod 4. In space-constrained applications, this design helps to reduce the overall size of the equipment, especially in long-stroke or multi-stage hydraulic cylinders. It facilitates compact layout, installation and maintenance. The centralized arrangement of oil ports also makes it easier to integrate more advanced control systems, such as proportional valves and servo valves. These control elements can achieve precise control of piston movement by accurately controlling the oil inlet and return flow.

[0061] In one specific implementation, the three-stage piston rod 4 has a groove inside, the oil inlet channel 7 is connected to a pipe and passes through the groove to form the oil inlet channel 7, and the oil return channel 8 is the channel between the groove and the pipe.

[0062] The third-stage piston rod 4 is provided with a third oil hole 9, and the oil return channel 8 is connected to the third-stage rod chamber 302 through the third oil hole 9.

[0063] The second oil hole 10 is provided inside the second-stage piston sleeve 3, and the third-stage rod chamber 302 is connected to the second-stage rod chamber 202 through the second oil hole 10.

[0064] The first-stage piston sleeve 2 is provided with a first oil hole 11, and the second-stage rod chamber 202 is connected to the first-stage rod chamber 102 through the first oil hole 11.

[0065] Specifically, when hydraulic oil with a constant flow rate enters from the inlet 5, the hydraulic oil first enters the first-stage rodless chamber 101 and drives the first-stage piston sleeve 2 with a larger effective working area to extend. The hydraulic oil in the first-stage rodless chamber 101 passes through the first oil hole 11, the second oil hole 10 and the third oil hole 9 into the return oil channel 8, and flows back to the hydraulic system from the return oil port 6 through the return oil channel 8.

[0066] When the first-stage piston sleeve 2 extends to the top, the hydraulic oil first enters the second-stage rodless chamber 201 and drives the second-stage piston sleeve 3 to move and extend. The first oil hole 11 begins to close, and the hydraulic oil in the second-stage rodless chamber 201 passes through the second oil hole 10 and the third oil hole 9 into the return oil channel 8 and flows back to the hydraulic system from the return oil port 6 through the return oil channel 8.

[0067] When the secondary piston sleeve 3 extends to the top, the hydraulic oil first enters the tertiary rodless chamber 301 and drives the tertiary piston rod 4 to extend. The second oil hole 10 begins to close, and the hydraulic oil in the tertiary rodless chamber 301 passes through the third oil hole 9 and enters the return oil channel 8. It then flows back to the hydraulic system from the return oil port 6 through the return oil channel 8.

[0068] By inputting hydraulic oil with a constant flow rate into the oil port, the telescopic hydraulic cylinder extends step by step, and the effective working area decreases step by step, causing the extension speed to gradually increase. Therefore, the piston sleeve with a large effective working area has a low speed and a large thrust during the extension movement, achieving a high-thrust extension movement; when retracting, the movement thrust is small and the speed is high, achieving rapid retraction.

[0069] In one specific implementation, a first-stage piston head 12 is connected to the end of the first-stage piston sleeve 2. The outer circumferential surface of the first-stage piston head 12 slides on the inner wall of the cylinder 1, and the end of the first-stage piston sleeve 2 away from the first-stage piston head 12 extends out of the end of the cylinder 1.

[0070] The end of the secondary piston sleeve 3 is connected to the secondary piston head 13. The outer circumferential surface of the secondary piston head 13 slides on the inner wall of the primary piston sleeve 2. The end of the secondary piston sleeve 3 away from the secondary piston head 13 extends out of the end of the primary piston sleeve 2.

[0071] The end of the third-stage piston rod 4 is connected to the third-stage piston head 14. The outer circumferential surface of the third-stage piston head 14 slides on the inner wall of the second-stage piston sleeve 3. The end of the third-stage piston rod 4 away from the third-stage piston head 14 extends out of the end of the second-stage piston sleeve 3.

[0072] Specifically, by connecting the three-stage piston rod 4 together with the sleeve into the cylinder 1, a three-stage telescopic structure is formed. Each stage of the telescopic sleeve is provided with a piston head (first-stage piston head 12 and second-stage piston head 13), so that each stage piston and sleeve form an independent pressure chamber (first-stage rodless chamber 101 and second-stage rodless chamber 201). Different pressures can be applied to different working stages or load requirements, thereby achieving more precise pressure control. Through the step-by-step transmission, the movement of each stage piston is superimposed on the next stage, which can achieve a longer stroke within the limited length of the cylinder 1.

[0073] When oil enters through the oil port, it first pushes the first-stage piston sleeve 2, which has a larger effective working area, to extend. Then, it pushes the second-stage piston sleeve 3, which has a smaller effective working area, to extend. Finally, it pushes the third-stage piston rod 4 to extend. This allows the stroke to be increased during operation and shortened during retraction, which can greatly reduce the space occupied and improve the compactness and flexibility of the overall structure. It is suitable for occasions where installation space is limited but the stroke requirement is very long, such as the telescopic boom of dump trucks and cranes.

[0074] Example 2

[0075] like Figure 1-3 As shown, this embodiment discloses a hydraulic cylinder with multi-stage telescopic function, including: a cylinder barrel 1, a primary piston sleeve 2, a secondary piston sleeve 3, and a tertiary piston rod 4; the primary piston sleeve 2 is sleeved inside the cylinder barrel 1 and can slide along the length of the cylinder barrel 1 to form a primary rodless chamber 101 and a primary rod chamber 102; the outer circumferential surface of the secondary piston sleeve 3 is sleeved on the inner wall of the primary piston sleeve 2 and can slide along the length of the primary piston sleeve 2 to form a secondary rodless chamber 201 and a secondary rod chamber 202; the outer circumferential surface of the tertiary piston rod 4 is sleeved on the inner wall of the primary piston sleeve 2 and can slide along the length of the secondary piston sleeve 3 to form a tertiary rodless chamber 301 and a tertiary rod chamber 302;

[0076] The three-stage piston rod 4 has an oil inlet 5 and an oil return port 6 at the same end; the oil inlet 5 is connected to the first-stage rodless chamber 101, the second-stage rodless chamber 201 and the third-stage rodless chamber 301 respectively through the oil inlet channel 7; the oil return port 6 is connected to the first-stage rod chamber 102, the second-stage rod chamber 202 and the third-stage rod chamber 302 respectively through the oil return channel 8.

[0077] In one specific implementation, the ends of the cylinder 1 and the third-stage piston rod 4 are provided with earrings 15 that are fitted with other components, and the earrings 15 are also provided with grease nipple holes 16 for lubricating the earrings 15.

[0078] Specifically, the cylinder barrel 1 and the end of the third-stage piston rod 4 at both ends of the hydraulic cylinder are provided with lugs 15 that can be sleeved with other components. The lugs 15 can be sleeved with other mechanical components (such as fixed brackets, connecting rods, etc.), which increases the stability and reliability of the connection. This ensures that the hydraulic cylinder maintains an accurate position and posture when subjected to tension, compression or lateral force during operation, and avoids loosening or falling off.

[0079] Specifically, grease nipple holes 16 are provided at both ends of the hydraulic cylinder, through which lubricant can be applied to the earring 15 and the connected parts. Since the connecting parts of the earring 15 may be subjected to large friction during the operation of the hydraulic cylinder, regular lubrication can reduce wear and extend service life. The design of the grease nipple holes 16 allows maintenance personnel to directly lubricate key moving parts at specific points, improving maintenance efficiency and system durability.

[0080] Example 3

[0081] like Figure 1-3 As shown, this embodiment discloses a hydraulic cylinder with multi-stage telescopic function, including: a cylinder barrel 1, a primary piston sleeve 2, a secondary piston sleeve 3, and a tertiary piston rod 4; the primary piston sleeve 2 is sleeved inside the cylinder barrel 1 and can slide along the length of the cylinder barrel 1 to form a primary rodless chamber 101 and a primary rod chamber 102; the outer circumferential surface of the secondary piston sleeve 3 is sleeved on the inner wall of the primary piston sleeve 2 and can slide along the length of the primary piston sleeve 2 to form a secondary rodless chamber 201 and a secondary rod chamber 202; the outer circumferential surface of the tertiary piston rod 4 is sleeved on the inner wall of the primary piston sleeve 2 and can slide along the length of the secondary piston sleeve 3 to form a tertiary rodless chamber 301 and a tertiary rod chamber 302;

[0082] The three-stage piston rod 4 has an oil inlet 5 and an oil return port 6 at the same end; the oil inlet 5 is connected to the first-stage rodless chamber 101, the second-stage rodless chamber 201 and the third-stage rodless chamber 301 respectively through the oil inlet channel 7; the oil return port 6 is connected to the first-stage rod chamber 102, the second-stage rod chamber 202 and the third-stage rod chamber 302 respectively through the oil return channel 8.

[0083] In one specific implementation, the ends of the first-stage piston sleeve 2, the second-stage piston sleeve 3, and the third-stage piston rod 4 are all provided with a first-stage cylinder head 17, a second-stage cylinder head 18, and a third-stage cylinder head 19.

[0084] Specifically, the first-stage cylinder head 17, the second-stage cylinder head 18, and the third-stage cylinder head 19 are not only physically connected, but also serve as sealing elements between the telescopic components, ensuring the sealing of the hydraulic system under high-pressure working conditions, preventing hydraulic oil leakage, and maintaining system pressure stability and efficiency.

[0085] Specifically, the first-stage cylinder head 17, the second-stage cylinder head 18, and the third-stage cylinder head 19 are provided with threads, which can be used to detachably connect the ends of the first-stage piston sleeve 2, the second-stage piston sleeve 3, and the third-stage piston rod 4, respectively, facilitating subsequent disassembly, assembly, and maintenance operations.

[0086] Working principle

[0087] When the hydraulic cylinder begins to extend, initially only the piston system consisting of the innermost piston sleeve 2 works, resulting in a large effective working area, which leads to a low piston speed and high thrust. As the outer pistons extend one by one, the working piston area gradually decreases (because with each extension, a portion of the sleeve is exposed, reducing the effective thrust area of ​​the piston). Since the external load remains constant while the effective working area decreases, according to the formula pressure = force / area, the hydraulic system must provide higher pressure to maintain a constant output force in order to overcome the constant external load. Therefore, as the extension and retraction process proceeds, the working pressure of the hydraulic cylinder gradually increases to meet the consistent output force requirements under different stages or working conditions, thereby broadening its application range in engineering, manufacturing, and other fields.

[0088] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A hydraulic cylinder with multi-stage telescopic function, characterized in that, include: The cylinder (1), the first-stage piston sleeve (2), the second-stage piston sleeve (3), and the third-stage piston rod (4) are arranged in the cylinder (1). The first-stage piston sleeve (2) is fitted inside the cylinder (1) and can slide along the length of the cylinder (1) to form a first-stage rodless chamber (101) and a first-stage rod chamber (102). The outer circumferential surface of the second-stage piston sleeve (3) is fitted onto the inner wall of the first-stage piston sleeve (2) and can slide along the length of the first-stage piston sleeve (2) to form a second-stage rodless chamber (201) and a second-stage rod chamber (202). The outer circumferential surface of the third-stage piston rod (4) is fitted onto the inner wall of the first-stage piston sleeve (2) and can slide along the length of the second-stage piston sleeve (3) to form a third-stage rodless chamber (301) and a third-stage rod chamber (302). The three-stage piston rod (4) has an oil inlet (5) and an oil return port (6) at the same end; the oil inlet (5) is connected to the first-stage rodless chamber (101), the second-stage rodless chamber (201) and the third-stage rodless chamber (301) through the oil inlet channel (7); the oil return port (6) is connected to the first-stage rod chamber (102), the second-stage rod chamber (202) and the third-stage rod chamber (302) through the oil return channel (8).

2. The hydraulic cylinder with multi-stage telescopic function according to claim 1, characterized in that, The three-stage piston rod (4) has a groove inside. The oil inlet channel (7) is connected to a pipe and passes through the groove to form the oil inlet channel (7). The oil return channel (8) is the channel between the groove and the pipe.

3. The hydraulic cylinder with multi-stage telescopic function according to claim 1, characterized in that, The third-stage piston rod (4) is provided with a third oil hole (9), and the oil return channel (8) is connected to the third-stage rod chamber (302) through the third oil hole (9).

4. The hydraulic cylinder with multi-stage telescopic function according to claim 1, characterized in that, The secondary piston sleeve (3) is provided with a second oil hole (10), and the tertiary rod chamber (302) is connected to the secondary rod chamber (202) through the second oil hole (10).

5. The hydraulic cylinder with multi-stage telescopic function according to claim 1, characterized in that, The first-stage piston sleeve (2) is provided with a first oil hole (11), and the second-stage rod chamber (202) is connected to the first-stage rod chamber (102) through the first oil hole (11).

6. The hydraulic cylinder with multi-stage telescopic function according to claim 1, characterized in that, The first-stage piston sleeve (2) is connected to a first-stage piston head (12) at its end. The outer circumferential surface of the first-stage piston head (12) slides on the inner wall of the cylinder (1). The end of the first-stage piston sleeve (2) away from the first-stage piston head (12) extends out of the end of the cylinder (1).

7. The hydraulic cylinder with multi-stage telescopic function according to claim 1, characterized in that, The end of the secondary piston sleeve (3) is connected to the secondary piston head (13). The outer circumferential surface of the secondary piston head (13) slides on the inner wall of the primary piston sleeve (2). The end of the secondary piston sleeve (3) away from the secondary piston head (13) extends out of the end of the primary piston sleeve (2).

8. The hydraulic cylinder with multi-stage telescopic function according to claim 1, characterized in that, The end of the third-stage piston rod (4) is connected to the third-stage piston head (14). The outer circumferential surface of the third-stage piston head (14) slides on the inner wall of the second-stage piston sleeve (3). The end of the third-stage piston rod (4) away from the third-stage piston head (14) extends out of the end of the second-stage piston sleeve (3).

9. The hydraulic cylinder with multi-stage telescopic function according to claim 1, characterized in that, The cylinder (1) and the end of the third-stage piston rod (4) are provided with earrings (15) that are fitted with other components. The earrings (15) are also provided with grease nipple holes (16) for lubricating the earrings (15).

10. The hydraulic cylinder with multi-stage telescopic function according to claim 1, characterized in that, The ends of the first-stage piston sleeve (2), the second-stage piston sleeve (3), and the third-stage piston rod (4) are all provided with a first-stage cylinder head (17), a second-stage cylinder head (18), and a third-stage cylinder head (19).

Images