Hydraulic cylinder with anti-eccentric wear

Abstract

The application provides a hydraulic cylinder with anti-eccentric wear, and relates to the technical field of hydraulic cylinders. The hydraulic cylinder comprises a cylinder body, a piston and a piston rod. A sealing ring is fixed on the outer side wall of the piston. The piston and the piston rod are rotationally connected through a thrust bearing. A screw rod is rotationally connected to the inner end face of the cylinder body through a one-way bearing. A screw groove is arranged at the center of the end face of the piston for the screw rod to be inserted and matched. A ball bearing is further arranged between the piston and the piston rod. The inner ring surface of the ball bearing is in interference fit with the piston rod, and the outer ring surface of the ball bearing is in interference fit with the piston. When the hydraulic cylinder is shortened to the shortest, the piston and the sealing ring can be automatically rotated, the eccentric wear position of the bottom of the sealing ring when the cylinder body is inclined is changed, the same position of the sealing ring is prevented from being eccentrically worn all the time, and the service life of the sealing ring is prolonged. The structure for realizing the rotation of the piston is completely built-in the cylinder body, and the sealing performance of the hydraulic cavity is not affected.

Description

Technical Field

[0001] This application relates to the field of hydraulic cylinder technology, and in particular to a hydraulic cylinder with anti-wear properties. Background Technology

[0002] Hydraulic cylinders extend and retract by the inflow and outflow of hydraulic oil, which is delivered by a hydraulic pump. Hydraulic cylinders have the advantage of high thrust and are widely used in various engineering machinery and manufacturing.

[0003] The utility model patent with announcement number CN209872193U discloses a double hydraulic cylinder boom extension mechanism for a truck-mounted crane. It includes a truck-mounted crane body, a swivel seat mounted on the truck-mounted crane body, a boom support seat mounted on the swivel seat, a boom extension arm mounted on top of the boom support seat, and a cylinder connected between the boom support seat and the boom extension arm. The bottom of the boom extension arm is connected to a connecting groove, and the bottom of the connecting groove is connected to a cylinder connection part and a support connection part. A support device is connected between the cylinder connection part and the support connection part, and the cylinder and the cylinder connection part are hinged together.

[0004] For the hydraulic cylinders mentioned above, the weight of the piston cannot be ignored for cylinders with larger diameters. Since the cylinder body is in a significantly tilted state during use, the piston inside the cylinder experiences greater wear on the side that contacts the bottom of the cylinder wall than on the side that contacts the top of the cylinder wall. This can easily lead to uneven wear at the bottom of the piston, and uneven wear on the seals can cause leakage problems. Summary of the Invention

[0005] This application provides a hydraulic cylinder that prevents uneven wear. When the cylinder is shortened to its limit position, it can automatically rotate the piston angle to avoid leakage caused by uneven wear of the piston seal and extend its service life.

[0006] This application provides a hydraulic cylinder for preventing uneven wear, which adopts the following technical solution: A hydraulic cylinder for preventing uneven wear includes a cylinder body, a piston, and a piston rod. A sealing ring is fixedly fitted on the outer side wall of the piston. The piston and piston rod are rotatably connected through a thrust bearing. A helical rod is rotatably connected to the inner end face of the cylinder body through a one-way bearing. A helical groove is provided at the center of the end face of the piston for the helical rod to be inserted and fitted.

[0007] By adopting the above technical solution, the screw rod only inserts into the helical groove when the piston moves to its lowest position within the cylinder. The rotation direction of the one-way bearing is set such that the screw rod cannot rotate during insertion into the helical groove, thus driving the piston to rotate through the helical contact surface. During the piston's ascent, the one-way bearing allows the screw rod to rotate; during the screw rod's withdrawal from the helical groove, the screw rod rotates adaptively, while the piston does not rotate. This ensures that each time the piston moves to its lowest point, the piston and sealing ring rotate at an angle, preventing the sealing ring from continuously wearing unevenly at the same position when the cylinder is tilted, thus improving the problem of uneven wear.

[0008] Optionally, the sealing ring is made of PTFE bronze composite material.

[0009] By adopting the above technical solution, it has the advantages of good wear resistance and low frictional resistance.

[0010] Optionally, the cross-sections of the spiral rod and the spiral groove are both cross-shaped, the end of the spiral rod is a pointed tip, and the opening of the spiral groove is chamfered.

[0011] By adopting the above technical solution, it is convenient to insert the screw rod and the screw groove, and it can transmit torque.

[0012] Optionally, the rotation angle of the screw rod and the screw groove is less than 30 degrees.

[0013] By adopting the above technical solution, the piston only rotates a small angle each time it moves to the lowest position, resulting in little resistance and making it easy to achieve piston rotation.

[0014] Optionally, the piston includes a seat, a first pressure cap, and a second pressure cap stacked together. The sealing ring is provided in two layers. A groove first is formed between the seat and the pressure cap, and a groove second is formed between the first pressure cap and the second pressure cap. The two sealing rings are respectively located in the first groove and the second groove.

[0015] By adopting the above technical solution, the sealing performance is improved by setting two sealing rings; the sealing rings are accommodated by groove one and groove two, preventing axial movement between them and the piston. The stacked seat, gland one, and gland two facilitate the installation and removal of the sealing rings, allowing the use of complete annular sealing rings for better sealing performance.

[0016] Optionally, the base and the pressure cover are fixed together by a plurality of bolts, and the pressure cover one and the pressure cover two are fixed together by a plurality of bolts, and the pressure cover two is provided with a clearance hole for the bolts to pass through.

[0017] By adopting the above technical solution, bolt one can be removed independently without removing bolt two through the clearance hole, thus facilitating the disassembly and assembly of the sealing ring in groove one. Any sealing ring that malfunctions can be replaced individually, making the process more convenient.

[0018] Optionally, the inner wall of the sealing ring is integrally formed with a ring portion, which is clamped by the piston's stacked assembly.

[0019] By adopting the above technical solution, the sealing ring is prevented from rotating relative to the piston through the compression structure of the ring, while ensuring sealing performance.

[0020] Optionally, a ball bearing is also provided between the piston and the piston rod, wherein the inner ring surface of the ball bearing is interference-fitted with the piston rod, and the outer ring surface of the ball bearing is interference-fitted with the piston.

[0021] By adopting the above technical solution and using the interference fit of ball bearings, axial movement between the piston and piston rod is avoided, and an additional rotating connection position is added, making it more stable.

[0022] Optionally, hinge seats are fixed to the ends of the cylinder and piston rod that are far apart from each other.

[0023] By adopting the above technical solution, the installation of this hydraulic cylinder with external structures is convenient, and it is mostly used in cranes.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. When the hydraulic cylinder is retracted to its shortest length, it can automatically rotate the piston and the sealing ring, which changes the position of the bottom of the sealing ring when the cylinder body is tilted, avoids the sealing ring from wearing off at the same position, and extends the service life of the sealing ring. 2. The structure that enables piston rotation is completely built into the cylinder body, without affecting the sealing of the hydraulic chamber; 3. It can use a complete annular sealing ring, which improves the sealing performance and is easy to disassemble and assemble. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of a hydraulic cylinder designed to prevent uneven wear, according to one embodiment. Figure 2 yes Figure 1 A magnified view of a portion of the image; Figure 3 This is a perspective view of the screw rod and screw groove in an embodiment.

[0026] Explanation of reference numerals in the attached drawings: 1. Cylinder body; 2. Piston; 3. Piston rod; 11. Hinge seat; 4. Sealing ring; 31. Thrust bearing; 32. Ball bearing; 21. Seat body; 22. Pressure cap one; 23. Pressure cap two; 24. Groove one; 25. Groove two; 41. Ring; 26. Bolt one; 27. Bolt two; 28. Clearance hole; 51. One-way bearing; 5. Helical rod; 20. Helical groove. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the accompanying drawings.

[0028] Reference Figure 1 This embodiment discloses a hydraulic cylinder for preventing uneven wear, including a cylinder body 1, a piston 2 and a piston rod 3. The ends of the cylinder body 1 and the piston rod 3 that are far apart from each other are respectively fixed with hinge seats 11, which facilitates the installation of this hydraulic cylinder with external structures. This hydraulic cylinder is in an inclined state when in use and is mostly used in cranes.

[0029] Reference Figure 1 and Figure 2 A sealing ring 4 is fixedly fitted onto the outer wall of piston 2. Piston 2 and piston rod 3 are rotatably connected via a thrust bearing 31. A ball bearing 32 is also provided between piston 2 and piston rod 3. The inner ring surface of the ball bearing 32 is interference-fitted with piston rod 3, and the outer ring surface of the ball bearing 32 is interference-fitted with piston 2. The interference fit of the ball bearing 32 prevents axial movement between piston 2 and piston rod 3 and adds a rotatable connection point, making it more stable. When piston rod 3 extends outward, it is the power stroke, with a large thrust, which is mainly transmitted by the thrust bearing 31. The thrust bearing 31 is constructed to withstand this force and prevent damage. When piston rod 3 retracts, it is the reset stroke, with a smaller force, and the thrust bearing 31 still bears the pressure from above.

[0030] The sealing ring 4 is made of PTFE bronze composite material, which has the advantages of good wear resistance and low frictional resistance. The piston 2 includes a stacked seat 21, a first gland 22, and a second gland 23, which together form a stacked assembly. Two sealing rings 4 are provided to enhance the sealing effect. A groove 24 is formed between the seat 21 and the first gland 22, and a groove 25 is formed between the first gland 22 and the second gland 23. The two sealing rings 4 are located in the first groove 24 and the second groove 25, respectively. The inner wall of the sealing ring 4 has an integrally formed ring portion 41, which is clamped by the stacked assembly of the piston 2. The clamping structure of the ring portion 41 prevents the sealing ring 4 from rotating relative to the piston 2, while ensuring a tight seal.

[0031] The base 21 and the first pressure cap 22 are fixed together by multiple bolts 26, and the first pressure cap 22 and the second pressure cap 23 are fixed together by multiple bolts 27. The second pressure cap 23 has a clearance hole 28 for the first bolt 26 to pass through. After removing the second bolt 27, the first pressure cap 22 and the second pressure cap 23 can be separated, thus facilitating the disassembly and assembly of the sealing ring 4 in the second groove 25. Through the clearance hole 28, the first bolt 26 can be removed separately without removing the second bolt 27, thus facilitating the disassembly and assembly of the sealing ring 4 in the first groove 24. In summary, any sealing ring 4 can be replaced individually if it malfunctions, which is more convenient. The sealing ring 4 is a complete ring, which also facilitates disassembly and assembly, and provides good sealing performance.

[0032] Reference Figure 2 and Figure 3The inner end face of the cylinder 1 is rotatably connected to a helical rod 5 via a one-way bearing 51. The center of the end face of the piston 2 is provided with a helical groove 20 for the helical rod 5 to be inserted and fitted. To facilitate the insertion of the helical rod 5 and the helical groove 20, the cross-sections of the helical rod 5 and the helical groove 20 are both cross-shaped, the end of the helical rod 5 is a pointed tip, and the groove opening of the helical groove 20 is chamfered.

[0033] The rotation angle of the screw rod 5 and the screw groove 20 is less than 30 degrees. This design ensures that the piston 2 rotates only a small angle each time it reaches its lowest point, resulting in minimal resistance and facilitating piston 2 rotation. The piston 2 rotates together with the sealing ring 4, thus changing the position of the bottom of the sealing ring 4 when the cylinder body 1 is tilted, preventing continuous uneven wear at the same location. Preferably, the rotation angle of the screw rod 5 and the screw groove 20 is not divisible by 360 degrees. This ensures that after one revolution of the piston 2, the position of the sealing ring 4 is offset from its initial position, further mitigating uneven wear and ensuring uniform wear on the outer wall of the sealing ring 4.

[0034] The implementation principle of an anti-wear hydraulic cylinder according to an embodiment of this application is as follows: when the piston 2 moves to its lowest position within the cylinder body 1, the helical rod 5 is inserted into the helical groove 20. The rotation direction of the one-way bearing 51 is set such that during the insertion of the helical rod 5 into the helical groove 20, the helical rod 5 cannot rotate, thereby driving the piston 2 to rotate through the helical contact surface. During the lifting process of the piston 2, the one-way bearing 51 allows the helical rod 5 to rotate. During the process of the helical rod 5 being pulled out of the helical groove 20, the helical rod 5 rotates adaptively, and during this process, the piston 2 does not rotate due to the greater rotational resistance.

[0035] This ensures that each time the piston 2 moves to the lowest point, the piston 2 and the sealing ring 4 rotate at a small angle. When the cylinder body 1 is tilted, it prevents the sealing ring 4 from constantly wearing unevenly at the same position, thus improving the uneven wear problem and extending the service life of the sealing ring 4.

[0036] As a crane device, the hydraulic cylinder is generally retracted to its shortest length before shutdown, ensuring that it always rotates the piston 2 and sealing ring 4 during use. During operation, the hydraulic cylinder is rarely retracted to its shortest length, thus preventing the auger 5 from frequently inserting into the auger groove 20 and avoiding significant impact on the normal operation of the hydraulic cylinder.

[0037] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A hydraulic cylinder for preventing uneven wear, comprising a cylinder body (1), a piston (2) and a piston rod (3), wherein a sealing ring (4) is fixedly fitted onto the outer side wall of the piston (2), characterized in that: The piston (2) and piston rod (3) are connected by a thrust bearing (31). The inner end face of the cylinder (1) is rotatably connected to a helical rod (5) by a one-way bearing (51). The center of the end face of the piston (2) is provided with a helical groove (20) for the helical rod (5) to be inserted and fitted.

2. The anti-wear hydraulic cylinder according to claim 1, characterized in that: The sealing ring (4) is made of PTFE bronze composite material.

3. The anti-wear hydraulic cylinder according to claim 1, characterized in that: The cross-sections of the spiral rod (5) and the spiral groove (20) are both cross-shaped. The end of the spiral rod (5) is a pointed tip, and the groove opening of the spiral groove (20) is chamfered.

4. The anti-wear hydraulic cylinder according to claim 1, characterized in that: The rotation angle of the screw rod (5) and the screw groove (20) is less than 30 degrees.

5. A hydraulic cylinder for preventing uneven wear according to claim 1, characterized in that: The piston (2) includes a seat (21), a first pressure cap (22), and a second pressure cap (23) stacked together. The sealing ring (4) is provided in two places. A first groove (24) is formed between the seat (21) and the first pressure cap (22), and a second groove (25) is formed between the first pressure cap (22) and the second pressure cap (23). The two sealing rings (4) are located in the first groove (24) and the second groove (25) respectively.

6. A hydraulic cylinder for preventing uneven wear according to claim 5, characterized in that: The base (21) and the first cover (22) are fixed together by multiple bolts (26), and the first cover (22) and the second cover (23) are fixed together by multiple bolts (27). The second cover (23) is provided with a clearance hole (28) for the bolts (26) to pass through.

7. A hydraulic cylinder for preventing uneven wear according to claim 5, characterized in that: The inner wall of the sealing ring (4) is integrally formed with a ring portion (41), which is clamped by the stacked assembly of the piston (2).

8. A hydraulic cylinder for preventing uneven wear according to claim 1, characterized in that: A ball bearing (32) is also provided between the piston (2) and the piston rod (3). The inner ring surface of the ball bearing (32) is interference-fitted with the piston rod (3), and the outer ring surface of the ball bearing (32) is interference-fitted with the piston (2).

9. A hydraulic cylinder for preventing uneven wear according to claim 1, characterized in that: The cylinder (1) and piston rod (3) are respectively fixed with hinge seats (11) at their far ends.

Images