Oil cylinder convenient to center

Abstract

The utility model relates to the technical field of hydraulic oil cylinders, and provides an oil cylinder convenient to center, which comprises a cylinder body and a piston rod, the cylinder body is sequentially provided with an end cover, a positioning ring and a bottom plate, a first piston connected in the cylinder body in a sliding mode is fixed in the middle of the piston rod, and the first piston is limited between the end cover and the positioning ring. A first piston is arranged in the cylinder body, a second piston is arranged between the positioning ring and the bottom plate in a limited sliding mode, a first oil cavity is formed between the first piston and the end cover, a second oil cavity is formed between the first piston and the second piston, and a third oil cavity is formed between the second piston and the bottom plate. Accurate centering is achieved, a displacement sensor or complex electric control logic is not needed, the system complexity is reduced, and the operation reliability is improved.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic cylinder technology, and more specifically, to a cylinder that is easy to center. Background Technology

[0002] Hydraulic cylinders, as core actuators in construction machinery, directly affect the working efficiency and reliability of the equipment due to their positioning accuracy and stability. In practical applications of construction machinery, the piston rod of a hydraulic cylinder often needs to accurately return to a fixed position in the middle after multiple displacements, such as the frequent centering and resetting requirements of equipment like material handling machines and excavators.

[0003] However, traditional hydraulic cylinders typically rely on complex control methods and logic, such as displacement sensors, controller logic, and various solenoid valve assemblies, to achieve these functions. This not only increases the technical difficulty of implementation but also introduces significant performance and cost bottlenecks. This technical solution has significant drawbacks: poor control accuracy, making it difficult to meet the demands of high-precision operations; complex system structure, increasing the difficulty of installation, debugging, and maintenance; poor stability, making it prone to failure during long-term use; and high overall system cost, resulting in poor economic efficiency. Utility Model Content

[0004] The purpose of this invention is to provide a hydraulic cylinder that is easy to center, which solves the problems of complex centering operation, poor accuracy and stability of existing hydraulic cylinders.

[0005] This utility model is achieved through the following technical solution: a hydraulic cylinder that facilitates centering, comprising a cylinder body and a piston rod. The cylinder body is sequentially provided with an end cap, a positioning ring, and a base plate. A first piston is fixedly and slidably connected to the cylinder body in the middle of the piston rod. The first piston is limited between the end cap and the positioning ring. A second piston is limited and slidably positioned between the positioning ring and the base plate in the cylinder body. The space between the first piston and the end cap is a first oil chamber. The space between the first piston and the second piston is a second oil chamber. The space between the second piston and the base plate is a third oil chamber. When oil is injected into the first oil chamber and the third oil chamber at the same time, the second piston simultaneously abuts against the end of the piston rod and the positioning ring to achieve the centering and reset of the piston rod.

[0006] Furthermore, the end cap has a first oil injection hole communicating with the first oil chamber, the positioning ring has a second oil injection hole communicating with the second oil chamber, and the bottom plate has a third oil injection hole communicating with the third oil chamber.

[0007] Furthermore, the contact area between the second piston and the hydraulic oil is larger than that between the first piston and the hydraulic oil.

[0008] Furthermore, the distance between the end cap and the positioning ring is L1, the thickness of the first piston is D1, the length of the piston rod extending beyond the first piston is L2, the thickness of the positioning ring is D2, and L1-D1>L2-D2.

[0009] Furthermore, the second oil chamber is divided into two interconnected chambers by a positioning ring.

[0010] Furthermore, the piston rod is coaxially and sealingly slidably fitted inside the end cap and the positioning ring.

[0011] Furthermore, a hinged support is provided on the base plate.

[0012] This invention has at least the following advantages and beneficial effects: By simultaneously injecting oil into the first and third oil chambers, the second piston, near the bottom plate, is pushed by oil pressure to move towards the positioning ring. The first piston, near the end cap, is pushed by oil pressure to move towards the bottom plate. The contact surface between the second piston and the hydraulic oil is larger than that between the first piston and the hydraulic oil. According to Pascal's principle, under the same oil pressure, the thrust on the second piston is greater than the thrust on the first piston, forming a thrust difference. This thrust difference pushes the piston rod towards the end cap until the second piston abuts against the inner side of the positioning ring, achieving precise alignment. This eliminates the need for displacement sensors or complex electronic control logic, reducing system complexity and improving operational reliability. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the centering and reset state of a hydraulic cylinder that is easy to center, as provided by this utility model.

[0014] Figure 2 This utility model provides a schematic diagram of the extreme retraction state of a hydraulic cylinder that facilitates centering.

[0015] Figure 3 This is a schematic diagram of the extreme extension state of a hydraulic cylinder that facilitates centering, provided by this utility model.

[0016] Reference numerals: 1-Cylinder body, 11-First oil chamber, 12-Second oil chamber, 13-Third oil chamber, 2-Piston rod, 3-End cap, 30-First oil injection hole, 4-Positioning ring, 40-Second oil injection hole, 5-Base plate, 50-Third oil injection hole, 6-First piston, 7-Second piston, 8-Hinged support. Detailed Implementation

[0017] The specific implementation method is described below with reference to the accompanying drawings.

[0018] Example

[0019] like Figures 1 to 3As shown, this embodiment mainly discloses a hydraulic cylinder that facilitates centering, including a cylinder body 1 and a piston rod 2. The cylinder body 1 is sequentially provided with an end cap 3, a positioning ring 4, and a base plate 5. A first piston 6 is fixedly and slidably connected to the middle of the piston rod 2 within the cylinder body 1. The first piston 6 is limited between the end cap 3 and the positioning ring 4. A second piston 7 is limited and slidably positioned within the cylinder body 1 between the positioning ring 4 and the base plate 5. The first piston 6 and the end cap 3 form a first oil chamber 11, the first piston 6 and the second piston 7 form a second oil chamber 12, and the second piston 7 and the base plate 5 form a third oil chamber 13. When the first oil chamber 11 and the third oil chamber 13 are filled with oil simultaneously, the second piston 7 simultaneously abuts against the end of the piston rod 2 and the positioning ring 4 to achieve the centering and resetting of the piston rod 2. Specifically, the first piston 6 is integrally formed with the piston rod 2, and the second piston 7 is a separate block limited within the cylinder body 1. When only the first oil chamber 11 is filled with oil (e.g. Figure 2 As shown), the first piston 6 is pushed by oil pressure towards the base plate 5, and the piston rod 2 retracts to its limit position. When only the second oil chamber 12 is filled with oil (as shown), Figure 3 As shown), the first piston 6 is pushed by oil pressure towards the end cap 3, and the piston rod 2 extends to its limit position. When the first oil chamber 11 and the third oil chamber 13 are filled with oil simultaneously (as shown), the piston rod 2 extends to its limit position. Figure 1 As shown, the second piston 7, near the base plate 5, is pushed by oil pressure to move towards the positioning ring 4. The first piston 6, near the end cap 3, is also pushed by oil pressure to move towards the base plate 5. The contact area between the second piston 7 and the hydraulic oil is larger than that between the first piston 6 and the hydraulic oil. According to Pascal's principle, under the same oil pressure, the thrust on the second piston 7 is greater than the thrust on the first piston 6, forming a thrust difference. This thrust difference pushes the piston rod 2 towards the end cap 3 until the second piston 7 abuts against the inner side of the positioning ring 4, achieving precise alignment. This eliminates the need for displacement sensors or complex electronic control logic, reducing system complexity and improving operational reliability.

[0020] Furthermore, in specific implementations, the end cap 3 provided in this embodiment of the present invention has a first oil injection hole 30 communicating with the first oil chamber 11, the positioning ring 4 has a second oil injection hole 40 communicating with the second oil chamber 12, and the base plate 5 has a third oil injection hole 50 communicating with the third oil chamber 13. The end cap 3, positioning ring 4, and base plate 5 are each provided with independent oil injection holes, allowing three working conditions (oil injection into the first oil chamber 11 alone, oil injection into the second oil chamber 12 alone, and oil injection into the first oil chamber 11 and the third oil chamber 13 simultaneously) to be independently controlled by an oil circuit switch, ensuring the feasibility of different oil chamber filling logics. For example, during alignment, only the first oil injection hole 30 and the third oil injection hole 50 need to be opened simultaneously, while the second oil injection hole 40 is closed, to achieve oil filling into the first oil chamber 11 and the third oil chamber 13. This simplifies operation and avoids oil circuit confusion. Independent oil injection holes facilitate oil circuit inspection and replacement without requiring complete disassembly of the cylinder, reducing maintenance costs. It is adaptable to different types of hydraulic pumps and oil sources, offering strong versatility.

[0021] Furthermore, in a specific implementation, the distance between the end cap 3 and the positioning ring 4 provided in this embodiment of the present invention is L1, the thickness of the first piston 6 is D1, the length by which the piston rod 2 extends inward beyond the first piston 6 is L2, and the thickness of the positioning ring 4 is D2, and L1-D1>L2-D2. During the alignment process, it is ensured that the first piston 6 does not come into contact with the end cap 3 before the second piston 7 abuts against the positioning ring 4. For example, if L1-D1≤L2-D2, during the alignment process, the first piston 6 may prematurely contact the end cap 3 when it moves outward, while the second piston 7 has not yet abutted against the positioning ring 4, resulting in alignment failure. This parameter relationship ensures the reliability of the mechanical limit through geometric constraints.

[0022] Furthermore, in a specific implementation, the second oil chamber 12 provided in this embodiment of the present invention is divided into two interconnected chambers by a positioning ring 4. Specifically, the positioning ring 4 is welded and fixed inside the cylinder body 1. When oil is injected into the second oil chamber 12 through the second oil injection hole 40, the hydraulic oil simultaneously acts on the first piston 6 and the second piston 7.

[0023] Furthermore, in a specific implementation, the piston rod 2 described above in this embodiment of the invention is coaxially and slidably sleeved within the end cover 3 and the positioning ring 4. Specifically, the piston rod 2 and the cylinder 1 are also coaxially arranged to ensure linear movement of the piston rod 2, reduce uneven wear caused by lateral forces, and extend the life of the seal.

[0024] Furthermore, in a specific implementation, a hinged support 8 is provided on the base plate 5 provided in this embodiment of the invention. This allows for direct connection to the engineering robotic arm, reducing intermediate connecting parts and improving structural rigidity.

Claims

1. A centering cylinder for facilitating centering, comprising a cylinder body (1) and a piston rod (2), characterized in that, The cylinder body (1) is provided with an end cap (3), a positioning ring (4) and a base plate (5) in sequence. The piston rod (2) is fixed in the middle and slidably connected to the first piston (6) in the cylinder body (1). The first piston (6) is limited between the end cap (3) and the positioning ring (4). The second piston (7) is limited and slidably connected between the positioning ring (4) and the base plate (5) in the cylinder body (1). The first piston (6) and the end cap (3) form a first oil chamber (11). The first piston (6) and the second piston (7) form a second oil chamber (12). The second piston (7) and the base plate (5) form a third oil chamber (13). When the first oil chamber (11) and the third oil chamber (13) are filled with oil at the same time, the second piston (7) simultaneously abuts against the end of the piston rod (2) and the positioning ring (4) to realize the centering and reset of the piston rod (2).

2. The centering oil cylinder of claim 1, wherein The end cap (3) has a first oil injection hole (30) communicating with the first oil chamber (11), the positioning ring (4) has a second oil injection hole (40) communicating with the second oil chamber (12), and the bottom plate (5) has a third oil injection hole (50) communicating with the third oil chamber (13).

3. The hydraulic cylinder for easy alignment according to claim 1, characterized in that, The contact surface between the second piston (7) and the hydraulic oil is larger than that between the first piston (6) and the hydraulic oil.

4. The centering oil cylinder of claim 1, wherein The distance between the end cap (3) and the positioning ring (4) is L1, the thickness of the first piston (6) is D1, the length of the piston rod (2) extending beyond the first piston (6) is L2, the thickness of the positioning ring (4) is D2, and L1-D1>L2-D2.

5. The centering oil cylinder of claim 1, wherein, The second oil chamber (12) is divided into two interconnected chambers by the positioning ring (4).

6. The centering oil cylinder of claim 1, wherein The piston rod (2) is coaxially and slidably sleeved within the end cap (3) and the positioning ring (4).

7. The centering oil cylinder of claim 1, wherein A hinged support (8) is provided on the base plate (5).

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