A high sealing large hydraulic cylinder for marine vessels

Abstract

The application relates to a high-sealing large hydraulic oil cylinder for a marine ship, which comprises an oil cylinder body, a first oil port and a second oil port arranged on the oil cylinder body, a piston rod slidingly arranged in the inner wall of the oil cylinder body, a first piston and a second piston slidingly arranged at the end of the piston rod and a buffer assembly arranged between the first piston and the second piston, wherein the buffer assembly comprises a plurality of buffer blocks arranged on the first piston, a plurality of buffer grooves arranged on the second piston, an oil inlet assembly arranged on the buffer blocks and the buffer grooves and a sealing assembly driven by the oil inlet assembly, the sealing assembly comprises sealing rings arranged on the first piston and the second piston, the hydraulic oil exerts a radial outward pressure on the sealing rings on the first piston and the second piston through the sealing assembly, and the sealing property between the sealing rings and the inner wall of the oil cylinder body is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of hydraulic system technology, and more specifically to a large hydraulic cylinder with high sealing performance for marine vessels. Background Technology

[0002] A hydraulic cylinder is an energy conversion device that converts hydraulic energy into reciprocating linear motion mechanical energy. Its structure generally consists of a cylinder barrel, cylinder head, piston, piston rod, sealing device, and buffer device. Chinese patent CN205047571U discloses an improved sealed excavator hydraulic cylinder. The cylinder body and cylinder bottom are connected, and a piston rod with a piston is located inside the cylinder body. A pipe clamp is provided on the outer circumferential surface of the cylinder body to fix the oil pipe, which connects to an oil hole on a support sleeve located at the opening of the cylinder body. A sealing groove is provided on the inner side wall of the cylinder body, and an axial sealing ring is installed in the sealing groove, tightly fitted onto the piston. A guide sleeve is located at the middle position of the piston rod, and outer and inner sealing rings are provided on the inner and outer sides of the guide sleeve. This design is reasonable and simple in structure, saving on parts processing costs. The sealing rings are not easily worn, providing good sealing performance, improving product safety. It also has high material utilization, reduces oil circuit loss, and extends the service life of the hydraulic cylinder.

[0003] However, the inventors discovered that in actual use, due to the continuous movement of the piston within the cylinder, once the sealing ring on the piston is roughened, oil leakage will occur, thus failing to achieve the braking force required during operation. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a high-sealing large hydraulic cylinder for marine vessels. This cylinder reduces wear between the first and second pistons by engaging them for cushioning, and applies radial outward pressure to the sealing rings on the first and second pistons via a sealing assembly, thereby significantly improving the sealing performance between the sealing rings and the inner wall of the cylinder body.

[0005] The technical solution of the present invention is as follows:

[0006] A high-sealing large hydraulic cylinder for marine vessels includes a cylinder body and a first oil port and a second oil port disposed on the cylinder body. A piston rod is slidably disposed within the sealed inner wall of the cylinder body. A first piston and a second piston are slidably disposed at the end of the piston rod, and a buffer assembly is disposed between the two. The buffer assembly includes a plurality of buffer blocks disposed on the first piston and a plurality of buffer grooves formed on the second piston. Each buffer block and buffer groove is provided with an oil inlet assembly and a sealing assembly driven by the oil inlet assembly. The sealing assembly includes a sealing ring disposed on the first piston and the second piston. The buffer assembly is used to push the buffer blocks to engage with the buffer grooves while oil enters through the first oil port or the second oil port. The oil inlet assembly is used to allow oil to enter the second piston or the first piston while hydraulic oil pushes the first piston to engage with the second piston or pushes the second piston to engage with the first piston. The sealing assembly is used to apply radial outward pressure to the sealing ring after the hydraulic oil enters the second piston or the first piston.

[0007] As a preferred embodiment, the buffer assembly further includes a first channel and a second channel formed in the middle of the buffer block, and a spring fixedly connected between the buffer groove and the first piston. The buffer block and the buffer groove cooperate, and the first channel and the second channel are spaced apart.

[0008] As a preferred embodiment, the oil inlet assembly includes an oil inlet groove fixedly formed on the first piston and the second piston, a plurality of connecting plates fixedly formed on the oil inlet groove, a baffle plate slidably formed in the oil inlet groove, a slide rod slidably formed on the first piston and the second piston, a limiting plate fixedly formed on the oil inlet groove, and an inclined groove fixedly formed on the inner side of the oil inlet groove. The two baffle plates are respectively fixedly formed at both ends of the slide rod, and the slide rod is configured as a telescopic structure.

[0009] As a preferred embodiment, the sealing assembly further includes an outer piston sleeve fixedly disposed within the first piston and the second piston, a plurality of cavities formed on one side of the outer piston sleeve, a plurality of oil outlet holes formed on the outer piston sleeve, an inner piston sleeve fixedly disposed within the outer piston sleeve, a plurality of connecting blocks fixedly disposed on the inner piston sleeve, and a flow channel formed in the middle of the connecting blocks. The flow channel on the first piston is connected to a first channel, the first channel is matched with a cavity on the second piston, the second channel is connected to a cavity on the first piston, the flow channel on the second piston is matched with a second channel, the connecting blocks are spaced apart from the cavities, and the inclined groove is connected to the flow channel.

[0010] As a preferred embodiment, both the first piston and the second piston are provided with annular grooves, the sealing ring is sleeved on the annular grooves, and an oil storage cavity is provided between the annular grooves and the outer piston sleeve.

[0011] As a preferred embodiment, a receiving cavity is provided between the outer piston sleeve and the inner piston sleeve, and there is a gap between the inner wall of the outer piston sleeve and the outer wall of the inner piston sleeve.

[0012] As a preferred embodiment, the first piston and the second piston are provided with sealing gaskets.

[0013] As a preferred embodiment, the flow channel diameter of the connecting block on the second piston is larger than the diameter of the second channel and the first channel on the first piston.

[0014] As a preferred embodiment, the limiting plate is provided with a rubber pad.

[0015] As a preferred embodiment, the diameter of the oil outlet hole is set between 2-4 mm.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. The present invention provides a buffer assembly, which reduces the number of times each piston rubs against the inner wall of the cylinder body by means of a first piston and a second piston, so that the two pistons alternately complete the rapid friction with the inner wall of the cylinder body due to acceleration, thereby extending its service life.

[0018] 2. The present invention also includes an oil inlet assembly and a sealing assembly. Oil is introduced through the first oil port, which applies radially outward pressure to the sealing ring on the second piston. Oil is introduced through the second oil port, which applies radially outward pressure to the sealing ring on the first piston. This dual protection of the cylinder body greatly improves the sealing performance.

[0019] In summary, the present invention has the advantages of good sealing effect and low wear, and is suitable for the field of hydraulic system technology. Attached Figure Description

[0020] The invention will be further described below with reference to the accompanying drawings:

[0021] Figure 1 This is a schematic diagram of the structure of a large hydraulic cylinder with high sealing for marine vessels;

[0022] Figure 2 This is a schematic diagram of the structure of the first piston and the second piston;

[0023] Figure 3 This is a schematic diagram of the structure of the buffer assembly and the oil inlet assembly;

[0024] Figure 4 This is a schematic diagram of the sealing assembly.

[0025] Figure 5 This is a schematic diagram of the outer piston sleeve and the inner piston sleeve.

[0026] Figure 6 This is a structural diagram of the cavity and connecting block;

[0027] Figure 7 This is a schematic diagram of the cross-sectional structure of the first and second pistons;

[0028] Figure 8 for Figure 7 Enlarged view of point A in the middle;

[0029] Figure 9 A schematic diagram showing the state when hydraulic oil pushes the second piston to engage with the first piston.

[0030] Figure 10 for Figure 9 Enlarged view at point B in the middle;

[0031] Figure 11 This is a schematic diagram showing the state of hydraulic oil entering the first piston and pressurizing the sealing ring.

[0032] Figure 12 for Figure 11 Enlarged view at point C;

[0033] Reference numerals in the attached drawings: 1. Cylinder body; 2. First oil port; 3. Second oil port; 4. Piston rod; 5. First piston; 6. Second piston; 7. Buffer assembly; 71. Buffer block; 72. Buffer groove; 73. First channel; 74. Second channel; 75. Spring; 8. Oil inlet assembly; 81. Oil inlet groove; 82. Connecting plate; 83. Baffle; 84. Slide rod; 85. Limiting plate; 86. Inclined groove; 9. Sealing assembly; 91. Sealing ring; 92. Outer piston sleeve; 93. Cavity; 94. Oil outlet; 95. Inner piston sleeve; 96. Connecting block; 97. Flow channel; 10. Annular groove; 11. Oil storage chamber; 12. Receiving chamber; 13. Sealing gasket. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0035] Example 1

[0036] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0037] like Figure 1 and Figure 12As shown, a high-sealing large hydraulic cylinder for marine vessels includes a cylinder body 1 and a first oil port 2 and a second oil port 3 disposed on the cylinder body 1. A piston rod 4 is slidably disposed within the sealed inner wall of the cylinder body 1. A first piston 5 and a second piston 6 are slidably disposed at the end of the piston rod 4, and a buffer assembly 7 is disposed between the two. The buffer assembly 7 includes a plurality of buffer blocks 71 disposed on the first piston 5 and a plurality of buffer grooves 72 formed on the second piston 6. An oil inlet assembly 8 is disposed on each of the buffer blocks 71 and the buffer grooves 72, and a sealing assembly 9 driven by the oil inlet assembly 8 is disposed on each of the buffer blocks 71 and the buffer grooves 72. The sealing assembly 9 includes a plurality of oil inlet components disposed on the first piston 5 and the second piston 6. The sealing rings 91 on the first piston 5 and the second piston 6, the buffer assembly 7 is used to push the buffer block 71 to engage with the buffer groove 72 while oil enters the first oil port 2 or the second oil port 3, the oil inlet assembly 8 is used to allow oil to enter the second piston 6 or the first piston 5 while hydraulic oil pushes the first piston 5 to engage with the second piston 6 or pushes the second piston 6 to engage with the first piston 5, and the sealing assembly 9 is used to apply radial outward pressure to the sealing ring 91 after the hydraulic oil enters the second piston 6 or the first piston 5. The piston rod 4 is provided with a sliding groove, and the first piston 5 and the second piston 6 are simultaneously slidably disposed in the sliding groove by a slider.

[0038] It is worth mentioning that, such as Figure 9 and Figure 10As shown, the buffer assembly 7 also includes a first channel 73 and a second channel 74 formed in the middle of the buffer block 71, and a spring 75 fixedly connected between the buffer groove 72 and the first piston 5. The buffer block 71 and the buffer groove 72 cooperate, and the first channel 73 and the second channel 74 are spaced apart. Since a product to be driven is connected to one end of the piston rod 4, the resistance of the first piston 5 near the piston rod 4 is relatively large. In use, the first piston 5 and the second piston 6 are connected through the buffer block 71, the spring 75, and the buffer groove 72, so that the first piston 5 and the second piston 6 always maintain a set distance. When the cylinder starts moving from rest, the hydraulic oil needs to overcome inertia and friction, resulting in a brief acceleration process, followed by a stable speed. Therefore, when oil enters through the second oil port 3, due to the large resistance at the first piston 5, the hydraulic oil will push the second piston 6 and the first piston 5 to slide simultaneously until the first piston 5 slides to the end of the groove and then remains stationary. The second piston 6 continues to slide and compress the spring 75, causing the buffer block 71 to engage with the buffer groove 72. The second piston 6 then comes into contact with the first piston 5. Subsequently, the second piston 6 and the first piston 5 push the piston rod 4 to slide until the first piston 5 slides to the end inside the cylinder body 1. At this point, when the piston rod 4 needs to slide in the opposite direction, oil needs to enter through the first oil port 2 and the pressure needs to be released through the second oil port 3. Therefore, under the action of the spring 75, the second piston 6 disengages from the first piston 5. Then, the hydraulic oil pushes the first piston 5 and the second piston 6 to slide simultaneously until the second piston 6 slides to the end of the groove and remains stationary. The first piston 5 continues to slide and compresses the spring 75 until the buffer groove 72 engages with the buffer block 71, and the first piston 5 comes into contact with the second piston 6. This method can reduce the number of times the first piston 5 and the second piston 6 rub against the inner wall of the cylinder body 1, allowing the two pistons to alternately complete the rapid friction caused by acceleration against the inner wall of the cylinder body 1, thus extending their service life.

[0039] It needs to be emphasized that, such as Figure 11 and Figure 12As shown, the oil inlet assembly 8 includes an oil inlet groove 81 fixedly opened on the first piston 5 and the second piston 6, several connecting plates 82 fixedly installed on the oil inlet groove 81, baffles 83 slidably installed in the oil inlet groove 81, a sliding rod 84 slidably installed on the first piston 5 and the second piston 6, a limiting plate 85 fixedly installed on the oil inlet groove 81, and an inclined groove 86 fixedly opened on the inner side of the oil inlet groove 81. The two baffles 83 are respectively fixedly installed at both ends of the sliding rod 84, and the sliding rod 84 is configured as a telescopic structure. A spring is installed inside the sliding rod 84. In use, when oil enters through the second oil port 3, the hydraulic oil pushes the second piston 6 and the first piston 5 to slide simultaneously, and the two baffles 83 also slide simultaneously. Subsequently, when the first piston 6 enters through the second oil port 3, the hydraulic oil pushes the second piston 6 and the first piston 5 to slide simultaneously. After piston 5 remains stationary, during the process of the second piston 6 engaging with the first piston 5, the baffle 83 at the second piston 6 slides along the slide rod 84, causing the baffle 83 at the first piston 5 to move until it reaches the limiting plate 85 for a stop. The oil inlet groove 81 of the first piston 5 is then closed. At this point, the second piston 6 engages with the first piston 5, and the hydraulic oil pushes the baffle 83 at the second piston 6 to continue sliding to the inclined groove 86. The slide rod 84 retracts, and the hydraulic oil at the second piston 6 enters the first piston 5 through the oil inlet groove 81 and the inclined groove 86. This causes the hydraulic oil to apply radial outward pressure to the sealing ring 91 on the first piston 5, increasing the pressure between the sealing ring 91 and the oil. The sealing between the inner walls of cylinder body 1 is ensured. Conversely, when piston rod 4 needs to slide in the opposite direction, oil enters through first oil port 2, and pressure is released through second oil port 3. At the same time, the spring in slide rod 84 pops out and resets the baffle 83 at the second piston 6, causing the baffle 83 to slide to the oil inlet groove 81 for sealing. Subsequently, hydraulic oil pushes the first piston 5 and the second piston 6 to slide simultaneously until the second piston 6 remains stationary. During the contact process between the first piston 5 and the second piston 6, the baffle 83 at the first piston 5 drives the baffle 83 at the second piston 6 to slide through slide rod 84 until the baffle 83 at the second piston 6 moves to the limiting plate 85 for limiting, and the oil inlet groove 81 of the second piston 6 is closed. In this state, the first piston 5 and the second piston 6 are in contact. Therefore, the hydraulic oil pushes the baffle 83 at the first piston 5 to continue sliding to the inclined groove 86, and the slide rod 84 retracts. At this time, the hydraulic oil at the first piston 5 enters the second piston 6 through the oil inlet groove 81 and the inclined groove 86, so that the hydraulic oil applies radial outward pressure to the sealing ring 91 on the second piston 6, improving the sealing performance between the sealing ring 91 and the inner wall of the cylinder body 1. When oil enters through the first oil port 2, radial outward pressure is applied to the sealing ring 91 on the second piston 6. When oil enters through the second oil port 3, radial outward pressure is applied to the sealing ring 91 on the first piston 5. This dual protection of the cylinder body 1 greatly improves the sealing performance.

[0040] It should be further explained that, such as Figure 11 and Figure 12As shown, the sealing assembly 9 also includes an outer piston sleeve 92 fixedly disposed within the first piston 5 and the second piston 6, a plurality of cavities 93 formed on one side of the outer piston sleeve 92, a plurality of oil outlet holes 94 formed on the outer piston sleeve 92, an inner piston sleeve 95 fixedly disposed within the outer piston sleeve 92, a plurality of connecting blocks 96 fixedly disposed on the inner piston sleeve 95, and a flow channel 97 formed in the middle of the connecting blocks 96. The flow channel 97 on the first piston 5 is connected to the first channel 73, the first channel 73 is matched with the cavity 93 on the second piston 6, the second channel 74 is connected to the cavity 93 on the first piston 5, the flow channel 97 on the second piston 6 is matched with the second channel 74, the connecting blocks 96 are spaced apart from the cavities 93, and the inclined groove 86 is connected to the flow channel 97. In use, when hydraulic oil enters from the oil inlet of the first piston 5... The oil flows from groove 81 and inclined groove 86 into the inner piston sleeve 95, and through connecting block 96, flow channel 97 and first channel 73 into the cavity 93 of the second piston 6. From the cavity 93, it flows between the outer piston sleeve 92 and the inner piston sleeve 95, and finally flows out from the oil outlet 94, generating radial outward pressure on the sealing ring 91 of the second piston 6, thus improving the sealing effect of the sealing ring 91. Conversely, when hydraulic oil flows from the oil inlet groove 81 and inclined groove 86 of the second piston 6 into the inner piston sleeve 95, and through connecting block 96, flow channel 97 and second channel 74 into the cavity 93 of the first piston 5, and from the cavity 93 into the space between the outer piston sleeve 92 and the inner piston sleeve 95, and finally flows out from the oil outlet 94, it generates radial outward pressure on the sealing ring 91 of the first piston 5, thus improving the sealing effect of the sealing ring 91.

[0041] It is worth mentioning that, such as Figure 8 As shown, annular grooves 10 are provided on both the first piston 5 and the second piston 6. A sealing ring 91 is fitted on the annular groove 10. An oil storage chamber 11 is provided between the annular groove 10 and the outer piston sleeve 92. Hydraulic oil flows into the oil storage chamber 11 from the cavity 93, generating radial outward pressure on the sealing ring 91.

[0042] Furthermore, such as Figure 8 As shown, a receiving cavity 12 is provided between the outer piston sleeve 92 and the inner piston sleeve 95, and there is a gap between the inner wall of the outer piston sleeve 92 and the outer wall of the inner piston sleeve 95, so that oil can flow from the receiving cavity 12 into the oil storage cavity 11 for pressurization.

[0043] In addition, such as Figure 4 As shown, sealing gaskets 13 are provided on the first piston 5 and the second piston 6 to improve the sealing performance after the two pistons are in contact.

[0044] Furthermore, such as Figure 8 As shown, the diameter of the flow channel 97 of the connecting block 96 on the second piston 6 is larger than the diameter of the second channel 74 and the first channel 73 on the first piston 5, allowing the oil to flow better between the two.

[0045] Among them, such as Figure 8 As shown, a rubber pad is provided on the limiting plate 85 to reduce the friction between the baffle 83 and the limiting plate 85 and extend the service life.

[0046] In addition, such as Figure 6 As shown, the diameter of the oil outlet 94 is set between 2-4 mm.

[0047] Work process

[0048] When oil enters through the second oil port 3, the hydraulic oil pushes the second piston 6 and the first piston 5 to slide simultaneously, and the two baffles 83 also slide simultaneously, reaching a relatively stationary state. Subsequently, after the first piston 5 remains stationary, during the process of the second piston 6 and the first piston 5 being in contact, the baffle 83 at the second piston 6 drives the baffle 83 at the first piston 5 to slide through the slide rod 84 until the baffle 83 at the first piston 5 moves to the limiting plate 85 for limitation, and the oil inlet groove 81 of the first piston 5 is in a closed state. At this time, the second piston 6 is in contact with the first piston 5, so the hydraulic oil pushes the baffle 83 at the second piston 6 to continue sliding to the inclined groove 86, and the slide rod 84 retracts. Hydraulic oil at the second piston 6 enters the first piston 5 through the inlet groove 81 and the inclined groove 86, causing the hydraulic oil to exert radial outward pressure on the sealing ring 91 on the first piston 5, thereby improving the sealing performance between the sealing ring 91 and the inner wall of the cylinder body 1. When the hydraulic oil flows from the inlet groove 81 and the inclined groove 86 of the first piston 5 into the inner piston sleeve 95, and then flows into the cavity 93 at the second piston 6 through the connecting block 96, the flow channel 97 and the first channel 73, and then flows from the cavity 93 into the space between the outer piston sleeve 92 and the inner piston sleeve 95, and finally flows out from the outlet hole 94, it generates radial outward pressure on the sealing ring 91 at the second piston 6, thereby improving the sealing effect of the sealing ring 91.

[0049] In the description of this invention, it should be understood that the terms "front and back", "left and right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0050] Of course, those skilled in the art should understand that the term "a" should be understood as "at least one" or "one or more". That is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple. The term "a" should not be understood as a limitation on the quantity.

[0051] The above description, in conjunction with the accompanying drawings, is merely a preferred embodiment of the present invention. However, the present invention is not limited to the above-described embodiments. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention. These modifications and improvements should also be considered within the scope of protection of the present invention and will not affect the effectiveness and practicality of the present invention.

Claims

1. A large hydraulic cylinder with high sealing performance for marine vessels, comprising a cylinder body (1) and a first oil port (2) and a second oil port (3) disposed on the cylinder body (1), characterized in that: A piston rod (4) is slidably disposed within the sealed inner wall of the cylinder body (1). A first piston (5) and a second piston (6) are slidably disposed at the end of the piston rod (4), and a buffer assembly (7) is disposed between the two. The buffer assembly (7) includes several buffer blocks (71) disposed on the first piston (5), several buffer grooves (72) opened on the second piston (6), and a first channel (73) and a second channel (74) opened in the middle of the buffer blocks (71). An oil inlet assembly (8) and a sealing assembly (9) driven by the oil inlet assembly (8) are disposed on both the buffer blocks (71) and the buffer grooves (72). The oil inlet assembly (8) includes an oil inlet groove (81) fixedly opened on the first piston (5) and the second piston (6). The sealing assembly (9) includes a sealing ring (91) provided on the first piston (5) and the second piston (6), an outer piston sleeve (92) fixedly provided in the first piston (5) and the second piston (6), a plurality of cavities (93) provided on one side of the outer piston sleeve (92), a plurality of oil outlet holes (94) provided on the outer piston sleeve (92), an inner piston sleeve (95) fixedly provided in the outer piston sleeve (92), a plurality of connecting blocks (96) fixedly provided on the inner piston sleeve (95), and a flow channel (97) provided in the middle of the connecting blocks (96). The flow channel (97) on the first piston (5) is connected to the first channel (73). The second piston (5) and the second piston (6) are connected to the cavity (93). The flow channel (97) on the second piston (6) is connected to the second channel (74). The connecting block (96) is spaced apart from the cavity (93). The inclined groove (86) is connected to the flow channel (97). The first piston (5) and the second piston (6) are both provided with annular grooves (10). The sealing ring (91) is sleeved on the annular groove (10). An oil storage cavity (11) is provided between the annular groove (10) and the outer piston sleeve (92). A receiving cavity (12) is provided between the outer piston sleeve (92) and the inner piston sleeve (95). The inner wall of the outer piston sleeve (92) is connected to the inner piston. There is a gap between the outer walls of the sleeve (95). The diameter of the flow channel (97) of the connecting block (96) on the second piston (6) is larger than the diameter of the second channel (74) and the first channel (73) on the first piston (5). The buffer assembly (7) is used to push the buffer block (71) and the buffer groove (72) to engage while oil is entering the first oil port (2) or the second oil port (3). The oil inlet assembly (8) is used to allow oil to enter the second piston (6) or the first piston (5) while hydraulic oil pushes the first piston (5) to engage with the second piston (6) or pushes the second piston (6) to engage with the first piston (5). The sealing assembly (9) is used to apply radial outward pressure to the sealing ring (91) after the hydraulic oil enters the second piston (6) or the first piston (5).

2. A large hydraulic cylinder with high sealing performance for marine vessels according to claim 1, characterized in that: The buffer assembly (7) also includes a spring (75) fixedly connected between the buffer groove (72) and the first piston (5), the buffer block (71) cooperates with the buffer groove (72), and the first channel (73) and the second channel (74) are spaced apart.

3. A large hydraulic cylinder with high sealing performance for marine vessels according to claim 1, characterized in that: The oil inlet assembly (8) also includes several connecting plates (82) fixedly disposed on the oil inlet groove (81), baffles (83) slidably disposed in the oil inlet groove (81), slide rods (84) slidably disposed on the first piston (5) and the second piston (6), and limiting plates (85) fixedly disposed on the oil inlet groove (81). The two baffles (83) are respectively fixedly disposed at both ends of the slide rods (84), and the slide rods (84) are configured as telescopic structures.

4. A large hydraulic cylinder with high sealing performance for marine vessels according to claim 1, characterized in that: Sealing gaskets (13) are provided on the first piston (5) and the second piston (6).

5. A large hydraulic cylinder with high sealing performance for marine vessels according to claim 3, characterized in that: A rubber pad is provided on the limiting plate (85).

6. A large hydraulic cylinder with high sealing performance for marine vessels according to claim 1, characterized in that: The diameter of the oil outlet (94) is set between 2-4 mm.

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