hydraulic cylinder

Abstract

The hydraulic cylinder belongs to the technical field of hydraulic drive, and comprises a cylinder body, a piston assembly and a pressure control assembly. The piston assembly is movably arranged in the cylinder body, and the piston assembly and the cylinder body define a first sealed cavity, a second sealed cavity and a third sealed cavity. The pressure control assembly is arranged outside the cylinder body and connected with the cylinder body. The pressure control assembly is in communication with the third sealed cavity. When the piston assembly is extended or retracted, the pressure control assembly applies an action force to the piston assembly through the third sealed cavity. The action force is the reaction force of the water pressure pressure that the piston assembly is subjected to when being extended or retracted. The hydraulic cylinder can improve the control accuracy of deep-sea equipment.

Description

Technical Field

[0001] This disclosure belongs to the field of hydraulic drive technology, and specifically relates to a hydraulic cylinder. Background Technology

[0002] As humanity's exploration of the deep sea deepens, the demands on deep-sea equipment are becoming increasingly stringent. Deep-sea equipment not only needs to operate stably in environments characterized by high pressure, low temperature, and abundant corrosive media, but also needs to be able to perform complex actions.

[0003] In related technologies, various parts of deep-sea equipment are connected to the piston rods of different hydraulic cylinders. By controlling the extension and retraction of different hydraulic cylinders, the parts of the deep-sea equipment connected to the hydraulic cylinders can be controlled to enable the deep-sea equipment to perform different actions.

[0004] However, when the hydraulic cylinder extends and retracts underwater, the piston rod is affected by seawater pressure. In particular, changes in water pressure caused by variations in seawater depth can severely impact the actual output power and control accuracy of the hydraulic cylinder, thereby affecting the control precision of deep-sea equipment. Summary of the Invention

[0005] This disclosure provides a hydraulic cylinder that can automatically adapt to changes in seawater depth. The actual output power and control accuracy of the hydraulic cylinder are not affected by seawater depth, thereby improving the control accuracy of deep-sea equipment. The technical solution is as follows:

[0006] This disclosure provides a hydraulic cylinder, which includes a cylinder body, a piston assembly, and a pressure control assembly. The piston assembly is movably located within the cylinder body, and the piston assembly and the cylinder body define a first sealing cavity, a second sealing cavity, and a third sealing cavity. When the pressure in the first sealing cavity is greater than the pressure in the second sealing cavity, the piston assembly moves toward the interior of the cylinder body; when the pressure in the first sealing cavity is less than the pressure in the second sealing cavity, the piston assembly extends out of the cylinder body. The pressure control assembly is located outside the cylinder body and connected to the cylinder body. The pressure control assembly communicates with the third sealing cavity. The pressure control assembly is configured to apply a force to the piston assembly through the third sealing cavity during extension and retraction, the force being the reaction force of the water pressure experienced by the piston assembly during extension and retraction.

[0007] In another implementation of this disclosure, the cylinder body includes an outer cylinder sleeve and an inner central sleeve, the inner central sleeve being located inside the outer cylinder sleeve, and a first end of the inner central sleeve being connected to a first end of the outer cylinder sleeve, forming an annular space between the inner central sleeve and the outer cylinder sleeve; the piston assembly includes an outer sleeve and a piston, the outer sleeve being coaxially sleeved outside the piston, and a first end of the outer sleeve being sealed to the piston, the second end of the outer sleeve being movably located within the annular space, and being sealed to the inner wall of the outer cylinder sleeve and the outer wall of the inner central sleeve respectively; a first sealing cavity is defined between the second end of the outer sleeve, the outer wall of the outer sleeve, and the inner wall of the outer cylinder sleeve, a second sealing cavity is defined between the inner wall of the outer sleeve, the piston, and the inner wall of the inner central sleeve, and a third sealing cavity is defined between the second end of the outer sleeve, the inner wall of the outer cylinder sleeve, and the outer wall of the inner central sleeve.

[0008] In another implementation of this disclosure, the end face area of ​​the second end of the outer sleeve is equal to the sum of the end face area of ​​the first end of the outer sleeve and the end face area of ​​the first end of the piston.

[0009] In another implementation of this disclosure, the outer sleeve includes an outer cylinder and a sealing ring platform. The sealing ring platform is sealed around the first end of the outer cylinder and connected to the outer cylinder. The first end of the outer cylinder is movably located in the annular space, and the second end of the outer cylinder is located outside the cylinder body.

[0010] In another implementation of this disclosure, the piston assembly further includes a piston rod, a first end of which is connected to the piston, the piston rod being coaxially located within the outer cylinder, and a second end of which is movably located within the inner central sleeve; the piston rod has an internal mounting space for mounting a displacement sensor.

[0011] In another implementation of this disclosure, the difference between the cross-sectional area of ​​the piston and the cross-sectional area of ​​the piston rod is equal to the end face area of ​​the sealing ring platform.

[0012] In another implementation of this disclosure, the hydraulic cylinder further includes a protective cover located outside the outer cylinder sleeve and connected to one end of the outer cylinder sleeve. A sealed space is formed between the protective cover and the end face of the outer cylinder sleeve. The sealed space is connected to the mounting space, and the displacement sensor is located in the sealed space and the mounting space.

[0013] In another implementation of this disclosure, the pressure control component includes a flexible container filled with oil. The flexible container is deformable under water pressure and, after deformation, can drive the oil inside into the third sealed cavity.

[0014] In another implementation of this disclosure, the flexible container is an annular structure, and the flexible container is fitted over the cylinder body.

[0015] In another implementation of this disclosure, the outer cylinder liner includes a cylinder head, a cylinder barrel, and a cylinder bottom. The cylinder head is connected to a first end of the cylinder barrel and is fitted over the outer sleeve. The cylinder bottom is connected to a second end of the cylinder barrel and is connected to the inner center sleeve.

[0016] The beneficial effects of the technical solutions provided in this disclosure are:

[0017] Because the hydraulic cylinder also includes a pressure control component, and this component is connected to the third sealing chamber, the pressure control component is configured to apply a force to the piston assembly through the third sealing chamber during piston assembly extension and retraction. This force is the reaction force of the water pressure experienced by the piston assembly during extension and retraction. This ensures that the piston assembly is not affected by water pressure during movement, stabilizes output power, and improves the control accuracy of deep-sea equipment. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the external structure of a hydraulic cylinder provided in an embodiment of this disclosure;

[0020] Figure 2 This is a schematic diagram of the axial cross-sectional structure of a hydraulic cylinder provided in an embodiment of this disclosure;

[0021] Figure 3 This is a schematic diagram of a hydraulic cylinder in the maximum extension displacement according to an embodiment of the present disclosure;

[0022] Figure 4 This is a schematic diagram of a hydraulic cylinder in a retracted state according to an embodiment of this disclosure;

[0023] Figure 5 This is a schematic diagram of a partial cross-section of a piston assembly provided in an embodiment of this disclosure;

[0024] Figure 6 This is a schematic diagram of a piston assembly after partial cross-section according to an embodiment of the present disclosure;

[0025] Figure 7This is a schematic diagram of the structure of a hydraulic cylinder connected to a directional valve according to an embodiment of this disclosure.

[0026] The symbols in the diagram represent the following meanings:

[0027] 1. Cylinder block; 11. Outer cylinder liner; 12. Inner center sleeve; 120. Annular space; 111. Cylinder head; 1111. Insertion section; 1112. Limiting flange; 112. Cylinder barrel; 113. Cylinder bottom; 1131. Connecting section; 1132. Positioning ring; 101. First oil port; 102. Second oil port; 103. Third oil port; 14. Connecting arm;

[0028] 2. Piston assembly; 201. First sealing cavity; 2011. First annular surface; 202. Second sealing cavity; 2021. Second annular surface; 203. Third sealing cavity; 2031. Third annular surface; 21. Outer sleeve; 22. Piston; 211. Outer cylinder; 212. Sealing ring platform; 23. Piston rod; 230. Installation space; 24. Displacement sensor; 241. Fixing head; 242. Detection rod; 243. Magnetic ring; 26. Connector;

[0029] 3. Pressure control components; 31. Flexible containers;

[0030] 4. Protective cover; 40. Sealed space; 41. Watertight plug;

[0031] 100. Reversing valve. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0033] This disclosure provides a hydraulic cylinder, such as... Figure 1 As shown, the hydraulic cylinder includes a cylinder body 1, a piston assembly 2, and a pressure control assembly 3.

[0034] Figure 2 This is a schematic diagram of the axial cross-sectional structure of a hydraulic cylinder provided in an embodiment of this disclosure, combined with... Figure 2 The piston assembly 2 is movably located within the cylinder body 1, and the piston assembly 2 and the cylinder body 1 define a first sealing cavity 201, a second sealing cavity 202, and a third sealing cavity 203. When the pressure exerted on the piston assembly 2 by the first sealing cavity 201 is greater than the pressure exerted on the piston assembly 2 by the second sealing cavity 202, the piston assembly 2 moves toward the interior of the cylinder body 1. When the pressure exerted on the piston assembly 2 by the first sealing cavity 201 is less than the pressure exerted on the piston assembly 2 by the second sealing cavity 202, the piston assembly 2 extends out of the cylinder body 1.

[0035] The pressure control component 3 is located outside the cylinder body 1 and connected to the cylinder body 1. The pressure control component 3 is connected to the third sealing cavity 203. The pressure control component 3 is configured to apply a force to the piston assembly 2 through the third sealing cavity 203 when the piston assembly 2 extends or retracts. The force is the reaction force of the water pressure that the piston assembly 2 experiences when it extends or retracts.

[0036] When the hydraulic cylinder provided in this embodiment is placed underwater for operation, such as driving deep-sea equipment in seawater, the cylinder includes a cylinder body 1 and a piston assembly 2. Therefore, the cylinder body 1 can provide a mounting base for the piston assembly 2. Simultaneously, the piston assembly 2 is movably located within the cylinder body 1, and the piston assembly 2 and the cylinder body 1 define a first sealing cavity 201 and a second sealing cavity 202. When the pressure exerted on the piston assembly 2 by the first sealing cavity 201 is greater than the pressure exerted on the piston assembly 2 by the second sealing cavity 202, the piston assembly 2 moves towards the interior of the cylinder body 1. When the pressure exerted on the piston assembly 2 by the first sealing cavity 201 is less than the pressure exerted on the piston assembly 2 by the second sealing cavity 202, the piston assembly 2 extends out of the cylinder body 1. Thus, by filling the first sealing cavity 201 or the second sealing cavity 202 with oil, the piston assembly 2 can extend and retract, thereby driving the deep-sea equipment.

[0037] Since the hydraulic cylinder also includes a pressure control component 3, and the pressure control component 3 is connected to the third sealing cavity 203, the pressure control component 3 is configured to apply a force to the piston assembly 2 through the third sealing cavity 203 during piston assembly 2 extension and retraction. This force is the reaction force of the water pressure experienced by the piston assembly 2 during extension and retraction. This ensures that the piston assembly 2 is not affected by water pressure during movement, stabilizes the output power, and improves the control accuracy of the deep-sea equipment.

[0038] Optionally, the cylinder body 1 includes an outer cylinder liner 11 and an inner central sleeve 12. The inner central sleeve 12 is located inside the outer cylinder liner 11, and the first end of the inner central sleeve 12 is connected to the first end of the outer cylinder liner 11, forming an annular space 120 between the inner central sleeve 12 and the outer cylinder liner 11. The piston assembly 2 includes an outer sleeve 21 and a piston 22. The outer sleeve 21 is coaxially sleeved around the piston 22, and the first end of the outer sleeve 21 is sealed to the piston 22. The second end of the outer sleeve 21 is movably located within the annular space 120 and is sealed to the inner wall of the outer cylinder liner 11 and the outer wall of the inner central sleeve 12, respectively. A first sealing cavity 201 is defined between the second end of the outer sleeve 21, the outer wall of the outer sleeve 21, and the inner wall of the outer cylinder sleeve 11; a second sealing cavity 202 is defined between the inner wall of the outer sleeve 21, the piston 22, and the inner wall of the inner center sleeve 12; and a third sealing cavity 203 is defined between the second end of the outer sleeve 21, the inner wall of the outer cylinder sleeve 11, and the outer wall of the inner center sleeve 12.

[0039] In the above implementation, the piston assembly 2 is configured as an outer sleeve 21 and a piston 22, and the cylinder body 1 is configured as an outer cylinder sleeve 11 and an inner central sleeve 12. This allows the piston assembly 2 and the cylinder body 1 to be configured as a double-layer structure, thereby forming a first sealing cavity 201 between the outer sleeve 21 and the outer cylinder sleeve 11, a third sealing cavity 203 between the outer sleeve 21, the inner central sleeve 12, and the outer cylinder sleeve 11, and a second sealing cavity 202 between the outer sleeve 21, the piston 22, and the inner central sleeve 12. In other words, the above structure can simply define the first sealing cavity 201, the second sealing cavity 202, and the third sealing cavity 203.

[0040] Optionally, the end face area of ​​the second end of the outer sleeve 21 is equal to the sum of the end face area of ​​the first end of the outer sleeve 21 and the end face area of ​​the first end of the piston 22.

[0041] In the above implementation, since the third sealing cavity 203 is defined by the second end of the outer sleeve 21, the inner wall of the outer cylinder liner 11, and the outer wall of the inner center sleeve 12, the effective area of ​​the third sealing cavity 203 on the outer sleeve 21 is actually the end face area of ​​the second end of the outer sleeve 21 (that is... Figure 1 The area S3 of the third annular surface 2031. After the piston assembly 2 extends, the area of ​​the water pressure acting on the piston assembly 2 is the sum of the end face area of ​​the first end of the outer sleeve 21 and the end face area of ​​the first end of the piston 22 (that is...). Figure 1 S4).

[0042] When the end face area S3 of the second end of the outer sleeve 21 is equal to the sum of the end face areas of the first end of the outer sleeve 21 and the first end of the piston 22 (S4), to ensure that the force exerted by the third sealing cavity 203 on the piston assembly 2 during the extension and retraction of the piston assembly 2 is equal to the force exerted by the water pressure on the piston assembly 2, it is only necessary to ensure that the oil pressure in the third sealing cavity 203 is equal to the water pressure. Therefore, the above arrangement ensures that as long as the oil pressure in the third sealing cavity 203 is equal to the water pressure, the third sealing cavity 203 can exert a force on the piston assembly 2 during the extension and retraction of the piston assembly 2 that is the reaction force of the water pressure experienced by the piston assembly 2 during the extension and retraction.

[0043] Optionally, the outer sleeve 21 includes an outer cylinder 211 and a sealing ring platform 212, the sealing ring platform 212 being sealed outside the first end of the outer cylinder 211 and connected to the outer cylinder 211.

[0044] The first end of the outer cylinder 211 is movably located in the annular cavity 120, and the first end of the outer cylinder 211 is located outside the cylinder body 1. Along the moving direction of the piston 22, the first sealing cavity 201 and the third sealing cavity 203 are located on opposite sides of the sealing ring platform 212, respectively.

[0045] In the above implementation, the outer sleeve 21 is configured as an outer cylinder body 211 and a sealing ring platform 212. This allows the outer sleeve 21 to be sealed and connected to the inner wall of the outer cylinder liner 11 and the outer wall of the inner center sleeve 12 through the sealing ring platform 212. At the same time, the outer cylinder body 211 isolates and separates the second sealing cavity 202 from the first sealing cavity 201.

[0046] In this embodiment, the outer cylinder 211 and the sealing ring platform 212 are integral structural components. This facilitates manufacturing and also makes it easy to achieve a sealed connection between the outer cylinder 211 and the sealing ring platform 212.

[0047] Figure 3 This is a schematic diagram of a hydraulic cylinder in the maximum extension displacement according to an embodiment of this disclosure, combined with... Figure 3 When in use, when the pressure exerted by the second sealing chamber 202 on the piston assembly 2 is greater than the pressure exerted by the first sealing chamber 201 on the piston assembly 2, the oil in the second sealing chamber 202 can push the piston 22, causing the piston 22 to extend out of the cylinder 1 along with the outer cylinder 211, thus realizing the extension of the piston assembly 2.

[0048] Figure 4 This is a schematic diagram of a hydraulic cylinder in a retracted state according to an embodiment of this disclosure, combined with... Figure 4 When the pressure exerted by the first sealing chamber 201 on the piston assembly 2 is greater than the pressure exerted by the second sealing chamber 202 on the piston assembly 2, the oil in the first sealing chamber 201 can push the sealing ring platform 212, causing the sealing ring platform 212, along with the outer cylinder 211, to move toward the interior of the cylinder 1 and gradually retract into the cylinder 1.

[0049] Combination Figures 2 to 4 Since the third sealing cavity 203 and the first sealing cavity 201 are located on opposite sides of the sealing ring platform 212, when the piston assembly 2 extends out of the cylinder body 1, the piston assembly 2 will be subject to water pressure resistance. At this time, the third sealing cavity 203 can provide a force towards the sealing ring platform 212. Figure 1 The force acting to the left counteracts the water pressure. When the piston assembly 2 moves toward the inside of the cylinder 1 and retracts into the cylinder 1, the part of the piston assembly 2 that extends out of the cylinder 1 will be pushed by the water pressure, helping it to retract into the cylinder 1. At this time, the third sealing cavity 203 can provide a force to the sealing ring platform 212 that hinders the movement of the sealing ring platform 212, thereby counteracting the water pressure.

[0050] In this embodiment, to achieve a sealed connection between the sealing ring platform 212, the inner central sleeve 12, and the outer cylinder sleeve 11, the inner wall of the outer cylinder 211 has multiple sealing ring grooves spaced apart along the axis of the outer cylinder 211. The outer wall of the sealing ring platform 212 has multiple sealing ring grooves spaced apart along the axial direction of the sealing ring platform 212. A sealing ring is installed in each sealing ring groove.

[0051] Optionally, the piston assembly 2 further includes a piston rod 23, the first end of which is connected to the piston 22. The piston rod 23 is coaxially located in the outer cylinder 211, and the second end of the piston rod 23 is movably located in the inner central sleeve 12. The piston rod 23 has an internal mounting space 230 for mounting a displacement sensor.

[0052] In the above implementation, the piston rod 23 is used to mount a displacement sensor so that the extension and retraction stroke of the piston assembly 2 can be detected in real time through the displacement sensor.

[0053] Optionally, the hydraulic cylinder also includes a protective cover 4, which is located outside the outer cylinder sleeve 11 and connected to one end of the outer cylinder sleeve 11. A sealed space 40 is formed between the protective cover 4 and the end face of the outer cylinder sleeve 11. The sealed space 40 is connected to the installation space 230, and the displacement sensor is located in the sealed space 40 and the installation space 230.

[0054] In the above implementation, the protective cover 4 can protect the displacement sensor, isolate the displacement sensor from seawater, and avoid the influence of seawater on the displacement sensor.

[0055] It is understandable that a watertight plug 41 can be inserted into the protective cover 4. The watertight plug 41 is installed and fixed on the side wall of the protective cover 4. The watertight plug 41 is used to electrically connect to the cable connector of the displacement sensor 24.

[0056] In this embodiment, the mounting space 230 is a strip-shaped hole, and its extension direction is the axial direction of the piston rod 23. The displacement sensor 24 is a magnetostrictive sensor. The displacement sensor 24 includes a fixed head 241, a detection rod 242, and a magnetic ring 243. The fixed head 241 is located in the sealed space 40 and connected to the end of the outer cylinder liner 11. The detection rod 242 is located in the coaxial mounting space 230. The magnetic ring 243 is located inside the piston rod 23 and coaxially connected to it. The magnetic ring 243 is sleeved on the outside of the detection rod 242 and is not in contact with it. Thus, the displacement sensor 24 can be positioned through the sealed space 40 and the mounting space 230. The magnetic ring 243 moves with the piston rod 23. The detection rod 242 detects the position of the magnetic ring 243, thereby monitoring the position of the piston rod 23 in real time and obtaining the displacement of the piston 22.

[0057] Combination Figures 1 to 4In this embodiment, both the piston 22 and the piston rod 23 have circular cross-sections. The annular surface corresponding to the difference between the cross-section of the piston 22 and the cross-section of the piston rod 23 is the second annular surface 2021. Figure 1 (S2 in the middle). The end face area S1 of the sealing ring platform 212 is equal to the area S2 of the second ring surface 2021.

[0058] In the above implementation, the difference S2 between the cross-sectional area of ​​piston 22 and the cross-sectional area of ​​piston rod 23 is equal to the annular surface area S1 of sealing ring platform 212. This ensures that the area of ​​action of the first sealing cavity 201 on piston assembly 2 is the same as the area of ​​action of the second sealing cavity 202 on piston assembly 2. Therefore, when oil at the same pressure is input into either the first sealing cavity 201 or the second sealing cavity 202, the piston assembly 2 experiences the same force during extension and retraction, resulting in the same extension speed and retraction speed of piston assembly 2, facilitating control of piston assembly 2.

[0059] Figure 5 This is a schematic diagram of a partial cross-section of a piston assembly provided in an embodiment of this disclosure. Figure 6 This is a schematic diagram of a piston assembly after partial cross-section, provided in an embodiment of this disclosure. Figure 5 and Figure 6 The piston assembly 2 also includes a connector 26, which is located outside the cylinder body 1 and is connected to the end of the piston 22 away from the piston rod 23. The connector 26 is provided with a connection hole, through which the connector 26 is used to connect to deep-sea equipment so as to drive the movement of the deep-sea equipment.

[0060] Combination Figure 1 and Figure 2 Optionally, the pressure control component 3 includes a flexible container 31 filled with oil. The flexible container 31 can deform under water pressure and can drive the oil inside to the third sealing cavity 203 after deformation.

[0061] In the above implementation, since the flexible container 31 is filled with oil, when it is placed in seawater, the water pressure of the seawater will compress the flexible container 31, causing it to deform and drive the oil out of the container and into the third sealed cavity 203. That is, the pressure exerted on the oil in the flexible container 31 is the seawater pressure. After the flexible container 31 is connected to the third sealed cavity 203, the oil pressure within the third sealed cavity 203 becomes the seawater pressure. This allows for simple control of the oil pressure within the third sealed cavity 203 to be equal to the seawater pressure.

[0062] Optionally, the flexible container 31 has an annular structure and is fitted over the cylinder 1.

[0063] In the above implementation, the flexible container 31 has a ring structure, which increases the contact area between the flexible container and seawater, thereby enabling the flexible container to deform rapidly under seawater pressure and transfer the oil to the third sealing cavity 203.

[0064] In his example, the flexible container 31 can also be other structures, such as circular, elliptical, etc.

[0065] In this embodiment, the flexible container 31 is either a capsule or a bladder. This allows the oil entering the third sealed cavity 203 to be at the same pressure as the seawater pressure, even under seawater pressure.

[0066] See also Figure 2 Optionally, the outer cylinder liner 11 includes a cylinder head 111, a cylinder barrel 112, and a cylinder bottom 113. The cylinder head 111 is located outside the first end of the cylinder barrel 112 and is sealed around the outer sleeve 21, with the cylinder head 111 and cylinder barrel 112 in a sealed connection. The cylinder bottom 113 is located outside the second end of the cylinder barrel 112 and is sealed to both the inner center sleeve 12 and the cylinder barrel 112.

[0067] In the above implementation, setting the outer cylinder liner 11 to the above structure makes the outer cylinder liner 11 a detachable structure, which facilitates the assembly of piston assembly 2, etc.

[0068] In this embodiment, the cylinder head 111 has an annular structure and includes an insertion section 1111 and a limiting flange 1112. The limiting flange 1112 is connected to the outer wall of the insertion section 1111. When the cylinder head 111 is connected to the cylinder barrel 112, the insertion section 1111 is located between the outer cylinder body 211 and the cylinder barrel 112. One side of the limiting flange 1112 abuts against the end face of the cylinder barrel 112. The limiting flange 1112 and the cylinder barrel 112 are fastened together by multiple bolts or the like. A first oil port 101 is provided on the outer wall of the cylinder barrel 112 near the cylinder head 111. The first oil port 101 is located on the side of the limiting flange 1112 facing the cylinder bottom 113. The first oil port 101 communicates with the first sealing cavity 201.

[0069] To improve the sealing performance of the first sealing cavity 201, the inner wall of the insertion section 1111 is provided with multiple sealing grooves arranged at intervals along the axis of the cylinder 112, and a sealing ring is installed in each of the multiple sealing grooves. The outer wall of the insertion section 1111 is also provided with sealing grooves, and sealing rings are also installed in the sealing grooves.

[0070] The cylinder bottom 113 is also an annular structure, comprising a connecting section 1131 and a positioning protrusion 1132, the positioning protrusion 1132 being connected to the outer wall of the connecting section 1131. When the cylinder bottom 113 is connected to the cylinder barrel 112, the connecting section 1131 is located inside the cylinder barrel 112. One side of the positioning protrusion 1132 abuts against the other end face of the cylinder barrel 112. The positioning protrusion 1132 and the cylinder barrel 112 are fastened together by multiple bolts, etc.

[0071] To improve the sealing performance of the third sealing cavity 203, a sealing groove is provided on the outer wall of the connecting section 1131, and a sealing ring is also installed in the sealing groove.

[0072] A second oil port 102 is provided on the end face of the connecting section 1131, and the second oil port 102 communicates with the second sealing cavity 202. A third oil port 103 is provided on the outer wall of the cylinder barrel 112 near the positioning protrusion ring 1132, and the third oil port 103 is located on the side of the positioning protrusion ring 1132 facing the cylinder head 111. The third oil port 103 communicates with the third sealing cavity 203. In this way, high-pressure oil can be introduced into the first sealing cavity 201 through the first oil port 101, and high-pressure oil can also be introduced into the second sealing cavity 202 through the second oil port 102. At the same time, the oil can flow between the flexible container 31 and the third sealing cavity 203 through the third oil port 103.

[0073] In this embodiment, both the cylinder head 111 and the cylinder bottom 113 are annular plate structures. For ease of machining, the cylinder bottom 113 and the inner central sleeve 12 are integral structural components.

[0074] In addition, to facilitate connection between the cylinder bottom 113 and other structures, the cylinder block 1 also includes two connecting arms 14. The two connecting arms 14 are located outside the outer cylinder liner 11 and arranged opposite each other. One end of each connecting arm 14 is connected to the side of the cylinder bottom 113 away from the cylinder head 111, and the other end of the connecting arm 14 is arranged away from the piston rod 23. A connecting hole is provided at the other end of each connecting arm 14. A protective cover 4 is located between the two connecting arms 14.

[0075] The working process of the hydraulic cylinder provided in the embodiments of this disclosure is briefly described below:

[0076] In operation, the first sealing chamber 201 and the second sealing chamber 202 of the hydraulic cylinder are respectively connected to the two working ports of the directional valve. By controlling the position of the valve core of the directional valve, the hydraulic cylinder can extend and retract.

[0077] Figure 7 This is a schematic diagram of the structure of a hydraulic cylinder connected to a directional valve according to an embodiment of this disclosure, combined with... Figure 7When the directional valve 100 is in the neutral position, both the second working port b and the first working port a of the directional valve 100 are connected to the return port t. At this time, both the first sealing chamber 201 and the second sealing chamber 202 of the hydraulic cylinder are connected back to the oil tank, and there is no oil pressure in either the first sealing chamber 201 or the second sealing chamber 202. Furthermore, because the oil in the flexible container 31 is transmitted to the third sealing chamber 203 of the hydraulic cylinder under the action of water pressure, the oil pressure in the third sealing chamber 203 is the same as the external water pressure. Also, because the area of ​​the third annular surface 2031 is equal to the area of ​​the extended section of the piston 22, the piston 22 is in force balance and will not move.

[0078] When the directional valve 100 is energized in the left position, the oil inlet p of the directional valve 100 is connected to the second working oil port b, and the first working oil port a is connected to the return oil port t. At this time, oil enters the second oil port 102 of the hydraulic cylinder and exits the first oil port 101, and the inlet and outlet oil flow rates are the same. Under the action of water pressure, the oil in the flexible container 31 flows through the third oil port 103 to the third sealing chamber 203 of the hydraulic cylinder, which is balanced with the external water pressure on the piston rod 23. The piston rod 23 will only be subjected to the pressure of the oil source, pushing the piston rod 23 to extend.

[0079] When the directional valve 100 is energized in the right position, the oil inlet p of the directional valve 100 is connected to the first working oil port a, and the second working oil port b is connected to the return oil port t. At this time, oil enters through the first oil port 101 of the hydraulic cylinder and exits through the second oil port 102, with the inlet and outlet oil flow rates being the same. The oil in the third sealing chamber 203 of the hydraulic cylinder flows to the flexible container 31. The external water pressure on the piston rod 23 remains balanced, and the piston rod 23 is only subjected to the pressure of the oil source, pushing the piston rod 23 to extend.

[0080] The hydraulic cylinder provided in this embodiment has a third annular surface 2031 with an area S4 equal to the area of ​​the extended piston rod cross-section. Since the oil pressure in the third sealing cavity 203 is the same as the water pressure, the external water pressure on the piston rod during movement remains balanced with the oil pressure in the third sealing cavity 203, and is not affected by water depth. Simultaneously, the first annular surface 2011 and the second annular surface 2021 of the hydraulic cylinder have equal areas, ensuring that the oil flow rate is the same when the hydraulic cylinder extends and retracts, thus improving the output power and control precision of the hydraulic cylinder.

[0081] The hydraulic cylinder disclosed herein has a simple structure, is easy to maintain, and can safely and reliably achieve servo control of the actuator cylinder. It is particularly suitable for some small boats or special working conditions without magnetism or electricity.

[0082] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A hydraulic cylinder, characterized in that, The hydraulic cylinder includes a cylinder body (1), a piston assembly (2), and a pressure control assembly (3); The piston assembly (2) is movably located in the cylinder (1). The piston assembly (2) and the cylinder (1) define a first sealing cavity (201), a second sealing cavity (202), and a third sealing cavity (203). When the pressure in the first sealing cavity (201) is greater than the pressure in the second sealing cavity (202), the piston assembly (2) moves toward the interior of the cylinder (1). When the pressure in the first sealing cavity (201) is less than the pressure in the second sealing cavity (202), the piston assembly (2) extends out of the cylinder (1). The pressure control component (3) is located outside the cylinder (1) and connected to the cylinder (1). The pressure control component (3) is connected to the third sealing cavity (203). The pressure control component (3) is configured to apply a force to the piston assembly (2) through the third sealing cavity (203) when the piston assembly (2) extends or retracts. The force is the reaction force of the water pressure that the piston assembly (2) receives during extension or retraction.

2. The hydraulic cylinder according to claim 1, characterized in that, The cylinder body (1) includes an outer cylinder sleeve (11) and an inner center sleeve (12). The inner center sleeve (12) is located inside the outer cylinder sleeve (11), and the first end of the inner center sleeve (12) is connected to the first end of the outer cylinder sleeve (11). An annular space (120) is formed between the inner center sleeve (12) and the outer cylinder sleeve (11). The piston assembly (2) includes an outer sleeve (21) and a piston (22). The outer sleeve (21) is coaxially sleeved outside the piston (22), and the first end of the outer sleeve (21) is sealed to the piston (22). The second end of the outer sleeve (21) is movably located in the annulus (120) and is sealed to the inner wall of the outer cylinder liner (11) and the outer wall of the inner center sleeve (12), respectively. The first sealing cavity (201) is defined between the second end of the outer sleeve (21), the outer wall of the outer sleeve (21), and the inner wall of the outer cylinder sleeve (11); the second sealing cavity (202) is defined between the inner wall of the outer sleeve (21), the piston (22), and the inner wall of the inner center sleeve (12); and the third sealing cavity (203) is defined between the second end of the outer sleeve (21), the inner wall of the outer cylinder sleeve (11), and the outer wall of the inner center sleeve (12).

3. The hydraulic cylinder according to claim 2, characterized in that, The end face area of ​​the second end of the outer sleeve (21) is equal to the sum of the end face area of ​​the first end of the outer sleeve (21) and the end face area of ​​the first end of the piston (22).

4. The hydraulic cylinder according to claim 2, characterized in that, The outer sleeve (21) includes an outer cylinder (211) and a sealing ring platform (212). The sealing ring platform (212) is fitted over the first end of the outer cylinder (211) and is connected to the outer cylinder (211). The first end of the outer cylinder (211) is movably located in the annulus (120), and the second end of the outer cylinder (211) is located outside the cylinder (1).

5. The hydraulic cylinder according to claim 4, characterized in that, The piston assembly (2) further includes a piston rod (23), the first end of which is connected to the piston (22), the piston rod (23) is coaxially located in the outer cylinder (211), and the second end of which is movably located in the inner central sleeve (12). The piston rod (23) has an internal mounting space (230) for mounting a displacement sensor.

6. The hydraulic cylinder according to claim 5, characterized in that, The difference between the cross-sectional area of ​​the piston (22) and the cross-sectional area of ​​the piston rod (23) is equal to the end face area of ​​the sealing ring platform (212).

7. The hydraulic cylinder according to claim 5, characterized in that, The hydraulic cylinder also includes a protective cover (4), which is located outside the outer cylinder sleeve (11) and connected to one end of the outer cylinder sleeve (11). A sealed space (40) is formed between the protective cover (4) and the end face of the outer cylinder sleeve (11). The sealed space (40) is connected to the installation space (230), and the displacement sensor is located in the sealed space (40) and the installation space (230).

8. The hydraulic cylinder according to any one of claims 1-7, characterized in that, The pressure control component (3) includes a flexible container (31) filled with oil. The flexible container (31) can deform under water pressure and drive the oil inside into the third sealing cavity (203) after deformation.

9. The hydraulic cylinder according to claim 8, characterized in that, The flexible container (31) has a ring structure and is fitted over the cylinder (1).

10. The hydraulic cylinder according to claim 2, characterized in that, The outer cylinder liner (11) includes a cylinder head (111), a cylinder barrel (112), and a cylinder bottom (113). The cylinder head (111) is connected to the first end of the cylinder (112) and is fitted over the outer sleeve (21); The cylinder bottom (113) is connected to the second end of the cylinder barrel (112) and to the inner center sleeve (12).

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