Oil cylinder suitable for high-pressure environment

Abstract

The invention discloses an oil cylinder suitable for a deep sea high-pressure environment, and belongs to the technical field of deep sea equipment. The oil cylinder is designed aiming at the requirements of extremely high external pressure, corrosion and long service life in deep sea. An oil cylinder outer shell is high in pressure bearing capacity, and a supporting assembly composed of a plurality of supporting rings and a guide limiting assembly connected with the supporting assembly are arranged in the oil cylinder outer shell. The guiding and limiting assembly forms a continuous rigid guiding chain through sliding connection of a plurality of limiting pieces, multi-point accurate guiding with extremely high rigidity is provided for the piston rod under deep sea high pressure, and unbalance loading and deformation are effectively resisted. The front end supporting ring is provided with an anti-locking oil groove, and pressure impact caused by oil way cut-off is avoided. The oil cylinder end cover integrates multi-stage sealing and a lubricating groove communicated with an oil cavity, and it is ensured that sealing is reliable and lubricating is sufficient under the huge pressure difference. The sealing lubricating system is firm in structure and excellent in guiding precision and stability, is optimized for high pressure difference, and is particularly suitable for hydraulic executing mechanisms of equipment such as deep-sea exploration and operation robots.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic transmission and actuator, in particular to an oil cylinder with optimized structure design, which can maintain high stability and reliability under high pressure, high load and long stroke working conditions. BACKGROUND

[0002] As a core linear motion actuator, hydraulic cylinder has been widely used in the industry. However, with the development of ocean resource development, deep sea scientific research and underwater engineering construction, hydraulic actuators need to be directly applied to deep sea extreme environment. Deep sea environment (usually refers to water depth more than 1000 meters) has harsh characteristics such as ultra-high hydrostatic pressure (up to tens of megapascals), strong corrosion (seawater, chloride ions, microorganisms), low temperature, darkness and difficult maintenance, which poses unprecedented challenges to traditional oil cylinders.

[0003] At present, the oil cylinder suitable for land or ordinary industrial high pressure environment mainly has the following problems in deep sea application: Insufficient structure pressure resistance and deformation resistance: The design of the outer shell of the ordinary oil cylinder mainly considers the internal working pressure, which is difficult to resist the extremely high external hydrostatic pressure applied in deep sea, and is easy to cause compression deformation, instability and even damage of the cylinder body, resulting in change of internal volume, movement jam or seal failure.

[0004] Guiding system instability under high pressure: Under high pressure in deep sea, the radial load borne by the piston rod and the internal support structure increases significantly. The traditional single or short distance guiding sleeve structure is easy to lose precision due to pressure deformation, resulting in increased piston rod deflection and vibration, which not only affects the control precision of movement, but also accelerates the eccentric wear and failure of the seal.

[0005] Sealing and lubrication problem under high pressure difference: Deep sea oil cylinder faces the complex pressure difference relationship between high pressure in the cylinder and ultra-high hydrostatic pressure outside the cylinder. Under the alternating action of such huge bidirectional pressure difference, the conventional sealing structure is prone to leakage, extrusion or early wear. At the same time, if the lubrication system is not designed properly, it is difficult to effectively deliver lubricating oil to the key friction pair under high pressure difference, resulting in dry friction, high temperature rise and rapid reduction of seal life.

[0006] High corrosion resistance and reliability requirements: Deep sea water has strong corrosion, and the maintenance cycle is extremely long. The materials and surface treatment of ordinary oil cylinder are difficult to resist corrosion for a long time, and corrosion of key moving parts and sealing surface will directly lead to performance degradation and functional failure.

[0007] System pressure impact and reliability risk: In the closed hydraulic system in deep sea, if the internal oil way of the oil cylinder is completely closed due to improper piston position, it is easy to produce huge pressure impact (water hammer effect), which not only causes pipe vibration and noise, but also may damage valves, sensors, and even threaten the safety of the whole deep sea equipment.

[0008] Poor adaptability and maintainability: for different deep-sea operation depths (pressure) and travel requirements, traditional oil cylinders often need to be completely redesigned, and the degree of generalization and modularization is low. At the same time, within the limited deployment and recovery window of deep-sea equipment, the oil cylinder is required to have good maintainability, and the traditional structure is often inconvenient to disassemble.

[0009] Therefore, it has become an urgent and key technical requirement in the field of deep-sea equipment technology to develop a special oil cylinder that can stably withstand deep-sea super-high external pressure for a long time, has extremely high guiding accuracy and rigidity, is equipped with a reliable sealing and lubricating system under super-high pressure difference, and has good corrosion resistance and environmental adaptability. The present application arises in this background. SUMMARY

[0010] The present application aims to overcome the above-mentioned defects of the prior art and provides an oil cylinder adapted to high-pressure environment. The main purpose is: Provide an internal structure with multiple levels, continuous and rigid guiding function, which significantly improves the straightness accuracy and anti-unbalanced load capacity of the piston rod in high-pressure long-stroke movement.

[0011] Optimize the sealing and lubrication design of the end cover area to ensure reliable sealing and small friction and wear under high pressure.

[0012] Effectively prevent the oil passage from being accidentally completely blocked when the piston moves near the oil port, and ensure stable system pressure.

[0013] Through the modular and expandable guiding and limiting component design, the same basic structure can flexibly adapt to the requirements of different cylinder body lengths, improving the universality and economy of the product.

[0014] To achieve the above-mentioned purposes, the present application adopts the following technical solutions: An oil cylinder adapted to high-pressure environment, comprising an oil cylinder outer shell, both ends of which are provided with openings and are closed by oil cylinder end covers. The outer shell is provided with an oil inlet and an oil outlet. A slidable oil cylinder piston is arranged in the outer shell, and the piston is connected to a piston rod. A support assembly is symmetrically arranged on both sides of the piston, and each support assembly comprises a plurality of rear end support rings arranged in the axial direction and at least one front end support ring close to the oil port. The front end support ring is circumferentially provided with an anti-lock oil groove, and the center of all support rings is provided with a straight line guide hole matched with the piston rod.

[0015] The support assembly is connected with a guide limiting assembly. The guide limiting assembly includes two end limiting members and a plurality of middle limiting members. The two end limiting members are respectively fixedly connected with the oil cylinder piston and the oil cylinder shell body (or a structure fixed with the shell body). The number of the middle limiting members is equal to the sum of the number of the rear end support ring and the front end support ring, or equal to an integer multiple of the sum. Each of the middle limiting members is fixedly connected with a corresponding support ring (when the number is the sum) or a group of support rings (when the number is a multiple of the sum) through a fixed connecting block.

[0016] The end limiting member and each of the middle limiting members have opposite two ends, one end of which is provided with a straight guide slot, and the other end is provided with a sliding guide connecting head matched with the straight guide slot. When assembled, the guide slot of the end limiting member connected with the piston is slidably sleeved with the connecting head of the adjacent first middle limiting member; the guide slot at the other end of the middle limiting member is slidably sleeved with the connecting head of the next middle limiting member, and so on, to form a continuous guide chain composed of all the limiting members connected in sequence. This structure strictly limits the support ring to be able to only translate in the axial direction, and cannot rotate or radially displace, thereby constructing an internal guide frame with high strength and high precision for the piston rod.

[0017] Further, a sliding connection through hole is formed in the oil cylinder end cover for the piston rod to pass through, and a wiper ring, a sealing ring and a guide ring are sequentially embedded in the through hole from the outside to the inside. A lubricating groove is also processed on the inner wall of the sliding connection through hole. One embodiment of the lubricating groove is composed of a plurality of coaxial annular grooves connected by axial communication grooves, and at least one communication groove is communicated with the inner cavity of the cylinder body. Another embodiment of the lubricating groove is a continuous multi-turn (more than two turns) spiral groove, one end of which is communicated with the inner cavity of the cylinder body. Both of the two kinds of lubricating grooves can guide the pressure oil in the oil chamber to the sealing ring and guide ring area to achieve forced lubrication.

[0018] Further, a starting groove (such as an internal hexagonal hole) is formed in the outer end face of the oil cylinder end cover, facilitating installation and disassembly.

[0019] Further, the oil cylinder can be designed as a piston rod unidirectional extension (unidirectional oil cylinder) or bidirectional extension (bidirectional oil cylinder) as needed.

[0020] Compared with the prior art, the oil cylinder provided by the present application has the following advantages: The oil cylinder shell body and the overall structure are optimized for deep-sea ultra-high hydrostatic pressure, and combined with the support of the internal rigid guide chain, can effectively resist the deformation of the cylinder body caused by external pressure, and ensure the safe and stable operation of the structure at a depth of thousands of meters.

[0021] The innovative "support ring group + guide limiting chain" composite guide system rigidly connects multiple discrete support rings into a whole guide frame through the sliding connection of the limiting piece, and realizes the accurate radial constraint of the piston rod for a long distance, continuously, multiple points and without gap. This fundamentally solves the problem of bending and shaking of the piston rod under high pressure, has high straightness and strong resistance to lateral load.

[0022] The integrated optimized sealing combination and active pressure oil lubrication channel (annular groove or spiral groove) at the end cover ensure that a stable lubricating oil film can be formed in the sealing area at the highest working pressure. This greatly reduces the friction coefficient and wear rate, eliminates dry friction caused by sealing burning, greatly prolongs the service life of the sealing system, and reduces internal leakage.

[0023] The anti-lock oil groove design on the front end support ring skillfully avoids the "water hammer effect" or flow cutoff when the piston moves to the oil port position, so that the oil pressure changes gently, the system impact is small, the operation is stable, and the control accuracy and reliability of the overall equipment are improved.

[0024] The core improvement lies in the number relationship design of the guide limiting assembly. By setting the number of middle limiting pieces to be the total number of support rings or an integer multiple, the axial spacing between the support ring groups can be flexibly adjusted. For example, when the oil cylinder needs to be lengthened, the number of middle limiting pieces and the corresponding spacing support ring groups can be increased in proportion, so that different stroke lengths can be adapted while maintaining the same guiding accuracy and rigidity level, realizing the modularization and serialization design of the core guiding structure, and reducing the research and production cost.

[0025] The start groove and other designs on the end cover make disassembly and maintenance more convenient.

[0026] In summary, the present application provides an oil cylinder solution with excellent performance, long service life and flexible design under high pressure and harsh working conditions, which has high industrial application value. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a schematic diagram of the sectional structure of an embodiment of the present application.

[0028] Figure 2 It is a schematic diagram of the sectional structure of an embodiment of the present application.

[0029] Figure 3 It is a schematic diagram of the sectional structure of an embodiment of the present application.

[0030] Figure 4 It is a sectional view of an embodiment of the end cover of the oil cylinder.

[0031] BRIEF DESCRIPTION OF DRAWINGS: 1. Hydraulic cylinder housing; 2. Cylinder end cap; 21. Sliding connection through hole; 22. Lubrication groove; 23. Starting groove; 24. Sweeper ring; 25. Sealing ring; 26. Guide ring; 3. Oil port; 4. Hydraulic cylinder piston; 5. Piston rod; 6. Support components; 61. Rear end support ring; 62. Front end support ring; 63. Anti-lock oil groove; 64. Straight guide hole; 7. Guide and limiting assembly; 71. End limiting component; 72. Middle limiting component; 73. Fixed connecting block; 74. Linear guide groove. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Example 1

[0033] like Figures 1 to 4 As shown, this embodiment provides a bidirectional hydraulic cylinder adapted to high-pressure environments. The cylinder housing 1 is made of high-strength alloy steel tubing with threads at both ends. Two identical cylinder end caps 2 are threaded together and fastened to both ends of the housing 1. Each end cap 2 has a precision sliding connection through hole 21 machined in its center. A polyurethane wiper ring 24, a fluororubber combination sealing ring 25, and a wear-resistant plastic guide ring 26 are sequentially installed inside the through hole 21. The inner wall of the through hole 21 is machined with... Figure 4 The spiral lubrication groove 22 shown (about 3-4 turns) has its starting end connected to the inner cavity of the cylinder through a radial hole.

[0034] Two oil ports 3 are symmetrically opened in the middle of the housing 1. The cylinder piston 4 divides the inner cavity of the housing into two working chambers. The piston 4 is fixed to the piston rod 5 by threads, and the two ends of the piston rod 5 pass through the end caps 2 at both ends.

[0035] On each side of the piston 4, a set of support components 6 is installed. Each set of components includes three rear support rings 61 made of brass and one front support ring 62 of the same material, arranged in sequence. The straight guide hole 64 at the center of all support rings (61, 62) is precisely clearance-fitted with the piston rod 5. The outer circumference of the front support ring 62 is milled with four evenly distributed axial anti-lock oil grooves 63.

[0036] The guide limiting assembly 7 is the core of this embodiment. Each side uses one end limiting piece 71 fixed with the piston 4, one end limiting piece 71 fixed with the inner side of the housing end, and four middle limiting pieces 72 (the number is equal to the total number of support rings on this side: 3 rear ends + 1 front end = 4). Each middle limiting piece 72 is bolted with a corresponding support ring through a steel fixing connecting block 73. All limiting pieces (71, 72) are made of high-hardness steel, one end of which is a straight guide groove 74 with a T-shaped cross-section, and the other end is a T-shaped sliding guide connector (the protruding part in the figure). When installing, start with the end limiting piece 71 on the piston side, its guide groove is inserted with the connector of the first middle limiting piece 72, and the guide groove at the other end of the middle limiting piece 72 is connected with the second middle limiting piece 72, and so on for all four middle limiting pieces 72, and finally connected with the end limiting piece 71 on the housing side, forming a rigid sliding guide chain. This chain restricts all support rings to move strictly synchronously in the axial direction, providing the piston rod 5 with extremely stable guidance.

[0037] The outer end face of the end cover 2 is machined with an internal hexagonal starting groove 23, which facilitates tightening with a wrench. Embodiment 2

[0038] The main difference between this embodiment and embodiment 1 is that the stroke of the oil cylinder is longer to accommodate a larger working range. To maintain the same level of guidance accuracy and rigidity, in the support assembly 6, six rear-end support rings 61 and two front-end support rings 62 are used on each side (a total of 8 support rings). Correspondingly, the number of middle limiting pieces 72 in the guide limiting assembly 7 is 1 times the total number of support rings (8), i.e. 8. Each middle limiting piece 72 is still connected to one support ring one-to-one. By increasing the number of support rings and limiting pieces and distributing them evenly, it is ensured that within the lengthened cylinder, the piston rod 5 can obtain dense and continuous support and guidance throughout the long stroke. Embodiment 3

[0039] This embodiment shows another adaptation method. The stroke of the oil cylinder is between that of embodiments 1 and 2. The support assembly 6 on each side uses four rear-end support rings 61 and one front-end support ring 62 (a total of 5 support rings). In order to simplify assembly and adjust the average spacing between support rings, the number of middle limiting pieces 72 in the guide limiting assembly 7 is 2 times the total number of support rings (5), i.e. 10. At this time, every two middle limiting pieces 72 form a group, connected to a support ring through a longer fixing connecting block 73. This "multiple" relationship allows the designer to adjust the distribution density of the support ring group in the axial direction and the segment length of the overall guide chain by changing the number of middle limiting pieces and the connection method, while keeping the total number of support rings unchanged, thereby more finely optimizing the guide rigidity distribution inside oil cylinders of different lengths to achieve optimal performance.

[0040] The working principle of the present application is briefly described as follows: High pressure oil enters from one side oil port 3, pushing the piston 4 and the piston rod 5 to move to the other side. The piston rod 5 is supported radially by all the linear guide holes 64 in the two side support assemblies 6. At the same time, the entire support assembly 6 is strictly constrained by the rigid sliding chain formed by the guide and limiting assembly 7, and can only translate as a whole in the axial direction. This "rod-hole matching" plus "chain rigid guide" double mechanism ensures the ultra-high standard straightness of the movement. The end cover lubrication groove 22 introduces high pressure oil into the sealing area to form an oil film. The anti-locking oil groove 63 ensures smooth oil passage. Thus, smooth, accurate and reliable operation under high pressure is achieved.

[0041] Regarding the working principle and force analysis of the guide and limiting assembly 7: each middle limiting piece 72 is rigidly integrated with the corresponding support ring through the fixed connecting block 73, rather than simply being guided or passing through. When the piston rod 5 is subjected to radial eccentric load under deep-sea high pressure, the load is first transmitted to the middle limiting piece rigidly connected thereto through the support ring in contact therewith. Since all the limiting pieces are connected end to end through the high-precision linear sliding pair 74, and the two ends are fixed with the piston 4 and the cylinder body 1 respectively, the entire system forms an over-determined spatial truss structure. The local radial force is quickly decomposed and converted into multiple small axial forces and internal moments distributed along the guide chain, forcing the support ring with a tendency to deviate to "align" with its adjacent support ring. The structure relies on its own geometric constraints and stiffness to dynamically correct and suppress the radial displacement of the piston rod, thereby achieving the overall self-centering function of the "rigid guide chain" and effectively preventing radial interference and instability during reciprocating motion.

[0042] The mating surfaces of the sliding pair can adopt a large contact area cross section as shown in the attached Figure 3 schematic drawing (or explicitly described as T-shaped, dovetail-shaped), which not only ensures smooth axial sliding, but also provides strong resistance to radial separation and torsion through mechanical interlocking, ensuring the structural integrity of the guide chain under high pressure.

[0043] It should be noted that the above examples are only used to illustrate the design idea and preferred embodiment of the present application, and are not a limitation on the scope of protection. For those skilled in the art, without departing from the principles of the present application, some changes, substitutions and modifications to the lubrication groove shape, support ring material, limiting piece specific structure, connection method, etc. should be included within the scope of protection of the claims of the present application.

Claims

1. An oil cylinder adapted to a high-pressure environment, comprising: an oil cylinder outer shell (1) having two ends with openings; an oil cylinder end cover (2) connected to the two end openings of the oil cylinder outer shell (1) respectively; an oil port (3) provided on the oil cylinder outer shell (1); an oil cylinder piston (4) slidingly installed in the oil cylinder outer shell (1); a piston rod (5) connected to the oil cylinder piston (4); characterized in that it further comprises: a support assembly (6) provided on both sides of the oil cylinder piston (4), comprising at least one front end support ring (62) and a plurality of rear end support rings (61), the front end support ring (62) being provided with an anti-locking oil groove (63), and the rear end support ring (61) and the front end support ring (62) being both provided with a straight line guide hole (64) in the center; a guide and limiting assembly (7) comprising two end limiting members (71) and a plurality of middle limiting members (72), the end limiting members (71) being fixedly connected to the oil cylinder piston (4) and the oil cylinder outer shell (1) respectively, and the middle limiting members (72) being fixedly connected to the support rings one by one; wherein the end limiting members (71) and the middle limiting members (72) are slidingly connected through a straight line guide groove (74) and a sliding guide connector to form a continuous guide structure.

2. The oil cylinder according to claim 1, characterized in that The oil cylinder end cover (2) is provided with a sliding connection through hole (21), and the through hole is sequentially provided with a water scraping ring (24), a sealing ring (25) and a guide ring (26).

3. The oil cylinder of claim 2, wherein, The sliding connection through hole (21) is further provided with a lubricating groove (22) on the inner wall, the lubricating groove (22) is a circular annular lubricating groove, comprising a plurality of interconnected lubricating circular grooves, and being communicated with the oil chamber of the oil cylinder through the groove.

4. The oil cylinder of claim 2, wherein, The sliding connection through hole (21) is further provided with a lubricating groove (22) on the inner wall, the lubricating groove (22) is a spiral lubricating groove, the number of spiral turns is greater than two, and one end is communicated with the oil chamber of the oil cylinder.

5. The oil cylinder of claim 1, wherein The anti-locking oil groove (63) is provided on the front end support ring (62) to prevent the oil port (3) from being blocked when oil is fed or discharged.

6. The oil cylinder of claim 1, wherein The oil cylinder is a one-way oil cylinder or a two-way oil cylinder.

7. The oil cylinder of claim 1, wherein The number of middle limiting members (72) is equal to the sum of the number of rear end support rings (61) and front end support rings (62), or the number of middle limiting members (72) is equal to a multiple of the sum of the number of rear end support rings (61) and front end support rings (62).

8. The oil cylinder of claim 1, wherein, The straight line guide groove (74) and the sliding guide connector are respectively provided at both ends of the limiting member to form a guide chain connected in sequence.

9. The oil cylinder of claim 2, wherein, The outer end surface of the oil cylinder end cover (2) is provided with a starting groove (23) for rotating and tightening or disassembling the oil cylinder end cover (2).

10. The oil cylinder of claim 1, wherein, In the support assembly (6), the front end support ring (62) and the rear end support ring (61) are connected through a fixed connecting block (73), and the anti-locking oil grooves (63) are uniformly distributed along the circumference of the front end support ring (62).

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