Hydraulic apparatus

Abstract

The present application discloses a hydraulic apparatus. The hydraulic apparatus comprises: a cylinder body; a piston, the piston being arranged in the cylinder body and having an annular gap with the cylinder body, and the piston being sequentially provided with a plurality of sealing grooves that are circumferentially arranged at intervals along an axial direction from bottom to top; a plurality of sealing rings, each of the sealing grooves being respectively provided with the sealing ring, and the sealing ring being movably connected in the sealing groove; and at least one pressure adjusting structure, the pressure adjusting structure being capable of driving the sealing ring to move in the sealing groove, so as to adjust a gap between the sealing ring and the cylinder body. The present application discloses a hydraulic apparatus to solve the problem of severe sealing wear of an existing piston.

Description

Hydraulic device Technical Field

[0001] The present application relates to the field of hydraulic drive technology, and more specifically, to a hydraulic device. Background Art

[0002] A liquid hydrogen pump consists of a hydraulic end (i.e., a cold end) and a drive end. The cold end is placed inside a liquid hydrogen storage tank and immersed in liquid hydrogen; the drive end is placed outside the liquid hydrogen storage tank. The piston at the cold end is placed in a hydraulic device, and the piston and piston rod move together within the hydraulic device. The other end of the piston rod is connected to the working machine. There is a gap between the piston and the inner wall of the hydraulic device. Multiple sealing rings are installed in the gap to seal it and prevent excessive liquid hydrogen from slipping through the gap to the other side of the piston. This is also one of the measures to ensure the high volumetric efficiency of the liquid hydrogen pump.

[0003] In a multi-stage seal, the first seal (the seal ring at the bottom of the piston) is often subjected to the greatest force and therefore wears out the fastest. Often, the first seal is severely worn while the other seals are still nearly intact. This presents a serious problem: if seal wear becomes excessive before failure, the liquid hydrogen pump must be maintained and new seals replaced. This maintenance effort carries significant costs.

[0004] Therefore, a hydraulic device is needed to solve the above problems.

[0005] Summary of the Invention

[0006] In view of this, the purpose of this application is to propose a hydraulic device to solve the problem of severe wear of the existing piston seal.

[0007] Based on the above objectives, the present application provides a hydraulic device, comprising:

[0008] Cylinder body;

[0009] A piston is disposed in the cylinder body with an annular gap between the piston and the cylinder body; the piston is provided with a plurality of sealing grooves arranged in an axial direction and arranged in a circumferential direction in sequence from bottom to top;

[0010] A plurality of sealing rings, each of the sealing grooves is provided with a sealing ring, and the sealing ring is movably connected in the sealing groove;

[0011] At least one pressure regulating structure is provided, wherein the pressure regulating structure is capable of driving the sealing ring to move in the sealing groove to adjust the gap between the sealing ring and the cylinder body.

[0012] Optionally, when there is one pressure regulating structure, the pressure regulating structure is used to drive the sealing ring in the sealing groove at the bottom of the piston to move;

[0013] When there are multiple pressure regulating structures, each pressure regulating structure is respectively arranged corresponding to the sealing ring below the uppermost sealing groove of the piston, and is used in turn to drive the sealing ring of the piston to move in the sealing groove from bottom to top.

[0014] Optionally, when there are multiple pressure regulating structures, the regulating forces provided by the multiple pressure regulating structures are in an equal and increasing state from bottom to top along the piston.

[0015] Optionally, a surface of the sealing groove facing the lowermost side of the piston is set to be a rough surface.

[0016] Optionally, the rough surface is a plurality of protrusions arranged at equal intervals along the radial direction.

[0017] Optionally, the protrusion is an inverted boss or a frustum.

[0018] Optionally, an energizer is provided in the sealing groove, the energizer is placed in the sealing groove and in contact with the sealing ring; a first notch is provided on the energizer, and a second notch is provided on the sealing ring, and the first notch and the second notch are arranged opposite to each other along the axial direction of the piston.

[0019] Optionally, a positioning rod is provided on the energizer, and a positioning hole is extended from the sealing groove to cooperate with the positioning rod, and the positioning rod can move in the positioning hole; when the positioning rod contacts the sealing ring, it is used to limit the position of the second notch of the sealing ring and make the second notches of adjacent sealing rings staggered.

[0020] Optionally, at least two notches are provided on an edge of the energizer, and the at least two notches are symmetrically arranged on opposite sides of the positioning rod.

[0021] Optionally, at least one vortex groove is provided on at least a partial circumferential edge of the piston, and when there are multiple vortex grooves, the multiple vortex grooves are spaced apart along the axial direction of the piston; and / or at least one vortex groove is provided on the surface of the side of the sealing groove opposite to the rough surface; when there are multiple vortex grooves, the multiple vortex grooves are spaced apart along the axial direction of the piston.

[0022] Optionally, the pressure regulating structure includes a first regulating channel, a first valve core and a first driving member, the first regulating channel is arranged on the piston, the first regulating channel includes a first inlet end and at least one first outlet end, the first inlet end and the first outlet end are respectively connected to the cylinder body and the sealing groove, the first valve core is arranged in the first regulating channel, and the first driving member can drive the first valve core to open and close the first regulating channel.

[0023] In addition, optionally, the pressure regulating structure includes a second regulating channel, a second valve core and a second driving member, the second regulating channel is arranged on the piston, the second regulating channel includes a second inlet end and at least one second outlet end, the second inlet end is connected to the cylinder body, and the second outlet end is connected to the gap between the two adjacent sealing grooves; the second valve core is arranged in the second regulating channel, and the second driving member can drive the second valve core to open and close the second regulating channel.

[0024] As can be seen from the above, the hydraulic device provided by the present application has the following advantages compared with the prior art: using the above hydraulic device, according to the change of pressure in the cylinder, the gap between the sealing ring in the sealing groove of the piston and the inner wall of the cylinder is adjusted by the pressure regulating structure to provide sealing, lubrication, and pressure equalization respectively. The sealing ring of the piston realizes the sealing function; after the pressure of the previous seal of the piston (such as the first seal) reaches the specified pressure value, the pressure regulating structure switches from open to closed, and the pressure provided by the pressure regulating structure acts on the sealing ring. The gap between the sealing ring and the inner wall of the cylinder will cause some liquid hydrogen to leak to the next seal (such as the second seal). However, the leaked liquid hydrogen cannot push the previous sealing ring to move and completely fail the seal. Therefore, the seal still works, but is not enough to seal it completely. When liquid hydrogen acts on the piston, each sealing ring only seals a part of the pressure, and then the multiple sealing rings seal a part of the pressure step by step, realizing step-by-step pressure reduction. Finally, the multiple sealing rings add up to seal the entire liquid hydrogen pressure. While achieving sealing, the backward slip of liquid hydrogen is minimized, and the uniform sealing pressure makes the multiple sealing rings wear the same. The leaked liquid hydrogen forms good self-lubrication on the surface of the sealing ring, which greatly reduces the wear of the sealing ring, extends its service life, extends the maintenance cycle, and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above features and technical advantages of the present application will become clearer and easier to understand through the following description of its embodiments in conjunction with the accompanying drawings.

[0026] FIG1 is a partial cross-sectional view of a hydraulic device used in the first embodiment of the present application.

[0027] 2 to 5 are schematic diagrams of the rough surface of the sealing groove of the hydraulic device used in the embodiments of the present application.

[0028] FIG6 is a schematic diagram of an energizer of a hydraulic device used in an embodiment of the present application.

[0029] FIG7 is a schematic diagram of another energizer of the hydraulic device used in an embodiment of the present application.

[0030] FIG8 is a partial cross-sectional view of the hydraulic device used in the second embodiment of the present application.

[0031] FIG9 is a partial cross-sectional view of the hydraulic device used in the third embodiment of the present application.

[0032] FIG10 is a partial cross-sectional view of the hydraulic device used in the fourth embodiment of the present application.

[0033] FIG11 is a schematic diagram showing the correlation between pressure and time during use of the hydraulic device used in an embodiment of the present application.

[0034] The figure marks are as follows: 10-inner wall; 11-sealing surface; 20-piston; 201-second gap; 21-rough surface; 22-adjusting channel; 23-first spring; 24-ball; 25-second spring; 26-locking nut; 27-pressure-inducing hole; 28-annular gap; 281-first gap; 29-vortex groove; 30-sealing ring; 40-energizer; 41-positioning rod; 42-notch; 50-high-pressure liquid hydrogen; 60-valve core; 61-third spring; 70-guide ring mounting groove. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of this application more clearly understood, the present application is further described below in conjunction with specific embodiments and with reference to the accompanying drawings. Identical parts are denoted by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings. The terms "inward" and "outward" refer to directions toward or away from the geometric center of a particular component, respectively.

[0036] The application scenario of the hydraulic device is a high-pressure liquid hydrogen pump. Liquid hydrogen is stored in a liquid hydrogen storage tank. The temperature of the liquid hydrogen storage tank is ultra-low temperature (20K). At ultra-low temperatures, steel becomes brittle and its strength weakens. There is also a risk of hydrogen corrosion in hydrogen working conditions. Therefore, under current technology, the maximum pressure resistance of liquid hydrogen storage tanks is relatively low. The hydrogen refueling station for liquid hydrogen storage requires high-pressure gaseous hydrogen to refuel vehicles loaded with compressed hydrogen. Therefore, a high-pressure liquid hydrogen pump is needed to compress the liquid hydrogen to high pressure, and then vaporize it into high-pressure gaseous hydrogen for use by the hydrogen refueling machine.

[0037] Figure 1 is a partial cross-sectional view of a hydraulic device used in the first embodiment of the present application. As shown in Figure 1, the hydraulic device includes a cylinder, a piston 20, a plurality of sealing rings 30 and at least one pressure regulating structure.

[0038] The cylinder body includes but is not limited to a hydraulic cylinder, and the cylinder body has an accommodating cavity.

[0039] The piston 20 is arranged in the cylinder body and has an annular gap between it and the cylinder body; a plurality of sealing grooves are arranged in sequence from bottom to top in the axial direction and arranged in a circumferential ring; the piston 20 is movably arranged in the accommodating cavity, and there is a circumferential gap between the circumferential edge of the piston 20 and the inner wall 10 of the cylinder body.

[0040] Each sealing groove is fitted with a sealing ring 30, which is movably connected within the groove. The sealing ring 30 and the sealing groove cooperate to provide a seal for the piston 20. The piston 20 is provided with multiple seals spaced from bottom to top. The seal below the piston 20 is the front seal, while the seal above the piston 20 is the back seal. The sealing ring 30 can move left and right and up and down within the sealing groove. The closer the sealing ring 30 is to the sealing groove, the larger the gap between the sealing ring 30 and the cylinder body. The further the sealing ring 30 is from the sealing groove, the smaller the gap between the sealing ring 30 and the cylinder body.

[0041] The pressure regulating structure can drive the sealing ring 30 to move within the sealing groove to adjust the gap between the sealing ring 30 and the cylinder body. When the pressure regulating structure is open (i.e., high-pressure liquid hydrogen 50 can pass through), it can drive the sealing ring 30 to move within the sealing groove, such as approaching the sealing groove or the inner wall 10 of the cylinder body, to increase or decrease the gap between the piston 20 and the cylinder body. When the pressure regulating structure is closed, it can drive the sealing ring 30 to remain stationary within the sealing groove.

[0042] The sealing groove and the sealing ring 30 cooperate with each other to provide a sealing effect for the cylinder body. When the piston 20 moves back and forth along the accommodating chamber of the cylinder body, the pressure on the piston 20 gradually changes, and the position of the sealing ring 30 also changes accordingly, thereby providing lubrication and pressure equalization. When the pressure begins to increase, the pressure regulating structure opens, and the pressure regulating structure drives the sealing ring 30 to move toward the side away from the sealing groove, such as pushing the sealing ring 30 from right to left, providing a sealing effect. At this time, the gap between the sealing ring 30 and the inner wall 10 of the cylinder body is the smallest. As the high-pressure liquid hydrogen 50 enters the gap between the cylinder body and the piston 20, both sides of the sealing ring 30 are driven by a driving force, wherein the first side is the pressure regulating structure pushing the sealing ring 30 close to the cylinder body, wherein the second side is the gap between the piston 20 and the inner wall 10 of the cylinder body connected to the sealing groove, and the high-pressure liquid hydrogen 50 pushes the sealing ring 30 away from the cylinder body after entering the gap, such as pushing the sealing ring 30 from left to right. Under the driving force from both sides, the gap between the sealing ring 30 and the inner wall 10 of the cylinder body increases slightly, allowing high-pressure liquid hydrogen 50 to pass through this gap and provide lubrication for this seal. When the pressure continues to increase and reaches a predetermined value, the pressure regulating structure switches from open to closed. The pressure provided by the pressure regulating structure acts on the sealing ring 30, keeping it stationary in the sealing groove. The gap between the sealing ring 30 and the inner wall 10 of the cylinder body remains unchanged, allowing the high-pressure liquid hydrogen 50 to pass through this gap and enter the next seal, thereby achieving pressure equalization.

[0043] The above hydraulic device is used to adjust the gap between the sealing ring 30 in the sealing groove of the piston 20 and the inner wall 10 of the cylinder body according to the change in the pressure in the cylinder body through the pressure regulating structure to provide sealing, lubrication, and pressure equalization respectively. The sealing ring 30 of the piston 20 realizes the sealing function; after the pressure of the previous seal of the piston 20 (such as the first seal) reaches the specified pressure value, the pressure regulating structure switches from open to closed, and the pressure provided by the pressure regulating structure acts on the sealing ring 30. The gap between the sealing ring 30 and the inner wall 10 of the cylinder body will cause some high-pressure liquid hydrogen 50 to leak to the next seal (such as the second seal). However, the leaked high-pressure liquid hydrogen 50 cannot push the previous sealing ring 30 to move and cause the seal to fail completely. Therefore, the seal still works, but is not enough to seal it completely. When liquid hydrogen acts on the piston 20, each sealing ring 30 only seals a part of the pressure, and then the multiple sealing rings 30 seal a part of the pressure step by step, achieving a step-by-step pressure reduction. Finally, the multiple sealing rings 30 add up to seal the entire liquid hydrogen pressure. While achieving sealing, the backward slippage of liquid hydrogen is minimized, and the uniform sealing pressure ensures uniform wear on multiple sealing rings 30. The leaked liquid hydrogen forms a good self-lubricating effect on the surface of the sealing ring 30, which greatly reduces the wear of the sealing ring 30, extends its service life, lengthens maintenance cycles, and reduces costs.

[0044] In one embodiment of the present application, the surface of the sealing ring 30 facing the inner wall 10 of the cylinder body is a sealing surface 11, and an annular gap 28 is formed between the piston 20 and the inner wall 10 of the cylinder body. The gap is formed between the sealing surface 11 and the inner wall 10 of the cylinder body, and the gap between the sealing surface 11 and the inner wall 10 of the cylinder body changes continuously with the movement of the sealing ring 30.

[0045] Typically, the seal at the bottom of the piston 20 wears out first. To extend the service life of the piston 20, optionally, when there is a single pressure-regulating structure, the pressure-regulating structure is used to drive the movement of the sealing ring 30 in the bottommost sealing groove of the piston 20. When there are multiple pressure-regulating structures, each pressure-regulating structure is provided corresponding to the sealing ring 30 below the topmost sealing groove of the piston 20 and is used to sequentially drive the movement of the sealing rings 30 in the sealing grooves of the piston 20 from bottom to top. If the piston 20 is provided with ten seals, the tenth seal is used to provide sealing, and the remaining nine or fewer seals can be equipped with pressure-regulating structures. That is, pressure-regulating structures can be provided for the nine or fewer seals from bottom to top. For example, if there are five seals, then five pressure-regulating structures can be provided from bottom to top, so that all ten or fewer seals experience the same degree of wear. When the pressure regulating mechanism is open, high-pressure liquid hydrogen 50 can pass through the sealing ring 30 of the piston 20, achieving a seal or pressure equalization effect. When the pressure regulating mechanism switches from open to closed, some high-pressure liquid hydrogen 50 will leak along the sealing surface 11 of the first (or each) sealing ring 30 toward the next seal. However, the leaked high-pressure liquid hydrogen 50 cannot push the sealing ring 30 of that seal to completely fail. Therefore, the seal still works, but is insufficient to completely seal. The leaked liquid hydrogen forms a good self-lubricant on the sealing surface 11, which greatly reduces the wear of the sealing ring 30 of that seal.

[0046] Optionally, when there are multiple pressure regulating structures, the regulating forces provided by the multiple pressure regulating structures increase in equal values ​​from bottom to top along the piston 20. Multiple seals are provided on the piston 20 from bottom to top, each seal comprising a sealing groove and a sealing ring 30. Except for the last seal at the top, the sealing groove of each seal is connected to a pressure regulating structure. Each seal can only seal a certain amount of pressure to achieve pressure equalization, thereby achieving the same pressure drop across each sealing ring 30 and ultimately achieving the same wear, further extending the service life, extending the maintenance cycle, and reducing costs.

[0047] In one embodiment of the present application, piston 20 is provided with ten seals, sequentially from bottom to top. The sealing grooves of the first through ninth seals are all connected to a pressure regulating structure, which includes, but is not limited to, a pressure relief valve. The spring force within the pressure relief valve sets the relief pressures of 5MPa, 10MPa, 15MPa, 20MPa, 25MPa, 30MPa, 35MPa, 40MPa, and 45MPa, respectively, for the first through ninth seals. That is, when the pressure of high-pressure liquid hydrogen 50 reaches 5MPa, the pressure regulating structure of the first seal closes; the high-pressure liquid hydrogen 50 continues to move toward the second seal. When the pressure of high-pressure liquid hydrogen 50 reaches 10MPa, the pressure regulating structure of the second seal closes; the high-pressure liquid hydrogen 50 continues to move toward the next seal.

[0048] The sealing groove includes an upper surface, a lower surface, and an inner surface. The upper surface is the side surface facing the bottom of the piston 20, and the lower surface is the side surface facing the top of the piston 20. The upper and lower surfaces are arranged relative to each other, and the sealing ring 30 can move back and forth between the upper and lower surfaces. The inner surface is arranged relative to the inner wall 10 of the cylinder body, and the sealing ring 30 can move back and forth between the inner surface and the inner wall 10 of the cylinder body. To better position the sealing ring 30, the side surface of the sealing groove facing the bottom of the piston 20 (i.e., the upper surface or upper pressure-bearing surface) is optionally provided with a rough surface 21. The sealing ring 30 cannot move when in contact with the rough surface 21 and has a positioning function. It can move freely after being separated from the rough surface 21.

[0049] The upper pressure-bearing surface of the multiple sealing grooves on the piston 20 (i.e., the surface on one side facing the bottom surface of the piston 20) is roughened. When the sealing ring 30 is pressed against the rough surface 21, the static friction force is very large, so that the sealing ring 30 cannot move left or right. When the piston 20 moves downward, the pressure of the high-pressure liquid hydrogen is transmitted to the sealing ring 30, pushing the sealing ring 30 upward, forming a large static friction force, which prevents the sealing ring 30 from moving. In particular, when the pressure regulating structure is closed, the static friction force and the force provided by the pressure regulating structure together ensure that the position of the sealing ring 30 remains unchanged. The inability to move laterally ensures that the sealing pressure between the sealing ring 30 and the inner wall 10 remains unchanged. When the piston 20 moves upward, the sealing ring 30 is separated from the rough surface 21 and can move freely.

[0050] Figures 2 through 5 are schematic diagrams of the roughened surface of the sealing groove of the hydraulic device used in the embodiments of the present application. Figures 2 through 5 illustrate different structural forms of the roughened surface. The roughened surface 21 strongly hinders the movement of the sealing ring 30 away from the cylinder body, but has relatively little effect on the movement of the sealing ring 30 toward the cylinder body.

[0051] Optionally, the rough surface 21 is a plurality of protrusions arranged at equal intervals along the radial direction. The protrusions are evenly distributed on the sealing groove to provide uniform friction. In addition, the protrusions can be arranged at unequal intervals according to specific requirements.

[0052] There are many ways to implement the rough surface 21. As shown in Figure 2, a plurality of triangular protrusions are provided on the surface of the bottom side of the sealing groove facing the piston 20. The right side of the triangular protrusion is a slope, forming a structure similar to a barb, so that the protrusion has a strong obstruction effect on the movement of the sealing ring 30 to the right, and has little obstruction effect on the movement of the sealing ring 30 to the left.

[0053] As shown in FIG3 , a plurality of symmetrical triangular protrusions are provided on the surface of the sealing groove on the lowermost side facing the piston 20, forming a structure similar to a cross barb, so that the protrusions have a strong hindering effect on the movement of the sealing ring 30 to the right, and a small hindering effect on the movement of the sealing ring 30 to the left.

[0054] As shown in FIG4 , a plurality of stack-shaped protrusions are provided on the lowermost side surface of the sealing groove toward the piston 20. The stack-shaped protrusions can play a positioning role for the sealing ring 30 in contact with it, preventing the sealing ring 30 from relative displacement.

[0055] Optionally, the protrusion is an inverted boss or cone. The boss or cone includes a connecting surface and a contact surface disposed opposite each other. The connecting surface is used to connect to the sealing groove, and the contact surface is used to contact the sealing ring. The diameter of the connecting surface is larger than the diameter of the contact surface, and the diameter of the boss or cone is gradually changing, that is, the closer to the connecting surface, the larger the diameter, and the closer to the connecting surface, the smaller the diameter. The connecting surface of the cone or boss has a certain contact area, which can provide the required friction for the sealing ring.

[0056] As shown in FIG5 , a plurality of bosses or cones are provided on the lowermost surface of the sealing groove facing the piston 20 . The trapezoidal bosses can position the sealing ring 30 in contact therewith to prevent relative displacement of the sealing ring 30 .

[0057] In one embodiment of the present application, the height of the rough surface 21, that is, the height of the protrusions, is in the range of 0.01-1 mm, and the multiple protrusions are evenly distributed on the contact surface with a distribution density of 1-100 / cm 2 Alternatively, the protrusions are arranged in rows and protrude in a ridge-like manner from the sealing groove of the piston 20 to position the sealing ring 30.

[0058] To better expand the sealing ring 30, an energizer 40 is optionally provided within the sealing groove. The energizer 40 is positioned within the sealing groove and in contact with the sealing ring 30. The energizer 40 is provided with a first notch (not shown), and the sealing ring 30 is provided with a second notch (not shown). The first and second notches are positioned opposite each other along the axial direction of the piston 20. By positioning the first and second notches, the sealing performance of the sealing ring 30 can be improved. The energizer 40 applies a force to one side surface of the sealing ring 30, pushing the sealing ring 30 to move. This reduces the difficulty of actuation and facilitates a timely response from the sealing ring 30.

[0059] In one embodiment of the present application, the energizer 40 is C-shaped, i.e., it is provided with a first notch, forming a non-closed loop. For example, the driving force provided by the pressure regulating structure acts on the energizer 40 and the sealing ring 30, causing the sealing ring 30 to generate a leftward thrust, thereby generating a sealing pressure on the inner wall 10 of the cylinder. This sealing pressure is equivalent to or slightly higher than the set pressure of the corresponding pressure regulating structure, thereby achieving a pressure equalization function.

[0060] After accommodating the sealing ring 30, the sealing groove needs to be installed with the energizer 40. A certain distance is maintained between the energizer 40 and the sealing groove to facilitate the application of high-pressure liquid hydrogen 50 to the energizer 40. By appropriately reducing the volume of the space behind the energizer 40 (i.e., the second gap 201), the pressure of the fluid leaking from the pressure regulating structure is transmitted more quickly, thereby applying pressure to the sealing ring 30.

[0061] Fig. 6 is a schematic diagram of an energizer of the hydraulic device used in the embodiment of the present application. As shown in Fig. 6 , a positioning rod 41 is provided on the energizer 40 .

[0062] To further stabilize the position of the energizer 40, a positioning rod 41 is optionally provided on the energizer 40. A positioning hole extends from the sealing groove to cooperate with the positioning rod 41, and the positioning rod 41 is movable within the positioning hole. When the positioning rod 41 contacts the sealing ring 30, it defines the position of the second notch of the sealing ring 30 and staggers the second notches of adjacent sealing rings 30. The positioning hole communicates with the sealing groove, or the positioning hole communicates with both the sealing groove and the pressure regulating structure. The energizer 40 comprises an inner surface and an outer surface. The positioning rod 41 is disposed on the outer surface, located in the middle or upper middle portion of the energizer 40 and extending away from the energizer 40. It is typically a round rod. The positioning rod 41 and the first notch are disposed on opposite sides of the energizer 40. The positioning rod 41 moves within the positioning hole to define the position and range of movement of the energizer 40 and the sealing ring 30 within the sealing groove. Furthermore, the limited range of movement of the energizer 40 allows the energizer 40 to respond more effectively and quickly to pressure relief.

[0063] Furthermore, when the sealing ring 30 is C-shaped, i.e., provided with a second notch, forming a non-closed loop, after the energizer 40 is positioned by the positioning rod 41, the notch in the energizer 40 can be used to reposition the sealing ring 30, thereby staggering the gaps in the sealing ring 30 and achieving optimal sealing performance. Multiple adjustment channels 22 and positioning holes can be provided, each communicating with a positioning hole. These multiple connected adjustment channels 22 and positioning holes are then evenly distributed around the circumference of the piston 20, effectively positioning the openings of the sealing ring 30 and preventing the openings of the sealing ring 30 from converging at the same angle during operation, causing large, uncontrolled leakage.

[0064] Fig. 7 is a schematic diagram of another energizer of the hydraulic device used in the embodiment of the present application. As shown in Fig. 7 , a notch 42 is provided on the energizer 40 .

[0065] To enhance the energizing effect of the energizer 40, at least two notches 42 are optionally provided on the edge of the energizer 40. The at least two notches 42 are symmetrically arranged on opposite sides of the positioning rod 41. One or more notches 42 are provided on either side near the positioning rod 41. The notches 42 can be semicircular, or other shapes are also possible. This makes the strength of these areas slightly weaker than other areas, allowing them to expand the sealing ring 30 outward with greater roundness during deformation, thereby enhancing the energizing effect.

[0066] To reduce the effect of the fluid between the piston 20 and the inner wall 10 on the sealing ring 30 and the energizer 40, the sealing ring 30 can be widened or the sealing groove narrowed, and the first gap 281 between the sealing ring 30 and the sealing groove can be appropriately reduced. This limits the amount and speed of high-pressure liquid hydrogen 50 leaking through the annular gap 28 and flowing through the gap to the second gap 201 on the side of the energizer 40. Optionally, at least one vortex groove 29 is provided on at least a portion of the circumferential edge of the piston 20; if there are multiple vortex grooves 29, the multiple vortex grooves 29 are spaced apart along the axial direction of the piston 20, and / or at least one vortex groove 29 is provided on the surface of the sealing groove opposite the rough surface 21; if there are multiple vortex grooves 29, the multiple vortex grooves 29 are spaced apart along the axial direction of the piston 20. The vortex groove 29 is a groove-shaped structure extending along the direction of fluid flow. When the fluid flows through the vortex groove 29, it will be diverted to form backflow and vortex. The backflow is opposite to the direction of the original fluid, which hinders the flow of the original fluid and slows down the flow rate, thereby hindering the source flow, thereby reducing the speed and pressure of this part of the fluid acting on the sealing ring 30 and the energizer 40.

[0067] Referring to FIG. 1 , optionally, the pressure regulating structure includes a first regulating channel 22, a first valve core, and a first driving member. The first regulating channel 22 is disposed on the piston 20. The first regulating channel 22 includes a first inlet end and at least one first outlet end, the first inlet end and the first outlet end being in communication with the cylinder body and the sealing groove, respectively. The first valve core is disposed within the first regulating channel 22. The first driving member is connected to the first valve core, and the first driving member is capable of driving the first valve core to open and close the first regulating channel 22. When the pressure does not reach a predetermined value, the first regulating channel 22 remains open. When high-pressure liquid hydrogen 50 enters the first regulating channel 22, the pressure gradually increases, and the first driving member begins to drive the first valve core to operate. When the pressure reaches the predetermined value, the first driving member and the first valve core close the first regulating channel 22. When the pressure again falls below the predetermined value, the first driving member begins to drive the first valve core to operate again.

[0068] In one embodiment of the present application, the pressure regulating structure includes, but is not limited to, a pressure relief valve. The first regulating channel 22 utilizes a variable diameter pressure relief hole, and the first valve core utilizes a ball 24. The ball 24 moves within a certain range. When the ball 24 moves to the minimum diameter point, the first regulating channel 22 is closed, and when the ball 24 leaves the minimum diameter point, the first regulating channel 22 is opened. The first driving member utilizes two springs, namely, a first spring 23 and a second spring 25. The first spring 23 is longer than the second spring 25. The first spring 23 and the second spring 25 are respectively arranged on opposite sides of the ball 24. The other end of the first spring 23 is arranged at the top of the first regulating channel 22. The bottom end of the first regulating channel 22 passes through the piston 20 and is internally provided with a locking nut 26. A pressure-inducing through hole 27 is provided in the center of the locking nut 26. The opposite ends of the pressure-inducing through hole 27 respectively connect the first regulating channel 22 and the cylinder body. The other end of the second spring 25 is arranged on the locking nut 26. When the pressure does not reach the predetermined value, the first regulating channel 22 remains open. When high-pressure liquid hydrogen 50 enters the first regulating channel 22, as the pressure gradually increases, the first spring 23 compresses and the second spring 25 stretches, causing the ball 24 to move. When the pressure reaches the predetermined value, the ball 24 moves to the point of minimum diameter, and the first regulating channel 22 switches from open to closed. When the pressure again falls below the predetermined value, the first spring 23 and the second spring 25 reset, driving the ball 24 away from the point of minimum diameter, and the first regulating channel 22 switches from closed to open.

[0069] Multiple pressure relief valves are provided. By controlling the elastic force of the first spring 23 and the second spring 25, the set closing pressure of the pressure relief valve can be selected. For example, the closing pressures of the nine pressure relief valves from the bottom to the top of the piston 20 can be set to 5MPa, 10MPa, 15MPa, 20MPa, 25MPa, 30MPa, 35MPa, 40MPa, and 45MPa, respectively. The pressure of the high-pressure liquid hydrogen 50 transmitted to the back of each sealing ring 30 is gradually increased, resulting in a uniform increase in pressure on the sealing surface 11 of each seal, and an equal pressure differential between the seals, thereby achieving a controlled and step-by-step sealing of the high-pressure liquid hydrogen 50.

[0070] Figure 8 is a partial cross-sectional view of the hydraulic device used in the second embodiment of the present application. The main difference between Figure 8 and Figure 1 lies in the different structures of the valve core and driver, as well as the inclusion of a guide ring mounting groove 70. The first valve core utilizes a T-shaped valve core 60, and the first driver utilizes a third spring 61. The third spring 61 is sleeved onto the valve core 60, allowing the valve core 60 to approach the lock nut 26 and abut against the first channel's reducing section. When the pressure does not reach a predetermined value, the third spring 61 pushes the valve core 60 toward the lock nut 26, keeping the first regulating channel 22 open. When high-pressure liquid hydrogen 50 enters the first regulating channel 22, the pressure gradually increases, pushing the valve core 60 upward and beginning to compress the third spring 61. When the pressure reaches a predetermined value, the third spring 61 further compresses, causing the valve core 60 to move to its minimum diameter, switching the first regulating channel 22 from open to closed. When the pressure again falls below the predetermined value, the third spring 61 resets, driving the valve core 60 away from its minimum diameter, switching the first regulating channel 22 from closed to open. The guide ring mounting groove 70 is provided on the piston 20 for mounting the guide ring. The guide ring ensures the accuracy of the movement of the piston 20 and avoids excessive deviation that affects the sealing performance of the piston 20.

[0071] In addition to the above-mentioned implementation methods, the pressure regulating structure can also be implemented in another way. Figure 9 is a partial cross-sectional view of the hydraulic device used in the third embodiment of the present application. As shown in Figure 9, the pressure regulating structure includes a second regulating channel 22, a second valve core, and a second driving member.

[0072] The difference in structure between the second adjustment channel 22 shown in Figure 9 and the first adjustment channel 22 shown in Figure 1 is that the first adjustment channel 22 is directly connected to the sealing groove, and the second adjustment channel 22 is connected to the annular gap 28 between the piston 20 and the inner wall 10 of the cylinder body, and then connected to the sealing groove through the annular gap 28.

[0073] Optionally, the pressure regulation structure includes a second regulating channel 22, a second valve core, and a second driver. The second regulating channel 22 is disposed on the piston 20 and includes a second inlet and at least one second outlet. The second inlet communicates with the cylinder body, and the second outlet communicates with the gap between two adjacent sealing grooves. The second valve core is disposed within the second regulating channel 22, and the second driver is capable of driving the second valve core to open and close the second regulating channel 22. The second outlet of the second regulating channel 22 of the pressure regulation structure is disposed between the two adjacent sealing grooves, that is, within the annular gap 28 between the two sealing rings 30. When the pressure does not reach a predetermined value, the second regulating channel 22 remains open. When high-pressure liquid hydrogen 50 enters the second regulating channel 22, the pressure gradually increases, and the second driver begins to drive the second valve core. When the pressure reaches the predetermined value, the second driver's second valve core closes the second regulating channel 22. When the pressure again falls below the predetermined value, the second driver begins to drive the second valve core again.

[0074] A pressure relief fluid at a predetermined pressure directly relieves the pressure in the annular gap 28 between two adjacent sealing rings 30, causing the pressure in the annular gap 28 between each sealing ring 30 to reach the set pressure. The pressure differential between the upper and lower sides of each sealing ring 30 is then a set pressure differential. During movement of the piston 20, the pressure distribution between the two adjacent sealing rings 30 is based on the set value, balancing the pressure of the fluid flowing through the annular gap 28 between the piston 20 and the inner wall 10. The residual pressure after balancing is the final sealing pressure. The residual pressure is the smaller value after the lower pressure offsets the upper pressure. For example, the pressure differential for each seal can be set to 5 MPa.

[0075] FIG10 is a partial cross-sectional view of the hydraulic device used in the fourth embodiment of the present application. As shown in FIG10 , the main difference between FIG10 and FIG9 is that the piston 20 is provided with an eddy current groove 29 .

[0076] To better achieve the desired sealing pressure, in this way, the flow rate of the fluid flowing from the gap between the piston 20 and the inner wall 10 of the cylinder (i.e., the first gap 28) can also be limited, so that the pressure relief pressure takes effect first. Optionally, a plurality of vortex grooves 29 spaced apart along the axial direction are provided on the circumferential edge of the piston 20, and / or a plurality of vortex grooves 29 spaced apart along the radial direction are provided on the surface of the bottom side of the sealing groove facing away from the piston 20. The vortex grooves 29 limit the flow rate of the fluid flowing from the first gap 28, so that the fluid from the pressure relief channel takes effect first, that is, the pressure relief pressure takes effect first. The pressure relief pressure will push the sealing ring 30 downward and to the left first. After the pressure of the high-pressure liquid hydrogen flowing from the first gap 28 on the lower side is transmitted to the sealing ring 30, it offsets the pressure on the upper side, and then the sealing ring 30 is positioned and sealed according to the residual pressure. The sealing pressure at this time is the pressure difference between the upper and lower fluids. Once positioned, the sealing ring 30 cannot move any further and can only work under the sealing pressure at the time of positioning, thereby achieving the desired sealing pressure.

[0077] The following further introduces the use of the hydraulic device.

[0078] Figure 11 is a schematic diagram showing the correlation between pressure and time during use of the hydraulic device used in the embodiment of the present application, wherein: P1 is the equalizing pressure; t1 is the equalizing time; P2 is the positioning pressure; t2 is the positioning time; P3 is the sealing pressure; and t3 is the sealing time.

[0079] As shown in FIG11 , the piston 20 in the liquid hydrogen compression stroke can be summarized as “pressure equalization first, positioning second, and sealing third”.

[0080] There are ten seals on the piston 20. The sealing grooves and the sealing rings 30 cooperate with each other to provide a seal for the cylinder body. When the piston 20 moves back and forth along the accommodating chamber of the cylinder body, the pressure on the piston 20 gradually changes, and the position of the sealing ring 30 also changes accordingly, thereby providing lubrication and pressure equalization. From bottom to top, the first nine sealing grooves all have a pressure regulating structure, namely a pressure relief valve. The spring elastic force in the pressure relief valve corresponding to the first nine seals sets the pressure relief pressures of 5MPa, 10MPa, 15MPa, 20MPa, 25MPa, 30MPa, 35MPa, 40MPa, and 45MPa respectively.

[0081] During the liquid hydrogen compression stroke, the pressure regulating structure switches from open to closed. The liquid hydrogen pressure squeezes the ball 24 through the pressure relief hole, compressing the first spring 23 and stretching the second spring 25. When the set pressure is reached, the pressure relief valve closes. The set pressure then acts on the energizer 40 and the sealing ring 30, causing the sealing ring 30 to generate a leftward thrust, generating a sealing pressure that is equivalent to or slightly higher than the set pressure of the corresponding pressure relief valve, achieving a pressure equalization function.

[0082] During the compression stroke of liquid hydrogen, the high pressure of the high-pressure liquid hydrogen flowing from the annular gap 28 first acts on the sealing ring 30, causing the sealing ring 30 to generate upward pressure, forcing the sealing ring 30 to adhere tightly to the rough surface 21 of the sealing groove. The rough surface 21 provides a large static friction force, thereby preventing the sealing ring 30 from moving, thus achieving the positioning function.

[0083] During the liquid hydrogen compression stroke, the amount and speed of liquid flowing from annular gap 28 to first gap 281 and second gap 201 are limited due to the reduction in first gap 281 and the obstruction of vortex groove 29. Furthermore, due to the reduced volume of second gap 201, the pressure leaking from the pressure relief valve is transmitted more rapidly, and the leftward sealing thrust of sealing ring 30 is primarily driven by the pressure of high-pressure liquid hydrogen 50 leaking from the pressure relief valve. After the high-pressure liquid hydrogen 50 flowing from annular gap 28 flows into second gap 201, the high pressure within second gap 201 cannot push sealing ring 30 further toward the cylinder wall due to the positioning effect of rough surface 21. However, the high pressure within second gap 201 can offset the reaction force exerted on sealing ring 30 by the high-pressure liquid hydrogen 50 leaking from sealing surface 11, preventing sealing ring 30 from moving away from the cylinder wall and ensuring that the seal does not completely fail.

[0084] Because the sealing pressure on the previous sealing surface 11 is lower than the pressure of the high-pressure liquid hydrogen 50, some of the high-pressure liquid hydrogen 50 will leak out of the next seal (upward) along the sealing surface 11. However, the leaking high-pressure liquid hydrogen 50 cannot push the sealing ring 30 of this line to the right, causing the seal to completely fail. It can only leak upward through the gap in the sealing surface 11, so the seal still works, but it is not enough to seal it completely. The leaking high-pressure liquid hydrogen 50 forms a good self-lubricant on the sealing surface 11, which greatly reduces the wear of the sealing ring 30. Through the quantitative leakage of the above leakage process on the nine seals, good self-lubrication is achieved while making the wear of all the sealing rings 30 nearly the same.

[0085] The sealing ring 30 relies on the high-pressure liquid hydrogen 50 for self-lubrication and needs to be infiltrated by the high-pressure liquid hydrogen 50. At the same time, the slippage of the high-pressure liquid hydrogen 50 cannot be too large. The above-mentioned hydraulic device reduces the slippage of the high-pressure liquid hydrogen 50 to 1% by setting ten seals. The liquid hydrogen pump including the above-mentioned hydraulic device has a high volumetric efficiency.

[0086] From the above description and practice, it can be seen that the hydraulic device provided by the present application has the following advantages compared with the prior art: using the above hydraulic device, according to the change of pressure in the cylinder, the gap between the sealing ring 30 in the sealing groove of the piston and the inner wall of the cylinder is adjusted by the pressure regulating structure to provide sealing, lubrication and pressure equalization respectively. The sealing ring 30 of the piston realizes the sealing effect; after the pressure of the previous seal of the piston (such as the first seal) reaches the specified pressure value, the pressure regulating structure is switched from open to closed, and the pressure provided by the pressure regulating structure acts on the sealing ring 30. The gap between the sealing ring 30 and the inner wall of the cylinder will cause a part of the high-pressure liquid hydrogen 50 to leak to the next seal (such as the second seal), but the leaked high-pressure liquid hydrogen 50 cannot push the previous sealing ring 30 to move and make the seal completely ineffective, so the seal still works, but is not enough to seal it completely. When liquid hydrogen acts on the piston 20, each sealing ring 30 only seals a part of the pressure, and then the multiple sealing rings 30 seal a part of the pressure step by step, realizing step-by-step pressure reduction, and finally the multiple sealing rings 30 add up to seal the entire liquid hydrogen pressure. While achieving sealing, the backward slippage of liquid hydrogen is minimized, and the uniform sealing pressure ensures uniform wear on multiple sealing rings 30. The leaked liquid hydrogen forms a good self-lubricating effect on the surface of the sealing ring 30, which greatly reduces the wear of the sealing ring 30, extends its service life, lengthens maintenance cycles, and reduces costs.

[0087] Those skilled in the art should understand that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the scope of the present application should be included in the scope of protection of the present application.

Claims

1. A hydraulic device, characterized in that: include: Cylinder body; A piston, wherein the piston is disposed in the cylinder body and has an annular gap between the piston and the cylinder body; The piston is provided with a plurality of sealing grooves arranged in an axial direction in sequence from bottom to top and arranged in a circumferential direction; A plurality of sealing rings, each of the sealing grooves is provided with a sealing ring, and the sealing ring is movably connected in the sealing groove; At least one pressure regulating structure is provided, wherein the pressure regulating structure can drive the sealing ring to move in the sealing groove to adjust the gap between the sealing ring and the cylinder body.

2. The hydraulic device according to claim 1, characterized in that: When there is one pressure regulating structure, the pressure regulating structure is used to drive the sealing ring in the sealing groove at the bottom of the piston to move; When there are multiple pressure regulating structures, each of the pressure regulating structures is respectively arranged corresponding to the sealing ring below the uppermost sealing groove of the piston, and is used in turn to drive the sealing ring in the sealing groove of the piston to move from bottom to top.

3. The hydraulic device according to claim 2, characterized in that: When there are multiple pressure regulating structures, the regulating forces provided by the multiple pressure regulating structures are increased in equal values ​​from bottom to top along the piston.

4. The hydraulic device according to any one of claims 1 to 3, characterized in that: The surface of the sealing groove on one side facing the lowermost side of the piston is configured as a rough surface.

5. The hydraulic device according to claim 4, characterized in that: The rough surface is a plurality of protrusions arranged at equal intervals along the radial direction.

6. The hydraulic device according to claim 5, characterized in that: The protrusion is in the form of an inverted boss or a frustum.

7. The hydraulic device according to claim 4, characterized in that: An energizer is arranged in the sealing groove, the energizer is placed in the sealing groove and contacts the sealing ring; a first notch is arranged on the energizer, a second notch is arranged on the sealing ring, and the first notch and the second notch are arranged opposite to each other along the axial direction of the piston.

8. The hydraulic device according to claim 7, characterized in that: The energizer is provided with a positioning rod, and a positioning hole used in conjunction with the positioning rod is extended from the sealing groove, and the positioning rod can move in the positioning hole; when the positioning rod contacts the sealing ring, it is used to limit the position of the second notch of the sealing ring and make the second notches of adjacent sealing rings staggered.

9. The hydraulic device according to claim 8, characterized in that: The edge of the energizer is provided with at least two notches, and the at least two notches are symmetrically arranged on opposite sides of the positioning rod.

10. The hydraulic device according to claim 4, characterized in that: At least one vortex groove is arranged on at least a partial circumferential edge of the piston, and when there are multiple vortex grooves, the multiple vortex grooves are spaced apart along the axial direction of the piston; and / or at least one vortex groove is arranged on the surface of the side of the sealing groove opposite to the rough surface; when there are multiple vortex grooves, the multiple vortex grooves are spaced apart along the axial direction of the piston.

11. The hydraulic device according to any one of claims 1 to 3, characterized in that: The pressure regulating structure includes a first regulating channel, a first valve core and a first driving member. The first regulating channel is arranged on the piston. The first regulating channel includes a first inlet end and at least one first outlet end. The first inlet end and the first outlet end are respectively connected to the cylinder body and the sealing groove. The first valve core is arranged in the first regulating channel. The first driving member can drive the first valve core to open and close the first regulating channel.

12. The hydraulic device according to any one of claims 1 to 3, characterized in that: The pressure regulating structure includes a second regulating channel, a second valve core and a second driving member, the second regulating channel is arranged on the piston, the second regulating channel includes a second inlet end and at least one second outlet end, the second inlet end is connected to the cylinder body, and the second outlet end is connected to the gap between two adjacent sealing grooves; the second valve core is arranged in the second regulating channel, and the second driving member can drive the second valve core to open and close the second regulating channel.

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