Hydraulic device

Abstract

The present application discloses a hydraulic device, which includes: a cylinder body; a piston, which is arranged in the cylinder body and has an annular gap between the piston and the cylinder body; a plurality of sealing grooves arranged in an axial direction and arranged circumferentially in sequence from bottom to top on the piston; a plurality of sealing rings, each of which is provided with a sealing ring, which can be movably connected in the sealing groove; and at least one pressure regulating structure, which can drive the sealing ring to move in the sealing groove to adjust the gap between the sealing ring and the cylinder body. The present application discloses a hydraulic device to solve the problem of serious wear of the existing piston seal.

Description

Technical Field

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

[0002] The liquid hydrogen pump includes a hydraulic end (i.e., a cold end) and a driving end. The cold end is placed in a liquid hydrogen storage tank and immersed in liquid hydrogen; the driving end is placed outside the liquid hydrogen storage tank. The piston of the cold end is placed in a hydraulic device. The piston moves together with the piston rod in 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 set in the gap for sealing to prevent excessive liquid hydrogen from sliding 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 multiple seals, the first seal (i.e. the seal ring at the bottom of the piston) is often subjected to the greatest force, so the first seal wears the fastest. Often, the first seal ring is severely worn, while the other seal rings are almost intact. This brings a serious problem. If the seal wears too much and fails, the liquid hydrogen pump must be maintained and a new seal ring must be replaced. And the maintenance is accompanied by huge cost expenditures.

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

[0005] In view of this, the purpose of the present application is to provide a hydraulic device to solve the problem of severe wear of the existing piston seal.

[0006] Based on the above purpose, the present application provides a hydraulic device, comprising:

[0007] Cylinder body;

[0008] A piston, the piston is arranged 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 and arranged in a circumferential direction in sequence from bottom to top;

[0009] 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;

[0010] 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.

[0011] 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;

[0012] 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.

[0013] 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.

[0014] Optionally, a surface of the sealing groove on a side facing the lowermost side of the piston is arranged to be a rough surface.

[0015] Optionally, the rough surface is a plurality of protrusions arranged at equal intervals along the radial direction.

[0016] Optionally, the protrusion is an inverted boss or a frustum.

[0017] 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, 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.

[0018] Optionally, a positioning rod is provided on the energizer, and a positioning hole used in conjunction with the positioning rod extends 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.

[0019] Optionally, at least two notches are provided on the edge of the energizer, and at least two of the notches are symmetrically arranged on opposite sides of the positioning rod.

[0020] Optionally, at least one vortex groove is provided on at least a partial circumferential edge of the piston, and when the number of the vortex grooves is multiple, 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 the number of the vortex grooves is multiple, the multiple vortex grooves are spaced apart along the axial direction of the piston.

[0021] 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.

[0022] 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 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.

[0023] As can be seen from the above, the hydraulic device provided by the present application has the following advantages compared with the prior art: the above hydraulic device is used to adjust the gap between the sealing ring in the sealing groove of the piston and the inner wall of the cylinder body through the pressure regulating structure according to the change of the pressure in the cylinder body, so as to provide sealing, lubrication and pressure equalization respectively. The sealing ring of the piston realizes the sealing effect; after the pressure of the previous seal (such as the first seal) of the piston 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, and the gap between the sealing ring and the inner wall of the cylinder body will have a part of the liquid hydrogen leaking to the next seal (such as the second seal), but the leaked liquid hydrogen cannot push the previous seal ring to move and make the seal completely ineffective, so the seal still works, but it is not enough to seal all. 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, and finally the multiple sealing rings add up to seal all the liquid hydrogen pressure together. While achieving sealing, the backward slippage of liquid hydrogen is minimized, and the uniform sealing pressure makes the wear of multiple sealing rings 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, prolongs the maintenance cycle and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above-mentioned 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.

[0025] Figure 1 It is a partial cross-sectional view of the hydraulic device used in the first embodiment of the present application.

[0026] Figures 2 to 5 Schematic diagram of the rough surface of the sealing groove of the hydraulic device used in the embodiment of the present application.

[0027] Figure 6 Schematic diagram of an energizer of a hydraulic device used in an embodiment of the present application.

[0028] Figure 7 Schematic diagram of another energizer of the hydraulic device used in the embodiment of the present application.

[0029] Figure 8 This is a partial cross-sectional view of the hydraulic device used in the second embodiment of the present application.

[0030] Fig. 9 It is a partial cross-sectional view of the hydraulic device used in the third embodiment of the present application.

[0031] Fig.10 This is a partial cross-sectional view of the hydraulic device used in the fourth embodiment of the present application.

[0032] Fig.11 Schematic diagram of the correlation between pressure and time during use of the hydraulic device used in the embodiment of the present application.

[0033] The reference numerals are:

[0034] 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 through hole; 28-annular gap; 281-first gap; 29-eddy current 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] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. The same parts are represented by the same figure numerals. It should be noted that the words "front", "rear", "left", "right", "up" and "down" used in the following description refer to the directions in the accompanying drawings. The words "inside" and "outside" used refer to the direction toward or away from the geometric center of a specific 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. In addition, there is 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. Hydrogen refueling stations that store liquid hydrogen require 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 in the hydrogen refueling machine.

[0037] Figure 1 FIG. 1 is a partial cross-sectional view of the hydraulic device used in the first embodiment of the present application. Figure 1 As shown, the piston comprises 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 direction; 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] A sealing ring 30 is provided in each sealing groove, and the sealing ring 30 can be movably connected in the sealing groove; the sealing ring 30 and the sealing groove cooperate with each other to provide a seal for the piston 20, and the piston 20 is provided with multiple seals from bottom to top. The piston 20 is the front seal relative to the bottom, and the piston 20 is the back seal relative to the top. The sealing ring 30 can move left and right and up and down in 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, and the farther 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 in the sealing groove to adjust the gap between the sealing ring 30 and the cylinder body. When the pressure regulating structure is turned on (i.e., the high-pressure liquid hydrogen 50 can pass through), the sealing ring 30 can be driven to move in the sealing groove, such as close to the sealing groove or close to 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 turned off, the sealing ring 30 can be driven to remain stationary in 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 is turned on, 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, to provide 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 action of driving forces on both sides, the gap between the sealing ring 30 and the inner wall 10 of the cylinder body increases slightly, so that the high-pressure liquid hydrogen 50 can pass through the seal from the gap and provide lubrication for the seal. When the pressure continues to increase and reaches a predetermined 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, so that the sealing ring 30 remains stationary in the sealing groove, and the gap between the sealing ring 30 and the inner wall 10 of the cylinder body remains unchanged, so that the high-pressure liquid hydrogen 50 can pass through the seal from the gap and enter the next seal, thereby achieving a pressure equalization effect.

[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 through the pressure regulating structure according to the change of the pressure in the cylinder body, so as to provide sealing, lubrication and pressure equalization respectively. The sealing ring 30 of the piston 20 realizes the sealing effect; after the pressure of the previous seal (such as the first seal) of the piston 20 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, and the gap between the sealing ring 30 and the inner wall 10 of the cylinder body will have a part of the high-pressure liquid hydrogen 50 leaking 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 it 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 all the liquid hydrogen pressure together. While achieving sealing, the backward sliding amount of liquid hydrogen is minimized, and the uniform sealing pressure makes the wear of multiple sealing rings 30 the same. The leaked liquid hydrogen forms a good self-lubricating agent on the surface of the sealing ring 30, which greatly reduces the wear of the sealing ring 30, prolongs its service life, extends the maintenance cycle, 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, an annular gap 28 is formed between the piston 20 and the inner wall 10 of the cylinder body, a 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] Usually, the seal at the bottom of the piston 20 is the first to wear out. In order to extend the service life of the piston 20, optionally, when there is one pressure regulating structure, the pressure regulating structure is used to drive the seal ring 30 in the seal groove at the bottom of the piston 20 to move; when there are multiple pressure regulating structures, each pressure regulating structure is respectively set corresponding to the seal ring 30 under the seal groove at the top of the piston 20, and is used to drive the seal ring 30 in the seal groove from bottom to top of the piston 20 to move in sequence. If the piston 20 is provided with ten seals, the tenth seal is used to provide sealing, and the remaining nine or less than nine seals can be equipped with a pressure regulating structure, that is, a pressure regulating structure can be provided for the nine or less than nine seals from bottom to top, such as five seals, and five seals from bottom to top, so that the ten or less than ten seals are worn to the same extent. When the pressure regulating structure is turned on, the high-pressure liquid hydrogen 50 can pass through the sealing ring 30 of the piston 20 to achieve sealing or pressure equalization; when the pressure regulating structure is switched from on to off, a portion of the high-pressure liquid hydrogen 50 will leak along the sealing surface 11 of the first (or each) sealing ring 30 to the next seal, but the leaked high-pressure liquid hydrogen 50 cannot push the sealing ring 30 to move and make the seal completely ineffective, so the seal still works, but is not enough to seal it completely. The leaked liquid hydrogen forms good self-lubrication on the sealing surface 11, which greatly reduces the wear of the sealing ring 30.

[0046] Optionally, when there are multiple pressure regulating structures, the regulating forces provided by the multiple pressure regulating structures are in an equal value increasing state from bottom to top along the piston 20. Multiple seals are arranged on the piston 20 from bottom to top, each seal includes 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 balance the pressure, so that the pressure drop of each sealing ring 30 is the same, and finally the wear is the same, which further extends the service life, extends the maintenance cycle, and reduces the cost.

[0047] In one embodiment of the present application, ten seals are sequentially arranged on the piston 20 from bottom to top, and the sealing grooves of the first to ninth seals are all connected with a pressure regulating structure, which includes but is not limited to a pressure relief valve, and the pressure relief pressures set by the spring force in the pressure relief valve are 5MPa, 10MPa, 15MPa, 20MPa, 25MPa, 30MPa, 35MPa, 40MPa and 45MPa from the first to the ninth respectively. That is, when the pressure of the high-pressure liquid hydrogen 50 is 5Mpa, the pressure regulating structure of the first seal is closed; the high-pressure liquid hydrogen 50 continues to move to the second seal, and when the pressure of the high-pressure liquid hydrogen 50 is 10Mpa, the pressure regulating structure of the second seal is closed; the high-pressure liquid hydrogen 50 continues to move to 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 surface and the lower surface are arranged opposite to each other, and the sealing ring 30 can move back and forth between the upper surface and the lower surface. The inner surface is arranged opposite 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. In order to better position the sealing ring 30, optionally, the side surface of the sealing groove facing the bottom of the piston 20 (i.e., the upper surface or the upper pressure-bearing surface) is set as 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 leaving 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 close to 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, and the static friction force 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 jointly ensure that the position of the sealing ring 30 remains unchanged. The inability to move horizontally 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 to 5 FIG. 2 is a schematic diagram of a rough surface 21 of a sealing groove of a hydraulic device used in an embodiment of the present application. Figures 2 to 5 Different structural forms of the rough surface 21 are shown. The rough surface 21 has a strong hindering effect on the movement of the sealing ring 30 away from the cylinder body, and a relatively small hindering effect on the movement of the sealing ring 30 close to the cylinder body.

[0051] Optionally, the rough surface 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 realize the rough surface 21, such as Figure 2 As shown, a plurality of triangular protrusions are provided on the surface of the bottom side of the sealing groove facing the piston 20, and the right side of the triangular protrusion is an inclined surface, forming a structure similar to a barb, so that the protrusion has a strong hindering effect on the sealing ring 30 moving to the right, and has a small hindering effect on the sealing ring 30 moving to the left.

[0053] like Figure 3 As shown, 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 sealing ring 30 moving to the right, and a small hindering effect on the sealing ring 30 moving to the left.

[0054] like Figure 4 As shown, a plurality of stack-shaped protrusions are arranged on the lowermost side surface of the sealing groove facing the piston 20, and 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 truncated cone. The boss or truncated cone includes a connecting surface and a contact surface that are arranged opposite to each other, the connecting surface is used to connect with the sealing groove, and the contact surface is used to contact with 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 truncated cone is gradually changed, that is, the closer the diameter is to the connecting surface, the larger the diameter is, and the closer the diameter is to the connecting surface, the smaller the diameter is. The connecting surface of the truncated cone or boss has a certain contact area, which can provide the required friction force for the sealing ring.

[0056] like Figure 5 As shown, a plurality of bosses or cones are provided on the lowermost surface of the sealing groove facing the piston 20 , and the trapezoidal bosses can play a positioning role for the sealing ring 30 in contact therewith to prevent the sealing ring 30 from relative displacement.

[0057] In one embodiment of the present application, the height of the rough surface 21, i.e., the height of the protrusions, is between 0.01 and 1 mm, and the multiple protrusions are evenly distributed on the contact surface with a distribution density of 1 to 100 / cm2. Alternatively, the protrusions are arranged in rows and protrude in a ridge-like manner on the sealing groove of the piston 20 to position the sealing ring 30.

[0058] In order to better achieve the expansion of the sealing ring 30, optionally, an energizer 40 is provided in the sealing groove, the energizer 40 is placed in the sealing groove and contacts the sealing ring 30; a first notch (not shown) is provided on the energizer 40, and a second notch (not shown) is provided on the sealing ring 30, and the first notch and the second notch are arranged oppositely along the axial direction of the piston 20. By setting the positions of the first notch and the second notch, the sealing performance of the sealing ring 30 can be improved. The energizer 40 exerts a collective force on one side surface of the sealing ring 30 to push the sealing ring 30 to move. The driving difficulty is reduced, and it is convenient for the sealing ring 30 to respond in time.

[0059] In one embodiment of the present application, the energizer 40 is C-shaped, that is, a first notch is provided on the energizer 40, which is a non-closed ring. For example, the driving force provided by the pressure regulating structure acts on the energizer 40 and the sealing ring 30, so that the sealing ring 30 generates a leftward thrust, and generates a sealing pressure on the inner wall 10 of the cylinder body. The sealing pressure is equivalent to or slightly higher than the set pressure of the corresponding pressure regulating structure, thereby realizing the pressure equalization function.

[0060] After the sealing groove accommodates the sealing ring 30, the energizer 40 needs to be installed. A certain distance is kept between the energizer 40 and the sealing groove to facilitate the high-pressure liquid hydrogen 50 to act on the energizer 40. By appropriately reducing the volume of the rear space of the energizer 40 (i.e., the second gap 201), the pressure of the fluid leaked from the pressure regulating structure is transmitted more quickly, so as to apply pressure to the sealing ring 30.

[0061] Figure 6 FIG. 4 is a schematic diagram of an energizer 40 of a hydraulic device used in an embodiment of the present application. Figure 6 As shown, a positioning rod 41 is provided on the energizer 40 .

[0062] In order to make the position of the energizer 40 more stable, optionally, a positioning rod 41 is provided on the energizer 40, and a positioning hole for use with the positioning rod 41 is extended from the sealing groove, and the positioning rod 41 can move in the positioning hole; when the positioning rod 41 contacts the sealing ring 30, it is used to limit the position of the second notch of the sealing ring 30, and the second notches of adjacent sealing rings 30 are staggered. The positioning hole is connected with the sealing groove, or the positioning hole is connected with the sealing groove and the pressure regulating structure at the same time. The energizer 40 includes an inner surface and an outer surface, and the positioning rod 41 is arranged on the outer surface, located in the middle or upper middle part of the energizer 40, and extends to the side away from the energizer 40, usually in the form of a round rod. The positioning rod 41 and the first notch are respectively arranged on opposite sides of the energizer 40. The positioning rod 41 moves in the positioning hole to limit the position and movement range of the energizer 40 and the sealing ring 30 in the sealing groove. At the same time, because the movement range of the energizer 40 is limited, the energizer 40 responds to the pressure relief pressure more advantageously and more quickly.

[0063] Furthermore, when the sealing ring 30 is C-shaped, that is, the sealing ring 30 is provided with a second notch, which is a non-closed ring, after the energizer 40 is positioned by the positioning rod 41, the notch on the energizer 40 can be used to position the sealing ring 30 again by the positioning rod 41, so that the gap of the sealing ring 30 is staggered and the sealing performance is optimized. The regulating channel 22 and the positioning hole can be set to multiple, each regulating channel 22 is connected to a positioning hole, and then the multiple connected regulating channels 22 and positioning holes are evenly distributed within the circumference of the piston 20, so as to realize the positioning of the opening of the sealing ring 30, and avoid the opening of the sealing ring 30 from converging to the same angle during operation, causing a large amount of uncontrollable leakage.

[0064] Figure 7 FIG. 4 is a schematic diagram of another energizer 40 of the hydraulic device used in the embodiment of the present application. Figure 7 As shown, a notch 42 is provided on the energizer 40 .

[0065] In order to achieve a better energizing effect of the energizer 40, at least two notches 42 are optionally provided at the edge of the energizer 40, and at least two notches 42 are symmetrically provided on opposite sides of the positioning rod 41. One or more notches 42 are provided on both sides near the positioning rod 41, and the notches 42 may be semicircular in shape, or other shapes, so that the strength of this part is slightly weaker than that of other parts, and when deformed, the sealing ring 30 can be expanded outward with better roundness, thereby increasing a better energizing effect.

[0066] In order 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 can be narrowed, and the first gap 281 between the sealing ring 30 and the sealing groove can be appropriately reduced, so that the amount and speed of the high-pressure liquid hydrogen 50 leaking through the annular gap 28 flowing through the gap to the second gap 201 on the energizer 40 side are limited. Optionally, at least one vortex groove 29 is provided on at least a part of the circumferential edge of the piston 20; when the number of the vortex grooves 29 is multiple, 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 one side of the sealing groove opposite to the rough surface 21; when the number of the vortex grooves 29 is multiple, 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 a backflow and a 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] See also Figure 1Optionally, 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 arranged 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 are respectively connected to the cylinder body and the sealing groove. The first valve core is arranged in the first regulating channel 22. The first driving member is connected to the first valve core. The first driving member can drive the first valve core to open and close the first regulating channel 22. When the pressure does not reach the predetermined value, the first regulating channel 22 remains open; when the high-pressure liquid hydrogen 50 enters the first regulating channel 22, the pressure gradually increases, and the first driving member starts to drive the first valve core to move. 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 is lower than the predetermined value again, the first driving member starts to drive the first valve core to move 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 adopts a variable diameter pressure relief hole, and the first valve core adopts a ball 24. The ball 24 moves within a certain range. When the ball 24 moves to the smallest diameter, the first regulating channel 22 is closed. When the ball 24 leaves the smallest diameter, the first regulating channel 22 is opened. The first driving member adopts 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 a locking nut 26 is arranged inside. A pressure-inducing through hole 27 is arranged at the center of the locking nut 26. The opposite ends of the pressure-inducing through hole 27 are connected to the first regulating channel 22 and the cylinder body respectively; 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 the high-pressure liquid hydrogen 50 enters the first regulating channel 22, as the pressure gradually increases, the first spring 23 is compressed and the second spring 25 is stretched, so that the ball 24 moves. When the pressure reaches the predetermined value, the ball 24 moves to the smallest diameter, and the first regulating channel 22 switches from open to closed. When the pressure is lower than the predetermined value again, the first spring 23 and the second spring 25 are reset, driving the ball 24 away from the smallest diameter, and the first regulating channel 22 switches from closed to open.

[0069] There are multiple pressure relief valves, and the set closing pressure of the pressure relief valve can be selected by controlling the elastic force of the first spring 23 and the second spring 25, such as setting the closing pressures of the nine pressure relief valves from the bottom to the top of the piston 20 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, forming a uniform increase in the pressure on the sealing surface 11 of each seal, and the pressure difference between the seals is equal, so that the high-pressure liquid hydrogen 50 is sealed step by step under control.

[0070] Figure 8 This is a partial cross-sectional view of the hydraulic device used in the second embodiment of the present application. Figure 8 and Figure 1 The main difference is that the structures of the valve core and the driving member are different, and there is a guide ring mounting groove 70. The first valve core adopts a T-shaped valve core 60, and the first driving member adopts a third spring 61. The third spring 61 is sleeved on the valve core 60, and the valve core 60 can be close to the locking nut 26, and the third spring 61 can abut on the first channel diameter reducing section. When the pressure does not reach the predetermined value, the third spring 61 pushes the valve core 60 to approach the locking nut 26, and the first regulating channel 22 remains open; when the high-pressure liquid hydrogen 50 enters the first regulating channel 22, the pressure gradually increases, pushing the valve core 60 to move upward and begin to compress the third spring 61; when the pressure reaches the predetermined value, the third spring 61 is further compressed, the valve core 60 moves to the smallest diameter, and the first regulating channel 22 switches from open to closed. When the pressure is lower than the predetermined value again, the third spring 61 resets, driving the valve core 60 to leave the smallest diameter, and the first regulating channel 22 switches from closed to open. The guide ring installation groove 70 is provided on the piston 20 for installing the guide ring. The guide ring ensures the accuracy of the movement of the piston 20 and avoids excessive deviation that affects the sealing of the piston 20.

[0071] In addition to the above-mentioned implementation method, the pressure regulating structure can also be implemented in another way. Fig. 9 FIG. 1 is a partial cross-sectional view of the hydraulic device used in the third embodiment of the present application. Fig. 9 As shown, the pressure regulating structure includes a second regulating channel 22, a second valve core and a second driving member.

[0072] Fig. 9 The second regulating channel 22 shown is Figure 1 The difference between the structures of the first regulating channel 22 shown is that the first regulating channel 22 is directly connected to the sealing groove, and the second regulating 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 regulating structure includes a second regulating channel 22, a second valve core and a second driving member. The second regulating channel 22 is arranged on the piston 20. The second regulating channel 22 includes a second inlet end and at least one second outlet end. The second inlet end is communicated with the cylinder body, and the second outlet end is communicated with the gap between two adjacent sealing grooves. The second valve core is arranged in the second regulating channel 22, and the second driving member can drive the second valve core to open and close the second regulating channel 22. The second outlet end of the second regulating channel 22 of the pressure regulating structure is arranged between two adjacent sealing grooves, that is, the second outlet end of the second regulating channel 22 is arranged in the annular gap 28 between two sealing rings 30. When the pressure does not reach the predetermined value, the second regulating channel 22 remains open; when the high-pressure liquid hydrogen 50 enters the second regulating channel 22, the pressure gradually increases, and the second driving member starts to drive the second valve core to move. When the pressure reaches the predetermined value, the second driving member and the second valve core close the second regulating channel 22. When the pressure is lower than the predetermined value again, the second driving member starts to drive the second valve core to move again.

[0074] The pressure relief fluid of the predetermined pressure directly relieves the pressure in the annular gap 28 between two adjacent sealing rings 30, so that the pressure in the annular gap 28 between each sealing ring 30 is the set pressure, and the pressure difference between the upper and lower sides of each sealing ring 30 is a set pressure difference. During the movement of the piston 20, the pressure distribution between the two adjacent sealing rings 30 is distributed according to the set value, and is balanced with the pressure of the fluid flowing from the annular gap 28 between the piston 20 and the inner wall 10. The residual pressure after balance is the final sealing pressure. The residual pressure is a smaller value after the pressure on the lower side offsets the pressure on the upper side. For example, the pressure difference of each seal can be set to 5MPa.

[0075] Fig.10 FIG. 1 is a partial cross-sectional view of the hydraulic device used in the fourth embodiment of the present application. Fig.10 As shown, Fig.10 and Fig. 9 The main difference is that the piston 20 is provided with a vortex groove 29.

[0076] In order 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 body (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 along the axial direction are provided on the circumferential edge of the piston 20, and / or a plurality of vortex grooves 29 spaced along the radial direction are provided on the surface of the bottom side of the sealing groove facing away from the piston 20. The flow rate of the fluid flowing from the first gap 28 is limited by the vortex grooves 29, 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, the pressure on the upper side is offset, and 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 more 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] Fig.11 Schematic diagram of the correlation between pressure and time during the 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; t3 is the sealing time.

[0079] like Fig.11 As shown, the piston 20 in the liquid hydrogen compression stroke can be summarized as "first pressure equalization, then positioning, and then sealing".

[0080] There are ten seals on the piston 20, and the sealing grooves and the sealing rings 30 cooperate with each other to provide sealing 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 pressure regulating structures, namely pressure relief valves. The pressure relief pressures set by the spring elastic force in the pressure relief valves corresponding to the first nine seals are 5MPa, 10MPa, 15MPa, 20MPa, 25MPa, 30MPa, 35MPa, 40MPa, and 45MPa, respectively.

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

[0082] During the compression stroke of liquid hydrogen, the high pressure of 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, so that the sealing ring 30 is closely attached to the rough surface 21 of the sealing groove. The rough surface 21 provides a large static friction force, so that the sealing ring 30 cannot move, realizing the positioning function.

[0083] In the compression stroke of liquid hydrogen, due to the reduction of the first gap 281 and the obstruction of the vortex groove 29, the amount and speed of the sealing ring 30 flowing from the annular gap 28 to the first gap 281 and the second gap 201 are limited. In addition, due to the reduction of the volume of the second gap 201, the pressure leakage from the pressure relief valve is transmitted more quickly, and the sealing thrust of the sealing ring 30 to the left is mainly driven by the pressure of the high-pressure liquid hydrogen 50 leaking from the pressure relief valve. After the high-pressure liquid hydrogen 50 flowing from the annular gap 28 flows to the second gap 201, due to the positioning effect of the rough surface 21, the high pressure in the second gap 201 cannot push the sealing ring 30 to continue to move toward the cylinder wall, but the high pressure in the second gap 201 can offset the reaction force of the high-pressure liquid hydrogen 50 leaking from the sealing surface 11 on the sealing ring 30, ensuring that the sealing ring 30 cannot move away from the cylinder wall, and ensuring that the seal does not fail completely.

[0084] Since the sealing pressure on the previous sealing surface 11 is lower than the pressure of the high-pressure liquid hydrogen 50, a portion of the high-pressure liquid hydrogen 50 will leak along the sealing surface 11 to the next seal (upward). However, the leaked high-pressure liquid hydrogen 50 cannot push the sealing ring 30 to move to the right to completely fail the seal. It can only leak upward from the gap of the sealing surface 11, so the seal still works, but it is not enough to seal it completely. The leaked 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 on the 9 seals in the above leakage process, good self-lubrication is achieved while making the wear of all the sealing rings 30 close to the same.

[0085] The sealing ring 30 relies on the high-pressure liquid hydrogen 50 for self-lubrication and needs to be infiltrated with 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 known that the hydraulic device provided by the present application has the following advantages compared with the prior art: the above hydraulic device is adopted, and 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 according to the change of the pressure in the cylinder body, so as to provide the functions of sealing, lubrication and pressure equalization respectively. The sealing ring 30 of the piston realizes the sealing function; after the pressure of the previous seal (such as the first seal) of the piston 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, and the gap between the sealing ring 30 and the inner wall of the cylinder body will have a part of the high-pressure liquid hydrogen 50 leaking 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 it is not enough to seal all. 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 all the liquid hydrogen pressure together. While achieving sealing, the backward sliding amount of liquid hydrogen is minimized, and the uniform sealing pressure makes the wear of multiple sealing rings 30 the same. The leaked liquid hydrogen forms a good self-lubricating agent on the surface of the sealing ring 30, which greatly reduces the wear of the sealing ring 30, prolongs its service life, extends the maintenance cycle, and reduces costs.

[0087] A person 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 substitutions, improvements, etc. made within the scope of the present application should be included in the protection scope 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, the pressure regulating structure being capable of driving the sealing ring to move in the sealing groove to adjust the gap between the sealing ring and the cylinder body; 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 to drive the sealing ring in the sealing groove of the piston to move from bottom to top in sequence; 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.

2. The hydraulic device according to claim 1, characterized in that: A surface of the sealing groove on one side facing the lowermost side of the piston is arranged to be a rough surface.

3. The hydraulic device according to claim 2, characterized in that: The rough surface is a plurality of protrusions arranged at equal intervals along the radial direction.

4. The hydraulic device according to claim 3, characterized in that: The protrusion is in the form of an inverted boss or a frustum.

5. The hydraulic device according to claim 2, 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.

6. The hydraulic device according to claim 5, 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.

7. The hydraulic device according to claim 6, 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.

8. The hydraulic device according to claim 2, 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.

9. The hydraulic device according to claim 1, 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.

10. The hydraulic device according to claim 1, 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.

Images