Hydraulic active suspension system with adjustable damping and oil-gas separation

Abstract

The application provides an oil-gas separation type damping adjustable hydraulic active suspension system, which comprises a shock absorber, an energy accumulator, a power module and an elastic element; the inside of the shock absorber is filled with oil, and the side part is provided with a hydraulic pipeline joint; the energy accumulator comprises a shell; the inside of the shell is separated into a gas chamber and a liquid chamber by a diaphragm, the gas chamber is filled with high-pressure gas, and the liquid chamber is filled with oil; the power module comprises a motor pump, an oil storage pot and a switch valve; the energy accumulator is connected with the hydraulic pipeline joint and the motor pump through a three-way pipeline; the switch valve is arranged on the pipeline between the motor pump and the energy accumulator; the motor pump and the switch valve are connected with an ECU signal; during operation, the motor pump and the switch valve are opened under the control of the ECU, the oil in the oil storage pot is extracted to the shock absorber through the motor pump, the piston rod is driven to move outward to lift the vehicle body, or the oil in the shock absorber is extracted to retract the piston rod inward to lower the vehicle body, so that the active adjustment of the vehicle body height is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automobile parts, and particularly relates to an oil-gas separation type damping adjustable hydraulic active suspension system. BACKGROUND

[0002] A vehicle suspension is connected between a wheel and a vehicle body, and undertakes the core task of buffering and damping, and is a key component that affects the comfort, control stability and safety of a vehicle. A traditional vehicle suspension adopts a combined form of a coil spring and a shock absorber. In use, the coil spring and the shock absorber are respectively connected between the vehicle body and the tire, the coil spring bears and stores energy to avoid rigid impact, and the shock absorber consumes energy to suppress the excessive oscillation of the spring, so as to improve the driving stability and safety. However, due to the physical characteristics of the coil spring, the traditional vehicle suspension cannot actively adjust the vehicle body height. In order to overcome this limitation, engineers have developed an air suspension, which uses an air spring (a rubber air bag filled with compressed air inside) to replace the traditional coil spring, and adjusts the vehicle body height and the suspension softness by filling or releasing air into the air bag. This is also the mainstream suspension with lifting function on the market at present. However, the air suspension has the following defects due to its structure: ①The bag skin of the air spring is prone to aging (especially the service life will be shortened by 30%-50% in high temperature environment), and the sealing performance will decay with the use time, resulting in a gradual decrease in the vehicle body height; ②The fault tolerance is poor: after the compressor fails, the gas in the air bag will slowly leak, and the vehicle body will soon lose support, resulting in the vehicle being unable to continue driving; and the air bag skin rupture will also cause the suspension to completely fail and be unable to support the vehicle body; ③The gas compressibility is large, the system response delay is greater than or equal to 0.3 seconds, the vehicle body height adjustment speed is slow, and the road conditions cannot be adapted in real time. SUMMARY

[0003] The application provides an oil-gas separation type damping adjustable hydraulic active suspension system, which is used for solving the above problems in the prior art. The oil-gas separation type damping adjustable hydraulic active suspension system can be adapted to suspension forms such as MacPherson, double wishbone and multi-link. The system comprises a shock absorber, an accumulator and a power module matched with the shock absorber. The power module comprises a motor pump and an oil storage pot. During use, the motor pump can be used to charge and discharge oil in the shock absorber according to actual working conditions, so as to control the extension and retraction of the piston rod and realize active adjustment of the height of the vehicle body. The specific structure design enables the suspension to maintain basic functions when a certain component fails, so that the vehicle can continue to run in a failure mode, and the fault tolerance is high. Moreover, the application realizes oil pressure compensation through the accumulator, cancels the oil-gas mixing cavity of the traditional shock absorber, and only retains pure oil working medium, so that the emulsification problem caused by direct contact between oil and gas in the traditional oil-gas mixing structure can be solved from the root, the dynamic response speed of the system is improved, and the height adjustment speed of the vehicle body is fast. In addition, the accumulator adopts an independent external structure design, which does not occupy the space under the spring, so that the mass under the spring can be reduced.

[0004] The technical scheme of the application is as follows: an oil-gas separation type damping adjustable hydraulic active suspension system comprises a shock absorber, an elastic element, and an accumulator and a power module matched with the shock absorber. The inside of the shock absorber is filled with oil. The side of the shock absorber is provided with a hydraulic pipeline joint. The accumulator comprises a shell, the inside of the shell is separated into a gas chamber and a liquid chamber through a diaphragm, the gas chamber is filled with high-pressure gas, the liquid chamber is filled with oil, the power module comprises a motor pump, an oil storage pot and a switch valve, the accumulator is connected with the hydraulic pipeline joint and the motor pump through a three-way pipeline, the switch valve is arranged on the pipeline between the motor pump and the accumulator, the motor pump and the switch valve are connected with an ECU signal, and the motor pump and the switch valve are opened under the control of the ECU. During work, the oil in the oil storage pot is extracted into the shock absorber by the motor pump, so as to push the piston rod to move outward and lift the vehicle body, or the oil in the shock absorber is extracted, so as to retract the piston rod inward and lower the vehicle body.

[0005] Compared with the prior art, the oil-gas separation type damping adjustable hydraulic active suspension system has the following advantages: (1) The suspension system comprises a shock absorber, an accumulator matched with the shock absorber and a power module, and the power module comprises a motor pump and an oil storage pot. During use, corresponding instructions can be set in the ECU according to actual working conditions, the motor pump is controlled to charge and discharge oil into the shock absorber, the piston rod is pushed to move outward or the piston rod is retracted inward, and the active adjustment of the vehicle body height is realized. The specific structural design enables the suspension to still maintain the basic function when a certain component fails (for example, when a certain component of the power module fails, the entire system can still be used as an ordinary shock absorber, but no longer has the lifting function; or when the accumulator diaphragm is broken, the shock absorber can still support the vehicle body by relying on the elastic element), so that the vehicle can continue to run in the failure mode, and the fault tolerance is high; (2) The oil-gas separation type damping adjustable hydraulic active suspension system realizes oil pressure compensation through an external accumulator, cancels the oil-gas mixing chamber of the traditional shock absorber, and only retains pure oil working medium, so that the emulsification problem caused by the direct contact between oil and gas in the traditional oil-gas mixing structure can be solved from the root; experiments show that the oil gas rate can be stably controlled to be ≤0.1%, the damping force fluctuation amplitude is ≤±5% (-30℃-80℃ full temperature range), the interference caused by gas dissolution / dissolution can be avoided, the oil volume elastic modulus is stable (≥1.8×10³MPa), the system dynamic response delay can be compressed to ≤0.08s, the response speed of the traditional oil-gas mixing suspension can be improved by 60%, so that the vehicle body height adjustment speed can be improved; in addition, the accelerated aging of the sealing element caused by oil-gas mixing can be avoided, and the sealing life of the shock absorber can be prolonged by more than 2 times; (3) The accumulator adopts an independent external structure design, which does not occupy the space under the spring, so that the mass under the spring can be reduced by 8%-12%, so that the transmission of road impact to the vehicle body can be reduced, and the vehicle riding comfort can be improved; (4) The application range is wide, and the suspension form such as the McPherson, double wishbone and multi-link can be matched.

[0006] As an optimization, the oil-gas separation type damping adjustable hydraulic active suspension system further comprises a height sensor matched on the vehicle, for monitoring the vehicle body height. Therefore, when the vehicle body height is adjusted, the motor pump and the on-off valve are closed by the ECU when the height sensor detects that the vehicle body height reaches the set value, and the adjustment accuracy is high. In addition, for scenes such as loading heavy load (such as the sinking of the rear load of a commercial vehicle), the ECU can monitor the vehicle body posture in real time through the height sensor, automatically charge and discharge oil into the corresponding shock absorber, realize the vehicle body level adjustment (leveling accuracy ±2mm), and ensure the driving safety and riding convenience.

[0007] As an optimization, the oil-gas separation type damping adjustable hydraulic active suspension system further comprises a vehicle speed sensor arranged on the vehicle, which is used for monitoring the driving speed of the vehicle and transmitting a signal to the ECU, and the ECU controls the motor pump and the on-off valve to open according to the received driving speed, adjusts the height of the vehicle body, and improves the fuel economy.

[0008] As an optimization, the oil-gas separation type damping adjustable hydraulic active suspension system further comprises that the high-pressure gas filled in the gas chamber is high-pressure nitrogen. The high-pressure nitrogen is stable in chemical properties and is not easy to cause oxidation reaction with the shell and the diaphragm, so that the durability of the accumulator is longer.

[0009] As an optimization, the oil-gas separation type damping adjustable hydraulic active suspension system further comprises that the shock absorber is a double-cylinder electric control shock absorber, which comprises a liquid storage cylinder and a working cylinder arranged in the liquid storage cylinder; the side of the liquid storage cylinder is provided with an electromagnetic valve connected with the ECU signal; the liquid inlet and the liquid outlet of the electromagnetic valve are respectively connected with the working cylinder and the internal cavity of the liquid storage cylinder; and the working current of the electromagnetic valve is controlled by the ECU during working to adjust the opening of the electromagnetic valve and adjust the damping force. Thus, the damping force parameter can be matched synchronously while the height of the vehicle body is adjusted, the height-damping collaborative control is realized, and the vehicle control stability and the ride comfort are optimized (for example, the damping force is increased when the vehicle body is raised to improve the support, and the damping force is reduced when the vehicle body is lowered to improve the comfort). In addition, compared with the traditional double-cylinder electric control shock absorber, the double-cylinder electric control shock absorber of the application does not arrange an intermediate cylinder, the structure is simplified, the weight is lighter, and the sealing points are less, so that the reliability is higher.

[0010] Further, the side of the liquid storage cylinder is provided with a pipe sleeve; the hydraulic pipeline joint is fixed by thread connection with the pipe sleeve, and a sealing ring is arranged between the hydraulic pipeline joint and the pipe sleeve. At this time, the structure is simple and the assembly is convenient.

[0011] Further, the top of the cartridge is provided with a dynamic sealing assembly; the dynamic sealing assembly comprises a lower guide, a middle guide and an upper guide which are sequentially sleeved on the piston rod; the upper guide is provided with a sealing ring between the upper guide and the inner wall of the cartridge and a high-pressure oil seal between the upper guide and the piston rod; the middle guide is provided with a sealing ring between the middle guide and the inner wall of the cartridge and two upper and lower distributed stellite seals between the middle guide and the piston rod; the lower guide is sealingly connected with the top end of the working cylinder, and a guide bushing is arranged between the lower guide and the piston rod. At this time, the inner side of the shock absorber adopts the above-mentioned three-level sealing structure to ensure the sealing performance of the piston rod under high hydraulic pressure environment, and adopts the stellite seal structure to improve the sealing life, and the outer side seals the guide through the sealing ring, so that the risk of oil leakage under high hydraulic pressure working condition can be reduced by 90%. Further, there is a liquid flow channel between the outer side surface of the lower guide and the inner wall of the cartridge. Through the pressure generated by the oil flowing into the inside of the dynamic sealing assembly from the liquid flow channel, the sealing performance and the compactness of the dynamic sealing assembly can be further strengthened, and the implementation difficulty is reduced.

[0012] Further, the stellite seal comprises a polytetrafluoroethylene ring and an O-ring sleeved outside the polytetrafluoroethylene ring; the polytetrafluoroethylene ring is in a stepped shape. In the initial sealing stage, the O-ring is pre-compressed to generate an initial contact stress, the polytetrafluoroethylene ring is micron-level (≤5 μm) fitted with the surface of the piston rod, and no-pressure sealing is realized; in the pressure acting stage, for every 1 MPa increase in hydraulic pressure, the O-ring expands radially to make the contact stress between the polytetrafluoroethylene ring and the piston rod increase by 0.8-1.2 MPa, while a steep pressure gradient is formed on the high-pressure side and a “pump back suction” effect is generated on the low-pressure side, reducing oil residue.

[0013] Further, the upper end of the upper guide is provided with an end cover for tightly pressing and positioning the dynamic sealing assembly in the shock absorber from the outside; the end cover is fixed with the top end of the cartridge through threaded connection. At this time, the assembly is convenient and the implementation difficulty is low.

[0014] Further, a plurality of through holes are formed in the top and side of the end cover. Thus, the dust and moisture scraped down by the high-pressure oil seal can be discharged from the through holes, avoiding the accumulation of impurities inside the end cover; and the through holes can also be used for balancing the internal and external pressures to ensure smooth movement of the piston rod. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic diagram of the oil-gas separation type damping adjustable hydraulic active suspension system of the present application;

[0016] Figure 2 is a cross-sectional schematic diagram of the accumulator in the present application;

[0017] Figure 3 is a state diagram of the accumulator diaphragm when the vehicle body is lifted;

[0018] Figure 4 is the state diagram of the accumulator diaphragm when the height of the vehicle body is reduced;

[0019] Figure 5 is a structural schematic diagram of a double-cylinder electric control shock absorber in the embodiment of the application;

[0020] Figure 6 is a sectional schematic diagram of a double-cylinder electric control shock absorber in the embodiment of the application;

[0021] Figure 7 is a schematic diagram of a dynamic sealing assembly in the embodiment of the application;

[0022] Figure 8 is a state diagram of the accumulator diaphragm under two strokes of the shock absorber, namely, recovery and compression;

[0023] Figure 9 is a schematic diagram of the oil flow when the shock absorber piston rod is compressed;

[0024] Figure 10 is a schematic diagram of the oil flow when the shock absorber piston rod is recovered.

[0025] The marks in the drawings are as follows: 1 - shock absorber, 101 - liquid flow channel, 11 - piston rod, 12 - electromagnetic valve, 13 - liquid storage cylinder, 131 - pipe sleeve, 14 - working cylinder, 15 - dynamic sealing assembly, 151 - lower guide, 152 - middle guide, 153 - upper guide, 154 - high-pressure oil seal, 155 - Stell seal, 156 - guide bushing, 157 - end cover, 158 - gasket, 16 - piston valve, 17 - bottom valve, 18 - bottom cover; 2 - accumulator, 201 - gas chamber, 202 - liquid chamber, 21 - shell, 22 - diaphragm; 3 - power module, 31 - motor pump, 32 - oil storage pot, 33 - on-off valve; 4 - hydraulic pipeline joint; 5 - three-way pipeline; 6 - elastic element. DETAILED DESCRIPTION

[0026] The application builds a high-performance self-adaptive oil-gas separation type damping adjustable hydraulic active suspension system through the collaborative design of three core modules, namely, a dynamic sealing structure, an oil-gas separation structure and an active height adjustment structure. The application will be further described below in combination with the drawings and embodiments, but it is not used as the basis for limiting the application. The contents not described in detail in the following embodiments are all the technical common sense in the art.

[0027] Referring to Figure 1 and Figure 2The oil-gas separation type damping adjustable hydraulic active suspension system of the application comprises a shock absorber 1, an elastic element 6, an energy accumulator 2 and a power module 3 matched with the shock absorber 1; the inside of the shock absorber 1 is filled with oil (hydraulic oil with viscosity grade ISO VG46 and viscosity index ≥140); the side of the shock absorber 1 is provided with a hydraulic pipeline joint 4; the energy accumulator 2 comprises a shell 21, the inside of the shell 21 is separated into a gas chamber 201 and a liquid chamber 202 (the volume can be designed as 1-2L according to the load of the vehicle type) by a diaphragm 22 (fluorine rubber material can be used, sealing level IP6K9K); the gas chamber 201 is filled with high-pressure gas (pre-charge pressure 0.8-1.2MPa); the liquid chamber 202 is filled with oil; the power module 3 comprises a motor pump 31, an oil storage pot 32 (the effective volume of the oil storage pot 32 can be set as 8-15L, which is suitable for different load requirements of passenger cars, commercial vehicles and the like; an oil filter core is built-in, and the filtering precision is 10μm) and an on-off valve 33; the energy accumulator 2 is connected with the hydraulic pipeline joint 4 and the motor pump 31 respectively through a three-way pipeline 5 (pressure resistance ≥35MPa, the diameter can be 12mm); the on-off valve 33 is arranged on the pipeline between the motor pump 31 and the energy accumulator 2; the motor pump 31 and the on-off valve 33 are connected with the ECU signal respectively. In use, the two ends of the shock absorber 1 and the elastic element 6 (the elastic element can be a coil spring or an air spring) are connected with the vehicle body and the tire respectively; the energy accumulator 2 is independently arranged on the side beam of the vehicle frame (non-spring area); the power module 3 is reasonably configured according to the space layout of different vehicle types, and can be arranged at the front, middle and rear of the vehicle. In work, according to the actual working condition, the corresponding instructions are set in the ECU, the motor pump 31 and the on-off valve 33 are opened by the ECU control, the oil in the oil storage pot 32 is extracted to the shock absorber 1 through the motor pump 31, so as to push the piston rod 11 to move outward to lift the vehicle body (for example, the vehicle body is lifted by 20-50mm to increase the ground clearance in off-road conditions), or the oil in the shock absorber 1 is extracted to retract the piston rod 11 inward to lower the vehicle body (for example, the vehicle body is lowered to the lowest ground clearance when parking).

[0028] Further, the aforementioned oil-gas separation type damping adjustable hydraulic active suspension system further comprises a height sensor and a vehicle speed sensor arranged on the vehicle. The height sensor is used to monitor the height of the vehicle body and transmit signals to the ECU. When adjusting the height of the vehicle body, when the height sensor detects that the height of the vehicle body reaches the set value, the ECU controls the motor pump 31 and the on-off valve 33 to be closed; for the scene of loading heavy load, etc., the ECU can monitor the posture of the vehicle body in real time through the height sensor, and automatically charge and discharge oil to the corresponding shock absorber (for example, when the rear load of the commercial vehicle is lowered, the shock absorber on the rear tire can be filled with oil to lift the rear vehicle body), so as to realize the horizontal leveling of the vehicle body (the leveling accuracy is ±2mm), and to ensure the driving safety and the convenience of riding. The vehicle speed sensor is used to monitor the driving speed of the vehicle and transmit signals to the ECU; the ECU controls the motor pump 31 and the on-off valve 33 to be opened according to the received driving speed, and adjusts the height of the vehicle body. For example, during high-speed driving, when the ECU receives the driving speed exceeding 100km / h, the motor pump 31 and the on-off valve 33 are controlled to be opened, the oil in the shock absorber 1 is pumped out through the motor pump 31, the piston rod 11 is withdrawn inward, and the height of the vehicle body is lowered (15-30mm) to reduce the wind resistance and improve the fuel economy.

[0029] In the present application, the core of the vehicle body height lifting principle is to change the oil volume in the shock absorber. The lifting principle is as follows: the ECU sends a command to open the on-off valve and the motor pump is turned on---the oil is pumped into the shock absorber---the total volume of the oil in the shock absorber increases---the piston rod is pushed outward---the height sensor detects that the height of the vehicle body reaches the set value---the ECU sends a command to close the on-off valve and the motor pump; the lowering principle is as follows: the ECU sends a command to open the on-off valve and the motor pump is reversed---the oil flows out of the shock absorber---the total volume of the oil in the shock absorber decreases---the piston rod is withdrawn inward---the height sensor detects that the height of the vehicle body reaches the set value---the ECU sends a command to close the on-off valve and the motor pump. Specifically as follows.

[0030] ①The ECU sends a height lifting command to control the on-off valve 33 to be opened, so that the shock absorber 1 is communicated with the oil storage pot 32 through the motor pump 31. The ECU controls the motor pump 31 to be turned on, the motor pump 31 pumps the oil in the oil storage pot 32, and the oil is pumped into the shock absorber 1 through the three-way pipe 5 and the hydraulic pipe joint 4; at this time, the total oil volume in the shock absorber 1 increases, the pressure of the oil increases, the piston rod 11 is pushed out of the shock absorber 1; the lifting force applied to the vehicle body by the piston rod 11 increases, the height of the vehicle body is lifted. The elastic element 6 between the vehicle body and the tire is stretched under reduced stress; the piston rod 11 is stressed, and the pressure of the oil applied to the piston rod 11 also increases; the increased pressure makes the oil in the accumulator 2 push the diaphragm 22 to move upward, the volume of the high-pressure gas decreases, the pressure increases, and the pressure received by the piston rod 11 after the height of the vehicle body is lifted reaches the balance, as shown in Figure 3The height sensor sends a signal to the ECU when the height of the vehicle body reaches the set height, and the ECU sends a command to close the motor pump 31 and the on-off valve 33, disconnecting the shock absorber 1 from the oil reservoir 32 and maintaining the height of the vehicle body.

[0031] When the ECU sends a height-lowering command, the on-off valve 33 is opened, and the shock absorber 1 is connected to the oil reservoir 32 through the motor pump 31. The ECU controls the motor pump 31 to reverse, and the motor pump 31 draws oil from the shock absorber 1 through the three-way pipeline 5 and the hydraulic pipeline joint 4 and pumps it back into the oil reservoir 32. At this time, the total volume of oil in the shock absorber 1 decreases, and the piston rod 11 is pressed back into the shock absorber 1 under the weight of the vehicle body. When the height of the vehicle body decreases, the elastic element 6 supporting the vehicle body starts to compress, the force on the piston rod 11 decreases, and the pressure it exerts on the oil also decreases. The decrease in oil pressure causes the high-pressure gas in the accumulator 2 to push the diaphragm 22 downward, increasing the volume of the high-pressure gas and reducing its pressure, and the pressure on the piston rod 11 in the oil reaches equilibrium, as shown in FIG. 2B. Figure 4 The height sensor sends a signal to the ECU when the height of the vehicle body reaches the set height, and the ECU sends a command to close the motor pump 31 and the on-off valve 33, disconnecting the shock absorber 1 from the oil reservoir 32 and maintaining the height of the vehicle body.

[0032] Embodiment:

[0033] In this embodiment, the high-pressure gas filled in the gas chamber 201 is high-pressure nitrogen.

[0034] Referring to FIGS. 1A and 1B, Figure 5 and Figure 6 In this embodiment, the shock absorber 1 is a double-cylinder electrically controlled shock absorber, which includes a liquid storage cylinder 13 and a working cylinder 14 arranged inside the liquid storage cylinder 13. The working cylinder 14 is provided with a piston rod 11, the upper end of which extends out of the top of the liquid storage cylinder 13, and the lower end of which is provided with a piston valve 16. The bottom of the working cylinder 14 is provided with a bottom valve 17. The top of the liquid storage cylinder 13 is provided with a dynamic sealing assembly 15, the bottom is sealed by a bottom cover 18, and the side is provided with an electromagnetic valve 12 (with a diameter of 6 mm and a response time of ≤0.05 s) and a pipe sleeve 131. The inlet and outlet of the electromagnetic valve 12 are respectively connected to the inside of the working cylinder 14 and the liquid storage cylinder 13. The hydraulic pipeline joint 4 is fixedly connected to the pipe sleeve 131 by threading, and a sealing ring is arranged between the hydraulic pipeline joint 4 and the pipe sleeve 131. The bottom valve 17 and the piston valve 16 are both provided with through holes for the flow of oil.

[0035] When working, the ECU controls the energizing current of the electromagnetic valve 12 to adjust the opening of the electromagnetic valve 12 and adjust the damping force. Thus, the damping force parameter can be matched synchronously while the height of the vehicle body is adjusted, the height-damping collaborative control is realized, and the vehicle handling stability and ride comfort are optimized. The electric control damping force adjustment principle is as follows.

[0036] ①Referring to Figure 9 , when the shock absorber is compressed, the piston rod 11 moves downward, and the volume of the inner cavity (the internal cavity of the working cylinder 14) decreases. The oil below the piston valve 16 flows to the outer cavity (the cavity between the working cylinder 14 and the reservoir 13) through the bottom valve 17, and part of the oil flows to the space above the piston valve 16 through the piston valve 16, and then flows to the electromagnetic valve 12 (the electromagnetic valve 12 controls the damping force generated by the oil) through the flow-through hole of the working cylinder 14, and then flows out from the electromagnetic valve 12 to the outer cavity; the oil flowing to the outer cavity flows to the accumulator 2 through the hydraulic pipe joint 4 and the three-way pipe 5; the diaphragm 22 in the accumulator 2 is pushed up by the pressure, the high-pressure nitrogen gas is compressed, the space of the liquid chamber 202 is increased, and the oil is temporarily filled in the liquid chamber 202, as shown by b in Figure 8 .

[0037] ②Referring to Figure 10 , when the shock absorber is recovered, the piston rod 11 moves upward, the volume of the inner cavity above the piston valve 16 decreases, and the volume of the inner cavity below the piston valve 16 increases. Part of the oil above the piston valve 16 flows to the space below the piston valve 16 through the piston valve 16, and part of the oil flows to the electromagnetic valve 12 (the electromagnetic valve 12 controls the damping force generated by the oil) through the flow-through hole of the working cylinder 14, and then flows out from the electromagnetic valve 12 to the outer cavity; the oil flowing to the outer cavity is supplemented to the space below the piston valve 16 through the bottom valve 17; the reduced oil in the outer cavity is supplemented by the accumulator 2 through the three-way pipe 5 and the hydraulic pipe joint 4, the hydraulic pressure in the accumulator 2 decreases, the high-pressure nitrogen gas pushes the diaphragm 22 to move downward, and the oil in the liquid chamber 202 is pushed to flow to the outer cavity of the shock absorber 1, as shown by a in Figure 8 .

[0038] Referring to Figure 7In the embodiment, the dynamic sealing assembly 15 includes a lower guide 151, a middle guide 152 and an upper guide 153 which are sequentially sleeved outside the piston rod 11; the upper guide 153 is provided with a sealing ring between the inner wall of the liquid cylinder 13 and the piston rod 11, and is provided with a high-pressure oil seal 154 between the piston rod 11; the middle guide 152 is provided with a sealing ring between the inner wall of the liquid cylinder 13 and the piston rod 11, and is provided with two upper and lower distributed stellite seals 155 between the piston rod 11; the lower guide 151 is sealingly connected to the top end of the working cylinder 14, and is provided with a guide bushing 156 between the lower guide 151 and the piston rod 11. At this time, the inside of the shock absorber 1 adopts the above-mentioned three-level sealing structure (the first level sealing of the lower stellite seal, the second level sealing of the upper stellite seal, and the third level sealing of the high-pressure oil seal) to ensure the sealing performance of the piston rod 11 under high hydraulic pressure environment, and the stellite seal structure is adopted to improve the sealing life, and the outside is sealed by the sealing ring (first sealed by the lower sealing ring, and the oil leaked slightly under high pressure is sealed by the upper sealing ring), so that the risk of oil leakage under high hydraulic pressure can be reduced by 90%. Further, there is a liquid flow channel 101 between the outer side surface of the lower guide 151 and the inner wall of the liquid cylinder 13. The pressure generated by the oil flowing into the inside of the dynamic sealing assembly 15 from the liquid flow channel 101 can further strengthen the sealing performance and compactness of the dynamic sealing assembly 15, and reduce the implementation difficulty.

[0039] Further, the stellite seal 155 includes a polytetrafluoroethylene ring and an O-ring sleeved outside the polytetrafluoroethylene ring; the polytetrafluoroethylene ring is in a stepped shape. In the initial sealing stage, the O-ring is pre-compressed to generate an initial contact stress, the polytetrafluoroethylene ring is micron-level (≤5 μm) fitted with the surface of the piston rod 11, and pressureless sealing is realized; in the pressure acting stage, for every 1 MPa increase in hydraulic pressure, the O-ring expands radially to increase the contact stress between the polytetrafluoroethylene ring and the piston rod 11 by 0.8-1.2 MPa, while a steep pressure gradient is formed on the high-pressure side A, and a "pump back suction" effect is generated on the low-pressure side B, reducing oil residue.

[0040] The O-ring is made of temperature-resistant fluororubber (-40℃-120℃) (cross-sectional size 3x3mm); the polytetrafluoroethylene ring is a thin-walled annular (thickness 2mm, inner diameter matched with the diameter of the piston rod 11). The guide is made of ceramic-coated metal material (base material 304 stainless steel, coating thickness 0.1mm). The inner diameter of the upper guide 153 and the middle guide 152 is 0.05mm larger than the diameter of the piston rod 11, and the outer diameter is in interference fit with the inner wall of the liquid cylinder 13 (interference amount 0.03mm).

[0041] Further, the upper guide 153 is provided with an end cover 157, the end cover 157 is fixed with the top end of the liquid storage cylinder 13 through threaded connection; the end cover 157 and the upper guide 153 are provided with a gasket 158. At this time, the assembly is convenient, and the implementation difficulty is low. The top and side of the end cover 157 are provided with a plurality of through holes. Thus, the dust and moisture scraped by the high-pressure oil seal 154 can be discharged from the through holes, avoiding the accumulation of impurities inside the end cover 157; and the through hole can also be used for balancing the internal and external pressure, ensuring the smooth movement of the piston rod 11.

[0042] Of course, in the oil-gas separation type adjustable hydraulic active suspension system of the present application, the shock absorber can be not only a double-cylinder shock absorber, but also a single-cylinder shock absorber. Whether it is a double-cylinder shock absorber or a single-cylinder shock absorber, as long as the hydraulic pipeline joint 4 is communicated with the chamber below the piston valve 16, it is OK. In the double-cylinder shock absorber of the above embodiment, the hydraulic pipeline joint 4 is communicated with the inner cavity of the liquid storage cylinder 13, and the inner cavity of the liquid storage cylinder 13 is communicated with the chamber below the piston valve 16 through the bottom valve 17. When the shock absorber 1 is a single-cylinder shock absorber, the hydraulic pipeline joint 4 is arranged at the lower end of the shock absorber cylinder and is communicated with the chamber below the piston valve inside the cylinder.

[0043] The general description of the invention involved in the present application and the description of the specific embodiments should not be understood as a limitation of the technical solutions of the invention. Based on the disclosure of the present application, the skilled in the art can add, reduce or combine the disclosed technical features in the general description or / and the specific embodiments (including examples) without violating the elements of the invention involved, to form other technical solutions within the protection scope of the present application.

Claims

1. A hydro-pneumatic active suspension system with adjustable damping and oil-gas separation, comprising a shock absorber (1) and a resilient element (6); characterized in that: It also includes an accumulator (2) and a power module (3) used with the shock absorber (1); The inside of the shock absorber (1) is filled with oil; The side of the shock absorber (1) is provided with a hydraulic pipe joint (4); The shock absorber (1) is a double-cylinder electric control shock absorber, which comprises a liquid storage cylinder (13) and a working cylinder (14) arranged inside the liquid storage cylinder (13); The side of the liquid storage cylinder (13) is provided with an electromagnetic valve (12) connected with the ECU signal; The liquid inlet and outlet of the electromagnetic valve (12) are respectively connected with the inside cavity of the working cylinder (14) and the liquid storage cylinder (13); During operation, the current of the electromagnetic valve (12) is controlled by the ECU to adjust the opening of the electromagnetic valve (12) and adjust the damping force; The top of the liquid storage cylinder (13) is provided with a dynamic sealing assembly (15); The dynamic sealing assembly (15) comprises a lower guide (151), a middle guide (152) and an upper guide (153) which are sequentially sleeved outside the piston rod (11); The upper guide (153) is provided with a sealing ring between the inner wall of the liquid storage cylinder (13) and the piston rod (11), and a high-pressure oil seal (154) between the piston rod (11); The middle guide (152) is provided with a sealing ring between the inner wall of the liquid storage cylinder (13) and the piston rod (11), and two upper and lower stellite seals (155) between the piston rod (11); The lower guide (151) is sealingly connected with the top end of the working cylinder (14), and a guide bushing (156) is arranged between the lower guide (151) and the piston rod (11); The accumulator (2) comprises a shell (21), the inside of the shell (21) is separated into a gas chamber (201) and a liquid chamber (202) by a diaphragm (22); The gas chamber (201) is filled with high-pressure gas; The liquid chamber (202) is filled with oil; The power module (3) comprises a motor pump (31), an oil storage pot (32) and a switch valve (33); The accumulator (2) is connected with the hydraulic pipe joint (4) and the motor pump (31) through a three-way pipe (5); The switch valve (33) is arranged on the pipe between the motor pump (31) and the accumulator (2); The motor pump (31) and the switch valve (33) are respectively connected with the ECU signal; During operation, the motor pump (31) and the switch valve (33) are opened by the ECU control, and the oil in the oil storage pot (32) is pumped into the shock absorber (1) by the motor pump (31) to push the piston rod (11) of the shock absorber (1) to move outward to lift the vehicle body, or the oil in the shock absorber (1) is pumped out to retract the piston rod (11) inward to lower the vehicle body.

2. The oil and gas separating damper adjustable hydraulic active suspension system of claim 1, wherein: It also includes a height sensor arranged on the vehicle, which is used for monitoring the height of the vehicle body and transmitting signals to the ECU.

3. The oil and gas separating damper adjustable hydraulic active suspension system of claim 2, wherein: It also includes a speed sensor arranged on the vehicle, which is used for monitoring the driving speed of the vehicle and transmitting signals to the ECU.

4. The oil and gas separating damper adjustable hydraulic active suspension system of claim 1, wherein: The side of the liquid storage cylinder (13) is provided with a pipe sleeve (131); The hydraulic pipe joint (4) is fixed with the pipe sleeve (131) through threaded connection, and a sealing ring is arranged between the hydraulic pipe joint (4) and the pipe sleeve (131).

5. The oil and gas separating damper adjustable hydraulic active suspension system of claim 1, wherein: The outer side of the lower guide (151) and the inner wall of the liquid storage cylinder (13) are connected by a liquid flow channel (101).

6. The oil and gas separating damper adjustable hydraulic active suspension system, as recited in claim 5, c h a r a c t e r i z e d b y: The stuffing box (155) comprises a polytetrafluoroethylene ring and an O-ring sleeved outside the polytetrafluoroethylene ring; the polytetrafluoroethylene ring is in a stepped shape.

7. The oil and gas separating damper adjustable hydraulic active suspension system of claim 6, wherein: An end cover (157) is arranged above the upper guide (153), and the end cover (157) is fixed to the top end of the liquid storage cylinder (13) by threaded connection.

8. The oil and gas separating damper adjustable hydraulic active suspension system of claim 1, wherein: The high-pressure gas filled in the gas chamber (201) is high-pressure nitrogen.

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