Hydraulic suspension device, hydraulic suspension system having the same, and vehicle

Abstract

A hydraulic suspension device, a hydraulic suspension system (1000) having the same, and a vehicle are provided. The hydraulic suspension device includes a reservoir and a damper (200). The reservoir is provided on a vehicle body and stores oil. The damper (200) has a damper housing (201), a piston (202), and a piston rod (203). The damper housing (201) is connected to an axle. The piston (202) is located within the damper housing (201) and cooperates with the damper housing (201) to define an upper chamber (2011) and a lower chamber (2012). One end of the piston rod (203) is connected to the piston (202). The piston rod (203) is configured to be connected to the vehicle body. An oil passage (204) is provided within the piston rod (203). The oil passage (204) communicates with the lower chamber (2012) and the reservoir, thereby allowing oil to flow between the reservoir and the lower chamber (2012). The device and system can improve the driving stability of the vehicle without compromising the comfort of the vehicle.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application is based on and claims priority from a Chinese patent application filed on December 30, 2021, bearing application number 202111655945.3, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the field of vehicles, and more particularly to a hydraulic suspension device, a hydraulic suspension system having the same, and a vehicle. [Background technology]

[0003] A suspension is a device that transmits the interaction force between the body and the axle. It is one of the four main components of a vehicle and plays an important role in affecting the vehicle's driving performance. The suspension transmits the force and moment fed back from the road surface, damps wheel vibrations, cushions impacts, and improves the driver's driving experience, thereby enabling the vehicle to achieve ideal dynamic characteristics and driving stability. Related art suspensions often consist of springs, guide mechanisms, dampers, etc., but the damping coefficient of the damper and the stiffness of the spring are both constant, making it difficult to achieve both comfort and driving stability. Summary of the Invention [Problem to be solved by the invention]

[0004] The present application seeks to solve at least to some extent one of the technical problems in the related art.

[0005] Therefore, one object of the present application is to provide a hydraulic suspension device that can improve the driving stability of a vehicle without impairing the comfort of the vehicle.

[0006] The present application further provides a hydraulic suspension system having the above-described hydraulic suspension device.

[0007] The present application further provides a vehicle having the above hydraulic suspension system. [Means for solving the problem]

[0008] A hydraulic suspension device for adjusting the height of a vehicle body according to an embodiment of the present application includes a reservoir and a damper, wherein the reservoir is provided on the vehicle body and configured to store oil, the damper has a damper housing, a piston, and a piston rod, the damper housing is configured to be connected to an axle, the piston is located within the damper housing and cooperates with the damper housing to define an upper chamber and a lower chamber, one end of the piston rod is connected to the piston, and the piston rod is configured to be connected to the vehicle body, an oil passage is provided within the piston rod, and the oil passage communicates with the lower chamber and the reservoir, allowing oil to flow between the reservoir and the lower chamber.

[0009] The hydraulic suspension device according to the present invention stabilizes the connection of the oil circuit, avoids wear at the connection points due to vibration, and minimizes oil leakage at the connection points. Furthermore, the use of a hollow piston rod not only reduces weight, but also allows the position of the piston rod to be adjusted by utilizing the oil passage defined by the hollow piston rod to allow oil to flow in and out, resulting in a simple adjustment method, high reliability, low cost, and fast response. Furthermore, the ability to adjust the vehicle height improves vehicle handling stability without compromising vehicle comfort, effectively resolving the trade-off between vehicle comfort and handling stability.

[0010] In some embodiments of the present application, the reservoir includes a control pump and a tank, and the control pump is provided between the tank and the oil passage.

[0011] In some embodiments of the present application, an upper end of the piston rod extends from the damper housing, and an oil port that communicates the oil passage with the reservoir is formed at the upper end of the piston rod.

[0012] In some embodiments of the present application, the hydraulic suspension device further includes an oil discharge passage and an oil return passage, both of which communicate between the tank and the oil passage and partially overlap each other, and the control pump is provided in the oil discharge passage.

[0013] In some embodiments of the present application, the oil discharge passage includes a common passage and an oil discharge branch passage, the oil return passage includes the common passage and an oil return branch passage, one end of the common passage is connected to the oil passage, and the oil discharge branch passage and the oil return branch passage are both connected to the other end of the common passage.

[0014] In some embodiments of the present application, a check valve and the control pump are provided in the oil discharge branch path, one end of the check valve is connected to the common passage and the other end is connected to the control pump, and an oil return valve is provided in the oil return branch path.

[0015] In some embodiments of the present application, the hydraulic suspension device further includes an accumulator module, the oil passage communicating with the reservoir via a connecting passage, and the accumulator module communicating with the connecting passage and configured to adjust at least one of the damping and stiffness of the damper and the height of the vehicle body.

[0016] In some embodiments of the present application, the hydraulic suspension system further includes a first control valve, which is provided in the connecting passage and controls communication or cutoff between the reservoir and the accumulator module.

[0017] In some embodiments of the present application, the accumulator module includes a first accumulator and an opening adjustment valve, the first accumulator is connected to the connecting passage at a first connection point, and the opening adjustment valve is provided between the first connection point and the oil passage, and the opening adjustment valve adjusts the opening of the connecting passage between the oil passage and the first connection point to adjust the damping of the damper, and further adjusts the stiffness of the damper by closing the connecting passage between the oil passage and the first connection point.

[0018] In some embodiments of the present application, the accumulator module further includes a second accumulator and a stiffness adjustment valve, the connecting passage is provided with a second connection point that communicates with the second accumulator, and the stiffness adjustment valve is provided between the second accumulator and the second connection point and adjusts the stiffness of the damper by connecting or blocking communication between the connecting passage and the second accumulator.

[0019] In some embodiments of the present application, a second control valve is further provided between the second connection point and the oil passage.

[0020] In some embodiments of the present application, the accumulator module further includes a first accumulator and a second accumulator, the first accumulator communicating with the connecting passage at a first connection point, and the connecting passage having a second connection point communicating with the second accumulator.

[0021] Preferably, the first connection point is located between the oil passage and the second connection point.

[0022] Preferably, a second control valve is provided between the first connection point and the second connection point.

[0023] A hydraulic suspension system according to an embodiment of the present application includes a controller and a hydraulic suspension device according to any of the above embodiments of the present application, and the controller controls the direction of oil flow between the reservoir and the damper depending on the vehicle situation to increase or decrease the body height of the vehicle.

[0024] The hydraulic suspension system according to the present invention can adjust the height of the vehicle body, improving vehicle handling stability without compromising vehicle comfort, thereby effectively resolving the trade-off between vehicle comfort and handling stability. Furthermore, the use of a hollow piston rod not only reduces weight, but also allows the position of the piston rod to be adjusted by utilizing the oil passage defined by the hollow piston rod to allow oil to flow in and out, resulting in a simple adjustment method, high reliability, low cost, and fast response. Furthermore, the piston rod is provided with an oil passage communicating with the lower chamber, and the oil passage is connected to the reservoir, stabilizing the connection of the oil circuit and preventing wear and tear at the connection points due to vibration, thereby minimizing oil leakage at the connection points.

[0025] A vehicle according to an embodiment of the present application includes the hydraulic suspension system described in the above embodiment of the present application.

[0026] The vehicle according to the embodiment of the present application allows the height of the vehicle body to be adjusted, improving vehicle handling stability without compromising vehicle comfort, thereby effectively resolving the trade-off between vehicle comfort and handling stability. Furthermore, the use of a hollow piston rod not only reduces weight, but also allows the position of the piston rod to be adjusted by utilizing the oil passage defined by the hollow piston rod to allow oil to flow in or out, resulting in a simple adjustment method, high reliability, low cost, and fast response. Furthermore, the piston rod is provided with an oil passage communicating with the lower chamber, and the oil passage is connected to the reservoir, stabilizing the connection of the oil circuit and avoiding wear and tear at the connection points due to vibration, thereby minimizing oil leakage at the connection points.

[0027] Additional aspects and advantages of the present application will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the present application. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a schematic diagram of a hydraulic suspension system according to some embodiments of the present application. [Figure 2] FIG. 2 is a schematic diagram of a hydraulic suspension system according to some other embodiments of the present application. [Figure 3] 1 is a schematic diagram of a hydraulic suspension system according to some embodiments of the present application, the hydraulic suspension system having an anti-roll function. [Figure 4] FIG. 4 is a schematic diagram illustrating the hydraulic suspension system shown in FIG. 3 in a pressure increase mode. [Figure 5] FIG. 4 is a schematic diagram illustrating the hydraulic suspension system shown in FIG. 3 in lift mode. [Figure 6] FIG. 4 is a schematic diagram illustrating the hydraulic suspension system shown in FIG. 3 in a height reduction mode. [Figure 7] FIG. 4 is a schematic diagram illustrating the hydraulic suspension system shown in FIG. 3 in an anti-nose-dive braking mode and an anti-squat acceleration mode. [Figure 8] FIG. 4 is a schematic diagram illustrating the hydraulic suspension system shown in FIG. 3 in anti-roll mode. [Figure 9] 1 is a schematic diagram of a hydraulic suspension system having an anti-pitching mode according to some embodiments of the present application; [Figure 10] 1 is a schematic diagram of a hydraulic suspension system according to some other embodiments of the present application, the hydraulic suspension system having an anti-pitching mode. [Figure 11] FIG. 2 is a schematic diagram of a hydraulic suspension system according to some further embodiments of the present application. [Figure 12] FIG. 2 is a schematic diagram of a hydraulic suspension system according to some further embodiments of the present application. [Figure 13]FIG. 13 is a schematic diagram illustrating the hydraulic suspension system shown in FIG. 12 in a pressure increase mode. [Figure 14] FIG. 13 is a schematic diagram illustrating the hydraulic suspension system shown in FIG. 12 in lift mode. [Figure 15] FIG. 13 is a schematic diagram illustrating the hydraulic suspension system shown in FIG. 12 in height hold mode. [Figure 16] FIG. 13 is a schematic diagram of the hydraulic suspension system shown in FIG. 12 in height reduction mode. [Figure 17] FIG. 13 is a schematic diagram illustrating the hydraulic suspension system shown in FIG. 12 in anti-roll mode. [Figure 18] FIG. 13 is a schematic diagram illustrating the hydraulic suspension system shown in FIG. 12 in an anti-pitching mode. [Figure 19] 13 is a schematic diagram illustrating the hydraulic suspension system shown in FIG. 12 in anti-roll mode and height-hold mode. FIG. [Figure 20] 1 is a schematic diagram of a hydraulic suspension system according to another embodiment of the present application; [Figure 21] 1 is a schematic diagram of a hydraulic suspension system according to another embodiment of the present application; [Figure 22] 2 is a schematic diagram of a left front damper assembly and a right front damper assembly according to an embodiment of the present application. FIG. [Figure 23] FIG. 23 is a cross-sectional view of the damper assembly shown in FIG. 22. [Figure 24] FIG. 2 is a cross-sectional view of a central control cylinder according to an embodiment of the present application. [Figure 25] FIG. 2 is a perspective view of a central control cylinder according to an embodiment of the present application. [Figure 26] 1 is a schematic diagram of a metal bellows accumulator according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, the embodiments of the present application will be described in detail. Examples of the embodiments are shown in the drawings, and the same or similar reference numerals throughout indicate the same or similar parts or parts having the same or similar functions. The embodiments described below with reference to the drawings are merely illustrative and are intended to interpret the present application, but should not be understood as limiting the present application.

[0030] Hereinafter, a hydraulic suspension device according to an embodiment of the present application will be described with reference to FIGS. 1 to 26. The hydraulic suspension device is used in a vehicle, connects the axle of the vehicle to the body, and adjusts the height of the vehicle body.

[0031] 1 to 23 , a hydraulic suspension device according to an embodiment of the present application includes a reservoir and a damper 200. The reservoir is provided on a vehicle body and configured to store oil. The damper 200 has a damper housing 201, a piston 202, and a piston rod 203. The damper housing 201 is configured to be connected to an axle. The piston 202 is located within the damper housing 201 and cooperates with the damper housing 201 to define an upper chamber 2011 and a lower chamber 2012. One end of the piston rod 203 is connected to the piston 202. The piston rod 203 is configured to be connected to the vehicle body. An oil passage 204 is provided within the piston rod 203. The oil passage 204 communicates with the lower chamber 2012 and the reservoir, allowing oil to flow between the reservoir and the lower chamber 2012.

[0032] As can be seen, when a vehicle is traveling, the axle vibrates relative to the vehicle body, causing vibrations such as shaking. When a hydraulic suspension device according to an embodiment of the present application is installed on a vehicle, damper housing 201 is attached to the axle and piston rod 203 is connected to the vehicle body. As can be seen from this, the tip of piston rod 203 is stationary relative to the vehicle body, and damper housing 201 can move relative to piston rod 203 together with the axle. Because oil passage 204 of piston rod 203 is connected to the reservoir via the oil circuit, the impact of axle vibration on the connection points of the oil circuit can be reduced, the connection of the oil circuit can be stabilized, wear at the connection points between the oil circuit and the reservoir can be reduced, and wear at the connection points between the oil circuit and piston rod 203 can be reduced.

[0033] As can also be understood, oil in the reservoir can enter the lower chamber 2012 through the oil passage 204, and when the piston rod 203 moves downward and the volume in the lower chamber 2012 becomes smaller, the oil in the lower chamber 2012 can also flow into the reservoir through the oil passage 204.

[0034] Specifically, the hydraulic suspension device has a lift mode and a height reduction mode. In the lift mode, oil in the reservoir can enter the oil passage 204, and the hydraulic oil that has entered the oil passage 204 flows into the lower chamber 2012, thereby increasing the hydraulic pressure in the lower chamber 2012 and moving the piston 202 upward, which in turn moves the piston rod 203 upward, thereby achieving the purpose of lifting the vehicle body.

[0035] In the height reduction mode, the oil in the reservoir no longer enters the oil passage, and the oil in the damper 200 can flow out of the oil passage 204 due to the gravity of the vehicle, causing the oil pressure in the lower chamber 2012 of the damper 200 to decrease, causing the piston 202 to move downward, which in turn causes the piston rod 203 to move downward, thereby moving the vehicle body downward and achieving the purpose of reducing the height of the vehicle body.

[0036] When a vehicle is traveling, it will encounter various road conditions, and once the vehicle suspension system in the related art is selected, it cannot be adjusted while the vehicle is traveling. Therefore, the conventional suspension can only ensure that the vehicle achieves optimal matching of performance under specific road and speed conditions, and passively receives the ground force acting on the vehicle body, and cannot change suspension parameters according to the road and vehicle speed, and furthermore, cannot actively control the ground force acting on the vehicle body.

[0037] The hydraulic suspension system according to the embodiment of the present application can adjust the height of the vehicle body according to road conditions, etc. For example, when traveling on a steep mountain road, the system can enter a lift mode to raise the center of gravity of the vehicle and improve the stability of the vehicle. When it is necessary to reduce the impact of the vehicle body on the traveling speed, the system can enter a height reduction mode to lower the center of gravity of the vehicle. Of course, it should be understood that the above is merely an illustrative example, and the height of the vehicle body may be adjusted according to actual needs during traveling.

[0038] In the hydraulic suspension device according to the embodiment of the present application, the piston rod 203 is provided with an oil passage 204 communicating with the lower chamber 2012, and the oil passage 204 is connected to a reservoir, thereby stabilizing the connection of the oil circuit, avoiding wear at the connection due to vibration, and minimizing oil leakage at the connection. Furthermore, the use of a hollow piston rod 203 not only reduces weight, but also allows the position of the piston rod 203 to be adjusted by utilizing the oil passage 204 defined by the hollow piston rod 203 to allow oil to flow in and out, resulting in a simple adjustment method, high reliability, low cost, and fast response. Furthermore, the ability to adjust the vehicle height improves vehicle handling stability without compromising vehicle comfort, effectively resolving the trade-off between vehicle comfort and handling stability.

[0039] 1 to 23, in some embodiments of the present application, the upper end of piston rod 203 extends from damper housing 201, and an oil port that communicates oil passage 204 with the reservoir is formed at the upper end of piston rod 203. Thus, by providing the oil port at the upper end of piston rod 203, it becomes easier to connect the oil circuit and the oil port, and installation efficiency is improved.

[0040] 1 to 21 , in some embodiments of the present application, the reservoir includes a control pump 26 and a tank 1, and the control pump 26 is provided between the tank 1 and the oil passage 204. Specifically, oil is stored in the tank 1, and the control pump 26 can send the oil in the tank 1 to the oil passage 204. Therefore, by providing the control pump 26, the mounting position of the tank 1 is not limited, and the tank 1 can be positioned rationally according to the space available in the vehicle.

[0041] Preferably, the hydraulic suspension system further includes an oil discharge passage and an oil return passage, both of which communicate with and partially overlap the tank 1 and the oil passage 204, with the control pump 26 provided in the oil discharge passage. That is, oil in the tank 1 flows into the oil passage 204 through the oil discharge passage, and oil in the oil passage 204 flows into the tank 1 through the oil return passage. By providing the oil discharge passage and the oil return passage, oil discharge and oil return can be achieved independently, ensuring reliable progress of the oil discharge and oil return. Furthermore, because the oil discharge passage and the oil return passage partially overlap, the number of connecting pipes can be reduced, allowing the hydraulic suspension system to be made more compact.

[0042] In some specific examples of the present application, as shown in FIGS. 1 to 21 , the oil discharge passage includes a common passage 33 and an oil discharge branch passage 34, and the oil return passage includes a common passage 33 and an oil return branch passage 35. One end of the common passage 33 is connected to an oil passage 204, and both the oil discharge branch passage 34 and the oil return branch passage 35 are connected to the other end of the common passage 33. That is, the common passage 33 is the portion where the oil discharge passage and the oil return passage overlap, the oil discharge branch passage 34 is connected to the oil outlet of the tank 1, the oil return branch passage 35 is connected to the oil inlet of the tank 1, and the control pump 26 is provided in the oil discharge branch passage 34. As a result, oil in the tank 1 can flow into the oil passage 204 through the oil discharge branch passage 34 and the common passage 33. Oil in the oil passage 204 can flow into the tank 1 through the common passage 33 and the oil return branch passage 35. This ensures the reliability of oil return and oil discharge.

[0043] Preferably, as shown in FIGS. 1 to 21 , a check valve 28 and a control pump 26 are provided in the oil discharge branch passage 34, one end of the check valve 28 is connected to the common passage 33 and the other end is connected to the control pump 26, and an oil return valve 27 is provided in the oil return branch passage 35. Specifically, the tank 1 has independent oil return and discharge passages. When oil needs to be discharged, the control pump 26 is turned on and the oil return valve 27 is closed, and the control pump 26 guides oil to the oil passage 204 of the damper 200. When oil needs to be returned, the control pump 26 is turned off and the oil return valve 27 is opened, allowing oil flowing out of the oil passage 204 of the damper 200 to flow through the oil return valve 27 to the tank 1. When returning oil, the check valve 28 effectively prevents oil from flowing into the control pump 26, thereby preventing oil from flowing through the control pump 26 to the oil outlet in the event of an unexpected malfunction of the control pump 26. This ensures reliable oil discharge and return.

[0044] 1 to 21 , in some examples of the present application, the controlled pump 26 includes a control valve element 260 and a drive motor 261, and the drive motor 261 is electrically connected to a valve in the control valve element 260, and the drive motor 261 rotates to control the rotation of the valve, thereby turning on or off the controlled pump 26. As a result, the control pump 26 is turned on or off by cooperation between the drive motor 261 and the valve, ensuring reliable operation of the controlled pump 26 and reducing the influence of oil on turning on or off the controlled pump 26.

[0045] In some embodiments of the present application, as shown in Figures 1 to 12, the hydraulic suspension system further includes a relief valve 31, which is located at the outlet end of the control pump 26. When the pressure at the oil outlet of the control pump 26 reaches a certain threshold, the relief valve 31 opens to relieve pressure, thereby ensuring that the hydraulic suspension system remains within a normal pressure range. Note that the operating principle of the relief valve 31 is a conventional technology and will not be described in detail here.

[0046] In some embodiments of the present application, as shown in FIGS. 1 to 21 , the hydraulic suspension device further includes a pressure stabilizing accumulator 29, which is provided at the outlet end of the control pump 26, so as to stabilize the pressure and eliminate flow rate fluctuations at the outlet end of the control pump 26.

[0047] In some examples of the present application, the pressure-stabilizing accumulator 29 may be a metal bellows accumulator. As shown in FIG. 26, the metal bellows accumulator consists of a cylindrical body assembly and a bellows assembly. The cylindrical body assembly includes an upper cover, a packing, a cylinder tube, a snap ring, and a seal ring, while the bellows assembly includes a seal cap, a guide ring, a bellows, and a lower cover. The metal bellows accumulator may use a metal bellows 101 as a flexible separator between the fluid and the gas, instead of an air bag or a diaphragm. The bellows can be used over a very wide temperature range. The metal bellows is welded to other components, making it completely airtight. It can move up and down inside the accumulator without friction or wear, allowing it to operate for a long time with just one adjustment.

[0048] In some embodiments of the present application, the hydraulic suspension system further includes an accumulator module, wherein the oil passage 204 is in communication with the reservoir through a connecting passage, and the accumulator module is in communication with the connecting passage and is configured to adjust at least one of the damping and stiffness of the damper 200 and the body height of the vehicle. Note that the accumulator module serves as an accumulator, i.e., oil can flow into the accumulator module to be accumulated, and the oil in the accumulator module can be discharged to replenish when needed by the hydraulic suspension system.

[0049] Specifically, when the accumulator module adjusts the height of the vehicle body, oil in the accumulator module can flow into the oil passage 204 and enter the lower chamber 2012, or oil in the lower chamber 2012 can flow into the accumulator module for accumulation. When the accumulator module adjusts the damping of the damper 200, the flow path of the connecting passage narrows or widens to adjust the damping (i.e., the flow resistance of the oil entering and leaving the damper 200 increases or decreases). When the accumulator module adjusts the stiffness of the damper 200, the connecting passage can be selectively connected to the accumulator module, or the accumulator module can be selectively disconnected from the connecting passage. This increases the adjustability of the hydraulic suspension system, thereby improving the running stability of a vehicle equipped with the hydraulic suspension system.

[0050] As shown in FIGS. 1 to 21 , in some embodiments of the present application, the hydraulic suspension system further includes a first control valve 3. The first control valve 3 is provided in the connecting passage and controls communication between the reservoir and the accumulator module. That is, when the first control valve 3 blocks the connecting passage, the flow path between the reservoir and the accumulator module is blocked, and oil in the reservoir does not flow into the accumulator module. Therefore, the provision of the first control valve 3 makes it possible to determine whether accumulation in the accumulator module is necessary, and if accumulation is necessary, the first control valve 3 is opened. After accumulation is completed, the first control valve 3 is closed, and the accumulator module is used to adjust at least one of the damping and stiffness of the damper 200 and the vehicle body height.

[0051] As shown in FIGS. 1 to 21 , in some embodiments of the present application, the accumulator module includes a first accumulator 9 and an opening adjustment valve 8, the first accumulator 9 communicates with a connecting passage at a first connection point, and the opening adjustment valve 8 is provided between the first connection point and an oil passage 204, and the opening adjustment valve 8 adjusts the opening of the connecting passage between the oil passage 204 and the first connection point to adjust the damping of the damper 200, and further adjusts the rigidity of the damper 200 by closing the connecting passage between the oil passage 204 and the first connection point.

[0052] Specifically, the first accumulator 9 can accumulate oil. When the opening adjustment valve 8 is open, the opening of the opening adjustment valve 8 narrows, reducing the amount of oil flowing through the connecting passage. This narrows the flow path from the damper 200 to the connecting passage, thereby increasing damping. When the opening adjustment valve 8 widens, the flow path from the damper 200 to the connecting passage widens, reducing damping. Therefore, the cooperation of the first accumulator 9 and the opening adjustment valve 8 ensures reliable damping adjustment of the hydraulic suspension system and ensures that the amount of oil flowing through the connecting passage meets the required damping. In other words, the opening adjustment valve 8 adjusts the flow rate of oil in the corresponding connecting passage, thereby achieving the goal of adjusting the damping of the hydraulic suspension system. This allows the damping of the hydraulic suspension system 1000 to be adjusted according to actual conditions, such as road conditions, ensuring that the damping of the hydraulic suspension system 1000 meets vibration control requirements and effectively resolving the tradeoff between vehicle comfort and handling stability.

[0053] When the opening adjustment valve 8 is in the closed state, the connection between the damper 200 and the first accumulator 9 is cut off, and the oil in the damper 200 cannot flow into the first accumulator 9, and the oil in the first accumulator 9 cannot flow into the damper 200, thereby improving the rigidity of the damper 200. In this case, the opening adjustment valve 8 is a shutoff adjustment valve, and can not only adjust the opening, but also shut off and connect.

[0054] In some examples of the present application, the opening adjustment valve 8 includes a first motor and a first valve body, and the first motor controls the operation of the valve in the first valve body to change the flow area of ​​the first valve body, thereby achieving the purpose of flow rate adjustment.

[0055] In some embodiments of the present application, the accumulator module further includes a second accumulator 10 and a stiffness adjustment valve 11. The connecting passage is provided with a second connection point that communicates with the second accumulator 10. The stiffness adjustment valve 11 is provided between the second accumulator 10 and the second connection point and adjusts the stiffness of the damper 200 by connecting or blocking the communication between the connecting passage and the second accumulator 10. Specifically, when the stiffness adjustment valve 11 is opened, oil can flow between the second accumulator 10 and the damper 200. When the stiffness adjustment valve 11 is closed, the connection between the second accumulator 10 and the damper 200 is blocked, preventing oil from inside the damper 200 from flowing into the second accumulator 10 and preventing oil from inside the second accumulator 10 from flowing into the damper 200. This improves the stiffness of the damper 200.

[0056] 1 to 9, a second control valve 12 is preferably further provided between the second connection point and the oil passage 204. As a result, when the second control valve 12 is closed and the stiffness adjustment valve 11 is opened, the oil in the tank 1 can enter and accumulate in the second accumulator 10. Thus, by providing the second control valve 12, the second accumulator 10 can be used for accumulation.

[0057] 1 to 21, the accumulator module further includes a first accumulator 9 and a second accumulator 10. The first accumulator 9 communicates with a connecting passage at a first connection point, and the connecting passage is provided with a second connection point that communicates with the second accumulator 10. Specifically, by providing the first accumulator 9 and the second accumulator 10, the rigidity of the connecting passage can be adjusted using the first accumulator 9 and the second accumulator 10. Preferably, the first connection point is located between the oil passage 204 and the second connection point.

[0058] In some specific examples of the present application, a second control valve 12 is provided between the first connection point and the second connection point, so that the number of accumulators communicating with the damper 200 can be controlled by opening and closing the second control valve 12, thereby adjusting the stiffness or damping of the damper 200.

[0059] Hereinafter, a hydraulic suspension system 1000 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 26. The hydraulic suspension system 1000 is used in a vehicle and connects an axle of the vehicle to a body.

[0060] A hydraulic suspension system according to an embodiment of the present application includes a controller and a hydraulic suspension device according to any of the above embodiments of the present application, and the controller controls the direction of oil flow between the reservoir and the damper depending on the vehicle situation to increase or decrease the body height of the vehicle.

[0061] The hydraulic suspension system 1000 according to the embodiment of the present application includes a plurality of damper assemblies 2.

[0062] The multiple damper assemblies 2 are divided into a left front damper assembly 2, a left rear damper assembly 2, a right front damper assembly 2, and a right rear damper assembly 2, and each set of damper assemblies 2 includes a damper 200. In the description of this application, "front" refers to the direction toward the head of the vehicle, and "rear" refers to the direction toward the tail of the vehicle, and in the forward direction, the direction to the right of the main driver is the right side, and the direction to the left of the main driver is the left side.

[0063] The oil passages 204 of each set of damper assemblies 2 are connected to a reservoir via a connecting passage. The oil in the reservoir flows into each oil passage 204 to move the piston 202 upward, and the piston 202 moves the piston rod 203 and the vehicle body upward. In the height reduction mode, the oil in each lower chamber 2012 flows into the reservoir through the oil passage 204 to move the piston 202 downward, and the piston 202 moves the piston rod 203 and the vehicle body downward.

[0064] Specifically, hydraulic suspension system 1000 has a lift mode and a height reduction mode, and a controller controls hydraulic suspension system 1000 to switch between the lift mode and the height reduction mode according to the situation of the vehicle. In the lift mode, oil can enter oil passage 204 of left front damper assembly 2, oil passage 204 of right front damper assembly 2, oil passage 204 of left rear damper assembly 2, and oil passage 204 of right rear damper assembly 2, and the hydraulic oil that has entered each oil passage 204 flows into lower chamber 2012, thereby increasing the hydraulic pressure in lower chamber 2012 and moving piston 202 upward, which in turn moves piston rod 203 upward. The piston rod 203 of the left front damper assembly 2 moves up, the piston rod 203 of the right front damper assembly 2 moves up, the piston rod 203 of the left rear damper assembly 2 moves up, and the piston rod 203 of the right rear damper assembly 2 moves up, thereby moving the vehicle body up and achieving the purpose of lifting the vehicle body.

[0065] In the height reduction mode, gravity allows oil to flow out of the oil passages 204 of the left front damper assembly 2, the right front damper assembly 2, the left rear damper assembly 2, and the right rear damper assembly 2, respectively, reducing the oil pressure in the lower chamber 2012 of each damper 200, causing the pistons 202 to move downward, which in turn moves the piston rods 203 downward. The piston rods 203 of the left front damper assembly 2, the right front damper assembly 2, the left rear damper assembly 2, and the right rear damper assembly 2 move downward, causing the vehicle body to move downward, thereby achieving the purpose of reducing the vehicle height.

[0066] When a vehicle is traveling, it will encounter various road conditions, and once the vehicle suspension system in the related art is selected, it cannot be adjusted while the vehicle is traveling. Therefore, the conventional suspension can only ensure that the vehicle achieves optimal matching of performance under specific road and speed conditions, and passively receives the ground force acting on the vehicle body, and cannot change suspension parameters according to the road and vehicle speed, and furthermore, cannot actively control the ground force acting on the vehicle body.

[0067] The hydraulic suspension system 1000 according to the embodiment of the present application can adjust the height of the vehicle body according to road conditions, etc. For example, when traveling on a steep mountain road, the system can enter a lift mode to raise the center of gravity of the vehicle and improve the stability of the vehicle. When it is necessary to reduce the impact of the vehicle body on the traveling speed, the system can enter a height reduction mode to lower the center of gravity of the vehicle. Of course, it should be understood that the above is merely an exemplary description, and the height of the vehicle body may be adjusted according to actual needs during traveling.

[0068] The hydraulic suspension system 1000 according to the embodiment of the present application can adjust the height of the vehicle body, improving vehicle handling stability without compromising vehicle comfort, and effectively resolving the trade-off between vehicle comfort and handling stability. Furthermore, the use of a hollow piston rod 203 not only reduces weight, but also allows the position of the piston rod 203 to be adjusted by utilizing an oil passage 204 defined by the hollow piston rod 203 to allow oil to flow in and out, resulting in a simple adjustment method, high reliability, low cost, and fast response. Furthermore, the piston rod 203 is provided with an oil passage 204 communicating with the lower chamber 2012, and the oil passage 204 is connected to a reservoir, thereby stabilizing the connection of the oil circuit, preventing wear at the connection points due to vibration, and minimizing oil leakage at the connection points.

[0069] In some specific examples of the present application, each connecting passage is provided with a first control valve 3 for opening or closing the connecting passage, i.e., when the first control valve 3 corresponding to each set of damper assemblies 2 closes the corresponding connecting passage, the flow path between the tank 1 and the oil passage 204 of the corresponding damper assembly 2 is blocked, and oil in the tank 1 does not flow into the corresponding damper 200, and oil in the damper 200 does not flow into the tank 1.

[0070] As shown in Figures 10 and 12 to 21, in some embodiments of the present application, the hydraulic suspension system 1000 further includes a first height maintenance branch path and a second height maintenance branch path, the first height maintenance branch path being connected to the oil passage 204 of the left front damper assembly 2 and the oil passage 204 of the right front damper assembly 2, respectively, and the first height maintenance branch path being provided with a first height control valve 6 for connecting or disconnecting the first height maintenance branch path.

[0071] The second height maintaining branch path is connected to the oil passage 204 of the left rear damper assembly 2 and the oil passage 204 of the right rear damper assembly 2, respectively, and the second height maintaining branch path is provided with a second height control valve 7 for opening or closing the path.

[0072] Specifically, when the first height control valve 6 is opened, the first height maintenance branch is open, and when the first height control valve 6 is closed, the first height maintenance branch is closed. When the second height control valve 7 is opened, the second height maintenance branch is open, and when the second height control valve 7 is closed, the second height maintenance branch is closed.

[0073] When it is necessary to maintain the height of the vehicle body, the hydraulic suspension system 1000 can be switched to a height maintenance mode, in which the first height control valve 6 and the second height control valve 7 are both opened, the first height maintenance branch path and the second height maintenance branch path are connected, the oil passage 204 of the left front damper assembly 2 communicates with the oil passage 204 of the right front damper assembly 2, and the oil passage 204 of the left rear damper assembly 2 communicates with the oil passage 204 of the right front damper assembly 2. right The piston rod 203 of the left front damper assembly 2 and the piston rod 203 of the right front damper assembly 2 are in an interlocking state, and the piston rod 203 of the left rear damper assembly 2 and right The piston rod 203 of the rear damper assembly 2 is in an interlocking state, which allows the vehicle body to maintain its current height as much as possible.

[0074] In some embodiments of the present application, as shown in FIGS. 1 to 12 , the accumulator module includes a second accumulator 10, and each set of damper assemblies 2 is provided with one corresponding second accumulator 10. The second accumulator 10 is connected to a connecting passage, and a stiffness adjustment valve 11 is provided at the oil inlet / outlet of the second accumulator 10. The first control valve 3 is located between the second accumulator 10 and the tank 1. Specifically, when the first control valve 3 and the stiffness adjustment valve 11 are opened, oil in the tank 1 can enter and accumulate in the second accumulator 10. When the first control valve 3 is closed and the stiffness adjustment valve 11 is opened, oil in each second accumulator 10 can flow into the oil passage 204 in the corresponding damper assembly 2, thereby lifting the piston rod 203. That is, the second accumulator 10 can also adjust the height of the vehicle body. When stiffness needs to be increased, the first control valve 3 is closed and the stiffness adjustment valve 11 is closed, thereby isolating the second accumulator 10 from the corresponding damper 200 and increasing the stiffness of the suspension.

[0075] As can be appreciated, each stiffness adjustment valve 11 can be adjusted independently, thereby allowing the front and rear stiffness of the hydraulic suspension system 1000 to be matched to meet the needs of different modes. For example, in the vehicle's anti-nose dive mode and anti-roll mode during cornering, the front axles need to provide greater stiffness, so the stiffness adjustment valves 11 corresponding to the left front damper assembly 2 and the right front damper assembly 2 can be closed, and the stiffness adjustment valves 11 corresponding to the right rear damper assembly 2 and the left rear damper assembly 2 can be opened.

[0076] In some examples of the present application, the first accumulator 9 is a metal bellows accumulator, and the second accumulator 10 is a diaphragm accumulator, which has a faster pressure accumulation capability and a larger pressure accumulation volume than the metal bellows accumulator. Since the diaphragm accumulator can accumulate a larger pressure amount in a shorter time, the second accumulator 10 uses a diaphragm accumulator to accumulate pressure in each suspension to realize vehicle body lift. Note that the accumulation principles of the metal bellows accumulator and the diaphragm accumulator are both conventional technologies and will not be described in detail here.

[0077] 1 to 9, the connecting passage is provided with a second control valve 12 for connecting or disconnecting the connecting passage, and the second control valve 12 is located between the second accumulator 10 and the oil passage 204. Specifically, the hydraulic suspension system 1000 can have a pressure-increasing mode, and as shown in FIG. 4, in the pressure-increasing mode, the first control valve 3 is opened, the second control valve 12 is closed, the stiffness adjustment valve 11 is opened, and the oil in the tank 1 enters and accumulates in the second accumulator 10.

[0078] When it is necessary to switch to lift mode, the first control valve 3 is closed, the second control valve 12 is opened, the stiffness adjustment valve 11 is opened, and the oil in the second accumulator 10 enters the oil passage 204 to lift the piston 202.

[0079] When it is necessary to switch to the height reduction mode, the first control valve 3 is opened, the second control valve 12 is opened, and the stiffness adjustment valve 11 is opened, and the oil flowing out from the oil passage 204 of the damper 200 returns to the tank 1. As a result, by providing the second control valve 12, it is possible to accumulate oil first using the stiffness adjustment valve 11, and when lift or stiffness adjustment is necessary, it can be achieved by opening and closing the stiffness adjustment valve 11, which has a fast response speed and is reliable.

[0080] Preferably, the hydraulic suspension system 1000 may further have an anti-nose-dive braking mode and an anti-squat acceleration mode, and while the vehicle is running, the first control valve 3 corresponding to each set of damper assemblies 2 can be controlled to close, the second control valve 12 to open, and the stiffness adjustment valve 11 to close, so that the oil passage 204 of each set of damper assemblies 2 communicates with the first accumulator 9, and the first accumulator 9 can adjust the amount of oil in the corresponding damper 200. Therefore, the damper 200 corresponding to each set of damper assemblies 2 has a reaction force against the movement tendency of the vehicle body at the corresponding position, and the hydraulic suspension system 1000 has an anti-nose-dive braking mode and an anti-squat acceleration mode.

[0081] As shown in Figures 2, 10, 12 to 19, and 21, in some embodiments of the present application, the accumulator module includes a central accumulator 13, and the first control valves 3 corresponding to each set of damper assemblies 2 are connected to the central accumulator 13. That is, when the first control valves 3 are closed, the oil in the tank 1 enters and accumulates in the central accumulator 13. When the first control valves 3 are opened, the oil in the central accumulator 13 can flow into the oil passages 204 of each set of damper assemblies 2. Therefore, the provision of the central accumulator 13 allows the oil to be accumulated first by increasing the pressure, ensuring that the oil can flow reliably to each set of damper assemblies 2 and achieving a rapid response.

[0082] As shown in Figures 3 to 8, in some embodiments of the present application, the upper chamber 2011 of the left front damper assembly 2 is connected to the lower chamber 2012 of the right front damper assembly 2 via a first pipeline, and the lower chamber 2012 of the left front damper assembly 2 is connected to the upper chamber 2011 of the right front damper assembly 2 via a second pipeline.

[0083] The upper chamber 2011 of the left rear damper assembly 2 is connected to the lower chamber 2012 of the right rear damper assembly 2 via a third pipe line, and the lower chamber 2012 of the left rear damper assembly 2 is connected to the upper chamber 2011 of the right rear damper assembly 2 via a fourth pipe line.

[0084] Specifically, when the vehicle tends to roll, that is, when the hydraulic suspension system 1000 is in a state where one side is compressed and the other side is pulled, for example, when the left front damper assembly 2 and the left rear damper assembly 2 are compressed and the right front damper assembly 2 and the right rear damper assembly 2 are pulled, the oil in the lower chamber 2012 of the left front damper assembly 2 passes through the second pipe line and enters the upper chamber 2011 of the right front damper assembly 2, causing the piston rod 203 of the right front damper assembly 2 to descend.

[0085] The oil in the lower chamber 2012 of the left rear damper assembly 2 passes through the fourth conduit into the upper chamber 2011 of the right rear damper assembly 2, causing the piston rod 203 of the right rear damper assembly 2 to descend, which in turn causes the piston rod 203 of the right front damper assembly 2 to descend, thereby providing a downward force to the right side of the vehicle body, thereby allowing the hydraulic suspension system 1000 to provide an anti-roll moment and prevent the vehicle from continuing to roll. Of course, it should be understood that the above description of the oil flow paths is merely an exemplary explanation to introduce the anti-roll principle, and that when the right side is compressed and the left side is pulled, the hydraulic suspension system 1000 can provide an anti-roll force using the above anti-roll principle.

[0086] 3 to 8, the first and third pipes communicate with each other to form a first circuit, and the second and fourth pipes communicate with each other to form a second circuit. The hydraulic suspension system 1000 further includes a first adjustable accumulator 14 and a second adjustable accumulator 15. The first adjustable accumulator 14 is connected to the first circuit and a first adjustable valve 18 is provided at an oil inlet and outlet of the first adjustable accumulator 14. The second adjustable accumulator 15 is connected to the second circuit and a second adjustable valve 19 is provided at an oil inlet and outlet of the second adjustable accumulator 15.

[0087] Specifically, by forming the first and second circuits, it is possible to achieve linked adjustment of the right front damper assembly 2, the left front damper assembly 2, and the left rear damper assembly 2, and it is possible to achieve linked adjustment of the right rear damper assembly 2, the left front damper assembly 2, and the left rear damper assembly 2, and it is also possible to provide an anti-roll moment to ensure that the vehicle does not continue to roll. The rigidity of the hydraulic suspension system 1000 can be adjusted by controlling the opening and closing states of the first and second adjusting valves 18 and 19. For example, closing the first and second adjusting valves 18 and 19 can improve the rigidity of the hydraulic suspension system 1000. Specifically, the first and second adjusting accumulators 14 and 15 can be diaphragm-type accumulators.

[0088] As shown in Figures 9 to 19, in some embodiments of the present application, the upper chamber 2011 of the left front damper assembly 2 is connected to the lower chamber 2012 of the left rear damper assembly 2 via a fifth pipeline, and the lower chamber 2012 of the left front damper assembly 2 is connected to the upper chamber 2011 of the left rear damper assembly 2 via a sixth pipeline.

[0089] The upper chamber 2011 of the right front damper assembly 2 is connected to the lower chamber 2012 of the right rear damper assembly 2 via the seventh pipe line, and the lower chamber 2012 of the right front damper assembly 2 is connected to the upper chamber 2011 of the right rear damper assembly 2 via the eighth pipe line.

[0090] Specifically, when the vehicle tends to pitch, that is, when one of the front and rear sides of the hydraulic suspension system 1000 is compressed and the other is pulled, for example, when the piston rod 203 of the left front damper assembly 2 and the piston rod 203 of the right front damper assembly 2 are compressed, oil in the lower chamber of the left front damper assembly 2 flows through the sixth pipe line into the upper chamber 2011 of the left rear damper assembly 2, causing the piston rod 203 of the left rear damper assembly 2 to descend, thereby aligning the front and rear and achieving anti-pitching.

[0091] The oil in the lower chamber 2012 of the right front damper assembly 2 flows through the eighth pipe into the upper chamber 2011 of the right rear damper assembly 2, lowering the piston rod 203 of the right rear damper assembly 2. This allows the hydraulic suspension system 1000 to provide an anti-pitching force to prevent the vehicle from continuing to pitch.

[0092] Of course, it will be understood that the above oil flow path description is merely an exemplary explanation to introduce the anti-pitching principle, and by utilizing the above anti-pitching principle, when the rear side is compressed and the front side is pulled, the hydraulic suspension system 1000 can provide an anti-pitching force.

[0093] Preferably, as shown in Figures 9 to 19, the fifth pipe line communicates with the seventh pipe line via the first connecting pipe line to form a third circuit, and the sixth pipe line communicates with the eighth pipe line via the second connecting pipe line to form a fourth circuit. The hydraulic suspension system 1000 further includes a third adjustable accumulator 16 and a fourth adjustable accumulator 17. The third adjustable accumulator 16 is connected to the third circuit, and a third adjustable valve 20 is provided at an oil inlet and outlet of the third adjustable accumulator 16. The fourth adjustable accumulator 17 is connected to the fourth circuit, and a fourth adjustable valve 21 is provided at an oil inlet and outlet of the fourth adjustable accumulator 17. Specifically, the third adjustable accumulator 16 and the fourth adjustable accumulator 17 can be diaphragm-type accumulators.

[0094] As can be seen from this, by forming the third and fourth circuits, it is possible to achieve linked adjustment of the right front damper assembly 2, the right rear damper assembly 2, the left front damper assembly 2, and the left rear damper assembly 2. Anti This ensures that a pitching moment is provided to prevent the vehicle from continuing to pitch. By controlling the open / close states of the third adjusting valve 20 and the fourth adjusting valve 21, the rigidity of the hydraulic suspension system 1000 can be adjusted. For example, closing the third adjusting valve 20 and the fourth adjusting valve 21 can improve the rigidity of the hydraulic suspension system 1000.

[0095] 9 and 10, the first connecting pipe is provided with a first on-off valve 22 for connecting or disconnecting the first connecting pipe, and the second connecting pipe is provided with a second on-off valve 23 for connecting or disconnecting the second connecting pipe. That is, when the first on-off valve 22 is closed, the communication between the fifth pipe and the seventh pipe is cut off, and when the second on-off valve 23 is closed, the communication between the sixth pipe and the eighth pipe is cut off. This makes it possible to determine whether the four damper assemblies 2 need to be linked according to actual demand.

[0096] As shown in FIGS. 11 to 21, 24, and 25, in some embodiments of the present application, the hydraulic suspension system 1000 further includes a central control cylinder 24, which includes a second cylinder 240 and a moving member 241. The moving member 241 is movably disposed within the second cylinder 240 and cooperates with the second cylinder 240 to control a first chamber 243, a second chamber 244, a third chamber 245, and a fourth chamber 246. The first chamber 243, the second chamber 244, the third chamber 245 and the fourth chamber 246 are arranged in order in the moving direction of the movable member 241, the first chamber 243 and the second chamber 244 are located on one side of the intermediate contact portion 2411 of the movable member 241, and the third chamber 245 and the fourth chamber 246 are located on the other side of the intermediate contact portion 2411, and the intermediate contact portion 2411 is movably engaged with the inner wall of the second cylinder 240.

[0097] The oil passage 204 of the left front damper assembly 2 is connected to one of the first chamber 243 and the second chamber 244, and the oil passage 204 of the right rear damper assembly 2 is connected to the other of the first chamber 243 and the second chamber 244. The oil passage 204 of the left rear damper assembly 2 is connected to one of the third chamber 245 and the fourth chamber 246, and the oil passage 204 of the right front damper assembly 2 is connected to the other of the third chamber 245 and the fourth chamber 246. For convenience of explanation, the principle will be explained below using as an example a case where the oil passage 204 of the left front damper assembly 2 is connected to the first chamber 243, the oil passage 204 of the right rear damper assembly 2 is connected to the second chamber 244, the oil passage 204 of the left rear damper assembly 2 is connected to the third chamber 245, and the oil passage 204 of the right front damper assembly 2 is connected to the fourth chamber 246.

[0098] Specifically, when the vehicle tends to roll, for example, when the piston rods 203 of the left front damper assembly 2 and the left rear damper assembly 2 are compressed and the piston rods 203 of the right front damper assembly 2 and the right rear damper assembly 2 are pulled, the oil in the lower chamber 2012 of the left front damper assembly 2 flows into the first chamber 243 through the oil passage 204, and the oil in the lower chamber 2012 of the left rear damper assembly 2 flows into the third chamber 245 through the oil passage 204, and the oil in the first chamber 243 flows into the third chamber 245 through the oil passage 204. Since the first chamber 243 and the third chamber 245 are located on both sides of the intermediate contact portion 2411, the direction of the force of the oil in the first chamber 243 acting on the intermediate contact portion 2411 is opposite to the direction of the force of the third chamber 245 acting on the intermediate contact portion 2411, and the two opposite acting forces cancel each other out, so that the moving member 241 does not move, thereby suppressing the movement of the piston rod 203 of the left front damper assembly 2 and the piston rod 203 of the left rear damper assembly 2, and thereby playing a role in suppressing roll.

[0099] If the left front wheel encounters an obstacle, the left front wheel will lift up, and as the vehicle continues to travel, the center of gravity of the vehicle will rise, and there is a risk that the right front wheel and left rear wheel will leave the ground, causing the vehicle to become uncontrollable. When the left front wheel of the vehicle encounters an obstacle such as a stone, the left front wheel lifts up and the compression width of the left front damper assembly 2 becomes greater than the compression width of the left rear damper assembly 2. In this case, the amount of oil flowing from the left front damper assembly 2 into the first chamber 243 becomes greater than the amount of oil flowing from the left rear damper assembly 2 into the third chamber 245, causing the moving member 241 to move to the right and press the third chamber 245 and the fourth chamber 246. The oil in the third chamber 245 flows into the lower chamber 2012 of the left rear damper assembly 2 and moves the piston rod 203 upward, and the oil in the fourth chamber 246 flows into the lower chamber 2012 of the right front damper assembly 2 and moves the piston rod 203 upward, thereby reducing the possibility of the left rear wheel and right front wheel leaving the ground and improving the stability of the vehicle.

[0100] Of course, it is understood that the above several situations are merely illustrative, and when the vehicle encounters other modes such as right front wheel lift, left rear wheel lift, etc., the oil will flow according to the above interlocking principle to prevent the vehicle from rolling, and each mode will not be described in detail here.

[0101] 24 , in some embodiments of the present application, the moving member 241 includes a moving body portion 2410, the middle contact portion 2411 is an annular protrusion provided on the moving body portion 2410, and a middle cavity, a left cavity, and a right cavity are provided in the second cylinder 240 in the moving direction of the moving member 241, and the inlets of the left cavity and the right cavity are located on the inner wall of the middle cavity. The left end of the moving body portion 2410 is inserted into the left cavity through the inlet of the left cavity, and the right end of the moving body portion 2410 is inserted into the right cavity through the inlet of the right cavity.

[0102] A first chamber 243 is defined between the left end of the moving body portion 2410 and the left cavity, a part of the moving body portion 2410 and the inner wall of the left cavity are slidably engaged, a middle contact portion 2411 and the inner wall of the middle cavity are slidably engaged to define a second chamber 244 and a third chamber 245, and a fourth chamber 246 is defined between the right end of the moving body portion 2410 and the right cavity, thereby simplifying the structure of the central control cylinder 24.

[0103] 24 , the central control cylinder 24 preferably further includes a first return spring 247 and a second return spring 248. Both ends of the first return spring 247 abut against the left ends of the second cylinder 240 and the moving member 241, respectively. Both ends of the second return spring 248 abut against the right ends of the second cylinder 240 and the moving member 241, respectively. The first return spring 247 and the second return spring 248 push the moving member 241 to return it toward the center. Specifically, when the vehicle rolls and moves the moving member 241 to the left, the first return spring 247 can push the moving member 241 to the right, thereby returning the moving member 241. When the vehicle rolls and moves the moving member 241 to the right, the second return spring 248 can push the moving member 241 to the left, thereby returning the moving member 241. This ensures the reliability of the central control cylinder 24.

[0104] In some examples of the present application, as shown in FIG. 24 , the central control cylinder 24 includes a guide assembly 249, the guide assembly includes a first guide member 2490 and a second guide member 2491, the first guide member 2490 and the second guide member 2491 are slidably engaged with each other, the first guide member 2490 is fixed to the second cylinder 240, the second guide member 2491 is fixed to the moving member 241, the first return spring 247 is fitted on the left guide assembly 249, and the first guide member 2490, and the second return spring 248 is fitted onto the outside of the right guide assembly 249 and abuts against the first guide member 2490. Thus, by providing the guide assembly 249, not only can the first return spring 247 and the second return spring 248 be easily assembled, but the degree of deformation of the first return spring 247 and the second return spring 248 can also be easily limited, and failures caused by excessive deformation of the first return spring 247 and the second return spring 248 can be avoided.

[0105] Preferably, the second guide member 2491 is a screw, and one end of the second guide member 2491 enters into the first guide member 2490 and movably engages with the first guide member 2490, thereby making the structure of the guide assembly 249 simple and reliable.

[0106] As shown in FIG. 25, the ports connected to the piston rods 203 of the four damper assemblies 2 of the central control cylinder 24 are located on the same side, which makes it easy to connect the pipes.

[0107] 1 to 23, in some embodiments of the present application, each set of damper assemblies 2 includes a vibration damping spring 205, and both ends of the vibration damping spring 205 are configured to be connected to the vehicle body and the axle. Thus, by providing the vibration damping spring 205, the cushioning effect of each set of damper assemblies 2 can be improved, and vibration of the vehicle body while the vehicle is running can be reduced.

[0108] Preferably, as shown in Figures 1 to 23, the vibration damping spring 205 of the left front damper assembly 2 is fitted and fixed to the outside of the damper 200, the vibration damping spring 205 of the right front damper assembly 2 is fitted and fixed to the outside of the damper 200, the vibration damping spring 205 of the left rear damper assembly 2 is arranged in parallel with the damper 200, and the vibration damping spring 205 of the right rear damper assembly 2 is arranged in parallel with the damper 200.

[0109] Hereinafter, with reference to Figures 1 to 21, the hydraulic suspension system 1000 according to several specific embodiments of the present application will be described in detail. To facilitate understanding, the above embodiments are merely illustrative and not restrictive, and each embodiment can be modified exemplarily according to actual circumstances. [Example]

[0110] 1 , a hydraulic suspension system 1000 according to an embodiment of the present application includes a left front damper assembly 2, a right front damper assembly 2, a left rear damper assembly 2, a right rear damper assembly 2, an accumulator module, a tank 1, a control pump 26, an oil return valve 27, a check valve 28, a pressure stabilizing accumulator 29, a relief valve 31, and an opening adjustment valve 8. The accumulator module includes a first accumulator 9, a second accumulator 10, and a pressure-reducing accumulator 30.

[0111] The left front damper assembly 2 and the right front damper assembly 2 both include a damper 200 and a vibration damping spring 205, and the vibration damping spring 205 is fitted and fixed to the outside of the damper 200. The left rear damper assembly 2 and the right rear damper assembly 2 both include a damper 200 and a vibration damping spring 205, and the vibration damping spring 205 is provided in parallel with the damper 200, and both ends of the vibration damping spring 205 of the left rear damper assembly 2 are connected to the vehicle body and the axle, respectively. Both ends of the vibration damping spring 205 of the right rear damper assembly 2 are connected to the vehicle body and the axle, respectively. Each damper 200 includes a damper housing 201, a piston rod 203, and a piston 202, the piston rod 203 is connected to the piston 202, the piston 202 is movably disposed within the damper housing 201 to define an upper chamber 2011 and a lower chamber 2012, an oil passage 204 is provided within the piston rod 203, the oil passage 204 is connected to the lower chamber 2012, the oil passage 204 of each damper assembly 2 is connected to the tank 1 via a connecting passage, and a first control valve 3 is provided in each connecting passage.

[0112] The tank 1 has an oil outlet and an oil inlet. A control pump 26 is connected to the oil outlet and the connecting passage, respectively, to guide the oil in the tank 1 to the connecting passage. An oil return valve 27 is connected to the oil inlet and the connecting passage, respectively, and when the oil return valve 27 is opened, oil flows from the connecting passage to the oil inlet. A check valve 28 is provided at the outlet end of the control pump 26 and is unidirectional. A pressure stabilizing accumulator 29 is provided at the outlet end of the control pump 26 and is located between the check valve 28 and the control pump 26. The pressure stabilizing accumulator 29 can stabilize the pressure and eliminate flow rate fluctuations at the outlet end of the control pump 26.

[0113] The hydraulic suspension system 1000 includes a common flow path and four branch flow paths, and the four branch flow paths are respectively connected to the oil passages 204 of the four damper assemblies 2. The check valve 28 and the oil return valve 27 are each connected to the common flow path. The relief valve 31 is also connected to the common flow path.

[0114] The first control valve 3 corresponding to each damper assembly 2 is connected in series to the corresponding branch flow path, and the first control valve 3 controls the conduction or blocking of the branch flow path.

[0115] The second accumulator 10 corresponding to each damper assembly 2 is connected to the corresponding branch flow path, and a stiffness adjustment valve 11 is provided at the oil inlet / outlet of the second accumulator 10, and the stiffness adjustment valve 11 is normally closed.

[0116] Each branch flow path is further provided with an opening adjustment valve 8, a first accumulator 9, and a second control valve 12. The opening adjustment valve 8 adjusts the flow rate through the corresponding branch flow path to adjust the damping of the hydraulic suspension system 1000. The first accumulator 9 is capable of accumulating. The second control valve 12 is provided between the first accumulator 9 and the second accumulator 10.

[0117] One pressure-reducing accumulator 30 is provided corresponding to each damper assembly 2, and the pressure-reducing accumulator 30 corresponding to the left front damper assembly 2 is directly connected to the piston rod 203 and communicates with the corresponding oil passage 204, and the pressure-reducing accumulator 30 corresponding to the right front damper assembly 2 is directly connected to the piston rod 203 and communicates with the corresponding oil passage 204. The pressure-reducing accumulator 30 corresponding to the left rear damper assembly 2 is connected to the corresponding branch passage, and the pressure-reducing accumulator 30 corresponding to the right rear damper assembly 2 is directly connected to the corresponding branch passage.

[0118] Specifically, the hydraulic suspension system 1000 has a pressure increase mode, a lift mode, and a height decrease mode, and in the pressure increase mode, the first control valve 3 is opened, the second control valve 12 is closed, the stiffness adjustment valve 11 is opened, and the control pump 26 is operated, so that the oil in the tank 1 flows through four branch flow paths into the corresponding second accumulators 10 and is accumulated. After the oil has been accumulated using the second accumulators 10, the stiffness adjustment valves 11 are closed.

[0119] In the lift mode, the oil in the tank 1 or the oil in the accumulator module can enter the oil passage 204 of the left front damper assembly 2, the oil passage 204 of the right front damper assembly 2, the oil passage 204 of the left rear damper assembly 2, and the oil passage 204 of the right rear damper assembly 2. The hydraulic oil that enters each oil passage 204 flows into the lower chamber 2012, thereby increasing the hydraulic pressure in the lower chamber 2012 and moving the piston 202 upward, which in turn moves the piston rod 203 upward. The piston rod 203 of the left front damper assembly 2 moves upward, the piston rod 203 of the right front damper assembly 2 moves upward, the piston rod 203 of the left rear damper assembly 2 moves upward, and the piston rod 203 of the right rear damper assembly 2 moves upward, causing the vehicle body to move upward, thereby achieving the purpose of lifting the vehicle body.

[0120] In the height reduction mode, oil can flow out of the oil passages 204 of the left front damper assembly 2, the right front damper assembly 2, the left rear damper assembly 2, and the right rear damper assembly 2, respectively, reducing the oil pressure in the lower chamber 2012 of each damper 200, causing the pistons 202 to move downward, which in turn moves the piston rods 203 downward. The piston rods 203 of the left front damper assembly 2, the right front damper assembly 2, the left rear damper assembly 2, and the right rear damper assembly 2 move downward, causing the vehicle body to move downward, thereby achieving the purpose of reducing the vehicle height. As can be seen, in height reduction mode, oil flowing out of each set of damper assemblies 2 may flow directly into the tank 1, may flow into the accumulator assembly for accumulation, or may flow into both the tank 1 and the accumulator assembly.

[0121] When the pressure in the hydraulic suspension system 1000 is high, for example, when it is detected that the pressure at the outlet of the control pump 26 reaches a certain threshold (30 MPa), the oil return valve 27 opens to relieve pressure and protect the hydraulic suspension system 1000 within the normal pressure range, and at this time, the oil in each damper 200 can flow into the oil tank 1 through the connecting passage and the oil return valve 27.

[0122] After relief, if the pressure in the hydraulic suspension system 1000 is still high or the pressure is high during operation, the relief valve 31 can be opened to relieve the pressure, thereby ensuring reliable operation of the entire hydraulic suspension system 1000.

[0123] If the damping of the hydraulic suspension system 1000 is too great while the vehicle is running, the vehicle body will shake, affecting comfort, so the amount of oil in each branch passage can be adjusted by the opening adjustment valve 8 to adjust the damping of the hydraulic suspension system 1000. When the opening of the opening adjustment valve 8 is reduced to reduce the amount of oil that can flow through the connecting passage, damping increases. When the opening of the opening adjustment valve 8 is increased, damping decreases.

[0124] If the rigidity of the hydraulic suspension system 1000 is too high and reduces the comfort of the vehicle, the rigidity adjustment valve 11 can be controlled to open, allowing the oil in the second accumulator 10 to replenish into each branch flow path, thereby reducing the rigidity of the hydraulic suspension system 1000 and improving the damping effect of the hydraulic suspension system 1000 against vibrations.

[0125] When the vehicle is shaken or impacted while traveling, the oil in the lower chamber 2012 of each damper assembly 2 passes through the oil passage 204 and enters the pressure-reducing accumulator 30 for accumulation, thereby achieving the goal of quickly reducing pressure. Since the front axle of the vehicle must ensure driving stability and the rear axle of the vehicle must primarily ensure comfort, the pressure-reducing accumulator 30 corresponding to the left front damper assembly 2 is directly connected to the piston rod 203 and communicates with the corresponding oil passage 204, and the pressure-reducing accumulator 30 corresponding to the right front damper assembly 2 is directly connected to the piston rod 203 and communicates with the corresponding oil passage 204, thereby achieving rapid relief. The pressure-reducing accumulator 30 for the rear axle may also be located between the first accumulator 9 and the second accumulator 10, so that oil flows out of the damper 200 to provide damping and then relief, thereby improving comfort. [Example]

[0126] 2, compared to the first embodiment, the hydraulic suspension system 1000 according to this embodiment further includes a central accumulator 13 and a central pressure-accumulator regulation valve 32, and the central pressure-accumulator regulation valve 32 is connected to the oil inlet / outlet of the central accumulator 13, and the central pressure-accumulator regulation valve 32 is connected to a common flow path. Note that in this embodiment, the same structure and mode as those in the first embodiment will not be described in detail.

[0127] In the pressure-increasing mode, the central pressure-accumulation regulating valve 32 is opened, the stiffness regulating valve 11 is opened, and oil flowing out from the tank 1 flows into the central accumulator 13 and the second accumulator 10 and accumulates there.

[0128] In the lift mode, the central accumulator regulating valve 32 is opened, the stiffness regulating valve 11 is closed, and oil flowing out from the central accumulator 13 flows into the lower chamber 2012 of each damper assembly 2, raising the piston rod 203 and lifting the vehicle body.

[0129] In height reduction mode, oil exiting each damper assembly 2 can flow into the central accumulator 13 and / or tank 1 . [Example]

[0130] As shown in FIGS. 3 to 8, compared to the first embodiment, the hydraulic suspension system 1000 according to the embodiment of the present invention further includes an anti-roll mode.

[0131] As shown in Figures 3 to 8, the upper chamber 2011 of the left front damper assembly 2 is connected to the lower chamber 2012 of the right front damper assembly 2 via a first pipe line, and the lower chamber 2012 of the left front damper assembly 2 is connected to the upper chamber 2011 of the right front damper assembly 2 via a second pipe line.

[0132] The upper chamber 2011 of the left rear damper assembly 2 communicates with the lower chamber 2012 of the right rear damper assembly 2 via a third pipe line, and the lower chamber 2012 of the left rear damper assembly 2 communicates with the upper chamber 2011 of the right rear damper assembly 2 via a fourth pipe line. The first pipe line and the third pipe line communicate to form a first circuit, and the second pipe line and the fourth pipe line communicate to form a second circuit. The hydraulic suspension system 1000 further includes a first adjustable accumulator 14 and a second adjustable accumulator 15. The first adjustable accumulator 14 is connected to the first circuit and a first adjustable valve 18 is provided at an oil inlet and outlet of the first adjustable accumulator 14. The second adjustable accumulator 15 is connected to the second circuit and a second adjustable valve 19 is provided at an oil inlet and outlet of the second adjustable accumulator 15.

[0133] Specifically, as shown in FIG. 8, when the vehicle tends to roll, that is, when the hydraulic suspension system 1000 is in a state where one side is compressed and the other side is pulled, for example, when the left front damper assembly 2 and the left rear damper assembly 2 are compressed and the right front damper assembly 2 and the right rear damper assembly 2 are pulled, the oil in the lower chamber 2012 of the left front damper assembly 2 and the oil in the lower chamber 2012 of the left rear damper assembly 2 enters the upper chamber 2011 of the right front damper assembly 2 through the second circuit.

[0134] The oil in the lower chamber 2012 of the left rear damper assembly 2 and the oil in the lower chamber 2012 of the left front damper assembly 2 pass through the second circuit and enter the upper chamber 2011 of the right rear damper assembly 2, causing the piston rod 203 of the right front damper assembly 2 to descend, which in turn applies a downward force to the right side of the vehicle body, allowing the vehicle to align left and right, thereby allowing the hydraulic suspension system 1000 to provide an anti-roll moment to prevent the vehicle from continuing to roll. Of course, it should be understood that the above description of the oil flow paths is merely an illustrative example to introduce the anti-roll principle, and that when the right side is compressed and the left side is pulled, the hydraulic suspension system 1000 can provide an anti-roll force using the above anti-roll principle.

[0135] As shown in FIG. 4, the first control valve 3 is opened, the second control valve 12 is closed, and the stiffness adjustment valve 11 is opened, and each second accumulator 10 is used for accumulation.

[0136] As shown in FIG. 5, in the lift mode, the first control valve 3 is closed, the second control valve 12 is opened, and the stiffness adjustment valve 11 is opened, allowing the oil in the second accumulator 10 to enter the oil passage 204 of the corresponding damper 200 to realize lift.

[0137] As shown in FIG. 6, in the height reduction mode, the first control valve 3 is opened, the second control valve 12 is opened, the stiffness adjustment valve 11 is closed, and the piston rod 203 of each damper 200 moves downward, causing the oil in the lower chamber 2012 to flow into the branch flow paths through the oil passage 204, and the oil in the four branch flow paths is collected in a common flow path and then flows into the tank 1 through the oil return valve 27.

[0138] As shown in FIG. 7 , when the first control valve 3 is closed, the second control valve 12 is open, and the stiffness adjustment valve 11 is closed, the oil in the first accumulator 9 and the pressure-reducing accumulator 30 flows into the oil passage 204, or the oil in the oil passage 204 flows into the first accumulator 9 or the pressure-reducing accumulator 30 and accumulates. As can be seen, when the vehicle is starting, the rear of the vehicle tends to sink and the front of the vehicle tends to lift due to inertial force. Since the upper chamber 2011 of the left front damper assembly 2 and the lower chamber 2012 of the right front damper assembly 2 are connected, the piston rods 203 of the left front damper assembly 2 and the piston rods 203 of the right front damper assembly 2 are held stationary, thereby suppressing the tendency for the front of the vehicle to lift and providing an anti-squat function. Similarly, during vehicle braking, the piston rods 203 of the left front damper assembly 2 and the right front damper assembly 2 are held stationary. [Example]

[0139] As shown in FIG. 9, compared with the first embodiment, in this embodiment, the hydraulic suspension system 1000 according to the embodiment of the present application further has an anti-pitching mode.

[0140] The upper chamber 2011 of the left front damper assembly 2 is connected to the lower chamber 2012 of the left rear damper assembly 2 via a fifth pipeline, and the lower chamber 2012 of the left front damper assembly 2 is connected to the upper chamber 2011 of the left rear damper assembly 2 via a sixth pipeline.

[0141] The upper chamber 2011 of the right front damper assembly 2 communicates with the lower chamber 2012 of the right rear damper assembly 2 via a seventh pipe, and the lower chamber 2012 of the right front damper assembly 2 communicates with the upper chamber 2011 of the right rear damper assembly 2 via an eighth pipe. The fifth pipe communicates with the seventh pipe via a first connecting pipe to form a third circuit, and the sixth pipe communicates with the eighth pipe via a second connecting pipe to form a fourth circuit. The hydraulic suspension system 1000 further includes a third adjustable accumulator 16 and a fourth adjustable accumulator 17. The third adjustable accumulator 16 is connected to the third circuit, and a third adjustable valve 20 is provided at an oil inlet and outlet of the third adjustable accumulator 16. The fourth adjustable accumulator 17 is connected to the fourth circuit, and a fourth adjustable valve 21 is provided at an oil inlet and outlet of the fourth adjustable accumulator 17. The first connecting pipe line is provided with a first on-off valve 22 for connecting or blocking the first connecting pipe line, and the second connecting pipe line is provided with a second on-off valve 23 for connecting or blocking the second connecting pipe line.

[0142] Specifically, when the vehicle tends to pitch, that is, when one of the front and rear sides of the hydraulic suspension system 1000 is compressed and the other is pulled, for example, when the piston rod 203 of the left front damper assembly 2 and the piston rod 203 of the right front damper assembly 2 are compressed, the oil in the lower chamber 2012 of the left front damper assembly 2 flows through the sixth pipe line into the upper chamber 2011 of the left rear damper assembly 2, causing the piston rod 203 of the left rear damper assembly 2 to descend.

[0143] The oil in the lower chamber 2012 of the right front damper assembly 2 flows through the eighth pipe into the upper chamber 2011 of the right rear damper assembly 2, lowering the piston rod 203 of the right front damper assembly 2. This allows the hydraulic suspension system 1000 to provide an anti-pitching force to prevent the vehicle from continuing to pitch.

[0144] By forming the third and fourth circuits, it is possible to achieve linked adjustment of the right front damper assembly 2, the right rear damper assembly 2, the left front damper assembly 2, and the left rear damper assembly 2, and further to provide an anti-pitching moment to ensure that the vehicle does not continue to pitch. The rigidity of the hydraulic suspension system 1000 can be adjusted by controlling the opening and closing states of the third adjusting valve 20 and the fourth adjusting valve 21. For example, closing the third adjusting valve 20 and the fourth adjusting valve 21 can improve the rigidity of the hydraulic suspension system 1000.

[0145] When the first on-off valve 22 is closed, the communication between the fifth and seventh lines is cut off, and when the second on-off valve 23 is closed, the communication between the sixth and eighth lines is cut off, thereby making it possible to determine whether the four sets of damper assemblies 2 need to be linked together according to actual demand.

[0146] Of course, it will be understood that the above oil flow path description is merely an exemplary explanation to introduce the anti-pitching principle, and by utilizing the above anti-pitching principle, when the rear side is compressed and the front side is pulled, the hydraulic suspension system 1000 can provide an anti-pitching force. [Example]

[0147] As shown in FIG. 10 , compared to the fourth embodiment, the hydraulic suspension system 1000 according to the present embodiment does not include a second accumulator 10, and further includes a central accumulator 13, a first height maintenance branch path, and a second height maintenance branch path, the first height maintenance branch path being connected to the oil passage 204 of the left front damper assembly 2 and the oil passage 204 of the right front damper assembly 2, respectively, and the first height maintenance branch path being provided with a first height control valve 6 for connecting or disconnecting the first height maintenance branch path.

[0148] The second height maintaining branch path is connected to the oil passage 204 of the left rear damper assembly 2 and the oil passage 204 of the right rear damper assembly 2, respectively, and the second height maintaining branch path is provided with a second height control valve 7 for opening or closing the path.

[0149] Specifically, when the first height control valve 6 is opened, the first height maintenance branch is open, and when the first height control valve 6 is closed, the first height maintenance branch is closed. When the second height control valve 7 is opened, the second height maintenance branch is open, and when the second height control valve 7 is closed, the second height maintenance branch is closed.

[0150] When it is necessary to maintain the height of the vehicle body, hydraulic suspension system 1000 can be switched to height maintenance mode, in which first height control valve 6 and second height control valve 7 are both opened, the first height maintenance branch path and the second height maintenance branch path are connected, the oil passage 204 of the left front damper assembly 2 is connected to the oil passage 204 of the right front damper assembly 2, and the oil passage 204 of the left rear damper assembly 2 is connected to the oil passage 204 of the right rear damper assembly 2. That is, the piston rod 203 of the left front damper assembly 2 is in an interlocking state with the piston rod 203 of the right front damper assembly 2, and the piston rod 203 of the left rear damper assembly 2 is in an interlocking state with the piston rod 203 of the right rear damper assembly 2, thereby enabling the vehicle body to maintain its current height as much as possible.

[0151] In the height maintenance mode, the first control valve 3 and the second control valve 12 are controlled to be in a closed state.

[0152] In this embodiment, in the pressure increase mode, the first control valve 3 is closed, and the oil in the tank 1 flows into the central accumulator 13 and accumulates there. [Example]

[0153] As shown in FIG. 11, in this embodiment, compared with the fourth embodiment, the hydraulic suspension system 1000 according to the embodiment of the present application further includes a central control cylinder 24 .

[0154] The central control cylinder 24 includes a second cylinder 240 and a movable member 241. The movable member 241 is movably disposed within the second cylinder 240 and cooperates with the second cylinder 240 to define a first chamber 243, a second chamber 244, a third chamber 245 and a fourth chamber 246. The first chamber 243, the second chamber 244, the third chamber 245 and the fourth chamber 246 are arranged in order in the moving direction of the movable member 241. The first chamber 243 and the second chamber 244 are located on one side of an intermediate contact portion 2411 of the movable member 241, and the third chamber 245 and the fourth chamber 246 are located on the other side of the intermediate contact portion 2411. The intermediate contact portion 2411 movably engages with the inner wall of the second cylinder 240.

[0155] The oil passage 204 of the left front damper assembly 2 is connected to one of the first chamber 243 and the second chamber 244, and the oil passage 204 of the right rear damper assembly 2 is connected to the other of the first chamber 243 and the second chamber 244. The oil passage 204 of the left rear damper assembly 2 is connected to one of the third chamber 245 and the fourth chamber 246, and the oil passage 204 of the right front damper assembly 2 is connected to the other of the third chamber 245 and the fourth chamber 246. For convenience of explanation, the principle will be explained below using as an example a case where the oil passage 204 of the left front damper assembly 2 is connected to the first chamber 243, the oil passage 204 of the right rear damper assembly 2 is connected to the second chamber 244, the oil passage 204 of the left rear damper assembly 2 is connected to the third chamber 245, and the oil passage 204 of the right front damper assembly 2 is connected to the fourth chamber 246.

[0156] Specifically, when the vehicle tends to roll, for example, when the piston rods 203 of the left front damper assembly 2 and the left rear damper assembly 2 are compressed and the piston rods 203 of the right front damper assembly 2 and the right rear damper assembly 2 are pulled, the oil in the lower chamber 2012 of the left front damper assembly 2 flows into the first chamber 243 through the oil passage 204, and the oil in the lower chamber 2012 of the left rear damper assembly 2 flows into the third chamber 245 through the oil passage 204, and the oil in the first chamber 243 flows into the third chamber 245 through the oil passage 204. Since the first chamber 243 and the third chamber 245 are located on both sides of the intermediate contact portion 2411, the direction of the force of the oil in the first chamber 243 acting on the intermediate contact portion 2411 is opposite to the direction of the force of the third chamber 245 acting on the intermediate contact portion 2411, and the two opposite acting forces cancel each other out, so that the moving member 241 does not move, thereby suppressing the movement of the piston rod 203 of the left front damper assembly 2 and the piston rod 203 of the left rear damper assembly 2, and thereby playing a role in suppressing roll.

[0157] When the left front wheel of the vehicle encounters an obstacle such as a stone, the left front wheel lifts up and the compression width of the left front damper assembly 2 becomes greater than the compression width of the left rear damper assembly 2. In this case, the amount of oil flowing from the left front damper assembly 2 into the first chamber 243 becomes greater than the amount of oil flowing from the left rear damper assembly 2 into the third chamber 245, causing the moving member 241 to move to the right and press the third chamber 245 and the fourth chamber 246. The oil in the third chamber 245 flows into the lower chamber 2012 of the left rear damper assembly 2 and moves the piston rod 203 upward, and the oil in the fourth chamber 246 flows into the lower chamber 2012 of the right front damper assembly 2 and moves the piston rod 203 upward, thereby reducing the possibility of the left rear wheel and right front wheel leaving the ground and improving the stability of the vehicle. Of course, it is understood that the above several situations are merely illustrative, and when the vehicle encounters other modes such as right front wheel lift, left rear wheel lift, etc., the oil will flow according to the above interlocking principle to prevent the vehicle from rolling, and each mode will not be described in detail here.

[0158] As can be understood, the hydraulic suspension system 1000 of this embodiment also has the anti-pitching mode described in the fourth embodiment, so the description thereof will be omitted here. [Example]

[0159] As shown in Figures 12 to 19, in this embodiment, compared to Example 4, the hydraulic suspension system 1000 according to the embodiment of the present application does not have the second accumulator 10, and the hydraulic suspension system 1000 according to the embodiment of the present application is provided with a central accumulator 13, a central control cylinder 24, a first height maintenance branch path and a second height maintenance branch path.

[0160] A central pressure-accumulation regulating valve 32 is connected to the oil inlet and outlet of the central accumulator 13, and the central pressure-accumulation regulating valve 32 is connected to the common flow path.

[0161] The central control cylinder 24 includes a second cylinder 240 and a movable member 241. The movable member 241 is movably disposed within the second cylinder 240 and cooperates with the second cylinder 240 to define a first chamber 243, a second chamber 244, a third chamber 245 and a fourth chamber 246. The first chamber 243, the second chamber 244, the third chamber 245 and the fourth chamber 246 are arranged in order in the moving direction of the movable member 241. The first chamber 243 and the second chamber 244 are located on one side of an intermediate contact portion 2411 of the movable member 241, and the third chamber 245 and the fourth chamber 246 are located on the other side of the intermediate contact portion 2411. The intermediate contact portion 2411 movably engages with the inner wall of the second cylinder 240.

[0162] The oil passage 204 of the left front damper assembly 2 is connected to one of the first chamber 243 and the second chamber 244, and the oil passage 204 of the right rear damper assembly 2 is connected to the other of the first chamber 243 and the second chamber 244. The oil passage 204 of the left rear damper assembly 2 is connected to one of the third chamber 245 and the fourth chamber 246, and the oil passage 204 of the right front damper assembly 2 is connected to the other of the third chamber 245 and the fourth chamber 246.

[0163] The first height maintaining branch path is connected to the oil passage 204 of the left front damper assembly 2 and the oil passage 204 of the right front damper assembly 2, and the first height maintaining branch path is provided with a first height control valve 6 for opening or closing the path.

[0164] The second height maintaining branch path is connected to the oil passage 204 of the left rear damper assembly 2 and the oil passage 204 of the right rear damper assembly 2, respectively, and the second height maintaining branch path is provided with a second height control valve 7 for opening or closing the path.

[0165] Specifically, for ease of explanation, the principle will be explained using an example in which the oil passage 204 of the left front damper assembly 2 is connected to the first chamber 243, the oil passage 204 of the right rear damper assembly 2 is connected to the second chamber 244, the oil passage 204 of the left rear damper assembly 2 is connected to the third chamber 245, and the oil passage 204 of the right front damper assembly 2 is connected to the fourth chamber 246.

[0166] Specifically, as shown in FIG. 13, the hydraulic suspension system 1000 enters pressure boost mode, the central pressure accumulation adjustment valve 32 is opened, the four first control valves 3 are closed, the first height control valve 6 is closed, the second height control valve 7 is closed, and the oil flowing out of the tank 1 flows into the central accumulator 13 and is accumulated.

[0167] As shown in FIG. 14, when the vehicle enters lift mode, the central accumulator regulating valve 32 is opened, the four first control valves 3 are opened, the first height control valve 6 is closed, and the second height control valve 7 is closed.

[0168] The oil flowing out from the central accumulator 13 passes through four branch flow paths and enters the oil passages 204 of the four damper assemblies 2, respectively, and the oil in the oil passages 204 enters the lower chamber 2012, moving the piston rod 203 upward and lifting the vehicle body.

[0169] 15, when it is necessary to maintain the height of the vehicle body, hydraulic suspension system 1000 can be switched to height maintenance mode, in which first height control valve 6 and second height control valve 7 are all opened, four first control valves 3 are closed, the first height maintenance branch path and the second height maintenance branch path are connected, oil passage 204 of left front damper assembly 2 communicates with oil passage 204 of right front damper assembly 2, and oil passage 204 of left rear damper assembly 2 communicates with oil passage 204 of right rear damper assembly 2. That is, piston rod 203 of left front damper assembly 2 and piston rod 203 of right front damper assembly 2 are interlocked, and piston rod 203 of left rear damper assembly 2 and piston rod 203 of right rear damper assembly 2 are interlocked, thereby enabling the vehicle body to maintain its current height as much as possible.

[0170] As shown in FIG. 16, when the vehicle enters the height reduction mode, the central pressure accumulation regulating valve 32 is closed, the four first control valves 3 are opened, the first height control valve 6 is closed, and the second height control valve 7 is closed.

[0171] The oil flowing out of the lower chamber 2012 of each damper assembly 2 returns to the tank 1 through the connecting passage and the oil return valve 27, thereby moving each piston rod 203 downward and reducing the height of the vehicle body.

[0172] As shown in FIG. 17, the central pressure-accumulation adjustment valve 32 is closed, the first height adjustment valve 6 is closed, the second height adjustment valve 7 is closed, and the four first control valves 3 are closed.

[0173] When the vehicle tends to roll, for example, when the piston rods 203 of the left front damper assembly 2 and the left rear damper assembly 2 are compressed and the piston rods 203 of the right front damper assembly 2 and the right rear damper assembly 2 are pulled, the oil in the lower chamber 2012 of the left front damper assembly 2 flows through the oil passage 204 into the first chamber 243, and the oil in the lower chamber 2012 of the left rear damper assembly 2 flows through the oil passage 204 into the third chamber 245, and the oil in the first chamber 24 Since the third chamber 245 is located on both sides of the intermediate contact portion 2411, the direction of the force of the oil in the first chamber 243 acting on the intermediate contact portion 2411 is opposite to the direction of the force of the third chamber 245 acting on the intermediate contact portion 2411, and the two opposite acting forces cancel each other out, so that the moving member 241 does not move, thereby suppressing the movement of the piston rod 203 of the left front damper assembly 2 and the piston rod 203 of the left rear damper assembly 2, and thereby playing a role in suppressing roll.

[0174] When the left front wheel of the vehicle encounters an obstacle such as a stone, the left front wheel lifts up and the compression width of the left front damper assembly 2 becomes greater than the compression width of the left rear damper assembly 2. In this case, the amount of oil flowing from the left front damper assembly 2 into the first chamber 243 becomes greater than the amount of oil flowing from the left rear damper assembly 2 into the third chamber 245, causing the moving member 241 to move to the right and press the third chamber 245 and the fourth chamber 246. The oil in the third chamber 245 flows into the lower chamber 2012 of the left rear damper assembly 2 and moves the piston rod 203 upward, and the oil in the fourth chamber 246 flows into the lower chamber 2012 of the right front damper assembly 2 and moves the piston rod 203 upward, thereby reducing the possibility of the left rear wheel and right front wheel leaving the ground and improving the stability of the vehicle.

[0175] Of course, it is understood that the above several situations are merely illustrative, and when the vehicle encounters other modes such as right front wheel lift, left rear wheel lift, etc., the oil will flow according to the above interlocking principle to prevent the vehicle from rolling, and each mode will not be described in detail here.

[0176] As shown in FIG. 18, the third regulating valve 20 is opened, the fourth regulating valve 21 is opened, the central pressure accumulation regulating valve 32 is closed, the first height regulating valve 6 is closed, the second height regulating valve 7 is closed, the four first control valves 3 are closed, the first opening / closing valve 22 is opened, and the second opening / closing valve 23 is opened.

[0177] When the vehicle tends to pitch, that is, when one of the front and rear sides of the hydraulic suspension system 1000 is compressed and the other is pulled, for example, when the piston rod 203 of the left front damper assembly 2 and the piston rod 203 of the right front damper assembly 2 are compressed and the piston rod 203 of the left rear damper assembly 2 and the piston rod 203 of the right rear damper assembly 2 are pulled, oil in the lower chamber 2012 of the left front damper assembly 2 flows through the sixth pipe line into the upper chamber 2011 of the left rear damper assembly 2, causing the piston rod 203 of the left rear damper assembly 2 to descend.

[0178] The oil in the lower chamber 2012 of the right front damper assembly 2 flows through the eighth pipe into the upper chamber 2011 of the right rear damper assembly 2, lowering the piston rod 203 of the right rear damper assembly 2. This allows the hydraulic suspension system 1000 to provide an anti-pitching force to prevent the vehicle from continuing to pitch.

[0179] By forming the third and fourth circuits, it is possible to achieve linked adjustment of the right front damper assembly 2, the right rear damper assembly 2, the left front damper assembly 2, and the left rear damper assembly 2, and further to provide an anti-pitching moment to ensure that the vehicle does not continue to pitch. The rigidity of the hydraulic suspension system 1000 can be adjusted by controlling the opening and closing states of the third adjusting valve 20 and the fourth adjusting valve 21. For example, closing the third adjusting valve 20 and the fourth adjusting valve 21 can improve the rigidity of the hydraulic suspension system 1000.

[0180] Of course, it will be understood that the above oil flow path description is merely an exemplary explanation to introduce the anti-pitching principle, and by utilizing the above anti-pitching principle, when the rear side is compressed and the front side is pulled, the hydraulic suspension system 1000 can provide an anti-pitching force.

[0181] As can be understood, when the hydraulic suspension system 1000 according to the embodiment of the present application is applied to an off-road vehicle, in order to improve the off-road RTI index, as shown in Fig. 19, the third regulating valve 20 is closed, the fourth regulating valve 21 is closed, the central accumulator regulating valve 32 is closed, the four first control valves 3 are closed, the first on-off valve 22 is closed, and the second on-off valve 23 is closed. The first height regulating valve 6 is opened, and the second height regulating valve 7 is opened.

[0182] By utilizing the above-mentioned anti-roll and height-maintaining principles, when an off-road vehicle travels on a steep mountain road, the hydraulic suspension system 1000 can provide anti-roll force and vehicle height-maintaining force, making it less likely that a roll phenomenon will occur. [Example]

[0183] As shown in FIG. 20, in this embodiment, compared with the first embodiment, the hydraulic suspension system 1000 according to the embodiment of the present application further includes a central control cylinder 24, a first height maintaining branch path, and a second height maintaining branch path.

[0184] The central control cylinder 24 includes a second cylinder 240 and a movable member 241. The movable member 241 is movably disposed within the second cylinder 240 and cooperates with the second cylinder 240 to define a first chamber 243, a second chamber 244, a third chamber 245 and a fourth chamber 246. The first chamber 243, the second chamber 244, the third chamber 245 and the fourth chamber 246 are arranged in order in the moving direction of the movable member 241. The first chamber 243 and the second chamber 244 are located on one side of an intermediate contact portion 2411 of the movable member 241, and the third chamber 245 and the fourth chamber 246 are located on the other side of the intermediate contact portion 2411. The intermediate contact portion 2411 movably engages with the inner wall of the second cylinder 240.

[0185] The oil passage 204 of the left front damper assembly 2 is connected to one of the first chamber 243 and the second chamber 244, and the oil passage 204 of the right rear damper assembly 2 is connected to the other of the first chamber 243 and the second chamber 244. The oil passage 204 of the left rear damper assembly 2 is connected to one of the third chamber 245 and the fourth chamber 246, and the oil passage 204 of the right front damper assembly 2 is connected to the other of the third chamber 245 and the fourth chamber 246. For convenience of explanation, the principle will be explained below using as an example a case where the oil passage 204 of the left front damper assembly 2 is connected to the first chamber 243, the oil passage 204 of the right rear damper assembly 2 is connected to the second chamber 244, the oil passage 204 of the left rear damper assembly 2 is connected to the third chamber 245, and the oil passage 204 of the right front damper assembly 2 is connected to the fourth chamber 246.

[0186] Specifically, when the vehicle tends to roll, for example, when the piston rods 203 of the left front damper assembly 2 and the left rear damper assembly 2 are compressed and the piston rods 203 of the right front damper assembly 2 and the right rear damper assembly 2 are pulled, the oil in the lower chamber 2012 of the left front damper assembly 2 flows into the first chamber 243 through the oil passage 204, and the oil in the lower chamber 2012 of the left rear damper assembly 2 flows into the third chamber 245 through the oil passage 204, and the oil in the first chamber 243 flows into the third chamber 245 through the oil passage 204. Since the first chamber 243 and the third chamber 245 are located on both sides of the intermediate contact portion 2411, the direction of the force of the oil in the first chamber 243 acting on the intermediate contact portion 2411 is opposite to the direction of the force of the third chamber 245 acting on the intermediate contact portion 2411, and the two opposite acting forces cancel each other out, so that the moving member 241 does not move, thereby suppressing the movement of the piston rod 203 of the left front damper assembly 2 and the piston rod 203 of the left rear damper assembly 2, and thereby playing a role in suppressing roll.

[0187] When the left front wheel of the vehicle encounters an obstacle such as a stone, the left front wheel lifts up and the compression width of the left front damper assembly 2 becomes greater than the compression width of the left rear damper assembly 2. In this case, the amount of oil flowing from the left front damper assembly 2 into the first chamber 243 becomes greater than the amount of oil flowing from the left rear damper assembly 2 into the third chamber 245, causing the moving member 241 to move to the right and press the third chamber 245 and the fourth chamber 246. The oil in the third chamber 245 flows into the lower chamber 2012 of the left rear damper assembly 2 and moves the piston rod 203 upward, and the oil in the fourth chamber 246 flows into the lower chamber 2012 of the right front damper assembly 2 and moves the piston rod 203 upward, thereby reducing the possibility of the left rear wheel and right front wheel leaving the ground and improving the stability of the vehicle.

[0188] Of course, it is understood that the above several situations are merely illustrative, and when the vehicle encounters other modes such as right front wheel lift, left rear wheel lift, etc., the oil will flow according to the above interlocking principle to prevent the vehicle from rolling, and each mode will not be described in detail here.

[0189] The first height maintaining branch path is connected to the oil passage 204 of the left front damper assembly 2 and the oil passage 204 of the right front damper assembly 2, and the first height maintaining branch path is provided with a first height control valve 6 for opening or closing the path.

[0190] The second height maintaining branch path is connected to the oil passage 204 of the left rear damper assembly 2 and the oil passage 204 of the right rear damper assembly 2, respectively, and the second height maintaining branch path is provided with a second height control valve 7 for opening or closing the path.

[0191] Specifically, when the first height control valve 6 is opened, the first height maintenance branch is open, and when the first height control valve 6 is closed, the first height maintenance branch is closed. When the second height control valve 7 is opened, the second height maintenance branch is open, and when the second height control valve 7 is closed, the second height maintenance branch is closed.

[0192] When it is necessary to maintain the height of the vehicle body, the hydraulic suspension system 1000 can be switched to a height maintenance mode, in which the first height control valve 6 and the second height control valve 7 are both opened, the first height maintenance branch path and the second height maintenance branch path are connected, the oil passage 204 of the left front damper assembly 2 communicates with the oil passage 204 of the right front damper assembly 2, and the oil passage 204 of the left rear damper assembly 2 communicates with the oil passage 204 of the right front damper assembly 2. right The piston rod 203 of the left front damper assembly 2 and the piston rod 203 of the right front damper assembly 2 are in an interlocking state, and the piston rod 203 of the left rear damper assembly 2 and right The piston rod 203 of the rear damper assembly 2 is in an interlocking state, which allows the vehicle body to maintain its current height as much as possible. [Example]

[0193] As shown in FIG. 21, in this embodiment, compared with the eighth embodiment, the hydraulic suspension system 1000 according to the embodiment of the present application does not include the second control valve 12, and the hydraulic suspension system 1000 includes a central accumulator 13.

[0194] In this embodiment, in the pressure increasing mode, the oil in the tank 1 flows to the central accumulator 13 and the second accumulator 10 and accumulates there.

[0195] The modes of the hydraulic suspension system 1000 of this embodiment are the same as those in the eighth embodiment, and will not be described here.

[0196] It should be noted that the above nine embodiments are merely illustrative and do not comprehensively describe the modes of the hydraulic suspension system 1000. The above nine embodiments all have the lift mode, height reduction mode, damping adjustment mode, etc. mode etc., and the description of each embodiment will be omitted here.

[0197] A vehicle according to an embodiment of the present application includes the hydraulic suspension system 1000 described in any of the above embodiments of the present application.

[0198] The vehicle according to the embodiment of the present application can adjust the height of the vehicle body according to road conditions, etc. For example, when traveling on a steep mountain road, the vehicle can enter a lift mode to raise the center of gravity of the vehicle and improve the stability of the vehicle. When it is necessary to reduce the impact of the vehicle body on the traveling speed, the vehicle can enter a height reduction mode to lower the center of gravity of the vehicle. Of course, it should be understood that the above is merely an exemplary description, and the height of the vehicle body may be adjusted according to actual needs during traveling.

[0199] The vehicle according to the embodiment of the present application can adjust the height of the vehicle body, improving vehicle handling stability without compromising vehicle comfort, thereby effectively resolving the trade-off between vehicle comfort and handling stability. Furthermore, the use of a hollow piston rod 203 not only reduces weight, but also allows the position of the piston rod 203 to be adjusted by utilizing an oil passage 204 defined by the hollow piston rod 203 to allow oil to flow in or out, resulting in a simple adjustment method, high reliability, low cost, and fast response. Furthermore, the piston rod 203 is provided with an oil passage 204 communicating with the lower chamber 2012, and the oil passage 204 is connected to a reservoir, thereby stabilizing the connection of the oil circuit, avoiding wear due to vibration at the connection points, and minimizing oil leakage at the connection points.

[0200] Other configurations and operations of vehicle braking systems, etc., according to embodiments of the present application are known to those skilled in the art and will not be described in detail herein.

[0201] In the description of this application, the orientations or positional relationships indicated by terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" are based on the orientations or positional relationships shown in the drawings, and are intended merely to facilitate and simplify the description of this application. They do not indicate or suggest that the devices or parts shown must have a specific orientation and be configured and operate in a specific orientation, and therefore should not be understood as limiting the application.

[0202] Additionally, the terms "first" and "second" are for descriptive purposes only and should not be understood to denote or suggest relative importance or to implicitly indicate the number of technical features depicted. Thus, a feature qualified with "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of this application, "plurality" means two or more unless explicitly and specifically limited.

[0203] In this application, unless otherwise clearly specified or limited, the terms "attached," "coupled," "connected," "fixed," etc. should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, an internal communication between two parts, or an interactive relationship between two parts. Those skilled in the art can understand the specific meanings of the above terms in this application according to specific circumstances.

[0204] In this application, unless otherwise clearly specified or limited, a first feature being "above" or "below" a second feature may include direct contact between the first and second features, or indirect contact between the first and second features via an intermediate medium. Furthermore, a first feature being "above," "above," or "on the upper surface" of a second feature may include the first feature being directly above or diagonally above the second feature, or may simply mean that the horizontal height of the first feature is higher than that of the second feature. A first feature being "below," "below," or "on the lower surface" of a second feature may include the first feature being directly below or diagonally below the second feature, or may simply mean that the horizontal height of the first feature is lower than that of the second feature.

[0205] In the description herein, references to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean that the specific features, structures, materials, or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the description herein, the exemplary expressions of the above terms are not necessarily limited to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be appropriately combined in any one or more embodiments or examples. Furthermore, if not mutually inconsistent, a person skilled in the art may combine or combine different embodiments or examples described herein and features of different embodiments or examples.

[0206] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are illustrative and should not be construed as limiting the present application, and that those skilled in the art may make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application. [Explanation of symbols]

[0207] 1000 Hydraulic Suspension System 1 tank 2 Damper Assembly 200 Damper 201 Damper housing 2011 Upper Chamber 2012 Lower Chamber 202 Piston 203 Piston rod 204 Oil passage 205 vibration damping spring 3. First control valve 6. First height control valve 7 Second height control valve 8. Opening adjustment valve 9 First Accumulator 10 Second accumulator 101 Metal Bellows 11 Stiffness adjustment valve 12 Second control valve 13 Central Accumulator 32 Central pressure regulator 14 First Adjustment Accumulator 15 Second Adjustment Accumulator 16 Third Adjustment Accumulator 17 4th Adjustment Accumulator 18 First adjusting valve 19 Second adjusting valve 20 Third adjusting valve 21 Fourth adjusting valve 22 First shut-off valve 23 Second shut-off valve 24 Central Control Cylinder 240 No. 2 cylinder 241 Moving parts 2410 Mobile main body 2411 Intermediate contact part 243 Chamber 1 244 Second Chamber 245 Third Chamber 246 4th Chamber 247 First return spring 248 Second return spring 249 Guide Assembly 2490 First guide member 2491 Second guide member 26 Control pump 260 Control valve body 261 Drive motor 27 Oil return valve 28 Check valve 29 Pressure Stabilizing Accumulator 30 Pressure reducing accumulator 31 Relief valve 33 Common passage 34 Oil discharge branch 35 Oil return branch

Claims

1. A hydraulic suspension device for adjusting the height of a vehicle body, a reservoir and a damper, The reservoir is provided on a vehicle body and configured to store oil. the damper has a damper housing, a piston, and a piston rod, the damper housing is configured to be connected to an axle, the piston is located within the damper housing and defines an upper chamber and a lower chamber in cooperation with the damper housing, one end of the piston rod is connected to the piston, the piston rod is configured to be connected to a vehicle body, an oil passage is provided within the piston rod, the oil passage communicates with the lower chamber and the reservoir, thereby allowing oil to flow between the reservoir and the lower chamber, an accumulator module, the oil passage communicating with the reservoir via a connecting passage, the accumulator module communicating with the connecting passage and configured to adjust at least one of the damping and stiffness of the damper and a body height of the vehicle; The accumulator module includes a first accumulator and an opening adjustment valve, the first accumulator communicating with the connecting passage at a first connection point, the opening adjustment valve being provided between the first connection point and the oil passage, the opening adjustment valve adjusting the opening of the connecting passage between the oil passage and the first connection point to adjust the damping of the damper, and further adjusting the rigidity of the damper by closing the connecting passage between the oil passage and the first connection point. Hydraulic suspension system.

2. 2. The hydraulic suspension device according to claim 1, wherein the reservoir includes a control pump and a tank, the control pump being provided between the tank and the oil passage.

3. 2. The hydraulic suspension device according to claim 1, wherein an upper end of the piston rod extends from the damper housing, and an oil port is formed at the upper end of the piston rod, connecting the oil passage with the reservoir.

4. 3. The hydraulic suspension device according to claim 2, further comprising an oil discharge passage and an oil return passage, the oil discharge passage and the oil return passage both communicating between the tank and the oil passage and partially overlapping each other, and the control pump being provided in the oil discharge passage.

5. 5. The hydraulic suspension device according to claim 4, wherein the oil discharge passage includes a common passage and an oil discharge branch passage, the oil return passage includes the common passage and an oil return branch passage, one end of the common passage communicates with the oil passage, and the oil discharge branch passage and the oil return branch passage are both connected to the other end of the common passage.

6. 6. The hydraulic suspension device according to claim 5, wherein a check valve and the control pump are provided in the oil discharge branch path, one end of the check valve communicates with the common passage and the other end communicates with the control pump, and an oil return valve is provided in the oil return branch path.

7. 2. The hydraulic suspension device according to claim 1, further comprising a first control valve provided in the connecting passage and controlling communication or cutoff between the reservoir and the accumulator module.

8. 2. The hydraulic suspension device according to claim 1, wherein the accumulator module further includes a second accumulator and a stiffness adjustment valve, the connecting passage having a second connection point that communicates with the second accumulator, the stiffness adjustment valve being provided between the second accumulator and the second connection point and adjusting stiffness of the damper by connecting or blocking communication between the connecting passage and the second accumulator.

9. 9. The hydraulic suspension system of claim 8, further comprising a second control valve disposed between the second connection point and the oil passage.

10. 2. The hydraulic suspension device of claim 1, wherein the accumulator module further includes a first accumulator and a second accumulator, the first accumulator communicating with the connecting passage at a first connection point, and the connecting passage having a second connection point communicating with the second accumulator.

11. The hydraulic suspension device of claim 10, wherein the first connection point is located between the oil passage and the second connection point.

12. The hydraulic suspension system of claim 10, further comprising a second control valve disposed between the first connection point and the second connection point.

13. 13. A hydraulic suspension system comprising: a controller; and the hydraulic suspension device according to any one of claims 1 to 12, wherein the controller controls a flow direction of oil between the reservoir and the damper according to a vehicle situation, thereby increasing or decreasing a body height of the vehicle.

14. A vehicle comprising the hydraulic suspension system of claim 13.

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