Hydraulic suspension system

Abstract

The application discloses a hydraulic suspension system, which selects a double-acting oil-gas spring, cross-communicates left and right suspension oil paths, and improves the anti-unbalance load capacity of a chassis. A high-performance height adjusting valve block is adopted, so that the stability of the suspension height can be ensured through the first oil-gas spring, the second oil-gas spring, the height adjusting valve block, the first energy accumulator, the second energy accumulator, an oil inlet stop valve, a one-way valve, a motor pump, a hydraulic oil tank, an oil return filter and an oil return stop valve, and the suspension can be dynamically height adjusted during running, so that the hydraulic suspension system has the characteristics of convenience, reliability and high precision compared with a traditional hydraulic suspension system. That is to say, the hydraulic suspension system meets the requirements of height adjustment, cushioning, shock absorption, inherent frequency adjustment and the like of the hydraulic suspension system, and also meets the requirement of dynamic height adjustment of the vehicle during running, so that the anti-unbalance load capacity of the vehicle can be ensured, and the vehicle has the capability of dynamic height adjustment during running.

Description

Technical Field

[0001] This application relates to the field of hydraulic suspension system technology, and more particularly to a hydraulic suspension system. Background Technology

[0002] Traditional hydraulic suspension systems primarily consist of hydraulic components such as gas springs, accumulators, and height adjustment valve blocks. The gas springs and accumulators are connected in series, providing vibration damping and cushioning. Traditional hydraulic suspension systems use single-acting gas springs, meaning the springs on each side of the vehicle are not connected, resulting in poor off-center load capacity. Furthermore, traditional suspension systems cannot dynamically adjust the height, failing to meet suspension height requirements during vehicle movement. Summary of the Invention

[0003] This application provides a hydraulic suspension system that can satisfy the functions of hydraulic suspension systems such as height adjustment, buffering, shock absorption, and adjustment of the vehicle's natural frequency, as well as the requirements for dynamic height adjustment of the vehicle during driving, thereby ensuring the vehicle's resistance to eccentric loads and enabling the vehicle to dynamically adjust its height during driving.

[0004] In a first aspect, this application provides a hydraulic suspension system, characterized in that the system includes a first hydraulic spring, a second hydraulic spring, a first accumulator, a second accumulator, a height adjustment valve block, an oil inlet shut-off valve, a check valve, a motor pump, a hydraulic oil tank, a return oil filter, and a return oil shut-off valve.

[0005] The first hydraulic spring and the first accumulator are connected to the height adjustment valve block; the second hydraulic spring and the second accumulator are connected to the height adjustment valve block; wherein, the first hydraulic spring and the second hydraulic spring are used to perform the dynamic height adjustment hydraulic system operation and provide support for the frame; the first hydraulic spring and the second hydraulic spring are used to control the height of the frame, and the first accumulator and the second accumulator are used for buffering and shock absorption;

[0006] The first port of the height adjustment valve block is connected to the hydraulic oil tank through the return oil filter and the return oil shut-off valve;

[0007] The second port of the height adjustment valve block is connected to the hydraulic oil tank through the oil inlet shut-off valve, the check valve, and the motor pump;

[0008] The height adjustment valve block is used to control the output or storage of hydraulic oil from the hydraulic oil tank to control the extension and retraction of the first and second hydraulic springs, thereby adjusting the height of the vehicle frame.

[0009] As can be seen from the above technical solution, this application provides a hydraulic suspension system, the system including a first gas spring, a second gas spring, a first accumulator, a second accumulator, a height adjustment valve block, an inlet shut-off valve, a check valve, a motor pump, a hydraulic oil tank, a return oil filter, and a return oil shut-off valve; the first gas spring and the first accumulator are connected to the height adjustment valve block; the second gas spring and the second accumulator are connected to the height adjustment valve block; wherein, the first gas spring and the second gas spring are used to perform the dynamic height adjustment hydraulic system action and provide support for the vehicle frame; the first... The first and second hydraulic springs are used to control the height of the vehicle frame, and the first and second accumulators are used for buffering and shock absorption. The first port of the height adjustment valve block is connected to the hydraulic oil tank through the return oil filter and the return oil shut-off valve. The second port of the height adjustment valve block is connected to the hydraulic oil tank through the inlet shut-off valve, the check valve, and the motor pump. The height adjustment valve block is used to control the extension and retraction of the first and second hydraulic springs by controlling the output or storage of hydraulic oil from the hydraulic oil tank, so as to adjust the height of the vehicle frame. Therefore, the hydraulic suspension system of this application uses double-acting hydraulic springs, which cross-connect the left and right suspension oil circuits, improving the chassis's ability to resist eccentric loads. A high-performance height adjustment valve block is employed. Through the first and second hydraulic springs, the height adjustment valve block, the first and second accumulators, the inlet shut-off valve, the check valve, the motor pump, the hydraulic oil tank, the return oil filter, and the return oil shut-off valve, the stability of the suspension height is ensured. This also allows the suspension to be dynamically adjusted during driving. Therefore, compared to traditional hydraulic suspension systems, the hydraulic suspension system of this application is convenient, reliable, and highly precise. In other words, the hydraulic suspension system of this application not only fulfills the functions of a hydraulic suspension system, such as height adjustment, buffering, shock absorption, and adjustment of the vehicle's natural frequency, but also meets the requirements for dynamic height adjustment during driving, thereby ensuring the vehicle's resistance to eccentric loads and providing the ability to dynamically adjust the vehicle's height while driving.

[0010] The further effects of the aforementioned non-conventional preferred method will be explained below in conjunction with specific embodiments. Attached Figure Description

[0011] To more clearly illustrate the embodiments of this application or the existing technical solutions, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This application provides a schematic diagram of the system architecture of a hydraulic suspension system according to an embodiment of the present application.

[0013] Figure 2 A flowchart illustrating the dynamic height adjustment strategy of a hydraulic suspension system provided in an embodiment of this application;

[0014] Figure 3 This is a schematic flowchart illustrating the height adjustment strategy of a hydraulic suspension system provided in an embodiment of this application. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0016] The various non-limiting embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0017] See Figure 1 The present invention illustrates a hydraulic suspension system in an embodiment of the present application. The system includes a first hydraulic spring 1, a second hydraulic spring (1), a first accumulator 2, a second accumulator (2), a height adjustment valve block 4, an oil inlet shut-off valve 14, a check valve 15, a motor pump 16, a hydraulic oil tank 17, a return oil filter 18, and a return oil shut-off valve 19.

[0018] The first hydraulic spring 1 and the first accumulator 2 are connected to the height adjustment valve block 4; the second hydraulic spring (1) and the second accumulator (2) are connected to the height adjustment valve block 4.

[0019] The first hydraulic spring 1 and the second hydraulic spring (1) are used to perform the dynamic height adjustment hydraulic system action and provide support for the frame; the first hydraulic spring 1 and the second hydraulic spring (1) are used to control the height of the frame; and the first accumulator 2 and the second accumulator (2) are used for buffering and shock absorption.

[0020] The double-acting gas spring (first gas spring 1, second gas spring (1)) is the actuator of the dynamic height adjustment hydraulic system, which provides support for the frame. The height of the frame is controlled by controlling the extension and retraction of the double-acting gas spring. The first gas spring 1, the second gas spring (1), the first accumulator 2, and the second accumulator (2) are connected in series to buffer and dampen the shock.

[0021] It should be noted that in this embodiment, the change angle of the suspension arm can be detected by an angle sensor, and the height of the first gas spring 1 and the second gas spring (1) can be calculated by angle conversion, so that the height of the first gas spring 1 and the second gas spring (1) can be controlled to achieve closed-loop control of the vehicle chassis and frame movement. In addition, the circuit is symmetrically arranged with double-acting gas springs (i.e., the first gas spring 1 and the second gas spring (1)) to evenly distribute the chassis load. At the same time, the gas springs on both sides (i.e., the first gas spring 1 and the second gas spring (1)) are cross-connected, and the pressure of the positive cavity of one gas spring is simultaneously transmitted to the negative cavity of the other gas spring, which can maximize the stability of the vehicle when tilting. In one implementation, the system can set a damping hole between the positive and negative cavities of the gas spring to reduce the pressure impact of the accumulator pressure on the positive and negative cavities of the gas spring when the pressure is released upon landing.

[0022] It should be noted that, in one implementation, this system can adopt a piston-type accumulator and a hydraulic-gas spring-oil separation structure, with two hydraulic-gas springs on one side of the front axle paired with one accumulator, and three hydraulic-gas springs on one side of the rear axle paired with two accumulators.

[0023] The first port of the height adjustment valve block 4 is connected to the hydraulic oil tank 17 through the return oil filter 18 and the return oil shut-off valve 19. The second port of the height adjustment valve block 4 is connected to the hydraulic oil tank 17 through the inlet shut-off valve 14, the one-way valve 15, and the motor pump 16.

[0024] The height adjustment valve block 4 controls the output or storage of hydraulic oil from the hydraulic oil tank 17 to control the extension and retraction of the first and second hydraulic springs (1), thereby adjusting the height of the vehicle frame. The return oil filter 18 purifies the hydraulic oil flowing back to the hydraulic oil tank 17; the return oil shut-off valve 19 controls the opening and closing of the hydraulic oil flow channel back to the hydraulic oil tank 17. The inlet shut-off valve 14 controls the opening and closing of the hydraulic oil flow channel out of the hydraulic oil tank 17; the motor pump 16 outputs high-pressure oil; and the one-way valve 15 prevents high-pressure oil from flowing back to the motor pump 16.

[0025] In one implementation, the height adjustment valve block 4 may include: a pressure measuring connector 5, a plate-type shut-off valve 6, a solenoid directional valve 7, a balance valve 8, a hydraulic check valve 159, a proportional directional valve 10, a shuttle valve 11, a differential pressure reducing valve 12, and a pressure sensor 13.

[0026] The pressure testing connector 5 and the pressure sensor 13 are used to measure the system pressure. In one implementation, the system can be equipped with three pressure sensors 13, which are used to measure the system pressure and the pressure of the positive and negative chambers of the oil-gas spring during the adjustment process, respectively.

[0027] The plate-type shut-off valve 6 is used to provide a manual shut-off function.

[0028] The electromagnetic reversing valve 7 and the proportional directional valve 10 work together to control the movement of the hydraulic suspension system.

[0029] The proportional directional valve 10 is also used to control the extension and retraction speed of the first gas spring 1 and the second gas spring (1); the height adjustment valve block 4 can use the proportional directional valve 10 to control the height of the suspension. By adjusting the valve opening of the proportional directional valve 10, the suspension can be raised or lowered. The input PWM signal can continuously and proportionally control the system pressure and flow, and realize high-precision adjustment of the displacement and speed of the gas spring.

[0030] In one implementation, the system can use a pressure compensator and a proportional directional valve 10 together to ensure the stability of the input oil-gas spring flow.

[0031] The balance valve 8 is used to improve the stability of speed control during descent under heavy loads, and also, in conjunction with the hydraulically controlled check valve 159, to reduce leakage when the hydraulic suspension system is not in operation. The height adjustment valve block 4 is equipped with the balance valve 8, which enables smooth landing of the suspension under heavy loads. When the suspension needs to be lowered, the balance valve 8 makes the landing more stable, while also reducing oil leakage and improving system sealing.

[0032] The shuttle valve 11 is used to collect the load pressure of the hydraulic suspension system when the suspension is adjusted.

[0033] The differential pressure reducing valve 12 is used to control the stability of the pressure difference before and after the proportional directional valve 10.

[0034] Understandably, the height adjustment valve block 4 is a key part of the system, containing components such as pressure testing connector 5, plate shut-off valve 6, solenoid directional valve 7, balance valve 8, hydraulic check valve 159, proportional directional valve 10, shuttle valve 11, differential pressure reducing valve 12, and pressure sensor 13 (suspension). The pressure testing connector 5 and pressure sensor 13 (suspension) measure system pressure. The plate shut-off valve 6 provides manual shut-off functionality. The solenoid directional valve 7 and proportional directional valve 10 work together to control the suspension hydraulic system's movement by controlling the valve's on / off state. The proportional directional valve 10 can also control the valve opening size to control the extension and retraction speed of the double-acting pneumatic spring. The balance valve 8 improves the stability of speed control during heavy load descent, and combined with the hydraulic check valve 159, it also minimizes leakage in the suspension hydraulic system when not in operation. The shuttle valve 11 senses the load pressure during suspension height adjustment, and the differential pressure reducing valve 12 stabilizes the pressure difference before and after the proportional directional valve 10.

[0035] One-way valve 15 is located at the oil outlet of motor pump 16. Motor pump 16 outputs pressurized oil as the oil source. One-way valve 15 can prevent high-pressure oil from flowing back to the pump and causing the pump to reverse. The function of hydraulic oil tank 17 is to store oil. The function of return oil filter 18 is to purify the hydraulic oil flowing back to hydraulic oil tank 17 and prevent excess material from contaminating the oil. The function of inlet shut-off valve 14 and return shut-off valve 19 is to control the opening and closing of the suspension's inlet and outlet oil circuits.

[0036] As can be seen, the system of this application adopts multiple anti-leakage measures, and sets up multiple seals such as hydraulic lock (i.e., hydraulic control check valve 159), balance valve 8, and solenoid valve (i.e., solenoid directional valve 7), which enhances the sealing ability of the suspension and prevents the large flow leakage that may occur in a single seal from causing a significant change in the vehicle frame height.

[0037] In one implementation, the system further includes a first locking valve block S1 and a second locking valve block S2. The first gas spring 1 and the first accumulator 2 are connected via the first locking valve block S1, which controls whether the first gas spring 1 and the first accumulator 2 are connected or isolated. The second gas spring (1) and the second accumulator (2) are connected via the second locking valve block S2, which controls whether the second gas spring (1) and the second accumulator (2) are connected or isolated. That is, the locking valve block can isolate the accumulator from the gas spring. When the system requires the suspension to remain rigid, the solenoid valve of the locking valve block can be closed, thus maintaining the rigidity of the suspension. The first locking valve block S1 and the second locking valve block S2 can provide a rigid locking function. When the vehicle speed is less than 2 km / h, the chassis is in rigid locking mode by default, and the suspension is rigid.

[0038] Specifically, the first locking valve block S1 and the second locking valve block S2 are used to control the chassis to adjust to a rigid locking mode and set the suspension to rigid if the vehicle corresponding to the hydraulic suspension system is in driving mode and the vehicle speed is less than or equal to a first preset threshold. Figure 2 As shown, when the vehicle speed is ≤2km / h (i.e. the first preset threshold), the solenoid valves between each hydropneumatic spring and the accumulator, as well as the solenoid valves in the cross-connecting oil circuits of the left and right hydropneumatic springs, are all in the closed state, the suspension system is rigidly locked, and the left and right hydropneumatic springs are isolated and not connected.

[0039] The first locking valve block S1 and the second locking valve block S2 are specifically used to control the chassis to adjust to a rigid locking mode and set the suspension to rigid if the vehicle corresponding to the hydraulic suspension system is in driving mode and the vehicle speed is greater than a second preset threshold. Figure 2As shown, when the vehicle speed is greater than 15 km / h (i.e., the second preset threshold), the solenoid valves between each hydropneumatic spring and the accumulator, as well as the solenoid valves in the cross-connecting oil circuits of the left and right hydropneumatic springs, are all in the open state, and the suspension system is in the elastic damping state.

[0040] If the vehicle corresponding to the hydraulic suspension system is in driving mode, the vehicle speed is greater than the first preset threshold and less than or equal to the second preset threshold, and the angle of the vehicle's chassis and the turning angle of the vehicle's front wheels meet the preset angle conditions, then the height adjustment valve block 4 is used to adjust the lengths of the first gas spring 1 and the second gas spring (1) according to the height of the vehicle's frame. Figure 2 As shown, when the vehicle speed 2 < V ≤ 15 km / h (i.e., the vehicle speed is greater than the first preset threshold and less than or equal to the second preset threshold), it is first determined whether the "Dynamic Height Adjustment Mode" in the height adjustment interface is selected. If it is not selected, no operation is performed, and the suspension remains in the elastic damping state. If the "Dynamic Height Adjustment Mode" is selected, it is determined by judging that the level tilt angle θ ≤ 2°, the front wheel turning angle ≤ 3°, and the vehicle has not performed braking operation (i.e., the angle of the vehicle chassis and the turning angle of the vehicle's front wheels meet the preset angle conditions). If all of the above conditions are met simultaneously, the rear axle steering oil source is switched to the suspension height adjustment to perform the dynamic height adjustment operation; otherwise, no operation is performed.

[0041] The dynamic height adjustment operation can be performed as follows:

[0042] If the height of the frame corresponding to one of the target sides of the chassis (left front, right front, left rear, right rear) is higher than the preset zero position, the height adjustment valve block 4 is specifically used to adjust the length of the gas spring corresponding to the target side according to the height of the target side; if the height of the frame corresponding to one of the target sides of the chassis (left front, right front, left rear, right rear) is lower than the preset zero position, the height adjustment valve block 4 is specifically used to adjust the length of the gas spring corresponding to the target side according to the height of the frame corresponding to the target side. For example, in the case where the height of one side of the frame is lower than the zero position:

[0043] 1) Raise the frame on that side to the zero position separately;

[0044] 2) If the other side frame is 10mm higher than the zero position after the movement, then lower that side frame to the zero position individually;

[0045] When the height of one side of the frame is higher than zero: Lower the frame of that side to zero;

[0046] When the railway transport mode is adjusted to zero:

[0047] 1) Use tilt sensors to detect the position of the frame on each side, and use closed-loop control to open the proportional directional valve 10, so that the frame is raised to the zero position synchronously;

[0048] 2) If, after leveling, one side of the frame is 10mm higher than the zero position, then lower that side of the frame to the zero position.

[0049] If the height of the chassis corresponding to at least a portion of the target sides (left front, right front, left rear, and right rear) is not at the preset balance position, the height adjustment valve block 4 is specifically used to adjust the length of the gas spring corresponding to the target side based on the height of the chassis corresponding to the at least a portion of the target side and the preset balance position. For example, Figure 3 As shown; assuming the initial height of each frame is less than the balance position (e.g., 770mm), level it to the balance position:

[0050] 1) If the height difference is less than 5mm, use the tilt sensor to control the BL opening in a closed loop so that the frame is raised to the balance position synchronously.

[0051] 2) If the height difference is greater than 5mm, then take the lowest frame as the reference and cyclically lower the other side frames individually until the height difference is less than 5mm, then repeat 1).

[0052] Assuming that the initial height of each frame is higher than the equilibrium position, level it to the equilibrium position:

[0053] 1) If the height difference is less than 5mm, use the tilt sensor to control the BL opening in a closed loop so that the frame can be lowered to the balance position synchronously.

[0054] 2) If the height difference is greater than 5mm, then take the lowest frame as the reference and cyclically lower the other side frames individually until the height difference is less than 5mm, then repeat 1).

[0055] Assume that the initial height of each frame is partially above the equilibrium position and partially below the equilibrium position:

[0056] 1) Using the lowest frame height as a reference, lower the height of the other frames so that the height difference between the frames is no more than 5mm.

[0057] 2) Use a tilt sensor to control the BL opening in a closed loop, so that the frame is raised to the equilibrium position synchronously.

[0058] Next, referring to Table 1, the basic operation of the hydraulic suspension system will be introduced:

[0059] The dynamic height adjustment suspension hydraulic system allows for active raising or lowering of the suspension when the vehicle is unloaded or fully loaded, and also enables dynamic height adjustment while in motion. Specifically, it includes the following functions: stiffening action, unilateral raising, unilateral lowering, simultaneous raising, simultaneous lowering, one-button height adjustment, and dynamic height adjustment.

[0060] The system uses motor pump 16 as the oil source. The oil flows through check valve 15 and is connected to port P of height adjustment valve block 4. Ports A1 and B1 of height adjustment valve block 4 are connected to the left front double-acting pneumatic spring, and ports A2 and B2 of height adjustment valve block 4 are connected to the right front double-acting pneumatic spring. The accumulator is connected to the positive cavity of the double-acting pneumatic spring. The oil circuit between the double-acting pneumatic spring and the accumulator is controlled by a locking valve block. Port T of height adjustment valve block 4 is connected to hydraulic oil tank 17.

[0061] Rigidification action:

[0062] All locking valve blocks and the electromagnets in the locking valve blocks are de-energized, the accumulator is isolated from the double-acting oil spring [1], the left and right oil springs are isolated, and the suspension hydraulic system is in a rigid state.

[0063] Unilateral elevation:

[0064] The single-sided air spring is raised using a differential raising method. For example, raising the left front side: set a certain opening at BL2 in the height adjustment valve block 4, energize S1 and S2 in the height adjustment valve block 4, and energize S5 and S6 in the height adjustment valve block 4. Oil enters the positive cavity of the left front air spring, and oil from the reverse cavity of the left front air spring enters the positive cavity of the right front air spring, pushing the right front air spring to extend. Oil from the reverse cavity of the right front air spring enters the positive cavity of the left front air spring. At this time, the right front air spring also extends at the same time as the left front air spring extends, and the frame height also increases accordingly, thereby realizing differential control of the air spring action. For example, if the left frame is raised by 3.5mm, the right frame is raised by 1mm.

[0065] Unilateral decrease:

[0066] The single-sided air spring is lowered independently, with the left and right air springs isolated. The air springs on the left front, right front, left rear, and right rear sides do not affect each other. For example, when lowering the height of the left side frame: S1, S2, and S3 of the height adjustment valve block 4 are energized, and BL1 of the height adjustment valve block 4 is set to a certain opening degree. At this time, the oil source pressure is 16MPa, and the balance valve 8 corresponding to the positive cavity of the air spring is opened. The oil in the positive cavity of the air spring flows back to the oil tank (i.e., hydraulic oil tank 17) through the balance valve 8, the hydraulic control check valve 159, and the proportional directional valve 10. The length of the air spring is shortened, and the height of the frame is lowered.

[0067] Synchronous rise:

[0068] When the air springs are raised synchronously, each air spring on each side is raised differentially. At this time, the proportional directional valve 10 in the height adjustment valve block 4 assembly that controls the action of the left front and right front air springs opens simultaneously. The oil flows into the positive cavity of the air spring, pushing the air spring to extend and raising the height of the frame. At the same time, the oil in the reverse cavity of the air spring flows into the positive cavity of the opposite air spring, realizing the synchronous raising of the frame.

[0069] Synchronous reduction:

[0070] Each gas spring utilizes a unilateral lowering method. The tilt sensors in the system determine the height of the chassis at the left front, right front, left rear, and right rear. If the chassis height needs to be lowered, the proportional directional valve 10 controls the shortening of each gas spring. The opening of the proportional directional valve 10 controls the speed of the gas spring's movement, achieving synchronous lowering.

[0071] Table 1. Excitation Table for Suspension Hydraulic System Operation

[0072]

[0073]

[0074] It should be noted that S1-S6 and BL1-BL4 are... Figure 1 Locations S1-S6 and BL1-BL4.

[0075] As can be seen, this system achieves suspension state control at different vehicle speeds by optimizing the control strategy and combining it with a high-performance suspension hydraulic system. There are corresponding suspension modes for low speed, medium speed, and high speed, making the suspension more adaptable.

[0076] Based on the above technical solution, the effects of the hydraulic suspension system are as follows:

[0077] 1) High-precision adjustable suspension;

[0078] The suspension hydraulic system adopts a combination of oil-air springs and accumulators, evenly distributed on the left and right. The flow of the suspension oil circuit on each side is controlled by the electromagnetic reversing valve 7 of the height adjustment valve block 4 to achieve closed-loop control of the chassis height. The electromagnetic reversing valve 7 adopts a high-precision proportional solenoid valve, which can be continuously adjusted to achieve high-precision control of the chassis height.

[0079] 2) Suspension dynamic adjustment function;

[0080] When the vehicle is at a speed of 2 < V ≤ 15 km / h, the suspension hydraulic system can perform dynamic adjustments. If the vehicle is switched to dynamic height adjustment mode at this time, and the chassis level angle θ ≤ 2°, the front wheel steering angle ≤ 3°, and the vehicle is not braking, dynamic height adjustment can be performed while the vehicle is in motion.

[0081] 3) Anti-roll function;

[0082] The suspension hydraulic system uses a cross-interconnected design of the two sides of the air springs, so that when one side of the air spring is under load, the load can be transferred to the other side of the air spring. When the suspension is under uneven load, the load can be distributed more evenly on the frame, preventing the chassis from tilting due to excessive load difference on both sides of the frame.

[0083] 4) Suspension stiffness / elasticity switching function;

[0084] The vehicle has a rigid-flexible switching function. When the chassis is in low speed mode, the locking valve block (i.e., the first locking valve block S1 and the second locking valve block S2) is not energized and is in a closed state, and the left and right oil-gas springs (i.e., the first oil-gas spring 1 and the second oil-gas spring (1)) are not connected to each other. At this time, the vehicle is in rigid locking mode. If the vehicle speed is >2km / h, the dynamic height adjustment mode or elastic damping mode can be selected according to the user's needs and actual situation.

[0085] 5) High reliability of suspension landing

[0086] The suspension hydraulic system height adjustment valve block 4 is equipped with a balance valve 8. When the chassis needs to be lowered, in order to ensure that the chassis lowering speed is controlled and to prevent the chassis from falling suddenly and quickly, the balance valve 8 needs to be opened by supplying oil pressure before the suspension can be lowered. After the balance valve 8 is opened, the maximum landing speed of the chassis is limited by the balance valve 8, which can achieve landing stability.

[0087] 6) High reliability of the seal

[0088] The dynamic height adjustment suspension hydraulic system is equipped with a triple seal consisting of a solenoid valve (i.e., solenoid directional valve 7), a balance valve 8, and a hydraulic lock (i.e., hydraulic control check valve 159) to ensure stable and reliable suspension position and avoid excessive changes in vehicle frame height due to leakage of hydraulic valve components.

[0089] 7) Precision of flow regulation

[0090] The differential pressure reducing valve 12 and the proportional directional valve 10 in the height adjustment valve block 4 are used together to make the pressure difference before and after the proportional directional valve 10 almost consistent. When the proportional directional valve 10 is used for flow regulation, it is less affected by the pressure difference and can achieve precise flow control.

[0091] 8) Safety performance

[0092] The system employs a triple seal consisting of a solenoid valve (i.e., solenoid directional valve 7), a balance valve 8, and a hydraulic lock (i.e., hydraulic control check valve 159) to ensure the reliability of the seal. At the same time, a plate-type shut-off valve 6 is used to provide redundancy backup, avoiding abnormal changes in the vehicle frame height caused by unstable valve performance. In addition, the system can also use an angle sensor to monitor the suspension height in real time, ensuring the controllability of the suspension height.

[0093] As can be seen from the above technical solution, this application provides a hydraulic suspension system, which includes a first pneumatic spring 1, a second pneumatic spring (1), a first accumulator 2, a second accumulator (2), a height adjustment valve block 4, an oil inlet shut-off valve 14, a one-way valve 15, a motor pump 16, a hydraulic oil tank 17, a return oil filter 18, and a return oil shut-off valve 19; the first pneumatic spring 1 and the first accumulator 2 are connected to the height adjustment valve block 4; the second pneumatic spring (1) and the second accumulator (2) are connected to the height adjustment valve block 4; wherein, the first pneumatic spring 1 and the second pneumatic spring (1) are used to perform the dynamic height adjustment hydraulic system action and provide support for the vehicle frame; The first and second air springs (1) are used to control the height of the vehicle frame, and the first and second accumulators (2) are used for buffering and shock absorption. The first port of the height adjustment valve block 4 is connected to the hydraulic oil tank 17 through the return oil filter 18 and the return oil shut-off valve 19. The second port of the height adjustment valve block 4 is connected to the hydraulic oil tank 17 through the inlet shut-off valve 14, the check valve 15, and the motor pump 16. The height adjustment valve block 4 is used to control the extension and retraction of the first and second air springs (1) by controlling the output or storage of hydraulic oil from the hydraulic oil tank 17, so as to adjust the height of the vehicle frame. It can be seen that the hydraulic suspension system of this application uses double-acting air springs, which cross-connect the suspension oil circuits on the left and right sides, thereby improving the chassis's ability to resist eccentric loads. A high-performance height adjustment valve block 4 is adopted. Through the first hydraulic spring 1, the second hydraulic spring (1), the height adjustment valve block 4, the first accumulator 2, the second accumulator (2), the inlet shut-off valve 14, the check valve 15, the motor pump 16, the hydraulic oil tank 17, the return oil filter 18, and the return oil shut-off valve 19, the stability of the suspension height can be ensured, and the suspension can be dynamically adjusted during driving. Therefore, compared with traditional hydraulic suspension systems, the hydraulic suspension system of this application is convenient, reliable, and highly precise. In other words, the hydraulic suspension system of this application not only satisfies the functions of height adjustment, buffering, shock absorption, and adjustment of the vehicle's natural frequency, but also meets the requirements for dynamic height adjustment during driving, thereby ensuring the vehicle's resistance to eccentric loads and enabling dynamic height adjustment during driving.

[0094] The various embodiments in this application are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the system embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the system embodiments.

[0095] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, system, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, system, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, system, article, or apparatus that includes said element.

[0096] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A hydraulic suspension system, characterized in that, The system includes a first hydraulic spring, a second hydraulic spring, a first accumulator, a second accumulator, a height adjustment valve block, an oil inlet shut-off valve, a check valve, a motor pump, a hydraulic oil tank, a return oil filter, and a return oil shut-off valve; the first hydraulic spring and the second hydraulic spring are arranged symmetrically on the left and right sides and are cross-connected; The first hydraulic spring and the first accumulator are connected to the height adjustment valve block; the second hydraulic spring and the second accumulator are connected to the height adjustment valve block; wherein, the first hydraulic spring and the second hydraulic spring are used to perform the dynamic height adjustment hydraulic system operation and provide support for the frame; the first hydraulic spring and the second hydraulic spring are used to control the height of the frame, and the first accumulator and the second accumulator are used for buffering and shock absorption; The first port of the height adjustment valve block is connected to the hydraulic oil tank through the return oil filter and the return oil shut-off valve; The second port of the height adjustment valve block is connected to the hydraulic oil tank through the oil inlet shut-off valve, the check valve, and the motor pump; The height adjustment valve block is used to control the output or storage of hydraulic oil from the hydraulic oil tank to control the extension and retraction of the first and second hydraulic springs, so as to adjust the height of the vehicle frame. The system also includes a first locking valve block and a second locking valve block; The first hydraulic spring and the first accumulator are connected through the first locking valve block, which is used to control the first hydraulic spring and the first accumulator to be connected or isolated. The second hydraulic spring and the second accumulator are connected through the second locking valve block, which is used to control the connection or isolation between the second hydraulic spring and the second accumulator. If the vehicle corresponding to the hydraulic suspension system is in driving mode, the vehicle speed is greater than the first preset threshold and less than or equal to the second preset threshold, and the angle of the vehicle chassis and the turning angle of the vehicle's front wheels meet the preset angle conditions, then the height adjustment valve block is used to adjust the length of the first and second oil-gas springs according to the height of the vehicle frame. The height adjustment valve block includes: a pressure measuring connector, a plate-type shut-off valve, a solenoid directional valve, a balance valve, a hydraulic check valve, a proportional directional valve, a shuttle valve, a differential pressure reducing valve, and a pressure sensor. The pressure testing connector and the pressure sensor are used to measure the system pressure. The plate-type shut-off valve is used to provide a manual shut-off function; The electromagnetic reversing valve and the proportional directional valve work together to control the movement of the hydraulic suspension system; The proportional directional valve is also used to control the extension and retraction speeds of the first and second hydraulic springs. The balance valve is used to improve the stability of speed control when descending under heavy loads, and is also used in conjunction with the hydraulically controlled check valve to achieve less leakage when the hydraulic suspension system is not in operation; The shuttle valve is used to collect the load pressure of the hydraulic suspension system when the suspension is raised. The differential pressure reducing valve is used to control the stability of the pressure difference across the proportional directional valve.

2. The system according to claim 1, characterized in that, The first locking valve block and the second locking valve block are specifically used to control the chassis to adjust to a rigid locking mode and set the suspension to rigid if the vehicle corresponding to the hydraulic suspension system is in driving mode and the vehicle speed is less than or equal to a first preset threshold.

3. The system according to claim 2, characterized in that, The first locking valve block and the second locking valve block are specifically used to control the chassis to adjust to a rigid locking mode and set the suspension to rigid if the vehicle corresponding to the hydraulic suspension system is in driving mode and the vehicle speed is greater than a second preset threshold.

4. The system according to claim 1, characterized in that, If the height of the frame corresponding to one of the target sides of the chassis (left front, right front, left rear, right rear) is higher than the preset zero position, the height adjustment valve block is specifically used to adjust the length of the gas spring corresponding to the target side according to the height of the target side; if the height of the frame corresponding to one of the target sides of the chassis (left front, right front, left rear, right rear) is lower than the preset zero position, the height adjustment valve block is specifically used to adjust the length of the gas spring corresponding to the target side according to the height of the frame corresponding to the target side.

5. The system according to claim 4, characterized in that, If the height of the frame corresponding to at least a portion of the target sides of the chassis, including the left front, right front, left rear, and right rear sides, is not at the preset balance position, the height adjustment valve block is specifically used to adjust the length of the gas spring corresponding to the target side according to the height of the frame corresponding to the at least a portion of the target side and the preset balance position.

6. The system according to claim 1, characterized in that, The return oil filter is used to purify the hydraulic oil flowing back to the hydraulic oil tank; the return oil shut-off valve is used to control the opening and closing of the channel through which the hydraulic oil flows back to the hydraulic oil tank.

7. The system according to claim 1, characterized in that, The inlet shut-off valve is used to control the opening and closing of the channel through which hydraulic oil flows out of the hydraulic oil tank; the motor pump is used to output high-pressure oil; and the check valve is used to prevent high-pressure oil from flowing back to the motor pump.

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