Active hydraulic suspension liquid supply unit and control method

Abstract

The invention relates to the field of vehicle hydraulic suspensions, in particular to an active hydraulic suspension liquid supply unit and a control method thereof.Solenoid valves with relatively small sizes are integrated in a valve block to form an integrated liquid supply unit, and the integrated liquid supply unit comprises a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve and a one-way pump; the one-way pump is powered by a one-way motor, the first oil supply end of the first electromagnetic valve and the first oil supply end of the third electromagnetic valve are both communicated with a second liquid supply port of the active hydraulic suspension liquid supply unit, and the first oil supply end of the second electromagnetic valve and the first oil supply end of the fourth electromagnetic valve are both communicated with a first liquid supply port of the active hydraulic suspension liquid supply unit. The second oil feeding ends of the third electromagnetic valve and the fourth electromagnetic valve are communicated with the oil outlet end of the one-way pump, the second oil feeding ends of the first electromagnetic valve and the second electromagnetic valve are communicated with the oil inlet end of the one-way pump, control modes of different modes can be provided for a suspension according to different conditions, and therefore various defects of a suspension liquid supply system in the prior art are overcome.

Description

Technical Field

[0001] The invention relates to the field of vehicle hydraulic suspension, and in particular to an active hydraulic suspension fluid supply unit and a control method thereof. Background Art

[0002] Suspension is the general term for all the force-transmitting connection devices between the frame and wheels of a car. It is responsible for transmitting the force and torque acting between the wheels and the frame, and buffering the impact force transmitted to the frame or body by uneven roads, reducing the vibration caused thereby, so as to ensure that the car can run smoothly. Traditional suspension is passive suspension, and its stiffness and damping are fixed and cannot be adjusted during the driving process of the vehicle. It is currently mainly used in low-end models, while active suspension is mostly used in mid-to-high-end models, because the stiffness, height and damping of active suspension can be adjusted in real time during driving, so that the vehicle can run smoothly on roads of different conditions and has excellent driving performance.

[0003] Active hydraulic suspension is a commonly used structural form of active suspension. It is mainly composed of hydraulic shock absorbers, electric motors, hydraulic pumps, solenoid valves, control units and hydraulic pipelines. The motors used are divided into two types: unidirectional motors and bidirectional motors.

[0004] In the suspension system using a bidirectional hydraulic pump, a bidirectional internal gear pump is usually used as a bidirectional hydraulic pump to control the direction of the oil. However, since the bidirectional internal gear pump includes an internal gear, an external pinion, a crescent plate between the internal gear and the external pinion, a pump body, a transmission shaft, etc., the internal structure is complex. Therefore, the internal operating conditions of the bidirectional internal gear pump in the suspension system are more complicated, and higher standards in materials and processes are required to meet the durability requirements of this suspension system.

[0005] The bidirectional hydraulic pump uses a bidirectional motor as the power source, which drives the hydraulic pump to transport hydraulic oil in both directions, thereby realizing the dynamic adjustment of the suspension. Due to the defects of the bidirectional motor itself, this suspension system still has the following shortcomings:

[0006] ① The circuit of the suspension system is complex: When the suspension system is dynamically adjusted, the bidirectional motor changes the direction of rotation by changing the direction of the current through its control circuit. However, this control circuit alone cannot drive the bidirectional motor to operate normally, and various additional functional modules need to be set up, such as:

[0007] 1.1 Set up the drive circuit module so that the motor can obtain enough electrical energy to overcome the load resistance and drive the bidirectional motor to operate normally;

[0008] 1.2 Set up an overload protection module to prevent emergencies (such as overload, motor failure) from damaging the motor or even the entire control circuit.

[0009] Although the introduction of these additional functional modules ensures the normal operation of the bidirectional motor, it also greatly increases the circuit complexity of the entire suspension system and reduces the operating reliability of the suspension system;

[0010] ② The suspension system has great difficulty in controlling dynamic adjustment and has low control accuracy: In order to ensure that the vehicle can travel smoothly on different road surfaces, the commutation time of the bidirectional motor is often adjusted according to the current suspension load so that the hydraulic actuators (such as hydraulic cylinders and hydraulic motors) can smoothly transition when changing the direction of movement. However, when the bidirectional motor receives the commutation command from the suspension system and is ready to perform the commutation operation, the bidirectional motor is often affected by the rotational inertia due to the change in the direction of rotation of the motor. This rotational inertia will cause the bidirectional motor to continue to rotate in the current direction and speed for a period of time, prolonging the commutation time of the motor, resulting in reduced control accuracy and increased control difficulty for the entire suspension system for dynamic adjustment, which reduces the handling performance of the suspension system;

[0011] ③ The manufacturing technology threshold of the suspension system is high and the cost is high: the internal structure of the bidirectional motor contains a commutator, stator winding, rotor winding, and other auxiliary structures, and the internal structure is complex. During vehicle driving, the suspension load is dynamically changing and difficult to predict. The suspension system often frequently switches the working mode of the bidirectional motor to cope with these loads. However, frequent switching of working modes will accelerate the wear of the internal components of the bidirectional motor, so the suspension system can only use high-strength, high-hardness and good wear-resistant bidirectional motors, which increases the technical threshold and cost of manufacturing hydraulic suspensions.

[0012] In order to avoid these defects of the suspension system using a two-way hydraulic pump and make the suspension system suitable for a more demanding use environment, a one-way hydraulic pump is often used to construct the automobile suspension system. However, many new technical problems have arisen. For example, although the publication number CN116176198A "A Slow Active Hydraulic Suspension System Based on a Reversing Valve" can avoid the technical defects caused by the use of a two-way hydraulic pump, it still has the following disadvantages:

[0013] ① The unidirectional motor in the unidirectional hydraulic pump is multifunctional. It is responsible for driving the hydraulic pump to draw hydraulic oil from the oil tank and pressurize the hydraulic oil, and control the rise and fall of the shock absorber through the pressurized hydraulic oil; it is also responsible for driving the air compressor, and sucking in and compressing the outside air through the air compressor and delivering it to the air spring. This multifunctional design requires the internal mechanical parts of the unidirectional motor (such as bearings, rotors, stators, etc.) and various transmission parts connected to the outside (such as gears, belts, etc.) to frequently switch working modes according to different functional requirements, resulting in very complicated friction and wear between the various transmission parts, which accelerates the wear of the unidirectional motor and greatly shortens the service life of the unidirectional motor;

[0014] ② A large-volume two-position four-way solenoid reversing valve (such as a solenoid reversing valve with a length of 200mm, a width of 50mm, and a height of 85.5mm) is used in a one-way hydraulic pump to change the direction of the fluid flow. The two-position four-way solenoid reversing valve is mainly composed of a valve body, a valve core, an electromagnet, a spring and other components, and there are four oil ports on the valve body (respectively, an oil inlet, an oil return port, a working oil port A, and a working oil port B). The internal structure is complex, and the internal valve core has a large mass. When reversing, it will be affected by a large inertia and prolong the reversing time, making it impossible for the vehicle to quickly change direction under working conditions that require rapid reversing. In addition, the two-position four-way solenoid reversing valve also needs to be configured with a complex piping system, which makes the layout difficulty of the entire suspension system increase geometrically, greatly increasing the cost of the entire suspension system (including manufacturing cost and maintenance cost);

[0015] ③ The entire suspension system has no device to monitor the pipeline pressure, nor does it have a pressure-limiting safety valve to protect the hydraulic pump. When the vehicle encounters certain abnormal conditions (such as the vehicle is driving on an extremely bumpy road), the wheels will be frequently subjected to high-intensity impacts, and the suspension system will continuously compress the hydraulic oil in the pipeline to cope with these impacts, resulting in excessive pipeline pressure. The high pressure of this pipeline will directly act on the hydraulic pump and continue until the vehicle is no longer affected by this abnormal condition. This process is very likely to directly destroy the entire one-way hydraulic pump (including the motor), resulting in abnormal vehicle posture (such as obvious sinking or tilting) and steering difficulties (such as understeer or oversteer) when the vehicle is driving, which seriously affects the safety of the vehicle driving process;

[0016] ④ Use a hydraulic pump to separate the upper and lower chambers of the shock absorber. This structure allows the two ends of the pump to be directly connected to the upper and lower chambers of the shock absorber when the hydraulic pump is not working. Once the vehicle encounters a large impact (such as passing through an undulating road at high speed), the oil in the upper and lower chambers of the shock absorber will flow into the hydraulic pump in a very short time, causing the oil at both ends of the hydraulic pump to increase sharply, thereby causing a severe impact on the hydraulic pump, greatly reducing the service life of the hydraulic pump, and making it impossible for the hydraulic pump to maintain its working efficiency at a normal level. This structure will force the entire hydraulic system to have two accumulators to receive the hydraulic oil of the hydraulic system to avoid the hydraulic pump from suffering a reduction in life due to severe impact, greatly increasing the cost of the entire hydraulic suspension system.

[0017] How to avoid the technical defects of the suspension system using a two-way hydraulic pump, and how to avoid the technical defects of the current suspension system using a one-way hydraulic pump, so as to fundamentally improve the technology of the entire suspension system, has always been an urgent problem to be solved by those skilled in the art. Summary of the invention

[0018] The purpose of the present invention is to provide an active hydraulic suspension fluid supply unit and a control method to address the corresponding deficiencies in the prior art, integrate a relatively small solenoid valve into a valve block to form an integrated fluid supply unit, and cooperate with a unidirectional motor to provide different modes of control for the suspension in different situations, thereby avoiding the various defects of the suspension fluid supply system in the prior art.

[0019] The objective of the present invention is achieved by adopting the following scheme: an active hydraulic suspension fluid supply unit, comprising an integrated fluid supply unit, the integrated fluid supply unit is provided with a first fluid supply port and a second fluid supply port, which are used to respectively connect the two oil ports of the hydraulic shock absorber, the integrated fluid supply unit comprises a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve, and a one-way pump, the one-way pump is powered by a one-way motor, the first oil delivery ends of the first solenoid valve and the third solenoid valve are both connected to the second fluid supply port of the active hydraulic suspension fluid supply unit, the first oil delivery ends of the second solenoid valve and the fourth solenoid valve are both connected to the first fluid supply port of the active hydraulic suspension fluid supply unit, the second oil delivery ends of the third solenoid valve and the fourth solenoid valve are connected to the oil outlet end of the one-way pump, and the second oil delivery ends of the first solenoid valve and the second solenoid valve are connected to the oil inlet end of the one-way pump.

[0020] Preferably, it further comprises a valve block, the size of which is 80 mm×80 mm×40 mm, and the first solenoid valve, the second solenoid valve, the third solenoid valve and the fourth solenoid valve are integrated in the valve block.

[0021] Preferably, a pressure-limiting safety valve is further provided in the valve block, the oil inlet end of the pressure-limiting safety valve is communicated with the oil outlet end of the one-way pump, and the oil outlet end of the pressure-limiting safety valve is communicated with the oil inlet end of the one-way pump.

[0022] Preferably, the first solenoid valve, the second solenoid valve, the third solenoid valve and the fourth solenoid valve are all two-position two-way solenoid valves.

[0023] Preferably, it also includes a continuous damping control unit, which is provided with a first damping control port and a second damping control port, and the continuous damping control unit is arranged between the hydraulic shock absorber and the integrated fluid supply unit, so that the first damping control port and the second damping control port of the continuous damping control unit are respectively connected to the first fluid supply port and the second fluid supply port of the integrated fluid supply unit, so as to realize continuous damping control of the suspension.

[0024] Preferably, the continuous damping control unit includes a first solenoid proportional valve, a first damping valve, a first one-way valve, a second solenoid proportional valve, a second damping valve, a second one-way valve, and an accumulator, one end of the first solenoid proportional valve, the first damping valve, the first one-way valve, the second solenoid proportional valve, the second damping valve, and the second one-way valve are all connected to the accumulator, the other ends of the first solenoid proportional valve, the first damping valve, and the first one-way valve are all connected to the first damping control port of the continuous damping control unit, and the other ends of the second solenoid proportional valve, the second damping valve, and the second one-way valve are all connected to the second damping control port of the continuous damping control unit.

[0025] The method for controlling the suspension using the active hydraulic suspension fluid supply unit includes an active control mode, a semi-active continuous damping control mode, a passive damping control mode, and a suspension vibration frequency threshold is set to determine the timing of entering various modes:

[0026] When the real-time vibration frequency of the suspension is less than or equal to the suspension vibration frequency threshold, the active hydraulic suspension fluid supply unit controls the suspension in an active control mode;

[0027] When the real-time vibration frequency of the suspension is greater than the suspension vibration frequency threshold, the active hydraulic suspension fluid supply unit uses a semi-active continuous damping control mode to control the suspension;

[0028] When the active control mode and the semi-active continuous damping control mode fail, the active hydraulic suspension fluid supply unit uses the passive damping control mode to control the suspension.

[0029] Preferably, when the real-time vibration frequency of the suspension is less than or equal to the suspension vibration frequency threshold, the active hydraulic suspension fluid supply unit controls the suspension in an active control mode, and the specific steps include:

[0030] 1-1) Calculating the current target moving speed of the piston of the hydraulic shock absorber using the real-time signal of the vehicle, wherein the target moving speed includes a target rising speed or a target falling speed;

[0031] 1-2) Determine the type of target moving speed and control each valve in the following manner:

[0032] If the type of the target moving speed is the target ascending speed, the second solenoid valve and the third solenoid valve are opened, and the other valves are closed;

[0033] If the type of the target moving speed is the target descending speed, the first solenoid valve and the fourth solenoid valve are opened, and the other valves are closed;

[0034] 1-3) Utilizing the motor speed-piston target moving speed characteristic curve to obtain the motor target speed, and making the motor real-time speed equal to the motor target speed;

[0035] 1-4) Repeat steps 1-1) to 1-3), with the repetition frequency being equal to the real-time vibration frequency of the suspension.

[0036] Preferably, when the real-time vibration frequency of the suspension is greater than the suspension vibration frequency threshold, the active hydraulic suspension fluid supply unit controls the suspension using a semi-active continuous damping control mode, and the specific steps include:

[0037] 2-1) Turn off the one-way motor, the first solenoid valve, the second solenoid valve, the third solenoid valve, and the fourth solenoid valve;

[0038] 2-2) Using the real-time vehicle signal, calculate the current target piston movement speed of the hydraulic shock absorber and the target vertical force of the suspension;

[0039] 2-3) According to the target piston movement speed and the target suspension vertical force obtained in step 2-2), query the shock absorber damping characteristic curve diagram to obtain the current target openings of the first electromagnetic proportional valve and the second electromagnetic proportional valve, and make the real-time openings of the first electromagnetic proportional valve and the second electromagnetic proportional valve equal to the current target openings;

[0040] 2-4) Repeat steps 2-2) to 2-3) until the real-time vibration frequency of the suspension is no longer greater than the suspension vibration frequency threshold.

[0041] Preferably, when the active control mode and the semi-active continuous damping control mode fail, the unidirectional motor, the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, the first solenoid proportional valve and the second solenoid proportional valve are turned off, so that the active hydraulic suspension fluid supply unit adopts the passive damping control mode to control the suspension.

[0042] The beneficial effects of the present invention are as follows:

[0043] An active hydraulic suspension fluid supply unit includes an integrated fluid supply unit, the integrated fluid supply unit is provided with a first fluid supply port and a second fluid supply port, which are used to respectively connect the two oil ports of a hydraulic shock absorber, the integrated fluid supply unit includes a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve, and a one-way pump, the one-way pump is powered by a one-way motor, the first oil delivery ends of the first solenoid valve and the third solenoid valve are both connected to the second fluid supply port of the active hydraulic suspension fluid supply unit, the first oil delivery ends of the second solenoid valve and the fourth solenoid valve are both connected to the first fluid supply port of the active hydraulic suspension fluid supply unit, the second oil delivery ends of the third solenoid valve and the fourth solenoid valve are connected to the oil outlet end of the one-way pump, and the second oil delivery ends of the first solenoid valve and the second solenoid valve are connected to the oil inlet end of the one-way pump.

[0044] The fluid supply system of this structure has a simple oil circuit structure and a small oil transportation path within the system. Through the cooperation of various solenoid valves, the transportation state of the oil circuit can be quickly switched to cope with most working conditions that require rapid switching.

[0045] Preferably, a valve block is further included, the size of which is 80mm×80mm×40mm, and the first solenoid valve, the second solenoid valve, the third solenoid valve, and the fourth solenoid valve are integrated in the valve block. The first solenoid valve, the second solenoid valve, the third solenoid valve, and the fourth solenoid valve are all two-position two-way solenoid valves.

[0046] Since the two-position two-way solenoid valve is small in size and does not occupy too much internal space of the valve block, the oil passages connecting each solenoid valve with the outside can also be arranged inside the valve block, so that the entire valve block is fully functional but compact in size.

[0047] Preferably, a pressure-limiting safety valve is further provided in the valve block, the oil inlet end of the pressure-limiting safety valve is communicated with the oil outlet end of the one-way pump, and the oil outlet end of the pressure-limiting safety valve is communicated with the oil inlet end of the one-way pump.

[0048] That is to say, in order to ensure the normal and stable operation of the hydraulic system, a pressure-limiting safety valve is also provided in the valve block. When the vehicle hydraulic suspension system is abnormal, the internal pressure of the hydraulic circuit where the one-way pump is located rises rapidly and is greater than the set value, the pressure-limiting safety valve will open, and part of the oil of the one-way pump will flow from the oil outlet of the one-way pump to the oil inlet of the pressure-limiting safety valve, and then from the oil outlet of the pressure-limiting safety valve to the oil inlet of the one-way pump, forming a pipeline pressure relief circuit to reduce the excessive oil pressure in the pipeline and prevent high pressure from causing impact on the hydraulic pump.

[0049] Preferably, a continuous damping control unit is further included, the continuous damping control unit is provided with a first damping control port and a second damping control port, and the continuous damping control unit is arranged between the hydraulic shock absorber and the integrated liquid supply unit, so that the first damping control port and the second damping control port of the continuous damping control unit are respectively connected to the first liquid supply port and the second liquid supply port of the integrated liquid supply unit, so as to realize continuous damping control of the suspension. The continuous damping control unit includes a first electromagnetic proportional valve, a first damping valve, a first check valve, a second electromagnetic proportional valve, a second damping valve, a second check valve, and an accumulator, one end of the first electromagnetic proportional valve, the first damping valve, the first check valve, the second electromagnetic proportional valve, the second damping valve, and the second check valve are all connected to the accumulator, the other ends of the first electromagnetic proportional valve, the first damping valve, and the first check valve are all connected to the first damping control port of the continuous damping control unit, and the other ends of the second electromagnetic proportional valve, the second damping valve, and the second check valve are all connected to the second damping control port of the continuous damping control unit.

[0050] In this way, the present invention can control the suspension in a variety of different modes according to different situations. The method of controlling the suspension using the active hydraulic suspension fluid supply unit includes an active control mode, a semi-active continuous damping control mode, a passive damping control mode, and a suspension vibration frequency threshold is set to determine the timing of entering various modes:

[0051] 1) When the real-time vibration frequency of the suspension is less than or equal to the suspension vibration frequency threshold, the active hydraulic suspension fluid supply unit controls the suspension in an active control mode. The specific steps include:

[0052] 1-1) Calculating the current target moving speed of the piston of the hydraulic shock absorber using the real-time signal of the vehicle, wherein the target moving speed includes a target rising speed or a target falling speed;

[0053] 1-2) Determine the type of target moving speed and control each valve in the following manner:

[0054] If the target moving speed is the target ascending speed, the second solenoid valve and the third solenoid valve are opened, and the remaining valves are closed;

[0055] If the target moving speed is the target descending speed, the first solenoid valve and the fourth solenoid valve are opened, and the remaining valves are closed;

[0056] 1-3) Utilizing the motor speed-piston target moving speed characteristic curve to obtain the motor target speed, and making the motor real-time speed equal to the motor target speed;

[0057] 1-4) Repeat steps 1-1) to 1-3), with the repetition frequency being equal to the real-time vibration frequency of the suspension.

[0058] 2) When the real-time vibration frequency of the suspension is greater than the suspension vibration frequency threshold, the active hydraulic suspension fluid supply unit uses a semi-active continuous damping control mode to control the suspension. The specific steps include:

[0059] 2-1) Turn off the one-way motor, the first solenoid valve, the second solenoid valve, the third solenoid valve, and the fourth solenoid valve;

[0060] 2-2) Using the real-time vehicle signal, calculate the current target piston movement speed of the hydraulic shock absorber and the target vertical force of the suspension;

[0061] 2-3) According to the target piston movement speed and the target suspension vertical force obtained in step 2-2), query the shock absorber damping characteristic curve diagram to obtain the current target openings of the first electromagnetic proportional valve and the second electromagnetic proportional valve, and make the real-time openings of the first electromagnetic proportional valve and the second electromagnetic proportional valve equal to the current target openings;

[0062] 2-4) Repeat steps 2-2) to 2-3) until the real-time vibration frequency of the suspension is no longer greater than the suspension vibration frequency threshold.

[0063] 3) When the active control mode and the semi-active continuous damping control mode fail, the unidirectional motor, the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, the first solenoid proportional valve, and the second solenoid proportional valve are turned off, and the active hydraulic suspension fluid supply unit uses the passive damping control mode to control the suspension.

[0064] The advantages of the present invention are as follows:

[0065] ① The existing hydraulic system has a large motor rotation inertia, a complex oil circuit, a low switching limit frequency (usually only 5-6Hz), and a low active controllable frequency threshold. The oil circuit structure of the present invention is simple, the oil delivery path in the system is small, and the oil circuit delivery state can be quickly switched through the mutual cooperation of various solenoid valves (the mass of the valve core inside the reversing valve is not large, so it can), the switching frequency is high, and the active controllable frequency threshold is high (10-12Hz), which can cope with most working conditions that require rapid switching and can maximize the vehicle's handling stability and comfort performance.

[0066] ② The whole system of the present invention is simple in layout and low in cost. It uses a few simple solenoid valves to separate the hydraulic pump from the shock absorber, and these solenoid valves are used to resist the impact of the oil to protect the one-way pump. In other words, it can prevent the oil in the hydraulic shock absorber from being compressed sharply and causing impact on the one-way pump under large impact conditions, greatly improving the full life cycle (including service life) of the motor and hydraulic pump;

[0067] ③ The present invention adopts a unidirectional rotating motor, and the motor products and control technologies are very mature and have lower costs. The unidirectional hydraulic pump has low technical threshold and low cost, avoiding the problems of high technical threshold and high cost of components of the bidirectional hydraulic pump and great difficulty in controlling the bidirectional motor.

[0068] Glossary

[0069] Rotational inertia: It is the measure of the inertia of a rigid body when it rotates, and it is related to the mass distribution of the object and the position of the axis of rotation. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 It is a schematic diagram of the active hydraulic suspension fluid supply unit of the present invention, wherein: Figure 1 a is the schematic diagram of the hydraulic circuit of the active hydraulic suspension supply unit. Figure 1 b is a schematic structural diagram of the integrated liquid supply unit of the present invention;

[0071] Figure 2It is a schematic diagram of the oil direction when the type of the target moving speed is the target descending speed in the active control mode of the embodiment of the present invention;

[0072] Figure 3 It is a schematic diagram of the oil direction when the type of the target moving speed is the target rising speed in the active control mode of the embodiment of the present invention;

[0073] Figure 4 is a schematic diagram of a semi-active continuous damping control mode in an embodiment of the present invention;

[0074] Figure 5 is a schematic diagram of a passive damping control mode in an embodiment of the present invention;

[0075] Figure 6 Schematic diagram of pressure relief according to an embodiment of the present invention. DETAILED DESCRIPTION

[0076] like Figure 1 As shown, an active hydraulic suspension fluid supply unit includes an integrated fluid supply unit, the integrated fluid supply unit is provided with a first fluid supply port 26 and a second fluid supply port 27, which are used to respectively connect the two oil ports of the hydraulic shock absorber, the integrated fluid supply unit includes a first solenoid valve 4, a second solenoid valve 5, a third solenoid valve 6, a fourth solenoid valve 7, and a one-way pump 2, the one-way pump 2 is powered by a one-way motor 1, the first oil delivery ends of the first solenoid valve 4 and the third solenoid valve 6 are both connected to the second fluid supply port 27 of the active hydraulic suspension fluid supply unit, the first oil delivery ends of the second solenoid valve 5 and the fourth solenoid valve 7 are both connected to the first fluid supply port 26 of the active hydraulic suspension fluid supply unit, the second oil delivery ends of the third solenoid valve 6 and the fourth solenoid valve 7 are connected to the oil outlet end of the one-way pump 2, and the second oil delivery ends of the first solenoid valve 4 and the second solenoid valve 5 are connected to the oil inlet end of the one-way pump 2.

[0077] The fluid supply system of this structure not only has a simple oil circuit structure and a small oil delivery path in the system, but also can quickly switch the delivery state of the oil circuit through the cooperation of various solenoid valves to cope with most working conditions that require rapid reversal. In addition, the first solenoid valve 4, the second solenoid valve 5, the third solenoid valve 6, the fourth solenoid valve 7 and other solenoid valves are cleverly used to separate the hydraulic pump from the shock absorber, and these solenoid valves are used to resist the impact of the oil to protect the one-way pump 2. In other words, the vehicle can prevent the oil in the hydraulic shock absorber from being rapidly compressed and causing impact on the one-way pump 2 under large impact conditions.

[0078] In order to make the present invention have a faster response speed, and to be more flexibly arranged in the suspension system, and reduce the occupied space of the hydraulic system, a valve block 3 can also be provided, and four two-position two-way solenoid valves, such as the first solenoid valve 4, the second solenoid valve 5, the third solenoid valve 6, and the fourth solenoid valve 7, are integrated in the valve block (the size of the valve block 3 in this embodiment is 80mm×80mm×40mm). These two-position two-way solenoid valves are all cylindrical solenoid valves, the diameter of the cylindrical solenoid valve is 15mm, the height is 25mm, and the valve core volume of the cylindrical solenoid valve is very small. With the oil circuit design of the present invention, the direction of the medium in the oil circuit can be quickly converted (basically without delay), which can cope with most working conditions requiring rapid reversing.

[0079] In this embodiment, the lower end coils of the solenoid valves of the four two-position two-way solenoid valves, namely the first solenoid valve 4, the second solenoid valve 5, the third solenoid valve 6, and the fourth solenoid valve 7, are connected to the circuit board 8, and the upper ends of the solenoid valves are connected through the hydraulic pipeline in the valve block 3. The ECU exchanges signals with the circuit board (a protective shell 9 is also provided at the outer end of the circuit board) through the connector 10 to control the working state of the motor and the opening and closing of the first solenoid valve 4, the second solenoid valve 5, the third solenoid valve 6, the fourth solenoid valve 7, etc., so as to complete the control of the oil flow direction and flow size between the upper and lower chambers of the shock absorber.

[0080] In order to enable the present invention to adjust the stiffness, height and damping of the suspension in real time according to road conditions during vehicle driving, a continuous damping control unit is further arranged between the hydraulic shock absorber and the integrated liquid supply unit. The continuous damping control unit is provided with a first damping control port and a second damping control port, and the first damping control port and the second damping control port of the continuous damping control unit are respectively connected to the first liquid supply port 26 and the second liquid supply port 27 of the integrated liquid supply unit, so as to realize continuous damping control of the suspension.

[0081] In this embodiment, the continuous damping control unit includes a first electromagnetic proportional valve 13, a first damping valve 14, a first one-way valve 15, a second electromagnetic proportional valve 16, a second damping valve 17, a second one-way valve 18, and an accumulator 12, one end of the first electromagnetic proportional valve 13, the first damping valve 14, the first one-way valve 15, the second electromagnetic proportional valve 16, the second damping valve 17, and the second one-way valve 18 are all connected to the accumulator 12, the other end of the first electromagnetic proportional valve 13, the first damping valve 14, and the first one-way valve 15 are all connected to the first damping control port of the continuous damping control unit, and the other end of the second electromagnetic proportional valve 16, the second damping valve 17, and the second one-way valve 18 are all connected to the second damping control port of the continuous damping control unit.

[0082] In this embodiment, the hydraulic shock absorber includes a shock absorber cylinder 19, a one-way valve 20, a shock absorber piston 21, a shock absorber piston rod 22, an air spring 23, a buffer block 24, and a shock absorber top mounting bushing 25. The upper and lower chambers of the hydraulic shock absorber are connected after passing through respective damping valves, and only one accumulator 12 is required for buffering and shock absorption, which can save costs.

[0083] In this way, the present invention can control the suspension in the following different modes according to different situations. In this embodiment, the hydraulic suspension system of the vehicle has three control modes: active control mode, semi-active continuous damping control mode, passive damping control mode, and the suspension vibration frequency threshold is set to 10Hz to determine the timing of entering various modes:

[0084] 1) The active control mode is as follows Figure 2-3 As shown, when the real-time vibration frequency of the suspension is ≤10Hz, the active hydraulic suspension supply unit uses the active control mode to control the suspension. The specific steps include:

[0085] 1-1) Calculating the current target moving speed of the piston of the hydraulic shock absorber using the real-time signal of the vehicle, wherein the target moving speed includes a target rising speed or a target falling speed;

[0086] 1-2) Determine the type of target moving speed and control each valve in the following manner:

[0087] If the type of the target moving speed is the target ascending speed, the second solenoid valve 5 and the third solenoid valve 6 are opened, and the other valves are closed;

[0088] If the type of the target moving speed is the target descending speed, the first solenoid valve 4 and the fourth solenoid valve 7 are opened, and the other valves are in the closed state;

[0089] 1-3) Utilizing the motor speed-piston target moving speed characteristic curve to obtain the motor target speed, and making the motor real-time speed equal to the motor target speed;

[0090] 1-4) Repeat steps 1-1) to 1-3), with the repetition frequency being equal to the real-time vibration frequency of the suspension.

[0091] The motor speed-piston target moving speed characteristic curve in this embodiment is a two-dimensional curve used to reflect the relationship between the motor speed and the shock absorber piston moving speed, and can usually be obtained from a prior calibration test.

[0092] 2) The semi-active continuous damping control mode is as follows Figure 4 As shown, when the real-time vibration frequency of the suspension is greater than 10 Hz, the active hydraulic suspension fluid supply unit uses a semi-active continuous damping control mode to control the suspension. The specific steps include:

[0093] 2-1) Close the one-way motor 1, the first solenoid valve 4, the second solenoid valve 5, the third solenoid valve 6, and the fourth solenoid valve 7;

[0094] 2-2) Using the real-time vehicle signal, calculate the current target piston movement speed of the hydraulic shock absorber and the target vertical force of the suspension;

[0095] 2-3) According to the target piston moving speed and the target suspension vertical force obtained in step 2-2), the shock absorber damping characteristic curve is queried to obtain the current target openings of the first electromagnetic proportional valve 13 and the second electromagnetic proportional valve 16, and the real-time openings of the first electromagnetic proportional valve 13 and the second electromagnetic proportional valve 16 are made equal to the current target openings;

[0096] It is worth noting that the shock absorber damping characteristic curve diagram is actually a two-dimensional plane coordinate system with multiple relationship curves between the vertical force of the suspension and the piston movement speed. Each relationship curve corresponds to an opening of the electromagnetic proportional valve. This shock absorber damping characteristic curve diagram is obtained through prior calibration experiments.

[0097] 2-4) Repeat steps 2-2) to 2-3) until the real-time vibration frequency of the suspension is no longer greater than the suspension vibration frequency threshold.

[0098] 3) The passive damping control mode is as follows Figure 5 As shown, when the active control mode and the semi-active continuous damping control mode fail, the unidirectional motor 1, the first solenoid valve 4, the second solenoid valve 5, the third solenoid valve 6, the fourth solenoid valve 7, the first solenoid proportional valve 13, and the second solenoid proportional valve 16 are closed, so that the active hydraulic suspension fluid supply unit adopts the passive damping control mode to control the suspension.

[0099] In this embodiment, in order to ensure the normal and stable operation of the hydraulic system, a pressure-limiting safety valve 11 is further provided in the valve block, and the oil inlet end of the pressure-limiting safety valve is connected to the oil outlet end of the one-way pump, and the oil outlet end of the pressure-limiting safety valve is connected to the oil inlet end of the one-way pump. When an abnormality occurs in the vehicle hydraulic suspension system, the internal pressure of the hydraulic circuit where the one-way pump 2 is located rises rapidly and is greater than the set value, the pressure-limiting safety valve 11 opens, and part of the oil of the one-way pump 2 flows from the oil outlet end of the one-way pump 2 to the oil inlet end of the pressure-limiting safety valve 11, and then flows from the oil outlet end of the pressure-limiting safety valve 11 to the oil inlet end of the one-way pump 2, forming a pipeline pressure relief circuit to reduce the excessive oil pressure in the pipeline and prevent the excessive oil pressure from causing impact on the hydraulic pump, such as Figure 6 shown.

[0100] Comparative experiments have shown that the present invention increases the selection range of hydraulic suspension parts and reduces the cost of hydraulic suspension integrated units while ensuring that the vehicle can travel smoothly under different road conditions. For example, the overall cost of a suspension fluid supply system (including motor + hydraulic pump + circuit board) made with a bidirectional motor is usually between 2,000 and 3,000 yuan, and the overall cost of a suspension fluid supply system (including motor + hydraulic pump + circuit board) made with a unidirectional motor is usually between 1,500 and 2,000 yuan. By adopting the structural design of the present invention, the overall cost of the suspension fluid supply system (motor + hydraulic pump + circuit board) can be reduced to only between 800 and 1,200 yuan, greatly improving the development and application space of automobile suspension hydraulic control systems.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. An active hydraulic suspension fluid supply unit, characterized in that: The invention comprises an integrated liquid supply unit, wherein the integrated liquid supply unit is provided with a first liquid supply port (26) and a second liquid supply port (27) for respectively connecting two oil ports of a hydraulic shock absorber. The integrated liquid supply unit comprises a first solenoid valve (4), a second solenoid valve (5), a third solenoid valve (6), a fourth solenoid valve (7), and a one-way pump (2). The one-way pump (2) is powered by a one-way motor (1). The first oil supply ends of the first solenoid valve (4) and the third solenoid valve (6) are both connected to the second liquid supply port (27) of the active hydraulic suspension liquid supply unit. The first oil supply ends of the second solenoid valve (5) and the fourth solenoid valve (7) are both connected to the first liquid supply port (26) of the active hydraulic suspension liquid supply unit. The second oil supply ends of the third solenoid valve (6) and the fourth solenoid valve (7) are connected to the oil outlet end of the one-way pump (2). The second oil supply ends of the first solenoid valve (4) and the second solenoid valve (5) are connected to the oil inlet end of the one-way pump (2).

2. The active hydraulic suspension fluid supply unit according to claim 1, characterized in that: It also comprises a valve block (3) having a size of 80 mm×80 mm×40 mm, wherein the first solenoid valve (4), the second solenoid valve (5), the third solenoid valve (6) and the fourth solenoid valve (7) are integrated in the valve block.

3. The active hydraulic suspension fluid supply unit according to claim 2, characterized in that: The valve block (3) is also provided with a pressure-limiting safety valve (11), the oil inlet end of the pressure-limiting safety valve (11) is connected to the oil outlet end of the one-way pump (2), and the oil outlet end of the pressure-limiting safety valve (11) is connected to the oil inlet end of the one-way pump (2).

4. An active hydraulic suspension fluid supply unit according to claim 1 or 2, characterized in that: The first solenoid valve (4), the second solenoid valve (5), the third solenoid valve (6) and the fourth solenoid valve (7) are all two-position two-way solenoid valves.

5. The active hydraulic suspension fluid supply unit according to claim 1, characterized in that: The invention also comprises a continuous damping control unit, which is provided with a first damping control port and a second damping control port, and the continuous damping control unit is arranged between the hydraulic shock absorber and the integrated liquid supply unit, so that the first damping control port and the second damping control port of the continuous damping control unit are respectively connected with the first liquid supply port (26) and the second liquid supply port (27) of the integrated liquid supply unit, so as to realize continuous damping control of the suspension.

6. The active hydraulic suspension fluid supply unit according to claim 5, characterized in that: The continuous damping control unit comprises a first electromagnetic proportional valve (13), a first damping valve (14), a first non-return valve (15), a second electromagnetic proportional valve (16), a second damping valve (17), a second non-return valve (18), and an accumulator (12); one end of the first electromagnetic proportional valve (13), the first damping valve (14), the first non-return valve (15), the second electromagnetic proportional valve (16), the second damping valve (17), and the second non-return valve (18) are all connected to the accumulator (12); the other ends of the first electromagnetic proportional valve (13), the first damping valve (14), and the first non-return valve (15) are all connected to a first damping control port of the continuous damping control unit; and the other ends of the second electromagnetic proportional valve (16), the second damping valve (17), and the second non-return valve (18) are all connected to a second damping control port of the continuous damping control unit.

7. A method for controlling a suspension using the active hydraulic suspension fluid supply unit of claim 1, characterized in that: It includes active control mode, semi-active continuous damping control mode, passive damping control mode, and sets a suspension vibration frequency threshold to determine the timing of entering various modes: When the real-time vibration frequency of the suspension is less than or equal to the suspension vibration frequency threshold, the active hydraulic suspension fluid supply unit controls the suspension in an active control mode; When the real-time vibration frequency of the suspension is greater than the suspension vibration frequency threshold, the active hydraulic suspension fluid supply unit uses a semi-active continuous damping control mode to control the suspension; When the active control mode and the semi-active continuous damping control mode fail, the active hydraulic suspension fluid supply unit uses the passive damping control mode to control the suspension.

8. A method for controlling a suspension using the active hydraulic suspension fluid supply unit of claim 7, characterized in that: When the real-time vibration frequency of the suspension is less than or equal to the suspension vibration frequency threshold, the active hydraulic suspension fluid supply unit uses the active control mode to control the suspension. The specific steps include: 1-1) Calculating the current target moving speed of the piston of the hydraulic shock absorber using the real-time signal of the vehicle, wherein the target moving speed includes a target rising speed or a target falling speed; 1-2) Determine the type of target moving speed and control each valve in the following manner: If the type of the target moving speed is the target ascending speed, the second solenoid valve (5) and the third solenoid valve (6) are opened, and the remaining valves are all in a closed state; If the type of the target moving speed is the target descending speed, the first solenoid valve (4) and the fourth solenoid valve (7) are opened, and the remaining valves are all in a closed state; 1-3) Utilizing the motor speed-piston target moving speed characteristic curve to obtain the motor target speed, and making the motor real-time speed equal to the motor target speed; 1-4) Repeat steps 1-1) to 1-3), with the repetition frequency being equal to the real-time vibration frequency of the suspension.

9. A method for controlling a suspension using the active hydraulic suspension fluid supply unit of claim 7, characterized in that: When the real-time vibration frequency of the suspension is greater than the suspension vibration frequency threshold, the active hydraulic suspension fluid supply unit uses a semi-active continuous damping control mode to control the suspension. The specific steps include: 2-1) closing the one-way motor (1), the first solenoid valve (4), the second solenoid valve (5), the third solenoid valve (6), and the fourth solenoid valve (7); 2-2) Using the real-time vehicle signal, calculate the current target piston movement speed of the hydraulic shock absorber and the target vertical force of the suspension; 2-3) According to the target piston movement speed and the target vertical force of the suspension obtained in step 2-2), the damping characteristic curve of the shock absorber is queried to obtain the current target openings of the first electromagnetic proportional valve (13) and the second electromagnetic proportional valve (16), and the real-time openings of the first electromagnetic proportional valve (13) and the second electromagnetic proportional valve (16) are made equal to the current target openings; 2-4) Repeat steps 2-2) to 2-3) until the real-time vibration frequency of the suspension is no longer greater than the suspension vibration frequency threshold.

10. A method for controlling a suspension using the active hydraulic suspension fluid supply unit of claim 7, characterized in that: When the active control mode and the semi-active continuous damping control mode fail, the one-way motor (1), the first solenoid valve (4), the second solenoid valve (5), the third solenoid valve (6), the fourth solenoid valve (7), the first solenoid proportional valve (13), and the second solenoid proportional valve (16) are turned off, so that the active hydraulic suspension fluid supply unit adopts the passive damping control mode to control the suspension.

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