Hydrocarbon suspension system, vehicle and control method

Abstract

This invention relates to the field of suspension system technology, specifically to a hydropneumatic suspension system, a vehicle, and a control method. The suspension system includes a suspension cylinder, a main directional valve, a first suspension valve assembly, and a second suspension valve assembly. The first end of the main directional valve is connected to the rodless chamber of the suspension cylinder. Port A1 of the first suspension valve assembly is connected to the second end of the main directional valve; ports A2 and A3 are respectively connected to the rodless and rod chambers of the suspension cylinder; port SP is connected to a first accumulator. Port P of the second suspension valve assembly is connected to a hydraulic pump; ports T1 and T2 are both connected to a hydraulic oil tank; ports A1 and B1 are respectively connected to the rodless and rod chambers of the suspension cylinder; port A2 is connected to the second end of the main directional valve and is connected in parallel with port A1 of the first suspension valve assembly; port B2 is connected to the rod chamber of the suspension cylinder; port SP is connected to port A2 and is linked to a second accumulator. By controlling the main directional valve, the first suspension valve assembly, and the second suspension valve assembly, the suspension can be adaptively adjusted according to the vehicle's driving conditions to improve ride comfort.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of suspension systems, in particular to an oil-gas suspension system, a vehicle and a control method. BACKGROUND

[0002] The oil-gas suspension system is a suspension system frequently configured for a wheel crane, especially an all-terrain crane. The basic component elements include a suspension cylinder, an accumulator and a control valve. The upper end of the suspension cylinder is connected to a spring-on support such as a vehicle frame or a crane arm, and the lower end is connected to an axle. The suspension cylinder is usually a double-acting cylinder, including a rodless cavity and a rod cavity. For the oil-gas suspension system, road excitation is transmitted to the suspension cylinder through the axle, pushing the suspension cylinder to extend and retract. The oil in the suspension cylinder and the accumulator interact rapidly and frequently. The interaction process needs to have a suitable damping state. The damping is needed to reduce the vibration caused by road excitation, and the damping is also needed to avoid excessive dynamic stiffness caused by excessive damping, thereby reducing comfort.

[0003] At present, the all-terrain crane usually adopts a passive oil-gas suspension. The inherent stiffness and damping of the suspension are single and unadjustable. Only under a specific axle load, the ideal vibration reduction performance and control performance can be obtained. The ride comfort and the steering stability under various axle loads of the vehicle cannot be considered.

[0004] The prior art needs a suspension system which can adaptively adjust the suspension stiffness and damping according to the vehicle driving conditions to simultaneously improve the ride comfort and the steering stability of the vehicle. SUMMARY

[0005] The purpose of the present application is to provide an oil-gas suspension system, a vehicle and a control method. By controlling the main reversing valve, the first suspension valve group and the second suspension valve group, the suspension stiffness and damping can be adaptively adjusted according to the vehicle driving conditions to simultaneously improve the ride comfort and the steering stability of the vehicle.

[0006] In a first aspect, the present application provides an oil-gas suspension system, comprising:

[0007] a suspension cylinder,

[0008] a main reversing valve, a first end of which is connected to a rodless cavity of the suspension cylinder;

[0009] a first suspension valve group, an A1 port of which is connected to a second end of the main reversing valve, an A2 port and an A3 port of which are respectively connected to the rodless cavity and the rod cavity of the suspension cylinder, and an SP port of which is connected to a first accumulator; the first suspension valve group comprises a first reversing valve, a second reversing valve and a third reversing valve, a first end of the first reversing valve is connected to the A3 port, a second end of the first reversing valve is connected in parallel to the A2 port and a first end of the third reversing valve; a first end of the second reversing valve is connected to the A1 port, a second end of the second reversing valve is connected in parallel to the SP port and a second end of the third reversing valve;

[0010] The second suspension valve group is connected with the hydraulic oil pump at the P port, connected with the hydraulic oil tank at the T1 port and the T2 port, connected with the rodless cavity and the rod cavity of the suspension oil cylinder at the A1 port and the B1 port respectively, connected with the second end of the main reversing valve at the A2 port and connected with the A1 port of the first suspension valve group in parallel, connected with the rod cavity of the suspension oil cylinder at the B2 port, and connected with the A2 port and provided with the second accumulator at the SP port. The sixth reversing valve is arranged between the B2 port and the T2 port of the second suspension valve group.

[0011] The main reversing valve, the first reversing valve, the second reversing valve, the third reversing valve and the sixth reversing valve all have a through position and a cut-off position.

[0012] Optionally, the first suspension valve group further comprises:

[0013] The first damping hole is arranged between the A1 port of the first suspension valve group and the first end of the second reversing valve.

[0014] The second damping hole is connected with the second end of the second reversing valve and the second end of the third reversing valve at the first end in parallel, and connected with the SP port of the first suspension valve group at the second end.

[0015] The first check valve is connected with the first end of the second damping hole at the oil inlet, and connected with the second end of the second damping hole at the oil outlet.

[0016] Optionally, the second suspension valve group further comprises:

[0017] The second overflow valve is connected with the B2 port of the second suspension valve group at the oil inlet and located downstream of the sixth reversing valve, and connected with the T2 port of the second suspension valve group at the oil outlet.

[0018] The third overflow valve is connected with the A2 port and the SP port of the second suspension valve group at the oil inlet in parallel through the third damping hole, and connected with the T2 port of the second suspension valve group at the oil outlet.

[0019] Optionally, further comprising:

[0020] The first electrically controlled gas reversing valve is arranged between the first gas source and the first control port of the main reversing valve. When the first electrically controlled gas reversing valve is electrified and through, the first gas source can output high-pressure gas to act on the first control port of the main reversing valve to switch the main reversing valve to the cut-off position.

[0021] The second electrically controlled gas reversing valve is arranged between the second gas source and the second control port of the main reversing valve. When the second electrically controlled gas reversing valve is electrified and through, the second gas source can output high-pressure gas to act on the second control port of the main reversing valve to switch the main reversing valve to the through position.

[0022] Optionally, the first reversing valve, the second reversing valve, the third reversing valve of the first suspension valve group and the sixth reversing valve of the second suspension valve group are all electromagnetic reversing valves, and are switched from the cut-off position to the through position when electrified.

[0023] Optionally, the second suspension valve assembly also includes:

[0024] The fifth directional valve has its inlet, outlet, first working port, and second working port connected to the P port, T1 port, A1 port, and B1 port of the second suspension valve assembly, respectively.

[0025] A hydraulic two-way lock is located between port A1 and port B1 of the fifth directional valve and the second suspension valve assembly;

[0026] The second check valve is located between the return port of the fifth directional valve and the T1 port of the second suspension valve assembly.

[0027] The fifth directional valve is connected to a first solenoid valve and a second solenoid valve.

[0028] When the first solenoid valve is energized, the fifth directional valve is in the left position, and the oil inlet of the fifth directional valve is connected to the first working oil port, and the second working oil port is connected to the return oil port.

[0029] When the second solenoid valve is energized, the fifth directional valve is in the right position, and the oil inlet and the second working oil port of the fifth directional valve are connected, and the first working oil port and the return oil port are connected.

[0030] When neither the first nor the second solenoid valve is energized, the fifth directional valve is in the neutral position, the oil inlet of the fifth directional valve is closed, and both the first and second working oil ports are connected to the return oil port.

[0031] Optionally, the second suspension valve assembly further includes:

[0032] The eleventh directional valve has its first end connected in parallel to port B2 of the second suspension valve assembly and one end of port B2 of the sixth directional valve assembly, and its second end connected in parallel to port SP and port A2 of the second suspension valve assembly.

[0033] Optionally, it includes:

[0034] The first relief valve has its inlet connected to the outlet of the hydraulic oil pump, and its outlet connected to the hydraulic oil tank.

[0035] Optionally, it also includes:

[0036] The third accumulator is connected to the rodless chamber of the suspension cylinder via the twelfth directional valve; the twelfth directional valve has a through position and a cut-off position;

[0037] The fourth directional valve controls the valve position of the twelfth directional valve.

[0038] The air inlet of the fourth reversing valve is connected to the third air source, and the first air outlet and the second air outlet are respectively connected to the first control port and the second control port of the twelfth reversing valve.

[0039] When the left solenoid valve of the fourth reversing valve is energized, the fourth reversing valve is in the left position, the air inlet and the first air outlet are connected, the third air source can output high pressure gas through the fourth reversing valve to act on the first control port of the twelfth reversing valve, the twelfth reversing valve switches to the through position, and the third accumulator is connected to the rodless chamber of the suspension cylinder through the twelfth reversing valve.

[0040] When the right solenoid valve of the fourth reversing valve is energized, the fourth reversing valve is in the right position, the air inlet and the second air outlet are connected, and the third air source can output high-pressure gas through the fourth reversing valve to act on the second control port of the twelfth reversing valve. The twelfth reversing valve switches to the cut-off position, and the third accumulator is disconnected from the rodless chamber of the suspension cylinder.

[0041] When neither the left nor the right solenoid valve of the fourth reversing valve is energized, the fourth reversing valve is in the neutral position and the air inlet is cut off.

[0042] Optionally, the second suspension valve assembly also includes:

[0043] The ninth directional valve is located between the P port and the A1 port of the second suspension valve assembly;

[0044] The tenth directional valve is located between port B1 and port T1 of the second suspension valve assembly;

[0045] Both the ninth and tenth directional valves are electromagnetic directional valves, which switch from the cut-off position to the through position when energized.

[0046] Optionally, the second suspension valve assembly also includes:

[0047] The third check valve and the seventh directional valve, wherein the oil inlet of the third check valve is connected to the P port of the second suspension valve group, the oil outlet of the third check valve is connected to the oil inlet of the seventh directional valve, and the oil outlet of the seventh directional valve is connected to the A1 port of the second suspension valve group.

[0048] The fourth check valve and the eighth directional valve, wherein the oil inlet of the eighth directional valve is connected to the B1 port of the second suspension valve group, the oil outlet is connected to the oil inlet of the fourth check valve, and the oil outlet of the fourth check valve is connected to the T1 port of the second suspension valve group.

[0049] Both the seventh and eighth directional valves are electromagnetic directional valves, which switch from the cut-off position to the through position when energized.

[0050] Secondly, the present invention provides a vehicle in which the aforementioned air-hydraulic suspension system is provided at the front left, rear left, front right, and rear right positions, and the outlet of the hydraulic oil pump is connected in parallel with the P port of the second suspension valve group of the air-hydraulic suspension system at each position.

[0051] Thirdly, the present invention provides a vehicle control method based on the vehicle, the control method comprising:

[0052] When the vehicle is moving and not steering or braking, for the hydropneumatic suspension system in each direction of the vehicle:

[0053] Keep ports A1 and B1 of the second suspension valve group closed, use a pressure sensor to obtain the working pressure of the rodless chamber of the suspension cylinder, and calculate the actual axle load by multiplying the working pressure of the rodless chamber of the suspension cylinder by the piston area.

[0054] When the actual axle load is less than or equal to the first axle load, the main directional valve and the first directional valve of the first suspension valve group are in the through position, and the second directional valve, the third directional valve, and the sixth directional valve of the first suspension valve group are all in the cut-off position.

[0055] When the actual axle load is greater than the first axle load and less than or equal to the second axle load, the sixth directional valve of the main directional valve and the second suspension valve group is placed in the through position, and the first directional valve, the second directional valve and the third directional valve of the first suspension valve group are all placed in the cut-off position.

[0056] When the actual axle load is greater than the second axle load, the main directional valve, the second and third directional valves of the first suspension valve group, and the sixth directional valve of the second suspension valve group are all in the through position, and the first directional valve of the first suspension valve group is in the cut-off position.

[0057] Optionally, when the vehicle is moving and braking, if the actual axle load of the left front and right front hydraulic suspension systems is greater than the second axle load, the hydraulic suspension system with the actual axle load greater than the second axle load is identified as the target braking suspension system.

[0058] For the braking target suspension system, when the vehicle is braking, the second and third directional valves of the first suspension valve group are switched from the open position to the closed position. When the brake is released, the second directional valve is first switched from the closed position to the open position, and after a preset time delay, the third directional valve is switched from the closed position to the open position.

[0059] Optionally, when the vehicle is driving and turning, if the actual axle load of the hydropneumatic suspension system located on the opposite side of the turning direction is greater than the second axle load, the hydropneumatic suspension system with the actual axle load greater than the second axle load shall be identified as the target steering suspension system.

[0060] For the steering target suspension system, when the vehicle is turning, the second and third directional valves of the first suspension valve group are switched from the open position to the closed position. When the turning ends, the second directional valve is switched from the closed position to the open position first, and after a preset time delay, the third directional valve is switched from the closed position to the open position.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] The suspension stiffness and damping of the hydropneumatic suspension system of the present invention can be adaptively adjusted according to the vehicle driving conditions. The present invention uses the actual axle load obtained by multiplying the working pressure of the rodless chamber of the suspension cylinder and the piston area to distinguish different vehicle driving conditions and adjust the suspension stiffness and damping accordingly.

[0063] When the actual axle load is less than or equal to the first axle load, the main directional valve and the first directional valve of the first suspension valve group are in the through position, while the second and third directional valves of the first suspension valve group and the sixth directional valve of the second suspension valve group are all in the cut-off position. In this state, the rodless chamber of the suspension cylinder is connected to the second accumulator via the main directional valve and the A2 and SP ports of the second suspension valve group. This effectively increases the working pressure of the suspension system under light axle load conditions. The second accumulator can replenish the oil needed by the rodless chamber when the suspension cylinder extends during vehicle operation, increasing the stroke of the suspension cylinder and improving the suspension's contact performance. At the same time, when the suspension cylinder compresses during vehicle operation, the rodless and rod chambers of the suspension cylinder are connected via the A3 port of the first suspension valve group, the first directional valve, and the A2 port of the first suspension valve group to form a differential cylinder. This reduces the hydraulic oil exchange flow between the suspension cylinder and the second accumulator, thereby reducing suspension damping and improving vehicle ride comfort.

[0064] When the actual axle load is greater than the first axle load but less than or equal to the second axle load, the main directional valve and the sixth directional valve of the second suspension valve group are in the through position, while the first, second, and third directional valves of the first suspension valve group are all in the cut-off position. In this state, the rod chamber of the suspension cylinder is connected to the hydraulic oil tank through port B2 of the second suspension valve group, port T2 of the sixth directional valve and the second suspension valve group, and the rodless chamber of the suspension cylinder is connected to the second accumulator through the main directional valve, port A2 of the second suspension valve group, and port SP. In this state, the sprung weight of the suspension only builds pressure in the rodless chamber of the suspension cylinder. Compared with the prior art where the sprung weight of the suspension builds pressure in both the rodless and rod chambers of the suspension cylinder, this state can effectively reduce the cylinder diameter, rod diameter, and weight of the suspension cylinder while maintaining consistent working pressure of the suspension system, and further reduce the hydraulic oil interaction flow between the rodless chamber of the suspension cylinder and the second accumulator, thereby reducing suspension damping and improving vehicle ride comfort.

[0065] When the actual axle load is greater than the second axle load, the main directional valve, the second and third directional valves of the first suspension valve group, and the sixth directional valve of the second suspension valve group are in the through position, and the first directional valve of the first suspension valve group is in the cut-off position. In this state, the rod chamber of the suspension cylinder is connected to the hydraulic oil tank through the B2 port of the second suspension valve group, the sixth directional valve, and the T2 port of the second suspension valve group. The rodless chamber of the suspension cylinder is connected to the second accumulator through the main directional valve, the A2 port of the second suspension valve group, and the SP port. The rodless chamber of the suspension cylinder is also connected to the first accumulator through the parallel first oil circuit (passing sequentially through the main directional valve, the A1 port of the first suspension valve group, the second directional valve, and the SP port of the first suspension valve group) and the second oil circuit (passing sequentially through the A2 port of the first suspension valve group, the third directional valve, and the SP port of the first suspension valve group). In this state, the suspension spring weight also only builds pressure in the rodless chamber of the suspension cylinder. The rodless chamber of the suspension cylinder is simultaneously connected to the first accumulator and the second accumulator. This state reduces the stiffness of the suspension system by increasing the effective volume of the accumulator, thereby improving the ride comfort of the vehicle. Attached Figure Description

[0066] Figure 1 Hydraulic schematic diagram of the hydropneumatic suspension system provided in the embodiments of the present invention;

[0067] Figure 2 for Figure 1 Hydraulic schematic diagram of the first suspension valve group;

[0068] Figure 3 for Figure 1 Hydraulic schematic diagram of the second suspension valve group;

[0069] Figure 4 Hydraulic schematic diagram of the chassis suspension system of a five-axle crane used in the oil-gas suspension system provided in this embodiment of the invention;

[0070] Figure 5 for Figure 1 Hydraulic schematic diagram of an optional embodiment of the second suspension valve assembly;

[0071] Figure 6 for Figure 1 Hydraulic schematic diagram of another alternative embodiment of the second suspension valve assembly;

[0072] Figure 7 for Figure 1 Hydraulic schematic diagram of another alternative embodiment of the second suspension valve group.

[0073] The following are the valve numbers in the diagram: 1. Second suspension valve assembly; 101. Fifth directional valve; 102. Hydraulic two-way lock; 103. Sixth directional valve; 104. Second relief valve; 105. Third relief valve; 106. Third damping orifice; 107. Second check valve; 108. Eleventh directional valve; 109. Seventh directional valve; 1010. Third check valve; 1011. Ninth directional valve; 1012. Tenth directional valve; 1013. Eighth directional valve; 1014. Fourth check valve; 2. Suspension cylinder; 3. Main directional valve; 4. Second accumulator; 5. Hydraulic oil pump; 6. Hydraulic oil tank; 7. First relief valve; 8. First electro-pneumatic directional valve; 9. Second electro-pneumatic directional valve; 10. Fourth directional valve; 11. First suspension valve assembly; 1101. First directional valve; 1102. First damping orifice; 1103. Second directional valve; 1104. First check valve; 1105. Second damping orifice; 1106. Third directional valve; 12. First accumulator; 13. Pressure sensor; 14. Third accumulator; 15. Twelfth directional valve. Detailed Implementation

[0074] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0075] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0076] To make the purpose, technical solution, and advantages of this invention patent clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0077] Combination Figure 1 This embodiment provides an oil-pneumatic suspension system, which includes a suspension cylinder 2, a pressure sensor 13, a main directional valve 3, a first suspension valve group 11, and a second suspension valve group 1. The pressure sensor 13 is connected to the rodless chamber of the suspension cylinder 2 to detect the working pressure of the rodless chamber of the suspension cylinder 2. The first end of the main directional valve 3 is connected to the rodless chamber of the suspension cylinder 2, and the second end is connected in parallel to the A1 port of the first suspension valve group 11 and the A2 port of the second suspension valve group 1.

[0078] In this embodiment, the main directional valve 3 is a pneumatic-controlled hydraulic directional valve. The control air source is generated by an air compressor driven by the vehicle engine and works in conjunction with the first electro-pneumatic directional valve 8 and the second electro-pneumatic directional valve 9 to achieve the switching of the main directional valve 3. The first electro-pneumatic directional valve 8 is located between the first air source and the first control port of the main directional valve 3. When the first electro-pneumatic directional valve 8 is energized and open, the first air source can output high-pressure gas to act on the first control port of the main directional valve 3, causing the main directional valve 3 to switch to the off position. The second electro-pneumatic directional valve 9 is located between the second air source and the second control port of the main directional valve 3. When the second electro-pneumatic directional valve 9 is energized and open, the second air source can output high-pressure gas to act on the second control port of the main directional valve 3, causing the main directional valve 3 to switch to the open position. The main directional valve 3 can also be other types of directional valves with the same function, such as a solenoid valve or a hydraulically controlled directional valve.

[0079] Combination Figure 2The first suspension valve group 11 has ports A2 and A3 connected to the rodless chamber and rod chamber of the suspension cylinder 2, respectively, and port SP connected to the first accumulator 12. The first suspension valve group 11 includes a first directional valve 1101, a second directional valve 1103, and a third directional valve 1106. The first end of the first directional valve 1101 is connected to port A3, and the second end is connected in parallel to port A2 and the first end of the third directional valve 1106. The first directional valve 1101 is used to control the on / off state of the rodless chamber and rod chamber of the suspension cylinder 2. When the first directional valve 1101 is in the through position, the rodless chamber and rod chamber of the suspension cylinder 2 are connected, thereby realizing the differential function of the suspension cylinder 2, which can increase the effective stroke of the suspension cylinder 2 to improve the ground contact performance of the suspension. The first end of the second directional valve 1103 is connected to port A1, and the second end is connected in parallel to port SP and the second end of the third directional valve 1106. The second directional valve 1103, the main directional valve 3, and the third directional valve 1106 can work together to control the on / off state of the first accumulator 12 and the rodless chamber of the suspension cylinder 2 through the parallel first and second oil circuits, thereby achieving adaptive adjustment of suspension stiffness under different axle load driving conditions. Specifically, when both the main directional valve 3 and the second directional valve 1103 are in the through position, the rodless chamber of the suspension cylinder 2 is connected to the first accumulator 12 through the main directional valve 3, port A1 of the first suspension valve group 11, the second directional valve 1103, and port SP of the first suspension valve group 11 in sequence. Specifically, regarding the second oil circuit, when the third directional valve 1106 is in the through position, the rodless chamber of the suspension cylinder 2 connects to the first accumulator 12 via the A2 port of the first suspension valve group 11, the third directional valve 1106, and the SP port of the first suspension valve group 11 in sequence. The first directional valve 1101, the second directional valve 1103, and the third directional valve 1106 are all two-position, two-way solenoid directional valves (or two-position, two-way pneumatic directional valves), and their normally closed position functions as a bidirectional shut-off state.

[0080] In addition, the first suspension valve assembly 11 also includes a first damping orifice 1102, a second damping orifice 1105, and a first check valve 1104; the first damping orifice 1102 is located between the A1 port of the first suspension valve assembly 11 and the first end of the second reversing valve 1103; when the second reversing valve 1103 is in the through position, the first accumulator 12 is connected to the second accumulator 4 through the SP port of the first suspension valve assembly 11, the second reversing valve 1103, the A1 port of the first suspension valve assembly 11, and the A1 port and SP port of the second suspension valve assembly 11. At this time, the first damping orifice 1102 located between the A1 port of the first suspension valve assembly 11 and the second reversing valve 1103 can make the pressure of the second accumulator 4 and the first accumulator 12 gradually tend to be balanced, preventing pressure shock and improving vehicle handling stability.

[0081] The first end of the second damping orifice 1105 is connected in parallel to the second end of the second directional valve 1103 and the second end of the third directional valve 1106. The second end is connected to the SP port of the first suspension valve group 11. The first check valve 1104 is connected in parallel to both ends of the second damping orifice 1105. The oil inlet of the first check valve 1104 is connected to the first end of the second damping orifice 1105, and the oil outlet is connected to the second end of the second damping orifice 1105. The first one-way valve 1104 and the second damping orifice 1105 can form a one-way throttling assembly. When the vehicle encounters a raised obstacle during driving, the suspension cylinder 2 is compressed, and the oil in the rodless chamber of the suspension cylinder 2 can quickly enter the first accumulator 12 through the A2 port of the first suspension valve group 11, the third reversing valve 1106 and the first one-way valve 1104, which plays a role in buffering and damping and stabilizing the vehicle posture. When the vehicle encounters a pothole during driving, the suspension cylinder 2 is stretched, and the oil in the first accumulator 12 can replenish the rodless chamber of the suspension cylinder 2 through the second damping orifice 1105, the third reversing valve 1106 and the A2 port of the first suspension valve group 11. The second damping orifice 1105 can control the replenishment flow to limit the cylinder extension speed and further stabilize the vehicle posture.

[0082] Combination Figure 3 and Figure 4The second suspension valve group 1 has its P port connected to the hydraulic oil pump 5, and its T1 and T2 ports connected to the hydraulic oil tank 6. The outlet of the hydraulic oil pump 5 is connected to the inlet of the first relief valve 7, and the outlet of the first relief valve 7 is connected to the hydraulic oil tank 6. When the outlet pressure of the hydraulic oil pump 5 is higher than the relief pressure of the first relief valve 7, the first relief valve 7 automatically opens to avoid overpressure damage. The A1 and B1 ports of the second suspension valve group 1 are connected to the rodless chamber and the rod chamber of the suspension cylinder 2, respectively. The A2 port is connected to the second end of the main directional valve 3 and is connected in parallel with the A1 port of the first suspension valve group 11. The B2 port is connected to the rod chamber of the suspension cylinder 2. The SP port is connected to the A2 port and to the second accumulator 4. A sixth directional valve 103 is provided between the B2 and T2 ports of the second suspension valve group 1. The sixth directional valve 103 is a two-position, two-way solenoid directional valve (or a two-position, two-way pneumatic directional valve), and its normally closed position function is a bidirectional shut-off state. The second suspension valve group 1 also has three pressure measuring ports: M1, M2, and M3. Port M1 of the second suspension valve group 1 is connected to port A1, which is connected to the rodless chamber of the suspension cylinder 2, serving as the pressure measuring port for the working pressure of the rodless chamber of the suspension cylinder 2. Port M2 is connected to port B1, which is connected to the rod chamber of the suspension cylinder 2, serving as the pressure measuring port for the working pressure of the rod chamber of the suspension cylinder 2. Port M3 is connected to port A2 and port SP, which is connected to the second accumulator 4, serving as the pressure measuring port for the working pressure of the second accumulator 4. The second suspension valve assembly 1 also includes a second relief valve 104 and a third relief valve 105. The inlet of the second relief valve 104 is connected to the B2 port of the second suspension valve assembly 1 and is located downstream of the sixth directional valve 103. The outlet of the second relief valve 104 is connected to the T2 port of the second suspension valve assembly 1. The second relief valve 104 is used to protect the rod chamber of the suspension cylinder 2, the sixth directional valve 103 and the pipelines and joints connected to it in the oil circuit to prevent overpressure damage. The inlet of the third relief valve 105 is connected in parallel to the A2 port and the SP port of the second suspension valve assembly 1 through the third damping orifice 106. The outlet of the third relief valve 105 is connected to the T2 port of the second suspension valve assembly 1. The third relief valve 105 is used to protect the rodless chamber of the suspension cylinder 2, the second accumulator 4, the main directional valve 3 and the pipelines and joints connected to it in the oil circuit to prevent overpressure damage. The third damping orifice 106 can alleviate the pressure shock caused by pressure fluctuations to the third relief valve 105.

[0083] The hydropneumatic suspension system in this embodiment is applied to engineering vehicles, such as... Figure 4 The diagram shows a chassis suspension system for a five-axle crane. The aforementioned hydropneumatic suspension system is installed at the front left, rear left, front right, and rear right positions of the vehicle. The outlet of the hydraulic pump 5 is connected in parallel to the P port of the second suspension valve group 1 of each hydropneumatic suspension system. The hydropneumatic suspension system of this embodiment has the function of adaptively adjusting the suspension stiffness and damping under different axle load driving conditions.

[0084] To address the issue of excessive suspension damping, under the condition of constant vehicle load, the hydropneumatic suspension system of this embodiment can depressurize the rod-side chamber of suspension cylinder 2. This allows for a smaller cylinder diameter in suspension cylinder 2, reducing the interaction flow with the accumulator and achieving damping reduction. Combined with... Figure 1 and Figure 3 The principle of the hydropneumatic suspension system in this embodiment for depressurizing the rod chamber of the suspension cylinder 2 includes: putting the sixth directional valve 103 of the second suspension valve group 1 in the through position, and connecting the rod chamber of the suspension cylinder 2 back to the hydraulic oil tank 6 through the B2 port of the second suspension valve group 1, the sixth directional valve 103 and the T2 port of the second suspension valve group 1.

[0085] Furthermore, for hydropneumatic suspension systems with long connecting pipes for flow exchange between the existing accumulator and suspension cylinder 2, the length of the connecting pipes can be reduced by adding an accumulator near suspension cylinder 2, thereby reducing damping. Figure 4 Taking the chassis suspension system of a five-bridge crane as an example, in this embodiment, a third accumulator 14 is additionally provided for both the left rear and right rear positions of the hydropneumatic suspension system. The third accumulator 14 is connected to the rodless chamber of the suspension cylinder 2 in the corresponding position of the hydropneumatic suspension system through the twelfth directional valve 15. The valve position of the twelfth directional valve 15 is controlled by the fourth directional valve 10; the air inlet of the fourth directional valve 10 is connected to a third air source, and the first and second air outlets are respectively connected to the first and second control ports of the twelfth directional valve 15; when the left solenoid valve of the fourth directional valve 10 is energized, the fourth directional valve 10 is in the left position, the air inlet and the first air outlet are connected, and the third air source can output high-pressure gas through the fourth directional valve 10 to act on the first control port of the twelfth directional valve 15, the twelfth directional valve 15 switches to the through position, and the third accumulator 14... 4. The fourth directional valve 10 is connected to the rodless chamber of the suspension cylinder 2 via the twelfth directional valve 15. When the right solenoid valve of the fourth directional valve 10 is energized, the fourth directional valve 10 is in the right position, the air inlet and the second air outlet are connected, and the third air source can output high-pressure gas through the fourth directional valve 10 to act on the second control port of the twelfth directional valve 15. The twelfth directional valve 15 switches to the cut-off position, and the third accumulator 14 is disconnected from the rodless chamber of the suspension cylinder 2. When neither the left nor the right solenoid valve of the fourth directional valve 10 is energized, the fourth directional valve 10 is in the middle position, and the air inlet is cut off.

[0086] The control method for vehicles equipped with hydropneumatic suspension systems in the front left, rear left, front right, and rear right positions is explained. When the vehicle is moving and not steering or braking, the following applies to the hydropneumatic suspension systems in each position:

[0087] The A1 and B1 ports of the second suspension valve group 1 are kept closed. The working pressure of the rodless chamber of the suspension cylinder 2 is detected by the pressure sensor 13. The actual axle load can be calculated by multiplying the piston area of ​​the rodless chamber of the suspension cylinder 2 by the working pressure. In this embodiment, the suspension stiffness and damping can be adaptively adjusted in three axle load ranges. The three axle load ranges are: actual axle load ≤ first axle load G1, first axle load G1 < actual axle load ≤ second axle load G2, and actual axle load > second axle load G2. The first axle load G1 and the second axle load G2 are both preset axle loads.

[0088] When the actual axle load is less than or equal to the first axle load G1, combined with Figure 1 , Figure 2 , Figure 3 and Figure 4 This system ensures that the main directional valve 3 and the first directional valve 1101 of the first suspension valve group 11 are in the through position, while the second directional valve 1103 and the third directional valve 1106 of the first suspension valve group 11, as well as the sixth directional valve 103 of the second suspension valve group 1, are in the off position. The specific control method for this state includes: the sixth directional valve 103 of the second suspension valve group 1 is de-energized and is in the off position; the second electro-pneumatic directional valve 9 is energized, and the second air source drives the main directional valve 3 to the through position via the second electro-pneumatic directional valve 9; the first directional valve 1101 is energized and energized to the through position; both the second directional valve 1103 and the third directional valve 1106 are de-energized and are in the off position. In this state, the rodless chamber of suspension cylinder 2 is connected to the second accumulator 4 via the main directional valve 3 and the A2 and SP ports of the second suspension valve group 1. Under light axle load conditions (actual axle load less than or equal to the first axle load G1), the working pressure of the suspension system is effectively increased. The oil volume of the second accumulator 4 is sufficient to replenish the oil required by the rodless chamber when the suspension cylinder 2 extends during vehicle operation, increasing the stroke of the suspension cylinder 2 and improving the suspension contact performance. At the same time, when the suspension cylinder 2 is compressed during vehicle operation, the rodless chamber and the rod chamber of suspension cylinder 2 are connected through the A3 port of the first suspension valve group 11, the first directional valve 1101, and the A2 port of the first suspension valve group 11 to form a differential cylinder. This reduces the hydraulic oil exchange flow between the suspension cylinder 2 and the second accumulator 4, thereby reducing suspension damping and improving vehicle ride comfort.

[0089] When the actual axle load is greater than the first axle load G1 and less than or equal to the second axle load G2, combined with Figure 1 , Figure 2 , Figure 3 and Figure 4This causes the main directional valve 3 and the sixth directional valve 103 of the second suspension valve group 1 to be in the through position, and the first directional valve 1101, the second directional valve 1103, and the third directional valve 1106 of the first suspension valve group 11 to be in the cut-off position. The specific control method for this state includes: the sixth directional valve 103 is energized and reversed to the through position; the second electro-pneumatic directional valve 9 is energized, and the second air source drives the main directional valve 3 to reverse to the through position through the second electro-pneumatic directional valve 9; the first directional valve 1101, the second directional valve 1103, and the third directional valve 1106 are all de-energized, and their working positions are all in the cut-off position. In this state, the rod chamber of suspension cylinder 2 is connected to the hydraulic oil tank 6 through port B2 of the second suspension valve group 1, the sixth directional valve 103 of the second suspension valve group 1, and port T2 of the second suspension valve group 1. The rodless chamber of suspension cylinder 2 is connected to the second accumulator 4 through the main directional valve 3, port A2 and port SP of the second suspension valve group 1. In this state, the sprung weight of the suspension only establishes pressure in the rodless chamber of suspension cylinder 2. Compared with the prior art where the sprung weight of the suspension establishes pressure in both the rodless and rod chambers of suspension cylinder 2, this state can effectively reduce the cylinder diameter, rod diameter, weight and related technical parameters of suspension cylinder 2 while maintaining the consistent working pressure of the suspension system. It further reduces the hydraulic oil interaction flow between the rodless chamber of suspension cylinder 2 and the second accumulator 4, thereby reducing suspension damping and improving vehicle ride comfort.

[0090] When the actual axle load is greater than the second axle load G2, combined with Figure 1 , Figure 2 , Figure 3 and Figure 4This system ensures that the main directional valve 3, the second directional valve 1103 and the third directional valve 1106 of the first suspension valve group 11, and the sixth directional valve 103 of the second suspension valve group 1 are in the through position, while the first directional valve 1101 of the first suspension valve group 11 is in the cut-off position. The specific control method for this state includes: the sixth directional valve 103 is energized and switched to the through position; the second electro-pneumatic directional valve 9 is energized, and the second air source drives the main directional valve 3 to switch to the through position through the second electro-pneumatic directional valve 9; the first directional valve 1101 is de-energized, and its working position is the cut-off position; the second directional valve 1103 and the third directional valve 1106 are energized and switched to the through position. In this state, the rod-side chamber of the suspension cylinder 2 is connected to the hydraulic oil tank 6 through the B2 port of the second suspension valve group 1, the sixth directional valve 103, and the T2 port of the second suspension valve group 1. The rodless chamber of the suspension cylinder 2 is connected to the second accumulator 4 through the main directional valve 3, the A2 port and the SP port of the second suspension valve group 1. The rodless chamber of the suspension cylinder 2 is also connected to the first accumulator 12 through the parallel first oil circuit and the second oil circuit. The first oil circuit is connected to the first accumulator 12 through the main directional valve 3, the A1 port of the first suspension valve group 11, the second directional valve 1103 and the SP port of the first suspension valve group 11 in sequence. The second oil circuit is connected to the first accumulator 12 through the A2 port of the first suspension valve group 11, the third directional valve 1106 and the SP port of the first suspension valve group 11 in sequence. In this state, the weight on the suspension springs also only builds pressure in the rodless chamber of the suspension cylinder 2, and the rodless chamber of the suspension cylinder 2 is simultaneously connected to the first accumulator 12 and the second accumulator 4. This state reduces the stiffness of the suspension system by increasing the effective volume of the accumulator, thereby improving the ride comfort of the vehicle.

[0091] When the vehicle is moving and braking, if the actual axle load of the left front and right front hydraulic suspension systems exceeds the second axle load, the hydraulic suspension system with the actual axle load exceeding the second axle load is identified as the target braking suspension system; for the target braking suspension system, combined with... Figure 1 , Figure 2 , Figure 3 and Figure 4When the vehicle brakes, the second directional valve 1103 and the third directional valve 1106 of the first suspension valve assembly 11 are switched from the open position to the closed position. When the brake is released, the second directional valve 1103 is first switched from the closed position to the open position, and after a preset delay, the third directional valve 1106 is switched from the closed position to the open position. The specific control method during vehicle braking includes: switching the second directional valve 1103 and the third directional valve 1106 in the target suspension system from the energized state to the de-energized state, and switching the second directional valve 1103 and the third directional valve 1106 from the open position to the closed position. In this state, the rod chamber of the suspension cylinder 2 in the braking target suspension system is still connected to the hydraulic oil tank 6 through the B2 port of the second suspension valve group 1, the sixth directional valve 103, and the T2 port of the second suspension valve group 1. After the second directional valve 1103 and the third directional valve 1106 are switched to the cut-off position, the first oil circuit and the second oil circuit between the rodless chamber of the suspension cylinder 2 and the first accumulator 12 are both disconnected. The rodless chamber of the suspension cylinder 2 is switched from being connected to both the second accumulator 4 and the first accumulator 12 at the same time to being connected only to the second accumulator 4. The effective volume of the accumulator in the braking target suspension system is reduced, the stiffness of the suspension system is increased, the vehicle pitch angle is effectively reduced, and the vehicle handling stability is improved. The specific control method for releasing the vehicle's brakes includes: first energizing the second directional valve 1103 of the first suspension valve group 11 in the braking target suspension system, and then energizing the third directional valve 1106 after a preset time delay. The first accumulator 12 is first connected to the second accumulator 4 through the second damping orifice 1105, the second directional valve 1103, the first damping orifice 1102, the A1 port of the first suspension valve group 11, the A2 port of the second suspension valve group 1, and the SP port of the second suspension valve group 1. After the first accumulator 12 and the second accumulator 4 gradually achieve pressure balance, they are then connected to the rodless chamber of the suspension cylinder 2 through the third directional valve 1106 and the A2 port of the first suspension valve group 11. This can effectively reduce pressure shock, prevent the vehicle from nose-diving aggravated, and improve vehicle driving safety.

[0092] When a vehicle is moving and turning, if the hydraulic suspension system located on the opposite side of the turning direction (for example, if the vehicle is turning left, the opposite side corresponds to the hydraulic suspension systems in the right front and right rear positions, and the same applies to turning right) has an actual axle load greater than the second axle load, then the hydraulic suspension system with the actual axle load greater than the second axle load is identified as the target steering suspension system; for the target steering suspension system, combined with... Figure 1 , Figure 2 , Figure 3 and Figure 4When the vehicle is turning, the second directional valve 1103 and the third directional valve 1106 of the first suspension valve group 11 in the target suspension system are switched from the open position to the closed position. After the turn is completed, the second directional valve 1103 is first switched from the closed position to the open position, and after a preset delay, the third directional valve 1106 is switched from the closed position to the open position. The specific control method when the vehicle is driving and turning includes: switching the second directional valve 1103 and the third directional valve 1106 of the first suspension valve group 11 of the target suspension system from the energized state to the de-energized state, and switching the working position of the second directional valve 1103 and the third directional valve 1106 from the open position to the closed position. In this state, the rod-side chamber of the suspension cylinder 2 in the steering target suspension system is still connected to the hydraulic oil tank 6 through port B2 of the second suspension valve group 1, the sixth directional valve 103, and port T2 of the second suspension valve group 1. After the second directional valve 1103 and the third directional valve 1106 are switched to the cut-off position, the first and second oil circuits between the rodless chamber of the suspension cylinder 2 and the first accumulator 12 are both disconnected. The rodless chamber of the suspension cylinder 2 changes from being connected to both the second accumulator 4 and the first accumulator 12 simultaneously to being connected only to the second accumulator 4. The effective volume of the accumulator in the steering target suspension system is reduced, which increases the stiffness of the suspension system, effectively reduces the vehicle roll angle, and improves vehicle handling. Longitudinal stability; the specific control method at the end of vehicle steering includes: energizing the second directional valve 1103 of the first suspension valve group 11 in the steering target suspension system first, and energizing the third directional valve 1106 after a preset time delay; the first accumulator 12 is first connected to the second accumulator 4 through the second damping orifice 1105, the second directional valve 1103, the first damping orifice 1102, the A1 port of the first suspension valve group 11, the A2 port of the second suspension valve group 1, and the SP port of the second suspension valve group 1; the first accumulator 12 and the second accumulator 4 gradually achieve pressure balance before being connected to the rodless chamber of the suspension cylinder 2, which can effectively reduce pressure shock, prevent vehicle roll from aggravating, and improve vehicle driving safety.

[0093] Furthermore, the hydropneumatic suspension system in this embodiment can also achieve suspension lifting and lowering while the vehicle is stationary. Combined with... Figure 3The second suspension valve group 1 of the hydropneumatic suspension system also includes a fifth directional valve 101, a hydraulic two-way lock 102, and a second check valve 107. The inlet, outlet, first working port, and second working port of the fifth directional valve 101 are respectively connected to the P port, T1 port, A1 port, and B1 port of the second suspension valve group 1. The hydraulic two-way lock 102 is located between the fifth directional valve 101 and the A1 port and B1 port of the second suspension valve group 1. The hydraulic two-way lock 102 includes two hydraulic check valves, and the inlets of the two hydraulic check valves are respectively connected to the fifth directional valve. The first and second working oil ports of valve 101 are respectively connected to ports A1 and B1 of the second suspension valve assembly 1. When neither the first nor the second working oil port outputs hydraulic oil, the first working oil port of the second suspension valve assembly 1 and the second working oil port of the fifth directional valve 101 are unidirectionally cut off. When either the first or the second working oil port of the fifth directional valve 101 outputs hydraulic oil, the hydraulic two-way lock 102 is bidirectionally open. The hydraulic two-way lock 102 can effectively reduce the leakage of hydraulic oil from the suspension cylinder 2 back to the oil tank, and avoid abnormal vehicle posture caused by the retraction or extension of the suspension cylinder 2 due to hydraulic oil leakage after the vehicle has been driven or operated for a period of time. The second check valve 107 is located between the return port of the fifth directional valve 101 and the T1 port of the second suspension valve assembly 1. The second check valve 107 can prevent the hydraulic two-way lock 102 from being accidentally opened due to excessive back pressure of the return oil at the T1 port of the second suspension valve assembly 1.

[0094] The fifth directional valve 101 is connected to a first solenoid valve and a second solenoid valve. When the first solenoid valve is energized, the fifth directional valve 101 is in the left position. The oil inlet of the fifth directional valve 101 is connected to the first working oil port, and the second working oil port is connected to the return oil port. The hydraulic oil output from the first working oil port can supply oil to the rodless chamber of the suspension cylinder 2 through the A1 port of the second suspension valve group 1 to drive the suspension cylinder 2 to extend. When the second solenoid valve is energized, the fifth directional valve 101 is in the right position. The oil inlet of the fifth directional valve 101 is connected to the second working oil port, and the first working oil port is connected to the return oil port. The hydraulic oil output from the second working oil port can supply oil to the rod chamber of the suspension cylinder 2 through the B1 port of the second suspension valve group 1 to drive the suspension cylinder 2 to shorten. When neither the first nor the second solenoid valve is energized, the fifth directional valve 101 is in the neutral position. The inlet of the fifth directional valve 101 is closed, and both the first and second working ports are connected to the return port. At this time, neither the first nor the second working ports of the fifth directional valve 101 output hydraulic oil, and the hydraulic two-way lock 102 keeps the A1 and B1 ports of the second suspension valve group 1 closed. The fifth directional valve 101 needs to be kept in the neutral position when the vehicle is in motion. In one specific embodiment, the fifth directional valves 101 and the hydraulic two-way lock 102 of the various positions of the hydropneumatic suspension system can be connected in parallel within an integrated valve group.

[0095] The working principles of suspension lifting and lowering when the vehicle is stationary will be explained next.

[0096] Combination Figure 1 , Figure 2 and Figure 3When the suspension needs to be raised or lowered while the axle is carrying the vehicle, the main directional valve 3, the second directional valve 1103 and the third directional valve 1106 of the first suspension valve group 11 must all be kept in the off position. When suspension lifting is required, the hydraulic oil output by the hydraulic pump 5 flows into the P port of the second suspension valve group 1, the fifth directional valve 101 switches to the left position, the first directional valve 1101 of the first suspension valve group 11 needs to be kept in the cut-off position, the hydraulic oil flowing into the P port of the second suspension valve group 1 flows through the fifth directional valve 101 to the A1 port of the second suspension valve group 1, the B1 port of the second suspension valve group 1 is connected to T1, the rodless chamber of the suspension cylinder 2 enters the hydraulic oil, and the rod chamber returns oil through the B1 port and T1 port of the second suspension valve group 1 to the hydraulic oil tank 6. In this state, if the sixth directional valve 103 is in the open position, the rod chamber of the suspension cylinder 2 can also return oil through the sixth directional valve 103 and the T2 port of the second suspension valve group 1, and the suspension cylinder 2 extends to achieve suspension lifting. When suspension descent is required, the fifth directional valve 101 switches to the right position, and the sixth directional valve 103 of the second suspension valve group 1 needs to be kept in the off position. The hydraulic oil flowing into the P port of the second suspension valve group 1 flows through the fifth directional valve 101 to the B1 port of the second suspension valve group 1 to supply oil to the rod chamber of the suspension cylinder 2. The rodless chamber returns oil through the A1 port of the second suspension valve group 1, the fifth directional valve 101, and the T1 port of the second suspension valve group 1. At this time, if the first directional valve 1101 of the first suspension valve group 11 is in the open position, the hydraulic oil in the rodless chamber of the suspension cylinder 2 can also enter the rod chamber through the first directional valve 1101, and the suspension cylinder 2 shortens to achieve suspension descent.

[0097] When the axle is in a non-load-bearing vehicle state (outrigger support state), the tires are off the ground. Under the action of vehicle gravity, the suspension cylinder 2 tends to extend. At this time, the rod chamber and rodless chamber of the suspension cylinder 2 need to be disconnected. At the same time, the rod chamber of the suspension cylinder 2 cannot be depressurized. Therefore, when lifting and lowering the suspension axle in a non-load-bearing vehicle state, the main reversing valve 3, the sixth reversing valve 103 of the second suspension valve group 1, the first reversing valve 1101, the second reversing valve 1103 and the third reversing valve 1106 of the first suspension valve group 11 all need to be kept in the off position. Specifically, when the suspension needs to be lowered in a non-load-bearing vehicle state, the fifth directional valve 101 switches to the left position. The hydraulic oil output by the hydraulic pump 5 flows into the A1 port of the second suspension valve group 1 through the P port to supply oil to the rodless chamber of the suspension cylinder 2. The rod chamber of the suspension cylinder 2 is connected to the hydraulic oil tank 6 for return oil through the B1 port of the second suspension valve group 1, the fifth directional valve 101, and the T1 port of the second suspension valve group 1. The suspension cylinder 2 extends, realizing the suspension lowering. When the suspension lowers, the extension of the cylinder rod of the suspension cylinder 2 needs to overcome the friction of the suspension cylinder 2 itself, and usually there will be no stall. For suspension systems that may have a stall risk, damping can be set in the return oil line of the rod chamber of the suspension cylinder 2 to reduce the lowering speed by increasing the return oil back pressure and avoid the risk of stall.

[0098] When the suspension needs to be lifted in the non-load-bearing vehicle state, the fifth directional valve 101 of the second suspension valve group 1 is switched to the right position. The hydraulic oil output by the hydraulic oil pump 5 flows in through the P port of the second suspension valve group 1 and then supplies oil to the rod chamber of the suspension cylinder 2 through the fifth directional valve 101 and the B1 port of the second suspension valve group 1. The rodless chamber of the suspension cylinder 2 is connected to the hydraulic oil tank 6 for oil return through the B1 port of the second suspension valve group 1, the fifth directional valve 101 and the T1 port of the second suspension valve group 1. The suspension cylinder 2 is shortened, realizing the suspension lifting.

[0099] In another specific embodiment, if the engineering vehicle using the hydropneumatic suspension system is not equipped with outriggers capable of supporting the vehicle, then only suspension lifting and lowering under axle-borne vehicle conditions is required. Combined with... Figure 5The fifth directional valve 101 and the hydraulic two-way lock 102 in the second suspension valve group 1 are replaced by the seventh directional valve 109, the third check valve 1010, the eighth directional valve 1013, and the fourth check valve 1014. The oil inlet of the third check valve 1010 is connected to the P port of the second suspension valve group 1, and the oil outlet is connected to the oil inlet of the seventh directional valve 109. The oil outlet of the seventh directional valve 109 is connected to the A1 port of the second suspension valve group 1. The oil inlet of the eighth directional valve 1013 is connected to the B1 port of the second suspension valve group 1, and the oil outlet is connected to the oil inlet of the fourth check valve 1014. The oil outlet of the fourth check valve 1014 is connected to the T1 port of the second suspension valve group 1. The seventh directional valve 109 and the eighth directional valve 1013 are both solenoid directional valves, and both switch to the through position when energized. When suspension lifting is required, the seventh directional valve 109 and the eighth directional valve 1013 are both energized and switched to the through position. The first directional valve 1101, the second directional valve 1103, and the third directional valve 1106 of the first suspension valve group 11 are all switched to the cut-off position. The hydraulic oil output by the hydraulic pump 5 flows through the P port of the second suspension valve group 1 and the seventh directional valve 109 into the A1 port of the second suspension valve group 1 to supply oil to the rodless chamber of the suspension cylinder 2. The rod chamber of the suspension cylinder 2 returns to the oil tank through the B1 port of the second suspension valve group 1, the eighth directional valve 1013, and the T1 port of the second suspension valve group 1. If the sixth directional valve 103 is also in the through position, the rod chamber of the suspension cylinder 2 can also return oil through the sixth directional valve 103 and the T2 port of the second suspension valve group 1. The suspension cylinder 2 extends, realizing suspension lifting. When suspension descent is required, the first directional valve 1101 of the first suspension valve group 11 is switched to the through position, and the second directional valve 1103 and the third directional valve 1106 of the first suspension valve group 11, as well as the sixth directional valve 103, the seventh directional valve 109 and the eighth directional valve 1013 of the second suspension valve group 1, are all switched to the cut-off position. The rodless chamber and the rod chamber of the suspension cylinder 2 are connected through the first directional valve 1101. Under the action of vehicle gravity, the hydraulic oil in the rodless chamber of the suspension cylinder 2 can flow into the rod chamber through the first directional valve 1101 to realize suspension descent. When the suspension descends to the predetermined position, the first directional valve 1101 is switched to the cut-off position to stop the descent.

[0100] In another specific embodiment, combined with Figure 6If only suspension lifting is required under axle-loaded vehicle conditions, the fifth directional valve 101 and hydraulic two-way lock 102 in the second suspension valve group 1 are replaced with the ninth directional valve 1011 and the tenth directional valve 1012. The ninth directional valve 1011 is located between the P port and the A1 port of the second suspension valve group 1; the tenth directional valve 1012 is located between the B1 port and the T1 port of the second suspension valve group 1. Both the ninth directional valve 1011 and the tenth directional valve 1012 are electromagnetic directional valves. When the ninth directional valve 1011 is energized, it switches to the through position, and when the tenth directional valve 1012 is energized, it connects the B1 port and the T1 port of the second suspension valve group 1. When suspension lifting is required, both the ninth directional valve 1011 and the tenth directional valve 1012 are energized and switched to the open position. The first directional valve 1101, the second directional valve 1103, and the third directional valve 1106 of the first suspension valve group 11 remain in the closed position. The hydraulic oil output by the hydraulic pump 5 flows through the P port of the second suspension valve group 1, through the ninth directional valve 1011, into the A1 port of the second suspension valve group 1 to supply oil to the rodless chamber of the suspension cylinder 2. The rod chamber of the suspension cylinder 2 returns to the oil tank through the B1 port of the second suspension valve group 1, the tenth directional valve 1012, and the T1 port of the second suspension valve group 1. If the sixth directional valve 103 is also in the open position at this time, the rod chamber of the suspension cylinder 2 can also return to the oil tank through the sixth directional valve 103 and the T2 port of the second suspension valve group 1. When the oil returns, the suspension cylinder 2 extends, raising the suspension. When the suspension needs to be lowered, the first directional valve 1101 of the first suspension valve group 11 switches to the through position, and the second directional valve 1103 and the third directional valve 1106 of the first suspension valve group 11, as well as the sixth directional valve 103, the ninth directional valve 1011 and the tenth directional valve 1012 of the second suspension valve group 1, all switch to the cut-off position. The rodless chamber and the rod chamber of the suspension cylinder 2 are connected through the first directional valve 1101 of the first suspension valve group 11. Under the action of vehicle gravity, the hydraulic oil in the rodless chamber of the suspension cylinder 2 can flow into the rod chamber through the first directional valve 1101 to lower the suspension. When the suspension reaches the predetermined position, switching the first directional valve 1101 to the cut-off position stops the descent.

[0101] In another specific embodiment, considering factors such as internal leakage of the suspension cylinder 2, the axle may still drop under prolonged vehicle support conditions. Therefore, to delay axle drop, this embodiment ensures that the rod-side chamber of the suspension cylinder 2 is connected to the second accumulator 4 during vehicle support conditions. Figure 7In this embodiment, the second suspension valve group 1 also includes an eleventh directional valve 108. The first end of the eleventh directional valve 108 is connected in parallel to the B2 port of the second suspension valve group 1 and one end of the sixth directional valve 103 connected to the B2 port. The second end is connected in parallel to the SP port and A2 port of the second suspension valve group 1. Before the vehicle needs to be supported or the suspension axle needs to be lifted, the main directional valve 3 remains in the off position, the first directional valve 1101 of the first suspension valve group 11 also remains in the off position, and the eleventh directional valve 108 switches to the through position (in this embodiment, it is electrically controlled, and the eleventh directional valve 108 switches to the through position after power failure). The rod chamber of the suspension cylinder 2 is connected to the second accumulator 4 through the B2 port of the second suspension valve group 1, the eleventh directional valve 108, and the SP port of the second suspension valve group 1, so that the second accumulator 4 can maintain the pressure of the rod chamber of the suspension cylinder 2. When the vehicle is in motion, the eleventh directional valve 108 needs to be energized and in the cut-off position to prevent the oil in the rodless chamber of the second accumulator 4 and the suspension cylinder 2 from flowing to the rod chamber of the suspension cylinder 2 through the eleventh directional valve 108, or even to the hydraulic oil tank 6 through the sixth directional valve 103, when the main directional valve 3 is in the open position.

[0102] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hydropneumatic suspension system, characterized in that, include: Suspension cylinder (2) The main directional valve (3) is connected at its first end to the rodless chamber of the suspension cylinder (2); The first suspension valve group (11) has port A1 connected to the second end of the main directional valve (3), ports A2 and A3 connected to the rodless chamber and rod chamber of the suspension cylinder (2) respectively, and port SP connected to the first accumulator (12); the first suspension valve group (11) includes a first directional valve (1101), a second directional valve (1103) and a third directional valve (1106), the first end of the first directional valve (1101) is connected to port A3, and the second end is connected in parallel to port A2 and the first end of the third directional valve (1106); the first end of the second directional valve (1103) is connected to port A1, and the second end is connected in parallel to port SP and the second end of the third directional valve (1106); The second suspension valve group (1) has a P port connected to a hydraulic oil pump (5), T1 port and T2 port connected to a hydraulic oil tank (6), A1 port and B1 port connected to the rodless chamber and rod chamber of the suspension cylinder (2) respectively, A2 port connected to the second end of the main directional valve (3) and connected in parallel with the A1 port of the first suspension valve group (11), B2 port connected to the rod chamber of the suspension cylinder (2), SP port connected to A2 port and connected to a second accumulator (4), and a sixth directional valve (103) is provided between the B2 port and T2 port of the second suspension valve group (1). The main directional valve (3), the first directional valve (1101), the second directional valve (1103), the third directional valve (1106) and the sixth directional valve (103) all have a through position and a stop position; The first electro-pneumatic reversing valve (8) is located between the first gas source and the first control port of the main reversing valve (3). When the first electro-pneumatic reversing valve (8) is energized and connected, the first gas source can output high-pressure gas to act on the first control port of the main reversing valve (3) to switch the main reversing valve (3) to the cut-off position. The second electro-pneumatic reversing valve (9) is located between the second gas source and the second control port of the main reversing valve (3). When the second electro-pneumatic reversing valve (9) is energized and connected, the second gas source can output high-pressure gas to act on the second control port of the main reversing valve (3) to switch the main reversing valve (3) to the connected position. The first suspension valve assembly (11) also includes: The first damping orifice (1102) is located between the A1 port of the first suspension valve group (11) and the first end of the second reversing valve (1103); The second damping orifice (1105) has its first end connected in parallel to the second end of the second reversing valve (1103) and the second end of the third reversing valve (1106), and its second end is connected to the SP port of the first suspension valve group (11). The first check valve (1104) has an oil inlet connected to the first end of the second damping orifice (1105) and an oil outlet connected to the second end of the second damping orifice (1105).

2. The hydropneumatic suspension system according to claim 1, characterized in that, The second suspension valve assembly (1) also includes: The second relief valve (104) has its inlet connected to the B2 port of the second suspension valve group (1) and located downstream of the sixth directional valve (103), and its outlet connected to the T2 port of the second suspension valve group (1). The third relief valve (105) has its inlet port connected in parallel to the A2 port and SP port of the second suspension valve group (1) via the third damping hole (106), and its outlet port connected to the T2 port of the second suspension valve group (1).

3. The hydropneumatic suspension system according to claim 1, characterized in that, The first reversing valve (1101), the second reversing valve (1103), the third reversing valve (1106) of the first suspension valve group (11) and the sixth reversing valve (103) of the second suspension valve group (1) are all electromagnetic reversing valves, which switch from the cut-off position to the through position when energized.

4. The hydropneumatic suspension system according to claim 1, characterized in that, The second suspension valve assembly (1) also includes: The fifth directional valve (101) has an oil inlet, an oil return port, a first working oil port, and a second working oil port connected to the P port, T1 port, A1 port, and B1 port of the second suspension valve group (1), respectively. A hydraulic two-way lock (102) is located between port A1 and port B1 of the fifth directional valve (101) and the second suspension valve group (1); The second check valve (107) is located between the return port of the fifth directional valve (101) and the T1 port of the second suspension valve group (1); The fifth directional valve (101) is connected to a first solenoid valve and a second solenoid valve; When the first solenoid valve is energized, the fifth directional valve (101) is in the left position, and the oil inlet of the fifth directional valve (101) is connected to the first working oil port, and the second working oil port is connected to the return oil port. When the second solenoid valve is energized, the fifth directional valve (101) is in the right position, and the oil inlet and the second working oil port of the fifth directional valve (101) are connected, and the first working oil port and the return oil port are connected. When neither the first nor the second solenoid valve is energized, the fifth directional valve (101) is in the neutral position, the oil inlet of the fifth directional valve (101) is closed, and both the first and second working oil ports are connected to the return oil port.

5. The hydropneumatic suspension system according to claim 1, characterized in that, The second suspension valve assembly (1) further includes: The eleventh directional valve (108) has its first end connected in parallel to the B2 port of the second suspension valve group (1) and one end of the sixth directional valve (103) connected to the B2 port, and its second end connected in parallel to the SP port and A2 port of the second suspension valve group (1).

6. The hydropneumatic suspension system according to claim 1, characterized in that, Also includes: The first relief valve (7) has its inlet connected to the outlet of the hydraulic oil pump (5), and its outlet connected to the hydraulic oil tank (6).

7. The hydropneumatic suspension system according to claim 1, characterized in that, Also includes: The third accumulator (14) is connected to the rodless chamber of the suspension cylinder (2) via the twelfth directional valve (15); the twelfth directional valve (15) has a through position and a cut-off position; The valve positions of the fourth directional valve (10) and the twelfth directional valve (15) are controlled by the fourth directional valve (10); The inlet of the fourth reversing valve (10) is connected to the third air source, and the first outlet and the second outlet are respectively connected to the first control port and the second control port of the twelfth reversing valve (15). When the left solenoid valve of the fourth reversing valve (10) is energized, the fourth reversing valve (10) is in the left position, the air inlet and the first air outlet are connected, the third air source can output high pressure gas through the fourth reversing valve (10) to act on the first control port of the twelfth reversing valve (15), the twelfth reversing valve (15) switches to the through position, and the third accumulator (14) is connected to the rodless chamber of the suspension cylinder (2) through the twelfth reversing valve (15); When the right solenoid valve of the fourth reversing valve (10) is energized, the fourth reversing valve (10) is in the right position, the air inlet and the second air outlet are connected, and the third air source can output high pressure gas through the fourth reversing valve (10) to act on the second control port of the twelfth reversing valve (15). The twelfth reversing valve (15) switches to the cut-off position, and the third accumulator (14) is disconnected from the rodless chamber of the suspension cylinder (2). When neither the left nor the right solenoid valve of the fourth reversing valve (10) is energized, the fourth reversing valve (10) is in the neutral position and the air inlet is cut off.

8. The hydropneumatic suspension system according to claim 1, characterized in that, The second suspension valve assembly (1) also includes: The ninth directional valve (1011) is located between the P port and the A1 port of the second suspension valve group (1); The tenth directional valve (1012) is located between port B1 and port T1 of the second suspension valve group (1); The ninth directional valve (1011) and the tenth directional valve (1012) are both electromagnetic directional valves, which switch from the cut-off position to the through position when energized.

9. The hydropneumatic suspension system according to claim 1, characterized in that, The second suspension valve assembly (1) also includes: The third check valve (1010) and the seventh directional valve (109) are connected. The oil inlet of the third check valve (1010) is connected to the P port of the second suspension valve group (1), and the oil outlet is connected to the oil inlet of the seventh directional valve (109). The oil outlet of the seventh directional valve (109) is connected to the A1 port of the second suspension valve group (1). The fourth check valve (1014) and the eighth directional valve (1013) are provided. The oil inlet of the eighth directional valve (1013) is connected to the B1 port of the second suspension valve group (1), and the oil outlet is connected to the oil inlet of the fourth check valve (1014). The oil outlet of the fourth check valve (1014) is connected to the T1 port of the second suspension valve group (1). The seventh directional valve (109) and the eighth directional valve (1013) are both electromagnetic directional valves, which switch from the cut-off position to the through position when energized.

10. A vehicle, characterized in that, The vehicle is provided with an oil-air suspension system as described in any one of claims 1-9 at the front left, rear left, front right and rear right positions, and the oil outlet of the hydraulic oil pump (5) is connected in parallel with the P port of the second suspension valve group (1) of the oil-air suspension system at each position.

11. A method for controlling a vehicle, characterized in that, Based on the vehicle of claim 10, the control method includes: When the vehicle is moving and not steering or braking, for the hydropneumatic suspension system in each direction of the vehicle: Keep the A1 port and B1 port of the second suspension valve group (1) closed, use the pressure sensor (13) to obtain the working pressure of the rodless chamber of the suspension cylinder (2), and calculate the actual axle load based on the product of the working pressure of the rodless chamber of the suspension cylinder (2) and the piston area. When the actual axle load is less than or equal to the first axle load, the main reversing valve (3) and the first reversing valve (1101) of the first suspension valve group (11) are in the through position, and the second reversing valve (1103) of the first suspension valve group (11), the third reversing valve (1106) of the first suspension valve group (11) and the sixth reversing valve (103) of the second suspension valve group (1) are all in the shut-off position; When the actual axle load is greater than the first axle load and less than or equal to the second axle load, the main reversing valve (3) and the sixth reversing valve (103) of the second suspension valve group (1) are in the through position, and the first reversing valve (1101), the second reversing valve (1103) and the third reversing valve (1106) of the first suspension valve group (11) are all in the cut-off position. When the actual axle load is greater than the second axle load, the main reversing valve (3), the second reversing valve (1103) and the third reversing valve (1106) of the first suspension valve group (11) and the sixth reversing valve (103) of the second suspension valve group (1) are all in the through position, and the first reversing valve (1101) of the first suspension valve group (11) is in the cut-off position.

12. The vehicle control method according to claim 11, characterized in that, When the vehicle is moving and braking, if the actual axle load of the left front and right front hydraulic suspension systems is greater than the second axle load, the hydraulic suspension system with the actual axle load greater than the second axle load will be identified as the target braking suspension system. For the braking target suspension system, when the vehicle is braking, the second reversing valve (1103) and the third reversing valve (1106) of the first suspension valve group (11) are switched from the open position to the closed position. When the brake is released, the second reversing valve (1103) is switched from the closed position to the open position first, and after a preset time delay, the third reversing valve (1106) is switched from the closed position to the open position.

13. The vehicle control method according to claim 11, characterized in that, When the vehicle is moving and turning, if the actual axle load of the hydropneumatic suspension system located on the opposite side of the turning direction is greater than the second axle load, the hydropneumatic suspension system with the actual axle load greater than the second axle load is identified as the target steering suspension system. For the steering target suspension system, when the vehicle is turning, the second reversing valve (1103) and the third reversing valve (1106) of the first suspension valve group (11) are switched from the open position to the closed position. When the turning ends, the second reversing valve (1103) is switched from the closed position to the open position first, and after a preset time delay, the third reversing valve (1106) is switched from the closed position to the open position.

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