Hydraulic power system for driving a vehicle

Abstract

The present disclosure provides a hydraulic power system for driving a vehicle, which belongs to the field of hydraulic control. The hydraulic power system includes a power output unit, a wheel control unit and an execution unit, wherein the execution unit includes a first motor and a second motor; the wheel control unit includes a proportional reversing valve, a first hydraulically controlled reversing valve, a second hydraulically controlled reversing valve and a third hydraulically controlled reversing valve; the oil inlet of the proportional reversing valve is connected to the oil outlet of the power output unit, the oil outlet of the proportional reversing valve is connected to the oil inlet of the power output unit, the first working oil port of the proportional reversing valve is respectively connected to the first working oil port of the first hydraulically controlled reversing valve and the first working oil port of the first motor, and the second working oil port of the proportional reversing valve is connected to the second working oil port of the second motor; the present disclosure can flexibly drive the vehicle to move without affecting the volume of the vehicle through the hydraulic power system.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of hydraulic drive, and particularly relates to a hydraulic power system for driving a vehicle. Background Art

[0002] In the field of marine machinery, it is often necessary for a vehicle to carry some mechanical equipment.

[0003] In the related art, most vehicles use an engine to drive a gearbox, and the gearbox drives the wheels to make the vehicle move forward and backward.

[0004] However, when the load of the mechanical equipment to be carried is too large, the driving torque required by the wheels at this time becomes larger. If the traditional driving method is still used, it is necessary to increase the size of the engine and the gears of the gearbox, resulting in an increase in the volume of the vehicle, making it difficult for the vehicle to pass through a small space and unable to meet the transportation requirements. Summary of the Invention

[0005] The embodiments of the present disclosure provide a hydraulic power system for driving a vehicle, which can flexibly drive the vehicle to move without affecting the volume of the vehicle. The technical solution is as follows:

[0006] The embodiments of the present disclosure provide a hydraulic power system for driving a vehicle. The hydraulic power system includes a power output unit, a wheel control unit, and an execution unit. The execution unit includes a first motor and a second motor; the wheel control unit includes a proportional directional valve, a first pilot-operated directional valve, a second pilot-operated directional valve, and a third pilot-operated directional valve; the oil inlet of the proportional directional valve is communicated with the oil outlet of the power output unit, the oil outlet of the proportional directional valve is communicated with the oil inlet of the power output unit, the first working oil port of the proportional directional valve is respectively communicated with the first working oil port of the first pilot-operated directional valve, the first working oil port of the first motor, and the first working oil port of the third pilot-operated directional valve, and the second working oil port of the proportional directional valve is respectively communicated with the second working oil port of the second motor and the first working oil port of the second pilot-operated directional valve;

[0007] The second working oil port of the first pilot-operated directional valve is respectively communicated with the second working oil port of the first motor and the third working oil port of the second pilot-operated directional valve, and the third working oil port of the first pilot-operated directional valve is communicated with the first working oil port of the second motor; the second working oil port of the second pilot-operated directional valve is communicated with the first working oil port of the second motor; the second working oil port of the third pilot-operated directional valve is respectively communicated with the control oil port of the first pilot-operated directional valve and the control oil port of the second pilot-operated directional valve, and the control oil port of the third pilot-operated directional valve is communicated with the first working oil port of the third pilot-operated directional valve.

[0008] In yet another implementation manner of the present disclosure, the wheel control unit further includes a shuttle valve. A first working oil port of the shuttle valve is communicated with a first working oil port of the proportional directional valve. A second working oil port of the shuttle valve is communicated with a second working oil port of the proportional directional valve. A third working oil port of the shuttle valve is communicated with a first working oil port of the third hydraulic control directional valve.

[0009] In yet another implementation manner of the present disclosure, the wheel control unit further includes a flow regulating valve. An oil inlet of the flow regulating valve is communicated with a first working oil port of the proportional directional valve. An oil outlet of the flow regulating valve is communicated with a second working oil port of the proportional directional valve. A first working oil port of the flow regulating valve is communicated with a first working oil port of the second motor. A first control oil port of the flow regulating valve is communicated with its own oil inlet. A second control oil port of the flow regulating valve is communicated with its own first working oil port. A spool cross-sectional area of the first control oil port of the flow regulating valve is smaller than that of the second control oil port.

[0010] In yet another implementation manner of the present disclosure, the wheel control unit further includes a damping orifice. The damping orifice is located in a communication pipeline between the flow regulating valve and the second hydraulic control directional valve. The damping orifice is respectively communicated with a first working oil port of the flow regulating valve and a second working oil port of the second hydraulic control directional valve.

[0011] In yet another implementation manner of the present disclosure, the wheel control unit further includes a check valve group. The check valve group includes a first check valve, a second check valve, a third check valve, and a fourth check valve. An oil inlet of the first check valve is communicated with a first working oil port of the proportional directional valve. An oil outlet of the first check valve is communicated with an oil inlet of the flow regulating valve. An oil inlet of the second check valve is communicated with an oil outlet of the flow regulating valve. An oil outlet of the second check valve is communicated with a first working oil port of the proportional directional valve. An oil inlet of the third check valve is communicated with an oil outlet of the flow regulating valve. An oil outlet of the third check valve is communicated with a second working oil port of the proportional directional valve. An oil inlet of the fourth check valve is communicated with a second working oil port of the proportional directional valve. An oil outlet of the fourth check valve is communicated with an oil inlet of the flow regulating valve.

[0012] In yet another implementation manner of the present disclosure, the wheel control unit further includes a pressure detector. An oil inlet of the pressure detector is communicated with a third working oil port of the shuttle valve.

[0013] In yet another implementation manner of the present disclosure, the execution unit further includes a first brake cylinder and a second brake cylinder; the first brake cylinder is used to brake the first motor, and the second brake cylinder is used to brake the second motor; the rod chamber of the first brake cylinder is communicated with the third working oil port of the shuttle valve; the rod chamber of the second brake cylinder is communicated with the third working oil port of the shuttle valve.

[0014] In yet another implementation manner of the present disclosure, the power output unit includes a flow pump and a fuel tank; the oil outlet of the flow pump is communicated with the oil inlet of the proportional directional valve, and the oil inlet of the flow pump is communicated with the fuel tank.

[0015] In yet another implementation manner of the present disclosure, the power output unit further includes an oil cooler; the oil inlet of the oil cooler is communicated with the oil outlet of the proportional directional valve, and the oil outlet of the oil cooler is communicated with the fuel tank.

[0016] In yet another implementation manner of the present disclosure, the power output unit further includes a filter; the oil inlet of the filter is communicated with the oil outlet of the oil cooler, and the oil outlet of the filter is communicated with the fuel tank.

[0017] The beneficial effects brought by the technical solution provided by the embodiments of the present disclosure are as follows:

[0018] When using the hydraulic power system provided by the embodiments of the present disclosure to drive a vehicle, first, start the power output unit so that the hydraulic oil output by the power output unit enters the proportional directional valve.

[0019] When it is necessary to drive the vehicle forward through the hydraulic power system, it is necessary to drive the first motor and the second motor to rotate clockwise (forward rotation). At this time, the spool of the proportional directional valve moves to the left and is in the right position. The oil inlet in the proportional directional valve is communicated with the first working oil port, and the oil outlet in the proportional directional valve is communicated with the second working oil port. After the hydraulic oil output by the power output unit enters the proportional directional valve, the hydraulic oil enters the first working oil port of the first motor from the first working oil port of the proportional directional valve, driving the first motor to rotate forward, thereby driving the wheels on the corresponding side of the first motor to rotate forward to realize vehicle advancement.

[0020] Meanwhile, the hydraulic oil enters the third pilot-operated directional valve. The spool of the third pilot-operated directional valve is in the right position, and the first working oil port and the second working oil port of the third pilot-operated directional valve are not connected. The spools of the first pilot-operated directional valve and the second pilot-operated directional valve are in the left position. The spool of the first pilot-operated directional valve is in the left position, and the second working oil port and the third working oil port of the first pilot-operated directional valve are connected. The spool of the second pilot-operated directional valve is in the left position, and the second working oil port and the third working oil port of the second pilot-operated directional valve are connected. The hydraulic oil output from the second working oil port of the first motor enters the second working oil port of the first pilot-operated directional valve and enters the first working oil port of the second motor from the third working oil port of the first pilot-operated directional valve, driving the second motor to rotate forward, thereby driving the wheels on the other side to rotate forward to realize the vehicle's forward movement. At this time, the first motor and the second motor are in series. Since the flow rates of the first motor and the second motor are the same, their rotational speeds will remain the same.

[0021] When the wheels on one side of the vehicle are stuck and do not rotate, the pressure at the outlet of the proportional directional valve will rise. When the pressure rises until the spool of the third pilot-operated directional valve is pushed to the left position, the first working oil port and the second working oil port of the third pilot-operated directional valve are connected. At this time, the hydraulic oil enters the control oil port of the first pilot-operated directional valve and the control oil port of the second pilot-operated directional valve through the third pilot-operated directional valve respectively. The spools of the first pilot-operated directional valve and the second pilot-operated directional valve are pushed to the right position. At this time, the first working oil port of the first motor is connected to the first working oil port of the second motor through the first pilot-operated directional valve, and the second working oil port of the first motor is connected to the second working oil port of the second motor through the second pilot-operated directional valve. The first motor and the second motor are in parallel. The motor on the side that is not stuck will rotate, thereby driving the vehicle out of trouble.

[0022] When it is necessary to drive the vehicle backward through the hydraulic power system, it is necessary to drive the first motor and the second motor to rotate counterclockwise (reverse rotation). This process is similar to the above, only the spool of the proportional directional valve is shifted to the right and then in the left position.

[0023] When the spool of the proportional directional valve is in the middle position, the hydraulic oil output by the power output unit is blocked by the proportional directional valve. At this time, there is no hydraulic oil input to the first motor and the second motor, and the wheels do not rotate.

[0024] That is to say, the hydraulic power system provided by the embodiments of the present disclosure can be installed on the vehicle to be driven. Through this system, the first motor and the second motor can be driven, so that the first motor and the second motor provide a large output torque, and then drive the vehicle with a large load to move forward and backward. At the same time, the volume of the vehicle will not be increased, enabling the vehicle to move normally in a small space. Moreover, when the wheels on one side of the vehicle are stuck, it can also automatically get out of trouble, meeting the actual needs. Description of the Drawings

[0025] To more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0026] Figure 1 It is a schematic diagram of a hydraulic power system for driving a vehicle provided by an embodiment of the present disclosure.

[0027] The meanings of the symbols in the figure are as follows:

[0028] 1. Power output unit; 11. Flow pump; 13. Fuel tank; 14. Oil cooler; 16. Filter; 17. Motor;

[0029] 2. Wheel control unit; 21. Proportional direction valve; 22. First pilot-operated direction valve; 23. Second pilot-operated direction valve; 24. Third pilot-operated direction valve; 25. Shuttle valve; 26. Flow regulating valve; 27. Damping hole; 28. Check valve group; 281. First check valve; 282. Second check valve; 283. Third check valve; 284. Fourth check valve; 29. Pressure detector;

[0030] 3. Execution unit; 31. First motor; 32. Second motor; 33. First brake cylinder; 34. Second brake cylinder. Detailed implementation manners

[0031] To make the purpose, technical solutions and advantages of the present disclosure clearer, the following will further describe the embodiments of the present disclosure in detail with reference to the accompanying drawings.

[0032] The hydraulic power system for driving a vehicle provided by the embodiments of the present disclosure is used for hydraulically driving a vehicle, wherein the hydraulically driven vehicle includes a vehicle platform, a hydraulic oil source and wheels. The hydraulic oil source is connected to the vehicle platform, and the wheels are rotatably connected to the vehicle platform. Driven by the wheels, the vehicle platform moves. The vehicle platform is used to install large mechanical equipment, etc. The wheels on the same side correspond one-to-one to a motor (which will be described in detail below) in the hydraulic power system, and the wheels on the same side rotate under the drive of the corresponding motor. In this embodiment, the motors are the first motor and the second motor, and the wheels are on both sides. The wheels on the left side correspond to the first motor, and the wheels on the right side correspond to the second motor.

[0033] That is to say, the hydraulic power system for driving a vehicle provided by the embodiments of the present disclosure is used to drive the motors to rotate, thereby realizing the rotation of the wheels.

[0034] The embodiments of the present disclosure provide a hydraulic power system for driving a vehicle, as Figure 1As shown in the figure, the hydraulic power system includes a power output unit 1, a wheel control unit 2, and an execution unit 3. The execution unit 3 includes a first motor 31 and a second motor 32. The wheel control unit 2 includes a proportional directional valve 21, a first pilot-operated directional valve 22, a second pilot-operated directional valve 23, and a third pilot-operated directional valve 24.

[0035] The oil inlet of the proportional directional valve 21 is communicated with the oil outlet of the power output unit 1, and the oil outlet of the proportional directional valve 21 is communicated with the oil inlet of the power output unit 1. The first working oil port of the proportional directional valve 21 is respectively communicated with the first working oil port of the first pilot-operated directional valve 22, the first working oil port of the first motor 31, and the first working oil port of the third pilot-operated directional valve 24. The second working oil port of the proportional directional valve 21 is respectively communicated with the second working oil port of the second motor 32 and the first working oil port of the second pilot-operated directional valve 23.

[0036] The second working oil port of the first pilot-operated directional valve 22 is respectively communicated with the second working oil port of the first motor 31 and the third working oil port of the second pilot-operated directional valve 23. The third working oil port of the first pilot-operated directional valve 22 is communicated with the first working oil port of the second motor 32.

[0037] The second working oil port of the second pilot-operated directional valve 23 is communicated with the first working oil port of the second motor 32. The second working oil port of the third pilot-operated directional valve 24 is respectively communicated with the control oil port of the first pilot-operated directional valve 22 and the control oil port of the second pilot-operated directional valve 23. The control oil port of the third pilot-operated directional valve 24 is communicated with the first working oil port of the third pilot-operated directional valve 24.

[0038] When using the hydraulic power system provided by the embodiment of the present disclosure to drive a vehicle, first, start the power output unit 1 so that the hydraulic oil output by the power output unit 1 enters the proportional directional valve 21.

[0039] When it is necessary to drive the vehicle forward through the hydraulic power system, it is necessary to drive the first motor 31 and the second motor 32 to rotate clockwise in the forward direction.

[0040] For the proportional directional valve 21, after the spool of the proportional directional valve 21 moves to the left and is in the right position, the oil inlet P in the proportional directional valve 21 is communicated with the first working oil port a, and the oil outlet T in the proportional directional valve 21 is communicated with the second working oil port b. After the hydraulic oil output by the power output unit 1 enters the proportional directional valve 21, the hydraulic oil enters the first working oil port a of the first motor 31 from the first working oil port a of the proportional directional valve 21, driving the first motor 31 to rotate forward, thereby driving the wheels on one side to rotate forward to realize the vehicle's forward movement.

[0041] Meanwhile, the hydraulic oil enters the third hydraulic control directional valve 24. For the third hydraulic control directional valve 24, the spool of the third hydraulic control directional valve 24 is in the right position, and the first working oil port a and the second working oil port b of the third hydraulic control directional valve 24 are not connected. The spools of the first hydraulic control directional valve 22 and the second hydraulic control directional valve 23 are in the left position. The second working oil port b and the third working oil port c of the first hydraulic control directional valve 22 are connected. The spool of the second hydraulic control directional valve 23 is in the left position, and the second working oil port b and the third working oil port c of the second hydraulic control directional valve 23 are connected. The hydraulic oil output from the second working oil port b of the first motor 31 enters the second working oil port b of the first hydraulic control directional valve 22 and enters the first working oil port a of the second motor 32 from the third working oil port c of the first hydraulic control directional valve 22, driving the second motor 32 to rotate forward, thereby driving the wheels on one side to rotate forward to achieve vehicle forward movement. At this time, the first motor 31 and the second motor 32 are in series, and through the same flow rate of the first motor 31 and the second motor 32, their speeds will remain the same.

[0042] When the wheels on one side of the vehicle are stuck and do not rotate, the pressure at the oil outlet T of the proportional directional valve 21 will rise. When the pressure rises until the spool of the third hydraulic control directional valve 24 is pushed to the left position, the first working oil port a and the second working oil port b of the third hydraulic control directional valve 24 are connected. At this time, the hydraulic oil enters the control oil port d of the first hydraulic control directional valve 22 and the control oil port d of the second hydraulic control directional valve 23 through the third hydraulic control directional valve 24 respectively, and the spools of the first hydraulic control directional valve 22 and the second hydraulic control directional valve 23 are pushed to the right position. At this time, the first working oil port a of the first motor 31 is connected to the first working oil port a of the second motor 32 through the first hydraulic control directional valve 22, and the second working oil port b of the first motor 31 is connected to the second working oil port b of the second motor 32 through the second hydraulic control directional valve 23, and the first motor 31 and the second motor 32 are in parallel. The motor on the side that is not stuck will rotate, thereby driving the vehicle out of trouble.

[0043] When it is necessary to drive the vehicle to reverse through the hydraulic power system, it is necessary to drive the first motor 31 and the second motor 32 to rotate counterclockwise in the reverse direction. This process is similar to the above, only the spool of the proportional directional valve 21 is shifted to the right and then in the left position.

[0044] When the spool of the proportional directional valve 21 is in the middle position, the hydraulic oil output by the power output unit 1 is blocked by the proportional directional valve 21. At this time, there is no hydraulic oil input to the first motor 31 and the second motor 32, and the wheels do not rotate.

[0045] That is to say, the hydraulic power system provided by the embodiments of the present disclosure can be installed on a vehicle to be driven. By this system, the first motor 31 and the second motor 32 are driven, so that the first motor 31 and the second motor 32 provide a large output torque, and then drive a vehicle with a large load to move forward and backward. At the same time, the volume of the vehicle is not increased, so that the vehicle can move normally in a small space. Moreover, when one side of the wheels is stuck, it can also automatically get out of trouble to meet the actual needs.

[0046] Optionally, the power output unit 1 includes a flow pump 11 and a fuel tank 13. The oil outlet of the flow pump 11 is communicated with the oil inlet P of the proportional directional valve 21, and the oil inlet of the flow pump 11 is communicated with the fuel tank 13.

[0047] In the above implementation, the fuel tank 13 is used to provide power hydraulic oil for the entire hydraulic power system. The flow pump 11 is used to pump power hydraulic oil for the proportional directional valve 21 in the hydraulic power system, so as to drive the first motor 31 and the second motor 32 to rotate, and finally enable the vehicle to move.

[0048] In this embodiment, in order to detect whether the temperature of the hydraulic oil in the fuel tank 13 can meet the actual use requirements, a thermometer is usually arranged on the side wall of the fuel tank 13, so that the temperature in the fuel tank 13 can be observed in real time through the thermometer to determine whether it meets the actual requirements.

[0049] By the same token, in order to detect whether the oil volume in the fuel tank 13 meets the actual use requirements, a liquid level gauge is usually arranged on the side wall of the fuel tank 13, so that the depth of the hydraulic oil in the fuel tank 13 can be observed in real time through the liquid level gauge, and the volume of the hydraulic oil in the fuel tank 13 can be determined accordingly.

[0050] Optionally, the power output unit 1 further includes an electric motor 17, and the electric motor 17 is used to drive the flow pump 11.

[0051] The electric motor 17 is used to drive the flow pump 11 to rotate.

[0052] Exemplarily, the flow pump 11 is a fixed-displacement pump.

[0053] Setting the flow pump 11 as a fixed-displacement pump can make the flow pump 11 output a constant flow when the rotation speed is constant, that is, after the rotation speed of the first flow pump 11 is selected, the corresponding output flow does not change, so as to ensure the rotation stability of the first motor 31 and the second motor 32.

[0054] Optionally, the power output unit 1 further includes an oil cooler 14. The oil inlet a of the oil cooler 14 is communicated with the oil outlet b of the proportional directional valve 21, and the oil outlet b of the oil cooler 14 is communicated with the fuel tank 13.

[0055] In the above implementation, the oil cooler 14 is used to reduce the temperature of the hydraulic oil recycled into the fuel tank 13, so that the hydraulic oil flowing out of the rodless chamber in the actuator unit 3 can be quickly cooled, thereby improving the safety of the hydraulic power system.

[0056] Optionally, the power output unit 1 further includes a filter 16. The oil inlet of the filter 16 is communicated with the oil outlet of the oil cooler 14, and the oil outlet of the filter 16 is communicated with the fuel tank 13.

[0057] In the above implementation, the filter 16 can filter impurities in the hydraulic oil, prevent impurities from entering the fuel tank 13, and improve the use safety of the hydraulic power system. Driven by the flow pump 11, the filtered hydraulic oil re-enters the entire oil circuit without affecting the use of each valve component, and at the same time, it can also prevent the hydraulic oil containing impurities from affecting the normal use of the first motor 31 and the second motor 32.

[0058] Continue to refer to Figure 1 , optionally, the wheel control unit 2 further includes a shuttle valve 25. The first working oil port a of the shuttle valve 25 is communicated with the first working oil port a of the proportional directional valve 21, the second working oil port b of the shuttle valve 25 is communicated with the second working oil port b of the proportional directional valve 21, and the third working oil port c of the shuttle valve 25 is communicated with the first working oil port a of the third hydraulically controlled directional valve 24.

[0059] In the above implementation, the pressure at the third working oil port c of the shuttle valve 25 is equal to the greater of the pressures at the first working oil port a and the second working oil port b in the proportional directional valve 21. That is to say, if the pressure at the first working oil port a in the proportional directional valve 21 is greater than the pressure at the second working oil port b in the proportional directional valve 21, then the pressure at the third working oil port c of the shuttle valve 25 is equal to the pressure at the first working oil port a in the proportional directional valve 21, that is, the left side of the shuttle valve 25 is communicated ( Figure 1 the left side in ); if the pressure at the first working oil port a in the proportional directional valve 21 is less than the pressure at the second working oil port b in the proportional directional valve 21, then the pressure at the third working oil port c of the shuttle valve 25 is equal to the pressure at the second working oil port b in the proportional directional valve 21, that is, the right side of the shuttle valve 25 is communicated ( Figure 1 the right side in ). In this way, the shuttle valve 25 can automatically transmit the higher pressure to the third hydraulically controlled directional valve 24 according to the pressure change of the working oil ports of the proportional directional valve 21. When the pressure at the third working oil port of the shuttle valve 25 is greater than the spring pressure for moving the spool of the third hydraulically controlled directional valve 24, the third hydraulically controlled directional valve 24 can be automatically controlled to change direction.

[0060] Optionally, the wheel control unit 2 further includes a flow regulating valve 26. The oil inlet P of the flow regulating valve 26 is communicated with the first working oil port a of the proportional directional valve 21. The oil outlet T of the flow regulating valve 26 is communicated with the second working oil port b of the proportional directional valve 21. The first working oil port a of the flow regulating valve 26 is communicated with the first working oil port a of the second motor 32. The second working oil port b of the flow regulating valve 26 is not communicated with any valve components. The first control oil port d of the flow regulating valve 26 is communicated with its own oil inlet P. The second control oil port e of the flow regulating valve 26 is communicated with its own first working oil port a.

[0061] In this embodiment, the cross-sectional area ratio of the spool of the first control oil port d to the second control oil port e of the flow regulating valve 26 is 1:2.

[0062] Since the cross-sectional area ratio of the spool of the first control oil port d to the second control oil port e of the flow regulating valve 26 is 1:2, the pressure of the second control oil port e of the flow regulating valve 26 can be dynamically self-regulated, and the pressure of the second control oil port e of the flow regulating valve 26 is always maintained at half of the pressure of the first control oil port d of the flow regulating valve 26.

[0063] For example, when the pressure at the first working oil port a of the flow regulating valve 26 (equal to the pressure of the second working oil port b of the first motor 31 and the first working oil port a of the second motor 32) increases and is greater than the spring pressure at the second control oil port e, the spool can be pushed to the right position. In this way, the first working oil port a of the flow regulating valve 26 is communicated with the oil return port T, and the hydraulic oil is drained through the oil return port T of the flow regulating valve 26 until the first working oil port a of the flow regulating valve 26 is half of the pressure of the oil inlet P of the flow regulating valve 26. Similarly, when the pressure at the first working oil port a of the flow regulating valve 26 decreases and is less than the spring pressure at the first control oil port d, the spool can be pushed to the left position. In this way, the first working oil port a of the flow regulating valve 26 is communicated with the oil inlet P, and the first working oil port a of the flow regulating valve 26 can be refilled through the oil inlet P of the flow regulating valve 26 until the first working oil port a of the flow regulating valve 26 is half of the pressure of the oil inlet P of the flow regulating valve 26.

[0064] Through the above dynamic adjustment, the pressure of the first working oil port a of the second motor 32 and the second working oil port b of the first motor 31 can be maintained at half of the system pressure. In this way, the working pressure difference of the first motor 31 is half of the system pressure (the first oil port of the first motor 31 is equal to the system pressure), and the working pressure difference of the second motor 32 is also half of the system pressure (the second oil port of the second motor 32 is equal to 0). Therefore, the working pressure differences of the first motor 31 and the second motor 32 are the same, so the corresponding rotational speeds and torques will be the same. Therefore, when the vehicle is going straight, it will always maintain a straight line.

[0065] When the vehicle's steering wheel turns left, since the first motor 31 and the second motor 32 are in series (the so-called series means that the hydraulic oil flowing out of the first motor 31 can directly flow into the second motor 32 to drive the second motor 32 to rotate), the external force borne by the left wheel increases, corresponding to an increase in the working pressure difference of the first motor 31, exceeding half of the system pressure. At this time, the spool of the flow control valve 26 will move to the left position, and the high-pressure oil coming out of the proportional reversing valve 21 passes through the flow control valve 26 and is supplemented into the first working oil port a of the second motor 32. In this way, the hydraulic oil flow rate of the second motor 32 will be greater than the hydraulic oil flow rate passing through the first motor 31, and the rotational speed of the second motor 32 will be greater than the rotational speed of the first motor 31, that is, the rotational speed of the right wheel is greater than the rotational speed of the left wheel, so that the vehicle can turn left.

[0066] Similarly, when the vehicle's steering wheel turns right, since the first motor 31 and the second motor 32 are in series, the external force borne by the right wheel increases, corresponding to an increase in the working pressure difference of the second motor 32, exceeding half of the system pressure. At this time, the spool of the flow control valve 26 will move to the right position, and the high-pressure oil coming out of the second working oil port b of the first motor 31 passes through the flow control valve 26 and flows to the oil return port T of the proportional reversing valve 21. In this way, the hydraulic oil flow rate passing through the first motor 31 is greater than the hydraulic oil flow rate passing through the second motor 32, and the rotational speed of the first motor 31 is greater than the rotational speed of the second motor 32, that is, the rotational speed of the left wheel is greater than the rotational speed of the right wheel, so that the vehicle can turn right.

[0067] Optionally, the wheel control unit 2 further includes a damping orifice 27, and the damping orifice 27 is located in the communication pipeline between the flow control valve 26 and the second hydraulic control reversing valve 23. The damping orifice 27 is respectively communicated with the first working oil port a of the flow control valve 26 and the second working oil port b of the second hydraulic control reversing valve 23.

[0068] In the above embodiment, the damping orifice 27 plays a role in buffering pressure fluctuations.

[0069] By the same token, damping orifices are also provided between the first working oil port a of the flow control valve 26 and the second control oil port e, and between the oil inlet port P of the flow control valve 26 and the first control oil port d. In this way, through the arrangement of the damping orifices, the pressure on the control oil ports of the flow control valve 26 can be reduced, ensuring the pressure stability of the first control oil port d and the second control oil port e of the flow control valve 26 without fluctuations.

[0070] Optionally, the wheel control unit 2 further includes a one-way valve group 28, and the one-way valve group 28 includes a first one-way valve 281, a second one-way valve 282, a third one-way valve 283, and a fourth one-way valve 284; the oil inlet of the first one-way valve 281 is communicated with the first working oil port a of the proportional directional valve 21, and the oil outlet of the first one-way valve 281 is communicated with the oil inlet P of the flow regulating valve 26; the oil inlet of the second one-way valve 282 is communicated with the oil outlet T of the flow regulating valve 26, and the oil outlet of the second one-way valve 282 is communicated with the first working oil port a of the proportional directional valve 21; the oil inlet of the third one-way valve 283 is communicated with the oil outlet T of the flow regulating valve 26, and the oil outlet of the third one-way valve 283 is communicated with the second oil port b of the second motor 32; the oil inlet of the fourth one-way valve 284 is communicated with the second oil port b of the second motor 32, and the oil outlet of the fourth one-way valve 284 is communicated with the oil inlet P of the flow regulating valve 26.

[0071] In the above implementation, the one-way valve group 28 is used to restrict the flow direction of the hydraulic oil among the proportional directional valve 21, the flow regulating valve 26, and the second motor 32.

[0072] For example, the arrangement of the first one-way valve 281 enables the hydraulic oil to flow only from the first working oil port a of the proportional directional valve 21 to the oil inlet P of the flow regulating valve 26. The arrangement of the second one-way valve 282 enables the hydraulic oil to flow only from the oil outlet T of the flow regulating valve 26 to the first working oil port a of the proportional directional valve 21.

[0073] The arrangement of the third one-way valve 283 enables the hydraulic oil to flow only from the oil outlet T of the flow regulating valve 26 to the second oil port b of the second motor 32. The arrangement of the fourth one-way valve 284 enables the hydraulic oil to flow only from the second oil port b of the second motor 32 to the oil inlet P of the flow regulating valve 26.

[0074] Optionally, the wheel control unit 2 further includes a pressure detector 29, and the oil inlet of the pressure detector 29 is communicated with the third working oil port c of the shuttle valve 25.

[0075] In the above embodiment, since the pressure detector 29 is communicated with the third working oil port c of the shuttle valve 25, and the pressure of the third working oil port of the shuttle valve 25 is equal to the pressure of the higher oil port among the first working oil port a and the second working oil port b of the proportional directional valve 21, therefore, by being communicated with the third working oil port c of the shuttle valve 25, the pressure detector 29 can monitor and display the maximum pressure of the system in real time, so as to protect the system and prevent accidents caused by excessive pressure.

[0076] Exemplarily, the pressure detector 29 is a pressure sensor.

[0077] In this embodiment, the proportional directional valve 21 is a three-position four-way proportional directional valve. The first hydraulic control directional valve 22 and the second hydraulic control directional valve 23 are both hydraulic control two-position three-way directional valves. The third hydraulic control directional valve 24 is a hydraulic control two-position two-way directional valve. When the system pressure is lower than the spring setting value of the third hydraulic control directional valve 24, that is, when the first motor 31 and the second motor 32 are rotating normally, the spool of the third hydraulic control directional valve 24 is in the right position.

[0078] Optionally, the execution unit 3 further includes a first brake cylinder 33 and a second brake cylinder 34; the first brake cylinder 33 is used to brake the first motor 31, and the second brake cylinder 34 is used to brake the second motor 32.

[0079] The rodless cavity of the first brake cylinder 33 is communicated with the third working oil port c of the shuttle valve 25; the rodless cavity of the second brake cylinder 34 is communicated with the third working oil port c of the shuttle valve 25.

[0080] In the above implementation, the first brake cylinder 33 is used to brake the first motor 31, and the second brake cylinder 34 is used to brake the second motor 32.

[0081] When the spool of the proportional directional valve 21 is in the middle position, the hydraulic oil output by the flow pump 11 is blocked by the proportional directional valve 21. At the same time, the hydraulic oil in the rodless cavities of the first brake cylinder 33 and the second brake cylinder 34 enters the shuttle valve 25 through the third working oil port of the shuttle valve 25, and then enters the first working oil port a and the second working oil port b of the proportional directional valve 21, and flows back to the oil tank 13 through the oil return port T of the proportional directional valve 21. The piston of the first brake cylinder 33 extends under the action of its own spring to lock the first motor 31 to prevent it from rotating. Similarly, the piston rod of the second brake cylinder 34 extends under the action of its own spring to lock the second motor 32 to prevent it from rotating, thereby braking the wheels.

[0082] That is to say, by setting the first brake cylinder 33 and the second brake cylinder 34, the wheels of the vehicle can be locked to brake it.

[0083] Optionally, the hydraulic power system further includes a controller, and the controller is electrically connected to the proportional directional valve 21.

[0084] In the above implementation, the working states of the proportional directional valve 21 and the like can be automatically controlled by the controller, improving the working efficiency.

[0085] The following briefly introduces the working mode of the hydraulic power system provided by the embodiments of the present disclosure:

[0086] When using the hydraulic power system provided by the embodiments of the present disclosure to drive a vehicle, first, start the power output unit 1 so that the hydraulic oil output by the power output unit 1 enters the proportional directional valve 21.

[0087] When it is necessary to drive the vehicle forward (the first motor 31 and the second motor 32 rotate forward), the hydraulic oil output by the flow pump 11 enters the proportional directional valve 21. At this time, the spool of the proportional directional valve 21 is in the right position. The oil inlet P in the proportional directional valve 21 is communicated with the first working oil port a, and the oil outlet T in the proportional directional valve 21 is communicated with the second working oil port b. The hydraulic oil enters the first working oil port a of the first motor 31 from the first working oil port a of the proportional directional valve 21, driving the first motor 31 to rotate forward, thereby driving the wheels on one side to rotate forward to realize the vehicle's forward movement.

[0088] At the same time, the hydraulic oil enters the third pilot-operated directional valve 24. For the third pilot-operated directional valve 24, the spool of the third pilot-operated directional valve 24 is in the right position, and the first working oil port a and the second working oil port b of the third pilot-operated directional valve 24 are not communicated. The spools of the first pilot-operated directional valve 22 and the second pilot-operated directional valve 23 are in the left position.

[0089] The second working oil port b of the first pilot-operated directional valve 22 is communicated with the third working oil port c. The spool of the second pilot-operated directional valve 23 is in the left position, and the second working oil port b of the second pilot-operated directional valve 23 is communicated with the third working oil port c. The hydraulic oil output from the second working oil port b of the first motor 31 enters the second working oil port b of the first pilot-operated directional valve 22 and enters the first working oil port a of the second motor 32 from the third working oil port c of the first pilot-operated directional valve 22, driving the first motor 31 to rotate forward, thereby driving the wheels on one side to rotate forward to realize the vehicle's forward movement. At this time, the first motor 31 and the second motor 32 are in series, and the flow rates of the first motor 31 and the second motor 32 are the same, and their rotational speeds will remain the same.

[0090] When the wheels on one side of the vehicle are stuck and do not rotate, the pressure at the oil outlet T of the proportional directional valve 21 will rise. When the pressure rises until the spool of the third pilot-operated directional valve 24 is pushed to the left position, the first working oil port a and the second working oil port b of the third pilot-operated directional valve 24 are communicated. At this time, the hydraulic oil enters the control oil port d of the first pilot-operated directional valve 22 and the control oil port d of the second pilot-operated directional valve 23 through the third pilot-operated directional valve 24 respectively, and the spools of the first pilot-operated directional valve 22 and the second pilot-operated directional valve 23 are pushed to the right position. At this time, the first working oil port a of the first motor 31 is communicated with the first working oil port a of the second motor 32 through the first pilot-operated directional valve 22, and the second working oil port b of the first motor 31 is communicated with the second working oil port b of the second motor 32 through the second pilot-operated directional valve 23. The first motor 31 and the second motor 32 are in parallel. The motor on the side that is not stuck will rotate, thereby driving the vehicle out of trouble.

[0091] When it is necessary to drive the vehicle to reverse through the hydraulic power system, it is necessary to drive the first motor 31 and the second motor 32 to rotate counterclockwise (reverse rotation). This process is similar to the above, only the spool of the proportional reversing valve 21 is shifted to the right and then in the left position.

[0092] When the spool of the proportional reversing valve 21 is in the middle position, the hydraulic oil output by the power output unit 1 is blocked by the proportional reversing valve 21. At this time, no hydraulic oil is input to the first motor 31 and the second motor 32, and the wheels do not rotate. At the same time, the hydraulic oil in the rod chamber of the first brake cylinder 33 and the rod chamber of the second brake cylinder 34 enters the shuttle valve 25 through the third working oil port of the shuttle valve 25, then enters the first working oil port a and the second working oil port b of the proportional reversing valve 21, and flows back to the fuel tank 13 through the oil return port T of the proportional reversing valve 21. The piston of the first brake cylinder 33 extends under the action of its own spring to lock the first motor 31 to prevent it from rotating. Similarly, the piston rod of the second brake cylinder 34 extends under the action of its own spring to lock the second motor 32 to prevent it from rotating, thereby braking the wheels.

[0093] The above are only optional embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A hydraulic power system for driving a vehicle, characterized in that, the hydraulic power system includes a power output unit (1), a wheel control unit (2) and an execution unit (3), and the execution unit (3) includes a first motor (31) and a second motor (32); the wheel control unit (2) includes a proportional direction valve (21), a first hydraulic control direction valve (22), a second hydraulic control direction valve (23) and a third hydraulic control direction valve (24); the oil inlet of the proportional direction valve (21) is communicated with the oil outlet of the power output unit (1), the oil outlet of the proportional direction valve (21) is communicated with the oil inlet of the power output unit (1), the first working oil port of the proportional direction valve (21) is respectively communicated with the first working oil port of the first hydraulic control direction valve (22), the first working oil port of the first motor (31) and the first working oil port of the third hydraulic control direction valve (24), and the second working oil port of the proportional direction valve (21) is respectively communicated with the second working oil port of the second motor (32) and the first working oil port of the second hydraulic control direction valve (23); the second working oil port of the first hydraulic control direction valve (22) is respectively communicated with the second working oil port of the first motor (31) and the third working oil port of the second hydraulic control direction valve (23), and the third working oil port of the first hydraulic control direction valve (22) is communicated with the first working oil port of the second motor (32); the second working oil port of the second hydraulic control direction valve (23) is communicated with the first working oil port of the second motor (32); the second working oil port of the third hydraulic control direction valve (24) is respectively communicated with the control oil port of the first hydraulic control direction valve (22) and the control oil port of the second hydraulic control direction valve (23), and the control oil port of the third hydraulic control direction valve (24) is communicated with the first working oil port of the third hydraulic control direction valve (24).

2. The hydraulic power system according to claim 1, characterized in that, the wheel control unit (2) further includes a shuttle valve (25), the first working oil port of the shuttle valve (25) is communicated with the first working oil port of the proportional direction valve (21), the second working oil port of the shuttle valve (25) is communicated with the second working oil port of the proportional direction valve (21), and the third working oil port of the shuttle valve (25) is communicated with the first working oil port of the third hydraulic control direction valve (24).

3. The hydraulic power system according to claim 1, characterized in that, the wheel control unit (2) further includes a flow regulating valve (26); The oil inlet of the flow control valve (26) is communicated with the first working oil port of the proportional directional valve (21), the oil outlet of the flow control valve (26) is communicated with the second working oil port of the proportional directional valve (21), the first working oil port of the flow control valve (26) is communicated with the first working oil port of the second motor (32), the first control oil port of the flow control valve (26) is communicated with its own oil inlet, the second control oil port of the flow control valve (26) is communicated with its own first working oil port, and the valve core cross-sectional area of the first control oil port of the flow control valve (26) is smaller than that of the second control oil port.

4. The hydraulic power system according to claim 3, wherein, the wheel control unit (2) further includes a damping orifice (27), the damping orifice (27) is located in the connecting pipeline between the flow control valve (26) and the second hydraulic control directional valve (23), and the damping orifice (27) is respectively communicated with the first working oil port of the flow control valve (26) and the second working oil port of the second hydraulic control directional valve (23).

5. The hydraulic power system according to claim 3, wherein, the wheel control unit (2) further includes a check valve group (28), and the check valve group (28) includes a first check valve (281), a second check valve (282), a third check valve (283) and a fourth check valve (284); the oil inlet of the first check valve (281) is communicated with the first working oil port of the proportional directional valve (21), and the oil outlet of the first check valve (281) is communicated with the oil inlet of the flow control valve (26); the oil inlet of the second check valve (282) is communicated with the oil outlet of the flow control valve (26), and the oil outlet of the second check valve (282) is communicated with the first working oil port of the proportional directional valve (21); the oil inlet of the third check valve (283) is communicated with the oil outlet of the flow control valve (26), and the oil outlet of the third check valve (283) is communicated with the second working oil port of the proportional directional valve (21); the oil inlet of the fourth check valve (284) is communicated with the second working oil port of the proportional directional valve (21), and the oil outlet of the fourth check valve (284) is communicated with the oil inlet of the flow control valve (26).

6. The hydraulic power system according to claim 2, wherein, the wheel control unit (2) further includes a pressure detector (29), and the oil inlet of the pressure detector (29) is communicated with the third working oil port of the shuttle valve (25).

7. The hydraulic power system according to claim 2, wherein, the execution unit (3) further includes a first brake cylinder (33) and a second brake cylinder (34); the first brake cylinder (33) is used to brake the first motor (31), and the second brake cylinder (34) is used to brake the second motor (32); the rodless cavity of the first brake cylinder (33) is communicated with the third working oil port of the shuttle valve (25); The rod chamber of the second brake cylinder (34) is communicated with the third working oil port of the shuttle valve (25).

8. The hydraulic power system according to claim 1, characterized in that, the power output unit (1) includes a flow pump (11) and an oil tank (13); the oil outlet of the flow pump (11) is communicated with the oil inlet of the proportional directional valve (21), and the oil inlet of the flow pump (11) is communicated with the oil tank (13).

9. The hydraulic power system according to claim 8, characterized in that, the power output unit (1) further includes an oil cooler (14); the oil inlet of the oil cooler (14) is communicated with the oil outlet of the proportional directional valve (21), and the oil outlet of the oil cooler (14) is communicated with the oil tank (13).

10. The hydraulic power system according to claim 9, characterized in that, the power output unit (1) further includes a filter (16); the oil inlet of the filter (16) is communicated with the oil outlet of the oil cooler (14), and the oil outlet of the filter (16) is communicated with the oil tank (13).

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