A hydraulic system with electric control and steering wheel steering

Abstract

The application discloses a hydraulic system with electric control and steering wheel steering, comprising a priority valve, a steering valve, a steering gear, a reversing valve, a steering cylinder, an unloading valve, a pump and a hydraulic oil tank. The hydraulic system is simultaneously provided with steering wheel steering and electric control steering, and respective control advantages are exerted. Through internal control of the steering valve, only steering wheel steering control flow is output, that is, the steering wheel steering is prior, and steering control contradiction is avoided. When electric control steering fails, electric control steering output is cut off, at this time, the steering wheel steering is not affected, steering can be continuously controlled, and steering function safety is improved.

Description

Technical Field

[0001] This invention relates to a hydraulic system with electronic control and steering wheel, belonging to the field of hydraulic control technology for engineering machinery. Background Technology

[0002] Currently, most hydraulic steering systems used in loaders rely on steering wheel control. The steering gear outputs control signals to a priority valve, which in turn controls the directional valve to regulate the flow to the steering system. To improve the micro-control of the steering system at high speeds, loaders typically require several steering wheel turns for full steering. However, loaders, especially when operating in confined spaces, require frequent and rapid turns. Existing steering wheel systems are physically demanding, leading to driver fatigue. Newer electronic steering solutions offer easier operation, but their micro-control at high speeds is less precise, and the safety risks associated with electronic systems are higher than those with mechanical or hydraulic systems. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a hydraulic system with both electronic control and steering wheel steering, thereby resolving the problem of the coexistence of two steering operation methods in existing technologies and the safety risks associated with electronic steering systems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a hydraulic system with electronic control and steering wheel steering, including a priority valve, a steering gear, a directional valve, a steering cylinder, a pump, and a hydraulic oil tank. The pump inlet is connected to the hydraulic oil tank, and the outlet is connected to the priority valve inlet P1. The priority valve outlet CF is connected to the steering gear inlet P3 and the directional valve inlet P4. The directional valve ports A and B are respectively connected to the rod-side and rodless-side chambers of the steering cylinder. The priority valve outlet EF, the steering gear return port T3, and the directional valve return port T4 are all connected to the hydraulic oil tank. The system also includes a steering valve. The steering valve inlet P2 is connected to the priority valve outlet CF; the steering valve outlet CR is connected to the directional valve control port a; the steering valve outlet CL is connected to the directional valve control port b; the steering valve port LS is connected to the steering gear signal port LS3; the steering valve port LS2 is connected to the priority valve port LS1; the steering valve port R2 is connected to the steering gear outlet R3; the steering valve port L2 is connected to the steering gear outlet L3; and the steering valve return port T2 is connected to the hydraulic oil tank. When the directional valve is used for steering wheel turning and stopping steering, it controls the oil flowing through the directional valve to flow directly back to the hydraulic oil tank; and when used for electronic steering, it controls the oil output by the priority valve to flow out through the oil outlet of the steering valve, controls the directional valve connected thereto to switch direction, and causes the steering cylinder to move.

[0005] Furthermore, the steering valve includes a signal selection valve, a steering main valve, a shut-off valve, a left-turn solenoid valve, a right-turn solenoid valve, a pilot solenoid valve, a shut-off control valve, and a pressure reducing valve; The steering valve inlet P2 is simultaneously connected to the steering main valve inlet P0 and the pressure reducing valve inlet K0. The oil outlet A0 of the steering main valve is connected to the oil inlet A1 of the shut-off valve, and the oil outlet B0 of the steering main valve is connected to the oil inlet B1 of the shut-off valve. The return port T0 of the steering main valve is connected to the return port T2 of the steering valve. The steering main valve signal feedback port L0 is simultaneously connected to the spring chamber control port L2 of the signal selection valve and the oil inlet port L1 of the shut-off valve. The steering main valve control port a0 is simultaneously connected to the oil outlet port a1 of the right turn solenoid valve and the spring chamber control port a2 of the right turn solenoid valve. The steering main valve control port b0 is simultaneously connected to the oil outlet b1 of the left turn solenoid valve and the spring chamber control port b2 of the left turn solenoid valve. The shut-off valve outlet A2 is simultaneously connected to the steering valve outlet R2 and the steering valve outlet CR; The shut-off valve outlet B2 is simultaneously connected to the steering valve outlet L2 and the steering valve outlet CL; The oil outlet port O1 of the shut-off valve and the oil return port T7 of the shut-off valve spring cavity are simultaneously connected to the oil return port T2 of the steering valve. The shut-off valve control port K7 is simultaneously connected to the outlet port K6 of the pilot solenoid valve, the inlet port K8 of the left-turn solenoid valve, and the inlet port K9 of the right-turn solenoid valve. The oil outlet K1 of the pressure reducing valve is simultaneously connected to the control oil outlet K2 of the pressure reducing valve and the oil inlet K3 of the shut-off control valve. The oil outlet K4 of the cut-off control valve is connected to the oil inlet K5 of the pilot solenoid valve, and the control oil port L6 of the cut-off control valve is simultaneously connected to the oil outlet L4 of the signal selection valve and the oil port LS of the steering valve. The oil inlet L3 and the control oil inlet L5 of the signal selection valve are simultaneously connected to the oil inlet LS2 of the steering valve. The oil return port O2 of the left-turn solenoid valve, the oil return port O3 of the right-turn solenoid valve, the oil return port O7 of the spring chamber of the pressure reducing valve, the oil return port O5 and the oil return port O6 of the cut-off control valve, and the oil return port O3 and the oil return port O4 of the pilot solenoid valve are all connected to the oil return port T2 of the steering valve.

[0006] Furthermore, when there is no steering action, the steering gear signal port LS3 is connected to the return port T3, the left turn solenoid valve outlet port b1 and return port O2 are connected, and the right turn solenoid valve outlet port a1 and return port O3 are connected. When the reversing valve is in the neutral position, the reversing valve disconnects oil outlet A and oil outlet B, and the steering cylinder remains stationary.

[0007] Furthermore, when turning the steering wheel alone, the oil outlet b1 and oil return port O2 of the left-turn solenoid valve are connected, and the oil outlet a1 and oil return port O3 of the right-turn solenoid valve are connected. The steering gear is controlled to turn. The steering gear signal port LS3 is connected to the steering load. The pump output oil enters the steering gear inlet port P3 through the priority valve port CF. When turning left, the oil flows out from the steering gear outlet port L3, through the steering valve port L2 to port CL, and controls the reversing valve to switch direction through the reversing valve control port b. The oil at the priority valve port CF flows out from port A through the reversing valve port P4, causing the steering cylinder to retract and driving the vehicle to turn left. When turning right, the oil flows out from the steering gear outlet port R3, through the steering valve port R2 to port CR, and controls the reversing valve to switch direction through the reversing valve control port a. The oil at the priority valve port CF flows out from port B through the reversing valve port P4, causing the steering cylinder to extend and driving the vehicle to turn right.

[0008] Furthermore, during stand-alone electronic steering, the steering gear signal port LS3 is connected to the oil return port T3; When the electric left turn is activated, the pilot solenoid valve and the left turn solenoid valve are energized, connecting the inlet K5 and outlet K6 of the pilot solenoid valve, and connecting the inlet K8 of the left turn solenoid valve to the outlet b1 and control port b2. This causes the shut-off valve to switch to the left position under control pressure, connecting port A1 to port A2, port B1 to port B2, and port L1 to port O1. The pressure at the control port b2 of the left turn solenoid valve is adjusted to build pressure at the control port b0 of the steering main valve, pushing the steering main valve spool to the right position. The pump output oil enters the main directional valve inlet P0 through the priority valve port CF, flows out from the outlet B0, flows out through the shut-off valve port B2, connects to the steering valve port CL, and controls the directional valve to switch direction through the directional valve control port b. The oil in the priority valve port CF flows out from the directional valve port A through the directional valve port P4, causing the steering cylinder to retract and drive the vehicle to turn left. When the electric right turn is activated, the pilot solenoid valve and the right turn solenoid valve are energized, so that the oil inlet K5 and oil outlet K6 of the pilot solenoid valve are connected, and the oil inlet K9 of the right turn solenoid valve is connected to the oil outlet a1 and the control port b2. The pressure of the control port a2 of the right turn solenoid valve is adjusted, and the pressure is established at the control port a0 of the steering main valve, which pushes the steering main valve core to work in the left position. The pump output oil enters the inlet P0 of the main directional valve through the priority valve port CF, flows out from the outlet A0, flows out through the shut-off valve port A2, connects to the steering valve port CR, and controls the directional valve to switch direction through the directional valve control port a. The oil in the priority valve port CF flows out from the directional valve port B through the directional valve port P4, causing the steering cylinder to extend and drive the vehicle to turn right.

[0009] Furthermore, when the left-turn solenoid valve and the right-turn solenoid valve are energized, they control the steering gear to turn. The steering gear signal port LS3 is connected to the steering load, and the steering valve oil port LS also establishes the steering load. The steering valve oil port LS is simultaneously connected to the oil outlet L4 of the signal selection valve and the control oil port L6 of the cut-off control valve. Under the action of the control oil port, the cut-off control valve connects the oil port K4 to the return oil port O5, so that the cut-off valve, the left-turn solenoid valve and the right-turn solenoid valve cannot receive control oil and cannot realize electric steering.

[0010] Furthermore, when the electronic steering malfunctions, the power supply to the pilot solenoid valve is disconnected, connecting the oil outlet K6 of the pilot solenoid valve to the oil return port O3, preventing the shut-off valve, left-turn solenoid valve, and right-turn solenoid valve from receiving control oil and thus preventing electronic steering.

[0011] Furthermore, the hydraulic system also includes an unloading valve; The priority valve port LS1 is simultaneously connected to the steering valve port LS2 and the unloading valve control port LS6; The oil outlet CR of the steering valve is simultaneously connected to the control port a of the reversing valve and the oil port R6 of the unloading valve. The oil outlet CL of the steering valve is simultaneously connected to the control port b of the reversing valve and the oil port L6 of the unloading valve. The unloading valve return port T6 is connected to the hydraulic oil tank; The unloading valve is used to switch to the left position after sensing the pressure transmitted by the priority valve, and the unloading valve oil port L6 and unloading valve oil port R6 are blocked so that the oil cannot flow back to the hydraulic oil tank through the unloading valve. When the steering action stops, the oil port L6, oil port R6 and return oil port T6 are connected to allow the oil to flow back to the hydraulic oil tank, thus relieving the pressure on the control ports a and b of the directional valve.

[0012] Furthermore, the pump is either a fixed displacement pump or a variable displacement pump.

[0013] The beneficial effects achieved by this invention are as follows: This invention provides a hydraulic system with both electronic control and steering wheel steering. When the loader is traveling at higher speeds, the steering wheel can be used to control the steering, offering excellent fine-tuning. When the loader is working or traveling at lower speeds, electronic steering can be used, making operation easier and reducing fatigue. When both controls are used simultaneously, the steering valve internally controls the output only for steering wheel control, prioritizing steering wheel steering and avoiding operational conflicts. If the electronic steering malfunctions, the output is cut off, but steering wheel steering remains unaffected, allowing continued steering control and improving steering safety. Attached Figure Description

[0014] Figure 1 A control principle diagram of a hydraulic system with electronic control and steering wheel steering provided for an embodiment of the present invention; Figure 2 A control principle diagram of the steering valve in a hydraulic system with electronic control and steering wheel steering, provided for an embodiment of the present invention; In the diagram, 1-Priority valve; 2-Steering valve; 3-Steering gear; 4-Reversing valve; 5-Steering cylinder; 6-Unloading valve; 7-Pump; 8-Hydraulic oil tank; 21-Signal selection valve; 22-Steering main valve; 23-Shut-off valve; 24-Left turn solenoid valve; 25-Right turn solenoid valve; 26-Pilot solenoid valve; 27-Shut-off control valve; 28-Pressure reducing valve. Detailed Implementation

[0015] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The embodiments described below with reference to the accompanying drawings are illustrative and intended to explain the present invention, and should not be construed as limiting the present invention.

[0016] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "end", "bottom", "side", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation. Therefore, they should not be construed as limiting this invention.

[0017] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "installation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a direct connection, or a connection through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances.

[0018] Secondly, the term "an embodiment" or "embodiment" as used in this invention refers to a specific feature, structure, or characteristic that can be included in at least one implementation of this invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments.

[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0020] Example 1, referring to Figure 1 This is the first embodiment of the invention, which provides a hydraulic system with electronic control and steering wheel, including a priority valve 1, a steering valve 2, a steering gear 3, a reversing valve 4, a steering cylinder 5, an unloading valve 6, a pump 7, and a hydraulic oil tank 8. Specifically, the oil inlet of pump 7 is connected to hydraulic oil tank 8, and the oil outlet is connected to the oil inlet P1 of priority valve 1; The oil outlet CF of priority valve 1 is simultaneously connected to the oil inlet P2 of steering valve 2, the oil inlet P3 of steering gear 3, and the oil inlet P4 of reversing valve 4. Priority valve 1's outlet EF is connected to hydraulic oil tank 8; Priority valve 1 port LS1 is simultaneously connected to steering valve 2 port LS2 and unloading valve 6 control port LS6; Priority valve 1's return port L1 is connected to hydraulic oil tank 8; The oil outlet CR of steering valve 2 is simultaneously connected to the control port a of reversing valve 4 and the oil port R6 of unloading valve 6. The oil outlet CL of steering valve 2 is simultaneously connected to the control port b of reversing valve 4 and the oil port L6 of unloading valve 4. The steering valve 2 oil port LS is connected to the steering gear 3 signal port LS3; The return port T2 of steering valve 2 is connected to the hydraulic oil tank 8; The oil outlet R3 of steering gear 3 is connected to the oil outlet R2 of steering valve 2, and the oil outlet L3 of steering gear 3 is connected to the oil outlet L2 of steering valve 2. The oil return port T3 of steering gear 3 is connected to the hydraulic oil tank 8. The unloading valve 6 returns oil port T6 to the hydraulic oil tank 8; The oil port A and oil port B of the reversing valve 4 are respectively connected to the rod chamber and rodless chamber of the steering cylinder 5; The return port T4 of the directional valve 4 is connected to the hydraulic oil tank 8.

[0021] It should be noted that pump 7 can be either a fixed displacement pump or a variable displacement pump.

[0022] In one embodiment, the outlet EF of the priority valve 1 can also be connected to other hydraulic systems to provide oil to those systems.

[0023] See Figure 2 In one embodiment, the steering valve 2 includes a signal selection valve 21, a steering master valve 22, a shut-off valve 23, a left-turn solenoid valve 24, a right-turn solenoid valve 25, a pilot solenoid valve 26, a shut-off control valve 27, and a pressure reducing valve 28.

[0024] The oil port P2 of steering valve 2 is simultaneously connected to the inlet P0 of steering master valve 22 and the oil port K0 of pressure reducing valve 28; The oil outlet A0 of the steering main valve 22 is connected to the oil inlet A1 of the shut-off valve 23, and the oil outlet B0 of the steering main valve 22 is connected to the oil inlet B1 of the shut-off valve 23. The return port T0 of the steering master valve 22 is connected to the return port T2 of the steering valve 2; The signal feedback port L0 of the steering master valve 22 is simultaneously connected to the spring chamber control port L2 of the signal selection valve 21 and the oil inlet port L1 of the shut-off valve 23; The control port a0 of the steering master valve 22 is simultaneously connected to the oil outlet a1 of the right turn solenoid valve 25 and the spring chamber control port a2 of the right turn solenoid valve 25. The control port b0 of the steering master valve 22 is simultaneously connected to the oil outlet b1 of the left turn solenoid valve 24 and the spring chamber control port b2 of the left turn solenoid valve 24. The oil outlet A2 of the shut-off valve 23 is simultaneously connected to the oil outlet R2 and the oil outlet CR of the steering valve 2. The oil outlet B2 of the shut-off valve 23 is simultaneously connected to the oil outlet L2 and the oil outlet CL of the steering valve 2. The oil outlet O1 of the shut-off valve 23 and the oil return port T7 of the spring chamber of the shut-off valve 23 are simultaneously connected to the oil return port T2 of the steering valve 2. The shut-off valve 23 controls the oil port K7, which is simultaneously connected to the oil outlet K6 of the pilot solenoid valve 26, the oil inlet K8 of the left-turn solenoid valve 24, and the oil inlet K9 of the right-turn solenoid valve 25. The return port O2 of the left-turn solenoid valve 24 and the return port O3 of the right-turn solenoid valve 25 are simultaneously connected to the return port T2 of the steering valve 2. The oil outlet K1 of the pressure reducing valve 28 is connected to both the control oil port K2 of the pressure reducing valve 28 and the oil inlet K3 of the cut-off control valve 27. The spring cavity return port O7 of the pressure reducing valve 28 is connected to the return port T2 of the steering valve 2. The oil outlet K4 of the cut-off control valve 27 is connected to the oil inlet K5 of the pilot solenoid valve 26. The control oil port L6 of the cut-off control valve 27 is simultaneously connected to the oil outlet L4 of the signal selection valve 21 and the oil port LS of the steering valve 2. The return oil port O5 of the cut-off control valve 27 and the spring cavity return oil port O6 of the cut-off control valve 27 are simultaneously connected to the return oil port T2 of the steering valve 2. The return port O3 of the pilot solenoid valve 26 and the return port O4 of the spring chamber of the pilot solenoid valve 26 are simultaneously connected to the return port T2 of the steering valve 2. The oil inlet L3 of the signal selection valve 21 and the control oil inlet L5 of the signal selection valve 21 are simultaneously connected to the oil inlet LS2 of the steering valve 2.

[0025] Example 2, the second embodiment of the present invention provides a control method for a hydraulic system with electronic control and steering wheel steering based on the above embodiments, as detailed below: 1. No steering action is performed: That is, the steering mechanism is not operated; steering gear 3, left-turn solenoid valve 24, and right-turn solenoid valve 25 are all in the standby position. Figure 1 The position is shown. Steering gear 3 has no action signal. Steering gear 3 signal port LS3 is connected to steering gear 3 return port T3, which is connected to the hydraulic oil tank 8. Left turn solenoid valve 24 and right turn solenoid valve 25 have no action signal. The control pressure at both ends of steering master valve 22 is connected to the return port T2 of steering valve 2 through left turn solenoid valve 24 and right turn solenoid valve 25, which is connected to the hydraulic oil tank 8. Steering master valve 22 is in the neutral position. The signal feedback port L0 of steering master valve 22 is connected to the return port T0 of steering master valve 22 through the inside of steering master valve 22, which is connected to the oil port T2 of steering valve 2, which is connected to the hydraulic oil tank 8. Pump 7 outputs oil to the inlet port P1 of priority valve 1, and flows out from port CF through the internal oil passage of priority valve 1. Since steering gear 3 and steering master valve 22 are both in the neutral position, the oil at port CF of priority valve 1 is sealed by steering gear 3 port P3 and steering master valve 22 port P0. Steering valve 2 has no output at outlet CR and port CL. With directional valve 4 in the neutral position, its inlet P4 also blocks the output of priority valve 1's outlet CF. Simultaneously, directional valve 4 disconnects outlets A and B, keeping steering cylinder 5 stationary. At this time, the pressure of priority valve 1's outlet CF is simultaneously transmitted to the control ports at both ends of the priority valve 1's valve core. The control oil in the priority valve 1's spring chamber flows out through damping from outlet LS1, enters through steering valve 2's outlet LS2, and simultaneously enters the inlet L3 and control port L5 of signal selection valve 21. Since the outlet L4 of signal selection valve 21 connects to the signal port LS3 of steering gear 3 via steering valve 2's outlet LS, the oil flows back to the hydraulic tank 8. The control port L2 of signal selection valve 21's spring chamber connects to the return port T0 of steering master valve 22 via its signal port L0, and flows back to the hydraulic tank 8 through steering valve 2's return port T2. As pump 7 outputs oil, the pressure gradually increases due to the sealed port CF of priority valve 1. This pressure, transmitted to control port 5 of signal selection valve 21, pushes the valve to switch to the lower position. Oil from port LS1 of priority valve 1 can then flow back to the hydraulic tank 8 via signal selection valve 21 and steering gear 3. At this time, the spring chamber of priority valve 1 controls the oil flow, creating a pressure difference with port CF. The control pressure on the right side of priority valve 1 remains the same as the pressure at port CF, pushing the valve core of priority valve 1 to the right position. Oil output from pump 7 flows back to the hydraulic tank 8 through port EF of priority valve 1. The vehicle remains in its current state without steering.

[0026] 2. When turning the steering wheel alone: ​​both the left-turn solenoid valve 24 and the right-turn solenoid valve 25 are in the standby position, i.e. Figure 1 As shown in the diagram, the left-turn solenoid valve 24 and the right-turn solenoid valve 25 have no operating signal. The control pressure at both ends of the steering master valve 22 is connected to the return port T2 of the steering valve 2 through the left-turn solenoid valve 24 and the right-turn solenoid valve 25, which in turn connects to the hydraulic oil tank 8. The steering master valve 22 is in the neutral position. The signal feedback port L0 of the steering master valve 22 is connected to the return port T0 of the steering master valve 22 through the inside of the steering master valve 22, which is connected to the oil port T2 of the steering valve 2, and then to the hydraulic oil tank 8. When steering gear 3 turns, the steering load is connected to the steering load via signal port LS3. The hydraulic fluid at signal port LS1 of priority valve 1 is connected to signal port LS3 of steering gear 3 via signal selection valve 21, establishing steering load pressure. The hydraulic fluid in the spring chamber of priority valve 1 also establishes pressure, allowing the main valve core of priority valve 1 to switch to the left position. At the same time, the pressure at the signal port of priority valve 1 is transmitted to the control port LS6 of unloading valve 6, causing unloading valve 6 to switch to the left position. Unloading valve ports L6 and R6 are blocked, preventing the hydraulic fluid from flowing back to the hydraulic tank 8 through unloading valve 6. The pump 7 outputs oil through the port CF of the priority valve 1 into the inlet P3 of the steering gear 3. When turning left, the oil flows out from the outlet L3 of the steering gear 3, through the port L2 of the steering valve 2 to the port CL of the steering valve 2, and then through the control port b of the reversing valve 4 to control the reversing valve 4 to reverse. The oil through the port CF of the priority valve 1 flows out from the port A of the reversing valve 4 through the port P4 of the reversing valve 4, causing the steering cylinder 5 to retract and drive the whole vehicle to turn left.

[0027] When turning right, the oil flows out from the outlet R3 of the steering gear 3, through the oil port R2 of the steering valve 2 to the oil port CR of the steering valve 2, and then through the control port a of the reversing valve 4 to control the reversing valve 4 to reverse. The oil at the oil port CF of the priority valve 1 flows out from the oil port B of the reversing valve 4 through the oil port P4 of the reversing valve 4, causing the steering cylinder 5 to extend and drive the whole vehicle to turn right.

[0028] When the steering wheel stops turning, steering gear 3 stops turning. The signal port LS3 of steering gear 3 connects to the return port T3 of steering gear 3, which in turn connects to the hydraulic oil tank 8. The oil port LS1 of priority valve 1 enters the inlet port L3 and control port L5 of signal selection valve 21 through the oil port LS2 of steering valve 2. Since the outlet port L4 of signal selection valve 21 connects to the signal port LS3 of steering gear 3 through the oil port LS of steering valve 2, the oil flows back to the hydraulic oil tank 8. The spring chamber control port L2 of signal selection valve 21 connects to the return port T0 of steering master valve 22 through the signal port L0 of steering master valve 22, and the oil flows back to the hydraulic oil tank 8 through the return port T2 of steering valve 2. The control port LS6 of the unloading valve 6 is also connected to the oil port LS2 of the steering valve 2, which in turn connects to the signal port LS3 of the steering gear 3, and then to the return oil port T3 of the steering gear 3, flowing back to the hydraulic oil tank 8. Under the action of the spring, the unloading valve 6 returns to the right position, connecting the unloading valve oil ports L6 and R6 to the return oil port T6, which in turn connects to the hydraulic oil tank 8. This unloads the pressure at the control ports a and b of the directional valve 4, causing the directional valve 4 to return to the neutral position. The cylinder 5 stops moving, and the vehicle stops steering. The priority valve 1 returns to the no-steering operation state, and the oil output from the pump 7 flows back to the hydraulic oil tank 8 through the priority valve 1 from the oil port EF.

[0029] 3. When using only electronic steering: Without operating the steering mechanism, steering gear 3 is in the standby position. Figure 1As shown in the diagram. Steering gear 3 has no operating signal. Steering gear 3 signal port LS3 is connected to steering gear 3 return port T3, which in turn connects to the hydraulic oil tank 8. During electronic left steering, pilot solenoid valve 26 and left-turn solenoid valve 24 are energized. Pilot solenoid valve 26 is energized, switching to the upper position. Oil from steering valve port P2 flows through pressure reducing valve 28 to cut-off control valve 27. Cut-off control valve 27 control port L6 is connected to steering valve 2 port LS, and the oil flows back to the hydraulic oil tank 8 through steering gear 3. Therefore, cut-off control valve 27 remains in the lower position. The oil flowing through pressure reducing valve 28 passes through shut-off control valve 27 to the inlet K5 of pilot solenoid valve 26, and through the upper oil circuit of pilot solenoid valve 26 to the outlet K6 of pilot solenoid valve 26. At the same time, it connects to the control oil port K7 of shut-off valve 23, the inlet K8 of left-turn solenoid valve 24, and the inlet K9 of right-turn solenoid valve 25. Shut-off valve 23 switches to the left position under control pressure. Oil port A1 connects to oil port A2, oil port B1 connects to oil port B2, and oil port L1 is disconnected from oil port O1. When the left-turn solenoid valve 24 is energized, its inlet K8 connects to its outlet b1 and control port b2. The electromagnetic force of the left-turn solenoid valve 24 balances with the pressure in its control chamber and the spring force. Adjusting the pressure at control port b2 creates different output pressures, controlling the different positions of the steering master valve 22's valve core. This pressure is then established at the master valve control port b0, pushing the valve core to the right position. The steering master valve 22's signal port L0 connects to the steering load and transmits pressure to the spring control chamber port L2 of the signal selector valve 21. The oil at the priority valve 1 signal port LS1 connects to the signal selector valve 21 inlet L3. Sufficient pressure must be established to push the valve core of the signal selector valve 21 upwards, connecting the steering gear 3 signal port LS3 and flowing back to the hydraulic oil tank 8. The spring chamber of priority valve 1 also builds up pressure in the control oil, allowing the main valve core of priority valve 1 to switch to the left position. Simultaneously, the pressure at the signal port of priority valve 1 is transmitted to the control port LS6 of unloading valve 6, causing unloading valve 6 to switch to the left position. Unloading valve ports L6 and R6 are blocked, preventing oil from flowing back to the hydraulic tank 8 through unloading valve 6. The oil output from pump 7 enters the inlet port P0 of directional main valve 22 through port CF of priority valve 1, flows out from port B0 of directional main valve 22, flows out through port B2 of shut-off valve 23, connects to port CL of steering valve 2, and then controls the directional valve 4 to switch through control port b of directional valve 4. The oil at port CF of priority valve 1 flows out through port P4 of directional valve 4, causing steering cylinder 5 to retract and driving the vehicle to turn left.

[0030] When the electric right turn is activated, the pilot solenoid valve 26 and the right turn solenoid valve 25 are energized. They operate on the same principle but with opposite actions. Specifically, the pressure at control port a2 of the right turn solenoid valve 24 is adjusted to establish pressure at control port a0 of the steering main valve 22, pushing the valve core of the steering main valve 22 to the left position. The oil output from pump 7 enters the inlet port P0 of the reversing main valve 22 through the oil port CF of the priority valve 1, flows out from the outlet port A0, flows out through the oil port A2 of the shut-off valve 23, connects to the oil port CR of the steering valve 2, and controls the reversing valve 4 to switch direction through control port a of the reversing valve 4. The oil at the oil port CF of the priority valve 1 flows out from the oil port B of the reversing valve 4 through the oil port P4 of the reversing valve 4, causing the steering cylinder 5 to extend and drive the vehicle to turn right.

[0031] When the electronic steering is stopped, the left-turn solenoid valve 24 and the right-turn solenoid valve 25 are de-energized. The control pressure of the steering master valve 22 flows back to the hydraulic oil tank 8 through the left-turn solenoid valve 24 and the right-turn solenoid valve 25. The steering master valve 22 returns to the neutral position. The signal port L0 of the steering master valve 22 connects to the return port T0 of the steering master valve 22 through the internal connection of the steering master valve 22, and then connects to the oil port T2 of the steering valve 2, thus connecting to the hydraulic oil tank 8. The oil port LS1 of the priority valve 1 enters the inlet port L3 and the control port L5 of the signal selection valve 21 through the oil port LS2 of the steering valve 2. Since the outlet port L4 of the signal selection valve 21 connects to the signal port LS3 of the steering gear 3 through the oil port LS of the steering valve 2, the oil flows back to the hydraulic oil tank 8. The control port LS6 of the unloading valve 6 is also connected to the oil port LS2 of the steering valve 2, which in turn connects to the signal port LS3 of the steering gear 3, and then to the return oil port T3 of the steering gear 3, flowing back to the hydraulic oil tank 8. Under the action of the spring, the unloading valve 6 returns to the right position, connecting the unloading valve oil ports L6 and R6 to the return oil port T6, which in turn connects to the hydraulic oil tank 8. This unloads the pressure at the control ports a and b of the directional valve 4, causing the directional valve 4 to return to the neutral position. The cylinder 5 stops moving, and the vehicle stops steering. The priority valve 1 returns to the no-steering operation state, and the oil output from the pump 7 flows back to the hydraulic oil tank 8 through the priority valve 1 from the oil port EF.

[0032] 3. When steering wheel and electronic steering are activated simultaneously: Steering gear 3 turns, signal port LS3 of steering gear 3 connects to the steering load, and steering valve 2's oil port LS also establishes a steering load. Simultaneously, signal selection valve 21's oil port L4 and cut-off control valve 27's control oil port L6 are connected. Under the action of the control port, cut-off control valve 27 switches to its upper position, connecting its oil port K4 to its return oil port O5. This prevents cut-off valve 23, left-turn solenoid valve 24, and right-turn solenoid valve 25 from receiving control oil, thus preventing electronic steering. This achieves the function of prioritizing steering wheel steering when steering wheel and electronic steering are activated simultaneously.

[0033] 4. When the electronic steering malfunctions: When the electronic steering malfunctions, the power supply to the pilot solenoid valve 26 can be cut off, causing it to operate in the lower position. This connects the oil outlet K6 of the pilot solenoid valve 26 to the oil return port O3, preventing the shut-off valve 23, left-turn solenoid valve 24, and right-turn solenoid valve 25 from receiving control oil and thus preventing electronic steering. Furthermore, even if the steering master valve 22 is stuck in the reversing position, the steering wheel priority function can still be used to disable the electronic steering function through the shut-off valve, ensuring that the electronic steering does not affect the steering wheel and improving steering safety.

[0034] It should be noted that when the flow rate of the steering system is low, the directional valve and the unloading valve can be eliminated, and the steering valve can directly control the steering cylinder.

[0035] 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 hydraulic system with electronic control and steering wheel steering, comprising a priority valve, a steering gear, a directional valve, a steering cylinder, a pump, and a hydraulic oil tank, wherein the pump inlet is connected to the hydraulic oil tank, and the pump outlet is connected to the priority valve inlet P1; the priority valve outlet CF is connected to the steering gear inlet P3 and the directional valve inlet P4; the directional valve outlet A and outlet B are respectively connected to the rod-side chamber and rodless chamber of the steering cylinder; the priority valve outlet EF, the steering gear return port T3, and the directional valve return port T4 are all connected to the hydraulic oil tank; characterized in that, It also includes the steering valve; The steering valve inlet P2 is connected to the priority valve outlet CF; the steering valve outlet CR is connected to the directional valve control port a; the steering valve outlet CL is connected to the directional valve control port b; the steering valve port LS is connected to the steering gear signal port LS3; the steering valve port LS2 is connected to the priority valve port LS1; the steering valve port R2 is connected to the steering gear outlet R3; the steering valve port L2 is connected to the steering gear outlet L3; and the steering valve return port T2 is connected to the hydraulic oil tank. The steering valve includes a signal selection valve, a steering main valve, a shut-off valve, a left-turn solenoid valve, a right-turn solenoid valve, a pilot solenoid valve, a shut-off control valve, and a pressure reducing valve. The steering valve inlet P2 is simultaneously connected to the steering main valve inlet P0 and the pressure reducing valve inlet K0. The oil outlet A0 of the steering main valve is connected to the oil inlet A1 of the shut-off valve, and the oil outlet B0 of the steering main valve is connected to the oil inlet B1 of the shut-off valve. The return port T0 of the steering main valve is connected to the return port T2 of the steering valve. The steering main valve signal feedback port L0 is simultaneously connected to the spring chamber control port L2 of the signal selection valve and the oil inlet port L1 of the shut-off valve. The steering main valve control port a0 is simultaneously connected to the oil outlet port a1 of the right turn solenoid valve and the spring chamber control port a2 of the right turn solenoid valve. The steering main valve control port b0 is simultaneously connected to the oil outlet b1 of the left turn solenoid valve and the spring chamber control port b2 of the left turn solenoid valve. The shut-off valve outlet A2 is simultaneously connected to the steering valve outlet R2 and the steering valve outlet CR; The shut-off valve outlet B2 is simultaneously connected to the steering valve outlet L2 and the steering valve outlet CL; The oil outlet port O1 of the shut-off valve and the oil return port T7 of the shut-off valve spring cavity are simultaneously connected to the oil return port T2 of the steering valve. The shut-off valve control port K7 is simultaneously connected to the outlet port K6 of the pilot solenoid valve, the inlet port K8 of the left-turn solenoid valve, and the inlet port K9 of the right-turn solenoid valve. The oil outlet K1 of the pressure reducing valve is simultaneously connected to the control oil outlet K2 of the pressure reducing valve and the oil inlet K3 of the shut-off control valve. The oil outlet K4 of the cut-off control valve is connected to the oil inlet K5 of the pilot solenoid valve, and the control oil port L6 of the cut-off control valve is simultaneously connected to the oil outlet L4 of the signal selection valve and the oil port LS of the steering valve. The oil inlet L3 and the control oil inlet L5 of the signal selection valve are simultaneously connected to the oil inlet LS2 of the steering valve. The oil return port O2 of the left-turn solenoid valve, the oil return port O3 of the right-turn solenoid valve, the oil return port O7 of the spring cavity of the pressure reducing valve, the oil return port O5 and the oil return port O6 of the cut-off control valve, and the oil return port O3 and the oil return port O4 of the pilot solenoid valve are all connected to the oil return port T2 of the steering valve. When the directional valve is used for steering wheel turning and stopping steering, it controls the oil flowing through the directional valve to flow directly back to the hydraulic oil tank; and when used for electronic steering, it controls the oil output by the priority valve to flow out through the oil outlet of the steering valve, controls the directional valve connected thereto to switch direction, and causes the steering cylinder to move.

2. A hydraulic system with electric control and steering wheel steering according to claim 1, characterized in that, When there is no steering action, the steering gear signal port LS3 is connected to the return port T3, the left turn solenoid valve outlet port b1 and return port O2 are connected, and the right turn solenoid valve outlet port a1 and return port O3 are connected. When the reversing valve is in the neutral position, the reversing valve disconnects oil outlet A and oil outlet B, and the steering cylinder remains stationary.

3. A hydraulic system with electric control and steering wheel steering according to claim 1, characterized in that, When the steering wheel is turned independently, the oil outlet b1 and oil return port O2 of the left-turn solenoid valve are connected, and the oil outlet a1 and oil return port O3 of the right-turn solenoid valve are connected. The steering gear is controlled to turn. The steering gear signal port LS3 is connected to the steering load. The pump output oil enters the steering gear inlet port P3 through the priority valve port CF. When turning left, the oil flows out from the steering gear outlet port L3, through the steering valve port L2 to port CL, and controls the reversing valve to switch direction through the reversing valve control port b. The oil at the priority valve port CF flows out from port A through the reversing valve port P4, causing the steering cylinder to retract and driving the vehicle to turn left. When turning right, the oil flows out from the steering gear outlet port R3, through the steering valve port R2 to port CR, and controls the reversing valve to switch direction through the reversing valve control port a. The oil at the priority valve port CF flows out from port B through the reversing valve port P4, causing the steering cylinder to extend and driving the vehicle to turn right.

4. A hydraulic system with electric control and steering wheel steering according to claim 1, characterized in that, When the steering is controlled electronically, the steering gear signal port LS3 is connected to the oil return port T3. When the electric left turn is activated, the pilot solenoid valve and the left turn solenoid valve are energized, connecting the inlet K5 and outlet K6 of the pilot solenoid valve, and connecting the inlet K8 of the left turn solenoid valve to the outlet b1 and control port b2. This causes the shut-off valve to switch to the left position under control pressure, connecting port A1 to port A2, port B1 to port B2, and port L1 to port O1. The pressure at the control port b2 of the left turn solenoid valve is adjusted to build pressure at the control port b0 of the steering main valve, pushing the steering main valve spool to the right position. The pump output oil enters the main directional valve inlet P0 through the priority valve port CF, flows out from the outlet B0, flows out through the shut-off valve port B2, connects to the steering valve port CL, and controls the directional valve to switch direction through the directional valve control port b. The oil in the priority valve port CF flows out from the directional valve port A through the directional valve port P4, causing the steering cylinder to retract and drive the vehicle to turn left. When the electric right turn is activated, the pilot solenoid valve and the right turn solenoid valve are energized, so that the oil inlet K5 and oil outlet K6 of the pilot solenoid valve are connected, and the oil inlet K9 of the right turn solenoid valve is connected to the oil outlet a1 and the control port b2. The pressure of the control port a2 of the right turn solenoid valve is adjusted, and the pressure is established at the control port a0 of the steering main valve, which pushes the steering main valve core to work in the left position. The pump output oil enters the inlet P0 of the main directional valve through the priority valve port CF, flows out from the outlet A0, flows out through the shut-off valve port A2, connects to the steering valve port CR, and controls the directional valve to switch direction through the directional valve control port a. The oil in the priority valve port CF flows out from the directional valve port B through the directional valve port P4, causing the steering cylinder to extend and drive the vehicle to turn right.

5. A hydraulic system with electric control and steering wheel steering according to claim 1, characterized in that, When the left-turn solenoid valve and the right-turn solenoid valve are energized, they control the steering gear to turn. The steering gear signal port LS3 is connected to the steering load, and the steering valve oil port LS is also connected to the steering load. The steering valve oil port LS is simultaneously connected to the oil outlet L4 of the signal selection valve and the control oil port L6 of the cut-off control valve. Under the action of the control oil port, the cut-off control valve connects the oil port K4 to the return oil port O5, so that the cut-off valve, the left-turn solenoid valve and the right-turn solenoid valve do not receive control oil and cannot achieve electric steering.

6. A hydraulic system with electronic control and steering wheel steering according to claim 1, characterized in that, When the electronic steering malfunctions, the power supply to the pilot solenoid valve is disconnected, connecting the oil outlet K6 of the pilot solenoid valve to the oil return port O3. This prevents the shut-off valve, left-turn solenoid valve, and right-turn solenoid valve from receiving control oil, thus preventing electronic steering from being achieved.

7. A hydraulic system with electric control and steering wheel steering according to claim 1, characterized in that, The hydraulic system also includes an unloading valve; The priority valve port LS1 is simultaneously connected to the steering valve port LS2 and the unloading valve control port LS6; The oil outlet CR of the steering valve is simultaneously connected to the control port a of the reversing valve and the oil port R6 of the unloading valve. The oil outlet CL of the steering valve is simultaneously connected to the control port b of the reversing valve and the oil port L6 of the unloading valve. The unloading valve return port T6 is connected to the hydraulic oil tank; The unloading valve is used to switch to the left position after sensing the pressure transmitted by the priority valve, and the unloading valve oil port L6 and unloading valve oil port R6 are blocked so that the oil cannot flow back to the hydraulic oil tank through the unloading valve. When the steering action stops, the oil port L6, oil port R6 and return oil port T6 are connected to allow the oil to flow back to the hydraulic oil tank, thus relieving the pressure on the control ports a and b of the directional valve.

8. A hydraulic system with electric control and steering wheel steering according to claim 1, characterized in that, The pump is either a fixed displacement pump or a variable displacement pump.

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