Harvester hydraulic control system and method and harvester

Abstract

The invention provides a harvester hydraulic control system and method and a harvester. A hydraulic control system of a harvester comprises a walking HST, a steering valve, a gearbox, a control valve, a working device, a working pump, an engine, a controller and a hydraulic oil tank, and the steering valve, the gearbox, the control valve, the working device, the working pump, the engine, the controller and the hydraulic oil tank are used for achieving fine adjustment steering, differential steering, single-side braking and pivot steering. The engine is in transmission connection with the walking HST and the working pump, the working pump, the walking HST and the control valve are all connected with the hydraulic oil tank, the control valve is connected with the working pump, the left chassis lifting oil cylinder and the right chassis lifting oil cylinder are both connected with the control valve, the walking HST and the steering valve are both installed on the gearbox, the walking HST is connected with the gearbox, and the steering valve is connected with the steering valve. The gearbox is in transmission connection with the walking HST, and the controller is connected with the walking HST, the conversion valve and the control valve.

Description

Technical Field

[0001] This invention relates to the field of hydraulic systems for harvesters, and more particularly to a hydraulic control system, method, and harvester for a harvester. Background Technology

[0002] Currently, tracked harvesters generally use single-sided braking and steering gearboxes, resulting in high steering loads, uneven steering, and poor maneuverability. A small number of models use wheel-side hydraulic motors or hydraulic motors + reducers to drive the tracks, which are costly and involve more piping. The chassis are mostly rigid, making them less adaptable to working on slopes, deep muddy fields, and traversing ridges smoothly. Especially with rising labor costs, agricultural cooperatives, large-scale farmers, and major farms are demanding higher operating efficiency and more intelligent, labor-saving tracked harvesters. Traditional tracked harvesters lack improved handling comfort, walking and steering stability, making it difficult to simultaneously meet the needs of different users and different terrain conditions, and failing to achieve true lightweight design, high adaptability, and high cost-effectiveness.

[0003] Current tracked harvesters generally use a single-sided braking and steering gearbox, while unmanned tracked harvesters use wheel-side hydraulic motors or hydraulic motors + reducers to drive the tracks. The chassis is mostly rigid, and navigation and speed are matched to adapt to the unmanned driving system. Single-sided braking and steering gearboxes result in high steering load, uneven steering, and poor maneuverability; wheel-side hydraulic motors or hydraulic motors + reducers drive the tracks, resulting in heavy weight, high cost, and numerous piping issues; rigid chassis are poorly suited for working on slopes, in deep muddy fields, and for smooth crossing of embankments. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a hydraulic control system, method and harvester for a harvester.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A hydraulic control system for a harvester includes: a travel HST, a steering valve for realizing fine-tuning steering, differential steering, single-sided braking and stationary steering, a gearbox, a control valve, a working device, a working pump, an engine, a controller, and a hydraulic oil tank. The working device includes: a left chassis lifting cylinder and a right chassis lifting cylinder. The engine is respectively drivenly connected to the travel HST and the working pump. The working pump, the travel HST, and the control valve are all connected to the hydraulic oil tank through pipelines. The control valve is connected to the working pump through a pipeline. The left chassis lifting cylinder and the right chassis lifting cylinder are both connected to the control valve through pipelines. The travel HST and the steering valve are both mounted on the gearbox. The travel HST is connected to the gearbox through a pipeline. The gearbox is drivenly connected to the travel HST. The controller is respectively connected to the travel HST, the steering valve, and the control valve.

[0006] The beneficial effects of adopting the technical solution of this invention are: by using the HST (Hardware Steering) system with a steering valve, weight, load, and cost are reduced. The chassis can be raised or lowered, and can turn on the spot with a small turning radius, thus providing better adaptability for operations on slopes, in deep muddy fields, and for smooth crossing of embankments. This solves the problems of high steering load, poor flexibility, heavy weight, and high cost associated with existing technologies, while also addressing the poor adaptability for operations on slopes, in deep muddy fields, and for smooth crossing of embankments.

[0007] Furthermore, the controller is connected to a first pressure sensor for detecting the forward pressure of the traveling HST, a second pressure sensor for detecting the reverse pressure of the traveling HST, a first angle sensor for detecting the left chassis angle, a second angle sensor for detecting the right chassis angle, a vehicle posture sensor for detecting the vehicle posture, a temperature sensor for detecting the oil temperature, a Beidou navigation system, and a speed sensor for detecting the vehicle speed. The first pressure sensor and the second pressure sensor are respectively connected to the pressure measuring port of the traveling HST through pipelines.

[0008] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: Real-time matching between the chassis lifting angle sensor and the vehicle posture sensor, and real-time matching between vehicle speed and Beidou navigation, improves work quality and efficiency, meeting user needs for comfortable operation, smooth steering, high cost-effectiveness, and high adaptability. The mechanical structure is simple, energy-efficient, and lightweight. The controller reads vehicle speed through a speed sensor and walking pressure through a first and second pressure sensor. Through a walking control strategy, it controls the displacement of the walking pump and walking motor of the walking HST. Low pressure switches to a smaller displacement walking motor, and vice versa; low speed switches to a larger displacement walking pump, and vice versa, achieving automatic vehicle speed control. During short-distance relocation, the walking motor can be automatically or manually switched to a smaller displacement, improving work efficiency and saving energy. By combining Beidou navigation and steering valves, unmanned automatic control is achieved. The controller reads signals from the vehicle body attitude sensor to control the left and right chassis lifting cylinders. It also reads signals from the first and second angle sensors to achieve automatic leveling closed-loop control of the chassis lifting mechanism. Manual control is possible under special operating conditions to improve work comfort and maneuverability. The controller reads the oil temperature from the temperature sensor and sends it to the ECU. When the set temperature is reached, the Y17 valve of the fan backflush valve is energized, executing the fan backflush command. If the oil temperature does not reach the set value, backflush is performed at set time intervals. If the oil temperature is below a certain set value, the fan backflush valve does not operate and does not perform the reversing action.

[0009] Further, the travel HST includes: a travel pump, a replenishing overflow valve, a first high-pressure overflow valve, a second high-pressure overflow valve, a replenishing pump, a steering pump, a travel motor, a variable displacement motor control valve, and a variable displacement pump control valve. The travel pump is drivenly connected to the engine, and is also drivenly connected to the replenishing pump and the steering pump. The replenishing overflow valve is connected to both the variable displacement motor control valve and the variable displacement pump control valve. The first high-pressure overflow valve and the second high-pressure overflow valve are both connected via pipelines to the travel pump, the hydraulic tank, the steering pump, and the travel motor, respectively. The steering pump is connected via pipelines to both the gearbox and the steering valve. The travel motor is drivenly connected to the gearbox. The variable displacement motor control valve is connected via pipelines to both the travel motor and the variable displacement pump control valve, and the variable displacement pump control valve is connected via pipelines to the travel pump.

[0010] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the travel and steering system is working, the travel HST is a closed system. A replenishing pump and a steering pump are connected in series on the pump shaft of the travel HST. The replenishing pump draws oil from the hydraulic oil tank through the second suction filter, and the oil enters the travel HST to complete control actions and replenish leaks. The steering pump draws oil from the gearbox housing through the steering suction filter and the steering radiator, and then enters the steering valve through the steering filter. The travel pump can achieve stepless displacement control through a variable pump control valve, and the travel motor can achieve stepless or multi-point displacement control through a variable motor control valve. The controller reads vehicle speed through a speed sensor and travel pressure through a first and second pressure sensor. Using a travel control strategy, it controls the displacement of the travel pump and travel motor of the travel HST. Low pressure switches to a smaller travel motor displacement, and vice versa. Low speed switches to a larger travel pump displacement, and vice versa, achieving automatic vehicle speed control. During short-distance relocation, the travel motor displacement can be automatically or manually switched to a smaller displacement, improving work efficiency and saving energy. By integrating with BeiDou navigation and steering valves, it achieves unmanned automatic control.

[0011] Furthermore, the oil replenishment pump is connected to a fan backflush valve or a proportional solenoid valve via a pipeline. The fan backflush valve or the proportional solenoid valve is connected to a hydraulic commutator fan for cooling the engine and an ECU. The hydraulic commutator fan is located at the end of the engine. The ECU is connected to the controller. The oil replenishment overflow valve is connected to the fan backflush valve or the proportional solenoid valve via a pipeline.

[0012] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the travel steering system is working, the travel HST is a closed system. A replenishing pump and a steering pump are connected in series on the pump shaft of the travel HST. After the replenishing pump draws oil from the hydraulic oil tank through the second suction filter, a portion of the oil enters the travel HST to complete control actions and replenish leaks, while the other portion enters the hydraulic reversing fan through the fan backflush valve to realize the reversing of the hydraulic reversing fan and complete the backflush action. The steering pump draws oil from the gearbox housing through the steering suction filter and steering radiator, and enters the steering valve through the steering filter. The controller reads the oil temperature through a temperature sensor and sends it to the ECU. When the set temperature value is reached, Y17 of the fan backflush valve is energized, executing the fan backflush command. When the oil temperature does not reach the set value, the backflush action is executed according to the set time interval. When the oil temperature is lower than a certain set value, the fan backflush valve does not work and does not execute the reversing action. The fan backflush valve can be replaced with a proportional solenoid valve, with a flow meter added after the valve to collect the output flow signal. By controlling the output flow, stepless speed regulation control of the hydraulic reversing fan is achieved, saving energy and reducing consumption.

[0013] Further, the steering valve includes: an overflow valve, an unloading valve, a right clutch solenoid valve, a left clutch solenoid valve, a proportional pressure reducing valve, and a steering switching valve. The gearbox includes: a housing, a left clutch, a right clutch, a steering clutch, and a soft clutch. The overflow valve is connected to the housing, the travel HST, the unloading valve, and the right clutch solenoid valve via pipelines. The unloading valve is connected to the housing, the travel HST, and the right clutch solenoid valve via pipelines. The right clutch solenoid valve is connected to the left clutch solenoid valve, the steering switching valve, the housing, and the right clutch via pipelines. The left clutch solenoid valve is connected to the housing and the left clutch via pipelines. The proportional pressure reducing valve is connected to the housing, the steering switching valve, the left clutch, and the right clutch via pipelines. The steering switching valve is connected to the housing, the steering clutch, and the soft clutch via pipelines.

[0014] The beneficial effects of adopting the above-mentioned further technical solution are as follows: when not steering, the unloading valve Y1 is energized; when fine-tuning steering, the right clutch solenoid valve Y3 or the left clutch solenoid valve Y2 is energized; when differential steering, the proportional pressure reducing valve Y4 and the left clutch solenoid valve Y2 or the right clutch solenoid valve Y3 are energized; when braking on one side and turning in place, the proportional pressure reducing valve Y4, the steering switching valve Y5 and the left clutch solenoid valve Y2 or the right clutch solenoid valve Y3 are energized; when braking on one side, the steering clutch pressure is low and there is no power output.

[0015] Furthermore, the travel HST is an electronically controlled stepless speed-regulating travel HST, and the steering valve is an electronically controlled steering valve.

[0016] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The steering valve is electronically controlled, and in conjunction with the gearbox, it can achieve four steering modes: fine-tuning steering, differential steering, single-sided braking, and stationary steering, thus realizing the stationary steering function and adapting to various working conditions. The travel HST uses an electronically controlled stepless speed regulation method, and the travel pump can achieve stepless displacement control through a variable pump control valve, while the travel motor can achieve stepless or multi-point displacement control through a variable motor control valve.

[0017] Further, the control valve includes: a main relief valve, an enabling valve, a header priority valve, a header relief valve, a header rise proportional valve, a pressure compensator, a header fall proportional valve, a right chassis lift proportional valve, multiple hydraulic locks, a left chassis lift proportional valve, a reel control valve, and a grain unloading control valve. Both ends of the main relief valve and both ends of the enabling valve are connected to the working pump and the hydraulic tank respectively via pipelines. Port 1 of the header priority valve is connected to the working pump via a pipeline. Port 2 of the header priority valve is connected to the header rise proportional valve via a pipeline. Port 3 of the header priority valve is connected to the right chassis lift proportional valve, the left chassis lift proportional valve, the reel control valve, and the grain unloading control valve via pipelines. The grain control valve is connected, and the two ends of the header overflow valve are connected to the header priority valve and the hydraulic oil tank respectively through pipelines. The header descent proportional valve is connected to the hydraulic oil tank through the pressure compensator. The working device includes: a grain unloading cylinder, a reel cylinder, and a header cylinder. The grain unloading control valve is connected to the grain unloading cylinder through the hydraulic lock. The reel control valve is connected to the reel cylinder through the hydraulic lock. The left chassis lifting proportional valve is connected to the left chassis lifting cylinder through the hydraulic lock. The right chassis lifting proportional valve is connected to the right chassis lifting cylinder through the hydraulic lock. The header descent proportional valve and the header ascent proportional valve are connected to the header cylinder through pipelines.

[0018] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the working device is working, the working pump draws oil from the hydraulic oil tank through the first suction filter, and then enters the P port of the control valve through the first filter. When the working device is not working, the oil flows back to the hydraulic oil tank through the T port of the enable valve. When the working device is working, the enable valve is energized to switch functions. When the cutting platform is lifted, the oil flow is distributed by the cutting platform priority valve according to the opening of the cutting platform lifting proportional valve. The flow from port 2 of the cutting platform priority valve preferentially enters the cutting platform cylinder through the cutting platform lifting proportional valve to realize the lifting of the cutting platform. The remaining flow enters the subsequent working valve through port 3 of the cutting platform priority valve. The cutting platform cylinder can connect with the right side bottom... The lifting cylinders of the header, left chassis, reel, and unloading cylinders perform combined actions. When the header descends, the header descent proportional valve is energized, and the descent speed is controlled by the current-controlled valve opening. Oil flows back to the oil tank from port T through the header descent proportional valve and pressure compensator. The pressure compensator maintains a constant pressure difference across the header descent proportional valve, improving the stability of the header descent speed. When other working devices are operating and the header is not, all oil flows through port 3 of the header priority valve, through the right or left chassis lifting proportional valve, reel control valve, or unloading control valve, to the corresponding actuator to complete the corresponding action. The controller reads signals from the vehicle body attitude sensor to control the left and right chassis lifting cylinders. By reading signals from the first and second angle sensors, it achieves automatic leveling closed-loop control of the chassis lifting. Manual control is possible under special working conditions to improve operational comfort and maneuverability. Hydraulic locks are installed on the control valve oil lines corresponding to the right chassis lifting cylinder, left chassis lifting cylinder, reel cylinder, and unloading cylinder to prevent excessive static settlement.

[0019] Furthermore, a first filter is installed on the pipeline between the control valve and the working pump, and a first suction filter is installed on the pipeline between the working pump and the hydraulic oil tank; a first radiator, a second suction filter, a steering suction filter, and a steering radiator are installed on the pipeline between the travel HST and the hydraulic oil tank; a hydraulic oil tank breather is installed on the hydraulic oil tank; a gearbox breather is installed on the gearbox; and a steering filter is installed on the pipeline between the travel HST and the steering valve.

[0020] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the filter and oil suction filter are used to filter impurities in the oil, preventing impurities from entering the system and improving the stability and reliability of the system. The radiator is used to cool the oil and prevent it from overheating. The breather is used to allow ventilation between the oil tank and the gearbox and the outside environment.

[0021] In addition, the present invention also provides a harvester, including the harvester hydraulic control system described above.

[0022] In addition, the present invention also provides a hydraulic control method for a harvester. Based on the above-described hydraulic control system for a harvester, the hydraulic control method for a harvester includes: when the working device is working, the engine drives the working pump to draw oil from the hydraulic oil tank and deliver it to the control valve, and the controller controls the control valve to distribute the oil to the working device, so that the working device works; when traveling and turning, the engine drives the traveling HST to draw oil from the gearbox and deliver it to the steering valve, and the controller controls the steering valve to distribute the oil to the gearbox, so as to realize fine-tuning steering, differential steering, single-sided braking and stationary turning.

[0023] The advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is one of the structural schematic diagrams of the hydraulic control system for a harvester provided in an embodiment of the present invention.

[0026] Figure 2 This is a second schematic diagram of the hydraulic control system for a harvester provided in an embodiment of the present invention.

[0027] Figure 3 The third schematic diagram of the hydraulic control system for a harvester provided in an embodiment of the present invention.

[0028] Figure 4 The fourth schematic diagram of the hydraulic control system for a harvester provided in an embodiment of the present invention.

[0029] Figure 5 This is one of the schematic diagrams of the steering control action of the hydraulic control system of a harvester provided in an embodiment of the present invention.

[0030] Figure 6 This is the second schematic diagram of the steering control action of the hydraulic control system of the harvester provided in the embodiment of the present invention.

[0031] Figure 7 This is the third schematic diagram of the steering control action of the hydraulic control system of the harvester provided in the embodiment of the present invention.

[0032] Figure 8 The fourth schematic diagram of the steering control action of the hydraulic control system of the harvester provided in the embodiment of the present invention.

[0033] Reference numerals: 1. Traveling HST; 2. Steering valve; 3. Gearbox; 4. Control valve; 5. Unloading cylinder; 6. Reel cylinder; 7. First angle sensor; 8. Left chassis lifting cylinder; 9. Vehicle posture sensor; 10. Second angle sensor; 11. Right chassis lifting cylinder; 12. Cutting head cylinder; 13. Hydraulic reversing fan; 14. Fan backflush valve; 15. First filter; 16. Working pump; 17. First suction filter; 18. Engine; 19. ECU; 20. Controller; 21. Temperature sensor; 22. Beidou navigation; 23. First radiator; 24. Hydraulic oil tank; 25. Hydraulic oil tank breather; 26. Second suction filter; 27. Steering suction filter; 28. Steering radiator; 29. ​​Gearbox breather; 30. Steering filter; 31. Speed ​​sensor. 1-1. Travel pump; 1-2. Make-up oil relief valve; 1-3. First high-pressure relief valve; 1-4. Second high-pressure relief valve; 1-5. Make-up oil pump; 1-6. Steering pump; 1-7. Travel motor; 1-8. Variable displacement motor control valve; 1-9. Variable displacement pump control valve; 1-10. First pressure sensor; 1-11. Second pressure sensor; 2-1. Relief valve; 2-2. Unloading valve; 2-3. Right clutch solenoid valve; 2-4. Left clutch solenoid valve; 2-5. Proportional pressure reducing valve; 2-6. Steering switching valve; 3-1. Housing; 3-2. Left clutch; 3-3. Right clutch; 3-4. Steering clutch; 3-5. Soft clutch; 4-1. Main relief valve; 4-2. Enabling valve; 4-3. Header priority valve; 4-4. Header relief valve; 4-5. Header rise proportional valve; 4-6. Pressure compensator; 4-7. Header fall proportional valve; 4-8. Right side chassis lift proportional valve; 4-9. Hydraulic lock; 4-10. Left side chassis lift proportional valve; 4-11. Reel control valve; 4-12. Unloading control valve. Detailed Implementation

[0034] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments described are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0038] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0039] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0040] like Figures 1 to 4As shown, this embodiment of the invention provides a hydraulic control system for a harvester, including: a travel HST1, a steering valve 2 for fine-tuning steering, differential steering, single-sided braking, and stationary steering, a gearbox 3, a control valve 4, a working device, a working pump 16, an engine 18, a controller 20, and a hydraulic oil tank 24. The working device includes: a left chassis lifting cylinder 8 and a right chassis lifting cylinder 11. The engine 18 is connected to the travel HST1 and the working pump 16 respectively. The working pump 16, the travel HST1, and the... Control valve 4 is connected to the hydraulic oil tank 24 via pipelines. Control valve 4 is connected to the working pump 16 via pipelines. The left chassis lifting cylinder 8 and the right chassis lifting cylinder 11 are both connected to control valve 4 via pipelines. The travel HST1 and the steering valve 2 are both mounted on the gearbox 3. The travel HST1 is connected to the gearbox 3 via pipelines. The gearbox 3 is connected to the travel HST1 via transmission. The controller 20 is connected to the travel HST1, the steering valve 2, and the control valve 4 respectively.

[0041] The beneficial effects of adopting the technical solution of this invention are: by using the HST (Hardware Steering) system with a steering valve, weight, load, and cost are reduced. The chassis can be raised or lowered, and can turn on the spot with a small turning radius, thus providing better adaptability for operations on slopes, in deep muddy fields, and for smooth crossing of embankments. This solves the problems of high steering load, poor flexibility, heavy weight, and high cost associated with existing technologies, while also addressing the poor adaptability for operations on slopes, in deep muddy fields, and for smooth crossing of embankments.

[0042] The steering valve 2 is installed on the gearbox 3 and controls the engagement and disengagement of the various clutches in the gearbox 3 through the oil passage on the mounting surface.

[0043] The steering valve 2 can be connected to the travel HST1 via a pipeline. Specifically, the steering valve 2 is installed on one side of the gearbox 3, and the travel HST1 is installed on the other side. A steering pump is connected in series with the travel HST1, and the steering pump is connected to the steering valve 2 via a pipeline to supply oil to the steering valve 2.

[0044] like Figures 1 to 4As shown, the controller 20 is further connected to a first pressure sensor 1-10 for detecting the forward pressure of the HST1, a second pressure sensor 1-11 for detecting the backward pressure of the HST1, a first angle sensor 7 for detecting the left chassis angle, a second angle sensor 10 for detecting the right chassis angle, a vehicle posture sensor 9 for detecting the vehicle posture, a temperature sensor 21 for detecting the oil temperature, a Beidou navigation system 22, and a speed sensor 31 for detecting the vehicle speed. The first pressure sensor 1-10 and the second pressure sensor 1-11 are respectively connected to the pressure measuring port of the HST1 via pipelines.

[0045] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: Real-time matching between the chassis lifting angle sensor and the vehicle posture sensor, and real-time matching between vehicle speed and Beidou navigation, improves work quality and efficiency, meeting user needs for comfortable operation, smooth steering, high cost-effectiveness, and high adaptability. The mechanical structure is simple, energy-efficient, and lightweight. The controller reads vehicle speed through a speed sensor and walking pressure through a first and second pressure sensor. Through a walking control strategy, it controls the displacement of the walking pump and walking motor of the walking HST. Low pressure switches to a smaller displacement walking motor, and vice versa; low speed switches to a larger displacement walking pump, and vice versa, achieving automatic vehicle speed control. During short-distance relocation, the walking motor can be automatically or manually switched to a smaller displacement, improving work efficiency and saving energy. By combining Beidou navigation and steering valves, unmanned automatic control is achieved. The controller reads signals from the vehicle body attitude sensor to control the left and right chassis lifting cylinders. It also reads signals from the first and second angle sensors to achieve automatic leveling closed-loop control of the chassis lifting mechanism. Manual control is possible under special operating conditions, improving work comfort and maneuverability. The controller reads the oil temperature from the temperature sensor and sends it to the ECU. When the set temperature is reached, Y17 of the fan backflush valve 14 is energized, executing the fan backflush command. If the oil temperature does not reach the set value, backflushing is performed at set time intervals. If the oil temperature is below a certain set value, the fan backflush valve 14 does not operate and does not perform the reversing action.

[0046] The Beidou Navigation System 22 is used for navigation, providing trajectory input for autonomous driving. It is installed on the outer side of the roof of the vehicle, near the driver's cab. When the navigation system inputs a trajectory, such as a desire to drive in a straight line, and indicates a deviation, the steering valve 2 actuates to correct the driving trajectory. The automatic control method involves planning a route based on a user-preset trajectory, using the navigation system as input, and adjusting the vehicle's steering in real time according to the input to match the driving trajectory.

[0047] like Figures 1 to 4As shown, the travel HST1 further includes: a travel pump 1-1, a fuel replenishment overflow valve 1-2, a first high-pressure overflow valve 1-3, a second high-pressure overflow valve 1-4, a fuel replenishment pump 1-5, a steering pump 1-6, a travel motor 1-7, a variable displacement motor control valve 1-8, and a variable displacement pump control valve 1-9. The travel pump 1-1 is driven by the engine 18, and is driven by the fuel replenishment pump 1-5 and the steering pump 1-6. The fuel replenishment overflow valve 1-2 is connected to the variable displacement motor control valve 1-8 and the variable displacement pump control valve 1-9 respectively. The first high-pressure relief valve 1-3 and the second high-pressure relief valve 1-4 are respectively connected to the travel pump 1-1, the hydraulic oil tank 24, the steering pump 1-6 and the travel motor 1-7 through pipelines. The steering pump 1-6 is respectively connected to the gearbox 3 and the steering valve 2 through pipelines. The travel motor 1-7 is driven by the gearbox 3. The variable motor control valve 1-8 is respectively connected to the travel motor 1-7 and the variable pump control valve 1-9 through pipelines. The variable pump control valve 1-9 is connected to the travel pump 1-1 through pipelines.

[0048] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the travel and steering system is working, the travel HST is a closed system. A replenishing pump and a steering pump are connected in series on the pump shaft of the travel HST. The replenishing pump draws oil from the hydraulic oil tank through the second suction filter, and the oil enters the travel HST to complete control actions and replenish leaks. The steering pump draws oil from the gearbox housing through the steering suction filter and the steering radiator, and then enters the steering valve through the steering filter. The travel pump can achieve stepless displacement control through a variable pump control valve, and the travel motor can achieve stepless or multi-point displacement control through a variable motor control valve. The controller reads vehicle speed through a speed sensor and travel pressure through a first and second pressure sensor. Using a travel control strategy, it controls the displacement of the travel pump and travel motor of the travel HST. Low pressure switches to a smaller travel motor displacement, and vice versa. Low speed switches to a larger travel pump displacement, and vice versa, achieving automatic vehicle speed control. During short-distance relocation, the travel motor displacement can be automatically or manually switched to a smaller displacement, improving work efficiency and saving energy. By integrating with BeiDou navigation and steering valves, it achieves unmanned automatic control.

[0049] like Figures 1 to 4 As shown, the oil replenishment pump 1-5 is further connected to a fan backflush valve 14 or a proportional solenoid valve via a pipeline. The fan backflush valve 14 or the proportional solenoid valve is connected to a hydraulic commutator fan 13 for cooling the engine 18 and an ECU 19. The hydraulic commutator fan 13 is located at the end of the engine 18. The ECU 19 is connected to the controller 20. The oil replenishment overflow valve 1-2 is connected to the fan backflush valve 14 or the proportional solenoid valve via a pipeline.

[0050] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the travel steering system is working, the travel HST is a closed system. A replenishing pump and a steering pump are connected in series on the pump shaft of the travel HST. After the replenishing pump draws oil from the hydraulic oil tank through the second suction filter, a portion of the oil enters the travel HST to complete control actions and replenish leaks, while the other portion enters the hydraulic reversing fan through the fan backflush valve 14, realizing the reversing of the hydraulic reversing fan and completing the backflush action. The steering pump draws oil from the gearbox housing through the steering suction filter and the steering radiator, and enters the steering valve through the steering filter. The controller reads the oil temperature through the temperature sensor and sends it to the ECU. When the set temperature value is reached, Y17 of the fan backflush valve 14 is energized, executing the fan backflush command. When the oil temperature does not reach the set value, the backflush action is executed according to the set time interval. When the oil temperature is lower than a certain set value, the fan backflush valve 14 does not work and does not execute the reversing action. The fan backflush valve 14 can be replaced with a proportional solenoid valve. A flow meter is added after the valve to collect the output flow signal. By controlling the output flow, the stepless speed regulation control of the hydraulic reversing fan is realized, which saves energy and reduces consumption.

[0051] The first pressure sensor 1-10 and the second pressure sensor 1-11 detect the forward and backward travel pressure of the HST1, respectively, and are installed on the pressure measuring port of the HST1. Low pressure switches to the smaller displacement travel motor 1-7, and vice versa. Low speed switches to the larger displacement travel pump 1-1, and vice versa. For short-distance relocation, the smaller displacement of the travel motor 1-7 can be switched automatically or manually. The motor displacement is an internal structural feature and is generally agreed upon in the industry. The exact size is determined by pressure and speed. The hydraulic reversing fan 13, also known as the engine cooling fan, is located at the engine end and dissipates heat from the engine.

[0052] like Figures 1 to 4As shown, further, the steering valve 2 includes: an overflow valve 2-1, an unloading valve 2-2, a right clutch solenoid valve 2-3, a left clutch solenoid valve 2-4, a proportional pressure reducing valve 2-5, and a steering switching valve 2-6. The gearbox 3 includes: a housing 3-1, a left clutch 3-2, a right clutch 3-3, a steering clutch 3-4, and a soft clutch 3-5. The overflow valve 2-1 is connected to the housing 3-1, the travel HST, the unloading valve 2-2, and the right clutch solenoid valve 2-3 via pipelines. The unloading valve 2-2 is connected to the housing 3-1, the travel HST, and the right clutch solenoid valve 2-6 via pipelines. The right clutch solenoid valve 2-3 is connected to the left clutch solenoid valve 2-4, the steering switching valve 2-6, the housing 3-1, and the right clutch 3-3 via pipelines. The left clutch solenoid valve 2-4 is connected to the housing 3-1 and the left clutch 3-2 via pipelines. The proportional pressure reducing valve 2-5 is connected to the housing 3-1, the steering switching valve 2-6, the left clutch 3-2, and the right clutch 3-3 via pipelines. The steering switching valve 2-6 is connected to the housing 3-1, the steering clutch 3-4, and the soft clutch 3-5 via pipelines.

[0053] The beneficial effects of adopting the above-mentioned further technical solution are as follows: when not steering, the unloading valve Y1 is energized; when fine-tuning steering, the right clutch solenoid valve Y3 or the left clutch solenoid valve Y2 is energized; when differential steering, the proportional pressure reducing valve Y4 and the left clutch solenoid valve Y2 or the right clutch solenoid valve Y3 are energized; when braking on one side and turning in place, the proportional pressure reducing valve Y4, the steering switching valve Y5 and the left clutch solenoid valve Y2 or the right clutch solenoid valve Y3 are energized; when braking on one side, the steering clutch pressure is low and there is no power output. The drive shaft corresponding to steering clutches 3-4 receives power from the travel HST1, and the output end is the drive shaft, ultimately corresponding to the track drive wheel.

[0054] The steering clutch and soft clutch are also clutches inside the gearbox. When the soft clutch is engaged, it can reduce the speed of the outer drive shaft (e.g., for left or right turns) to achieve slow steering. When the steering clutch is engaged, it can reduce the speed of the outer drive shaft or reverse the direction of the drive shaft (achieved by increasing pressure) to achieve single-sided braking or turning on the spot.

[0055] When unloading valve 2-2 is energized, there is no steering action, and the oil returns directly. When right clutch solenoid valve 2-3 or left clutch solenoid valve 2-4 is energized, the corresponding left and right clutches of the gearbox (right clutch 3-3 and left clutch 3-2) are disengaged, and power is lost on the left or right side, enabling fine-tuning of the steering.

[0056] When the proportional pressure reducing valve 2-5, the right clutch solenoid valve 2-3, or the left clutch solenoid valve 2-4 is energized, the left or right side loses power, and the soft clutch 3-5 engages. This allows the speed of the outer (e.g., turning left or right) drive shaft to be reduced through the drive shaft, thus achieving slow (differential) steering.

[0057] When the proportional pressure reducing valve 2-5, steering switching valve 2-6, right clutch solenoid valve 2-3, or left clutch solenoid valve 2-4 is energized, the left or right side loses power, the steering clutch 3-4 engages, and the speed of the outer side can be reduced by the drive shaft or the direction of the drive shaft can be reversed (this can be achieved by increasing the pressure), thereby realizing single-sided braking or turning in place.

[0058] Furthermore, the travel HST1 is an electronically controlled stepless speed-regulating travel HST, and the steering valve 2 is an electronically controlled steering valve.

[0059] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The steering valve is electronically controlled, and in conjunction with the gearbox, it can achieve four steering modes: fine-tuning steering, differential steering, single-sided braking, and stationary steering, thus realizing the stationary steering function and adapting to various working conditions. The travel HST uses an electronically controlled stepless speed regulation method, and the travel pump can achieve stepless displacement control through a variable pump control valve, while the travel motor can achieve stepless or multi-point displacement control through a variable motor control valve.

[0060] like Figures 1 to 4As shown, the control valve 4 further includes: a main relief valve 4-1, an enabling valve 4-2, a header priority valve 4-3, a header relief valve 4-4, a header rise proportional valve 4-5, a pressure compensator 4-6, a header descent proportional valve 4-7, a right chassis lift proportional valve 4-8, multiple hydraulic locks 4-9, a left chassis lift proportional valve 4-10, a reel control valve 4-11, and a grain unloading control valve 4-12. The two ends of the main relief valve 4-1 and the enabling valve... Both ends of valve 4-2 are connected to the working pump 16 and the hydraulic oil tank 24 respectively via pipelines. Port 1 of the header priority valve 4-3 is connected to the working pump 16 via a pipeline. Port 2 of the header priority valve 4-3 is connected to the header lifting proportional valve 4-5 via a pipeline. Port 3 of the header priority valve 4-3 is connected to the right chassis lifting proportional valve 4-8, the left chassis lifting proportional valve 4-10, and the reel control valve 4-10 via pipelines. The unloading control valve 4-11 is connected to the unloading control valve 4-12. The two ends of the header overflow valve 4-4 are connected to the header priority valve 4-3 and the hydraulic oil tank 24 respectively through pipelines. The header descent proportional valve 4-7 is connected to the hydraulic oil tank 24 through the pressure compensator 4-6. The working device includes: unloading cylinder 5, reel cylinder 6 and header cylinder 12. The unloading control valve 4-12 is connected to the unloading cylinder 5 through the hydraulic lock 4-9. The reel control valve 4-11 is connected to the reel cylinder 6 through the hydraulic lock 4-9. The left chassis lifting proportional valve 4-10 is connected to the left chassis lifting cylinder 8 through the hydraulic lock 4-9. The right chassis lifting proportional valve 4-8 is connected to the right chassis lifting cylinder 11 through the hydraulic lock 4-9. The header descent proportional valve 4-5 and the header descent proportional valve 4-7 are connected to the header cylinder 12 through pipelines.

[0061] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the working device is working, the working pump draws oil from the hydraulic oil tank through the first suction filter, and then enters the P port of the control valve through the first filter. When the working device is not working, the oil flows back to the hydraulic oil tank through the T port of the enable valve. When the working device is working, the enable valve is energized to switch functions. When the cutting platform is lifted, the oil flow is distributed by the cutting platform priority valve according to the opening of the cutting platform lifting proportional valve. The flow from port 2 of the cutting platform priority valve preferentially enters the cutting platform cylinder through the cutting platform lifting proportional valve to realize the lifting of the cutting platform. The remaining flow enters the subsequent working valve through port 3 of the cutting platform priority valve. The cutting platform cylinder can connect with the right side bottom... The lifting cylinders of the header, left chassis, reel, and unloading cylinders perform combined actions. When the header descends, the header descent proportional valve is energized, and the descent speed is controlled by the current-controlled valve opening. Oil flows back to the oil tank from port T through the header descent proportional valve and pressure compensator. The pressure compensator maintains a constant pressure difference across the header descent proportional valve, improving the stability of the header descent speed. When other working devices are operating and the header is not, all oil flows through port 3 of the header priority valve, through the right or left chassis lifting proportional valve, reel control valve, or unloading control valve, to the corresponding actuator to complete the corresponding action. The controller reads signals from the vehicle body attitude sensor to control the left and right chassis lifting cylinders. By reading signals from the first and second angle sensors, it achieves automatic leveling closed-loop control of the chassis lifting. Manual control is possible under special working conditions to improve operational comfort and maneuverability. Hydraulic locks are installed on the control valve oil lines corresponding to the right chassis lifting cylinder, left chassis lifting cylinder, reel cylinder, and unloading cylinder to prevent excessive static settlement.

[0062] like Figures 1 to 4 As shown, further, a first filter 15 is installed on the pipeline between the control valve 4 and the working pump 16, and a first suction filter 17 is installed on the pipeline between the working pump 16 and the hydraulic oil tank 24; a first radiator 23, a second suction filter 26, a steering suction filter 27, and a steering radiator 28 are installed on the pipeline between the travel HST1 and the hydraulic oil tank 24; a hydraulic oil tank breather 25 is installed on the hydraulic oil tank 24; a gearbox breather 29 is installed on the gearbox 3; and a steering filter 30 is installed on the pipeline between the travel HST1 and the steering valve 2.

[0063] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the filter and oil suction filter are used to filter impurities in the oil, preventing impurities from entering the system and improving the stability and reliability of the system. The radiator is used to cool the oil and prevent it from overheating. The breather is used to allow ventilation between the oil tank and the gearbox and the outside environment.

[0064] The present invention provides a hydraulic control system for a harvester, which can be used for an unmanned drive-by-wire chassis tracked harvester. Figures 1 to 4The system shown mainly consists of a walking HST1, a steering valve 2, a gearbox 3, a control valve 4, a grain unloading cylinder 5, a reel cylinder 6, a first angle sensor 7, a left chassis lifting cylinder 8, a vehicle posture sensor 9, a second angle sensor 10, a right chassis lifting cylinder 11, a header cylinder 12, a hydraulic reversing fan 13, a fan backflush valve 14, a first filter 15, a working pump 16, a first oil suction filter 17, an engine 18, an ECU 19, a controller 20, a temperature sensor 21, a Beidou navigation system 22, a first radiator 23, a hydraulic oil tank 24, a hydraulic oil tank breather 25, a second oil suction filter 26, a steering oil suction filter 27, a steering radiator 28, a gearbox breather 29, a steering filter 30, and a speed sensor 31. The HST1 (Travel System) includes a travel pump 1-1, a replenishing overflow valve 1-2, a first high-pressure overflow valve 1-3, a second high-pressure overflow valve 1-4, a replenishing pump 1-5, a steering pump 1-6, a travel motor 1-7, a variable displacement motor control valve 1-8, a variable displacement pump control valve 1-9, a first pressure sensor 1-10, and a second pressure sensor 1-11; the steering valve 2 includes an overflow valve 2-1, an unloading valve 2-2, a right clutch solenoid valve 2-3, a left clutch solenoid valve 2-4, a proportional pressure reducing valve 2-5, and a steering switching valve 2-6; the gearbox 3 mainly includes a housing 3-1 and a left clutch 3-2 (left clutch L in the figure). The control valves include: right clutch 3-3 (R in the diagram), steering clutch 3-4 (Z in the diagram), and soft clutch 3-5 (S in the diagram); control valve 4 includes main relief valve 4-1, enabling valve 4-2, header priority valve 4-3, header relief valve 4-4, header rise proportional valve 4-5, pressure compensator 4-6, header fall proportional valve 4-7, right chassis lift proportional valve 4-8, hydraulic lock 4-9 (up to 4), left chassis lift proportional valve 4-10, reel control valve 4-11, and unloading control valve 4-12; its specific working principle is as follows: The unmanned drive-by-wire chassis tracked machine's HST1 and working pump 16 are driven by engine 18. The working pump 16 is connected to the hydraulic oil tank 24 and control valve 4 through pipelines. The unloading oil cylinder 5, the reel cylinder 6, the left chassis lifting cylinder 8, the right chassis lifting cylinder 11, and the header cylinder 12 are connected to control valve 4 through pipelines. The steering valve 2 is bolted to the gearbox 3 and achieves steering control through internal oil passages. The HST1 is bolted to the gearbox 3 and transmits power to the gearbox 3 through the travel motors 1-7. The ECU 19 is connected to engine 18 and fan backflush valve 14. The controller 20 is connected to ECU 19, Beidou navigation 22, temperature sensor 21, speed sensor 31, first angle sensor 7, second angle sensor 10, vehicle posture sensor 9, HST1, steering valve 2, and control valve 4.

[0065] It can turn on the spot and is lightweight, so the load is small; the use of the HST1 walking system and steering valve 2 system makes it lightweight and low-cost. Because the chassis can be raised or lowered or automatically adjusted in height and can turn on the spot with a small turning radius, it is well adapted to working on slopes, deep muddy fields and smooth crossing of embankments.

[0066] In addition, the present invention also provides a harvester, including the harvester hydraulic control system described above.

[0067] In addition, the present invention also provides a hydraulic control method for a harvester. Based on the above-described hydraulic control system for a harvester, the hydraulic control method for a harvester includes: when the working device is working, the engine 18 drives the working pump 16 to draw oil from the hydraulic oil tank 24 and deliver it to the control valve 4, and the controller 20 controls the control valve 4 to distribute the oil to the working device, so that the working device works; when traveling and turning, the engine 18 drives the traveling HST1 to draw oil from the gearbox 3 and deliver it to the steering valve 2, and the controller 20 controls the steering valve 2 to distribute the oil to the gearbox 3, so as to realize fine-tuning steering, differential steering, single-sided braking and stationary turning.

[0068] The unmanned drive-by-wire chassis tracked vehicle can be divided into a working device system and a walking and steering system. When the working device is working, the working pump 16 draws oil from the hydraulic oil tank 24 through the first suction filter 17, and then enters the P port of the control valve 4 through the first filter 15. When the working device is not working, the oil flows back to the hydraulic oil tank 24 through the T port of the enable valve 4-2. When the working device is working, the enable valve 4-2 is energized to switch functions. When the cutter head is lifted, the oil flow is distributed through the cutter head priority valve 4-3 according to the opening of the cutter head lifting proportional valve 4-5. The flow from port 2 of the cutter head priority valve 4-3 preferentially enters the cutter head cylinder 12 through the cutter head lifting proportional valve 4-5 to achieve cutter head lifting. The remaining flow enters the subsequent working valve through port 3 of the cutter head priority valve 4-3. The cutter head cylinder 12 can be connected to the right chassis lifting cylinder 11 and the left chassis lifting cylinder 12. The chassis lifting cylinder 8, the reel cylinder 6, and the unloading cylinder 5 perform combined actions. When the header descends, the header descent proportional valve 4-7 is energized, and the descent speed is controlled by the opening of the current control valve. The oil flows back to the oil tank from port T through the header descent proportional valve 4-7 and the pressure compensator 4-6. The pressure compensator 4-6 maintains a constant pressure difference before and after the header descent proportional valve 4-7, improving the stability of the header descent speed. When other working devices are working and the header is not working, all the oil flows through port 3 of the header priority valve 4-3 through the right chassis lifting proportional valve 4-8, the left chassis lifting proportional valve 4-10, the reel control valve 4-11, or the unloading control valve 4-12 to the corresponding actuator to complete the corresponding action. When the travel and steering system is working, the travel HST1 is a closed system. A replenishing pump 1-5 and a steering pump 1-6 are connected in series on the pump shaft of the travel HST1. The replenishing pump 1-5 draws oil from the hydraulic oil tank 24 via the second suction filter 26. A portion of the oil enters the travel HST1 to complete control actions and replenish leaks, while the other portion enters the hydraulic reversing fan 13 via the fan backflush valve 14, enabling the hydraulic reversing fan 13 to reverse and complete the backflush action. The steering pump 1-6 draws oil from the housing 3-1 of the gearbox 3 via the steering suction filter 27 and the steering radiator 28, and then enters the steering valve via the steering filter 30. 2. When not steering, Y1 of unloading valve 2-2 is energized. When fine-tuning steering, Y3 of right clutch solenoid valve 2-3 or Y2 of left clutch solenoid valve 2-4 is energized. When differential steering, Y4 of proportional pressure reducing valve 2-5 and Y2 of left clutch solenoid valve 2-4 or Y3 of right clutch solenoid valve 2-3 are energized. When braking on one side and turning in place, Y4 of proportional pressure reducing valve 2-5, Y5 of steering switching valve 2-6 and Y2 of left clutch solenoid valve 2-4 or Y3 of right clutch solenoid valve 2-3 are energized. When braking on one side, the steering clutch 3-4 has low pressure and no power output (see steering control action). Figure 5 and Figure 8 ).

[0069] like Figure 1 and Figure 3As shown, the unloading valve 2-2, left clutch solenoid valve 2-4, right clutch solenoid valve 2-3, proportional pressure reducing valve 2-5, and steering switching valve 2-6 each have two switching positions. When the unloading valve 2-2 is in position Y1, both ends of the pipeline are open; in the other position, both ends of the pipeline are closed. When the left clutch solenoid valve 2-4 is in position Y2, both ends of the pipeline are open; in the other position, both ends of the pipeline are closed. When the right clutch solenoid valve 2-3 is in position Y3, both ends of the pipeline are open; in the other position, both ends of the pipeline are closed. When the proportional pressure reducing valve 2-5 is in position Y4, both ends of the pipeline are open; in the other position, both ends of the pipeline are closed. When the steering switching valve 2-6 is in position Y5, both ends of the pipeline are open; in the other position, both ends of the pipeline are closed.

[0070] Figure 8 The table showing the control actions of the steering valve assembly is provided. Figure 5 The system control action execution summary table is shown. In the neutral position (no steering), unloading valve 2-2 is energized and in position Y1; left clutch solenoid valve 2-4 is de-energized and not in position Y2; right clutch solenoid valve 2-3 is de-energized and not in position Y3; proportional pressure reducing valve 2-5 is de-energized and not in position Y4; and steering switching valve 2-6 is de-energized and not in position Y5. Unloading valve 2-2 being energized and in position Y1 can mean that when unloading valve 2-2 is energized, the electromagnet of unloading valve 2-2 attracts the valve core to position Y1.

[0071] When fine-tuning the steering to the left, unloading valve 2-2 is not energized and is not in position Y1, left clutch solenoid valve 2-4 is energized and is in position Y2, right clutch solenoid valve 2-3 is not energized and is not in position Y3, proportional pressure reducing valve 2-5 is not energized and is not in position Y4, and steering switching valve 2-6 is not energized and is not in position Y5.

[0072] When fine-tuning the steering to the right, unloading valve 2-2 is not energized and is not in position Y1, left clutch solenoid valve 2-4 is not energized and is not in position Y2, right clutch solenoid valve 2-3 is energized and is in position Y3, proportional pressure reducing valve 2-5 is not energized and is not in position Y4, and steering switching valve 2-6 is not energized and is not in position Y5.

[0073] When differential steering is to the left, unloading valve 2-2 is not energized and is not in position Y1, left clutch solenoid valve 2-4 is energized and is in position Y2, right clutch solenoid valve 2-3 is not energized and is not in position Y3, proportional pressure reducing valve 2-5 is energized and is in position Y4, and steering switching valve 2-6 is not energized and is not in position Y5.

[0074] When differential steering is to the right, unloading valve 2-2 is not energized and is not in position Y1, left clutch solenoid valve 2-4 is not energized and is not in position Y2, right clutch solenoid valve 2-3 is energized and is in position Y3, proportional pressure reducing valve 2-5 is energized and is in position Y4, and steering switching valve 2-6 is not energized and is not in position Y5.

[0075] When braking on one side to the left, unloading valve 2-2 is not energized and is not in position Y1, left clutch solenoid valve 2-4 is energized and is in position Y2, right clutch solenoid valve 2-3 is not energized and is not in position Y3, proportional pressure reducing valve 2-5 is energized and is in position Y4, and steering switching valve 2-6 is energized and is in position Y5.

[0076] When braking on one side to the right, unloading valve 2-2 is not energized and is not in position Y1, left clutch solenoid valve 2-4 is not energized and is not in position Y2, right clutch solenoid valve 2-3 is energized and is in position Y3, proportional pressure reducing valve 2-5 is energized and is in position Y4, and steering switching valve 2-6 is energized and is in position Y5.

[0077] When turning left from a stationary position, unloading valve 2-2 is not energized and is not in position Y1, left clutch solenoid valve 2-4 is energized and is in position Y2, right clutch solenoid valve 2-3 is not energized and is not in position Y3, proportional pressure reducing valve 2-5 is energized and is in position Y4, and steering switching valve 2-6 is energized and is in position Y5.

[0078] When turning right from a stationary position, unloading valve 2-2 is not energized and is not in position Y1, left clutch solenoid valve 2-4 is not energized and is not in position Y2, right clutch solenoid valve 2-3 is energized and is in position Y3, proportional pressure reducing valve 2-5 is energized and is in position Y4, and steering switching valve 2-6 is energized and is in position Y5.

[0079] like Figure 1 and Figure 4As shown, when the enabling valve 4-2 is in position Y16, the two ends of the pipeline are connected, and a check valve is installed between the two ends of the pipeline to prevent backflow. In the other position, the two ends of the pipeline are directly connected. When the header lifting proportional valve 4-5 is in position Y15, the two ends of the pipeline are connected, and a first check valve is installed between the two ends of the pipeline, allowing the oil in the system to enter the header cylinder 12 in one direction, causing the header cylinder 12 to extend. In the other position, the two ends of the pipeline are connected, and a second check valve is installed between the two ends of the pipeline, allowing the oil in the header cylinder 12 to enter the system in one direction. When the header lowering proportional valve 4-7 is in position Y14, the two ends of the pipeline are connected, and a third check valve is installed between the two ends of the pipeline, allowing the oil in the header cylinder 12 to enter the system in one direction, causing the header cylinder 12 to retract. In the other position, the two ends of the pipeline are connected, and a fourth check valve is installed between the two ends of the pipeline, allowing the oil in the system to enter the header cylinder 12 in one direction. When the right chassis lifting proportional valve 4-8 is in position Y13, the pair of pipes at both ends are directly connected. When the right chassis lifting proportional valve 4-8 is in position Y12, the pair of pipes at both ends are connected after reversing. When the left chassis lifting proportional valve 4-10 is in position Y11, the pair of pipes at both ends are directly connected. When the left chassis lifting proportional valve 4-10 is in position Y10, the pair of pipes at both ends are connected after reversing. When the reel control valve 4-11 is in position Y9, the pair of pipes at both ends are directly connected. When the reel control valve 4-11 is in position Y8, the pair of pipes at both ends are connected after reversing. When the unloading control valve 4-12 is in position Y7, the pair of pipes at both ends are directly connected. When the unloading control valve 4-12 is in position Y6, the pair of pipes at both ends are connected after reversing. When the fan backflush valve 14 is in position Y17, the pipes at both ends are connected, and the system oil enters the hydraulic reversing fan 13.

[0080] Figure 6 The table showing the control actions of the working valve group is provided. Figure 5 The system control action execution table is shown. Specifically, when the header rises, enable valve 4-2 is energized and in position Y16; header rise proportional valve 4-5 is energized and in position Y15; header fall proportional valve 4-7 is de-energized and not in position Y14; right chassis lift proportional valve 4-8 is de-energized and not in positions Y13 and Y12; left chassis lift proportional valve 4-10 is de-energized and not in positions Y11 and Y10; reel control valve 4-11 is de-energized and not in positions Y9 and Y8; and unloading control valve 4-12 is de-energized and not in positions Y7 and Y6.

[0081] When the header lowers, enable valve 4-2 is energized and in position Y16; header lifting proportional valve 4-5 is de-energized and not in position Y15; header lowering proportional valve 4-7 is energized and in position Y14; right chassis lifting proportional valve 4-8 is de-energized and not in positions Y13 and Y12; left chassis lifting proportional valve 4-10 is de-energized and not in positions Y11 and Y10; reel control valve 4-11 is de-energized and not in positions Y9 and Y8; and unloading control valve 4-12 is de-energized and not in positions Y7 and Y6.

[0082] It should be noted that the header lifting (header raising or lowering) can be synchronized with the subsequent chassis lifting, reel lifting, and unloading hopper lifting in any combination. The header priority valve 4-3 prioritizes the header lifting, and the remaining system flow is used for the actions of the subsequent devices (chassis lifting, reel lifting, and unloading hopper lifting). Therefore, the header action can work simultaneously with other actions to achieve compound actions. When there is no requirement for simultaneous action, the above description applies.

[0083] When the chassis rises to the left, the enabling valve 4-2 is energized and is in position Y16; the header lifting proportional valve 4-5 is de-energized and is not in position Y15; the header lowering proportional valve 4-7 is de-energized and is not in position Y14; the right chassis lifting proportional valve 4-8 is de-energized and is not in positions Y13 and Y12; the left chassis lifting proportional valve 4-10 is energized and is in position Y11, but not in position Y10; the reel control valve 4-11 is de-energized and is not in positions Y9 and Y8; and the unloading control valve 4-12 is de-energized and is not in positions Y7 and Y6.

[0084] When the chassis lowers to the left, the enabling valve 4-2 is energized and is in position Y16; the header lifting proportional valve 4-5 is de-energized and is not in position Y15; the header lowering proportional valve 4-7 is de-energized and is not in position Y14; the right chassis lifting proportional valve 4-8 is de-energized and is not in positions Y13 and Y12; the left chassis lifting proportional valve 4-10 is energized and is not in position Y11, but in position Y10; the reel control valve 4-11 is de-energized and is not in positions Y9 and Y8; and the unloading control valve 4-12 is de-energized and is not in positions Y7 and Y6.

[0085] When the chassis rises to the right, the enabling valve 4-2 is energized and is in position Y16; the header lifting proportional valve 4-5 is de-energized and is not in position Y15; the header lowering proportional valve 4-7 is de-energized and is not in position Y14; the right chassis lifting proportional valve 4-8 is energized and is in position Y13, not in position Y12; the left chassis lifting proportional valve 4-10 is de-energized and is not in positions Y11 and Y10; the reel control valve 4-11 is de-energized and is not in positions Y9 and Y8; and the unloading control valve 4-12 is de-energized and is not in positions Y7 and Y6.

[0086] When the chassis descends to the right, the enabling valve 4-2 is energized and is in position Y16; the header lifting proportional valve 4-5 is de-energized and is not in position Y15; the header lowering proportional valve 4-7 is de-energized and is not in position Y14; the right chassis lifting proportional valve 4-8 is energized and is not in position Y13, but in position Y12; the left chassis lifting proportional valve 4-10 is de-energized and is not in positions Y11 and Y10; the reel control valve 4-11 is de-energized and is not in positions Y9 and Y8; and the unloading control valve 4-12 is de-energized and is not in positions Y7 and Y6.

[0087] It should be noted that the left-side lifting (left-side lifting and left-side lowering) and right-side lifting (right-side lifting and right-side lowering) of the chassis can both operate individually or simultaneously. When there is no requirement for simultaneous operation, the above description applies.

[0088] When the reel rises, the enabling valve 4-2 is energized and is in position Y16; the header raising proportional valve 4-5 is de-energized and is not in position Y15; the header lowering proportional valve 4-7 is de-energized and is not in position Y14; the right chassis lifting proportional valve 4-8 is de-energized and is not in positions Y13 and Y12; the left chassis lifting proportional valve 4-10 is de-energized and is not in positions Y11 and Y12; the reel control valve 4-11 is energized and is in position Y9, not in position Y8; and the unloading control valve 4-12 is de-energized and is not in positions Y7 and Y6.

[0089] When the reel descends, the enabling valve 4-2 is energized and is in position Y16; the header raising proportional valve 4-5 is de-energized and is not in position Y15; the header lowering proportional valve 4-7 is de-energized and is not in position Y14; the right chassis lifting proportional valve 4-8 is de-energized and is not in positions Y13 and Y12; the left chassis lifting proportional valve 4-10 is de-energized and is not in positions Y11 and Y10; the reel control valve 4-11 is energized and is not in position Y9, but in position Y8; and the unloading control valve 4-12 is de-energized and is not in positions Y7 and Y6.

[0090] When the grain is unloaded and raised, the enabling valve 4-2 is energized and is in position Y16; the header raising proportional valve 4-5 is energized and is in position Y15; the header lowering proportional valve 4-7 is de-energized and is not in position Y14; the right chassis lifting proportional valve 4-8 is de-energized and is not in positions Y13 and Y12; the left chassis lifting proportional valve 4-10 is de-energized and is not in positions Y11 and Y10; the reel control valve 4-11 is de-energized and is not in positions Y9 and Y8; and the unloading control valve 4-12 is energized and is in position Y7, not in position Y6.

[0091] When the grain unloading is lowered, the enabling valve 4-2 is energized and is in position Y16; the header lifting proportional valve 4-5 is de-energized and is not in position Y15; the header lowering proportional valve 4-7 is de-energized and is not in position Y14; the right chassis lifting proportional valve 4-8 is de-energized and is not in positions Y13 and Y12; the left chassis lifting proportional valve 4-10 is de-energized and is not in positions Y11 and Y10; the reel control valve 4-11 is de-energized and is not in positions Y9 and Y8; and the grain unloading control valve 4-12 is energized and is not in position Y7, but in position Y6.

[0092] When the hydraulic fan is blowing back, the fan backflush valve 14 is energized and in position Y17.

[0093] like Figure 1 and Figure 2 As shown, when the variable pump control valve 1-9 is in position Y18, the hydraulic fluid is connected to the reversing line of the travel pump 1-1. When the variable pump control valve 1-9 is in position Y19, the hydraulic fluid is connected to the forward line of the travel pump 1-1. When the variable motor control valve 1-8 is in position Y20, the two ends of the pair of pipes are directly connected, and the hydraulic fluid enters the small chamber of the variable cylinder of the travel motor 1-7, pushing the motor's variable swashplate, thus reducing the motor's displacement and achieving the motor's small displacement function. When the variable motor control valve 1-8 is not in position Y20, the two ends of the pair of pipes are reversed and connected, and the hydraulic fluid enters the large chamber of the variable cylinder of the travel motor 1-7, pushing the motor's variable swashplate, thus increasing the motor's displacement and achieving the motor's large displacement function.

[0094] Figure 7 The control action execution table for the travel valve assembly is shown. Figure 5 The system control action execution summary table is shown. Specifically, during forward movement, variable pump control valves 1-9 are energized and not in position Y18; when in position Y19, variable motor control valves 1-8 are de-energized and not in position Y20.

[0095] When moving forward or backward, the variable pump control valve 1-9 is energized and in position Y18, but not in position Y19; the variable motor control valve 1-8 is de-energized and not in position Y20.

[0096] It should be noted that the above-mentioned variable motor control valves 1-8 being de-energized and not in the Y20 position is only one implementation method. When moving forward or backward, the motor displacement can be selected according to the working conditions. That is, when moving forward or backward, the variable motor control valves 1-8 can be energized and in the Y20 position.

[0097] When the motor has a large displacement, the variable pump control valves 1-9 should not be energized and should not be in position Y18 or Y19. The variable motor control valves 1-8 should not be energized and should not be in position Y20.

[0098] When the motor has a small displacement, the variable pump control valves 1-9 are not energized and are not in position Y18 or Y19, while the variable motor control valves 1-8 are energized and are in position Y20.

[0099] It should be noted that the above statement that the variable pump control valves 1-9 are not energized and are not in position Y18 or Y19 is only one implementation method. When moving forward or backward, the motor displacement can be selected according to the operating conditions. That is, when the motor has a large displacement, or when the motor has a small displacement, the variable pump control valves 1-9 are energized and in position Y18, not in position Y19, or the variable pump control valves 1-9 are energized and not in position Y18, but in position Y19.

[0100] In the diagram, P is the oil inlet, and T, T1, and T2 are the oil return ports, which are connected to the oil tank via pipelines. The GYRO sensor is a device used to measure angular velocity, also known as a gyroscope sensor, i.e., the vehicle attitude sensor 9. P0, P1, P2, P3, P4, and P5 can all be pressure sensors. In the diagram, n is the speed sensor 31. In the diagram, t° can be the temperature sensor 21. M is the engine 18. P6 is the first pressure sensor 1-10, and P7 is the second pressure sensor 1-11. The M and A ports on the fan backflush valve 14 are connected to the oil inlet P and the hydraulic reversing fan 13 via pipelines, respectively. ML and MR, which are connected to the left clutch solenoid valve 2-4 and the right clutch solenoid valve 2-3, are the left expansion interface and the right expansion interface, respectively.

[0101] Furthermore, the steering valve 2 is electronically controlled, and in conjunction with the gearbox 3, it can realize four steering modes: fine-tuning steering, differential steering, single-sided braking, and stationary steering, thus achieving the stationary steering function and adapting to various working conditions.

[0102] Furthermore, the HST1 is equipped with an electronically controlled stepless speed regulation system. The displacement of the travel pump 1-1 can be steplessly controlled via the variable pump control valve 1-9, and the displacement of the travel motor 1-7 can be steplessly or multi-point controlled via the variable motor control valve 1-8. The controller 20 reads the vehicle speed through the speed sensor 31 and the travel pressure through the first pressure sensor 1-10 and the second pressure sensor 1-11. Through the travel control strategy, the displacement of the travel pump 1-1 and the travel motor 1-7 of the HST1 is controlled. When the pressure is low, the travel motor 1-7 switches to a smaller displacement, and vice versa. When the speed is low, the travel pump 1-1 switches to a larger displacement, and vice versa, thus achieving automatic speed control. During short-distance relocation, the travel motor 1-7 can be automatically or manually switched to a smaller displacement to improve work efficiency and save energy. By combining with the Beidou navigation system 22 and the steering valve 2, unmanned automatic control is achieved.

[0103] Furthermore, the controller 20 controls the left chassis lifting cylinder 8 and the right chassis lifting cylinder 11 by reading the signal from the vehicle body posture sensor 9, and realizes automatic leveling closed-loop control of chassis lifting by reading the signals from the first angle sensor 7 and the second angle sensor 10; manual control is possible under special working conditions to improve work comfort and passability.

[0104] Furthermore, the controller 20 reads the oil temperature through the temperature sensor 21 and sends it to the ECU 19. When the set temperature value is reached, the Y17 of the fan backflush valve 14 is energized and the fan backflush command is executed. When the oil temperature does not reach the set value, the backflush action is executed according to the set time interval. When the oil temperature is lower than a certain set value, the fan backflush valve 14 does not work and does not perform the reversing action.

[0105] Furthermore, the fan backflush valve 14 can be replaced with a proportional solenoid valve, and a flow meter can be added after the valve to collect the output flow signal. By controlling the output flow, the stepless speed regulation control of the hydraulic reversing fan 13 can be realized, thereby saving energy and reducing consumption.

[0106] Furthermore, the steering pumps 1-6 can be connected in series with the HST or installed externally, and the steering suction filter 27 and steering filter 30 can be freely combined.

[0107] Furthermore, hydraulic locks 4-9 are installed on the control valves 4 corresponding to the right chassis lifting cylinder 11, the left chassis lifting cylinder 8, the reel cylinder 6, and the unloading cylinder 5 to prevent excessive static settling.

[0108] It is applicable to tracked machines, including but not limited to tracked harvesters and unmanned drive-by-wire chassis tracked machines, solving the problems of high steering load, poor flexibility, heavy weight, and high cost of existing technologies. At the same time, it solves the problems of poor adaptability in slope operation, deep muddy fields, and ridge crossing. Through real-time matching of chassis lifting angle sensor and vehicle posture sensor, and real-time matching of vehicle speed and Beidou navigation, it improves operation quality and efficiency, meets the user's needs for comfortable operation, smooth walking and steering, high cost performance and high adaptability. The mechanical structure is simple, energy consumption is low and weight is light.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydraulic control system for a harvester, characterized in that, include: The system comprises a traveling HST (1), a steering valve (2) for fine-tuning steering, differential steering, single-sided braking, and stationary steering, a gearbox (3), a control valve (4), a working device, a working pump (16), an engine (18), a controller (20), and a hydraulic tank (24). The working device includes a left chassis lifting cylinder (8) and a right chassis lifting cylinder (11). The engine (18) is connected to the traveling HST (1) and the working pump (16) respectively. The working pump (16), the traveling HST (1), and the control valve (4) are all connected to the hydraulic tank (24) through pipelines. The oil tank (24) is connected, the control valve (4) is connected to the working pump (16) through a pipeline, the left chassis lifting cylinder (8) and the right chassis lifting cylinder (11) are both connected to the control valve (4) through pipelines, the travel HST (1) and the steering valve (2) are both installed on the gearbox (3), the travel HST (1) is connected to the gearbox (3) through a pipeline, the gearbox (3) is connected to the travel HST (1) through transmission, and the controller (20) is connected to the travel HST (1), the steering valve (2) and the control valve (4) respectively.

2. The hydraulic control system for a harvester according to claim 1, characterized in that, The controller (20) is connected to a first pressure sensor (1-10) for detecting the forward pressure of the walking HST (1), a second pressure sensor (1-11) for detecting the backward pressure of the walking HST (1), a first angle sensor (7) for detecting the left chassis angle, a second angle sensor (10) for detecting the right chassis angle, a vehicle posture sensor (9) for detecting the vehicle posture, a temperature sensor (21) for detecting the oil temperature, a Beidou navigation system (22), and a speed sensor (31) for detecting the vehicle speed. The first pressure sensor (1-10) and the second pressure sensor (1-11) are respectively connected to the pressure measuring port of the walking HST (1) through pipelines.

3. The hydraulic control system for a harvester according to claim 1, characterized in that, The travel HST (1) includes: a travel pump (1-1), a fuel replenishment overflow valve (1-2), a first high-pressure overflow valve (1-3), a second high-pressure overflow valve (1-4), a fuel replenishment pump (1-5), a steering pump (1-6), a travel motor (1-7), a variable displacement motor control valve (1-8), and a variable displacement pump control valve (1-9). The travel pump (1-1) is driven by the engine (18). The travel pump (1-1) is driven by the fuel replenishment pump (1-5) and the steering pump (1-6). The fuel replenishment overflow valve (1-2) is connected to the variable displacement motor control valve (1-8) and the variable displacement pump control valve (1-9), respectively. A high-pressure relief valve (1-3) and a second high-pressure relief valve (1-4) are connected to the travel pump (1-1), the hydraulic oil tank (24), the steering pump (1-6), and the travel motor (1-7) respectively via pipelines. The steering pump (1-6) is connected to the gearbox (3) and the steering valve (2) respectively via pipelines. The travel motor (1-7) is connected to the gearbox (3) via transmission. The variable motor control valve (1-8) is connected to the travel motor (1-7) and the variable pump control valve (1-9) respectively via pipelines. The variable pump control valve (1-9) is connected to the travel pump (1-1) via pipelines.

4. A harvester hydraulic control system according to claim 3, characterized in that, The oil replenishment pump (1-5) is connected to a fan backflush valve (14) or a proportional solenoid valve via a pipeline. The fan backflush valve (14) or the proportional solenoid valve is connected to a hydraulic commutator fan (13) for cooling the engine (18) and an ECU (19). The hydraulic commutator fan (13) is located at the end of the engine (18). The ECU (19) is connected to the controller (20). The oil replenishment overflow valve (1-2) is connected to the fan backflush valve (14) or the proportional solenoid valve via a pipeline.

5. A hydraulic control system for a harvester according to claim 1, characterized in that, The steering valve (2) includes: an overflow valve (2-1), an unloading valve (2-2), a right clutch solenoid valve (2-3), a left clutch solenoid valve (2-4), a proportional pressure reducing valve (2-5), and a steering switching valve (2-6). The gearbox (3) includes: a housing (3-1), a left clutch (3-2), a right clutch (3-3), a steering clutch (3-4), and a soft clutch (3-5). The overflow valve (2-1) is connected to the housing (3-1), the travel HST (1), the unloading valve (2-2), and the right clutch solenoid valve (2-3) via pipelines. The unloading valve (2-2) is connected to the housing (3-1), the travel HST (1), and the right clutch solenoid valve (2-3) via pipelines. The right clutch solenoid valve (2-3) is connected to the left clutch solenoid valve (2-4), the steering switching valve (2-6), the housing (3-1), and the right clutch (3-3) via pipelines. The left clutch solenoid valve (2-4) is connected to the housing (3-1) and the left clutch (3-2) via pipelines. The proportional pressure reducing valve (2-5) is connected to the housing (3-1), the steering switching valve (2-6), the left clutch (3-2), and the right clutch (3-3) via pipelines. The steering switching valve (2-6) is connected to the housing (3-1), the steering clutch (3-4), and the soft clutch (3-5) via pipelines.

6. A hydraulic control system for a harvester according to claim 1, characterized in that, The walking HST (1) is an electronically controlled stepless speed regulating walking HST, and the steering valve (2) is an electronically controlled steering valve.

7. A hydraulic control system for a harvester according to claim 1, characterized in that, The control valve (4) includes: a main relief valve (4-1), an enabling valve (4-2), a header priority valve (4-3), a header relief valve (4-4), a header rise proportional valve (4-5), a pressure compensator (4-6), a header descent proportional valve (4-7), a right chassis lift proportional valve (4-8), multiple hydraulic locks (4-9), a left chassis lift proportional valve (4-10), a reel control valve (4-11), and a grain unloading control valve (4-12). The two ends of the main relief valve (4-1) and the enabling valve (4-2) are... Both ends of -2) are connected to the working pump (16) and the hydraulic oil tank (24) respectively via pipelines. Port 1 of the cutter priority valve (4-3) is connected to the working pump (16) via a pipeline. Port 2 of the cutter priority valve (4-3) is connected to the cutter lifting proportional valve (4-5) via a pipeline. Port 3 of the cutter priority valve (4-3) is connected to the right chassis lifting proportional valve (4-8), the left chassis lifting proportional valve (4-10), the reel control valve (4-11), and the... The unloading control valve (4-12) is connected to the header overflow valve (4-4), and both ends of the header priority valve (4-3) and the hydraulic oil tank (24) are connected to each other via pipelines. The header descent proportional valve (4-7) is connected to the hydraulic oil tank (24) via the pressure compensator (4-6). The working device includes: unloading cylinder (5), reel cylinder (6), and header cylinder (12). The unloading control valve (4-12) is connected to the unloading cylinder (5) via the hydraulic lock (4-9). The reel control valve (4-11) is connected to the reel cylinder (6) via the hydraulic lock (4-9). The left chassis lifting proportional valve (4-10) is connected to the left chassis lifting cylinder (8) via the hydraulic lock (4-9). The right chassis lifting proportional valve (4-8) is connected to the right chassis lifting cylinder (11) via the hydraulic lock (4-9). The header raising proportional valve (4-5) and the header lowering proportional valve (4-7) are connected to the header cylinder (12) via pipelines.

8. A hydraulic control system for a harvester according to claim 1, characterized in that, A first filter (15) is installed on the pipeline between the control valve (4) and the working pump (16), and a first suction filter (17) is installed on the pipeline between the working pump (16) and the hydraulic oil tank (24); a first radiator (23), a second suction filter (26), a steering suction filter (27), and a steering radiator (28) are installed on the pipeline between the travel HST (1) and the hydraulic oil tank (24); a hydraulic oil tank breather (25) is installed on the hydraulic oil tank (24); a gearbox breather (29) is installed on the gearbox (3); and a steering filter (30) is installed on the pipeline between the travel HST (1) and the steering valve (2).

9. A harvester, characterized in that, The harvester hydraulic control system includes any one of claims 1 to 8.

10. A hydraulic control method for a harvester, characterized in that, Based on any one of claims 1 to 8, the hydraulic control method for a harvester includes: When the working device is working, the engine (18) drives the working pump (16) to draw oil from the hydraulic oil tank (24) and deliver it to the control valve (4). The controller (20) controls the control valve (4) to distribute the oil to the working device, so that the working device can work. When driving and turning, the engine (18) drives the driving HST (1) to draw oil from the gearbox (3) and deliver it to the steering valve (2). The controller (20) controls the steering valve (2) to distribute the oil to the gearbox (3) to achieve fine-tuning steering, differential steering, single-sided braking and stationary steering.

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